Struvite pyrolysate recycling combined with dry pyrolysis for ammonium removal from wastewater.

Science.gov (United States)

Yu, Rongtai; Geng, Jinju; Ren, Hongqiang; Wang, Yanru; Xu, Ke

2013-03-01

The dry pyrolysis of magnesium ammonium phosphate (MAP) with NaOH powder for ammonium release was investigated, as well as the utility of MAP pyrolysate recycling. The identities of the MAP pyrolysate and its derivatives were experimentally validated. The results showed that the pyrolysate was amorphous magnesium hydrogen phosphate (MgHPO4) and magnesium pyrophosphate (Mg2P2O7). The best molar ratio of sodium hydroxide (NaOH) powder to ammonium was 1:1, at 110°C for 3h. The optimum pH for pyrolysate recycling was 9.5. The ammonia removal ratio could be maintained above 80% with MAP pyrolysate recycling. Seed crystal inoculation increased the rate of MAP crystallization by 20.86%, as well as the MAP grain size (2.08nm with seeding versus 1.72nm without). MAP particle size with NaOH treatment decreased: d(0.5)=19.34μm versus d(0.5)=30.35μm for direct pyrolysis. The results demonstrated that crystal growth was controlled by adding NaOH during MAP pyrolysis. Copyright © 2013 Elsevier Ltd. All rights reserved.

A clinical study of serum phosphate and magnesium in type II diabetes mellitus

Directory of Open Access Journals (Sweden)

Revathi.R, Julius Amaldas

2014-11-01

Full Text Available To assess serum phosphate and magnesium level in type-2 diabetic patients in comparison with those of control subjects. Methodology: There were 100 diabetic patients and 100 age matched non-diabetic (control subjects included in this study. Serum phosphate, serum magnesium and fasting and postprandial blood sugar measured among the diabetic and control groups using SPSS version 16.0 for analysis. Results: Serum phosphate level was significantly lower in diabetic patients (2.92 ± 0.75 as compared to control subjects (3.38 ± 0.49. Serum magnesium levels were significantly lower in diabetic patients (0.9 ± 0.15 compared to controls (2.75 ± 0.46 Conclusion: The study reveals that hyperglycemia may reduce serum levels of magnesium and phosphorus.

Effects of magnesium sulfate on the foliar absorption of phosphates at the pumpkin

International Nuclear Information System (INIS)

Chamel, A.

1962-01-01

The foliar absorption of phosphates labelled with 32 P and applied with or without magnesium sulfate on the first leaf of pumpkin seedlings have been studied. The magnesium sulfate applied with the phosphate reduces plainly the absorption rate of 32 P. (O.M.) [fr

Serum phosphate and magnesium in children recovering from severe acute undernutrition in Ethiopia

DEFF Research Database (Denmark)

Hother, Anne-Louise; Girma, Tsinuel; Rytter, Maren Johanne Heilskov

2016-01-01

BACKGROUND: Children with severe acute malnutrition (SAM) have increased requirements for phosphorus and magnesium during recovery. If requirements are not met, the children may develop refeeding hypophosphatemia and hypomagnesemia. However, little is known about the effect of current therapeutic...... diets (F-75 and F-100) on serum phosphate (S-phosphate) and magnesium (S-magnesium) in children with SAM. METHODS: Prospective observational study, with measurements of S-phosphate and S-magnesium at admission, prior to rehabilitation phase and at discharge in children aged 6-59 months admitted with SAM...... to Jimma Hospital, Ethiopia. Due to shortage of F-75, 25 (35 %) children were stabilized with diluted F-100 (75 kcal/100 ml). RESULTS: Of 72 children enrolled, the mean age was 32 ± 14 months, and edema was present in 50 (69 %). At admission, mean S-phosphate was 0.92 ± 0.34 mmol/L, which was low compared...

Precipitation of ammonium from concentrated industrial wastes as struvite: a search for the optimal reagents.

Science.gov (United States)

Borojovich, Eitan J C; Münster, Meshulam; Rafailov, Gennady; Porat, Ze'ev

2010-07-01

Precipitation of struvite (MgNH4PO4) is a known process for purification of wastewater from high concentrations of ammonium. The optimal conditions for precipitation are basic pH (around 9) and sufficient concentrations of magnesium and phosphate ions. In this work, we accomplished efficient precipitation of ammonium from concentrated industrial waste stream by using magnesium oxide (MgO) both as a source of magnesium ions and as a base. Best results were obtained with technical-grade MgO, which provided 99% removal of ammonium. Moreover, ammonium removal occurred already at pH 7, and the residual ammonium concentration (50 mg/L) remained constant upon addition of more MgO without rising again, as occurs with sodium hydroxide (NaOH). This process may have two other advantages; it also can be relevant for the problem of uncontrolled precipitation of struvite in the supernatant of anaerobic sludge treatment plants, and the precipitate can be used as a fertilizer.

Development of zirconium/magnesium phosphate composites for immobilization of fission products

International Nuclear Information System (INIS)

Singh, D.; Tlustochowicz, M.; Wagh, A.S.

1999-01-01

Novel chemically bonded phosphate ceramics have been investigated for the capture and stabilization of volatile fission-product radionuclides. The authors have used low-temperature processing to fabricate zirconium phosphate and zirconium/magnesium phosphate composites. A zirconium/magnesium phosphate composite has been developed and shown to stabilize ash waste that has been contaminated with a radioactive surrogate of the 137 Cs and 90 Sr species. Excellent retention of cesium in the phosphate matrix system was observed in both short- and long-term leaching tests. The retention factor determined by the USEPA Toxicity Characteristic Leaching Procedure was one order of magnitude better for cesium that for strontium. The effective diffusivity, at room temperature, for cesium and strontium in the waste forms was estimated to be as low as 2.4 x 10 -13 and 1.2 x 10 -11 m 2 /s, respectively. This behavior was attributed to the capture of cesium in the layered zirconium phosphate structure via an intercalation ion-exchange reaction, followed by microencapsulation. However, strontium is believed to be precipitated out in its phosphate form and subsequently microencapsulated in the phosphate ceramic. The performance of these final waste forms, as indicated by the compression strength and the durability in aqueous environments, satisfies the regulatory criteria

Magnesium prevents phosphate-induced vascular calcification via TRPM7 and Pit-1 in an aortic tissue culture model.

Science.gov (United States)

Sonou, Tomohiro; Ohya, Masaki; Yashiro, Mitsuru; Masumoto, Asuka; Nakashima, Yuri; Ito, Teppei; Mima, Toru; Negi, Shigeo; Kimura-Suda, Hiromi; Shigematsu, Takashi

2017-06-01

Previous clinical and experimental studies have indicated that magnesium may prevent vascular calcification (VC), but mechanistic characterization has not been reported. This study investigated the influence of increasing magnesium concentrations on VC in a rat aortic tissue culture model. Aortic segments from male Sprague-Dawley rats were incubated in serum-supplemented high-phosphate medium for 10 days. The magnesium concentration in this medium was increased to demonstrate its role in preventing VC, which was assessed by imaging and spectroscopy. The mineral composition of the calcification was analyzed using Fourier transform infrared (FTIR) spectroscopic imaging, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) mapping. Magnesium supplementation of high-phosphate medium dose-dependently suppressed VC (quantified as aortic calcium content), and almost ablated it at 2.4 mm magnesium. The FTIR images and SEM-EDX maps indicated that the distribution of phosphate (as hydroxyapatite), phosphorus and Mg corresponded with calcium content in the aortic ring and VC. The inhibitory effect of magnesium supplementation on VC was partially reduced by 2-aminoethoxy-diphenylborate, an inhibitor of TRPM7. Furthermore, phosphate transporter-1 (Pit-1) protein expression was increased in tissues cultured in HP medium and was gradually-and dose dependently-decreased by magnesium. We conclude that a mechanism involving TRPM7 and Pit-1 underpins the magnesium-mediated reversal of high-phosphate-associated VC.

Crystal Analysis of Multi Phase Calcium Phosphate Nanoparticles Containing Different amount of Magnesium

Science.gov (United States)

Gozalian, Afsaneh; Behnamghader, Ali Asghar; Moshkforoush, Arash

In this study, Mg doped hydroxyapatite [(Ca, Mg)10(PO4)6(OH)2] and β-tricalcium phosphate nanoparticles were synthesized via sol gel method. Triethyl phosphite, calcium nitrate tetrahydrate and magnesium nitrate hexahydrate were used as P, Ca and Mg precursors. The ratio of (Ca+Mg)/P and the amount of magnesium (x) were kept constant at 1.67 and ranging x = 0 up to 3 in molecular formula of Ca10-xMgx (PO4)6(OH)2, respectively. Phase composition and chemical structure were performed using X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR). Phase percentages, crystallite size, degree of crystallinity and lattice parameters were investigated. The presence of magnesium led to form the Mg doped tricalcium phosphate (β-TCMP) and Mg doped hydroxyapatite (Mg-HA). Based on the results of this study, lattice parameters, degree of crystallinity and crystallite size decreased with magnesium content. In addition, with increasing magnesium content, the amount of CaO phase decreased whereas the amount of MgO phase increased significantly. Obtained results can be used for new biomaterials design.

Characterization of magnesium phosphate ceramics incorporating off-gas filters

International Nuclear Information System (INIS)

Yang, Jae Hwan; Lee, Chang Hwa; Heo, Chul Min; Jeon, Min Ku; Kang, Kweon Ho

2011-01-01

Radioactive cesium (Cs-137) and technetium (Tc-99) are discharged from the spent fuel as gaseous forms during the head-end process in pyroprocess. These off-gases are safely trapped via porous ceramic filters made of fly ash and calcium based material. Spent filters have to be treated, converted into proper waste forms in order to be disposed safely at a repository. Conventional technology used to make waste forms such as vitrification requires high temperature and complex process. In this study, we report a promising method to stabilize spent filters containing cesium and technetium using magnesium phosphate ceramics. Simulated spent filters were fabricated by vaporizing nonradioactive cesium and rhenium (a surrogate of Tc) through the voloxidizer. The crushed filters were mixed with raw materials of magnesium phosphate ceramics, to be stabilized in the phosphate ceramic matrix. Characterization of the waste forms was made by the compressive strength test, apparent porosity, XRD analysis, and SEM analysis. The sample containing filters showed the excellent mechanical property, with the highest compressive strength of 38.1 MPa in the sample with 30 wt% of Cs-filter. Microstructural analysis suggests that wastes are embedded in the crystalline phase formed by an acid-base reaction. (author)

Phosphate limitation in biological rapid sand filters used to remove ammonium from drinking water

DEFF Research Database (Denmark)

Lee, Carson Odell; Albrechtsen, Hans-Jørgen; Smets, Barth F.

2013-01-01

Removing ammonium from drinking water is important for maintaining biological stability in distribution systems. This is especially important in regions that do not use disinfectants in the treatment process or keep a disinfectant residual in the distribution system. Problems with nitrification c...... a pilot scale sand column which initial analysis confirmed performed similarly to the full scale filters. Long term increased ammonium loads were applied to the pilot filter both with and without phosphate addition. Phosphate was added at a concentration of 0.5 mg PO4-P/L to ensure...

Magnesium modifies the association between serum phosphate and the risk of progression to end-stage kidney disease in patients with non-diabetic chronic kidney disease.

Science.gov (United States)

Sakaguchi, Yusuke; Iwatani, Hirotsugu; Hamano, Takayuki; Tomida, Kodo; Kawabata, Hiroaki; Kusunoki, Yasuo; Shimomura, Akihiro; Matsui, Isao; Hayashi, Terumasa; Tsubakihara, Yoshiharu; Isaka, Yoshitaka; Rakugi, Hiromi

2015-10-01

It is known that magnesium antagonizes phosphate-induced apoptosis of vascular smooth muscle cells and prevents vascular calcification. Here we tested whether magnesium can also counteract other pathological conditions where phosphate toxicity is involved, such as progression of chronic kidney disease (CKD). We explored how the link between the risk of CKD progression and hyperphosphatemia is modified by magnesium status. A post hoc analysis was run in 311 non-diabetic CKD patients who were divided into four groups according to the median values of serum magnesium and phosphate. During a median follow-up of 44 months, 135 patients developed end-stage kidney disease (ESKD). After adjustment for relevant clinical factors, patients in the lower magnesium-higher phosphate group were at a 2.07-fold (95% CI: 1.23-3.48) risk for incident ESKD and had a significantly faster decline in estimated glomerular filtration rate compared with those in the higher magnesium-higher phosphate group. There were no significant differences in the risk of these renal outcomes among the higher magnesium-higher phosphate group and both lower phosphate groups. Incubation of tubular epithelial cells in high phosphate and low magnesium medium in vitro increased apoptosis and the expression levels of profibrotic and proinflammatory cytokine; these changes were significantly suppressed by increasing magnesium concentration. Thus, magnesium may act protectively against phosphate-induced kidney injury.

Phosphate conversion coating reduces the degradation rate and suppresses side effects of metallic magnesium implants in an animal model.

Science.gov (United States)

Rahim, Muhammad Imran; Tavares, Ana; Evertz, Florian; Kieke, Marc; Seitz, Jan-Marten; Eifler, Rainer; Weizbauer, Andreas; Willbold, Elmar; Jürgen Maier, Hans; Glasmacher, Birgit; Behrens, Peter; Hauser, Hansjörg; Mueller, Peter P

2017-08-01

Magnesium alloys have promising mechanical and biological properties for the development of degradable implants. However, rapid implant corrosion and gas accumulations in tissue impede clinical applications. With time, the implant degradation rate is reduced by a highly biocompatible, phosphate-containing corrosion layer. To circumvent initial side effects after implantation it was attempted to develop a simple in vitro procedure to generate a similarly protective phosphate corrosion layer. To this end magnesium samples were pre-incubated in phosphate solutions. The resulting coating was well adherent during routine handling procedures. It completely suppressed the initial burst of corrosion and it reduced the average in vitro magnesium degradation rate over 56 days almost two-fold. In a small animal model phosphate coatings on magnesium implants were highly biocompatible and abrogated the appearance of gas cavities in the tissue. After implantation, the phosphate coating was replaced by a layer with an elemental composition that was highly similar to the corrosion layer that had formed on plain magnesium implants. The data demonstrate that a simple pre-treatment could improve clinically relevant properties of magnesium-based implants. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1622-1635, 2017. © 2016 Wiley Periodicals, Inc.

32P tracer studies on the efficiency of ammonium nitrate phosphates and polyphosphates for growing rice on different soil types

International Nuclear Information System (INIS)

Sadanandan, A.K.; Mohanty, S.K.; Patnaik, S.; Mistry, K.B.

1980-01-01

A pot experiment was conducted with 32 P tagged phosphates to evaluate the efficiency of ammonium nitrate phosphate containing 30, 50 and 70 percent of P in the water soluble form, tri- and tetra-ammonium pyrophosphate, as compared with mono-ammonium ortho-phosphate (MAP) for growing rice on red, laterite and black soils, with regard to recovery of applied P in soil, dry matter production and utilization of applied P by crop at flowering and grain and straw yield at harvest. Ammonium nitrate phosphates containing 50 percent or more of P in the water soluble form could be used for growing rice on all soil types. The pyrophosphates were as efficient as MAP on soils having pH 6.2 and above but less efficient in soils of lower pH. (author)

Sorption of ammonium and phosphate from aqueous solution by biochar derived from phytoremediation plants

Institute of Scientific and Technical Information of China (English)

Zheng ZENG; Muhammad Tariq RAFIQ; Song-da ZHANG; Ting-qiang LI; Feng-liang ZHAO; Zhen-li HE; He-ping ZHAO; Xiao-e YANG; Hai-long WANG; Jing ZHAO

2013-01-01

The study on biochar derived from plant biomass for environmental applications is attracting more and more attention. Twelve sets of biochar were obtained by treating four phytoremediation plants, Salix rosthorni Seemen, Thalia dealbata, Vetiveria zizanioides, and Phragmites sp., sequential y through pyrolysis at 500 °C in a N2 environ-ment, and under different temperatures (500, 600, and 700 °C) in a CO2 environment. The cation exchange capacity and specific surface area of biochar varied with both plant species and pyrolysis temperature. The magnesium (Mg) content of biochar derived from T. dealbata (TC) was obviously higher than that of the other plant biochars. This bi-ochar also had the highest sorption capacity for phosphate and ammonium. In terms of biomass yields, adsorption capacity, and energy cost, T. dealbata biochar produced at 600 °C (TC600) is the most promising sorbent for removing contaminants (N and P) from aqueous solution. Therefore, T. dealbata appears to be the best candidate for phyto-remediation application as its biomass can make a good biochar for environmental cleaning.

Erosion of magnesium potassium phosphate ceramic waste forms

International Nuclear Information System (INIS)

Goretta, K. C.

1998-01-01

Phosphate-based chemically bonded ceramics were formed from magnesium potassium phosphate (MKP) binder and either industrial fly ash or steel slag. The resulting ceramics were subjected to solid-particle erosion by a stream of either angular Al 2 O 3 particles or rounded SiO 2 sand. Particle impact angles were 30 or 90degree and the impact velocity was 50 m/s. Steady-state erosion rates, measured as mass lost from a specimen per mass of impacting particle, were dependent on impact angle and on erodent particle size and shape. Material was lost by a combination of fracture mechanisms. Evolution of H 2 O from the MKP phase appeared to contribute significantly to the material loss

/sup 32/P tracer studies on the efficiency of ammonium nitrate phosphates and polyphosphates for growing rice on different soil types

Energy Technology Data Exchange (ETDEWEB)

Sadanandan, A K; Mohanty, S K; Patnaik, S [Central Rice Research Inst., Cuttack (India); Mistry, K B [Bhabha Atomic Research Centre, Bombay (India). Biology and Agriculture Div.

1980-12-01

A pot experiment was conducted with /sup 32/P tagged phosphates to evaluate the efficiency of ammonium nitrate phosphate containing 30, 50 and 70 percent of P in the water soluble form, tri- and tetra-ammonium pyrophosphate, as compared with mono-ammonium ortho-phosphate (MAP) for growing rice on red, laterite and black soils, with regard to recovery of applied P in soil, dry matter production and utilization of applied P by crop at flowering and grain and straw yield at harvest. Ammonium nitrate phosphates containing 50 percent or more of P in the water soluble form could be used for growing rice on all soil types. The pyrophosphates were as efficient as MAP on soils having pH 6.2 and above but less efficient in soils of lower pH.

Erosion of magnesium potassium phosphate ceramic waste forms.

Energy Technology Data Exchange (ETDEWEB)

Goretta, K. C.

1998-11-20

Phosphate-based chemically bonded ceramics were formed from magnesium potassium phosphate (MKP) binder and either industrial fly ash or steel slag. The resulting ceramics were subjected to solid-particle erosion by a stream of either angular Al{sub 2}O{sub 3} particles or rounded SiO{sub 2} sand. Particle impact angles were 30 or 90{degree} and the impact velocity was 50 m/s. Steady-state erosion rates, measured as mass lost from a specimen per mass of impacting particle, were dependent on impact angle and on erodent particle size and shape. Material was lost by a combination of fracture mechanisms. Evolution of H{sub 2}O from the MKP phase appeared to contribute significantly to the material loss.

Novel synthesis of magnesium hydroxide nanoparticles modified with organic phosphate and their effect on the flammability of acrylonitrile-butadiene styrene nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Attia, Nour F., E-mail: drnour2005@yahoo.com [Fire Protection Laboratory, Chemistry Division, National Institute of Standards, 136, Giza 12211 (Egypt); Goda, Emad S.; Nour, M.A. [Fire Protection Laboratory, Chemistry Division, National Institute of Standards, 136, Giza 12211 (Egypt); Sabaa, M.W. [Chemistry Department, Faculty of Science, Cairo University, NahdetMisr Street, Giza 12613 (Egypt); Hassan, M.A., E-mail: Mohamed_a_hassan@hotmail.com [Fire Protection Laboratory, Chemistry Division, National Institute of Standards, 136, Giza 12211 (Egypt)

2015-11-15

New and facile method for the synthesis and modification of magnesium hydroxide nanoparticles has been developed. The organic phosphate was used to facilitate the synthesis and wrapping of magnesium hydroxide nanoparticles with organic phosphate shell. The size of the nanoparticles wrapped with phosphate has an average diameter range from 46 to 125 nm. The preparation method has governed the nanoparticles diameter based on reaction time. Thermal stability and morphological properties of the new nanoparticles coated phosphates were investigated. The developed magnesium hydroxide nanoparticles-organic phosphate achieved a very good compatibility when dispersed in acrylonitrile-butadiene styrene polymer (ABS) produced dispersed nanocomposites. The flammability and thermal properties of the new polymer nanocomposites were studied. The rate of burning of the nanocomposites was reduced to 9.8 mm/min compared to 15, 21.9 and 42.5 mm/min for polymer-conventional magnesium hydroxide composite, polymer-conventional magnesium hydroxide-organic phosphate composite and virgin polymer, respectively. The peak heat release rate (PHRR) and total heat release (THR) of the new nanocomposites were recorded as 243.4 kW/m{sup 2} and 19.2 MJ/m{sup 2}, respectively, achieved 71% reduction for PHRR and 55% for THR. The synergism between magnesium hydroxide nanoparticles and organic phosphates shell was also studied. The developed nanoparticles suppressed the emission of toxic gases. The different materials were characterized using thermal gravimetric analysis, fourier transform infrared spectroscopy, transmission electron microscopy. The flammability properties were evaluated using UL94 horizontal method and cone calorimeter. The dispersion of magnesium hydroxide nanoparticles-organic phosphate in ABS was studied using scanning electron microscope. - Highlights: • Novel and facile nanoparticles synthesis and modification have developed. • Magnesium hydroxide nanoparticles size has

Electronic absorption spectrum of copper-doped magnesium potassium phosphate hexahydrate

Science.gov (United States)

Rao, S. N.; Sivaprasad, P.; Reddy, Y. P.; Rao, P. S.

1992-04-01

The optical absorption and EPR spectra of magnesium potassium phosphate hexahydrate (MPPH) doped with copper ions are recorded both at room and liquid nitrogen temperatures. The spectrum is characteristic of Cu2+ in tetragonal symmetry. The spin-Hamiltonian parameters and molecular orbital coefficients are evaluated. A correlation between EPR and optical absorption studies is drawn.

Phonon assisted electronic transition in telluric acid ammonium phosphate single crystals

Science.gov (United States)

El-Muraikhi, M.; Kassem, M. E.; Al-Houty, L.

The effect of gamma-irradiation on the absorption optical spectra of telluric acid ammonium phosphate single crystals (TAAP) has been studied, in the wave length of 200-600 nm, for samples irradiated by various doses up to 10 Mrad. The results show that the electron phonon coupling constant increases with the irradiation dose.

Relative biological activity of amorphous calcium and calcium-magnesium phosphates

International Nuclear Information System (INIS)

Silina, E.N.; Kunitsa, T.N.; Shuslikova, E.S.; Griggs, J.; Levchenko, L.V.; Karjaubaeva, R.A.; Sinyayev, V.A.

2005-01-01

Three amorphous calcium and calcium-magnesium phosphates that are close on composition to mineral basis of the bone tissues are compared on bioactivity in the given article. Properties of the hydrated substances produced from water solutions and their derivations, which are formed due to thermal treatment, are discussed here. As a detector of bioactivity was used microbial culture E-Coli. [author

Chemical synthesis and characterization of magnesium substituted amorphous calcium phosphate (MG-ACP)

Energy Technology Data Exchange (ETDEWEB)

Lee, Donghyun [Department of Biomedical Engineering, Chung-Ang University, 221 Heukseok-Dong, Dongjak-Gu, Seoul 156-756 (Korea, Republic of); Kumta, Prashant N., E-mail: pkumta@pitt.edu [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Department of Mechanical Engineering and Materials Sceince, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15260 (United States)

2010-10-12

Amorphous calcium phosphate (ACP) was synthesized by a simple aqueous precipitation using CaCl{sub 2} and Na{sub 3}PO{sub 4} in the presence of MgCl{sub 2} to ensure the formation of the ACP phase at room temperature. Magnesium substituted ACP phases corresponding to two different compositions representing the two most prominent calcium phosphate phases (hydroxyapatite: Ca + Mg/P = 1.67 and tricalcium phosphate: Ca + Mg/P = 1.5) were synthesized by this simple approach. Both compositions of ACP phases resulted in their transformation into {beta}-tricalcium phosphate upon heat treatment in air at 600 deg. C. X-ray diffraction (XRD), heat treatment, scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) and Brunauer-Emmett-Teller (BET) analyses were used to characterize the phase, thermal stability, surface area, and morphology of the synthesized ACP powders corresponding to the two different nominal Ca/P compositions. Although it is known that {alpha}-TCP is the phase that appears upon heat treatment at 600 deg. C unsubstituted ACP, substitution of magnesium ion in ACP (both TCP and HA composition) stabilized the structure of {beta}-TCMP phase at 600 deg. C. Moreover, FT-IR analysis revealed that the ACP phase regardless of the composition, exhibited characteristic bands corresponding to that of HA, with the exception of the ACP corresponding to HA composition which exhibited a prominent OH vibrational mode.

A randomized prospective triaI comparing oral sodium phosphate with magnesium citrate in preparing of patients for double contrast barium enema

International Nuclear Information System (INIS)

Lee, Eun Joo; Lee, Sung Woo; Lee, Hyeon Kyeong; Yang, Chang Hun; Kim, Soon; Oh, Yoen Hee; Kim, Seung Hyeon

2004-01-01

The purpose of this study was to compare two bowel preparation agents, sodium phosphate solution with magnesium citrate solution. A total of 94 subjects that underwent a double-contrast barium enema were included in this study. Bowel preparation before performing the barium study was done by using a sodium phosphate solution in 47 subjects and by using a magnesium citrate solution in the other 47 subjects. We evaluated the presence or absence of side effects when using these bowel preparation agents. Two radiologist who were blinded to the type of bowel preparation evaluated the quality of bowel preparation at the colonic segments (ascending, descending, and sigmoid colon) on the radiographs obtained by double-contrast barium enema, with regard to stool cleansing, water retention, barium coating and bubble formation. The side effects, such as abdominal clamping pain, nausea, hunger pain and chill occurred more frequently in the sodium phosphate group than in the magnesium citrate group (p< 0.001). Stool retention was more frequently found in the magnesium citrate group (p< 0.001). However, no statistical difference was noted on the status of water retention and barium coating between two groups. Gas bubble formation was more commonly seen in the sodium phosphate group (p< 0.001). The sodium phosphate solution appeared to be more effective in cleansing the right colon (p=0.001). Sodium phosphate solution appears to be more effective for colonic cleansing, with a lower incidence of side effects, than when using magnesium citrate solution

Strontium and magnesium substituted dicalcium phosphate dehydrate coating for carbon/carbon composites prepared by pulsed electrodeposition

Energy Technology Data Exchange (ETDEWEB)

Liu, Shou-jie, E-mail: jlliushoujie@126.com; Li, He-jun, E-mail: lihejun@nwpu.edu.cn; Zhang, Lei-lei, E-mail: zhangleilei@nwpu.edu.cn; Feng, Lei, E-mail: fengleijinan@163.com; Yao, Pei, E-mail: 1113923884@qq.com

2015-12-30

Graphical abstract: The potentiodynamic polarization curve shows that the SM-DCPD coating can dramatically enhance the corrosion potential (E{sub corr}) value and meanwhile decrease the corrosion current density (I{sub corr}) of C/C composites. - Highlights: • Strontium and magnesium substituted dicalcium phosphate dehydrate coatings for carbon/carbon composites were synthesized by pulsed eletrodeposition. • Strontium and magnesium substituted dicalcium phosphate dehydrate coated carbon/carbon composites exhibited excellent bioactivity in vivo. • Strontium and magnesium substituted dicalcium phosphate dehydrate coated carbon/carbon composites showed lower corrosion rate with the comparison to pure carbon/carbon composites. - Abstract: Trace elements substituted apatite coatings have received a lot of interest recently as they have many benefits. In this work, strontium and magnesium substituted DCPD (SM-DCPD) coatings were deposited on carbon/carbon (C/C) composites by pulsed electrodeposition method. The morphology, microstructure, corrosion resistance and in vitro bioactivity of the SM-DCPD coatings are analyzed. The results show that the SM-DCPD coatings exhibit a flake-like morphology with dense and uniform structure. The SM-DCPD coatings could induce the formation of apatite layers on their surface in simulated body fluid. The electrochemical test indicates that the SM-DCPD coatings can evidently decrease the corrosion rate of the C/C composites in simulated body fluid. The SM-DCPD has potential application as the bioactive coatings.

Ammonium, Nitrate, and Phosphate Sorption to and Solute Leaching from Biochars Prepared from Corn Stover ( L.) and Oak Wood ( spp.).

Science.gov (United States)

Hollister, C Colin; Bisogni, James J; Lehmann, Johannes

2013-01-01

Biochar (BC) was evaluated for nitrogen (N) and phosphorus (P) removal from aqueous solution to quantify its nutrient pollution mitigation potential in agroecosystems. Sorption isotherms were prepared for solutions of ammonium (NH), nitrate (NO), and phosphate (PO-P) using BC of corn ( L.) and oak ( spp.) feedstock, each pyrolyzed at 350 and 550°C highest treatment temperature (HTT). Sorption experiments were performed on original BC as well as on BC that went through a water extraction pretreatment (denoted WX-BC). Ammonium sorption was observed for WX-Oak-BC and WX-Corn-BC, and Freundlich model linearization showed that a 200°C increase in HTT resulted in a 55% decrease in * values for WX-Oak-BC and a 69% decrease in * for WX-Corn-BC. Nitrate sorption was not observed for any BC. Removing metals by water extraction from WX-Oak-350 and WX-Oak-550 resulted in a 25 to 100% decrease in phosphate removal efficiency relative to original Oak-350 and Oak-550, respectively. No PO-P sorption was observed using any Corn-BC. Calcium (Ca) leached from BC produced at 550°C was 63 and 104% higher than from BC produced at 350°C for corn and oak, respectively. Leaching of P was two orders of magnitude lower in WX-Oak-BC than in WX-Corn-BC, concurrent with similar difference in magnesium (Mg). Nitrate and NH leaching from consecutive water extractions of all tested BCs was mostly below detection limits. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

The corrosion properties of phosphate coating on AZ31 magnesium alloy: The effect of sodium dodecyl sulfate (SDS) as an eco-friendly accelerating agent

Energy Technology Data Exchange (ETDEWEB)

Amini, R. [Department of Polymer Engineering and Color Technology, AmirKabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Sarabi, A.A., E-mail: sarabi@aut.ac.ir [Department of Polymer Engineering and Color Technology, AmirKabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of)

2011-06-01

Sodium nitrite has been used as an accelerating agent in phosphating bath to improve its properties. However, it is well known that sodium nitrite is a carcinogenic component in phosphating sludge. In this study, it has been aimed to replace sodium nitrite by an environmentally friendly accelerating agent. To this end, sodium dodecyl sulfate (SDS) was used in phosphating bath to improve the phosphate coating formation on an AZ31 magnesium alloy. The effect of SDS/sodium nitrite ratio on the phosphated samples properties was also studied. Using field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), direct current (DC) polarization and electrochemical impedance spectroscopy (EIS) the properties of phosphated magnesium samples were studied. Results showed uniform phosphate coating formation on the magnesium sample mostly in hopeite phase composition. In addition, a denser and less permeable coating can be obtained at these conditions. The corrosion resistance of the phosphated samples was superiorly improved using higher SDS concentration in the phosphating bath.

The corrosion properties of phosphate coating on AZ31 magnesium alloy: The effect of sodium dodecyl sulfate (SDS) as an eco-friendly accelerating agent

International Nuclear Information System (INIS)

Amini, R.; Sarabi, A.A.

2011-01-01

Sodium nitrite has been used as an accelerating agent in phosphating bath to improve its properties. However, it is well known that sodium nitrite is a carcinogenic component in phosphating sludge. In this study, it has been aimed to replace sodium nitrite by an environmentally friendly accelerating agent. To this end, sodium dodecyl sulfate (SDS) was used in phosphating bath to improve the phosphate coating formation on an AZ31 magnesium alloy. The effect of SDS/sodium nitrite ratio on the phosphated samples properties was also studied. Using field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), direct current (DC) polarization and electrochemical impedance spectroscopy (EIS) the properties of phosphated magnesium samples were studied. Results showed uniform phosphate coating formation on the magnesium sample mostly in hopeite phase composition. In addition, a denser and less permeable coating can be obtained at these conditions. The corrosion resistance of the phosphated samples was superiorly improved using higher SDS concentration in the phosphating bath.

Occupational exposures in two industrial plants devoted to the production of ammonium phosphate fertilisers

International Nuclear Information System (INIS)

Bolívar, J P; Mosqueda, F; Gázquez, M J; López-Coto, I; Vaca, F; García-Tenorio, R; Adame, J A

2013-01-01

In order to fill a gap in the open literature, occupational exposures and activity concentrations have been assessed in two NORM industrial plants, located in the south-west of Spain, devoted to the production of mono-ammonium phosphate (MAP) and di-ammonium phosphate (DAP) fertilisers. The annual effective doses received by the workers from these plants are clearly below 1 mSv yr −1 and the contribution due to external radiation is similar to that due to inhalation. The contribution to the maximum effective doses due to inhalation of particulate matter has been estimated to be about 0.12 mSv yr −1 , while the 222 Rn concentrations inside the plants are of no concern. Consequently, no additional actions or radiological protection measures need to be taken to decrease the natural radiation received by the workers in these facilities. (paper)

The effect of adding magnesium oxide on the mechanical properties of the tricalcium phosphate-zirconia composites

Energy Technology Data Exchange (ETDEWEB)

Sallemi, Imen, E-mail: imen.sallemi@hotmail.com; Bouaziz, Jamel; Ben Ayed, Foued

2015-02-01

The effect of magnesium oxide on the mechanical properties of the tricalcium phosphate – 50 wt.% zirconia composites was investigated during a sintering process between 1300 °C and 1400 °C. The characteristics of the samples before and after the sintering process were realized by using the differential thermal analysis, dilatometry, X-ray diffraction, the {sup 31}P magic angle scanning nuclear magnetic resonance, the scanning electron microscope and by considering such mechanical properties as the rupture strength and Vickers hardness. The mechanical performances of the tricalcium phosphate-50 wt.% zirconia composites increased with both the percentage of magnesium oxide and the sintering temperature. At 1400 °C, the mechanical properties of the composites sintered with 10 wt.% magnesium oxide reached their maximum value. Thus, Vickers hardness increased from 554 to 6350 MPa and the rupture strength of the corresponding composites varied from 5.2 to 25 MPa. The increase of the mechanical properties of the samples is due to the formation of both the tetragonal zirconia phase and the liquid phase which helps to fill the pores. The microstructure of needle form is most probably phosphate precipitates which are formed from this liquid phase. Furthermore, the presence of magnesium oxide in the composites prevented the inverse allotropic transformation of zirconia. - Highlights: • We measure the rupture strength and Vickers hardness of bioceramics. • We characterize the effect of MgO on the mechanical properties of the tricalcium phosphate – 50 wt% zirconia composites. • MgO increase the mechanical properties of the composites.

Mechanical, degradation and cytocompatibility properties of magnesium coated phosphate glass fibre reinforced polycaprolactone composites.

Science.gov (United States)

Liu, Xiaoling; Hasan, Muhammad S; Grant, David M; Harper, Lee T; Parsons, Andrew J; Palmer, Graham; Rudd, Chris D; Ahmed, Ifty

2014-11-01

Retention of mechanical properties of phosphate glass fibre reinforced degradable polyesters such as polycaprolactone and polylactic acid in aqueous media has been shown to be strongly influenced by the integrity of the fibre/polymer interface. A previous study utilising 'single fibre' fragmentation tests found that coating with magnesium improved the fibre and matrix interfacial shear strength. Therefore, the aim of this study was to investigate the effects of a magnesium coating on the manufacture and characterisation of a random chopped fibre reinforced polycaprolactone composite. Short chopped strand non-woven phosphate glass fibre mats were sputter coated with degradable magnesium to manufacture phosphate glass fibre/polycaprolactone composites. The degradation behaviour (water uptake, mass loss and pH change of the media) of these polycaprolactone composites as well as of pure polycaprolactone was investigated in phosphate buffered saline. The Mg coated fibre reinforced composites revealed less water uptake and mass loss during degradation compared to the non-coated composites. The cations released were also explored and a lower ion release profile for all three cations investigated (namely Na(+), Mg(2+) and Ca(2+)) was seen for the Mg coated composite samples. An increase of 17% in tensile strength and 47% in tensile modulus was obtained for the Mg coated composite samples. Both flexural and tensile properties were investigated and a higher retention of mechanical properties was obtained for the Mg coated fibre reinforced composite samples up to 10 days immersion in PBS. Cytocompatibility study showed both composite samples (coated and non-coated) had good cytocompatibility with human osteosarcoma cell line. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Synthesis and characterization of the aluminium phosphates modified with ammonium, calcium and molybdenum by hydrothermal method

Directory of Open Access Journals (Sweden)

Łuczka Kinga

2016-06-01

Full Text Available Synthesis and characterization of the aluminum phosphates modified with ammonium, calcium and molybdenum were conducted. The influence of process parameters (reactive pressure and molar ratios in the reaction mixture were studied. The contents of the individual components in the products were in the range of: 10.97–17.31 wt% Al, 2.65–13.32 wt% Ca, 0.70–3.11 wt% Mo, 4.36–8.38 wt% NH3, and 35.12–50.54 wt% P2O5. The materials obtained in the experiments were characterized by various physicochemical parameters. The absorption oil number was in the range from 67 to 89 of oil/100 g of product, the surface area was within the range of 4–76 m2/g, whereas the average particle size of products reached 282–370 nm. The Tafel tests revealed comparable anticorrosive properties of aluminum phosphates modified with ammonium, calcium, molybdenum in comparison with commercial phosphate.

Effect of Oestrogen on Altering the Serum and Urinary Levels of Calcium, Phosphate and Magnesium in Hysterectomised Women Compared to Natural Menopausal South Indian Women: A Case Control Study.

Science.gov (United States)

Sonu, Yeldose; Avinash, S S; Sreekantha; Arun Kumar, K; Malathi, M; Shivashankara, A R

2016-07-01

Given the paucity of studies conducted to know the effect of suddenness and earlier onset of endocrinological changes associated with hysterectomy, on the serum and urinary levels of calcium, magnesium and phosphate the present study was conducted to compare the levels of calcium, magnesium and phosphate in serum and urine of hysterectomised and natural menopausal south Indian women. This is a cross-sectional observational study. The study included three groups of 30 healthy premenopausal, 30 early surgical menopausal and 30 natural post menopausal women. Women suffering from any endocrine disease were excluded. Analysis was performed in serum and urine sample. The levels of calcium, magnesium and phosphate in serum and calcium/creatinine, magnesium/creatinine and phosphate/creatinine ratio were estimated in urine by spectrophotometric method. Hysterectomised women (serum calcium: 8.7 ± 0.09 mg/dl; urine calcium/creatinine: 0.16 ± 0.02) have significantly low serum calcium (p women (serum magnesium: 2.1 ± 0.03; serum phosphate: 4.4 ± 0.16; urinary calcium/creatinine: 0.17 ± 0.02; urinary magnesium/creatinine: 0.09 ± 0.01) have significantly high serum magnesium (p = 0.016), serum phosphate (p = 0.043) and high urinary calcium/creatinine (p = 0.002), magnesium/creatinine ratio (p = 0.025) compared to healthy pre menopausal women. Post menopausal women (serum calcium: 9.1 ± 0.08) have significantly high serum calcium and phosphate compared to hysterectomised women (serum phosphate: 3.93 ± 0.11). Hysterectomised women have significantly low serum calcium, oestrogen and high urinary calcium/creatinine ratio compared to healthy premenopausal women and low serum calcium and low serum phosphate compared to natural postmenopausal women. Natural postmenopausal women had low serum oestrogen and high serum magnesium, serum phosphate, urinary calcium creatinine ratio and urinary magnesium creatinine ratio compared to healthy premenopausal

Magnesium bicarbonate as an in situ uranium lixiviant

International Nuclear Information System (INIS)

Sibert, J.W.

1984-01-01

In the subsurface solution mining of mineral values, especially uranium, in situ, magnesium bicarbonate leaching solution is used instead of sodium, potassium and ammonium carbonate and bicarbonates. The magnesium bicarbonate solution is formed by combining carbon dioxide with magnesium oxide and water. The magnesium bicarbonate lixivant has four major advantages over prior art sodium, potassium and ammonium bicarbonates

A statistical investigation of the rheological properties of magnesium phosphate cement

OpenAIRE

Yue, Y.; Bai, Y.; Hu, W.; You, C.; Qian, J.; McCague, C.; Jin, F.; Al-Tabbaa, A.; Mo, L.; Deng, M.

2016-01-01

Magnesium phosphate cement (MPC) is a promising material applied for rapid patch repairing in civil engineering and waste immobilisation in nuclear industry. However, the rheological properties of this new binder material which highly affects its engineering application, is to be explored. The current work aims at investigating the rheological properties of MPC along 98 with determining the optimum conditions to obtain MPC materials with desirable rheological performances. ...

Application of l-ascorbic acid and its derivatives (sodium ascorbyl phosphate and magnesium ascorbyl phosphate) in topical cosmetic formulations: stability studies

International Nuclear Information System (INIS)

Smaoui, S.; Hilima, H.B.

2013-01-01

The present study aimed to formulate and subsequently evaluate a topical skin-care cream (o/w emulsion) from l-ascorbic acid and its derivatives (sodium ascorbyl phosphate and magnesium ascorbyl phosphate) at 2% versus its vehicle (Control). Formulations were developed by entrapping it in the oily phase of o/w emulsion and were stored at 8 degree C, 25 degree C and 40 degree C (in incubator) for a period of four weeks to investigate their stability. In the physical analysis, the evaluation parameters consisted of color, smell, phase separation, centrifugation, and liquefaction. Chemical stability of both derivatives was established by HPLC analysis. In the chemical analysis, the formulation with sodium ascorbyl phosphate was more stable than those with magnesium ascorbyl phosphate and l-ascorbic acid. The microbiological stability of the formulations was also evaluated. The findings indicated that the formulations with l-ascorbic acid and its derivatives were efficient against the proliferation of various spoilage microorganisms, including aerobic plate counts as well as Pseudomonas aeruginosa, Staphylococcus aureus, and yeast and mold counts. The results presented in this work showed good stability throughout the experimental period. Newly formulated emulsion proved to exhibit a number of promising properties and attributes that might open new opportunities for the construction of more efficient, safe, and cost-effective skin-care, cosmetic, and pharmaceutical products. (author)

Corrosion resistance of biomimetic calcium phosphate coatings on magnesium due to varying pretreatment time

Energy Technology Data Exchange (ETDEWEB)

Waterman, J., E-mail: jay.waterman@pg.canterbury.ac.nz [Department of Mechanical Engineering, University of Canterbury, Christchurch (New Zealand); Pietak, A. [Department of Anatomy and Structural Biology, University of Otago, Dunedin (New Zealand); Birbilis, N. [Department of Materials Engineering, Monash University (Australia); Woodfield, T. [Department of Mechanical Engineering, University of Canterbury, Christchurch (New Zealand); Department of Orthopaedic Surgery, University of Otago, Christchurch (New Zealand); Dias, G. [Department of Anatomy and Structural Biology, University of Otago, Dunedin (New Zealand); Staiger, M.P., E-mail: mark.staiger@canterbury.ac.nz [Department of Mechanical Engineering, University of Canterbury, Christchurch (New Zealand)

2011-12-15

Calcium phosphate coatings were prepared on magnesium substrates via a biomimetic coating process. The effects of a magnesium hydroxide pretreatment on the formation and the ultimate corrosion protection of the coatings were studied. The pretreatment layer was found to affect the amount of defects present in the coatings. Corrosion resistance of the coatings was studied in vitro using two simulated body fluids, 0.8% NaCl and Hanks solution. In NaCl, the resistance to corrosion of all samples decreases with time as corrosion proceeded through cracks and other defects in the coatings. Samples with no pretreatment displayed the highest corrosion resistance as these samples had the fewest defects in the coating. However, in Hanks solution, corrosion resistance increased with time due to additional nucleation of calcium phosphate from the fluid on to the substrate. In this solution, additional pretreatment time was beneficial to the overall corrosion resistance.

Mg-doped biphasic calcium phosphate by a solid state reaction route: Characterization and evaluation of cytotoxicity

Energy Technology Data Exchange (ETDEWEB)

Webler, Geovana D. [Instituto de Física, Universidade Federal de Alagoas, Maceió-AL 57072970 (Brazil); Correia, Ana C.C.; Barreto, Emiliano [Laboratório de Biologia Celular, Universidade Federal de Alagoas, Maceió-AL 57072970 (Brazil); Fonseca, Eduardo J.S., E-mail: eduardo@fis.ufal.br [Instituto de Física, Universidade Federal de Alagoas, Maceió-AL 57072970 (Brazil)

2015-07-15

Hydroxyapatite (HAP) and β-tricalcium phosphate (β-TCP) are widely used in tissue engineering because of their chemical similarity to the inorganic bone phase. In this work, we prepare biphasic calcium phosphate (BCP, a mixture of HAP and β-TCP) doped with different concentrations of magnesium to investigate the influence of magnesium on the BCP crystal structure. Magnesium is known to be an important element in the composition of bones and teeth. Recent research has shown that the doping of magnesium into BCP improves its bone metabolism and mechanical properties without affecting its biocompatibility. The samples were prepared by solid-state reaction from calcium carbonate, monobasic ammonium phosphate, and magnesium nitrate hexahydrate. Varying concentrations of magnesium were used and its modifications were examined by different characterization techniques. The phase composition and morphology of the ceramic powders were characterized by X-ray diffraction and scanning electron microscopy, respectively. The functional groups were analyzed using Fourier transform infrared spectroscopy and Raman spectroscopy. Cell viability experiments, using macrophage-like cell lines J774, showed that the synthesized Mg-doped BCP did not exhibit cytotoxicity regardless of the doses assayed or the different concentrations of magnesium used, suggesting it as a good material for potential biological applications. - Highlights: • Simple and fast method for the preparation of the Mg-BCP. • Study of the influence of the incorporation of Mg in the BCP. • Cell viability showed that the synthesized Mg-BCP did not exhibit cytotoxicity.

Mg-doped biphasic calcium phosphate by a solid state reaction route: Characterization and evaluation of cytotoxicity

International Nuclear Information System (INIS)

Webler, Geovana D.; Correia, Ana C.C.; Barreto, Emiliano; Fonseca, Eduardo J.S.

2015-01-01

Hydroxyapatite (HAP) and β-tricalcium phosphate (β-TCP) are widely used in tissue engineering because of their chemical similarity to the inorganic bone phase. In this work, we prepare biphasic calcium phosphate (BCP, a mixture of HAP and β-TCP) doped with different concentrations of magnesium to investigate the influence of magnesium on the BCP crystal structure. Magnesium is known to be an important element in the composition of bones and teeth. Recent research has shown that the doping of magnesium into BCP improves its bone metabolism and mechanical properties without affecting its biocompatibility. The samples were prepared by solid-state reaction from calcium carbonate, monobasic ammonium phosphate, and magnesium nitrate hexahydrate. Varying concentrations of magnesium were used and its modifications were examined by different characterization techniques. The phase composition and morphology of the ceramic powders were characterized by X-ray diffraction and scanning electron microscopy, respectively. The functional groups were analyzed using Fourier transform infrared spectroscopy and Raman spectroscopy. Cell viability experiments, using macrophage-like cell lines J774, showed that the synthesized Mg-doped BCP did not exhibit cytotoxicity regardless of the doses assayed or the different concentrations of magnesium used, suggesting it as a good material for potential biological applications. - Highlights: • Simple and fast method for the preparation of the Mg-BCP. • Study of the influence of the incorporation of Mg in the BCP. • Cell viability showed that the synthesized Mg-BCP did not exhibit cytotoxicity

Radio phosphorus kinetics in the blood of sheep supplemented with dicalcium phosphate, mono ammonium phosphate, triple superphosphate and Tapira rock phosphate

International Nuclear Information System (INIS)

Abdalla, A.L.

1992-01-01

With the aim to study the kinetics of radio phosphorus ( 32 P) in the blood of animals supplemented with dicalcium phosphate (BIC), mono ammonium phosphate (MAP), triple superphosphate (SPT) and Tapira rock phosphate (TAP), 32 male sheep were kept in metabolic cages at the Animal Science Section / CENA - USP. Plasma was obtained by centrifugation and the specific activity, rate of disappearance and half life of 32 P in plasma were determined. In the red blood cells were determined the uptake rate of the radioisotope, the rate of disappearance and half life of 32 P up taken. It was observed a statistical significant difference (p 32 P in the plasma and erythrocytes. The specific activity and half life of 32 P in the plasma were statistically different (p<0,10) among sheep receiving the different phosphorus sources; the same was observed in respect to the red blood cells. It was concluded that the supplemented phosphorus source given in the diet of sheep may affect the kinetics of the radio phosphorus in the blood after been intravenously injected. (author)

Reaction Mechanisms of Magnesium Potassium Phosphate Cement and its Application

Science.gov (United States)

Qiao, Fei

Magnesium potassium phosphate cement (MKPC) is a kind of cementitious binder in which the chemical bond is formed via a heterogeneous acid-base reaction between dead burned magnesia powder and potassium phosphate solution at room temperature. Small amount of boron compounds can be incorporated in the cement as a setting retarder. The final reaction product of MgO-KH2PO4-H 2O ternary system is identified as magnesium potassium phosphate hexahydrate, MgKPO4·6H2O. However, the mechanisms and procedures through which this crystalline product is formed and the conditions under which the crystallization process would be influenced are not yet clear. Understanding of the reaction mechanism of the system is helpful for developing new methodologies to control the rapid reaction process and furthermore, to adjust the phase assemblage of the binder, and to enhance the macroscopic properties. This study is mainly focused on the examination of the reaction mechanism of MKPC. In addition, the formulation optimization, microstructure characterization and field application in rapid repair are also systematically studied. The chemical reactions between magnesia and potassium dihydrogen phosphate are essentially an acid-base reaction with strong heat release, the pH and temperature variation throughout the reaction process could provide useful information to disclose the different stages in the reaction. However, it would be very difficult to conduct such tests on the cement paste due to the limited water content and fast setting. In the current research, the reaction mechanism of MKPC is investigated on the diluted MKPC system through monitoring the pH and temperature development, identification of the solid phase formed, and measurement of the ionic concentration of the solution. The reaction process can be explained as follows: when magnesia and potassium phosphate powder are mixed with water, phosphate is readily dissolved, which is instantly followed by the dissociation of

Performance of phosphogypsum and calcium magnesium phosphate fertilizer for nitrogen conservation in pig manure composting.

Science.gov (United States)

Li, Yun; Luo, Wenhai; Li, Guoxue; Wang, Kun; Gong, Xiaoyan

2018-02-01

This study investigated the performance of phosphogypsum and calcium magnesium phosphate fertilizer for nitrogen conservation during pig manure composting with cornstalk as the bulking agent. Results show that phosphogypsum increased nitrous oxide (N 2 O) emission, but significantly reduced ammonia (NH 3 ) emission and thus enhanced the mineral and total nitrogen (TN) contents in compost. Although N 2 O emission could be reduced by adding calcium magnesium phosphate fertilizer, NH 3 emission was considerably increased, resulting in an increase in TN loss during composting. By blending these two additives, both NH 3 and N 2 O emissions could be mitigated, achieving effective nitrogen conservation in composting. More importantly, with the addition of 20% TN of the mixed composting materials, these two additives could synergistically improve the compost maturity and quality. Copyright © 2017 Elsevier Ltd. All rights reserved.

Degradation processes of reinforced concretes by combined sulfate–phosphate attack

Energy Technology Data Exchange (ETDEWEB)

Secco, Michele, E-mail: michele.secco@unipd.it [Inter-Departmental Research Center for the Study of Cement Materials and Hydraulic Binders (CIRCe), University of Padova, Via Gradenigo 6, 35131 Padova (Italy); Department of Civil, Environmental and Architectural Engineering (ICEA), University of Padova, Via Marzolo 9, 35131 Padova (Italy); Lampronti, Giulio Isacco, E-mail: gil21@cam.ac.uk [Department of Earth Sciences, University of Cambridge, Downing Street, CB2 3EQ Cambridge (United Kingdom); Schlegel, Moritz-Caspar, E-mail: moritz-caspar.schlegel@helmholtz-berlin.de [BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205 Berlin (Germany); Helmholtz-Zentrum Berlin fürMaterialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Maritan, Lara, E-mail: lara.maritan@unipd.it [Department of Geosciences, University of Padova, Via Gradenigo 6, 35131 Padova (Italy); Zorzi, Federico, E-mail: federico.zorzi@unipd.it [Department of Geosciences, University of Padova, Via Gradenigo 6, 35131 Padova (Italy)

2015-02-15

A novel form of alteration due to the interaction between hydrated cement phases and sulfate and phosphate-based pollutants is described, through the characterization of concrete samples from an industrial reinforced concrete building. Decalcification of the cement matrices was observed, with secondary sulfate and phosphate-based mineral formation, according to a marked mineralogical and textural zoning. Five alteration layers may be detected: the two outermost layers are characterized by the presence of gypsum–brushite solid solution phases associated with anhydrous calcium sulfates and phosphates, respectively, while a progressive increase in apatite and ammonium magnesium phosphates is observable in the three innermost layers, associated with specific apatite precursors (brushite, octacalcium phosphate and amorphous calcium phosphate, respectively). The heterogeneous microstructural development of secondary phases is related to the chemical, pH and thermal gradients in the attacked cementitious systems, caused by different sources of pollutants and the exposure to the sun's radiation.

Degradation processes of reinforced concretes by combined sulfate–phosphate attack

International Nuclear Information System (INIS)

Secco, Michele; Lampronti, Giulio Isacco; Schlegel, Moritz-Caspar; Maritan, Lara; Zorzi, Federico

2015-01-01

A novel form of alteration due to the interaction between hydrated cement phases and sulfate and phosphate-based pollutants is described, through the characterization of concrete samples from an industrial reinforced concrete building. Decalcification of the cement matrices was observed, with secondary sulfate and phosphate-based mineral formation, according to a marked mineralogical and textural zoning. Five alteration layers may be detected: the two outermost layers are characterized by the presence of gypsum–brushite solid solution phases associated with anhydrous calcium sulfates and phosphates, respectively, while a progressive increase in apatite and ammonium magnesium phosphates is observable in the three innermost layers, associated with specific apatite precursors (brushite, octacalcium phosphate and amorphous calcium phosphate, respectively). The heterogeneous microstructural development of secondary phases is related to the chemical, pH and thermal gradients in the attacked cementitious systems, caused by different sources of pollutants and the exposure to the sun's radiation

Microwave assisted synthesis and characterization of magnesium substituted calcium phosphate bioceramics

Energy Technology Data Exchange (ETDEWEB)

Khan, Nida Iqbal [Interdisciplinary Research Centre in Biomedical Materials, COMSATS Institute of Information Technology, M. A. Jinnah Campus, Defence Road, Off Raiwind Road, Lahore (Pakistan); Medical Implant Technology Group (MEDITEG), Faculty of Bioscience and Medical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim (Malaysia); Ijaz, Kashif; Zahid, Muniza; Khan, Abdul S. [Interdisciplinary Research Centre in Biomedical Materials, COMSATS Institute of Information Technology, M. A. Jinnah Campus, Defence Road, Off Raiwind Road, Lahore (Pakistan); Abdul Kadir, Mohammed Rafiq [Medical Implant Technology Group (MEDITEG), Faculty of Bioscience and Medical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim (Malaysia); Hussain, Rafaqat [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Skudai, Johore (Malaysia); Anis-ur-Rehman [Department of Physics, COMSATS Institute of Information Technology, Chakshahzad Campus, Islamabad (Pakistan); Darr, Jawwad A. [Clean Materials Technology Group, Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London WC1H 0AJ (United Kingdom); Ihtesham-ur-Rehman [The Kroto Research Institute, North Campus, University of Sheffield, Broad Lane, Sheffield S3 7HQ (United Kingdom); Chaudhry, Aqif A., E-mail: aqifanwar@ciitlahore.edu.pk [Interdisciplinary Research Centre in Biomedical Materials, COMSATS Institute of Information Technology, M. A. Jinnah Campus, Defence Road, Off Raiwind Road, Lahore (Pakistan)

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 1 h) reduced twelve folds (to 2 h) 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 (1 h) at 900 °C. - Highlights: • Microwave irradiation of suspensions of calcium phosphates accelerated maturation. • Reactions took 2 h to complete as compared to 18 h required traditionally. • Magnesium contents higher than 1 wt.% lead to the presence of non-apatitic phases. • Agglomerates with micron and sub-micron porosity were obtained after heat-treatment.

Reduced toxicological activity of cigarette smoke by the addition of ammonium magnesium phosphate to the paper of an electrically heated cigarette: smoke chemistry and in vitro cytotoxicity and genotoxicity.

Science.gov (United States)

Roemer, E; Stabbert, R; Veltel, D; Müller, B P; Meisgen, T J; Schramke, H; Anskeit, E; Elves, R G; Fournier, J A

2008-04-01

The effects of the addition of ammonium magnesium phosphate (AMP) to the paper of an electrically heated cigarette (EHC) prototype on smoke composition and toxicity were quantified and the underlying mechanisms investigated. Smoke from EHC prototypes with and without AMP and from conventional cigarettes, i.e. the University of Kentucky Standard Reference Cigarette 1R4F and eight American-blend market cigarettes, was compared. Endpoints for comparison were smoke chemistry, where toxic constituents were measured, cytotoxic activity, as measured in murine fibroblasts embryo cells by the Neutral Red Uptake Assay, and genotoxic activity, as measured in bacteria by the Salmonella Reverse Mutation Assay and in murine lymphoma cells by the TK Assay. The addition of AMP to the EHC led to a reduction of toxic substances and toxicological activity of approximately 30% compared to the EHC without AMP. Compared to the conventional cigarettes, the EHC with AMP showed reductions of 75-90%. Smoke from the EHCs generated in nitrogen atmospheres supplemented with different concentrations of ammonia and oxygen was assayed for its in vitro cytotoxicity and genotoxicity. The results indicate that the ammonia released by AMP at the heating site of the EHC is responsible for the reductions in cytotoxicity and mutagenicity for the EHC with AMP compared with the EHC without AMP. Thus, while the EHC approach distinctly reduces toxic smoke constituents compared to conventional cigarettes, the use of AMP in the paper of an EHC leads to further distinct reductions. In the study presented here, in vitro assays were used as quantitative tools to investigate toxicity-related mechanisms.

Investigation of the setting reaction in magnesium phosphate ceramics with quasielastic neutron scattering

Czech Academy of Sciences Publication Activity Database

Viani, Alberto; Zbiri, M.; Bordallo, H. N.; Gualtieri, A. F.; Mácová, Petra

2017-01-01

Roč. 121, č. 21 (2017), s. 11355-11367 ISSN 1932-7447 R&D Projects: GA MŠk(CZ) LO1219 Keywords : magnesium potassium phosphate ceramics * amorphous materials * NMR-spectroscopy Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass OBOR OECD: Ceramics Impact factor: 4.536, year: 2016 http://pubs.acs.org/doi/abs/10.1021/acs.jpcc.7b01396

DNA-encapsulated magnesium phosphate nanoparticles elicit both humoral and cellular immune responses in mice

Directory of Open Access Journals (Sweden)

Gajadhar Bhakta

2014-01-01

Full Text Available The efficacy of pEGFP (plasmid expressing enhanced green fluorescent protein-encapsulated PEGylated (meaning polyethylene glycol coated magnesium phosphate nanoparticles (referred to as MgPi-pEGFP nanoparticles for the induction of immune responses was investigated in a mouse model. MgPi-pEGFP nanoparticles induced enhanced serum antibody and antigen-specific T-lymphocyte responses, as well as increased IFN-γ and IL-12 levels compared to naked pEGFP when administered via intravenous, intraperitoneal or intramuscular routes. A significant macrophage response, both in size and activity, was also observed when mice were immunized with the nanoparticle formulation. The response was highly specific for the antigen, as the increase in interaction between macrophages and lymphocytes as well as lymphocyte proliferation took place only when they were re-stimulated with recombinant green fluorescence protein (rGFP. Thus the nanoparticle formulation elicited both humoral as well as cellular responses. Cytokine profiling revealed the induction of Th-1 type responses. The results suggest DNA-encapsulated magnesium phosphate (MgPi nanoparticles may constitute a safer, more stable and cost-efficient DNA vaccine formulation.

Dental plaque microcosm biofilm behavior on calcium phosphate nanocomposite with quaternary ammonium.

Science.gov (United States)

Cheng, Lei; Weir, Michael D; Zhang, Ke; Wu, Eric J; Xu, Sarah M; Zhou, Xuedong; Xu, Hockin H K

2012-08-01

Half of dental restorations fail in 10 years, with secondary caries as the main reason. Calcium phosphate composites could remineralize tooth lesions. The objectives of this study were to: (1) impart antibacterial activity to a composite with nanoparticles of amorphous calcium phosphate (NACP); and (2) investigate the effect of quaternary ammonium dimethacrylate (QADM) on mechanical and dental plaque microcosm biofilm properties for the first time. The NACP and glass particles were filled into a dental resin that contained bis(2-methacryloyloxy-ethyl) dimethyl-ammonium bromide, the QADM. NACP nanocomposites containing 0%, 7%, 14%, and 17.5% of QADM by mass, respectively, were photo-cured. A commercial composite with no antibacterial activity was used as control. Mechanical properties were measured in three-point flexure. A human saliva microcosm model was used to grow biofilms on composites. Live/dead assay, metabolic activity, colony-forming unit (CFU) counts, and lactic acid production of biofilms on the composites were measured. Increasing QADM mass fraction monotonically reduced the biofilm viability, CFU and lactic acid. Biofilms on NACP nanocomposite with 17.5% QADM had metabolic activity that was 30% that on a commercial composite control (pbacterial cells with normal short-rod shapes, while some cells on NACP-QADM nanocomposites disintegrated into pieces. Adding QADM to NACP did not decrease the composite strength and elastic modulus, which matched (p>0.1) those of a commercial composite without Ca-PO(4) or antibacterial activity. A dental plaque microcosm model was used to evaluate the novel NACP-QADM nanocomposite. The nanocomposite greatly reduced the biofilm viability, metabolic activity and lactic acid, while its mechanical properties matched those of a commercial composite. NACP-QADM nanocomposite with calcium phosphate fillers, good mechanical properties and a strong antibacterial activity may have potential for anti-biofilm and anti

Investigation of setting reaction in magnesium potassium phosphate ceramics with time resolved infrared spectroscopy

Czech Academy of Sciences Publication Activity Database

Mácová, Petra; Viani, Alberto

2017-01-01

Roč. 205, October (2017), s. 62-66 ISSN 0167-577X R&D Projects: GA MŠk(CZ) LO1219 Keywords : amorphous materials * magnesium potassium phosphate cements * FTIR Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass OBOR OECD: Ceramics Impact factor: 2.572, year: 2016 http://www.sciencedirect.com/science/article/pii/S0167577X17309552

Structural and thermochemical properties of sodium magnesium phosphate glasses

Energy Technology Data Exchange (ETDEWEB)

Oueslati Omrani, Refka [Université de Tunis El Manar, Faculté des Sciences de Tunis, Chemistry Department, LR01SE10 Applied Thermodynamics Laboratory, 2092 Tunis (Tunisia); Kaoutar, Abdeltif; El Jazouli, Abdelaziz [LCMS, URAC 17, Faculté des Sciences Ben M’Sik, UH2MC, Casablanca (Morocco); Krimi, Saida [LPCMI, Faculté des Sciences Aïn Chok, UH2C, Casablanca (Morocco); Khattech, Ismail, E-mail: ismail.khattech@fst.rnu.tn [Université de Tunis El Manar, Faculté des Sciences de Tunis, Chemistry Department, LR01SE10 Applied Thermodynamics Laboratory, 2092 Tunis (Tunisia); Jemal, Mohamed [Université de Tunis El Manar, Faculté des Sciences de Tunis, Chemistry Department, LR01SE10 Applied Thermodynamics Laboratory, 2092 Tunis (Tunisia); Videau, Jean-Jacques [ICMCB, Institut de Chimie de la matière condensée, Université de Bordeaux 1 (France); Couzi, Michel [Institut des Sciences Moléculaires, CNRS-Université de Bordeaux 1 (France)

2015-05-25

Highlights: • Phosphate glasses were prepared by met quenching technique. • Structural study is investigated using FTIR, Raman and {sup 31}PNMR spectroscopy. • A 4.5% weight of H{sub 3}PO{sub 4} solution has use for glass dissolution. • Dissolution is endothermic for lower MgO content and becomes exothermic when x rises. - Abstract: Ternary phosphate based glasses with the general formula (50−x/2)Na{sub 2}O–xMgO–(50−x/2)P{sub 2}O{sub 5} (0 ⩽ x ⩽ 42.8 mol%), where the O/P ratio was varied from 3 to 3.75, have been prepared using a conventional melt quenching technique. Samples were investigated by means of density measurements, Fourier-transformed infrared (FTIR), Raman and {sup 31}P solid state magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopies, differential scanning calorimetry (DSC), inductively coupled plasma atomic emission spectroscopy (ICP/AES) analysis and calorimetric dissolution. The depolymerization of metaphosphate chains are described by the decrease of Q{sup 2} tetrahedral sites allowing the formation of pyrophosphate groups (Q{sup 1}) revealed by spectroscopic investigations. As a result, the increase of density and glass transition temperature when x rises. Calorimetric study shows that the dissolution phenomenon is endothermic for a lower MgO content and becomes exothermic when magnesium oxide is gradually incorporated, suggesting the disruption of phosphate chains with increasing O/P ratio.

Evaluation of ammonium nitrate phosphate (Suphala) having different water soluble phosphorus levels on black soils

International Nuclear Information System (INIS)

Deo Dutt; Mutatkar, V.K.; Chapke, V.G.

1974-01-01

Efficiency of the laboratory prepared 32 P tagged ammonium nitrate phosphate (Suphala) varying in water soluble P was studied both on calcareous and non-calcareous soils of Maharashtra for bajra and wheat crops under greenhouse conditions. The results revealed a significant increase in dry matter production and uptake of total and fertilizer P with Suphala containing 30-32% water-soluble phosphorus. (author)

Magnesium Coated Bioresorbable Phosphate Glass Fibres: Investigation of the Interface between Fibre and Polyester Matrices

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Xiaoling Liu

2013-01-01

Full Text Available Bioresorbable phosphate glass fibre reinforced polyester composites have been investigated as replacement for some traditional metallic orthopaedic implants, such as bone fracture fixation plates. However, composites tested revealed loss of the interfacial integrity after immersion within aqueous media which resulted in rapid loss of mechanical properties. Physical modification of fibres to change fibre surface morphology has been shown to be an effective method to improve fibre and matrix adhesion in composites. In this study, biodegradable magnesium which would gradually degrade to Mg2+ in the human body was deposited via magnetron sputtering onto bioresorbable phosphate glass fibres to obtain roughened fibre surfaces. Fibre surface morphology after coating was observed using scanning electron microscope (SEM. The roughness profile and crystalline texture of the coatings were determined via atomic force microscope (AFM and X-ray diffraction (XRD analysis, respectively. The roughness of the coatings was seen to increase from 40±1 nm to 80±1 nm. The mechanical properties (tensile strength and modulus of fibre with coatings decreased with increased magnesium coating thickness.

Hierarchical one-dimensional ammonium nickel phosphate microrods for high-performance pseudocapacitors

CSIR Research Space (South Africa)

Raju, K

2015-12-01

Full Text Available :17629 | DOI: 10.1038/srep17629 www.nature.com/scientificreports Hierarchical One-Dimensional Ammonium Nickel Phosphate Microrods for High-Performance Pseudocapacitors Kumar Raju1 & Kenneth I. Ozoemena1,2 High-performance electrochemical capacitors... OPEN w w w . n a t u r e . c o m / s c i e n t i f i c r e p o r t s / 2S C I E N T I F I C REPORTS | 5:17629 | DOI: 10.1038/srep17629 Hierarchical 1-D and 2-D materials maximize the supercapacitive properties due to their unique ability to permit ion...

Ammonium iron(III phosphate(V fluoride, (NH40.5[(NH40.375K0.125]FePO4F, with ammonium partially substituted by potassium

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Lei Wang

2009-01-01

Full Text Available The title compound, ammonium potassium iron(III phosphate fluoride, (NH40.875K0.125FePO4F, is built from zigzag chains ∞1{[FeO4F2]7−}, with Fe3+ in a distorted octahedral coordination, extending along both the [011] and [0overline{1}1] directions. These chains are made up of alternating trans-[FeO4F2] and cis-[FeO4F2] octahedra via shared F-atom corners, and are linked by PO4 tetrahedra, resulting in an open-framework structure with channels along the [010] and [100] directions. There are two crystallographically independent ammonium sites: one in the [010] channels and the other, partially substituted by K+ ions, in the [100] channels. The ammonium in the [010] channels is fixed to the framework via eight hydrogen bonds (six N—H...O and two N—H...F.

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

Science.gov (United States)

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

2015-01-01

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. 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. 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. 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.

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

Directory of Open Access Journals (Sweden)

K S Rajesh

2015-01-01

Full Text Available 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.

Microwave assisted preparation of magnesium phosphate cement (MPC) for orthopedic applications: A novel solution to the exothermicity problem

International Nuclear Information System (INIS)

Zhou, Huan; Agarwal, Anand K.; Goel, Vijay K.; Bhaduri, Sarit B.

2013-01-01

There are two interesting features of this paper. First, we report herein a novel microwave assisted technique to prepare phosphate based orthopedic cements, which do not generate any exothermicity during setting. The exothermic reactions during the setting of phosphate cements can cause tissue damage during the administration of injectable compositions and hence a solution to the problem is sought via microwave processing. This solution through microwave exposure is based on a phenomenon that microwave irradiation can remove all water molecules from the alkaline earth phosphate cement paste to temporarily stop the setting reaction while preserving the active precursor phase in the formulation. The setting reaction can be initiated a second time by adding aqueous medium, but without any exothermicity. Second, a special emphasis is placed on using this technique to synthesize magnesium phosphate cements for orthopedic applications with their enhanced mechanical properties and possible uses as drug and protein delivery vehicles. The as-synthesized cements were evaluated for the occurrences of exothermic reactions, setting times, presence of Mg-phosphate phases, compressive strength levels, microstructural features before and after soaking in (simulated body fluid) SBF, and in vitro cytocompatibility responses. The major results show that exposure to microwaves solves the exothermicity problem, while simultaneously improving the mechanical performance of hardened cements and reducing the setting times. As expected, the cements are also found to be cytocompatible. Finally, it is observed that this process can be applied to calcium phosphate cements system (CPCs) as well. Based on the results, this microwave exposure provides a novel technique for the processing of injectable phosphate bone cement compositions. - Highlights: • A microwave assisted system for bone cement manufacturing • A solution to exothermicity problem of acid–base reaction based bone cement �

Microwave assisted preparation of magnesium phosphate cement (MPC) for orthopedic applications: A novel solution to the exothermicity problem

Energy Technology Data Exchange (ETDEWEB)

Zhou, Huan, E-mail: Huan.Zhou@rockets.utoledo.edu [Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH 43606 (United States); Agarwal, Anand K.; Goel, Vijay K. [Department of Bioengineering, The University of Toledo, Toledo, OH 43606 (United States); Bhaduri, Sarit B. [Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH 43606 (United States); Division of Dentistry, The University of Toledo, Toledo, OH 43606 (United States)

2013-10-15

There are two interesting features of this paper. First, we report herein a novel microwave assisted technique to prepare phosphate based orthopedic cements, which do not generate any exothermicity during setting. The exothermic reactions during the setting of phosphate cements can cause tissue damage during the administration of injectable compositions and hence a solution to the problem is sought via microwave processing. This solution through microwave exposure is based on a phenomenon that microwave irradiation can remove all water molecules from the alkaline earth phosphate cement paste to temporarily stop the setting reaction while preserving the active precursor phase in the formulation. The setting reaction can be initiated a second time by adding aqueous medium, but without any exothermicity. Second, a special emphasis is placed on using this technique to synthesize magnesium phosphate cements for orthopedic applications with their enhanced mechanical properties and possible uses as drug and protein delivery vehicles. The as-synthesized cements were evaluated for the occurrences of exothermic reactions, setting times, presence of Mg-phosphate phases, compressive strength levels, microstructural features before and after soaking in (simulated body fluid) SBF, and in vitro cytocompatibility responses. The major results show that exposure to microwaves solves the exothermicity problem, while simultaneously improving the mechanical performance of hardened cements and reducing the setting times. As expected, the cements are also found to be cytocompatible. Finally, it is observed that this process can be applied to calcium phosphate cements system (CPCs) as well. Based on the results, this microwave exposure provides a novel technique for the processing of injectable phosphate bone cement compositions. - Highlights: • A microwave assisted system for bone cement manufacturing • A solution to exothermicity problem of acid–base reaction based bone cement �

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

OpenAIRE

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

2015-01-01

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 usin...

Cesium immobilization into potassium magnesium phosphate matrix

International Nuclear Information System (INIS)

Sayenko, S.Y.; Shkuropatenko, V.A.; Bereznyak, O.P.; Hodyreva, Y.S.; Tarasov, R.V.; Virych, V.D.; Ulybkina, E.A.; Pylypenko, O.V.; Kholomeev, G.O.; Zykova, A.V.; Wagh, Arun S.

2017-01-01

The possibility of isomorphous substitution of potassium ions by cesium ions in the structure of potassium magnesium phosphate KMgPO 4 centred dot 6H 2 O (PMP) was shown. It was established, that the Cs included into the PMP matrix does not transfer to the environment during high temperatures heating process (1176 deg C, 3 hours). Analysis of the IR absorption spectrum of the PMP sample has demonstrated that an increase in the amount of additive of the cesium chloride resulted in the shift of the main bands in the spectrum to the low-frequency region with average shift value 10 cm -1 , which indicates the strengthening of bonds in the crystal lattice of matter. The calculated degree of substitution of potassium by cesium during energy release process in the PMP matrix at the level of vitrified high level wastes is about 4%, i. e. the PMP matrix should correspond to the formula K 0.96 Cs 0.04 MgPO 4 centred dot 6H 2 O.

Detection of innersphere interactions between magnesium hydrate and the phosphate backbone of the HDV ribozyme using Raman crystallography.

Science.gov (United States)

Gong, Bo; Chen, Yuanyuan; Christian, Eric L; Chen, Jui-Hui; Chase, Elaine; Chadalavada, Durga M; Yajima, Rieko; Golden, Barbara L; Bevilacqua, Philip C; Carey, Paul R

2008-07-30

A Raman microscope and Raman difference spectroscopy are used to detect the vibrational signature of RNA-bound magnesium hydrate in crystals of hepatitis delta virus (HDV) ribozyme and to follow the effects of magnesium hydrate binding to the nonbridging phosphate oxygens in the phosphodiester backbone. There is a correlation between the Raman intensity of the innersphere magnesium hydrate signature peak, near 322 cm-1, and the intensity of the PO2- symmetric stretch, near 1100 cm-1, perturbed by magnesium binding, demonstrating direct observation of -PO2-...Mg2+(H2O)x innersphere complexes. The complexes may be pentahydrates (x = 5) and tetrahydrates (x = 4). The assignment of the Raman feature near 322 cm-1 to a magnesium hydrate species is confirmed by isotope shifts observed in D2O and H218O that are semiquantitatively reproduced by calculations. The standardized intensity changes in the 1100 cm-1 PO2- feature seen upon magnesium hydrate binding indicates that there are approximately 5 innersphere Mg2+...-O2P contacts per HDV molecule when the crystal is exposed to a solution containing 20 mM magnesium.

Effect of raw material ratios on the compressive strength of magnesium potassium phosphate chemically bonded ceramics

International Nuclear Information System (INIS)

Wang, Ai-juan; Yuan, Zhi-long; Zhang, Jiao; Liu, Lin-tao; Li, Jun-ming; Liu, Zheng

2013-01-01

The compressive strength of magnesium potassium phosphate chemically bonded ceramics is important in biomedical field. In this work, the compressive strength of magnesium potassium phosphate chemically bonded ceramics was investigated with different liquid-to-solid and MgO-to-KH 2 PO 4 ratios. X-ray diffractometer was applied to characterize its phase composition. The microstructure was imaged using a scanning electron microscope. The results showed that the compressive strength of the chemically bonded ceramics increased with the decrease of liquid-to-solid ratio due to the change of the packing density and the crystallinity of hydrated product. However, with the increase of MgO-to-KH 2 PO 4 weight ratio, its compressive strength increased firstly and then decreased. The low compressive strength in lower MgO-to-KH 2 PO 4 ratio might be explained by the existence of the weak phase KH 2 PO 4 . However, the low value of compressive strength with the higher MgO-to-KH 2 PO 4 ratio might be caused by lack of the joined phase in the hydrated product. Besides, it has been found that the microstructures were different in these two cases by the scanning electron microscope. Colloidal structure appeared for the samples with lower liquid-to-solid and higher MgO-to-KH 2 PO 4 ratios possibly because of the existence of amorphous hydrated products. The optimization of both liquid-to-solid and MgO-to-KH 2 PO 4 ratios was important to improve the compressive strength of magnesium potassium phosphate chemically bonded ceramics. - Highlights: • High packing density and amorphous hydrated phase improved the compressive strength. • Residual KH 2 PO 4 and poor bonding phase lower the compressive strength. • MPCBC fabricated with optimized parameters had the highest compressive strength

Effect of L-Ascorbyl-2-Phosphate Magnesium as a Vitamin C Source in Different Doses on Growth of Patin Pangasius Hypophthalmus Fingerlings

Directory of Open Access Journals (Sweden)

D. Jusadi

2007-01-01

Full Text Available This study was aimed to determine optimum dose of L-Ascorbyl-2-Phosphate Magnesium in the diet of patin, Pangasius hypophthalmus fingerlings.  Five isoprotein and isocaloric diets containing different dose of L-Ascorbyl-2-Phosphate Magnesium, i.e. 0, 25, 75 and 100 mg/kg diet were used in this experiment.  Fish with an average size of 5.00±0.11 g were maintained at a density of 15 fish per aquarium.  Fish were fed three times a day at satiation, for 40 days.  The results of study shows that vitamin C content in fish body increased as the vitamin C level of the diet increased.  Similar pattern to vitamin C content was also found in protein retention, lipid retention, daily growth rate, and feed efficiency (p Keywords: vitamin C, patin, Pangasius hypophthalmus.   ABSTRAK Penelitian ini bertujuan untuk menentukan kadar optimum L-Ascorbyl-2-Phosphate Magnesium dalam pakan ikan patin, Pangasius hypophthalmus ukuran sejari. Lima macam pakan isoprotein dan isokalori mempunyai kandungan L-Ascorbyl-2-Phosphate Magnesium berbeda, berturut-turut 0, 25, 50, 75 dan 100 mg/kg pakan telah digunakan dalam penelitian ini. Benih berukuran rata-rata 5,00±0,11 g dipelihara dalam akuarium dengan kepadatan 15 ekor per akuarium. Ikan diberi pakan tiga kali sehari, secara at satiation, selama 40 hari. Hasil penelitian menunjukkan bahwa kadar vitamin C tubuh meningkat sejalan dengan kadar vitamin C pakan. Demikian pula retensi protein, retensi lemak laju pertumbuhan harian, efisiensi pakan mengikuti pola yang sama seperti kandungan vitamin C tubuh (p Kata kunci: vitamin C, ikan patin, Pangasius hypophthalmus.

Magnitude and nature of the quadratic electro-optic effect in potassium dihydrogen phosphate and ammonium dihydrogen phosphate crystals

International Nuclear Information System (INIS)

Gunning, Mark J.; Raab, Roger E.; Kucharczyk, Wlodimierz

2001-01-01

Measurements of the magnitude and the sign of certain quadratic electro-optic coefficients of potassium dihydrogen phosphate (KDP) and ammonium dihydrogen phosphate (ADP) were made with an actively stabilized Michelson interferometer. The results obtained for these coefficients are, in units of 10 -20 m 2 V -2 (as opposed to literature values of order 10 -18 m 2 V -2 ), as follows: (KDP)g xxxx =-3.4±0.5, g yyxx =-0.2±0.4, and g zzxx =-0.7±0.4; (ADP)g xxxx =-7.4±1.0, g yyxx =-1.7±0.9, and g zzxx =-1.4±0.9. The quadratic Faust--Henry coefficient describing the lattice and the electronic contributions to the quadratic electro-optic effect in KDP and ADP is estimated from our results. These show that the nonlinear susceptibility responsible for the quadratic electro-optic effect in these crystals is due mainly to nonlinear interactions of the low-frequency electric field with the crystal lattice. Copyright 2001 Optical Society of America

Effect of surface treatment on the corrosion properties of magnesium-based fibre metal laminate

Science.gov (United States)

Zhang, X.; Zhang, Y.; Ma, Q. Y.; Dai, Y.; Hu, F. P.; Wei, G. B.; Xu, T. C.; Zeng, Q. W.; Wang, S. Z.; Xie, W. D.

2017-02-01

The surface roughness, weight of phosphating film and wettability of magnesium alloy substrates after abrasion and phosphating treatment were investigated in this work. The interfacial bonding and corrosion properties of a magnesium-based fibre metal laminate (MgFML) were analysed. The results showed that the wettability of the magnesium alloy was greatly influenced by the surface roughness, and the rough surface possessed a larger surface energy and better wettability. The surface energy and wettability of the magnesium alloy were significantly improved by the phosphating treatment. After phosphating for 5 min, a phosphating film with a double-layer structure was formed on the magnesium substrate, and the weight of the phosphating film and the surface energy reached their maximum values. The surface energies of the phosphated substrate after abrasion with #120 and #3000 grit abrasive papers were 84.31 mJ/m2 and 83.65 mJ/m2, respectively. The wettability of the phosphated magnesium was significantly better than the abraded magnesium. The phosphated AZ31B sheet had a better corrosion resistance than the abraded AZ31B sheet within short times. The corrosion resistance of the magnesium alloy was greatly increased by being composited with glass fibre/epoxy prepregs.

Molybdate/phosphate composite conversion coating on magnesium alloy surface for corrosion protection

International Nuclear Information System (INIS)

Yong Zhiyi; Zhu Jin; Qiu Cheng; Liu Yali

2008-01-01

In this paper, a new conversion coating-molybdate/phosphate (Mo/P) coating on magnesium alloy was prepared and investigated by electrochemical impedance spectra (EIS), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and salt-water immersion experiments, respectively. The results demonstrated that the Mo/P coating contained composite phases, which were consisted of metaphosphate as well as molybdate oxide with an 'alveolate-crystallized' structure. The composite Mo/P conversion coating had better corrosion resistance performance than molybdate (Mo) coating, and even had almost comparable corrosion protection for Mg alloy to the traditional chromate-based coating.

Synthesis, characterization, and in-vitro cytocompatibility of amorphous β-tri-calcium magnesium phosphate ceramics

Energy Technology Data Exchange (ETDEWEB)

Singh, Satish S., E-mail: sss42@pitt.edu [Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Roy, Abhijit, E-mail: abr20@pitt.edu [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Lee, Boeun, E-mail: bol11@pitt.edu [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Banerjee, Ipsita [Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Kumta, Prashant N., E-mail: pkumta@pitt.edu [Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Center for Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Department of Mechanical Engineering and Materials Science, University of Pittsburgh, PA 15261 (United States)

2016-10-01

Biphasic mixtures of crystalline β-tricalcium magnesium phosphate (β-TCMP) and an amorphous calcium magnesium phosphate have been synthesized and reported to support enhanced hMSC differentiation in comparison to β-tricalcium phosphate (β-TCP) due to the release of increased amounts of bioactive ions. In the current study, completely amorphous β-TCMP has been synthesized which is capable of releasing increased amounts of Mg{sup 2+} and PO{sub 4}{sup 3−} ions, rather than a biphasic mixture as earlier reported. The amorphous phase formed was observed to crystallize between temperatures of 400–600 °C. The scaffolds prepared with amorphous β-TCMP were capable of supporting enhanced hMSC proliferation and differentiation in comparison to commercially available β-TCP. However, a similar gene expression of mature osteoblast markers, OCN and COL-1, in comparison to biphasic β-TCMP was observed. To further study the role of Mg{sup 2+} and PO{sub 4}{sup 3−} ions in regulating hMSC osteogenic differentiation, the capability of hMSCs to mineralize in growth media supplemented with Mg{sup 2+} and PO{sub 4}{sup 3−} ions was studied. Interestingly, 5 mM PO{sub 4}{sup 3−} supported mineralization while the addition of 5 mM Mg{sup 2+} to 5 mM PO{sub 4}{sup 3−} inhibited mineralization. It was therefore concluded that the release of Ca{sup 2+} ions from β-TCMP scaffolds also plays a role in regulating osteogenic differentiation on these scaffolds and it is noted that further work is required to more accurately determine the exact role of Mg{sup 2+} in regulating hMSC osteogenic differentiation. - Highlights: • Synthesis of amorphous Mg containing beta tricalcium phosphate ceramics • Amorphous beta TCMP supports enhanced hMSC proliferation and differentiation. • Amorphous beta TCMP shows comparable OCN and COL-1 expression to biphasic TCMP. • Presence of 5 mM Mg{sup 2+} and PO{sub 4}{sup 3−} ions in growth media inhibits hMSC mineralization.

Capacity and mechanisms of ammonium and cadmium sorption on different wetland-plant derived biochars

International Nuclear Information System (INIS)

Cui, Xiaoqiang; Hao, Hulin; Zhang, Changkuan; He, Zhenli; Yang, Xiaoe

2016-01-01

The objective of this study was to investigate the relationship between Cd 2+ /NH 4 + sorption and physicochemical properties of biochars produced from different wetland plants. Biochars from six species of wetland plants (i.e., Canna indica, Pennisetum purpureum Schum, Thalia dealbata, Zizania caduciflora, Phragmites australis and Vetiveria zizanioides) were obtained at 500 °C and characterized, and their sorption for ammonium and cadmium was determined. There were significant differences in elemental composition, functional groups and specific surface area among the biochars derived from different wetland plant species. Sorption of ammonium and cadmium on the biochars could be described by a pseudo second order kinetic model, and the simple Langmuir model fits the isotherm data better than the Freundlich or Temkin model. The C. indica derived biochar had the largest sorption capacity for NH 4 + and Cd 2+ , with a maximum sorption of 13.35 and 125.8 mg g −1 , respectively. P. purpureum Schum derived biochar had a similar maximum sorption (119.3 mg g −1 ) for Cd 2+ . Ammonium sorption was mainly controlled by cation exchange, surface complexation with oxygen-containing functional groups and the formation of magnesium ammonium phosphate compounds, whereas for Cd 2+ sorption, the formation of cadmium phosphate precipitates, cation exchange and binding to oxygen-containing groups were the major possible mechanisms. In addition, the sorption of ammonium and cadmium was not affected by surface area and microporosity of the biochars. - Highlights: • Biochars varied in physicochemical properties and adsorption capacity. • Canna indica derived biochar has a high sorption capacity for Cd 2+ . • NH 4 + and Cd 2+ sorption on biochars fits a pseudo second order and Langmuir model. • Sorption mechanism is related to complexation, cation exchange and precipitation.

Capacity and mechanisms of ammonium and cadmium sorption on different wetland-plant derived biochars

Energy Technology Data Exchange (ETDEWEB)

Cui, Xiaoqiang [Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Hao, Hulin [Ningbo Raw Water Resource Research Academy, Ningbo (China); Zhang, Changkuan [Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); He, Zhenli [Indian River Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Fort Pierce, FL 34945 (United States); Yang, Xiaoe, E-mail: xyang571@yahoo.com [Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China)

2016-01-01

The objective of this study was to investigate the relationship between Cd{sup 2+}/NH{sub 4}{sup +} sorption and physicochemical properties of biochars produced from different wetland plants. Biochars from six species of wetland plants (i.e., Canna indica, Pennisetum purpureum Schum, Thalia dealbata, Zizania caduciflora, Phragmites australis and Vetiveria zizanioides) were obtained at 500 °C and characterized, and their sorption for ammonium and cadmium was determined. There were significant differences in elemental composition, functional groups and specific surface area among the biochars derived from different wetland plant species. Sorption of ammonium and cadmium on the biochars could be described by a pseudo second order kinetic model, and the simple Langmuir model fits the isotherm data better than the Freundlich or Temkin model. The C. indica derived biochar had the largest sorption capacity for NH{sub 4}{sup +} and Cd{sup 2+}, with a maximum sorption of 13.35 and 125.8 mg g{sup −1}, respectively. P. purpureum Schum derived biochar had a similar maximum sorption (119.3 mg g{sup −1}) for Cd{sup 2+}. Ammonium sorption was mainly controlled by cation exchange, surface complexation with oxygen-containing functional groups and the formation of magnesium ammonium phosphate compounds, whereas for Cd{sup 2+} sorption, the formation of cadmium phosphate precipitates, cation exchange and binding to oxygen-containing groups were the major possible mechanisms. In addition, the sorption of ammonium and cadmium was not affected by surface area and microporosity of the biochars. - Highlights: • Biochars varied in physicochemical properties and adsorption capacity. • Canna indica derived biochar has a high sorption capacity for Cd{sup 2+}. • NH{sub 4}{sup +} and Cd{sup 2+} sorption on biochars fits a pseudo second order and Langmuir model. • Sorption mechanism is related to complexation, cation exchange and precipitation.

Corrosion and erosion properties of silicate and phosphate coatings on magnesium

International Nuclear Information System (INIS)

Ma, Y.; Nie, X.; Northwood, D.O.; Hu, H.

2004-01-01

Electrolytic plasma processing (EPP) is an emerging, environmentally friendly, surface engineering technique. In this study, we have utilized the EPP technique to deposit silicate and phosphate coatings on magnesium for both corrosion and erosion protection. Potentiodynamic polarization measurements were used to investigate the corrosion properties of the coated samples. A stirring device was also used for corrosion and erosion testing. Coated and uncoated samples were immersed in a 3.5 wt.% NaCl solution with SiO 2 sand in suspension and rotated at a given speed. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis were used to study surface morphology and chemical composition of the coatings before and after corrosion-erosion testing

Solid-state reaction kinetics of neodymium doped magnesium hydrogen phosphate system

Science.gov (United States)

Gupta, Rashmi; Slathia, Goldy; Bamzai, K. K.

2018-05-01

Neodymium doped magnesium hydrogen phosphate (NdMHP) crystals were grown by using gel encapsulation technique. Structural characterization of the grown crystals has been carried out by single crystal X-ray diffraction (XRD) and it revealed that NdMHP crystals crystallize in orthorhombic crystal system with space group Pbca. Kinetics of the decomposition of the grown crystals has been studied by non-isothermal analysis. The estimation of decomposition temperatures and weight loss has been made from the thermogravimetric/differential thermo analytical (TG/DTA) in conjuncture with DSC studies. The various steps involved in the thermal decomposition of the material have been analysed using Horowitz-Metzger, Coats-Redfern and Piloyan-Novikova equations for evaluating various kinetic parameters.

Efficacy Of Trichloro-acetic Acid Peel Alone Versus Combined Topical Magnesium Ascorbyl Phosphate For Epidermal Melasma

International Nuclear Information System (INIS)

Murtaza, F.; Noor, S. M.; Bangash, A. R.

2016-01-01

Objective: To compare the efficacy in terms of reduction in melasma area and severity index (MASI) score by more than 10 of a combination of 20% trichloro-acetic acid peel plus 5% topical magnesium ascorbyl phosphate versus 20 percent trichloroacetic acid peel alone in the treatment of epidermal melasma. Study Design: Randomized controlled trial. Place and Duration of Study: Department of Dermatology, Lady Reading Hospital (LRH), Peshawar, from May 2012 to May 2013. Methodology: Patients aged 18 - 65 years, with Fitzpatrick skin type III-V were divided into two equal groups having 74 patients each. Detailed history was taken and Wood's lamp examination done to rule out mixed and dermal melasma. Melasma area and severity index (MASI) score was calculated for every patient. Priming was done for all patients with tretinoin cream applied once daily at night for 2 weeks, and to use a broad spectrum sun block cream before sun exposure. Patients in group A were subjected to combined treatment, i.e. trichloro-acetic acid peel 20 percent (weekly) plus magnesium ascorbyl phosphate cream (applied once daily), while patients in group B were subjected to trichloro-acetic acid peel 20 percent (weekly) alone. Treatment was continued for 6 weeks. After completion of treatment, MASI score was recalculated. Proportion of patients with significant MASI score reduction was compared using chi-square test with significance at p < 0.05. Results: Male and female patients were 11 (14.9 percent) and 63 (85.1 percent), respectively in group A, whereas 13 (17.6 percent) and 61 (82.4 percent) in group B. The mean age in group A was 30.28±8.08 years, and 29.36±6.84 years in group B. Significant MASI score reduction in group A was seen in 60 (81.1 percent) patients and in group B 49 (66.2 percent, p= 0.040). Conclusion: Combination of trichloro-acetic acid peel and topical magnesium ascorbyl phosphate cream was significantly more effective than trichloro-acetic acid peel alone in

Immobilisation of radio cesium loaded ammonium molybdo phosphate in glass matrices

International Nuclear Information System (INIS)

Yalmali, Vrunda S.; Singh, I.J.; Sathi Sasidharan, N.; Deshingkar, D.S.

2004-11-01

Long half life and easy availability from high level wastes make 137 Cesium most economical radiation source. High level liquid waste processing for 137 Cesium removal has become easier due to development of Cesium specific granulated ammonium molybdophosphate (AMP) composite. In such applications, resulting spent composite AMP itself represents high active solid waste and immobilization of these materials in cement may not be acceptable. Studies on immobilization of 137 Cs loaded AMP were taken up in order to achieve twin goals of increasing safety and minimizing processing costs of the final matrix. Studies indicated that phosphate modified sodium borosilicate SPNM glasses prepared under usual oxidizing conditions are not suitable for immobilization of 137 Cs loaded on AMP .Phosphate glasses containing Na 2 O, P 2 O 5 , B 2 O 3 , Fe 2 O 3 , Al 2 O 3 and SiO 2 as major constituents are capable of incorporating 6 to 8 % AMP. The Normalized Leach rates of these glasses for sodium, cesium, boron and silica are 10 -4 to 10 -6 gm/cm 2 /day which are comparable to or better than those reported for NBS glasses incorporating HLW. Homogeneity of the final matrix was confirmed by x-ray diffraction analysis. Further studies on characterization of these glasses would establish their acceptability. (author)

Dynamics and diversity of phosphate mineralizing bacteria in the coral reefs of Gulf of Mannar

Digital Repository Service at National Institute of Oceanography (India)

Kannapiran, E.; Ravindran, J.

.2g, Ammonium sulphate 0.5g, Magnesium sulphate 0.1g, Potassium chloride 0.2g, Dextrose 10g, Soil extract 200ml, Distilled water 800ml, Trace element 1ml, Agar 18g and pH 7.2±0.1) [11] was used for the enumeration of Inorganic Phosphate Solubilizing... The biological decomposition of organic phosphorus in the marine environment is considered as the result of bacterial action and rate of decomposition of organic phosphorus by bacteria depend on the density of the phosphatase producing bacterial population [14...

Metal cation controls phosphate release in the myosin ATPase.

Science.gov (United States)

Ge, Jinghua; Huang, Furong; Nesmelov, Yuri E

2017-11-01

Myosin is an enzyme that utilizes ATP to produce a conformational change generating a force. The kinetics of the myosin reverse recovery stroke depends on the metal cation complexed with ATP. The reverse recovery stroke is slow for MgATP and fast for MnATP. The metal ion coordinates the γ phosphate of ATP in the myosin active site. It is accepted that the reverse recovery stroke is correlated with the phosphate release; therefore, magnesium "holds" phosphate tighter than manganese. Magnesium and manganese are similar ions in terms of their chemical properties and the shell complexation; hence, we propose to use these ions to study the mechanism of the phosphate release. Analysis of octahedral complexes of magnesium and manganese show that the partial charge of magnesium is higher than that of manganese and the slightly larger size of manganese ion makes its ionic potential smaller. We hypothesize that electrostatics play a role in keeping and releasing the abstracted γ phosphate in the active site, and the stronger electric charge of magnesium ion holds γ phosphate tighter. We used stable myosin-nucleotide analog complex and Raman spectroscopy to examine the effect of the metal cation on the relative position of γ phosphate analog in the active site. We found that in the manganese complex, the γ phosphate analog is 0.01 nm further away from ADP than in the magnesium complex. We conclude that the ionic potential of the metal cation plays a role in the retention of the abstracted phosphate. © 2017 The Protein Society.

Low-temperature setting phosphate ceramics for stabilization of DOE problem low level mixed-waste: I. Material and waste form development

International Nuclear Information System (INIS)

Singh, D.; Wagh, A.; Knox, L.; Mayberry, J.

1994-03-01

Chemically bonded phosphate ceramics are proposed as candidates for solidification and stabilization of some of the open-quotes problemclose quotes DOE low-level mixed wastes at low-temperatures. Development of these materials is crucial for stabilization of waste streams which have volatile species and any use of high-temperature technology leads to generation of off-gas secondary waste streams. Several phosphates of Mg, Al, and Zr have been investigated as candidate materials. Monoliths of these phosphates were synthesized using chemical routes at room or slightly elevated temperatures. Detailed physical and chemical characterizations have been conducted on some of these phosphates to establish their durability. Magnesium ammonium phosphate has shown to possess excellent mechanical and as well chemical properties. These phosphates were also used to stabilize a surrogate ash waste with a loading ranging from 25-35 wt.%. Characterization of the final waste forms show that waste immobilization is due to both chemical stabilization and physical encapsulation of the surrogate waste which is desirable for waste immobilization

Photometric Determination of Ammonium and Phosphate in Seawater Medium Using a Microplate Reader.

Science.gov (United States)

Ruppersberg, Hanna S; Goebel, Maren R; Kleinert, Svea I; Wünsch, Daniel; Trautwein, Kathleen; Rabus, Ralf

2017-01-01

To more efficiently process the large sample numbers for quantitative determination of ammonium (NH4+) and phosphate (orthophosphate, PO43-) generated during comprehensive growth experiments with the marine Roseobacter group member Phaeobacter inhibens DSM 17395, specific colorimetric assays employing a microplate reader (MPR) were established. The NH4+ assay is based on the reaction of NH4+ with hypochlorite and salicylate, yielding a limit of detection of 14 µM, a limit of quantitation of 36 µM, and a linear range for quantitative determination up to 200 µM. The PO43-assay is based on the complex formation of PO43- with ammonium molybdate in the presence of ascorbate and zinc acetate, yielding a limit of detection of 13 µM, a limit of quantitation of 50 µM, and a linear range for quantitative determination up to 1 mM. Both MPR-based assays allowed for fast (significantly lower than 1 h) analysis of 21 samples plus standards for calibration (all measured in triplicates) and showed only low variation across a large collection of biological samples. © 2017 S. Karger AG, Basel.

Magnesium Counteracts Vascular Calcification: Passive Interference or Active Modulation?

Science.gov (United States)

Ter Braake, Anique D; Shanahan, Catherine M; de Baaij, Jeroen H F

2017-08-01

Over the last decade, an increasing number of studies report a close relationship between serum magnesium concentration and cardiovascular disease risk in the general population. In end-stage renal disease, an association was found between serum magnesium and survival. Hypomagnesemia was identified as a strong predictor for cardiovascular disease in these patients. A substantial body of in vitro and in vivo studies has identified a protective role for magnesium in vascular calcification. However, the precise mechanisms and its contribution to cardiovascular protection remain unclear. There are currently 2 leading hypotheses: first, magnesium may bind phosphate and delay calcium phosphate crystal growth in the circulation, thereby passively interfering with calcium phosphate deposition in the vessel wall. Second, magnesium may regulate vascular smooth muscle cell transdifferentiation toward an osteogenic phenotype by active cellular modulation of factors associated with calcification. Here, the data supporting these major hypotheses are reviewed. The literature supports both a passive inorganic phosphate-buffering role reducing hydroxyapatite formation and an active cell-mediated role, directly targeting vascular smooth muscle transdifferentiation. However, current evidence relies on basic experimental designs that are often insufficient to delineate the underlying mechanisms. The field requires more advanced experimental design, including determination of intracellular magnesium concentrations and the identification of the molecular players that regulate magnesium concentrations in vascular smooth muscle cells. © 2017 American Heart Association, Inc.

Characterization of Porous Phosphate Coatings Enriched with Magnesium or Zinc on CP Titanium Grade 2 under DC Plasma Electrolytic Oxidation

Directory of Open Access Journals (Sweden)

Krzysztof Rokosz

2018-02-01

Full Text Available The aim of the paper is to study and determine the effect of voltage increasing from 500 up to 650 VDC on chemical and electrochemical properties of the obtained porous coatings with plasma electrolytic oxidation (PEO processes, known also as micro arc oxidation (MAO. In the present paper, the chemical and electrochemical characterization of porous phosphate coatings enriched with magnesium or zinc on commercially pure (CP Titanium Grade 2 under DC-PEO obtained in electrolytes based on concentrated 85% analytically pure H3PO4 (98 g/mole acid with additions of 500 g·L−1 of zinc nitrate Zn(NO32∙6H2O or magnesium nitrate Mg(NO32∙6H2O, are described. These materials were characterized using scanning electron microscope (SEM with energy-dispersive X-ray spectroscopy (EDS, X-ray photoelectron spectroscopy (XPS and glow discharge optical emission spectroscopy (GDOES. It was found that the voltage of PEO process has influence on the chemical composition and thickness of the obtained porous coatings as well as on their electrochemical behavior. The higher the potential of PEO treatment, the higher the amount of zinc-to-phosphorus ratio for zinc enriched coatings was obtained, whereas in magnesium enriched coatings, the average amount of magnesium detected in PEO coating is approximately independent of the PEO voltages. Based on XPS studies, it was found out that most likely the top 10 nm of porous coatings is constructed of titanium (Ti4+, magnesium (Mg2+, zinc (Zn2+, and phosphates PO43− and/or HPO42− and/or H2PO4− and/or P2O74−. On the basis of GDOES studies, a four-sub-layer model of PEO coatings is proposed. Analysis of the potentiodynamic corrosion curves allowed to conclude that the best electrochemical repeatability was noted for magnesium and zinc enriched coatings obtained at 575 VDC.

EPR and optical studies of Cu2+ ions doped in magnesium potassium phosphate hexahydrate single crystals

International Nuclear Information System (INIS)

Kripal, Ram; Shukla, Santwana

2011-01-01

An electron paramagnetic resonance (EPR) study of Cu 2+ -doped magnesium potassium phosphate is performed at liquid nitrogen temperature (LNT; 77 K). Two magnetically non-equivalent sites for Cu 2+ are observed. The spin Hamiltonian parameters are determined with the fitting of spectra to a rhombic symmetry crystalline field. The ground state wavefunction is also determined. The g-anisotropy is evaluated and compared with the experimental value. With the help of an optical study, the nature of the bonding in the complex is discussed.

Microstructure of hydroxyapatite- and octacalcium phosphate-coatings formed on magnesium by a hydrothermal treatment at various pH values

International Nuclear Information System (INIS)

Tomozawa, Masanari; Hiromoto, Sachiko

2011-01-01

Hydroxyapatite (HAp) coatings with and without octacalcium phosphate (OCP) were uniformly formed on pure magnesium by a hydrothermal treatment using a Ca-EDTA solution. The crystal structure, crystallographic orientation and lattice images were investigated using transmission electron microscopy (TEM) and high-resolution TEM. It was demonstrated that the crystal phase and microstructure of the calcium phosphate-coatings can vary with the pH of the treatment solution. In a weak acid treatment solution, a dual-layer structure was formed: an outer coarse layer consisting of plate-like OCP crystals and an inner dense layer consisting primarily of HAp crystals. One piece of the OCP plate corresponded to a single OCP crystal growing parallel to the (1 0 0) OCP . In a weak alkali treatment solution, a dual-layer structure was also formed: an outer coarse layer consisting of rod-like HAp crystals and an inner dense layer consisting of HAp crystals. One piece of the HAp rod corresponded to a single HAp crystal growing along [0 0 2] HAp . In a strong alkali treatment solution, needle-like HAp crystals were formed. No defect was observed in the lattice image of the OCP and HAp. The corrosion current density of pure magnesium in a 3.5 wt.% NaCl solution decreased with the HAp coating more significantly than the OCP + HAp coating. It is revealed that the degree of protection afforded by calcium phosphate-coatings varies with their crystal phase and microstructure.

Properties of porous magnesium prepared by powder metallurgy.

Science.gov (United States)

Čapek, Jaroslav; Vojtěch, Dalibor

2013-01-01

Porous magnesium-based materials are biodegradable and promising for use in orthopaedic applications, but their applications are hampered by their difficult fabrication. This work reports the preparation of porous magnesium materials by a powder metallurgy technique using ammonium bicarbonate as spacer particles. The porosity of the materials depended on the amount of ammonium bicarbonate and was found to have strong negative effects on flexural strength and corrosion behaviour. However, the flexural strength of materials with porosities of up to 28 vol.% was higher than the flexural strength of non-metallic biomaterials and comparable with that of natural bone. Copyright © 2012 Elsevier B.V. All rights reserved.

The effects to the structure and electrochemical behavior of zinc phosphate conversion coatings with ethanolamine on magnesium alloy AZ91D

International Nuclear Information System (INIS)

Li Qing; Xu Shuqiang; Hu Junying; Zhang Shiyan; Zhong Xiankang; Yang Xiaokui

2010-01-01

This paper discussed a zinc phosphate conversion coating formed on magnesium alloy AZ91D from the phosphating bath with varying amounts of ethanolamine (MEA). The effects of MEA on the form, structure, phase composition and electrochemical behavior of the phosphate coatings were examined using an scanning electron microscopy (SEM), X-ray diffraction (XRD) potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) measurements. Interpretations of the electrical elements of the equivalent circuit were obtained from the SEM structure of the coatings, assumed to be formed of two layers: an outer porous crystal layer and an inner flat amorphous layer. The result showed that adding MEA refined the microstructure of the crystal layer and that the phosphate coating, derived at the optimal content of 1.2 g/L, with the most uniform and compact outer crystal layer provided the best corrosion protection.

Effect of alkaline earth metal and magnesium cations on cadmium extraction from chloride solutions by tributyl phosphate

International Nuclear Information System (INIS)

Prokuev, V.A.; Belousov, E.A.

1985-01-01

At 298 K thermodynamic constants of cadmium (2) extraction from chloride solutions of magnesium, calcium, strontium and barium by tributyl phosphate are calculated. It is established, that logarithm of the thermodynamic extraction constant is in a linear dependence from the change in the cation hydration enthalpy in agqueous solution. It is shown, that activity coefficient of neutral complex CdVCl 2 differs from one, and it is the higher the more stable the complex is in alkaline earth metal chloride solutions

Improved Spectra for MALDI MSI of Peptides Using Ammonium Phosphate Monobasic in MALDI Matrix.

Science.gov (United States)

Ucal, Yasemin; Ozpinar, Aysel

2018-05-10

MALDI mass spectrometry imaging (MSI) enables analysis of peptides along with histology. However, there are several critical steps in MALDI MSI of peptides, one of which is spectral quality. Suppression of MALDI matrix clusters by the aid of ammonium salts in MALDI experiments is well-known. It is asserted that addition of ammonium salts dissociates potential matrix adducts and thereafter decreases matrix cluster formation. Consequently, MALDI MS sensitivity and mass accuracy increases. Up to our knowledge, a limited number of MALDI MSI studies used ammonium salts as matrix additives to suppress matrix clusters and enhance peptide signals. In this work, we investigated the effect of ammonium phosphate monobasic (AmP) as alpha-cyano-4-hydroxycinnamic acid (α-CHCA) matrix additive in MALDI MSI of peptides. Prior to MALDI MSI, the effect of varying concentrations of AmP in α-CHCA were assessed in bovine serum albumin (BSA) tryptic digests and compared with the control (α-CHCA without AmP). Based on our data, the addition of AmP as matrix additive decreased matrix cluster formation regardless of its concentration and, specifically 8 mM AmP and 10 mM AmP increased BSA peptide signal intensities. In MALDI MSI of peptides, both 8 mM, and 10 mM AmP in α-CHCA improved peptide signals especially in the mass range of m/z 2000 to 3000. In particular, 9 peptide signals were found to have differential intensities within the tissues deposited with AmP in α-CHCA (AUC>0.60). To the best of our knowledge, this is the first MALDI MSI of peptides work investigating different concentrations of AmP as α-CHCA matrix additive in order to enhance peptide signals in formalin fixed paraffin embedded (FFPE) tissues. Further, AmP as part of α-CHCA matrix could enhance protein identifications and support MALDI MSI based proteomic approaches. This article is protected by copyright. All rights reserved.

Influence of lead on stabilization/solidification by ordinary Portland cement and magnesium phosphate cement.

Science.gov (United States)

Wang, Yan-Shuai; Dai, Jian-Guo; Wang, Lei; Tsang, Daniel C W; Poon, Chi Sun

2018-01-01

Inorganic binder-based stabilization/solidification (S/S) of Pb-contaminated soil is a commonly used remediation approach. This paper investigates the influences of soluble Pb species on the hydration process of two types of inorganic binders: ordinary Portland cement (OPC) and magnesium potassium phosphate cement (MKPC). The environmental leachability, compressive strength, and setting time of the cement products are assessed as the primary performance indicators. The mechanisms of Pb involved in the hydration process are analyzed through X-ray diffraction (XRD), hydration heat evolution, and thermogravimetric analyses. Results show that the presence of Pb imposes adverse impact on the compressive strength (decreased by 30.4%) and the final setting time (prolonged by 334.7%) of OPC, but it exerts much less influence on those of MKPC. The reduced strength and delayed setting are attributed to the retarded hydration reaction rate of OPC during the induction period. These results suggest that the OPC-based S/S of soluble Pb mainly depends on physical encapsulation by calcium-silicate-hydrate (CSH) gels. In contrast, in case of MKPC-based S/S process, chemical stabilization with residual phosphate (pyromorphite and lead phosphate precipitation) and physical fixation of cementitious struvite-K are the major mechanisms. Therefore, MKPC is a more efficient and chemically stable inorganic binder for the Pb S/S process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Efficiency of ammonium nitrate phosphates of varying water-soluble phosphorus content for rice and succeeding maize crop on contrasting soil types

International Nuclear Information System (INIS)

Bhujbal, B.M.; Mistry, K.B.; Chapke, V.G.; Mutatkar, V.K.

1977-01-01

Efficiency of ammonium nitrate phosphates (ANP) containing 30 and 50 percent of water-soluble phosphorus (W.S.P.) vis-a-vis that of entirely water-soluble monoammonium orthophosphate (MAP) for rice and succeeding maize crop on phosphate responsive laterite, red sandy loam (Chalka) and calcareous black soils was examined in greenhouse experiments. Data on dry matter yield, uptake of phosphorus, utilization of applied fertilizer, 'Effective Rate of Application' and 'Relative Efficiency percent' at flowering stage of rice indicated no significant differences between ammonium nitrate phosphate (30 percent and 50 percent water-soluble ohosphorus) and monoammonium orthophosphate (MAP) on laterits and natural red sandy loam soils. MAP was significantly superior to the two ANP fertilizers on calcareous black soil; no significant differences were observed between ANP (30 percent W.S.P.) and ANP (50 percent W.S.P.) on this soil. The succeeding maize crop grown up to flowering in the same pots indicated that the residual value of ANP (30 percent W.S.P.) was equal or superior to that of MAP on the laterits as well as calcareous black soil. No significant differences were detected between the residual values of the two water-solubility grades of ANP. Incubation under submerged conditions for periods upto 60 days showed that 0.5 M NaHCO 3 (pH 8.5) extractable phosphorus (plant-available phosphate) in the ANP (30 percent W.S.P.) treatment was, in general, equal to those in the MAP treatments in the laterite and red sandy loam but was significantly lower in the calcareous black soil. No marked differences were observed between the effects of the two ANP fertilizers. (author)

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

Science.gov (United States)

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

2015-05-01

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.

Chemical stabilisation of lead in shooting range soils with phosphate and magnesium oxide: Synchrotron investigation

International Nuclear Information System (INIS)

Sanderson, Peter; Naidu, Ravi; Bolan, Nanthi; Lim, Jung Eun; Ok, Yong Sik

2015-01-01

Highlights: • Quantitative speciation of Pb by XAS as a result of Phosphate and MgO treatment revealed Pb converted to pyromorphite was limited. • Subsequent MgO addition increased pyromorphite formation. • Pb was precipitated on the surface of MgO as PbO. • Bioaccessibility of Pb decreased with P treatments, but not with MgO only. - Abstract: Three Australian shooting range soils were treated with phosphate and magnesium oxide, or a combination of both to chemically stabilize Pb. Lead speciation was determined after 1 month ageing by X-ray absorption spectroscopy combined with linear combination fitting in control and treated soils. The predominant Pb species in untreated soils were iron oxide bound Pb, humic acid bound Pb and the mineral litharge. Treatment with phosphate resulted in substantial pyromorphite formation in two of the soils (TV and PE), accounting for up to 38% of Pb species present, despite the addition of excess phosphate. In MgO treated soils only, up to 43% of Pb was associated with MgO. Litharge and Pb hydroxide also formed as a result of MgO addition in the soils. Application of MgO after P treatment increased hydroxypyromorphite/pyromorphite formation relative to soils teated with phosphate only. X-ray diffraction and Scanning electron microscopy revealed PbO precipitate on the surface of MgO. Soil pH, (5.3–9.3) was an important parameter, as was the solubility of existing Pb species. The use of direct means of determination of the stabilisation of metals such as by X-ray absorption spectroscopy is desirable, particularly in relation to understanding long term stability of the immobilised contaminants.

Chemical stabilisation of lead in shooting range soils with phosphate and magnesium oxide: Synchrotron investigation

Energy Technology Data Exchange (ETDEWEB)

Sanderson, Peter [Centre for Environmental Risk Assessment and Remediation and CRC for Contamination Assessment and Remediation of the Environment (CRC CARE), University of South Australia, University Parade, 5095 Mawson Lakes (Australia); Naidu, Ravi, E-mail: ravi.naidu@crccare.com [Centre for Environmental Risk Assessment and Remediation and CRC for Contamination Assessment and Remediation of the Environment (CRC CARE), University of South Australia, University Parade, 5095 Mawson Lakes (Australia); Bolan, Nanthi [Centre for Environmental Risk Assessment and Remediation and CRC for Contamination Assessment and Remediation of the Environment (CRC CARE), University of South Australia, University Parade, 5095 Mawson Lakes (Australia); Lim, Jung Eun; Ok, Yong Sik [Korea Biochar Research Center & Department of Biological Environment, Kangwon National University, Chuncheon 200-701 (Korea, Republic of)

2015-12-15

Highlights: • Quantitative speciation of Pb by XAS as a result of Phosphate and MgO treatment revealed Pb converted to pyromorphite was limited. • Subsequent MgO addition increased pyromorphite formation. • Pb was precipitated on the surface of MgO as PbO. • Bioaccessibility of Pb decreased with P treatments, but not with MgO only. - Abstract: Three Australian shooting range soils were treated with phosphate and magnesium oxide, or a combination of both to chemically stabilize Pb. Lead speciation was determined after 1 month ageing by X-ray absorption spectroscopy combined with linear combination fitting in control and treated soils. The predominant Pb species in untreated soils were iron oxide bound Pb, humic acid bound Pb and the mineral litharge. Treatment with phosphate resulted in substantial pyromorphite formation in two of the soils (TV and PE), accounting for up to 38% of Pb species present, despite the addition of excess phosphate. In MgO treated soils only, up to 43% of Pb was associated with MgO. Litharge and Pb hydroxide also formed as a result of MgO addition in the soils. Application of MgO after P treatment increased hydroxypyromorphite/pyromorphite formation relative to soils teated with phosphate only. X-ray diffraction and Scanning electron microscopy revealed PbO precipitate on the surface of MgO. Soil pH, (5.3–9.3) was an important parameter, as was the solubility of existing Pb species. The use of direct means of determination of the stabilisation of metals such as by X-ray absorption spectroscopy is desirable, particularly in relation to understanding long term stability of the immobilised contaminants.

EPR and optical studies of Cu{sup 2+} ions doped in magnesium potassium phosphate hexahydrate single crystals

Energy Technology Data Exchange (ETDEWEB)

Kripal, Ram; Shukla, Santwana, E-mail: ram_kripal2001@rediffmail.com, E-mail: shukla.santwana@gmail.com [EPR Laboratory, Department of Physics, University of Allahabad, Allahabad 211002 (India)

2011-03-15

An electron paramagnetic resonance (EPR) study of Cu{sup 2+}-doped magnesium potassium phosphate is performed at liquid nitrogen temperature (LNT; 77 K). Two magnetically non-equivalent sites for Cu{sup 2+} are observed. The spin Hamiltonian parameters are determined with the fitting of spectra to a rhombic symmetry crystalline field. The ground state wavefunction is also determined. The g-anisotropy is evaluated and compared with the experimental value. With the help of an optical study, the nature of the bonding in the complex is discussed.

Magnesium analysis. Determination of 5 elements by impulse polarography

International Nuclear Information System (INIS)

Anon.

Determination of cadmium, copper, nickel, lead and zinc in magnesium used in magnesiothermics. The process is as follow: magnesium dissolution in hydrochloric acid, neutralisation by ammonia, addition of ammonium chloride and citric acid, ammonia is added until pH8. Addition of pyridine, polarographic determination of zinc and then of cadmium and copper [fr

Binding and uptake of {sup 125}iodine-labelled, oxidized low density lipoprotein by macrophages: Comparison of the effects of {alpha}-tocopherol, probucol, pyridoxal-5`-phosphate and magnesium-pyridoxal-5`-phosphate-glutamate

Energy Technology Data Exchange (ETDEWEB)

Selmer, D. [Technische Univ. Muenchen, Freising-Weihenstephan (Germany). Lehrstuhl fuer Phytopathologie; Senekowitsch-Schmidtke, R. [Technische Univ. Muenchen (Germany). Nuklearmedizinische Klinik; Schneider, W. [Steigerwald Arzneimittel, Darmstadt (Germany); Elstner, E.F. [Technische Univ. Muenchen, Freising-Weihenstephan (Germany). Lehrstuhl fuer Phytopathologie

1997-01-01

Specific and unspecific binding and uptake (internalization) by macrophages of {sup 125}iodine-labelled, copper-oxidized human low density lipoprotein is differently influenced by the anti-oxidants {alpha}-tocopherol ({alpha}-Toc), probucol (Prob), pyridoxal-5`-phosphate (PP) and the magnesium-pyridoxal-5`-phosphate glutamate complex (MPPG). Binding as well as internalization, mediated by the so-called `scavenger receptor` is lower in the presence of MPPG whereas both specific binding and internalization are enhanced. The comparison of the effects in vitro allows a rating of the potentially anti-atherogenic and thus protective effects of the tested substances as follows: MPPG>PP>{alpha}-Toc>Prob. (orig.)

Ammonium and phosphate enrichment across the dry-wet transition and their ecological relevance in a subtropical reservoir, China.

Science.gov (United States)

Mo, Qiongli; Chen, Nengwang; Zhou, Xingpeng; Chen, Jixin; Duan, Shuiwang

2016-07-13

Small river reservoirs are widespread and can be ecologically sensitive across the dry-wet transition under monsoon climate with respect to nutrient loading and phenology. Monthly sampling and high-frequency in situ measurements were conducted for a river reservoir (southeast China) in 2013-2014 to examine the seasonal pattern of nutrients and phytoplankton. We found that nutrient concentrations were runoff-mediated and determined by watershed inputs and, in some cases, by internal cycling depending on hydrology and temperature. Ammonium and phosphate were relatively enriched in February-March (a transitional period from dry/cold to wet/hot climate), which can be ascribed to initial flushing runoff from human/animal waste and spring fertilizer use. A phytoplankton bloom (mainly Chlorophyta) occurred during April after a surge of water temperature, probably due to the higher availability of inorganic nutrients and sunlight and suitable hydraulic residence time (medium flow) in the transitional period. The concentration of phytoplankton was low during May-June (wet-hot climate) when the concentrations of total suspended matter (TSM) were highest, likely owing to the "shading" effect of TSM and turbulence of high flow conditions. Nutrient-algae shifts across the dry-wet season and vertical profiles suggested that algal blooms seem to be fueled primarily by phosphate and ammonium rather than nitrate. Current findings of a strong temporal pattern and the relationship between physical parameters, nutrient and biota would improve our understanding of drivers of change in water quality and ecosystem functions with dam construction.

Chemical synthesis and stabilization of magnesium substituted brushite

Energy Technology Data Exchange (ETDEWEB)

Lee, Donghyun [Department of Biomedical Engineering, Chung-Ang University, 221 Heukseok-Dong, Dongjak-Gu, Seoul 156-756 (Korea, Republic of); Kumta, Prashant N., E-mail: pkumta@pitt.edu [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Department of Mechanical Engineering and Materials Sceince, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15260 (United States)

2010-08-30

Hydroxyapatite (Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}) is the most ubiquitous calcium phosphate phase used in implant coatings and more recently in gene/drug delivery applications due to its chemical stability under normal physiological conditions (37 deg. C, pH {approx} 7.5, 1 atm.). However, different calcium phosphate phases, such as brushite (CaH(PO{sub 4}){center_dot}2(H{sub 2}O)) and tricalcium phosphate (Ca{sub 3}(PO{sub 4}){sub 2}) which are thermodynamically unstable under physiological conditions are also being explored for biomedical applications. One way of stabilizing these phases under physiological conditions is to introduce magnesium to substitute for calcium in the brushite lattice. The role of magnesium as a stabilizing agent for synthesizing brushite under physiological conditions at room temperature has been studied. Chemical analysis, Fourier transform infrared spectroscopy and X-ray diffraction have also been conducted to validate the formation of magnesium substituted brushite under physiological conditions.

Synthesis of biphasic calcium phosphate containing nanostructured films by micro arc oxidation on magnesium alloy

Energy Technology Data Exchange (ETDEWEB)

Seyfoori, A., E-mail: klm.1985@yahoo.com [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, 16846-13114 Tehran (Iran, Islamic Republic of); National Cell Bank, Pasteur Institute of Iran, 13164 Tehran (Iran, Islamic Republic of); Mirdamadi, Sh.; Seyedraoufi, Z.S.; Khavandi, A. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, 16846-13114 Tehran (Iran, Islamic Republic of); Aliofkhazraei, M. [Department of Materials Engineering, Faculty of Engineering, Tarbiat Modares University, 14115-143 Tehran (Iran, Islamic Republic of)

2013-10-01

The present research reports the synthesis of an innovative nanostructured composite film containing biphasic calcium phosphate (BCP) by the micro arc oxidation (MAO) method on AZ31 magnesium alloy. Nanometric structure of the used hydroxyapatite powder and the coatings were characterized by means of transmission and field-emission scanning electron microscope, respectively. Electrochemical behaviors of the pure MAO and nanocomposite films were also evaluated by electrochemical impedance spectroscopy and potentiodynamic polarization tests in simulated body fluid (SBF) environment. The results showed higher corrosion resistance of nanocomposite film compared to pure MAO coating, which was related to the blocking feature of the nanoparticles from the diffusing of the corrosive medium through the substrate. In addition, by immersing the specimens in simulated body fluid, greater apatite forming ability of the nanocomposite coating was proved. - Highlights: • Synthesis of innovative biphasic calcium phosphate containing nanostructured films via micro arc oxidation. • Nanocomposite film has lower degradation rate than pure MAO film. • Greater apatite forming ability for nanocomposite coating compared with pure MAO film is obtained.

Synthesis of biphasic calcium phosphate containing nanostructured films by micro arc oxidation on magnesium alloy

International Nuclear Information System (INIS)

Seyfoori, A.; Mirdamadi, Sh.; Seyedraoufi, Z.S.; Khavandi, A.; Aliofkhazraei, M.

2013-01-01

The present research reports the synthesis of an innovative nanostructured composite film containing biphasic calcium phosphate (BCP) by the micro arc oxidation (MAO) method on AZ31 magnesium alloy. Nanometric structure of the used hydroxyapatite powder and the coatings were characterized by means of transmission and field-emission scanning electron microscope, respectively. Electrochemical behaviors of the pure MAO and nanocomposite films were also evaluated by electrochemical impedance spectroscopy and potentiodynamic polarization tests in simulated body fluid (SBF) environment. The results showed higher corrosion resistance of nanocomposite film compared to pure MAO coating, which was related to the blocking feature of the nanoparticles from the diffusing of the corrosive medium through the substrate. In addition, by immersing the specimens in simulated body fluid, greater apatite forming ability of the nanocomposite coating was proved. - Highlights: • Synthesis of innovative biphasic calcium phosphate containing nanostructured films via micro arc oxidation. • Nanocomposite film has lower degradation rate than pure MAO film. • Greater apatite forming ability for nanocomposite coating compared with pure MAO film is obtained

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

Science.gov (United States)

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. Copyright © 2012 Elsevier B.V. All rights reserved.

Systems of amonium polyborates - monoammonium phosphate -water at 25 deg C

International Nuclear Information System (INIS)

Skvortsov, V.G.; Sadetdinov, Sh.V.; Polenov, A.D.; Mikhajlov, V.I.

1992-01-01

It is established by solubility and refractometry methods at 25 deg C that systems of ammonium tetraborate (pentaborate) monoammonium phosphate-water refer to sumple eutonic type. The ammonium borates and monoammoniumphosphate exert salting effect over each other. It is found that phosphate borate compositions on the basis of ammonium salts are characterized by lower inhibitor properties as compared to sodium salts

Microwave assisted coating of bioactive amorphous magnesium phosphate (AMP) on polyetheretherketone (PEEK).

Science.gov (United States)

Ren, Yufu; Sikder, Prabaha; Lin, Boren; Bhaduri, Sarit B

2018-04-01

Polyetheretherketone (PEEK) with great thermal and chemical stability, desirable mechanical properties and promising biocompatibility is being widely used as orthopedic and dental implant materials. However, the bioinert surface of PEEK can hinder direct osseointegration between the host tissue and PEEK based implants. The important signatures of this paper are as follows. First, we report for the formation of osseointegrable amorphous magnesium phosphate (AMP) coating on PEEK surface using microwave energy. Second, coatings consist of nano-sized AMP particles with a stacked thickness of 800nm. Third, coatings enhance bioactivity in-vitro and induce significantly high amount of bone-like apatite coating, when soaked in simulated body fluid (SBF). Fourth, the as-deposited AMP coatings present no cytotoxicity effects and are beneficial for cell adhesion at early stage. Finally, the high levels of expression of osteocalcin (OCN) in cells cultured on AMP coated PEEK samples indicate that AMP coatings can promote new bone formation and hence osseointegration. Copyright © 2017 Elsevier B.V. All rights reserved.

Corrosion resistance of multilayered magnesium phosphate/magnesium hydroxide film formed on magnesium alloy using steam-curing assisted chemical conversion method

International Nuclear Information System (INIS)

Ishizaki, Takahiro; Kudo, Ruriko; Omi, Takeshi; Teshima, Katsuya; Sonoda, Tsutomu; Shigematsu, Ichinori; Sakamoto, Michiru

2012-01-01

Anticorrosive multilayered films were successfully prepared on magnesium alloy AZ31 by chemical conversion treatment, followed by steam curing treatment. The crystal structures, chemical composition, surface morphologies, chemical bonding states of the film was characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscope (FE-SEM) measurements. All the films had thicknesses of ranging from 24 to 32 μm. The film had two layers that were composed of crystalline NH 4 MgPO 4 ·H 2 O, Mg 2 PO 4 OH·3H 2 O, Mg(OH) 2 and amorphous MgO. The outer layers include magnesium, oxygen, and phosphorous, and the inner layers include magnesium and oxygen. The corrosion resistant performances of the multilayered films in 5 wt% NaCl aqueous solution were investigated by electrochemical and gravimetric measurements. The potentiodynamic polarization curves revealed that the corrosion current density (j corr ) of all the film coated magnesium alloys decreased by more than four orders of magnitude as compared to that of the bare magnesium alloy, indicating that all the films had an inhibiting effect of corrosion reaction. Gravimetric measurements showed that the average corrosion rates obtained from the weight loss rates were estimated to be in the ranges of ca. 0.085–0.129 mm/y. American Society for Testing and Materials (ASTM) standard D 3359-02 cross cut tape test revealed that the adhesion of our anticorrosive multilayered film to the magnesium alloy surface was very good.

Characterisation of magnesium potassium phosphate cements blended with fly ash and ground granulated blast furnace slag

Energy Technology Data Exchange (ETDEWEB)

Gardner, Laura J.; Bernal, Susan A.; Walling, Samuel A.; Corkhill, Claire L.; Provis, John L.; Hyatt, Neil C., E-mail: n.c.hyatt@sheffield.ac.uk

2015-08-15

Magnesium potassium phosphate cements (MKPCs), blended with 50 wt.% fly ash (FA) or ground granulated blast furnace slag (GBFS) to reduce heat evolution, water demand and cost, were assessed using compressive strength, X-ray diffraction (XRD), scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) spectroscopy on {sup 25}Mg, {sup 27}Al, {sup 29}Si, {sup 31}P and {sup 39}K nuclei. We present the first definitive evidence that dissolution of the glassy aluminosilicate phases of both FA and GBFS occurred under the pH conditions of MKPC. In addition to the main binder phase, struvite-K, an amorphous orthophosphate phase was detected in FA/MKPC and GBFS/MKPC systems. It was postulated that an aluminium phosphate phase was formed, however, no significant Al–O–P interactions were identified. High-field NMR analysis of the GBFS/MKPC system indicated the potential formation of a potassium-aluminosilicate phase. This study demonstrates the need for further research on these binders, as both FA and GBFS are generally regarded as inert fillers within MKPC.

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

Science.gov (United States)

Elmore, Amy R

2005-01-01

L-Ascorbic Acid, Calcium Ascorbate, Magnesium Ascorbate, Magnesium Ascorbyl Phosphate, Sodium Ascorbate, and Sodium Ascorbyl Phosphate function in cosmetic formulations primarily as antioxidants. Ascorbic Acid is commonly called Vitamin C. Ascorbic Acid is used as an antioxidant and pH adjuster in a large variety of cosmetic formulations, over 3/4 of which were hair dyes and colors at concentrations between 0.3% and 0.6%. For other uses, the reported concentrations were either very low (cosmetics, but are not currently used. Sodium Ascorbyl Phosphate functions as an antioxidant in cosmetic products and is used at concentrations ranging from 0.01% to 3%. Magnesium Ascorbyl Phosphate functions as an antioxidant in cosmetics and was reported being used at concentrations from 0.001% to 3%. Sodium Ascorbate also functions as an antioxidant in cosmetics at concentrations from 0.0003% to 0.3%. Related ingredients (Ascorbyl Palmitate, Ascorbyl Dipalmitate, Ascorbyl Stearate, Erythorbic Acid, and Sodium Erythorbate) have been previously reviewed by the Cosmetic Ingredient Review (CIR) Expert Panel and found "to be safe for use as cosmetic ingredients in the present practices of good use." Ascorbic Acid is a generally recognized as safe (GRAS) substance for use as a chemical preservative in foods and as a nutrient and/or dietary supplement. Calcium Ascorbate and Sodium Ascorbate are listed as GRAS substances for use as chemical preservatives. L-Ascorbic Acid is readily and reversibly oxidized to L-dehydroascorbic acid and both forms exist in equilibrium in the body. Permeation rates of Ascorbic Acid through whole and stripped mouse skin were 3.43 +/- 0.74 microg/cm(2)/h and 33.2 +/- 5.2 microg/cm(2)/h. Acute oral and parenteral studies in mice, rats, rabbits, guinea pigs, dogs, and cats demonstrated little toxicity. Ascorbic Acid and Sodium Ascorbate acted as a nitrosation inhibitor in several food and cosmetic product studies. No compound-related clinical signs or gross or

Influence of aggressive ions on the degradation behavior of biomedical magnesium alloy in physiological environment.

Science.gov (United States)

Xin, Yunchang; Huo, Kaifu; Tao, Hu; Tang, Guoyi; Chu, Paul K

2008-11-01

Various electrochemical approaches, including potentiodynamic polarization, open circuit potential evolution and electrochemical impedance spectroscopy (EIS), are employed to investigate the degradation behavior of biomedical magnesium alloy under the influence of aggressive ions, such as chloride, phosphate, carbonate and sulfate, in a physiological environment. The synergetic effects and mutual influence of these ions on the degradation behavior of Mg are revealed. Our results demonstrate that chloride ions can induce porous pitting corrosion. In the presence of phosphates, the corrosion rate decreases and the formation of pitting corrosion is significantly delayed due to precipitation of magnesium phosphate. Hydrogen carbonate ions are observed to stimulate the corrosion of magnesium alloy during the early immersion stage but they can also induce rapid passivation on the surface. This surface passivation behavior mainly results from the fast precipitation of magnesium carbonate in the corrosion product layer that can subsequently inhibit pitting corrosion completely. Sulfate ions are also found to stimulate magnesium dissolution. These results improve our understanding on the degradation mechanism of surgical magnesium in the physiological environment.

Zirconium phosphate waste forms for low-temperature stabilization of cesium-137-containing waste streams

International Nuclear Information System (INIS)

Singh, D.; Wagh, A.S.; Tlustochowicz.

1996-04-01

Novel chemically bonded phosphate ceramics are being developed and fabricated for low-temperature stabilization and solidification of waste streams that are not amenable to conventional high-temperature stabilization processes because volatiles are present in the wastes. A composite of zirconium-magnesium phosphate has been developed and shown to stabilize ash waste contaminated with a radioactive surrogate of 137 Cs. Excellent retainment of cesium in the phosphate matrix system was observed in Toxicity Characteristic Leaching Procedure tests. This was attributed to the capture of cesium in the layered zirconium phosphate structure by intercalation ion-exchange reaction. But because zirconium phosphate has low strength, a novel zirconium/magnesium phosphate composite waste form system was developed. The performance of these final waste forms, as indicated by compression strength and durability in aqueous environments, satisfy the regulatory criteria. Test results indicate that zirconium-magnesium-phosphate-based final waste forms present a viable technology for treatment and solidification of cesium-contaminated wastes

Effect of pre-calving zeolite, magnesium and phosphorus supplemention on periparturient serum mineral concentrations

DEFF Research Database (Denmark)

Pallesen, Anders; Pallesen, Flemming; Jørgensen, Rolf Jess

2008-01-01

The objective of this study was to test whether supplementing dry cow rations with phosphorus (P) and magnesium (Mg) would interfere with the beneficial effect of zeolite supplementation on the periparturient blood calcium (Ca) concentration in dairy cattle. Three groups (A-C) of 10 Danish Jersey...... cows were each given the following daily supplements from 2 weeks before the expected date of calving until actual calving: group A: zeolite, monoammonium phosphate, standard dry cow mineral and vitamin mix, containing 61g magnesium phosphate; group B: zeolite, standard mineral and vitamin mix without...... the magnesium phosphate and group C: standard mineral and vitamin mix, monoammonium phosphate. All cows in group B had an apparently less variable serum calcium concentration around calving with no cases of milk fever and no subclinical hypocalcaemia or hypomagnesaemia recorded. In contrast, a parturient drop...

Characterization and mechanical properties of coatings on magnesium by micro arc oxidation

International Nuclear Information System (INIS)

Durdu, Salih; Usta, Metin

2012-01-01

Highlights: ► The commercial pure magnesium was coated by MAO in sodium silicate and sodium phosphate. ► Coatings produced in the phosphate electrolyte are thicker than ones in the silicate electrolyte. ► Coatings in the silicate electrolyte are harder than ones in the phosphate electrolyte. ► Adhesion strength of coatings increases with increasing coating thickness. ► The wear resistance of the coated commercial pure magnesium is improved. - Abstracts: The commercial pure magnesium was coated by micro arc oxidation method in different aqueous solution, containing sodium silicate and sodium phosphate. Micro arc oxidation process was carried out at 0.060 A/cm 2 , 0.085 A/cm 2 and 0.140 A/cm 2 current densities for 30 min. The thickness, phase composition, morphology, hardness, adhesion strength and wear resistance of coatings were analyzed by eddy current, X-ray diffraction (XRD), scanning electron microscope (SEM), micro hardness tester, scratch tester and ball-on disk tribometer, respectively. The average thicknesses of the micro arc oxidized coatings ranged from 27 to 48 μm for sodium silicate solution and from 45 to 75 μm for sodium phosphate solution. The dominant phases formed on the pure magnesium were found to be a mixture of spinel Mg 2 SiO 4 (Forsterite) and MgO (Periclase) for sodium silicate solution and Mg 3 (PO 4 ) 2 (Farringtonite) and MgO (Periclase) for sodium phosphate solution. The average hardnesses of the micro arc oxidized coatings were between 260 HV and 470 HV for sodium silicate solution and between 175 HV and 260 HV for sodium phosphate solution. Adhesion strengths and wear resistances of coatings produced in sodium silicate solution were higher than those of the ones in sodium phosphate solution due to high hardness of coatings produced in sodium silicate solution.

Solid-state reaction kinetics and optical studies of cadmium doped magnesium hydrogen phosphate crystals

Science.gov (United States)

Verma, Madhu; Gupta, Rashmi; Singh, Harjinder; Bamzai, K. K.

2018-04-01

The growth of cadmium doped magnesium hydrogen phosphate was successfully carried out by using room temperature solution technique i.e., gel encapsulation technique. Grown crystals were confirmed by single crystal X-ray diffraction (XRD). The structure of the grown crystal belongs to orthorhombic crystal system and crystallizes in centrosymmetric space group. Kinetics of the decomposition of the grown crystals were studied by non-isothermal analysis. Thermo gravimetric / differential thermo analytical (TG/DTA) studies revealed that the grown crystal is stable upto 119 °C. The various steps involved in the thermal decomposition of the material have been analysed using Horowitz-Metzger, Coats-Redfern and Piloyan-Novikova equations for evaluating various kinetic parameters. The optical studies shows that the grown crystals possess wide transmittance in the visible region and significant optical band gap of 5.5ev with cut off wavelength of 260 nm.

On the capacity to the complexing of alkaline earth metal and magnesium chromates

International Nuclear Information System (INIS)

Orekhov, O.L.

1978-01-01

Considered is the capacity to the complexing of magnesium chromates and alkaline earth metal chromates with ammonium chromates in aqueous solutions. It has been established that the complexing of alkaline earth metal and magnesium chromates is effected by a nature of initial salts as well as their solubilities and the presence of crystallization water. Capacity of magnesium ions and alkaline rare earth metals to the complexing decreases in a series of Mg-Ca-Sr-Ba. Ca complexes exceed magnesium derivatives in respect of stability

A magnesium based phosphate binder reduces vascular calcification without affecting bone in chronic renal failure rats.

Directory of Open Access Journals (Sweden)

Ellen Neven

Full Text Available The alternative phosphate binder calcium acetate/magnesium carbonate (CaMg effectively reduces hyperphosphatemia, the most important inducer of vascular calcification, in chronic renal failure (CRF. In this study, the effect of low dose CaMg on vascular calcification and possible effects of CaMg on bone turnover, a persistent clinical controversy, were evaluated in chronic renal failure rats. Adenine-induced CRF rats were treated daily with 185 mg/kg CaMg or vehicle for 5 weeks. The aortic calcium content and area% calcification were measured to evaluate the effect of CaMg. To study the effect of CaMg on bone remodeling, rats underwent 5/6th nephrectomy combined with either a normal phosphorus diet or a high phosphorus diet to differentiate between possible bone effects resulting from either CaMg-induced phosphate deficiency or a direct effect of Mg. Vehicle or CaMg was administered at doses of 185 and 375 mg/kg/day for 8 weeks. Bone histomorphometry was performed. Aortic calcium content was significantly reduced by 185 mg/kg/day CaMg. CaMg ameliorated features of hyperparathyroid bone disease. In CRF rats on a normal phosphorus diet, the highest CaMg dose caused an increase in osteoid area due to phosphate depletion. The high phosphorus diet combined with the highest CaMg dose prevented the phosphate depletion and thus the rise in osteoid area. CaMg had no effect on osteoblast/osteoclast or dynamic bone parameters, and did not alter bone Mg levels. CaMg at doses that reduce vascular calcification did not show any harmful effect on bone turnover.

Evolution of the magnesium incorporated amorphous calcium phosphate to nano-crystallized hydroxyapatite in alkaline solution

Science.gov (United States)

Zhang, Xiao-Juan; Lin, Dong-Yang; Yan, Xiao-Hui; Wang, Xiao-Xiang

2011-12-01

A homogeneous amorphous calcium phosphate (ACP) coating containing magnesium was achieved on titanium substrates by electrochemical deposition (ECD). Its amorphous structure is confirmed by transmission electron microscope (TEM) together with grazing reflection absorption infrared spectroscopy (IR) spectrometer. In the images of high-resolution transmission electron microscope (HRTEM), the ACP spheres are assembled by nano-particles with the diameter of 5-10 nm. In the alkaline environment, nucleation of hydroxyapatite (HAP) occurs on the surfaces of ACP spheres. By consuming the Ca and PO 4 ions inside the ACP spheres, the HAP nuclei grow outward. Confirmed by TEM, the ACP spheres converse to hollow HAP spheres composed of HAP nano-needles. The coating is finally constructed by the HAP nano-needles, which are themselves aggregated by numerous nano-particles.

Novel Nonflammable Electrolytes for Secondary Magnesium Batteries and High Voltage Electrolytes for Electrochemcial Supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Dixon, Brian

2008-12-30

Magnesium has been used successfully in primary batteries, but its use in rechargeable cells has been stymied by the lack of suitable non-aqueous electrolyte that can conduct Mg+2 species, combined with poor stripping and plating properties. The development of a suitable cathode material for rechargeable magnesium batteries has also been a roadblock, but a nonflammable electrolyte is key. Likewise, the development of safe high voltage electrochemical supercapaitors has been stymied by the use of flammable solvents in the liquid electrolyte; to wit, acetonitrile. The purpose of the research conducted in this effort was to identify useful compositions of magnesium salts and polyphosphate solvents that would enable magnesium ions to be cycled within a secondary battery design. The polyphosphate solvents would provide the solvent for the magnesium salts while preventing the electrolyte from being flammable. This would enable these novel electrolytes to be considered as an alternative to THF-based electrolytes. In addition, we explored several of these solvents together with lithium slats for use as high voltage electrolytes for carbon-based electrochemical supercapacitors. The research was successful in that: 1) Magnesium imide dissolved in a phosphate ester solvent that contains a halogented phosphate ester appears to be the preferred electrolyte for a rechargeable Mg cell. 2) A combination of B-doped CNTs and vanadium phosphate appear to be the cathode of choice for a rechargeable Mg cell by virtue of higher voltage and better reversibility. 3) Magnesium alloys appear to perform better than pure magnesium when used in combination with the novel polyphosphate electrolytes. Also, this effort has established that Phoenix Innovation's family of phosphonate/phosphate electrolytes together with specific lithium slats can be used in supercapacitor systems at voltages of greater than 10V.

Electrochemical corrosion behaviour of plasma electrolytic oxidation coatings on AM50 magnesium alloy formed in silicate and phosphate based electrolytes

International Nuclear Information System (INIS)

Liang, J.; Srinivasan, P. Bala; Blawert, C.; Stoermer, M.; Dietzel, W.

2009-01-01

PEO coatings were produced on AM50 magnesium alloy by plasma electrolytic oxidation process in silicate and phosphate based electrolytes using a pulsed DC power source. The microstructure and composition of the PEO coatings were analyzed by scanning electron microscopy (SEM) and X-ray Diffraction (XRD). The corrosion resistance of the PEO coatings was evaluated using open circuit potential (OCP) measurements, potentiodynamic polarisation tests and electrochemical impedance spectroscopy (EIS) in 0.1 M NaCl solution. It was found that the electrolyte composition has a significant effect on the coating evolution and on the resulting coating characteristics, such as microstructure, composition, coating thickness, roughness and thus on the corrosion behaviour. The corrosion resistance of the PEO coating formed in silicate electrolyte was found to be superior to that formed in phosphate electrolyte in both the short-term and long-term electrochemical corrosion tests.

Magnesium Potassium Phosphate Compound for Immobilization of Radioactive Waste Containing Actinide and Rare Earth Elements

Directory of Open Access Journals (Sweden)

Sergey E. Vinokurov

2018-06-01

Full Text Available The problem of effective immobilization of liquid radioactive waste (LRW is key to the successful development of nuclear energy. The possibility of using the magnesium potassium phosphate (MKP compound for LRW immobilization on the example of nitric acid solutions containing actinides and rare earth elements (REE, including high level waste (HLW surrogate solution, is considered in the research work. Under the study of phase composition and structure of the MKP compounds that is obtained by the XRD and SEM methods, it was established that the compounds are composed of crystalline phases—analogues of natural phosphate minerals (struvite, metaankoleite. The hydrolytic stability of the compounds was determined according to the semi-dynamic test GOST R 52126-2003. Low leaching rates of radionuclides from the compound are established, including a differential leaching rate of 239Pu and 241Am—3.5 × 10−7 and 5.3 × 10−7 g/(cm2∙day. As a result of the research work, it was concluded that the MKP compound is promising for LRW immobilization and can become an alternative material combining the advantages of easy implementation of the technology, like cementation and the high physical and chemical stability corresponding to a glass-like compound.

Phosphates (V) recovery from phosphorus mineral fertilizers industry wastewater by continuous struvite reaction crystallization process.

Science.gov (United States)

Hutnik, Nina; Kozik, Anna; Mazienczuk, Agata; Piotrowski, Krzysztof; Wierzbowska, Boguslawa; Matynia, Andrzej

2013-07-01

Continuous DT MSMPR (Draft Tube Mixed Suspension Mixed Product Removal) crystallizer was provided with typical wastewater from phosphorus mineral fertilizers industry (pH < 4, 0.445 mass % of PO4(3-), inorganic impurities presence), dissolved substrates (magnesium and ammonium chlorides) and solution alkalising the environment of struvite MgNH4PO4·6H2O reaction crystallization process. Research ran in constant temperature 298 K assuming stoichiometric proportions of substrates or 20% excess of magnesium ions. Influence of pH (8.5-10) and mean residence time (900-3600 s) on product size distribution, its chemical composition, crystals shape, size-homogeneity and process kinetics was identified. Crystals of mean size ca. 25-37 μm and homogeneity CV 70-83% were produced. The largest crystals, of acceptable homogeneity, were produced using 20% excess of magnesium ions, pH 9 and mean residence time 3600 s. Under these conditions nucleation rate did not exceed 9 × 10(7) 1/(s m(3)) according to SIG (Size Independent Growth) MSMPR kinetic model. Linear crystal growth rate was 4.27 × 10(-9) m/s. Excess of magnesium ions influenced struvite reaction crystallization process yield advantageously. Concentration of phosphate(V) ions decreased from 0.445 to 9.2 × 10(-4) mass %. This can be regarded as a very good process result. In product crystals, besides main component - struvite, all impurities from wastewater were detected analytically. Copyright © 2013 Elsevier Ltd. All rights reserved.

Efficiency of ammonium nitrate phosphates of varying water-soluble phosphorus content for rice and succeeding maize crop on contrasting soil types. [/sup 32/P-labelled fertilizers

Energy Technology Data Exchange (ETDEWEB)

Bhujbal, B M; Mistry, K B [Bhabha Atomic Research Centre, Bombay (India). Biology and Agriculture Div.; Chapke, V G; Mutatkar, V K [Fertilizer Corp. of India Ltd., Bombay

1977-09-01

Efficiency of ammonium nitrate phosphates (ANP) containing 30 and 50 percent of water-soluble phosphorus (W.S.P.) vis-a-vis that of entirely water-soluble monoammonium orthophosphate (MAP) for rice and succeeding maize crop on phosphate responsive laterite, red sandy loam (Chalka) and calcareous black soils was examined in greenhouse experiments. Data on dry matter yield, uptake of phosphorus, utilization of applied fertilizer, 'Effective Rate of Application' and 'Relative Efficiency percent' at flowering stage of rice indicated no significant differences between ammonium nitrate phosphate (30 percent and 50 percent water-soluble ohosphorus) and monoammonium orthophosphate (MAP) on laterits and natural red sandy loam soils. MAP was significantly superior to the two ANP fertilizers on calcareous black soil; no significant differences were observed between ANP (30 percent W.S.P.) and ANP (50 percent W.S.P.) on this soil. The succeeding maize crop grown up to flowering in the same pots indicated that the residual value of ANP (30 percent W.S.P.) was equal or superior to that of MAP on the laterits as well as calcareous black soil. No significant differences were detected between the residual values of the two water-solubility grades of ANP. Incubation under submerged conditions for periods upto 60 days showed that 0.5 M NaHCO/sub 3/ (pH 8.5) extractable phosphorus (plant-available phosphate) in the ANP (30 percent W.S.P.) treatment was, in general, equal to those in the MAP treatments in the laterite and red sandy loam but was significantly lower in the calcareous black soil. No marked differences were observed between the effects of the two ANP fertilizers.

Removal of ammonia from landfill leachate by struvite precipitation with the use of low-cost phosphate and magnesium sources.

Science.gov (United States)

Huang, Haiming; Xiao, Dean; Zhang, Qingrui; Ding, Li

2014-12-01

This paper presents a study concerning ammonia removal from landfill leachate by struvite precipitation with the use of waste phosphoric acid as the phosphate source. The results indicated that the Al(3+) ions present in the waste phosphoric acid significantly affected the struvite precipitation, and a removal ratio of ammonia close to that of pure phosphate salts could be achieved. Nevertheless, large amounts of NaOH were necessary to neutralize the H(+) present in the waste phosphoric acid. To overcome this problem, a low-cost magnesium source was proposed to be used as well as an alkali reagent in the struvite precipitation. The ammonia removal ratios were found to be 83%, with a remaining phosphate of 56 mg/L, by dosing the low-cost MgO in the Mg:N:P molar ratio of 3:1:1. An economic analysis showed that using waste phosphoric acid plus the low-cost MgO could save chemical costs by 68% compared with the use of pure chemicals. Post-treatment employment of a biological anaerobic filter process demonstrated that the high concentration of Mg(2+) remaining in the effluent of the struvite precipitation has no inhibitory effect on the performance of the biological treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Limnology and cyanobacterial diversity of high altitude lakes of ...

Indian Academy of Sciences (India)

2014-07-08

Jul 8, 2014 ... magnesium, total phosphate, ammonium nitrogen and nitrate nitrogen by standard ...... WF and Quesada A 2007 Community structure and physiolog- .... in alpine region, new horizons in environmental economics. (eds) KW ...

Investigation of boron extraction process with aid magnesium hydroxide from mother liquor of boron production

International Nuclear Information System (INIS)

Balapanova, B.S.; Zhajmina, R.E.; Serazetdinov, D.Z.

1988-01-01

Conditions of boron - magnesium concentrate preparation from mother liquor by coprecipitation of borate - ions by magnesium hydroxide are investigated. It is shown that boron - magnesium concentrate and products of its heat treatment at 100 - 500 deg C in water are dissolved partially, and in ammonium citrate - practically completely. Suppositions are made on the composition of the product prepared, on the the structure of its crystal lattice and the processes taking place in it during heat treatment. The conclusion is made on the perspectiveness of processing of mother liquor of boron industry for boron - magnesium concentrate

Rapid analysis of fertilizers by the direct-reading thermometric method.

Science.gov (United States)

Sajó, I; Sipos, B

1972-05-01

The authors have developed rapid methods for the determination of the main components of fertilizers, namely phosphate, potassium and nitrogen fixed in various forms. In the absence of magnesium ions phosphate is precipitated with magnesia mixture; in the presence of magnesium ions ammonium phosphomolybdate is precipitated and the excess of molybdate is reacted with hydrogen peroxide. Potassium is determined by precipitation with silico-fluoride. For nitrogen fixed as ammonium salts the ammonium ions are condensed in a basic solution with formalin to hexamethylenetetramine; for nitrogen fixed as carbamide the latter is decomposed with sodium nitrite; for nitrogen fixed as nitrate the latter is reduced with titanium(III). In each case the temperature change of the test solution is measured. Practically all essential components of fertilizers may be determined by direct-reading thermometry; with this method and special apparatus the time of analysis is reduced to at most about 15 min for any determination.

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

Science.gov (United States)

Hiromoto, Sachiko; Yamazaki, Tomohiko

2017-12-01

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.

The Effect of Adding Corrosion Inhibitors into an Electroless Nickel Plating Bath for Magnesium Alloys

Science.gov (United States)

Hu, Rong; Su, Yongyao; Liu, Hongdong; Cheng, Jiang; Yang, Xin; Shao, Zhongcai

2016-10-01

In this work, corrosion inhibitors were added into an electroless nickel plating bath to realize nickel-phosphorus (Ni-P) coating deposition on magnesium alloy directly. The performance of five corrosion inhibitors was evaluated by inhibition efficiency. The results showed that only ammonium hydrogen fluoride (NH4HF2) and ammonium molybdate ((NH4)2MoO4) could be used as corrosion inhibitors for magnesium alloy in the bath. Moreover, compounding NH4HF2 and (NH4)2MoO4, the optimal concentrations were both at 1.5 ~ 2%. The deposition process of Ni-P coating was observed by using a scanning electron microscope (SEM). It showed corrosion inhibitors inhibited undesired dissolution of magnesium substrate during the electroless plating process. In addition, SEM observation indicated that the corrosion inhibition reaction and the Ni2+ replacement reaction were competitive at the initial deposition time. Both electrochemical analysis and thermal shock test revealed that the Ni-P coating exhibited excellent corrosion resistance and adhesion properties in protecting the magnesium alloy.

Magnesium Inhibits Wnt/β-Catenin Activity and Reverses the Osteogenic Transformation of Vascular Smooth Muscle Cells

Science.gov (United States)

Montes de Oca, Addy; Guerrero, Fatima; Martinez-Moreno, Julio M.; Madueño, Juan A.; Herencia, Carmen; Peralta, Alan; Almaden, Yolanda; Lopez, Ignacio; Aguilera-Tejero, Escolastico; Gundlach, Kristina; Büchel, Janine; Peter, Mirjam E.; Passlick-Deetjen, Jutta; Rodriguez, Mariano; Muñoz-Castañeda, Juan R.

2014-01-01

Magnesium reduces vascular smooth muscle cell (VSMC) calcification in vitro but the mechanism has not been revealed so far. This work used only slightly increased magnesium levels and aimed at determining: a) whether inhibition of magnesium transport into the cell influences VSMC calcification, b) whether Wnt/β-catenin signaling, a key mediator of osteogenic differentiation, is modified by magnesium and c) whether magnesium can influence already established vascular calcification. Human VSMC incubated with high phosphate (3.3 mM) and moderately elevated magnesium (1.4 mM) significantly reduced VSMC calcification and expression of the osteogenic transcription factors Cbfa-1 and osterix, and up-regulated expression of the natural calcification inhibitors matrix Gla protein (MGP) and osteoprotegerin (OPG). The protective effects of magnesium on calcification and expression of osteogenic markers were no longer observed in VSMC cultured with an inhibitor of cellular magnesium transport (2-aminoethoxy-diphenylborate [2-APB]). High phosphate induced activation of Wnt/β-catenin pathway as demonstrated by the translocation of β-catenin into the nucleus, increased expression of the frizzled-3 gene, and downregulation of Dkk-1 gene, a specific antagonist of the Wnt/β-catenin signaling pathway. The addition of magnesium however inhibited phosphate-induced activation of Wnt/β-catenin signaling pathway. Furthermore, TRPM7 silencing using siRNA resulted in activation of Wnt/β-catenin signaling pathway. Additional experiments were performed to test the ability of magnesium to halt the progression of already established VSMC calcification in vitro. The delayed addition of magnesium decreased calcium content, down-regulated Cbfa-1 and osterix and up-regulated MGP and OPG, when compared with a control group. This effect was not observed when 2-APB was added. In conclusion, magnesium transport through the cell membrane is important to inhibit VSMC calcification in vitro

Preliminary research on a novel bioactive silicon doped calcium phosphate coating on AZ31 magnesium alloy via electrodeposition

Energy Technology Data Exchange (ETDEWEB)

Qiu, Xun [Department of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Institute of Metal Research, Chinese Academy of Science, Shenyang 110016 (China); Wan, Peng, E-mail: pwan@imr.ac.cn [Institute of Metal Research, Chinese Academy of Science, Shenyang 110016 (China); Tan, LiLi [Institute of Metal Research, Chinese Academy of Science, Shenyang 110016 (China); Fan, XinMin [Department of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Yang, Ke [Institute of Metal Research, Chinese Academy of Science, Shenyang 110016 (China)

2014-03-01

A silicon doped calcium phosphate coating was obtained successfully on AZ31 alloy substrate via pulse electrodeposition. A novel dual-layer structure was observed with a porous lamellar-like and outer block-like apatite layer. In vitro immersion tests were adopted in simulated body fluid within 28 days of immersion. Slow degradation rate obtained from weight loss was observed for the Si-doped Ca–P coating, which was also consistent with the results of electrochemical experiments showing an enhanced corrosion resistance for the coating. Further formation of an apatite-like layer on the surface after immersion proved better integrity and biomineralization performance of the coating. Biological characterization was carried out for viability, proliferation and differentiation of MG63 osteoblast-like cells. The coating showed a good cell growth and an enhanced cell proliferation. Moreover, an increased activity of osteogenic marker ALP was found. All the results demonstrated that the Si-doped calcium phosphate was perspective to be used as a coating for magnesium alloy implants to control the degradation rate and enhance the bioactivity, which would facilitate the rapidity of bone tissue repair. - Highlights: • A Si-doped calcium phosphate coating was achieved via pulse ED on AZ31 alloy. • The coating was composed of a porous lamellar-like layer and outer block-like apatite. • The coating showed slow degradation rate and better biomineralization property. • The coating improved cell proliferation and activity of osteogenic marker ALP.

Preliminary research on a novel bioactive silicon doped calcium phosphate coating on AZ31 magnesium alloy via electrodeposition

International Nuclear Information System (INIS)

Qiu, Xun; Wan, Peng; Tan, LiLi; Fan, XinMin; Yang, Ke

2014-01-01

A silicon doped calcium phosphate coating was obtained successfully on AZ31 alloy substrate via pulse electrodeposition. A novel dual-layer structure was observed with a porous lamellar-like and outer block-like apatite layer. In vitro immersion tests were adopted in simulated body fluid within 28 days of immersion. Slow degradation rate obtained from weight loss was observed for the Si-doped Ca–P coating, which was also consistent with the results of electrochemical experiments showing an enhanced corrosion resistance for the coating. Further formation of an apatite-like layer on the surface after immersion proved better integrity and biomineralization performance of the coating. Biological characterization was carried out for viability, proliferation and differentiation of MG63 osteoblast-like cells. The coating showed a good cell growth and an enhanced cell proliferation. Moreover, an increased activity of osteogenic marker ALP was found. All the results demonstrated that the Si-doped calcium phosphate was perspective to be used as a coating for magnesium alloy implants to control the degradation rate and enhance the bioactivity, which would facilitate the rapidity of bone tissue repair. - Highlights: • A Si-doped calcium phosphate coating was achieved via pulse ED on AZ31 alloy. • The coating was composed of a porous lamellar-like layer and outer block-like apatite. • The coating showed slow degradation rate and better biomineralization property. • The coating improved cell proliferation and activity of osteogenic marker ALP

Stone risk after bladder substitution with the ileal-urethral Kock reservoir

DEFF Research Database (Denmark)

Osther, P J; Poulsen, A L; Steven, K

2000-01-01

: The participants were 23 male patients who had undergone bladder substitution with the ileal-urethral Kock reservoir and 25 healthy men. All subjects had sterile urine at the time of urine collection. Concentrations of calcium, magnesium, phosphorus, creatinine, citrate, oxalate, and ammonia in 24-h urine samples...... were measured. Estimates of ion activity products of calcium oxalate (CaOx), calcium phosphate (CaP), brushite (Bru), and magnesium ammonium phosphate (MAP) in urine were calculated according to Tiselius. RESULTS: There was no significant difference in 24-h urinary volume between patients...

Dibasic Ammonium Phosphate Application Enhances Aromatic Compound Concentration in Bog Bilberry Syrup Wine

Directory of Open Access Journals (Sweden)

Shao-Yang Wang

2016-12-01

Full Text Available A nitrogen deficiency always causes bog bilberry syrup wine to have a poor sensory feature. This study investigated the effect of nitrogen source addition on volatile compounds during bog bilberry syrup wine fermentation. The syrup was supplemented with 60, 90, 120 or 150 mg/L dibasic ammonium phosphate (DAP before fermentation. Results showed that an increase of DAP amounts accelerated fermentation rate, increased alcohol content, and decreased sugar level. Total phenol and total flavonoid content were also enhanced with the increase of DAP amounts. A total of 91 volatile compounds were detected in the wine and their concentrations were significantly enhanced with the increase of DAP. Ethyl acetate, isoamyl acetate, phenethyl acetate, ethyl butanoate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, isobutanol, isoamyl alcohol, levo-2,3-butanediol, 2-phenylethanol, meso-2,3-butanediol, isobutyric acid, hexanoic acid, and octanoic acid exhibited a significant increase of their odor activity value (OAV with the increase of DAP amounts. Bog bilberry syrup wine possessed fruity, fatty, and caramel flavors as its major aroma, whereas a balsamic note was the least present. The increase of DAP amounts significantly improved the global aroma attributes, thereby indicating that DAP supplementation could promote wine fermentation performance and enhance the sensory quality of bog bilberry syrup wine.

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

Directory of Open Access Journals (Sweden)

Enemark JMD

2001-06-01

Full Text Available 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.

Oxide growth on aluminium alloys in the presence of ammonium fluoborate

International Nuclear Information System (INIS)

Oliver, J.; Paterson, P.; Flavell, T.; Biddle, G.

1996-01-01

The aim of this study as to determine the mechanisms involved in using ammonium fluoborate as a reducing atmosphere when preheating a high magnesium content aluminium alloy. Rutherford Backscattering (RBS) has been the major technique used in the analysis of samples, it revealed significant reduction in both the diffusion of magnesium to the surface and the calculated oxide thickness in the presence of NH 4 BF 4 . At temperatures above 500 deg C in air, SEM images revealed depressions and voids due to incipient melting at various stages, around the grain boundaries. Grain boundaries effectively acted as pipes aiding the diffusion of magnesium to the surface. These results have been verified through compositional analysis with both RBS and auger electron spectroscopy (AES). Results from NH 4 BF 4 atmosphere preheat conditions showed significant improvements. It was verified experimentally that above 500 deg C , AA5182 alloys undergo incipient melting at the grain boundaries with magnesium diffusing through to the surface. 5 refs., 1 fig

Systems of amonium polyborates - monoammonium phosphate -water at 25 deg C. Sistemy poliboraty ammoniya - monoammonijfosfat - voda pri 25 grad S

Energy Technology Data Exchange (ETDEWEB)

Skvortsov, V G; Sadetdinov, Sh V; Polenov, A D; Mikhajlov, V I [Chuvashskij Gosudarstvennyj Pedagogicheskij Inst., Cheboksary (Russian Federation)

1992-11-01

It is established by solubility and refractometry methods at 25 deg C that systems of ammonium tetraborate (pentaborate) monoammonium phosphate-water refer to sumple eutonic type. The ammonium borates and monoammoniumphosphate exert salting effect over each other. It is found that phosphate borate compositions on the basis of ammonium salts are characterized by lower inhibitor properties as compared to sodium salts.

The formation of an organic coat and the release of corrosion microparticles from metallic magnesium implants.

Science.gov (United States)

Badar, Muhammad; Lünsdorf, Heinrich; Evertz, Florian; Rahim, Muhammad Imran; Glasmacher, Birgit; Hauser, Hansjörg; Mueller, Peter P

2013-07-01

Magnesium alloys have been proposed as prospective degradable implant materials. To elucidate the complex interactions between the corroding implants and the tissue, magnesium implants were analyzed in a mouse model and the response was compared to that induced by Ti and by the resorbable polymer polyglactin, respectively. One month after implantation, distinct traces of corrosion were apparent but the magnesium implants were still intact, whereas resorbable polymeric wound suture implants were already fragmented. Analysis of magnesium implants 2weeks after implantation by energy-dispersive X-ray spectroscopy indicated that magnesium, oxygen, calcium and phosphate were present at the implant surface. One month after implantation, the element composition of the outermost layer of the implant was indicative of tissue without detectable levels of magnesium, indicating a protective barrier function of this organic layer. In agreement with this notion, gene expression patterns in the surrounding tissue were highly similar for all implant materials investigated. However, high-resolution imaging using energy-filtered transmission electron microscopy revealed magnesium-containing microparticles in the tissue in the proximity of the implant. The release of such corrosion particles may contribute to the accumulation of calcium phosphate in the nearby tissue and to bone conductive activities of magnesium implants. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Parallel nano-assembling of a multifunctional GO/HapNP coating on ultrahigh-purity magnesium for biodegradable implants

Science.gov (United States)

Santos, C.; Piedade, C.; Uggowitzer, P. J.; Montemor, M. F.; Carmezim, M. J.

2015-08-01

This work reports the one-step fabrication of a novel coating on ultra high purity magnesium using a parallel nano assembling process. The multifunctional biodegradable surface was obtained by adding hydroxyapatite nanoparticles (HapNP) plus graphene oxide (GO). The coating was characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffractometer (XRD), micro-Raman spectroscopy. The thin phosphate coating (thickness of 1 μm) reveals a uniform coverage with cypress like structures. The incorporation of HapNP and GO promotes the hydrophilic behavior of the coating surface. The results revealed that the proposed coating can be used to tailor the surface properties such as wettability by adjusting the contents of HapNP and GO. The in vitro degradation rate of the coated magnesium suggests that the presence of HapNP and GO/HapNP in the phosphate coating decreased the current density compared to the single phosphate coating and uncoated magnesium. This study also reveals the HapNP/GO/phosphate coating induces apatite formation, showing suitable degradability that makes it a promising coating candidate for enhanced bone regeneration.

Magnesium-Molybate Compounds as Matrix for 99Mo/99mTc Generators

Directory of Open Access Journals (Sweden)

Fabiola Monroy-Guzman

2011-01-01

Full Text Available This work reports the preparation of a 99mTc generator based on conversion of 99Mo produced by neutron irradiation, into insoluble magnesium 99Mo-molybdates compounds as matrix. The effect of magnesium salt types and concentration, Mg:Mo molar ratios, pH of molybdate solutions, eluate volume as well as the addition order of molybdate and magnesium solutions’ influences on the final 99mTc were evaluated. Polymetalates and polymolybdates salts either crystallized or amorphous were obtained depending on the magnesium salt and Mg:Mo molar ratio used in matrix preparation. 99Mo/99mTc generator production based on magnesium-99Mo molybdate compounds allow reduction of preparation time and eliminates the use of specialized installations. The best generator performances were attained using matrices prepared from 0.1 mol/L MgCl2·6H2O solutions, ammonium molybdate solutions at pH 7 and at a Mg:Mo molar ratio of 1:1.

Oxide growth on aluminium alloys in the presence of ammonium fluoborate

Energy Technology Data Exchange (ETDEWEB)

Oliver, J; Paterson, P; Flavell, T [Royal Melbourne Inst. of Tech., VIC (Australia); Biddle, G [Alcoa Rolled Products (Australia)

1997-12-31

The aim of this study as to determine the mechanisms involved in using ammonium fluoborate as a reducing atmosphere when preheating a high magnesium content aluminium alloy. Rutherford Backscattering (RBS) has been the major technique used in the analysis of samples, it revealed significant reduction in both the diffusion of magnesium to the surface and the calculated oxide thickness in the presence of NH{sub 4}BF{sub 4}. At temperatures above 500 deg C in air, SEM images revealed depressions and voids due to incipient melting at various stages, around the grain boundaries. Grain boundaries effectively acted as pipes aiding the diffusion of magnesium to the surface. These results have been verified through compositional analysis with both RBS and auger electron spectroscopy (AES). Results from NH{sub 4}BF{sub 4} atmosphere preheat conditions showed significant improvements. It was verified experimentally that above 500 deg C , AA5182 alloys undergo incipient melting at the grain boundaries with magnesium diffusing through to the surface. 5 refs., 1 fig.

Oxide growth on aluminium alloys in the presence of ammonium fluoborate

Energy Technology Data Exchange (ETDEWEB)

Oliver, J.; Paterson, P.; Flavell, T. [Royal Melbourne Inst. of Tech., VIC (Australia); Biddle, G. [Alcoa Rolled Products (Australia)

1996-12-31

The aim of this study as to determine the mechanisms involved in using ammonium fluoborate as a reducing atmosphere when preheating a high magnesium content aluminium alloy. Rutherford Backscattering (RBS) has been the major technique used in the analysis of samples, it revealed significant reduction in both the diffusion of magnesium to the surface and the calculated oxide thickness in the presence of NH{sub 4}BF{sub 4}. At temperatures above 500 deg C in air, SEM images revealed depressions and voids due to incipient melting at various stages, around the grain boundaries. Grain boundaries effectively acted as pipes aiding the diffusion of magnesium to the surface. These results have been verified through compositional analysis with both RBS and auger electron spectroscopy (AES). Results from NH{sub 4}BF{sub 4} atmosphere preheat conditions showed significant improvements. It was verified experimentally that above 500 deg C , AA5182 alloys undergo incipient melting at the grain boundaries with magnesium diffusing through to the surface. 5 refs., 1 fig.

Nutrition and oxalate metabolism in cats

NARCIS (Netherlands)

Dijcker, J.C.

2013-01-01

Over the past 30 years, a progressive increase in calcium oxalate (CaOx) urolith prevalence is reported in cats and dogs diagnosed with urolithiasis. This increase in prevalence appears to have occurred since dietary modifications were introduced to address magnesium ammonium phosphate urolithiasis.

Influence of the environmental factors on the intensity of the oxygen, ammonium, and phosphate metabolism in the agar-containing seaweed Ahnfeltia tobuchiensis (Ahnfeltiales, Rhodophyta)

Science.gov (United States)

Cherbadgy, I. I.; Sabitova, L. I.

2011-02-01

A complex study of the influence of various environmental factors on the rate of the oxygen (MO 2), ammonium (MNH 4), and phosphate (MPO 4) metabolism in Ahnfeltia tobuchiensis has been carried out in situ in the Izmena Bay of Kunashir Island. The following environmental factors have been included into the investigation: the photosynthetically active radiation (PAR); the ammonium (NH4); the phosphate (PO4); and the tissue content of carbon (C), nitrogen (N), phosphorus (P), and chlorophyll a (Chl). The population of agar-containing seaweed A. tobuchiensis forms a layer with a thickness up to 0.5 m, which occupies about 23.3 km2; the population's biomass is equal to 125000 tons. The quantitative assessment of the organic matter production and nutrient consumption during the oxygen metabolism (MO 2) has been carried out for the whole population. It has been shown that the daily rate depends on the PAR intensity, the seawater concentrations of PO4 and NH4, and the tissue content of N and P ( r 2 = 0.78, p < 0.001). The daily NH4 consumption averages 0.21 μmol/(gDW h) and depends on the NH4 and O2 concentrations in the seawater and on the C and Chl a content in the algal tissues ( r 2 = 0.64, p < 0.001). The daily PO4 consumption averages 0.01 μmol/(gDW h) and depends on the NH4 concentration in the seawater and on the P content in the algal tissues ( r 2 = 0.40, p < 0.001).

Chemical composition and binary mixture of human urinary stones using FT-Raman spectroscopy method.

Science.gov (United States)

Selvaraju, R; Raja, A; Thiruppathi, G

2013-10-01

In the present study the human urinary stones were observed in their different chemical compositions of calcium oxalate monohydrate, calcium oxalate dihydrate, calcium phosphate, struvite (magnesium ammonium phosphate), uric acid, cystine, oxammite (ammonium oxalate monohydrate), natroxalate (sodium oxalate), glushinkite (magnesium oxalate dihydrate) and moolooite (copper oxalate) were analyzed using Fourier Transform-Raman (FT-Raman) spectroscopy. For the quantitative analysis, various human urinary stone samples are used for ratios calculation of binary mixtures compositions such as COM/COD, HAP/COD, HAP/COD, Uric acid/COM, uric acid/COD and uric acid/HAP. The calibration curve is used for further analysis of binary mixture of human urinary stones. For the binary mixture calculation the various intensities bands at 1462 cm(-1) (I(COM)), 1473 cm(-1) (I(COD)), 961 cm(-1) (I(HAP)) and 1282 cm(-1) (I(UA)) were used. Copyright © 2013 Elsevier B.V. All rights reserved.

Determination of phosphate phases in sewage sludge ash-based fertilizers by Raman microspectroscopy.

Science.gov (United States)

Vogel, Christian; Adam, Christian; McNaughton, Don

2013-09-01

The chemical form of phosphate phases in sewage sludge ash (SSA)-based fertilizers was determined by Raman microspectroscopy. Raman mapping with a lateral resolution of 5 × 5 μm(2) easily detected different compounds present in the fertilizers with the help of recorded reference spectra of pure substances. Quartz and aluminosilicates showed Raman bands in the range of 450-520 cm(-1). Phosphates with apatite structure and magnesium triphosphate were determined at around 960 and 980 cm(-1), respectively. Furthermore, calcium/magnesium pyrophosphates were detected in some samples.

Serum magnesium, phosphate and calcium in Nigerian children with ...

African Journals Online (AJOL)

Background: Biochemical abnormalities have been associated with sickle cell disease. Studies on phosphorus and magnesium in sickle cell disease have been conflicting. There is paucity of information on the role of these ions in the pathogenesis and management of sickle cell disease. This study was set out to determine ...

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

International Nuclear Information System (INIS)

Teutli S, E.A.

2007-01-01

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

Recovery of nitrogen from saponification wastewater by struvite precipitation.

Science.gov (United States)

Huang, Haiming; Xiao, Xianming; Yang, Liping; Yan, Bo

2010-01-01

In general, saponification wastewater produced from the separation process of rare-earth elements contains high ammonium concentration. In this study, a series of experiments were conducted to investigate the parameters to enhance the struvite precipitation potential for ammonium removal from the wastewater having an ammonium concentration of 4,100 mg/L. Experimental results showed that increasing the dose and grain size of pre-formed struvite, which was added as the seeding material in struvite reaction, could increase ammonium removal. The removal efficiency increased 7.6% when the dose of pre-formed struvite with crystal grain size range of 0.098-0.150 mm increased from 0 g/L to 60 g/L. Additionally, struvite precipitation was tested with the intermittent addition of magnesium and phosphate to utilize the struvite crystals formed during the reaction process as the seeding material for the subsequent reaction. The results revealed that intermittently adding magnesium 7 times effectively enhanced ammonium removal by around 8%, which was equivalent to that of using pre-formed struvite as the seeding material. Furthermore, the chemical composition of the struvite recovered with intermittent addition of magnesium was characterized, showing the struvite could be used as fertilizer. An economic evaluation indicated that intermittent addition of magnesium 7 times can save 13.4% cost for recovering per kg NH(4)(+) compared to that of bulk addition.

Influence of nutrition on feline calcium oxalate urolithiasis with emphasis on endogenous oxalate synthesis

NARCIS (Netherlands)

Dijcker, J.C.; Plantinga, E.A.; Baal, van J.; Hendriks, W.H.

2011-01-01

The prevalence of calcium oxalate (CaOx) uroliths detected in cats with lower urinary tract disease has shown a sharp increase over the last decades with a concomitant reciprocal decrease in the occurrence of struvite (magnesium ammonium phosphate) uroliths. CaOx stone-preventative diets are

Prevention of radioactive contamination in the manufacture of phosphate fertilizers

International Nuclear Information System (INIS)

Romero G, E.T.

1995-01-01

In this work was studied the separation of uranium from the phosphate rock to decrease the level of radioactivity in the phosphate fertilizers, this prevents the redistribution of uranium in the environment. The uranium leaching conditions from phosphate rock were estimated using alkaline solutions. The changes in the natural phosphate rock after leaching were studied. The amenability to separate the uranium from phosphate rock with ammonium carbonate / bicarbonate solution was determined. The uranium extraction was approximately 40%. The leaching conditions showed high selectivity for uranium without changes in the ore structure. The bulk ore was not dissolved. (Author)

Preparation and bioactivity of micro-arc oxidized calcium phosphate coatings

International Nuclear Information System (INIS)

Pan, Y.K.; Chen, C.Z.; Wang, D.G.; Lin, Z.Q.

2013-01-01

Calcium phosphate (CaP) coatings were prepared on ZK60 magnesium alloy by micro-arc oxidation (MAO) in electrolyte containing calcium acetate monohydrate (CH 3 COO) 2 Ca·H 2 O) and disodium hydrogen phosphate dodecahydrate (Na 2 HPO 4 ·12H 2 O). Scanning electron microscope (SEM), energy-dispersive X-ray spectrometry (EDX) and X-ray diffractometer (XRD) were employed to characterize the microstructure, elemental distribution and phase composition of the CaP coatings respectively. Simulated body fluid (SBF) immersion test was used to evaluate the coating degradability and bioactivity. After 30 days of SBF immersion, the CaP coatings effectively reduce the degradation rate. The surfaces of CaP coatings are covered by a new layer formed of numerous needle-like, spherical and columned calcium phosphates. SEM, EDX and XRD results suggest that these calcium phosphates are bioactive calcium phosphate phases such as hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 , HA) and calcium pyrophosphates (Ca 2 P 2 O 7 , CPP). The formation of these calcium phosphates indicates that the CaP coatings have bioactivity. - Highlights: • Bioactive CaP coatings are successfully formed on ZK60 magnesium alloy. • CaP coatings consist of MgO, MgF 2 , CaO, CaF 2 and Ca 3 (PO 4 ) 2 . • Needle-like, spherical and columned calcium phosphates formed in SBF. • CaP coatings exhibit bioactivity and low corrosion rate

Waffle production: influence of batter ingredients on sticking of waffles at baking plates-Part II: effect of fat, leavening agent, and water.

Science.gov (United States)

Huber, Regina; Schoenlechner, Regine

2017-05-01

Fresh egg waffles are continuously baked in tunnel baking ovens in industrial scale. Waffles that partly or fully stick to the baking plates cause significant product loss and increased costs. The aim of this study was, therefore, to investigate the effect of different recipe ingredients on the sticking behavior of waffles. In this second part, ingredients investigated were different leavening agents (sodium acid pyrophosphate, ammonium bicarbonate, magnesium hydroxide carbonate, or monocalcium phosphate), different fat sources (rapeseed oil, cocos fat, butter, or margarine), and different water sources (tap water 12°dH and distilled water). Within the different types of fats, solid fats with high amount of short-chain fatty acids (cocos fat or butter) decreased the number of sticking waffles compared to liquid oils (rapeseed oil). Regarding leavening agents, magnesium hydroxide carbonate and ammonium bicarbonate were superior to sodium acid pyrophosphate or monocalcium phosphate. Between the two water sources, effects were small.

Statistical media design for efficient polyhydroxyalkanoate production in Pseudomonas sp. MNNG-S.

Science.gov (United States)

Saranya, V; Rajeswari, V; Abirami, P; Poornimakkani, K; Suguna, P; Shenbagarathai, R

2016-07-03

Polyhydroxyalkanoate (PHA) is a promising polymer for various biomedical applications. There is a high need to improve the production rate to achieve end use. When a cost-effective production was carried out with cheaper agricultural residues like molasses, traces of toxins were incorporated into the polymer, which makes it unfit for biomedical applications. On the other hand, there is an increase in the popularity of using chemically defined media for the production of compounds with biomedical applications. However, these media do not exhibit favorable characteristics such as efficient utilization at large scale compared to complex media. This article aims to determine the specific nutritional requirement of Pseudomonas sp. MNNG-S for efficient production of polyhydroxyalkanoate. Response surface methodology (RSM) was used in this study to statistically design for PHA production based on the interactive effect of five significant variables (sucrose; potassium dihydrogen phosphate; ammonium sulfate; magnesium sulfate; trace elements). The interactive effects of sucrose with ammonium sulfate, ammonium sulfate with combined potassium phosphate, and trace element with magnesium sulfate were found to be significant (p production more than fourfold (from 0.85 g L(-1) to 4.56 g L(-1)).

Ammonia recovery from urine in a scaled-up Microbial Electrolysis Cell

NARCIS (Netherlands)

Zamora, Patricia; Georgieva, Tanya; Heijne, ter Annemiek; Sleutels, Tom H.J.A.; Jeremiasse, Adriaan W.; Saakes, Michel; Buisman, Cees J.N.; Kuntke, Philipp

2017-01-01

A two-step treatment system for nutrient and energy recovery from urine was successfully operated for six months. In the first step, phosphorus (P) was recovered as struvite (magnesium ammonium phosphate or MAP) in a MAP reactor. The effluent of this MAP reactor was used for total ammonia-nitrogen

Parallel nano-assembling of a multifunctional GO/HapNP coating on ultrahigh-purity magnesium for biodegradable implants

International Nuclear Information System (INIS)

Santos, C.; Piedade, C.; Uggowitzer, P.J.; Montemor, M.F.; Carmezim, M.J.

2015-01-01

Graphical abstract: - Highlights: • A GO/HapNP thin coating was applied on XHP-Mg using a parallel nano-assembling route. • The coating surface wettability can be controlled by adding HapNP and/or GO. • Nanostructured GO/HapNP/phosphate coating promotes the apatite mineralization. • Critical properties, including degradation on SBF, of the coating were studied. - Abstract: This work reports the one-step fabrication of a novel coating on ultra high purity magnesium using a parallel nano assembling process. The multifunctional biodegradable surface was obtained by adding hydroxyapatite nanoparticles (HapNP) plus graphene oxide (GO). The coating was characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffractometer (XRD), micro-Raman spectroscopy. The thin phosphate coating (thickness of 1 μm) reveals a uniform coverage with cypress like structures. The incorporation of HapNP and GO promotes the hydrophilic behavior of the coating surface. The results revealed that the proposed coating can be used to tailor the surface properties such as wettability by adjusting the contents of HapNP and GO. The in vitro degradation rate of the coated magnesium suggests that the presence of HapNP and GO/HapNP in the phosphate coating decreased the current density compared to the single phosphate coating and uncoated magnesium. This study also reveals the HapNP/GO/phosphate coating induces apatite formation, showing suitable degradability that makes it a promising coating candidate for enhanced bone regeneration

Parallel nano-assembling of a multifunctional GO/HapNP coating on ultrahigh-purity magnesium for biodegradable implants

Energy Technology Data Exchange (ETDEWEB)

Santos, C., E-mail: catarina.santos@estsetubal.ips.pt [EST Setúbal, DEM, Instituto Politécnico de Setúbal, Campus IPS, 2914-508 Setúbal (Portugal); CQE, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Piedade, C. [EST Setúbal, DEM, Instituto Politécnico de Setúbal, Campus IPS, 2914-508 Setúbal (Portugal); Uggowitzer, P.J. [Laboratory of Metal Physics and Technology, ETH Zurich, 8093 Zurich (Switzerland); Montemor, M.F. [CQE, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Carmezim, M.J. [EST Setúbal, DEM, Instituto Politécnico de Setúbal, Campus IPS, 2914-508 Setúbal (Portugal); CQE, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)

2015-08-01

Graphical abstract: - Highlights: • A GO/HapNP thin coating was applied on XHP-Mg using a parallel nano-assembling route. • The coating surface wettability can be controlled by adding HapNP and/or GO. • Nanostructured GO/HapNP/phosphate coating promotes the apatite mineralization. • Critical properties, including degradation on SBF, of the coating were studied. - Abstract: This work reports the one-step fabrication of a novel coating on ultra high purity magnesium using a parallel nano assembling process. The multifunctional biodegradable surface was obtained by adding hydroxyapatite nanoparticles (HapNP) plus graphene oxide (GO). The coating was characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffractometer (XRD), micro-Raman spectroscopy. The thin phosphate coating (thickness of 1 μm) reveals a uniform coverage with cypress like structures. The incorporation of HapNP and GO promotes the hydrophilic behavior of the coating surface. The results revealed that the proposed coating can be used to tailor the surface properties such as wettability by adjusting the contents of HapNP and GO. The in vitro degradation rate of the coated magnesium suggests that the presence of HapNP and GO/HapNP in the phosphate coating decreased the current density compared to the single phosphate coating and uncoated magnesium. This study also reveals the HapNP/GO/phosphate coating induces apatite formation, showing suitable degradability that makes it a promising coating candidate for enhanced bone regeneration.

Preparation and bioactivity of micro-arc oxidized calcium phosphate coatings

Energy Technology Data Exchange (ETDEWEB)

Pan, Y.K. [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Ji' nan, Shandong 250061 (China); School of Materials Science and Engineering, Shandong University, Ji' nan, Shandong 250061 (China); Chen, C.Z., E-mail: czchen@sdu.edu.cn [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Ji' nan, Shandong 250061 (China); School of Materials Science and Engineering, Shandong University, Ji' nan, Shandong 250061 (China); Wang, D.G.; Lin, Z.Q. [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Ji' nan, Shandong 250061 (China); School of Materials Science and Engineering, Shandong University, Ji' nan, Shandong 250061 (China)

2013-09-16

Calcium phosphate (CaP) coatings were prepared on ZK60 magnesium alloy by micro-arc oxidation (MAO) in electrolyte containing calcium acetate monohydrate (CH{sub 3}COO){sub 2}Ca·H{sub 2}O) and disodium hydrogen phosphate dodecahydrate (Na{sub 2}HPO{sub 4}·12H{sub 2}O). Scanning electron microscope (SEM), energy-dispersive X-ray spectrometry (EDX) and X-ray diffractometer (XRD) were employed to characterize the microstructure, elemental distribution and phase composition of the CaP coatings respectively. Simulated body fluid (SBF) immersion test was used to evaluate the coating degradability and bioactivity. After 30 days of SBF immersion, the CaP coatings effectively reduce the degradation rate. The surfaces of CaP coatings are covered by a new layer formed of numerous needle-like, spherical and columned calcium phosphates. SEM, EDX and XRD results suggest that these calcium phosphates are bioactive calcium phosphate phases such as hydroxyapatite (Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}, HA) and calcium pyrophosphates (Ca{sub 2}P{sub 2}O{sub 7}, CPP). The formation of these calcium phosphates indicates that the CaP coatings have bioactivity. - Highlights: • Bioactive CaP coatings are successfully formed on ZK60 magnesium alloy. • CaP coatings consist of MgO, MgF{sub 2}, CaO, CaF{sub 2} and Ca{sub 3}(PO{sub 4}){sub 2}. • Needle-like, spherical and columned calcium phosphates formed in SBF. • CaP coatings exhibit bioactivity and low corrosion rate.

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

Directory of Open Access Journals (Sweden)

Verónica Fernández

2017-10-01

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

Effect of the biodegradation rate controlled by pore structures in magnesium phosphate ceramic scaffolds on bone tissue regeneration in vivo.

Science.gov (United States)

Kim, Ju-Ang; Lim, Jiwon; Naren, Raja; Yun, Hui-Suk; Park, Eui Kyun

2016-10-15

Similar to calcium phosphates, magnesium phosphate (MgP) ceramics have been shown to be biocompatible and support favorable conditions for bone cells. Micropores below 25μm (MgP25), between 25 and 53μm (MgP53), or no micropores (MgP0) were introduced into MgP scaffolds using different sizes of an NaCl template. The porosities of MgP25 and MgP53 were found to be higher than that of MgP0 because of their micro-sized pores. Both in vitro and in vivo analysis showed that MgP scaffolds with high porosity promoted rapid biodegradation. Implantation of the MgP0, MgP25, and MgP53 scaffolds into rabbit calvarial defects (with 4- and 6-mm diameters) was assessed at two times points (4 and 8weeks), followed by analysis of bone regeneration. The micro-CT and histologic analyses of the 4-mm defect showed that the MgP25 and MgP53 scaffolds were degraded completely at 4weeks with simultaneous bone and marrow-like structure regeneration. For the 6-mm defect, a similar pattern of regeneration was observed. These results indicate that the rate of degradation is associated with bone regeneration. The MgP25 and MgP53 scaffold-implanted bone showed a better lamellar structure and enhanced calcification compared to the MgP0 scaffold because of their porosity and degradation rate. Tartrate-resistant acid phosphatase (TRAP) staining indicated that the newly formed bone was undergoing maturation and remodeling. Overall, these data suggest that the pore architecture of MgP ceramic scaffolds greatly influence bone formation and remodeling activities and thus should be considered in the design of new scaffolds for long-term bone tissue regeneration. The pore structural conditions of scaffold, including porosity, pore size, pore morphology, and pore interconnectivity affect cell ingrowth, mechanical properties and biodegradabilities, which are key components of scaffold in bone tissue regeneration. In this study, we designed hierarchical pore structure of the magnesium phosphate (Mg

A Review on the Chemically Bonded Phosphate Ceramics as a Binder of Next Generation

International Nuclear Information System (INIS)

Yang, Jae Hwan; Kang, K. H.; Na, S. H.; Lee, J. W.

2010-12-01

Phosphate ceramics which is fabricated by means of acid-base reaction is a new material that may be used in many fields. This report introduces the technology of phosphate ceramics, especially the process of magnesium phosphate ceramics fabrication and properties in detail. We expect that researchers and engineers who are seeking to develop the technology of wasteform containing spent fuel waste are referred to this document

Therapeutic Interference With Vascular Calcification—Lessons From Klotho-Hypomorphic Mice and Beyond

Directory of Open Access Journals (Sweden)

Florian Lang

2018-05-01

Full Text Available Medial vascular calcification, a major pathophysiological process associated with cardiovascular disease and mortality, involves osteo-/chondrogenic transdifferentiation of vascular smooth muscle cells (VSMCs. In chronic kidney disease (CKD, osteo-/chondrogenic transdifferentiation of VSMCs and, thus, vascular calcification is mainly driven by hyperphosphatemia, resulting from impaired elimination of phosphate by the diseased kidneys. Hyperphosphatemia with subsequent vascular calcification is a hallmark of klotho-hypomorphic mice, which are characterized by rapid development of multiple age-related disorders and early death. In those animals, hyperphosphatemia results from unrestrained formation of 1,25(OH2D3 with subsequent retention of calcium and phosphate. Analysis of klotho-hypomorphic mice and mice with vitamin D3 overload uncovered several pathophysiological mechanisms participating in the orchestration of vascular calcification and several therapeutic opportunities to delay or even halt vascular calcification. The present brief review addresses the beneficial effects of bicarbonate, carbonic anhydrase inhibition, magnesium supplementation, mineralocorticoid receptor (MR blockage, and ammonium salts. The case is made that bicarbonate is mainly effective by decreasing intestinal phosphate absorption, and that carbonic anhydrase inhibition leads to metabolic acidosis, which counteracts calcium-phosphate precipitation and VSMC transdifferentiation. Magnesium supplementation, MR blockage and ammonium salts are mainly effective by interference with osteo-/chondrogenic signaling in VSMCs. It should be pointed out that the, by far, most efficient substances are ammonium salts, which may virtually prevent vascular calcification. Future research will probably uncover further therapeutic options and, most importantly, reveal whether these observations in mice can be translated into treatment of patients suffering from vascular calcification, such

Phase assemblage study and cytocompatibility property of heat treated potassium magnesium phosphate-silicate ceramics.

Science.gov (United States)

Kumar, Ravi; Kalmodia, Sushma; Nath, Shekhar; Singh, Dileep; Basu, Bikramjit

2009-08-01

This article reports the study on a new generation bioactive ceramic, based on MgKPO(4) (Magnesium Potassium Phosphate, abbreviated as MKP) for biomedical applications. A series of heat treatment experiments on the slip cast silica (SiO(2)) containing MKP ceramics were carried out at 900, 1,000 and 1,100 degrees C for 4 h in air. The density of the slip cast ceramic increases to 2.5 gm/cm(3) upon heat treatment at 900 degrees C. However, no significant change in density is measured upon heat treatment to higher temperature of 1,000 and 1,100 degrees C. On the basis of XRD results, the presence of K(2)MgSi(5)O(12) and dehydrated MgKPO(4) were confirmed and complementary information has also been obtained using FT-IR and Raman spectroscopy. In order to confirm the in vitro cytocompatibility property, the cell culture tests were carried out on selected samples and the results reveal good cell adhesion and spreading of L929 mouse fibroblast cells. MTT assay analysis with L929 cells confirmed non-cytotoxic behavior of MKP containing ceramics and the results are comparable with sintered HAp ceramics. It is expected that the newly developed MKP based materials could be a good substitute for hydroxyapatite (HAp or HA) based bioceramics.

Effect of electrolyte additives on performance of plasma electrolytic oxidation films formed on magnesium alloy AZ91D

International Nuclear Information System (INIS)

Duan, Hongping; Yan, Chuanwei; Wang, Fuhui

2007-01-01

Various plasma electrolytic oxidation (PEO) films were prepared on magnesium alloy AZ91D in a silicate bath with different additives such as phosphate, fluoride and borate. Effects of the additives on chemical composition and corrosion resistance of the PEO films were examined by means of scanning electron microscopy (SEM), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in 3.5% NaCl solution. The results showed that the PEO films obtained in solutions with both borate and fluoride had better corrosion resistance. In order to understand the corrosion mechanism of PEO films on magnesium alloy AZ91D, electronic property of the magnesium electrode with PEO films was studied by Mott-Schottky approach in a solution containing borate and chloride. The results indicated that magnesium electrodes with and without PEO films all exhibited n-type semiconducting property. However, in comparison with the magnesium electrode treated in solutions containing phosphate or borate, the electrode treated in solutions containing both borate and fluoride (M-film) had lower donor concentration and much negative flat band potential; therefore, the M-film had lower reactivity and higher corrosion resistance

Structural Analysis of DNA Interactions with Magnesium Ion Studied by Raman Spectroscopy

OpenAIRE

S. Ponkumar; P. Duraisamy; N. Iyandurai

2011-01-01

Problem statement: In the present study, FT Raman spectroscopy had been used to extend our knowledge about Magnesium ion - DNA interactions at various volume ratios (1:50, 1:20, 1:10 and 1:5). Approach: The analysis of FT Raman data supported the existence of structural specificities in the interaction and also the stability of DNA secondary structure. Results: Results from the Raman spectra clearly indicate that the interaction of Magnesium ion with DNA is mainly through the phosphate groups...

Flame retardancy of polyamide 6 hybrid fibers: Combined effects of α-zirconium phosphate and ammonium sulfamate

Directory of Open Access Journals (Sweden)

Hengxue Xiang

2017-06-01

Full Text Available Synergistic effect between α-zirconium phosphate (α-ZrP and ammonium sulfamate (AS for enhanced flame retardant properties of Polyamide 6 (PA6 was investigated by using oxygen index instrument, cone calorimeter, thermogravimetric analyzer (TGA, Instron universal test machine and scanning electron microscopy (SEM. PA6/AS/α-ZrP ternary hybrid materials with various contents of α-ZrP and AS were fabricated by melt-mixing method. The result from flammability indicated that the Limiting oxygen index (LOI and Underwriters Laboratories-94 (UL-94 rating of PA6/AS/α-ZrP were significantly accelerated under the coordinating function of α-ZrP and AS. Moreover, the thermal stability for PA6/AS/α-ZrP studied by TGA also demonstrated this synergistic effect between α-ZrP and AS on the heat resistance. The effects of the usage amount of α-ZrP and AS on mechanical properties were analyzed by using uniaxial tensile test. It was found that the addition of AS provided negative effects on the tensile strength of PA6/AS/α-ZrP, however, the adverse trends that mentioned above could be overcome by using the well dispersed α-ZrP.

Effectivity of fluoride treatment on hydrogen and corrosion product generation in temporal implants for different magnesium alloys.

Science.gov (United States)

Trinidad, Javier; Arruebarrena, Gurutze; Marco, Iñigo; Hurtado, Iñaki; Sáenz de Argandoña, Eneko

2013-12-01

The increasing interest on magnesium alloys relies on their biocompatibility, bioabsorbility and especially on their mechanical properties. Due to these characteristics, magnesium alloys are becoming a promising solution to be used, as temporary implants. However, magnesium alloys must overcome their poor corrosion resistance. This article analyses the corrosion behaviour in phosphate-buffered saline solution of three commercial magnesium alloys (AZ31B, WE43 and ZM21) as well as the influence of fluoride treatment on their corrosion behaviour. It is shown that the corrosion rate of all the alloys is decreased by fluoride treatment. However, fluoride treatment affects each alloy differently.

Magnesium-molybdenum compounds as matrixes of 99m Tc generators

International Nuclear Information System (INIS)

Jimenez M, T.S.

2005-01-01

In order to finding new production alternatives of 99 Mo/ 99m Tc generators, easy to produce and with high elutriation efficiencies, it is proposed in this work to develop a generator with basis of magnesium and molybdenum that could be irradiated after their synthesis, given the short half life of the only radioisotope produced by the magnesium: 27 Mg (t 1/2 = 9.46 m). It is necessary to mention that have not been reported works in relation to this type of compound, being then important to carry out basic studies on the formation and behavior of these in relation to their matrix functions of those generated of 99 Mo/ 99m Tc. In this work it was determined the effect that has, the magnesium salt used in the synthesis of those molybdenum-magnesium compounds, the molar ratio Mo: Mg, the concentration of the magnesium salt, the pH of the used ammonium molybdates in the synthesis of the final compounds and the washing of the molybdates of synthesized magnesium, in the performance of the 99 Mo/ 99m Tc generators. Parameters like the elutriation efficiency, the radionuclide purity, radiochemical and chemical of the eluates and their pH, were determined in each case, also its were characterized the synthesized compounds using: neutron activation analysis (NAA), X-ray diffraction (XRD) and scanning electron microscopy of high vacuum (SEM), besides of complementary techniques: infrared spectroscopy (IR), and thermal gravimetric analysis (TGA). (Author)

Magnesium–Gold Alloy Formation by Underpotential Deposition of Magnesium onto Gold from Nitrate Melts

Directory of Open Access Journals (Sweden)

Vesna S. Cvetković

2017-03-01

Full Text Available Magnesium underpotential deposition on gold electrodes from magnesium nitrate –ammonium nitrate melts has been investigated. Linear sweep voltammetry and potential step were used as electrochemical techniques. Scanning electron microscopy (SEM, energy dispersive spectrometry (EDS and X-ray diffraction (XRD were used for characterization of obtained electrode surfaces. It was observed that reduction processes of nitrate, nitrite and traces of water (when present, in the Mg underpotential range studied, proceeded simultaneously with magnesium underpotential deposition. There was no clear evidence of Mg/Au alloy formation induced by Mg UPD from the melt made from eutectic mixture [Mg(NO32·6H2O + NH4NO3·XH2O]. However, EDS and XRD analysis showed magnesium present in the gold substrate and four different Mg/Au alloys being formed as a result of magnesium underpotential deposition and interdiffusion between Mg deposit and Au substrate from the melt made of a nonaqueous [Mg(NO32 + NH4NO3] eutectic mixture at 460 K.

Bulletin of Materials Science | News

Indian Academy of Sciences (India)

Struvite or magnesium ammonium phosphate hexahydrate (MAP) is one of the components of urinary stone. Struvite stones are commonly found in women. It forms in human beings as a result of urinary tract infection with urea splitting organisms. These stones can grow rapidly forming “staghorn-calculi”, which is a painful ...

Evidence for two compartments of exchangeable calcium in isolated rat liver mitochondria obtained using a 45Ca exchange technique in the presence of magnesium, phosphate, and ATPase at 370C

International Nuclear Information System (INIS)

Barritt, G.J.

1981-01-01

The distribution of calcium between isolated rat liver mitochondria and the extramitochondrial medium at 37 degrees C and in the presence of 2 mM inorganic phosphate, 3 mM ATP, 0.05 or 1.1 mM free magnesium and a calcium buffer, nitrilotriacetic acid, was investigated using a 45 Ca exchange technique. The amounts of 40 Ca in the mitochondria and medium were allowed to reach equilibrium before initiation of the measurement of 45 Ca exchange. At 0.05 mM free magnesium and initial extramitochondrial free calcium concentrations of between 0.15 and 0.5 microM, the mitochondria accumulated calcium until the extramitochondrial free calcium concentration was reduced to 0.15 microM. Control experiments showed that the mitochondria were stable under the incubation conditions employed. The 45 Ca exchange data were found to be consistent with a system in which two compartments of exchangeable calcium are associated with the mitochondria. Changes in the concentration of inorganic phosphate did not significantly affect the 45 Ca exchange curves, whereas an increase in the concentration of free magnesium inhibited exchange. The maximum rate of calcium outflow from the mitochondria was estimated to be 1.7 nmol/min per mg of protein, and the value of K0.5 for intramitochondrial exchangeable calcium to be about 1.6 nmol per mg of protein. Ruthenium Red decreased the fractional transfer rate for calcium inflow to the mitochondria while nupercaine affected principally the fractional transfer rates for the transfer of calcium between the two mitochondrial compartments. The use of the incubation conditions and 45 Ca exchange technique described in this report for studies of the effects of agents which may alter mitochondrial calcium uptake or release (e.g., the pre-treatment of cells with hormones) is briefly discussed

Leaching behavior of phosphate-bonded ceramic waste forms

International Nuclear Information System (INIS)

Singh, D.; Wagh, A.S.; Jeong, S.Y.; Dorf, M.

1996-04-01

Over the last few years, Argonne National Laboratory has been developing room-temperature-setting chemically bonded phosphate ceramics for solidifying and stabilizing low-level mixed wastes. This technology is crucial for stabilizing waste streams that contain volatile species and off-gas secondary waste streams generated by high-temperature treatment of such wastes. We have developed a magnesium phosphate ceramic to treat mixed wastes such as ash, salts, and cement sludges. Waste forms of surrogate waste streams were fabricated by acid-base reactions between the mixtures of magnesium oxide powders and the wastes, and phosphoric acid or acid phosphate solutions. Dense and hard ceramic waste forms are produced in this process. The principal advantage of this technology is that the contaminants are immobilized by both chemical stabilization and subsequent microencapsulation of the reaction products. This paper reports the results of durability studies conducted on waste forms made with ash waste streams spiked with hazardous and radioactive surrogates. Standard leaching tests such as ANS 16.1 and TCLP were conducted on the final waste forms. Fates of the contaminants in the final waste forms were established by electron microscopy. In addition, stability of the waste forms in aqueous environments was evaluated with long-term water-immersion tests

Use of combined ion exchangers on the basis of KU-23 and KM-2p cation exchangers for purification of ammonium molybdate and tungstate solutions from phosphate, arsenate, and silicate impurities

International Nuclear Information System (INIS)

Blokhin, A.A.; Majorov, D.Yu.; Kopyrin, A.A.; Taushkanov, V.P.

2002-01-01

Using the Tracer technique ( 32 P) and elementary analysis, potentiality of using combined ionites on the basis of macroporous cation-exchange resins KU-23 or KM-2p and hydrated zirconium oxide for purification of concentrated solutions of ammonium molybdate and tungstate from phosphate-, arsenate-, and silicate-ions impurities was studied. High selectivity of the combined ionites towards impurity ions was ascertained, which permits reducing the content of impurities by a factor of 50-100 compared with the initial one [ru

Enzymatic, urease-mediated mineralization of gellan gum hydrogel with calcium carbonate, magnesium-enriched calcium carbonate and magnesium carbonate for bone regeneration applications.

Science.gov (United States)

Douglas, Timothy E L; Łapa, Agata; Samal, Sangram Keshari; Declercq, Heidi A; Schaubroeck, David; Mendes, Ana C; der Voort, Pascal Van; Dokupil, Agnieszka; Plis, Agnieszka; De Schamphelaere, Karel; Chronakis, Ioannis S; Pamuła, Elżbieta; Skirtach, Andre G

2017-12-01

Mineralization of hydrogel biomaterials is considered desirable to improve their suitability as materials for bone regeneration. Calcium carbonate (CaCO 3 ) has been successfully applied as a bone regeneration material, but hydrogel-CaCO 3 composites have received less attention. Magnesium (Mg) has been used as a component of calcium phosphate biomaterials to stimulate bone-forming cell adhesion and proliferation and bone regeneration in vivo, but its effect as a component of carbonate-based biomaterials remains uninvestigated. In the present study, gellan gum (GG) hydrogels were mineralized enzymatically with CaCO 3 , Mg-enriched CaCO 3 and magnesium carbonate to generate composite biomaterials for bone regeneration. Hydrogels loaded with the enzyme urease were mineralized by incubation in mineralization media containing urea and different ratios of calcium and magnesium ions. Increasing the magnesium concentration decreased mineral crystallinity. At low magnesium concentrations calcite was formed, while at higher concentrations magnesian calcite was formed. Hydromagnesite (Mg 5 (CO 3 ) 4 (OH) 2 .4H 2 O) formed at high magnesium concentration in the absence of calcium. The amount of mineral formed and compressive strength decreased with increasing magnesium concentration in the mineralization medium. The calcium:magnesium elemental ratio in the mineral formed was higher than in the respective mineralization media. Mineralization of hydrogels with calcite or magnesian calcite promoted adhesion and growth of osteoblast-like cells. Hydrogels mineralized with hydromagnesite displayed higher cytotoxicity. In conclusion, enzymatic mineralization of GG hydrogels with CaCO 3 in the form of calcite successfully reinforced hydrogels and promoted osteoblast-like cell adhesion and growth, but magnesium enrichment had no definitive positive effect. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Study on Release Characteristics and Recovery of Nitrogen and Phosphorus during the Anaerobic Fermentation of Excess Sludge

Science.gov (United States)

Qin, Yuqian; Hu, Shulong

2018-01-01

Ammonia nitrogen and phosphate are produced from activated excess sludge under anaerobic conditions,and will cause eutrophication upon release to the environment. A study of sludge from a eutrophication was carried out, to obtain knowledge of the nitrogen and phosphorus release patterns of the excess sludge during anaerobic fermentation and the recycling efficiency of both nitrogen and phosphorus, by adding magnesium salt and alkali solution to the supernatant liquors. The results showed that the concentration of ammonia nitrogen and phosphate of the supernatant liquors continued to increase during the process of anaerobic digestion, and both reached a maximum in 12 days, at 41.56mg / L and 47.02 mg / L respectively. By adding magnesium salt to the supernatant with c(Mg): c(P) = 1.1:1, adjusting pH value to 9.0 ∼ 9.5, phosphorus recovery rate reached up to 95.0%, while the recovery rate of ammonia was 47.4%, resulting in the formation of a sediment of magnesium ammonium phosphate, or MAP, which may he used as a high-quality fertilizer.

Electrophoretic deposition of magnesium silicates on titanium implants: Ion migration and silicide interfaces

Energy Technology Data Exchange (ETDEWEB)

Afshar-Mohajer, M. [Center for Advanced Manufacturing and Material Processing, Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Yaghoubi, A., E-mail: yaghoubi@siswa.um.edu.my [Center for High Impact Research, University of Malaya, Kuala Lumpur 50603 (Malaysia); Ramesh, S., E-mail: ramesh79@um.edu.my [Center for Advanced Manufacturing and Material Processing, Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Bushroa, A.R.; Chin, K.M.C.; Tin, C.C. [Center for Advanced Manufacturing and Material Processing, Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Chiu, W.S. [Low Dimensional Materials Research Center, Department of Physics, University of Malaya, Kuala Lumpur 50603 (Malaysia)

2014-07-01

Magnesium silicates (Mg{sub x}SiO{sub y}) and in particular forsterite (Mg{sub 2}SiO{sub 4}) owing to their low thermal expansion mismatch with metals are promising materials for bioactive coating of implants. Here, we report the electrophoretic deposition (EPD) of forsterite onto titanium substrates using different precursors. Unlike bulk samples which achieve full stoichiometry only beyond 1400 °C, non-stoichiometric magnesium silicate rapidly decomposes into magnesium oxide nanowires during sintering. Elemental mapping and X-ray diffraction suggest that oxygen diffusion followed by ion exchange near the substrate leads to formation of an interfacial Ti{sub 5}Si{sub 3} layer. Pre-annealed forsterite powder on the other hand shows a comparatively lower diffusion rate. Overall, magnesium silicate coatings do not exhibit thermally induced microcracks upon sintering as opposed to calcium phosphate bioceramics which are currently in use.

Magnesium, magnesium alloys, and magnesium composites

National Research Council Canada - National Science Library

Gupta, M; Sharon, Nai Mui Ling

2011-01-01

"Properties of Magnesium Composites for Material Scientists, Engineers and Selectors is the first book-length reference to provide an insight into current and future magnesium-based materials in terms...

Evolution of the dicalcium phosphate-dihydrate (DCPD coating created by large amplitude sinusoidal voltammetry (LASV on corrosion resistance of the ZW3 magnesium alloy in chloride containing environment

Directory of Open Access Journals (Sweden)

Kajánek D.

2018-02-01

Full Text Available The contribution is focused on the preparation of coating based on the dicalcium phosphate-dihydrate (DCPD on the surface of ZW3 magnesium alloy. For the preparation of the coating a cathodic electrodeposition technique called Large Amplitude Sinusoidal Voltammetry (LASV was used. The DCPD layer was prepared at the temperature of 22 ± 2 °C in electrolyte composed of 0.1M Ca(NO3.4H2O, 0.06 M NH4H2PO4 and H2O2. Electrochemical characteristics were evaluated by electrochemical impedance spectroscopy (EIS in 0.1M NaCl solution. The obtained data in form of Nyquist plots were analysed by the equivalent circuit method. It is clear from the measured values of polarization resistance Rp that dicalcium phosphate-dihydrate (DCPD layer prepared by LASV electro-deposition technique improved corrosion resistance of ZW3 alloy in the chosen environment.

Biomineralization of carbonate and phosphate by moderately halophilic bacteria

NARCIS (Netherlands)

Sánchez-Román, Mónica; Rivadeneyra, Maria A.; Vasconcelos, Crisogono; McKenzie, Judith A.

We investigated the precipitation of carbonate and phosphate minerals by 19 species of moderately halophilic bacteria using media with variable Mg 2+/Ca2+ ratios. The precipitated minerals were calcite, magnesium (Mg) calcite, and struvite (MgNH4PO4· 6H2O) in variable proportions depending on the

Novel hybrid sol-gel coatings for corrosion protection of AZ31B magnesium alloy

International Nuclear Information System (INIS)

Lamaka, S.V.; Montemor, M.F.; Galio, A.F.; Zheludkevich, M.L.; Trindade, C.; Dick, L.F.; Ferreira, M.G.S.

2008-01-01

This work aims to develop and study new anticorrosion films for AZ31B magnesium alloy based on the sol-gel coating approach. Hybrid organic-inorganic sols were synthesized by copolymerization of epoxy-siloxane and titanium or zirconium alkoxides. Tris(trimethylsilyl) phosphate was also used as additive to confer additional corrosion protection to magnesium-based alloy. A sol-gel coating, about 5-μm thick, shows good adhesion to the metal substrate and prevents corrosion attack in 0.005 M NaCl solution for 2 weeks. The sol-gel coating system doped with tris(trimethylsilyl)-phosphate revealed improved corrosion protection of the magnesium alloy due to formation of hydrolytically stable Mg-O-P chemical bonds. The structure and the thickness of the sol-gel film were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The corrosion behaviour of AZ31B substrates pre-treated with the sol-gel derived hybrid coatings was tested by electrochemical impedance spectroscopy (EIS). The chemical composition of the silylphosphate-containing sol-gel film at different depths was investigated by X-ray photoelectron spectroscopy (XPS) with depth profiling

Early metabolic effects and mechanism of ammonium transport in yeast

International Nuclear Information System (INIS)

Pena, A.; Pardo, J.P.; Ramirez, J.

1987-01-01

Studies were performed to define the effects and mechanism of NH+4 transport in yeast. The following results were obtained. Glucose was a better facilitator than ethanol-H 2 O 2 for ammonium transport; low concentrations of uncouplers or respiratory inhibitors could inhibit the transport with ethanol as the substrate. With glucose, respiratory inhibitors showed only small inhibitory effects, and only high concentrations of azide or trifluoromethoxy carbonylcyanide phenylhydrazone could inhibit ammonium transport. Ammonium in the free state could be concentrated approximately 200-fold by the cells. Also, the addition of ammonium produced stimulation of both respiration and fermentation; an increased rate of H+ extrusion and an alkalinization of the interior of the cell; a decrease of the membrane potential, as monitored by fluorescent cyanine; an immediate decrease of the levels of ATP and an increase of ADP, which may account for the stimulation of both fermentation and respiration; and an increase of the levels of inorganic phosphate. Ammonium was found to inhibit 86Rb+ transport much less than K+. Also, while K+ produced a competitive type of inhibition, that produced by NH4+ was of the noncompetitive type. From the distribution ratio of ammonium and the pH gradient, an electrochemical potential gradient of around -180 mV was calculated. The results indicate that ammonium is transported in yeast by a mechanism similar to that of monovalent alkaline cations, driven by a membrane potential. The immediate metabolic effects of this cation seem to be due to an increased [H+]ATPase, to which its transport is coupled. However, the carriers seem to be different. The transport system studied in this work was that of low affinity

Bone mineral response to ammonium sulphate offered as a lick supplement in beef calves

Directory of Open Access Journals (Sweden)

L.E. Motsei

2006-06-01

Full Text Available Sixteen Bonsmara calves (4 males, 12 females between 10 and 18 months of age were blocked according to age and sex and randomly assigned to 2 groups. They were offered licks containing bone meal and salt (50:50 ratio (control and bone meal and ammonium sulphate (NH4SO4 at 1.25, 2.5, 5, 10, 15, and 18 % (treatment to evaluate the effects of dietary anions on bone phosphate (P concentration. Bone P concentration was significantly (P<0.05 higher in the NH4SO4 group compared with the control group, indicating that NH4SO4 was able to increase the P content of bone at each of the 6 concentrations used in the lick relative to the control animals, thereby improving the P status of the animals. Ammonium sulphate at 15% and 18% in the lick also significantly (P <0.05 increased bone P compared with the lower concentrations of NH4SO4. Bone calcium (Ca fluctuated as a result of the acidogenic lick. There was absorption of Ca when P was being resorbed and resorption of Ca when P was being absorbed into and out of bone. Bone Ca:P ratio ranged from 3.2 to 6.4 among the control group and 1.6 to 4.3 among the treatment group. Animals receiving the acidogenic lick had a higher percentage ash compared to the control group for most of the experimental period. Bone magnesium (Mg fluctuated in response to the acidogenic lick, and it was difficult to show a relationship between bone Mg and Ca or P. The overall mean cortical bone thickness was significantly (P < 0.05 greater in treatment (1.60 mm compared with control (1.43 mm calves and this was also true at sampling periods 2, 4, 5 and 6. Bone thickness followed bone P and not bone Ca. Results from this research indicate that the addition of ammonium sulphate to a lick had a beneficial effect in improving the P status by increasing bone P and improving the mineral status of bone by increasing the thickness of cortical bone and percentage ash.

Properties of concretes and wood composites using a phosphate-based binder

Science.gov (United States)

Hong, Luong Thanh

Magnesium potassium phosphate ceramics are from the family of phosphate-based cements which can be used as alternatives to Portland cements. In this study, concretes and wood composites were produced using magnesium potassium phosphate ceramic binders and supplementary materials including fly ash, sand, silica fume and sawdust. Bentonite, Delvo Stabilizer and baking soda were used as additives to increase the workability and the setting time of the fresh mixutres and decrease the density of the hardened products. The materials were then reinforced with chopped glass-fibers or textile glass-fabrics to increase their hardened properties. At 50% fly ash by total mass of the binder, the concretes had compressive strength and density of 33 MPa and 2170 kg/m3, respectively, after 90 days of simple curing. At 20% fly ash by total mass of the binder, the wood composites had compressive strength and density of 13 MPa and 1320 kg/m3, respectively, after 90 days. The flexural strengths were about 10% to 47% of the corresponding cylinder compressive strengths for these mixes. Increases in both compressive and flexural strengths for these mixes were observed with the addition of chopped glass-fibers or textile glass-fabrics.

Chemical synthesis of nanocrystalline magnesium aluminate spinel via nitrate-citrate combustion route

International Nuclear Information System (INIS)

Saberi, Ali; Golestani-Fard, Farhad; Sarpoolaky, Hosein; Willert-Porada, Monika; Gerdes, Thorsten; Simon, Reinhard

2008-01-01

Nanocrystalline magnesium aluminate spinel (MgAl 2 O 4 ) was synthesized using metal nitrates, citric acid and ammonium solutions. The precursor and the calcined powders at different temperatures were characterized by X-ray diffraction (XRD), simultaneous thermal analysis (STA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The combustion mechanism was also studied by a quadrupole mass spectrometer (QMS) which coupled to STA. The generated heat through the combustion of the mixture of ammonium nitrate and citrate based complexes decreased the synthesis temperature of MgAl 2 O 4 spinel. The synthesized MgAl 2 O 4 spinel at 900 deg. C has faced shape with crystallite size in the range of 18-24 nm

Availability of native and added phosphates for the soil

International Nuclear Information System (INIS)

Scivittaro, W.B.; Boaretto, A.E.; Muraoka, T.

1995-01-01

In superficial composite samples of two Red-Yellow Latosols with different physical and chemical properties, analyses were carried out on inorganic form of phosphorus as well as the availability of native and added phosphates. The method applied was soil phosphorus fractionation associated with isotopic dilution technique ( 32 P). The samples were taken from pots containing soils incubated for a month with fluid phosphatic fertilizers (phosphoric acid and 10-30-00 suspension) and solid phosphatic fertilizers (mono ammonium phosphate and triple superphosphate), at the rate of 210 mg P 2 O 5 /kg of soil. A control treatment was included. In both soils the availability of inorganic phosphorus fractions decreased at the following order: H 2 O-P > Al-P > Fe-P > CA-P > occluded-P. The water soluble and aluminium phosphates represented the main source of available P for the newly fertilizer, the iron phosphates were also an important source of available phosphorus. The soil phosphorus fixing capacity influenced the availability of native and added phosphates. (author). 17 refs, 3 tabs

A study on synthetic method and material characteristics of magnesium ammine chloride as ammonia transport materials for solid SCR

Energy Technology Data Exchange (ETDEWEB)

Shin, Jong Kook; Yoon, Cheon Seog [Dept. of Mechanical Engineering, Hannam University, Daejeon (Korea, Republic of); Kim, Hong Suk [Engine Research Center, Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

2015-11-15

Among various ammonium salts and metal ammine chlorides used as solid materials for the sources of ammonia with solid SCR for lean NOx reduction, magnesium ammine chloride was taken up for study in this paper because of its ease of handling and safety. Lab-scale synthetic method of magnesium ammine chloride were studied for different durations, temperatures, and pressures with proper ammonia gas charged, as a respect of ammonia gas adsorption rate(%). To understand material characteristics for lab-made magnesium ammine chloride, DA, IC, FT-IR, XRD and SDT analyses were performed using the published data available in literature. From the analytical results, the water content in the lab-made magnesium ammine chloride can be determined. A new test procedure for water removal was proposed, by which the adsorption rate of lab-made sample was found to be approximately 100%.

A study on synthetic method and material characteristics of magnesium ammine chloride as ammonia transport materials for solid SCR

International Nuclear Information System (INIS)

Shin, Jong Kook; Yoon, Cheon Seog; Kim, Hong Suk

2015-01-01

Among various ammonium salts and metal ammine chlorides used as solid materials for the sources of ammonia with solid SCR for lean NOx reduction, magnesium ammine chloride was taken up for study in this paper because of its ease of handling and safety. Lab-scale synthetic method of magnesium ammine chloride were studied for different durations, temperatures, and pressures with proper ammonia gas charged, as a respect of ammonia gas adsorption rate(%). To understand material characteristics for lab-made magnesium ammine chloride, DA, IC, FT-IR, XRD and SDT analyses were performed using the published data available in literature. From the analytical results, the water content in the lab-made magnesium ammine chloride can be determined. A new test procedure for water removal was proposed, by which the adsorption rate of lab-made sample was found to be approximately 100%

Spectrophotometric Determination of Nitrate and Phosphate Levels ...

African Journals Online (AJOL)

MBI

2013-04-09

Apr 9, 2013 ... may help in the growth of algae (Beavington,. 1977). Determination of phosphate ion in drinking water. 50cm3 of water sample was pipetted into a 500cm3 volumetric flask, 5cm3 of Ammonium molybdate solution and 3.0cm3 of ascorbic acid were added with swirling, the mixture was diluted to the mark with ...

Spectrographic determination of impurities in ammonium hydrogen fluoride samples

International Nuclear Information System (INIS)

Roca, M.; Capdevila, C.; Alduan, F.A.

1976-01-01

The quantitative spectrographic trace determination of Al, B, Cr, Cu, Fe, Mn, Mo, Ni, Pb and Si in ammonium hydrogen fluoride samples is considered. 10 A dc arc excitation and graphite electrodes with crate either 4.5 mm or 8 mm deep are employed. A comparison of various matrices such as graphite, gallium oxide, germanium oxide, magnesium oxide and zinc oxide, in the ratios 1:1 and 1:3, as well as a mixture 50% graphite - 50% zinc oxide in the ratio 1:1 is included. Zinc oxide in the ratio 1:1 and 4x8 mm craters show the best over-all results. (author)

Topography, wetting, and corrosion responses of electrodeposited hydroxyapatite and fluoridated hydroxyapatite on magnesium.

Science.gov (United States)

Assadian, Mahtab; Jafari, Hassan; Ghaffari Shahri, Seyed Morteza; Idris, Mohd Hasbullah; Almasi, Davood

2016-08-12

In this study, different types of calcium-phosphate phases were coated on NaOH pre-treated pure magnesium. The coating was applied by electrodeposition method in order to provide higher corrosion resistance and improve biocompatibility for magnesium. Thickness, surface morphology and topography of the coatings were analyzed using optical, scanning electron and atomic-force microscopies, respectively. Composition and chemical bonding, crystalline structures and wettability of the coatings were characterized using energy-dispersive and attenuated total reflectance-Fourier transform infrared spectroscopies, grazing incidence X-ray diffraction and contact angle measurement, respectively. Degradation behavior of the coated specimens was also investigated by potentiodynamic polarization and immersion tests. The experiments proved the presence of a porous coating dominated by dicalcium-phosphate dehydrate on the specimens. It was also verified that the developed hydroxyapatite was crystallized by alkali post-treatment. Addition of supplemental fluoride to the coating electrolyte resulted in stable and highly crystallized structures of fluoridated hydroxyapatite. The coatings were found effective to improve biocompatibility combined with corrosion resistance of the specimens. Noticeably, the fluoride supplemented layer was efficient in lowering corrosion rate and increasing surface roughness of the specimens compared to hydroxyapatite and dicalcium-phosphate dehydrates layers.

A new technique for the synthesis of ammonium phosphomolybdate: precipitation in resin support

International Nuclear Information System (INIS)

Matsuda, H.T.

1977-01-01

A technique for synthesizing ammonium molybdophosphate, an inorganic ion exchanger which retains selectively cesium-137 from a mixture of fission products, employing a strong anionic resin, saturated with molybdate anions, is presented. This method enables the precipitation of ammonium molybdophosphate directly into the resinous structure by adding dihydrogen ammonium phosphate in 7,5M HNO 3 . The reactants maintened at 60 0 C for a period of four hours has been found to be the optimum condition for a maximum yield of this compound (anionic resin-ammonium molybdophosphate = R-AMP). The tests performed for characterizing this compound are: molybdenum-phosphorus ratio determination, electronic absorption spectra, infra-red absorption spectra, reflection microscopy observations, electron probe micro-analysis and X-ray powder patterns. The analysis confirmed the presence of the ammonium molybdophosphate in the resinous structure, permitting, thereby, its use as a cation exchanger. R-AMP showed a capacity of 0,48mE/g of dry material. The cesium retention studies were made using columns charged with R-AMP compound. The behavior of polivalent fission products was studied. The R-AMP column was applied to separate cesium from irradiated uranium solutions [pt

Potentiality of Acidithiobacillus thiooxidans in Microbial Solubilization of Phosphate Mine Tailings

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S Dhakar

2015-04-01

Full Text Available This paper deals with the solubilization behavior of the tailings produced by the floatation of a complex low grade phosphate ore. The composition of the tailings was essentially dolomite (52.04% with minor amounts of phosphate, iron and aluminium oxides (10.4 and 0.5% respectively. The presence of these products created uncontrolled land pollution and severely affected groundwater. An initiative has been taken up for utilization of this waste to generate an eco-friendly product. First step towards this panorama is incorporation of suitable microorganisms for the biodegradation of this effluent. Sulphur oxidizing bacteria Acidithiobacillus thiooxidans produces sulphuric acid which neutralizes the dolomitic tailings and convert it into plant available forms. The solubilization activity was tested in sulphur medium with 5, 10, 15 and 20% concentration of tailings. The solubilization is graded on the basis of pH, Electrical conductivity (EC, soluble calcium and magnesium and soluble phosphate. The results from ex-situ experiments showed that the treatment with 15% tailings ended with highest solubilization. The values of pH, EC, soluble calcium and magnesium and soluble phosphate for this treatment were 4.92, 31.6 dS/m, 10.8 mL EDTA and 17.24 µg/mL respectively. Also, the results proved that sulphur oxidizing bacteria Acidithiobacillus thiooxidans is capable of solubilizing dolomitic tailings from the Jhamarkotra mines. Finally, an important factor taken into account was solubilization of residual phosphate along with dolomite in the tailings. This combined action affects the solubilization behaviour of the residue, which was also showed successfully with the assayed laboratory studies.

Effect of Pyrite on Thiosulfate Leaching of Gold and the Role of Ammonium Alcohol Polyvinyl Phosphate (AAPP

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Xiaoliang Liu

2017-07-01

Full Text Available The effect of pyrite and the role of ammonium alcohol polyvinyl phosphate (AAPP during gold leaching in ammoniacal thiosulfate solutions were investigated using pure gold foils. The results showed that pyrite catalyzed the decomposition and also significantly increased the consumption of thiosulfate. This detrimental effect became more severe with increasing pyrite content. Further, the presence of pyrite also substantially slowed the gold leaching kinetics and reduced the overall gold dissolution. The reduction in gold dissolution was found to be caused primarily by the surface passivation of the gold. The negative effects of pyrite, however, can be alleviated by the addition of AAPP. Comparison of zeta potentials of pyrite with and without AAPP suggests that AAPP had adsorbed on the surface of the pyrite and weakened the catalytic effect of pyrite on the thiosulfate decomposition by blocking the contact between the pyrite and thiosulfate anions. AAPP also competed with thiosulfate anions to complex with the cupric ion at the axial coordinate sites, and thus abated the oxidation of thiosulfate by cupric ions. Moreover, the indiscriminate adsorption of AAPP on the surfaces of gold and passivation species prevented the passivation of the gold surface by surface charge and electrostatic repulsion. Therefore, AAPP effectively stabilized the thiosulfate in the solution and facilitated the gold leaching in the presence of pyrite.

Magnesium substitution in brushite cements for enhanced bone tissue regeneration

Energy Technology Data Exchange (ETDEWEB)

Cabrejos-Azama, Jatsue, E-mail: jacaza@farm.ucm.es [Departamento de Química-Física II, Facultad de Farmacia, UCM, Madrid (Spain); Departamento de Estomatología III, Facultad de Odontología UCM, Madrid (Spain); Alkhraisat, Mohammad Hamdan; Rueda, Carmen [Departamento de Química-Física II, Facultad de Farmacia, UCM, Madrid (Spain); Torres, Jesús [Facultad de Ciencias de la salud URJC, Alcorcón, Madrid (Spain); Blanco, Luis [Departamento de Estomatología III, Facultad de Odontología UCM, Madrid (Spain); López-Cabarcos, Enrique [Departamento de Química-Física II, Facultad de Farmacia, UCM, Madrid (Spain)

2014-10-01

We have synthesized calcium phosphate cements doped with different amounts of magnesium (Mg-CPC) with a twofold purpose: i) to evaluate in vitro the osteoblast cell response to this material, and ii) to compare the bone regeneration capacity of the doped material with a calcium cement prepared without magnesium (CPC). Cell proliferation and in vivo response increased in the Mg-CPCs in comparison with CPC. The Mg-CPCs have promoted higher new bone formation than the CPC (p < 0.05). The cytocompatibility and histomorfometric analysis performed in the rabbit calvaria showed that the incorporation of magnesium ions in CPC improves osteoblasts proliferation and provides higher new bone formation. The development of a bone substitute with controllable biodegradable properties and improved bone regeneration can be considered a step toward personalized therapy that can adapt to patient needs and clinical situations. - Highlights: • The Mg-CPCs promote higher new bone formation than the CPC. • The incorporation of magnesium ions in CPC improves osteoblasts proliferation. • Mg-CPC is a bone substitute with controllable biodegradable properties. • We suggest that the use of Mg ions could improve the clinical efficiency of CPCs.

Determination of ammonium on an integrated microchip with LED-induced fluorescence detection.

Science.gov (United States)

Xue, Shuhua; Uchiyama, Katsumi; Li, Hai-Fang

2012-01-01

A simply fabricated microfluidic device integrated with a fluorescence detection system has been developed for on-line determination of ammonium in aqueous samples. A 365-nm light-emitting diode (LED) as an excitation source and a minor band pass filter were mounted into a polydimethylsiloxane (PDMS)-based microchip for the purpose of miniaturization of the entire analytical system. The ammonium sample reacted with o-phthaldialdehyde (OPA) on-chip with sodium sulfite as reducing reagent to produce a fluorescent isoindole derivative, which can emit fluorescence signal at about 425 nm when excited at 365 nm. Effects of pH, flow rate of solutions, concentrations of OPA-reagent, phosphate and sulfite salt were investigated. The calibration curve of ammonium in the range of 0.018-1.8 microg/mL showed a good linear relationship with R2 = 0.9985, and the detection limit was (S/N = 3) 3.6 x 10(-4) microg/mL. The relative standard deviation was 2.8% (n = 11) by calculating at 0.18 microg/mL ammonium for repeated detection. The system was applied to determine the ammonium concentration in rain and river waters, even extent to other analytes fluorescence detection by the presented device.

Effect of bicarbonate on biodegradation behaviour of pure magnesium in a simulated body fluid

International Nuclear Information System (INIS)

Li, Zaichun; Song, Guang-Ling; Song, Shizhe

2014-01-01

The effect of bicarbonate on biodegradation of pure magnesium in a simulated body fluid is investigated by means of X-ray diffraction, X-ray photoelectron spectroscopy, polarization curve and electrochemical impedance spectroscopy. The results show that magnesium biodegrades rapidly and non-uniformly during 27 h of immersion in four simulated body fluid solutions containing different concentrations of bicarbonate. The biodegradation rate first decreases and then increases with time. A small amount of bicarbonate in simulated body fluid has an inhibition effect on the Mg dissolution, while an overdose of bicarbonate addition activates the magnesium surface in the simulated body fluid. The interesting phenomena can be interpreted by a surface film model involving precipitation of calcium carbonate and further ionization of bicarbonate in the simulated body fluids, incorporation of calcium, carbonate and phosphate compounds in the surface film, and development of chloride-induced pitting corrosion damage on the magnesium with time

Formation of a Spinel Coating on AZ31 Magnesium Alloy by Plasma Electrolytic Oxidation

Science.gov (United States)

Sieber, Maximilian; Simchen, Frank; Scharf, Ingolf; Lampke, Thomas

2016-03-01

Plasma electrolytic oxidation (PEO) is a common means for the surface modification of light metals. However, PEO of magnesium substrates in dilute electrolytes generally leads to the formation of coatings consisting of unfavorable MgO magnesium oxide. By incorporation of electrolyte components, the phase constitution of the oxide coatings can be modified. Coatings consisting exclusively of MgAl2O4 magnesium-aluminum spinel are produced by PEO in an electrolyte containing hydroxide, aluminate, and phosphate anions. The hardness of the coatings is 3.5 GPa on Martens scale on average. Compared to the bare substrate, the coatings reduce the corrosion current density in dilute sodium chloride solution by approx. one order of magnitude and slightly shift the corrosion potential toward more noble values.

Influence of silica nanospheres on corrosion behavior of magnesium matrix syntactic foam

Science.gov (United States)

Qureshi, W.; Kannan, S.; Vincent, S.; Eddine, N. N.; Muhammed, A.; Gupta, M.; Karthikeyan, R.; Badari, V.

2018-04-01

Over the years, the development of Magnesium alloys as biodegradable implants has seen significant advancements. Magnesium based materials tend to provide numerous advantages in the field of biomedical implants over existing materials such as titanium or stainless steel. The present research focuses on corrosive behavior of Magnesium reinforced with different volume percentages of Hollow Silica Nano Spheres (HSNS). These behaviors were tested in two different simulated body fluids (SBF) namely, Hank’s Buffered Saline Solution (HBSS) and Phosphate Buffered Solution (PBS). This corrosion study was done using the method of electrochemical polarization with a three-electrode configuration. Comparative studies were established by testing pure Mg which provided critical information on the effects of the reinforcing material. The HSNS reinforced Mg displayed desirable characteristics after corrosion experiments; increased corrosion resistance was witnessed with higher volume percentage of HSNS.

Effects of Dietary Supplementation of Magnesium Hydrogen Phosphate (MgHPO as an Alternative Phosphorus Source on Growth and Feed Utilization of Juvenile Far Eastern Catfish (

Directory of Open Access Journals (Sweden)

Tae-Hyun Yoon

2014-08-01

Full Text Available The present study was conducted to investigate a supplemental effect of magnesium hydrogen phosphate (MHP, MgHPO4 as an alternative phosphorus (P source on growth and feed utilization of juvenile far eastern catfish (Silurus asotus in comparison with three conventional P additives (monocalcium phosphate (MCP, dicalcium phosphate (DCP and tricalcium phosphate [TCP] as positive controls. A basal diet as a negative control was prepared without P supplementation and four supplemental P sources were added at the level of 2%. Five groups of 450 fish having mean body weight of 11.3 g following 24 h fasting after three week adaptation period were randomly distributed into each of 15 tanks (30 fish/tank. Fish were hand-fed to apparent satiety twice a day for 8 weeks. Fish fed MHP had weight gain (WG, protein efficiency ratio and specific growth rate comparable to those fed MCP. Fish fed MHP and MCP had feed efficiency (FE significantly higher (p0.05 among treatments. Fish fed control had the lowest hematocrit, which was significantly different (p<0.05 from that of fish fed MHP. Fish fed MCP and MHP had plasma P higher (p<0.05 than fish fed the other diets. Relative efficiencies of MCP, DCP and TCP to MHP were found to be 100.5 and 101.3%, 92.0 and 91.6%, and 79.1 and 80.9% for WG and FE, respectively. P availability was determined to be 88.1%, 75.2%, 8.7%, and 90.9% for MCP, DCP, TCP, and MHP, respectively. Consequently, MHP recovered from wastewater stream showed that as an alternative P source its performance was comparative with MCP on growth and feed utilization of juvenile far eastern catfish.

Overexpression, crystallization and preliminary X-ray crystallographic analysis of erythronate-4-phosphate dehydrogenase from Pseudomonas aeruginosa.

Science.gov (United States)

Ha, Jun Yong; Lee, Ji Hyun; Kim, Kyoung Hoon; Kim, Do Jin; Lee, Hyung Ho; Kim, Hye-Kyung; Yoon, Hye-Jin; Suh, Se Won

2006-02-01

The enzyme erythronate-4-phosphate dehydrogenase catalyses the conversion of erythronate-4-phosphate to 3-hydroxy-4-phospho-hydroxy-alpha-ketobutyrate. It belongs to the D-isomer-specific 2-hydroxyacid dehydrogenase family. It is essential for de novo biosynthesis of vitamin B6 (pyridoxine). Erythronate-4-phosphate dehydrogenase from Pseudomonas aeruginosa, a homodimeric enzyme consisting of two identical 380-residue subunits, has been overexpressed in Escherichia coli with a C-terminal purification tag and crystallized at 297 K using 0.7 M ammonium dihydrogen phosphate, 0.4 M ammonium tartrate, 0.1 M sodium citrate pH 5.6 and 10 mM cupric chloride. X-ray diffraction data were collected to 2.20 A from a crystal grown in the presence of NADH. The crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 84.77, b = 101.28, c = 142.58 A. A dimeric molecule is present in the asymmetric unit, giving a crystal volume per protein weight (VM) of 3.64 A3 Da(-1) and a solvent content of 66%.

Use of fractional factorial design for selection of nutrients for culturing Paecilomyces variotii in eucalyptus hemicellulosic hydrolysate

Directory of Open Access Journals (Sweden)

J.B. Almeida e Silva

1998-09-01

Full Text Available A eucalyptus hemicellulose fraction was hydrolysed by treating eucalyptus wood chips with sulfuric acid. The hydrolysate was used as the substrate to grow Paecilomyces variotii IOC-3764 cultured for 72 or 96 hours. The influence of the inhibitors, nutrients and fermentation time was verified by a 28-4 and, subsequently, a 25-1 fractional factorial design. The effects of the inhibitors (acetic acid and furfural, nutrients (rice bran, urea, potassium nitrate, ammonium sulfate, magnesium sulfate and sodium phosphate and fermentation time were investigated. The highest yield (10.59 g/L of biomass was obtained when the microorganisms were cultivated for 72 hours in a medium composed of 30 g/L rice bran, 9.4 g/L ammonium sulfate (2 g/L nitrogen and 2 g/L sodium phosphate.

Deleterious effects of magnesium intoxication upon the domestic broiler chick

Energy Technology Data Exchange (ETDEWEB)

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.

Oxide films on magnesium and magnesium alloys

International Nuclear Information System (INIS)

Shih, T.-S.; Liu, J.-B.; Wei, P.-S.

2007-01-01

Magnesium alloys are very active and readily ignite during heating and melting. In this study, we discuss the combustion of magnesium and magnesium alloys and propose prospective anti-ignition mechanisms for magnesium alloys during the heating process. When magnesium and magnesium alloys were heated in air, the sample surfaces produced layers of thermally formed oxides. These thermally formed oxides played an important role in affecting the combustion of the magnesium and magnesium alloys. When magnesium was heated in air, brucite that formed in the early stage was then transformed into periclase by dehydroxylation. By extending the heating time, more periclase formed and increased in thickness which was associated with microcracks formation. When magnesium was heated in a protective atmosphere (SF 6 ), a film of MgF 2 formed at the interface between the oxide layer and the Mg substrate. This film generated an anti-ignition behavior which protected the substrate from oxidation. When solution-treated AZ80 alloy was heated, spinel developed at the interface between the thermally formed oxide layer and the Mg substrate, improving the anti-ignition properties of the substrate. In addition, we also explain the effects of beryllium in an AZB91 alloy on the ignition-proofing behavior

The Properties of Ammonium Dinitramine (ADN): Part 2: Melt Casting

Science.gov (United States)

Hahma, A.; Edvinsson, H.; Östmark, H.

2010-04-01

A melt casting technique for ammonium dinitramine (ADN) and ADN/aluminum was developed. ADN proved relatively easy to cast, when 1% of magnesium oxide was used as a stabilizer and crystallization kernels. Densities of ADN/MgO 99/1 were 92 to 97% of theoretical mean density (TMD) and those of ADN/Al/MgO 64/35/1 were between 95 and 99% of TMD. Sedimentation of Al in the melt was prevented and the particle wetting was ensured by selecting a suitable particle size for Al. No gelling agents or other additives were used. The casting process and factors influencing it are discussed.

Evaluation of Musa (Paradisiaca Linn. cultivar)--"Puttubale" stem juice for antilithiatic activity in albino rats.

Science.gov (United States)

Prasad, K V; Bharathi, K; Srinivasan, K K

1993-10-01

The fresh juice of Musa stem (Puttubale) was tested for its antilithiatic activity. Zinc discs were implanted in the urinary bladder of albino rats to induce urolithiasis. The stones formed were mainly of magnesium ammonium phosphate with traces of calcium oxalate. Musa stem juice (3 mL/rat/day orally) was found to be effective in reducing the formation and also in dissolving the pre-formed stones.

Vaginal Calculus in a Woman With Mixed Urinary Incontinence and Vaginal Mesh Exposure.

Science.gov (United States)

Winkelman, William D; Rabban, Joseph T; Korn, Abner P

2016-01-01

Vaginal calculi are extremely rare and are most commonly encountered in the setting of an urethrovaginal or vesicovaginal fistula. We present a case of a 72-year-old woman with mixed urinary incontinence and vaginal mesh exposure incidentally found to have a large vaginal calculus. We removed the calculus surgically and analyzed the components. Results demonstrated the presence of ammonium-magnesium phosphate hexahydrate and carbonate apatite.

A regenerable potassium and phosphate sorbent system to enhance dialysis efficacy and device portability: an in vitro study.

Science.gov (United States)

Wester, Maarten; Simonis, Frank; Gerritsen, Karin G; Boer, Walther H; Wodzig, Will K; Kooman, Jeroen P; Joles, Jaap A

2013-09-01

Continuous dialysis could provide benefit by constant removal of potassium and phosphate. This study investigates the suitability of specific potassium and phosphate sorbents for incorporation in an extracorporeal device by capacity and regenerability testing. Capacity testing was performed in uraemic plasma. Regenerability was tested for potassium sorbents, with adsorption based on cationic exchange for sodium, with 0.1 M and 1.0 M NaCl. To regenerate phosphate sorbents, with adsorption based on anionic exchange, 0.1 M and 1.0 M NaHCO3 and NaOH were used. Subsequently, sodium polystyrene divinylbenzene sulphonate (RES-A) and iron oxide hydroxide (FeOOH) beads were incorporated in a cartridge for testing in bovine blood using a recirculating blood circuit and a dialysis circuit separated by a high-flux dialyzer (dynamic setup). Preloading was tested to assess whether this could limit calcium and magnesium adsorption. In the batch-binding assays, zirconium phosphate most potently adsorbed potassium (0.44 ± 0.05 mmol/g) and RES-A was the best regenerable potassium sorbent (92.9 ± 5.7% with 0.1 M NaCl). Zirconium oxide hydroxide (ZIR-hydr) most potently adsorbed phosphate (0.23 ± 0.05 mmol/g) and the polymeric amine sevelamer carbonate was the best regenerable sorbent (85.7 ± 5.2% with 0.1 M NaHCO3). In the dynamic setup, a potassium adsorption of 10.72 ± 2.06 mmol in 3 h was achieved using 111 g of RES-A and a phosphate adsorption of 4.73 ± 0.53 mmol in 3 h using 55 g of FeOOH. Calcium and magnesium preloading was shown to reduce the net adsorption in 3 h from 3.57 ± 0.91 to -0.29 ± 1.85 and 1.02 ± 0.05 to -0.31 ± 0.18 mmol, respectively. RES-A and FeOOH are suitable, regenerizable sorbents for potassium and phosphate removal in dialysate regeneration. Use of zirconium carbonate and ZIR-hydr may further increase phosphate adsorption, but may compromise sorbent regenerability. Use of polymeric amines for phosphate adsorption may enhance sorbent

Overexpression, crystallization and preliminary X-ray crystallographic analysis of erythronate-4-phosphate dehydrogenase from Pseudomonas aeruginosa

Energy Technology Data Exchange (ETDEWEB)

Ha, Jun Yong; Lee, Ji Hyun; Kim, Kyoung Hoon; Kim, Do Jin; Lee, Hyung Ho; Kim, Hye-Kyung; Yoon, Hye-Jin; Suh, Se Won, E-mail: sewonsuh@snu.ac.kr [Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 151-742 (Korea, Republic of)

2006-02-01

Erythronate-4-phosphate dehydrogenase from P. aeruginosa was crystallized and X-ray diffraction data were collected to 2.20 Å resolution. The enzyme erythronate-4-phosphate dehydrogenase catalyses the conversion of erythronate-4-phosphate to 3-hydroxy-4-phospho-hydroxy-α-ketobutyrate. It belongs to the d-isomer-specific 2-hydroxyacid dehydrogenase family. It is essential for de novo biosynthesis of vitamin B{sub 6} (pyridoxine). Erythronate-4-phosphate dehydrogenase from Pseudomonas aeruginosa, a homodimeric enzyme consisting of two identical 380-residue subunits, has been overexpressed in Escherichia coli with a C-terminal purification tag and crystallized at 297 K using 0.7 M ammonium dihydrogen phosphate, 0.4 M ammonium tartrate, 0.1 M sodium citrate pH 5.6 and 10 mM cupric chloride. X-ray diffraction data were collected to 2.20 Å from a crystal grown in the presence of NADH. The crystals belong to the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 84.77, b = 101.28, c = 142.58 Å. A dimeric molecule is present in the asymmetric unit, giving a crystal volume per protein weight (V{sub M}) of 3.64 Å{sup 3} Da{sup −1} and a solvent content of 66%.

Overexpression, crystallization and preliminary X-ray crystallographic analysis of erythronate-4-phosphate dehydrogenase from Pseudomonas aeruginosa

International Nuclear Information System (INIS)

Ha, Jun Yong; Lee, Ji Hyun; Kim, Kyoung Hoon; Kim, Do Jin; Lee, Hyung Ho; Kim, Hye-Kyung; Yoon, Hye-Jin; Suh, Se Won

2006-01-01

Erythronate-4-phosphate dehydrogenase from P. aeruginosa was crystallized and X-ray diffraction data were collected to 2.20 Å resolution. The enzyme erythronate-4-phosphate dehydrogenase catalyses the conversion of erythronate-4-phosphate to 3-hydroxy-4-phospho-hydroxy-α-ketobutyrate. It belongs to the d-isomer-specific 2-hydroxyacid dehydrogenase family. It is essential for de novo biosynthesis of vitamin B 6 (pyridoxine). Erythronate-4-phosphate dehydrogenase from Pseudomonas aeruginosa, a homodimeric enzyme consisting of two identical 380-residue subunits, has been overexpressed in Escherichia coli with a C-terminal purification tag and crystallized at 297 K using 0.7 M ammonium dihydrogen phosphate, 0.4 M ammonium tartrate, 0.1 M sodium citrate pH 5.6 and 10 mM cupric chloride. X-ray diffraction data were collected to 2.20 Å from a crystal grown in the presence of NADH. The crystals belong to the orthorhombic space group P2 1 2 1 2 1 , with unit-cell parameters a = 84.77, b = 101.28, c = 142.58 Å. A dimeric molecule is present in the asymmetric unit, giving a crystal volume per protein weight (V M ) of 3.64 Å 3 Da −1 and a solvent content of 66%

Enhancement of struvite pellets crystallization in a full-scale plant using an industrial grade magnesium product.

Science.gov (United States)

Crutchik, D; Morales, N; Vázquez-Padín, J R; Garrido, J M

2017-02-01

A full-scale struvite crystallization system was operated for the treatment of the centrate obtained from the sludge anaerobic digester in a municipal wastewater treatment plant. Additionally, the feasibility of an industrial grade Mg(OH) 2 as a cheap magnesium and alkali source was also investigated. The struvite crystallization plant was operated for two different periods: period I, in which an influent with low phosphate concentration (34.0 mg P·L -1 ) was fed to the crystallization plant; and period II, in which an influent with higher phosphate concentration (68.0 mg P·L -1 ) was used. A high efficiency of phosphorus recovery by struvite crystallization was obtained, even when the effluent treated had a high level of alkalinity. Phosphorus recovery percentage was around 77%, with a phosphate concentration in the effluent between 10.0 and 30.0 mg P·L -1 . The experiments gained struvite pellets of 0.5-5.0 mm size. Moreover, the consumption of Mg(OH) 2 was estimated at 1.5 mol Mg added·mol P recovered -1 . Thus, industrial grade Mg(OH) 2 can be an economical alternative as magnesium and alkali sources for struvite crystallization at industrial scale.

Improving the packing density of calcium phosphate coating on a magnesium alloy for enhanced degradation resistance.

Science.gov (United States)

Kannan, M Bobby

2013-05-01

In this study, an attempt was made to improve the packing density of calcium phosphate (CaP) coating on a magnesium alloy by tailoring the coating solution for enhanced degradation resistance of the alloy for implant applications. An organic solvent, ethanol, was added to the coating solution to decrease the conductivity of the coating solution so that hydrogen bubble formation/bursting reduces during the CaP coating process. Experimental results confirmed that ethanol addition to the coating solution reduces the conductivity of the solution and also decreases the hydrogen evolution/bubble bursting. In vitro electrochemical experiments, that is, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization showed that CaP coating produced in 30% (v/v) ethanol containing coating solution (3E) exhibits significantly higher degradation resistance (i.e., ~50% higher polarization resistance and ~60% lower corrosion current) than the aqueous solution coating. Scanning electron microscope (SEM) analysis of the coatings revealed that the packing of 3E coating was denser than that of aqueous coating, which can be attributed to the lower hydrogen evolution in the former than in the latter. Further increase in the ethanol content in the coating solution was not beneficial; in fact, the coating produced in 70% (v/v) ethanol containing solution (7E) showed degradation resistance much inferior to that of the aqueous coating, which is due to low thickness of 7E coating. Copyright © 2012 Wiley Periodicals, Inc.

Effect of sintering conditions on the microstructural and mechanical characteristics of porous magnesium materials prepared by powder metallurgy.

Science.gov (United States)

Čapek, Jaroslav; Vojtěch, Dalibor

2014-02-01

There has recently been an increased demand for porous magnesium materials in many applications, especially in the medical field. Powder metallurgy appears to be a promising approach for the preparation of such materials. Many works have dealt with the preparation of porous magnesium; however, the effect of sintering conditions on material properties has rarely been investigated. In this work, we investigated porous magnesium samples that were prepared by powder metallurgy using ammonium bicarbonate spacer particles. The effects of the purity of the argon atmosphere and sintering time on the microstructure (SEM, EDX and XRD) and mechanical behaviour (universal loading machine and Vickers hardness tester) of porous magnesium were studied. The porosities of the prepared samples ranged from 24 to 29 vol.% depending on the sintering conditions. The purity of atmosphere played a significant role when the sintering time exceeded 6h. Under a gettered argon atmosphere, a prolonged sintering time enhanced diffusion connections between magnesium particles and improved the mechanical properties of the samples, whereas under a technical argon atmosphere, oxidation at the particle surfaces caused deterioration in the mechanical properties of the samples. These results suggest that a refined atmosphere is required to improve the mechanical properties of porous magnesium. © 2013.

Antibacterial and remineralizing orthodontic adhesive containing quaternary ammonium resin monomer and amorphous calcium phosphate nanoparticles.

Science.gov (United States)

Liu, Yan; Zhang, Ling; Niu, Li-Na; Yu, Tao; Xu, Hockin H K; Weir, Michael D; Oates, Thomas W; Tay, Franklin R; Chen, Ji-Hua

2018-05-01

To evaluate the bonding performance, antibacterial activity, and remineralization effect on enamel of the orthodontic adhesive containing MAE-DB and NACP. Eighty non-carious human premolars were divided into 3 groups: Transbond XT (TB), PEHB + 5% MAE-DB (PD), and PEHB + 40% NACP + 5% MAE-DB (PND). Premolars were bonded with orthodontic brackets, the first subgroup (n = 10) and the second subgroup (n = 10) were subjected to shear bond strength testing after immersed in water for 1 day and in demineralization solution for 28 days respectively and then tested surface roughness, while the third subgroup (n = 6) was used for microhardness evaluation after aged in demineralization solution for 28 days. For each adhesive, fifty disk samples were prepared for antibacterial study. Specimens measuring 12 mm × 2 mm × 2 mm were fabricated for ion release test. Bond strengths were in the order TB = PND > PND = PD for "1-day in water", and in the order TB = PND > PD for "28-days in pH 4 solution". No significant difference in the ARI scores for the three adhesive. Numerous bacteria adhered to TB surface, while PD and PND had minimal bacterial growth and activity. PND showed high levels of Ca and P ions release and enamel hardness. The surface roughness of enamel in PND was much lower than TB and PD and showed no significant difference with the sound, control enamel. PND adhesive with 5% MAE-DB and 40% NACP exhibits antibacterial and remineralizing capabilities, and did not adversely affect bond strength compared to commercial adhesive. Novel adhesive containing quaternary ammonium monomer and nano-amorphous calcium phosphate represents a promising candidate in combating enamel white spot lesions and even dental caries. Copyright © 2018 Elsevier Ltd. All rights reserved.

Kinetics Modeling and Isotherms for Adsorption of Phosphate from Aqueous Solution by Modified Clinoptilolit

Directory of Open Access Journals (Sweden)

Mohammad Malakootian

2012-01-01

Full Text Available The Phosphorous discharge into the surface water led to excessive growth of algae and eutrophication in lakes and rivers. Therefore the phosphorus removal is important due to negative effect on water resources. The aim of this study was to investigat the modification of clinoptilolite and application of modified clinoptilolite for phosphorous adsorption from aqueous solution and isotherms and kinetics modeling. Hexadecyl Trimethyl Ammonium bromide (HDTMA-Br, Hexadecyl trimethyl Ammonium Chloride (HDTMA-Cl, Sodium Decyl Sulphate (SDS and Cetrimide-C were used for modification of clinoptilolite. Experiments were conducted using jar apparatus and batch system. The effect of pH, adsorbent doses, contact time, phosphate initial concentration and particle size were studied surveyed on phosphate adsorption by modified clinoptilolite. The most common isotherms and the kinetics adsorption equations were used for determination of adsorption rate and dynamic reaction. The results showed that maximum phosphate adsorption was obtained in the pH of 7 and contact time 90min. Also it was found with the increasing of phosphate initial concentration, phosphate removal efficiency decreased significantly. Langmuir No 2 showed a good correlation compared to other isotherms (R2=0.997. Maximum adsorption capacity was obtained in 20g/L adsorbent dose (22.73mg/g. Also Interaparticle diffusion kinetics well fits with experimental data (R2=0.999 with constant rate of 3.84mg/g min0.5. The result showed that modified clinoptilolite can be used successfully as low cost and effective absorbent for phosphate removal.

Effects of phosphate addition on methane fermentation in the batch and upflow anaerobic sludge blanket (UASB) reactors.

Science.gov (United States)

Suzuki, Sho; Shintani, Masaki; Sanchez, Zoe Kuizon; Kimura, Kohei; Numata, Mitsuru; Yamazoe, Atsushi; Kimbara, Kazuhide

2015-12-01

Ammonia inhibition of methane fermentation is one of the leading causes of failure of anaerobic digestion reactors. In a batch anaerobic digestion reactor with 429 mM NH3-N/L of ammonia, the addition of 25 mM phosphate resulted in an increase in methane production rate. Similar results were obtained with the addition of disodium phosphate in continuous anaerobic digestion using an upflow anaerobic sludge blanket (UASB) reactor. While methane content and production rate decreased in the presence of more than 143 mM NH3-N/L of ammonium chloride in UASB, the addition of 5 mM disodium phosphate suppressed ammonia inhibition at 214 mM NH3-N/L of ammonium chloride. The addition prevented acetate/propionate accumulation, which might be one of the effects of the phosphate on the ammonia inhibition. The effects on the microbial community in the UASB reactor was also assessed, which was composed of Bacteria involved in hydrolysis, acidogenesis, acetogenesis, and dehydrogenation, as well as Archaea carrying out methanogenesis. The change in the microbial community was observed by ammonia inhibition and the addition of phosphate. The change indicates that the suppression of ammonia inhibition by disodium phosphate addition could stimulate the activity of methanogens, reduce shift in bacterial community, and enhance hydrogen-producing bacteria. The addition of phosphate will be an important treatment for future studies of methane fermentation.

Conditions promoting and restraining agronomic effectiveness of water-insoluble phosphate sources, in particular phosphate rock (PR): I. Indices of phosphate rock use opportunity (PRUOIS) and of phosphate rock suitability for direct use (PRSIDU)

International Nuclear Information System (INIS)

Borlan, Z.; Gavriluta, I.; Soare, M.; Stefanescu, D.; Alexandrescu, A.

2002-01-01

Several issues of phosphate rock (PR) use are discussed in this paper. Maize for green fodder (Zea mays L) and ryegrass (Lolium multiflorum Lam.) were grown in 7 kg of dry soil and in small pots of 1.25 kg dry soil capacity, respectively, on several base unsaturated soils belonging to Hapludoll and Hapludalf soil groups. The amount of phosphate rock (PR) to apply was based on experimental data considering soil adsorbed acidity (Ah), humus content (H 2 ), cation exchange capacity (T), sum of exchangeable bases (SEB) and mobile (easily soluble) phosphate content (P A L) in the soil. The factors were combined in a rock phosphate use, opportunity index of the soil (PRUOIS): PRUOIS=(A h *H 2 *100)/SEB*10 0.0245*P AL Rock phosphate suitability for direct use was evaluated by means of the rate of PR-P dissolution (PRPRS) in a 0.6% ammonium heptamolybdate in 0.01M calcium chloride solution (ppm P) and by carbonate content (%CaCO 3 ) in PR. Both of these parameters combined provided a phosphate rock suitability index for direct use (PRSIDU): PRSIDU [ppmP/min]=PRPRS*(1-0.03*CaCO 3 ) Water insoluble P sources studied were PR from Kola-Russia, Morocco, Kneifiss-Siria, El Hassa-Jordan, Gafsa- Tunisia, North-Carolina (USA), and Arad-Israel. All PRs were compared with TSP applied at the same rate of P. Neither PRUOIS or PRSIDU considered separately could satisfactorily explain the variance of PR efficiency. An index obtained by multiplicative combination of PRUOIS x PRSIDU did correlate significantly with indices on the agronomic efficiency of PR. (author)

Magnesium Gluconate

Science.gov (United States)

Magnesium gluconate is used to treat low blood magnesium. Low blood magnesium is caused by gastrointestinal disorders, prolonged vomiting or ... disease, or certain other conditions. Certain drugs lower magnesium levels as well.This medication is sometimes prescribed ...

Controlling the Biodegradation of Magnesium Implants Through Nanostructured Calcium-Phosphate Coating

Science.gov (United States)

Iskandar, Maria Emil

Magnesium (Mg) alloys, a novel class of degradable, metallic biomaterials, have attracted growing interest as a promising alternative for medical implant and device applications due to their advantageous mechanical and biological properties. Moreover, Mg is biodegradable in the physiological environments. However, the major obstacle for Mg to be used as medical implants is its rapid degradation in physiological fluids. Therefore, the present key challenge lies in controlling Mg degradation rate in the physiological environment. The objective of this study was to develop a nanostructured-hydroxyapatite (nHA) coating on polished Mg implants to control the degradation and bone tissue integration of the implants. The nHA coatings were deposited on Mg using the Spire's patented TPA process to moderate the aggressive degradation of Mg and to improve quick osteointegration between Mg and natural bone. Nanostructured-HA coatings mimic the nanostructure and chemistry of natural bone, which will provide a desirable environment for bone tissue regeneration. Surface morphology, element compositions, and crystal structures were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and x-ray diffractometry (XRD), respectively. SEM images of the deposited nHA-coating was analyzed using ImageJ's quantitative image analysis tool, to determine the nHA-coating particle size and thickness. The degradation of nHA-coated and non-coated Mg samples was investigated by incubating samples in phosphate buffered saline (PBS) and revised simulated body fluid (r-SBF), under standard cell culture conditions. To mimic the in vivo cell response in the physiological environment, rat bone marrow stromal cells (BMSC) were harvested and cultured with nHA-coated and non-coated polished Mg samples to determine cytocompatibilty. The degradation results suggested that the nanocoatings positively mediated Mg degradation. It can therefore be concluded that n

Perlite as a carrier of phosphate-accumulating bacteria

International Nuclear Information System (INIS)

Ivankovic, T.; Hrenovic, J.; Sekovanic, L.; Tofant, A.

2009-01-01

The phosphate (P)-accumulating bacteria are important for biological P removal from wastewater. Currently, attention is being drawn to the immobilisation of desired bacteria on different carriers in order to achieve a better efficiency of the wastewater treatment. In this study, two size fractions (0.1-1 and 0.1-2 mm) of different forms of expanded perlite (original, autoclaved and magnesium-exchanged) were investigates as possible carriers of P accumulating bacterium. (Author)

Neutron activation analysis of urinary calculi

International Nuclear Information System (INIS)

Souka, N.; Souka, S.; Sanad, W.; Abdel-Rassoul, A.A.

1974-01-01

Urinary calculi resulting from disorders in the urinary system are mostly composed of uric acid, urates, calcium oxalate, alkaline earth phosphates (Ca and Mg), triple phosphate (magnesium ammonium phosphate), calcium carbonate, cystine, xanthine, and traces of proteins. The determination of these macro-constituents has been carried out by different analytical procedures. No attempts however, have been reported regarding the determination of trace elements in urinary stones, apart from that of Herring et al., who investigated the consumption of strontium by urolithiasis patients. The present work is a non-destructive neutron activation analysis of urinary calculi, to search the variation in concentration of certain trace elements with the chemical composition of the calculus

Fatores de retardamento e coeficientes de dispersão-difusão de fosfato, potássio e amônio em solos de Minas Gerais Retardation factors and dispersion-diffusion coefficients of phosphate, potassium and ammonium in soils of Minas Gerais - Brazil

Directory of Open Access Journals (Sweden)

Ermelinda M. M. Oliveira

2004-12-01

Full Text Available Através deste estudo objetivou-se comparar os fatores de retardamento (R e os coeficientes de dispersão-difusão (D do fosfato, potássio e amônio, determinados em cinco solos de Minas Gerais (um Neossolo Quartzarênico órtico - RQo; três Latossolos Vermelhos distróficos - LVd1, LVd2 e LVd3; e um Latossolo Vermelho-Amarelo distrófico - LVAd. O experimento foi realizado utilizando-se colunas de percolação, que receberam aplicações de uma das soluções resultantes das oito possíveis combinações de duas concentrações de fosfato, potássio e amônio (15 e 60 mg L-1 de P, 75 e 300 mg L-1 de K e 15 e 60 mg L-1 de N. Valores menores de R para o potássio e o amônio, foram observados, quando comparados com os do fosfato. O R para fosfato foi menor no solo mais arenoso (RQo e maior no mais oxídico (LVd2, enquanto nos Latossolos os maiores valores do R para potássio e amônio estiveram relacionados com o incremento do teor de argila, sem tendência definida quanto á concentração do íon em estudo ou do íon acompanhante. Não se evidenciou relação nítida entre as concentrações de fosfato, potássio e amônio e os D desses íons nos solos estudados.The objective of this study was to compare the retardation factors (R, and dispersion-diffusion coefficients (D of phosphate, potassium and ammonium, determined in five Brazilian soils from Minas Gerais State (Orthic Quartzarenic Neosoil, RQo; three distrophic Red Latosols, LVd1, LVd2 and LVd3; and a distrophic Yellow-Red Latosol, LVAd. The experiment used percolation columns, applying one of the eight possible solutions resulting from the mixture of two phosphate, potassium and ammonium concentrations (15 and 60 mg L-1 P, 75 and 300 mg L-1 K, and 15 and 60 mgL-1 N. Lower values of R were observed for potassium and ammonium compared to phosphate. The value of R for phosphate was the lowest in the most sandy soil (RQo and highest in the most oxidic soil (LVd2. The highest Latosol

Overexpression, crystallization and preliminary X-­ray crystallographic analysis of erythronate-4-phosphate dehydrogenase from Pseudomonas aeruginosa

Science.gov (United States)

Ha, Jun Yong; Lee, Ji Hyun; Kim, Kyoung Hoon; Kim, Do Jin; Lee, Hyung Ho; Kim, Hye-Kyung; Yoon, Hye-Jin; Suh, Se Won

2006-01-01

The enzyme erythronate-4-phosphate dehydrogenase catalyses the conversion of erythronate-4-phosphate to 3-hydroxy-4-phospho-hydroxy-α-ketobutyrate. It belongs to the d-isomer-specific 2-hydroxyacid dehydrogenase family. It is essential for de novo biosynthesis of vitamin B6 (pyridoxine). Erythronate-4-­phosphate dehydrogenase from Pseudomonas aeruginosa, a homodimeric enzyme consisting of two identical 380-residue subunits, has been overexpressed in Escherichia coli with a C-terminal purification tag and crystallized at 297 K using 0.7 M ammonium dihydrogen phosphate, 0.4 M ammonium tartrate, 0.1 M sodium citrate pH 5.6 and 10 mM cupric chloride. X-ray diffraction data were collected to 2.20 Å from a crystal grown in the presence of NADH. The crystals belong to the orthorhombic space group P212121, with unit-cell parameters a = 84.77, b = 101.28, c = 142.58 Å. A dimeric molecule is present in the asymmetric unit, giving a crystal volume per protein weight (V M) of 3.64 Å3 Da−1 and a solvent content of 66%. PMID:16511285

Use of Ferrihydrite-Coated Pozzolana and Biogenic Green Rust to Purify Waste Water Containing Phosphate and Nitrate

Energy Technology Data Exchange (ETDEWEB)

Ruby, Christian; Naille, Sébastien; Ona-Nguema, Georges; Morin, Guillaume; Mallet, Martine; Guerbois, Delphine; Barthélémy, Kévin; Etique, Marjorie; Zegeye, Asfaw; Zhang, Yuhai; Boumaïza, Hella; Al-Jaberi, Muayad; Renard, Aurélien; Noël, Vincent; Binda, Paul; Hanna, Khalil; Despas, Christelle; Abdelmoula, Mustapha; Kukkadapu, Ravi; Sarrias, Joseph; Albignac, Magali; Rocklin, Pascal; Nauleau, Fabrice; Hyvrard, Nathalie; Génin, Jean-Marie

2016-06-27

The activated sludge treatments combined to the addition of ferric chloride is commonly used to eliminate nitrate and phosphate from waste water in urban area. These processes that need costly infrastructures are not suitable for rural areas and passive treatments (lagoons, reed bed filters…) are more frequently performed. Reed bed filters are efficient for removing organic matter but are not suitable for treating phosphate and nitrate as well. Passive water treatments using various materials (hydroxyapatite, slag…) were already performed, but those allowing the elimination of both nitrate and phosphate are not actually available. The goal of this work is to identify the most suitable iron based materials for such treatments and to determine their optimal use conditions, in particular in hydrodynamic mode. The reactivity of the iron based minerals was measured either by using free particles in suspension or by depositing these particles on a solid substrate. Pouzzolana that is characterized by a porous sponge-like structure suits for settling a high amount of iron oxides. The experimental conditions enabling to avoid any ammonium formation when green rust encounters nitrate were determined within the framework of a full factorial design. The process is divided into two steps that will be performed inside two separated reactors. Indeed, the presence of phosphate inhibits the reduction of nitrate by green rust and the dephosphatation process must precede the denitrification process. In order to remove phosphate, ferrihydrite coated pouzzolana is the best materials. The kinetics of reaction of green rust with nitrate is relatively slow and often leads to the formation of ammonium. The recommendation of the identified process is to favor the accumulation of nitrite in a first step, these species reacting much more quickly with green rust and do not transform into ammonium.

Effect of low ambient mineral concentrations on the accumulation of calcium, magnesium and phosphorus by early life stages of the air-breathing armoured catfish Megalechis personata (Siluriformes; Callichthyidae)

NARCIS (Netherlands)

Mol, J.H.; Atsma, W.; Flik, G.; Bouwmeester, H.; Osse, J.W.M.

1999-01-01

he accumulation of calcium, magnesium and phosphorus was measured during an 8-week period in the early life stages of the air-breathing armoured catfish Megalechis personata acclimated to low-mineral fresh water (0.073 mmol l-1 calcium, 0.015 mmol l-1 magnesium, <0.001 mmol l-1 phosphate) and

Adsorption of ammonium and phosphate by feather protein based semi-interpenetrating polymer networks hydrogel as a controlled-release fertilizer.

Science.gov (United States)

Su, Yuan; Liu, Jia; Yue, Qinyan; Li, Qian; Gao, Baoyu

2014-01-01

A new feather protein-grafted poly(potassium acrylate)/polyvinyl alcohol (FP-g-PKA/PVA) semi-interpenetrating polymer networks (semi-IPNs) hydrogel was produced through graft copolymerization with FP as a basic macromolecular skeletal material, acrylic acid as a monomer and PVA as a semi-IPNs polymer. The adsorption of ammonium and phosphate ions from aqueous solution using the new hydrogel as N and P controlled-release fertilizer with water-retention capacity was studied. The effects of pH value, concentration, contact time and ion strength on NH4+ and PO3-4 removal by FP-g-PKA/PVA semi-IPNs hydrogel were investigated using batch adsorption experiments. The results indicated that the hydrogel had high adsorption capacities and fast adsorption rates for NH4+ and PO3-4 in wide pH levels ranging from 4.0 to 9.0. Kinetic analysis presented that both NH4+ and PO3-4 removal were closely fitted with the pseudo-second-order model. Furthermore, the adsorption isotherms of hydrogel were best represented by the Freundlich model. The adsorption-desorption experimental results showed the sustainable stability of FP-g-PKA/PVA semi-IPNs hydrogel for NH4+ and PO3-4 removal. Overall, FP-g-PKA/PVA could be considered as an efficient material for the removal and recovery of nitrogen and phosphorus with the agronomic reuse as a fertilizer.

Removal of phosphate from eutrophic lakes through adsorption by in situ formation of magnesium hydroxide from diatomite.

Science.gov (United States)

Xie, Fazhi; Wu, Fengchang; Liu, Guijian; Mu, Yunsong; Feng, Chenglian; Wang, Huanhua; Giesy, John P

2014-01-01

Since in situ formation of Mg(OH)2 can efficiently sorb phosphate (PO4) from low concentrations in the environment, a novel dispersed magnesium oxide nanoflake-modified diatomite adsorbent (MOD) was developed for use in restoration of eutrophic lakes by removal of excess PO4. Various adsorption conditions, such as pH, temperature and contact time were investigated. Overall, sorption capacities increased with increasing temperature and contact time, and decreased with increasing pH. Adsorption of PO4 was well described by both the Langmuir isotherm and pseudo second-order models. Theoretical maximum sorption capacity of MOD for PO4 was 44.44-52.08 mg/g at experimental conditions. Characterization of PO4 adsorbed to MOD by use of X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and solid state (31)P nuclear magnetic resonance revealed that electrostatic attraction, surface complexation and chemical conversion in situ were the major forces in adsorption of PO4. Mg(OH)2 formed in situ had a net positive charge on the surface of the MOD that could adsorb PO4(3-) and HPO4(2-) anion to form surface complex and gradually convert to Mg3(PO4)2 and MgHPO4. Efficiency of removal of PO4 was 90% when 300 mg MOD/L was added to eutrophic lake water. Results presented here demonstrated the potential use of the MOD for restoration of eutrophic lakes by removal of excess PO4.

Prevention of radioactive contamination in the manufacture of phosphate fertilizers; Prevencion de contaminacion radiactiva en la fabricacion de fertilizantes fosfatados

Energy Technology Data Exchange (ETDEWEB)

Romero G, E T

1996-12-31

In this work was studied the separation of uranium from the phosphate rock to decrease the level of radioactivity in the phosphate fertilizers, this prevents the redistribution of uranium in the environment. The uranium leaching conditions from phosphate rock were estimated using alkaline solutions. The changes in the natural phosphate rock after leaching were studied. The amenability to separate the uranium from phosphate rock with ammonium carbonate / bicarbonate solution was determined. The uranium extraction was approximately 40%. The leaching conditions showed high selectivity for uranium without changes in the ore structure. The bulk ore was not dissolved. (Author).

Changes in soil toxicity by phosphate-aided soil washing: effect of soil characteristics, chemical forms of arsenic, and cations in washing solutions.

Science.gov (United States)

Jho, Eun Hea; Im, Jinwoo; Yang, Kyung; Kim, Young-Jin; Nam, Kyoungphile

2015-01-01

This study was set to investigate the changes in the toxicity of arsenic (As)-contaminated soils after washing with phosphate solutions. The soil samples collected from two locations (A: rice paddy and B: forest land) of a former smelter site were contaminated with a similar level of As. Soil washing (0.5 M phosphate solution for 2 h) removed 24.5% As, on average, in soil from both locations. Regardless of soil washing, Location A soil toxicities, determined using Microtox, were greater than that of Location B and this could be largely attributed to different soil particle size distribution. With soils from both locations, the changes in As chemical forms resulted in either similar or greater toxicities after washing. This emphasizes the importance of considering ecotoxicological aspects, which are likely to differ depending on soil particle size distribution and changes in As chemical forms, in addition to the total concentration based remedial goals, in producing ecotoxicologically-sound soils for reuse. In addition, calcium phosphate used as the washing solution seemed to contribute more on the toxic effects of the washed soils than potassium phosphate and ammonium phosphate. Therefore, it would be more appropriate to use potassium or ammonium phosphate than calcium phosphate for phosphate-aided soil washing of the As-contaminated soils. Copyright © 2014 Elsevier Ltd. All rights reserved.

Production of magnesium metal

Science.gov (United States)

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.

Protective layer formation on magnesium in cell culture medium

Energy Technology Data Exchange (ETDEWEB)

Wagener, V.; Virtanen, S., E-mail: virtanen@ww.uni-erlangen.de

2016-06-01

In the past, different studies showed that hydroxyapatite (HA) or similar calcium phosphates can be precipitated on Mg during immersion in simulated body fluids. However, at the same time, in most cases a dark grey or black layer is built under the white HA crystals. This layer seems to consist as well of calcium phosphates. Until now, neither the morphology nor its influence on Mg corrosion have been investigated in detail. In this work commercially pure magnesium (cp) was immersed in cell culture medium for one, three and five days at room temperature and in the incubator (37 °C, 5% CO{sub 2}). In addition, the influence of proteins on the formation of a corrosion layer was investigated by adding 20% of fetal calf serum (FCS) to the cell culture medium in the incubator. In order to analyze the formed layers, SEM images of cross sections, X-ray Photoelectron Spectroscopy (XPS), X-ray diffraction (XRD), Energy Dispersive X-ray Spectroscopy (EDX) and Fourier Transformed Infrared Spectroscopy (FTIR) measurements were carried out. Characterization of the corrosion behavior was achieved by electrochemical impedance spectroscopy (EIS) and by potentio-dynamic polarization in Dulbecco's Modified Eagle's Medium (DMEM) at 37 °C. Surface analysis showed that all formed layers consist mainly of amorphous calcium phosphate compounds. For the immersion at room temperature the Ca/P ratio indicates the formation of HA, while in the incubator probably pre-stages to HA are formed. The different immersion conditions lead to a variation in layer thicknesses. However, electrochemical characterization shows that the layer thickness does not influence the corrosion resistance of magnesium. The main influencing factor for the corrosion behavior is the layer morphology. Thus, immersion at room temperature leads to the highest corrosion protection due to the formation of a compact outer layer. Layers formed in the incubator show much worse performances due to completely porous

Protective layer formation on magnesium in cell culture medium

International Nuclear Information System (INIS)

Wagener, V.; Virtanen, S.

2016-01-01

In the past, different studies showed that hydroxyapatite (HA) or similar calcium phosphates can be precipitated on Mg during immersion in simulated body fluids. However, at the same time, in most cases a dark grey or black layer is built under the white HA crystals. This layer seems to consist as well of calcium phosphates. Until now, neither the morphology nor its influence on Mg corrosion have been investigated in detail. In this work commercially pure magnesium (cp) was immersed in cell culture medium for one, three and five days at room temperature and in the incubator (37 °C, 5% CO_2). In addition, the influence of proteins on the formation of a corrosion layer was investigated by adding 20% of fetal calf serum (FCS) to the cell culture medium in the incubator. In order to analyze the formed layers, SEM images of cross sections, X-ray Photoelectron Spectroscopy (XPS), X-ray diffraction (XRD), Energy Dispersive X-ray Spectroscopy (EDX) and Fourier Transformed Infrared Spectroscopy (FTIR) measurements were carried out. Characterization of the corrosion behavior was achieved by electrochemical impedance spectroscopy (EIS) and by potentio-dynamic polarization in Dulbecco's Modified Eagle's Medium (DMEM) at 37 °C. Surface analysis showed that all formed layers consist mainly of amorphous calcium phosphate compounds. For the immersion at room temperature the Ca/P ratio indicates the formation of HA, while in the incubator probably pre-stages to HA are formed. The different immersion conditions lead to a variation in layer thicknesses. However, electrochemical characterization shows that the layer thickness does not influence the corrosion resistance of magnesium. The main influencing factor for the corrosion behavior is the layer morphology. Thus, immersion at room temperature leads to the highest corrosion protection due to the formation of a compact outer layer. Layers formed in the incubator show much worse performances due to completely porous structures. The

Timeline (Bioavailability) of Magnesium Compounds in Hours: Which Magnesium Compound Works Best?

Science.gov (United States)

Uysal, Nazan; Kizildag, Servet; Yuce, Zeynep; Guvendi, Guven; Kandis, Sevim; Koc, Basar; Karakilic, Aslı; Camsari, Ulas M; Ates, Mehmet

2018-04-21

Magnesium is an element of great importance functioning because of its association with many cellular physiological functions. The magnesium content of foods is gradually decreasing due to food processing, and magnesium supplementation for healthy living has become increasingly popular. However, data is very limited on the bioavailability of various magnesium preparations. The aim of this study is to investigate the bioavailability of five different magnesium compounds (magnesium sulfate, magnesium oxide, magnesium acetyl taurate, magnesium citrate, and magnesium malate) in different tissues. Following a single dose 400 mg/70 kg magnesium administration to Sprague Dawley rats, bioavailability was evaluated by examining time-dependent absorption, tissue penetration, and the effects on the behavior of the animals. Pharmacokinetically, the area under the curve calculation is highest in the magnesium malate. The magnesium acetyl taurate was found to have the second highest area under the curve calculation. Magnesium acetyl taurate was rapidly absorbed, able to pass through to the brain easily, had the highest tissue concentration level in the brain, and was found to be associated with decreased anxiety indicators. Magnesium malate levels remained high for an extended period of time in the serum. The commonly prescribed dietary supplements magnesium oxide and magnesium citrate had the lowest bioavailability when compared to our control group. More research is needed to investigate the bioavailability of magnesium malate and acetyl taurate compounds and their effects in specific tissues and on behavior.

Effects of aqueous environment on long-term durability of phosphate-bonded ceramic waste forms

International Nuclear Information System (INIS)

Singh, D.; Wagh, A.S.; Jeong, S.Y.

1996-01-01

Over the last few years, Argonne National Laboratory has been developing room-temperature-setting chemically-bonded phosphate ceramics for solidifying and stabilizing low-level mixed wastes. This technology is crucial for stabilizing waste streams that contain volatile species and off-gas secondary waste streams generated by high-temperature treatment of such wastes. Magnesium phosphate ceramic has been developed to treat mixed wastes such as ash, salts, and cement sludges. Waste forms of surrogate waste streams were fabricated by acid-base reactions between the mixtures of magnesium oxide powders and the wastes, and phosphoric acid or acid phosphate solutions. Dense and hard ceramic waste forms are produced in this process. The principal advantage of this technology is that the contaminants are immobilized by both chemical stabilization and subsequent microencapsulation of the reaction products. This paper reports the results of durability studies conducted on waste forms made with ash waste streams spiked with hazardous and radioactive surrogates. Standard leaching tests such as ANS 16.1 and TCLP were conducted on the final waste forms. Fates of the contaminants in the final waste forms were established by electron microscopy. In addition, stability of the waste forms in aqueous environments was evaluated with long-term water-immersion tests

Magnesium and Osteoporosis

Directory of Open Access Journals (Sweden)

Ferda Özdemir

2004-03-01

Full Text Available Osteoporosis (OP is a condition of bone fragility resulting from micro-architectural deterioration and decreased bone mass. OP depends on the interaction of genetic, hormonal, environmental and nutritional factors. Chronic low intakes of vitamin D and possibly magnesium, zinc, fluoride and vitamins K, B12, B6 and folic acid may predispose to osteoporosis. Magnesium is a mineral needed by every cell of your body. It helps maintain normal muscle and nerve function, keeps heart rhythm steady, and bones strong. Mg serves as co-factors for enzymes that help build bone matrix. Magnesium deficiency occurs due to excessive loss of magnesium in urine, gastrointestinal system disorders that cause a loss of magnesium or limit magnesium absorption, or a chronic low intake of magnesium. Signs of magnesium deficiency include confusion, disorientation, loss of appetite, depression, muscle contractions and cramps, tingling, numbness, abnormal heart rhythms, coronary spasm, and seizures. Magnesium deficiency alters calcium metabolism and the hormones that regulates calcium. Several studies have suggested that magnesium supplementation may improve bone mineral density and prevent fractures.

Determination of ammonium in wastewaters by capillary electrophoresis on a column-coupling chip with conductivity detection.

Science.gov (United States)

Luc, Milan; Kruk, Pavol; Masár, Marián

2011-07-01

Analytical potentialities of a chip-based CE in determination of ammonium in wastewaters were investigated. CZE with the electric field and/or ITP sample stacking was performed on a column-coupling (CC) chip with integrated conductivity detectors. Acetate background electrolytes (pH ∼3) including 18-crown-6-ether (18-crown-6) and tartaric acid were developed to reach rapid (in 7-8 min) CZE and ITP-CZE resolutions of ammonium from other cations (sodium, potassium, calcium and magnesium) present in wastewater samples. Under preferred working conditions (suppressed hydrodynamic flow (HDF) and EOF on the column-coupling chip), both the employed methods did provide very good repeatabilities of the migration (RSD of 0.2-0.8% for the migration time) and quantitative (RSD of 0.3-4.9% for the peak area) parameters in the model and wastewater samples. Using a 900-nL sample injection volume, LOD for ammonium were obtained at 20 and 40 μg/L concentrations in CZE and ITP-CZE separations, respectively. Very good agreements of the CZE and ITP-CZE determinations of ammonium in six untreated wastewater samples (only filtration and dilution) with the results obtained by a reference spectrometric method indicate a very good accuracy of both the CE methods presented. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Regeneration of clinoptilolite zeolite used for the ammonium removal

International Nuclear Information System (INIS)

Garcia G, M.C.

2002-01-01

The use of zeolites has been increased in the last years with different applications and with a great boom in the environmental area, but a little had been make about the regeneration of such zeolites. The presence of nitrogen-ammonia in water may cause serious pollution problems since it results to be toxic for fishes and other aquatic life forms, also it provokes the algae growing. The natural clinoptilolite contains interchangeable ions such as the sodium (Na + ), potassium (K + ), magnesium (Mg 2+ ) and calcium (Ca 2+ ) in different proportions depending on the mineral origin When the zeolite is upgraded to its sodium form, the cation exchange capacity and the preference by the nitrogen-ammonia are increased, allowing the reversible process of sorption. In this work it was proposed the regeneration to its sodium form about the ammonia clinoptilolite zeolite. The natural mineral was characterized using the methods such as: X-ray diffraction, Infrared spectroscopy, Thermal gravimetric analysis and surface area. The results show that the ammonium sorption was between 95% and 98.7% such an ambient temperature as a flow back. the zeolite was regenerated approximately from 60% in the first cycle up to 97% in the last cycle at flow back temperature and of 59.2% up to 96.9% at ambient temperature, it was not presented any significant effect which could be attributed to the temperature. During the exchange process, the cations present in the natural zeolite were exchanged with the ammonium ions, this process was not completed due to that retained ammonium quantity was major that of the desorpted ions, what shows that in addition of ion exchange, another type of sorption process exists. (Author)

Magnesium Borohydride: From Hydrogen Storage to Magnesium Battery**

OpenAIRE

Mohtadi, Rana; Matsui, Masaki; Arthur, Timothy S; Hwang, Son-Jong

2012-01-01

Beyond hydrogen storage: The first example of reversible magnesium deposition/stripping onto/from an inorganic salt was seen for a magnesium borohydride electrolyte. High coulombic efficiency of up to 94 % was achieved in dimethoxyethane solvent. This Mg(BH_4)_2 electrolyte was utilized in a rechargeable magnesium battery.

Protective layer formation on magnesium in cell culture medium.

Science.gov (United States)

Wagener, V; Virtanen, S

2016-06-01

In the past, different studies showed that hydroxyapatite (HA) or similar calcium phosphates can be precipitated on Mg during immersion in simulated body fluids. However, at the same time, in most cases a dark grey or black layer is built under the white HA crystals. This layer seems to consist as well of calcium phosphates. Until now, neither the morphology nor its influence on Mg corrosion have been investigated in detail. In this work commercially pure magnesium (cp) was immersed in cell culture medium for one, three and five days at room temperature and in the incubator (37 °C, 5% CO2). In addition, the influence of proteins on the formation of a corrosion layer was investigated by adding 20% of fetal calf serum (FCS) to the cell culture medium in the incubator. In order to analyze the formed layers, SEM images of cross sections, X-ray Photoelectron Spectroscopy (XPS), X-ray diffraction (XRD), Energy Dispersive X-ray Spectroscopy (EDX) and Fourier Transformed Infrared Spectroscopy (FTIR) measurements were carried out. Characterization of the corrosion behavior was achieved by electrochemical impedance spectroscopy (EIS) and by potentio-dynamic polarization in Dulbecco's Modified Eagle's Medium (DMEM) at 37°C. Surface analysis showed that all formed layers consist mainly of amorphous calcium phosphate compounds. For the immersion at room temperature the Ca/P ratio indicates the formation of HA, while in the incubator probably pre-stages to HA are formed. The different immersion conditions lead to a variation in layer thicknesses. However, electrochemical characterization shows that the layer thickness does not influence the corrosion resistance of magnesium. The main influencing factor for the corrosion behavior is the layer morphology. Thus, immersion at room temperature leads to the highest corrosion protection due to the formation of a compact outer layer. Layers formed in the incubator show much worse performances due to completely porous structures. The

Effects of soil phosphorus status on environmental risk assessment of glyphosate and glufosinate-ammonium.

Science.gov (United States)

Laitinen, Pirkko; Siimes, Katri; Rämö, Sari; Jauhiainen, Lauri; Eronen, Liisa; Oinonen, Seija; Hartikainen, Helinä

2008-01-01

The increased use of herbicides poses a risk to the aquatic environment. Easy and economical methods are needed to identify the fields where specific environment protection measures are needed. Phosphorus (P) and organophosphorus herbicides compete for the same adsorption sites in soil. In this study the relationship between P obtained in routine Finnish agronomic tests (acid ammonium acetate [P(AC)]) and adsorption of glyphosate and glufosinate-ammonium was investigated to determine whether P(AC) values could be used in the risk assessment. The adsorption of glyphosate ((N-(phosphonomethyl)glycine) and glufosinate-ammonium (2-amino-4-(hydroxymethylphosphinyl)butanoic acid) was studied in a clay and a sandy loam soil enriched with increasing amounts of P added as potassium dihydrogen phosphate. Desorption was also determined for some P-enriched soil samples. The adsorption of both herbicides diminished with increasing P(AC) value. The correlations between Freundlich adsorption coefficients obtained in the adsorption tests and P(AC) were nonlinear but significant (r > 0.98) in both soils. The exponential models of the relationship between soil P(AC) values and glyphosate adsorption were found to fit well to an independent Finnish soil data set (P glufosinate-ammonium). The desorption results showed that glufosinate-ammonium sorption is not inversely related to soil P status, and the high correlation coefficients obtained in the test of the model were thus artifacts caused by an abnormal concentration of exchangeable potassium in soil. The solved equations are a useful tool in assessing the leaching risks of glyphosate, but their use for glufosinate-ammonium is questionable.

Synthesis and characterization of ammonium phosphate fertilizers with boron

Directory of Open Access Journals (Sweden)

ANGELA MAGDA

2010-07-01

Full Text Available The concentration of boron, an essential micronutrient for plants, presents a narrow range between deficiency and toxicity. In order to provide the boron requirement for plants, and to avoid toxicity problems, boron compounds are mixed with basic fertilizers. Sodium borate pentahydrate was used as a boron source. Ammonium orthophosphates fertilizers with boron were prepared by neutralizing phosphoric acid with ammonia and addition of variable amounts of sodium tetraborate pentahydrate to the reaction mixture at a NH3:H3PO4 molar ratio of 1.5. The fertilizers obtained with boron contents ranging from 0.05 to 1 % (w/w were fully characterized by chemical analysis, thermal analysis, X-ray diffraction and infrared spectrophotometry. The studies showed that up to 500 °C, regardless of the boron content, no significant changes concerning thermal stability and nutritional properties occurred. Above 500 °C, an increase of thermal stability with an increase of the boron content was observed. X-Ray diffraction of a heat-treated sample containing 5 % (w/w boron indicated the appearance of boron orthophosphate, BPO4, as a new crystalline phase, and the disappearance of the previous structures above 500 °C, which explains the increase in thermal stability.

Treating ammonium-rich wastewater with sludge from water treatment plant to produce ammonium alum

Directory of Open Access Journals (Sweden)

Wen-Po Cheng

2016-03-01

Full Text Available This study applies a process to treat ammonium-rich wastewater using alum-generated sludge form water purification plant, and gain economic benefit by producing ammonium alum (Al(NH4(SO42·12H2O. The factors affecting production of ammonium alum include molar ratio of ammonium to aluminum concentration, sulfuric acid concentration, mixing speed, mixing time, standing time, and temperature. According to the equation for the ammonium removal reaction, the theoretical quantity of ammonium alum was calculated based on initial and final concentrations of ammonium. Then, the weight of ammonium alum crystal was divided by the theoretical weight to derive the recovery ratio. The optimum sludge and sulfuric acid dosage to treat about 17 g L−1 ammonium wastewater are 300 g L−1 and 100 mL L−1, respectively. The optimal dosage for wastewater is molar ratio of ammonium to aluminum of about 1 due to the aluminum dissolving in acidified wastewater. The ammonium removal efficiency is roughly 70% and the maximum recovery ratio for ammonium alum is 93% when the wastewater is mixed for 10 min at the mixing velocity gradient of 100 s−1. Ammonium alum production or ammonium removal can be enhanced by controlling the reaction at low temperatures.

The analysis of impurities in the diuranate-determination of phosphate by phosphomolybdate blue spectrophotometric method

International Nuclear Information System (INIS)

Sun Haobo

2014-01-01

Phosphomolybdenum blue spectrophotometric method was used for determination of phosphate in the diuranate. Diuranate was dissolved in nitric acid solution, in which formed a soluble heteropolyacid complex (namely phosphomolybdenum yellow) due to interaction of phosphate and ammonium molybdate. Then phosphomolybdenum yellow was reduced to phosphomolybdenum blue with Bismuth nitrate as catalyst. Colour intensity at 700 nm is in proportion to the content of phosphate determined by spectrophotometric method. This experiment presents good linearity at the range of 30 μg to 245 μg phosphate, and the relative standard deviation of the experimental result is 2.4%, and the recovery rate is from 95% to 105%. The determination result of phosphate content will not be effected under conditions of 4 mg of SiO 2 , 6 mg of Fe, 400 mg of Cl - and 4.5 mg of Ge in the solution. (author)

Phosphate Recovery from Human Waste via the Formation of Hydroxyapatite during Electrochemical Wastewater Treatment.

Science.gov (United States)

Cid, Clément A; Jasper, Justin T; Hoffmann, Michael R

2018-03-05

Electrolysis of toilet wastewater with TiO 2 -coated semiconductor anodes and stainless steel cathodes is a potentially viable onsite sanitation solution in parts of the world without infrastructure for centralized wastewater treatment. In addition to treating toilet wastewater, pilot-scale and bench-scale experiments demonstrated that electrolysis can remove phosphate by cathodic precipitation as hydroxyapatite at no additional energy cost. Phosphate removal could be predicted based on initial phosphate and calcium concentrations, and up to 80% total phosphate removal was achieved. While calcium was critical for phosphate removal, magnesium and bicarbonate had only minor impacts on phosphate removal rates at concentrations typical of toilet wastewater. Optimal conditions for phosphate removal were 3 to 4 h treatment at about 5 mA cm -2 (∼3.4 V), with greater than 20 m 2 m -3 electrode surface area to reactor volume ratios. Pilot-scale systems are currently operated under similar conditions, suggesting that phosphate removal can be viewed as an ancillary benefit of electrochemical wastewater treatment, adding utility to the process without requiring additional energy inputs. Further value may be provided by designing reactors to recover precipitated hydroxyapatite for use as a low solubility phosphorus-rich fertilizer.

Mg-phosphate ceramics produced from the product of thermal transformation of cement-asbestos

Czech Academy of Sciences Publication Activity Database

Pérez-Estébanez, Marta; Mácová, Petra; Šašek, Petr; Viani, Alberto; Gualtieri, A.

2014-01-01

Roč. 34, č. 2 (2014), s. 187-192 ISSN 1640-4920. [Conference on Environment and Mineral Processing /18./. Ostrava, 29.05.2014-31.05.2014] R&D Projects: GA MŠk(CZ) LO1219 Keywords : cement -asbestos * magnesium phosphate ceramics * amorphous Subject RIV: AL - Art, Architecture, Cultural Heritage http://www.potopk.com.pl/archiwum.html

Influence of ammonium nitrate on kinetics and mechanism of thermal decomposition of ammonium polyuranates

International Nuclear Information System (INIS)

Karelin, A.I.; Lobas, O.P.; Zhiganov, A.N.; Vasil'ev, K.F.; Zhiganova, A.A.

1988-01-01

The influence of ammonium nitrate on the mechanism and kinetics of dehydration and thermal decomposition of ammonium polyuranates was studied. An appreciable influence of the nitrate ion content in the samples of ammonium polyuranates on the development of thermal stability has been noted. The kinetic parameters of the thermal decomposition of ammonium polyuranates have been evaluated. A mechanism of the dehydration and thermal decomposition of ammonium polyuranates in the presence of ammonium nitrate has been proposed. It was shown that increase in the content of ammonium nitrate in the precipitate of ammonium polyuranates leads to a decrease in the specific surface of uranoso-uranic oxide

[A stable reagent for the-single stage determination of inorganic phosphate].

Science.gov (United States)

Pupyshev, A B

1991-01-01

A recipe of a simple reagent for phosphorus detection has been developed, consisting of ammonium molybdate (4 mM), sulfuric acid (0.2 N), and Tween-80 (0.2%). The developing phosphate staining may be registered in 15 min at a wavelength of 350 nm. The product molar extinction is equal to 1.20.10(4) M-1.cm-1, this being close to that of molybdic blue. Phosphate staining is characterized by the stability of results and insensitivity to the presence of a number of substances used in enzymology. The prepared reagent is fit for experiments within a fortnight if stored in the cold.

CO2 fixation using magnesium silicate minerals part 1: Process description and performance

International Nuclear Information System (INIS)

Fagerlund, Johan; Nduagu, Experience; Romão, Inês; Zevenhoven, Ron

2012-01-01

This paper describes a staged carbonation process for magnesium silicate mineral carbonation. This carbon dioxide capture and storage (CCS) alternative involves the production of magnesium hydroxide, followed by its carbonation in a pressurised fluidised bed (PFB) reactor. The goal is to utilise the heat of the carbonation reaction to drive the Mg(OH) 2 production step. The results show that Mg(OH) 2 can be produced successfully (up to 78% Mg extraction extent achieved so far) and efficiently from different serpentinite minerals from locations worldwide (Finland, Lithuania, Australia, Portugal…). From the extraction step, ammonium sulphate is recovered while iron oxides (from the mineral) are obtained as by-products. The carbonation step, while still being developed, resulted in >50%-wt conversion in 10 min (500 °C, 20 bar) for > 300 μm serpentinite-derived Mg(OH) 2 particles. Thus the reaction rate achieved so far is much faster than what is currently being considered fast in the field of mineral carbonation. -- Highlights: ► Magnesium silicate-based rock can sequester CO 2 as stable magnesium carbonate. ► Abundance of rock material offers a larger capacity than other CCS methods. ► Mg(OH) 2 production is followed by its carbonation in a pressurised fluidised bed. ► Carbonation reaches >50% in around 10 min for >0.3 mm particles. ► Mg(OH) 2 produced from different rock material show the same performance.

Influence of chloride ion concentration on the electrochemical corrosion behaviour of plasma electrolytic oxidation coated AM50 magnesium alloy

International Nuclear Information System (INIS)

Liang, J.; Srinivasan, P. Bala; Blawert, C.; Dietzel, W.

2010-01-01

The electrochemical degradation of a silicate- and a phosphate-based plasma electrolytic oxidation (PEO) coated AM50 magnesium alloy obtained using a pulsed DC power supply was investigated using potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) in NaCl solutions of different chloride ion concentrations viz., 0.01 M, 0.1 M, 0.5 M and 1 M. The surface of the PEO coated specimens after 50 h of immersion/EIS testing was examined by optical microscopy and scanning electron microscopy. The results showed that the corrosion deterioration of PEO coated magnesium alloy in NaCl solutions was significantly influenced by chloride ion concentration. The silicate-based coating was found to offer a superior corrosion resistance to the magnesium substrate than the phosphate-based coatings in lower chloride ion concentration NaCl solutions (0.01 M and 0.1 M NaCl). On the other hand both these PEO coatings were found to be highly susceptible to localized damage, and could not provide an effective corrosion protection to Mg alloy substrate in solutions containing higher chloride concentrations (0.5 M and 1 M). The extent of localized damage was observed to be more with increase in chloride concentration in both the cases.

Solubility of ammonium metavanadate in ammonium carbonate and sodium bicarbonate solutions at 25 deg C

International Nuclear Information System (INIS)

Fedorov, P.I.; Andreev, V.K.; Slotvinskij-Sidak, N.P.

1978-01-01

Solubility at 25 deg C has been studied in the system ammonium metavanadate - sodium bicarbonate - water which is a stable section of the corresponding quaternary mutual system. In the eutonic point the content of ammonium metavanadate is 4.95% and of sodium bicarbonate 12.1%. The crystallization branch of ammonium metavanadate has been studied in the system ammonium metavanadate - ammonium carbonate - water at 25 deg C. Metavanadate solubility attains minimum (0.14%) at ammonium carbonate concentration 2.6%. Three sections have been studied of the quaternary system ammonium - metavanadate - ammonium carbonate - sodium bicarbonate-water at 25 deg C in the crystallization region of ammonium metavanadate at a ratio of sodium bicarbonate to ammonium carbonate 3:1, 1:1, and 1:3. A region of minimum solubility of ammonium metavanadate has been detected (0.1%)

Elevated ammonium levels

DEFF Research Database (Denmark)

Søgaard, Rikke; Novak, Ivana; MacAulay, Nanna

2012-01-01

was not enhanced. The ammonium-induced stimulation of EAAT3 increased with increasing extracellular pH, suggesting that the gaseous form NH(3) mediates the effect. An ammonium-induced intracellular alkalinization was excluded as the cause of the enhanced EAAT3 activity because 1) ammonium acidified the oocyte...

Trehalose 6-phosphate phosphatases of Pseudomonas aeruginosa.

Science.gov (United States)

Cross, Megan; Biberacher, Sonja; Park, Suk-Youl; Rajan, Siji; Korhonen, Pasi; Gasser, Robin B; Kim, Jeong-Sun; Coster, Mark J; Hofmann, Andreas

2018-04-24

The opportunistic bacterium Pseudomonas aeruginosa has been recognized as an important pathogen of clinical relevance and is a leading cause of hospital-acquired infections. The presence of a glycolytic enzyme in Pseudomonas, which is known to be inhibited by trehalose 6-phosphate (T6P) in other organisms, suggests that these bacteria may be vulnerable to the detrimental effects of intracellular T6P accumulation. In the present study, we explored the structural and functional properties of trehalose 6-phosphate phosphatase (TPP) in P. aeruginosa in support of future target-based drug discovery. A survey of genomes revealed the existence of 2 TPP genes with either chromosomal or extrachromosomal location. Both TPPs were produced as recombinant proteins, and characterization of their enzymatic properties confirmed specific, magnesium-dependent catalytic hydrolysis of T6P. The 3-dimensional crystal structure of the chromosomal TPP revealed a protein dimer arising through β-sheet expansion of the individual monomers, which possess the overall fold of halo-acid dehydrogenases.-Cross, M., Biberacher, S., Park, S.-Y., Rajan, S., Korhonen, P., Gasser, R. B., Kim, J.-S., Coster, M. J., Hofmann, A. Trehalose 6-phosphate phosphatases of Pseudomonas aeruginosa.

Study on the relation between uranium content and total phosphorus in some sudanese phosphate ore samples

International Nuclear Information System (INIS)

Eltayeb, M. A. H.; Mohammed, A. A.

2003-01-01

In the present work uranium content and total phosphorus were determined in 30 phosphate ore samples collected from Kurun and Uro areas in Nuba Mountains in Sudan. Spectrophotometry technique was used for this purpose. Uranium analysis is based on the use of nitrogen (V) acid for leaching the rock, and treatment with ammonium carbonate solution, whereby uranium (Vi) is kept in solution as its carbonate complex. The ion exchange technique was used for the recovery of uranium. Uranium was eluted from the resin with 1 M hydrochloric acid. In the elute, uranium was determined spectrophotometrically by measurement of absorbance of the yellow uranium (Vi)-8-hydroxyquinolate complex at λ 400 nm. The total phosphorus was measured as (P 2 O 5 %) by treatment of the total liquor with ammonium molybdate solution. The absorbance of the blue complex was measured at λ 880 nm. The results show that a limited relation is existed between uranium content and total phosphorus in phosphate samples from kurun area, which contain 58.8 ppm uranium in average, where there are no relation is existed in phosphate samples from uro area, which contain 200 ppm uranium in average. (Author)

Study on the relation between uranium content and total phosphorus in some sudanese phosphate ore samples

International Nuclear Information System (INIS)

Mohammed, A.A.; Eltayeb, M.A.H.

2003-01-01

In the present work uranium content and total phosphorous were determined in 30 phosphate ore samples collected from Kurun and Uro areas in Nuba mountains in sudan. Spectrophotometry technique was used for this purpose. Uranium analysis is based on the use of nitrogen (V) acid for leaching the rock, and treatment with ammonium carbonate solution, whereby uranium (VI) is kept in solution as its carbonate complex. The ion-exchange technique was used for the recovery of uranium. Uranium was eluted from the resin with 1 M hydrochloric acid. In the elute, uranium was determined spectrophotometrically by measurement of the absorbance of the yellow uranium (VI) - 8- hydroxyquinolate complex at λ 400 nm. The total phosphorus was measured as (P 2 O 5 %) by treatment of the leach liquor with ammonium molybdate solution. The absorbance of the blue complex was measured at λ 880 nm. The results show that a limited relation is existed between uranium content and total phosphorus in phosphate samples from Kurun area, which contain 58.8 ppm uranium in average, where there are no relation is existed in phosphate samples samples from Uro area, which contain 200 ppm uranium in average

Magnesium Attenuates Phosphate-Induced Deregulation of a MicroRNA Signature and Prevents Modulation of Smad1 and Osterix during the Course of Vascular Calcification

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Loïc Louvet

2016-01-01

Full Text Available Vascular calcification (VC is prevalent in patients suffering from chronic kidney disease (CKD. High phosphate levels promote VC by inducing abnormalities in mineral and bone metabolism. Previously, we demonstrated that magnesium (Mg2+ prevents inorganic phosphate- (Pi- induced VC in human aortic vascular smooth muscle cells (HAVSMC. As microRNAs (miR modulate gene expression, we investigated the role of miR-29b, -30b, -125b, -133a, -143, and -204 in the protective effect of Mg2+ on VC. HAVSMC were cultured in the presence of 3 mM Pi with or without 2 mM Mg2+ chloride. Total RNA was extracted after 4 h, 24 h, day 3, day 7, and day 10. miR-30b, -133a, and -143 were downregulated during the time course of Pi-induced VC, whereas the addition of Mg2+ restored (miR-30b or improved (miR-133a, miR-143 their expression. The expression of specific targets Smad1 and Osterix was significantly increased in the presence of Pi and restored by coincubation with Mg2+. As miR-30b, miR-133a, and miR-143 are negatively regulated by Pi and restored by Mg2+ with a congruent modulation of their known targets Runx2, Smad1, and Osterix, our results provide a potential mechanistic explanation of the observed upregulation of these master switches of osteogenesis during the course of VC.

Magnesium borohydride: from hydrogen storage to magnesium battery.

Science.gov (United States)

Mohtadi, Rana; Matsui, Masaki; Arthur, Timothy S; Hwang, Son-Jong

2012-09-24

Beyond hydrogen storage: The first example of reversible magnesium deposition/stripping onto/from an inorganic salt was seen for a magnesium borohydride electrolyte. High coulombic efficiency of up to 94 % was achieved in dimethoxyethane solvent. This Mg(BH(4))(2) electrolyte was utilized in a rechargeable magnesium battery. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Investigation of ammonium nitrate effect on kinetics and mechanism of thermal decomposition of ammonium polyuranates

International Nuclear Information System (INIS)

Karelin, A.I.; Lobas, O.P.; Zhiganov, A.N.; Vasil'ev, K.F.; Zhiganova, A.A.

1987-01-01

A study was made on ammonium nitrate effect on the mechanism and kinetics of dehydration and thermal decomposition of ammonium polyuranates. Sufficient effect of nitrate ion content in ammonium polyuranate samples on their thermal stability was noted. Kinetic parameters of thermal decomposition of ammonium polyuranates were evaluated. Mechanism of dehydration and thermal decomposition of ammonium polyuranates in the presence of ammonium nitrate was suggested. It was shown that increase of ammonium nitrate content in ammonium polyuranate precipitate resulted to reduction of the specific surface of prepared uranium mixed oxide

A radiochemical method for carbamoyl-phosphate synthetase I: application to rats fed a hyperproteic diet

OpenAIRE

Arriarán, Sofía; Agnelli, Silvia; Fernández López, José Antonio; Remesar Betlloch, Xavier; Alemany, Marià, 1946-

2012-01-01

A method for the measurement of carbamoyl-phosphate synthetase I activity in animal tissues has been developed using the livers of rats under normal and hyperproteic diets. The method is based on the incorporation of 14C-ammonium bicarbonate to carbamoyl-phosphate in the presence of ATP-Mg and N-acetyl-glutamate. The reaction is stopped by chilling, lowering the pH and adding ethanol. Excess bicarbonate is flushed out under a gentle stream of cold CO2. The only label remaining in the medium w...

Microbial Leaching of Some Valuable Elements From Egyptian Phosphate Rock

International Nuclear Information System (INIS)

Kamal, H.M.; Hassanein, R.A.; Mahdy, H.M.A.; Mahmoud, K.F.; Abouzeid, M.A.

2012-01-01

Four phosphate rock samples representing different phosphate mineralization modes in Egypt were selected from Abu Tartar, Nile valley and Red sea areas. Factors affecting the phosphate rock solubilization and some of the contained valuable elements by Aspergillus niger, Penicillium sp. and Pseudomonas fluorescence, were studied with especial orientation towards the completion of phosphate rock samples solubilization especially die low grade one. Effect of nitrogen source type on leaching efficiency by Aspergillus niger when two nitrogen sources on the phosphate bioleaching efficiency, it is clear that the ammonium chloride is more favorable as nitrogen source than sodium nitrate in the bioleaching of phosphate rocks. When Aspergillus niger was applied under die following conditions: 50 g/1 of sucrose as a carbon source, 0.1 N of ammonium chloride as a nitrogen source, 10 days incubation period, 0.5% solid: liquid ratio for P 2 O 5 and 5% for U and REE and - 270 mesh of grain size. The optimum leaching of P 2 O 5 , U and REE from phosphate rock samples reached (23.27%, 17.4%, 11.4%, respectively), while at -60 mesh they reached to 16.58%, 28.9%, 30.2% respectively. The optimum conditions for the maximal leaching efficiencies of P 2 O 5 , U and REE when applying the Penicillium sp. from the phosphate rock samples were: 100 g/1 of sucrose as a carbon source for P 2 O 5 and U and 10 g/1 for REE, 7,15 and 10 days incubation period for P 2 O 5 , U and REE, respectively, 0.5% solid: liquid ratio for P 2 O 5 and 5% for U and REE. Finally, the application of phosphate rock samples grinded to -270 mesh of grain size for P 2 O 5 and (-60 to -140) for U and REE. The studied leaching efficiency of P 2 O 5 , U and REE gave at -270 mesh 33.66%, 24.3%, 15.9% respectively, while at -60 mesh they gave 33.76%, 26.7%, 17.8% and at -140 mesh gave 31.32%, 27.9%, 17.6%, respectively.The optimum conditions for the P 2 O 5 leaching efficiency when applying the Pseudomonas fluorescence were

Influence of the Composition of the Hank’s Balanced Salt Solution on the Corrosion Behavior of AZ31 and AZ61 Magnesium Alloys

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Jakub Tkacz

2017-11-01

Full Text Available The electrochemical corrosion characteristics of AZ31 and AZ61 magnesium alloys were analyzed in terms of potentiodynamic tests and electrochemical impedance spectroscopy. The influence of the solution composition and material surface finish was examined also through the analysis of corrosion products created on the samples’ surface after electrochemical measurements in terms of scanning electron microscopy using energy-dispersive spectroscopy. Obtained data revealed the differences in the response of the magnesium alloys to enriched Hank’s Balanced Salt Solution—HBSS+ (with Mg2+ and Ca2+ ions and Hank’s Balanced Salt Solution—HBSS (without Mg2+ and Ca2+ ions. Both examined alloys exhibited better corrosion resistance from the thermodynamic and kinetic point of view in the enriched HBSS+. AZ61 magnesium alloy reached higher values of polarization resistance than AZ31 magnesium alloy in both the used corrosion solutions. Phosphate-based corrosion products were characteristic for the AZ31 and AZ61 alloys tested in the HBSS (without Mg2+ and Ca2+ ions. The combination of phosphate-based corrosion products and clusters of MgO and Mg(OH2 was typical for the surface of samples tested in the enriched HBSS+ (with Mg2+ and Ca2+ ions. Pitting corrosion attack was observed only in the case of enriched HBSS+.

Novel magnesium alloy Mg–2La caused no cytotoxic effects on cells in physiological conditions

Energy Technology Data Exchange (ETDEWEB)

Weizbauer, Andreas, E-mail: weizbauer.andreas@mh-hannover.de [Laboratory for Biomechanics and Biomaterials, Department of Orthopedic Surgery, Hannover Medical School, Anna-von-Borries-Straße 1-7, 30625 Hannover (Germany); CrossBIT, Center for Biocompatibility and Implant-Immunology, Department of Orthopedic Surgery, Hannover Medical School, Feodor-Lynen-Str. 31, 30625 Hannover (Germany); Seitz, Jan-Marten [Institute of Materials Science, Leibniz Universität Hannover, An der Universität 2, 30823 Garbsen (Germany); Werle, Peter [ABB AG, Trafoweg 4, 06112 Halle (Germany); Hegermann, Jan [Institute of Functional and Applied Anatomy, Hannover Medical School, Carl-Neuberg-Straße 1, 30625 Hannover (Germany); Willbold, Elmar [Laboratory for Biomechanics and Biomaterials, Department of Orthopedic Surgery, Hannover Medical School, Anna-von-Borries-Straße 1-7, 30625 Hannover (Germany); CrossBIT, Center for Biocompatibility and Implant-Immunology, Department of Orthopedic Surgery, Hannover Medical School, Feodor-Lynen-Str. 31, 30625 Hannover (Germany); Eifler, Rainer [Institute of Materials Science, Leibniz Universität Hannover, An der Universität 2, 30823 Garbsen (Germany); Windhagen, Henning [Laboratory for Biomechanics and Biomaterials, Department of Orthopedic Surgery, Hannover Medical School, Anna-von-Borries-Straße 1-7, 30625 Hannover (Germany); Reifenrath, Janin [Small Animal Clinic, University of Veterinary Medicine Hannover, Bünteweg 9, 30559 Hannover (Germany); Waizy, Hazibullah [Laboratory for Biomechanics and Biomaterials, Department of Orthopedic Surgery, Hannover Medical School, Anna-von-Borries-Straße 1-7, 30625 Hannover (Germany)

2014-08-01

Using several different in vitro assays, a new biodegradable magnesium alloy Mg–2La, composed of 98% magnesium and 2% lanthanum, was investigated as a possible implant material for biomedical applications. An in vitro cytotoxicity test, according to EN ISO 10993-5/12, with L929 and human osteoblastic cells identified no toxic effects on cell viability at physiological concentrations (at 50% dilutions and higher). The metabolic activity of human osteoblasts in the 100% extract was decreased to < 70% and was therefore rated as cytotoxic. The degradation rates of Mg–2La were evaluated in phosphate buffered saline and four different cell culture media. The degradation rates were shown to be influenced by the composition of the solution, and the addition of fetal bovine serum slightly accelerated the corrosive process. The results of these in vitro experiments suggest that Mg–2La is a promising candidate for use as an orthopedic implant material. - Highlights: • A new magnesium alloy (Mg–2La) has been developed. • Magnesium alloy Mg–2La revealed no toxic effect in physiological concentrations. • Degradation rates were influenced by the corrosion media. • The addition of fetal bovine serum increased the corrosive process slightly.

Novel magnesium alloy Mg–2La caused no cytotoxic effects on cells in physiological conditions

International Nuclear Information System (INIS)

Weizbauer, Andreas; Seitz, Jan-Marten; Werle, Peter; Hegermann, Jan; Willbold, Elmar; Eifler, Rainer; Windhagen, Henning; Reifenrath, Janin; Waizy, Hazibullah

2014-01-01

Using several different in vitro assays, a new biodegradable magnesium alloy Mg–2La, composed of 98% magnesium and 2% lanthanum, was investigated as a possible implant material for biomedical applications. An in vitro cytotoxicity test, according to EN ISO 10993-5/12, with L929 and human osteoblastic cells identified no toxic effects on cell viability at physiological concentrations (at 50% dilutions and higher). The metabolic activity of human osteoblasts in the 100% extract was decreased to < 70% and was therefore rated as cytotoxic. The degradation rates of Mg–2La were evaluated in phosphate buffered saline and four different cell culture media. The degradation rates were shown to be influenced by the composition of the solution, and the addition of fetal bovine serum slightly accelerated the corrosive process. The results of these in vitro experiments suggest that Mg–2La is a promising candidate for use as an orthopedic implant material. - Highlights: • A new magnesium alloy (Mg–2La) has been developed. • Magnesium alloy Mg–2La revealed no toxic effect in physiological concentrations. • Degradation rates were influenced by the corrosion media. • The addition of fetal bovine serum increased the corrosive process slightly

Self-propelled magnesium based micromotors: synthesis and magnetic steering

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Jin Dongdong

2015-01-01

Full Text Available In this work the magnesium based Janus micromotors were prepared by an asymmetric coating of Co-Au bilayer on the surface of Mg microparticles. The micromotor could efficiently self-propel in phosphate buffer saline (PBS with a highest speed of 221 μm·s−1 without any extra additives through the macrogalvanic corrosion and pitting corrosion mechanism. The influence of pH value of PBS buffer on the motion of micromotor was also investigated. Moreover, we demonstrated that the motion of micromotor could be controlled by an external magnetic field rapidly and accurately, indicating the potential application in biomedicine.

Magnesium in pregnancy.

Science.gov (United States)

Dalton, Lynne M; Ní Fhloinn, Deirdre M; Gaydadzhieva, Gergana T; Mazurkiewicz, Ola M; Leeson, Heather; Wright, Ciara P

2016-09-01

Magnesium deficiency is prevalent in women of childbearing age in both developing and developed countries. The need for magnesium increases during pregnancy, and the majority of pregnant women likely do not meet this increased need. Magnesium deficiency or insufficiency during pregnancy may pose a health risk for both the mother and the newborn, with implications that may extend into adulthood of the offspring. The measurement of serum magnesium is the most widely used method for determining magnesium levels, but it has significant limitations that have both hindered the assessment of deficiency and affected the reliability of studies in pregnant women. Thus far, limited studies have suggested links between magnesium inadequacy and certain conditions in pregnancy associated with high mortality and morbidity, such as gestational diabetes, preterm labor, preeclampsia, and small for gestational age or intrauterine growth restriction. This review provides recommendations for further study and improved testing using measurement of red cell magnesium. Pregnant women should be counseled to increase their intake of magnesium-rich foods such as nuts, seeds, beans, and leafy greens and/or to supplement with magnesium at a safe level. © The Author(s) 2016. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Ammonium nitrate explosion hazards

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Negovanović Milanka

2015-01-01

Full Text Available Ammonium nitrate (AN primarily is used as a fertilizer but it is also very important compound in the production of industrial explosives. The application of ammonium nitrate in the production of industrial explosives was related with the early era of Nobel dynamite and widely increased with the appearance of blasting agents such as ANFO and Slurry, in the middle of the last Century. Throughout the world millions of tons of ammonium nitrate are produced annually and handled without incident. Although ammonium nitrate generally is used safely, accidental explosions involving AN have high impact resulting in loss of lives and destruction of property. The paper presents the basic properties of ammonium nitrate as well as hazards in handling of ammonium nitrate in order to prevent accidents. Several accidents with explosions of ammonium nitrate resulted in catastrophic consequences are listed in the paper as examples of non-compliance with prescribed procedures.

Radiochemical studies on amorphous zirconium phosphate

Energy Technology Data Exchange (ETDEWEB)

Dyer, A; Moores, G E [Salford Univ. (UK). Dept. of Chemistry and Applied Chemistry

1981-01-01

Amorphous zirconium phosphate (ZrP) is used in some hemodialysis machines for the regeneration of dialysate. Its function is to adsorb ammonium ions formed by the pretreatment of urea by urease. It also adsorbs Ca, Mg and K ions but leaches phosphate ions which are then removed (along with F/sup -/ ions) by a bed of hydrous zirconium oxide. The sodium form of ZrP is used although other forms have been suggested for use. The work reported here describes some preliminary radiochemical studies on the mechanism of release of phosphate ions and its possible relationship to sodium ion-exchange. /sup 32/P labelled material (HHZrP) was used for elution experiments with deionized water and buffer solutions having the pH's 4.2, 7.0 and 9.2. Buffer solutions used were as supplied by BDH. Elution was at four different temperatures in the range 293 to 363/sup 0/C. In the second series of experiments HHZrP was suspended in a NaCl solution labelled with /sup 22/Na. From this, /sup 22/Na labelled ZrP (NaHZrP) was prepared and eluted in the same way as the HHZrP. Results are given and discussed.

Magnesium stannide as a high-capacity anode for magnesium-ion batteries

Science.gov (United States)

Nguyen, Dan-Thien; Song, Seung-Wan

2017-11-01

Driven by the limited global resources of lithium, magnesium metal batteries are considered as potential energy storage systems. The battery chemistry of magnesium metal anode, however, limits the selection of electrolytes, cathode materials and working temperature, making the realization of magnesium metal batteries complicated. Herein, we report the development of a new magnesium-insertion anode, magnesium stannide (Mg2Sn), and demonstrate reversible electrochemical Mg2+-extraction and insertion of Mg2Sn anode at 0.2 V versus Mg, delivering discharge capacity of 270 mAhg-1 in a half-cell with the electrolyte of PhMgCl/THF and enabling of room temperature magnesium-ion batteries with Mg2Sn anode combined with Mg-free oxide cathode and conventional-type electrolyte of Mg(TFSI)2/diglyme. The combination of Mg2Sn anode with various cathodes and electrolytes holds great promise for enabling room temperature magnesium-ion batteries.

Use of ASP for Removal of Fluorine and Ammonium Ions

International Nuclear Information System (INIS)

Martin HB, A; Las, T

1998-01-01

The purified zeolites from Bayah, Lampung dan Tasik have been modified into microporous alumino-silico phosphate (ASP) which could be used as anion and cation exchangers. ASP has been prepared by mixing purified zeolites and ammonium dihydrogen phosphate in weight ratios of 1 :1, 1 :5 and 5:1. The materials have been characterized by XRF, XRD and TG. The ion-exchange experiments have been performed by batch method for various concentrations of 0.01, 0.04, 0.08, 0.2 and O,4 NF and NH 4 ion. Column experiment has been performed for: 500 ppm of ion F ( 0,026 N) and 100 ppm (0.0055 N) of ion NH 4 concentrations respectively, fed into 1 cm diameter column containing 3 g pure ion exchangers. From batch experiment the fluorine sorption increases following the increase the concentration and F could be adsorbed up to about 1.09 -9.17 eq/kg for in the range of concentration 0.01 - 0.08 N. For higher fluorine concentration, the fluorine sorption tends to fluctuate. The ammonium sorption experiments obtain similar results for purified zeolites and ASP. The ion could be absorbed up to about 1.09 - 14.24 eq/kg. In column experiment, 1 g ASP could absorb fluorine up to about 278,48 - 334,19 BV ( 900-1300 ml) at 50% BT, and absorb NH 4 about 219.64 - 297.17 BV (850 -1150 ml) separately. These result shows that the ASP might be a potential material to be used for removal of ion F and NH 4 from the waste generayed in the fuel element fabrication

Effect of magnesium deficiency on renal magnesium and calcium transport in the rat.

OpenAIRE

Carney, S L; Wong, N L; Quamme, G A; Dirks, J H

1980-01-01

Recollection of micropuncture experiments were performed on acutely thyroparathyroidectomized rats rendered magnesium deficient by dietary deprivation. Urinary magnesium excretion fell from a control of 15 to 3% of the filtered load after magnesium restriction. The loop of Henle, presumably the thick ascending limb, was the major modulator for renal magnesium homeostasis. The transport capacity for magnesium, however, was less in deficient rats than control animals. Absolute magnesium reabsor...

Magnesium, magnesium alloys, and magnesium composites

National Research Council Canada - National Science Library

Gupta, M; Sharon, Nai Mui Ling

2011-01-01

.... With the popularity of magnesium-based materials in the automotive, aerospace, electronics, and sports equipment industries, and its unique role as a lightweight, energy-saving and high-performance...

Crystallization characteristics of ammonium uranyl carbonate (AUC) in ammonium carbonate solutions

International Nuclear Information System (INIS)

Kim, T.J.; Jeong, K.C.; Park, J.H.; Chang, I.S.; Choi, C.S.

1994-01-01

Ammonium carbonate solutions with an excessive amount of NH 3 were produced in a commercial AUC (ammonium uranyl carbonate) conversion plant. In this study the AUC crystals, precipitated with uranyl nitrate and ammonium carbonate solutions prepared in the laboratory, were characterized to determine the feasibility of recycling ammonium carbonate solution. The AUC crystals were easily agglomerated with the increasing concentration of CO 3 2- and mole ratio of NH 4 + /CO 3 2- in ammonium carbonate solution. Effects of a mixing system for the solution in the AUC crystallizer and the feed location of the solution onthe agglomeration of AUC crystals were also studied along with the effects of agglomerated AUC powders on UO 2 powders. Finally, the feasibility of manufacturing UO 2 fuel with a sintered pellet density of 10.52 g/cm 3 , using the AUC powders generated in this experiment, was demonstrated. (orig.)

Reaction of ammonium triphosphate with gadolinium nitrate in aqueous solution at 273K

International Nuclear Information System (INIS)

Rodicheva, G.V.; Tananaev, I.V.; Romanova, N.M.

1982-01-01

The solubility in the system (NW 4 ) 5 P 3 O 10 -Gd(NO 3 ) 3 - H 2 O (273 K) is studied. Depending on the reagent ratio formation of the compounds Gd 5 (P 3 O 10 ) 3 x22H 2 O, NH 4 Gd 3 (P 3 O 10 ) 2 x12H 2 O and (NH 4 ) 3 Gd 4 (P 3 O 10 ) 3 x14H 2 O is established. Gadolinium triphosphates, separated from solution, are studied using the methods of paper chromatography, X-ray diffractometry, thermography. Simultaneously with thermal dehydration of gadolinium triphosphates the processes of triphosphate decomposition and phosphate anion condensation take place. A mixture of crystalline ortho-phosphate and long- chain polyphosphate of gadolinium is the final product of thermal decomposition (1063 K) of normal and doubl e ammonium- containing gadolinium triphosphates [ru

Solid Phases Precipitating in Artificial Urine in the Absence and Presence of Bacteria Proteus mirabilis—A Contribution to the Understanding of Infectious Urinary Stone Formation

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Jolanta Prywer

2018-04-01

Full Text Available Magnesium ammonium phosphate hexahydrate, called struvite, is the dominant component of infectious urinary stones. In addition to struvite, infectious urinary stones include solid phases with poor crystallinity as well as amorphous matter. This article is devoted to the analysis of these solid phases, because they have not been characterized well until now. The solid phases tested were obtained from artificial urine in the absence and presence of Proteus mirabilis. The solid phases were characterized by different techniques (X-ray Diffraction, Energy Dispersive X-ray, Scanning Electron Microscopy, as well as Raman and Infrared Spectroscopies. According to the results these phases are carbonate apatite (CA, hydroxylapatite (HAP, amorphous calcium carbonate (ACC, amorphous calcium phosphate (ACP and/or amorphous carbonated calcium phosphate (ACCP. Carbonate apatite and hydroxylapatite may occur in non-stoichiometric forms, i.e., various anions can be substituted for CO32−, OH−, and PO43− groups in them. The non-stoichiometry of carbonate apatite and hydroxylapatite also implies a deficiency of calcium ions, i.e., calcium ions may be partially replaced by other cations. Experimental techniques and chemical speciation analysis demonstrate that the presence of magnesium influences the formation of CA and HAP.

Increased water hardness and magnesium levels may increase occurrence of urolithiasis in cows from the Burdur region (Turkey).

Science.gov (United States)

Sahinduran, S; Buyukoglu, T; Gulay, M S; Tasci, F

2007-08-01

Objectives of the study were to measure water hardness in Burdur, and to establish its possible association with urolithiasis in cattle. Water samples were obtained from different stables (n = 15). Water hardness and the concentrations of potassium, calcium, magnesium, sodium, iron, zinc, manganese and copper ions were calculated from these water samples. Total hardness of the samples (mean 285 ppm) exceeded the standards and the water was characterized by high content of magnesium ions. Kidneys (n = 500) were collected randomly from slaughterhouses and examined for urolithiasis. Urolithiasis was observed in 102 kidneys (20.4%). The weights of the stones were between 0.02 and 237.44 g and the colour varied from white to brown. The calculi collected had various shapes and composed of calcium apatite (42.45%), struvite (20.15%), magnesium carbonate (15.15%), calcium carbonate (12.12%), and calcium phosphate cystine (10.13%). It was concluded that high water hardness with high magnesium ion concentrations in water may contribute to urolithiasis and needs to be investigated further in future studies.

Myth or Reality-Transdermal Magnesium?

Science.gov (United States)

Gröber, Uwe; Werner, Tanja; Vormann, Jürgen; Kisters, Klaus

2017-07-28

In the following review, we evaluated the current literature and evidence-based data on transdermal magnesium application and show that the propagation of transdermal magnesium is scientifically unsupported. The importance of magnesium and the positive effects of magnesium supplementation are extensively documented in magnesium deficiency, e.g., cardiovascular disease and diabetes mellitus. The effectiveness of oral magnesium supplementation for the treatment of magnesium deficiency has been studied in detail. However, the proven and well-documented oral magnesium supplementation has become questioned in the recent years through intensive marketing for its transdermal application (e.g., magnesium-containing sprays, magnesium flakes, and magnesium salt baths). In both, specialist and lay press as well as on the internet, there are increasing numbers of articles claiming the effectiveness and superiority of transdermal magnesium over an oral application. It is claimed that the transdermal absorption of magnesium in comparison to oral application is more effective due to better absorption and fewer side effects as it bypasses the gastrointestinal tract.

Magnesium stearine production via direct reaction of palm stearine and magnesium hydroxide

Science.gov (United States)

Pratiwi, M.; Ylitervo, P.; Pettersson, A.; Prakoso, T.; Soerawidjaja, T. H.

2017-06-01

The fossil oil production could not compensate with the increase of its consumption, because of this reason the renewable alternative energy source is needed to meet this requirement of this fuel. One of the methods to produce hydrocarbon is by decarboxylation of fatty acids. Vegetable oil and fats are the greatest source of fatty acids, so these can be used as raw material for biohydrocarbon production. From other researchers on their past researchs, by heating base soap from divalent metal, those metal salts will decarboxylate and produce hydrocarbon. This study investigate the process and characterization of magnesium soaps from palm stearine by Blachford method. The metal soaps are synthesized by direct reaction of palm stearine and magnesium hydroxide to produce magnesium stearine and magnesium stearine base soaps at 140-180°C and 6-10 bar for 3-6 hours. The operation process which succeed to gain metal soaps is 180°C, 10 bar, for 3-6 hours. These metal soaps are then compared with commercial magnesium stearate. Based on Thermogravimetry Analysis (TGA) results, the decomposition temperature of all the metal soaps were 250°C. Scanning Electron Microscope with Energy Dispersive X-ray (SEM-EDX) analysis have shown the traces of sodium sulphate for magnesium stearate commercial and magnesium hydroxide for both type of magnesium stearine soaps. The analysis results from Microwave Plasma-Atomic Emission Spectrometry (MP-AES) have shown that the magnesium content of magnesium stearine approximate with magnesium stearate commercial and lower compare with magnesium stearine base soaps. These experiments suggest that the presented saponification process method could produced metal soaps comparable with the commercial metal soaps.

Low magnesium level

Science.gov (United States)

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, ...

System and process for production of magnesium metal and magnesium hydride from magnesium-containing salts and brines

Science.gov (United States)

McGrail, Peter B.; Nune, Satish K.; Motkuri, Radha K.; Glezakou, Vassiliki-Alexandra; Koech, Phillip K.; Adint, Tyler T.; Fifield, Leonard S.; Fernandez, Carlos A.; Liu, Jian

2016-11-22

A system and process are disclosed for production of consolidated magnesium metal products and alloys with selected densities from magnesium-containing salts and feedstocks. The system and process employ a dialkyl magnesium compound that decomposes to produce the Mg metal product. Energy requirements and production costs are lower than for conventional processing.

Anticorrosive magnesium hydroxide coating on AZ31 magnesium alloy by hydrothermal method

International Nuclear Information System (INIS)

Zhu Yanying; Wu Guangming; Xing Guangjian; Li Donglin; Zhao Qing; Zhang Yunhong

2009-01-01

Magnesium alloys are potential biodegradable biomaterials in orthopedic surgery. However, the rapid degradation rate has limited their application in biomedical field. A great deal of studies have been done to improve the resistance of magnesium alloys. In this article, An anticorrosive magnesium hydroxide coating with a thickness of approximately 100μm was formed on an AZ31 magnesium alloy by hydrothermal method. The morphology of the coatings were observed by an optical microscope and SEM. And the samples were soaked in hank's solution (37 deg. C) to investigate the corrosion resistance. Magnesium alloy AZ31 with magnesium hydroxide coatings present superior corrosion resistance than untreated samples.

Magnesium and Space Flight

Science.gov (United States)

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

Magnesium and Space Flight

Directory of Open Access Journals (Sweden)

Scott M. Smith

2015-12-01

Full Text Available 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.

In vitro studies on magnesium uptake by rumen epithelium using magnesium-28

International Nuclear Information System (INIS)

Martens, H.; Harmeyer, J.; Breves, G.

1976-01-01

Magnesium-28 transfer across the rumen epithelium has been studied using surviving epithelia in an in vitro system. Net absorption of magnesium in the direction from lumen to blood could be observed as the result of two opposite unidirectional fluxes of different magnitude. Net uptake of magnesium occurred against an electrical potential difference, and was associated with the presence of an unaltered transmural potential difference in the mucosal tissue. Both the net transfer of magnesium and the transmural potential difference decreased during two hours of incubation. Unidirectional fluxes of magnesium and net efflux from the lumen were markedly reduced although not completely inhibited by the addition of ouabain (10 -4 mol/l). The findings suggest that the mechanism of magnesium absorption by the rumen epithelium can be considered as an active transport process, and that the rumen is the main area of magnesium absorption in the living animal. (author)

Phosphates nanoparticles doped with zinc and manganese for sunscreens

Energy Technology Data Exchange (ETDEWEB)

Araujo, T.S. de, E-mail: tatiana.araujo@ifs.edu.br [Departamento de Fisica, Universidade Federal de Sergipe, Sergipe (Brazil); Instituto Federal de Ciencias e Tecnologia de Sergipe, Sergipe (Brazil); Souza, S.O. de [Departamento de Fisica, Universidade Federal de Sergipe, Sergipe (Brazil); Miyakawa, W. [Divisao de Fotonica - Instituto de Estudos Avancados, Sao Jose dos Campos (Brazil); Sousa, E.M.B. de [Centro de Desenvolvimento de Tecnologia Nuclear - CDTN/CNEN, Minas Gerais (Brazil)

2010-12-01

The crescent number of skin cancer worldwide gives impulse to the development of sunscreen that can both prevent skin cancer and also permit gradual tanning. In this work, the synthesis of hydroxyapatite and tricalcium phosphate nanocrystalline powders was investigated in order to obtain materials with optical properties and appropriate size for sunscreen. Pure, Zn{sup 2+}-doped and Mn{sup 2+}-doped hydroxyapatite (HAP) and tricalcium phosphate ({beta}-TCP) were produced by the wet precipitation process using diammonium phosphate, calcium nitrate, ammonium hydroxide, zinc nitrate and manganese nitrate as reagents. The pure and doped HAP precipitates were calcined at 500 deg. C for 1 h, while the {beta}-TCP (pure and doped) were calcined at 800 deg. C for 2 h. The powder samples were characterized by X-ray diffraction (XRD), energy dispersive X-ray fluorescence (EDX), atomic force microscopy (AFM) and ultraviolet (UV)-vis spectroscopy. XRD and EDX showed the formation of the expected materials (HAP and {beta}-TCP) without toxic components. AFM micrographs showed aggregated ellipsoidal particles with dimensions smaller than 120 nm. Optical absorption spectra showed that the calcium phosphate produced in this work absorbs in the UV region. The obtained materials presented structural, morphological and optical properties that allow their use as the active centers in sunscreens.

Phosphates nanoparticles doped with zinc and manganese for sunscreens

International Nuclear Information System (INIS)

Araujo, T.S. de; Souza, S.O. de; Miyakawa, W.; Sousa, E.M.B. de

2010-01-01

The crescent number of skin cancer worldwide gives impulse to the development of sunscreen that can both prevent skin cancer and also permit gradual tanning. In this work, the synthesis of hydroxyapatite and tricalcium phosphate nanocrystalline powders was investigated in order to obtain materials with optical properties and appropriate size for sunscreen. Pure, Zn 2+ -doped and Mn 2+ -doped hydroxyapatite (HAP) and tricalcium phosphate (β-TCP) were produced by the wet precipitation process using diammonium phosphate, calcium nitrate, ammonium hydroxide, zinc nitrate and manganese nitrate as reagents. The pure and doped HAP precipitates were calcined at 500 deg. C for 1 h, while the β-TCP (pure and doped) were calcined at 800 deg. C for 2 h. The powder samples were characterized by X-ray diffraction (XRD), energy dispersive X-ray fluorescence (EDX), atomic force microscopy (AFM) and ultraviolet (UV)-vis spectroscopy. XRD and EDX showed the formation of the expected materials (HAP and β-TCP) without toxic components. AFM micrographs showed aggregated ellipsoidal particles with dimensions smaller than 120 nm. Optical absorption spectra showed that the calcium phosphate produced in this work absorbs in the UV region. The obtained materials presented structural, morphological and optical properties that allow their use as the active centers in sunscreens.

Magnesium, magnesium alloys, and magnesium composites

National Research Council Canada - National Science Library

Gupta, M; Sharon, Nai Mui Ling

2011-01-01

... of science, characteristics, and applications. It emphasizes the properties of magnesium-based composites and the effects of different types of reinforcements, from micron length to nanometer scale, on the properties of the resulting composites...

Ammonium vanadate titrimetric method for determination of micro amount uranium in rock and soil by using vanadate-gold indicator

International Nuclear Information System (INIS)

Li Yucheng.

1990-01-01

A new vanadate-gold indicator was successfully applied to the ammonium vanadate titrimetric method for determination of micro amount uranium in rock and soil. Uranium in 0.1g of sample is reduced by titanium trichloride in phosphoric acid. Excessive Ti (III) and other low-valent ions are oxidized by sodium nitrite, while the complex of uranium (IV)-phosphate is not oxidized. Excessive nitrite is destroyed by urea. When the concentration of phosphoric acid is 22-24 % , adding two drops of vanadate-gold indicator, uranium (IV) is titrated by standardized ammonium vanadate solution (T = 0.02-20gU/ml) and the end-point is judged by a violet-red color appearance

Crystallisation of mixtures of ammonium nitrate, ammonium sulphate and soot

NARCIS (Netherlands)

Dougle, P.G.; Veefkind, J.P.; Brink, H.M. ten

1998-01-01

Crystallisation of laboratory aerosols of ammonium nitrate and of internal mixtures of this salt with ammonium sulphate were investigated using humidity controlled nephelometry. The aerosol was produced via nebulizing of solutions and then dried to 25% RH, which is a realistic minimum value for

Phosphate glasses, containing nitrogen

International Nuclear Information System (INIS)

Lisitsyna, E.A.; Khalilev, V.D.; Koryavin, A.A.; Goncharova, L.N.

1987-01-01

Possibilities of nitrogen-containing glass synthesis by the introduction into the charge of ammonium salts, as well as aluminium nitride, are studied. Zinc alumoyttrium phosphate glass (mol. %) Zn(PO 3 ) 2 - 4O, Al(PO 3 ) 3 - 3O, Y(PO 3 ) 3 -3O is suggested as a matrix. It is shown that the effect of amide and imide groups on the properties of the glass is less noticeable than the effect of nitride groups. Direct introduction of nitride constituent was realized using AlN, but aluminium introduction was taken into account so that the oxide was subtracted. The attempt to introduce more than 2.5 mass % of nitrogen into initial matrix by aluminium nitride has failed due to repeated restoration of glass with amorphous phosphorus isolation

Magnesium Hydroxide

Science.gov (United States)

Magnesium hydroxide is used on a short-term basis to treat constipation.This medication is sometimes prescribed ... Magnesium hydroxide come as a tablet and liquid to take by mouth. It usually is taken as ...

Ferrous ammonium phosphate (FeNH₄PO₄) as a new food fortificant: iron bioavailability compared to ferrous sulfate and ferric pyrophosphate from an instant milk drink.

Science.gov (United States)

Walczyk, Thomas; Kastenmayer, Peter; Storcksdieck Genannt Bonsmann, Stefan; Zeder, Christophe; Grathwohl, Dominik; Hurrell, Richard F

2013-06-01

The main purpose of this study was to establish bioavailability data in humans for the new (Fe) fortification compound ferrous ammonium phosphate (FAP), which was specially developed for fortification of difficult-to-fortify foods where soluble Fe compounds cannot be used due to their negative impact on product stability. A double-blind, randomized clinical trial with cross-over design was conducted to obtain bioavailability data for FAP in humans. In this trial, Fe absorption from FAP-fortified full-cream milk powder was compared to that from ferric pyrophosphate (FPP) and ferrous sulfate. Fe absorption was determined in 38 young women using the erythrocyte incorporation dual stable isotope technique (⁵⁷Fe, ⁵⁸Fe). Geometric mean Fe absorption from ferrous sulfate, FAP and FPP was 10.4, 7.4 and 3.3 %, respectively. Fe from FAP was significantly better absorbed from milk than Fe from FPP (p soluble reference compound (p = 0.0002). Absorption ratios of FAP and FPP relative to ferrous sulfate as a measure of relative bioavailability were 0.71 and 0.32, respectively. The results of the present studies show that replacing FPP with FAP in full-cream milk could significantly improve iron bioavailability.

Research Progress in Plasma arc welding of Magnesium Alloys and Magnesium Matrix Composites

Science.gov (United States)

Hui, Li; Yang, Zou; Yongbo, Li; Lei, Jiao; Ruijun, Hou

2017-11-01

Magnesium alloys and magnesium matrix composites by means of its excellent performance have wide application prospect in electronics, automotive, biotechnology, aerospace field, and welding technology has become a key of restricting its application. This paper describes the welding characteristics of magnesium, the obvious advantages in the application and the domestic and foreign research advance technology of plasma arc welding of magnesium, and summarizes the existing problems and development trends of plasma arc welding technology of magnesium.

49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

Science.gov (United States)

2010-10-01

... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more than...

FOCUS ON MAGNESIUM BASED DRUGS

Directory of Open Access Journals (Sweden)

I. I. Esenova

2011-01-01

Full Text Available Magnesium deficiency in the organism is one of the most common human deficiency states. The prevalence of magnesium deficiency is about 15%, and suboptimal magnesium level is observed more than in 30% of people in the general population. Clinical signs of hypomagnesaemia are observed in 40% of patients in general care hospitals, in 70% of patients - in intensive care units, and magnesium deficiency occurs in 90% of patients with acute coronary syndrome. Magnesium metabolic disorders in the organism accelerate significantly development of complications of coronary heart disease, hypertension, type 2 diabetes, asthma and a number of neurological and psychiatric diseases. The value of this macro in the body is well studied, and its daily need is identified depending on age and sex. It is known that magnesium intake with the food does not cover an organism need. It is a rationale for preventive and therapeutic use of magnesium based drugs in various diseases. Organic salts of magnesium are recommended for these purposes. Magnesium metabolic disorders, approaches to pharmacotherapeutic correction of magnesium deficiency, advantages of magnesium salts of orotic acid are reviewed.

Waterproofing Materials for Ammonium Nitrate

OpenAIRE

R.S. Damse

2004-01-01

This study explores the possibility of overcoming the problem of hygroscopicity of ammonium nitrate by coating the particles with selected waterproofing materials. Gravimetric analysis ofthe samples of ammonium nitrate coated with eight different waterproofing materials, vis-a-vis, uncoated ammonium nitrate, were conducted at different relative humidity and exposuretime. The results indicate that mineral jelly is the promising waterproofing material for ammonium nitrate among the materials te...

49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

Science.gov (United States)

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. 176.410 Section 176.410 Transportation Other Regulations Relating to... nitrate and ammonium nitrate mixtures. (a) This section prescribes requirements to be observed with...

Ammonium-induced inhibition of ammonium-starved Nitrosomonas europaea cells in soil and sand slurries

NARCIS (Netherlands)

Gerards, S.; Duyts, H.; Laanbroek, H.J.

1998-01-01

Ammonia-oxidising bacteria are poor competitors for limiting amounts of ammonium. Hence, starvation for ammonium seems to be the regular condition for these bacteria in natural environments. Long-term survival in the absence of ammonium will be dependent on the ability to maintain large population

Magnesium Oxide

Science.gov (United States)

Magnesium is an element your body needs to function normally. Magnesium oxide may be used for different reasons. Some people use it as ... one to four times daily depending on which brand is used and what condition you have. Follow ...

Post-Digestion Liquor Treatment in the Method Combining Chemical Precipitation with Reverse Osmosis

Directory of Open Access Journals (Sweden)

Kuglarz Mariusz

2014-12-01

Full Text Available The aim of the study was to develop an effective treatment of post-digestion liquors highly-loaded with biogenic and organic substances. The scope of the research project encompassed: mesophilic anaerobic digestion of waste activated sludge (WAS as well as the treatment of post-digestion liquors, coming from the most appropriate HRT value of 25 days, in the process of ammonium magnesium phosphate (struvite precipitation targeted at ammonia nitrogen binding and a subsequent reverse osmosis (RO process. It was established that the method combining chemical precipitation and high-pressure filtration ensures a high degree of contaminants removal allowing for a direct release of treated liquors into the natural reservoir. However, in order to decrease the residual NH4+ concentration (6.1 mg NH4+/dm3 in the purified post-digestion liquors below the level allowing for a direct release to the natural reservoir, it turned out to be necessary to apply increased molar ratio of magnesium and phosphates (Mg:NH4+: PO43-= 1.5:1:1.5.

EFFECT OF INTEGRATED SOIL FERTILITY MANAGEMENT INTERVENTIONS ON THE ABUNDANCE AND DIVERSITY OF SOIL COLLEMBOLA IN EMBU AND TAITA DISTRICTS, KENYA

Directory of Open Access Journals (Sweden)

Jamleck Muturi

2010-10-01

Full Text Available The study aimed at identifying soil fertility management practices that promote the Collembola population, diversity and survival in the soil. Soil samples were randomly collected from on farm plots amended with: 1-Mavuno ((Ma-is a compound fertilizer containing 26% Potassium, 10% Nitrogen, 10% Calcium, 4% Sulphur, 4% Magnesium and trace elements like Zinc, Copper, Boron, Molybdenum and Manganese, 2-Manure (Mn, 3-Trichoderna (Tr inoculant (is a soil and compost-borne antagonistic fungus used as biological control agent against plant fungal diseases, 4-Farmers practice ((FP where Tripple Super Phosphate (T.S.P. and Calcium Ammonium Nitrate (C.A.N. fertilizers are applied in the soil in mixed form, 5-Tripple Super Phosphate (T.S.P., 6-Calcium Ammonium Nitrate (C.A.N.. These treatments were compared with 7-Control (Co (where soil fertility management interventions where not applied. Soil Collembola were extracted using dynamic behavioural modified Berlese funnel and identified to the genus level. Occurrence of Collembola was significantly affected by soil fertility amendments in both Taita and Embu study sites (P

REMOVE AND RELEASE OF NUTRIENTS AFTER HYBRID PRE-TREATMENT OF ACTIVATED SLUDGE FOAM

Directory of Open Access Journals (Sweden)

Alicja Machnicka

2017-02-01

Full Text Available One of the problems in wastewater treatment technologies is the formation of foam/scum on the surface of bioreactors. The foam elimination/destruction can be carried out by various methods among which disintegration is included. Hybrid disintegration (chemical decomposition and hydrodynamic cavitation of the foam microorganisms results in phosphates, ammonium nitrogen, magnesium and potassium transferred from the foam solids into the liquid phase. Application of both methods as a hybrid pre-treatment process caused in an increased concentration of phosphates of about 677 mg PO43- L-1, ammonium nitrogen about 41 mg N-NH4+ L-1. The concentration of Mg2+ and K+ in the solution increased from 6.2 to 31.1 mg Mg2+ L-1 and from 22.4 to 102.0 mg K+ L-1, respectively. The confirmation of physicochemical changes and release of cellular matter as a result of cellular lysis (hybrid disintegration was IR analysis. It was demonstrated that the disintegration of foam permits removal of a part of nutrients in the form of struvite.

Magnesium motorcycle applications

International Nuclear Information System (INIS)

Jianyong Cao; Zonghe Zhang; Dongxia Xiang; Jun Wang

2005-01-01

Magnesium, the lightest engineering structural metal, has been comprehensively used in castings of aviation and aerospace, communication and transportation, and IT components. This paper introduced the history, advantages and difficulties of magnesium castings for motorcycle application as well as its application state in China. It also indicated the production situation of magnesium motorcycle components in CQMST and difficulties need to overcome for further development. (orig.)

Characterization and corrosion behavior of ceramic coating on magnesium by micro-arc oxidation

International Nuclear Information System (INIS)

Durdu, Salih; Aytac, Aylin; Usta, Metin

2011-01-01

Highlights: · The commercial pure magnesium was coated by micro-arc oxidation method. · The coating is composed of two layers, a porous outer layer and a dense inner layer. · A super corrosion resistance was achieved with MAO coatings. · Coating with Mg 2 SiO 4 is more resistant to corrosion than that containing Mg 3 (PO 4 ) 2 . - Abstract: In this study, the commercial pure magnesium was coated in different aqueous solutions of Na 2 SiO 3 and Na 3 PO 4 by the micro-arc oxidation method (MAO). Coating thickness, phase composition, surface and cross sectional morphology and corrosion resistance of coatings were analyzed by eddy current method, X-ray diffraction (XRD), scanning electron microscope (SEM) and tafel extrapolation method, respectively. The average thickness of the coatings ranged from 52 to 74 μm for sodium silicate solution and from 64 to 88 μm for sodium phosphate solution. The dominant phases on the coatings were detected as spinal Mg 2 SiO 4 (Forsterite) and MgO (Periclase) for sodium silicate solution and Mg 3 (PO 4 ) 2 (Farringtonite) and MgO (Periclase) for sodium phosphate solution. SEM images reveal that the coating is composed of two layers as of a porous outer layer and a dense inner layer. The corrosion results show the coating consisting Mg 2 SiO 4 is more resistant to corrosion than that containing Mg 3 (PO 4 ) 2 .

Magnesium sulfate reduces formalin-induced orofacial pain in rats with normal magnesium serum levels.

Science.gov (United States)

Srebro, Dragana P; Vučković, Sonja M; Dožić, Ivan S; Dožić, Branko S; Savić Vujović, Katarina R; Milovanović, Aleksandar P; Karadžić, Branislav V; Prostran, Milica Š

2018-02-01

In humans, orofacial pain has a high prevalence and is often difficult to treat. Magnesium is an essential element in biological a system which controls the activity of many ion channels, neurotransmitters and enzymes. Magnesium produces an antinociceptive effect in neuropathic pain, while in inflammatory pain results are not consistent. We examined the effects of magnesium sulfate using the rat orofacial formalin test, a model of trigeminal pain. Male Wistar rats were injected with 1.5% formalin into the perinasal area, and the total time spent in pain-related behavior (face rubbing) was quantified. We also spectrophotometrically determined the concentration of magnesium and creatine kinase activity in blood serum. Magnesium sulfate administered subcutaneously (0.005-45mg/kg) produced significant antinociception in the second phase of the orofacial formalin test in rats at physiological serum concentration of magnesium. The effect was not dose-dependent. The maximum antinociceptive effect of magnesium sulfate was about 50% and was achieved at doses of 15 and 45mg/kg. Magnesium did not affect increase the levels of serum creatine kinase activity. Preemptive systemic administration of magnesium sulfate as the only drug can be used to prevent inflammatory pain in the orofacial region. Its analgesic effect is not associated with magnesium deficiency. Copyright © 2017 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Function of magnesium aluminate hydrate and magnesium nitrate ...

Indian Academy of Sciences (India)

MgO was added both as spinel (MgAl2O4) forming precursor i.e. magnesium aluminate hydrate, and magnesium nitrate. Sintering investigations were conducted in the temperature range 1500–1600°C with 2 h soaking. Structural study of sintered pellets was carried out by extensive XRD analysis. Scanning electron mode ...

Magnesium compounds

Science.gov (United States)

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.

Data on snow chemistry of the Cascade-Sierra Nevada Mountains

Science.gov (United States)

Laird, L.B.; Taylor, Howard E.; Lombard, R.E.

1986-01-01

Snow chemistry data were measured for solutes found in snow core samples collected from the Cascade-Sierra Nevada Mountains from late February to mid-March 1983. The data are part of a study to assess geographic variations in atmospheric deposition in Washington, Oregon, and California. The constituents and properties include pH and concentrations of hydrogen ion, calcium, magnesium, sodium, potassium, chloride, sulfate, nitrate, fluoride, phosphate, ammonium, iron, aluminum, manganese, copper, cadmium, lead, and dissolved organic carbon. Concentrations of arsenic and bromide were below the detection limit. (USGS)

Preparation and thermogravimetric study of some uranyl phosphates

International Nuclear Information System (INIS)

Schaekers, J.M.

1970-10-01

The preparation of uranyl ammonium phosphate trihydrate (UAP = UO 2 NH 4 PO 4 .3H 2 O), acid uranyl phosphate tetrahydrate(AUP = UO 2 HPO 4 .4H 2 O) and neutral uranyl phosphate tetrahydrate (NUPT = (UO 2 ) 3 (PO 4 ) 2 .4H 2 O) was investigated during the data from the literature. The thermal decomposition in different atmospheres, such as air, oxygen, nitrogen and argon, was studied in the temperature range 25-1000 0 C. It was found that the pyrophosphate U 2 O 3 P 2 O 7 is a stable decomposition product of UAP as well as of AUP. A mixture of U 3 O 8 and U 2 O 3 P 2 O 7 is obtained when the NUPT is decomposed in an oxygen-free atmosphere. NUPT however is stable in an oxidising atmosphere. Hydrogen and carbon reductions were also carried out, and UO 2 or (UO) 2 P 2 O 7 as well as mixtures of these two products can be obtained, depending on the starting material and the reduction temperature. The different reduction and decomposition reactions were studied by means of thermogravimetric analysis, and activation energies were calculated where possible. I.R. spectral analysis was also used to identify various products with the same composition [af

Removal of lead and phosphate ions from aqueous solutions by organo-smectite.

Science.gov (United States)

Bajda, Tomasz; Szala, Barbara; Solecka, Urszula

2015-01-01

Smectite has been modified using hexadecyltrimethyl ammonium bromide in an amount of double cationic exchange capacity. This alteration makes it possible to use organo-smectite as a sorbent to remove anionic forms. The experiment consisted of the interchangeable sorption of phosphate(V) and lead(II) by organo-smectite. Research was carried out with varying pH (2-5) and various concentrations (0.1-5 mmol/L). Organo-smectite with previously adsorbed lead ions removed more phosphate than the untreated organo-smectite. Experimental data show that lead is more likely to absorb on the organo-smectite than on the organo-smectite with previously adsorbed phosphate ions. It follows that the most effective use of the organo-smectite is through the sorption of first - Pb cations and then PO4 anions. With an increasing concentration of Pb(II) or P(V), the sorption efficiency increases. The maximum sorption efficiency of lead and phosphate ions is observed at pH 5. This enables the removal of harmful lead and phosphorus compounds from waste water and immobilizes them on the sorbent's surface. The alternating reactions of lead and phosphorus ions result in the crystallization of brompyromorphite Pb5(PO4)3Br.

The Australian national reactive phosphate rock project - Aims, experimental approach, and site characteristics

International Nuclear Information System (INIS)

McLaughlin, M.J.

2002-01-01

Field-based cutting trials were established across Australia in a range of environments to evaluate the agronomic effectiveness of 5 phosphate rocks, and 1 partially acidulated phosphate rock, relative to either single super-phosphate or triple superphosphate. The phosphate rocks differed in reactivity, as determined by the degree of carbonate substitution for phosphate in the apatite structure and solubility of phosphorus present in the fertilizers in 2% formic acid, 2% citric acid and neutral ammonium citrate. Sechura (Bayovar) and North Carolina phosphate rocks were highly reactive (>70% solubility in 2% formic acid), whilst Khouribja (Moroccan) and Hamrawein (Egypt) phosphate rock were moderately reactive. Duchess phosphate rock from Queensland was relatively unreactive ( 2 , from 4.0 to 5.1, and Colwell extractable phosphorus ranged from 3 to 47 μg/g prior to fertilizer application. Two core experiments were established at each site. The first measured the effects of phosphate rock reactivity on agronomic effectiveness, while the second core experiment measured the effects of the degree of water solubility of the phosphorus source on agronomic effectiveness. The National Reactive Phosphate Rock Project trials provided the opportunity to confirm the suitability of accepted procedures to model fertilizer response and to develop new approaches for comparing different fertilizer responses. The Project also provided the framework for subsidiary studies such as the effect of fertilizer source on soil phosphorus extractability; cadmium and fluorine concentrations in herbage; evaluation of soil phosphorus tests; and the influence of particle size on phosphate rock effectiveness. The National Reactive Phosphate Rock Project presents a valuable model for a large, Australia-wide, collaborative team approach to an important agricultural issue. The use of standard and consistent experimental methodologies at every site ensured that maximum benefit was obtained from data

Innovative Vacuum Distillation for Magnesium Recycling

Science.gov (United States)

Zhu, Tianbai; Li, Naiyi; Mei, Xiaoming; Yu, Alfred; Shang, Shixiang

Magnesium recycling now becomes a very important subject as magnesium consumption increases fast around the world. All commonly used magnesium die-casting alloys can be recycled and recovered to the primary metal quality. The recycled materials may be comprised of biscuits, sprues, runners, flash, overflows, dross, sludge, scrap parts, and old parts that are returned from service, An innovative magnesium recycle method, vacuum distillation, is developed and proved out to be able to recycle magnesium scraps, especially machining chips, oily magnesium, smelting sludge, dross or the mixture. With this process at a specific temperature and environment condition, magnesium in scraps can be gasified and then solidified to become crystal magnesium crown. This `recycled' magnesium crown is collected and used as the raw material of magnesium alloys. The experimental results show the vacuum distillation is a feasible and plausible method to recycle magnesium. Further, the cost analysis will be addressed in this paper.

INVESTIGATION OF MAGNESIUM ALLOYS MACHINABILITY

Directory of Open Access Journals (Sweden)

Berat Barıs BULDUM

2013-01-01

Full Text Available Magnesium is the lightest structural metal. Magnesium alloys have a hexagonal lattice structure, which affects the fundamental properties of these alloys. Plastic deformation of the hexagonal lattice is more complicated than in cubic latticed metals like aluminum, copper and steel. Magnesium alloy developments have traditionally been driven by industry requirements for lightweight materials to operate under increasingly demanding conditions. Magnesium alloys have always been attractive to designers due to their low density, only two thirds that of aluminium and its alloys [1]. The element and its alloys take a big part of modern industry needs. Especially nowadays magnesium alloys are used in automotive and mechanical (trains and wagons manufacture, because of its lightness and other features. Magnesium and magnesium alloys are the easiest of all metals to machine, allowing machining operations at extremely high speed. All standard machining operations such as turning, drilling, milling, are commonly performed on magnesium parts.

Efficiency of ammonium nitrate phosphates of varying water-soluble phosphorous content for wheat and succeeding maize crop on different soil types

International Nuclear Information System (INIS)

Chapke, V.G.; Bhujbal, B.M.; Mistry, K.B.

1988-01-01

Efficiency of 32 P labelled ammonium nitrate phosphate (ANP) containding 30, 50 and 90 per cent of water-soluble phosphorus (WSP) vis-a-vis that of entirely water soluble monoammonium orthophosphate (MAP) for wheat and succeeding maize crop on deep black (vertisol), calcareous black (vertisol), alluvial-Tarai (mollisol) and grey brown alluvial (aridisol) soils was examined in greenhouse experiments. Data on wheat indicated that ANP (50 per cent WSP) was, in general, equally efficient to MAP and ANP (90 per cent WSP) in terms of drymatter yield and total uptake of phosphorus in all soils examined, however, the per cent utilization of applied fertilizer was significantly higher for MAP and ANP (90 per cent WSP) than those for ANP (50 per cent WSP) in all soils. In general, ANP (30 per cent WSP) was significantly inferior to MAP and ANP (90 per cent WSP) in all soils. Data on the succeeding maize crop grown to flowering indicated that residual value of ANP (30 per cent WSP) was equal to that of MAP and ANP (90 per cent WSP) in terms of drymatter yield and phosphorus uptake by the four soils examined. Complementary incubation studies conducted upto 60 days on the above four soils at field capacity moisture status indicated highest 0.5 M NaHCO 3 (pH 8.5) extractable phosphorus levels in MAP treatments followed by ANP (50 per cent WSP) and least in ANP (30 per cent WSP) treatments. (author). 4 tables, 4 figures, 19 refs

Standard characterization of phosphate rock samples from the FAO/IAEA phosphate project

International Nuclear Information System (INIS)

Binh, Truong; Zapata, F.

2002-01-01

Phosphate rocks (PR) are phosphate-bearing minerals that vary widely in their inherent characteristics and consequently their agronomic potential. In the framework of a FAO/IAEA networked research project, the evaluation of the agronomic effectiveness of natural and modified PR products under a variety of soil climate and crop management conditions was carried out. The characterization of phosphate rocks is the first and essential step in evaluating their suitability for direct application. If several PR sources are utilized, standardized methods should be used for comparison purposes to determine their agronomic potential. This paper describes the standard characterization of phosphate rock products utilized in the project, in particular the mineralogical and crystallographic analyses, physical analyses, chemical composition and solubility in conventional reagents. A total of 28 phosphate rock samples from 15 countries were collected and analyzed in specialized laboratories. The data on mineralogy, chemical composition and solubility in conventional reagents are closely interrelated. An arbitrary classification of the reactivity of the PR samples was made based on the solubility indices in conventional reagents. On another hand, the results of the crystallographic parameters, calculated indices of absolute solubility, specific surface and porosity reflect the variability of the physical state and the sample pre-conditioning treatment of the analyzed products. A proper characterization of phosphate rock samples should provide the maximum of basic information that can be obtained in a cost-effective manner in normal chemical laboratories. Based on the results of this characterization, the following determinations are recommended: a description of the sample, major elemental (total P, Ca, Mg) composition, solubility in conventional reagents (neutral ammonium citrate, citric and formic acid) and particle size analysis. The classification of PR samples for direct

Comparison of electrochemical corrosion behaviour of MgO and ZrO2 coatings on AM50 magnesium alloy formed by plasma electrolytic oxidation

International Nuclear Information System (INIS)

Liang, J.; Srinivasan, P. Bala; Blawert, C.; Dietzel, W.

2009-01-01

Two types of PEO coatings were produced on AM50 magnesium alloy using pulsed DC plasma electrolytic oxidation process in an alkaline phosphate and acidic fluozirconate electrolytes, respectively. The phase composition and microstructure of these PEO coatings were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The corrosion behaviour of the coated samples was evaluated by open circuit potential (OCP) measurements, potentiodynamic polarization tests, and electrochemical impedance spectroscopy (EIS) in neutral 0.1 M NaCl solution. The results showed that PEO coating prepared from alkaline phosphate electrolyte consisted of only MgO and on the other hand the one formed in acidic fluozirconate solution was mainly composed of ZrO 2 , MgF 2 . Electrochemical corrosion tests indicated that the phase composition of PEO coating has a significant effect on the deterioration process of coated magnesium alloy in this corrosive environment. The PEO coating that was composed of only MgO suffered from localized corrosion in the 50 h exposure studies, whereas the PEO coating with ZrO 2 compounds showed a much superior stability during the corrosion tests and provided an efficient corrosion protection. The results showed that the preparation of PEO coating with higher chemical stability compounds offers an opportunity to produce layers that could provide better corrosion protection to magnesium alloys.

Effects of Aromatic Ammoniums on Methyl Ammonium Lead Iodide Hybrid Perovskite Materials

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Jianli Yang

2017-01-01

Full Text Available The introduction of bulky ammoniums into methyl ammonium lead iodide hybrid perovskites (MAPbI3 has emerged as a promising strategy to improve the properties of these materials. In the present work, we studied the effects of several aromatic ammoniums onto the structural, electronic, and optical properties of MAPbI3. Although powder XRD data suggest that the bulky cations are not involved in the bulk phase of the MAPbI3, a surprisingly large effect of the bulky cations onto the photoluminescence properties was observed.

Novel Ammonium Metal Borohydrides

DEFF Research Database (Denmark)

Grinderslev, Jakob; Jepsen, Lars Haahr; Cerny, Radovan

, it cannot store hydrogen reversibly. Recently, the first ammonium metal borohydride, NH4Ca(BH4)3 was published, which may be considered as substitution of K+ by NH4+ in KCa(BH4)3, due to the similar sizes of NH4+ and K+[1]. This compound successfully stabilizes NH4BH4. In the present work, a series of novel...... halide-free ammonium metal borohydrides is presented, which have the chemical compositions (NH4)xM(BH4)n+x. The ammonium metal borohydrides are synthesized by cryomilling of NH4BH4 – M(BH4)n (M = Li, Na, K, Mg, Sr, Y, Mn, La, Gd) in different ratios. A new range of ammonium metal borohydrides is formed......, and the crystal structures and thermal decompositions are investigated. Mixtures of NH4BH4 - NaBH4 do not react, while solid solutions, K1-x(NH4)xBH4, are formed for NH4BH4 - KBH4. For the other composites, novel ammonium metal borohydrides are formed. Several of these structures have been solved from high...

Development and Validation of RP-HPLC Method for Simultaneous Estimation of Aspirin and Esomeprazole Magnesium in Tablet Dosage Form

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Dipali Patel

2013-01-01

Full Text Available A simple, specific, precise, and accurate reversed-phase HPLC method was developed and validated for simultaneous estimation of aspirin and esomeprazole magnesium in tablet dosage forms. The separation was achieved by HyperChrom ODS-BP C18 column (200 mm × 4.6 mm; 5.0 μm using acetonitrile: methanol: 0.05 M phosphate buffer at pH 3 adjusted with orthophosphoric acid (25 : 25 : 50, v/v as eluent, at a flow rate of 1 mL/min. Detection was carried out at wavelength 230 nm. The retention times of aspirin and esomeprazole magnesium were 4.29 min and 6.09 min, respectively. The linearity was established over the concentration ranges of 10–70 μg/mL and 10–30 μg/mL with correlation coefficients (r2 0.9986 and 0.9973 for aspirin and esomeprazole magnesium, respectively. The mean recoveries were found to be in the ranges of 99.80–100.57% and 99.70–100.83% for aspirin and esomeprazole magnesium, respectively. The proposed method has been validated as per ICH guidelines and successfully applied to the estimation of aspirin and esomeprazole magnesium in their combined tablet dosage form.

Purification of molybdenum

International Nuclear Information System (INIS)

Cheresnowsky, M.J.; Brunelli, T.A.; Kim, T.K.

1987-01-01

A method for purifying molybdenum is described comprising: (a) adding to an ammoniacal ammonium molybdate solution which is at a pH of from about 8.5 to about 11 and which contains the impurities of phosphorus and arsenic with the phosphorus concentration being from about 0.01 to about 0.12 g/l, a soluble magnesium salt to form a precipitate comprising magnesium ammonium salts of the phosphorus and the arsenic, and to form a purified ammonium molybdate solution, with the amount of the magnesium salt being added in an amount sufficient to result in a concentration of from about 0.005 to about 0.04 moles Mg/l in the ammoniacal ammonium molybdate solution, and the purified solution containing no greater than about 0.01 g P/l; (b) separating the precipitate from the purified ammonium molybdate solution; and (c) contacting the purified ammonium molybdate solution with a chelating cation exchange resin supplying a sufficient amount of ammonium as the cation to remove the major portion of the magnesium ions from the purified solution and form a further purified ammonium molybdate solution

21 CFR 184.1138 - Ammonium chloride.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium chloride. 184.1138 Section 184.1138 Food... Specific Substances Affirmed as GRAS § 184.1138 Ammonium chloride. (a) Ammonium chloride (NH4Cl, CAS Reg. No. 12125-02-9) is produced by the reaction of sodium chloride and an ammonium salt in solution. The...

Elevated dietary magnesium during pregnancy and postnatal life prevents ectopic mineralization in Enpp1asj mice, a model for generalized arterial calcification of infancy.

Science.gov (United States)

Kingman, Joshua; Uitto, Jouni; Li, Qiaoli

2017-06-13

Generalized arterial calcification of infancy (GACI) is an autosomal recessive disorder caused by mutations in the ENPP1 gene. It is characterized by mineralization of the arterial blood vessels, often diagnosed prenatally, and associated with death in early childhood. There is no effective treatment for this devastating disorder. We previously characterized the Enpp1asjmutant mouse as a model of GACI, and we have now explored the effect of elevated dietary magnesium (five-fold) in pregnant mothers and continuing for the first 14 weeks of postnatal life. The mothers were kept on either control diet or experimental diet supplemented with magnesium. Upon weaning at 4 weeks of age the pups were placed either on control diet or high magnesium diet. The degree of mineralization was assessed at 14 weeks of age by histopathology and a chemical calcium assay in muzzle skin, kidney and aorta. Mice placed on high magnesium diet showed little, if any, evidence of mineralization when their corresponding mothers were also placed on diet enriched with magnesium during pregnancy and nursing. The reduced ectopic mineralization in these mice was accompanied by increased calcium and magnesium content in the urine, suggesting that magnesium competes calcium-phosphate binding thereby preventing the mineral deposition. These results have implications for dietary management of pregnancies in which the fetus is suspected of having GACI. Moreover, augmenting a diet with high magnesium may be beneficial for other ectopic mineralization diseases, including nephrocalcinosis.

Magnesium compounds

Science.gov (United States)

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.

Magnesium-based implants: a mini-review.

Science.gov (United States)

Luthringer, Bérengère J C; Feyerabend, Frank; Willumeit-Römer, Regine

2014-01-01

The goal of this review is to bring to the attention of the readership of Magnesium Research another facet of the importance of magnesium, i.e. magnesium-based biomaterials. A concise history of biomaterials and magnesium are thus presented. In addition, historical and current, clinical magnesium-based applications are presented.

Development of an automated flow injection analysis system for determination of phosphate in nutrient solutions.

Science.gov (United States)

Karadağ, Sevinç; Görüşük, Emine M; Çetinkaya, Ebru; Deveci, Seda; Dönmez, Koray B; Uncuoğlu, Emre; Doğu, Mustafa

2018-01-25

A fully automated flow injection analysis (FIA) system was developed for determination of phosphate ion in nutrient solutions. This newly developed FIA system is a portable, rapid and sensitive measuring instrument that allows on-line analysis and monitoring of phosphate ion concentration in nutrient solutions. The molybdenum blue method, which is widely used in FIA phosphate analysis, was adapted to the developed FIA system. The method is based on the formation of ammonium Mo(VI) ion by reaction of ammonium molybdate with the phosphate ion present in the medium. The Mo(VI) ion then reacts with ascorbic acid and is reduced to the spectrometrically measurable Mo(V) ion. New software specific for flow analysis was developed in the LabVIEW development environment to control all the components of the FIA system. The important factors affecting the analytical signal were identified as reagent flow rate, injection volume and post-injection flow path length, and they were optimized using Box-Behnken experimental design and response surface methodology. The optimum point for the maximum analytical signal was calculated as 0.50 mL min -1 reagent flow rate, 100 µL sample injection volume and 60 cm post-injection flow path length. The proposed FIA system had a sampling frequency of 100 samples per hour over a linear working range of 3-100 mg L -1 (R 2  = 0.9995). The relative standard deviation (RSD) was 1.09% and the limit of detection (LOD) was 0.34 mg L -1 . Various nutrient solutions from a tomato-growing hydroponic greenhouse were analyzed with the developed FIA system and the results were found to be in good agreement with vanadomolybdate chemical method findings. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Desiccator Volume: A Vital Yet Ignored Parameter in CaCO3 Crystallization by the Ammonium Carbonate Diffusion Method

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Joe Harris

2017-07-01

Full Text Available Employing the widely used ammonium carbonate diffusion method, we demonstrate that altering an extrinsic parameter—desiccator size—which is rarely detailed in publications, can alter the route of crystallization. Hexagonally packed assemblies of spherical magnesium-calcium carbonate particles or spherulitic aragonitic particles can be selectively prepared from the same initial reaction solution by simply changing the internal volume of the desiccator, thereby changing the rate of carbonate addition and consequently precursor formation. This demonstrates that it is not merely the quantity of an additive which can control particle morphogenesis and phase selectivity, but control of other often ignored parameters are vital to ensure adequate reproducibility.

Ionized magnesium in plasma and erythrocytes for the assessment of low magnesium status in alcohol dependent patients.

Science.gov (United States)

Ordak, Michal; Maj-Zurawska, Magdalena; Matsumoto, Halina; Bujalska-Zadrozny, Magdalena; Kieres-Salomonski, Ilona; Nasierowski, Tadeusz; Muszynska, Elzbieta; Wojnar, Marcin

2017-09-01

Studies on the homeostasis of magnesium in alcohol-dependent patients have often been characterized by low hypomagnesemia detection rates. This may be due to the fact that the content of magnesium in blood serum constitutes only 1% of the average magnesium level within the human body. However, the concentration of ionized magnesium is more physiologically important and makes up 67% of the total magnesium within a human organism. There are no data concerning the determination of the ionized fraction of magnesium in patients addicted to alcohol and its influence on mental health status. This study included 100 alcohol-dependent patients and 50 healthy subjects. The free magnesium fraction was determined using the potentiometric method by means of using ion-selective electrodes. The total magnesium level was determined by using a biochemical Indiko Plus analyzer. In this study, different psychometric scales were applied. Our results confirm the usefulness of ionized magnesium concentrations in erythrocytes and plasma as a diagnostic parameter of low magnesium status in alcohol-dependent patients. The lower the concentration of ionized magnesium, the worse the quality of life an alcohol-dependent person might experience. In the case of total magnesium, no such correlation was determined. Copyright © 2017 Elsevier B.V. All rights reserved.

Novel Ammonium Metal Borohydrides

DEFF Research Database (Denmark)

Grinderslev, Jakob; Jepsen, Lars Haahr; Cerny, Radovan

Ammonium borohydride, NH4BH4, has a very high gravimetric (ρm = 24.5 wt% H2) and volumetric (157.3 g·H2/L) hydrogen content and releases 18.4 wt% H2 below 170 °C. However, NH4BH4 is metastable at RT and ambient pressure, with a half-life of ~6 h. The decomposition is strongly exothermic; therefore......, it cannot store hydrogen reversibly. Recently, the first ammonium metal borohydride, NH4Ca(BH4)3 was published, which may be considered as substitution of K+ by NH4+ in KCa(BH4)3, due to the similar sizes of NH4+ and K+[1]. This compound successfully stabilizes NH4BH4. In the present work, a series of novel...... halide-free ammonium metal borohydrides is presented, which have the chemical compositions (NH4)xM(BH4)n+x. The ammonium metal borohydrides are synthesized by cryomilling of NH4BH4 – M(BH4)n (M = Li, Na, K, Mg, Sr, Y, Mn, La, Gd) in different ratios. A new range of ammonium metal borohydrides is formed...

Investigation of alternative phosphating treatments for nickel and hexavalent chromium elimination

International Nuclear Information System (INIS)

Jazbinsek, Luiz Antonio Rossi

2014-01-01

The phosphating processes are widely used in industry as surface treatments for metals, especially for low thickness plates, improving the adhesion between the metallic surface and the paint coating, and increasing the durability of paint systems against corrosion attacks. The tricationic phosphates containing zinc, nickel and manganese are commonly applied on steel. There is much discussion about the replacement of nickel by another element in order to have an environmentally friendly phosphating process. Niobium as a replacement for nickel has been evaluated. The most significant environmental impacts of phosphating processes are related to the presence of nickel and hexavalent chromium used in the process, this last as a passivation treatment. Nickel and hexavalent chromium are harmful to human and environment leading to contamination of water and soil. In the present study phosphate layers containing zinc, manganese and niobium have been evaluated and characterized on galvanized steel, and the results were compared with phosphates containing zinc, manganese and nickel, or a bicationic phosphate layer with zinc and manganese. Although the use of hexavalent chromium is not recommended worldwide, it is still used in processes for sealing the porosity of phosphate layers. This element is carcinogenic and has been associated with various diseases. Due to the passivation characteristics of niobium, this study also evaluated the tricationic bath containing niobium ammonium oxalate as a passivation treatment. The results showed that it could act as a replacement for the hexavalent chromium. The results of the present study showed that formulations containing niobium are potential replacements for hexavalent chromium and similar corrosion protection was obtained for the phosphate containing nickel or that with niobium. The morphology observed by scanning electron microscopy, gravimetric tests, porosity and adhesion evaluation results indicated that the phosphate

Choline Magnesium Trisalicylate

Science.gov (United States)

Choline magnesium trisalicylate is used to relieve the pain, tenderness, inflammation (swelling), and stiffness caused by arthritis and painful ... used to relieve pain and lower fever. Choline magnesium trisalicylate is in a class of nonsteroidal anti- ...

Uranium extraction from ores with salicylic acid; I - uranium extraction from input phosphate ore of Abu Zaabal phosphate plant, Egypt

International Nuclear Information System (INIS)

Hussein, E.M.

1997-01-01

Salicylic acid has been tested (for environmental importance) to extract U from input phosphate ore of Abu-Zaabal phosphate plant, Egypt prior to its processing for production of phosphatic fertilizers. Uranyl ion forms with this acid three stable complexes; namely [UO 2 Sal] degree, [U O 2 SaL 2 ] 2- and UO 2 SaL-3] 4- depending on the total uranyl and salicylic acid concentrations and their ratios. Study of relevant extraction factors revealed however that, the extraction process is controlled by the amount of salicylic acid used, alcohol/aqueous ratio, solid/liquid ratio and time of agitation. The obtained results showed that uranium is selectively leached by the application of such a leaching reagent. In order to recover U from the obtained pregnant leach liquor, the latter is adjusted by ammonia to PH 5-6.5, where the crystalline pp t of N H 4 [UO 2 SaL 3 ] 4 H 2 O has formed. This precipitation has been carried out after concentrating the obtained pregnant leach liquor by its recycle for U extraction from new ore batches. The precipitated ammonium uranyl tri salicylate is calcined at 500 degree C for obtaining pure orange yellow trioxide (UO 3 ) powder. On the basis of one ton ore treatment, an economic flowsheet for U recover y from the study ore material has been suggested

Influence quaternary ammonium salt in the organophilization of an bentonite; Influencia de um sal quaternario de amonio na organofilizacao de uma argila bentonitica

Energy Technology Data Exchange (ETDEWEB)

Oliveira, S.V.; Alves, G.P.; Wanderley, A.S.D.; Araujo, E.M., E-mail: saraveruscadeoliveira@yahoo.com.br [Universidade Federal de Campina Grande (UFCG), Campina Grande, PB (Brazil). Depto de Engenharia de Materiais

2011-07-01

Clays are natural materials, earthy, fine-grained particles with diameters generally less than 2μm, and formed by chemically hydrated silicates of aluminum, iron and magnesium. The clays have a range of applications, both in pottery and in other technology areas. This work aimed to study the influence of a quaternary ammonium salt to increase the basal distance of a bentonite clay powder obtained thereby promoting to a new structural profile characteristic with organoclay. The bentonite clay was treated with salt Praepragem WB. The following methods were used: X-ray diffraction (XRD) and X-ray fluorescence (XRF). The results indicated the intercalation of ammonium ions of the salt studied within the layers of silicate and expansion of basal spacing d{sub 001}, ie the clay in the study showed 2θ angle shifts to smaller angles, indicating that the clay was organophilization. (author)

Magnesium-molybdenum compounds as matrixes of {sup 99m} Tc generators; Compuestos de magnesio-molibdeno como matrices de generadores de {sup 99m} Tc

Energy Technology Data Exchange (ETDEWEB)

Jimenez M, T S

2005-07-01

In order to finding new production alternatives of {sup 99}Mo/ {sup 99m}Tc generators, easy to produce and with high elutriation efficiencies, it is proposed in this work to develop a generator with basis of magnesium and molybdenum that could be irradiated after their synthesis, given the short half life of the only radioisotope produced by the magnesium: {sup 27} Mg (t{sub 1/2} = 9.46 m). It is necessary to mention that have not been reported works in relation to this type of compound, being then important to carry out basic studies on the formation and behavior of these in relation to their matrix functions of those generated of {sup 99} Mo/ {sup 99m} Tc. In this work it was determined the effect that has, the magnesium salt used in the synthesis of those molybdenum-magnesium compounds, the molar ratio Mo: Mg, the concentration of the magnesium salt, the pH of the used ammonium molybdates in the synthesis of the final compounds and the washing of the molybdates of synthesized magnesium, in the performance of the {sup 99} Mo/ {sup 99m} Tc generators. Parameters like the elutriation efficiency, the radionuclide purity, radiochemical and chemical of the eluates and their pH, were determined in each case, also its were characterized the synthesized compounds using: neutron activation analysis (NAA), X-ray diffraction (XRD) and scanning electron microscopy of high vacuum (SEM), besides of complementary techniques: infrared spectroscopy (IR), and thermal gravimetric analysis (TGA). (Author)

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

Science.gov (United States)

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

1986-02-01

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

Combustion and extinction of magnesium fires

International Nuclear Information System (INIS)

Malet, J.C.; Duverger de Cuy, G.

1988-01-01

The studies made in France on magnesium combustion and extinguishing means are associated at the nuclear fuel of the graphite-gas reactor. Safety studies are made for ameliorate our knowledge on: - magnesium combustion - magnesium fire propagation - magnesium fire extinguishing [fr

Magnesium deficiency: What is our status

Science.gov (United States)

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...

Study of hMSC proliferation and differentiation on Mg and Mg–Sr containing biphasic β-tricalcium phosphate and amorphous calcium phosphate ceramics

International Nuclear Information System (INIS)

Singh, Satish S.; Roy, Abhijit; Lee, Boeun; Kumta, Prashant N.

2016-01-01

Biphasic mixtures of either Mg"2"+ or combined Mg"2"+ and Sr"2"+ cation substituted β-tricalcium phosphate (β-TCP) and amorphous calcium phosphate (ACP) were prepared using a low temperature chemical phosphatizing and hydrolysis reaction approach. Scaffolds prepared using the cation substituted calcium phosphates were capable of supporting similar levels of human mesenchymal stem cell proliferation in comparison to commercially available β-TCP. The concentrations of Mg"2"+, Sr"2"+, and PO_4"3"− released from these scaffolds were also within the ranges desired from previous reports to support both hMSC proliferation and osteogenic differentiation. Interestingly, hMSCs cultured directly on scaffolds prepared with only Mg"2"+ substituted β-TCP were capable of supporting statistically significantly increased alkaline phosphatase activity, osteopontin, and osteoprotegerin expression in comparison to all compositions containing both Mg"2"+ and Sr"2"+, and commercially available β-TCP. hMSCs cultured in the presence of scaffold extracts also exhibited similar trends in the expression of osteogenic markers as was observed during direct culture. Therefore, it was concluded that the enhanced differentiation observed was due to the release of bioactive ions rather than the surface microstructure. The role of these ions on transforming growth factor-β and bone morphogenic protein signaling was also evaluated using a PCR array. It was concluded that the release of these ions may support enhanced differentiation through SMAD dependent TGF-β and BMP signaling. - Highlights: • Synthesis of Mg and Mg-Sr containing biphasic beta tricalcium phosphate ceramics • Magnesium substitution influences ALP activity compared to strontium content. • Solution extract plays a more dominant role on hMSC differentiation. • Direct and indirect Mg and Mg-Sr TCP culture show similar OPG and OPN expression.

Study of hMSC proliferation and differentiation on Mg and Mg–Sr containing biphasic β-tricalcium phosphate and amorphous calcium phosphate ceramics

Energy Technology Data Exchange (ETDEWEB)

Singh, Satish S., E-mail: sss42@pitt.edu [Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Roy, Abhijit, E-mail: abr20@pitt.edu [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Lee, Boeun [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Kumta, Prashant N., E-mail: pkumta@pitt.edu [Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Center for Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Department of Mechanical Engineering and Materials Science, University of Pittsburgh, PA 15261 (United States)

2016-07-01

Biphasic mixtures of either Mg{sup 2+} or combined Mg{sup 2+} and Sr{sup 2+} cation substituted β-tricalcium phosphate (β-TCP) and amorphous calcium phosphate (ACP) were prepared using a low temperature chemical phosphatizing and hydrolysis reaction approach. Scaffolds prepared using the cation substituted calcium phosphates were capable of supporting similar levels of human mesenchymal stem cell proliferation in comparison to commercially available β-TCP. The concentrations of Mg{sup 2+}, Sr{sup 2+}, and PO{sub 4}{sup 3−} released from these scaffolds were also within the ranges desired from previous reports to support both hMSC proliferation and osteogenic differentiation. Interestingly, hMSCs cultured directly on scaffolds prepared with only Mg{sup 2+} substituted β-TCP were capable of supporting statistically significantly increased alkaline phosphatase activity, osteopontin, and osteoprotegerin expression in comparison to all compositions containing both Mg{sup 2+} and Sr{sup 2+}, and commercially available β-TCP. hMSCs cultured in the presence of scaffold extracts also exhibited similar trends in the expression of osteogenic markers as was observed during direct culture. Therefore, it was concluded that the enhanced differentiation observed was due to the release of bioactive ions rather than the surface microstructure. The role of these ions on transforming growth factor-β and bone morphogenic protein signaling was also evaluated using a PCR array. It was concluded that the release of these ions may support enhanced differentiation through SMAD dependent TGF-β and BMP signaling. - Highlights: • Synthesis of Mg and Mg-Sr containing biphasic beta tricalcium phosphate ceramics • Magnesium substitution influences ALP activity compared to strontium content. • Solution extract plays a more dominant role on hMSC differentiation. • Direct and indirect Mg and Mg-Sr TCP culture show similar OPG and OPN expression.

Dependence of the phosphate sorption capacity on the aluminium and iron in Finnish soils

Directory of Open Access Journals (Sweden)

Armi Kaila

1963-12-01

Full Text Available An attempt was made to study to what extent the capacity of the more or less acid soils in Finland to sorb phosphate may be explained on the basis of their content of aluminium and iron. The indicator of the phosphate sorption capacity was calculated on the basis of the Freundlich adsorption isotherm according to the procedure proposed by TERÄSVUORI (8. The material consisted of 390 samples from cultivated and virgin soils representing both topsoils and subsoils. The indicator of the phosphate sorption capacity, the coefficient k, varied in the present material from 40 to 1510. The mean values (with the confidence limits at the 95 per cent level were for the 109 samples of sand and fine sand soils 290 ± 17, for the 103 samples of loam and silt soils 201 ± 24, for the 151 clay soils 308 ± 20, and for the 27 humus soils 236 ± 41. The total linear correlation coefficients between k and the soil pH, and its contents of organic carbon or clay were low or negligible in most of the soil groups. The correlation of k with the content of aluminium extracted by Tamm’s acid ammonium oxalate was fairly close in the clay soils (r = 0.84***, lower in the sand and fine sand soils (r = 0.77***, and in the loam and silt soils, and in the humus soils it was rather poor (r = 0.65*** and 0.63*** resp.. The elimination of the effect of the ammonium oxalate soluble iron decreased the correlation in the two latter groups quite markedly (to 0.32** and 0.37 resp., while the corresponding decrease in the coefficients for the former groups was less significant (to 0.64*** and 0.75*** resp.. The elimination of the effect of the ammonium oxalate soluble aluminium, on the other hand, decreased the correlation coefficients between k and the ammonium oxalate soluble iron in the sand and fine sand soils from 0.59*** to 0.26**, in the loam and silt soils from 0.73*** to 0.54***, in the clay soils from 0.70*** to 0.51***, and in the humus soils from 0.68*** to 0.49*. The

Characterization and obtainment of phosphate rock concentrates of Turmequé, Boyacá

Science.gov (United States)

Zanguña, S. Quijano; Lozano Gómez, L. F.; Pineda Triana, Y.

2017-12-01

The work focuses on the use and exploitation of the mineral concentrates from phosphate rock (PR) coming from mines with a low percentage of phosphorus. The procedure was based on the collection of a source of phosphate rock from the department of Boyacá (municipality of Turmequé), using a randomized design with three replications. The samples were initially milled and sifted using meshes between 140 and 200 US standard, homogenizing them and improving the process of solubility of the phosphorus in the soil. We conduced Z-potential tests, which show that by performing a prior wash on the mineral and maintaining certain concentrations and pH defined, better results are achieved in terms of the buoyancy of the particles in the flotation process. The results obtained from the microflotation tests; both direct and inverse, and the results of chemical composition, with X-Ray Fluorescence (XRF) and X-Ray Diffraction (XRD), before and after the microflotation process, were carried out to obtain of commercial laws grade phosphate rock concentrate, confirm that the protocol used increases by 9% the value of total phosphorus in the collected sample. These concentrates from phosphate rock, could be used in the future for the attainment of simple superphosphate (SSP), with the help of sulphuric acid and ammonium thiosulphate mixtures.

Ammonium generation during SRAT cycle

International Nuclear Information System (INIS)

Hsu, C.W.

1992-01-01

During the IDMS noble-metal demonstration runs ammonium nitrate deposition was found in the vessel vent system of the feed preparation area. In the bench-scale experiments of studying the hydrogen generation during the sludge treatment cycle, ammonium ion production was also monitored. It was found that: During a simulation of the DWPF Cold Chemical Runs SRAT cycle no detectable amount of ammonium ions was generated when treating a non-noble-metal containing sludge simulant according to the nitric acid flowsheet. Ammonium ions were generated during the SRAT-SME cycle when treating the noble-metal containing sludge with either formic acid or nitric acid/late-washing PHA. This is due to the reaction between formic acid and nitrate catalyzed by the noble metals in the sludge simulant. Ammonium ion production closely followed the hydrogen evolution from the catalytic decomposition of formic acid. This report summarizes the results of the production of ammonia during the SRAT cycle

A regenerable potassium and phosphate sorbent system to enhance dialysis efficacy and device portability: a study in awake goats.

Science.gov (United States)

Wester, Maarten; Gerritsen, Karin G; Simonis, Frank; Boer, Walther H; Hazenbrink, Diënty H; Vaessen, Koen R; Verhaar, Marianne C; Joles, Jaap A

2017-06-01

Patients on standard intermittent haemodialysis suffer from strong fluctuations in plasma potassium and phosphate. Prolonged dialysis with a wearable device, based on continuous regeneration of a small volume of dialysate using ion exchangers, could moderate these fluctuations and offer increased clearance of these electrolytes. We report in vivo results on the efficacy of potassium and phosphate adsorption from a wearable dialysis device. We explore whether equilibration of ion exchangers at physiological Ca 2+ , Mg 2+ and hypotonic NaCl can prevent calcium/magnesium adsorption and net sodium release, respectively. Effects on pH and HCO3- were studied. Healthy goats were instrumented with a central venous catheter and dialysed. Potassium and phosphate were infused to achieve plasma concentrations commonly observed in dialysis patients. An adsorption cartridge containing 80 g sodium poly(styrene-divinylbenzene) sulphonate and 40 g iron oxide hydroxide beads for potassium and phosphate removal, respectively, was incorporated in a dialysate circuit. Sorbents were equilibrated and regenerated with a solution containing NaCl, CaCl 2 and MgCl 2 . Blood was pumped over a dialyser and dialysate was recirculated over the adsorption cartridge in a countercurrent direction. Potassium and phosphate adsorption was 7.7 ± 2.7 and 4.9 ± 1.3 mmol in 3 h, respectively. Adsorption capacity remained constant during consecutive dialysis sessions and increased with increasing K + and PO43-. Equilibration at physiological Ca 2+ and Mg 2+ prevented net adsorption, eliminating the need for post-cartridge calcium and magnesium infusion. Equilibration at hypotonic NaCl prevented net sodium release Fe 2+ and arterial pH did not change. Bicarbonate was adsorbed, which could be prevented by equilibrating at HCO3- 15 mM. We demonstrate clinically relevant, concentration-dependent, pH-neutral potassium and phosphate removal in vivo with small volumes of regenerable ion exchangers in our

Phosphorus recovery as struvite from eutropic waters by XDA-7 resin.

Science.gov (United States)

Li, Huanwen; Ye, Zhiping; Lin, Ying; Wang, Fengying

2012-01-01

Phosphorus releases into aquatic environment and its subsequent contribution to eutrophication have resulted in a widespread global pollution issue. However, phosphorus is a non-renewable source. The potential supplies of phosphorus are decreasing worldwide. Therefore, removal and recovery of phosphorus from the eutropic waters is important, emergent and necessary. In this research, experiments for recovering phosphate from eutropic waters by anion exchange combined with struvite precipitation were conducted. The results indicated that the prepared XDA-7 resin was an effective adsorbent for phosphate. The adsorption isotherm of XDA-7 resin was found to be a modified Freundlich type. The maximum phosphate adsorption (20.9 mg/g) occurred in the pH range of 6.0-8.0. Phosphate adsorbed on the XDA-7 resin was effectively desorbed with 8% NaCl solution, and the resin was able to be regenerated with 3% NaClO and 4% NaOH solutions. Phosphate desorbed from the resin was recovered as magnesium ammonium phosphate (struvite). The obtained struvite was analyzed by acid dissolution method, scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The struvite precipitate was found to be 75.8% in purity, a high-value fertilizer.

Influence of HEPES buffer on the local pH and formation of surface layer during in vitro degradation tests of magnesium in DMEM

Directory of Open Access Journals (Sweden)

S. Naddaf Dezfuli

2014-10-01

Full Text Available The human body is a buffered environment where pH is effectively maintained. HEPES is a biological buffer often used to mimic the buffering activity of the body in in vitro studies on the degradation behavior of magnesium. However, the influence of HEPES on the degradation behavior of magnesium in the DMEM pseudo-physiological solution has not yet been determined. The research aimed at elucidating the degradation mechanisms of magnesium in DMEM with and without HEPES. The morphologies and compositions of surface layers formed during in vitro degradation tests for 15–3600 s were characterized. The effect of HEPES on the electrochemical behavior and corrosion tendency was determined by performing electrochemical tests. HEPES indeed retained the local pH, leading to intense intergranular/interparticle corrosion of magnesium made from powder and an increased degradation rate. This was attributed to an interconnected network of cracks formed at the original powder particle boundaries and grain boundaries in the surface layer, which provided pathways for the corrosive medium to interact continuously with the internal surfaces and promoted further dissolution. Surface analysis revealed significantly reduced amounts of precipitated calcium phosphates due to the buffering activity of HEPES so that magnesium became less well protected in the buffered environment.

Osteogenic potential of human adipose-derived stromal cells on 3-dimensional mesoporous TiO2 coating with magnesium impregnation

International Nuclear Information System (INIS)

Cecchinato, Francesca; Karlsson, Johan; Ferroni, Letizia; Gardin, Chiara; Galli, Silvia; Wennerberg, Ann; Zavan, Barbara; Andersson, Martin; Jimbo, Ryo

2015-01-01

The aim of this study was to evaluate the osteogenic response of human adipose-derived stromal cells (ADScs) to mesoporous titania (TiO 2 ) coatings produced with evaporation-induced self-assembly method (EISA) and loaded with magnesium. Our emphasis with the magnesium release functionality was to modulate progenitor cell osteogenic differentiation under standard culture conditions. Osteogenic properties of the coatings were assessed for stromal cells by means of scanning electron microscopy (SEM) imaging, colorimetric mitochondrial viability assay (MTT), colorimetric alkaline phosphates activity (ALP) assay and real time RT-polymerase chain reaction (PCR). Using atomic force microscopy (AFM) it was shown that the surface expansion area (S dr ) was strongly enhanced by the presence of magnesium. From MTT results it was shown that ADSc viability was significantly increased on mesoporous surfaces compared to the non-porous one at a longer cell culture time. However, no differences were observed between the magnesium impregnated and non-impregnated surfaces. The alkaline phosphatase activity confirmed that ADSc started to differentiate into the osteogenic phenotype after 2 weeks of culturing. The gene expression profile at 2 weeks of cell growth showed that such coatings were capable to incorporate specific osteogenic markers inside their interconnected nano-pores and, at 3 weeks, ADSc differentiated into osteoblasts. Interestingly, magnesium significantly promoted the osteopontin gene expression, which is an essential gene for the early biomaterial–cell osteogenic interaction. - Highlights: • The magnesium loading presents a transitory effect on mesoporous TiO 2 surface topography • The mesoporous structure promotes cellular attachment and spreading • The mesoporous structure activates osteogenesis of mesenchymal stem cells in absence of osteogenic promoters • The physical adsorbed magnesium is suggested to be involved in the expression of osteopontin

Evidence of ammonium ion-exchange properties of natural bentonite and application to ammonium detection.

Science.gov (United States)

Zazoua, A; Kazane, I; Khedimallah, N; Dernane, C; Errachid, A; Jaffrezic-Renault, N

2013-12-01

Ammonium exchange with hybrid PVC-bentonite (mineral montmorillonite clay) thin film was revealed using FTIR spectroscopy, EDX, cyclic voltammetry and electrochemical impedance spectroscopy. The effect of ammonium exchange on the charge transfer resistance of PVC-bentonite hybrid thin film was attributed to a modification of the intersheet distance and hydration of bentonite crystals. The obtained impedimetric ammonium sensor shows a linear range of detection from 10(-4)M to 1M and a detection limit around 10(-6)M. © 2013.

Spider silk as a template for obtaining magnesium oxide and magnesium hydroxide fibers

Directory of Open Access Journals (Sweden)

Dmitrović Svetlana

2018-01-01

Full Text Available Spider silk fibers, collected from Pholcus Phalangioides spider were used as a template for obtaining magnesium oxide (MgO, periclase as well as magnesium hydroxide (Mg(OH2, brucite fibers. Magnesium oxide fibers were obtained in a simple manner by heat induced decomposition of magnesium salt (MgCl2 in the presence of the spider silk fibers, while magnesium hydroxide fibers were synthesized by hydration of MgO fibers at 50, 70 and 90 C, for 48 and 96 h. According to Scanning electron microscopy (SEM, dimensions of spider silk fibers determined the dimension of synthesized MgO fibers, while for Mg(OH2 fibers, the average diameter was increased with prolonging the hydration period. The surface of Mg(OH2 fibers was noticed to be covered with brucite in a form of plates. X-Ray diffraction (XRD analysis showed that MgO fibers were single-phased (the pure magnesium oxide fibers were obtained, while Mg(OH2 fibers were two- or single-phased brucite depending on incubation period, and/or incubation temperature. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 45012

Magnesium Technology : Preface

NARCIS (Netherlands)

Sillekens, W.H.; Agnew, S.R.; Neelameggham, N.R.; Mathaudhu, S.N.

2011-01-01

The Magnesium Technology Symposium, which takes place every year at the TMS Annual Meeting & Exhibition, is one of the largest yearly gatherings of magnesium specialists in the world. Papers are presented in all aspects of the field, ranging from primary production to applications to recycling.

The Corrosion of Magnesium and of the Magnesium Aluminum Alloys Containing Manganese

Science.gov (United States)

Boyer, J A

1927-01-01

The extensive use of magnesium and its alloys in aircraft has been seriously handicapped by the uncertainties surrounding their resistance to corrosion. This problem has been given intense study by the American Magnesium Corporation and at the request of the Subcommittee on Materials for Aircraft of the National Advisory Committee for Aeronautics this report was prepared on the corrosion of magnesium. The tentative conclusions drawn from the experimental facts of this investigation are as follows: the overvoltage of pure magnesium is quite high. On immersion in salt water the metal corrodes with the liberation of hydrogen until the film of corrosion product lowers the potential to a critical value. When the potential reaches this value it no longer exceeds the theoretical hydrogen potential plus the overvoltage of the metal. Rapid corrosion consequently ceases. When aluminum is added, especially when in large amounts, the overvoltage is decreased and hydrogen plates out at a much lower potential than with pure magnesium. The addition of small amount of manganese raises the overvoltage back to practically that of pure metal, and the film is again negative.

Effect upon biocompatibility and biocorrosion properties of plasma electrolytic oxidation in trisodium phosphate electrolytes.

Science.gov (United States)

Kim, Yu-Kyoung; Park, Il-Song; Lee, Kwang-Bok; Bae, Tae-Sung; Jang, Yong-Seok; Oh, Young-Min; Lee, Min-Ho

2016-03-01

Surface modification to improve the corrosion resistance and biocompatibility of the Mg-Al-Zn-Ca alloy was conducted via plasma electrolytic oxidation (PEO) in an electrolyte that included phosphate. Calcium phosphate can be easily induced on the surface of a PEO coating that includes phosphate in a physiological environment because Ca(2+) ions in body fluids can be combined with PO4 (3-). Cytotoxicity of the PEO coating formed in electrolytes with various amounts of Na3PO4 was identified. In particular, the effects that PEO films have upon oxidative stress and differentiation of osteoblast activity were studied. As the concentration of Na3PO4 in the electrolyte increased, the oxide layer was found to become thicker, which increased corrosion resistance. However, the PEO coating formed in electrolytes with over 0.2 M of added Na3PO4 exhibited more microcracks and larger pores than those formed in smaller Na3PO4 concentrations owing to a large spark discharge. A nonuniform oxide film that included more phosphate caused more cytotoxicity and oxidative stress, and overabundant phosphate content in the oxide layer interrupted the differentiation of osteoblasts. The corrosion resistance of the magnesium alloy and the thickness of the oxide layer were increased by the addition of Na3PO4 in the electrolyte for PEO treatment. However, excessive phosphate content in the oxide layer led to oxidative stress, which resulted in reduced cell viability and activity.

Effects of bottom water dissolved oxygen variability on copper and lead fractionation in the sediments across the oxygen minimum zone, western continental margin of India

Digital Repository Service at National Institute of Oceanography (India)

Chakraborty, P.; Chakraborty, S.; Jayachandran, S.; Madan, R.; Sarkar, Arindam; Linsy, P.; Nath, B.N.

in Table 3. A mixture 5µL of modifier (containing 0.05 mg of ammonium hydrogen phosphate (NH4 H2 PO4) and 0.003 mg of magnesium nitrate (Mg (NO3) 2) was added to 15 µL of sample solution for Pb analysis (http://www.cdc.gov/niosh/docs/2003-154/pdfs/7105...(3-4), 191-237. http://www.cdc.gov/niosh/docs/2003-154/pdfs/7105.pdf Jahnke, R.A., Emerson, S.R. and Murray, J.W., 1982. A model of oxygen reduction, denitrification, and organic matter mineralization in marine sediments1. Limnology and Oceanography, 27...

Plant-wide modelling of phosphorus transformations in wastewater treatment systems: Impacts of control and operational strategies

DEFF Research Database (Denmark)

Solon, Kimberly; Flores Alsina, Xavier; Kazadi Mbamba, C

2017-01-01

of an ammonium (SNHX ) and total suspended solids (XTSS) control strategy (A1) better adapts the system to influent dynamics, improves phosphate (SPO4) accumulation by phosphorus accumulating organisms (XPAO) (41%), increases nitrification/denitrification efficiency (18%) and reduces aeration energy (Eaeration...... unit (A3) for P recovery reduces the quantity of P in the anaerobic digester supernatant returning to the water line and allows potential struvite ( XMgNH4PO4 ) recovery ranging from 69 to 227 kg.day-1 depending on: (1) airflow (Qstripping); and, (2) magnesium (QMg(OH)2 ) addition. All the proposed...

Photoluminescence of magnesium-associated color centers in LiF crystals implanted with magnesium ions

Science.gov (United States)

Nebogin, S. A.; Ivanov, N. A.; Bryukvina, L. I.; V. Shipitsin, N.; E. Rzhechitskii, A.; Papernyi, V. L.

2018-05-01

In the present paper, the effect of magnesium nanoparticles implanted in a LiF crystal on the optical properties of color centers is studied. The transmittance spectra and AFM images demonstrate effective formation of the color centers and magnesium nanoparticles in an implanted layer of ∼ 60-100 nm in thickness. Under thermal annealing, a periodical structure is formed on the surface of the crystal and in the implanted layer due to self-organization of the magnesium nanoparticles. Upon excitation by argon laser with a wavelength of 488 nm at 5 K, in a LiF crystal, implanted with magnesium ions as well as in heavily γ-irradiated LiF: Mg crystals, luminescence of the color centers at λmax = 640 nm with a zero-phonon line at 601.5 nm is observed. The interaction of magnesium nanoparticles and luminescing color centers in a layer implanted with magnesium ions has been revealed. It is shown that the luminescence intensity of the implanted layer at a wavelength of 640 nm is by more than two thousand times higher than that of a heavily γ-irradiated LiF: Mg crystal. The broadening of the zero-phonon line at 601.5 nm in the spectrum of the implanted layer indicates the interaction of the emitting quantum system with local field of the surface plasmons of magnesium nanoparticles. The focus of this work is to further optimize the processing parameters in a way to result in luminescence great enhancement of color centers by magnesium nanoparticles in LiF.

Comprehensive thermal and structural characterization of antimony-phosphate glass

Science.gov (United States)

Moustafa, S. Y.; Sahar, M. R.; Ghoshal, S. K.

For the first time, we prepare new ternary glass systems of composition (95-x)Sb2O3-xP2O5-5MgO, where x = 45, 40, 35 mol%; (85-x)Sb2O3-xP2O5-15MgO, where x = 55, 35, 25 mol%; (75-x)Sb2O3-xP2O5-25MgO, where x = 45, 35, 25 mol%; and 60Sb2O3-(40-x)P2O5-xMgO, where x = 10, 20 mol% via melt-quenching method. Synthesized glasses are characterized using XRD, FESEM, EDX, and TG/DTA measurements. The influence of varying modifier concentrations on their thermal properties is evaluated. The XRD patterns confirmed the amorphous nature of samples. SEM images demonstrated interesting phase formation with ribbons-like texture. Five crystalline phases are evidenced in the ternary diagram which are antimony phosphate and antimony orthophosphate as major phases as well as magnesium phosphate, magnesium cyclo-tetraphosphate and cervantite as minor phases. EDX spectra detected the right elemental traces. Detailed thermal analysis of these glasses revealed their high-molecular polymer character for Sb2O3 content greater than 50 mol%. Three different glass transition temperatures are achieved around 276, 380-381 and 422-470 °C depending on the composition. Furthermore, the solidus and liquidus temperature are found to decrease with increasing Sb2O3 and increases for MgO contents till 15 mol% and then decrease, where the lowest recorded solidus temperature is 426 °C. This observation may open up new research avenues for antimony based ternary glasses and an exploitation of the derived results for optoelectronics applications, photonic devices and non-linear optical devices.

Fabrication of a Biomass-Based Hydrous Zirconium Oxide Nanocomposite for Preferable Phosphate Removal and Recovery.

Science.gov (United States)

Qiu, Hui; Liang, Chen; Zhang, Xiaolin; Chen, Mindong; Zhao, Yunxia; Tao, Tao; Xu, Zhengwen; Liu, Gang

2015-09-23

Advanced removal of phosphate by low-cost adsorbents from municipal wastewater or industrial effluents is an effective and economic way to prevent the occurrence of eutrophication. Here, we proposed a novel method to immobilize hydrous zirconium oxide nanoparticle within quaternary-aminated wheat straw, and obtained an inexpensive, eco-friendly nanocomposite Ws-N-Zr. The biomass-based Ws-N-Zr exhibited higher preference toward phosphate than commercial anion exchanger IRA-900 when competing sulfate ions coexisted at relatively high levels. Such excellent performance of Ws-N-Zr resulted from its specific hybrid structure, the quaternary ammonium groups bonded on the host favor the preconcentration of phosphate ions inside the wheat straw based on Donnan effect, and the encapsulated HZO nanoparticle exhibits preferable sequestration of phosphate ions through specific interaction, as further demonstrated by FTIR and X-ray photoelectron spectroscopy. Cycle adsorption and regeneration experiments demonstrated that Ws-N-Zr could be employed for repeated use without significant capacity loss, when the binary NaOH-NaCl solution was employed as the regenerant. The influence of solution pH and contact time was also examined. The results suggested that Ws-N-Zr has a great potential in efficient removal of phosphate in contaminated waters.

Utilization of struvite recovered from high-strength ammonium-containing simulated wastewater as slow-release fertilizer and fire-retardant barrier.

Science.gov (United States)

Yetilmezsoy, Kaan; Kocak, Emel; Akbin, Havva Melda; Özçimen, Didem

2018-06-28

Sustainable uses of the struvite (magnesium ammonium phosphate hexahydrate, MgNH 4 PO 4 ·6H 2 O, MAP) recovered from the synthetic wastewater, as a high-quality slow-release fertilizer for the growth of nine medicinal plants and a fire-retardant barrier on the flammability of cotton fabric and wooden plate, were explored in this study. The previous experimental results demonstrated that under the optimal conditions, about 98.7% of [Formula: see text] (initial [Formula: see text] = 1000 mg/L) could be effectively and successfully recovered from simulated wastewater in the form of MAP precipitate. Rates of increase in total fresh weights, total dry weights, and fresh heights of plants grown in soil fertilized with the struvite were determined as 67%, 52%, and 12% for valerian; 121%, 75%, and 18% for cucumber; 421%, 260%, and 47% for dill; 314%, 318%, and 27% for coriander; 432%, 566%, and 30% for tomato; 285%, 683%, and 26% for parsley; 200%, 225%, and 9% for basil; 857%, 656%, and 92% for rocket; and 146%, 115%, and 28% for cress, respectively, compared to the control pots. The microstructure, elemental composition, surface area, thermal behaviour, and functional groups of the grown crystals were characterized using SEM, EDS, BET, TGA-DTG-DSC, and FTIR analyses, respectively. Flammability tests and thermal analyses concluded that the dried and crumbled/implanted form of struvite used as a fire-retardant barrier demonstrated a remarkable flame-resistant behaviour for both cotton fabric and wooden plate. Findings of this experimental study clearly corroborated the versatility of struvite as non-polluting and environmentally friendly clean product for the sustainable usage in different fields.

Glufosinate ammonium selection of transformed Arabidopsis.

Science.gov (United States)

Weigel, Detlef; Glazebrook, Jane

2006-12-01

INTRODUCTIONOne of the most commonly used markers for the selection of transgenic Arabidopsis is resistance to glufosinate ammonium, an herbicide that is sold under a variety of trade names including Basta and Finale. Resistance to glufosinate ammonium is conferred by the bacterial bialophos resistance gene (BAR) encoding the enzyme phosphinotricin acetyl transferase (PAT). This protocol describes the use of glufosinate ammonium to select transformed Arabidopsis plants. The major advantage of glufosinate ammonium selection is that it can be performed on plants growing in soil and does not require the use of sterile techniques.

Magnesium oxychloride cement concrete

Indian Academy of Sciences (India)

TECS

exposure to water and salt attack by replacing 10% magnesium chloride solution by magnesium sulphate solution ... Having tremendous load bearing capacity, it can withstand .... retention coefficients for similar concrete compositions.

21 CFR 184.1443 - Magnesium sulfate.

Science.gov (United States)

2010-04-01

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

Mineral resource of the month: magnesium

Science.gov (United States)

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).

21 CFR 184.1431 - Magnesium oxide.

Science.gov (United States)

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 carbonate...

21 CFR 184.1426 - Magnesium chloride.

Science.gov (United States)

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... hydrochloric acid solution and crystallizing out magnesium chloride hexahydrate. (b) The ingredient meets the...

Effect of heavy store dressing with rock phosphate on a fine sand soil

Directory of Open Access Journals (Sweden)

Armi Kaila

1969-05-01

Full Text Available Results are reported of a long-term field trial on acid fine sand soil in which the effects of store dressing with rock phosphate in amounts of 0, 4000, 8000, or 12000 kg/ha was studied comparing them with an annual application of 200 kg/ha of superphosphate using the split plot technique. In the first four years, more thoroughly studied, the response to the store dressing with rock phosphate was distinct both in the dry matter yields and the phosphorus content of the cereal and the red clover-timothy hay. The differences between the various rates of rock phosphate treatments were not statistically significant, though there was some tendency to higher results with larger amounts of rock phosphate. The annual applications of superphosphate as surface dressing to the ley did not brought about any significant increase in the dry matter yield of the rock phosphate plots, and although they tended to increase the phosphorus content of hay, the increase was statistically significant only in a few cases. No effect was found on the phosphorus content of barley grain and straw in the ninth experimental year. No differences were found in the calcium, magnesium, or potassium content of the plant samples from the variously treated plots. Nitrogen content of clover and timothy was increased by both rock phosphate and superphosphate, particularly in the first year ley. In this soil, 4000 kg/ha of rock phosphate was effective enough to produce higher dry matter yields of hay, with equal phosphorus content, than the annual application of 200 kg/ha of superphosphate. Soil analyses indicated that this soil represented the extreme pattern of phosphorus retention in which applied phosphate is almost completely retained as aluminium bound forms of the fluoride soluble fraction supposed to be fairly available. It was suggested that in soils which retain the slowly dissolving rock phosphate phosphorus mainly as less available iron bound forms, heavy applications of

Reaction between CO2 and phosphate to form carboxyphosphate?

International Nuclear Information System (INIS)

Knight, W.B.; Attwood, P.V.; Cleland, W.W.

1986-01-01

Carboxyphosphate (I) is thought to be an intermediate in the enzymic carboxylation of biotin by bicarbonate and MgATP, and a plausible mechanism of carboxyl transfer to the enolate of biotin involves decarboxylation to CO 2 and phosphate. Such a process would have to be reversible, however, as carboxylase reactions are reversible. To test this possibility, the authors undertook the synthesis of I under anhydrous conditions with a high mole fraction of CO 2 present. CO 2 was distilled into capillary tubes under vacuum containing dry tris-(tetrabutyl-ammonium)-phosphate in dimethylformamide. The tubes were sealed and warmed to -10 or 20 0 C and examined by 31 P NMR. Two resonances (1.7 ppm and -5.0 ppm) in addition to phosphate (3.3 ppm) were observed. The relative ratio of each peak to the phosphate one was dependent on the temperature and the concentrations of PO 4 3- and CO 2 . Upon freezing the tubes, cracking them, and release of the CO 2 , the two additional species decomposed slowly to PO 4 3- , and more rapidly to HPO 4 3- upon the addition of H 2 O. Under some conditions they observed an additional resonance (-7.0 ppm) which is most likely pyrophosphate (PP/sub i/). At high concentrations of PO 4 3- and CO 2 , PP/sub i/ was produced and precipitated from solution. The production of PP/sub i/ is most easily explained by attack of PO 4 3- on I. They are currently trying to identify the unknown species observed in the 31 P NMR spectra

Osteogenic potential of human adipose-derived stromal cells on 3-dimensional mesoporous TiO{sub 2} coating with magnesium impregnation

Energy Technology Data Exchange (ETDEWEB)

Cecchinato, Francesca, E-mail: francesca.cecchinato@mah.se [Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö (Sweden); Karlsson, Johan [Department of Chemical and Biological Engineering, Applied Surface Chemistry, Chalmers University of Technology, Gothenburg (Sweden); Ferroni, Letizia; Gardin, Chiara [Department of Histology, Microbiology, and Medical Biotechnologies, University of Padova, Padova (Italy); Galli, Silvia; Wennerberg, Ann [Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö (Sweden); Zavan, Barbara [Department of Histology, Microbiology, and Medical Biotechnologies, University of Padova, Padova (Italy); Andersson, Martin [Department of Chemical and Biological Engineering, Applied Surface Chemistry, Chalmers University of Technology, Gothenburg (Sweden); Jimbo, Ryo [Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö (Sweden); Department of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki (Japan)

2015-07-01

The aim of this study was to evaluate the osteogenic response of human adipose-derived stromal cells (ADScs) to mesoporous titania (TiO{sub 2}) coatings produced with evaporation-induced self-assembly method (EISA) and loaded with magnesium. Our emphasis with the magnesium release functionality was to modulate progenitor cell osteogenic differentiation under standard culture conditions. Osteogenic properties of the coatings were assessed for stromal cells by means of scanning electron microscopy (SEM) imaging, colorimetric mitochondrial viability assay (MTT), colorimetric alkaline phosphates activity (ALP) assay and real time RT-polymerase chain reaction (PCR). Using atomic force microscopy (AFM) it was shown that the surface expansion area (S{sub dr}) was strongly enhanced by the presence of magnesium. From MTT results it was shown that ADSc viability was significantly increased on mesoporous surfaces compared to the non-porous one at a longer cell culture time. However, no differences were observed between the magnesium impregnated and non-impregnated surfaces. The alkaline phosphatase activity confirmed that ADSc started to differentiate into the osteogenic phenotype after 2 weeks of culturing. The gene expression profile at 2 weeks of cell growth showed that such coatings were capable to incorporate specific osteogenic markers inside their interconnected nano-pores and, at 3 weeks, ADSc differentiated into osteoblasts. Interestingly, magnesium significantly promoted the osteopontin gene expression, which is an essential gene for the early biomaterial–cell osteogenic interaction. - Highlights: • The magnesium loading presents a transitory effect on mesoporous TiO{sub 2} surface topography • The mesoporous structure promotes cellular attachment and spreading • The mesoporous structure activates osteogenesis of mesenchymal stem cells in absence of osteogenic promoters • The physical adsorbed magnesium is suggested to be involved in the expression of

Determination of phosphorus fertilizer soil reactions by Raman and synchrotron infrared microspectroscopy.

Science.gov (United States)

Vogel, Christian; Adam, Christian; Sekine, Ryo; Schiller, Tara; Lipiec, Ewelina; McNaughton, Don

2013-10-01

The reaction mechanisms of phosphate-bearing mineral phases from sewage sludge ash-based fertilizers in soil were determined by Raman and synchrotron infrared microspectroscopy. Different reaction mechanisms in wet soil were found for calcium and magnesium (pyro-) phosphates. Calcium orthophosphates were converted over time to hydroxyapatite. Conversely, different magnesium phosphates were transformed to trimagnesium phosphate. Since the magnesium phosphates are unable to form an apatite structure, the plant-available phosphorus remains in the soil, leading to better growth results observed in agricultural pot experiments. The pyrophosphates also reacted very differently. Calcium pyrophosphate is unreactive in soil. In contrast, magnesium pyrophosphate quickly formed plant-available dimagnesium phosphate.

Prognostic importance of plasma total magnesium in a cohort of cats with azotemic chronic kidney disease.

Science.gov (United States)

van den Broek, D Hendrik N; Chang, Yu-Mei; Elliott, Jonathan; Jepson, Rosanne E

2018-04-27

Hypomagnesemia is associated with increased mortality and renal function decline in humans with chronic kidney disease (CKD). Magnesium is furthermore inversely associated with fibroblast growth factor 23 (FGF23), an important prognostic factor in CKD in cats. However, the prognostic significance of plasma magnesium in cats with CKD is unknown. To explore associations of plasma total magnesium concentration (tMg) with plasma FGF23 concentration, all-cause mortality, and disease progression in cats with azotemic CKD. Records of 174 client-owned cats with IRIS stage 2-4 CKD. Cohort study. Cats with azotemic CKD were identified from the records of two London-based first opinion practices (1999-2013). Possible associations of baseline plasma tMg with FGF23 concentration and risks of death and progression were explored using, respectively, linear, Cox, and logistic regression. Plasma tMg (reference interval, 1.73-2.57 mg/dL) was inversely associated with plasma FGF23 when controlling for plasma creatinine and phosphate concentrations (partial correlation coefficient, -0.50; P tMg augments prognostic information in cats with CKD, but whether these observations are associations or causations warrants further investigation. © 2018 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Lightweight Heat Pipes Made from Magnesium

Science.gov (United States)

Rosenfeld, John N.; Zarembo, Sergei N.; Eastman, G. Yale

2010-01-01

Magnesium has shown promise as a lighter-weight alternative to the aluminum alloys now used to make the main structural components of axially grooved heat pipes that contain ammonia as the working fluid. Magnesium heat-pipe structures can be fabricated by conventional processes that include extrusion, machining, welding, and bending. The thermal performances of magnesium heat pipes are the same as those of equal-sized aluminum heat pipes. However, by virtue of the lower mass density of magnesium, the magnesium heat pipes weigh 35 percent less. Conceived for use aboard spacecraft, magnesium heat pipes could also be attractive as heat-transfer devices in terrestrial applications in which minimization of weight is sought: examples include radio-communication equipment and laptop computers.

Electrocrystallization, growth and characterization of calcium phosphate ceramics on magnesium alloys

International Nuclear Information System (INIS)

Grubač, Z.; Metikoš-Huković, M.; Babić, R.

2013-01-01

Highlights: • HA coating preparation on Mg-alloy includes electrochemical and chemical processes. • Two step coating formation is a convenient method for bone-like coating formation. • Electrochemically assisted deposition enables to coat implants with a complex shape. • Electrocrystallization of CaHPO 4 film occurs as 3D instantaneous nucleation. • Bioactive properties of HA coatings were directly identified with Ca/P mole ratio. -- Abstract: In order to make biodegradable magnesium alloys corrosion resistant for a potential orthopaedic and bio-implant application, their surface should be modified with bioactive bone-like hydroxyapatite (HA) coatings. In the present paper, the initial step of coating formation on Mg alloy was studied by electrochemical techniques. The electrocrystallization and growth of the surface film occur as an instantaneous 3D nucleation under diffusion control, as was extracted from a fitting procedure of current-time transient data to the various nucleation models. Electrodeposited calcium hydrogenphosphate coatings were converted into bone-like HA (calcium deficient HA) in an alkaline treatment. The bioactive properties of HA coatings have been directly identified with a Ca/P mole ratio. Their morphology, composition and barrier properties were identified using scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS), and voltammetry

21 CFR 862.1495 - Magnesium test system.

Science.gov (United States)

2010-04-01

... magnesium levels in serum and plasma. Magnesium measurements are used in the diagnosis and treatment of hypomagnesemia (abnormally low plasma levels of magnesium) and hypermagnesemia (abnormally high plasma levels of magnesium). (b) Classification. Class I. ...

Radioactive 210Po in magnesium supplements

International Nuclear Information System (INIS)

Struminska-Parulska, Dagmara Ida

2016-01-01

The aim of this pioneer study was to determine polonium 210 Po in the most popular magnesium supplements in Poland and estimate the possible related dose assessment to the consumers. The analyzed magnesium pharmaceutics contained organic or inorganic magnesium compounds; some from natural sources. The objectives of this research were to investigate the naturally occurring 210 Po activity concentrations in magnesium supplements, find the correlations between 210 Po concentration in medicament and magnesium chemical form, and calculate the effective radiation dose connected to analyzed magnesium supplement consumption. The highest 210 Po activity concentrations were determined in mineral tablets made from sedimentary rocks, namely dolomite - 3.84 ± 0.15 mBq g -1 (sample Mg17). The highest annual radiation dose from 210 Po taken with 1 tablet of magnesium supplement per day or with 400 mg of pure Mg daily would come from sample Mg17 (dolomite) - 1.35 ± 0.5 and 8.44 ± 0.33 μSv year -1 respectively.

Study of monosubstituted phosphate dihydrates of magnesium, manganese and cadmium

International Nuclear Information System (INIS)

Dzyuba, E.D.; Pechkovskij, V.V.; Salonets, G.I.; Kovalishina, V.I.; Ivkovich, N.A.; Chubarov, A.V.

1982-01-01

Thermal stability and structural transformations while heating dihydrates of monosubstituted phosphates of the composition M(H 2 PO 4 ) 2 x2H 2 O (where M=Mg, Mn, Cd) have been studied. It is shown that on the whole the character of dehydration of the above crystallohydrates is very much alike, but the chemism and composition of the products at intermediate stages of dehydration is somewhat different. Complication of dehydration chemism of Mn(H 2 PO 4 ) 2 x2H 2 O and Cd(H 2 PO 4 ) 2 x2H 2 O (separation of free phosphoric acid, formation of polyphosphates with polymerization degree n=4-6) can be conditioned by a higher degree of interaction of 3d-orbitals of manganese and cadmium with H 2 -PO 4 -anion. Evaluation of activation energies of the first dehydration stage of Mn(H 2 PO 4 ) 2 x2H 2 O and Cd(H 2 PO 4 ) 2 x2H 2 O is carried out. Values of activation energies constituted approximately 71 and 77.5 kJ/mol respectively

Alkoxide-based magnesium electrolyte compositions for magnesium batteries

Science.gov (United States)

Dai, Sheng; Sun, Xiao-Guang; Liao, Chen; Guo, Bingkun

2018-01-30

Alkoxide magnesium halide compounds having the formula: RO--Mg--X (1) wherein R is a saturated or unsaturated hydrocarbon group that is unsubstituted, or alternatively, substituted with one or more heteroatom linkers and/or one or more heteroatom-containing groups comprising at least one heteroatom selected from fluorine, nitrogen, oxygen, sulfur, and silicon; and X is a halide atom. Also described are electrolyte compositions containing a compound of Formula (1) in a suitable polar aprotic or ionic solvent, as well as magnesium batteries in which such electrolytes are incorporated.

Ph effect on tricalcium phosphate (Ca3(PO4)2) thermoluminescence

International Nuclear Information System (INIS)

Barrera V, A.; Zarate M, J.; Lemus R, J.; Sanchez, A.; Rivera M, T.

2015-10-01

The study of the ph effect is presented on thermoluminescent response of calcium phosphates synthesized by precipitation process. For the synthesis by precipitation, were used: calcium nitrate (Ca(NO 3 ) 2 and ammonium phosphate dibasic ((NH 4 ) 2 HPO 4 ) as precursors. Samples were obtained at ph 7, 8, 9 and 10 and subjected to a calcination s temperature of 1100 C. Samples were also irradiated with X rays of 6 MV to a dose of 2 Gy. Samples prior to irradiation showed no luminescence, the irradiated samples displayed a luminescent curve which is due to the X-ray response. Powders synthesized at ph 7 showed a well-defined peak centered at 267 grades C. The rest of the prepared samples showed a luminescent curve composed of several peaks. By analyzing the curve at ph 7 by the method of the shape of the curve, was found to have an order of 1.7, with an activation energy, E = 1.44 ± 0.04 eV. (Author)

Nanostructured magnesium increases bone cell density.

Science.gov (United States)

Weng, Lucy; Webster, Thomas J

2012-12-07

Magnesium has attracted some attention in orthopedics due to its biodegradability and mechanical properties. Since magnesium is an essential natural mineral for bone growth, it can be expected that as a biomaterial, it would support bone formation. However, upon degradation in the body, magnesium releases OH(-) which results in an alkaline pH that can be detrimental to cell density (for example, osteoblasts or bone forming cells). For this reason, modification of magnesium may be necessary to compensate for such detrimental effects to cells. This study created biologically inspired nanoscale surface features on magnesium by soaking magnesium in various concentrations of NaOH (from 1 to 10 N) and for various periods of time (from 10 to 30 min). The results provided the first evidence of increased roughness, surface energy, and consequently greater osteoblast adhesion, after 4 h as well as density up to 7 days on magnesium treated with any concentration of NaOH for any length of time compared to untreated controls. For these reasons, this study suggests that soaking magnesium in NaOH could be an inexpensive, simple and effective manner to promote osteoblast functions for numerous orthopedic applications and, thus, should be further studied.

Calcium and magnesium determination

International Nuclear Information System (INIS)

Bhattacharya, S.K.

1982-01-01

The roles of calcium and magnesium in human health and disease have been extensively studied. Calcium and magnesium have been determined in biological specimens by atomic absorption spectroscopy using stiochiometric nitrous oxide-acetylene flame

Recent progress in fission product separation; Progres recents de la separation des produits de fission

Energy Technology Data Exchange (ETDEWEB)

Raggenbass, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

Successful experiments have been done on the method described at Geneva in 1958. The process has been considerably improved: 1 - Initially, the caesium phospho tungstate precipitate was leached barium hydroxide in the centrifuge and this was followed by a distillation of ammonia in a concentrator. The barium hydroxide was then eliminated by carbonate precipitation and centrifugation. It has been proved that the ammonia distillation could be replaced by its evaporation during centrifugation, thus eliminating the need of a concentrator. It was then possible to carry out the carbonation on the solide-liquid mixture produced by the baryte water leaching. 2 - In applying the above process to the treatment of solutions derived from uranium molybdenum fuels, concentrating is to be recommended in order to hold the molybdenum in solution by complexing it with phosphoric acid. This complexing process provides a suspension of zirconium phosphate and ammonium phospho tungstate. These are separated by passing into a basic medium which precipitates the zirconium oxide, then turning back to an acid medium; the end of the treatment remains unchanged. 3 - Studies carried out in several countries on the exchange properties of hetero-polyacid salts have always met with difficulties as a result of the poor mechanical properties of these substances. This difficulty has been overcome by wrapping the ammonium phospho tungstate in a zirconium phosphate matrix. The exchanger obtained possesses: satisfactory mechanical properties, - a capacity of 0.1 milli equivalent per gram in concentrated nitric acid solution. It can be eluted and regenerated by a solution of an ammonium salt. The procedure for recovery of these various fission products is briefly the following: extraction of rare earths by di-2-ethyl hexyl phosphoric acid into dodecane at pH 2, the chemical impurities being complexed by citric acid, extraction of most of the magnesium at pH 4 by the same solvents the solvent being

A SEARCH FOR MAGNESIUM IN EUROPA'S ATMOSPHERE

International Nuclear Information System (INIS)

Hörst, S. M.; Brown, M. E.

2013-01-01

Europa's tenuous atmosphere results from sputtering of the surface. The trace element composition of its atmosphere is therefore related to the composition of Europa's surface. Magnesium salts are often invoked to explain Galileo Near Infrared Mapping Spectrometer spectra of Europa's surface, thus magnesium may be present in Europa's atmosphere. We have searched for magnesium emission in the Hubble Space Telescope Faint Object Spectrograph archival spectra of Europa's atmosphere. Magnesium was not detected and we calculate an upper limit on the magnesium column abundance. This upper limit indicates that either Europa's surface is depleted in magnesium relative to sodium and potassium, or magnesium is not sputtered as efficiently resulting in a relative depletion in its atmosphere.

Corrosion of magnesium and some magnesium alloys in gas cooled reactors

International Nuclear Information System (INIS)

Caillat, R.; Darras, R.

1958-01-01

The results of corrosion tests on magnesium and some magnesium alloys (Mg-Zr and Mg-Zr-Zn) in moist air (like G1 reactor) and in CO 2 : (like G2, G3, EDF1 reactors) are reported. The maximum temperature for exposure of magnesium to moist air without any risk of corrosion is 350 deg. C. Indeed, the oxidation rate follows a linear law above 350 deg. C although it reaches a constant level and keeps on very low under 350 deg. C. However, as far as corrosion is concerned this temperature limit can be raised up to 500 deg. C if moist air is very slightly charged with fluorinated compounds. Under pressure of CO 2 , these three materials oxidate much more slowly even if 500 deg. C is reached. The higher is the temperature, the higher is the constant level of the weight increase and the quicker is reached this one. However, Mg-Zr alloy behaves quite better than pure magnesium and especially than Mg-Zr-Zn alloy. (author) [fr

Phosphate binders for the treatment of hyperphosphatemia in chronic kidney disease patients on dialysis: a comparison of safety profiles.

Science.gov (United States)

Locatelli, Francesco; Del Vecchio, Lucia; Violo, Leano; Pontoriero, Giuseppe

2014-05-01

Hyperphosphatemia is common in the late stages of chronic kidney disease (CKD) and is associated with elevated parathormone levels, abnormal bone mineralization, extraosseous calcification and increased risk of cardiovascular events and death. Several classes of oral phosphate binders are available to help control phosphorus levels. Although effective at lowering serum phosphorus, they all have safety issues that need to be considered when selecting which one to use. This paper reviews the use of phosphate binders in patients with CKD on dialysis, with a focus on safety and tolerability. In addition to the more established agents, a new resin-based phosphate binder, colestilan, is discussed. Optimal phosphate control is still an unmet need in CKD. Nonetheless, we now have an extending range of phosphate binders available. Aluminium has potentially serious toxic risks. Calcium-based binders are still very useful but can lead to hypercalcemia and/or positive calcium balance and cardiovascular calcification. No long-term data are available for the new calcium acetate/magnesium combination product. Lanthanum is an effective phosphate binder, but there is insufficient evidence about possible long-term effects of tissue deposition. The resin-based binders, colestilan and sevelamer, appear to have profiles that would lead to less vascular calcification, and the main adverse events seen with these agents are gastrointestinal effects.

21 CFR 175.105 - Adhesives.

Science.gov (United States)

2010-04-01

.... Ammonium borate Ammonium citrate Ammonium persulfate Ammonium polyacrylate Ammonium potassium hydrogen... Chromium potassium sulfate Cobaltous acetate Coconut fatty acid amine salt of tetrachlorophenol For use as... of such acids, single or mixed, as follows: Aluminum Ammonium Calcium Magnesium Potassium Sodium Zinc...

Novel routes in flame retardancy of bisphenol A polycarbonate/impact modifier/aryl phosphate blends

Energy Technology Data Exchange (ETDEWEB)

Wawrzyn, Eliza

2013-07-01

The massive use of electronic engineering products accompanied by high demands on fire safety has led to increasing interest in environmentally friendly flame retardancy of bisphenol A polycarbonate (PC) based materials. In this work, novel routes for enhancing the flame retardancy of PC/Impact Modifier/Aryl phosphate were studied with respect to pyrolysis (TG, TG-FTIR, ATR-FTIR, NMR), flammability (LOI and UL 94) and fire behavior (cone calorimeter at different irradiations). To improve charring of PC/ABS{sub PTFE}+Aryl phosphate, the exchange of bisphenol A bis(diphenyl phosphate) (BDP) with novel aryl phosphates was proposed. Two novel flame retardants were synthesized: 3,3,5-trimethylcyclohexylbisphenol-bis(diphenyl phosphate) (TMC-BDP) and bisphenol A-bis(diethylphosphate) (BEP). TMC-BDP was more stable than BDP, thus gave a potential to increase the chemical reactions between the components of the PC/ABS{sub PTFE}+Aryl phosphate, whereas more reactive BEP was expected to increase the cross linking activity with the polymer matrix. Nevertheless, the corresponding blends did not enhance the flame retardancy compared to PC/ABS{sub PTFE}+BDP. BEP in PC/ABS{sub PTFE} preferred to cross-link with itself instead of with PC, thus it showed poor fire protection performance. TMC-BDP gave as good results as BDP in PC/ABS PTFE material. The results delivered evidence that BDP possesses a high degree of optimization in PC/ABS{sub PTFE} system. To provide a novel impact modifier improving not only mechanical properties but also the fire retardancy of PC/BDP material, the replacement of highly flammable acrylonitrile-butadiene-styrene (ABS) with silicon acrylate rubber (SiR) with high content of polydimethylsiloxane (PDMS) was studied. In PC/SiR{sub PTFE}/BDP the replacement of ABS is beneficial, but PDMS worsened the BDP gas phase and condensed phase action. PDMS reacted also with PC during combustion. PDMS-PC and PDMS-BDP interactions led to silicon dioxide. In fact, the

Electrothermal atomic absorption spectrometric determination of copper in nickel-base alloys with various chemical modifiers*1

Science.gov (United States)

Tsai, Suh-Jen Jane; Shiue, Chia-Chann; Chang, Shiow-Ing

1997-07-01

The analytical characteristics of copper in nickel-base alloys have been investigated with electrothermal atomic absorption spectrometry. Deuterium background correction was employed. The effects of various chemical modifiers on the analysis of copper were investigated. Organic modifiers which included 2-(5-bromo-2-pyridylazo)-5-(diethylamino-phenol) (Br-PADAP), ammonium citrate, 1-(2-pyridylazo)-naphthol, 4-(2-pyridylazo)resorcinol, ethylenediaminetetraacetic acid and Triton X-100 were studied. Inorganic modifiers palladium nitrate, magnesium nitrate, aluminum chloride, ammonium dihydrogen phosphate, hydrogen peroxide and potassium nitrate were also applied in this work. In addition, zirconium hydroxide and ammonium hydroxide precipitation methods have also been studied. Interference effects were effectively reduced with Br-PADAP modifier. Aqueous standards were used to construct the calibration curves. The detection limit was 1.9 pg. Standard reference materials of nickel-base alloys were used to evaluate the accuracy of the proposed method. The copper contents determined with the proposed method agreed closely with the certified values of the reference materials. The recoveries were within the range 90-100% with relative standard deviation of less than 10%. Good precision was obtained.

Nanostructured magnesium increases bone cell density

International Nuclear Information System (INIS)

Weng, Lucy; Webster, Thomas J

2012-01-01

Magnesium has attracted some attention in orthopedics due to its biodegradability and mechanical properties. Since magnesium is an essential natural mineral for bone growth, it can be expected that as a biomaterial, it would support bone formation. However, upon degradation in the body, magnesium releases OH − which results in an alkaline pH that can be detrimental to cell density (for example, osteoblasts or bone forming cells). For this reason, modification of magnesium may be necessary to compensate for such detrimental effects to cells. This study created biologically inspired nanoscale surface features on magnesium by soaking magnesium in various concentrations of NaOH (from 1 to 10 N) and for various periods of time (from 10 to 30 min). The results provided the first evidence of increased roughness, surface energy, and consequently greater osteoblast adhesion, after 4 h as well as density up to 7 days on magnesium treated with any concentration of NaOH for any length of time compared to untreated controls. For these reasons, this study suggests that soaking magnesium in NaOH could be an inexpensive, simple and effective manner to promote osteoblast functions for numerous orthopedic applications and, thus, should be further studied. (paper)

Composition of highly concentrated silicate electrolytes and ultrasound influencing the plasma electrolytic oxidation of magnesium

Science.gov (United States)

Simchen, F.; Rymer, L.-M.; Sieber, M.; Lampke, T.

2017-03-01

Magnesium and its alloys are increasingly in use as lightweight construction materials. However, their inappropriate corrosion and wear resistance often prevent their direct practical use. The plasma electrolytic oxidation (PEO) is a promising, environmentally friendly method to improve the surface characteristics of magnesium materials by the formation of oxide coatings. These PEO layers contain components of the applied electrolyte and can be shifted in their composition by increasing the concentration of the electrolyte constituents. Therefore, in contrast to the use of conventional low concentrated electrolytes, the process results in more stable protective coatings, in which electrolyte species are the dominating constitutes. In the present work, the influence of the composition of highly concentrated alkaline silicate electrolytes with additives of phosphate and glycerol on the quality of PEO layers on the magnesium alloy AZ31 was examined. The effect of ultrasound coupled into the electrolyte bath was also considered. The process was monitored by recording the electrical process variables with a transient recorder and by observation of the discharge phenomena on the sample surface with a camera. The study was conducted on the basis of a design of experiments. The effects of the process parameter variation are considered with regard to the coatings thickness, hardness and corrosion resistance. Information about the statistical significance of the effects of the parameters on the considered properties is obtained by an analysis of variance (ANOVA).

Producing ammonium chloride from coal or shale

Energy Technology Data Exchange (ETDEWEB)

Christenson, O L

1921-02-25

Process of producing ammonium chloride consists of mixing the substance to be treated with a chloride of an alkali or alkaline earth metal, free silica, water and free hydrochloric acid, heating the mixture until ammonium chloride distills off and collecting the ammonium chloride.

Nutrition and magnesium absorption

NARCIS (Netherlands)

Brink, E.J.

1992-01-01

The influence of various nutrients present in dairy products and soybean-based products on absorption of magnesium has been investigated. The studies demonstrate that soybean protein versus casein lowers apparent magnesium absorption in rats through its phytate component. However, true

Removal of phosphate from water by amine-functionalized copper ferrite chelated with La(III).

Science.gov (United States)

Gu, Wei; Li, Xiaodi; Xing, Mingchao; Fang, Wenkan; Wu, Deyi

2018-04-01

Eutrophication has become a worldwide environmental problem and removing phosphorus from water/wastewater before discharge is essential. The purpose of our present study was to develop an efficient material in terms of both phosphate adsorption capacity and magnetic separability. To this end, we first compared the performances of four spinel ferrites, including magnesium, zinc, nickel and copper ferrites. Then we developed a copper ferrite-based novel magnetic adsorbent, by synthesizing 1,6-hexamethylenediamine-functionalized copper ferrite(CuFe 2 O 4 ) via a single solvothermal synthesis process followed by LaCl 3 treatment. The materials were characterized with X-ray diffraction, transmission electron microscope, vibrating sample magnetometer, Fourier transform infrared spectra and N 2 adsorption-desorption. The maximum adsorption capacity of our material, calculated from the Langmuir adsorption isotherm model, attained 32.59mg/g with a saturation magnetization of 31.32emu/g. Data of adsorption kinetics were fitted well to the psuedo-second-order model. Effects of solution pH and coexisting anions (Cl - , NO 3 - , SO 4 2- ) on phosphate adsorption were also investigated, showing that our material had good selectivity for phosphate. But OH - competed efficiently with phosphate for adsorption sites. Furthermore, increasing both NaOH concentration and temperature resulted in an enhancement of desorption efficiency. Thus NaOH solution could be used to desorb phosphate adsorbed on the material for reuse, by adopting a high NaOH concentration and/or a high temperature. Copyright © 2017 Elsevier B.V. All rights reserved.

Ammonium nitrate-potassium nitrate system

Energy Technology Data Exchange (ETDEWEB)

Cady, H.H.

1981-01-01

A portion of the binary phase diagram for the system ammonium nitrate-potassium nitrate has been determined from -55/sup 0/C to 185/sup 0/C. Results are presented for the ammonium-nitrate-rich end of the system up to 30 wt% potassium nitrate.

True absorption of phosphorus from di calcium phosphate, mono ammonium phosphate, triple superphosphate and urea-phosphate in bovine by the radio phosphorus dilution technique

International Nuclear Information System (INIS)

Silva Filho, J.C. da.

1990-01-01

With the aim to study the utilization of alternative sources of phosphorus by ruminants. Twenty four males steers, with 250 Kg live weight and 18 months of age, were allocated in four groups of six animals each. The animals were housed in individual pens and received a diet containing chopped hay, corn and soybean meal, urea and mineral mixtures. The phosphate sources were added to supply 10 g of phosphorus per animal daily. The animals were injected intravenously and individually with 37 MBq of P-32 (N A 2 H P O 4 ) at the 20 th day of the experimental trial into the jugular vein. Blood and faces were collected and sampled at 24 hours intervals, for 8 days. Based on the specific activities in plasma and faces, the fecal endogenous loss and true phosphorus absorption were determined. (author)

Magnesium-DNA interactions and the possible relation of magnesium to carcinogenesis. Irradiation and free radicals.

Science.gov (United States)

Anastassopoulou, J; Theophanides, T

2002-04-01

Magnesium deficiency causes renal complications. The appearance of several diseases is related to its depletion in the human body. In radiotherapy, as well as in chemotherapy, especially in treatment of cancers with cis-platinum, hypomagnesaemia is observed. The site effects of chemotherapy that are due to hypomagnesaemia are decreased using Mg supplements. The role of magnesium in DNA stabilization is concentration dependent. At high concentrations there is an accumulation of Mg binding, which induces conformational changes leading to Z-DNA, while at low concentration there is deficiency and destabilization of DNA. The biological and clinical consequences of abnormal concentrations are DNA cleavage leading to diseases and cancer. Carcinogenesis and cell growth are also magnesium-ion concentration dependent. Several reports point out that the interaction of magnesium in the presence of other metal ions showed that there is synergism with Li and Mn, but there is magnesium antagonism in DNA binding with the essential metal ions in the order: Zn>Mg>Ca. In the case of toxic metals such as Cd, Ga and Ni there is also antagonism for DNA binding. It was found from radiolysis of deaerated aqueous solutions of the nucleoside 5'-guanosine monophosphate (5'-GMP) in the presence as well as in the absence of magnesium ions that, although the addition of hydroxyl radicals (*OH) has been increased by 2-fold, the opening of the imidazole ring of the guanine base was prevented. This effect was due to the binding of Mg2+ ions to N7 site of the molecule by stabilizing the five-member ring imitating cis-platinum. It was also observed using Fourier Transform Infrared spectroscopy, Raman spectroscopy and Fast Atom Bombardment mass spectrometry that *OH radicals subtract H atoms from the C1', C4' and C5' sites of the nucleotide. Irradiation of 5'-GMP in the presence of oxygen (2.5 x 10(-4) M) shows that magnesium is released from the complex. There is spectroscopic evidence that

Research of growth mechanism of ceramic coatings fabricated by micro-arc oxidation on magnesium alloys at high current mode

OpenAIRE

Wei-wei Chen; Ze-xin Wang; Lei Sun; Sheng Lu

2015-01-01

Micro-arc oxidation (MAO) coatings of ZK60 magnesium alloys were formed in a self-developed dual electrolyte composed of sodium silicate and phosphate at the high constant current of 1.8 A (15 A/dm2). The MAO process and growth mechanism were investigated by scanning electron microscopy (SEM) coupled with an energy dispersive spectrometer (EDS), confocal laser scanning microscopy and X-ray diffraction (XRD). The results indicate that the growth process of MAO coating mainly goes through “form...

Porous bioresorbable magnesium as bone substitute

Energy Technology Data Exchange (ETDEWEB)

Wen, C.E.; Yamada, Y.; Shimojima, K.; Chino, Y.; Hosokawa, H.; Mabuchi, M. [Inst. for Structural and Engineering Materials, National Inst. of Advanced Industrial Science and Technology, Nagoya (Japan)

2003-07-01

Recently magnesium has been recognized as a very promising biomaterial for bone substitutes because of its excellent properties of biocompatibility, biodegradability and bioresorbability. In the present study, magnesium foams were fabricated by using a powder metallurgical process. Scanning electron microscopy equipped with energy dispersive X-ray spectrometer (EDS) and compressive tester were used to characterize the porous magnesium. Results show that the Young's modulus and the peak stress of the porous magnesium increase with decreasing porosity and pore size. This study suggests that the mechanical properties of the porous magnesium with the low porosity of 35% and/or with the small pore size of about 70 {mu}m are close to those of human cancellous bones. (orig.)

Contribution of Drinking Water Softeners to Daily Phosphate Intake in Slovenia.

Science.gov (United States)

Jereb, Gregor; Poljšak, Borut; Eržen, Ivan

2017-10-06

The cumulative phosphate intake in a typical daily diet is high and, according to several studies, already exceeds recommended values. The exposure of the general population to phosphorus via drinking water is generally not known. One of the hidden sources of phosphorus in a daily diet is sodium polyphosphate, commonly used as a drinking water softener. In Slovenia, softening of drinking water is carried out exclusively within the internal (household) drinking water supply systems to prevent the accumulation of limescale. The aim of the study was to determine the prevalence of sodium phosphates in the drinking water in Slovenia in different types of buildings, to determine residents' awareness of the presence of chemical softeners in their drinking water, and to provide an exposure assessment on the phosphorus intake from drinking water. In the current study, the presence of phosphates in the samples of drinking water was determined using a spectrophotometric method with ammonium molybdate. In nearly half of the samples, the presence of phosphates as water softeners was confirmed. The measured concentrations varied substantially from 0.2 mg PO4/L to 24.6 mg PO4/L. Nearly 70% of the respondents were not familiar with the exact data on water softening in their buildings. It follows that concentrations of added phosphates should be controlled and the consumers should be informed of the added chemicals in their drinking water. The health risks of using sodium polyphosphate as a drinking water softener have not been sufficiently investigated and assessed. It is highly recommended that proper guidelines and regulations are developed and introduced to protect human health from adverse effects of chemicals in water intended for human consumption.

Small for Gestational Age and Magnesium: Intrauterine magnesium deficiency may induce metabolic syndrome in later life

Directory of Open Access Journals (Sweden)

Junji Takaya

2015-12-01

Full Text Available Magnesium deficiency during pregnancy as a result of insufficient or low intake of magnesium is common in developing and developed countries. Previous reports have shown that intracellular magnesium of cord blood platelets is lower among small for gestational age (SGA groups than that of appropriate for gestational age (AGA groups, suggesting that intrauterine magnesium deficiency may result in SGA. Additionally, the risk of adult-onset diseases such as insulin resistance syndrome is greater among children whose mothers were malnourished during pregnancy, and who consequently had a low birth weight. In a number of animal models, poor nutrition during pregnancy leads to offspring that exhibit pathophysiological changes similar to human diseases. The offspring of pregnant rats fed a magensium restricted diet have developed hypermethylation in the hepatic 11β-hydroxysteroid dehydrogenase-2 promoter. These findings indicate that maternal magnesium deficiencies during pregnancy influence regulation of non-imprinted genes by altering the epigenetic regulation of gene expression, thereby inducing different metabolic phenotypes. Magnesium deficiency during pregnancy may be responsible for not only maternal and fetal nutritional problems, but also lifelong consequences that affect the offspring throughout their life. Epidemiological, clinical, and basic research on the effects of magnesium deficiency now indicates underlying mechanisms, especially epigenetic processes.

Spectrophotometric determination of trace uranium in phosphate ore samples from kurum and uro areas, Nuba mountains, Sudan

International Nuclear Information System (INIS)

Mohamed, A. A.; Ali, A. H.; Altayeb, M. A. H.

2004-01-01

A method was proposed for the spectrophotometric determination of uranium content in phosphate ores. the method is based on the use of nitrogen (v) acid for leaching the rock, and treatment with ammonium carbonate solution, whereby uranium (Vi) is kept in solution as its carbonate complex. The ion-exchange technique was used for the recovery of uranium. Uranium was determined spectrophotometrically by measurement of the absorbance of the yellow uranium (Vi)-8-hydroxyquinolate complex at λ 425 nm. The procedure was used for the determination of trace uranium content in 30 phosphate ore samples collected from Kurun and Uro areas in Nuba mountains in Sudan. X-ray fluorescence technique was employed for the assessment of the method used. The spectrophotometric method results show a high similarity with those obtained by XRF technique. This agreement indicates that the procedure proposed here has been successfully applied for the determination of uranium in phosphate ores. (Author)

Magnesium in Prevention and Therapy

Science.gov (United States)

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

Corrosion of Magnesium in Multimaterial System

Energy Technology Data Exchange (ETDEWEB)

Joshi, Vineet V.; Agnew, Sean

2017-08-16

The TMS Magnesium Committee has been actively involved in presenting cutting-edge research and development and the latest trends related to magnesium and its alloys to industry and academia. Topics including magnesium alloy development, applications, mechanism of deformation and corrosion, thermomechanical processing, modelling, etc. have been captured year after year through the Magnesium Technology symposium and conference proceedings at TMS and through special topics in JOM. Every year, based on the unanimous endorsement from the industry and academia, a topic is selected to address the latest developments within this subject in JOM. In continuation with last year’s coverage of Advances and Achievements in In-Situ Analysis of Corrosions and Structure–Property Relationship in Mg Alloys,[1] this year’s topic focuses on the Corrosion of Magnesium in Multimaterial Systems. Magnesium, the lightest of all the structural materials, has garnered much interest in the transportation, electronics packaging, defense equipments and industries alike and are more commonly being incorporated in multimaterial design concepts.[2-4] However, the application of the same is limited due to its highly corrosive nature, and understanding and mitigating the corrosion of magnesium has been a major research challenge.

The reference range of serum, plasma and erythrocyte magnesium

Directory of Open Access Journals (Sweden)

Suzanna Immanuel

2006-12-01

Full Text Available The interest in the clinical importance of serum magnesium level has just recently begun with the analysis and findings of abnormal magnesium level in cardiovascular, metabolic and neuromuscular disorder. Although the serum level does not reflect the body magnesium level, but currently, only serum magnesium determination is widely used. Erythrocyte magnesium is considered more sensitive than serum magnesium as it reflects intracellular magnesium status. According to NCCLS (National Committee for Clinical Laboratory Standards every laboratory is recommended to have its own reference range for the tests it performs, including magnesium determination. The reference range obtained is appropriate for the population and affected by the method and technique. This study aimed to find the reference range of serum and plasma magnesium and also intracellular magnesium i.e. erythrocyte magnesium by direct method, and compare the results of serum and plasma magnesium. Blood was taken from 114-blood donor from Unit Transfusi Darah Daerah (UTDD Budhyarto Palang Merah Indonesia (PMI DKI Jakarta, consisted of 57 male and 57 female, aged 17 – 65 years, clinically healthy according to PMI donor criteria. Blood was taken from blood set, collected into 4 ml vacuum tube without anticoagulant for serum magnesium determination and 3 ml vacuum tube with lithium heparin for determination of erythrocyte and plasma magnesium Determination of magnesium level was performed with clinical chemistry auto analyzer Hitachi 912 by Xylidil Blue method colorimetrically. This study showed no significant difference between serum and heparinized plasma extra cellular magnesium. The reference range for serum or plasma magnesium was 1.30 – 2.00 mEq/L and for erythrocyte magnesium was 4.46 - 7.10 mEq/L. (Med J Indones 2006; 15:229-35Keywords: Reference range, extracellular magnesium, intracellular magnesium

Magnesium Tube Hydroforming

International Nuclear Information System (INIS)

Liewald, M.; Pop, R.; Wagner, S.

2007-01-01

Magnesium alloys can be considered as alternative materials towards achieving light weight structures with high material stiffness. The formability of two magnesium alloys, viz. AZ31 and ZM21 has been experimentally tested using the IHP forming process. A new die set up for hot IHP forming has been designed and the process experimentally investigated for temperatures up to 400 deg. C. Both alloys exhibit an increase in formability with increasing forming temperature. The effect of annealing time on materials forming properties shows a fine grained structure for sufficient annealing times as well as deterioration with a large increase at the same time. The IHP process has also been used to demonstrate practicability and feasibility for real parts from manufacture a technology demonstrator part using the magnesium alloy ZM21

Magnesium deficiency and increased inflammation: current perspectives

Directory of Open Access Journals (Sweden)

Nielsen FH

2018-01-01

Full Text Available Forrest H Nielsen Research Nutritionist Consultant, Grand Forks, ND, USA Abstract: Animal studies have shown that magnesium deficiency induces an inflammatory response that results in leukocyte and macrophage activation, release of inflammatory cytokines and acute-phase proteins, and excessive production of free radicals. Animal and in vitro studies indicate that the primary mechanism through which magnesium deficiency has this effect is through increasing cellular Ca2+, which is the signal that results in the priming of cells to give the inflammatory response. Primary pro-inflammatory cytokines such as tumor necrosis factor-α and interleukin (IL-1; the messenger cytokine IL-6; cytokine responders E-selectin, intracellular adhesion molecule-1 and vascular cell adhesion molecule-1; and acute-phase reactants C-reactive protein and fibrinogen have been determined to associate magnesium deficiency with chronic low-grade inflammation (inflammatory stress. When magnesium dietary intake, supplementation, and/or serum concentration suggest/s the presence of magnesium deficiency, it often is associated with low-grade inflammation and/or with pathological conditions for which inflammatory stress is considered a risk factor. When magnesium intake, supplementation, and/or serum concentration suggest/s an adequate status, magnesium generally has not been found to significantly affect markers of chronic low-grade inflammation or chronic disease. The consistency of these findings can be modified by other nutritional and metabolic factors that affect inflammatory and oxidative stress. In spite of this, findings to date provide convincing evidence that magnesium deficiency is a significant contributor to chronic low-grade inflammation that is a risk factor for a variety of pathological conditions such as cardiovascular disease, hypertension, and diabetes. Because magnesium deficiency commonly occurs in countries where foods rich in magnesium are not consumed in

Effect of Magnesium Hydride on the Corrosion Behavior of Pure Magnesium in 0.1 M NaCl Solution

OpenAIRE

Xu, Shanna; Dong, Junhua; Ke, Wei

2010-01-01

The effect of magnesium hydride on the corrosion behavior of pure magnesium in 0.1 M NaCl solution was investigated using the gas collection method, potentiostatic current decay test, and in situ Raman spectrum. The formation of magnesium hydride (MgH2, Mg2H4) was observed at the cathodic region. Applying anodic potential leads to decomposition of magnesium hydride. Magnesium hydride plays an important role on the negative difference effect (NDE) in both the cathodic and anodic regions.

Recent progress in fission product separation

International Nuclear Information System (INIS)

Raggenbass, A.

1964-01-01

Successful experiments have been done on the method described at Geneva in 1958. The process has been considerably improved: 1 - Initially, the caesium phospho tungstate precipitate was leached barium hydroxide in the centrifuge and this was followed by a distillation of ammonia in a concentrator. The barium hydroxide was then eliminated by carbonate precipitation and centrifugation. It has been proved that the ammonia distillation could be replaced by its evaporation during centrifugation, thus eliminating the need of a concentrator. It was then possible to carry out the carbonation on the solide-liquid mixture produced by the baryte water leaching. 2 - In applying the above process to the treatment of solutions derived from uranium molybdenum fuels, concentrating is to be recommended in order to hold the molybdenum in solution by complexing it with phosphoric acid. This complexing process provides a suspension of zirconium phosphate and ammonium phospho tungstate. These are separated by passing into a basic medium which precipitates the zirconium oxide, then turning back to an acid medium; the end of the treatment remains unchanged. 3 - Studies carried out in several countries on the exchange properties of hetero-polyacid salts have always met with difficulties as a result of the poor mechanical properties of these substances. This difficulty has been overcome by wrapping the ammonium phospho tungstate in a zirconium phosphate matrix. The exchanger obtained possesses: satisfactory mechanical properties, - a capacity of 0.1 milli equivalent per gram in concentrated nitric acid solution. It can be eluted and regenerated by a solution of an ammonium salt. The procedure for recovery of these various fission products is briefly the following: extraction of rare earths by di-2-ethyl hexyl phosphoric acid into dodecane at pH 2, the chemical impurities being complexed by citric acid, extraction of most of the magnesium at pH 4 by the same solvents the solvent being

Sustained drug release and electrochemical performance of ethyl cellulose-magnesium hydrogen phosphate composite

International Nuclear Information System (INIS)

Mohammad, Faruq; Arfin, Tanvir; Al-Lohedan, Hamad A.

2017-01-01

In this, a sol-gel method was applied to prepare ethyl cellulose-magnesium hydrogen phosphate (EC-MgHPO 4 ) composite that can have potential applications in the sensory, pharmaceutical, and biomedical sectors. The formed composite was thoroughly characterized by making use of the instrumental analysis such as UV–Vis, FT-IR, HRTEM, EDAX, SEM and XRD. For the composite, the other parameters determined includes the water uptake, porosity, thickness, bulk and tapped densities, angle of repose, Carr's index and Hausner ratio. From the results, the material found to exhibit good flowing properties with a Carr's index of 11.11%, Hausner ratio of 1.125, and angle of response of 33°. The EDAX spectrum and HRTEM analysis confirmed for the composite formation and the particles size is investigated to be around 52 nm. The surface porosity due to the EC matrices was confirmed by the SEM analysis, which further used for the loading of drug, Proguanil. In addition, the material's conductivity was studied by taking uni-univalent electrolyte solution (KCl and NaCl) indicated that the conductivity follows the order of KCl > NaCl, while the activation energy obtained from Arrhenius method resembled that the conductivity is strongly influenced by the electrolyte type used. We found from the analysis that, with a decrease in the size of hydrated radii of ions, the conductivity of EC-MgHPO 4 material also observed to be decreased in the order K + > Na + and the material proved to be mechanically stable and can be operated over a range of pHs, temperatures, and electrolyte solutions. Further, the drug loading and efficiency studies indicated that the material can trap up to 80% of Proguanil (antimalarial drug) applied for its loading. The Proguanil drug release profiles confirmed for the controlled and sustained release from the EC-MgHPO 4 matrix, as the material can release up to 87% of its total loaded drug over a 90 min period. Finally, the cell viability and

Sustained drug release and electrochemical performance of ethyl cellulose-magnesium hydrogen phosphate composite

Energy Technology Data Exchange (ETDEWEB)

Mohammad, Faruq, E-mail: fmohammad@ksu.edu.sa [Surfactant Research chair, Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Arfin, Tanvir, E-mail: t_arfin@neeri.res.in [Environmental Materials Division, CSIR-National Environmental Engineering Research Institute (CSIR-NEERI), Nehru Marg, Nagpur 440020 (India); Al-Lohedan, Hamad A. [Surfactant Research chair, Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia)

2017-02-01

In this, a sol-gel method was applied to prepare ethyl cellulose-magnesium hydrogen phosphate (EC-MgHPO{sub 4}) composite that can have potential applications in the sensory, pharmaceutical, and biomedical sectors. The formed composite was thoroughly characterized by making use of the instrumental analysis such as UV–Vis, FT-IR, HRTEM, EDAX, SEM and XRD. For the composite, the other parameters determined includes the water uptake, porosity, thickness, bulk and tapped densities, angle of repose, Carr's index and Hausner ratio. From the results, the material found to exhibit good flowing properties with a Carr's index of 11.11%, Hausner ratio of 1.125, and angle of response of 33°. The EDAX spectrum and HRTEM analysis confirmed for the composite formation and the particles size is investigated to be around 52 nm. The surface porosity due to the EC matrices was confirmed by the SEM analysis, which further used for the loading of drug, Proguanil. In addition, the material's conductivity was studied by taking uni-univalent electrolyte solution (KCl and NaCl) indicated that the conductivity follows the order of KCl > NaCl, while the activation energy obtained from Arrhenius method resembled that the conductivity is strongly influenced by the electrolyte type used. We found from the analysis that, with a decrease in the size of hydrated radii of ions, the conductivity of EC-MgHPO{sub 4} material also observed to be decreased in the order K{sup +} > Na{sup +} and the material proved to be mechanically stable and can be operated over a range of pHs, temperatures, and electrolyte solutions. Further, the drug loading and efficiency studies indicated that the material can trap up to 80% of Proguanil (antimalarial drug) applied for its loading. The Proguanil drug release profiles confirmed for the controlled and sustained release from the EC-MgHPO{sub 4} matrix, as the material can release up to 87% of its total loaded drug over a 90 min period. Finally, the

Comparisons Study of Phosphate Removal in Unaerated and Aerated High Calcium Steel Slag Filter System of Different pH Feed

Directory of Open Access Journals (Sweden)

Ahmad Siti Zu Nurain

2017-01-01

Full Text Available Excess phosphorus in water body will lead to eutrophication. This study investigated the phosphate removal efficiencies of unaerated and aerated filter systems using high composition of Calcium (Ca steel slag as the filter media at different pH values of the wastewater influents. Lab-scale filters were developed using 25 mg/L synthetic wastewater and weekly sampling was done to monitor the phosphate removal efficiencies together with the concentration of metals (Calcium (Ca and Magnesium (Mg. The results show that both unaerated and aerated systems have excellent phosphate removal efficiency at all acidic, neutral and alkaline pH feed, though unaerated systems removed slightly better compared to aerated systems; 76-98% and 69-97% respectively. The dominant phosphate removal mechanism for aerated systems was adsorption, meanwhilefor unaerated systems; both adsorption and precipitation for acidic and neutral pH, whileprecipitation was more dominant at basic pH. The performance of unaerated systems are slightly better compared to aerated systems, however, aerated systems are recommended to be applied when simultaneous removal of nutrients (phosphorus and nitrogen are concerned.

Effect of Poly(Vinyl Alcohol) Addition on the Properties of Hydrothermal Derived Calcium Phosphate Cement for Bone Filling Materials

Science.gov (United States)

Razali, N. N.; Sopyan, I.; Mel, M.; Salleh, H. M.; Rahman, M. M.; Singh, R.

2017-06-01

The effect of addition of poly(vinyl alcohol) on hydrothermal derived calcium phosphate cement has been studied. The precursors used to prepare the cement were calcium oxide (CaO) and ammonium dihydrogen phosphate (NH4H2PO4); the reaction was conducted in water at 80-100°C. To improve properties of CPC, poly(vinyl alcohol) (PVA) of 1wt% and 2wt% was added to the liquid phase of CPC and the results were compared to CPC without PVA addition. The addition of PVA was proved to bring remarkable effects on cohesion, setting time and mechanical strength of CPC which make it suitable physically for injectable bone filler applications.

Corrosion and protection of magnesium alloys

Energy Technology Data Exchange (ETDEWEB)

Ghali, E. [Laval Univ., Quebec City, PQ (Canada). Dept. of Mining and Metallurgy

2000-07-01

The oxide film on magnesium offers considerable surface protection in rural and some industrial environments and the corrosion rate lies between that of aluminum and low carbon steels. Galvanic coupling of magnesium alloys, high impurity content such as Ni, Fe, Cu and surface contamination are detrimental for corrosion resistance of magnesium alloys. Alloying elements can form secondary particles which are noble to the Mg matrix, thereby facilitating corrosion, or enrich the corrosion product thereby possibly inhibiting the corrosion rate. Bimetallic corrosion resistance can be increased by fluxless melt protection, choice of compatible alloys, insulating materials, and new high-purity alloys. Magnesium is relatively insensible to oxygen concentration. Pitting, corrosion in the crevices, filiform corrosion are observed. Granular corrosion of magnesium alloys is possible due to the cathodic grain-boundary constituent. More homogeneous microstructures tend to improve corrosion resistance. Under fatigue loading conditions, microcrack initiation in Mg alloys is related to slip in preferentially oriented grains. Coating that exclude the corrosive environments can provide the primary defense against corrosion fatigue. Magnesium alloys that contain neither aluminum nor zinc are the most SCC resistant. Compressive surface residual stresses as that created by short peening increase SCC resistance. Cathodic polarization or cladding with a SCC resistant sheet alloy are good alternatives. Effective corrosion prevention for magnesium alloy components and assemblies should start at the design stage. Selective surface preparation, chemical treatment and coatings are recommended. Oil application, wax coating, anodizing, electroplating, and painting are possible alternatives. Recently, it is found that a magnesium hydride layer, created on the magnesium surface by cathodic charging in aqueous solution is a good base for painting. (orig.)

Effect of Magnesium Hydride on the Corrosion Behavior of Pure Magnesium in 0.1 M NaCl Solution

Directory of Open Access Journals (Sweden)

Shanna Xu

2010-01-01

Full Text Available The effect of magnesium hydride on the corrosion behavior of pure magnesium in 0.1 M NaCl solution was investigated using the gas collection method, potentiostatic current decay test, and in situ Raman spectrum. The formation of magnesium hydride (MgH2, Mg2H4 was observed at the cathodic region. Applying anodic potential leads to decomposition of magnesium hydride. Magnesium hydride plays an important role on the negative difference effect (NDE in both the cathodic and anodic regions.

21 CFR 582.5431 - Magnesium oxide.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Magnesium oxide. 582.5431 Section 582.5431 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5431 Magnesium oxide. (a) Product. Magnesium oxide. (b) Conditions of use. This substance...

21 CFR 582.1431 - Magnesium oxide.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Magnesium oxide. 582.1431 Section 582.1431 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1431 Magnesium oxide. (a) Product. Magnesium oxide. (b) Conditions of use. This substance is...

21 CFR 582.5443 - Magnesium sulfate.

Science.gov (United States)

2010-04-01

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

Removal of nitrate, ammonia and phosphate from aqueous solutions in packed bed filter using biochar augmented sand media

Directory of Open Access Journals (Sweden)

El Hanandeh Ali

2017-01-01

Full Text Available Nutrients from wastewater are a major source of pollution because they can cause significant impact on the ecosystem. Accordingly, it is important that the nutrient concentrations are kept to admissible levels to the receiving environment. Often regulatory limits are set on the maximum allowable concentrations in the effluent. Therefore, wastewater must be treated to meet safe levels of discharge. In this study, laboratory investigation of the efficiency of packed bed filters to remove nitrate, ammonium and phosphate from aqueous solutions were conducted. Sand and sand augmented with hydrochloric acid treated biochar (SBC were used as packing media. Synthetic wastewater solution was prepared with PO43−, NO3−, NH4+ concentrations 20, 10, 50 mg/L, respectively. Each experiment ran for a period of five days; samples from the effluent were collected on alternate days. All experiments were duplicated. Over the experiment period, the average removal efficiency of PO43−, NO3−, NH4+ were 99.2%, 72.9%, 96.7% in the sand packed columns and 99.2%, 82.3%, 97.4% in the SBC packed columns, respectively. Although, the presence of biochar in the packing media had little effect on phosphate and ammonium removal, it significantly improved nitrate removal.

Start-up of simultaneous removal of ammonium and sulfate from an anaerobic ammonium oxidation (anammox) process in an anaerobic up-flow bioreactor

Energy Technology Data Exchange (ETDEWEB)

Yang Zhiquan [College of Environmental Science and Engineering, South China University of Technology, Guangzhou, Guangdong 510006 (China); Zhou Shaoqi, E-mail: fesqzhou@scut.edu.cn [College of Environmental Science and Engineering, South China University of Technology, Guangzhou, Guangdong 510006 (China); State Key Laboratory of Subtropical Building Science, South China University of Technology, Guangzhou, Guangdong 510640 (China); Sun Yanbo [College of Environmental Science and Engineering, South China University of Technology, Guangzhou, Guangdong 510006 (China)

2009-09-30

A laboratory testing of simultaneous removal of ammonium and sulfate (SRAS) was studied from an anammox process in an anaerobic bioreactor filled with granular activated carbon. Two different phases of experiment were investigated to start up the SRAS process, and final batch tests were performed to analyze the SRAS process. The experiment included an anammox process and an SRAS process. During the anammox process, the highest removal efficiency of ammonium and nitrite was up to 97 and 98%, respectively. After 160 days in the stationary phase of anammox process, the ratio of ammonium to nitrite consumption was approximately 1:1.15, which is much higher than 1:1.32 in the traditional anammox process. The extra electron acceptor, such as sulfate, was thought to react with ammonium by bacteria. Synthetic wastewater containing ammonium chlorine and sodium sulfate was used as the feed for the bioreactor in the second phase of experiment. During the SRAS process, the influent concentrations of ammonium and sulfate were controlled to be 50-60 and 210-240 mg L{sup -1} respectively. After start-up and acclimatization of this process for 60 days, the average effluent concentrations of ammonium and sulfate were 30 and 160 mg L{sup -1}, respectively. The simultaneous ammonium and sulfate removal was detected in the reactor. In order to further validate the biochemical interaction between ammonium and sulfate, batch tests was carried out. Abiotic tests were carried out to demonstrate that the pure chemical action between ammonium and sulfate without microorganism was not possible. Biotic assays with different ammonium and sulfate concentrations were further investigated that high concentrations of ammonium and sulfate could promote simultaneous removal of ammonium and sulfate. And elemental sulfur and nitrogen gas as the products measured in the SRAS process helped to demonstrate the occurrence of new interaction between nitrogen and sulfur. The new process of SRAS in the

Start-up of simultaneous removal of ammonium and sulfate from an anaerobic ammonium oxidation (anammox) process in an anaerobic up-flow bioreactor

International Nuclear Information System (INIS)

Yang Zhiquan; Zhou Shaoqi; Sun Yanbo

2009-01-01

A laboratory testing of simultaneous removal of ammonium and sulfate (SRAS) was studied from an anammox process in an anaerobic bioreactor filled with granular activated carbon. Two different phases of experiment were investigated to start up the SRAS process, and final batch tests were performed to analyze the SRAS process. The experiment included an anammox process and an SRAS process. During the anammox process, the highest removal efficiency of ammonium and nitrite was up to 97 and 98%, respectively. After 160 days in the stationary phase of anammox process, the ratio of ammonium to nitrite consumption was approximately 1:1.15, which is much higher than 1:1.32 in the traditional anammox process. The extra electron acceptor, such as sulfate, was thought to react with ammonium by bacteria. Synthetic wastewater containing ammonium chlorine and sodium sulfate was used as the feed for the bioreactor in the second phase of experiment. During the SRAS process, the influent concentrations of ammonium and sulfate were controlled to be 50-60 and 210-240 mg L -1 respectively. After start-up and acclimatization of this process for 60 days, the average effluent concentrations of ammonium and sulfate were 30 and 160 mg L -1 , respectively. The simultaneous ammonium and sulfate removal was detected in the reactor. In order to further validate the biochemical interaction between ammonium and sulfate, batch tests was carried out. Abiotic tests were carried out to demonstrate that the pure chemical action between ammonium and sulfate without microorganism was not possible. Biotic assays with different ammonium and sulfate concentrations were further investigated that high concentrations of ammonium and sulfate could promote simultaneous removal of ammonium and sulfate. And elemental sulfur and nitrogen gas as the products measured in the SRAS process helped to demonstrate the occurrence of new interaction between nitrogen and sulfur. The new process of SRAS in the inorganic

Imparting passivity to vapor deposited magnesium alloys

Science.gov (United States)

Wolfe, Ryan C.

Magnesium has the lowest density of all structural metals. Utilization of low density materials is advantageous from a design standpoint, because lower weight translates into improved performance of engineered products (i.e., notebook computers are more portable, vehicles achieve better gas mileage, and aircraft can carry more payload). Despite their low density and high strength to weight ratio, however, the widespread implementation of magnesium alloys is currently hindered by their relatively poor corrosion resistance. The objective of this research dissertation is to develop a scientific basis for the creation of a corrosion resistant magnesium alloy. The corrosion resistance of magnesium alloys is affected by several interrelated factors. Among these are alloying, microstructure, impurities, galvanic corrosion effects, and service conditions, among others. Alloying and modification of the microstructure are primary approaches to controlling corrosion. Furthermore, nonequilibrium alloying of magnesium via physical vapor deposition allows for the formation of single-phase magnesium alloys with supersaturated concentrations of passivity-enhancing elements. The microstructure and surface morphology is also modifiable during physical vapor deposition through the variation of evaporation power, pressure, temperature, ion bombardment, and the source-to-substrate distance. Aluminum, titanium, yttrium, and zirconium were initially chosen as candidates likely to impart passivity on vapor deposited magnesium alloys. Prior to this research, alloys of this type have never before been produced, much less studied. All of these metals were observed to afford some degree of corrosion resistance to magnesium. Due to the especially promising results from nonequilibrium alloying of magnesium with yttrium and titanium, the ternary magnesium-yttrium-titanium system was investigated in depth. While all of the alloys are lustrous, surface morphology is observed under the scanning

Separation of magnesium from magnesium chloride and zirconium and/or hafnium subchlorides in the production of zirconium and/or hafnium sponge metal

International Nuclear Information System (INIS)

Abodishish, H.A.M.; Adams, R.J.; Kearl, S.R.

1992-01-01

This patent describes the producing of a refractory metal wherein a sponge refractory metal is produced as an intermediate product by the use of magnesium with the incidental production of magnesium chloride, and wherein residual magnesium is separated from the magnesium chloride and from refractory metal to a vacuum distillation step which fractionally distills the magnesium, the magnesium chloride, and the metal sub-chlorides; the steps of: recovering fractionally distilled vapors of magnesium chloride and metal sub-chlorides from a sponge refractory metal; separately condensing the vapors as separately recovered; and recycling the separately recovered magnesium at a purity of at least about 96%

Removal of phosphate from greenhouse wastewater using hydrated lime.

Science.gov (United States)

Dunets, C Siobhan; Zheng, Youbin

2014-01-01

Phosphate (P) contamination in nutrient-laden wastewater is currently a major topic of discussion in the North American greenhouse industry. Precipitation of P as calcium phosphate minerals using hydrated lime could provide a simple, inexpensive method for retrieval. A combination of batch experiments and chemical equilibrium modelling was used to confirm the viability of this P removal method and determine lime addition rates and pH requirements for greenhouse wastewater of varying nutrient compositions. Lime: P ratio (molar ratio of CaMg(OH)₄: PO₄‒P) provided a consistent parameter for estimating lime addition requirements regardless of initial P concentration, with a ratio of 1.5 providing around 99% removal of dissolved P. Optimal P removal occurred when lime addition increased the pH from 8.6 to 9.0, suggesting that pH monitoring during the P removal process could provide a simple method for ensuring consistent adherence to P removal standards. A Visual MINTEQ model, validated using experimental data, provided a means of predicting lime addition and pH requirements as influenced by changes in other parameters of the lime-wastewater system (e.g. calcium concentration, temperature, and initial wastewater pH). Hydrated lime addition did not contribute to the removal of macronutrient elements such as nitrate and ammonium, but did decrease the concentration of some micronutrients. This study provides basic guidance for greenhouse operators to use hydrated lime for phosphate removal from greenhouse wastewater.

Synthesis Magnesium Hydroxide Nanoparticles and Cellulose Acetate- Mg(OH2-MWCNT Nanocomposite

Directory of Open Access Journals (Sweden)

M. Ghorbanali

2015-04-01

Full Text Available Mg(OH2 nanoparticles were synthesized by a rapid microwave reaction. The effect of sodium dodecyl sulfonate (SDS as anionic surfactant and cetyl tri-methyl ammonium bromide (CTAB as cationic surfactant on the morphology of magnesium hydroxide nanostructures was investigated. Multi wall carbon nano tubes was organo-modified for better dispersion in cellulose acetate matrix. The influence of Mg(OH2 nanoparticles and modified multi wall carbon nano tubes (MWCNT on the thermal stability of the cellulose acetate (CA matrix was studied using thermo-gravimetric analysis (TGA. Nanostructures were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM and Fourier transform infrared (FT-IR spectroscopy. Thermal decomposition of the nanocomposites shift towards higher temperature in the presence of Mg(OH2 nanostructures. The enhancement of thermal stability of nanocomposites is due to the endothermic decomposition of Mg(OH2 and release of water which dilutes combustible gases.

In vitro and in vivo evaluation of a new nanocomposite, containing high density polyethylene, tricalcium phosphate, hydroxyapatite, and magnesium oxide nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Pourdanesh, Fereydoun [Dental Research Center, Research Institute of Dental Sciences, Shahid Beheshti University of Medical Sciences, Tehran 8916733754 (Iran, Islamic Republic of); Jebali, Ali, E-mail: alijebal2011@gmail.com [Department of Medical Physics and Biomedical Engineering, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Hekmatimoghaddam, Seyedhossein [Department of Laboratory Sciences, School of Paramedicine, Shahid Sadoughi University of Medical Sciences, Yazd (Iran, Islamic Republic of); Allaveisie, Azra [Department of Genetics, Research and Clinical Center for Infertility, Shahid Sadoughi University of Medical Sciences, Yazd (Iran, Islamic Republic of)

2014-07-01

In this study, a new nanocomposite, which contained high density polyethylene (HDPE), tricalcium phosphate (Ca{sub 3}(PO{sub 4}){sub 2}) nanoparticles (TCP NPs), hydroxyapatite nanoparticles (HA NPs), and magnesium oxide nanoparticles (MgO NPs) was prepared. As in vitro experiment, human osteoblasts (HOB) cells were exposed to pristine HDPE and its nanocomposite for a period of 1, 4, and 7 days at 37 °C, and then different assays were carried out, including osteoblast cell proliferation, Trypan blue staining, cell viability, alkaline phosphatase (ALP), and cell adhesion. Antibacterial property of pristine HDPE and its nanocomposite was evaluated, and also their mechanical properties were measured after 2 and 4 months. As in vivo experiment, pristine HDPE and its nanocomposite were separately implanted on calvarium bone of rabbits, and tissue inflammation and osteogenesis were investigated after 2, 4, and 6 months. In case of HOB cells treated with HDPE or nanocomposite, as incubation time was increased, cell proliferation, live/dead ratio, and cell viability were decreased. But, the ALP activity and cell adhesion of HOB cells which treated with nanocomposite were raised after increase of incubation time. This study demonstrated that although the mechanical properties of nanocomposite were similar to HDPE sheet, but their antibacterial property was not similar. The in vivo experiment showed that both pristine HDPE and its nanocomposite had same inflammation responses. Interestingly, osteogenesis was observed after 2 months at bone/nanocomposite interface, and was highly increased after 4 and 6 months. It must be noted that such pattern was not seen at bone/HDPE interface. - Highlights: • The effect of various nanoparticles like as Ca{sub 3}(PO{sub 4}){sub 2}, hydroxyapatite, and MgO was studied. • HDPE/TCP/HA/MgO nanocomposite was biocompatible. • The effect of nanoparticles showed high antibacterial property.

In vitro and in vivo evaluation of a new nanocomposite, containing high density polyethylene, tricalcium phosphate, hydroxyapatite, and magnesium oxide nanoparticles

International Nuclear Information System (INIS)

Pourdanesh, Fereydoun; Jebali, Ali; Hekmatimoghaddam, Seyedhossein; Allaveisie, Azra

2014-01-01

In this study, a new nanocomposite, which contained high density polyethylene (HDPE), tricalcium phosphate (Ca 3 (PO 4 ) 2 ) nanoparticles (TCP NPs), hydroxyapatite nanoparticles (HA NPs), and magnesium oxide nanoparticles (MgO NPs) was prepared. As in vitro experiment, human osteoblasts (HOB) cells were exposed to pristine HDPE and its nanocomposite for a period of 1, 4, and 7 days at 37 °C, and then different assays were carried out, including osteoblast cell proliferation, Trypan blue staining, cell viability, alkaline phosphatase (ALP), and cell adhesion. Antibacterial property of pristine HDPE and its nanocomposite was evaluated, and also their mechanical properties were measured after 2 and 4 months. As in vivo experiment, pristine HDPE and its nanocomposite were separately implanted on calvarium bone of rabbits, and tissue inflammation and osteogenesis were investigated after 2, 4, and 6 months. In case of HOB cells treated with HDPE or nanocomposite, as incubation time was increased, cell proliferation, live/dead ratio, and cell viability were decreased. But, the ALP activity and cell adhesion of HOB cells which treated with nanocomposite were raised after increase of incubation time. This study demonstrated that although the mechanical properties of nanocomposite were similar to HDPE sheet, but their antibacterial property was not similar. The in vivo experiment showed that both pristine HDPE and its nanocomposite had same inflammation responses. Interestingly, osteogenesis was observed after 2 months at bone/nanocomposite interface, and was highly increased after 4 and 6 months. It must be noted that such pattern was not seen at bone/HDPE interface. - Highlights: • The effect of various nanoparticles like as Ca 3 (PO 4 ) 2 , hydroxyapatite, and MgO was studied. • HDPE/TCP/HA/MgO nanocomposite was biocompatible. • The effect of nanoparticles showed high antibacterial property

Assessment of serum magnesium levels and its outcome in neonates of eclamptic mothers treated with low-dose magnesium sulfate regimen

Science.gov (United States)

Das, Monalisa; Chaudhuri, Patralekha Ray; Mondal, Badal C.; Mitra, Sukumar; Bandyopadhyay, Debasmita; Pramanik, Sushobhan

2015-01-01

Objectives: Magnesium historically has been used for treatment and/or prevention of eclampsia. Considering the low body mass index of Indian women, a low-dose magnesium sulfate regime has been introduced by some authors. Increased blood levels of magnesium in neonates is associated with increased still birth, early neonatal death, birth asphyxia, bradycardia, hypotonia, gastrointestinal hypomotility. The objective of this study was to assess safety of low-dose magnesium sulfate regimen in neonates of eclamptic mothers treated with this regimen. Materials and Methods: This was a cross-sectional observational study of 100 eclampsia patients and their neonates. Loading dose and maintenance doses of magnesium sulfate were administered to patients by combination of intravenous and intramuscular routes. Maternal serum and cord blood magnesium levels were estimated. Neonatal outcome was assessed. Results: Bradycardia was observed in 18 (19.15%) of the neonates, 16 (17.02%) of the neonates were diagnosed with hypotonia. Pearson Correlation Coefficient showed Apgar scores decreased with increase in cord blood magnesium levels. Unpaired t-test showed lower Apgar scores with increasing dose of magnesium sulfate. The Chi-square/Fisher's exact test showed significant increase in hypotonia, birth asphyxia, intubation in delivery room, Neonatal Intensive Care Unit (NICU) care requirement, with increasing dose of magnesium sulfate. (P ≤ 0.05). Conclusion: Several neonatal complications are significantly related to increasing serum magnesium levels. Overall, the low-dose magnesium sulfate regimen was safe in the management of eclamptic mothers, without toxicity to their neonates. PMID:26600638

Phosphate removal from aqueous solutions using polyaniline/ Ni 0.5 Zn 0.5 Fe 2 O 4 magnetic nanocomposite

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Mohammad Hossein Tarmahi

2017-05-01

Full Text Available Background: Phosphorus is an indispensable element for the growth of animals and plants. There are several environmental problems related to phosphate; therefore, the technical and economic methods of removing phosphate are of great importance. This study evaluated the efficiency of polyaniline/ Ni0.5Zn0.5Fe2O4 magnetic nanocomposite in removing phosphate from aqueous environments. Methods: The adsorbent was characterized by several methods, including X-ray diffraction (XRD, scanning electron microscopy (SEM, vibrating sample magnetometer (VSM, and Fourier transform infrared (FT-IR spectroscopy. Then, the potential of the adsorbentto adsorb phosphate was investigated. The effects of the parameters of contact time (5-60 minutes, pH (3-9, adsorbent dosage (0.05-0.6 g, and initial phosphate concentration (2-100 mg/L on the phosphate removal yield were studied. All phosphate ion concentrations were measured using the ammonium molybdate spectrophotometric method. Results: The results showed that a time of 30 minutes, pH of 5, and adsorbent dose of 0.4 g were the optimum conditions for phosphate removal through adsorption. Increasing the initial concentration of phosphate from 2 to 100 mg/L decreased the removal efficiency from 90.3% to 32%. The experimental data was fitted well with the Freundlich isotherm model (R2 = 0.997. Conclusion: Polyaniline/Ni0.5Zn0.5Fe2O4 magnetic nanocomposite removes phosphate from aqueous solutions with a simple and environmentally benign procedure. The maximum adsorption capacity based on Langmuir isotherm (R2 = 0.931 is 85.4 mg/g. This magnetic nanocomposite is applicable in managing water resource pollution caused by phosphate ions.

Ion Implantation of Calcium and Zinc in Magnesium for Biodegradable Implant Applications

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Sahadev Somasundaram

2018-01-01

Full Text Available In this study, magnesium was implanted with calcium-ion and zinc-ion at fluences of 1015, 1016, and 1017 ion·cm−2, and its in vitro degradation behaviour was evaluated using electrochemical techniques in simulated body fluid (SBF. Rutherford backscattering spectrometry (RBS revealed that the implanted ions formed layers within the passive magnesium-oxide/hydroxide layers. Electrochemical impedance spectroscopy (EIS results demonstrated that calcium-ion implantation at a fluence of 1015 ions·cm−2 increased the polarisation resistance by 24%, but higher fluences showed no appreciable improvement. In the case of zinc-ion implantation, increase in the fluence decreased the polarisation resistance. A fluence of 1017 ion·cm−2 decreased the polarisation resistance by 65%, and fluences of 1015 and 1016 showed only marginal effect. Similarly, potentiodynamic polarisation results also suggested that low fluence of calcium-ion decreased the degradation rate by 38% and high fluence of zinc-ion increased the degradation rate by 61%. All the post-polarized ion-implanted samples and the bare metal revealed phosphate and carbonate formation. However, the improved degradative behaviour in calcium-ion implanted samples can be due to a relatively better passivation, whereas the reduction in degradation resistance in zinc-ion implanted samples can be attributed to the micro-galvanic effect.

Improved cytotoxicity testing of magnesium materials

Energy Technology Data Exchange (ETDEWEB)

Fischer, Janine [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Department for Structural Research on Macromolecules, Max-Planck Str. 1, D - 21502 Geesthacht (Germany); Proefrock, Daniel [Helmholtz-Zentrum Geesthacht, Institute for Coastal Research, Department for Marine Bioanalytical Chemistry, Max-Planck Str. 1, D - 21502 Geesthacht (Germany); Hort, Norbert [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Department for Magnesium Processing, Max-Planck Str. 1, D - 21502 Geesthacht (Germany); Willumeit, Regine; Feyerabend, Frank [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Department for Structural Research on Macromolecules, Max-Planck Str. 1, D - 21502 Geesthacht (Germany)

2011-06-25

Metallic magnesium (Mg) and its alloys are highly suitable for medical applications as biocompatible and biodegradable implant materials. Magnesium has mechanical properties similar to bone, stimulates bone regeneration, is an essential non-toxic element for the human body and degrades completely within the body environment. In consequence, magnesium is a promising candidate as implant material for orthopaedic applications. Protocols using the guideline of current ISO standards should be carefully evaluated when applying them for the characterization of the cytotoxic potential of degradable magnesium materials. For as-cast material we recommend using 10 times more extraction medium than recommended by the ISO standards to obtain reasonable results for reliable cytotoxicity rankings of degradable materials in vitro. In addition primary isolated human osteoblasts or mesenchymal stem cells should be used to test magnesium materials.

Improved cytotoxicity testing of magnesium materials

International Nuclear Information System (INIS)

Fischer, Janine; Proefrock, Daniel; Hort, Norbert; Willumeit, Regine; Feyerabend, Frank

2011-01-01

Metallic magnesium (Mg) and its alloys are highly suitable for medical applications as biocompatible and biodegradable implant materials. Magnesium has mechanical properties similar to bone, stimulates bone regeneration, is an essential non-toxic element for the human body and degrades completely within the body environment. In consequence, magnesium is a promising candidate as implant material for orthopaedic applications. Protocols using the guideline of current ISO standards should be carefully evaluated when applying them for the characterization of the cytotoxic potential of degradable magnesium materials. For as-cast material we recommend using 10 times more extraction medium than recommended by the ISO standards to obtain reasonable results for reliable cytotoxicity rankings of degradable materials in vitro. In addition primary isolated human osteoblasts or mesenchymal stem cells should be used to test magnesium materials.

On the ionization of interstellar magnesium

International Nuclear Information System (INIS)

Gurzadyan, G.A.

1977-01-01

It has been shown that two concentric ionization zones of interstellar magnesium must exist around each star: internal, with a radius coinciding with that of the zone of hydrogen ionization Ssub(H); and external, with a radius greater than Ssub(H), by one order. Unlike interstellar hydrogen, interstellar magnesium is ionized throughout the Galaxy. It also transpires that the ionizing radiation of ordinary hot stars cannot provide for the observed high degree of ionization of interstellar magnesium. The discrepance can be eliminated by assuming the existence of circumstellar clouds or additional ionization sources of interstellar magnesium (X-ray background radiation, high-energy particles, etc.). Stars of the B5 and BO class play the main role in the formation of ionization zones of interstellar magnesium; the contribution of O class stars is negligible (<1%). (Auth.)

Sources et marché du sulfate d'ammonium Sources of and Market for Ammonium Sulfate

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Loussouarn C.

2006-11-01

Full Text Available Engrais azoté le plus utilisé dans le monde jusqu'en 1970, le sulfate d'ammonium ne représente plus aujourd'hui que 4 % de la fertilisation azotée. Avec une teneur en azote de 21 % seulement, il a été peu à peu remplacé comme engrais universel par des produits plus concentrés, notamment l'urée et le nitrate d'ammonium. Obtenu pour plus de 40 % comme sous-produit dans la synthèse de monomères comme le caprolactame, l'acrylonitrile ou le méthacrylate de méthyle, et pour près de 10 % dans le traitement des gaz de cokerie, sa production dépend largement des développements du marché des fibres synthétiques, et, dans une moindre mesure, de la sidérurgie et de la métallurgie. Dans les pays développés, où la production est essentiellement fatale, le volume du marché est et sera plus fonction de la disponibilité du sulfate d'ammonium que de la demande ou de facteurs de marché; sa consommation ne résidera plus que dans des applications spécifiques pour lesquelles il sera bien adapté. Par contre, l'intérêt croissant pour compenser le déficit en soufre de certains sols, et les qualités agronomiques propres du sulfate d'ammonium laissent entrevoir la possibilité d'un essor de son utilisation dans certaines régions en voie de développernent. Ammonium sulfate was the most worldwide nitrogenous fertilizer used up to 1970. Today, it makes up only 4% of nitrogenous fertilization. With a nitrogen content of only 21%, it has gradually been replaced as a universal fertilizer by more concentrated products, particularly urea and ammonium nitrate. More than 40% of the ammonium sulfate is obtained as a by-product from the synthesis of monomers such as caprolactam, acrylonitrile or methyl methacrylate, and nearly 10% from coking gas processing. Its production depends extensively on the development of the market for synthetic fibers and, to a lesser extent, on the steel and metallurgical industries. In the industrialized countries

Magnesium balances and 28Mg studies in man

International Nuclear Information System (INIS)

Spencer, H.; Schwartz, R.; Osis, D.

1988-01-01

The intestinal absorption of magnesium was determined under strictly controlled dietary conditions in patients with normal renal function and also in patients with chronic renal failure. The average net absorption of magnesium of patients with normal renal function, expressed as percent of the magnesium intake, was 48.5%, while that of patients with chronic renal failure was significantly lower, 17%. Increasing the calcium intake from a low calcium intake of 200 mg/day to different higher intake levels up to 2000 mg/day did not change the magnesium balance nor the net absorption of magnesium of both types of patients. The lack of effect of the higher calcium intake on the absorption of magnesium was confirmed in 28 Mg studies in which an oral dose of 28 Mg, as the chloride, was given. The excretion of the absorbed magnesium into the intestine, the endogenous fecal magnesium, was low. Also, increasing the phosphorus intake up to 2000 mg/day in subjects with normal renal function did not affect the magnesium balance, regardless of the calcium intake

Aluminum Hydroxide and Magnesium Hydroxide

Science.gov (United States)

Aluminum Hydroxide, Magnesium Hydroxide are antacids used together to relieve heartburn, acid indigestion, and upset stomach. They ... They combine with stomach acid and neutralize it. Aluminum Hydroxide, Magnesium Hydroxide are available without a prescription. ...

Development of technology for ammonium nitrate dissociation process

International Nuclear Information System (INIS)

Zakharkin, B.S.; Varykhanov, V.P.; Kucherenko, V.S.; Solov'yeva, L.N.; Revyakin, V.V.

2000-01-01

Ammonia and ammonium carbonate are frequently used as reagents in fuel production and processing of liquid radioactive wastes. In particular, liquid radioactive wastes that contain ammonium nitrate are generated during operations of metal precipitation. In closed vessels at elevated temperature, for example in evaporators or deposits in tubing, ammonium nitrate may explode due to generation of gaseous nitrogen oxides [2]. In this connection, steps have to be taken to rule out conditions that result in explosion. To do that, ammonium nitrate should be removed even prior to the initial stage of its formation. This report gives results of development of a method of dissociating ammonium nitrate