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Sample records for alkalinity calcium magnesium

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

    SciTech Connect

    Gillette, D.A. ); Stensland, G.J.; Williams, A.L.; Barnard, W.; Gatz, D. ); Sinclair, P.C. ); Johnson, T.C. )

    1992-12-01

    Models of dust emissions by wind erosion (including winds associated with regional activity as well as dust devils) and vehicular disturbances of unpaved roads were developed, calibrated, and used to estimate alkaline dust emissions from elemental soil and road composition data. Emissions from tillage of soils were estimated form the work of previous researchers. The area of maximum dust production by all of those sources is the area of the old Dust Bowl' of the 1930s (the panhandles of Texas and Oklahoma, eastern New Mexico and Colorado, and western Kansas). The areas of maximum alkaline dust production are the arid southwest, the Dust Bowl,' and the midwestern-mideastern states from Iowa to Pennsylvania. Our calculations show that calcium is the dominant alkaline element produced by open sources' (sources too great in extent to be controlled by enclosure or ducting). Although the largest dust mass source is wind erosion (by winds associated with regional activity and convective activity), the largest producer of the alkaline component is road dust because the abundance of alkaline materials in road coverings (which include crushed limestone) is significantly higher than for soils. Comparing the above estimated sources of alkaline material with inventories of SO[sub 2] and NO[sub x] emissions by previous investigators gives the rough approximation that alkaline emission rates are of the order of the SO[sub 2] + NO[sub x] emissions in the western United States and that they are much smaller than SO[sub 2] + NO[sub x] in the eastern United States. This approximation is substantiated by data on Ca/(SO[sub 4] + NO[sub 3]) for wet deposition for National Atmospheric Deposition Program sites. 53 refs., 9 figs., 2 tabs.

  2. Major Minerals - Calcium, Magnesium, Phosphorus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calcium, magnesium and phosphorus are essential elements critically important for the function of the musculoskeletal system, including the formation and transduction of energy and the maintenance of healthy bone. The major calcium concern for physically active healthy middle-aged adults is to consu...

  3. Magnesium/Calcium Competition at Excitable Membranes.

    ERIC Educational Resources Information Center

    Belzer, Bill; Fry, Panni

    1998-01-01

    Considers some consequences of altering intracellular calcium supply by magnesium concentration changes. Focuses on using this procedure as an exercise with allied health students as they witness therapeutic uses of magnesium and other calcium entry inhibitors. (DDR)

  4. Calcium, magnesium, and potassium in food

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The biochemical and physiological functions and consequences of deficient intakes, which show the nutritional importance of calcium, magnesium and potassium for humans, are reviewed. The dietary recommendations and food sources for these essential mineral elements for humans are presented. Factors t...

  5. The Association Between Calcium, Magnesium, and Ratio of Calcium/Magnesium in Seminal Plasma and Sperm Quality.

    PubMed

    Liang, Hong; Miao, Maohua; Chen, Jianping; Chen, Kanglian; Wu, Bin; Dai, Qi; Wang, Jian; Sun, Fei; Shi, Huijuan; Yuan, Wei

    2016-11-01

    The study aimed to examine the relationships between calcium, magnesium, and calcium/magnesium ratio in semen plasma and sperm quality. It was a cross-sectional study based on a program aiming at promoting the reproductive health in less-developed areas. A total of 515 men aged between 18 and 55 years provided semen specimens at family planning clinics in Sandu County, Guizhou Province, China. Total calcium and magnesium concentrations in semen plasma were measured with flame atomic absorption spectrometry. Sperm quality, including sperm motility and concentration, was evaluated by using a computer-assisted sperm analysis method. The medians of seminal plasma calcium, magnesium, and zinc concentrations were 9.61, 4.41, and 2.23 mmol/l, respectively. Calcium concentration and calcium/magnesium ratio were negatively associated with sperm concentrations (β = -0.47, P = 0.0123 for calcium; β = -0.25, P = 0.0393 for calcium/magnesium ratio) after adjusting for zinc and other covariates. In stratified analyses, the association between calcium and sperm concentrations only persisted among subjects with a calcium/magnesium ratio of ≤2.5 (β = -0.71, P = 0.0268). In the same stratum, magnesium was associated with increased sperm concentration (β = 0.73, P = 0.0386). Among subjects with a calcium/magnesium ratio of >2.5, neither calcium nor magnesium was associated with sperm concentration. In conclusion, total calcium and magnesium concentrations were associated with sperm concentration among subjects with a lower calcium/magnesium ratio. The calcium and magnesium ratio had a modifying effect on the associations of calcium and magnesium with sperm concentration.

  6. Ascorbic acid, calcium, phosphorus and magnesium intake variations: effects on calcium, phosphorus and magnesium utilization by human adults

    SciTech Connect

    Kies, C.; Brennan, M.A.; Parks, S.K.; Stauffer, D.J.; Wang, H.Y.; Young, S.F.; Fox, H.M.

    1986-03-01

    The objective of the study was to determine the effects of feeding two levels of ascorbic acid, calcium, phosphorus, magnesium and ascorbic acid on the apparent utilization of calcium, phosphorus and magnesium by healthy, human adult subjects. During 4 randomly-arranged experimental periods of 7 days each, a laboratory-controlled diet alone or with supplements of ascorbic acid, dicalcium phosphate or magnesium oxide was fed to the 18 subjects. Results indicated that ascorbic acid supplementation tended to reduce urinary phosphorus loss and to slightly increase fecal phosphorus loss so that overall phosphorus balances became more positive. Conversely, under these conditions, urinary calcium losses were little affected but fecal calcium losses were increased resulting in an overall decrease in calcium balance with ascorbic acid supplementation. Ascorbic acid supplementation resulted in decreased urine and fecal losses of magnesium and more positive magnesium balances. Magnesium supplementation resulted in more positive calcium and phosphorus balances as did calcium phosphate supplementation on magnesium balance.

  7. Development of magnesium calcium phosphate biocement for bone regeneration

    PubMed Central

    Jia, Junfeng; Zhou, Huanjun; Wei, Jie; Jiang, Xin; Hua, Hong; Chen, Fangping; Wei, Shicheng; Shin, Jung-Woog; Liu, Changsheng

    2010-01-01

    Magnesium calcium phosphate biocement (MCPB) with rapid-setting characteristics was fabricated by using the mixed powders of magnesium oxide (MgO) and calcium dihydrogen phosphate (Ca(H2PO4)2·H2O). The results revealed that the MCPB hardened after mixing the powders with water for about 7 min, and the compressive strength reached 43 MPa after setting for 1 h, indicating that the MCPB had a short setting time and high initial mechanical strength. After the acid–base reaction of MCPB containing MgO and Ca(H2PO4)2·H2O in a molar ratio of 2 : 1, the final hydrated products were Mg3(PO4)2 and Ca3(PO4)2. The MCPB was degradable in Tris–HCl solution and the degradation ratio was obviously higher than calcium phosphate biocement (CPB) because of its fast dissolution. The attachment and proliferation of the MG63 cells on the MCPB were significantly enhanced in comparison with CPB, and the alkaline phosphatase activity of MG63 cells on the MCPB was significantly higher than on the CPB at 7 and 14 days. The MG63 cells with normal phenotype spread well on the MCPB surfaces, and were attached in close proximity to the substrate, as seen by scanning electron microscopy (SEM). The results demonstrated that the MCPB had a good ability to support cell attachment, proliferation and differentiation, and exhibited good cytocompatibility. PMID:20181560

  8. Process for converting magnesium fluoride to calcium fluoride

    DOEpatents

    Kreuzmann, A.B.; Palmer, D.A.

    1984-12-21

    This invention is a process for the conversion of magnesium fluoride to calcium fluoride whereby magnesium fluoride is decomposed by heating in the presence of calcium carbonate, calcium oxide or calcium hydroxide. Magnesium fluoride is a by-product of the reduction of uranium tetrafluoride to form uranium metal and has no known commercial use, thus its production creates a significant storage problem. The advantage of this invention is that the quality of calcium fluoride produced is sufficient to be used in the industrial manufacture of anhydrous hydrogen fluoride, steel mill flux or ceramic applications.

  9. Role of magnesium on the biomimetic deposition of calcium phosphate

    NASA Astrophysics Data System (ADS)

    Sarma, Bimal K.; Sarma, Bikash

    2016-10-01

    Biomimetic depositions of calcium phosphate (CaP) are carried out using simulated body fluid (SBF), calcifying solution and newly developed magnesium containing calcifying solution. Calcium phosphate has a rich phase diagram and is well known for its excellent biocompatibility and bioactivity. The most common phase is hydroxyapatite (HAp), an integral component of human bone and tooth, widely used in orthopedic and dental applications. In addition, calcium phosphate nanoparticles show promise for the targeted drug delivery. The doping of calcium phosphate by magnesium, zinc, strontium etc. can change the protein uptake by CaP nanocrystals. This work describes the role of magnesium on the nucleation and growth of CaP on Ti and its oxide substrates. X-ray diffraction studies confirm formation of HAp nanocrystals which closely resemble the structure of bone apatite when grown using SBF and calcifying solution. It has been observed that magnesium plays crucial role in the nucleation and growth of calcium phosphate. A low magnesium level enhances the crystallinity of HAp while higher magnesium content leads to the formation of amorphous calcium phosphate (ACP) phase. Interestingly, the deposition of ACP phase is rapid when magnesium ion concentration in the solution is 40% of calcium plus magnesium ions concentration. Moreover, high magnesium content alters the morphology of CaP films.

  10. The effect of calcium gluconate and other calcium supplements as a dietary calcium source on magnesium absorption in rats.

    PubMed

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

    1997-01-01

    The effects of commercially available calcium supplements (calcium carbonate, calcium gluconate, oyster shell preparation and bovine bone preparation) and gluconic acid on the absorption of calcium and magnesium were evaluated for 30 days in male Wistar rats. There were no differences in the apparent absorption ratio of calcium among rats fed each calcium supplement; however, the rats fed the calcium gluconate diet had a higher apparent absorption ratio of magnesium than the rats fed the other calcium supplements. Dietary gluconic acid also more markedly stimulated magnesium absorption than the calcium carbonate diet, and the bone (femur and tibia) magnesium contents of rats fed the gluconic acid diet were significantly higher than those of the rats fed the calcium carbonate diet. Furthermore, the weight of cecal tissue and the concentrations of acetic acid and butyric acid in cecal digesta of rats fed the calcium gluconate diet or the gluconic acid diet were significantly increased. We speculate that the stimulation of magnesium absorption in rats fed the calcium gluconate diet is a result of the gluconic acid component and the effect of gluconic acid on magnesium absorption probably results from cecal hypertrophy, magnesium solubility in the large intestine and the effects of volatile fatty acids on magnesium absorption.

  11. Injectable bioactive calcium-magnesium phosphate cement for bone regeneration.

    PubMed

    Wu, Fan; Su, Jiacan; Wei, Jie; Guo, Han; Liu, Changsheng

    2008-12-01

    Novel injectable and degradable calcium-magnesium phosphate cement (CMPC) with rapid-setting characteristic was developed by the introduction of magnesium phosphate cement (MPC) into calcium phosphate cement (CPC). The calcium-magnesium phosphate cement prepared under the optimum P/L ratio exhibited good injectability and desired workability. It could set within 10 min at 37 degrees C in 100% relative humidity and the compressive strength could reach 47 MPa after setting for 48 h, indicating that the prepared cement has relatively high initial mechanical strength. The results of in vitro degradation experiments demonstrated the good degradability of the injectable CMPC, and its degradation rate occurred significantly faster than that of pure CPC in simulated body fluid (SBF) solution. It can be concluded that the novel injectable calcium-magnesium phosphate cement is highly promising for a wide variety of clinical applications, especially for the development of minimally invasive techniques.

  12. Processes affecting the oceanic distributions of dissolved calcium and alkalinity

    SciTech Connect

    Shiller, A.M.; Gieskes, J.M.

    1980-05-20

    Recent studies of the CO/sub 2/ system have suggested that chemical processes in addition to the dissolution and precipitation of calcium carbonate affect the oceanic calcium and alkalinity distributions. Calcium and alkalinity data from the North Pacific have been examined both by using the simple physical-chemical model of previous workers and by a study involving the broader oceanographic context of these data. The simple model is shown to be an inadequate basis for these studies. Although a proton flux associated with organic decomposition may affect the alkalinity, previously reported deviations of calcium-alkalinity correlations from expected trends appear to be related to boundary processes that have been neglected rather than to this proton flux. The distribution of calcium in the surface waters of the Pacific Ocean is examined.

  13. Automatic photometric titrations of calcium and magnesium in carbonate rocks

    USGS Publications Warehouse

    Shapiro, L.; Brannock, W.W.

    1955-01-01

    Rapid nonsubjective methods have been developed for the determination of calcium and magnesium in carbonate rocks. From a single solution of the sample, calcium is titrated directly, and magnesium is titrated after a rapid removal of R2O3 and precipitation of calcium as the tungstate. A concentrated and a dilute solution of disodium ethylenediamine tetraacetate are used as titrants. The concentrated solution is added almost to the end point, then the weak solution is added in an automatic titrator to determine the end point precisely.

  14. Synthesis and Structural Studies of Calcium and Magnesium Phosphinate and Phosphonate Compounds

    NASA Astrophysics Data System (ADS)

    Bampoh, Victoria Naa Kwale

    The work presented herein describes synthetic methodologies leading to the design of a wide array of magnesium and calcium based phosphinate and phosphonates with possible applications as bone scaffolding materials or additives to bone cements. The challenge to the chemistry of the alkaline earth phosphonate target compounds includes poor solubility of compounds, and poorly understood details on the control of the metal's coordination environment. Hence, less is known on phosphonate based alkaline earth metal organic frameworks as compared to transition metal phosphonates. Factors governing the challenges in obtaining crystalline, well-defined magnesium and calcium solids lie in the large metal diameters, the absence of energetically available d-orbitals to direct metal geometry, as well as the overall weakness of the metal-ligand bonds. A significant part of this project was concerned with the development of suitable reaction conditions to obtain X-ray quality crystals of the reaction products to allow for structural elucidation of the novel compounds. Various methodologies to aid in crystal growth including hydrothermal methods and gel crystallization were employed. We have used phosphinate and phosphonate ligands with different number of phosphorus oxygen atoms as well as diphosphonates with different linker lengths to determine their effects on the overall structural features. An interesting correlation is observed between the dimensionality of products and the increasing number of donor oxygen atoms in the ligands as we progress from phosphinic acid to the phosphorous acids. As an example, monophosphinate ligand only yielded one-dimensional compounds, whereas the phosphonates crystallize as one and two-dimensional compounds, and the di- and triphosphonate based compounds display two or three-dimensional geometries. This thesis provides a selection of calcium and magnesium compounds with one-dimensional geometry, as represented in a calcium phosphinate to novel

  15. Multi proxy approach for the formation of calcium carbonates in alkaline man-made environments

    NASA Astrophysics Data System (ADS)

    Rinder, T.; Dietzel, M.; Leis, A.

    2009-04-01

    The formation of calcium carbonates, e.g. in drainage systems of tunnels, may be induced by degassing of CO2-rich groundwater which enters the building. However, the dissolution of portlandite (Ca(OH)2) from cements or the shotcrete of the tunnel wall bears an additional and immense potential for the formation of carbonates from alkaline solutions. Variations in trace element incorporation and distribution of the stable isotopes of carbon and oxygen in the precipitated calcium carbonates may represent powerful tools to identify individual mechanisms for carbonate formation. As portlandite dissolves, highly alkaline solutions are obtained. In this case, precipitation of calcium carbonate can be related to the absorption of CO2 from the atmosphere. Isotopic analyses of the calcite show that fixation of CO2 from the Earth's atmosphere leads to significantly lighter ^13Ccalcite values (down to -25 o/oo, VPDB) as expected for the fixation of groundwater carbonate (typical ^13Ccalcite values between -10 and -16o/oo, VPDB). The evolution of Sr/Ca ratios in the alkaline drainage solutions and in the corresponding calcium carbonate precipitation provides insight into the dissolution process at the concrete with respect to the amount of primarily dissolved portlandite from the cement. Moreover, an inverse relationship between Mg/Ca and Sr/Ca ratios is observed due to the liberation of aqueous strontium by the dissolution of portlandite and the formation of brucite (Mg(OH)2) at alkaline conditions. Less incorporation of magnesium in the calcite structure is a strong indicator for carbonate precipitation from highly alkaline environments. Applications of such multi proxy approaches are discussed with case studies. Main tasks are the reconstruction of the environmental conditions during primary CaCO3 formation and monitoring of ongoing precipitation of calcium carbonates and cement-water interaction in alkaline man-made environments.

  16. Effects of calcium and magnesium on strontium distribution coefficients

    USGS Publications Warehouse

    Bunde, R.L.; Rosentreter, J.J.; Liszewski, M.J.; Hemming, C.H.; Welhan, J.

    1997-01-01

    The effects of calcium and magnesium on the distribution of strontium between a surficial sediment and simulated wastewater solutions were measured as part of an investigation to determine strontium transport properties of surficial sediment at the Idaho National Engineering Laboratory (INEL), Idaho. The investigation was conducted by the U.S. Geological Survey and Idaho State University, in cooperation with the U.S. Department of Energy. Batch experimental techniques were used to determine strontium linear sorption isotherms and distribution coefficients (K(d)'s) using simulated wastewater solutions prepared at pH 8.0??0.1 with variable concentrations of calcium and magnesium. Strontium linear sorption isotherm K(d)'s ranged from 12??1 to 85??3 ml/g, increasing as the concentration of calcium and magnesium decreased. The concentration of sorbed strontium and the percentage of strontium retained by the sediment were correlated to aqueous concentrations of strontium, calcium, and magnesium. The effect of these cation concentrations on strontium sorption was quantified using multivariate least-squares regression techniques. Analysis of data from these experiments indicates that increased concentrations of calcium and magnesium in wastewater discharged to waste disposal ponds at the INEL increases the availability of strontium for transport beneath the ponds by decreasing strontium sorption to the surficial sediment.

  17. Abnormalities of serum calcium and magnesium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Neonatal hypocalcemia is defined as a total serum calcium concentration of <7 mg/dL or an ionized calcium concentration of <4 mg/dL (1mmol/L). In very low birth weight (VLBW) infants, ionized calcium values of 0.8 to 1 mmol/L are common and not usually associated with clinical symptoms. In larger in...

  18. Phase composition, mechanical performance and in vitro biocompatibility of hydraulic setting calcium magnesium phosphate cement.

    PubMed

    Klammert, Uwe; Reuther, Tobias; Blank, Melanie; Reske, Isabelle; Barralet, Jake E; Grover, Liam M; Kübler, Alexander C; Gbureck, Uwe

    2010-04-01

    Brushite (CaHPO(4) x 2H(2)O)-forming calcium phosphate cements are of great interest as bone replacement materials because they are resorbable in physiological conditions. However, their short setting times and low mechanical strengths limit broad clinical application. In this study, we showed that a significant improvement of these properties of brushite cement could be achieved by the use of magnesium-substituted beta-tricalcium phosphate with the general formula Mg(x)Ca((3-x))((PO(4))(2) with 0 < x < 3 as cement reactants. The incorporation of magnesium ions increased the setting times of cements from 2 min for a magnesium-free matrix to 8-11 min for Mg(2.25)Ca(0.75)(PO(4))(2) as reactant. At the same time, the compressive strength of set cements was doubled from 19 MPa to more than 40 MPa after 24h wet storage. Magnesium ions were not only retarding the setting reaction to brushite but were also forming newberyite (MgHPO(4) x 3H(2)O) as a second setting product. The biocompatibility of the material was investigated in vitro using the osteoblast-like cell line MC3T3-E1. A considerable increase of cell proliferation and expression of alkaline phosphatase, indicating an osteoblastic differentiation, could be noticed. Scanning electron microscopy analysis revealed an obvious cell growth on the surface of the scaffolds. Analysis of the culture medium showed minor alterations of pH value within the physiological range. The concentrations of free calcium, magnesium and phosphate ions were altered markedly due to the chemical solubility of the scaffolds. We conclude that the calcium magnesium phosphate (newberyite) cements have a promising potential for their use as bone replacement material since they provide a suitable biocompatibility, an extended workability and improved mechanical performance compared with brushite cements.

  19. Effects of dietary vitamin D on calcium and magnesium levels in mice with abnormal calcium metabolism

    SciTech Connect

    Spurlock, B.G.; West, W.L.; Knight, E.M. )

    1991-03-11

    In previous studies vitamin D has been used to induce cardiac calcium overload in laboratory animals. Interrelationships between calcium and magnesium metabolism are also documented. The authors have investigated the effect of varying vitamin D in the diet on calcium and magnesium levels in plasma, kidney and heart of DBA mice which exhibit genetic abnormalities in cardiac calcium metabolism. Weanling DBA mice were maintained for 28 days on an AIN-76 diet containing either 1,000 I.U. of vitamin D{sub 3} per kg of diet (control); 4,000 I.U. of vitamin D{sub 3} per kg of diet; or no vitamin D. When compared to controls, supplemented animals showed significantly higher plasma magnesium, kidney calcium and kidney magnesium levels; animals receiving the vitamin D-deficient diet exhibited increases in cardiac calcium levels. The authors results support previous findings that vitamin D deficiency increases cardiac calcium uptake and suggest a possible role of vitamin D in magnesium metabolism.

  20. Disorders of calcium, phosphorus, and magnesium metabolism in the neonate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Approximately 98% of the calcium, 80% of the phosphorus, and 65% of the magnesium in the body are in the skeleton. These elements, often referred to as the "bone minerals" are also constituents of the intracellular and extracellular spaces. The metabolism of these bone minerals and mineralization of...

  1. Quantitative changes of calcium, phosphorus, and magnesium in common iliac arteries with aging.

    PubMed

    Tohno, S; Tohno, Y; Moriwake, Y; Azuma, C; Ohnishi, Y; Minami, T

    2001-01-01

    To elucidate the mechanism of element accumulations in the arteries with aging, the authors investigated the mass ratios among calcium, phosphorus, and magnesium in the common iliac arteries by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of 16 men and 8 women, ranging in age from 65 to 93 yr. It was found that there were extremely significant correlations between calcium and phosphorus contents, between calcium and magnesium contents, and between phosphorus and magnesium contents in the common iliac arteries. In regard to the mass ratio, although the mass ratio of calcium to phosphorus was almost constant, the mass ratios of magnesium to calcium and phosphorus were different at early and advanced stages of the accumulation of calcium and phosphorus. It was found that both the mass ratios of magnesium to calcium and phosphorus were higher at an early stage of the accumulation of calcium and phosphorus in the arteries than at an advanced stage of the accumulation.

  2. Magnesium substitution in the structure of orthopedic nanoparticles: A comparison between amorphous magnesium phosphates, calcium magnesium phosphates, and hydroxyapatites.

    PubMed

    Nabiyouni, Maryam; Ren, Yufu; Bhaduri, Sarit B

    2015-01-01

    As biocompatible materials, magnesium phosphates have received a lot of attention for orthopedic applications. During the last decade multiple studies have shown advantages for magnesium phosphate such as lack of cytotoxicity, biocompatibility, strong mechanical properties, and high biodegradability. The present study investigates the role of Mg(+2) and Ca(+2) ions in the structure of magnesium phosphate and calcium phosphate nanoparticles. To directly compare the effect of Mg(+2) and Ca(+2) ions on structure of nanoparticles and their biological behavior, three groups of nanoparticles including amorphous magnesium phosphates (AMPs) which release Mg(+2), calcium magnesium phosphates (CMPs) which release Mg(+2) and Ca(+2), and hydroxyapatites (HAs) which release Ca(+2) were studied. SEM, TEM, XRD, and FTIR were used to evaluate the morphology, crystallinity, and chemical properties of the particles. AMP particles were homogeneous nanospheres, whereas CMPs were combinations of heterogeneous nanorods and nanospheres, and HAs which contained heterogeneous nanosphere particles. Cell compatibility was monitored in all groups to determine the cytotoxicity effect of particles on studied MC3T3-E1 preosteoblasts. AMPs showed significantly higher attachment rate than the HAs after 1 day and both AMPs and CMPs showed significantly higher proliferation rate when compared to HAs after 7days. Gene expression level of osteoblastic markers ALP, COL I, OCN, OPN, RUNX2 were monitored and they were normalized to GAPDH housekeeping gene. Beta actin expression level was monitored as the second housekeeping gene to confirm the accuracy of results. In general, AMPs and CMPs showed higher expression level of osteoblastic genes after 7 days which can further confirm the stimulating role of Mg(+2) and Ca(+2) ions in increasing the proliferation rate, differentiation, and mineralization of MC3T3-E1 preosteoblasts.

  3. Magnesium balance in adolescent females consuming a low- or high-calcium diet.

    PubMed

    Andon, M B; Ilich, J Z; Tzagournis, M A; Matkovic, V

    1996-06-01

    Increasing emphasis is being placed on optimizing calcium intake during growth as a way to enhance peak bone mass. Although some studies in adults have shown that high calcium intake may negatively affect magnesium utilization, few data are available regarding the interaction of calcium and magnesium in healthy children. The purpose of our study was to measure the effect of calcium intake on magnesium balance in 26 adolescent girls (mean age 11.3 y) during a 14-d period. Subjects ate a controlled basal diet containing 667 mg Ca and 176 mg Mg. In addition to the basal diet, subjects were randomly assigned in a double-blind fashion to consume 1000 mg elemental Ca/d as calcium citrate malate or a placebo. Magnesium use did not differ between the low-calcium and high-calcium groups as measured by absorption (50% compared with 55%), urinary excretion (70 compared with 74 mg/d), and fecal excretion (88 compared with 79 mg/d). Accordingly, magnesium balance was not different in subjects consuming 667 or 1667 mg Ca/d and averaged 21 mg Mg/d for the whole study group. Magnesium balance was significantly correlated with magnesium intake (r = 0.511, P = 0.008) and magnesium absorption (r = 0.723, P < 0.001). Prediction intervals from the regression of magnesium balance on intake indicated that the current recommended dietary allowance of magnesium would result in magnesium balance > or = 8.5 mg/d in 95% of the girls. This value appears consistent with long-term accretion rates needed to account for the expansion of the total-body magnesium pool during growth. In summary, our observations support the adequacy of the current recommended dietary allowance for magnesium and indicate that alterations in magnesium utilization should not be anticipated in adolescent females consuming a high-calcium diet.

  4. Stability and broad-sense heritability of mineral content in potato: calcium and magnesium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calcium and magnesium are two minerals with prominent roles in animal and plant metabolism. Advanced potato breeding lines were found to contain between 266 and 944 µg per gram fresh weight of calcium and between 705 1089 µg per gram fresh weight of magnesium. All trials had significant genotype b...

  5. A field method for the determination of calcium and magnesium in limestone and dolomite

    USGS Publications Warehouse

    Shapiro, Leonard; Brannock, Walter Wallace

    1957-01-01

    The method is an adaptation of a procedure described by Betz and Noll1 in 1950. Calcium and magnesium are determined by visual titration using Versene (disodium ethylenediamine tetraacetate) with Murexide (ammonium purpurate) as the indicator for calcium and Eriochrome Black T as the indicator for magnesium.

  6. Magnesium supplementation through seaweed calcium extract rather than synthetic magnesium oxide improves femur bone mineral density and strength in ovariectomized rats.

    PubMed

    Bae, Yun Jung; Bu, So Young; Kim, Jae Young; Yeon, Jee-Young; Sohn, Eun-Wha; Jang, Ki-Hyo; Lee, Jae-Cheol; Kim, Mi-Hyun

    2011-12-01

    Commercially available seaweed calcium extract can supply high amounts of calcium as well as significant amounts of magnesium and other microminerals. The purpose of this study was to investigate the degree to which the high levels of magnesium in seaweed calcium extract affects the calcium balance and the bone status in ovariectomized rats in comparison to rats supplemented with calcium carbonate and magnesium oxide. A total of 40 Sprague-Dawley female rats (7 weeks) were divided into four groups and bred for 12 weeks: sham-operated group (Sham), ovariectomized group (OVX), ovariectomized with inorganic calcium and magnesium supplementation group (OVX-Mg), and ovariectomized with seaweed calcium and magnesium supplementation group (OVX-SCa). All experimental diets contained 0.5% calcium. The magnesium content in the experimental diet was 0.05% of the diet in the Sham and OVX groups and 0.1% of the diet in the OVX-Mg and OVX-SCa groups. In the calcium balance study, the OVX-Mg and OVX-SCa groups were not significantly different in calcium absorption compared to the OVX group. However, the femoral bone mineral density and strength of the OVX-SCa group were higher than those of the OVX-Mg and OVX groups. Seaweed calcium with magnesium supplementation or magnesium supplementation alone did not affect the serum ALP and CTx levels in ovariectomized rats. In summary, consumption of seaweed calcium extract or inorganic calcium carbonate with magnesium oxide demonstrated the same degree of intestinal calcium absorption, but only the consumption of seaweed calcium extract resulted in increased femoral bone mineral density and strength in ovariectomized rats. Our results suggest that seaweed calcium extract is an effective calcium and magnesium source for improving bone health compared to synthetic calcium and magnesium supplementation.

  7. Beta-type calcium phosphates with and without magnesium: From hydrolysis of brushite powder to robocasting of periodic scaffolds.

    PubMed

    Richard, Raquel C; Sader, Márcia S; Dai, Jisen; Thiré, Rossana M S M; Soares, Gloria D A

    2014-10-01

    Several approaches have attempted to replace extensive bone loss, but each of them has their limitation. Nowadays, additive manufacture techniques have shown great potential for bone engineering. The objective of this study was to synthesize beta tricalcium phosphate (β-TCP), beta tricalcium phosphate substituted by magnesium (β-TCMP), and biphasic calcium phosphate substituted by magnesium (BCMP) via hydrolysis and produce scaffolds for bone regeneration using robocasting technology. Calcium deficient apatites, with and without magnesium were obtained by hydrolysis, calcined and physico-chemically characterized. Colorimetric cell viability assay, calcium nodule formation, and the expression of alkaline phosphatase, osteocalcin, transforming growth factor beta-1 and collagen were assessed using a mouse osteoblastic cell line (MC3T3-E1). Direct-write assembly of cylindrical periodic scaffolds was done via robotic deposition using β-TCP, β-TCMP, and BCMP colloidal inks. The sintered scaffolds were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, Archimede's method, and uniaxial compression test. According to the cell viability assay, the powders induced cell proliferation. Calcium nodule formation and bone markers activity suggested that the materials present potential value in bone tissue engineering. The scaffolds built by robocasting presented interconnected porous and exhibited mean compressive strength between 7.63 and 18.67 MPa, compatible with trabecular bone.

  8. Calcium orthophosphate coatings on magnesium and its biodegradable alloys.

    PubMed

    Dorozhkin, Sergey V

    2014-07-01

    Biodegradable metals have been suggested as revolutionary biomaterials for bone-grafting therapies. Of these metals, magnesium (Mg) and its biodegradable alloys appear to be particularly attractive candidates due to their non-toxicity and as their mechanical properties match those of bones better than other metals do. Being light, biocompatible and biodegradable, Mg-based metallic implants have several advantages over other implantable metals currently in use, such as eliminating both the effects of stress shielding and the requirement of a second surgery for implant removal. Unfortunately, the fast degradation rates of Mg and its biodegradable alloys in the aggressive physiological environment impose limitations on their clinical applications. This necessitates development of implants with controlled degradation rates to match the kinetics of bone healing. Application of protective but biocompatible and biodegradable coatings able to delay the onset of Mg corrosion appears to be a reasonable solution. Since calcium orthophosphates are well tolerated by living organisms, they appear to be the excellent candidates for such coatings. Nevertheless, both the high chemical reactivity and the low melting point of Mg require specific parameters for successful deposition of calcium orthophosphate coatings. This review provides an overview of current coating techniques used for deposition of calcium orthophosphates on Mg and its biodegradable alloys. The literature analysis revealed that in all cases the calcium orthophosphate protective coatings both increased the corrosion resistance of Mg-based metallic biomaterials and improved their surface biocompatibility.

  9. Dissolved Calcium and Magnesium Carbonates Promote Arsenate Release From Ferrihydrite in Flow Systems

    NASA Astrophysics Data System (ADS)

    Saalfield, S. L.; Bostick, B. C.

    2007-12-01

    Field data from water systems around the world have shown that arsenic can reach toxic concentrations in dynamic groundwater systems. This is generally in contrast to analogous static systems at circumneutral pH, where arsenic is strongly retained by sorption to iron (hydr)oxides. Our research examines the effect of calcium and magnesium carbonates on As(V) mobility. In both dynamic flow and static experiments, arsenate was pre- sorbed to poorly crystalline iron hydroxides (1-10% sorption capacity), with varying aqueous compositions including calcium, magnesium, carbonate, sulfate, lactate, and other common groundwater species (pH 7.5-8). Thus we investigated how the dissolution of common carbonate minerals, specifically CaCO3 and MgCO3, affect arsenic behavior in the context of groundwater solutions. Under static (batch) conditions, no measurable arsenic (<10 μg/L) is released into solutions containing alkaline earth metals (AEMs) and carbonates. When elevated concentrations of AEMs and carbonate are introduced by dynamic flow, however, arsenic is mobilized at up to 500 μg/L, releasing significant proportions the total arsenic present. This is only the case when both of these species are present; with other common ion pairs, little to no arsenic is released. These results indicate that arsenate adsorption is kinetically controlled under flow conditions, resulting in very different mobility relative to otherwise equivalent static systems. Furthermore, the combination of alkaline earth metals and carbonates promotes As(V) mobility in column-based systems. We propose that these phenomena indicate a combination of physical and chemical effects by which diffusion limitation becomes dominant in limiting arsenic sorption in flow systems. Many carbonate-buffered aquifers, as well as those undergoing rapid mineralization of organic matter, could be affected by these processes of AEM-carbonate-limited sorption and increased arsenic mobility.

  10. Recent advances in research on magnesium alloys and magnesium-calcium phosphate composites as biodegradable implant materials.

    PubMed

    Kuśnierczyk, Katarzyna; Basista, Michał

    2016-07-01

    Magnesium alloys are modern biocompatible materials suitable for orthopaedic implants due to their biodegradability in biological environment. Many studies indicate that there is a high demand to design magnesium alloys with controllable in vivo corrosion rates and required mechanical properties. A solution to this challenge can be sought in the development of metal matrix composites based on magnesium alloys with addition of relevant alloying elements and bioceramic particles. In this study, the corrosion mechanisms along with corrosion protection methods in magnesium alloys are discussed. The recently developed magnesium alloys for biomedical applications are reviewed. Special attention is given to the newest research results in metal matrix composites composed of magnesium alloy matrix and calcium phosphates, especially hydroxyapatite or tricalcium phosphate, as the second phase with emphasis on the biodegradation behavior, microstructure and mechanical properties in view of potential application of these materials in bone implants.

  11. Calcium and magnesium concentrations in mature human milk: influence of calcium intake, age and socioeconomic level.

    PubMed

    Vítolo, M R; Valente Soares, L M; Carvalho, E B; Cardoso, C B

    2004-03-01

    Concentrations of calcium and magnesium were measured in mature milk, collected between 30 and 90 days after childbirth, from a group of 90 mothers between 14 and 39 years of age, exclusively breastfeeding. The group was divided into three sub-groups: low socioeconomic-level adolescents (LSAd), low socioeconomic-level adults (LSA), and high socioeconomic-level adults (HSA). Each mother's nutritional status was determined using the body-mass index (BMI) and her eating habits, obtained on the basis of a 24-h dietary recall. Adolescent and adult mothers in the low socioeconomic-level group had lower average calcium intake (LSAd = 618.4 +/- 555.2 mg and LSA = 679.4 +/- 411.4 mg) than adult mothers in the higher socioeconomic-level group (853.6 +/- 415.5 mg). The average concentration of calcium in the adolescent mothers' milk (LSAd) was significantly lower (5.30 +/- 1.42 mmol Ca/L, P = 0.01) than that of the two adult groups (LSA = 5.82 +/- 1.55 mmol Ca/L and HSA = 6.40 mmol Ca/L). The average magnesium concentrations for all groups did not show significant differences (LSAd = 1.06 +/- 0.18, LSA = 1.16 +/- 0.23 and HSA = 1.11 +/- 0.23 mmol Mg/L, for P= 0.16). These results indicate that magnesium concentrations in mature human milk do not seem to depend on maternal nutritional status. The condition of adolescence, however, associated with lower calcium intake by the mother, resulted in lower calcium concentrations in the milk secreted when compared to that of adult mothers.

  12. Crystallization Kinetics of Calcium-magnesium Aluminosilicate (CMAS) Glass

    NASA Technical Reports Server (NTRS)

    Wiesner, Valerie L.; Bansal, Narottam P.

    2015-01-01

    The crystallization kinetics of a calcium-magnesium aluminosilicate (CMAS) glass with composition relevant for aerospace applications, like air-breathing engines, were evaluated using differential thermal analysis (DTA) in powder and bulk forms. Activation energy and frequency factor values for crystallization of the glass were evaluated. X-ray diffraction (XRD) was used to investigate the onset of crystallization and the phases that developed after heat treating bulk glass at temperatures ranging from 690 to 960 deg for various times. Samples annealed at temperatures below 900 deg remained amorphous, while specimens heat treated at and above 900 deg exhibited crystallinity originating at the surface. The crystalline phases were identified as wollastonite (CaSiO3) and aluminum diopside (Ca(Mg,Al) (Si,Al)2O6). Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were employed to examine the microstructure and chemical compositions of crystalline phases formed after heat treatment.

  13. Moderate alcohol consumption and urinary excretion of magnesium and calcium.

    PubMed

    Rylander, R; Mégevand, Y; Lasserre, B; Amstutz, W; Granbom, S

    2001-01-01

    The aim of this study was to evaluate the magnesium (Mg) status of male subjects consuming moderate amounts of alcohol (n = 14) in comparison with that of a group of non-consumers of alcohol (n = 10). Plasma ionized Mg levels and total erythrocyte Mg content were determined as well as the excretion of Mg in urine before and after an oral loading test. Intake of Mg via food and water was estimated using a one-week dietary records. The results showed a significantly higher, alcohol dose-related excretion of Mg and Ca (calcium) in the urine after the oral Mg load among consumers of alcohol. Although the study is based on a small number of subjects with differences in smoking habits, it is suggested that alcohol consumption even in moderate amounts could contribute to Mg deficiency.

  14. Anhydrobiosis in yeast: influence of calcium and magnesium ions on yeast resistance to dehydration-rehydration.

    PubMed

    Trofimova, Yuliya; Walker, Graeme; Rapoport, Alexander

    2010-07-01

    The influence of calcium and magnesium ions on resistance to dehydration in the yeast, Saccharomyces cerevisiae, was investigated. Magnesium ion availability directly influenced yeast cells' resistance to dehydration and, when additionally supplemented with calcium ions, this provided further significant increase of yeast resistance to dehydration. Gradual rehydration of dry yeast cells in water vapour indicated that both magnesium and calcium may be important for the stabilization of yeast cell membranes. In particular, calcium ions were shown for the first time to increase the resistance of yeast cells to dehydration in stress-sensitive cultures from exponential growth phases. It is concluded that magnesium and calcium ion supplementations in nutrient media may increase the dehydration stress tolerance of S. cerevisiae cells significantly, and this finding is important for the production of active dry yeast preparations for food and fermentation industries.

  15. Calcium and calcium magnesium carbonate specimens submitted as urinary tract stones.

    PubMed

    Gault, M H; Chafe, L; Longerich, L; Mason, R A

    1993-02-01

    Of 8,129 specimens submitted as urinary stones from 6,095 patients, 67 from 15 patients were predominantly calcium carbonate or calcium magnesium carbonate (dolomite) by infrared analysis. Detailed study of 1 man and 4 women who submitted 3 or more such specimens showed that all were of aragonite calcium carbonate crystal form in 2 women and all calcite in the man. All 3 patients had a long history of nephrolithiasis preceding submission of calcium carbonate stones. There was frequent and often painful spontaneous passage of many small stones. Medullary sponge kidney was reported in 2 patients. Specimens submitted by the other 2 women included dolomite and quartz artifacts. Of the other 10 patients 4 had calcite and 1 had aragonite (possibly true stones). Five patients had artifacts with dolomite in 3 and mixed specimens in 2. True calcium carbonate kidney stones and calcium carbonate artifacts may be difficult to distinguish, and dolomite and quartz artifacts may require x-ray diffraction for clear-cut diagnosis.

  16. Polychlorinated biphenyls-containing electrical insulating oil contaminated soil treatment with calcium and magnesium peroxides.

    PubMed

    Goi, Anna; Viisimaa, Marika; Trapido, Marina; Munter, Rein

    2011-02-01

    Calcium and magnesium peroxides were applied for the treatment of soil contaminated by polychlorinated biphenyls-containing electrical insulating oil (Aroclor 1016). The removal of PCB-containing electrical insulating oil was achieved with the addition of either calcium peroxide or magnesium peroxide alone and dependent on dosages of the chemical. A 21-d treatment of 60% watered soil with the moderate addition (chemical/oil weight ratio of 0.005/1) of either calcium peroxide or magnesium peroxide resulted in nearly complete (96 ± 2%) oil removal, unsubstantial increase in soil pH and almost no changes in oxygen consumption and dehydrogenase activity, making it suitable for the soil decontamination.

  17. Hierarchically microporous/macroporous scaffold of magnesium-calcium phosphate for bone tissue regeneration.

    PubMed

    Wei, Jie; Jia, Junfeng; Wu, Fan; Wei, Shicheng; Zhou, Huanjun; Zhang, Hongbo; Shin, Jung-Woog; Liu, Changsheng

    2010-02-01

    Hierarchically 3D microporous/macroporous magnesium-calcium phosphate (micro/ma-MCP) scaffolds containing magnesium ammonium phosphate hexahydrate [NH(4)MgPO(4).6H(2)O] and hydroxyapatite [Ca(10)(PO(4))(6)(OH)(2)] were fabricated from cement utilizing leaching method in the presence of sodium chloride (NaCl) particles and NaCl saturated water solution. NaCl particles produced macroporosity, and NaCl solution acted as both cement liquid and porogens, inducing the formation of microporosity. The micro/ma-MCP scaffolds with porosities varied from 52 to 78% showed well interconnected and open macropores with the sizes of 400-500 microm, and degradation of the scaffolds was significantly enhanced in Tris-HCl solution compared with macroporous MCP (ma-MCP) and corresponding calcium phosphate cement (CPC) scaffolds. Cell attachment and proliferation of MG(63) on micro/ma-MCP were significantly better than ma-MCP and CPC scaffolds because of the presence of microporosity, which enhanced the surface area of the scaffolds. Moreover, the alkaline phosphatase (ALP) activity of the MG(63) cells on micro/ma-MCP was significantly higher than ma-MCP and CPC scaffolds at 7 days, and the MG(63) cells with normal phenotype spread well and formed confluent layers across the macroporous walls of the micro/ma-MCP scaffolds. Histological evaluation confirmed that the micro/ma-MCP scaffolds improved the efficiency of new bone regeneration, and exhibited excellent biocompatibility, biodegradability and faster and more effective osteogenesis in vivo.

  18. Essential Nutrient Interactions: Does Low or Suboptimal Magnesium Status Interact with Vitamin D and/or Calcium Status?12

    PubMed Central

    Rosanoff, Andrea; Dai, Qi; Shapses, Sue A

    2016-01-01

    Although much is known about magnesium, its interactions with calcium and vitamin D are less well studied. Magnesium intake is low in populations who consume modern processed-food diets. Low magnesium intake is associated with chronic diseases of global concern [e.g., cardiovascular disease (CVD), type 2 diabetes, metabolic syndrome, and skeletal disorders], as is low vitamin D status. No simple, reliable biomarker for whole-body magnesium status is currently available, which makes clinical assessment and interpretation of human magnesium research difficult. Between 1977 and 2012, US calcium intakes increased at a rate 2–2.5 times that of magnesium intakes, resulting in a dietary calcium to magnesium intake ratio of >3.0. Calcium to magnesium ratios <1.7 and >2.8 can be detrimental, and optimal ratios may be ∼2.0. Background calcium to magnesium ratios can affect studies of either mineral alone. For example, US studies (background Ca:Mg >3.0) showed benefits of high dietary or supplemental magnesium for CVD, whereas similar Chinese studies (background Ca:Mg <1.7) showed increased risks of CVD. Oral vitamin D is widely recommended in US age-sex groups with low dietary magnesium. Magnesium is a cofactor for vitamin D biosynthesis, transport, and activation; and vitamin D and magnesium studies both showed associations with several of the same chronic diseases. Research on possible magnesium and vitamin D interactions in these human diseases is currently rare. Increasing calcium to magnesium intake ratios, coupled with calcium and vitamin D supplementation coincident with suboptimal magnesium intakes, may have unknown health implications. Interactions of low magnesium status with calcium and vitamin D, especially during supplementation, require further study. PMID:26773013

  19. Essential Nutrient Interactions: Does Low or Suboptimal Magnesium Status Interact with Vitamin D and/or Calcium Status?

    PubMed

    Rosanoff, Andrea; Dai, Qi; Shapses, Sue A

    2016-01-01

    Although much is known about magnesium, its interactions with calcium and vitamin D are less well studied. Magnesium intake is low in populations who consume modern processed-food diets. Low magnesium intake is associated with chronic diseases of global concern [e.g., cardiovascular disease (CVD), type 2 diabetes, metabolic syndrome, and skeletal disorders], as is low vitamin D status. No simple, reliable biomarker for whole-body magnesium status is currently available, which makes clinical assessment and interpretation of human magnesium research difficult. Between 1977 and 2012, US calcium intakes increased at a rate 2-2.5 times that of magnesium intakes, resulting in a dietary calcium to magnesium intake ratio of >3.0. Calcium to magnesium ratios <1.7 and >2.8 can be detrimental, and optimal ratios may be ∼2.0. Background calcium to magnesium ratios can affect studies of either mineral alone. For example, US studies (background Ca:Mg >3.0) showed benefits of high dietary or supplemental magnesium for CVD, whereas similar Chinese studies (background Ca:Mg <1.7) showed increased risks of CVD. Oral vitamin D is widely recommended in US age-sex groups with low dietary magnesium. Magnesium is a cofactor for vitamin D biosynthesis, transport, and activation; and vitamin D and magnesium studies both showed associations with several of the same chronic diseases. Research on possible magnesium and vitamin D interactions in these human diseases is currently rare. Increasing calcium to magnesium intake ratios, coupled with calcium and vitamin D supplementation coincident with suboptimal magnesium intakes, may have unknown health implications. Interactions of low magnesium status with calcium and vitamin D, especially during supplementation, require further study.

  20. [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.

  1. Calcium and magnesium status is not impaired in pregnant women.

    PubMed

    Rocha, Vivianne S; Lavanda, Ivana; Nakano, Eduardo Y; Ruano, Rodrigo; Zugaib, Marcelo; Colli, Célia

    2012-07-01

    Deficiencies in calcium (Ca) and magnesium (Mg) are associated with various complications during pregnancy. To test the hypothesis that the status of these minerals is inadequate in pregnancy, a cross-sectional study was conducted of the dietary intake and status of Ca and Mg in pregnant women (n = 50) attending a general public university hospital in Brazil. Dietary intake was assessed from 4-day food records; levels of plasma Mg, erythrocyte Mg, and urinary Ca and Mg excretion were determined by flame atomic absorption spectroscopy; and type I collagen C-telopeptides were evaluated by enzyme-linked immunosorbent assay. Probabilities of inadequate Ca and Mg intake were exhibited by 58 and 98% of the study population, respectively. The mean levels of urinary Ca and Mg excretion were 8.55 and 3.77 mmol/L, respectively. Plasma C-telopeptides, plasma Mg, and erythrocyte Mg were within normal levels. Multiple linear regression analysis revealed positive relationships among urinary Ca excretion, Ca intake (P = .002) and urinary Mg excretion (P < .001) and between erythrocyte Mg and Mg intake (P = .023). It is concluded that the Ca and Mg status of participants was adequate even though the intake of Ca and Mg was lower than the recommended level.

  2. Magnesium-Calcite Crystal Formation Mediated by the Thermophilic Bacterium Geobacillus thermoglucosidasius Requires Calcium and Endospores.

    PubMed

    Murai, Rie; Yoshida, Naoto

    2016-11-01

    Fresh Geobacillus thermoglucosidasius cells grown on soybean-casein digest nutrient agar were inoculated as a parent colony 1 cm in diameter on the surface of an agar gel containing acetate and calcium ions (calcite-promoting hydrogel) and incubated at 60 °C for 4 days, after which magnesium-calcite single crystals of 50-130 µm in size formed within the parent colony. Addition of EDTA, polyacrylic acid or N,N-dicyclohexylcarbodiimide to the calcite-forming hydrogel inhibited the parent colony from forming magnesium-calcite crystals. Inoculation of G. thermoglucosidasius on calcite-forming hydrogel containing 5 µM cadmium and 20 µM zinc resulted in a decrease in the sporulation rate from 55 to 7-8 %. Magnesium-calcite synthesis decreased relative to the sporulation rate. G. thermoglucosidasius exhibited higher adsorption/absorbance of calcium than other Geobacillus sp. that do not mediate calcite formation and higher levels of magnesium accumulation. Calcium ions contained in the calcite-promoting hydrogel and magnesium ions concentrated in G. thermoglucosidasius cells serve as the elements for magnesium-calcite synthesis. The observed decreases in sporulation rate and magnesium-calcite formation support the hypothesis that endospores act as nuclei for the synthesis of magnesium-calcite single crystals.

  3. Influence of magnesium on the absorption and excretion of calcium and oxalate ions.

    PubMed

    Berg, W; Bothor, C; Pirlich, W; Janitzky, V

    1986-01-01

    In two test series additional oxalic acid excretion in urine was induced in healthy test persons by administering a spinach diet. This additional excretion could be markedly reduced by magnesium administration. Calcium and citrate excretions are largely unaffected by magnesium administration. Magnesium excretions, however, are clearly increased. The calcium oxalate crystallization rates in the 5-or 7-hour urines reveal a behavior parallel to that of the oxalic acid excretion profile. In the control urines, the crystal picture is characterized by numerous medium-sized whewellite crystals. In contrast, in the test series weddellite crystals are reduced in size and frequency after magnesium administration. New aspects of magnesium effects must be discussed; above all the possible absorption changes resulting from gastrointestinal diseases.

  4. Recovery of phosphorus and nitrogen from alkaline hydrolysis supernatant of excess sludge by magnesium ammonium phosphate.

    PubMed

    Bi, Wei; Li, Yiyong; Hu, Yongyou

    2014-08-01

    Magnesium ammonium phosphate (MAP) method was used to recover orthophosphate (PO₄(3-)-P) and ammonium nitrogen (NH4(+)-N) from the alkaline hydrolysis supernatant of excess sludge. To reduce alkali consumption and decrease the pH of the supernatant, two-stage alkaline hydrolysis process (TSAHP) was designed. The results showed that the release efficiencies of PO₄(3-)-P and NH₄(+)-N were 41.96% and 7.78%, respectively, and the pH of the supernatant was below 10.5 under the running conditions with initial pH of 13, volume ratio (sludge dosage/water dosage) of 1.75 in second-stage alkaline hydrolysis reactor, 20 g/L of sludge concentration in first-stage alkaline hydrolysis reactor. The order of parameters influencing MAP reaction was analyzed and the optimized conditions of MAP reaction were predicted through the response surface methodology. The recovery rates of PO₄(3-)-P and NH₄(+)-N were 46.88% and 16.54%, respectively under the optimized conditions of Mg/P of 1.8, pH 9.7 and reaction time of 15 min.

  5. A facile magnesium-containing calcium carbonate biomaterial as potential bone graft.

    PubMed

    He, Fupo; Zhang, Jing; Tian, Xiumei; Wu, Shanghua; Chen, Xiaoming

    2015-12-01

    The calcium carbonate is the main composition of coral which has been widely used as bone graft in clinic. Herein, we readily prepared novel magnesium-containing calcium carbonate biomaterials (MCCs) under the low-temperature conditions based on the dissolution-recrystallization reaction between unstable amorphous calcium carbonate (ACC) and metastable vaterite-type calcium carbonate with water involved. The content of magnesium in MCCs was tailored by adjusting the proportion of ACC starting material that was prepared using magnesium as stabilizer. The phase composition of MCCs with various amounts of magnesium was composed of one, two or three kinds of calcium carbonates (calcite, aragonite, and/or magnesian calcite). The different MCCs differed in topography. The in vitro degradation of MCCs accelerated with increasing amount of introduced magnesium. The MCCs with a certain amount of magnesium not only acquired higher compressive strength, but also promoted in vitro cell proliferation and osteogenic differentiation. Taken together, the facile MCCs shed light on their potential as bone graft.

  6. Effect of root canal filling materials containing calcium hydroxide on the alkalinity of root dentin.

    PubMed

    Staehle, H J; Spiess, V; Heinecke, A; Müller, H P

    1995-08-01

    The effect of root canal filling pastes containing calcium oxide resp. calcium hydroxide on the alkalinity of extracted human teeth was investigated using a colour indicator (cresol red). An aqueous suspension of calcium hydroxide (Pulpdent), which is normally used for temporary root canal filling, most consistently produced alkalinity. Removal of the smear layer following instrumentation of the root canal led to increased proportion of alkaline-positive spots in dentinal locations distant from the canal. A clearly smaller effect was found with a calcium salicylate cement (Sealapex) and an oil-paste (Gangraena Merz), both of which are available for definite root canal fillings. Following removal of the smear layer, these hard-setting preparations caused moderate alkalinity in dentin adjacent to the canal but no effect was observed in locations more distant from the canal. Neither at locations adjacent to nor distant from the root canal was alkalinity found when another calcium salicylate cement (Apexit) was used. Apparently the release of hydroxyl ions into root dentin from calcium hydroxide containing root canal filling materials is not solely influenced by the absolute amount of calcium hydroxide, but also depends on other ingredients which variably inhibit the release of these ions.

  7. Calcium and magnesium levels during automated plateletpheresis in normal donors.

    PubMed

    Das, S S; Chaudhary, R; Khetan, D; Shukla, J S; Agarwal, P; Mishra, R B

    2005-06-01

    It is well known that citrate induces ionized hypocalcaemia by the chelating effect during plateletpheresis. However, the kinetics of serum magnesium (Mg) ions has not been well documented. We, therefore, evaluated biochemical changes in healthy donors during plateletpheresis procedure. Ten healthy donors underwent plateletpheresis on continuous cell separator (CS3000, Baxter, Round Lake, IL, USA) and 10 on intermittent flow cell separator (MCS 3p, Hemonetics, Braintree, MA, USA). Serum levels of total and ionized calcium (tCa and iCa, respectively) and Mg (tMg and iMg, respectively) were measured before, during and after the procedures. Although, the fall in tCa (from 2.62 +/- 0.12 to 2.36 +/- 0.12 mmol L(-1)) and tMg (from 0.89 +/- 0.01 to 0.79 +/- 0.01 mmol L(-1)) was modest and not significant; drop in iCa (from 1.33 +/- 0.1 to 0.84 +/- 0.1 mmol L(-1)) and iMg (from 0.53 +/- 0.01 to 0.35 +/- 0.1 mmol L(-1)) was statistically significant (P < 0.001). There were no significant differences observed between the CS3000 and MCS 3p cell separators regarding the fall in Ca and Mg. None of the donors experienced any adverse reactions during the procedures. In the study, an acute ionized hypocalcaemia and hypomagnesaemia have been observed after the plateletpheresis; therefore, measurement of both the ions may be monitored. However, there is no justification for prophylactic supplementation of either of these elements.

  8. Calcium and magnesium in drinking water and risk of death from acute myocardial infarction in Taiwan.

    PubMed

    Yang, Chun-Yuh; Chang, Chih-Ching; Tsai, Shang-Shyue; Chiu, Hui-Fen

    2006-07-01

    Many studies have examined the association between cardiovascular disease mortality and water hardness. However, the results have not been consistent. This report examines whether calcium and magnesium in drinking water are protective against acute myocardial infarction (AMI). All eligible AMI deaths (10,094 cases) of Taiwan residents from 1994 to 2003 were compared with deaths from other causes (10,094 controls), and the levels of calcium and magnesium in drinking water of these residents were determined. Data on calcium and magnesium levels in drinking water throughout Taiwan have been obtained from the Taiwan Water Supply Corporation. The control group consisted of people who died from other causes and the controls were pair matched to the cases by sex, year of birth, and year of death. The adjusted odd ratios (95% confidence interval) were 0.79 (0.73-0.86) for the group with water calcium levels between 25.1 and 42.4 mg/L and 0.71 (0.65-0.77) for the group with calcium levels of 42.6 mg/L or more. After adjustment for calcium levels in drinking water, there was no difference between the groups with different levels of magnesium. The results of the present study show that there is a significant protective effect of calcium intake from drinking water on the risk of death from AMI.

  9. In situ synthesis of magnesium-substituted biphasic calcium phosphate and in vitro biodegradation

    SciTech Connect

    Kim, Tae-Wan; Lee, Hyeong-Shin; Kim, Dong-Hyun; Jin, Hyeong-Ho; Hwang, Kyu-Hong; Lee, Jong Kook; Park, Hong-Chae; Yoon, Seog-Young

    2012-09-15

    Highlights: ► Mg–BCP were successfully prepared through in situ aqueous co-precipitation method. ► The amount of β-TCP phase was changed with the magnesium substitution level. ► The substitution of magnesium led to a decrease in the unit cell volume. ► Mg–BCP could be able to develop a new apatite phase on the surface faster than BCP. -- Abstract: In situ preparation of magnesium (Mg) substituted biphasic calcium phosphate (BCP) of hydroxyapatite (HAp)/β-tricalcium phosphate (β-TCP) were carried out through aqueous co-precipitation method. The concentrations of added magnesium were varied with the calcium in order to obtain constant (Ca + Mg)/P ratios of 1.602. X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy were used to characterize the structure of synthesized magnesium substituted BCP powders. The results have shown that substitution of magnesium in the calcium deficient apatites revealed the formation of biphasic mixtures of different HAp/β-TCP ratios after heating at 1000 °C. The ratios of the formation of phase mixtures were dependent on the content of magnesium. After immersing in Hanks’ balanced salt solution (HBSS) for 1 week, 1 wt% magnesium substituted BCP powders were degraded and precipitation started to be formed with small granules consisting of number of flake-like crystal onto the surface of synthesized powders. On the other hand, in the case of pure BCP powders, the formation of new precipitates was detected after immersion in HBSS for 2 weeks. On the basis of these results, magnesium substituted BCP could be able to develop a new apatite phase on the surface in contact with physiological fluids faster than BCP does. In addition, the retention time to produce the new apatite phase in implantation operation for the BCP powder could be controlled by the amount of magnesium substitution.

  10. THE EFFECT OF EXTERNAL CALCIUM AND MAGNESIUM DEPLETION ON SINGLE NERVE FIBERS

    PubMed Central

    Adelman, William J.

    1956-01-01

    The three types of motor axons found in the walking legs of the lobster were shown to respond differently upon exposure to calcium-free solutions. While all fiber types became more excitable initially in calcium-free solutions, only openers became spontaneously active. Fast closers showed the least reduction in rheobase value upon calcium depletion. After 5 minutes in calcium-free solution all fibers showed a rise in rheobase value, and more rapid accommodation. A natural period for spontaneous firing of opener fibers was disclosed. Following such a spontaneous discharge, low amplitude rhythmical potentials were recorded. These small potentials had the same period as the spontaneous spikes. The role of calcium ion in the excitable process was discussed. Magnesium ion was shown to act synergistically with calcium ion. All fiber types became spontaneously active in solutions deprived of both calcium and magnesium. Subsequent hypoexcitability was more pronounced in calcium- and magnesium-depleted solutions than it was in only calcium-depleted solutions. PMID:13319660

  11. Calcium, magnesium, and nitrate in drinking water and gastric cancer mortality.

    PubMed

    Yang, C Y; Cheng, M F; Tsai, S S; Hsieh, Y L

    1998-02-01

    The possible association between the risk of gastric cancer and the levels of calcium, magnesium, and nitrate in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. Records of gastric cancer deaths among eligible residents in Taiwan from 1987 through 1991 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair-matched to the cases by sex, year-of-birth, and year-of-death. Each matched control was selected randomly from the set of possible controls for each case. Data on calcium, magnesium, and nitrate levels in drinking water throughout Taiwan were obtained from the Taiwan Water Supply Corporation. The municipality of residence of the cases and controls was assumed to be the source of the subject's calcium, magnesium, and nitrate exposure via drinking water. The subjects were divided into tertiles according to the levels of calcium, magnesium, and nitrate in their drinking water. The results of the present study show that there is a significant positive association between drinking water nitrate exposure and gastric cancer mortality. The present study also suggests that there was a significant protective effect of calcium intake from drinking water on the risk of gastric cancer. Magnesium also exerts a protective effect against gastric cancer, but only for the group with the highest levels.

  12. Simultaneous determination of calcium and magnesium by derivative spectrophotometry in pharmaceutical products

    NASA Astrophysics Data System (ADS)

    Benamor, M.; Aguerssif, N.

    2008-02-01

    First- and second-derivative spectrophotometric methods for the simultaneous determination of calcium and magnesium in their mixtures are described. The methods are based on the colored complexes formed by calcium and magnesium with bromopyrogallol red in presence of Tween 80 as a surfactant. The zero-crossing method has been utilized to measure the first- and second-derivative value of the derivative spectrum. Calcium (0.8-4.8 μg ml -1) is determined in the presence of magnesium (0.5-3.5 μg ml -1) at the pH 10 and vice versa at zero-crossing wavelengths of 544.5 and 570 nm in the first-derivative procedure and 574 and 531 nm in the second-derivative procedure, respectively. The detection limits achieved were 0.0575 μg ml -1 of calcium and 0.03 μg ml -1 of magnesium. The relative standard deviations were in all instances less than 2%. The proposed method has been applied to the simultaneous determination of calcium and magnesium in different samples: commercial multivitamin, human serum and drinking water where excellent agreement between reported and obtained results was achieved.

  13. A brief review of calcium phosphate conversion coating on magnesium and its alloys

    NASA Astrophysics Data System (ADS)

    Zaludin, Mohd Amin Farhan; Jamal, Zul Azhar Zahid; Jamaludin, Shamsul Baharin; Derman, Mohd Nazree

    2016-07-01

    Recent developments have shown that magnesium is a promising candidate to be used as a biomaterial. Owing to its light weight, biocompatibility and compressive strength comparable with natural bones makes magnesium as an excellent choice for biomaterial. However, high reactivity and low corrosion resistance properties have restricted the application of magnesium as biomaterials. At the moment, several strategies have been developed to solve this problem. Surface modification of magnesium is one of the popular solutions to solve the problem. Among many techniques developed in the surface modification, conversion coating method is one of the simple and effective techniques. From various types of conversion coating, calcium phosphate-based conversion coating is the most suitable for biomedical fields. This paper reviews some studies on calcium phosphate coating on Mg and its alloys via chemical conversion method and discusses some factors determining the coating performance.

  14. Is Mg-stabilized amorphous calcium carbonate a homogeneous mixture of amorphous magnesium carbonate and amorphous calcium carbonate?

    PubMed

    Yang, Sheng-Yu; Chang, Hsun-Hui; Lin, Cang-Jie; Huang, Shing-Jong; Chan, Jerry C C

    2016-10-04

    We find two types of carbonate ions in Mg stabilized amorphous calcium carbonate (Mg-ACC), whose short-range orders are identical to those of ACC and amorphous magnesium carbonate (AMC). Mg-ACC comprises a homogeneous mixture of the nano-clusters of ACC and AMC. Their relative amount varies systematically at different pH.

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

    PubMed

    Elmore, Amy R

    2003-01-01

    This report reviews the safety of Aluminum, Calcium, Lithium Magnesium, Lithium Magnesium Sodium, Magnesium Aluminum, Magnesium, Sodium Magnesium, and Zirconium Silicates, Magnesium Trisilicate, Attapulgite, Bentonite, Fuller's Earth, Hectorite, Kaolin, Montmorillonite, Pyrophyllite, and Zeolite as used in cosmetic formulations. The common aspect of all these claylike ingredients is that they contain silicon, oxygen, and one or more metals. Many silicates occur naturally and are mined; yet others are produced synthetically. Typical cosmetic uses of silicates include abrasive, opacifying agent, viscosity-increasing agent, anticaking agent, emulsion stabilizer, binder, and suspending agent. Clay silicates (silicates containing water in their structure) primarily function as adsorbents, opacifiers, and viscosity-increasing agents. Pyrophyllite is also used as a colorant. The International Agency for Research on Cancer has ruled Attapulgite fibers >5 microm as possibly carcinogenic to humans, but fibers <5 microm were not classified as to their carcinogenicity to humans. Likewise, Clinoptilolite, Phillipsite, Mordenite, Nonfibrous Japanese Zeolite, and synthetic Zeolites were not classified as to their carcinogenicity to humans. These ingredients are not significantly toxic in oral acute or short-term oral or parenteral toxicity studies in animals. Inhalation toxicity, however, is readily demonstrated in animals. Particle size, fibrogenicity, concentration, and mineral composition had the greatest effect on toxicity. Larger particle size and longer and wider fibers cause more adverse effects. Magnesium Aluminum Silicate was a weak primary skin irritant in rabbits and had no cumulative skin irritation in guinea pigs. No gross effects were reported in any of these studies. Sodium Magnesium Silicate had no primary skin irritation in rabbits and had no cumulative skin irritation in guinea pigs. Hectorite was nonirritating to the skin of rabbits in a Draize primary skin

  16. [Impact of drinking water calcium and magnesium levels on morbidity in the Omsk Region].

    PubMed

    Erofeev, Iu V; Neskin, T A; Turchaninov, D V

    2006-01-01

    Drinking water calcium and magnesium levels were examined for impact on morbidity in a model rural area of a West Siberian region. It was ascertained that there were negative correlations between the water levels of the above elements and the incidence of respiratory, gastrointestinal, and locomotor diseases and positive correlations between the concentrations of calcium and magnesium and the incidence of nervous, urogenital, and eye diseases. It is concluded that by adjusting the findings, the medical care availability factor should be taken into account in the investigations using the health indices calculated on the data from official medical accounts. This investigation has shown the estimation of the drinking water levels of calcium and magnesium as a significant hygienic problem for a model region.

  17. Determination of calcium, magnesium and zinc in unused lubricating oils by atomic absorption spectroscopy.

    PubMed

    Udoh, A P

    1995-12-01

    Varying concentrations of lanthanum and strontium were added to solutions of ashed unused lubricating oils for the determination of calcium, magnesium and zinc content using flame atomic absorption spectrophotometry. At least 3000 mug g(-1) of lanthanum or strontium was required to completely overcome the interference of the phosphate ion, PO(3-)(4), and give peak values for calcium. The presence of lanthanum or strontium did not cause an appreciable increase in the amount of magnesium and zinc obtained from the analyses. The method is fast and reproducible, and the coefficients of variation calculated for the elements using one of the samples were 1.6% for calcium, 3.5% for magnesium and 0.2% for zinc. Results obtained by this method were better than those obtained by other methods for the same samples.

  18. [Determination of calcium and magnesium in wheat flour by suspension sampling-flame atomic absorption spectrometry].

    PubMed

    Liu, L; Zhang, Q; Hu, Y

    1999-06-01

    Suspension sampling technique was applied to flame atomic absorption spectrometry and was successfully used to determine calcium and magnesium in wheat flour. The wheat flour was suspended in agar sol containing dibutyl phthalate and made into suspension. Choice of suspension agent and elimination of chemical interference were studied. The test solution was injected into air-acetylene flame to determine calcium and magnesium by standard addition method. Determination results were consistent with those obtained by ashing method. The t-test showed that no difference was found between the two methods. Displacement of ashing method by suspension sampling method for the sample pretreatment is possible. This method is convenient, rapid and accurate.

  19. Calcium and magnesium in drinking water and risk of death from kidney cancer.

    PubMed

    Chiu, Hui-Fen; Chang, Chih-Ching; Chen, Chih-Cheng; Yang, Chun-Yuh

    2011-01-01

    The possible association between the risk of kidney cancer development and the levels of calcium and magnesium in drinking water from municipal supplies was investigated in a matched cancer case-control study in Taiwan. All eligible kidney cancer deaths (1778 cases) of Taiwan residents from 1999 through 2008 were compared with deaths from other causes (1778 controls), and the levels of calcium and magnesium in drinking water of these residents were determined. Data on calcium and magnesium levels in drinking water throughout Taiwan were obtained from the Taiwan Water Supply Corporation (TWSC). The control group consisted of individuals who died from other causes, and the controls were pair-matched to the cancer cases by gender, year of birth, and year of death. The adjusted odd ratios for death attributed to kidney cancer for individuals with higher calcium levels in their drinking water, as compared to the lowest tertile, were 0.89 (95% CI = 0.72-1.11) and 0.78 (95% CI = 0.62-0.98), respectively. The adjusted odd ratios were not statistically significant for the relationship between magnesium levels in drinking water and kidney cancer development. The results of the present study demonstrate that there may be a significant protective effect of calcium intake from drinking water against the risk of death due to kidney cancer.

  20. Effects of magnesium salts in preventing experimental oxalate urolithiasis in rats.

    PubMed

    Ogawa, Y; Yamaguchi, K; Morozumi, M

    1990-08-01

    Magnesium oxide, magnesium hydroxide, magnesium sulfate, magnesium trisilicate, and magnesium citrate were added to a calcium-oxalate lithogenic diet in order to determine their effects in preventing lithogenesis. Male Wistar-strain rats which had been fed the glycolic-acid diet developed marked urinary calculi within four weeks. Rats in the magnesium-hydroxide, magnesium-citrate, and magnesium-trisilicate groups, however, had almost no stones in the urinary system. Rats in the magnesium-oxide and magnesium-sulfate groups showed significantly less effect than those in the former three groups. During the experimental period, the 24-hour urinary oxalate excretion and concentration were higher in the glycolic-acid group than in the other groups. The urinary citrate excretion and concentration were the highest in the magnesium-hydroxide and magnesium-citrate groups and higher in the magnesium-trisilicate and magnesium-oxide groups than in the magnesium-sulfate and glycolic-acid groups. Similar trends were observed in the urinary magnesium excretion and in its concentration. The urinary calcium excretion and concentration were higher in the experimental groups than in the glycolic-acid group. The urinary calcium/magnesium ratio remained mostly unchanged. Therefore, it can be concluded that alkaline magnesium salts increase the urinary calcium and magnesium concentrations, without changing the calcium/magnesium ratio, and inhibit urinary calculi formation, most likely by increasing the urinary citrate concentration.

  1. Perturbation Analysis of Calcium, Alkalinity and Secretion during Growth of Lily Pollen Tubes

    PubMed Central

    Winship, Lawrence J.; Rounds, Caleb; Hepler, Peter K.

    2016-01-01

    Pollen tubes grow by spatially and temporally regulated expansion of new material secreted into the cell wall at the tip of the tube. A complex web of interactions among cellular components, ions and small molecule provides dynamic control of localized expansion and secretion. Cross-correlation studies on oscillating lily (Lilium formosanum Wallace) pollen tubes showed that an increase in intracellular calcium follows an increase in growth, whereas the increase in the alkaline band and in secretion both anticipate the increase in growth rate. Calcium, as a follower, is unlikely to be a stimulator of growth, whereas the alkaline band, as a leader, may be an activator. To gain further insight herein we reversibly inhibited growth with potassium cyanide (KCN) and followed the re-establishment of calcium, pH and secretion patterns as growth resumed. While KCN markedly slows growth and causes the associated gradients of calcium and pH to sharply decline, its removal allows growth and vital processes to fully recover. The calcium gradient reappears before growth restarts; however, it is preceded by both the alkaline band and secretion, in which the alkaline band is slightly advanced over secretion. Thus the pH gradient, rather than the tip-focused calcium gradient, may regulate pollen tube growth. PMID:28042810

  2. Bioactive calcium phosphate coating formed on micro-arc oxidized magnesium by chemical deposition

    NASA Astrophysics Data System (ADS)

    Liu, G. Y.; Hu, J.; Ding, Z. K.; Wang, C.

    2011-01-01

    In order to improve the bioactivity of the micro-arc oxidized magnesium, a calcium phosphate coating was formed on the surface of micro-arc oxidized magnesium using a chemical method. The microstructures of the substrate and the calcium phosphate coating before and after the simulated body fluids (SBF) incubation were characterized by X-ray diffraction, Fourier-transformed infrared spectroscopy and scanning electron microscopy. The results showed that the calcified coating was composed of calcium deficient hydroxyapatite (HA) and dicalcium phosphate dihydrate (DCPD). After SBF incubation, some new apatite formation on the calcified coating surface from SBF could be found. The corrosion behaviours of the samples in SBF were also investigated by potentiodynamic polarization curves and immersion tests. The results showed that calcium phosphate coating increased the corrosion potential, and decreased the hydrogen gas release.

  3. The initial phases of calcium and magnesium phosphates precipitated from solutions of high to medium concentrations

    NASA Astrophysics Data System (ADS)

    Abbona, F.; Madsen, H. E. Lundager; Boistelle, R.

    1986-04-01

    The precipitation of calcium and magnesium phosphates is performed at 25°C by mixing solutions of ammonium phosphate and solutions of calcium and magnesium chlorides under the condition [ P] = [ Ca] + [ Mg] in large pH intervals. Before any nucleation the phosphate concentration ranges from 0.50M to 0.01M. The phases first precipitated are CaHPO 4·2H 2O (brushite), CaHPO 4 (monetite), Ca 3(PO 4) 2· xH 2O (amorphous calcium phosphate), MgNH 4PO 4·6H 2O (struvite), and MgHPO 4·3H 2O (newberyite). The precipitation fields of each phase are determined and discussed as a function of pH, composition and supersaturation. The solutions are even supersaturated with respect to several other calcium phosphates but they never occur first even if their supersaturation is the highest.

  4. Variations of Dietary Salt and Fluid Modulate Calcium and Magnesium Transport in Renal Distal Tubule

    PubMed Central

    Lee, Chien-Te; Lien, Yeong-Hau H; Lai, Li-Wen; Ng, Hwee-Yeong; Chiou, Terry Ting-Yu; Chen, Hung-Chun

    2014-01-01

    Background The renal distal tubule serves as the fine tuning of renal epithelial calcium transport. Dietary intake of salt and fluid varies day to day and the kidney adapts accordingly to maintain the homeostasis. The alternations in salt and fluid balance affect calcium and magnesium transport in the distal tubule, but the mechanisms are not fully understood. Methods Sprague-Dawley rats were grouped into high salt, low salt and dehydration treatment. Daily intake, water consumption and urine output were recorded. At the end of experiment, blood and urine samples were collected for hormonal and biochemical testes. Genetic analysis, immunoblotting, and immunofluorescence studies were then performed to assess the alterations of calcium and magnesium transport-related molecules. Results High salt treatment increased urinary sodium, calcium and magnesium excretion. Low salt treatment and dehydration were associated with decreased urinary excretion of all electrolytes. High salt treatment was associated with increased intact parathyroid hormone levels. Significant increase in gene expression of TRPV5, TRPV6, calbindin-D28k and TRPM6 was found during high salt treatment while low salt and dehydration diminished the expression. These findings were confirmed with immunofluorescence studies. High salt and low salt intake or dehydration did not cause any significant changes in WNK1, WNK3 and WNK4. Conclusions Alternations in salt and water intake affect renal calcium and magnesium handling. High salt intake increases distal delivery of the divalent cations which upregulates distal tubule calcium and magnesium transport molecules, while the opposite effects are associated with low salt intake or dehydration. PMID:23774784

  5. Precipitation of calcium, magnesium, strontium and barium in tissues of four Acacia species (Leguminosae: Mimosoideae).

    PubMed

    He, Honghua; Bleby, Timothy M; Veneklaas, Erik J; Lambers, Hans; Kuo, John

    2012-01-01

    Precipitation of calcium in plants is common. There are abundant studies on the uptake and content of magnesium, strontium and barium, which have similar chemical properties to calcium, in comparison with those of calcium in plants, but studies on co-precipitation of these elements with calcium in plants are rare. In this study, we compared morphologies, distributional patterns, and elemental compositions of crystals in tissues of four Acacia species grown in the field as well as in the glasshouse. A comparison was also made of field-grown plants and glasshouse-grown plants, and of phyllodes of different ages for each species. Crystals of various morphologies and distributional patterns were observed in the four Acacia species studied. Magnesium, strontium and barium were precipitated together with calcium, mainly in phyllodes of the four Acacia species, and sometimes in branchlets and primary roots. These elements were most likely precipitated in forms of oxalate and sulfate in various tissues, including epidermis, mesophyll, parenchyma, sclerenchyma (fibre cells), pith, pith ray and cortex. In most cases, precipitation of calcium, magnesium, strontium and barium was biologically induced, and elements precipitated differed between soil types, plant species, and tissues within an individual plant; the precipitation was also related to tissue age. Formation of crystals containing these elements might play a role in regulating and detoxifying these elements in plants, and protecting the plants against herbivory.

  6. Precipitation of Calcium, Magnesium, Strontium and Barium in Tissues of Four Acacia Species (Leguminosae: Mimosoideae)

    PubMed Central

    He, Honghua; Bleby, Timothy M.; Veneklaas, Erik J.; Lambers, Hans; Kuo, John

    2012-01-01

    Precipitation of calcium in plants is common. There are abundant studies on the uptake and content of magnesium, strontium and barium, which have similar chemical properties to calcium, in comparison with those of calcium in plants, but studies on co-precipitation of these elements with calcium in plants are rare. In this study, we compared morphologies, distributional patterns, and elemental compositions of crystals in tissues of four Acacia species grown in the field as well as in the glasshouse. A comparison was also made of field-grown plants and glasshouse-grown plants, and of phyllodes of different ages for each species. Crystals of various morphologies and distributional patterns were observed in the four Acacia species studied. Magnesium, strontium and barium were precipitated together with calcium, mainly in phyllodes of the four Acacia species, and sometimes in branchlets and primary roots. These elements were most likely precipitated in forms of oxalate and sulfate in various tissues, including epidermis, mesophyll, parenchyma, sclerenchyma (fibre cells), pith, pith ray and cortex. In most cases, precipitation of calcium, magnesium, strontium and barium was biologically induced, and elements precipitated differed between soil types, plant species, and tissues within an individual plant; the precipitation was also related to tissue age. Formation of crystals containing these elements might play a role in regulating and detoxifying these elements in plants, and protecting the plants against herbivory. PMID:22848528

  7. High Calcium-Magnesium Ratio in Hair Is Associated with Coronary Artery Calcification in Middle-Aged and Elderly Individuals.

    PubMed

    Park, Byoungjin; Kim, Mi-Hyun; Cha, Choong Keun; Lee, Yong-Jae; Kim, Kyong-Chol

    2017-02-06

    The interaction between calcium and magnesium as a risk modifier for cardiovascular disease (CVD) has been largely overlooked in previous studies, for the strict regulatory system in blood has been thought to keep such homeostatic interactions under tight control. This study aimed to investigate the association between calcium-magnesium ratio in hair and subclinical coronary artery calcification. Using multiple linear regression analysis, we examined the associations between calcium-magnesium ratio in hair and the coronary calcium score (CCS) in 216 Koreans aged 40 years and above (122 men and 94 women). We found that the calcium-to-magnesium ratio in hair was independently and positively associated with CCS after adjusting for age and sex (regression coefficient 6.051 ± 2.329, P = 0.010). When we assessed the association between the calcium-magnesium ratio and CCS after adjusting for potential cardiovascular risk factors and vascular function modifying drugs, we found that the strength of association with CCS was comparable to before (regression coefficient 5.434 ± 2.523, P = 0.032). Our findings suggest that among middle-aged and elderly Koreans without clinical CVD, the association between coronary artery calcification and hair calcium-magnesium ratio is stronger in those with a higher calcium-magnesium ratio in hair than in those with a lower ratio.

  8. Nitrogen, phosphorus, potassium, calcium, magnesium, and zinc in southeastern USA harvested flax

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flax (Linum usitatissimum L.) is a winter crop in the Southeast USA that has potential in double cropping systems. This research was conducted to provide estimates of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and zinc (Zn) removal in the harvested portions of the cro...

  9. Egg yolk protein and egg yolk phosvitin inhibit calcium, magnesium, and iron absorptions in rats.

    PubMed

    Ishikawa, S-I; Tamaki, S; Arihara, K; Itoh, M

    2007-08-01

    Egg yolk decreases the absorption of iron. The effects of egg yolk protein and egg yolk phosvitin on the absorption of calcium, magnesium, and iron were investigated by in vivo studies. Male Wistar rats were fed purified diets containing casein, soy protein, or egg yolk protein for 14 d. The apparent absorptions of calcium, magnesium, and iron in the rats fed the yolk protein-based diet were lower than those in rats fed the casein- and soy protein-based diets. The apparent phosphorus absorption and the apparent protein digestibility in the yolk protein group were lower than those in the casein and soy protein groups. In the feces of the yolk protein group, serine comprised more than 30% of the amino acids. The addition of egg yolk phosvitin to the casein diets at levels of 1% and 2% (w/w) produced effects on calcium and magnesium absorptions similar to those produced by the diet containing yolk protein. The tricine sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) pattern suggested that phosphopeptide fragments having molecular masses of 28, 22, and 15 kDa were evident in the contents of the small intestine of the rats fed phosvitin diets. These results indicate that yolk protein, when compared with casein and soy protein, decreases calcium and magnesium absorption via the resistance of phosvitin to proteolytic action.

  10. Effects of calcium magnesium acetate on the combustion of coal-water slurries

    SciTech Connect

    Levendis, Y.A.

    1991-01-01

    The general objective of the project is to investigate the combustion behavior of single and multiple Coal-Water Fuel (CWF) particles burning at high temperature environments. Both uncatalyzed as well as catalyzed CWF drops with Calcium Magnesium Acetate (CMA) catalyst will be studies. Emphasis will also be given in the effects of CMA on the sulfur capture during combustion.

  11. Impact of Testosterone, Zinc, Calcium and Magnesium Concentrations on Sperm Parameters in Subfertile Men

    NASA Astrophysics Data System (ADS)

    Aydemir, Birsen; Kiziler, Ali Riza; Onaran, Ilhan; Alici, Bülent; Özkara, Hamdi; Akyolcu, Mehmet Can

    2007-04-01

    To investigate the impact of testosterone, zinc, calcium and magnesium concentrations in serum and seminal plasma on sperm parameters. There were significant decrease in sperm parameters, serum and seminal plasma zinc levels in subfertile males. It indicates zinc has a essential role in male infertility; the determination the level of zinc during infertility investigation is recommended.

  12. Effect of polyphenols on calcium content and alkaline phosphatase activity in rat femoral tissues in vitro.

    PubMed

    Yamaguchi, M; Jie, Z

    2001-12-01

    The effect of various polyphenols on calcium content and alkaline phosphatase activity in the femoral-diaphyseal and -metaphyseal tissues of young rats in vitro was investigated. Bone tissues were cultured for 24 h in serum-free Dulbecco's modified Eagle's medium containing either vehicle or various polyphenols (10(-7) - 10(-4) M). The presence of genistein (10(-6) - 10(-4) M) caused a significant increase in calcium content and alkaline phosphatase activity in the femoral-diaphyseal and -metaphyseal tissues. Resveratrol (10(-4) m) decreased metaphyseal calcium content significantly, and it (10(-6) - 10(-4) M) had a significant inhibitory effect on diaphyseal enzyme activity. Epigallocatechin gallate (EGCg; 10(-4) M) significantly inhibited alkaline phosphatase activity in the diaphyseal and metaphyseal tissues. EGCg (10(-7) - 10(-4) M) had no effect on bone calcium content. Meanwhile, glycitein, quercetin, or catechin in the range of 10(-7) to 10(-4) ml did not have an effect on calcium content and alkaline phosphatase activity in the femoral-diaphyseal and -metaphyseal tissues. The present study suggests that a phytoestrogen genistein has a unique anabolic effect on bone calcification in vitro.

  13. Nanostructured calcium phosphate coatings on magnesium alloys: characterization and cytocompatibility with mesenchymal stem cells

    PubMed Central

    Iskandar, Maria Emil; Aslani, Arash; Tian, Qiaomu

    2016-01-01

    This article reports the deposition and characterization of nanostructured calcium phosphate (nCaP) on magnesium–yttrium alloy substrates and their cytocompatibility with bone marrow derived mesenchymal stem cells (BMSCs). The nCaP coatings were deposited on magnesium and magnesium–yttrium alloy substrates using proprietary transonic particle acceleration process for the dual purposes of modulating substrate degradation and BMSC adhesion. Surface morphology and feature size were analyzed using scanning electron microscopy and quantitative image analysis tools. Surface elemental compositions and phases were analyzed using energy dispersive X-ray spectroscopy and X-ray diffraction, respectively. The deposited nCaP coatings showed a homogeneous particulate surface with the dominant feature size of 200–500 nm in the long axis and 100–300 nm in the short axis, and a Ca/P atomic ratio of 1.5–1.6. Hydroxyapatite was the major phase identified in the nCaP coatings. The modulatory effects of nCaP coatings on the sample degradation and BMSC behaviors were dependent on the substrate composition and surface conditions. The direct culture of BMSCs in vitro indicated that multiple factors, including surface composition and topography, and the degradation-induced changes in media composition, influenced cell adhesion directly on the sample surface, and indirect adhesion surrounding the sample in the same culture. The alkaline pH, the indicator of Mg degradation, played a role in BMSC adhesion and morphology, but not the sole factor. Additional studies are necessary to elucidate BMSC responses to each contributing factor. PMID:25917827

  14. Serum Calcium, Magnesium, Zinc and Copper Levels in Sudanese Women with Preeclampsia

    PubMed Central

    Elmugabil, Abdelmageed; Hamdan, Hamdan Z.; Elsheikh, Anas E.; Rayis, Duria A.; Gasim, Gasim I.

    2016-01-01

    Background Although the exact pathophysiology of preeclampsia is not fully understood, several elemental micronutrient abnormalities have been suggested to play a contributory role in preeclampsia. Aims To investigate the levels of calcium, magnesium, zinc and copper in women with preeclampsia. Subjects and Methods A case—control study was conducted in Omdurman Maternity Hospital, Sudan, during the period of September through December 2014. The cases were women with preeclampsia while healthy pregnant women were the controls. The medical and obstetrics history was gathered using questionnaires. The serum levels of calcium, magnesium, zinc and copper were measured using atomic absorption spectrophotometer. Results There was no significant difference between the two groups in their age, gestational age, parity and body mass index. Zinc and copper levels were not significantly different between the two groups. In comparison with the controls, women with preeclampsia had a significantly lower median (inter-quartile) serum calcium [7.6 (4.0─9.6) vs. 8.1 (10.6─14.2), mg/dl, P = 0.032] and higher levels of magnesium [1.9 (1.4─2.5) vs. 1.4 (1.0─1.9) mg/dl; P = 0.003]. In binary logistic regression, lower calcium (OR = 0.73, 95% CI = 0.56 ─ 0.95, P = 0.021) and higher magnesium (OR = 5.724, 95% CI = 1.23 ─ 26.50, P = 0.026) levels were associated with preeclampsia. There were no significant correlations between levels of hemoglobin and these trace elements. Conclusion The current study showed significant associations between preeclampsia and serum levels of calcium and magnesium. PMID:27911936

  15. Americium and plutonium association with magnesium hydroxide colloids in alkaline nuclear industry process environments

    NASA Astrophysics Data System (ADS)

    Maher, Zoe; Ivanov, Peter; O'Brien, Luke; Sims, Howard; Taylor, Robin J.; Heath, Sarah L.; Livens, Francis R.; Goddard, David; Kellet, Simon; Rand, Peter; Bryan, Nick D.

    2016-01-01

    The behaviours of Pu, Am and colloids in feed solutions to the Site Ion-exchange Effluent Plant (SIXEP) at the Sellafield nuclear reprocessing site in the U.K. have been studied. For both Pu and Am, fractions were found to be associated with material in the colloidal size range, with ˜50% of the Pu in the range 1-200 nm. The concentration of soluble Pu (<1 nm) was ˜1 nM, which is very similar to the solubility limit for Pu(V). The soluble Am concentration was of the order of 10-11 M, which was below the solubility limit of americium hydroxide. The size, morphology and elemental composition of the particulates and colloids in the feed solutions were investigated. Magnesium is homogeneously distributed throughout the particles, whereas U, Si, Fe, and Ca were present in localised areas only. Amongst some heterogeneous material, particles were identified that were consistent with hydrotalcite. The distribution of 241Am(III) on brucite (magnesium hydroxide) colloids of different sizes was studied under alkaline conditions representative of nuclear fuel storage pond and effluent feed solution conditions. The morphology of the brucite particles in the bulk material observed by ESEM was predominantly hexagonal, while that of the carbonated brucite consisted of hexagonal species mixed with platelets. The association of 241Am(III) with the brucite colloids was studied by ultrafiltration coupled with gamma ray-spectrometry. For carbonate concentrations up to 10-3 M, the 241Am(III) was mainly associated with larger colloids (>300 kDa), and there was a shift from the smaller size fractions to the larger over a period of 6 months. At higher carbonate concentrations (10-2 M), the Am was predominantly detected in the true solution fraction (<3 kDa) and in smaller size colloidal fractions, in the range 3-100 kDa.

  16. Potassium, calcium, and magnesium intakes and risk of stroke in women.

    PubMed

    Larsson, Susanna C; Virtamo, Jarmo; Wolk, Alicja

    2011-07-01

    The authors examined the association between dietary potassium, calcium, and magnesium intakes and the incidence of stroke among 34,670 women 49-83 years of age in the Swedish Mammography Cohort who completed a food frequency questionnaire in 1997. The authors used Cox proportional hazards regression models to estimate relative risks and 95% confidence intervals. During a mean follow-up of 10.4 years (1998-2008), 1,680 stroke events were ascertained, including 1,310 cerebral infarctions, 154 intracerebral hemorrhages, 79 subarachnoid hemorrhages, and 137 unspecified strokes. There was no overall association between potassium, calcium, or magnesium intake and the risk of any stroke or cerebral infarction. However, among women with a history of hypertension, potassium intake was inversely associated with risk of all types of stroke (for highest vs. lowest quintile, adjusted relative risk = 0.64, 95% confidence interval (CI): 0.45, 0.92) and cerebral infarction (corresponding adjusted relative risk = 0.56, 95% CI: 0.38, 0.84), and magnesium intake was inversely associated with risk of cerebral infarction (corresponding adjusted relative risk = 0.63, 95% CI: 0.42, 0.93). Calcium intake was positively associated with risk of intracerebral hemorrhage (for highest vs. lowest tertile, adjusted relative risk = 2.04, 95% CI: 1.24, 3.35). These findings suggest that potassium and magnesium intakes are inversely associated with the risk of cerebral infarction among hypertensive women.

  17. Groundwater chemistry and cation budgets of tropical karst outcrops, Peninsular Malaysia, I. Calcium and magnesium

    NASA Astrophysics Data System (ADS)

    Crowther, J.

    1989-05-01

    The discharge and chemical properties of 217 autogenic groundwaters were monitored over a 1-yr period in the tower karsts of central Selangor and the Kinta Valley, and in the Setul Boundary Range. Because of differences in soil PCO 2, calcium concentrations are significantly higher in the Boundary Range (mean, 82.5 mg l -1) than in the tower karst terrain (44.6 mg l -1). Local differences in both source area PCO 2 and amounts of secondary deposition underground cause marked intersite variability, particularly in the tower karst. Dilution occurs during flood peaks in certain conduit and cave stream waters. Generally, however, calcium correlates positively with discharge, since the amount of secondary deposition per unit volume of water decreases at higher flows. Magnesium concentrations and Mg:Ca + Mg ratios of groundwaters are strongly influenced by bedrock composition, though bedrock heterogeneity and the kinetics and equilibria of carbonate dissolution reactions preclude extremely low or high Mg:Ca + Mg values. Net chemical denudation rates range from 56.6 to 70.9 m 3km 2yr -1. The results are considered in relation to cation fluxes in surface runoff, soil throughflow and nutrient cycling. Preliminary calcium and magnesium budgets show that (1) dissolutional activity is largely confined to the near-surface zone; and (2) the annual uptake of calcium and magnesium by tropical limestone forests is similar in magnitude to the net solute output in groundwaters.

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

    PubMed

    Karppanen, H; Karppanen, P; Mervaala, E

    2005-12-01

    The present average sodium intakes, approximately 3000-4500 mg/day in various industrialised populations, are very high, that is, 2-3-fold in comparison with the current Dietary Reference Intake (DRI) of 1500 mg. The sodium intakes markedly exceed even the level of 2500 mg, which has been recently given as the maximum level of daily intake that is likely to pose no risk of adverse effects on blood pressure or otherwise. By contrast, the present average potassium, calcium, and magnesium intakes are remarkably lower than the recommended intake levels (DRI). In USA, for example, the average intake of these mineral nutrients is only 35-50% of the recommended intakes. There is convincing evidence, which indicates that this imbalance, that is, the high intake of sodium on one hand and the low intakes of potassium, calcium, and magnesium on the other hand, produce and maintain elevated blood pressure in a big proportion of the population. Decreased intakes of sodium alone, and increased intakes of potassium, calcium, and magnesium each alone decrease elevated blood pressure. A combination of all these factors, that is, decrease of sodium, and increase of potassium, calcium, and magnesium intakes, which are characteristic of the so-called Dietary Approaches to Stop Hypertension diets, has an excellent blood pressure lowering effect. For the prevention and basic treatment of elevated blood pressure, various methods to decrease the intake of sodium and to increase the intakes of potassium, calcium, and magnesium should be comprehensively applied in the communities. The so-called 'functional food/nutraceutical/food-ceutical' approach, which corrects the mineral nutrient composition of extensively used processed foods, is likely to be particularly effective in producing immediate beneficial effects. The European Union and various governments should promote the availability and use of such healthier food compositions by tax reductions and other policies, which make the

  19. Relief of Casein Inhibition of Bacillus stearothermophilus by Iron, Calcium, and Magnesium1

    PubMed Central

    Ashton, D. H.; Busta, F. F.; Warren, J. A.

    1968-01-01

    Growth of Bacillus stearothermophilus strain NCA 1518 Smooth in Dextrose Tryptone Agar (DTA) was inhibited by sodium caseinate. Binding studies indicated that sodium caseinate, when present in DTA, had the capacity to effect an iron deficiency which could cause inhibition of growth. Additions of essential cations, iron (1 mM), calcium (5 mM), magnesium (10 mM), or hydrogen ion (pH 5.7), relieved inhibition. Responses to and interactions among these relief factors were analyzed statistically. Equations were fitted to the data and were used to estimate responses to all treatment combinations within the ranges tested. Results from these studies indicated that calcium, magnesium, and hydrogen ion acted by decreasing the binding capacity of the protein for iron, rendering this metal available for metabolic needs. Evidence was obtained that ferrous rather than ferric iron was the limiting factor in DTA containing sodium caseinate. PMID:5694503

  20. Plasma Calcium, Inorganic Phosphate and Magnesium During Hypocalcaemia Induced by a Standardized EDTA Infusion in Cows

    PubMed Central

    Mellau, LSB; Jørgensen, RJ; Enemark, JMD

    2001-01-01

    The intravenous Na2EDTA infusion technique allows effective specific chelation of circulating Ca2+ leading to a progressive hypocalcaemia. Methods previously used were not described in detail and results obtained by monitoring total and free ionic calcium were not comparable due to differences in sampling and analysis. This paper describes a standardized EDTA infusion technique that allowed comparison of the response of calcium, phosphorus and magnesium between 2 groups of experimental cows. The concentration of the Na2EDTA solution was 0.134 mol/l and the flow rate was standardized at 1.2 ml/kg per hour. Involuntary recumbency occurred when ionised calcium dropped to 0.39 – 0.52 mmol/l due to chelation. An initial fast drop of ionized calcium was observed during the first 20 min of infusion followed by a fluctuation leading to a further drop until recumbency. Pre-infusion [Ca2+] between tests does not correlate with the amount of EDTA required to induce involuntary recumbence. Total calcium concentration measured by atomic absorption remained almost constant during the first 100 min of infusion but declined gradually when the infusion was prolonged. The concentration of inorganic phosphate declined gradually in a fluctuating manner until recumbency. Magnesium concentration remained constant during infusion. Such electrolyte responses during infusion were comparable to those in spontaneous milk fever. The standardized infusion technique might be useful in future experimental studies. PMID:11503370

  1. Application of alkaline phosphatases from different sources in pharmaceutical and clinical analysis for the determination of their cofactors; zinc and magnesium ions.

    PubMed

    Muginova, Svetlana V; Zhavoronkova, Anna M; Polyakov, Alexei E; Shekhovtsova, Tatyana N

    2007-03-01

    Prospects of using different alkaline phosphatases bearing zinc and magnesium ions in their catalytic and allosteric sites, respectively, in pharmaceutical and clinical analysis were demonstrated. Also their application for the determination of zinc in insulin to control injection quality and magnesium in human urine for the diagnosis and treatment of magnesium deficiency was shown. The reaction of p-nitrophenyl phosphate hydrolysis was chosen as an indicator. The choice of appropriate alkaline phosphatase was substantiated, the influence of the nature of buffer solutions on the behavior of the enzyme-metal systems was studied, and the conditions of the indicator reaction proceeding in the presence of sample matrixes were optimized. Simple, rapid, sensitive, and selective enzymatic procedures for determining zinc and magnesium based on their inhibiting and activating effects on the catalytic activity of alkaline phosphatases from seal and chicken intestine, respectively, were developed.

  2. The effect of intravenous magnesium hypophosphite in calcium borogluconate solution on the serum concentration of inorganic phosphorus in healthy cows.

    PubMed

    Braun, U; Jehle, W

    2007-03-01

    The goal of this study was to determine the effect of intravenous (IV) administration of phosphite on the serum concentration of inorganic phosphorus in cows. Twelve clinically healthy cows were divided into four groups of three. All cows received 600 mL of a 40% calcium borogluconate solution; three cows each received this as a rapid (20 min) IV infusion with and without 6% magnesium hypophosphite, and three other cows each received this as a slow IV infusion (8 h) with and without 6% magnesium hypophosphite. Samples of blood were collected for the determination of serum concentrations of calcium, inorganic phosphorus and magnesium before and 10, 20, 40, 60 and 90 min and 2, 3, 4, 5, 6, 7, 8, 24, 48 and 72 h after the start of treatment. The concentration of calcium increased after treatment in all cows but the increase was most rapid in cows that received the rapid infusion. In cows that received the rapid IV infusion containing magnesium hypophosphite, the mean concentration of inorganic phosphorus decreased significantly 3-4 h after treatment compared with initial serum levels. The serum concentration of inorganic phosphorus did not change significantly in cows that received the rapid IV solution without magnesium hypophosphite or the slow IV infusion with or without magnesium hypophosphite. The serum concentration of magnesium increased after treatment in all cows receiving magnesium hypophosphite but remained unchanged in the others. The rapid infusion of calcium borogluconate without magnesium hypophosphite made all three cows anorexic and hypercalcaemic and the slow infusion made 1/3 anorexic. It is concluded that the IV administration of a calcium solution containing magnesium hypophosphite does not increase the serum concentration of inorganic phosphorus.

  3. Fully automated spectrophotometric procedure for simultaneous determination of calcium and magnesium in biodiesel.

    PubMed

    Shishov, Andrey Y; Nikolaeva, Larisa S; Moskvin, Leonid N; Bulatov, Andrey V

    2015-04-01

    An easily performed stepwise injection (SWIA) procedure based on on-line dilution of biodiesel samples and the formation of color-forming calcium (II) and magnesium (II) complexes with Eriochrome Black T (EBT) in an organic medium followed by spectrophotometric determination is presented. A sample of biodiesel was placed at the bottom of a mixing chamber connected to an automatic SWIA manifold. Isopropyl alcohol was used as the diluent under bubbling. The solution was submitted for on-line spectrophotometric simultaneous determination of calcium and magnesium based on the classic least-square method. The linear ranges were from 2 to 20 μg g(-1) and from 1.2 to 12 μg g(-1), and the detection limits, calculated as 3 s for a blank test (n=5), were found to be 0.6 μg g(-1) for calcium and 0.4 μg g(-1) for magnesium. The sample throughput was 30 h(-1). The method was successfully applied to the analysis of biodiesel samples.

  4. Dosimetric properties of dysprosium doped calcium magnesium borate glass subjected to Co-60 gamma ray

    SciTech Connect

    Omar, R. S. Wagiran, H. Saeed, M. A.

    2016-01-22

    Thermoluminescence (TL) dosimetric properties of dysprosium doped calcium magnesium borate (CMB:Dy) glass are presented. This study is deemed to understand the application of calcium as the modifier in magnesium borate glass with the presence of dysprosium as the activator to be performed as TL dosimeter (TLD). The study provides fundamental knowledge of a glass system that may lead to perform new TL glass dosimetry application in future research. Calcium magnesium borate glass systems of (70-y) B{sub 2}O{sub 3} − 20 CaO – 10 MgO-(y) Dy{sub 2}O{sub 3} with 0.05  mol % ≤ y ≤ 0.7  mol % of dyprosium were prepared by melt-quenching technique. The amorphous structure and TL properties of the prepared samples were determined using powder X-ray diffraction (XRD) and TL reader; model Harshaw 4500 respectively. The samples were irradiated to Co-60 gamma source at a dose of 50 Gy. Dosimetric properties such as annealing procedure, time temperature profile (TTP) setting, optimization of Dy{sub 2}O{sub 3} concentration of 0.5 mol % were determined for thermoluminescence dosimeter (TLD) reader used.

  5. Indices of intact serum parathyroid hormone and renal excretion of calcium, phosphate, and magnesium.

    PubMed Central

    Shaw, N J; Wheeldon, J; Brocklebank, J T

    1990-01-01

    Up to date reference ranges were established for fasting renal excretion of calcium, phosphorus, and magnesium on 101 healthy children aged 2-15 years. A normal range for intact parathyroid hormone was also measured. The indices of calcium and magnesium excretion showed no correlation with age or sex so that a common range for all children could be established. The 97th centile values for urinary calcium:creatinine and magnesium:creatinine ratios were 0.69 mmol:mmol and 1.05 mmol:mmol respectively. The calculated tubular maximum for phosphate/litre of glomerular filtrate (TmPO4/GFR) showed no correlation with age with a geometric mean value of 1.67 mmol/l. The normal range for intact serum parathyroid hormone for the age group was 11-35 ng/l, which is lower than the adult normal range using the same assay. There was an inverse correlation between TmPO4/GFR and intact parathyroid hormone in this group of normal children. PMID:2248530

  6. The role of calcium and magnesium in the concrete tubes of the sandcastle worm.

    PubMed

    Sun, ChengJun; Fantner, Georg E; Adams, Jonathan; Hansma, Paul K; Waite, J Herbert

    2007-04-01

    Sandcastle worms Phragmatopoma californica build mound-like reefs by sticking together large numbers of sand grains with cement secreted from the building organ. The cement consists of protein plus substantial amounts of calcium and magnesium, which are not invested in any mineral form. This study examined the effect of calcium and magnesium depletion on the structural and mechanical properties of the cement. Divalent ion removal by chelating with EDTA led to a partial collapse of cement architecture and cement dislodgement from silica surfaces. Mechanical properties examined were sand grain pull-out force, tube resistance to compression and cement adhesive force. EDTA treatment reduced sand grain pull-out forces by 60% and tube compressive strength by 50% relative to controls. EDTA lowered both the maximal adhesive force and energy dissipation of cement by up to an order of magnitude. The adhesiveness of calcium- and magnesium-depleted cement could not be restored by re-exposure to the ions. The results suggest that divalent ions play a complex and multifunctional role in maintaining the structure and stickiness of Phragmatopoma cement.

  7. The simultaneous removal of calcium, magnesium and chloride ions from industrial wastewater using magnesium-aluminum oxide.

    PubMed

    Hamidi, Roya; Kahforoushan, Davood; Fatehifar, Esmaeil

    2013-01-01

    In this article, a method for simultaneous removal of calcium, magnesium and chloride by using Mg0.80Al0.20O1.10 as a Magnesium-Aluminum oxide (Mg‒Al oxide) was investigated. Mg‒Al oxide obtained by thermal decomposition of the Mg-Al layered double hydroxide (Mg-Al LDH). The synthesized Mg‒Al oxide were characterized with respect to nitrogen physicosorption, X-ray diffraction (XRD) and field emission scan electron microscopy (FESEM) morphology. Due to high anion-exchange capacity of Mg‒Al oxide, it was employed in simultaneously removal of Cl(-), Mg(+2) and Ca(+2) from distiller waste of a sodium carbonate production factory. For this purpose, experiments were designed to evaluate the effects of quantity of Mg‒Al oxide, temperature and time on the removal process. The removal of Cl(-), Mg(+2) and Ca(+2) from wastewater was found 93.9%, 93.74% and 93.25% at 60°C after 0.5 h, respectively. Results showed that the removal of Cl(-), Mg(+2) and Ca(+2) by Mg‒Al oxide increased with increasing temperature, time and Mg‒Al oxide quantity.

  8. 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.

  9. The effect of glycine on the growth of calcium carbonate in alkaline silica gel

    NASA Astrophysics Data System (ADS)

    Gan, Xiong; He, Kunhuan; Qian, Baosong; Deng, Qin; Lu, Laixian; Wang, Yun

    2017-01-01

    Calcium carbonate was crystallized in alkaline silica gel with the presence of glycine. The crystallization proceeded with a counterdiffusion method by the reaction of calcium chloride and sodium carbonate. Optical microscopy observation showed a significant effect of glycine on the morphology control of calcite crystals. When the initial concentration of glycine was high enough (10 mg/mL, 20 mg/mL), spherical vaterite particles formed in alkaline silica gel concomitantly together with dumbbell shaped calcite particles. The in situ study by micro-Raman spectroscopy demonstrated that both vaterite and the concomitant calcite were stable phases during their growth processes since the initial appearance. A possible mechanism has been discussed to emphasize the effect of glycine on the nucleation of vaterite and the morphological control of calcite.

  10. Influence of calcium and silica on hydraulic properties of sodium montmorillonite assemblages under alkaline conditions.

    PubMed

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

    2010-03-01

    A sodium-washed montmorillonite was exposed to calcium and silica under alkaline conditions in order to gain insight into possible interactions of engineered clay barriers and cementitious leachates found in many waste storage facilities. The changes in physico-chemical properties of the material were investigated using a combination of dead-end filtration, electrophoresis and scanning electron microscopy. The results show minimal differentiation between unaltered Na-montmorillonite samples at the two pH values tested (9 and 12), with the structure of the resulting assemblages arising from repulsive tactoid interactions. The addition of calcium (50 mM) greatly decreases the size of the structural network, and in doing so, increases the hydraulic conductivity approximately 65-fold, with the effect being greatest at pH 12. Whilst the addition of silica alone (10 mM) produced little change in the hydraulic properties of montmorillonite, its combined effect with calcium produced alterations to the structural assemblages that could not be accounted for by the presence of calcium alone. The likely binding of calcium with multiple silanol groups appears to enhance the retention of water within the Na-montmorillonite assemblage, whilst still allowing the fluent passage of water. The results confirm that polyvalent cations such as Ca(2+) may have a dramatic effect on the structural and hydraulic properties of montmorillonite assemblages while the effects of solutions containing both silicate and calcium are complex and influenced by silica-cation interactions.

  11. Effect of calcium phosphate and vitamin D3 supplementation on bone remodelling and metabolism of calcium, phosphorus, magnesium and iron

    PubMed Central

    2014-01-01

    Background The aim of the present study was to determine the effect of calcium phosphate and/or vitamin D3 on bone and mineral metabolism. Methods Sixty omnivorous healthy subjects participated in the double-blind, placebo-controlled parallel designed study. Supplements were tricalcium phosphate (CaP) and cholecalciferol (vitamin D3). At the beginning of the study (baseline), all subjects documented their normal nutritional habits in a dietary record for three successive days. After baseline, subjects were allocated to three intervention groups: CaP (additional 1 g calcium/d), vitamin D3 (additional 10 μg/d) and CaP + vitamin D3. In the first two weeks, all groups consumed placebo bread, and afterwards, for eight weeks, the test bread according to the intervention group. In the last week of each study period (baseline, placebo, after four and eight weeks of intervention), a faecal (three days) and a urine (24 h) collection and a fasting blood sampling took place. Calcium, phosphorus, magnesium and iron were determined in faeces, urine and blood. Bone formation and resorption markers were analysed in blood and urine. Results After four and eight weeks, CaP and CaP + vitamin D3 supplementations increased faecal excretion of calcium and phosphorus significantly compared to placebo. Due to the vitamin D3 supplementations (vitamin D3, CaP + vitamin D3), the plasma 25-(OH)D concentration significantly increased after eight weeks compared to placebo. The additional application of CaP led to a significant increase of the 25-(OH)D concentration already after four weeks. Bone resorption and bone formation markers were not influenced by any intervention. Conclusions Supplementation with daily 10 μg vitamin D3 significantly increases plasma 25-(OH)D concentration. The combination with daily 1 g calcium (as CaP) has a further increasing effect on the 25-(OH)D concentration. Both CaP alone and in combination with vitamin D3 have no beneficial effect on bone

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

    NASA Astrophysics Data System (ADS)

    Ji, Jiajin; Dong, Xieping; Ma, Xuhui; Tang, Songchao; Wu, Zhaoying; Xia, Ji; Wang, Quanxiang; Wang, Yutao; Wei, Jie

    2014-10-01

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

  13. Serum ionized magnesium levels and ionized calcium-to-magnesium ratios in adult patients with sickle cell anemia.

    PubMed

    Zehtabchi, Shahriar; Sinert, Richard; Rinnert, Stephan; Chang, Betty; Heinis, Christian; Altura, Rachel A; Altura, Bella T; Altura, Burton M

    2004-11-01

    Low levels of total magnesium in sickle cell erythrocytes have been linked to increased sickling due to cell dehydration. We tested the null hypothesis that adult sickle cell anemia (SCA) patients have the same serum level of ionized Mg (Mg(2+)) and Ca(2+)/Mg(2+) ratio as healthy African Americans (AA) and healthy Caucasians (CAUC). We measured serum Mg(2+) and ionized calcium (Ca(2+)) with ion-selective electrodes and calculated the serum Ca(2+)/Mg(2+) ratios in patients with SCA and control groups (AA and CAUC). Seventy-four SCA patients and 61 controls were compared. SCA patients had significantly (P < 0.001) lower levels of serum Mg(2+) (0.52 +/- 0.05) compared to healthy AA (0.57 +/- 0.04) and CAUC (0.62 +/- 0.03). Eighty-six percent of the adult SCA patients had serum Mg(2+) levels below the mean for the AA group, and 96% of SCA patients were above the AA group's mean serum Ca(2+)/Mg(2+). Of the SCA patients studied, 25.6% (95% CI, 16.2-37.2%) had serum Mg(2+) levels below the racially adjusted lower limit of normal and 50% (95% CI, 38.1-61.9%) were above the upper limit of serum Ca(2+)/Mg(2+) for AA controls. By measuring serum Mg(2+) and Ca(2+), we were able to define a subset of SCA patients with hypomagnesemia and elevated Ca(2+)/Mg(2+) ratios, who may benefit from magnesium supplementation.

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

    NASA Technical Reports Server (NTRS)

    Miladinovich, Daniel S.; Zhu, Dongming

    2011-01-01

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

  15. Factors affecting ex-situ aqueous mineral carbonation using calcium and magnesium silicate minerals

    SciTech Connect

    Gerdemann, Stephen J.; Dahlin, David C.; O'Connor, William K.; Penner, Larry R.; Rush, G.E.

    2004-01-01

    Carbonation of magnesium- and calcium-silicate minerals to form their respective carbonates is one method to sequester carbon dioxide. Process development studies have identified reactor design as a key component affecting both the capital and operating costs of ex-situ mineral sequestration. Results from mineral carbonation studies conducted in a batch autoclave were utilized to design and construct a unique continuous pipe reactor with 100% recycle (flow-loop reactor). Results from the flow-loop reactor are consistent with batch autoclave tests, and are being used to derive engineering data necessary to design a bench-scale continuous pipeline reactor.

  16. Second hyperpolarizability of delta shaped disubstituted acetylene complexes of beryllium, magnesium, and calcium.

    PubMed

    Hatua, Kaushik; Nandi, Prasanta K

    2015-10-01

    Present theoretical study involves the delta shape complexes of beryllium, magnesium, and calcium where the metal atom interacts perpendicularly with disubstituted acetylene. Most of the complexes are found to be fairly stable. The dependence of second-hyperpolarizability on the basis set with increasing polarization and diffuse functions has been examined which showed the importance of 'f-type' type polarization function for heavy metal (Mg, Ca) and 'd-type' polarization function for beryllium. Larger second hyperpolarizability has been predicted for complexes having significant ground state polarization and low lying excited states favoring strong electronic coupling. Transition energy plays the most significant role in modulating the second hyperpolarizability.

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

    SciTech Connect

    Yip, C.K.; Lukey, G.C.; Deventer, J.S.J. van . E-mail: jannie@unimelb.edu.au

    2005-09-01

    Scanning electron microscopy was used to study the effects of the addition of ground granulated blast furnace slag (GGBFS) on the microstructure and mechanical properties of metakaolin (MK) based geopolymers. It was found that it is possible to have geopolymeric gel and calcium silicate hydrate (CSH) gel forming simultaneously within a single binder. The coexistence of these two phases is dependent on the alkalinity of the alkali activator and the MK / GGBFS mass ratio. It has been found that the formation of CSH gel together with the geopolymeric gel occurs only in a system at low alkalinity. In the presence of high concentrations of NaOH (> 7.5 M), the geopolymeric gel is the predominant phase formed with small calcium precipitates scattered within the binder. The coexistence of the two phases is not observed unless a substantial amount of a reactive calcium source is present initially. It is thought that voids and pores within the geopolymeric binder become filled with the CSH gel. This helps to bridge the gaps between the different hydrated phases and unreacted particles; thereby resulting in the observed increase in mechanical strength for these binders.

  18. [Calcium, magnesium, iron and zinc in drinking water and status biomarkers of these minerals among elder people from Warsaw region].

    PubMed

    Madej, Dawid; Kaluza, Joanna; Antonik, Anna; Brzozowska, Anna; Roszkowski, Wojciech

    2011-01-01

    The aim of this study was to estimate the influence of calcium, magnesium, iron and zinc contents in drinking water on chosen parameters of nutritional status of these minerals in 164 elder people, 75-80 age, living in Warsaw region. Blood, hair and saliva were collected to assess the calcium, magnesium, iron and zinc nutritional status, while the samples of drinking water were collected to determine these minerals in water Mineral concentrations in blood, hair saliva and water were assessment using the atomic spectrophotometer absorption method It was showed that contribution of drinking water to calcium, magnesium, iron and zinc intake was: 15%, 4%, 5%, 9%, respectively. The relationship between the contents of these minerals in drinking water and their levels in the blood, hair and saliva had low correlation coefficients. It probably showed that homeostasis was maintained in the human body and other factors such as demographic or lifestyle factors were important.

  19. [Urinary magnesium and its relationship to calcium in recurrent stone-formers and controls (author's transl)].

    PubMed

    Leskovar, P; Hartung, R; Siebert, A; Wellnhofer, E

    1980-07-01

    Over a period of 4--6 weeks, urine samples were collected three times daily in a group of 16 recurrent stone-formers and in a control group of 11 healthy persons and the urinary concentrations of magnesium, calcium, ionized calcium and creatinine were determined. The Mg-concentrations were distinctly lower in the group of recurrent stone-formers than in the group of healthy controls. The differences were clearly present also in the ratio Ca/Mg, but were diminished in the Mg/creatinine ratio. The Ca2+/Mg-ratio was significantly raised in the group of recurrent stone-formers (p < 0.01) because of the significantly increased Ca2+-concentration and the diminished Mg-concentration in the group of stone-patients. The correlation between the Ca-resp. Ca2+-concentration and the Mg-concentration was in both groups, in the patient and control group, high (r about 0.7).

  20. Effects of calcium, magnesium, lead, or cadmium on lipoprotein metabolism and atherosclerosis in the pigeon

    SciTech Connect

    Revis, N.W.; Major, T.C.; Horton, C.Y.

    1980-01-01

    Epidemiological and clincal studies suggest that the incidence of atherosclerosis is higher in soft-water areas than in hard-water areas. In an attempt to discern the factor(s) in drinking water that may be associated with these observations, the current studies were performed to determine the effects of several elements associated with hard (i.e., calcium and magnesium) or soft (i.e., calcium and magnesium) or soft (i.e., cadmium and lead) water in the induction and progression of atherosclerosis in the white carneau pigeon. The effect of these elements on lipoprotein metabolism was also assessed because it has been suggested that changes in the metabolism of lipoprotein may play a role in the etiology of atherosclerosis. Results show that the number and size of atherosclerotic plaques in the aorta were increased in pigeons given drinking water containing lead and/or cadmium. The effects of these elements were antagonized by the addition of calcium to drinking water containing lead and/or cadmium. Although lead and cadmium altered the profile of lipoproteins, this change did not appear to be related to an increase in the number and size of atherosclerotic plaques of the aorta. However, in pigeons treated with calcium alone the low-density lipoprotein (LDL) increased fourfold, and arteriosclerosis of the coronary arteries was observed. This result suggests that marked increases in the LDL protein may be related to arteriosclerosis of the coronary arteries. Based on these preliminary results, we suggest that lead, cadmium, and the LDL protein may be important factors in the induction and progression of atherosclerosis and arteriosclerosis in the pigeon.

  1. The Effect of Alkaline Earth Metal on the Cesium Loading of Ionsiv(R) IE-910 and IE-911

    SciTech Connect

    Fondeur, F.F.

    2001-01-16

    This study investigated the effect of variances in alkaline earth metal concentrations on cesium loading of IONSIV(R) IE-911. The study focused on Savannah River Site (SRS) ''average'' solution with varying amounts of calcium, barium and magnesium.

  2. 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... potassium sodium salt (PMN P-00-7; CAS No.125005-87-0) is subject to reporting under this section for...

  3. 40 CFR 721.2076 - D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-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... potassium sodium salt (PMN P-00-7; CAS No.125005-87-0) is subject to reporting under this section for...

  4. 40 CFR 721.2076 - D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-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... potassium sodium salt (PMN P-00-7; CAS No.125005-87-0) is subject to reporting under this section for...

  5. Rapid coating of AZ31 magnesium alloy with calcium deficient hydroxyapatite using microwave energy.

    PubMed

    Ren, Yufu; Zhou, Huan; Nabiyouni, Maryam; Bhaduri, Sarit B

    2015-04-01

    Due to their unique biodegradability, magnesium alloys have been recognized as suitable metallic implant materials for degradable bone implants and bioresorbable cardiovascular stents. However, the extremely high degradation rate of magnesium alloys in physiological environment has restricted its practical application. This paper reports the use of a novel microwave assisted coating technology to improve the in vitro corrosion resistance and biocompatibility of Mg alloy AZ31. Results indicate that a dense calcium deficient hydroxyapatite (CDHA) layer was uniformly coated on a AZ31 substrate in less than 10min. Weight loss measurement and SEM were used to evaluate corrosion behaviors in vitro of coated samples and of non-coated samples. It was seen that CDHA coatings remarkably reduced the mass loss of AZ31 alloy after 7days of immersion in SBF. In addition, the prompt precipitation of bone-like apatite layer on the sample surface during immersion demonstrated a good bioactivity of the CDHA coatings. Proliferation of osteoblast cells was promoted in 5days of incubation, which indicated that the CDHA coatings could improve the cytocompatibility of the AZ31 alloy. All the results suggest that the CDHA coatings, serving as a protective layer, can enhance the corrosion resistance and biological response of magnesium alloys. Furthermore, this microwave assisted coating technology could be a promising method for rapid surface modification of biomedical materials.

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

    PubMed

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

    2014-02-01

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

  7. Mucoadhesion on urinary bladder mucosa: the influence of sodium, calcium, and magnesium ions.

    PubMed

    Kos, M Kerec; Bogataj, M; Mrhar, A

    2010-07-01

    The aim of the present work was to establish if different cations present in the lumen of the urinary bladder at the time of application affect the mucoadhesion strength of cationic chitosan, anionic sodium carboxymethyl cellulose (NaCMC), and nonionic hydroxypropyl cellulose (HPC). The mucoadhesion strength of polymeric films was determined on pig urinary bladder mucosa. Sodium, calcium, and magnesium ions decreased the mucoadhesion strength of all three polymers except NaCMC, whose detachment forces were not influenced by the presence of sodium. Lower mucoadhesion strength in the presence of cations should be considered when drug delivery systems, for example microspheres, containing the tested mucoadhesive polymers are applied intravesically. In the majority of the experiments, cations decreased the mucoadhesion strength of the polymers already in concentrations normally present in urine. For stronger mucoadhesion, application of microspheres into the empty urinary bladder would be recommended. Additionally, the mucoadhesion properties of the tested polymers could be controlled by the selection of a proper medium for the suspension of microspheres. Namely, for all three polymers bivalent calcium and magnesium had stronger influence on mucoadhesion compared to univalent sodium, and with increasing concentrations of cations mucoadhesion strength of the polymers decreased.

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

    SciTech Connect

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

    2016-01-28

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

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

    DOE PAGES

    Le, Peisi; Fratini, Emiliano; Ito, Kanae; ...

    2016-01-28

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

  10. Determination of thermodynamic parameters for complexation of calcium and magnesium with chondroitin sulfate isomers using isothermal titration calorimetry: Implications for calcium kidney-stone research

    NASA Astrophysics Data System (ADS)

    Rodgers, Allen L.; Jackson, Graham E.

    2017-04-01

    Chondroitin sulfate (CS) occurs in human urine. It has several potential binding sites for calcium and as such may play an inhibitory role in calcium oxalate and calcium phosphate (kidney stone disease by reducing the supersaturation (SS) and crystallization of these salts. Urinary magnesium is also a role player in determining speciation in stone forming processes. This study was undertaken to determine the thermodynamic parameters for binding of the disaccharide unit of two different CS isomers with calcium and magnesium. These included the binding constant K. Experiments were performed using an isothermal titration calorimeter (ITC) at 3 different pH levels in the physiological range in human urine. Data showed that interactions between the CS isomers and calcium and magnesium occur via one binding site, thought to be sulfate, and that log K values are 1.17-1.93 and 1.77-1.80 for these two metals respectively. Binding was significantly stronger in Mg-CS than in Ca-CS complexes and was found to be dependent on pH in the latter but not in the former. Furthermore, binding in Ca-CS complexes was dependent on the location of the sulfate binding site. This was not the case in the Mg-CS complexes. Interactions were shown to be entropy driven and enthalpy unfavourable. These findings can be used in computational modeling studies to predict the effects of the calcium and magnesium CS complexes on the speciation of calcium and the SS of calcium salts in real urine samples.

  11. Analysis of serum Calcium, Magnesium, and Parathyroid Hormone in neonates delivered following preeclampsia treatment.

    PubMed

    Vahabi, S; Zaman, M; Farzan, B

    2016-12-30

    Due to the approximate clinical and biochemical manifestations of calcium and magnesium disturbances, with regard to the regulatory effects of parathyroid hormone (PTH), this present study is designed to analyze serum calcium (Ca), magnesium (Mg), and (PTH) at the time of birth, 24 hours afterwards in newborns after the mother has been treated with Mg-sulfate. We registered 86 term and preterm neonates (43 in each group) using simple census method delivered through vagina to preeclampsia pregnant women treated with Mg-sulfate immediately before birth in Khoramabad Asali Hospital, Iran. The first specimen was obtained from umbilical cord blood at birth, followed by the second sample of 2cc peripherally obtained from blood 24 hours after birth. The mean serum Mg level was higher than normal for both specimens in both term and preterm groups with no significant difference. The mean serum Ca level was higher in term group at both occasions, which turned out to be statistically significant (P<0.000) and (P=0.001) for the first and second specimens respectively. The mean PTH level was also in normal range for both groups at both times with no statistical significance. On the other hand, magnesium level showed a significant decline at 24 hours (P = 0.005) while PTH increased significantly (p<0.000) and (p=0.005) for term and preterm groups respectively. In contrast, Ca changes were not significantly different between the two specimens. Treatment with Mg-sulfate immediately before vaginal delivery increases Mg in both term and preterm neonates with no effect on Ca and PTH levels.

  12. Effectiveness of recovered magnesium phosphates as fertilizers in neutral and slightly alkaline soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Magnesium phosphates such as struvite (MgNH4PO4x6H2O) can be recovered from municipal, industrial and agricultural wastewaters. However, minimal research has been conducted on the beneficial reuse of these recovered products; conducted research has focused on low pH soils. This study determined wh...

  13. Nationwide data on municipal drinking water and hip fracture: could calcium and magnesium be protective? A NOREPOS study.

    PubMed

    Dahl, Cecilie; Søgaard, Anne Johanne; Tell, Grethe S; Flaten, Trond Peder; Hongve, Dag; Omsland, Tone Kristin; Holvik, Kristin; Meyer, Haakon E; Aamodt, Geir

    2013-11-01

    Norway has a high incidence of hip fractures, and the incidence varies by degree of urbanization. This variation may reflect a difference in underlying environmental factors, perhaps variations in the concentration of calcium and magnesium in municipal drinking water. A trace metal survey (1986-1991) in 556 waterworks (supplying 64% of the Norwegian population) was linked geographically to hip fractures from hospitals throughout the country (1994-2000). In all, 5472 men and 13,604 women aged 50-85years suffered a hip fracture. Poisson regression models were fitted, adjusting for age, urbanization degree, region of residence, type of water source, and pH. The concentrations of calcium and magnesium in drinking water were generally low. An inverse association was found between concentration of magnesium and risk of hip fracture in both genders (IRR men highest vs. lowest tertile=0.80, 95% CI: 0.74, 0.87; IRR women highest vs. lowest tertile=0.90, 95% CI: 0.85, 0.95), but no consistent association between calcium and hip fracture risk was observed. The highest tertile of urbanization degree (city), compared to the lowest (rural), was related to a 23 and 24% increase in hip fracture risk in men and women, respectively. The association between magnesium and hip fracture did not explain the variation in hip fracture risk between city and rural areas. Magnesium in drinking water may have a protective role against hip fractures; however this association should be further investigated.

  14. Theoretical investigation of the structures, stabilities, and NLO responses of calcium-doped pyridazine: alkaline-earth-based alkaline salt electrides.

    PubMed

    Wang, Yin-Feng; Huang, Jiangen; Jia, Li; Zhou, Guangpei

    2014-02-01

    Currently, whether alkaline-earth-doped compounds with electride characteristics are novel candidates for high-performance nonlinear optical (NLO) materials is unknown. In this paper, using quantum chemical computations, we show that: when doping calcium atoms into a family of alkaline-substituted pyridazines, alkaline-earth-based alkaline salt electrides M-H₃C₄N₂⋯Ca (M=H, Li, and K) with distended excess electron clouds are formed. Interestingly, from the triplet to the singlet state, the chemical valence of calcium atom changes from +1 to 0, and the dipole moment direction (μ₀) of the molecule reverses for each M-H₃C₄N₂⋯Ca. Changing pyridazine from without (H₄C₄N₂⋯Ca) to with one alkaline substituent (M-H₃C₄N₂⋯Ca, M=Li and K), the ground state changes from the triplet to the singlet state. The alkaline earth metal doping effect (electride effect) and alkaline salt effect on the static first hyperpolarizabilities (β₀) demonstrates that (1) the β₀ value is increased approximately 1371-fold from 2 (pyridazine, H₄C₄N₂) to 2745au (Ca-doped pyridazine, H₄C₄N₂⋯Ca), (2) the β₀ value is increased approximately 1146-fold from 2 in pyridazine (H₄C₄N₂) to 2294au in an Li-substituted pyridazine (Li-H₃C₄N₂), and (3) the β₀ value is increased 324-(M=Li) and 106-(M=K) fold from 826 (MLi) and 2294au (MK) to 268,679 (M=Li) and 245,878au (M=K), respectively, from the alkalized pyridazine (M-H₃C₄N₂) to the Ca-doped pyridazine (M-H₃C₄N₂⋯Ca). These results may provide a new means for designing high-performance NLO materials.

  15. [Comparative study of the urinary excretion of boron, calcium, magnesium and phosphorus in postmenopausal women with and without osteoporosis].

    PubMed

    José Ramón, Vielma; Mora Mora, Marylú; Marino Alarcón, Oscar; Hernández, Gladys; Josefina Linares, Ledy; Urdaneta Romero, Haideé; Arévalo González, Evelia

    2012-03-01

    In order to compare the possible relationship between urinary concentrations of boron, calcium, magnesium and phosphorus in serum and urine of postmenopausal women with and without osteoporosis, we selected 45 postmenopausal women over 47 years of age, divided into two groups: group I clinically healthy postmenopausal women and group II postmenopausal women with osteoporosis, without chronic kidney and hepatic diseases or diabetes mellitus. We determined the boron (B), phosphorus (P), total calcium (Ca) and total magnesium (Mg) in the urine of two hours, by atomic emission spectroscopy with induction-coupled plasma (ICPA-ES). Total calcium and total magnesium in serum were determined by atomic flame absorption spectroscopy (FAAS) and inorganic phosphorus in serum, and creatinine in serum and urine, by molecular absorption spectrometry. The preliminary results suggest the existence of a significant difference (p < 0.05) in boron and phosphorus concentrations in the urine of two hours between the groups. The model of linear regression analysis used showed a relationship between urinary concentrations of boron/creatinine index and calcium/ creatinine, magnesium/creatinine and phosphorus/creatinine indexes in the urine of postmenopausal women with osteoporosis.

  16. Effects of calcium and magnesium hardness on the fertilization and hatching success of channel X blue hybrid catfish eggs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aquifer used for hybrid catfish hatcheries is less than 10 mg/L of calcium hardness and 1- 25 mg/L of magnesium hardness. Embryonic development is deemed to be the most sensitive stage in the life cycle of a teleost. As egg development takes outside the fish’s body, water hardness is one abioti...

  17. Chronic dietary fiber supplementation with wheat dextrin does not inhibit calcium and magnesium absorption in premenopausal and postmenopausal women

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This placebo-controlled, randomized, crossover clinical study examined the effect of chronic wheat dextrin intake on calcium and magnesium absorption. Forty premenopausal and post menopausal women (mean +/- SD age 49.9 +/- 9.8 years)consumed wheat dextrin or placebo (15 g/day) for 2 weeks prior to 4...

  18. Influence of calcium, magnesium, or potassium ions on the formation and stability of emulsions prepared using highly hydrolyzed whey proteins.

    PubMed

    Ramkumar, C; Singh, H; Munro, P A; Singh, A M

    2000-05-01

    Oil-in-water emulsions (4 wt % soy oil) containing 4 wt % whey protein hydrolysate (WPH) (27% degree of hydrolysis) and different levels of calcium, magnesium, or potassium chloride were prepared in a two-stage homogenizer. Other emulsions containing 4 wt % WPH but including 0.35 wt % hydroxylated lecithin and different levels of the above minerals were similarly prepared. The formation and stability of these emulsions were determined by measuring oil droplet size distributions using laser light scattering and by confocal scanning laser microscopy and a gravity creaming test. Both lecithin-free and lecithin-containing emulsions showed no change in droplet size distributions with increasing concentration of potassium in the range 0-37.5 mM. In contrast, the diameter of emulsion droplets increased with increasing calcium or magnesium concentration >12.5 mM. Emulsions containing hydroxylated lecithin were more sensitive to the addition of calcium or magnesium than the lecithin-free emulsions. Storage of emulsions at 20 degrees C for 24 h further increased the diameter of droplets and resulted in extensive creaming in emulsions containing >25 mM calcium or magnesium. It appears that both flocculation and coalescence processes were involved in the destabilization of emulsions induced by the addition of divalent cations.

  19. STUDYING THE EFFECTS OF CALCIUM AND MAGNESIUM ON SIZE-DISTRIBUTED NITRATE AND AMMONIUM WITH EQUISOLV II. (R823186)

    EPA Science Inventory

    Abstract

    A chemical equilibrium code was improved and used to show that calcium and magnesium have a large yet different effect on the aerosol size distribution in different regions of Los Angeles. In the code, a new technique of solving individual equilibrium equation...

  20. Experimental and theoretical study of molecular structure of beryllium, magnesium, calcium, strontium and barium 4-nitrobenzoates.

    PubMed

    Samsonowicz, M; Regulska, E; Świsłocka, R; Lewandowski, W

    2013-02-15

    The influence of alkaline earth metal ions on the electronic system of 4-nitrobenzoic acid was studied in this paper. The vibrational (FT-IR) and NMR ((1)H and (13)C) spectra were recorded for 4-nitrobenzoic acid (4-nba) and its salts (4-nb). The assignment of vibrational spectra was done. Some shifts of band wavenumbers in alkaline earth metal 4-nitrobenzoates spectra were observed in the series from magnesium to barium salts. Good correlations between wavenumbers of the vibrational bands in the IR spectra of studied salts and ionic potential, electronegativity, inverse of atomic mass, ionic radius and ionization energy of studied metals were found. The regular changes in the chemical shifts of protons ((1)H NMR) and carbons ((13)C NMR) in the series of studied salts were also observed. Optimized geometrical structures of studied compounds were calculated by B3LYP method using 6-311++G(**) as well as LANL2DZ basis sets. Theoretical wavenumbers and intensities in IR and chemical shifts in NMR spectra were also obtained. The calculated parameters were compared with experimental data of studied compounds.

  1. Continental weathering following a Cryogenian glaciation: Evidence from calcium and magnesium isotopes

    NASA Astrophysics Data System (ADS)

    Kasemann, Simone A.; Pogge von Strandmann, Philip A. E.; Prave, Anthony R.; Fallick, Anthony E.; Elliott, Tim; Hoffmann, Karl-Heinz

    2014-06-01

    A marked ocean acidification event and elevated atmospheric carbon dioxide concentrations following the extreme environmental conditions of the younger Cryogenian glaciation have been inferred from boron isotope measurements. Calcium and magnesium isotope analyses offer additional insights into the processes occurring during this time. Data from Neoproterozoic sections in Namibia indicate that following the end of glaciation the continental weathering flux transitioned from being of mixed carbonate and silicate character to a silicate-dominated one. Combined with the effects of primary dolomite formation in the cap dolostones, this caused the ocean to depart from a state of acidification and return to higher pH after climatic amelioration. Differences in the magnitude of stratigraphic isotopic changes across the continental margin of the southern Congo craton shelf point to local influences modifying and amplifying the global signal, which need to be considered in order to avoid overestimation of the worldwide chemical weathering flux.

  2. [Concentrations of calcium, magnesium, sodium and potassium in human milk and infant formulas].

    PubMed

    Rodríguez Rodríguez, E M; Sanz Alaejos, M; Díaz Romero, C

    2002-12-01

    Concentrations of calcium, magnesium, sodium and potassium were determined in 55 samples of mature human milk from Canary women and 5 samples of powdered infant formula. According to the literature our data fell within the normal intervals described for each kind of milk. The mean concentration of Ca, Mg, Na y K of powdered infant formula was higher than those concentrations found in the human milks. Significant differences among the concentrations of Ca, Mg and Na for the milks of the considered mothers were observed. Only the Ca intakes for infants fed with human milk were lower than those requirements recommended by the Food and Nutrition Board (1989). However, the infants fed with powdered infant formula had an adequate intake of all the studied metals. A progressive decrease of the Na, K and Ca concentrations with the lactation stage was observed. Maternal age, parity and sex of the newborns did not affect the metal concentrations significantly.

  3. The final phases of calcium and magnesium phosphates precipitated from solutions of high to medium concentration

    NASA Astrophysics Data System (ADS)

    Abbona, Francesco; Lundager Madsen, Hans Erik; Boistelle, Roland

    1988-07-01

    The phases of calcium and magnesium phosphates, which are obtained by evolution at 25°C of the first precipitates in their mother solutions, are described in terms of pH and composition of solutions. The initial conditions were: 0.050M ≤ [P] ≤ 0.500M; [P] = [Ca] + [Mg]; 0 ≤ [Mg]/[Ca] ≤ 1. The most abundant final phases are brushite, CaHPO 4·2H 2O; monetite, CaHPO 4; newberyite, MgHPO 4·3H 2O and struvite, MgNH 4PO 4·6H 2O. At low concentration whitlockite, Ca 9MgH(PO 4) 7, occurs with the amorphous phase previously precipitated, Ca 3(PO 4) 2·nH 2O. The conditions for stability are discussed and the changes observed are interpreted.

  4. Calcium-magnesium Aluminosilicate (CMAS) Interactions with Advanced Environmental Barrier Coating Material

    NASA Technical Reports Server (NTRS)

    Wiesner, Valerie L.; Bansal, Narottam P.

    2015-01-01

    Particulates, like sand and volcanic ash, threaten the development of robust environmental barrier coatings (EBCs) that protect next-generation silicon-based ceramic matrix composite (CMC) turbine engine components from harsh combustion environments during service. The siliceous particulates transform into molten glassy deposits of calcium-magnesium aluminosilicate (CMAS) when ingested by an aircraft engine operating at temperatures above 1200C. In this study, a sample of desert sand was melted into CMAS glass to evaluate high-temperature interactions between the sand glass and an advanced EBC material. Desert sand glass was added to the surface of hot-pressed EBC substrates, which were then heated in air at temperatures ranging from 1200C to 1500C. Scanning electron microscopy and X-ray energy-dispersive spectroscopy were used to evaluate microstructure and phase compositions of specimens and the CMASEBC interface after heat treatments.

  5. 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.

  6. Magnesium and calcium isotopic characteristics of Tengchong volcanics: Recycling of marine carbonates into the SE Tibetan mantle

    NASA Astrophysics Data System (ADS)

    Liu, F.; Zhang, Z.; Liu, Y.; Zhu, H.; Kang, J.; Zhang, C.; Sun, W.; Wang, G. Q.

    2015-12-01

    Post-collisional high-K calc-alkaline volcanic rocks are widely distributed in Tengchong in the southeastern margin of Tibetan Plateau. Previous considerable petrological and Sr-Nd-Pb isotopic researches undoubtedly indicate that the mantle beneath Tengchong is heterogeneous and enriched. However, the genesis of such a kind of mantle is still poor understood and needs more constrains. One of the key points lead to the answer to this question is that, is there any recycled carbonate involved? Therefore, Magnesium and calcium isotopic compositions of mantle-derived volcanics should be investigated because they are good candidates to be potentially used to trace recycling of ancient marine carbonates into the mantle. In this study, we report high-precision Mg and Ca isotopic compositions for calc-alkaline volcanic rocks in Tengchong. These volcanic rocks show significantly lighter δ26Mg values (-0.44 to -0.36‰) than the mantle value (-0.25±0.07‰). Similarly, they display lighter δ44Ca values (0.65-0.80‰) than the mantle value (1.05±0.04‰). Because neither δ26Mg nor δ44Ca are correlated with SiO2 (50.8-61.6 wt.%) contents, and there is no relationships between δ26Mg or δ44Ca and typical trace element abundance ratios (e.g. Sm/Yb, Ba/Y), we conclude that magma differentiation or partial melting would lead to limited Mg and Ca isotopes fractionation. Thus, low δ26Mg and δ44Ca signatures of Tengchong volcanic rocks probably reflect that the δ26Mg and δ44Ca characteristics of the underneath mantle source, and are resulted from adding ancient marine carbonates into the primitive mantle which has low Mg and Ca isotopic compositions. Our model simulation using a two end-member mixing between Mg-Ca isotopic compositions of primitive mantle and ancient marine carbonate indicates that carbonates involved in the mantle source is mainly dolostone with minor limestone. Combined with the geotectonic evolution history in Tengchong, we propose that the enriched

  7. Calcium-induced folding and stabilization of the Pseudomonas aeruginosa alkaline protease.

    PubMed

    Zhang, Liang; Conway, James F; Thibodeau, Patrick H

    2012-02-03

    Pseudomonas aeruginosa is an opportunistic pathogen that contributes to the mortality of immunocompromised individuals and patients with cystic fibrosis. Pseudomonas infection presents clinical challenges due to its ability to form biofilms and modulate host-pathogen interactions through the secretion of virulence factors. The calcium-regulated alkaline protease (AP), a member of the repeats in toxin (RTX) family of proteins, is implicated in multiple modes of infection. A series of full-length and truncation mutants were purified for structural and functional studies to evaluate the role of Ca(2+) in AP folding and activation. We find that Ca(2+) binding induces RTX folding, which serves to chaperone the folding of the protease domain. Subsequent association of the RTX domain with an N-terminal α-helix stabilizes AP. These results provide a basis for the Ca(2+)-mediated regulation of AP and suggest mechanisms by which Ca(2+) regulates the RTX family of virulence factors.

  8. In vitro degradation and mechanical integrity of calcium-containing magnesium alloys in modified-simulated body fluid.

    PubMed

    Kannan, M Bobby; Raman, R K Singh

    2008-05-01

    The successful applications of magnesium-based alloys as degradable orthopaedic implants are mainly inhibited due to their high degradation rates in physiological environment and consequent loss in the mechanical integrity. This study examines the degradation behaviour and the mechanical integrity of calcium-containing magnesium alloys using electrochemical techniques and slow strain rate test (SSRT) method, respectively, in modified-simulated body fluid (m-SBF). Potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) results showed that calcium addition enhances the general and pitting corrosion resistances of magnesium alloys significantly. The corrosion current was significantly lower in AZ91Ca alloy than that in AZ91 alloy. Furthermore, AZ91Ca alloy exhibited a five-fold increase in the surface film resistance than AZ91 alloy. The SSRT results showed that the ultimate tensile strength and elongation to fracture of AZ91Ca alloy in m-SBF decreased only marginally (approximately 15% and 20%, respectively) in comparison with these properties in air. The fracture morphologies of the failed samples are discussed in the paper. The in vitro study suggests that calcium-containing magnesium alloys to be a promising candidate for their applications in degradable orthopaedic implants, and it is worthwhile to further investigate the in vivo corrosion behaviour of these alloys.

  9. Methods of use of calcium hexa aluminate refractory linings and/or chemical barriers in high alkali or alkaline environments

    DOEpatents

    McGowan, Kenneth A; Cullen, Robert M; Keiser, James R; Hemrick, James G; Meisner, Roberta A

    2013-10-22

    A method for improving the insulating character/and or penetration resistance of a liner in contact with at least one of an alkali and/or alkaline environments is provided. The method comprises lining a surface that is subject to wear by an alkali environment and/or an alkaline environment with a refractory composition comprising a refractory aggregate consisting essentially of a calcium hexa aluminate clinker having the formula CA.sub.6, wherein C is equal to calcium oxide, wherein A is equal to aluminum oxide, and wherein the hexa aluminate clinker has from zero to less than about fifty weight percent C.sub.12A.sub.7, and wherein greater than 98 weight percent of the calcium hexa aluminate clinker having a particle size ranging from -20 microns to +3 millimeters, for forming a liner of the surface. This method improves the insulating character/and or penetration resistance of the liner.

  10. CaSR-mediated interactions between calcium and magnesium homeostasis in mice

    PubMed Central

    Quinn, Stephen J.; Thomsen, Alex R. B.; Egbuna, Ogo; Pang, Jian; Baxi, Khanjan; Goltzman, David; Pollak, Martin

    2013-01-01

    Calcium (Ca) and magnesium (Mg) homeostasis are interrelated and share common regulatory hormones, including parathyroid hormone (PTH) and vitamin D. However, the role of the calcium-sensing receptor (CaSR) in Mg homeostasis in vivo is not well understood. We sought to investigate the interactions between Mg and Ca homeostasis using genetic mouse models with targeted inactivation of PTH (PTH KO) or both PTH and the calcium-sensing receptor (CaSR) (double knockout, DKO). Serum Mg is lower in PTH KO and DKO mice than in WT mice on standard chow, whereas supplemental dietary Ca leads to equivalent Mg levels for all three genotypes. Mg loading increases serum Mg in all genotypes; however, the increase in serum Mg is most pronounced in the DKO mice. Serum Ca is increased with Mg loading in the PTH KO and DKO mice but not in the WT mice. Here, too, the hypercalcemia is much greater in the DKO mice. Serum and especially urinary phosphate are reduced during Mg loading, which is likely due to intestinal chelation of phosphate by Mg. Mg loading decreases serum PTH in WT mice and increases serum calcitonin in both WT and PTH KO mice but not DKO mice. Furthermore, Mg loading elevates serum 1,25-dihydroxyvitamin D in all genotypes, with greater effects in PTH KO and DKO mice, possibly due to reduced levels of serum phosphorus and FGF23. These hormonal responses to Mg loading and the CaSR's role in regulating renal function may help to explain changes in serum Mg and Ca found during Mg loading. PMID:23360827

  11. Maxillary sinus floor elevation using a tissue-engineered bone with calcium-magnesium phosphate cement and bone marrow stromal cells in rabbits.

    PubMed

    Zeng, Deliang; Xia, Lunguo; Zhang, Wenjie; Huang, Hui; Wei, Bin; Huang, Qingfeng; Wei, Jie; Liu, Changsheng; Jiang, Xinquan

    2012-04-01

    The objective of this study was to assess the effects of maxillary sinus floor elevation with a tissue-engineered bone constructed with bone marrow stromal cells (bMSCs) and calcium-magnesium phosphate cement (CMPC) material. The calcium (Ca), magnesium (Mg), and phosphorus (P) ions released from calcium phosphate cement (CPC), magnesium phosphate cement (MPC), and CMPC were detected by inductively coupled plasma atomic emission spectroscopy (ICP-AES), and the proliferation and osteogenic differentiation of bMSCs seeded on CPC, MPC, and CMPC or cultured in CPC, MPC, and CMPC extracts were measured by MTT analysis, alkaline phosphatase (ALP) activity assay, alizarin red mineralization assay, and real-time PCR analysis of the osteogenic genes ALP and osteocalcin (OCN). Finally, bMSCs were combined with CPC, MPC, and CMPC and used for maxillary sinus floor elevation in rabbits, while CPC, MPC, or CMPC without cells served as control groups. The new bone formation in each group was detected by histological finding and fluorochrome labeling at weeks 2 and 8 after surgical operation. It was observed that the Ca ion concentrations of the CMPC and CPC scaffolds was significantly higher than that of the MPC scaffold, while the Mg ions concentration of CMPC and MPC was significantly higher than that of CPC. The bMSCs seeded on CMPC and MPC or cultured in their extracts proliferated more quickly than the cells seeded on CPC or cultured in its extract, respectively. The osteogenic differentiation of bMSCs seeded on CMPC and CPC or cultured in the corresponding extracts was significantly enhanced compared to that of bMSCs seeded on MPC or cultured in its extract; however, there was no significant difference between CMPC and CPC. As for maxillary sinus floor elevation in vivo, CMPC could promote more new bone formation and mineralization compared to CPC and MPC, while the addition of bMSCs could further enhance its new bone formation ability significantly. Our data suggest that

  12. Magnesium hydrogen carbonate natural mineral water enriched with K(+)-citrate and vitamin B6 improves urinary abnormalities in patients with calcium oxalate nephrolithiasis.

    PubMed

    Bren, A; Kmetec, A; Kveder, R; Kaplan-Pavlovcic, S

    1998-01-01

    The influence of drinking magnesium hydrogen carbonate natural mineral water enriched with potassium citrate on urinary metabolic abnormalities was prospectively studied in 27 patients with recurrent calcium oxalate nephrolithiasis. The mean 24-hour urinary pH shifted from 6.34 to 6.93 (p < 0.01), the mean urinary magnesium/urinary creatinine ratio rose from 0.47 to 0.67 (p < 0.01), the mean urinary citrate/urinary creatinine ratio increased from 0.26 to 0.35 (p NS), and the mean 24-hour urinary calcium decreased from 7.98 to 6.05 mmol (p < 0.05). The effects of magnesium hydrogen carbonate natural mineral water enriched with potassium citrate were found to be favorable on urinary calcium, urinary magnesium/urinary creatinine ratio and urinary pH in patients with calcium oxalate nephrolithiasis.

  13. The Effects of Alkaline pH on Microleakage of Mineral Trioxide Aggregate and Calcium Enriched Mixture Apical Plugs

    PubMed Central

    Mirhadi, Hossein; Moazzami, Fariborz; Rangani Jahromi, Saeed; Safarzade, Sareh

    2016-01-01

    Statement of the Problem Alkaline pH can affect the physical and chemical properties and sealing ability of apical plug material. Calcium hydroxide is used as an intracanal medication to complete disinfection of root canals. It raises the pH of environment to alkaline value. Purpose The aim of this in vitro study was to evaluate and compare the effect of alkaline pH on the sealing ability of calcium-enriched mixture (CEM) cement and mineral trioxide aggregate (MTA) apical plugs. Materials and Method Seventy single-rooted human maxillary anterior teeth were randomly divided to two experimental groups for Angelus MTA and CEM cement (n=30) and two control groups (n=5). Each group was divided into two subgroups of 15 for neutral and alkaline pH, and 1 negative and 1 positive control groups of 5. The root canals were cleaned and shaped by using ProTaper rotary system (Dentsply Maillefer; Ballaigues, Switzerland) and the terminal 3mm of the roots were resected. Then, MTA and CEM cement were condensed in apical region with 3mm thickness. The samples were exposed to two environments with different pH values of 13 and 7.4. The leakage was assessed by using the fluid filtration technique at 1, 7, 14, 30 days intervals. Data were analyzed by the repeated measures MANOVA. Results There was no statistically significant difference in the rate of microleakage between neutral and alkaline pH of CEM cement and MTA (p> 0.05). The sealing ability of MTA in an alkaline pH of 13 was significantly less than CEM cement in this pH (p< 0.05). Conclusion An environment with alkaline pH had no adverse effect on the sealing ability of MTA and CEM cement used as apical plugs. CEM cement had better sealing ability in alkaline pH. PMID:26966703

  14. Effect of Spirulina maxima Supplementation on Calcium, Magnesium, Iron, and Zinc Status in Obese Patients with Treated Hypertension.

    PubMed

    Suliburska, J; Szulińska, M; Tinkov, A A; Bogdański, P

    2016-09-01

    The effects of Spirulina maxima supplementation on calcium, magnesium, iron, and zinc status were studied in a double-blind placebo-controlled trial of 50 obese subjects with treated hypertension, each randomized to receive 2 g of spirulina or a placebo daily for 3 months. At baseline and after treatment, the calcium, magnesium, iron, and zinc concentration in plasma was assessed. It was found that 3 months of S. maxima supplementation resulted in a significant decrease in the iron level in the plasma of obese patients. In conclusion, this is the first clinical study on the influence of spirulina supplementation on mineral status in obese patients with hypertension. Spirulina supplementation affects the iron status of obese Caucasians with well-treated hypertension.

  15. Inhibition of beta-amylase activity by calcium, magnesium and zinc ions determined by spectrophotometry and isothermal titration calorimetry.

    PubMed

    Dahot, M Umar; Saboury, A A; Moosavi-Movahedi, A A

    2004-04-01

    The inhibition effect of metal ions on beta amylase activity was studied. The inhibitor-binding constant (Ki) was determined by spectrophotometric and isothermal titration calorimetric (ITC) methods. The binding of calcium, magnesium and zinc ion as inhibitors at the active site of barley beta amylase was studied at pH = 4.8 (sodium acetate 16 mM) and T = 300K. The Ki and enthalpy of binding for calcium (13.4, 13.1 mM and -14.3 kJ/mol), magnesium (18.6, 17.8mM and -17.7 kJ/mol) and zinc (17.5, 17.7 mM and -20.0 kJ/mol) were found by spectrophotometric and ITC methods respectively.

  16. Influence of ethanol content in the precipitation medium on the composition, structure and reactivity of magnesium-calcium phosphate.

    PubMed

    Babaie, Elham; Zhou, Huan; Lin, Boren; Bhaduri, Sarit B

    2015-08-01

    Biocompatible amorphous magnesium calcium phosphate (AMCP) particles were synthesized using ethanol in precipitation medium from moderately supersaturated solution at pH10. Some synthesis parameters such as, (Mg+Ca):P, Mg:Ca ratio and different drying methods on the structure and stability of as-produced powder was studied and characterized using SEM, XRD and cell cytocompatibility. The results showed that depending on the Mg(2+) concentration, nano crystalline Struvite (MgNH4PO4·6H2O) can also be alternatively formed. However, the as-formed AMCP preserved its amorphous structure after 7 days of incubation in SBF for tested phosphate concentration, and equally ionic concentration of magnesium and calcium.

  17. Phase III Randomized, Placebo-Controlled, Double-Blind Study of Intravenous Calcium and Magnesium to Prevent Oxaliplatin-Induced Sensory Neurotoxicity (N08CB/Alliance)

    PubMed Central

    Loprinzi, Charles L.; Qin, Rui; Dakhil, Shaker R.; Fehrenbacher, Louis; Flynn, Kathleen A.; Atherton, Pamela; Seisler, Drew; Qamar, Rubina; Lewis, Grant C.; Grothey, Axel

    2014-01-01

    Purpose Cumulative neurotoxicity is a prominent toxicity of oxaliplatin-based therapy. Intravenous calcium and magnesium have been extensively used to reduce oxaliplatin-induced neurotoxicity. This trial was designed to definitively test whether calcium/magnesium decreases oxaliplatin-related neurotoxicity. Patients and Methods In all, 353 patients with colon cancer undergoing adjuvant therapy with FOLFOX (fluorouracil, leucovorin, and oxaliplatin) were randomly assigned to intravenous calcium/magnesium before and after oxaliplatin, a placebo before and after, or calcium/magnesium before and placebo after. The primary end point was cumulative neurotoxicity measured by the sensory scale of the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Chemotherapy-Induced Peripheral Neuropathy 20 tool. Results There were no statistically significant neuropathy differences among the study arms as measured by the primary end point or additional measures of neuropathy, including clinician-determined measurement of the time to grade 2 neuropathy by using the National Cancer Institute Common Terminology Criteria for Adverse Events scale or an oxaliplatin-specific neuropathy scale. In addition, calcium/magnesium did not substantially decrease oxaliplatin-induced acute neuropathy. Conclusion This study does not support using calcium/magnesium to protect against oxaliplatin-induced neurotoxicity. PMID:24297951

  18. Analysis of the effects of calcium or magnesium on voltage-clamp currents in perfused squid axons bathed in solutions of high potassium.

    PubMed

    Rojas, E; Taylor, R E; Atwater, I; Bezanilla, F

    1969-10-01

    Isolated axons from the squid, Dosidicus gigas, were internally perfused with potassium fluoride solutions. Membrane currents were measured following step changes of membrane potential in a voltage-clamp arrangement with external isosmotic solution changes in the order: potassium-free artificial seawater; potassium chloride; potassium chloride containing 10, 25, 40 or 50, mM calcium or magnesium; and potassium-free artificial seawater. The following results suggest that the currents measured under voltage clamp with potassium outside and inside can be separated into two components and that one of them, the predominant one, is carried through the potassium system. (a) Outward currents in isosmotic potassium were strongly and reversibly reduced by tetraethylammonium chloride. (b) Without calcium or magnesium a progressive increase in the nontime-dependent component of the currents (leakage) occurred. (c) The restoration of calcium or magnesium within 15-30 min decreases this leakage. (d) With 50 mM divalent ions the steady-state current-voltage curve was nonlinear with negative resistance as observed in intact axons in isosmotic potassium. (e) The time-dependent components of the membrane currents were not clearly affected by calcium or magnesium. These results show a strong dependence of the leakage currents on external calcium or magnesium concentration but provide no support for the involvement of calcium or magnesium in the kinetics of the potassium system.

  19. Assessment of salivary calcium, phosphate, magnesium, pH, and flow rate in healthy subjects, periodontitis, and dental caries

    PubMed Central

    Rajesh, K. S.; Zareena; Hegde, Shashikanth; Arun Kumar, M. S.

    2015-01-01

    Aim: This study was conducted to estimate and compare inorganic salivary calcium, phosphate, magnesium, salivary flow rate, and pH of unstimulated saliva and oral hygiene status of healthy subjects, subjects with periodontitis and dental caries, and to correlate salivary calcium level with number of intact teeth. Materials and Methods: The study population consisted of 48 systemically healthy subjects in the age group of 18-55 years, which was further divided into three groups: healthy, periodontitis, and dental caries. Oral hygiene index-simplified, probing pocket depth, clinical attachment level, the number of intact teeth, and active carious lesions were recorded. Estimation of inorganic salivary calcium, phosphate, and magnesium was performed spectrophotometrically using Vitros 5.1 FS. Statistical analysis was performed using the one-way analysis of variance test at 5% significance level. Results: There was a statistically significant increase in inorganic salivary calcium, phosphate, pH, flow rate, and poor oral hygiene status in periodontitis group compared to dental caries and healthy group. Conclusion: Subjects with increased inorganic salivary calcium, phosphate, pH, flow rate, and poor oral hygiene are at a higher risk of developing periodontitis. Since there is increased remineralization potential, these subjects have more number of intact teeth compared to the dental caries group. PMID:26681848

  20. Magnesium modulates parathyroid hormone secretion and upregulates parathyroid receptor expression at moderately low calcium concentration

    PubMed Central

    Rodríguez-Ortiz, Maria E.; Canalejo, Antonio; Herencia, Carmen; Martínez-Moreno, Julio M.; Peralta-Ramírez, Alan; Perez-Martinez, Pablo; Navarro-González, Juan F.; Rodríguez, Mariano; Peter, Mirjam; Gundlach, Kristina; Steppan, Sonja; Passlick-Deetjen, Jutta; Muñoz-Castañeda, Juan R.; Almaden, Yolanda

    2014-01-01

    Background The interest on magnesium (Mg) has grown since clinical studies have shown the efficacy of Mg-containing phosphate binders. However, some concern has arisen for the potential effect of increased serum Mg on parathyroid hormone (PTH) secretion. Our objective was to evaluate the direct effect of Mg in the regulation of the parathyroid function; specifically, PTH secretion and the expression of parathyroid cell receptors: CaR, the vitamin D receptor (VDR) and FGFR1/Klotho. Methods The work was performed in vitro by incubating intact rat parathyroid glands in different calcium (Ca) and Mg concentrations. Results Increasing Mg concentrations from 0.5 to 2 mM produced a left shift of PTH–Ca curves. With Mg 5 mM, the secretory response was practically abolished. Mg was able to reduce PTH only if parathyroid glands were exposed to moderately low Ca concentrations; with normal–high Ca concentrations, the effect of Mg on PTH inhibition was minor or absent. After 6-h incubation at a Ca concentration of 1.0 mM, the expression of parathyroid CaR, VDR, FGFR1 and Klotho (at mRNA and protein levels) was increased with a Mg concentration of 2.0 when compared with 0.5 mM. Conclusions Mg reduces PTH secretion mainly when a moderate low calcium concentration is present; Mg also modulates parathyroid glands function through upregulation of the key cellular receptors CaR, VDR and FGF23/Klotho system. PMID:24103811

  1. Improved osteogenesis and angiogenesis of magnesium-doped calcium phosphate cement via macrophage immunomodulation.

    PubMed

    Wang, Meng; Yu, Yuanman; Dai, Kai; Ma, Zhengyu; Liu, Yang; Wang, Jing; Liu, Changsheng

    2016-10-18

    Immune responses are vital for bone regeneration and play an essential role in the fate of biomaterials after implantation. As a kind of plastic cell, macrophages are central regulators of the immune response during the infection and wound healing process including osteogenesis and angiogenesis. Magnesium-calcium phosphate cement (MCPC) has been reported as a promising candidate for bone repair with promoted osteogenesis both in vitro and in vivo. However, relatively little is known about the effects of MCPC on immune response and the following outcome. In this study, we investigated the interactions between macrophages and MCPC. Here we found that the pro-inflammatory cytokines including TNF-α and IL-6 were less expressed and the bone repair related cytokine of TGF-β1 was up-regulated by macrophages in MCPC extract. Furthermore, the enhanced osteogenic capacity of BMSCs and angiogenic potential of HUVECs were acquired in vitro by the MCPC-induced immune microenvironment. These findings suggest that MCPC is able to facilitate bone healing by endowing favorable osteoimmunomodulatory properties and influencing crosstalk behavior between immune cells and osteogenesis-related cells.

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

    NASA Technical Reports Server (NTRS)

    Ahlborg, Nadia L.; Zhu, Dongming

    2013-01-01

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

  3. 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

  4. Chemical and mechanical consequences of environmental barrier coating exposure to calcium-magnesium-aluminosilicate.

    SciTech Connect

    Harder, B.; Ramirez-Rico, J.; Almer, J. D.; Kang, L.; Faber, K.

    2011-06-01

    The success of Si-based ceramics as high-temperature structural materials for gas turbine applications relies on the use of environmental barrier coatings (EBCs) with low silica activity, such as Ba{sub 1-x}Sr{sub x}Al{sub 2}Si{sub 2}O{sub 8} (BSAS), which protect the underlying components from oxidation and corrosion in combustion environments containing water vapor. One of the current challenges concerning EBC lifetime is the effect of sandy deposits of calcium-magnesium-aluminosilicate (CMAS) glass that melt during engine operation and react with the EBC, changing both its composition and stress state. In this work, we study the effect of CMAS exposure at 1300 C on the residual stress state and composition in BSAS-mullite-Si-SiC multilayers. Residual stresses were measured in BSAS multilayers exposed to CMAS for different times using high-energy X-ray diffraction. Their microstructure was studied using a combination of scanning electron microscopy and transmission electron microscopy techniques. Our results show that CMAS dissolves the BSAS topcoat preferentially through the grain boundaries, dislodging the grains and changing the residual stress state in the topcoat to a nonuniform and increasingly compressive stress state with increasing exposure time. The presence of CMAS accelerates the hexacelsian-to-celsian phase transformation kinetics in BSAS, which reacts with the glass by a solution-reprecipitation mechanism. Precipitates have crystallographic structures consistent with Ca-doped celsian and Ba-doped anorthite.

  5. Calcium, copper, iron, magnesium, silicon and zinc content of hair in Parkinson's disease.

    PubMed

    Forte, Giovanni; Alimonti, Alessandro; Violante, Nicola; Di Gregorio, Marco; Senofonte, Oreste; Petrucci, Francesco; Sancesario, Giuseppe; Bocca, Beatrice

    2005-01-01

    The aetiology of Parkinson's disease (PD) is still unknown, but some hypotheses have focused on the imbalances in body levels of metals as co-factors of risk. To assess whether hair could be a reliable marker of possible changes, calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), silicon (Si) and zinc (Zn) were determined in hair from 81 patients affected by PD and 17 age-matched controls. Care was taken to eliminate external contamination of the hair by thorough washing. Digestion of the matrix was achieved by an acid-assisted microwave procedure. Quantification of the elements was performed by inductively coupled plasma atomic emission spectrometry. Results indicated significantly lower levels of Fe in the hair of patients (p=0.018) compared with controls. Ca and Mg levels were slightly lower while Zn levels were higher in patients, although these differences were not significant; neither were variations in Cu and Si. Ca and Mg were at least 1.5 times higher in females than in males in both controls and patients. In addition, Ca correlated positively with Mg in both groups and in both sexes (p-value always less than 0.03), and negatively with age in patients (p<0.01). Finally, element levels did not correlate with either the duration or the severity of the disease or with anti-Parkinson treatment.

  6. Association of dietary calcium, phosphorus, and magnesium intake with caries status among schoolchildren.

    PubMed

    Lin, Han-Shan; Lin, Jia-Rong; Hu, Suh-Woan; Kuo, Hsiao-Ching; Yang, Yi-Hsin

    2014-04-01

    The aim of this study was to investigate the associations between caries experience and daily intake of calcium (Ca), phosphorus (P), magnesium (Mg), and Ca/P ratio. A total of 2248 schoolchildren were recruited based on a population-based survey. Each participant received a dental examination and questionnaire interviews about the 24-hour dietary recalls and food frequency. The daily intake of Ca, P, Mg, and Ca/P ratio were inversely associated with primary caries index, but only the Ca/P ratio remained significant after adjusting for potential confounders. According to the Taiwanese Dietary Reference Intakes, the Ca/P ratio was related to both caries in primary teeth (odds ratio = 0.52, p = 0.02) and in permanent teeth (odds ratio = 0.59, p = 0.02). The daily intakes of Ca/P ratio remained an important factor for caries after considering potential confounding factors.

  7. Calcium and magnesium in drinking-water and risk of death from lung cancer in women.

    PubMed

    Cheng, Meng-Hsuan; Chiu, Hui-Fen; Tsai, Shang-Shyue; Chen, Chih-Cheng; Yang, Chun-Yuh

    2012-01-01

    The possible association between the risk of lung cancer in women and the levels of calcium (Ca) and magnesium (Mg) in drinking-water from municipal supplies was investigated in a matched, case-control study in Taiwan. All eligible female lung cancer deaths (3,532 cases) of Taiwan residents, from 2000 through to 2008, were compared with deaths from other causes (3,532 controls), and the levels of Ca and Mg in drinking-water of these residents were determined. Data on Ca and Mg levels in drinking-water throughout Taiwan were obtained from the Taiwan Water Supply Corporation (TWSC). The control group consisted of people who died from other causes, and the controls were pair-matched to the cases by sex, year of birth, and year of death. The adjusted odd ratios were not statistically significant for the relationship between Ca levels in drinking-water and lung cancer in women. The adjusted odd ratios for female lung cancer deaths for those with higher Mg levels in their drinking-water, as compared to the lowest tertile, were 0.82 (95% CI = 0.72-0.93) and 0.80 (95% CI = 0.69-0.93), respectively. The results of the present study show that there is a significant trend toward a decreased risk of lung cancer in women with increasing Mg levels in drinking-water.

  8. Simultaneously detection of calcium and magnesium in various samples by calmagite and chemometrics data processing

    NASA Astrophysics Data System (ADS)

    Rasouli, Zolaikha; Ghavami, Raouf

    2016-12-01

    The current study describes results of the application of radial basis function-partial least squares (RBF-PLS), partial robust M-regression (PRM), singular value decomposition (SVD), evolving factor analysis (EFA), multivariate curve resolution with alternating least squares (MCR-ALS) and rank annihilation factor analysis (RAFA) methods for the purposes of simultaneous determination of trace amounts calcium (Ca2 +) and magnesium (Mg2 +) and exploratory analysis based on their colored complexes formation with 1-(1-hydroxy-4-methyl-2-phenylazo)-2-naphthol-4-sulfonic acid (calmagite) as chromomeric reagent. The complex formation Ca2 + and Mg2 + with calmagite was investigated under pH 10.20. The performance of RBF-PLS model in detection of minerals was compared with PRM as a linear model. The pure concentration and spectral profiles were obtained using MCR-ALS. EFA and SVD were used to distinguish the number species. The stability constants of the complexes were derived using RAFA. Finally, RBF-PLS was utilized for simultaneous determination of minerals in pharmaceutical formulation and various vegetable samples.

  9. 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...

  10. 40 CFR 721.2076 - D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 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...

  11. Aquatic toxicity of magnesium sulfate, and the influence of calcium, in very low ionic concentration water.

    PubMed

    van Dam, Rick A; Hogan, Alicia C; McCullough, Clint D; Houston, Melanie A; Humphrey, Chris L; Harford, Andrew J

    2010-02-01

    The toxicity of magnesium sulfate (MgSO(4)), and the influence of calcium (Ca), were assessed in very soft freshwater (natural Magela Creek water [NMCW]) using six freshwater species (Chlorella sp., Lemna aequinoctialis, Amerianna cumingi, Moinodaphnia macleayi, Hydra viridissima, and Mogurnda mogurnda). The study involved five stages: toxicity of MgSO(4) in NMCW, determination of the toxic ion, influence of Ca on Mg toxicity, toxicity of MgSO(4) at an Mg:Ca mass ratio of 9:1, and derivation of water quality guideline values for Mg. The toxicity of MgSO(4) was higher than previously reported, with chronic median inhibition concentration (IC50)/acute median lethal concentration (LC50) values ranging from 4 to 1,215 mg/L, as Mg. Experiments exposing the 3 most sensitive species (L. aequinoctialis, H. viridissima, and A. cumingi) to Na(2)SO(4) and MgCl(2) confirmed that Mg was the toxic ion. Additionally, Ca was shown to have an ameliorative effect on Mg toxicity. For L. aequinoctialis and H. viridissima, Mg toxicity at the IC50 concentration was eliminated at Mg:Ca (mass) ratios of < or =10:1 and < or =9:1, respectively. For A. cumingi, a 10 to 30% effect persisted at the IC50 concentration at Mg:Ca ratios <9:1. The toxicity of MgSO(4) in NMCW at a constant Mg:Ca ratio of 9:1 was lower than at background Ca, with chronic IC50/acute LC50 values from 96 to 4,054 mg/L, as Mg. Water quality guideline values for Mg (to protect 99% of species) at Mg:Ca mass ratios of >9:1 and < or =9:1 were 0.8 and 2.5 mg/L, respectively. Magnesium can be toxic at concentrations approaching natural background levels, but toxicity is dependent on Ca concentrations, with exposure in very low ionic concentration, Ca-deficient waters posing the greatest risk to aquatic life.

  12. Chelatometric determination of calcium and magnesium in iron ores, slags, anorthosite, limestone, copper-nickel-lead-zinc ores and divers materials.

    PubMed

    Hitchen, A; Zechanowitsch, G

    1980-03-01

    Chelatometric methods for the determination of calcium and magnesium in iron ores, slags, anorthosite, copper-nickel-lead-zinc ores and various other materials are described. Potential interfering elements are masked with triethanolamine and potassium cyanide. In one aliquot calcium is titrated at pH > 12, with calcein and thymolphthalein mixed indicator and in another aliquot calcium and magnesium are titrated in ammonia buffer, with o-cresolphthalein complexone screened with Naphthol Green B as indicator. The results compare favourably with certified values for reference materials of diverse nature.

  13. Basalt as a solid source of calcium and alkalinity for the sequestration of carbon dioxide in building materials

    NASA Astrophysics Data System (ADS)

    Johnson, N. C.; Westfield, I.; Lu, P.; Bourcier, W. L.; Kendall, T.; Constantz, B. R.

    2010-12-01

    Motivated by the idea of converting waste carbon dioxide into usable building products, Calera Corporation has developed a multi-step process that sequesters CO2 as carbonate minerals in cementitious materials. Process inputs include dissolved divalent cations and alkalinity, both of which can be extracted from basalt. In one mode of the Calera process, the electrochemical production of alkalinity generates large volumes of hydrochloric acid as a by-product, which has been shown to effectively leach divalent cations from basalt while being neutralized by the basalt dissolution reaction. Using a 10:1 1M HCl solution to rock ratio, 3500 ppm Ca was extracted while the initial solution was neutralized to a pH of 2.60 in two weeks at a temperature of 80oC in an anoxic batch reactor. In this scenario, mineral carbonation occurs via three steps: electrochemical production of alkalinity, CO2 absorption by the alkaline stream, then precipitation by mixing the basalt-derived divalent cation stream and the CO2-containing alkaline stream. In a second scenario, alkalinity is extracted from basalt using an alkalinity capacitor, a weak acid. This solution may contain a proton source, such as ammonium chloride, or a hydroxyl acceptor, such as boric acid, but the main design constraint is that the pKa of the capacitor be high enough to deprontonate carbonic acid. The weak acid solution is mixed with basalt in an anoxic batch reactor and the dissolving rock consumes protons from the weak acid, generating the conjugate base. The solution rich in conjugate base then absorbs CO2 and the carbonate-rich solution is mixed with a calcium-rich stream to precipitate carbonate minerals. We have extracted up to 1100 mmol alkalinity per kg rock using an alkalinity capacitor, versus no more than 50 mmol alkalinity per kg rock using DI water as a solvent. Again, carbon sequestration occurs via three steps: alkalinity extraction from basalt, CO2 absorption, and finally carbonate precipitation

  14. Carboxylated molecules regulate magnesium content of amorphous calcium carbonates during calcification

    PubMed Central

    Wang, Dongbo; Wallace, Adam F.; De Yoreo, James J.; Dove, Patricia M.

    2009-01-01

    With the realization that many calcified skeletons form by processes involving a precursor phase of amorphous calcium carbonate (ACC), a new paradigm for mineralization is emerging. There is evidence the Mg content in biogenic ACC is regulated by carboxylated (acidic) proteins and other macromolecules, but the physical basis for such a process is unknown. We test the hypothesis that ACC compositions express a systematic relationship to the chemistry of carboxyl-rich biomolecules. A series of inorganic control experiments were conducted to establish the dependence of Mg/Ca ratios in ACC on solution composition. We then determined the influence of a suite of simple carboxylated organic acids on Mg content. Molecules with a strong affinity for binding Ca compared with Mg promote the formation of Mg-enriched ACC that is compositionally equivalent to high-magnesium calcites and dolomite. Measurements show Mg/Ca ratios are controlled by a predictable dependence upon the binding properties of the organic molecules. The trend appears rooted in the conformation and electrostatic potential topology of each molecule, but dynamic factors also may be involved. The dependence suggests a physical basis for reports that specific sequences of calcifying proteins are critical to modulating mineralization. Insights from this study may provide a plausible explanation for why some biogenic carbonates and carbonaceous cements often contain higher Mg signatures than those that are possible by classical crystal growth processes. The findings reiterate the controls of microenvironment on mineralization and suggest an origin of compositional offsets, or vital effects, long recognized by the paleoclimate community. PMID:19955417

  15. Are cyclopentadienylberyllium, magnesium and calcium hydrides carbon or metal acids in the gas phase?

    PubMed

    Hurtado, Marcela; Lamsabhi, Al-Mokhtar; Mó, Otilia; Yáñez, Manuel; Guillemin, Jean-Claude

    2010-05-21

    The structure and bonding of cyclopentadienylberyllium (CpBeH), magnesium (CpMgH), and calcium (CpCaH) hydrides as well as those of their deprotonated species have been investigated by means of B3LYP/6-311+G(3df,2p)//B3LYP/6-311+G(d,p) and B3LYP/6-311+G(3df,2p)//QCISD/6-311+G(d,p) density functional theory (DFT) calculations. The three compounds exhibit C(5v) equilibrium conformations in their ground states. For CpBeH the agreement between the calculated geometry and that determined by MW spectroscopy is excellent. CpMgH and CpCaH can be viewed almost as the result of the interaction between a C₅H₅⁻ anion and a XH(+) (X = Mg, Ca) cation. Conversely, for CpBeH the interaction between the C₅H₅ and the BeH subunits is significantly covalent. These compounds exhibit a significant aromaticity, usually named three-dimension aromaticity, in contrast with the unsubstituted cyclopentadiene compound. The CpBeH derivative behaves as a C acid in the gas phase and is less acidic than cyclopentadiene. More importantly, CpMgH and CpCaH, in spite of the X(+δ)H(-δ) polarity exhibited by the X-H bond in the neutral systems, are predicted to be metal acids in the gas phase. Also surprisingly, both the Mg and the Ca derivatives are stronger acids than the Be analogue, and only slightly weaker acids than cyclopentadiene. This somewhat unexpected result is the consequence of two concomitant facts: the lower dissociation energy of the X-H (X = Mg, Ca) bonds with respect to the C-H bonds, and the significantly high electron affinity of the C₅H₅X* (X = Mg, Ca) radicals.

  16. Determination of calcium, magnesium and zinc in lubricating oils by flame atomic absorption spectrometry using a three-component solution.

    PubMed

    Zmozinski, Ariane V; de Jesus, Alexandre; Vale, Maria G R; Silva, Márcia M

    2010-12-15

    Lubricating oils are used to decrease wear and friction of movable parts of engines and turbines, being in that way essential for the performance and the increase of that equipment lifespan. The presence of some metals shows the addition of specific additives such as detergents, dispersals and antioxidants that improve the performance of these lubricants. In this work, a method for determination of calcium, magnesium and zinc in lubricating oil by flame atomic absorption spectrometry (F AAS) was developed. The samples were diluted with a small quantity of aviation kerosene (AVK), n-propanol and water to form a three-component solution before its introduction in the F AAS. Aqueous inorganic standards diluted in the same way have been used for calibration. To assess the accuracy of the new method, it was compared with ABNT NBR 14066 standard method, which consists in diluting the sample with AVK and in quantification by F AAS. Two other validating methods have also been used: the acid digestion and the certified reference material NIST (SRM 1084a). The proposed method provides the following advantages in relation to the standard method: significant reduction of the use of AVK, higher stability of the analytes in the medium and application of aqueous inorganic standards for calibration. The limits of detection for calcium, magnesium and zinc were 1.3 μg g(-1), 0.052 μg g(-1) and 0.41 μg g(-1), respectively. Concentrations of calcium, magnesium and zinc in six different samples obtained by the developed method did not differ significantly from the results obtained by the reference methods at the 95% confidence level (Student's t-test and ANOVA). Therefore, the proposed method becomes an efficient alternative for determination of metals in lubricating oil.

  17. Biocompatibility of fluoride-coated magnesium-calcium alloys with optimized degradation kinetics in a subcutaneous mouse model.

    PubMed

    Drynda, Andreas; Seibt, Juliane; Hassel, Thomas; Bach, Friedrich Wilhelm; Peuster, Matthias

    2013-01-01

    The principle of biodegradation has been considered for many years in the development of cardiovascular stents, especially for patients with congenital heart defects. A variety of materials have been examined with regard to their suitability for cardiovascular devices. Iron- and magnesium-based stents were investigated intensively during the last years. It has been shown, that iron, or iron based alloys have slow degradation kinetics whereas magnesium-based systems exhibit rapid degradation rates. Recently we have developed fluoride coated binary magnesium-calcium alloys with reduced degradation kinetics. These alloys exhibit good biocompatibility and no major adverse effects toward smooth muscle and endothelial cells in in vitro experiments. In this study, these alloys were investigated in a subcutaneous mouse model. Fluoride coated (fc) magnesium, as well as MgCa0.4%, MgCa0.6%, MgCa0.8%, MgCa1.0%, and a commercially available WE43 alloy were implanted in form of (fc) cylindrical plates into the subcutaneous tissue of NMRI mice. After a 3 and 6 months follow-up, the (fc) alloy plates were examined by histomorphometric techniques to assess their degradation rate in vivo. Our data indicate that all (fc) alloys showed a significant corrosion. For both time points the (fc) MgCa alloys showed a higher corrosion rate in comparison to the (fc) WE43 reference alloy. Significant adverse effects were not observed. Fluoride coating of magnesium-based alloys can be a suitable way to reduce degradation rates. However, the (fc) MgCa alloys did not exhibit decreased degradation kinetics in comparison to the (fc) WE43 alloy in a subcutaneous mouse model.

  18. Simultaneous measurements of magnesium, calcium and sodium influxes in perfused squid giant axons under membrane potential control.

    PubMed

    Rojas, E; Taylor, R E

    1975-10-01

    1. Giant axons from the squids Dosidicus gigas, Loligo forbesi and Loligo vulgaris were internally perfused with 550 or 275 mM KF plus sucrose and bathed in artificial sea water containing 45Ca, 28Mg or mixtures of 45Ca-28Mg or 45Ca-22Na. Resting influxes and extra influxes during voltage-clamp pulses were measured by collecting and counting the internal perfusate. 2. For Dosidicus axons in 10 mM-CaCl2 the resting influx of calcium was 0-016 +/- 0-007 p-mole/cm2 sec and a linear function of external concentration. For two experiments in 10 and 84-7 mM-CaCl2, 100 nM tetrodotoxin had no effect. Resting calcium influx in 10 mM-CaCl2 was 0-017 +/- 0-013 p-mole/cm2 sec for Loligo axons. 3. With 55 mM-MgCl2 outside the average resting magnesium influx was 0-124 +/- 0-080 p-mole/cm2 sec for Loligo axons. Discarding one aberrant point the value is 0-105 +/- 0-046 which is not significantly different from the resting calcium influx for Dosidicus fibres in 55 mM-CaCl2, given as 0-094 p-mole/cm2 sec by the regression line shown in Fig. 1. In two experiments 150 nM tetrodotoxin had no effect. 4. With 430 mM-NaCl outside 100 nM tetrodotoxin reduced the average resting influx of sodium in Dosidicus axon from 27-7 +/- 4-5 to 25-1 +/- 6-2 p-mole/cm2 sec and for Loligo fibres in 460 mM-NaCl from 50-5 +/- 4 to 20 +/- 8 p-mole/cm2 sec. 5. Using depolarizing pulses of various durations, the extra calcium influx occurred in two phases. The early phase was eliminated by external application of tetrodotoxin. The results of analysis are consistent with, but do not rigorously demonstrate, the conclusion that the tetrodotoxin sensitive calcium entry is flowing through the normal sodium channels (cf. Baker, Hodgkin & Ridgway, 1971). 6. Measurements of extra influxes using 22Na and 45Ca simultaneously indicate that the time courses of tetrodotoxin sensitive calcium and sodium entry are similar but not necessarily identical. It is very doubtful that any significant calcium entry occurs before

  19. Generation of composites for bone tissue-engineering applications consisting of gellan gum hydrogels mineralized with calcium and magnesium phosphate phases by enzymatic means.

    PubMed

    Douglas, Timothy E L; Krawczyk, Grzegorz; Pamula, Elzbieta; Declercq, Heidi A; Schaubroeck, David; Bucko, Miroslaw M; Balcaen, Lieve; Van Der Voort, Pascal; Bliznuk, Vitaliy; van den Vreken, Natasja M F; Dash, Mamoni; Detsch, Rainer; Boccaccini, Aldo R; Vanhaecke, Frank; Cornelissen, Maria; Dubruel, Peter

    2016-11-01

    Mineralization of hydrogels, desirable for bone regeneration applications, may be achieved enzymatically by incorporation of alkaline phosphatase (ALP). ALP-loaded gellan gum (GG) hydrogels were mineralized by incubation in mineralization media containing calcium and/or magnesium glycerophosphate (CaGP, MgGP). Mineralization media with CaGP:MgGP concentrations 0.1:0, 0.075:0.025, 0.05:0.05, 0.025:0.075 and 0:0.1 (all values mol/dm(3) , denoted A, B, C, D and E, respectively) were compared. Mineral formation was confirmed by IR and Raman, SEM, ICP-OES, XRD, TEM, SAED, TGA and increases in the the mass fraction of the hydrogel not consisting of water. Ca was incorporated into mineral to a greater extent than Mg in samples mineralized in media A-D. Mg content and amorphicity of mineral formed increased in the order A < B < C < D. Mineral formed in media A and B was calcium-deficient hydroxyapatite (CDHA). Mineral formed in medium C was a combination of CDHA and an amorphous phase. Mineral formed in medium D was an amorphous phase. Mineral formed in medium E was a combination of crystalline and amorphous MgP. Young's moduli and storage moduli decreased in dependence of mineralization medium in the order A > B > C > D, but were significantly higher for samples mineralized in medium E. The attachment and vitality of osteoblastic MC3T3-E1 cells were higher on samples mineralized in media B-E (containing Mg) than in those mineralized in medium A (not containing Mg). All samples underwent degradation and supported the adhesion of RAW 264.7 monocytic cells, and samples mineralized in media A and B supported osteoclast-like cell formation. Copyright © 2014 John Wiley & Sons, Ltd.

  20. Effect of calcium magnesium acetate on the forming property and fractal dimension of sludge pore structure during combustion.

    PubMed

    Zhang, Lihui; Duan, Feng; Huang, Yaji; Chyang, Chiensong

    2015-12-01

    The changes in pore structure characteristics of sewage sludge particles under effect of calcium magnesium acetate (CMA) during combustion were investigated, the samples were characterized by N2 isothermal absorption method, and the data were used to analyze the fractal properties of the obtained samples. Results show that reaction time and the mole ratio of calcium to sulfur (Ca/S ratio) have notable impact on the pore structure and morphology of solid sample. The Brunauer-Emmett-Teller (BET) specific surface area (SBET) of sample increases with Ca/S ratio, while significant decreases with reaction time. The fractal dimension D has the similar trend with that of SBET, indicating that the surface roughness of sludge increases under the effect of CMA adding, resulting in improved the sludge combustion and the desulfurization process.

  1. Measurement and calculation of the Stark-broadening parameters for the resonance lines of singly ionized calcium and magnesium.

    NASA Technical Reports Server (NTRS)

    Jones, W. W.; Sanchez, A.; Greig, J. R.; Griem, H. R.

    1972-01-01

    The electron-impact-broadened profiles of the resonance lines of singly ionized calcium and magnesium have been measured using an electromagnetically driven shock tube and a rapid-scanning Fabry-Perot spectrometer. For an electron density of 10 to the 17th power per cu cm and a temperature of 19,000 K, we found the Lorentzian half-width of the Ca+ line to be 0.086 A plus or minus 10% and of the Mg+ line to be 0.044 A plus or minus 10%. Using the quantum-mechanical theory of Barnes and Peach and our semiclassical calculation for the calcium lines, we found that the temperature dependence of the theoretical curves is close to that measured, although both theories predict actual values which are somewhat large.

  2. Deep SDSS optical spectroscopy of distant halo stars. II. Iron, calcium, and magnesium abundances

    NASA Astrophysics Data System (ADS)

    Fernández-Alvar, E.; Allende Prieto, C.; Schlesinger, K. J.; Beers, T. C.; Robin, A. C.; Schneider, D. P.; Lee, Y. S.; Bizyaev, D.; Ebelke, G.; Malanushenko, E.; Malanushenko, V.; Oravetz, D.; Pan, K.; Simmons, A.

    2015-05-01

    Aims: We analyze a sample of 3944 low-resolution (R ~ 2000) optical spectra from the Sloan Digital Sky Survey (SDSS), focusing on stars with effective temperatures 5800 ≤ Teff ≤ 6300 K, and distances from the Milky Way plane in excess of 5 kpc, and determine their abundances of Fe, Ca, and Mg. Methods: We followed the same methodology as in the previous paper in this series, deriving atmospheric parameters by χ2 minimization, but this time we obtained the abundances of individual elements by fitting their associated spectral lines. Distances were calculated from absolute magnitudes obtained by a statistical comparison of our stellar parameters with stellar-evolution models. Results: The observations reveal a decrease in the abundances of iron, calcium, and magnesium at large distances from the Galactic center. The median abundances for the halo stars analyzed are fairly constant up to a Galactocentric distance r ~ 20 kpc, rapidly decrease between r ~ 20 and r ~ 40 kpc, and flatten out to significantly lower values at larger distances, consistent with previous studies. In addition, we examine [Ca/Fe] and [Mg/Fe] as a function of [Fe/H] and Galactocentric distance. Our results show that the most distant parts of the halo show a steeper variation of [Ca/Fe] and [Mg/Fe] with iron. We found that at the range -1.6 < [Fe/H] < -0.4, [Ca/Fe] decreases with distance, in agreement with earlier results based on local stars. However, the opposite trend is apparent for [Mg/Fe]. Our conclusion that the outer regions of the halo are more metal-poor than the inner regions, based on in situ observations of distant stars, agrees with recent results based on inferences from the kinematics of more local stars, and with predictions of recent galaxy formation simulations for galaxies similar to the Milky Way. Table 1 and beginning of Tables 2 and 3 are available in electronic form at http://www.aanda.orgFull Tables 2 and 3 are only available at the CDS via anonymous ftp to http

  3. Calcium Carbonate Nucleation in an Alkaline Lake Surface Water, Pyramid Lake, Nevada, USA

    USGS Publications Warehouse

    Reddy, M.M.; Hoch, A.

    2012-01-01

    Calcium concentration and calcite supersaturation (??) needed for calcium carbonate nucleation and crystal growth in Pyramid Lake (PL) surface water were determined during August of 1997, 2000, and 2001. PL surface water has ?? values of 10-16. Notwithstanding high ??, calcium carbonate growth did not occur on aragonite single crystals suspended PL surface water for several months. However, calcium solution addition to PL surface-water samples caused reproducible calcium carbonate mineral nucleation and crystal growth. Mean PL surface-water calcium concentration at nucleation was 2.33 mM (n = 10), a value about nine times higher than the ambient PL surface-water calcium concentration (0.26 mM); mean ?? at nucleation (109 with a standard deviation of 8) is about eight times the PL surface-water ??. Calcium concentration and ?? regulated the calcium carbonate formation in PL nucleation experiments and surface water. Unfiltered samples nucleated at lower ?? than filtered samples. Calcium concentration and ?? at nucleation for experiments in the presence of added particles were within one standard deviation of the mean for all samples. Calcium carbonate formation rates followed a simple rate expression of the form, rate (mM/min) = A (??) + B. The best fit rate equation "Rate (?? mM/?? min) = -0.0026 ?? + 0.0175 (r = 0.904, n = 10)" was statistically significant at greater than the 0.01 confidence level and gives, after rearrangement, ?? at zero rate of 6.7. Nucleation in PL surface water and morphology of calcium carbonate particles formed in PL nucleation experiments and in PL surface-water samples suggest crystal growth inhibition by multiple substances present in PL surface water mediates PL calcium carbonate formation, but there is insufficient information to determine the chemical nature of all inhibitors. ?? 2011 U.S. Government.

  4. Calcium carbonate nucleation in an alkaline lake surface water, Pyramid Lake, Nevada, USA

    USGS Publications Warehouse

    Reddy, Michael M.; Hoch, Anthony

    2012-01-01

    Calcium concentration and calcite supersaturation (Ω) needed for calcium carbonate nucleation and crystal growth in Pyramid Lake (PL) surface water were determined during August of 1997, 2000, and 2001. PL surface water has Ω values of 10-16. Notwithstanding high Ω, calcium carbonate growth did not occur on aragonite single crystals suspended PL surface water for several months. However, calcium solution addition to PL surface-water samples caused reproducible calcium carbonate mineral nucleation and crystal growth. Mean PL surface-water calcium concentration at nucleation was 2.33 mM (n = 10), a value about nine times higher than the ambient PL surface-water calcium concentration (0.26 mM); mean Ω at nucleation (109 with a standard deviation of 8) is about eight times the PL surface-water Ω. Calcium concentration and Ω regulated the calcium carbonate formation in PL nucleation experiments and surface water. Unfiltered samples nucleated at lower Ω than filtered samples. Calcium concentration and Ω at nucleation for experiments in the presence of added particles were within one standard deviation of the mean for all samples. Calcium carbonate formation rates followed a simple rate expression of the form, rate (mM/min) = A (Ω) + B. The best fit rate equation "Rate (Δ mM/Δ min) = -0.0026 Ω + 0.0175 (r = 0.904, n = 10)" was statistically significant at greater than the 0.01 confidence level and gives, after rearrangement, Ω at zero rate of 6.7. Nucleation in PL surface water and morphology of calcium carbonate particles formed in PL nucleation experiments and in PL surface-water samples suggest crystal growth inhibition by multiple substances present in PL surface water mediates PL calcium carbonate formation, but there is insufficient information to determine the chemical nature of all inhibitors.

  5. Self-setting bioactive calcium-magnesium phosphate cement with high strength and degradability for bone regeneration.

    PubMed

    Wu, Fan; Wei, Jie; Guo, Han; Chen, Fangping; Hong, Hua; Liu, Changsheng

    2008-11-01

    Calcium phosphate cement (CPC) has been successfully used in clinics as bone repair biomaterial for many years. However, poor mechanical properties and a low biodegradation rate limit any further applications. Magnesium phosphate cement (MPC) is characterized by fast setting, high initial strength and relatively rapid degradation in vivo. In this study, MPC was combined with CPC to develop novel calcium-magnesium phosphate cement (CMPC). The setting time, compressive strength, phase composition of hardened cement, degradation in vitro, cells responses in vitro by MG-63 cell culture and tissue responses in vivo by implantation of CMPC in bone defect of rabbits were investigated. The results show that CMPC has a shorter setting time and markedly better mechanical properties than either CPC or MPC. Moreover, CMPC showed significantly improved degradability compared to CPC in simulated body fluid. Cell culture results indicate that CMPC is biocompatible and could support cell attachment and proliferation. To investigate the in vivo biocompatibility and osteogenesis, the CMPC samples were implanted into bone defects in rabbits. Histological evaluation showed that the introduction of MPC into CPC enhanced the efficiency of new bone formation. CMPC also exhibited good biocompatibility, biodegradability and osteoconductivity with host bone in vivo. The results obtained suggest that CMPC, having met the basic requirements of bone tissue engineering, might have a significant clinical advantage over CPC, and may have the potential to be applied in orthopedic, reconstructive and maxillofacial surgery.

  6. Surface properties of calcium and magnesium oxide nanopowders grafted with unsaturated carboxylic acids studied with inverse gas chromatography.

    PubMed

    Maciejewska, Magdalena; Krzywania-Kaliszewska, Alicja; Zaborski, Marian

    2012-09-28

    Inverse gas chromatography (IGC) was applied at infinite dilution to evaluate the surface properties of calcium and magnesium oxide nanoparticles and the effect of surface grafted unsaturated carboxylic acid on the nanopowder donor-acceptor characteristics. The dispersive components (γ(s)(D)) of the free energy of the nanopowders were determined by Gray's method, whereas their tendency to undergo specific interactions was estimated based on the electron donor-acceptor approach presented by Papirer. The calcium and magnesium oxide nanoparticles exhibited high surface energies (79 mJ/m² and 74 mJ/m², respectively). Modification of nanopowders with unsaturated carboxylic acids decreased their specific adsorption energy. The lowest value of γ(s)(D) was determined for nanopowders grafted with undecylenic acid, approximately 55 mJ/m². The specific interactions were characterised by the molar free energy (ΔG(A)(SP)) and molar enthalpy (ΔH(A)(SP)) of adsorption as well as the donor and acceptor interaction parameters (K(A), K(D)).

  7. Effect of gutta-percha solvents at different temperatures on the calcium, phosphorus and magnesium levels of human root dentin.

    PubMed

    Doğan, H; Taşman, F; Cehreli, Z C

    2001-08-01

    The aim of this study in vitro investigation was to evaluate the alterations caused by warmed gutta-percha solvents on the calcium, phosphorus and magnesium levels of root dentin. Extracted human anterior teeth, whose crowns and apical root thirds had been removed were used as root dentin specimens. The roots were sectioned longitudinally into two segments, cleaned and dried. Segments were divided into 12 groups (n=12). In 6 groups, the specimens received treatment with the following solvents at room temperature (22 degrees C): Chloroform, xylene, eucalyptol, orange oil, halothane and saline (control). Within each group, the specimens were further subgrouped into two to be incubated (100% humidity at 37 degrees C) for 5 and 10 min, respectively, following treatment with the solvents. The remaining six groups were treated with the same solvents which had been previously warmed to body temperature (37 degrees C) and received the same experimental procedures. The levels of calcium, phosphorus and magnesium in each specimen were analysed using energy dispersive spectrometric microanalysis. Statistical analysis of the readings showed that neither warming of the solvents nor prolonged incubation (treatment) time was capable of altering the histochemical composition of cut root dentin surfaces.

  8. Magnesium modification of a calcium phosphate cement alters bone marrow stromal cell behavior via an integrin-mediated mechanism.

    PubMed

    Zhang, Jing; Ma, Xiaoyu; Lin, Dan; Shi, Hengsong; Yuan, Yuan; Tang, Wei; Zhou, Huanjun; Guo, Han; Qian, Jiangchao; Liu, Changsheng

    2015-06-01

    The chemical composition, structure and surface characteristics of biomaterials/scaffold can affect the adsorption of proteins, and this in turn influences the subsequent cellular response and tissue regeneration. With magnesium/calcium phosphate cements (MCPC) as model, the effects of magnesium (Mg) on the initial adhesion and osteogenic differentiation of bone marrow stromal cells (BMSCs) as well as the underlying mechanism were investigated. A series of MCPCs with different magnesium phosphate cement (MPC) content (0∼20%) in calcium phosphate cement (CPC) were synthesized. MCPCs with moderate proportion of MPC (5% and 10%, referred to as 5MCPC and 10MCPC) were found to effectively modulate the orientation of the adsorbed fibronectin (Fn) to exhibit enhanced receptor binding affinity, and to up-regulate integrin α5β1 expression of BMSCs, especially for 5MCPC. As a result, the attachment, morphology, focal adhesion formation, actin filaments assembly and osteogenic differentiation of BMSCs on 5MCPC were strongly enhanced. Further in vivo experiments confirmed that 5MCPC induced promoted osteogenesis in comparison to ot her CPC/MCPCs. Our results also suggested that the Mg on the underlying substrates but not the dissolved Mg ions was the main contributor to the above positive effects. Based on these results, it can be inferred that the specific interaction of Fn and integrin α5β1 had predominant effect on the MCPC-induced enhanced cellular response of BMSCs. These results provide a new strategy to regulate BMSCs adhesion and osteogenic differentiation by adjusting the Mg/Ca content and distribution in CPC, guiding the development of osteoinductive scaffolds for bone tissue regeneration.

  9. The effect of zeolite A supplementation in the dry period on periparturient calcium, phosphorus, and magnesium homeostasis.

    PubMed

    Thilsing-Hansen, T; Jørgensen, R J; Enemark, J M D; Larsen, T

    2002-07-01

    One potential way of preventing parturient hypocalcemia in the dairy cow is to feed dry cow rations very low in calcium (<20 g/d); but, because it is difficult to formulate rations sufficiently low in calcium, this principle has been almost abandoned. Recent studies have shown, however, that it is possible to prevent milk fever, as well as subclinical hypocalcemia, by supplementing the dry cow ration with sodium aluminium silicate (zeolite A), which has the capacity to bind calcium. The aim of this study was to further evaluate the effect, if any, of such supplementation on other blood constituents, feed intake, and milk production in the subsequent lactation. A total of 31 pregnant dry cows about to enter their third or later lactation were assigned as experimental or control cows according to parity and expected date of calving. The experimental cows received 1.4 kg of zeolite pellets per d (0.7 kg of pure zeolite A) for the last 2 wk of pregnancy. Blood samples were drawn from all cows 1 wk before the expected date of calving, at calving, at d 1 and 2 after calving, and 1 wk after calving. Additionally, a urine sample was drawn 1 wk before the expected date of calving. Zeolite supplementation significantly increased the plasma calcium level on the day of calving, whereas plasma magnesium as well as inorganic phosphate was suppressed. Serum 1,25(OH)2D was significantly increased 1 wk before the expected date of calving among the experimental cows, whereas there was no difference in the urinary excretion of the bone metabolite deoxypyridinoline between the two groups. Feed intake was decreased among the zeolite-treated cows during the last 2 wk of pregnancy. No effect was observed on milk yield, milk fat, and milk protein in the subsequent lactation. The mechanisms and interactions involved in zeolite supplementation are discussed in relation to the observed improvement in parturient calcium homeostasis and to the observed depression in blood magnesium and

  10. Effects of calcium magnesium acetate on the combustion of coal-water slurries. Ninth quarterly project status report, 1 September 1991--30 November 1991

    SciTech Connect

    Levendis, Y.A.

    1991-12-31

    The general objective of the project is to investigate the combustion behavior of single and multiple Coal-Water Fuel (CWF) particles burning at high temperature environments. Both uncatalyzed as well as catalyzed CWF drops with Calcium Magnesium Acetate (CMA) catalyst will be studies. Emphasis will also be given in the effects of CMA on the sulfur capture during combustion.

  11. Potentiostatic pulse-deposition of calcium phosphate on magnesium alloy for temporary implant applications--an in vitro corrosion study.

    PubMed

    Kannan, M Bobby; Wallipa, O

    2013-03-01

    In this study, a magnesium alloy (AZ91) was coated with calcium phosphate using potentiostatic pulse-potential and constant-potential methods and the in vitro corrosion behaviour of the coated samples was compared with the bare metal. In vitro corrosion studies were carried out using electrochemical impedance spectroscopy and potentiodynamic polarization in simulated body fluid (SBF) at 37 °C. Calcium phosphate coatings enhanced the corrosion resistance of the alloy, however, the pulse-potential coating performed better than the constant-potential coating. The pulse-potential coating exhibited ~3 times higher polarization resistance than that of the constant-potential coating. The corrosion current density obtained from the potentiodynamic polarization curves was significantly less (~60%) for the pulse-deposition coating as compared to the constant-potential coating. Post-corrosion analysis revealed only slight corrosion on the pulse-potential coating, whereas the constant-potential coating exhibited a large number of corrosion particles attached to the coating. The better in vitro corrosion performance of the pulse-potential coating can be attributed to the closely packed calcium phosphate particles.

  12. 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

    2015-10-06

    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.

  13. Kinetic analysis of enhanced thermal stability of an alkaline protease with engineered twin disulfide bridges and calcium-dependent stability.

    PubMed

    Ikegaya, Kazuo; Sugio, Shigetoshi; Murakami, Kohji; Yamanouchi, Kouichi

    2003-01-20

    The thermal stability of a cysteine-free alkaline protease (Alp) secreted by the eukaryote Aspergillus oryzae was improved both by the introduction of engineered twin disulfide bridges (Cys-69/Cys-101 and Cys-169/Cys-200), newly constructed as part of this study, and by the addition of calcium ions. We performed an extensive kinetic analysis of the increased thermal stability of the mutants as well as the role of calcium dependence. The thermodynamic activation parameters for irreversible thermal inactivation, the activation free energy (deltaG), the activation enthalpy (deltaH), and the activation entropy (deltaS) were determined from absolute reaction rate theory. The values of deltaH and deltaS were significantly and concomitantly increased as a result of introducing the twin disulfide bridges, for which the increase in the value of deltaH outweighed that of deltaS, resulting in significant increases in the value of deltaG. The enhancement of the thermal stability obtained by introducing the twin disulfide bridges is an example of the so-called low-temperature stabilization of enzymes. The stabilizing effect of calcium ions on wild-type Alp is similar to the results we obtained by introducing the engineered twin disulfide bridges.

  14. Understanding growth mechanisms and tribocorrosion behaviour of porous TiO2 anodic films containing calcium, phosphorous and magnesium

    NASA Astrophysics Data System (ADS)

    Oliveira, Fernando G.; Ribeiro, Ana R.; Perez, Geronimo; Archanjo, Bráulio S.; Gouvea, Cristol P.; Araújo, Joyce R.; Campos, Andrea P. C.; Kuznetsov, Alexei; Almeida, Clara M.; Maru, Márcia M.; Achete, Carlos A.; Ponthiaux, Pierre; Celis, Jean-Pierre; Rocha, Luis A.

    2015-06-01

    The growth of the dental implant market increases the concern regarding the quality, efficiency, and lifetime of dental implants. Titanium and its alloys are dominant materials in this field thanks to their high biocompatibility and corrosion resistance, but they possess a very low wear resistance. Besides problems related to osteointegration and bacterial infections, tribocorrosion phenomena being the simultaneous action between corrosion and wear, are likely to occur during the lifetime of the implant. Therefore, tribocorrosion resistant surfaces are needed to guarantee the preservation of dental implants. This work focused on the incorporation of magnesium, together with calcium and phosphorous, in the structure of titanium oxide films produced by micro-arc oxidation (MAO). The characterization of morphology, chemical composition, and crystalline structure of the surfaces provided important insights leading to (1) a better understanding of the oxide film growth mechanisms during the MAO treatment; and (2) a better awareness on the degradation process during tribocorrosion tests. The addition of magnesium was shown to support the formation of rutile which improves the tribocorrosion properties of the surfaces.

  15. Zirconium, calcium, and strontium contents in magnesium based biodegradable alloys modulate the efficiency of implant-induced osseointegration.

    PubMed

    Mushahary, Dolly; Sravanthi, Ragamouni; Li, Yuncang; Kumar, Mahesh J; Harishankar, Nemani; Hodgson, Peter D; Wen, Cuie; Pande, Gopal

    2013-01-01

    Development of new biodegradable implants and devices is necessary to meet the increasing needs of regenerative orthopedic procedures. An important consideration while formulating new implant materials is that they should physicochemically and biologically mimic bone-like properties. In earlier studies, we have developed and characterized magnesium based biodegradable alloys, in particular magnesium-zirconium (Mg-Zr) alloys. Here we have reported the biological properties of four Mg-Zr alloys containing different quantities of strontium or calcium. The alloys were implanted in small cavities made in femur bones of New Zealand White rabbits, and the quantitative and qualitative assessments of newly induced bone tissue were carried out. A total of 30 experimental animals, three for each implant type, were studied, and bone induction was assessed by histological, immunohistochemical and radiological methods; cavities in the femurs with no implants and observed for the same period of time were kept as controls. Our results showed that Mg-Zr alloys containing appropriate quantities of strontium were more efficient in inducing good quality mineralized bone than other alloys. Our results have been discussed in the context of physicochemical and biological properties of the alloys, and they could be very useful in determining the nature of future generations of biodegradable orthopedic implants.

  16. Probing the limit of magnesium uptake by β-tricalcium phosphate in biphasic mixtures formed from calcium deficient apatites

    SciTech Connect

    Kumar, P. Nandha; Mishra, Sandeep K.; Kannan, S.

    2015-11-15

    A series of magnesium doped non-stoichiometric calcium deficient apatites were synthesized through an aqueous precipitation route. The resultant structural changes during heat treatment were investigated by X-ray diffraction, Raman and FT-IR spectroscopy and Rietveld refinement. The results confirmed the formation of biphasic mixtures comprising Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2} and β-Ca{sub 3}(PO{sub 4}){sub 2} after heat treatment at 1000 °C with the preferential occupancy of Mg{sup 2+} at the crystal lattice of β-Ca{sub 3}(PO{sub 4}){sub 2}. The concentration of Mg{sup 2+} uptake in β-Ca{sub 3}(PO{sub 4}){sub 2} is limited till reaching the stoichiometric ratio of (Ca+Mg)/P=1.67 and beyond this stoichiometric value [(Ca+Mg)/P>1.67], Mg{sup 2+} precipitates as Mg(OH){sub 2} and thereafter gets converted to MgO during heat treatment. Any kind of Mg{sup 2+} uptake in the crystal lattice of Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2} is discarded from the investigation. - Highlights: • Aqueous co-precipitation of calcium deficient apatites with excess magnesium (Mg{sup 2+}) additions. • Heat treatments beyond 800 °C results in the formation of biphasic apatite mixtures. • Mg{sup 2+} gets accommodated at the β-Ca{sub 3}(PO{sub 4}){sub 2} lattice of biphasic mixtures. • Mg{sup 2+} additions exceeding stoichiometric value (Ca/P>1.67) results in its formation as MgO. • Mg{sup 2+} occupancy at β-Ca{sub 3}(PO{sub 4}){sub 2} lattice delays its allotropic conversion α-Ca{sub 3}(PO{sub 4}){sub 2} till 1350 °C.

  17. The effects of calcium magnesium acetate (CMA) deicing material on the water quality of Bear Creek, Clackamas County, Oregon, 1999

    USGS Publications Warehouse

    Tanner, Dwight Q.; Wood, Tamara M.

    2000-01-01

    This report presents the results of a study by the U.S. Geological Survey, done in cooperation with the Oregon Department of Transportation (ODOT), to evaluate the effects of the highway deicing material, calcium magnesium acetate (CMA), on the water quality of Bear Creek, in the Cascade Range of Oregon. ODOT began using CMA (an alternative deicer that has fewer adverse environmental effects than road salt) in the mid-1990s and began this study with the USGS to ensure that there were no unexpected effects on the water quality of Bear Creek. Streamflow, precipitation, dissolved oxygen, pH, specific conductance, and water temperature were measured continuously through the 1998?99 winter. There was no measurable effect of the application of CMA to Highway 26 on the biochemical oxygen demand (BOD), calcium concentration, or magnesium concentration of Bear Creek and its tributaries. BOD was small in all of the water samples, some of which were collected before CMA application, and some of which were collected after application. Five-day BOD values ranged from 0.1 milligrams per liter to 1.5 milligrams per liter, and 20-day BOD values ranged from 0.2 milligrams per liter to 2.0 milligrams per liter. Dissolved copper concentrations in a small tributary ditch on the north side of Highway 26 exceeded the U.S. Environmental Protection Agency aquatic life criteria on three occasions. These exceedances were probably not caused by the application of CMA because (1) one of the samples was a background sample (no recent CMA application), and (2) dissolved copper was not detected in Bear Creek water samples to which CMA was added during laboratory experiments.

  18. Production of low-cost calcium magnesium acetate (CMA) as an environmentally friendly deicer from cheese whey

    SciTech Connect

    Yang, S.T.; Zhu, H.; Li, Y.; Tang, I.C.

    1993-12-31

    About 28 billion lbs of cheese whey are being wasted in the US because of the high biological oxygen demand (BOD) of whey, disposing of surplus whey is a pollution problem. An innovative, wide-scale solution to the whey disposal problem is to use whey as a zero- or low-cost feedstock for the production of an environmentally safe, noncorrosive, road deicer-calcium magnesium acetate (CMA). CMA can be used to replace some of the 10 to 14 million tons road salt used in the North America for deicing. A novel anaerobic fermentation process is developed to produce calcium magnesium acetate (CMA) from whey permeate. A co-culture consisting of homolactic (S. lactis) and homoacetic (C. formicoaceticum) bacteria was used to convert whey lactose to lactate and then to acetate in continuous, immobilized cell bioreactors. The acetate yield from lactose was {approximately}95% (wt/wt), and the final concentration of acetic acid was 4%. The acetic acid present in the fermentation broth can be recovered by solvent-extraction with a tertiary amine and reacted with dolomitic lime (Ca/MgO) to form a concentrated (>25%) CMA solution. About 25 tons CMA can be produced from a plant processing 1 million lbs whey permeate (4.5% lactose) per day. The production costs are estimated at {approximately}$220/ton CMA, which is only about one third of the present market price for CMA deicer. Therefore, about 0.8 million tons/yr CMA deicer can be produced from the currently unused whey. This will partially fulfill market demand for economically and environmentally sound chemicals for roadway deicing. This also will provide a viable solution to the whey disposal problem currently facing many dairies in the North America.

  19. Microwave assisted synthesis and characterization of magnesium substituted calcium phosphate bioceramics.

    PubMed

    Khan, Nida Iqbal; Ijaz, Kashif; Zahid, Muniza; Khan, Abdul S; Abdul Kadir, Mohammed Rafiq; Hussain, Rafaqat; Anis-Ur-Rehman; Darr, Jawwad A; Ihtesham-Ur-Rehman; Chaudhry, Aqif A

    2015-11-01

    Hydroxyapatite is used extensively in hard tissue repair due to its biocompatibility and similarity to biological apatite, the mineral component of bone. It differs subtly in composition from biological apatite which contains other ions such as magnesium, zinc, carbonate and silicon (believed to play biological roles). Traditional methods of hydroxyapatite synthesis are time consuming and require strict reaction parameter control. This paper outlines synthesis of magnesium substituted hydroxyapatite using simple microwave irradiation of precipitated suspensions. Microwave irradiation resulted in a drastic decrease in ageing times of amorphous apatitic phases. Time taken to synthesize hydroxyapatite (which remained stable upon heat treatment at 900°C for 1h) reduced twelve folds (to 2h) as compared to traditionally required times. The effects of increasing magnesium concentration in the precursors on particle size, surface area, phase-purity, agglomeration and thermal stability, were observed using scanning electron microscopy, BET surface area analysis, X-ray diffraction and photo acoustic Fourier transform infra-red spectroscopy. Porous agglomerates were obtained after a brief heat-treatment (1h) at 900°C.

  20. DETERMINATION OF MATERNAL SERUM ZINC, IRON, CALCIUM AND MAGNESIUM DURING PREGNANCY IN PREGNANT WOMEN AND UMBILICAL CORD BLOOD AND THEIR ASSOCIATION WITH OUTCOME OF PREGNANCY

    PubMed Central

    Khoushabi, Fahimeh; Shadan, Mohammad Reza; Miri, Ali; Sharifi-Rad, Javad

    2016-01-01

    Background: Trace elements and specially minerals are critical for the development of fetus. Many minerals are transferred to the fetus for fetal stores in the latter part of the pregnancy. It has been shown that various trace elements such as Zinc, Iron, Calcium and Magnesium are metabolically interrelated and there is alteration in their concentration during pregnancy. Beyond pregnancy is associated with increased demand of all the nutrients and deficiency of any of these could affect pregnancy, delivery and outcome of pregnancy. Aim: To study the levels of trace elements namely zinc, iron, magnesium and calcium in maternal and umbilical cord blood and their association with pregnancy outcome. Methods: Sixty pregnant women in Zabol, Iran were selected from those who had registered their names for the prenatal care and who had followed up till the 3rd trimester of pregnancy ending in child birth. Biochemical parameters analyzed with help of the biochemical laboratory. Data were analyzed by SPSS software. Results: The mean biochemical profile such, serum calcium, magnesium, zinc and iron in the pregnant women were as follow: in the 1st trimester 8.3, 1.9, 74.9 and 74.4 µg/dl respectively; in the 2nd trimester 8.5, 1.9, 73.1 and 79.3 µg/dl, respectively; in the 3rd trimester 8.6, 1.9, 68.4, and 82.2 µg/dl, respectively. In the umbilical cord blood, the mean serum calcium, magnesium, zinc and iron were 8.5, 1.9, 84.1, and 89.8 µg/dl, respectively. The mean serum calcium and magnesium during the three trimesters of pregnancy were not significantly different from that in the umbilical cord blood, while the mean serum zinc and iron in the umbilical cord blood were significantly different (p<0.05) in the three trimester of pregnancy. The mean birth weight of neonates was 3.1 kg and 12% of neonates showed low birth weight. Our findings showed that, except magnesium, the profile of other biochemical variables, namely, calcium, zinc and iron in the umbilical cord blood

  1. Effects of seawater alkalinity on calcium and acid-base regulation in juvenile European lobster (Homarus gammarus) during a moult cycle.

    PubMed

    Middlemiss, Karen L; Urbina, Mauricio A; Wilson, Rod W

    2016-03-01

    Fluxes of NH4(+) (acid) and HCO3(-) (base), and whole body calcium content were measured in European lobster (Homarus gammarus) during intermoult (megalopae stage), and during the first 24h for postmoult juveniles under control (~2000 μeq/L) and low seawater alkalinity (~830 μeq/L). Immediately after moulting, animals lost 45% of the total body calcium via the shed exoskeleton (exuvia), and only 11% was retained in the uncalcified body. At 24h postmoult, exoskeleton calcium increased to ~46% of the intermoult stage. Ammonia excretion was not affected by seawater alkalinity. After moulting, bicarbonate excretion was immediately reversed from excretion to uptake (~4-6 fold higher rates than intermoult) over the whole 24h postmoult period, peaking at 3-6h. These data suggest that exoskeleton calcification is not completed by 24h postmoult. Low seawater alkalinity reduced postmoult bicarbonate uptake by 29% on average. Net acid-base flux (equivalent to net base uptake) followed the same pattern as HCO3(-) fluxes, and was 22% lower in low alkalinity seawater over the whole 24h postmoult period. The common occurrence of low alkalinity in intensive aquaculture systems may slow postmoult calcification in juvenile H. gammarus, increasing the risk of mortalities through cannibalism.

  2. Exogenous oestrogen affects calcium metabolism differently from exogenous testosterone in ovariectomized or orchiectomized rats fed a high fructose diet severely deficient in magnesium.

    PubMed

    Koh, E T; Owen, W L; Om, A S

    1996-03-01

    To investigate interactions between sex hormones, dietary fructose, and a severe magnesium deficiency on calcium metabolism, 10 week old ovariectomized (OVX) female, and orchiectomized (ORX) males rats were studied. The OVX and ORX animals were divided into two groups: one half of the animals in each group was injected with beta-oestradiol-3-benzoate dissolved in sesame oil twice a week; the other half was injected with testosterone cypionate in sesame oil twice a week. All animals were pari-fed a severely magnesium-deficient fructose diet. After a 4 week experimental period, a 24 h urine sample was collected for measurements of cAMP, calcium, magnesium, and phosphorus. Blood was collected for determination of calcium, magnesium, phosphorus, 25-hydroxy- and 1.25-dihydroxycholecalciferol [25(OH)D, 1.25(OH)2D], and parathyroid hormone (PTH). Femurs were used for measurements of bone mineral content (BMC) and density (BMD). Oestrogen treatment produced hypercalcaemia and hypercalciuria, and, further, this was higher in female than in male rats. In contrast, testosterone treatment produced hypocalcaemia and hypocalciuria. Hypocalcaemia in testosterone-treated animals may stimulate secretion of PTH. Testosterone-treated animals had significantly lower BMD than oestrogen-treated animals. High circulating PTH seemed to cause bone loss in the testosterone group. High PTH may stimulate hydroxylation of 25(OH) D to 1.25(OH)2D in the kidneys, and high circulating 1.25(OH)2D would antagonize bone formation. Either endogenous or exogenous oestrogen increased kidney calcification. The study indicates that oestrogen-fructose-magnesium interaction on calcium metabolism was significantly different from that of testosterone.

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

    PubMed

    Elmore, Amy R

    2005-01-01

    L-Ascorbic Acid, Calcium Ascorbate, Magnesium Ascorbate, Magnesium Ascorbyl Phosphate, Sodium Ascorbate, and Sodium Ascorbyl Phosphate function in cosmetic formulations primarily as antioxidants. Ascorbic Acid is commonly called Vitamin C. Ascorbic Acid is used as an antioxidant and pH adjuster in a large variety of cosmetic formulations, over 3/4 of which were hair dyes and colors at concentrations between 0.3% and 0.6%. For other uses, the reported concentrations were either very low (<0.01%) or in the 5% to 10% range. Calcium Ascorbate and Magnesium Ascorbate are described as antioxidants and skin conditioning agents--miscellaneous for use in cosmetics, but are not currently used. Sodium Ascorbyl Phosphate functions as an antioxidant in cosmetic products and is used at concentrations ranging from 0.01% to 3%. Magnesium Ascorbyl Phosphate functions as an antioxidant in cosmetics and was reported being used at concentrations from 0.001% to 3%. Sodium Ascorbate also functions as an antioxidant in cosmetics at concentrations from 0.0003% to 0.3%. Related ingredients (Ascorbyl Palmitate, Ascorbyl Dipalmitate, Ascorbyl Stearate, Erythorbic Acid, and Sodium Erythorbate) have been previously reviewed by the Cosmetic Ingredient Review (CIR) Expert Panel and found "to be safe for use as cosmetic ingredients in the present practices of good use." Ascorbic Acid is a generally recognized as safe (GRAS) substance for use as a chemical preservative in foods and as a nutrient and/or dietary supplement. Calcium Ascorbate and Sodium Ascorbate are listed as GRAS substances for use as chemical preservatives. L-Ascorbic Acid is readily and reversibly oxidized to L-dehydroascorbic acid and both forms exist in equilibrium in the body. Permeation rates of Ascorbic Acid through whole and stripped mouse skin were 3.43 +/- 0.74 microg/cm(2)/h and 33.2 +/- 5.2 microg/cm(2)/h. Acute oral and parenteral studies in mice, rats, rabbits, guinea pigs, dogs, and cats demonstrated little toxicity

  4. Subcellular concentrations of calcium, zinc, and magnesium in benign nodular hyperplasia of the human prostate: X-ray microanalysis of freeze-dried cryosections

    SciTech Connect

    Tvedt, K.E.; Kopstad, G.; Haugen, O.A.; Halgunset, J.

    1987-01-01

    Biopsies from human prostates were obtained from normal and hyperplastic glands. The intracellular concentrations of calcium, zinc, and magnesium were analyzed using X-ray microanalysis of freeze-dried cryosections. Two prostate biopsies were obtained from kidney donors, ages 19 and 50 years, without any sign of benign nodular hyperplasia. The normal tissues were frozen within 15 min after circulatory arrest. The central part of biopsies from eight elderly men suffering from benign nodular hyperplasia were frozen within 30 s after excision. Adjacent tissue was processed for light microscopy and histopathological diagnosis. All samples were fresh-frozen using liquid nitrogen cooled pliers, without the use of any freeze-protection, fixation, or staining. In both the normal and the hyperplastic prostates high concentrations (up to above 100 mmol/kg dry weight) of zinc were present in electron dense bodies in the cytoplasm of the epithelial cells. Together with zinc, about equal concentrations of magnesium were found. Calcium was detected in 4 to 8 times the concentration of zinc. Significant, positive correlation between calcium and zinc as well as between calcium and magnesium in the cytoplasm was a typical finding in both normal and hyperplastic glands. In six of eight patients, older than 60 years of age, high levels of calcium (17.0-38.8 mmol/kg dry weight) were observed in the nuclei of the epithelial cells, while very low values were found in the remaining two. In the two younger cases (19 and 50 years of age), the nuclear calcium level in prostatic epithelium was relatively low (about 10 mmol/kg dry weight). These observations suggest that an increase of intranuclear calcium with advancing age may be of pathogenetic significance to growth disturbances in the prostate.

  5. Petrographic evidence of calcium oxychloride formation in mortars exposed to magnesium chloride solution

    SciTech Connect

    Sutter, Lawrence . E-mail: cee@mtu.edu; Peterson, Karl . E-mail: cee@mtu.edu; Touton, Sayward . E-mail: cee@mtu.edu; Van Dam, Tom . E-mail: cee@mtu.edu; Johnston, Dan . E-mail: Dan.Johnston@state.sd.us

    2006-08-15

    Many researchers have reported chemical interactions between CaCl{sub 2} and MgCl{sub 2} solutions and hardened Portland cement paste. One potentially destructive phase reported in the literature is calcium oxychloride (3CaO.CaCl{sub 2}.15H{sub 2}O). In the past, limited numbers of researchers have reported identification of this phase by X-ray diffraction. In this work, petrographic evidence of oxychloride formation is presented based on optical microscopy, scanning electron microscopy and microanalysis. This evidence indicates that calcium oxychloride does form in mortars exposed to MgCl{sub 2} solutions.

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

    PubMed

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

    2010-10-01

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

  7. Effects of calcium, magnesium, and sodium on alleviating cadmium toxicity to Hyalella azteca

    USGS Publications Warehouse

    Jackson, B.P.; Lasier, P.J.; Miller, W.P.; Winger, P.V.

    2000-01-01

    Toxicity of trace metal ions to aquatic organisms, arising through either anthropogenic inputs or acidification of surface waters, continues to be both a regulatory and environmental problem. It is generally accepted that the free metal ion is the major toxic species (Florence et a1.,1992) and that inorganic or organic complexation renders the metal ion non-bioavailable (Meador, 1991, Galvez and Wood, 1997). However, water chemistry parameters such as alkalinity, hardness, dissolved organic carbon and pH influence metal ion toxicity either directly by lowering free metal ion concentration or indirectly through synergistic or antagonistic effects. Alkalinity and salinity can affect the speciation of metal ions by increasing ion-pair formation, thus decreasing free metal ion concentration. For example, Cu was found to be less toxic to rainbow trout in waters of high alkalinity (Miller and Mackay, 1980), due to formation of CuCO3 ion pair, and corresponding reduction in free Cu2+ concentration. The influence of salinity on the toxicity of cadmium to various organisms has been demonstrated in a number of studies (Bervoets et al., 1995, Hall et al., 1995, Lin and Dunson, 1993, Blust et al., 1992). In all these studies the apparent toxicity of cadmium was lowered as salinity was increased due to increased formation of CdC1+ and CDCl2 aqueous complexes that are non-toxic or of much lower toxicity than the free Cd2+ ion. Changes in pH exert both a biological and chemical effect on metal ion toxicity (Campbell and Stokes, 1985). Low pH favors greater metal ion solubility, and, in the absence of complexing ions, reduced speciation of the metal ion, which tends to increase toxicity compared to higher pH. However, Iow pH also enhances competition between H+ and metal ion for cell surface binding sites, which tends to decrease metal ion toxicity.

  8. DEGRADATION OF SM2ZR2O7 THERMAL BARRIER COATING CAUSED BY CALCIUM-MAGNESIUM-ALUMINUM-SILICON OXIDE (CMAS) DEPOSITION

    SciTech Connect

    Wang, Honglong; Sheng, Zhizhi; Tarwater, Emily; Zhang, Xingxing; Dasgupta, Sudip; Fergus, Jeffrey

    2015-03-16

    Rare earth zirconates are promising materials for use as thermal barrier coatings in gas turbine engines. Among the lanthanide zirconate materials, Sm2Zr2O7 with the pyrochlore structure has lower thermal conductivity and better corrosion resistance against calcium-magnesium-aluminum-silicon oxide (CMAS). In this work, after reaction with CMAS, the pyrochlore structure transforms to the cubic fluorite structure and Ca2Sm8(SiO4)6O2 forms in elongated grain.

  9. Computational Material Modeling of Hydrated Cement Paste Calcium Silicate Hydrate (C-S-H) Chemistry Structure - Influence of Magnesium Exchange on Mechanical Stiffness: C-S-H Jennite

    DTIC Science & Technology

    2015-04-27

    scales. Features and changes in material chemistry /nano scale influence the hydration process, formed micro scale morphology, associated properties...hydrated cement paste constituent - calcium silicate hydrate (C-S-H) based on its material chemistry structure are studied following a molecular dynamics... Chemistry Structure - Influence of Magnesium Exchange on Mechanical Stiffness: C- S-H Jennite The views, opinions and/or findings contained in this

  10. Alterations of serum zinc, copper, manganese, iron, calcium, and magnesium concentrations and the complexity of interelement relations in patients with obsessive-compulsive disorder.

    PubMed

    Shohag, Hasanuzzaman; Ullah, Ashik; Qusar, Shalahuddin; Rahman, Mustafizur; Hasnat, Abul

    2012-09-01

    The purpose of the present study was to evaluate the status of serum trace elements: zinc, copper, manganese, iron, calcium, and magnesium concentrations in obsessive-compulsive disorder patients. Forty-eight obsessive-compulsive disorder patients and 48 healthy volunteers were included in this study. Patients were recruited from Bangabandhu Sheikh Mujib Medical University by random sampling. Serum trace element concentrations were determined using flame atomic absorption spectroscopy (for zinc, copper, iron, calcium, and magnesium) as well as graphite furnace atomic absorption spectroscopy (for manganese). Data were analyzed using independent t test, Pearson's correlation analysis, regression analysis, and ANOVA. Statistical analysis of these data showed a definite pattern of variation among certain elements in patients with obsessive-compulsive disorder compared to controls. In patients' serum, zinc, iron, and magnesium concentrations decreased significantly (p<0.05) compared to the controls. Serum manganese and calcium concentrations were significantly higher (p<0.05) in patients compared to the controls. These data showed a definite imbalance in the interelement relations in obsessive-compulsive disorder patients compared to controls and therefore suggest a disturbance in the element homeostasis.

  11. Extracellular calcium acts as a “third messenger” to regulate enzyme and alkaline secretion

    PubMed Central

    Caroppo, Rosa; Gerbino, Andrea; Fistetto, Gregorio; Colella, Matilde; Debellis, Lucantonio; Hofer, Aldebaran M.; Curci, Silvana

    2004-01-01

    It is generally assumed that the functional consequences of stimulation with Ca2+-mobilizing agonists are derived exclusively from the second messenger action of intracellular Ca2+, acting on targets inside the cells. However, during Ca2+ signaling events, Ca2+ moves in and out of the cell, causing changes not only in intracellular Ca2+, but also in local extracellular Ca2+. The fact that numerous cell types possess an extracellular Ca2+ “sensor” raises the question of whether these dynamic changes in external [Ca2+] may serve some sort of messenger function. We found that in intact gastric mucosa, the changes in extracellular [Ca2+] secondary to carbachol-induced increases in intracellular [Ca2+] were sufficient and necessary to elicit alkaline secretion and pepsinogen secretion, independent of intracellular [Ca2+] changes. These findings suggest that extracellular Ca2+ can act as a “third messenger” via Ca2+ sensor(s) to regulate specific subsets of tissue function previously assumed to be under the direct control of intracellular Ca2+. PMID:15240573

  12. Phenomenon and mechanism of capsule shrinking in alkaline solution containing calcium ions.

    PubMed

    She, Shupeng; Shan, Bowen; Li, Qinqin; Tong, Weijun; Gao, Changyou

    2012-11-15

    Shrinking phenomenon of poly(allylamine hydrochloride) (PAH)/poly(styrene sulfonate, sodium salt) (PSS) multilayer microcapsules was observed when they were incubated in alkaline solutions containing Ca(2+). The shrinking was universal to those polyelectrolyte multilayer capsules regardless of the wall thickness and wall compositions suppose the conditions were proper. The shrinking extent increased along with the increase of solution pH and Ca(2+) concentration, and reached to a maximum value of 70% (from 7.4 to 2.3 μm). The shrunk capsules with a hollow structure and thick wall could well maintain their spherical shape in a dry state. During the capsule shrinking partial loss of the polyelectrolytes especially PSS took place, and the loss amount increased along with the increase of solution pH although the alteration patterns were different at lower Ca(2+) concentration. The complexation of PSS with Ca(2+), which is believed one of the major reasons governing the capsule shrinking, was demonstrated by X-ray photoelectron spectroscopy and turbidity experiment. The mechanism is proposed, which relies on the synergistic effects of deprotonation of PAH and screening of PSS by Ca(2+) leading to the thermodynamically favored-capsule shrinking.

  13. Crystallization behavior and kinetics of calcium carbonate in highly alkaline and supersaturated system

    NASA Astrophysics Data System (ADS)

    Zhu, Ganyu; Li, Huiquan; Li, Shaopeng; Hou, Xinjuan; Xu, Dehua; Lin, Rongyi; Tang, Qing

    2015-10-01

    In causticization process of Na2CO3-Ca(OH)2, which is a liquid-solid system with high alkalinity and supersaturation, agglomeration and morphology instability of CaCO3 crystal have greatly limited its application. To deeply investigate the internal relations between crystallization process and condition control in this system, crystallization kinetics was conducted in a continuously operated crystallizer. The kinetic equations of growth rate, nucleation rate and agglomeration kernel were correlated in terms of power law kinetic expressions based on the agglomeration population balance equation. Magma density and mean residence time exert a considerable effect on crystal growth, nucleation, and agglomeration. Crystal growth and nucleation are surface-integration-limited and size-limited, respectively. Agglomeration increases with increasing mean residence time, but the increase in magma density break down the agglomerates by frequent and energetic collisions. Through the study, crystallization behavior of CaCO3 in causticization system was revealed, and the particle size and morphology were efficiently predicted and controlled. These results can provide a basis for understanding the design of the reactor.

  14. Distribution of calcium (Ca) and magnesium (Mg) in the leaves of Brassica rapa under varying exogenous Ca and Mg supply

    PubMed Central

    Rios, Juan Jose; Ó Lochlainn, Seosamh; Devonshire, Jean; Graham, Neil S.; Hammond, John P.; King, Graham J.; White, Philip J.; Kurup, Smita; Broadley, Martin R.

    2012-01-01

    Background and Aims Leafy vegetable Brassica crops are an important source of dietary calcium (Ca) and magnesium (Mg) and represent potential targets for increasing leaf Ca and Mg concentrations through agronomy or breeding. Although the internal distribution of Ca and Mg within leaves affects the accumulation of these elements, such data are not available for Brassica. The aim of this study was to characterize the internal distribution of Ca and Mg in the leaves of a vegetable Brassica and to determine the effects of altered exogenous Ca and Mg supply on this distribution. Methods Brassica rapa ssp. trilocularis ‘R-o-18’ was grown at four different Ca:Mg treatments for 21 d in a controlled environment. Concentrations of Ca and Mg were determined in fully expanded leaves using inductively coupled plasma-mass spectrometry (ICP-MS). Internal distributions of Ca and Mg were determined in transverse leaf sections at the base and apex of leaves using energy-dispersive X-ray spectroscopy (EDS) with cryo-scanning electron microscopy (cryo-SEM). Key Results Leaf Ca and Mg concentrations were greatest in palisade and spongy mesophyll cells, respectively, although this was dependent on exogenous supply. Calcium accumulation in palisade mesophyll cells was enhanced slightly under high Mg supply; in contrast, Mg accumulation in spongy mesophyll cells was not affected by Ca supply. Conclusions The results are consistent with Arabidopsis thaliana and other Brassicaceae, providing phenotypic evidence that conserved mechanisms regulate leaf Ca and Mg distribution at a cellular scale. The future study of Arabidopsis gene orthologues in mutants of this reference B. rapa genotype will improve our understanding of Ca and Mg homeostasis in plants and may provide a model-to-crop translation pathway for targeted breeding. PMID:22362665

  15. Response of sediment calcium and magnesium species to the regional acid deposition in eutrophic Taihu Lake, China.

    PubMed

    Tao, Yu; Dan, Dai; Chengda, He; Qiujin, Xu; Fengchang, Wu

    2016-11-01

    Acid deposition causes carbonate dissolution in watersheds and leads to profound impacts on water chemistry of lakes. Here, we presented a detailed study on the seasonal, spatial, and vertical variations of calcium and magnesium species in the overlying water, interstitial water, and sediment profiles in eutrophic Taihu Lake under the circumstance of regional acid deposition. The result showed that both the acid deposition and biomineralization in Taihu Lake had effects on Ca and Mg species. In the lake water, calcium carbonate was saturated or over-saturated based on long-term statistical calculation of the saturation index (SI). On the sediment profiles, significant difference in Ca and Mg species existed between the surface sediment (0-10 cm) and deeper sediments (>10 cm). The interstitial water Ca(2+) and Mg(2+), ion-exchangeable Ca and Mg in the surface sediment were higher than those in the deeper sediment. In the spring, when the acid deposition is more intensive, the acid-extracted Ca and Mg in the surface sediment were lower than that in the deeper sediment in the northwest lake, due to carbonate dissolution caused by the regional acid deposition. Spatially, the higher concentration of acid-extracted Ca and Mg in the northwest surface sediment than that in the east lake was observed, indicating the pronounced carbonate biomineralization by algae bloom in the northwest lake. Statistical analysis showed that acid deposition exerted a stronger impact on the variation of acid-extracted Ca and Mg in the surface sediment than the biomineralization in Taihu Lake. For the total Ca and Mg concentration in the spring, however, no significant change between the surface and deeper sediment in the northwest lake was observed, indicating that the carbonate precipitation via biomineralization and the carbonate dissolution due to acidic deposition were in a dynamic balance. These features are of major importance for the understanding of combined effects of acid

  16. Micromorphological effect of calcium phosphate coating on compatibility of magnesium alloy with osteoblast

    PubMed Central

    Hiromoto, Sachiko; Yamazaki, Tomohiko

    2017-01-01

    Abstract Octacalcium phosphate (OCP) and hydroxyapatite (HAp) coatings were developed to control the degradation speed and to improve the biocompatibility of biodegradable magnesium alloys. Osteoblast MG-63 was cultured directly on OCP- and HAp-coated Mg-3Al-1Zn (wt%, AZ31) alloy (OCP- and HAp-AZ31) to evaluate cell compatibility. Cell proliferation was remarkably improved with OCP and HAp coatings which reduced the corrosion and prevented the H2O2 generation on Mg alloy substrate. OCP-AZ31 showed sparse distribution of living cell colonies and dead cells. HAp-AZ31 showed dense and homogeneous distribution of living cells, with dead cells localized over and around corrosion pits, some of which were formed underneath the coating. These results demonstrated that cells were dead due to changes in the local environment, and it is necessary to evaluate the local biocompatibility of magnesium alloys. Cell density on HAp-AZ31 was higher than that on OCP-AZ31 although there was not a significant difference in the amount of Mg ions released in medium between OCP- and HAp-AZ31. The outer layer of OCP and HAp coatings consisted of plate-like crystal with a thickness of around 0.1 μm and rod-like crystals with a diameter of around 0.1 μm, respectively, which grew from a continuous inner layer. Osteoblasts formed focal contacts on the tips of plate-like OCP and rod-like HAp crystals, with heights of 2–5 μm. The spacing between OCP tips of 0.8–1.1 μm was wider than that between HAp tips of 0.2–0.3 μm. These results demonstrated that cell proliferation depended on the micromorphology of the coatings which governed spacing of focal contacts. Consequently, HAp coating is suitable for improving cell compatibility and bone-forming ability of the Mg alloy. PMID:28179963

  17. Dietary magnesium and urolithiasis in growing calves.

    PubMed

    Kallfelz, F A; Ahmed, A S; Wallace, R J; Sasangka, B H; Warner, R G

    1987-01-01

    The effect of high levels of dietary magnesium (1.4%) alone or in combination with elevated calcium (1.8%) or phosphorus (1.6%) on growth and health of male calves was evaluated during a nine week feeding trial after weaning. Twenty calves were randomly divided into 4 feeding groups consisting of controls, high magnesium, high magnesium and calcium or high magnesium and phosphorus. Elevated dietary minerals caused decreased feed intake and growth rate. Blood urea nitrogen and serum creatinine levels were greatly elevated in calves fed high magnesium or magnesium and phosphorus and serum urea nitrogen was moderately elevated in calves fed high magnesium and calcium. These elevations suggested the occurrence of renal damage as a result of microcrystalline obstruction of renal tubules. Serum magnesium levels were three times normal in calves fed high magnesium or magnesium and phosphorus, but only twice normal in calves fed high magnesium and calcium. High dietary magnesium resulted in a significant depression in blood calcium level. This effect was somewhat overcome by additional dietary calcium Three calves fed the high magnesium diet and two calves fed the high magnesium and phosphorus diet developed urinary tract obstruction. The chemical composition of uroliths recovered from these calves was calcium apatite. Elevated dietary magnesium has been shown to be a cause of urolithiasis in growing male calves. Additional dietary calcium, but not phosphorus, appears to protect calves against urolithiasis induced by elevated dietary magnesium.

  18. Quantitative Proteomic Analysis of the Response to Zinc, Magnesium, and Calcium Deficiency in Specific Cell Types of Arabidopsis Roots

    PubMed Central

    Fukao, Yoichiro; Kobayashi, Mami; Zargar, Sajad Majeed; Kurata, Rie; Fukui, Risa; Mori, Izumi C.; Ogata, Yoshiyuki

    2016-01-01

    The proteome profiles of specific cell types have recently been investigated using techniques such as fluorescence activated cell sorting and laser capture microdissection. However, quantitative proteomic analysis of specific cell types has not yet been performed. In this study, to investigate the response of the proteome to zinc, magnesium, and calcium deficiency in specific cell types of Arabidopsis thaliana roots, we performed isobaric tags for relative and absolute quantification (iTRAQ)-based quantitative proteomics using GFP-expressing protoplasts collected by fluorescence-activated cell sorting. Protoplasts were collected from the pGL2-GFPer and pMGP-GFPer marker lines for epidermis or inner cell lines (pericycle, endodermis, and cortex), respectively. To increase the number of proteins identified, iTRAQ-labeled peptides were separated into 24 fractions by OFFGFEL electrophoresis prior to high-performance liquid chromatography coupled with mass spectrometry analysis. Overall, 1039 and 737 proteins were identified and quantified in the epidermal and inner cell lines, respectively. Interestingly, the expression of many proteins was decreased in the epidermis by mineral deficiency, although a weaker effect was observed in inner cell lines such as the pericycle, endodermis, and cortex. Here, we report for the first time the quantitative proteomics of specific cell types in Arabidopsis roots. PMID:28248212

  19. FTIR study on phase behavior of magnesium-doped biphasic calcium phosphate synthesized via sol-gel method

    NASA Astrophysics Data System (ADS)

    Toibah, A. R.; Sopyan, I.; Yuhazri, Y. Mohd; Jeefferie, R. A.; Nooririnah, O.

    2012-06-01

    Incorporation of metal as sintering additive is a simple way to improve physical and mechanical properties of biphasic calcium phosphate (BCP) materials as well as its performance in biomedical applications. In this work, magnesium (Mg) was incorporated into the BCP as sintering additive to improve the properties of BCP. The aim of this work was to study the effect of Mg doping to the BCP on its phase behavior. Mg-doped BCP powders have been synthesized via sol-gel method. The as prepared powders at different Mg concentration were calcined at different temperatures ranged from 500°C to 900°C. FT-IR technique was used to study the phase behavior and thermal stability of as prepared powders. FT-IR study revealed that the intensity of the OH band of HA phase was increased with the powder crystallinity and calcination temperature. FT-IR analysis confirmed the formation of biphasic mixtures of HA and Mg stabilized β-TCP in the synthesized powders when calcined at high temperatures as bands of HPO4-2 and P2O7-4 decreased. Moreover, FT-IR study also showed that the intensity of peak resolution of OH and PO4 bands are viewed less intensity with the increased in Mg percent concentration. FT-IR also revealed the presence of stable phase of P2O5 band at 400-450 cm-1 which promotes the crystal growth Mg-doped BCP powder.

  20. Automated Measurement of Magnesium/Calcium Ratios in Gastropod Shells Using Laser-induced Breakdown Spectroscopy for Paleoclimatic Applications.

    PubMed

    Cobo, Adolfo; García-Escárzaga, Asier; Gutiérrez-Zugasti, Igor; Setién, Jesús; González-Morales, Manuel R; López-Higuera, José Miguel

    2017-01-01

    The chemical composition of mollusk shells offers information about environmental conditions present during the lifespan of the organism. Shells found in geological deposits and in many archeological sites can help to reconstruct past climatic conditions. For example, a correlation has been found between seawater temperature and the amount of some substituent elements (e.g., magnesium, strontium) in the biogenerated calcium carbonate matrix of the shell, although it is very species-specific. Here we propose the use laser-induced breakdown spectroscopy (LIBS) to estimate Mg/Ca ratios in modern specimens of the common limpet Patella vulgata. An automated setup was used to obtain a sequence of Mg/Ca ratios across a sampling path that could be compared with the seawater temperatures recorded during the organism's lifespan. Results using four shells collected in different months of the year showed a direct relationship between the Mg/Ca ratios and the seawater temperature, although the sequences also revealed small-scale (short-term) variability and an irregular growth rate. Nevertheless, it was possible to infer the season of capture and the minimum and maximum seawater temperatures from the LIBS sequences. This fact, along with the reduction in sampling and measurement time compared with other spectrometric techniques (such as inductively coupled plasma mass spectrometry [ICP-MS]), makes LIBS useful in paleoclimatic studies.

  1. Calcium and magnesium elimination enhances accumulation of cardenolides in callus cultures of endemic Digitalis species of Turkey.

    PubMed

    Sahin, G; Verma, S K; Gurel, E

    2013-12-01

    Elimination of calcium (Ca), magnesium (Mg) or both from the medium of callus cultures of Digitalis davisiana Heywood, Digitalis lamarckii Ivanina, Digitalis trojana Ivanina and Digitalis cariensis Boiss. ex Jaub. et Spach increased cardenolides production. Callus was induced from hypocotyl segments from one-month old seedlings were cultured on MS medium containing 0.5 μg ml(-1) thidiazuron (TDZ) and 0.25 μg ml(-1) indole acetic acid (IAA). After 30 days of culture, callus was transferred in hormone-free MS medium (MSO) as well as Ca or Mg or both were completely eliminated from same medium. The amount of five cardenolides from D. davisiana Heywood, D. lamarckii Ivanina, D. trojana Ivanina and D. cariensis Boiss. ex Jaub. et Spach were compared. Higher amounts of five cardenolides and total cardenolides were obtained when callus of four Digitalis species were incubated on MS medium lacking both Ca and Mg. The mean contents of total cardenolides obtained were in the order of D. lamarckii (2017.97 μg g(-1))>D. trojana (1385.75 μg g(-1))>D. cariensis (1038.65 μg g(-1))>D. davisiana (899.86 μg g(-1)) when both Ca and Mg were eliminated from the medium, respectively. This protocol is useful for development of new strategies for the large-scale production of cardenolides.

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

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  3. Calcium-magnesium carbonate solid solutions from Holocene conglomerate cements and travertines in the Coast Range of California

    USGS Publications Warehouse

    Barnes, I.; O'Neil, J.R.

    1971-01-01

    Two calcium-magnesium carbonate solid solutions form Holocene travertines and conglomerate cements in fresh water stream channels of the Coast Range of California. Calcite does not yield the {015} diffraction maximum. The {006} diffraction maximum is lacking over most of the range of composition of calcite. Calcite has compositions from CaCO3 to Ca0.5Mg0.5CO3. Dolomite yields both the {006} and {015} diffraction maxima over its entire composition range, Ca0.6Mg0.4CO3 to Ca0.5Mg0.5CO3. The Ca-Mg carbonates form in isotopic equilibrium and thermodynamic disequilibrium from dispersion of Ca2+-rich water into CO32--rich water within the alluvium. The stable isotope data suggest that all the Mg-rich carbonates are primary precipitates and not a result of Mg-substitution in precursor CaCO3. There is a correlation between ??C13 and Mg content of the carbonates which predicts a 5%. fractionation of C13 between dolomite and calcite at sedimentary temperatures. C14 is incorporated in Ca-Mg carbonates forming from C13-poor meteoric waters and C13-rich waters from Cretaceous sediments. C14 ages of the Ca-Mg carbonates are apparent, and cannot be corrected to absolute values. Solution rates of calcite decrease with increasing MgCO3 content; dolomite dissolves slower than any calcite. ?? 1971.

  4. Evaluation of calcium magnesium acetate and road salt for contact hypersensitivity potential and dermal irritancy in humans.

    PubMed

    Cushman, J R; Duff, V A; Buteau, G H; Aust, L B; Caldwell, N; Lazer, W

    1991-04-01

    Calcium magnesium acetate (CMA) and road salt are both de-icing agents to which workers may be dermally exposed. A commercial formulation of CMA (Chevron Ice-B-Gon Deicer) and road salt were tested in a human repeat insult patch test to evaluate the contact hypersensitivity potential of these materials and to evaluate irritation following single or multiple applications. 72 of the initial 82 panelists completed the study. CMA and road salt (each at 10% and 30% w/w in distilled water; 0.3 ml) were administered under occlusive patches on the forearm for 14 h 3 x per week for 3 weeks. The panelists were challenged 2 weeks later; 2 panelists who had mild reactions were subsequently rechallenged 6 weeks later. Neither CMA nor road salt produced contact hypersensitivity in any panelists. Following the first application, moderate acute irritation was observed only at 1 skin site exposed to 30% road salt. Repeated exposure to CMA or road salt produced mild to moderate irritation. The highest incidence of moderate irritation was observed with 30% road salt. Thus, neither material is expected to cause significant dermal effects in exposed workers. CMA is expected to cause dermal irritation equivalent to or less than that caused by road salt.

  5. Estimation of calcium, magnesium, cadmium, and lead in biological samples from paralyzed quality control and production steel mill workers.

    PubMed

    Afridi, Hassan Imran; Talpur, Farah Naz; Kazi, Tasneem Gul; Kazi, Naveed; Arain, Sadaf Sadia; Shah, Faheem

    2015-06-01

    The determination of trace and toxic metals in the biological samples of human beings is an important clinical screening procedure. The aim of the present study was to compare the level of essential trace and toxic elements cadmium (Cd), calcium (Ca), lead (Pb), and magnesium (Mg) in biological samples (whole blood, urine, and scalp hair) of male paralyzed production (PPW) and quality control workers (PQW) of a steel mill, age ranged (35-55 years). For comparison purposes, healthy age-matched exposed referent subjects (EC), working in steel mill and control subjects (NEC), who were not working in industries and lived far away from the industrial areas, were selected as control subjects. The concentrations of electrolytes and toxic elements in biological samples were measured by atomic absorption spectrometry after microwave-assisted acid digestion. The validity and accuracy of the methodology were checked using certified reference materials. The results of this study showed that the mean values of Cd and Pb were significantly higher in scalp hair, blood, and urine samples of PPW and PQW as compared to NEC and EC (p < 0.001), whereas the concentrations of Ca and Mg were found to be lower in the scalp hair and blood but higher in the urine samples of PPW and PQW. The results show the need for immediate improvements in workplace, ventilation, and industrial hygiene practices.

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

    PubMed

    Bautista-Gallego, J; Arroyo-López, F N; Durán-Quintana, M C; Garrido-Fernandez, A

    2008-07-01

    A quantitative investigation on the individual effects of sodium (NaCl), potassium (KCl), calcium (CaCl2), and magnesium (MgCl2) chloride salts against Lactobacillus pentosus and Saccharomyces cerevisiae, two representative microorganisms of table olives and other fermented vegetables, was carried out. In order to assess their potential activities, both the kinetic growth parameters and dose-response profiles in synthetic media (deMan Rogosa Sharpe broth medium and yeast-malt-peptone-glucose broth medium, respectively) were obtained and analyzed. Microbial growth was monitored via optical density measurements as a function of contact time in the presence of progressive chloride salt concentrations. Relative maximum specific growth rate and lag-phase period were modeled as a function of the chloride salt concentrations. Moreover, for each salt and microorganism tested, the noninhibitory concentrations and the MICs were estimated and compared. All chloride salts exerted a significant antimicrobial effect on the growth cycle; particularly, CaCl2 showed a similar effect to NaCl, while KCl and MgCl2 were progressively less inhibitory. Microbial susceptibility and resistance were found to be nonlinearly dose related.

  7. Quantitative Proteomic Analysis of the Response to Zinc, Magnesium, and Calcium Deficiency in Specific Cell Types of Arabidopsis Roots.

    PubMed

    Fukao, Yoichiro; Kobayashi, Mami; Zargar, Sajad Majeed; Kurata, Rie; Fukui, Risa; Mori, Izumi C; Ogata, Yoshiyuki

    2016-01-12

    The proteome profiles of specific cell types have recently been investigated using techniques such as fluorescence activated cell sorting and laser capture microdissection. However, quantitative proteomic analysis of specific cell types has not yet been performed. In this study, to investigate the response of the proteome to zinc, magnesium, and calcium deficiency in specific cell types of Arabidopsis thaliana roots, we performed isobaric tags for relative and absolute quantification (iTRAQ)-based quantitative proteomics using GFP-expressing protoplasts collected by fluorescence-activated cell sorting. Protoplasts were collected from the pGL2-GFPer and pMGP-GFPer marker lines for epidermis or inner cell lines (pericycle, endodermis, and cortex), respectively. To increase the number of proteins identified, iTRAQ-labeled peptides were separated into 24 fractions by OFFGFEL electrophoresis prior to high-performance liquid chromatography coupled with mass spectrometry analysis. Overall, 1039 and 737 proteins were identified and quantified in the epidermal and inner cell lines, respectively. Interestingly, the expression of many proteins was decreased in the epidermis by mineral deficiency, although a weaker effect was observed in inner cell lines such as the pericycle, endodermis, and cortex. Here, we report for the first time the quantitative proteomics of specific cell types in Arabidopsis roots.

  8. Precursor preparation for Ca-Al layered double hydroxide to remove hexavalent chromium coexisting with calcium and magnesium chlorides

    NASA Astrophysics Data System (ADS)

    Zhong, Lihua; He, Xiaoman; Qu, Jun; Li, Xuewei; Lei, Zhiwu; Zhang, Qiwu; Liu, Xinzhong

    2017-01-01

    Al(OH)3 and Ca(OH)2 powders are co-ground to prepare a precursor which hydrates into a layered double hydroxide (LDH) phase by agitation in aqueous solution with target hexavalent chromium (Cr(VI)) at room temperature, to achieve an obvious improvement in removal efficiency of Cr(VI) through an easy incorporation into the structure. Although the prepared precursor transforms into LDH phases also when agitated in the solutions of calcium and magnesium chlorides, it incorporates Cr(VI) preferentially to the chloride salts when they coexist. The adsorption isotherm and kinetic studies show that the phenomena occurring on the Al-Ca precursor fit a pseudo-second-order kinetics with a Langmuir adsorption capacity of 59.45 mg/g. Besides, characterizations of the prepared precursor and the samples after adsorption are also performed by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Transmission electron microscope (TEM) to understand the reason of the preferential incorporation of Cr(VI) to the coexisting chloride salts during the LDH phase formation.

  9. Calcium and Magnesium Ions Modulate the Oligomeric State and Function of Mitochondrial 2-Cys Peroxiredoxins in Leishmania Parasites.

    PubMed

    Morais, Mariana A B; Giuseppe, Priscila O; Souza, Tatiana A C B; Castro, Helena; Honorato, Rodrigo V; Oliveira, Paulo S L; Netto, Luis E S; Tomas, Ana M; Murakami, Mario T

    2017-03-14

    Leishmania parasites have evolved a number of strategies to cope with the harsh environmental changes during mammalian infection. One of these mechanisms involves the functional gain that allowed mitochondrial 2-Cys peroxiredoxins to act as molecular chaperones when forming decamers. This function was demonstrated to be critical for the parasite infectivity in mammals and its activation was considered to be controlled exclusively by the enzyme redox state under physiological conditions. Herein, we revealed that magnesium and calcium ions play a major role in modulating the ability of these enzymes to act as molecular chaperones, surpassing the redox effect. These ions are directly involved in the mitochondrial metabolism and now also integrate a novel mechanism to stabilize the decameric form of 2-Cys peroxiredoxins in Leishmania mitochondrion. Moreover, we demonstrated that a constitutively dimeric Prx1m mutant impairs Leishmania's survival under heat stress, supporting the central role of chaperone function of Prx1m for Leishmania parasites during the transition from insect to mammalian hosts.

  10. Stabilization/solidification of mercury-contaminated waste ash using calcium sodium phosphate (CNP) and magnesium potassium phosphate (MKP) processes.

    PubMed

    Cho, Jae Han; Eom, Yujin; Lee, Tai Gyu

    2014-08-15

    This study examined the stabilization and solidification (S/S) of mercury (Hg)-contaminated waste ash generated from an industrial waste incinerator using chemically bonded phosphate ceramic (CBPC) technology. A magnesium potassium phosphate (MKP; MgKPO4 · 6H2O) ceramic, fabricated from MgO and KH2PO4, and a calcium sodium phosphate (CNP; CaNaPO4) ceramic, fabricated from CaO and Na2HPO4, were used as solidification binders in the CBPC process, and Na2S or FeS was added to each solidification binder to stabilize the Hg-contaminated waste ash. The S/S processes were conducted under various operating conditions (based on the solidification binder and stabilization reagent, stabilization reagent dosage, and waste loading ratio), and the performance characteristics of the S/S sample under each operating condition were compared, including the Hg leaching value and compressive strength. The Hg leaching value of untreated Hg-contaminated waste ash was 231.3 μg/L, whereas the S/S samples treated using the MKP and CNP processes exhibited Hg leaching values below the universal treatment standard (UTS) limit (25 μg/L). Although the compressive strengths of the S/S samples decreased as the sulfide dosage and waste loading ratio were increased, most of the S/S samples fabricated by the MKP and CNP processes exhibited good mechanical properties.

  11. Contribution of elevated intracellular calcium to pulmonary arterial myocyte alkalinization during chronic hypoxia

    PubMed Central

    Luke, Trevor; Shimoda, Larissa A.

    2016-01-01

    Abstract In the lung, exposure to chronic hypoxia (CH) causes pulmonary hypertension, a debilitating disease. Development of this condition arises from increased muscularity and contraction of pulmonary vessels, associated with increases in pulmonary arterial smooth muscle cell (PASMC) intracellular pH (pHi) and Ca2+ concentration ([Ca2+]i). In this study, we explored the interaction between pHi and [Ca2+]i in PASMCs from rats exposed to normoxia or CH (3 weeks, 10% O2). PASMC pHi and [Ca2+]i were measured with fluorescent microscopy and the dyes BCECF and Fura-2. Both pHi and [Ca2+]i levels were elevated in PASMCs from hypoxic rats. Exposure to KCl increased [Ca2+]i and pHi to a similar extent in normoxic and hypoxic PASMCs. Conversely, removal of extracellular Ca2+ or blockade of Ca2+ entry with NiCl2 or SKF 96365 decreased [Ca2+]i and pHi only in hypoxic cells. Neither increasing pHi with NH4Cl nor decreasing pHi by removal of bicarbonate impacted PASMC [Ca2+]i. We also examined the roles of Na+/Ca2+ exchange (NCX) and Na+/H+ exchange (NHE) in mediating the elevated basal [Ca2+]i and Ca2+-dependent changes in PASMC pHi. Bepridil, dichlorobenzamil, and KB-R7943, which are NCX inhibitors, decreased resting [Ca2+]i and pHi only in hypoxic PASMCs and blocked the changes in pHi induced by altering [Ca2+]i. Exposure to ethyl isopropyl amiloride, an NHE inhibitor, decreased resting pHi and prevented changes in pHi due to changing [Ca2+]i. Our findings indicate that, during CH, the elevation in basal [Ca2+]i may contribute to the alkaline shift in pHi in PASMCs, likely via mechanisms involving reverse-mode NCX and NHE. PMID:27076907

  12. Biocorrosion resistance of coated magnesium alloy by microarc oxidation in electrolyte containing zirconium and calcium salts

    NASA Astrophysics Data System (ADS)

    Wang, Ya-Ming; Guo, Jun-Wei; Wu, Yun-Feng; Liu, Yan; Cao, Jian-Yun; Zhou, Yu; Jia, De-Chang

    2014-09-01

    The key to use magnesium alloys as suitable biodegradable implants is how to adjust their degradation rates. We report a strategy to prepare biocompatible ceramic coating with improved biocorrosion resistance property on AZ91D alloy by microarc oxidation (MAO) in a silicate-K2ZrF6 solution with and without Ca(H2PO4)2 additives. The microstructure and biocorrosion of coatings were characterized by XRD and SEM, as well as electrochemical and immersion tests in simulated body fluid (SBF). The results show that the coatings are mainly composed of MgO, Mg2SiO4, m-ZrO2 phases, further Ca containing compounds involve the coating by Ca(H2PO4)2 addition in the silicate-K2ZrF6 solution. The corrosion resistance of coated AZ91D alloy is significantly improved compared with the bare one. After immersing in SBF for 28 d, the Si-Zr5-Ca0 coating indicates a best corrosion resistance performance.

  13. Effects of foliar sprays containing calcium, magnesium and titanium on plum (Prunus domestica L.) fruit quality.

    PubMed

    Alcaraz-Lopez, Carlos; Botia, Maria; Alcaraz, Carlos F; Riquelme, Fernando

    2003-12-01

    An experiment was performed in which Ti(4+)-ascorbate was sprayed onto plum trees in several combinations with other commercial compounds containing Ca2+ and Mg2+ to study the effects on the commercial quality of fruits, with special focus on improving their resistance against postharvest handling damage. All the treatments containing titanium increased the tree performance (branch elongation, flowering and fruit setting intensities) and fruit size. At harvest fruits from the Ti-treated trees showed improved resistance to compression and penetration, as well as a decrease in weight-loss during postharvest storage. A similar response was obtained for the external colour, though all the treatments seemed to delay somewhat the apparent ripening status. Nevertheless, the fruits from Ti-treated trees showed a better behaviour in the evolution of the colour parameters during storage than did the control fruits. Titanium application significantly increased the calcium, iron, copper and zinc concentrations in peel and flesh. This improvement in the calcium absorption is explained as a consequence of the beneficial effect of titanium on the absorption, translocation and assimilation processes.

  14. Study of the protein-bound fraction of calcium, iron, magnesium and zinc in bovine milk

    NASA Astrophysics Data System (ADS)

    Silva, Fernando V.; Lopes, Gisele S.; Nóbrega, Joaquim A.; Souza, Gilberto B.; Nogueira, Ana Rita A.

    2001-10-01

    Two approaches were used to study the interaction of Ca, Fe, Mg and Zn with bovine milk proteins by inductively coupled plasma optical emission spectrometry (ICPOES). Selective separations in bovine milk samples were accomplished employing an acid protein precipitation using 100 g l -1 trichloroacetic acid (TCA), and an enzymatic protein hydrolysis using 50 g l -1 pepsin (PEP) solution, respectively. The results were compared with total mineral contents determined after microwave-assisted acid digestion. The results obtained by enzymatic and acid precipitation evidenced the different interaction forms of Ca, Fe, Mg and Zn in the system formed by milk components. Iron was not solubilized by the TCA treatment, but was recovered completely after the enzymatic treatment. Quantitative recoveries of Ca, Mg and Zn were obtained using both approaches, showing that these analytes were bound to milk compounds affected by either treatment. Calcium, Mg and Zn are mainly associated with colloidal calcium phosphate and Fe is bound to the backbone of the casein polypeptide chain, cleaved by pepsin enzyme. The proposed approaches could be used to assess the complexity of these chemical interactions.

  15. Short term spatio-temporal variability of soil water-extractable calcium and magnesium after a low severity grassland fire in Lithuania.

    NASA Astrophysics Data System (ADS)

    Pereira, Paulo; Martin, David

    2014-05-01

    Fire has important impacts on soil nutrient spatio-temporal distribution (Outeiro et al., 2008). This impact depends on fire severity, topography of the burned area, type of soil and vegetation affected, and the meteorological conditions post-fire. Fire produces a complex mosaic of impacts in soil that can be extremely variable at small plot scale in the space and time. In order to assess and map such a heterogeneous distribution, the test of interpolation methods is fundamental to identify the best estimator and to have a better understanding of soil nutrients spatial distribution. The objective of this work is to identify the short-term spatial variability of water-extractable calcium and magnesium after a low severity grassland fire. The studied area is located near Vilnius (Lithuania) at 54° 42' N, 25° 08 E, 158 masl. Four days after the fire, it was designed in a burned area a plot with 400 m2 (20 x 20 m with 5 m space between sampling points). Twenty five samples from top soil (0-5 cm) were collected immediately after the fire (IAF), 2, 5, 7 and 9 months after the fire (a total of 125 in all sampling dates). The original data of water-extractable calcium and magnesium did not respected the Gaussian distribution, thus a neperian logarithm (ln) was applied in order to normalize data. Significant differences of water-extractable calcium and magnesium among sampling dates were carried out with the Anova One-way test using the ln data. In order to assess the spatial variability of water-extractable calcium and magnesium, we tested several interpolation methods as Ordinary Kriging (OK), Inverse Distance to a Weight (IDW) with the power of 1, 2, 3 and 4, Radial Basis Functions (RBF) - Inverse Multiquadratic (IMT), Multilog (MTG), Multiquadratic (MTQ) Natural Cubic Spline (NCS) and Thin Plate Spline (TPS) - and Local Polynomial (LP) with the power of 1 and 2. Interpolation tests were carried out with Ln data. The best interpolation method was assessed using the

  16. Effects of magnesium chloride and organic additives on the synthesis of aragonite precipitated calcium carbonate

    NASA Astrophysics Data System (ADS)

    Park, Woon Kyoung; Ko, Sang-Jin; Lee, Seung Woo; Cho, Kye-Hong; Ahn, Ji-Whan; Han, Choon

    2008-05-01

    The synthesis of aragonite precipitated calcium carbonate by treating a suspension of Ca(OH) 2 with CO 2 gas was investigated with regard to the effects of Mg 2+ ions and organic additives on polymorphism and alternative orientations. In the presence of a small amount of Mg 2+, Mg-calcite formed, but as the Mg 2+ ion concentration increased, the amount of Mg-calcite decreased and the amount of aragonite increased. Thus, the formation of Mg-calcite is suppressed and only aragonite is formed in the presence of 60 mol% MgCl 2. As the Mg 2+ ion concentration increased, the aragonite that formed was found to have decreased in terms of its longitude and aspect ratio. Furthermore, the effect of Mg 2+ ions in conjunction with organic additives was also investigated with regard to polymorphs and morphology and the structure-forming properties of the organic additives.

  17. Magnesium deficiency and metabolic syndrome: stress and inflammation may reflect calcium activation.

    PubMed

    Rayssiguier, Yves; Libako, Patrycja; Nowacki, Wojciech; Rock, Edmond

    2010-06-01

    Magnesium (Mg) intake is inadequate in the western diet and metabolic syndrome is highly prevalent in populations around the world. Epidemiological studies suggest that high Mg intake may reduce the risk but the possibility of confounding factors exists, given the strong association between Mg and other beneficial nutriments (vegetables, fibers, cereals). The concept that metabolic syndrome is an inflammatory condition may explain the role of Mg.Mg deficiency results in a stress effect and increased susceptibility to physiological damage produced by stress. Stress activates the hypothalamic-pituitary-adrenal axis (HPA) axis and the sympathetic nervous system. The activation of the renin-angiotensin-aldosterone system is a factor in the development of insulin resistance by increasing oxidative stress. In both humans and rats, aldosteronism results in an immunostimulatory state and leads to an inflammatory phenotype. Stress response induces the release of large quantities of excitatory amino acids and activates the nuclear factor NFkappaB, promoting translation of molecules involved in cell regulation, metabolism and apoptosis. The rise in neuropeptides is also well documented. Stress-induced HPA activation has been identified to play an important role in the preferential body fat accumulation but evidence that Mg is involved in body weight regulation is lacking. One of the earliest events in the acute response to stress is endothelial dysfunction. Endothelial cells actively contribute to inflammation by elaborating cytokines, synthesizing chemical mediators and expressing adhesion molecules. Experimental Mg deficiency in rats induces a clinical inflammatory syndrome characterized by leukocyte and macrophage activation, synthesis of inflammatory cytokines and acute phase proteins, extensive production of free radicals. An increase in extracellular Mg concentration decreases inflammatory effects, while reduction in extracellular Mg results in cell activation. The

  18. Relative importance of calcium and magnesium in hardness-based modification of copper toxicity

    SciTech Connect

    Welsh, P.G.; Lipton, J.; Chapman, G.A.; Podrabsky, T.L.

    2000-06-01

    Because of the relationship between water hardness and the toxicity of many metals, total hardness is used as a model parameter to calculate ambient water quality criteria for copper and other metals. However, the relative contribution of the Ca and Mg components of total hardness as modifiers of metals toxicity is not considered in the water quality criteria. Acute Cu toxicity was measured in rainbow trout (Oncorhynchus mykiss) and chinook salmon (O. tshawytscha) swim-up fry in laboratory waters that were formulated to have similar total hardness and alkalinity but different Ca and Mg concentrations. Experiments were performed at nominal total hardness values of 40 and 90 mg/L (as CaCO{sub 3}). In four paired toxicity tests, acute Cu toxicity was significantly lower, i.e., 96-h LC50s were higher, in laboratory waters containing proportionately more Ca (Ca:Mg molar ratios of 1.5--5.2) than in waters containing less Ca (Ca:Mg molar ratios of 0.2--0.8). the relative increase in the 96-h Cu LC50 at higher Ca concentrations, but similar total hardness concentrations, was between 29 and 86% when the low Ca treatment was similar to American Society for Testing and Materials laboratory water. Failure to account for differences in Ca when matching or adjusting for total hardness thus exerts an important influence on the prediction of metal toxicity. These differences must be addressed in water-effect ratio testing in which paired tests with laboratory and site waters are conducted.

  19. Beneficial effect of pollen and/or propolis on the metabolism of iron, calcium, phosphorus, and magnesium in rats with nutritional ferropenic anemia.

    PubMed

    Haro, A; López-Aliaga, I; Lisbona, F; Barrionuevo, M; Alférez, M J; Campos, M S

    2000-11-01

    There has been considerable debate regarding the nutritional benefits of pollen and the propolis produced by bees, although most contributions have lacked scientific soundness. This paper describes the possible beneficial effect of their use in pharmacological products in cases of anemic syndrome. We studied the effect of these two natural products on the digestive utilization of iron, calcium, phosphorus, and magnesium, using control rats and rats with nutritional ferropenic anemia. The addition of these products to the diet produced a positive effect on weight gain; this fact could constitute a scientific basis for the application of pollen and propolis as fortifiers. They improve the digestive utilization of iron and the regeneration efficiency of hemoglobin, especially during recovery from an anemic syndrome. They also have a positive effect on phosphocalcic metabolism and maintain an appropiate level of magnesium metabolism. Furthermore, in iron-deficient rats, these natural products palliate, to a large extent, the adverse effects of iron deficiency on calcium and magnesium metabolism as a result of the improvement in the digestive utilization of these minerals.

  20. Magnesium toxicosis in two horses.

    PubMed

    Henninger, R W; Horst, J

    1997-07-01

    Magnesium sulfate, a saline laxative, is often used for treatment of intestinal impactions in horses. Clinical signs of hypermagnesemia are an uncommon complication following oral administration of magnesium sulfate. Overdose of magnesium sulfate in combination with renal insufficiency, hypocalcemia, or compromise of intestinal integrity may predispose horses to magnesium toxicosis. Establishment of diuresis with fluids and IV administration of calcium may provide successful treatment of magnesium toxicosis in horses.

  1. Calcium-phosphate coatings obtained biomimetically on magnesium substrates under low magnetic field

    NASA Astrophysics Data System (ADS)

    Yanovska, A.; Kuznetsov, V.; Stanislavov, A.; Danilchenko, S.; Sukhodub, L.

    2012-09-01

    A simple method of hydroxyapatite (HA) coating deposition on Mg substrates at 37 °C is proposed. It was established that variation of ionic composition of the initial solution leads to the deposition of coatings with various phase composition, i.e. DCPD, DCPD + HA, HA which decreased corrosion rate of Mg. The paper also discusses the crystallization of dicalcium phosphate dehydrate (DCPD) and HA coatings on Mg substrates obtained by dipping method under the permanent magnetic field (0.3 T) in the neighborhood of the north and the south pole. A difference in particle morphology and crystal texture of precipitates in the north pole and the south pole proximity was observed. Lattice parameters of DCPD coatings obtained near opposite magnet poles were calculated using XRD results. It was found that the proximity to the south pole of magnet increases the crystallinity of calcium-phosphates. Increase of crystallite sizes in (0 2 0) and (0 4 0) plane was observed for DCPD in the presence of magnetic field.

  2. Establishing homology between mitochondrial calcium uniporters, prokaryotic magnesium channels and chlamydial IncA proteins.

    PubMed

    Lee, Andre; Vastermark, Ake; Saier, Milton H

    2014-08-01

    Mitochondrial calcium uniporters (MCUs) (TC no. 1.A.77) are oligomeric channel proteins found in the mitochondrial inner membrane. MCUs have two well-conserved transmembrane segments (TMSs), connected by a linker, similar to bacterial MCU homologues. These proteins and chlamydial IncA proteins (of unknown function; TC no. 9.B.159) are homologous to prokaryotic Mg(2+) transporters, AtpI and AtpZ, based on comparison scores of up to 14.5 sds. A phylogenetic tree containing all of these proteins showed that the AtpZ proteins cluster coherently as a subset within the large and diverse AtpI cluster, which branches separately from the MCUs and IncAs, both of which cluster coherently. The MCUs and AtpZs share the same two TMS topology, but the AtpIs have four TMSs, and IncAs can have either two (most frequent) or four (less frequent) TMSs. Binary alignments, comparison scores and motif analyses showed that TMSs 1 and 2 align with TMSs 3 and 4 of the AtpIs, suggesting that the four TMS AtpI proteins arose via an intragenic duplication event. These findings establish an evolutionary link interconnecting eukaryotic and prokaryotic Ca(2+) and Mg(2+) transporters with chlamydial IncAs, and lead us to suggest that all members of the MCU superfamily, including IncAs, function as divalent cation channels.

  3. Establishing homology between mitochondrial calcium uniporters, prokaryotic magnesium channels and chlamydial IncA proteins

    PubMed Central

    Lee, Andre; Vastermark, Ake

    2014-01-01

    Mitochondrial calcium uniporters (MCUs) (TC no. 1.A.77) are oligomeric channel proteins found in the mitochondrial inner membrane. MCUs have two well-conserved transmembrane segments (TMSs), connected by a linker, similar to bacterial MCU homologues. These proteins and chlamydial IncA proteins (of unknown function; TC no. 9.B.159) are homologous to prokaryotic Mg2+ transporters, AtpI and AtpZ, based on comparison scores of up to 14.5 sds. A phylogenetic tree containing all of these proteins showed that the AtpZ proteins cluster coherently as a subset within the large and diverse AtpI cluster, which branches separately from the MCUs and IncAs, both of which cluster coherently. The MCUs and AtpZs share the same two TMS topology, but the AtpIs have four TMSs, and IncAs can have either two (most frequent) or four (less frequent) TMSs. Binary alignments, comparison scores and motif analyses showed that TMSs 1 and 2 align with TMSs 3 and 4 of the AtpIs, suggesting that the four TMS AtpI proteins arose via an intragenic duplication event. These findings establish an evolutionary link interconnecting eukaryotic and prokaryotic Ca2+ and Mg2+ transporters with chlamydial IncAs, and lead us to suggest that all members of the MCU superfamily, including IncAs, function as divalent cation channels. PMID:24869855

  4. Calcium

    MedlinePlus

    ... You'll also find calcium in broccoli and dark green, leafy vegetables (especially collard and turnip greens, ... can enjoy good sources of calcium such as dark green, leafy vegetables, broccoli, chickpeas, and calcium-fortified ...

  5. Effects of manganese, calcium, magnesium and zinc on nickel-induced suppression of murine natural killer cell activity

    SciTech Connect

    Smialowicz, R.J.; Rogers, R.R.; Riddle, M.M.; Luebke, R.W.; Fogelson, L.D.; Rowe, D.G.

    1987-01-01

    The effects that divalent metals have on nickel-induced suppression of natural killer (NK) cell activity were studied in mice. Male CBA/J mice were given a single intramuscular injection of the following: nickel chloride, 4.5-36 ..mu..g/g; manganese chloride, 20-80 ..mu..g/g; magnesium acetate, 50-200 ..mu..g/g; zinc acetate, 2-8 ..mu..g/g; or calcium acetate, 12.5-50 ..mu..g/g. Twenty-four hours after metal injection, splenic NK cell activity was assessed using a /sup 51/Cr-release assay. Ni significantly suppressed NK activity, while Mn significantly enhanced NK activity. No alteration in NK activity was observed in mice injected with Mg, Ca, or Zn. The injection of Ni and Mn in combination at a single site resulted in the enhancement of NK activity, although this enhancement was at a level below that observed following the injection of Mn alone. Injection of Mg, Zn, or Ca in combination with Ni did not affect NK activity compared to saline controls. In contrast, the injection of Ni in one thigh followed immediately by Mn, Mg, Ca, or Zn into the other thigh resulted in significant suppression of NK activity for all metals compared with saline controls. An interesting finding was that the injection of Ni followed immediately by Mn into the opposite thigh resulted in even greater reduction in NK activity than Ni alone. Suppression of NK activity by Ni and Mn injected at separate sites was not seen when Mn injection preceded Ni injection by 1 h.

  6. Evaluation of calcium and magnesium in scalp hair samples of population consuming different drinking water: risk of kidney stone.

    PubMed

    Panhwar, Abdul Haleem; Kazi, Tasneem Gul; Afridi, Hassan Imran; Shaikh, Haffeezur Rehman; Arain, Salma Aslam; Arain, Sadaf Sadia; Brahman, Kapil Dev

    2013-12-01

    The objective of this study was to examine the relationship between calcium (Ca) and magnesium (Mg) in underground water (UGW), bottled mineral water (BMW), and domestic treated water (DTW) with related to risk of kidney stones. The water samples were collected from different areas of Sindh, Pakistan. The scalp hair samples of both genders, age ranged 30-60 years, consuming different types of water, have or have not kidney disorders, were selected. The Ca and Mg concentrations were determined in scalp hair of study subjects and water by flame atomic absorption spectroscopy. The Ca and Mg contents in different types of drinking water, UGW, DTW, and BMW, were found in the range of 79.1-466, 23.7-140, and 45-270 mg/L and 4.43-125, 5.23-39.6, and 7.16-51.3 mg/L, respectively. It was observed that Ca concentration in the scalp hair samples of kidney stone patients consuming different types of drinking water was found to be higher (2,895-4721 μg/g) while Mg level (84.3-101 μg/g) was lower as compare to referents subjects (2,490-2,730 μg/g for Ca, 107-128 μg/g for Mg) in both genders. The positive correlation was found between Ca and Mg levels in water with related to kidney stone formations in population, especially who consumed underground water. A relative risk and odd ratio were calculated; the relative risk had a strong positive association with incidence of kidney stone which depends on types of drinking water.

  7. Equilibrium intakes of calcium and magnesium within an adequate and limited range of sodium intake in human.

    PubMed

    Nishimuta, Mamoru; Kodama, Naoko; Morikuni, Eiko; Yoshioka, Yayoi H; Matsuzaki, Nobue; Takeyama, Hidemaro; Yamada, Hideaki; Kitajima, Hideaki

    2006-12-01

    In the previous analysis of our human mineral balance studies, we demonstrated positive correlations between the balances of calcium (Ca) and magnesium (Mg) and sodium (Na) intake in the range of 3.06 and 4.06 g/d or 43.71 and 96.40 mg/kg body weight (BW)/d, but there was no correlation between Na intake and Na balance. This suggested that the balances of Ca and Mg are affected by Na intake. Therefore, in the current study, we recalculated equilibrium intakes for Ca and Mg when balances of their intakes and outputs were equal to zero within the above Na range to reduce the effects of Na intake. From 1986 to 2000, 90 volunteers (10 male, 80 female; age 18 to 28 y) took part in 9 mineral balance studies. The balance periods ranged from 8 to 12 d, with adaptation periods of 2 to 4 d. The dietary intakes of Ca and Mg ranged from 294 to 719 and 154 to 334 mg/d, or from 4.83 to 15.07 and 2.44 to 6.42 mg/kg BW/d, respectively. Intake of Ca significantly correlated with Ca balance (r2 = 0.268; p < 0.0001). When the balance was equal to zero, the mean value and upper limit of the 95% confidence interval for the regression equation between intake vs. balance were 10.072 and 10.660 mg/kg BW/d, respectively. Mg intake correlated significantly with Mg balance (r2 = 0.141, p = 0.003). When the balance was equal to zero, the mean value and upper limit of the 95% confidence interval for the regression equation between intake and balance were 4.078 and 4.287 mg/kg BW/d, respectively.

  8. Differential effects of zinc and magnesium ions on mineralization activity of phosphatidylserine calcium phosphate complexes.

    PubMed

    Wu, Licia N Y; Genge, Brian R; Wuthier, Roy E

    2009-07-01

    Mg(2+) and Zn(2+) are present in the mineral of matrix vesicles (MVs) and biological apatites, and are known to influence the onset and progression of mineral formation by amorphous calcium phosphate (ACP) and hydroxyapatite (HAP). However, neither has been studied systematically for its effect on mineral formation by phosphatidylserine-Ca(2+)-Pi complexes (PS-CPLX), an important constituent of the MV nucleation core. Presented here are studies on the effects of increasing levels of Mg(2+) and Zn(2+) on the process of mineral formation, either when present in synthetic cartilage lymph (SCL), or when incorporated during the formation of PS-CPLX. Pure HAP and PS-CPLX proved to be powerful nucleators, but ACP took much longer to induce mineral formation. In SCL, Mg(2+) and Zn(2+) had significantly different inhibitory effects on the onset and amount of mineral formation; HAP and PS-CPLX were less affected than ACP. Mg(2+) and Zn(2+) caused similar reductions in the rate and length of rapid mineral formation, but Zn(2+) was a more potent inhibitor on a molar basis. When incorporated into PS-CPLX, Mg(2+) and Zn(2+) caused significantly different effects than when present in SCL. Even low, subphysiological levels of Mg(2+) altered the inherent structure of PS-CPLX and markedly reduced its ability to induce and propagate mineral formation. Incorporated Zn(2+) caused significantly less effect, low (<20 microM) levels causing almost no inhibition. Levels of Zn(2+) present in MVs do not appear to inhibit their nucleational activity.

  9. Irrigation water acidification to neutralize alkalinity for nursery crop production: Substrate pH, electrical conductivity, and nutrient concentrations; and plant nutrition and growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Liming agents (LA) in irrigation water, typically associated with carbonates and bicarbonates of calcium (Ca) and magnesium (Mg), contribute to water alkalinity. Repeated application of LA to container crops can cause media-solution pH to rise overtime, that uncorrected, can lead to a nutrient avail...

  10. The Journal of Nutrition, Volume 106, 1976: Decreased absorption of calcium, magnesium, zinc and phosphorus by humans due to increased fiber and phosphorus consumption as wheat bread.

    PubMed

    Reinhold, J G; Faradji, B; Abadi, P; Ismail-Beigi, F

    1991-07-01

    During a 20 day period of high fiber consumption in the form of bread made partly from wheaten wholemeal, two men developed negative balances of calcium, magnesium, zinc and phosphorus due to increased fecal excretion of each element. The fecal losses correlated closely with fecal dry matter and phosphorus. Fecal dry matter, in turn, was directly proportional to fecal fiber excretion. Balances of nitrogen remained positive. Mineral elements were well-utilized by the same subjects during a 20 day period of white bread consumption.

  11. Diclofenac salts. III. Alkaline and earth alkaline salts.

    PubMed

    Fini, Adamo; Fazio, Giuseppe; Rosetti, Francesca; Angeles Holgado, M; Iruín, Ana; Alvarez-Fuentes, Josefa

    2005-11-01

    Diclofenac salts containing the alkaline and two earth alkaline cations have been prepared and characterized by scanning electron microscopy (SEM) and EDAX spectroscopy; and by thermal and thermogravimetric analysis (TGA): all of them crystallize as hydrate when precipitated from water. The salts dehydrate at room temperature and more easily on heating, but recovery the hydration, when placed in a humid environment. X-ray diffraction spectra suggest that on dehydration new peaks appear on diffractograms and the lattice of the salts partially looses crystallinity. This phenomenon is readily visible in the case of the calcium and magnesium salts, whose thermograms display a crystallization exotherm, before melting or decomposing at temperatures near or above 200 degrees C; these last salts appear to form solvates, when prepared from methanol. The thermogram of each salt shows a complex endotherm of dehydration about 100 degrees C; the calcium salt displays two endotherms, well separated at about 120 and 160 degrees C, which disappear after prolonged heating. Decomposition exotherms, before or soon after the melting, appear below 300 degrees C. The ammonium salt is thermally unstable and, when heated to start dehydration, dissociates and leaves acidic diclofenac.

  12. Predicting Gran alkalinity and calcium concentrations in river waters over a national scale using a novel modification to the G-BASH model.

    PubMed

    Cresser, Malcolm S; Ahmed, Nayan; Smart, Richard P; Arowolo, Toyin; Calver, Louise J; Chapman, Pippa J

    2006-09-01

    Monthly stream water calcium and Gran alkalinity concentration data from 11 sub-catchments of the Nether Beck in the English Lake District have been used to appraise the transferability of the Scottish, River Dee-based G-BASH model. Readily available riparian zone geochemistry and flow paths were used initially to predict minimum and mean stream water concentrations at the Nether Beck, based on calibration equations from the River Dee catchment data. Predicted values significantly exceeded observed values. Differences in runoff between the two areas, leading to a dilution effect in the Nether Beck, explained most of the difference between observed and predicted values. Greater acid deposition in the Lake District also reduced stream water Gran alkalinity concentrations in that area. If regional differences in precipitation, evapotranspiration and pollutant deposition are incorporated into the model, it may then be used reliably to predict catchment susceptibility to acidification over a wide regional (national) scale.

  13. Reference intervals of plasma calcium, phosphorus, and magnesium for African grey parrots (Psittacus erithacus) and Hispaniolan parrots (Amazona ventralis).

    PubMed

    de Carvalho, Fernanda M; Gaunt, Stephen D; Kearney, Michael T; Rich, Gregory A; Tully, Thomas N

    2009-12-01

    Calcium (Ca), phosphorus (P), and magnesium (Mg) are important elements for body homeostasis in several diseases associated with imbalances in the plasma concentration of these ions. This is the first published report of reference intervals for Mg in association with Ca and P levels for psittacine species. One milliliter of blood was collected from 26 Hispaniolan parrots (Amazona ventralis) and 24 African grey parrots (Psittacus erithacus). The plasma concentrations of Ca, P, and Mg were determined for each sample. Statistical analyses were performed including all data (analysis 1) and after exclusion of the subjects with Ca > or = 14.00 mg/dl (3.5 mmol) (analysis 2). The data from analysis 1 have a narrower interval than that observed in analysis 2. Following the normality test (Shapiro-Wilk, alpha = 0.05), the univariate and mean procedures were run. For the reference intervals, the lower and upper values were used, after elimination of the outliers calculated by Blom scores from the ranked variables. The analysis 1 references for the Hispaniolans were Ca = 8.80-10.40 mg/dl (2.20-2.60 mmol/L), P = 1.80-4.40 mg/dl (0.58-1.42 mmol/L), Mg = 1.80-3.10 mg/dl (0.74-1.27 mmol/L), and Ca:P ratio = 2.62-5.39; for the African greys analysis 1 references were Ca = 8.20-20.20 mg/dl (2.05-5.05 mmol/L), P = 2.50-5.90 mg/dl (0.81-1.91 mmol/L), Mg = 2.10-3.40 mg/dl (0.82-1.4 mmol/L), and Ca:P ratio = 1.81-3.77. The analysis 2 references for the Hispaniolans were Ca = 8.80-10.30 mg/dl (2.20-2.58 mmol/L), P = 1.80-3.80 mg/dl (0.58-1.23 mmol/L), Mg = 1.90-3.00 mg/dl (0.82-1.07 mmol/L), Ca:P ratio = 2.62-5.39; for the African greys analysis 2 references were Ca = 1.07 mmol/L), Ca:P ratio = 1.67-3.50. The results of this study are important for evaluating Mg concentrations in relation to the Ca and P parameters in psittacines. This information will be particularly helpful for veterinarians evaluating the hypocalcemic syndrome in African grey parrots and other disease processes

  14. Calcium-aluminum-rich inclusions with fractionation and unidentified nuclear effects (FUN CAIs): II. Heterogeneities of magnesium isotopes and 26Al in the early Solar System inferred from in situ high-precision magnesium-isotope measurements

    NASA Astrophysics Data System (ADS)

    Park, Changkun; Nagashima, Kazuhide; Krot, Alexander N.; Huss, Gary R.; Davis, Andrew M.; Bizzarro, Martin

    2017-03-01

    Calcium-aluminum-rich inclusions with isotopic mass fractionation effects and unidentified nuclear isotopic anomalies (FUN CAIs) have been studied for more than 40 years, but their origins remain enigmatic. Here we report in situ high precision measurements of aluminum-magnesium isotope systematics of FUN CAIs by secondary ion mass spectrometry (SIMS). Individual minerals were analyzed in six FUN CAIs from the oxidized CV3 carbonaceous chondrites Axtell (compact Type A CAI Axtell 2271) and Allende (Type B CAIs C1 and EK1-4-1, and forsterite-bearing Type B CAIs BG82DH8, CG-14, and TE). Most of these CAIs show evidence for excess 26Mg due to the decay of 26Al. The inferred initial 26Al/27Al ratios [(26Al/27Al)0] and the initial magnesium isotopic compositions (δ26Mg0) calculated using an exponential law with an exponent β of 0.5128 are (3.1 ± 1.6) × 10-6 and 0.60 ± 0.10‰ (Axtell 2271), (3.7 ± 1.5) × 10-6 and -0.20 ± 0.05‰ (BG82DH8), (2.2 ± 1.1) × 10-6 and -0.18 ± 0.05‰ (C1), (2.3 ± 2.4) × 10-5 and -2.23 ± 0.37‰ (EK1-4-1), (1.5 ± 1.1) × 10-5 and -0.42 ± 0.08‰ (CG-14), and (5.3 ± 0.9) × 10-5 and -0.05 ± 0.08‰ (TE) with 2σ uncertainties. We infer that FUN CAIs recorded heterogeneities of magnesium isotopes and 26Al in the CAI-forming region(s). Comparison of 26Al-26Mg systematics, stable isotope (oxygen, magnesium, calcium, and titanium) and trace element studies of FUN and non-FUN igneous CAIs indicates that there is a continuum among these CAI types. Based on these observations and evaporation experiments on CAI-like melts, we propose a generic scenario for the origin of igneous (FUN and non-FUN) CAIs: (i) condensation of isotopically normal solids in an 16O-rich gas of approximately solar composition; (ii) formation of CAI precursors by aggregation of these solids together with variable abundances of isotopically anomalous grains-possible carriers of unidentified nuclear (UN) effects; and (iii) melt evaporation of these precursors

  15. Novel biodegradable calcium phosphate/polymer composite coating with adjustable mechanical properties formed by hydrothermal process for corrosion protection of magnesium substrate.

    PubMed

    Kaabi Falahieh Asl, Sara; Nemeth, Sandor; Tan, Ming Jen

    2016-11-01

    Ceramic type coatings on metallic implants, such as calcium phosphate (Ca-P), are generally stiff and brittle, potentially leading to the early failure of the bone-implant interface. To reduce material brittleness, polyacrylic acid and carboxymethyl cellulose were used in this study to deposit two types of novel Ca-P/polymer composite coatings on AZ31 magnesium alloy using a one-step hydrothermal process. X-ray diffraction and scanning electron microscopy showed that the deposited Ca-P crystal phase and morphology could be controlled by the type and concentration of polymer used. Incorporation of polymer in the Ca-P coatings reduced the coating elastic modulus bringing it close to that of magnesium and that of human bone. Nanoindentation test results revealed significantly decreased cracking tendency with the incorporation of polymer in the Ca-P coating. Apart from mechanical improvements, the protective composite layers had also enhanced the corrosion resistance of the substrate by a factor of 1000 which is sufficient for implant application. Cell proliferation studies indicated that the composite coatings induced better cell attachment compared with the purely inorganic Ca-P coating, confirming that the obtained composite materials could be promising candidates for surface protection of magnesium for implant application with the multiple functions of corrosion protection, interfacial stress reduction, and cell attachment/cell growth promotion. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1643-1657, 2016.

  16. In Situ 13C NMR at Elevated-Pressures and -Temperatures Investigating the Conversion of CO2 to Magnesium and Calcium Carbonate Minerals

    NASA Astrophysics Data System (ADS)

    Surface, J. A.; Conradi, M. S.; Skemer, P. A.; Hayes, S. E.

    2013-12-01

    We have constructed specialized NMR hardware to conduct in situ elevated-pressure, elevated-temperature 13C NMR studies of unmixed heterogeneous mixtures of solids, liquids, gases, and supercritical fluids. Specifically, our aim is to monitor CO2 uptake in both ultramafic rocks and in more porous geological materials to understand the mechanisms of chemisorption as a function of temperature, pressure and pH. In this in situ NMR probe, we are able to simulate processes at geologically relevant fluid pressures and temperatures, monitoring the kinetics of CO2 conversion to carbonates. The in situ NMR experiments consist of heterogeneous mixtures of rock, salty brine solution, and moderate pressure CO2 gas at elevated temperatures. The purpose of studying these reactions is to determine efficacy of carbonate formation in various geological reservoirs. Via 13C NMR, we have spectroscopically characterized and quantified the conversion of CO2 to magnesium carbonate and calcium carbonate minerals. When CO2 reacts with the calcium or magnesium in a mineral or rock sample, the 13C chemical shift, linewidth, lineshape, and relaxation times change dramatically. This change can be monitored in situ and provide instantaneous and continuous characterization that maps the chemistry that is taking place. For example, on the pathway to MgCO3 formation, there are a number of phases of Mg(OH)x(H2O)y(CO3)z that are apparent via NMR spectroscopy. We will demonstrate that NMR can be used for quantitative characterization of multiple metastable mineral phases in pure forms and in mixtures. Results are confirmed via powder XRD and Raman spectroscopy of aquo- hydro- carbonato- magnesium species and calcium carbonate species. We also have monitored the 13C spectroscopy to analyze the phase of CO2 (liquid, supercritical, or gas) and its conversion into other forms, such as bicarbonate and carbonate species, providing a "window" into the in situ pH of the reacting system. Reference: 'In Situ

  17. Lead, cadmium, iron, zinc, copper, manganese, calcium and magnesium in SPF male rats exposed to a dilution of automotive exhaust gas throughout their lives.

    PubMed

    Stupfel, M; Valleron, A J; Radford, E

    1983-12-15

    Male pathogen free CFE albino Sprague Dawley rats were exposed 8 h per day, 5 days per week, for three years to a 1/1000 dilution of automotive exhaust gas, containing 58 ppm carbon monoxide, 0.37% carbon dioxide, 23 ppm nitrogen oxides, 2 ppm aldehydes, less than 5 mg/l hydrocarbons and 8.5 micrograms/m3 lead. Lead, cadmium, iron, zinc, calcium and magnesium were measured by atomic absorption in the femurs and tibias of the rats which died during the experiment. A comparison with two control groups revealed that the only significant difference in the elements measured in the bones was a 500% increase in lead concentration. The calculations of the correlations between the percentages of the elements in bones, the ages and the body weights of the rats, as well as cluster analysis, did not show consistent variations of the water, calcium, magnesium concentrations nor of the other studied metals related to this increase in lead concentration. Moreover, longevity was the same in the 3 groups of rats, but the body weight was statistically smaller (4%) in the group exposed to the auto exhaust dilution.

  18. Effect of different soaking solutions on nutritive utilization of minerals (calcium, phosphorus, and magnesium) from cooked beans (Phaseolus vulgaris L.) in growing rats.

    PubMed

    Nestares, Teresa; Barrionuevo, Mercedes; López-Frías, Magdalena; Vidal, Concepción; Urbano, Gloria

    2003-01-15

    The effects of the commonly used processing techniques of soaking (at different pH values) and cooking on the digestive and nutritive utilization of calcium, phosphorus, and magnesium from common beans (Phaseolus vulgaris L.) were studied. Before the cooking step, the beans were soaked in solutions of acid (2.6 and 5.3) or basic (8.4) pH. Chemical and biological methods were used to determine nutritional parameters in growing rats, and the fiber content of the beans was established. As the pH of the soaking solution increased, so did mineral absorption and the apparent digestibility coefficient, which reached suitable values for growing rats, due to the reduced losses of soluble minerals and the increased food intake. Metabolic utilization also improved with increased pH of the soaking solution, although the values were, in general, low as a result of urinary losses under the experimental conditions. For the experimental period of 10 days, the femur and the muscle seem to be good metabolic indicators for calcium, but not for phosphorus or magnesium. The increased amount of cellulose in the soaked seed did not have a negative effect on the digestive utilization of minerals.

  19. Bioavailability of iodine and hardness (magnesium and calcium salt) in drinking water in the etiology of endemic goitre in Sundarban delta of West Bengal (India).

    PubMed

    Chandra, Amar K; Tripathy, Smritiratan; Debnath, Arijit; Ghosh, Dishari

    2007-04-01

    Endemic goitre has been reported from the ecologically diverse Sundarban delta of West Bengal (India). To study the etiological factors for the persistence of endemic goitre, bioavailability of iodine and hardness of water used for drinking in the region were evaluated because these common environmental factors are inversely and directly related with goitre prevalence in several geographical regions. For the present study from 19 Community Development Blocks of Sundarban delta, 19 areas were selected at random. From each area at least 8 drinking water samples were collected and analyzed for iodine and the hardness (calcium and magnesium salt content). Iodine content in the drinking water samples was found in the range from 21 to 119 mg/L and total hardness of drinking water was found to range from 50 to 480 ppm. Presence of magnesium salt was found higher than the calcium salts in most of the samples. These findings suggest that the entire delta region is environmentally iodine sufficient but water is relatively hard and thus possibility of hardness of water for the persistence of endemic goitre may not be ruled out.

  20. A comparison of the effects of glucose ingestion and NH4Cl acidosis on urinary calcium and magnesium excretion in man

    PubMed Central

    Lennon, Edward J.; Piering, Walter F.

    1970-01-01

    Both glucose ingestion and NH4Cl acidosis have been reported to augment urinary calcium (UCa V) and magnesium (UMg V) excretion. Both also cause acidification of the urine and an increase in renal acid excretion. To examine whether a common mechanism of action was involved, the effects of glucose ingestion and NH4Cl acidosis on UCa V and UMg V were tested in the same subjects. Glucose ingestion caused significant increases in both UCa V and UMg V. During stable NH4Cl acidosis, UCa V increased significantly, while UMg V was unaffected. When a glucose load was given during acidosis, the separate effects of acidosis and glucose on UCa V were additive, whereas UMg V increased less than observed during normal acid-base balance. Although renal acid excretion increased and the urine was acidified after glucose in the normal steady state, when glucose was administered during NH4Cl acidosis urine pH rose and there was no change in renal acid excretion. We concluded that NH4Cl acidosis and glucose ingestion reduce the renal tubular reabsorption of magnesium and (or) calcium, but they act through separate mechanisms. PMID:5432375

  1. Promotion of in vivo degradability, vascularization and osteogenesis of calcium sulfate-based bone cements containing nanoporous lithium doping magnesium silicate

    PubMed Central

    Cao, Liehu; Weng, Weizong; Chen, Xiao; Zhang, Jun; Zhou, Qirong; Cui, Jin; Zhao, Yuechao; Shin, Jung-Woog; Su, Jiacan

    2017-01-01

    Nanoporous lithium doping magnesium silicate (nl-MS) was introduced into calcium sulfate hemihydrate to prepare calcium sulfate composite (nl-MSC) bone cements. The introduction of nl-MS improved the in vitro degradability of nl-MSC cements, which could neutralize acidic degradable products of calcium sulfate and prevented the pH from dropping. The cements were implanted into the bone defects of femur bone of rabbits, and the results of histological and immunohistochemical analysis revealed that massive new bone tissue formed in the defects while the cements were degradable, indicating that the osteogenesis and degradability of the nl-MSC cements were much better than the control calcium sulfate dihydrate (CSD) cements. Furthermore, the positive expression of vascular endothelial growth factor and collagen type I for nl-MSC cements was higher than CSD, indicating that addition of nl-MS into the cements enhanced vascularization and osteogenic differentiation. The results suggested that the nl-MSC cements with good biocompatibility and degradability could promote vascularization and osteogenesis, and had great potential to treat bone defects. PMID:28260883

  2. Deleterious effects of magnesium intoxication upon the domestic broiler chick

    SciTech Connect

    Lee, S.R.

    1984-01-01

    Dietary levels of 0.6 to 0.8% magnesium in a corn-soy basal were rachitogenic. These rickets appeared most like phosphorus deficiency. Bone Ca/P ratios were numerically quite low implying a lack of transformation from amorphous calcium phosphate to hydroxyapatite. Bone alkaline phosphatase activity was elevated. Additional dietary phosphorus ameliorated, but could not overcome the rachitogenic effects of magnesium. Tibial dyschondroplasia (TD), induced by elevated dietary P, was decreased by high levels of dietary Mg, but with no decrease in plasma phosphorus. Anticoccidial ionophores fed in conjunction with a moderate dietary challenge of Mg (0.48%) produced no clear changes in plasma calcium or Mg, but did interact to reduce body weight. The diarrhea caused by magnesium intoxication is not due to hyperosmotic loads of Mg per se. Rather, Cl was observed to be the major ionic constituent of the gut osmotic load implying different gut ionic fluxes in control versus magnesium intoxicated chicks. These data imply that the cathartic action of Mg is due to hypersecretion of the gut. Effects mediated or modified by the CNS changed in magnesium intoxicated chicks. Such chicks appeared cold and stayed near the heat. When startled, they exhibited extreme avoidance behavior and seizures similar to epilepsy and/or Cl deficiency. Brain tissue Mg content did not concomitantly increase. Whether these effects are due to central signals is unclear.

  3. Calcium, Magnesium, and Phosphorus Metabolism, and Parathyroid- Calcitonin Function during Prolonged Exposure to Elevated CO2 Concentrations on Submarines

    DTIC Science & Technology

    1975-12-01

    blood Pco * and bicarbonate. Urinary calcium excretion decreased again during the 5th to 8th week, with a secondary decrease in blood pH and plasma...analyzed in the laboratory. *P =s 0.05. CALCIUM METABOLISM DURING SUBMARINE PATROL S61 three weeks of exposure, followed by a secondary increase in Pco ...G. Nichols, Jr., and R. H. Wasserman, Eds. Some implications in cellular mechanisms for calcium transfer and homeostasis . Academic Press, New York

  4. What We Eat In America, NHANES 2005-2006, usual nutrient intakes from food and water compared to 1997 Dietary Reference Intakes for vitamin D, calcium, phosphorus, and magnesium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This report presents national estimates of usual nutrient intake distributions from food and water for vitamin D, calcium, phosphorus, and magnesium and compares those estimates to the Dietary Reference Intakes published by the Institute of Medicine in 1997. Estimates are based on data from 8,437 in...

  5. Effects of phosphates on microstructure and bioactivity of micro-arc oxidized calcium phosphate coatings on Mg-Zn-Zr magnesium alloy.

    PubMed

    Pan, Y K; Chen, C Z; Wang, D G; Zhao, T G

    2013-09-01

    Calcium phosphate (CaP) coatings were prepared on Mg-Zn-Zr magnesium alloy by micro-arc oxidation (MAO) in electrolyte containing calcium acetate monohydrate (CH3COO)2Ca·H2O) and different phosphates (i.e. disodium hydrogen phosphate dodecahydrate (Na2HPO4·12H2O), sodium phosphate (Na3PO4·H2O) and sodium hexametaphosphate((NaPO3)6)). Scanning electron microscope (SEM), energy-dispersive X-ray spectrometry (EDS) and X-ray diffractometer (XRD) were employed to characterize the microstructure, elemental distribution and phase composition of the CaP coatings. Simulated body fluid (SBF) immersion test was used to evaluate the coating bioactivity and degradability. Systemic toxicity test was used to evaluate the coating biocompatibility. Fluoride ion selective electrode (ISE) was used to measure F(-) ions concentration during 30 days SBF immersion. The CaP coatings effectively reduced the corrosion rate and the surfaces of CaP coatings were covered by a new layer formed of numerous needle-like and scale-like apatites. The formation of these calcium phosphate apatites indicates that the coatings have excellent bioactivity. The coatings formed in (NaPO3)6-containging electrolyte exhibit thicker thickness, higher adhesive strength, slower degradation rate, better apatite-inducing ability and biocompatibility.

  6. Reported Dietary Intake, Disparity between the Reported Consumption and the Level Needed for Adequacy and Food Sources of Calcium, Phosphorus, Magnesium and Vitamin D in the Spanish Population: Findings from the ANIBES Study †.

    PubMed

    Olza, Josune; Aranceta-Bartrina, Javier; González-Gross, Marcela; Ortega, Rosa M; Serra-Majem, Lluis; Varela-Moreiras, Gregorio; Gil, Ángel

    2017-02-21

    Calcium, phosphorus, magnesium and vitamin D have important biological roles in the body, especially in bone metabolism. We aimed to study the reported intake, the disparity between the reported consumption and the level needed for adequacy and food sources of these four nutrients in the Spanish population. We assessed the reported intake for both, general population and plausible reporters. Results were extracted from the ANIBES survey, n = 2009. Three-day dietary reported intake data were obtained and misreporting was assessed according to the European Food Safety Authority (EFSA). Mean ± SEM (range) total reported consumption of calcium, phosphorus, magnesium, and vitamin D for the whole population were 698 ± 7 mg/day (71-2551 mg/day), 1176 ± 8 mg/day, (331-4429 mg/day), 222 ± 2 mg/day (73-782 mg/day), and 4.4 ± 0.1 µg/day (0.0-74.2 µg/day), respectively. In the whole group, 76% and 66%; 79% and 72%; and 94% and 93% of the population had reported intakes below 80% of the national and European recommended daily intakes for calcium, magnesium and vitamin D, respectively; these percentages were over 40% when the plausible reporters were analysed separately. The main food sources were milk and dairy products for calcium and phosphorus, cereals and grains for magnesium and fish for vitamin D. In conclusion, there is an important percentage of the Spanish ANIBES population not meeting the recommended intakes for calcium, magnesium and vitamin D.

  7. Reported Dietary Intake, Disparity between the Reported Consumption and the Level Needed for Adequacy and Food Sources of Calcium, Phosphorus, Magnesium and Vitamin D in the Spanish Population: Findings from the ANIBES Study †

    PubMed Central

    Olza, Josune; Aranceta-Bartrina, Javier; González-Gross, Marcela; Ortega, Rosa M.; Serra-Majem, Lluis; Varela-Moreiras, Gregorio; Gil, Ángel

    2017-01-01

    Calcium, phosphorus, magnesium and vitamin D have important biological roles in the body, especially in bone metabolism. We aimed to study the reported intake, the disparity between the reported consumption and the level needed for adequacy and food sources of these four nutrients in the Spanish population. We assessed the reported intake for both, general population and plausible reporters. Results were extracted from the ANIBES survey, n = 2009. Three-day dietary reported intake data were obtained and misreporting was assessed according to the European Food Safety Authority (EFSA). Mean ± SEM (range) total reported consumption of calcium, phosphorus, magnesium, and vitamin D for the whole population were 698 ± 7 mg/day (71–2551 mg/day), 1176 ± 8 mg/day, (331–4429 mg/day), 222 ± 2 mg/day (73–782 mg/day), and 4.4 ± 0.1 µg/day (0.0–74.2 µg/day), respectively. In the whole group, 76% and 66%; 79% and 72%; and 94% and 93% of the population had reported intakes below 80% of the national and European recommended daily intakes for calcium, magnesium and vitamin D, respectively; these percentages were over 40% when the plausible reporters were analysed separately. The main food sources were milk and dairy products for calcium and phosphorus, cereals and grains for magnesium and fish for vitamin D. In conclusion, there is an important percentage of the Spanish ANIBES population not meeting the recommended intakes for calcium, magnesium and vitamin D. PMID:28230782

  8. The content of fluoride, calcium and magnesium in the hair of young men of the Bantu language group from Tanzania versus social conditioning.

    PubMed

    Rębacz-Maron, Ewa; Baranowska-Bosiacka, Irena; Gutowska, Izabela; Krzywania, Natalia; Chlubek, Dariusz

    2013-12-01

    The present study aimed at analysing the content of fluorine (F), calcium (Ca) and magnesium (Mg) in the hair of young male students (n =52) of a secondary school in Mafinga in Tanzania (Africa) who participated in anthropological examinations. Ca and Mg concentrations were determined using atomic absorption spectrophotometer while F levels using a potentiometric method. F in the hair of boys from older group (≥16 years old; n =24) was significantly higher than in the younger group (<16 years old; n =28) versus Ca and Mg levels. High carbohydrate diet was predominant- mainly based on corn or bean and meat served once a week, with few fruit and raw vegetables. Collective catering in the dormitory reflected habits and culinary preferences at home. The lack of balanced diet, with majority of the nutritional energy supplied by easily accessible and cheap carbohydrates, was reflected in dietary deficiencies, characterised, among others, by visible skin conditions and tooth decay.

  9. Determination of ammonium, calcium, magnesium, potassium and sodium in drinking waters by capillary zone electrophoresis on a column-coupling chip.

    PubMed

    Masár, Marián; Sydes, Daniel; Luc, Milan; Kaniansky, Dusan; Kuss, Heinz-Martin

    2009-08-21

    This work deals with simultaneous determination of ammonium, calcium, magnesium, sodium and potassium in drinking waters by capillary zone electrophoresis (CZE) on a column-coupling (CC) chip with suppressed hydrodynamic and electroosmotic transports. CZE separations were carried out in a propionate background electrolyte at a low pH (3.2) containing 18-crown-6-ether (18-crown-6) to reach a complete resolution of the cations. In addition, triethylenetetramine (TETA) coated the inner wall surface of the chip channels. The concentration limits of detection (cLOD) for the studied cations ranged from 4.9 to 11.5 microg/l concentrations using a 900 nl volume of the sample injection channel. 93-106% recoveries of the cations in drinking waters indicate a good predisposition of the present method to provide accurate analytical results.

  10. Absorption of calcium, magnesium, phosphorus, iron and zinc in growing male rats fed diets containing either phytate-free soybean protein or soybean protein isolate or casein.

    PubMed

    Kamao, M; Tsugawa, N; Nakagawa, K; Kawamoto, Y; Fukui, K; Takamatsu, K; Kuwata, G; Imai, M; Okano, T

    2000-02-01

    The effect of dietary phytate-free soybean protein (PFS) on intestinal mineral absorption and retention was examined in growing male rats using a three-day mineral balance technique. The rats were fed diets containing PFS, soybean protein isolate (SPI) or casein at a 20% level for 5 wk. Total calcium (Ca), magnesium (Mg), phosphorus (P), iron (Fe) and zinc (Zn) contents in diets were adjusted to 0.35, 0.05, 0.7, 0.0035 and 0.003%, respectively, by supplementation of the diet with their salts. Mineral absorption and retention ratios in rats fed the PFS diet were significantly higher than those in rats fed either the SPI or casein diet. These results suggest that PFS may be a promising dietary protein source for improving the mineral bioavailability in humans.

  11. Alkaline flocculation of Phaeodactylum tricornutum induced by brucite and calcite

    DOE PAGES

    Vandamme, Dries; Pohl, Philip I.; Beuckels, Annelies; ...

    2015-08-20

    Alkaline flocculation holds great potential as a low-cost harvesting method for marine microalgae biomass production. Alkaline flocculation is induced by an increase in pH and is related to precipitation of calcium and magnesium salts. In this study, we used the diatom Phaeodactylum tricornutum as model organism to study alkaline flocculation of marine microalgae cultured in seawater medium. Flocculation started when pH was increased to 10 and flocculation efficiency reached 90% when pH was 10.5, which was consistent with precipitation modeling for brucite or Mg(OH)2. Compared to freshwater species, more magnesium is needed to achieve flocculation (>7.5 mM). Zeta potential measurementsmore » suggest that brucite precipitation caused flocculation by charge neutralization. When calcium concentration was 12.5 mM, flocculation was also observed at a pH of 10. Furthermore, zeta potential remained negative up to pH 11.5, suggesting that precipitated calcite caused flocculation by a sweeping coagulation mechanism.« less

  12. Magnesium: Is It a Viable Option?

    DTIC Science & Technology

    2012-08-01

    strike - High alkalinityMagnesium strike – High alkalinity • Electroless Nickel - formulated to prevent attach of magnesium. Success Stories...ionic palladium, palladium reducer, electroless copper and electroless nickel. The initial results were encouraging: We were able to Get the parts

  13. Low pressure ion chromatography with a low cost paired emitter-detector diode based detector for the determination of alkaline earth metals in water samples.

    PubMed

    Barron, Leon; Nesterenko, Pavel N; Diamond, Dermot; O'Toole, Martina; Lau, King Tong; Paull, Brett

    2006-09-01

    The use of a low pressure ion chromatograph based upon short (25 mm x 4.6 mm) surfactant coated monolithic columns and a low cost paired emitter-detector diode (PEDD) based detector, for the determination of alkaline earth metals in aqueous matrices is presented. The system was applied to the separation of magnesium, calcium, strontium and barium in less than 7min using a 0.15M KCl mobile phase at pH 3, with post-column reaction detection at 570 nm using o-cresolphthalein complexone. A comparison of the performance of the PEDD detector with a standard laboratory absorbance detector is shown, with limits of detection for magnesium and calcium using the low cost PEDD detector equal to 0.16 and 0.23 mg L(-1), respectively. Finally, the developed system was used for the determination of calcium and magnesium in a commercial spring water sample.

  14. Calcium, magnesium, and phosphorus metabolism, and parathyroid-calcitonin function during prolonged exposure to elevated CO2 concentrations on submarines.

    PubMed

    Messier, A A; Heyder, E; Braithwaite, W R; McCluggage, C; Peck, A; Schaefer, K E

    1979-01-01

    Studies of calcium and phosphorus metabolism and acid-base balance were carried out on three Fleet Ballistic Missile (FBM) submarines during prolonged exposure to elevated concentrations of CO2. The average CO2 concentration in the submarine atmosphere during patrols ranged from 0.85% to 1% CO2. In the three studies, in which 9--15 subjects participated, the urinary excretion of calcium and phosphate fell during the first three weeks to a level commensurate with a decrease in plasma calcium and increase in phosphorus. In the fourth week of one patrol, a marked increase was found in urinary calcium excretion, associated with a rise in blood PCO2 and bicarbonate. Urinary calcium excretion decreased again during the 5th to 8th week, with a secondary decrease in blood pH and plasma calcium. During the third patrol, the time course of acid-base changes corresponded well with that found during the second patrol. There was a trend toward an increase in plasma calcium between the fourth and fifth week commensurate with the transient rise in pH and bicarbonate. Plasma parathyroid and calcitonin hormone activities were measured in two patrols and no significant changes were found. Hydroxyproline excretion decreased in the three-week study and remained unchanged in the second patrol, which lasted 57 days. It is suggested that during prolonged exposure to low levels of CO2 (up to 1% CO2), calcium metabolism is controlled by the uptake and release of CO2 in the bones. The resulting phases in bone buffering, rather than renal regulation, determine acid-base balance.

  15. 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 ...

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

    PubMed

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

    2011-12-01

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

  17. Pore water chemistry of an alkaline rift valley lake: Lake Turkana, Kenya

    SciTech Connect

    Cerling, T.E.; Johnson, T.C.; Halfman, J.D.; Lister, G.

    1985-01-01

    Lake Turkana is the largest closed basin lake in the African rift system. It has evolved through the past 5000 years to become a moderately alkaline lake. Previous mass balance argument suggest that sulfate is removed from the lake by sulfate reduction in the sediments, and that the lake is accumulating in chloride, sodium, and alkalinity. Studies of pore water from 12 meter cores collected in November 1984 show that sulfate is reduced in the sediment column with a net production of alkalinity. Some sodium is lost from the lake and diffuses into the sediment to maintain charge balance. At several meters depth, organic matter is destroyed by methanogenic bacteria, as shown by the high delta /sup 13/C values for dissolved inorganic carbon. Magnesium and calcium molar ratios change with depth; chloride, sodium, and alkalinity also change with depth.

  18. Reversible Coordination of Boron-, Aluminum-, Zinc-, Magnesium-, and Calcium-Hydrogen Bonds to Bent {CuL2} Fragments: Heavy σ Complexes of the Lightest Coinage Metal.

    PubMed

    Hicken, Alexandra; White, Andrew J P; Crimmin, Mark R

    2017-03-22

    A series of copper(I) complexes bearing electron-deficient β-diketiminate ligands have been prepared. The study includes [{{ArNC(CR3)}2CH}Cu(η(2)-toluene)n] (Ar = Mes, R = F, n = 0.5, [12·tol]; Ar = C6F5, R = Me, n = 1, [2·tol]; Ar = 2,6-Cl2C6H3, R = H, n = 0.5, [32·tol]). Reactions of [1-3n·tol] with boranes, alanes, a zinc hydride, a magnesium hydride, and a calcium hydride generate the corresponding σ complexes ([1-3·B], [3·B'], [3·Al], [3·Al'], [1-3·Zn], [1·Mg], and [1·Ca]). These species all form reversibly, being in equilibrium with the arene solvates in solution. With the exception of the calcium complex, the complexes have all been characterized by single-crystal X-ray diffraction studies. In solution, the σ-hydride of the aluminum, zinc, magnesium, and calcium derivatives resonates between -0.12 and -1.77 ppm (C6D6 or toluene-d8, 193-298 K). For the σ-borane complexes, the hydrides are observed as a single resonance between 2 and 3.5 ppm (C6D6, 298 K) and bridging and terminal hydrides rapidly exchange on the NMR time scale even at 193 K. Quantification of the solution dynamics by van't Hoff analysis yields expectedly small values of ΔH° and negative values of ΔS° consistent with weak binding and a reversible process that does not involve aggregation of the copper species. The donor-acceptor complexes can be rationalized in terms of the Dewar-Chatt-Duncanson model. Density functional theory calculations show that the donation of σ-M-H (or E-H) electrons into the 4s-based orbital (LUMO or LUMO+1) of the copper fragment is accompanied by weak back-donation from a dxz-based orbital (HOMO or HOMO-1) into the σ*-M-H (or E-H) orbital.

  19. The influence of dietary palmitic acid triacylglyceride position on the fatty acid, calcium and magnesium contents of at term newborn faeces.

    PubMed

    López-López, A; Castellote-Bargalló, A I; Campoy-Folgoso, C; Rivero-Urgël, M; Tormo-Carnicé, R; Infante-Pina, D; López-Sabater, M C

    2001-11-01

    The distribution of long-chain saturated fatty acids in triglycerides is different in infant formulas to that in human milk. In human milk, palmitic acid is predominantly esterified in the sn-2 position (beta-position) of the triglycerides, whereas in infant formulas, it is esterified mainly in the sn-1,3 positions (alpha,alpha'-positions). The specific distribution of the fatty acids in the triglyceride plays a key role in lipid digestion and absorption. We studied fatty-acid, calcium and magnesium composition in the faeces of three groups of at term newborn infants fed different diets: Group A (n=12) was fed from birth to 2 months with human milk (66% palmitic acid in beta-position), Group B (n=12) was fed with formula alpha (19% palmitic acid esterified in beta-position) for 2 months, and Group C (n=12) was fed with formula alpha during the first month and with formula beta (44.5% palmitic acid in beta-position) during the second month. Samples were taken at the end of the first month (t0) and at the end of the second month (t1). Groups A and C presented significantly lower contents of palmitic acid in faeces at t1 than at t0, whereas in Group B, amounts remained similar. Faecal calcium in Groups A and C decreased in the second month (t1), although the fall was no statistically significant. In Group B, calcium amounts showed no change. We found that infant formula beta when compared with infant formula alpha reduced significantly the contents of total fatty acids and palmitic acid in faeces. We conclude that palmitic acid in beta-position is, therefore, beneficial for term infants.

  20. Magnesium alloys and graphite wastes encapsulated in cementitious materials: Reduction of galvanic corrosion using alkali hydroxide activated blast furnace slag.

    PubMed

    Chartier, D; Muzeau, B; Stefan, L; Sanchez-Canet, J; Monguillon, C

    2017-03-15

    Magnesium alloys and graphite from spent nuclear fuel have been stored together in La Hague plant. The packaging of these wastes is under consideration. These wastes could be mixed in a grout composed of industrially available cement (Portland, calcium aluminate…). Within the alkaline pore solution of these matrixes, magnesium alloys are imperfectly protected by a layer of Brucite resulting in a slow corrosion releasing hydrogen. As the production of this gas must be considered for the storage safety, and the quality of wasteform, it is important to select a cement matrix capable of lowering the corrosion kinetics. Many types of calcium based cements have been tested and most of them have caused strong hydrogen production when magnesium alloys and graphite are conditioned together because of galvanic corrosion. Exceptions are binders based on alkali hydroxide activated ground granulated blast furnace slag (BFS) which are presented in this article.

  1. Effect of magnesium/calcium ratio in solutions subjected to electrodialysis: characterization of cation-exchange membrane fouling.

    PubMed

    Casademont, Christophe; Pourcelly, Gérald; Bazinet, Laurent

    2007-11-15

    Electrodialysis is based on the migration of charged species through perm-selective membranes under an electric field. Fouling, which is the accumulation of undesired solid materials at the interfaces of these membranes, is one of the major problems of this process. The aim of the present work was to investigate the nature and the morphology of fouling observed at different Mg/Ca ratios (R=0, 1/20, 1/10, 1/5, 2/5) on cation-exchange membranes (CEM) during conventional electrodialysis treatments. It appeared that for R=0, the fouling observed on the surface in contact with the basified concentrate was formed of only Ca(OH)2. As soon as magnesium was introduced into the solution treated, CaCO3 was observed. Furthermore, the X-ray diffraction results also identified the CaCO3 observed as calcite. To our knowledge, this is the first time that the presence of magnesium has been demonstrated to induce a CaCO3 fouling on CEM during electrodialysis.

  2. Identifying calcium sources at an acid deposition-impacted spruce forest: A strontium isotope, alkaline earth element multi-tracer approach

    USGS Publications Warehouse

    Bullen, T.D.; Bailey, S.W.

    2005-01-01

    Depletion of calcium from forest soils has important implications for forest productivity and health. Ca is available to fine feeder roots from a number of soil organic and mineral sources, but identifying the primary source or changes of sources in response to environmental change is problematic. We used strontium isotope and alkaline earth element concentration ratios of trees and soils to discern the record of Ca sources for red spruce at a base-poor, acid deposition-impacted watershed. We measured 87Sr/86Sr and chemical compositions of cross-sectional stemwood cores of red spruce, other spruce tissues and sequential extracts of co-located soil samples. 87Sr/86Sr and Sr/Ba ratios together provide a tracer of alkaline earth element sources that distinguishes the plant-available fraction of the shallow organic soils from those of deeper organic and mineral soils. Ca/Sr ratios proved less diagnostic, due to within-tree processes that fractionate these elements from each other. Over the growth period from 1870 to 1960, 87Sr/86Sr and Sr/Ba ratios of stemwood samples became progressively more variable and on average trended toward values that considered together are characteristic of the uppermost forest floor. In detail the stemwood chemistry revealed an episode of simultaneous enhanced uptake of all alkaline earth elements during the growth period from 1930 to 1960, coincident with reported local and regional increases in atmospheric inputs of inorganic acidity. We attribute the temporal trends in stemwood chemistry to progressive shallowing of the effective depth of alkaline earth element uptake by fine roots over this growth period, due to preferential concentration of fine roots in the upper forest floor coupled with reduced nutrient uptake by roots in the lower organic and upper mineral soils in response to acid-induced aluminum toxicity. Although both increased atmospheric deposition and selective weathering of Ca-rich minerals such as apatite provide possible

  3. Magnesium prevents β-glycerophosphate-induced calcification in rat aortic vascular smooth muscle cells.

    PubMed

    Bai, Yaling; Zhang, Junxia; Xu, Jinsheng; Cui, Liwen; Zhang, Huiran; Zhang, Shenglei; Feng, Xunwei

    2015-07-01

    Vascular calcification (VC), in which high serum phosphate plays a critical role, is one major problem in patients with chronic kidney disease. Clinical studies report that magnesium has a protective effect on VC. However, the studies regarding the impact of high serum magnesium on VC at a cellular level are few and require further investigation. Therefore, the present study explored the effect of magnesium on calcification induced by β-glycerophosphate (BGP) in rat aortic vascular smooth muscle cells (RAVSMCs). In the present study, the addition of magnesium decreased calcium deposition, which was increased by BGP. Higher magnesium levels inhibited BGP-induced alkaline phosphatase (ALP) activity and decreased the expression of core-binding factor α-1 (Cbfα1). In conclusion, higher magnesium levels prevented BGP-induced calcification in RAVSMCs and inhibited the expression of Cbfα1 and ALP. Thus, magnesium is influencing the expression of Cbfα1 and ALP associated with VC and may have the potential to serve as a role for VC in clinical situations.

  4. Magnesium modification up-regulates the bioactivity of bone morphogenetic protein-2 upon calcium phosphate cement via enhanced BMP receptor recognition and Smad signaling pathway.

    PubMed

    Ding, Sai; Zhang, Jing; Tian, Yu; Huang, Baolin; Yuan, Yuan; Liu, Changsheng

    2016-09-01

    Efficient presentation of growth factors is one of the great challenges in tissue engineering. In living systems, bioactive factors exist in soluble as well as in matrix-bound forms, both of which play an integral role in regulating cell behaviors. Herein, effect of magnesium on osteogenic bioactivity of recombinant human bone morphogenetic protein-2 (rhBMP-2) was investigated systematically with a series of Mg modified calcium phosphate cements (xMCPCs, x means the content of magnesium phosphate cement wt%) as matrix model. The results indicated that the MCPC, especially 5MCPC, could promote the rhBMP-2-induced in vitro osteogenic differentiation via Smad signaling of C2C12 cells. Further studies demonstrated that all MCPC substrates exhibited similar rhBMP-2 release rate and preserved comparable conformation and biological activity of the released rhBMP-2. Also, the ionic extracts of MCPC made little difference to the bioactivity of rhBMP-2, either in soluble or in matrix-bound forms. However, with the quartz crystal microbalance (QCM), we observed a noticeable enhancement of rhBMP-2 mass-uptake on 5MCPC as well as a better recognition of the bound rhBMP-2 to BMPR IA and BMPR II. In vivo results demonstrated a better bone regeneration capacity of 5MCPC/rhBMP-2. From the above, our results demonstrated that it was the Mg anchored on the underlying substrates that tailored the way of rhBMP-2 bound on MCPC, and thus facilitated the recognition of BMPRs to stimulate osteogenic differentiation. The study will guide the development of Mg-doped bioactive bone implants for tissue regeneration.

  5. Novel injectable, self-gelling hydrogel-microparticle composites for bone regeneration consisting of gellan gum and calcium and magnesium carbonate microparticles.

    PubMed

    Douglas, Timothy E L; Łapa, Agata; Reczyńska, Katarzyna; Krok-Borkowicz, Małgorzata; Pietryga, Krzysztof; Samal, Sangram Keshari; Declercq, Heidi A; Schaubroeck, David; Boone, Marijn; Van der Voort, Pascal; De Schamphelaere, Karel; Stevens, Christian V; Bliznuk, Vitaliy; Balcaen, Lieve; Parakhonskiy, Bogdan V; Vanhaecke, Frank; Cnudde, Veerle; Pamuła, Elżbieta; Skirtach, Andre G

    2016-11-21

    The suitability of hydrogel biomaterials for bone regeneration can be improved by incorporation of an inorganic phase in particle form, thus maintaining hydrogel injectability. In this study, carbonate microparticles containing different amounts of calcium (Ca) and magnesium (Mg) were added to solutions of the anionic polysaccharide gellan gum (GG) to crosslink GG by release of Ca(2+) and Mg(2+) from microparticles and thereby induce formation of hydrogel-microparticle composites. It was hypothesized that increasing Mg content of microparticles would promote GG hydrogel formation. The effect of Mg incorporation on cytocompatibility and cell growth was also studied. Microparticles were formed by mixing Ca(2+) and Mg(2+) and [Formula: see text] ions in varying concentrations. Microparticles were characterized physiochemically and subsequently mixed with GG solution to form hydrogel-microparticle composites. The elemental Ca:Mg ratio in the mineral formed was similar to the Ca:Mg ratio of the ions added. In the absence of Mg, vaterite was formed. At low Mg content, magnesian calcite was formed. Increasing the Mg content further caused formation of amorphous mineral. Microparticles of vaterite and magnesium calcite did not induce GG hydrogel formation, but addition of Mg-richer amorphous microparticles induced gelation within 20 min. Microparticles were dispersed homogeneously in hydrogels. MG-63 osteoblast-like cells were cultured in eluate from hydrogel-microparticle composites and on the composites themselves. All composites were cytocompatible. Cell growth was highest on composites containing particles with an equimolar Ca:Mg ratio. In summary, carbonate microparticles containing a sufficient amount of Mg induced GG hydrogel formation, resulting in injectable, cytocompatible hydrogel-microparticle composites.

  6. The Influence of Fe Substitution in Lanthanum Calcium Cobalt Oxide on the Oxygen Evolution Reaction in Alkaline Media

    DOE PAGES

    Abreu-Sepulveda, Maria A.; Dhital, Chetan; Huq, Ashfia; ...

    2016-07-30

    The effect due to systematic substitution of cobalt by iron in La0.6Ca0.4Co1-xFexO3 towards the oxygen evolution reaction(OER) in alkaline media has been investigated. We synthesized these compounds by a facile glycine-nitrate synthesis and the phase formation was confirmed by X-ray diffraction and Neutron Diffraction elemental analysis. The apparent OER activity was evaluated by quasi steady state current measurements in alkaline media using a traditional three-electrode cell. X-ray photoelectron spectroscopy shows iron substitution causes an increase in the surface concentration of various cobalt oxidation states. Tafel slope in the vicinity of 60 mV/decade and electrochemical reaction order towards OH- near unitymore » were achieved for the unsubstituted La0.6Ca0.4CoO3. Moreover, a decrease in the Tafel slope to 49 mV/decade was observed when iron is substituted in high amounts in the perovskite structure. The area specific current density showed dependence on the Fe fraction, however the relationship of specific current density with Fe fraction is not linear. High Fe substitutions, La0.6Ca0.4Co0.2Fe0.8O3 and La0.6Ca0.4Co0.1Fe0.9O3 showed higher area specific activity towards OER than La0.6Ca0.4CoO3 or La0.6Ca0.4FeO3. Finally, we believe iron inclusion in the cobalt sites of the perovskite helps decrease the electron transfer barrier and facilitates the formation of cobalt-hydroxide at the surface. Possible OER mechanisms based on the observed kinetic parameters will be discussed.« less

  7. A CALPHAD study on the thermodynamic stability of calcium-, zinc-, and yttrium-doped magnesium in aqueous environments

    SciTech Connect

    Wu, Kaisheng; Dogan, Omar N.; Velikokhatnyl, Oleg I.; Kumta, Prashant N.

    2011-12-15

    Magnesium has attracted the attention of the biomaterials community as a potential biodegradable metallic candidate for use in stents and orthopedic applications. Alloying of Mg with metals such as Ca, Y and Zn, etc., to form alloy precursors is important to optimize its corrosion rate in electrolytic and aqueous environments to understand the alloy response in body fluid environments. In the current study, the chemical reactions of Mg–Me alloys (Me = Ca, Y, and Zn) with pure water have been investigated using the CALPHAD technique. A qualitative agreement between CALPHAD and first-principles results has been obtained. The CALPHAD method has also been employed to study the reactions of Mg alloys in the human blood fluid environment. The effects of alloying elements and compositions on the reaction enthalpies, reaction products, amount of gas release and gas compositions as well as the pH of the fluids have been systematically discussed and reported.

  8. A CALPHAD Study on the Thermodynamic Stability of Calcium-, Zinc-, and Yttrium-Doped Magnesium in Aqueous Environments

    SciTech Connect

    Wu, Kaisheng

    2011-12-15

    Magnesium has attracted the attention of the biomaterials community as a potential biodegradable metallic candidate for use in stents and orthopedic applications. Alloying of Mg with metals such as Ca, Y and Zn, etc., to form alloy precursors is important to optimize its corrosion rate in electrolytic and aqueous environments to understand the alloy response in body fluid environments. In the current study, the chemical reactions of Mg–Me alloys (Me = Ca, Y, and Zn) with pure water have been investigated using the CALPHAD technique. A qualitative agreement between CALPHAD and first-principles results has been obtained. The CALPHAD method has also been employed to study the reactions of Mg alloys in the human blood fluid environment. The effects of alloying elements and compositions on the reaction enthalpies, reaction products, amount of gas release and gas compositions as well as the pH of the fluids have been systematically discussed and reported.

  9. Involvement of oxygen free radicals in the respiratory uncoupling induced by free calcium and ADP-magnesium in isolated cardiac mitochondria: comparing reoxygenation in cultured cardiomyocytes.

    PubMed

    Meynier, Alexandra; Razik, Hafida; Cordelet, Catherine; Grégoire, Stéphane; Demaison, Luc

    2003-01-01

    Recently, we have observed that the simultaneous application of free calcium (fCa) and ADP-magnesium (Mg) reduced the ADP:O ratio in isolated cardiac mitochondria. The uncoupling was prevented by cyclosporin A, an inhibitor of the permeability transition pore. The purpose of this study was to know if the generation of oxygen free radicals (OFR) is involved in this phenomenon and if it occurs during reoxygenation (Reox) of cultured cardiomyocytes. Cardiac mitochondria were harvested from male Wistar rats. Respiration was assessed in two media with different fCa concentrations (0 or 0.6 microM) with palmitoylcarnitine and ADP-Mg as respiration substrates. The production of Krebs cycle intermediates (KCI) was determined. Without fCa in the medium, the mitochondria displayed a large production of citrate + isocitrate + alpha-ketoglutarate. fCa drastically reduced these KCI and promoted the accumulation of succinate. To know if OFR are involved in the respiratory uncoupling, the effect of 4OH-TEMPO (250 microM), a hydrosoluble scavenger of OFR, was tested. 4OH-TEMPO completely abolished the fCa- and ADP-Mg-induced uncoupling. Conversely, vitamin E contributed to further decreasing the ADP:O ratio. Since no hydrosoluble electron acceptor was added in our experiment, the oxygen free radical-induced oxidized vitamin E was confined near the mitochondrial membranes, which should reduce the ADP:O ratio by opening the permeability transition pore. The generation of OFR could result from the matrix accumulation of succinate. Taken together, these results indicate that mitochondrial Ca uptake induces a slight increase in membrane permeability. Thereafter, Mg enters the matrix and, in combination with Ca, stimulates the isocitrate and/or alpha-ketoglutarate dehydrogenases. Matrix succinate favors oxygen free radical generation that further increases membrane permeability and allows respiratory uncoupling through proton leakage. To determine whether the phenomenon takes place

  10. The Influence of Fe Substitution in Lanthanum Calcium Cobalt Oxide on the Oxygen Evolution Reaction in Alkaline Media

    SciTech Connect

    Abreu-Sepulveda, Maria A.; Dhital, Chetan; Huq, Ashfia; Li, Ling; Bridges, Craig A.; Paranthaman, M. Parans; Narayanan, S. R.; Quesnel, David J.; Tryk, Donald A.; Manivannan, A.

    2016-07-30

    The effect due to systematic substitution of cobalt by iron in La0.6Ca0.4Co1-xFexO3 towards the oxygen evolution reaction(OER) in alkaline media has been investigated. We synthesized these compounds by a facile glycine-nitrate synthesis and the phase formation was confirmed by X-ray diffraction and Neutron Diffraction elemental analysis. The apparent OER activity was evaluated by quasi steady state current measurements in alkaline media using a traditional three-electrode cell. X-ray photoelectron spectroscopy shows iron substitution causes an increase in the surface concentration of various cobalt oxidation states. Tafel slope in the vicinity of 60 mV/decade and electrochemical reaction order towards OH- near unity were achieved for the unsubstituted La0.6Ca0.4CoO3. Moreover, a decrease in the Tafel slope to 49 mV/decade was observed when iron is substituted in high amounts in the perovskite structure. The area specific current density showed dependence on the Fe fraction, however the relationship of specific current density with Fe fraction is not linear. High Fe substitutions, La0.6Ca0.4Co0.2Fe0.8O3 and La0.6Ca0.4Co0.1Fe0.9O3 showed higher area specific activity towards OER than La0.6Ca0.4CoO3 or La0.6Ca0.4FeO3. Finally, we believe iron inclusion in the cobalt sites of the perovskite helps decrease the electron transfer barrier and facilitates the formation of cobalt-hydroxide at the surface. Possible OER mechanisms based on the observed kinetic parameters will be discussed.

  11. Investigation on the thermo-chemical reaction mechanism between yttria-stabilized zirconia (YSZ) and calcium-magnesium-alumino-silicate (CMAS)

    NASA Astrophysics Data System (ADS)

    Zhang, Dong-Bo; Wang, Bin-Yi; Cao, Jian; Song, Guan-Yu; Liu, Juan-Bo

    2015-03-01

    Thermal barrier coatings (TBCs) with Y2O3-stabilized ZrO2 (YSZ) top coat play a very important role in advanced turbine blades by considerably increasing the engine efficiency and improving the performance of highly loaded blades. However, at high temperatures, environment factors result in the failure of TBCs. The influence of calcium-magnesium-alumino-silicate (CMAS) is one of environment factors. Although thermo-physical effect is being paid attention to, the thermo-chemical reaction becomes the hot-spot in the research area of TBCs affected by CMAS. In this paper, traditional twolayered structured TBCs were prepared by electron beam physical vapor deposition (EBPVD) as the object of study. TBCs coated with CMAS were heated at 1240°C for 3 h. Additionally, 15 wt.% simulated molten CMAS powder and YSZ powder were mixed and heated at 1240°C or 1350°C for 48 h. SEM and EDS were adopted to detect morphology and elements distribution. According to XRD and TEM results, it was revealed that CMAS react with YSZ at high temperature and form ZrSiO4, Ca0.2Zr0.8O1.8 and Ca0.15Zr0.85O1.85 after reaction, as a result, leading to the failure of TBCs and decreasing the TBC lifetime.

  12. Biofortification of crops with seven mineral elements often lacking in human diets--iron, zinc, copper, calcium, magnesium, selenium and iodine.

    PubMed

    White, Philip J; Broadley, Martin R

    2009-01-01

    The diets of over two-thirds of the world's population lack one or more essential mineral elements. This can be remedied through dietary diversification, mineral supplementation, food fortification, or increasing the concentrations and/or bioavailability of mineral elements in produce (biofortification). This article reviews aspects of soil science, plant physiology and genetics underpinning crop biofortification strategies, as well as agronomic and genetic approaches currently taken to biofortify food crops with the mineral elements most commonly lacking in human diets: iron (Fe), zinc (Zn), copper (Cu), calcium (Ca), magnesium (Mg), iodine (I) and selenium (Se). Two complementary approaches have been successfully adopted to increase the concentrations of bioavailable mineral elements in food crops. First, agronomic approaches optimizing the application of mineral fertilizers and/or improving the solubilization and mobilization of mineral elements in the soil have been implemented. Secondly, crops have been developed with: increased abilities to acquire mineral elements and accumulate them in edible tissues; increased concentrations of 'promoter' substances, such as ascorbate, beta-carotene and cysteine-rich polypeptides which stimulate the absorption of essential mineral elements by the gut; and reduced concentrations of 'antinutrients', such as oxalate, polyphenolics or phytate, which interfere with their absorption. These approaches are addressing mineral malnutrition in humans globally.

  13. Method development for the determination of calcium, copper, magnesium, manganese, iron, potassium, phosphorus and zinc in different types of breads by microwave induced plasma-atomic emission spectrometry.

    PubMed

    Ozbek, Nil; Akman, Suleyman

    2016-06-01

    A novel method was developed for the determination of calcium, magnesium, potassium, iron, copper, zinc, and manganese and phosphorous in various kinds of breads samples sold in Turkey by microwave plasma-atomic emission spectrometry (MIP-AES). Breads were dried at 100 °C for one day, ground thoroughly and then digested using nitric acid/hydrogen per oxide (3:1). The analytes in certified reference wheat flour and maize flour samples were determined in the uncertainty limits of the certified values as well as the analytes added to the mixture of ground bread and acid mixture prior to digestion were recovered quantitatively (>90%). Therefore, all determinations were made by linear calibration technique using aqueous standards. The LOD values for Ca, Cu, Fe, K, Mg, Mn, P and Zn were 13.1, 0.28, 4.47, 118, 1.10, 0.41, 7550 and 3.00 ng mL(-1), respectively. No spectral interference was detected at the working wavelengths of the analytes.

  14. Effects of Calcium and Magnesium Ions on Acute Copper Toxicity to Glochidia and Early Juveniles of the Chinese Pond Mussel Anodonta woodiana.

    PubMed

    Liu, Hongbo; Chen, Xiubao; Su, Yanping; Kang, Ik Joon; Qiu, Xuchun; Shimasaki, Yohei; Oshima, Yuji; Yang, Jian

    2016-10-01

    We evaluated the effects of calcium (Ca(2+)) and magnesium (Mg(2+)) ions on copper (Cu) toxicity to glochidia and newly-transformed juvenile mussels (age 1-2 days) of the Chinese pond mussel (Anodonta woodiana). Acute Cu toxicity tests were performed with glochidia for 24 h and juveniles for 96 h with measured Ca(2+) concentrations of 1.1, 14, 26, 51, and 99 mg L(-1), or measured Mg(2+) concentrations of 2.6, 11, 21, and 39 mg L(-1). The Ca(2+) and Mg(2+) cations provided no statistically significant protection against Cu toxicity to glochidia or juveniles. The 24-h EC50 value for glochidia was 82 μg L(-1) Cu, and contrastly, 96-h EC50 value for newly-transformed juvenile mussels was as low as 12 μg L(-1) Cu, implying that the juveniles of A. woodiana are more vulnerable to Cu contamination at concentrations close to currently-accepted levels.

  15. Effects of calcium magnesium acetate on the combustion of coal-water slurries. Final project report, 1 September 1989--28 February 1993

    SciTech Connect

    Levendis, Y.A.; Wise, D.; Metghalchi, H.; Cumper, J.; Atal, A.; Estrada, K.R.; Murphy, B.; Steciak, J.; Hottel, H.C.; Simons, G.

    1993-07-01

    To conduct studies on the combustion of coal water fuels (CWFs) an appropriate facility was designed and constructed. The main components were (1) a high-temperature isothermal laminar flow furnace that facilitates observation of combustion events in its interior. The design of this system and its characterization are described in Chapter 1. (2) Apparatus for slurry droplet/agglomerate particle generation and introduction in the furnace. These devices are described in Chapters 1 and 3 and other attached publications. (3) An electronic optical pyrometer whose design, construction theory of operation, calibration and performance are presented in Chapter 2. (4) A multitude of other accessories, such as particle fluidization devices, a suction thermometer, a velocimeter, high speed photographic equipment, calibration devices for the pyrometer, etc., are described throughout this report. Results on the combustion of CWF droplets and CWF agglomerates made from micronized coal are described in Chapter 3. In the same chapter the combustion of CWF containing dissolved calcium magnesium acetate (CMA) axe described. The combustion behavior of pre-dried CWF agglomerates of pulverized grain coal is contrasted to that of agglomerates of micronized coal in Chapter 4. In the same chapter the combustion of agglomerates of carbon black and diesel soot is discussed as well. The effect of CMA on the combustion of the above materials is also discussed. Finally, the sulfur capture capability of CMA impregnated micronized and pulverized bituminous coals is examined in Chapter 5.

  16. Calcium-phosphate biomineralization induced by alkaline phosphatase activity in Escherichia coli: localization, kinetics and potential signatures in the fossil record

    NASA Astrophysics Data System (ADS)

    Cosmidis, Julie; Benzerara, Karim; Guyot, François; Skouri-Panet, Fériel; Duprat, Elodie; Férard, Céline; Guigner, Jean-Michel; Babonneau, Florence; Coelho, Cristina

    2015-12-01

    Bacteria are thought to play an important role in the formation of calcium-phosphate minerals composing marine phosphorites, as supported by the common occurrence of fossil microbes in these rocks. Phosphatase enzymes may play a key role in this process. Indeed, they may increase the supersaturation with respect to Ca-phosphates by releasing orthophosphate ions following hydrolysis of organic phosphorus. However, several questions remain unanswered about the cellular-level mechanisms involved in this model, and its potential signatures in the mineral products. We studied Ca-phosphate precipitation by different strains of Escherichia coli which were genetically modified to differ in the abundance and cellular localization of the alkaline phosphatase (PHO A) produced. The mineral precipitated by either E. coli or purified PHO A was invariably identified as a carbonate-free non-stoichiometric hydroxyapatite. However, the bacterial precipitates could be discriminated from the ones formed by purified PHO A at the nano-scale. PHO A localization was shown to influence the pattern of Ca-phosphate nucleation and growth. Finally, the rate of calcification was proved to be consistent with the PHO A enzyme kinetics. Overall, this study provides mechanistic keys to better understand phosphogenesis in the environment, and experimental references to better interpret the microbial fossil record in phosphorites.

  17. Surface integrity and process mechanics of laser shock peening of novel biodegradable magnesium-calcium (Mg-Ca) alloy.

    PubMed

    Sealy, M P; Guo, Y B

    2010-10-01

    Current permanent metallic biomaterials of orthopedic implants, such as titanium, stainless steel, and cobalt-chromium alloys, have excellent corrosive properties and superior strengths. However, their strengths are often too high resulting in a stress shielding effect that is detrimental to the bone healing process. Without proper healing, costly and painful revision surgeries may be required. The close Young's modulus between magnesium-based implants and cancellous bones has the potential to minimize stress shielding while providing both biocompatibility and adequate mechanical properties. The problem with Mg implants is how to control corrosion rates so that the degradation of Mg implants matches that of bone growth. Laser shock peening (LSP) is an innovative surface treatment method to impart compressive residual stress to a novel Mg-Ca implant. The high compressive residual stress has great potential to slow corrosion rates. Therefore, LSP was initiated in this study to investigate surface topography and integrity produced by sequential peening a Mg-Ca alloy. Also, a 3D semi-infinite simulation was developed to predict the topography and residual stress fields produced by sequential peening. The dynamic mechanical behavior of the biomaterial was modeled using a user material subroutine from the internal state variable plasticity model. The temporal and spatial peening pressure was modeled using a user load subroutine. The simulated dent agrees with the measured dent topography in terms of profile and depth. Sequential peening was found to increase the tensile pile-up region which is critical to orthopedic applications. The predicted residual stress profiles are also presented.

  18. Calcium and Magnesium Ions Are Membrane-Active against Stationary-Phase Staphylococcus aureus with High Specificity.

    PubMed

    Xie, Yuntao; Yang, Lihua

    2016-02-11

    Staphylococcus aureus (S. aureus) is notorious for its ability to acquire antibiotic-resistance, and antibiotic-resistant S. aureus has become a wide-spread cause of high mortality rate. Novel antimicrobials capable of eradicating S. aureus cells including antibiotic-resistant ones are thus highly desired. Membrane-active bactericides and species-specific antimicrobials are two promising sources of novel anti-infective agents for fighting against bacterial antibiotic-resistance. We herein show that Ca(2+) and Mg(2+), two alkaline-earth-metal ions physiologically essential for diverse living organisms, both disrupt model S. aureus membranes and kill stationary-phase S. aureus cells, indicative of membrane-activity. In contrast to S. aureus, Escherichia coli and Bacillus subtilis exhibit unaffected survival after similar treatment with these two cations, indicative of species-specific activity against S. aureus. Moreover, neither Ca(2+) nor Mg(2+) lyses mouse red blood cells, indicative of hemo-compatibility. This works suggests that Ca(2+) and Mg(2+) may have implications in targeted eradication of S. aureus pathogen including the antibiotic-resistant ones.

  19. Calcium and Magnesium Ions Are Membrane-Active against Stationary-Phase Staphylococcus aureus with High Specificity

    PubMed Central

    Xie, Yuntao; Yang, Lihua

    2016-01-01

    Staphylococcus aureus (S. aureus) is notorious for its ability to acquire antibiotic-resistance, and antibiotic-resistant S. aureus has become a wide-spread cause of high mortality rate. Novel antimicrobials capable of eradicating S. aureus cells including antibiotic-resistant ones are thus highly desired. Membrane-active bactericides and species-specific antimicrobials are two promising sources of novel anti-infective agents for fighting against bacterial antibiotic-resistance. We herein show that Ca2+ and Mg2+, two alkaline-earth-metal ions physiologically essential for diverse living organisms, both disrupt model S. aureus membranes and kill stationary-phase S. aureus cells, indicative of membrane-activity. In contrast to S. aureus, Escherichia coli and Bacillus subtilis exhibit unaffected survival after similar treatment with these two cations, indicative of species-specific activity against S. aureus. Moreover, neither Ca2+ nor Mg2+ lyses mouse red blood cells, indicative of hemo-compatibility. This works suggests that Ca2+ and Mg2+ may have implications in targeted eradication of S. aureus pathogen including the antibiotic-resistant ones. PMID:26865182

  20. Calcium and Magnesium Ions Are Membrane-Active against Stationary-Phase Staphylococcus aureus with High Specificity

    NASA Astrophysics Data System (ADS)

    Xie, Yuntao; Yang, Lihua

    2016-02-01

    Staphylococcus aureus (S. aureus) is notorious for its ability to acquire antibiotic-resistance, and antibiotic-resistant S. aureus has become a wide-spread cause of high mortality rate. Novel antimicrobials capable of eradicating S. aureus cells including antibiotic-resistant ones are thus highly desired. Membrane-active bactericides and species-specific antimicrobials are two promising sources of novel anti-infective agents for fighting against bacterial antibiotic-resistance. We herein show that Ca2+ and Mg2+, two alkaline-earth-metal ions physiologically essential for diverse living organisms, both disrupt model S. aureus membranes and kill stationary-phase S. aureus cells, indicative of membrane-activity. In contrast to S. aureus, Escherichia coli and Bacillus subtilis exhibit unaffected survival after similar treatment with these two cations, indicative of species-specific activity against S. aureus. Moreover, neither Ca2+ nor Mg2+ lyses mouse red blood cells, indicative of hemo-compatibility. This works suggests that Ca2+ and Mg2+ may have implications in targeted eradication of S. aureus pathogen including the antibiotic-resistant ones.

  1. Magnesium modulates the expression levels of calcification-associated factors to inhibit calcification in a time-dependent manner.

    PubMed

    Xu, Jinsheng; Bai, Yaling; Jin, Jingjing; Zhang, Junxia; Zhang, Shenglei; Cui, Liwen; Zhang, Huiran

    2015-03-01

    Vascular calcification, a common complication in patients with chronic kidney disease, involves a variety of mechanisms associated with the regulation of calcification-associated factors. Previous clinical studies have indicated that magnesium is involved in the reduction of vascular calcification; however, the mechanism underlying this process remains unknown. The aim of the present study was to investigate the effects of magnesium on β-glycerophosphate (β-GP)-induced calcification and the underlying mechanisms. Primary rat vascular smooth muscle cells (VSMCs) were exposed to 10 mM β-GP in medium with or without the addition of 3 mM magnesium or 2-aminoethoxy-diphenylborate (2-APB; an inhibitor of magnesium transport), for a 14-day period. Calcium deposition and alkaline phosphatase (ALP) activity were measured by Alizarin red staining, quantification of calcium and enzyme-linked immunosorbent assay. The expression levels of core-binding factor α-1 (Cbfα1), matrix Gla protein (MGP) and osteopontin (OPN) were determined by reverse transcription-polymerase chain reaction or western blot analysis, following incubation for 0, 3, 6, 10 and 14 days with the different media. VSMC calcification and ALP activity was reduced significantly in the high-magnesium medium compared with the calcification medium, during the 14-day incubation. The magnesium-induced changes in the VSMCs included a β-GP-induced downregulation of Cbfα1 by day 3 of incubation, an effect that was gradually enhanced over the 14-day period. By contrast, magnesium produced notable increases in MGP and OPN expression levels, with an opposite pattern to that observed in the Cbfα1 expression levels. However, the addition of 2-APB appeared to inhibit the protective effect of magnesium on the VSMCs. Therefore, magnesium was able to effectively reduce β-GP-induced calcification in rat VSMCs by regulating the expression levels of calcification-associated factors in a time-dependent manner.

  2. [Automated method for determining calcium in biological liquids].

    PubMed

    Duchassaing, D; Ekindjian, O G; Leluan, G

    1977-01-01

    A method of determination of calcium in biological fluids is proposed. It is a continuous flow technic without deproteinisation nor dialysis, using orthocresol phtaleine in alkaline medium. The interference due to magnesium is eliminated by the presence of hydroxy-8-quinoleine. The addition of dimethyl sulfoxide improves the solubility of the reagents and ensures better stability of the media. The correlation between the results obtained by this technic and by atomic absorption spectrophotometry was studied on 160 human sera and 40 urines. The influence of various parameters such as hemolysis, bilirubin, magnesium and phosphates is low or negligeable. The results concerning opalescent, cloudy or lactescent sera may be erroneous by excess. The physiological reference values for serum calcium are drawn up from a Paris student population of both sexes.

  3. Magnesium basics

    PubMed Central

    Ketteler, Markus

    2012-01-01

    As a cofactor in numerous enzymatic reactions, magnesium fulfils various intracellular physiological functions. Thus, imbalance in magnesium status—primarily hypomagnesaemia as it is seen more often than hypermagnesaemia—might result in unwanted neuromuscular, cardiac or nervous disorders. Measuring total serum magnesium is a feasible and affordable way to monitor changes in magnesium status, although it does not necessarily reflect total body magnesium content. The following review focuses on the natural occurrence of magnesium and its physiological function. The absorption and excretion of magnesium as well as hypo- and hypermagnesaemia will be addressed. PMID:26069819

  4. Investigation of magnesium-zinc-calcium alloys and bone marrow derived mesenchymal stem cell response in direct culture.

    PubMed

    Cipriano, Aaron F; Sallee, Amy; Guan, Ren-Guo; Zhao, Zhan-Yong; Tayoba, Myla; Sanchez, Jorge; Liu, Huinan

    2015-01-01

    Crystalline Mg-Zn-Ca ternary alloys have recently attracted significant interest for biomedical implant applications due to their promising biocompatibility, bioactivity, biodegradability and mechanical properties. The objective of this study was to characterize as-cast Mg-xZn-0.5Ca (x=0.5, 1.0, 2.0, 4.0wt.%) alloys, and determine the adhesion and morphology of bone marrow derived mesenchymal stem cells (BMSCs) at the interface with the Mg-xZn-0.5Ca alloys. The direct culture method (i.e. seeding cells directly onto the surface of the sample) was established in this study to probe the highly dynamic cell-substrate interface and thus to elucidate the mechanisms of BMSC responses to dynamic alloy degradation. The results showed that the BMSC adhesion density on these alloys was similar to the cell-only positive control and the BMSC morphology appeared more anisotropic on the rapidly degrading alloy surfaces in comparison with the cell-only positive control. Importantly, neither culture media supplemented with up to 27.6mM Mg(2+) ions nor media intentionally adjusted up to alkaline pH 9 induced any detectable adverse effects on BMSC responses. We speculated that degradation-induced dynamic surface topography played an important role in modulating cell morphology at the interface. This study presents a clinically relevant in vitro model for screening bioresorbable alloys, and provides useful design guidelines for determining the degradation rate of implants made of Mg-Zn-Ca alloys.

  5. Crystallization of calcium sulfate dihydrate under simulated conditions of phosphoric acid production in the presence of aluminum and magnesium ions

    NASA Astrophysics Data System (ADS)

    Rashad, M. M.; Mahmoud, M. H. H.; Ibrahim, I. A.; Abdel-Aal, E. A.

    2004-06-01

    The effect of Al 3+ and Mg 2+ ions, as additives, on the crystallization of gypsum was studied under simulated conditions of the phosphoric acid production. Calcium hydrogen phosphate and sulfuric acid were mixed with dilute phosphoric acid at 80°C, and the turbidity of the reaction mixture was measured at different time periods to calculate the induction time of gypsum crystals formation. Addition of Al 3+ ions up to 2% decreased the induction time and increased the growth efficiency while addition of Mg 2+ increased the induction time and decreased the growth efficiency compared with in absence of additives. Interestingly, the crystals mean and median diameters were found to increase in the presence of Al 3+ and decrease in the presence of Mg 2+. The surface energy increased with Al 3+ and decreased with Mg 2+ compared to the baseline (without additives). Gypsum morphology changed from needle-like type in absence of additives to thick-rhombic in the presence of Al 3+ ions.

  6. Osteogenic evaluation of calcium/magnesium-doped mesoporous silica scaffold with incorporation of rhBMP-2 by synchrotron radiation-based μCT.

    PubMed

    Dai, Chenglong; Guo, Han; Lu, Jingxiong; Shi, Jianlin; Wei, Jie; Liu, Changsheng

    2011-11-01

    The regenerative treatment of large osseous defects remains a formidable challenge in orthopedic surgery today. In the present study, we have synthesized biodegradable calcium/magnesium-doped silica-based scaffolds with hierarchically macro/mesoporous structure (CMMS), and incorporated recombinant human bone morphogenetic protein-2 (rhBMP-2) into the scaffolds to obtain a hybrid system for osteogenic factor delivery in the functional repair of bone defects. The developed CMMS/rhBMP-2 scaffolds presented interconnected porous network, macropores (200-500 μm) and mesopores (5.7 nm), as well as good bioactivity and biocompatibility and proper degradation rate. Combined with the capacity to deliver ions and growth factors, the CMMS/rhBMP-2 scaffolds significantly promoted the in vitro osteogenic differentiation of bone marrow stromal cells (bMSCs), as evidenced by the enhanced expression of Runx-2, osteopontin, osteocalcin and bone sialoprotein, and induced the ectopic bone formation in the thigh muscle pouches of mice. We further assessed the in vivo effects of CMMS/rhBMP-2 scaffolds in a rabbit femur cavity defect model by using synchrotron radiation-based μCT (SRμCT) imaging and histological analysis, indicating that the CMMS/rhBMP-2 scaffolds resulted in more bone regeneration compared to that observed with the CMMS scaffolds without rhBMP-2. Moreover, scaffolds with or without rhBMP-2 underwent gradual resorption and replacement with bone and almost disappeared at 12 weeks, while the dense CMMS/rhBMP-2 material showed slower degradation rate and promoted the least extensive neo-bone formation. This study suggested that the hybrid CMMS/rhBMP-2 scaffolds system demonstrates promise for bone regeneration in clinical case of large bone defects.

  7. Evidence for Cross-Tolerance to Nutrient Deficiency in Three Disjunct Populations of Arabidopsis lyrata ssp. lyrata in Response to Substrate Calcium to Magnesium Ratio

    PubMed Central

    Veatch-Blohm, Maren E.; Roche, Bernadette M.; Campbell, MaryJean

    2013-01-01

    Species with widespread distributions that grow in varied habitats may consist of ecotypes adapted to a particular habitat, or may exhibit cross-tolerance that enables them to exploit a variety of habitats. Populations of Arabidopsis lyrata ssp. lyrata (L.) O’Kane & Al-Shehbaz grow in a wide variety of edaphic settings including serpentine soil, limestone sand, and alluvial flood plains. While all three of these environments share some stressors, a crucial difference among these environments is soil calcium to magnesium ratio, which ranges from 25∶1 in the limestone sand to 0.2∶1 in serpentine soil. The three populations found on these substrates were subjected to three different Ca to Mg ratios under controlled environmental conditions during germination and rosette growth. Response to Ca to Mg ratio was evaluated through germination success and radicle growth rate, rosette growth rate, and the content of Ca and Mg in the rosette. All three populations were particularly efficient in fueling growth under nutrient deficiency, with the highest nutrient efficiency ratio for Ca under Ca deficiency and for Mg under Mg deficiency. Although the serpentine population had significantly higher leaf Ca to Mg ratio than the limestone or flood plain populations under all three Ca to Mg ratios, this increase did not result in any advantage in growth or appearance of the serpentine plants, during early life stages before the onset of flowering, even in the high Mg substrate. The three populations showed no population by substrate interaction for any of the parameters measured indicating that these populations may have cross-tolerance to substrate Ca to Mg ratio. PMID:23650547

  8. The effects of secular calcium and magnesium concentration changes on the thermodynamics of seawater acid/base chemistry: Implications for Eocene and Cretaceous ocean carbon chemistry and buffering

    NASA Astrophysics Data System (ADS)

    Hain, Mathis P.; Sigman, Daniel M.; Higgins, John A.; Haug, Gerald H.

    2015-05-01

    Reconstructed changes in seawater calcium and magnesium concentration ([Ca2+], [Mg2+]) predictably affect the ocean's acid/base and carbon chemistry. Yet inaccurate formulations of chemical equilibrium "constants" are currently in use to account for these changes. Here we develop an efficient implementation of the MIAMI Ionic Interaction Model to predict all chemical equilibrium constants required for carbon chemistry calculations under variable [Ca2+] and [Mg2+]. We investigate the impact of [Ca2+] and [Mg2+] on the relationships among the ocean's pH, CO2, dissolved inorganic carbon (DIC), saturation state of CaCO3 (Ω), and buffer capacity. Increasing [Ca2+] and/or [Mg2+] enhances "ion pairing," which increases seawater buffering by increasing the concentration ratio of total to "free" (uncomplexed) carbonate ion. An increase in [Ca2+], however, also causes a decline in carbonate ion to maintain a given Ω, thereby overwhelming the ion pairing effect and decreasing seawater buffering. Given the reconstructions of Eocene [Ca2+] and [Mg2+] ([Ca2+]~20 mM; [Mg2+]~30 mM), Eocene seawater would have required essentially the same DIC as today to simultaneously explain a similar-to-modern Ω and the estimated Eocene atmospheric CO2 of ~1000 ppm. During the Cretaceous, at ~4 times modern [Ca2+], ocean buffering would have been at a minimum. Overall, during times of high seawater [Ca2+], CaCO3 saturation, pH, and atmospheric CO2 were more susceptible to perturbations of the global carbon cycle. For example, given both Eocene and Cretaceous seawater [Ca2+] and [Mg2+], a doubling of atmospheric CO2 would require less carbon addition to the ocean/atmosphere system than under modern seawater composition. Moreover, increasing seawater buffering since the Cretaceous may have been a driver of evolution by raising energetic demands of biologically controlled calcification and CO2 concentration mechanisms that aid photosynthesis.

  9. NASA's Advanced Environmental Barrier Coatings Development for SiC/SiC Ceramic Matrix Composites: Understanding Calcium Magnesium Alumino-Silicate (CMAS) Degradations and Resistance

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming

    2014-01-01

    Environmental barrier coatings (EBCs) and SiCSiC ceramic matrix composites (CMCs) systems will play a crucial role in next generation turbine engines for hot-section component applications because of their ability to significantly increase engine operating temperatures with improved efficiency, reduce engine weight and cooling requirements. The development of prime-reliant environmental barrier coatings is essential to the viability and reliability of the envisioned CMC engine component applications, ensuring integrated EBC-CMC system durability and designs are achievable for successful applications of the game-changing component technologies and lifing methodologies.This paper will emphasize recent NASA environmental barrier coating developments for SiCSiC turbine airfoil components, utilizing advanced coating compositions, state-of-the-art processing methods, and combined mechanical and environment testing and durability evaluations. The coating-CMC degradations in the engine fatigue-creep and operating environments are particularly complex; one of the important coating development aspects is to better understand engine environmental interactions and coating life debits, and we have particularly addressed the effect of Calcium-Magnesium-Alumino-Silicate (CMAS) from road sand or volcano-ash deposits on the durability of the environmental barrier coating systems, and how the temperature capability, stability and cyclic life of the candidate rare earth oxide and silicate coating systems will be impacted in the presence of the CMAS at high temperatures and under simulated heat flux conditions. Advanced environmental barrier coating systems, including HfO2-Si with rare earth dopant based bond coat systems, will be discussed for the performance improvements to achieve better temperature capability and CMAS resistance for future engine operating conditions.

  10. Calcium and magnesium content of the uterine fluid and blood serum during the estrous cycle and pre-pubertal phase in water buffaloes.

    PubMed

    Alavi Shoushtari, Sayed Mortaza; Asri Rezaie, Siamak; Khaki, Amir; Belbasi, Abulfazle; Tahmasebian, Hamid

    2014-01-01

    To investigate uterine fluid and serum calcium (Ca) and Magnesium (Mg) variations during the estrus cycle in water buffaloes, 71 genital tracts and blood samples were collected from the abattoir in Urmia. The phase of the estrous cycle was determined by examining ovarian structures. 18 animals were pro-estrous, 15 estrous, 16 met-estrous and 22 diestrous. The uterine fluid was collected by gentle scraping of the uterine mucosa with a curette. Blood serum and uterine fluid samples of 71 pre-pubertal buffalo calves were also collected and treated in similar manners. The mean ± SEM total serum and uterine fluid Ca in cyclic buffaloes were 8.68 ± 0.28 mg dL(-1) and 8.10 ± 0.2 mg dL(-1) vs. 6.76 ± 0.65 mg dL(-1) and 7.90 ± 0.15 mg dL(-1) in pre-pubertal calves, respectively. Blood serum Mg was not different in cyclic and pre-pubertal animals but the uterine fluid Mg in cyclic cows was higher than those in pre-pubertal calves. Serum Ca in pro-estrus and estrus were higher than those in other stages and also higher than those in the uterine fluid. The lowest Mg content of serum was recorded in diestrus, while in the uterine fluid it was observed in estrus. In all stages of estrous cycle except for estrus the uterine fluid Mg content was significantly higher than those of the serum. These results suggested that during the estrous cycle in the buffalo cows, Ca was passively secreted in uterine lumen and mostly dependent on blood serum Ca concentrations but Mg was secreted independently. The values (except for serum total Mg) also increased after puberty.

  11. Evidence for cross-tolerance to nutrient deficiency in three disjunct populations of Arabidopsis lyrata ssp. lyrata in response to substrate calcium to magnesium ratio.

    PubMed

    Veatch-Blohm, Maren E; Roche, Bernadette M; Campbell, Maryjean

    2013-01-01

    Species with widespread distributions that grow in varied habitats may consist of ecotypes adapted to a particular habitat, or may exhibit cross-tolerance that enables them to exploit a variety of habitats. Populations of Arabidopsis lyrata ssp. lyrata (L.) O'Kane & Al-Shehbaz grow in a wide variety of edaphic settings including serpentine soil, limestone sand, and alluvial flood plains. While all three of these environments share some stressors, a crucial difference among these environments is soil calcium to magnesium ratio, which ranges from 25:1 in the limestone sand to 0.2:1 in serpentine soil. The three populations found on these substrates were subjected to three different Ca to Mg ratios under controlled environmental conditions during germination and rosette growth. Response to Ca to Mg ratio was evaluated through germination success and radicle growth rate, rosette growth rate, and the content of Ca and Mg in the rosette. All three populations were particularly efficient in fueling growth under nutrient deficiency, with the highest nutrient efficiency ratio for Ca under Ca deficiency and for Mg under Mg deficiency. Although the serpentine population had significantly higher leaf Ca to Mg ratio than the limestone or flood plain populations under all three Ca to Mg ratios, this increase did not result in any advantage in growth or appearance of the serpentine plants, during early life stages before the onset of flowering, even in the high Mg substrate. The three populations showed no population by substrate interaction for any of the parameters measured indicating that these populations may have cross-tolerance to substrate Ca to Mg ratio.

  12. The Association between the Risk of Premenstrual Syndrome and Vitamin D, Calcium, and Magnesium Status among University Students: A Case Control Study

    PubMed Central

    Saeedian Kia, Afsaneh; Amani, Reza; Cheraghian, Bahman

    2015-01-01

    Background: Premenstrual syndrome (PMS) is one of major health problems in childbearing age women. Herein, we compared the nutritional status of vitamin D, calcium (Ca) and magnesium (Mg) in young students affected by PMS with those of normal participants. Methods: This study was conducted on 62 students aged 20‒25 yr in the city of Abadan (31 PMS cases and 31 controls). All participants completed four or more criteria according to the Utah PMS Calendar 3. Age, height, body mass index (BMI), serum Ca, Mg and vitamin D levels and a 24-hour food recall questionnaire were recorded. Results: Vitamin D serum levels were lower than the normal range in the two groups. The odds ratios (CI 95%) of having PMS based on serum Ca and Mg concentrations were 0.81(0.67 – 0.89) and 0.86 (0.72 – 0.93), respectively. Based on serum levels, 855 of all participants showed vitamin D deficiency and more than one-third of the PMS cases were Mg deficient (P<0.05). In addition, there were signifi­cant differences in dietary intake of Ca and Mg, and potassium but not vitamin D in the two groups. Dietary intakes of Ca and Mg were quite below the recommendation in all participants. Conclusion: Vitamin D, Ca and Mg nutritional status are compromised in PMS subjects. Because PMS is a prevalent health problem among young women, it merits more attention regarding improvement of their health and nutritional status. PMID:26634201

  13. Concentration of Zinc, Copper, Iron, Calcium, and Magnesium in the Serum, Tissues, and Urine of Streptozotocin-Induced Mild Diabetic Rat Model.

    PubMed

    Gómez, Tahiry; Bequer, Leticia; Mollineda, Angel; Molina, José L; Álvarez, Alain; Lavastida, Mayrelis; Clapés, Sonia

    2017-03-03

    The present study aimed to investigate, in the streptozotocin-induced mild diabetic rat model, the zinc (Zn), copper (Cu), iron (Fe), calcium (Ca), and magnesium (Mg) concentration in serum, liver, and kidney tissues, and urine samples from adult Wistar rats treated neonatally with streptozotocin (STZ). Diabetes was induced by subcutaneous administration of streptozotocin (100 mg/Kg) in female Wistar rats of 2 days old (STZ, n = 10). Control group (CG, n = 10) received only sodium-citrate buffer. The mineral concentrations were measured by atomic absorption spectrophotometry. The validity and accuracy were checked by conventional methods. STZ neonatal injection successfully leaded to mild diabetes in the adult rats. Serum concentrations of Zn, Cu, Fe, Ca, and Mg showed no changes (p > 0.05) due to diabetes. The Zn, Fe, Ca, and Mg concentrations in liver and kidney tissues were not different (p > 0.05) between STZ and CG. The mean values of Cu were higher (p < 0.05) in liver and kidney samples from STZ as compared to CG. Urine minerals concentrations (Zn, Cu, Fe and Ca) in STZ-rats group were lower (p < 0.05) than CG. However, the content of all evaluated minerals in the excreted urine were higher (p < 0.01) in STZ-rats during a 24 h collection period. Urinary excretion of Zn, Cu, Fe, Ca, and Mg was strongly correlated with urinary volume during the 24 h period (r > 0.7; p < 0.001). Observed changes in mineral metabolism of STZ-induced mild diabetes model could be due to the endocrine imbalance associated with the diabetic condition.

  14. Role of magnesium and calcium in alcohol-induced hypertension and strokes as probed by in vivo television microscopy, digital image microscopy, optical spectroscopy, 31P-NMR, spectroscopy and a unique magnesium ion-selective electrode.

    PubMed

    Altura, B M; Altura, B T

    1994-10-01

    It is not known why alcohol ingestion poses a risk for development of hypertension, stroke and sudden death. Of all drugs, which result in body depletion of magnesium (Mg), alcohol is now known to be the most notorious cause of Mg-wasting. Recent data obtained through the use of biophysical (and noninvasive) technology suggest that alcohol may induce hypertension, stroke, and sudden death via its effects on intracellular free Mg2+ ([Mg2+]i), which in turn alter cellular and subcellular bioenergetics and promote calcium ion (Ca2+) overload. Evidence is reviewed that demonstrates that the dietary intake of Mg modulates the hypertensive actions of alcohol. Experiments with intact rats indicates that chronic ethanol ingestion results in both structural and hemodynamic alterations in the microcirculation, which, in themselves, could account for increased vascular resistance. Chronic ethanol increases the reactivity of intact microvessels to vasoconstrictors and results in decreased reactivity to vasodilators. Chronic ethanol ingestion clearly results in vascular smooth muscle cells that exhibit a progressive increase in exchangeable and cellular Ca2+ concomitant with a progressive reduction in Mg content. Use of 31P-NMR spectroscopy coupled with optical-backscatter reflectance spectroscopy revealed that acute ethanol administration to rats results in dose-dependent deficits in phosphocreatine (PCr), the [PCr]/[ATP] ratio, intracellular pH (pHi), oxyhemoglobin, and the mitochondrial level of oxidized cytochrome oxidase aa3 concomitant with a rise in brain-blood volume and inorganic phosphate. Temporal studies performed in vivo, on the intact brain, indicate that [Mg2+]i is depleted before any of the bioenergetic changes. Pretreatment of animals with Mg2+ prevents ethanol from inducing stroke and prevents all of the adverse bioenergetic changes from taking place. Use of quantitative digital imaging microscopy, and mag-fura-2, on single-cultured canine cerebral vascular

  15. Boron Induces Early Matrix Mineralization via Calcium Deposition and Elevation of Alkaline Phosphatase Activity in Differentiated Rat Bone Marrow Mesenchymal Stem Cells

    PubMed Central

    Movahedi Najafabadi, Bent-al-hoda; Abnosi, Mohammad Hussein

    2016-01-01

    Objective Boron (B) is essential for plant development and might be an essential micronutrient for animals and humans. This study was conducted to characterize the impact of boric acid (BA) on the cellular and molecular nature of differentiated rat bone marrow mesenchymal stem cells (BMSCs). Materials and Methods In this experimental study, BMSCs were extracted and expanded to the 3rdpassage, then cultured in Dulbecco’s Modified Eagle’s Medium (DMEM) complemented with osteogenic media as well as 6 ng/ml and 6 µg/ml of BA. After 5, 10, 15 and 21 days the viability and the level of mineralization was determined using MTT assay and alizarin red respectively. In addition, the morphology, nuclear diameter and cytoplasmic area of the cells were studied with the help of fluorescent dye. The concentration of calcium, activity of alanine transaminase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) as well as sodium and potassium levels were also evaluated using commercial kits and a flame photometer respectively. Results Although 6 µg/ml of BA was found to be toxic, a concentration of 6 ng/ml increased the osteogenic ability of the cell significantly throughout the treatment. In addition it was observed that B treatment caused the early induction of matrix mineralization compared to controls. Conclusion Although more investigation is required, we suggest the prescription of a very low concentration of B in the form of BA or foods containing BA, in groups at high risk of osteoporosis or in the case of bone fracture. PMID:27054120

  16. Deep formation waters of Western Europe, Russia and North America characterised by sodium, calcium, magnesium and chloride concentrations

    NASA Astrophysics Data System (ADS)

    Bozau, Elke; Hemme, Christina; Sattler, Carl-Diedrich; van Berk, Wolfgang

    2015-04-01

    Deep formation water can be classified according to depth, temperature, and salinity (e.g., Graf et al. 1966, Kharaka & Hanor 2007). Most of the deep formation waters contain dissolved solids in excess of sea water. The hydrogeochemical development of formation water has been discussed for a long time. It is widely accepted that deep aquifers are influenced by the meteoric cycle and geochemical processes within the crust (e.g., Hebig et al. 2012). Similar hydrogeochemical signatures are found in deep formation waters of all continents and can be explained by general geochemical processes within the deep reservoirs (e.g., Land 1995). Therefore, data of deep formation waters from Western Europe, Russia, and North America are collected and classified by the major water components. The data are used to identify important hydrogeochemical processes (e.g., halite dissolution and albitisation) leading to different compositions of formation water. Two significant water types are identified: Na-Cl water and Na-Ca-Cl water. Based on the collected hydrogeochemical data, development trends are stated for the formation waters, and albitisation is favoured as the main process for calcium enrichment. Furthermore, differences of formation water according to stratigraphical units are shown for deep reservoirs of the North German Basin and the North Sea. References: Graf, D.L., 1982. Chemical osmosis, reverse chemical osmosis, and the origin of subsurface brines. Geochimica Cosmochimica Acta 46, 1431-1448. Hebig, K.H., Ito, N., Scheytt, T., Marui, A., 2012. Review: Deep groundwater research with focus on Germany. Hydrogeology Journal 20, 227-243. Kharaka, Y.K., Hanor, J.S., 2007. Deep fluids in continents: I. Sedimentary Basins. Treatise on Geochemistry 5, 1-48. Land, L.S., 1995. The role of saline formation water in the crustal cycling. Aquatic Geochemistry 1, 137-145. Acknowledgements: The presented data are results of the collaborative research program "gebo" (Geothermal energy

  17. Alkaline flocculation of Phaeodactylum tricornutum induced by brucite and calcite

    SciTech Connect

    Vandamme, Dries; Pohl, Philip I.; Beuckels, Annelies; Foubert, Imogen; Brady, Patrick Vane; Muylaert, Koenraad; Hewson, John C.

    2015-08-20

    Alkaline flocculation holds great potential as a low-cost harvesting method for marine microalgae biomass production. Alkaline flocculation is induced by an increase in pH and is related to precipitation of calcium and magnesium salts. In this study, we used the diatom Phaeodactylum tricornutum as model organism to study alkaline flocculation of marine microalgae cultured in seawater medium. Flocculation started when pH was increased to 10 and flocculation efficiency reached 90% when pH was 10.5, which was consistent with precipitation modeling for brucite or Mg(OH)2. Compared to freshwater species, more magnesium is needed to achieve flocculation (>7.5 mM). Zeta potential measurements suggest that brucite precipitation caused flocculation by charge neutralization. When calcium concentration was 12.5 mM, flocculation was also observed at a pH of 10. Furthermore, zeta potential remained negative up to pH 11.5, suggesting that precipitated calcite caused flocculation by a sweeping coagulation mechanism.

  18. Effect of magnesium on the aluminothermic reduction rate of zinc oxide obtained from spent alkaline battery anodes for the preparation of Al-Zn-Mg alloys

    NASA Astrophysics Data System (ADS)

    Ochoa, Rocio; Flores, Alfredo; Torres, Jesus

    2016-04-01

    The aluminothermic reduction of zinc oxide (ZnO) from alkaline battery anodes using molten Al may be a good option for the elaboration of secondary 7000-series alloys. This process is affected by the initial content of Mg within molten Al, which decreases the surface tension of the molten metal and conversely increases the wettability of ZnO particles. The effect of initial Mg concentration on the aluminothermic reduction rate of ZnO was analyzed at the following values: 0.90wt%, 1.20wt%, 4.00t%, 4.25wt%, and 4.40wt%. The ZnO particles were incorporated by mechanical agitation using a graphite paddle inside a bath of molten Al maintained at a constant temperature of 1123 K and at a constant agitation speed of 250 r/min, the treatment time was 240 min and the ZnO particle size was 450-500 mesh. The results show an increase in Zn concentration in the prepared alloys up to 5.43wt% for the highest initial concentration of Mg. The reaction products obtained were characterized by scanning electron microscopy and X-ray diffraction, and the efficiency of the reaction was measured on the basis of the different concentrations of Mg studied.

  19. Ocean alkalinity and the Cretaceous/Tertiary boundary

    NASA Technical Reports Server (NTRS)

    Caldeira, K. G.; Rampino, Michael R.

    1988-01-01

    A biogeochemical cycle model resolving ocean carbon and alkalinity content is applied to the Maestrichtian and Danian. The model computes oceanic concentrations and distributions of Ca(2+), Mg(2+), and Sigma-CO2. From these values an atmospheric pCO2 value is calculated, which is used to estimate rates of terrestrial weathering of calcite, dolomite, and calcium and magnesium silicates. Metamorphism of carbonate rocks and the subsequent outgassing of CO2 to the atmosphere are parameterized in terms of carbonate rock reservoir sizes, total land area, and a measure of overall tectonic activity, the sea-floor generation rate. The ocean carbon reservoir computed by the model is used with Deep Sea Drilling Project (DSDP) C-13 data to estimate organic detrital fluxes under a variety of ocean mixing rate assumptions. Using Redfield ratios, the biogenic detrital flux estimate is used to partition the ocean carbon and alkalinity reservoirs between the mixed layer and deep ocean. The calcite flux estimate and carbonate ion concentrations are used to determine the rate of biologically mediated CaCO3 titration. Oceanic productivity was severely limited for approximately 500 kyr following the K/T boundary resulting in significant increases in total ocean alkalinity. As productivity returned to the ocean, excess carbon and alkalinity was removed from the ocean as CaCO3. Model runs indicate that this resulted in a transient imbalance in the other direction. Ocean chemistry returned to near-equilibrium by about 64 mybp.

  20. Calcium and bone disease

    PubMed Central

    Blair, Harry C.; Robinson, Lisa J.; Huang, Christopher L.-H.; Sun, Li; Friedman, Peter A.; Schlesinger, Paul H.; Zaidi, Mone

    2013-01-01

    Calcium transport and calcium signaling are of basic importance in bone cells. Bone is the major store of calcium and a key regulatory organ for calcium homeostasis. Bone, in major part, responds to calcium-dependent signals from the parathyroids and via vitamin D metabolites, although bone retains direct response to extracellular calcium if parathyroid regulation is lost. Improved understanding of calcium transporters and calcium-regulated cellular processes has resulted from analysis of genetic defects, including several defects with low or high bone mass. Osteoblasts deposit calcium by mechanisms including phosphate and calcium transport with alkalinization to absorb acid created by mineral deposition; cartilage calcium mineralization occurs by passive diffusion and phosphate production. Calcium mobilization by osteoclasts is mediated by acid secretion. Both bone forming and bone resorbing cells use calcium signals as regulators of differentiation and activity. This has been studied in more detail in osteoclasts, where both osteoclast differentiation and motility are regulated by calcium. PMID:21674636

  1. Magnesium and magnesium alloys

    SciTech Connect

    Avedesian, M.; Baker, H.

    1998-12-31

    This new handbook is the most comprehensive publication of engineering information on commercial magnesium alloys under one cover in the last sixty years. Prepared with the cooperation of the International Magnesium Association, it presents the industrial practices currently used throughout the world, as well as the properties of the products critical to their proper application. Contents include: general characteristics; physical metallurgy; melting, refining, alloying, recycling, and powder production; casting; heat treatment; forging, rolling, and extrusion; semisolid processing; forming; joining; cleaning and finishing; selection, application, and properties of grades and alloys; design considerations; mechanical behavior and wear resistance; fatigue and fracture-mechanics; high-temperature strength and creep; corrosion and stress-corrosion cracking; specification.

  2. Effect of dietary Garcinia cambogia extract on serum essential minerals (calcium, phosphorus, magnesium) and trace elements (iron, copper, zinc) in rats fed with high-lipid diet.

    PubMed

    Gürsel, Feraye Esen; Ateş, Atila; Bilal, Tanay; Altiner, Ayşen

    2012-09-01

    The aim of the study was to investigate the effect of Garcinia cambogia extract on serum calcium (Ca), phosphorus (P), magnesium (Mg), iron (Fe), zinc (Zn) and copper (Cu) concentrations in rats fed with the normal or the high-lipid and -cholesterol diet. Thirty 1-year-old female Sprague-Dawley rats (pathogen-free), weighing an average of 229 g, were randomly assigned to three experimental groups of ten animals each. Diets and tap water were given ad libitum for 75 days. Group 1 (control group) was fed with basal diet (2 % liquid vegetable oil, 0 % cholesterol), while the diets of groups 2 and 3 contained vegetable oil (2 % liquid vegetable oil and 5 % hydrogenated vegetable oil) and cholesterol (3 %) in high levels. 4,5 % G. cambogia extract containing 65 % HCA was added to the diet of group 3 as from day 45. Blood samples were withdrawn on days 0, 45 and 75. Serum mineral levels were analyzed using standard enzymatic colorimetric methods with a spectrophotometer. All significant differences were p<0.05. Serum Ca levels were not significantly different between all groups on days 45 and 75. Serum P level was significantly higher in the group fed with high-lipid diet and G. cambogia extract than in the control group on day 45. Serum Mg level was significantly higher in group 2 than in the control group on day 45. Serum Fe levels were significantly lower in the control group than in the other groups on days 45 and 75. Serum Zn level of the group fed with high-lipid diet and G. cambogia extract was significantly higher than in the control group on day 75. Serum Cu levels were significantly higher in group 2 than in the control group, and in group 3 than in group 2 on day 75. In conclusion, a diet containing the high fat amounts may lead to the increase in circular levels of some minerals due to the short-chain fatty acid production lowering the luminal pH which increases mineral solubility, or serving as a fuel for mucosal cells and stimulating cell proliferation in

  3. Non-free ionic transport of sodium, magnesium, and calcium in streams of two adjacent headwater catchments with different vegetation types in Japan

    NASA Astrophysics Data System (ADS)

    Terajima, Tomomi; Moriizumi, Mihoko; Nakamura, Tomohiro

    2017-01-01

    Sodium (Na), magnesium (Mg), calcium (Ca) are usually believed to occur mostly as free ions in the fresh water and consequently little is known about their chemical species. To understand the importance of non-free ionic fractions (NIF) of major metals in freshwater streams, Na, Mg, Ca, silicon (Si), and fulvic acid-like materials (FAM) were measured in streams of mountainous adjacent headwater catchments dominated by different vegetation types (planted evergreen coniferous forest and natural deciduous broadleaf forest). During both no rainfall periods and rainstorms, the proportion of NIF relative to total elements was lower in the coniferous catchment than in the deciduous catchment, although it sometimes accounted for half or more of the total concentrations of Na, Mg, and Ca in both catchments. The solubility of metal compounds was higher than the measured maximum concentrations of Na+, Mg2+, and Ca2+ to the extent that inorganic bonding was hardly possible. During no rainfall periods when FAM was slightly produced into the streams, the fluxes of NIF and Si were highly correlated (r > 0.92, p < 0.0001, n = 30) in both catchments. During a small rainstorm, the flux of NIF correlated weakly with that of Si but did not correlate with that of FAM in both catchments. In contrast, during a heavy rainstorm, the flux of NIF correlated strongly (r ⩾ 0.83, p < 0.0001, n = 26) with that of FAM in the deciduous catchment where relatively deep soil water compared to near-surface water was the predominant component of stream water. However, during the heavy rainstorm in the coniferous catchment, only the flux of NIF originated in the quick-flow component (i.e., surface or near-surface water) in stream water (ΔNIF) correlated strongly (r ⩾ 0.81, p < 0.0001, n = 22) with that of FAM. These findings imply that heavy rainstorms may enhance the bonding of the major metals with humic substances mainly in the deciduous catchment; and also exhibit that, in the headwater

  4. Extracellular magnesium regulates nuclear and perinuclear free ionized calcium in cerebral vascular smooth muscle cells: possible relation to alcohol and central nervous system injury.

    PubMed

    Altura, B M; Zhang, A; Cheng, T P; Altura, B T

    2001-02-01

    Quantitative digital imaging microscopy, confocal laser scanning microscopy (CLSM), and multiple molecular fluorescent probes were utilized to test the hypothesis that cerebral vascular muscle cell nuclear ([Ca(2+)](n)), perinuclear ([Ca(2+)](pn)), and cytoplasmic free calcium ([Ca(2+)](i)) levels are regulated by the concentration of extracellular free magnesium ions ([Mg(2+)](o)). Primary cultured canine cerebral vascular smooth muscle cells were loaded with either fura-2/AM, indo-1/AM, or fluo-3/AM, and the subcellular Ca(2+) responses to stepwise reduction in [Mg(2+)](o) (i.e., from 1.36 to 0.17 mM) were analyzed over time. With normal 1.36 mM [Mg(2+)](o)-containing incubation media, basal mean [Ca(2+)](i) was 89.6+/-15 nM. Lowering [Mg(2+)](o) to 1.07, 0.88, 0.48, and 0.17 mM resulted in rapid (<4 min) increments in [Ca(2+)](i) going to 213+/-43, 368+/-67, 471+/-77, and 642+/-98 nM, respectively; the longer the exposure time (up to 30 min) to lowered [Mg(2+)](o), the higher the [Ca(2+)](i). Restoration of [Mg(2+)](o) to normal caused decreases in [Ca(2+)](i) to 215.9+/-42.3 nM, but only complete removal of [Ca(2+)](o) returned [Ca(2+)](i) to basal levels. Results show that basal [Ca(2+)](pn) (282+/-92 nM) exceeds basal cytoplasmic Ca(2+) (61+/-27.8 nM) and [Ca(2+)](n) (20+/-7.6 nM). However, reduction of normal [Mg(2+)](o) to 0.48 mM resulted in dramatic, rapid rises in all subcellular compartments, where [Ca(2+)](pn) (1503+/-102 nM)>cytoplasmic Ca(2+) (688+/-49 nM) approximately equal to [Ca(2+)](n) (674+/-12 nM). Nuclear Ca(2+) rose dramatically (e.g., 35-40 times basal levels). Both verapamil (1 microM) and Ni(2+) (5 mM) prevented, completely, the rises in Ca(2+) in all compartments, suggesting that Mg(2+)-dependent Ca(2+) accumulation may be dependent on nuclear, endoplasmic reticulum-Golgi, and cytoplasmic L-type voltage membrane-regulated Ca(2+) channels. The normally low [Ca(2+)](n) suggests that Ca(2+) does not transport passively across the nuclear

  5. Photosynthetic and Growth Response of Sugar Maple (Acer saccharum Marsh.) Mature Trees and Seedlings to Calcium, Magnesium, and Nitrogen Additions in the Catskill Mountains, NY, USA

    PubMed Central

    Momen, Bahram; Behling, Shawna J.; Lawrence, Greg B.; Sullivan, Joseph H.

    2015-01-01

    Decline of sugar maple in North American forests has been attributed to changes in soil calcium (Ca) and nitrogen (N) by acidic precipitation. Although N is an essential and usually a limiting factor in forests, atmospheric N deposition may cause N-saturation leading to loss of soil Ca. Such changes can affect carbon gain and growth of sugar maple trees and seedlings. We applied a 22 factorial arrangement of N and dolomitic limestone containing Ca and Magnesium (Mg) to 12 forest plots in the Catskill Mountain region of NY, USA. To quantify the short-term effects, we measured photosynthetic-light responses of sugar maple mature trees and seedlings two or three times during two summers. We estimated maximum net photosynthesis (An-max) and its related light intensity (PAR at An-max), apparent quantum efficiency (Aqe), and light compensation point (LCP). To quantify the long-term effects, we measured basal area of living mature trees before and 4 and 8 years after treatment applications. Soil and foliar chemistry variables were also measured. Dolomitic limestone increased Ca, Mg, and pH in the soil Oe horizon. Mg was increased in the B horizon when comparing the plots receiving N with those receiving CaMg. In mature trees, foliar Ca and Mg concentrations were higher in the CaMg and N+CaMg plots than in the reference or N plots; foliar Ca concentration was higher in the N+CaMg plots compared with the CaMg plots, foliar Mg was higher in the CaMg plots than the N+CaMg plots; An-max was maximized due to N+CaMg treatment; Aqe decreased by N addition; and PAR at An-max increased by N or CaMg treatments alone, but the increase was maximized by their combination. No treatment effect was detected on basal areas of living mature trees four or eight years after treatment applications. In seedlings, An-max was increased by N+CaMg addition. The reference plots had an open herbaceous layer, but the plots receiving N had a dense monoculture of common woodfern in the forest floor

  6. Photosynthetic and growth response of sugar maple (Acer saccharum Marsh.) mature trees and seedlings to calcium, magnesium, and nitrogen additions in the Catskill Mountains, NY, USA

    USGS Publications Warehouse

    Momen, Bahram; Behling, Shawna J; Lawrence, Gregory B.; Sullivan, Joseph H

    2015-01-01

    Decline of sugar maple in North American forests has been attributed to changes in soil calcium (Ca) and nitrogen (N) by acidic precipitation. Although N is an essential and usually a limiting factor in forests, atmospheric N deposition may cause N-saturation leading to loss of soil Ca. Such changes can affect carbon gain and growth of sugar maple trees and seedlings. We applied a 22 factorial arrangement of N and dolomitic limestone containing Ca and Magnesium (Mg) to 12 forest plots in the Catskill Mountain region of NY, USA. To quantify the short-term effects, we measured photosynthetic-light responses of sugar maple mature trees and seedlings two or three times during two summers. We estimated maximum net photosynthesis (An-max) and its related light intensity (PAR at An-max), apparent quantum efficiency (Aqe), and light compensation point (LCP). To quantify the long-term effects, we measured basal area of living mature trees before and 4 and 8 years after treatment applications. Soil and foliar chemistry variables were also measured. Dolomitic limestone increased Ca, Mg, and pH in the soil Oe horizon. Mg was increased in the B horizon when comparing the plots receiving N with those receiving CaMg. In mature trees, foliar Ca and Mg concentrations were higher in the CaMg and N+CaMg plots than in the reference or N plots; foliar Ca concentration was higher in the N+CaMg plots compared with the CaMg plots, foliar Mg was higher in the CaMg plots than the N+CaMg plots; An-max was maximized due to N+CaMg treatment; Aqe decreased by N addition; and PAR at An-max increased by N or CaMg treatments alone, but the increase was maximized by their combination. No treatment effect was detected on basal areas of living mature trees four or eight years after treatment applications. In seedlings, An-max was increased by N+CaMg addition. The reference plots had an open herbaceous layer, but the plots receiving N had a dense monoculture of common woodfern in the

  7. Influence of the dosing frequency of parathyroid hormone-(1-38) on its anabolic effect in bone and on the balance of calcium, phosphorus and magnesium.

    PubMed

    Riond, J L; Goliat-von Fischer, I; Küffer, B; Toromanoff, A; Forrer, R

    1998-06-01

    The effect of the frequency of administration of synthetic human parathyroid hormone fragment 1-38 [hPTH-(1-38)] on bone formation and on the balance of calcium, phosphorus, and magnesium was investigated in 32 9-week-old female Sprague-Dawley rats, using a randomly complete block design. Rats received subcutaneously during 14 days either the vehicle solution once a day or 50 micrograms hPTH-(1-38)/kg BW once a day at 8:00 a.m., twice a day at 8:00 a.m. and 5:00 p.m. or three times a day at 8:00 a.m., 0:30 p.m., and 5:00 p.m. The balance study was performed during the last 48 h of the hPTH-(1-38) treatment schedule after which femora, tibiae, and lumbar vertebrae were removed for the determination of the dry weight, volume, and contents of Ca, P, Mg, hydroxyproline, and DNA. PTH treatment was associated with a significant increase of the apparent intestinal absorption of Ca, P, and Mg. Mean urinary Ca excretion augmented with the increase of the frequency of dosing. Urinary Ca excretion correlated negatively with the Ca apparent intestinal absorption and with the Ca content of the tibiae in the 2 groups with the highest frequency of dosing. The mean Ca, P, and Mg balances, the mean contents of bone Ca, P, and Mg and the mean bone dry weights were significantly increased with PTH treatment. In contrast to the mean volume of tibiae which was not affected by the PTH administration, the mean volume of the fifth lumbar vertebrae increased with the treatment. With the 2 times and 3 times daily treatments, mean hydroxyproline concentrations in the femora were significantly higher than the control values. An increase of the mean hydroxyproline content of the third lumbar vertebrae was evidenced with the 1 time and 2 times daily treatment, but the mean of the highest frequency of dosing was not different from that of the control group. The DNA content of femoral and of the fourth lumbar vertebrae significantly decreased with the frequency of dosing.

  8. Photosynthetic and Growth Response of Sugar Maple (Acer saccharum Marsh.) Mature Trees and Seedlings to Calcium, Magnesium, and Nitrogen Additions in the Catskill Mountains, NY, USA.

    PubMed

    Momen, Bahram; Behling, Shawna J; Lawrence, Greg B; Sullivan, Joseph H

    2015-01-01

    Decline of sugar maple in North American forests has been attributed to changes in soil calcium (Ca) and nitrogen (N) by acidic precipitation. Although N is an essential and usually a limiting factor in forests, atmospheric N deposition may cause N-saturation leading to loss of soil Ca. Such changes can affect carbon gain and growth of sugar maple trees and seedlings. We applied a 22 factorial arrangement of N and dolomitic limestone containing Ca and Magnesium (Mg) to 12 forest plots in the Catskill Mountain region of NY, USA. To quantify the short-term effects, we measured photosynthetic-light responses of sugar maple mature trees and seedlings two or three times during two summers. We estimated maximum net photosynthesis (An-max) and its related light intensity (PAR at An-max), apparent quantum efficiency (Aqe), and light compensation point (LCP). To quantify the long-term effects, we measured basal area of living mature trees before and 4 and 8 years after treatment applications. Soil and foliar chemistry variables were also measured. Dolomitic limestone increased Ca, Mg, and pH in the soil Oe horizon. Mg was increased in the B horizon when comparing the plots receiving N with those receiving CaMg. In mature trees, foliar Ca and Mg concentrations were higher in the CaMg and N+CaMg plots than in the reference or N plots; foliar Ca concentration was higher in the N+CaMg plots compared with the CaMg plots, foliar Mg was higher in the CaMg plots than the N+CaMg plots; An-max was maximized due to N+CaMg treatment; Aqe decreased by N addition; and PAR at An-max increased by N or CaMg treatments alone, but the increase was maximized by their combination. No treatment effect was detected on basal areas of living mature trees four or eight years after treatment applications. In seedlings, An-max was increased by N+CaMg addition. The reference plots had an open herbaceous layer, but the plots receiving N had a dense monoculture of common woodfern in the forest floor

  9. Calcium carbonate with magnesium overdose

    MedlinePlus

    ... K. General approach to the poisoned patient. In: Marx JA, Hockberger RS, Walls RM, eds. Rosen's Emergency ... 147. Pfennig CL, Slovis CM. Electrolyte disorders. In: Marx JA, Hockberger RS, Walls RM, eds. Rosen's Emergency ...

  10. The Role of Alkalinity Inputs in the Composition of Sediments in AN Acid Mine Drainage Remediated Stream: Hewett Fork, Ohio

    NASA Astrophysics Data System (ADS)

    Lopez, D. L.; Korenowsky, R. K.; Kruse, N.; Bowman, J.

    2012-12-01

    Hewett Fork, a tributary of Raccoon Creek in SE Ohio, is severely impacted by acid mine drainage. This stream is being actively treated using a calcium oxide doser. In this work, we report the results of our investigations into the chemical effect of remediation in the stream throughout an evaluation of the chemical composition of its sediments. Results show that the grain size of the sediments is finer in the areas where high alkalinity loads enter the stream, at the output from the doser and downstream of the confluence with alkaline tributaries. The composition of heavy metals (magnesium, aluminum, calcium, nickel, zinc, manganese, potassium, lead, chromium, copper, cobalt and arsenic) is higher in concentration in the fine-grained sediments where alkalinity enters the stream, forming two peaks of high sediment concentration along the stream, one at the doser and the second after the confluence with alkaline tributaries. Iron has a different behavior with a higher sediment concentration downstream from the doser at the areas where the grain size is larger, due to the kinetics of the oxidation process for the formation of iron (III) minerals. These results suggest that in remediation of acid-mine-drainage impacted streams, alkalinity inputs along and oxidation processes are important for the storage of heavy metals in the sediments.

  11. Structural diversity of alkaline-earth 2,5-thiophenedicarboxylates

    NASA Astrophysics Data System (ADS)

    Balendra; Ramanan, Arunachalam

    2017-03-01

    Exploration of the structural landscape of the system containing divalent alkaline-earth metal ion (Mg, Ca and Sr) with the rigid 2,5-thiophenedicarboxylic acid (TDC) under varying solvothermal condition (DMF, DMA and DEF) yielded five new crystals: [Mg(TDC) (DEF)2(H2O)1/2] (1), [Ca(TDC) (DMA)] (2), [Ca(TDC) (DMA) (H2O)] (3), [Sr(TDC) (DMA)] (4) and [Sr(TDC) (DMA) (H2O)] (5) and two known solids. Single crystal structures of all the solids are characteristic of extended coordination interaction between metal and carboxylate ions. While the smaller magnesium ion crystallized into a 2D coordination polymer, the larger calcium and strontium compounds resulted into the growth of 3D metal organic frameworks. All the solids show blue emission arising from intra ligand charge transfer.

  12. Effect of magnesium/calcium ratios in solutions treated by electrodialysis: morphological characterization and identification of anion-exchange membrane fouling.

    PubMed

    Casademont, Christophe; Pourcelly, Gérald; Bazinet, Laurent

    2008-06-01

    The present study aimed the characterization of the fouling formed on anion-exchange membrane during electrodialysis treatment of model salt solutions at different Mg/Ca ratio (0, 1/20, 1/10, 1/5 and 2/5). The membrane fouling was characterized by membrane parameters (membrane thickness and electrical conductivity) and identified by membrane surface analysis (elemental analysis and X-ray diffraction). The mineral deposit was identified as Ca(OH)2 when no magnesium was present in the model salt. As soon as magnesium was present in the model salt solution for neutral pH((concentrate)) conditions a mix between CaCO3 and Ca(OH)2 was formed. This study is the first one to report the influence of magnesium in solution on the formation of CaCO3 fouling at the interface of anion-exchange membrane during electrodialysis.

  13. Effects of calcium magnesium carbonate and roughage level on feedlot performance, ruminal metabolism, and site and extent of digestion in steers fed high-grain diets.

    PubMed

    Crawford, G I; Keeler, C D; Wagner, J J; Krehbiel, C R; Erickson, G E; Crombie, M B; Nunnery, G A

    2008-11-01

    A feedlot growth performance experiment and 2 metabolism experiments were conducted to evaluate dietary roughage concentration and calcium magnesium carbonate in steers fed a high-grain diet. In Exp. 1, one hundred ninety-two crossbred yearling steers (320 +/- 10 kg of initial BW) were fed diets based on steam-flaked corn with 0, 0.75, or 1.5% CaMg(CO(3))(2). There were no effects (P > or = 0.13) on ADG, DMI, G:F, or total water intake due to CaMg(CO(3))(2). In Exp. 2, five ruminally and duodenally fistulated steers (263 +/- 9 kg of initial BW) were used in a 5 x 5 Latin square design, with 5 dietary treatments arranged in a 2 x 2 + 1 factorial: 1) 3.8% dietary roughage and no CaMg(CO(3))(2); 2) 7.6% dietary roughage and no CaMg(CO(3))(2); 3) 11.4% dietary roughage and no CaMg(CO(3))(2); 4) 3.8% dietary roughage and 1.5% CaMg(CO(3))(2); and 5) 7.6% dietary roughage and 1.5% CaMg(CO(3))(2). Water consumption was less (quadratic, P = 0.003) when 7.6% dietary roughage was fed compared with 3.8 or 11.4% dietary roughage. Intake of DM was not affected (P > or = 0.16) by dietary roughage or by CaMg(CO(3))(2). Poststomach and total tract starch digestion decreased (linear, P < 0.01) as dietary roughage increased. Ruminal pH tended (P = 0.08) to increase as dietary roughage increased but was not affected (P = 0.60) by CaMg(CO(3))(2). In Exp. 3, DMI and ruminal pH were continuously monitored in a 6 x 6 Latin square design using 6 ruminally and duodenally fistulated Holstein steers (229 +/- 10 kg of initial BW). A 3 x 2 factorial treatment structure was utilized, with factors consisting of dietary roughage concentration (4.5, 9.0, or 13.5%) and CaMg(CO(3))(2) inclusion (0 or 1.0%) to replace MgO and partially replace lime-stone. A dietary roughage x CaMg(CO(3))(2) interaction (P = 0.01) occurred as steers consuming 13.5% roughage, 1.0% CaMg(CO(3))(2) had greater DMI per meal than those consuming 4.5% dietary roughage, no CaMg(CO(3))(2) and 9.0% dietary roughage, 1.0% Ca

  14. IUPAC-NIST Solubility Data Series. 95. Alkaline Earth Carbonates in Aqueous Systems. Part 2. Ca

    SciTech Connect

    De Visscher, Alex; Vanderdeelen, Jan

    2012-06-15

    The alkaline earth carbonates are an important class of minerals. This article is part of a volume in the IUPAC-NIST Solubility Data Series that compiles and critically evaluates solubility data of the alkaline earth carbonates in water and in simple aqueous electrolyte solutions. Part 1 outlined the procedure adopted in this volume, and presented the beryllium and magnesium carbonates. Part 2, the current paper, compiles and critically evaluates the solubility data of calcium carbonate. The chemical forms included are the anhydrous CaCO{sub 3} types calcite, aragonite, and vaterite, the monohydrate monohydrocalcite (CaCO{sub 3}{center_dot} H{sub 2}O), the hexahydrate ikaite (CaCO{sub 3}{center_dot}6H{sub 2}O), and an amorphous form. The data were analyzed with two model variants, and thermodynamic data of each form consistent with each of the models and with the CODATA key values for thermodynamics are presented.

  15. [Changes of serum alkaline phosphatase and electrolytes during 21 d head down bed-rest].

    PubMed

    Yao, Yong-jie; Sun, Xi-qing; Wang, Zhong-bo; Zhao, Shuang-bao; Yang, Chang-bin; Wu, Xing-yu

    2002-06-01

    Objective. To investigate the effect of simulated weightlessness on serum alkaline phosphatase (ALP), calcium, magnesium, chlorine and phosphorus. Method. 6 healthy males, aged 24.8 +/- 6.1, were exposed to -6 degrees HDT bed rest for 21 d. Activity of serum alkaline phosphatase, serum contents of calcium (Ca), magnesium (Mg), chlorine (Cl) and phosphorus (P) ions were assayed before HDT (d-3), on the 3rd, 10th and 21st day during HDT and after HDT (d+2). Ca was measured by methyl thymol blue method, P was determined with ultraviolet spectrophotography, determination of Mg and Cl were made with enzyme method, ALP was examined with 4-nitrobenzene phosphate method. Result. Serum Ca2+ levels were significantly higher at d10, d2l and d+2 than the value of d-3 (P<0.01). P3+ levels declined significantly on d2l as compared with d-3 (P<0.01). During the HDT and after HDT, Mg2+ declined to a level below that before HDT (P<0.05 or P<0.01). Cl- were significantly higher at d2l and d+2 than the value of d-3 (P<0.01). ALP level was higher on d2l than on d-3 (P<0.01). Conclusion. 21 d HDT induced increase of Ca, Cl, ALP, and decline of Mg and P. The changes may reflect the imbalance of metabolism.

  16. Osseous plate alkaline phosphatase is anchored by GPI.

    PubMed

    Pizauro, J M; Ciancaglini, P; Leone, F A

    1994-02-01

    Alkaline phosphatase activity was released up to 100% from the membrane by using 0.1 U of phosphatidylinositol-specific phospholipase C from B. thuringiensis. The M(r) of solubilized enzyme was 145,000 by Sephacryl S-300 gel filtration and 66,000 by SDS-PAGE, suggesting a dimeric structure. Solubilization of the membrane-bound enzyme with phospholipase C did not destroy its ability to hydrolyze p-nitrophenyl phosphate (PNPP) (264.3 mumol min-1 mg-1),ATP (42.0 mumol min-1 mg-1) and pyrophosphate (28.4 mumol min-1 mg-1). The hydrolysis of ATP and PNPP by solubilized enzyme exhibited "Michaelian" kinetics with K0.5 = 70 and 979 microM, respectively. For pyrophosphate, K0.5 was 128 microM and site-site interactions were observed (n = 1.4). Magnesium ions were stimulatory (Kd = 1.5 mM) but zinc ions were powerful non-competitive inhibitors (Kd = 6.2 microM) of solubilized enzyme. Treatment of solubilized alkaline phosphatase with Chellex 100 reduced the original PNPPase activity to 5%. Cobalt (K0.5 = 10.1 microM), magnesium (K0.5 = 29.5 microM) and manganese ions (K0.5 = 5 microM) restored the activity of the apoenzyme with positive cooperativity, suggesting that phosphatidylinositol-specific phospholipase C-solubilized alkaline phosphatase is a metalloenzyme. The stimulation of the apoenzyme by calcium ions (K0.5 = 653 microM) was lower than that observed for the other ions (26%) and exhibited site-site interactions (n = 0.7). Zinc ions had no effect on the apoenzyme of the solubilized enzyme.

  17. Final amended report on the safety assessment of Ammonium Thioglycolate, Butyl Thioglycolate, Calcium Thioglycolate, Ethanolamine Thioglycolate, Ethyl Thioglycolate, Glyceryl Thioglycolate, Isooctyl Thioglycolate, Isopropyl Thioglycolate, Magnesium Thioglycolate, Methyl Thioglycolate, Potassium Thioglycolate, Sodium Thioglycolate, and Thioglycolic Acid.

    PubMed

    Burnett, Christina L; Bergfeld, Wilma F; Belsito, Donald V; Klaassen, Curtis D; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

    2009-01-01

    This safety assessment includes Ammonium and Glyceryl Thioglycolate and Thioglycolic Acid Butyl, Calcium, Ethanolamine, Ethyl, Isooctyl, Isopropyl, Magnesium, Methyl, Potassium, and Sodium Thioglycolate, as used in cosmetics. Thioglycolates penetrate skin and distribute to the kidneys, lungs, small intestine, and spleen; excretion is primarily in urine. Thioglycolates were slightly toxic in rat acute oral toxicity studies. Thioglycolates are minimal to severe ocular irritants. Thioglycolates can be skin irritants in animal and in vitro tests, and can be sensitizers. A no-observable-adverse-effect level for reproductive and developmental toxicity of 100 mg/kg per day was determined using rats. Thioglycolates were not mutagenic, and there was no evidence of carcinogenicity. Thioglycolates were skin irritants in some clinical tests. Clinically significant adverse reactions to these ingredients used in depilatories are not commonly seen, suggesting current products are formulated to be practically nonirritating under conditions of recommended use. Formulators should take steps necessary to assure that current practices are followed.

  18. Isotopically pure magnesium isotope-24 is prepared from magnesium-24 oxide

    NASA Technical Reports Server (NTRS)

    Chellew, N. R.; Schilb, J. D.; Steunenberg, R. K.

    1968-01-01

    Apparatus is used to prepare isotopically pure magnesium isotope-24, suitable for use in neutron scattering and polarization experiments. The apparatus permits thermal reduction of magnesium-24 oxide with aluminum and calcium oxide, and subsequent vaporization of the product metal in vacuum. It uses a resistance-heated furnace tube and cap assembly.

  19. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2011-01-01

    Seawater and natural brines accounted for about 54 percent of U.S. magnesium compounds production in 2010. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash-Wendover and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its operation mentioned above.

  20. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2010-01-01

    Seawater and natural brines accounted for about 40 percent of U.S. magnesium compounds production in 2009. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Chemicals in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover, and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta from its operation mentioned above.

  1. Alkalization is responsible for antibacterial effects of corroding magnesium.

    PubMed

    Rahim, Muhammad Imran; Eifler, Rainer; Rais, Bushra; Mueller, Peter P

    2015-11-01

    Magnesium alloys are presently investigated as potential medical implant materials for temporary applications. Magnesium has been reported to have antibacterial activities and could therefore be used to prevent antibiotic treatment-resistant bacterial implant infections. For characterizing the effects of magnesium on infectious bacteria, bioluminescent S. aureus or P. aeruginosa were employed. The proliferation of both types of bacteria was suppressed in the presence of metallic magnesium and also in aqueous magnesium corrosion extracts. Of the two soluble corrosion products, magnesium ions were well tolerated while antibacterial activities correlated with increased pH levels of the supernatants. The alkaline pH alone was sufficient for the antibacterial effects which were completely abolished when the pH of the corrosion supernatants was neutralized. These results demonstrate that pH increases are necessary and sufficient for the antibacterial activity of metallic magnesium. In an animal model magnesium implants showed an enhanced but variable resistance to bacterial colonization.

  2. Production of magnesium metal

    DOEpatents

    Blencoe, James G [Harriman, TN; Anovitz, Lawrence M [Knoxville, TN; Palmer, Donald A [Oliver Springs, TN; Beard, James S [Martinsville, VA

    2010-02-23

    A process of producing magnesium metal includes providing magnesium carbonate, and reacting the magnesium carbonate to produce a magnesium-containing compound and carbon dioxide. The magnesium-containing compound is reacted to produce magnesium metal. The carbon dioxide is used as a reactant in a second process. In another embodiment of the process, a magnesium silicate is reacted with a caustic material to produce magnesium hydroxide. The magnesium hydroxide is reacted with a source of carbon dioxide to produce magnesium carbonate. The magnesium carbonate is reacted to produce a magnesium-containing compound and carbon dioxide. The magnesium-containing compound is reacted to produce magnesium metal. The invention further relates to a process for production of magnesium metal or a magnesium compound where an external source of carbon dioxide is not used in any of the reactions of the process. The invention also relates to the magnesium metal produced by the processes described herein.

  3. Zinc electrode in alkaline electrolyte

    SciTech Connect

    McBreen, J.

    1995-12-31

    The zinc electrode in alkaline electrolyte is unusual in that supersaturated zincate solutions can form during discharge and spongy or mossy zinc deposits can form on charge at low overvoltages. The effect of additives on regular pasted ZnO electrodes and calcium zincate electrodes is discussed. The paper also reports on in situ x-ray absorption (XAS) results on mossy zinc deposits.

  4. Alkaline phytase from lily pollen: Investigation of biochemical properties.

    PubMed

    Jog, Sonali P; Garchow, Barry G; Mehta, Bakul Dhagat; Murthy, Pushpalatha P N

    2005-08-15

    Phytases catalyze the hydrolysis of phytic acid (InsP6, myo-inositol hexakisphosphate), the most abundant inositol phosphate in cells. In cereal grains and legumes, it constitutes 3-5% of the dry weight of seeds. The inability of humans and monogastric animals such as swine and poultry to absorb complexed InsP6 has led to nutritional and environmental problems. The efficacy of supplemental phytases to address these issues is well established; thus, there is a need for phytases with a range of biochemical and biophysical properties for numerous applications. An alkaline phytase that shows unique catalytic properties was isolated from plant tissues. In this paper, we report on the biochemical properties of an alkaline phytase from pollen grains of Lilium longiflorum. The enzyme exhibits narrow substrate specificity, it hydrolyzed InsP6 and para-nitrophenyl phosphate (pNPP). Alkaline phytase followed Michaelis-Menten kinetics with a K(m) of 81 microM and V(max) of 217 nmol Pi/min/mg with InsP6 and a K(m) of 372 microM and V(max) of 1272 nmol Pi/min/mg with pNPP. The pH optimum was 8.0 with InsP6 as the substrate and 7.0 with pNPP. Alkaline phytase was activated by calcium and inactivated by ethylenediaminetetraacetic acid; however, the enzyme retained a low level of activity even in Ca2+-free medium. Fluoride as well as myo-inositol hexasulfate did not have any inhibitory affect, whereas vanadate inhibited the enzyme. The enzyme was activated by sodium chloride and potassium chloride and inactivated by magnesium chloride; the activation by salts followed the Hofmeister series. The temperature optimum for hydrolysis is 55 degrees C; the enzyme was stable at 55 degrees C for about 30 min. The enzyme has unique properties that suggest the potential to be useful as a feed supplement.

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

    PubMed

    Mohamed, N E

    2016-03-01

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

  6. Magnesium: its role in nutrition and carcinogenesis.

    PubMed

    Blaszczyk, Urszula; Duda-Chodak, Aleksandra

    2013-01-01

    Magnesium (Mg2+) plays a key role in many essential cellular processes such as intermediary metabolism, DNA replication and repair, transporting potassium and calcium ions, cell proliferation together with signalling transduction. Dietary sources rich in magnesium are whole and unrefined grains, seeds, cocoa, nuts, almonds and green leafy vegetables. Hard water is also considered to be an important source of magnesium beneficial to human health. The daily dietary intake of magnesium is however frequently found to be below that recommended in Western countries. Indeed, it is recognised that magnesium deficiency may lead to many disorders of the human body, where for instance magnesium depletion is believed to play an important role in the aetiology of the following; cardiovascular disease (including thrombosis, atherosclerosis, ishaemic heart disease, myocardial infarction, hypertension, arrhythmias and congestive heart failure in human), as well as diabetes mellitus, gastrointestinal (GI) tract disease, liver cirrhosis and diseases of the thyroid and parathyroid glands. Insufficient dietary intake of magnesium may also significantly affect the development and exacerbation ofADHD (Attention Deficit- Hyperactivity Disorder) symptoms in children. The known links between magnesium and carcinogenesis still remain unclear and complex, with conflicting results being reported from many experimental, epidemiological and clinical studies; further knowledge is thus required. Mg2+ ions are enzyme cofactors involved in DNA repair mechanisms that maintain genomic stability and fidelity. Any magnesium deficiencies could thereby cause a dysfunction of these systems to occur leading to DNA mutations. Magnesium deficiency may also be associated with inflammation and increased levels of free radicals where both inflammatory mediators and free radicals so arising could cause oxidative DNA damage and therefore tumour formation. The presented review article now provides a summary

  7. Preparation and characterization of a degradable magnesium phosphate bone cement.

    PubMed

    Yu, Ying; Xu, Chao; Dai, Honglian

    2016-12-01

    A kind of degradable magnesium phosphate bone cement (MPBC) was fabricated by using the mixed powders of magnesium oxide (MgO), potassium dihydrogen phosphate (KH2PO4) and calcium dihydrogen phosphate (Ca(H2PO4)2.H2O). As MgKPO4, the main product of MgO and KH2PO4 was alkaline, the Ca(H2PO4)2.H2O was added to neutralize the alkali of the system. And the effects of Ca(H2PO4)2.H2O on the performance of MPBC were discussed. The results showed that the adding of Ca(H2PO4)2.H2O extended the setting time, which was about 6 min to 18 min. The compressive strength increased first and then decreased, and maximum value reached 31.2 MPa after setting for 24 h without any additional pressure. The MPBC was degradable in Tris-HCl solution, and the extracts of the cytotoxicity assay showed that the MPBC had good biocompatibility, indicating that the MPBC had good biodegradable and biocompatible properties.

  8. Preparation and characterization of a degradable magnesium phosphate bone cement

    PubMed Central

    Yu, Ying; Xu, Chao; Dai, Honglian

    2016-01-01

    A kind of degradable magnesium phosphate bone cement (MPBC) was fabricated by using the mixed powders of magnesium oxide (MgO), potassium dihydrogen phosphate (KH2PO4) and calcium dihydrogen phosphate (Ca(H2PO4)2.H2O). As MgKPO4, the main product of MgO and KH2PO4 was alkaline, the Ca(H2PO4)2.H2O was added to neutralize the alkali of the system. And the effects of Ca(H2PO4)2.H2O on the performance of MPBC were discussed. The results showed that the adding of Ca(H2PO4)2.H2O extended the setting time, which was about 6 min to 18 min. The compressive strength increased first and then decreased, and maximum value reached 31.2 MPa after setting for 24 h without any additional pressure. The MPBC was degradable in Tris–HCl solution, and the extracts of the cytotoxicity assay showed that the MPBC had good biocompatibility, indicating that the MPBC had good biodegradable and biocompatible properties. PMID:27482465

  9. Production of magnesium metal

    DOEpatents

    Blencoe, James G [Harriman, TN; Anovitz, Lawrence M [Knoxville, TN; Palmer, Donald A [Oliver Springs, TN; Beard, James S [Martinsville, VA

    2012-04-10

    A process of producing magnesium metal includes providing magnesium carbonate, and reacting the magnesium carbonate to produce a magnesium-containing compound and carbon dioxide. The magnesium-containing compound is reacted to produce magnesium metal. The carbon dioxide is used as a reactant in a second process. In another embodiment of the process, a magnesium silicate is reacted with a caustic material to produce magnesium hydroxide. The magnesium hydroxide is reacted with a source of carbon dioxide to produce magnesium carbonate. The magnesium carbonate is reacted to produce a magnesium-containing compound and carbon dioxide. The magnesium-containing compound is reacted to produce magnesium metal. The invention also relates to the magnesium metal produced by the processes described herein.

  10. [Bone disease in patients undergoing chronic hemodialysis treatment and the role in its development of magnesium in drinking water used in the preparation of dialysis solution].

    PubMed

    Ionova, D; Monov, A; Baldzhiĭski, A

    1985-01-01

    Studying the role of magnesium on uremic osseous disease in patients on chroniohemodialysis we examined 50 patients with chrovic renal diseases, chronic renal insufficiency (CRI) and chroniodialysis treatment (CDT) with duration of the dialysis treatment from I to 10 years, 3 years on the average, and compared it with control groups of 20 patients with chronic renal diseases without CRI, with duration of the diseases from 3 to 22 years, 9 years on the average and 20 patients with chronic renal diseases and CRI (stage I--III) on conservative treatment, with a duration of the CRI from 0.5 to 6 years, 2 years on the average. The following indices were studied in all patients: serum levels of calcium, phosphorus, magnesium and alkaline phosphatase--montry, to the dialysis patients the samples were taken at the beginning of dialysis séance, and calcium and magnesium content in drinking water used for the preparation of dialysis solution, was twice yearly investigated. In accordance with the bibliographic check up, the bones of all patients adequate for study were photographed with "soft" (mu)-roentgen rays, three times for the observation period, but severe bone changes (osteonecrosis and fractures)--were not established. The level of magnesium in serum of the patients by the end of dialysis séances in the significant group of them was impressive (p less than 0,001).(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2012-01-01

    Seawater and natural brines accounted for about 57 percent of magnesium compounds produced in the United States in 2011. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties LLC from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia LLC in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash Wendover LLC and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma Inc. in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its brine operation in Michigan.

  12. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2002-01-01

    Seawater and natural brines accounted for about 60% of US magnesium compounds production in 2001. Dead-burned and caustic-calcined magnesias were recovered from seawater in Florida by Premier Chemicals. They were also recovered from Michigan well brines by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And Premier Chemicals recovered dead-burned and caustic-calcined magnesias from magnesite in Nevada. Reilly Industries and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah.

  13. Magnesium Test

    MedlinePlus

    ... too much. Deficiencies are typically seen with: Low dietary intake (seen in the elderly, malnourished , and with alcoholism ) Gastrointestinal disorders (such as Crohn's disease) Uncontrolled ... blood levels of magnesium are rarely due to dietary sources but are usually the result of an ...

  14. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2004-01-01

    Dead-burned and caustic-calcined magnesias were recovered from seawater by Premier Chemicals in Florida; from well brines in Michigan by Dow Chemical, Martin Marietta Magnesia Specialties, and Rohm & Haas; and from magnesite in Nevada by Premier Chemicals. Reilly Industries and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah.

  15. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2007-01-01

    Seawater and natural brines accounted for about 52 percent of U.S. magnesium compounds production in 2006. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from sea-water by Premier Chemicals in Florida; from well brines in Michigan by Martin Marietta and Rohm and Haas; and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from brucite by Applied Chemical Magnesias in Texas, from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta and Rohm and Haas from their operations mentioned above. About 59 percent of the magnesium compounds consumed in the United States was used for refractories that are used mainly to line steelmaking furnaces. The remaining 41 percent was consumed in agricultural, chemical, construction, environmental and industrial applications.

  16. Serum ionized magnesium in post-traumatic headaches.

    PubMed

    Marcus, J C; Altura, B T; Altura, B M

    2001-09-01

    The objective of this study was to determine the values of serum ionized magnesium, total magnesium, and ionized calcium/ionized magnesium ratios in children with headaches. One hundred thirty-five children with primary complaints of headaches were classified according to the criteria of the International Headache Society. Blood samples were obtained and tested for ionized magnesium (IMg(2+)), total magnesium, ionized calcium (ICa(2+)), and pH. The ICa(2+)/IMg(2+) ratio was calculated. Nine children were given a diagnosis of post-traumatic headache. Six of them had statistically significant (P <.05) lowered IMg(2+) levels and high ICa(2+)/IMg(2+) ratios. Abnormalities in serum IMg(2+) concentrations and ICa(2+)/IMg(2+) ratios were found in children with post-traumatic headaches, but total magnesium levels were normal.

  17. Microbial Community Evolution Is Significantly Impacted by the Use of Calcium Isosaccharinic Acid as an Analogue for the Products of Alkaline Cellulose Degradation

    PubMed Central

    Kyeremeh, Isaac A.; Charles, Christopher J.; Rout, Simon P.; Laws, Andrew P.

    2016-01-01

    Diasteriomeric isosaccharinic acid (ISA) is an important consideration within safety assessments for the disposal of the United Kingdoms’ nuclear waste legacy, where it may potentially influence radionuclide migration. Since the intrusion of micro-organisms may occur within a disposal concept, the impact of ISA may be impacted by microbial metabolism. Within the present study we have established two polymicrobial consortia derived from a hyperalkaline soil. Here, α-ISA and a diatereomeric mix of ISAs’ were used as a sole carbon source, reflecting two common substrates appearing within the literature. The metabolism of ISA within these two consortia was similar, where ISA degradation resulted in the acetogenesis and hydrogenotrophic methanogenesis. The chemical data obtained confirm that the diastereomeric nature of ISA is likely to have no impact on its metabolism within alkaline environments. High throughput sequencing of the original soil showed a diverse community which, in the presence of ISA allowed for the dominance the Clostridiales associated taxa with Clostridium clariflavum prevalent. Further taxonomic investigation at the genus level showed that there was in fact a significant difference (p = 0.004) between the two community profiles. Our study demonstrates that the selection of carbon substrate is likely to have a significant impact on microbial community composition estimations, which may have implications with respect to a safety assessment of an ILW-GDF. PMID:27806095

  18. Microbial Community Evolution Is Significantly Impacted by the Use of Calcium Isosaccharinic Acid as an Analogue for the Products of Alkaline Cellulose Degradation.

    PubMed

    Kyeremeh, Isaac A; Charles, Christopher J; Rout, Simon P; Laws, Andrew P; Humphreys, Paul N

    2016-01-01

    Diasteriomeric isosaccharinic acid (ISA) is an important consideration within safety assessments for the disposal of the United Kingdoms' nuclear waste legacy, where it may potentially influence radionuclide migration. Since the intrusion of micro-organisms may occur within a disposal concept, the impact of ISA may be impacted by microbial metabolism. Within the present study we have established two polymicrobial consortia derived from a hyperalkaline soil. Here, α-ISA and a diatereomeric mix of ISAs' were used as a sole carbon source, reflecting two common substrates appearing within the literature. The metabolism of ISA within these two consortia was similar, where ISA degradation resulted in the acetogenesis and hydrogenotrophic methanogenesis. The chemical data obtained confirm that the diastereomeric nature of ISA is likely to have no impact on its metabolism within alkaline environments. High throughput sequencing of the original soil showed a diverse community which, in the presence of ISA allowed for the dominance the Clostridiales associated taxa with Clostridium clariflavum prevalent. Further taxonomic investigation at the genus level showed that there was in fact a significant difference (p = 0.004) between the two community profiles. Our study demonstrates that the selection of carbon substrate is likely to have a significant impact on microbial community composition estimations, which may have implications with respect to a safety assessment of an ILW-GDF.

  19. Determination of calcium, copper, iron, magnesium, manganese, potassium, phosphorus, sodium, and zinc in fortified food products by microwave digestion and inductively coupled plasma-optical emission spectrometry: single-laboratory validation and ring trial.

    PubMed

    Poitevin, Eric

    2012-01-01

    A single-laboratory validation (SLV) and a ring trial (RT) were undertaken to determine nine nutritional elements in food products by inductively coupled plasma-optical emission spectrometry in order to modernize AOAC Official Method 984.27. The improvements involved extension of the scope to all food matrixes (including infant formula), optimized microwave digestion, selected analytical lines, internal standardization, and ion buffering. Simultaneous determination of nine elements (calcium, copper, iron, potassium, magnesium, manganese, sodium, phosphorus, and zinc) was made in food products. Sample digestion was performed through wet digestion of food samples by microwave technology with either closed- or open-vessel systems. Validation was performed to characterize the method for selectivity, sensitivity, linearity, accuracy, precision, recovery, ruggedness, and uncertainty. The robustness and efficiency of this method was proven through a successful RT using experienced independent food industry laboratories. Performance characteristics are reported for 13 certified and in-house reference materials, populating the AOAC triangle food sectors, which fulfilled AOAC criteria and recommendations for accuracy (trueness, recovery, and z-scores) and precision (repeatability and reproducibility RSD, and HorRat values) regarding SLVs and RTs. This multielemental method is cost-efficient, time-saving, accurate, and fit-for-purpose according to ISO 17025 Norm and AOAC acceptability criteria, and is proposed as an extended updated version of AOAC Official Method 984.27 for fortified food products, including infant formula.

  20. Insight into the local environment of magnesium and calcium in low-coordination-number organo-complexes using (25)Mg and (43)Ca solid-state NMR: a DFT study.

    PubMed

    Gervais, Christel; Jones, Cameron; Bonhomme, Christian; Laurencin, Danielle

    2017-03-01

    With the increasing number of organocalcium and organomagnesium complexes under development, there is a real need to be able to characterize in detail their local environment in order to fully rationalize their reactivity. For crystalline structures, in cases when diffraction techniques are insufficient, additional local spectroscopies like (25)Mg and (43)Ca solid-state NMR may provide valuable information to help fully establish the local environment of the metal ions. In this current work, a prospective DFT investigation on crystalline magnesium and calcium complexes involving low-coordination numbers and N-bearing organic ligands was carried out, in which the (25)Mg and (43)Ca NMR parameters [isotropic chemical shift, chemical shift anisotropy (CSA) and quadrupolar parameters] were calculated for each structure. The analysis of the calculated parameters in relation to the local environment of the metal ions revealed that they are highly sensitive to very small changes in geometry/distances, and hence that they could be used to assist in the refinement of crystal structures. Moreover, such calculations provide a guideline as to how the NMR measurements will need to be performed, revealing that these will be very challenging.

  1. Mechanisms of mineral membrane fouling growth modulated by pulsed modes of current during electrodialysis: evidences of water splitting implications in the appearance of the amorphous phases of magnesium hydroxide and calcium carbonate.

    PubMed

    Cifuentes-Araya, Nicolás; Astudillo-Castro, Carolina; Bazinet, Laurent

    2014-07-15

    Experiments revealed the fouling nature evolutions along different electrodialysis (ED) trials, and how it disappears when current pulsation acts repetitively on the interfaces of ion-exchange membranes (IEMs). Fouling was totally controlled on the diluate side of cation-exchange membrane (CEM) by the repetitive pulsation frequency of the higher on-duty ratios applied. They created steady water splitting proton-barriers that neutralized OH(-) leakage through the membrane, decreasing the interfacial pH, and fouling of the concentrate side. The anion-exchange membrane (AEM) on the diluate side was similarly protected, but it was fouled once water splitting OH(-) generation became either intense enough or excessively weak. Interestingly, amorphous magnesium hydroxide (AMH) stemmed on the CEM-diluate side from brucite under intense water splitting OH(-) generation, and/or strong OH(-) leakage electromigration through the membrane. Water dissociation and overlimiting current regimes triggered drastic water molecule removal from crystal lattices through an accelerated cascade water splitting reaction. Also, amorphous calcium carbonate (ACC) appeared on CEM under intense water splitting reaction, and disappeared once intense OH(-) leakage was allowed by the water splitting proton-barrier dissipation. Our findings have implications for membrane fouling control, as well as for the understanding of the growth behavior of CaCO3 and Mg(OH)2 species on electromembrane interfaces.

  2. Magnesium for treatment-resistant depression: a review and hypothesis.

    PubMed

    Eby, George A; Eby, Karen L

    2010-04-01

    Sixty percent of cases of clinical depression are considered to be treatment-resistant depression (TRD). Magnesium-deficiency causes N-methyl-d-aspartate (NMDA) coupled calcium channels to be biased towards opening, causing neuronal injury and neurological dysfunction, which may appear to humans as major depression. Oral administration of magnesium to animals led to anti-depressant-like effects that were comparable to those of strong anti-depressant drugs. Cerebral spinal fluid (CSF) magnesium has been found low in treatment-resistant suicidal depression and in patients that have attempted suicide. Brain magnesium has been found low in TRD using phosphorous nuclear magnetic resonance spectroscopy, an accurate means for measuring brain magnesium. Blood and CSF magnesium do not appear well correlated with major depression. Although the first report of magnesium treatment for agitated depression was published in 1921 showing success in 220 out of 250 cases, and there are modern case reports showing rapid terminating of TRD, only a few modern clinical trials were found. A 2008 randomized clinical trial showed that magnesium was as effective as the tricyclic anti-depressant imipramine in treating depression in diabetics and without any of the side effects of imipramine. Intravenous and oral magnesium in specific protocols have been reported to rapidly terminate TRD safely and without side effects. Magnesium has been largely removed from processed foods, potentially harming the brain. Calcium, glutamate and aspartate are common food additives that may worsen affective disorders. We hypothesize that - when taken together - there is more than sufficient evidence to implicate inadequate dietary magnesium as the main cause of TRD, and that physicians should prescribe magnesium for TRD. Since inadequate brain magnesium appears to reduce serotonin levels, and since anti-depressants have been shown to have the action of raising brain magnesium, we further hypothesize that

  3. Kinetics of calcium phosphate nucleation and growth on calcite: implications for predicting the fate of dissolved phosphate species in alkaline soils.

    PubMed

    Wang, Lijun; Ruiz-Agudo, Encarnación; Putnis, Christine V; Menneken, Martina; Putnis, Andrew

    2012-01-17

    Unraveling the kinetics of calcium orthophosphate (Ca-P) precipitation and dissolution is important for our understanding of the transformation and mobility of dissolved phosphate species in soils. Here we use an in situ atomic force microscopy (AFM) coupled with a fluid reaction cell to study the interaction of phosphate-bearing solutions with calcite surfaces. We observe that the mineral surface-induced formation of Ca-P phases is initiated with the aggregation of clusters leading to the nucleation and subsequent growth of Ca-P phases on calcite, at various pH values and ionic strengths relevant to soil solution conditions. A significant decrease in the dissolved phosphate concentration occurs due to the promoted nucleation of Ca-P phases on calcite surfaces at elevated phosphate concentrations and more significantly at high salt concentrations. Also, kinetic data analyses show that low concentrations of citrate caused an increase in the nucleation rate of Ca-P phases. However, at higher concentrations of citrate, nucleation acceleration was reversed with much longer induction times to form Ca-P nuclei. These results demonstrate that the nucleation-modifying properties of small organic molecules may be scaled up to analyze Ca-P dissolution-precipitation processes that are mediated by a more complex soil environment. This in situ observation, albeit preliminary, may contribute to an improved understanding of the fate of dissolved phosphate species in diverse soil systems.

  4. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2003-01-01

    Seawater and natural brines accounted for about 60 percent of U.S. magnesium compounds production during 2002. Dead-burned and caustic-calcined magnesias were recovered from seawater by Premier Chemicals in Florida. They were also recovered from well brines in Michigan by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And they were recovered from magnesite in Nevada by Premier Chemicals.

  5. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2006-01-01

    In 2005, seawater and natural brines accounted for 51% of US magnesium compounds production. World magnesia production was estimated to be 14.5 Mt. Most of the production came from China, North Korea, Russia and Turkey. Although no specific production figures are available, Japan and the United States are estimated to account for almost one-half of the world's capacity from seawater and brines.

  6. Calcium biofortification of crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than half of the world's population is deficient in calcium (Ca), iron (Fe), iodine (I), magnesium (Mg), selenium (Se), or zinc (Zn). The consumption of plants, directly or via livestock, containing inadequate concentrations of particular minerals causes these deficiencies. Agronomic and geneti...

  7. Effect of estrogen in relation to dietary vitamin D3 and calcium on activity of intestinal alkaline phosphatase and Ca-ATPase in immature chicks.

    PubMed

    Qin, X; Klandorf, H

    1993-06-01

    The interaction between 17 beta-estradiol (E2), vitamin D3 (D3), and dietary Ca on the activities of Ca-ATPase and alkaline phosphatase (AP) was determined in the intestine of young female chicks. Chicks (n = 36) were assigned to two groups, one of which was transferred to a low Ca (0.2%) diet and the other maintained on a regular diet. One week later, each group was further divided into three subgroups and given daily injections of 0(oil), 0.25, or 0.5 mg E2/kg body wt for 14 days. E2 treatment as well as low dietary Ca significantly increased AP activity (P < 0.05), whereas the highest E2 dose decreased jejunal Ca-ATPase (P < 0.05). In a separate study, day-old chicks (n = 40) fed a purified diet supplemented with or without D3 for 24 days were divided into two subgroups and administered daily injections of either 0 or 0.25 mg estrogen 3-benzoate/kg body wt for 5 days. E2 alone or in combination with D3 failed to change Ca-ATPase activity in either the duodenum or the jejunum. However, E2 enhanced the D3-stimulated AP activity measured in the supernatant of duodenum (D3, P < 0.001; E2, P > 0.05; E2 x D3, P < 0.05) and jejunum (D3, P < 0.001; E2, P > 0.05; E2 x D3, P = 0.06). Daily injections of 0.5 mg E2/kg body wt for 6 days to 6-week-old D3-adequate chicks (n = 16) significantly increased AP activity in jejunum but not in liver and kidney (P < 0.05). In conclusion, E2 treatment enhanced the activity of intestinal AP but not Ca-ATPase. This enhancement was independent of dietary Ca, but was D3-dependent and tissue specific. The results suggest that the pubertal increase in plasma E2 can affect Ca absorption from the intestine by increasing the activity of AP.

  8. Dolomite supplementation improves bone metabolism through modulation of calcium-regulating hormone secretion in ovariectomized rats.

    PubMed

    Mizoguchi, Toshihide; Nagasawa, Sakae; Takahashi, Naoyuki; Yagasaki, Hiroshi; Ito, Michio

    2005-01-01

    Dolomite, a mineral composed of calcium magnesium carbonate (CaMg (CO3)2), is used as a food supplement that supplies calcium and magnesium. However, the effect of magnesium supplementation on bone metabolism in patients with osteoporosis is a matter of controversy. We examined the effects of daily supplementation with dolomite on calcium metabolism in ovariectomized (OVX) rats. Dolomite was administered daily to OVX rats for 9 weeks. The same amount of magnesium chloride as that supplied by the dolomite was given to OVX rats as a positive control. Histological examination revealed that ovariectomy decreased trabecular bone and increased adipose tissues in the femoral metaphysis. Dolomite or magnesium supplementation failed to improve these bone histological features. Calcium content in the femora was decreased in OVX rats. Neither calcium nor magnesium content in the femora in OVX rats was significantly increased by dolomite or magnesium administration. Urinary deoxypyridinoline excretion was significantly increased in OVX rats, and was not affected by the magnesium supplementation. Serum concentrations of magnesium were increased, and those of calcium were decreased, in OVX rats supplemented with dolomite or magnesium. However, there was a tendency toward decreased parathyroid hormone secretion and increased calcitonin secretion in OVX rats supplemented with dolomite or magnesium. Serum 1,25-dihydroxyvitamin D(3) and osteocalcin levels were significantly increased in the supplemented OVX rats. These results suggest that increased magnesium intake improves calcium metabolism in favor of increasing bone formation, through the modulation of calcium-regulating hormone secretion.

  9. Magnesium in diet

    MedlinePlus

    ... sources of magnesium: Fruits or vegetables (such as bananas, dried apricots, and avocados) Nuts (such as almonds ... Supplements, National Institutes of Health. Dietary Supplement Fact Sheet: Magnesium . ods.od.nih.gov/factsheets/Magnesium-Consumer . ...

  10. Low magnesium level

    MedlinePlus

    Low magnesium level is a condition in which the amount of magnesium in the blood is lower than normal. The medical ... that convert or use energy ( metabolism ). When the level of magnesium in the body drops below normal, ...

  11. Alkaline earth-based coordination polymers derived from a cyclotriphosphazene-functionalized hexacarboxylate

    NASA Astrophysics Data System (ADS)

    Ling, Yajing; Bai, Dongjie; Feng, Yunlong; He, Yabing

    2016-10-01

    Combination of hexakis(4-carboxylatephenoxy)cyclotriphosphazene with alkaline earth ions of increasing ionic radii (Mg2+, Ca2+ and Ba2+) under different solvothermal conditions yielded three new coordination polymers, and their crystal structures were determined by single-crystal X-ray diffraction analysis. The magnesium compound displays a three dimensional (3D) network structure constructed from the deprotonated ligand and the secondary building block Mg(COO)4, which can be rationalized as a (4,6)-connected topological net with the Schläfli symbol of (44·62)3(49·66)2. The calcium compound consists of 1D infinite "Ca-O" inorganic chains connected by the deprotonated ligands to from a 3D framework. The barium compound exhibits a 3D framework in which 1D "Ba-O" inorganic chains are connected together by the deprotonated organic linkers. Due to the semi-rigid nature, the ligand adopts distinctly different conformations in the three compounds. The metal ions' influence exerted on the final structure of the resulting coordination polymers is also discussed. When the radii of alkaline earth ions increases descending down the group from Mg(II) to Ba(II), the coordination number becomes larger and more versatile: from 6 in the magnesium compound, to 6,7 and 10 in the calcium compound, and to 8 and 9 in the barium compound, thus substantially influencing the resulting final framework structures. Also, the photophysical properties were investigated systematically, revealing that the three compounds are photoluminscent in the solid state at room temperature. This work demonstrates that although the multiplicity of conformation in the hexacarboxylate ligand based on the inorganic scaffold cyclotriphosphazene makes it difficult to predict how this ligand will form extended network, but provides unique opportunities for the formation of diverse inorganic-organic hybrids exhibiting rich structural topologies.

  12. In vitro binding capacity of zeolite A to calcium, phosphorus and magnesium in rumen fluid as influenced by changes in pH.

    PubMed

    Thilsing, T; Jørgensen, R J; Poulsen, H D

    2006-03-01

    An in vitro experiment was designed to mimic the transport of ingested zeolite A in the forestomachs and proximal part of the small intestine so as to evaluate the binding capacity of zeolite A to Ca, P and Mg as influenced by changes in pH. This was done by incubation of rumen fluid solutions with and without zeolite, as well as varying the content of Ca and/or P. The pH was lowered by addition of HCl so as to mimic abomasal conditions, followed by subsequent HCO3- addition to mimic small intestinal pH. Rumen fluid samples were taken at strategic time points in the experiment. All samples were centrifuged and the supernatant analysed for Ca, P and Mg as indicators of the amount of unbound mineral. The addition of zeolite to rumen fluid solutions reduced the amount of supernatant Ca and Mg at rumen pH, whereas the level of P was not reduced. After adding HCl, a large proportion of the zeolite-bound Ca and Mg was released, increasing supernatant Ca and Mg levels; whereas, HCl addition led to a profound drop in supernatant P in zeolite samples, indicating binding of P. A low level of supernatant P was maintained after HCO3- addition. Neutralization by HCO3- led to a zeolite-induced drop in supernatant Ca and Mg. The reduction in supernatant Ca observed in the present study concurs well with the theoretical rationale of prepartum zeolite supplementation in milk fever prevention. Furthermore, the apparent binding of P by the zeolite may also contribute because of the connection between the calcium and phosphorus homeostasis. The zeolite-induced reduction in supernatant Mg indicates that zeolite supplementation should probably be avoided in Mg-deficient herds unless Mg supplementation is initiated.

  13. Sulfur dioxide removal process with gypsum and magnesium hydroxide production

    SciTech Connect

    College, J.W.; Benson, L.B.

    1992-01-28

    This patent describes improvement in a method for removing sulfur dioxide from flue gases wherein the flue gases are contacted in a wet scrubbing unit, in the absence of any substantial amount of calcium components, with an aqueous solution of magnesium components and magnesium sulfite produced, with aqueous solution, following the contact, collected and recycled to the wet scrubber for further contact with flue gases, and subjecting a portion of the aqueous discharge from the scrubbing unit, containing magnesium sulfite, to oxidation in an oxidation unit. The improvement comprises: adding calcium sulfate to the portion of aqueous discharge containing magnesium sulfite prior to oxidation in the oxidation unit to form an oxidized aqueous effluent containing calcium sulfate solids and dissolved magnesium sulfate; passing the oxidized aqueous effluent to a regeneration tank; adding lime to the regeneration tank to precipitate gypsum from and form an aqueous magnesium hydroxide suspension in the oxidized aqueous effluent; separating the precipitated gypsum from the aqueous magnesium hydroxide suspension; and returning at least a portion of the separated precipitated gypsum to the oxidizing unit as the added calcium sulfate.

  14. Electrochemical cell with calcium anode

    DOEpatents

    Cooper, John F.; Hosmer, Pamela K.; Kelly, Benjamin E.

    1979-01-01

    An electrochemical cell comprising a calcium anode and a suitable cathode in an alkaline electrolyte consisting essentially of an aqueous solution of an hydroxide and a chloride. Specifically disclosed is a mechanically rechargeable calcium/air fuel cell with an aqueous NaOH/NaCl electrolyte.

  15. Interactions between aggressive ions and the surface of a magnesium-yttrium alloy.

    PubMed

    Johnson, Ian; Perchy, Daniel; Liu, Huinan

    2012-01-01

    Magnesium alloys possess many desirable properties for biodegradable orthopedic implants. Unfortunately, magnesium degrades too rapidly in vivo. This rapid degradation reduces the alloys' mechanical properties and increases the alkalinity of the local environment. Controlling the degradation rate and mode is an essential step in the development of magnesium based biomaterials. Accomplishing this essential step will require an improved understanding of magnesium alloy degradation. Herein, three interacting factors controlling magnesium degradation were investigated; (1) alloy composition, (2) alloy surface, (3) presence of aggressive ions in the immersion media. The magnesium-yttrium alloy was more susceptible to degradation in water than the high purity magnesium alloy. However, the polished surface magnesium-yttrium alloy had the least susceptibility to degradation in phosphate buffered saline (PBS) among all the sample compositions and surfaces.

  16. Magnesium sulphate increases lymphocyte adenosine 3':5'-cyclic monophosphate in humans.

    PubMed Central

    Von Mandach, U; Bürgi, M; Huch, R; Huch, A

    1993-01-01

    We determined the effect of i.v. magnesium sulphate, which is often combined with beta 2-adrenoceptor agonists for tocolytic therapy, on lymphocyte cyclic AMP production, extracellular magnesium and blood calcium concentrations. Sixteen healthy volunteers received i.v. magnesium sulphate 1 g h-1 over 8 h; seven volunteers also had infusion of NaCl 18 mg h-1 as control. Venous blood was taken pre- and post-infusion to determine basal lymphocyte cyclic AMP and the increase evoked by 0.1 mM isoprenaline, as well as serum and plasma concentrations of total and non-protein-bound magnesium and calcium. Following magnesium sulphate there was a significant rise in the isoprenaline-evoked increase in cyclic AMP (P < 0.05) and in the magnesium concentrations (P < 0.01) and a decrease in the free calcium concentration (P < 0.01). PMID:8385975

  17. Magnesium sulphate increases lymphocyte adenosine 3':5'-cyclic monophosphate in humans.

    PubMed

    Von Mandach, U; Bürgi, M; Huch, R; Huch, A

    1993-03-01

    We determined the effect of i.v. magnesium sulphate, which is often combined with beta 2-adrenoceptor agonists for tocolytic therapy, on lymphocyte cyclic AMP production, extracellular magnesium and blood calcium concentrations. Sixteen healthy volunteers received i.v. magnesium sulphate 1 g h-1 over 8 h; seven volunteers also had infusion of NaCl 18 mg h-1 as control. Venous blood was taken pre- and post-infusion to determine basal lymphocyte cyclic AMP and the increase evoked by 0.1 mM isoprenaline, as well as serum and plasma concentrations of total and non-protein-bound magnesium and calcium. Following magnesium sulphate there was a significant rise in the isoprenaline-evoked increase in cyclic AMP (P < 0.05) and in the magnesium concentrations (P < 0.01) and a decrease in the free calcium concentration (P < 0.01).

  18. Magnesium degradation products: effects on tissue and human metabolism.

    PubMed

    Seitz, J-M; Eifler, R; Bach, Fr-W; Maier, H J

    2014-10-01

    Owing to their mechanical properties, metallic materials present a promising solution in the field of resorbable implants. The magnesium metabolism in humans differs depending on its introduction. The natural, oral administration of magnesium via, for example, food, essentially leads to an intracellular enrichment of Mg(2+) . In contrast, introducing magnesium-rich substances or implants into the tissue results in a different decomposition behavior. Here, exposing magnesium to artificial body electrolytes resulted in the formation of the following products: magnesium hydroxide, magnesium oxide, and magnesium chloride, as well as calcium and magnesium apatites. Moreover, it can be assumed that Mg(2+) , OH(-) ions, and gaseous hydrogen are also present and result from the reaction for magnesium in an aqueous environment. With the aid of physiological metabolic processes, the organism succeeds in either excreting the above mentioned products or integrating them into the natural metabolic process. Only a burst release of these products is to be considered a problem. A multitude of general tissue effects and responses from the Mg's degradation products is considered within this review, which is not targeting specific implant classes. Furthermore, common alloying elements of magnesium and their hazardous potential in vivo are taken into account.

  19. A Study on Factors Affecting the Degradation of Magnesium and a Magnesium-Yttrium Alloy for Biomedical Applications

    PubMed Central

    Johnson, Ian; Liu, Huinan

    2013-01-01

    Controlling degradation of magnesium or its alloys in physiological saline solutions is essential for their potential applications in clinically viable implants. Rapid degradation of magnesium-based materials reduces the mechanical properties of implants prematurely and severely increases alkalinity of the local environment. Therefore, the objective of this study is to investigate the effects of three interactive factors on magnesium degradation, specifically, the addition of yttrium to form a magnesium-yttrium alloy versus pure magnesium, the metallic versus oxide surfaces, and the presence versus absence of physiological salt ions in the immersion solution. In the immersion solution of phosphate buffered saline (PBS), the magnesium-yttrium alloy with metallic surface degraded the slowest, followed by pure magnesium with metallic or oxide surfaces, and the magnesium-yttrium alloy with oxide surface degraded the fastest. However, in deionized (DI) water, the degradation rate showed a different trend. Specifically, pure magnesium with metallic or oxide surfaces degraded the slowest, followed by the magnesium-yttrium alloy with oxide surface, and the magnesium-yttrium alloy with metallic surface degraded the fastest. Interestingly, only magnesium-yttrium alloy with metallic surface degraded slower in PBS than in DI water, while all the other samples degraded faster in PBS than in DI water. Clearly, the results showed that the alloy composition, presence or absence of surface oxide layer, and presence or absence of physiological salt ions in the immersion solution all influenced the degradation rate and mode. Moreover, these three factors showed statistically significant interactions. This study revealed the complex interrelationships among these factors and their respective contributions to degradation for the first time. The results of this study not only improved our understanding of magnesium degradation in physiological environment, but also presented the key

  20. A study on factors affecting the degradation of magnesium and a magnesium-yttrium alloy for biomedical applications.

    PubMed

    Johnson, Ian; Liu, Huinan

    2013-01-01

    Controlling degradation of magnesium or its alloys in physiological saline solutions is essential for their potential applications in clinically viable implants. Rapid degradation of magnesium-based materials reduces the mechanical properties of implants prematurely and severely increases alkalinity of the local environment. Therefore, the objective of this study is to investigate the effects of three interactive factors on magnesium degradation, specifically, the addition of yttrium to form a magnesium-yttrium alloy versus pure magnesium, the metallic versus oxide surfaces, and the presence versus absence of physiological salt ions in the immersion solution. In the immersion solution of phosphate buffered saline (PBS), the magnesium-yttrium alloy with metallic surface degraded the slowest, followed by pure magnesium with metallic or oxide surfaces, and the magnesium-yttrium alloy with oxide surface degraded the fastest. However, in deionized (DI) water, the degradation rate showed a different trend. Specifically, pure magnesium with metallic or oxide surfaces degraded the slowest, followed by the magnesium-yttrium alloy with oxide surface, and the magnesium-yttrium alloy with metallic surface degraded the fastest. Interestingly, only magnesium-yttrium alloy with metallic surface degraded slower in PBS than in DI water, while all the other samples degraded faster in PBS than in DI water. Clearly, the results showed that the alloy composition, presence or absence of surface oxide layer, and presence or absence of physiological salt ions in the immersion solution all influenced the degradation rate and mode. Moreover, these three factors showed statistically significant interactions. This study revealed the complex interrelationships among these factors and their respective contributions to degradation for the first time. The results of this study not only improved our understanding of magnesium degradation in physiological environment, but also presented the key

  1. The significance of secondary interactions during alkaline earth-promoted dehydrogenation of dialkylamine-boranes.

    PubMed

    Bellham, Peter; Anker, Mathew D; Hill, Michael S; Kociok-Köhn, Gabriele; Mahon, Mary F

    2016-09-21

    Reactions of anilidoimine magnesium n-butyl and calcium bis(trimethylsilyl)amide derivatives with Me2NH·BH3 at 25 °C resulted in the isolation of complexes containing [NMe2BH2NMe2BH3](-) and [NMe2BH3](-) anions respectively. Although onward reaction of the calcium species at 30 °C with a further equivalent of Me2NH·BH3 provided ca. 90% conversion of the coordinated dimethylamidoborane anion to [NMe2BH2NMe2BH3](-), this process also resulted in significant (ca. 25%) levels of competitive protonation of the anilidoimine spectator ligand. A similar reaction performed between a previously reported β-diketiminato calcium dimethylamidoborane and Me2NH·BH3, however, provided clean conversion to a structurally characterised calcium [NMe2BH2NMe2BH3](-) complex. Reaction of a more sterically congested β-diketiminato magnesium n-butyl reagent with Me2NH·BH3 has allowed the isolation of a magnesium derivative of the [NMe2BH3](-) anion. The thermal stability of these compounds as well as previously reported magnesium and calcium amidoborane species indicate, in partial agreement with a recent DFT study, that all of these compounds are resistant to the β- and δ-hydride elimination reactions that have previously been implicated as the key B-N bond-forming and dehydrogenative steps in the group 2-catalysed dehydrocoupling of Me2NH·BH3. In contrast to these observations, addition of stoichiometric quantities of Me2NH·BH3 to the various isolated group 2 amidoborane species was found to result in facile elimination of the cyclic borazane [Me2N-BH2]2 which occurs with regeneration of the metallated amidoborane. On this basis, we suggest that the dehydrocoupling of Me2NH·BH3 at group 2 centres takes place as a sequence of concerted proton-assisted steps during which B-H and N-H bond breaking plays an equally prominent role, with the efficacy of boron hydride protonolysis dictated by the relative polarising influence of the B-H to Mg/Ca interactions. Furthermore, we propose

  2. Mechanisms of magnesium-induced vasodilation in cerebral penetrating arterioles.

    PubMed

    Murata, Takahiro; Dietrich, Hans H; Horiuchi, Tetsuyoshi; Hongo, Kazuhiro; Dacey, Ralph G

    2016-06-01

    We investigated in cerebral penetrating arterioles the signaling mechanisms and dose-dependency of extracellular magnesium-induced vasodilation and also its vasodilatory effects in vessels preconstricted with agonists associated with delayed cerebral vasospasm following SAH. Male rat penetrating arterioles were cannulated. Their internal diameters were monitored. To investigate mechanisms of magnesium-induced vasodilation, inhibitors of endothelial function, potassium channels and endothelial impairment were tested. To simulate cerebral vasospasm we applied several spasmogenic agonists. Increased extracellular magnesium concentration produced concentration-dependent vasodilation, which was partially attenuated by non-specific calcium-sensitive potassium channel inhibitor tetraethylammonium, but not by other potassium channel inhibitors. Neither the nitric oxide synthase inhibitor L-NNA nor endothelial impairment induced by air embolism reduced the dilation. Although the magnesium-induced vasodilation was slightly attenuated by the spasmogen ET-1, neither application of PF2α nor TXA2 analog effect the vasodilation. Magnesium induced a concentration- and smooth muscle cell-dependent dilation in cerebral penetrating arterioles. Calcium-sensitive potassium channels of smooth muscle cells may play a key role in magnesium-induced vasodilation. Magnesium also dilated endothelium-impaired vessels as well as vessels preconstricted with spasmogenic agonists. These results provide a fundamental background for the clinical use of magnesium, especially in treatment against delayed cerebral ischemia or vasospasm following SAH.

  3. DISTILLATION OF CALCIUM

    DOEpatents

    Barton, J.

    1954-07-27

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

  4. Complexometric Determination of Calcium

    NASA Astrophysics Data System (ADS)

    Nielsen, S. Suzanne

    Ethylenediaminetetraacetate (EDTA) complexes with numerous mineral ions, including calcium and magnesium. This reaction can be used to determine the amount of these minerals in a sample by a complexometric titration. Endpoints in the titration are detected using indicators that change color when they complex with mineral ions. Calmagite and eriochrome black T (EBT) are such indicators that change from blue to pink when they complex with calcium and magnesium. In the titration of a mineral-containing solution with EDTA, the solution turns from pink to blue at the endpoint with either indicator. The pH affects a complexometric EDTA titration in several ways, and must be carefully controlled. A major application of EDTA titration is testing the hardness of water, for which the method described is an official one (Standard Methods for the Examination of Water and Wastewater, Method 2340C; AOAC Method 920.196).

  5. Simultaneous determination of arsenic, cadmium, calcium, chromium, cobalt, copper, iron, lead, magnesium, manganese, molybdenum, nickel, selenium, and zinc in fertilizers by microwave acid digestion and inductively coupled plasma-optical emission spectrometry detection: single-laboratory validation of a modification and extension of AOAC 2006.03.

    PubMed

    Webb, Sharon; Bartos, James; Boles, Rhonda; Hasty, Elaine; Thuotte, Ethel; Thiex, Nancy J

    2014-01-01

    A single-laboratory validation study was conducted for the simultaneous determination of arsenic, cadmium, calcium, cobalt, copper, chromium, iron, lead, magnesium, manganese, molybdenum, nickel, selenium, and zinc in all major types of commercial fertilizer products by microwave digestion and inductively coupled plasma-optical emission spectroscopy analysis. This validation study proposes an extension and modification of AOAC 2006.03. The extension is the inclusion of calcium, copper, iron, magnesium, manganese, and zinc, and the modification is incorporation of hydrochloric acid in the digestion system. This dual acid digestion utilizes both hydrochloric and nitric acids in a 3 to 9 mL volume ratio/100 mL. In addition to 15 of the 30 original validation materials used in the 2006.03 collaborative study, National Institute of Standards and Technology Standard Reference Material 695 and Magruder 2009-06 were incorporated as accuracy materials. The main benefits of this proposed method are a significant increase in laboratory efficiency when compared to the use of both AOAC Methods 965.09 and 2006.03 to achieve the same objective and an enhanced recovery of several metals.

  6. Alkaline and alkaline earth metal phosphate halides and phosphors

    DOEpatents

    Lyons, Robert Joseph; Setlur, Anant Achyut; Cleaver, Robert John

    2012-11-13

    Compounds, phosphor materials and apparatus related to nacaphite family of materials are presented. Potassium and rubidium based nacaphite family compounds and phosphors designed by doping divalent rare earth elements in the sites of alkaline earth metals in the nacaphite material families are descried. An apparatus comprising the phosphors based on the nacaphite family materials are presented herein. The compounds presented is of formula A.sub.2B.sub.1-yR.sub.yPO.sub.4X where the elements A, B, R, X and suffix y are defined such that A is potassium, rubidium, or a combination of potassium and rubidium and B is calcium, strontium, barium, or a combination of any of calcium, strontium and barium. X is fluorine, chlorine, or a combination of fluorine and chlorine, R is europium, samarium, ytterbium, or a combination of any of europium, samarium, and ytterbium, and y ranges from 0 to about 0.1.

  7. Calcium supplements

    MedlinePlus

    ... TYPES OF CALCIUM SUPPLEMENTS Forms of calcium include: Calcium carbonate: Over-the-counter (OTC) antacid products, such as Tums and Rolaids, contain calcium carbonate. These sources of calcium do not cost much. ...

  8. Choline Magnesium Trisalicylate

    MedlinePlus

    Choline magnesium trisalicylate is used to relieve the pain, tenderness, inflammation (swelling), and stiffness caused by arthritis ... painful shoulder. It is also used to relieve pain and lower fever. Choline magnesium trisalicylate is in ...

  9. Preparation and preliminary cytocompatibility of magnesium doped apatite cement with degradability for bone regeneration.

    PubMed

    Lu, Jingxiong; Wei, Jie; Yan, Yonggang; Li, Hong; Jia, Junfeng; Wei, Shicheng; Guo, Han; Xiao, Tiqiao; Liu, Changsheng

    2011-03-01

    In the present study, we fabricated magnesium doped apatite cement (md-AC) with rapid self-setting characteristic by adding the mixed powders of magnesium oxide and calcium dihydrogen phosphate (MO-CDP) into hydroxyapatite cement (HAC). The results revealed that the md-AC with 50 wt% MO-CDP could set within 6 min and the compression strength could reach 51 MPa after setting for 1 h, indicating that the md-AC had highly initial mechanical strength. The degradability of the md-AC in Tris-HCl solution increased with the increase of MO-CDP amount, and the weight loss ratio of md-AC with 50 wt% MO-CDP was 57.5 wt% after soaked for 12 weeks. Newly flake-like apatite could be deposited on the md-AC surfaces after soaked in simulated body fluid (SBF) for 7 days. Cell proliferation ratio of MG(63) cells on md-AC was obviously higher than that of HAC on days 4 and 7. The cells with normal phenotype spread well on the md-AC surfaces and attached intimately with the substrate, and alkaline phosphatase (ALP) activity of the cells on md-AC significantly improved compared with HAC on day 7. The results demonstrate that the md-AC has a good ability to support cell proliferation and differentiation, and indicate a good cytocompatibility.

  10. Atomic hydrogen in. gamma. -irradiated hydroxides of alkaline-earth elements

    SciTech Connect

    Spitsyn, V.I.; Yurik, T.K.; Barsova, L.I.

    1982-04-01

    Atomic hydrogen is an important intermediate product formed in the radiolysis of compounds containing X-H bonds. H atoms have been detected in irradiated matrices of H/sub 2/ and inert gases at 4/sup 0/K, in irradiated ice and frozen solutions of acids in irradiated salts and in other systems. Here results are presented from a study of the ESR spectra of H atoms generated in polycrystalline hydroxides of alkaline-earth elements that have been ..gamma..-irradiated at 77/sup 0/K, after preliminary treatment at various temperatures. For the first time stabilization of atomic hydrogen in ..gamma..-irradiated polycrystalline alkaline-earth element hydroxides has been detected. Depending on the degree of dehydroxylation, several types of hydrogen atoms may be stabilized in the hydroxides, these hydrogen atoms having different radiospectroscopic parameters. In the magnesium-calcium-strontium-barium hydroxide series, a regular decrease has been found in the hfi constants for H atoms with the cations in the immediate surroundings. A direct proportionality has been found between the parameters ..delta..A/A/sub 0/ and the polarizability of the cation.

  11. Magnesium and Space Flight

    PubMed Central

    Smith, Scott M.; Zwart, Sara R.

    2015-01-01

    Magnesium is an essential nutrient for muscle, cardiovascular, and bone health on Earth, and during space flight. We sought to evaluate magnesium status in 43 astronauts (34 male, 9 female; 47 ± 5 years old, mean ± SD) before, during, and after 4–6-month space missions. We also studied individuals participating in a ground analog of space flight (head-down-tilt bed rest; n = 27 (17 male, 10 female), 35 ± 7 years old). We evaluated serum concentration and 24-h urinary excretion of magnesium, along with estimates of tissue magnesium status from sublingual cells. Serum magnesium increased late in flight, while urinary magnesium excretion was higher over the course of 180-day space missions. Urinary magnesium increased during flight but decreased significantly at landing. Neither serum nor urinary magnesium changed during bed rest. For flight and bed rest, significant correlations existed between the area under the curve of serum and urinary magnesium and the change in total body bone mineral content. Tissue magnesium concentration was unchanged after flight and bed rest. Increased excretion of magnesium is likely partially from bone and partially from diet, but importantly, it does not come at the expense of muscle tissue stores. While further study is needed to better understand the implications of these findings for longer space exploration missions, magnesium homeostasis and tissue status seem well maintained during 4–6-month space missions. PMID:26670248

  12. Magnesium and Space Flight.

    PubMed

    Smith, Scott M; Zwart, Sara R

    2015-12-08

    Magnesium is an essential nutrient for muscle, cardiovascular, and bone health on Earth, and during space flight. We sought to evaluate magnesium status in 43 astronauts (34 male, 9 female; 47 ± 5 years old, mean ± SD) before, during, and after 4-6-month space missions. We also studied individuals participating in a ground analog of space flight (head-down-tilt bed rest; n = 27 (17 male, 10 female), 35 ± 7 years old). We evaluated serum concentration and 24-h urinary excretion of magnesium, along with estimates of tissue magnesium status from sublingual cells. Serum magnesium increased late in flight, while urinary magnesium excretion was higher over the course of 180-day space missions. Urinary magnesium increased during flight but decreased significantly at landing. Neither serum nor urinary magnesium changed during bed rest. For flight and bed rest, significant correlations existed between the area under the curve of serum and urinary magnesium and the change in total body bone mineral content. Tissue magnesium concentration was unchanged after flight and bed rest. Increased excretion of magnesium is likely partially from bone and partially from diet, but importantly, it does not come at the expense of muscle tissue stores. While further study is needed to better understand the implications of these findings for longer space exploration missions, magnesium homeostasis and tissue status seem well maintained during 4-6-month space missions.

  13. REGENERATION OF FISSION-PRODUCT-CONTAINING MAGNESIUM-THORIUM ALLOYS

    DOEpatents

    Chiotti, P.

    1964-02-01

    A process of regenerating a magnesium-thorium alloy contaminated with fission products, protactinium, and uranium is presented. A molten mixture of KCl--LiCl-MgCl/sub 2/ is added to the molten alloy whereby the alkali, alkaline parth, and rare earth fission products (including yttrium) and some of the thorium and uranium are chlorinated and

  14. Thin-layer chromatographie separation of alkaline earth metals on diethylaminoethyl cellulose.

    PubMed

    Ishida, K

    1969-12-01

    Thin-layer Chromatographic behaviour of magnesium, calcium, strontium and barium on diethylaminoethyl cellulose has been investigated in methanol-nitric acid mixtures. R(f) values are in the order magnesium > calcium > strontium > barium. The differences in R(f) values are large enough to allow good separations of the four metal ions from each other. The best separation is obtained by the ascending technique with methanol-8M nitric acid (20:1, v v ).

  15. Alkaline earth metal catalysts for asymmetric reactions.

    PubMed

    Kobayashi, Shū; Yamashita, Yasuhiro

    2011-01-18

    The group 2 alkaline earth metals calcium (Ca), strontium (Sr), and barium (Ba) are among the most common elements on Earth, abundant in both the sea and the Earth's crust. Although they are familiar in our daily lives, their application to organic synthesis has, so far, been limited. Some particularly useful properties of these elements include (i) low electronegativity, (ii) a stable oxidation state of +2, meaning that they can potentially form two covalent bonds with anions, and (iii) the ability to occupy a variety of coordination sites due to their large ionic radius. Furthermore, the alkaline earth metals, found between the group 1 and group 3 elements, show mild but significant Lewis acidity, which can be harnessed to control coordinative molecules via a Lewis acid-base interaction. Taken together, these characteristics make the metals Ca, Sr, and Ba very promising components of highly functionalized acid-base catalysts. In this Account, we describe the development of chiral alkaline earth metal catalysts for asymmetric carbon-carbon bond-forming reactions. Recently prepared chiral alkaline earth metal complexes have shown high diastereo- and enantioselectivities in fundamental and important chemical transformations. We chose chiral bisoxazoline (Box) derivatives bearing a methylene tether as a ligand for chiral modification. These molecules are very useful because they can covalently coordinate to alkaline earth metals in a bidentate fashion through deprotonation of the tether portion. It was found that chiral calcium-Box complexes could successfully promote catalytic asymmetric 1,4-addition and [3 + 2] cycloaddition reactions with high diastereo- and enantioselectivities. Both the calcium-Box complexes and chiral strontium-bis-sulfonamide and chiral barium-BINOLate complexes could catalyze asymmetric 1,4-addition reactions with high enantioselectivities. Furthermore, we designed a calcium-neutral coordinative ligand complex as a new type of chiral alkaline

  16. The bioavailability of magnesium in spinach and the effect of oxalic acid on magnesium utilization examined in diets of magnesium-deficient rats.

    PubMed

    Kikunaga, S; Ishii, H; Takahashi, M

    1995-12-01

    Spinach was evaluated for its bioavailability of magnesium in the experiment with magnesium-deficient rats. The effect of oxalic acid on absorption of dietary magnesium was also examined in the same experiment. After there were significant differences in the body weight of the rats between the control group and the magnesium-deficient group, and after the number of dead rats increased, the magnesium-deficient rats were divided into six groups. They were pair-fed for 8 days on the magnesium-deficient diet, magnesium-deficient diet supplemented with raw powdered spinach (R-sp), boiled powdered spinach (B-sp), or fried powdered spinach (F-sp), control diet supplemented with oxalic acid (Ox-C), and control diet (+Mg). On the 10th day, there was no significant difference in the food intake of the rats between the control group and magnesium-deficient group. However, the body weight, and body weight gain of the rats increased more significantly in the control group than in those of the magnesium-deficient group. Also, the contents of calcium and phosphorus in the liver and kidneys, and serum calcium content increased significantly in the magnesium-deficient rats compared with those of the control rats. However, the serum magnesium content decreased significantly in the magnesium-deficient rats. An especially large amount of calcium was accumulated in the kidneys of the magnesium-deficient rats. At the end of the experimental period, there were no significant differences in the food intake, body weight and body weight gain of the rats among the control group and each of the spinach-added groups. The body weight and body weight gain of the Ox-C rats decreased significantly in comparison with those of the control group and each of the spinach-added groups. Although, there were no significant differences in the concentrations of serum minerals (Mg, Ca and P) among each of the groups, kidney magnesium, calcium and phosphorus, and liver magnesium and phosphorus were

  17. Superplasticity in Thermomechanically Processed High Magnesium Aluminum-Magnesium Alloys.

    DTIC Science & Technology

    1984-03-01

    California DTIC EECTE JL I 1984 THESIS SUPERPLASTICITY IN THERMOMECHANICALLY PROCESSED HIGH MAGNESIUM ALUMINUM-MAGNESIUM ALLOYS C:L by CD) John J. Becker...High Magnesium Aluminum- March 1984 Magnesium Alloys S. PERFORMING ORG. REPORT NUMBER 7. AUTHOR(@) S. CONTRACT OR GRANT NUMBER(&) John J. Becker 9...magnesium, aluminum-magnesium alloys were investigated. The thermomechanical processing itself included warm rolling at 300°C to 94% reduction

  18. Lithium-aluminum-magnesium electrode composition

    DOEpatents

    Melendres, Carlos A.; Siegel, Stanley

    1978-01-01

    A negative electrode composition is presented for use in a secondary, high-temperature electrochemical cell. The cell also includes a molten salt electrolyte of alkali metal halides or alkaline earth metal halides and a positive electrode including a chalcogen or a metal chalcogenide as the active electrode material. The negative electrode composition includes up to 50 atom percent lithium as the active electrode constituent and a magnesium-aluminum alloy as a structural matrix. Various binary and ternary intermetallic phases of lithium, magnesium, and aluminum are formed but the electrode composition in both its charged and discharged state remains substantially free of the alpha lithium-aluminum phase and exhibits good structural integrity.

  19. The alkaline earth intercalates of molybdenum disulfide

    NASA Technical Reports Server (NTRS)

    Somoano, R. B.; Hadek, V.; Rembaum, A.; Samson, S.; Woollam, J. A.

    1975-01-01

    Molybdenum disulfide has been intercalated with calcium and strontium by means of the liquid ammonia technique. Chemical, X-ray, and superconductivity data are presented. The X-ray data reveal a lowering of crystal symmetry and increase of complexity of the structure upon intercalation with the alkaline earth metals. The Ca and Sr intercalates start to superconduct at 4 and 5.6 K, respectively, and show considerable anisotropy regarding the critical magnetic field.

  20. Alkaline earth metal fluxes for the growth of single crystal oxides

    NASA Astrophysics Data System (ADS)

    Ramirez, Daniel

    Oxide ceramics are materials with a wide range of properties. Insulators are most common, however semiconductors, strongly correlated electron materials, and even superconductors are all relevant oxide materials. Here we seek to synthesize novel oxide single crystal phases and study their properties using an alkaline earth metal flux technique. The specific flux techniques are new, and we will seek to understand the capabilities of these fluxes as a novel synthesis tool. The use of a barium metal flux to grow single crystal oxides is rather counterintuitive, but is exemplified further with the growth of europium monoxide (Fm3¯m #225, Z = 4). Eu1-xBaxO single crystals (x = 0.01 - 0.25) are grown and studied for their ferromagnetic properties. A new oxide phase Ba2Eu2P2O (P4/mbm #127, Z = 2) has also been synthesized from the same method, and may potentially be studied as a ferromagnetic semiconductor based on preliminary observations. Other examples of single crystal oxide phases grown from barium metal flux includes Ba2TeO (P4/nmm #129, Z = 2), BaLn2O4 (Ln = La - Lu) (Pnma #62, Z = 4), and Ba3Yb2O 5Te (P4/mmm #123 Z = 1). The new crystal phases Ba3Ln2O5Cl 2 (Ln = Sm - Lu, Y) are synthesized using a reactive barium metal flux. Single crystal x-ray diffraction is used to determine their structures with space group (I4/mmm #139, Z = 2) related to the Ruddlesden-Popper structure type. The unit cell dimensions range from a = 4.46(6) A and c = 24.87(6) A for Ba3Gd2O5Cl2 to a = 4.35(6) A and c = 24.57(6) A for Ba3Lu2O 5Cl2 with the dimensions following the expected lanthanide contraction trends. The magnetic properties of these materials are studied and related to their structures. The use of alkaline earth fluxes such as magnesium or calcium based fluxes are also briefly considered for their capabilities to produce novel mixed anion phases. A calcium flux is shown to produce the novel semimetals Ca 4TeOH4 and Ca3Ca1-xEuxTeOH 4 (I4/mmm #139, Z = 2), and highly reducing

  1. Magnesium therapy in a hypocalcemic African grey parrot (Psittacus erithacus).

    PubMed

    Kirchgessner, Megan S; Tully, Thomas N; Nevarez, Javier; Sanchez-Migallon Guzman, David; Acierno, Mark J

    2012-03-01

    Hypocalcemic-induced seizure activity is a clinical entity that is commonly diagnosed in neurologic African grey parrots (Psittacus erithacus). Plasma calcium levels are typically less than 6.0 mg/dL at the time of seizure activity, and although the underlying cause of the hypocalcemia has not yet been determined, many theories have been proposed. An African grey parrot that had been fed a seed diet for 8 years was presented with hypocalcemia and seizures and exhibited precipitously declining plasma calcium levels, despite aggressive calcium and vitamin A, D, and E supplementation for 4 days. Baseline magnesium levels in this parrot were determined to be 1.9 mg/dL; therefore, magnesium sulfate was administered at a dose of 20 mg/kg IM once. Twenty-four hours after supplementation, the plasma magnesium level was 3.3 mg/dL, and no further seizure activity was observed. We believe that a primary dietary magnesium deficiency may have been present in this African grey parrot, similar to a syndrome in leghorn chicks, which is frequently characterized by progressive hypocalcemia that is unable to be corrected by calcium supplementation alone.

  2. A novel acidic matrix protein, PfN44, stabilizes magnesium calcite to inhibit the crystallization of aragonite.

    PubMed

    Pan, Cong; Fang, Dong; Xu, Guangrui; Liang, Jian; Zhang, Guiyou; Wang, Hongzhong; Xie, Liping; Zhang, Rongqing

    2014-01-31

    Magnesium is widely used to control calcium carbonate deposition in the shell of pearl oysters. Matrix proteins in the shell are responsible for nucleation and growth of calcium carbonate crystals. However, there is no direct evidence supporting a connection between matrix proteins and magnesium. Here, we identified a novel acidic matrix protein named PfN44 that affected aragonite formation in the shell of the pearl oyster Pinctada fucata. Using immunogold labeling assays, we found PfN44 in both the nacreous and prismatic layers. In shell repair, PfN44 was repressed, whereas other matrix proteins were up-regulated. Disturbing the function of PfN44 by RNAi led to the deposition of porous nacreous tablets with overgrowth of crystals in the nacreous layer. By in vitro circular dichroism spectra and fluorescence quenching, we found that PfN44 bound to both calcium and magnesium with a stronger affinity for magnesium. During in vitro calcium carbonate crystallization and calcification of amorphous calcium carbonate, PfN44 regulated the magnesium content of crystalline carbonate polymorphs and stabilized magnesium calcite to inhibit aragonite deposition. Taken together, our results suggested that by stabilizing magnesium calcite to inhibit aragonite deposition, PfN44 participated in P. fucata shell formation. These observations extend our understanding of the connections between matrix proteins and magnesium.

  3. A Novel Acidic Matrix Protein, PfN44, Stabilizes Magnesium Calcite to Inhibit the Crystallization of Aragonite*

    PubMed Central

    Pan, Cong; Fang, Dong; Xu, Guangrui; Liang, Jian; Zhang, Guiyou; Wang, Hongzhong; Xie, Liping; Zhang, Rongqing

    2014-01-01

    Magnesium is widely used to control calcium carbonate deposition in the shell of pearl oysters. Matrix proteins in the shell are responsible for nucleation and growth of calcium carbonate crystals. However, there is no direct evidence supporting a connection between matrix proteins and magnesium. Here, we identified a novel acidic matrix protein named PfN44 that affected aragonite formation in the shell of the pearl oyster Pinctada fucata. Using immunogold labeling assays, we found PfN44 in both the nacreous and prismatic layers. In shell repair, PfN44 was repressed, whereas other matrix proteins were up-regulated. Disturbing the function of PfN44 by RNAi led to the deposition of porous nacreous tablets with overgrowth of crystals in the nacreous layer. By in vitro circular dichroism spectra and fluorescence quenching, we found that PfN44 bound to both calcium and magnesium with a stronger affinity for magnesium. During in vitro calcium carbonate crystallization and calcification of amorphous calcium carbonate, PfN44 regulated the magnesium content of crystalline carbonate polymorphs and stabilized magnesium calcite to inhibit aragonite deposition. Taken together, our results suggested that by stabilizing magnesium calcite to inhibit aragonite deposition, PfN44 participated in P. fucata shell formation. These observations extend our understanding of the connections between matrix proteins and magnesium. PMID:24302723

  4. Comparison of Dolomite Crystal Structure, Calcinations Dolomite and Magnesium Hydroxide in Partial Calcinations and Slaking Process

    NASA Astrophysics Data System (ADS)

    Sulistiyono, E.; Firdiyono, F.; Natasha, NC; Amalia, Y.

    2017-02-01

    Dolomite is a mineral that consists of calcium carbonate and magnesium carbonate with various mole ratio depend on the formation of mineral source. Recently, Utilization of dolomite only used as raw material for fertilizer and building materials, so that the enhancement of its added value becomes low. If the components in dolomite can be separated, magnesium carbonate and calcium carbonate will be produced then provide high added value. To separate these two components in dolomite is through partial calcinations followed by slaking process. The purpose of this paper is to prove that the partial calcinations can be used as a fundamental process for calcium and magnesium separation process in dolomite. SEM-EDX and XRD analysis proved that partial calcinations at 675°C for 6 hours is able to produce magnesium oxide (MgO) and calcium oxide (CaO). Then sea water was added to calcinations product so magnesium hydroxide and calcium carbonate that easily separated by sea water. The weakness of partial calcinations process at 675°C and processing time 2 hours is the dolomite has not perfectly reacted yet. XRD analysis showed that MgCO3. CaCO3 compounds still exist, so there is a possibility that magnesium was not fetched after the separation process.

  5. Physicochemical action of potassium-magnesium citrate in nephrolithiasis

    NASA Technical Reports Server (NTRS)

    Pak, C. Y.; Koenig, K.; Khan, R.; Haynes, S.; Padalino, P.

    1992-01-01

    Effect of potassium-magnesium citrate on urinary biochemistry and crystallization of stone-forming salts was compared with that of potassium citrate at same dose of potassium in five normal subjects and five patients with calcium nephrolithiasis. Compared to the placebo phase, urinary pH rose significantly from 6.06 +/- 0.27 to 6.48 +/- 0.36 (mean +/- SD, p less than 0.0167) during treatment with potassium citrate (50 mEq/day for 7 days) and to 6.68 +/- 0.31 during therapy with potassium-magnesium citrate (containing 49 mEq K, 24.5 mEq Mg, and 73.5 mEq citrate per day). Urinary pH was significantly higher during potassium-magnesium citrate than during potassium citrate therapy. Thus, the amount of undissociated uric acid declined from 118 +/- 61 mg/day during the placebo phase to 68 +/- 54 mg/day during potassium citrate treatment and, more prominently, to 41 +/- 46 mg/day during potassium-magnesium citrate therapy. Urinary magnesium rose significantly from 102 +/- 25 to 146 +/- 37 mg/day during potassium-magnesium citrate therapy but not during potassium citrate therapy. Urinary citrate rose more prominently during potassium-magnesium citrate therapy (to 1027 +/- 478 mg/day from 638 +/- 252 mg/day) than during potassium citrate treatment (to 932 +/- 297 mg/day). Consequently, urinary saturation (activity product) of calcium oxalate declined significantly (from 1.49 x 10(-8) to 1.03 x 10(-8) M2) during potassium-magnesium citrate therapy and marginally (to 1.14 x 10(-8) M2) during potassium citrate therapy.(ABSTRACT TRUNCATED AT 250 WORDS).

  6. Anodes for alkaline electrolysis

    DOEpatents

    Soloveichik, Grigorii Lev

    2011-02-01

    A method of making an anode for alkaline electrolysis cells includes adsorption of precursor material on a carbonaceous material, conversion of the precursor material to hydroxide form and conversion of precursor material from hydroxide form to oxy-hydroxide form within the alkaline electrolysis cell.

  7. Impurities Removal in Seawater to Optimize the Magnesium Extraction

    NASA Astrophysics Data System (ADS)

    Natasha, N. C.; Firdiyono, F.; Sulistiyono, E.

    2017-02-01

    Magnesium extraction from seawater is promising way because magnesium is the second abundant element in seawater and Indonesia has the second longest coastline in the world. To optimize the magnesium extraction, the impurities in seawater need to be eliminated. Evaporation and dissolving process were used in this research to remove the impurities especially calcium in seawater. Seawater which has been evaporated from 100 ml to 50 ml was dissolved with variations solution such as oxalic acid and ammonium bicarbonate. The solution concentration is 100 g/l and it variations are 2 ml, 4 ml, 6 ml, 8 ml, 10 ml, 20 ml, 30 ml, 40 ml and 50 ml. This step will produce precipitate and filtrate then it will be analysed to find out the result of this process. The precipitate was analysed by X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) but the filtrate was analysed by Inductively Coupled Plasma (ICP). XRD analysis shows that calcium oxalate and calcium carbonate were formed and ICP analysis shows that the remaining calcium in seawater using oxalic acid is about 0.01% and sodium 0.14% but when using ammonium bicarbonate the remaining calcium is 2.5% and sodium still more than 90%. The results show that both oxalic acid and ammonium bicarbonate can remove the impurities but when using oxalic acid, not only the impurities but also magnesium was precipitated. The conclusion of this research is the best solution to remove the impurities in seawater without precipitate the magnesium is using ammonium bicarbonate.

  8. Method for production of magnesium

    DOEpatents

    Diaz, A.F.; Howard, J.B.; Modestino, A.J.; Peters, W.A.

    1998-07-21

    A continuous process for the production of elemental magnesium is described. Magnesium is made from magnesium oxide and a light hydrocarbon gas. In the process, a feed stream of the magnesium oxide and gas is continuously fed into a reaction zone. There the magnesium oxide and gas are reacted at a temperature of about 1400 C or greater in the reaction zone to provide a continuous product stream of reaction products, which include elemental magnesium. The product stream is continuously quenched after leaving the reaction zone, and the elemental magnesium is separated from other reaction products. 12 figs.

  9. Method for production of magnesium

    DOEpatents

    Diaz, Alexander F.; Howard, Jack B.; Modestino, Anthony J.; Peters, William A.

    1998-01-01

    A continuous process for the production of elemental magnesium is described. Magnesium is made from magnesium oxide and a light hydrocarbon gas. In the process, a feed stream of the magnesium oxide and gas is continuously fed into a reaction zone. There the magnesium oxide and gas are reacted at a temperature of about 1400.degree. C. or greater in the reaction zone to provide a continuous product stream of reaction products, which include elemental magnesium. The product stream is continuously quenched after leaving the reaction zone, and the elemental magnesium is separated from other reaction products.

  10. Efficacy of calcium glycerophosphate vs conventional mineral salts for total parenteral nutrition in low-birth-weight infants: a randomized clinical trial.

    PubMed

    Hanning, R M; Atkinson, S A; Whyte, R K

    1991-11-01

    To test the efficacy of calcium glycerophosphate (CaGlyP) vs the conventional mineral salts, calcium gluconate plus KH2PO4 + K2HPO4 (CaGluc + P), in promoting mineral retention, 72-h mineral balance, biochemical status, net acid excretion, and growth were assessed in 16 low-birth-weight infants receiving total parenteral nutrition (TPN) containing approximately 1.5 mmol Ca and P.kg-1.d-1 for 5 d. Net retentions of calcium (1.2 +/- 0.2 vs 1.0 +/- 0.2 mmol.kg-1.d-1, means +/- SD) and phosphorus (1.1 +/- 0.3 vs 0.8 +/- 0.3 mmol.kg-1.d-1) from CaGluc + P vs CaGlyP, respectively, were similar, as were retentions of magnesium and sodium, urinary pH, and net acid excretion. Plasma ionized calcium, inorganic phosphorus, alkaline phosphatase, and osteocalcin were normal and not different between groups. CaGlyP is as effective as CaGluc + P in promoting mineral retention and normal mineral homeostasis. However, at intakes of less than or equal to 1.5 mmol Ca and P.kg-1.d-1 from either mineral salt, retention represented only 60% and 45%, respectively, of the predicted intrauterine accretion for calcium and phosphorus. Larger intakes permitted by the more-soluble CaGlyP may be desirable for infants receiving TPN.

  11. Thermodynamic criteria for the removal of impurities from end-of-life magnesium alloys by evaporation and flux treatment

    PubMed Central

    Hiraki, Takehito; Takeda, Osamu; Nakajima, Kenichi; Matsubae, Kazuyo; Nakamura, Shinichiro; Nagasaka, Tetsuya

    2011-01-01

    In this paper, the possibility of removing impurities during magnesium recycling with pyrometallurgical techniques has been evaluated by using a thermodynamic analysis. For 25 different elements that are likely to be contained in industrial magnesium alloys, the equilibrium distribution ratios between the metal, slag and gas phases in the magnesium remelting process were calculated assuming binary systems of magnesium and an impurity element. It was found that calcium, gadolinium, lithium, ytterbium and yttrium can be removed from the remelted end-of-life (EoL) magnesium products by oxidization. Calcium, cerium, gadolinium, lanthanum, lithium, plutonium, sodium, strontium and yttrium can be removed by chlorination with a salt flux. However, the other elements contained in magnesium alloy scrap are scarcely removed and this may contribute toward future contamination problems. The third technological option for the recycling of EoL magnesium products is magnesium recovery by a distillation process. Based on thermodynamic considerations, it is predicted that high-purity magnesium can be recovered through distillation because of its high vapor pressure, yet there is a limit on recoverability that depends on the equilibrium vapor pressure of the alloying elements and the large energy consumption. Therefore, the sustainable recycling of EoL magnesium products should be an important consideration in the design of advanced magnesium alloys or the development of new refining processes. PMID:27877407

  12. Thermodynamic criteria for the removal of impurities from end-of-life magnesium alloys by evaporation and flux treatment

    NASA Astrophysics Data System (ADS)

    Hiraki, Takehito; Takeda, Osamu; Nakajima, Kenichi; Matsubae, Kazuyo; Nakamura, Shinichiro; Nagasaka, Tetsuya

    2011-06-01

    In this paper, the possibility of removing impurities during magnesium recycling with pyrometallurgical techniques has been evaluated by using a thermodynamic analysis. For 25 different elements that are likely to be contained in industrial magnesium alloys, the equilibrium distribution ratios between the metal, slag and gas phases in the magnesium remelting process were calculated assuming binary systems of magnesium and an impurity element. It was found that calcium, gadolinium, lithium, ytterbium and yttrium can be removed from the remelted end-of-life (EoL) magnesium products by oxidization. Calcium, cerium, gadolinium, lanthanum, lithium, plutonium, sodium, strontium and yttrium can be removed by chlorination with a salt flux. However, the other elements contained in magnesium alloy scrap are scarcely removed and this may contribute toward future contamination problems. The third technological option for the recycling of EoL magnesium products is magnesium recovery by a distillation process. Based on thermodynamic considerations, it is predicted that high-purity magnesium can be recovered through distillation because of its high vapor pressure, yet there is a limit on recoverability that depends on the equilibrium vapor pressure of the alloying elements and the large energy consumption. Therefore, the sustainable recycling of EoL magnesium products should be an important consideration in the design of advanced magnesium alloys or the development of new refining processes.

  13. Magnesium battery disposal characteristics

    NASA Astrophysics Data System (ADS)

    Soffer, Louis; Atwater, Terrill

    1994-12-01

    This study assesses the disposal characteristics of U.S. Army procured military magnesium batteries under current Resource Conservation and Recovery Act (RCRA) hazardous waste identification regulations administered by the U.S. Environmental Protection Agency. Magnesium batteries were tested at 100, 50, 10 and 0 percent remaining state of charge. Present findings indicate that magnesium batteries with less than 50 percent remaining charge do not exceed the federal regulatory limit of 5.0 mg/L for chromium. All other RCRA contaminates were below regulatory limits at all levels of remaining charge. Assay methods, findings, disposal requirements and design implications are discussed.

  14. Magnesium blood test

    MedlinePlus

    Magnesium - blood ... A blood sample is needed. ... When the needle is inserted to draw blood, some people feel slight pain. Others feel a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon ...

  15. Interstellar magnesium abundances

    NASA Technical Reports Server (NTRS)

    Murray, M. J.; Dufton, P. L.; Hibbert, A.; York, D. G.

    1984-01-01

    An improved evaluation of the Mg II 1240 A doublet oscillator strength is used in conjunction with recently published Copernicus observations to derive accurate Mg II column densities toward 74 stars. These imply an average of 40 percent of interstellar magnesium is in the gaseous phase. Magnesium depletion is examined as a function of various interstellar extinction and density parameters, and the results are briefly discussed in terms of current depletion theories.

  16. Rechargeable Magnesium Power Cells

    NASA Technical Reports Server (NTRS)

    Koch, Victor R.; Nanjundiah, Chenniah; Orsini, Michael

    1995-01-01

    Rechargeable power cells based on magnesium anodes developed as safer alternatives to high-energy-density cells like those based on lithium and sodium anodes. At cost of some reduction in energy density, magnesium-based cells safer because less susceptible to catastrophic meltdown followed by flames and venting of toxic fumes. Other advantages include ease of handling, machining, and disposal, and relatively low cost.

  17. Alkaline battery operational methodology

    DOEpatents

    Sholklapper, Tal; Gallaway, Joshua; Steingart, Daniel; Ingale, Nilesh; Nyce, Michael

    2016-08-16

    Methods of using specific operational charge and discharge parameters to extend the life of alkaline batteries are disclosed. The methods can be used with any commercial primary or secondary alkaline battery, as well as with newer alkaline battery designs, including batteries with flowing electrolyte. The methods include cycling batteries within a narrow operating voltage window, with minimum and maximum cut-off voltages that are set based on battery characteristics and environmental conditions. The narrow voltage window decreases available capacity but allows the batteries to be cycled for hundreds or thousands of times.

  18. Nephrocalcinosis and hyperlipidemia in rats fed a cholesterol- and fat-rich diet: association with hyperoxaluria, altered kidney and bone minerals, and renal tissue phospholipid-calcium interaction.

    PubMed

    Schmiedl, A; Schwille, P O; Bonucci, E; Erben, R G; Grayczyk, A; Sharma, V

    2000-12-01

    To determine whether an "atherogenic" diet (excess of cholesterol and neutral fat) induces pathological calcification in various organs, including the kidney, and abnormal oxalate metabolism, 24 male Sprague-Dawley rats were fed either normal lab chow (controls, n = 12) or the cholesterol- and fat-rich experimental diet (CH-F, n = 12) for 111 +/- 3 days. CH-F rats developed dyslipidemia [high blood levels of triglycerides, total, low-density lipoprotein (LDL)-, very low-density lipoprotein (VLDL)-, high-density lipoprotein (HDL)-bound cholesterol, total phospholipids], elevated serum total alkaline phosphatase and lactate dehydrogenase (LDH) levels, in the absence of changes in overall renal function, extracellular mineral homeostasis [serum protein-corrected total calcium, magnesium, parathyroid hormone (PTH), 1,25-dihydroxyvitamin D (1,25(OH)2D)], plasma glycolate and oxalate levels. There was a redistribution of bone calcium and enhanced exchange of this within the extraosseous space, which was accompanied by significant bone calcium loss, but normal bone histomorphometry. Liver oxalate levels, if expressed per unit of defatted (DF) dry liver, were three times higher than in the controls. Urinary glycolate, oxalate, calcium and total protein excretion levels were elevated, the latter showing an excess of proteins > 100 kD and a deficit of proteins > 30-50 kD. Urinary calcium oxalate supersaturation was increased, and calcium phosphate supersaturation was unchanged. There were dramatically increased (by number, circumference, and area) renal calcium phosphate calcifications in the cortico-medullary region, but calcium oxalate deposits were not detectable. Electron microscopy (EM) and elemental analysis revealed intratubular calcium phosphate, apparently needle-like hydroxyapatite. Immunohistochemistry of renal tissue calcifications revealed co-localization of phospholipids and calcium phosphate. It is concluded that rats fed the CH-F diet exhibited: (1) a

  19. Magnesium for Future Autos

    SciTech Connect

    Nyberg, Eric A.; Luo, Alan A.; Sadayappan, Kumar; Shi, Wenfang

    2008-10-01

    In the quest for better fuel economy and improved environmental performance, magnesium may well become a metal of choice for constructing lighter, more efficient vehicles. Magnesium is the lightest structural metal, yet it has a high strength-to-weight ratio makes it comparable to steel in many applications. The world’s automakers already use magnesium for individual components. But new alloys and processing methods are needed before the metal can become economically and technologically feasible as a major automotive structural material. This article will explore the formation, challenges and initial results of an international collaboration—the Magnesium Front End Research and Development (MFERD) project—that is leveraging the expertise and resources of Canada, China and the United States to advance the creation of magnesium-intensive vehicles. The MFERD project aims to develop the enabling technologies and knowledge base that will lead to a vehicles that are 50-60 percent lighter, equally affordable, more recyclable and of equal or better quality when compared to today’s vehicles. Databases of information also will be captured in models to enable further alloy and manufacturing process optimization. Finally, a life-cycle analysis of the magnesium used will be conducted.

  20. Electrodeposition of magnesium and magnesium/aluminum alloys

    DOEpatents

    Mayer, Anton

    1988-01-01

    Electrolytes and plating solutions for use in processes for electroplating and electroforming pure magnesium and alloys of aluminum and magnesium and also electrodeposition processes. An electrolyte of this invention is comprised of an alkali metal fluoride or a quaternary ammonium halide, dimethyl magnesium and/or diethyl magnesium, and triethyl aluminum and/or triisobutyl aluminum. An electrolyte may be dissolved in an aromatic hydrocarbon solvent to form a plating solution. The proportions of the component compounds in the electrolyte are varied to produce essentially pure magnesium or magnesium/aluminum alloys having varying selected compositions.

  1. Electrodeposition of magnesium and magnesium/aluminum alloys

    DOEpatents

    Mayer, A.

    1988-01-21

    Electrolytes and plating solutions for use in processes for electroplating and electroforming pure magnesium and alloys of aluminum and magnesium and also electrodeposition processes. An electrolyte of this invention is comprised of an alkali metal fluoride or a quaternary ammonium halide, dimethyl magnesium and/or diethyl magnesium, and triethyl aluminum and/or triisobutyl aluminum. An electrolyte may be dissolved in an aromatic hydrocarbon solvent to form a plating solution. The proportions of the component compounds in the electrolyte are varied to produce essentially pure magnesium or magnesium/aluminum alloys having varying selected compositions.

  2. Influences of alkaline ionized water on milk electrolyte concentrations in maternal rats.

    PubMed

    Watanabe, T; Kamata, H; Fukuda, Y; Murasugi, E; Sato, T; Uwatoko, K; Pan, I J

    2000-12-01

    We previously reported that body weight on day 14 after birth in male offspring of rats given alkaline ionized water (AKW) was significantly heavier than that in offspring of rats given tap water (TPW), but no significant difference was noted in milk yield and in suckled milk volume between the two groups. Additionally, the offspring in the AKW group and TPW group were given AKW and TPW, respectively, at weaning, and unexpectedly, the necrotic foci in the cardiac muscle were observed at the 15-week-old age in the AKW group, but not in the TPW group. The present study was designed to clarify the factors which are involved in that unusual increase of body weight and occurrence of cardiac necrosis. Eight dams in each group were given AKW or TPW (control) from day 0 of gestation to day 14 of lactation. The milk samples were collected on day 14 of lactation and analyzed for concentrations of calcium (Ca), sodium (Na), potassium (K), magnesium (Mg) and chloride (Cl). The AKW and TPW were also analyzed. Ca, Na and K levels in milk were significantly higher in the AKW group compared to the TPW group. No significant difference was noted in the Mg and Cl levels between the two groups. These data suggested that the Ca cation of AKW enriched the Ca concentration of the milk and accelerated the postnatal growth of the offspring of rats given AKW.

  3. The Characterization of Eu2+-Doped Mixed Alkaline-Earth Iodide Scintillator Crystals

    SciTech Connect

    Neal, John S; Boatner, Lynn A; Ramey, Joanne Oxendine; Wisniewski, D.; Kolopus, James A; Cherepy, Nerine; Payne, Stephen A.

    2011-01-01

    The high-performance inorganic scintillator, SrI2:Eu2+, when activated with divalent europium in the concentration range of 3 to 6%, has shown great promise for use in applications that require high-energy-resolution gamma-ray detection. We have recently grown and tested crystals in which other alkaline-earth ions have been partially substituted for Sr ions. Specifically, europium-doped single crystals have been grown in which up to 30 at % of the strontium ions have been substituted for either by barium, magnesium, or calcium ions. In the case of the strontium iodide scintillator host, a material that is characterized by an orthorhombic crystal structure, there are three other column IIA elements that are obvious choices for investigations whose purpose is to realize potential improvements in the performance of SrI2:Eu2+-based scintillators via the replacement of strontium ions with either Mg2+, Ca2+, or Ba2+. Light yields of up to 81,400 photons/MeV with an associated energy resolution of 3.7% (fwhm for 662 keV gamma-rays) have been observed in the case of a partial substitution of Ba2+ for Sr2+. The measured decay times ranged from 1.1 to 2.0 s, while the peak emission wavelengths ranged from 432 to 438 nm.

  4. Tris(pyrazolyl)methanides of the alkaline earth metals: influence of the substitution pattern on stability and degradation.

    PubMed

    Müller, Christoph; Koch, Alexander; Görls, Helmar; Krieck, Sven; Westerhausen, Matthias

    2015-01-20

    Trispyrazolylmethanides commonly act as strong tridentate bases toward metal ions. This expected coordination behavior has been observed for tris(3,4,5-trimethylpyrazolyl)methane (1a), which yields the alkaline-earth-metal bis[tris(3,4,5-trimethylpyrazolyl)methanides] of magnesium (1b), calcium (1c), strontium (1d), and barium (1e) via deprotonation of 1a with dibutylmagnesium and [Ae{N(SiMe3)2}2] (Ae = Mg, Ca, Sr, and Ba, respectively). Barium complex 1e degrades during recrystallization that was attempted from aromatic hydrocarbons and ethers. In these scorpionate complexes, the metal ions are embedded in distorted octahedral coordination spheres. Contrarily, tris(3-thienylpyrazolyl)methane (2a) exhibits a strikingly different reactivity. Dibutylmagnesium is unable to deprotonate 2a, whereas [Ae{N(SiMe3)2}2] (Ae = Ca, Sr, and Ba) smoothly metalates 2a. However, the primary alkaline-earth-metal bis[tris(3-thienylpyrazolyl)methanides] of Ca (2c), Sr (2d), and Ba (2e) represent intermediates and degrade under the formation of the alkaline-earth-metal bis(3-thienylpyrazolates) of calcium (3c), strontium (3d), and barium (3e) and the elimination of tetrakis(3-thienylpyrazolyl)ethene (4). To isolate crystalline compounds, 3-thienylpyrazole has been metalated, and the corresponding derivatives [(HPz(Tp))4Mg(Pz(Tp))2] (3b), dinuclear [(tmeda)Ca(Pz(Tp))2]2 (3c), mononuclear [(pmdeta)Sr(Pz(Tp))2] (3d), and [(hmteta)Ba(Pz(Tp))2] (3e) have been structurally characterized. Regardless of the applied stoichiometry, magnesiation of thienylpyrazole 3a with dibutylmagnesium yields [(HPz(Tp))4Mg(Pz(Tp))2] (3b), which is stabilized in the solid state by intramolecular N-H···N···H-N hydrogen bridges. The degradation of [Ae{C(Pz(R))3}2] (R = Ph and Tp) has been studied by quantum chemical methods, the results of which propose an intermediate complex of the nature [{(Pz(R))2C}2Ca{Pz(R)}2]; thereafter, the singlet carbenes ([:C(Pz(R))2]) dimerize in the vicinity of the alkaline

  5. Magnesium-containing mixed coatings on zirconia for dental implants: mechanical characterization and in vitro behavior.

    PubMed

    Pardun, Karoline; Treccani, Laura; Volkmann, Eike; Streckbein, Philipp; Heiss, Christian; Gerlach, Juergen W; Maendl, Stephan; Rezwan, Kurosch

    2015-07-01

    An important challenge in the field of dental and orthopedic implantology is the preparation of implant coatings with bioactive functions that feature a high mechanical stability and at the same time mimic structural and compositional properties of native bone for a better bone ingrowth. This study investigates the influence of magnesium addition to zirconia-calcium phosphate coatings. The mixed coatings were prepared with varying additions of either magnesium oxide or magnesium fluoride to yttria-stabilized zirconia and hydroxyapatite. The coatings were deposited on zirconia discs and screw implants by wet powder spraying. Microstructure studies confirm a porous coating with similar roughness and firm adhesion not hampered by the coating composition. The coating morphology, mechanical flexural strength and calcium dissolution showed a magnesium content-dependent effect. Moreover, the in vitro results obtained with human osteoblasts reveal an improved biological performance caused by the presence of Mg(2+) ions. The magnesium-containing coatings exhibited better cell proliferation and differentiation in comparison to pure zirconia-calcium phosphate coatings. In conclusion, these results demonstrate that magnesium addition increases the bioactivity potential of zirconia-calcium phosphate coatings and is thus a highly suitable candidate for bone implant coatings.

  6. Dolomite magnesium oxychloride cement properties control method during its production

    NASA Astrophysics Data System (ADS)

    Chernykh, T. N.; Nosov, A. V.; Kramar, L. Ya

    2015-01-01

    The work considers the possibility of reducing the decomposition temperature of MgCO3 in dolomite rock, provides the results of studies of the effect of various additives and enhancers on the decomposition of magnesium and calcium components of dolomite. Chlorides additives are the most promising for dolomite rocks roast intensification. They allow shifting the MgCO3 decomposition to lower temperatures, without exerting a significant influence on the decomposition of CaCO3. Introduction of additives-enhancers is found to be an effective method of controlling the properties of dolomite MOC during roasting, producing high-strength dolomite magnesium oxychloride cements with change in volume during solidification.

  7. 21 CFR 184.1434 - Magnesium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Magnesium phosphate. 184.1434 Section 184.1434... Listing of Specific Substances Affirmed as GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes both magnesium phosphate, dibasic, and magnesium phosphate, tribasic. Magnesium phosphate,...

  8. 21 CFR 184.1434 - Magnesium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Magnesium phosphate. 184.1434 Section 184.1434... Listing of Specific Substances Affirmed as GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes both magnesium phosphate, dibasic, and magnesium phosphate, tribasic. Magnesium phosphate,...

  9. 21 CFR 184.1434 - Magnesium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Magnesium phosphate. 184.1434 Section 184.1434... GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes both magnesium phosphate, dibasic, and magnesium phosphate, tribasic. Magnesium phosphate, dibasic (MgHPO4·3H2O, CAS Reg. No....

  10. Calcium Modulation of Plant Plasma Membrane-Bound Atpase Activities

    NASA Technical Reports Server (NTRS)

    Caldwell, C.

    1983-01-01

    The kinetic properties of barley enzyme are discussed and compared with those of other plants. Possibilities for calcium transport in the plasma membrane by proton pump and ATPase-dependent calcium pumps are explored. Topics covered include the ph phase of the enzyme; high affinity of barley for calcium; temperature dependence, activation enthalpy, and the types of ATPase catalytic sites. Attention is given to lipids which are both screened and bound by calcium. Studies show that barley has a calmodulin activated ATPase that is found in the presence of magnesium and calcium.

  11. The MCVD synthesis and characterization of water tolerant fiber optic waveguides based on alkaline earth-doped silicas

    NASA Astrophysics Data System (ADS)

    Farley, Kevin F.

    Optical fibers that transmit throughout the entire telecommunications spectrum (1.2--1.7 mum) are presently manufactured by the removal of hydrogen or OH from the host preform glass. Hydrogen-oxygen torches are utilized in the conventional preform manufacturing process, but result in the formation of hydroxyls in germanium-doped silica fiber. The hydroxyl species generate unacceptably high losses for long haul telecommunications systems. This thesis has explored an alternative strategy for reducing OH-related absorption in silica-based glasses. Alkaline earth modifiers have been introduced via the modified chemical vapor deposition (MCVD) process to successfully damp out and dramatically reduce the extrinsic attenuation associated with both water and hydrogen. Specifically, alkaline earth ions were introduced into alumino-silicate glasses to form MgO-Al2O3-SiO2, CaO-Al 2O3-SiO2, and SrO-Al2O3-SiO 2 compositions. The utilization of halide precursors based on the vapor delivery of rare earths was incorporated into the existing MCVD set-up to fabricate these optical preforms. Both the bulk preforms and fibers drawn from them were characterized to determine relevant optical properties, including the attenuation, index profiles and extinction coefficients arising from OH in each host. The data indicate that modification of the silica glass structure through the additions of modifying ions can significantly reduce OH related absorption. For example, the doping of alkaline earth ions decreased the extinction coefficient measured at the 1.39 mum) OH overtone, to values < 0.2 L/(mol*cm). Prompt gamma activation analysis (PGAA) measurements conducted at the National Institute of Standards and Technology (NIST) found OH concentrations in the glasses in the range from 10 to 27.5 ppm. The alkaline earth-doped fibers exhibited lower OH absorption at 1.39 mum) than germanium and aluminum-doped reference fibers. Fibers doped with either magnesium, calcium or strontium displayed up

  12. Corrosion in Magnesium and a Magnesium Alloy

    NASA Astrophysics Data System (ADS)

    Akavipat, Sanay

    Magnesium and a magnesium alloy (AZ91C) have been ion implanted over a range of ions energies (50 to 150 keV) and doses (1 x 10('16) to 2 x 10('17) ions/cm('2)) to modify the corrosion properties of the metals. The corrosion tests were done by anodic polarization in chloride -free and chloride-containing aqueous solutions of a borated -boric acid with a pH of 9.3. Anodic polarization measurements showed that some implantations could greatly reduce the corrosion current densities at all impressed voltages and also increased slightly the pitting potential, which indicated the onset of the chloride attack. These improvements in corrosion resistance were caused by boron implantations into both types of samples. However, iron implantations were found to improve only the magnesium alloy. To study the corrosion in more detail, Scanning Auger Microprobe Spectrometer (SAM), Scanning Electron Microscope (SEM) with an X-ray Energy Spectrometry (XES) attachment, and Transmission Electron Microscope (TEM) measurements were used to analyze samples before, after, and at various corrosion stages. In both the unimplanted pure magnesium and AZ91C samples, anodic polarization results revealed that there were three active corrosion stages (Stages A, C, and E) and two passivating stages (Stages B and D). Examination of Stages A and B in both types of samples showed that only a mild, generalized corrosion had occurred. In Stage C of the TD samples, a pitting breakdown in the initial oxide film was observed. In Stage C of the AZ91C samples, galvanic and intergranular attack around the Mg(,17)Al(,12) intermetallic islands and along the matrix grain boundaries was observed. Stage D of both samples showed the formation of a thick, passivating oxygen containing, probably Mg(OH)(,2) film. In Stage E, this film was broken down by pits, which formed due to the presence of the chloride ions in both types of samples. Stages A through D of the unimplanted samples were not seen in the boron or iron

  13. Magnesium Metabolism and its Disorders

    PubMed Central

    Swaminathan, R

    2003-01-01

    Magnesium is the fourth most abundant cation in the body and plays an important physiological role in many of its functions. Magnesium balance is maintained by renal regulation of magnesium reabsorption. The exact mechanism of the renal regulation is not fully understood. Magnesium deficiency is a common problem in hospital patients, with a prevalence of about 10%. There are no readily available and easy methods to assess magnesium status. Serum magnesium and the magnesium tolerance test are the most widely used. Measurement of ionised magnesium may become more widely available with the availability of ion selective electrodes. Magnesium deficiency and hypomagnesaemia can result from a variety of causes including gastrointestinal and renal losses. Magnesium deficiency can cause a wide variety of features including hypocalcaemia, hypokalaemia and cardiac and neurological manifestations. Chronic low magnesium state has been associated with a number of chronic diseases including diabetes, hypertension, coronary heart disease, and osteoporosis. The use of magnesium as a therapeutic agent in asthma, myocardial infarction, and pre-eclampsia is also discussed. Hypermagnesaemia is less frequent than hypomagnesaemia and results from failure of excretion or increased intake. Hypermagnesaemia can lead to hypotension and other cardiovascular effects as well as neuromuscular manifestations. Causes and management of hypermagnesaemia are discussed. PMID:18568054

  14. Calcium - urine

    MedlinePlus

    ... into the urine, which causes calcium kidney stones Sarcoidosis Taking too much calcium Too much production of ... Milk-alkali syndrome Proximal renal tubular acidosis Rickets Sarcoidosis Vitamin D Review Date 5/3/2015 Updated ...

  15. Lack of marked cyto- and genotoxicity of cristobalite in devitrified (heated) alkaline earth silicate wools in short-term assays with cultured primary rat alveolar macrophages.

    PubMed

    Ziemann, Christina; Harrison, Paul T C; Bellmann, Bernd; Brown, Robert C; Zoitos, Bruce K; Class, Philippe

    2014-02-01

    Alkaline earth silicate (AES) wools are low-biopersistence high-temperature insulation wools. Following prolonged periods at high temperatures they may devitrify, producing crystalline silica (CS) polymorphs, including cristobalite, classified as carcinogenic to humans. Here we investigated the cytotoxic and genotoxic significance of cristobalite present in heated AES wools. Primary rat alveolar macrophages were incubated in vitro for 2 h with 200 µg/cm² unheated/heated calcium magnesium silicate wools (CMS1, CMS2, CMS3; heat-treated for 1 week at, or 4 weeks 150 °C below, their respective classification temperatures) or magnesium silicate wool (MS; heated for 24 h at 1260 °C). Types and quantities of CS formed, and fiber size distribution and shape were determined by X-ray diffraction and electron microscopy. Lactate dehydrogenase release and alkaline and hOGG1-modified comet assays were used, ± aluminum lactate (known to quench CS effects), for cytotoxicity/genotoxicity screening. Cristobalite content of wools increased with heating temperature and duration, paralleled by decreases in fiber length and changes in fiber shape. No marked cytotoxicity, and nearly no (CMS) or only slight (MS) DNA-strand break induction was observed, compared to the CS-negative control Al₂O₃, whereas DQ12 as CS-positive control was highly active. Some samples induced slight oxidative DNA damage, but no biological endpoint significantly correlated with free CS, quartz, or cristobalite. In conclusion, heating of AES wools mediates changes in CS content and fiber length/shape. While changes in fiber morphology can impact biological activity, cristobalite content appears minor or of no relevance to the intrinsic toxicity of heated AES wools in short-term assays with rat alveolar macrophages.

  16. Calcium and nitrogen balance, experiment M007

    NASA Technical Reports Server (NTRS)

    Whedon, G. D.; Lutwak, L.; Neuman, W. F.; Lachance, P. A.

    1971-01-01

    The collection of data on the response of the skeletal and muscular systems to 14-day space flights was evaluated for loss of calcium, nitrogen, and other metabolically related elements. Considerable interindividual variability was demonstrated in all experimental factors that were measured. Calcium balance became less positive and urinary phosphate excretion increased substantially in flight despite a reduction in phosphate intake. Patterns of excretion of magnesium, sodium, potassium, and chloride were different for each subject, and, in part, could be correlated with changes in adrenocortical steroid production. The principal hormonal change was a striking decrease during flight in the urinary excretion of 17-hydroxycortocosteroids. Dermal losses of calcium, magnesium, sulfate, and phosphate were insignificant during all three phases.

  17. Identifying the presence of a disulfide linkage in peptides by the selective elimination of hydrogen disulfide from collisionally activated alkali and alkaline earth metal complexes.

    PubMed

    Kim, Hugh I; Beauchamp, J L

    2008-01-30

    We report a new method for identifying disulfide linkages in peptides using mass spectrometry. This is accomplished by collisional activation of singly charged cationic alkali and alkaline earth metal complexes, which results in the highly selective elimination of hydrogen disulfide (H2S2). Complexes of peptides possessing disulfide bonds with sodium and alkaline earth metal are generated using electrospray ionization (ESI). Isolation followed by collision induced dissociation (CID) of singly charged peptide complexes results in selective elimination of H2S2 to leave newly formed dehydroalanine residues in the peptide. Further activation of the product yields sequence information in the region previously short circuited by the disulfide bond. For example, singly charged magnesium and calcium ion bound complexes of [Lys8]-vasopressin exhibit selective elimination of H2S2 via low-energy CID. Further isolation of the product followed by CID yields major b- and z-type fragments revealing the peptide sequence in the region between the newly formed dehydroalanine residues. Numerous model peptides provide mechanistic details for the selective elimination of H2S2. The process is initiated starting with a metal stabilized enolate anion at Cys, followed by cleavage of the S-C bond. An examination of the peptic digest of insulin provides an example of the application of the selective elimination of H2S2 for the identification of peptides with disulfide linkages. The energetics and mechanisms of H2S2 elimination from model compounds are investigated using density functional theory (DFT) calculations.

  18. Batch and column adsorption of herbicide fluroxypyr on different types of activated carbons from water with varied degrees of hardness and alkalinity.

    PubMed

    Pastrana-Martínez, L M; López-Ramón, M V; Fontecha-Cámara, M A; Moreno-Castilla, C

    2010-02-01

    There has been little research into the effects of the water hardness and alkalinity of surface waters on the adsorption of herbicides on activated carbons. The aim of this study was to determine the influence of these water characteristics on fluroxypyr adsorption on different activated carbons. At low fluroxypyr surface concentrations, the amount adsorbed from distilled water was related to the surface hydrophobicity. Surface area of carbons covered by fluroxypyr molecules ranged from 60 to 65%. Variations in fluroxypyr solubility with water hardness and alkalinity showed a salting-in effect. Calcium, magnesium and bicarbonate ions were adsorbed to a varied extent on the activated carbons. The presence of fluroxypyr in solution decreased their adsorption due to a competition effect. K(F) from the Freundlich equation linearly increased with water hardness due to salt-screened electrostatic repulsions between charged fluroxypyr molecules. The amount adsorbed from distilled water was largest at high fluroxypyr solution concentrations, because there was no competition between inorganic ions and fluroxypyr molecules. The column breakthrough volume and the amount adsorbed at breakthrough were smaller in tap versus distilled water. Carbon consumption was lower with activated carbon cloth than with the use of granular activated carbon.

  19. Magnesium-enhanced enzymatically mineralized platelet-rich fibrin for bone regeneration applications.

    PubMed

    Gassling, Volker; Douglas, Timothy E L; Purcz, Nicolai; Schaubroeck, David; Balcaen, Lieve; Bliznuk, Vitaliy; Declercq, Heidi A; Vanhaecke, Frank; Dubruel, Peter

    2013-10-01

    Membranes of the autologous blood-derived biomaterial platelet-rich fibrin (PRF) were mineralized enzymatically with calcium phosphate (CaP) by the incorporation of alkaline phosphatase (ALP) followed by incubation for 3 days in solutions of either 0.1 M calcium glycerophosphate (CaGP) or a combination of CaGP and magnesium glycerophosphate (CaGP:MgGP; both 0.05 M), resulting in the formation of two different PRF-mineral composites. Fourier transform infrared spectroscopy, transmission electron microscopy and selected area electron diffraction examinations showed that the CaP formed was amorphous. Inductively coupled plasma optical emission spectroscopy analysis revealed similar amounts of Ca and P in both composite types, while a smaller amount of Mg (Ca:Mg molar ratio = 10) was detected in the composites formed in the CaGP:MgGP solution, which was supported by the results of energy-dispersive x-ray spectroscopy-based elemental mapping. Scanning electron microscopy (SEM) imaging showed that the mineral deposits in PRF incubated in the CaGP:MgGP solution were markedly smaller. The mass percentage attributable to the mineral phase was similar in both composite types. MTT and WST tests with SAOS-2 cells revealed that incubation in the CaGP:MgGP solution had no negative effect on cytocompatibility and cell proliferation compared to the CaGP solution. Cells on all samples displayed a well-spread morphology as revealed by SEM imaging. In conclusion, the incorporation of Mg reduces mineral deposit dimensions and promotes cell proliferation.

  20. Complexometric determination of magnesium in nodular cast iron and alloyed cast iron roll samples.

    PubMed

    Banerjee, S; Dutta, R K

    1980-02-01

    A complexometric method for the determination of magnesium in nodular cast iron, alloyed cast iron and roll samples has been developed. The bulk of the iron is removed by ether extraction and the phosphate as zirconium phosphate. The other elements are removed by extraction with dithiocarbamate into chloroform. Magnesium is then titrated with EDTA at pH 10, with Eriochrome Black T as indicator. Calcium interferes, but is very rarely present in such cast iron samples.

  1. MAGNESIUM MONO POTASSIUM PHOSPHATE GROUT FOR P-REACTOR VESSEL IN-SITU DECOMISSIONING

    SciTech Connect

    Langton, C.; Stefanko, D.

    2011-01-05

    The objective of this report is to document laboratory testing of magnesium mono potassium phosphate grouts for P-Reactor vessel in-situ decommissioning. Magnesium mono potassium phosphate 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 (pH of about 12.4). A less alkaline material ({<=} 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. Information concerning access points into the P-Reactor vessel and amount of aluminum metal in the vessel is provided elsewhere. Fresh and cured properties were measured for: (1) commercially blended magnesium mono potassium phosphate packaged grouts, (2) commercially available binders blended with inert fillers at SRNL, (3) grouts prepared from technical grade MgO and KH{sub 2}PO{sub 4} and inert fillers (quartz sands, Class F fly ash), and (4) Ceramicrete{reg_sign} magnesium mono potassium phosphate-based grouts prepared at Argonne National Laboratory. Boric acid was evaluated as a set retarder in the magnesium mono potassium phosphate mixes.

  2. Magnesium fortification of drinking water suppresses atherogenesis in male LDL-receptor-deficient mice.

    PubMed

    Sherer, Y; Shaish, A; Levkovitz, H; Keren, P; Janackovic, Z; Shoenfeld, Y; Harats, D

    1999-01-01

    Magnesium, an important cofactor of more than 300 enzymes, has previously been found to modulate blood lipid levels, atherogenesis and atherosclerosis in rabbits, when added to their diet. The aim of this study was to examine whether magnesium fortification of drinking water, without a change in diet content, can affect atherogenesis. The study included six groups of LDL-receptor-deficient mice. The mice received either distilled water or water containing 50 g of magnesium sulfate per liter. In the first (12 weeks) and second (6 weeks) stages of the experiment, the mice received low- and high-cholesterol diets, respectively. At the end of each stage, blood was drawn for the determination of plasma magnesium, calcium and lipid levels. In addition, the extent of atherosclerosis was determined at the aortic sinus. In both males and females, magnesium fortification was associated with higher levels of plasma magnesium (50 and 37% increase, respectively), without any differences in plasma calcium content. The extent of atherosclerosis at the aortic sinus in the male mice that received high levels of magnesium was a third of that of the male mice that received distilled water. However, these differences were not found in the female groups. Surprisingly, the female mice that received water fortified with magnesium had higher levels of cholesterol after stage 2, whereas no differences regarding plasma lipid levels were found among the male mice. These results confirm that magnesium fortification of drinking water is capable of inhibiting atherogenesis in male LDL-receptor-deficient mice. The mechanisms of action are yet to be discovered, and are probably not related to diminished lipid excretion, but possibly to the prevention of calcium influx into vascular smooth muscle cells, elevated antioxidative capacity, or other yet undetermined mechanisms.

  3. Magnesium Research and Technology Development

    SciTech Connect

    Nyberg, Eric A.; Joost, William; Smith, Mark T.

    2009-12-30

    The Magnesium Research and Technical Development (MR&TD) project supports efforts to increase using magnesium in automotive applications, including improving technology, lowering costs and increasing the knowledge needed to enable alloy and manufacturing process optimization. MR&TD supports the U.S. Department of Energy (DOE)/United States Automotive Materials Partnership (USAMP) Magnesium Front End Research and Development (MFERD) project in collaboration with China and Canada. The MR&TD projects also maintains the magnesium bibliographic database at magnesium.pnl.gov.

  4. The Importance of Magnesium in the Human Body: A Systematic Literature Review.

    PubMed

    Glasdam, Sidsel-Marie; Glasdam, Stinne; Peters, Günther H

    2016-01-01

    Magnesium, the second and fourth most abundant cation in the intracellular compartment and whole body, respectively, is of great physiologic importance. Magnesium exists as bound and free ionized forms depending on temperature, pH, ionic strength, and competing ions. Free magnesium participates in many biochemical processes and is most commonly measured by ion-selective electrode. This analytical approach is problematic because complete selectivity is not possible due to competition with other ions, i.e., calcium, and pH interference. Unfortunately, many studies have focused on measurement of total magnesium rather than its free bioactive form making it difficult to correlate to disease states. This systematic literature review presents current analytical challenges in obtaining accurate and reproducible test results for magnesium.

  5. Alkaline flooding injection strategy

    SciTech Connect

    French, T.R.; Josephson, C.B.

    1992-03-01

    The objective of this project is to improved alkali-surfactant flooding methods, and this includes determining the proper design of injection strategy. Several different injection strategies have been used or suggested for recovering heavy oils with surfactant-enhanced alkaline flooding methods. Oil recovery was compared for four different injection strategies: (1) surfactant followed by polymer, (2) surfactant followed by alkaline polymer, (3) alkaline surfactant followed by polymer, and (4) alkali, surfactant, and polymer mixed in a single formulation. The effect of alkaline preflush was also studied under two different conditions. All of the oil recovery experiments were conducted under optimal conditions with a viscous, non-acidic oil from Hepler (KS) oil field. The coreflood experiments were conducted with Berea sandstone cores since field core was not available in sufficient quantity for coreflood tests. The Tucker sand of Hepler field is a Class I fluvial dominated deltaic reservoir, as classified by the Department of Energy, which has been selected as the site of a DOE-sponsored field pilot test.

  6. Defoaming effect of calcium soap.

    PubMed

    Zhang, Hui; Miller, Clarence A; Garrett, Peter R; Raney, Kirk H

    2004-11-15

    The effect of calcium oleate on foam stability was studied for aqueous solutions of two commonly used surfactants (anionic and nonionic) under alkaline conditions in the absence of oil. For the anionic surfactant, defoaming by calcium oleate appears to involve two mechanisms. One is that oleate and calcium ions are presumably incorporated into the surfactant monolayers with a resulting decrease in the maximum of the disjoining pressure curve and therefore produces less stable thin films. The other is bridging of the films by calcium oleate particles. The latter mechanism was especially important in freshly made solutions where precipitation in the aqueous phase was still occurring when the foam was generated. Foams generated after aging (hours) when precipitation was nearly complete were more stable even though solution turbidities were greater. Foams of the nonionic surfactant were less stable than those of the anionic surfactant but were also destabilized by sufficient amounts of calcium oleate and exhibited a similar aging effect. A simplified model was developed for estimating the sodium oleate concentration at which precipitation commences in solutions of the anionic surfactant containing dissolved calcium. It includes enhancement of calcium content in the electrical double layers of the surfactant micelles. Predictions of the model were in agreement with experiment.

  7. Low levels of serum ionized magnesium are found in patients early after stroke which result in rapid elevation in cytosolic free calcium and spasm in cerebral vascular muscle cells.

    PubMed

    Altura, B T; Memon, Z I; Zhang, A; Cheng, T P; Silverman, R; Cracco, R Q; Altura, B M

    1997-07-11

    Ninety-eight patients admitted to the emergency rooms of three urban hospitals with a diagnosis of either ischemic stroke or hemorrhagic stroke exhibited early and significant deficits in serum ionized Mg2+ (IMg2+), but not total Mg, as measured with a unique Mg2+-sensitive ion-selective electrode. Twenty-five percent of these stroke patients exhibited >65% reductions in the mean serum IMg2+ found in normal healthy human volunteers or patients admitted for minor bruises, cuts or deep lacerations. The stroke patients also demonstrated significant elevation in the serum ionized Ca2+ (ICa2+)/IMg2+ ratio, a sign of increased vascular tone and cerebrovasospasm. Exposure of primary cultured canine cerebral vascular smooth muscle cells to the low concentrations of IMg2+ found in the stroke patients, e.g. 0.30-0.48 mM, resulted in rapid and marked elevations in cytosolic free calcium ions ([Ca2+]i) as measured with the fluorescent probe, fura-2, and digital image analysis. Coincident with the rise in [Ca2+]i, many of the cerebral vascular cells went into spasm. Reintroduction of normal extracellular Mg2+ ion concentrations failed to either lower the [Ca2+]i overload or reverse the rounding-up of the cerebral vascular cells. These results suggest that changes in Mg2+ metabolism play important roles in stroke syndromes and in the etiology of cerebrovasospasm associated with cerebral hemorrhage.

  8. Nondestructive spot test method for magnesium and magnesium alloys

    NASA Technical Reports Server (NTRS)

    Wilson, M. L. (Inventor)

    1973-01-01

    A method for spot test identification of magnesium and various magnesium alloys commonly used in aerospace applications is described. The spot test identification involves color codes obtained when several drops of 3 M hydrochloric acid are placed on the surface to be tested. After approximately thirty seconds, two drops of this reacted acid is transferred to each of two depressions in a spot plate for additions of other chemicals with subsequent color changes indicating magnesium or its alloy.

  9. Highly Soluble Alkoxide Magnesium Salts for Rechargeable Magnesium Batteries

    SciTech Connect

    Liao, Chen; Guo, Bingkun; Jiang, Deen; Custelcean, Radu; Mahurin, Shannon Mark; Sun, Xiao-Guang; Dai, Sheng

    2014-01-01

    A unique class of air-stable and non-pyrophoric magnesium electrolytes has been developed based on alkoxide magnesium compounds. The crystals obtained from this class of electrolytes exhibit a unique structure of tri-magnesium cluster, [Mg3Cl3(OR)2(THF)6]+ [(THF)MgCl3] . High reversible capacities and good rate capabilities were obtained in Mg-Mo6S8 batteries using these new electrolytes at both 20 and 50 oC.

  10. Positron elastic scattering from alkaline earth targets

    NASA Astrophysics Data System (ADS)

    Poveda, Luis A.; Assafrão, Denise; Mohallem, José R.

    2016-07-01

    A previously reported model potential approach [Poveda et al., Phys. Rev. A 87, 052702 (2013)] was extended to study low energy positron elastic scattering from beryllium and magnesium. The cross sections were computed for energies ranging from 10-5 eV up to well above the positronium formation threshold. The present results are in good agreement with previous reports, including the prediction of a p-wave resonance in the cross section for magnesium. The emergence of this shape resonance is connected to a trend observed in the evolution of the partial wave cross section in going from Be to Mg target. This trend lead us to speculate that a sharp d-wave resonance should be observed in positron elastic scattering from calcium. The positron-target binding energies are investigated in detail, both using the scattering information and by direct computation of the bound state energies using the model potentials. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.Supplementary material in the form of one pdf file available from the Journal web page at http://dx.doi.org/10.1140/epjd/e2016-70120-y

  11. Constraining magnesium cycling in marine sediments using magnesium isotopes

    NASA Astrophysics Data System (ADS)

    Higgins, J. A.; Schrag, D. P.

    2010-09-01

    Magnesium concentrations in deep-sea sediment pore-fluids typically decrease down core due to net precipitation of dolomite or clay minerals in the sediments or underlying crust. To better characterize and differentiate these processes, we have measured magnesium isotopes in pore-fluids and sediment samples from Ocean Drilling Program sites (1082, 1086, 1012, 984, 1219, and 925) that span a range of oceanographic settings. At all sites, magnesium concentrations decrease with depth. At sites where diagenetic reactions are dominated by the respiration of organic carbon, pore-fluid δ 26Mg values increase with depth by as much as 2‰. Because carbonates preferentially incorporate 24Mg (low δ 26Mg), the increase in pore-fluid δ 26Mg values at these sites is consistent with the removal of magnesium in Mg-carbonate (dolomite). In contrast, at sites where the respiration of organic carbon is not important and/or weatherable minerals are abundant, pore-fluid δ 26Mg values decrease with depth by up to 2‰. The decline in pore-fluid δ 26Mg at these sites is consistent with a magnesium sink that is isotopically enriched relative to the pore-fluid. The identity of this enriched magnesium sink is likely clay minerals. Using a simple 1D diffusion-advection-reaction model of pore-fluid magnesium, we estimate rates of net magnesium uptake/removal and associated net magnesium isotope fractionation factors for sources and sinks at all sites. Independent estimates of magnesium isotope fractionation during dolomite precipitation from measured δ 26Mg values of dolomite samples from sites 1082 and 1012 are very similar to modeled net fractionation factors at these sites, suggesting that local exchange of magnesium between sediment and pore-fluid at these sites can be neglected. Our results indicate that the magnesium incorporated in dolomite is 2.0-2.7‰ depleted in δ 26Mg relative to the precipitating fluid. Assuming local exchange of magnesium is minor at the rest of the

  12. Magnesium fluoride recovery method

    DOEpatents

    Gay, Richard L.; McKenzie, Donald E.

    1989-01-01

    A method of obtaining magnesium fluoride substantially free from radioactive uranium from a slag containing the same and having a radioactivity level of at least about 7000 pCi/gm. The slag is ground to a particle size of about 200 microns or less. The ground slag is contacted with an acid under certain prescribed conditions to produce a liquid product and a particulate solid product. The particulate solid product is separated from the liquid and treated at least two more times with acid to produce a solid residue consisting essentially of magnesium fluoride substantially free of uranium and having a residual radioactivity level of less than about 1000 pCi/gm. In accordance with a particularly preferred embodiment of the invention a catalyst and an oxidizing agent are used during the acid treatment and preferably the acid is sulfuric acid having a strength of about 1.0 Normal.

  13. Alkaline quinone flow battery.

    PubMed

    Lin, Kaixiang; Chen, Qing; Gerhardt, Michael R; Tong, Liuchuan; Kim, Sang Bok; Eisenach, Louise; Valle, Alvaro W; Hardee, David; Gordon, Roy G; Aziz, Michael J; Marshak, Michael P

    2015-09-25

    Storage of photovoltaic and wind electricity in batteries could solve the mismatch problem between the intermittent supply of these renewable resources and variable demand. Flow batteries permit more economical long-duration discharge than solid-electrode batteries by using liquid electrolytes stored outside of the battery. We report an alkaline flow battery based on redox-active organic molecules that are composed entirely of Earth-abundant elements and are nontoxic, nonflammable, and safe for use in residential and commercial environments. The battery operates efficiently with high power density near room temperature. These results demonstrate the stability and performance of redox-active organic molecules in alkaline flow batteries, potentially enabling cost-effective stationary storage of renewable energy.

  14. Advanced alkaline water electrolysis

    NASA Astrophysics Data System (ADS)

    Wakabayashi, N.; Torikai, E.; Kawami, Y.; Takenaka, H.

    Results are presented of experimental studies of possible separators and electrodes for use in advanced, high-temperature, high-pressure alkaline water electrolyzers. Material evaluations in alkaline water electrolyzers at temperatures from 100 to 120 C have shown a new type polytetrafluoroethylene membrane impregnated with potassium titanate to be the most promising when the separator is prepared by the hydrothermal treatment of a porous PFTE membrane impregnated with hydrated titanium oxide. Measurements of cell voltages in 30% KOH at current densities from 5 to 100 A/sq dm at temperatures up to 120 C with nickel electrodes of various structures have shown the foamed nickel electrode, with an average pore size of 1-1.5 mm, to have the best performance. When the foamed nickel is coated by fine powdered nickel, carbonyl nickel or Raney nickel to increase electrode surface areas, even lower cell voltages were found, indicating better performance.

  15. Magnesium in Prevention and Therapy.

    PubMed

    Gröber, Uwe; Schmidt, Joachim; Kisters, Klaus

    2015-09-23

    Magnesium is the fourth most abundant mineral in the body. It has been recognized as a cofactor for more than 300 enzymatic reactions, where it is crucial for adenosine triphosphate (ATP) metabolism. Magnesium is required for DNA and RNA synthesis, reproduction, and protein synthesis. Moreover, magnesium is essential for the regulation of muscular contraction, blood pressure, insulin metabolism, cardiac excitability, vasomotor tone, nerve transmission and neuromuscular conduction. Imbalances in magnesium status-primarily hypomagnesemia as it is seen more common than hypermagnesemia-might result in unwanted neuromuscular, cardiac or nervous disorders. Based on magnesium's many functions within the human body, it plays an important role in prevention and treatment of many diseases. Low levels of magnesium have been associated with a number of chronic diseases, such as Alzheimer's disease, insulin resistance and type-2 diabetes mellitus, hypertension, cardiovascular disease (e.g., stroke), migraine headaches, and attention deficit hyperactivity disorder (ADHD).

  16. Oestrogen but not testosterone increases bone density in orchiectomized rats more when fed moderately magnesium-deficient fructose than moderately magnesium-deficient cornstarch.

    PubMed

    Koh, E T; Tae, W C; Bourdeau, J E; Chung, K W

    1994-12-01

    To investigate interactions between circulating sex hormones, dietary fructose and magnesium on bone mineral density and numbers of trabeculae, 10 weeks old orchiectomized and sham-orchiectomized rats were studied. One-third of the orchiectomized animals were injected with beta-oestradiol-3-benzoate twice per week in sesame oil; another one-third, testosterone cypionate; the remaining one-third as well as the sham-orchiectomized animals, sesame oil only. All animals were fed either fructose or cornstarch without added magnesium. After 14 weeks, a 24 h urine sample was collected for measurements of calcium, magnesium, phosphorus, and cAMP. Blood was collected for determinations of calcium, magnesium, phosphorus, 25-monohydroxy and 1,25-dihydroxycholecalciferols, oestrogen, testosterone, and parathyroid hormone. Femurs were used for measurements of bone mineral density, and tibiae, for numbers of trabeculae. Exogenous testosterone interacted with starch and magnesium deficiency to decrease serum calcium concentration significantly, which increased circulating parathyroid hormone. High circulating parathyroid hormone raised urinary cAMP and serum 1,25-dihydroxycholecalciferol. Increased parathyroid hormone, cAMP and 1,25-dihydroxycholecalciferol may be responsible for bone resorption which was noted in reductions of bone mineral density and the numbers of trabeculae in the group. In contrast, exogenous oestrogen interacted with fructose and magnesium deficiency to increase serum calcium concentration which caused a reduction of circulating parathyroid. Low parathyroid hormone, reduced 1,25-dihydroxycholecalciferol and cAMP may explain the increased bone mineral density and the numbers of trabeculae in this group.

  17. Trace mineral interactions during elevated calcium consumption

    SciTech Connect

    Smith, K.T.; Luhrsen, K.R.

    1986-03-01

    Elevated calcium consumption is reported to affect trace mineral bioavailability. The authors examined this phenomenon in both single dose radio-label test meals and an eight week feeding trial in rats. In the single dose studies, human milk, cows milk, and various calcium sources were examined in relation to radio-iron and radio-zinc retention. /sup 59/Fe retention was greater from human milk than cows milk. However, when the calcium content of human milk was adjusted (with CaHPO/sub 4/ or CaCO/sub 3/) to equal the level in cows milk, iron retention was depressed. Similarly, when calcium sources (CaCO/sub 3/, CaHPO/sub 4/, hydroxy-apatite, bone meal) were examined at different calcium:metal molar ratios, the degree of inhibition on metal retention varied. In general, phosphate salts were more inhibiting than carbonates. In the feeding trial, calcium was fed in diets at normal (0.5%) or elevated (1.5%) levels. Serum, liver, kidney, and bone trace mineral profiles were obtained. In general, most trace elements showed decreased levels in the tissues. Zinc and iron were most striking, followed by magnesium with minor changes in copper. A high calcium:high mineral supplemented group was also fed. Mixed mineral supplementation prevented all calcium interactions. These data indicate the importance of calcium mineral interactions in bioavailability considerations in both milk sources and in mineral supplementation.

  18. Magnesium Based Materials and their Antimicrobial Activity

    NASA Astrophysics Data System (ADS)

    Robinson, Duane Allan

    The overall goals of this body of work were to characterize the antimicrobial properties of magnesium (Mg) metal and nano-magnesium oxide (nMgO) in vitro, to evaluate the in vitro cytotoxicity of Mg metal, and to incorporate MgO nanoparticles into a polymeric implant coating and evaluate its in vitro antimicrobial properties. In the course of this work it was found that Mg metal, Mg-mesh, and nMgO have in vitro antimicrobial properties that are similar to a bactericidal antibiotic. For Mg metal, the mechanism of this activity appears to be related to an increase in pH (i.e. a more alkaline environment) and not an increase in Mg2+. Given that Mg-mesh is a Mg metal powder, the assumption is that it has the same mechanism of activity as Mg metal. The mechanism of activity for nMgO remains to be elucidated and may be related to a combination of interaction of the nanoparticles with the bacteria and the alkaline pH. It was further demonstrated that supernatants from suspensions of Mg-mesh and nMgO had the same antimicrobial effect as was noted when the particles were used. The supernatant from Mg-mesh and nMgO was also noted to prevent biofilm formation for two Staphylococcus strains. Finally, poly-epsilon-caprolactone (PCL) composites of Mg-mesh (PCL+Mg-mesh) and nMgO (PCL+nMgO) were produced. Coatings applied to screws inhibited growth of Escherichia coli and Pseudomonas aeruginosa and in thin disc format inhibited the growth of Staphylococcus aureus in addition to the E. coli and P. aeruginosa. Pure Mg metal was noted to have some cytotoxic effect on murine fibroblast and osteoblast cell lines, although this effect needs to be characterized further. To address the need for an in vivo model for evaluating implant associated infections, a new closed fracture osteomyelitis model in the femur of the rat was developed. Magnesium, a readily available and inexpensive metal was shown to have antimicrobial properties that appear to be related to its corrosion products and

  19. Low brain magnesium in migraine

    SciTech Connect

    Ramadan, N.M.; Halvorson, H.; Vande-Linde, A.; Levine, S.R.; Helpern, J.A.; Welch, K.M.

    1989-10-01

    Brain magnesium was measured in migraine patients and control subjects using in vivo 31-Phosphorus Nuclear Magnetic Resonance Spectroscopy. pMg and pH were calculated from the chemical shifts between Pi, PCr and ATP signals. Magnesium levels were low during a migraine attack without changes in pH. We hypothesize that low brain magnesium is an important factor in the mechanism of the migraine attack.

  20. Magnesium ion implantation on a micro/nanostructured titanium surface promotes its bioactivity and osteogenic differentiation function.

    PubMed

    Wang, Guifang; Li, Jinhua; Zhang, Wenjie; Xu, Lianyi; Pan, Hongya; Wen, Jin; Wu, Qianju; She, Wenjun; Jiao, Ting; Liu, Xuanyong; Jiang, Xinquan

    2014-01-01

    As one of the important ions associated with bone osseointegration, magnesium was incorporated into a micro/nanostructured titanium surface using a magnesium plasma immersion ion-implantation method. Hierarchical hybrid micro/nanostructured titanium surfaces followed by magnesium ion implantation for 30 minutes (Mg30) and hierarchical hybrid micro/nanostructured titanium surfaces followed by magnesium ion implantation for 60 minutes (Mg60) were used as test groups. The surface morphology, chemical properties, and amount of magnesium ions released were evaluated by field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy, field-emission transmission electron microscopy, and inductively coupled plasma-optical emission spectrometry. Rat bone marrow mesenchymal stem cells (rBMMSCs) were used to evaluate cell responses, including proliferation, spreading, and osteogenic differentiation on the surface of the material or in their medium extraction. Greater increases in the spreading and proliferation ability of rBMMSCs were observed on the surfaces of magnesium-implanted micro/nanostructures compared with the control plates. Furthermore, the osteocalcin (OCN), osteopontin (OPN), and alkaline phosphatase (ALP) genes were upregulated on both surfaces and in their medium extractions. The enhanced cell responses were correlated with increasing concentrations of magnesium ions, indicating that the osteoblastic differentiation of rBMMSCs was stimulated through the magnesium ion function. The magnesium ion-implanted micro/nanostructured titanium surfaces could enhance the proliferation, spreading, and osteogenic differentiation activity of rBMMSCs, suggesting they have potential application in improving bone-titanium integration.

  1. Magnesium ion implantation on a micro/nanostructured titanium surface promotes its bioactivity and osteogenic differentiation function

    PubMed Central

    Wang, Guifang; Li, Jinhua; Zhang, Wenjie; Xu, Lianyi; Pan, Hongya; Wen, Jin; Wu, Qianju; She, Wenjun; Jiao, Ting; Liu, Xuanyong; Jiang, Xinquan

    2014-01-01

    As one of the important ions associated with bone osseointegration, magnesium was incorporated into a micro/nanostructured titanium surface using a magnesium plasma immersion ion-implantation method. Hierarchical hybrid micro/nanostructured titanium surfaces followed by magnesium ion implantation for 30 minutes (Mg30) and hierarchical hybrid micro/nanostructured titanium surfaces followed by magnesium ion implantation for 60 minutes (Mg60) were used as test groups. The surface morphology, chemical properties, and amount of magnesium ions released were evaluated by field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy, field-emission transmission electron microscopy, and inductively coupled plasma-optical emission spectrometry. Rat bone marrow mesenchymal stem cells (rBMMSCs) were used to evaluate cell responses, including proliferation, spreading, and osteogenic differentiation on the surface of the material or in their medium extraction. Greater increases in the spreading and proliferation ability of rBMMSCs were observed on the surfaces of magnesium-implanted micro/nanostructures compared with the control plates. Furthermore, the osteocalcin (OCN), osteopontin (OPN), and alkaline phosphatase (ALP) genes were upregulated on both surfaces and in their medium extractions. The enhanced cell responses were correlated with increasing concentrations of magnesium ions, indicating that the osteoblastic differentiation of rBMMSCs was stimulated through the magnesium ion function. The magnesium ion-implanted micro/nanostructured titanium surfaces could enhance the proliferation, spreading, and osteogenic differentiation activity of rBMMSCs, suggesting they have potential application in improving bone-titanium integration. PMID:24940056

  2. The alkalinizing effects of metabolizable bases in the healthy calf.

    PubMed Central

    Naylor, J M; Forsyth, G W

    1986-01-01

    The alkalinizing effect of citrate, acetate, propionate, gluconate, L and DL-lactate were compared in healthy neonatal calves. The calves were infused for a 3.5 hour period with 150 mmol/L solutions of the sodium salts of the various bases. Blood pH, base excess, and metabolite concentrations were measured and the responses compared with sodium bicarbonate and sodium chloride infusion. D-gluconate and D-lactate had poor alkalinizing abilities and accumulated in blood during infusion suggesting that they are poorly metabolized by the calf. Acetate, L-lactate and propionate had alkalinizing effects similar to bicarbonate, although those of acetate had a slightly better alkalinizing effect than L-lactate. Acetate was more effectively metabolized because blood acetate concentrations were lower than L-lactate concentrations. There was a tendency for a small improvement in metabolism of acetate and lactate with age. Sodium citrate infusion produced signs of hypocalcemia, presumably because it removed ionized calcium from the circulation. D-gluconate, D-lactate and citrate are unsuitable for use as alkalinizing agents in intravenous fluids. Propionate, acetate and L-lactate are all good alkalinizing agents in healthy calves but will not be as effective in situations where tissue metabolism is impaired. PMID:3024796

  3. The sulphate-reduction alkalinity pump tested

    NASA Astrophysics Data System (ADS)

    Meister, Patrick; Petrishcheva, Elena

    2016-04-01

    Carbonate precipitation has been suggested to be induced by alkalinity increase during sulphate reduction under anoxic conditions. This mechanism may explain the formation of carbonate deposits in shallow marine environments, either within a redox stratified sediment inhabited by phototrophic microbial mats or in shallow water within the photic zone where sulphidic water is upwelling onto the shelf. The alkalinity pump may work as long as the sulphide is not reoxidized to sulphate, a process that would acidify the surrounding. The alkalinity effect of sulphate reduction was recently tested by Aloisi (2008) for microbial mats using a model approach. He found that sulphate reduction does not significantly increase or even decrease carbonate saturation and is unlikely to have played a significant role through Earth history. The model considers many environmental factors, including the effect of carbonate precipitation itself on the carbonate equilbrium and on the alkalinity. We used a modified version of Aloisi's (2008) model to simulate the saturation states of aragonite, calcite and dolomite without the effects of carbonate precipitation. This is necessary to evaluate the effect of microbial metabolisms exclusively on carbonate saturation, since carbonate precipitation is only the consequence, but not the cause of oversaturation. First results show that the saturation state is increased in the zone of phototrophic CO2 uptake. In contrast, the saturation state is strongly decreased in the zone where dissolved oxygen overlaps with dissolved sulphide. Aerobic sulphide oxidation consumes most of the HS- and dissipates most of the alkalinity produced in the sulphate reduction zone below. Hence, our results are consistent with the findings of Aloisi (2008), and they even more clearly show that sulphate reduction does not induce carbonate precipitation nor contributes to carbonate precipitation in combination with phototrophic CO2 uptake. The alkalinity effect of sulphate

  4. Switchable mirrors based on nickel-magnesium films

    SciTech Connect

    Richardson,Thomas J.; Slack, Jonathan L.; Armitage, Robert D.; Kostecki, Robert; Farangis, Baker; Rubin, Michael D.

    2001-01-16

    A new type of electrochromic mirror electrode based on reversible uptake of hydrogen in nickel magnesium alloy films is reported. Thin,magnesium-rich Ni-Mg films prepared on glass substrates by cosputtering from Ni and Mg targets are mirror-like in appearance and have low visible transmittance. Upon exposure to hydrogen gas or on reduction in alkaline electrolyte, the films take up hydrogen and become transparent. When hydrogen is removed, the mirror properties are recovered. The transition is believed to result from reversible formation of Mg2NiH4 and MgH2. A thin overlayer of palladium was found to enhance the kinetics of hydrogen insertion and extraction,and to protect the metal surface against oxidation.

  5. Product development of FGD recovered magnesium hydroxide

    SciTech Connect

    Beeghly, J.H.; Babu, M.; Smith, K.J.

    1999-07-01

    The ThioClear FGD processes developed by the Dravo Lime Company (DLC) produce a high brightness gypsum and magnesium hydroxide (Mg(OH){sub 2}) by-product. Both originate as white precipitates from a solution of magnesium sulfate. The use of magnesium-enhanced lime avoids the mineral impurities from direct neutralization when using pulverized limestone rock. White, pure FGD synthetic gypsum can be used to produce higher value products such as mineral fillers and industrial plasters. This paper focuses on the product development of the Mg(OH){sub 2} by-product. Commercial Mg(OH){sub 2} sells at over $200/Ton for a variety of uses, most of which is wastewater treatment and a feedstock to make magnesium chemicals and refractories. Beneficial uses in the power plant are pH control of acidic coal pile stormwater runoff and bottom ash quench water. A future use being explored is injection into coal fired boilers to neutralize sulfur trioxide (SO{sub 3}) to prevent stack gas opacity related emission problems and minimize air preheater corrosion and fouling. The objective of this project is to improve the purity and solids content of the by-product after it is separated from the gypsum. Several options were investigated to convert it into a more marketable or usable form. Test results and economic evaluations are reported during the different process steps needed to improve the product quality: (1) dissolving or washing out the gypsum impurity; (2) thickening the washed solids and using the overflow for makeup water within the FGD water balance; (3) finding the best means to dewater the washed, thickened slurry; and (4) repulp the dewatered cake into a stabilized slurry or dry it to powder. Flash drying the dewatered cake is compared to spray drying the thickened slurry. FGD Mg(OH){sub 2} is shown to have equal reactivity as an acid neutralization reagent on a Mg(OH){sub 2} molar basis to commercial Mg(OH){sub 2} products and other alkaline reagents. Its use for pH control

  6. [Magnesium disorder in metabolic bone diseases].

    PubMed

    Ishii, Akira; Imanishi, Yasuo

    2012-08-01

    Magnesium is abundantly distributed among the body. The half of the magnesium exists in the bone. In addition, magnesium is the second most abundant intracellular cation in vertebrates and essential for maintaining physiological function of the cells. Epidemiologic studies have demonstrated that magnesium deficiency is a risk factor for osteoporosis. The mechanism of bone fragility caused by magnesium deficiency has been intensely studied using animal models of magnesium deficiency. Magnesium deficiency causes decreased osteoblastic function and increased number of osteoclasts. Magnesium deficiency also accelerates mineralization in bone. These observations suggest that disturbed bone metabolic turnover and mineralization causes bone fragility.

  7. Strontium- and magnesium-enriched biomimetic β-TCP macrospheres with potential for bone tissue morphogenesis.

    PubMed

    Chou, J; Valenzuela, S M; Santos, J; Bishop, D; Milthorpe, B; Green, D W; Otsuka, M; Ben-Nissan, B

    2014-10-01

    During the last two decades, biogenic mineral ions have become important additives in treatments for bone regeneration and repair. Prominent among these is strontium, which is a potent suppressor of osteoclast bone resorption. Another is magnesium, which has a key influence in mineralization processes. The shells of benthic foraminiferans, hydrothermally converted into β-TCP, have been shown to effectively release a number of bone-promoting drugs at clinically relevant levels. In this study we characterized the effects of converted foraminiferan calcium dissolution and the concomitant release profile of intrinsic strontium and magnesium. We tested the effects of strontium- and magnesium-enriched macrospheres on human osteoblast (SaOS-2) and monocytoid (U937) cell lines, which can be induced to express equivalent phagocytic activities to osteoclasts. On dissolution in a biomimetic physiological solution, the macrospheres released biologically significant quantities of calcium and phosphate ions in the first 18 days. At 3 days, during which biogenic mineral ions are released, the number of U937 osteoclast-like monocyte cells decreased, while 4 days later the osteoblast cell number increased. These results show that strontium and magnesium naturally enriched macrospheres are capable of altering the metabolic activities of the cells regulating bone homeostasis. These unique macrospheres are natural origin bone void filler particles that resorb, and release physiologically significant levels of incorporated strontium, magnesium and calcium, which together make a uniquely multifunctional in situ remedy for bone regeneration and repair and the treatment of bone-wasting diseases.

  8. Effect of surface area on corrosion properties of magnesium for biomaterials

    NASA Astrophysics Data System (ADS)

    Kim, Woo-Cheol; Han, Kwon-Hoon; Kim, Jung-Gu; Yang, Seok-Jo; Seok, Hyun-Kwang; Han, Hyung-Seop; Kim, Young-Yul

    2013-09-01

    This study examined the effect of the surface area on the corrosion properties of magnesium through in vivo (weight loss test) and in vitro (electrochemical and weight loss tests in Hank's solution) tests. The corrosion rate was reduced as the surface area increased. Surface analysis showed that the precipitation of calcium phosphate increased with increasing surface area. Moreover, the pH level around the specimen increased with increasing surface area. This increase of pH can accelerate the precipitation of calcium phosphate on the surface. However, different mechanism of calcium phosphate precipitation was found for in vivo and vitro test environment. In vitro environment showed an increase of calcium phosphate due to the continuous increase in pH, whereas in vivo environment showed increase of calcium phosphate to maintain homeostasis and reduced the level of pH in physiological system. Consequently, the increase in magnesium surface area leads to increase the precipitation of calcium phosphate as a more stable rust layer which ultimately increases the corrosion resistance of magnesium.

  9. Morphologies and elemental compositions of calcium crystals in phyllodes and branchlets of Acacia robeorum (Leguminosae: Mimosoideae)

    PubMed Central

    He, Honghua; Bleby, Timothy M.; Veneklaas, Erik J.; Lambers, Hans; Kuo, John

    2012-01-01

    Background and Aims Formation of calcium oxalate crystals is common in the plant kingdom, but biogenic formation of calcium sulfate crystals in plants is rare. We investigated the morphologies and elemental compositions of crystals found in phyllodes and branchlets of Acacia robeorum, a desert shrub of north-western Australia. Methods Morphologies of crystals in phyllodes and branchlets of A. robeorum were studied using scanning electron microscopy (SEM), and elemental compositions of the crystals were identified by energy-dispersive X-ray spectroscopy. Distributional patterns of the crystals were studied using optical microscopy together with SEM. Key Results According to the elemental compositions, the crystals were classified into three groups: (1) calcium oxalate; (2) calcium sulfate, which is a possible mixture of calcium sulfate and calcium oxalate with calcium sulfate being the major component; and (3) calcium sulfate · magnesium oxalate, presumably mixtures of calcium sulfate, calcium oxalate, magnesium oxalate and silica. The crystals were of various morphologies, including prisms, raphides, styloids, druses, crystal sand, spheres and clusters. Both calcium oxalate and calcium sulfate crystals were observed in almost all tissues, including mesophyll, parenchyma, sclerenchyma (fibre cells), pith, pith ray and cortex; calcium sulfate · magnesium oxalate crystals were only found in mesophyll and parenchyma cells in phyllodes. Conclusions The formation of most crystals was biologically induced, as confirmed by studying the crystals formed in the phyllodes from seedlings grown in a glasshouse. The crystals may have functions in removing excess calcium, magnesium and sulfur, protecting the plants against herbivory, and detoxifying aluminium and heavy metals. PMID:22294477

  10. The bioavailability of calcium in spinach and calcium-oxalate to calcium-deficient rats.

    PubMed

    Kikunaga, S; Arimori, M; Takahashi, M

    1988-04-01

    We estimated the utilization of calcium in spinach and calcium-oxalate to calcium-deficient rats, and the effect of oxalic acid on absorption of dietary calcium by using calcium-deficient rats. The body weight gain of the calcium-deficient rats for 8 days receiving a calcium-deficient diet supplemented with raw-powdered spinach (R-sp), boiled-powdered spinach (B-sp), or calcium-oxalate (Ca-ox), and a control diet supplemented with oxalic acid (OX-C) were 4.8, 2.8, 4.9, and 5.1 g, respectively. The calcium content in the liver and kidney of the rats receiving R-sp, B-sp, Ca-ox, and OX-C diets significantly increased as compared with the calcium-deficient rats. Significant differences in the liver calcium levels were not observed among the rats receiving various additional diets, though the content in the kidneys of the rats receiving R-sp, B-sp, Ca-ox, and OX-C diets were 28.0, 21.5, 0.11, and 0.59 mg, respectively. An especially large amount of calcium was accumulated in the kidneys of the rats receiving R-sp and B-sp diets. The calcium concentration in the serum of the rats receiving Ca-ox and OX-C diets was higher than the calcium concentration in the serum of the R-sp, B-sp, and calcium-deficient rats. The calcium content in the left tibiae of the rats receiving Ca-ox and OX-C diets was higher than that of the rats receiving R-sp and B-sp diets. The breaking force of the right tibiae of the rats was highest in the OX-C group, and higher in the R-sp and Ca-ox groups than the breaking force of the right tibiae of the rats fed on B-sp diet. The alkaline phosphatase activity in the small intestines of the rats rose in the order of the R-sp, B-sp, and Ca-ox groups, although significant differences of the activity were not observed between the Ca-ox and the OX-C groups. The calcium retention of the rats receiving the calcium-deficient, R-sp, B-sp, Ca-ox, and OX-C diets was -18.5, 35.2, 25.6, 41.6, and 45.8%, respectively. About 35% of the calcium in the spinach was

  11. Magnesium Hall Thruster

    NASA Technical Reports Server (NTRS)

    Szabo, James J.

    2015-01-01

    This Phase II project is developing a magnesium (Mg) Hall effect thruster system that would open the door for in situ resource utilization (ISRU)-based solar system exploration. Magnesium is light and easy to ionize. For a Mars- Earth transfer, the propellant mass savings with respect to a xenon Hall effect thruster (HET) system are enormous. Magnesium also can be combusted in a rocket with carbon dioxide (CO2) or water (H2O), enabling a multimode propulsion system with propellant sharing and ISRU. In the near term, CO2 and H2O would be collected in situ on Mars or the moon. In the far term, Mg itself would be collected from Martian and lunar regolith. In Phase I, an integrated, medium-power (1- to 3-kW) Mg HET system was developed and tested. Controlled, steady operation at constant voltage and power was demonstrated. Preliminary measurements indicate a specific impulse (Isp) greater than 4,000 s was achieved at a discharge potential of 400 V. The feasibility of delivering fluidized Mg powder to a medium- or high-power thruster also was demonstrated. Phase II of the project evaluated the performance of an integrated, highpower Mg Hall thruster system in a relevant space environment. Researchers improved the medium power thruster system and characterized it in detail. Researchers also designed and built a high-power (8- to 20-kW) Mg HET. A fluidized powder feed system supporting the high-power thruster was built and delivered to Busek Company, Inc.

  12. Magnesium reduction of uranium oxide

    SciTech Connect

    Elliott, G.R.B.

    1985-08-13

    A method and apparatus are provided for reducing uranium oxide with magnesium to form uranium metal. The reduction is carried out in a molten-salt solution of density greater than 3.4 grams per cubic centimeter, thereby allowing the uranium product to sink and the magnesium oxide byproduct to float, consequently allowing separation of product and byproduct.

  13. Calcium in diet

    MedlinePlus

    ... of calcium dietary supplements include calcium citrate and calcium carbonate. Calcium citrate is the more expensive form of ... the body on a full or empty stomach. Calcium carbonate is less expensive. It is absorbed better by ...

  14. Parathyroid and Calcium Status in Patients with Thalassemia

    PubMed Central

    Goyal, Meenu; Abrol, Pankaj

    2010-01-01

    Thirty patients with thalassemia major receiving repeated blood transfusion were studied to see their serum parathyroid hormone (PTH) and calcium status. Serum PTH, serum and 24 h urinary calcium, and serum alkaline phosphatase, phosphorus, and albumin-corrected calcium levels were determined. Half of these patients, in addition to transfusion, were also supplemented with vitamin D (60,000 IU for 10d) and calcium (1500 mg/day for 3 months). Serum PTH, and serum and 24 h urinary calcium concentrations of the patients receiving transfusions were found to be significantly reduced while their serum alkaline phosphatase, phosphorus, and albumin-corrected calcium levels were not significantly altered when compared to the respective mean values for the control group. Vitamin D and calcium supplementation significantly increased their serum PTH and calcium levels. Supplementations also increased urinary excretion of calcium. The results thus suggest that patients with thalassemia have hypoparathyroidism and reduced serum calcium concentrations that in turn were improved with vitamin D and calcium supplementation. PMID:21966110

  15. [Pharmacology of the extracellular calcium ion receptor].

    PubMed

    Ruat, Martial

    2003-01-01

    The calcium sensing receptor (CaSR) belongs to family 3 of G-protein coupled receptors. The CaSR, expressed at the surface of the parathyroid cells, controls parathyroid hormone (PTH) secretion and is the main regulator of calcium homeostasis. Its activity is regulated by small changes in the physiological concentrations of calcium and magnesium ions present in the serum and extracellular fluids, leading to the stimulation of the phospholipases C and A2. Molecules that potentiate the effect of extracellular calcium are called calcimimetics. They reduce the PTH level in vivo and have been proposed to be of therapeutic benefit for the treatment of both primary and secondary hyperparathyroidism. The blocking of CaSR by a calcilytic molecule results in the increase in serum PTH and might be of interest in the treatment of osteoporosis. The CaSR is also expressed in the thyroid, kidney, bone and in neuronal and glial cell populations, where it should be involved in the complex responses associated with calcium and magnesium ions present in the extracellular fluids.

  16. Magnesium substitution in brushite cements.

    PubMed

    Alkhraisat, Mohammad Hamdan; Cabrejos-Azama, Jatsue; Rodríguez, Carmen Rueda; Jerez, Luis Blanco; Cabarcos, Enrique López

    2013-01-01

    The use of magnesium-doped ceramics has been described to modify brushite cements and improve their biological behavior. However, few studies have analyzed the efficiency of this approach to induce magnesium substitution in brushite crystals. Mg-doped ceramics composed of Mg-substituted β-TCP, stanfieldite and/or farringtonite were reacted with primary monocalcium phosphate (MCP) in the presence of water. The cement setting reaction has resulted in the formation of brushite and newberyite within the cement matrix. Interestingly, the combination of SAED and EDX analyses of single crystal has indicated the occurrence of magnesium substitution within brushite crystals. Moreover, the effect of magnesium ions on the structure, and mechanical and setting properties of the new cements was characterized as well as the release of Ca(2+) and Mg(2+) ions. Further research would enhance the efficiency of the system to incorporate larger amounts of magnesium ions within brushite crystals.

  17. Magnesium in Prevention and Therapy

    PubMed Central

    Gröber, Uwe; Schmidt, Joachim; Kisters, Klaus

    2015-01-01

    Magnesium is the fourth most abundant mineral in the body. It has been recognized as a cofactor for more than 300 enzymatic reactions, where it is crucial for adenosine triphosphate (ATP) metabolism. Magnesium is required for DNA and RNA synthesis, reproduction, and protein synthesis. Moreover, magnesium is essential for the regulation of muscular contraction, blood pressure, insulin metabolism, cardiac excitability, vasomotor tone, nerve transmission and neuromuscular conduction. Imbalances in magnesium status—primarily hypomagnesemia as it is seen more common than hypermagnesemia—might result in unwanted neuromuscular, cardiac or nervous disorders. Based on magnesium’s many functions within the human body, it plays an important role in prevention and treatment of many diseases. Low levels of magnesium have been associated with a number of chronic diseases, such as Alzheimer’s disease, insulin resistance and type-2 diabetes mellitus, hypertension, cardiovascular disease (e.g., stroke), migraine headaches, and attention deficit hyperactivity disorder (ADHD). PMID:26404370

  18. Alkaline earth imidazolate coordination polymers by solvent free melt synthesis as potential host lattices for rare earth photoluminescence: (x)(∞)[AE(Im)2(ImH)(2-3)], Mg, Ca, Sr, Ba, x = 1-2.

    PubMed

    Zurawski, Alexander; Rybak, J-Christoph; Meyer, Larissa V; Matthes, Philipp R; Stepanenko, Vladimir; Dannenbauer, Nicole; Würthner, Frank; Müller-Buschbaum, Klaus

    2012-04-14

    The series of alkaline earth elements magnesium, calcium, strontium and barium yields single crystalline imidazolate coordination polymers by reactions of the metals with a melt of 1H-imidazole: (1)(∞)[Mg(Im)(2)(ImH)(3)] (1), (2)(∞)[AE(Im)(2)(ImH)(2)], AE = Ca (2), Sr (3), and (1)(∞)[Ba(Im)(2)(ImH)(2)] (4). No additional solvents were used for the reactions. Co-doping experiments by addition of the rare earth elements cerium, europium and terbium were carried out. They indicate (2)(∞)[Sr(Im)(2)(ImH)(2)] as a possible host lattice for cerium(III) photoluminescence showing a blue emission and thus a novel blue emitting hybrid material phosphor 3:Ce(3+). Co-doping with europium and terbium is also possible but resulted in formation of (3)(∞)[Sr(Im)(2)]:Ln, Ln = Eu and Tb (5), with both exhibiting green emission of either Eu(2+) or Tb(3+). The other alkaline earth elements do not show acceptance of the rare earth ions investigated and a different structural chemistry. For magnesium and barium one-dimensional strand structures are observed whereas calcium and strontium give two-dimensional network structures. Combined with an increase of the ionic radii of AE(2+) the coordinative demand is also increasing from Mg(2+) to Ba(2+), reflected by four different crystal structures for the four elements Mg, Ca, Sr, Ba in 1-4. Different linkages of the imidazolate ligands result in a change from complete σ-N coordination in 1 to additional η(5)-π coordination in 4. The success of co-doping with different lanthanide ions is based on a match in the chemical behaviour and cationic radii. The use of strontium for host lattices with imidazole is a rare example in coordination chemistry of co-doping with small amounts of luminescence centers and successfully reduces the amount of high price rare earth elements in hybrid materials while maintaining the properties. All compounds are examples of pure N-coordinated coordination polymers of the alkaline earth metals and were

  19. The flame photometric determination of calcium in phosphate, carbonate, and silicate rocks

    USGS Publications Warehouse

    Kramer, H.

    1957-01-01

    A flame photometric method of determining calcium in phosphate, carbonate, and silicate locks has been developed Aluminum and phosphate interference was overcome by the addition of a large excess of magnesium. The method is rapid and suitable for routine analysis Results obtained are within ?? 2% of the calcium oxide content. ?? 1957.

  20. Thermal behavior of bone and synthetic hydroxyapatites submitted to magnesium interaction in aqueous medium.

    PubMed

    Baravelli, S; Bigi, A; Ripamonti, A; Roveri, N; Foresti, E

    1984-01-01

    The thermal behavior of the products obtained from magnesium interaction with powdered femoral bone and carbonate containing synthetic hydroxyapatite under conditions of pH fluctuation in aqueous medium has been investigated. The products, heat treated at different temperatures from 100 to 1300 degrees C, have been characterized by infrared spectroscopy and X-ray diffraction technique. The results show that the interaction with magnesium ion destabilizes the apatitic structure and favours its thermal conversion into beta-tricalcium phosphate (beta-TCP). The replacement of magnesium with calcium in the beta-TCP crystal lattice hinders its subsequent thermal conversion into the alpha form. The influence of magnesium on the thermal stability is much more evident for carbonate-containing synthetic hydroxyapatite than for bone apatite.

  1. Effects of magnesium and chloride ions on limestone dual-alkali-system performance

    SciTech Connect

    Chang, J.C.S.; Kaplan, N.; Brna, T.G.

    1985-08-01

    The paper gives results of pilot plant tests to evaluate the effects of magnesium and chloride ions on system performance of limestone-regenerated dual alkali processes under closed-loop operating conditions. It was found that limestone reactivity and solids dewatering properties are very sensitive to magnesium ion concentrations. The total magnesium ion concentration should be maintained below 1000 ppm for satisfactory performance under normal operation. A model which assumes competitive surface adsorption of calcium and magnesium ions was used to interpret the data. Limestone reactivity and solids dewatering properties decreased with the increase of chloride ion concentrations; however, the effect of chloride ion accumulation was not significant until the concentration reached 80,000 ppm.

  2. Calcium - ionized

    MedlinePlus

    ... 245. Read More Acute kidney failure Albumin - blood (serum) test Bone tumor Calcium blood test Hyperparathyroidism Hypoparathyroidism Malabsorption Milk-alkali syndrome Multiple myeloma Osteomalacia Paget disease of the bone Rickets Sarcoidosis Vitamin D Review ...

  3. The pathogenesis of eclampsia: the 'magnesium ischaemia' hypothesis.

    PubMed

    Newman, J C; Amarasingham, J L

    1993-04-01

    'Magnesium ischaemia' is a term used to denote the functional impairment of the ATP-dependent sodium/potassium and calcium pumps in the cell membranes and within the cell itself. The production of ATP and the functioning of these pumps is magnesium-dependent and is critically sensitive to acidosis. Zinc and iron deficiencies may secondarily impair these pumps and thus contribute to 'magnesium ischaemia' (as does acidosis). This term is two-dimensional at its simplest; it refers to a functional magnesium deficiency, whether actual or induced. It is argued that chronic acidosis is the most common inducing factor. This simple hypothesis can begin to unify diverse pathophysiologies: some spontaneous abortions, aspects of Type II and gestational diabetes and the curious observation that heroin addicts become diabetic. It can also unify clinical thinking about pregnancy-induced hypertension, pre-eclampsia/eclampsia and acute fatty liver of pregnancy, as well as the coagulopathy of pregnancy. It makes important predictions about perinatal morbidity and suggests that early supplementation might prevent much pregnancy-induced disease.

  4. Magnesium in drinking water - a case for prevention?

    PubMed

    Rylander, Ragnar

    2014-03-01

    Studies in many countries have demonstrated a relationship between drinking water mineral content and the risk of death in cardiovascular disease (CVD). Particularly strong relationships have been found for magnesium and it has been suggested that magnesium be added to drinking water. The aim of this article is to evaluate the validity of this suggestion by reviewing information on possible causative agents. Major epidemiological studies on the drinking water content of calcium, magnesium, and hardness were analysed regarding exposure specificity, confounding factors, dose-response relationships and biological plausibility. Intervention experiments were analysed. The risk of death in CVD was related to the content of Ca, Mg and HCO(3-). The data demonstrate that Ca and Mg need to be considered together, and that HCO(3-) could play a role by intervening with the body acid load. There is no evidence to justify the addition of magnesium only to drinking water for preventive purposes. The data suggest that Ca and Mg could be administered together but no data are available regarding the relative proportions for an optimal effect.

  5. Calcium Carbonate.

    PubMed

    Al Omari, M M H; Rashid, I S; Qinna, N A; Jaber, A M; Badwan, A A

    2016-01-01

    Calcium carbonate is a chemical compound with the formula CaCO3 formed by three main elements: carbon, oxygen, and calcium. It is a common substance found in rocks in all parts of the world (most notably as limestone), and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. CaCO3 exists in different polymorphs, each with specific stability that depends on a diversity of variables.

  6. The Alkaline Dissolution Rate of Calcite.

    PubMed

    Colombani, Jean

    2016-07-07

    Due to the widespread presence of calcium carbonate on Earth, several geochemical systems, among which is the global CO2 cycle, are controlled to a large extent by the dissolution and precipitation of this mineral. For this reason, the dissolution of calcite has been thoroughly investigated for decades. Despite this intense activity, a consensual value of the dissolution rate of calcite has not been found yet. We show here that the inconsistency between the reported values stems mainly from the variability of the chemical and hydrodynamic conditions of measurement. The spreading of the values, when compared in identical conditions, is much less than expected and is interpreted in terms of sample surface topography. This analysis leads us to propose benchmark values of the alkaline dissolution rate of calcite compatible with all the published values, and a method to use them in various chemical and hydrodynamic contexts.

  7. Calcium Hydroxylapatite

    PubMed Central

    Yutskovskaya, Yana Alexandrovna; Philip Werschler, WM.

    2015-01-01

    Background: Calcium hydroxylapatite is one of the most well-studied dermal fillers worldwide and has been extensively used for the correction of moderate-to-severe facial lines and folds and to replenish lost volume. Objectives: To mark the milestone of 10 years of use in the aesthetic field, this review will consider the evolution of calcium hydroxylapatite in aesthetic medicine, provide a detailed injection protocol for a global facial approach, and examine how the unique properties of calcium hydroxylapatite provide it with an important place in today’s market. Methods: This article is an up-to-date review of calcium hydroxylapatite in aesthetic medicine along with procedures for its use, including a detailed injection protocol for a global facial approach by three expert injectors. Conclusion: Calcium hydroxylapatite is a very effective agent for many areas of facial soft tissue augmentation and is associated with a high and well-established safety profile. Calcium hydroxylapatite combines high elasticity and viscosity with an ability to induce long-term collagen formation making it an ideal agent for a global facial approach. PMID:25610523

  8. Calcium orthophosphates

    PubMed Central

    Dorozhkin, Sergey V.

    2011-01-01

    The present overview is intended to point the readers’ attention to the important subject of calcium orthophosphates. This type of materials is of special significance for human beings, because they represent the inorganic part of major normal (bones, teeth and antlers) and pathological (i.e., those appearing due to various diseases) calcified tissues of mammals. For example, atherosclerosis results in blood vessel blockage caused by a solid composite of cholesterol with calcium orthophosphates, while dental caries and osteoporosis mean a partial decalcification of teeth and bones, respectively, that results in replacement of a less soluble and harder biological apatite by more soluble and softer calcium hydrogenphosphates. Therefore, the processes of both normal and pathological calcifications are just an in vivo crystallization of calcium orthophosphates. Similarly, dental caries and osteoporosis might be considered an in vivo dissolution of calcium orthophosphates. Thus, calcium orthophosphates hold a great significance for humankind, and in this paper, an overview on the current knowledge on this subject is provided. PMID:23507744

  9. Synthesis of magnesium diboride by magnesium vapor infiltration process (MVIP)

    DOEpatents

    Serquis, Adriana C.; Zhu, Yuntian T.; Mueller, Frederick M.; Peterson, Dean E.; Liao, Xiao Zhou

    2003-01-01

    A process of preparing superconducting magnesium diboride powder by heating an admixture of solid magnesium and amorphous boron powder or pellet under an inert atmosphere in a Mg:B ratio of greater than about 0.6:1 at temperatures and for time sufficient to form said superconducting magnesium diboride. The process can further include exposure to residual oxygen at high synthesis temperatures followed by slow cooling. In the cooling process oxygen atoms dissolved into MgB.sub.2 segregated to form nanometer-sized coherent Mg(B,O) precipitates in the MgB.sub.2 matrix, which can act as flux pinning centers.

  10. 21 CFR 184.1443 - Magnesium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Magnesium sulfate. 184.1443 Section 184.1443 Food... Specific Substances Affirmed as GRAS § 184.1443 Magnesium sulfate. (a) Magnesium sulfate (MgSO4·7H2O, CAS... magnesium oxide, hydroxide, or carbonate with sulfuric acid and evaporating the solution to...

  11. 21 CFR 184.1431 - Magnesium oxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium oxide. 184.1431 Section 184.1431 Food and... Substances Affirmed as GRAS § 184.1431 Magnesium oxide. (a) Magnesium oxide (MgO, CAS Reg. No. 1309-48-4... powder (light) or a relatively dense white powder (heavy) by heating magnesium hydroxide or...

  12. 21 CFR 184.1426 - Magnesium chloride.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Magnesium chloride. 184.1426 Section 184.1426 Food... Specific Substances Affirmed as GRAS § 184.1426 Magnesium chloride. (a) Magnesium chloride (MgC12·6H2O, CAS... mineral bischofite. It is prepared by dissolving magnesium oxide, hydroxide, or carbonate in...

  13. Mineral resource of the month: magnesium

    USGS Publications Warehouse

    Kramer, Deborah A.

    2012-01-01

    Magnesium is the eighthmost abundant element in Earth’s crust, and the second-most abundant metal ion in seawater. Although magnesium is found in more than 60 minerals, only brucite, dolomite, magnesite and carnallite are commercially important for their magnesium content. Magnesium and its compounds also are recovered from seawater, brines found in lakes and wells, and bitterns (salts).

  14. 21 CFR 184.1431 - Magnesium oxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Magnesium oxide. 184.1431 Section 184.1431 Food... Specific Substances Affirmed as GRAS § 184.1431 Magnesium oxide. (a) Magnesium oxide (MgO, CAS Reg. No... bulky white powder (light) or a relatively dense white powder (heavy) by heating magnesium hydroxide...

  15. 21 CFR 184.1426 - Magnesium chloride.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Magnesium chloride. 184.1426 Section 184.1426 Food... Specific Substances Affirmed as GRAS § 184.1426 Magnesium chloride. (a) Magnesium chloride (MgC12·6H2O, CAS... mineral bischofite. It is prepared by dissolving magnesium oxide, hydroxide, or carbonate in...

  16. 21 CFR 184.1443 - Magnesium sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  17. 21 CFR 184.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium hydroxide. 184.1428 Section 184.1428 Food... Specific Substances Affirmed as GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide (Mg(OH)2, CAS... a white precipitate by the addition of sodium hydroxide to a water soluble magnesium salt or...

  18. 21 CFR 184.1443 - Magnesium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Magnesium sulfate. 184.1443 Section 184.1443 Food... Specific Substances Affirmed as GRAS § 184.1443 Magnesium sulfate. (a) Magnesium sulfate (MgSO4·7H2O, CAS... magnesium oxide, hydroxide, or carbonate with sulfuric acid and evaporating the solution to...

  19. 21 CFR 184.1426 - Magnesium chloride.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Magnesium chloride. 184.1426 Section 184.1426 Food... Specific Substances Affirmed as GRAS § 184.1426 Magnesium chloride. (a) Magnesium chloride (MgC12·6H2O, CAS... mineral bischofite. It is prepared by dissolving magnesium oxide, hydroxide, or carbonate in...

  20. 21 CFR 184.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Magnesium hydroxide. 184.1428 Section 184.1428... GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide (Mg(OH)2, CAS Reg. No. 1309-42-8) occurs... addition of sodium hydroxide to a water soluble magnesium salt or by hydration of reactive grades...

  1. 21 CFR 184.1431 - Magnesium oxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Magnesium oxide. 184.1431 Section 184.1431 Food... Specific Substances Affirmed as GRAS § 184.1431 Magnesium oxide. (a) Magnesium oxide (MgO, CAS Reg. No... bulky white powder (light) or a relatively dense white powder (heavy) by heating magnesium hydroxide...

  2. 21 CFR 184.1443 - Magnesium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Magnesium sulfate. 184.1443 Section 184.1443 Food... Specific Substances Affirmed as GRAS § 184.1443 Magnesium sulfate. (a) Magnesium sulfate (MgSO4·7H2O, CAS... magnesium oxide, hydroxide, or carbonate with sulfuric acid and evaporating the solution to...

  3. 21 CFR 184.1426 - Magnesium chloride.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium chloride. 184.1426 Section 184.1426 Food... Specific Substances Affirmed as GRAS § 184.1426 Magnesium chloride. (a) Magnesium chloride (MgC12·6H2O, CAS... mineral bischofite. It is prepared by dissolving magnesium oxide, hydroxide, or carbonate in...

  4. 21 CFR 184.1431 - Magnesium oxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Magnesium oxide. 184.1431 Section 184.1431 Food... Specific Substances Affirmed as GRAS § 184.1431 Magnesium oxide. (a) Magnesium oxide (MgO, CAS Reg. No... bulky white powder (light) or a relatively dense white powder (heavy) by heating magnesium hydroxide...

  5. 21 CFR 184.1431 - Magnesium oxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Magnesium oxide. 184.1431 Section 184.1431 Food... GRAS § 184.1431 Magnesium oxide. (a) Magnesium oxide (MgO, CAS Reg. No. 1309-48-4) occurs naturally as... a relatively dense white powder (heavy) by heating magnesium hydroxide or carbonate. Heating...

  6. Magnesium deficiency: What is our status

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Low magnesium intake has been implicated in a broad range of cardiometabolic conditions, including diabetes, hypertension, and cardiovascular disease. Dietary magnesium and total body magnesium status have a widely-used but imperfect biomarker in serum magnesium. Despite serum magnesium’s limitation...

  7. [Magnesium: a kardio-renal viewpoint].

    PubMed

    Brandenburg, Vincent Matthias; Kaesler, Nadine; Kramann, Rafael; Floege, Jürgen; Marx, Nikolaus

    2016-10-01

    Disturbances in magnesium homeostasis are frequent clinical conditions, particularly the prevalence of hypomagnesaemia is high. However, it remains an open question which laboratory method is optimal to assess the magnesium level in the body. Most frequently physicians measure total magnesium in serum. Many associative data from observational studies point towards an association between low magnesium levels and increased cardiovascular risk as well as increased mortality. Vice versa, normal-to-high magnesium levels in patients with advanced renal failure translate to a better outcome. The present review summarizes our knowledge on protective effects of magnesium. Additionally, we address the limited evidence supporting targeted magnesium supplementation.

  8. FURNACE INJECTION OF ALKALINE SORBENTS FOR SULFURIC ACID CONTROL

    SciTech Connect

    Gary M. Blythe

    2001-11-06

    This document summarizes progress on Cooperative Agreement DE-FC26-99FT40718, Furnace Injection of Alkaline Sorbents for Sulfuric Acid Control, during the time period April 1, 2001 through September 30, 2001. The objective of this project is to demonstrate the use of alkaline reagents injected into the furnace of coal-fired boilers as a means of controlling sulfuric acid emissions. The coincident removal of hydrochloric acid and hydrofluoric acid is also being determined, as is the removal of arsenic, a known poison for NO{sub x} selective catalytic reduction (SCR) catalysts. EPRI, the Tennessee Valley Authority (TVA), FirstEnergy Corporation, and the Dravo Lime Company are project co-funders. URS Corporation is the prime contractor. During the current period, American Electric Power (AEP) joined the project as an additional co-funder and as a provider of a host site for testing. This is the fourth reporting period for the subject Cooperative Agreement. During this period, two long-term sorbent injection tests were conducted, one on Unit 3 at FirstEnergy's Bruce Mansfield Plant (BMP) and one on Unit 1 at AEP's Gavin Station. These tests determined the effectiveness of injecting alkaline slurries into the upper furnace of the boiler as a means of controlling sulfuric acid emissions from these units. The alkaline slurries tested included commercially available magnesium hydroxide slurry (Gavin Station), and a byproduct magnesium hydroxide slurry (both Gavin Station and BMP). The tests showed that injecting either the commercial or the byproduct magnesium hydroxide slurry could achieve up to 70 to 75% sulfuric acid removal. At BMP, the overall removal was limited by the need to maintain acceptable electrostatic precipitator (ESP) particulate control performance. At Gavin Station, the overall sulfuric acid removal was limited because the furnace injected sorbent was less effective at removing SO{sub 3} formed across the SCR system installed on the unit for NO{sub x

  9. Postprandial parathyroid hormone response to four calcium-rich foodstuffs.

    PubMed

    Kärkkäinen, M U; Wiersma, J W; Lamberg-Allardt, C J

    1997-06-01

    We studied the effects of four calcium-rich foodstuffs on postprandial parathyroid hormone secretion. Four hundred milligrams calcium from either Emmental cheese, milk, sesame seeds, spinach, or calcium salt (calcium lactate gluconate + calcium carbonate) or no additional calcium (control session) were given to nine female volunteers immediately after a first blood sample (at 0900) in random order with a light standardized meal containing 37 mg Ca. Blood samples were taken at 0900 (before the calcium load), 1000, 1100, 1300, and 1500 at every study session. Urine was collected during the sessions. Serum ionized calcium, phosphate, magnesium, intact parathyroid hormone, and urinary calcium excretion were measured. The serum ionized calcium concentration increased significantly after ingesting cheese (P = 0.004, contrast analysis) or calcium salt (P = 0.05, contrast analysis) compared with the control session. Compared with the control session, the serum phosphate concentration increased after the cheese session (P = 0.004, contrast analysis) and after the milk session (P = 0.02, contrast analysis). Calcium salt (P = 0.007, contrast analysis) and cheese (P = 0.002, contrast analysis) caused a significant decline in serum intact parathyroid hormone compared with the control session. The urinary calcium excretion with cheese was 141% (P = 0.001), with milk was 107% (P = 0.004), and with calcium salt was 75% (P = 0.02) above that of the control session. Our results show that calcium from sesame seeds and spinach does not cause an acute response in calcium metabolism. Our results indicate that fermented cheese could be a better dietary source of calcium than milk when the metabolic effects of the foodstuffs are considered.

  10. Acidic Fluids Across Mars: Detections of Magnesium-Nickel Sulfates

    NASA Technical Reports Server (NTRS)

    Yen, A. S.; Ming, D. W.; Gellert, R.; Mittlefehldt, D. W.; Rampe, E. B.; Vaniman, D. T.; Thompson, L. M.; Morris, R. V.; Clark, B. C.; VanBommel, S. J.

    2017-01-01

    Calcium, magnesium and ferric iron sulfates have been detected by the instrument suites on the Mars rovers. A subset of the magnesium sulfates show clear associations with nickel. These associations indicate Ni(2+) co-precipitation with or substitution for Mg(2+) from sulfate-saturated solutions. Nickel is ex-tracted from primary rocks almost exclusively at pH values less than 6, constraining the formation of these Mg-Ni sulfates to mildly to strongly acidic conditions. There is clear evidence for aqueous alteration at the rim of Endeavour Crater (Meridiani Planum), in the Murray formation mudstone (Gale Crater), and near Home Plate (Gusev Crater). The discovery of Mg-Ni sulfates at these locations indicates a history of fluid-rock interactions at low pH.

  11. A calcium ionophore stimulating the secretion of catecholamines from the cat adrenal.

    PubMed Central

    Garcia, A G; Kirpekar, S M; Prat, J C

    1975-01-01

    1. Experiments were performed on perfused cat adrenal glands to examine the effect of a calcium ionophore A-23187 in the secretion of catecholamines. 2. Ionophore (1-10 muM) caused a dose-dependent release of catecholamines and the output was about 100-fold greater at 10 mum than at 1 mum. 3. Release of catecholamines by the ionophore was dependent on the calcium concentration of the perfusion medium. Omission of calcium blocked the response to the ionophore while excess calcium facilitated it. 4. Magnesium antagonized the secretory response to the ionophore. Excess calcium overcame the inhibitory effect of magnesium. 5. The ionophore did not modify release of catecholamines by induced splanchnic nerve stimulation. 6. The results suggest that the ionophore, like depolarization, introduces calcium into the chromaffin cell to cause release of catecholamines. PMID:1091727

  12. Confession of a Magnesium Battery.

    PubMed

    Bucur, Claudiu B; Gregory, Thomas; Oliver, Allen G; Muldoon, John

    2015-09-17

    Magnesium is an ideal metal anode that has nearly double the volumetric capacity of lithium metal with a very negative reduction potential of -2.37 vs SHE. A significant advantage of magnesium is the apparent lack of dendrite formation during charging, which overcomes major safety and performance challenges encountered with using lithium metal anodes. Here, we highlight major recent advances in nonaqueous Mg electrochemistry, notably the development of electrolytes and cathodes, and discuss some of the challenges that must be overcome to realize a practical magnesium battery.

  13. Degradation and antibacterial properties of magnesium alloys in artificial urine for potential resorbable ureteral stent applications.

    PubMed

    Lock, Jaclyn Y; Wyatt, Eric; Upadhyayula, Srigokul; Whall, Andrew; Nuñez, Vicente; Vullev, Valentine I; Liu, Huinan

    2014-03-01

    This article presents an investigation on the effectiveness of magnesium and its alloys as a novel class of antibacterial and biodegradable materials for ureteral stent applications. Magnesium is a lightweight and biodegradable metallic material with beneficial properties for use in medical devices. Ureteral stent is one such example of a medical device that is widely used to treat ureteral canal blockages clinically. The bacterial colony formation coupled with the encrustation on the stent surface from extended use often leads to clinical complications and contributes to the failure of indwelling medical devices. We demonstrated that magnesium alloys decreased Escherichia coli viability and reduced the colony forming units over a 3-day incubation period in an artificial urine (AU) solution when compared with currently used commercial polyurethane stent. Moreover, the magnesium degradation resulted in alkaline pH and increased magnesium ion concentration in the AU solution. The antibacterial and degradation properties support the potential use of magnesium-based materials for next-generation ureteral stents. Further studies are needed for clinical translation of biodegradable metallic ureteral stents.

  14. Magnesium: Engineering the Surface

    NASA Astrophysics Data System (ADS)

    Chen, X. B.; Yang, H. Y.; Abbott, T. B.; Easton, M. A.; Birbilis, N.

    2012-06-01

    Magnesium (Mg) and its alloys provide numerous benefits as lightweight materials; however, industrial deployment of Mg in most instances requires anticorrosion coatings. Engineering the Mg surface is an area that has been undergoing intense research recently. Surface engineering commences with the "pretreatment" step, which can be used to modify the surface composition and morphology, resulting in surface enrichment or depletion of alloying elements. Following this, electrochemical plating (including electro- and electroless plating) and conversion coatings have emerged as common means of coating Mg. In this study, we present the key aspects relating to the science and technology associated with pretreatment, electrochemical plating, and conversion coatings. This is followed by experimental examples of engineered surfaces of industrial relevance.

  15. Strong and tough magnesium wire reinforced phosphate cement composites for load-bearing bone replacement.

    PubMed

    Krüger, Reinhard; Seitz, Jan-Marten; Ewald, Andrea; Bach, Friedrich-Wilhelm; Groll, Jürgen

    2013-04-01

    Calcium phosphate cements are brittle biomaterials of low bending strength. One promising approach to improve their mechanical properties is reinforcement with fibers. State of the art degradable reinforced composites contain fibers made of polymers, resorbable glass or whiskers of calcium minerals. We introduce a new class of composite that is reinforced with degradable magnesium alloy wires. Bending strength and ductility of the composites increased with aspect ratio and volume content of the reinforcements up to a maximal bending strength of 139±41MPa. Hybrid reinforcement with metal and polymer fibers (PLA) further improved the qualitative fracture behavior and gave indication of enhanced strength and ductility. Immersion tests of composites in SBF for seven weeks showed high corrosion stability of ZEK100 wires and slow degradation of the magnesium calcium phosphate cement by struvite dissolution. Finally, in vitro tests with the osteoblast-like cell line MG63 demonstrate cytocompatibility of the composite materials.

  16. Engineering challenges of ocean alkalinity enhancement

    NASA Astrophysics Data System (ADS)

    Kruger, T.; Renforth, P.

    2012-04-01

    The addition of calcium oxide (CaO) to the ocean as a means of enhancing the capacity of the ocean as a carbon sink was first proposed by Haroon Kheshgi in 1995. Calcium oxide is created by heating high purity limestone in a kiln to temperatures of approximately 1000°C. Addition of this material to the ocean draws carbon dioxide out of the atmosphere (approximately 1 tonne of CaO could sequester 1.3 tonnes of CO2). Abiotic carbonate precipitation is inhibited in the surface ocean. This is a carbon and energy expensive process, where approximately 0.8 tonnes of CO2 are produced at a point source for every tonne sequestered. The feasibility of ocean alkalinity enhancement requires capture and storage of the point source of CO2. We present details of a feasibility study of the engineering challenges of Kheshgi's method focusing on the potential scalability and costs of the proposed process. To draw down a PgC per year would require the extraction and processing of ~6Pg of limestone per year, which is similar in scale to the current coal industry. Costs are estimated at ~USD30-40 per tonne of CO2 sequestered through the process, which is favourable to comparative processes. Kheshgi, H. (1995) Energy 20 (9) 915-922

  17. Spectrophotometric Titration of a Mixture of Calcium and Magnesium.

    ERIC Educational Resources Information Center

    Fulton, Robert; And Others

    1986-01-01

    Describes a spectrophotometric titration experiment which uses a manual titration spectrophotometer and manually operated buret, rather than special instrumentation. Identifies the equipment, materials, and procedures needed for the completion of the experiment. Recommends the use of this experiment in introductory quantitative analysis…

  18. Crystal structure of complex natural aluminum magnesium calcium iron oxide

    SciTech Connect

    Rastsvetaeva, R. K. Aksenov, S. M.; Verin, I. A.

    2010-07-15

    The structure of a new natural oxide found near the Tashelga River (Eastern Siberia) was studied by X-ray diffraction. The pseudo-orthorhombic unit cell parameters are a = 5.6973(1) A, b = 17.1823(4) A, c = 23.5718(5) A, {beta} = 90{sup o}, sp. gr. Pc. The structure was refined to R = 0.0516 based on 4773 reflections with vertical bar F vertical bar > 7{sigma}(F) taking into account the twin plane perpendicular to the z axis (the twin components are 0.47 and 0.53). The crystal-chemical formula (Z = 4) is Ca{sub 2}Mg{sub 2}{sup IV}Fe{sub 2}{sup (2+)IV}[Al{sub 14}{sup VI}O{sub 31}(OH)][Al{sub 2}{sup IV}O][Al{sup IV}]AL{sup IV}(OH)], where the Roman numerals designate the coordination of the atoms. The structure of the mineral is based on wide ribbons of edge-sharing Al octahedra (an integral part of the spinel layer). The ribbons run along the shortest x axis and are inclined to the y and z axes. The adjacent ribbons are shifted with respect to each other along the y axis, resulting in the formation of step-like layers in which the two-ribbon thickness alternates with the three-ribbon thickness. Additional Al octahedra and Mg and Fe{sup 2+} tetrahedra are located between the ribbons. The layers are linked together to form a three-dimensional framework by Al tetrahedra, Ca polyhedra, and hydrogen bonds with the participation of OH groups.

  19. Antimicrobial properties and dentin bonding strength of magnesium phosphate cements.

    PubMed

    Mestres, G; Abdolhosseini, M; Bowles, W; Huang, S-H; Aparicio, C; Gorr, S-U; Ginebra, M-P

    2013-09-01

    The main objective of this work was to assess the antimicrobial properties and the dentin-bonding strength of novel magnesium phosphate cements (MPC). Three formulations of MPC, consisting of magnesium oxide and a phosphate salt, NH4H2PO4, NaH2PO4 or a mixture of both, were evaluated. As a result of the setting reaction, MPC transformed into either struvite (MgNH4PO4·6H2O) when NH4H2PO4 was used or an amorphous magnesium sodium phosphate when NaH2PO4 w