Science.gov

Sample records for 21s beta-tricalcium phosphate

  1. Novel highly biodegradable biphasic tricalcium phosphates composed of alpha-tricalcium phosphate and beta-tricalcium phosphate.

    PubMed

    Li, Yanbao; Weng, Wenjian; Tam, Kim Chiu

    2007-03-01

    Novel biodegradable biphasic tricalcium phosphates (BTCP) composed of alpha-tricalcium phosphate (alpha-TCP) and beta-tricalcium phosphate (beta-TCP) were successfully synthesized by heating amorphous calcium phosphate precursors with different structures at 800 degrees C for 3 h. The ratio of alpha-TCP and beta-TCP in the calcium phosphate particle can be controlled by aging time and pH value during synthesis of the amorphous precursor.

  2. Calcium phosphate cements: study of the beta-tricalcium phosphate--monocalcium phosphate system.

    PubMed

    Mirtchi, A A; Lemaitre, J; Terao, N

    1989-09-01

    The possibility of making cements based on beta-tricalcium phosphate (beta-TCP), a promising bone graft material, was investigated. Upon admixture with water, beta-TCP/monocalcium phosphate monohydrate (MCPM) mixtures were found to set and harden like conventional hydraulic cements. Beta-TCP powders with larger particle size, obtained by sintering at higher temperatures, increased the ultimate strength of the cement. Results show that setting occurs after dissolution of MCPM, as a result of the precipitation of dicalcium phosphate dihydrate (DCPD) in the paste. The ultimate tensile strength of the hardened cement is proportional to the amount of DCPD formed. Upon ageing above 40 degrees C, DCPD transforms progressively into anhydrous dicalcium phosphate (DCP), thereby decreasing the strength. Ageing of the pastes in 100% r.h. results in a decay of the mechanical properties. This can be ascribed to an intergranular dissolution of the beta-TCP aggregates as a result of the pH lowering brought about by the MCPM to DCPD conversion.

  3. Sintering and robocasting of beta-tricalcium phosphate scaffoldsfor orthopaedic applications

    SciTech Connect

    Miranda, Pedro; Saiz, Eduardo; Gryn Karol; Tomsia, Antoni P.

    2005-11-01

    {beta}-tricalcium phosphate ({beta}-TCP) scaffolds with designed, three-dimensional (3-D) geometry and mesoscale porosity have been fabricated by direct-write assembly (robocasting) techniques. Concentrated {beta}-TCP inks with suitable viscoelastic properties were developed to enable the fabrication of the complex 3-D structures. A comprehensive study of the sintering behavior of TCP as a function of the calcium content in the starting powder was also carried out, and the optimal heat treatment for fabricating scaffolds with dense {beta}-TCP rods has been determined. Such analysis provides clues to controlling the microstructure of the fabricated structures and, therefore, enabling the fabrication by robocasting of TCP scaffolds with tailored performance for bone tissue engineering applications.

  4. Collagen/Beta-Tricalcium Phosphate Based Synthetic Bone Grafts via Dehydrothermal Processing

    PubMed Central

    Sarikaya, Burcu; Aydin, Halil Murat

    2015-01-01

    Millions of patients worldwide remain inadequately treated for bone defects related to factors such as disease or trauma. The drawbacks of metallic implant and autograft/allograft use have steered therapeutic approaches towards tissue engineering solutions involving tissue regeneration scaffolds. This study proposes a composite scaffold with properties tailored to address the macro- and microenvironmental conditions deemed necessary for successful regeneration of bone in defect areas. The biodegradable scaffold composed of porous beta-tricalcium phosphate particles and collagen type I fibers is prepared from a mixture of collagen type-I and β-tricalcium phosphate (β-TCP) particles via lyophilization, followed by dehydrothermal (DHT) processing. The effects of both sterilization via gamma radiation and the use of DHT processing to achieve cross-linking were investigated. The impact of the chosen fabrication methods on scaffold microstructure and β-TCP particle-collagen fiber combinations were analyzed using X-ray diffractometry (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and microcomputerized tomography (µ-CT). Electron spinning resonance (ESR) analysis was used to investigate free radicals formation following sterilization. Results revealed that the highly porous (65% porosity at an average of 100 µm pore size), mechanically adequate, and biocompatible scaffolds can be utilized for bone defect repairs. PMID:26504812

  5. Collagen/Beta-Tricalcium Phosphate Based Synthetic Bone Grafts via Dehydrothermal Processing.

    PubMed

    Sarikaya, Burcu; Aydin, Halil Murat

    2015-01-01

    Millions of patients worldwide remain inadequately treated for bone defects related to factors such as disease or trauma. The drawbacks of metallic implant and autograft/allograft use have steered therapeutic approaches towards tissue engineering solutions involving tissue regeneration scaffolds. This study proposes a composite scaffold with properties tailored to address the macro- and microenvironmental conditions deemed necessary for successful regeneration of bone in defect areas. The biodegradable scaffold composed of porous beta-tricalcium phosphate particles and collagen type I fibers is prepared from a mixture of collagen type-I and β-tricalcium phosphate (β-TCP) particles via lyophilization, followed by dehydrothermal (DHT) processing. The effects of both sterilization via gamma radiation and the use of DHT processing to achieve cross-linking were investigated. The impact of the chosen fabrication methods on scaffold microstructure and β-TCP particle-collagen fiber combinations were analyzed using X-ray diffractometry (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and microcomputerized tomography (µ-CT). Electron spinning resonance (ESR) analysis was used to investigate free radicals formation following sterilization. Results revealed that the highly porous (65% porosity at an average of 100 µm pore size), mechanically adequate, and biocompatible scaffolds can be utilized for bone defect repairs.

  6. Structural characterization of room-temperature synthesized nano-sized beta-tricalcium phosphate.

    PubMed

    Bow, Jong-Shing; Liou, Sz-Chian; Chen, San-Yuan

    2004-07-01

    A simple route for synthesizing nano-sized beta-tricalcium phosphate (beta-TCP) at room temperature has been developed in methanol solvent. The phase evolution from CaHPO4, intermediate amorphous calcium phosphate (ACP) phases (including ACP1 and ACP2 with different structures) to final beta-TCP with increasing aging time was observed. The formation of beta-TCP phase is favored due to the incorporation of carbonate which can suppress the transformation of ACP1 phase. High-resolution transmission electron microscopy image along [1-100] zone axis of beta-TCP reveals two types of lattice fringes (straight and wavy fringes) in beta-TCP structure due to structural imperfection. Furthermore, the observations of abnormal diffraction intensity and superlattice diffraction in selected-area diffraction patterns further confirm the chemical order-disorder characteristics in beta-TCP structure and can be used to elucidate the resorbability of beta-TCP in either in vivo or in vitro environment due to the imperfection in beta-TCP crystal.

  7. Collagen/Beta-Tricalcium Phosphate Based Synthetic Bone Grafts via Dehydrothermal Processing.

    PubMed

    Sarikaya, Burcu; Aydin, Halil Murat

    2015-01-01

    Millions of patients worldwide remain inadequately treated for bone defects related to factors such as disease or trauma. The drawbacks of metallic implant and autograft/allograft use have steered therapeutic approaches towards tissue engineering solutions involving tissue regeneration scaffolds. This study proposes a composite scaffold with properties tailored to address the macro- and microenvironmental conditions deemed necessary for successful regeneration of bone in defect areas. The biodegradable scaffold composed of porous beta-tricalcium phosphate particles and collagen type I fibers is prepared from a mixture of collagen type-I and β-tricalcium phosphate (β-TCP) particles via lyophilization, followed by dehydrothermal (DHT) processing. The effects of both sterilization via gamma radiation and the use of DHT processing to achieve cross-linking were investigated. The impact of the chosen fabrication methods on scaffold microstructure and β-TCP particle-collagen fiber combinations were analyzed using X-ray diffractometry (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and microcomputerized tomography (µ-CT). Electron spinning resonance (ESR) analysis was used to investigate free radicals formation following sterilization. Results revealed that the highly porous (65% porosity at an average of 100 µm pore size), mechanically adequate, and biocompatible scaffolds can be utilized for bone defect repairs. PMID:26504812

  8. Microstereolithography-Based Fabrication of Anatomically Shaped Beta-Tricalcium Phosphate Scaffolds for Bone Tissue Engineering.

    PubMed

    Du, Dajiang; Asaoka, Teruo; Shinohara, Makoto; Kageyama, Tomonori; Ushida, Takashi; Furukawa, Katsuko Sakai

    2015-01-01

    Porous ceramic scaffolds with shapes matching the bone defects may result in more efficient grafting and healing than the ones with simple geometries. Using computer-assisted microstereolithography (MSTL), we have developed a novel gelcasting indirect MSTL technology and successfully fabricated two scaffolds according to CT images of rabbit femur. Negative resin molds with outer 3D dimensions conforming to the femur and an internal structure consisting of stacked meshes with uniform interconnecting struts, 0.5 mm in diameter, were fabricated by MSTL. The second mold type was designed for cortical bone formation. A ceramic slurry of beta-tricalcium phosphate (β-TCP) with room temperature vulcanization (RTV) silicone as binder was cast into the molds. After the RTV silicone was completely cured, the composite was sintered at 1500°C for 5 h. Both gross anatomical shape and the interpenetrating internal network were preserved after sintering. Even cortical structure could be introduced into the customized scaffolds, which resulted in enhanced strength. Biocompatibility was confirmed by vital staining of rabbit bone marrow mesenchymal stromal cells cultured on the customized scaffolds for 5 days. This fabrication method could be useful for constructing bone substitutes specifically designed according to local anatomical defects. PMID:26504839

  9. Intramedullary anchoring strength of titanium rod with mixed beta-tricalcium phosphate and fibrin adhesive.

    PubMed

    Oyake, Yuichiro; Beppu, Moroe; Ishii, Shoji; Takagi, Masayuki; Takashi, Masahisa

    2002-01-01

    Histological and biomechanical studies were conducted in Japanese white rabbits to evaluate the effect of mixed beta-tricalcium phosphate (beta-TCP) and fibrin adhesive on bone formation around a titanium rod in femoral bone marrow. The animals received injections of fibrin adhesive with beta-TCP or hydroxyapatite into the femoral bone marrow from the distal end of the femur, where a titanium rod was inserted. Group I received fibrin adhesive only, group II received fibrin adhesive and hydroxyapatite (HA), and group III received fibrin adhesive and beta-TCP. On the examination of nondecalcified specimens, group III showed cross-bridging bone formation between beta-TCP particles at week 8, this being observed earlier than in group II. On mechanical evaluation, group III showed significant differences in maximum pull-out force at week 8, and in modulus of rigidity at week 24, compared with the other groups. On the examination of decalcified specimens, chronic inflammation was clearly identified in group I at week 8, and residual beta-TCP particles were found in group III at week 24. These results suggest that the mixture given to group III filled bone defects around the rod and promoted bone formation at a relatively early stage. Inflammation and delayed absorption of beta-TCP, which appeared to be a reaction of heterologous fibrins, caused delays in bone formation promoted by beta-TCP. Nevertheless, the use of fibrin adhesive appears to be a feasible method for loading powdered beta-TCP. PMID:11819144

  10. Synthesis and characterization of magnesium substituted biphasic mixtures of controlled hydroxyapatite/{beta}-tricalcium phosphate ratios

    SciTech Connect

    Kannan, S.; Lemos, I.A.F.; Rocha, J.H.G.; Ferreira, J.M.F. . E-mail: jmf@cv.ua.pt

    2005-10-15

    The present paper investigates the preparation of magnesium (Mg) substituted biphasic mixtures of different hydroxyapatite (HAP)/{beta}-tricalcium phosphate ({beta}-TCP) ratios through aqueous precipitation method. The concentrations of added magnesium (Mg) were varied with the calcium in order to obtain constant (Ca+Mg)/P ratios of 1.67 ranging from 1.62+0.05, 1.58+0.09 and 1.54+0.13, respectively. The as prepared powders were calcined at different temperatures to study the phase behaviour and thermal stability. The powders were characterized by the following analytical techniques: TG-DTA, X-ray diffraction and FT-IR. The results have shown that substitution of Mg in the calcium-deficient apatites resulted in the formation of biphasic mixtures of different HAP/{beta}-TCP ratios after heating above 700 deg. C. The ratios of the formation of phase mixtures were dependent on the calcium deficiency in the apatites with the higher deficiency having the strongest impact on the increased formation of {beta}-TCP and the substituted Mg was found to stabilize the {beta}-TCP phase. - Graphical abstract: Role of Mg in the behaviour of calcium-deficient apatites during calcination to form biphasic mixtures.

  11. Microstereolithography-Based Fabrication of Anatomically Shaped Beta-Tricalcium Phosphate Scaffolds for Bone Tissue Engineering

    PubMed Central

    Du, Dajiang; Asaoka, Teruo; Shinohara, Makoto; Kageyama, Tomonori; Ushida, Takashi; Furukawa, Katsuko Sakai

    2015-01-01

    Porous ceramic scaffolds with shapes matching the bone defects may result in more efficient grafting and healing than the ones with simple geometries. Using computer-assisted microstereolithography (MSTL), we have developed a novel gelcasting indirect MSTL technology and successfully fabricated two scaffolds according to CT images of rabbit femur. Negative resin molds with outer 3D dimensions conforming to the femur and an internal structure consisting of stacked meshes with uniform interconnecting struts, 0.5 mm in diameter, were fabricated by MSTL. The second mold type was designed for cortical bone formation. A ceramic slurry of beta-tricalcium phosphate (β-TCP) with room temperature vulcanization (RTV) silicone as binder was cast into the molds. After the RTV silicone was completely cured, the composite was sintered at 1500°C for 5 h. Both gross anatomical shape and the interpenetrating internal network were preserved after sintering. Even cortical structure could be introduced into the customized scaffolds, which resulted in enhanced strength. Biocompatibility was confirmed by vital staining of rabbit bone marrow mesenchymal stromal cells cultured on the customized scaffolds for 5 days. This fabrication method could be useful for constructing bone substitutes specifically designed according to local anatomical defects. PMID:26504839

  12. Evaluation of suitable porosity for sintered porous {beta}-tricalcium phosphate as a bone substitute

    SciTech Connect

    Park, Jin-Hong; Bae, Ji-Yong; Shim, Jaebum; Jeon, Insu

    2012-09-15

    Structural and mechanical characterization is performed for sintered porous beta tricalcium phosphate ({beta}-TCP) to determine the appropriate porosity for use as a bone substitute. Four different types of porous {beta}-TCP specimen with different porosities are fabricated through a sintering process. For structural characterization, scanning electron microscopy and a Microfocus X-ray computed tomography system are used to investigate the pore openings on the specimen's surface, pore size, pore distribution, and pore interconnections. Compression tests of the specimens are performed, and mechanical properties such as the elastic modulus and compressive strength are obtained. Also, the geometric shape and volume of the {beta}-TCP around the contact region of two pores, which need to be initially resolved after implantation in order to increase the size of the pore openings, are evaluated through simple calculations. The results show that porous {beta}-TCP with 42.1% porosity may be a suitable bone substitute candidate in terms of sustaining external loads, and inducing and cultivating bone cells. - Highlights: Black-Right-Pointing-Pointer Structural and mechanical characterization was performed for sintered porous {beta}-TCP specimens. Black-Right-Pointing-Pointer For structural characterization, SEM and Microfocus X-ray CT system were used. Black-Right-Pointing-Pointer For mechanical characterization, compression tests were performed. Black-Right-Pointing-Pointer Porous {beta}-TCP with 42.1% porosity may be a suitable bone substitute.

  13. Microstereolithography-Based Fabrication of Anatomically Shaped Beta-Tricalcium Phosphate Scaffolds for Bone Tissue Engineering.

    PubMed

    Du, Dajiang; Asaoka, Teruo; Shinohara, Makoto; Kageyama, Tomonori; Ushida, Takashi; Furukawa, Katsuko Sakai

    2015-01-01

    Porous ceramic scaffolds with shapes matching the bone defects may result in more efficient grafting and healing than the ones with simple geometries. Using computer-assisted microstereolithography (MSTL), we have developed a novel gelcasting indirect MSTL technology and successfully fabricated two scaffolds according to CT images of rabbit femur. Negative resin molds with outer 3D dimensions conforming to the femur and an internal structure consisting of stacked meshes with uniform interconnecting struts, 0.5 mm in diameter, were fabricated by MSTL. The second mold type was designed for cortical bone formation. A ceramic slurry of beta-tricalcium phosphate (β-TCP) with room temperature vulcanization (RTV) silicone as binder was cast into the molds. After the RTV silicone was completely cured, the composite was sintered at 1500°C for 5 h. Both gross anatomical shape and the interpenetrating internal network were preserved after sintering. Even cortical structure could be introduced into the customized scaffolds, which resulted in enhanced strength. Biocompatibility was confirmed by vital staining of rabbit bone marrow mesenchymal stromal cells cultured on the customized scaffolds for 5 days. This fabrication method could be useful for constructing bone substitutes specifically designed according to local anatomical defects.

  14. Novel bioactive composite bone cements based on the beta-tricalcium phosphate-monocalcium phosphate monohydrate composite cement system.

    PubMed

    Huan, Zhiguang; Chang, Jiang

    2009-05-01

    Bioactive composite bone cements were obtained by incorporation of tricalcium silicate (Ca3SiO5, C3S) into a brushite bone cement composed of beta-tricalcium phosphate [beta-Ca3(PO4)2, beta-TCP] and monocalcium phosphate monohydrate [Ca(H2PO4)2.H2O, MCPM], and the properties of the new cements were studied and compared with pure brushite cement. The results indicated that the injectability, setting time and short- and long-term mechanical strength of the material are higher than those of pure brushite cement, and the compressive strength of the TCP/MCPM/C3S composite paste increased with increasing aging time. Moreover, the TCP/MCPM/C3S specimens showed significantly improved in vitro bioactivity in simulated body fluid and similar degradability in phosphate-buffered saline as compared with brushite cement. Additionally, the reacted TCP/MCPM/C3S paste possesses the ability to stimulate osteoblast proliferation and promote osteoblastic differentiation of the bone marrow stromal cells. The results indicated that the TCP/MCPM/C3S cements may be used as a bioactive material for bone regeneration, and might have significant clinical advantage over the traditional beta-TCP/MCPM brushite cement.

  15. Coverage of gingival recession defects using acellular dermal matrix allograft with or without beta-tricalcium phosphate.

    PubMed

    Okubo, Nobuki; Fujita, Takahisa; Ishii, Yoshihito; Ota, Mikio; Shibukawa, Yoshihiro; Yamada, Satoru

    2013-01-01

    The aim of this study was to investigate the effect of beta-tricalcium phosphate (β-TCP) particles in combination with acellular dermal matrix (ADM) allograft in gingival recession. Experimental gingival recession defects were created in beagle dogs and randomly assigned to one of the following groups: ADM, ADM + β-TCP, or coronally positioned flap (CPF; control). Tissues were histologically examined at 4, 8, or 16 weeks following treatment. A greater thickness of gingiva was observed at the sites treated in both the ADM + β-TCP and ADM groups than in the CPF group. The ADM + β-TCP group showed a statistically significant increase in both new bone and cementum formations compared to the ADM group. The results suggest that the combination of β-TCP and ADM is more effective in promoting new bone and cementum formations than ADM graft alone. PMID:21862508

  16. In vitro degradation and fracture toughness of multilayered porous poly(propylene fumarate)/beta-tricalcium phosphate scaffolds.

    PubMed

    Wolfe, Michael S; Dean, David; Chen, Jeffrey E; Fisher, John P; Han, Seungho; Rimnac, Clare M; Mikos, Antonios G

    2002-07-01

    This study investigated the in vitro degradation of poly(propylene fumarate)/beta-tricalcium phosphate (PPF/beta-TCP) scaffolds in pH 7.4 phosphate-buffered saline at 37 degrees C. Scaffold design consisted of three layers: two solid layers about a central layer of porous PPF foam. Solid PPF with molecular weights of 810 and 1450 Da was crosslinked under UV light. PPF foam was prepared by a photocrosslinking, porogen-leaching method with an initial porogen content of 80 wt % and two sizes, 150-300 and 300-500 microm. Comparison of initial and residual weights demonstrated a 14.3 +/- 2.0% loss of mass at 3 weeks and a 16.6 +/- 1.8% loss of mass at 6 weeks. Observed pH values for all constructs remained stable (7.15-7.40) throughout the 3 to 6 weeks. Scanning electron micrographs of these scaffolds revealed some loss of foam material between 3 and 6 weeks; however, foam microarchitecture was intact. Solid PPF fracture toughness was tested for high and low molecular weight PPF, 0.376 +/- 0.004 and 0.134 +/- 0.015 MPa(m)1/2, respectively. These values are roughly one magnitude less than human cortical bone.

  17. Synthesis and characterization of sintered beta-tricalcium phosphate: A comparative study on the effect of preparation route.

    PubMed

    Ghosh, Rupita; Sarkar, Ritwik

    2016-10-01

    Beta-tricalcium phosphate (β-TCP) was prepared by three different routes namely, wet chemical coprecipitation, sol-gel and solution combustion synthesis. The synthesized powders were calcined at different temperatures and characterized for phase evolution study, thermal analysis, Fourier transform infrared (FTIR) spectroscopy, microstructural study for comparative analysis. The optimal thermal treatment required to prepare pure β-TCP powders was determined and after calcination of the synthesize powders prepared by different routes, pure β-TCP was obtained. The sintering temperature required to prepare fully dense β-TCP completely free from α-form was identified. The powders were then used to make dense and compact bodies sintered at 1200 and 1250°C. The sintering behaviour of the dense bodies was analysed using dilatometry, densification and microstructural study. It was found that the pellet prepared from powder synthesized via co-precipitation route attained maximum density compared to the pellets prepared from powders synthesized via sol-gel and solution combustion route. PMID:27287130

  18. In vitro studies of human and rat osteoclast activity on hydroxyapatite, beta-tricalcium phosphate, calcium carbonate.

    PubMed

    Monchau, F; Lefèvre, A; Descamps, M; Belquin-myrdycz, A; Laffargue, P; Hildebrand, H F

    2002-08-01

    Investigations on the ceramic degradation caused by osteoclasts are designed to assess osteoclast-ceramic interactions and to determine which ceramics are more suitable for use as bone substitute. This study investigated the resorptive activity of osteoclasts on ceramics presenting different solubility rates. Osteoclasts isolated from new-born rat and from human giant cell tumour were cultured on different bioceramics: hydroxyapatite (HA), beta-tricalcium phosphate (TCP) and calcium carbonate (calcite). Cytoskeletal was revealed by actin labelling and ceramic surfaces were observed by scanning electron microscopy (SEM). On all materials, the distribution of actin in typical ring was revealed. SEM examinations showed a clear difference in the shape and the depth of resorption lacunae on different ceramics. On pure HA, a superficial attack, clearly visible but very little extended. Numerous resorption lacunae, deep and well-delimited were observed on pure beta-TCP, but attacks less punctually were detected too. On pure calcite, an attack with form of spikes, very widespread but superficial was revealed. Degradation measurements revealed a significant increase of P release from the phosphocalcic ceramics and of Ca from all ceramics in the presence of osteoclasts. The both cell models found these characteristics, the rat osteoclasts were also an excellent model to study the ceramic resorption.

  19. Experimental study of bone formation around a titanium rod with beta-tricalcium phosphate and prostaglandin E2 receptor agonists.

    PubMed

    Masuzawa, Michinaga; Beppu, Moroe; Ishii, Shoji; Oyake, Yuichiro; Aoki, Haruhito; Takagi, Masayuki

    2005-05-01

    beta-Tricalcium phosphate (beta-TCP) is an excellent bone-filling material that is completely absorbed by the body and replaced by autologous bone. Unfortunately, its mechanical strength is low, rendering its application at loaded regions difficult. The purpose of this study is to evaluate the histological and mechanical effects of single and combined use of beta-TCP and EP4 agonist on bone formation around a titanium rod. beta-TCP was loaded into the femoral bone marrow from the distal end of the femur, where the titanium implants were inserted, and the animals received twice-daily subcutaneous injections of EP4 agonist. Group I received the rod only and was designated the control group; group II received EP4 agonist only; group III received beta-TCP only; and group IV received both beta-TCP and EP4 agonist. Examination of decalcified specimens revealed favorable bone formation in all treatment groups compared with that in group I, with the most active bone formation seen in group IV. Mechanical evaluation revealed significant differences in maximum pull-out force compared with group I at weeks 4 and 8. There were no differences between groups II and III at either week 4 or 8, but the values seen in group IV at weeks 4 and 8 were significantly higher compared with the other groups. Combined use of beta-TCP and EP4 agonist is expected to compensate for bone defects resulting from revision total joint arthroplasty and to achieve stability at an early stage. PMID:15928895

  20. Bone substitute: transforming beta-tricalcium phosphate porous scaffolds into monetite.

    PubMed

    Galea, Laëtitia G; Bohner, Marc; Lemaître, Jacques; Kohler, Thomas; Müller, Ralph

    2008-01-01

    The goal of the present study was to assess the possibility to change the composition of a calcium phosphate scaffold from a high-temperature phase to a phase only stable at or close to room temperature without macrostructural changes. For that purpose, macroporous beta-TCP scaffolds were converted into alpha-TCP by high-temperature thermal treatment and then dipped into a phosphoric acid solution to obtain a more acidic calcium phosphate phase called monetite or dicalcium phosphate (DCP; CaHPO4). Two different solid-to-liquid ratios (SLR: 0.067 and 0.200g/mL) and three different temperatures (T: 37, 60 and 80 degrees C) were used. The reaction was followed by measuring the change of sample size and weight, by determining the compositional changes by X-ray diffraction (Rietveld analysis), and by looking at the micro- and macrostructural changes by scanning electron microscopy and micro-computed tomography. The results revealed that the transformation proceeded faster at a higher temperature and a higher SLR value but was achieved within a few days in all cases. Morphologically, the porosity decreased by 10%, the pore size distribution became wider and the mean macro pore size was reduced from 0.28 to 0.19mm. The fastest conversion and the highest compressive strength (9MPa) were measured using an incubation temperature of 80 degrees C and an SLR value of 0.2g/mL.

  1. Stem cells in bone grafting: Trinity allograft with stem cells and collagen/beta-tricalcium phosphate with concentrated bone marrow aspirate.

    PubMed

    Guyton, Gregory P; Miller, Stuart D

    2010-12-01

    The orthopedic foot and ankle surgeon needs bone grafts in the clinical situation of fracture healing and in bone-fusion procedures. This article briefly outlines thought processes and techniques for 2 recent options for the surgeon. The Trinity product is a unique combination of allograft bone and allograft stem cells. The beta-tricalcium phosphate and collagen materials provide an excellent scaffold for bone growth; when combined with concentrated bone marrow aspirate, they also offer osteoconductive and osteoinductive as well as osteogenerative sources for new bone formation.

  2. Accelerated fracture healing in the geriatric, osteoporotic rat with recombinant human platelet-derived growth factor-BB and an injectable beta-tricalcium phosphate/collagen matrix.

    PubMed

    Hollinger, Jeffrey O; Onikepe, Andrew O; MacKrell, Jim; Einhorn, Thomas; Bradica, Gino; Lynch, Samuel; Hart, Charles E

    2008-01-01

    Aging and osteoporosis contribute to decreased bone mass and bone mineral density as well as compromised fracture healing rates and bone repair quality. Consequently, the purpose of this study was to determine if recombinant human platelet-derived growth factor-BB (rhPDGF-BB) delivered in an injectable beta-tricalcium phosphate/collagen matrix would enhance tibial fracture healing in geriatric (>2 years of age), osteoporotic rats. A total of 80 rats were divided equally among four groups: Fracture alone; Fracture plus matrix; Fracture plus matrix and either 0.3 mg/mL or 1.0 mg/mL rhPDGF-BB. At 3 and 5 weeks, rats were euthanized and treatment outcome was assessed histologically, radiographically, biomechanically, and by micro-CT. Results indicated rhPDGF-BB-treated fractures in osteoporotic, geriatric rats caused a statistically significant time-dependent increase in torsional strength 5 weeks after treatment. The healed fractures were equivalent in torsional strength to the contralateral, unoperated tibiae. Data from the study are the first, to our knowledge, to underscore rhPDGF-BB efficacy in an injectable beta-tricalcium phosphate/collagen matrix accelerated fracture repair in a geriatric, osteoporotic rat model.

  3. Synthesis of a novel beta-tricalcium phosphate/hydroxyapatite biphasic calcium phosphate containing niobium ions and evaluation of its osteogenic properties.

    PubMed

    Tamai, Masato; Isama, Kazuo; Nakaoka, Ryusuke; Tsuchiya, Toshie

    2007-01-01

    To promote the osteogenic properties of osteoblasts, we synthesized a hydroxyapatite (HAp) with beta-tricalcium phosphate (beta-TCP) biphasic calcium phosphate containing Nb ions (NbTCP/HAp). NbTCP/HAp was prepared by annealing precipitates obtained by coprecipitation of an aqueous solution of Ca(NO(3))(2) and a mixture of (NH(4))(2)HPO(4) and aqueous Nb solution. The precipitates can be regarded as a calcium-deficient HAp, the PO(4) sites of which are partly occupied by Nb ions. NbTCP/HAp was successfully synthesized by thermal decomposition of the precipitates. NbTCP/HAp enhanced the calcification of normal human osteoblasts (NHOst), and the amount of calcified tissue increased in proportion to the Nb ion concentration in the NbTCP/HAp. The alkaline phosphatase (ALP) activity of NHOst was also enhanced by NbTCP/HAp. Because Nb ions significantly enhance the ALP activity of NHOst, calcification by NbTCP/HAp is considered to be due to enhancement of ALP activity induced by Nb ions dissolved from NbTCP/HAp. These results indicate that NbTCP/HAp can be an effective bone repair material. PMID:17380293

  4. Effects of bioactive glass S53P4 or beta-tricalcium phosphate and bone morphogenetic protein-2 and bone morphogenetic protein-7 on osteogenic differentiation of human adipose stem cells

    PubMed Central

    Patrikoski, Mimmi; Juntunen, Miia; Kujala, Kasperi; Kääriäinen, Minna; Kuokkanen, Hannu; Sándor, George K; Vapaavuori, Outi; Suuronen, Riitta; Mannerström, Bettina; von Rechenberg, Brigitte; Miettinen, Susanna

    2012-01-01

    The effects of bioactive glass S53P4 or beta-tricalcium phosphate; and bone morphogenetic proteins bone morphogenetic protein-2, bone morphogenetic protein-7, or bone morphogenetic protein-2 + 7 on osteogenic differentiation of human adipose stem cells were compared in control medium, osteogenic medium, and bone morphogenetic protein-supplemented osteogenic medium to assess suitability for bone tissue engineering. Cell amount was evaluated with qDNA measurements; osteogenic differentiation using marker gene expression, alkaline phosphate activity, and angiogenic potential was measured by vascular endothelial growth factor expression. As compared to beta-tricalcium phosphate, cell amount was significantly greater for bioactive glass in control medium after 7 days and in osteogenic medium after 14 days, and alkaline phosphate activity was always significantly greater for bioactive glass in control medium. However, alkaline phosphate activity increased for beta-tricalcium phosphate and decreased for bioactive glass granules in osteogenic medium. For both biomaterials, bone morphogenetic protein supplementation decreased cell amount and osteogenic differentiation of human adipose stem cells, and vascular endothelial growth factor expressions correlated with cell amounts. Effects of culture medium on human adipose stem cells are biomaterial dependent; bioactive glass in control medium enhanced osteogenic differentiation most effectively. PMID:23316275

  5. The promotion of angiogenesis induced by three-dimensional porous beta-tricalcium phosphate scaffold with different interconnection sizes via activation of PI3K/Akt pathways

    PubMed Central

    Xiao, Xin; Wang, Wei; Liu, Dong; Zhang, Haoqiang; Gao, Peng; Geng, Lei; Yuan, Yulin; Lu, Jianxi; Wang, Zhen

    2015-01-01

    The porous architectural characteristics of biomaterials play an important role in scaffold revascularization. However, no consensus exists regarding optimal interconnection sizes for vascularization and its scaffold bioperformance with different interconnection sizes. Therefore, a series of disk-type beta-tricalcium phosphates with the same pore sizes and variable interconnections were produced to evaluate how the interconnection size influenced biomaterial vascularization in vitro and in vivo. We incubated human umbilical vein endothelial cells on scaffolds with interconnections of various sizes. Results showed that scaffolds with a 150 μm interconnection size ameliorated endothelial cell function evidenced by promoting cell adhesion and migration, increasing cell proliferation and enhancing expression of platelet-endothelial cell adhesion molecules and vascular endothelial growth factor. In vivo study was performed on rabbit implanted with scaffolds into the bone defect on femoral condyles. Implantation with scaffolds with 150 μm interconnection size significantly improved neovascularization as shown by micro-CT as compared to scaffolds with 100 and 120 μm interconnection sizes. Moreover, the aforementioned positive effects were abolished by blocking PI3K/Akt/eNOS pathway with LY-294002. Our study explicitly demonstrates that the scaffold with 150 μm interconnection size improves neovascularization via the PI3K/Akt pathway and provides a target for biomaterial inner structure modification to attain improved clinical performance in implant vascularization. PMID:25797242

  6. High porous titanium scaffolds showed higher compatibility than lower porous beta-tricalcium phosphate scaffolds for regulating human osteoblast and osteoclast differentiation.

    PubMed

    Hirota, Makoto; Hayakawa, Tohru; Shima, Takaki; Ametani, Akihiro; Tohnai, Iwai

    2015-04-01

    We compared osteoblast and osteoclast differentiation when using beta-tricalcium phosphate (βTCP) and titanium scaffolds by investigating human mesenchymal stem cells (hMSCs) and osteoclast progenitor cell activities. hMSCs were cultured for 7, 14, and 21days on titanium scaffolds with 60%, 73%, and 87% porosity and on βTCP scaffolds with 60% and 75% porosity. Human osteoclast progenitor cells were cultured with osteoblast for 14 and 21days on 87% titanium and 75% βTCP scaffolds. Viable cell numbers with 60% and 73% titanium were higher than with 87% titanium and βTCP scaffolds (P<0.05). An 87% titanium scaffold resulted in the highest osteocalcin production with calcification on day 14 (P<0.01) in titanium scaffolds. All titanium scaffolds resulted in higher osteocalcin production on days 7 and 14 compared to βTCP scaffolds (P<0.01). Osteoblasts cultured on 87% titanium scaffolds suppressed osteoclast differentiation on day 7 but enhanced osteoclast differentiation on day 14 compared to 75% βTCP scaffolds (P<0.01). These findings concluded that high porosity titanium scaffolds could enhance progression of hMSC/osteoblast differentiation and regulated osteoclast differentiation cooperating with osteoblast differentiation for calcification as compared with lower porous βTCP.

  7. The promotion of angiogenesis induced by three-dimensional porous beta-tricalcium phosphate scaffold with different interconnection sizes via activation of PI3K/Akt pathways.

    PubMed

    Xiao, Xin; Wang, Wei; Liu, Dong; Zhang, Haoqiang; Gao, Peng; Geng, Lei; Yuan, Yulin; Lu, Jianxi; Wang, Zhen

    2015-01-01

    The porous architectural characteristics of biomaterials play an important role in scaffold revascularization. However, no consensus exists regarding optimal interconnection sizes for vascularization and its scaffold bioperformance with different interconnection sizes. Therefore, a series of disk-type beta-tricalcium phosphates with the same pore sizes and variable interconnections were produced to evaluate how the interconnection size influenced biomaterial vascularization in vitro and in vivo. We incubated human umbilical vein endothelial cells on scaffolds with interconnections of various sizes. Results showed that scaffolds with a 150 μm interconnection size ameliorated endothelial cell function evidenced by promoting cell adhesion and migration, increasing cell proliferation and enhancing expression of platelet-endothelial cell adhesion molecules and vascular endothelial growth factor. In vivo study was performed on rabbit implanted with scaffolds into the bone defect on femoral condyles. Implantation with scaffolds with 150 μm interconnection size significantly improved neovascularization as shown by micro-CT as compared to scaffolds with 100 and 120 μm interconnection sizes. Moreover, the aforementioned positive effects were abolished by blocking PI3K/Akt/eNOS pathway with LY-294002. Our study explicitly demonstrates that the scaffold with 150 μm interconnection size improves neovascularization via the PI3K/Akt pathway and provides a target for biomaterial inner structure modification to attain improved clinical performance in implant vascularization.

  8. A Comparison of the Process of Remodeling of Hydroxyapatite/Poly-D/L-Lactide and Beta-Tricalcium Phosphate in a Loading Site

    PubMed Central

    Akagi, Hiroyuki; Ochi, Hiroki; Soeta, Satoshi; Kanno, Nobuo; Yoshihara, Megumi; Okazaki, Kenshi; Yogo, Takuya; Harada, Yasuji; Amasaki, Hajime; Hara, Yasushi

    2015-01-01

    Currently, the most commonly used bioresorbable scaffold is made of beta-tricalcium phosphate (β-TCP); it is hoped that scaffolds made of a mixture of hydroxyapatite (HA) and poly-D/L-lactide (PDLLA) will be able to act as novel bioresorbable scaffolds. The aim of this study was to evaluate the utility of a HA/PDLLA scaffold compared to β-TCP, at a loading site. Dogs underwent surgery to replace a section of tibial bone with a bioresorbable scaffold. After the follow-up period, the scaffold was subjected to histological analysis. The HA/PDLLA scaffold showed similar bone formation and superior cell and tissue infiltration compared to the β-TCP scaffold, as seen after Villanueva Goldner staining. Moreover, silver staining and immunohistochemistry for Von Willebrand factor and cathepsin K demonstrated better cell infiltration in the HA/PDLLA scaffold. The fibrous tissue and cells that had infiltrated into the HA/PDLLA scaffold tested positive for collagen type I and RUNX2, respectively, indicating that the tissue and cells that had infiltrated into the HA/PDLLA scaffold had the potential to differentiate into bone. The HA/PDLLA scaffold is therefore likely to find clinical application as a new bioresorbable scaffold. PMID:26504825

  9. Development of a bioresorbable self-hardening bone adhesive based on a composite consisting of polylactide methacrylates and beta-tricalcium phosphate.

    PubMed

    Heiss, C; Kraus, R; Peters, F; Henn, W; Schnabelrauch, M; Berg, A; Pautzsch, T; Weisser, J; Schnettler, R

    2009-07-01

    In this work, a novel bioresorbable bone adhesive based on radically polymerizable polylactide with methacrylate endgroups known from polymethylmethacrylate (PMMA) cements and varying amounts of bioresorbable/biodegradable lactide moieties was developed. The swelling and degradation properties as well as the hardening time, viscosity, and adhesion properties (tension and shear resistance) were subsequently measured in vitro and optimized. For a broad use in surgery the handling properties, the shelf life and the storage temperature are important issues. The finally developed material consists of three substances that have to be mixed to start the reaction: a highly viscous mixture of oligomers and two beta-tricalcium phosphate (beta-TCP, Cerasorb) powders with the radical starter and the promoter. The material has a processing time of 2 min and is completely cured after another minute. The tension and shear resistance of the material is 3.1-13.9 MPa that will decrease by storing the substance in a humid atmosphere. Degradation experiments showed a mass loss of 20-35% during the first 5 weeks. Tests with MC3T3-E1 cells showed an increase of the alkaline phosphatase activity over a period of 14 days. The mechanical and handling properties and the in vitro data are showing a promising biomaterial for bone regeneration.

  10. Effect of reinforcement particle size on in vitro behavior of beta-tricalcium phosphate-reinforced high-density polyethylene: a novel orthopedic composite.

    PubMed

    Homaeigohar, S S H; Shokrgozar, M A; Javadpour, J; Khavandi, A; Sadi, A Yari

    2006-07-01

    Beta-tricalcium phosphate-reinforced high-density polyethylene (beta-TCP/HDPE) is a new biomaterial, which was made to simulate bone composition and study its capacity to act like bony tissues. This material was produced by replacing mineral component and collagen soft tissue of bone with beta-TCP and HDPE, respectively. The biocompatibility of composite samples with different volume fractions of TCP (20, 30, and 40 vol %) and two different particle sizes (80-100 and 120-140 mesh size) was examined in vitro using the osteoblast cell line G-292 by proliferation, alkaline phosphatase (ALP) production, and cell adhesion assays. Cell-material interaction on the surface of the composites was observed by scanning electron microscopy (SEM). The effect of beta-TCP particle size on behavior of the osteoblast cell line was compared between two groups of the composite samples containing smaller and larger reinforcement particle sizes as well as with those of a negative control. In general, results showed that the composite samples containing larger particles supported a higher rate of proliferation and ALP production by osteoblast cells after 3, 7, and 14 days of incubation compared to the composite samples with smaller particle size and control. Furthermore, more cells were attached to the surface of composite samples containing larger particle size when compared to the smaller particle size composites (p<0.05). This number was nearly equal with numbers adhered on negative control [tissue culture polystyrene (TPS)] and significantly higher in comparison with composite control [polyethylene (PE)] (p<0.05). Adhered cells presented a normal morphology by SEM and many of the cells were seen to be undergoing cell division. These findings indicate that beta-TCP/HDPE composites are biocompatible, nontoxic, and in some cases, act to stimulate proliferation of the cells, ALP production, and cell adhesion when compared to the control counterparts. Furthermore, beta-TCP/HDPE samples

  11. Effects of concomitant use of fibroblast growth factor (FGF)-2 with beta-tricalcium phosphate ({beta}-TCP) on the beagle dog 1-wall periodontal defect model

    SciTech Connect

    Anzai, Jun; Kitamura, Masahiro; Nozaki, Takenori; Nagayasu, Toshie; Terashima, Akio; Asano, Taiji; Murakami, Shinya

    2010-12-17

    Research highlights: {yields} Concomitant use of FGF-2 and {beta}-TCP (an osteo-conductive scaffold) significantly promotes periodontal regeneration in the severe periodontitis model (1-wall defect model) of beagle dog. {yields} FGF-2 enhanced new bone formation via {beta}-TCP at the defects. {yields} In particular, FGF-2 dramatically regenerated new periodontal ligament and cementum formations at the defects, that is one of the most important healing outcomes during the process of periodontal regeneration. {yields} Epithelial downgrowth (undesirable wound healing) was decreased by administration of FGF-2. {yields} This manuscript indicates for the first time that concomitant use of FGF-2 and {beta}-TCP is efficacious in regenerating periodontal tissue following severe destruction of the tissue by progression of periodontitis. -- Abstract: The effects of concomitant use of fibroblast growth factor-2 (FGF-2) and beta-tricalcium phosphate ({beta}-TCP) on periodontal regeneration were investigated in the beagle dog 1-wall periodontal defect model. One-wall periodontal defects were created in the mesial portion of both sides of the mandibular first molars, and 0.3% FGF-2 plus {beta}-TCP or {beta}-TCP alone was administered. Radiographic evaluation was performed at 0, 3, and 6 weeks. At 6 weeks, the periodontium with the defect site was removed and histologically analyzed. Radiographic findings showed that co-administration of FGF-2 significantly increased bone mineral contents of the defect sites compared with {beta}-TCP alone. Histologic analysis revealed that the length of the regenerated periodontal ligament, the cementum, distance to the junctional epithelium, new bone height, and area of newly formed bone were significantly increased in the FGF-2 group. No abnormal inflammatory response or ankylosis was observed in either group. These findings indicate the efficacy of concomitant use of FGF-2 and {beta}-TCP as an osteoconductive material for periodontal

  12. Ectopic bone regeneration by human bone marrow mononucleated cells, undifferentiated and osteogenically differentiated bone marrow mesenchymal stem cells in beta-tricalcium phosphate scaffolds.

    PubMed

    Ye, Xinhai; Yin, Xiaofan; Yang, Dawei; Tan, Jian; Liu, Guangpeng

    2012-07-01

    Tissue engineering approaches using the combination of porous ceramics and bone marrow mesenchymal stem cells (BMSCs) represent a promising bone substitute for repairing large bone defects. Nevertheless, optimal conditions for constructing tissue-engineered bone have yet to be determined. It remains unclear if transplantation of predifferentiated BMSCs is superior to undifferentiated BMSCs or freshly isolated bone marrow mononucleated cells (BMNCs) in terms of new bone formation in vivo. The aim of this study was to investigate the effect of in vitro osteogenic differentiation (β-glycerophosphate, dexamethasone, and l-ascorbic acid) of human BMSCs on the capability to form tissue-engineered bone in unloaded conditions after subcutaneous implantation in nude mice. After isolation from human bone marrow aspirates, BMNCs were divided into three parts: one part was seeded onto porous beta-tricalcium phosphate ceramics immediately and transplanted in a heterotopic nude mice model; two parts were expanded in vitro to passage 2 before cell seeding and in vivo transplantation, either under osteogenic conditions or not. Animals were sacrificed for micro-CT and histological evaluation at 4, 8, 12, 16, and 20 weeks postimplantation. The results showed that BMSCs differentiated into osteo-progenitor cells after induction, as evidenced by the altered cell morphology and elevated alkaline phosphatase activity and calcium deposition, but their clonogenicity, proliferating rate, and seeding efficacy were not significantly affected by osteogenic differentiation, compared with undifferentiated cells. Extensive new bone formed in the pores of all the scaffolds seeded with predifferentiated BMSCs at 4 weeks after implantation, and maintained for 20 weeks. On the contrary, scaffolds containing undifferentiated BMSCs revealed limited bone formation only in 1 out of 6 cases at 8 weeks, and maintained for 4 weeks. For scaffolds with BMNCs, woven bone was observed sporadically only in one

  13. Beta-tricalcium phosphate granules improve osteogenesis in vitro and establish innovative osteo-regenerators for bone tissue engineering in vivo

    PubMed Central

    Gao, Peng; Zhang, Haoqiang; Liu, Yun; Fan, Bo; Li, Xiaokang; Xiao, Xin; Lan, Pingheng; Li, Minghui; Geng, Lei; Liu, Dong; Yuan, Yulin; Lian, Qin; Lu, Jianxi; Guo, Zheng; Wang, Zhen

    2016-01-01

    The drawbacks of traditional bone-defect treatments have prompted the exploration of bone tissue engineering. This study aimed to explore suitable β-tricalcium phosphate (β-TCP) granules for bone regeneration and identify an efficient method to establish β-TCP-based osteo-regenerators. β-TCP granules with diameters of 1 mm and 1–2.5 mm were evaluated in vitro. The β-TCP granules with superior osteogenic properties were used to establish in vivo bioreactors, referred to as osteo-regenerators, which were fabricated using two different methods. Improved proliferation of bone mesenchymal stem cells (BMSCs), glucose consumption and ALP activity were observed for 1–2.5 mm β-TCP compared with 1-mm granules (P < 0.05). In addition, BMSCs incubated with 1–2.5 mm β-TCP expressed significantly higher levels of the genes for runt-related transcription factor-2, alkaline phosphatase, osteocalcin, osteopontin, and collagen type-1 and the osteogenesis-related proteins alkaline phosphatase, collagen type-1 and runt-related transcription factor-2 compared with BMSCs incubated with 1 mm β-TCP (P < 0.05). Fluorochrome labelling, micro-computed tomography and histological staining analyses indicated that the osteo-regenerator with two holes perforating the femur promoted significantly greater bone regeneration compared with the osteo-regenerator with a periosteum incision (P < 0.05). This study provides an alternative to biofunctionalized bioreactors that exhibits improved osteogenesis. PMID:27000963

  14. The use of Reamer Irrigator Aspirator (RIA) autograft harvest in the treatment of critical-sized iliac wing defects in sheep: investigation of dexamethasone and beta-tricalcium phosphate augmentation.

    PubMed

    Beck, Aswin; Nehrbass, Dirk; Stoddart, Martin J; Schiuma, Damiano; Green, Jim; Lansdowne, Jennifer L; Richards, R Geoff; Bouré, Ludovic P

    2013-04-01

    Bone grafts are commonly used for the treatment of segmental bone defects and fracture non-unions. Recently, osseous particles obtained during intermedullary canal reaming (using a Reamer-Irrigator-Aspirator (RIA) device) have been evaluated as graft material during in vitro and clinical studies. The aim of this study was to evaluate and quantify new bone formation after implantation of bone graft material obtained after reaming of the tibia in a bilateral critical-sized iliac wing defect in sheep and to investigate the effect of the augmentation of this graft. A reamer bone graft alone, or after short term incubation in a dexamethasone enriched solution, and a reamer graft collected using beta-tricalcium phosphate (β-TCP) granules in the filter of the RIA collection device were compared to autologous iliac wing graft. In addition, reamer graft was combined with the cellular fraction collected from the irrigation fluid with and without short-term incubation in a dexamethasone enriched solution. It was hypothesized that the amount of physical bone in the reamer bone graft groups would be higher than the amount in the autologous iliac wing graft group and that augmentation of a reamer bone graft would increase bone formation. Three months after implantation, the amount of new bone formation (as percentage of the total defect volume) in the defects was evaluated ex-vivo by means of micro-CT and histomorphometry. The mean amount of bone in the autologous iliac wing graft group was 17.7% and 16.8% for micro-CT and histomorphometry, respectively. The mean amount of bone in all reamer graft groups ranged between 20.4-29.2% (micro-CT) and 17.0-25.4% (histomorphometry). Reamer graft collected using β-TCP granules (29.2±1.7%) in the filter produced a significantly higher amount of bone in comparison to an autologous iliac wing graft evaluated by micro-CT. RIA bone grafts added a small increase in bone volume to the 3month graft volume in this preclinical sheep model. The

  15. Stem Cells Cultured on Beta Tricalcium Phosphate (β-TCP) in Combination with Recombinant Human Platelet-Derived Growth Factor - BB (rh-PDGF-BB) for the Treatment of Human Infrabony Defects.

    PubMed

    Dhote, Roshani; Charde, Priti; Bhongade, Manohar; Rao, Jyotsana

    2015-01-01

    Knowledge gained from the field of tissue engineering, helped to develop a biological substitute that promotes tissue regeneration. The usual biological substitute consists of stem cells, growth factors and an appropriate scaffold. The present randomized controlled clinical and radiographic study was undertaken to evaluate the effectiveness of mesenchymal stem cells cultured on beta tricalcium phosphate (β-TCP) in combination with rh-PDGF-BB in treatment of infrabony defect in humans. A total of 24 infrabony defects in 14 systemically healthy patients were selected for the present study. The selected defects exhibited a probing pocket depth (PPD) of ≥ 5 mm and depth of infrabony component ≥ 3 mm as assessed by clinical and radiographic measurements and later confirmed by intrasurgical measurement. Baseline measurements included were Plaque Index (PI), Papillary Bleeding Index (PBI), Probing Pocket Depth (PPD), Relative gingival marginal level (RGML), Relative Clinical Attachment Level (R-CAL) and Radiographic Defect Depth (DD) and linear bone growth (LBG). 6 weeks after initial therapy, the defects were randomly assigned to either test group or control group. The control group was treated by an open flap debridement (OFD) only, while the test group was treated by a Stem cells cultured on β-TCP in combination with rh-PDGF-BB. All the measurements recorded preoperatively were repeated at 6 months after the surgery. The efficacy of each treatment modality was investigated through statistical analysis. Mean probing pocket depth reduction was significantly greater in test group (4.50 ± 1.08 mm) compared to the OFD group (3.50 ± 0.90 mm). Mean gains in clinical attachment level was 3.91 ± 1.37 mm in the test group and 2.08 ± 0.90 mm in the control group. The mean increase in gingival recession (GR) was less in test group (0.58 ± 0.79 mm) compared to OFD group (1.4 ± 0.66 mm). Radiographic defect depth reduction was greater in the test group (3.50 ± 0.67 mm

  16. Guided bone regeneration in standardized calvarial defects using beta-tricalcium phosphate and collagen membrane: a real-time in vivo micro-computed tomographic experiment in rats.

    PubMed

    Ramalingam, Sundar; Al-Rasheed, Abdulaziz; ArRejaie, Aws; Nooh, Nasser; Al-Kindi, Mohammed; Al-Hezaimi, Khalid

    2016-05-01

    Guided bone regeneration (GBR) procedures using graft materials have been used for reconstruction of osseous defects. The aim of the present in vivo micro-computed tomographic (µCT) and histologic study was to assess in real time the bone regeneration at GBR sites in standardized experimental calvarial defects (diameter 3.3 mm) using β-tricalcium phosphate (β-TCP) with and without collagen membrane (CM). A single full-thickness calvarial defect was created on the left parietal bone in young female Wistar albino rats (n = 30) weighing approximately 300 g and aged about 6 weeks. The animals were randomly divided into three groups for treatment, based on calvarial defect filling material: (1) control group (n = 10); (2) β-TCP + CM group (n = 10); (3) β-TCP group (n = 10). Real-time in vivo µCT analyses were performed immediately after surgery and at 2, 4, 6 and 10 weeks to determine the volume and mineral density of the newly formed bone (BVNFB, MDNFB) and remaining β-TCP particles (VRBP, MDRBP). The animals were killed at 10 weeks and calvarial specimens were evaluated histologically. In the control group, MDNFB increased significantly at 6 weeks (0.32 ± 0.002 g/mm(3), P < 0.01) compared to that at baseline. In β-TCP + CM group, BVNFB (1.10 ± 0.12 mm(3), P < 0.01) and MDNFB (0.13 ± 0.02 g/mm(3), P < 0.01) significantly increased at the 4th week than baseline. In the β-TCP group, BVNFB (1.13 ± 0.12 mm(3), P < 0.01) and MDNFB (0.14 ± 0.01 g/mm(3), P < 0.01) significantly increased at 6 weeks compared to that at baseline. Significant reduction in VRBP was neither seen in the β-TCP + CM group nor in the β-TCP group. While in the β-TCP + CM group MDRBP was reduced significantly at 6 weeks (0.44 ± 0.9 g/mm(3), P < 0.01) from baseline (0.98 ± 0.03 g/mm(3)), similar significant reduction in MDRBP from baseline (0.92 ± 0.07 g/mm(3)) was seen only at 10 weeks (0.45 ± 0.06 g/mm(3), P < 0.05) in the β-TCP group. Histologic findings at 10 weeks revealed

  17. A minimum 2-year comparative study of autologous cancellous bone grafting versus beta-tricalcium phosphate in anterior cervical discectomy and fusion using a rectangular titanium stand-alone cage.

    PubMed

    Yamagata, Toru; Naito, Kentaro; Arima, Hironori; Yoshimura, Masaki; Ohata, Kenji; Takami, Toshihiro

    2016-07-01

    Although titanium stand-alone cages are commonly used in anterior cervical discectomy and fusion (ACDF), there are several concerns such as cage subsidence after surgery. The efficacy of β-tricalcium phosphate (β-TCP) granules as a packing material in 1- or 2-level ACDF using a rectangular titanium stand-alone cage is not fully understood. The purpose of this study is to investigate the validity of rectangular titanium stand-alone cages in 1- and 2-level ACDF with β-TCP. This retrospective study included 55 consecutive patients who underwent ACDF with autologous iliac cancellous bone grafting and 45 consecutive patients with β-TCP grafting. All patients completed at least 2-year postoperative follow-up. Univariate and multivariate analyses were performed to examine the associations between study variables and nonunion after surgery. Significant neurological recovery after surgery was obtained in both groups. Cage subsidence was noted in 14 of 72 cages (19.4 %) in the autograft group and 12 of 64 cages (18.8 %) in the β-TCP group. A total of 66 cages (91.7 %) in the autograft group showed osseous or partial union, and 58 cages (90.6 %) in the β-TCP group showed osseous or partial union by 2 years after surgery. There were no significant differences in cage subsidence and the bony fusion rate between the two groups. Multivariate analysis using a logistic regression model showed that fusion level at C6/7, 2-level fusion, and cage subsidence of grades 2-3 were significantly associated with nonunion at 2 years after surgery. Although an acceptable surgical outcome with negligible complication appears to justify the use of rectangular titanium stand-alone cages in 1- and 2-level ACDF with β-TCP, cage subsidence after surgery needs to be avoided to achieve acceptable bony fusion at the fused segments. Fusion level at C6/7 or 2-level fusion may be another risk factor of nonunion. PMID:27098659

  18. A minimum 2-year comparative study of autologous cancellous bone grafting versus beta-tricalcium phosphate in anterior cervical discectomy and fusion using a rectangular titanium stand-alone cage.

    PubMed

    Yamagata, Toru; Naito, Kentaro; Arima, Hironori; Yoshimura, Masaki; Ohata, Kenji; Takami, Toshihiro

    2016-07-01

    Although titanium stand-alone cages are commonly used in anterior cervical discectomy and fusion (ACDF), there are several concerns such as cage subsidence after surgery. The efficacy of β-tricalcium phosphate (β-TCP) granules as a packing material in 1- or 2-level ACDF using a rectangular titanium stand-alone cage is not fully understood. The purpose of this study is to investigate the validity of rectangular titanium stand-alone cages in 1- and 2-level ACDF with β-TCP. This retrospective study included 55 consecutive patients who underwent ACDF with autologous iliac cancellous bone grafting and 45 consecutive patients with β-TCP grafting. All patients completed at least 2-year postoperative follow-up. Univariate and multivariate analyses were performed to examine the associations between study variables and nonunion after surgery. Significant neurological recovery after surgery was obtained in both groups. Cage subsidence was noted in 14 of 72 cages (19.4 %) in the autograft group and 12 of 64 cages (18.8 %) in the β-TCP group. A total of 66 cages (91.7 %) in the autograft group showed osseous or partial union, and 58 cages (90.6 %) in the β-TCP group showed osseous or partial union by 2 years after surgery. There were no significant differences in cage subsidence and the bony fusion rate between the two groups. Multivariate analysis using a logistic regression model showed that fusion level at C6/7, 2-level fusion, and cage subsidence of grades 2-3 were significantly associated with nonunion at 2 years after surgery. Although an acceptable surgical outcome with negligible complication appears to justify the use of rectangular titanium stand-alone cages in 1- and 2-level ACDF with β-TCP, cage subsidence after surgery needs to be avoided to achieve acceptable bony fusion at the fused segments. Fusion level at C6/7 or 2-level fusion may be another risk factor of nonunion.

  19. Release, biological potency, and biochemical integrity of recombinant human platelet-derived growth factor-BB (rhPDGF-BB) combined with Augment(TM) Bone Graft or GEM 21S beta-tricalcium phosphate (beta-TCP).

    PubMed

    Young, C S; Ladd, P A; Browning, C F; Thompson, A; Bonomo, J; Shockley, K; Hart, C E

    2009-12-16

    Over 10 million surgical procedures are performed annually in the United States to treat musculoskeletal injuries, and a significant portion of these involve orthopedic bone grafting. The goals of the study were to evaluate the in vitro and in vivo release kinetics, biological potency and biochemical integrity of rhPDGF-BB combined with large (1000-2000 microm) and small (250-1000 microm) beta-TCP particles. Recombinant human platelet-derived growth factor B homodimer (rhPDGF-BB) is a protein growth factor under development as a therapeutic for accelerating bone healing. Release of the protein was monitored in vitro by ELISA, and in vivo by measurement of radioactive rhPDGF-BB implanted in rat calvarial defects. Biological activity was measured using a cell-based bioassay, and biochemical integrity was determined by SDS-PAGE and high pressure size exclusion chromatography (HPSEC). Release of rhPDGF-BB occurred rapidly from beta-TCP both in vitro and in vivo. Almost 100% of the rhPDGF-BB was recovered from large and small beta-TCP after 90 min in vitro. Approximately 90% of the rhPDGF-BB was depleted from calvarial defect sites within 72 h of implantation. RhPDGF-BB retained 100% of its biological potency compared to reference standard rhPDGF-BB, manifested as a single band at ~30 kDa by SDS-PAGE and a single peak eluted after 13 min by HPSEC following release from beta-TCP. RhPDGF-BB is rapidly released from large and small beta-TCP particles and is biochemically unaltered following release. PMID:19577598

  20. Reactive calcium-phosphate-containing poly(ester-co-ether) methacrylate bone adhesives: chemical, mechanical and biological considerations.

    PubMed

    Zhao, Xin; Olsen, Irwin; Li, Haoying; Gellynck, Kris; Buxton, Paul G; Knowles, Jonathan C; Salih, Vehid; Young, Anne M

    2010-03-01

    A poly(propylene glycol-co-lactide) dimethacrylate adhesive with monocalcium phosphate monohydrate (MCPM)/beta-tricalcium phosphate (beta-TCP) fillers in various levels has been investigated. Water sorption by the photo-polymerized materials catalyzed varying filler conversion to dicalcium phosphate (DCP). Polymer modulus was found to be enhanced upon raising total calcium phosphate content. With greater DCP levels, faster release of phosphate and calcium ions and improved buffering of polymer degradation products were observed. This could reduce the likelihood of pH-catalyzed bulk degradation and localized acid production and thereby may prevent adverse biological responses. Bone-like MG-63 cells were found to attach, spread and have normal morphology on both the polymer and composite surfaces. Moreover, composites implanted into chick embryo femurs became closely apposed to the host tissue and did not appear to induce adverse immunological reaction. The above results suggest that the new composite materials hold promise as clinical effective bone adhesives.

  1. Tethering of Epidermal Growth Factor (EGF) to Beta Tricalcium Phosphate (βTCP) via Fusion to a High Affinity, Multimeric βTCP-Binding Peptide: Effects on Human Multipotent Stromal Cells/Connective Tissue Progenitors

    PubMed Central

    Stockdale, Linda; Saini, Sunil; Lee, Richard T.; Griffith, Linda G.

    2015-01-01

    Transplantation of freshly-aspirated autologous bone marrow, together with a scaffold, is a promising clinical alternative to harvest and transplantation of autologous bone for treatment of large defects. However, survival proliferation, and osteogenic differentiation of the marrow-resident stem and progenitor cells with osteogenic potential can be limited in large defects by the inflammatory microenvironment. Previous studies using EGF tethered to synthetic polymer substrates have demonstrated that surface-tethered EGF can protect human bone marrow-derived osteogenic stem and progenitor cells from pro-death inflammatory cues and enhance their proliferation without detriment to subsequent osteogenic differentiation. The objective of this study was to identify a facile means of tethering EGF to clinically-relevant βTCP scaffolds and to demonstrate the bioactivity of EGF tethered to βTCP using stimulation of the proliferative response of human bone-marrow derived mesenchymal stem cells (hBMSC) as a phenotypic metric. We used a phage display library and panned against βTCP and composites of βTCP with a degradable polyester biomaterial, together with orthogonal blocking schemes, to identify a 12-amino acid consensus binding peptide sequence, LLADTTHHRPWT, with high affinity for βTCP. When a single copy of this βTCP-binding peptide sequence was fused to EGF via a flexible peptide tether domain and expressed recombinantly in E. coli together with a maltose-binding domain to aid purification, the resulting fusion protein exhibited modest affinity for βTCP. However, a fusion protein containing a linear concatamer containing 10 repeats of the binding motif the resulting fusion protein showed high affinity stable binding to βTCP, with only 25% of the protein released after 7 days at 37oC. The fusion protein was bioactive, as assessed by its abilities to activate kinase signaling pathways downstream of the EGF receptor when presented in soluble form, and to enhance the proliferation of hBMSC when presented in tethered form on commercial βTCP bone regeneration scaffolds. PMID:26121597

  2. Bacterial biosynthesis of a calcium phosphate bone-substitute material.

    PubMed

    Thackray, Aniac C; Sammons, Rachel L; Macaskie, Lynne E; Yong, Ping; Lugg, Harriet; Marquis, Peter M

    2004-04-01

    A species of Serratia bacteria produces nano-crystalline hydroxyapatite (HA) crystals by use of a cell-bound phosphatase enzyme, located both periplasmically and within extracellular polymeric materials. The enzyme functions in resting cells by cleaving glycerol-2-phosphate (G-2-P) to liberate free phosphate ions which combine with calcium in solution to produce a cell-bound calcium phosphate material. Bacteria grown as a biofilm on polyurethane reticulated foam cubes were challenged with calcium and G-2-P in a bioreactor to produce a 3-D porous bone-substitute material. The scaffold has 1 mm macropores and 1 microm micropores. XRD showed the crystallites to be 25-28 nm in size, resembling HA before sintering and beta-tricalcium phosphate (beta-TCP, whitlockite) after. When biofilm was grown on titanium discs and challenged with calcium and G-2-P, a calcium phosphate layer formed on the discs. Biomineralisation is therefore a potential route to production of precursor nanophase HA, which has the potential to improve strength. The scaffold material produced by this method could be used as a bone-filler or as an alternative method for coating implants with a layer of HA.

  3. Bone Regeneration of Rat Tibial Defect by Zinc-Tricalcium Phosphate (Zn-TCP) Synthesized from Porous Foraminifera Carbonate Macrospheres

    PubMed Central

    Chou, Joshua; Hao, Jia; Kuroda, Shinji; Bishop, David; Ben-Nissan, Besim; Milthorpe, Bruce; Otsuka, Makoto

    2013-01-01

    Foraminifera carbonate exoskeleton was hydrothermally converted to biocompatible and biodegradable zinc-tricalcium phosphate (Zn-TCP) as an alternative biomimetic material for bone fracture repair. Zn-TCP samples implanted in a rat tibial defect model for eight weeks were compared with unfilled defect and beta-tricalcium phosphate showing accelerated bone regeneration compared with the control groups, with statistically significant bone mineral density and bone mineral content growth. CT images of the defect showed restoration of cancellous bone in Zn-TCP and only minimal growth in control group. Histological slices reveal bone in-growth within the pores and porous chamber of the material detailing good bone-material integration with the presence of blood vessels. These results exhibit the future potential of biomimetic Zn-TCP as bone grafts for bone fracture repair. PMID:24351911

  4. In vitro aging of a calcium phosphate cement.

    PubMed

    Bohner, M; Merkle, H P; Lemaître, J

    2000-03-01

    Cement samples made of beta-tricalcium phoshate (beta-TCP), phosphoric acid (PA) and water mixtures were incubated in several aqueous solutions to determine their stability over time. The effects of the cement composition and the incubating temperature were investigated in more detail. The cement samples contained mostly dicalcium phosphate dihydrate (DCPD) and remnants of beta-TCP crystals. Depending on the initial cement composition, a certain amount of dicalcium phosphate (DCP) crystals were formed. The larger the initial PA concentration, the larger the DCP amount. After setting, the cement composition was stable for at least 16 days up to 60 degrees C. Above that temperature, the DCPD crystals decomposed into DCP crystals. The latter reaction provoked a decrease of the pH of the incubation solution, phenomenon expected for a cement sample containing an excess of PA. As the cement samples contained an excess of beta-TCP, it was postulated that beta-TCP crystals became so covered by DCP or DCPD crystals during setting that the setting reaction was stopped prematurely. The latter phenomenon gave a good explanation for the low pH values measured in the incubation solutions.

  5. Reinforcement of freeze-dried chitosan scaffolds with multiphasic calcium phosphate short fibers.

    PubMed

    Mohammadi, Zahra; Mesgar, Abdorreza Sheikh-Mehdi; Rasouli-Disfani, Fariba

    2016-08-01

    The composite scaffolds of the chitosan and multiphasic calcium phosphate (HW) short fibers were prepared by freeze drying and characterized by X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM and FE-SEM). The mechanical properties of the scaffolds were assessed by compression test. The incorporation of HW fibers consisting three phases of hydroxyapatite (HA), beta-tricalcium phosphate (β-TCP) and calcium pyrophosphate (CPP) into the chitosan matrices was associated with an increase in pore size, density and compressive strength and modulus, and a decrease in porosity and swelling ratio of the scaffolds. The strongest composite scaffolds in this study with a chitosan: HW fibers weight ratio of 1:1 showed a mean porosity of 69% and a mean strength and modulus of 420kPa and 3.87MPa, respectively. The in vitro bioactivity of the composites was confirmed by the formation of a calcium phosphate rich layer on the surface of soaked scaffolds in simulated body fluid. The findings of this initial work indicate that the chitosan-multiphasic calcium phosphate short fibers may be a suitable material for bone scaffolding. PMID:27179144

  6. Effect of heat treatment on pulsed laser deposited amorphous calcium phosphate coatings.

    PubMed

    García, F; Arias, J L; Mayor, B; Pou, J; Rehman, I; Knowles, J; Best, S; León, B; Pérez-Amor, M; Bonfield, W

    1998-01-01

    Amorphous calcium phosphate coatings were produced by pulsed laser deposition from targets of nonstoichiometric hydroxyapatite (Ca/P = 1.70) at a low substrate temperature of 300 degrees C. They were heated in air at different temperatures: 300, 450, 525 and 650 degrees C. Chemical and structural analyses of these coatings were performed using X-ray diffraction (XRD), FTIR, and SEM, XRD analysis of the as-deposited and heated coatings revealed that their crystallinity improved as heat treatment temperature increased. The main phase was apatitic, with some beta-tricalcium phosphate in the coatings heated at 525 and 600 degrees C. In the apatitic phase there was some carbonate substitution for phosphate and hydroxyl ions at 450 degrees C and almost solely for phosphate at 525 and 600 degrees C as identified by FTIR. This was accompanied by a higher hydroxyl content at 525 and 600 degrees C. At 450 degrees C a texture on the coating surface was observable by SEM that was attributable to a calcium hydroxide and calcite formation by XRD. These phases almost disappeared at 600 degrees C, probably due to a transformation into calcium oxide.

  7. Effect of different calcium phosphate scaffold ratios on odontogenic differentiation of human dental pulp cells.

    PubMed

    AbdulQader, Sarah Talib; Kannan, Thirumulu Ponnuraj; Rahman, Ismail Ab; Ismail, Hanafi; Mahmood, Zuliani

    2015-04-01

    Calcium phosphate (CaP) scaffolds have been widely and successfully used with osteoblast cells for bone tissue regeneration. However, it is necessary to investigate the effects of these scaffolds on odontoblast cells' proliferation and differentiation for dentin tissue regeneration. In this study, three different hydroxyapatite (HA) to beta tricalcium phosphate (β-TCP) ratios of biphasic calcium phosphate (BCP) scaffolds, BCP20, BCP50, and BCP80, with a mean pore size of 300μm and 65% porosity were prepared from phosphoric acid (H2PO4) and calcium carbonate (CaCO3) sintered at 1000°C for 2h. The extracts of these scaffolds were assessed with regard to cell viability and differentiation of odontoblasts. The high alkalinity, more calcium, and phosphate ions released that were exhibited by BCP20 decreased the viability of human dental pulp cells (HDPCs) as compared to BCP50 and BCP80. However, the cells cultured with BCP20 extract expressed high alkaline phosphatase activity and high expression level of bone sialoprotein (BSP), dental matrix protein-1 (DMP-1), and dentin sialophosphoprotein (DSPP) genes as compared to that cultured with BCP50 and BCP80 extracts. The results highlighted the effect of different scaffold ratios on the cell microenvironment and demonstrated that BCP20 scaffold can support HDPC differentiation for dentin tissue regeneration.

  8. Effects of calcium phosphate bioceramics on skeletal muscle cells.

    PubMed

    Sun, J S; Tsuang, Y H; Yao, C H; Liu, H C; Lin, F H; Hang, Y S

    1997-02-01

    With advances in ceramics technology, calcium phosphate bioceramics have been applied as bone substitutes. The effects of implants on bony tissue have been investigated. The effects upon adjacent skeletal muscles have not been determined. The focus of this work is to elucidate the biological effects of various calcium phosphate bioceramics on skeletal muscles. Four different kinds of powder of calcium phosphate biomaterials including beta-tricalcium phosphate (beta-TCP), hydroxyapatite (HA), beta-dicalcium pyrophosphate (beta-DCP) and sintered beta-dicalcium pyrophosphate (SDCP), were tested by myoblast cell cultures. The results were analyzed by cell count, cell morphology and concentration of transforming growth factor beta 1 (TGF-beta 1) in culture medium. The cell population and TGF-beta 1 concentration of the control sample increased persistently as the time of culture increased. The changes in cell population and TGF-beta 1 concentration in culture medium of the beta-TCP and HA were quite low in the first 3 days of culture, then increased gradually toward the seventh day. The changes in cell population and TGF-beta 1 concentration in culture medium of the silica, beta-DCP, and SDCP were quite similar. They were lower during the first day of culture but increased and reached that of the control medium after 7 days' culture. Most cells on B-TCP and HA diminished in size with radially spread, long pseudopods. We conclude that HA and beta-TCP are thought to have an inhibitory effect on growth of the myoblasts. The HA and beta-TCP may interfere with the repair and regeneration of injured skeletal muscle after orthopedic surgery.

  9. In vitro elution of vancomycin from biodegradable osteoconductive calcium phosphate-polycaprolactone composite beads for treatment of osteomyelitis.

    PubMed

    Makarov, C; Cohen, V; Raz-Pasteur, A; Gotman, I

    2014-10-01

    In this work, osteoconductive composite materials comprising a large volume fraction of a bioresorbable calcium phosphate ceramic (CaP) and a smaller amount of a polycaprolactone polymer (PCL) were studied as a degradable antibiotic carrier material for treatment of osteomyelitis. Beads loaded with 1 and 4wt.% vancomycin were prepared by admixing dissolved drug to an in situ synthesized dicalcium phosphate (DCP)-PCL or solution-mixed beta-tricalcium phosphate (βTCP)-PCL composite powder followed by high pressure consolidation of the blend at room temperature. Vancomycin release was measured in phosphate-buffered saline (PBS) at 37°C. All the beads gradually released the drug over the period of 4-11weeks, depending on the composite matrix homogeneity and porosity. Mathematical modeling using the Peppas equation showed that vancomycin elution was diffusion controlled. The stability of the antibiotic after high pressure application at room temperature was demonstrated by high-performance liquid chromatography-mass spectrometry (HPLC-MS) studies and MIC testing. The preservation of the structure and activity of vancomycin during the processing of composite beads and its sustained in vitro release profile suggest that high pressure consolidated CaP-PCL beads may be useful in the treatment of chronic bone infections as resorbable delivery vehicles of vancomycin and even of thermally unstable drug substances.

  10. A novel squid pen chitosan/hydroxyapatite/β-tricalcium phosphate composite for bone tissue engineering.

    PubMed

    Shavandi, Amin; Bekhit, Alaa El-Din A; Sun, Zhifa; Ali, Azam; Gould, Maree

    2015-10-01

    Squid pen chitosan was used in the fabrication of biocomposite scaffolds for bone tissue engineering. Hydroxyapatite (HA) and beta-tricalcium phosphate (β-TCP) obtained from waste mussel shells were used as the calcium phosphate source. The composite was prepared using 2.5% tripolyphosphate (TPP) and 1% glycerol as a cross-linker and plasticizer, respectively. The weight percent (wt.%) ratios of the ceramic components in the composite were 20/10/70, 30/20/50 and 40/30/30 (HA/β-TCP/Chi). The biodegradation rate and structural properties of the scaffolds were investigated. Scanning electron microscopy (SEM) and microCT(μCT) results indicated that the composites have a well defined lamellar structure with an average pore size of 200 μm. The porosity of the composites decreased from 88 to 56% by increasing the ratio of HA/β-TCP from 30 to 70%. After 28 days of incubation in a physiological solution, the scaffolds were degraded by approximately 30%. In vitro investigations showed that the composites were cytocompatible and supported the growth of L929 and Saos-2 cells. The obtained data suggests that the squid pen chitosan composites are potential candidates for bone regeneration.

  11. Polylactic acid-phosphate glass composite foams as scaffolds for bone tissue engineering.

    PubMed

    Georgiou, G; Mathieu, L; Pioletti, D P; Bourban, P-E; Månson, J-A E; Knowles, J C; Nazhat, S N

    2007-02-01

    Phosphate glass (PG) of the composition 0.46(CaO)-0.04(Na(2)O)-0.5(P(2)O(5)) was used as filler in poly-L-lactic acid (PLA) foams developed as degradable scaffolds for bone tissue engineering. The effect of PG on PLA was assessed both in bulk and porous composite foams. Composites with various PG content (0, 5, 10, and 20 wt %) were melt-extruded, and either compression-molded or foamed through supercritical CO(2). Dynamic mechanical analysis on the bulk composites showed that incorporating 20 wt % PG resulted in a significant increase in storage modulus. Aging studies in deionized water in terms of weight loss, pH change, and ion release inferred that the degradation was due to PG dissolution, and dependent on the amount of glass in the composites. Foaming was only possible for composites containing 5 and 10 wt % PG, as an increase in PG increased the foam densities; however, the level of porosity was maintained above 75%. PLA-T(g) in the foams was higher than those obtained for the bulk. Compressive moduli showed no significant reinforcement with glass incorporation in either expansion direction, indicating no anisotropy. Biocompatibility showed that proliferation of human fetal bone cells was more rapid for PLA compared to PLA-PG foams. However, the proliferation rate of PLA-PG foams were similar to those obtained for foams of PLA with either hydroxyapatite or beta-tricalcium phosphate.

  12. Surface potential and osteoblast attraction to calcium phosphate compounds is affected by selected alkaline hydrolysis processing.

    PubMed

    Smith, I O; Baumann, M J; Obadia, L; Bouler, J-M

    2004-08-01

    This study examines the link(s) between the suspension behavior of calcium deficient apatites (CDAs) and biphasic calcium phosphate (BCP), as measured by the zeta-potential, with respect to both whole bone and osteoblasts. CDA is fabricated by hydrolyzing an acidic CaP such as dicalcium diphosphate dihydrate (DCPD; CaHPO4.2H2O) and has a structure and composition close to bone apatite. Sintering CDA results in the formation of BCP ceramics consisting of mixtures of hydroxyapatite (HA) and beta-tricalcium phosphate (beta-TCP), with the HA/beta-TCP weight ratio proportional to the Ca/P ratio of CDA. The choice of the base for the DCPD hydrolysis allows various ionic partial substitution of the formed CDA. Na for Ca partial substitution is of interest because of the resulting improvement in mechanical properties of the resulting BCP ceramics and NH4OH was used as a negative control. The zeta-potential was measured for these materials and the stability of the ceramic to bone interaction calculated. zeta-potential values decrease for CDA(NH4OH) versus CDA(NaOH) and increase for BCP(NH4OH) versus BCP(NaOH). While results of these analyses indicate that NH4OH and NaOH processed CDA and BCP will likely yield osteoblast attachment in vivo, differences in the zeta-potentials may explain varying degrees of cell attachment.

  13. Hybrid composites of calcium phosphate granules, fibrin glue, and bone marrow for skeletal repair.

    PubMed

    Le Nihouannen, Damien; Goyenvalle, Eric; Aguado, Eric; Pilet, Paul; Bilban, Melitta; Daculsi, Guy; Layrolle, Pierre

    2007-05-01

    Synthetic bone substitutes, such as calcium phosphate ceramics, give good results in clinical applications. In order to adapt to surgical sites, bioceramics come in the form of blocks or granules, and are either dense or porous. Combining these bioceramics with fibrin glue provides a mouldable and self-hardening composite biomaterial with the biochemical properties of each component. Critical-sized defects in the femoral condyle of rabbits were filled with TricOs/fibrin glue/bone marrow hybrid/composite material. The TricOs granules (1-2 mm) were composed of hydroxyapatite and beta tricalcium phosphate (60/40 in weight). The fibrin glue was composed of fibrinogen, thrombin and other biological factors and mixed with MBCP granules either simultaneously or sequentially. Bone marrow was also added to the MBCP/fibrin composite prior to filling the defects. After 3, 6, 12, and 24 weeks of implantation, the newly-formed bone was analysed with histology, histomorphometry and mechanical tests. The newly-formed bone had grown centripetally. Simultaneous application of fibrin glue showed better results for mechanical properties than sequential application after 6 weeks. Around 40% of bone had formed after 24 weeks in the three groups. Although the addition of bone marrow did not improve bone formation, the MBCP/fibrin material could be used in clinical bone filling applications. PMID:17117470

  14. Biogenic Calcium Phosphate Transformation in Soils over Millennium Time Scales

    SciTech Connect

    Sato, S.; Neves, E; Solomon, D; Liang, B; Lehmann, J

    2009-01-01

    Changes in bioavailability of phosphorus (P) during pedogenesis and ecosystem development have been shown for geogenic calcium phosphate (Ca-P). However, very little is known about long-term changes of biogenic Ca-P in soil. Long-term transformation characteristics of biogenic Ca-P were examined using anthropogenic soils along a chronosequence from centennial to millennial time scales. Phosphorus fractionation of Anthrosols resulted in overall consistency with the Walker and Syers model of geogenic Ca-P transformation during pedogenesis. The biogenic Ca-P (e.g., animal and fish bones) disappeared to 3% of total P within the first ca. 2,000 years of soil development. This change concurred with increases in P adsorbed on metal-oxides surfaces, organic P, and occluded P at different pedogenic time. Phosphorus K-edge X-ray absorption near-edge structure (XANES) spectroscopy revealed that the crystalline and therefore thermodynamically most stable biogenic Ca-P was transformed into more soluble forms of Ca-P over time. While crystalline hydroxyapatite (34% of total P) dominated Ca-P species after about 600-1,000 years, {Beta}-tricalcium phosphate increased to 16% of total P after 900-1,100 years, after which both Ca-P species disappeared. Iron-associated P was observable concurrently with Ca-P disappearance. Soluble P and organic P determined by XANES maintained relatively constant (58-65%) across the time scale studied. Conclusions - Disappearance of crystalline biogenic Ca-P on a time scale of a few thousand years appears to be ten times faster than that of geogenic Ca-P.

  15. Hierarchical pore structure of calcium phosphate scaffolds by a combination of gel-casting and multiple tape-casting methods.

    PubMed

    Sánchez-Salcedo, S; Werner, J; Vallet-Regí, M

    2008-07-01

    The objective of this work was to design hierarchical pore structure scaffolds with potential applications in bone tissue regeneration. For that purpose, a bioceramic material such as biphasic calcium phosphate, which consists of a mixture of hydroxyapatite and beta-tricalcium phosphate, was selected. Multilayer pieces (MLP) with hierarchical pore structure were developed employing a new technique that combines gel casting and adding porogens, using multiple tape-casting methods. Pieces with functionally graded porosity were fabricated using porogens with different sizes. The porogens used were Porlat K85 and Porlat K86 with diameters <150 microm and 150-300 microm, respectively. Two types of sintered tapes, with different porosity, no cracking and enough interconnection size were selected. MLP with hierarchical pore structure were designed by the multiple tape-casting method. Interconnected pores whose sizes increase from interior tapes (1.6-3.6 microm) towards exterior tapes (20-51.5 microm) and interpenetration between tapes were achieved. Delamination or cracking were not observed after heat treatment. The flexural strength of pieces was investigated by the three-point bending test. This new combination of methods offers the possibility of manufacturing scaffolds with interconnected pore sizes ranging from 1.6 to 51.5 microm.

  16. Osteoclastogenesis and Osteoclastic Resorption of Tricalcium Phosphate: Effect of Strontium and Magnesium Doping

    PubMed Central

    Roy, Mangal; Bose, Susmita

    2012-01-01

    Bone substitute materials are required to support the remodeling process, which consists of osteoclastic resorption and osteoblastic synthesis. Osteoclasts, the bone resorbing cells, generate from differentiation of hemopoietic mononuclear cells. In the present study we have evaluated the effects of 1.0 wt% strontium (Sr) and 1.0 wt% magnesium (Mg) doping in beta-tricalcium phosphate (β-TCP) on the differentiation of mononuclear cells into osteoclast-like cells and its resorptive activity. In vitro osteoclast-like cell formation, adhesion, and resorption were studied using osteoclast precursor RAW 264.7 cell, supplemented with receptor activator of nuclear factor κβ ligand (RANKL). Osteoclast-like cell formation was noticed on pure and Sr doped β-TCP samples at day 8 which was absent on Mg doped β-TCP samples indicating decrease in initial osteoclast differentiation due to Mg doping. After 21 days of culture, osteoclast-like cell formation was evident on all samples with osteoclastic markers such as actin ring, multiple nuclei, and presence of vitronectin receptor αvβ3 integrin. After osteoclast differentiation, all substrates showed osteoclast-like cell mediated degradation, however; significantly restricted for Mg doped β-TCP samples. Our present results indicated substrate chemistry controlled osteoclast differentiation and resorptive activity which can be used in designing TCP based resorbable bone substitutes with controlled degradation properties. PMID:22566212

  17. The effects of calcium phosphate particles on the growth of osteoblasts.

    PubMed

    Sun, J S; Tsuang, Y H; Liao, C J; Liu, H C; Hang, Y S; Lin, F H

    1997-12-01

    With advances in ceramics technology, calcium phosphate bioceramics have been applied as bone substitutes for several decades. The focus of this work is to elucidate the biocompatibility of the particulates of various calcium phosphate cytotoxicities. Four different kinds of calcium phosphate powders, including beta-tricalcium phosphate (beta-TCP), hydroxyapatite (HA), beta-dicalcium pyrophosphate (beta-DCP), and sintered beta-dicalcium pyrophosphate (SDCP), were tested by osteoblast cell culture. The results were analyzed by cell count, concentration of transforming growth factor-beta 1 (TGF-beta 1), alkaline phosphatase (ALP), and prostaglandin E2 (PGE2) in culture media. The changes were most significant when osteoblasts were cultured with beta-TCP and HA bioceramics. The changes in cell population of the beta-TCP and HA were quite low in the first 3 days, then increased gradually toward the seventh day. The changes in TGF-beta 1 concentration in culture medium inversely related to the changes in cell population. The ALP titer in the culture media of the beta-TCP and HA were quite high in the first 3 days, then decreased rapidly between the third and seventh days. The concentrations of PGE2 in the culture media tested were quite high on the first day, decreased rapidly to the third day, and then gradually until the seventh day. The changes in the beta-DCP and SDCP were quite similar to those of HA and beta-TCP but much less significant. We conclude that HA and beta-TCP have an inhibitory effect on the growth of osteoblasts. The inhibitins effects of the HA and beta-TCP powders on the osteoblast cell cultures possibly are mediated by the increased synthesis of PGE2.

  18. Porous hydroxyapatite and biphasic calcium phosphate ceramics promote ectopic osteoblast differentiation from mesenchymal stem cells

    NASA Astrophysics Data System (ADS)

    Zhang, Lingli; Hanagata, Nobutaka; Maeda, Megumi; Minowa, Takashi; Ikoma, Toshiyuki; Fan, Hongsong; Zhang, Xingdong

    2009-04-01

    Because calcium phosphate (Ca-P) ceramics have been used as bone substitutes, it is necessary to investigate what effects the ceramics have on osteoblast maturation. We prepared three types of Ca-P ceramics with different Ca-P ratios, i.e. hydroxyapatite (HA), beta-tricalcium phosphate (β-TCP), and biphasic calcium phosphate (BCP) ceramics with dense-smooth and porous structures. Comprehensive gene expression microarray analysis of mouse osteoblast-like cells cultured on these ceramics revealed that porous Ca-P ceramics considerably affected the gene expression profiles, having a higher potential for osteoblast maturation. In the in vivo study that followed, porous Ca-P ceramics were implanted into rat skeletal muscle. Sixteen weeks after the implantation, more alkaline-phosphatase-positive cells were observed in the pores of hydroxyapatite and BCP, and the expression of the osteocalcin gene (an osteoblast-specific marker) in tissue grown in pores was also higher in hydroxyapatite and BCP than in β-TCP. In the pores of any Ca-P ceramics, 16 weeks after the implantation, we detected the expressions of marker genes of the early differentiation stage of chondrocytes and the complete differentiation stage of adipocytes, which originate from mesenchymal stem cells, as well as osteoblasts. These marker gene expressions were not observed in the muscle tissue surrounding the implanted Ca-P ceramics. These observations indicate that porous hydroxyapatite and BCP had a greater potential for promoting the differentiation of mesenchymal stem cells into osteoblasts than β-TCP.

  19. Osteogenic effect of tricalcium phosphate substituted by magnesium associated with Genderm® membrane in rat calvarial defect model.

    PubMed

    Costa, Neusa M F; Yassuda, Debora H; Sader, Marcia S; Fernandes, Gustavo V O; Soares, Glória D A; Granjeiro, José M

    2016-04-01

    Beta-tricalcium phosphate (β-TCP) is one of the most widely employed bioresorbable materials for bone repair since it shows excellent biological compatibility, osteoconductivity and resorbability. The incorporation of divalent cations such as magnesium onto the β-TCP structure (β-TCMP) may improve the biological response to the material through the release of bioactive ions. The objective of this study was to evaluate, on a rat calvarial critical size grafting model, the bone regeneration process using β-TCP and β-TMCP granules by histomorphometric analysis. Results demonstrated that six months after bone grafting, the association of GBR (guided bone regeneration) using a membrane (GenDerm®) and granules of β-TCP and β-TCMP significantly improves bone repair in the treatment of critical-size defect in rat skulls, in comparison to untreated defects or GBR alone, leading to a bone level approximately four to five-fold greater than in the blood clot group. The β-TCMP+GenDerm® membrane group presented 40.5% of the defect area filled by newly-formed bone, even at the central part of the defect, rather than only at the border, as seen in the other experimental groups. PMID:26838825

  20. Microstructure, mechanical characteristics and cell compatibility of β-tricalcium phosphate reinforced with biodegradable Fe-Mg metal phase.

    PubMed

    Swain, Sanjaya K; Gotman, Irena; Unger, Ronald; Kirkpatrick, C James; Gutmanas, Elazar Y

    2016-01-01

    The use of beta-tricalcium phosphate (β-TCP) ceramic as a bioresorbable bone substitute is limited to non-load-bearing sites by the material׳s brittleness and low bending strength. In the present work, new biocompatible β-TCP-based composites with improved mechanical properties were developed via reinforcing the ceramic matrix with 30 vol% of a biodegradable iron-magnesium metallic phase. β-TCP-15Fe15Mg and β-TCP-24Fe6Mg (vol%) composites were fabricated using a combination of high energy attrition milling, cold sintering/high pressure consolidation of powders at room temperature and annealing at 400 °C. The materials synthesized had a hierarchical nanocomposite structure with a nanocrystalline β-TCP matrix toughened by a finely dispersed nanoscale metallic phase (largely Mg) alongside micron-scale metallic reinforcements (largely Fe). Both compositions exhibited high strength characteristics; in bending, they were about 3-fold stronger than β-TCP reinforced with 30 vol% PLA polymer. Immersion in Ringer׳s solution for 4 weeks resulted in formation of corrosion products on the specimens׳ surface, a few percent weight loss and about 50% decrease in bending strength. In vitro studies of β-TCP-15Fe15Mg composite with human osteoblast monocultures and human osteoblast-endothelial cell co-cultures indicated that the composition was biocompatible for the growth and survival of both cell types and cells exhibited tissue-specific markers for bone formation and angiogenesis, respectively. PMID:26409234

  1. Minimally Invasive Alveolar Ridge Preservation Utilizing an In Situ Hardening β-Tricalcium Phosphate Bone Substitute: A Multicenter Case Series

    PubMed Central

    Leventis, Minas D.; Fairbairn, Peter; Kakar, Ashish; Leventis, Angelos D.; Margaritis, Vasileios; Lückerath, Walter; Horowitz, Robert A.; Rao, Bappanadu H.; Lindner, Annette; Nagursky, Heiner

    2016-01-01

    Ridge preservation measures, which include the filling of extraction sockets with bone substitutes, have been shown to reduce ridge resorption, while methods that do not require primary soft tissue closure minimize patient morbidity and decrease surgical time and cost. In a case series of 10 patients requiring single extraction, in situ hardening beta-tricalcium phosphate (β-TCP) granules coated with poly(lactic-co-glycolic acid) (PLGA) were utilized as a grafting material that does not necessitate primary wound closure. After 4 months, clinical observations revealed excellent soft tissue healing without loss of attached gingiva in all cases. At reentry for implant placement, bone core biopsies were obtained and primary implant stability was measured by final seating torque and resonance frequency analysis. Histological and histomorphometrical analysis revealed pronounced bone regeneration (24.4 ± 7.9% new bone) in parallel to the resorption of the grafting material (12.9 ± 7.7% graft material) while high levels of primary implant stability were recorded. Within the limits of this case series, the results suggest that β-TCP coated with polylactide can support new bone formation at postextraction sockets, while the properties of the material improve the handling and produce a stable and porous bone substitute scaffold in situ, facilitating the application of noninvasive surgical techniques. PMID:27190516

  2. Minimally Invasive Alveolar Ridge Preservation Utilizing an In Situ Hardening β-Tricalcium Phosphate Bone Substitute: A Multicenter Case Series.

    PubMed

    Leventis, Minas D; Fairbairn, Peter; Kakar, Ashish; Leventis, Angelos D; Margaritis, Vasileios; Lückerath, Walter; Horowitz, Robert A; Rao, Bappanadu H; Lindner, Annette; Nagursky, Heiner

    2016-01-01

    Ridge preservation measures, which include the filling of extraction sockets with bone substitutes, have been shown to reduce ridge resorption, while methods that do not require primary soft tissue closure minimize patient morbidity and decrease surgical time and cost. In a case series of 10 patients requiring single extraction, in situ hardening beta-tricalcium phosphate (β-TCP) granules coated with poly(lactic-co-glycolic acid) (PLGA) were utilized as a grafting material that does not necessitate primary wound closure. After 4 months, clinical observations revealed excellent soft tissue healing without loss of attached gingiva in all cases. At reentry for implant placement, bone core biopsies were obtained and primary implant stability was measured by final seating torque and resonance frequency analysis. Histological and histomorphometrical analysis revealed pronounced bone regeneration (24.4 ± 7.9% new bone) in parallel to the resorption of the grafting material (12.9 ± 7.7% graft material) while high levels of primary implant stability were recorded. Within the limits of this case series, the results suggest that β-TCP coated with polylactide can support new bone formation at postextraction sockets, while the properties of the material improve the handling and produce a stable and porous bone substitute scaffold in situ, facilitating the application of noninvasive surgical techniques.

  3. Minimally Invasive Alveolar Ridge Preservation Utilizing an In Situ Hardening β-Tricalcium Phosphate Bone Substitute: A Multicenter Case Series.

    PubMed

    Leventis, Minas D; Fairbairn, Peter; Kakar, Ashish; Leventis, Angelos D; Margaritis, Vasileios; Lückerath, Walter; Horowitz, Robert A; Rao, Bappanadu H; Lindner, Annette; Nagursky, Heiner

    2016-01-01

    Ridge preservation measures, which include the filling of extraction sockets with bone substitutes, have been shown to reduce ridge resorption, while methods that do not require primary soft tissue closure minimize patient morbidity and decrease surgical time and cost. In a case series of 10 patients requiring single extraction, in situ hardening beta-tricalcium phosphate (β-TCP) granules coated with poly(lactic-co-glycolic acid) (PLGA) were utilized as a grafting material that does not necessitate primary wound closure. After 4 months, clinical observations revealed excellent soft tissue healing without loss of attached gingiva in all cases. At reentry for implant placement, bone core biopsies were obtained and primary implant stability was measured by final seating torque and resonance frequency analysis. Histological and histomorphometrical analysis revealed pronounced bone regeneration (24.4 ± 7.9% new bone) in parallel to the resorption of the grafting material (12.9 ± 7.7% graft material) while high levels of primary implant stability were recorded. Within the limits of this case series, the results suggest that β-TCP coated with polylactide can support new bone formation at postextraction sockets, while the properties of the material improve the handling and produce a stable and porous bone substitute scaffold in situ, facilitating the application of noninvasive surgical techniques. PMID:27190516

  4. Effect of several additives and their admixtures on the physico-chemical properties of a calcium phosphate cement.

    PubMed

    Bohner, M; Merkle, H P; Landuyt, P V; Trophardy, G; Lemaitre, J

    2000-02-01

    Combinations of citrate (C6H5O(7)3-), pyrophosphate (P2O(7)4-) and sulfate (SO(4)2-) ions were used to modify the physico-chemical properties of a calcium phosphate cement (CPC) composed of beta-tricalcium phosphate (beta-TCP) and phosphoric acid (PA) solution. The results obtained with only one additive at a time are similar to those previously published. New facts are: the positive effect of C6H5O(7)3- ions on cement failure strain and their negative effect on cement pH. The position of the setting time maximum measured at an SO(4)2- concentration of 0.09 M was not displaced by the addition of C6H5O(7)3- and P2O(7)4- ions. However, the effect of SO(4)2- ions on the setting time was depressed by C6H5O(7)3- ions. Moreover, no increase in tensile strength was observed when increasing amounts of SO(4)2- were added into a C6H5O(7)3--containing cement. The latter results suggest a competitive effect of C6H5O(7)3- and SO(4)2- on setting time and tensile strength. Anhydrous dicalcium phosphate (DCP; CaHPO4) appeared in cement samples dried just after setting, but not in cement samples incubated for 24 h in deionized water before the drying step. It is believed that the setting reaction is stopped by the drying step, leaving a low internal pH in the sample, hence providing favorable conditions for the transformation of dicalcium phosphate dihydrate (DCPD) into DCP. Interestingly, even though C6H5O(7)3- ions dramatically lowered the equilibrium pH of the cement with 5 ml of deionized water, they still prevented the occurrence of the transformation of DCPD into DCP.

  5. Resolution-enhanced Fourier transform infrared spectroscopy study of the environment of phosphate ions in the early deposits of a solid phase of calcium-phosphate in bone and enamel, and their evolution with age. I: Investigations in the upsilon 4 PO4 domain.

    PubMed

    Rey, C; Shimizu, M; Collins, B; Glimcher, M J

    1990-06-01

    In order to investigate the possible existence in biological and poorly crystalline synthetic apatites of local atomic organizations different from that of apatite, resolution-enhanced, Fourier transform infrared spectroscopy studies were carried out on chicken bone, pig enamel, and poorly crystalline synthetic apatites containing carbonate and HPO4(2-) groups. The spectra obtained were compared to those of synthetic well crystallized apatites (stoichiometric hydroxyapatite, HPO4(2-)-containing apatite, type B carbonate apatite) and nonapatitic calcium phosphates which have been suggested as precursors of the apatitic phase [octacalcium phosphate (OCP), brushite, and beta tricalcium phosphate and whitlockite]. The spectra of bone and enamel, as well as poorly crystalline, synthetic apatite in the upsilon 4 PO4 domain, exhibit, in addition to the three apatitic bands, three absorption bands that were shown to be independent of the organic matrix. Two low-wave number bands at 520-530 and 540-550 cm-1 are assigned to HPO4(2-). Reference to known calcium phosphates shows that bands in this domain also exist in HPO4(2-)-containing apatite, brushite, and OCP. However, the lack of specific absorption bands prevents a clear identification of these HPO4(2-) environments. The third absorption band (610-615 cm-1) is not related to HPO4(2-) or OH- ions. It appears to be due to a labile PO4(3-) environment which could not be identified with any phosphate environment existing in our reference samples, and thus seems specific of poorly crystalline apatites. Correlation of the variations in band intensities show that 610-615 cm-1 band is related to an absorption band at 560 cm-1 superimposed on an apatite band. All the nonapatitic phosphate environments were shown to decrease during aging of enamel, bone, and synthetic apatites. Moreover, EDTA etching show that the labile PO4(3-) environment exhibited a heterogeneous distribution in the insoluble precipitate.

  6. Chemical, modulus and cell attachment studies of reactive calcium phosphate filler-containing fast photo-curing, surface-degrading, polymeric bone adhesives.

    PubMed

    Abou Neel, E A; Palmer, G; Knowles, J C; Salih, V; Young, A M

    2010-07-01

    The initial structure, setting and degradation processes of a poly(lactide-co-propylene glycol-co-lactide) dimethacrylate adhesive filled with 50, 60 or 70 wt.% reactive calcium phosphates (monocalcium phosphate monohydrate (MCPM)/beta-tricalcium phosphate (beta-TCP)) have been assessed using nuclear magnetic resonance, Fourier transform infrared spectroscopy, Raman, X-ray powder diffraction and gravimetric studies. Filler incorporation reduced the rapid light-activated monomer polymerization rates slightly, but not the final levels. Upon immersion in water for 24h, the set composite mass and volume increased due to water sorption. This promoted initial soluble MCPM loss from the composite surfaces, but also its reaction and monetite precipitation within the specimen bulk. After 48 h, composite gravimetric and chemical studies were consistent with surface erosion of polymer with reacted/remaining filler. The filled formulations exhibited more rapid early water sorption and subsequent surface erosion than the unfilled polymer. Calcium and phosphate release profiles and solution pH measurements confirmed early loss of surface MCPM with protons from polymer degradation products. At later times, the slower release of monetite/beta-TCP buffered composite storage solutions at approximately 5 instead of 3.2 for the unfilled polymer. Incorporation of filler increased both the early and later time material modulus. At intermediate times this effect was lost, presumably as a result of enhanced water sorption. The early modulus values obtained fell within the range reported for cancellous bone. Despite surface degradation, initial human mesenchymal cell attachment to both composites and polymer could be comparable with a non-degrading positive Thermanox control. These studies indicate that the filled formulations may be good candidates for bone repair. Release of calcium and phosphate ions provides components essential for such repair.

  7. Phosphate salts

    MedlinePlus

    ... taken by mouth or used as enemas. Indigestion. Aluminum phosphate and calcium phosphate are FDA-permitted ingredients ... Phosphate salts containing sodium, potassium, aluminum, or calcium are LIKELY SAFE for most people when taken by mouth short-term, when sodium phosphate is inserted into the ...

  8. Utility of tricalcium phosphate and osteogenic matrix cell sheet constructs for bone defect reconstruction

    PubMed Central

    Ueha, Tomoyuki; Akahane, Manabu; Shimizu, Takamasa; Uchihara, Yoshinobu; Morita, Yusuke; Nitta, Naoya; Kido, Akira; Inagaki, Yusuke; Kawate, Kenji; Tanaka, Yasuhito

    2015-01-01

    AIM: To determine the effects of transplanting osteogenic matrix cell sheets and beta-tricalcium phosphate (TCP) constructs on bone formation in bone defects. METHODS: Osteogenic matrix cell sheets were prepared from bone marrow stromal cells (BMSCs), and a porous TCP ceramic was used as a scaffold. Three experimental groups were prepared, comprised of TCP scaffolds (1) seeded with BMSCs; (2) wrapped with osteogenic matrix cell sheets; or (3) both. Constructs were implanted into a femoral defect model in rats and bone growth was evaluated by radiography, histology, biochemistry, and mechanical testing after 8 wk. RESULTS: In bone defects, constructs implanted with cell sheets showed callus formation with segmental or continuous bone formation at 8 wk, in contrast to TCP seeded with BMSCs, which resulted in bone non-union. Wrapping TCP constructs with osteogenic matrix cell sheets increased their osteogenic potential and resulting bone formation, compared with conventional bone tissue engineering TCP scaffolds seeded with BMSCs. The compressive stiffness (mean ± SD) values were 225.0 ± 95.7, 30.0 ± 11.5, and 26.3 ± 10.6 MPa for BMSC/TCP/Sheet constructs with continuous bone formation, BMSC/TCP/Sheet constructs with segmental bone formation, and BMSC/TCP constructs, respectively. The compressive stiffness of BMSC/TCP/Sheet constructs with continuous bone formation was significantly higher than those with segmental bone formation and BMSC/TCP constructs. CONCLUSION: This technique is an improvement over current methods, such as TCP substitution, and is useful for hard tissue reconstruction and inducing earlier bone union in defects. PMID:26131318

  9. Calcium phosphate scaffolds mimicking the gradient architecture of native long bones.

    PubMed

    Lindner, Markus; Bergmann, Christian; Telle, Rainer; Fischer, Horst

    2014-10-01

    The synthesis of beta-tricalcium phosphate (β-TCP) scaffolds offering both the macroporous inner structure required for proper in vivo degradation and a non-macroporous outer structure for the enhancement of mechanical properties continues to be a challenge. The hypothesis of this study was to realize biomimetic β-TCP scaffolds with a macroporous inner structure and a compact outer structure using a lost wax casting technique. The porosity, macropore size, interconnectivity of the inner porous structure, and diameter of the outer compact structure were adjusted to specific values using a three-dimensional wax printer to manufacture the wax molds for the casting process. After the slip casting, the wax was pyrolyzed and the specimens were sintered. The resulting graded β-TCP scaffolds (porous + compact) were characterized and compared with β-TCP scaffolds with overall apparent macropores (only porous) and samples without macropores (only compact). The porosity and the compressive strength of the only compact, porous + compact, and only porous β-TCP samples were 31.4 ± 0.4 vol %, 55.6 ± 0.9 vol %, and 66.9 ± 0.4 vol % and 192 ± 7 MPa, 36 ± 2 MPa, and 9 ± 1 MPa, respectively. The macropore size was 500 µm and the micropore size was up to 10 µm, both featuring a completely open porous structure. From these results, we conclude that the lost wax casting technique offers an excellent method for the fabrication of β-TCP scaffolds with an inner macroporous structure and compact outer structure which mimics the cancellous and cortical structure of natural bone.

  10. Effects of Zinc and Strontium Substitution in Tricalcium Phosphate on Osteoclast Differentiation and Resorption

    PubMed Central

    Roy, Mangal; Fielding, Gary; Bandyopadhyay, Amit; Bose, Susmita

    2013-01-01

    Bone replacement materials must be able to regulate both osteoblastic synthesis of new bone and osteoclastic resorption process in order to maintain the balance of bone remodeling. Osteoclasts generate from differentiation of mononuclear cells. In the present study, we have studied the osteoclast-like-cells responses (differentiation from mononuclear cells and resorption) to beta tricalcium phosphate (β-TCP) doped with zinc (Zn) and strontium (Sr). Osteoclast-like-cells differentiation and resorption was studied in vitro using osteoclast-like-cells precursor RAW 264.7 cell, supplemented with receptor activator of nuclear factor κβ ligand (RANKL). Morphological and immunohistochemical analysis confirmed successful differentiation of osteoclast-like-cells on the doped and undoped β-TCP substrates after 8 days of culture. Cells on the substrate surface expressed specific osteoclast markers such as; actin ring, multiple nucleus, tartrate-resistant acid phosphatase (TRAP) synthesis, and vitronectin receptor. However, quantitative TRAP assay indicated the inhibiting effect of Zn on osteoclast differentiation. Although, Zn doped β-TCP restricted osteoclast-like-cells differentiation, the samples were resorbed much faster. An increased resorption pit volume was noticed on Zn doped β-TCP samples after 28 days of culture compared to pure and Sr doped β-TCP. In this work, we demonstrated that β-TCP bone substitute materials can be successfully resorbed by osteoclast-like-cells, where both osteoclast-like-cells differentiation and resorption were modulated by Zn and/or Sr doping- a much needed property for successful bone remodeling. PMID:24244866

  11. [Phosphate binders].

    PubMed

    Heeb, Rita M

    2016-06-01

    Phosphate binders to treat hyperphosphataemia are part of the medication regime of every dialysis patient. Phosphate binders are taken with every meal (three times a day). Generally, the medication adherence rates of phosphate binders are very low. This is due to inconveniences like their bad taste or their size which makes them hard to swallow. Also nephrologists have differing opinions on phosphate binders as they are aware of the dialysis patients' difficulties to deal with the amount of drugs they are prescribed. Still, phosphate binders are important drugs which have shown potential in reducing mortality by regulating the level of serum phosphate. In order to improve adherence rates, pharmacists have to advise the patients on these drugs' side effects versus the risks associated with omitting their intake. PMID:27439258

  12. Analysis of β-tricalcium phosphate granules prepared with different formulations by nano-computed tomography and scanning electron microscopy.

    PubMed

    Terranova, Lisa; Libouban, Hélène; Mallet, Romain; Chappard, Daniel

    2015-12-01

    Among biomaterials used for filling bone defects, beta-tricalcium phosphate (β-TCP) is suitable in non-bearing bones, particularly in dental implantology, oral and maxillofacial surgery. When β-TCP granules are placed in a bone defect, they occupy the void 3D volume. Little is known about the 3D arrangement of the granules, which depends on the nature and size of the granules. The aim of this study was to examine the 3D architecture of porous β-TCP granules. Granules were prepared with different concentrations of β-TCP powder in slurry (10, 11, 15, 18, 21, and 25 g of β-TCP powder in distilled water). Granules were prepared by the polyurethane foam method. They were analyzed by nano-computed tomography (nanoCT) and compared with scanning electron microscopy (SEM). Commercial granules of hydroxyapatite-β-TCP prepared by the same methodology were also used. The outer and inner architectures of the granules were shown by nanoCT which evidenced macroporosity, internal porosity and microporosity between the sintered grains. Macroporosity was reduced at high concentration and conversely, numerous concave surfaces were observed. Internal porosity, related to the sublimation of the polyurethane foam, was present in all the granules. Microporosity at the grain joints was evidenced by SEM and on 2D nanoCT sections. Granules presented a heterogeneous aspect due to the different mineralization degree of the sintered powder grains in the β-TCP granules; the difference between hydroxyapatite and β-TCP was also evidenced. NanoCT is an interesting method to analyze the fine morphology of biomaterials with a resolution close to synchrotron and better than microcomputed tomography. PMID:25899237

  13. Influence of platelet-rich plasma on osteogenic differentiation of mesenchymal stem cells and ectopic bone formation in calcium phosphate ceramics.

    PubMed

    Kasten, Philip; Vogel, Julia; Luginbühl, Reto; Niemeyer, Philipp; Weiss, Stefan; Schneider, Sven; Kramer, Martin; Leo, Albrecht; Richter, Wiltrud

    2006-01-01

    Platelet-rich plasma (PRP) contains a mixture of growth factors that play an important role in wound and fracture healing. While PRP enhanced bone formation by autogenous cancellous bone grafts, its influence in combination with different bone substitutes remained unknown. This study evaluated the effect of PRP on osteogenic differentiation and ectopic bone formation of human mesenchymal stem cells (MSC) in distinct resorbable calcium phosphate ceramics. Calcium-deficient hydroxyapatite (CDHA) blocks with a large specific surface area (48 m2/g) and beta-tricalcium phosphate (beta-TCP) with a low specific surface area (<0.5 m2/g) were loaded with 2 x 10(5) bone marrow-derived MSC. Half of the specimens were treated with 5-fold concentrated PRP. Biocomposites were implanted subcutaneously into SCID mice or kept under osteogenic culture conditions for 2 weeks before implantation. The addition of PRP increased the specific alkaline phosphatase (ALP) activity (p = 0.012) in undifferentiated MSC/CDHA composites but not in MSC/beta-TCP composites. Osteogenic preinduction was ineffective for CDHA and reduced ALP activity of beta-TCP composites significantly at explantation. Ectopic bone formation was stronger in MSC/CDHA (7/32) compared to MSC/beta-TCP (2/30) composites, but no influence of PRP was evident. In conclusion, the effect of PRP depended on the type of ceramic and the differentiation status of the MSC, and enhanced ALP activity of MSC on the high surface scaffold CDHA only, but PRP did not improve osteogenesis in our setting.

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

    PubMed

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

    2014-05-01

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

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

    PubMed

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

    2014-05-01

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

  16. Mechanical properties and in vitro cellular behavior of zinc-containing nano-bioactive glass doped biphasic calcium phosphate bone substitutes.

    PubMed

    Badr-Mohammadi, Mohammad-Reza; Hesaraki, Saeed; Zamanian, Ali

    2014-01-01

    In the present study, different amounts (0.5-5 wt%) of a sol gel-derived zinc-containing nano-bioactive glass (NBG-Zn) powder were added to biphasic calcium phosphate (BCP). The mixtures were sintered at 1,100-1,300 °C and physical characteristics, mechanical properties, phase composition and morphology of them were studied. The samples were also soaked in human blood plasma for 15 days to evaluate variations in their surface morphologies. Rat calvarium-derived osteoblastic cells were seeded on tops of various samples and cell adhesion, proliferation, and alkaline phosphatase activity were evaluated at different culturing periods. The maximum bending strength (62 MPa) was obtained for BCP containing 0.5 wt% NBG-Zn at temperature 1,200 °C. This value was approximately 80% higher than that of pure BCP. The bending strength failed when both sintering temperature and amount of added NBG-Zn increased. At 1,100 °C, NBG-Zn additive did not change the phase composition of BCP. At temperatures 1,200 and 1,300 °C, both alpha-tricalcium calcium phosphate (α-TCP) and beta-tricalcium phosphate (β-TCP and) phases were detected. However, adding higher amount of NBG-Zn to BCP resulted in elevation of β-TCP at 1,200 °C and progression of α-TCP at 1,300 °C. Based on the microscopic observations, adding 0.5 wt% NBG-Zn to BCP led to disappearance of grain boundaries, reduction of micropores and formation of a monolithic microstructure. No calcium phosphate precipitation was observed on sample surfaces after soaking in blood plasma, but some pores were produced by phase dissolution. The size and volume of these pores were directly proportional to NBG-Zn content. Based on the cell studies, both BCP and NBG-Zn-added BCP samples supported attachment and proliferation of osteoblasts, but higher alkaline phosphatase enzyme was synthesized within the cells cultured on NBG-Zn-added BCP. Overall, biphasic calcium phosphate materials with improved mechanical and biological properties

  17. Electrochemical studies and growth of apatite on molybdenum doped DLC coatings on titanium alloy β-21S

    NASA Astrophysics Data System (ADS)

    Anandan, C.; Mohan, L.; Babu, P. Dilli

    2014-03-01

    Titanium alloy β-21S (Ti-15Mo-3Nb-3Al-0.2Si) was coated with molybdenum doped DLC by Plasma-enhanced chemical vapor deposition and sputtering. XRD, XPS and Raman spectroscopy show that Mo is present in the form of carbide in the coating. XPS of samples immersed in Hanks' solution shows presence of calcium, phosphorous and oxygen in hydroxide/phosphate form on the substrate and Mo-doped DLC. Potentiodynamic polarization studies show that the corrosion resistance and passivation behavior of Mo-doped DLC is better than that of substrate. Electrochemical impedance spectroscopy (EIS) studies show that Mo-doped DLC samples behave like an ideal capacitor in Hanks' solution.

  18. Porous tricalcium phosphate and transforming growth factor used for anterior spine surgery.

    PubMed

    Steffen, T; Stoll, T; Arvinte, T; Schenk, R K

    2001-10-01

    Harvesting autologous bone graft from the iliac crest is associated with considerable secondary morbidity. Bone graft substitutes such as porous ceramics are increasingly used for spinal surgery. This paper presents the results of an animal study in which beta-tricalcium phosphate (beta-TCP) bone substitutes were used for anterior spinal surgery in sheep and baboons. The presented baboon study also investigated the effect of impregnating the ceramic material with transforming growth factor (TGF). In the first study, using the sheep model, a stand-alone instrumented anterior fusion was performed. The animals were randomized into three treatment groups: autologous bone, beta-TCP granules, and sham group. The results were analyzed biomechanically and histologically at three survival intervals: 8, 16 and 32 weeks. An additional animal group was added later, with ceramic pre-filled implants. In the second study, a baboon model was used to assess the osteointegration of a 15-mm-diameter porous beta-TCP block into the vertebral body. The experiment was partially motivated by a new surgical procedure proposed for local bone graft harvest. Three treatment groups were used: beta-TCP plug, beta-TCP plug impregnated with TGF-beta3, and a sham group with empty defect. The evaluation for all animals included computer tomograms at 3 and 6 months, as well as histology at 6 months. In the sheep model, the mechanical evaluation failed to demonstrate differences between treatment groups. This was because massive anterior bone bridges formed in almost all the animals, masking the effects of individual treatments. Histologically, beta-TCP was shown to be a good osteoconductor. While multiple signs of implant micromotion were documented, pre-filling the cages markedly improved the histological fusion outcomes. In the baboon study, the beta-TCP plugs were completely osteointegrated at 6 months. For the group that used ceramic plugs impregnated with TGF-beta3, no incremental advantage was

  19. A new HaeIII polymorphism at the D21S13 locus.

    PubMed

    Pulst, S M; Korenberg, J R; Ren, M; Greenwald, J

    1990-10-01

    DNA markers in the pericentromeric region of human chromosome 21 have shown linkage to a gene for Familial Alzheimer disease (FAD; St. George Hyslop et al. 1987). The limited informativeness of probes for the loci D21S13 and D21S16 have hindered precise mapping of the FAD locus and analysis of non-allelic heterogeneity in FAD (Schellenberg et al. 1988; St. George-Hyslop et al. 1987). We recently described a new EcoRII polymorphism at the D21S13 locus that was very informative in a large FAD pedigree (Pulst et al. 1990a,b). We now report another polymorphism for the D21S13 locus that further increases the informativeness of this locus.

  20. Regulation of serum phosphate

    PubMed Central

    Lederer, Eleanor

    2014-01-01

    The regulation of serum phosphate, an acknowledged risk factor for chronic kidney disease and cardiovascular mortality, is poorly understood. The discovery of fibroblast growth factor 23 (FGF23) as a key regulator of renal phosphate handling and activation of vitamin D has revolutionized our comprehension of phosphate homeostasis. Through as yet undetermined mechanisms, circulating and dietary phosphate appear to have a direct effect on FGF23 release by bone cells that, in turn, causes renal phosphate excretion and decreases intestinal phosphate absorption through a decrease in vitamin D production. Thus, the two major phosphaturic hormones, PTH and FGF23, have opposing effects on vitamin D production, placing vitamin D at the nexus of phosphate homeostasis. While our understanding of phosphate homeostasis has advanced, the factors determining regulation of serum phosphate level remain enigmatic. Diet, time of day, season, gender, age and genetics have all been identified as significant contributors to serum phosphate level. The effects of these factors on serum phosphate have major implications for what is understood as ‘normal’ and for studies of phosphate homeostasis and metabolism. Moreover, other hormonal mediators such as dopamine, insulin-like growth factor, and angiotensin II also affect renal handling of phosphate. How the major hormone effects on phosphate handling are regulated and how the effect of these other factors are integrated to yield the measurable serum phosphate are only now beginning to be studied. PMID:24973411

  1. A new EcoRI polymorphism at the D21S13 locus.

    PubMed

    Pulst, S M; Korenberg, J R; Greenwald, J; Carbone, M

    1990-05-01

    The D21S13 locus has shown linkage to a gene for familial Alzheimer disease (FAD) on chromosome 21 (St. George-Hyslop et al. 1987). The limited informativeness of probes for this locus have hindered precise mapping of the FAD locus and analysis of nonallelic heterogeneity in FAD (Schellenberg et al. 1988; St. George-Hyslop et al. 1987). We describe a new EcoRI polymorphism at the D21S13 locus that may be useful for the further study of FAD families.

  2. Oxidation characteristics of Beta-21S in air in the temperature range 600 to 800 C

    NASA Technical Reports Server (NTRS)

    Wallace, Terryl A.; Clark, Ronald K.; Wiedemann, Karl E.

    1992-01-01

    The metastable beta-Ti alloy Beta-21S, Ti-15Mo-2.7Nb-3Al-0.2Si (weight percent), has been proposed as a candidate for use in metal matrix composites in future hypersonic vehicles. The present study investigated the oxidation behavior of Beta-21S over the temperature range 600 C to 800 C. Oxidation weight gain was evaluated using thermogravimetric analysis. Oxidized specimens were evaluated using x ray diffraction techniques, scanning electron microscopy, energy dispersive x ray analysis, and electron microprobe analysis to identify oxidation products and evaluate oxidation damage to the alloy.

  3. Microbial solubilization of phosphate

    DOEpatents

    Rogers, R.D.; Wolfram, J.H.

    1993-10-26

    A process is provided for solubilizing phosphate from phosphate containing ore by treatment with microorganisms which comprises forming an aqueous mixture of phosphate ore, microorganisms operable for solubilizing phosphate from the phosphate ore and maintaining the aqueous mixture for a period of time and under conditions operable to effect the microbial solubilization process. An aqueous solution containing soluble phosphorus can be separated from the reacted mixture by precipitation, solvent extraction, selective membrane, exchange resin or gravity methods to recover phosphate from the aqueous solution. 6 figures.

  4. Microbial solubilization of phosphate

    DOEpatents

    Rogers, Robert D.; Wolfram, James H.

    1993-01-01

    A process is provided for solubilizing phosphate from phosphate containing ore by treatment with microorganisms which comprises forming an aqueous mixture of phosphate ore, microorganisms operable for solubilizing phosphate from the phosphate ore and maintaining the aqueous mixture for a period of time and under conditions operable to effect the microbial solubilization process. An aqueous solution containing soluble phosphorous can be separated from the reacted mixture by precipitation, solvent extraction, selective membrane, exchange resin or gravity methods to recover phosphate from the aqueous solution.

  5. Glucose-6-phosphate dehydrogenase

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003671.htm Glucose-6-phosphate dehydrogenase test To use the sharing features on this page, please enable JavaScript. Glucose-6-phosphate dehydrogenase (G6PD) is a type of ...

  6. Uranium from phosphate ores

    SciTech Connect

    Hurst, F.J.

    1983-01-01

    The following topics are described briefly: the way phosphate fertilizers are made; how uranium is recovered in the phosphate industry; and how to detect covert uranium recovery operations in a phsophate plant.

  7. Zinc phosphate conversion coatings

    DOEpatents

    Sugama, T.

    1997-02-18

    Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate {alpha}-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal. 33 figs.

  8. Zinc phosphate conversion coatings

    DOEpatents

    Sugama, Toshifumi

    1997-01-01

    Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate .alpha.-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal.

  9. Phosphorus, phosphorous, and phosphate.

    PubMed

    Iheagwara, O Susan; Ing, Todd S; Kjellstrand, Carl M; Lew, Susie Q

    2013-10-01

    This article distinguishes the terms "phosphorus, phosphorous, and phosphate" which are frequently used interchangeably. We point out the difference between phosphorus and phosphate, with an emphasis on the unit of measure. Expressing a value without the proper name or unit of measure may lead to misunderstanding and erroneous conclusions. We indicate why phosphate must be expressed as milligrams per deciliter or millimoles per liter and not as milliequivalents per liter. Therefore, we elucidate the distinction among the terms "phosphorus, phosphorous, and phosphate" and the importance of saying precisely what one really means.

  10. CADMIUM PHOSPHATE GLASS

    DOEpatents

    Carpenter, H.W.; Johnson, P.D.

    1963-04-01

    A method of preparing a cadmium phosphate glass that comprises providing a mixture of solid inorganic compounds of cadmuim and phosphate having vaporizable components and heating the resulting composition to a temperature of at least 850 un. Concent 85% C is presented. (AEC)

  11. PHOSPHATE MANAGEMENT: FY2010 RESULTS OF PHOSPHATE PRECIPITATION TESTS

    SciTech Connect

    Hay, M.; King, W.

    2011-04-04

    The Phosphate Management program seeks to develop treatment options for caustic phosphate solutions resulting from the caustic leaching of the bismuth phosphate sludge. The SRNL subtask investigated the precipitation of phosphate salts from caustic solutions through addition of fluoride and by crystallization. The scoping tests examined the: precipitation of phosphate by the addition of sodium fluoride to form the sodium fluorophosphate double salt, Na{sub 7}F(PO{sub 4}){sub 2} {center_dot} 19H{sub 2}O, crystallization of phosphate by reducing the temperature of saturated phosphate solutions, and combinations of precipitation and crystallization. A simplified leachate simulant was used in the study produced by dissolving sodium phosphate in 1 M to 3.5 M sodium hydroxide solutions. The results show that all three processes; precipitation with sodium fluoride, crystallization, and combined precipitation/crystallization can be effective for removing large amounts of phosphate from solution. The combined process of precipitation/crystallization showed >90% removal of phosphate at all hydroxide concentrations when cooling a non-saturated phosphate solution from 65 C to 25 C. Based on the measured solubility of sodium phosphate, pH adjustment/caustic addition will also remove large amounts of phosphate from solution (>80%). For all three processes, the phosphate concentration in the caustic solution must be managed to keep the phosphate from becoming too concentrated and thereby potentially forming a solid mass of sodium phosphate after an effective phosphate removal process.

  12. Metal-phosphate binders

    SciTech Connect

    Howe, Beth Ann; Chaps-Cabrera, Jesus Guadalupe

    2009-05-12

    A metal-phosphate binder is provided. The binder may include an aqueous phosphoric acid solution, a metal-cation donor including a metal other than aluminum, an aluminum-cation donor, and a non-carbohydrate electron donor.

  13. Phosphate control in dialysis

    PubMed Central

    Cupisti, Adamasco; Gallieni, Maurizio; Rizzo, Maria Antonietta; Caria, Stefania; Meola, Mario; Bolasco, Piergiorgio

    2013-01-01

    Prevention and correction of hyperphosphatemia is a major goal of chronic kidney disease–mineral and bone disorder (CKD–MBD) management, achievable through avoidance of a positive phosphate balance. To this aim, optimal dialysis removal, careful use of phosphate binders, and dietary phosphate control are needed to optimize the control of phosphate balance in well-nourished patients on a standard three-times-a-week hemodialysis schedule. Using a mixed diffusive–convective hemodialysis tecniques, and increasing the number and/or the duration of dialysis tecniques are all measures able to enhance phosphorus (P) mass removal through dialysis. However, dialytic removal does not equal the high P intake linked to the high dietary protein requirement of dialysis patients; hence, the use of intestinal P binders is mandatory to reduce P net intestinal absorption. Unfortunately, even a large dose of P binders is able to bind approximately 200–300 mg of P on a daily basis, so it is evident that their efficacy is limited in the case of an uncontrolled dietary P load. Hence, limitation of dietary P intake is needed to reach the goal of neutral phosphate balance in dialysis, coupled to an adequate protein intake. To this aim, patients should be informed and educated to avoid foods that are naturally rich in phosphate and also processed food with P-containing preservatives. In addition, patients should preferentially choose food with a low P-to-protein ratio. For example, patients could choose egg white or protein from a vegetable source. Finally, boiling should be the preferred cooking procedure, because it induces food demineralization, including phosphate loss. The integrated approach outlined in this article should be actively adapted as a therapeutic alliance by clinicians, dieticians, and patients for an effective control of phosphate balance in dialysis patients. PMID:24133374

  14. Fatigue-life behavior and matrix fatigue crack spacing in unnotched SCS-6/Timetal 21S metal matrix composites

    NASA Technical Reports Server (NTRS)

    Ward, G. T.; Herrmann, D. J.; Hillberry, B. M.

    1993-01-01

    Fatigue tests of the SCS-6/Timetal 21S composite system were performed to characterize the fatigue behavior for unnotched conditions. The stress-life behavior of the unnotched (9/90)2s laminates was investigated for stress ratios of R = 0.1 and R = 0.3. The occurrence of matrix cracking was also examined in these specimens. This revealed multiple matrix crack initiation sites throughout the composite, as well as evenly spaced surface cracks along the length of the specimens. No difference in fatigue lives were observed for stress ratios of R = 0.1 and R = 0.3 when compared on a stress range basis. The unnotched SCS-6/Timetal 21S composites had shorter fatigue lives than the SCS-6/Ti-15-3 composites, however the neat Timetal 21S matrix material had a longer fatigue life than the neat Ti-15-3.

  15. Mechanical properties of coated titanium Beta-21S after exposure to air at 700 and 800 C

    NASA Technical Reports Server (NTRS)

    Wiedemann, Karl E.; Bird, R. Keith; Wallace, Terryl A.; Clark, Ronald K.

    1992-01-01

    Mechanical properties of Beta-21S (Ti-15Mo-3Al-2.7Nb-0.2Si, wt percent) with glass, aluminide, and glass-on-aluminide coatings less than 3-micron thick were studied. Coatings were deposited by sol-gel processing or electron-beam evaporation onto 4.5-mil (113-micron) thick Beta-21S sheet from which, after oxidizing in air at 700 or 800 C, tensile test specimens were machined. Plastic elongation was the most severely degraded of the tensile properties; the glass-on-aluminide coatings were the most effective in preventing degradation. It was found that oxygen trapping by forming oxides in the coating, and reactions between the coatings and the Beta-21S alloy played significant roles.

  16. Crack-bridging effects in notch fatigue of SCS-6/TIMETAL 21S composite laminates

    SciTech Connect

    Larsen, J.M.; Jira, J.R.; John, R.; Ashbaugh, N.E.

    1996-12-31

    Fatigue tests of middle-hole tension specimens of SCS-6/TIMETAL 21S composite (silicon-carbide fibers reinforcing a matrix of Ti-15Mo-2.6Nb-3Al-0.2Si alloy) were performed on three laminate architectures: unidirectional, cross ply, and quasi-isotropic. Specimens were tested over a range of stress levels, and fatigue damage was documented in situ by macrophotography and direct-current electric potential drop measurements. Typically, failure evolved by the formation of a few dominant cracks at the notch that propagated into the composite matrix and, in many instances, were substantially affected by unbroken fibers bridging the cracks. Fractographic and failure mode characterization revealed key differences in the effectiveness of crack bridging in the three laminates. A shear-lag crack-bridging model was shown to correlate crack growth data in the laminates based on an empirical value of fiber/matrix interfacial shear stress. Crack-bridging stress distributions were predicted using the shear lag model and verified by comparing the predicted crack opening displacement profiles with measurements made using a laser interferometric displacement gage system. Implications of the results are discussed with respect to the potential use of these materials in practical structural applications.

  17. Phosphate Mines, Jordan

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Jordan's leading industry and export commodities are phosphate and potash, ranked in the top three in the world. These are used to make fertilizer. The Jordan Phosphate Mines Company is the sole producer, having started operations in 1935. In addition to mining activities, the company produces phosphoric acid (for fertilizers, detergents, pharmaceuticals), diammonium phosphate (for fertilizer), sulphuric acid (many uses), and aluminum fluoride (a catalyst to make aluminum and magnesium).

    The image covers an area of 27.5 x 49.4 km, was acquired on September 17, 2005, and is located near 30.8 degrees north latitude, 36.1 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  18. Fundamentals of phosphate transfer.

    PubMed

    Kirby, Anthony J; Nome, Faruk

    2015-07-21

    Historically, the chemistry of phosphate transfer-a class of reactions fundamental to the chemistry of Life-has been discussed almost exclusively in terms of the nucleophile and the leaving group. Reactivity always depends significantly on both factors; but recent results for reactions of phosphate triesters have shown that it can also depend strongly on the nature of the nonleaving or "spectator" groups. The extreme stabilities of fully ionised mono- and dialkyl phosphate esters can be seen as extensions of the same effect, with one or two triester OR groups replaced by O(-). Our chosen lead reaction is hydrolysis-phosphate transfer to water: because water is the medium in which biological chemistry takes place; because the half-life of a system in water is an accepted basic index of stability; and because the typical mechanisms of hydrolysis, with solvent H2O providing specific molecules to act as nucleophiles and as general acids or bases, are models for reactions involving better nucleophiles and stronger general species catalysts. Not least those available in enzyme active sites. Alkyl monoester dianions compete with alkyl diester monoanions for the slowest estimated rates of spontaneous hydrolysis. High stability at physiological pH is a vital factor in the biological roles of organic phosphates, but a significant limitation for experimental investigations. Almost all kinetic measurements of phosphate transfer reactions involving mono- and diesters have been followed by UV-visible spectroscopy using activated systems, conveniently compounds with good leaving groups. (A "good leaving group" OR* is electron-withdrawing, and can be displaced to generate an anion R*O(-) in water near pH 7.) Reactivities at normal temperatures of P-O-alkyl derivatives-better models for typical biological substrates-have typically had to be estimated: by extended extrapolation from linear free energy relationships, or from rate measurements at high temperatures. Calculation is free

  19. Ribose-5-phosphate isomerase and ribulose-5-phosphate kinase show apparent specificity for a specific ribulose 5-phosphate species.

    PubMed

    Anderson, L E

    1987-02-01

    Ribose-5-phosphate isomerase and ribulose-5-phosphate kinase appear to show specificity for a particular ribulose 5-phosphate species. The effect of this specificity will be channeling of ribulose 5-phosphate from the isomerase to the kinase during photosynthesis.

  20. Domestic phosphate deposits

    USGS Publications Warehouse

    McKelvey, V.E.; Cathcart, J.B.; Altschuler, Z.S.; Swanson, R.W.; Lutz, Katherine

    1953-01-01

    Most of the worlds phosphate deposits can be grouped into six types: 1) igneous apatite deposits; 2) marine phosphorites; 3) residual phosphorites; 4) river pebble deposits; 5) phosphatized rock; and 6) guano. The igneous apatites and marine phosphorites form deposits measurable in millions or billions of tons; the residual deposits are measurable in thousands or millions; and the other types generally only in thousands of tons. Igneous apatite deposits have been mined on a small scale in New York, New Jersey, and Virginia. Marine phosphorites have been mined in Montana, Idaho, Utah, Wyoming, Arkansas, Tennessee, North Carolina, South Carolina, Georgia, and Florida. Residual phosphorites have been mined in Tennessee, Pennsylvania, and Florida. River pebble has been produced in South Carolina and Florida; phosphatized rock in Tennessee and Florida; and guano in New Mexico and Texas. Present production is limited almost entirely to Florida, Tennessee, Montana, Idaho, and Wyoming. Incomplete but recently partly revised estimates indicate the presence of about 5 billion tons of phosphate deposits in the United States that is minable under present economic conditions. Deposits too lean in quality or thickness to compete with those in the western and southeastern fields probably contain tens of billions of tons.

  1. 21 CFR 184.1434 - Magnesium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Magnesium phosphate. 184.1434 Section 184.1434... Listing of Specific Substances Affirmed as GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes both magnesium phosphate, dibasic, and magnesium phosphate, tribasic. Magnesium phosphate,...

  2. 21 CFR 184.1434 - Magnesium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Magnesium phosphate. 184.1434 Section 184.1434... Listing of Specific Substances Affirmed as GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes both magnesium phosphate, dibasic, and magnesium phosphate, tribasic. Magnesium phosphate,...

  3. 21 CFR 184.1434 - Magnesium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Magnesium phosphate. 184.1434 Section 184.1434... Listing of Specific Substances Affirmed as GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes both magnesium phosphate, dibasic, and magnesium phosphate, tribasic. Magnesium phosphate,...

  4. 21 CFR 184.1434 - Magnesium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Magnesium phosphate. 184.1434 Section 184.1434... GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes both magnesium phosphate, dibasic, and magnesium phosphate, tribasic. Magnesium phosphate, dibasic (MgHPO4·3H2O, CAS Reg. No....

  5. 21 CFR 184.1434 - Magnesium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium phosphate. 184.1434 Section 184.1434 Food... Specific Substances Affirmed as GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes both magnesium phosphate, dibasic, and magnesium phosphate, tribasic. Magnesium phosphate, dibasic...

  6. Biomediated continuous release phosphate fertilizer

    DOEpatents

    Goldstein, Alan H.; Rogers, Robert D.

    1999-01-01

    A composition is disclosed for providing phosphate fertilizer to the root zone of plants. The composition comprises a microorganism capable of producing and secreting a solubilization agent, a carbon source for providing raw material for the microorganism to convert into the solubilization agent, and rock phosphate ore for providing a source of insoluble phosphate that is solubilized by the solubilization agent and released as soluble phosphate. The composition is provided in a physical form, such as a granule, that retains the microorganism, carbon source, and rock phosphate ore, but permits water and soluble phosphate to diffuse into the soil. A method of using the composition for providing phosphate fertilizer to plants is also disclosed.

  7. Biomediated continuous release phosphate fertilizer

    DOEpatents

    Goldstein, A.H.; Rogers, R.D.

    1999-06-15

    A composition is disclosed for providing phosphate fertilizer to the root zone of plants. The composition comprises a microorganism capable of producing and secreting a solubilization agent, a carbon source for providing raw material for the microorganism to convert into the solubilization agent, and rock phosphate ore for providing a source of insoluble phosphate that is solubilized by the solubilization agent and released as soluble phosphate. The composition is provided in a physical form, such as a granule, that retains the microorganism, carbon source, and rock phosphate ore, but permits water and soluble phosphate to diffuse into the soil. A method of using the composition for providing phosphate fertilizer to plants is also disclosed. 13 figs.

  8. Dysregulation of phosphate metabolism and conditions associated with phosphate toxicity

    PubMed Central

    Brown, Ronald B; Razzaque, Mohammed S

    2015-01-01

    Phosphate homeostasis is coordinated and regulated by complex cross-organ talk through delicate hormonal networks. Parathyroid hormone (PTH), secreted in response to low serum calcium, has an important role in maintaining phosphate homeostasis by influencing renal synthesis of 1,25-dihydroxyvitamin D, thereby increasing intestinal phosphate absorption. Moreover, PTH can increase phosphate efflux from bone and contribute to renal phosphate homeostasis through phosphaturic effects. In addition, PTH can induce skeletal synthesis of another potent phosphaturic hormone, fibroblast growth factor 23 (FGF23), which is able to inhibit renal tubular phosphate reabsorption, thereby increasing urinary phosphate excretion. FGF23 can also fine-tune vitamin D homeostasis by suppressing renal expression of 1-alpha hydroxylase (1α(OH)ase). This review briefly discusses how FGF23, by forming a bone–kidney axis, regulates phosphate homeostasis, and how its dysregulation can lead to phosphate toxicity that induces widespread tissue injury. We also provide evidence to explain how phosphate toxicity related to dietary phosphorus overload may facilitate incidence of noncommunicable diseases including kidney disease, cardiovascular disease, cancers and skeletal disorders. PMID:26131357

  9. Dysregulation of phosphate metabolism and conditions associated with phosphate toxicity.

    PubMed

    Brown, Ronald B; Razzaque, Mohammed S

    2015-01-01

    Phosphate homeostasis is coordinated and regulated by complex cross-organ talk through delicate hormonal networks. Parathyroid hormone (PTH), secreted in response to low serum calcium, has an important role in maintaining phosphate homeostasis by influencing renal synthesis of 1,25-dihydroxyvitamin D, thereby increasing intestinal phosphate absorption. Moreover, PTH can increase phosphate efflux from bone and contribute to renal phosphate homeostasis through phosphaturic effects. In addition, PTH can induce skeletal synthesis of another potent phosphaturic hormone, fibroblast growth factor 23 (FGF23), which is able to inhibit renal tubular phosphate reabsorption, thereby increasing urinary phosphate excretion. FGF23 can also fine-tune vitamin D homeostasis by suppressing renal expression of 1-alpha hydroxylase (1α(OH)ase). This review briefly discusses how FGF23, by forming a bone-kidney axis, regulates phosphate homeostasis, and how its dysregulation can lead to phosphate toxicity that induces widespread tissue injury. We also provide evidence to explain how phosphate toxicity related to dietary phosphorus overload may facilitate incidence of noncommunicable diseases including kidney disease, cardiovascular disease, cancers and skeletal disorders. PMID:26131357

  10. Total Structure Determination of Au21(S-Adm)15 and Geometrical/Electronic Structure Evolution of Thiolated Gold Nanoclusters.

    PubMed

    Chen, Shuang; Xiong, Lin; Wang, Shuxin; Ma, Zhongyun; Jin, Shan; Sheng, Hongting; Pei, Yong; Zhu, Manzhou

    2016-08-31

    The larger size gold nanoparticles typically adopt a face-centered cubic (fcc) atomic packing, while in the ultrasmall nanoclusters the packing styles of Au atoms are diverse, including fcc, hexagonal close packing (hcp), and body-centered cubic (bcc), depending on the ligand protection. The possible conversion between these packing structures is largely unknown. Herein, we report the growth of a new Au21(S-Adm)15 nanocluster (S-Adm = adamantanethiolate) from Au18(SR)14 (SR = cyclohexylthiol), with the total structure determined by X-ray crystallography. It is discovered that the hcp Au9-core in Au18(SR)14 is transformed to a fcc Au10-core in Au21(S-Adm)15. Combining with density functional theory (DFT) calculations, we provide critical information about the growth mechanism (geometrical and electronic structure) and the origin of fcc-structure formation for the thiolate-protected gold nanoclusters. PMID:27552520

  11. Solubilization of insoluble phosphates by thermophilic fungi.

    PubMed

    Singh, C P; Mishra, M M; Yadav, K S

    1980-01-01

    The solubilization of tricalcium phosphate and rock phosphate and assimilation of solubilized P by thermophilic fungi isolated from compost were studied. The solubilization of tricalcium phosphate was greater than that of rock phosphate on inoculation with fungi in liquid medium, but growth of most of the fungi was greater in rock phosphate. Torula thermophila solubilized tricalcium phosphate maximally. There was solubilization of rock phosphate in semi-solid lignocellulose medium by Aspergillus fumigatus.

  12. Inositol phosphates in the environment.

    PubMed Central

    Turner, Benjamin L; Papházy, Michael J; Haygarth, Philip M; McKelvie, Ian D

    2002-01-01

    The inositol phosphates are a group of organic phosphorus compounds found widely in the natural environment, but that represent the greatest gap in our understanding of the global phosphorus cycle. They exist as inositols in various states of phosphorylation (bound to between one and six phosphate groups) and isomeric forms (e.g. myo, D-chiro, scyllo, neo), although myo-inositol hexakisphosphate is by far the most prevalent form in nature. In terrestrial environments, inositol phosphates are principally derived from plants and accumulate in soils to become the dominant class of organic phosphorus compounds. Inositol phosphates are also present in large amounts in aquatic environments, where they may contribute to eutrophication. Despite the prevalence of inositol phosphates in the environment, their cycling, mobility and bioavailability are poorly understood. This is largely related to analytical difficulties associated with the extraction, separation and detection of inositol phosphates in environmental samples. This review summarizes the current knowledge of inositol phosphates in the environment and the analytical techniques currently available for their detection in environmental samples. Recent advances in technology, such as the development of suitable chromatographic and capillary electrophoresis separation techniques, should help to elucidate some of the more pertinent questions regarding inositol phosphates in the natural environment. PMID:12028785

  13. Light weight phosphate cements

    DOEpatents

    Wagh, Arun S.; Natarajan, Ramkumar,; Kahn, David

    2010-03-09

    A sealant having a specific gravity in the range of from about 0.7 to about 1.6 for heavy oil and/or coal bed methane fields is disclosed. The sealant has a binder including an oxide or hydroxide of Al or of Fe and a phosphoric acid solution. The binder may have MgO or an oxide of Fe and/or an acid phosphate. The binder is present from about 20 to about 50% by weight of the sealant with a lightweight additive present in the range of from about 1 to about 10% by weight of said sealant, a filler, and water sufficient to provide chemically bound water present in the range of from about 9 to about 36% by weight of the sealant when set. A porous ceramic is also disclosed.

  14. Templated, layered manganese phosphate

    DOEpatents

    Thoma, Steven G.; Bonhomme, Francois R.

    2004-08-17

    A new crystalline maganese phosphate composition having an empirical formula: O). The compound was determined to crystallize in the trigonal space group P-3c1 with a=8.8706(4) .ANG., c=26.1580(2) .ANG., and V (volume)=1783 .ANG..sup.3. The structure consists of sheets of corner sharing Mn(II)O.sub.4 and PO.sub.4 tetrahedra with layers of (H.sub.3 NCH.sub.2 CH.sub.2).sub.3 N and water molecules in-between. The pronated (H.sub.3 NCH.sub.2 CH.sub.2).sub.3 N molecules provide charge balancing for the inorganic sheets. A network of hydrogen bonds between water molecules and the inorganic sheets holds the structure together.

  15. Phosphate nutrition: improving low-phosphate tolerance in crops.

    PubMed

    López-Arredondo, Damar Lizbeth; Leyva-González, Marco Antonio; González-Morales, Sandra Isabel; López-Bucio, José; Herrera-Estrella, Luis

    2014-01-01

    Phosphorus is an essential nutrient that is required for all major developmental processes and reproduction in plants. It is also a major constituent of the fertilizers required to sustain high-yield agriculture. Levels of phosphate--the only form of phosphorus that can be assimilated by plants--are suboptimal in most natural and agricultural ecosystems, and when phosphate is applied as fertilizer in soils, it is rapidly immobilized owing to fixation and microbial activity. Thus, cultivated plants use only approximately 20-30% of the applied phosphate, and the rest is lost, eventually causing water eutrophication. Recent advances in the understanding of mechanisms by which wild and cultivated species adapt to low-phosphate stress and the implementation of alternative bacterial pathways for phosphorus metabolism have started to allow the design of more effective breeding and genetic engineering strategies to produce highly phosphate-efficient crops, optimize fertilizer use, and reach agricultural sustainability with a lower environmental cost. In this review, we outline the current advances in research on the complex network of plant responses to low-phosphorus stress and discuss some strategies used to manipulate genes involved in phosphate uptake, remobilization, and metabolism to develop low-phosphate-tolerant crops, which could help in designing more efficient crops.

  16. 21 CFR 520.823 - Erythromycin phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    .... (a) Specifications. Erythromycin phosphate is the phosphate salt of the antibiotic substance produced by the growth of Streptomyces erythreus or the same antibiotic substance produced by any other...

  17. 21 CFR 520.823 - Erythromycin phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .... (a) Specifications. Erythromycin phosphate is the phosphate salt of the antibiotic substance produced by the growth of Streptomyces erythreus or the same antibiotic substance produced by any other...

  18. 21 CFR 520.823 - Erythromycin phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    .... (a) Specifications. Erythromycin phosphate is the phosphate salt of the antibiotic substance produced by the growth of Streptomyces erythreus or the same antibiotic substance produced by any other...

  19. 21 CFR 520.823 - Erythromycin phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .... (a) Specifications. Erythromycin phosphate is the phosphate salt of the antibiotic substance produced by the growth of Streptomyces erythreus or the same antibiotic substance produced by any other...

  20. 21 CFR 520.823 - Erythromycin phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    .... (a) Specifications. Erythromycin phosphate is the phosphate salt of the antibiotic substance produced by the growth of Streptomyces erythreus or the same antibiotic substance produced by any other...

  1. Quality control in production of suspensions from solid ammonium phosphates (monoammonium phosphate and diammonium phosphate). [Monoammonium phosphate; diammonium phosphate

    SciTech Connect

    Achorn, F.P.; Balay, H.L.

    1982-01-01

    Suspensions of good quality can be produced from MAP and DAP. Suspension quality depends on the amount of impurities in the ammonium phosphate solids used. Tests have shown that adding ammonium fluoride helps lower viscosity of suspensions containing a considerable amount of impurities. Also, adding polyphosphates (such as 10-34-0, 9-32-0, and 11-37-0) as a source of part of the P/sub 2/O/sub 5/ (6 to 15% polyphosphate in the product) helps to produce a suspension that has excellent storage characteristics. When the polyphosphate content of the product (11-33-0 suspension) is between 10 and 15% it usually will not solidify during cold weather storage. Freight and production costs of granular ammonium phosphates are relatively low compared to other sources of P/sub 2/O/sub 5/ for the fluid fertilizer market; therefore, using MAP and DAP to produce suspensions is expected to continue to grow in popularity. 2 refs., 7 figs., 1 tab.

  2. Toxicological review of inorganic phosphates.

    PubMed

    Weiner, M L; Salminen, W F; Larson, P R; Barter, R A; Kranetz, J L; Simon, G S

    2001-08-01

    Inorganic phosphate salts are widely used as food ingredients and in a variety of commercial applications. The United States Food and Drug Administration (FDA) considers inorganic phosphates "Generally Recognized As Safe" (GRAS) (FDA, 1973a, 1979) [FDA: Food and Drug Administration 1973a. GRAS (Generally Recognized as Safe) food ingredients-phosphates. NTIS PB-221-224, FDA, Food and Drug Administration, 1979. Phosphates; Proposed Affirmation of and Deletion From GRAS Status as Direct and Human Food Ingredients. Federal Register 44 (244). 74845-74857, 18 December (1979)] and the European Union (EU) allows inorganic phosphates to be added directly to food (EU Directive 95/2/EC as amended by 98/72/EC). In this review, data on the acute, subchronic and chronic toxicity, genotoxicity, teratogenicity and reproductive toxicity from the published literature and from unpublished studies by the manufacturers are reviewed. Based on the toxicity data and similar chemistry, the inorganic phosphates can be separated into four major classes, consisting of monovalent salts, divalent salts, ammonium salts and aluminum salts. The proposed classification scheme supports the use of toxicity data from one compound to assess the toxicity of another compound in the same class. However, in the case of eye and skin irritation, the proposed classification scheme cannot be used because a wide range of responses exists within each class. Therefore, the eye and skin hazards associated with an individual inorganic phosphate should be assessed on a chemical-by-chemical basis. A large amount of toxicity data exists for all four classes of inorganic phosphates. The large and comprehensive database allows an accurate assessment of the toxicity of each class of inorganic phosphate. Overall, all four classes of inorganic phosphates exhibit low oral, inhalation and dermal toxicities. Based on these data, humans are unlikely to experience adverse effects when the daily phosphorus consumption remains

  3. Phosphate transport and sensing in Saccharomyces cerevisiae.

    PubMed Central

    Wykoff, D D; O'Shea, E K

    2001-01-01

    Cellular metabolism depends on the appropriate concentration of intracellular inorganic phosphate; however, little is known about how phosphate concentrations are sensed. The similarity of Pho84p, a high-affinity phosphate transporter in Saccharomyces cerevisiae, to the glucose sensors Snf3p and Rgt2p has led to the hypothesis that Pho84p is an inorganic phosphate sensor. Furthermore, pho84Delta strains have defects in phosphate signaling; they constitutively express PHO5, a phosphate starvation-inducible gene. We began these studies to determine the role of phosphate transporters in signaling phosphate starvation. Previous experiments demonstrated a defect in phosphate uptake in phosphate-starved pho84Delta cells; however, the pho84Delta strain expresses PHO5 constitutively when grown in phosphate-replete media. We determined that pho84Delta cells have a significant defect in phosphate uptake even when grown in high phosphate media. Overexpression of unrelated phosphate transporters or a glycerophosphoinositol transporter in the pho84Delta strain suppresses the PHO5 constitutive phenotype. These data suggest that PHO84 is not required for sensing phosphate. We further characterized putative phosphate transporters, identifying two new phosphate transporters, PHO90 and PHO91. A synthetic lethal phenotype was observed when five phosphate transporters were inactivated, and the contribution of each transporter to uptake in high phosphate conditions was determined. Finally, a PHO84-dependent compensation response was identified; the abundance of Pho84p at the plasma membrane increases in cells that are defective in other phosphate transporters. PMID:11779791

  4. Uranium endowments in phosphate rock.

    PubMed

    Ulrich, Andrea E; Schnug, Ewald; Prasser, Horst-Michael; Frossard, Emmanuel

    2014-04-15

    This study seeks to identify and specify the components that make up the prospects of U recovery from phosphate rock. A systems approach is taken. The assessment includes i) reviewing past recovery experience and lessons learned; ii) identifying factors that determine recovery; and iii) establishing a contemporary evaluation of U endowments in phosphate rock reserves, as well as the available and recoverable amounts from phosphate rock and phosphoric acid production. We find that in the past, recovery did not fulfill its potential and that the breakup of the Soviet Union worsened then-favorable recovery market conditions in the 1990s. We find that an estimated 5.7 million tU may be recoverable from phosphate rock reserves. In 2010, the recoverable tU from phosphate rock and phosphoric acid production may have been 15,000 tU and 11,000 tU, respectively. This could have filled the world U supply-demand gap for nuclear energy production. The results suggest that the U.S., Morocco, Tunisia, and Russia would be particularly well-suited to recover U, taking infrastructural considerations into account. We demonstrate future research needs, as well as sustainability orientations. We conclude that in order to promote investment and production, it seems necessary to establish long-term contracts at guaranteed prices, ensuring profitability for phosphoric acid producers. PMID:24556272

  5. Uranium endowments in phosphate rock.

    PubMed

    Ulrich, Andrea E; Schnug, Ewald; Prasser, Horst-Michael; Frossard, Emmanuel

    2014-04-15

    This study seeks to identify and specify the components that make up the prospects of U recovery from phosphate rock. A systems approach is taken. The assessment includes i) reviewing past recovery experience and lessons learned; ii) identifying factors that determine recovery; and iii) establishing a contemporary evaluation of U endowments in phosphate rock reserves, as well as the available and recoverable amounts from phosphate rock and phosphoric acid production. We find that in the past, recovery did not fulfill its potential and that the breakup of the Soviet Union worsened then-favorable recovery market conditions in the 1990s. We find that an estimated 5.7 million tU may be recoverable from phosphate rock reserves. In 2010, the recoverable tU from phosphate rock and phosphoric acid production may have been 15,000 tU and 11,000 tU, respectively. This could have filled the world U supply-demand gap for nuclear energy production. The results suggest that the U.S., Morocco, Tunisia, and Russia would be particularly well-suited to recover U, taking infrastructural considerations into account. We demonstrate future research needs, as well as sustainability orientations. We conclude that in order to promote investment and production, it seems necessary to establish long-term contracts at guaranteed prices, ensuring profitability for phosphoric acid producers.

  6. Dissolution of phosphate matrices based on the thorium phosphate diphosphate

    NASA Astrophysics Data System (ADS)

    Dacheux, N.; Thomas, A. C.; Brandel, V.; Genet, M.

    2000-07-01

    Several authors have reported the use of phosphate matrices like apatites, monazites or NZP for the immobilization of actinides coming from an advanced reprocessing or for the final disposal of the excess plutonium from dismantled nuclear weapons. The thorium phosphate diphosphate Th4(PO4)4P2O7 (namely TPD) was also proposed for this purpose. Indeed, its structure allows the replacement of large amounts of tetravalent actinides like uranium, neptunium or plutonium leading to the obtention of solid solutions. The maximum weight loading was estimated to be equal to about 48% for uranium, 33% for neptunium and 26% for plutonium.

  7. Phosphate-a poison for humans?

    PubMed

    Komaba, Hirotaka; Fukagawa, Masafumi

    2016-10-01

    Maintenance of phosphate balance is essential for life, and mammals have developed a sophisticated system to regulate phosphate homeostasis over the course of evolution. However, due to the dependence of phosphate elimination on the kidney, humans with decreased kidney function are likely to be in a positive phosphate balance. Phosphate excess has been well recognized as a critical factor in the pathogenesis of mineral and bone disorders associated with chronic kidney disease, but recent investigations have also uncovered toxic effects of phosphate on the cardiovascular system and the aging process. Compelling evidence also suggests that increased fibroblastic growth factor 23 and parathyroid hormone levels in response to a positive phosphate balance contribute to adverse clinical outcomes. These insights support the current practice of managing serum phosphate in patients with advanced chronic kidney disease, although definitive evidence of these effects is lacking. Given the potential toxicity of excess phosphate, the general population may also be viewed as a target for phosphate management. However, the widespread implementation of dietary phosphate intervention in the general population may not be warranted due to the limited impact of increased phosphate intake on mineral metabolism and clinical outcomes. Nonetheless, the increasing incidence of kidney disease or injury in our aging society emphasizes the potential importance of this issue. Further work is needed to more completely characterize phosphate toxicity and to establish the optimal therapeutic strategy for managing phosphate in patients with chronic kidney disease and in the general population. PMID:27282935

  8. Process for producing granular diammonium phosphate

    SciTech Connect

    Fairchild, W.D.

    1988-05-17

    A process for the production of solid granular diammonium phosphate is described comprising: reacting anhydrous ammonia with phosphoric acid in a reactor to form a partially reacted slurry of monoammonium phosphate and diammonium phosphate; pumping the slurry to a granulator-reactor and further reacting the slurry with anhydrous ammonia to form a solid granular diammonium phosphate mixture having a particle range size consisting of undersize, oversize and product; drying the solid granular diammonium phosphate mixture in a dryer; dividing the dried solid granular diammonium phosphate mixture being discharged from the dryer into a first portion and a second portion; diverting and feeding the first portion of the dried granular diammonium phosphate mixture back to the granulator-reactor; feeding the second portion of dried granular diammonium phosphate mixture to a classifying means consisting of a set of screens including an oversize screen and a product screen set to a narrow size separation to separate the mixture of the solid granular diammonium phosphate into undersize, oversize and product solid granular diammonium phosphate; milling the oversize granular diammonium phosphate; recycling to the granular-reactor the milled oversized granular diammonium phosphate and the undersized granular particles obtained during the classifying of the solid granular diammonium phosphate mixture; and collecting the desired product granular particle thereby enhancing the production of a narrow range of granular diammonium phosphate particle size distribution within a broad range of particle size distribution.

  9. Detergent phosphate bans and eutrophication

    SciTech Connect

    Lee, G.F.; Jones, R.A.

    1986-04-01

    The Vollenweider-OECD eutrophication model has been expanded to approximately 400 lakes. It is possible to make a quantitative prediction of the effects of a detergent phosphate ban and thereby to ascertain the potential benefits of such a ban. In order to assess the effect of a detergent phosphate ban on water quality it is necessary to know the percentage of phosphorus in the domestic waste water that enters the water body, either directly or indirectly, and the percentage of the total phosphorus load that is derived from domestic wastewater. Although detergent phosphate bans generally will not result in an overall improvement to water quality, there may be some situations in which eutrophication-related water quality would be improved by a ban. 8 references, 1 figure, 1 table.

  10. [Phosphate metabolism and iron deficiency].

    PubMed

    Yokoyama, Keitaro

    2016-02-01

    Autosomal dominant hypophosphatemic rickets(ADHR)is caused by gain-of-function mutations in FGF23 that prevent its proteolytic cleavage. Fibroblast growth factor 23(FGF23)is a hormone that inhibits renal phosphate reabsorption and 1,25-dihydroxyvitamin D biosynthesis. Low iron status plays a role in the pathophysiology of ADHR. Iron deficiency is an environmental trigger that stimulates FGF23 expression and hypophosphatemia in ADHR. It was reported that FGF23 elevation in patients with CKD, who are often iron deficient. In patients with nondialysis-dependent CKD, treatment with ferric citrate hydrate resulted in significant reductions in serum phosphate and FGF23.

  11. Effect of temperature on fiber/matrix interface sliding stress in SCS-6/Timetal{reg_sign}21S

    SciTech Connect

    Hutson, A.; John, R.; Jira, J.

    1999-02-05

    Many potential applications exist for components manufactured using Titanium Matrix Composites (TMC) because of the high specific strength and stiffness the material exhibits at elevated temperature. Several methods have been employed to determine or deduce the fiber/matrix interfacial shear stress, {tau}. Fiber push-out and pull-out techniques have been used to measure {tau}, but efforts to apply these values to accurate fatigue crack growth prediction have failed. Other methods include determination of {tau} as a fitting parameter based on correlation with parameters measured during fatigue crack growth tests. A common approach is to calibrate {tau} using the crack length versus cycles data (a-N) from a fully bridged crack growth test at a given applied stress. Subsequently, this value of {tau} has been shown to have predictive capabilities for crack opening displacements (COD), slip lengths, and a-N at other stress levels and volume fractions. Application of fiber bridging models to components under service loading conditions requires {tau} as a function of temperature over a wide range of crack lengths. Hence, this paper discusses the determination of {tau} as a function of temperature from COD measured in situ during crack growth along long fully-bridged cracks in SCS-6/TIMETAL{reg_sign}21S. Two commonly used shear lag models were evaluated during this study.

  12. In-Vitro Biocompatibility Studies of Plasma-Nitrided Titanium Alloy β-21S Using Fibroblast Cells

    NASA Astrophysics Data System (ADS)

    Mohan, L.; Raja, M. D.; Uma, T. S.; Rajendran, N.; Anandan, C.

    2016-04-01

    In the present work, titanium alloy β-21S was nitrided in a low-pressure RF plasma with 100% nitrogen and 20% hydrogen-diluted nitrogen at 800 °C for 4 h and the samples were evaluated for in-vitro biocompatibility by using NIH 3T3 fibroblast cell line. Cellular behavior was evaluated in terms of cell morphology and its viability. FESEM was exploited to observe the morphology of the cells fixed over the surface of the implant. Fibroblasts were seemed to be well distributed over the surface with its characteristic spindle-like shape. Over all, the results indicate that nitriding provided a compatible surface for cell attachment and cell growth. Cell viability and proliferation was assessed by using standard MTT assay. Compared with substrate, the nitrided samples exhibited high-percentage cell viability demonstrating their increased biocompatibility. In addition, the nitrided samples facilitate bone-like apatite formation and exhibited a gradual increase of apatite formation after immersion in Hanks' solution.

  13. Photorelease of phosphates: Mild methods for protecting phosphate derivatives

    PubMed Central

    Senadheera, Sanjeewa N; Yousef, Abraham L

    2014-01-01

    Summary We have developed a new photoremovable protecting group for caging phosphates in the near UV. Diethyl 2-(4-hydroxy-1-naphthyl)-2-oxoethyl phosphate (14a) quantitatively releases diethyl phosphate upon irradiation in aq MeOH or aq MeCN at 350 nm, with quantum efficiencies ranging from 0.021 to 0.067 depending on the solvent composition. The deprotection reactions originate from the triplet excited state, are robust under ambient conditions and can be carried on to 100% conversion. Similar results were found with diethyl 2-(4-methoxy-1-naphthyl)-2-oxoethyl phosphate (14b), although it was significantly less efficient compared with 14a. A key step in the deprotection reaction in aq MeOH is considered to be a Favorskii rearrangement of the naphthyl ketone motif of 14a,b to naphthylacetate esters 25 and 26. Disruption of the ketone-naphthyl ring conjugation significantly shifts the photoproduct absorption away from the effective incident wavelength for decaging of 14, driving the reaction to completion. The Favorskii rearrangement does not occur in aqueous acetonitrile although diethyl phosphate is released. Other substitution patterns on the naphthyl or quinolin-5-yl core, such as the 2,6-naphthyl 10 or 8-benzyloxyquinolin-5-yl 24 platforms, also do not rearrange by aryl migration upon photolysis and, therefore, do not proceed to completion. The 2,6-naphthyl ketone platform instead remains intact whereas the quinolin-5-yl ketone fragments to a much more complex, highly absorbing reaction mixture that competes for the incident light. PMID:25246963

  14. 21 CFR 582.5434 - Magnesium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5434 Magnesium phosphate. (a) Product. Magnesium phosphate (di- and tribasic)....

  15. 21 CFR 582.5301 - Ferric phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5301 Ferric phosphate. (a) Product. Ferric phosphate. (b) Conditions of use....

  16. 21 CFR 582.5778 - Sodium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic)....

  17. 21 CFR 582.5217 - Calcium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  18. 21 CFR 582.5301 - Ferric phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5301 Ferric phosphate. (a) Product. Ferric phosphate. (b) Conditions of use....

  19. 21 CFR 582.5217 - Calcium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  20. 21 CFR 582.5778 - Sodium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic)....

  1. 21 CFR 582.5301 - Ferric phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5301 Ferric phosphate. (a) Product. Ferric phosphate. (b) Conditions of use....

  2. 21 CFR 582.5301 - Ferric phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5301 Ferric phosphate. (a) Product. Ferric phosphate. (b) Conditions of use....

  3. 21 CFR 582.5301 - Ferric phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5301 Ferric phosphate. (a) Product. Ferric phosphate. (b) Conditions of use....

  4. 21 CFR 582.5434 - Magnesium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5434 Magnesium phosphate. (a) Product. Magnesium phosphate (di- and tribasic)....

  5. 21 CFR 582.5217 - Calcium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  6. 21 CFR 582.5217 - Calcium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  7. 21 CFR 582.5434 - Magnesium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5434 Magnesium phosphate. (a) Product. Magnesium phosphate (di- and tribasic)....

  8. 21 CFR 582.5778 - Sodium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic)....

  9. 21 CFR 582.5217 - Calcium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  10. 21 CFR 582.5434 - Magnesium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5434 Magnesium phosphate. (a) Product. Magnesium phosphate (di- and tribasic)....

  11. 21 CFR 582.5434 - Magnesium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5434 Magnesium phosphate. (a) Product. Magnesium phosphate (di- and tribasic)....

  12. Genetics Home Reference: glucose phosphate isomerase deficiency

    MedlinePlus

    ... Me Understand Genetics Home Health Conditions GPI deficiency glucose phosphate isomerase deficiency Enable Javascript to view the ... boxes. Download PDF Open All Close All Description Glucose phosphate isomerase (GPI) deficiency is an inherited disorder ...

  13. Phosphate bonding to goethite and pyrolusite surfaces

    USGS Publications Warehouse

    Weiner, Eugene R.; Goldberg, M.C.; Boymel, P.M.

    1984-01-01

    Fourier transform infrared (FTIR) spectra were obtained from pure and phosphated goethite (??-FeOOH), and pyrolusite (MnO2). The nature of the phosphate-surface bond was determined to be binuclear for goethite and bidentate for pyrolusite.

  14. 21 CFR 184.1301 - Ferric phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Specific Substances Affirmed as GRAS § 184.1301 Ferric phosphate. (a) Ferric phosphate (ferric orthophosphate, iron (III) phosphate, FePO4·xH2O, CAS Reg. No. 10045-86-0) is an odorless, yellowish-white to... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ferric phosphate. 184.1301 Section 184.1301...

  15. Sintering of calcium phosphate bioceramics.

    PubMed

    Champion, E

    2013-04-01

    Calcium phosphate ceramics have become of prime importance for biological applications in the field of bone tissue engineering. This paper reviews the sintering behaviour of these bioceramics. Conventional pressureless sintering of hydroxyapatite, Ca10(PO4)6(OH)2, a reference compound, has been extensively studied. Its physico-chemistry is detailed. It can be seen as a competition between two thermally activated phenomena that proceed by solid-state diffusion of matter: densification and grain growth. Usually, the objective is to promote the first and prevent the second. Literature data are analysed from sintering maps (i.e. grain growth vs. densification). Sintering trajectories of hydroxyapatite produced by conventional pressureless sintering and non-conventional techniques, including two-step sintering, liquid phase sintering, hot pressing, hot isostatic pressing, ultrahigh pressure, microwave and spark plasma sintering, are presented. Whatever the sintering technique may be, grain growth occurs mainly during the last step of sintering, when the relative bulk density reaches 95% of the maximum value. Though often considered very advantageous, most assisted sintering techniques do not appear very superior to conventional pressureless sintering. Sintering of tricalcium phosphate or biphasic calcium phosphates is also discussed. The chemical composition of calcium phosphate influences the behaviour. Similarly, ionic substitutions in hydroxyapatite or in tricalcium phosphate create lattice defects that modify the sintering rate. Depending on their nature, they can either accelerate or slow down the sintering rate. The thermal stability of compounds at the sintering temperature must also be taken into account. Controlled atmospheres may be required to prevent thermal decomposition, and flash sintering techniques, which allow consolidation at low temperature, can be helpful. PMID:23212081

  16. 21 CFR 582.1778 - Sodium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Sodium phosphate. 582.1778 Section 582.1778 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic)....

  17. 21 CFR 182.6778 - Sodium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium phosphate. 182.6778 Section 182.6778 Food... HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Sequestrants 1 § 182.6778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic). (b) Conditions of use. This...

  18. 21 CFR 182.8778 - Sodium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium phosphate. 182.8778 Section 182.8778 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8778 Sodium phosphate. (a) Product. Sodium phosphate (mono-,...

  19. 21 CFR 582.6778 - Sodium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Sodium phosphate. 582.6778 Section 582.6778 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic). (b) Conditions of use....

  20. 21 CFR 182.8778 - Sodium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium phosphate. 182.8778 Section 182.8778 Food... HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic). (b) Conditions of use. This...

  1. 21 CFR 182.6778 - Sodium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium phosphate. 182.6778 Section 182.6778 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Sequestrants 1 § 182.6778 Sodium phosphate. (a) Product. Sodium phosphate...

  2. 21 CFR 582.1778 - Sodium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Sodium phosphate. 582.1778 Section 582.1778 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic)....

  3. 21 CFR 182.8778 - Sodium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium phosphate. 182.8778 Section 182.8778 Food... HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic). (b) Conditions of use. This...

  4. 21 CFR 582.1778 - Sodium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Sodium phosphate. 582.1778 Section 582.1778 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic)....

  5. 21 CFR 582.6778 - Sodium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Sodium phosphate. 582.6778 Section 582.6778 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic). (b) Conditions of use....

  6. 21 CFR 182.6778 - Sodium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium phosphate. 182.6778 Section 182.6778 Food... HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Sequestrants 1 § 182.6778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic). (b) Conditions of use. This...

  7. 21 CFR 582.1778 - Sodium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium phosphate. 582.1778 Section 582.1778 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic)....

  8. 21 CFR 182.1778 - Sodium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium phosphate. 182.1778 Section 182.1778 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic)....

  9. 21 CFR 182.1778 - Sodium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium phosphate. 182.1778 Section 182.1778 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic)....

  10. 21 CFR 182.8778 - Sodium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium phosphate. 182.8778 Section 182.8778 Food... HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic). (b) Conditions of use. This...

  11. 21 CFR 182.1778 - Sodium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium phosphate. 182.1778 Section 182.1778 Food... GENERALLY RECOGNIZED AS SAFE Multiple Purpose GRAS Food Substances § 182.1778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic). (b) Conditions of use. This substance is...

  12. 21 CFR 182.6778 - Sodium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium phosphate. 182.6778 Section 182.6778 Food... HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Sequestrants 1 § 182.6778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic). (b) Conditions of use. This...

  13. 21 CFR 582.6778 - Sodium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Sodium phosphate. 582.6778 Section 582.6778 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic). (b) Conditions of use....

  14. 21 CFR 582.5778 - Sodium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Sodium phosphate. 582.5778 Section 582.5778 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic)....

  15. 21 CFR 182.1778 - Sodium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium phosphate. 182.1778 Section 182.1778 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic)....

  16. 21 CFR 582.6778 - Sodium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium phosphate. 582.6778 Section 582.6778 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic). (b) Conditions of use....

  17. 21 CFR 182.6778 - Sodium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium phosphate. 182.6778 Section 182.6778 Food... HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Sequestrants 1 § 182.6778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic). (b) Conditions of use. This...

  18. 21 CFR 182.1778 - Sodium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium phosphate. 182.1778 Section 182.1778 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic)....

  19. 21 CFR 582.5778 - Sodium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Sodium phosphate. 582.5778 Section 582.5778 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic)....

  20. 21 CFR 182.8778 - Sodium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium phosphate. 182.8778 Section 182.8778 Food... HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic). (b) Conditions of use. This...

  1. 21 CFR 582.1778 - Sodium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Sodium phosphate. 582.1778 Section 582.1778 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1778 Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic)....

  2. 21 CFR 582.6778 - Sodium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Sodium phosphate. 582.6778 Section 582.6778 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Sodium phosphate. (a) Product. Sodium phosphate (mono-, di-, and tribasic). (b) Conditions of use....

  3. Urea phosphate as granular or fluid fertilizers

    SciTech Connect

    Blouin, G.M.

    1984-01-01

    Studies are being conducted of the production and agronomic characteristics of the phosphoric acid-urea adduct, urea phosphate, and of the various granular and fluid fertilizers that can be produced from it. Flowsheets are given for the production of urea phosphate. Characteristics of unpurified and purified urea phosphate are also given. (DLC)

  4. 21 CFR 182.1217 - Calcium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium phosphate. 182.1217 Section 182.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  5. 21 CFR 182.8217 - Calcium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium phosphate. 182.8217 Section 182.8217 Food... HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic). (b) Conditions of use. This...

  6. 21 CFR 182.1217 - Calcium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium phosphate. 182.1217 Section 182.1217 Food... GENERALLY RECOGNIZED AS SAFE Multiple Purpose GRAS Food Substances § 182.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic). (b) Conditions of use. This substance is...

  7. 21 CFR 582.1217 - Calcium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Calcium phosphate. 582.1217 Section 582.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  8. 21 CFR 582.1217 - Calcium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium phosphate. 582.1217 Section 582.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  9. 21 CFR 182.1217 - Calcium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium phosphate. 182.1217 Section 182.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  10. 21 CFR 582.1217 - Calcium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Calcium phosphate. 582.1217 Section 582.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  11. 21 CFR 182.8217 - Calcium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium phosphate. 182.8217 Section 182.8217 Food... HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic). (b) Conditions of use. This...

  12. 21 CFR 182.8217 - Calcium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium phosphate. 182.8217 Section 182.8217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8217 Calcium phosphate. (a) Product. Calcium phosphate...

  13. 21 CFR 182.8217 - Calcium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium phosphate. 182.8217 Section 182.8217 Food... HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic). (b) Conditions of use. This...

  14. 21 CFR 582.1217 - Calcium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Calcium phosphate. 582.1217 Section 582.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  15. 21 CFR 182.1217 - Calcium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium phosphate. 182.1217 Section 182.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  16. 21 CFR 582.1217 - Calcium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Calcium phosphate. 582.1217 Section 582.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  17. 21 CFR 182.1217 - Calcium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium phosphate. 182.1217 Section 182.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  18. 21 CFR 182.8217 - Calcium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium phosphate. 182.8217 Section 182.8217 Food... HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic). (b) Conditions of use. This...

  19. 21 CFR 182.6290 - Disodium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Disodium phosphate. 182.6290 Section 182.6290 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... phosphate. (a) Product. Disodium phosphate. (b) Conditions of use. This substance is generally recognized...

  20. 21 CFR 582.1141 - Ammonium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ammonium phosphate. 582.1141 Section 582.1141 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1141 Ammonium phosphate. (a) Product. Ammonium phosphate (mono- and dibasic). (b)...

  1. 21 CFR 182.6285 - Dipotassium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Dipotassium phosphate. 182.6285 Section 182.6285 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Dipotassium phosphate. (a) Product. Dipotassium phosphate. (b) Conditions of use. This substance is...

  2. 21 CFR 582.6290 - Disodium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Disodium phosphate. 582.6290 Section 582.6290 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Disodium phosphate. (a) Product. Disodium phosphate. (b) Conditions of use. This substance is...

  3. 40 CFR 721.5995 - Polyalkyl phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polyalkyl phosphate. 721.5995 Section... Substances § 721.5995 Polyalkyl phosphate. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a polyalkyl phosphate (PMN P-95-1772)...

  4. 21 CFR 582.6285 - Dipotassium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Dipotassium phosphate. 582.6285 Section 582.6285 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Dipotassium phosphate. (a) Product. Dipotassium phosphate. (b) Conditions of use. This substance is...

  5. 21 CFR 182.6290 - Disodium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Disodium phosphate. 182.6290 Section 182.6290 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... phosphate. (a) Product. Disodium phosphate. (b) Conditions of use. This substance is generally recognized...

  6. 21 CFR 182.6285 - Dipotassium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Dipotassium phosphate. 182.6285 Section 182.6285 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Dipotassium phosphate. (a) Product. Dipotassium phosphate. (b) Conditions of use. This substance is...

  7. 21 CFR 582.6285 - Dipotassium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Dipotassium phosphate. 582.6285 Section 582.6285 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Dipotassium phosphate. (a) Product. Dipotassium phosphate. (b) Conditions of use. This substance is...

  8. 21 CFR 582.6290 - Disodium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Disodium phosphate. 582.6290 Section 582.6290 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Disodium phosphate. (a) Product. Disodium phosphate. (b) Conditions of use. This substance is...

  9. 21 CFR 582.1141 - Ammonium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Ammonium phosphate. 582.1141 Section 582.1141 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1141 Ammonium phosphate. (a) Product. Ammonium phosphate (mono- and dibasic). (b)...

  10. Impact damage resistance and residual property assessment of (0/+/-45/90)s SCS-6/Timetal 21S

    NASA Technical Reports Server (NTRS)

    Miller, Jennifer L.; Portanova, Marc A.; Johnson, W. Steven

    1995-01-01

    The impact damage resistance and residual mechanical properties of (0/ +/- 45/90)s SCS-6/Timetal 21S composites were evaluated. Both quasi-static indentation and drop-weight impact tests were used to investigate the impact behavior at two nominal energy levels (5.5 and 8.4 J) and determine the onset of internal damage. Through x-ray inspection, the extent of internal damage was characterized non-destructively. The composite strength and constant amplitude fatigue response were evaluated to assess the effects of the sustained damage. Scanning electron microscopy was used to characterize internal damage from impact in comparison to damage that occurs during mechanical loading alone. The effect of stacking sequence was examined by using specimens with the long dimension of the specimen both parallel (longitudinal) and perpendicular (transverse) to the 0 deg fiber direction. Damage in the form of longitudinal and transverse cracking occurred in all longitudinal specimens tested at energies greater than 6.3 J. Similar results occurred in the transverse specimens tested above 5.4 J. Initial load drop, characteristic of the onset of damage, occurred on average at 6.3 J in longitudinal specimens and at 5.0 J in transverse specimens. X-ray analysis showed broken fibers in the impacted region in specimens tested at the higher impact energies. At low impact energies, visible matrix cracking may occur, but broken fibers may not. Matrix cracking was noted along fiber swims and it appeared to depend on the surface quality of composite. At low impact energies, little damage has been incurred by the composite and the residual strength and residual life is not greatly reduced as compared to an undamaged composite. At higher impact energies, more damage occurred and a greater effect of the impact damage was observed.

  11. Thermomechanical Fatigue Damage/Failure Mechanisms in SCS-6/Timetal 21S [0/90](Sub S) Composite

    NASA Technical Reports Server (NTRS)

    Castelli, Michael G.

    1994-01-01

    The thermomechanical fatigue (TMF) deformation, damage, and life behaviors of SCS6/Timetal 21S (0/90)s were investigated under zero-tension conditions. In-phase (IP) and out-of-phase (OP) loadings were investigated with a temperature cycle from 150 to 650 deg C. An advanced TMF test technique was used to quantify mechanically damage progression. The technique incorporated explicit measurements of the macroscopic (1) isothermal static moduli at the temperature extremes of the TMF cycle and (2) coefficient of thermal expansion (CTE) as functions of the TMF cycles. The importance of thermal property degradation and its relevance to accurate post-test data analysis and interpretation is briefly addressed. Extensive fractography and metallography were conducted on specimens from failed and interrupted tests to characterize the extent of damage at the microstructure level. Fatigue life results indicated trends analogous to those established for similar unidirectional(0) reinforced titanium matrix composite systems. High stress IP and mid to low stress OP loading conditions were life-limiting in comparison to maximum temperature isothermal conditions. Dominant damage mechanisms changed with cycle type. Damage resulting from IP TMF conditions produced measurable decreases in static moduli but only minimal changes in the CTE. Metallography on interrupted and failed specimens revealed extensive (0) fiber cracking with sparse matrix damage. No surface initiated matrix cracks were present. Comparable OP TMF conditions initiated environment enhanced surface cracking and matrix cracking initiated at (90) fiber/matrix (F/M) interfaces. Notable static moduli and CTE degradations were measured. Fractography and metallography revealed that the transverse cracks originating from the surface and (90) F/M interfaces tended to converge and coalesce at the (0) fibers.

  12. Characterization of Damage Progression in SCS-6/timetal 21S (0)4 Under Thermomechanical Fatigue Loadings

    NASA Technical Reports Server (NTRS)

    Castelli, Michael G.

    1994-01-01

    A detailed experimental investigation was performed at a single maximum cyclic stress (sigma max) level to physically characterize the progression of thermomechanical fatigue (lW) damage in continuously reinforced (0 deg) SCS-6/Timetal 21S, a titanium matrix composite. In-phase (IP) and out of-phase (OP) loadings were investigated at sigma max = 1000 MPa with a temperature cycle from 150 to 6500 C. Damage progression, in terms of macroscopic property degradation, was experimentally quantified through an advanced TMF test methodology which incorporates explicit measurements of the isothermal static moduli at the TMF temperature extremes and the coefficient of thermal expansion (CTE) as functions of the TMF cycles. Detailed characterization of the physical damage progression at the microstructural level was performed by interrupting multiple TMF tests at various stages of mechanical property degradation and analyzing the microstructure through extensive destructive metallography. Further, the extent of damage was also quantified through residual static strength measurements. Results indicated that damage initiation occurred very early in cyclic life (N less than 0.1Nf) for both the IP and OP TMF loadings. IP TMF damage was found to be dominated by fiber breakage with a physical damage progression in the microstructure which was difficult to quantify. OP TMF loadings produced matrix cracking exclusively associated with surface initiations. Here, damage progression was easily distinguished in terms of both the number of cracks and their relative inward progressions toward the outer fiber rows with increased cycling. The point at which the leading cracks reached the outer fiber rows (when localized fiber/matrix de-bonding and matrix crack bridging occurred) appeared to be reflected in the macroscopic property degradation curves.

  13. Nucleoside phosphorylation by phosphate minerals.

    PubMed

    Costanzo, Giovanna; Saladino, Raffaele; Crestini, Claudia; Ciciriello, Fabiana; Di Mauro, Ernesto

    2007-06-01

    In the presence of formamide, crystal phosphate minerals may act as phosphate donors to nucleosides, yielding both 5'- and, to a lesser extent, 3'-phosphorylated forms. With the mineral Libethenite the formation of 5'-AMP can be as high as 6% of the adenosine input and last for at least 10(3) h. At high concentrations, soluble non-mineral phosphate donors (KH(2)PO(4) or 5'-CMP) afford 2'- and 2':3'-cyclic AMP in addition to 5'-and 3'-AMP. The phosphate minerals analyzed were Herderite Ca[BePO(4)F], Hureaulite Mn(2+)(5)(PO(3)(OH)(2)(PO(4))(2)(H(2)O)(4), Libethenite Cu(2+)(2)(PO(4))(OH), Pyromorphite Pb(5)(PO(4))(3)Cl, Turquoise Cu(2+)Al(6)(PO(4))(4)(OH)(8)(H(2)O)(4), Fluorapatite Ca(5)(PO(4))(3)F, Hydroxylapatite Ca(5)(PO(4))(3)OH, Vivianite Fe(2+)(3)(PO(4))(2)(H(2)O)(8), Cornetite Cu(2+)(3)(PO(4))(OH)(3), Pseudomalachite Cu(2+)(5)(PO(4))(2)(OH)(4), Reichenbachite Cu(2+)(5)(PO(4))(2)(OH)(4), and Ludjibaite Cu(2+)(5)(PO(4))(2)(OH)(4)). Based on their behavior in the formamide-driven nucleoside phosphorylation reaction, these minerals can be characterized as: 1) inactive, 2) low level phosphorylating agents, or 3) active phosphorylating agents. Instances were detected (Libethenite and Hydroxylapatite) in which phosphorylation occurs on the mineral surface, followed by release of the phosphorylated compounds. Libethenite and Cornetite markedly protect the beta-glycosidic bond. Thus, activated nucleic monomers can form in a liquid non-aqueous environment in conditions compatible with the thermodynamics of polymerization, providing a solution to the standard-state Gibbs free energy change (DeltaG degrees ') problem, the major obstacle for polymerizations in the liquid phase in plausible prebiotic scenarios.

  14. Bioavailable dietary phosphate, a mediator of cardiovascular disease, may be decreased with plant-based diets, phosphate binders, niacin, and avoidance of phosphate additives.

    PubMed

    McCarty, Mark F; DiNicolantonio, James J

    2014-01-01

    Increased fasting serum phosphate within the normal physiological range has been linked to increased cardiovascular risk in prospective epidemiology; increased production of fibroblast growth factor 23, and direct vascular effects of phosphate, may mediate this risk. Although dietary phosphate intake does not clearly influence fasting serum phosphate in individuals with normal renal function, increased phosphate intake can provoke a rise in fibroblast growth factor 23, and in diurnal phosphate levels, and hence may adversely influence vascular health. Dietary phosphate absorption can be moderated by emphasizing plant-based dietary choices (which provide phosphate in less bioavailable forms); avoidance of processed foods containing inorganic phosphate food additives; and by ingestion of phosphate-binder drugs, magnesium supplements, or niacin, which precipitate phosphate or suppress its gastrointestinal absorption. The propensity of dietary phosphate to promote vascular calcification may be opposed by optimal intakes of magnesium, vitamin K, and vitamin D; the latter should also counter the tendency of phosphate to elevate parathyroid hormone.

  15. Phosphate: are we squandering a scarce commodity?

    PubMed

    Ferro, Charles J; Ritz, Eberhard; Townend, Jonathan N

    2015-02-01

    Phosphorus is an essential element for life but is a rare element in the universe. On Earth, it occurs mostly in the form of phosphates that are widespread but predominantly at very low concentration. This relative rarity has resulted in a survival advantage, in evolutionary terms, to organisms that conserve phosphate. When phosphate is made available in excess it becomes a cause for disease, perhaps best recognized as a potential cardiovascular and renal risk factor. As a reaction to the emerging public health issue caused by phosphate additives to food items, there have been calls for a public education programme and regulation to bring about a reduction of phosphate additives to food. During the Paleoproterzoic era, an increase in the bioavailability of phosphate is thought to have contributed significantly to the oxygenation of our atmosphere and a dramatic increase in the evolution of new species. Currently, phosphate is used poorly and often wasted with phosphate fertilizers washing this scarce commodity into water bodies causing eutrophication and algal blooms. Ironically, this is leading to the extinction of hundreds of species. The unchecked exploitation of phosphate rock, which is an increasingly rare natural resource, and our dependence on it for agriculture may lead to a strange situation in which phosphate might become a commodity to be fought over whilst at the same time, health and environmental experts are likely to recommend reductions in its use.

  16. A vacuolar phosphate transporter essential for phosphate homeostasis in Arabidopsis

    PubMed Central

    Liu, Jinlong; Yang, Lei; Luan, Mingda; Wang, Yuan; Zhang, Chi; Zhang, Bin; Shi, Jisen; Zhao, Fu-Geng; Lan, Wenzhi; Luan, Sheng

    2015-01-01

    Inorganic phosphate (Pi) is stored in the vacuole, allowing plants to adapt to variable Pi availability in the soil. The transporters that mediate Pi sequestration into vacuole remain unknown, however. Here we report the functional characterization of Vacuolar Phosphate Transporter 1 (VPT1), an SPX domain protein that transports Pi into the vacuole in Arabidopsis. The vpt1 mutant plants were stunted and consistently retained less Pi than wild type plants, especially when grown in medium containing high levels of Pi. In seedlings, VPT1 was expressed primarily in younger tissues under normal conditions, but was strongly induced by high-Pi conditions in older tissues, suggesting that VPT1 functions in Pi storage in young tissues and in detoxification of high Pi in older tissues. As a result, disruption of VPT1 rendered plants hypersensitive to both low-Pi and high-Pi conditions, reducing the adaptability of plants to changing Pi availability. Patch-clamp analysis of isolated vacuoles showed that the Pi influx current was severely reduced in vpt1 compared with wild type plants. When ectopically expressed in Nicotiana benthamiana mesophyll cells, VPT1 mediates vacuolar influx of anions, including Pi, SO42−, NO3−, Cl−, and malate with Pi as that preferred anion. The VPT1-mediated Pi current amplitude was dependent on cytosolic phosphate concentration. Single-channel analysis showed that the open probability of VPT1 was increased with the increase in transtonoplast potential. We conclude that VPT1 is a transporter responsible for vacuolar Pi storage and is essential for Pi adaptation in Arabidopsis. PMID:26554016

  17. D21S418E identifies a cAMP-regulated gene located on chromosome 21q22. 3 that is expressed in placental syncytiotrophoblast and choriocarcinoma cells

    SciTech Connect

    Kido, S.; Sakuragi, N.; Bronner, M.P.; Sayegh, R.; Strauss, J.F. III ); Berger, R.; Patterson, D. )

    1993-07-01

    A partial cDNA (D21S418E) whose nucleotide sequence has no significant homologies with known mammalian DNA sequences was isolated from a human placental library. The cDNA hybridized with a 10-kb transcript present in term placenta. Messages of 10 and 7.5 kb were induced in BeWo and JEG-3 choriocarcinoma cells by treatment with 8-Br-cAMP. The mRNA was not detected in human brain, liver, lung, kidney, pancreas, heart, skeletal muscle, or myometrium. The D21S418E locus was assigned to a 3.5-Mb region of chromosome 21q22.3. 15 refs., 2 figs., 1 tab.

  18. Insight into biological phosphate recovery from sewage.

    PubMed

    Ye, Yuanyao; Ngo, Huu Hao; Guo, Wenshan; Liu, Yiwen; Zhang, Xinbo; Guo, Jianbo; Ni, Bing-Jie; Chang, Soon Woong; Nguyen, Dinh Duc

    2016-10-01

    The world's increasing population means that more food production is required. A more sustainable supply of fertilizers mainly consisting of phosphate is needed. Due to the rising consumption of scarce resources and limited natural supply of phosphate, the recovery of phosphate and their re-use has potentially high market value. Sewage has high potential to recover a large amount of phosphate in a circular economy approach. This paper focuses on utilization of biological process integrated with various subsequent processes to concentrate and recycle phosphate which are derived from liquid and sludge phases. The phosphate accumulation and recovery are discussed in terms of mechanism and governing parameters, recovery efficiency, application at plant-scale and economy. PMID:27434305

  19. Insight into biological phosphate recovery from sewage.

    PubMed

    Ye, Yuanyao; Ngo, Huu Hao; Guo, Wenshan; Liu, Yiwen; Zhang, Xinbo; Guo, Jianbo; Ni, Bing-Jie; Chang, Soon Woong; Nguyen, Dinh Duc

    2016-10-01

    The world's increasing population means that more food production is required. A more sustainable supply of fertilizers mainly consisting of phosphate is needed. Due to the rising consumption of scarce resources and limited natural supply of phosphate, the recovery of phosphate and their re-use has potentially high market value. Sewage has high potential to recover a large amount of phosphate in a circular economy approach. This paper focuses on utilization of biological process integrated with various subsequent processes to concentrate and recycle phosphate which are derived from liquid and sludge phases. The phosphate accumulation and recovery are discussed in terms of mechanism and governing parameters, recovery efficiency, application at plant-scale and economy.

  20. Phosphate-limited culture of Azotobacter vinelandii.

    PubMed Central

    Tsai, J C; Aladegbami, S L; Vela, G R

    1979-01-01

    Batch cultures of Azotobacter vinelandii grown in phosphate-deficient media were compared with control cultures grown in phosphate-sufficient media. Phosphate limitation was assessed by total cell yield and by growth kinetics. Although cell protein, nucleic acids, and early growth rate were unaffected by phosphate deficiency, cell wall structure, oxygen uptake, and cell viability were significantly affected. Also, phosphate-limited cells contained much larger amounts of poly-beta-hydroxybutyric acid but lower adenylate nucleotide energy charge than did control cells. The ratio of adenosine 5'-triphosphate to adenosine 5'-diphosphate was much lower in phosphate-deficient cells. The data indicate a substrate saving choice of three metabolic pathways available to this organism under different growth conditions. Images PMID:457614

  1. Application of Calcium Phosphate Materials in Dentistry

    PubMed Central

    Al-Sanabani, Jabr S.; Al-Sanabani, Fadhel A.

    2013-01-01

    Calcium phosphate materials are similar to bone in composition and in having bioactive and osteoconductive properties. Calcium phosphate materials in different forms, as cements, composites, and coatings, are used in many medical and dental applications. This paper reviews the applications of these materials in dentistry. It presents a brief history, dental applications, and methods for improving their mechanical properties. Notable research is highlighted regarding (1) application of calcium phosphate into various fields in dentistry; (2) improving mechanical properties of calcium phosphate; (3) biomimetic process and functionally graded materials. This paper deals with most common types of the calcium phosphate materials such as hydroxyapatite and tricalcium phosphate which are currently used in dental and medical fields. PMID:23878541

  2. Mineral induced formation of sugar phosphates

    NASA Technical Reports Server (NTRS)

    Pitsch, S.; Eschenmoser, A.; Gedulin, B.; Hui, S.; Arrhenius, G.

    1995-01-01

    Glycolaldehyde phosphate, sorbed from highly dilute, weakly alkaline solution into the interlayer of common expanding sheet structure metal hydroxide minerals, condenses extensively to racemic aldotetrose-2, 4-diphophates, and aldohexose-2, 4, 6-triphosphates. The reaction proceeds mainly through racemic erythrose-2, 4-phosphate, and terminates with a large fraction of racemic altrose-2, 4, 6-phosphate. In the absence of an inductive mineral phase, no detectable homogeneous reaction takes place in the concentration- and pH range used. The reactant glycolaldehyde phosphate is practically completely sorbed within an hour from solutions with concentrations as low as 50 micron; the half-time for conversion to hexose phosphates is of the order of two days at room temperature and pH 9.5. Total production of sugar phosphates in the mineral interlayer is largely independent of the glycolaldehyde phosphate concentration in the external solution, but is determined by the total amount of GAP offered for sorption up to the capacity of the mineral. In the presence of equimolar amounts of rac-glyceraldehyde-2-phosphate, but under otherwise similar conditions, aldopentose-2, 4, -diphosphates also form, but only as a small fraction of the hexose-2, 4, 6-phosphates.

  3. Preparation of porous lanthanum phosphate with templates

    SciTech Connect

    Onoda, Hiroaki; Ishima, Yuya; Takenaka, Atsushi; Tanaka, Isao

    2009-08-05

    Malonic acid, propionic acid, glycine, n-butylamine, and urea were added to the preparation of lanthanum phosphate from lanthanum nitrate and phosphoric acid solutions. All additives were taken into lanthanum phosphate particles. The additives that have a basic site were easy to contain in precipitates. The addition of templates improved the specific surface area of lanthanum phosphate. The amount of pore, with radius smaller than 4 nm, increased with the addition of templates. The remained additives had influence on the acidic properties of lanthanum phosphate.

  4. Next generation calcium phosphate-based biomaterials

    PubMed Central

    LC, Chow

    2009-01-01

    It has been close to a century since calcium phosphate materials were first used as bone graft substitutes. Numerous studies conducted in the last two decades have produced a wealth of information on the chemistry, in vitro properties, and biological characteristics of granular calcium phosphates and calcium phosphate cement biomaterials. An in depth analysis of several key areas of calcium phosphate cement properties is presented with the aim of developing strategies that could lead to break-through improvements in the functional efficacies of these materials. PMID:19280963

  5. The SLC37 Family of Sugar-Phosphate/Phosphate Exchangers

    PubMed Central

    Chou, Janice Y.; Mansfield, Brian C.

    2014-01-01

    The SLC37 family members are endoplasmic reticulum (ER)-associated sugar-phosphate/phosphate (Pi) exchangers. Three of the four members, SLC37A1, SLC37A2, and SLC37A4, function as Pi-linked glucose-6-phosphate (G6P) antiporters catalyzing G6P:Pi and Pi:Pi exchanges. The activity of SLC37A3 is unknown. SLC37A4, better known as the G6P transporter (G6PT), has been extensively characterized, functionally and structurally, and is the best characterized family member. G6PT contains 10 transmembrane helices with both N and C termini facing the cytoplasm. The primary in vivo function of the G6PT protein is to translocate G6P from the cytoplasm into the ER lumen where it couples with either the liver/kidney/intestine-restricted glucose-6-phosphatase-α (G6Pase-α or G6PC) or the ubiquitously expressed G6Pase-β (or G6PC3) to hydrolyze G6P to glucose and Pi. The G6PT/G6Pase-α complex maintains interprandial glucose homeostasis, and the G6PT/G6Pase-β complex maintains neutro-phil energy homeostasis and functionality. G6PT is highly selective for G6P and is competitively inhibited by cholorogenic acid and its derivatives. Neither SLC37A1 nor SLC37A2 can couple functionally with G6Pase-α or G6Pase-β, and the antiporter activities of SLC37A1 or SLC37A2 are not inhibited by cholorogenic acid. Deficiencies in G6PT cause glycogen storage disease type Ib (GSD-Ib), a metabolic and immune disorder. To date, 91 separate SLC37A4 mutations, including 39 missense mutations, have been identified in GSD-Ib patients. Characterization of missense mutations has yielded valuable information on functionally important residues in the G6PT protein. The biological roles of the other SLC37 proteins remain to be determined and deficiencies have not yet been correlated to diseases. PMID:24745989

  6. Con: Phosphate binders in chronic kidney disease.

    PubMed

    Kestenbaum, Bryan

    2016-02-01

    Phosphate binders are prescribed to chronic kidney disease (CKD) patients based on associations of serum phosphate concentrations with mortality and calcification, experimental evidence for direct calcifying effects of phosphate on vascular smooth muscle tissue and the central importance of phosphate retention in CKD-mineral and bone disorder (CKD-MBD). Current knowledge regarding phosphate metabolism in CKD provides important insight into disease mechanisms and supports future clinical trials of phosphate binders in CKD patients to determine the impact of these medications on clinically relevant outcomes. The risks and benefits of phosphate binders cannot be inferred from association studies of serum phosphate concentrations, which are inconsistent and subject to confounding, animal-experimental data, which are based on conditions that differ from human disease, or physiological arguments, which are limited to known regulatory factors. Many interventions that targeted biochemical pathways suggested by association studies and suspected biological importance have yielded null or harmful results. Clinical trials of phosphate binders are of high clinical and scientific importance to nephrology. Demonstration of reduced rates of clinical disease in such trials could lead to important health benefits for CKD patients, whereas negative results would refocus efforts to understand and treat CKD-MBD. Clinical trials that employ highly practical or 'pragmatic' designs represent an optimal approach for determining the safety and effectiveness of phosphate binders in real-world settings. Absent clinical trial data, observational studies of phosphate binders in large CKD populations could provide important information regarding the benefits, risks and/or unintended side effects of these medications. PMID:26681747

  7. The measurement of xylulose 5-phosphate, ribulose 5-phosphate, and combined sedoheptulose 7-phosphate and ribose 5-phosphate in liver tissue.

    PubMed

    Casazza, J P; Veech, R L

    1986-12-01

    A modification of the method of Kauffman et al. (F. C. Kauffman, J. G. Brown, J. V. Passonneau, and O. H. Lowry (1969) J. Biol. Chem. 244, 3647-3653) for the spectrophotometric determination of xylulose 5-phosphate, ribulose 5-phosphate, and combined ribose 5-phosphate and sedoheptulose 7-phosphate in tissue extract is presented. Using commercially available enzymes all three assays come to a clear endpoint with the assays described. Values for these metabolites in liver in three dietary states are reported; 48 h starved, ad libitum feeding of standard NIH rat ration, and meal feeding of a fat-free diet. Xylulose 5-phosphate values were 3.8 +/- 0.3, 8.6 +/- 0.3, and 66.3 +/- 8.3 nmol/g. Ribulose 5-phosphate values were 3.4 +/- 0.3, 5.8 +/- 0.2, and 37.1 +/- 5.3 nmol/g. Combined ribose 5-phosphate and sedoheptulose 7-phosphate were 29.3 +/- 0.3, 38.2 +/- 1.2, and 108.2 +/- 14.5 nmol/g. The ratio of measured tissue content of [xylulose 5-phosphate]/[ribulose 5-phosphate] was found to be 1.12 +/- 0.07 in starved animals, 1.48 +/- 0.04 in ad libitum fed animals and 1.78 +/- 0.03 in low-fat meal fed animals. These data are in good agreement with the range of equilibrium constants reported for this reaction, suggesting that the ribulose 5-phosphate 3-epimerase reaction (EC 5.1.3.1) is a near equilibrium reaction despite a more than 10-fold change in the tissue content of these metabolites.

  8. Removal of phosphate from solution by adsorption and precipitation of calcium phosphate onto monohydrocalcite.

    PubMed

    Yagi, Shintaro; Fukushi, Keisuke

    2012-10-15

    The sorption behavior and mechanism of phosphate on monohydrocalcite (CaCO(3)·H(2)O: MHC) were examined using batch sorption experiments as a function of phosphate concentrations, ionic strengths, temperatures, and reaction times. The mode of PO(4) sorption is divisible into three processes depending on the phosphate loading. At low phosphate concentrations, phosphate is removed by coprecipitation of phosphate during the transformation of MHC to calcite. The sorption mode at the low-to-moderate phosphate concentrations is most likely an adsorption process because the sorption isotherm at the conditions can be fitted reasonably with the Langmuir equation. The rapid sorption kinetics at the conditions is also consistent with the adsorption reaction. The adsorption of phosphate on MHC depends strongly on ionic strength, but slightly on temperature. The maximum adsorption capacities of MHC obtained from the regression of the experimental data to the Langmuir equation are higher than those reported for stable calcium carbonate (calcite or aragonite) in any conditions. At high phosphate concentrations, the amount of sorption deviates from the Langmuir isotherm, which can fit the low-to-moderate phosphate concentrations. Speciation-saturation analyses of the reacted solutions at the conditions indicated that the solution compositions which deviate from the Langmuir equation are supersaturated with respect to a certain calcium phosphate. The obtained calcium phosphate is most likely amorphous calcium phosphate (Ca(3)(PO(4))(2)·xH(2)O). The formation of the calcium phosphate depends strongly on ionic strength, temperature, and reaction times. The solubility of MHC is higher than calcite and aragonite because of its metastability. Therefore, the higher solubility of MHC facilitates the formation of the calcium phosphates more than with calcite and aragonite.

  9. Mineral resource of the month: phosphate rock

    USGS Publications Warehouse

    Jasinski, Stephen M.

    2007-01-01

    Phosphate rock minerals provide the only significant global resources of phosphorus, which is an essential element for plant and animal nutrition. Phosphate rock is used primarily as a principal component of nitrogen-phosphorus-potassium fertilizers, but also to produce elemental phosphorus and animal feed.

  10. How inositol pyrophosphates control cellular phosphate homeostasis?

    PubMed

    Saiardi, Adolfo

    2012-05-01

    Phosphorus in his phosphate PO(4)(3-) configuration is an essential constituent of all life forms. Phosphate diesters are at the core of nucleic acid structure, while phosphate monoester transmits information under the control of protein kinases and phosphatases. Due to these fundamental roles in biology it is not a surprise that phosphate cellular homeostasis is under tight control. Inositol pyrophosphates are organic molecules with the highest proportion of phosphate groups, and they are capable of regulating many biological processes, possibly by controlling energetic metabolism and adenosine triphosphate (ATP) production. Furthermore, inositol pyrophosphates influence inorganic polyphosphates (polyP) synthesis. The polymer polyP is solely constituted by phosphate groups and beside other known functions, it also plays a role in buffering cellular free phosphate [Pi] levels, an event that is ultimately necessary to generate ATP and inositol pyrophosphate. Although it is not yet clear how inositol pyrophosphates regulate cellular metabolism, understanding how inositol pyrophosphates influence phosphates homeostasis will help to clarify this important link. In this review I will describe the recent literature on this topic, with in the hope of inspiring further research in this fascinating area of biology.

  11. Metallic function of lithium phosphate glass electrodes

    SciTech Connect

    Kochetova, T.I.; Bobrov, V.S.

    1995-05-20

    Specificity of metallic functions of lithium phosphate glasses toward univalent cations over a wide concentration range and their correlation with cation size have been studied. In the present work, the authors extended the spectrum of phosphate glass compositions: a study has been made how additions of gallium, titanium, and vanadium oxides influence electrode properties.

  12. Phosphate rock resources of the United States

    USGS Publications Warehouse

    Cathcart, James Bachelder; Sheldon, Richard Porter; Gulbrandsen, Robert A.

    1984-01-01

    In 1980, the United States produced about 54 million tons of phosphate rock, or about 40 percent of the world's production, of which a substantial amount was exported, both as phosphate rock and as chemical fertilizer. During the last decade, predictions have been made that easily ruinable, low-cost reserves of phosphate rock would be exhausted, and that by the end of this century, instead of being a major exporter of phosphate rock, the United States might become a net importer. Most analysts today, however, think that exports will indeed decline in the next one or two decades, but that resources of phosphate are sufficient to supply domestic needs for a long time into the future. What will happen in the future depends on the actual availability of low-cost phosphate rock reserves in the United States and in the world. A realistic understanding of future phosphate rock reserves is dependent on an accurate assessment, now, of national phosphate rock resources. Many different estimates of resources exist; none of them alike. The detailed analysis of past resource estimates presented in this report indicates that the estimates differ more in what is being estimated than in how much is thought to exist. The phosphate rock resource classification used herein is based on the two fundamental aspects of a mineral resource(l) the degree of certainty of existence and (2) the feasibility of economic recovery. The comparison of past estimates (including all available company data), combined with the writers' personal knowledge, indicates that 17 billion metric tons of identified, recoverable phosphate rock exist in the United States, of which about 7 billion metric tons are thought to be economic or marginally economic. The remaining 10 billion metric tons, mostly in the Northwestern phosphate district of Idaho, are considered to be subeconomic, ruinable when some increase in the price of phosphate occurs. More than 16 billion metric tons probably exist in the southeastern

  13. Effects of Nickel on Calcium Phosphate Formation

    NASA Astrophysics Data System (ADS)

    Guerra-López, J.; González, R.; Gómez, A.; Pomés, R.; Punte, G.; Della Védova, C. O.

    2000-05-01

    We have investigated the effect of nickel on calcium phosphate formation from aqueous solutions. The calcium phosphates prepared under different reaction conditions (pH, temperature, and nickel concentration) were characterized by X-ray diffraction, FTIR spectroscopy, and chemical analysis. The apatite compounds were also studied thermogravimetrically. From the combined results of the techniques employed we have determined that nickel favors the formation of brushite and amorphous calcium phosphate. We have found, as well, that the presence of nickel in the solution inhibits calcium hydroxyapatite (CaHAP) and octacalcium phosphate formation. However in the synthesis performed at basic pH and 95°C the apatitic phase (HAP) could be obtained. The present results suggest that the presence of nickel may modify the precipitation of oral calcium phosphate.

  14. Phosphate transport and arsenate resistance in the cyanobacterium Anabaena variabilis

    SciTech Connect

    Thiel, T.

    1988-03-01

    Cells of the cyanobacterium Anabaena variabilis starved for phosphate for 3 days took up phosphate at about 100 times the rate of unstarved cells.Kinetic data suggested that a new transport system had been induced by starvation for phosphate. The inducible phosphate transport system was quickly repressed by addition of P/sub i/. Phosphate-starved cells were more sensitive to the toxic effects of arsenate than were unstarved cells, but phosphate could alleviate some of the toxicity. Arsenate was a noncompetitive inhibitor of phosphate transport; however, the apparent K/sub i/ values were high, particularly for phosphate-replete cells. Preincubation of phosphate-starved cells with arsenate caused subsequent inhibition of phosphate transport, suggesting that intracellular arsenate inhibited phosphate transport. This effect was not seen in phosphate-replete cells.

  15. Nanoporous sorbent material as an oral phosphate binder and for aqueous phosphate, chromate, and arsenate removal

    PubMed Central

    Sangvanich, Thanapon; Ngamcherdtrakul, Worapol; Lee, Richard; Morry, Jingga; Castro, David; Fryxell, Glen E.; Yantasee, Wassana

    2014-01-01

    Phosphate removal is both biologically and environmentally important. Biologically, hyperphosphatemia is a critical condition in end-stage chronic kidney disease patients. Patients with hyperphosphatemia are treated long-term with oral phosphate binders to prevent phosphate absorption to the body by capturing phosphate in the gastrointestinal (GI) tract followed by fecal excretion. Environmentally, phosphate levels in natural water resources must be regulated according to limits set forth by the US Environmental Protection Agency. By utilizing nanotechnology and ligand design, we developed a new material to overcome limitations of traditional sorbent materials such as low phosphate binding capacity, slow binding kinetics, and negative interference by other anions. A phosphate binder based on iron-ethylenediamine on nanoporous silica (Fe-EDA-SAMMS) has been optimized for substrates and Fe(III) deposition methods. The Fe-EDA-SAMMS material had a 4-fold increase in phosphate binding capacity and a broader operating pH window compared to other reports. The material had a faster phosphate binding rate and was significantly less affected by other anions than Sevelamer HCl, the gold standard oral phosphate binder, and AG® 1-X8, a commercially available anion exchanger. It had less cytotoxicity to Caco-2 cells than lanthanum carbonate, another prescribed oral phosphate binder. The Fe-EDA-SAMMS also had high capacity for arsenate and chromate, two of the most toxic anions in natural water. PMID:25554735

  16. Phosphate Biomineralization of Cambrian Microorganisms

    NASA Technical Reports Server (NTRS)

    McKay, David S.; Rozanov, Alexei Yu.; Hoover, Richard B.; Westall, Frances

    1998-01-01

    As part of a long term study of biological markers (biomarkers), we are documenting a variety of features which reflect the previous presence of living organisms. As we study meteorites and samples returned from Mars, our main clue to recognizing possible microbial material may be the presence of biomarkers rather than the organisms themselves. One class of biomarkers consists of biominerals which have either been precipitated directly by microorganisms, or whose precipitation has been influenced by the organisms. Such microbe-mediated mineral formation may include important clues to the size, shape, and environment of the microorganisms. The process of fossilization or mineralization can cause major changes in morphologies and textures of the original organisms. The study of fossilized terrestrial organisms can help provide insight into the interpretation of mineral biomarkers. This paper describes the results of investigations of microfossils in Cambrian phosphate-rich rocks (phosphorites) that were found in Khubsugul, Northern Mongolia.

  17. Hydrolysis of dicalcium phosphate dihydrate to hydroxyapatite.

    PubMed

    Fulmer, M T; Brown, P W

    1998-04-01

    Dicalcium phosphate dihydrate (DCPD) was hydrolysed in water and in 1 M Na2HPO4 solution at temperatures from 25-60 degrees C. Hydrolysis was incomplete in water. At 25 degrees C, DCPD partially hydrolysed to hydroxyapatite (HAp). Formation of HAp is indicative of incongruent DCPD dissolution. At the higher temperatures, hydrolysis to HAp was more extensive and was accompanied by the formation of anhydrous dicalcium phosphate (DCP). Both of these processes are endothermic. When hydrolysis was carried out in 1 M Na2HPO4 solution, heat absorption was greater at any given temperature than for hydrolysis in water. Complete hydrolysis to HAp occurred in this solution. The hydrolysis of DCPD to HAp in sodium phosphate solution was also endothermic. The complete conversion of DCPD to HAp in sodium phosphate solution would not be expected if the only effect of this solution was to cause DCPD dissolution to become congruent. Because of the buffering capacity of a dibasic sodium phosphate solution, DCPD hydrolysed completely to HAp. Complete conversion to HAp was accompanied by the conversion of dibasic sodium phosphate to monobasic sodium phosphate. The formation of DCP was not observed indicating that the sodium phosphate solution precluded the DCPD-to-DCP dehydration reaction. In addition to affecting the extent of hydrolysis, reaction in the sodium phosphate solution also caused a morphological change in the HAp which formed. HAp formed by hydrolysis in water was needle-like to globular while that formed in the sodium phosphate solution exhibited a florette-like morphology.

  18. Salicylanilide diethyl phosphates as cholinesterases inhibitors.

    PubMed

    Krátký, Martin; Štěpánková, Šárka; Vorčáková, Katarína; Vinšová, Jarmila

    2015-02-01

    Based on the presence of dialkyl phosphate moiety, we evaluated twenty-seven salicylanilide diethyl phosphates (diethyl [2-(phenylcarbamoyl)phenyl] phosphates) for the inhibition of acetylcholinesterase (AChE) from electric eel (Electrophorus electricus L.) and butyrylcholinesterase (BChE) from equine serum. Ellman's spectrophotometric method was used. The inhibitory activity (expressed as IC50 values) was compared with that of the established drugs galantamine and rivastigmine. Salicylanilide diethyl phosphates showed significant activity against both cholinesterases with IC50 values from 0.903 to 86.3 μM. IC50s for BChE were comparatively lower than those obtained for AChE. All of the investigated compounds showed higher inhibition of AChE than rivastigmine, and six of them inhibited BChE more effectively than both rivastigmine and galantamine. In general, derivatives of 4-chlorosalicylic acid showed enhanced activity when compared to derivatives of 5-halogenated salicylic acids, especially against BChE. The most effective inhibitor of AChE was O-{5-chloro-2-[(3-bromophenyl)carbamoyl]phenyl} O,O-diethyl phosphate with IC50 of 35.4 μM, which is also one of the most potent inhibitors of BChE. O-{5-Chloro-2-[(3,4-dichlorophenyl)carbamoyl]phenyl} O,O-diethyl phosphate exhibited in vitro the strongest inhibition of BChE (0.90 μM). Salicylanilide diethyl phosphates act as pseudo-irreversible cholinesterases inhibitors. PMID:25462625

  19. Are Polyphosphates or Phosphate Esters Prebiotic Reagents?

    NASA Technical Reports Server (NTRS)

    Keefe, Anthony D.; Miller, Stanley L.

    1995-01-01

    It is widely held that there was a phosphate compound in prebiotic chemistry that played the role of adenosine triphosphate and that the first living organisms had ribose-phosphate in the backbone of their genetic material. However, there are no known efficient prebiotic synthesis of high-energy phosphates or phosphate esters. We review the occurrence of phosphates in nature, the efficiency of the volcanic synthesis of P4O10, the efficiency of polyphosphate synthesis by heating phosphate minerals under geological conditions, and the use of high-energy organic compounds such as cyanamide or hydrogen cyanide. These are shown to be inefficient processes especially when the hydrolysis of the polyphosphates is taken into account. For example, if a whole atmosphere of methane or carbon monoxide were converted to cyanide which somehow synthesized polyphosphates quantitatively, the polyphosphate concentration in the ocean would still have been insignificant. We also attempted to find more efficient high-energy polymerizing agents by spark discharge syntheses, but without success. There may still be undiscovered robust prebiotic syntheses of polyphosphates, or mechanisms for concentrating them, but we conclude that phosphate esters may not have been constituents of the first genetic material. Phosphoanhydrides are also unlikely as prebiotic energy sources.

  20. Ribose-5-phosphate biosynthesis in Methanocaldococcus jannaschii occurs in the absence of a pentose-phosphate pathway.

    PubMed

    Grochowski, Laura L; Xu, Huimin; White, Robert H

    2005-11-01

    Recent work has raised a question as to the involvement of erythrose-4-phosphate, a product of the pentose phosphate pathway, in the metabolism of the methanogenic archaea (R. H. White, Biochemistry 43:7618-7627, 2004). To address the possible absence of erythrose-4-phosphate in Methanocaldococcus jannaschii, we have assayed cell extracts of this methanogen for the presence of this and other intermediates in the pentose phosphate pathway and have determined and compared the labeling patterns of sugar phosphates derived metabolically from [6,6-2H2]- and [U-13C]-labeled glucose-6-phosphate incubated with cell extracts. The results of this work have established the absence of pentose phosphate pathway intermediates erythrose-4-phosphate, xylose-5-phosphate, and sedoheptulose-7-phosphate in these cells and the presence of D-arabino-3-hexulose-6-phosphate, an intermediate in the ribulose monophosphate pathway. The labeling of the D-ara-bino-3-hexulose-6-phosphate, as well as the other sugar-Ps, indicates that this hexose-6-phosphate was the precursor to ribulose-5-phosphate that in turn was converted into ribose-5-phosphate by ribose-5-phosphate isomerase. Additional work has demonstrated that ribulose-5-phosphate is derived by the loss of formaldehyde from D-arabino-3-hexulose-6-phosphate, catalyzed by the protein product of the MJ1447 gene.

  1. Aquatic Toxicity Assessment of Phosphate Compounds

    PubMed Central

    Kim, Eunju; Yoo, Sunkyoung; Ro, Hee-Young; Han, Hye-Jin; Baek, Yong-Wook; Eom, Ig-Chun; Kim, Pilje; Choi, Kyunghee

    2013-01-01

    Objectives Tricalcium phosphate and calcium hydrogenorthophosphate are high production volume chemicals, mainly used as foodstuff additives, pharmaceuticals, lubricants, synthetic resin, and disinfectants. Phosphate has the potential to cause increased algal growth leading to eutrophication in the aquatic environment. However, there is no adequate information available on risk assessment or acute and chronic toxicity. The aim of this research is to evaluate the toxic potential of phosphate compounds in the aquatic environment. Methods An aquatic toxicity test of phosphate was conducted, and its physico-chemical properties were obtained from a database recommended in the Organization for Economic Cooperation and Development (OECD) guidance manual. An ecotoxicity test using fish, Daphnia, and algae was conducted by the good laboratory practice facility according to the OECD TG guidelines for testing of chemicals, to secure reliable data. Results The results of the ecotoxicity tests of tricalcium phosphate and calcium hydrogenorthophosphate are as follows: In an acute toxicity test with Oryzias latipes, 96 hr 50% lethal concentration (LC50) was >100 (measured:>2.14) mg/L and >100 (measured: >13.5) mg/L, respectively. In the Daphnia test, 48 hr 50% effective concentration (EC50) was >100 (measured: >5.35) mg/L and >100 (measured: >2.9) mg/L, respectively. In a growth inhibition test with Pseudokirchneriella subcapitata, 72 hr EC50 was >100 (measured: >1.56) mg/L and >100 (measured: >4.4) mg/L, respectively. Conclusions Based on the results of the ecotoxicity test of phosphate using fish, Daphnia, and algae, L(E)C50 was above 100 mg/L (nominal), indicating no toxicity. In general, the total phosphorus concentration including phosphate in rivers and lakes reaches levels of several ppm, suggesting that phosphate has no toxic effects. However, excessive inflow of phosphate into aquatic ecosystems has the potential to cause eutrophication due to algal growth. PMID:23440935

  2. Phosphate-bonded calcium aluminate cements

    DOEpatents

    Sugama, Toshifumi

    1993-01-01

    A method is described for making a rapid-setting phosphate-bonded cementitious material. A powdered aluminous cement is mixed with an aqueous solution of ammonium phosphate. The mixture is allowed to set to form an amorphous cementitious material which also may be hydrothermally treated at a temperature of from about 120.degree. C. to about 300.degree. C. to form a crystal-containing phosphate-bonded material. Also described are the cementitious products of this method and the cement composition which includes aluminous cement and ammonium polyphosphate.

  3. Phosphate-bonded calcium aluminate cements

    DOEpatents

    Sugama, T.

    1993-09-21

    A method is described for making a rapid-setting phosphate-bonded cementitious material. A powdered aluminous cement is mixed with an aqueous solution of ammonium phosphate. The mixture is allowed to set to form an amorphous cementitious material which also may be hydrothermally treated at a temperature of from about 120 C to about 300 C to form a crystal-containing phosphate-bonded material. Also described are the cementitious products of this method and the cement composition which includes aluminous cement and ammonium polyphosphate. 10 figures.

  4. BISMUTH PHOSPHATE CARRIER PROCESS FOR Pu RECOVERY

    DOEpatents

    Finzel, T.G.

    1959-02-01

    An improvement in the bismuth phosphate carrier precipitation process for recovering plutonium is described. It has been found that a more granular and more easily filterable carrier precipitiite is formed if the addition of the bismuth and phosphate ions is effected by first adding 9/10 of the bismuth ions necessary, then slowly adding all of the source of the phosphate ions to be incorporated in the precipitate, while digesting at 75 C and afterwards incorporating the remainder of the total bismuth ions necessary

  5. Non-oxidative synthesis of pentose 5-phosphate from hexose 6-phosphate and triose phosphate by the L-type pentose pathway.

    PubMed

    Williams, J F; Blackmore, P F

    1983-01-01

    1. Ribose 5-phosphate was non-oxidatively synthesized from glucose 6-phosphate and triose phosphate by an enzyme extract prepared from rat liver (RLEP). Analysis of the intermediates by GLC, ion-exchange chromatography and specific enzymatic analysis, revealed the presence of the following intermediates of the L-type pentose pathway: altro-heptulose 1,7-bisphosphate, arabinose 5-phosphate and D-glycero D-ido octulose 8-phosphate. 2. With either [1-14C] or [2-14C]glucose 6-phosphate as diagnostic substrates, the distribution of 14C in ribose 5-phosphate was determined. At early time intervals (0.5-8 hr), [1-14C]glucose 6-phosphate introduced 14C into C-1, C-3 and C-5 of ribose 5-phosphate, at 17 hr 14C was confined to C-1. With [2-14C]glucose 6-phosphate as substrate, 14C was confined to C-2, C-3 and C-5 of ribose 5-phosphate during early times (0.5-8 hr), while at 17 hr 14C was located in C-2. 3. The transketolase exchange reaction, [14C]ribose 5-phosphate + altro-heptulose 7-phosphate in equilibrium ribose 5-phosphate + [14C]altro-heptulose 7-phosphate, was demonstrated for the first time using purified transketolase, its activity was measured and it is proposed to play a major role in the relocation of 14C into C-3 and C-5 or ribose 5-phosphate during the prediction labelling experiments. 4. The coupled transketolase-transaldolase reactions, 2 fructose 6-phosphate in equilibrium altro-heptulose 7-phosphate + xylulose 5-phosphate and 2 altro-heptulose 7-phosphate in equilibrium fructose 6-phosphate + D-glycero D-altro octulose 8-phosphate were demonstrated with purified enzymes, but are concluded to play a minor role in the non-oxidative synthesis of pentose 5-phosphate and octulose phosphate by (RLEP). 5. The formation of gem diol and dimers of erythrose 4-phosphate is proposed to account in part for the failure to detect monomeric erythrose 4-phosphate in the carbon balance studies. 6. The equilibrium value for the pentose pathway acting by the reverse mode in

  6. [Adsorption of Phosphate by Lanthanum Hydroxide/Natural Zeolite Composites from Low Concentration Phosphate Solution].

    PubMed

    Lin, Jian-wei; Wang, Hong; Zhan, Yan-hui; Chen, Dong-mei

    2016-01-15

    A series of composites of lanthanum hydroxide/natural zeolite ( La( OH) 3/NZ composites) were prepared by co-precipitation method, and these composites were used as adsorbents to remove phosphate from aqueous solution. The phosphate adsorption capacities of different composites prepared with different precipitated pH values were compared in batch mode. The adsorption characteristics of phosphate from aqueous solution on the La(OH)3/NZ composite prepared with the precipitated pH value of 11 was investigated using batch experiments. The results showed that the La(OH)3/NZ composite prepared with the precipitated pH values of 5-7 and 13 had a low adsorption capacity for phosphate in aqueous solution, while the La( OH) 3/NZ composites prepared with the precipitated pH values of 9-12 exhibited much higher phosphate adsorption capacity. The phosphate adsorption capacity of the La (OH)3/NZ composite increased with the increase of the precipitated pH value from 9 to 11, but remained basically unchanged with the increase of the precipitated pH value from 11 to 12. The equilibrium adsorption data of phosphate from aqueous solution on the La ( OH ) 3/NZ composite prepared with the precipitated pH value of 11 could be described by the Langmuir isotherm model with the predicted maximum phosphate adsorption of 44 mg x g(-1) (phosphate solution pH 7 and 30 degrees C). The kinetic data of phosphate adsorption from low concentration phosphate solution on the La(OH)3/NZ composite prepared with the precipitated pH value of 11 well followed a pseudo-second-order model. The presence of Cl- and SO4(2-) in low concentration phosphate solution had no negative effect on phosphate adsorption onto the La(OH)3/NZ composite prepared with the precipitated pH value of 11, while the presence of HCO3- slightly inhibited the adsorption of phosphate. Coexisting humic acid had a negative effect on the adsorption of phosphate at low concentration on the La(OH)3/NZ composite prepared with the

  7. [Adsorption of Phosphate by Lanthanum Hydroxide/Natural Zeolite Composites from Low Concentration Phosphate Solution].

    PubMed

    Lin, Jian-wei; Wang, Hong; Zhan, Yan-hui; Chen, Dong-mei

    2016-01-15

    A series of composites of lanthanum hydroxide/natural zeolite ( La( OH) 3/NZ composites) were prepared by co-precipitation method, and these composites were used as adsorbents to remove phosphate from aqueous solution. The phosphate adsorption capacities of different composites prepared with different precipitated pH values were compared in batch mode. The adsorption characteristics of phosphate from aqueous solution on the La(OH)3/NZ composite prepared with the precipitated pH value of 11 was investigated using batch experiments. The results showed that the La(OH)3/NZ composite prepared with the precipitated pH values of 5-7 and 13 had a low adsorption capacity for phosphate in aqueous solution, while the La( OH) 3/NZ composites prepared with the precipitated pH values of 9-12 exhibited much higher phosphate adsorption capacity. The phosphate adsorption capacity of the La (OH)3/NZ composite increased with the increase of the precipitated pH value from 9 to 11, but remained basically unchanged with the increase of the precipitated pH value from 11 to 12. The equilibrium adsorption data of phosphate from aqueous solution on the La ( OH ) 3/NZ composite prepared with the precipitated pH value of 11 could be described by the Langmuir isotherm model with the predicted maximum phosphate adsorption of 44 mg x g(-1) (phosphate solution pH 7 and 30 degrees C). The kinetic data of phosphate adsorption from low concentration phosphate solution on the La(OH)3/NZ composite prepared with the precipitated pH value of 11 well followed a pseudo-second-order model. The presence of Cl- and SO4(2-) in low concentration phosphate solution had no negative effect on phosphate adsorption onto the La(OH)3/NZ composite prepared with the precipitated pH value of 11, while the presence of HCO3- slightly inhibited the adsorption of phosphate. Coexisting humic acid had a negative effect on the adsorption of phosphate at low concentration on the La(OH)3/NZ composite prepared with the

  8. Finite element modeling as a tool for predicting the fracture behavior of robocast scaffolds.

    PubMed

    Miranda, Pedro; Pajares, Antonia; Guiberteau, Fernando

    2008-11-01

    The use of finite element modeling to calculate the stress fields in complex scaffold structures and thus predict their mechanical behavior during service (e.g., as load-bearing bone implants) is evaluated. The method is applied to identifying the fracture modes and estimating the strength of robocast hydroxyapatite and beta-tricalcium phosphate scaffolds, consisting of a three-dimensional lattice of interpenetrating rods. The calculations are performed for three testing configurations: compression, tension and shear. Different testing orientations relative to the calcium phosphate rods are considered for each configuration. The predictions for the compressive configurations are compared to experimental data from uniaxial compression tests.

  9. The oxygen isotopic composition of phosphate in Elkhorn Slough, California: A tracer for phosphate sources

    NASA Astrophysics Data System (ADS)

    McLaughlin, Karen; Cade-Menun, Barbara J.; Paytan, Adina

    2006-11-01

    Elkhorn Slough, a small seasonal estuary in central California, has been subjected to increased nutrient loading from agricultural and other non-point sources. However, because nutrients do not behave conservatively, tracing nutrient sources and cycling in ecosystems like Elkhorn Slough has been difficult to assess. This is particularly true of phosphorus (P), which has only one stable isotope and cannot be used as an isotopic tracer. However, isotopic fractionation of oxygen in phosphate at surface water temperatures only occurs as a result of enzyme-mediated, biochemical reactions. Thus, if phosphate demand is low relative to input and is not heavily cycled within the ecosystem, the δ18O of phosphate will reflect the isotopic composition of phosphate sources to the system. We utilized the δ18O of dissolved inorganic phosphate (DIP) within the main channel of the slough and nearby Moss Landing Harbor and the δ18O of reactive phosphate from sediment and soil samples collected within the watershed to understand phosphate sources and cycling within Elkhorn Slough. Trends in the δ18O of DIP were seasonally consistent with high values near the mouth reflecting oceanic phosphate (19.1‰-20.3‰), dropping to a minimum value near Hummingbird Island in the central slough (point source, 14.1‰-14.4‰), and increasing again near the head of the slough, reflecting fertilizer input (18.9‰-19.3‰). Reactive phosphate δ18O values extracted from sediments and soils in the watershed range from 10.6‰ in a drainage ditch to 22.3‰ in creek sediments near agriculture fields. The wide range in phosphate δ18O values reflects the variations in land use and application of different fertilizers in this agriculturally dominated landscape. These data suggest that phosphate δ18O can be an effective tool for identifying P sources and understanding phosphate dynamics in estuarine ecosystems.

  10. Phosphate Oxygen Isotopes as a Tracer for Sources and Cycling of Phosphate in San Francisco Bay

    NASA Astrophysics Data System (ADS)

    McLaughlin, K.; Paytan, A.; Kendall, C.; Silva, S.

    2004-12-01

    Phosphorous is an essential macro-nutrient for primary productivity, but tracing sources and cycling of P in marine systems has been difficult to assess because P has only one stable isotope and can not be used as an isotopic tracer. Recently a new technique (McLaughlin et al., 2004) has been developed to track sources and cycling of phosphate in aquatic systems. This approach takes advantage of the strong P-O bond in phosphate, which is resistant to inorganic hydrolysis. The exchange of oxygen isotopes therein only occurs due to intracellular biological cycling. Because the d18O of phosphate will largely be determined by the isotopic composition of the water in which it is being recycled and because the isotopic composition of rivers and oceans is significantly different, the d18O of phosphate may be used as a tracer for different sources of phosphate to an estuarine system which is not phosphate limited. Consequently, the d18O of phosphate may be useful for quantifying the mixing of different sources of phosphate in estuarine systems. We applied this method to enhance our understanding of P sources and cycling in the San Francisco Bay. To this end we conducted four sampling transects from Coyote Creek in the South Bay to the Sacramento and San Joaquin Rivers in the North between October 2002 and August 2004. Phosphate d18O ranged from 10.1 to 20.1 per mil, with highest values at the Golden Gate and lowest at the San Joaquin River. Most of the Bay samples showed strong positive correlations with salinity, water d18O, and the inverse of phosphate concentration, suggesting a simple two-component mixing of oceanic and riverine sources. These data suggest that phosphate d18O can be an effective tool for identifying P point sources and understanding phosphate dynamics in the ecosystem.

  11. Optimization of Porous Pellets for Phosphate Recovery

    EPA Science Inventory

    The poster presents the preliminary adsorption experiment showing that phosphate concentration is decreasing over time as well as presenting the kinetics models that best fit the data collected over 25 days.

  12. Airborne radioactivity surveys for phosphate in Florida

    USGS Publications Warehouse

    Moxham, Robert M.

    1954-01-01

    Airborne radioactivity surveys totaling 5, 600 traverse miles were made in 10 areas in Florida, which were thought to be geologically favorable for deposits of uraniferous phosphate. Abnormal radioactivity was recorded in 8 of the 10 areas surveyed. The anomalies are located in Bradford, Clay, Columbia, DeSoto, Dixie, Lake, Marion, Orange, Sumter, Taylor, and Union Counties. Two of the anomalies were investigated briefly on the ground. One resulted from a deposit of river-pebble phosphate in the Peace River valley; the river-pebble samples contain an average of 0.013 percent equivalent uranium. The other anomaly resulted from outcrops of leached phosphatic rock containing as much as 0. 016 percent equivalent uranium. Several anomalies in other areas were recorded at or near localities where phosphate deposits have been reported.

  13. Airborne radioactivity surveys for phosphate in Florida

    USGS Publications Warehouse

    Moxham, Robert M.

    1953-01-01

    Airborne radioactivity surveys totalling 5,600 traverse miles were made in ten areas in Florida, which were thought to be geologically favorable for the occurrence of uraniferous phosphate deposits. Abnormal radioactivity was recorded in eight of the ten areas surveyed. The anomalies are located in Bradford, Clay, Columbia, DeSoto, Dixie, Lake, Marion, Orange, Sumter, Taylor, and Union Counties. Two of the anomalies were investigated briefly on the ground. One resulted from a deposit of river-pebble phosphate in the Peace River valley; samples of the river pebble contain an average of 0.013 percent equivalent uranium. The other anomaly resulted from outcrops of leached phosphate rock containing as much as 0.016 percent equivalent uranium. Several anomalies in other areas were recorded at or near localities where phosphate deposits have been reported to occur.

  14. Phosphate treatment of hypercalcaemia due to carcinoma.

    PubMed

    Thalassinos, N; Joplin, G F

    1968-10-01

    Thirteen patients with hypercalcaemia due to carcinoma received inorganic phosphate, orally or intravenously, as palliative treatment for their high serum calcium levels. The serum calcium promptly fell in all patients fully treated, and there was a striking clinical improvement in most patients. The blood urea was usually unchanged or became nearer to normal, while the serum phosphate altered variably. Only two of the eight patients who were studied at necropsy had microscopical nephrocalcinosis; corneal calcification was evident in both before phosphate treatment was started.This oral inorganic phosphate (1 gramme thrice daily) is a safe and effective means of treating hypercalcaemia due to carcinoma. An intravenous infusion of 1 gramme over eight hours may sometimes be required initially for patients who are vomiting.

  15. Phosphate Treatment of Hypercalcaemia Due to Carcinoma

    PubMed Central

    Thalassinos, N.; Joplin, G. F.

    1968-01-01

    Thirteen patients with hypercalcaemia due to carcinoma received inorganic phosphate, orally or intravenously, as palliative treatment for their high serum calcium levels. The serum calcium promptly fell in all patients fully treated, and there was a striking clinical improvement in most patients. The blood urea was usually unchanged or became nearer to normal, while the serum phosphate altered variably. Only two of the eight patients who were studied at necropsy had microscopical nephrocalcinosis; corneal calcification was evident in both before phosphate treatment was started. This oral inorganic phosphate (1 gramme thrice daily) is a safe and effective means of treating hypercalcaemia due to carcinoma. An intravenous infusion of 1 gramme over eight hours may sometimes be required initially for patients who are vomiting. PMID:4175670

  16. Enzyme activity in dialkyl phosphate ionic liquids

    SciTech Connect

    Thomas, M.F.; Dunn, J.; Li, L.-L.; Handley-Pendleton, J. M.; van der lelie, D.; Wishart, J. F.

    2011-12-01

    The activity of four metagenomic enzymes and an enzyme cloned from the straw mushroom, Volvariellavolvacea were studied in the following ionic liquids, 1,3-dimethylimidazolium dimethyl phosphate, [mmim][dmp], 1-ethyl-3-methylimidazolium dimethyl phosphate, [emim][dmp], 1-ethyl-3-methylimidazolium diethyl phosphate, [emim][dep] and 1-ethyl-3-methylimidazolium acetate, [emim][OAc]. Activity was determined by analyzing the hydrolysis of para-nitrobenzene carbohydrate derivatives. In general, the enzymes were most active in the dimethyl phosphate ionic liquids, followed by acetate. Generally speaking, activity decreased sharply for concentrations of [emim][dep] above 10% v/v, while the other ionic liquids showed less impact on activity up to 20% v/v.

  17. Isolation of phosphate-solubilizing fungi from phosphate mines and their effect on wheat seedling growth.

    PubMed

    Xiao, Chunqiao; Chi, Ruan; He, Huan; Qiu, Guanzhou; Wang, Dianzuo; Zhang, Wenxue

    2009-11-01

    Three phosphate-solubilizing fungi, identified as Penicillium expansum, Mucor ramosissimus, and Candida krissii, were isolated from phosphate mines (Hubei, People's Republic of China) and characterized. All the isolates demonstrated diverse levels of phosphate-solubilizing capability in National Botanical Research Institute's phosphate growth medium containing rock phosphate as sole phosphate source. Acidification of culture medium seemed to be the main mechanism for rock phosphate solubilization. Indeed, citric acid, oxalic acid, and gluconic acid were shown to be present in the culture medium inoculated with these isolates. Moreover, the isolates produced acid and alkaline phosphatases in culture medium, which may also be helpful for RP solubilization. A strong negative correlation between content of soluble phosphorus and pH (r = - 0.89; p < 0.01) in culture medium was observed in this study. All the isolates promoted growth, soil available phosphorus, phosphorus, and nitrogen uptake of wheat seedling in field soil containing rock phosphate under pot culture conditions, thus demonstrating the capability of these isolates to convert insoluble form of phosphorus into plant available form from rock phosphate, and therefore hold great potential for development as biofertilizers to enhance soil fertility and promote plant growth.

  18. Capturing phosphates with iron enhanced sand filtration.

    PubMed

    Erickson, Andrew J; Gulliver, John S; Weiss, Peter T

    2012-06-01

    Most treatment practices for urban runoff capture pollutants such as phosphorus by either settling or filtration while dissolved phosphorus, typically as phosphates, is untreated. Dissolved phosphorus, however, represents an average 45% of total phosphorus in stormwater runoff and can be more than 95%. In this study, a new stormwater treatment technology to capture phosphate, called the Minnesota Filter, is introduced. The filter comprises iron filings mixed with sand and is tested for phosphate removal from synthetic stormwater. Results indicate that sand mixed with 5% iron filings captures an average of 88% phosphate for at least 200 m of treated depth, which is significantly greater than a sand filter without iron filings. Neither incorporation of iron filings into a sand filter nor capture of phosphates onto iron filings in column experiments had a significant effect on the hydraulic conductivity of the filter at mixtures of 5% or less iron by weight. Field applications with up to 10.7% iron were operated over 1 year without detrimental effects upon hydraulic conductivity. A model is applied and fit to column studies to predict the field performance of iron-enhanced sand filters. The model predictions are verified through the predicted performance of the filters in removing phosphates in field applications. Practical applications of the technology, both existing and proposed, are presented so stormwater managers can begin implementation.

  19. Disorders of Phosphate Homeostasis and Tissue Mineralisation

    PubMed Central

    Bergwitz, Clemens; Jüppner, Harald

    2013-01-01

    Phosphate is absorbed from the diet in the gut, stored as hydroxyapatite in the skeleton, and excreted with the urine. The balance between these compartments determines the circulating phosphate concentration. Fibroblast growth factor 23 (FGF23) has recently been discovered and is part of a previously unrecognised hormonal bone-kidney axis. Phosphate-regulating gene with homologies to endopeptidases on the X chromosome, and dentin matrix protein 1 regulate the expression of FGF23 in osteocytes, which then is O-glycosylated by UDP-N-acetyl-alpha-d-galactosamine: poly-peptide N-acetylgalactosaminyl-transferase 3 and secreted into the circulation. FGF23 binds with high affinity to fibroblast growth factor receptor 1c in the presence of its co-receptor Klotho. It inhibits, either directly or indirectly, reabsorption of phosphate and the synthesis of 1,25-dihydroxy-vita-min-D by the renal proximal tubule and the secretion of parathyroid hormone by the parathyroid glands. Acquired or inborn errors affecting this newly discovered hormonal system can lead to abnormal phosphate homeostasis and/or tissue mineralisation. This chapter will provide an update on the current knowledge of the pathophysiology, the clinical presentation, diagnostic evaluation and therapy of the disorders of phosphate homeostasis and tissue mineralisation. PMID:19494665

  20. The evolution of the marine phosphate reservoir.

    PubMed

    Planavsky, Noah J; Rouxel, Olivier J; Bekker, Andrey; Lalonde, Stefan V; Konhauser, Kurt O; Reinhard, Christopher T; Lyons, Timothy W

    2010-10-28

    Phosphorus is a biolimiting nutrient that has an important role in regulating the burial of organic matter and the redox state of the ocean-atmosphere system. The ratio of phosphorus to iron in iron-oxide-rich sedimentary rocks can be used to track dissolved phosphate concentrations if the dissolved silica concentration of sea water is estimated. Here we present iron and phosphorus concentration ratios from distal hydrothermal sediments and iron formations through time to study the evolution of the marine phosphate reservoir. The data suggest that phosphate concentrations have been relatively constant over the Phanerozoic eon, the past 542 million years (Myr) of Earth's history. In contrast, phosphate concentrations seem to have been elevated in Precambrian oceans. Specifically, there is a peak in phosphorus-to-iron ratios in Neoproterozoic iron formations dating from ∼750 to ∼635 Myr ago, indicating unusually high dissolved phosphate concentrations in the aftermath of widespread, low-latitude 'snowball Earth' glaciations. An enhanced postglacial phosphate flux would have caused high rates of primary productivity and organic carbon burial and a transition to more oxidizing conditions in the ocean and atmosphere. The snowball Earth glaciations and Neoproterozoic oxidation are both suggested as triggers for the evolution and radiation of metazoans. We propose that these two factors are intimately linked; a glacially induced nutrient surplus could have led to an increase in atmospheric oxygen, paving the way for the rise of metazoan life. PMID:20981096

  1. The evolution of the marine phosphate reservoir.

    PubMed

    Planavsky, Noah J; Rouxel, Olivier J; Bekker, Andrey; Lalonde, Stefan V; Konhauser, Kurt O; Reinhard, Christopher T; Lyons, Timothy W

    2010-10-28

    Phosphorus is a biolimiting nutrient that has an important role in regulating the burial of organic matter and the redox state of the ocean-atmosphere system. The ratio of phosphorus to iron in iron-oxide-rich sedimentary rocks can be used to track dissolved phosphate concentrations if the dissolved silica concentration of sea water is estimated. Here we present iron and phosphorus concentration ratios from distal hydrothermal sediments and iron formations through time to study the evolution of the marine phosphate reservoir. The data suggest that phosphate concentrations have been relatively constant over the Phanerozoic eon, the past 542 million years (Myr) of Earth's history. In contrast, phosphate concentrations seem to have been elevated in Precambrian oceans. Specifically, there is a peak in phosphorus-to-iron ratios in Neoproterozoic iron formations dating from ∼750 to ∼635 Myr ago, indicating unusually high dissolved phosphate concentrations in the aftermath of widespread, low-latitude 'snowball Earth' glaciations. An enhanced postglacial phosphate flux would have caused high rates of primary productivity and organic carbon burial and a transition to more oxidizing conditions in the ocean and atmosphere. The snowball Earth glaciations and Neoproterozoic oxidation are both suggested as triggers for the evolution and radiation of metazoans. We propose that these two factors are intimately linked; a glacially induced nutrient surplus could have led to an increase in atmospheric oxygen, paving the way for the rise of metazoan life.

  2. Phosphate separation and recovery from wastewater by novel electrodialysis.

    PubMed

    Zhang, Yang; Desmidt, Evelyn; Van Looveren, Arnaud; Pinoy, Luc; Meesschaert, Boudewijn; Van der Bruggen, Bart

    2013-06-01

    Stimulated by the depletion of phosphate resources, phosphate recovery systems have been studied in recent years. The use of struvite reactors has proven to be an effective phosphate recovery process. However, the struvite reactor effluent still consists of an excessive amount of phosphate that cannot be recovered nor can be directly discharged. In this study, selectrodialysis (SED) was used to improve the efficiency of phosphate recovery from a struvite reactor: SED was implemented in such a way that phosphate from the effluent of an USAB (upflow anaerobic sludge blanket) reactor was transferred to the recycled effluent of a struvite reactor. Prior to the experiments, synthetic water with chloride and phosphate was used to characterize the efficiency of SED for phosphate separation. Results indicate that SED was successful in concentrating phosphate from the feed stream. The initial current efficiency reached 72%, with a satisfying (9 mmol L(-1)) phosphate concentration. In the experiments with the anaerobic effluent as the phosphate source for enrichment of the effluent of the struvite reactor, the phosphate flux was 16 mmol m(-2) h(-1). A cost evaluation shows that 1 kWh electricity can produce 60 g of phosphate by using a full scale stack, with a desalination rate of 95% on the feed wastewater. Finally, a struvite precipitation experiment shows that 93% of phosphate can be recovered. Thus, an integrated SED-struvite reactor process can be used to improve phosphate recovery from wastewater.

  3. Iron-based phosphate binders: do they offer advantages over currently available phosphate binders?

    PubMed Central

    Negri, Armando Luis; Ureña Torres, Pablo Antonio

    2015-01-01

    Increased cardiovascular morbidity and mortality has been associated with the hyperphosphatemia seen in patients with end-stage chronic kidney disease (CKD). Oral phosphate binders are prescribed in these patients to prevent intestinal absorption of dietary phosphate and reduce serum phosphate. In prospective observational cohorts they have shown to decrease all-cause and cardiovascular mortality risk. Different problems have been associated with currently available phosphate binders as positive calcium balance and impaired outcomes with calcium-based phosphate binders or increased costs with non-calcium-based phosphate binders. Iron-based phosphate binders represent a new class of phosphate binders. Several iron-based phosphate binders have undergone testing in clinical trials. Ferric citrate (JTT-751) and sucroferric oxyhydroxide (PA21) are the two iron-based binders that have passed to the clinical field after being found safe and effective in decreasing serum phosphate. Iron from ferric citrate is partially absorbed compared to sucroferric oxyhydroxide. Ferric citrate usage could result in an important reduction in erythropoiesis-stimulating agent (ESA) and IV iron usage, resulting in significant cost savings. Sucroferric oxyhydroxide was effective in lowering serum phosphorus in dialysis patients with similar efficacy to sevelamer carbonate, but with lower pill burden, and better adherence. Ferric citrate may be more suited for the treatment of chronic hyperphosphatemia in CKD patients requiring iron supplements but its use may have been hampered by potential aluminum overload, as citrate facilitates its absorption; sucroferric oxyhydroxide may be more suited for hyperphosphatemic CKD patients not requiring iron supplementation, with low pill burden. PMID:25815172

  4. Kinetics of phosphate limited algal growth.

    PubMed

    Nyholm, N

    1977-04-01

    The kinetics of phosphate limited growth of two green algae Chlorella pyrenoidosa and Selenastrum capricornutum have been studied in chemostats. Several kinetic models which express the specific growth rate as a function of the intracellular phosphorus content have been examined, and one of the models was found to be significantly better than the other models. The principles of this model were described in a recent paper by Nyholm. The kinetics of phosphate uptake have been investigated by adding pulses of phosphate to the chemostats, The uptake by phosphorus deficient cells could be described by Michaelis-Menten kinetics for phosphate concentrations below approximately 500 microng P/liter. Further, with the assumption of a discontinuous adjustment of the uptake rate at the onset of phosphorus deficiency, a complete kinetic model for growth and phosphate removal is proposed. The mean cell size and the contents of chlorophyll a and RNA per unit dry weight have been measured for C. pyrenoidosa as a function of the dilution rate. PMID:856323

  5. Solvothermal synthesis of strontium phosphate chloride nanowire

    NASA Astrophysics Data System (ADS)

    Lam, W. M.; Wong, C. T.; Li, Z. Y.; Luk, K. D. K.; Chan, W. K.; Yang, C.; Chiu, K. Y.; Xu, B.; Lu, W. W.

    2007-08-01

    Strontium phosphate chloride nanowire was synthesized via a solvothermal treatment of strontium tri-polyphosphate and Collin salt in 1,4-dioxane at 150 °C. The effects of 1,4-dioxane concentration on particle morphology, crystallinity and phase purity were investigated in this study. The specimen morphology was analyzed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). When the concentration of 1,4-dioxane was below 10%, micron-sized whisker was the dominant form. At 20-25% concentration of 1,4-dioxane, strontium phosphate chloride single-crystalline nanowire was 31±12 nm in diameter and 1.43±0.6 μm in length with an aspect ratio of 52.28±29.41. X-ray diffraction (XRD) pattern of this nanowire matched with that of strontium phosphate chloride (JCPDS #083-0973). When 1,4-dioxane concentration exceeded 25%, nanorod aggregate was the dominant form instead of nanowire. At 20-25% 1,4-dioxane concentration suitable strontium concentration combine with high chemical potential environment favors the formation of nanowires. By adding 1,4-dioxane impure phase such as β-strontium hydrogen phosphate, nanorod formation was suppressed. This method provides an efficient way to synthesize high aspect ratio strontium phosphate chloride nanowire. It has potential bioactive nanocomposite, high mechanical performance bioactive bone cement filler and fluorescent material applications.

  6. Structural basis for phosphatidylinositol-phosphate biosynthesis

    NASA Astrophysics Data System (ADS)

    Clarke, Oliver B.; Tomasek, David; Jorge, Carla D.; Dufrisne, Meagan Belcher; Kim, Minah; Banerjee, Surajit; Rajashankar, Kanagalaghatta R.; Shapiro, Lawrence; Hendrickson, Wayne A.; Santos, Helena; Mancia, Filippo

    2015-10-01

    Phosphatidylinositol is critical for intracellular signalling and anchoring of carbohydrates and proteins to outer cellular membranes. The defining step in phosphatidylinositol biosynthesis is catalysed by CDP-alcohol phosphotransferases, transmembrane enzymes that use CDP-diacylglycerol as donor substrate for this reaction, and either inositol in eukaryotes or inositol phosphate in prokaryotes as the acceptor alcohol. Here we report the structures of a related enzyme, the phosphatidylinositol-phosphate synthase from Renibacterium salmoninarum, with and without bound CDP-diacylglycerol to 3.6 and 2.5 Å resolution, respectively. These structures reveal the location of the acceptor site, and the molecular determinants of substrate specificity and catalysis. Functional characterization of the 40%-identical ortholog from Mycobacterium tuberculosis, a potential target for the development of novel anti-tuberculosis drugs, supports the proposed mechanism of substrate binding and catalysis. This work therefore provides a structural and functional framework to understand the mechanism of phosphatidylinositol-phosphate biosynthesis.

  7. Structural basis for phosphatidylinositol-phosphate biosynthesis

    PubMed Central

    Clarke, Oliver B.; Tomasek, David; Jorge, Carla D.; Dufrisne, Meagan Belcher; Kim, Minah; Banerjee, Surajit; Rajashankar, Kanagalaghatta R.; Shapiro, Lawrence; Hendrickson, Wayne A.; Santos, Helena; Mancia, Filippo

    2015-01-01

    Phosphatidylinositol is critical for intracellular signalling and anchoring of carbohydrates and proteins to outer cellular membranes. The defining step in phosphatidylinositol biosynthesis is catalysed by CDP-alcohol phosphotransferases, transmembrane enzymes that use CDP-diacylglycerol as donor substrate for this reaction, and either inositol in eukaryotes or inositol phosphate in prokaryotes as the acceptor alcohol. Here we report the structures of a related enzyme, the phosphatidylinositol-phosphate synthase from Renibacterium salmoninarum, with and without bound CDP-diacylglycerol to 3.6 and 2.5 Å resolution, respectively. These structures reveal the location of the acceptor site, and the molecular determinants of substrate specificity and catalysis. Functional characterization of the 40%-identical ortholog from Mycobacterium tuberculosis, a potential target for the development of novel anti-tuberculosis drugs, supports the proposed mechanism of substrate binding and catalysis. This work therefore provides a structural and functional framework to understand the mechanism of phosphatidylinositol-phosphate biosynthesis. PMID:26510127

  8. Inhibition of microbial arsenate reduction by phosphate.

    PubMed

    Slaughter, Deanne C; Macur, Richard E; Inskeep, William P

    2012-03-20

    The ratio of arsenite (As(III)) to arsenate (As(V)) in soils and natural waters is often controlled by the activity of As-transforming microorganisms. Phosphate is a chemical analog to As(V) and, consequently, may competitively inhibit microbial uptake and enzymatic binding of As(V), thus preventing its reduction to the more toxic, mobile, and bioavailable form - As(III). Five As-transforming bacteria isolated either from As-treated soil columns or from As-impacted soils were used to evaluate the effects of phosphate on As(V) reduction and As(III) oxidation. Cultures were initially spiked with various P:As ratios, incubated for approximately 48 h, and analyzed periodically for As(V) and As(III) concentration. Arsenate reduction was inhibited at high P:As ratios and completely suppressed at elevated levels of phosphate (500 and 1,000 μM; P inhibition constant (K(i))∼20-100 μM). While high P:As ratios effectively shut down microbial As(V) reduction, the expression of the arsenate reductase gene (arsC) was not inhibited under these conditions in the As(V)-reducing isolate, Agrobacterium tumefaciens str. 5B. Further, high phosphate ameliorated As(V)-induced cell growth inhibition caused by high (1mM) As pressure. These results indicate that phosphate may inhibit As(V) reduction by impeding As(V) uptake by the cell via phosphate transport systems or by competitively binding to the active site of ArsC. PMID:21741807

  9. Monte Carlo simulations of phosphate polyhedron connectivity in glasses

    SciTech Connect

    ALAM,TODD M.

    2000-01-01

    Monte Carlo simulations of phosphate tetrahedron connectivity distributions in alkali and alkaline earth phosphate glasses are reported. By utilizing a discrete bond model, the distribution of next-nearest neighbor connectivities between phosphate polyhedron for random, alternating and clustering bonding scenarios was evaluated as a function of the relative bond energy difference. The simulated distributions are compared to experimentally observed connectivities reported for solid-state two-dimensional exchange and double-quantum NMR experiments of phosphate glasses. These Monte Carlo simulations demonstrate that the polyhedron connectivity is best described by a random distribution in lithium phosphate and calcium phosphate glasses.

  10. Monte Carlo Simulations of Phosphate Polyhedron Connectivity in Glasses

    SciTech Connect

    ALAM,TODD M.

    1999-12-21

    Monte Carlo simulations of phosphate tetrahedron connectivity distributions in alkali and alkaline earth phosphate glasses are reported. By utilizing a discrete bond model, the distribution of next-nearest neighbor connectivities between phosphate polyhedron for random, alternating and clustering bonding scenarios was evaluated as a function of the relative bond energy difference. The simulated distributions are compared to experimentally observed connectivities reported for solid-state two-dimensional exchange and double-quantum NMR experiments of phosphate glasses. These Monte Carlo simulations demonstrate that the polyhedron connectivity is best described by a random distribution in lithium phosphate and calcium phosphate glasses.

  11. Pumpable/injectable phosphate-bonded ceramics

    DOEpatents

    Singh, Dileep; Wagh, Arun S.; Perry, Lamar; Jeong, Seung-Young

    2001-01-01

    A pumpable ceramic composition is provided comprising an inorganic oxide, potassium phosphate, and an oxide coating material. Also provided is a method for preparing pumpable ceramic-based waste forms comprising selecting inorganic oxides based on solubility, surface area and morphology criteria; mixing the selected oxides with phosphate solution and waste to form a first mixture; combining an additive to the first mixture to create a second mixture; adding water to the second mixture to create a reactive mixture; homogenizing the reactive mixture; and allowing the reactive mixture to cure.

  12. Calcium and phosphate impact cardiovascular risk.

    PubMed

    Heine, Gunnar H; Nangaku, Masaomi; Fliser, Danilo

    2013-04-01

    Non-traditional risk factors substantially contribute to cardiovascular (CV) disease. A deranged calcium-phosphate metabolism-first identified as a major non-traditional CV risk factor in patients with chronic kidney disease-may be implicated in development and progression of CV disease even among individuals with intact renal function. This review thus summarizes epidemiological and experimental data on the role of calcium, phosphate, and its major regulating hormones-parathyroid hormone, calcitriol, and fibroblast growth factor 23-in CV medicine. PMID:23109644

  13. [Phosphate nephropathy: how to avoid it?].

    PubMed

    Bourquin, Vincent; Ponte, Belén; Zellweger, Michael; Levy, Marc; Hadengue, Antoine; Moll, Solange

    2011-11-16

    Colonoscopy is a commonly used procedure for colon cancer screening. The ideal bowel preparation for a good visualization of the colonic mucosa would be effective and well tolerated. Sodium phosphate (NaP) and polyethylen glycol (PEG) are the two most frequently used solutions in this indication. However, although NaP has been described as more effective and better tolerated, it can cause severe acute electrolytes disturbances and, in rare cases, lead to irreversible renal failure, called phosphate nephropathy. NaP should therefore be prescribed with caution and be formally banned for patients with risk factors. PMID:22400350

  14. Phosphate starvation regulon of Salmonella typhimurium.

    PubMed

    Foster, J W; Spector, M P

    1986-05-01

    Several phosphate-starvation-inducible (psi) genetic loci in Salmonella typhimurium were identified by fusing the lacZ gene to psi promoters by using the Mu d1 and Mu d1-8 bacteriophages. Although several different starvation conditions were examined, the psi loci responded solely to phosphate deprivation. A regulatory locus, psiR, was identified as controlling the psiC locus. The psiR locus did not affect the expression of the Escherichia coli phoA locus or any of the other psi loci described.

  15. Potentially Prebiotic Syntheses of Condensed Phosphates

    NASA Technical Reports Server (NTRS)

    Keefe, Anthony D.; Miller, Stanley L.

    1996-01-01

    In view of the importance of a prebiotic source of high energy phosphates, we have investigated a number of potentially prebiotic processes to produce condensed phosphates from orthophosphate and cyclic trimetaphosphate from tripolyphosphate. The reagents investigated include polymerizing nitriles, acid anhydrides, lactones, hexamethylene tetramine and carbon suboxide. A number of these processes give substantial yields of pyrophosphate from orthophosphate and trimetaphosphate from tripolyphosphate. Although these reactions may have been applicable in local areas, they are not sufficiently robust to have been of importance in the prebiotic open ocean.

  16. Dual mechanism of ion permeation through VDAC revealed with inorganic phosphate ions and phosphate metabolites.

    PubMed

    Krammer, Eva-Maria; Vu, Giang Thi; Homblé, Fabrice; Prévost, Martine

    2015-01-01

    In the exchange of metabolites and ions between the mitochondrion and the cytosol, the voltage-dependent anion channel (VDAC) is a key element, as it forms the major transport pathway for these compounds through the mitochondrial outer membrane. Numerous experimental studies have promoted the idea that VDAC acts as a regulator of essential mitochondrial functions. In this study, using a combination of molecular dynamics simulations, free-energy calculations, and electrophysiological measurements, we investigated the transport of ions through VDAC, with a focus on phosphate ions and metabolites. We showed that selectivity of VDAC towards small anions including monovalent phosphates arises from short-lived interactions with positively charged residues scattered throughout the pore. In dramatic contrast, permeation of divalent phosphate ions and phosphate metabolites (AMP and ATP) involves binding sites along a specific translocation pathway. This permeation mechanism offers an explanation for the decrease in VDAC conductance measured in the presence of ATP or AMP at physiological salt concentration. The binding sites occur at similar locations for the divalent phosphate ions, AMP and ATP, and contain identical basic residues. ATP features a marked affinity for a central region of the pore lined by two lysines and one arginine of the N-terminal helix. This cluster of residues together with a few other basic amino acids forms a "charged brush" which facilitates the passage of the anionic metabolites through the pore. All of this reveals that VDAC controls the transport of the inorganic phosphates and phosphate metabolites studied here through two different mechanisms.

  17. Synthesis of arabinitol 1-phosphate and its use for characterization of arabinitol-phosphate dehydrogenase.

    PubMed

    Soroka, Nikolai V; Kulminskaya, Anna A; Eneyskaya, Elena V; Shabalin, Konstantin A; Uffimtcev, Andrei V; Povelainen, Mira; Miasnikov, Andrei N; Neustroev, Kirill N

    2005-03-21

    D-arabinitol 1-phosphate (Ara-ol1-P), a substrate for D-arabinitol-phosphate dehydrogenase (APDH), was chemically synthesized from D-arabinonic acid in five steps (O-acetylation, chlorination, reduction, phosphorylation, and de-O-acetylation). Ara-ol1-P was used as a substrate for the characterization of APDH from Bacillus halodurans. APDH converts Ara-ol1-P to xylulose 5-phosphate in the oxidative reaction; both NAD(+) and NADP(+) were accepted as co-factors. Kinetic parameters for the oxidative and reductive reactions are consistent with a ternary complex mechanism.

  18. Attenuation of Phosphate Starvation Responses by Phosphite in Arabidopsis1

    PubMed Central

    Ticconi, Carla A.; Delatorre, Carla A.; Abel, Steffen

    2001-01-01

    When inorganic phosphate is limiting, Arabidopsis has the facultative ability to metabolize exogenous nucleic acid substrates, which we utilized previously to identify insensitive phosphate starvation response mutants in a conditional genetic screen. In this study, we examined the effect of the phosphate analog, phosphite (Phi), on molecular and morphological responses to phosphate starvation. Phi significantly inhibited plant growth on phosphate-sufficient (2 mm) and nucleic acid-containing (2 mm phosphorus) media at concentrations higher than 2.5 mm. However, with respect to suppressing typical responses to phosphate limitation, Phi effects were very similar to those of phosphate. Phosphate starvation responses, which we examined and found to be almost identically affected by both anions, included changes in: (a) the root-to-shoot ratio; (b) root hair formation; (c) anthocyanin accumulation; (d) the activities of phosphate starvation-inducible nucleolytic enzymes, including ribonuclease, phosphodiesterase, and acid phosphatase; and (e) steady-state mRNA levels of phosphate starvation-inducible genes. It is important that induction of primary auxin response genes by indole-3-acetic acid in the presence of growth-inhibitory Phi concentrations suggests that Phi selectively inhibits phosphate starvation responses. Thus, the use of Phi may allow further dissection of phosphate signaling by genetic selection for constitutive phosphate starvation response mutants on media containing organophosphates as the only source of phosphorus. PMID:11706178

  19. Isothermal Damage and Fatigue Behavior of SCS-6/Timetal 21S [0/90](Sub S) Composite at 650 Deg C

    NASA Technical Reports Server (NTRS)

    Castelli, Michael G.

    1994-01-01

    The isothermal fatigue damage and life behaviors of SCS-6/Timetal 21S (0/90)s were investigated at 650 C. Strain ratcheting and degradation of the composite's static elastic modulus were carefully monitored as functions of cycles to indicate damage progression. Extensive fractographic and metallographic analyses were conducted to determine damage/failure mechanisms. Resulting fatigue lives show considerable reductions in comparison to (0) reinforced titanium matrix composites subjected to comparable conditions. Notable stiffness degradations were found to occur after the first cycle of loading, even at relatively low maximum stress levels, where cyclic lives are greater than 25,000 cycles. This was attributed to the extremely weak fiber/matrix bond which fails under relatively low transverse loads. Stiffness degradations incurred on first cycle loadings and degradations thereafter were found to increase with increasing maximum stress. Environmental effects associated with oxidation of the (90) fiber interfaces clearly played a role in the damage mechanisms as fracture surfaces revealed environment assisted matrix cracking along the (90) fibers. Metallographic analysis indicated that all observable matrix fatigue cracks initiated at the (90) fiber/matrix interfaces. Global de-bonding in the loading direction was found along the (90) fibers. No surface initiated cracks were evident and minimal if any (0) fiber cracking was visible.

  20. Multiple Gingival Recession Defects Treated with Coronally Advanced Flap and Either the VISTA Technique Enhanced with GEM 21S or Periosteal Pedicle Graft: A 9-Month Clinical Study.

    PubMed

    Dandu, Shruti Raju; Murthy, K Raja

    2016-01-01

    The objective of this study was to clinically evaluate and compare the efficacy of the vestibular incision subperiosteal tunnel access (VISTA) technique using Bio-Gide (Geistlich) membrane enhanced with GEM 21S (Osteohealth) with periosteal pedicle graft (PPG) using a coronally advanced flap. Multiple gingival recession sites in 15 individuals were randomly assigned either to experimental site A (VISTA) or experimental site B (PPG) in a split-mouth design. The clinical parameters were recorded at baseline and 9 months postoperatively. Repeated measures analysis of variance with post hoc Bonferroni correction and paired t test were used to assess statistical significance (P < .05). Mean recession depth significantly decreased from 4.21 ± 1.08 mm (presurgery) to 0.61 ± 0.92 mm (9 months) with VISTA (87.37 ± 17.78% root coverage) and from 4.17 ± 1.18 mm (presurgery) to 1.16 ± 0.92 mm (9 months) with PPG (71.84 ± 19.25% root coverage). Width of keratinized tissue and clinical attachment gain were significantly higher in the VISTA group compared with the PPG group. Within the limits of the study both VISTA and PPG groups resulted in a significant amount of root coverage. The VISTA technique was less invasive and required minimal time and clinical maneuvering. It also resulted in a superior esthetic outcome. PMID:26901301

  1. Multiple Gingival Recession Defects Treated with Coronally Advanced Flap and Either the VISTA Technique Enhanced with GEM 21S or Periosteal Pedicle Graft: A 9-Month Clinical Study.

    PubMed

    Dandu, Shruti Raju; Murthy, K Raja

    2016-01-01

    The objective of this study was to clinically evaluate and compare the efficacy of the vestibular incision subperiosteal tunnel access (VISTA) technique using Bio-Gide (Geistlich) membrane enhanced with GEM 21S (Osteohealth) with periosteal pedicle graft (PPG) using a coronally advanced flap. Multiple gingival recession sites in 15 individuals were randomly assigned either to experimental site A (VISTA) or experimental site B (PPG) in a split-mouth design. The clinical parameters were recorded at baseline and 9 months postoperatively. Repeated measures analysis of variance with post hoc Bonferroni correction and paired t test were used to assess statistical significance (P < .05). Mean recession depth significantly decreased from 4.21 ± 1.08 mm (presurgery) to 0.61 ± 0.92 mm (9 months) with VISTA (87.37 ± 17.78% root coverage) and from 4.17 ± 1.18 mm (presurgery) to 1.16 ± 0.92 mm (9 months) with PPG (71.84 ± 19.25% root coverage). Width of keratinized tissue and clinical attachment gain were significantly higher in the VISTA group compared with the PPG group. Within the limits of the study both VISTA and PPG groups resulted in a significant amount of root coverage. The VISTA technique was less invasive and required minimal time and clinical maneuvering. It also resulted in a superior esthetic outcome.

  2. Interaction of cadmium with phosphate on goethite

    SciTech Connect

    Venema, P.; Hiemstra, T.; Riemsdijk, W.H. van

    1997-08-01

    Interactions between different ions are of importance in understanding chemical processes in natural systems. In this study simultaneous adsorption of phosphate and cadmium on goethite is studied in detail. The charge distribution (CD)-multisite complexation (MUSIC) model has been successful in describing extended data sets of cadmium adsorption and phosphate adsorption on goethite. In this study, the parameters of this model for these two data sets were combined to describe a new data set of simultaneous adsorption of cadmium and phosphate on goethite. Attention is focused on the surface speciation of cadmium. With the extra information that can be obtained from the interaction experiments, the cadmium adsorption model is refined. For a perfect description of the data, the singly coordinated surface groups at the 110 face of goethite were assumed to form both monodentate and bidentate surface species with cadmium. The CD-MUSIC model is able to describe data sets of both simultaneous and single adsorption of cadmium and phosphate with the same parameters. The model calculations confirmed the idea that only singly coordinated surface groups are reactive for specific ion binding.

  3. Insights from Genetic Disorders of Phosphate Homeostasis

    PubMed Central

    Christov, Marta; Jüppner, Harald

    2013-01-01

    The molecular identification and characterization of genetic defects leading to a number of rare inherited or acquired disorders affecting phosphate homeostasis has added tremendous detail to our understanding of the regulation of phosphate balance. The identification of the key phosphate-regulating hormone, fibroblast growth factor 23 (FGF23), as well as other molecules that control its production, such as the glycosyltransferase GALNT3, the endopeptidase PHEX and the matrix protein DMP1, and molecules that function as downstream effectors of FGF23, such as the longevity factor Klotho and the phosphate transporters NPT2a and NPT2c, has permitted us to understand the elegant and complex interplay that exists between the kidneys, bone, parathyroid, and gut. Such insights from genetic disorders have allowed not only the design of potent targeted therapies for some of these rare genetic disorders, such as using anti-FGF23 antibodies for treatment of X-linked hypophosphatemic rickets, but also have led to clinically relevant observations related to the dysregulation of mineral ion homeostasis in chronic kidney disease. Thus, we are able to leverage our knowledge of rare human disorders affecting only few individuals, to understand and potentially treat disease processes that affect millions of patients. PMID:23465501

  4. 21 CFR 137.175 - Phosphated flour.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Phosphated flour. 137.175 Section 137.175 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION CEREAL FLOURS AND RELATED PRODUCTS Requirements for Specific Standardized Cereal Flours...

  5. IN-SITU MINING OF PHOSPHATE ORES

    SciTech Connect

    H. El-Shall; R. Stana; A. El-Midany; S. Malekzadah

    2004-12-17

    Presently the mining of Florida phosphate requires the movement of over a 100-ton of materials (overburden, sand, clay) for every ton of phosphate concentrate recovered. Not only is this energy intensive, but it also causes significant stress on the environment. In 2003, the Department of Energy solicited ideas for innovative mining ideas that could significantly improve the efficiency of mining. An award was made to the University of Florida Engineering Research Center to evaluate the in situ mining of phosphates using an aqueous CO{sub 2} solution. Tests were carried out in a 15.2 cm (6-inch) diameter column, 1.83 meter (6 feet) long at pressures up to 117.2 kg/cm{sup 2} (40 psi). Results to date demonstrate that initially the MgO is leached from the ore and then the phosphate. While the tests are continuing, so far they have not demonstrated P{sub 2}O{sub 5} concentrations that are economically attractive.

  6. An Experiment to Quantitate Organically Bound Phosphate.

    ERIC Educational Resources Information Center

    Palmer, Richard E.

    1985-01-01

    Describes quick and easy experiments that yield quantitative information on a variety of levels, emphasize the concept of experimental controls, and integrate the experimental with the theoretical using the organic phosphates as the experimental system. Background information, list of materials needed, and procedures used are included. (JN)

  7. 21 CFR 184.1301 - Ferric phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ferric phosphate. 184.1301 Section 184.1301 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed...

  8. 21 CFR 184.1301 - Ferric phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Ferric phosphate. 184.1301 Section 184.1301 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing...

  9. 21 CFR 184.1301 - Ferric phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ferric phosphate. 184.1301 Section 184.1301 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing...

  10. 21 CFR 184.1301 - Ferric phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ferric phosphate. 184.1301 Section 184.1301 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing...

  11. Mixed-metal templated phosphate phases

    SciTech Connect

    Nenoff, T.M.; Jackson, N.B.; Thoma, S.G.; Kohler, S.D.; Harrison, W.T.A.

    1997-08-01

    In an effort to direct the structure formation and subsequently the catalytic properties of novel materials, both organic molecules and transition metals have been systematically incorporated into zinc phosphate materials, and various transition metals in zirconium phosphate materials. The resultant phases in the Zn/P experiments are determined not by the organic template, but by the type and stoichiometric amount of metal incorporated and by the organic template`s anion. Furthermore, only one of the phases, a Ni/Zn/P, shows any acidic catalytic behavior. Similarly, the transition metals incorporated in stoichiometric amounts into the catalytically active novel zirconium phosphate are highly structure directing. Their presence inhibits the formation of the phosphate phase, instead promoting the formation of tetragonal ZrO{sub 2}. The catalytic activity of the products are greatly diminished from the baseline material. The synthesis and characterization methods for each phase will be presented. Characterization techniques employed include single-crystal and powder X-ray diffraction, magnetic susceptibility, thermal analysis, DCP and FTIR.

  12. TUCS/phosphate mineralization of actinides

    SciTech Connect

    Nash, K.L.

    1997-10-01

    This program has as its objective the development of a new technology that combines cation exchange and mineralization to reduce the concentration of heavy metals (in particular actinides) in groundwaters. The treatment regimen must be compatible with the groundwater and soil, potentially using groundwater/soil components to aid in the immobilization process. The delivery system (probably a water-soluble chelating agent) should first concentrate the radionuclides then release the precipitating anion, which forms thermodynamically stable mineral phases, either with the target metal ions alone or in combination with matrix cations. This approach should generate thermodynamically stable mineral phases resistant to weathering. The chelating agent should decompose spontaneously with time, release the mineralizing agent, and leave a residue that does not interfere with mineral formation. For the actinides, the ideal compound probably will release phosphate, as actinide phosphate mineral phases are among the least soluble species for these metals. The most promising means of delivering the precipitant would be to use a water-soluble, hydrolytically unstable complexant that functions in the initial stages as a cation exchanger to concentrate the metal ions. As it decomposes, the chelating agent releases phosphate to foster formation of crystalline mineral phases. Because it involves only the application of inexpensive reagents, the method of phosphate mineralization promises to be an economical alternative for in situ immobilization of radionuclides (actinides in particular). The method relies on the inherent (thermodynamic) stability of actinide mineral phases.

  13. Phosphate adsorption on granular palygorskite: batch and column studies.

    PubMed

    Fangqun, Gan; Jianmin, Zhou; Huoyan, Wang; Changwen, Du; Wenzhao, Zhang; Xiaoqin, Chen

    2011-02-01

    A method to prepare granular palygorskite (GPA) was put forward in this research, and its potential use to remove phosphate species from aqueous solution was assessed. Batch experiments were performed to study the adsorption equilibrium and influence of contact time and pH on the adsorption and desorption of phosphate onto GPA in water. The maximum phosphate adsorption capacity of GPA was 13.1 mg/g. Kinetic data revealed that more than 90% of phosphate was adsorbed onto GPA within 2 hours. Phosphate adsorption capacity was 0.10 mg/g in column experiments, and co-existing anions could decrease phosphate removal. The saturated column was regenerated by 0.2 mol/L sodium hydroxide, and the GPA could be reused in phosphate removal. The data obtained from both batch and column studies indicated that GPA could be used effectively to remove phosphate from water.

  14. 21 CFR 582.5697 - Riboflavin-5-phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5697 Riboflavin-5-phosphate. (a) Product. Riboflavin-5-phosphate. (b) Conditions of...

  15. 21 CFR 582.5697 - Riboflavin-5-phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5697 Riboflavin-5-phosphate. (a) Product. Riboflavin-5-phosphate. (b) Conditions of...

  16. 21 CFR 582.5697 - Riboflavin-5-phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5697 Riboflavin-5-phosphate. (a) Product. Riboflavin-5-phosphate. (b) Conditions of...

  17. Genetics Home Reference: pyridoxal 5'-phosphate-dependent epilepsy

    MedlinePlus

    ... Clayton PT, Baumgartner MR, Steinmann B, Bast T, Wolf NI, Zschocke J. Pyridoxal 5'-phosphate may be ... Clayton PT, Baumgartner MR, Steinmann B, Bast T, Wolf NI, Zschocke J. Pyridoxal 5'-phosphate may be ...

  18. Phosphates in some missouri refractory clays

    USGS Publications Warehouse

    Hall, R.B.; Foord, E.E.; Keller, D.J.; Keller, W.D.

    1997-01-01

    This paper describes in detail phosphate minerals occurring in refractory clays of Missouri and their effect on the refractory degree of the clays. The minerals identified include carbonate-fluorapatite (francolite), crandallite, goyazite, wavellite, variscite and strengite. It is emphasized that these phosphates occur only in local isolated concentrations, and not generally in Missouri refractory clays. The Missouri fireclay region comprises 2 districts, northern and southern, separated by the Missouri River In this region, clay constitutes a major part of the Lower Pennsylvanian Cheltenham Formation. The original Cheltenham mud was an argillic residue derived from leaching and dissolution of pre-Pennsylvanian carbonates. The mud accumulated on a karstic erosion surface truncating the pre-Cheltenham rocks. Fireclays of the northern district consist mainly of poorly ordered kaolinite, with variable but minor amounts of illite, chlorite and fine-grained detrital quartz. Clays of the southern district were subjected to extreme leaching that produced well-ordered kaolinite flint clays. Local desilication formed pockets of diaspora, or more commonly, kaolinite, with oolite-like nubs or burls of diaspore ("burley" clay). The phosphate-bearing materials have been studied by X-ray diffraction (XRD), scanning electron microscopy-energy dispersive spectral analysis (SEM-EDS) and chemical analysis. Calcian goyazite was identified in a sample of diaspore, and francolite in a sample of flint clay. A veinlet of wavellite occurs in flint clay at one locality, and a veinlet of variscite-strengite at another locality. The Missouri flint-clay-hosted francolite could not have formed in the same manner as marine francolite The evidence suggests that the Cheltenham francolite precipitated from ion complexes in pore water nearly simultaneously with crystallization of kaolinite flint clay from an alumina-silica gel. Calcian goyazite is an early diagenetic addition to its diaspore host

  19. Iron phosphate glass containing simulated fast reactor waste: Characterization and comparison with pristine iron phosphate glass

    NASA Astrophysics Data System (ADS)

    Joseph, Kitheri; Asuvathraman, R.; Venkata Krishnan, R.; Ravindran, T. R.; Govindaraj, R.; Govindan Kutty, K. V.; Vasudeva Rao, P. R.

    2014-09-01

    Detailed characterization was carried out on an iron phosphate glass waste form containing 20 wt.% of a simulated nuclear waste. High temperature viscosity measurement was carried out by the rotating spindle method. The Fe3+/Fe ratio and structure of this waste loaded iron phosphate glass was investigated using Mössbauer and Raman spectroscopy respectively. Specific heat measurement was carried out in the temperature range of 300-700 K using differential scanning calorimeter. Isoconversional kinetic analysis was employed to understand the crystallization behavior of the waste loaded iron phosphate glass. The glass forming ability and glass stability of the waste loaded glass were also evaluated. All the measured properties of the waste loaded glass were compared with the characteristics of pristine iron phosphate glass.

  20. Static friction of porous bioceramic beta-TCP on intestinal mucus films.

    PubMed

    Wang, Xin-Yu; Han, Ying-Chao; Jiang, Xin; Dai, Hong-Lian; Li, Shi-Pu

    2006-09-01

    The static friction behavior between a porous bioceramic material and an intestinal mucus film was investigated in order to develop a new intestine robotic endoscope. Here, the friction couple is porous beta-tricalcium phosphate (beta-TCP) and an artificial intestine mucus film. The effect of pore size of the beta-TCP material on the friction behavior is investigated. The results illustrated that in this friction system there is a relatively small normal force upon the intestinal mucus film of the intestine wall during locomotion. The maximum static friction force in this friction couple varies with the pore size of the porous beta-TCP material.

  1. 21 CFR 182.6085 - Sodium acid phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium acid phosphate. 182.6085 Section 182.6085 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Sodium acid phosphate. (a) Product. Sodium acid phosphate. (b) Conditions of use. This substance...

  2. 21 CFR 522.1883 - Prednisolone sodium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Prednisolone sodium phosphate. 522.1883 Section... § 522.1883 Prednisolone sodium phosphate. (a) Specifications. Each milliliter of solution contains 20 milligrams (mg) prednisolone sodium phosphate (equivalent to 14.88 mg of prednisolone). (b) Sponsor. See...

  3. 21 CFR 522.1883 - Prednisolone sodium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Prednisolone sodium phosphate. 522.1883 Section... § 522.1883 Prednisolone sodium phosphate. (a) Specifications. Each milliliter of solution contains 20 milligrams (mg) prednisolone sodium phosphate (equivalent to 14.88 mg of prednisolone). (b) Sponsor. See...

  4. 40 CFR 721.3080 - Substituted phosphate ester (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted phosphate ester (generic... Substances § 721.3080 Substituted phosphate ester (generic). (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as a substituted phosphate...

  5. 40 CFR 721.10302 - Zinc ammonium phosphate (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Zinc ammonium phosphate (generic). 721... Substances § 721.10302 Zinc ammonium phosphate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as zinc ammonium phosphate (PMN...

  6. 40 CFR 721.10302 - Zinc ammonium phosphate (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Zinc ammonium phosphate (generic). 721... Substances § 721.10302 Zinc ammonium phosphate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as zinc ammonium phosphate (PMN...

  7. 40 CFR 721.10302 - Zinc ammonium phosphate (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Zinc ammonium phosphate (generic). 721... Substances § 721.10302 Zinc ammonium phosphate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as zinc ammonium phosphate (PMN...

  8. 40 CFR 721.10357 - Iron, citrate phosphate potassium complexes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Iron, citrate phosphate potassium... Specific Chemical Substances § 721.10357 Iron, citrate phosphate potassium complexes. (a) Chemical..., citrate phosphate potassium complexes (PMN P-09-382; CAS No. 120579-31-9) is subject to reporting...

  9. 40 CFR 721.10357 - Iron, citrate phosphate potassium complexes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Iron, citrate phosphate potassium... Specific Chemical Substances § 721.10357 Iron, citrate phosphate potassium complexes. (a) Chemical..., citrate phosphate potassium complexes (PMN P-09-382; CAS No. 120579-31-9) is subject to reporting...

  10. 40 CFR 721.10357 - Iron, citrate phosphate potassium complexes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Iron, citrate phosphate potassium... Specific Chemical Substances § 721.10357 Iron, citrate phosphate potassium complexes. (a) Chemical..., citrate phosphate potassium complexes (PMN P-09-382; CAS No. 120579-31-9) is subject to reporting...

  11. 21 CFR 582.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium aluminum phosphate. 582.1781 Section 582.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate. (b) Conditions...

  12. 21 CFR 182.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium aluminum phosphate. 182.1781 Section 182.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate....

  13. 21 CFR 582.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Sodium aluminum phosphate. 582.1781 Section 582.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate. (b) Conditions...

  14. 21 CFR 582.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Sodium aluminum phosphate. 582.1781 Section 582.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate. (b) Conditions...

  15. 21 CFR 582.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Sodium aluminum phosphate. 582.1781 Section 582.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate. (b) Conditions...

  16. 21 CFR 182.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium aluminum phosphate. 182.1781 Section 182.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate....

  17. 21 CFR 182.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium aluminum phosphate. 182.1781 Section 182...) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Multiple Purpose GRAS Food Substances § 182.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate. (b) Conditions of use. This substance is...

  18. 21 CFR 582.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Sodium aluminum phosphate. 582.1781 Section 582.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate. (b) Conditions...

  19. 21 CFR 182.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium aluminum phosphate. 182.1781 Section 182.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate....

  20. 21 CFR 182.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium aluminum phosphate. 182.1781 Section 182.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate....

  1. Determination of Phosphates by the Gravimetric Quimociac Technique

    ERIC Educational Resources Information Center

    Shaver, Lee Alan

    2008-01-01

    The determination of phosphates by the classic quimociac gravimetric technique was used successfully as a laboratory experiment in our undergraduate analytical chemistry course. Phosphate-containing compounds are dissolved in acid and converted to soluble orthophosphate ion (PO[subscript 4][superscript 3-]). The soluble phosphate is easily…

  2. 21 CFR 862.1720 - Triose phosphate isomerase test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... isomerase test system is a device intended to measure the activity of the enzyme triose phosphate isomerase in erythrocytes (red blood cells). Triose phosphate isomerase is an enzyme important in glycolysis... this device are used in the diagnosis and treatment of congenital triose phosphate isomerase...

  3. 21 CFR 862.1720 - Triose phosphate isomerase test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... isomerase test system is a device intended to measure the activity of the enzyme triose phosphate isomerase in erythrocytes (red blood cells). Triose phosphate isomerase is an enzyme important in glycolysis... this device are used in the diagnosis and treatment of congenital triose phosphate isomerase...

  4. 21 CFR 862.1720 - Triose phosphate isomerase test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... isomerase test system is a device intended to measure the activity of the enzyme triose phosphate isomerase in erythrocytes (red blood cells). Triose phosphate isomerase is an enzyme important in glycolysis... this device are used in the diagnosis and treatment of congenital triose phosphate isomerase...

  5. 21 CFR 862.1720 - Triose phosphate isomerase test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... isomerase test system is a device intended to measure the activity of the enzyme triose phosphate isomerase in erythrocytes (red blood cells). Triose phosphate isomerase is an enzyme important in glycolysis... this device are used in the diagnosis and treatment of congenital triose phosphate isomerase...

  6. 21 CFR 862.1720 - Triose phosphate isomerase test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... isomerase test system is a device intended to measure the activity of the enzyme triose phosphate isomerase in erythrocytes (red blood cells). Triose phosphate isomerase is an enzyme important in glycolysis... this device are used in the diagnosis and treatment of congenital triose phosphate isomerase...

  7. 21 CFR 182.6215 - Monobasic calcium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Monobasic calcium phosphate. 182.6215 Section 182.6215 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....6215 Monobasic calcium phosphate. (a) Product. Monobasic calcium phosphate. (b) Conditions of use....

  8. 21 CFR 582.6215 - Monobasic calcium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Monobasic calcium phosphate. 582.6215 Section 582.6215 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....6215 Monobasic calcium phosphate. (a) Product. Monobasic calcium phosphate. (b) Conditions of use....

  9. 21 CFR 582.6215 - Monobasic calcium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Monobasic calcium phosphate. 582.6215 Section 582.6215 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....6215 Monobasic calcium phosphate. (a) Product. Monobasic calcium phosphate. (b) Conditions of use....

  10. 21 CFR 582.6215 - Monobasic calcium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Monobasic calcium phosphate. 582.6215 Section 582.6215 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....6215 Monobasic calcium phosphate. (a) Product. Monobasic calcium phosphate. (b) Conditions of use....

  11. 21 CFR 182.6215 - Monobasic calcium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Monobasic calcium phosphate. 182.6215 Section 182...) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Sequestrants 1 § 182.6215 Monobasic calcium phosphate. (a) Product. Monobasic calcium phosphate. (b) Conditions of use. This substance is generally recognized as safe when...

  12. 21 CFR 182.6215 - Monobasic calcium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Monobasic calcium phosphate. 182.6215 Section 182.6215 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....6215 Monobasic calcium phosphate. (a) Product. Monobasic calcium phosphate. (b) Conditions of use....

  13. 21 CFR 582.6215 - Monobasic calcium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Monobasic calcium phosphate. 582.6215 Section 582.6215 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....6215 Monobasic calcium phosphate. (a) Product. Monobasic calcium phosphate. (b) Conditions of use....

  14. 21 CFR 182.6215 - Monobasic calcium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Monobasic calcium phosphate. 182.6215 Section 182.6215 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....6215 Monobasic calcium phosphate. (a) Product. Monobasic calcium phosphate. (b) Conditions of use....

  15. 21 CFR 182.6215 - Monobasic calcium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Monobasic calcium phosphate. 182.6215 Section 182.6215 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....6215 Monobasic calcium phosphate. (a) Product. Monobasic calcium phosphate. (b) Conditions of use....

  16. 21 CFR 582.6215 - Monobasic calcium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Monobasic calcium phosphate. 582.6215 Section 582.6215 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....6215 Monobasic calcium phosphate. (a) Product. Monobasic calcium phosphate. (b) Conditions of use....

  17. 40 CFR 721.10332 - Lithium metal phosphate (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Lithium metal phosphate (generic). 721... Substances § 721.10332 Lithium metal phosphate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as lithium metal phosphate (PMN...

  18. 40 CFR 721.10332 - Lithium metal phosphate (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Lithium metal phosphate (generic). 721... Substances § 721.10332 Lithium metal phosphate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as lithium metal phosphate (PMN...

  19. 40 CFR 721.10332 - Lithium metal phosphate (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Lithium metal phosphate (generic). 721... Substances § 721.10332 Lithium metal phosphate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as lithium metal phosphate (PMN...

  20. 40 CFR 721.10046 - Polyaromatic amine phosphate (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polyaromatic amine phosphate (generic... Specific Chemical Substances § 721.10046 Polyaromatic amine phosphate (generic). (a) Chemical substance and... amine phosphate (PMN P-02-747) is subject to reporting under this section for the significant new...

  1. 21 CFR 522.1883 - Prednisolone sodium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Prednisolone sodium phosphate. 522.1883 Section... § 522.1883 Prednisolone sodium phosphate. (a) Specifications. Each milliliter of solution contains 20 milligrams (mg) prednisolone sodium phosphate (equivalent to 14.88 mg of prednisolone). (b) Sponsor. See...

  2. 40 CFR 721.10213 - Polyether polyester copolymer phosphate (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... phosphate (generic). 721.10213 Section 721.10213 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10213 Polyether polyester copolymer phosphate (generic). (a) Chemical... as polyether polyester copolymer phosphate (PMN P-09-253) is subject to reporting under this...

  3. 40 CFR 721.10046 - Polyaromatic amine phosphate (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Polyaromatic amine phosphate (generic... Specific Chemical Substances § 721.10046 Polyaromatic amine phosphate (generic). (a) Chemical substance and... amine phosphate (PMN P-02-747) is subject to reporting under this section for the significant new...

  4. 40 CFR 721.643 - Ethoxylated alcohol, phosphated, amine salt.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Ethoxylated alcohol, phosphated, amine... Specific Chemical Substances § 721.643 Ethoxylated alcohol, phosphated, amine salt. (a) Chemical substance... alcohol, phosphated, amine salt (PMN P-96-1478) is subject to reporting under this section for...

  5. 40 CFR 721.643 - Ethoxylated alcohol, phosphated, amine salt.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Ethoxylated alcohol, phosphated, amine... Specific Chemical Substances § 721.643 Ethoxylated alcohol, phosphated, amine salt. (a) Chemical substance... alcohol, phosphated, amine salt (PMN P-96-1478) is subject to reporting under this section for...

  6. 40 CFR 721.643 - Ethoxylated alcohol, phosphated, amine salt.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Ethoxylated alcohol, phosphated, amine... Specific Chemical Substances § 721.643 Ethoxylated alcohol, phosphated, amine salt. (a) Chemical substance... alcohol, phosphated, amine salt (PMN P-96-1478) is subject to reporting under this section for...

  7. 40 CFR 721.643 - Ethoxylated alcohol, phosphated, amine salt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Ethoxylated alcohol, phosphated, amine... Specific Chemical Substances § 721.643 Ethoxylated alcohol, phosphated, amine salt. (a) Chemical substance... alcohol, phosphated, amine salt (PMN P-96-1478) is subject to reporting under this section for...

  8. 40 CFR 721.643 - Ethoxylated alcohol, phosphated, amine salt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Ethoxylated alcohol, phosphated, amine... Specific Chemical Substances § 721.643 Ethoxylated alcohol, phosphated, amine salt. (a) Chemical substance... alcohol, phosphated, amine salt (PMN P-96-1478) is subject to reporting under this section for...

  9. Phosphate Ions - Does Exposure Lead to Degradation of Cementitious Materials?

    SciTech Connect

    Naus, Dan J; Mattus, Catherine H; Dole, Leslie Robert

    2008-01-01

    An assessment of the potential effects of phosphate ions on cementitious materials was made through a review of the literature, contacts with concrete research personnel, and conduct of a "bench-scale" laboratory investigation. Results indicate that no harmful interactions occur between phosphate ions and cememtitious materials unless phosphates are present in form of phosphoric acid.

  10. Dominant oceanic bacteria secure phosphate using a large extracellular buffer.

    PubMed

    Zubkov, Mikhail V; Martin, Adrian P; Hartmann, Manuela; Grob, Carolina; Scanlan, David J

    2015-07-22

    The ubiquitous SAR11 and Prochlorococcus bacteria manage to maintain a sufficient supply of phosphate in phosphate-poor surface waters of the North Atlantic subtropical gyre. Furthermore, it seems that their phosphate uptake may counter-intuitively be lower in more productive tropical waters, as if their cellular demand for phosphate decreases there. By flow sorting (33)P-phosphate-pulsed (32)P-phosphate-chased cells, we demonstrate that both Prochlorococcus and SAR11 cells exploit an extracellular buffer of labile phosphate up to 5-40 times larger than the amount of phosphate required to replicate their chromosomes. Mathematical modelling is shown to support this conclusion. The fuller the buffer the slower the cellular uptake of phosphate, to the point that in phosphate-replete tropical waters, cells can saturate their buffer and their phosphate uptake becomes marginal. Hence, buffer stocking is a generic, growth-securing adaptation for SAR11 and Prochlorococcus bacteria, which lack internal reserves to reduce their dependency on bioavailable ambient phosphate.

  11. 21 CFR 582.6085 - Sodium acid phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium acid phosphate. 582.6085 Section 582.6085 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Sodium acid phosphate. (a) Product. Sodium acid phosphate. (b) Conditions of use. This substance...

  12. 21 CFR 182.6085 - Sodium acid phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium acid phosphate. 182.6085 Section 182.6085 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Sodium acid phosphate. (a) Product. Sodium acid phosphate. (b) Conditions of use. This substance...

  13. 21 CFR 582.6085 - Sodium acid phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Sodium acid phosphate. 582.6085 Section 582.6085 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Sodium acid phosphate. (a) Product. Sodium acid phosphate. (b) Conditions of use. This substance...

  14. 21 CFR 582.6085 - Sodium acid phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Sodium acid phosphate. 582.6085 Section 582.6085 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Sodium acid phosphate. (a) Product. Sodium acid phosphate. (b) Conditions of use. This substance...

  15. 21 CFR 182.6085 - Sodium acid phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium acid phosphate. 182.6085 Section 182.6085...) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Sequestrants 1 § 182.6085 Sodium acid phosphate. (a) Product. Sodium acid phosphate. (b) Conditions of use. This substance is generally recognized as safe when used...

  16. 21 CFR 182.6085 - Sodium acid phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium acid phosphate. 182.6085 Section 182.6085 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Sodium acid phosphate. (a) Product. Sodium acid phosphate. (b) Conditions of use. This substance...

  17. 1. NORTH IDAHO PHOSPHATE COMPANY PLANTS. VIEW IS TO THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. NORTH IDAHO PHOSPHATE COMPANY PLANTS. VIEW IS TO THE NORTHEAST, WITH THE SHIPPING AND STORAGE WAREHOUSE, AMMONIUM PHOSPHATE FERTILIZER PLANT, AND PHOSPHORIC ACID PLANT APPEARING IN SUCCESSION DOWN GOVERNMENT GULCH. - North Idaho Phosphate Company, Silver King Community, Kellogg, Shoshone County, ID

  18. 21 CFR 182.6085 - Sodium acid phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium acid phosphate. 182.6085 Section 182.6085 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Sodium acid phosphate. (a) Product. Sodium acid phosphate. (b) Conditions of use. This substance...

  19. 40 CFR 721.3080 - Substituted phosphate ester (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Substituted phosphate ester (generic... Substances § 721.3080 Substituted phosphate ester (generic). (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as a substituted phosphate...

  20. 40 CFR 721.3080 - Substituted phosphate ester (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Substituted phosphate ester (generic... Substances § 721.3080 Substituted phosphate ester (generic). (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as a substituted phosphate...

  1. 40 CFR 721.3080 - Substituted phosphate ester (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Substituted phosphate ester (generic... Substances § 721.3080 Substituted phosphate ester (generic). (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as a substituted phosphate...

  2. 40 CFR 721.3080 - Substituted phosphate ester (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Substituted phosphate ester (generic... Substances § 721.3080 Substituted phosphate ester (generic). (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as a substituted phosphate...

  3. 21 CFR 582.6085 - Sodium acid phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Sodium acid phosphate. 582.6085 Section 582.6085 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Sodium acid phosphate. (a) Product. Sodium acid phosphate. (b) Conditions of use. This substance...

  4. Dominant oceanic bacteria secure phosphate using a large extracellular buffer

    PubMed Central

    Zubkov, Mikhail V.; Martin, Adrian P.; Hartmann, Manuela; Grob, Carolina; Scanlan, David J.

    2015-01-01

    The ubiquitous SAR11 and Prochlorococcus bacteria manage to maintain a sufficient supply of phosphate in phosphate-poor surface waters of the North Atlantic subtropical gyre. Furthermore, it seems that their phosphate uptake may counter-intuitively be lower in more productive tropical waters, as if their cellular demand for phosphate decreases there. By flow sorting 33P-phosphate-pulsed 32P-phosphate-chased cells, we demonstrate that both Prochlorococcus and SAR11 cells exploit an extracellular buffer of labile phosphate up to 5–40 times larger than the amount of phosphate required to replicate their chromosomes. Mathematical modelling is shown to support this conclusion. The fuller the buffer the slower the cellular uptake of phosphate, to the point that in phosphate-replete tropical waters, cells can saturate their buffer and their phosphate uptake becomes marginal. Hence, buffer stocking is a generic, growth-securing adaptation for SAR11 and Prochlorococcus bacteria, which lack internal reserves to reduce their dependency on bioavailable ambient phosphate. PMID:26198420

  5. 40 CFR 436.180 - Applicability; description of the phosphate rock subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... phosphate rock subcategory. 436.180 Section 436.180 Protection of Environment ENVIRONMENTAL PROTECTION... SOURCE CATEGORY Phosphate Rock Subcategory § 436.180 Applicability; description of the phosphate rock... bearing rock, ore or earth for the phosphate content....

  6. 40 CFR 436.180 - Applicability; description of the phosphate rock subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... phosphate rock subcategory. 436.180 Section 436.180 Protection of Environment ENVIRONMENTAL PROTECTION... SOURCE CATEGORY Phosphate Rock Subcategory § 436.180 Applicability; description of the phosphate rock... bearing rock, ore or earth for the phosphate content....

  7. 40 CFR 436.180 - Applicability; description of the phosphate rock subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... phosphate rock subcategory. 436.180 Section 436.180 Protection of Environment ENVIRONMENTAL PROTECTION... SOURCE CATEGORY Phosphate Rock Subcategory § 436.180 Applicability; description of the phosphate rock... bearing rock, ore or earth for the phosphate content....

  8. 40 CFR 422.60 - Applicability; description of the sodium phosphates subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... sodium phosphates subcategory. 422.60 Section 422.60 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS PHOSPHATE MANUFACTURING POINT SOURCE CATEGORY Sodium Phosphates Subcategory § 422.60 Applicability; description of the sodium phosphates subcategory....

  9. 40 CFR 422.60 - Applicability; description of the sodium phosphates subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... sodium phosphates subcategory. 422.60 Section 422.60 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS PHOSPHATE MANUFACTURING POINT SOURCE CATEGORY Sodium Phosphates Subcategory § 422.60 Applicability; description of the sodium phosphates subcategory....

  10. Differentiating phosphate-dependent and phosphate-independent systemic phosphate-starvation response networks in Arabidopsis thaliana through the application of phosphite

    PubMed Central

    Jost, Ricarda; Pharmawati, Made; Lapis-Gaza, Hazel R.; Rossig, Claudia; Berkowitz, Oliver; Lambers, Hans; Finnegan, Patrick M.

    2015-01-01

    Phosphite is a less oxidized form of phosphorus than phosphate. Phosphite is considered to be taken up by the plant through phosphate transporters. It can mimic phosphate to some extent, but it is not metabolized into organophosphates. Phosphite could therefore interfere with phosphorus signalling networks. Typical physiological and transcriptional responses to low phosphate availability were investigated and the short-term kinetics of their reversion by phosphite, compared with phosphate, were determined in both roots and shoots of Arabidopsis thaliana. Phosphite treatment resulted in a strong growth arrest. It mimicked phosphate in causing a reduction in leaf anthocyanins and in the expression of a subset of the phosphate-starvation-responsive genes. However, the kinetics of the response were slower than for phosphate, which may be due to discrimination against phosphite by phosphate transporters PHT1;8 and PHT1;9 causing delayed shoot accumulation of phosphite. Transcripts encoding PHT1;7, lipid-remodelling enzymes such as SQD2, and phosphocholine-producing NMT3 were highly responsive to phosphite, suggesting their regulation by a direct phosphate-sensing network. Genes encoding components associated with the ‘PHO regulon’ in plants, such as At4, IPS1, and PHO1;H1, generally responded more slowly to phosphite than to phosphate, except for SPX1 in roots and MIR399d in shoots. Two uncharacterized phosphate-responsive E3 ligase genes, PUB35 and C3HC4, were also highly phosphite responsive. These results show that phosphite is a valuable tool to identify network components directly responsive to phosphate. PMID:25697796

  11. Differentiating phosphate-dependent and phosphate-independent systemic phosphate-starvation response networks in Arabidopsis thaliana through the application of phosphite.

    PubMed

    Jost, Ricarda; Pharmawati, Made; Lapis-Gaza, Hazel R; Rossig, Claudia; Berkowitz, Oliver; Lambers, Hans; Finnegan, Patrick M

    2015-05-01

    Phosphite is a less oxidized form of phosphorus than phosphate. Phosphite is considered to be taken up by the plant through phosphate transporters. It can mimic phosphate to some extent, but it is not metabolized into organophosphates. Phosphite could therefore interfere with phosphorus signalling networks. Typical physiological and transcriptional responses to low phosphate availability were investigated and the short-term kinetics of their reversion by phosphite, compared with phosphate, were determined in both roots and shoots of Arabidopsis thaliana. Phosphite treatment resulted in a strong growth arrest. It mimicked phosphate in causing a reduction in leaf anthocyanins and in the expression of a subset of the phosphate-starvation-responsive genes. However, the kinetics of the response were slower than for phosphate, which may be due to discrimination against phosphite by phosphate transporters PHT1;8 and PHT1;9 causing delayed shoot accumulation of phosphite. Transcripts encoding PHT1;7, lipid-remodelling enzymes such as SQD2, and phosphocholine-producing NMT3 were highly responsive to phosphite, suggesting their regulation by a direct phosphate-sensing network. Genes encoding components associated with the 'PHO regulon' in plants, such as At4, IPS1, and PHO1;H1, generally responded more slowly to phosphite than to phosphate, except for SPX1 in roots and MIR399d in shoots. Two uncharacterized phosphate-responsive E3 ligase genes, PUB35 and C3HC4, were also highly phosphite responsive. These results show that phosphite is a valuable tool to identify network components directly responsive to phosphate. PMID:25697796

  12. [The pentose phosphate pathway and NADP-dependent glycerol-3-phosphate dehydrogenase activity in some tissues of albino rat].

    PubMed

    Glushankov, E P; Epifanova, Iu E; Kolotilova, A I

    1976-10-01

    The NADP-dependent glycerol-3-phosphate dehydrogenase activity in liver, heart and skeletal muscle of rat was studied. The activity is found when glyceraldehyde-3-phosphate or ribose-5-phosphate in the presence of ATP are taken as substrates. The data obtained confirm that NADP-dependent glycerol-3-phosphate dehydrogenase exists in skeletal muscle and demonstrate that it is found in heart muscle as well.

  13. Biochemical genetics of the pentose phosphate cycle: human ribose 5-phosphate isomerase (RPI) and ribulose 5-phosphate 3-epimerase (RPE).

    PubMed

    Spencer, N; Hopkinson, D A

    1980-05-01

    1. Staining procedures are described for the detection after starch-gel electrophoresis of ribose-5-phosphate isomerase (RPI) and ribulose 5-phosphate 3-epimerase (RPE). 2. Both RPI and RPE were detected in all human tissues including red cells, lymphocytes and fibroblasts. 3. No evidence was found for more than one structural gene locus for either enzyme. 4. No allelic variants of either enzyme were found in erythrocyte lysates from over 200 unrelated individuals. 5. Preliminary data are presented which suggest that differences in tissue RPE isozyme patterns may be due to endogenous proteolytic activity. 6. Electrophoretic analysis of RPE and RPI isozyme patterns in extracts of man/mouse hybrid cells indicates that RPE is probably a dimer and RPI may also be polymeric.

  14. Conversion of Glucose-1-Phosphate to 3-Keto-glucose-1-phosphate by Cells of Agrobacterium tumefaciens

    PubMed Central

    Fukui, Sakuzo

    1969-01-01

    Incubation of resting cells of Agrobacterium tumefaciens with glucose-1-phosphate resulted in the accumulation of a new sugar phosphate in the suspending medium. Approximately 80% of the glucose-1-phosphate consumed was converted to the new compound, which was identified as α-d-ribo-hexopyranosyl-3-ulose-1-phosphate (3-ketoglucose-1-phosphate). Both utilization of glucose-1-phosphate and accumulation of 3-ketoglucose-1-phosphate were inhibited by 2,4-dinitrophenol, polymyxin, and d-glucose, which are inhibitors of the glucoside transport system of this bacterium but are not inhibitors of d-glucoside-3-dehydrogenase, which is the 3-ketoglucose-1-phosphate-forming enzyme. Consequently, it was concluded that glucose-1-phosphate penetrates into intracellular space by means of an active transport system. The glucose-1-phosphate is converted to 3-ketoglucose-1-phosphate by d-glucoside-3-dehydrogenase, and the 3-ketoglucose-1-phosphate formed reaches the extracellular space by passing through the surface layer of the bacterium. PMID:4304223

  15. Kinetics of phosphate absorption in lactating dairy cows after enteral administration of sodium phosphate or calcium phosphate salts.

    PubMed

    Grünberg, Walter; Dobbelaar, Paul; Breves, Gerhard

    2013-09-28

    Hypophosphataemia is frequently encountered in dairy cows during early lactation. Although supplementation of P is generally recommended, controversy exists over the suitability of oral P supplementation in animals with decreased or absent rumen motility. Since the effects of transruminal P absorption and the reticular groove reflex on the absorption kinetics of P are not well understood, it is unclear in how far treatment efficacy of oral P supplementation is affected by decreased rumen motility. Phosphate absorption was studied in six phosphate-depleted dairy cows fitted with rumen cannulas and treated with test solutions containing either NaH2PO4 or CaHPO4 with acetaminophen. Each animal was treated orally, intraruminally and intra-abomasally in randomised order. Absorption kinetics of P were studied and compared with the absorption kinetics of acetaminophen, a marker substance only absorbed from the small intestine. Intra-abomasal treatment with NaH2PO4 resulted in the most rapid and highest peaks in plasma inorganic P (Pi) concentration. Oral and intraruminal administration of NaH2PO4 resulted in similar increases in plasma Pi concentration from 4 to 7 h in both groups. Treatment with NaH2PO4 caused more pronounced peaks in plasma Pi concentration compared with CaHPO4. Neither transruminal P absorption nor the reticular groove reflex affected P absorption kinetics as determined by comparing plasma concentration–time curves of P and acetaminophen after administration of 1M-phosphate salt solutions. It is concluded that oral treatment with NaH2PO4 but not CaHPO4 is effective in supplementing P in hypophosphataemic cows with adequate rumen motility. Decreased rumen motility is likely to hamper the efficacy of oral phosphate treatment.

  16. [Iron-based Phosphate Binders for ESRD Patients].

    PubMed

    Cozzolino, Mario; Mangano, Michela; Magagnoli, Lorenza; Di Lullo, Luca; Galassi, Andrea; Brancaccio, Diego; Bellasi, Antonio

    2016-01-01

    Several factors influence the choice of phosphate binder for patients, including older age, male gender, post-menopause, diabetes, low bone turnover, vascular/valvular calcification and inflammation. Unlike calcium-based phosphate binders, non-calcium-based phosphate binders, such as sevelamer and lanthanum carbonate, have been able to reduce the progression of bone disease to adynamic bone among patients with CKD. New iron-based phosphate binders are now available. With multiple options available for the reduction of phosphate, the focus has been on agents that do not contain calcium. This is because it is thought that calcium itself functions as a substrate for calcification. PMID:27545638

  17. Determining the Origin of Phosphates in Lherzolitic Shergottites Through Phosphate Saturation Experiments

    NASA Astrophysics Data System (ADS)

    Calvin, C.; Rutherford, M.

    2007-12-01

    Phosphorous has been correlated with sulfur and chlorine in martian soils with some soils containing several wt % P2O5 and high-P2O5 layer covers many rocks. However, using the RAT to remove the top few mm of some rocks revealed zones of low-P2O5 in the outer mm relative to the interior composition. This suggests that some igneous rocks of Mars are high in P2O5 and that over time phosphorous has been mobilized into the martian soils. In martian meteorites, phosphorous has been detected in high concentrations relative to terrestrial basalts and cumulates. High intensity x-ray maps of lherzolitic shergottite ALH 77005 reveal phosphates in olivine-hosted melt inclusions and P2O5 zoning in the host-olivine. Analyses of rehomogenized olivine-hosted melt inclusions reveal high-P2O5 glasses (>5 wt %). As phosphates are the major reservoir of REE in martian meteorites, determining if the phosphates are primary igneous or secondary sedimentary minerals may have significant consequences for use of REE as oxybarometers and radiogenic-isotopic dating systems in these meteorites. Therefore, an experimental investigation was initiated to determine whether the phosphates are primary igneous minerals or secondary weathering products. The phosphate saturation curve in SNC magmatic compositions has been studied experimentally by synthesizing the parental melt composition of lherzolitic shergottite ALH 77005 and performing anhydrous crystallization experiments in TZM pressure vessels. The parental melt composition was then doped with 5 wt % P2O5 in the form of CaHPO4 and the crystallization experiments were repeated. ALH 77005's parental melt saturated phosphate near 7 wt % at 1165°C and 5 wt % at 1150°C. These saturation values illustrate how high-P2O5 would have to build up before phosphates would nucleate and are consistent with high-2O5 content found in rehomogenized olivine-hosted melt inclusions. These saturation values are higher than the reported saturation for lunar and

  18. Dual Mechanism of Ion Permeation through VDAC Revealed with Inorganic Phosphate Ions and Phosphate Metabolites

    PubMed Central

    Krammer, Eva-Maria; Vu, Giang Thi; Homblé, Fabrice; Prévost, Martine

    2015-01-01

    In the exchange of metabolites and ions between the mitochondrion and the cytosol, the voltage-dependent anion channel (VDAC) is a key element, as it forms the major transport pathway for these compounds through the mitochondrial outer membrane. Numerous experimental studies have promoted the idea that VDAC acts as a regulator of essential mitochondrial functions. In this study, using a combination of molecular dynamics simulations, free-energy calculations, and electrophysiological measurements, we investigated the transport of ions through VDAC, with a focus on phosphate ions and metabolites. We showed that selectivity of VDAC towards small anions including monovalent phosphates arises from short-lived interactions with positively charged residues scattered throughout the pore. In dramatic contrast, permeation of divalent phosphate ions and phosphate metabolites (AMP and ATP) involves binding sites along a specific translocation pathway. This permeation mechanism offers an explanation for the decrease in VDAC conductance measured in the presence of ATP or AMP at physiological salt concentration. The binding sites occur at similar locations for the divalent phosphate ions, AMP and ATP, and contain identical basic residues. ATP features a marked affinity for a central region of the pore lined by two lysines and one arginine of the N-terminal helix. This cluster of residues together with a few other basic amino acids forms a “charged brush” which facilitates the passage of the anionic metabolites through the pore. All of this reveals that VDAC controls the transport of the inorganic phosphates and phosphate metabolites studied here through two different mechanisms. PMID:25860993

  19. [Removal of Phosphate by Calcite in Open-System].

    PubMed

    Li, Zhen-xuan; Diao, Jia-yong; Huang, Li-dong; Chen, Yan-fan; Liu, Da-gang; Xu, Zheng-wen

    2015-12-01

    Batch methods were deployed to study the removal of phosphate by calcite in an open-system. Results showed that: (1) The pre-equilibrium process of calcite in open system could be achieved within 24 hours (2) The kinetic results showed that, at initial concentration of 0.5 mg · L⁻¹, the phosphate removal was almost completed within 10 hours of the first phase. The observation may be attributed to surface adsorption. At initial concentration of 2.5 mg · L⁻¹, the phosphate removal was mainly carried out by the precipitation of phosphate at later stage of the process; (3) At initial concentration of ≤ 2.5 mg · L⁻¹ setting 10 h as reaction time, the phosphate removal process was described well by the Langmuir model. It is hypothesized that surface adsorption was the principal removal way of phosphate; (4) With the addition of phthalate, at initial concentration of < 2.5 mg · L⁻¹, the phosphate removal rate experienced a small decrease. That was because phosphate was mainly removed by surface adsorption, and thus, phthalate was a competitor to phosphate for the same adsorption site. The phosphate removal rate increased a little at initial concentration of > 2.5 mg · L⁻¹, this was because the phosphate precipitation was reinforced by the increase of calcium concentration, which was caused by phthalate addition. PMID:27011989

  20. The metal-binding sites of glycose phosphates.

    PubMed

    Gilg, Kathrin; Mayer, Tobias; Ghaschghaie, Natascha; Klüfers, Peter

    2009-10-14

    In aqueous solution, the reducing sugar phosphates D-arabinose 5-phosphate, D-ribose 5-phosphate, D-fructose 1,6-bisphosphate, D-fructose 6-phosphate, D-glucose 6-phosphate and D-mannose 6-phosphate provide metal-binding sites at their glycose core on reaction with Pd(II)(en) or M(III)(tacn) residues (M = Ga, Co; en = ethylenediamine, tacn = 1,4,7-triazacyclononane). The individual species were detected by one- and two-dimensional NMR spectroscopy. The coordination patterns are related to the metal-binding modes of the respective parent glycoses. In detail, ribo- and arabinofuranose phosphate favour kappaO(1,3) coordination, whereas the ketofuranose core of fructose phosphate and fructose bisphosphate provides the kappaO(2,3) chelator thus maintaining the configuration of the respective major solution anomer. On palladium excess, D-fructose 6-phosphate is metallated twice in a unique kappaO(1,3):kappaO(2,4) metallation pattern. Dimetallation is also found for the aldohexose phosphates. A mixed glycose-core-phosphate chelation was detected for Pd(II)(en) and M(III)(tacn) residues with M = Al, Ga in the pH range just above the physiological pH for the D-fructose 1,6-bisphosphate ligand. The results are discussed in relation to D-fructose-1,6-bisphosphate-metabolism in class-II aldolases. PMID:19771356

  1. Relationship between Nitrite Reduction and Active Phosphate Uptake in the Phosphate-Accumulating Denitrifier Pseudomonas sp. Strain JR 12

    PubMed Central

    Barak, Yoram; van Rijn, Jaap

    2000-01-01

    Phosphate uptake by the phosphate-accumulating denitrifier Pseudomonas sp. JR12 was examined with different combinations of electron and carbon donors and electron acceptors. Phosphate uptake in acetate-supplemented cells took place with either oxygen or nitrate but did not take place when nitrite served as the final electron acceptor. Furthermore, nitrite reduction rates by this denitrifier were shown to be significantly reduced in the presence of phosphate. Phosphate uptake assays in the presence of the H+-ATPase inhibitor N,N′-dicyclohexylcarbodiimide (DCCD), in the presence of the uncoupler carbonyl cyanide 3-chlorophenylhydrazone (CCCP), or with osmotic shock-treated cells indicated that phosphate transport over the cytoplasmic membrane of this bacterium was mediated by primary and secondary transport systems. By examining the redox transitions of whole cells at 553 nm we found that phosphate addition caused a significant oxidation of a c-type cytochrome. Based on these findings, we propose that this c-type cytochrome serves as an intermediate in the electron transfer to both nitrite reductase and the site responsible for active phosphate transport. In previous studies with this bacterium we found that the oxidation state of this c-type cytochrome was significantly higher in acetate-supplemented, nitrite-respiring cells (incapable of phosphate uptake) than in phosphate-accumulating cells incubated with different combinations of electron donors and acceptors. Based on the latter finding and results obtained in the present study it is suggested that phosphate uptake in this bacterium is subjected to a redox control of the active phosphate transport site. By means of this mechanism an explanation is provided for the observed absence of phosphate uptake in the presence of nitrite and inhibition of nitrite reduction by phosphate in this organism. The implications of these findings regarding denitrifying, phosphate removal wastewater plants is discussed. PMID

  2. Dehydrogenation of cyclic hydrocarbons on IIIa group metal phosphates

    SciTech Connect

    Krymova, V.V.; Gryuznova, Z.V.; Yeshcenko, L.S.

    1983-01-01

    The physico-chemical properties of gallium and indium phosphates in stoichiometric proportions are evaluated for their activity in the dehydrogenation of six-membered cyclic hydrocarbons. A study was made of physical and chemical properties of stoichiometric Ga and In phosphates and their catalytic activity in dehydrogenation of six-membered cyclic hydrocarbons, these in turn were compared with A1 phosphate. The activity and selectivity of these catalysts in dehydrogenation are shown to be decisively influenced by the type of cation. Dehydrogenation of cyclic hydrocarbons on aluminium, gallium and indium phosphates takes place in stages. A tendency towards increased catalytic activity of metal phosphate is observed and indium phosphate is the most active and specific catalyst in this group of phosphates.

  3. International Strategic Minerals Inventory summary report; phosphate

    USGS Publications Warehouse

    Krauss, Ulrich H.; Saam, Henning G.; Schmidt, Helmut

    1984-01-01

    Major world resources of phosphate, a strategic mineral commodity, are described in this summary report of information in the International Strategic Minerals Inventory {ISMI}. ISMI is a cooperative data-collection effort of earth-science and mineral-resource agencies in Australia, Canada, the Federal Republic of Germany, the Republic of South Africa, and the United States of America. This report, designed to be of benefit to policy analysts, contains two parts. Part I presents an overview of the resources and potential supply of phosphate on the basis of inventory information. Part II contains tables of some of the geologic information and mineral-resource and production data that were collected by ISMI participants.

  4. Aluminum phosphate ceramics for waste storage

    SciTech Connect

    Wagh, Arun; Maloney, Martin D

    2014-06-03

    The present disclosure describes solid waste forms and methods of processing waste. In one particular implementation, the invention provides a method of processing waste that may be particularly suitable for processing hazardous waste. In this method, a waste component is combined with an aluminum oxide and an acidic phosphate component in a slurry. A molar ratio of aluminum to phosphorus in the slurry is greater than one. Water in the slurry may be evaporated while mixing the slurry at a temperature of about 140-200.degree. C. The mixed slurry may be allowed to cure into a solid waste form. This solid waste form includes an anhydrous aluminum phosphate with at least a residual portion of the waste component bound therein.

  5. [Novel phosphate regulating genes and osteoporosis].

    PubMed

    Miyamoto, Kenichi; Ito, Mikiko; Segawa, Hiroko

    2005-05-01

    The hormones currently believe to influence inorganic phosphate (Pi) metabolism are parathyroid hormone (PTH) and the active metabolite to vitamin D. A new class of phosphate-regulating factors, collectively known as the phosphatonins have been shown to be associated with the hypophosphatemic diseases. The reabsorption of Pi in the kidney is a major determinant of the plasma Pi level. Reabsorption is largely regulated by the type II a sodium-dependent Pi cotransporter (NPT2a) that is expressed in renal proximal tubular cells. Phosphatonins cause Pi wasting by controlling the amount of NPT2a on the apical surface of the proximal tubular cell. A recent finding indicates that mutations in NPT2a can contribute to nephrolithiasis and osteoporosis in humans and suggests that changes in NPT2a levels may also cause other human disease. We discuss the roles of phosphatonins and NPT2a in bone formation. PMID:15876740

  6. Biomedical monitoring of phosphate removal by hemodialysis.

    PubMed

    Michalec, Michał; Fiedoruk-Pogrebniak, Marta; Matuszkiewicz-Rowińska, Joanna; Tymecki, Łukasz; Koncki, Robert

    2016-07-15

    A compact flow analysis system for non-invasive, dialysate-side monitoring of phosphate removal in the course of clinical hemodialysis treatment is presented. The monitor is based on solenoid operated micro-pumps and extremely cheap optoelectronic flow-through detector allowing photometric determination of phosphate in spent dialysate using a molybdenum blue method. The monitor can operate in both, discrete and continuous modes of measurement. The analytical utility of monitor has been tested with samples of spent dialysate produced by artificial kidney in the course of real hemodialysis sessions. The results of monitoring are comparable with those obtained using reference off-line method recommended for clinical analysis. Additionally, the possibility of two-side (dialysate and blood) monitoring of hemodialysis treatments with optoelectronic flow-through detectors has been announced. PMID:27136282

  7. Phosphate Barriers for Immobilization of Uranium Plumes

    SciTech Connect

    Burns, Peter C.

    2005-06-01

    Uranium contamination of the subsurface has remained a persistent problem plaguing remedial design at sites across the U.S. that were involved with production, handling, storage, milling, and reprocessing of fissile uranium for both civilian and defense related purposes. Remediation efforts to date have relied upon excavation, pump-and-treat, or passive remediation barriers (PRB?s) to remove or attenuate uranium mobility. Documented cases convincingly demonstrate that excavation and pump-and-treat methods are ineffective for a number of highly contaminated sites. There is growing concern that use of conventional PRB?s, such as zero-valent iron, are a temporary solution to a problem that will persist for thousands of years. Alternatives to the standard treatment methods are therefore warranted. The core objective of our research is to demonstrate that a phosphorous amendment strategy will result in a reduction of dissolved uranium to below the proposed drinking water standard. Our hypothesis is that long-chain polyphosphate compounds forestall precipitation of sparingly soluble uranyl phosphate compounds, which is key to preventing fouling of wells at the point of injection. Our other fundamental objective is to synthesize and correctly characterize the uranyl phosphate phases that form in the geochemical conditions under consideration. This report summarizes work conducted at the University of Notre Dame through November of 2003 under DOE grant DE-FG07-02ER63489, which has been funded since September, 2002. The objectives at Notre Dame are development of synthesis techniques for uranyl phosphate phases, together with detailed structural and chemical characterization of the myriad of uranyl phosphate phases that may form under geochemical conditions under consideration.

  8. Phosphate Barriers for Immobilization of Uranium Plumes

    SciTech Connect

    Burns, Peter C.

    2005-06-01

    Uranium contamination of the subsurface has remained a persistent problem plaguing remedial design at sites across the U.S. that were involved with production, handling, storage, milling, and reprocessing of fissile uranium for both civilian and defense related purposes. Remediation efforts to date have relied upon excavation, pump-and-treat, or passive remediation barriers (PRB's) to remove or attenuate uranium mobility. Documented cases convincingly demonstrate that excavation and pump-and-treat methods are ineffective for a number of highly contaminated sites. There is growing concern that use of conventional PRB?s, such as zero-valent iron, are a temporary solution to a problem that will persist for thousands of years. Alternatives to the standard treatment methods are therefore warranted. The core objective of our research is to demonstrate that a phosphorus amendment strategy will result in a reduction of dissolved uranium to below the proposed drinking water standard. Our hypothesis is that long-chain polyphosphate compounds forestall precipitation of sparingly soluble uranyl phosphate compounds, which is key to preventing fouling of wells at the point of injection. Our other fundamental objective is to synthesize and correctly characterize the uranyl phosphate phases that form in the geochemical conditions under consideration. This report summarizes work conducted at the University of Notre Dame through November of 2003 under DOE grant DE-FG07-02ER63489, which has been funded since September, 2002. The objectives at Notre Dame are development of synthesis techniques for uranyl phosphate phases, together with detailed structural and chemical characterization of the myriad of uranyl phosphate phases that may form under geochemical conditions under consideration.

  9. Phosphate Bonded Solidification of Radioactive Incinerator Wastes

    SciTech Connect

    Walker, B. W.

    1999-04-13

    The incinerator at the Department of Energy Savannah River Site burns low level radioactive and hazardous waste. Ash and scrubber system waste streams are generated during the incineration process. Phosphate Ceramic technology is being tested to verify the ash and scrubber waste streams can be stabilized using this solidification method. Acceptance criteria for the solid waste forms include leachability, bleed water, compression testing, and permeability. Other testing on the waste forms include x-ray diffraction and scanning electron microscopy.

  10. Fourier transform Raman spectroscopy of synthetic and biological calcium phosphates.

    PubMed

    Sauer, G R; Zunic, W B; Durig, J R; Wuthier, R E

    1994-05-01

    Fourier-transform (FT) Raman spectroscopy was used to characterize the organic and mineral components of biological and synthetic calcium phosphate minerals. Raman spectroscopy provides information on biological minerals that is complimentary to more widely used infrared methodologies as some infrared-inactive vibrational modes are Raman-active. The application of FT-Raman technology has, for the first time, enabled the problems of high sample fluorescence and low signal-to-noise that are inherent in calcified tissues to be overcome. Raman spectra of calcium phosphates are dominated by a very strong band near 960 cm-1 that arises from the symmetric stretching mode (v1) of the phosphate group. Other Raman-active phosphate vibrational bands are seen at approximately 1075 (v3), 590 (v4), and 435 cm-1 (v2). Minerals containing acidic phosphate groups show additional vibrational modes. The different calcium phosphate mineral phases can be distinguished from one another by the relative positions and shapes of these bands in the Raman spectra. FT-Raman spectra of nascent, nonmineralized matrix vesicles (MV) show a distinct absence of the phosphate v1 band even though these structures are rich in calcium and phosphate. Similar results were seen with milk casein and synthetic Ca-phosphatidyl-serine-PO4 complexes. Hence, the phosphate and/or acidic phosphate ions in these noncrystalline biological calcium phosphates is in a molecular environment that differs from that in synthetic amorphous calcium phosphate. In MV, the first distinct mineral phase to form contained acidic phosphate bands similar to those seen in octacalcium phosphate. The mineral phase present in fully mineralized MV was much more apatitic, resembling that found in bones and teeth.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Nano-porous calcium phosphate balls.

    PubMed

    Kovach, Ildyko; Kosmella, Sabine; Prietzel, Claudia; Bagdahn, Christian; Koetz, Joachim

    2015-08-01

    By dropping a NaH2PO4·H2O precursor solution to a CaCl2 solution at 90°C under continuous stirring in presence of two biopolymers, i.e. gelatin (G) and chitosan (C), supramolecular calcium phosphate (CP) card house structures are formed. Light microscopic investigations in combination with scanning electron microscopy show that the GC-based flower-like structure is constructed from very thin CP platelets. Titration experiments indicate that H-bonding between both biopolymers is responsible for the synergistic effect in presence of both polymers. Gelatin-chitosan-water complexes play an important role with regard to supramolecular ordering. FTIR spectra in combination with powder X-ray diffraction show that after burning off all organic components (heating up >600°C) dicalcium and tricalcium phosphate crystallites are formed. From high resolution transmission electron microscopy (HR-TEM) it is obvious to conclude, that individual crystal platelets are dicalcium phosphates, which build up ball-like supramolecular structures. The results reveal that the GC guided crystal growth leads to nano-porous supramolecular structures, potentially attractive candidates for bone repair. PMID:26052107

  12. Phosphine from rocks: mechanically driven phosphate reduction?

    PubMed

    Glindemann, Dietmar; Edwards, Marc; Morgenstern, Peter

    2005-11-01

    Natural rock and mineral samples released trace amounts of phosphine during dissolution in mineral acid. An order of magnitude more phosphine (average 1982 ng PH3 kg rock and maximum 6673 ng PH3/kg rock) is released from pulverized rock samples (basalt, gneiss, granite, clay, quartzitic pebbles, or marble). Phosphine was correlated to hardness and mechanical pulverization energy of the rocks. The yield of PH3 ranged from 0 to 0.01% of the total P content of the dissolved rock. Strong circumstantial evidence was gathered for reduction of phosphate in the rock via mechanochemical or "tribochemical" weathering at quartz and calcite/marble inclusions. Artificial reproduction of this mechanism by rubbing quartz rods coated with apatite-phosphate to the point of visible triboluminescence, led to detection of more than 70 000 ng/kg PH3 in the apatite. This reaction pathway may be considered a mechano-chemical analogue of phosphate reduction from lightning or electrical discharges and may contribute to phosphine production via tectonic forces and processing of rocks.

  13. Method for phosphate-accelerated bioremediation

    DOEpatents

    Looney, Brian B.; Lombard, Kenneth H.; Hazen, Terry C.; Pfiffner, Susan M.; Phelps, Tommy J.; Borthen, James W.

    1996-01-01

    An apparatus and method for supplying a vapor-phase nutrient to contaminated soil for in situ bioremediation. The apparatus includes a housing adapted for containing a quantity of the liquid nutrient, a conduit in fluid communication with the interior of the housing, means for causing a gas to flow through the conduit, and means for contacting the gas with the liquid so that a portion thereof evaporates and mixes with the gas. The mixture of gas and nutrient vapor is delivered to the contaminated site via a system of injection and extraction wells configured to the site. The mixture has a partial pressure of vaporized nutrient that is no greater than the vapor pressure of the liquid. If desired, the nutrient and/or the gas may be heated to increase the vapor pressure and the nutrient concentration of the mixture. Preferably, the nutrient is a volatile, substantially nontoxic and nonflammable organic phosphate that is a liquid at environmental temperatures, such as triethyl phosphate or tributyl phosphate.

  14. Phosphate adsorption on lanthanum loaded biochar.

    PubMed

    Wang, Zhanghong; Shen, Dekui; Shen, Fei; Li, Tianyu

    2016-05-01

    To attain a low-cost and high-efficient phosphate adsorbent, lanthanum (La) loaded biochar (La-BC) prepared by a chemical precipitation method was developed. La-BC and its pristine biochar (CK-BC) were comparatively characterized using zeta potential, BET surface area, scanning electron microscopy/energy dispersive spectrometer (SEM-EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). The adsorption ability and the mechanisms during adsorption process for the La-BC samples were also investigated. La loaded on the surface of biochar can be termed as La-composites (such as LaOOH, LaONO3 and La(OH)3), leading to the decrease of negative charge and surface area of biochar. La-BC exhibited the high adsorption capacity to phosphate compared to CK-BC. Adsorption isotherm and adsorption kinetic studies showed that the Langmuir isotherm and second order model could well describe the adsorption process of La-BC, indicating that the adsorption was dominated by a homogeneous and chemical process. The calculated maximum adsorption capacity was as high as 46.37 mg g(-1) (computed in P). Thermodynamic analysis revealed that the adsorption was spontaneous and endothermic. SEM, XRD, XPS and FT-IR analysis suggested that the multi-adsorption mechanisms including precipitation, ligand exchange and complexation interactions can be evidenced during the phosphate adsorption process by La-composites in La-BC. PMID:26871732

  15. Nano-porous calcium phosphate balls.

    PubMed

    Kovach, Ildyko; Kosmella, Sabine; Prietzel, Claudia; Bagdahn, Christian; Koetz, Joachim

    2015-08-01

    By dropping a NaH2PO4·H2O precursor solution to a CaCl2 solution at 90°C under continuous stirring in presence of two biopolymers, i.e. gelatin (G) and chitosan (C), supramolecular calcium phosphate (CP) card house structures are formed. Light microscopic investigations in combination with scanning electron microscopy show that the GC-based flower-like structure is constructed from very thin CP platelets. Titration experiments indicate that H-bonding between both biopolymers is responsible for the synergistic effect in presence of both polymers. Gelatin-chitosan-water complexes play an important role with regard to supramolecular ordering. FTIR spectra in combination with powder X-ray diffraction show that after burning off all organic components (heating up >600°C) dicalcium and tricalcium phosphate crystallites are formed. From high resolution transmission electron microscopy (HR-TEM) it is obvious to conclude, that individual crystal platelets are dicalcium phosphates, which build up ball-like supramolecular structures. The results reveal that the GC guided crystal growth leads to nano-porous supramolecular structures, potentially attractive candidates for bone repair.

  16. Apatite Formation from Amorphous Calcium Phosphate and Mixed Amorphous Calcium Phosphate/Amorphous Calcium Carbonate.

    PubMed

    Ibsen, Casper J S; Chernyshov, Dmitry; Birkedal, Henrik

    2016-08-22

    Crystallization from amorphous phases is an emerging pathway for making advanced materials. Biology has made use of amorphous precursor phases for eons and used them to produce structures with remarkable properties. Herein, we show how the design of the amorphous phase greatly influences the nanocrystals formed therefrom. We investigate the transformation of mixed amorphous calcium phosphate/amorphous calcium carbonate phases into bone-like nanocrystalline apatite using in situ synchrotron X-ray diffraction and IR spectroscopy. The speciation of phosphate was controlled by pH to favor HPO4 (2-) . In a carbonate free system, the reaction produces anisotropic apatite crystallites with large aspect ratios. The first formed crystallites are highly calcium deficient and hydrogen phosphate rich, consistent with thin octacalcium phosphate (OCP)-like needles. During growth, the crystallites become increasingly stoichiometric, which indicates that the crystallites grow through addition of near-stoichiometric apatite to the OCP-like initial crystals through a process that involves either crystallite fusion/aggregation or Ostwald ripening. The mixed amorphous phases were found to be more stable against phase transformations, hence, the crystallization was inhibited. The resulting crystallites were smaller and less anisotropic. This is rationalized by the idea that a local phosphate-depletion zone formed around the growing crystal until it was surrounded by amorphous calcium carbonate, which stopped the crystallization. PMID:27460160

  17. Biostimulation by Glycerol Phosphate to Precipitate Recalcitrant Uranium(IV) Phosphate.

    PubMed

    Newsome, Laura; Morris, Katherine; Trivedi, Divyesh; Bewsher, Alastair; Lloyd, Jonathan R

    2015-09-15

    Stimulating the microbial reduction of aqueous uranium(VI) to insoluble U(IV) via electron donor addition has been proposed as a strategy to remediate uranium-contaminated groundwater in situ. However, concerns have been raised regarding the longevity of microbially precipitated U(IV) in the subsurface, particularly given that it may become remobilized if the conditions change to become oxidizing. An alternative mechanism is to stimulate the precipitation of poorly soluble uranium phosphates via the addition of an organophosphate and promote the development of reducing conditions. Here, we selected a sediment sample from a U.K. nuclear site and stimulated the microbial community with glycerol phosphate under anaerobic conditions to assess whether uranium phosphate precipitation was a viable bioremediation strategy. Results showed that U(VI) was rapidly removed from solution and precipitated as a reduced crystalline U(IV) phosphate mineral similar to ningyoite. This mineral was considerably more recalcitrant to oxidative remobilization than the products of microbial U(VI) reduction. Bacteria closely related to Pelosinus species may have played a key role in uranium removal in these experiments. This work has implications for the stewardship of uranium-contaminated groundwater, with the formation of U(IV) phosphates potentially offering a more effective strategy for maintaining low concentrations of uranium in groundwater over long time periods. PMID:26292021

  18. Concomitant rock phosphate dissolution and lead immobilization by phosphate solubilizing bacteria (Enterobacter sp.).

    PubMed

    Park, Jin Hee; Bolan, Nanthi; Megharaj, Mallavarapu; Naidu, Ravi

    2011-04-01

    This paper examines the potential value of phosphate solubilizing bacteria (Enterobacter cloacae) in the dissolution of rock phosphate (RP) and subsequent immobilization of lead (Pb) in both bacterial growth medium and soils. Enterobacter sp. showed resistance to Pb and the bacterium solubilized 17.5% of RP in the growth medium. Enterobacter sp. did not enhance Pb immobilization in solution because of acidification of bacterial medium, thereby inhibiting the formation of P-induced Pb precipitation. However, in the case of soil, Enterobacter sp. increased Pb immobilization by 6.98, 25.6 and 32.0% with the RP level of 200, 800 and 1600 mg P/kg, respectively. The immobilization of Pb in Pb-spiked soils was attributed to pyromorphite formation as indicated by XRD analysis. Inoculation of phosphate solubilizing bacteria with RP in soil can be used as an alternative technique to soluble P compounds which can cause eutrophication of surface water.

  19. Research and engineering assessment of biological solubilization of phosphate

    SciTech Connect

    Rogers, R.D.; McIlwain, M.E.; Losinski, S.J.; Taylor, D.D.

    1993-03-01

    This research and engineering assessment examined a microbial phosphate solubilization process as a method of recovering phosphate from phosphorus containing ore compared to the existing wet acid and electric arc methods. A total of 860 microbial isolates, collected from a range of natural environments were tested for their ability to solubilize phosphate from rock phosphate. A bacterium (Pseudomonas cepacia) was selected for extensive characterization and evaluation of the mechanism of phosphate solubilization and of process engineering parameters necessary to recover phosphate from rock phosphate. These studies found that concentration of hydrogen ion and production of organic acids arising from oxidation of the carbon source facilitated microbial solubilization of both pure chemical insoluble phosphate compounds and phosphate rock. Genetic studies found that phosphate solubilization was linked to an enzyme system (glucose dehydrogenase). Process-related studies found that a critical solids density of 1% by weight (ore to liquid) was necessary for optimal solubilization. An engineering analysis evaluated the cost and energy requirements for a 2 million ton per year sized plant, whose size was selected to be comparable to existing wet acid plants.

  20. Phosphate sources and their suitability for remediation of contaminated soils.

    PubMed

    Knox, A S; Kaplan, D I; Paller, M H

    2006-03-15

    Phosphate minerals and specifically apatite show promise for environmental cleanup because they can form stable compounds with a wide range of cationic contaminants. However, phosphate minerals naturally accumulate some heavy metals that may cause additional contamination of the environment if used improperly. Nine commercially available phosphate materials were evaluated for remediation of contaminated soil based on solubility, concentration of metal/metalloid impurities, and leachability of impurity metal/metalloids. The phosphate materials consisted of three groups: processed (i.e., fertilizers), mined (rock phosphates from different formations), and biogenic (ground fish bone). Processed and mined rock phosphates contained relatively high total concentrations of As, Co, Cr, and Cu but did not exceed the RCRA toxicity characteristic leaching procedure (TCLP) limits. Biogenic apatite contained much lower metal concentrations than processed and mined rock phosphate and was appreciably more soluble. By combining biogenic and mined phosphate it is possible to obtain a wide range of phosphate release rates, permitting rapid immobilization of contaminants while providing a slow release of phosphate for continued long-term treatment.

  1. Strong adsorption of phosphate by amorphous zirconium oxide nanoparticles.

    PubMed

    Su, Yu; Cui, Hang; Li, Qi; Gao, Shian; Shang, Jian Ku

    2013-09-15

    Phosphate removal is important in the control of eutrophication of water bodies. Adsorption is one of the promising approaches for the removal of phosphate, which could serve as a supplement for the biological phosphate removal process commonly used in the wastewater treatment industry to meet the discharge requirement when the biological performance is deteriorated from changes of operation conditions. Amorphous zirconium oxide nanoparticles were synthesized by a simple and low-cost hydrothermal process, and their phosphate removal performance was explored in aqueous environment under various conditions. A fast adsorption of phosphate was observed in the kinetics study, and their adsorption capacity was determined at about 99.01 mg/g at pH 6.2 in the equilibrium adsorption isotherm study. Commonly coexisting anions showed no or minimum effect on their phosphate adsorption performance. The phosphate adsorption showed little pH dependence in the range from pH 2 to 6, while it decreased sharply with the pH increase above pH 7. After adsorption, phosphate on these am-ZrO2 nanoparticles could be easily desorbed by NaOH solution washing. Both the macroscopic and microscopic techniques demonstrated that the phosphate adsorption mechanism of am-ZrO2 nanoparticles followed the inner-sphere complexing mechanism, and the surface hydroxyl groups played a key role in the phosphate adsorption.

  2. The aluminum phosphate zone in the Peace River area, land-pebble phosphate field, Florida

    USGS Publications Warehouse

    Cathcart, James B.

    1953-01-01

    The Peace River area, comprising T. 30 and 31 S., R. 24 and 25 E., contains a thicker and more persistent aluminum phosphate zone, and one that is higher in P2O5 and uranium content than is known elsewhere in the land-pebble phosphate district. This report has been prepared to bring together all of the information on the aluminum phosphate zone in the area where the first plant to treat this material will probably be located. The area may be divided into three physiographic units, (1) the ridge, (2) the flatwoods, and (3) the valley. Maps showing distribution and grade of the aluminum phosphate zone indicate that the zone is thin or absent in the ridge unit, thickest and most persistent, and of the best grade in P2O5 and uranium in the flatwoods unit, and absent or very low in grade in the valley unit. Maps of thickness and of chemical composition show that even in favorable areas there are places where the aluminum phosphate zone is missing or of questionable economic importance. The distribution maps also show that areas of high P2O5 and high uranium content coincide closely. Areas containing thick aluminum phosphate material usually have high uranium and P2O5 contents. It is estimated that an average of 13,000 tons per day of aluminum phosphate material might be mined from this area. This figure is based on the probable amount of time, per year, that mining would be in favorable ground. When all mines in the area are in favorable ground, the tonnage per day might be about 23,000 tons. Tonnages of aluminum phosphate material have been computed for about 36 percent of the area of T. 30 S., R. 25 E., and for 18 percent of the area of T. 31 S., R. 25 E. The total inferred tonnage is about 150,000,000 short tons, with an average grade of 0.012 percent U3O8.

  3. Using oxygen isotopes of phosphate to investigate phosphate release from sediments and phosphate input from waste water treatment plants into Lake Erie

    NASA Astrophysics Data System (ADS)

    Roberts, K.; Klass, T.; Watson, S.; Mah, B.; Paytan, A.

    2010-12-01

    Phosphorus is often a limiting nutrient in freshwater systems; however increased inputs have been promoting eutrophication in many of these systems. Phosphate is one of the more bio-available forms of phosphate and it has been suggested by Elsbury et al., (2009) that in addition to riverin input some other yet unidentified phosphate source contributes to the phosphorous loading in Lake Erie. We are using the oxygen isotope of phosphate to identify two potential sources of phosphorus into Lake Erie. Specifically we determine the isotopic composition of oxygen in phosphate which is associated with various sedimentary phases at two sites in Lake Erie. The distinct sedimentary phases have different phosphate mobility and thus release potential to the lake. In addition we determine the isotopic signature of phosphate that is released into the lake from treated waste water effluent throughout the year. Results will be compared to the isotopic signature of phosphate in Lake water to evaluate the potential contribution form each of these sources.

  4. Deposition of calcium phosphate coatings using condensed phosphates (P2O7(4-) and P3O10(5-)) as phosphate source through induction heating.

    PubMed

    Zhou, Huan; Hou, Saisai; Zhang, Mingjie; Yang, Mengmeng; Deng, Linhong; Xiong, Xinbo; Ni, Xinye

    2016-12-01

    In present work condensed phosphates (P2O7(4-) and P3O10(5-)) were used as phosphate source in induction heating to deposit calcium phosphate coatings. The phase, morphology, and composition of different phosphate-related coatings were characterized and compared using XRD, FTIR, and SEM analyses. Results showed that P2O7(4-)formed calcium pyrophosphate hydrate coatings with interconnected cuboid-like particles. The as-deposited calcium tripolyphosphate hydrate coating with P3O10(5-) was mainly composed of flower-like particles assembled by plate-like crystals. The bioactivity and cytocompatibility of the coatings were also studied. Moreover, the feasibility of using hybrid phosphate sources for preparing and depositing coatings onto magnesium alloy was investigated. PMID:27612721

  5. Integrated assessment of the phosphate industry. [Radiological impact of uranium extraction

    SciTech Connect

    Ryan, M.T.; Cotter, S.J.

    1980-05-01

    The phosphate industry in the United States includes three major activities, namely, mining and milling of phosphate rock, phosphate product manufacture, and phosphate product use. Phosphatic materials contain uranium, thorium, and their decay products in greater than background amounts. This assessment of the radiological impacts associated with the redistribution of radioactive components of phosphate materials may provide insight into the effects of uranium extraction from phosphate materials for use in the nuclear fuel cycle.

  6. Carbon Mineralization Using Phosphate and Silicate Ions

    NASA Astrophysics Data System (ADS)

    Gokturk, H.

    2013-12-01

    Carbon dioxide (CO2) reduction from combustion of fossil fuels has become an urgent concern for the society due to marked increase in weather related natural disasters and other negative consequences of global warming. CO2 is a highly stable molecule which does not readily interact with other neutral molecules. However it is more responsive to ions due to charge versus quadrupole interaction [1-2]. Ions can be created by dissolving a salt in water and then aerosolizing the solution. This approach gives CO2 molecules a chance to interact with the hydrated salt ions over the large surface area of the aerosol. Ion containing aerosols exist in nature, an example being sea spray particles generated by breaking waves. Such particles contain singly and doubly charged salt ions including Na+, Cl-, Mg++ and SO4--. Depending on the proximity of CO2 to the ion, interaction energy can be significantly higher than the thermal energy of the aerosol. For example, an interaction energy of 0.6 eV is obtained with the sulfate (SO4--) ion when CO2 is the nearest neighbor [2]. In this research interaction between CO2 and ions which carry higher charges are investigated. The molecules selected for the study are triply charged phosphate (PO4---) ions and quadruply charged silicate (SiO4----) ions. Examples of salts which contain such molecules are potassium phosphate (K3PO4) and sodium orthosilicate (Na4SiO4). The research has been carried out with first principle quantum mechanical calculations using the Density Functional Theory method with B3LYP functional and Pople type basis sets augmented with polarization and diffuse functions. Atomic models consist of the selected ions surrounded by water and CO2 molecules. Similar to the results obtained with singly and doubly charged ions [1-2], phosphate and silicate ions attract CO2 molecules. Energy of interaction between the ion and CO2 is 1.6 eV for the phosphate ion and 3.3 eV for the silicate ion. Hence one can expect that the selected

  7. Plant tissue hybrid electrode for determination of phosphate and fluoride

    SciTech Connect

    Schubert, F.; Renneberg, R.; Scheller, F.W.; Kirstein, L.

    1984-08-01

    A biosensor for inorganic phosphate and fluoride has been developed by coupling a potato (Solanum tuberosum) tissue slice and immobilized glucose oxidase with a Clark oxygen electrode. Measurement is based on the inhibition by either ion of potato acid phosphates catalyzed glucose 6-phosphate hydrolysis. The precision is 1.7% and 6.5% and the lower detection limit 2.5 X 10/sup -5/ M and 1 X 10/sup -4/ M for phosphate and fluoride, respectively. For phosphate determination the hybrid sensor is stable for 28 days or 300 assays. With a higher limit of detection the sensor can be applied in a commercial enzyme electrode based device. Its application for phosphate determination in fertilizer and urine samples is described.

  8. [Bone and tooth in calcium and phosphate metabolism].

    PubMed

    Tamamura, Yoshihiro; Yamaguchi, Akira

    2012-01-01

    Tight regulation of serum concentrations of calcium and phosphate is indispensable for maintaining normal physiological condition. Imbalance of this regulation leads to pathophysiological disorders including heart disease, chronic kidney disease, and ectopic calcification. Formation and mineralization of bone and tooth are greatly influenced by calcium and phosphate metabolism since both organs are mainly consist of calcium-phosphate. Calcium and phosphate homeostasis is under hormonal control on its target organs such as kidney, bone and intestine. Calcium and phosphate are absorbed in intestine and reabsorbed and excreted in kidney. Bone store and release them in response to changing physiological demand by osteoblastic bone formation and osteoclastic bone resorption. Bone is also important as an endocrine organ that releases FGF23 from osteocytes, a novel hormone that targets the kidney to inhibit phosphate reabsorption and 1α, 25 (OH) (2)D(3) production. PMID:22201094

  9. Weld solidification and HAZ liquation in a metastable-beta titanium alloy-Beta-21S. [Ti-15wt%Mo-2. 7wt%Nb-3wt%Al-0. 2wt%Si

    SciTech Connect

    Baeslack, W.A. III; Liu, P.S. ); Paskell, T. )

    1993-03-01

    Beta-21S is a new, metastable-beta titanium alloy which exhibits excellent oxidation resistance and mechanical properties at elevated temperatures. From a weld solidification standpoint, this alloy chemistry is of particular interest because its major beta-stabilizing elements (Mo and Nb) both exhibit equilibrium partitioning ratios (k[sub o]) greater than unity, indicating their simultaneous partitioning during weld solidification to the initial solid to form (i.e., dendrite cores), and correspondingly their depletion in the final regions of solidification (i.e., dendrite interstices). Such elemental partitioning, if retained down to room temperature, may be expected to promote local variations in the postweld aging response. The objectives of the present investigation were to characterize Gas Tungsten-Arc weld solidification and HAZ liquation phenomena in Beta-21S and to examine the influence of residual microsegregation in the weld zone on alpha precipitation during postweld heat treatment.

  10. Characterisation of Erbium Doped Phosphate Glass

    NASA Astrophysics Data System (ADS)

    Rasid, A. A.; Rohani, M. S.; Sahar, M. R.; Kasim, A.

    2010-03-01

    A series of erbium doped phosphate glass has been successfully fabricated, and the determination of their density and luminescence properties has been carried out. It is particularly interesting to study the effect of modifying oxides to the properties of the glass. The glass density reduces with the increasing content of Na2O. The emission spectra from luminescence spectroscopy resolved six emission peaks from the excitation wavelength of 336.8 nm (3.69 eV). The emission of 4F7/2 gives two emission peaks, where the peak near 482 nm shows a higher intensity and the peak near 491 nm gives a weak emission spectra.

  11. Novel lead-iron phosphate glass

    DOEpatents

    Boatner, Lynn A.; Sales, Brian C.

    1989-01-01

    The invention described and claimed in the specification relates to the discovery that effective addition of Fe.sub.2 O.sub.3 to a lead phosphate glass results in a glass having enhanced chemical durability and physical stability, and consists essentially of the glass resulting from melting a mixture consisting essentially of, in weight percent, 40-66 percent PbO, 30-55 percent P.sub.2 O.sub.5 and an effective concentration up to 12 percent Fe.sub.2 O.sub.3.

  12. Growth Layers on Ammonium Dihydrogen Phosphate.

    PubMed

    Torgesen, J L; Jackson, R W

    1965-05-14

    Microscopic observations of growth layers and etch pits on ammonium dihydrogen phosphate crystals reveal screw dislocations on the {100} face generating elliptical spirals that change rapidly but reversibly to rectangular shape when chromium-ion impurity is added. The effects of the impurity on crystal habit are judged to be secondary to changes in the morphology of the growth layers. No sources of growth are observed on the {101} faces; the layers spread inward from the edges and at times are mutually annihilating so that, temporarily, no steps are observed. Similar behavior is recorded for the {1011} faces of NaNO(3).

  13. The pentose phosphate pathway and cancer.

    PubMed

    Patra, Krushna C; Hay, Nissim

    2014-08-01

    The pentose phosphate pathway (PPP), which branches from glycolysis at the first committed step of glucose metabolism, is required for the synthesis of ribonucleotides and is a major source of NADPH. NADPH is required for and consumed during fatty acid synthesis and the scavenging of reactive oxygen species (ROS). Therefore, the PPP plays a pivotal role in helping glycolytic cancer cells to meet their anabolic demands and combat oxidative stress. Recently, several neoplastic lesions were shown to have evolved to facilitate the flux of glucose into the PPP. This review summarizes the fundamental functions of the PPP, its regulation in cancer cells, and its importance in cancer cell metabolism and survival.

  14. Intercalation of cyclic ketones into vanadyl phosphate

    SciTech Connect

    Zima, Vitezslav . E-mail: vitezslav.zima@upce.cz; Melanova, Klara; Benes, Ludvik; Trchova, Miroslava; Dybal, Jiri

    2005-01-15

    Intercalation compounds of vanadyl phosphate with cyclic ketones (cyclopentanone, cyclohexanone, 4-methylcyclohexanone, and 1,4-cyclohexanedione) were prepared from corresponding propanol or ethanol intercalates by a molecular exchange. The intercalates prepared were characterized using powder X-ray diffraction and thermogravimetric analysis. The intercalates are stable in dry environment and decompose slowly in humid air. Infrared and Raman spectra indicate that carbonyl oxygens of the guest molecules are coordinated to the vanadium atoms of the host layers. The local structure and interactions in the cyclopentanone intercalate have been suggested on the basis of quantum chemical calculations.

  15. Novel lead-iron phosphate glass

    DOEpatents

    Boatner, L.A.; Sales, B.C.

    1989-07-11

    The invention described and claimed in the specification relates to the discovery that effective addition of Fe[sub 2]O[sub 3] to a lead phosphate glass results in a glass having enhanced chemical durability and physical stability, and consists essentially of the glass resulting from melting a mixture consisting essentially of, in weight percent, 40--66 percent PbO, 30--55 percent P[sub 2]O[sub 5] and an effective concentration up to 12 percent Fe[sub 2]O[sub 3].

  16. Regulation of Phosphate Accumulation in the Unicellular Cyanobacterium Synechococcus

    PubMed Central

    Grillo, John F.; Gibson, Jane

    1979-01-01

    The phosphorus contents of acid-soluble pools, lipid, ribonucleic acid, and acid-insoluble polyphosphate were lowered in Synechococcus in proportion to the reduction in growth rate in phosphate-limited but not in nitrate-limited continuous culture. Phosphorus in these cell fractions was lost proportionately during progressive phosphate starvation of batch cultures. Acid-insoluble polyphosphate was always present in all cultural conditions to about 10% of total cell phosphorus and did not turn over during balanced exponential growth. Extensive polyphosphate formation occurred transiently when phosphate was given to cells which had been phosphate limited. This material was broken down after 8 h even in the presence of excess external orthophosphate, and its phosphorus was transferred into other cell fractions, notably ribonucleic acid. Phosphate uptake kinetics indicated an invariant apparent Km of about 0.5 μM, but Vmax was 40 to 50 times greater in cells from phosphate-limited cultures than in cells from nitrate-limited or balanced batch cultures. Over 90% of the phosphate taken up within the first 30 s at 15°C was recovered as orthophosphate. The uptake process is highly specific, since neither phosphate entry nor growth was affected by a 100-fold excess of arsenate. The activity of polyphosphate synthetase in cell extracts increased at least 20-fold during phosphate starvation or in phosphate-restricted growth, but polyphosphatase activity was little changed by different growth conditions. The findings suggest that derepression of the phosphate transport and polyphosphate-synthesizing systems as well as alkaline phosphatase occurs in phosphate shortage, but that the breakdown of polyphosphate in this organism is regulated by modulation of existing enzyme activity. PMID:227842

  17. PROCESS FOR THE RECOVERY OF URANIUM FROM PHOSPHATIC ORE

    DOEpatents

    Long, R.L.

    1959-04-14

    A proccss is described for the recovery of uranium from phosphatic products derived from phosphatic ores. It has been discovered that certain alkyl phosphatic, derivatives can be employed in a direct solvent extraction operation to recover uranium from solid products, such as superphosphates, without first dissolving such solids. The organic extractants found suitable include alkyl derivatives of phosphoric, pyrophosphoric, phosof the derivative contains from 4 to 7 carbon atoms. A diluent such as kerosene is also used.

  18. Enriching vermicompost by nitrogen fixing and phosphate solubilizing bacteria.

    PubMed

    Kumar, V; Singh, K P

    2001-01-01

    The effect of inoculation of vermicompost with nitrogen-fixing Azotobacter chroococcum strains, Azospirillum lipoferum and the phosphate solubilizing Pseudomonas striata on N and P contents of the vermicompost was assessed. Inoculation of N2 fixing bacteria into vermicompost increased contents of N and P. Enriching vermicompost with rock phosphate improved significantly the available P when inoculated with P. striata. During the incubation period, the inoculated bacterial strains proliferated rapidly, fixed N and solubilized added and native phosphate.

  19. Sedimentary phosphate method for estimating paleosalinities: a paleontological assumption.

    PubMed

    Guber, A L

    1969-11-01

    Paleosalinity values in certain rocks determined by the sedimentary phosphate method differ from salinity estimates based upon contained fossil assemblages, geochemical methods, and existing stratigraphic controls. Some anomalous values are related to the abundance of fossil organisms known to be concentrators of calcium phosphate. Because of the abundance and diversity of organisms which might introduce significant errors into paleosalinity estimates, the sedimentary phosphate method seemingly is of limited applicability.

  20. Studies of inositol 1-phosphate analogues as inhibitors of the phosphatidylinositol phosphate synthase in mycobacteria.

    PubMed

    Morii, Hiroyuki; Okauchi, Tatsuo; Nomiya, Hiroki; Ogawa, Midori; Fukuda, Kazumasa; Taniguchi, Hatsumi

    2013-03-01

    We previously reported a novel pathway for the biosynthesis of phosphatidylinositol in mycobacteria via phosphatidylinositol phosphate (PIP) [Morii H., Ogawa, M., Fukuda, K., Taniguchi, H., and Koga, Y (2010) J. Biochem. 148, 593-602]. PIP synthase in the pathway is a promising target for the development of new anti-mycobacterium drugs. In the present study, we evaluated the characteristics of the PIP synthase of Mycobacterium tuberculosis. Four types of compounds were chemically synthesized based on the assumption that structural homologues of inositol 1-phosphate, a PIP synthase substrate, would act as PIP synthase inhibitors, and the results confirmed that all synthesized compounds inhibited PIP synthase activity. The phosphonate analogue of inositol 1-phosphate (Ino-C-P) had the greatest inhibitory effect among the synthesized compounds examined. Kinetic analysis indicated that Ino-C-P acted as a competitive inhibitor of inositol 1-phosphate. The IC(50) value for Ino-C-P inhibition of the PIP synthase activity was estimated to be 2.0 mM. Interestingly, Ino-C-P was utilized in the same manner as the normal PIP synthase substrate, leading to the synthesis of a phosphonate analogue of PIP (PI-C-P), which had a structure similar to that of the natural product, PIP. In addition, PI-C-P had high inhibitory activity against PIP synthase.

  1. Interactions between organic amendments and phosphate fertilizers modify phosphate sorption processes in an acid soil

    SciTech Connect

    Sckefe, C.R.; Patti, A.F.; Clune, T.S.; Jackson, W.R.

    2008-07-15

    To determine how organic amendments and phosphate fertilizers interact to modify P sorption processes, three phosphate fertilizers were applied to lignite- and compost-amended acid soil and incubated for either 3 or 26 days. The fertilizers applied were potassium dihydrogen phosphate, triple superphosphate, and diammonium phosphate (DAP). After 3 days of incubation, sorption of all three P sources was decreased in the lignite-amended treatments, whereas P sorption was increased in the compost-amended treatments. Increased incubation time (26 days) resulted in significantly decreased P sorption when DAP was added to lignite-amended treatments. Addition of triple superphosphate increased P sorption in lignite- and compost-amended treatments and decreased solution pH compared with DAP application. In addition to the effect of P source, differences in P sorption between the lignite- and compost-amended treatments were driven by differences in solution chemistry, predominantly solution pH and cation dynamics. Soil amendment and fertilizer addition also increased microbial activity in the incubation systems, as measured by carbon dioxide respiration. It is proposed that the combination of lignite and DAP may contribute to decreased P sorption in acid soils, with the positive effects likely caused by both chemical and biological processes, including the formation of soluble organic-metal complexes.

  2. Glycerophosphodiester phosphodiesterases play an important role in phosphate recycling and phosphate sensing in white lupin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    White lupin (Lupinus albus L.), a well adapted species to phosphate (Pi) impoverished soils, develops short, densely clustered lateral roots (cluster/proteoid roots) to increase Pi uptake. Here, we report two white lupin glycerophosphodiester phosphodiesterase (GPX-PDE) genes which share strong homo...

  3. Physiology of Calcium and Phosphate Metabolism: 1980 Refresher Course, Syllabus.

    ERIC Educational Resources Information Center

    Knox, Franklyn G., Ed.

    1980-01-01

    This syllabus reviews information concerning calcium and phosphate regulation. Topics of interest include the following: calcium metabolism, phosphorus metabolism, bone, parathyroid hormone, calcitonin, and vitamin D. (CS)

  4. Adsorption of phosphate from aqueous solution by hydrous zirconium oxide.

    PubMed

    Rodrigues, Liana Alvares; Maschio, Leandro José; Coppio, Luciana de Simone Cividanes; Thim, Gilmar Patrocínio; da Silva, Maria Lúcia Caetano Pinto

    2012-06-01

    Synthetic ZrO2 x nH2O was used for phosphate removal from aqueous solution. The optimum adsorbent dose obtained for phosphate adsorption on to hydrous zirconium oxide was 0.1 g. The kinetic process was described very well by a pseudo-second-order rate model. The phosphate adsorption tended to increase with the decrease in pH. The adsorption capacity increased from 61 to 66 mg g(-1) when the temperature was increased from 298 to 338 K. A phosphate desorption of approximately 74% was obtained using water at pH 12.

  5. Amorphous calcium phosphates for tooth mineralization.

    PubMed

    Tung, Ming S; Eichmiller, Frederick C

    2004-09-01

    The destruction of tooth structure through caries and erosive processes is due to two types of acidic challenges that affect the tooth in different ways. Acidic attack by cariogenic bacteria initially produces subsurface lesions that weaken the enamel and, if left unchecked, can progress through the enamel and dentin and eventually into the pulpal cavity. Erosive attack by acidic foods and beverages removes mineral from the surface of enamel and initially causes dulling and loss of tooth luster; if left unchecked, it can progress to a more severe loss of enamel thickness and contour. This article focuses on the potential means of improving the cosmetic appearance of teeth by depositing mineral into surface defects. Several approaches use the unique properties of amorphous calcium phosphate (ACP) compounds, which have the highest rates of formation and dissolution among all the calcium phosphates. ACP has been shown to rapidly hydrolyze to form apatite, similar to carbonated apatite, the tooth mineral. Products containing ACP or ingredients that form ACP can include toothpastes, mouth rinses, artificial saliva, chewing gums, topically applied coatings, and other vehicles for topical use. When applied, they readily precipitate ACPs on and into tooth-surface defects. These products hopefully will provide users with new tools to restore and enhance the smoothness and luster of their teeth.

  6. Arabinose 5-phosphate covalently inhibits transaldolase.

    PubMed

    Light, Samuel H; Anderson, Wayne F

    2014-03-01

    Arabinose 5-phosphate (A5P) is the aldopentose version of the ketohexose fructose 6-phosphate (F6P), having identical stereochemistry but lacking atoms corresponding to the 1-carbon and 1-hydroxyl. Despite structural similarity and conservation of the reactive portion of F6P, F6P acts as a substrate whereas A5P is reported to be an inhibitor of transaldolase. To address the lack of A5P reactivity we determined a crystal structure of the Francisella tularensis transaldolase in complex with A5P. This structure reveals that like F6P, A5P forms a covalent Schiff base with active site Lys135. Unlike F6P, A5P binding fails to displace an ordered active site water molecule. Retaining this water necessitates conformational changes at the A5P-protein linkage that possibly hinder reactivity. The findings presented here show the basis of A5P inhibition and suggest an unusual mechanism of competitive, reversible-covalent transaldolase regulation.

  7. Allosteric dominance in carbamoyl phosphate synthetase.

    PubMed

    Braxton, B L; Mullins, L S; Raushel, F M; Reinhart, G D

    1999-02-01

    A linked-function analysis of the allosteric responsiveness of carbamoyl phosphate synthetase (CPS) from E. coli was performed by following the ATP synthesis reaction at low carbamoyl phosphate concentration. All three allosteric ligands, ornithine, UMP, and IMP, act by modifying the affinity of CPS for the substrate MgADP. Individually ornithine strongly promotes, and UMP strongly antagonizes, the binding of MgADP. IMP causes only a slight inhibition at 25 degreesC. When both ornithine and UMP were varied, models which presume a mutually exclusive binding relationship between these ligands do not fit the data as well as does one which allows both ligands (and substrate) to bind simultaneously. The same result was obtained with ornithine and IMP. By contrast, the actions of UMP and IMP together must be explained with a competitive model, consistent with previous reports that UMP and IMP bind to the same site. When ornithine is bound to the enzyme, its activation dominates the effects when either UMP or IMP is also bound. The relationship of this observation to the structure of CPS is discussed. PMID:9931004

  8. Expanding sapphyrin: towards selective phosphate binding.

    PubMed

    Katayev, Evgeny A; Boev, Nikolay V; Myshkovskaya, Ekaterina; Khrustalev, Victor N; Ustynyuk, Yu A

    2008-01-01

    The anion-templated syntheses and binding properties of novel macrocyclic oligopyrrole receptors in which pyrrole rings are linked through amide or imine bonds are described. The efficient synthesis was accomplished by anion-templated [1+1] Schiff-base condensation and acylation macrocyclization reactions. Free receptors and their host-guest complexes with hydrochloric acid, acetic acid, tetrabutylammonium chloride, and hydrogen sulfate were analyzed by single-crystal X-ray diffraction analysis. Stability constants with different tetrabutylammonium salts of inorganic acids were determined by standard 1H NMR and UV/Vis titration techniques in [D6]DMSO/0.5% water solution. According to the titration data, receptors containing three pyrrole rings (10 and 12) exhibit high affinity (log Ka=5-7) for bifluoride, acetate, and dihydrogen phosphate, and interact weakly with chloride and hydrogen sulfate. The amido-bipyrrole receptors 11 and 13 with four pyrrole rings exhibit 10(4)- and 10(2)-fold selectivity for dihydrogen phosphate, respectively, as inferred from competitive titrations in the presence of tetrabutylammonium acetate.

  9. Phosphatic fertiliser poisoning of sheep: experimental studies.

    PubMed

    O'Hara, P J; McCausland, I P; Coup, M R

    1982-11-01

    The toxicity of serpentine phosphate and superphosphate for non-pregnant dry ewes, pregnant ewes and lactating ewes was investigated by oral dosing. An attempt was made to reproduce a natural episode of poisoning by exposing pregnant and lactating ewes to topdressed pasture. A total dose in the range of 1200 to 1800 g of serpentine phosphate was required to kill two ewes and it was concluded that natural episodes of poisoning with this material are unlikely. The toxic process was similar to that caused by superphosphate. The LD50 of superphosphate was estimated to be in the range of 5 to 6 g/kg and a dose in the range of 200 to 300 g was sufficient to kill most sheep. The apparently greater susceptibility of pregnant and lactating sheep to poisoning suggested by the study of natural outbreaks was not demonstrated in these experiments, but the numbers of experimental animals may have been too small to detect differing susceptibility. The clinical disease resembled that seen in natural episodes; anorexia, diarrhoea, progressive depression and death in a period of 5 to 8 days after the start of dosing. Sublethal doses produced a transient diarrhoea and, in two sheep, a severe wool-break. The principal biochemical changes were hyperphosphataemia and evidence of renal failure (oliguria, uraemia, azotaemia). Gross lesions were not consistently present but included abomasal ulceration and renal cortical swelling and pallor. The histopathological evidence of renal tubular obstruction by flocculant eosinophilic casts was characteristic. PMID:16030836

  10. Elemental analysis of Egyptian phosphate fertilizer components.

    PubMed

    El-Bahi, S M; El-Dine, N Walley; El-Shershaby, A; Sroor, A

    2004-03-01

    The accumulation of certain elements in vitally important media such as water, soil, and food is undesirable from the medical point of view. It is clear that the fertilizers vary widely in their heavy metals and uranium content. A shielded high purity germanium HPGe detector has been used to measure the natural concentration of 238U, 232Th, and 40K activities in the phosphate fertilizer and its components collected from Abu-Zaabal fertilizers and chemical industries in Egypt. The concentration ranges were 134.97-681.11 Bq kg(-1), 125.23-239.26 Bq kg(-1), and 446.11-882.45 Bq kg(-1) for 238U, 232Th, and 40K, respectively. The absorbed dose rate and external hazard index were found to be from 177.14 to 445.90 nGy h(-1) and 1.03 to 2.71 nGy y(-1), respectively. The concentrations of 22 elements (Be, Na, Mg, Si, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Zr, Mo, Cd, Ba) in the samples under investigation were determined by inductively coupled plasma optical-emission spectrometry (ICP-OES). The results for the input raw materials (rock phosphate, limestone and sulfur) and the output product as final fertilizer are presented and discussed. PMID:14982231

  11. Bacterial phosphating of mild (unalloyed) steel.

    PubMed

    Volkland, H P; Harms, H; Müller, B; Repphun, G; Wanner, O; Zehnder, A J

    2000-10-01

    Mild (unalloyed) steel electrodes were incubated in phosphate-buffered cultures of aerobic, biofilm-forming Rhodococcus sp. strain C125 and Pseudomonas putida mt2. A resulting surface reaction leading to the formation of a corrosion-inhibiting vivianite layer was accompanied by a characteristic electrochemical potential (E) curve. First, E increased slightly due to the interaction of phosphate with the iron oxides covering the steel surface. Subsequently, E decreased rapidly and after 1 day reached -510 mV, the potential of free iron, indicating the removal of the iron oxides. At this point, only scattered patches of bacteria covered the surface. A surface reaction, in which iron was released and vivianite precipitated, started. E remained at -510 mV for about 2 days, during which the vivianite layer grew steadily. Thereafter, E increased markedly to the initial value, and the release of iron stopped. Changes in E and formation of vivianite were results of bacterial activity, with oxygen consumption by the biofilm being the driving force. These findings indicate that biofilms may protect steel surfaces and might be used as an alternative method to combat corrosion.

  12. Phosphate transporter expression in Holstein cows.

    PubMed

    Foote, A P; Lambert, B D; Brady, J A; Muir, J P

    2011-04-01

    Phosphorus nutrition in cattle is increasingly becoming an important topic because excess dietary P is excreted in manure and can be washed into surface water, causing increased algal growth and eutrophication. However, little is known about the mechanism or regulation of P absorption in dairy cattle. Phosphorus transporters have been characterized in other species and homologous genes have been found to be expressed in bovine cell cultures. However, no other information is available regarding the active transport of phosphate in the digestive tract of cattle. The objective of this study was to determine the patterns of expression of a known phosphate transporter, NaPi-IIb, in 4 sections of the small intestine of Holstein cows. Ribonucleic acid was isolated from the duodenal, proximal jejunal, distal jejunal, and ileal mucosa of 20 Holstein cows. Relative amounts of NaPi-IIb mRNA expression were determined using real-time reverse-transcription PCR. Expression of NaPi-IIb was highest in the 2 distal sections and almost absent in the proximal sections. Expression did not differ between the 2 proximal sections or the 2 distal sections. These data suggest that a Na+-dependent secondary active P transport system is not responsible for P absorption in the proximal portion of the bovine small intestine, whereas it does contribute to the P absorbed in the distal sections of the bovine small intestine.

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

    PubMed Central

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

    1991-01-01

    Calcium hydroxyapatite can be a significant component of black pigment gallstones. Diverse molecules that bind calcium phosphate inhibit hydroxyapatite precipitation. Because glycine-conjugated bile acids, but not their taurine counterparts, bind calcium phosphate, we studied whether glycochenodeoxycholic acid inhibits calcium hydroxyapatite formation. Glycochenodeoxycholic acid (2 mM) totally inhibited transformation of amorphous calcium phosphate microprecipitates to macroscopic crystalline calcium hydroxyapatite. This inhibition was not mediated by decreased Ca2+ activity. Taurocholic acid (2-12 mM) did not affect hydroxyapatite formation, but antagonized glycochenodeoxycholic acid. Both amorphous and crystalline precipitates contained a surface fraction relatively rich in phosphate. The surface phosphate content was diminish by increasing glycochenodeoxycholic acid concentrations, and this relationship was interpreted as competition between bile acid and HPO4(-4) for binding sites on the calcium phosphate surface. A phosphate-rich crystal surface was associated with rapid transition from amorphous to crystalline states. These results indicate that glycochenodeoxycholic acid prevents transformation of amorphous calcium phosphate to crystalline hydroxyapatite by competitively inhibiting the accumulation of phosphate on the crystal embryo surface. PMID:1655828

  14. Characterization of three putative xylulose 5-phosphate/fructose 6-phosphate phosphoketolases in the cyanobacterium Anabaena sp. PCC 7120.

    PubMed

    Moriyama, Takashi; Tajima, Naoyuki; Sekine, Kohsuke; Sato, Naoki

    2015-01-01

    Xylulose 5-phosphate/fructose 6-phosphate phosphoketolase (Xfp) is a key enzyme in the central carbohydrate metabolism in heterofermentative bacteria, in which enzymatic property of Xfps is well characterized. This is not the case in other microbes. The cyanobacterium Anabaena sp. PCC 7120 possesses three putative genes encoding Xfp, all1483, all2567, and alr1850. We purified three putative Xfps as recombinant proteins. The results of gel filtration indicated that these proteins form homomultimer complex. All1483 and All2567 showed phosphoketolase activity, whereas Alr1850 did not show the activity. Kinetic analyses demonstrated that substrates, fructose 6-phosphate and inorganic phosphate, are cooperatively bound to enzymes positively and negatively, respectively.

  15. Erythritol feeds the pentose phosphate pathway via three new isomerases leading to D-erythrose-4-phosphate in Brucella

    PubMed Central

    Barbier, Thibault; Collard, François; Zúñiga-Ripa, Amaia; Moriyón, Ignacio; Godard, Thibault; Becker, Judith; Wittmann, Christoph; Van Schaftingen, Emile; Letesson, Jean-Jacques

    2014-01-01

    Erythritol is an important nutrient for several α-2 Proteobacteria, including N2-fixing plant endosymbionts and Brucella, a worldwide pathogen that finds this four-carbon polyol in genital tissues. Erythritol metabolism involves phosphorylation to l-erythritol-4-phosphate by the kinase EryA and oxidation of the latter to l-3-tetrulose 4-phosphate by the dehydrogenase EryB. It is accepted that further steps involve oxidation by the putative dehydrogenase EryC and subsequent decarboxylation to yield triose-phosphates. Accordingly, growth on erythritol as the sole C source should require aldolase and fructose-1,6-bisphosphatase to produce essential hexose-6-monophosphate. However, we observed that a mutant devoid of fructose-1,6-bisphosphatases grew normally on erythritol and that EryC, which was assumed to be a dehydrogenase, actually belongs to the xylose isomerase superfamily. Moreover, we found that TpiA2 and RpiB, distant homologs of triose phosphate isomerase and ribose 5-phosphate isomerase B, were necessary, as previously shown for Rhizobium. By using purified recombinant enzymes, we demonstrated that l-3-tetrulose-4-phosphate was converted to d-erythrose 4-phosphate through three previously unknown isomerization reactions catalyzed by EryC (tetrulose-4-phosphate racemase), TpiA2 (d-3-tetrulose-4-phosphate isomerase; renamed EryH), and RpiB (d-erythrose-4-phosphate isomerase; renamed EryI), a pathway fully consistent with the isotopomer distribution of the erythrose-4-phosphate-derived amino acids phenylalanine and tyrosine obtained from bacteria grown on 13C-labeled erythritol. d-Erythrose-4-phosphate is then converted by enzymes of the pentose phosphate pathway to glyceraldehyde 3-phosphate and fructose 6-phosphate, thus bypassing fructose-1,6-bisphosphatase. This is the first description to our knowledge of a route feeding carbohydrate metabolism exclusively via d-erythrose 4-phosphate, a pathway that may provide clues to the preferential metabolism of

  16. Bacterial community structures of phosphate-removing and non-phosphate-removing activated sludges from sequencing batch reactors.

    PubMed Central

    Bond, P L; Hugenholtz, P; Keller, J; Blackall, L L

    1995-01-01

    The bacterial community structures of phosphate- and non-phosphate-removing activated sludges were compared. Sludge samples were obtained from two sequencing batch reactors (SBRs), and 16S rDNA clone libraries of the bacterial sludge populations were established. Community structures were determined by phylogenetic analyses of 97 and 92 partial clone sequences from SBR1 (phosphate-removing sludge) and SBR2 (non-phosphate-removing sludge), respectively. For both sludges, the predominant bacterial group with which clones were affiliated was the beta subclass of the proteobacteria. Other major groups represented were the alpha proteobacterial subclass, planctomycete group, and Flexibacter-Cytophaga-Bacteroides group. In addition, several clone groups unaffiliated with known bacterial assemblages were identified in the clone libraries. Acinetobacter spp., thought to be important in phosphate removal in activated sludge, were poorly represented by clone sequences in both libraries. Differences in community structure were observed between the phosphate- and non-phosphate-removing sludges; in particular, the Rhodocyclus group within the beta subclass was represented to a greater extent in the phosphate-removing community. Such differences may account for the differing phosphate-removing capabilities of the two activated sludge communities. PMID:7544094

  17. Erythritol feeds the pentose phosphate pathway via three new isomerases leading to D-erythrose-4-phosphate in Brucella.

    PubMed

    Barbier, Thibault; Collard, François; Zúñiga-Ripa, Amaia; Moriyón, Ignacio; Godard, Thibault; Becker, Judith; Wittmann, Christoph; Van Schaftingen, Emile; Letesson, Jean-Jacques

    2014-12-16

    Erythritol is an important nutrient for several α-2 Proteobacteria, including N2-fixing plant endosymbionts and Brucella, a worldwide pathogen that finds this four-carbon polyol in genital tissues. Erythritol metabolism involves phosphorylation to L-erythritol-4-phosphate by the kinase EryA and oxidation of the latter to L-3-tetrulose 4-phosphate by the dehydrogenase EryB. It is accepted that further steps involve oxidation by the putative dehydrogenase EryC and subsequent decarboxylation to yield triose-phosphates. Accordingly, growth on erythritol as the sole C source should require aldolase and fructose-1,6-bisphosphatase to produce essential hexose-6-monophosphate. However, we observed that a mutant devoid of fructose-1,6-bisphosphatases grew normally on erythritol and that EryC, which was assumed to be a dehydrogenase, actually belongs to the xylose isomerase superfamily. Moreover, we found that TpiA2 and RpiB, distant homologs of triose phosphate isomerase and ribose 5-phosphate isomerase B, were necessary, as previously shown for Rhizobium. By using purified recombinant enzymes, we demonstrated that L-3-tetrulose-4-phosphate was converted to D-erythrose 4-phosphate through three previously unknown isomerization reactions catalyzed by EryC (tetrulose-4-phosphate racemase), TpiA2 (D-3-tetrulose-4-phosphate isomerase; renamed EryH), and RpiB (D-erythrose-4-phosphate isomerase; renamed EryI), a pathway fully consistent with the isotopomer distribution of the erythrose-4-phosphate-derived amino acids phenylalanine and tyrosine obtained from bacteria grown on (13)C-labeled erythritol. D-erythrose-4-phosphate is then converted by enzymes of the pentose phosphate pathway to glyceraldehyde 3-phosphate and fructose 6-phosphate, thus bypassing fructose-1,6-bisphosphatase. This is the first description to our knowledge of a route feeding carbohydrate metabolism exclusively via D-erythrose 4-phosphate, a pathway that may provide clues to the preferential metabolism of

  18. Silica-Supported Oligomeric Benzyl Phosphate (Si-OBP) and Triazole Phosphate (Si-OTP) Alkylating Reagents.

    PubMed

    Maity, Pradip K; Faisal, Saqib; Rolfe, Alan; Stoianova, Diana; Hanson, Paul R

    2015-10-16

    The syntheses of silica-supported oligomeric benzyl phosphates (Si-OBP(n)) and triazole phosphates (Si-OTP(n)) using ring-opening metathesis polymerization (ROMP) for use as efficient alkylating reagents is reported. Ease of synthesis and grafting onto the surface of norbornenyl-tagged (Nb-tagged) silica particles has been demonstrated for benzyl phosphate and triazole phosphate monomers. It is shown that these silica polymer hybrid reagents, Si-OBP(n) and Si-OTP(n), can be used to carry out alkylation reactions with an array of different nucleophiles to afford the corresponding benzylated and (triazolyl)methylated products in good yield and high purity. PMID:26430955

  19. Phosphate removal using sludge from fuller's earth production.

    PubMed

    Moon, Yong Hee; Kim, Jae Gon; Ahn, Joo Sung; Lee, Gyoo Ho; Moon, Hi-Soo

    2007-05-01

    This study assesses the phosphate removal capacity and mechanism of precipitation or adsorption from aqueous solutions in batch experiments by an industrial sludge containing gypsum (CaSO(4).2H(2)O) obtained as a by-product from a fuller's earth process. The potential capacity for phosphate removal was tested using various solution concentrations, pH values, reaction times, and amount of sludge. The maximum phosphate adsorption capacity calculated using the Langmuir equation was 2.0 g kg(-1). The pH for the maximum adsorption by the sludge was neutral to alkaline (pH 7-12). Over 99% of phosphate was removed from a phosphate solution of 30 mg L(-1) using 0.15 g of sludge in a 9-h reaction. Sulfate (SO(4)(2-)) concentration increased with increasing initial phosphate concentration, possibly because of dissolution of gypsum and adsorption of both sulfate and phosphate. At high phosphate concentration (>1000 mg L(-1)), relative constant concentration of Ca(2+) was not consistent with adsorption of the most important phosphate removal mechanism. Results suggest that precipitation of calcium phosphate is principally responsible for phosphate removal under its high concentration. Agglomerated precipitate in the reaction sludge was observed by SEM and identified as brushite (CaHPO(4).2H(2)O) by XRD, FT-IR, and DTA. Based on thermodynamic considerations, it is suggested that the brushite will readily transform to more stable phases, such as hydroxyapatite (Ca(5)(PO(4))(3).OH).

  20. Phosphate removal using sludge from fuller's earth production.

    PubMed

    Moon, Yong Hee; Kim, Jae Gon; Ahn, Joo Sung; Lee, Gyoo Ho; Moon, Hi-Soo

    2007-05-01

    This study assesses the phosphate removal capacity and mechanism of precipitation or adsorption from aqueous solutions in batch experiments by an industrial sludge containing gypsum (CaSO(4).2H(2)O) obtained as a by-product from a fuller's earth process. The potential capacity for phosphate removal was tested using various solution concentrations, pH values, reaction times, and amount of sludge. The maximum phosphate adsorption capacity calculated using the Langmuir equation was 2.0 g kg(-1). The pH for the maximum adsorption by the sludge was neutral to alkaline (pH 7-12). Over 99% of phosphate was removed from a phosphate solution of 30 mg L(-1) using 0.15 g of sludge in a 9-h reaction. Sulfate (SO(4)(2-)) concentration increased with increasing initial phosphate concentration, possibly because of dissolution of gypsum and adsorption of both sulfate and phosphate. At high phosphate concentration (>1000 mg L(-1)), relative constant concentration of Ca(2+) was not consistent with adsorption of the most important phosphate removal mechanism. Results suggest that precipitation of calcium phosphate is principally responsible for phosphate removal under its high concentration. Agglomerated precipitate in the reaction sludge was observed by SEM and identified as brushite (CaHPO(4).2H(2)O) by XRD, FT-IR, and DTA. Based on thermodynamic considerations, it is suggested that the brushite will readily transform to more stable phases, such as hydroxyapatite (Ca(5)(PO(4))(3).OH). PMID:17030413

  1. Hybrid calcium phosphate coatings for implants

    NASA Astrophysics Data System (ADS)

    Malchikhina, Alena I.; Shesterikov, Evgeny V.; Bolbasov, Evgeny N.; Ignatov, Viktor P.; Tverdokhlebov, Sergei I.

    2016-08-01

    Monophasic biomaterials cannot provide all the necessary functions of bones or other calcined tissues. It is necessary to create for cancer patients the multiphase materials with the structure and composition simulating the natural bone. Such materials are classified as hybrid, obtained by a combination of chemically different components. The paper presents the physical, chemical and biological studies of coatings produced by hybrid technologies (HT), which combine primer layer and calcium phosphate (CaP) coating. The first HT type combines the method of vacuum arc titanium primer layer deposition on a stainless steel substrate with the following micro-arc oxidation (MAO) in phosphoric acid solution with addition of calcium compounds to achieve high supersaturated state. MAO CaP coatings feature high porosity (2-8%, pore size 5-7 µm) and surface morphology with the thickness greater than 5 µm. The thickness of Ti primer layer is 5-40 µm. Amorphous MAO CaP coating micro-hardness was measured at maximum normal load Fmax = 300 mN. It was 3.1 ± 0.8 GPa, surface layer elasticity modulus E = 110 ± 20 GPa, roughness Ra = 0.9 ± 0.1 µm, Rz = 7.5 ± 0.2 µm, which is less than the titanium primer layer roughness. Hybrid MAO CaP coating is biocompatible, able to form calcium phosphates from supersaturated body fluid (SBF) solution and also stimulates osteoinduction processes. The second HT type includes the oxide layer formation by thermal oxidation and then CaP target radio frequency magnetron sputtering (RFMS). Oxide-RFMS CaP coating is a thin dense coating with good adhesion to the substrate material, which can be used for metal implants. The RFMS CaP coating has thickness 1.6 ± 0.1 µm and consists of main target elements calcium and phosphorus and Ca/P ratio 2.4. The second HT type can form calcium phosphates from SBF solution. In vivo study shows that hybrid RFMS CaP coating is biocompatible and produces fibrointegration processes.

  2. Odontoblast phosphate and calcium transport in dentinogenesis.

    PubMed

    Lundquist, Patrik

    2002-01-01

    It has been suggested that odontoblasts are instrumental in translocating Ca2+ and inorganic phosphate (Pi) ions during the mineralization of dentin. The aim of this thesis was, therefore, to study the expression of components of the transcellular ion transport system, Na+/Ca2+ exchangers and Na(+)-Pi contransporters, in odontoblastic and osteoblastic cells. Their activity was assayed in osteoblast-like cells and in the recently developed MRPC-1 odontoblast-like cell line. To assess the relationship between ion transport and mineralization, Ca2+ and Pi uptake activities were determined in mineralizing cultures of MRPC-1 cells. Osteoblastic and odontoblastic cells showed an identical expression pattern of Na+/Ca2+ exchanger splice-variants, NCX1.3, NCX1.7 and NCX1.10, derived from the NCX1 gene, while NCX2 was not expressed. The cells showed a high sodium-dependent calcium extrusion activity. Regarding Na(+)-Pi cotransporter expression, Glvr-1, Ram-1 and the two high capacity cotransporters Npt-2a and Npt-2b were found to be expressed in odontoblasts and MRPC-1 cells. Osteoblast-like cells differed from this in expressing the Npt-1 but not the Ram-1 gene but were otherwise identical to the odontoblastic cells. Odontoblast-like cells exhibited almost twice the sodium-dependent Pi uptake activity of osteoblast-like cells. The presence of NaPi-2a and NaPi-2b, gene products of Npt-2a and Npt-2b, was verified in vivo by immunohistochemistry on mouse teeth. Both cotransporters could be detected in fully differentiated, polarized odontoblasts but not in preodontoblasts prior to dentin formation. Both cotransporters were detected in adjacent bone and in ameloblasts. Studying ion uptake in mineralizing MRPC-1 cultures, large changes were detected concomitant with the onset of mineral formation, when phosphate uptake increased by 400% while calcium uptake started to decline. The increase in Pi uptake was found to be due to activation of the NaPi-2a cotransporter. MRPC-1 cells

  3. Uraniferous Phosphates: Resource, Security Risk, or Contaminant

    SciTech Connect

    LeMone, D.V.; Goodell, Ph.C.; Gibbs, S.G.; Winston, J.W.

    2008-07-01

    The escalation of the price of uranium (U) yellow cake (summer high = $130/0.454 kg (lb) has called into question the continuing availability of sufficient stockpiles and ores to process. As was developed during the years following World War II, the establishment and maintenance of a strategic inventory is a reasonable consideration for today. Therefore, it becomes critical to look at potential secondary resources beyond the classical ore suites now being utilized. The most economically viable future secondary source seems to be the byproducts of the beneficiation of phosphoric acids derived from phosphate ores. Phosphorous (P) is an essential nutrient for plants; its deficiency can result in highly restrictive limitations in crop productivity. Acidic soils in tropical and subtropical regions of the world are often P deficient with high P-sorption (fixation) capacities. To correct this deficiency, efficient water-soluble P fertilizers are required. The use of raw phosphate rocks not only adds phosphate but also its contained contaminants, including uranium to the treated land. Another immediate difficulty is phosphogypsum, the standard byproduct of simple extraction. It, for practical purposes, has been selectively classified as TENORM by regulators. The imposition of these standards presents major current and future disposal and re-utilization problems. Therefore, establishing an economically viable system that allows for uranium byproduct extraction from phosphoric acids is desirable. Such a system would be dependent on yellow cake base price stability, reserve estimates, political conditions, nation-state commitment, and dependence on nuclear energy. The accumulation of yellow cake from the additional extraction process provides a valuable commodity and allows the end acid to be a more environmentally acceptable product. The phosphogypsum already accumulated, as well as that which is in process, will not make a viable component for a radiation disposal devise

  4. Long-term results with different bone substitutes used for sinus floor elevation.

    PubMed

    Velich, Norbert; Németh, Zsolt; Tóth, Christian; Szabó, György

    2004-01-01

    One of the surgical procedures preceding implantation is elevation of the base of the maxillary sinus. Numerous bone substituting materials (grafts) may be used for this purpose, including autogenous bone, heterografts, xenogenous bone, and synthetic materials alone or in combination or mixed with growth factors and bone morphogenetic protein (BMP) preparations. A study of the frequencies of the failures (graft material resorption or implant loss) after sinus elevations with various graft materials or their combinations was conducted. In the 5-year period from 1996 through 2001, a follow-up investigation of 810 maxillary sinus augmentations was performed, in which the sinus elevations involved the use of autogenous bone, a calcium carbonate-coated polymer, hydroxylapatite of algal origin, calcium carbonate gel produced from coral or beta-tricalcium phosphate alone, autogenous bone mixed with these bone substitutes, or a combination of beta-tricalcium phosphate and platelet-rich plasma. The incidences of graft resorption and implant loss after the augmentations with various bone substitutes were recorded. Total resorption (disappearance) of the bone substitute material was observed in 2.7% of the cases. An essential difference was not experienced between the various bone substitutes from this aspect, with the exception of the gel-state calcium carbonate, where 40% of the grafts were resorbed. In total, 5.46% of the implants were lost; the differences between the various materials were not significant. PMID:14704560

  5. Assessment of implant stability following sinus lift procedures with different grafting materials

    PubMed Central

    Jelušić, Damir; Plančak, Darije

    2014-01-01

    Objective The objective of this research was to evaluate implant stability following sinus lift with two grafting materials, and to compare it with the results obtained for the implants placed in a pristine posterior maxilla. Materials and methods The study included 44 healthy patients with an existing indication for sinus lift procedure (test group). 46 implants were placed following sinus lift with a pure-phase beta-tricalcium phosphate, while 39 implants were placed following augmentation with 60% hydroxyapatite with 40% beta-tricalcium phosphate material. The control group consisted of 48 healthy patients who were treated with 85 implants but without bone augmentation in posterior maxilla. Astra Tech OsseoSpeed implants were placed in all subjects. Resonance frequency analysis was used in both groups for determining implant stability 4 months after insertion. A mean implant stability quotient (ISQ) was calculated on the basis of 3 measurements. Results No statistical difference was observed in ISQ values of implants placed with and without augmentation procedure (p=0,789). Statistically significant difference was not found when ISQ values of implants placed following particular grafting material were compared with ISQ values of corresponding implants in a pristine bone (p=0.697 and p=0.402). Conclusions This study demonstrated that the implant stability is comparable among implants placed in the posterior maxilla regardless of sinus lift and grafting procedure. Implants placed in the grafted posterior maxilla can be predictably loaded as the implants placed in a non-grafted, pristine maxilla.

  6. Chemistry Misconceptions Associated with Understanding Calcium and Phosphate Homeostasis

    ERIC Educational Resources Information Center

    Cliff, William H.

    2009-01-01

    Successful learning of many aspects in physiology depends on a meaningful understanding of fundamental chemistry concepts. Two conceptual diagnostic questions measured student understanding of the chemical equilibrium underlying calcium and phosphate homeostasis. One question assessed the ability to predict the change in phosphate concentration…

  7. Sodium-Dependent Phosphate Transporters in Osteoclast Differentiation and Function

    PubMed Central

    Dolder, Silvia; Siegrist, Mark; Wagner, Carsten A.; Biber, Jürg; Hernando, Nati; Hofstetter, Willy

    2015-01-01

    Osteoclasts are multinucleated bone degrading cells. Phosphate is an important constituent of mineralized bone and released in significant quantities during bone resorption. Molecular contributors to phosphate transport during the resorptive activity of osteoclasts have been controversially discussed. This study aimed at deciphering the role of sodium-dependent phosphate transporters during osteoclast differentiation and bone resorption. Our studies reveal RANKL-induced differential expression of sodium-dependent phosphate transport protein IIa (NaPi-IIa) transcript and protein during osteoclast development, but no expression of the closely related NaPi-IIb and NaPi-IIc SLC34 family isoforms. In vitro studies employing NaPi-IIa-deficient osteoclast precursors and mature osteoclasts reveal that NaPi-IIa is dispensable for bone resorption and osteoclast differentiation. These results are supported by the analysis of structural bone parameters by high-resolution microcomputed tomography that yielded no differences between adult NaPi-IIa WT and KO mice. By contrast, both type III sodium-dependent phosphate transporters Pit-1 and Pit-2 were abundantly expressed throughout osteoclast differentiation, indicating that they are the relevant sodium-dependent phosphate transporters in osteoclasts and osteoclast precursors. We conclude that phosphate transporters of the SLC34 family have no role in osteoclast differentiation and function and propose that Pit-dependent phosphate transport could be pivotal for bone resorption and should be addressed in further studies. PMID:25910236

  8. 40 CFR 721.10317 - Alkyl phosphate derivative (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkyl phosphate derivative (generic... Specific Chemical Substances § 721.10317 Alkyl phosphate derivative (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as...

  9. 40 CFR 721.10317 - Alkyl phosphate derivative (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkyl phosphate derivative (generic... Specific Chemical Substances § 721.10317 Alkyl phosphate derivative (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as...

  10. 40 CFR 721.10317 - Alkyl phosphate derivative (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkyl phosphate derivative (generic... Specific Chemical Substances § 721.10317 Alkyl phosphate derivative (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as...

  11. Biotemplate synthesis of monodispersed iron phosphate hollow microspheres.

    PubMed

    Cao, Feng; Li, Dongxu

    2010-03-01

    Monodispersed iron phosphate hollow microspheres with a high degree of crystallization were prepared through a facile in situ deposition method using rape pollen grains as a biotemplate. The functional group on the surface of the pollen grains could adsorb Fe(3+), which provided the nucleation sites for growth of iron phosphate nanoparticles. After being sintered at 600 degrees C for 10 h, the pollen grains were removed and iron phosphate hollow microspheres were obtained. A scanning electron microscope and x-ray diffraction were applied to characterize the morphology and crystalline structure of the pollen grains, iron phosphate-coated pollen grains and iron phosphate hollow microspheres. Differential scanning calorimetry and thermogravity analyses were performed to investigate the thermal behavior of the iron phosphate-coated pollen grains during the calcinations. Energy dispersive spectroscopy and Fourier transform infrared spectroscopy were utilized to investigate the interaction between the pollen grains and iron phosphate. The effect of the pollen wall on the surface morphology of these iron phosphate hollow microspheres was also proven in this work.

  12. 75 FR 42783 - Certain Potassium Phosphate Salts From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-22

    ..., 75 FR 16509). The hearing was held in Washington, DC, on June 2, 2010, and all persons who requested... Phosphate Salts from China: Determinations, 74 FR 61173, November 23, 2009. The Commission transmitted its... COMMISSION Certain Potassium Phosphate Salts From China Determinations On the basis of the record...

  13. 40 CFR 721.5970 - Phosphated polyarylphenol ethoxylate, potassium salt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., potassium salt. 721.5970 Section 721.5970 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.5970 Phosphated polyarylphenol ethoxylate, potassium salt. (a) Chemical... as phosphated polyarylphenol ethoxylate, potassium salt (PMN P-93-1222) is subject to reporting...

  14. Structure of RNA 3'-phosphate cyclase bound to substrate RNA.

    PubMed

    Desai, Kevin K; Bingman, Craig A; Cheng, Chin L; Phillips, George N; Raines, Ronald T

    2014-10-01

    RNA 3'-phosphate cyclase (RtcA) catalyzes the ATP-dependent cyclization of a 3'-phosphate to form a 2',3'-cyclic phosphate at RNA termini. Cyclization proceeds through RtcA-AMP and RNA(3')pp(5')A covalent intermediates, which are analogous to intermediates formed during catalysis by the tRNA ligase RtcB. Here we present a crystal structure of Pyrococcus horikoshii RtcA in complex with a 3'-phosphate terminated RNA and adenosine in the AMP-binding pocket. Our data reveal that RtcA recognizes substrate RNA by ensuring that the terminal 3'-phosphate makes a large contribution to RNA binding. Furthermore, the RNA 3'-phosphate is poised for in-line attack on the P-N bond that links the phosphorous atom of AMP to N(ε) of His307. Thus, we provide the first insights into RNA 3'-phosphate termini recognition and the mechanism of 3'-phosphate activation by an Rtc enzyme.

  15. Sodium-dependent phosphate transporters in osteoclast differentiation and function.

    PubMed

    Albano, Giuseppe; Moor, Matthias; Dolder, Silvia; Siegrist, Mark; Wagner, Carsten A; Biber, Jürg; Hernando, Nati; Hofstetter, Willy; Bonny, Olivier; Fuster, Daniel G

    2015-01-01

    Osteoclasts are multinucleated bone degrading cells. Phosphate is an important constituent of mineralized bone and released in significant quantities during bone resorption. Molecular contributors to phosphate transport during the resorptive activity of osteoclasts have been controversially discussed. This study aimed at deciphering the role of sodium-dependent phosphate transporters during osteoclast differentiation and bone resorption. Our studies reveal RANKL-induced differential expression of sodium-dependent phosphate transport protein IIa (NaPi-IIa) transcript and protein during osteoclast development, but no expression of the closely related NaPi-IIb and NaPi-IIc SLC34 family isoforms. In vitro studies employing NaPi-IIa-deficient osteoclast precursors and mature osteoclasts reveal that NaPi-IIa is dispensable for bone resorption and osteoclast differentiation. These results are supported by the analysis of structural bone parameters by high-resolution microcomputed tomography that yielded no differences between adult NaPi-IIa WT and KO mice. By contrast, both type III sodium-dependent phosphate transporters Pit-1 and Pit-2 were abundantly expressed throughout osteoclast differentiation, indicating that they are the relevant sodium-dependent phosphate transporters in osteoclasts and osteoclast precursors. We conclude that phosphate transporters of the SLC34 family have no role in osteoclast differentiation and function and propose that Pit-dependent phosphate transport could be pivotal for bone resorption and should be addressed in further studies.

  16. 40 CFR 721.6005 - Rare earth phosphate (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Rare earth phosphate (generic). 721... Substances § 721.6005 Rare earth phosphate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substances identified generically as rare earth phophate (PMNs...

  17. 40 CFR 721.6005 - Rare earth phosphate (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Rare earth phosphate (generic). 721... Substances § 721.6005 Rare earth phosphate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substances identified generically as rare earth phophate (PMNs...

  18. 40 CFR 721.6005 - Rare earth phosphate (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Rare earth phosphate (generic). 721... Substances § 721.6005 Rare earth phosphate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substances identified generically as rare earth phophate (PMNs...

  19. 40 CFR 721.6005 - Rare earth phosphate (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Rare earth phosphate (generic). 721... Substances § 721.6005 Rare earth phosphate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substances identified generically as rare earth phophate (PMNs...

  20. 40 CFR 721.6005 - Rare earth phosphate (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Rare earth phosphate (generic). 721... Substances § 721.6005 Rare earth phosphate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substances identified generically as rare earth phophate (PMNs...

  1. 2. PHOSPHATE UNLOADING BUILDING. VIEW IS TO THE NORTH. THIS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. PHOSPHATE UNLOADING BUILDING. VIEW IS TO THE NORTH. THIS STRUCTURE WAS RELOCATED TO THE SOUTH OF ITS ORIGINAL SITE IN 1993 FOR USE AS A DECONTAMINATION FACILITY WITHIN THE BUNKER HILL SUPERFUND SITE. - North Idaho Phosphate Company, Silver King Community, Kellogg, Shoshone County, ID

  2. Methane conversion process using phosphate-containing catalysts

    SciTech Connect

    Brazdil, J.F.; Teller, R.G.; Bartek, J.P.; Grasselli, R.K.

    1987-05-12

    A process is described for covering methane to a higher order hydrocarbon comprising contacting a gaseous reactant consisting of methane with a phosphate-containing catalyst for a sufficient period of time and at an effective temperature to provide the phosphate-containing catalyst consisting essentially of the higher order hydrocarbon. The catalyst is represented by a formula.

  3. 40 CFR 721.5970 - Phosphated polyarylphenol ethoxylate, potassium salt.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., potassium salt. 721.5970 Section 721.5970 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.5970 Phosphated polyarylphenol ethoxylate, potassium salt. (a) Chemical... as phosphated polyarylphenol ethoxylate, potassium salt (PMN P-93-1222) is subject to reporting...

  4. 40 CFR 721.5970 - Phosphated polyarylphenol ethoxylate, potassium salt.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., potassium salt. 721.5970 Section 721.5970 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.5970 Phosphated polyarylphenol ethoxylate, potassium salt. (a) Chemical... as phosphated polyarylphenol ethoxylate, potassium salt (PMN P-93-1222) is subject to reporting...

  5. 40 CFR 721.5970 - Phosphated polyarylphenol ethoxylate, potassium salt.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., potassium salt. 721.5970 Section 721.5970 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.5970 Phosphated polyarylphenol ethoxylate, potassium salt. (a) Chemical... as phosphated polyarylphenol ethoxylate, potassium salt (PMN P-93-1222) is subject to reporting...

  6. 40 CFR 721.5970 - Phosphated polyarylphenol ethoxylate, potassium salt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., potassium salt. 721.5970 Section 721.5970 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.5970 Phosphated polyarylphenol ethoxylate, potassium salt. (a) Chemical... as phosphated polyarylphenol ethoxylate, potassium salt (PMN P-93-1222) is subject to reporting...

  7. 46 CFR 148.220 - Ammonium nitrate-phosphate fertilizers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Ammonium nitrate-phosphate fertilizers. 148.220 Section... § 148.220 Ammonium nitrate-phosphate fertilizers. (a) This section applies to the stowage and... nitrate and containing a maximum of 0.4 percent total added combustible material or containing a...

  8. 46 CFR 148.220 - Ammonium nitrate-phosphate fertilizers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Ammonium nitrate-phosphate fertilizers. 148.220 Section... § 148.220 Ammonium nitrate-phosphate fertilizers. (a) This section applies to the stowage and... nitrate and containing a maximum of 0.4 percent total added combustible material or containing a...

  9. 46 CFR 148.220 - Ammonium nitrate-phosphate fertilizers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Ammonium nitrate-phosphate fertilizers. 148.220 Section... § 148.220 Ammonium nitrate-phosphate fertilizers. (a) This section applies to the stowage and... nitrate and containing a maximum of 0.4 percent total added combustible material or containing a...

  10. Phosphate balance in peritoneal dialysis patients: role of ultrafiltration.

    PubMed

    Granja, Carlos Andres; Juergensen, Peter; Finkelstein, Fredric O

    2009-01-01

    Current National Kidney Foundation's Disease Outcome Quality Initiative (K/DOQI) clinical practice guidelines for bone metabolism and disease in chronic kidney disease (CKD) recommend maintenance of serum phosphorus levels below 5.5 mg/dl. About 40% of patients maintained on chronic peritoneal dialysis (CPD) have phosphate levels above 5.5 mg%. The present study was designed to examine the relative contribution of ultrafiltration to phosphate removal in CPD patients. 24-hour dialysate collections were obtained in 28 CPD patients and the diffuse and ultrafiltration (UF) contributions to phosphate removal determined. 11% of phosphate removal was accounted for by UF. There was a highly significant correlation between UF rate and the % of phosphate removed by UF. The results of this study underscore the importance of individualizing the peritoneal dialysis prescription. PMID:19494614

  11. A Phosphate Starvation-Inducible Ribonuclease of Bacillus licheniformis.

    PubMed

    Nguyen, Thanh Trung; Nguyen, Minh Hung; Nguyen, Huy Thuan; Nguyen, Hoang Anh; Le, Thi Hoi; Schweder, Thomas; Jürgen, Britta

    2016-08-28

    The BLi03719 protein of Bacillus licheniformis DSM13 belongs to the most abundant extracellular proteins under phosphate starvation conditions. In this study, the function of this phosphate starvation inducible protein was determined. An amino-acid sequence analysis of the BLi03719-encoding gene showed a high similarity with genes encoding the barnase of Bacillus amyloliquefaciens FZB42 and binase-like RNase of Bacillus pumilus SARF-032. The comparison of the control strain and a BLi03719-deficient strain revealed a strongly reduced extracellular ribonuclease activity of the mutant. Furthermore, this knockout mutant exhibited delayed growth with yeast RNA as an alternative phosphate and carbon source. These results suggest that BLi03719 is an extracellular ribonuclease expressed in B. licheniformis under phosphate starvation conditions. Finally, a BLi03719 mutant showed an advantageous effect on the overexpression of the heterologous amyE gene under phosphate-limited growth conditions.

  12. Root Architecture Responses: In Search of Phosphate1

    PubMed Central

    Kanno, Satomi; Nussaume, Laurent

    2014-01-01

    Soil phosphate represents the only source of phosphorus for plants and, consequently, is its entry into the trophic chain. This major component of nucleic acids, phospholipids, and energy currency of the cell (ATP) can limit plant growth because of its low mobility in soil. As a result, root responses to low phosphate favor the exploration of the shallower part of the soil, where phosphate tends to be more abundant, a strategy described as topsoil foraging. We will review the diverse developmental strategies that can be observed among plants by detailing the effect of phosphate deficiency on primary and lateral roots. We also discuss the formation of cluster roots: an advanced adaptive strategy to cope with low phosphate availability observed in a limited number of species. Finally, we will put this work into perspective for future research directions. PMID:25341534

  13. Magnesium phosphate glass cements with ceramic-type properties

    DOEpatents

    Sugama, Toshifumi; Kukacka, Lawrence E.

    1984-03-13

    Rapid setting magnesium phosphate (Mg glass) cementitious materials consisting of magnesium phosphate cement paste, polyborax and water-saturated aggregate exhibiting rapid setting and high early strength characteristics. The magnesium glass cement is prepared from a cation-leachable powder and a bivalent metallic ion-accepting liquid such as an aqueous solution of diammonium phosphate and ammonium polyphosphate. The cation-leachable powder includes a mixture of two different magnesium oxide powders processed and sized differently which when mixed with the bivalent metallic ion-accepting liquid provides the magnesium glass cement consisting primarily of magnesium ortho phosphate tetrahydrate, with magnesium hydroxide and magnesium ammonium phosphate hexahydrate also present. The polyborax serves as a set-retarder. The resulting magnesium mono- and polyphosphate cements are particularly suitable for use as a cementing matrix in rapid repair systems for deteriorated concrete structures as well as construction materials and surface coatings for fireproof structures.

  14. Magnesium-phosphate-glass cements with ceramic-type properties

    DOEpatents

    Sugama, T.; Kukacka, L.E.

    1982-09-23

    Rapid setting magnesium phosphate (Mg glass) cementitious materials consisting of magnesium phosphate cement paste, polyborax and water-saturated aggregate, exhibits rapid setting and high early strength characteristics. The magnesium glass cement is prepared from a cation-leachable powder and a bivalent metallic ion-accepting liquid such as an aqueous solution of diammonium phosphate and ammonium polyphosphate. The cation-leachable powder includes a mixture of two different magnesium oxide powders processed and sized differently which when mixed with the bivalent metallic ion-accepting liquid provides the magnesium glass cement consisting primarily of magnesium ortho phosphate tetrahydrate, with magnesium hydroxide and magnesium ammonium phosphate hexahydrate also present. The polyborax serves as a set-retarder. The resulting magnesium mono- and polyphosphate cements are particularly suitable for use as a cementing matrix in rapid repair systems for deteriorated concrete structures as well as construction materials and surface coatings for fireproof structures.

  15. An efficient microbiological growth medium for screening phosphate solubilizing microorganisms.

    PubMed

    Nautiyal, C S

    1999-01-01

    A novel defined microbiological growth medium, National Botanical Research Institute's phosphate growth medium (NBRIP), which is more efficient than Pikovskaya medium (PVK), was developed for screening phosphate solubilizing microorganisms. In plate assay the efficiency of NBRIP was comparable to PVK; however, in broth assay NBRIP consistently demonstrated about 3-fold higher efficiency compared to PVK. The results indicated that the criterion for isolation of phosphate solubilizers based on the formation of visible halo/zone on agar plates is not a reliable technique, as many isolates which did not show any clear zone on agar plates solubilized insoluble inorganic phosphates in liquid medium. It may be concluded that soil microbes should be screened in NBRIP broth assay for the identification of the most efficient phosphate solubilizers. PMID:9919677

  16. Dynamic interplay between uranyl phosphate precipitation, sorption, and phase evolution

    SciTech Connect

    Munasinghe, P. Sumudu; Elwood Madden, Megan E.; Brooks, Scott C.; Elwood Madden, Andrew S.

    2015-04-17

    We report that natural examples demonstrate uranyl-phosphate minerals can maintain extremely low levels of aqueous uranium in groundwaters due to their low solubility. Thus, greater understanding of the geochemical factors leading to uranyl phosphate precipitation may lead to successful application of phosphate-based remediation methods. However, the solubility of uranyl phosphate phases varies over >3 orders of magnitude, with the most soluble phases typically observed in lab experiments. To understand the role of common soil/sediment mineral surfaces in the nucleation and transformation of uranyl phosphate minerals under environmentally relevant conditions, we carried out batch experiments with goethite and mica at pH 6 in mixed electrolyte solutions ranging from 1–800 μM U and 1–800 μM P. All experiments ended with uranium concentrations below the USEPA MCL for U, but with 2–3 orders of magnitude difference in uranium concentrations.

  17. Dynamic interplay between uranyl phosphate precipitation, sorption, and phase evolution

    DOE PAGESBeta

    Munasinghe, P. Sumudu; Elwood Madden, Megan E.; Brooks, Scott C.; Elwood Madden, Andrew S.

    2015-04-17

    We report that natural examples demonstrate uranyl-phosphate minerals can maintain extremely low levels of aqueous uranium in groundwaters due to their low solubility. Thus, greater understanding of the geochemical factors leading to uranyl phosphate precipitation may lead to successful application of phosphate-based remediation methods. However, the solubility of uranyl phosphate phases varies over >3 orders of magnitude, with the most soluble phases typically observed in lab experiments. To understand the role of common soil/sediment mineral surfaces in the nucleation and transformation of uranyl phosphate minerals under environmentally relevant conditions, we carried out batch experiments with goethite and mica at pHmore » 6 in mixed electrolyte solutions ranging from 1–800 μM U and 1–800 μM P. All experiments ended with uranium concentrations below the USEPA MCL for U, but with 2–3 orders of magnitude difference in uranium concentrations.« less

  18. Nitrate and phosphate removal by chitosan immobilized Scenedesmus.

    PubMed

    Fierro, Sashenka; Sánchez-Saavedra, Maria del Pilar; Copalcúa, Carmen

    2008-03-01

    The effect of chitosan immobilization of Scenedesmus spp. cells on its viability, growth and nitrate and phosphate uptake was investigated. Scenedesmus sp. (strains 1 and 2) and Scenedesmus obliquus immobilized in chitosan beads showed high viability after the immobilization process. Immobilized Scenedesmus sp. strain 1 had a higher growth rate than its free living counterpart. Nitrate and phosphate uptake by immobilized cells of Scenedesmus sp. (strain 1), freely suspended cells and blank chitosan beads (without cells) were evaluated. Immobilized cells accomplished a 70% nitrate and 94% phosphate removal within 12h of incubation while free-living cells removed 20% nitrate and 30% phosphate within 36 h of treatment. Blank chitosan beads were responsible for up to 20% nitrate and 60% phosphate uptake at the end of the experiment. Chitosan is a suitable matrix for immobilization of microalgae, particularly Scenedesmus sp., but this system should be improved before its application for water quality control.

  19. Determination of inorganic phosphate by electroanalytical methods: a review.

    PubMed

    Berchmans, Sheela; Issa, Touma B; Singh, Pritam

    2012-06-01

    Determination of inorganic phosphate is of very high importance in environmental and health care applications. Hence knowledge of suitable analytical techniques available for phosphate sensing for different applications becomes essential. Electrochemical methods for determining inorganic phosphate have several advantages over other common techniques, including detection selectivity, stability and relative environmental insensitivity of electroactive labels. The different electrochemical sensing strategies adopted for the determination of phosphate using selective ionophores are discussed in this review. The various sensing strategies are classified based on the electrochemical detection techniques used viz., potentiometry, voltammetry, amperometry, unconventional electrochemical methods etc., The enzymatic sensing of phosphate coupled with electrochemical detection is also included. Various electroanalytical methods available in the literature are assessed for their merits in terms of selectivity, simplicity, miniaturisation, adaptability and suitability for field measurements.

  20. Magnesium phosphate glass cements with ceramic-type properties

    SciTech Connect

    Sugama, T.; Kukacka, L.E.

    1984-03-13

    Rapid setting magnesium phosphate (Mg glass) cementitious materials consisting of magnesium phosphate cement paste, polyborax and water-saturated aggregate exhibiting rapid setting and high early strength characteristics. The magnesium glass cement is prepared from a cation-leachable powder and a bivalent metallic ion-accepting liquid such as an aqueous solution of diammonium phosphate and ammonium polyphosphate. The cation-leachable powder includes a mixture of two different magnesium oxide powders processed and sized differently which when mixed with the bivalent metallic ion-accepting liquid provides the magnesium glass cement consisting primarily of magnesium ortho phosphate tetrahydrate, with magnesium hydroxide and magnesium ammonium phosphate hexahydrate also present. The polyborax serves as a set-retarder. The resulting magnesium mono-and polyphosphate cements are particularly suitable for use as a cementing matrix in rapid repair systems for deteriorated concrete structures as well as construction materials and surface coatings for fireproof structures.

  1. Phosphate-stabilized Lithium intercalation compounds

    SciTech Connect

    Richardson, Thomas J.

    2002-07-22

    Four manganese and iron phosphates with alluaudite or fillowite structures have been prepared by solid state reactions: Na2FeMn2(PO4)3, LiNaFeMn2(PO4)3, NaFe3(PO4)3, and Na2Mn3(PO4)3. LixNa2-xFeMn2(PO4)3 with x close to 2 was prepared from Na2FeMn2(PO4)3 by molten salt ion exchange. These materials are similar in stoichiometry to the phospho-olivines LiFe(Mn)PO4, but have a more complex structure that can accommodate mixed transition metal oxidation states. They are of interest as candidates for lithium battery cathodes because of their somewhat higher electronic conductivity, high intercalant ion mobility, and ease of preparation. Their performance as intercalation electrodes in non-aqueous lithium cells was, however, poor.

  2. Dolichol and dolichyl phosphate in human tissues.

    PubMed Central

    Tollbom, O.; Dallner, G.

    1986-01-01

    The content of dolichol and dolichyl phosphate in various human organs was analysed using autopsy samples. The reliability of these measurements was demonstrated by comparison with values for fresh biopsy material. Dolichol was present in all tissues investigated and the content was highest in the adrenal gland, pancreas, pituitary gland, testis and thyroid gland, ranging between 1.5 and 7.1 mg/g tissue. Dolichyl-P was detected in the various organs in highly variable amounts, ranging between 1 and 9% of the total dolichol content. While the main pattern of isoprene composition for dolichol and dolichyl-P was similar in individual organs, some variation was observed between tissues. Dolichol represents the largest lipid component in the pituitary gland, exceeding the total phospholipid content. The high concentrations of dolichol and dolichyl-P in human organs indicate that these lipids may play important roles in physiological and pathological cellular functions. PMID:3641633

  3. The Pentose Phosphate Pathway in Parasitic Trypanosomatids.

    PubMed

    Kovářová, Julie; Barrett, Michael P

    2016-08-01

    Parasitic trypanosomatids cause important diseases. Dissecting the biochemistry of these organisms offers a means of discovering targets against which inhibitors may be designed and developed as drugs. The pentose phosphate pathway is a key route of glucose metabolism in most organisms, providing NADPH for use as a cellular reductant and various carbohydrate intermediates used in cellular metabolism. The pathway and its enzymes have been studied in Trypanosoma brucei, Trypanosoma cruzi, and various Leishmania species. Its functions in these parasites are becoming clear. Some enzymes of the pathway are essential to the parasites and have structural features distinguishing them from their mammalian counterparts, and this has stimulated several programs of inhibitor discovery with a view to targeting the pathway with new drugs.

  4. DKDP /potassium dideuterium phosphate/ light valves

    NASA Technical Reports Server (NTRS)

    Casasent, D.

    1977-01-01

    The use of potassium dideuterium phosphate (DKDP) light valves for optical data processing is discussed. The operating principles and structure of optically and electron beam addressed DKDPs are compared, and specifications for both devices given. Optically addressed DKDPs are capable of higher resolution and contrast, but both systems represent viable real time spatial light modulators adaptable to optical processing. Examples of real time data processing performed by the DKDPs include: image addition and subtraction; reduction of noise introduced by scattered light in recording media; reconstruction of computer generated and acoustic holograms; reconstruction of synthetic aperture radar data; retrieval of three-dimensional information in X-ray diagnoses; radar signal processing and display; and optical pattern recognition and correlation of images, which has applications for missile guidance systems.

  5. Methylerythritol Phosphate Pathway of Isoprenoid Biosynthesis

    PubMed Central

    Zhao, Lishan; Chang, Wei-chen; Xiao, Youli; Liu, Hung-wen; Liu, Pinghua

    2016-01-01

    Isoprenoids are a class of natural products with more than 50,000 members. All isoprenoids are constructed from two precursors, isopentenyl diphosphate (IPP) and its isomer dimethylallyl diphosphate (DMAPP). Two of the most important discoveries in isoprenoid biosynthetic studies in recent years are the elucidation of a second isoprenoid biosynthetic pathway (the methylerythritol phosphate (MEP) pathway) and a modified mevalonate (MVA) pathway. In this review, mechanistic insights on the MEP pathway enzymes are summarized. Since many isoprenoids have important biological activities, the need to produce them in sufficient quantities for downstream research efforts or commercial application is apparent. Recent advances in both the MVA and MEP pathway-based synthetic biology efforts are also illustrated by reviewing the landmark work of artemisinic acid and taxadien-5α-ol production through microbial fermentations. PMID:23746261

  6. Thermal Decomposition of Nitrated Tributyl Phosphate

    SciTech Connect

    Paddleford, D.F.; Hou, Y.; Barefield, E.K.; Tedder, D.W.; Abdel-Khalik, S.I.

    1995-01-01

    Contact between tributyl phosphate and aqueous solutions of nitric acid and/or heavy metal nitrate salts at elevated temperatures can lead to exothermic reactions of explosive violence. Even though such operations have been routinely performed safely for decades as an intrinsic part of the Purex separation processes, several so-called ``red oil`` explosions are known to have occurred in the United States, Canada, and the former Soviet Union. The most recent red oil explosion occurred at the Tomsk-7 separations facility in Siberia, in April 1993. That explosion destroyed part of the unreinforced masonry walls of the canyon-type building in which the process was housed, and allowed the release of a significant quantity of radioactive material.

  7. Controlling reaction specificity in pyridoxal phosphate enzymes

    PubMed Central

    Toney, Michael D.

    2012-01-01

    Pyridoxal 5'-phosphate enzymes are ubiquitous in the nitrogen metabolism of all organisms. They catalyze a wide variety of reactions including racemization, transamination, decarboxylation, elimination, retro-aldol cleavage, Claisen condensation, and others on substrates containing an amino group, most commonly α-amino acids. The wide variety of reactions catalyzed by PLP enzymes is enabled by the ability of the covalent aldimine intermediate formed between substrate and PLP to stabilize carbanionic intermediates at Cα of the substrate. This review attempts to summarize the mechanisms by which reaction specificity can be achieved in PLP enzymes by focusing on three aspects of these reactions: stereoelectronic effects, protonation state of the external aldimine intermediate, and interaction of the carbanionic intermediate with the protein side chains present in the active site. PMID:21664990

  8. Physicochemical equivalence of chloroquine phosphate tablets.

    PubMed

    Bamiro, O A; Odeniyi, M A; Idowu, O B; Jaiyeoba, K T

    2004-12-01

    Seven brands of chloroquine phosphate tablets sourced from different retail outlets in the South-West Nigerian market were analysed in order to determine their physicochemical equivalence. The assessment parameters included uniformity of weight, friability, crushing strength, disintegration and dissolution tests and chemical assay of the tablets. All the brands passed the British Pharmacopoeia tests for weight uniformity, disintegration time and dissolution rate. Two brands, C and E passed the minimum criterion for crushing strength, four brands passed the friability test and two brands exceeded the specified amount of active drug content for chloroquine tablets. Only one brand C out of the seven brands that were analysed passed all the BP quality specifications. Hence none of the seven brands analysed could said to be physically and chemically equivalent. This study highlights the need for constant market monitoring of new products in order to ascertain their quality. PMID:15977447

  9. Atomic-level characterization of transport cycle thermodynamics in the glycerol-3-phosphate:phosphate antiporter

    PubMed Central

    Moradi, Mahmoud; Enkavi, Giray; Tajkhorshid, Emad

    2015-01-01

    Membrane transporters actively translocate their substrate by undergoing large-scale structural transitions between inward- (IF) and outward-facing (OF) states (‘alternating-access' mechanism). Despite extensive structural studies, atomic-level mechanistic details of such structural transitions, and as importantly, their coupling to chemical events supplying the energy, remain amongst the most elusive aspects of the function of these proteins. Here we present a quantitative, atomic-level description of the functional thermodynamic cycle for the glycerol-3-phosphate:phosphate antiporter GlpT by using a novel approach in reconstructing the free energy landscape governing the IF↔OF transition along a cyclic transition pathway involving both apo and substrate-bound states. Our results provide a fully atomic description of the complete transport process, offering a structural model for the alternating-access mechanism and substantiating the close coupling between global structural transitions and local chemical events. PMID:26417850

  10. Phosphate microaggregates in Archean sediments. [Abstract only

    NASA Technical Reports Server (NTRS)

    Mojzsis, S.; Fan, G. Y.; Arrhenius, G.

    1994-01-01

    Light microscopy conducted on samples of Archean sediments reveals phosphate microaggregates which are suggestive of a biotic origin (Arrhenius et al., 1993). These aggregates, typically 15 micrometers wide and 50 micrometers long, are thought to be the mineral remains of colonies of microorganisms that lived during the late Archean Eon (greater than or equal to 2.5 Ga). Confocal microscopy was used to study the structures of these microaggregates in three dimensions. Samples used in this study are from the lowermost section of drill core taken from the Dales Gorge Member of the Brockman Iron-Formation (Hamersley Basin) in Western Australia. These sediments are well-preserved and escaped extensive metamorphism typically experienced by older rocks of this type. Two types of samples were prepared for study under the microscope: thin sections (30 micrometers) for transmitted light microscopy to study the general rock texture and to locate the grains of interest, and thick sections (3mm) for confocal microscopy to determine the 3-D structure of the aggregates in situ. The samples have been carefully polished so that they may be directly placed on the oil-immersion lens without the use of a cover slip. No chemical treatments of the surfaces have been performed. The aggregates often form clusters, although isolated aggregates have also been found. The clusters tend to distribute along microbands in the rocks. Electron microprobe analyses show that the phosphate grains and their inclusions, besides calcium and phosphorus, contain no major elements heavier than sodium. The proportions of calcium to phosphorus, the absence of stoichiometric amounts of other cations such as magnesium and iron, as well as optical properties suggest apatite as the mineral form.

  11. Renal Phosphate Wasting in the Absence of Adenylyl Cyclase 6

    PubMed Central

    Fenton, Robert A.; Murray, Fiona; Dominguez Rieg, Jessica A.; Tang, Tong; Levi, Moshe

    2014-01-01

    Parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF-23) enhance phosphate excretion by the proximal tubule of the kidney by retrieval of the sodium-dependent phosphate transporters (Npt2a and Npt2c) from the apical plasma membrane. PTH activates adenylyl cyclase (AC) through PTH 1 receptors and stimulates the cAMP/PKA signaling pathway. However, the precise role and isoform(s) of AC in phosphate homeostasis are not known. We report here that mice lacking AC6 (AC6−/−) have increased plasma PTH and FGF-23 levels compared with wild-type (WT) mice but comparable plasma phosphate concentrations. Acute activation of the calcium-sensing receptor or feeding a zero phosphate diet almost completely suppressed plasma PTH levels in both AC6−/− and WT mice, indicating a secondary cause for hyperparathyroidism. Pharmacologic blockade of FGF receptors resulted in a comparable increase in plasma phosphate between genotypes, whereas urinary phosphate remained significantly higher in AC6−/− mice. Compared with WT mice, AC6−/− mice had reduced renal Npt2a and Npt2c protein abundance, with approximately 80% of Npt2a residing in lysosomes. WT mice responded to exogenous PTH with redistribution of Npt2a from proximal tubule microvilli to intracellular compartments and lysosomes alongside a PTH-induced dose–response relationship for fractional phosphate excretion and urinary cAMP excretion. These responses were absent in AC6−/− mice. In conclusion, AC6 in the proximal tubule modulates cAMP formation, Npt2a trafficking, and urinary phosphate excretion, which are highlighted by renal phosphate wasting in AC6−/− mice. PMID:24854272

  12. Proteinuria Increases Plasma Phosphate by Altering Its Tubular Handling

    PubMed Central

    Courbebaisse, Marie; Rutkowski, Joseph M.; Wilhelm-Bals, Alexandra; Metzger, Marie; Khodo, Stellor Nlandu; Hasler, Udo; Chehade, Hassib; Dizin, Eva; Daryadel, Arezoo; Stengel, Bénedicte; Girardin, E.; Prié, Dominique; Wagner, Carsten A.; Scherer, Philipp E.; Martin, Pierre-Yves; Houillier, Pascal; Feraille, Eric

    2015-01-01

    Proteinuria and hyperphosphatemia are cardiovascular risk factors independent of GFR. We hypothesized that proteinuria induces relative phosphate retention via increased proximal tubule phosphate reabsorption. To test the clinical relevance of this hypothesis, we studied phosphate handling in nephrotic children and patients with CKD. Plasma fibroblast growth factor 23 (FGF-23) concentration, plasma phosphate concentration, and tubular reabsorption of phosphate increased during the proteinuric phase compared with the remission phase in nephrotic children. Cross-sectional analysis of a cohort of 1738 patients with CKD showed that albuminuria≥300 mg/24 hours is predictive of higher phosphate levels, independent of GFR and other confounding factors. Albuminuric patients also displayed higher plasma FGF-23 and parathyroid hormone levels. To understand the molecular mechanisms underlying these observations, we induced glomerular proteinuria in two animal models. Rats with puromycin-aminonucleoside–induced nephrotic proteinuria displayed higher renal protein expression of the sodium-phosphate co-transporter NaPi-IIa, lower renal Klotho protein expression, and decreased phosphorylation of FGF receptor substrate 2α, a major FGF-23 receptor substrate. These findings were confirmed in transgenic mice that develop nephrotic-range proteinuria resulting from podocyte depletion. In vitro, albumin did not directly alter phosphate uptake in cultured proximal tubule OK cells. In conclusion, we show that proteinuria increases plasma phosphate concentration independent of GFR. This effect relies on increased proximal tubule NaPi-IIa expression secondary to decreased FGF-23 biologic activity. Proteinuria induces elevation of both plasma phosphate and FGF-23 concentrations, potentially contributing to cardiovascular disease. PMID:25349200

  13. Crystal structure of the phosphate-binding protein (PBP-1) of an ABC-type phosphate transporter from Clostridium perfringens.

    PubMed

    Gonzalez, Daniel; Richez, Magali; Bergonzi, Celine; Chabriere, Eric; Elias, Mikael

    2014-01-01

    Phosphate limitation is an important environmental stress that affects the metabolism of various organisms and, in particular, can trigger the virulence of numerous bacterial pathogens. Clostridium perfringens, a human pathogen, is one of the most common causes of enteritis necroticans, gas gangrene and food poisoning. Here, we focused on the high affinity phosphate-binding protein (PBP-1) of an ABC-type transporter, responsible for cellular phosphate uptake. We report the crystal structure (1.65 Å resolution) of the protein in complex with phosphate. Interestingly, PBP-1 does not form the short, low-barrier hydrogen bond with phosphate that is typical of previously characterized phosphate-binding proteins, but rather a canonical hydrogen bond. In its unique binding configuration, PBP-1 forms an unusually high number of hydrogen bonds (14) with the phosphate anion. Discrimination experiments reveal that PBP-1 is the least selective PBP characterised so far and is able to discriminate phosphate from its close competing anion, arsenate, by ~150-fold.

  14. Crystal structure of the phosphate-binding protein (PBP-1) of an ABC-type phosphate transporter from Clostridium perfringens.

    PubMed

    Gonzalez, Daniel; Richez, Magali; Bergonzi, Celine; Chabriere, Eric; Elias, Mikael

    2014-01-01

    Phosphate limitation is an important environmental stress that affects the metabolism of various organisms and, in particular, can trigger the virulence of numerous bacterial pathogens. Clostridium perfringens, a human pathogen, is one of the most common causes of enteritis necroticans, gas gangrene and food poisoning. Here, we focused on the high affinity phosphate-binding protein (PBP-1) of an ABC-type transporter, responsible for cellular phosphate uptake. We report the crystal structure (1.65 Å resolution) of the protein in complex with phosphate. Interestingly, PBP-1 does not form the short, low-barrier hydrogen bond with phosphate that is typical of previously characterized phosphate-binding proteins, but rather a canonical hydrogen bond. In its unique binding configuration, PBP-1 forms an unusually high number of hydrogen bonds (14) with the phosphate anion. Discrimination experiments reveal that PBP-1 is the least selective PBP characterised so far and is able to discriminate phosphate from its close competing anion, arsenate, by ~150-fold. PMID:25338617

  15. UV-visible and infrared absorption spectra of gamma irradiated CuO-doped lithium phosphate, lead phosphate and zinc phosphate glasses: A comparative study

    NASA Astrophysics Data System (ADS)

    ElBatal, H. A.; Abdelghany, A. M.; ElBatal, F. H.; ElBadry, Kh. M.; Moustaffa, F. A.

    2011-10-01

    Undoped and CuO-doped lithium phosphate, lead phosphate and zinc phosphate glasses were prepared. UV-visible and infrared absorption spectra of the prepared samples were measured before and after successive gamma irradiation. Experimental optical spectra of the undoped samples reveal strong UV absorption bands, which are attributed to the presence of trace iron impurities in both the lithium and zinc phosphate glasses while the lead phosphate glass exhibits broad UV bands due to combined absorption of trace iron impurities and divalent lead ions. The CuO-doped glasses reveal an extra broad visible band due to Cu 2+ ions in octahedral coordination. The effects of gamma irradiation have been analyzed for both the sharing of all constituent components including trace iron impurities. Infrared absorption spectra of the prepared samples were investigated by the KBr disk technique. The FTIR spectra reveal main characteristic absorption bands due to different phosphate groups. The IR spectra are observed to be slightly affected by the increase of CuO in the doping level (0.2-3%) indicating the stability of the main network units.

  16. Chemisorption of phosphate ions and destruction of organomineral sorbents in acid soils

    NASA Astrophysics Data System (ADS)

    Kudeyarova, A. Yu.

    2010-06-01

    The chemisorption mechanisms of phosphate anions by iron (aluminum) containing sorbents in a soil under high phosphate loads were studied. The role of the metal-phosphate anions in the destruction of the sorbents was discussed. It was shown that the chemisorption of phosphate anions and the destruction of phosphated organomineral sorbents are interrelated processes. A significant part of the chemisorbed phosphates in association with sorbent metals and carbon passes into the liquid phase of soil systems.

  17. Metal sulfide and rare-earth phosphate nanostructures and methods of making same

    DOEpatents

    Wong, Stanislaus; Zhang, Fen

    2016-06-28

    The present invention provides a method of producing a crystalline rare earth phosphate nanostructure. The method comprising: providing a rare earth metal precursor solution and providing a phosphate precursor solution; placing a porous membrane between the metal precursor solution and the phosphate precursor solution, wherein metal cations of the metal precursor solution and phosphate ions of the phosphate precursor solution react, thereby producing a crystalline rare earth metal phosphate nanostructure.

  18. Osteoregenerative capacities of dicalcium phosphate-rich calcium phosphate bone cement.

    PubMed

    Ko, Chia-Ling; Chen, Jian-Chih; Tien, Yin-Chun; Hung, Chun-Cheng; Wang, Jen-Chyan; Chen, Wen-Cheng

    2015-01-01

    Calcium phosphate cement (CPC) is a widely used bone substitute. However, CPC application is limited by poor bioresorption, which is attributed to apatite, the stable product. This study aims to systematically survey the biological performance of dicalcium phosphate (DCP)-rich CPC. DCP-rich CPC exhibited a twofold, surface-modified DCP anhydrous (DCPA)-to-tetracalcium phosphate (TTCP) molar ratio, whereas conventional CPC (c-CPC) showed a onefold, surface unmodified DCPA-to-TTCP molar ratio. Cell adhesion, morphology, viability, and alkaline phosphatase (ALP) activity in the two CPCs were examined with bone cell progenitor D1 cultured in vitro. Microcomputed tomography and histological observation were conducted after CPC implantation in vivo to analyze the residual implant ratio and new bone formation rate. D1 cells cultured on DCP-rich CPC surfaces exhibited higher cell viability, ALP activity, and ALP quantity than c-CPC. Histological evaluation indicated that DCP-rich CPC showed lesser residual implant and higher new bone formation rate than c-CPC. Therefore, DCP-rich CPC can improve bioresorption. The newly developed DCP-rich CPC exhibited potential therapeutic applications for bone reconstruction.

  19. Role of phosphate solubilizing bacteria on rock phosphate solubility and growth of aerobic rice.

    PubMed

    Panhwar, Q A; Radziah, O; Zaharah, A R; Sariah, M; Razi, I Mohd

    2011-09-01

    Use of phosphate-solubilizing bacteria (PSB) as inoculants has concurrently increased phosphorous uptake in plants and improved yields in several crop species. The ability of PSB to improve growth of aerobic rice (Oryza sativa L.) through enhanced phosphorus (P) uptake from Christmas island rock phosphate (RP) was studied in glasshouse experiments. Two isolated PSB strains; Bacillus spp. PSB9 and PSB16, were evaluated with RP treatments at 0, 30 and 60 kg ha(-1). Surface sterilized seeds of aerobic rice were planted in plastic pots containing 3 kg soil and the effect of treatments incorporated at planting were observed over 60 days of growth. The isolated PSB strains (PSB9 and PSB16) solubilized significantly high amounts of P (20.05-24.08 mg kg(-1)) compared to non-inoculated (19-23.10 mg kg(-1)) treatments. Significantly higher P solubilization (24.08 mg kg(-1)) and plant P uptake (5.31 mg plant(-1)) was observed with the PSB16 strain at the highest P level of 60 kg ha(-1). The higher amounts of soluble P in the soil solution increased P uptake in plants and resulted in higher plant biomass (21.48 g plant(-1)). PSB strains also increased plant height (80 cm) and improved root morphology in aerobic rice. The results showed that inoculation of aerobic rice with PSB improved phosphate solubilizing activity of incorporated RP.

  20. Intermediate-range order in simple metal-phosphate glasses: The effect of metal cations on the phosphate anion distribution

    SciTech Connect

    Sales, B.C.; Boatner, L.A.; Ramey, J.O.

    1997-06-01

    The technique of high-performance liquid chromatography (HPLC) has been used to probe the phosphate anion distribution in a variety of metal phosphate glasses including glasses made with trivalent metal cations (Al, In, Ga, La). The composition of each glass was chosen so that the average phosphate chain length was between 2 and 4 PO{sub 4} tetrahedra. The widths of the resulting phosphate anion distributions were determined directly from an analysis of the HPLC chromatograms. Literature values for the free energy of formation of the crystalline metal-orthophosphate compounds with respect to P{sub 2}O{sub 5} and the metal oxide, were compared to the chromatogram widths. It was found that the smaller the energy of formation, the wider the distribution of phosphate chains, and the greater the ease of glass formation.