Science.gov

Sample records for acidic calcium sulfate

  1. Calcium sulfate crystallization along citrus root channels in a Florida soil exhibiting acid sulfate properties

    SciTech Connect

    Syslo, S.K.; Myhre, D.L.; Harris, W.G.

    1988-02-01

    The authors observed euhedral crystals in Manatee soil in a citrus grove in St. Lucie County, Florida. The material was identified as gypsum (CaSO/sub 4/ /times/ 2H/sub 2/O) using x-ray diffraction and infrared spectra. Photomicrography and scanning electron microscopy revealed that gypsum accumulated both in old root channels and within citrus root tissue of the Btg horizon. The subsurface horizons had elevated sulfate levels, a low initial pH, a drop (0.5 unit) in pH upon air-drying. Electrical conductivity paralleled the concentration of water-soluble sulfate. High levels of calcium and sulfate occurred for horizons above the water table. This accumulation is attributed to groundwater bearing these ions and subsequently discharging them to the overlying soil. Dead citrus roots appear to act as wicks to aid water transfer from lower to higher horizons. The roots and their empty channels provide spaces in which the gypsum can precipitate if the concentrations of calcium and sulfate in the evaporating groundwater exceed the solubility product of gypsum.

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

    NASA Astrophysics Data System (ADS)

    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.

  3. 21 CFR 582.5230 - Calcium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5230 Calcium sulfate. (a) Product. Calcium sulfate. (b) Conditions of use. This...

  4. 21 CFR 582.5230 - Calcium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5230 Calcium sulfate. (a) Product. Calcium sulfate. (b) Conditions of use. This...

  5. 21 CFR 582.5230 - Calcium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5230 Calcium sulfate. (a) Product. Calcium sulfate. (b) Conditions of use. This...

  6. 21 CFR 582.5230 - Calcium sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5230 Calcium sulfate. (a) Product. Calcium sulfate. (b) Conditions of use. This...

  7. 21 CFR 582.5230 - Calcium sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5230 Calcium sulfate. (a) Product. Calcium sulfate. (b) Conditions of use. This...

  8. 21 CFR 184.1230 - Calcium sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium sulfate. 184.1230 Section 184.1230 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1230 Calcium sulfate. (a) Calcium sulfate (CaSO4, CAS Reg. No. 7778-18-9...

  9. 21 CFR 184.1230 - Calcium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium sulfate. 184.1230 Section 184.1230 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Specific Substances Affirmed as GRAS § 184.1230 Calcium sulfate. (a) Calcium sulfate (CaSO4, CAS Reg....

  10. 21 CFR 184.1230 - Calcium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium sulfate. 184.1230 Section 184.1230 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Specific Substances Affirmed as GRAS § 184.1230 Calcium sulfate. (a) Calcium sulfate (CaSO4, CAS Reg....

  11. 21 CFR 184.1230 - Calcium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium sulfate. 184.1230 Section 184.1230 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Specific Substances Affirmed as GRAS § 184.1230 Calcium sulfate. (a) Calcium sulfate (CaSO4, CAS Reg....

  12. 21 CFR 184.1230 - Calcium sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium sulfate. 184.1230 Section 184.1230 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT... GRAS § 184.1230 Calcium sulfate. (a) Calcium sulfate (CaSO4, CAS Reg. No. 7778-18-9 or CaSO4·2H2O,...

  13. Effect of pH and succinic acid on the morphology of α-calcium sulfate hemihydrate synthesized by a salt solution method

    NASA Astrophysics Data System (ADS)

    Li, Fan; Liu, Jianli; Yang, Guangyong; Pan, Zongyou; Ni, Xiao; Xu, Huazi; Huang, Qing

    2013-07-01

    Well-crystallized α-calcium sulfate hemihydrate (α-CSH) powders useful for bone defect filling were synthesized using a salt solution method and their morphologies were effectively modified by adjusting the pH of the reaction solutions or by adding succinic acid. The effect and its mechanism of the pH and the succinic acid on the phase composition and the morphology of the crystals were discussed in detail.

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

    PubMed

    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.

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

    PubMed

    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

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

    SciTech Connect

    Bizzozero, Julien Scrivener, Karen L.

    2015-10-15

    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.

  17. Tantalum oxide and barium sulfate as radiopacifiers in injectable calcium phosphate-poly(lactic-co-glycolic acid) cements for monitoring in vivo degradation.

    PubMed

    Hoekstra, Jan Willem M; van den Beucken, Jeroen J J P; Leeuwenburgh, Sander C G; Bronkhorst, Ewald M; Meijer, Gert J; Jansen, John A

    2014-01-01

    Monitoring the degradation of calcium phosphate-based bone substitute materials in vivo by means of noninvasive techniques (e.g., radiography) is often a problem due to the chemical resemblance of those substitutes with the mineral phase of bone. In the view of that, the present study aimed at enhancing the radiopacity of calcium phosphate cement enriched with poly(lactic-co-glycolic acid) (CPC-PLGA) microspheres, by adding tantalum oxide (Ta2O5) or the more traditional radiopacifier barium sulfate (BaSO4). The radiopacifying capacity of these radiopacifiers was first evaluated in vitro by microcomputed tomography (μCT). Thereafter, both radiopacifiers were tested in vivo using a distal femoral condyle model in rabbits, with subsequent ex vivo μCT analysis in parallel with histomorphometry. Addition of either one of the radiopacifiers proved to enhance radiopacity of CPC-PLGA in vitro. The in vivo experiment showed that both radiopacifiers did not induce alterations in biological performance compared to plain CPC-PLGA, hence both radiopacifiers can be considered safe and biocompatible. The histomorphometrical assessment of cement degradation and bone formation showed similar values for the three experimental groups. Interestingly, μCT analysis showed that monitoring cement degradation becomes feasible upon incorporation of either type of radiopacifier, albeit that BaSO4 showed more accuracy compared to Ta2O5.

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

    PubMed

    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.

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

    PubMed

    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. Mechanics, degradability, bioactivity, in vitro, and in vivo biocompatibility evaluation of poly(amino acid)/hydroxyapatite/calcium sulfate composite for potential load-bearing bone repair.

    PubMed

    Fan, Xiaoxia; Ren, Haohao; Luo, Xiaoman; Wang, Peng; Lv, Guoyu; Yuan, Huipin; Li, Hong; Yan, Yonggang

    2016-03-01

    A ternary composite of poly(amino acid), hydroxyapatite, and calcium sulfate (PAA/HA/CS) was prepared using in situ melting polycondensation method and evaluated in terms of mechanical strengths, in vitro degradability, bioactivity, as well as in vitro and in vivo biocompatibility. The results showed that the ternary composite exhibited a compressive strength of 147 MPa, a bending strength of 121 MPa, a tensile strength of 122 MPa, and a tensile modulus of 4.6 GPa. After immersion in simulated body fluid, the compressive strength of the composite decreased from 147 to 98 MPa for six weeks and the bending strength decreased from 121 to 75 MPa for eight weeks, and both of them kept stable in the following soaking period. The composite could be slowly degraded with 7.27 wt% loss of initial weight after soaking in phosphate buffered solution for three weeks when started to keep stable weight in the following days. The composite was soaked in simulated body fluid solution and the hydroxyapatite layer, as flower-like granules, formed on the surface of the composite samples, showing good bioactivity. Moreover, it was found that the composite could promote proliferation of MG-63 cells, and the cells with normal phenotype extended and spread well on the composite surface. The implantation of the composite into the ulna of sheep confirmed that the composite was biocompatible and osteoconductive in vivo, and offered the PAA/HA/CS composite promising material for load-bearing bone substitutes for clinical application.

  1. Mechanics, degradability, bioactivity, in vitro, and in vivo biocompatibility evaluation of poly(amino acid)/hydroxyapatite/calcium sulfate composite for potential load-bearing bone repair.

    PubMed

    Fan, Xiaoxia; Ren, Haohao; Luo, Xiaoman; Wang, Peng; Lv, Guoyu; Yuan, Huipin; Li, Hong; Yan, Yonggang

    2016-03-01

    A ternary composite of poly(amino acid), hydroxyapatite, and calcium sulfate (PAA/HA/CS) was prepared using in situ melting polycondensation method and evaluated in terms of mechanical strengths, in vitro degradability, bioactivity, as well as in vitro and in vivo biocompatibility. The results showed that the ternary composite exhibited a compressive strength of 147 MPa, a bending strength of 121 MPa, a tensile strength of 122 MPa, and a tensile modulus of 4.6 GPa. After immersion in simulated body fluid, the compressive strength of the composite decreased from 147 to 98 MPa for six weeks and the bending strength decreased from 121 to 75 MPa for eight weeks, and both of them kept stable in the following soaking period. The composite could be slowly degraded with 7.27 wt% loss of initial weight after soaking in phosphate buffered solution for three weeks when started to keep stable weight in the following days. The composite was soaked in simulated body fluid solution and the hydroxyapatite layer, as flower-like granules, formed on the surface of the composite samples, showing good bioactivity. Moreover, it was found that the composite could promote proliferation of MG-63 cells, and the cells with normal phenotype extended and spread well on the composite surface. The implantation of the composite into the ulna of sheep confirmed that the composite was biocompatible and osteoconductive in vivo, and offered the PAA/HA/CS composite promising material for load-bearing bone substitutes for clinical application. PMID:26635202

  2. Effects of ammonium chloride and sulfate on acid-base status and calcium metabolism of dry Jersey cows.

    PubMed

    Wang, C; Beede, D K

    1992-03-01

    Eight nonlactating, nonpregnant Jersey cows were used in a crossover experiment with two 28-d periods. The control diet consisted of corn silage plus a concentrate mix (68:32, DM basis). The treatment diet was the same, except that NH4Cl and (NH4)2SO4 (98 g of each/d per cow) were added to the concentrate. Cows fed the treatment diet had lower blood pH, higher ionized Ca in blood, and more urinary excretion of Ca, titratable acid, and ammonium than cows fed the control diet. For cows fed the treatment diet, ionized Ca in blood was greater after equal amounts of Na2-EDTA were infused to both treatment groups, and treatment cows recovered faster after infusion of Na2-EDTA was stopped than did control cows. The treatment diet induced mild metabolic acidosis and increased the cows' ability to maintain normal blood Ca concentrations; it potentially could reduce incidence of milk fever.

  3. Acid Sulfate Alteration on Mars

    NASA Technical Reports Server (NTRS)

    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

  4. Sulfate resistance of high calcium fly ash concrete

    NASA Astrophysics Data System (ADS)

    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. Modeling calcium sulfate chemistries with applications to Mars

    NASA Astrophysics Data System (ADS)

    Marion, G. M.; Catling, D. C.; Kargel, J. S.; Crowley, J. K.

    2016-11-01

    On Mars, evidence indicates widespread calcium sulfate minerals. Gypsum (CaSO4ṡ2H2O) seems to be the dominant calcium sulfate mineral in the north polar region of Mars. On the other hand, anhydrite (CaSO4) and bassanite (CaSO4ṡ0.5H2O) appear to be more common in large sedimentary deposits in the lower latitudes. The tropics are generally warmer and drier, and at least locally show evidence of acidic environments in the past. FREZCHEM is a thermodynamic modeling tool used for assessment of equilibrium involving high salinity solutions and salts, designed especially for low temperatures below 298 K (with one version adapted for temperatures up to 373 K), and we have used it to investigate many Earth, Mars, and other planetary science problems. Gypsum and anhydrite were included in earlier versions of FREZCHEM and our model Mars applications, but bassanite (the CaSO4 hemihydrate) has not previously been included. The objectives of this work are to (1) add bassanite to the FREZCHEM model, (2) examine the environments in which thermodynamic equilibrium precipitation of calcium sulfate minerals would be favored on Mars, and (3) use FREZCHEM to model situations where metastable equilibrium might be favored and promote the formation or persistence of one of these phases over the others in violation of an idealized equilibrium state. We added a bassanite equation based on high temperatures (343-373 K). A Mars simulation was based on a previously published Nasbnd Casbnd Mgsbnd Clsbnd SO4 system over the temperature range of 273 to 373 K. With declining temperatures, the first solid phase under equilibrium precipitation is anhydrite at 373 K, then gypsum forms at 319 K (46 °C), and epsomite (MgSO4ṡ7H2O) at 277 K. This sequence could reflect, for example, the precipitation sequence in a saturated solution that is slowly cooled in a deep, warm aquifer. Because FREZCHEM is based on thermodynamic equilibrium, a crude approach to problems involving metastable equilibria is

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

    SciTech Connect

    Dallam, R.D.

    1987-03-23

    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 H/sub 2//sup 35/SO/sub 4/) 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.

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

    PubMed

    Dallam, R D

    1987-03-23

    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 H2 35SO4) 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.

  8. SINTERING AND SULFATION OF CALCIUM SILICATE-ALUMINATE

    EPA Science Inventory

    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...

  9. Sulfation of calcium based sorbents in a combustion environment

    SciTech Connect

    Newton, G.H.

    1987-01-01

    The capture of SO/sub 2/ by dry, calcium-based sorbents was examined in a three part research effort: (1) an experimental evaluation of sorbent materials under isothermal reaction conditions; (2) characterization of sulfation fundamentals through sulfation rate measurements with sized, precalcined sorbents and the development of a distributed pore sulfation model; and (3) experimental definition of reaction temperature effects and computer modeling of the simultaneous sintering and sulfation processes. The experimental sorbent evaluation examined calcitic and dolomitic carbonates and hydrates. High temperature, isothermal SO/sub 2/ capture data were obtained as a function of Ca/S molar ratio, temperature, and SO/sub 2/ concentration for each sorbent. SO/sub 2/ capture was found to be approximately linearly dependent on Ca/S ratio, relatively insensitive to SO/sub 2/ concentration above 2000 ppM, and a strong function of sorbent type. Time resolved sulfation data of sized, precalcined sorbents indicated that sulfation is initially rapid, but beyond approximately 300 ms the sulfation rate decreases dramatically. A distributed pore model, which viewed CaO particles as composed of nonintersecting, cylindrical pores with diameters determined from nitrogen porosimetry, particle boundary layer, pore, and CaSO/sub 4/ product layer diffusions in addition to the heterogeneous chemical reaction was developed. Temperature dependent sulfation data for precalcined sorbents suggest two types of sintering influence particle porosity: sintering associated with the combustion process and sintering promoted by the presence of sulfate ions in the particle crystal structure. Inclusion of both sintering mechanisms in the distributed pore model allowed predictions of the highest temperature experimental data from a variety of precalcines.

  10. The kinetics of sulfation of calcium oxide

    SciTech Connect

    Sarofim, A.F.; Longwell, J.P.

    1989-01-01

    Studies of the sulfation rate behavior show an initial fast rate followed by a rate decrease. This behavior has generally been interpreted as product layer diffusion limitations taking over after an initial kinetic rate regime. Many investigators tried to model this observed rate change, more or less successfully. No agreement has been reached, however, as to the value of the product layer diffusivity. In this work we want to investigate the mechanism of this process. During the last quarter, most attention has been paid to analyzing the results obtained earlier. In the light of some unexpected results, we returned to the most fundamental question: what is the rate-limiting mechanism It appeared that whatever the mechanism is, no rate constant'' could be used, since the rate is a function of the product layer composition, which changes during the reaction. When comparing the results obtained with different samples, however, it appeared that the best correlation was found if one assumes the limiting rate to occur at the CaSO{sub 4} interphase. This point of view has never been presented before and requires therefore a more attentive analysis.

  11. Kinetics of calcium sulfoaluminate formation from tricalcium aluminate, calcium sulfate and calcium oxide

    SciTech Connect

    Li, Xuerun Zhang, Yu; Shen, Xiaodong Wang, Qianqian; Pan, Zhigang

    2014-01-15

    The formation kinetics of tricalcium aluminate (C{sub 3}A) and calcium sulfate yielding calcium sulfoaluminate (C{sub 4}A{sub 3}$) and the decomposition kinetics of calcium sulfoaluminate were investigated by sintering a mixture of synthetic C{sub 3}A and gypsum. The quantitative analysis of the phase composition was performed by X-ray powder diffraction analysis using the Rietveld method. The results showed that the formation reaction 3Ca{sub 3}Al{sub 2}O{sub 6} + CaSO{sub 4} → Ca{sub 4}Al{sub 6}O{sub 12}(SO{sub 4}) + 6CaO was the primary reaction < 1350 °C with and activation energy of 231 ± 42 kJ/mol; while the decomposition reaction 2Ca{sub 4}Al{sub 6}O{sub 12}(SO{sub 4}) + 10CaO → 6Ca{sub 3}Al{sub 2}O{sub 6} + 2SO{sub 2} ↑ + O{sub 2} ↑ primarily occurred beyond 1350 °C with an activation energy of 792 ± 64 kJ/mol. The optimal formation region for C{sub 4}A{sub 3}$ was from 1150 °C to 1350 °C and from 6 h to 1 h, which could provide useful information on the formation of C{sub 4}A{sub 3}$ containing clinkers. The Jander diffusion model was feasible for the formation and decomposition of calcium sulfoaluminate. Ca{sup 2+} and SO{sub 4}{sup 2−} were the diffusive species in both the formation and decomposition reactions. -- Highlights: •Formation and decomposition of calcium sulphoaluminate were studied. •Decomposition of calcium sulphoaluminate combined CaO and yielded C{sub 3}A. •Activation energy for formation was 231 ± 42 kJ/mol. •Activation energy for decomposition was 792 ± 64 kJ/mol. •Both the formation and decomposition were controlled by diffusion.

  12. Tailored Sequential Drug Release from Bilayered Calcium Sulfate Composites

    PubMed Central

    Orellana, Bryan R.; Puleo, David A.

    2014-01-01

    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 poly(lactic-co-glycolic acid) (PLGA) particles embedded in the shell and simvastatin directly loaded into either the shell, core, or both. Microcomputed tomography (MicroCT) images showed the overall layered geometry as well as homogenous 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% per day). 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 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 multiple steps needed to regenerate tissue in infected defects. PMID:25175211

  13. Tailored sequential drug release from bilayered calcium sulfate composites.

    PubMed

    Orellana, Bryan R; Puleo, David A

    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.

  14. Fatty acids on continental sulfate aerosol particles

    NASA Astrophysics Data System (ADS)

    Tervahattu, H.; Juhanoja, J.; Vaida, V.; Tuck, A. F.; Niemi, J. V.; Kupiainen, K.; Kulmala, M.; VehkamäKi, H.

    2005-03-01

    Surface analyses of atmospheric aerosols from different continental sources, such as forest fires and coal and straw burning, show that organic surfactants are found on such aerosols. The predominant organic species detected by time-of-flight secondary ion mass spectrometry on the sulfate aerosols are fatty acids of different carbon chain length up to the C32 acid. These observations are consistent with literature accounts of functional group analysis of bulk samples, but this is the first direct evidence of fatty acid films on the surface of sulfate aerosols. Surface analysis leads to the conclusion that fatty acid films on continental aerosols may be more common than has been previously suggested.

  15. Crystallization of calcium sulfate dihydrate and calcium sulfite hemihydrate from synthetic flue gas desulfurization solutions: Final report

    SciTech Connect

    Trofe, T.W.; Fishman, V.A.; Meserole, F.B.

    1986-10-01

    The precipitation of calcium sulfate dihydrate (CaSO/sub 4/.2H/sub 2/O) and calcium sulfite hemihydrate (CaSO/sub 3/.1/2H/sub 2/O) from high, up to 240,000 mg/L, total dissolved solids (TDS) solutions was studied at 50/sup 0/C. The solutions were selected to cover a range of solution compositions of magnesium, calcium, sodium, chloride, and sulfate. Precipitation rates along with crystal habit and size changes were measured to determine the effects of these dissolved species as compared to dilute solution conditions. Calcium sulfate dihydrate (gypsum) precipitation rate was accelerated in the high TDS solutions, especially those containing chloride ion. Alternatively, calcium sulfite hemihydrate precipitation rate was found to be faster in high sulfate ion containing solutions. Sodium ion appears to produce gypsum crystals more columnar in habit while solutions containing high amounts of calcium produced very lamellar gypsum crystals. Solutions containing magnesium produced acicular gypsum crystals. Calcium sulfite hemihydrate solids precipitated from solutions containing high sulfate concentrations were rod shaped and globular as compared to the lamellar calcium sulfite hemihydrate crystals precipitated from high chloride and dilute solution liquors. Calcium sulfate-calcium sulfite solid solutions were characterized using infrared spectroscopy. Ion scavenging of Na, Mg, and Cl by gypsum and calcium sulfite solids precipitated from these high TDS solutions was also investigated. 10 refs., 21 figs., 13 tabs.

  16. Reduction of orthophosphates loss in agricultural soil by nano calcium sulfate.

    PubMed

    Chen, Dong; Szostak, Paul; Wei, Zongsu; Xiao, Ruiyang

    2016-01-01

    Nutrient loss from soil, especially phosphorous (P) from farmlands to natural water bodies via surface runoff or infiltration, have caused significant eutrophication problems. This is because dissolved orthophosphates are usually the limiting nutrient for algal blooms. Currently, available techniques to control eutrophication are surprisingly scarce. Calcium sulfate or gypsum is a common soil amendment and has a strong complexation to orthophosphates. The results showed that calcium sulfate reduced the amount of water extractable P (WEP) through soil incubation tests, suggesting less P loss from farmlands. A greater decrease in WEP occurred with a greater dosage of calcium sulfate. Compared to conventional coarse calcium sulfate, nano calcium sulfate further reduced WEP by providing a much greater specific surface area, higher solubility, better contact with the fertilizer and the soil particles, and superior dispersibility. The enhancement of the nano calcium sulfate for WEP reduction is more apparent for a pellet- than a powdered- fertilizer. At the dosage of Ca/P weight ratio of 2.8, the WEP decreased by 31±5% with the nano calcium sulfate compared to 20±5% decrease with the coarse calcium sulfate when the pellet fertilizer was used. Computation of the chemical equilibrium speciation shows that calcium hydroxyapatite has the lowest solubility. However, other mineral phases such as hydroxydicalcium phosphate, dicalcium phosphate dihydrate, octacalcium phosphate, and tricalcium phosphate might form preceding to calcium hydroxyapatite. Since calcium sulfate is the major product of the flue gas desulfurization (FGD) process, this study demonstrates a potential beneficial reuse and reduction of the solid FGD waste.

  17. Reduction of orthophosphates loss in agricultural soil by nano calcium sulfate.

    PubMed

    Chen, Dong; Szostak, Paul; Wei, Zongsu; Xiao, Ruiyang

    2016-01-01

    Nutrient loss from soil, especially phosphorous (P) from farmlands to natural water bodies via surface runoff or infiltration, have caused significant eutrophication problems. This is because dissolved orthophosphates are usually the limiting nutrient for algal blooms. Currently, available techniques to control eutrophication are surprisingly scarce. Calcium sulfate or gypsum is a common soil amendment and has a strong complexation to orthophosphates. The results showed that calcium sulfate reduced the amount of water extractable P (WEP) through soil incubation tests, suggesting less P loss from farmlands. A greater decrease in WEP occurred with a greater dosage of calcium sulfate. Compared to conventional coarse calcium sulfate, nano calcium sulfate further reduced WEP by providing a much greater specific surface area, higher solubility, better contact with the fertilizer and the soil particles, and superior dispersibility. The enhancement of the nano calcium sulfate for WEP reduction is more apparent for a pellet- than a powdered- fertilizer. At the dosage of Ca/P weight ratio of 2.8, the WEP decreased by 31±5% with the nano calcium sulfate compared to 20±5% decrease with the coarse calcium sulfate when the pellet fertilizer was used. Computation of the chemical equilibrium speciation shows that calcium hydroxyapatite has the lowest solubility. However, other mineral phases such as hydroxydicalcium phosphate, dicalcium phosphate dihydrate, octacalcium phosphate, and tricalcium phosphate might form preceding to calcium hydroxyapatite. Since calcium sulfate is the major product of the flue gas desulfurization (FGD) process, this study demonstrates a potential beneficial reuse and reduction of the solid FGD waste. PMID:26372940

  18. Electrical conductivity of acidic sulfate solution

    NASA Astrophysics Data System (ADS)

    Majima, Hiroshi; Peters, Ernest; Awakura, Yasuhiro; Park, Sung Kook

    1987-03-01

    The electrical conductivities of the aqueous solution system of H2SO4-MSO4 (involving ZnSO4, MgSO4, Na2SO4, and (NH4)2SO4), reported by Tozawa et al., were examined in terms of a (H2O) and H+ ion concentration. The equations to compute the concentrations of various species in aqueous sulfuric acid solutions containing metal sulfates were derived for a typical example of the H2SO4-ZnSO4-MgSO4-(Na2SO4)-H2O system. It was found that the H+ ion concentrations in concentrated sulfuric acid solutions corresponding to practical zinc electrowinning solutions are very high and remain almost constant with or without the addition of metal sulfates. The addition of metal sulfates to aqueous sulfuric acid solution causes a decrease in electrical conductivity, and this phenomenon is attributed to a decrease in water activity, which reflects a decrease in the amount of free water. The relationship between conductivity and water activity at a constant H+ ion concentration is independent of the kind of sulfates added. On the other hand, any increase in H+ ion concentration results in an increase in electrical conductivity. A novel method for the prediction of electrical conductivity of acidic sulfate solution is proposed that uses the calculated data of water activity and the calculated H+ ion concentration. Also, the authors examined an extension of the Robinson-Bower equation to calculate water activity in quarternary solutions based on molarity instead of molality, and found that such calculated values are in satisfactory agreement with those determined experimentally by a transpiration method.

  19. The electrical properties of calcium sulfate rocks from decametric to micrometric scale

    NASA Astrophysics Data System (ADS)

    Guinea, Ander; Playà, Elisabet; Rivero, Lluís; Ledo, Juan José; Queralt, Pilar

    2012-10-01

    Sulfate rocks have a sedimentary evaporitic origin and are present in many deposits worldwide. Among them, gypsum (dihydrated calcium sulfate) is the most common and is exploited for industrial purposes. Anhydrite (calcium sulfate) is frequently found in gypsum quarries and in non-outcropping sulfates. The greater hardness of anhydrite compared to gypsum causes a problem for gypsum extraction; quarry fronts have to be halted as soon as anhydrite is found. In this work the electrical properties of calcium sulfates have been studied by means of geoelectrical methods. A direct relationship between the electrical conductivity values of the calcium sulfate rocks and their lithological composition has been established with the lutitic matrix being the main controlling factor when it is well connected. When the matrix is under the percolation threshold the sulfate phases are dominant, and the electrical response of the rocks depends on the percentage of each phase. When the rock is matrix dominant, the electrical resistivity trend fits with the Hashin-Shtrikman lower bound for multiphase systems (considering gypsum, anhydrite and matrix as the components). On the other hand, when the rock is calcium sulfate dominant the trend shows the one of the Hashin-Shtrikman upper bound. The reference electrical resistivity value of pure anhydrite rocks has been defined as 104 Ω·m and geoelectrical classification for calcium sulfate rocks has been elaborated. With this classification it is possible to differentiate between calcium sulfate rocks with different composition from their electrical resistivity value. This classification has been checked with field examples and calculating the theoretical resistivity value of thin section photographs with the program ELECFEM2D. The electrical behavior of calcium sulfate rocks is a good reference for other type of rocks with electrically differentiated components, and similar methods can be used to define their geoelectrical responses.

  20. Increased calcium affinity of a fucosylated chondroitin sulfate from sea cucumber.

    PubMed

    Ruggiero, J; Vieira, R P; Mourão, P A

    1994-04-01

    Calcium binding and charge distribution on a fucosylated chondroitin sulfate and a standard chondroitin 6-sulfate have been studied using a metallochromic indicator and conductimetric titrations. The fucosylated chondroitin sulfate has a approximately 5-fold greater affinity for calcium ions than the standard chondroitin 6-sulfate. Possibly, this increased affinity for calcium ions is due to the branches on the fucosylated chondroitin sulfate, since the calcium affinity of an unbranched, sulfated fucan is similar to that of the standard chondroitin 6-sulfate. More charged groups per disaccharide unit (and a shorter distance between these groups) also distinguish the fucosylated chondroitin sulfate from standard chondroitin 6-sulfate. Comparison between native and chemically modified (desulfated or carboxyl-reduced) polysaccharides suggests that the sulfate esters are responsible for the increased charge density of the fucosylated chondroitin sulfate and that the presence of the fucose branches does not alter the length of the repetitive units which compose the central core of chondroitin from sea cucumber. These results are consistent with the chemical studies of these two polysaccharides.

  1. Sulfate and acid resistant concrete and mortar

    DOEpatents

    Liskowitz, J.W.; Wecharatana, M.; Jaturapitakkul, C.; Cerkanowicz, A.E.

    1998-06-30

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction and other applications, which hardenable mixtures demonstrate significant levels of acid and sulfate resistance while maintaining acceptable compressive strength properties. The acid and sulfate hardenable mixtures of the invention containing fly ash comprise cementitious materials and a fine aggregate. The cementitous materials may comprise fly ash as well as cement. The fine aggregate may comprise fly ash as well as sand. The total amount of fly ash in the hardenable mixture ranges from about 60% to about 120% of the total amount of cement, by weight, whether the fly ash is included as a cementious material, fine aggregate, or an additive, or any combination of the foregoing. In specific examples, mortar containing 50% fly ash and 50% cement in cementitious materials demonstrated superior properties of corrosion resistance. 6 figs.

  2. Sulfate and acid resistant concrete and mortar

    DOEpatents

    Liskowitz, John W.; Wecharatana, Methi; Jaturapitakkul, Chai; Cerkanowicz, deceased, Anthony E.

    1998-01-01

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction and other applications, which hardenable mixtures demonstrate significant levels of acid and sulfate resistance while maintaining acceptable compressive strength properties. The acid and sulfate hardenable mixtures of the invention containing fly ash comprise cementitious materials and a fine aggregate. The cementitous materials may comprise fly ash as well as cement. The fine aggregate may comprise fly ash as well as sand. The total amount of fly ash in the hardenable mixture ranges from about 60% to about 120% of the total amount of cement, by weight, whether the fly ash is included as a cementious material, fine aggregate, or an additive, or any combination of the foregoing. In specific examples, mortar containing 50% fly ash and 50% cement in cementitious materials demonstrated superior properties of corrosion resistance.

  3. Acidic sulfate aerosols: characterization and exposure.

    PubMed

    Lioy, P J; Waldman, J M

    1989-02-01

    Exposures to acidic aerosol in the atmosphere are calculated from data reported in the scientific literature. The majority of date was not derived from studies necessarily designed to examine human exposures. Most of the studies were designed to investigate the characteristics of the atmosphere. However, the measurements were useful in defining two potential exposure situations: regional stagnation and transport conditions and local plume impacts. Levels of acidic aerosol in excess of 20 to 40 micrograms/m3 (as H2SO4) have been observed for time durations ranging from 1 to 12 hr. These were associated with high, but not necessarily the highest, atmospheric SO4(2)- levels. Exposures of 100 to 900 micrograms/m3/hr were calculated for the acid events that were monitored. In contrast, earlier London studies indicated that apparent acidity in excess of 100 micrograms/m3 (as H2SO4) was present in the atmosphere, and exposures less than 2000 micrograms/m3/hr were possible. Our present knowledge about the frequency, magnitude, and duration of acidic sulfate aerosol events and episodes is insufficient. Efforts must be made to gather more data, but these should be done in such a way that evaluation of human exposure is the focus of the research. In addition, further data are required on the mechanisms of formation of H2SO4 and on what factors can be used to predict acidic sulfate episodes.

  4. Acidic sulfate aerosols: characterization and exposure.

    PubMed Central

    Lioy, P J; Waldman, J M

    1989-01-01

    Exposures to acidic aerosol in the atmosphere are calculated from data reported in the scientific literature. The majority of date was not derived from studies necessarily designed to examine human exposures. Most of the studies were designed to investigate the characteristics of the atmosphere. However, the measurements were useful in defining two potential exposure situations: regional stagnation and transport conditions and local plume impacts. Levels of acidic aerosol in excess of 20 to 40 micrograms/m3 (as H2SO4) have been observed for time durations ranging from 1 to 12 hr. These were associated with high, but not necessarily the highest, atmospheric SO4(2)- levels. Exposures of 100 to 900 micrograms/m3/hr were calculated for the acid events that were monitored. In contrast, earlier London studies indicated that apparent acidity in excess of 100 micrograms/m3 (as H2SO4) was present in the atmosphere, and exposures less than 2000 micrograms/m3/hr were possible. Our present knowledge about the frequency, magnitude, and duration of acidic sulfate aerosol events and episodes is insufficient. Efforts must be made to gather more data, but these should be done in such a way that evaluation of human exposure is the focus of the research. In addition, further data are required on the mechanisms of formation of H2SO4 and on what factors can be used to predict acidic sulfate episodes. PMID:2651103

  5. Shock-induced devolatilization of calcium sulfate and implications for K-T extinctions

    NASA Technical Reports Server (NTRS)

    Chen, Guangqing; Tyburczy, James A.; Ahrens, Thomas J.

    1994-01-01

    The devolatilization of calcium sulfate, which is present in the target rock of the Chicxulub, Mexico impact structure, and dispersal in the stratosphere of the resultant sulfuric acid aerosol have been suggested as a possible mechanism for the Cretaceous-Tertiary extinctions. We measured the amount of SO2 produced from two shock-induced devolatilization reactions of calcium sulfate up to 42 GPa in the laboratory. We found both to proceed to a much lower extent than calculated by equilibrium thermodynamic calculations. Reaction products are found to be approx. 10(exp -2) times those calculated for equilibrium. Upon modeling the quantity of sulfur oxides degassed into the atmosphere from shock devolatilization of CaSO4 in the Chicxulub lithographic section, the resulting 9 x 10(exp 16) to 6 x 10(exp 17) g (in sulfur mass) is lower by a factor of 10-100 than previous upper limit estimates, the related environmental stress arising from the resultant global cooling and fallout of acid rain is insufficient to explain the widespread K-T extinctions.

  6. Shock-induced devolatization of calcium sulfate and implications for K-T extinctions

    NASA Technical Reports Server (NTRS)

    Chen, Guangqing; Tyburczy, James A.; Ahrens, Thomas J.

    1993-01-01

    Calcium sulfate devolatization during the impact at Chicxulub, Mexico and dispersal in the stratosphere of the resultant sulfuric acid aerosol have been suggested as a possible mechanism for the Cretaceous-Tertiary extinctions. In this paper, we investigated two shock-induced devolatization reactions of calcium sulfate up to 42 GPa in the laboratory: CaSO4 + SiO2 yields CaSiO3 + SO3(degassed) and CaSO4 yields CaO + SO2(degassed) + 1/2 O2(degassed). We found both to proceed to a much less extent than calculated by equilibrium thermodynamic calculations. Reaction products are found to be 10(exp -2) times those calculated for equilibrium. Consequently our estimate of the amount of sulfur oxides degassed into the atmosphere from shock devolatization of CaS04 in the Chicxulub lithographic section (6x10(exp 15)-2x10(exp 16)g in sulfur mass) is lower by a factor of 70 to 400 than previous estimates; the related environmental stress arising from the resultant global cooling of approximately 4 K and fallout of acid rain does not appear to suffice to explain the widespread K-T extinctions.

  7. Acid Sulfate Alteration in Gusev Crater, Mars

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

    dust. The Moessbauer parameters are not definitive for mineralogical speciation (other than octahedrally-coordinated Fe(3+) but are consistent with a schwertmannite-like phase (i.e., a nanophase ferric oxide). The high oxidation state and values of Moessbauer parameters (center shift and quadrupole splitting) for the high-SO3 samples imply ferric sulfate (i.e., oxidized sulfur), although the hydration state cannot be constrained. In no case is there an excess of SO3 over available cations (i.e., no evidence for elemental sulfur), and Fe sulfide (pyrite) has been detected in only one Gusev sample. The presence of both high-SiO2 (and low total iron and SO3) and high SO3 (and high total iron as ferric sulfate) can be accommodated by a two-step geochemical model developed with the Geochemist's Workbench. (1) Step 1 is anoxic acid sulfate leaching of Martian basalt at high water-to rock ratios (greater than 70). The result is a high-SiO2 residue0, and anoxic conditions are required to solubilize Fe as Fe(2+). (2) Step 2 is the oxic precipitation of sulfate salts from the leachate. Oxic conditions are required to produce the high concentrations of ferric sulfate with minor Mg-sulfates and no detectable Fe(2+)-sulfates.

  8. Acidic sulfate aerosols: characterization and exposure

    SciTech Connect

    Lioy, P.J.; Waldman, J.M.

    1989-02-01

    Exposures to acidic aerosol in the atmosphere are calculated from data reported in the scientific literature. The majority of date was not derived from studies necessarily designed to examine human exposures. Most of the studies were designed to investigate the characteristics of the atmosphere. However, the measurements were useful in defining two potential exposure situations: regional stagnation and transport conditions and local plume impacts. Levels of acidicaerosol in excess of 20 to 40 micrograms/m/sup 3/ (as H/sub 2/SO/sub 4/) have been observed for time durations ranging from 1 to 12 hr. These were associated with high, but not necessarily the highest, atmospheric SO/sub 4/(2)- levels. Exposures of 100 to 900 micrograms/m/sup 3//hr were calculated for the acid events that were monitored. In contrast, earlier London studies indicated that apparent acidity in excess of 100 micrograms/m/sup 3/ (as H/sub 2/SO/sub 4/) was present in the atmosphere, and exposures less than 2000 micrograms/m/sup 3//hr were possible. Our present knowledge about the frequency, magnitude, and duration of acidic sulfate aerosol events and episodes is insufficient. Efforts must be made to gather more data, but these should be done in such a way that evaluation of human exposure is the focus of the research. In addition, further data are required on the mechanisms of formation of H/sub 2/SO/sub 4/ and on what factors can be used to predict acidic sulfate episodes. 96 references.

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

    PubMed

    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.

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

    PubMed

    de Jonge, H J M Henk-Marijn; Gans, R O B Rijk; Huls, Gerwin

    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 absorption. No convincing scientific evidence supporting the advice to prescribe calcium citrate instead of calcium carbonate to patients who also take antacids is available, and therefore deserves further investigation. On the contrary, the fact that calcium carbonate does not need acid in order to be absorbed, has also not been proven. In clinical practise, it appears important that calcium is taken with meals in order to improve its absorption. PMID:22914054

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

    PubMed

    de Jonge, H J M Henk-Marijn; Gans, R O B Rijk; Huls, Gerwin

    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 absorption. No convincing scientific evidence supporting the advice to prescribe calcium citrate instead of calcium carbonate to patients who also take antacids is available, and therefore deserves further investigation. On the contrary, the fact that calcium carbonate does not need acid in order to be absorbed, has also not been proven. In clinical practise, it appears important that calcium is taken with meals in order to improve its absorption.

  12. Calcium binding to an aquatic fulvic acid

    NASA Astrophysics Data System (ADS)

    Paxéus, Nicklas; Wedborg, Margareta

    The degree of binding of calcium to aquatic fulvic acid from the Göta River was estimated from potentiometric titrations. A pH-glass electrode and a calcium-selective electrode were used to monitor the free concentrations of the competing, central ions. The ionic strength and the temperature were maintained constant at 0.1 M and 25°C. The total concentration of fulvic acid was maintained at approximately 1 g 1-1, while the total calcium concentration was varied within the range 0-10-3 M. Two types of titrations were carried out: (1) back titration with hydrochloric acid from basic solution, roughly within the pH range 10.5-2.5; (2) titration with calcium chloride at a constant total hydrogen ion concentration. The model applied for the calcium binding was an extension of our previous model for the acid-base behaviour.

  13. Structure, properties and animal study of a calcium phosphate/calcium sulfate composite cement.

    PubMed

    Chen, Wei-Luen; Chen, Chang-Keng; Lee, Jing-Wei; Lee, Yu-Ling; Ju, Chien-Ping; Lin, Jiin-Huey Chern

    2014-04-01

    In-vitro and in-vivo studies have been conducted on an in-house-developed tetracalcium phosphate (TTCP)/dicalcium phosphate anhydrous (DCPA)/calcium sulfate hemihydrate (CSH)-derived composite cement. Unlike most commercial calcium-based cement pastes, the investigated cement paste can be directly injected into water and harden without dispersion. The viability value of cells incubated with a conditioned medium of cement extraction is >90% that of Al2O3 control and >80% that of blank medium. Histological examination reveals excellent bonding between host bone and cement without interposition of fibrous tissues. At 12 weeks-post implantation, significant remodeling activities are found and a new bone network is developed within the femoral defect. The 26-week samples show that the newly formed bone becomes more mature, while the interface between residual cement and the new bone appears less identifiable. Image analysis indicates that the resorption rate of the present cement is much higher than that of TTCP or TTCP/DCPA-derived cement under similar implantation conditions.

  14. EVALUATION OF SURGICAL CAVITIES FILLED WITH THREE TYPES OF CALCIUM SULFATE

    PubMed Central

    Maeda, Sergio Toshinori; Bramante, Clovis Monteiro; Taga, Rumio; Garcia, Roberto Brandão; de Moraes, Ivaldo Gomes; Bernadineli, Norberti

    2007-01-01

    The aim of this study was to evaluate histologically, three types of calcium sulfate - Merck (Brazil), Surgiplaster (Italy) and Capset (USA) - in surgically created defects on rabbit femurs. Twenty male New Zealand rabbits were used. Two surgical bone defects (5 mm diameter x 8 mm depth) were created on each distal epiphysis using a #3 Dentoflex trephine bur. Defects were filled with: group 1 - di-hydrated calcium sulfate (Merck); group 2 - Capset (Lifecore-USA); group 3 - Surgiplaster (Classimport-Italy); group 4 – control (blood clot). The animals were sacrificed 30, 60, 90 and 180 days postoperatively. Semi-serial 6-mm-thick sections were obtained, stained with hematoxylin and eosin and examined under light microscopy. Bone defects treated with calcium sulfate exhibited new bone formation regardless of the product trademark. PMID:19089171

  15. Biological functions of iduronic acid in chondroitin/dermatan sulfate

    PubMed Central

    Thelin, Martin A; Bartolini, Barbara; Axelsson, Jakob; Gustafsson, Renata; Tykesson, Emil; Pera, Edgar; Oldberg, Åke; Maccarana, Marco; Malmstrom, Anders

    2013-01-01

    The presence of iduronic acid in chondroitin/dermatan sulfate changes the properties of the polysaccharides because it generates a more flexible chain with increased binding potentials. Iduronic acid in chondroitin/dermatan sulfate influences multiple cellular properties, such as migration, proliferation, differentiation, angiogenesis and the regulation of cytokine/growth factor activities. Under pathological conditions such as wound healing, inflammation and cancer, iduronic acid has diverse regulatory functions. Iduronic acid is formed by two epimerases (i.e. dermatan sulfate epimerase 1 and 2) that have different tissue distribution and properties. The role of iduronic acid in chondroitin/dermatan sulfate is highlighted by the vast changes in connective tissue features in patients with a new type of Ehler–Danlos syndrome: adducted thumb-clubfoot syndrome. Future research aims to understand the roles of the two epimerases and their interplay with the sulfotransferases involved in chondroitin sulfate/dermatan sulfate biosynthesis. Furthermore, a better definition of chondroitin/dermatan sulfate functions using different knockout models is needed. In this review, we focus on the two enzymes responsible for iduronic acid formation, as well as the role of iduronic acid in health and disease. PMID:23441919

  16. In vitro degradability, bioactivity and primary cell responses to bone cements containing mesoporous magnesium-calcium silicate and calcium sulfate for bone regeneration.

    PubMed

    Ding, Yueting; Tang, Songchao; Yu, Baoqing; Yan, Yonggang; Li, Hong; Wei, Jie; Su, Jiacan

    2015-10-01

    Mesoporous calcium sulfate-based bone cements (m-CSBC) were prepared by introducing mesoporous magnesium-calcium silicate (m-MCS) with specific surface area (410.9 m² g(-1)) and pore volume (0.8 cm³ g(-1)) into calcium sulfate hemihydrate (CSH). The setting time of the m-CSBC was longer with the increase of m-MCS content while compressive strength decreased. The degradation ratio of m-CSBC increased from 48.6 w% to 63.5 w% with an increase of m-MCS content after soaking in Tris-HCl solution for 84 days. Moreover, the m-CSBC containing m-MCS showed the ability to neutralize the acidic degradation products of calcium sulfate and prevent the pH from dropping. The apatite could be induced on m-CSBC surfaces after soaking in SBF for 7 days, indicating good bioactivity. The effects of the m-CSBC on vitamin D3 sustained release behaviours were investigated. It was found that the cumulative release ratio of vitamin D3 from the m-CSBC significantly increased with the increase of m-MCS content after soaking in PBS (pH = 7.4) for 25 days. The m-CSBC markedly improved the cell-positive responses, including the attachment, proliferation and differentiation of MC3T3-E1 cells, suggesting good cytocompatibility. Briefly, m-CSBC with good bioactivity, degradability and cytocompatibility might be an excellent biocement for bone regeneration.

  17. In vitro degradability, bioactivity and primary cell responses to bone cements containing mesoporous magnesium–calcium silicate and calcium sulfate for bone regeneration

    PubMed Central

    Ding, Yueting; Tang, Songchao; Yu, Baoqing; Yan, Yonggang; Li, Hong; Wei, Jie; Su, Jiacan

    2015-01-01

    Mesoporous calcium sulfate-based bone cements (m-CSBC) were prepared by introducing mesoporous magnesium–calcium silicate (m-MCS) with specific surface area (410.9 m² g−1) and pore volume (0.8 cm³ g−1) into calcium sulfate hemihydrate (CSH). The setting time of the m-CSBC was longer with the increase of m-MCS content while compressive strength decreased. The degradation ratio of m-CSBC increased from 48.6 w% to 63.5 w% with an increase of m-MCS content after soaking in Tris–HCl solution for 84 days. Moreover, the m-CSBC containing m-MCS showed the ability to neutralize the acidic degradation products of calcium sulfate and prevent the pH from dropping. The apatite could be induced on m-CSBC surfaces after soaking in SBF for 7 days, indicating good bioactivity. The effects of the m-CSBC on vitamin D3 sustained release behaviours were investigated. It was found that the cumulative release ratio of vitamin D3 from the m-CSBC significantly increased with the increase of m-MCS content after soaking in PBS (pH = 7.4) for 25 days. The m-CSBC markedly improved the cell-positive responses, including the attachment, proliferation and differentiation of MC3T3-E1 cells, suggesting good cytocompatibility. Briefly, m-CSBC with good bioactivity, degradability and cytocompatibility might be an excellent biocement for bone regeneration. PMID:26423442

  18. In vitro degradability, bioactivity and primary cell responses to bone cements containing mesoporous magnesium-calcium silicate and calcium sulfate for bone regeneration.

    PubMed

    Ding, Yueting; Tang, Songchao; Yu, Baoqing; Yan, Yonggang; Li, Hong; Wei, Jie; Su, Jiacan

    2015-10-01

    Mesoporous calcium sulfate-based bone cements (m-CSBC) were prepared by introducing mesoporous magnesium-calcium silicate (m-MCS) with specific surface area (410.9 m² g(-1)) and pore volume (0.8 cm³ g(-1)) into calcium sulfate hemihydrate (CSH). The setting time of the m-CSBC was longer with the increase of m-MCS content while compressive strength decreased. The degradation ratio of m-CSBC increased from 48.6 w% to 63.5 w% with an increase of m-MCS content after soaking in Tris-HCl solution for 84 days. Moreover, the m-CSBC containing m-MCS showed the ability to neutralize the acidic degradation products of calcium sulfate and prevent the pH from dropping. The apatite could be induced on m-CSBC surfaces after soaking in SBF for 7 days, indicating good bioactivity. The effects of the m-CSBC on vitamin D3 sustained release behaviours were investigated. It was found that the cumulative release ratio of vitamin D3 from the m-CSBC significantly increased with the increase of m-MCS content after soaking in PBS (pH = 7.4) for 25 days. The m-CSBC markedly improved the cell-positive responses, including the attachment, proliferation and differentiation of MC3T3-E1 cells, suggesting good cytocompatibility. Briefly, m-CSBC with good bioactivity, degradability and cytocompatibility might be an excellent biocement for bone regeneration. PMID:26423442

  19. Acidity characterization of a titanium and sulfate modified vermiculite

    SciTech Connect

    Hernandez, W.Y.; Centeno, M.A.; Odriozola, J.A.; Moreno, S.; Molina, R.

    2008-07-01

    A natural vermiculite has been modified with titanium and sulfated by the intercalation and impregnation method in order to optimize the acidity of the clay mineral, and characterization of samples were analyzed by X-ray fluorescence (XRF), X-ray diffraction (XRD), nitrogen adsorption isotherms, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and temperature programmed desorption with ammonia (TPD-NH{sub 3}). All the modified solids have a significantly higher number of acidic sites with respect to the parent material and in all of these, Broensted as well as Lewis acidity are identified. The presence of sulfate appears not to increase the number of acidic centers in the modified clay. For the materials sulfated with the intercalation method, it is observed that the strength of the acidic sites found in the material increases with the nominal sulfate/metal ratio. Nevertheless, when elevated quantities of sulfur are deposited, diffusion problems in the heptane reaction appear.

  20. HIGH-TEMPERATURE, SHORT-TIME SULFATION OF CALCIUM- BASED SORBENTS. 1. THEORETICAL SULFATION MODEL

    EPA Science Inventory

    A mathematical model for the sulfation of CaO is developed around the overlapping grain concept. The potential influence of high mass-transfer rates from simultaneous calcination of CaCO3 or Ca(OH)2 is incorporated in the mass-transfer coefficient for SO2 diffusion to the partic...

  1. Dissolution kinetics of polycrystalline calcium sulfate-based materials: influence of chemical modification.

    PubMed

    Fisher, Robin D; Mbogoro, Michael M; Snowden, Michael E; Joseph, Maxim B; Covington, James A; Unwin, Patrick R; Walton, Richard I

    2011-09-01

    Using a channel flow cell (CFC) system, the dissolution kinetics of polycrystalline gypsum-based materials have been examined with the aim of understanding their interaction with water, a property that limits the applications of the material in many situations. ICP (inductively coupled plasma) analysis of elemental concentrations in solution as a function of time yields surface fluxes by using a finite element modeling approach to simulate the hydrodynamic behavior within the CFC. After correction for surface roughness, a value for the intrinsic dissolution flux into water of pure polycrystalline gypsum, CaSO(4).2H(2)O, of 1.1 (±0.4) × 10(-8) mol cm(-2) s(-1) has been obtained. The addition of known humid creep inhibitors to the gypsum samples, including boric acid, tartaric acid and 3,4,5-trihydroxybenzoic acid (gallic acid), was found to have little measurable effect on the dissolution kinetics of gypsum: all yielded dissolution fluxes of 1.4 (±0.6) × 10(-8) mol cm(-2) s(-1). However, trisodium trimetaphosphate (STMP) was found to have a small detectable inhibitory effect relative to pure gypsum yielding a flux of 7.4 (±2.0) × 10(-9) mol cm(-2) s(-1). The data strongly suggest that models for humid creep inhibition that involve dissolution-crystallization of gypsum crystallites are less likely than those that involve a hindered ingress of water into the gypsum matrix. For comparison, composite materials that comprised of calcium sulfate anhydrite (CaSO(4)) crystallites bound by a polyphosphate matrix were also studied. For some of these samples, Ca(2+) surface fluxes were observed to be ∼1 order of magnitude lower than values for polycrystalline gypsum control substrates, suggesting a useful way to impart water resistance to gypsum-based materials. PMID:21861513

  2. Dissolution kinetics of polycrystalline calcium sulfate-based materials: influence of chemical modification.

    PubMed

    Fisher, Robin D; Mbogoro, Michael M; Snowden, Michael E; Joseph, Maxim B; Covington, James A; Unwin, Patrick R; Walton, Richard I

    2011-09-01

    Using a channel flow cell (CFC) system, the dissolution kinetics of polycrystalline gypsum-based materials have been examined with the aim of understanding their interaction with water, a property that limits the applications of the material in many situations. ICP (inductively coupled plasma) analysis of elemental concentrations in solution as a function of time yields surface fluxes by using a finite element modeling approach to simulate the hydrodynamic behavior within the CFC. After correction for surface roughness, a value for the intrinsic dissolution flux into water of pure polycrystalline gypsum, CaSO(4).2H(2)O, of 1.1 (±0.4) × 10(-8) mol cm(-2) s(-1) has been obtained. The addition of known humid creep inhibitors to the gypsum samples, including boric acid, tartaric acid and 3,4,5-trihydroxybenzoic acid (gallic acid), was found to have little measurable effect on the dissolution kinetics of gypsum: all yielded dissolution fluxes of 1.4 (±0.6) × 10(-8) mol cm(-2) s(-1). However, trisodium trimetaphosphate (STMP) was found to have a small detectable inhibitory effect relative to pure gypsum yielding a flux of 7.4 (±2.0) × 10(-9) mol cm(-2) s(-1). The data strongly suggest that models for humid creep inhibition that involve dissolution-crystallization of gypsum crystallites are less likely than those that involve a hindered ingress of water into the gypsum matrix. For comparison, composite materials that comprised of calcium sulfate anhydrite (CaSO(4)) crystallites bound by a polyphosphate matrix were also studied. For some of these samples, Ca(2+) surface fluxes were observed to be ∼1 order of magnitude lower than values for polycrystalline gypsum control substrates, suggesting a useful way to impart water resistance to gypsum-based materials.

  3. Total sulfate vs. sulfuric acid monomer concenterations in nucleation studies

    NASA Astrophysics Data System (ADS)

    Neitola, K.; Brus, D.; Makkonen, U.; Sipilä, M.; Mauldin, R. L., III; Sarnela, N.; Jokinen, T.; Lihavainen, H.; Kulmala, M.

    2015-03-01

    Sulfuric acid is known to be a key component for atmospheric nucleation. Precise determination of sulfuric-acid concentration is a crucial factor for prediction of nucleation rates and subsequent growth. In our study, we have noticed a substantial discrepancy between sulfuric-acid monomer concentrations and total-sulfate concentrations measured from the same source of sulfuric-acid vapor. The discrepancy of about 1-2 orders of magnitude was found with similar particle-formation rates. To investigate this discrepancy, and its effect on nucleation, a method of thermally controlled saturator filled with pure sulfuric acid (97% wt.) for production of sulfuric-acid vapor is applied and rigorously tested. The saturator provided an independent vapor-production method, compared to our previous method of the furnace (Brus et al., 2010, 2011), to find out if the discrepancy is caused by the production method itself. The saturator was used in a H2SO4-H2O nucleation experiment, using a laminar flow tube to check reproducibility of the nucleation results with the saturator method, compared to the furnace. Two independent methods of mass spectrometry and online ion chromatography were used for detecting sulfuric-acid or sulfate concentrations. Measured sulfuric-acid or total-sulfate concentrations are compared to theoretical predictions calculated using vapor pressure and a mixing law. The calculated prediction of sulfuric-acid concentrations agrees very well with the measured values when total sulfate is considered. Sulfuric-acid monomer concentration was found to be about 2 orders of magnitude lower than theoretical predictions, but with a temperature dependency similar to the predictions and the results obtained with the ion-chromatograph method. Formation rates are reproducible when compared to our previous results with both sulfuric-acid or total-sulfate detection and sulfuric-acid production methods separately, removing any doubts that the vapor-production method would

  4. Experimental study of acid-sulfate alteration of basalt and implications for sulfate deposits on Mars

    NASA Astrophysics Data System (ADS)

    McCollom, Thomas M.; Robbins, Mark; Moskowitz, Bruce; Berquó, Thelma S.; Jöns, Niels; Hynek, Brian M.

    2013-04-01

    Acid-sulfate alteration of basalt by SO2-bearing volcanic vapors has been proposed as one possible origin for sulfate-rich deposits on Mars. To better define mineralogical signatures of acid-sulfate alteration, laboratory experiments were performed to investigate alteration pathways and geochemical processes during reaction of basalt with sulfuric acid. Pyroclastic cinders composed of phenocrysts including plagioclase, olivine, and augite embedded in glass were reacted with sulfuric acid at 145 °C for up to 137 days at a range of fluid : rock ratios. During the experiments, the phenocrysts reacted rapidly to form secondary products, while the glass was unreactive. Major products included amorphous silica, anhydrite, and Fe-rich natroalunite, along with minor iron oxides/oxyhydroxides (probably hematite) and trace levels of other sulfates. At the lowest fluid : rock ratio, hexahydrite and an unidentified Fe-silicate phase also occurred as major products. Reaction-path models indicated that formation of the products required both slow dissolution of glass and kinetic inhibitions to precipitation of a number of minerals including phyllosilicates and other aluminosilicates as well as Al- and Fe-oxides/oxyhydroxides. Similar models performed for Martian basalt compositions predict that the initial stages of acid-sulfate alteration of pyroclastic deposits on Mars should result in formation of amorphous silica, anhydrite, Fe-bearing natroalunite, and kieserite, along with relict basaltic glass. In addition, analysis of the experimental products indicates that Fe-bearing natroalunite produces a Mössbauer spectrum closely resembling that of jarosite, suggesting that it should be considered an alternative to the component in sulfate-rich bedrocks at Meridiani Planum that has previously been identified as jarosite.

  5. Remediation of Acid Mine Drainage with Sulfate Reducing Bacteria

    ERIC Educational Resources Information Center

    Hauri, James F.; Schaider, Laurel A.

    2009-01-01

    Sulfate reducing bacteria have been shown to be effective at treating acid mine drainage through sulfide production and subsequent precipitation of metal sulfides. In this laboratory experiment for undergraduate environmental chemistry courses, students design and implement a set of bioreactors to remediate acid mine drainage and explain observed…

  6. Sulfated phenolic acids from Dasycladales siphonous green algae.

    PubMed

    Kurth, Caroline; Welling, Matthew; Pohnert, Georg

    2015-09-01

    Sulfated aromatic acids play a central role as mediators of chemical interactions and physiological processes in marine algae and seagrass. Among others, Dasycladus vermicularis (Scopoli) Krasser 1898 uses a sulfated hydroxylated coumarin derivative as storage metabolite for a protein cross linker that can be activated upon mechanical disruption of the alga. We introduce a comprehensive monitoring technique for sulfated metabolites based on fragmentation patterns in liquid chromatography/mass spectrometry and applied it to Dasycladales. This allowed the identification of two new aromatic sulfate esters 4-(sulfooxy)phenylacetic acid and 4-(sulfooxy)benzoic acid. The two metabolites were synthesized to prove the mass spectrometry-based structure elucidation in co-injections. We show that both metabolites are transformed to the corresponding desulfated phenols by sulfatases of bacteria. In biofouling experiments with Escherichia coli and Vibrio natriegens the desulfated forms were more active than the sulfated ones. Sulfatation might thus represent a measure of detoxification that enables the algae to store inactive forms of metabolites that are activated by settling organisms and then act as defense. PMID:26188914

  7. Experimental Comparison of Calcium Sulfate (CaSO(4)) Scale Deposition on Coated Carbon Steel and Titanium Surfaces

    NASA Astrophysics Data System (ADS)

    Al-Otaibi, Dhawi AbdulRahman

    Calcium Sulfate (CaSO4) deposit reduces heat exchange in heat transfer equipment which adversely affects the equipment performance and plant production. This experimental study was conducted by using the Rotating Cylinder Electrode (RCE) equipment available in the university's Center for Engineering Research (CER/RI) to study and compare the effect of solution hydrodynamics on Calcium Sulfate (CaSO4) scale deposition on coated carbon steel and titanium surfaces. In addition, the Scanning Electron Microscopic was used to examine the morphology and distribution of Calcium Sulfate (CaSO 4) crystals deposited on titanium metal surfaces. In this study, the rotational speed was varied from 100 to 2000 RPM to study the behavior of Calcium Sulfate (CaSO4) accumulation on both materials. Based on the experimental results, Calcium Sulfate (CaSO4) scale obtained in the present study was almost constant on coated carbon steel in which the rate of scale deposition is equal to the rate of scale removal. However, the deposition of Calcium Sulfate (CaSO4) observed on titanium material was increased as the speed increased.

  8. Remediation of acid mine drainage with sulfate reducing bacteria

    SciTech Connect

    Hauri, J.F.; Schaider, L.A.

    2009-02-15

    Sulfate reducing bacteria have been shown to be effective at treating acid mine drainage through sulfide production and subsequent precipitation of metal sulfides. In this laboratory experiment for undergraduate environmental chemistry courses, students design and implement a set of bioreactors to remediate acid mine drainage and explain observed changes in dissolved metal concentrations and pH. Using synthetic acid mine drainage and combinations of inputs, students monitor their bioreactors for decreases in dissolved copper and iron concentrations.

  9. [Influences of magnesium sulfate on maternal calcium metabolism in preterm labor].

    PubMed

    Takeuchi, K; Inui, M; Mori, T

    1992-11-01

    The effects of intravenous magnesium sulfate tocolysis on calcium metabolism were studied in 10 patients with preterm labor. A loading dose of magnesium sulfate (4g) was administered intravenously maintenance intravenous infusion of magnesium sulfate (1g per hour). All patients simultaneously received 50 micrograms ritodrin per minutes by intravenous infusion. Serum magnesium increased from 1.91 +/- 0.06mg/dl to 4.6 +/- 0.71mg/dl at 30 minutes (p < 0.01) and it remained relatively high. The fall in serum calcium corrected by serum total protein was most rapid during the first 30 minutes, from 9.04 +/- 0.47mg/dl to 8.3 +/- 0.27mg/dl (p < 0.01). Urinary excretion of magnesium, represented as the calcium/creatinine ratio, rose markedly from 0.05 +/- 0.01 to 3.18 +/- 0.8 at an hour (p < 0.01) and thereafter remained higher than the baseline level. Changes in urinary excretion of calcium paralleled those of urinary evcretion of magnesium. Serum parathyroid hormone rose from 118 +/- 42.2pg/ml to 294 +/- 121pg/ml at 6 hours (p < 0.05). Serum 1 alpha,25-(OH)2D3-rose from 89.3 +/- 44.2pg/ml to 126 +/- 38.7pg/ml (p < 0.05). Serum calcitonin showed no significant change. These findings indicate that correction of hypocalcemia mainly depends on secretion of parathyroid hormone in the early stage, and thereafter depends on the cooperative action of parathyroid hormone and 1 alpha,25-(OH)2D3. PMID:1460364

  10. Ambient aerosols remain highly acidic despite dramatic sulfate reductions

    NASA Astrophysics Data System (ADS)

    Nenes, Athanasios; Weber, Rodney; Guo, Hongyu; Russell, Armistead

    2016-04-01

    The pH of fine particles has many vital environmental impacts. By affecting aerosol concentrations, chemical composition and toxicity, particle pH is linked to regional air quality and climate, and adverse effects on human health. Sulfate is often the main acid component that drives pH of fine particles (i.e., PM2.5) and is neutralized to varying degrees by gas phase ammonia. Sulfate levels have decreased by approximately 70% over the Southeastern United States in the last fifteen years, but measured ammonia levels have been fairly steady implying the aerosol may becoming more neutral. Using a chemically comprehensive data set, combined with a thermodynamic analysis, we show that PM2.5 in the Southeastern U.S. is highly acidic (pH between 0 and 2), and that pH has remained relatively unchanged throughout the past decade and a half of decreasing sulfate. Even with further sulfate reductions, pH buffering by gas-particle partitioning of ammonia is expected to continue until sulfate drops to near background levels, indicating that fine particle pH will remain near current levels into the future. These results are non-intuitive and reshape expectations of how sulfur emission reductions impact air quality in the Southeastern U.S. and possibly other regions across the globe.

  11. Local Release of Antibiotics for Surgical Site Infection Management Using High-Purity Calcium Sulfate: An In Vitro Elution Study

    PubMed Central

    Cooper, John J.; Florance, Hannah; Robinson, Matthew T.; Michell, Stephen

    2015-01-01

    Abstract Background: The aim of this study was to characterize the elution of four antibiotics from pharmaceutical-grade calcium sulfate beads and show that the eluted antibiotics retained efficacy. Methods: Calcium sulfate was combined with gentamicin, tobramycin, vancomycin, or rifampicin (ratio: 20 g of calcium sulfate, to 240 mg, 500 mg, 900 mg, and 600 mg of antibiotic, respectively). Three grams of beads were immersed in 4 mL of sterile phosphate-buffered saline (PBS) at 37°C. At each time point (4, 8, 24 h; 2, 7, 14, 28, 42 d), eluates were removed for analysis by liquid chromatography–mass spectrometry. The antimicrobial efficacy of antibiotics combined with calcium sulfate beads after 42 d was tested by a modified Kirby-Bauer disc diffusion assay. Results: All samples showed a generally exponential decay in the eluted antibiotic concentration. At the first time point, both gentamicin and tobramycin had eluted to a peak concentration of approximately 10,000 mcg/mL. For rifampicin, the peak concentration occurred at 24 h, whereas for vancomycin, it occurred at 48 h. The eluted concentrations exceeded the minimum inhibitory concentration for common periprosthetic joint infection pathogens for the entire span of the 42 study days. Mass spectrometry confirmed all antibiotics were unchanged when eluted from the calcium sulfate carrier. Antimicrobial efficacy was unaltered after 42 d in combination with calcium sulfate at 37°C. Conclusions: Pharmaceutical-grade calcium sulfate has the potential for targeted local release of tobramycin, gentamicin, vancomycin, and rifampicin over a clinically meaningful time period. PMID:25148101

  12. Mixed metal phospho-sulfates for acid catalysis

    SciTech Connect

    Thoma, S.G.; Jackson, N.B.; Nenoff, T.M.; Maxwell, R.S.

    1997-12-01

    Mixed metal phospho-sulfates have been prepared and evaluated for use as acid catalysts via 2-methyl-2-pentene isomerization and o-xylene isomerization. Particular members of this class of materials exhibit greater levels of activity than sulfated zirconia as well as lower rates and magnitudes of deactivation. {sup 31}P MAS NMR has been used to examine the role of phosphorus in contributing to the activity and deactivation behavior of these materials, while powder x-ray diffraction, BET surface area, IR, and elemental analysis were used to characterize the bulk catalysts.

  13. Reactions of calcium orthosilicate and barium zirconate with oxides and sulfates of various elements

    NASA Technical Reports Server (NTRS)

    Zaplatynsky, I.

    1979-01-01

    Calcium orthosilicate and barium zirconate were evaluated as the insulation layer of thermal barrier coatings for air cooled gas turbine components. Their reactions with various oxides and sulfates were studied at 1100 C and 1300 C for times ranging up to 400 and 200 hours, respectively. These oxides and sulfates represent potential impurities or additives in gas turbine fuels and in turbine combustion air, as well as elements of potential bond coat alloys. The phase compositions of the reaction products were determined by X-ray diffraction analysis. BaZrO3 and 2CaO-SiO2 both reacted with P2O5, V2O5, Cr2O3, Al2O3, and SiO2. In addition, 2CaO-SiO2 reacted with Na2O, BaO, MgO, and CoO and BaZrO3 reacted with Fe2O3.

  14. Production development and utilization of Zimmer Station wet FGD by-products. Final report. Volume 4, A laboratory study conducted in fulfillment of Phase 2, Objective 1 titled. Inhibition of acid production in coal refuse amended with calcium sulfite and calcium sulfate - containing FGD solids

    SciTech Connect

    Hao, Y. L.; Dick, W. A.; Stehouwer, R. C.; Bigham, J. M.

    1998-06-30

    Control of S02 emission from coal combustion requires desulfurization of coal before its combustion to produce coal refuse. Alternatively, gaseous emissions from coal combustion may be scrubbed to yield flue gas desulfurization (FGD) by-products that include calcium sulfite (CaSO3∙0.5H2O or simply CaS03). Acid production in coal refuse due to pyrite oxidation and disposal of large amounts of FGD can cause environmental degradation. Addition of CaS03 and CaS03-containing FGD to coal refuse may reduce the amounts of oxygen and ferric ion available to oxidize pyrite because the sulfite moiety in CaS03 is a strong reductant and thus may mitigate acid production in coal refuse. In Chapter 1, it was shown that CaS03 efficiently scavenged dissolved oxygen and ferric ion in water under the conditions commonly encountered in a coal refuse disposal environment. In the presence ofCaS03, the concentration of dissolved oxygen in water exposed to the atmosphere declined to below 0.01 mg L"1 at pH <8.0. In Chapter 2, it was demonstrated that CaS03 prevented a pH drop in coal refuse slurry when 0.2 gCaS03 was added to a 2% fresh coal refuse slurry every three days. Calcium sulfite also inhibited acid leaching from fresh coal refuse in bench-scale columns under controlled conditions. During the initial 13 weeks of leaching, the total amounts of titratable acidity, soluble H\\ Fe, and Al from CaS03-treated refuse (6.4 gin 50 g fresh coal refuse) were only 26%,10%, 32%, and 39% of those of the control columns, respectively. A combination of CaS03 with CaC03 or fly ash enhanced the inhibitory effect of CaS03 on acid leaching. Calcium sulfite-containing FGD which combined CaS03, CaC03, fly ash, and gypsum showed a much stronger inhibitory effect on acid leaching than CaS03 alone. This

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

    USGS Publications Warehouse

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

    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.

  16. New insights into the transformation of calcium sulfate hemihydrate to gypsum using time-resolved cryogenic transmission electron microscopy.

    PubMed

    Saha, Amitesh; Lee, Jinkee; Pancera, Sabrina M; Bräeu, Michael F; Kempter, Andreas; Tripathi, Anubhav; Bose, Arijit

    2012-07-31

    We use time-resolved cryogenic transmission electron microscopy (TR-cryo-TEM) on a supersaturated solution of calcium sulfate hemihydrate to examine the early stages of particle formation during the hydration of the hemihydrate. As hydration proceeds, we observe nanoscale amorphous clusters that evolve to amorphous particles and then reorganize to crystalline gypsum within tens of seconds. Our results indicate that a multistep particle formation model, where an amorphous phase forms first, followed by the transformation into a crystalline product, is applicable even at time scales of the order of tens of seconds for this system. The addition of a small amount of citric acid significantly delays the reorganization to gypsum crystals. We hypothesize that available calcium ions form complexes with the acid by binding to the carboxylic groups. Their incorporation into a growing particle produces disorder and extends the time over which the amorphous phase exists. We see evidence of patches of "trapped" amorphous phase within the growing gypsum crystals at time scales of the order of 24 h. This is confirmed by complementary X-ray diffraction experiments. Direct imaging of nanoscale samples by TR-cryo-TEM is a powerful technique for a fundamental understanding of crystallization and many other evolving systems.

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

    NASA Technical Reports Server (NTRS)

    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].

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

    NASA Technical Reports Server (NTRS)

    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.[

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

    PubMed Central

    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

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

    PubMed

    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

  1. Sulfuric acid deposition from stratospheric geoengineering with sulfate aerosols

    NASA Astrophysics Data System (ADS)

    Kravitz, Ben; Robock, Alan; Oman, Luke; Stenchikov, Georgiy; Marquardt, Allison B.

    2009-07-01

    We used a general circulation model of Earth's climate to conduct geoengineering experiments involving stratospheric injection of sulfur dioxide and analyzed the resulting deposition of sulfate. When sulfur dioxide is injected into the tropical or Arctic stratosphere, the main additional surface deposition of sulfate occurs in midlatitude bands, because of strong cross-tropopause flux in the jet stream regions. We used critical load studies to determine the effects of this increase in sulfate deposition on terrestrial ecosystems by assuming the upper limit of hydration of all sulfate aerosols into sulfuric acid. For annual injection of 5 Tg of SO2 into the tropical stratosphere or 3 Tg of SO2 into the Arctic stratosphere, neither the maximum point value of sulfate deposition of approximately 1.5 mEq m-2 a-1 nor the largest additional deposition that would result from geoengineering of approximately 0.05 mEq m-2 a-1 is enough to negatively impact most ecosystems.

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

    PubMed Central

    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 calcium hydroxyapatite. This inhibition was not mediated by decreased Ca2+ activity. Taurocholic acid (2-12 mM) did not affect hydroxyapatite formation, but antagonized glycochenodeoxycholic acid. Both amorphous and crystalline precipitates contained a surface fraction relatively rich in phosphate. The surface phosphate content was diminish by increasing glycochenodeoxycholic acid concentrations, and this relationship was interpreted as competition between bile acid and HPO4(-4) for binding sites on the calcium phosphate surface. A phosphate-rich crystal surface was associated with rapid transition from amorphous to crystalline states. These results indicate that glycochenodeoxycholic acid prevents transformation of amorphous calcium phosphate to crystalline hydroxyapatite by competitively inhibiting the accumulation of phosphate on the crystal embryo surface. PMID:1655828

  3. 40 CFR 417.120 - Applicability; description of the sulfamic acid sulfation subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... sulfamic acid sulfation subcategory. 417.120 Section 417.120 Protection of Environment ENVIRONMENTAL... CATEGORY Sulfamic Acid Sulfation Subcategory § 417.120 Applicability; description of the sulfamic acid sulfation subcategory. The provisions of this subpart are applicable to discharges resulting from...

  4. 40 CFR 417.120 - Applicability; description of the sulfamic acid sulfation subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... sulfamic acid sulfation subcategory. 417.120 Section 417.120 Protection of Environment ENVIRONMENTAL... CATEGORY Sulfamic Acid Sulfation Subcategory § 417.120 Applicability; description of the sulfamic acid sulfation subcategory. The provisions of this subpart are applicable to discharges resulting from...

  5. 40 CFR 417.130 - Applicability; description of the chlorosulfonic acid sulfation subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... chlorosulfonic acid sulfation subcategory. 417.130 Section 417.130 Protection of Environment ENVIRONMENTAL... CATEGORY Chlorosulfonic Acid Sulfation Subcategory § 417.130 Applicability; description of the chlorosulfonic acid sulfation subcategory. The provisions of this subpart are applicable to discharges...

  6. 40 CFR 417.130 - Applicability; description of the chlorosulfonic acid sulfation subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... chlorosulfonic acid sulfation subcategory. 417.130 Section 417.130 Protection of Environment ENVIRONMENTAL... CATEGORY Chlorosulfonic Acid Sulfation Subcategory § 417.130 Applicability; description of the chlorosulfonic acid sulfation subcategory. The provisions of this subpart are applicable to discharges...

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

    NASA Technical Reports Server (NTRS)

    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.

  8. Simulation of Natural Acid Sulfate Weathering in an Alpine Watershed

    NASA Astrophysics Data System (ADS)

    Bassett, R. L.; Miller, William R.; McHugh, John; Catts, John G.

    1992-09-01

    Streams with acidic sulfate compositions (pH less than 3.5) are naturally generated in the alpine Geneva Creek Basin of the southern Rocky Mountains, an area underlain by Proterozoic metamorphic and igneous rocks that are intruded by Tertiary felsic stocks with associated pyritic alteration. These naturally acidic waters are similar in composition to more familiar man-made acid mine waters or to surface waters acidified by sulfate precipitation. Detailed study of the stream compositions has revealed the principal reactions driving the weathering process and was used to estimate the relative effects of snowpack ionic input versus the solute contribution from acid attack in soil zones and groundwater. In the Geneva Creek Basin, atmospheric sources of solute represent a minor component to the stream water composition, except for chloride, which can be used to determine the fraction of contribution. The weathering process is a balance between oxidation of sulfides, dissolution of silicates, formation of the clay minerals vermiculite, kaolinite, and smectite, carbonate neutralization, and precipitation of ferric and aluminum oxyhydroxides and aluminum sulfate. The chemical analyses of snow samples, multiple samples of water from Geneva Creek and its tributaries, and the composition of primary and secondary minerals identified in the basin serve as input to a mass balance geochemical model, which facilitates the interpretation of the principal geochemical processes.

  9. Electrochemical control of brightener in acid copper sulfate plating solutions

    SciTech Connect

    Bronson, M.J. . Kansas City Div.); Hawley, M.D. )

    1990-11-01

    Electrochemical methods have been evaluated that attempt the indirect measurement of the effective concentration of a brighter additive in acid copper sulfate plating baths. The procedures all employed electrodeposition of copper on a platinum working electrode under carefully controlled conditions of mass transport, time, temperature, and potential, followed by the measurement of the charge that was required to strip the copper deposit from the working electrode. The amount of charge that was required to strip the copper deposit at a given concentration of additive varied significantly from fresh to production baths and from lot to lot of the additive. The feasibility of using electrochemical methods to control brightener additive in acid copper sulfate plating baths is discussed. 3 figs., 11 refs.

  10. Lung-clearance mechanisms following inhalation of acid sulfates

    SciTech Connect

    Wolff, R.K.; Muggenburg, B.A.; Silbaugh, S.A.; Carpenter, R.L.; Rowatt, J.D.; Hill, J.O.

    1982-08-01

    These studies have indicated that acute exposures (1-6 hrs) to sulfuric acid at levels of 0.5 to 1.0 mg/m/sup 3/ can produce impairments in mucous clearance. The impairments can last for up to a week following a 1 hr exposure. These effects and studies by others suggest that high sulfate levels in polluted conditions may be one factor in observed increases of hospital visits for respiratory problems. Long term exposures to elevated levels of sulfates resulting in decreases of clearance could also be an initiating factor in producing chronic obstructive pulmonary disease (COPD). These studies have also shown that it is the larger size fraction (0.6 to 1.0 ..mu..m) of sulfuric acid mist in the urban aerosol which is predominantly responsible for at least the acute effects.

  11. Chitosan coating to enhance the therapeutic efficacy of calcium sulfate-based antibiotic therapy in the treatment of chronic osteomyelitis

    PubMed Central

    Beenken, Karen E; Smith, James K; Skinner, Robert A; Mclaren, Sandra G; Bellamy, William; Gruenwald, M Johannes; Spencer, Horace J; Jennings, Jessica A; Haggard, Warren O; Smeltzer, Mark S

    2014-01-01

    We demonstrate that coating calcium sulfate with deacetylated chitosan enhances the elution profile of daptomycin by prolonging the period during which high concentrations of antibiotic are released. Coatings reduced initial bolus release of daptomycin by a factor of 10 to approximately 1000 μg/ml, and levels remained above 100 μg/ml for up to 10 days. Chitosan-coated and uncoated calcium sulfate implants with and without 15% daptomycin were evaluated in an experimental model of staphylococcal osteomyelitis through bacteriology scores, radiology, histopathology, and Gram staining. Significant reduction in bacteriology scores was observed for implants containing daptomycin and coated with chitosan compared with all the other groups. We confirm that the use of chitosan-coated calcium sulfate beads for local antibiotic delivery can be correlated with an improved therapeutic outcome following surgical debridement in the treatment of chronic osteomyelitis. PMID:24854984

  12. Freezing temperatures of aqueous iron(III) sulfate solutions and crystallization of a new acidic water-rich sulfate

    NASA Astrophysics Data System (ADS)

    Hennings, E.; Zürner, P.; Schmidt, H.; Voigt, W.

    2013-09-01

    An important question concerning the possibility of life under martian conditions is the existence of liquid water at low temperatures. On the martian surface, the existence of iron(III) sulfate is expected. The influence of iron(III) sulfate salt on ice deposits in respect to the formation of liquid salt brines was not investigated in the past. In this contribution, the investigation of the phase diagram of the system iron(III) sulfate-water and the influence of sulfuric acid to this system are presented. A new crystalline acidic iron(III) sulfate hydrate has been found in the ternary system iron(III) sulfate-water-sulfuric acid, which represents the most water-rich iron salt phase ever detected.

  13. Recovery of discarded sulfated lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Karami, Hassan; Asadi, Raziyeh

    The aim of this research is to recover discarded sulfated lead-acid batteries. In this work, the effect of two methods (inverse charge and chemical charge) on the reactivation of sulfated active materials was investigated. At the inverse charge, the battery is deeply discharged and the electrolyte of battery is replaced with a new sulfuric acid solution of 1.28 g cm -3. Then, the battery is inversely charged with constant current method (2 A for the battery with the nominal capacity of 40 Ah) for 24 h. At the final stage, the inversely charged battery is directly charged for 48 h. Through these processes, a discarded battery can recover its capacity to more than 80% of a similar fresh and non-sulfated battery. At the chemical charge method, there are some effective parameters that including ammonium persulfate [(NH 4) 2S 2O 8] concentration, recovery temperature and recovery time. The effect of all parameters was optimized by one at a time method. The sulfated battery is deeply discharged and then, its electrolyte was replaced by a 40% ammonium persulfate solution (as oxidant) at temperature of 50 °C. By adding of oxidant solution, the chemical charging of positive and negative plates was performed for optimum time of 1 h. The chemically charged batteries were charged with constant voltage method (2.66 V for the battery with nominal voltage and nominal capacity of 2 V and 10 Ah, respectively) for 24 h. By performing of these processes, a discarded battery can recovers its capacity to more than 84% of the similar fresh and non-sulfated battery. Discharge and cyclelife behaviors of the recovered batteries were investigated and compared with similar healthy battery. The morphology and structure of plates was studied by scanning electron microscopy (SEM) before and after recovery.

  14. Sulfation mediates activity of zosteric acid against biofilm formation.

    PubMed

    Kurth, Caroline; Cavas, Levent; Pohnert, Georg

    2015-01-01

    Zosteric acid (ZA), a metabolite from the marine sea grass Zostera marina, has attracted much attention due to its attributed antifouling (AF) activity. However, recent results on dynamic transformations of aromatic sulfates in marine phototrophic organisms suggest potential enzymatic desulfation of metabolites like ZA. The activity of ZA was thus re-investigated using biofilm assays and simultaneous analytical monitoring by liquid chromatography/mass spectrometry (LC/MS). Comparison of ZA and its non-sulfated form para-coumaric acid (CA) revealed that the active substance was in all cases the non-sulfated CA while ZA was virtually inactive. CA exhibited a strong biofilm inhibiting activity against Escherichia coli and Vibrio natriegens. The LC/MS data revealed that the apparent biofilm inhibiting effects of ZA on V. natriegens can be entirely attributed to CA released from ZA by sulfatase activity. In the light of various potential applications, the (a)biotic transformation of ZA to CA has thus to be considered in future AF formulations.

  15. Oxalic acid decreases calcium absorption in rats

    SciTech Connect

    Weaver, C.M.; Martin, B.R.; Ebner, J.S.; Krueger, C.A.

    1987-11-01

    Calcium absorption from salts and foods intrinsically labeled with /sup 45/Ca was determined in the rat model. Calcium bioavailability was nearly 10 times greater for low oxalate kale, CaCO/sub 3/ and CaCl/sub 2/ than from CaC/sub 2/O/sub 4/ (calcium oxalate) and spinach (high in oxalates). Extrinsic and intrinsic labeling techniques gave a similar assessment of calcium bioavailability from kale but not from spinach.

  16. CITRIC ACID AS A SET RETARDER FOR CALCIUM ALUMINATE PHOSPHATE CEMENTS.

    SciTech Connect

    SUGAMA,T.; BROTHERS, L.E.

    2005-01-01

    Citric acid added as set retarder significantly contributed to enhancing the setting temperature and to extending the thickening time of a calcium aluminate phosphate (CaP) geothermal cement slurry consisting of calcium aluminate cement (CAC) as the base reactant and sodium polyphosphate (NaP) solution as the acid reactant. The set-retarding activity of citric acid was due to the uptake of Ca{sup 2+} ions from the CAC by carboxylic acid groups within the citric acid. This uptake led to the precipitation of a Ca-complexed carboxylate compound as a set-retarding barrier layer on the CAC grains' surfaces. However, this barrier layer was vulnerable to disintegration by the attack of free Ca{sup 2+} ions from CAC, and also to degradation at elevated temperature, thereby promoting the generation of exothermic energy from acid-base reactions between the CAC and NaP after the barrier was broken. The exothermic reaction energy that was promoted in this way minimized the loss in strength of the citric acid-retarded cement. The phase composition assembled in both retarded and non-retarded cements after autoclaving at 180 C encompassed three reaction products, hydroxyapatite (HOAp), hydrogrossular and boehmite, which are responsible for strengthening the autoclaved cement. The first two reaction products were susceptible to reactions with sulfuric acid and sodium sulfate to form crystalline bassanite scale as the corrosion product. The boehmite phase possessed a great resistance to acid and sulfate. Although the bassanite scales clinging to the cement's surfaces were the major factor governing the loss in weight, they served in protecting the cement from further acid- and sulfate-corrosion until their spallation eventually occurred. Nevertheless, the repetitive processes of HOAp and hydrogrossular {yields} bassanite {yields} spallation played an important role in extending the useful lifetime of CaP cement in a low pH environment at 180 C.

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

    PubMed

    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 < 0.05). A larger amount of apatite was formed on PCL/CPC/CS than on PCL/CPC, while no apatite was found on PCL after simulated body fluid immersion. In addition, PCL/CPC/CS composites also had a faster in vitro degradation rate (13.05 ± 3.42% in weight loss) relative to PCL (1.79 ± 0.23%) and PCL/CPC (4.32 ± 2.18%) (p < 0.001). In animal studies, PCL/CPC/CS screws showed a greater volume loss than that of PCL or PCL/CPC at 24 weeks post-implantation. Under micro-computerized tomography observation, animals with PCL/CPC/CS implants had better osseointegration in terms of the structural parameters of the distal metaphysis, including trabecular number, trabecular spacing, and connectivity density, than the PCL screw. This study reveals that the addition of CS accelerates the biodegradation and 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

  18. Release of calcium from endolysosomes increases calcium influx through N-type calcium channels: Evidence for acidic store-operated calcium entry in neurons.

    PubMed

    Hui, Liang; Geiger, Nicholas H; Bloor-Young, Duncan; Churchill, Grant C; Geiger, Jonathan D; Chen, Xuesong

    2015-12-01

    Neurons possess an elaborate system of endolysosomes. Recently, endolysosomes were found to have readily releasable stores of intracellular calcium; however, relatively little is known about how such 'acidic calcium stores' affect calcium signaling in neurons. Here we demonstrated in primary cultured neurons that calcium released from acidic calcium stores triggered calcium influx across the plasma membrane, a phenomenon we have termed "acidic store-operated calcium entry (aSOCE)". aSOCE was functionally distinct from store-operated calcium release and calcium entry involving endoplasmic reticulum. aSOCE appeared to be governed by N-type calcium channels (NTCCs) because aSOCE was attenuated significantly by selectively blocking NTCCs or by siRNA knockdown of NTCCs. Furthermore, we demonstrated that NTCCs co-immunoprecipitated with the lysosome associated membrane protein 1 (LAMP1), and that aSOCE is accompanied by increased cell-surface expression levels of NTCC and LAMP1 proteins. Moreover, we demonstrated that siRNA knockdown of LAMP1 or Rab27a, both of which are key proteins involved in lysosome exocytosis, attenuated significantly aSOCE. Taken together our data suggest that aSOCE occurs in neurons, that aSOCE plays an important role in regulating the levels and actions of intraneuronal calcium, and that aSOCE is regulated at least in part by exocytotic insertion of N-type calcium channels into plasma membranes through LAMP1-dependent lysosome exocytosis.

  19. Sulfate but Not Thiosulfate Reduces Calculated and Measured Urinary Ionized Calcium and Supersaturation: Implications for the Treatment of Calcium Renal Stones

    PubMed Central

    Rodgers, Allen; Gauvin, Daniel; Edeh, Samuel; Allie-Hamdulay, Shameez; Jackson, Graham; Lieske, John C.

    2014-01-01

    Background Urinary sulfate (SO42−) and thiosulfate (S2O32−) 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. Methods 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. Results 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. Conclusion 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. PMID:25061988

  20. Hydration state of calcium sulfates in Gale crater, Mars: Identification of bassanite veins

    NASA Astrophysics Data System (ADS)

    Rapin, W.; Meslin, P.-Y.; Maurice, S.; Vaniman, D.; Nachon, M.; Mangold, N.; Schröder, S.; Gasnault, O.; Forni, O.; Wiens, R. C.; Martínez, G. M.; Cousin, A.; Sautter, V.; Lasue, J.; Rampe, E. B.; Archer, D.

    2016-10-01

    In-situ analyses reveal the presence of hydrogen within calcium sulfate veins crosscutting the sediments found in Gale crater. Laboratory experiments were performed to calibrate the hydrogen signal measured by laser induced breakdown spectroscopy (LIBS) in a range applicable to martian data. The analyses indicate that all veins targeted so far at Gale consist predominantly of bassanite which most likely formed by dehydration of gypsum. This scenario suggests that the percolating water produced gypsum, possibly by hydration of anhydrite in aqueous solution, and remained at temperatures below ∼60 °C at that time. Desiccating conditions followed, consistent with a hyperarid climate and favored by burial or impacts. Additionally, anhydrite with lesser bassanite has been found by XRD in samples of sediments hosting the veins. Our result suggests bassanite is likely found in the veins and anhydrite may be more common as a fine-grained component within the sediments.

  1. Crystallization of calcium sulfate dihydrate in the presence of some metal ions

    NASA Astrophysics Data System (ADS)

    Hamdona, Samia K.; Al Hadad, Umaima A.

    2007-02-01

    Crystallization of calcium sulfate dihydrate (CaSO 4·2H 2O gypsum) in sodium chloride solutions in the presence of some metal ions, and over a range of relative super-saturation has been studied. The addition of metal ions, even at relatively low concentration (10 -6 mol l -1), markedly retard the rate of crystallization of gypsum. Retardation effect was enhanced with increase in the additives contents. Moreover, the effect was enhanced as the relative super-saturation decreases. Influence of mixed additives on the rate of crystallization (Cd 2++Arg, Cd 2++H 3PO 4 and Cd 2++PAA) has also been studied. Direct adsorption experiments of these metal ions on the surface of gypsum crystals have been made for comparison.

  2. Dual roles of borax in kinetics of calcium sulfate dihydrate formation.

    PubMed

    Jiang, Wenge; Pan, Haihua; Tao, Jinhui; Xu, Xurong; Tang, Ruikang

    2007-04-24

    An additive is not exclusively retardant or promoter for a crystallization system. The kinetic studies of calcium sulfate dihydrate (CSD) crystal growth demonstrated that borax played dual roles in the reaction, which accelerated CSD formations at the low concentration levels but inhibited the crystal growth at the high ones. In situ atomic force microscopy studies revealed that borax modulated the CSD crystallization via two different pathways: promoted the secondary nucleation to increase the step density on the growing crystal faces but simultaneously retarded the spread of these growth steps by the Langmuir adsorption. These two contradictory factors were incorporated in the crystallization, and their balance was regulated by the borax concentration. Both the macroscopic and microscopic experimental data nicely displayed the crystallization model of birth and spread that was able to account for the behaviors of borax in CSD formations.

  3. Development of an injectable bioactive bone filler cement with hydrogen orthophosphate incorporated calcium sulfate.

    PubMed

    Sony, Sandhya; Suresh Babu, S; Nishad, K V; Varma, Harikrishna; Komath, Manoj

    2015-01-01

    Calcium sulfate cement (CSC) has emerged as a potential bone filler material mainly because of the possibility of incorporating therapeutic agents. Delivery of the cement through a needle or cannula will make it more useful in clinical applications. However, it was not possible to make CSC injectable because of the inherent lack of viscosity. The present work demonstrates the design development of a viscous and fully-injectable CSC by incorporating hydrogen orthophosphate ions, which does not hamper the biocompatibility of the material. The effect of addition of hydrogen orthophosphate on the rheological properties of the CSC paste was studied using a custom made capillary rheometer. The physicochemical changes associated with cement setting process were examined using X-ray diffraction and Fourier transform infrared spectroscopy and the thermal changes were measured through isothermal differential scanning calorimetry. Micromorphological features of different compositions were observed in environmental scanning electron microscopy and the presence of phosphate ions was identified with energy dispersive X-ray spectroscopic analysis and inductively coupled plasma-optical emission spectroscopy. The results indicated that HPO4 (2-) ions have profound effects on the rheological properties and setting of the CSC paste. Significant finding is that the HPO4 (2-) ions are getting substituted in the calcium sulfate dihydrate crystals during setting. The variations of setting time and compressive strength of the cement with the additive concentration were investigated. An optimum concentration of 2.5 % w/w gave a fully-injectable cement with clinically relevant setting time (below 20 min) and compressive strength (12 MPa). It was possible to inject the optimised cement paste from a syringe through an 18-gauge needle with thumb pressure. This cement will be useful both as bone filler and as a local drug delivery medium and it allows minimally invasive bone defect management.

  4. Augmentation of screw fixation with injectable calcium sulfate bone cement in ovariectomized rats.

    PubMed

    Yu, Xiao-Wei; Xie, Xin-Hui; Yu, Zhi-Feng; Tang, Ting-Ting

    2009-04-01

    The objective of this study was to determine the effect of augmenting screw fixation with an injectable calcium sulfate cement (CSC) in the osteoporotic bone of ovariectomized rats. The influence of the calcium sulfate (CS) on bone remodeling and screw anchorage in osteoporotic cancellous bone was systematically investigated using histomorphometric and biomechanical analyses. The femoral condyles of 55 Sprague-Dawley ovariectomized rats were implanted with screw augmented with CS, while the contralateral limb received a nonaugmented screw. At time intervals of 2, 4, 8, 12, and 16 weeks, 11 rats were euthanized. Six pair-matched samples were used for histological analysis, while five pair-matched samples were preserved for biomechanical testing. Histomorphometric data showed that CS augmented screws activated cancellous bone formation, evidenced by a statistically higher (p < 0.05) percentage of osteoid surface at 2, 4, and 8 weeks and a higher rate of bone mineral apposition at 12 weeks compared with nonaugmented screws. The amount of the bone-screw contact at 2, 8, and 12 weeks and of bone ingrowth on the threads at 4 and 8 weeks was greater in the CS group than in the nonaugmented group (p < 0.05), although these parameters increased concomitantly with time for both groups. The CS was resorbed completely at 8 weeks without stimulating fibrous encapsulation on the screw surface. Also, the cement significantly increased the screw pull-out force and the energy to failure at 2, 4, 8, and 12 weeks after implantation, when compared with the control group (p < 0.05). These results imply that augmentation of screw fixation with CS may have the potential to decrease the risk of implant failure in osteoporotic bone.

  5. Development of an injectable bioactive bone filler cement with hydrogen orthophosphate incorporated calcium sulfate.

    PubMed

    Sony, Sandhya; Suresh Babu, S; Nishad, K V; Varma, Harikrishna; Komath, Manoj

    2015-01-01

    Calcium sulfate cement (CSC) has emerged as a potential bone filler material mainly because of the possibility of incorporating therapeutic agents. Delivery of the cement through a needle or cannula will make it more useful in clinical applications. However, it was not possible to make CSC injectable because of the inherent lack of viscosity. The present work demonstrates the design development of a viscous and fully-injectable CSC by incorporating hydrogen orthophosphate ions, which does not hamper the biocompatibility of the material. The effect of addition of hydrogen orthophosphate on the rheological properties of the CSC paste was studied using a custom made capillary rheometer. The physicochemical changes associated with cement setting process were examined using X-ray diffraction and Fourier transform infrared spectroscopy and the thermal changes were measured through isothermal differential scanning calorimetry. Micromorphological features of different compositions were observed in environmental scanning electron microscopy and the presence of phosphate ions was identified with energy dispersive X-ray spectroscopic analysis and inductively coupled plasma-optical emission spectroscopy. The results indicated that HPO4 (2-) ions have profound effects on the rheological properties and setting of the CSC paste. Significant finding is that the HPO4 (2-) ions are getting substituted in the calcium sulfate dihydrate crystals during setting. The variations of setting time and compressive strength of the cement with the additive concentration were investigated. An optimum concentration of 2.5 % w/w gave a fully-injectable cement with clinically relevant setting time (below 20 min) and compressive strength (12 MPa). It was possible to inject the optimised cement paste from a syringe through an 18-gauge needle with thumb pressure. This cement will be useful both as bone filler and as a local drug delivery medium and it allows minimally invasive bone defect management

  6. Acid copper sulfate plating bath: Control of chloride and copper

    SciTech Connect

    Borhani, K.J.

    1992-08-01

    Plated-through holes in high-reliability printed wiring boards require a ductile copper plate of uniform consistency. The level of control of the chemical constituents in the electroplating solutions dictates the physical properties of the copper plate. To improve the control of the chemical bath constituents, in-situ methods for electrochemically determining copper and chloride in acid copper sulfate baths were developed. A solid-state ion-selective electrode was used for the chloride ion and proved to be more reproducible than conventional silver chloride turbidimetric methods. The use of a copper solid-state ion-selective electrode in-situ was also successful in this application.

  7. [Alteration of the acute toxicity and various pharmacologic effects of streptomycin sulfate by calcium 4'-phosphopantothenate].

    PubMed

    Dorofeev, B F; Korablev, M V; Kopelevich, V M

    1983-10-01

    The effect of calcium 4'-phosphopantothenate (CPP) on acute toxicity of streptomycin and the decrease by the antibiotic of the muscle working capacity, "holes" reflex, body temperature and oxygen intake was studied on 258 albino mice weighing 22-26 g. Medical calcium pantothenate (CPA) was used for control purposes. CPP is an antagonist of streptomycin sulfate. In a dose of 1/10 or 1/5 of the LD50 injected intraperitoneally CPP lowered acute toxicity of streptomycin and prevented its effect in a dose of 0.11--1.1 g/kg injected subcutaneously on the muscle working capacity, "holes" reflex and body temperature. The spectrum index of the CPP antitoxic effect was equal to 22.5. By its acute toxicity CPP (LD50 1.18 +/- 0.07 g/kg) did not differ from CPA (LD50 1.25 +/- 0.08 g/kg). The efficacy of CPP, by its antitoxic spectrum, was 1.8 times higher than that of CPA. CPA lowered the streptomycin effect on the "holes" reflex and body temperature, while CPP prevented it. Both the drugs did not influence the decrease in the oxygen consumption induced by streptomycin. PMID:6651265

  8. Quantitative analysis of glycosaminoglycans, chondroitin/dermatan sulfate, hyaluronic acid, heparan sulfate, and keratan sulfate by liquid chromatography-electrospray ionization-tandem mass spectrometry.

    PubMed

    Osago, Harumi; Shibata, Tomoko; Hara, Nobumasa; Kuwata, Suguru; Kono, Michihaya; Uchio, Yuji; Tsuchiya, Mikako

    2014-12-15

    We developed a method using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) with a selected reaction monitoring (SRM) mode for simultaneous quantitative analysis of glycosaminoglycans (GAGs). Using one-shot analysis with our MS/MS method, we demonstrated the simultaneous quantification of a total of 23 variously sulfated disaccharides of four GAG classes (8 chondroitin/dermatan sulfates, 1 hyaluronic acid, 12 heparan sulfates, and 2 keratan sulfates) with a sensitivity of less than 0.5 pmol within 20 min. We showed the differences in the composition of GAG classes and the sulfation patterns between porcine articular cartilage and yellow ligament. In addition to the internal disaccharides described above, some saccharides derived from the nonreducing terminal were detected simultaneously. The simultaneous quantification of both internal and nonreducing terminal saccharides could be useful to estimate the chain length of GAGs. This method would help to establish comprehensive "GAGomic" analysis of biological tissues.

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

    PubMed

    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

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

    PubMed

    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

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

    PubMed Central

    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

  12. Diet acids and alkalis influence calcium retention in bone.

    PubMed

    Buclin, T; Cosma, M; Appenzeller, M; Jacquet, A F; Décosterd, L A; Biollaz, J; Burckhardt, P

    2001-01-01

    The urine-acidifying properties of food constituents depend on their content of non-oxidizable acids or precursors. Acidifying constituents such as animal proteins may negatively affect calcium metabolism and accelerate bone resorption, thus representing an aggravating factor for osteoporosis. This four-period, double-crossover study investigated whether a diet intervention specifically focused on acid load could modify calcium metabolism in humans. Eight healthy volunteers underwent a four-day metabolic preparation with two types of diets, one rich in acid ash-forming nutrients, and one providing base-forming nutrients (including bicarbonate-rich mineral water), both having similar contents of calcium, phosphate, sodium, proteins and calories. On the fourth day, a single oral dose of 1 g calcium was given, either as carbonate or as gluconolactate. Serial blood and urine samples revealed that the diet affected blood pH (average difference 0.014, p=0.002) and urine pH (average difference 1.02, p<0.0001) in the expected direction, but had no influence on the absorption of the calcium supplement. The acid-forming diet increased urinary calcium excretion by 74% when compared with the base-forming diet (p<0.0001), both at baseline and after the oral calcium load, and C-telopeptide excretion by 19% (p=0.01), suggesting a skeletal origin for the excess calcium output. This observation confirms that renally excreted acids derived from food influence calcium metabolism, and that alkalizing nutrients inhibit bone resorption. Further studies are needed to determine the clinical impact of dietary counseling for avoiding diet acids as a preventive measure against osteoporosis. PMID:11446566

  13. Preparation of manganese sulfate from low-grade manganese carbonate ores by sulfuric acid leaching

    NASA Astrophysics Data System (ADS)

    Lin, Qing-quan; Gu, Guo-hua; Wang, Hui; Zhu, Ren-feng; Liu, You-cai; Fu, Jian-gang

    2016-05-01

    In this study, a method for preparing pure manganese sulfate from low-grade ores with a granule mean size of 0.47 mm by direct acid leaching was developed. The effects of the types of leaching agents, sulfuric acid concentration, reaction temperature, and agitation rate on the leaching efficiency of manganese were investigated. We observed that sulfuric acid used as a leaching agent provides a similar leaching efficiency of manganese and superior selectivity against calcium compared to hydrochloric acid. The optimal leaching conditions in sulfuric acid media were determined; under the optimal conditions, the leaching efficiencies of Mn and Ca were 92.42% and 9.61%, respectively. Moreover, the kinetics of manganese leaching indicated that the leaching follows the diffusion-controlled model with an apparent activation energy of 12.28 kJ·mol-1. The purification conditions of the leaching solution were also discussed. The results show that manganese dioxide is a suitable oxidant of ferrous ions and sodium dimethyldithiocarbamate is an effective precipitant of heavy metals. Finally, through chemical analysis and X-ray diffraction analysis, the obtained product was determined to contain 98% of MnSO4·H2O.

  14. Synergistic effects of dimethyloxalylglycine and butyrate incorporated into α-calcium sulfate on bone regeneration.

    PubMed

    Woo, Kyung Mi; Jung, Hong-Moon; Oh, Joung-Hwan; Rahman, Saeed Ur; Kim, Soung Min; Baek, Jeong-Hwa; Ryoo, Hyun-Mo

    2015-01-01

    Osteogenesis is closely related to angiogenesis, and the combined delivery of angiogenic and osteogenic factors has been suggested to enhance bone regeneration. Small molecules have been explored as alternatives to growth factors for tissue regeneration applications. In this study, we examined the effects of the combined application of angiogenic and osteogenic small molecules on bone regeneration using a prolyl hydroxylase, dimethyloxalylglycine (DMOG), and a histone deacetylase inhibitor, butyrate. In a critical size bone defect model in rats, DMOG and butyrate, which were incorporated into α calcium sulfate (αCS), resulted in synergistic enhancements in bone and blood vessel formation, eventually leading to bone healing, as confirmed by micro-CT and histological analyses. In MC4 pre-osteoblast cultures, DMOG and butyrate enhanced the pro-angiogenic responses and osteoblast differentiation, respectively, which were evaluated based on the levels of hypoxia inducible factor (HIF)-1α protein and the expression of pro-angiogenic molecules (VEGF, home oxidase-1, glucose transporter-1) and by alkaline phosphatase (ALP) activity and the expression of osteoblast phenotype marker molecules (ALP, α1(I)col, osteocalcin, and bone sialoprotein). DMOG combined with butyrate synergistically improved osteoblast differentiation and pro-angiogenic responses, the levels of which were drastically increased in the cultures on αCS disks. Furthermore, it was demonstrated that αCS increased the level of HIF-1α and as a consequence VEGF expression, and supported osteoblast differentiation through the release of calcium ions from the αCS. Altogether, the results of this study provide evidence that a combination treatment with the small molecules DMOG and butyrate can expedite the process of bone regeneration and that αCS can be an efficient delivery vehicle for the small molecules for bone regeneration.

  15. The stable isotope geochemistry of acid sulfate alteration

    USGS Publications Warehouse

    Rye, R.O.; Bethke, P.M.; Wasserman, M.D.

    1992-01-01

    Acid sulfate wall-rock alteration, characterized by the assemblage alunite + kaolinite + quartz ?? pyrite, results from base leaching by fluids concentrated in H2SO4. Requisite amounts of H2SO4 can be generated by different mechanisms in three principal geologic environments: 1) by atmospheric oxidation of sulfides in the supergene environment, 2) by atmospheric oxidation at the water table in the steam-heated environment of H2S released by deeper, boiling fluids, and 3) by the disproportionation of magmatic SO2 to H2S and H2SO4 during condensation of a magmatic vapor plume at intermediate depths in magmatic hydrothermal environments in silicic and andesitic volcanic terranes. In addition, coarse vein alunite may form in a magmatic steam environment. -from Authors

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

    PubMed Central

    2015-01-01

    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. PMID:26114102

  17. Crystallization of calcium oxalate monohydrate at dipalmitoylphosphatidylcholine monolayers in the presence of chondroitin sulfate A

    NASA Astrophysics Data System (ADS)

    Ouyang, Jian-Ming; Deng, Sui-Ping; Zhong, Jiu-Ping; Tieke, Bernd; Yu, Shu-Hong

    2004-10-01

    The growth and aggregation of calcium oxalate monohydrate (COM) crystals beneath dipalmitoylphosphatidylcholine (DPPC) monolayers in the presence of chondroitin sulfate A (C4S) was systematically examined under different surface pressure. The results indicated that the addition of C4S can inhibit the crystal growth and prevent the aggregation of COM crystals. Under a DPPC monolayer, well-defined three-dimensional hexagonal prisms and three-dimensional rhombus prisms with sharply angled tips were obtained. The DPPC monolayer at a surface pressure of 10 mN/m can match the Ca2+ distance of the (1 bar 0 1) face of COM better than at 20 mN/m. The addition of C4S could cooperatively modulate the interaction strength between the monolayer (or itself) with the specific morphology determining faces such as (1 bar 0 1) and (0 2 0), and thus results in remarkable stabilization of the (1 bar 0 1) faces. The dramatic changes in morphological details were due to the strong electrostatic interactions between the Ca2+-rich (1 bar 0 1) crystal faces of COM and the polyanionic polysaccharide C4S together with the negatively charged sites of the zwitterionic DPPC monolayers. The increase of the concentration of C4S can further enhance the stabilization of the (1 bar 0 1) face.

  18. Formation of calcium sulfate through the aggregation of sub-3 nanometre primary species.

    PubMed

    Stawski, Tomasz M; van Driessche, Alexander E S; Ossorio, Mercedes; Diego Rodriguez-Blanco, Juan; Besselink, Rogier; Benning, Liane G

    2016-01-01

    The formation pathways of gypsum remain uncertain. Here, using truly in situ and fast time-resolved small-angle X-ray scattering, we quantify the four-stage solution-based nucleation and growth of gypsum (CaSO4·2H2O), an important mineral phase on Earth and Mars. The reaction starts through the fast formation of well-defined, primary species of <3 nm in length (stage I), followed in stage II by their arrangement into domains. The variations in volume fractions and electron densities suggest that these fast forming primary species contain Ca-SO4-cores that self-assemble in stage III into large aggregates. Within the aggregates these well-defined primary species start to grow (stage IV), and fully crystalize into gypsum through a structural rearrangement. Our results allow for a quantitative understanding of how natural calcium sulfate deposits may form on Earth and how a terrestrially unstable phase-like bassanite can persist at low-water activities currently dominating the surface of Mars. PMID:27034256

  19. Engineering scaffolds integrated with calcium sulfate and oyster shell for enhanced bone tissue regeneration.

    PubMed

    Shen, Yue; Yang, Shizhou; Liu, Jianli; Xu, Huazi; Shi, Zhongli; Lin, Zhongqing; Ying, Xiaozhou; Guo, Peng; Lin, Tiao; Yan, Shigui; Huang, Qing; Peng, Lei

    2014-08-13

    Engineering scaffolds combinging natural biomineral and artificially synthesized material hold promising potential for bone tissue regeneration. In this study, novel bioactive calcium sulfate/oyster shell (CS/OS) composites were prepared. Comparing to CS scaffold, the CS/OS composites with a controllable degradation rate displayed enhanced mineral nodule formation, higher alkaline phosphate (ALP) activity and increased proliferation rate while treated osteocytes. In CS/OS composites group, elevated mRNA levels of key osteogenic genes including bone morphogenetic protein-2 (BMP-2), runt-related transcription factor 2 (Runx2), osterix (Osx), and osteocalcin (OCN) were observed. Furthermore, The up-regulation of BMP-2 and type I collagen (COL-I) was observed for CS/OS composites relative to a CS group. Scaffolds were implanted into critical-sized femur cavity defects in rabbits to investigate the osteogenic capacity of the composites in vivo. The CS/OS scaffolds with proper suitable times and mechanical strength strongly promoted osteogenic tissue regeneration relative to the regeneration capacity of CS scaffolds, as indicated by the results of histological staining. These results suggest that the OS-modified CS engineering scaffolds with improved mechanical properties and bioactivity would facilitate the development of a new strategy for clinic bone defect regeneration. PMID:25033438

  20. Engineering scaffolds integrated with calcium sulfate and oyster shell for enhanced bone tissue regeneration.

    PubMed

    Shen, Yue; Yang, Shizhou; Liu, Jianli; Xu, Huazi; Shi, Zhongli; Lin, Zhongqing; Ying, Xiaozhou; Guo, Peng; Lin, Tiao; Yan, Shigui; Huang, Qing; Peng, Lei

    2014-08-13

    Engineering scaffolds combinging natural biomineral and artificially synthesized material hold promising potential for bone tissue regeneration. In this study, novel bioactive calcium sulfate/oyster shell (CS/OS) composites were prepared. Comparing to CS scaffold, the CS/OS composites with a controllable degradation rate displayed enhanced mineral nodule formation, higher alkaline phosphate (ALP) activity and increased proliferation rate while treated osteocytes. In CS/OS composites group, elevated mRNA levels of key osteogenic genes including bone morphogenetic protein-2 (BMP-2), runt-related transcription factor 2 (Runx2), osterix (Osx), and osteocalcin (OCN) were observed. Furthermore, The up-regulation of BMP-2 and type I collagen (COL-I) was observed for CS/OS composites relative to a CS group. Scaffolds were implanted into critical-sized femur cavity defects in rabbits to investigate the osteogenic capacity of the composites in vivo. The CS/OS scaffolds with proper suitable times and mechanical strength strongly promoted osteogenic tissue regeneration relative to the regeneration capacity of CS scaffolds, as indicated by the results of histological staining. These results suggest that the OS-modified CS engineering scaffolds with improved mechanical properties and bioactivity would facilitate the development of a new strategy for clinic bone defect regeneration.

  1. Properties and Osteogenicity of Two Calcium Sulfate Materials with Micro or Nano Morphology.

    PubMed

    Zhang, Chunli; Li, Zhonghai; Li, Qihong; Han, Liwei; Zhu, Jialiang; Bai, Yulong; Ge, Cheng; Zhao, Yantao; Zhong, Hongbin

    2016-03-01

    Calcium sulfate dihydrate (CaSO4 x 2H2O, CSD) was widely used as the artificial bone graft. In this study, two kinds of CSD materials were characterized with XRD, TG/DTA, FT-IR, and SEM. They were both composed of CSD. Spherical shape particles were observed for nano-CSD with diameters of 52-300 nm. The micro-CSD were thin sheet particles with dimensions of 5-10 μm. At 56 days post-implantation in vivo, nano-CSD had good tissue compatibility. A frequently used bioactive material DBM, which was the combination of nano-CSD (nano-CSD-DBM) and micro-CSD (micro-CSD-DBM) in a 1:1 weight ratio separately. Composite materials were implanted in intramuscular pockets in nude mouse model. New bone mineralization could be both observed in the surgery site. Collagen I was also widely distributed by immunohistochemistry assay. And new bone area of nano-CSD-DBM was 28 ± 4.6% at 4 weeks post-operation. But new bone area of micro-CSD-DBM was 16 ± 3.7% (less than nano-CSD-DBM). Nano-CSD showed increased degradation rate with obvious anginogenicity. And nano-CSD-DBM showed more excellent bone induction property as bone substitute implant.

  2. Formation of calcium sulfate through the aggregation of sub-3 nanometre primary species

    PubMed Central

    Stawski, Tomasz M.; van Driessche, Alexander E.S.; Ossorio, Mercedes; Diego Rodriguez-Blanco, Juan; Besselink, Rogier; Benning, Liane G.

    2016-01-01

    The formation pathways of gypsum remain uncertain. Here, using truly in situ and fast time-resolved small-angle X-ray scattering, we quantify the four-stage solution-based nucleation and growth of gypsum (CaSO4·2H2O), an important mineral phase on Earth and Mars. The reaction starts through the fast formation of well-defined, primary species of <3 nm in length (stage I), followed in stage II by their arrangement into domains. The variations in volume fractions and electron densities suggest that these fast forming primary species contain Ca–SO4-cores that self-assemble in stage III into large aggregates. Within the aggregates these well-defined primary species start to grow (stage IV), and fully crystalize into gypsum through a structural rearrangement. Our results allow for a quantitative understanding of how natural calcium sulfate deposits may form on Earth and how a terrestrially unstable phase-like bassanite can persist at low-water activities currently dominating the surface of Mars. PMID:27034256

  3. Formation of calcium sulfate through the aggregation of sub-3 nanometre primary species

    NASA Astrophysics Data System (ADS)

    Stawski, Tomasz M.; van Driessche, Alexander E. S.; Ossorio, Mercedes; Diego Rodriguez-Blanco, Juan; Besselink, Rogier; Benning, Liane G.

    2016-04-01

    The formation pathways of gypsum remain uncertain. Here, using truly in situ and fast time-resolved small-angle X-ray scattering, we quantify the four-stage solution-based nucleation and growth of gypsum (CaSO4.2H2O), an important mineral phase on Earth and Mars. The reaction starts through the fast formation of well-defined, primary species of <3 nm in length (stage I), followed in stage II by their arrangement into domains. The variations in volume fractions and electron densities suggest that these fast forming primary species contain Ca-SO4-cores that self-assemble in stage III into large aggregates. Within the aggregates these well-defined primary species start to grow (stage IV), and fully crystalize into gypsum through a structural rearrangement. Our results allow for a quantitative understanding of how natural calcium sulfate deposits may form on Earth and how a terrestrially unstable phase-like bassanite can persist at low-water activities currently dominating the surface of Mars.

  4. Solubility of the Sodium and Ammonium Salts of Oxalic Acid in Water with Ammonium Sulfate.

    PubMed

    Buttke, Lukas G; Schueller, Justin R; Pearson, Christian S; Beyer, Keith D

    2016-08-18

    The solubility of the sodium and ammonium salts of oxalic acid in water with ammonium sulfate present has been studied using differential scanning calorimetry, X-ray crystallography, and infrared spectroscopy. The crystals that form from aqueous mixtures of ammonium sulfate/sodium hydrogen oxalate were determined to be sodium hydrogen oxalate monohydrate under low ammonium sulfate conditions and ammonium hydrogen oxalate hemihydrate under high ammonium sulfate conditions. Crystals from aqueous mixtures of ammonium sulfate/sodium oxalate were determined to be ammonium oxalate monohydrate under moderate to high ammonium sulfate concentrations and sodium oxalate under low ammonium sulfate concentrations. It was also found that ammonium sulfate enhances the solubility of the sodium oxalate salts (salting in effect) and decreases the solubility of the ammonium oxalate salts (salting out effect). In addition, a partial phase diagram for the ammonium hydrogen oxalate/water system was determined.

  5. Solubility of the Sodium and Ammonium Salts of Oxalic Acid in Water with Ammonium Sulfate.

    PubMed

    Buttke, Lukas G; Schueller, Justin R; Pearson, Christian S; Beyer, Keith D

    2016-08-18

    The solubility of the sodium and ammonium salts of oxalic acid in water with ammonium sulfate present has been studied using differential scanning calorimetry, X-ray crystallography, and infrared spectroscopy. The crystals that form from aqueous mixtures of ammonium sulfate/sodium hydrogen oxalate were determined to be sodium hydrogen oxalate monohydrate under low ammonium sulfate conditions and ammonium hydrogen oxalate hemihydrate under high ammonium sulfate conditions. Crystals from aqueous mixtures of ammonium sulfate/sodium oxalate were determined to be ammonium oxalate monohydrate under moderate to high ammonium sulfate concentrations and sodium oxalate under low ammonium sulfate concentrations. It was also found that ammonium sulfate enhances the solubility of the sodium oxalate salts (salting in effect) and decreases the solubility of the ammonium oxalate salts (salting out effect). In addition, a partial phase diagram for the ammonium hydrogen oxalate/water system was determined. PMID:27482644

  6. Acid sulfate soils are an environmental hazard in Finland

    NASA Astrophysics Data System (ADS)

    Pihlaja, Jouni

    2016-04-01

    Acid sulfate soils (ASS) create significant threats to the environment on coastal regions of the Baltic Sea in Finland. The sediments were deposited during the ancient Litorina Sea phase of the Baltic Sea about 7500-4500 years ago. Finland has larger spatial extent of the ASS than any other European country. Mostly based on anthropogenic reasons (cultivation, trenching etc.) ASS deposits are currently being exposed to oxygen which leads to chemical reaction creating sulfuric acid. The acidic waters then dissolve metals form the soil. Acidic surface run off including the metals are then leached into the water bodies weakening the water quality and killing fish or vegetation. In constructed areas acidic waters may corrode building materials. Geological Survey of Finland (GTK) is mapping ASS deposits in Finland. The goal is to map a total of 5 million hectares of the potentially ASS affected region. It has been estimated that the problematic Litorina Sea deposits, which are situated 0-100 m above the recent Baltic Sea shoreline, cover 500 000 hectares area. There are several phases in mapping. The work begins at the office with gathering the existing data, interpreting airborne geophysical data and compiling a field working plan. In the field, quality of the soil is studied and in uncertain cases samples are taken to laboratory analyses. Also electrical conductivity and pH of soil and water are measured in the field. Laboratory methods include multielemental determinations with ICP-OES, analyses of grain size and humus content (LOI), and incubation. So far, approximately 60 % of the potential ASS affected regions in Finland are mapped. Over 15 000 sites have been studied in the field and 4000 laboratory analyses are done. The spatial database presented in the scale of 1: 250 000 can be viewed at the GTK's web pages (http://gtkdata.gtk.fi/hasu/index.html).

  7. Use of sulfate reducing bacteria in acid mine drainage treatment

    SciTech Connect

    Powers, T.J.

    1995-10-01

    The environmental impacts caused by Acid Mine Drainage (AMD) were first recorded in 1556 by Georgius Agricola. In the United States 10,000 miles of streams and 29,000 surface acres of impoundments are estimated to be seriously affected by AMD. Abandoned surface mines are estimated to contribute about 15% of the drainage, while active mines (40%) and shaft and drift mines (45%) contribute the remainder. AMD results when metal sulfide minerals, particularly pyrite (FeS{sub 2}), come in contact with oxygen and water. Acid generation occurs when metal sulfide minerals are oxidized according to the Initiator Reaction: FeS{sub 2}(pyrite) + 3 1/2O{sub 2} + H{sub 2}O {yields} Fe{sup 2+} + 2SO{sub 4}{sup 2-} + 2H{sup +}. This reaction is one of many that results in increased metal mobility and increased acidity (lowered pH) of the mine water. The oxidation of ferrous sulfate is accelerated by bacterial action of Thiobacillus ferrooxidans, a naturally occurring bacterium that at pH 3.5 or less, can rapidly accelerate the conversion of dissolved Fe{sup 2+} (ferrous iron) to Fe{sup 3+} (ferric iron), and can act as an oxidant for the oxidation of pyrite. Ferric ions, as well as other metal ions, and the sulfuric acid have a deleterious influence on the biota of streams receiving AMD. The Lilly/Orphan Boy Mine, located in the Elliston Mining District of Powell County, Montana, was selected as the Sulfate Reducing Bacteria (SRB) technology demonstration site. The mine is situated on a patented claim on Deerlodge National Forest Land about 11 miles south of Elliston, Montana. This abandoned mining operation consists of a 250-foot shaft, four horizontal workings, and some stopping. The shaft is flooded with AMD to the 74-foot level and is discharging about 3 gallons per minute (gpm) at a pH of 3.0 from the adit associated with this level.

  8. Interaction of calcium sulfate with xanthan gum: effect on in vitro bioadhesion and drug release behavior from xanthan gum based buccal discs of buspirone.

    PubMed

    Jaipal, A; Pandey, M M; Abhishek, A; Vinay, S; Charde, S Y

    2013-11-01

    Bioadhesive polymers in buccal drug delivery systems play an important role in delivery of therapeutic drug molecules for local and systemic action. Xanthan gum, a GRAS listed natural polymer was used to design buccal discs of buspirone hydrochloride by direct compression method. Effect of calcium sulfate on bioadhesive and drug release behavior of xanthan gum buccal discs was studied. Varying amount of calcium sulfate (0%, 5%, 10%, 20%, 30%, 40% and 50%, w/w) in combination with xanthan gum was used to prepare buccal bioadhesive discs. Increase in calcium sulfate concentration resulted in faster drug release and decreased the bioadhesive strength of the designed discs. Further, in rheological evaluation it was observed that viscosity of xanthan gum gel reduces with increasing concentration of calcium sulfate. Compatibility of drug with various excipients was assessed using DSC and FTIR techniques. PMID:23907052

  9. Determination of optimal sulfate concentration for methane production from volatile fatty acids

    SciTech Connect

    Demafelis, R.B.; Tomita, Osamu; Kajiuchi, Toshio

    1996-12-31

    The effect of sulfate on methane production from individual volatile fatty acids were investigated using batch cultures. Optimum sulfate concentrations were found to be at 220mg/l for propionate digestion and 55mg/l for butyrate and valerate digestions. Methane productions were significantly increased at these conditions compared to cultures containing no sulfates. Hydrogen sulfide levels, at optimum sulfate concentration were relatively low up to 0.7 % in the gas phase. Sulfate reducing bacteria (SRB) predominates the bacterial population while Methanosaeta concilii outnumbered Methanospirillium hungatei. 7 refs., 3 figs.

  10. Uptake of Ambient Organic Gases to Acidic Sulfate Aerosols

    NASA Astrophysics Data System (ADS)

    Liggio, J.; Li, S.

    2009-05-01

    The formation of secondary organic aerosols (SOA) in the atmosphere has been an area of significant interest due to its climatic relevance, its effects on air quality and human health. Due largely to the underestimation of SOA by regional and global models, there has been an increasing number of studies focusing on alternate pathways leading to SOA. In this regard, recent work has shown that heterogeneous and liquid phase reactions, often leading to oligomeric material, may be a route to SOA via products of biogenic and anthropogenic origin. Although oligomer formation in chamber studies has been frequently observed, the applicability of these experiments to ambient conditions, and thus the overall importance of oligomerization reactions remain unclear. In the present study, ambient air is drawn into a Teflon smog chamber and exposed to acidic sulfate aerosols which have been formed in situ via the reaction of SO3 with water vapor. The aerosol composition is measured with a High Resolution Aerodyne Aerosol Mass Spectrometer (HR-ToF-AMS), and particle size distributions are monitored with a scanning mobility particle sizer (SMPS). The use of ambient air and relatively low inorganic particle loading potentially provides clearer insight into the importance of heterogeneous reactions. Results of experiments, with a range of sulfate loadings show that there are several competing processes occurring on different timescales. A significant uptake of ambient organic gases to the particles is observed immediately followed by a slow shift towards higher m/z over a period of several hours indicating that higher molecular weight products (possibly oligomers) are being formed through a reactive process. The results suggest that heterogeneous reactions can occur with ambient organic gases, even in the presence of ammonia, which may have significant implications to the ambient atmosphere where particles may be neutralized after their formation.

  11. A simplified method for estimation of jarosite and acid-forming sulfates in acid mine wastes.

    PubMed

    Li, Jun; Smart, Roger St C; Schumann, Russell C; Gerson, Andrea R; Levay, George

    2007-02-01

    In acid base accounting (ABA) estimates of acid mine wastes, the acid potential (AP) estimate can be improved by using the net carbonate value (NCV) reactive sulfide S method rather than total S assay methods but this does not give recovery of potentially acid producing ferrous and ferric sulfates present in many wastes. For more accurate estimation of AP, an effective, site-specific method to quantify acid sulfate salts, such as jarosite and melanterite, in waste rocks has been developed and tested on synthetic and real wastes. The SPOCAS (acid sulfate soils) methods have been modified to an effective, rapid method to speciate sulfate forms in different synthetic waste samples. A three-step sequential extraction procedure has been established. These steps are: (1) argon-purged water extraction (3 min) to extract soluble Fe(II) salts (particularly melanterite), epsomite and gypsum (<10 wt.%), (2) roasting at 550 degrees C (1 h) to remove sulfur from pyrite and other reactive sulfides, (3) HCl extraction (4 M, 30 min) for determination of jarosites. Products (solid and aqueous) have been characterized at each step including the jarosite decomposition process in Step 2 where temperature control is critical to avoid S loss. The sequential extraction procedure was used to quantitatively determine melanterite, epsomite, gypsum, pyrite and jarosite concentrations in a synthetic waste sample containing these mineral phases at 5 wt.% in quartz, and also tested using a tailings waste sample to quantitatively determine epsomite, gypsum and jarosite contents. The method is applicable to most waste samples including those with non-pyrite sulfides but for samples containing significant amounts of sulfur (>1 wt.% S) as copper sulfides, the second step of roasting needs to be excluded from the procedure with an increased time of 4 M HCl extraction to 16 h for jarosite determination.

  12. Stabilization of Submicron Calcium Oxalate Suspension by Chondroitin Sulfate C May Be an Efficient Protection from Stone Formation

    PubMed Central

    Li, Jun-Jun; Xue, Jun-Fa; Ouyang, Jian-Ming

    2013-01-01

    The influences of chondroitin sulfate C (C6S) on size, aggregation, sedimentation, and Zeta potential of sub-micron calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) crystallites with mean sizes of about 330 nm were investigated using an X-ray diffractometer, nanoparticle size Zeta potential analyzer, ultraviolet spectrophotometer, and scanning electron microscope, after which the results were compared with those of micron-grade crystals. C6S inhibited the conversion of COD to COM and the aggregation of COM and COD crystallitesis; it also decreased their sedimentation rate, thus increasing their stability in aqueous solution. The smaller the size of the COD crystallites, the easier they can be converted to COM. The stability of sub-micron COD was worse than that of micron-grade crystals. C6S can inhibit the formation of calcium oxalate stones. PMID:24382950

  13. Calcium Sulfate Vein Observations at Yellowknife Bay using ChemCam on the Curiosity Rover

    NASA Astrophysics Data System (ADS)

    Clegg, S. M.; Mangold, N.; Nachon, M.; Le Mouelic, S.; Ollila, A.; Vaniman, D. T.; Kah, L. C.; Dromart, G.; Bridges, J.; Rice, M. S.; Wellington, D. F.; Bell, J. F.; Anderson, R. B.; Clark, B. C.; Cousin, A.; Forni, O.; Lasue, J.; Schröder, S.; Meslin, P.; Dyar, M. D.; Blaney, D. L.; Maurice, S.; Wiens, R. C.; Team, M.

    2013-12-01

    The Mars Science Laboratory Curiosity rover completed its traverse from the Bradbury landing site into Yellowknife Bay (YKB) on sol 125, where it spent ~175 sols. The YKB region is characterized as a fluvio-lacustrine depositional environment. The entire Curiosity payload was used to thoroughly investigate parts of YKB from which significant geochemical observations were made, including the identification of anhydrite and hydrated calcium sulfate. The Curiosity ChemCam package consists of a remote Laser-Induced Breakdown Spectrometer (LIBS) and a Remote Micro-Imager (RMI). LIBS is essentially an elemental analysis micro-probe capable of 300 - 550 μm spatial resolution from 1.5 - 7.0 m standoff distance from the Curiosity mast. The RMI records context images that have a resolution of 40 μrad, which corresponds to 120 μm at 3 meters. The ChemCam instrument recorded many calcium rich geochemical features as it descended ~18 m into YKB. Many light-toned veins became apparent with the ChemCam RMI and Mastcam once Curiosity entered YKB. The ChemCam LIBS instrument is uniquely capable of distinctly probing the elemental composition of these vein structures separately from the host rock. LIBS demonstrated that the white vein material was dominated by CaSO4, while the host rock had relatively low SO3 compositions. The ChemCam instrument can also qualitatively detect H, presumably due to H2O, in many samples. While some of these veins contained no H signature beyond the ubiquitous small amount of H on rock surfaces and in soils, some of the veins contained various amounts of H as a function of depth indicating that some of the samples were either bassanite or gypsum. Mastcam spectral hydration surveys detect evidence of hydration that is consistent with (but not a unique indicator of) the presence of gypsum in some, but not all, of the veins. The CheMin X-ray diffraction instrument identified both anhydrite and bassanite in the matrix of a mudstone unit but did not detect

  14. Biocompatibility of artificial bone based on vancomycin loaded mesoporous silica nanoparticles and calcium sulfate composites.

    PubMed

    Gu, Jisheng; Wang, Teng; Fan, Guoxin; Ma, Junhua; Hu, Wei; Cai, Xiaobing

    2016-04-01

    The aim of this study was to evaluate the in vitro and in vivo biocompatibility of artificial bone based on vancomycin loaded mesoporous silica nanoparticles and calcium sulfate composites. In vitro cytotoxicity tests by cholecystokinin octapeptide (CCK-8) assay showed that the 5%Van-MSN-CaSO4 and Van-CaSO4 bone cements were cytocompatible for mouse osteoblastic cell line MC3T3-E1. The microscopic observation confirmed that MC3T3-E1cells incubated with Van-CaSO4 group and 5%Van-MSN-CaSO4 group exhibited clear spindle-shaped changes, volume increase and maturation, showing that these cements supported adhesion of osteoblastic cells on their surfaces. In addition, the measurement of alkaline phosphatase activity revealed the osteoconductive property of these biomaterials. In order to assess in vivo biocompatibility, synthesized cements were implanted into the distal femur of twelve adult male and female New Zealand rabbits. After implantation in artificial defects of the distal femur, 5%Van-MSN-CaSO4 and Van-CaSO4 bone cements did not damage the function of main organs of rabbits. In addition, the Van-MSN-CaSO4 composite allowed complete repair of bone defects with new bone formation 3 months after implantation. These results show potential application of Van-MSN-CaSO4 composites as bone graft materials for the treatment of open fracture in human due to its mechanical, osteoconductive and potential sustained drug release characteristics and the absence of adverse effects on the body.

  15. Inactivation of Prions by Acidic Sodium Dodecyl Sulfate

    PubMed Central

    Peretz, David; Supattapone, Surachai; Giles, Kurt; Vergara, Julie; Freyman, Yevgeniy; Lessard, Pierre; Safar, Jiri G.; Glidden, David V.; McCulloch, Charles; Nguyen, Hoang-Oanh B.; Scott, Michael; DeArmond, Stephen J.; Prusiner, Stanley B.

    2006-01-01

    Prompted by the discovery that prions become protease-sensitive after exposure to branched polyamine dendrimers in acetic acid (AcOH) (S. Supattapone, H. Wille, L. Uyechi, J. Safar, P. Tremblay, F. C. Szoka, F. E. Cohen, S. B. Prusiner, and M. R. Scott, J. Virol. 75:3453-3461, 2001), we investigated the inactivation of prions by sodium dodecyl sulfate (SDS) in weak acid. As judged by sensitivity to proteolytic digestion, the disease-causing prion protein (PrPSc) was denatured at room temperature by SDS at pH values of ≤4.5 or ≥10. Exposure of Sc237 prions in Syrian hamster brain homogenates to 1% SDS and 0.5% AcOH at room temperature resulted in a reduction of prion titer by a factor of ca. 107; however, all of the bioassay hamsters eventually developed prion disease. When various concentrations of SDS and AcOH were tested, the duration and temperature of exposure acted synergistically to inactivate both hamster Sc237 prions and human sporadic Creutzfeldt-Jakob disease (sCJD) prions. The inactivation of prions in brain homogenates and those bound to stainless steel wires was evaluated by using bioassays in transgenic mice. sCJD prions were more than 100,000 times more resistant to inactivation than Sc237 prions, demonstrating that inactivation procedures validated on rodent prions cannot be extrapolated to inactivation of human prions. Some procedures that significantly reduced prion titers in brain homogenates had a limited effect on prions bound to the surface of stainless steel wires. Using acidic SDS combined with autoclaving for 15 min, human sCJD prions bound to stainless steel wires were eliminated. Our findings form the basis for a noncorrosive system that is suitable for inactivating prions on surgical instruments, as well as on other medical and dental equipment. PMID:16352557

  16. In vivo contribution of amino acid sulfur to cartilage proteoglycan sulfation

    PubMed Central

    Pecora, Fabio; Gualeni, Benedetta; Forlino, Antonella; Superti-Furga, Andrea; Tenni, Ruggero; Cetta, Giuseppe; Rossi, Antonio

    2006-01-01

    Cytoplasmic sulfate for sulfation reactions may be derived either from extracellular fluids or from catabolism of sulfur-containing amino acids and other thiols. In vitro studies have pointed out the potential relevance of sulfur-containing amino acids as sources for sulfation when extracellular sulfate concentration is low or when its transport is impaired such as in DTDST [DTD (diastrophic dysplasia) sulfate transporter] chondrodysplasias. In the present study, we have considered the contribution of cysteine and cysteine derivatives to in vivo macromolecular sulfation of cartilage by using the mouse model of DTD we have recently generated [Forlino, Piazza, Tiveron, Della Torre, Tatangelo, Bonafe, Gualeni, Romano, Pecora, Superti-Furga et al. (2005) Hum. Mol. Genet. 14, 859–871]. By intraperitoneal injection of [35S]cysteine in wild-type and mutant mice and determination of the specific activity of the chondroitin 4-sulfated disaccharide in cartilage, we demonstrated that the pathway by which sulfate is recruited from the intracellular oxidation of thiols is active in vivo. To check whether cysteine derivatives play a role, sulfation of cartilage proteoglycans was measured after treatment for 1 week of newborn mutant and wild-type mice with hypodermic NAC (N-acetyl-L-cysteine). The relative amount of sulfated disaccharides increased in mutant mice treated with NAC compared with the placebo group, indicating an increase in proteoglycan sulfation due to NAC catabolism, although pharmacokinetic studies demonstrated that the drug was rapidly removed from the bloodstream. In conclusion, cysteine contribution to cartilage proteoglycan sulfation in vivo is minimal under physiological conditions even if extracellular sulfate availability is low; however, the contribution of thiols to sulfation becomes significant by increasing their plasma concentration. PMID:16719839

  17. Microbial community potentially responsible for acid and metal release from an Ostrobothnian acid sulfate soil

    PubMed Central

    Wu, Xiaofen; Lim Wong, Zhen; Sten, Pekka; Engblom, Sten; Österholm, Peter; Dopson, Mark; Nakatsu, Cindy

    2013-01-01

    Soils containing an approximately equal mixture of metastable iron sulfides and pyrite occur in the boreal Ostrobothnian coastal region of Finland, termed ‘potential acid sulfate soil materials’. If the iron sulfides are exposed to air, oxidation reactions result in acid and metal release to the environment that can cause severe damage. Despite that acidophilic microorganisms catalyze acid and metal release from sulfide minerals, the microbiology of acid sulfate soil (ASS) materials has been neglected. The molecular phylogeny of a depth profile through the plough and oxidized ASS layers identified several known acidophilic microorganisms and environmental clones previously identified from acid- and metal-contaminated environments. In addition, several of the 16S rRNA gene sequences were more similar to sequences previously identified from cold environments. Leaching of the metastable iron sulfides and pyrite with an ASS microbial enrichment culture incubated at low pH accelerated metal release, suggesting microorganisms capable of catalyzing metal sulfide oxidation were present. The 16S rRNA gene analysis showed the presence of species similar to Acidocella sp. and other clones identified from acid mine environments. These data support that acid and metal release from ASSs was catalyzed by indigenous microorganisms adapted to low pH. PMID:23369102

  18. Antibrowning and antimicrobial properties of sodium acid sulfate in apple slices.

    PubMed

    Fan, Xuetong; Sokorai, Kimberly J B; Liao, Ching-Hsing; Cooke, Peter; Zhang, Howard Q

    2009-01-01

    There are few available compounds that can both control browning and enhance microbial safety of fresh-cut fruits. In the present study, the antibrowning ability of sodium acid sulfate (SAS) on "Granny Smith" apple slices was first investigated in terms of optimum concentration and treatment time. In a separate experiment, the apple slices were treated with water or 3% of SAS, calcium ascorbate, citric acid, or acidified calcium sulfate for 5 min. Total plate count, color, firmness, and tissue damage were assessed during a 21-d storage at 4 degrees C. Results showed that the efficacy of SAS in inhibiting browning of apple slices increased with increasing concentration. A minimum 3% of SAS was needed to achieve 14 d of shelf life. Firmness was not significantly affected by SAS at 3% or lower concentrations. Antibrowning potential of SAS was similar for all treatment times ranging from 2 to 10 min. However, SAS caused some skin discoloration of apple slices. When cut surface of apple slices were stained with a fluorescein diacetate solution, tissue damage could be observed under a microscope even though visual damage was not evident. Among the antibrowning agents tested, SAS was the most effective in inhibiting browning and microbial growth for the first 14 d. Total plate count of samples treated with 3% SAS was significantly lower than those treated with calcium ascorbate, a commonly used antibrowning agent. Our results suggested that it is possible to use SAS to control browning while inhibiting the growth of microorganisms on the apple slices if the skin damage can be minimized. Practical Application: Fresh-cut apples have emerged as one of the popular products in restaurants, schools, and food service establishments as more consumers demand fresh, convenient, and nutritious foods. Processing of fresh-cut apples induces mechanical damage to the fruit and exposes apple tissue to air, resulting in the development of undesirable tissue browning. The fresh

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

    SciTech Connect

    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].

  20. Isotopically exchangeable Al in coastal lowland acid sulfate soils.

    PubMed

    Yvanes-Giuliani, Yliane A M; Fink, D; Rose, J; Waite, T David; Collins, Richard N

    2016-01-15

    Periodic discharges of high concentrations of aluminium (Al) causing fish kills and other adverse effects occur worldwide in waterways affected by coastal lowland acid sulfate soils (CLASS). The exchangeability - a metal's ability to readily transfer between the soil solid- and solution-phases - of Al in these soils is therefore of particular importance as it has implications for metal transport, plant availability and toxicity to living organisms. In the present study, the concentrations of isotopically exchangeable Al (E values) were measured in 27 CLASS and compared with common salt extractions (i.e. KCl and CuCl2) used to estimate exchangeable soil pools of Al. E values of Al were high in the soils, ranging from 357 to 3040 mg·kg(-1). Exchangeable concentrations estimated using 1 M KCl were consistently lower than measured E values, although a reasonable correlation was obtained between the two values (E=1.68×AlKCl, r(2)=0.66, n=25). The addition of a 0.2 M CuCl2 extraction step improved the 1:1 agreement between extractable and isotopically exchangeable Al concentrations, but lead to significant mobilisation of non-isotopically exchangeable Al in surficial 'organic-rich' CLASS having E values<1000 mg·kg(-1). It was concluded that currently used (i.e. 1 M KCl) methodology severely underestimates exchangeable Al and total actual acidity values in CLASS and should be corrected by a factor similar to the one determined here. PMID:26519574

  1. Evaluation of lead anode reactions in acid sulfate electrolytes. 1: Lead alloys with cobalt additives

    SciTech Connect

    Yu, P.; O`Keefe, T.J.

    1999-04-01

    Lead alloys, such as lead-calcium-tin and lead-silver, are the primary insoluble anodes used in the electrowinning of metals. While some difficulties are encountered in their use, there is no obvious replacement that is economically and technically competitive. Two of the specific problems with lead include decreased cathode purity due to incorporation from corrosion products and the relatively high overpotential which increases cell voltage. To gain an improved understanding of the fundamental behavior of lead anodes, the polarization behavior of six different alloys in sulfuric acid was evaluated. Some tests were also made with Co(II) in the acid sulfate electrolyte. Notable differences were found in the multiple activation-passivation cycles, stability, and relative activity for oxygen evolution for the alloys, and the relative trends in behavior were established. Electrochemical impedance spectroscopy studies were also conducted at selected potentials. Overall, the data show that the electrochemical response, particularly the degree of polarization for the oxygen evolution reaction, of the lead alloy anodes are dependent on the surface phases and structures present. The ability to depolarize the anode reaction using Co(II) was particularly sensitive to the lead composition.

  2. [The effectiveness of sulfate magnesium-calcium mineral water for the treatment of the patients presenting with chronic acalculous cholecystitis].

    PubMed

    Tudakova, V G; Vladimirskiĭ, E V; Kunstman, T G

    2013-01-01

    This paper was designed to report the results of investigations into the therapeutic effectiveness of "Kluchi" sulfate magnesiumcalcium mineral water used to treat 194 patients presenting with chronic acalculous cholecystitis and different types of biliary tract dysfunction. The control group was comprised of 92 patients who took a diet. It was shown, that mineral water "Kluchi" exerted well apparent beneficial action on the motor function of the gallbladder and the sphincter apparatus. Moreover, drinking the mineral water improved colloidal stability of bile. It is concluded that the therapeutic application of "Kluchi" sulfate magnesium-calcium mineral water results in the reduction of bile lihogenicity, produces anti-inflammatory and choleretic effects, and promotes normalization of the motor and tonic condition of the biliary tract. PMID:23819416

  3. Hydroxylation, conjugation and sulfation of bile acids in primary monolayer cultures of rat hepatocytes

    SciTech Connect

    Princen, H.M.; Meijer, P.

    1988-08-15

    Hydroxylation of lithocholic, chenodeoxycholic, deoxycholic and cholic acids was studied in monolayers of rat hepatocytes cultured for 76 h. The majority of added lithocholic and chenodeoxycholic acids was metabolized to beta-muricholic acid (56-76%). A small part of these bile acids (9%), however, and a considerable amount of deoxycholic and cholic acids (21%) were converted into metabolites more polar than cholic acid in the first culture period. Formation of these compounds decreased during the last day of culture. Bile acids synthesized after addition of (4-/sup 14/C)-cholesterol were almost entirely (97%) sulfated and/or conjugated, predominantly with taurine (54-66%), during culture. Sulfated bile acids were mainly composed of free bile acids. The ability of hepatocytes to sulfurylate bile acids declined with culture age. Thus, rat hepatocytes in primary monolayer culture are capable to sulfurylate bile acids and to hydroxylate trihydroxylated bile acids, suggesting formation of polyhydroxylated metabolites.

  4. STATISTICAL VALIDATION OF SULFATE QUANTIFICATION METHODS USED FOR ANALYSIS OF ACID MINE DRAINAGE

    EPA Science Inventory

    Turbidimetric method (TM), ion chromatography (IC) and inductively coupled plasma atomic emission spectrometry (ICP-AES) with and without acid digestion have been compared and validated for the determination of sulfate in mining wastewater. Analytical methods were chosen to compa...

  5. An in vivo swine study for xeno-grafts of calcium sulfate-based bone grafts with human dental pulp stem cells (hDPSCs).

    PubMed

    Kuo, Tzong-fu; Lee, Sheng-Yang; Wu, Hong-Da; Poma, Malosi; Wu, Yu-Wei; Yang, Jen-Chang

    2015-05-01

    The purpose of this in vivo study was to evaluate the effect of human dental pulp stem cells (hDPSCs) on various resorbable calcium sulfate/calcium phosphate bone grafts in bone regeneration. Granular particles of calcium sulfate dehydrate (CSD), α-calcium sulfate hemihydrate/amorphous calcium phosphate (α-CSH/ACP), and CSD/β-tricalcium phosphates (β-TCP) were prepared for in vitro dissolution and implantation test. The chemical compositions of specimen residues after dissolution test were characterized by XRD. The ratios of new bone formation for implanted grafts/hDPSCs were evaluated using mandible bony defect model of Lanyu pig. All the graft systems exhibited a similar two-stage dissolution behavior and phase transformation of poor crystalline HAp. Eight weeks post-operation, the addition of hDPSCs to various graft systems showed statistically significant increasing in the ratio of new bone formation (p<0.05). Null hypothesis of hDPSCs showing no scaffold dependence in bone regeneration was rejected. The results suggest that the addition of hDPSCs to calcium sulfate based xenografts could enhance the bone regeneration in the bony defect. PMID:25746240

  6. Laboratory Simulated Acid-Sulfate Weathering of Basaltic Materials: Implications for Formation of Sulfates at Meridiani Planum and Gusev Crater, Mars

    NASA Technical Reports Server (NTRS)

    Golden, D. C.; Ming, Douglas W.; Morris, Richard V.; Mertzman, A.

    2006-01-01

    Acid-sulfate weathering of basaltic materials is a candidate formation process for the sulfate-rich outcrops and rocks at the MER rover Opportunity and Spirit landing sites. To determine the style of acid-sulfate weathering on Mars, we weathered basaltic materials (olivine-rich glassy basaltic sand and plagioclase feldspar-rich basaltic tephra) in the laboratory under different oxidative, acid-sulfate conditions and characterized the alteration products. We investigated alteration by (1) sulfuric-acid vapor (acid fog), (2) three-step hydrothermal leaching treatment approximating an open system and (3) single-step hydrothermal batch treatment approximating a "closed system." In acid fog experiments, Al, Fe, and Ca sulfates and amorphous silica formed from plagioclase-rich tephra, and Mg and Ca sulfates and amorphous silica formed from the olivine-rich sands. In three-step leaching experiments, only amorphous Si formed from the plagioclase-rich basaltic tephra, and jarosite, Mg and Ca sulfates and amorphous silica formed from olivine-rich basaltic sand. Amorphous silica formed under single-step experiments for both starting materials. Based upon our experiments, jarosite formation in Meridiani outcrop is potential evidence for an open system acid-sulfate weathering regime. Waters rich in sulfuric acid percolated through basaltic sediment, dissolving basaltic phases (e.g., olivine) and forming jarosite, other sulfates, and iron oxides. Aqueous alteration of outcrops and rocks on the West Spur of the Columbia Hills may have occurred when vapors rich in SO2 from volcanic sources reacted with basaltic materials. Soluble ions from the host rock (e.g., olivine) reacted with S to form Ca-, Mg-, and other sulfates along with iron oxides and oxyhydroxides.

  7. Calcium Binding to Amino Acids and Small Glycine Peptides in Aqueous Solution: Toward Peptide Design for Better Calcium Bioavailability.

    PubMed

    Tang, Ning; Skibsted, Leif H

    2016-06-01

    Deprotonation of amino acids as occurs during transfer from stomach to intestines during food digestion was found by comparison of complex formation constants as determined electrochemically for increasing pH to increase calcium binding (i) by a factor of around 6 for the neutral amino acids, (ii) by a factor of around 4 for anions of the acidic amino acids aspartic and glutamic acid, and (iii) by a factor of around 5.5 for basic amino acids. Optimized structures of the 1:1 complexes and ΔHbinding for calcium binding as calculated by density functional theory (DFT) confirmed in all complexes a stronger calcium binding and shorter calcium-oxygen bond length in the deprotonated form. In addition, the stronger calcium binding was also accompanied by a binding site shift from carboxylate binding to chelation by α-amino group and carboxylate oxygen for leucine, aspartate, glutamate, alanine, and asparagine. For binary amino acid mixtures, the calcium-binding constant was close to the predicted geometric mean of the individual amino acid binding constants indicating separate binding of calcium to two amino acids when present together in solution. At high pH, corresponding to conditions for calcium absorption, the binding affinity increased in the order Lys < Arg < Cys < Gln < Gly ∼ Ala < Asn < His < Leu < Glu< Asp. In a series of glycine peptides, calcium-binding affinity was found to increase in the order Gly-Leu ∼ Gly-Gly < Ala-Gly < Gly-His ∼ Gly-Lys-Gly < Glu-Cys-Gly < Gly-Glu, an ordering confirmed by DFT calculations for the dipeptides and which also accounted for large synergistic effects in calcium binding for up to 6 kJ/mol when compared to the corresponding amino acid mixtures.

  8. Efflorescent sulfates from Baia Sprie mining area (Romania)--Acid mine drainage and climatological approach.

    PubMed

    Buzatu, Andrei; Dill, Harald G; Buzgar, Nicolae; Damian, Gheorghe; Maftei, Andreea Elena; Apopei, Andrei Ionuț

    2016-01-15

    The Baia Sprie epithermal system, a well-known deposit for its impressive mineralogical associations, shows the proper conditions for acid mine drainage and can be considered a general example for affected mining areas around the globe. Efflorescent samples from the abandoned open pit Minei Hill have been analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman and near-infrared (NIR) spectrometry. The identified phases represent mostly iron sulfates with different hydration degrees (szomolnokite, rozenite, melanterite, coquimbite, ferricopiapite), Zn and Al sulfates (gunningite, alunogen, halotrichite). The samples were heated at different temperatures in order to establish the phase transformations among the studied sulfates. The dehydration temperatures and intermediate phases upon decomposition were successfully identified for each of mineral phases. Gunningite was the single sulfate that showed no transformations during the heating experiment. All the other sulfates started to dehydrate within the 30-90 °C temperature range. The acid mine drainage is the main cause for sulfates formation, triggered by pyrite oxidation as the major source for the abundant iron sulfates. Based on the dehydration temperatures, the climatological interpretation indicated that melanterite formation and long-term presence is related to continental and temperate climates. Coquimbite and rozenite are attributed also to the dry arid/semi-arid areas, in addition to the above mentioned ones. The more stable sulfates, alunogen, halotrichite, szomolnokite, ferricopiapite and gunningite, can form and persists in all climate regimes, from dry continental to even tropical humid. PMID:26544892

  9. Formation of diphenylthioarsinic acid from diphenylarsinic acid under anaerobic sulfate-reducing soil conditions.

    PubMed

    Hisatomi, Shihoko; Guan, Ling; Nakajima, Mami; Fujii, Kunihiko; Nonaka, Masanori; Harada, Naoki

    2013-11-15

    Diphenylarsinic acid (DPAA) is a toxic phenylarsenical compound often found around sites contaminated with phenylarsenic chemical warfare agents, diphenylcyanoarsine or diphenylchloroarsine, which were buried in soil after the World Wars. This research concerns the elucidation of the chemical structure of an arsenic metabolite transformed from DPAA under anaerobic sulfate-reducing soil conditions. In LC/ICP-MS analysis, the retention time of the metabolite was identical to that of a major phenylarsenical compound synthesized by chemical reaction of DPAA and hydrogen sulfide. Moreover the mass spectra for the two compounds measured using LC/TOF-MS were similar. Subsequent high resolution mass spectral analysis indicated that two major ions at m/z 261 and 279, observed on both mass spectra, were attributable to C12H10AsS and C12H12AsSO, respectively. These findings strongly suggest that the latter ion is the molecular-related ion ([M+H](+)) of diphenylthioarsinic acid (DPTA; (C6H5)2AsS(OH)) and the former ion is its dehydrated fragment. Thus, our results reveal that DPAA can be transformed to DPTA, as a major metabolite, under sulfate-reducing soil conditions. Moreover, formation of diphenyldithioarsinic acid and subsequent dimerization were predicted by the chemical reaction analysis of DPAA with hydrogen sulfide. This is the first report to elucidate the occurrence of DPAA-thionation in an anaerobic soil. PMID:24007995

  10. Simultaneous sulfate and zinc removal from acid wastewater using an acidophilic and autotrophic biocathode.

    PubMed

    Teng, Wenkai; Liu, Guangli; Luo, Haiping; Zhang, Renduo; Xiang, Yinbo

    2016-03-01

    The aim of this study was to develop microbial electrolysis cell (MEC) with a novel acidophilic and autotrophic biocathode for treatment of acid wastewater. A biocathode was developed using acidophilic sulfate-reducing bacteria as the catalyst. Artificial wastewater with 200mgL(-1) sulfate and different Zn concentrations (0, 15, 25, and 40 mg L(-1)) was used as the MEC catholyte. The acidophilic biocathode dominated by Desulfovibrio sp. with an abundance of 66% (with 82% of Desulfovibrio sequences similar to Desulfovibrio simplex) and achieved a considerable sulfate reductive rate of 32 gm(-3)d(-1). With 15 mg L(-1) Zn added, the sulfate reductive rate of MEC improved by 16%. The formation of ZnS alleviated the inhibition from sulfide and sped the sulfate reduction. With 15 and 25 mgL(-1) Zn added, more than 99% of Zn was removed from the wastewater. Dissolved Zn ions in the catholyte were converted into insoluble Zn compounds, such as zinc sulfide and zinc hydroxide, due to the sulfide and elevated pH produced by sulfate reduction. The MEC with acidophilic and autotrophic biocathode can be used as an alternative to simultaneously remove sulfate and metals from acid wastewaters, such as acid mine drainage.

  11. Simultaneous sulfate and zinc removal from acid wastewater using an acidophilic and autotrophic biocathode.

    PubMed

    Teng, Wenkai; Liu, Guangli; Luo, Haiping; Zhang, Renduo; Xiang, Yinbo

    2016-03-01

    The aim of this study was to develop microbial electrolysis cell (MEC) with a novel acidophilic and autotrophic biocathode for treatment of acid wastewater. A biocathode was developed using acidophilic sulfate-reducing bacteria as the catalyst. Artificial wastewater with 200mgL(-1) sulfate and different Zn concentrations (0, 15, 25, and 40 mg L(-1)) was used as the MEC catholyte. The acidophilic biocathode dominated by Desulfovibrio sp. with an abundance of 66% (with 82% of Desulfovibrio sequences similar to Desulfovibrio simplex) and achieved a considerable sulfate reductive rate of 32 gm(-3)d(-1). With 15 mg L(-1) Zn added, the sulfate reductive rate of MEC improved by 16%. The formation of ZnS alleviated the inhibition from sulfide and sped the sulfate reduction. With 15 and 25 mgL(-1) Zn added, more than 99% of Zn was removed from the wastewater. Dissolved Zn ions in the catholyte were converted into insoluble Zn compounds, such as zinc sulfide and zinc hydroxide, due to the sulfide and elevated pH produced by sulfate reduction. The MEC with acidophilic and autotrophic biocathode can be used as an alternative to simultaneously remove sulfate and metals from acid wastewaters, such as acid mine drainage. PMID:26561748

  12. Sulfate Mineral Formation from Acid-Weathered Phyllosilicates: Implications for the Aqueous History of Mars

    NASA Technical Reports Server (NTRS)

    Craig, P. I.; Ming, D. W.; Rampe, E. B.; Morris, R. V.

    2015-01-01

    Phyllosilicates on Mars are thought to have formed under neutral to alkaline conditions during Mars' earliest Noachian geologic era (approx. 4.1-3.7 Gya). Sulfate formation, on the other hand, requires more acidic conditions which are thought to have occurred later during Mars' Hesperian era (approx. 3.7-3.0 Gya). Therefore, regions on Mars where phyllosilicates and sulfates are found in close proximity to each other provide evidence for the geologic and aqueous conditions during this global transition. Both phyllosilicates and sulfates form in the presence of water and thus give clues to the aqueous history of Mars and its potential for habitability. Phyllosilicates that formed during the Noachian era may have been weathered by the prevailing acidic conditions that characterize the Hesperian. Therefore, the purpose of this study is to characterize the alteration products resulting from acid-sulfate weathered phyllosilicates in laboratory experiments. This study focuses on two phyllosilicates commonly identified with sulfates on Mars: nontronite and saponite. We also compare our results to observations of phyllosilicates and sulfates on Mars to better understand the formation process of sulfates in close proximity to phyllosilicates on Mars and constrain the aqueous conditions of these regions on Mars.

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

    NASA Technical Reports Server (NTRS)

    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 (< 2mm/y). The hyper-arid conditions allow extraordinary accumulations of sulfates, chlorides, and nitrates in Atacama soils. Examining salt accumulations in the Atacama may assist understanding salt accumulations on Mars. Recent work examining sulfate soils on basalt parent material observed white material in the interior vesicles of surface basalt. This is strikingly similar to the bright-white material present in veins and vesicles of the Adirondack basalt rocks at Gusev Crater which are presumed to consist of S, Cl, and/or Br. The abundance of soil gypsum/anhydrite in the area of the Atacama basalt suggested that the white material consisted of 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.

  14. Sulfate in acid rain data - do the patterns make sense?

    SciTech Connect

    Stensland, G.J.

    1997-12-31

    A high quality national record of precipitation chemistry is being collected through the operation of the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). This network began in 1978 with less than 20 sites and by the mid 1980`s had grown to about 200 sites which is about the number of sites currently in operation. Lynch et al. have been reporting time trend results for this data, with their most recent analysis showing that sulfate in NADP/NTN decreased dramatically in 1995 which agrees with the substantial decrease in sulfur dioxide emissions. The various network data available before NADP/NTN have been reported to have a variety of problems, especially related to the effect on pH of the elevated levels of base cations. The sulfate and nitrate data may be more useable. This paper reassesses the sulfate data available from the Junge network to see if these data can be used to extend the comparison of sulfate in precipitation and sulfur dioxide emissions back to the mid 1950`s.

  15. Modeling Analysis for Characterizing Sulfate Reduction at an Acid Mine Drainage Site

    NASA Astrophysics Data System (ADS)

    Sengupta, A.; Ahlfeld, D. P.

    2004-05-01

    A field site has been established at Davis Mine, an abandoned pyrite mine in rural Rowe, Massachusetts in the United States. At the site, attenuation restricts the extent of AMD in both the groundwater and surface water of the area. Current research is examining the Fe(III) and sulfate reduction along with a complex community of acidophilic and acid-tolerant anaerobic microorganisms. In an effort to interlink the geochemical reduction with the microbial community existing in the site, the role of the Fe(III) and sulfate reducing bacteria is being investigated. Initial experimental data and column studies have shown the presence of sulfate reducing bacteria at the site. A detailed groundwater flow model for the affected site has been developed. A model is currently being developed of the various geochemical and biological processes at Davis Mine for use in distinguishing between sulfate reduction and dilution as they affect observed sulfate attenuation.

  16. Dermatan sulfate epimerase 1-deficient mice have reduced content and changed distribution of iduronic acids in dermatan sulfate and an altered collagen structure in skin.

    PubMed

    Maccarana, Marco; Kalamajski, Sebastian; Kongsgaard, Mads; Magnusson, S Peter; Oldberg, Ake; Malmström, Anders

    2009-10-01

    Dermatan sulfate epimerase 1 (DS-epi1) and DS-epi2 convert glucuronic acid to iduronic acid in chondroitin/dermatan sulfate biosynthesis. Here we report on the generation of DS-epi1-null mice and the resulting alterations in the chondroitin/dermatan polysaccharide chains. The numbers of long blocks of adjacent iduronic acids are greatly decreased in skin decorin and biglycan chondroitin/dermatan sulfate, along with a parallel decrease in iduronic-2-O-sulfated-galactosamine-4-O-sulfated structures. Both iduronic acid blocks and iduronic acids surrounded by glucuronic acids are also decreased in versican-derived chains. DS-epi1-deficient mice are smaller than their wild-type littermates but otherwise have no gross macroscopic alterations. The lack of DS-epi1 affects the chondroitin/dermatan sulfate in many proteoglycans, and the consequences for skin collagen structure were initially analyzed. We found that the skin collagen architecture was altered, and electron microscopy showed that the DS-epi1-null fibrils have a larger diameter than the wild-type fibrils. The altered chondroitin/dermatan sulfate chains carried by decorin in skin are likely to affect collagen fibril formation and reduce the tensile strength of DS-epi1-null skin.

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

    NASA Astrophysics Data System (ADS)

    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.

  18. Spontaneous precipitation of calcium carbonate in the presence of chondroitin sulfate

    NASA Astrophysics Data System (ADS)

    Manoli, F.; Dalas, E.

    2000-08-01

    The kinetics of spontaneous precipitation of vaterite (CaCO 3) from an aqueous solution in the presence of chondroitin sulfates (CSA, CSB, CSC) was investigated by the constant composition method. The presence of chondroitin sulfate in the supersaturated solution resulted in a reduction of the crystal growth rate by 23-65%. Induction times preceding vaterite precipitation were inversely proportional to the solution's supersaturation and a surface energy of 52 mJ m -2 was calculated according to the classical nucleation theory. Chondroitin sulfate influences the particle size distribution of the vaterite crystals formed and stabilizing this mineral phase, preventing the transformation to calcite. The apparent order found from kinetics data was n>2, thus suggesting a surface nucleation mechanism.

  19. High aerosol acidity despite declining atmospheric sulfate concentrations over the past 15 years

    NASA Astrophysics Data System (ADS)

    Weber, Rodney J.; Guo, Hongyu; Russell, Armistead G.; Nenes, Athanasios

    2016-04-01

    Particle acidity affects aerosol concentrations, chemical composition and toxicity. Sulfate is often the main acid component of aerosols, and largely determines the acidity of fine particles under 2.5 μm in diameter, PM2.5. Over the past 15 years, atmospheric sulfate concentrations in the southeastern United States have decreased by 70%, whereas ammonia concentrations have been steady. Similar trends are occurring in many regions globally. Aerosol ammonium nitrate concentrations were assumed to increase to compensate for decreasing sulfate, which would result from increasing neutrality. Here we use observed gas and aerosol composition, humidity, and temperature data collected at a rural southeastern US site in June and July 2013 (ref. ), and a thermodynamic model that predicts pH and the gas-particle equilibrium concentrations of inorganic species from the observations to show that PM2.5 at the site is acidic. pH buffering by partitioning of ammonia between the gas and particle phases produced a relatively constant particle pH of 0-2 throughout the 15 years of decreasing atmospheric sulfate concentrations, and little change in particle ammonium nitrate concentrations. We conclude that the reductions in aerosol acidity widely anticipated from sulfur reductions, and expected acidity-related health and climate benefits, are unlikely to occur until atmospheric sulfate concentrations reach near pre-anthropogenic levels.

  20. Insights Into the Aqueous History of Mars from Acid-Sulfate Weathered Phyllosilicates

    NASA Technical Reports Server (NTRS)

    Craig, P. I.; Ming, D. W.; Rampe, E. B.; Morris, R. V.

    2016-01-01

    Phyllosilicates on Mars are thought to have formed during Mars' earliest Noachian geologic era (approx. 4.1-3.7 Ga). Sulfate formation, on the other hand, requires more acidic conditions which are thought to have occurred later during Mars' Hesperian era (approx. 3.7-3.0 Ga). Therefore, regions on Mars where phyllosilicates and sulfates are found in close proximity to each other provide evidence for the aqueous conditions during this global transition. Both phyllosilicates and sulfates form in the presence of water and thus give clues to the aqueous history of Mars and its potential for habitability. Phyllosilicates that formed during the Noachian era would have been weathered by the prevailing acidic conditions that define the Hesperian. Therefore, the purpose of this study is to characterize the alteration products of acid-sulfate weathered phyllosilicates in laboratory experiments, focusing on the Fe/Mg-smectites commonly identified on Mars. We also compare our results to observations of phyllosilicates and sulfates on Mars in regions such as Endeavour Crater and Mawrth Vallis to understand the formation process of sulfates and constrain the aqueous history of these regions.

  1. Sulfate Formation From Acid-Weathered Phylosilicates: Implications for the Aqueous History of Mars

    NASA Technical Reports Server (NTRS)

    Craig, P. I.; Ming, D. W.; Rampe, E. B.

    2014-01-01

    Most phyllosilicates on Mars are thought to have formed during the planet's earliest Noachian era, then Mars underwent a global change making the planet's surface more acidic [e.g. 1]. Prevailing acidic conditions may have affected the already existing phyllosilicates, resulting in the formation of sulfates. Both sulfates and phyllosilicates have been identified on Mars in a variety of geologic settings [2] but only in a handful of sites are these minerals found in close spatial proximity to each other, including Mawrth Vallis [3,4] and Gale Crater [5]. While sulfate formation from the acidic weathering of basalts is well documented in the literature [6,7], few experimental studies investigate sulfate formation from acid-weathered phyllosilicates [8-10]. The purpose of this study is to characterize the al-teration products of acid-weathered phyllosilicates in laboratory experiments. We focus on three commonly identified phyllosilicates on Mars: nontronite (Fe-smectite), saponite (Mg-smectite), and montmorillonite (Al-smectite) [1, and references therein]. This information will help constrain the formation processes of sulfates observed in close association with phyllosilicates on Mars and provide a better understanding of the aqueous history of such regions as well as the planet as a whole.

  2. Effect of dietary aluminum sulfate on calcium and phosphorus metabolism of broiler chicks.

    PubMed

    Hussein, A S; Cantor, A H; Johnson, T H; Yokel, R A

    1990-06-01

    The effect of dietary aluminum sulfate on Ca and P metabolism was studied using 1-day-old male broiler chicks. In Experiment 1, practical diets providing .90% Ca plus .45% available P (Pav), .90% Ca plus .78% Pav, 1.80% Ca plus .45% Pav, or 1.80% Ca plus .90% Pav were fed with 0 or .392% A1 as aluminum sulfate for 21 days. The control diet (.90% Ca plus .45% Pav) without added A1 was fed to all chicks during Days 22 to 49. In general, A1 significantly (P less than .05) decreased BW gain, feed intake, gain:feed ratio, plasma inorganic P (Pi), tibia breaking strength, tibia weight, percentage of tibia ash, and plasma Zn, measured at Day 21. Elevating Pav increased BW gain, feed intake, gain:feed ratio, tibia weight and plasma Zn, and decreased plasma total Ca in the presence of .392% A1 plus 1.80% Ca. Plasma Pi, tibia breaking strength, and percentage of tibia ash were increased by raising dietary Pav in the presence of .392% A1 with either level of Ca. Negative effects of dietary A1 on feed intake and BW persisted through Day 49. In Experiment 2, a control diet (.90% Ca, .45% Pav) was fed for ad libitum access either alone or supplemented with .2% A1 as aluminum sulfate or with an equivalent amount of sulfate provided by potassium sulfate. The control diet was also pair-fed to chicks given .2% A1. Dietary A1 significantly depressed weight gain, feed intake, gain:feed ratio, and plasma Pi.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Fatty acids, calcium soaps of fatty acids, and cottonseeds fed to high yielding cows.

    PubMed

    Sklan, D; Ashkenazi, R; Braun, A; Devorin, A; Tabori, K

    1992-09-01

    We examined the effects of dietary fat as cottonseed, fatty acids, or calcium soaps of fatty acids in the rations of high yielding lactating cows receiving low forage. Experiments were with isoenergetic, isonitrogenous diets containing equal amounts of forage. Inclusion of up to 510 g/d of fatty acids in the ration enhanced FCM yield. With cottonseed, increased FCM was mainly due to increased fat yield. Dietary fatty acids tended to increase milk in mid and late lactation and to decrease fat percentage. Calcium soaps of fatty acids enhanced FCM, particularly in early lactation. Feeding cottonseed and fatty acids together did not enhance yield. Effects described may be attributed in part to changes in ruminal fermentation in which cottonseed increased acetate concentrations and fatty acids decreased the ratio of acetate and butyrate to propionate and in part to enhanced efficiency of milk yield when fat was included in the ration.

  4. Phytic acid plus calcium, but not phytic acid alone, decreases fluoride bioavailability in the rat

    SciTech Connect

    Cerklewski, F.L. )

    1991-03-15

    Results of in vitro studies have suggested that fluoride becomes insoluble when some soy-based infant formulas are diluted with fluoridated water because of the presence of phytate, added calcium or a combination of these factors. The present study was designed to test this hypothesis in vivo. Male albino rats were fed a purified diet containing phytic acid, calcium and fluoride for 4 weeks in a factorial design of treatments. Phytic acid was added to the diet by chemically reacting a phytic acid concentrate with casein prior to diet preparation to mimic a soy-protein. Food intake, weight gain and femur P were unaffected by dietary treatments. Both phytic acid and supplemental calcium alone had little or no effect upon fluoride uptake into either bone or teeth. The combination of phytic acid plus supplemental calcium, however, significantly increased % of fluoride intake found in the feces which was reflected in a significant decrease in fluoride concentration of femur, 2nd molar teeth and vertebrate bone. These results provide evidence that insoluble complex formation produced by a calcium and phytate interaction can explain reduced fluoride solubility in some soy-based infant formulas as well as decreased fluoride absorbability in vivo.

  5. Identifying sources of acidity and spatial distribution of acid sulfate soils in the Anglesea River catchment, southern Australia

    NASA Astrophysics Data System (ADS)

    Wong, Vanessa; Yau, Chin; Kennedy, David

    2015-04-01

    Globally, coastal and estuarine floodplains are frequently underlain by sulfidic sediments. When exposed to oxygen, sulfidic sediments oxidise to form acid sulfate soils, adversely impacting on floodplain health and adjacent aquatic ecoystems. In eastern Australia, our understanding of the formation of these coastal and estuarine floodplains, and hence, spatial distribution of acid sulfate soils, is relatively well established. These soils have largely formed as a result of sedimentation of coastal river valleys approximately 6000 years BP when sea levels were one to two metres higher. However, our understanding of the evolution of estuarine systems and acid sulfate soil formation, and hence, distribution, in southern Australia remains limited. The Anglesea River, in southern Australia, is subjected to frequent episodes of poor water quality and low pH resulting in closure of the river and, in extreme cases, large fish kill events. This region is heavily reliant on tourism and host to a number of iconic features, including the Great Ocean Road and Twelve Apostles. Poor water quality has been linked to acid leakage from mining activities and Tertiary-aged coal seams, peat swamps and acid sulfate soils in the region. However, our understanding of the sources of acidity and distribution of acid sulfate soils in this region remains poor. In this study, four sites on the Anglesea River floodplain were sampled, representative of the main vegetation communities. Peat swamps and intertidal marshes were both significant sources of acidity on the floodplain in the lower catchment. However, acid neutralising capacity provided by carbonate sands suggests that there are additional sources of acidity higher in the catchment. This pilot study has highlighted the complexity in the links between the floodplain, upper catchment and waterways with further research required to understand these links for targeted acid management strategies.

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

    NASA Technical Reports Server (NTRS)

    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.

  7. Production of fired construction brick from high sulfate-containing fly ash with boric acid addition.

    PubMed

    Başpinar, M Serhat; Kahraman, Erhan; Görhan, Gökhan; Demir, Ismail

    2010-01-01

    The increase of power plant capacity has led to the production of an increasing amount of fly ash that causes high environmental impact in Turkey. Some of the fly ash is utilized within the fired brick industry but high sulfate-containing fly ash creates severe problems during sintering of the fired brick. This study attempted to investigate the potential for converting high sulfate-containing fly ash into useful material for the construction industry by the addition of boric acid. The chemical and mineralogical composition of fly ash and clay were investigated. Boric acid (H(3)BO(3)) was added to fly ash-clay mixtures with up to 5 wt.%. Six different series of test samples were produced by uniaxial pressing. The samples were fired at the industrial clay-brick firing temperatures of 800, 900 and 1000 degrees C. The microstructures of the fired samples were investigated by scanning electron microscopy and some physical and mechanical properties were measured. It was concluded that the firing at conventional brick firing temperature of high sulfate fly ash without any addition of boric acid resulted in very weak strength bricks. The addition of boric acid and clay simultaneously to the high sulfate- containing fly ash brick dramatically increased the compressive strength of the samples at a firing temperature of 1000 degrees C by modifying the sintering behaviour of high sulfate fly ash.

  8. Production of fired construction brick from high sulfate-containing fly ash with boric acid addition.

    PubMed

    Başpinar, M Serhat; Kahraman, Erhan; Görhan, Gökhan; Demir, Ismail

    2010-01-01

    The increase of power plant capacity has led to the production of an increasing amount of fly ash that causes high environmental impact in Turkey. Some of the fly ash is utilized within the fired brick industry but high sulfate-containing fly ash creates severe problems during sintering of the fired brick. This study attempted to investigate the potential for converting high sulfate-containing fly ash into useful material for the construction industry by the addition of boric acid. The chemical and mineralogical composition of fly ash and clay were investigated. Boric acid (H(3)BO(3)) was added to fly ash-clay mixtures with up to 5 wt.%. Six different series of test samples were produced by uniaxial pressing. The samples were fired at the industrial clay-brick firing temperatures of 800, 900 and 1000 degrees C. The microstructures of the fired samples were investigated by scanning electron microscopy and some physical and mechanical properties were measured. It was concluded that the firing at conventional brick firing temperature of high sulfate fly ash without any addition of boric acid resulted in very weak strength bricks. The addition of boric acid and clay simultaneously to the high sulfate- containing fly ash brick dramatically increased the compressive strength of the samples at a firing temperature of 1000 degrees C by modifying the sintering behaviour of high sulfate fly ash. PMID:19423597

  9. Sulfate, chloride and fluoride retention in Andosols exposed to volcanic acid emissions.

    PubMed

    Delmelle, Pierre; Delfosse, Thomas; Delvaux, Bruno

    2003-01-01

    The continuous emissions of SO(2), HCl and HF by Masaya volcano, Nicaragua, represent a substantial source of atmospheric S-, Cl- and F-containing acid inputs for local ecosystems. We report on the effects of such acid depositions on the sulfate, chloride and fluoride contents in soils (0-40 cm) from two distinct transects located downwind from the volcano. The first transect corresponds to relatively undifferentiated Vitric Andosols, and the second transect to more weathered Eutric Andosols. These soils are exposed to various rates of volcanogenic acid addition, with the Vitric sites being generally more affected. Prolonged acid inputs have led to a general pH decrease and reduced exchangeable base cation concentrations in the Andosols. The concentrations of 0.5 M NH(4)F- and 0.016 M KH(2)PO(4)-extractable sulfate (NH(4)F-S and KH(2)PO(4)-S, respectively) indicate that volcanic S addition has increased the inorganic sulfate content of the Vitric and Eutric soils at all depths. In this process, the rate of sulfate accumulation is also dependent on soil allophane contents. For all soils, NH(4)F extracted systematically more (up to 40 times) sulfate than KH(2)PO(4). This difference suggests sulfate incorporation into an aluminum hydroxy sulfate phase, whose contribution to total inorganic sulfate in the Vitric and Eutric Andosols is estimated from approximately 34 to 95% and approximately 65 to 98%, respectively. The distribution of KH(2)PO(4)-extractable chloride in the Vitric and Eutric Andosols exposed to volcanic Cl inputs reveals that added chloride readily migrates through the soil profiles. In contrast, reaction of fluoride with Al and Fe oxyhydroxides and allophanes is an important sink mechanism in the Masaya Andosols exposed to airborne volcanic F. Fluoride dominates the anion distribution in all soil horizons, although F is the least concentrated element in the volcanic emissions and depositions. The soil anion distribution reflects preferential retention

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

    PubMed

    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

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

    SciTech Connect

    Gooding, J.L.; Wentworth, S.J.; Zolensky, M.E. )

    1988-04-01

    Two varieties of Ca-carbonate were found in a total of three interior (>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 magnesium and phosphorus, 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 {mu}m, anhedral grains of nearly pure CaCO{sub 3} and was intimately associated with laths and needles of Ca-sulfate (possibly gypsum). The coexisting carbonate and sulfate appeared to be partially decrepitated, relict grains that were trapped during rapid solidification of quench-textured pyroxene and glass. For at least the latter occurrence, textural relationships clearly indicate a pre-terrestrial origin for the salts. All evidence considered, it is probably that both varieties of Ca-carbonate (and the Ca-sulfate) formed on a planetary body (probably Mars) before the meteorite fell on Earth.

  12. Acid Sulfate Weathering on Mars: Results from the Mars Exploration Rover Mission

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W.; Morris, R. V.; Golden, D. C.

    2006-01-01

    Sulfur has played a major role in the formation and alteration of outcrops, rocks, and soils at the Mars Exploration Rover landing sites on Meridiani Planum and in Gusev crater. Jarosite, hematite, and evaporite sulfates (e.g., Mg and Ca sulfates) occur along with siliciclastic sediments in outcrops at Meridiani Planum. The occurrence of jarosite is a strong indicator for an acid sulfate weathering environment at Meridiani Planum. Some outcrops and rocks in the Columbia Hills in Gusev crater appear to be extensively altered as suggested by their relative softness as compared to crater floor basalts, high Fe(3+)/FeT, iron mineralogy dominated by nanophase Fe(3+) oxides, hematite and/or goethite, corundum-normative mineralogies, and the presence of Mg- and Casulfates. One scenario for aqueous alteration of these rocks and outcrops is that vapors and/or fluids rich in SO2 (volcanic source) and water interacted with rocks that were basaltic in bulk composition. Ferric-, Mg-, and Ca-sulfates, phosphates, and amorphous Si occur in several high albedo soils disturbed by the rover's wheels in the Columbia Hills. The mineralogy of these materials suggests the movement of liquid water within the host material and the subsequent evaporation of solutions rich in Fe, Mg, Ca, S, P, and Si. The presence of ferric sulfates suggests that these phases precipitated from highly oxidized, low-pH solutions. Several hypotheses that invoke acid sulfate weathering environments have been suggested for the aqueous formation of sulfate-bearing phases on the surface of Mars including (1) the oxidative weathering of ultramafic igneous rocks containing sulfides; (2) sulfuric acid weathering of basaltic materials by solutions enriched by volcanic gases (e.g., SO2); and (3) acid fog (i.e., vapors rich in H2SO4) weathering of basaltic or basaltic-derived materials.

  13. Lactose behaviour in the presence of lactic acid and calcium.

    PubMed

    Wijayasinghe, Rangani; Vasiljevic, Todor; Chandrapala, Jayani

    2016-08-01

    Physical properties of lactose appeared influenced by presence of lactic acid in the system. Some other components such as Ca may further attenuate lactose behaviour and impact its phase transition. A model-based study was thus implemented with varying concentrations of Ca (0·12, 0·072 or 0·035% w/w) and lactic acid (0·05, 0·2, 0·4 or 1% w/w) in establishing the effects of these two main acid whey constituents on lactose phase behaviour. Concentrated solutions (50% w/w) containing lactose, lactic acid and Ca were analysed for thermal behaviour and structural changes by Differential Scanning Colorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR), respectively. Presence of 1% (w/w) lactic acid and 0·12% (w/w) Ca in lactose solution significantly increased the evaporation enthalpy of water, delayed and increased the energy required for lactose crystallisation as compared to pure lactose. FTIR analysis indicated a strong hydration layer surrounding lactose molecules, restricting water mobility and/or inducing structural changes of lactose, hindering its crystallisation. The formation of calcium lactate, which restricts the diffusion of lactose molecules, is also partly responsible. It appears that Ca removal from acid whey may be a necessary step in improving the processability of acid whey. PMID:27600977

  14. Stabilization of human prostatic acid phosphatase by coupling with chondroitin sulfate.

    PubMed

    Luchter-Wasylewska, E; Dulińska, J; Ostrowski, W S; Torchilin, V P; Trubetskoy, V S

    1991-02-01

    Human prostatic acid phosphatase (PAP) (EC 3.1.3.2) was covalently linked to chondroitin sulfate A from whale cartilage. In order to bind the protein amino groups with the preactivated carboxyl groups of chondroitin sulfate, 1-ethyl-3-(3'-dimethylaminepropyl)carbodiimide and N-hydroxysulfosuccinimide were used as coupling agents. The product was soluble and enzymatically active. The activity was on average 25% higher than that of the free enzyme. The product was heterogeneous in respect to charge and Mr (50-1500) kDa, as determined by chromatography on Sephacryl S 300 and polyacrylamide gel electrophoresis. The resulting polymers contained covalently bound chondroitin sulfate, as shown by the biotin-avidin test. The modified enzyme is more resistant against various denaturing agents, e.g., urea, ethanol, and heat. Thus covalent modification of PAP by cross-linking to chondroitin sulfate could be the preferred method for stabilization of its biological activity.

  15. Calcium ion binding to a soil fulvic acid using a donnan potential model

    USGS Publications Warehouse

    Marinsky, J.A.; Mathuthu, A.; Ephraim, J.H.; Reddy, M.M.

    1999-01-01

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

  16. Soil-calcium depletion linked to acid rain and forest growth in the eastern United States

    USGS Publications Warehouse

    Lawrence, Gregory B.; Huntington, T.G.

    1999-01-01

    Since the discovery of acid rain in the 1970's, scientists have been concerned that deposition of acids could cause depletion of calcium in forest soils. Research in the 1980's showed that the amount of calcium in forest soils is controlled by several factors that are difficult to measure. Further research in the 1990's, including several studies by the U.S. Geological Survey, has shown that (1) calcium in forest soils has decreased at locations in the northeastern and southeastern U.S., and (2) acid rain and forest growth (uptake of calcium from the soil by roots) are both factors contributing to calcium depletion.

  17. Interactions between red light, abscisic acid, and calcium in gravitropism

    NASA Technical Reports Server (NTRS)

    Leopold, A. C.; LaFavre, A. K.

    1989-01-01

    The effect of red light on orthogravitropism of Merit corn (Zea mays L.) roots has been attributed to its effects on the transduction phase of gravitropism (AC Leopold, SH Wettlaufer [1988] Plant Physiol 87:803-805). In an effort to characterize the orthogravitropic transduction system, comparative experiments have been carried out on the effects of red light, calcium, and abscisic acid (ABA). The red light effect can be completely satisfied with added ABA (100 micromolar) or with osmotic shock, which is presumed to increase endogenous ABA. The decay of the red light effect is closely paralleled by the decay of the ABA effect. ABA and exogenous calcium show strong additive effects when applied to either Merit or a line of corn which does not require red light for orthogravitropism. Measurements of the ABA content show marked increases in endogenous ABA in the growing region of the roots after red light. The interpretation is offered that red light or ABA may serve to increase the cytoplasmic concentrations of calcium, and that this may be an integral part of orthogravitropic transduction.

  18. Impacts of Sulfate Seed Acidity and Water Content on Isoprene Secondary Organic Aerosol Formation.

    PubMed

    Wong, Jenny P S; Lee, Alex K Y; Abbatt, Jonathan P D

    2015-11-17

    The effects of particle-phase water and the acidity of pre-existing sulfate seed particles on the formation of isoprene secondary organic aerosol (SOA) was investigated. SOA was generated from the photo-oxidation of isoprene in a flow tube reactor at 70% relative humidity (RH) and room temperature in the presence of three different sulfate seeds (effloresced and deliquesced ammonium sulfate and ammonium bisulfate) under low NOx conditions. High OH exposure conditions lead to little isoprene epoxydiol (IEPOX) SOA being generated. The primary result is that particle-phase water had the largest effect on the amount of SOA formed, with 60% more SOA formation occurring with deliquesced ammonium sulfate seeds as compared to that on effloresced ones. The additional organic material was highly oxidized. Although the amount of SOA formed did not exhibit a dependence on the range of seed particle acidity examined, perhaps because of the low amount of IEPOX SOA, the levels of high-molecular-weight material increased with acidity. While the uptake of organics was partially reversible under drying, the results nevertheless indicate that particle-phase water enhanced the amount of organic aerosol material formed and that the RH cycling of sulfate particles may mediate the extent of isoprene SOA formation in the atmosphere. PMID:26460477

  19. In vitro/in vivo comparison of cefuroxime release from poly(ε-caprolactone)-calcium sulfate implants for osteomyelitis treatment.

    PubMed

    Yaprakci, Volkan; Erdemli, Ozge; Kayabolen, Alisan; Tezcaner, Aysen; Bozkurt, Fatih; Keskin, Dilek

    2013-01-01

    This study aimed to investigate the release of cefuroxime axetil (CF) and calcium from poly(ε-caprolactone) (PCL)-calcium sulfate (CaS) implants (PCL:CaS 2:1-10% CF; PCL:CaS 2:1-20% CF; PCL:CaS 1:1-10% CF) for treating infectious bone diseases. Bioactivity, crystallinity and strength, and release profiles under standard and pressurized release conditions were studied. PCL:CaS 2:1-20% CF had slower release than 10% loading. These groups had no significant change in CF and Ca release in response to pressure. The PCL:CaS 1:1 group had the slowest release despite having higher CaS, probably due to more compaction of discs. In contrast, pressure caused significant differentiation of CF and Ca(2+) release. The presence of CaS enhanced mechanical properties and bioactivity of discs. SEM and XPS results showed calcium-phosphate containing accumulations on surfaces upon SBF incubation. CF-loaded implants were applied in a rabbit osteomyelitis model. In vivo CF release was enhanced with increased CaS proportions, suggesting that in vivo release conditions are closer to pressurized in vitro conditions. In the control group, there was still some inflammation in the bone and no complete coverage with bone was achieved in the defect site. Discs provided a suitable surface for regeneration of bone. However, bone formation in the PCL:CaS 1:1 disc implanted group was more complete and regular than in the 2:1 group.

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

    SciTech Connect

    Zhang, Y.; Sun, W.; Shang, L.

    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.

  1. Microbial sulfate reduction under sequentially acidic conditions in an upflow anaerobic packed bed bioreactor.

    PubMed

    Jong, Tony; Parry, David L

    2006-07-01

    The aim of this study was to operate an upflow anaerobic packed bed reactor (UAPB) containing sulfate reducing bacteria (SRB) under acidic conditions similar to those found in acid mine drainage (AMD). The UAPB was filled with sand and operated under continuous flow at progressively lower pH and was shown to be capable of supporting sulfate reduction at pH values of 6.0, 5.0, 4.5, 4.0 and 3.5 in a synthetic medium containing 53.5 mmol l(-1) lactate. Sulfate reduction rates of 553-1,052 mmol m(-3) d(-1) were obtained when the influent solution pH was progressively lowered from pH 6.0 to 4.0, under an optimal flow rate of 2.61 ml min(-1). When the influent pH was further lowered to pH 3.5, sulfate reduction was substantially reduced with only about 1% sulfate removed at a rate of 3.35 mmol m(-3) d(-1) after 20 days of operation. However, viable SRB were recovered from the column, indicating that the SRB population was capable of surviving and metabolizing at low levels even at pH 3.5 conditions for at least 20 days. The changes in conductivity in the SRB column did not always occur with changes in pH and redox potential, suggesting that conductivity measurements may be more sensitive to SRB activity and could be used as an additional tool for monitoring SRB activity. The bioreactor containing SRB was able to reduce sulfate and generate alkalinity even when challenged with influent as low as pH 3.5, indicating that such treatment systems have potential for bioremediating highly acidic, sulfate contaminated waste waters.

  2. Intercommunity differences in acid aerosol (H+)/sulfate (SO4(2-) ratios.

    PubMed

    Ozkaynak, H; Xue, J; Zhou, H; Spengler, J D; Thurston, G D

    1996-01-01

    Exposures to acid aerosols have been associated with acute and chronic health effects. Beginning in 1988, extensive monitoring of acid aerosols (H+), sulfates (SO4(2-)), and ammonia (NH3) was conducted in 24 communities in the United States and Canada in order to characterize the seasonal and daily variations of these pollutants. More recently, in 1992 and 1993, summer monitoring of the same pollutants was conducted by Harvard researchers at multiple locations in Philadelphia, Pennsylvania to examine the factors causing spatial variation in the acidity levels in the greater metropolitan Philadelphia area. Earlier, a similar study also was conducted by Harvard in a more rural community, State College, Ohio, providing data on acidity, sulfate, and ammonia levels. In addition to these studies, New York University researchers have gathered substantial data on aerosol acidity, sulfates, and NH3 levels from sites in the New York City metropolitan region, Albany, Buffalo, and the Toronto metropolitan region between 1988 and 1992. This paper examines the relationships among H+, SO4(2-), ozone, and population density using summer measurements from sites in 24 cities across the United States and Canada, as well as Philadelphia, State College, the New York City region, Buffalo, and Albany. While past studies have consistently shown that H+ and SO4(2-) are correlated over time at sites in eastern North America, the results of our analysis show that spatial variations in the ratios of mean acid-to-sulfate levels also can be predicted satisfactorily with the use of either a linear or a quadratic model, once variations in population density are addressed (R2 = 0.6). These models may be useful in retrospective epidemiological investigations of acid aerosol exposures and health effects, using widely available sulfate measurements and data on local population size.

  3. 40 CFR 721.10382 - Diphosphoric acid, calcium salt (1:1).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Diphosphoric acid, calcium salt (1:1... Specific Chemical Substances § 721.10382 Diphosphoric acid, calcium salt (1:1). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as diphosphoric acid,...

  4. Printability of calcium phosphate: calcium sulfate powders for the application of tissue engineered bone scaffolds using the 3D printing technique.

    PubMed

    Zhou, Zuoxin; Buchanan, Fraser; Mitchell, Christina; Dunne, Nicholas

    2014-05-01

    In this study, calcium phosphate (CaP) powders were blended with a three-dimensional printing (3DP) calcium sulfate (CaSO4)-based powder and the resulting composite powders were printed with a water-based binder using the 3DP technology. Application of a water-based binder ensured the manufacture of CaP:CaSO4 constructs on a reliable and repeatable basis, without long term damage of the printhead. Printability of CaP:CaSO4 powders was quantitatively assessed by investigating the key 3DP process parameters, i.e. in-process powder bed packing, drop penetration behavior and the quality of printed solid constructs. Effects of particle size, CaP:CaSO4 ratio and CaP powder type on the 3DP process were considered. The drop penetration technique was used to reliably identify powder formulations that could be potentially used for the application of tissue engineered bone scaffolds using the 3DP technique. Significant improvements (p<0.05) in the 3DP process parameters were found for CaP (30-110 μm):CaSO4 powders compared to CaP (<20 μm):CaSO4 powders. Higher compressive strength was obtained for the powders with the higher CaP:CaSO4 ratio. Hydroxyapatite (HA):CaSO4 powders showed better results than beta-tricalcium phosphate (β-TCP):CaSO4 powders. Solid and porous constructs were manufactured using the 3DP technique from the optimized CaP:CaSO4 powder formulations. High-quality printed constructs were manufactured, which exhibited appropriate green compressive strength and a high level of printing accuracy. PMID:24656346

  5. Printability of calcium phosphate: calcium sulfate powders for the application of tissue engineered bone scaffolds using the 3D printing technique.

    PubMed

    Zhou, Zuoxin; Buchanan, Fraser; Mitchell, Christina; Dunne, Nicholas

    2014-05-01

    In this study, calcium phosphate (CaP) powders were blended with a three-dimensional printing (3DP) calcium sulfate (CaSO4)-based powder and the resulting composite powders were printed with a water-based binder using the 3DP technology. Application of a water-based binder ensured the manufacture of CaP:CaSO4 constructs on a reliable and repeatable basis, without long term damage of the printhead. Printability of CaP:CaSO4 powders was quantitatively assessed by investigating the key 3DP process parameters, i.e. in-process powder bed packing, drop penetration behavior and the quality of printed solid constructs. Effects of particle size, CaP:CaSO4 ratio and CaP powder type on the 3DP process were considered. The drop penetration technique was used to reliably identify powder formulations that could be potentially used for the application of tissue engineered bone scaffolds using the 3DP technique. Significant improvements (p<0.05) in the 3DP process parameters were found for CaP (30-110 μm):CaSO4 powders compared to CaP (<20 μm):CaSO4 powders. Higher compressive strength was obtained for the powders with the higher CaP:CaSO4 ratio. Hydroxyapatite (HA):CaSO4 powders showed better results than beta-tricalcium phosphate (β-TCP):CaSO4 powders. Solid and porous constructs were manufactured using the 3DP technique from the optimized CaP:CaSO4 powder formulations. High-quality printed constructs were manufactured, which exhibited appropriate green compressive strength and a high level of printing accuracy.

  6. Algae as an electron donor promoting sulfate reduction for the bioremediation of acid rock drainage.

    PubMed

    Ayala-Parra, Pedro; Sierra-Alvarez, Reyes; Field, Jim A

    2016-11-01

    This study assessed bioremediation of acid rock drainage in simulated permeable reactive barriers (PRB) using algae, Chlorella sorokiniana, as the sole electron donor for sulfate-reducing bacteria. Lipid extracted algae (LEA), the residues of biodiesel production, were compared with whole cell algae (WCA) as an electron donor to promote sulfate-reducing activity. Inoculated columns containing anaerobic granular sludge were fed a synthetic medium containing H2SO4 and Cu(2+). Sulfate, sulfide, Cu(2+) and pH were monitored throughout the experiment of 123d. Cu recovered in the column packing at the end of the experiment was evaluated using sequential extraction. Both WCA and LEA promoted 80% of sulfate removal (12.7mg SO4(2-) d(-1)) enabling near complete Cu removal (>99.5%) and alkalinity generation raising the effluent pH to 6.5. No noteworthy sulfate reduction, alkalinity formation and Cu(2+) removal were observed in the endogenous control. In algae amended-columns, Cu(2+) was precipitated with biogenic H2S produced by sulfate reduction. Formation of CuS was evidenced by sequential extraction and X-ray diffraction. LEA and WCA provided similar levels of electron donor based on the COD balance. The results demonstrate an innovative passive remediation system using residual algae biomass from the biodiesel industry.

  7. Algae as an electron donor promoting sulfate reduction for the bioremediation of acid rock drainage.

    PubMed

    Ayala-Parra, Pedro; Sierra-Alvarez, Reyes; Field, Jim A

    2016-11-01

    This study assessed bioremediation of acid rock drainage in simulated permeable reactive barriers (PRB) using algae, Chlorella sorokiniana, as the sole electron donor for sulfate-reducing bacteria. Lipid extracted algae (LEA), the residues of biodiesel production, were compared with whole cell algae (WCA) as an electron donor to promote sulfate-reducing activity. Inoculated columns containing anaerobic granular sludge were fed a synthetic medium containing H2SO4 and Cu(2+). Sulfate, sulfide, Cu(2+) and pH were monitored throughout the experiment of 123d. Cu recovered in the column packing at the end of the experiment was evaluated using sequential extraction. Both WCA and LEA promoted 80% of sulfate removal (12.7mg SO4(2-) d(-1)) enabling near complete Cu removal (>99.5%) and alkalinity generation raising the effluent pH to 6.5. No noteworthy sulfate reduction, alkalinity formation and Cu(2+) removal were observed in the endogenous control. In algae amended-columns, Cu(2+) was precipitated with biogenic H2S produced by sulfate reduction. Formation of CuS was evidenced by sequential extraction and X-ray diffraction. LEA and WCA provided similar levels of electron donor based on the COD balance. The results demonstrate an innovative passive remediation system using residual algae biomass from the biodiesel industry. PMID:27318730

  8. Injectable hydrogels derived from phosphorylated alginic acid calcium complexes.

    PubMed

    Kim, Han-Sem; Song, Minsoo; Lee, Eun-Jung; Shin, Ueon Sang

    2015-06-01

    Phosphorylation of sodium alginate salt (NaAlg) was carried out using H3PO4/P2O5/Et3PO4 followed by acid-base reaction with Ca(OAc)2 to give phosphorylated alginic acid calcium complexes (CaPAlg), as a water dispersible alginic acid derivative. The modified alginate derivatives including phosphorylated alginic acid (PAlg) and CaPAlg were characterized by nuclear magnetic resonance spectroscopy for (1)H, and (31)P nuclei, high resolution inductively coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. CaPAlg hydrogels were prepared simply by mixing CaPAlg solution (2w/v%) with NaAlg solution (2w/v%) in various ratios (2:8, 4:6, 6:4, 8:2) of volume. No additional calcium salts such as CaSO4 or CaCl2 were added externally. The gelation was completed within about 3-40min indicating a high potential of hydrogel delivery by injection in vivo. Their mechanical properties were tested to be ≤6.7kPa for compressive strength at break and about 8.4kPa/mm for elastic modulus. SEM analysis of the CaPAlg hydrogels showed highly porous morphology with interconnected pores of width in the range of 100-800μm. Cell culture results showed that the injectable hydrogels exhibited comparable properties to the pure alginate hydrogel in terms of cytotoxicity and 3D encapsulation of cells for a short time period. The developed injectable hydrogels showed suitable physicochemical and mechanical properties for injection in vivo, and could therefore be beneficial for the field of soft tissue engineering. PMID:25842118

  9. Acid sulfate soils and human health--a Millennium Ecosystem Assessment.

    PubMed

    Ljung, Karin; Maley, Fiona; Cook, Angus; Weinstein, Philip

    2009-11-01

    Acid sulfate soils have been described as the "nastiest soils on earth" because of their strong acidity, increased mobility of potentially toxic elements and limited bioavailability of nutrients. They only cover a small area of the world's total problem soils, but often have significant adverse effects on agriculture, aquaculture and the environment on a local scale. Their location often coincides with high population density areas along the coasts of many developing countries. As a result, their negative impacts on ecosystems can have serious implications to those least equipped for coping with the low crop yields and reduced water quality that can result from acid sulfate soil disturbance. The Millennium Ecosystem Assessment called on by the United Nations in 2000 emphasised the importance of ecosystems for human health and well-being. These include the service they provide as sources of food and water, through the control of pollution and disease, as well as for the cultural services ecosystems provide. While the problems related to agriculture, aquaculture and the environment have been the focus of many acid sulfate soil management efforts, the connection to human health has largely been ignored. This paper presents the potential health issues of acid sulfate soils, in relation to the ecosystem services identified in the Millennium Ecosystem Assessment. It is recognised that significant implications on food security and livelihood can result, as well as on community cohesiveness and the spread of vector-borne disease. However, the connection between these outcomes and acid sulfate soils is often not obvious and it is therefore argued that the impact of such soils on human well-being needs to be recognised in order to raise awareness among the public and decision makers, to in turn facilitate proper management and avoid potential human ill-health.

  10. Purification and properties of bile acid sulfate sulfatase from Pseudomonas testosteroni.

    PubMed

    Tazuke, Y; Matsuda, K; Adachi, K; Tsukada, Y

    1994-05-01

    The bile acid sulfate sulfatase (BSS) produced by Pseudomonas testosteroni was purified and characterized. Chromatofocusing behavior and amino acid sequence over twelve amino acid residues from N-terminus of the enzyme indicated that BSS was composed of two isoforms of which molecular weights were 125,000 and 103,000. Each isoform was a homodimer of a subunit of which molecular weight was 53,000 or 51,000, respectively. The optimum pH was 8.5 and BSS was stable at pH 5.8-8.0. The thermostability above 32 degrees C was improved by the addition of polyols, such as sorbitol, sucrose, and glycerol. BSS was a Mn(2+)-dependent enzyme and contained 1-2 atoms of manganese in its own protein molecule. All 3 alpha-sulfate esters of the bile acids routinely appearing in human serum were hydrolyzed by BSS to 3 beta-hydroxyl iso-compounds corresponding to each bile acid and sulfuric acid. We tentatively named this novel enzyme BSS (bile acid 3 alpha-sulfate sulfohydrolase). PMID:7764976

  11. Measurement of partial vapor pressure of ammonia over acid ammonium sulfate solutions by an integral method

    NASA Astrophysics Data System (ADS)

    Koutrakis, P.; Aurian-BlǎJeni, B.

    1993-02-01

    We present a simple, integral, passive method for measuring partial vapor pressure. Integral methods are useful tools when dealing with very low concentrations because collection over extended periods increases the analytical sensitivity. Passive methods have the advantage of not introducing constraints external to the system. The principle of the method used here is to selectively react the substance in the atmosphere over a solution with an immobilized coating on an appropriate support. The reaction product is not volatile, but is soluble and can be extracted in an appropriate solvent and analyzed. The method has been applied to measuring the vapor pressure of ammonia over aqueous solutions. The vapor pressure over ammonium sulfate solutions depends on the acidity of the solutions as well as on the salt concentration. The dependence can be explained with a simple model. Furthermore, using the same model, we calculated the ammonia vapor pressure above different ammonium sulfate/sulfuric acid aqueous solutions as a function of sulfate molarity and percentage of sulfuric acid. The results from the calculations suggest that for ambient ammonia concentrations less than 10 ppb, acid sulfate aerosols are not completely neutralized.

  12. The effect of copper sulfate, potassium permanganate, and peracetic acid on Ichthyobodo necator in channel catfish

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ichthyobodo necator is a single celled biflagellate that can cause significant mortalities in fish, particularly young, tank-reared fish. Copper sulfate (CuSO4), potassium permanganate (KMnO4) and peracetic acid (PAA) were evaluated for effectiveness against Ichthybodosis in juvenile channel catfis...

  13. Use of copper sulfate and peracetic acid as therapeutants on fish: can these replace formalin?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Copper sulfate (CuSO4) and peracetic acid (PAA) are compounds that have been found to be useful in several areas of aquaculture around the world. In the United States, CuSO4 is used for treatment of an ectoparasite (Ichthyophthirius multifiliis) on fish (Straus 1993; Tieman and Goodwin 2001), and s...

  14. Mine Waste Technology Program. In Situ Source Control Of Acid Generation Using Sulfate-Reducing Bacteria

    EPA Science Inventory

    This report summarizes the results of the Mine Waste Technology Program (MWTP) Activity III, Project 3, In Situ Source Control of Acid Generation Using Sulfate-Reducing Bacteria, funded by the U.S. Environmental Protection Agency (EPA) and jointly administered by EPA and the U.S....

  15. 75 FR 51055 - Propionic Acid and Salts, and Urea Sulfate; Registration Review Proposed Decisions; Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-18

    ...This notice announces the availability of EPA's proposed registration review decisions for the pesticides propionic acid and salts, and urea sulfate and opens a public comment period on the proposed decisions. Registration review is EPA's periodic review of pesticide registrations to ensure that each pesticide continues to satisfy the statutory standard for registration, that is, that the......

  16. 75 FR 78243 - Propionic Acid and Salts, Urea Sulfate, Methidathion, and Methyl Parathion; Registration Review...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-15

    ...This notice announces the availability of EPA's final registration review decisions for the pesticides propionic acid and salts, case no. 4078, urea sulfate, case no. 7213, methidathion, case no. 0034, and methyl parathion, case no. 0153. Registration review is EPA's periodic review of pesticide registrations to ensure that each pesticide continues to satisfy the statutory standard for......

  17. 40 CFR 417.130 - Applicability; description of the chlorosulfonic acid sulfation subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 30 2012-07-01 2012-07-01 false Applicability; description of the chlorosulfonic acid sulfation subcategory. 417.130 Section 417.130 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS SOAP AND DETERGENT MANUFACTURING POINT...

  18. 40 CFR 417.120 - Applicability; description of the sulfamic acid sulfation subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 30 2012-07-01 2012-07-01 false Applicability; description of the sulfamic acid sulfation subcategory. 417.120 Section 417.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS SOAP AND DETERGENT MANUFACTURING POINT...

  19. 40 CFR 417.130 - Applicability; description of the chlorosulfonic acid sulfation subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 30 2013-07-01 2012-07-01 true Applicability; description of the chlorosulfonic acid sulfation subcategory. 417.130 Section 417.130 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS SOAP AND DETERGENT MANUFACTURING POINT...

  20. 40 CFR 417.130 - Applicability; description of the chlorosulfonic acid sulfation subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 29 2014-07-01 2012-07-01 true Applicability; description of the chlorosulfonic acid sulfation subcategory. 417.130 Section 417.130 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS SOAP AND DETERGENT MANUFACTURING POINT...

  1. 40 CFR 417.120 - Applicability; description of the sulfamic acid sulfation subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 30 2013-07-01 2012-07-01 true Applicability; description of the sulfamic acid sulfation subcategory. 417.120 Section 417.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS SOAP AND DETERGENT MANUFACTURING POINT...

  2. 40 CFR 417.120 - Applicability; description of the sulfamic acid sulfation subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 29 2014-07-01 2012-07-01 true Applicability; description of the sulfamic acid sulfation subcategory. 417.120 Section 417.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS SOAP AND DETERGENT MANUFACTURING POINT...

  3. Evaporation pathways and solubility of Fe-Ca-Mg-rich salts in acid sulfate waters. A model for Martian ancient surface waters

    NASA Astrophysics Data System (ADS)

    Sobron, P.; Sansano, A.; Sanz, A.

    2011-12-01

    It has been suggested that Martian iron rich sulfate and oxyhydroxide deposits were precipitated from meltwaters[1], thought to have been acidic. Alternatively, iron(III)-rich hydrated sulfates from oxidized sulfides observed in the outcrops may occur as a result of long-term reactions[4]. Recent analysis of Martian materials support that they come from hydrothermal activity[5], which is highly consistent with the observation of enriched in iron, magnesium, silicon and calcium materials[2]. Independently of the nature of the sulfate formation paths on Mars, characterizing the interaction of saline mineral assemblages and the aqueous solutions necessary for their formation is significance in assessing Mars' hydrological and mineralogical evolution history. In this work we have characterized a layered deposit(Fig. 1) formed from the evaporation of stream water from Rio Tinto, Spain, a relevant Mars analog site[6]. The minerals detected in-situ, confirmed later via high resolution laser Raman spectroscopy in the laboratory, are, from bottom to top: (A) mixture of goethite and probably schwermannite; (B) goethite; (C) mixture of gypsum and highly hydrated ferric sulfates; (D) hexahydrite; and (E) mixture of hexahydrite and epsomite. What we observed in this deposit is the precipitation of relatively insoluble hydroxysulfates (schwermannite admixed with goethite), followed by the precipitation of other relatively insoluble ferric and gypsum, and finally the occurrence of the very soluble Mg-sulfates. We are currently investigating the correlation of this evaporite deposit with the hydrochemistry of the stream water from which it evaporated through dedicated laboratory analysis of natural mineral and aqueous samples. A solubility model including the minerals identified in this work will be reported at the conference. The study of this particular acid sulfate system (with analog mineralogy to that observed in Meridiani[3]) provides constraints on the evaporation pathways

  4. Solid/liquid phase diagram of the ammonium sulfate/succinic acid/water system.

    PubMed

    Pearson, Christian S; Beyer, Keith D

    2015-05-14

    We have studied the low-temperature phase diagram and water activities of the ammonium sulfate/succinic acid/water system using differential scanning calorimetry and infrared spectroscopy of thin films. Using the results from our experiments, we have mapped the solid/liquid ternary phase diagram, determined the water activities based on the freezing point depression, and determined the ice/succinic acid phase boundary as well as the ternary eutectic composition and temperature. We also compared our results to the predictions of the extended AIM aerosol thermodynamics model (E-AIM) and found good agreement for the ice melting points in the ice primary phase field of this system; however, differences were found with respect to succinic acid solubility temperatures. We also compared the results of this study with those of previous studies that we have published on ammonium sulfate/dicarboxylic acid/water systems. PMID:25431860

  5. Kinetics of Reductive Acid Leaching of Cadmium-Bearing Zinc Ferrite Mixture Using Hydrazine Sulfate

    NASA Astrophysics Data System (ADS)

    Zhang, Chun; Zhang, Jianqiang; Min, Xiaobo; Wang, Mi; Zhou, Bosheng; Shen, Chen

    2015-09-01

    The reductive acid leaching kinetics of synthetic cadmium-bearing zinc ferrite was investigated, and the influence of reaction temperature, sulfuric acid and hydrazine sulfate were studied. The results illustrated that an increase in the reaction temperature, initial sulfuric acid and hydrazine sulfate significantly enhanced the extraction efficiencies of cadmium, zinc and iron. The leaching kinetics were controlled by a surface chemical reaction based on a shrinking core model. The empirical equation applied was found to fit well with the kinetics analysis; the leaching processes of cadmium, zinc and iron were similar and the activation energies were 79.9 kJ/mol, 77.9 kJ/mol and 79.7 kJ/mol, respectively. The apparent orders of cadmium-bearing zinc ferrite dissolution with respect to sulfuric acid concentration were 0.83, 0.83 and 0.84 for Cd, Zn and Fe, respectively.

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

    PubMed

    Fu, Yin-Chih; Wang, Yan-Hsiung; Chen, Chung-Hwan; Wang, Chih-Kuang; Wang, Gwo-Jaw; Ho, Mei-Ling

    2015-01-01

    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 of bone in the clinical setting. PMID:26664114

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

    PubMed Central

    Fu, Yin-Chih; Wang, Yan-Hsiung; Chen, Chung-Hwan; Wang, Chih-Kuang; Wang, Gwo-Jaw; Ho, Mei-Ling

    2015-01-01

    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 of bone in the clinical setting. PMID:26664114

  8. Organosulfate formation during the uptake of pinonaldehyde on acidic sulfate aerosols

    NASA Astrophysics Data System (ADS)

    Liggio, John; Li, Shao-Meng

    2006-07-01

    Organosulfates are observed in studies of pinonaldehyde reactions with acidic sulfate aerosols using aerosol mass spectrometry, during which a significant fraction of the pinonaldehyde reaction products were found to consist of organosulfate compounds that account for 6-51% of the initial SO4= mass. Resultant aerosol mass spectra were consistent with proposed sulfate ester mechanisms, which likely form stable products. The existence of organosulfates was also confirmed in studies of the reaction system in bulk solution. The formation of organosulfates suggests that conventional inorganic SO4= chemical analysis may underestimate total SO4= mass in ambient aerosols.

  9. Enhanced transformation of diphenylarsinic acid in soil under sulfate-reducing conditions.

    PubMed

    Guan, Ling; Hisatomi, Shihoko; Fujii, Kunihiko; Nonaka, Masanori; Harada, Naoki

    2012-11-30

    Diphenylarsinic acid (DPAA) is known to be the major contaminant in soils where diphenylchloroarsine and diphenylcyanoarsine were abandoned after World Wars I and II. In this study, experimental model studies were performed to elucidate key factors regulating the transformation of DPAA under anaerobic soil conditions. The elimination of DPAA in Gleysol soils (Qiqihar and Shindori soils) was more rapid than in Mollisol and Regosol soils (Heihe and Ikarashi soils, respectively) during a 5-week incubation. No clear relationship between decreasing rates of DPAA concentrations and soil Eh values was found. The Ikarashi soil showed the slowest decrease in DPAA concentrations among the four soils, but the transformation of DPAA was notably enhanced by addition of exogenous sulfate together with acetate, cellulose or rice straw. Addition of molybdate, a specific inhibitor of sulfate reduction, resulted in the stagnation of DPAA transformation, suggesting that indigenous sulfate reducers play a role in DPAA transformation under anaerobic conditions. Arsenate, phenylarsonic acid, phenylmethylarsinic acid, diphenylmethylarsine oxide and three unknown compounds were detected as metabolites of DPAA. This is the first study to reveal enhancement of DPAA transformation under sulfate-reducing conditions. PMID:23069334

  10. Stimulation of phosphatidic acid of calcium influx and cyclic GMP synthesis in neuroblastoma cells.

    PubMed

    Ohsako, S; Deguchi, T

    1981-11-10

    Phosphatidic acid added to the medium markedly elevated intracellular cyclic GMP content in cultured neuroblastoma N1E 115 cells. There was a significant elevation of cyclic GMP with 1 micrograms/ml and a maximum (70-fold) elevation with 100 micrograms/ml of phosphatidic acid. Other natural phospholipids did not increase, or increased only slightly, the cyclic GMP content in the cells. The elevation of cyclic GMP content by phosphatidic acid was absolutely dependent on extracellular calcium. Phosphatidic acid stimulated the influx of calcium into neuroblastoma cells 2- to 5-fold. The pattern of the calcium influx induced by phosphatidic acid was comparable to that of cyclic GMP elevation. The stimulation of calcium influx by phosphatidic acid was also observed in cultured heart cells, indicating that phosphatidic acid acts as a calcium ionophore or opens a specific calcium-gate in a variety of cell membranes. Treatment of neuroblastoma cells with phospholipase C increased 32Pi labeling of phosphatidic acid, stimulated the influx of calcium, and elevated the cyclic GMP content in the cells. Thus exogenous as well as endogenous phosphatidic acid stimulates the translocation of calcium across cell membranes and, as a consequence, induces the synthesis of cyclic GMP in the neuroblastoma cells.

  11. Effect of acid rain on calcium carbonate saturation in the Albemarle sound of North Carolina

    SciTech Connect

    Rudolph, K.A.; Burgess, S.K.; Willey, J.D.; Kieber, R.J.

    1996-10-01

    The effects of acidic rainwater additions on calcium carbonate solubility and alkalinity in the poorly buffered, biologically active and commercially important waters of the Albemarle Sound, NC are reported. Samples collected monthly at four sites were analyzed for salinity, pK total alkalinity, and calcium concentrations. Five percent and 10% dilutions of sulfuric acid at pH 4, mimicking acid rain additions, were added and total alkalinity and calcium concentrations again determined. The addition of acid decreased the alkalinity in the Albemarle samples by as much as 15%, although the magnitude of the impact depended both on site and season. The effects of acid additions on dissolved calcium concentrations were more variable,. and also displayed a site and season dependency. Calcium concentrations, alkalinity, and pH values were also determined during controlled laboratory experiments, where 25 mg/L Callinectes sapidus shells were added to Albemarle Sound water. All three analytes increased significantly upon acid additions relative to controls.

  12. Pulmonary effects of acid sulfate inhalation in the guinea pig

    SciTech Connect

    Silbaugh, S.A.; Mauderly, J.L.; Wolff, R.K.; Carpenter, R.L.; Brownstein, D.G.; Harkema, J.R.; Rothenberg, S.J.

    1982-07-01

    Guinea pigs were exposed by inhalation for 1 to 8 hours to sulfuric acid aerosols of various sizes and concentrations in order to provide quantitative information for standards setting. The effects of sulfuric acid aerosols were examined to determine acute mortality, changes in respiratory function and morphology, response mechanisms, differences in individual sensitivity and changes in airway response to bronchoconstrictors. An aerosol generator for another sulfur-containing pollutant, ammonium bisulfite, was developed for use in animal exposures. Also, lung lesions which simulate human emphysema were produced by intratracheal elastase instillation to investigate a potential impaired animal model for sulfur pollutant exposures. Pulmonary mechanics, lung morphology, and histamine sensitivity data all suggest that the guinea pig reacts to sulfuric acid aerosols with a nearly all-or-none airway constrictive response. Results also indicate that the concentration at which this response occurs is affected by aerosol size, exposure profile and individual animal sensitivity. No acute pulmonary function changes were noted at concentrations below 15 mg/m/sup 3/. The reason for these differences is unknown.

  13. Solid/Liquid phase diagram of the ammonium sulfate/maleic acid/water system.

    PubMed

    Beyer, Keith D; Schroeder, Jason R; Pearson, Christian S

    2011-12-01

    We have studied the low temperature phase diagram and water activities of the ammonium sulfate/maleic acid/water system using differential scanning calorimetry and infrared spectroscopy of thin films. Using the results from our experiments, we have mapped the solid/liquid ternary phase diagram, determined the water activities based on the freezing point depression, and determined the ice/maleic acid phase boundary as well as the ternary eutectic composition and temperature. We also compare our results to the predictions of the extended AIM aerosol thermodynamics model and find good agreement for the ice melting points in the ice primary phase field of this system; however significant differences were found with respect to phase boundaries, maleic acid dissolution, and ammonium sulfate dissolution. PMID:22017680

  14. Characterisation of hyaluronic acid and chondroitin/dermatan sulfate from the lumpsucker fish, C. lumpus.

    PubMed

    Panagos, Charalampos G; Thomson, Derek; Moss, Claire; Bavington, Charles D; Olafsson, Halldór G; Uhrín, Dušan

    2014-06-15

    The lumpsucker, Cyclopterus lumpus, a cottoid teleost fish found in the cold waters of the North Atlantic, and North Pacific, was identified as a possible source of GAGs. The GAGs present in the C. lumpus dorsal hump and body wall tissue were isolated and purified. Two fractions were analysed by NMR and their GAG structures determined as hyaluronic acid and CS/DS chains. The latter fraction contained GlcA (65% of the total uronic acids) and IdoA (the remaining 35%). All uronic acid residues were unsulfated, whilst 86% of the GalNAc was 4-sulfated and 14% was 6-sulfated. The presence of GlcA-GalNAc4S, IdoA-GalNAc4S and GlcA-GalNAc6S disaccharide fragments was confirmed. The isolated GAGs obtained from each tissue were biochemically characterised. The lumpsucker offers a high yield source of GAGs, which compares favourably with other sources such as shark cartilage.

  15. Comparison of sodium acid sulfate to citric acid to inhibit browning of fresh-cut potatoes.

    PubMed

    Calder, Beth L; Kash, Emily A; Davis-Dentici, Katherine; Bushway, Alfred A

    2011-04-01

    Sodium acid sulfate (SAS) dip treatments were evaluated against a distilled water control and citric acid (CA) to compare its effectiveness in reducing enzymatic browning of raw, French-fry cut potatoes. Two separate studies were conducted with dip concentrations ranging from 0%, 1%, and 3% in experiment 1 to 0%, 2%, and 2.5% in experiment 2 to determine optimal dip concentrations. Russet Burbank potatoes were peeled, sliced, and dipped for 1 min and stored at 3 °C. Color, texture, fry surface pH, and microbiological analyses were conducted on days 0, 7, and 14. The 3% SAS- and CA-treated samples had significantly (p<0.0001) lower pH levels on fry surfaces than all other treatments. Both acidulants had significantly (p≤0.05) lower aerobic plate counts compared to controls in both studies by day 7. However, SAS appeared to be the most effective at the 3% level in maintaining a light fry color up to day 14 and had the highest L-values than all other treatments. The 3% SAS-treated fry slices appeared to have the least change in textural properties over storage time, having a significantly (p=0.0002) higher force value (kg force [kgf]) than the other treatments during experiment 1, without any signs of case-hardening that appeared in the control and CA-treated samples. SAS was just as comparable to CA in reducing surface fry pH and also lowering microbial counts over storage time. According to the results, SAS may be another viable acidulant to be utilized in the fresh-cut fruit and vegetable industry.

  16. Carboxylic Acid Ionophores as Probes of the Role of Calcium in Biological Systems

    NASA Technical Reports Server (NTRS)

    Reed, P. W.

    1983-01-01

    The biological effects of calcium ionophores are described, focusing on arachidonic acid oxygenation, and the formation of a number of oxygenated metabolites of arachidonic acid. These metabolites are involved in a number of bodily functions, and their production may be regulated by calcium.

  17. Comparative effects of oral aromatic and branched-chain amino acids on urine calcium and excretion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aromatic amino acids (AAAs) bind to the calcium sensor receptor (CaR) but branched-chain amino acids (B-CAAs) do not; by binding to this receptor, AAAs have an increased potential to affect calcium homeostasis. This study was conducted to determine and compare the effects of AAAs and B-CAAs on calci...

  18. 40 CFR 721.10382 - Diphosphoric acid, calcium salt (1:1).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Diphosphoric acid, calcium salt (1:1... Specific Chemical Substances § 721.10382 Diphosphoric acid, calcium salt (1:1). (a) Chemical substance and... salt (1:1) (PMN P-10-313; CAS No. 14866-19-4) is subject to reporting under this section for...

  19. 40 CFR 721.10382 - Diphosphoric acid, calcium salt (1:1).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Diphosphoric acid, calcium salt (1:1... Specific Chemical Substances § 721.10382 Diphosphoric acid, calcium salt (1:1). (a) Chemical substance and... salt (1:1) (PMN P-10-313; CAS No. 14866-19-4) is subject to reporting under this section for...

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

    SciTech Connect

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

    2010-02-15

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

  1. Socket preservation and sinus augmentation using a medical grade calcium sulfate hemihydrate and mineralized irradiated cancellous bone allograft composite.

    PubMed

    Bagoff, Robert; Mamidwar, Sachin; Chesnoiu-Matei, Ioana; Ricci, John L; Alexander, Harold; Tovar, Nick M

    2013-06-01

    Regeneration and preservation of bone after the extraction of a tooth are necessary for the placement of a dental implant. The goal is to regenerate alveolar bone with minimal postoperative pain. Medical grade calcium sulfate hemihydrate (MGCSH) can be used alone or in combination with other bone grafts; it improves graft handling characteristics and particle containment of particle-based bone grafts. In this case series, a 1:1 ratio mix of MGCSH and mineralized irradiated cancellous bone allograft (MICBA) was mixed with saline and grafted into an extraction socket in an effort to maintain alveolar height and width for future implant placement. MGCSH can be used in combination with other bone grafts and can improve handling characteristics and graft particle containment of particle-based bone grafts. In the cases described, we found that an MGCSH:MICBA graft can potentially be an effective bone graft composite. It has the ability to act as a space maintainer and as an osteoconductive trellis for bone cells, thereby promoting bone regeneration in the extraction socket. MGCSH, a cost-effective option, successfully improved MICBA handling characteristics, prevented soft tissue ingrowth, and assisted in the regeneration of bone.

  2. A bridge to silencing: Co-assembling anionic nanoparticles of siRNA and hyaluronan sulfate via calcium ion bridges.

    PubMed

    Forti, Efrat; Kryukov, Olga; Elovic, Edan; Goldshtein, Matan; Korin, Efrat; Margolis, Gal; Felder, Shani; Ruvinov, Emil; Cohen, Smadar

    2016-06-28

    Therapeutic implementation of RNA interference (RNAi) through delivery of short interfering RNA (siRNA) is still facing several critical hurdles, which mostly can be solved through the use of an efficient delivery system. We hereby introduce anionic siRNA nanoparticles (NPs) co-assembled by the electrostatic interactions of the semi-synthetic polysaccharide hyaluronan-sulfate (HAS), with siRNA, mediated by calcium ion bridges. The NPs have an average size of 130nm and a mild (-10mV) negative surface charge. Transmission electron microscopy (TEM) using gold-labeled components and X-ray photoelectron spectroscopy (XPS) demonstrated the spatial organization of siRNA molecules in the particle core, surrounded by a layer of HAS. The anionic NPs efficiently encapsulated siRNA, were stable in physiological-relevant environments and were cytocompatible, not affecting cell viability or homeostasis. Efficient cellular uptake of the anionic siRNA NPs, associated with potent gene silencing (>80%), was observed across multiple cell types, including murine primary peritoneal macrophages and human hepatocellular carcinoma cells. In a clinically-relevant model of acute inflammatory response in IL-6-stimulated human hepatocytes, STAT3 silencing induced by HAS-Ca(2+)-siRNA NPs resulted in marked decrease in the total and activated STAT3 protein levels, as well as in the expression levels of downstream acute phase response genes. Collectively, anionic NPs prove to be an efficient and cytocompatible delivery system for siRNA. PMID:27117458

  3. Immobilizing Water into Crystal Lattice of Calcium Sulfate for its Separation from Water-in-Oil Emulsion.

    PubMed

    Jiang, Guangming; Li, Junxi; Nie, Yunliang; Zhang, Sen; Dong, Fan; Guan, Baohong; Lv, Xiaoshu

    2016-07-19

    This work report a facile approach to efficiently separate surfactant-stabilized water (droplet diameter of around 2.0 μm) from water-in-oil emulsion via converting liquid water into solid crystal water followed by removal with centrifugation. The liquid-solid conversion is achieved through the solid-to-solid phase transition of calcium sulfate hemihydrate (CaSO4. 0.5H2O, HH) to dihydrate (CaSO4·2H2O, DH), which could immobilize the water into crystal lattice of DH. For emulsion of 10 mg mL(-1) water, the immobilization-separation process using polycrystalline HH nanoellipsoids could remove 95.87 wt % water at room temperature. The separation efficiency can be further improved to 99.85 wt % by optimizing the HH dosage, temperature, HH size and crystalline structure. Property examination of the recycled oil confirms that our method has neglectable side-effect on oil quality. The byproduct DH was recycled to alpha-HH (a valuable cemetitious material widely used in construction and binding field), which minimizes the risk of secondary pollution and promotes the practicality of our method. With the high separation efficiency, the "green" feature and the recyclability of DH byproduct, the HH-based immobilization-separation approach is highly promising in purifying oil with undesired water contamination. PMID:27322639

  4. Mineral species control of aluminum solubility in sulfate-rich acidic waters

    NASA Astrophysics Data System (ADS)

    Jones, Adele M.; Collins, Richard N.; Waite, T. David

    2011-02-01

    The identification of the mineral species controlling the solubility of Al in acidic waters rich in sulfate has presented researchers with several challenges. One of the particular challenges is that the mineral species may be amorphous by X-ray diffraction. The difficulty in discerning between adsorbed or structural sulfate is a further complication. Numerous studies have employed theoretical calculations to determine the Al mineral species forming in acid sulfate soil environments. The vast majority of these studies indicate the formation of a mineral species matching the stoichiometry of jurbanite, Al(OH)SO 4·5H 2O. Much debate, however, exists as to the reality of jurbanite forming in natural environments, particularly in view of its apparent rare occurrence. In this work the use of Al, S and O K-edge XANES spectroscopy, in combination with elemental composition analyses of groundwater precipitates and a theoretical analysis of soluble Al concentrations ranging from pH 3.5 to 7, were employed to determine the mineral species controlling the solubility of Al draining from acid sulfate soils into Blacks Drain in north-eastern New South Wales, Australia. The results indicate that a mixture of amorphous Al hydroxide (Al(OH) 3) and basaluminite (Al 4(SO 4)(OH) 10·5H 2O) was forming. The use of XANES spectroscopy is particularly useful as it provides insight into the nature of the bond between sulfate and Al, and confirms the presence of basaluminite. This counters the possibility that an Al hydroxide species, with appreciable amounts of adsorbed sulfate, is forming within these groundwaters. Below approximately pH 4.5, prior to precipitation of this amorphous Al(OH) 3/basaluminite mixture, our studies indicate that the Al 3+ activity of these acidic sulfate-rich waters is limited by the availability of dissolved Al from exchangeable and amorphous/poorly crystalline mineral species within adjacent soils. Further evidence suggests the Al 3+ activity below pH 4.5 is

  5. Sulfation of metal-organic framework: Opportunities for acid catalysis and proton conductivity

    SciTech Connect

    Goesten, M.G.; Stavitski, E.; Juan-Alcaniz, J.; Ramos-Fernandez, E.V.; Sai Sankar Gupta, K.B.; van Bekkum, H.; Gascon, J. and Kapteijn, F.

    2011-05-24

    A new post-functionalization method for metal-organic frameworks (MOFs) has been developed to introduce acidity for catalysis. Upon treatment with a mixture of triflic anhydride and sulfuric acid, chemically stable MOF structures MIL-101(Cr) and MIL-53(Al) can be sulfated, resulting in a Broensted sulfoxy acid group attached to up to 50% of the aromatic terephthalate linkers of the structure. The sulfated samples have been extensively characterized by solid-state NMR, XANES, and FTIR spectroscopy. The functionalized acidic frameworks show catalytic activity similar to that of acidic polymers like Nafion{reg_sign} display in the esterification of n-butanol with acetic acid (TOF {approx} 1 min{sup -1} {at} 343 K). Water adsorbs strongly up to 4 molecules per sulfoxy acid group, and an additional 2 molecules are taken up at lower temperatures in the 1-D pore channels of S-MIL-53(Al). The high water content and Broensted acidity provide the structure S-MIL-53(Al) a high proton conductivity up to moderate temperatures.

  6. Volatile fatty acids as substrates for iron and sulfate reduction in Arctic marine sediments, Svalbard

    NASA Astrophysics Data System (ADS)

    Finke, N.; Vandieken, V.; Jorgensen, B. B.

    2006-12-01

    Anaerobic degradation of complex organic material in aquatic systems is a multi-step process. The metabolic products of fermentative bacteria serve as electron donors for the terminal oxidizing bacteria. In marine sediments, iron reduction and sulfate reduction are generally the most important terminal oxidation processes in the upper anoxic zone [1]. Microorganisms that reduce iron and sulfate may use a broad range of electron donors, yet the list of potential substrates provides little information about the substrates used in situ by these organisms. Investigations on the electron donors for sulfate reducers in marine sediments have shown that volatile fatty acids (VFA), and in particular acetate, together with hydrogen are the major substrates (e.g. [2-4]). Similar investigations for iron reduction or simultaneous iron and sulfate reduction are lacking for marine sediments. Furthermore, most of these studies were made in temperate sediments and little is known about the substrates for sulfate reducers in permanently cold sediments, which account for >90% of the ocean floor [5]. We investigated the relative contributions of iron reduction and sulfate reduction to the terminal oxidation of organic carbon and the importance of acetate, lactate, propionate, and isobutyrate as electron donors for iron and sulfate reduction in permanently cold, Arctic sediments from Svalbard. In the surface layer (0-2 cm) sulfate reduction accounted for 2/3 of the organic carbon oxidation (determined as DIC production), the remaining 1/3 were attributed to iron reduction. In the 5-9 cm layer sulfate reduction was the sole important terminal oxidation step. The contribution of acetate to terminal oxidation was determined by radiotracer incubation as well as from the accumulation after the inhibition of sulfate reduction by selenate. The rates determined with the two methods varied by less than 20%. Acetate turnover, determined with the tracer incubations, accounted for 10 and 40% of

  7. Sulfate-reducing bacteria mediate thionation of diphenylarsinic acid under anaerobic conditions.

    PubMed

    Guan, Ling; Shiiya, Ayaka; Hisatomi, Shihoko; Fujii, Kunihiko; Nonaka, Masanori; Harada, Naoki

    2015-02-01

    Diphenylarsinic acid (DPAA) is often found as a toxic intermediate metabolite of diphenylchloroarsine or diphenylcyanoarsine that were produced as chemical warfare agents and were buried in soil after the World Wars. In our previous study Guan et al. (J Hazard Mater 241-242:355-362, 2012), after application of sulfate and carbon sources, anaerobic transformation of DPAA in soil was enhanced with the production of diphenylthioarsinic acid (DPTAA) as a main metabolite. This study aimed to isolate and characterize anaerobic soil microorganisms responsible for the metabolism of DPAA. First, we obtained four microbial consortia capable of transforming DPAA to DPTAA at a high transformation rate of more than 80% after 4 weeks of incubation. Sequencing for the bacterial 16S rRNA gene clone libraries constructed from the consortia revealed that all the positive consortia contained Desulfotomaculum acetoxidans species. In contrast, the absence of dissimilatory sulfite reductase gene (dsrAB) which is unique to sulfate-reducing bacteria was confirmed in the negative consortia showing no DPAA reduction. Finally, strain DEA14 showing transformation of DPAA to DPTAA was isolated from one of the positive consortia. The isolate was assigned to D. acetoxidans based on the partial 16S rDNA sequence analysis. Thionation of DPAA was also carried out in a pure culture of a known sulfate-reducing bacterial strain, Desulfovibrio aerotolerans JCM 12613(T). These facts indicate that sulfate-reducing bacteria are microorganisms responsible for the transformation of DPAA to DPTAA under anaerobic conditions. PMID:25228086

  8. Sulfate-reducing bacteria mediate thionation of diphenylarsinic acid under anaerobic conditions.

    PubMed

    Guan, Ling; Shiiya, Ayaka; Hisatomi, Shihoko; Fujii, Kunihiko; Nonaka, Masanori; Harada, Naoki

    2015-02-01

    Diphenylarsinic acid (DPAA) is often found as a toxic intermediate metabolite of diphenylchloroarsine or diphenylcyanoarsine that were produced as chemical warfare agents and were buried in soil after the World Wars. In our previous study Guan et al. (J Hazard Mater 241-242:355-362, 2012), after application of sulfate and carbon sources, anaerobic transformation of DPAA in soil was enhanced with the production of diphenylthioarsinic acid (DPTAA) as a main metabolite. This study aimed to isolate and characterize anaerobic soil microorganisms responsible for the metabolism of DPAA. First, we obtained four microbial consortia capable of transforming DPAA to DPTAA at a high transformation rate of more than 80% after 4 weeks of incubation. Sequencing for the bacterial 16S rRNA gene clone libraries constructed from the consortia revealed that all the positive consortia contained Desulfotomaculum acetoxidans species. In contrast, the absence of dissimilatory sulfite reductase gene (dsrAB) which is unique to sulfate-reducing bacteria was confirmed in the negative consortia showing no DPAA reduction. Finally, strain DEA14 showing transformation of DPAA to DPTAA was isolated from one of the positive consortia. The isolate was assigned to D. acetoxidans based on the partial 16S rDNA sequence analysis. Thionation of DPAA was also carried out in a pure culture of a known sulfate-reducing bacterial strain, Desulfovibrio aerotolerans JCM 12613(T). These facts indicate that sulfate-reducing bacteria are microorganisms responsible for the transformation of DPAA to DPTAA under anaerobic conditions.

  9. Fluctuations of sulfate, S-bearing amino acids and magnesium in a giant clam shell

    NASA Astrophysics Data System (ADS)

    Yoshimura, T.; Tamenori, Y.; Kawahata, H.; Suzuki, A.

    2014-01-01

    We used micro-X-ray fluorescence combined with X-ray photoabsorption spectroscopy to investigate speciation-specific sulfur profiles in the inner shell layer of a giant clam (Hippopus hippopus). The sulfate, S-bearing amino acids, and total sulfur profiles indicated that inorganic sulfate was the dominant component in the shell of this bivalve. Sulfur profiles in the inner shell layer showed clear annual fluctuations that varied by more than one order of magnitude, from < 50 to 1420 ppm, and sulfate and total sulfur maxima became higher with age, whereas no ontogenetic trend was noticeable in the profile of S-bearing amino acids. A changes in the carbonate ion concentration in the calcifying fluid would suggest that an ontogenetic increase in the relative activity of sulfate ions to carbonate ions in the calcifying fluid affects sulfate concentrations in the shells. These results suggest that trace sulfur profiles in the shell of the giant clam may reflect both cyclic shell growth related to environmental factors such as insolation and temperature and ontogenetic changes of the calcifying fluid chemistry mediated by physiological processes. The observed S profile implies a clear change in calcifying fluid chemistry towards less alkaline condition with age. Magnesium fluctuations suggested that Mg was incorporated into the shells at high growth rates during warm seasons. The spectrum of Mg K-edge XANES and comparison of Mg and S-bearing amino acids profiles indicated that a pronounced effect of the organic fraction or disordered phases were observed in aragonitic shell of H. hippopus rather than regulated substitution into the aragonite crystal lattice.

  10. Fluctuations of sulfate, S-bearing amino acids and magnesium in a giant clam shell

    NASA Astrophysics Data System (ADS)

    Yoshimura, T.; Tamenori, Y.; Kawahata, H.; Suzuki, A.

    2014-07-01

    We used micro-X-ray fluorescence combined with X-ray photoabsorption spectroscopy to investigate speciation-specific sulfur profiles in the inner shell layer of a giant clam (Hippopus hippopus). The sulfate, S-bearing amino acids, and total sulfur profiles indicated that inorganic sulfate was the dominant component in the shell of this bivalve. Sulfur profiles in the inner shell layer showed clear annual fluctuations that varied by more than one order of magnitude, from < 50 to 1420 ppm, and sulfate and total sulfur maxima became higher with age, whereas no ontogenetic trend was noticeable in the profile of S-bearing amino acids. A change in the carbonate ion concentration in the calcifying fluid would suggest that an ontogenetic increase in the relative activity of sulfate ions to carbonate ions in the calcifying fluid affects sulfate concentrations in the shells. These results suggest that trace sulfur profiles in the shell of the giant clam may reflect both cyclic shell growth related to environmental factors such as insolation and temperature and ontogenetic changes of the calcifying fluid chemistry mediated by physiological processes. The observed S profile implies a clear change in calcifying fluid chemistry towards less alkaline condition with age. Magnesium fluctuations suggested that Mg was incorporated into the shells at high growth rates during warm seasons. The spectrum of Mg K-edge X-ray absorption near edge structure (XANES) and comparison of Mg and S-bearing amino acids profiles indicated that a pronounced effect of the organic fraction or disordered phases were observed in aragonitic shell of H. hippopus rather than regulated substitution into the aragonite crystal lattice.

  11. Nucleation of calcium carbonate in presence of citric acid, DTPA, EDTA and pyromellitic acid.

    PubMed

    Westin, K-J; Rasmuson, A C

    2005-02-15

    The influence of four calcium complexing additives, i.e., citric acid (CIT), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA) and pyromellitic acid (PMA), and their concentration on the induction time of calcium carbonate nucleation has been studied. The experiments were performed by rapidly mixing a sodium carbonate solution and a calcium chloride solution of various concentrations. The induction time was obtained by recording the white light absorption of the solution. Chemical speciation was used to estimate the initial thermodynamic driving force of each experiment. The induction time was found to increase with additive concentration. The effect varies from one additive to another. CIT causes the greatest increase in induction time and PMA the least. Using classical nucleation theory the experimental data were evaluated in terms of the interfacial energy. In pure water a value of 37.8 mJ m(-2) was obtained, showing good agreement with other works. CIT, DTPA and EDTA caused a notable increase of the interfacial energy at a concentration of 0.5 mmol l(-1). PMA does not appear to have any effect at all on the interfacial energy. Different mechanisms for the influence of the additives on the measured induction time and on the estimated interfacial energy are discussed. PMID:15589542

  12. Mineralogy and Organic Geochemistry of Acid Sulfate Environments from Valles Caldera, New Mexico: Habitability, Weathering and Biosignatures

    NASA Astrophysics Data System (ADS)

    Vogel, M. B.; Des Marais, D. J.; Jahnke, L. L.; Kubo, M.

    2009-12-01

    We report on the mineralogy, organic preservation potential and habitability of sulfate deposits in acid sulfate volcanic settings at Valles Caldera, New Mexico. Fumaroles and acidic springs are potential analogs for aqueous environments on Mars and may offer insights into habitability of sulfate deposits such as those at Meridiani Planum. Sulfates recently detected on Mars are posited to have formed from fluids derived from basaltic weathering and igneous volatile input, ultimately precipitating from acidic brines subjected to desiccation and freeze-thaw cycles (McClennan and Grotzinger, 2008). Key issues concerning martian sulfate deposits are their relationship to aqueous clay deposits, and whether or not specific sulfates deposits represent former habitable environments (see Soderblum and Bell, 2008; Tosca et al., 2008). Modern terrestrial volcanic fumaroles and hot springs precipitate various Ca-, Mg- and Fe- sulfates along with clays, and can help clarify whether certain acid sulfate mineral assemblages reflect habitable environments. Valles caldera is a resurgent caldera last active in the Pleistocene (1.4 - 1.0 Ma) that hosts several active fumaroles and over 40 geothermal exploration wells (see Goff, 2009). Fumaroles and associated mudpots and springs at Valles range from pH < 1 to 3, and affect argillic alteration upon rhylolitic tuffs and sedimentary deposits (Charles et al., 1986). We identified assemblages containing gypsum, quartz, Al-sulfates, elemental sulfur, clays and other minerals using XRD and SEM-EDS. Our previous research has shown that sulfates from different marine depositional environments display textural and morphological traits that are indicative of biological influence, or specific conditions in the depositional environments (Vogel et al., 2009). Gypsum crystals that develop in the presence of microbial biofilms in marine environments may have distorted crystal morphologies, biofilm - associated dissolution features, and accessory

  13. Possibility of one-stage surgery to reconstruct bone defects using the modified Masquelet technique with degradable calcium sulfate as a cement spacer: A case report and hypothesis

    PubMed Central

    JIANG, NAN; QIN, CHENG-HE; MA, YUN-FEI; WANG, LEI; YU, BIN

    2016-01-01

    In addition to autologous bone graft, vascularized fibular autograft and Ilizarov bone transfer, the Masquelet technique is another effective method to reconstruct bone defects. This technique was initially proposed in 1986 and consists of two stages. At the first stage, radical debridement is required and subsequently, a polymethylmethacrylate (PMMA) cement spacer is implanted at the site of the bone defects. At the second stage, when the PMMA-induced membrane is formed 6–8 weeks later, the cement spacer is carefully removed in order to not disturb the induced membrane and the bone graft is performed to fill the bone defects. Although this technique has resulted in satisfactory outcomes in the reconstruction of bone defects, the PMMA spacer used to induce membrane is not degradable and requires surgical removal. In recent years, calcium sulfate has been used as a localized antibiotic delivery vehicle and bone substitute due to its superiorities over PMMA, particularly its completely degradable nature. The present study identified that calcium sulfate can also induce the formation of a membrane. In addition, we hypothesized that the degradability of calcium sulfate may allow one-stage reconstruction of bone defects. The current study presents a clinical case report and review of the literature. PMID:26998279

  14. Improved process for the production of cellulose sulfate using sulfuric acid/ethanol solution.

    PubMed

    Chen, Guo; Zhang, Bin; Zhao, Jun; Chen, Hongwen

    2013-06-01

    An improved process for production of cellulose sulfate (CS) was developed by using sulfuric acid/ethanol solution as sulfonating agent and Na2SO4 as water absorbent. The FTIR, SEM and TG analysis were used to characterize the CS prepared. The total degree of substitution and viscosity of the product solution (2%, w/v) were ranging from 0.28 to 0.77 and from 115 to 907 mPa s, respectively, by changing the process parameters such as the amount of Na2SO4, the reaction time, the temperature, the sulfuric acid/alcohol ratio and liquid/solid ratio. The results indicated that the product with DS (0.28-0.77) and η2% (115-907) mPa s could be produced by using this improved process and more cellulose sulfate could be produced when cellulose was sulfonated for 3-4 h at -2 °C in sulfuric acid/ethanol (1.4-1.6) solution with addition of 0.8 g Na2SO4. The (13)C NMR indicated that the sulfate group of CS produced using sulfuric acid/ethanol solution was at C6 position.

  15. Hexuronic acid stereochemistry determination in chondroitin sulfate glycosaminoglycan oligosaccharides by electron detachment dissociation.

    PubMed

    Leach, Franklin E; Ly, Mellisa; Laremore, Tatiana N; Wolff, Jeremy J; Perlow, Jacob; Linhardt, Robert J; Amster, I Jonathan

    2012-09-01

    Electron detachment dissociation (EDD) has previously provided stereo-specific product ions that allow for the assignment of the acidic C-5stereochemistry in heparan sulfate glycosaminoglycans (GAGs), but application of the same methodology to an epimer pair in the chondroitin sulfate glycoform class does not provide the same result. A series of experiments have been conducted in which glycosaminoglycan precursor ions are independently activated by electron detachment dissociation (EDD), electron induced dissociation (EID), and negative electron transfer dissociation (NETD) to assign the stereochemistry in chondroitin sulfate (CS) epimers and investigate the mechanisms for product ion formation during EDD in CS glycoforms. This approach allows for the assignment of electronic excitation products formed by EID and detachment products to radical pathways in NETD, both of which occur simultaneously during EDD. The uronic acid stereochemistry in electron detachment spectra produces intensity differences when assigned glycosidic and cross-ring cleavages are compared. The variations in the intensities of the doubly deprotonated (0,2)X(3) and Y(3) ions have been shown to be indicative of CS-A/DS composition during the CID of binary mixtures. These ions can provide insight into the uronic acid composition of binary mixtures in EDD, but the relative abundances, although reproducible, are low compared with those in a CID spectrum acquired on an ion trap. The application of principal component analysis (PCA) presents a multivariate approach to determining the uronic acid stereochemistry spectra of these GAGs by taking advantage of the reproducible peak distributions produced by electron detachment.

  16. Hexuronic Acid Stereochemistry Determination in Chondroitin Sulfate Glycosaminoglycan Oligosaccharides by Electron Detachment Dissociation

    NASA Astrophysics Data System (ADS)

    Leach, Franklin E.; Ly, Mellisa; Laremore, Tatiana N.; Wolff, Jeremy J.; Perlow, Jacob; Linhardt, Robert J.; Amster, I. Jonathan

    2012-09-01

    Electron detachment dissociation (EDD) has previously provided stereo-specific product ions that allow for the assignment of the acidic C-5stereochemistry in heparan sulfate glycosaminoglycans (GAGs), but application of the same methodology to an epimer pair in the chondroitin sulfate glycoform class does not provide the same result. A series of experiments have been conducted in which glycosaminoglycan precursor ions are independently activated by electron detachment dissociation (EDD), electron induced dissociation (EID), and negative electron transfer dissociation (NETD) to assign the stereochemistry in chondroitin sulfate (CS) epimers and investigate the mechanisms for product ion formation during EDD in CS glycoforms. This approach allows for the assignment of electronic excitation products formed by EID and detachment products to radical pathways in NETD, both of which occur simultaneously during EDD. The uronic acid stereochemistry in electron detachment spectra produces intensity differences when assigned glycosidic and cross-ring cleavages are compared. The variations in the intensities of the doubly deprotonated 0,2X3 and Y3 ions have been shown to be indicative of CS-A/DS composition during the CID of binary mixtures. These ions can provide insight into the uronic acid composition of binary mixtures in EDD, but the relative abundances, although reproducible, are low compared with those in a CID spectrum acquired on an ion trap. The application of principal component analysis (PCA) presents a multivariate approach to determining the uronic acid stereochemistry spectra of these GAGs by taking advantage of the reproducible peak distributions produced by electron detachment.

  17. Water uptake of internally mixed ammonium sulfate and dicarboxylic acid particles probed by infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Miñambres, Lorena; Méndez, Estíbaliz; Sánchez, María N.; Castaño, Fernando; Basterretxea, Francisco J.

    2013-05-01

    Tropospheric aerosols are usually mixtures of inorganic and organic compounds in variable proportions, and the relative amount of organic fraction can influence the hygroscopic properties of the particles. Infrared spectra of submicrometer internally mixed dry particles of ammonium sulfate (AS) with various dicarboxylic acids (oxalic, malonic, maleic, glutaric and pimelic) have been measured in an aerosol flow tube at several solute mass ratios. The spectra show a notable broadening in the bandwidth of sulfate ion ν3 vibrational band near 1115 cm-1 with respect to pure AS. We attribute these perturbations, that are biggest at AS/organic acid mass ratio near unity, to intermolecular interactions between inorganic ions and organic acid molecules in the internally mixed solids. The water uptake behavior of internally mixed particles has been measured by recording the infrared integrated absorbance of liquid water as a function of relative humidity (RH). The amount of water present in the particles prior to deliquescence correlates partially with the water solubilities of the dicarboxylic acids, and also with the relative magnitudes of intermolecular interactions in the internally mixed dry solids. Phase change of ammonium sulfate in the internally mixed particles with RH has been spectrally monitored, and it is shown that water uptaken before full deliquescence produces structural changes in the particles that are revealed by their vibrational spectra.

  18. Biological treatment of heavy metals in acid mine drainage using sulfate reducing bioreactors.

    PubMed

    Sierra-Alvarez, R; Karri, S; Freeman, S; Field, J A

    2006-01-01

    The uncontrolled release of acid mine drainage (AMD) from abandoned mines and tailing piles threatens water resources in many sites worldwide. AMD introduces elevated concentrations of sulfate ions and dissolved heavy metals as well as high acidity levels to groundwater and receiving surface water. Anaerobic biological processes relying on the activity of sulfate reducing bacteria are being considered for the treatment of AMD and other heavy metal containing effluents. Biogenic sulfides form insoluble complexes with heavy metals resulting in their precipitation. The objective of this study was to investigate the remediation of AMD in sulfate reducing bioreactors inoculated with anaerobic granular sludge and fed with an influent containing ethanol. Biological treatment of an acidic (pH 4.0) synthetic AMD containing high concentrations of heavy metals (100 mg Cu(2+)l(-1); 10 mg Ni(2+)l(-1), 10 mg Zn(2+)l(-1)) increased the effluent pH level to 7.0-7.2 and resulted in metal removal efficiencies exceeding 99.2%. The highest metal precipitation rates attained for Cu, Ni and Zn averaged 92.5, 14.6 and 15.8 mg metal l(-1) of reactor d(-1). The results of this work demonstrate that an ethanol-fed sulfidogenic reactor was highly effective to remove heavy metal contamination and neutralized the acidity of the synthetic wastewater.

  19. Antimicrobial Effect of Calcium Chloride Alone and Combined with Lactic Acid Injected into Chicken Breast Meat.

    PubMed

    Alahakoon, Amali U; Jayasena, Dinesh D; Jung, Samooel; Kim, Hyun Joo; Kim, Sun Hyo; Jo, Cheorun

    2014-01-01

    Chicken breast meat was injected with calcium chloride alone and in combination with lactic acid (0.01% and 0.002%, respectively). The inhibitory effects of the treatments on microbial growth were determined in the injected chicken breast meat stored at 4°C under aerobic packaging condition for 0, 3, and 7 d. Calcium chloride combined with 0.002% and 0.01% lactic acid reduced microbial counts by 0.14 and 1.08 Log CFU/g, respectively, however, calcium chloride alone was unable to inhibit microbial growth. Calcium chloride combined with 0.01% lactic acid was the most effective antimicrobial treatment and resulted in the highest initial redness value. Calcium chloride alone and combined with lactic acid suppressed changes in pH and the Hunter color values during storage. However, injection of calcium chloride and lactic acid had adverse effects on lipid oxidation and sensory characteristics. The higher TBARS values were observed in samples treated with calcium chloride and lactic acid when compared to control over the storage period. Addition of calcium chloride and lactic acid resulted in lower sensory scores for parameters tested, except odor and color, compared to control samples. Therefore, the formulation should be improved in order to overcome such defects prior to industrial application.

  20. Antimicrobial Effect of Calcium Chloride Alone and Combined with Lactic Acid Injected into Chicken Breast Meat

    PubMed Central

    Alahakoon, Amali U.; Jayasena, Dinesh D.; Jung, Samooel; Kim, Sun Hyo

    2014-01-01

    Chicken breast meat was injected with calcium chloride alone and in combination with lactic acid (0.01% and 0.002%, respectively). The inhibitory effects of the treatments on microbial growth were determined in the injected chicken breast meat stored at 4°C under aerobic packaging condition for 0, 3, and 7 d. Calcium chloride combined with 0.002% and 0.01% lactic acid reduced microbial counts by 0.14 and 1.08 Log CFU/g, respectively, however, calcium chloride alone was unable to inhibit microbial growth. Calcium chloride combined with 0.01% lactic acid was the most effective antimicrobial treatment and resulted in the highest initial redness value. Calcium chloride alone and combined with lactic acid suppressed changes in pH and the Hunter color values during storage. However, injection of calcium chloride and lactic acid had adverse effects on lipid oxidation and sensory characteristics. The higher TBARS values were observed in samples treated with calcium chloride and lactic acid when compared to control over the storage period. Addition of calcium chloride and lactic acid resulted in lower sensory scores for parameters tested, except odor and color, compared to control samples. Therefore, the formulation should be improved in order to overcome such defects prior to industrial application. PMID:26760942

  1. Evaluation of sulfated polysaccharides from the brown seaweed Dictyopteris justii as antioxidant agents and as inhibitors of the formation of calcium oxalate crystals.

    PubMed

    Melo, Karoline Rachel Teodosio; Camara, Rafael Barros Gomes; Queiroz, Moacir Fernandes; Vidal, Arthur Anthunes Jacome; Lima, Camila Renata Machado; Melo-Silveira, Raniere Fagundes; Almeida-Lima, Jailma; Rocha, Hugo Alexandre Oliveira

    2013-01-01

    Oxalate crystals and other types of crystals are the cause of urolithiasis, and these are related to oxidative stress. The search for new compounds with antioxidant qualities and inhibitors of these crystal formations is therefore necessary. In this study, we extracted four sulfated polysaccharides, a fucoglucoxyloglucuronan (DJ-0.3v), a heterofucan (DJ-0.4v), and two glucans (DJ-0.5v and DJ-1.2v), from the marine alga Dictyopteris justii. The presence of sulfated polysaccharides was confirmed by chemical analysis and FT-IR. All the sulfated polysaccharides presented antioxidant activity under different conditions in some of the in vitro tests and inhibited the formation of calcium oxalate crystals. Fucan DJ-0.4v was the polysaccharide that showed the best antioxidant activity and was one of the best inhibitors of the crystallization of calcium oxalate. Glucan DJ-0.5v was the second most potent inhibitor of the formation of oxalate crystals, as it stabilized dehydrated oxalate crystals (less aggressive form), preventing them from transforming into monohydrate crystals (more aggressive form). The obtained data lead us to propose that these sulfated polysaccharides are promising agents for use in the treatment of urolithiasis. PMID:24287990

  2. Geology and geochemistry of Summitville, Colorado: an epithermal acid sulfate deposit in a volcanic dome

    USGS Publications Warehouse

    Gray, J.E.; Coolbaugh, M.F.

    1994-01-01

    Geologic studies during recent open-pit mining at Summitville, Colorado, have provided new information on an epithermal acid sulfate Au-Ag-Cu deposit formed in a volcanic dome. Geologic mapping, geochemical studies of whole-rock samples from blast holes, and geologic and geochemical traverse studies refine the details of the evolution of the Summitville deposit. Six distinct events followed emplacement of the quartz latite volcanic dome and define the development of the Summitville deposit: 1) an early stage of acid sulfate alteration, 2) subsequent Cu sulfide and gold mineralization, 3) widespread hydrothermal brecciation, 4) volumetrically minor, base metal sulfide-bearing barite veining, 5) volumetrically minor, kaolinite matrix brecciation, and finally, 6) supergene oxidation. -from Authors

  3. Remediation of acid mine drainage within strip mine spoil by sulfate reduction using waste organic matter

    SciTech Connect

    Stalker, J.; Rose, A.W.; Michaud, L.H.

    1996-12-31

    Many treatment options for AMD, like wetlands and anoxic limestone drains, are limited by acidity, metal loadings, flow rate or areal requirements so as to be inapplicable at many sites. In-situ bacterial sulfate reduction is proposed as a solution for certain settings. Requirements for successful in-situ bacterial sulfate reduction include dissolved sulfate, an organic substrate, permanent anaerobic conditions, a mixed culture of bacteria, appropriate nutrients, and a sufficient AMD contact time. These requirements can be provided within mine spoil by injection of waste organic matter into an extensive zone of saturated spoil. Laboratory experiments on cheese whey, lactate, non-degraded sawdust, partially degraded sawdust, pulped newspaper and mushroom compost have all yielded sulfate reduction, increased alkalinity and iron sulfide precipitate in AMD with pH < 4.0. The addition of a small amount of dolomite to the organic matter creates alkaline microenvironments that facilitate the initiation of sulfate reduction. The rates of sulfate reduction using cellulose materials are slow but the rate for milk products is much more rapid. A field test utilizing partially degraded sawdust is underway. A total of 11.3 tons of sawdust mixed with 5% dolomite, 5% sewage sludge and a mixed bacterial culture was successfully injected into 4 drill holes in mine spoil as 13% w/v suspension, The spoil had enough coarse porosity for injection into the saturated subsurface at about 300 L/min, Data on in-situ SO{sub 4} reduction rates and water quality are being collected in preparation for a full remediation program at the site, which has an extensive zone of saturated spoil 10-20 m thick.

  4. Acid-Sulfate-Weathering Activity in Shergottite Sites on Mars Recorded in Grim Glasses

    NASA Technical Reports Server (NTRS)

    Rao, M. N.; Nyquist, L. E.; Ross, K.; Sutton, S. R.; Schwandt, C. S.

    2011-01-01

    Based on mass spectrometric studies of sulfur species in Shergotty and EET79001, [1] and [2] showed that sulfates and sulfides occur in different proportions in shergottites. Sulfur speciation studies in gas-rich impact-melt (GRIM) glasses in EET79001 by the XANES method [3] showed that S K-XANES spectra in GRIM glasses from Lith A indicate that S is associated with Ca and Al presumably as sulfides/sulfates whereas the XANES spectra of amorphous sulfide globules in GRIM glasses from Lith B indicate that S is associated with Fe as FeS. In these amorphous iron sulfide globules, [4] found no Ni using FE-SEM and suggested that the globules resulting from immiscible sulfide melt may not be related to the igneous iron sulfides having approximately 1-3% Ni. Furthermore, in the amorphous iron sulfides from 507 GRIM glass, [5] determined delta(sup 34)S values ranging from +3.5%o to -3.1%o using Nano-SIMS. These values plot between the delta(sup 34)S value of +5.25%o determined in the sulfate fraction in Shergotty [6] at one extreme and the value of -1.7%o obtained for igneous sulfides in EET79001 and Shergotty [7] at the other. These results suggest that the amorphous Fe-S globules likely originated by shock reduction of secondary iron sulfate phases occurring in the regolith precursor materials during impact [7]. Sulfates in the regolith materials near the basaltic shergottite sites on Mars owe their origin to surficial acid-sulfate interactions. We examine the nature of these reactions by studying the composition of the end products in altered regolith materials. For the parent material composition, we use that of the host shergottite material in which the impact glasses are situated.

  5. Unsaturated fatty acids induce calcium influx into keratinocytes and cause abnormal differentiation of epidermis.

    PubMed

    Katsuta, Yuji; Iida, Toshii; Inomata, Shinji; Denda, Mitsuhiro

    2005-05-01

    Abnormal follicular keratinization is involved in comedogenesis in acne vulgaris. We recently demonstrated that calcium influx into epidermal keratinocytes is associated with impaired skin barrier function and epidermal proliferation. Based on these results, we hypothesized that sebum components affect calcium dynamics in the keratinocyte and consequently induce abnormal keratinization. To test this idea, we first observed the effects of topical application of sebum components, triglycerides (triolein), saturated fatty acids (palmitic acid and stearic acid), and unsaturated fatty acids (oleic acid and palmitoleic acid) on hairless mouse skin. Neither triglyceride nor saturated fatty acids affected the skin surface morphology or epidermal proliferation. On the other hand, application of unsaturated fatty acids, oleic acid, and palmitoleic acid induced scaly skin, abnormal keratinization, and epidermal hyperplasia. Application of triglycerides and saturated fatty acids on cultured human keratinocytes did not affect the intracellular calcium concentration ([Ca(2+)](i)), whereas unsaturated fatty acids increased the [Ca(2+)](i) of the keratinocytes. Moreover, application of oleic acid on hairless mouse skin induced an abnormal calcium distribution in the epidermis. These results suggest that unsaturated fatty acids in sebum alter the calcium dynamics in epidermal keratinocytes and induce abnormal follicular keratinization.

  6. A Small Molecule Inhibits Virion Attachment to Heparan Sulfate- or Sialic Acid-Containing Glycans

    PubMed Central

    Colpitts, Che C.

    2014-01-01

    ABSTRACT Primary attachment to cellular glycans is a critical entry step for most human viruses. Some viruses, such as herpes simplex virus type 1 (HSV-1) and hepatitis C virus (HCV), bind to heparan sulfate, whereas others, such as influenza A virus (IAV), bind to sialic acid. Receptor mimetics that interfere with these interactions are active against viruses that bind to either heparan sulfate or to sialic acid. However, no molecule that inhibits the attachment of viruses in both groups has yet been identified. Epigallocatechin gallate (EGCG), a green tea catechin, is active against many unrelated viruses, including several that bind to heparan sulfate or to sialic acid. We sought to identify the basis for the broad-spectrum activity of EGCG. Here, we show that EGCG inhibits the infectivity of a diverse group of enveloped and nonenveloped human viruses. EGCG acts directly on the virions, without affecting the fluidity or integrity of the virion envelopes. Instead, EGCG interacts with virion surface proteins to inhibit the attachment of HSV-1, HCV, IAV, vaccinia virus, adenovirus, reovirus, and vesicular stomatitis virus (VSV) virions. We further show that EGCG competes with heparan sulfate for binding of HSV-1 and HCV virions and with sialic acid for binding of IAV virions. Therefore, EGCG inhibits unrelated viruses by a common mechanism. Most importantly, we have identified EGCG as the first broad-spectrum attachment inhibitor. Our results open the possibility for the development of small molecule broad-spectrum antivirals targeting virion attachment. IMPORTANCE This study shows that it is possible to develop a small molecule antiviral or microbicide active against the two largest groups of human viruses: those that bind to glycosaminoglycans and those that bind to sialoglycans. This group includes the vast majority of human viruses, including herpes simplex viruses, cytomegalovirus, influenza virus, poxvirus, hepatitis C virus, HIV, and many others. PMID

  7. [Magnetophoresis of glutaminic acid and magnesium sulfate in rehabilitation of children with cerebral palsy].

    PubMed

    Gurova, N Iu; Babina, L M

    2007-01-01

    Clinical efficacy of magnetophoresis of glutaminic acid and magnesium sulfate used in the rehabilitative complex for preschool children with spastic forms of cerebral palsy has been studied. The clinical and neurophysiological examination has been conducted in 40 children aged from 1 to 7 years. The higher efficacy of treatment with combination of running pulsed magnetic field and drugs as compared to magnetotherapy using the same procedure has been found. PMID:18427459

  8. Mineral Alteration in Acid-sulfate Fumaroles on Earth and Mars

    NASA Astrophysics Data System (ADS)

    McCollom, T. M.; Hynek, B. M.; Rogers, K. L.

    2011-12-01

    Recent observations made at Mars by orbiting spacecraft and landers have documented the widespread occurrence of sulfate-rich rocks across the planet. Although the settings and origins of these rocks are likely to be variable, at least some appear to have originated from hydrothermal alteration of volcanic rocks. In order to place constraints on the chemical and mineralogical processes that might give rise to sulfate-rich rocks in hydrothermal settings on Mars, we are studying of acid-sulfate alteration of basalt in fumarolic environments using a combination of field work, experiments, and numerical modeling. Examination of acid-sulfate altered basaltic cinders from active fumaroles at Cerro Negro volcano in Nicaragua indicates that the initial stage of alteration results predominantly in the formation of amorphous silica, gypsum, and natroalunite/natrojarosite, with minor amounts of iron oxides/oxyhydroxides. Laboratory experimental alteration of basalt cinders by sulfuric acid at 145 °C generated a similar suite of minerals, with amorphous Si-rich gel, anhydrite, and Fe-bearing natroalunite as the primary products, along with minor amounts of Fe oxides/oxyhydroxides and magnesium sulfates. Crystalline silicates, including clay minerals, are not observed in either the field samples or experimental products. During the initial stage of alteration in both field and laboratory samples, igneous phenocrysts decompose rapidly while the glass remains intact. Over time, cations inlcuding Ca, Mg, Fe, Al, and Na are progressively leached from the glass in the field samples, while the glass largely maintains its original morphology despite being composed predominantly of SiO2. Evaluation of the laboratory and field results with numerical geochemical models indicates that formation of the observed alteration products requires that (a) igneous silicate phenocrysts (plagioclase, augite, olivine) react much faster than basaltic glass and (b) there are kinetic inhibitions to the

  9. Effect of QMix, peracetic acid and ethylenediaminetetraacetic acid on calcium loss and microhardness of root dentine

    PubMed Central

    Taneja, Sonali; Kumari, Manju; Anand, Surbhi

    2014-01-01

    Objectives: The objective of this in vitro study was to assess the effect of different chelating agents on the calcium loss and its subsequent effect on the microhardness of the root dentin. Materials and Methods: Ten single rooted lower premolars were selected. The teeth were decoronated and thick transverse sections of 2 mm were obtained from the coronal third of the root. Each section was then divided into four quarters, each part constituting a sample specimen from the same tooth for each group. The treatment groups were: Group 1 (Control): 5% Sodium hypochlorite (NaOCl) for 5 min + distilled water for 5 min; Group 2: 5% NaOCl for 5 min + 17% ethylenediaminetetraacetic acid (EDTA) for 5 min; Group 3: 5% NaOCl for 5 min + 2.25% Peracetic acid (PAA) for 5 min and Group 4: 5% NaOCl for 5 min + QMix for 5 min respectively. The calcium loss of the samples was evaluated using the Atomic Absorption Spectrophotometer followed by determination of their microhardness using Vickers Hardness Tester. Data was analyzed using one-way ANOVA, Post hoc Tukey test and Pearson correlation. Results: The maximum calcium loss and minimum microhardness was observed in Group 3 followed by Group 2, Group 4 and Group 1. There was a statistically significant difference between all the groups except between Groups 2 and 4. Conclusions: Irrigation with NaOCl + 2.25% PAA caused the maximum calcium loss from root dentin and reduced microhardness. A negative correlation existed between the calcium loss and reduction in the microhardness of root dentin. PMID:24778513

  10. Hydrochemistry of episodic drainage waters discharged from an acid sulfate soil affected catchment

    NASA Astrophysics Data System (ADS)

    Green, R.; Macdonald, B. C. T.; Melville, M. D.; Waite, T. D.

    2006-06-01

    The water quality of drainage discharged via pumping from an acid sulfate soil (ASS) affected catchment used for sugar cane farming is temporally very variable and is influenced by the various rain event magnitudes, their antecedents, and the particular phase of the discharge in any rain event. Rainfall episodes can cause substantial changes in acidity and dissolved metal concentrations in ASS drainage waters over very short time scales with minimum pH often reached within a few hours of initiation of the rainfall event. The initial increase in acidity and dissolved metals concentrations often observed can be attributed mainly to 'first flush' effects resulting from mobilization of salts present in the upper soil profile. During the middle of a large rainfall event dilution effects may result in a decrease in concentrations of dissolved species, but increases in acidity and dissolved metals (particularly aluminium) concentrations in the recession portion of the hydrograph often occur as small field drains discharge into main channels. These observations assist both in understanding of the hydrogeochemical processes leading to acid and metals release from acid sulfate soils affected catchments, and in developing appropriate strategies to treat contaminated discharge waters from such catchments.

  11. 21 CFR 872.3490 - Carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. 872.3490 Section 872.3490 Food and Drugs... maleic acid calcium-sodium double salt denture adhesive. (a) Identification. A carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive is a...

  12. 21 CFR 872.3490 - Carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. 872.3490 Section 872.3490 Food and Drugs... maleic acid calcium-sodium double salt denture adhesive. (a) Identification. A carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive is a...

  13. 21 CFR 872.3490 - Carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. 872.3490 Section 872.3490 Food and Drugs... maleic acid calcium-sodium double salt denture adhesive. (a) Identification. A carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive is a...

  14. 21 CFR 872.3490 - Carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. 872.3490 Section 872.3490 Food and Drugs... maleic acid calcium-sodium double salt denture adhesive. (a) Identification. A carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive is a...

  15. 21 CFR 872.3490 - Carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. 872.3490 Section 872.3490 Food and Drugs... maleic acid calcium-sodium double salt denture adhesive. (a) Identification. A carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive is a...

  16. Effect of L-lactic acid on the absorption of calcium in gastrectomized rats.

    PubMed

    Chonan, O; Takahashi, R; Yasui, H; Watanuki, M

    1998-12-01

    The effect of dietary L-lactic acid (LA), (0.5, 1.0, or 2.5 g/100 g of diet) on the absorption of calcium in gastrectomized rats was evaluated for 28 d. Calcium phosphate was used as a source of calcium. The apparent calcium absorption ratio and the calcium contents of the femur and tibia in gastrectomized rats fed the control diet were significantly less than those in sham-operated rats. In the gastrectomized rats, the apparent calcium absorption ratio and the calcium contents of bone in the rats fed the lower doses of LA diets (LA 0.5 or 1.0 g/100 g of diet) were not affected; however, the apparent calcium absorption ratio and the calcium contents of bone in the rats fed the highest doses of LA diet (LA 2.5 g/100 g of diet) were greater than those in gastrectomized rats fed the control diet. Dietary LA (2.5 g/100 g of diet) also enhanced the phosphorus absorption and bone phosphorus content in the gastrectomized rats. We speculated that the highest dose of dietary LA might be associated with the dissolving of a water-insoluble form of calcium salt in the diet, thereby facilitating the calcium absorption and resulting in increased bone calcium content in gastrectomized rats.

  17. The effects of acid deposition on sulfate reduction and methane production in peatlands

    NASA Technical Reports Server (NTRS)

    Murray, Georgia L.; Hines, Mark E.; Bayley, Suzanne E.

    1992-01-01

    Peatlands, as fens and bods, make up a large percentage of northern latitude terrestrial environments. They are organic rich and support an active community of anaerobic bacteria, such as methanogenic and sulfate-reducing bacteria. The end products of these microbial activities, methane and hydrogen sulfide, are important components in the global biogeochemical cycles of carbon and sulfur. Since these two bacterial groups compete for nutritional substrates, increases in sulfate deposition due to acid rain potentially can disrupt the balance between these processes leading to a decrease in methane production and emission. This is significant because methane is a potent greenhouse gas that effects the global heat balance. A section of Mire 239 in the Experimental Lakes Area, in Northwestern Ontario, was artificially acidified and rates of sulfate reduction and methane production were measured with depth. Preliminary results suggested that methane production was not affected immediately after acidification. However, concentrations of dissolved methane decreased and dissolved sulfide increased greatly after acidification and both took several days to recover. The exact mechanism for the decrease in methane was not determined. Analyses are under way which will be used to determine rates of sulfate reduction. These results will be available by Spring and will be discussed.

  18. Identification of Organic Sulfate Esters in d-Limonene Ozonolysis SOA Under Acidic Condition

    NASA Astrophysics Data System (ADS)

    Iinuma, Y.; Mueller, C.; Boege, O.; Herrmann, H.

    2006-12-01

    Secondary organic aerosol (SOA) components from gas phase ozonolysis of d-limonene were investigated in a series of indoor chamber experiments. The compounds smaller than 300 Da were quantified using capillary electrophoresis coupled to electrospray ionisation ion trap mass spectrometry (CE/ESI-ITMS). HPLC coupled to an ESI-TOFMS and an ESI-ITMS was used for structural study of dimmers and oligomers. Only 10% of the produced SOA could be attributed to low molecular weight carboxylic acids (Mw<300). The oxidation products which have molecular weights over 300 were detected regardless of the seed particle acidity but the concentrations of these compounds were much higher for acidic seed particle experiments. Strong signals of the compounds with mass to charge ratios (m/z) 281, 465 and 481 were detected when sulphuric acid was used in the seed particles. These compounds showed a strong fragment of m/z 97 in MS2 or MS3 spectra indicating the presence of sulfate in the structures. HPLC/ESI-TOFMS analysis suggests the elemental compositions of C10H17O7S-, C20H33O10S- and C20H33O11S- for m/z 281, 465 and 481, respectively. Based on MS^{n} and TOFMS results, they are most likely organic sulfate esters, possibly formed by a heterogeneous acid catalyzed reaction of a limonene oxidation product and sulfuric acid in the particle phase. The concentrations of the organic sulfate ester were as high as 3.7 μgm-3 for m/z 281.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. Sulfated Steroid–Amino Acid Conjugates from the Irish Marine Sponge Polymastia boletiformis

    PubMed Central

    Smyrniotopoulos, Vangelis; Rae, Margaret; Soldatou, Sylvia; Ding, Yuanqing; Wolff, Carsten W.; McCormack, Grace; Coleman, Christina M.; Ferreira, Daneel; Tasdemir, Deniz

    2015-01-01

    Antifungal bioactivity-guided fractionation of the organic extract of the sponge Polymastia boletiformis, collected from the west coast of Ireland, led to the isolation of two new sulfated steroid-amino acid conjugates (1 and 2). Extensive 1D and 2D NMR analyses in combination with quantum mechanical calculations of the electronic circular dichroism (ECD) spectra, optical rotation, and 13C chemical shifts were used to establish the chemical structures of 1 and 2. Both compounds exhibited moderate antifungal activity against Cladosporium cucumerinum, while compound 2 was also active against Candida albicans. Marine natural products containing steroidal and amino acid constituents are extremely rare in nature. PMID:25812034

  1. Acid-Tolerant Sulfate-Reducing Bacteria Play a Major Role in Iron Cycling in Acidic Iron Rich Sediments

    NASA Astrophysics Data System (ADS)

    Enright, K. A.; Moreau, J. W.

    2008-12-01

    Climate change drives drying and acidification of many rivers and lakes. Abundant sedimentary iron in these systems oxidizes chemically and biologically to form iron-ox(yhydrox)ide crusts and "hardpans". Given generally high sulfate concentrations, the mobilization and cycling of iron in these environments can be strongly influenced by bacterial sulfate reduction. Sulfate-reducing bacteria (SRB) induce reductive dissolution of oxidized iron phases by producing the reductant bisulfide as a metabolic product. These environmentally ubiquitous microbes also recycle much of the fixed carbon in sediment-hosted microbial mat communities. With prevalent drying, the buffering capacity for protons liberated from iron oxidation is exceeded, and the activity of sulfate-reducers is restricted to those species capable of tolerating low pH (and generally highly saline, i.e. sulfate-rich) conditions. These species will sustain the recycling of iron from more crystalline phases to more bioavailable species, as well as act as the only source of bisulfide for photosynthesizing microbial communities. The phylogeny and physiology of acid-tolerant SRB is therefore important to Fe, S and C cycling in iron-rich sedimentary environments, particularly those on a geochemical trajectory towards acidification. Previous studies have shown that these SRB species tend to be highly novel. We studied two distinct environments along a geochemical continuum towards acidification. In both settings, iron redox transformations exert a major, if not controlling, influence on reduction potential. An acidified, iron- rich tidal marsh receiving acid-mine drainage (San Francisco Bay, CA, USA) contained abundant textural evidence for reductive dissolution of Fe(III) in sediments with pH values varying from 2.4 - 3.8. From these sediments, full-length novel dsrAB gene sequences from acid-tolerant SRB were recovered, and sulfur isotope profiles reflected biological fractionation of sulfur under even the most

  2. A Geochemical and Mineralogical Model for Formation of Layered Sulfate Deposits at Meridiani Planum by Hydrothermal Acid-sulfate Alteration of Pyroclastic Basalt

    NASA Astrophysics Data System (ADS)

    McCollom, T. M.; Hynek, B. M.

    2012-12-01

    The Mars Exploration Rover (MER) Opportunity has extensively characterized sulfate-rich, hematite-bearing bedrock exposed at Meridiani Planum, Mars. Based on various measurements, the mineral composition of the bedrocks has been interpreted to include: amorphous silica/glass/phyllosilicates, Mg-, Ca-, and Fe-bearing sulfates including jarosite, minor amounts of igneous phases including plagioclase, pyroxene, olivine, and magnetite, and hematite [1,2]. Chemically, the bedrocks closely resemble the composition of pristine martian basalt with addition of S and O, and minor variations of Mg and Cl with depth [3,4]. Based on these and other observations, the MER team has proposed that the bedrocks represent chemically altered siliciclastic sediments combined with sulfate salts formed by evaporation of sulfate-bearing fluids, modified by transport and multiple stages of infiltrating groundwater [3,5]. Several alternative scenarios have been proposed for the origin of the rocks including large impacts [6], evaporating glacial deposits [7], acid-fog alteration [8], and hydrothermal acid-sulfate alteration of basalt [4]. In order to further evaluate the potential contribution of hydrothermal proceeses to the deposits, we performed numerical geochemical models of acid-sulfate alteration of martian basalt based on constraints provided by recent laboratory experiments. Experimental studies of alteration of basalt conducted in our lab [9] indicate that the initial stages of acid-sulfate alteration of pyroclastic basalt are characterized by rapid decomposition of igneous crystalline phases including plagioclase, pyroxene, and olivine, while the glass (and igneous phases protected within the glass) remain unreactive. Elements released by dissolving minerals are precipitated primarily as amorphous silica and Ca-, Al-, Fe- and Mg-bearing sulfates, while precipitation of phyllosilicates and Fe-oxides/oxyhydroxides (FeOx) is kinetically inhibited. Based on these constraints, models

  3. Mechanistic modeling of biocorrosion caused by biofilms of sulfate reducing bacteria and acid producing bacteria.

    PubMed

    Xu, Dake; Li, Yingchao; Gu, Tingyue

    2016-08-01

    Biocorrosion is also known as microbiologically influenced corrosion (MIC). Most anaerobic MIC cases can be classified into two major types. Type I MIC involves non-oxygen oxidants such as sulfate and nitrate that require biocatalysis for their reduction in the cytoplasm of microbes such as sulfate reducing bacteria (SRB) and nitrate reducing bacteria (NRB). This means that the extracellular electrons from the oxidation of metal such as iron must be transported across cell walls into the cytoplasm. Type II MIC involves oxidants such as protons that are secreted by microbes such as acid producing bacteria (APB). The biofilms in this case supply the locally high concentrations of oxidants that are corrosive without biocatalysis. This work describes a mechanistic model that is based on the biocatalytic cathodic sulfate reduction (BCSR) theory. The model utilizes charge transfer and mass transfer concepts to describe the SRB biocorrosion process. The model also includes a mechanism to describe APB attack based on the local acidic pH at a pit bottom. A pitting prediction software package has been created based on the mechanisms. It predicts long-term pitting rates and worst-case scenarios after calibration using SRB short-term pit depth data. Various parameters can be investigated through computer simulation.

  4. Preparation of metal-resistant immobilized sulfate reducing bacteria beads for acid mine drainage treatment.

    PubMed

    Zhang, Mingliang; Wang, Haixia; Han, Xuemei

    2016-07-01

    Novel immobilized sulfate-reducing bacteria (SRB) beads were prepared for the treatment of synthetic acid mine drainage (AMD) containing high concentrations of Fe, Cu, Cd and Zn using up-flow anaerobic packed-bed bioreactor. The tolerance of immobilized SRB beads to heavy metals was significantly enhanced compared with that of suspended SRB. High removal efficiencies of sulfate (61-88%) and heavy metals (>99.9%) as well as slightly alkaline effluent pH (7.3-7.8) were achieved when the bioreactor was fed with acidic influent (pH 2.7) containing high concentrations of multiple metals (Fe 469 mg/L, Cu 88 mg/L, Cd 92 mg/L and Zn 128 mg/L), which showed that the bioreactor filled with immobilized SRB beads had tolerance to AMD containing high concentrations of heavy metals. Partially decomposed maize straw was a carbon source and stabilizing agent in the initial phase of bioreactor operation but later had to be supplemented by a soluble carbon source such as sodium lactate. The microbial community in the bioreactor was characterized by denaturing gradient gel electrophoresis (DGGE) and sequencing of partial 16S rDNA genes. Synergistic interaction between SRB (Desulfovibrio desulfuricans) and co-existing fermentative bacteria could be the key factor for the utilization of complex organic substrate (maize straw) as carbon and nutrients source for sulfate reduction.

  5. Treatment of acid rock drainage using a sulfate-reducing bioreactor with zero-valent iron.

    PubMed

    Ayala-Parra, Pedro; Sierra-Alvarez, Reyes; Field, James A

    2016-05-01

    This study assessed the bioremediation of acid rock drainage (ARD) in flow-through columns testing zero-valent iron (ZVI) for the first time as the sole exogenous electron donor to drive sulfate-reducing bacteria in permeable reactive barriers. Columns containing ZVI, limestone or a mixture of both materials were inoculated with an anaerobic mixed culture and fed a synthetic ARD containing sulfuric acid and heavy metals (initially copper, and later also cadmium and lead). ZVI significantly enhanced sulfate reduction and the heavy metals were extensively removed (>99.7%). Solid-phase analyses showed that heavy metals were precipitated with biogenic sulfide in the columns packed with ZVI. Excess sulfide was sequestered by iron, preventing the discharge of dissolved sulfide. In the absence of ZVI, heavy metals were also significantly removed (>99.8%) due to precipitation with hydroxide and carbonate ions released from the limestone. Vertical-profiles of heavy metals in the columns packing, at the end of the experiment, demonstrated that the ZVI columns still had excess capacity to remove heavy metals, while the capacity of the limestone control column was approaching saturation. The ZVI provided conditions that enhanced sulfate reduction and generated alkalinity. Collectively, the results demonstrate an innovative passive ARD remediation process using ZVI as sole electron-donor. PMID:26808248

  6. Preparation of metal-resistant immobilized sulfate reducing bacteria beads for acid mine drainage treatment.

    PubMed

    Zhang, Mingliang; Wang, Haixia; Han, Xuemei

    2016-07-01

    Novel immobilized sulfate-reducing bacteria (SRB) beads were prepared for the treatment of synthetic acid mine drainage (AMD) containing high concentrations of Fe, Cu, Cd and Zn using up-flow anaerobic packed-bed bioreactor. The tolerance of immobilized SRB beads to heavy metals was significantly enhanced compared with that of suspended SRB. High removal efficiencies of sulfate (61-88%) and heavy metals (>99.9%) as well as slightly alkaline effluent pH (7.3-7.8) were achieved when the bioreactor was fed with acidic influent (pH 2.7) containing high concentrations of multiple metals (Fe 469 mg/L, Cu 88 mg/L, Cd 92 mg/L and Zn 128 mg/L), which showed that the bioreactor filled with immobilized SRB beads had tolerance to AMD containing high concentrations of heavy metals. Partially decomposed maize straw was a carbon source and stabilizing agent in the initial phase of bioreactor operation but later had to be supplemented by a soluble carbon source such as sodium lactate. The microbial community in the bioreactor was characterized by denaturing gradient gel electrophoresis (DGGE) and sequencing of partial 16S rDNA genes. Synergistic interaction between SRB (Desulfovibrio desulfuricans) and co-existing fermentative bacteria could be the key factor for the utilization of complex organic substrate (maize straw) as carbon and nutrients source for sulfate reduction. PMID:27058913

  7. Magnesium, calcium and strontium salts of phenylacetic acid.

    PubMed

    Arlin, Jean Baptiste; Kennedy, Alan R; Shankland, Kenneth

    2012-02-01

    Three alkaline earth metal salts of phenylacetic acid were examined and all were found to have similar structural types to analogous salts of benzoic and halobenzoic acids. Thus, a synchrotron study shows that the cations in catena-poly[[[tetraaquamagnesium(II)]-μ-phenylacetato-κ(2)O:O'] phenylacetate], {[Mg(C(8)H(7)O(2))(H(2)O)(4)](C(8)H(7)O(2))}(n), form a one-dimensional coordination polymer that propagates through Mg-O-C-O-Mg interactions involving both crystallographically independent Mg centres (Z' = 2) and through translation along the a axis. The polymeric chains pack to give alternate inorganic layers and organic bilayers. The Ca and Sr species catena-poly[[[diaqua(phenylacetato-κ(2)O,O')calcium(II)]-μ(3)-phenylacetato-1':1:1''κ(4)O:O,O':O'] monohydrate], {[Ca(C(8)H(7)O(2))(2)(H(2)O)(2)]·H(2)O}(n), and catena-poly[[[diaqua(phenylacetato-κ(2)O,O')strontium(II)]-μ(3)-phenylacetato-1':1:1''κ(4)O:O,O':O'] monohydrate], {[Sr(C(8)H(7)O(2))(2)(H(2)O)(2)]·H(2)O}(n), are essentially isostructural. Both form one-dimensional coordination polymers through a carboxylate group that forms four M-O bonds. The polymeric chains propagate via 2(1) screw axes parallel to the b axis and are further linked in the bc plane by hydrogen bonding involving the non-metal-bound water molecule. Similarly to the Mg salt, both have inorganic layers that alternate with organic bilayers. PMID:22307244

  8. Study on Treatment of acidic and highly concentrated fluoride waste water using calcium oxide-calcium chloride

    NASA Astrophysics Data System (ADS)

    Ren, T.; Gao, X. R.; Zheng, T.; Wang, P.

    2016-08-01

    There are problems with treating acidic waste water containing high concentration fluorine by chemical precipitation, including the low sludge setting velocity and the high difficulty of reaching the criterion. In Heilongjiang province, a graphite factory producing high-purity graphite generates acidic waste water with a high concentration of fluorine. In this paper, the effect of removals on the concentration of fluoride with the combined treatment of calcium oxide and calcium chloride were discussed with regard to acid waste water. The study improved the sludge characteristics by using polyacrylamide (PAM) and polymeric aluminum chloride (PAC). The effect of different coagulants on sludge was evaluated by the sludge settlement ratio (SV), sludge volume index (SVI) and sludge moisture content. The results showed that the optimal combination for 100 ml waste water was calcium oxide addition amount of 14 g, a calcium chloride addition amount of 2.5 g, a PAM addition amount of 350 mg/L, and the effluent fluoride concentration was below 6 mg/L. PAM significantly improved the sludge settling velocity. The sludge settlement ratio reduced from 87.6% to 60%. The process for wastewater treatment was easily operated and involved low expenditure.

  9. Acid Mine Drainage and Metal Sulfate Minerals in the Shasta Mining District, California

    NASA Astrophysics Data System (ADS)

    Livingston, J. D.; Murphy, W. M.; Miller, R. M.; Ayars, E. J.

    2005-12-01

    Metal sulfate minerals were collected at four surface water drainage sites during September and October of 2004 in the Shasta Mining District, southern Klamath Mountains, Shasta County, California and analyzed by X-ray fluorescence, atomic absorption spectroscopy, and X-ray diffraction to determine elements present, quantities of Fe, Cu, and Zn, and mineralogy. The Shasta Mining District produced major quantities of Cu, Zn, and pyrite (S) with minor amounts of Au, Ag, and Fe from massive sulfide bodies (Kinkel et al., 1956). Three study sites are located on Iron Mountain and one study site is at Bully Hill. Although mining occurred during a period of just over 100 years, it is estimated that acid mine drainage (AMD) will continue from Iron Mountain for over 3,200 years (Nordstrom and Alpers, 1998). AMD at the study sites produces blooms of metal sulfates during California's Mediterranean climate summer. The minerals readily dissolve in the "first flush" of seasonal rain creating runoff water of low pH with high amounts of dissolved metals (Bayless and Olyphant, 1993; Jambor et al., 2000). Data were examined for mineralogical changes in time and space and for zoning of minerals on a scale of centimeters. Sulfate mineral samples are complex with some samples composed of over a dozen different minerals. Site 1 is located on Spring Creek downstream from the Iron Mountain superfund remediation site, so levels of Fe, Cu, and Zn in the sulfates at this site are lower than at the other sites. Two site 1 samples from the same location taken a month apart show Ca, Fe, Cu, Sr, Y, and Sn, and the first sample also has detectable Br. The metal sulfates identified from the first visit are celestine, cesanite, chessexite, hectorfloresite, and ungemachite, and the mineralogy of the second visit is bilinite, epsomite, millosevichite, and anhydrite. The Fe bearing sulfate mineral during the first visit is ungemachite, but bilinite was the Fe bearing mineral at the time of the second

  10. NONLINEARITIES IN THE SULFATE SECONDARY FINE PARTICULATE RESPONSE TO NOX EMISSIONS REDUCTIONS AS MODELED BY THE REGIONAL ACID DEPOSITION MODEL

    EPA Science Inventory

    Attention is increasingly being devoted to the health effects of fine particulates. In regions that have a large production of sulfate, sulfuric acid and nitric acid compete for the available ammonia to form aerosols. In addition, the available nitric acid is the result of ur...

  11. Acid diet (high meat protein) effects on calcium metabolism and bone health

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Purpose of review: Update recent advancements regarding the effect of high animal protein on calcium utilization and bone health. Recent findings: Increased potential renal acid load resulting from a high protein (meat) intake has been closely associated with increased urinary calcium excretion. How...

  12. Dermatitis, branchitis and mortality in empire gudgeon Hypseleotris compressa exposed naturally to runoff from acid sulfate soils.

    PubMed

    Callinan, R B; Sammut, J; Fraser, G C

    2005-02-28

    Severe dermatitis and branchitis are described in a wild population of empire gudgeon Hypseleotris compressa, an Australian eleotrid, exposed naturally to runoff from acid sulfate soils (ASS) in a drained estuarine embayment in eastern Australia. After at least 2 d exposure to pH < 4, and up to 7 d exposure to pH < 6, approximately 50% of the fish sampled had moderate to severe diffuse epidermal hyperplasia, usually at scale margins, and scattered areas of moderate to severe, focal to locally extensive, subacute, necrotising dermatitis. Saprolegnia spp. had invaded epidermis in some inflamed areas. In gills, there was moderate to severe hyperplasia and necrosis of secondary lamellar epithelium, with fusion of adjacent secondary lamellae. Inorganic monomeric aluminium and calcium concentrations in water at the site during the event were 27.7 and 16.6 mg l(-1), respectively. Large numbers of empire gudgeons at the study site had died after at least 8 d exposure to pH < 4, and up to 13 d exposure to pH < 6. These findings provide clear evidence that acidification of estuarine systems by runoff from ASS has deleterious effects on aquatic biota. Furthermore, study findings suggest a mechanism whereby lesions of epizootic ulcerative syndrome (EUS) may be initiated in estuarine fishes by a combination of sublethal exposure to ASS runoff and Aphanomyces invadans infection, a suggestion consistent with the geographic and temporal distribution of EUS outbreaks in Australian estuaries.

  13. Microbial sulfate reduction and metal attenuation in pH 4 acid mine water

    PubMed Central

    Church, Clinton D; Wilkin, Richard T; Alpers, Charles N; Rye, Robert O; McCleskey, R Blaine

    2007-01-01

    Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4.0 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing bacteria (SRB) were active in moderately acidic conditions present in the underground mine workings. Here we document multiple, independent analyses and show evidence that sulfate reduction and associated metal attenuation are occurring in the pH-4 mine environment. Water-chemistry analyses of the mine water reveal: (1) preferential complexation and precipitation by H2S of Cu and Cd, relative to Zn; (2) stable isotope ratios of 34S/32S and 18O/16O in dissolved SO4 that are 2–3 ‰ heavier in the mine water, relative to those in surface waters; (3) reduction/oxidation conditions and dissolved gas concentrations consistent with conditions to support anaerobic processes such as sulfate reduction. Scanning electron microscope (SEM) analyses of sediment show 1.5-micrometer, spherical ZnS precipitates. Phospholipid fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analyses of Penn Mine sediment show a high biomass level with a moderately diverse community structure composed primarily of iron- and sulfate-reducing bacteria. Cultures of sediment from the mine produced dissolved sulfide at pH values near 7 and near 4, forming precipitates of either iron sulfide or elemental sulfur. DGGE coupled with sequence and phylogenetic analysis of 16S rDNA gene segments showed populations of Desulfosporosinus and Desulfitobacterium in Penn Mine sediment and laboratory cultures. PMID:17956615

  14. Microbial sulfate reduction and metal attenuation in pH 4 acid mine water

    USGS Publications Warehouse

    Church, C.D.; Wilkin, R.T.; Alpers, C.N.; Rye, R.O.; Blaine, R.B.

    2007-01-01

    Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4.0 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing bacteria (SRB) were active in moderately acidic conditions present in the underground mine workings. Here we document multiple, independent analyses and show evidence that sulfate reduction and associated metal attenuation are occurring in the pH-4 mine environment. Water-chemistry analyses of the mine water reveal: (1) preferential complexation and precipitation by H2S of Cu and Cd, relative to Zn; (2) stable isotope ratios of 34S/32S and 18O/16O in dissolved SO4 that are 2-3 ??? heavier in the mine water, relative to those in surface waters; (3) reduction/oxidation conditions and dissolved gas concentrations consistent with conditions to support anaerobic processes such as sulfate reduction. Scanning electron microscope (SEM) analyses of sediment show 1.5-micrometer, spherical ZnS precipitates. Phospholipid fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analyses of Penn Mine sediment show a high biomass level with a moderately diverse community structure composed primarily of iron- and sulfate-reducing bacteria. Cultures of sediment from the mine produced dissolved sulfide at pH values near 7 and near 4, forming precipitates of either iron sulfide or elemental sulfur. DGGE coupled with sequence and phylogenetic analysis of 16S rDNA gene segments showed populations of Desulfosporosinus and Desulfitobacterium in Penn Mine sediment and laboratory cultures. ?? 2007 Church et al; licensee BioMed Central Ltd.

  15. Effect of A Long Chain Carboxylate Acid on Sodium Dodecyl Sulfate Micelle Structure: A SANS Study

    NASA Astrophysics Data System (ADS)

    Patriati, Arum; Giri Rachman Putra, Edy; Seok Seong, Baek

    2010-01-01

    The effect of a different hydrocarbon chain length of carboxylate acid, i.e. dodecanoic acid, CH3(CH)10COOH or lauric acid and hexadecanoic acid, CH3(CH2)14COOH or palmitic acid as a co-surfactant in the 0.3 M sodium dedecyl sulfate, SDS micellar solution has been studied using small angle neutron scattering (SANS). The present of lauric acid has induced the SDS structural micelles. The ellipsoid micelles structures changed significantly in length (major axis) from 22.6 Å to 37.1 Å at a fixed minor axis of 16.7 Å in the present of 0.005 M to 0.1 M lauric acid. Nevertheless, this effect did not occur in the present of palmitic acid with the same concentration range. The present of palmitic acid molecules performed insignificant effect on the SDS micelles growth where the major axis of the micelle was elongated from 22.9 Å to 25.3 Å only. It showed that the appropriate hydrocarbon chain length between surfactant and co-surfactant molecules emerged as one of the determining factors in forming a mixed micelles structure.

  16. Calcium

    MedlinePlus

    ... milligrams) of calcium each day. Get it from: Dairy products. Low-fat milk, yogurt, cheese, and cottage ... lactase that helps digest the sugar (lactose) in dairy products, and may have gas, bloating, cramps, or ...

  17. Calcium

    MedlinePlus

    ... supplements and fortified foods include gluconate, lactate, and phosphate. Calcium absorption is best when a person consumes ... also interfere with the body's ability to absorb iron and zinc, but this effect is not well ...

  18. Silver-silver sulfate reference electrodes for use in lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Ruetschi, Paul

    Electrochemical properties of silver-silver sulfate reference electrodes for lead-acid batteries are described, and the following possible applications discussed: Determination of individual capacities of positive and negative plates. Monitoring individual electrode behavior during deep discharge and cell reversal. Optimization charge or discharge parameters, by controlling the current such that pre-determined limits of positive or negative half-cell potential are respected. Observation of acid concentration differences, for example due to acid stratification, by measuring diffusion potentials (concentration-cell voltages). Detection of defective cells, and defective plate sets, in a string of cells, at the end of their service life. Silver-silver sulfate reference electrodes, permanently installed in lead-acid cells, may be a means to improve battery management, and therewith to improve reliability and service life. In vented batteries, reference electrodes may be used to limit positive plate polarization during charge, or float-charge. Limiting the positive half-cell potential to an upper, pre-set value would permit to keep anodic corrosion as low as possible. During cycling, discharge could be terminated when the half-cell potential of the positive electrode has dropped to a pre-set limit. This would prevent excessive discharge of the positive electrodes, which could result in an improvement of cycle life. In valve-regulated batteries, reference electrodes may be used to adjust float-charge conditions such as to assure sufficient cathodic polarization of the negative electrodes, in order to avoid sulfation. The use of such reference electrodes could be beneficial particularly in multi-cell batteries, with overall voltages above 12 V, operated in a partial-state-of-charge.

  19. Houttuyniae Herba Attenuates Kainic Acid-Induced Neurotoxicity via Calcium Response Modulation in the Mouse Hippocampus.

    PubMed

    Kim, Hyo Geun; Jeong, Hyun Uk; Hong, Sung In; Oh, Myung Sook

    2015-12-01

    Epilepsy is a complex neurological disorder characterized by the repeated occurrence of electrical activity known as seizures. This activity induces increased intracellular calcium, which ultimately leads to neuronal damage. Houttuyniae Herba, the aerial part of Houttuynia cordata, has various pharmacological effects and is widely used as a traditional herb. In the present study, we evaluated the protective effects of Houttuyniae Herba water extract on kainic acid-induced neurotoxicity. Kainic acid directly acts on calcium release, resulting in seizure behavior, neuronal damage, and cognitive impairment. In a rat primary hippocampal culture system, Houttuyniae Herba water extract significantly protected neuronal cells from kainic acid toxicity. In a seizure model where mice received intracerebellar kainic acid injections, Houttuyniae Herba water extract treatment resulted in a lower seizure stage score, ameliorated cognitive impairment, protected neuronal cells against kainic acid-induced toxicity, and suppressed neuronal degeneration in the hippocampus. In addition, Houttuyniae Herba water extract regulated increases in the intracellular calcium level, its related downstream pathways (reactive oxygen species production and mitochondrial dysfunction), and calcium/calmodulin complex kinase type II immunoreactivity in the mouse hippocampus, which resulted from calcium influx stimulation induced by kainic acid. These results demonstrate the neuroprotective effects of Houttuyniae Herba water extract through inhibition of calcium generation in a kainic acid-induced epileptic model. PMID:26366753

  20. Effects of an Al3+- and Mg2+-containing antacid, ferrous sulfate, and calcium carbonate on the absorption of nemonoxacin (TG-873870) in healthy Chinese volunteers

    PubMed Central

    Zhang, Yi-fan; Dai, Xiao-jian; Wang, Ting; Chen, Xiao-yan; Liang, Li; Qiao, Hua; Tsai, Cheng-yuan; Chang, Li-wen; Huang, Ping-ting; Hsu, Chiung-yuan; Chang, Yu-ting; Tsai, Chen-en; Zhong, Da-fang

    2014-01-01

    Aim: To evaluate the effects of an Al3+- and Mg2+-containing antacid, ferrous sulfate, and calcium carbonate on the absorption of nemonoxacin in healthy humans. Methods: Two single-dose, open-label, randomized, crossover studies were conducted in 24 healthy male Chinese volunteers (12 per study). In Study 1, the subjects orally received nemonoxacin (500 mg) alone, or an antacid (containing 318 mg of Al3+ and 496 mg of Mg2+) plus nemonoxacin administered 2 h before, concomitantly or 4 h after the antacid. In Study 2, the subjects orally received nemonoxacin (500 mg) alone, or nemonoxacin concomitantly with ferrous sulfate (containing 60 mg of Fe2+) or calcium carbonate (containing 600 mg of Ca2+). Results: Concomitant administration of nemonoxacin with the antacid significantly decreased the area under the concentration-time curve from time 0 to infinity (AUC0–∞) for nemonoxacin by 80.5%, the maximum concentration (Cmax) by 77.8%, and urine recovery (Ae) by 76.3%. Administration of nemonoxacin 4 h after the antacid decreased the AUC0–∞ for nemonoxacin by 58.0%, Cmax by 52.7%, and Ae by 57.7%. Administration of nemonoxacin 2 h before the antacid did not affect the absorption of nemonoxacin. Administration of nemonoxacin concomitantly with ferrous sulfate markedly decreased AUC0–∞ by 63.7%, Cmax by 57.0%, and Ae by 59.7%, while concomitant administration of nemonoxacin with calcium carbonate mildly decreased AUC0–∞ by 17.8%, Cmax by 14.3%, and Ae by 18.4%. Conclusion: Metal ions, Al3+, Mg2+, and Fe2+ markedly decreased the absorption of nemonoxacin in healthy Chinese males, whereas Ca2+ had much weaker effects. To avoid the effects of Al3+ and Mg2+-containing drugs, nemonoxacin should be administered ≥2 h before them. PMID:25327812

  1. Ultrasound-assisted/biosurfactant-templated size-tunable synthesis of nano-calcium sulfate with controllable crystal morphology.

    PubMed

    Hazra, Chinmay; Bari, Sarang; Kundu, Debasree; Chaudhari, Ambalal; Mishra, Satyendra; Chatterjee, Aniruddha

    2014-05-01

    Nano-sized crystals of alpha calcium sulfate hemihydrate (α-HH) with considerable morphology-dependent properties find promising applications in the clinical fields as a cementitious material. Towards this end, ultrasound-assisted rhamnolipid and surfactin biosurfactant-template route is explored to control the morphology and aspect ratio of nano-CaSO4 by adjusting the mass ratio of rhamnolipid/H2O, surfactin/H2O and rhamnolipid/surfactin. The change in the molar ratio of [SO4(2-)]:[Ca(2+)] results in modification in variable morphology and size of nano-CaSO4 including long, short rods and nanoplates. With increase in the rhamnolipid/H2O ratio from 1.3 to 4.5, the crystal length decreases from 3 μm to 600 nm with the corresponding aspect ratio reduced sharply from 10 to 3. Similarly, the crystal morphology gradually changes from submicrometer-sized long rod to hexagonal plate, and then plate-like appearance with increase in surfactin concentration. The preferential adsorption of rhamnolipid on the side facets and surfactin on the top facets contributes to the morphology control. The process using 50% amplitude with a power input of 45.5 W was found to be the most ideal as observed from the high yields and lower average l/w aspect ratio, leading to more than 94% energy savings as compared to that utilized by the conventional process. As a morphology and crystal habit modifier, effects of Mg(2+) and K(+) ions on α-HH growth were investigated to find an optimal composition of solution for α-HH preparation. Mg(2+) ions apparently show an accelerating effect on the α-HH growth; however, the nucleation of α-HH is probably retarded by K(+) ions. Thus, the present work is a simple, versatile, highly efficient approach to controlling the morphology of α-HH and thereby, offers more opportunities for α-HH multiple applications.

  2. Preparation and physical characterization of calcium sulfate cement/silica-based mesoporous material composites for controlled release of BMP-2.

    PubMed

    Tan, Honglue; Yang, Shengbing; Dai, Pengyi; Li, Wuyin; Yue, Bing

    2015-01-01

    As a commonly used implant material, calcium sulfate cement (CSC), has some shortcomings, including low compressive strength, weak osteoinduction capability, and rapid degradation. In this study, silica-based mesoporous materials such as SBA-15 were synthesized and combined with CSC to prepare CSC/SBA-15 composites. The properties of SBA-15 were characterized by X-ray diffraction, transmission electron microscopy, and nitrogen adsorption-desorption isotherms. SBA-15 was blended into CSC at 0, 5, 10, and 20 wt%, referred to as CSC, CSC-5S (5% mass ratio), CSC-10S (10% mass ratio), and CSC-20S (20% mass ratio), respectively. Fourier-transform infrared spectroscopy and compression tests were used to determine the structure and mechanical properties of the composites, respectively. The formation of hydroxyapatite on composite surfaces was analyzed using scanning electron microscopy and X-ray diffraction after soaking in simulated body fluid. BMP-2 was loaded into the composites by vacuum freeze-drying, and its release characteristics were detected by Bradford protein assay. The in vitro degradation of the CSC/SBA-15 composite was investigated by measuring weight loss. The results showed that the orderly, nanostructured, mesoporous SBA-15 possessed regular pore size and structure. The compressive strength of CSC/SBA-15 increased with the increase in SBA-15 mass ratio, and CSC-20S demonstrated the maximum strength. Compared to CSC, hydroxyapatite that formed on the surfaces of CSC/SBA-15 was uniform and compact. The degradation rate of CSC/SBA-15 decreased with increasing mass ratio of SBA-15. The adsorption of BMP-2 increased and released at a relatively slow rate; the release rate of BMP-2 in CSC-20S was the slowest, and presented characteristics of low doses of release. In vitro experiments demonstrated that the physical properties of pure CSC incorporated with SBA-15 could be improved significantly, which made the CSC/SBA-15 composite more suitable for bone repair

  3. The crystal growth kinetics of alpha calcium sulfate hemihydrate in concentrated CaCl2-HCl solutions

    NASA Astrophysics Data System (ADS)

    Feldmann, Thomas; Demopoulos, George P.

    2012-07-01

    The crystal growth kinetics of calcium sulfate α-hemihydrate (α-HH) in nearly constant supersaturated HCl-CaCl2 solutions were investigated. Two types of solutions were used, the first had a low HCl (1.4 mol/L) and high CaCl2 (2.8 mol/L) concentration and the second had a high HCl (5.6 mol/L) and low CaCl2 (0.7 mol/L) concentration. These conditions were chosen to represent the first and last stage of a newly developed stage-wise HCl regeneration process. The seeded growth experiments were carried out in a stirred, temperature controlled semi-batch reactor in which supersaturation was kept constant by simultaneous addition of CaCl2 and Na2SO4 solutions. The influence of the following parameters on α-HH crystal growth was studied: temperature (70-95 °C), specific power input of stirring (0.02-1.29 W/kg) and equimolar inflow rate of CaCl2 and Na2SO4 (0-0.6 mol/h). The crystal growth rate was derived from particle size distribution measurements made with the laser light diffraction technique. It was found that the surface area normalized crystal growth rate increased linearly with the molar inflow rate up to 0.3 mol/h, at higher inflow rates no further increase of the growth rate was observed. Temperature and specific power input, within the investigated ranges, did not show a marked effect on the growth rate, attributable to a diffusion/adsorption controlled growth process. An interesting finding of the present research is the establishment of a positive relationship between the narrowing of the width of the particle size distribution with increasing crystal growth rate. The results show that the resulting particle size distribution is positively related to the reagent inflow rate, a finding that can be applied to the industrial design and scale-up of the α-HH crystallization/HCl regeneration process.

  4. Preparation and physical characterization of calcium sulfate cement/silica-based mesoporous material composites for controlled release of BMP-2

    PubMed Central

    Tan, Honglue; Yang, Shengbing; Dai, Pengyi; Li, Wuyin; Yue, Bing

    2015-01-01

    As a commonly used implant material, calcium sulfate cement (CSC), has some shortcomings, including low compressive strength, weak osteoinduction capability, and rapid degradation. In this study, silica-based mesoporous materials such as SBA-15 were synthesized and combined with CSC to prepare CSC/SBA-15 composites. The properties of SBA-15 were characterized by X-ray diffraction, transmission electron microscopy, and nitrogen adsorption–desorption isotherms. SBA-15 was blended into CSC at 0, 5, 10, and 20 wt%, referred to as CSC, CSC-5S (5% mass ratio), CSC-10S (10% mass ratio), and CSC-20S (20% mass ratio), respectively. Fourier-transform infrared spectroscopy and compression tests were used to determine the structure and mechanical properties of the composites, respectively. The formation of hydroxyapatite on composite surfaces was analyzed using scanning electron microscopy and X-ray diffraction after soaking in simulated body fluid. BMP-2 was loaded into the composites by vacuum freeze-drying, and its release characteristics were detected by Bradford protein assay. The in vitro degradation of the CSC/SBA-15 composite was investigated by measuring weight loss. The results showed that the orderly, nanostructured, mesoporous SBA-15 possessed regular pore size and structure. The compressive strength of CSC/SBA-15 increased with the increase in SBA-15 mass ratio, and CSC-20S demonstrated the maximum strength. Compared to CSC, hydroxyapatite that formed on the surfaces of CSC/SBA-15 was uniform and compact. The degradation rate of CSC/SBA-15 decreased with increasing mass ratio of SBA-15. The adsorption of BMP-2 increased and released at a relatively slow rate; the release rate of BMP-2 in CSC-20S was the slowest, and presented characteristics of low doses of release. In vitro experiments demonstrated that the physical properties of pure CSC incorporated with SBA-15 could be improved significantly, which made the CSC/SBA-15 composite more suitable for bone repair

  5. Analysis of the erosive potential of calcium-containing acidic beverages.

    PubMed

    Hara, Anderson T; Zero, Domenick T

    2008-02-01

    The occurrence and progress of enamel demineralization may be reduced in the presence of its reaction products, such as calcium. Therefore, in this study the hypothesis that lower erosive potential may be expected for calcium-containing beverages was tested. Ten commercially available beverages, five with and five without calcium supplementation, were tested in two phases. In the first phase, the pH, titratable acidity, and concentrations of calcium (total and ionic), phosphorus and fluoride, were analyzed. In the second phase, the ability of the test products to erode enamel was measured, at different time-points. Within the chemical properties tested, pH, calcium-ion concentration, and total calcium showed a strong correlation with enamel demineralization and enamel wear. Lower levels of enamel demineralization and wear were found for most of the calcium-containing beverages than for those without calcium. Calcium-ion content, as well as pH, were found to be good predictors of the erosive potential of the beverages tested. Generally, beverages supplemented with calcium had a reduced capacity to demineralize enamel.

  6. Synthesis of a sulfonic acid mimetic of the sulfated Lewis A pentasaccharide.

    PubMed

    Jakab, Zsolt; Fekete, Anikó; Csávás, Magdolna; Borbás, Anikó; Lipták, András; Antus, Sándor

    2012-03-01

    The first sulfonic acid mimetic of the sulfated Lewis A pentasaccharide in which the natural L-fucose unit is replaced by a D-arabinose ring was synthesized. Formation of the sulfonic acid moiety at a pentasaccharide level could be successfully achieved by means of introduction of an acetylthio moiety into the terminal D-galactose residue and subsequent oxidation. The equatorial arrangement of the acetylthio group linked to C-3 of the galactose ring could be obtained by double nucleophilic substitutions; efficient formation of the gulo-triflate derivatives required low-power microwave (MW) activation. Oxidation of the acetylthio group was carried out using Oxone in the presence of acetic acid.

  7. Supported zirconium sulfate on carbon nanotubes as water-tolerant solid acid catalyst

    SciTech Connect

    Juan, Joon Ching; Jiang Yajie; Meng Xiujuan; Cao Weiliang; Yarmo, Mohd Ambar; Zhang Jingchang . E-mail: zhangjc1@mail.buct.edu.cn

    2007-07-03

    A new solid acid of zirconium sulfate (CZ) was successfully supported on carbon nanotube (CNT) for esterification reaction. Preparation conditions of the supported CZ have been investigated, to obtain highest catalytic activity for esterification reaction. XRD, TEM, BET, X-ray photoelectron spectra (XPS) and in situ FTIR analysis has also been carried out to understand the characteristics of the catalyst. In the esterification of acrylic acid with n-octanol, the supported CZ exhibited high catalytic activity and stability. The catalytic activity was nearly unchanged during four times of reuse. XRD and TEM analysis indicated that CZ was finely dispersed on CNT. XPS analysis shows that the CZ species was preserved and the chemical environment of the CZ has changed after loaded on CNT. This finding show that CNT as CZ support is an efficient water-tolerant solid acid.

  8. Ulvan, a Sulfated Polysaccharide from Green Algae, Activates Plant Immunity through the Jasmonic Acid Signaling Pathway

    PubMed Central

    Jaulneau, Valérie; Lafitte, Claude; Jacquet, Christophe; Fournier, Sylvie; Salamagne, Sylvie; Briand, Xavier; Esquerré-Tugayé, Marie-Thérèse; Dumas, Bernard

    2010-01-01

    The industrial use of elicitors as alternative tools for disease control needs the identification of abundant sources of them. We report on an elicitor obtained from the green algae Ulva spp. A fraction containing most exclusively the sulfated polysaccharide known as ulvan-induced expression of a GUS gene placed under the control of a lipoxygenase gene promoter. Gene expression profiling was performed upon ulvan treatments on Medicago truncatula and compared to phytohormone effects. Ulvan induced a gene expression signature similar to that observed upon methyl jasmonate treatment (MeJA). Involvement of jasmonic acid (JA) in ulvan response was confirmed by detecting induction of protease inhibitory activity and by hormonal profiling of JA, salicylic acid (SA) and abscisic acid (ABA). Ulvan activity on the hormonal pathway was further consolidated by using Arabidopsis hormonal mutants. Altogether, our results demonstrate that green algae are a potential reservoir of ulvan elicitor which acts through the JA pathway. PMID:20445752

  9. Thermodynamic data for modeling acid mine drainage problems: compilation and estimation of data for selected soluble iron-sulfate minerals

    USGS Publications Warehouse

    Hemingway, Bruch S.; Seal, Robert R., II; Chou, I-Ming

    2002-01-01

    Enthalpy of formation, Gibbs energy of formation, and entropy values have been compiled from the literature for the hydrated ferrous sulfate minerals melanterite, rozenite, and szomolnokite, and a variety of other hydrated sulfate compounds. On the basis of this compilation, it appears that there is no evidence for an excess enthalpy of mixing for sulfate-H2O systems, except for the first H2O molecule of crystallization. The enthalpy and Gibbs energy of formation of each H2O molecule of crystallization, except the first, in the iron(II) sulfate - H2O system is -295.15 and -238.0 kJ?mol-1, respectively. The absence of an excess enthalpy of mixing is used as the basis for estimating thermodynamic values for a variety of ferrous, ferric, and mixed-valence sulfate salts of relevance to acid-mine drainage systems.

  10. Lack of acidic fibroblast growth factor activation by heparan sulfate species from diabetic rat skin.

    PubMed

    Bourin, M C

    1997-06-01

    The glucosaminoglycans isolated from the skin of control and streptozotocin-diabetic rats were fractionated on ion-exchange chromatography into a heparan sulfate (HS)-like and a heparin-like species. In addition, a low sulfated fraction was isolated from the diabetics. The HS and heparin-like fractions isolated from the diabetics (in contrast to the low sulfated fractions) retained high affinity for the acidic (FGF-1) and basic (FGF-2) fibroblast growth factors. In culture, the fractions purified from the control rats and the heparin-like material isolated from the diabetics mediated the biological activity of both FGFs in a dose-dependent manner. By contrast, the diabetic HS-like fractions promoted the biological activity of FGF-2 but not of FGF-1. The results support the idea that the structural motives in HS required for FGF-1 and FGF-2 mediated receptor signalling are different. They may be relevant to the impaired wound healing observed in the disease.

  11. Changes in water quality following tidal inundation of coastal lowland acid sulfate soil landscapes

    NASA Astrophysics Data System (ADS)

    Johnston, Scott G.; Bush, Richard T.; Sullivan, Leigh A.; Burton, Edward D.; Smith, Douglas; Martens, Michelle A.; McElnea, Angus E.; Ahern, R., , Col; Powell, Bernard; Stephens, Luisa P.; Wilbraham, Steve T.; van Heel, Simon

    2009-01-01

    This study examines the remediation of surface water quality in a severely degraded coastal acid sulfate soil landscape. The remediation strategy consisted of partial restoration of marine tidal exchange within estuarine creeks and incremental tidal inundation of acidified soils, plus strategic liming of drainage waters. Time-series water quality and climatic data collected over 5 years were analysed to assess changes in water quality due to this remediation strategy. A time-weighted rainfall function (TWR) was generated from daily rainfall data to integrate the effects of antecedent rainfall on shallow groundwater levels in a way that was relevant to acid export dynamics. Significant increases in mean pH were evident over time at multiple monitoring sites. Regression analysis at multiple sites revealed a temporal progression of change in significant relationships between mean daily electrical conductivity (EC) vs. mean daily pH, and TWR vs. mean daily pH. These data demonstrate a substantial decrease over time in the magnitude of creek acidification per given quantity of antecedent rainfall. Data also show considerable increase in soil pH (2-3 units) in formerly acidified areas subject to tidal inundation. This coincides with a decrease in soil pe, indicating stronger reducing conditions. These observations suggest a fundamental shift has occurred in sediment geochemistry in favour of proton-consuming reductive processes. Combined, these data highlight the potential effectiveness of marine tidal inundation as a landscape-scale acid sulfate soil remediation strategy.

  12. Groundwater or floodwater? Assessing the pathways of metal exports from a coastal acid sulfate soil catchment.

    PubMed

    Santos, Isaac R; de Weys, Jason; Eyre, Bradley D

    2011-11-15

    Daily observations of dissolved aluminum, iron, and manganese in an estuary downstream of a coastal acid sulfate soil (CASS) catchment provided insights into how floods and submarine groundwater discharge drive wetland metal exports. Extremely high Al, Fe, and Mn concentrations (up to 40, 374, and 8 mg L(-1), respectively) were found in shallow acidic groundwaters from the Tuckean Swamp, Australia. Significant correlations between radon (a natural groundwater tracer) and metals in surface waters revealed that metal loads were driven primarily by groundwater discharge. Dissolved Fe, Mn, and Al loads during a 16-day flood triggered by a 213 mm rain event were respectively 80, 35, and 14% of the total surface water exports during the four months of observations. Counter clockwise hysteresis was observed for Fe and Mn in surface waters during the flood due to delayed groundwater inputs. Groundwater-derived Fe fluxes into artificial drains were 1 order of magnitude higher than total surface water exports, which is consistent with the known accumulation of monosulfidic black ooze within the wetland drains. Upscaling the Tuckean catchment export estimates yielded dissolved Fe fluxes from global acid sulfate soil catchments on the same order of magnitude of global river inputs into estuaries.

  13. Ultrastructural localization of acid protein polysaccharides and calcium in the vacuoles of the chicken thrombocyte.

    PubMed

    Daimon, T; Uchida, K; Mizuhira, V

    1977-04-20

    The coexistence of acid protein polysaccharides and calcium in the vacuoles of chicken thrombocytes were studied by means of ultrahistochemical methods and electron probe X-ray microanalysis. The thrombocytes possessed large vacuoles of a surface connected membrane system. After both ruthenium red staining and tannic acid fixation the innersurface coat of vacuoles was always strongly and continously visualized. Electron microscopic X-ray microprobe analysis of antimonate precipitates in thrombocytes fixed in K-antimonate-OsO4 revealed calcium localization on the innersurface of vacuoles. From these facts it seems likely that the vacuoles of the surface connected membrane system may take part in the pool or the transport of calcium.

  14. Acid copper sulfate plating bath: Control of chloride and copper. Final report

    SciTech Connect

    Borhani, K.J.

    1992-08-01

    Plated-through holes in high-reliability printed wiring boards require a ductile copper plate of uniform consistency. The level of control of the chemical constituents in the electroplating solutions dictates the physical properties of the copper plate. To improve the control of the chemical bath constituents, in-situ methods for electrochemically determining copper and chloride in acid copper sulfate baths were developed. A solid-state ion-selective electrode was used for the chloride ion and proved to be more reproducible than conventional silver chloride turbidimetric methods. The use of a copper solid-state ion-selective electrode in-situ was also successful in this application.

  15. The electrochemical corrosion of bulk nanocrystalline ingot iron in acidic sulfate solution.

    PubMed

    Wang, S G; Shen, C B; Long, K; Zhang, T; Wang, F H; Zhang, Z D

    2006-01-12

    The corrosion properties of bulk nanocrystalline ingot iron (BNII) fabricated from conventional polycrystalline ingot iron (CPII) by severe rolling were investigated by means of immersion test, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS) tests, and scanning electron microscopy (SEM) observation. These experimental results indicate that BNII possesses excellent corrosion resistance in comparison with CPII in acidic sulfate solution at room temperature. It may mainly result from different surface microstructures between CPII and BNII. However, the corrosion resistance of nanocrystalline materials is usually degraded because of their metastable microstructure nature, and the residual stress in nanocrystalline materials also can result in degradation of corrosion resistance according to the traditional point of view.

  16. Aerosol pH buffering in the southeastern US: Fine particles remain highly acidic despite large reductions in sulfate

    NASA Astrophysics Data System (ADS)

    Weber, R. J.; Guo, H.; Russell, A. G.; Nenes, A.

    2015-12-01

    pH is a critical aerosol property that impacts many atmospheric processes, including biogenic secondary organic aerosol formation, gas-particle phase partitioning, and mineral dust or redox metal mobilization. Particle pH has also been linked to adverse health effects. Using a comprehensive data set from the Southern Oxidant and Aerosol Study (SOAS) as the basis for thermodynamic modeling, we have shown that particles are currently highly acidic in the southeastern US, with pH between 0 and 2. Sulfate and ammonium are the main acid-base components that determine particle pH in this region, however they have different sources and their concentrations are changing. Over 15 years of network data show that sulfur dioxide emission reductions have resulted in a roughly 70 percent decrease in sulfate, whereas ammonia emissions, mainly link to agricultural activities, have been largely steady, as have gas phase ammonia concentrations. This has led to the view that particles are becoming more neutralized. However, sensitivity analysis, based on thermodynamic modeling, to changing sulfate concentrations indicates that particles have remained highly acidic over the past decade, despite the large reductions in sulfate. Furthermore, anticipated continued reductions of sulfate and relatively constant ammonia emissions into the future will not significantly change particle pH until sulfate drops to clean continental background levels. The result reshapes our expectation of future particle pH and implies that atmospheric processes and adverse health effects linked to particle acidity will remain unchanged for some time into the future.

  17. Development of poly(aspartic acid-co-malic acid) composites for calcium carbonate and sulphate scale inhibition.

    PubMed

    Mithil Kumar, N; Gupta, Sanjay Kumar; Jagadeesh, Dani; Kanny, K; Bux, F

    2015-01-01

    Polyaspartic acid (PSI) is suitable for the inhibition of inorganic scale deposition. To enhance its scale inhibition efficiency, PSI was modified by reacting aspartic acid with malic acid (MA) using thermal polycondensation polymerization. This reaction resulted in poly(aspartic acid-co-malic acid) (PSI-co-MA) dual polymer. The structural, chemical and thermal properties of the dual polymers were analysed by using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and gel permeation chromatography. The effectiveness of six different molar ratios of PSI-co-MA dual polymer for calcium carbonate and calcium sulphate scale inhibition at laboratory scale batch experiments was evaluated with synthetic brine solution at selected doses of polymer at 65-70°C by the static scale test method. The performance of PSI-co-MA dual polymer for the inhibition of calcium carbonate and calcium sulphate precipitation was compared with that of a PSI single polymer. The PSI-co-MA exhibited excellent ability to control inorganic minerals, with approximately 85.36% calcium carbonate inhibition and 100% calcium sulphate inhibition at a level of 10 mg/L PSI-co-MA, respectively. Therefore, it may be reasonably concluded that PSI-co-MA is a highly effective scale inhibitor for cooling water treatment applications.

  18. Effect of L-lactic acid on calcium absorption in rats fed omeprazole.

    PubMed

    Chonan, O; Takahashi, R; Yasui, H; Watanuki, M

    1998-06-01

    We examined the effect of L-lactic acid on calcium absorption in male Wistar rats made achlorhydric by dietary omeprazole, a proton pump inhibitor. The dietary omeprazole intake (0.03 g/100 g of diet) increased the gastric pH and decreased the apparent calcium absorption ratio. Dietary famotidine (0.03 g/100 g of diet), an H2-receptor antagonist, and lower doses of omeprazole (0.005 or 0.01 g/100 g of diet) did not affect the gastric pH or the calcium absorption. In a second experiment, dietary lactic acid (0.5, 1.0, or 2.5 g/100 g of diet) increased the intestinal calcium absorption dose dependently in rats fed omeprazole (0.03 g/100 g of diet). The gastric pH was significantly decreased only in the rats fed higher doses of lactic acid (1.0, or 2.5 g/100 g of diet). In a third experiment, a dietary sour milk beverage containing lactic acid (0.5 g/100 g of diet) increased the intestinal calcium absorption, but did not affect the gastric pH in rats fed omeprazole (0.03 g/100 g of diet). Although the significance of gastric acid in terms of overall calcium absorption is not known, under the present experimental conditions, the inhibition of gastric acid secretion by dietary omeprazole decreased the apparent calcium absorption, and the dietary lactic acid prevented the calcium absorption in rats fed omeprazole.

  19. Thermodynamics of aqueous sodium sulfate from the temperatures 273 K to 373 K and mixtures of aqueous sodium sulfate and sulfuric acid at 298. 15 K

    SciTech Connect

    Hovey, J.K.; Pitzer, K.S. ); Rard, J.A. )

    1991-07-01

    New isopiestic vapor-pressure measurements on the aqueous system {l brace}(1{minus}y)H{sub 2}SO{sub 4}+yNA{sub 2}SO{sub 4}{r brace} along with earlier experimental investigations that span the range from y=0 to y=1 and infinitely dilute to supersaturated molalities have been analyzed in terms of the Pitzer ion-interaction model. Refined ion-interaction parameters for aqueous sodium sulfate valid over the temperature range 273 K to 373 K have been calculated and used for analyzing results for mixtures containing sulfuric acid and sodium sulfate at 298.15 K. Analysis of experimental results for these aqueous mixtures required explicit consideration of the dissociation reaction of bisulfate ion. Previous treatments of aqueous sulfuric acid and subsequently the bisulfate dissociation equilibrium valid in the range 273 K to 343 K were employed as a first approximation in representing the mixed solutions. Two sets of Pitzer ion-interaction parameters are presented for (sodium sulfate + sulfuric acid). The validity of the first set is limited in ionic strength and molality to saturated solutions of pure aqueous sodium sulfate (4 mol{center dot}kg{sup {minus}1}). The second set of parameters corresponds to a slightly less precise representation but is valid over the entire range of experimental results considered. Both sets of parameters provide a more complete description of pure sulfuric acid solutions because of the removal of various redundancies of ion-interaction parameters. The specific ion-interaction terms used and the overall fitting procedure are described as well as selected examples of relevant thermodynamic calculations in the mixed system Na{sub 2}SO{sub 4}-H{sub 2}SO{sub 4}-H{sub 2}O. 33 refs., 6 figs., 5 tabs.

  20. Thermodynamics of aqueous sodium sulfate from the temperatures 273 K to 373 K and mixtures of aqueous sodium sulfate and sulfuric acid at 298.15 K

    SciTech Connect

    Hovey, J.K.; Pitzer, K.S.; Rard, J.A.

    1991-07-01

    New isopiestic vapor-pressure measurements on the aqueous system {l_brace}(1{minus}y)H{sub 2}SO{sub 4}+yNA{sub 2}SO{sub 4}{r_brace} along with earlier experimental investigations that span the range from y=0 to y=1 and infinitely dilute to supersaturated molalities have been analyzed in terms of the Pitzer ion-interaction model. Refined ion-interaction parameters for aqueous sodium sulfate valid over the temperature range 273 K to 373 K have been calculated and used for analyzing results for mixtures containing sulfuric acid and sodium sulfate at 298.15 K. Analysis of experimental results for these aqueous mixtures required explicit consideration of the dissociation reaction of bisulfate ion. Previous treatments of aqueous sulfuric acid and subsequently the bisulfate dissociation equilibrium valid in the range 273 K to 343 K were employed as a first approximation in representing the mixed solutions. Two sets of Pitzer ion-interaction parameters are presented for (sodium sulfate + sulfuric acid). The validity of the first set is limited in ionic strength and molality to saturated solutions of pure aqueous sodium sulfate (4 mol{center_dot}kg{sup {minus}1}). The second set of parameters corresponds to a slightly less precise representation but is valid over the entire range of experimental results considered. Both sets of parameters provide a more complete description of pure sulfuric acid solutions because of the removal of various redundancies of ion-interaction parameters. The specific ion-interaction terms used and the overall fitting procedure are described as well as selected examples of relevant thermodynamic calculations in the mixed system Na{sub 2}SO{sub 4}-H{sub 2}SO{sub 4}-H{sub 2}O. 33 refs., 6 figs., 5 tabs.

  1. Calcium.

    PubMed

    Williams, Robert J P

    2002-01-01

    This chapter describes the chemical and biological value of the calcium ion. In calcium chemistry, our main interest is in equilibria within static, nonflowing systems. Hence, we examined the way calcium formed precipitates and complex ions in solution. We observed thereafter its uses by humankind in a vast number of materials such as minerals, e.g., marble, concrete, mortars, which parallel the biological use in shells and bones. In complex formation, we noted that many combinations were of anion interaction with calcium for example in the uses of detergents and medicines. The rates of exchange of calcium from bound states were noted but they had little application. Calcium ions do not act as catalysts of organic reactions. In biological systems, interest is in the above chemistry, but extends to the fact that Ca2+ ions can carry information by flowing in one solution or from one solution to another through membranes. Hence, we became interested in the details of rates of calcium exchange. The fast exchange of this divalent ion from most organic binding sites has allowed it to develop as the dominant second messenger. Now the flow can be examined in vitro as calcium binds particular isolated proteins, which it activates as seen in physical mechanical changes or chemical changes and this piece-by-piece study of cells is common. Here, however, we have chosen to stress the whole circuit of Ca2+ action indicating that the cell is organized both at a basal and an activated state kinetic level by the steady state flow of the ion (see Fig. 11). Different time constants of exchange utilizing very similar binding constants lead to: 1) fast responses as in the muscle of an animal; or 2) slower change as in differentiation of an egg or seed. Many other changes of state may relate to Ca2+ steady-state levels of flow in the circuitry and here we point to two: 1) dormancy in reptiles and animals; and 2) sporulation in both bacteria and lower plants. In the other chapters of

  2. Sulfur geochemistry of hydrothermal waters in Yellowstone National Park: IV Acid-sulfate waters

    USGS Publications Warehouse

    Kirk, Nordstrom D.; Blaine, McCleskey R.; Ball, J.W.

    2009-01-01

    Many waters sampled in Yellowstone National Park, both high-temperature (30-94 ??C) and low-temperature (0-30 ??C), are acid-sulfate type with pH values of 1-5. Sulfuric acid is the dominant component, especially as pH values decrease below 3, and it forms from the oxidation of elemental S whose origin is H2S in hot gases derived from boiling of hydrothermal waters at depth. Four determinations of pH were obtained: (1) field pH at field temperature, (2) laboratory pH at laboratory temperature, (3) pH based on acidity titration, and (4) pH based on charge imbalance (at both laboratory and field temperatures). Laboratory pH, charge imbalance pH (at laboratory temperature), and acidity pH were in close agreement for pH ??10%, a selection process was used to compare acidity, laboratory, and charge balance pH to arrive at the best estimate. Differences between laboratory and field pH can be explained based on Fe oxidation, H2S or S2O3 oxidation, CO2 degassing, and the temperature-dependence of pK2 for H2SO4. Charge imbalances are shown to be dependent on a speciation model for pH values 350 mg/L Cl) decrease as the Cl- concentration increases from boiling which appears inconsistent with the hypothesis of H2S oxidation as a source of hydrothermal SO4. This trend is consistent with the alternate hypothesis of anhydrite solubility equilibrium. Acid-sulfate water analyses are occasionally high in As, Hg, and NH3 concentrations but in contrast to acid mine waters they are low to below detection in Cu, Zn, Cd, and Pb concentrations. Even concentrations of SO4, Fe, and Al are much lower in thermal waters than acid mine waters of the same pH. This difference in water chemistry may explain why certain species of fly larvae live comfortably in Yellowstone's acid waters but have not been observed in acid rock drainage of the same pH.

  3. Carbonic acid: an important intermediate in the surface chemistry of calcium carbonate.

    PubMed

    Al-Hosney, Hashim A; Grassian, Vicki H

    2004-07-01

    Calcium carbonate is an important and ubiquitous component of biological and geochemical systems. In this study, the surface chemistry of calcium carbonate with several trace atmospheric gases including HNO3, SO2, HCOOH, and CH3COOH is investigated with infrared spectroscopy. Adsorbed carbonic acid, H2CO3, is found to be an intermediate in these reactions. In the absence of adsorbed water, carbonic acid is stable on the surface at room temperature. However, upon water adsorption, carbonic acid dissociates as indicated by the evolution of gaseous CO2 and the disappearance of infrared absorption bands associated with adsorbed carbonic acid. Thus, it is postulated that under ambient conditions, carbonic acid may be an important albeit short-lived intermediate in the surface chemistry of calcium carbonate. PMID:15225019

  4. Severe leaching of calcium ions from fir needles caused by acid fog.

    PubMed

    Igawa, Manabu; Kase, Toshiyuki; Satake, Kosuke; Okochi, Hiroshi

    2002-01-01

    We have measured the components of the throughfall under fir trees (Abies firma) in the field around Mt. Oyama, where the forest appears to be declining, for the period 1994-1998. Exposure experiments of a simulated acid fog to fir twigs were performed under field conditions. There was a similarity between the acid response in the field and that in the laboratory. In both studies, the severe leaching of calcium ions from the needle surface was caused by exposure to acid fog. We also applied acid fog to fir seedlings over 1 year and observed a decrease in the growth of the seedlings due to this application in the dormant season. These results suggest that the severe leaching of calcium ions due to acid fog may cause the deficiency of calcium and be responsible for the decline of the fir trees.

  5. ADVANCES IN BIOTREATMENT OF ACID MINE DRAINAGE AND BIORECOVERY OF METALS: 2. MEMBRANE BIOREACTOR SYSTEM FOR SULFATE REDUCTION

    EPA Science Inventory

    Acid-mine drainage (AMD) is a severe pollution problem attributed to past mining activities. AMD is an acidic, metal-bearing wastewater generated by the oxidation of metal sulfides to sulfates by Thiobacillus bacteria in both the active and abandoned mining operations. The wastew...

  6. BASE COMPOSITION OF THE DEOXYRIBONUCLEIC ACID OF SULFATE-REDUCING BACTERIA

    PubMed Central

    Sigal, Nicole; Senez, Jacques C.; Le Gall, Jean; Sebald, Madeleine

    1963-01-01

    Sigal, Nicole (Laboratoire de Chimie Bactérienne du CNRS, Marseille, France), Jacques C. Senez, Jean Le Gall, and Madeleine Sebald. Base composition of the deoxyribonucleic acid of sulfate-reducing bacteria. J. Bacteriol. 85:1315–1318. 1963—The deoxyribonucleic acid constitution of several strains of sulfate-reducing bacteria has been analytically determined. The results of these studies show that this group of microorganisms includes at least four subgroups characterized by significantly different values of the adenine plus thymine to guanine plus cytosine ratio. The nonsporulated forms with polar flagellation, containing both cytochrome c3 and desulfoviridin, are divided into two subgroups. One includes the fresh-water, nonhalophilic strains with base ratio from 0.54 to 0.59, and the other includes the halophilic or halotolerant strains with base ratio from 0.74 to 0.77. The sporulated, peritrichous strains without cytochrome and desulfoviridin (“nigrificans” and “orientis”) are distinct from the above two types and differ from each other, having base ratios of 1.20 and 1.43, respectively. PMID:14047223

  7. Iron Absorption from Two Milk Formulas Fortified with Iron Sulfate Stabilized with Maltodextrin and Citric Acid

    PubMed Central

    Pizarro, Fernando; Olivares, Manuel; Maciero, Eugenia; Krasnoff, Gustavo; Cócaro, Nicolas; Gaitan, Diego

    2015-01-01

    Background: Fortification of milk formulas with iron is a strategy widely used, but the absorption of non-heme iron is low. The purpose of this study was to measure the bioavailability of two iron fortified milk formulas designed to cover toddlers’ nutritional needs. These milks were fortified with iron sulfate stabilized with maltodextrin and citric acid. Methods: 15 women (33–47 years old) participated in study. They received on different days, after an overnight fast, 200 mL of Formula A; 200 mL of Formula B; 30 mL of a solution of iron and ascorbic acid as reference dose and 200 mL of full fat cow’s milk fortified with iron as ferrous sulfate. Milk formulas and reference dose were labeled with radioisotopes 59Fe or 55Fe, and the absorption of iron measured by erythrocyte incorporation of radioactive Fe. Results: The geometric mean iron absorption corrected to 40% of the reference dose was 20.6% for Formula A and 20.7% for Formula B, versus 7.5% of iron fortified cow’s milk (p < 0.001). The post hoc Sheffé indeed differences between the milk formulas and the cow’s milk (p < 0.001). Conclusion: Formulas A and B contain highly bioavailable iron, which contributes to covering toddlers’ requirements of this micronutrient. PMID:26529007

  8. Morphologies, mechanical properties and thermal stability of poly(lactic acid) toughened by precipitated barium sulfate

    NASA Astrophysics Data System (ADS)

    Yang, Jinian; Wang, Chuang; Shao, Kaiyun; Ding, Guoxin; Tao, Yulun; Zhu, Jinbo

    2015-11-01

    Poly(lactic acid) (PLA)-based composites were prepared by blending PLA with precipitated barium sulfate (BaSO4) modified with stearic acid. The morphologies, mechanical properties and thermal stability of samples with increased mass fraction of BaSO4 were investigated. Results showed that PLA was toughened and reinforced simultaneously by incorporation of precipitated BaSO4 particles. The highest impact toughness and elongation at break were both achieved at 15% BaSO4, while the elastic modulus increased monotonically with increasing BaSO4 loading. Little effect of BaSO4 on the thermal behavior of PLA was observed in the present case. However, the thermal stability of PLA/BaSO4 composites at high temperature was enhanced.

  9. Effect of pH on the Preparation of {alpha}-Calcium Sulfate Hemihydrate from FGD Gypsum with the Hydrothermal Method

    SciTech Connect

    Guan, B.H.; Shen, Z.X.; Wu, Z.B.; Yang, L.C.; Ma, X.F.

    2008-12-15

    pH is one of the most important parameters that determine the crystallization process, but it is always neglected in the preparation of {alpha}-calcium sulfate hemihydrate ({alpha}-HH) from calcium sulfate dihydrate (DH) with the hydrothermal method. Flue gas desulfurization (FGD) gypsum, which is mainly composed of DH, was used as raw material to obtain {alpha}-HH through dehydration in a Ca-Mg-K-Cl-solution medium at 95{sup o}C under atmospheric pressure. The initial pH values of the suspensions were adjusted from 1.2 to 8.0 to explore the influence of pH on the dehydration process and the product characteristics. The results showed that {alpha}-HH crystal was the only dehydration product with the pH ranging from 1.2 to 8.0. With the increase of initial pH, the dehydration rate decreased and the formed {alpha}-HH crystal had a larger particle size. The length/width ratio decreased markedly from 4.8 to 2.9 as the initial pH increased from 1.2 to 7.3. pH had a profound influence on the dehydration of DH and the morphology of alpha-HH via its effect on the supersaturation and perhaps also the precipitation of Ca(OH){sub 2} in an alkaline environment.

  10. [Effect of calcium on medium alkalinization induced by salicylic acid in Salvia miltiorrhiza suspension cultures].

    PubMed

    Liu, Liancheng; Wang, Cong; Dong, Juan'e; Su, Hui; Zhuo, Zequn; Xue, Yaxin

    2013-07-01

    We studied medium alkalinization in Salvia miltiorrhiza suspension cultures treated with salicylic acid and the effect of Ca2+ in this process through application of calcium channel antagonists (Verapamil, LaCl3, LiCl, 2-APB) and ionophore A23187. The results show that salicylic acid could induce significant medium alkalinization in S. miltiorrhiza culture. Verapamil and LaCl3 or LiCl and 2-APB, two different groups of calcium channel antagonist, significantly inhibited the medium alkalinization induced by salicylic acid. However, the suppression effect of verapamil or LaCl3 on medium alkalinization induced by salicylic acid was higher than that of LiCl or 2-APB. When two types of calcium channel inhibitor (LaCl3 and 2-APB) were used together, the medium alkalinization induced by salicylic acid was completely suppressed and even reduced the pH in medium. On the other hand, A23187 could promote the medium alkalinization. Based on the results above, we speculated that salicylic acid could induce significant medium alkalinization in S. miltiorrhiza culture, depending on the calcium from both extracell and intracell. Moreover, calcium from extracell plays a more dominant role in this process. Reveal of relationship in this research between Ca2+ and medium alkalinization can provide theory evidence for mechanism of the plant secondary metabolism.

  11. Distribution of iron- and sulfate-reducing bacteria across a coastal acid sulfate soil (CASS) environment: implications for passive bioremediation by tidal inundation

    PubMed Central

    Ling, Yu-Chen; Bush, Richard; Grice, Kliti; Tulipani, Svenja; Berwick, Lyndon; Moreau, John W.

    2015-01-01

    Coastal acid sulfate soils (CASS) constitute a serious and global environmental problem. Oxidation of iron sulfide minerals exposed to air generates sulfuric acid with consequently negative impacts on coastal and estuarine ecosystems. Tidal inundation represents one current treatment strategy for CASS, with the aim of neutralizing acidity by triggering microbial iron- and sulfate-reduction and inducing the precipitation of iron-sulfides. Although well-known functional guilds of bacteria drive these processes, their distributions within CASS environments, as well as their relationships to tidal cycling and the availability of nutrients and electron acceptors, are poorly understood. These factors will determine the long-term efficacy of “passive” CASS remediation strategies. Here we studied microbial community structure and functional guild distribution in sediment cores obtained from 10 depths ranging from 0 to 20 cm in three sites located in the supra-, inter- and sub-tidal segments, respectively, of a CASS-affected salt marsh (East Trinity, Cairns, Australia). Whole community 16S rRNA gene diversity within each site was assessed by 454 pyrotag sequencing and bioinformatic analyses in the context of local hydrological, geochemical, and lithological factors. The results illustrate spatial overlap, or close association, of iron-, and sulfate-reducing bacteria (SRB) in an environment rich in organic matter and controlled by parameters such as acidity, redox potential, degree of water saturation, and mineralization. The observed spatial distribution implies the need for empirical understanding of the timing, relative to tidal cycling, of various terminal electron-accepting processes that control acid generation and biogeochemical iron and sulfur cycling. PMID:26191042

  12. Distribution of iron- and sulfate-reducing bacteria across a coastal acid sulfate soil (CASS) environment: implications for passive bioremediation by tidal inundation.

    PubMed

    Ling, Yu-Chen; Bush, Richard; Grice, Kliti; Tulipani, Svenja; Berwick, Lyndon; Moreau, John W

    2015-01-01

    Coastal acid sulfate soils (CASS) constitute a serious and global environmental problem. Oxidation of iron sulfide minerals exposed to air generates sulfuric acid with consequently negative impacts on coastal and estuarine ecosystems. Tidal inundation represents one current treatment strategy for CASS, with the aim of neutralizing acidity by triggering microbial iron- and sulfate-reduction and inducing the precipitation of iron-sulfides. Although well-known functional guilds of bacteria drive these processes, their distributions within CASS environments, as well as their relationships to tidal cycling and the availability of nutrients and electron acceptors, are poorly understood. These factors will determine the long-term efficacy of "passive" CASS remediation strategies. Here we studied microbial community structure and functional guild distribution in sediment cores obtained from 10 depths ranging from 0 to 20 cm in three sites located in the supra-, inter- and sub-tidal segments, respectively, of a CASS-affected salt marsh (East Trinity, Cairns, Australia). Whole community 16S rRNA gene diversity within each site was assessed by 454 pyrotag sequencing and bioinformatic analyses in the context of local hydrological, geochemical, and lithological factors. The results illustrate spatial overlap, or close association, of iron-, and sulfate-reducing bacteria (SRB) in an environment rich in organic matter and controlled by parameters such as acidity, redox potential, degree of water saturation, and mineralization. The observed spatial distribution implies the need for empirical understanding of the timing, relative to tidal cycling, of various terminal electron-accepting processes that control acid generation and biogeochemical iron and sulfur cycling. PMID:26191042

  13. Distribution of iron- and sulfate-reducing bacteria across a coastal acid sulfate soil (CASS) environment: implications for passive bioremediation by tidal inundation.

    PubMed

    Ling, Yu-Chen; Bush, Richard; Grice, Kliti; Tulipani, Svenja; Berwick, Lyndon; Moreau, John W

    2015-01-01

    Coastal acid sulfate soils (CASS) constitute a serious and global environmental problem. Oxidation of iron sulfide minerals exposed to air generates sulfuric acid with consequently negative impacts on coastal and estuarine ecosystems. Tidal inundation represents one current treatment strategy for CASS, with the aim of neutralizing acidity by triggering microbial iron- and sulfate-reduction and inducing the precipitation of iron-sulfides. Although well-known functional guilds of bacteria drive these processes, their distributions within CASS environments, as well as their relationships to tidal cycling and the availability of nutrients and electron acceptors, are poorly understood. These factors will determine the long-term efficacy of "passive" CASS remediation strategies. Here we studied microbial community structure and functional guild distribution in sediment cores obtained from 10 depths ranging from 0 to 20 cm in three sites located in the supra-, inter- and sub-tidal segments, respectively, of a CASS-affected salt marsh (East Trinity, Cairns, Australia). Whole community 16S rRNA gene diversity within each site was assessed by 454 pyrotag sequencing and bioinformatic analyses in the context of local hydrological, geochemical, and lithological factors. The results illustrate spatial overlap, or close association, of iron-, and sulfate-reducing bacteria (SRB) in an environment rich in organic matter and controlled by parameters such as acidity, redox potential, degree of water saturation, and mineralization. The observed spatial distribution implies the need for empirical understanding of the timing, relative to tidal cycling, of various terminal electron-accepting processes that control acid generation and biogeochemical iron and sulfur cycling.

  14. Effect of fertilizer on the growth of radish plants exposed to simulated acidic rain containing different sulfate to nitrate ratios.

    PubMed

    Jacobson, J S; Troiano, J J; Heller, L I; Osmeloski, L

    1987-01-01

    Two successive experiments were performed in the greenhouse to test the hypothesis that plant response to the amounts and ratios of sulfuric and nitric acids in rain is affected by the amount of fertilizer added to the growing medium. Radish plants, grown with different levels of N?P?K fertilizer, were given ten 1-h exposures over a 3-week period to simulate acidic rain at pH values from 2.6 to 5.0 and sulfate to nitrate mass ratios from 0.3 to 7.5. Increased acidity of simulated rain reduced plant growth, with a greater depression of hypocotyl mass than shoot mass. The reverse growth response occurred with increased supply of fertilizer: plant biomass rose with a larger increase in shoot mass than hypocotyl mass. In one experiment, plants that received a greater supply of fertilizer exhibited more obvious reductions in growth of hoots at the higher levels of acidity of simulated rain. There were no significant effects of sulfate to nitrate ratios in simulated rain on plant growth, nor any effect of this ratio on the response of shoots and hypocotyls to acidity of simulated rain. Addition of fertilizer had no effect on plant response to sulfate to nitrate ratios. These results do not support the hypothesis that nutrient-deficient plants are either more or less responsive to sulfate and nitrate in rain than plants grown with optimal supplies of nutrients. They support previous results indicating no effects of sulfate to nitrate ratio in simulated acidic rain on plant growth. The results also suggest that the greatest risk of harmful effects on vegetation may come from the combination of high sulfate and high acidity in rainfall.

  15. Solid/liquid phase diagram of the ammonium sulfate/glutaric acid/water system.

    PubMed

    Beyer, Keith D; Pearson, Christian S; Henningfield, Drew S

    2013-05-01

    We have studied the low temperature phase diagram and water activities of the ammonium sulfate/glutaric acid/water system using differential scanning calorimetry, infrared spectroscopy of thin films, and a new technique: differential scanning calorimetry-video microscopy. Using these techniques, we have determined that there is a temperature-dependent kinetic effect to the dissolution of glutaric acid in aqueous solution. We have mapped the solid/liquid ternary phase diagram, determined the water activities based on the freezing point depression, and determined the ice/glutaric acid phase boundary as well as the ternary eutectic composition and temperature. We have also modified our glutaric acid/water binary phase diagram previously published based on these new results. We compare our results for the ternary system to the predictions of the Extended AIM Aerosol Thermodynamics Model (E-AIM), and find good agreement for the ice melting points in the ice primary phase field of this system; however, significant differences were found with respect to phase boundaries, concentration and temperature of the ternary eutectic, and glutaric acid dissolution. PMID:23544733

  16. Arachidonic acid stimulates /sup 45/calcium efflux and HPL release in isolated trophoblast cells

    SciTech Connect

    Zeitler, P.; Murphy, E.; Handwerger, S.

    1986-01-13

    Previous investigations from this laboratory have indicated that arachidonic acid stimulates a rapid, dose-dependent and reversible increase in hPL release which is not dependent on cyclooxygenase or lipoxygenase metabolism. To investigate further the mechanism by which arachidonic acid stimulates the release of hPL, the effect of arachidonic acid on the release of /sup 45/Ca from perifused cells prelabelled with /sup 45/Ca was examined in an enriched cell culture population of term human syncytiotrophoblast. Arachidonic acid (10-100 ..mu..M) stimulated a dose-dependent, rapid, and reversible increase in the release of both /sup 45/Ca and hPL from the perifused placental cells. On the other hand, palmitic acid had little effect on either hPL release or /sup 45/Ca release even at concentrations as high as 100 ..mu..M. Ionophore A23187 (1-10..mu..M) also stimulated a dose-dependent and reversible increase in hPL release. Since arachidonic acid increases the mobilization of cellular calcium, as reflected by the increased /sup 45/calcium efflux, and since an increase in the intracellular calcium concentration appears to stimulate an increase in hPL release, these results suggest that the stimulation of hPL release by arachidonic acid may be due, at least in part, to the effects of the fatty acid on cellular calcium mobilization. 26 references, 5 figures.

  17. BENCH-SCALE EVALUATION OF CALCIUM SORBENTS FOR ACID GAS EMISSION CONTROL

    EPA Science Inventory

    Calcium sorbents for acid gas emission control were evaluated for effectiveness in removing SO2/HCl and SO2/NO from simulated incinerator and boiler flue gases. All tests were conducted in a bench-scale reactor (fixed-bed) simulating fabric filter conditions in an acid gas remova...

  18. Thermochemical Reduction Experiments of Native Sulfur, Sulfite, and Sulfate by Amino Acids at 150 - 200°C

    NASA Astrophysics Data System (ADS)

    Naraoka, H.; Watanabe, Y.; Ohmoto, H.

    2006-12-01

    We have conducted series of laboratory experiments to investigate geochemical characteristics (e.g., kinetics and sulfur isotope fractionations) of redox reactions between a variety of amino acids (alanine, glycine, hystidine, etc.) and native sulfur, sodium sulfite or sodium sulfate at 150 - 200°C. While previous researchers failed to demonstrate thermochemical sulfate reduction (TSR) at temperatures below 230°C using a variety of organic compounds (sugars, methane, xylene, etc), in our series of experiments, all S-species were reduced to H2S by amino acids without presence of initial H2S and at neutral pH (i.e., pH = 6) even at 150°C. The reduction rates generally decreased: (a) from native sulfur, to sulfite, and to sulfate; (b) from simple amino acids to more complex amino acids, particularly with aromatic functional groups (e.g., histidine); and (c) with decreasing temperatures. The rates of sulfite and S0 reduction were, respectively, approximately 2 and 3 orders of magnitude faster than those of sulfate. The kinetic isotope effects (Δ34S = δ34SH2S - δ34Sreactant) generally increased with increasing valence of the starting S-compounds. However, they have very complex trends for particularly experiments using sulfate. They fluctuated between positive and negative in others, and continued to increase or decrease in some runs up to +10 or -10 per mil. These variations likely associated with changes in S/C ratios of initial mixtures, and probably occurred because the generation of reductants (i.e., CH4, H2, and NH4+) from the solid mixtures varied; the kinetic isotope effects associated with sulfate reduction by NH4+ may be quite different from those associated with reduction by H2 and/or CH4. The Δ^{33}S values of run products (H2S) generally increased from +0.16 per mil to +0.61 per mil with decreasing rates of sulfate reduction.

  19. Role of basic amino acids in the interaction of bindin with sulfated fucans.

    PubMed

    DeAngelis, P L; Glabe, C G

    1988-10-18

    Bindin, the acrosomal sperm adhesion protein of the sea urchin Strongylocentrotus purpuratus, binds specifically and with high affinity (Kd = 10(-8) M) to egg sulfated fucans in the high ionic strength milieu of seawater (0.55 M salt). Previous studies indicated that the negatively charged sulfate groups of the polysaccharide are critical for binding which suggested a binding mechanism involving basic residues of bindin. We found that the binding of fucan to bindin or polyarginine is stable at the ionic strength of seawater, whereas the binding of fucan to polylysine or polyhistidine is inhibited by 50% or more at this ionic strength. Group-specific modification of either arginine, lysine, or histidine residues of bindin results in a substantial inactivation of fucan binding activity. Preincubation of bindin with fucan can almost completely protect bindin from inactivation by arginine-specific reagents, butanedione and phenylglyoxal, but only moderately slowed the inactivation by the histidine reagent diethyl pyrocarbonate. In contrast, prior fucan binding could not prevent loss of activity by the reaction of citraconic anhydride with lysine residues. Other sulfated polysaccharides which do not interact strongly with bindin did not protect binding from phenylglyoxal-mediated inactivation when 800-3000-fold more polysaccharide than fucan was used during the preincubation before modification. We found that the larger and more hydrophobic arginine-modifying reagents, camphorquinone-10-sulfonic acid and cyclohexanedione, fail to inactivate fucan binding, suggesting that essential arginine residues may reside in an environment with restricted accessibility to these reagents. Parallel kinetic studies monitoring [14C]phenylglyoxal incorporation and fucan binding inactivation indicate that several of the four total arginine residues may be critical for fucan binding.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Short-term endproducts of sulfate reduction in a salt marsh: Formation of acid volatile sulfides, elemental sulfur, and pyrite

    NASA Astrophysics Data System (ADS)

    King, Gary M.; Howes, B. L.; Dacey, J. W. H.

    1985-07-01

    Rates of sulfate reduction, oxygen uptake and carbon dioxide production in sediments from a short Spartina alterniflora zone of Great Sippewissett Marsh were measured simultaneously during late summer. Surface sediments (0-2 cm) were dominated by aerobic metabolism which accounted for about 45% of the total carbon dioxide production over 0-15 cm. Rates of sulfate reduction agreed well with rates of total carbon dioxide production below 2 cm depth indicating that sulfate reduction was the primary pathway for sub-surface carbon metabolism. Sulfate reduction rates were determined using a radiotracer technique coupled with a chromous chloride digestion and carbon disulfide extraction of the sediment to determine the extent of formation of radiolabelled elemental sulfur and pyrite during shortterm (48 hr) incubations. In the surface 10 cm of the marsh sediments investigated, about 50% of the reduced radiosulfur was recovered as dissolved or acid volatile sulfides, 37% as carbon disulfide extractable sulfur, and only about 13% was recovered in a fraction operationally defined as pyrite. Correlations between the extent of sulfate depletion in the marsh sediments and the concentrations of dissolved and acid volatile sulfides supported the results of the radiotracer work. Our data suggest that sulfides and elemental sulfur may be major short-term end-products of sulfate reduction in salt marshes.

  1. Evidence for Acid-Sulfate Alteration in the Pahrump Hills Region, Gale Crater, Mars

    NASA Astrophysics Data System (ADS)

    Rampe, E. B.; Ming, D. W.; Vaniman, D. T.; Blake, D. F.; Chipera, S.; Morris, R. V.; Bish, D. L.; Cavanagh, P.; Achilles, C.; Bristow, T.; Fairen, A.; Morrison, S. M.; Treiman, A. H.; Crisp, J. A.; Downs, R. T.; Farmer, J. D.; Fendrich, K.; Morookian, J.

    2015-12-01

    The Pahrump Hills region of Gale crater is a ~12 m thick section of sedimentary rock in the Murray formation, interpreted as the basal geological unit of Mount Sharp. The Mars Science Laboratory, Curiosity, arrived at the Pahrump Hills in September 2014 and performed a detailed six-month investigation of the sedimentary structures, geochemistry, and mineralogy of the area. During the campaign, Curiosity drilled and delivered three mudstone samples (targets Confidence Hills, Mojave 2, and Telegraph Peak) to its internal instruments, including the CheMin XRD/XRF. Results from CheMin show that these samples have variable amounts of plagioclase, pyroxene, iron oxides, jarosite, phyllosilicates, cristobalite, and X-ray amorphous material. The presence of jarosite in all samples indicates these rocks were affected by acid-sulfate alteration, and the mineralogical and geochemical trends observed through the section may give more insight into this process. Geochemical data measured by APXS show enrichment in Si and depletion in Mg moving up section. CheMin data show that cristobalite is more abundant up section, whereas pyroxene and phyllosilicates are more abundant at the bottom of the section. Based on mineralogical and geochemical trends and diagenetic features observed in the Pahrump Hills, we hypothesize that the sediments were altered in-situ by acid-sulfate fluids moving down from the top of the section to leach mobile elements, dissolve the minerals most susceptible to acidic alteration, and precipitate secondary silica at the top of the section. Alternative interpretations of the observed mineralogical and geochemical data are possible, including the hypothesis that the redox conditions of the body of water in which the sediments were deposited changed over time.

  2. Microwave-assisted digestion using nitric acid for heavy metals and sulfated ash testing in active pharmaceutical ingredients.

    PubMed

    Pluhácek, T; Hanzal, J; Hendrych, J; Milde, D

    2016-04-01

    The monitoring of inorganic impurities in active pharmaceutical ingredients plays a crucial role in the quality control of the pharmaceutical production. The heavy metals and residue on ignition/sulfated ash methods employing microwave-assisted digestion with concentrated nitric acid have been demonstrated as alternatives to inappropriate compendial methods recommended in United States Pharmacopoeia (USP) and European Pharmacopoeia (Ph. Eur.). The recoveries using the heavy metals method ranged between 89% and 122% for nearly all USP and Ph. Eur. restricted elements as well as the recoveries of sodium sulfate spikes were around 100% in all tested matrices. The proposed microwave-assisted digestion method allowed simultaneous decomposition of 15 different active pharmaceutical ingredients with sample weigh up to 1 g. The heavy metals and sulfated ash procedures were successfully applied to the determination of heavy metals and residue on ignition/sulfated ash content in mycophenolate mofetil, nicergoline and silymarin. PMID:27209695

  3. Modeling the crystal distribution of lead-sulfate in lead-acid batteries with 3D spatial resolution

    NASA Astrophysics Data System (ADS)

    Huck, Moritz; Badeda, Julia; Sauer, Dirk Uwe

    2015-04-01

    For the reliability of lead-acid batteries it is important to have an accurate prediction of its response to load profiles. A model for the lead-sulfate growth is presented, which is embedded in a physical-chemical model with 3D spatial resolution is presented which is used for analyzing the different mechanism influencing the cell response. One import factor is the chemical dissolution and precipitation of lead-sulfate, since its dissolution speed limits the charging reaction and the accumulation of indissolvable of lead-sulfate leads to capacity degradation. The cell performance/behavior is not only determined by the amount of the sulfate but also by the radii and distribution of the crystals. The presented model can be used to for an improved understanding of the interaction of the different mechanisms.

  4. [Study on solid dispersion of precipitated calcium carbonate-based oleanolic acid].

    PubMed

    Yan, Hong-mei; Zhang, Zhen-hai; Jia, Xiao-bin; Jiang, Yan-rong; Sun, E

    2015-05-01

    Oleanolic acid-precipitated calcium carbonate solid dispersion was prepared by using solvent evaporation method. The microscopic structure and physicochemical properties of solid dispersion were analyzed using differential scanning calorimetry and scanning electron microscopy (SEM). And its in vitro release also was investigated. The properties of the precipitated calcium carbonate was studied which was as a carrier of oleanolic acid solid dispersion. Differential scanning calorimetry analysis suggested that oleanolic acid may be present in solid dispersion as amorphous substance. The in vitro release determination results of oleanolic acid-precipitated calcium carbonate (1: 5) solid dispersion showed accumulated dissolution rate of.oleanolic acid was up to 90% at 45 min. Accelerating experiment showed that content and in vitro dissolution of oleanolic acid solid dispersion did not change after storing over 6 months. The results indicated that in vitro dissolution of oleanolic acid was improved greatly by the solid dispersion with precipitated calcium carbonate as a carrier. The solid dispersion is a stabilizing system which has actual applied value.

  5. Effect of hydrochloric acid on sound absorption and relaxation frequency in magnesium sulfate solutions

    NASA Astrophysics Data System (ADS)

    Fisher, F. H.

    2002-05-01

    The epic work of Kurtze and Tamm on sound absorption spectroscopy in divalent sulfate electrolyte solutions (1953) from the low-kHz region up to over 200 MHz revealed astonishing variability at frequencies below 10 MHz and a common relaxation frequency at about 200 MHz. For magnesium sulfate [Epsom salts] solutions, the salt producing 30× the absorption of fresh water below the 100-kHz region in the oceans at low concentrations [~0.02 moles/liter], Kurtze and Tamm investigated the effects of adding HC1 or H2SO4. They found that as formal pH increased, the results were different for these acids in reducing the sound absorption. Fisher (1983) found that if the absorption was plotted against free hydrogen, ion concentration was the same. We used the 100-liter titanium sphere, a spare ballast tank from the WHOI submarine ALVIN. With precise temperature control, we found an increase in the relaxation frequency as HC1 was added in conjunction with the reduction in sound absorption. The results will be presented and an explanation will be proposed in the context of the Eigen and Tamm multistate dissociation model for MgSO4 (1962) which explains the effects of pressure on both absorption and conductance. [Work supported by ONR.] The author acknowledges C. C. Hsu for his work on this project.

  6. Folic Acid Linked Chondroitin Sulfate-Polyethyleneimine Copolymer Based Gene Delivery System.

    PubMed

    Lo, Yu-Lun; Lo, Pei-Chi; Chiu, Chien-Chih; Wang, Li-Fang

    2015-08-01

    In our previous study, chondroitin sulfate-polyethylenimine copolymers (CP) have been synthesized and confirmed as potential gene delivery vectors. Efficient gene transfection is realized by chondroitin sulfate (ChS) that promotes CD44- mediated endocytosis and enhances the cellular uptake of CP/pDNA polyplexes besides clathrin-mediated endocytosis. In this study, the CP was functionalized with a folic acid (FA) molecule. This ancillary ligand allows polyplexes to bind with folate receptors (FR) in addition to the CD44 receptor. We conjugated FA-linked polyethylene glycol (FA-PEG) onto CP (FPCP) for tumor targeting and also synthesized mPEG-CP (MPCP) for comparison. The in vitro cell tests of polymer/pDNA polyplexes were done in FR-expressed U87 and FR-deficient A549 cells. The polymers exhibited less cytotoxicity than PEI-10K as well as PEI-25K against U87 and A549 cells. The transfection efficiency of FPCP/pDNA was higher than those of MPCP/pDNA and CP/pDNA. The cellular uptake pathways of FPCP/pDNA were tested in the cells in the presence of different endocytic chemical inhibitors. The CD44-, folate-, and caveolae-mediated pathways are involved in internalization of FPCP/pDNA. Recognition of FPCP to those receptors on the tumor surface is beneficial for enhanced cellular uptake of FPCP/pDNA, resulting in higher transgene expression than CP/pDNA and MPCP/pDNA.

  7. [Rice straw and sewage sludge as carbon sources for sulfate-reducing bacteria treating acid mine drainage].

    PubMed

    Su, Yu; Wang, Jin; Peng, Shu-chuan; Yue, Zheng-bo; Chen, Tian-hu; Jin, Jie

    2010-08-01

    The performance of three organic carbon sources was assessed in terms of sulfate reduction and main metal removal, by using sewage sludge as the source of sulfate-reducing bacteria (SRB) and adding rice straw and ethanol with equal quantity. Results indicated that sewage sludge which contained certain amount of alkaline material could neutralize acidity of acid mine drainage(AMD) on the first day of experiment, elevating pH value from the initial 2.5 to around 5.4-6.3 and achieving suitable pH condition for SRB growth. Sewage sludge contained fewer biodegradable organic substance, reactive mixture with single sewage sludge showed the lowest sulfate reduction (65.9%). When the single sewage sludge was supplemented with rice straw, SRB reducing sulfate was enhanced (79.2%), because the degradation rate of rice straw was accelerated by the specific bacteria in sewage sludge, providing relatively abundant carbon source for SRB. Control experiment with ethanol was most effective in promoting sulfate reduction (97.9%). Metal removal efficiency in all three reactors was as high as 99% for copper, early copper removal was mainly attributed to the adsorption capacity of sewage sludge prior to SRB acclimation. It is feasible for using rice straw and sewage sludge as carbon sources for SRB treating acid mine drainage at a low cost, this may have significant implication for in situ bioremediation of mine environment.

  8. [Rice straw and sewage sludge as carbon sources for sulfate-reducing bacteria treating acid mine drainage].

    PubMed

    Su, Yu; Wang, Jin; Peng, Shu-chuan; Yue, Zheng-bo; Chen, Tian-hu; Jin, Jie

    2010-08-01

    The performance of three organic carbon sources was assessed in terms of sulfate reduction and main metal removal, by using sewage sludge as the source of sulfate-reducing bacteria (SRB) and adding rice straw and ethanol with equal quantity. Results indicated that sewage sludge which contained certain amount of alkaline material could neutralize acidity of acid mine drainage(AMD) on the first day of experiment, elevating pH value from the initial 2.5 to around 5.4-6.3 and achieving suitable pH condition for SRB growth. Sewage sludge contained fewer biodegradable organic substance, reactive mixture with single sewage sludge showed the lowest sulfate reduction (65.9%). When the single sewage sludge was supplemented with rice straw, SRB reducing sulfate was enhanced (79.2%), because the degradation rate of rice straw was accelerated by the specific bacteria in sewage sludge, providing relatively abundant carbon source for SRB. Control experiment with ethanol was most effective in promoting sulfate reduction (97.9%). Metal removal efficiency in all three reactors was as high as 99% for copper, early copper removal was mainly attributed to the adsorption capacity of sewage sludge prior to SRB acclimation. It is feasible for using rice straw and sewage sludge as carbon sources for SRB treating acid mine drainage at a low cost, this may have significant implication for in situ bioremediation of mine environment. PMID:21090305

  9. Ferrous iron oxidation by Thiobacillus ferrooxidans: inhibition with benzoic acid, sorbic acid and sodium lauryl sulfate

    SciTech Connect

    Onysko, S.J.

    1984-07-01

    Acid mine drainage is formed by the weathering or oxidation of pyritic material exposed during coal mining. The rate of pyritic material oxidation can be greatly accelerated by certain acidophilic bacteria such as Thiobacillus ferrooxidans which catalyse the oxidation of ferrous to ferric iron. A number of organic compounds, under laboratory conditions, can apparently inhibit both the oxidation of ferrous to ferric iron by T. ferrooxidans and the weathering of pyritic material by mixed cultures of acid mine drainage micro-organisms. Sodium lauryl sulphate (SLS), an anionic surfactant has proved effective in this respect. Benzoic acid, sorbic acid and SLS at low concentrations, each effectively inhibited bacterial oxidation of ferrous iron in batch cultures of T. ferrooxidans. The rate of chemical oxidation of ferrous iron in low pH, sterile, batch reactors was not substantially affected at the tested concentrations of any of the compounds.

  10. Gas chromatographic determination of sulfuric acid and application to urinary sulfate.

    PubMed

    Masuoka, N; Ubuka, T; Kinuta, M; Yoshida, S; Taguchi, T

    1988-10-01

    A new gas chromatographic method for the determination of sulfate was developed. In this method, sulfate was quantitatively converted to a volatile derivative, dimethyl sulfate, by a two-step procedure. First, sulfate was converted to silver sulfate by reaction with silver oxide, and then to dimethyl sulfate by reaction with methyl iodide. The derivative was analyzed by gas chromatography. Methyl methanesulfonate was used as an internal standard. The method was applied to the determination of total urinary sulfate. Phosphate and chloride ions, which interfered with the present method, were eliminated with the use of basic magnesium carbonate and an excess of silver oxide, respectively. Recovery was over 96% when 5 to 40 mumol/ml of sulfate was added to human urine samples. PMID:3223336

  11. Desulfosporosinus acididurans sp. nov.: an acidophilic sulfate-reducing bacterium isolated from acidic sediments.

    PubMed

    Sánchez-Andrea, Irene; Stams, Alfons J M; Hedrich, Sabrina; Ňancucheo, Ivan; Johnson, D Barrie

    2015-01-01

    Three strains of sulfate-reducing bacteria (M1(T), D, and E) were isolated from acidic sediments (White river and Tinto river) and characterized phylogenetically and physiologically. All three strains were obligately anaerobic, mesophilic, spore-forming straight rods, stained Gram-negative and displayed variable motility during active growth. The pH range for growth was 3.8-7.0, with an optimum at pH 5.5. The temperature range for growth was 15-40 °C, with an optimum at 30 °C. Strains M1(T), D, and E used a wide range of electron donors and acceptors, with certain variability within the different strains. The nominated type strain (M1(T)) used ferric iron, nitrate, sulfate, elemental sulfur, and thiosulfate (but not arsenate, sulfite, or fumarate) as electron acceptors, and organic acids (formate, lactate, butyrate, fumarate, malate, and pyruvate), alcohols (glycerol, methanol, and ethanol), yeast extract, and sugars (xylose, glucose, and fructose) as electron donors. It also fermented some substrates such as pyruvate and formate. Strain M1(T) tolerated up to 50 mM ferrous iron and 10 mM aluminum, but was inhibited by 1 mM copper. On the basis of phenotypic, phylogenetic, and genetic characteristics, strains M1(T), D, and E represent a novel species within the genus Desulfosporosinus, for which the name Desulfosporosinus acididurans sp. nov. is proposed. The type strain is M1(T) (=DSM 27692(T) = JCM 19471(T)). Strain M1(T) was the first acidophilic SRB isolated, and it is the third described species of acidophilic SRB besides Desulfosporosinus acidiphilus and Thermodesulfobium narugense.

  12. HIGH-TEMPERATURE, SHORT-TIME SULFATION OF CALCIUM- BASED SORBENTS. 2. EXPERIMENTAL DATA AND THEORETICAL MODEL PREDICTIONS

    EPA Science Inventory

    The fundamental processes for injection of CaCO3 and Ca(OH)2 for the removal of SO2 from combustion gases of coal-fired boilers are analyzed on the basis of experimental data and a comprehensive theoretical model. Sulfation data were obtained in a 30-kW isothermal gas-particle t...

  13. Secondary sulfate minerals associated with acid drainage in the eastern US: Recycling of metals and acidity in surficial environments

    USGS Publications Warehouse

    Hammarstrom, J.M.; Seal, R.R.; Meier, A.L.; Kornfeld, J.M.

    2005-01-01

    Weathering of metal-sulfide minerals produces suites of variably soluble efflorescent sulfate salts at a number of localities in the eastern United States. The salts, which are present on mine wastes, tailings piles, and outcrops, include minerals that incorporate heavy metals in solid solution, primarily the highly soluble members of the melanterite, rozenite, epsomite, halotrichite, and copiapite groups. The minerals were identified by a combination of powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron-microprobe. Base-metal salts are rare at these localities, and Cu, Zn, and Co are commonly sequestered as solid solutions within Fe- and Fe-Al sulfate minerals. Salt dissolution affects the surface-water chemistry at abandoned mines that exploited the massive sulfide deposits in the Vermont copper belt, the Mineral district of central Virginia, the Copper Basin (Ducktown) mining district of Tennessee, and where sulfide-bearing metamorphic rocks undisturbed by mining are exposed in Great Smoky Mountains National Park in North Carolina and Tennessee. Dissolution experiments on composite salt samples from three minesites and two outcrops of metamorphic rock showed that, in all cases, the pH of the leachates rapidly declined from 6.9 to 30 mg L-1), Fe (>47 mg L-1), sulfate (>1000 mg L-1), and base metals (>1000 mg L-1 for minesites, and 2 mg L-1 for other sites). Geochemical modeling of surface waters, mine-waste leachates, and salt leachates using PHREEQC software predicted saturation in the observed ochre minerals, but significant concentration by evaporation would be needed to reach saturation in most of the sulfate salts. Periodic surface-water monitoring at Vermont minesites indicated peak annual metal loads during spring runoff. At the Virginia site, where no winter-long snowpack develops, metal loads were highest during summer months when salts were dissolved periodically by rainstorms following sustained evaporation during dry

  14. Microbial biofilms control economic metal mobility in an acid-sulfate hydrothermal system

    NASA Astrophysics Data System (ADS)

    Phillips-Lander, C. M.; Roberts, J. A.; Hernandez, W.; Mora, M.; Fowle, D. A.

    2012-12-01

    Trace metal cycling in hydrothermal systems has been the subject of a variety of geochemical and economical geology studies. Typically in these settings these elements are sequestered in sulfide and oxide mineral fractions, however in near-surface low-temperature environments organic matter and microorganisms (typically in mats) have been implicated in their mobility through sorption. Here we specifically examine the role of microbial biofilms on metal partitioning in an acid-sulfate hydrothermal system. We studied the influence of microorganisms and microbial biofilms on trace metal adsorption in Pailas de Aguas I, an acid-sulfate hot spring on the southwest flank of Rincon de la Vieja, a composite stratovolcano in the Guanacaste Province, Costa Rica. Spring waters contain high suspended loads, and are characterized by high T (79.6-89.3oC), low pH (2.6-4), and high ionic strengths (I= 0.5-0.8). Waters contain high concentrations of the biogeochemically active elements Fe (4-6 mmol/l) and SO42- (38 mmol/l), but PO43- are below detection limits (bdl). Silver, Ni, and Mo concentrations are bdl; however other trace metals are present in solution in concentrations of 0.1-0.2 mg/l Cd, 0.2-0.4 mg/l Cr and V, 0.04-1 mg/l Cu,. Preliminary 16S rRNA analyses of microorganisms in sediments reveal several species of algae, including Galderia sp., Cyanidium sp, γ-proteobacteria, Acidithiobacillus caldus, Euryarcheota, and methanogens. To evaluate microbial biofilms' impact on trace metal mobility we analyzed a combination of suspended, bulk and biofilm associated sediment samples via X-ray diffraction (XRD) and trace element sequential extractions (SE). XRD analysis indicated all samples were primarily composed of Fe/Al clay minerals (nontronite, kaolinite), 2- and 6-line ferrihydrite, goethite, and hematite, quartz, and opal-α. SE showed the highest concentrations of Cu, Mo, and V were found in the suspended load. Molybdenum was found primarily in the residual and organic

  15. Advances in biotreatment of acid mine drainage and biorecovery of metals: 2. Membrane bioreactor system for sulfate reduction.

    PubMed

    Tabak, Henry H; Govind, Rakesh

    2003-12-01

    Several biotreatmemt techniques for sulfate conversion by the sulfate reducing bacteria (SRB) have been proposed in the past, however few of them have been practically applied to treat sulfate containing acid mine drainage (AMD). This research deals with development of an innovative polypropylene hollow fiber membrane bioreactor system for the treatment of acid mine water from the Berkeley Pit, Butte, MT, using hydrogen consuming SRB biofilms. The advantages of using the membrane bioreactor over the conventional tall liquid phase sparged gas bioreactor systems are: large microporous membrane surface to the liquid phase; formation of hydrogen sulfide outside the membrane, preventing the mixing with the pressurized hydrogen gas inside the membrane; no requirement of gas recycle compressor; membrane surface is suitable for immobilization of active SRB, resulting in the formation of biofilms, thus preventing washout problems associated with suspended culture reactors; and lower operating costs in membrane bioreactors, eliminating gas recompression and gas recycle costs. Information is provided on sulfate reduction rate studies and on biokinetic tests with suspended SRB in anaerobic digester sludge and sediment master culture reactors and with SRB biofilms in bench-scale SRB membrane bioreactors. Biokinetic parameters have been determined using biokinetic models for the master culture and membrane bioreactor systems. Data are presented on the effect of acid mine water sulfate loading at 25, 50, 75 and 100 ml/min in scale-up SRB membrane units, under varied temperatures (25, 35 and 40 degrees C) to determine and optimize sulfate conversions for an effective AMD biotreatment. Pilot-scale studies have generated data on the effect of flow rates of acid mine water (MGD) and varied inlet sulfate concentrations in the influents on the resultant outlet sulfate concentration in the effluents and on the number of SRB membrane modules needed for the desired sulfate conversion in

  16. Advances in biotreatment of acid mine drainage and biorecovery of metals: 2. Membrane bioreactor system for sulfate reduction.

    PubMed

    Tabak, Henry H; Govind, Rakesh

    2003-12-01

    Several biotreatmemt techniques for sulfate conversion by the sulfate reducing bacteria (SRB) have been proposed in the past, however few of them have been practically applied to treat sulfate containing acid mine drainage (AMD). This research deals with development of an innovative polypropylene hollow fiber membrane bioreactor system for the treatment of acid mine water from the Berkeley Pit, Butte, MT, using hydrogen consuming SRB biofilms. The advantages of using the membrane bioreactor over the conventional tall liquid phase sparged gas bioreactor systems are: large microporous membrane surface to the liquid phase; formation of hydrogen sulfide outside the membrane, preventing the mixing with the pressurized hydrogen gas inside the membrane; no requirement of gas recycle compressor; membrane surface is suitable for immobilization of active SRB, resulting in the formation of biofilms, thus preventing washout problems associated with suspended culture reactors; and lower operating costs in membrane bioreactors, eliminating gas recompression and gas recycle costs. Information is provided on sulfate reduction rate studies and on biokinetic tests with suspended SRB in anaerobic digester sludge and sediment master culture reactors and with SRB biofilms in bench-scale SRB membrane bioreactors. Biokinetic parameters have been determined using biokinetic models for the master culture and membrane bioreactor systems. Data are presented on the effect of acid mine water sulfate loading at 25, 50, 75 and 100 ml/min in scale-up SRB membrane units, under varied temperatures (25, 35 and 40 degrees C) to determine and optimize sulfate conversions for an effective AMD biotreatment. Pilot-scale studies have generated data on the effect of flow rates of acid mine water (MGD) and varied inlet sulfate concentrations in the influents on the resultant outlet sulfate concentration in the effluents and on the number of SRB membrane modules needed for the desired sulfate conversion in

  17. Regeneration of sulfated metal oxides and carbonates

    DOEpatents

    Hubble, Bill R.; Siegel, Stanley; Cunningham, Paul T.

    1978-03-28

    Alkali metal or alkaline earth metal carbonates such as calcium carbonate and magnesium carbonate found in dolomite or limestone are employed for removal of sulfur dioxide from combustion exhaust gases. The sulfated carbonates are regenerated to oxides through use of a solid-solid reaction, particularly calcium sulfide with calcium sulfate to form calcium oxide and sulfur dioxide gas. The regeneration is performed by contacting the sulfated material with a reductant gas such as hydrogen within an inert diluent to produce calcium sulfide in mixture with the sulfate under process conditions selected to permit the sulfide-sulfate, solid-state reaction to occur.

  18. Adsorption and release of amino acids mixture onto apatitic calcium phosphates analogous to bone mineral

    NASA Astrophysics Data System (ADS)

    El Rhilassi, A.; Mourabet, M.; El Boujaady, H.; Bennani-Ziatni, M.; Hamri, R. El; Taitai, A.

    2012-10-01

    Study focused on the interaction of adsorbate with poorly crystalline apatitic calcium phosphates analogous to bone mineral. Calcium phosphates prepared in water-ethanol medium at physiological temperature (37 °C) and neutral pH, their Ca/P ratio was between 1.33 and 1.67. Adsorbate used in this paper takes the mixture form of two essential amino acids L-lysine and DL-leucine which have respectively a character hydrophilic and hydrophobic. Adsorption and release are investigated experimentally; they are dependent on the phosphate type and on the nature of adsorbate L-lysine, DL-leucine and their mixture. Adsorption of mixture of amino acids on the apatitic calcium phosphates is influenced by the competition between the two amino acids: L-lysine and DL-leucine which exist in the medium reaction. The adsorption kinetics is very fast while the release kinetics is slow. The chemical composition of apatite has an influence on both adsorption and release. The interactions adsorbate-adsorbent are electrostatic type. Adsorption and release reactions of the amino acid mixture are explained by the existence of the hydrated surface layer of calcium phosphate apatite. The charged sbnd COOsbnd and sbnd NH3+ of adsorbates are the strongest groups that interact with the surface of apatites, the adsorption is mainly due to the electrostatic interaction between the groups sbnd COOsbnd of amino acids and calcium Ca2+ ions of the apatite. Comparative study of interactions between adsorbates (L-lysine, DL-leucine and their mixture) and apatitic calcium phosphates is carried out in vitro by using UV-vis and infrared spectroscopy IR techniques.

  19. Ionic surfactant aggregates in saline solutions: sodium dodecyl sulfate (SDS) in the presence of excess sodium chloride (NaCl) or calcium chloride (CaCl(2)).

    PubMed

    Sammalkorpi, Maria; Karttunen, Mikko; Haataja, Mikko

    2009-04-30

    The properties of sodium dodecyl sulfate (SDS) aggregates in saline solutions of excess sodium chloride (NaCl) or calcium chloride (CaCl(2)) ions were studied through extensive molecular dynamics simulations with explicit solvent. We find that the ionic strength of the solution affects not only the aggregate size of the resulting anionic micelles but also their structure. Specifically, the presence of CaCl(2) induces more compact and densely packed micelles with a significant reduction in gauche defects in the SDS hydrocarbon chains in comparison with NaCl. Furthermore, we observe significantly more stable salt bridges between the charged SDS head groups mediated by Ca(2+) than Na(+). The presence of these salt bridges helps stabilize the more densely packed micelles.

  20. The selective activation of the cardiac sarcolemmal sodium-calcium exchanger by plasmalogenic phosphatidic acid produced by phospholipase D.

    PubMed

    Hale, C C; Ebeling, E G; Hsu, F F; Ford, D A

    1998-01-30

    Since plasmalogens are the predominant phospholipid of cardiac sarcolemma, the activation of the sodium-calcium exchanger by either plasmenylethanolamine or plasmalogenic phosphatidic acid generated by phospholipase D was explored. Sodium-calcium exchange activity was 7-fold greater in proteoliposomes comprised of plasmenylethanolamine compared to proteoliposomes comprised of only plasmenylcholine. Phospholipase D treatment of proteoliposomes resulted in 1 mol % conversion of plasmenylcholine or phosphatidylcholine to their respective phosphatidic acid molecular species with a concomitant 8-fold or 2-fold activation of sodium-calcium exchange activity, respectfully. Thus, phospholipase D-mediated hydrolysis of plasmalogens to phosphatidic acid may be an important mechanism for the regulation of the sodium-calcium exchanger.

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

    SciTech Connect

    Shen, Z.X.; Guan, B.H.; Fu, H.L.; Yang, L.C.

    2009-12-15

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

  2. Production of citric and oxalic acids and solubilization of calcium phosphate by Penicillium bilaii.

    PubMed Central

    Cunningham, J E; Kuiack, C

    1992-01-01

    An isolate of Penicillium bilaii previously reported to solubilize mineral phosphates and enhance plant uptake of phosphate was studied. Using agar media with calcium phosphate and the pH indicator alizarin red S, the influence of the medium composition on phosphate solubility and medium acidification was recorded. The major acidic metabolites produced by P. bilaii in a sucrose nitrate liquid medium were found to be oxalic acid and citric acid. Citric acid production was promoted under nitrogen-limited conditions, while oxalic acid production was promoted under carbon-limited conditions. Citric acid was produced in both growth and stationary phases, but oxalic acid production occurred only in stationary phase. When submerged cultures which normally produce acid were induced to sporulate, the culture medium shifted toward alkaline rather than acid reaction with growth. PMID:1622211

  3. Separation of membranes from acid-solubilized fish muscle proteins with the aid of calcium ions and organic acids.

    PubMed

    Liang, Yong; Hultin, Herbert O

    2005-04-20

    Calcium chloride, and to a lesser extent MgCl2, aided in the separation of membranes by centrifugation from cod (Gadus morhua) muscle homogenates solubilized at pH 3 in the presence of citric acid or malic acid but not lactic acid. Adding citric acid and Ca2+ before solubilizing the cod muscle homogenates was needed for the effect. At 1 mM citric acid, 70-80% of the phospholipid and 25-30% of the protein were removed at 10 mM Ca2+. At 8 mM Ca2+, citric acid showed an optimal effect on phospholipid removal at 5 mM with 90% of the phospholipid and 35% of the protein removed. The treatment with citric acid and Ca2+ was also effective in separating the membrane from solubilized herring (Clupea harengus) muscle homogenate. Ca2+ and citric acid might exert their influence by disconnecting linkages between membranes and cytoskeletal proteins.

  4. Short term tolvaptan increases water intake and effectively decreases urinary calcium oxalate, calcium phosphate, and uric acid supersaturations

    PubMed Central

    Cheungpasitporn, Wisit; Erickson, Stephen B.; Rule, Andrew D.; Enders, Felicity; Lieske, John C.

    2016-01-01

    Purpose Many patients cannot effectively increase water intake and urine volume to prevent urinary stones. Tolvaptan, a V2 receptor antagonist, blocks water reabsorption in the collecting duct and should reduce urinary supersaturation (SS) of stone forming solutes, but this has never been proven. Materials and Methods We conducted a double blind, randomized, placebo-controlled, crossover study in 21 adult calcium urinary stone formers stratified as majority calcium oxalate(CaOx, n=10) or calcium phosphate(CaP, n=11). Patients received tolvaptan 45 mg/day or placebo for 1 week, followed by a washout week and crossover to tolvaptan or placebo for week 3. A 24h urines was collected at the end of weeks 1 and 3. Results Tolvaptan vs. placebo decreased urinary osmolality (204±96 vs 529±213 mOsm/kg, P<0.001) and increased urinary volume (4.8±2.9 vs 1.8±0.9 L, P<0.001). The majority of urinary solute excretion rates including sodium and calcium did not significantly change, although oxalate secretion slightly increased (23±8 to 15±8 mg/24h, P = 0.009). Urinary CaOx SS (−0.01±1.14 vs 0.95±0.87 DG, P<0.001), CaP SS (−1.66±1.17 vs −0.13±1.02 DG, P<0.001) and Uric Acid SS (−2.05±4.05 vs −5.24±3.12 DG, P=0.04) all dramatically decreased. Effects did not differ between CaOx and CaP groups (P>0.05 for all interactions). Conclusions Tolvaptan increases urine volume and decreases urinary SS in calcium stone formers. Further study is needed to determine if long term use of V2 receptor antagonists results in fewer stone events. PMID:26598423

  5. Maleic Acid--but Not Structurally Related Methylmalonic Acid--Interrupts Energy Metabolism by Impaired Calcium Homeostasis.

    PubMed

    Tuncel, Ali Tunç; Ruppert, Thorsten; Wang, Bei-Tzu; Okun, Jürgen Günther; Kölker, Stefan; Morath, Marina Alexandra; Sauer, Sven Wolfgang

    2015-01-01

    Maleic acid (MA) has been shown to induce Fanconi syndrome via disturbance of renal energy homeostasis, though the underlying pathomechanism is still under debate. Our study aimed to examine the pathomechanism underlying maleic acid-induced nephrotoxicity. Methylmalonic acid (MMA) is structurally similar to MA and accumulates in patients affected with methymalonic aciduria, a defect in the degradation of branched-chain amino acids, odd-chain fatty acids and cholesterol, which is associated with the development of tubulointerstitial nephritis resulting in chronic renal failure. We therefore used MMA application as a control experiment in our study and stressed hPTECs with MA and MMA to further validate the specificity of our findings. MMA did not show any toxic effects on proximal tubule cells, whereas maleic acid induced concentration-dependent and time-dependent cell death shown by increased lactate dehydrogenase release as well as ethidium homodimer and calcein acetoxymethyl ester staining. The toxic effect of MA was blocked by administration of single amino acids, in particular L-alanine and L-glutamate. MA application further resulted in severe impairment of cellular energy homeostasis on the level of glycolysis, respiratory chain, and citric acid cycle resulting in ATP depletion. As underlying mechanism we could identify disturbance of calcium homeostasis. MA toxicity was critically dependent on calcium levels in culture medium and blocked by the extra- and intracellular calcium chelators EGTA and BAPTA-AM respectively. Moreover, MA-induced cell death was associated with activation of calcium-dependent calpain proteases. In summary, our study shows a comprehensive pathomechanistic concept for MA-induced dysfunction and damage of human proximal tubule cells. PMID:26086473

  6. Reactive transport controls on sandy acid sulfate soils and impacts on shallow groundwater quality

    NASA Astrophysics Data System (ADS)

    Salmon, S. Ursula; Rate, Andrew W.; Rengel, Zed; Appleyard, Steven; Prommer, Henning; Hinz, Christoph

    2014-06-01

    Disturbance or drainage of potential acid sulfate soils (PASS) can result in the release of acidity and degradation of infrastructure, water resources, and the environment. Soil processes affecting shallow groundwater quality have been investigated using a numerical code that integrates (bio)geochemical processes with water, solute, and gas transport. The patterns of severe and persistent acidification (pH < 4) in the sandy, carbonate-depleted podzols of a coastal plain could be reproduced without calibration, based on oxidation of microcrystalline pyrite after groundwater level decrease and/or residual groundwater acidity, due to slow vertical solute transport rates. The rate of acidification was limited by gas phase diffusion of oxygen and hence was sensitive to soil water retention properties and in some cases also to oxygen consumption by organic matter mineralization. Despite diffusion limitation, the rate of oxidation in sandy soils was rapid once pyrite-bearing horizons were exposed, even to a depth of 7.5 m. Groundwater level movement was thus identified as an important control on acidification, as well as the initial pyrite content. Increase in the rate of Fe(II) oxidation lead to slightly lower pH and greater accumulation of Fe(III) phases, but had little effect on the overall amount of pyrite oxidized. Aluminosilicate (kaolinite) dissolution had a small pH-buffering effect but lead to the release of Al and associated acidity. Simulated dewatering scenarios highlighted the potential of the model for risk assessment of (bio)geochemical impacts on soil and groundwater over a range of temporal and spatial scales.

  7. Preparation and Acid Catalytic Activity of TiO2 Grafted Silica MCM-41 with Sulfate Treatment

    NASA Astrophysics Data System (ADS)

    Guo, Dai-shi; Ma, Zi-feng; Yin, Chun-sheng; Jiang, Qi-zhong

    2008-02-01

    TiO2 grafted silica MCM-41 catalyst with and without sulfate treatment were prepared. The structural and acid properties of these materials were investigated by XRD, N2 adsorption-desorption, element analysis, thermal analysis, Raman and FTIR measurements. Their acid-catalytic activities were evaluated using the cyclization reaction of pseudoionone. It was found that the obtained materials possess well-ordered mesostructure, and the grafted TiO2 components were in highly dispersed amorphous form. T/MCM41 without sulfation contained only Lewis acid sites, while Brønsted and Lewis acidities were remarkably improved for the sulfated materials ST/MCM41 and d-ST/MCM41. T/MCM-41 was not active for the cyclization reaction of pseudoionone, but ST/MCM-41 and d-ST/MCM-41 possessed favorable catalytic activities. The catalytic performance of ST/MCM-41 was comparable with that of the commercial solid acid catalyst of Amberlyst-15, and better than that of d-ST/MCM-41, although the latter underwent a second TiO2 grafting process and accordingly had higher Ti and S content. The specific surface structure of Si-O-Ti-O-S=O in ST/MCM-41 and the bilateral induction effect of Si and S=O on Si-O-Ti bonds were speculated to account for its higher acid catalytic activity.

  8. Preparation and application of zirconium sulfate supported on SAPO-34 molecular sieve as solid acid catalyst for esterification

    SciTech Connect

    Xu, Dongyan Ma, Hong; Cheng, Fei

    2014-05-01

    Graphical abstract: - Highlights: • SAPO-34 supported zirconium sulfate solid acid catalyst was prepared. • Esterification of acetic acid with ethanol can be catalyzed by ZS/SAPO-34. • The hydration of ZS is vital to the acidic property and catalytic performance. • The ZS/SAPO-34 catalyst treated at 200 °C shows good reusability. - Abstract: Zirconium sulfate (ZS) was supported on SAPO-34 molecular sieve by using an incipient wetness impregnation method with zirconium sulfate as the precursor. The as-prepared catalysts were used as solid acid catalyst for esterification reaction of acetic acid with ethanol. The influence of calcination temperature on the acidic property, catalytic activity, and reusability of ZS/SAPO-34 catalysts were mainly investigated. FT-IR, SEM, EDS and TG analysis have been carried out to demonstrate the characteristics of ZS/SAPO-34 catalysts. It was found that the 30 wt%ZS/SAPO-34 catalysts display the property of superacid irrespective of calcination temperature. The ZS/SAPO-34 catalyst treated at 200 °C can enhance the interaction between the supported ZS and SAPO-34 and keep the catalyst remaining substantially active after several reaction cycles. However, further increasing calcination temperature will cause the transfer of ZS from hydrate to anhydrous phase, and thus the decrease of activity.

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

    NASA Technical Reports Server (NTRS)

    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 <150 micron fines from ten sites at Gale Crater. Three were in Yellowknife Bay: the Rocknest aeolian bedform (RN) and drilled Sheepbed mudstone from sites John Klein (JK) and Cumberland (CB). One was drilled from the Windjana (WJ) site on a sandstone of the Kimberly formation. Four were drilled from sites Confidence Hills (CH), Mojave (MJ), Telegraph Peak (TP) and Buckskin (BK) of the Murray Formation at the base of Mt. Sharp. Two were drilled from sandstones of the Stimson formation targeting relatively unaltered (Big Sky, BY) and then altered (Greenhorn, GH) material associated with a light colored fracture zone. CheMin analyses provided quantitative sample mineralogy. SAM's evolved gas analysis mass spectrometry (EGA-MS) detected H2O, CO2, O2, H2, SO2, H2S, HCl, NO, and other trace gases. This contribution will focus on evolved SO2. All samples evolved SO2 above 500 C. The shapes of the SO2 evolution traces with temperature vary between samples but most have at least two "peaks' within the wide high temperature evolution, from approx. 500-700 and approx. 700-860 C (Fig. 1). In many cases, the only sulfur minerals detected with CheMin were Ca sulfates (e.g., RN and GH), which should thermally decompose at temperatures above those obtainable by SAM (>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

  10. Copper-Sulfate Pentahydrate as a Product of the Waste Sulfuric Acid Solution Treatment

    NASA Astrophysics Data System (ADS)

    Marković, Radmila; Stevanović, Jasmina; Avramović, Ljiljana; Nedeljković, Dragutin; Jugović, Branimir; Stajić-Trošić, Jasna; Gvozdenović, Milica

    2012-12-01

    The aim of this study is synthesis of copper-sulfate pentahydrate from the waste sulfuric acid solution-mother liquor generated during the regeneration process of copper bleed solution. Copper is removed from the mother liquor solution in the process of the electrolytic treatment using the insoluble lead anodes alloyed with 6 mass pct of antimony on the industrial-scale equipment. As the result of the decopperization process, copper is removed in the form of the cathode sludge and is precipitated at the bottom of the electrolytic cell. By this procedure, the content of copper could be reduced to the 20 mass pct of the initial value. Chemical characterization of the sludge has shown that it contains about 90 mass pct of copper. During the decopperization process, the very strong poison, arsine, can be formed, and the process is in that case terminated. The copper leaching degree of 82 mass pct is obtained using H2SO4 aqueous solution with the oxygen addition during the cathode sludge chemical treatment at 80 °C ± 5 °C. Obtained copper salt satisfies the requirements of the Serbian Standard for Pesticide, SRPS H.P1. 058. Therefore, the treatment of waste sulfuric acid solutions is of great economic and environmental interest.

  11. Amino acid sequence surrounding the chondroitin sulfate attachment site of thrombomodulin regulates chondroitin polymerization.

    PubMed

    Izumikawa, Tomomi; Kitagawa, Hiroshi

    2015-05-01

    Thrombomodulin (TM) is a cell-surface glycoprotein and a critical mediator of endothelial anticoagulant function. TM exists as both a chondroitin sulfate (CS) proteoglycan (PG) form and a non-PG form lacking a CS chain (α-TM); therefore, TM can be described as a part-time PG. Previously, we reported that α-TM bears an immature, truncated linkage tetrasaccharide structure (GlcAβ1-3Galβ1-3Galβ1-4Xyl). However, the biosynthetic mechanism to generate part-time PGs remains unclear. In this study, we used several mutants to demonstrate that the amino acid sequence surrounding the CS attachment site influences the efficiency of chondroitin polymerization. In particular, the presence of acidic residues surrounding the CS attachment site was indispensable for the elongation of CS. In addition, mutants defective in CS elongation did not exhibit anti-coagulant activity, as in the case with α-TM. Together, these data support a model for CS chain assembly in which specific core protein determinants are recognized by a key biosynthetic enzyme involved in chondroitin polymerization.

  12. Eliminating aluminum toxicity in an acid sulfate soil for rice cultivation using plant growth promoting bacteria.

    PubMed

    Panhwar, Qurban Ali; Naher, Umme Aminun; Radziah, Othman; Shamshuddin, Jusop; Razi, Ismail Mohd

    2015-01-01

    Aluminum toxicity is widely considered as the most important limiting factor for plants growing in acid sulfate soils. A study was conducted in laboratory and in field to ameliorate Al toxicity using plant growth promoting bacteria (PGPB), ground magnesium limestone (GML) and ground basalt. Five-day-old rice seedlings were inoculated by Bacillus sp., Stenotrophomonas maltophila, Burkholderia thailandensis and Burkholderia seminalis and grown for 21 days in Hoagland solution (pH 4.0) at various Al concentrations (0, 50 and 100 μM). Toxicity symptoms in root and leaf were studied using scanning electron microscope. In the field, biofertilizer (PGPB), GML and basalt were applied (4 t·ha-1 each). Results showed that Al severely affected the growth of rice. At high concentrations, the root surface was ruptured, leading to cell collapse; however, no damages were observed in the PGPB inoculated seedlings. After 21 days of inoculation, solution pH increased to >6.0, while the control treatment remained same. Field study showed that the highest rice growth and yield were obtained in the bio-fertilizer and GML treatments. This study showed that Al toxicity was reduced by PGPB via production of organic acids that were able to chelate the Al and the production of polysaccharides that increased solution pH. The release of phytohormones further enhanced rice growth that resulted in yield increase. PMID:25710843

  13. Laboratory simulations of acid-sulfate weathering under volcanic hydrothermal conditions: Implications for early Mars

    PubMed Central

    Marcucci, Emma C; Hynek, Brian M

    2014-01-01

    We have completed laboratory experiments and thermochemical equilibrium models to investigate secondary mineral formation under conditions akin to volcanic, hydrothermal acid-sulfate weathering systems. Our research used the basaltic mineralogy at Cerro Negro Volcano, Nicaragua, characterized by plagioclase, pyroxene, olivine, and volcanic glass. These individual minerals and whole-rock field samples were reacted in the laboratory with 1 molal sulfuric acid at varying temperatures (65, 150, and 200°C), fluid:rock weight ratios (1:1, 4:1, and 10:1), and durations (1–60 days). Thermochemical equilibrium models were developed using Geochemist's Workbench. To understand the reaction products and fluids, we employed scanning electron microscopy/energy dispersive spectroscopy, X-ray diffraction, and inductively coupled plasma-atomic emission spectroscopy. The results of our experiments and models yielded major alteration minerals that include anhydrite, natroalunite, minor iron oxide, and amorphous Al-Si gel. We found that variations in experimental parameters did not drastically change the suite of minerals produced; instead, abundance, size, and crystallographic shape changed. Our results also suggest that it is essential to separate phases formed during experiments from those formed during fluid evaporation to fully understand the reaction processes. Our laboratory reacted and model predicted products are consistent with the mineralogy observed at places on Mars. However, our results indicate that determination of the formation conditions requires microscopic imagery and regional context, as well as a thorough understanding of contributions from both experiment precipitation and fluid evaporation minerals. PMID:26213665

  14. Biological hydrogel synthesized from hyaluronic acid, gelatin and chondroitin sulfate by click chemistry.

    PubMed

    Hu, Xiaohong; Li, Dan; Zhou, Feng; Gao, Changyou

    2011-04-01

    In order to mimic the natural cartilage extracellular matrix, which is composed of core proteins and glycosaminoglycans, a biological hydrogel was synthesized from the biopolymers hyaluronic acid (HA), chondroitin sulfate (CS) and gelatin via click chemistry. HA and CS were modified with 11-azido-3,6,9-trioxaundecan-1-amine (AA) and gelatin was modified with propiolic acid (PA). The molecular structures were verified by (1)H nuclear magnetic resonance, infrared spectroscopy and elemental analysis, giving substitution degrees of 29%, 89% and 44% for HA-AA, CS-AA and gelatin-PA (G-PA), respectively. The -N(3) groups of HA-AA and CS-AA were reacted with the acetylene groups of G-PA, catalyzed by Cu(I), to form triazole rings, thereby forming a cross-linked hydrogel. The gelation time was decreased monotonically with increasing Cu(I) concentration up to 0.95 mg ml(-1). The hydrogel obtained was in a highly swollen state and showed the characteristics of an elastomer. Incubation in phosphate-buffered saline for 4 weeks resulted in a weight loss of up to 45%. Moreover, about 20% gelatin and 10% CS were released from the hydrogel in 2 weeks. In vitro cell culture showed that the hydrogel could support the adhesion and proliferation of chondrocytes. PMID:21145437

  15. Role of dissimilatory sulfate reduction in wetlands constructed for acid coal mine drainage (AMD) treatment. Master's thesis

    SciTech Connect

    Taddeo, F.J.

    1991-08-14

    Five constructed wetlands with different organic substrates were exposed to the same quantity/quality of acid mine drainage (AMD). During the 16-month exposure to AMD, all wetlands accumulated S in the forms of organic and reduced inorganic S and Fe in the form of iron sulfides. Iron sulfide and probably most of the organic S(C-bonded S) accumulation were end products of bacterial dissimilatory sulfate reduction. Results of study support the notion that sulfate reduction and accumulation of Fe sulfides contribute to Fe retention in wetlands exposed to AMD. Detailed information is provided.

  16. Alleviating aluminium toxicity on an acid sulphate soils in Peninsular Malaysia with application of calcium silicate

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

    A study was conducted to alleviate Al toxicity of an acid sulphate soils collected from paddy cultivation area in Kedah, Peninsular Malaysia. For this purpose, the collected acid sulphate soils were treated with calcium silicate. The treated soils were incubated for 120 days in submerged condition in a glasshouse. Subsamples were collected every 30 days throughout the incubation period. Soil pH and exchangeable Al showed positive effect; soil pH increased from 2.9 to 3.5, meanwhile exchangeable Al was reduced from 4.26 to 0.82 cmolc kg-1, which was well below the critical Al toxicity level for rice growth of 2 cmolc kg-1. It was noted that the dissolution of calcium silicate (CaSiO3) supplied substantial amount of Ca2+ and H4SiO42- ions into the soil, noted with increment in Si (silicate) content from 21.21 to 40 mg kg-1 at day 30 and reduction of exchangeable Al at day 90 from 4.26 to below 2 cmolc kg-1. During the first 60 days of incubation, Si content was positively correlated with soil pH, while the exchangeable Al was negatively correlated with Si content. It is believed that the silicate anions released by calcium silicate were active in neutralizing H+ ions that governs the high acidity (pH 2.90) of the acid sulphate soils. This scenario shows positive effect of calcium silicate to reduce soil acidity, therefore creates a favourable soil condition for good rice growth during its vegetative phase (30 days). Thus, application of calcium silicate to alleviate Al toxicity of acid sulphate soils for rice cultivation is a good soil amendment.

  17. Contemporaneous deposition of phyllosilicates and sulfates: Using Australian acidic saline lake deposits to describe geochemical variability on Mars

    USGS Publications Warehouse

    Baldridge, A.M.; Hook, S.J.; Crowley, J.K.; Marion, G.M.; Kargel, J.S.; Michalski, J.L.; Thomson, B.J.; de Souza, Filho C.R.; Bridges, N.T.; Brown, A.J.

    2009-01-01

    Studies of the origin of the Martian sulfate and phyllosilicate deposits have led to the hypothesis that there was a marked, global-scale change in the Mars environment from circum-neutral pH aqueous alteration in the Noachian to an acidic evaporitic system in the late Noachian to Hesperian. However, terrestrial studies suggest that two different geochemical systems need not be invoked to explain such geochemical variation.Western Australian acidic playa lakes have large pH differences separated vertically and laterally by only a few tens of meters, demonstrating how highly variable chemistries can coexist over short distances in natural environments. We suggest diverse and variable Martian aqueous environments where the coetaneous formation of phyllosilicates and sulfates at the Australian sites are analogs for regions where phyllosilicates and sulfates coexist on Mars. In these systems, Fe and alkali earth phyllosilicates represent deep facies associated with upwelling neutral to alkaline groundwater, whereas aluminous phyllosilicates and sulfates represent near-surface evaporitic facies formed from more acidic brines. Copyright 2009 by the American Geophysical Union.

  18. 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

    PubMed Central

    Ghorbanzadeh, Abdollah; Aminsobhani, Mohsen; Khoshzaban, Ahad; Abbaszadeh, Armin; Ghorbanzadeh, Atiyeh; Shamshiri, Ahmad Reza

    2015-01-01

    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 osteogenic 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/calcium sulfate (CS) mixture significantly promoted cell growth in comparison to pure 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. PMID:26877731

  19. Oxidation of Gas-Phase SO2 on the Surfaces of Acidic Microdroplets: Implications for Sulfate and Sulfate Radical Anion Formation in the Atmospheric Liquid Phase.

    PubMed

    Hung, Hui-Ming; Hoffmann, Michael R

    2015-12-01

    The oxidation of SO2(g) on the interfacial layers of microdroplet surfaces was investigated using a spray-chamber reactor coupled to an electrospray ionization mass spectrometer. Four major ions, HSO3(-), SO3(•-), SO4(•-) and HSO4(-), were observed as the SO2(g)/N2(g) gas-mixture was passed through a suspended microdroplet flow, where the residence time in the dynamic reaction zone was limited to a few hundred microseconds. The relatively high signal intensities of SO3(•-), SO4(•-), and HSO4(-) compared to those of HSO3(-) as observed at pH < 3 without addition of oxidants other than oxygen suggests an efficient oxidation pathway via sulfite and sulfate radical anions on droplets possibly via the direct interfacial electron transfer from HSO3(-) to O2. The concentrations of HSO3(-) in the aqueous aerosol as a function of pH were controlled by the deprotonation of hydrated sulfur dioxide, SO2·H2O, which is also affected by the pH dependent uptake coefficient. When H2O2(g) was introduced into the spray chamber simultaneously with SO2(g), HSO3(-) is rapidly oxidized to form bisulfate in the pH range of 3 to 5. Conversion to sulfate was less at pH < 3 due to relatively low HSO3(-) concentration caused by the fast interfacial reactions. The rapid oxidation of SO2(g) on the acidic microdroplets was estimated as 1.5 × 10(6) [S(IV)] (M s(-1)) at pH ≤ 3. In the presence of acidic aerosols, this oxidation rate is approximately 2 orders of magnitude higher than the rate of oxidation with H2O2(g) at a typical atmospheric H2O2(g) concentration of 1 ppb. This finding highlights the relative importance of the acidic surfaces for SO2 oxidation in the atmosphere. Surface chemical reactions on aquated aerosol surfaces, as observed in this study, are overlooked in most atmospheric chemistry models. These reaction pathways may contribute to the rapid production of sulfate aerosols that is often observed in regions impacted by acidic haze aerosol such as Beijing and other

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

    PubMed

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

    2015-12-01

    Processes involved in thermal desorption of benzoic acid from sodium and calcium montmorillonite clays are investigated by using variable temperature diffuse reflection Fourier transform infrared spectroscopy (DRIFTS). By monitoring the temperature dependence of infrared absorbance bands while heating samples, subtle changes in molecular vibrations are detected and employed to characterize specific benzoic acid adsorption sites. Abrupt changes in benzoic acid adsorption site properties occur for both clay samples at about 125 °C. Difference spectra absorbance band frequency variations indicate that adsorbed benzoic acid interacts with interlayer cations through water bridges and that these interactions can be disrupted by the presence of organic anions, in particular, benzoate. PMID:26647147

  1. Palmitoleic acid calcium salt: a lubricant and bactericidal powder from natural lipids.

    PubMed

    Yamamoto, Yoshiaki; Kawamura, Yuki; Yamazaki, Yuki; Kijima, Tatsuro; Morikawa, Toshiya; Nonomura, Yoshimune

    2015-01-01

    Palmitoleic acid is a promising bactericidal agent for cleansing products with alternative bactericidal abilities. In this study, we focus on the physical and biological activity of palmitoleic acid calcium salt (C16:1 fatty acid Ca salt) because it forms via an ion-exchange reaction between palmitoleic acid and Ca ions in tap water, and remains on the skin surface during the cleansing process. Here, we prepared C16:1 fatty acid Ca salt to investigate its crystal structure and physical and bactericidal properties. The Ca salt was a plate-shaped lamellar crystalline powder with a particle diameter of several micrometers to several tens of micrometers; it exhibited significant lubricity and alternative bactericidal activity against Staphylococcus aureus (S. aureus) and Propionibacterium acnes (P. acnes). We also examined other fatty acid Ca salts prepared from lauric acid (C12:0 fatty acid), palmitic acid (C16:0 fatty acid), and oleic acid (C18:1 fatty acid). The bactericidal activities and lubricity of the fatty acid Ca salts changed with the alkyl chain length and the degree of unsaturation. The C16:1 fatty acid Ca salt exhibited the strongest selective bactericidal ability among the four investigated fatty acid Ca salts. These findings suggest that C16:1 fatty acid and its Ca salt have potential applications in cleansing and cosmetic products. PMID:25757432

  2. Influence of maleic acid copolymers on calcium orthophosphates crystallization at low temperature

    NASA Astrophysics Data System (ADS)

    Pelin, Irina M.; Popescu, Irina; Suflet, Dana M.; Aflori, Magdalena; Bulacovschi, Victor

    2013-08-01

    The goal of this study was to investigate the maleic acid copolymers role on calcium orthophosphates crystallization at low temperature. In this respect, two maleic acid copolymers with different structures [poly(sodium maleate-co-vinyl acetate) and poly(sodium maleate-co-methyl methacrylate)] were used. The syntheses of the calcium orthophosphates in the absence and in the presence of the copolymers were performed through the wet chemical method using calcium nitrate, ammonium dihydrogen phosphate and ammonium hydroxide as reactants. The syntheses were monitored in situ by potentiometric and conductometric measurements. To ensure the transformation of less thermodynamically stable calcium orthophosphates into more stable forms, the samples were aged 30 days in mother solutions, at room temperature. The presence of the copolymers in the final products was evidenced by FTIR spectroscopy and thermogravimetric analysis. Scanning and transmission electron microscopy and laser light scattering measurements gave information about the composites morphology and the size of the formed structures. X-ray diffraction evidenced that, as a function of comonomer structure and of copolymer concentration, the products could contain hydroxyapatite with low crystallinity, calcium-deficient or carbonated hydroxyapatite. At high concentration of poly(sodium maleate-co-methyl methacrylate) the transformation of brushite into apatitic structures was inhibited.

  3. Intra-Arterial Calcium Gluconate Treatment After Hydrofluoric Acid Burn of the Hand

    SciTech Connect

    Thomas, D. Jaeger, U.; Sagoschen, I.; Lamberti, C.; Wilhelm, K.

    2009-01-15

    Hydrofluoric acid (HF) is a colorless corrosive acid used in different industrial branches. Exposure to HF typically results from spills, and most often the hand or fingers are involved. Tissue damage through cutaneous HF exposure occurs through corrosive burns due to the free hydrogen ions and through skin penetration of the fluoride ions, causing a depletion of calcium in the deep tissue layers, ultimately leading to cell death and tissue necrosis. Treatment of HF burns consists of thoroughly flushing the exposed area with water and applying calcium gluconate gel to the skin. If topical treatment does not suffice, subcutaneous injections, as well as intravascular-both intravenous and intra-arterial-calcium gluconate therapy, have been advocated. We report for the first time a case of HF burn of the hand and digits associated with vasospasm. Pain and vasospasm were successfully treated by repeated intra-arterial calcium gluconate injection. We conclude that intra-arterial calcium gluconate injection is a successful and well-tolerated therapy for HF burn associated with Raynaud's syndrome. Intra-arterial injection allows for well-controlled delivery of therapy as well as assessment of the vascular status.

  4. Sulfate migration in a river affected by acid mine drainage from the Dabaoshan mining area, South China.

    PubMed

    Chen, Meiqin; Lu, Guining; Guo, Chuling; Yang, Chengfang; Wu, Jingxiong; Huang, Weilin; Yee, Nathan; Dang, Zhi

    2015-01-01

    Sulfate, a major component of acid mine drainage (AMD), its migration in an AMD-affected river which located at the Dabaoshan mine area of South China was investigated to pursue the remediation strategy. The existing factors of relatively low pH values of 2.8-3.9, high concentrations of SO4(2-) (∼1940 mg L(-1)) and Fe(3+) (∼112 mg L(-1)) facilitated the precipitation of schwertmannite (Fe8O8(OH)6SO4·nH2O) in the upstream river. Geochemical model calculations implied the river waters were supersaturated, creating the potential for precipitation of iron oxyhydroxides. These minerals evolved from schwertmannite to goethite with the increasing pH from 2.8 to 5.8 along the river. The concentration of heavy metals in river waters was great reduced as a result of precipitation effects. The large size of the exchangeable sulfate pool suggested that the sediments had a strong capacity to bind SO4(2-). The XRD results indicated that schwertmannite was the predominant form of sulfate-bearing mineral phases, which was likely to act as a major sulfate sink by incorporating water-borne sulfate into its internal structure and adsorbing it onto its surface. The small size of reduced sulfur pools and strong oxidative status in the surface sediments further showed that SO4(2-) shifting from water to sediment in form of sulfate reduction was not activated. In short, precipitation of sulfate-rich iron oxyhydroxides and subsequent SO4(2-) adsorption on these minerals as well as water dilution contributed to the attenuation of SO4(2-) along the river waters. PMID:25189685

  5. Sulfate migration in a river affected by acid mine drainage from the Dabaoshan mining area, South China.

    PubMed

    Chen, Meiqin; Lu, Guining; Guo, Chuling; Yang, Chengfang; Wu, Jingxiong; Huang, Weilin; Yee, Nathan; Dang, Zhi

    2015-01-01

    Sulfate, a major component of acid mine drainage (AMD), its migration in an AMD-affected river which located at the Dabaoshan mine area of South China was investigated to pursue the remediation strategy. The existing factors of relatively low pH values of 2.8-3.9, high concentrations of SO4(2-) (∼1940 mg L(-1)) and Fe(3+) (∼112 mg L(-1)) facilitated the precipitation of schwertmannite (Fe8O8(OH)6SO4·nH2O) in the upstream river. Geochemical model calculations implied the river waters were supersaturated, creating the potential for precipitation of iron oxyhydroxides. These minerals evolved from schwertmannite to goethite with the increasing pH from 2.8 to 5.8 along the river. The concentration of heavy metals in river waters was great reduced as a result of precipitation effects. The large size of the exchangeable sulfate pool suggested that the sediments had a strong capacity to bind SO4(2-). The XRD results indicated that schwertmannite was the predominant form of sulfate-bearing mineral phases, which was likely to act as a major sulfate sink by incorporating water-borne sulfate into its internal structure and adsorbing it onto its surface. The small size of reduced sulfur pools and strong oxidative status in the surface sediments further showed that SO4(2-) shifting from water to sediment in form of sulfate reduction was not activated. In short, precipitation of sulfate-rich iron oxyhydroxides and subsequent SO4(2-) adsorption on these minerals as well as water dilution contributed to the attenuation of SO4(2-) along the river waters.

  6. Rapid identification of triterpenoid sulfates and hydroxy fatty acids including two new constituents from Tydemania expeditionis by LC-MS

    PubMed Central

    Zhang, Jian-Long; Kubanek, Julia; Hay, Mark E.; Aalbersberg, William; Ye, Wen-Cai; Jiang, Ren-Wang

    2011-01-01

    Tydemania expeditionis Weber-van Bosse (Udoteaceae) is a weakly calcified green alga. In the present paper, liquid chromatography coupled with photodiode array detection and electrospray mass spectrometry was developed to identify the fingerprint components. A total of four triterpenoid sulfates and three hydroxy fatty acids in the ethyl acetate fraction of the crude extract were structurally characterized on the basis of retention time, online UV spectrum and mass fragmentation pattern. Furthermore, detailed LC-MS analysis revealed two new hydroxy fatty acids, which were then prepared and characterized by extensive NMR analyses. The proposed method provides a scientific and technical platform for the rapid identification of triterpenoid sulfates and hydroxy fatty acids in similar marine algae and terrestrial plants. PMID:21915955

  7. Exchangeable and secondary mineral reactive pools of aluminium in coastal lowland acid sulfate soils.

    PubMed

    Yvanes-Giuliani, Yliane A M; Waite, T David; Collins, Richard N

    2014-07-01

    The use of coastal floodplain sulfidic sediments for agricultural activities has resulted in the environmental degradation of many areas worldwide. The generation of acidity and transport of aluminium (Al) and other metals to adjacent aquatic systems are the main causes of adverse effects. Here, a five-step sequential extraction procedure (SEP) was applied to 30 coastal lowland acid sulfate soils (CLASS) from north-eastern New South Wales, Australia. This enabled quantification of the proportion of aluminium present in 'water-soluble', 'exchangeable', 'organically-complexed', 'reducible iron(III) (oxyhydr)oxide/hydroxysulfate-incorporated' and 'amorphous Al mineral' fractions. The first three extractions represented an average of 5% of 'aqua regia' extractable Al and their cumulative concentrations were extremely high, reaching up to 4000 mg·kg(-1). Comparison of Al concentrations in the final two extractions indicated that 'amorphous Al minerals' are quantitatively a much more important sink for the removal of aqueous Al derived from the acidic weathering of these soils than reducible Fe(III) minerals. Correlations were observed between soil pH, dissolved and total organic carbon (DOC and TOC) and Al concentrations in organic carbon-rich CLASS soil horizons. These results suggest that complexation of Al by dissolved organic matter significantly increases soluble Al concentrations at pH values >5.0. As such, present land management practices would benefit with redefinition of an 'optimal' soil from pH ≥5.5 to ~4.8 for the preservation of aquatic environments adjacent to organic-rich CLASS where Al is the sole or principle inorganic contaminant of concern. Furthermore, it was observed that currently-accepted standard procedures (i.e. 1 M KCl extraction) to measure exchangeable Al concentrations in these types of soils severely underestimate exchangeable Al and a more accurate representation may be obtained through the use of 0.2 M CuCl2.

  8. Methylsulfonylmethane and boswellic acids versus glucosamine sulfate in the treatment of knee arthritis: Randomized trial.

    PubMed

    Notarnicola, Angela; Maccagnano, Giuseppe; Moretti, Lorenzo; Pesce, Vito; Tafuri, Silvio; Fiore, Alessandra; Moretti, Biagio

    2016-03-01

    Until now glucosamine sulfate (GS) has been the most widely used supplement and has been shown to be efficacious in the treatment of osteoarthritis (OA). Methylsulfonylmethane (MSM) and boswellic acids (BA) are new effective supplements for the management of inflammation and joint degeneration, according to previous experimental studies. The aim of our study is to test the effectiveness of association of MSM and BA in comparison with GS in knee arthritis.In this prospective randomized clinical trial, MEBAGA (Methylsulfonylmethane and Boswellic Acids versus Glucosamine sulfate in the treatment of knee Arthritis), 120 participants affected by arthritis of the knee were randomly assigned to an experimental group (MB group) or a control group (GS group) treated for 60 days with 5 g of MSM and 7.2 mg of BA or with 1500 mg of GS daily, respectively. At the 2-month (T1) and 6-months (T2) follow-up , the efficacy of these two nutraceuticals was assessed using the visual analog pain scale (VAS) and the Lequesne Index (LI) for joint function, along with the use of anti-inflammatory drugs (non-steroidal anti-inflammatory drugs and anti-cyclooxygenase-2).The repeated measures ANOVA analysis shows that for VAS, LI, and the use of anti-inflammatory drugs scores there are improvements due to the time in the two groups (respectively, F=26.0; P<0.0001; F=4.15; P=0.02; F=3.38; P=0.04), with a tendency to better values for the MB group at T2.On the basis of these preliminary data, we could support the efficacy of the MSM in association with BA in the treatment of OA. These results are consistent with the anti-inflammatory and chondroprotective effects previously occurred in experimental studies. This new combination of integration (MSM and BS) has presented good results and satisfactory in comparison with GS, until now the cornerstone of the treatment of arthritis in according to guidelines. PMID:26684635

  9. Long-term competition between sulfate reducing and methanogenic bacteria in UASB reactors treating volatile fatty acids

    SciTech Connect

    Omil, F. |; Lens, P.; Visser, A.; Hulshoff Pol, L.W.; Lettinga, G.

    1998-03-20

    The competition between acetate utilizing methane-producing bacteria (MB) and sulfate-reducing bacteria (SRB) was studied in mesophilic (30 C) upflow anaerobic sludge bed (UASB) reactors treating volatile fatty acids and sulfate. The UASB reactors treated a VFA mixture (with an acetate:propionate:butyrate ratio of 5:3:2 on COD basis) or acetate as the sole substrate at different COD:sulfate ratios. The outcome of the competition was evaluated in terms of conversion rates and specific methanogenic and sulfidogenic activities. The COD:sulfate ratio was a key factor in the partitioning of acetate utilization between MB and SRB. In excess of sulfate, SRB became predominant over MB after prolonged reactor operation: 250 and 400 days were required to increase the amount of acetate used by SRB from 50 to 90% in the reactor treating, respectively, the VFA mixture or acetate as the sole substrate. The competition for acetate was further studied by dynamic simulations using a mathematical model based on the Monod kinetic parameters of acetate utilizing SRB and MB. The simulations confirmed the long term nature of the competition between these acetotrophs. A high reactor pH ({+-}8), a short solid retention time (<150 days), and the presence of a substantial SRB population in the inoculum may considerably reduce the time required for acetate-utilizing SRB to outcompete MB.

  10. Isotopic constraints on the role of hypohalous acids in sulfate aerosol formation in the remote marine boundary layer

    NASA Astrophysics Data System (ADS)

    Chen, Qianjie; Geng, Lei; Schmidt, Johan A.; Xie, Zhouqing; Kang, Hui; Dachs, Jordi; Cole-Dai, Jihong; Schauer, Andrew J.; Camp, Madeline G.; Alexander, Becky

    2016-09-01

    Sulfate is an important component of global atmospheric aerosol, and has partially compensated for greenhouse gas-induced warming during the industrial period. The magnitude of direct and indirect radiative forcing of aerosols since preindustrial times is a large uncertainty in climate models, which has been attributed largely to uncertainties in the preindustrial environment. Here, we report observations of the oxygen isotopic composition (Δ17O) of sulfate aerosol collected in the remote marine boundary layer (MBL) in spring and summer in order to evaluate sulfate production mechanisms in pristine-like environments. Model-aided analysis of the observations suggests that 33-50 % of sulfate in the MBL is formed via oxidation by hypohalous acids (HOX = HOBr + HOCl), a production mechanism typically excluded in large-scale models due to uncertainties in the reaction rates, which are due mainly to uncertainties in reactive halogen concentrations. Based on the estimated fraction of sulfate formed via HOX oxidation, we further estimate that daily-averaged HOX mixing ratios on the order of 0.01-0.1 parts per trillion (ppt = pmol/mol) in the remote MBL during spring and summer are sufficient to explain the observations.

  11. Effects of calcium channel blockers on gastric emptying and acid secretion of the rat in vivo.

    PubMed Central

    Brage, R.; Cortijo, J.; Esplugues, J.; Esplugues, J. V.; Martí-Bonmatí, E.; Rodriguez, C.

    1986-01-01

    Experiments were designed to evaluate the effects of three calcium channel blockers (verapamil, diltiazem and cinnarizine) on gastric emptying and secretion in the rat. Pretreatment with the calcium blockers delayed gastric emptying of phenol red in a dose-dependent manner. Verapamil was the most effective of the agents tested. Verapamil and diltiazem inhibited gastric acid secretion in the pylorus-ligated rat without affecting pepsin output. Cinnarizine was ineffective in this model. When the perfused lumen of the anaesthetized rat was used, verapamil was found to inhibit responses to carbachol or histamine more than those to pentagastrin. Further, we found a greater sensitivity to verapamil for basal compared with vagal-stimulated (2-deoxy-D-glucose) acid secretion. Neither diltiazem nor cinnarizine modified gastric acid secretion in this experimental model. These findings are discussed in relation to the role of extracellular calcium in gastric motility and secretion, and the existence of a regional and functional selectivity for calcium blockers is proposed. PMID:3814903

  12. Effects of calcium salts of acidic monomers on mineral induction of phosphoprotein immobilized to agarose beads.

    PubMed

    Ito, Shuichi; Iijima, Masahiro; Motai, Fumiko; Mizoguchi, Itaru; Saito, Takashi

    2012-10-01

    The aim of this study is to evaluate the mineralizing potential of acidic monomers and their calcium salts for mineralization, using an in vitro mineral induction model. Phosvitin (PV) was used as a model phosphoprotein in this study. PV was immobilized on agarose beads with divinyl sulfone. Five aliquots of agarose-immobilized PV, acidic monomers, and their calcium salts were incubated in mineralizing solution at various concentrations. The PV beads and acidic monomers were incubated at 37°C. Samples were taken at several time points during the incubation. Then, the agarose beads were analyzed for bound calcium by atomic absorption spectrometry. The mineral formed on the agarose beads was identified as an apatite by microarea X-ray diffraction. Additionally, the specimens were observed using scanning electron microscopy (SEM). Mineral induction time decreased with increasing solution saturation. 4-METCa salt [calcium salt of 4-methacryloxyethyl trimellitate (CMET)] significantly reduced the mineral induction time. Using these data, the interfacial tension for mineral induction of PV and CMET was determined to be 90.1 and 92.7 ergs/cm(2), respectively. The mineral induced in each specimen after incubation for 24 h was identified by its X-ray diffraction pattern as apatite. SEM observation showed that lath-shaped crystals were formed on the surfaces of the CMET. We conclude that CMET could play a role in dentin remineralization.

  13. Assay of calcium borogluconate veterinary medicines for calcium gluconate, boric acid, phosphorus, and magnesium by using inductively coupled plasma emission spectrometry.

    PubMed

    Lyons, D J; Spann, K P

    1985-01-01

    An inductively coupled plasma spectrometric method is described for the determination of 4 elements (Ca, B, P, and Mg) in calcium borogluconate veterinary medicines. Samples are diluted, acidified, and sprayed directly into the plasma. Reproducibility relative confidence intervals for a single sample assay are +/- 1.4% (calcium), +/- 1.8% (boron), +/- 2.6% (phosphorus), and +/- 1.4% (magnesium). The total element concentrations for each of 4 elements compared favorably with concentrations determined by alternative methods. Formulation estimates of levels of calcium gluconate, boric acid, phosphorus, and magnesium salts can be made from the analytical data.

  14. Assay of calcium borogluconate veterinary medicines for calcium gluconate, boric acid, phosphorus, and magnesium by using inductively coupled plasma emission spectrometry

    SciTech Connect

    Lyons, D.J.; Spann, K.P.

    1985-03-01

    An inductively coupled plasma spectrometric method is described for the determination of 4 elements (Ca, B, P, and Mg) in calcium borogluconate veterinary medicines. Samples are diluted, acidified, and sprayed directly into the plasma. Reproducibility relative confidence intervals for a single sample assay are +/- 1.4% (calcium), +/- 1.8% (boron), +/- 2.6% (phosphorus), and +/- 1.4% (magnesium). The total element concentrations for each of 4 elements compared favorably with concentrations determined by alternative methods. Formulation estimates of levels of calcium gluconate, boric acid, phosphorus, and magnesium salts can be made from the analytical data.

  15. Experimental and theoretical enthalpies of formation of glycine-based sulfate/bisulfate amino acid ionic liquids.

    PubMed

    Zhu, Jing-Fang; He, Ling; Zhang, Lei; Huang, Ming; Tao, Guo-Hong

    2012-01-12

    The experimental and theoretical enthalpies of formation of several structural-similar glycine-based sulfate/bisulfate amino acid ionic liquids including glycine sulfate (Gly(2)SO(4), 1), glycine bisulfate (GlyHSO(4), 2), N,N-dimethylglycine sulfate ([DMGly](2)SO(4), 3), N,N-dimethylglycine bisulfate ([DMGly]HSO(4), 4), N,N-dimethylglycine methyl ester sulfate ([DMGlyC(1)](2)SO(4), 5), N,N-dimethylglycine methyl ester bisulfate ([DMGlyC(1)]HSO(4), 6), N,N,N-trimethylglycine methyl ester sulfate ([TMGlyC(1)](2)SO(4), 7), and N,N,N-trimethylglycine methyl ester bisulfate ([TMGlyC(1)]HSO(4), 8) were studied. Their experimental enthalpies of formation were obtained from the corresponding energies of combustion determined by the bomb calorimetry method. The enthalpies of formation of these amino acid ionic liquids are in the range from -1406 kJ mol(-1) to -1128 kJ mol(-1). Systematic theoretical study on these amino acid ionic liquids were performed by quantum chemistry calculation using the Gaussian03 suite of programs. The geometric optimization and the frequency analyses are carried out using the B3LYP method with the 6-31+G** basis set. Their calculated enthalpies of formation were derived from the single point energies carried out with the HF/6-31+G**, B3LYP/6-31+G**, B3LYP/6-311++G**, and MP2/6-311++G** level of theory, respectively. The relevance of experimental and calculated enthalpies of formation was studied. The calculated enthalpies of formation are in good agreement with their experimental data in less than 3% error. PMID:22148242

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

    SciTech Connect

    Camilleri, Josette

    2011-01-15

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

  17. Effects of acid deposition on calcium nutrition and health of Southern Appalachian spruce fir forests

    SciTech Connect

    McLaughlin, S.B.; Wullschleger, S.; Stone, A.; Wimmer, R.; Joslin, J.D.

    1995-02-01

    The role of acid deposition in the health of spruce fir forests in the Southern Appalachian Mountains has been investigated by a wide variety of experimental approaches during the past 10 years. These studies have proceeded from initial dendroecological documentation of altered growth patterns of mature trees to increasingly more focused ecophysiological research on the causes and characteristics of changes in system function associated with increased acidic deposition. Field studies across gradients in deposition and soil chemistry have been located on four mountains spanning 85 km of latitude within the Southern Appalachians. The conclusion that calcium nutrition is an important component regulating health of red spruce in the Southern Appalachians and that acid deposition significantly reduces calcium availability in several ways has emerged as a consistent result from multiple lines or research. These have included analysis of trends in wood chemistry, soil solution chemistry, foliar nutrition, gas exchange physiology, root histochemistry, and controlled laboratory and field studies in which acid deposition and/or calcium nutrition has been manipulated and growth and nutritional status of saplings or mature red spruce trees measured. This earlier research has led us to investigate the broader implications and consequences of calcium deficiency for changing resistance of spruce-fir forests to natural stresses. Current research is exploring possible relationships between altered calcium nutrition and shifts in response of Fraser fir to insect attack by the balsam wooly adelgid. In addition, changes in wood ultrastructural properties in relation to altered wood chemistry is being examined to evaluate its possible role in canopy deterioration, under wind and ice stresses typical of high elevation forests.

  18. Treatment of Internal Hemorrhoids by Endoscopic Sclerotherapy with Aluminum Potassium Sulfate and Tannic Acid

    PubMed Central

    Tomiki, Yuichi; Ono, Seigo; Aoki, Jun; Takahashi, Rina; Ishiyama, Shun; Sugimoto, Kiichi; Yaginuma, Yukihiro; Kojima, Yutaka; Goto, Michitoshi; Okuzawa, Atsushi; Sakamoto, Kazuhiro

    2015-01-01

    Objective. A new sclerosing agent for hemorrhoids, aluminum potassium sulfate and tannic acid (ALTA), is attracting attention as a curative treatment for internal hemorrhoids without resection. The outcome and safety of ALTA sclerotherapy using an endoscope were investigated in the present study. Materials and Methods. Subjects comprised 83 internal hemorrhoid patients (61 males and 22 females). An endoscope was inserted and retroflexed in the rectum, and a 1st-step injection was applied to the upper parts of the hemorrhoids. The retroflexed scope was returned to the normal position, and 2nd–4th-step injections were applied to the middle and lower parts of the hemorrhoids under direct vision. The effects of endoscopic ALTA sclerotherapy were determined by evaluating the condition of the hemorrhoids using an anoscope and interviewing the patient 28 days after the treatment. Results. A cure, improvement, and failure were observed in 54 (65.1%), 27 (32.5%), and 2 (2.4%) patients, respectively, treated with ALTA. Complications developed in 4 patients (mild fever in 3 and hematuria in 1). Recurrence occurred in 9.6%. Conclusions. The results of the present study suggest that endoscopic ALTA has the potential to become a useful and minimally invasive approach for ALTA sclerotherapy. PMID:26246785

  19. Gallic acid suppresses inflammation in dextran sodium sulfate-induced colitis in mice: Possible mechanisms.

    PubMed

    Pandurangan, Ashok Kumar; Mohebali, Nooshin; Esa, Norhaizan Mohd; Looi, Chung Yeng; Ismail, Salmiah; Saadatdoust, Zeinab

    2015-10-01

    Inflammatory bowel diseases (IBD) encompass at least two forms of intestinal inflammation: Crohn's disease and ulcerative colitis (UC). Both conditions are chronic and inflammatory disorders in the gastrointestinal tract, with an increasing prevalence being associated with the industrialization of nations and in developing countries. Patients with these disorders are 10 to 20 times more likely to develop cancer of the colon. The aim of this study was to characterize the effects of a naturally occurring polyphenol, gallic acid (GA), in an experimental murine model of UC. A significant blunting of weight loss and clinical symptoms was observed in dextran sodium sulfate (DSS)-exposed, GA-treated mice compared with control mice. This effect was associated with a remarkable amelioration of the disruption of the colonic architecture, a significant reduction in colonic myeloperoxidase (MPO) activity, and a decrease in the expression of inflammatory mediators, such as inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, and pro-inflammatory cytokines. In addition, GA reduced the activation and nuclear accumulation of p-STAT3(Y705), preventing the degradation of the inhibitory protein IκB and inhibiting of the nuclear translocation of p65-NF-κB in colonic mucosa. These findings suggest that GA exerts potentially clinically useful anti-inflammatory effects mediated through the suppression of p65-NF-κB and IL-6/p-STAT3(Y705) activation.

  20. Silk fibroin/chondroitin sulfate/hyaluronic acid ternary scaffolds for dermal tissue reconstruction.

    PubMed

    Yan, Shuqin; Zhang, Qiang; Wang, Jiannan; Liu, Yu; Lu, Shenzhou; Li, Mingzhong; Kaplan, David L

    2013-06-01

    The fabrication of new dermal substitutes providing mechanical support and cellular cues is urgently needed in dermal reconstruction. Silk fibroin (SF)/chondroitin sulfate (CS)/hyaluronic acid (HA) ternary scaffolds (95-248μm in pore diameter, 88-93% in porosity) were prepared by freeze-drying. By the incorporation of CS and HA with the SF solution, the chemical potential and quantity of free water around ice crystals could be controlled to form smaller pores in the SF/CS/HA ternary scaffold main pores and improve scaffold equilibrium swelling. This feature offers benefits for cell adhesion, survival and proliferation. In vivo SF, SF/HA and SF/CS/HA (80/5/15) scaffolds as dermal equivalents were implanted onto dorsal full-thickness wounds of Sprague-Dawley rats to evaluate wound healing. Compared to SF and SF/HA scaffolds, the SF/CS/HA (80/5/15) scaffolds promoted dermis regeneration, related to improved angiogenesis and collagen deposition. Further, vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF) expression in the SF/CS/HA (80/5/15) groups were investigated by immunohistochemistry to assess the mechanisms involved in the stimulation of secretion of VEGF, PDGF and bFGF and accumulation of these growth factors related to accelerated wound process. These new three-dimensional ternary scaffolds offer potential for dermal tissue regeneration.

  1. Tough and elastic hydrogel of hyaluronic acid and chondroitin sulfate as potential cell scaffold materials.

    PubMed

    Ni, Yilu; Tang, Zhurong; Cao, Wanxu; Lin, Hai; Fan, Yujiang; Guo, Likun; Zhang, Xingdong

    2015-03-01

    Natural polysaccharides are extensively investigated as cell scaffold materials for cellular adhesion, proliferation, and differentiation due to their excellent biocompatibility, biodegradability, and biofunctions. However, their application is often severely limited by their mechanical behavior. In this study, a tough and elastic hydrogel scaffold was prepared with hyaluronic acid (HA) and chondroitin sulfate (CS). HA and CS were conjugated with tyramine (TA) and the degree of substitution (DS) was 10.7% and 11.3%, respectively, as calculated by (1)H NMR spectra. The hydrogel was prepared by mixing HA-TA and CS-TA in presence of H2O2 and HRP. The sectional morphology of hydrogels was observed by SEM, static and dynamic mechanical properties were analyzed by Shimadzu electromechanical testing machine and dynamic mechanical thermal analyzer Q800. All samples showed good ability to recover their appearances after deformation, the storage modulus (E') of hydrogels became higher as the testing frequency went up. Hydrogels also showed fatigue resistance to cyclic compression. Mesenchymal stem cells encapsulated in hydrogels showed good cell viability as detected by CLSM. This study suggests that the hydrogels have both good mechanical properties and biocompatibility, and may serve as model systems to explore mechanisms of deformation and energy dissipation or find some applications in tissue engineering. PMID:25445680

  2. Gallic acid attenuates dextran sulfate sodium-induced experimental colitis in BALB/c mice

    PubMed Central

    Pandurangan, Ashok Kumar; Mohebali, Nooshin; Norhaizan, Mohd Esa; Looi, Chung Yeng

    2015-01-01

    Gallic acid (GA) is a polyhydroxy phenolic compound that has been detected in various natural products, such as green tea, strawberries, grapes, bananas, and many other fruits. In inflammatory bowel disease, inflammation is promoted by oxidative stress. GA is a strong antioxidant; thus, we evaluated the cytoprotective and anti-inflammatory role of GA in a dextran sulfate sodium (DSS)-induced mouse colitis model. Experimental acute colitis was induced in male BALB/c mice by administering 2.5% DSS in the drinking water for 7 days. The disease activity index; colon weight/length ratio; histopathological analysis; mRNA expressions of IL-21 and IL-23; and protein expression of nuclear erythroid 2-related factor 2 (Nrf2) were compared between the control and experimental mice. The colonic content of malondialdehyde and the activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase activity were examined as parameters of the redox state. We determined that GA significantly attenuated the disease activity index and colon shortening, and reduced the histopathological evidence of injury. GA also significantly (P<0.05) reduced the expressions of IL-21 and IL-23. Furthermore, GA activates/upregulates the expression of Nrf2 and its downstream targets, including UDP-GT and NQO1, in DSS-induced mice. The findings of this study demonstrate the protective effect of GA on experimental colitis, which is probably due to an antioxidant nature of GA. PMID:26251571

  3. Improved detection of coastal acid sulfate soil hotspots through biomonitoring of metal(loid) accumulation in water lilies (Nymphaea capensis).

    PubMed

    Stroud, Jacqueline L; Collins, Richard N

    2014-07-15

    Anthropogenically disturbed coastal acid sulfate soils along the east coast of Australia, and worldwide, periodically result in the discharge of acid waters containing high concentrations of metals. Identifying priority sites (hotspots) within a catchment for acid sulfate soil remediation activities typically involves long-term monitoring of drainwater chemistry, including the capture of data on unpredictable rain-induced groundwater discharge events. To improve upon this monitoring approach, this study investigated using the water lily (Nymphaea capensis) as a biomonitor of drainage waters to identify hotspots in three acid sulfate soil impacted catchments (83 km(2)) in north-eastern New South Wales, Australia. In one catchment where the location of hotspots was known, water lily lamina concentrations of a suite of metal(loid)s were significantly (p<0.05) higher than plants collected from an unpolluted 'reference' drainage channel, thus validating the concept of using this species as a biomonitor. A catchment-scale water lily sampling program undertaken in catchments with unidentified hotspots revealed within catchment variation of plant metal concentrations up to 70-fold. High resolution maps produced from these results, therefore, provided strong evidence for the location of potential hotspots which were confirmed with measurements of drainwater chemistry during rain-induced groundwater discharge events. Median catchment lily accumulation was ca. 160 mg Al kg(-1) and 1,300 mg Fe kg(-1), with hotspots containing up to 6- and 10-fold higher Al and Fe concentrations. These findings suggest that biomonitoring with N. capensis can be an important tool to rapidly identify priority sites for remediation in acid sulfate soil impacted landscapes.

  4. Improved detection of coastal acid sulfate soil hotspots through biomonitoring of metal(loid) accumulation in water lilies (Nymphaea capensis).

    PubMed

    Stroud, Jacqueline L; Collins, Richard N

    2014-07-15

    Anthropogenically disturbed coastal acid sulfate soils along the east coast of Australia, and worldwide, periodically result in the discharge of acid waters containing high concentrations of metals. Identifying priority sites (hotspots) within a catchment for acid sulfate soil remediation activities typically involves long-term monitoring of drainwater chemistry, including the capture of data on unpredictable rain-induced groundwater discharge events. To improve upon this monitoring approach, this study investigated using the water lily (Nymphaea capensis) as a biomonitor of drainage waters to identify hotspots in three acid sulfate soil impacted catchments (83 km(2)) in north-eastern New South Wales, Australia. In one catchment where the location of hotspots was known, water lily lamina concentrations of a suite of metal(loid)s were significantly (p<0.05) higher than plants collected from an unpolluted 'reference' drainage channel, thus validating the concept of using this species as a biomonitor. A catchment-scale water lily sampling program undertaken in catchments with unidentified hotspots revealed within catchment variation of plant metal concentrations up to 70-fold. High resolution maps produced from these results, therefore, provided strong evidence for the location of potential hotspots which were confirmed with measurements of drainwater chemistry during rain-induced groundwater discharge events. Median catchment lily accumulation was ca. 160 mg Al kg(-1) and 1,300 mg Fe kg(-1), with hotspots containing up to 6- and 10-fold higher Al and Fe concentrations. These findings suggest that biomonitoring with N. capensis can be an important tool to rapidly identify priority sites for remediation in acid sulfate soil impacted landscapes. PMID:24805963

  5. 87Sr/86Sr in recent accumulations of calcium sulfate on landscapes of hyperarid settings: A bimodal altitudinal dependence for northern Chile (19.5°S-21.5°S)

    NASA Astrophysics Data System (ADS)

    Cosentino, N. J.; Jordan, T. E.; Derry, L. A.; Morgan, J. P.

    2015-12-01

    An elevation-dependent relationship of the 87Sr/86Sr ratio of Holocene surface accumulations of sulfate salts is demonstrated for a continental margin hyperarid setting. In the Atacama Desert of northern Chile, gypsum and anhydrite of multiple origins exist widely on superficial materials that originated during the last 10,000 years. An important source of calcium sulfate is from offshore-generated stratocumulus clouds that are advected onto the continent, where they generate fog that transfers water droplets to the ground surface which, upon evaporation, leaves calcium sulfate crystals. Meteorological measurements of the cloud base and top altitudes average ˜400 m and ˜1100 m above sea level (masl), respectively. The seawater ratio of 87Sr/86Sr (0.70917) is distinctively higher than that reported for weathered mean Andean rock (less than 0.70750). Samples of 28 modern surface salt accumulations for locations between 200 and 2950 masl and between ˜19°30' and ˜21°30'S verify that 87Sr/86Sr varies as a function of site altitude. Sites below 1075 masl and above 225 masl display calcium sulfate 87Sr/86Sr of mean value 0.70807 ± 0.00004, while the ratio outside this altitudinal domain is 0.70746 ± 0.00010. Thus, the 87Sr/86Sr ratio of Holocene salt accumulations differentiates two altitudinal domains.

  6. Filler modification for papermaking with starch/oleic acid complexes with the aid of calcium ions.

    PubMed

    Huang, Xiujie; Shen, Jing; Qian, Xueren

    2013-10-15

    To mitigate the negative effect of filler addition on paper strength and improve filler retention, filler modification with hydrogen bonding polymers (e.g., starch) or their composites is an interesting research topic. Differing from previous reports, the concept related to the deposition of starch/oleic acid complexes on precipitated calcium carbonate (PCC) with the aid of calcium ions was demonstrated. The introduction of calcium ions resulted in effective starch deposition. As a result of filler modification, filler retention and the tensile strength of the filled paper were simultaneously improved essentially due to the aggregation of PCC particles in filler modification process as well as improved filler bondability. The concept demonstrated in this brief study may provide an alternative approach to filler bondability enhancement for improved papermaking performances.

  7. Lubricant and Bactericidal Properties of Calcium Salts of Fatty Acids: Effect of Degree of Unsaturation.

    PubMed

    Yamamoto, Yoshiaki; Kijima, Tatsuro; Morikawa, Toshiya; Nonomura, Yoshimune

    2015-01-01

    Fatty acids containing a C18 alkyl chain such as stearic acid (C18:0 fatty acid), oleic acid (C18:1 fatty acid) and linoleic acid (C18:2 fatty acid) are common emulsifiers in skin-care products and cosmetics and are also used in skin cleansers. In this study, we prepared calcium salts (Ca salts) of the above fatty acids to determine the effect of the degree of unsaturation of the alkyl chain. Scanning electron microscopy images and X-ray diffraction patterns show that C18:0 and C18:1 fatty acid Ca salts are plate-shaped, lamellar-crystalline powder, while C18:2 fatty acid Ca salt is amorphous powder. Therefore, C18:2 fatty acid Ca salt exhibits a lower lubrication ability than do C18:0 and C18:1 fatty acid Ca salts. In addition, the bactericidal ability against Staphylococcus aureus, Staphylococcus epidermidis and Propionibacterium acnes improved with increasing degree of unsaturation. These findings suggest that Ca salts of unsaturated fatty acids have potential applications in cleansing and cosmetic products.

  8. Degradation of dissolved organic monomers and short-chain fatty acids in sandy marine sediment by fermentation and sulfate reduction

    NASA Astrophysics Data System (ADS)

    Valdemarsen, Thomas; Kristensen, Erik

    2010-03-01

    The decay of a wide range of organic monomers (short-chain volatile fatty acids (VFA's), amino acids, glucose and a pyrimidine) was studied in marine sediments using experimental plug flow-through reactors. The reactions were followed in the presence and absence of 10 mM SO 42-. Degradation stoichiometry of individual monomers (inflow concentration of 6 mM organic C) was traced by measuring organic (VFA's, amino acids) and inorganic (CO 2, NH 4+, SO 42-) compounds in the outflow. Fermentation of amino acids was efficient and complete during passage through anoxic sediment reactors. Aliphatic amino acids (alanine, serine and glutamate) were primarily recovered as CO 2 (24-34%), formate (3-22%) and acetate (41-83%), whereas only ˜1/3 of the aromatic amino acid (tyrosine) was recovered as CO 2 (13%) and acetate (20%). Fermentation of glucose and cytosine was also efficient (78-86%) with CO 2 (30-35%), formate (3%) and acetate (28-33%) as the primary products. Fermentation of VFA's (acetate, propionate and butyrate), on the other hand, appeared to be product inhibited. The presence of SO 42- markedly stimulated VFA degradation (29-45% efficiency), and these compounds were recovered as CO 2 (17% for butyrate to 100% for acetate) and acetate (51% and 82% for propionate and butyrate, respectively). When reaction stoichiometry during fermentation is compared with compound depletion during sulfate reduction, the higher proportion CO 2 recovery is consistent with lower acetate and formate accumulation. Our results therefore suggest that fermentation reactions mediate the initial degradation of added organic compounds, even during active sulfate reduction. Fermentative degradation stoichiometry also suggested significant H 2 production, and >50% of sulfate reduction appeared to be fuelled by H 2. Furthermore, our results suggest that fermentation was the primary deamination step during degradation of the amino acids and cytosine.

  9. Identification of sulfated oligosialic acid units in the O-linked glycan of the sea urchin egg receptor for sperm.

    PubMed

    Kitazume-Kawaguchi, S; Inoue, S; Inoue, Y; Lennarz, W J

    1997-04-15

    The Strongylocentrotus purpuratus sea urchin egg receptor for sperm is a cell surface glycoprotein with a molecular mass of 350 kDa. Recent studies indicate that the sulfated O-linked glycans isolated from the receptor bind to acrosome-reacted sperm. The purified receptor was analyzed with respect to amino acid and carbohydrate content and shown to be composed of 70% carbohydrate by weight. Compositional analysis indicated that both N- and O-linked oligosaccharide chains were present. After peptide:N-glycanase treatment of the receptor to remove most of the N-linked glycan chains, the majority of the sialic acid residues remained associated with the receptor and were shown by several types of experiments to be composed of sulfated oligosialic acid units attached to the O-linked glycan chains of the receptor. Chemical and physical studies on oligosialic chains discovered earlier in the Pronase-generated glycopeptide fraction isolated from the egg cell surface complex of another species of sea urchin, Hemicentrotus pulcherrimus, established that these molecules had the structure: (SO(4)-)-9Neu5Gc alpha2(-->5-O(glycolyl)Neu5Gc alpha2-->)n. Based on comparative and analytical studies, it was concluded that this sulfated oligosaccharide is a component of a GalNAc-containing chain that is O-linked to the polypeptide chain of the sea urchin egg receptor for sperm. Using a competitive inhibition of fertilization bioassay it was shown that the sulfated oligosialic acid chains derived from the S. purpuratus egg cell surface complex inhibited fertilization; the nonsulfated form of this oligosialic chain had little inhibitory activity.

  10. Use of magnetophoresis of glutamic acid and magnesium sulfate in the rehabilitation of children with cerebral palsy.

    PubMed

    Gurova, N Yu; Babina, L M

    2008-11-01

    We report here our studies on the clinical efficacy of courses of magnetophoresis of glutamic acid and magnesium sulfate in the complex rehabilitation treatment of preschool children with spastic types of cerebral palsy. Clinical-neurophysiological investigations were performed in 40 children aged 1-7 years. Treatment was significantly more effective when use of running pulsed magnetic fields was combined with medicinal agents as compared with magnetotherapy using the same regime. PMID:18975105

  11. Arachidonic and eicosapentaenoic acid metabolism in bovine neutrophils and platelets: effect of calcium ionophore

    SciTech Connect

    Taylor, S.M.; Laegreid, W.W.; Heidel, J.R.; Straub, K.M.; Liggitt, H.D.; Silflow, R.M.; Breeze, R.G.; Leid, R.W.

    1987-09-01

    Substitution of dietary fatty acids has potential for altering the inflammatory response. The purpose of the present study was to define the metabolites of arachidonic acid (AA) and eicosapentaenoic acid (EPA) secreted by bovine peripheral blood neutrophils and platelets. High performance liquid chromatography was used to characterize cyclooxygenase and lipoxygenase metabolites secreted in response to the calcium ionophore A23187. Cells were prelabelled with /sup 3/H-AA or /sup 3/H-EPA prior to challenge with the calcium ionophore. Bovine neutrophils secreted leukotriene B4 (LTB4) and 5-hydroxyeicosatetraenoic acid (5-HETE) as the major metabolites of AA, as well as the corresponding leukotriene B5 (LTB5) and 5-hydroxyeicosapentaenoic acid (5-HEPE) metabolites of EPA. Peptidoleukotrienes derived from /sup 3/H-AA or /sup 3/H-EPA were not detected under these conditions. The major tritiated metabolites secreted from bovine platelets were: thromboxane A2, measured as the stable metabolite thromboxane B2 (TXB2); hydroxyheptadecatrienoic acid (HHT) and 12-HETE derived from /sup 3/H-AA; and the omega-3 analogs TXB3 and 12-HEPE, derived from /sup 3/H-EPA. Preferred substrate specificities existed amongst the AA- and EPA-derived metabolites for the intermediary enzymes involved in the arachidonic acid cascade. These findings support the hypothesis that substitution of membrane-bound AA by EPA has potential for modulation of the host inflammatory response following cellular phospholipid mobilization.

  12. Carbonate-containing apatite (CAP) synthesis under moderate conditions starting from calcium carbonate and orthophosphoric acid.

    PubMed

    Pham Minh, Doan; Tran, Ngoc Dung; Nzihou, Ange; Sharrock, Patrick

    2013-07-01

    The synthesis of carbonate-containing apatite (CAP) from calcium carbonate and orthophosphoric acid under moderate conditions was investigated. In all cases, complete precipitation of orthophosphate species was observed. The reaction temperature influenced strongly the decomposition of calcium carbonate and therefore the composition of formed products. The reaction temperature of 80 °C was found to be effective for the complete decomposition of calcium carbonate particles after 48 h of reaction. Infra-red spectroscopy (IR), nuclear magnetic resonance (NMR), thermogravimetry/mass spectroscopy (TG-MS) coupling, and X-ray diffraction (XRD) characterizations allowed the identification of the composition of formed products. By increasing the reaction temperature from 20 °C to 80 °C, the content of A-type CAP increased and that of B-type CAP decreased, according to the favorable effect of temperature on the formation of A-type CAP. The total amount of carbonate content incorporated in CAP's structure, which was determined by TG-MS analysis, increased with the reaction temperature and reached up to 4.1% at 80 °C. At this temperature, the solid product was mainly composed of apatitic components and showed the typical flat-needle-like structure of CAP particles obtained in hydrothermal conditions. These results show an interesting one-step synthesis of CAP from calcium carbonate and orthophosphoric acid as low cost but high purity starting materials.

  13. Undersulfation of cartilage proteoglycans ex vivo and increased contribution of amino acid sulfur to sulfation in vitro in McAlister dysplasia/atelosteogenesis type 2.

    PubMed

    Rossi, A; Bonaventure, J; Delezoide, A L; Superti-Furga, A; Cetta, G

    1997-09-15

    Mutations in the diastrophic dysplasia sulfate transporter gene cause a family of chondrodysplasias including, in order of increasing severity, diastrophic dysplasia, atelosteogenesis type 2 and achondrogenesis type 1B. McAlister dysplasia is a lethal chondrodysplasia considered on the basis of minor radiographic features to be a disorder different from atelosteogenesis type 2. Here, we demonstrate that McAlister dysplasia arises from mutations in the diastrophic dysplasia sulfate transporter gene and that this disorder essentially coincides on molecular and biochemical grounds with atelosteogenesis type 2. The fetus affected by McAlister dysplasia we have studied is a compound heterozygote for mutations leading to R279W and N425D substitutions in the diastrophic dysplasia sulfate transporter. Proteoglycan sulfation was studied in epiphyseal cartilage and in chondrocyte cultures of the patient by high performance liquid chromatography of chondrotinase digested proteoglycans; a high amount of non-sulfated disaccharide was observed as a consequence of the alteration of the transporter function caused by the mutations. However, sulfated disaccharides were detectable even if in low amounts, both in cultured cells and tissue. Functional impairment of the sulfate transporter was demonstrated in vitro by reduced incorporation of [35S]sulfate relative to [3H]glucosamine in proteoglycans synthesized by chondrocytes and by sulfate-uptake assays in fibroblasts. Parallel in vitro studies in a patient with achondrogenesis 1B indicated that the severity of the clinical phenotype seems to be correlated to the residual activity of the sulfate transporter. The capacity of fibroblasts to use cysteine as an alternative source of sulfate was evaluated by double-labeling experiments. Relative incorporation of [35S]cysteine-derived sulfate in the glycosaminoglycan chains was increased in the patient's cells, indicating that, in vitro, the catabolism of sulfur-containing amino acids can

  14. Effects of precursor concentration and acidic sulfate in aqueous glyoxal-OH radical oxidation and implications for secondary organic aerosol.

    PubMed

    Tan, Yi; Perri, Mark J; Seitzinger, Sybil P; Turpin, Barbara J

    2009-11-01

    Previous experiments demonstrated that aqueous OH radical oxidation of glyoxal yields low-volatility compounds. When this chemistry takes place in clouds and fogs, followed by droplet evaporation (or if it occurs in aerosol water), the products are expected to remain partially in the particle phase, forming secondary organic aerosol (SOA). Acidic sulfate exists ubiquitously in atmospheric water and has been shown to enhance SOA formation through aerosol phase reactions. In this work, we investigate how starting concentrations of glyoxal (30-3000 microM) and the presence of acidic sulfate (0-840 microM) affect product formation in the aqueous reaction between glyoxal and OH radical. The oxalic acid yield decreased with increasing precursor concentrations, and the presence of sulfuric acid did not alter oxalic acid concentrations significantly. A dilute aqueous chemistry model successfully reproduced oxalic acid concentrations, when the experiment was performed at cloud-relevant concentrations (glyoxal <300 microM), but predictions deviated from measurements at increasing concentrations. Results elucidate similarities and differences in aqueous glyoxal chemistry in clouds and in wet aerosols. They validate for the first time the accuracy of model predictions at cloud-relevant concentrations. These results suggest that cloud processing of glyoxal could be an important source of SOA. PMID:19924930

  15. Effects of precursor concentration and acidic sulfate in aqueous glyoxal-OH radical oxidation and implications for secondary organic aerosol.

    PubMed

    Tan, Yi; Perri, Mark J; Seitzinger, Sybil P; Turpin, Barbara J

    2009-11-01

    Previous experiments demonstrated that aqueous OH radical oxidation of glyoxal yields low-volatility compounds. When this chemistry takes place in clouds and fogs, followed by droplet evaporation (or if it occurs in aerosol water), the products are expected to remain partially in the particle phase, forming secondary organic aerosol (SOA). Acidic sulfate exists ubiquitously in atmospheric water and has been shown to enhance SOA formation through aerosol phase reactions. In this work, we investigate how starting concentrations of glyoxal (30-3000 microM) and the presence of acidic sulfate (0-840 microM) affect product formation in the aqueous reaction between glyoxal and OH radical. The oxalic acid yield decreased with increasing precursor concentrations, and the presence of sulfuric acid did not alter oxalic acid concentrations significantly. A dilute aqueous chemistry model successfully reproduced oxalic acid concentrations, when the experiment was performed at cloud-relevant concentrations (glyoxal <300 microM), but predictions deviated from measurements at increasing concentrations. Results elucidate similarities and differences in aqueous glyoxal chemistry in clouds and in wet aerosols. They validate for the first time the accuracy of model predictions at cloud-relevant concentrations. These results suggest that cloud processing of glyoxal could be an important source of SOA.

  16. Arachidonic acid-induced mobilization of calcium in human neutrophils: evidence for a multicomponent mechanism of action.

    PubMed Central

    Naccache, P. H.; McColl, S. R.; Caon, A. C.; Borgeat, P.

    1989-01-01

    1. The mechanism(s) involved in the mobilization of calcium induced by arachidonic acid in human neutrophils was investigated. 2. The addition of arachidonic acid to a suspension of human neutrophils led to a time- and concentration-dependent mobilization of calcium which was the result of two separate and experimentally differentiable processes. The latter consisted of a rapid and transient phase followed by a slower and more sustained response. 3. The initial phase of calcium mobilization elicited by arachidonic acid was decreased in the presence of EGTA, inhibited by pertussis toxin as well as by nordihydroguaiaretic acid (NDGA), and diminished following a pre-incubation with leukotriene B4, but not platelet-activating factor. 4. The characteristics of the first phase of the mobilization of calcium were consistent with an interaction of the fatty acid with the leukotriene B4 receptors, either directly or indirectly following the synthesis of leukotriene B4, as well as with a release of internal calcium. 5. The second, slower and more sustained phase of calcium mobilization was more apparent at high concentrations (greater than or equal to 8-16 microM) of arachidonic acid, and was relatively insensitive to pertussis toxin, EGTA or NDGA. 6. The characteristics of the 'slow' phase of calcium mobilization by arachidonic acid are consistent with its being associated primarily with a release of calcium from internal storage pools. 7. The data presented indicate that the mechanism of mobilization of calcium by arachidonic acid in human neutrophils is complex and involves specific activation pathways employed, in part at least, by other neutrophil agonists.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2547474

  17. Abscisic acid induces a cytosolic calcium decrease in barley aleurone protoplasts.

    PubMed

    Wang, M; Van Duijn, B; Schram, A W

    1991-01-14

    Cytosolic calcium concentrations (Cai) of barley aleurone protoplasts after stimulation with the plant hormone abscisic acid (ABA) were measured by using the calcium-sensitive fluorescent dye Indo-1. The measured basal Cai is about 200 nM. Stimulation with ABA induces a strong dose-dependent decrease in Cai to a minimal value of about 50 nM. This decrease occurs within 5 s. The Ca2+ antagonists La3+ and Cd2+ inhibit the ABA-induced Cai decrease in a dose-dependent manner, while the Ca2+ channel blockers verapamil and nifedipine give no inhibition. The induction of Cai decrease by ABA is consistent with activation of the plasma membrane Ca2(+)-ATPase by ABA. The possible role of this ABA-induced Cai decrease in ABA signal transduction and in counteracting the effects of gibberellic acid are discussed.

  18. The kinetics of sulfation of calcium oxide. [Quarterly] project status report, June 1, 1989--August 31, 1989

    SciTech Connect

    Sarofim, A.F.; Longwell, J.P.

    1989-12-31

    Studies of the sulfation rate behavior show an initial fast rate followed by a rate decrease. This behavior has generally been interpreted as product layer diffusion limitations taking over after an initial kinetic rate regime. Many investigators tried to model this observed rate change, more or less successfully. No agreement has been reached, however, as to the value of the product layer diffusivity. In this work we want to investigate the mechanism of this process. During the last quarter, most attention has been paid to analyzing the results obtained earlier. In the light of some unexpected results, we returned to the most fundamental question: what is the rate-limiting mechanism? It appeared that whatever the mechanism is, no rate ``constant`` could be used, since the rate is a function of the product layer composition, which changes during the reaction. When comparing the results obtained with different samples, however, it appeared that the best correlation was found if one assumes the limiting rate to occur at the CaSO{sub 4} interphase. This point of view has never been presented before and requires therefore a more attentive analysis.

  19. Biologically-induced precipitation of sphalerite-wurtzite nanoparticles by sulfate-reducing bacteria: implications for acid mine drainage treatment.

    PubMed

    Castillo, Julio; Pérez-López, Rafael; Caraballo, Manuel A; Nieto, José M; Martins, Mónica; Costa, M Clara; Olías, Manuel; Cerón, Juan C; Tucoulou, Rémi

    2012-04-15

    Several experiments were conducted to evaluate zinc-tolerance of sulfate-reducing bacteria (SRB) obtained from three environmental samples, two inocula from sulfide-mining districts and another inoculum from a wastewater treatment plant. The populations of SRB resisted zinc concentrations of 260 mg/L for 42 days in a sulfate-rich medium. During the experiments, sulfate was reduced to sulfide and concentrations in solution decreased. Zinc concentrations also decreased from 260 mg/L to values below detection limit. Both decreases were consistent with the precipitation of newly-formed sphalerite and wurtzite, two polymorphs of ZnS, forming <2.5-μm-diameter spherical aggregates identified by microscopy and synchrotron-μ-XRD. Sulfate and zinc are present in high concentrations in acid mine drainage (AMD) even after passive treatments based on limestone dissolution. The implementation of a SRB-based zinc removal step in these systems could completely reduce the mobility of all metals, which would improve the quality of stream sediments, water and soils in AMD-affected landscapes.

  20. Biologically-induced precipitation of sphalerite-wurtzite nanoparticles by sulfate-reducing bacteria: implications for acid mine drainage treatment.

    PubMed

    Castillo, Julio; Pérez-López, Rafael; Caraballo, Manuel A; Nieto, José M; Martins, Mónica; Costa, M Clara; Olías, Manuel; Cerón, Juan C; Tucoulou, Rémi

    2012-04-15

    Several experiments were conducted to evaluate zinc-tolerance of sulfate-reducing bacteria (SRB) obtained from three environmental samples, two inocula from sulfide-mining districts and another inoculum from a wastewater treatment plant. The populations of SRB resisted zinc concentrations of 260 mg/L for 42 days in a sulfate-rich medium. During the experiments, sulfate was reduced to sulfide and concentrations in solution decreased. Zinc concentrations also decreased from 260 mg/L to values below detection limit. Both decreases were consistent with the precipitation of newly-formed sphalerite and wurtzite, two polymorphs of ZnS, forming <2.5-μm-diameter spherical aggregates identified by microscopy and synchrotron-μ-XRD. Sulfate and zinc are present in high concentrations in acid mine drainage (AMD) even after passive treatments based on limestone dissolution. The implementation of a SRB-based zinc removal step in these systems could completely reduce the mobility of all metals, which would improve the quality of stream sediments, water and soils in AMD-affected landscapes. PMID:22414495

  1. Sulfate adsorption on goethite

    SciTech Connect

    Rietra, R.P.J.J.; Hiemstra, T.; Riemsdijk, W.H. van

    1999-10-15

    Recent spectroscopic work has suggested that only one surface species of sulfate is dominant on hematite. Sulfate is therefore a very suitable anion to test and develop adsorption models for variable charge minerals. The authors have studied sulfate adsorption on goethite covering a large range of sulfate concentrations, surface coverages, pH values, and electrolyte concentrations. Four different techniques were used to cover the entire range of conditions. For characterization at low sulfate concentrations, below the detection limit of sulfate with ICP-AES, the authors used proton-sulfate titrations at constant pH. Adsorption isotherms were studied for the intermediate sulfate concentration range. Acid-base titrations in sodium sulfate and electromobility were used for high sulfate concentrations. All the data can be modeled with one adsorbed species if it is assumed that the charge of adsorbed sulfate is spatially distributed in the interface. The charge distribution of sulfate follows directly from modeling the proton-sulfate adsorption stoichoimemtry sine this stoichiometry is independent of the intrinsic affinity constant of sulfate. The charge distribution can be related to the structure of the surface complex by use of the Pauling bond valence concept and is in accordance with the microscopic structure found by spectroscopy. The intrinsic affinity constant follows from the other measurements. Modeling of the proton-ion stoichoimetry with the commonly used 2-pK models, where adsorbed ions are treated as point charges, is possible only if at least two surface species for sulfate are used.

  2. [Microbial geochemical calcium cycle].

    PubMed

    Zavarzin, G A

    2002-01-01

    The participation of microorganisms in the geochemical calcium cycle is the most important factor maintaining neutral conditions on the Earth. This cycle has profound influence on the fate of inorganic carbon, and, thereby, on the removal of CO2 from the atmosphere. The major part of calcium deposits was formed in the Precambrian, when prokaryotic biosphere predominated. After that, calcium recycling based on biogenic deposition by skeletal organisms became the main process. Among prokaryotes, only a few representatives, e.g., cyanobacteria, exhibit a special calcium function. The geochemical calcium cycle is made possible by the universal features of bacteria involved in biologically mediated reactions and is determined by the activities of microbial communities. In the prokaryotic system, the calcium cycle begins with the leaching of igneous rock predominantly through the action of the community of organotrophic organisms. The release of carbon dioxide to the soil air by organotrophic aerobes leads to leaching with carbonic acid and soda salinization. Under anoxic conditions, of major importance is the organic acid production by primary anaerobes (fermentative microorganisms). Calcium carbonate is precipitated by secondary anaerobes (sulfate reducers) and to a smaller degree by methanogens. The role of the cyanobacterial community in carbonate deposition is exposed by stromatolites, which are the most common organo-sedimentary Precambrian structures. Deposition of carbonates in cyanobacterial mats as a consequence of photoassimilation of CO2 does not appear to be a significant process. It is argued that carbonates were deposited at the boundary between the "soda continent", which emerged as a result of subaerial leaching with carbonic acid, and the ocean containing Ca2+. Such ecotones provided favorable conditions for the development of the benthic cyanobacterial community, which was a precursor of stromatolites.

  3. Hyaluronic acid/chondroitin sulfate-based hydrogel prepared by gamma irradiation technique.

    PubMed

    Zhao, Linlin; Gwon, Hui-Jeong; Lim, Youn-Mook; Nho, Young-Chang; Kim, So Yeon

    2014-02-15

    Gamma-ray irradiation of novel hydrogels was used to develop a biocompatible hydrogel system for skin tissue engineering. These novel hydrogels are composed of natural polymers including hyaluronic acid (HA) and chondroitin sulfate (CS), and the synthetic polymer, poly(vinyl alcohol) (PVA). The γ-ray irradiation method has advantages, such as relatively simple manipulation without need of any extra reagents for polymerization and cross-linking. We synthesized HA and CS derivatives with polymerizable residues. The HA/CS/PVA hydrogels with various compositions were prepared by using γ-ray irradiation technique and their physicochemical properties were investigated to evaluate the feasibility of their use as artificial skin substitutes. HA/CS/PVA hydrogels showed an 85-88% degree of gelation under 15 kGy radiation. All HA/CS/PVA hydrogels exhibited more than 90% water content and reached an equilibrium swelling state within 24h. Hydrogels with higher concentrations of hyaluronidase solution and HA/CS content had proportionally higher enzymatic degradation rates. The drug release behaviors from HA/CS/PVA hydrogels were influenced by the composition of the hydrogel and drug properties. Exposure of human keratinocyte (HaCaT) culture to the extracts of HA/CS/PVA hydrogels did not significantly affect the cell viability. All HaCaT cell cultures exposed to the extracts of HA/CS/PVA hydrogels exhibited greater than 92% cell viability. The HaCaT growth in HA/CS/PVA hydrogels gradually increased as a function of culture time. After 7 days, the HaCaT cells in all HA/CA/PVA hydrogels exhibited more than 80% viability compared to the control group HaCaT culture on a culture plate. PMID:24507324

  4. Metal and acidity fluxes controlled by precipitation/dissolution cycles of sulfate salts in an anthropogenic mine aquifer

    NASA Astrophysics Data System (ADS)

    Cánovas, C. R.; Macías, F.; Pérez-López, R.

    2016-05-01

    Underground mine drainages are extremely difficult to study due to the lack of information about the flow path and source proximity in relation to the outflow adit. Geochemical processes controlling metals and acidity fluxes in a complex anthropogenic mine aquifer in SW Spain during the dry and rainy season were investigated by geochemical and statistical tools. High concentrations of acidity, sulfate, metals and metalloids (e.g. Fe, Cu, Zn, As, Cd, Ni, Co) were observed due to intense sulfide oxidation processes. The high residence time inside the anthropogenic aquifer, around 40 days, caused the release of significant quantities of metals linked to host rocks (e.g. Al, Ca, Ge, Li, Mg, REE). The most outstanding characteristic of the acid mine drainage (AMD) outflows is the existence of higher Fe/SO4 molar ratios than those theoretical of pyrite (0.50) during most of the monitored period, due to a fire which occurred in 1949 and remained active for decades. Permanent and temporal retention mechanisms of acidity and metals were observed in the galleries. Once released from sulfide oxidation, Pb and As are sorbed on Fe oxyhydroxysulfate or precipitated as low solubility minerals (i.e. anglesite) inside the galleries. The precipitation of evaporitic sulfate salts during the dry season and the subsequent re-dissolution after rainfall control the fluxes of acidity and main metals (i.e. Fe, Mg, Al) from this anthropogenic aquifer. Some elements, such as Cd, Cu, Ni, REE and Zn, are retained in highly soluble sulfate salts while other elements, such as Ge, Pb and Sc, have a lower response to washout processes due to its incorporation in less soluble sulfate salts. In this way, metal concentration during the washout processes would be controlled by the proportion and solubility of each type of evaporitic sulfate salt stored during the dry season. The recovery of metals of economic interest contained in the AMD could help to self-finance the remediation of these waters in

  5. Metal and acidity fluxes controlled by precipitation/dissolution cycles of sulfate salts in an anthropogenic mine aquifer.

    PubMed

    Cánovas, C R; Macías, F; Pérez-López, R

    2016-05-01

    Underground mine drainages are extremely difficult to study due to the lack of information about the flow path and source proximity in relation to the outflow adit. Geochemical processes controlling metals and acidity fluxes in a complex anthropogenic mine aquifer in SW Spain during the dry and rainy season were investigated by geochemical and statistical tools. High concentrations of acidity, sulfate, metals and metalloids (e.g. Fe, Cu, Zn, As, Cd, Ni, Co) were observed due to intense sulfide oxidation processes. The high residence time inside the anthropogenic aquifer, around 40days, caused the release of significant quantities of metals linked to host rocks (e.g. Al, Ca, Ge, Li, Mg, REE). The most outstanding characteristic of the acid mine drainage (AMD) outflows is the existence of higher Fe/SO4 molar ratios than those theoretical of pyrite (0.50) during most of the monitored period, due to a fire which occurred in 1949 and remained active for decades. Permanent and temporal retention mechanisms of acidity and metals were observed in the galleries. Once released from sulfide oxidation, Pb and As are sorbed on Fe oxyhydroxysulfate or precipitated as low solubility minerals (i.e. anglesite) inside the galleries. The precipitation of evaporitic sulfate salts during the dry season and the subsequent re-dissolution after rainfall control the fluxes of acidity and main metals (i.e. Fe, Mg, Al) from this anthropogenic aquifer. Some elements, such as Cd, Cu, Ni, REE and Zn, are retained in highly soluble sulfate salts while other elements, such as Ge, Pb and Sc, have a lower response to washout processes due to its incorporation in less soluble sulfate salts. In this way, metal concentration during the washout processes would be controlled by the proportion and solubility of each type of evaporitic sulfate salt stored during the dry season. The recovery of metals of economic interest contained in the AMD could help to self-finance the remediation of these waters in

  6. Metal and acidity fluxes controlled by precipitation/dissolution cycles of sulfate salts in an anthropogenic mine aquifer.

    PubMed

    Cánovas, C R; Macías, F; Pérez-López, R

    2016-05-01

    Underground mine drainages are extremely difficult to study due to the lack of information about the flow path and source proximity in relation to the outflow adit. Geochemical processes controlling metals and acidity fluxes in a complex anthropogenic mine aquifer in SW Spain during the dry and rainy season were investigated by geochemical and statistical tools. High concentrations of acidity, sulfate, metals and metalloids (e.g. Fe, Cu, Zn, As, Cd, Ni, Co) were observed due to intense sulfide oxidation processes. The high residence time inside the anthropogenic aquifer, around 40days, caused the release of significant quantities of metals linked to host rocks (e.g. Al, Ca, Ge, Li, Mg, REE). The most outstanding characteristic of the acid mine drainage (AMD) outflows is the existence of higher Fe/SO4 molar ratios than those theoretical of pyrite (0.50) during most of the monitored period, due to a fire which occurred in 1949 and remained active for decades. Permanent and temporal retention mechanisms of acidity and metals were observed in the galleries. Once released from sulfide oxidation, Pb and As are sorbed on Fe oxyhydroxysulfate or precipitated as low solubility minerals (i.e. anglesite) inside the galleries. The precipitation of evaporitic sulfate salts during the dry season and the subsequent re-dissolution after rainfall control the fluxes of acidity and main metals (i.e. Fe, Mg, Al) from this anthropogenic aquifer. Some elements, such as Cd, Cu, Ni, REE and Zn, are retained in highly soluble sulfate salts while other elements, such as Ge, Pb and Sc, have a lower response to washout processes due to its incorporation in less soluble sulfate salts. In this way, metal concentration during the washout processes would be controlled by the proportion and solubility of each type of evaporitic sulfate salt stored during the dry season. The recovery of metals of economic interest contained in the AMD could help to self-finance the remediation of these waters in

  7. Effect of glyceric acid calcium salt on the viability of ethanol-dosed gastric cells.

    PubMed

    Habe, Hiroshi; Sato, Shun; Fukuoka, Tokuma; Kitamoto, Dai; Sakaki, Keiji

    2011-01-01

    D-Glyceric acid (D-GA) calcium has been reported to accelerate ethanol oxidation in vivo in rats (Eriksson et al., Metabolism, 56, 895-898 (2007)). However, no other reports have shown that D-GA can reduce the harmful effects of ethanol. In this study, the effects of D-, L-, and DL-GA calcium on ethanol-dosed gastric cell viability were investigated using human gastric carcinoma cells (Kato III) and normal rat gastric mucosa cells (RGM1). Addition of 2% and 3 % ethanol to Kato III and RGM1 cells, respectively, decreased their cell viability by approximately 20-50 % after 24 or 72 h of cultivation. In 2 % ethanol-dosed Kato III cells cultivated for 24 h, addition of 0.002-20 µg/mL D- and L-GA calcium did not affect cell viability. Similarly, addition of less than 20 µg/mL DL-GA calcium did not affect cell viability. However, when 20 µg/mL DL-GA calcium was added, cell viability increased by 35.7 % after 72 h of incubation, compared to the viability of control cells without ethanol or GA. Addition of 20 µg/mL DL-GA calcium to 3 % ethanol-dosed RGM1 cells cultivated for 24 or 72 h also increased cell viability up to those observed in control cells. These results suggest that a racemic mixture of GA may have the strongest effect on enhancing the viability of ethanol-exposed cells. PMID:22027025

  8. Decontamination using a desiccant with air powder abrasion followed by biphasic calcium sulfate grafting: a new treatment for peri-implantitis.

    PubMed

    Lombardo, Giorgio; Corrocher, Giovanni; Rovera, Angela; Pighi, Jacopo; Marincola, Mauro; Lehrberg, Jeffrey; Nocini, Pier Francesco

    2015-01-01

    Peri-implantitis is characterized by inflammation and crestal bone loss in the tissues surrounding implants. Contamination by deleterious bacteria in the peri-implant microenvironment is believed to be a major factor in the etiology of peri-implantitis. Prior to any therapeutic regenerative treatment, adequate decontamination of the peri-implant microenvironment must occur. Herein we present a novel approach to the treatment of peri-implantitis that incorporates the use of a topical desiccant (HYBENX), along with air powder abrasives as a means of decontamination, followed by the application of biphasic calcium sulfate combined with inorganic bovine bone material to augment the intrabony defect. We highlight the case of a 62-year-old man presenting peri-implantitis at two neighboring implants in positions 12 and 13, who underwent access flap surgery, followed by our procedure. After an uneventful 2-year healing period, both implants showed an absence of bleeding on probing, near complete regeneration of the missing bone, probing pocket depth reduction, and clinical attachment gain. While we observed a slight mucosal recession, there was no reduction in keratinized tissue. Based on the results described within, we conclude that the use of HYBENX and air powder abrasives, followed by bone defect grafting, represents a viable option in the treatment of peri-implantitis.

  9. Decontamination Using a Desiccant with Air Powder Abrasion Followed by Biphasic Calcium Sulfate Grafting: A New Treatment for Peri-Implantitis

    PubMed Central

    Lombardo, Giorgio; Corrocher, Giovanni; Rovera, Angela; Pighi, Jacopo; Marincola, Mauro; Lehrberg, Jeffrey; Nocini, Pier Francesco

    2015-01-01

    Peri-implantitis is characterized by inflammation and crestal bone loss in the tissues surrounding implants. Contamination by deleterious bacteria in the peri-implant microenvironment is believed to be a major factor in the etiology of peri-implantitis. Prior to any therapeutic regenerative treatment, adequate decontamination of the peri-implant microenvironment must occur. Herein we present a novel approach to the treatment of peri-implantitis that incorporates the use of a topical desiccant (HYBENX), along with air powder abrasives as a means of decontamination, followed by the application of biphasic calcium sulfate combined with inorganic bovine bone material to augment the intrabony defect. We highlight the case of a 62-year-old man presenting peri-implantitis at two neighboring implants in positions 12 and 13, who underwent access flap surgery, followed by our procedure. After an uneventful 2-year healing period, both implants showed an absence of bleeding on probing, near complete regeneration of the missing bone, probing pocket depth reduction, and clinical attachment gain. While we observed a slight mucosal recession, there was no reduction in keratinized tissue. Based on the results described within, we conclude that the use of HYBENX and air powder abrasives, followed by bone defect grafting, represents a viable option in the treatment of peri-implantitis. PMID:26000178

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

    PubMed

    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

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

    PubMed Central

    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

  12. Synthesis and olfactory activity of unnatural, sulfated 5β-bile acid derivatives in the sea lamprey (Petromyzon marinus).

    PubMed

    Burns, Aaron C; Sorensen, Peter W; Hoye, Thomas R

    2011-02-01

    A variety of unnatural bile acid derivatives (9a-9f) was synthesized and used to examine the specificity with which the sea lamprey (Petromyzon marinus) olfactory system detects these compounds. These compounds are analogs of petromyzonol sulfate (PS, 1), a component of the sea lamprey migratory pheromone. Both the stereochemical configuration at C5 (i.e., 5α vs. 5β) and the extent and sites of oxygenation (hydroxylation or ketonization) of the bile acid derived steroid skeleton were evaluated by screening the compounds for olfactory activity using electro-olfactogram recording. 5β-Petromyzonol sulfate (9a) elicited a considerable olfactory response at sub-nanomolar concentration. In addition, less oxygenated systems (i.e., 9b-9e) elicited olfactory responses, albeit with less potency. The sea lamprey sex pheromone mimic 9f (5β-3-ketopetromyzonol sulfate) was also examined and found to produce a much lower olfactory response. Mixture studies conducted with 9a and PS (1) suggest that stimulation is occurring via similar modes of activation, demonstrating a relative lack of specificity for recognition of the allo-configuration (i.e., 5α) in sea lamprey olfaction. This attribute could facilitate design of pheromone analogs to control this invasive species.

  13. Resilience of sulfate-reducing granular sludge against temperature, pH, oxygen, nitrite, and free nitrous acid.

    PubMed

    Hao, Tianwei; Mackey, Hamish R; Guo, Gang; Liu, Rulong; Chen, Guanghao

    2016-10-01

    Sulfate-reducing granular sludge has recently been developed and characterized in detail as part of the development of the sulfate reduction, autotrophic denitrification, nitrification integrated (SANI) process. However, information regarding temperature of granules to environmental fluctuation is lacking, an aspect that is important in dealing with real wastewater. A comprehensive assessment of sulfate-reducing granular sludge performance under various environmental conditions was thus conducted in this study, including temperature, pH, oxygen, nitrite, and free nitrous acid (FNA) as possible encountering conditions in the removal of organics and/or nitrate. Specific chemical oxygen demand removal rate of the granules was determined to be reduced by 65 % when the temperature varied between 10-15 °C, reduced by 70 % when dissolved oxygen (DO) was 0.5 mg/L or greater, and at least, reduced by 75 % when nitrite was 30 mg N/L or above. Nevertheless, the sludge activity recovered by 82, 100, and 86 % from exposure to high oxygen and nitrite and low temperature levels, respectively. Combined inhibition of nitrite and FNA on the sludge is strong and complex, while FNA alone reduced cell viability from 60 to 40 % when its concentration increased to 2.3 mg N/L. The present study demonstrates that sulfate-reducing bacteria (SRB) granules possess high resilience against varying environmental conditions, showing the high application potential of sulfate-reducing granular sludge in dealing with brackish and saline industrial or domestic wastewaters. PMID:27294382

  14. Resilience of sulfate-reducing granular sludge against temperature, pH, oxygen, nitrite, and free nitrous acid.

    PubMed

    Hao, Tianwei; Mackey, Hamish R; Guo, Gang; Liu, Rulong; Chen, Guanghao

    2016-10-01

    Sulfate-reducing granular sludge has recently been developed and characterized in detail as part of the development of the sulfate reduction, autotrophic denitrification, nitrification integrated (SANI) process. However, information regarding temperature of granules to environmental fluctuation is lacking, an aspect that is important in dealing with real wastewater. A comprehensive assessment of sulfate-reducing granular sludge performance under various environmental conditions was thus conducted in this study, including temperature, pH, oxygen, nitrite, and free nitrous acid (FNA) as possible encountering conditions in the removal of organics and/or nitrate. Specific chemical oxygen demand removal rate of the granules was determined to be reduced by 65 % when the temperature varied between 10-15 °C, reduced by 70 % when dissolved oxygen (DO) was 0.5 mg/L or greater, and at least, reduced by 75 % when nitrite was 30 mg N/L or above. Nevertheless, the sludge activity recovered by 82, 100, and 86 % from exposure to high oxygen and nitrite and low temperature levels, respectively. Combined inhibition of nitrite and FNA on the sludge is strong and complex, while FNA alone reduced cell viability from 60 to 40 % when its concentration increased to 2.3 mg N/L. The present study demonstrates that sulfate-reducing bacteria (SRB) granules possess high resilience against varying environmental conditions, showing the high application potential of sulfate-reducing granular sludge in dealing with brackish and saline industrial or domestic wastewaters.

  15. Preparation of volatile fatty acid (VFA) calcium salts by anaerobic digestion of glucose.

    PubMed

    Li, Xiaofen; Swan, Janis E; Nair, Giridhar R; Langdon, Alan G

    2015-01-01

    Many potentially useful intermediates such as hydrogen and volatile fatty acids (VFAs) are formed during the complex anaerobic digestion processes that produce methane from biomass. This study recovers VFAs from an anaerobic digester by a combination of gas stripping and absorption with calcium carbonate slurry. Glucose was used as the model substrate because it is readily available, inexpensive, and easily digested. Sludge from a meatworks anaerobic digester produced methane and carbon dioxide (and sometimes a small amount of hydrogen) when batch-fed with glucose. Conditioning the neutral anaerobic sludge to an acidic pH (below 4.8) was achieved using repeated 1 g L(-1) doses of glucose. After conditioning, mainly VFAs and hydrogen were produced. The intermediate VFAs could be stripped using headspace gas. In subsequent fed-batch digestion/stripping cycles, the pH decreased when glucose was added and then increased when the VFA was gas stripped. The predominant acids formed at low pH values were lactic, butyric, and acetic acids. Lactic acid was converted to VFAs during stripping. The VFA calcium salts recovered were 80% butyrate and 20% acetate with minor quantities of propionate and valerate. PMID:25274086

  16. Preparation of volatile fatty acid (VFA) calcium salts by anaerobic digestion of glucose.

    PubMed

    Li, Xiaofen; Swan, Janis E; Nair, Giridhar R; Langdon, Alan G

    2015-01-01

    Many potentially useful intermediates such as hydrogen and volatile fatty acids (VFAs) are formed during the complex anaerobic digestion processes that produce methane from biomass. This study recovers VFAs from an anaerobic digester by a combination of gas stripping and absorption with calcium carbonate slurry. Glucose was used as the model substrate because it is readily available, inexpensive, and easily digested. Sludge from a meatworks anaerobic digester produced methane and carbon dioxide (and sometimes a small amount of hydrogen) when batch-fed with glucose. Conditioning the neutral anaerobic sludge to an acidic pH (below 4.8) was achieved using repeated 1 g L(-1) doses of glucose. After conditioning, mainly VFAs and hydrogen were produced. The intermediate VFAs could be stripped using headspace gas. In subsequent fed-batch digestion/stripping cycles, the pH decreased when glucose was added and then increased when the VFA was gas stripped. The predominant acids formed at low pH values were lactic, butyric, and acetic acids. Lactic acid was converted to VFAs during stripping. The VFA calcium salts recovered were 80% butyrate and 20% acetate with minor quantities of propionate and valerate.

  17. 40 CFR 721.2076 - D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  18. Acids in combination with sodium dodecyl sulfate caused quality deterioration of fresh-cut iceburg lettuce during storage in modified atmosphere package

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent studies showed that levulinic acid (LA) and sodium acid sulfate (SAS) were effective in inactivating human pathogens on fresh produce. The present study investigated the effects of LA and SAS in comparison with citric acid and chlorine on the inactivation of E. coli O157:H7 and the sensory qu...

  19. Self-assembled nanoparticles based on chondroitin sulfate-deoxycholic acid conjugates for docetaxel delivery: Effect of degree of substitution of deoxycholic acid.

    PubMed

    Liu, Mengrui; Du, Hongliang; Zhai, Guangxi

    2016-10-01

    Hydrophobically-modified polymers based on chondroitin sulfate with different degree of substitution (DS) of deoxycholic acid (DOCA) were developed for docetaxel delivery. Chondroitin sulfate-deoxycholic acid (CSAD) bioconjugates were synthesized via the linker of adipic dihydrazide by amide bond. They were characterized with spherical shape, mean diameter of around 165.2nm and negative zeta potential (-14.87 to -20.53mV). An increase of DOCA DS reduced size of nanoparticles, while increasing drug loading efficiency. Drug release in vitro showed a triphasic sustained pattern and higher accumulative drug release percentage was observed with increased DS of DOCA on polymer. Self-assemblies with higher DS also had enhanced internalization of nanoparticles and stronger cytotoxicity at the cellular level. The self-assemble nanoparticles demonstrate to be excellent targeting drug delivery systems and the desired therapeutics can be achieved via the alteration of DS. PMID:27343846

  20. Competitive oxidation of volatile fatty acids by sulfate- and nitrate-reducing bacteria from an oil field in Argentina.

    PubMed

    Grigoryan, Aleksandr A; Cornish, Sabrina L; Buziak, Brenton; Lin, Shiping; Cavallaro, Adriana; Arensdorf, Joseph J; Voordouw, Gerrit

    2008-07-01

    Acetate, propionate, and butyrate, collectively referred to as volatile fatty acids (VFA), are considered among the most important electron donors for sulfate-reducing bacteria (SRB) and heterotrophic nitrate-reducing bacteria (hNRB) in oil fields. Samples obtained from a field in the Neuquén Basin, western Argentina, had significant activity of mesophilic SRB, hNRB, and nitrate-reducing, sulfide-oxidizing bacteria (NR-SOB). In microcosms, containing VFA (3 mM each) and excess sulfate, SRB first used propionate and butyrate for the production of acetate, which reached concentrations of up to 12 mM prior to being used as an electron donor for sulfate reduction. In contrast, hNRB used all three organic acids with similar kinetics, while reducing nitrate to nitrite and nitrogen. Transient inhibition of VFA-utilizing SRB was observed with 0.5 mM nitrite and permanent inhibition with concentrations of 1 mM or more. The addition of nitrate to medium flowing into an upflow, packed-bed bioreactor with an established VFA-oxidizing SRB consortium led to a spike of nitrite up to 3 mM. The nitrite-mediated inhibition of SRB led, in turn, to the transient accumulation of up to 13 mM of acetate. The complete utilization of nitrate and the incomplete utilization of VFA, especially propionate, and sulfate indicated that SRB remained partially inhibited. Hence, in addition to lower sulfide concentrations, an increase in the concentration of acetate in the presence of sulfate in waters produced from an oil field subjected to nitrate injection may indicate whether the treatment is successful. The microbial community composition in the bioreactor, as determined by culturing and culture-independent techniques, indicated shifts with an increasing fraction of nitrate. With VFA and sulfate, the SRB genera Desulfobotulus, Desulfotignum, and Desulfobacter as well as the sulfur-reducing Desulfuromonas and the NR-SOB Arcobacter were detected. With VFA and nitrate, Pseudomonas spp. were

  1. Fourier Transform Infrared Spectroscopy Demonstrates The Reactivity Of The Protonated Carboxyl Group Of The Acid Salt Of Calcium Bilirubinate.

    NASA Astrophysics Data System (ADS)

    Soloway, R. D.; Wu, J.-G.; Xu, D.-F.; Zhang, Y.-F.; Martini, D. K.; Hong, N.-K.; Crowther, R. S.

    1989-12-01

    Calcium bilirubinate is a major salt in pigment gallstones. Bilirubin IX (H2BR) is a tetrapyrrole with 1 propionic acid side chain on both the B and C rings. A striking feature is the strong intramolecular hydrogen bonding of both carboxyl groups as determined by x-ray diffraction. This greatly reduces aqueous solubility. Much less is known about the structure of the salts of calcium bilirubinate since single crystals have not been formed. One or both carboxyl groups of bilirubin may coordinate with calcium in stone, forming the acid or neutral salt.

  2. Visible-near-infrared reflectance spectroscopy of volcanic acid-sulfate alteration in Nicaragua: Analogs for early Mars

    NASA Astrophysics Data System (ADS)

    Marcucci, Emma C.; Hynek, Brian M.; Kierein-Young, Kathryn S.; Rogers, K. L.

    2013-10-01

    Acid-sulfate weathering at Nicaraguan hydrothermal sites Cerro Negro, Momotombo, and Telica volcanoes and Hervidores de San Jacinto mudpots was characterized as an analog for similar processes that likely operated on early Mars. In situ mineralogical analyses were conducted with a field portable visible near-infrared spectrometer for comparison to similar Martian data sets. Three classes of alteration minerals were identified: sulfates (gypsum and natroalunite), oxides/hydroxides (hematite and goethite), and phyllosilicates (kaolinite/halloysite, montmorillonite, and saponite), as well as elemental sulfur and hydrated silica phases. Our sites had similar suites of minerals, but frequencies varied with location. The results of this field campaign allow inferences regarding the paleo-environmental conditions that were likely present at similar relic hydrothermal sites identified on Mars. In particular, sulfates and phyllosilicates could have coevolved under hydrothermal conditions at Noctis Labyrinthus as is seen in Nicaragua. Fe/Mg smectites were detected in areas with pH of 3-4. Alunite spectra at Terra Sirenum demonstrated mineral mixing effects on spectroscopy. Mineral mixing can cause uncertainties in spectral identification due to a dominant spectrum, such as iron minerals, masking another or the suppression of weaker bands. When viewed from orbit, our field sites would likely be dominated by hydrated silica and Mars sites, such as one in Syrtis Major, could have a more diverse mineralogy than the data reveal. Concentrated amorphous silica, such as at Gusev crater, can result from acidic fumarolic activity, while Mg sulfates may indicate a lack of reworking by water. This field spectroscopy study helps confirm and provide insight into hydrothermal processes on ancient Mars.

  3. Acidic gases and nitrate and sulfate particles in the atmosphere in the city of Guadalajara, México.

    PubMed

    Saldarriaga-Noreña, Hugo; Waliszewski, Stefan; Murillo-Tovar, Mario; Hernández-Mena, Leonel; de la Garza-Rodríguez, Iliana; Colunga-Urbina, Edith; Cuevas-Ordaz, Rosalva

    2012-05-01

    Atmospheric concentrations of nitrous acid, nitric acid, nitrate and sulfate particles were obtained in this study from April to June 2008 in the center of the city of Guadalajara, while concentrations of ozone, sulfur dioxide, nitrogen dioxide and meteorological parameters (temperature and relative humidity), were acquired by the Secretaría del Medio Ambiente para el Desarrollo Sustentable del Estado de Jalisco (SEMADES). The results showed that nitric acid (2.7 μg m(-3)) was 2.7 times higher than nitrous acid (1.0 μg m(-3)). The sulfur dioxide (SO(2)) concentration indicated an opposite trend to sulfate (SO(4) (2-)), with the average concentration of SO(2) (6.9 μg m(-3)) higher in almost the entire period of study. The sulfur conversion ratio (Fs, 24.9%) and nitrogen conversion ratio (Fn, 6.2%), were revealed to be similar to that reported in other urban areas during warm seasons. It is also noted that ozone is not the main oxidizer of nitrogen dioxide and sulfur dioxide. This determination was made by taking into account the slightly positively correlation determined for Fn (r(2) = 0.084) and Fs (r(2) = 0.092) with ozone that perhaps suggests there are other oxidizing species such as the radical OH, which are playing an important role in the processes of atmospheric oxidation in this area. PMID:22358115

  4. Acidic gases and nitrate and sulfate particles in the atmosphere in the city of Guadalajara, México.

    PubMed

    Saldarriaga-Noreña, Hugo; Waliszewski, Stefan; Murillo-Tovar, Mario; Hernández-Mena, Leonel; de la Garza-Rodríguez, Iliana; Colunga-Urbina, Edith; Cuevas-Ordaz, Rosalva

    2012-05-01

    Atmospheric concentrations of nitrous acid, nitric acid, nitrate and sulfate particles were obtained in this study from April to June 2008 in the center of the city of Guadalajara, while concentrations of ozone, sulfur dioxide, nitrogen dioxide and meteorological parameters (temperature and relative humidity), were acquired by the Secretaría del Medio Ambiente para el Desarrollo Sustentable del Estado de Jalisco (SEMADES). The results showed that nitric acid (2.7 μg m(-3)) was 2.7 times higher than nitrous acid (1.0 μg m(-3)). The sulfur dioxide (SO(2)) concentration indicated an opposite trend to sulfate (SO(4) (2-)), with the average concentration of SO(2) (6.9 μg m(-3)) higher in almost the entire period of study. The sulfur conversion ratio (Fs, 24.9%) and nitrogen conversion ratio (Fn, 6.2%), were revealed to be similar to that reported in other urban areas during warm seasons. It is also noted that ozone is not the main oxidizer of nitrogen dioxide and sulfur dioxide. This determination was made by taking into account the slightly positively correlation determined for Fn (r(2) = 0.084) and Fs (r(2) = 0.092) with ozone that perhaps suggests there are other oxidizing species such as the radical OH, which are playing an important role in the processes of atmospheric oxidation in this area.

  5. Inhibition of Na+-Taurocholate Co-transporting Polypeptide-mediated Bile Acid Transport by Cholestatic Sulfated Progesterone Metabolites*

    PubMed Central

    Abu-Hayyeh, Shadi; Martinez-Becerra, Pablo; Sheikh Abdul Kadir, Siti H.; Selden, Clare; Romero, Marta R.; Rees, Myrddin; Marschall, Hanns-Ulrich; Marin, Jose J. G.; Williamson, Catherine

    2010-01-01

    Sulfated progesterone metabolite (P4-S) levels are raised in normal pregnancy and elevated further in intrahepatic cholestasis of pregnancy (ICP), a bile acid-liver disorder of pregnancy. ICP can be complicated by preterm labor and intrauterine death. The impact of P4-S on bile acid uptake was studied using two experimental models of hepatic uptake of bile acids, namely cultured primary human hepatocytes (PHH) and Na+-taurocholate co-transporting polypeptide (NTCP)-expressing Xenopus laevis oocytes. Two P4-S compounds, allopregnanolone-sulfate (PM4-S) and epiallopregnanolone-sulfate (PM5-S), reduced [3H]taurocholate (TC) uptake in a dose-dependent manner in PHH, with both Na+-dependent and -independent bile acid uptake systems significantly inhibited. PM5-S-mediated inhibition of TC uptake could be reversed by increasing the TC concentration against a fixed PM5-S dose indicating competitive inhibition. Experiments using NTCP-expressing Xenopus oocytes confirmed that PM4-S/PM5-S are capable of competitively inhibiting NTCP-mediated uptake of [3H]TC. Total serum PM4-S + PM5-S levels were measured in non-pregnant and third trimester pregnant women using liquid chromatography-electrospray tandem mass spectrometry and were increased in pregnant women, at levels capable of inhibiting TC uptake. In conclusion, pregnancy levels of P4-S can inhibit Na+-dependent and -independent influx of taurocholate in PHH and cause competitive inhibition of NTCP-mediated uptake of taurocholate in Xenopus oocytes. PMID:20177056

  6. Differentiating chondroitin sulfate glycosaminoglycans using collision-induced dissociation; uronic acid cross-ring diagnostic fragments in a single stage of tandem mass spectrometry.

    PubMed

    Kailemia, Muchena J; Patel, Anish B; Johnson, Dane T; Li, Lingyun; Linhardt, Robert J; Amster, I Jonathan

    2015-01-01

    The stereochemistry of the hexuronic acid residues of the structure of glycosaminoglycans (GAGs) is a key feature that affects their interactions with proteins and other biological functions. Electron based tandem mass spectrometry methods, in particular electron detachment dissociation (EDD), have been able to distinguish glucuronic acid (GlcA) from iduronic acid (IdoA) residues in some heparan sulfate tetrasaccharides by producing epimer-specific fragments. Similarly, the relative abundance of glycosidic fragment ions produced by collision-induced dissociation (CID) or EDD has been shown to correlate with the type of hexuronic acid present in chondroitin sulfate GAGs. The present work examines the effect of charge state and degree of sodium cationization on the CID fragmentation products that can be used to distinguish GlcA and IdoA containing chondroitin sulfate A and dermatan sulfate chains. The cross-ring fragments (2,4)A(n) and (0,2)X(n) formed within the hexuronic acid residues are highly preferential for chains containing GlcA, distinguishing it from IdoA. The diagnostic capability of the fragments requires the selection of a molecular ion and fragment ions with specific ionization characteristics, namely charge state and number of ionizable protons. The ions with the appropriate characteristics display diagnostic properties for all the chondroitin sulfate and dermatan sulfate chains (degree of polymerization of 4-10) studied.

  7. Sulfation of Lithocholate as a Possible Modifier of Chenodeoxycholic Acid-induced Elevations of Serum Transaminase in Patients with Gallstones

    PubMed Central

    Marks, J. W.; Sue, S. O.; Pearlman, B. J.; Bonorris, G. G.; Varady, P.; Lachin, J. M.; Schoenfield, L. J.

    1981-01-01

    Chenodeoxycholic acid (CDC), through its metabolite, lithocholic acid (LC), is hepatotoxic in certain species. The cause of elevations of serum transaminase in 25% of humans ingesting CDC, however, is unknown, but also may be due to LC. Because efficient hepatic sulfation of LC may protect against hepatic injury, the aim of this study was to determine if sulfation of LC might modify CDC-induced elevations of transaminase. Pretreatment sulfation fraction (SF) was estimated in 63 randomly selected patients with gallstones in a double-blind randomized trial of CDC, 750 mg/d, 375 mg/d, or placebo; in 27 of these, SF was repeated at 1 or 2 yr. In four other patients, the SF was measured at 2 yr only. Serum glutamic oxaloacetic transaminase and serum glutamic pyruvic transaminase were determined monthly for 3 mo and then every 3 or 4 mo; an elevation of transaminase was defined as > 150% of the normal upper limit in asymptomatic patients. 10 μCi of 3H-glyco-LC (sp act 84 mCi/mol) was ingested 10-12 h before fasting duodenal biliary drainage. Bile acids in bile were separated by thin-layer chromatography. The SF was estimated as a percentage of total radioactivity (scintillation counting) in sulfated glyco-LC. The standard deviation for replicate SF determinations (n = 311) was 2.1% The pretreatment SF (mean 60.7±1.7 SEM) correlated inversely with age (r = 0.336, P < 0.005) and directly with the obesity index (r = 0.495, P > 0.001), but was independent of sex. The SF, remeasured at 1 or 2 yr, did not change significantly with time or CDC. Among CDC-treated patients, elevations of transaminase occurred in 75% of patients with a SF < 45% vs. 11% with a SF > 45% (P < 0.001). In conclusion, a SF < 45% occurred in patients with gallstones who had a high probability of developing elevated serum transaminase when treated with CDC. Thus, sulfation of lithocholate may modify CDC-induced elevations of serum transaminase. Images PMID:7298846

  8. Habit modification of calcium carbonate in the presence of malic acid

    SciTech Connect

    Mao Zhaofeng; Huang Jianhua

    2007-02-15

    The ability of malic acid to control calcium carbonate morphology has been investigated by aging calcium chloride solution in the presence of urea in a 90 deg. C bath. Malic acid favors the formation of calcite. A transition from single block to aggregate with special morphology occurs upon increasing malic acid concentration. The morphological development of CaCO{sub 3} crystal obviously depends on the starting pH. CaCO{sub 3} crystal grows from spindle seed to dumbbell in the pH regime from 7 to 11; while it evolves from spindle seed, through peanut, to sphere at pH=11.5. Both dumbbell and sphere consist of rods that are elongated along c-axis and capped with three smooth, well-defined rhombic {l_brace}1 0 4{r_brace} faces. A tentative growth mechanism is proposed based on the fractal model suggested by R. Kniep and S. Busch [Angew. Chem. Int. Ed. Engl. 35 (1996) 2624]. - Graphical abstract: Dumbbell-like CaCO{sub 3} particles obtained in the presence of malic acid.

  9. Practical applications of sulfate-reducing bacteria to control acid mine drainage at the Lilly/Orphan Boy Mine near Elliston, Montana

    SciTech Connect

    Canty, M.

    1994-12-31

    The overall purpose of this document is to provide a detailed technical description of a technology, biological sulfate reduction, which is being demonstrated under the Mine Waste Technology Pilot Program, and provide the technology evaluation process undertaken to select this technology for demonstration. In addition, this document will link the use of the selected technology to an application at a specific site. The purpose of this project is to develop technical information on the ability of biological sulfate reduction to slow the process of acid generation and, thus, improve water quality at a remote mine site. Several technologies are screened for their potential to treat acid mine water and to function as a source control for a specific acid-generating situation: a mine shaft and associated underground workings flooded with acid mine water and discharging a small flow from a mine opening. The preferred technology is the use of biological sulfate reduction. Sulfate-reducing bacteria are capable of reducing sulfate to sulfide, as well as increasing the pH and alkalinity of water affected by acid generation. Soluble sulfide reacts with the soluble metals in solution to form insoluble metal sulfides. The environment needed for efficient sulfate-reducing bacteria growth decreases acid production by reducing the dissolved oxygen in water and increasing pH. A detailed technical description of the sulfate-reducing bacteria technology, based on an extensive review of the technical literature, is presented. The field demonstration of this technology to be performed at the Lilly/Orphan Boy Mine is also described. Finally, additional in situ applications of biological sulfate reduction are presented.

  10. Strong and Biostable Hyaluronic Acid-Calcium Phosphate Nanocomposite Hydrogel via in Situ Precipitation Process.

    PubMed

    Jeong, Seol-Ha; Koh, Young-Hag; Kim, Suk-Wha; Park, Ji-Ung; Kim, Hyoun-Ee; Song, Juha

    2016-03-14

    Hyaluronic acid (HAc) hydrogel exhibits excellent biocompatibility, but it has limited biomedical application due to its poor biomechanical properties as well as too-fast enzymatic degradation. In this study, we have developed an in situ precipitation process for the fabrication of a HAc-calcium phosphate nanocomposite hydrogel, after the formation of the glycidyl methacrylate-conjugated HAc (GMHA) hydrogels via photo-cross-linking, to improve the mechanical and biological properties under physiological conditions. In particular, our process facilitates the rapid incorporation of calcium phosphate (CaP) nanoparticles of uniform size and with minimal agglomeration into a polymer matrix, homogeneously. Compared with pure HAc, the nanocomposite hydrogels exhibit improved mechanical behavior. Specifically, the shear modulus is improved by a factor of 4. The biostability of the nanocomposite hydrogel was also significantly improved compared with that of pure HAc hydrogels under both in vitro and in vivo conditions. PMID:26878437

  11. Calcium and ascorbic acid affect cellular structure and water mobility in apple tissue during osmotic dehydration in sucrose solutions.

    PubMed

    Mauro, Maria A; Dellarosa, Nicolò; Tylewicz, Urszula; Tappi, Silvia; Laghi, Luca; Rocculi, Pietro; Rosa, Marco Dalla

    2016-03-15

    The effects of the addition of calcium lactate and ascorbic acid to sucrose osmotic solutions on cell viability and microstructure of apple tissue were studied. In addition, water distribution and mobility modification of the different cellular compartments were observed. Fluorescence microscopy, light microscopy and time domain nuclear magnetic resonance (TD-NMR) were respectively used to evaluate cell viability and microstructural changes during osmotic dehydration. Tissues treated in a sucrose-calcium lactate-ascorbic acid solution did not show viability. Calcium lactate had some effects on cell walls and membranes. Sucrose solution visibly preserved the protoplast viability and slightly influenced the water distribution within the apple tissue, as highlighted by TD-NMR, which showed higher proton intensity in the vacuoles and lower intensity in cytoplasm-free spaces compared to other treatments. The presence of ascorbic acid enhanced calcium impregnation, which was associated with permeability changes of the cellular wall and membranes. PMID:26575708

  12. Aromatic L-amino acids activate the calcium-sensing receptor.

    PubMed

    Conigrave, Arthur D; Mun, Hee-Chang; Lok, Hiu-Chuen

    2007-06-01

    The calcium-sensing receptor (CaR) is recognized as a member of class 3 of the G-protein coupled receptor superfamily. Members of this subgroup, which have large N-terminal extracellular domains, include receptors that respond specifically to the amino acid glutamate; receptors that respond to the glutamate analogue, gamma-amino butyric acid; and several receptors that act as broad-spectrum amino acid sensors. The CaR is one of these broad-spectrum amino acid sensors that, along with several other members of the subgroup, also responds to extracellular Ca2+. In this mini-review, we consider evidence that the CaR is a sensor of aromatic amino acids, that it has broad-spectrum amino acid sensing properties, that it provides an amino acid binding site in its extracellular N-terminal Venus Fly Trap domain, and that amino acids have a physiological impact on systems in which the CaR is expressed.

  13. Effectiveness of the bran media and bacteria inoculum treatments in increasing pH and reducing sulfur-total of acid sulfate soils

    NASA Astrophysics Data System (ADS)

    Taufieq, Nur Anny Suryaningsih; Rahim, Sahibin Abdul; Jamil, Habibah

    2013-11-01

    This study was carried out to determine the effectiveness ofsulfate reducing bacteria (SRB) in using bran as a source of food and energy, and to see the effectiveness of the bran media and bacteria inoculums treatments for pH and sulfur-total of acid sulfate reduction insoils. This study used two factors in group random designs with four treatments for bacteria inoculum of B1 (1%), B2 (5%), B3 (10%), B4 (15%) and two treatments for organic media (bran) of D1 (1:1) and D2 (1:19). Based on three replications, the combination resulted in a total of 24 treatments. Soil pH was measured using the Duddridge and Wainright method and determination of sulfate content in soil was conducted by the spectrophotometry method. The data obtained was analyzed for significance by Analysis of Variance and the Least Significant Difference Test. The pH of the initial acid sulfate soils ranged from 3 to 4 and the soil sulfur-total ranged from 1.4% to 10%. After mixing sulfate reducing bacteria with the bran mediaand incubated for four days, the pH of the acid sulfate soils increased from 3.67 to 4.20, while the soil sulfur-total contents had been reduced by 2.85% to 0.35%. This experiment has proven that an acid sulfate soil with low pH is a good growth medium for the sulfate reducing bacteria. The bestincubation period to achieve an effective bioremediation resultthrough sulfate percentage reduction by sulfate reducing bacteria was 10 days, while the optimum bran media dose was 1:19, and the bacteria inoculums dose was 10%.

  14. Mapping Acid Sulfate Alteration of Basaltic Andesite with Thermal Infrared Data

    NASA Technical Reports Server (NTRS)

    Vaughan, R. G.; Calvin, W. M.; Hook, S. J.; Taranik, J. V.

    2002-01-01

    Airborne thermal infrared multi- and hyperspectral data sets are used to map sulfate alteration of basaltic andesites near Reno, NV. Alteration includes quartz-alunite, jarosite and a number of clay minerals such as kaolinite and montmorillonite. Additional information is contained in the original extended abstract.

  15. Long term response of acid-sensitive Vermont Lakes to sulfate deposition

    EPA Science Inventory

    Atmospheric deposition of sulfur can negatively affect the health of lakes and streams, particularly in poorly buffered catchments. In response to the Clean Air Act Amendments, wet deposition of sulfate decreased more than 35% in Vermont between 1990 and 2008. However, most of ...

  16. MICROBIAL SULFATE REDUCTION AND METAL ATTENUATION IN PH 4 ACID MINE WATER

    EPA Science Inventory

    Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing...

  17. Molecular Basis of the Receptor Interactions of Polysialic Acid (polySia), polySia Mimetics, and Sulfated Polysaccharides.

    PubMed

    Zhang, Ruiyan; Loers, Gabriele; Schachner, Melitta; Boelens, Rolf; Wienk, Hans; Siebert, Simone; Eckert, Thomas; Kraan, Stefan; Rojas-Macias, Miguel A; Lütteke, Thomas; Galuska, Sebastian P; Scheidig, Axel; Petridis, Athanasios K; Liang, Songping; Billeter, Martin; Schauer, Roland; Steinmeyer, Jürgen; Schröder, Jens-Michael; Siebert, Hans-Christian

    2016-05-01

    Polysialic acid (polySia) and polySia glycomimetic molecules support nerve cell regeneration, differentiation, and neuronal plasticity. With a combination of biophysical and biochemical methods, as well as data mining and molecular modeling techniques, it is possible to correlate specific ligand-receptor interactions with biochemical processes and in vivo studies that focus on the potential therapeutic impact of polySia, polySia glycomimetics, and sulfated polysaccharides in neuronal diseases. With this strategy, the receptor interactions of polySia and polySia mimetics can be understood on a submolecular level. As the HNK-1 glycan also enhances neuronal functions, we tested whether similar sulfated oligo- and polysaccharides from seaweed could be suitable, in addition to polySia, for finding potential new routes into patient care focusing on an improved cure for various neuronal diseases. The knowledge obtained here on the structural interplay between polySia or sulfated polysaccharides and their receptors can be exploited to develop new drugs and application routes for the treatment of neurological diseases and dysfunctions. PMID:27136597

  18. Sulfate radical-induced degradation of Acid Orange 7 by a new magnetic composite catalyzed peroxymonosulfate oxidation process.

    PubMed

    Chen, Dan; Ma, Xiaolong; Zhou, Jizhi; Chen, Xi; Qian, Guangren

    2014-08-30

    We synthesized a novel magnetic composite, Fe3O4/Cu(Ni)Cr-LDH, as a heterogeneous catalyst for the degradation of organic dyes in the solution using sulfate radical-based advanced oxidation processes. The physicochemical properties of the composite synthesized via two-step microwave hydrothermal method were characterized by several techniques, such as X-ray diffraction (XRD), inductively coupled plasma (ICP), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The degradation tests were performed at 25°C with Acid Orange 7 (AO7) initial concentration of 25mg/L and AO7/peroxymonosulfate (PMS) molar ratio of 1:10, which showed that the complete degradation by Fe3O4/Cu1.5Ni0.5Cr-LDH could be achieved and the mineralization rate could reach 46%. PMS was activated by Cu (II) and Fe (II/III) of Fe3O4/Cu(Ni)Cr-LDH to generate sulfate radicals (SO4(-)). Subsequently, the organic functional groups of AO7 molecules were destroyed by sulfate radicals (SO4(-)), inducing the degradation of AO7. Moreover, the catalytic behavior of the catalysts could be reused five times. Therefore, our work suggested that the Fe3O4/Cu(Ni)Cr-LDH composite could be applied widely for the treatment of organic dyes in wastewater. PMID:25103453

  19. Synthesis of potassium hexatitanate whiskers starting from metatitanic acid and potassium carbonate and sulfate by calcination method

    SciTech Connect

    Liu Chunyan; Yin Hengbo Liu Yumin; Ren Min; Wang Aili; Ge Chen; Yao Hengping; Feng Hui; Chen Jun; Jiang Tingshun

    2009-05-06

    Potassium hexatitanate whiskers were synthesized starting from metatitanic acid (H{sub 2}TiO{sub 3}), potassium carbonate and sulfate by calcination method. The effects of mole ratios of K{sub 2}CO{sub 3} to metatitanic acid (H{sub 2}TiO{sub 3}), content of potassium sulfate, and calcination temperature on the crystallinity and morphology of the resultant potassium titanate whiskers were investigated by X-ray diffraction and scanning electron microscopy. Well crystallized potassium hexatitanate whiskers with an average length of 7.3 {mu}m and an average diameter of 0.62 {mu}m were synthesized when the molar ratio of K{sub 2}CO{sub 3} to metatitanic acid was kept at 1:3.5 and the calcination temperature was up to 1150 deg. C. The presence of K{sub 2}SO{sub 4} favored the formation of thin potassium hexatitanate whiskers as compared to the absence of K{sub 2}SO{sub 4}. The whiteness and brightness of the synthesized potassium hexatitanate whiskers were comparable to that of rutile TiO{sub 2} pigment.

  20. Flagellasialin: a novel sulfated alpha2,9-linked polysialic acid glycoprotein of sea urchin sperm flagella.

    PubMed

    Miyata, Shinji; Sato, Chihiro; Kumita, Hironobu; Toriyama, Masaru; Vacquier, Victor D; Kitajima, Ken

    2006-12-01

    A novel alpha2,9-linked polysialic acid (polySia)-containing glycoprotein of sea urchin sperm flagella was identified and named "flagellasialin." Flagellasialin from Hemicentrotus pulcherrimus shows a diverse relative molecular mass on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of 40-80 kDa. Flagellasialin is a 96-amino acid, threonine-rich, heavily O-glycosylated (80-90% by weight) glycoprotein with a single transmembrane segment at its C-terminus and no apparent cytosolic domain. Of 12 extracellular Thr residues, eight are O-glycosylated and three are nonglycosylated. Flagellasialin is highly expressed in the testis but cannot be detected in the ovary. The amino acid sequences of flagellasialin from three sea urchin species (H. pulcherrimus, Strongylocentrotus purpuratus, and Strongylocentrotus franciscanus) are identical, but some species differences exist in the three core glycan structures to which the sulfated alpha2,9-linked polyNeu5Ac chain is linked. Finally, the treatment of sperm with a specific antibody against the alpha2,9-linked polyNeu5Ac structure results in the elevation of intracellular Ca(2+) and inhibition of sperm motility and fertilization, implicating flagellasialin as a regulator of these critical processes.

  1. Germination and Seedling Growth of Perennial Ryegrass in Acid Sulfate Soil Treated by Pyrite Nano-Encapsulation

    NASA Astrophysics Data System (ADS)

    Lee, J.; Kim, J.; Yi, J.; Kim, T.

    2007-05-01

    The trial pot experiment was conducted to validate the effect of encapsulation in reduction of acid rock drainage. Six different treatments were performed: A = control, four times spraying of distilled water; B = four times of 0.01 M H2O2; C = once-encapsulated and three times spraying of distilled water; D = twice-encapsulated and twice spraying of distilled water; E = three times-encapsulated and once spraying of distilled water and F = four times-encapsulated for the acid sulfate soil with pyrite bearing andesite powder and sand. After the encapsulation treatment, the perennial ryegrass (Loium perenne) was sowed to evaluate germination rate and growth for three months. The leachate was examined for the chemical properties. The leachate from the A pot (control) is characterized as acidic (pH below 3) and high concentrations of SO4-2: 12,022 mg/L, Al: 85.8 mg/L and Mn: 34.1 mg/L which can be toxic effect to the plant growth. However, the leachate from encapsulated pots showed near neutral (pH 6 to 7) and low concentrations of SO4-2 (below 3,000 mg/L), Al (below 45mg/L) and Mn (24 gm/L). The frequency of encapsulation treatment is related to reduction of acidic drainage. It was hard to identify the significant difference of the seed germination rate of ryegrass between the treatments, although root and shoot growth showed three times difference between the control (1.90g/pot) and four times encapsulated treatment (6.33g/pot) after 2 month growth. It is suggested that encapsulation of pyrite in acid sulfate soil causes the reduction of acidic drainage resulting in the higher growth of herbaceous plants.

  2. Quantifying heavy metals sequestration by sulfate-reducing bacteria in an Acid mine drainage-contaminated natural wetland.

    PubMed

    Moreau, John W; Fournelle, John H; Banfield, Jillian F

    2013-01-01

    Bioremediation strategies that depend on bacterial sulfate reduction for heavy metals remediation harness the reactivity of these metals with biogenic aqueous sulfide. Quantitative knowledge of the degree to which specific toxic metals are partitioned into various sulfide, oxide, or other phases is important for predicting the long-term mobility of these metals under environmental conditions. Here we report the quantitative partitioning into sedimentary biogenic sulfides of a suite of metals and metalloids associated with acid mine drainage contamination of a natural estuarine wetland for over a century.

  3. Quantifying Heavy Metals Sequestration by Sulfate-Reducing Bacteria in an Acid Mine Drainage-Contaminated Natural Wetland

    PubMed Central

    Moreau, John W.; Fournelle, John H.; Banfield, Jillian F.

    2013-01-01

    Bioremediation strategies that depend on bacterial sulfate reduction for heavy metals remediation harness the reactivity of these metals with biogenic aqueous sulfide. Quantitative knowledge of the degree to which specific toxic metals are partitioned into various sulfide, oxide, or other phases is important for predicting the long-term mobility of these metals under environmental conditions. Here we report the quantitative partitioning into sedimentary biogenic sulfides of a suite of metals and metalloids associated with acid mine drainage contamination of a natural estuarine wetland for over a century. PMID:23487496

  4. Mass independent fractionation of sulfur isotopes during thermochemical reduction of native sulfur, sulfite and sulfate by amino acids

    NASA Astrophysics Data System (ADS)

    Watanabe, Y.; Naraoka, H.; Ohmoto, H.

    2006-05-01

    Mass independent fractionation of sulfur isotopes (MIF-S) is recognized when the Δ33S value (= δ33S-0.515xδ34S) of a sample falls outside the range of 0±0.2 permil and the 33-34θ value (= ln33α/ ln34α) lies outside the range of 0.515±.005 (Farquhar and Wing, 2003). Previous investigators have concluded that the only mechanisms to create MIF-S are photochemical reactions between sulfur-bearing gases (SO2, H2S) and UV. Based on comparisons of the geochemical characteristics of Archean sedimentary rocks between those with large MIF-S values (e.g., the 2.5 Ga McRae and 2.7 Ga Jeerinah shales) and those with no (or very small) MIF- S values (e.g., 2.76 Ga Hardey shales and 2.92 Ga Mosquito Creek shales), we have developed a hypothesis that MIF-S in sedimentary rocks may have been created by reactions among organic-rich sediments, sulfur- bearing solid compounds, and sulfur-bearing hydrothermal fluids at T = 100-200°C during the early diagenetic stage of sediments. Most abundant organic compounds in immature sediments are amino acids. For these reasons, we have conducted series of laboratory experiments to investigate sulfur isotope fractionations during reactions between a variety of amino acids (alanine, glycine, hystidine, etc.) and native sulfur, sodium sulfite or sodium sulfate at 150-200°C. Previous researchers used a variety of organic compounds (sugars, methane, xylene, etc) and/or ferrous- bearing minerals to investigate non-bacterial sulfate reduction, but they failed to demonstrate thermochemical sulfate reduction at temperatures below 230°C. However, we were able to reduce sulfate (S6+), as well as sulfite (S4+) and native sulfur (S0), to hydrogen sulfide (S2-) even at 150°C using simple and common amino acids (e.g., alanine and glycine). The reduction rates generally decreased: (a) from native sulfur, to sulfite, and to sulfate; (b) from simple amino acids to more complex amino acids (e.g., histidine); and (c) with decreasing temperatures. The

  5. In vitro mutagenesis study of two critical glutamic acids in the calcium binding loop of the factor IX heavy chain.

    PubMed

    Hamaguchi, N; Stafford, D

    1994-12-01

    We investigated the structural and functional significance of calcium binding in the factor IXa heavy chain by introducing point mutations into the probable calcium binding site (residues 235 and 245). According to factor IXa computer modelling based on trypsin x-ray structure, side chains of two glutamic acid residues, 235 and 245, together with backbone carbonyl groups of residues 237 and 240, bind a calcium ion. Factor IX clotting activity decreased approximately 25 percent on substitution of glutamic acid 235 with lysine. Activity decreased more than 90 percent on substitution of glutamic acid 245 with lysine. Activity also decreased more than 90 percent on substitution of both glutamic acids by lysines. Factor XIa cleavage of factor IXGlu235Lys and factor IXGlu245Lys appeared normal by polyacrylamide gel analysis. (Factor IXGlu235Lys: Factor IX with Lysine substituted for Glutamic acid at residue 235. Factor IXGlu245Lys: Factor IX with Lysine substituted for Glutamic acid at residue 245. Factor IXGlu235&245Lys: Factor IX with Lysine substituted for Glutamic acid at residues 235 and 245.) Activated factor IXGlu235Lys bound the fluorescent active site probe, p-aminobenzamidine, normally, while factor XIa cleaved factor IXGlu245Lys and factor IXGlu235&245Lys failed to bind p-aminobenzamidine. Plasma purified factor IX titrated with terbium showed an increase in luminescence; however, factor IXGlu235Lys and factor IXGlu245Lys had no effect on terbium luminescence. Radioimmunoassays indicate that in calcium's absence, factor IXGlu245Lys adopts a conformation similar to normal factor IX in the presence of calcium. By contrast, factor IXGlu245Lys's conformation in the presence of calcium is similar to that of plasma purified factor IX in the absence of calcium.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7740454

  6. Collagen Stimulators: Poly-L-Lactic Acid and Calcium Hydroxyl Apatite.

    PubMed

    Breithaupt, Andrew; Fitzgerald, Rebecca

    2015-11-01

    Over the last decade, many studies of the structural changes observed in the aging face (in bone, fat pads, facial ligaments, muscle, skin) have increased our understanding that facial rejuvenation is more complex and nuanced than simply filling lines and folds or cutting and lifting soft tissue and skin. This, in addition to the many new products introduced to the marketplace over the same period, has fueled the evolution of panfacial rejuvenation and restoration using fillers. This article discusses current techniques used with calcium hydroxylapatite and poly-l-lactic acid to safely and effectively address changes observed in the aging face. PMID:26505542

  7. Collagen Stimulators: Poly-L-Lactic Acid and Calcium Hydroxyl Apatite.

    PubMed

    Breithaupt, Andrew; Fitzgerald, Rebecca

    2015-11-01

    Over the last decade, many studies of the structural changes observed in the aging face (in bone, fat pads, facial ligaments, muscle, skin) have increased our understanding that facial rejuvenation is more complex and nuanced than simply filling lines and folds or cutting and lifting soft tissue and skin. This, in addition to the many new products introduced to the marketplace over the same period, has fueled the evolution of panfacial rejuvenation and restoration using fillers. This article discusses current techniques used with calcium hydroxylapatite and poly-l-lactic acid to safely and effectively address changes observed in the aging face.

  8. Soft-tissue augmentation with hyaluronic acid and calcium hydroxyl apatite fillers.

    PubMed

    Redbord, Kelley Pagliai; Busso, Mariano; Hanke, C William

    2011-01-01

    Soft-tissue augmentation with hyaluronic acid and calcium hydroxyl apatite are among the most widely used minimally invasive cosmetic treatments for the correction of contour deficiencies and wrinkles of the face without the risk, recovery time, and expense of a major surgery. Training and experience in the art and science of fillers is essential for the successful creation of a more youthful and natural appearance. An understanding of the different products, the injection techniques, the indications, and the potential complications of each filler are paramount to success.

  9. Modification of fatty acid profile of cow milk by calcium salts of fatty acids and its use in ice cream.

    PubMed

    Nadeem, Muhammad; Abdullah, Muhammad; Hussain, Imtiaz; Inayat, Saima

    2015-02-01

    This study was conducted to determine the effect of calcium salts of fatty acids (CSFA) on fatty acid profile of milk of "Sahiwal" cows and suitability of milk with modified fatty acids in the formulation of ice cream. Fatty acid profile of cow milk was modified by feeding CSFA to eighteen randomly stratified "Sahiwal" cows of first and early lactation divided into three groups. CSFA were offered at two different levels i.e. T1 (150 g per cow per day) T2 (300 g per cow per day) both treatments were compared with a control (T0) without any addition of calcium salts of fatty acids. Iso caloric and iso nitrogenous feeds were given to both experimental groups and control. Concentrations of short chain fatty acids in T0, T1 and T2 were 9.85 ± 0.48a, 8.8 ± 0.24b and 7.1 ± 0.37c %, respectively and the concentrations of C18:1 and C18:2 increased (P < 0.05) from 27.6 ± 1.32b % to 31.7 ± 1.68a % and 2.15 ± 0.09b % to 2.79 ± 0.05a %, respectively, at T2 level. Incorporation of milk fat of T1 and T2 (modified fatty acids profile) in ice cream did not have any adverse effect on pH, acidity and compositional attributes of ice cream. Viscosity of T1 was 67.94 ± 3.77a as compared to (T0) control 68.75 ± 2.46a (CP). Firmness of experimental samples and control were almost similar (P > 0.05) overall acceptability score of T2 was 7.1 ± 0.28b out of 9 (total score) which was more than 78 ± 2.92 %. It was concluded that CSFA may be successfully incorporated up to T2 level (300 g per cow per day) into the feed of "Sahiwal" cows to produce milk with higher content of unsaturated fatty acids and it may be used in the formulation of ice cream with acceptable sensory characteristics and increased health benefits.

  10. Molecular models of alginic acid: Interactions with calcium ions and calcite surfaces

    NASA Astrophysics Data System (ADS)

    Perry, Thomas D.; Cygan, Randall T.; Mitchell, Ralph

    2006-07-01

    Cation binding by polysaccharides is observed in many environments and is important for predictive environmental modeling, and numerous industrial and food technology applications. The complexities of these cation-organic interactions are well suited for predictive molecular modeling and the analysis of conformation and configuration of polysaccharides and their influence on cation binding. In this study, alginic acid was chosen as a model polymer system and representative disaccharide and polysaccharide subunits were developed. Molecular dynamics simulation of the torsion angles of the ether linkage between various monomeric subunits identified local and global energy minima for selected disaccharides. The simulations indicate stable disaccharide configurations and a common global energy minimum for all disaccharide models at Φ = 274 ± 7°, Ψ = 227 ± 5°, where Φ and Ψ are the torsion angles about the ether linkage. The ability of disaccharide subunits to bind calcium ions and to associate with the (101¯4) surface of calcite was also investigated. Molecular models of disaccharide interactions with calcite provide binding energy differences for conformations that are related to the proximity and residence densities of the electron-donating moieties with calcium ions on the calcite surface, which are controlled, in part, by the torsion of the ether linkage between monosaccharide units. Dynamically optimized configurations for polymer alginate models with calcium ions were also derived.

  11. In vitro biocompatibility of chitosan/hyaluronic acid-containing calcium phosphate bone cements.

    PubMed

    Hesaraki, Saeed; Nezafati, Nader

    2014-08-01

    The need for bone repair has increased as the population ages. In this research, calcium phosphate cements, with and without chitosan (CS) and hyaluronic acid (HA), were synthesized. The composition and morphological properties of cements were evaluated by X-ray diffraction and scanning electron microscopy. The acellular in vitro bioactivity revealed that different apatite morphologies were formed on the surfaces of cements after soaking in simulated body fluid. The in vitro osteoblastic cell biocompatibility of in situ forming cements was evaluated and compared with those of conventional calcium phosphate cements (CPCs). The viability and growth rate of the cells were similar for all CPCs, but better alkaline phosphatase activity was observed for CPC with CS and HA. Calcium phosphate cements supported attachment of osteoblastic cells on their surfaces. Spindle-shaped osteoblasts with developed cytoplasmic membrane were found on the surfaces of cement samples after 7 days of culture. These results reveal the potential of the CPC-CS/HA composites to be used in bone tissue engineering. PMID:24399509

  12. Optimizing facial rejuvenation outcomes by combining poly-L-lactic acid, hyaluronic acid, calcium hydroxylapatite, and neurotoxins: two case studies.

    PubMed

    Lorenc, Z Paul; Daro-Kaftan, Elizabeth

    2014-02-01

    Reversal of the visible signs of facial aging with the use of injectable products as an alternative to surgery has become more popular, with nearly 5 million procedures performed in the United States in 2012. Volume augmentation products, such as hyaluronic acid (HA), calcium hydroxylapatite (CaHA), and poly-L-lactic acid (PLLA), are often used in combination with one another and with neurotoxins for facial rejuvenation because of the complementary modes of action. This article presents 2 case reports involving patientspecific combinations of 2 different HA products, injectable PLLA, and CaHA with incobotulinumtoxinA or abobotulinumtoxinA. The combination of HA, CaHA, PLLA, and neurotoxins has resulted in outstanding outcomes for many patients, with no clinical evidence of increased adverse events secondary to combination therapy. PMID:24509971

  13. Optimizing facial rejuvenation outcomes by combining poly-L-lactic acid, hyaluronic acid, calcium hydroxylapatite, and neurotoxins: two case studies.

    PubMed

    Lorenc, Z Paul; Daro-Kaftan, Elizabeth

    2014-02-01

    Reversal of the visible signs of facial aging with the use of injectable products as an alternative to surgery has become more popular, with nearly 5 million procedures performed in the United States in 2012. Volume augmentation products, such as hyaluronic acid (HA), calcium hydroxylapatite (CaHA), and poly-L-lactic acid (PLLA), are often used in combination with one another and with neurotoxins for facial rejuvenation because of the complementary modes of action. This article presents 2 case reports involving patientspecific combinations of 2 different HA products, injectable PLLA, and CaHA with incobotulinumtoxinA or abobotulinumtoxinA. The combination of HA, CaHA, PLLA, and neurotoxins has resulted in outstanding outcomes for many patients, with no clinical evidence of increased adverse events secondary to combination therapy.

  14. Solid and liquid media for isolating and cultivating acidophilic and acid-tolerant sulfate-reducing bacteria.

    PubMed

    Ňancucheo, Ivan; Rowe, Owen F; Hedrich, Sabrina; Johnson, D Barrie

    2016-05-01

    Growth media have been developed to facilitate the enrichment and isolation of acidophilic and acid-tolerant sulfate-reducing bacteria (aSRB) from environmental and industrial samples, and to allow their cultivation in vitro The main features of the 'standard' solid and liquid devised media are as follows: (i) use of glycerol rather than an aliphatic acid as electron donor; (ii) inclusion of stoichiometric concentrations of zinc ions to both buffer pH and to convert potentially harmful hydrogen sulphide produced by the aSRB to insoluble zinc sulphide; (iii) inclusion of Acidocella aromatica (an heterotrophic acidophile that does not metabolize glycerol or yeast extract) in the gel underlayer of double layered (overlay) solid media, to remove acetic acid produced by aSRB that incompletely oxidize glycerol and also aliphatic acids (mostly pyruvic) released by acid hydrolysis of the gelling agent used (agarose). Colonies of aSRB are readily distinguished from those of other anaerobes due to their deposition and accumulation of metal sulphide precipitates. Data presented illustrate the effectiveness of the overlay solid media described for isolating aSRB from acidic anaerobic sediments and low pH sulfidogenic bioreactors.

  15. Heterogeneous Chemistry of HONO on Liquid Sulfuric Acid: A New Mechanism of Chlorine Activation on Stratospheric Sulfate Aerosols

    NASA Technical Reports Server (NTRS)

    Zhang, Renyi; Leu, Ming-Taun; Keyser, Leon F.

    1996-01-01

    Heterogeneous chemistry of nitrous acid (HONO) on liquid sulfuric acid (H2SO4) Was investigated at conditions that prevail in the stratosphere. The measured uptake coefficient (gamma) of HONO on H2SO4 increased with increasing acid content, ranging from 0.03 for 65 wt % to about 0.1 for 74 wt %. In the aqueous phase, HONO underwent irreversible reaction with H2SO4 to form nitrosylsulfuric acid (NO(+)HSO4(-). At temperatures below 230 K, NO(+)HSO4(-) was observed to be stable and accumulated in concentrated solutions (less than 70 wt % H2SO4) but was unstable and quickly regenerated HONO in dilute solutions (less than 70 wt %). HCl reacted with HONO dissolved in sulfuric acid, releasing gaseous nitrosyl chloride (ClNO). The reaction probability between HCl and HONO varied from 0.01 to 0.02 for 60-72 wt % H2SO4. In the stratosphere, ClNO photodissociates rapidly to yield atomic chlorine, which catalytically destroys ozone. Analysis of the laboratory data reveals that the reaction of HCl with HONO on sulfate aerosols can affect stratospheric ozone balance during elevated sulfuric acid loadings after volcanic eruptions or due to emissions from the projected high-speed civil transport (HSCT). The present results may have important implications on the assessment of environmental acceptability of HSCT.

  16. Chemical and Mineralogical Characterization of Acid-Sulfate Alteration of Basaltic Material on Mauna Kea Volcano, Hawaii: Jarosite and Hydrated Halloysite

    NASA Technical Reports Server (NTRS)

    Graff, Trevor G.; Morris, R. V.; Archilles C. N.; Agresti, D. G.; Ming, D. W.; Hamilton, J. C.; Mertzman, S. A.; Smith, J.

    2012-01-01

    Sulfates have been identified on the martian surface during robotic surface exploration and by orbital remote sensing. Measurements at Meridiani Planum (MP) by the Alpha-Particle X-ray Spectrometer (APXS) and Mossbauer (MB) instruments on the Mars Exploration Rover Opportunity document the presence of a ubiquitous sulfate-rich outcrop (20-40% SO3) that has jarosite as an anhydrous Fe3+-sulfate [1- 3]. The presence of jarosite implies a highly acidic (pH <3) formation environment [4]. Jarosite and other sulfate minerals, including kieserite, gypsum, and alunite have also been identified in several locations in orbital remote sensing data from the MEx OMEGA and MRO CRISM instruments [e.g. 5-8]. Acid sulfate weathering of basaltic materials is an obvious pathway for formation of sulfate-bearing phases on Mars [e.g. 4, 9, 10]. In order to constrain acid-sulfate pathways on Mars, we are studying the mineralogical and chemical manifestations of acid-sulfate alteration of basaltic compositions in terrestrial environments. We have previously shown that acidsulfate alteration of tephra under hydrothermal conditions on the Puu Poliahu cone (summit region of Mauna Kea volcano, Hawaii) resulted in jarosite and alunite as sulfate-bearing alteration products [11-14]. Other, more soluble, sulfates may have formed, but were leached away by rain and melting snow. Acidsulfate processes on Puu Poliahu also formed hematite spherules similar (except in size) to the hematite spherules observed at MP as an alteration product [14]. Phyllosilicates, usually smectite }minor kaolinite are also present as alteration products [13]. We discuss here an occurrence of acid-sulfate alteration on Mauna Kea Volcano (Hawaii). We report VNIR spectra (0.35-2.5 microns ASD spectrometer), Mossbauer spectra (MER-like ESPI backscatter spectrometer), powder XRD (PANalytical), and major element chemical compositions (XRF with LOI and Fe redox) for comparison to similar data acquired or to be acquired by MRO

  17. Enrichment of sulfate-reducing bacteria and resulting mineral formation in media mimicking pore water metal ion concentrations and pH conditions of acidic pit lakes.

    PubMed

    Meier, Jutta; Piva, Angela; Fortin, Danielle

    2012-01-01

    Acid mine drainage sites are extreme environments with high acidity and metal ion concentrations. Under anoxic conditions, microbial sulfate reduction may trigger the formation of secondary minerals as a result of H2S production and pH increase. This process was studied in batch experiments with enrichment cultures from acidic sediments of a pit lake using growth media set at different pH values and containing elevated concentrations of Fe²⁺ and Al³⁺. At initial pH values of 5 and 6, sulfate reduction occurred shortly after inoculation. Sulfate- reducing bacteria affiliated to the genus Desulfosporosinus predominated the microbial communities as shown by 16S rRNA gene analysis performed at the end of the incubation. At initial pH values of 3 and 4, sulfate reduction and cell growth occurred only after an extended lag phase, however, at a higher rate than in the less acidic assays. At the end of the growth phase, enrichments were dominated by Thermodesulfobium spp. suggesting that these sulfate reducers were better adapted to acidic conditions. Iron sulfides in the bulk phase were common in all assays, but specific aluminum precipitates formed in close association with cell surfaces and may function as a detoxification mechanism of dissolved Al species at low pH.

  18. Short-term effect of the combination of hyaluronic acid, chondroitin sulfate, and keratin matrix on early symptomatic knee osteoarthritis

    PubMed Central

    Galluccio, Felice; Barskova, Tatiana; Cerinic, Marco Matucci

    2015-01-01

    Objective In the last years, symptomatic slow-acting drugs for osteoarthritis (SYSADOA) have been vastly studied and have generated considerable interest among clinicians. SYSADOA are generally used as a ground therapy with the main rationale to reduce the consumption of nonsteroidal anti-inflammatory drugs (NSAIDs) and thus limit the related adverse events. Material and Methods In this study, we evaluated the short-term effect of an oral combination of hyaluronic acid, chondroitin sulfate, and keratin matrix on early symptomatic knee osteoarthritis. Forty patients were treated for 1 month and were allowed to assume analgesics or NSAIDs if necessary. Results At 2 months, the mean reduction of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score was 36% (p<0.001), and the mean reduction of the WOMAC pains score was 40% (p<0.001). Only two patients reported a sporadic need to assume analgesics; no patient reported any side effect during the study period. Conclusion This data demonstrates that the oral combination of hyaluronic acid, chondroitin sulfate, and keratin matrix is safe, well tolerated, and shows a rapid action reducing pain and improving joint function and stiffness in early symptomatic knee osteoarthritis.

  19. Bile acid-conjugated chondroitin sulfate A-based nanoparticles for tumor-targeted anticancer drug delivery.

    PubMed

    Lee, Jae-Young; Chung, Suk-Jae; Cho, Hyun-Jong; Kim, Dae-Duk

    2015-08-01

    Chondroitin sulfate A-deoxycholic acid (CSA-DOCA)-based nanoparticles (NPs) were produced for tumor-targeted delivery of doxorubicin (DOX). The hydrophobic deoxycholic acid (DOCA) derivative was conjugated to the hydrophilic chondroitin sulfate A (CSA) backbone via amide bond formation, and the structure was confirmed by (1)H-nuclear magnetic resonance (NMR) analysis. Loading the DOX to the CSA-DOCA NPs resulted in NPs with an approximately 230nm mean diameter, narrow size distribution, negative zeta potential, and relatively high drug encapsulation efficiency (up to 85%). The release of DOX from the NPs exhibited sustained and pH-dependent release profiles. The cellular uptake of DOX from the CSA-DOCA NPs in CD44 receptor-positive human breast adenocarcinoma MDA-MB-231 cells was reduced when co-treated with free CSA, indicating the interaction between CSA and the CD44 receptor. The lower IC50 value of DOX from the CSA-DOCA NPs compared to the DOX solution was also probably due to this interaction. Moreover, the ability of the developed NPs to target tumors could be inferred from the in vivo and ex vivo near-infrared fluorescence (NIRF) imaging results in the MDA-MB-231 tumor-xenografted mouse model. Both passive and active strategies appear to have contributed to the in vivo tumor targetability of the CSA-DOCA NPs. Therefore, these CSA-DOCA NPs could further be developed into a theranostic nanoplatform for CD44 receptor-positive cancers.

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false D-Glucuronic acid, polymer with 6...-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium... identified as D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium...

  1. Reduced Endoplasmic Reticulum Luminal Calcium Links Saturated Fatty Acid-Mediated Endoplasmic Reticulum Stress and Cell Death in Liver Cells

    PubMed Central

    Wei, Yuren; Wang, Dong; Gentile, Christopher L.; Pagliassotti, Michael J.

    2010-01-01

    Chronic exposure to elevated free fatty acids, in particular long chain saturated fatty acids, provokes endoplasmic reticulum (ER) stress and cell death in a number of cell types. The perturbations to the ER that instigate ER stress and activation of the unfolded protein in response to fatty acids in hepatocytes have not been identified. The present study employed H4IIE liver cells and primary rat hepatocytes to examine the hypothesis that saturated fatty acids induce ER stress via effects on ER luminal calcium stores. Exposure of H4IIE liver cells and primary hepatocytes to palmitate and stearate reduced thapsigargin-sensitive calcium stores and biochemical markers of ER stress over similar time courses (6h). These changes preceded cell death, which was only observed at later time points (16h). Co-incubation with oleate prevented the reduction in calcium stores, induction of ER stress markers and cell death observed in response to palmitate. Inclusion of calcium chelators, BAPTA-AM or EGTA, reduced palmitate- and stearate-mediated enrichment of cytochrome c in post-mitochondrial supernatant fractions and cell death. These data suggest that redistribution of ER luminal calcium contributes to long chain saturated fatty acid-mediated ER stress and cell death. PMID:19444596

  2. Formation of calcium carbonate films on chitosan substrates in the presence of polyacrylic acid

    SciTech Connect

    He, Linghao; Xue, Rui; Song, Rui

    2009-05-15

    In this investigation, chitosan membranes with different surface average degrees of deacetylation (DA) are prepared and then are employed as the support matrix to culture calcium carbonate (CaCO{sub 3}). In the presence of high concentration of polyacrylic acid (PAA), the CaCO{sub 3} films obtained on the surface of all chitosan films mainly consisted of vaterite, which suggests the presence of bulk PAA plays an overwhelming part in stabilizing the vaterite. As a comparison, the influences of active groups indicate that only in case of low concentration PAA the thin CaCO{sub 3} films grown on chitosan with 8% DA mainly consisted of vaterite owing to the strong nucleation ability of -NH{sub 2} group, whereas, for those grown on chitosan with 80% DA the CaCO{sub 3} films mainly consisted of aragonite. A more complex scenario revealed that in the case of intermediate concentration of PAA the formed polymorphs behave as mixtures of vaterite and aragonite. - Graphical abstract: Chitosan membranes with different degrees of deacetylation (DA) are employed as support to culture calcium carbonate (CaCO{sub 3}). In high concentration of polyacrylic acid (PAA), the CaCO{sub 3} films obtained consisted of vaterite. However, the CaCO{sub 3} film grown on chitosan with 8% DA mainly consisted of vaterite as opposed to aragonite for chitosan with 8% DA. The schematic presentation of the formation of calcium carbonate on chitosan films with different degrees of acetylation in the presence of PAA with low-, mid- and high concentrations.

  3. Efficacy of levulinic acid-sodium dodecyl sulfate against Encephalitozoon intestinalis, Escherichia coli O157:H7, and Cryptosporidium parvum.

    PubMed

    Ortega, Ynes R; Torres, Maria P; Tatum, Jessica M

    2011-01-01

    Foodborne parasites are characterized as being highly resistant to sanitizers used by the food industry. In 2009, a study reported the effectiveness of levulinic acid in combination with sodium dodecyl sulfate (SDS) in killing foodborne bacteria. Because of their innocuous properties, we studied the effects of levulinic acid and SDS at various concentrations appropriate for use in foods, on the viability of Cryptosporidium parvum and Encephalitozoon intestinalis. The viability of Cryptosporidium and E. intestinalis was determined by in vitro cultivation using the HCT-8 and RK-13 cell lines, respectively. Two Escherichia coli O157:H7 isolates were also used in the present study: strain 932 (a human isolate from a 1992 Oregon meat outbreak) and strain E 0018 (isolated from calf feces). Different concentrations and combinations of levulinic acid and SDS were tested for their ability to reduce infectivity of C. parvum oocysts (10(5)), E. intestinalis spores (10(6)), and E. coli O157:H7 (10(7)/ml) when in suspension. Microsporidian spores were treated for 30 and 60 min at 20 ± 2°C. None of the combinations of levulinic acid and SDS were effective at inactivating the spores or oocysts. When Cryptosporidium oocysts were treated with higher concentrations (3% levulinic acid-2% SDS and 2% levulinic acid-1% SDS) for 30, 60, and 120 min, viability was unaffected. E. coli O157:H7, used as a control, was highly sensitive to the various concentrations and exposure times tested. SDS and levulinic acid alone had very limited effect on E. coli O157:H7 viability, but in combination they were highly effective at 30 and 60 min of incubation. In conclusion, Cryptosporidium and microsporidia are not inactivated when treated for various periods of time with 2% levulinic acid-1% SDS or 3% levulinic acid-2% SDS at 20°C, suggesting that this novel sanitizer cannot be used to eliminate parasitic contaminants in foods. PMID:21219777

  4. Dissolution mechanism of calcium apatites in acids: A review of literature

    PubMed Central

    Dorozhkin, Sergey V

    2012-01-01

    Eight dissolution models of calcium apatites (both fluorapatite and hydroxyapatite) in acids were drawn from the published literature, analyzed and discussed. Major limitations and drawbacks of the models were conversed in details. The models were shown to deal with different aspects of apatite dissolution phenomenon and none of them was able to describe the dissolution process in general. Therefore, an attempt to combine the findings obtained by different researchers was performed which resulted in creation of the general description of apatite dissolution in acids. For this purpose, eight dissolution models were assumed to complement each other and provide the correct description of the specific aspects of apatite dissolution. The general description considers all possible dissolution stages involved and points out to some missing and unclear phenomena to be experimentally studied and verified in future. This creates a new methodological approach to investigate reaction mechanisms based on sets of affine data, obtained by various research groups under dissimilar experimental conditions. PMID:25237611

  5. Biomediated Precipitation of Calcium Carbonate in a Slightly Acidic Hot Spring

    NASA Astrophysics Data System (ADS)

    Jiang, L.

    2015-12-01

    A slightly acidic hot spring named "Female Tower" (T=73.5 °C, pH=6.64) is located in the Jifei Geothermal Field, Yunnan Province, Southwest China. The precipitates in the hot spring are composed of large amounts of calcite, aragonite, and sulfur. Scanning electron microscopy (SEM) analyses revealed that the microbial mats were formed of various coccoid, rod-shaped, and filamentous microbes. Transmission electron microscopy (TEM) showed that the intracellular sulfur granules were commonly associated with these microbes. A culture-independent molecular phylogenetic analysis demonstrated that the majority of the bacteria in the spring were sulfur-oxidizing bacteria. In the spring water, H2S concentration was up to 60 ppm, while SO42- concentration was only about 10 ppm. We speculated that H2S might be utilized by sulfur-oxidizing bacteria in this hot spring water, leading to the intracellular formation of sulfur granules. In the meantime, this reaction increased the pH in the micron-scale microdomains, which fostered the precipitation of calcium carbonate in the microbial mats. The results of this study indicated that the sulfur-oxidizing bacteria could play an important role in calcium carbonate precipitation in slightly acidic hot spring environments.

  6. Performance of calcium deficient hydroxyapatite-polyglycolic acid composites: an in vitro study.

    PubMed

    Dunne, Nicholas; Jack, Valerie; O'Hara, Rochelle; Farrar, David; Buchanan, Fraser

    2010-08-01

    The strategic incorporation of bioresorbable polymeric additives to calcium-deficient hydroxyapatite cement may provide short-term structural reinforcement and modify the modulus to closer match bone. The longer-term resorption properties may also be improved, creating pathways for bone in-growth. The aim of this study was to investigate the resorption process of a calcium phosphate cement system containing either in polyglycolic acid tri-methylene carbonate particles or polyglycolic acid fibres. This was achieved by in vitro aging in physiological conditions (phosphate buffered solution at 37 degrees C) over 12 weeks. The unreinforced CPC exhibited an increase in compressive strength at 12 weeks, however catastrophic failure was observed above a critical loading. The fracture behaviour of cement was improved by the incorporation of PGA fibres; the cement retained its cohesive structure after critical loading. Gravimetric analysis and scanning electron microscopy showed a large proportion of the fibres had resorbed after 12 weeks allowing for the increased cement porosity, which could facilitate cell infiltration and faster integration of natural bone. Incorporating the particulate additives in the cement did not provide any mechanism for mechanical property augmentation or did not demonstrate any appreciable level of resorption after 12 weeks.

  7. Biomediated Precipitation of Calcium Carbonate and Sulfur in a Faintly Acidic Hot Spring

    NASA Astrophysics Data System (ADS)

    Jiang, L.; Peng, X.; Qiao, H.

    2014-12-01

    A faintly acidic hot spring named "female Tower" (T=73.5 ℃, pH=6.64 ) is located in the Jifei Geothermal Field,Yunnan province, Southwest China. The precipitates in the hot spring are composed of large amounts of calcite and sulfur, as reveals by XRD analysis. Scanning electron microscopy (SEM) analysis show the microbial mats are formed of various coccoid, rod and filamentous microbes. Transmission electron microscopy (TEM) analysis show that intracellular sulfur granules are commonly associated with these microbes. Energy dispersive X-ray spectrometer (EDS) analysis shows that the surface of microbes are mainly composed of Ca, C, O and S. A culture-independent molecular phylogenetic analysis demonstrates the majority of bacteria in the spring are sulfur-oxidizing bacteria. In the spring water, H2S concentration was up to 60 ppm, while SO42- concentration was only about 10 ppm. We suggest that H2S might be utilized by sulfur-oxidizing bacteria in this hot spring water, leading to the formation of sulfur granules intracellularly and extracellularly. In the meantime, this reaction increases the pH in ambient environments, which fosters the precipitation of calcium carbonate precipitation in the microbial mats. This study suggests that the sulfur-oxidizing bacteria could play an important role in calcium carbonate precipitation in faintly acidic hot spring environments.

  8. Formation of a Phyllosilicate-, K-feldspar-, and Sulfate-Bearing Hematite Ridge on Mauna Kea Volcano, Hawaii, Under Hydrothermal, Acid-Sulfate Conditions: Process and Mineralogical Analog for the Hematite Ridge on Mt. Sharp, Gale Crater, Mars.

    NASA Astrophysics Data System (ADS)

    Ming, D. W.; Morris, R. V.; Adams, M. E.; Catalano, J. G.; Graff, T. G.; Arvidson, R. E.; Guinness, E. A.; Hamilton, J. C.; Mertzman, S. A.; Fraeman, A.

    2015-12-01

    The Mars Science Laboratory rover Curiosity is currently moving upslope on Mt. Sharp in Gale Crater toward a hematite-bearing ridge. This hematite exposure was originally detected in CRISM spectra and subsequently mapped as part of a ~200 m wide, 6.5 km long ridge extending roughly parallel to the base of Mt. Sharp. CRISM spectra in the region suggest that hematite, smectite, and hydrated sulfates occur as secondary phases in lower layers of Mt. Sharp, separated by an unconformity from overlying anhydrous strata. A potential process and mineralogical analog is a hematite-bearing and weathering-resistant stratum (ridge) is exposed on the Puu Poliahu cinder cone on Mauna Kea (MK) volcano, Hawaii. The MK ridge is the product of hydrothermal alteration of basaltic precursors under acid-sulfate conditions. We are acquiring chemical and mineralogical (VNIR, Mid-IR, and backscatter Moessbauer spectroscopy, and transmission XRD) data on the MK ridge area that correspond to rover and orbiting spacecraft measurements at Gale Crater and elsewhere. The hematite-bearing stratum does not have detectable sulfate minerals by XRD, and hematite is variably present as up to mm-sized black crystals which, together with associated trioctahedral smectite and K-feldspar (from XRD), imply hydrothermal conditions. Adjacent to the MK hematite-bearing stratum are sulfates (jarosite and alunite) that are evidence for aqueous alteration under acid-sulfate conditions, and more soluble sulfates are absent but such phases would not persist if formed because of annual precipitation. Dioctahedral smectite is associated with red hematite and alunite-rich samples. The black and red hematite zones have the highest and lowest MgO/Al2O3 and K2O/Na2O ratios, respectively. Hematite, smectite, jarosite, and K-feldspar have been detected by Curiosity XRD downslope from the Mt. Sharp hematite ridge. MK field work and samples were obtained with PISCES partnership and OMKM, MKMB, BLNR, and KKMC permissions.

  9. Ascorbic acid ameliorates oxidative stress and inflammation in dextran sulfate sodium-induced ulcerative colitis in mice

    PubMed Central

    Yan, Haiyan; Wang, Hongjuan; Zhang, Xiaoli; Li, Xiaoqin; Yu, Jing

    2015-01-01

    Ascorbic acid (AA) has been shown to exert beneficial effects, including mitigating oxidative stress and inhibiting inflammation. However, the preventative effect of vitamin C in chronic inflammatory diseases such as inflammatory bowel disease (IBD) remains unclear. In our study, we investigated the anti-inflammatory effects of AA and possible mechanism involved in inhibiting dextran sulfate sodium (DSS)-induced ulcerative colitis in mice. Male C57BL/6 mice were randomly divided to three groups: control group, DSS group, and DSS plus ascorbic acid treated group. Several clinical and inflammatory parameters as well as oxidative stress were evaluated. The results demonstrated that ascorbic acid significantly reduced clinical signs, inflammatory cytokines, myeloperoxidase (MPO) and malonaldehyde (MDA) activities, whereas the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were increased in DSS-induced mice. In addition, ascorbic acid was capable of inhibiting NF-κB, COX-2 and iNOS expression in the colonic. Taken together, these findings suggest that ascorbic acid contributes to the reduction of oxidative stress and inflammatory response in DSS-induced colitis and exerts the potential to prevent and clinical treatment of inflammatory bowel disease. PMID:26884937

  10. Effect of side chain length on bile acid conjugation: glucuronidation, sulfation and coenzyme A formation of nor-bile acids and their natural C24 homologs by human and rat liver fractions.

    PubMed

    Kirkpatrick, R B; Green, M D; Hagey, L R; Hofmann, A F; Tephly, T R

    1988-01-01

    The effect of side chain length on bile acid conjugation by human and rat liver fractions was examined. The rate of conjugation with glucuronic acid, sulfate and coenzyme A of several natural (C24) bile acids was compared with that of their corresponding nor-bile acids. The rate of coenzyme A ester formation by nor-bile acids was much lower than that of the natural bile acids. In human liver microsomes, the rate of coenzyme A formation was less than 8% of the rate for the corresponding C24 bile acid. Rat liver microsomes formed the coenzyme A ester of nor-bile acids less than 20% of the rate of their corresponding C24 homologs. Glucuronidation rates were greater than sulfation rates in both species. With human liver microsomes, nor-bile acids were glucuronidated more rapidly than their corresponding C24 homologs, whereas with rat liver microsomes the reverse was true. Purified 3 alpha-OH androgen UDP-glucuronyltransferase catalyzed the glucuronidation of both nor-bile acids and bile acids. Human liver cytosol sulfated nor-bile acids more slowly than the corresponding bile acids. Rat liver cytosol, however, sulfated nor-bile acids more rapidly than the corresponding bile acids. The highest rate was seen with lithocholylglycine. The results indicate that the novel biotransformation of nor-bile acids seen in vivo--sulfation and glucuronidation rather than amidation--is most likely explained as a consequent of defective amidation, to which the rate of coenzyme A formation contributes. Thus, side chain and nuclear structures as well as species differences in conjugating enzyme activity are determinants of the pattern of bile acid biotransformation by the mammalian liver.

  11. Evidence for Siliceous Deposits Formed by Acid-Sulfate Alteration at Home Plate in Gusev Crater, Mars

    NASA Astrophysics Data System (ADS)

    Morris, R. V.; Ming, D. W.; Gellert, R.; Yen, A. S.; Clark, B. C.; Ruff, S. W.; Graff, T. G.; Arvidson, R. E.; Squyres, S. W.; Science Teams, T.

    2007-12-01

    The Alpha Particle X-ray Spectrometer (APXS) instrument on the Mars Exploration Rover (MER) Spirit measured three targets on or adjacent to Home Plate in Gusev Crater that have unusually high SiO2 concentrations (68 to 91%), unusually low FeO concentrations (1 to 7%, with total Fe as FeO), and unusually high TiO2/FeO ratios (0.2 to 1.2 by weight). Two targets are high albedo soil (Gertrude Weise) exposed by the rover wheels (Kenosha Comets and Lefty Ganote), and one target is a rock (Fuzzy Smith). Kenosha Comets has the highest SiO2 concentration, lowest FeO concentration, and highest TiO2/FeO ratio. Mineralogical evidence from the MER Miniature Thermal Emission Spectrometer (Mini-TES) suggests that high proportions of amorphous (non- crystalline) SiO2 account for the high SiO2 concentration of Gertrude Weise. Mini-TES data were not acquired for Fuzzy Smith. The spectral evidence for amorphous SiO2 includes deep emissivity minima near 9 and 21 microns. Amorphous SiO2 is typically characterized by a shoulder near 8 microns, but the Gertrude Weise spectra are instead characterized by a well-defined emissivity minimum. The difference is attributed to scattering and/or geometric effects. The chemistry of Gertrude Weise and Fuzzy Smith is very similar to that for a tholeiitic basaltic rock altered under acid-sulfate conditions in a fumarolic (hydrothermal) environment on Kilauea Volcano (Hawaii). The terrestrial acid sulfate alteration resulted in compositions having about 62 to 91% SiO2, 1 to 8% FeO, and 0.3 to 5 TiO2/FeO. The SiO2 and TiO2 are passively enriched while all other major elements are removed by leaching. XRD analysis shows that SiO2 and TiO2 are present as amorphous SiO2 (opal-A) and anatase, respectively. Alunite is also present. Thermal emission spectra of the Kilauea rock obtained from its exterior surface and from 500-1000 micron and <150 micron powders derived by grinding and sieving are all characterized by the emissivity features at 8, 9, and 21

  12. Measurement of the water cycle in mixed ammonium acid sulfate particles

    NASA Astrophysics Data System (ADS)

    Spann, J. F.; Richardson, C. B.

    A single ammonium-hydrogen-sulfate particle is levitated in an evacuated quadrupole trap at room temperature and the temperature of an attached tube containing bulk water is slowly cycled introducing then removing water vapor. With increasing pressure the particle dissolves in stages, then grows as a solution droplet by water absorption. With decreasing pressure the droplet supersaturates, crystallizes, then dehydrates completely to return to its initial state. Particle mass, and thus composition, is measured continuously with an electrostatic balance. Twenty-six cycles were studied as solute composition ranged from ammonium bisulfate through letovicite to ammonium sulfate in roughly equal steps. Composition was changed in situ by reaction with ammonia at low partial pressure. With solute composition characterized by x = [NH 4]/[SO 4], deliquescence was found to occur at water activity aw = 0.394-0.029 ( x- 1) for 1 ⩽ x < 1.5 and aw = 0.710-0.023( x-1.5) for 1.5 ⩽ x < 2. Particle growth occurs at deliquescence and subsequently is in excellent agreement with that predicted in a model proposed by Tang for dissolution of a two-component mixed solute. Water activities of the solution droplets are measured up to aw = 0.9. The results are compared with those predicted by the Zdanovskii-Stokes-Robinson method of interpolation from binary data and with those obtained using the mixing rule of Meissner and Kusik. Particle crystallization from supersaturated solution is analyzed thermodynamically using measured water activities, the Gibbs-Duhem equation, and classical nucleation theory. The specific free energy barrier to crystallization, ΔG/ n, is found to increase from near zero to 0.04 eV as composition ranges from x = 1 to 2, where n is the number of formula units in the critical nucleus. New phase diagrams are presented and used to discuss the dynamics of mixed sulfate particles in the atmosphere.

  13. [EXPERIENCE OF USE OF BLEMAREN® IN THE TREATMENT OF PATIENTS IN URIC ACID AND CALCIUM OXALATE UROLITHIASIS].

    PubMed

    Konstantinova, O V; Yanenko, E K

    2015-01-01

    154 patients with urolithiasis were under outpatient observation for 2-8 years. Among them there were 76 women and 78 men aged 21-66 years, of which 46 patients with uric acid urolithiasis, and 88--with calcium oxalate urolithiasis. Treatment of patients was carried out systematically, depending on their condition. Indications for the application of Blemaren® included the presence of uric acid stones, uric acid and/or oxalate crystalluria. The duration of treatment was 6.1 months. The dosage of the drug varied from 6 to 18 g per day and was selected individually, depending on the purpose of the appointment of Blemaren®. Reduction of the urine pH to 6.2- 6.8-7.2 was the criterion for properly selected dose. To dissolve uric acid stones in the presence of hyperuricemia and/or hyperuricuria, Blemaren® was administered in combination with allopurinol at a dose of 0.1 g 3-4 times a day. Besides pharmacotherapy, treatment included diet therapy. It was found that the morning urine pH in urate urolithiasis is sustainable and has a range of 5.0-6.0, in 80.4% of cases--range of 5.0-5.5. In calcium oxalate urolithiasis this parameter is also stable and has a range of 5.0-6.7, in 82.9% of cases--range of 5.5-6.0. Optimal urine pH to eliminate uric acid and oxalate crystalluria in patients with uric acid and calcium oxalate urolithiasis is the interval of 6.2-6.4. It was shown that Blemaren® is a highly effective agent for treatment and prevention of uric acid and calcium oxalate crystalluria in calcium oxalate and uric acid urolithiasis. Further, its effectiveness in dissolving of uric acid stones in the absence of an infectious inflammatory process is 82.3%. PMID:26859932

  14. Efficacy of a levulinic acid plus sodium dodecyl sulfate-based sanitizer on inactivation of human norovirus surrogates.

    PubMed

    Cannon, Jennifer L; Aydin, Ali; Mann, Amy N; Bolton, Stephanie L; Zhao, Tong; Doyle, Michael P

    2012-08-01

    Human noroviruses are the most common etiologic agent of foodborne illness in the United States. The inability to culture human noroviruses in the laboratory necessitates the use of surrogate viruses such as murine norovirus (MNV-1) and feline calicivirus (FCV) for inactivation studies. In this study, a novel sanitizer of organic acid (levulinic acid) plus the anionic detergent sodium dodecyl sulfate (SDS) was evaluated. Viruses were treated with levulinic acid (0.5 to 5%), SDS (0.05 to 2%), or combinations of levulinic acid plus SDS (1:10 solution of virus to sanitizer). MNV-1 inoculated onto stainless steel also was treated with a 5% levulinic acid plus 2% SDS liquid or foaming solution. Log reductions of viruses were determined with a plaque assay. Neither levulinic acid nor SDS alone were capable of inactivating MNV-1 or FCV, resulting in a ≤0.51-log reduction of the infectious virus titer. However, the combination of 0.5% levulinic acid plus 0.5% SDS inactivated both surrogates by 3 to 4.21 log PFU/ml after 1 min of exposure. Similarly, MNV-1 inoculated onto stainless steel was reduced by >1.50 log PFU/ml after 1 min and by >3.3 log PFU/ml after 5 min of exposure to a liquid or foaming solution of 5% levulinic acid plus 2% SDS. The presence of organic matter (up to 10%) in the virus inoculum did not significantly affect sanitizer efficacy. The fact that both of the active sanitizer ingredients are generally recognized as safe to use as food additives by the U.S. Food and Drug Administration further extends its potential in mitigating foodborne disease. PMID:22856583

  15. Effects of gibberellic Acid, calcium, kinetic, and ethylene on growth and cell wall composition of pea epicotyls.

    PubMed

    Mondal, M H

    1975-11-01

    The influence of gibberellic acid (GA), calcium, kinetin, and ethylene on growth and cell-wall composition of decapitated pea epicotyls (Pisum sativum L. var. Alaska) was investigated. Calcium, kinetin, and ethylene each caused an inhibition of GA-induced elongation of pea stems. Gibberellic acid did not reverse the induction of swelling by Ca(2+), kinetin, or ethylene. Both Ca(2+) and ethylene significantly inhibited the stimulatory effects of GA on the formation of residual wall material. Although GA promoted the development of walls relatively low in pectic substances and pectic uronic acid, Ca(2+), kinetin, and ethylene favored the formation of walls rich in these constituents. Calcium, kinetin, and GA, alone or in combination, had no effect on the production of ethylene by pea epicotyls. PMID:16659357

  16. Solubility of calcium salts of unconjugated and conjugated natural bile acids.

    PubMed

    Gu, J J; Hofmann, A F; Ton-Nu, H T; Schteingart, C D; Mysels, K J

    1992-05-01

    The approximate solubility products of the calcium salts of ten unconjugated bile acids and several taurine conjugated bile acids were determined. The formation of micelles, gels, and/or precipitates in relation to Ca2+,Na+, and bile salt concentration was summarized by "phase maps." Because the ratio of Ca2+ to bile salt in the precipitates was ca. 1:2, and the activity of Ca2+ but not that of bile salt (BA-) could be measured, the ion product of aCa2+ [BA-]2 was calculated. The ion product (= Ksp) ranged over nine orders of magnitude and the solubility thus ranged over three orders of magnitude; its value depended on the number and orientation of the hydroxyl groups in the bile acid. Ion products (in units of 10(-9) mol/l)3 were as follows: cholic (3 alpha OH,7 alpha OH,12 alpha OH) 640; ursocholic (3 alpha OH,7 beta OH,12 alpha OH) 2300; hyocholic (3 alpha OH,6 alpha OH,7 alpha OH) 11; ursodeoxycholic (3 alpha OH,7 beta OH) 91; chenodeoxycholic (3 alpha OH,7 alpha OH) 10; deoxycholic (3 alpha OH,12 alpha OH) 1.5; 12-epideoxycholic (lagodeoxycholic, 3 alpha OH,12 beta OH) 2.2; hyodeoxycholic (3 alpha OH,6 alpha OH) 0.7; and lithocholic (3 alpha OH) 0.00005. The critical micellization temperature of the sodium salt of murideoxycholic acid (3 alpha OH,6 beta OH) was greater than 100 degrees C, and its Ca2+ salt was likely to be very insoluble. Taurine conjugates were much more soluble than their corresponding unconjugated derivatives: chenodeoxycholyltaurine, 384; deoxycholyltaurine, 117; and cholyltaurine, greater than 10,000. Calcium salts of unconjugated bile acids precipitated rapidly in contrast to those of glycine conjugates which were metastable for months. Thus, hepatic conjugation of bile acids with taurine or glycine not only enhances solubility at acidic pH, but also at Ca2+ ion concentrations present in bile and intestinal content.

  17. Purification and characterisation of a glutamic acid-containing peptide with calcium-binding capacity from whey protein hydrolysate.

    PubMed

    Huang, Shun-Li; Zhao, Li-Na; Cai, Xixi; Wang, Shao-Yun; Huang, Yi-Fan; Hong, Jing; Rao, Ping-Fan

    2015-02-01

    The bioavailability of dietary ionised calcium is affected by intestinal basic environment. Calcium-binding peptides can form complexes with calcium to improve its absorption and bioavailability. The aim of this study was focused on isolation and characterisation of a calcium-binding peptide from whey protein hydrolysates. Whey protein was hydrolysed using Flavourzyme and Protamex with substrate to enzyme ratio of 25:1 (w/w) at 49 °C for 7 h. The calcium-binding peptide was isolated by DEAE anion-exchange chromatography, Sephadex G-25 gel filtration and reversed phase high-performance liquid chromatography (RP-HPLC). A purified peptide of molecular mass 204 Da with strong calcium binding ability was identified on chromatography/electrospray ionisation (LC/ESI) tandem mass spectrum to be Glu-Gly (EG) after analysis and alignment in database. The calcium binding capacity of EG reached 67·81 μg/mg, and the amount increased by 95% compared with whey protein hydrolysate complex. The UV and infrared spectrometer analysis demonstrated that the principal sites of calcium-binding corresponded to the carboxyl groups and carbonyl groups of glutamic acid. In addition, the amino group and peptide amino are also the related groups in the interaction between EG and calcium ion. Meanwhile, the sequestered calcium percentage experiment has proved that EG-Ca is significantly more stable than CaCl2 in human gastrointestinal tract in vitro. The findings suggest that the purified dipeptide has the potential to be used as ion-binding ingredient in dietary supplements.

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

    PubMed Central

    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

  19. 40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl...

  20. 40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl...

  1. 40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl...

  2. 40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl...

  3. 40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids