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Sample records for apatites

  1. Polysomatic apatites

    Energy Technology Data Exchange (ETDEWEB)

    Baikie, Tom; Pramana, Stevin S.; Huang, Yizhong; Ahmad, Zahara [Nanyang Technological Univ., Singapore (Singapore). Div. of Materials Science and Engineering; Ferraris, Cristiano [Museum National d' Histoire Naturelle, UMR-CNRS, 75 - Paris (France). Lab. de Mineralogie et Cosmochimie; Kendrick, Emma [Surrey Univ., Guildford (United Kingdom). Chemical Sciences; Knight, Kevin S. [Appleton Lab., Chilton, Didcot (United Kingdom). ISIS User Office; White, T.J. [Nanyang Technological Univ., Singapore (Singapore). Div. of Materials Science and Engineering; Australian National Univ., Canberra, ACT (Australia). Centre for Advanced Microscopy

    2010-02-15

    Certain complex structures are logically regarded as intergrowths of chemically or topologically discrete modules.When the proportions of these components vary systematically a polysomatic series is created, whose construction provides a basis for understanding defects, symmetry alternation and trends in physical properties. Here, we describe the polysomatic family A{sub 5N}B{sub 3N}O{sub 9N+6}X{sub N{delta}} (2{<=}N{<=}{infinity}) that is built by condensing N apatite modules (A{sub 5}B{sub 3}O{sub 18}X{sub {delta}}) in configurations to create B{sub n}O{sub 3n+1} (1{<=}n{<=}{infinity}) tetrahedral chains. Hydroxyapatite [Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}] typifies a widely studied polysome where N=2 and the tetrahedra are isolated in A{sub 10}(BO{sub 4}){sub 6}X{sub 2} compounds, but N=3 A{sub 15}(B{sub 2}O{sub 7}){sub 3}(BO{sub 4}){sub 3}X{sub 3} (ganomalite) and N=4 A{sub 20}(B{sub 2}O{sub 7}){sub 6}X{sub 4} (nasonite) are also known, with the X site untenanted or partially occupied as required for charge balance. The apatite modules, while topologically identical, are often compositionally or symmetrically distinct, and an infinite number of polysomes is feasible, generally with the restriction being that an A:B = 5:3 cation ratio be maintained. The end-members are the N=2 polysome with all tetrahedra separated, and N={infinity}, in which the hypothetical compound A{sub 5}B{sub 3}O{sub 9}X contains infinite, cornerconnected tetrahedral strings. The principal characteristics of a polysome are summarized using the nomenclature apatite- (A B X)-NS, where A/B/X are the most abundant species in these sites, N is the number of modules in the crystallographic repeat, and S is the symmetry symbol (usually H, T, M or A). This article examines the state-of-the-art in polysomatic apatite synthesis and crystallochemical design. It also presents X-ray and neutron powder diffraction investigations for several polysome chemical series and examines the prevalence of

  2. Hanford Apatite Treatability Test Report Errata: Apatite Mass Loading Calculation

    Energy Technology Data Exchange (ETDEWEB)

    Szecsody, James E.; Vermeul, Vincent R.; Williams, Mark D.; Truex, Michael J.

    2014-05-19

    The objective of this errata report is to document an error in the apatite loading (i.e., treatment capacity) estimate reported in previous apatite treatability test reports and provide additional calculation details for estimating apatite loading and barrier longevity. The apatite treatability test final report (PNNL-19572; Vermeul et al. 2010) documents the results of the first field-scale evaluation of the injectable apatite PRB technology. The apatite loading value in units of milligram-apatite per gram-sediment is incorrect in this and some other previous reports. The apatite loading in units of milligram phosphate per gram-sediment, however, is correct, and this is the unit used for comparison to field core sample measurements.

  3. Dikes and mineralization in uraniferous apatite deposits

    International Nuclear Information System (INIS)

    The problem of the age relationships between dike bodies and the mineralization in deposits of uraniferous apatites in carbonate rocks is reconsidered. The post-ore history of apatite mineralization reveals a combination of polygenic mineral associations

  4. Stable carbon isotope analysis of bone apatite

    International Nuclear Information System (INIS)

    The application of stable carbon isotope analysis to bone apatite is investigated. Bone apatite was prepared from 28 samples of 5 species of modern browsing herbivores, and their 13C/12C ratios measured. The δ13C values for bone apatite of the modern specimens shows a mean enrichment of +12 o/oo relative to the C3 dietary mean of -26.5o/oo. The values for T. strepsiceros (kudu) suggest that it is not a consistent browzer, as was formerly believed. Seven fossil bone apatite browzer samples gave δ13C values which fell within the range for the modern samples. It is concluded that the 13C/12C ratio in modern bone apatite accurately reflects diet, but data for fossil samples was insufficient to allow a firm conclusion about the reliability of bone apatite dietary tracing in archaeological contexts

  5. Radiation effects in zircon and apatite

    International Nuclear Information System (INIS)

    Zircon and apatite form as actinide host phases in several high-level waste forms and have been proposed as host phases for the immobilization of plutonium and other actinides. Self-radiation damage from α-decay of the incorporated Pu (or other actinides) can affect the durability and performance of these actinide-bearing phases. Natural zircons and apatites, with ages up to 4 billion years, provide abundant evidence for their long-term durability because of their wide spread use in geochronology and fission-track dating. Detailed studies of natural zircons and apatites, 238Pu-containing zircon, a 244Cm-containing silicate apatite, and ion-irradiated zircon, natural apatite, and synthetic silicate apatites provide a unique basis for the analysis of α-decay effects over broad time scales. Recent results of some of these studies are presented here

  6. Bioactivity of mica/apatite glass ceramics

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The bioactivity of mica/apatite glass ceramic composites, including the in vitro behavior in simulated body fluid and the histological appearance of the interface between the mica/apatite glass ceramics and the rabbit mandible defect in vivo under a dynamic condition. The results show that biological apatite layer forms on the surface of the mica/apatite glass ceramics after 1 d of immersion in the simulated body fluid, and becomes dense after 14 d. In vivo tests indicate that bone formation occurs after implantation for 14 d, and strong bonding of bone to the implant occurs after 42 d. No aseptic loosening occurs during 42 d of implantation. The finding shows that mica/apatite glass ceramics have good bioactivity and osteoconductivity for constructing bone graft, and can be promising for biomedical application.

  7. U-Pb Ages of Lunar Apatites

    Science.gov (United States)

    Vaughan, J.; Nemchin, A. A.; Pidgeon, R. T.; Meyer, Charles

    2006-01-01

    Apatite is one of the minerals that is rarely utilized in U-Pb geochronology, compared to some other U-rich accessory phases. Relatively low U concentration, commonly high proportion of common Pb and low closure temperature of U-Pb system of apatite inhibit its application as geochronological tool when other minerals such as zircon are widely available. However, zircon appear to be restricted to certain type of lunar rocks, carrying so called KREEP signature, whereas apatite (and whitlockite) is a common accessory mineral in the lunar samples. Therefore, utilizing apatite for lunar chronology may increase the pool of rocks that are available for U-Pb dating. The low stability of U-Pb systematics of apatite may also result in the resetting of the system during meteoritic bombardment, in which case apatite may provide an additional tool for the study of the impact history of the Moon. In order to investigate these possibilities, we have analysed apatites and zircons from two breccia samples collected during the Apollo 14 mission. Both samples were collected within the Fra Mauro formation, which is interpreted as a material ejected during the impact that formed the Imbrium Basin.

  8. Apatite-Melt Partitioning at 1 Bar: An Assessment of Apatite-Melt Exchange Equilibria Resulting from Non-Ideal Mixing of F and Cl in Apatite

    Science.gov (United States)

    McCubbin, F. M.; Ustunisik, G.; Vander Kaaden, K. E.

    2016-01-01

    The mineral apatite [Ca5(PO4)3(F,Cl,OH)] is present in a wide range of planetary materials. Due to the presence of volatiles within its crystal structure (X-site), many recent studies have attempted to use apatite to constrain the volatile contents of planetary magmas and mantle sources. In order to use the volatile contents of apatite to precisely determine the abundances of volatiles in coexisting silicate melt or fluids, thermodynamic models for the apatite solid solution and for the apatite components in multi-component silicate melts and fluids are required. Although some thermodynamic models for apatite have been developed, they are incomplete. Furthermore, no mixing model is available for all of the apatite components in silicate melts or fluids, especially for F and Cl components. Several experimental studies have investigated the apatite-melt and apatite-fluid partitioning behavior of F, Cl, and OH in terrestrial and planetary systems, which have determined that apatite-melt partitioning of volatiles are best described as exchange equilibria similar to Fe-Mg partitioning between olivine and silicate melt. However, McCubbin et al. recently reported that the exchange coefficients may vary in portions of apatite compositional space where F, Cl, and OH do not mix ideally in apatite. In particular, solution calorimetry data of apatite compositions along the F-Cl join exhibit substantial excess enthalpies of mixing. In the present study, we conducted apatite-melt partitioning experiments in evacuated, sealed silica-glass tubes at approximately 1 bar and 950-1050 degrees Centigrade on a synthetic Martian basalt composition equivalent to the basaltic shergottite Queen Alexandria Range (QUE) 94201. These experiments were conducted dry, at low pressure, to assess the effects of temperature and apatite composition on the partitioning behavior of F and Cl between apatite and basaltic melt along the F-Cl apatite binary join, where there is non-ideal mixing of F and Cl

  9. Preparation, characterization and in vitro evaluation of nanostructured chitosan/apatite and chitosan/Si-doped apatite composites

    OpenAIRE

    Solis, Yaimara; Davidenko, Natalia; Carrodeguas, Raul G.; Cruz, Jeny; Hernandez, Andy; Tomas, Miriela; Cameron, Ruth Elizabeth; Peniche, Carlos

    2013-01-01

    Chitosan/apatite composites are attracting great attention as biomaterials for bone repair and regeneration procedures. The reason is their unique set of properties: bioactivity and osteoconductivity provided by apatite and resorbability supplied by chitosan among others. Thus, in this work chitosan/apatite and chitosan/Si-doped apatite composites were prepared and characterized. Particle size, surface area, in vitro physiological stability, enzymatic biodegradation and bioactivity were evalu...

  10. Sulfur evolution of the 1991 Pinatubo magmas based on apatite

    Science.gov (United States)

    Van Hoose, Ashley E.; Streck, Martin J.; Pallister, John S.; Wälle, Markus

    2013-05-01

    Using electron microprobe (EMP) and laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to collect major and rare-earth elements (REE), respectively, from apatites from the 1991 Mt. Pinatubo juvenile eruption products, we have determined that two statistically distinct populations of apatite exist. One population crystallized from the juvenile basaltic melt (basalt apatites) and the other population crystallized from the main dacitic magma body (silicic apatites). Both populations contain high-S apatites (> 0.7 wt.% SO3). Apatite has previously been shown to be a potential monitor for magmatic sulfur contents via numerous proposed coupled substitutions of P5 + for S6 +. However, simple apatite/melt partitioning cannot account for high-S silicic apatites, which grew from a silicic melt with an apparent maximum S concentration of ~ 80 ppm. Disparate apatite morphology (i.e. skeletal and acicular for basalt apatites and euhedral for silicic apatites) as well as compositional evidence reveal that high-S silicic apatites were not inherited from the juvenile basalt during mingling/mixing prior to eruption. Sulfur gain from neighboring anhydrite phenocrysts can also be ruled-out as a source of high sulfur. EMP sulfur mapping of silicic apatites shows highly irregular patterns of sulfur enrichment that do not correspond with adjacent anhydrite and can be found within apatites hosted by other minerals (e.g. hornblende and Fe-Ti oxides). With these data in mind, we propose high-S silicic apatites from Pinatubo and other sulfur-rich systems achieved elevated sulfur concentrations during high sulfur fluxing events that originated from underplated basalt during degassing of a SO2-rich fluid phase. That basalts were indeed sulfur rich and oxidized is here indicated by high S contents of apatites growing in basalt. The predominant location of S-rich areas of silicic apatite is crystal interiors of apatite inclusions in other mineral phases, while large apatite

  11. Immobilizing hydroxycholesterol with apatite on titanium surfaces to induce ossification

    OpenAIRE

    Chen, Cen; Yang, Hyeong Cheol; Lee, In-Seop

    2014-01-01

    Background Immobilizing bioactive molecules and osteoconductive apatite on titanium implants have investigated direct ossification. In this study, hydroxycholesterol (HC) was immobilized with apatite on titanium through simply adsorption or sandwich-like coating. Three kinds of hydroxycholesterol were chosen to induce ossification: 20α-hydroxycholesterol (20α- HC), 22(S)-hydroxycholesterol (22(S)-HC) and 25-hydroxycholesterol (25-HC).The effects of HC/apatite coating on ossification abilities...

  12. Reactive backfills in radioactive waste disposal selenium sorption on apatite

    International Nuclear Information System (INIS)

    Apatites are investigated as possible high performance material for reactive backfills in radioactive waste disposal. An experimental study showed an excellent selenite retaining rate and established the main characteristic of this element sorption on natural and synthetic apatites. Thermodynamical parameters have been calculated and integrated in a geochemical computer code in order to demonstrate the excellent potentialities of the apatite as a trap mineral for the selenium. (A.L.B.)

  13. Chitosan/apatite composite beads prepared by in situ generation of apatite or Si-apatite nanocrystals.

    Science.gov (United States)

    Davidenko, Natalia; Carrodeguas, Raúl G; Peniche, Carlos; Solís, Yaimara; Cameron, Ruth E

    2010-02-01

    The objective of this work was to develop nanocrystalline apatite (Ap) dispersed in a chitosan (CHI) matrix as a material for applications in bone tissue engineering. CHI/Ap composites of different weight ratios (20/80, 50/50 and 80/20) and with CHI of different molecular weights were prepared by a biomimetic stepwise route. Firstly, CaHPO(4).2H(2)O (DCPD) crystals were precipitated from Ca(CH(3)COO)(2) and NaHPO(4) in the bulk CHI solution, followed by the formation of CHI/DCPD beads by coacervation. The beads were treated with Na(3)PO(4)/Na(5)P(3)O(10) solution (pH 12-13) to crosslink the CHI and to hydrolyse the DCPD to nanocrystalline Ap. This new experimental procedure ensured that complete conversion of DCPD into sodium-substituted apatite was achieved without appreciable increases in its crystallinity and particle size. In addition, composites with silicon-doped Ap were prepared by substituting Na(3)PO(4) by Na(2)SiO(3) in the crosslinking/hydrolysis step. Characterization of the resultant composites by scanning electron microscopy, X-ray powder diffraction (XRD), thermal analysis and Fourier transform infrared spectroscopy confirmed the formation, within the CHI matrix, of nanoparticles of sodium- and carbonate-substituted hydroxyapatite [Ca(10-x)Na(x)(PO(4))(6-x)(CO(3))(x)(OH)(2)] with diameters less than 20nm. Relatively good correspondence was shown between the experimentally determined inorganic content and that expected theoretically. Structural data obtained from its XRD patterns revealed a decrease in both crystal domain size and cell parameters of Ap formed in situ with increasing CHI content. It was found that the molecular weight of CHI and silicate doping both affected the nucleation and growth of apatite nanocrystallites. These effects are discussed in detail. PMID:19632363

  14. RBS and RNRA studies on sorption of europium by apatite

    Energy Technology Data Exchange (ETDEWEB)

    Ohnuki, Toshihiko; Kozai, Naofumi; Isobe, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Murakami, Takashi; Yamamoto, Shunya; Aoki, Yasushi; Naramoto, Hiroshi

    1997-03-01

    The sorption mechanism of europium, alternative of trivalent TRU has been studied based on the depth profiles of elements obtained by Rutherford Backscattering Spectroscopy (RBS) and Resonant Nuclear Reaction Analysis (RNRA). The positive peak for Eu and the negative peak for Ca were observed in the subtracted RBS spectra of the apatites on which Eu was sorbed from that of the fresh apatite. This indicates that Eu was sorbed on apatite, while a fraction of Ca was released from apatite. The peak height for Eu in the RBS spectrum of the apatite obtained at 75degC was higher than that of the apatite at 40degC. The depth profile of hydrogen of the apatite on which Eu was sorbed was similar to that of the fresh apatite. The concentration of Eu in the solution decreased with increasing temperature. On the contrary, the concentration of Ca increased with increasing temperature. Thus, it is concluded that a fraction of Eu is exchanged for Ca in the structure of apatite. (author)

  15. Geochemistry of Apatite from the Apatite-rich Iron Deposits in the Ningwu Region, East Central China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Four types of apatite have been identified in the Ningwu region. The first type of apatite is widely distributed in the middle dark colored zones (i.e. iron ores) of individual deposits. The assemblage includes magnetite, apatite and actinolite (or diopside). The second type occurs within magnetite-apatite veins in the iron ores. The third type is seen in magnetite-apatite veins and (or)nodules in host rocks (i.e. gabbro-diorite porphyry or gabbro-diorite or pyroxene diorite).The fourth type occurs within apatite-pyrite-quartz veins filling fractures in the Xiangshan Group. Rare earth elements (REE) geochemistry of apatite of the four occurrences in porphyry iron deposits is presented. The REE distribution patterns of apatite are generally similar to those of apatites in the Kiruna-type iron ores, nelsonites. They are enriched in light REE, with pronounced negative Eu anomalies. The similarity of REE distribution patterns in apatites from various deposits in different locations in the world indicates a common process of formation for various ore types, e.g.immiscibility. Early magmatic apatites contain 3031.48-12080 ×10-6 REE. Later hydrothermal apatite contains 1958 ×10-6 REE, indicating that the later hydrothermai ore-forming solution contains lower REE. Although gabbro-diorite porphyry and apatite show similar REE patterns, gabbro-diorite porphyries have no europium anomalies or feeble positive or feeble negative europium anomalies,caused both by reduction environment of mantle source region and by fractionation and crystallization (immiscibility) under a high oxygen fugacity condition. Negative Eu anomalies of apatites were formed possibly due to acquisition of Eu2+ by earlier diopsite during ore magma cooling.The apatites in the Aoshan and Taishan iron deposits yield a narrow variation range of 87Sr/86Sr values from 0.7071 to 0.7073, similar to those of the volcanic and subvoicanic rocks, indicating that apatites were formed by liquid immiscibility and

  16. Carbon isotope analysis of fossil bone apatite

    International Nuclear Information System (INIS)

    The feasibility of using bone apatite for stable carbon isotope analysis of ancient bone for palaeodietary studies has been the subject of much controversy, and attempts to determine whether isotopic signatures are stable over time have produced contradictory results. We have tested this stability by measuring the δ13C values of chemically treated bone or tooth mineral of herbivores of known diet (browsers), in a temporal series. The results indicate that diagenesis of biogenic carbonates in the mineral over time is unexpectedly limited, and that chemical pretreatment further reduces diagenetic alteration of the biogenic signal. Enough biogenic carbonate remains to distinguish clearly between browsers and grazers, even after 3 million years

  17. Rare earth elements materials production from apatite ores

    Science.gov (United States)

    Anufrieva, A. V.; Andrienko, O. S.; Buynovskiy, A. S.; Makaseev, Y. N.; Mazov, I. N.; Nefedov, R. A.; Sachkov, V. I.; Stepanova, O. B.; Valkov, A. V.

    2016-01-01

    The paper deals with the study of processing apatite ores with nitric acid and extraction of the rare earth elements. The rare earth elements can be successfully separated and recovered by extraction from the nitrate- phosphate solution, being an tributyl phosphate as extraction agent. The developed scheme of the processing apatite concentrate provides obtaining rare earth concentrates with high qualitative characteristics.

  18. From natural to synthetic apatites: the use of apatites as conditioning material for separated nuclear wastes

    International Nuclear Information System (INIS)

    The minerals with an apatite structure formed two billion years ago during natural nuclear reactions in Oklo (Gabon) are phospho-silicate apatites called britholites. In the lattice, they contain as substitutions or inclusions radioactive elements or the fission products. They remain totally stable and appear to be excellent to be excellent nuclear waste conditioning materials. From these observations, the study of synthetics britholites was carried out. The optimal chemical composition was determined, solid/solid synthesis was performed and the stability under radioactive, thermal conditions was studied in relation to geological observations. The first results indicating resistance to radiation and leaching open a supplementary way for the preparation of conditioning material for separated nuclear waste. (authors)

  19. Development of Tributyl Phosphate Apatite for Uranium Removal

    International Nuclear Information System (INIS)

    The FTIR results showed that main peaks were shown at 3570 cm-1 in all materials. The band around at 3570 cm-1 indicates the stretching hydroxyl group from HA. Phosphate functional group was observed around at 1040 cm-1. The C-H containing functional group (3000-2950 cm-1) was found only in the TBP-apatite prepared at pH=10 condition. Uranium removal was evaluated under different reaction times, initial U concentrations, and background solution using synthesized HA and TBP-apatite. As NaHCO3 concentration increased, U removal decreased. In the same condition, TBP-apatite showed better U removal than HA, which indicates TBP-apatite can be used as U removal sorbent

  20. Development of Tributyl Phosphate Apatite for Uranium Removal

    Energy Technology Data Exchange (ETDEWEB)

    Kim, HyunJu; Kang, Jaehyuk; Kim, Jungjin; Uma, Wooyong [POSTECH, Daejeon (Korea, Republic of)

    2015-05-15

    The FTIR results showed that main peaks were shown at 3570 cm-1 in all materials. The band around at 3570 cm-1 indicates the stretching hydroxyl group from HA. Phosphate functional group was observed around at 1040 cm-1. The C-H containing functional group (3000-2950 cm-1) was found only in the TBP-apatite prepared at pH=10 condition. Uranium removal was evaluated under different reaction times, initial U concentrations, and background solution using synthesized HA and TBP-apatite. As NaHCO{sub 3} concentration increased, U removal decreased. In the same condition, TBP-apatite showed better U removal than HA, which indicates TBP-apatite can be used as U removal sorbent.

  1. EPR dosimetry with synthetic A-type carbonated apatite

    International Nuclear Information System (INIS)

    Synthetic A-type carbonated apatite prepared in reproducible conditions were irradiated at room temperature with 60 Co γ rays. The EPR spectrum is associated to axial CO2- and orthorhombic CO3- species. Radicals used as dose marker in biological apatite are long live paramagnetic species. The stability of the post-irradiation signal of A-type apatite was investigated for more than one year. Measurements showed variations in the spectra attributed to unstable CO3- species, which can be eliminated by thermal treatments at 100 deg C for 24 hours. The CO2- spectrum can be identified in samples irradiated up to 0.2 Gy. All results indicate the A-type apatite as an appropriate material for radiotherapy dosimetry. (author)

  2. On the fractal nature of carbonate and apatite rocks

    International Nuclear Information System (INIS)

    Small angle neutron scattering experiments were performed to investigate the porous structure of the basic components of the apatite-carbonate ores. It is shown that the surfaces of carbonate mineral grains taken from various sorts of ores are the Euclidean fractals with fractal dimensions 2< D < or approx. 2.25. Preliminary results for apatites show their more developed fractal porosity. 19 refs.; 4 figs.; 1 tab

  3. Biomimetic Fabrication of Hydroxyapatite Microcapsules by Using Apatite Nuclei

    OpenAIRE

    Yao, Takeshi; Yabutsuka, Takeshi

    2010-01-01

    When the pH or the temperature of SBF is raised, fine particles of calcium phosphate are precipitated in the fluid. It was found that these particles are very active for forming hydroxyapatite from SBF and these particles were named Apatite Nuclei. By the discovery of Apatite Nuclei, it became possible to develop various multifunctional biomaterials possesing high bioaffinity in micron or nano scale by using biomimetic method. The authors have successfully encapsulated Ag, PLA and silicagel m...

  4. Insight into Biological Apatite: Physiochemical Properties and Preparation Approaches

    Directory of Open Access Journals (Sweden)

    Quan Liu

    2013-01-01

    Full Text Available Biological apatite is an inorganic calcium phosphate salt in apatite form and nano size with a biological derivation. It is also the main inorganic component of biological hard tissues such as bones and teeth of vertebrates. Consequently, biological apatite has a wide application in dentistry and orthopedics by using as dental fillers and bone substitutes for bone reconstruction and regeneration. Given this, it is of great significance to obtain a comprehensive understanding of its physiochemical and biological properties. However, upon the previous studies, inconsistent and inadequate data of such basic properties as the morphology, crystal size, chemical compositions, and solubility of biological apatite were reported. This may be ascribed to the differences in the source of raw materials that biological apatite are made from, as well as the effect of the preparation approaches. Hence, this paper is to provide some insights rather than a thorough review of the physiochemical properties as well as the advantages and drawbacks of various preparation methods of biological apatite.

  5. UV photofunctionalization promotes nano-biomimetic apatite deposition on titanium

    Directory of Open Access Journals (Sweden)

    Saita M

    2016-01-01

    Full Text Available Makiko Saita,1 Takayuki Ikeda,1,2 Masahiro Yamada,1,3 Katsuhiko Kimoto,4 Masaichi Chang-Il Lee,5 Takahiro Ogawa1 1Division of Advanced Prosthodontics, Weintraub Center for Reconstructive Biotechnology, UCLA School of Dentistry, Los Angeles, CA, USA; 2Department of Complete Denture Prosthodontics, Nihon University School of Dentistry, Yokosuka, Japan; 3Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan; 4Department of Prosthodontics and Oral Rehabilitation, 5Yokosuka-Shonan Disaster Health Emergency Research Center and ESR Laboratories, Kanagawa Dental University Graduate School of Dentistry, Yokosuka, Japan Background: Although biomimetic apatite coating is a promising way to provide titanium with osteoconductivity, the efficiency and quality of deposition is often poor. Most titanium implants have microscale surface morphology, and an addition of nanoscale features while preserving the micromorphology may provide further biological benefit. Here, we examined the effect of ultraviolet (UV light treatment of titanium, or photofunctionalization, on the efficacy of biomimetic apatite deposition on titanium and its biological capability.Methods and results: Micro-roughed titanium disks were prepared by acid-etching with sulfuric acid. Micro-roughened disks with or without photofunctionalization (20-minute exposure to UV light were immersed in simulated body fluid (SBF for 1 or 5 days. Photofunctionalized titanium disks were superhydrophilic and did not form surface air bubbles when immersed in SBF, whereas non-photofunctionalized disks were hydrophobic and largely covered with air bubbles during immersion. An apatite-related signal was observed by X-ray diffraction on photofunctionalized titanium after 1 day of SBF immersion, which was equivalent to the one observed after 5 days of immersion of control titanium. Scanning electron microscopy revealed nodular apatite deposition

  6. Tissue response of apatite-filled resin cement and titanium-reinforced apatite dental implants in dogs.

    Science.gov (United States)

    Ogiso, M; Tabata, T; Nakabayashi, N; Yamashita, Y; Borgese, D

    1993-01-01

    Abutment and root portion divided two-piece dental implants were designed to modify the one-piece dense hydroxyapatite (D-HAP) implant. The initial placement of the root portion endosseously ensured an aseptic environment and physical stability for the implant during the bone healing period. The outer D-HAP shell of the root portion was fortified by an inner titanium cylinder and cemented with an adhesive resin cement containing 4-methacryloyoxyethyl trimellitate anhydride (4-META) and reinforced by fine apatite filler. Upon attaining integration of the bone and implant, the abutment was screwed and fixed into the screw hole of the root portion. The tissue response of both the apatite-filled resin cement and root portion of the two-piece implant was studied by animal canine experiments. Light and electron microscopic examination of specimens taken from experimental animal tissue showed bone contacted directly not only the exposed apatite filler at the surface of the apatite-filled resin cement, but also the resin portion. These findings of direct bone contact suggested that the tissue response of apatite-filled resin cement was approximately similar to the usual D-HAP. Because most of the surface of the outer D-HAP shell of the root portion came in contact with bone, it prevented the deposition of contamination on the D-HAP surface during the manufacturing procedures of the root portion. PMID:10148567

  7. Lanthanum containing silicates and germanates as halogen apatites and oxyapatites

    International Nuclear Information System (INIS)

    Halogen apatites M4La6(XO4)6Z2 and oxyapatites M2La8(XO4)6O2 have been prepared: M = Sr, Pb, Ba; X = Si, Ge, and Z = F, Cl. The lattice parameters are discussed. The i.r. active internal vibrations of the silicate ion are assigned. A translational vibration of the 'free' oxide ions in the oxyapatites causes an intense absorption at about 400 cm-1 (silicates) and 350 cm-1 (germanates), respectively. The products 'M3La6(XO4)6' and 'M4La6(XO4)6O' are mixtures of various phases. Their respective apatite phase is a solid solution between M2La8(XO4)6O2 and the defect apatite M4La6(XO4)6Osub(vacant). Its composition mostly approximates to M2La8(XO4)6O2, however. (author)

  8. Isotropic radical CO{sub 2}{sup -} in biological apatites

    Energy Technology Data Exchange (ETDEWEB)

    Rudko, V.V. [Institute of Semiconductor Physics of National Academy of Sciences of Ukraine, 45, pr. Nauky, Kiev 03028 (Ukraine)], E-mail: vv_rudko@yahoo.com; Ishchenko, S.S.; Vorona, I.P.; Baran, N.P. [Institute of Semiconductor Physics of National Academy of Sciences of Ukraine, 45, pr. Nauky, Kiev 03028 (Ukraine)

    2007-10-15

    The isotropic CO{sub 2}{sup -} EPR spectrum at g{approx}2.0006 for {gamma}-irradiated powders of dental enamel annealed at different temperatures up to 320{sup 0}C is studied. The signal intensity is found to increase with the growth of annealing temperature up to 240{sup 0}C. This finding contradicts to the existing model of isotropic CO{sub 2}{sup -} radical in apatites. The possible models of the radical in biological apatite are analyzed and discussed. On the basis of the results obtained it is suggested that in tooth enamel apatite the isotropic CO{sub 2}{sup -} radical is the bulk radical localized in structural voids of hydroxyapatite lattice, which occur in the vicinity of a carbon radical in position B.

  9. Study of damage and helium diffusion in fluoro-apatites

    International Nuclear Information System (INIS)

    This work lies within the scope of the study of the radionuclides containment matrices. The choice of the fluoro-apatites as potential matrices of containment was suggested by the notable properties of these latter (thermal and chemical stability even under radioactive radiation). By irradiations with heavy ions and a helium implantation we simulated the effects related to the alpha radioactivity and to the spontaneous nuclear fission of the radionuclides. Thanks to the study of Durango fluoro-apatite single crystals and fluoro-apatite sintered ceramics, we evidenced that the damage fraction as well as the unit cell deformations increase with the electronic energy loss and with the substitution. These effects are followed at high fluences by a phenomenon of re-crystallization. The study of the helium diffusion points out that the thermal diffusion process improves with the substitution and strongly increases with heavy ions irradiation. (author)

  10. Electrochemical Studies of Paraquat Adsorbed onto Crystalline Apatite

    Directory of Open Access Journals (Sweden)

    Moulay Abderrahim EL MHAMMEDI

    2007-09-01

    Full Text Available The carbon paste electrode (CPE has been used to analyze the electrochemical behavior of paraquat (PQ adsorbed onto synthesized hydroxyapatite phosphocalcique (HAP in K2SO4 (0.1M. The cyclic voltammetry results obtained corrobate with square wave voltammetry. The influence of variables such as the concentration of paraquat adsorbed onto apatite (PQ/HAP, and the potential scan rate was tested.X-ray diffraction analysis (XRD, Fourier transformed infrared spectroscopy (FTIR analysis and inductively coupled plasma-atomic emission spectrometry (ICP, AES were used for characterization of the apatite.

  11. Depressing effect of sodium hexametaphosphate on apatite in flotation of rutile

    Institute of Scientific and Technical Information of China (English)

    Hao Ding; Hai Lin; Yanxi Deng

    2007-01-01

    The separation of mtile from apatite by flotation and the mechanism of depressing the apatite of sodium hexametaphosphate were studied. The results showed that rutile and apatite could be separated by using alkyl-imino-bismethylene phosphoric acid and sodium hexametaphosphate as a collector and a regulator, respectively. Sodium hexametaphosphate could selectively dissolve calcium ions on the apatite surface, and make calcium ions break away from lattice binding through combining.

  12. Separation of apatite ores and discrimination of oxidation zones using nuclear logging in the Khibiny apatite fields

    International Nuclear Information System (INIS)

    The problem of the correlation relationship between the P2O5 content and the apatite-nepheline ores density is solved. With a P2O5 content being the same as in apatite nepheline ores, the sphene-apatite ores are characterized by an excessive density Δrho(>=)0.11 g/c3. Oxidized ores can be defined by the value of the ratio eta=Na2O/K2O. Accuracy of Na2O determination by point measurements of NAK=N24 and K2O through a continuous spectrometric GK equals approximately 8%, whence it appears that the determination accuracy of eta is approximately 11-12%

  13. Carbon and oxygen isotopes in apatite CO2 and co-existing calcite

    International Nuclear Information System (INIS)

    Carbon and oxygen isotopes were analyzed in carbonate apatite CO2 and in co-existing calcite. Both C and O in apatite CO2 are enriched in the respective light isotopes relative to calcite. These results confirm the proposition that carbonate is part of the apatite structure

  14. Apatite-structured compounds: Synthesis and high-temperature investigation

    Energy Technology Data Exchange (ETDEWEB)

    Knyazev, Alexander V.; Chernorukov, Nikolai G. [Nizhny Novgorod State University, Gagarin Prospekt 23/2, 603950 Nizhny Novgorod (Russian Federation); Bulanov, Evgeny N., E-mail: bulanoven@yandex.ru [Nizhny Novgorod State University, Gagarin Prospekt 23/2, 603950 Nizhny Novgorod (Russian Federation)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer 25 Apatite-structured compounds of different composition were synthesized. Black-Right-Pointing-Pointer Phase transformations of them in wide temperature interval were investigated. Black-Right-Pointing-Pointer For the first time polymorphic transitions were observed on 6 apatites. Black-Right-Pointing-Pointer Thermal expansion coefficients of all studied phases were calculated. Black-Right-Pointing-Pointer The direct communication between thermal stability and expansion anisotropy was observed. - Abstract: The phase transitions and thermal expansion of apatite-structured compounds with the general formula M{sup II}{sub 5}(A{sup V}O{sub 4}){sub 3}L (M{sup II} = Ca, Sr, Cd, Ba, Pb; A{sup V} = P, V, Cr, Mn; L = OH, F, Cl, Br, I) have been studied by high-temperature X-ray diffraction and differential thermal analysis. Polymorphic transition nature was explained on the basis of the structure data. Connection between thermal stability and peculiarities of thermal expansion, which were explained in assumption of composition and structure of apatites was ascertained.

  15. Laser and spectroscopic properties of Yb-doped apatite crystals

    International Nuclear Information System (INIS)

    Favorable spectroscopic and laser properties were measured in several Yb-doped apatite crystals: Ca5(PO4)3F, Sr5(PO4)3F, and Ca5-xSrx(PO4)3F (x=1-3). The properties included absorption and emission spectra, and laser pumping (slope efficiency)

  16. Apatite: a new redox proxy for silicic magmas?

    Science.gov (United States)

    Miles, Andrew; Graham, Colin; Hawkesworth, Chris; Gillespie, Martin; Bromiley, Geoff; Hinton, Richard

    2015-04-01

    The oxidation states of magmas provide valuable information about the release and speciation of volatile elements during volcanic eruptions, metallogenesis, source rock compositions, open system magmatic processes, tectonic settings and potentially titanium (Ti) activity in chemical systems used for Ti-dependent geothermometers and geobarometers. In this presentation we explore the use of Mn in apatite as an oxybarometer in intermediate and silicic igneous rocks. Increased Mn concentrations in apatite in granitic rocks from the zoned Criffell granitic pluton (southern Scotland) correlate with decreasing Fe2O3 (Fe3+) and Mn in the whole-rock and likely reflect increased Mn2+/Mn3+and greater compatibility of Mn2+ relative to Mn3+ in apatite under reduced conditions. Fe3+/Fe2+ ratios in biotites have previously been used to calculate oxygen fugacities (fO2) in the outer zone granodiorites and inner zone granites where redox conditions have been shown to change from close to the magnetite-hematite buffer to close to the nickel-nickel oxide buffer respectively[1]. This trend is apparent in apatite Mn concentrations from a range of intermediate to silicic volcanic rocks that exhibit varying redox states and are shown to vary linearly and negatively with log fO2, such that logfO2=-0.0022(±0.0003)Mn(ppm)-9.75(±0.46) Variations in the Mn concentration of apatites appear to be largely independent of differences in the Mn concentration of the melt. Apatite Mn concentrations may therefore provide an independent oxybarometer that is amenable to experimental calibration, with major relevance to studies on detrital mineral suites, particularly those containing a record of early Earth redox conditions, and on the climatic impact of historic volcanic eruptions[2]. [1] Stephens, W. E., Whitley, J. E., Thirlwall, M. F. and Halliday, A. N. (1985) The Criffell zoned pluton: correlated behaviour of rare earth element abundances with isotopic systems. Contributions to Mineralogy and

  17. Development of Biomimetic Needle-like Apatite Nanocrystals by a Simple New Method

    Institute of Scientific and Technical Information of China (English)

    Jie WEI; Yubao LI; Yi ZUO; Xueling PENG; Li ZHANG

    2004-01-01

    A new method of calcium nitrate and sodium phosphate as reactants was employed to prepare biomimetic apatite nanocrystals by a simple heating treatment in water. The structure and properties of the apatite crystals were investigated by TEM, XRD, IR, ICP and TG. It is found that the apatite nanocrystals contain OH-, CO32-, Na+ and HPO~- ions in their crystal structure. The crystal water is removed during heating from 200℃ to 400℃. CO32-and HPO~- are decomposed at 600℃ to 800℃, also there is lattice water lost at this temperature stage. The morphology of the apatite nanocrystals is needle-like with a length less than 80 nm. The size and crystallinity of the apatite nanocrystals increase with water treatment temperature and time. Compared to the apatite crystals sintered at 800℃, water treated apatite nanocrystals are poorly crystallized apatite. The results indicate that the apatite nanocrystals have similarity in composition, structure, morphology and crystallinity to that of bone apatite crystals. It can be used to make apatite crystals/polymer biomimetic bone repair materials or for other biomedical applications.

  18. Biomimetic synthesis and biocompatibility evaluation of carbonated apatites template-mediated by heparin

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Yi [Department of Oral and Maxillofacial Surgery, Laboratory of Interdisciplinary Studies, School and Hospital of Stomatology, Peking University, Beijing 100081 (China); Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Sun, Yuhua [Department of Oral and Maxillofacial Surgery, Laboratory of Interdisciplinary Studies, School and Hospital of Stomatology, Peking University, Beijing 100081 (China); Chen, Xiaofang [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Zhu, Peizhi, E-mail: pzzhu@umich.edu [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055 (United States); Wei, Shicheng, E-mail: sc-wei@pku.edu.cn [Department of Oral and Maxillofacial Surgery, Laboratory of Interdisciplinary Studies, School and Hospital of Stomatology, Peking University, Beijing 100081 (China); Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China)

    2013-07-01

    Biomimetic synthesis of carbonated apatites with good biocompatibility is a promising strategy for the broadening application of apatites for bone tissue engineering. Most researchers were interested in collagen or gelatin-based templates for synthesis of apatite minerals. Inspired by recent findings about the important role of polysaccharides in bone biomineralization, here we reported that heparin, a mucopolysaccharide, was used to synthesize carbonated apatites in vitro. The results indicated that the Ca/P ratio, carbon content, crystallinity and morphology of the apatites varied depending on the heparin concentration and the initial pH value. The morphology of apatite changed from flake-shaped to needle-shaped, and the degree of crystallinity decreased with the increasing of heparin concentration. Biocompatibility of the apatites was tested by proliferation and alkaline phosphatase activity of MC3T3-E1 cells. The results suggested that carbonated apatites synthesized in the presence of heparin were more favorable to the proliferation and differentiation of MC3T3-E1 cells compared with traditional method. In summary, the heparin concentration and the initial pH value play a key role in the chemical constitution and morphology, as well as biological properties of apatites. These biocompatible nano-apatite crystals hold great potential to be applied as bioactive materials for bone tissue engineering. - Highlights: • Heparin was used as a template to synthesize needle-shaped nano-apatite. • Changing the pH value and concentration led to different properties of apatite. • Apatite prepared by heparin was more favorable to the osteogenic differentiation. • Possible synthesis mechanism of apatite templated by heparin was described.

  19. Biomimetic synthesis and biocompatibility evaluation of carbonated apatites template-mediated by heparin

    International Nuclear Information System (INIS)

    Biomimetic synthesis of carbonated apatites with good biocompatibility is a promising strategy for the broadening application of apatites for bone tissue engineering. Most researchers were interested in collagen or gelatin-based templates for synthesis of apatite minerals. Inspired by recent findings about the important role of polysaccharides in bone biomineralization, here we reported that heparin, a mucopolysaccharide, was used to synthesize carbonated apatites in vitro. The results indicated that the Ca/P ratio, carbon content, crystallinity and morphology of the apatites varied depending on the heparin concentration and the initial pH value. The morphology of apatite changed from flake-shaped to needle-shaped, and the degree of crystallinity decreased with the increasing of heparin concentration. Biocompatibility of the apatites was tested by proliferation and alkaline phosphatase activity of MC3T3-E1 cells. The results suggested that carbonated apatites synthesized in the presence of heparin were more favorable to the proliferation and differentiation of MC3T3-E1 cells compared with traditional method. In summary, the heparin concentration and the initial pH value play a key role in the chemical constitution and morphology, as well as biological properties of apatites. These biocompatible nano-apatite crystals hold great potential to be applied as bioactive materials for bone tissue engineering. - Highlights: • Heparin was used as a template to synthesize needle-shaped nano-apatite. • Changing the pH value and concentration led to different properties of apatite. • Apatite prepared by heparin was more favorable to the osteogenic differentiation. • Possible synthesis mechanism of apatite templated by heparin was described

  20. Laser-SNMS analysis of apatite formation in vitro

    Science.gov (United States)

    Dambach, S.; Fartmann, M.; Kriegeskotte, C.; Brüning, C.; Wiesmann, H. P.; Lipinsky, D.; Arlinghaus, H. F.

    2004-06-01

    We have applied nonresonant laser secondary neutral mass spectrometry (Laser-SNMS) to examine different states of biomineralization in vitro. Primary osteoblast-like cells derived from bovine metacarpals were cultured for 5 weeks on clean smooth silicon substrates. For mass spectrometric investigations, the cells and newly formed mineral were cryofixed, freeze-fractured, and freeze-dried. The results indicate that in the vicinity of single osteoblasts, extracellular enrichment of potassium typically occurs during the initial stages of mineralization. Potassium may interact with matrix macromolecules and prevent an uncontrolled apatite deposition. However, apatite biomineral formation is correlated with a potassium release. In conclusion, potassium seems to be involved in the process of extracellular matrix biomineralization.

  1. Thermal annealing of fission tracks in synthetic apatites

    OpenAIRE

    Carpena, J.; Lacout, Jean-Louis

    2010-01-01

    Synthetic analogues of poor-silicated natural apatites have been doped with uranium. These minerals have been irradiated with a thermal neutron dose in the aim to induce the 235U fission and to obtain a fission track population. Thermal annealing experiments have been performed on the fission track population and allow us to compare the ability of the synthetic minerals to anneal such nuclear damages with their natural analogues. The thermal of the fission tracks in the synthetic minerals nee...

  2. Formation of Ultrafine Apatite Fibers by Sol-gel/Electrospinning

    Institute of Scientific and Technical Information of China (English)

    DING Ya-mei; YUAN Xiao-yan; ZHAO Jin; GUO Wan-chun; WANG Xiu-kui

    2007-01-01

    Ultrafine apatite fibers were prepared by electrospinning of sol-gel precursor/poly(vinyl pyrrolidone)(PVP) solutions followed by subsequent calcination. The as-electrospun and calcinated fibers were observed under a scanning electron microscope and an optical polarizing microscope. Results show that the morphology and the diameter of as-electrospun fibers strongly depend on the viscosity and the surface tension of sol-gel precursor/PVP solutions. After calcination, the smooth as-electrospun fibers shrink and the fiber diameter decreases because of the removal of the polymer. The chemical evolution upon the transformation of the precursor from a gel to the final apatite fibers was investigated by thermogravimetric-differential thermal analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. It is thus suggested that the crystalline structure of the calcined fibers is largely influenced by the calcination temperature. After being calcined at 600 ℃, the apatite fibers with a diameter of about 280 nm containing β-tricalcium phosphate were obtained.

  3. Structural studies of synthetic calcium and lead apatites

    International Nuclear Information System (INIS)

    Full text: Hydroxyapatite, Ca10(PO4)6(OH)2, is a major mineral component of calcified tissues, including bones and teeth. It is a good model system for natural apatites, having a structure which can easily accommodate a great variety of anionic and cationic substitutions. It acts as a natural sink for heavy metals, especially Pb and Cd, in biological systems. The hydroxyl ion can be replaced by other anions and one aim of the present work is to establish how such substitutions influence the ability of apatites to sequest and immobilise heavy metals. Environmentally speaking, there is still a lot of industrial use for Pb and the halide substituted apatite as lead chlorapatite, Pb10(PO4)6Cl2, which is found in Pb contaminated soils. This leads to interest in looking at the ability to release Pb encapsulated in mineral bodies and to develop methods that can selectively remove Pb from contaminated sites. We have used a combination of synchrotron X-ray diffraction and high resolution powder neutron diffraction methods for our structural studies of some substituted apatites. We have refined the structures of eight apatites M10(PO4)6X2, where M = Pb, Ca and X = OH, F, Cl, Br, using the Rietveld method. In these there are two cation sites, a channel of M-I atoms and a triangle of M-II atoms. The anion interacts most strongly with the M-II atoms at (↓, deg , 1/4). For the Ca compounds, the F ion sits within the triangles at (0, 0, 1/4), while the larger OH and Cl anions are disordered above and below the M-II triangles. The Br is at (0, 0, 1/2). Despite the larger size of the isostructural Pb compounds, no anions are found in the triangles. The F, Cl and Br ions are at (0, 0, 1/2) and the OH ion is disordered at (0, 0, z). This difference in behaviour is possibly related to the stereochemical activity of the Pb 6s electrons. While synchrotron X-ray methods have been important in determining the positional parameters of the heavy elements (eg. Pb, Ca), neutron scattering

  4. Partition coefficients of Hf, Zr, and REE between zircon, apatite, and liquid

    Science.gov (United States)

    Fujimaki, H.

    1986-01-01

    Concentration ratios of Hf, Zr, and REE between zircon, apatite, and liquid were determined for three igneous compositions: two andesites and a diorite. The concentration ratios of these elements between zircon and corresponding liquid can approximate the partition coefficient. Although the concentration ratios between apatite and andesite groundmass can be considered as partition coefficients, those for the apatite in the diorite may deviate from the partition coefficients. The HREE partition coefficients between zircon and liquid are very large (100 for Er to 500 for Lu), and the Hf partition coefficient is even larger. The REE partition coefficients between apatite and liquid are convex upward, and large (D=10-100), whereas the Hf and Zr partition coefficients are less than 1. The large differences between partition coefficients of Lu and Hf for zircon-liquid and for apatite-liquid are confirmed. These partition coefficients are useful for petrogenetic models involving zircon and apatite. ?? 1986 Springer-Verlag.

  5. Phosphorus removal by apatite in horizontal flow constructed wetlands: kinetics and treatment reliability

    OpenAIRE

    Harouiya, N.; Molle, P.; Prost Boucle, S.; Liénard, A.

    2008-01-01

    Phosphorus removal in constructed wetlands have received particular attention last decades by using specific materials promoting adsorption/precipitation mechanisms. Recent studies have shown interest in using apatite materials to promote P precipitation onto the particle surface. As previous trials were mainly done by lab experiments, this present study aims to evaluate the real potential of apatites to remove P from wastewater in pilots and a full-scale plant. Two different apatites have be...

  6. Resorption of apatite-wollastonite containing glass-ceramic and beta-tricalcium phosphate in vivo.

    Science.gov (United States)

    Teramoto, Hidefumi; Kawai, Akira; Sugihara, Shinsuke; Yoshida, Aki; Inoue, Hajime

    2005-10-01

    Apatite-wollastonite containing glass ceramic is considered to be difficult to resorb, but we experienced the disappearance of the porous type of Apatite-wollastonite glass ceramic particles . In this study, the resorption of porous apatite-wollastonite glass-ceramic implanted in the femurs of rabbits was investigated, and the process was compared with beta-tricalcium phosphate, a resorbable ceramics. Porous apatite-wollastonite glass-ceramic (70, 80, and 90% porosity) and beta-tricalcium phosphate (75% porosity) were implanted in the femurs of Japanese white rabbits. Samples were harvested and examined 0, 4, 8, 12, 24 and 36 weeks after implantation. Quantitative analysis of the radiographic and histologic findings was performed with NIH Image software. Radiographic examination demonstrated that the radiopacity and size of the porous apatite-wollastonite glassceramic cylinders decreased gradually after implantation. Histologic examination revealed that the surface area of the apatite-wollastonite glass-ceramic cylinders decreased continuously, and approached 20% of the original area 36 weeks after implantation. However, the resorption rate of porous apatite-wollastonite glass-ceramic was slower than that of beta-tricalcium phosphate. Toluidine blue staining showed abundant new bone formation on the surface of the apatite-wollastonite glassceramic matrix. Considering its mechanical strength, gradual resorption characteristics, and good osteochonductive activity, porous apatite-wollastonite glass-ceramic appears to be a suitable artificial bone substitutes. PMID:16286959

  7. Resorption of apatite-wollastonite containing glass-ceramic and beta-tricalcium phosphate in vivo.

    Directory of Open Access Journals (Sweden)

    Teramoto,Hidefumi

    2005-10-01

    Full Text Available

    Apatite-wollastonite containing glass ceramic is considered to be difficult to resorb, but we experienced the disappearance of the porous type of Apatite-wollastonite glass ceramic particles . In this study, the resorption of porous apatite-wollastonite glass-ceramic implanted in the femurs of rabbits was investigated, and the process was compared with beta-tricalcium phosphate, a resorbable ceramics. Porous apatite-wollastonite glass-ceramic (70, 80, and 90% porosity and beta-tricalcium phosphate (75% porosity were implanted in the femurs of Japanese white rabbits. Samples were harvested and examined 0, 4, 8, 12, 24 and 36 weeks after implantation. Quantitative analysis of the radiographic and histologic findings was performed with NIH Image software. Radiographic examination demonstrated that the radiopacity and size of the porous apatite-wollastonite glassceramic cylinders decreased gradually after implantation. Histologic examination revealed that the surface area of the apatite-wollastonite glass-ceramic cylinders decreased continuously, and approached 20% of the original area 36 weeks after implantation. However, the resorption rate of porous apatite-wollastonite glass-ceramic was slower than that of beta-tricalcium phosphate. Toluidine blue staining showed abundant new bone formation on the surface of the apatite-wollastonite glassceramic matrix. Considering its mechanical strength, gradual resorption characteristics, and good osteochonductive activity, porous apatite-wollastonite glass-ceramic appears to be a suitable artificial bone substitutes.

  8. Molecular functionalization of tantalum oxide surface towards development of apatite growth

    International Nuclear Information System (INIS)

    We have studied the apatite growth dynamics on tantalum oxide surfaces. This nucleation is obtained via an organosilane intermediate layer between the apatite and the substrate surface. Four organosilane layers (differing by their terminal functionality) were investigated. Their characterization with atomic force microscopy and other techniques such as X-ray photoelectron spectroscopy (XPS) and wetting measurements highlighted the influence of the organosilane terminal groups on the apatite growth rates. Results revealed that apatite is indeed growing faster on phosphate terminal groups than on the three other groups studied (vinyl, hydroxyl and carboxyl).

  9. Apatite as probe for the halogen composition of metamorphic fluids (Bamble Sector, SE Norway)

    Science.gov (United States)

    Kusebauch, Christof; John, Timm; Whitehouse, Martin J.; Engvik, Ane K.

    2015-10-01

    Halogen composition of replaced apatite formed during a regional metasomatic event (Bamble Sector, SE Norway) reveals information about the composition and evolution of the hydrothermal fluid. Infiltration and pervasive fluid flow of highly saline fluids into gabbroic bodies lead to scapolitization and amphibolitization, where magmatic Cl-rich apatite reacts with the hydrothermal fluid to form OH- and/or F-rich apatite. Apatite from highly altered samples adjacent to the shear zone has highest F (up to 15,000 µg/g) and lowest Br (4-25 µg/g) concentrations, whereas apatite from least altered samples has very low F (30-200 µg/g) and high Br (30-85 µg/g). In addition, individual replaced apatite grains show a zonation in F with high concentrations along rims and cracks and low F in core regions. Iodine concentrations remain rather constant as low values of 0.18-0.70 µg/g. We interpret all observed compositional features of replaced apatite to be the result of a continuous evolution of the fluid during fluid-rock interaction. Due to its high compatibility, F from the infiltrating fluid is incorporated early into recrystallized apatite (close to shear zone and rims of individual apatite grains). In contrast, Br as an incompatible halogen becomes enriched in the fluid and is highest in the most evolved fluid. Using experimental partition data between replaced apatite and fluid, we calculated F concentrations of the evolving fluid to decrease from 60 to correlated with OH-rich zones of replaced apatite, whereas low δ 37Cl values are measured in F-rich zones of replaced apatite and in Cl-apatite of probably magmatic origin. Though apatite δ 37Cl values follow the general bulk trend, the individual δ 37Cl signature seems to reflect the highly localized composition of interfacial fluid at the reaction front. Our observations suggest that apatite can be used as a fluid probe for F, Br, and I to detect a compositional evolution of the fluid, which can be quantified by

  10. Characterization of antiseptic apatite powders prepared at biomimetics temperature and pH

    Directory of Open Access Journals (Sweden)

    Soumia Belouafa

    2008-03-01

    Full Text Available Antiseptic apatite-based calcium phosphates were prepared as the single-phase powders. Phosphocalcic oxygenated apatites were synthesized from calcium salts and orthophosphate dissolved in oxygenated water solution at 30%, under the biomimetic conditions of 37 °C and pH 7.4. The characterization and chemical analysis of the synthesized biomimetic apatite powders were performed by scanning electron microscopy (SEM, powder X ray diffraction (XRD, Fourier-transformed infrared spectroscopy (FT-IR and chemical analysis. The obtained materials are a calcium deficient apatites with different morphologies.

  11. Evaluation of apatite silicates as solid oxide fuel cell electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Marrero-Lopez, D. [Dpto. de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain); Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Martin-Sedeno, M.C.; Aranda, M.A.G. [Dpto. de Quimica Inorganica, Universidad Malaga, 29071 Malaga (Spain); Pena-Martinez, J. [Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Instituto de Energias Renovables, Parque Tecnologico, Universidad de Castilla La Mancha, 02006 Albacete (Spain); Ruiz-Morales, J.C.; Nunez, P. [Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Ramos-Barrado, J.R. [Dpto. de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain)

    2010-05-01

    Apatite-type silicates have been considered as promising electrolytes for Solid Oxide Fuel Cells (SOFC); however studies on the potential use of these materials in SOFC devices have received relatively little attention. The lanthanum silicate with composition La{sub 10}Si{sub 5.5}Al{sub 0.5}O{sub 26.75} has been evaluated as electrolyte with the electrode materials commonly used in SOFC, i.e. manganite, ferrite and cobaltite as cathode materials and NiO-CGO composite, chromium-manganite and Sr{sub 2}MgMoO{sub 6} as anode materials. Chemical compatibility, area-specific resistance and fuel cell studies have been performed. X-ray powder diffraction (XRPD) analysis did not reveal any trace of reaction products between the apatite electrolyte and most of the aforementioned electrode materials. However, the area-specific polarisation resistance (ASR) of these electrodes in contact with apatite electrolyte increased significantly with the sintering temperature, indicating reactivity at the electrolyte/electrode interface. On the other hand, the ASR values are significantly improved using a ceria buffer layer between the electrolyte and electrode materials to prevent reactivity. Maximum power densities of 195 and 65 mWcm{sup -2} were obtained at 850 and 700 C, respectively in H{sub 2} fuel, using an 1 mm-thick electrolyte, a NiO-Ce{sub 0.8}Gd{sub 0.2}O{sub 1.9} composite as anode and La{sub 0.6}Sr{sub 0.4}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} as cathode materials. This fuel cell was tested for 100 h in 5%H{sub 2}-Ar atmosphere showing stable performance. (author)

  12. Thermal expansion of solid solutions in apatite binary systems

    Energy Technology Data Exchange (ETDEWEB)

    Knyazev, Alexander V.; Bulanov, Evgeny N., E-mail: bulanoven@gmail.com; Korokin, Vitaly Zh.

    2015-01-15

    Graphical abstract: Thermal dependencies of volume thermal expansion parameter for with thermal expansion diagrams for Pb{sub 5}(PO{sub 4}){sub 3}F{sub x}Cl{sub 1−x}. - Highlights: • Solid solutions in three apatitic binary systems were investigated via HT-XRD. • Thermal expansion coefficients of solid solutions in the systems were calculated. • Features of the thermal deformation of the apatites were described. • Termoroentgenography is a sensitive method for the investigation of isomorphism. - Abstract: High-temperature insitu X-ray diffraction was used to investigate isomorphism and the thermal expansion of apatite-structured compounds in three binary systems in the entire temperature range of the existence of its hexagonal modifications. Most of the studied compounds are highly expandable (α{sub l} > 8 × 10{sup 6} (K{sup −1})). In Pb{sub 5}(PO{sub 4}){sub 3}F–Pb{sub 5}(PO{sub 4}){sub 3}Cl system, volume thermal expansion coefficient is independence from the composition at 573 K. In Pb{sub 5}(PO{sub 4}){sub 3}Cl–Pb{sub 5}(VO{sub 4}){sub 3}Cl, the compound with equimolar ratio of substituted atoms has constant volume thermal expansion coefficient in temperature range 298–973 K. Ca{sub 5}(PO{sub 4}){sub 3}Cl–Pb{sub 5}(PO{sub 4}){sub 3}Cl system is characterized by the most thermal sensitive composition, in which there is an equal ratio of isomorphic substituted atoms.

  13. Cosmogenic and nucleogenic ^3He in apatite, titanite, and zircon

    OpenAIRE

    Farley, K. A.; Libarkin, J.; Mukhopadhyay, S; Amidon, W.

    2006-01-01

    Cosmogenic ^3He was measured in apatite, titanite, and zircon and cosmogenic ^(21)Ne in quartz at 13 depth intervals in a 2.7-m long drill core in a Miocene ignimbrite from the Altiplano of Bolivia. All three ^3He depth profiles as well as the ^(21)Ne profile attenuate exponentially with depth, indicating that both of these isotopes are cosmogenic in origin with no significant contribution from other sources. The attenuation lengthscale for ^3He production of Λ = 180 ± 11 g/cm^2 is consistent...

  14. In vitro apatite formation on polyamide containing carboxyl groups modified with silanol groups.

    Science.gov (United States)

    Kawai, Takahiro; Ohtsuki, Chikara; Kamitakahara, Masanobu; Hosoya, Kayo; Tanihara, Masao; Miyazaki, Toshiki; Sakaguchi, Yoshimitsu; Konagaya, Shigeji

    2007-06-01

    Modification of organic polymer with silanol groups in combination with calcium salts enables the polymer to show bioactivity, that is, the polymer forms apatite on its surface after exposure to body environment. However, how modification with silanol groups influences ability of apatite formation on the polymer substrate and adhesive strength between polymer and apatite is not yet known. In the present study, polyamide containing carboxyl groups was modified with different amounts of silanol groups, and its apatite-forming ability in 1.5SBF, which contained ion concentrations 1.5 times those of simulated body fluid (SBF), was examined. The rate of apatite formation increased with increasing content of silanol groups in the polyamide films. This may be attributed to enhancement of dipole interactions. A tendency for the adhesive strength of the apatite layer on the polyamide film to be decreased with increasing content of silanol groups was observed. This may be attributed to swelling in 1.5SBF and having a high degree of shrinkage after drying. These findings clearly show that modification of organic polymers with the functional groups induces apatite deposition, and also determines the adhesive strength of the apatite layer to the organic substrates. PMID:17243002

  15. Study of Thermal Activated CO2 Extraction Processes from Carbonate Apatites Using Gas Chromatography

    Directory of Open Access Journals (Sweden)

    V.N. Kuznetsov

    2015-10-01

    Full Text Available The study of carbonate in the structure of carbonate-containing apatites (CCA is an actual problem due to the similarity of such systems to natural apatites of mammalian bone tissue. The search of the optimal synthesis procedures was also carried out in order to obtain carbonate apatites with the highest rate of carbonate ions incorporation into the apatite structure. The analysis of carbonate-group temperature behavior in apatites of various origin helps to understand their structural and functional roles in biologically relevant apatite materials. The thermal extraction and accumulation of CO2 from biogenic and geological apatites is also of interest for the further carbon isotope analysis with accelerating mass-spectrometry. X-ray diffraction analysis, infrared spectroscopy and scanning electron microscopy as well as self-proposed gas chromatography method with thermo-programmed probe extraction were used for carbonate temperature behavior study. This new method allows determining CO2 concentration released from CCA during annealing. The defined changes in carbonate apatite structure depending on synthesis procedure were observed.

  16. Mineralogical studies of apatites of Gara-aghaj deposit from mineral processing viewpoint

    International Nuclear Information System (INIS)

    Gara-aghaj deposit located 36 km northwest of urumieh is one of the titanium phosphorous resources in Iran. The previous exploration studies indicated that there is 102 Mt phosphorous ore deposit with average grading of 2.3percentP2O5. In this research, the mineralogical studies of collected representative samples were performed by XRD, XRF, optical microscopy and SEM equipped by EDX. These studies indicated that ilmenite, magnetite and apatite are the main valuable minerals. The gangue minerals consist of the silicate minerals such as pyroxene, olivine, plagioclase and some secondary minerals. Analysis of apatite by EDX showed the presence of fluor-apatite in the ore. From textural viewpoint, apatites is mainly interlocked with ilmenite, magnetite and some gangue minerals with 60 microns liberation degree but there are some inclusions of apatite inside ilmenite and magnetite. The heavy liquid separation tests indicated that the first type of apatites, with density of 3, is mainly concentrated in tailing of gravity separation methods. This type of apatites is recoverable by flotation method. So, apatite concentrate can be obtained as a by-product of ilmenite concentration process by gravity methods.

  17. U-Th-He dating of apatite: A potential thermochronometer

    International Nuclear Information System (INIS)

    The authors found a gem quality crystal of Durango fluorapatite to have a 4He content consistent with complete retention of radiogenic helium since its formation at about 31 Ma. Isothermal heating and step-heating analysis reveal 4He loss to occur systematically by volume diffusion at low temperatures. The linear, low-temperature portion of the diffusion data yields an activation energy of 38.5 ± 8.1 kcal/mol and a frequency factor of 1n (D0/a2) = 16.4 ± 2.8 sec-1, corresponding to a closure temperature of 105 degree C ± 30 degree C (cooling rate 10 degree C/m.y.). It appears that U-Th-He dating of apatite might represent a useful new thermochronometer with a range similar to that of fission-track dating of apatite. From these results, they infer that a number of the too-young U-Th-He dates reported in the literature on minerals such as zircon and magnetite may in fact represent valuable records of the low-temperature thermal history of their host rocks

  18. On the development of an apatitic calcium phosphate bone cement

    Indian Academy of Sciences (India)

    Manoj Komath; H K Varma; R Sivakumar

    2000-04-01

    Development of an apatitic calcium phosphate bone cement is reported. 100 Particles of tetracalcium phosphate (TTCP) and dicalcium phosphate dihydrate (DCPD) were mixed in equimolar ratio to form the cement powder. The wetting medium used was distilled water with Na2HPO4 as accelerator to manipulate the setting time. The cement powder, on wetting with the medium, formed a workable putty. The setting times of the putty were measured using a Vicat type apparatus and the compressive strength was determined with a Universal Testing Machine. The nature of the precipitated cement was analyzed through X-ray diffraction (XRD), fourier transform infrared spectrometry (FTIR) and energy dispersive electron microprobe (EDAX). The results showed the phase to be apatitic with a calcium–to–phosphorous ratio close to that of hydroxyapatite. The microstructure analysis using scanning electron microscopy (SEM) showed hydroxyapatite nanocrystallite growth over particulate matrix surface. The structure has an apparent porosity of ∼ 52%. There were no appreciable dimensional or thermal changes during setting. The cement passed the in vitro toxicological screening (cytotoxicity and haemolysis) tests. Optimization of the cement was done by manipulating the accelerator concentration so that the setting time, hardening time and the compressive strength had clinically relevant values.

  19. Endogenous Lunar Volatiles: Insights into the Abundances of Volatiles in the Moon from Lunar Apatite

    Science.gov (United States)

    McCubbin, Francis

    2016-01-01

    At the time of publication of New Views of the Moon, it was thought that the Moon was bone dry with less than about 1 ppb H2O. However in 2007, initial reports at the 38th Lunar and Planetary Science Conference speculated that H-species were present in both apatites and pyroclastic volcanic lunar glasses. These early reports were later confirmed through peer-review, which motivated many subsequent studies on magmatic volatiles in and on the Moon within the last decade. Some of these studies have cast into question the post-Apollo view of lunar formation, the distribution and sources of volatiles in the Earth-Moon system, and the thermal and magmatic evolution of the Moon. The mineral apatite has been one of the pillars of this new field of study, and it will be the primary focus of this abstract. Although apatite has been used both to understand the abundances of volatiles in lunar systems as well as the isotopic compositions of those volatiles, the focus here will be on the abundances of F, Cl, and H2O. This work demonstrates the utility of apatite in advancing our understanding of lunar volatiles, hence apatite should be among the topics covered in the endogenous lunar volatile chapter in NVM II. Truncated ternary plot of apatite X-site occupancy (mol%) from highlands apatite and mare basalt apatite plotted on the relative volatile abundance diagram from. The solid black lines delineate fields of relative abundances of F, Cl, and H2O (on a weight basis) in the melt from which the apatite crystallized. The diagram was constructed using available apatite/melt partitioning data for fluorine, chlorine, and hydroxyl.

  20. Apatite precipitation on a novel fast-setting calcium silicate cement containing fluoride

    Science.gov (United States)

    Ranjkesh, Bahram; Chevallier, Jacques; Salehi, Hamideh; Cuisinier, Frédéric; Isidor, Flemming; Løvschall, Henrik

    2016-01-01

    Abstract Aim: Calcium silicate cements are widely used in endodontics. Novel fast-setting calcium silicate cement with fluoride (Protooth) has been developed for potential applications in teeth crowns including cavity lining and cementation. Objective: To evaluate the surface apatite-forming ability of Protooth compositions as a function of fluoride content and immersion time in phosphate-buffered saline (PBS). Material and methods: Three cement compositions were tested: Protooth (3.5% fluoride and 10% radiocontrast), ultrafast Protooth (3.5% fluoride and 20% radiocontrast), and high fluoride Protooth (15% fluoride and 25% radiocontrast). Powders were cap-mixed with liquid, filled to the molds and immersed in PBS. Scanning electron microscopy, energy dispersive X-ray analysis, and Raman spectroscopy were used to characterize the precipitations morphology and composition after 1, 7, 28, and 56 days. Apatite/belite Raman peak height indicated the apatite thickness. Results: Spherical calcium phosphate precipitations with acicular crystallites were formed after 1-day immersion in PBS and Raman spectra disclosed the phosphate band at 965 cm−1, supporting the apatite formation over Protooth compositions. The apatite deposition continued and more voluminous precipitations were observed after 56 days over the surface of all cements. Raman bands suggested the formation of β-type carbonated apatite over Protooth compositions. High fluoride Protooth showed the most compact deposition with significantly higher apatite/belite ratio compared to Protooth and ultrafast Protooth after 28 and 56 days. Conclusions: Calcium phosphate precipitations (apatite) were formed over Protooth compositions after immersion in PBS with increasing apatite formation as a function of time. High fluoride Protooth exhibited thicker apatite deposition. PMID:27335901

  1. Incorporation of iodine into apatite structure: a crystal chemistry approach using Artificial Neural Network

    Science.gov (United States)

    Wang, Jianwei

    2015-06-01

    Materials with apatite crystal structure provide a great potential for incorporating the long-lived radioactive iodine isotope (129I) in the form of iodide (I-) from nuclear waste streams. Because of its durability and potentially high iodine content, the apatite waste form can reduce iodine release rate and minimize the waste volume. Crystal structure and composition of apatite was investigated for iodide incorporation into the channel of the structure using Artificial Neural Network. A total of 86 experimentally determined apatite crystal structures of different compositions were compiled from literature, and 46 of them were used to train the networks and 42 were used to test the performance of the trained networks. The results show that the performances of the networks are satisfactory for predictions of unit cell parameters a and c and channel size of the structure. The trained and tested networks were then used to predict unknown compositions of apatite that incorporates iodide. With a crystal chemistry consideration, chemical compositions that lead to matching the size of the structural channel to the size of iodide were then predicted to be able to incorporate iodide in the structural channel. The calculations suggest that combinations of A site cations of Ag+, K+, Sr2+, Pb2+, Ba2+, and Cs+, and X site cations, mostly formed tetrahedron, of Mn5+, As5+, Cr5+, V5+, Mo5+, Si4+, Ge4+, and Re7+ are possible apatite compositions that are able to incorporate iodide. The charge balance of different apatite compositions can be achieved by multiple substitutions at a single site or coupled substitutions at both A and X sites. The results give important clues for designing experiments to synthesize new apatite compositions and also provide a fundamental understanding how iodide is incorporated in the apatite structure. This understanding can provide important insights for apatite waste forms design by optimizing the chemical composition and synthesis procedure.

  2. Biomimetic magnesium–carbonate-apatite nanocrystals endowed with strontium ions as anti-osteoporotic trigger

    Energy Technology Data Exchange (ETDEWEB)

    Iafisco, Michele, E-mail: michele.iafisco@istec.cnr.it; Ruffini, Andrea; Adamiano, Alessio; Sprio, Simone; Tampieri, Anna

    2014-02-01

    The present work investigates the preparation of biomimetic nanocrystalline apatites co-substituted with Mg, CO{sub 3} and Sr to be used as starting materials for the development of nanostructured bio-devices for regeneration of osteoporotic bone. Biological-like amounts of Mg and CO{sub 3} ions were inserted in the apatite structure to mimic the composition of bone apatite, whereas the addition of increasing quantities of Sr ions, from 0 up to 12 wt.%, as anti-osteoporotic agent, was evaluated. The chemical–physical features, the morphology, the degradation rates, the ion release kinetics as well as the in vitro bioactivity of the as-prepared apatites were fully evaluated. The results indicated that the incorporation of 12 wt.% of Sr can be viewed as a threshold for the structural stability of Mg–CO{sub 3}-apatite. Indeed, incorporation of lower quantity of Sr did not induce considerable variations in the chemical structure of Mg–CO{sub 3}-apatite, while when the Sr doping extent reached 12 wt.%, a dramatically destabilizing effect was detected on the crystal structure thus yielding alteration of the symmetry and distortion of the PO{sub 4}. As a consequence, this apatite exhibited the fastest degradation kinetic and the highest amount of Sr ions released when tested in physiological conditions. In this respect, the surface crystallization of new calcium phosphate phase when immersed in physiological-like solution occurred by different mechanisms and extents due to the different structural chemistry of the variously doped apatites. Nevertheless, all the apatites synthesized in this work exhibited in vitro bioactivity demonstrating their potential use to develop biomedical devices with anti-osteoporotic functionality. - Highlights: • Biomimetic nanocrystalline apatites co-substituted with Mg, CO{sub 3} and Sr were prepared. • Biological-like amounts of Mg and CO{sub 3} were inserted to mimic the composition of bone apatite. • The addition of increasing

  3. The shape of ion tracks in natural apatite

    Energy Technology Data Exchange (ETDEWEB)

    Schauries, D., E-mail: daniel.schauries@anu.edu.au [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Afra, B.; Bierschenk, T. [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Lang, M. [Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Rodriguez, M.D. [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Trautmann, C. [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Technische Universität Darmstadt, 64287 Darmstadt (Germany); Li, W.; Ewing, R.C. [Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Kluth, P. [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia)

    2014-05-01

    Small angle X-ray scattering measurements were performed on natural apatite of different thickness irradiated with 2.2 GeV Au swift heavy ions. The evolution of the track radius along the full ion track length was estimated by considering the electronic energy loss and the velocity of the ions. The shape of the track is nearly cylindrical, slightly widening with a maximum diameter approximately 30 μm before the ions come to rest, followed by a rapid narrowing towards the end within a cigar-like contour. Measurements of average ion track radii in samples of different thicknesses, i.e. containing different sections of the tracks are in good agreement with the shape estimate.

  4. Biomimetic synthesis of calcium-strontium apatite hollow nanospheres

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this work,calcium-strontium apatite (Sr-HA) hollow nanospheres were synthesized by a facile biomimetic method.The structure and property of Sr-HA were characterized by FESEM,TEM,HRTEM,XRD and FT-IR spectroscopy.The influences of different ratios of calcium and strontium on the morphologies of the Sr-HA products were investigated.The experimental results revealed that the hollow spherical Sr-HA,with a size of 30-120 nm in diameter,could be synthesized when the molar ratio of Ca/Sr was 1:1.The possible formation mechanism of the hollow Sr-HA was proposed.The drug release experiments indicated that the hollow spherical Sr-HA had the property of sustained release.

  5. Radionuclide Incorporation and Long Term Performance of Apatite Waste Forms

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jianwei [Louisiana State Univ., Baton Rouge, LA (United States); Lian, Jie [Rensselaer Polytechnic Inst., Troy, NY (United States); Gao, Fei [Univ. of Michigan, Ann Arbor, MI (United States)

    2016-01-04

    This project aims to combines state-of-the-art experimental and characterization techniques with atomistic simulations based on density functional theory (DFT) and molecular dynamics (MD) simulations. With an initial focus on long-lived I-129 and other radionuclides such as Cs, Sr in apatite structure, specific research objectives include the atomic scale understanding of: (1) incorporation behavior of the radionuclides and their effects on the crystal chemistry and phase stability; (2) stability and microstructure evolution of designed waste forms under coupled temperature and radiation environments; (3) incorporation and migration energetics of radionuclides and release behaviors as probed by DFT and molecular dynamics (MD) simulations; and (4) chemical durability as measured in dissolution experiments for long term performance evaluation and model validation.

  6. Magnetic apatite for structural insights on the plasma membrane

    International Nuclear Information System (INIS)

    The iron oxide-hydroxyapatite (FeOxHA) nanoparticles reported here differ from those reported before by their advantage of homogeneity and simple preparation; moreover, the presence of carboxymethyldextran (CMD), together with hydroxyapatite (HA), allows access to the cellular membrane, which makes our magnetic apatite unique. These nanoparticles combine magnetic behavior, Raman label ability and the property of interaction with the cellular membrane; they therefore represent an interesting material for structural differentiation of the cell membrane. It was observed by Raman spectroscopy, scanning electron microscopy (SEM) and fluorescence microscopy that FeOxHA adheres to the plasma membrane and does not penetrate the membrane. These insights make the nanoparticles a promising material for magnetic cell sorting, e.g. in microfluidic device applications. (paper)

  7. In vitro effect of magnesium inclusion in sol-gel derived apatite

    International Nuclear Information System (INIS)

    Magnesium-containing apatite coatings were prepared on Ti6Al4V substrates by sol-gel dip coating method. Standard simulated body fluid (SBF) was used to evaluate the bioactivity of the coatings. A series of the coatings according to the composition (Ca10-xMgx)(PO4)6(OH)2, where x = 0 to 2, is synthesized and immersed in the standard SBF for periods of 7 to 35 days for direct deposition of apatite layer from the SBF solution. Scanning electron microscopy (SEM) was used to examine the morphology changes of the SBF apatite layer that occurred during in vitro immersion. X-ray diffractometry, Fourier Transformation Infra-Red Spectroscopy and X-ray Photoelectron Spectroscopy were used to analyse the phases, chemical groups and composition of the sol-gel coating. Results show that as the sol-gel coating contains magnesium, this promotes deposition of apatite layer from SBF. As x ≤ 1, SBF immersion gives rise to a dense apatite layer. However, as x >> 1, selected dissolution of the deposited layer takes place, which results in serious pitting on the surface. Also, Mg ions from the dissolution of the sol-gel coating during immersion in the SBF apparently played a role in the subsequent deposition of apatite o the coating, evidence of Mg was found in the apatite layer

  8. Mineralogical and geochemical studies on apatites and phosphate host rocks of Esfordi deposit, Yazd province, to determine the origin and geological setting of the apatite

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Rajabzadeh

    2014-10-01

    Full Text Available Introduction Iron-apatite ore deposits well known as Kiruna iron type formed in association with calc-alkaline volcanism from Proterozoic to Tertiary (Hitzman et al., 1992. Liquid immiscibility in an igneous system was proposed to explain the formation of the iron oxides accompanying apatite in mineralized zones (Förster and Jafarzadeh, 1994; Daliran, 1999. The mode of ore formation however, is a matter in debate. Bafq region in Central Iran is one of the greatest iron mining regions in Iran with 750 million tons of reservoir. The majority of the iron deposits contains apatite as minor mineral and underwent metamorphism-alteration in varying degrees. The mode of formation and geological setting of Esfordi iron-apatite deposit in this region with an average of 13.9 wt% apatite are discussed using geochemical and mineralogical data along with field description. Materials and methods Fifty-three samples of mineralized zones and host rocks collected from 7 cross sections were studied by conventional microscopic methods. Seven representative samples were determined by XRD at Department of Physics, Shiraz University. Fifteen and six samples were also analyzed for major and trace elements using XRF at Binaloud Co. Iran, and ICP-MS at Labwest Minerals Analysis, Australia, respectively. Microprobe analyses were carried out on apatite in Geo Forschungs Zentrum Telegrafenberg at Potsdam University, Germany. Results Field observation shows that igneous host rocks in Esfordi were intensively altered by hydrothermal fluids. The ores are surrounded by wide altered halos. Petrographic investigation indicated that the most important alterations are of potassic, carbonatitic and silicification types. Magnetite and apatite occur as major minerals, accompanied by minor hematite and goethite in the mineralized zones. Rare Earth Element (REE minerals are present as minor phases in the ores. Three apatite mineralization types (vein, massive, and disseminated were

  9. Adsorption of nucleotides on biomimetic apatite: The case of adenosine 5‧ monophosphate (AMP)

    Science.gov (United States)

    Hammami, K.; Feki, H. El; Marsan, O.; Drouet, C.

    2015-10-01

    This work investigates the interaction between the nucleotide adenosine 5‧ monophosphate molecule (AMP) and a biomimetic nanocrystalline carbonated apatite as a model for bone mineral. The analogy of the apatite phase used in this work with biological apatite was first pointed out by complementary techniques. AMP adsorption isotherms were then investigated. Obtained data were fitted to a Sips isotherm with an exponent greater than one suggesting positive cooperativity among adsorbed molecules. The data were compared to a previous study relative to the adsorption of another nucleotide, cytidine monophosphate (CMP) onto a similar substrate, evidencing some effect of the chemical nature of the nucleic base. An enhanced adsorption was observed under acidic (pH 6) conditions as opposed to pH 7.4, which parallels the case of DNA adsorption on biomimetic apatite. An estimated standard Gibbs free energy associated to the adsorption process (ΔG°ads ≅ -22 kJ/mol) intermediate between "physisorption" and "chemisorption" was found. The analysis of the solids after adsorption pointed to the preservation of the main characteristics of the apatite substrate but shifts or enhancements of Raman bands attributed to AMP showed the existence of chemical interactions involving both the phosphate and adenine parts of AMP. This contribution adds to the works conducted in view of better understanding the interaction of DNA/RNA and their constitutive nucleotides and the surface of biomimetic apatites. It could prove helpful in disciplines such as bone diagenesis (DNA/apatite interface in aged bones) or nanomedicine (setup of DNA- or RNA-loaded apatite systems). Also, the adsorption of nucleic acids on minerals like apatites could have played a role in the preservation of such biomolecules in the varying conditions known to exist at the origin of life on Earth, underlining the importance of dedicated adsorption studies.

  10. Fission-track dating of apatite from deep borehole ATK-1 at Atikokan, Ontario

    International Nuclear Information System (INIS)

    Fission-track age and lengths have been determined on apatite separated from core recovered from the ATK-1 deep borehole at Atikokan, Ontario. The apatite ages decrease down the borehole, from 515 ± 72 Ma at the top to 376 ± 46 Ma at a depth of 993 m. The mean confined track length for fossil fission tracks in the apatite is 12.4 μm. Within the limits of the measurement the track lengths are the same for all the samples. The results of this study indicate that the rocks found currently at the surface have never been heated above ∼100C since Upper Cambrian time

  11. Structure and Phase State of Bone Apatite of Calcified Aortic Fragments with Osteoporosis

    Directory of Open Access Journals (Sweden)

    Ya.V. Khyzhnya

    2013-10-01

    Full Text Available The paper represents the results of the study on the structure and phase composition of bone apatite and fragments of calcified aorta of the same experimental animal with model osteoporosis. Examination by the X-ray and electron diffraction, electron microscopy and infrared spectroscopy reveals that pathological calcification of rabbit aorta with model osteoporosis in crystal-chemical terms is the imperfect calcium apatite Ca10(PO46(OH2. Temperature growth of ectopic apatite crystals during annealing at 900C is similar to bioapatite of bone.

  12. Using Oxygen Isotopes in Fish Scale Apatite to Reconstruct Past Temperatures and Water Isotope Ratios

    Science.gov (United States)

    Lambert, T. D.; Paytan, A.

    2009-12-01

    Oxygen isotope ratios (δ18O) of apatite phosphate in fish bones and teeth vary according to the temperature and δ18O of water during formation. Since isotope ratios in apatite are often well preserved over geologic timescales, fish bones and teeth have been used to determine past environmental conditions. Fish scales offer several advantages over bones and teeth: they are relatively common in certain sedimentary basins, and they are more easily identified to species level. Analysis of paired bone and scale samples will be presented. The data indicate that fish scale apatite similarly records environmental conditions during growth. Thus δ18O of apatite phosphate in fish scales may provide useful paleoecological information and also indicate past environmental conditions.

  13. Preparation of Laminin-apatite-polymer Composites Using Metastable Calcium Phosphate Solutions

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A synthetic polymer with a laminin-apatite composite layer on its surface would be useful as a percutaneous device. The preparation of such a composite was attempted in the present study using poly ( ethylene terephthalate ) (PET) and polyethylene ( PE ) as the synthetic polymer. PET and PE plates and those pretreated with an oxygen plasma were alternately dipped in calcium and phosphate ion solutions, and then immersed in a metastable ealcium phosphate solution supplemented with laminin ( LCP solution ). The PET and PE plates pretreated with an oxygen plasma formed a uniform and continuous layer of a laminin- apatite composite on their surfaces. In contrast, the PET and PE plates that had not been pretreated with an oxygen plasma did not form a continuous layer of a laminin-apatite composite on their surfaces. The hydrophilic functional groups on the PET and PE surfaces introduced by the plasma treatment were responsible for the successful laminin-apatite composite coating.

  14. Geochemistry and genesis of apatite bearing Fe oxide Dizdaj deposit, SE Zanjan

    Directory of Open Access Journals (Sweden)

    Ghasem Nabatian

    2009-09-01

    Full Text Available Sorkheh-Dizaj apatite-iron oxide deposit is located 32 km southeast of Zanjan. The area is situated within the Tarom subzone of Western Alborz-Azarbaijan structural zone. The oldest units at the Sorkheh-Dizaj area are Eocene trachyte, trachyandesite, olivine basalt and volcanoclastic brecciate tuff and lapilli tuff which intruded by a quartz-monzonite, monzonite and granite subvolcanic pluton of Upper Eocene- Early Oligocene age. Subvolcanic plutonic rocks in the area show characteristics of the I-type granites. Magmatism of the area is of synorogenic to postorogenic related to magmatic arc environments. Mineralization at the area is divided into three main zones (A, B and C that all of which are located in the host subvolcanic pluton. These three zones are similar in terms of host rock, mineralogy, alteration, structure, texture and metal content. Mineralization in the volcanic rocks occurs as veins similar to those in three main zones, but less abundant. Geometry of the ore bodies is of vein type and their textures are stockwork, massive, banded, brecciate and vein-veinlet. The most important minerals at Sorkheh-Dizaj deposit are magnetite (low Ti and apatite that associated with them minor sulfide minerals such as chalcopyrite, bornite and pyrite. Minerals such as ilmenite, spinel (titanium magnetite, galena and sphalerite occur in low contents. The supergene minerals like chalcocite, malachite, azurite, covellite, hematite and goethite have been formed due to weathering and supergene processes. The main alterations at the deposit are K-feldspar metasomatism, actinolitization, argillic, sericitization, silicification, tourmalinization, and chlorite-epidotic. Rare earth elements (REE studies demonstrate that the deposit is more enriched in LREE than in HREE. The REE patterns in the apatite, magnetite and host rocks are similar suggesting a magmatic relationship. The REE contents of the apatites are higher than those of the host rocks and

  15. Influence of Microstructure and Sintering Routes on Transport Properties of Apatite Materials for Fuel Cells

    Institute of Scientific and Technical Information of China (English)

    A.Chesnaud; C.Estournes; G.Dezannau

    2007-01-01

    1 Results Oxy-apatite materials are thought as zirconia-substitutes in Solid Oxide Fuel Cells due to their fast ionic conduction. However, the well known difficulties related to their densification prevent them from being used as such. This study presents strategies to obtain oxy-apatite dense materials and the influence of elaboration route on transport properties. Particular emphasis is put on the microstructure effect on ion conduction. By the combined use of freeze-drying and conventional or spark p...

  16. Failure of a Glass Ionomer to Remineralize Apatite-depleted Dentin

    OpenAIRE

    Kim, Y. K.; Yiu, C.K.Y.; Kim, J.R.; Gu, L; Kim, S. K.; Weller, R.N.; Pashley, D.H.; Tay, F.R.

    2010-01-01

    Remineralization of demineralized dentin lesions adjacent to glass-ionomer cements (GICs) has been reported in the literature. This study tested the hypothesis that a strontium-based GIC can remineralize completely demineralized dentin by nucleation of new apatite crystallites within an apatite-free dentin matrix. Human dentin specimens were acid-etched, bonded with Fuji IX GP, and immersed in a calcium-and-phosphate-containing 1.5X simulated body fluid (SBF) for 1-4 months. Polyacrylic acid ...

  17. Fluoride enhances transfection activity of carbonate apatite by increasing cytoplasmic stability of plasmid DNA

    International Nuclear Information System (INIS)

    Highlights: → Cytoplasmic stability of plasmid DNA is enhanced by fluoride incorporation into carbonate apatite carrier. → Fluoridated carbonate apatite promotes a robust increase in transgene expression. → Controlled dissolution of fluoridated carbonate apatite in endosomal acidic environment might buffer the endosomes and prevent degradation of the released DNA. -- Abstract: Intracellular delivery of a functional gene or a nucleic acid sequence to specifically knockdown a harmful gene is a potential approach to precisely treat a critical human disease. The intensive efforts in the last few decades led to the development of a number of viral and non-viral synthetic vectors. However, an ideal delivery tool in terms of the safety and efficacy has yet to be established. Recently, we have developed pH-sensing inorganic nanocrystals of carbonate apatite for efficient and cell-targeted delivery of gene and gene-silencing RNA. Here we show that addition of very low level of fluoride to the particle-forming medium facilitates a robust increase in transgene expression following post-incubation of the particles with HeLa cells. Confocal microscopic observation and Southern blotting prove the cytoplasmic existence of plasmid DNA delivered by likely formed fluoridated carbonate apatite particles while degradation of plasmid DNA presumably by cytoplasmic nucleases was noticed following delivery with apatite particles alone. The beneficial role of fluoride in enhancing carbonate apatite-mediated gene expression might be due to the buffering potential of generated fluoridated apatite in endosomal acidic environment, thereby increasing the half-life of delivered plasmid DNA.

  18. Biomimetic coating of apatite/collagen composite on poly L-lactic acid facilitates cell seeding

    OpenAIRE

    Chen, Y; Mak, AFT; Wang, M; Li, J.

    2005-01-01

    Collagen and apatite were co-precipitated as a composite coating on poly L-lactic acid (PLLA) in an accelerated biomimetic process. The coating formed on PLLA films after 24 hours incubation was characterized. Saos-2 osteoblast-like cells were used to evaluate the cell seeding on this biomimetic composite coating. It was shown that cell seeding on PLLA films with the composite coating was greatly improved. PLLA coated with submicron collagen fibrils and submicron apatite paticulates can facil...

  19. Track shapes, etching characteristics and track density distribution on different planes of apatite

    International Nuclear Information System (INIS)

    Studies concerning track shapes, etching characteristics and track density of fission particle tracks due to the spontaneous fission of uranium along various crystallographic planes of apatite are presented. The studies were carried out on large complete crystals as well as on small grains of apatite belonging to various geological origins. Three track types (hexagonal, pyramidal and needle type) have been identified along various crystallographic planes. (author)

  20. Revisiting carbonate quantification in apatite (bio)minerals: a validated FTIR methodology

    OpenAIRE

    Grunenwald, Anne; Keyser, Christine; Sautereau, Anne-Marie; Crubézy, Eric; Ludes, Bertrand; Drouet, Christophe

    2014-01-01

    International audience Carbonated apatites represent an important class of compounds encountered in many fields including anthropology, archeology, geology, medicine and biomaterials engineering. They constitute, in particular, the mineral part of bones and teeth, are found in sedimentary settings, and are used as biomimetic compounds for the development of bone tissue engineering scaffolds. Whether for assessing the degree of biomimetism of synthetic apatites or for better understanding d...

  1. Fluoride enhances transfection activity of carbonate apatite by increasing cytoplasmic stability of plasmid DNA

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhury, E.H., E-mail: md.ezharul.hoque@med.monash.edu.my [Jeffrey Cheah School of Medicine and Health Sciences, Monash University Sunway Campus, Jalan Lagoon Selatan, Bandar Sunway, Selangor Darul Ehsan (Malaysia)

    2011-06-17

    Highlights: {yields} Cytoplasmic stability of plasmid DNA is enhanced by fluoride incorporation into carbonate apatite carrier. {yields} Fluoridated carbonate apatite promotes a robust increase in transgene expression. {yields} Controlled dissolution of fluoridated carbonate apatite in endosomal acidic environment might buffer the endosomes and prevent degradation of the released DNA. -- Abstract: Intracellular delivery of a functional gene or a nucleic acid sequence to specifically knockdown a harmful gene is a potential approach to precisely treat a critical human disease. The intensive efforts in the last few decades led to the development of a number of viral and non-viral synthetic vectors. However, an ideal delivery tool in terms of the safety and efficacy has yet to be established. Recently, we have developed pH-sensing inorganic nanocrystals of carbonate apatite for efficient and cell-targeted delivery of gene and gene-silencing RNA. Here we show that addition of very low level of fluoride to the particle-forming medium facilitates a robust increase in transgene expression following post-incubation of the particles with HeLa cells. Confocal microscopic observation and Southern blotting prove the cytoplasmic existence of plasmid DNA delivered by likely formed fluoridated carbonate apatite particles while degradation of plasmid DNA presumably by cytoplasmic nucleases was noticed following delivery with apatite particles alone. The beneficial role of fluoride in enhancing carbonate apatite-mediated gene expression might be due to the buffering potential of generated fluoridated apatite in endosomal acidic environment, thereby increasing the half-life of delivered plasmid DNA.

  2. Lanthanum germanate-based apatites as electrolyte for SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Marrero-Lopez, D.; Diaz-Carrasco, P.; Ramos-Barrado, J.R. [Departamento de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain); Pena-Martinez, J. [Instituto de Energias Renovables, Parque Tecnologico, Universidad de Castilla La Mancha, 02006 Albacete (Spain); Ruiz-Morales, J.C. [Departamento de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain)

    2011-02-15

    Germanate apatites with composition La{sub 10-x}Ge{sub 5.5}Al{sub 0.5}O{sub 26.75-3x/2} have been evaluated for the first time as possible electrolytes for solid oxide fuel cells (SOFCs). Different electrode materials have been considered in this study, i.e. manganite, ferrite, nickelates and cobaltite as cathode materials; and NiO-CGO composite and chromium-manganite as anodes. The chemical compatibility and electrochemical performance of these electrodes with La{sub 9.8}Ge{sub 5.5}Al{sub 0.5}O{sub 26.45} have been studied by X-ray powder diffraction (XRPD) and impedance spectroscopy. The XRPD analysis did not reveal appreciable bulk reactivity with the formation of reaction products between the germanate electrolyte and these electrodes up to 1,200 C. However, a significant cation interdiffusion was observed by energy dispersive spectroscopy (EDS) at the electrode/electrolyte interface, which leads to a significant decrease of the performance of these electrodes. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Electrical properties of iron doped apatite-type lanthanum silicates

    Institute of Scientific and Technical Information of China (English)

    SHI Qingle; ZHANG Hua

    2012-01-01

    The effect of Fe doping on the electrical properties of lanthanum silicates was investigated.The apatite-type lanthanum silicates La10Si6-xFexO27-x/2 (x=0.2,0.4,0.6,0.8,1.0) were synthesized via sol-gel process.The unit cell volume increased with Fe doping because the ionic radius of Fe3+ ion is larger than that of Si4+ ion.The conductivities of La10Si6-xFexO27 x/2 first increased and then decreased with the increasing of Fe content.The increase of the conductivity might be attributed to the distortion of the cell lattice,which assisted the migration of the interstitial oxygen ions.The decrease of the conductivity might be caused by the lower concentration of interstitial oxygen ions.The optimum Fe doping content in lanthanum silicates was 0.6.La10Si5.4Fe0.6O26.7 exhibited the highest ionic conductivity of 2.712× 10-2 S/cm at 800 ℃.The dependence of conductivity on oxygen partial pressure p(O2) suggested that the conductivity of La10Si6-xFexO27-x/2 was mainly contributed by ionic conductivity.

  4. Genesis of iron-apatite ores in Posht-e-Badam Block (central Iran) using REE geochemistry

    Indian Academy of Sciences (India)

    Mir Ali Asghar Mokhtari; Ghader Hossein Zadeh; Mohamad Hashem Emami

    2013-06-01

    Rare earth elements in apatites of different ore types show characteristic patterns which are related to different modes of formation of the ores. Most of the apatite-bearing iron ores are associated with alkaline magmas with LREE/HREE fractionation varying from moderate to steep. Iron-apatite deposits in Posht-e-Badam Block (Central Iran) have a high concentration of REE (more than 1000 ppm up to 2.5%), and show a strong LREE/HREE ratio with a pronounced negative Eu anomaly. This REE pattern is typical of magmatic apatite and quiet distinct from sedimentary apatites (phosphorites) which have a low REE contents and Ce negative anomalies. On the other hand, they are comparable to the REE patterns of apatites in Kiruna-type iron ores in different parts of the world. The REE patterns of apatites, iron-apatite ores and iron ores are similar and only have different REE contents. This similarity indicates a genetic relation for these rocks. Most of the iron-apatite deposits in Central Iran have similar REE patterns too, which in turn show a genetic relation for all of these deposits. This similarity indicates a similar origin and processes in their genesis. There are some small intrusions around some of the iron-apatite deposits that are petrographically identified as syenite and gabbro. These intrusions also have REE patterns similar to that of iron-apatite ores. This demonstrates a genetic relation between these intrusions and iron-apatite ores. The REE patterns of apatites in different deposits of Posht-e-Badam Block iron-apatite ores show an affinity to alkaline to sub-alkaline magmas and rifting environment. The alkaline host rocks of Central Iran iron-apatite ores are clearly related to an extensional setting where rifting was important (SSE–NNW fault lines). A probable source for this large scale ore forming processes is relatively low partial melting of mantle rocks. The ores have originated by magmatic differentiation as a late phase in the volcanic cycle

  5. The kinetics of alpha-decay-induced amorphization in zircon and apatite containing weapons-grade plutonium or other actinides

    International Nuclear Information System (INIS)

    Zircon and apatite form as actinide host phases in several high-level waste forms and have been proposed as host phases for the disposition of excess weapons-grade Pu and other actinides. Additionally, closely-related structure types appear as actinide-bearing phases among the corrosion products of spent nuclear fuel and high-level waste glasses. Self-radiation damage from α-decay of the incorporated Pu or other actinides can affect the durability and performance of these actinide-bearing phases. For both zircon and apatite, these effects can be modeled as functions of storage time and repository temperature and validated by comparison with data from natural occurrences. Natural zircons and apatites, with ages up to 4 billion years, provide abundant evidence for their long-term durability because of their wide spread use in geochronology and fission-track dating. Detailed studies of natural zircons and apatites, 238Pu-containing zircon, a 244Cm-containing silicate apatite, and ion-irradiated zircon, natural apatite and synthetic silicate apatites provide a unique basis for the analysis of α-decay effects over broad time scales. Models for α-decay effects in zircon and apatite are developed that show α-decay of Pu and other actinides will lead to a crystalline-to-amorphous transformation in zircon, but not in apatite, under conditions typical of a repository, such as the Yucca Mountain site. (orig.)

  6. Xe- and U-tracks in apatite and muscovite near the etching threshold

    International Nuclear Information System (INIS)

    Ion irradiation of a wedge-shaped Durango apatite backed by a mica detector allows investigating ion track ranges and etching properties at different points along the tracks. Transmission profiles obtained by irradiation with 2 × 106 cm−2 11.1 MeV/amu 132Xe and 2 × 106 cm−2 11.1 MeV/amu 238U parallel to the apatite c-axis correspond to ranges calculated with SRIM (Xe: 76.3 μm; U: 81.1 μm). However, the measured profiles show much greater etchable track-length variations than the calculated longitudinal straggles. The probable cause is that the length deficit exhibits significant variation from track to track. The measured length deficit in muscovite is in agreement with most existing data. In contrast, the length deficit in apatite appears to be close to zero, which is in conflict with all earlier estimates. This probably results from the etching properties of the apatite basal face, which permit surface-assisted sub-threshold etching of track sections in the nuclear stopping regime. These sections are not accessible from the opposite direction, i.e. by etching towards the endpoint of the tracks or in the direction of the ion beam. This conclusion is supported by the fact that linear dislocations are revealed in apatite basal faces and by the observation of imperfect etch pits that are separated from the etched ion track channel by a section that appears unetched under the microscope

  7. Bio-inspired citrate functionalized apatite coating on rapid prototyped titanium scaffold

    International Nuclear Information System (INIS)

    Highlights: • Designed and reproducible porous titanium scaffolds were produced. • Hydrophilic nanoporous film was built on scaffold. • Apatite coating was deposited on scaffold under the modulation of citrate ions. • Citrate ions could affect CO32− incorporation in apatite coatings. - Abstract: Scaffold functionalized with appropriate osteogenic coatings can significantly improve implant-bone response. In this study, with designed model and optimized manufacture parameters, reproducible and precise titanium scaffolds were produced. Reconstructed three-dimensional image and sectional structure of the scaffold were examined by micro-computed tomography and relative software. Alkali treatment was carried out on these manufactured porous scaffolds to produce nanoporous hydrophilic film. After 6 days deposition in simulated body fluid (SBF) containing sodium citrate (SC-SBF), plate-like amorphous calcium phosphate (ACP) coating was deposited on scaffold surface. Ultrasonication tests qualitatively indicated an enhanced adhesion force of apatite coatings deposited in SC-SBF compared to that deposited in SBF. And the effect of citrate ions on the CO32− incorporation rate in apatite coating was quantitatively examined by bending vibration of CO32− at ∼874 cm−1. Results indicated the highest carbonate content was obtained at the citrate ion concentration of 6 × 10−5 mol/L in SC-SBF. These three-dimensional porous titanium-apatite hybrid scaffolds are expected to find application in bone tissue regeneration

  8. Microwave assisted apatite coating deposition on Ti6Al4V implants

    International Nuclear Information System (INIS)

    In this work we report a novel microwave assisted technology to deposit a uniform, ultra-thin apatite coating without any cracks on titanium implants in minutes. This method comprises of conventional biomimetic coating in synergism with microwave irradiation to result in alkaline earth phosphate nucleation. The microwave assisted coating process mainly follows the initial stages of biomimetic coating until the step of the Ca-P nuclei formation. After that, due to microwave irradiation more Ca-P nuclei are formed to cover the whole surface of the implant instead of the growth of deposited Ca-P nuclei to Ca-P globules and coatings. It is interesting to note the doping of Mg2+ to Ca-P apatite coating can significantly change the properties and performances of as-deposited coatings. The hydrophilicity, physical properties, bioactivity, cell adhesion, and growth capability of as-deposited microwave assisted coatings were investigated. The study shows that this coating technology has great potential in biomedical applications. Additionally, since biomimetic coating can be applied to series of implant materials such as polymer, metals and glass, it is expected this microwave assisted coating technology can also be applied to these materials if they can remains stable at 100 °C, the boiling point of water. - Highlights: • A microwave assisted apatite coating process. • Apatite composition can be controlled by adjusting solution composition. • The deposited apatite coating is uniform, non-crack, and ultra-thin. • The coating process takes only a few minutes

  9. Fabrication and apatite inducing ability of different porous titania structures by PEO treatment.

    Science.gov (United States)

    Rao, X; Chu, C L; Sun, Q; Zheng, Y Y

    2016-09-01

    Plasma electrolytic oxidation (PEO) was employed to grow different porous titania structures on Ti6Al4V alloy (TC4) substrate using various parameters. It was found that the PEO voltage and working frequency could affect the morphology, the pore size, the pore density, the thickness and the phase composition of titania structures. Thereafter, three typical porous titania structures with nanosize pores, microsize pores and microsize grooves were respectively selected to estimate their bioactivity using SBF immersion test. After soaking at different durations (3-28d), the surface morphology, the chemical composition as well as the phase structure of deposited apatite layers on porous titania were evaluated using SEM, EDS, and XRD. The formation of various biomimetic apatite layers indicated the different influence due to the characteristics of porous titania structures. The porous titania structure with nanosize pores could induce a fast apatite growth at the early immersion stage (~7d), while the one with microsize pores exhibited the best apatite inducing ability at long term immersion (~28d). Based on the experimental results, the formation mechanism of biomimetic apatite affected by the pore structure of titania was discussed as well. PMID:27207066

  10. Challenges Associated with Apatite Remediation of Uranium in the 300 Area Aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Wellman, Dawn M.; Fruchter, Jonathan S.; Vermeul, Vincent R.; Williams, Mark D.

    2008-05-01

    Sequestration of uranium as insoluble phosphate phases appears to be a promising alternative for treating the uranium-contaminated groundwater at the Hanford 300 Area. The proposed approach involves both the direct formation of autunite by the application of a polyphosphate mixture, as well as the formation of apatite in the aquifer as a continuing source of phosphate for long-term treatment of uranium. After a series of bench-scale tests, a field treatability test was conducted in a well at the 300 Area. The objective of the treatability test was to evaluate the efficacy of using polyphosphate injections to treat uranium-contaminated groundwater in situ. A test site consisting of an injection well and 15 monitoring wells was installed in the 300 Area near the process trenches that had previously received uranium-bearing effluents. The results indicated that while the direct formation of autunite appears to have been successful, the outcome of the apatite formation of the test was more limited. Two separate overarching issues impact the efficacy of apatite remediation for uranium sequestration within the 300 Area: 1) the efficacy of apatite for sequestering uranium under the present geochemical and hydrodynamic conditions, and 2) the formation and emplacement of apatite via polyphosphate technology. This paper summarizes these issues.

  11. Enamel-like apatite crown covering amorphous mineral in a crayfish mandible.

    Science.gov (United States)

    Bentov, Shmuel; Zaslansky, Paul; Al-Sawalmih, Ali; Masic, Admir; Fratzl, Peter; Sagi, Amir; Berman, Amir; Aichmayer, Barbara

    2012-01-01

    Carbonated hydroxyapatite is the mineral found in vertebrate bones and teeth, whereas invertebrates utilize calcium carbonate in their mineralized organs. In particular, stable amorphous calcium carbonate is found in many crustaceans. Here we report on an unusual, crystalline enamel-like apatite layer found in the mandibles of the arthropod Cherax quadricarinatus (freshwater crayfish). Despite their very different thermodynamic stabilities, amorphous calcium carbonate, amorphous calcium phosphate, calcite and fluorapatite coexist in well-defined functional layers in close proximity within the mandible. The softer amorphous minerals are found primarily in the bulk of the mandible whereas apatite, the harder and less soluble mineral, forms a wear-resistant, enamel-like coating of the molar tooth. Our findings suggest a unique case of convergent evolution, where similar functional challenges of mastication led to independent developments of structurally and mechanically similar, apatite-based layers in the teeth of genetically remote phyla: vertebrates and crustaceans. PMID:22588301

  12. PNNL Apatite Investigation at 100-NR-2 Quality Assurance Project Plan

    Energy Technology Data Exchange (ETDEWEB)

    Fix, N. J.

    2009-04-02

    In 2004, the U.S. Department of Energy, Fluor Hanford, Inc., Pacific Northwest National Laboratory (PNNL), and the Washington Department of Ecology agreed that the long-term strategy for groundwater remediation at the 100-N Area would include apatite sequestration as the primary treatment, followed by a secondary treatment if necessary. Since then, the agencies have worked together to agree on which apatite sequestration technology has the greatest chance of reducing strontium-90 flux to the Columbia River. This Quality Assurance Project Plan provides the quality assurance requirements and processes that will be followed by staff working on the PNNL Apatite Investigation at 100-NR-2 Project. The plan is designed to be used exclusively by project staff.

  13. Carbon isotopes in eclogite and apatite separate from Huangzhen and Shima in SE Dabie

    Institute of Scientific and Technical Information of China (English)

    李一良; 郑永飞; 龚冰; 傅斌

    2000-01-01

    The carbon isotope compositions of high- and ultrahigh-pressure eclogite and apatite separate from Huangzhen and Shima in SE Dabie Mountains were analyzed by EA-MS online technique. The δ13C values of the eclogites cover a wide range of -30.7‰ - +1.5‰, whereasthose of apatites only have a small range of -28.1‰- -21.0‰. Some of the eclogites with thehigh δ13C values suffered retrogressive alteration by CO2-bearing fluids. The low δ13C values of the apatites indicate that the eclogites contain surficial carbon of organic origin. It is concluded that protoliths of the eclogites were exposed to the surface of the Earth, and that the carbon-bearing fluid was depleted in 13C during the eclogite-facies metamorphism.

  14. Carbon isotopes in eclogite and apatite separate from Huangzhen and Shima in SE Dabie

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The carbon isotope compositions of high- and ultrahigh-pressure eclogite and apatite separate from Huangzhen and Shima in SE Dabie Mountains were analyzed by EA-MS online technique. The δ13C values of the eclogites cover a wide range of -30.7‰ - +1.5‰, whereas those of apatites only have a small range of -28.1‰--21.0‰. Some of the eclogites with the high δ13C values suffered retrogressive alteration by CO2-bearing fluids. The low δ13C values of the apatites indicate that the eclogites contain surficial carbon of organic origin. It is concluded that protoliths of the eclogites were exposed to the surface of the Earth, and that the carbon-bearing fluid was depleted in 13C during the eclogite-facies metamorphism.

  15. Preliminary Apatite Fission Track Thermochronology of Wrangel Island, Arctic Russia

    Science.gov (United States)

    Dumitru, T. A.; Miller, E. L.

    2010-12-01

    Wrangel Island is part of a regional structural high that forms the continuation of the offshore Herald Arch and Chukchi Platform of Alaska. It is flanked on the north by the deep North Chukchi Basin, which in addition to Paleozoic strata, is inferred to contain up to 12 km of Beaufortian and Brookian (Late Jurassic to Tertiary) sediments (Dinkelman et al., 2008). To the south, ~E-W trending faults bound the Longa Basin that separates Wrangel from mainland Chukotka. This basin lies along strike of the early Tertiary Hope Basin in the Alaskan offshore. Wrangel Island itself exposes a broad, doubly-plunging anticlinorium-like structure cored by Neoproterozoic basement and flanked by Paleozoic shelf successions and a thick section of Triassic turbidites, representing about 5-7 km of structural section. The structural geology of Wrangel Island has been interpreted to represent a north-vergent Mesozoic fold and thrust belt linked by seismic reflection to the Herald Arch and then to the Lisburne Hills and the Brooks Range foreland fold and thrust belt (e.g. Kos’ko et al., 1993). However, deformation differs considerably from typical foreland fold-thrust structures of the Brooks Range as it is penetrative, involves large strains, and occurred under greenschist facies metamorphic conditions. Parts of the sequence exhibit mylonitic fabrics. Apatite fission track thermochronology of rocks from Wrangel Island can establishes the age of cooling to temperatures below ~ 100° C, providing temporal constraints on the uplift and erosional history of rocks that form this regional structural high. We analyzed seven fission track samples from a 9-km long N-S transect along the Kishchnikov River, from Triassic strata on the southern flank of the anticlinal structure to Devonian(?)-Mississippian feldspathic grits, conglomerates, and underlying Neoproterozoic igneous basement rocks in its core. All samples yielded statistically indistinguishable fission track ages averaging about 95

  16. Characterization of damaging in apatitic materials irradiated with heavy ions and thermally annealed

    International Nuclear Information System (INIS)

    Some minerals belonging to the family of apatite are seen to be potential candidates for use as conditioning matrices or transmutation targets for high level nuclear waste management. Indeed, studies of natural nuclear reactors (Oklo) highlighted the strong ability of these minerals to anneal irradiation damage. In order to determine the global behaviour of these materials, we performed a fundamental study on the evolution of irradiation damage induced by various heavy ions in two apatites: a natural phospho-calcic fluor-apatite from Durango and a synthetic sintered mono-silicated fluor-apatite, called britholite. The damage in these materials was measured by using channelling R.B.S. and X-ray diffraction respectively and by determining an amorphization effective radius Re. The results revealed a similar behaviour for both apatites according to the electronic energy deposit at the entrance of the material. In addition, the effect of an isothermal annealing at 300 C was quantified on a mono-silicated britholite previously irradiated with Kr ions. We highlighted in this case the return of the lattice parameters to their initial values, followed by a partial and slow rebuilding of the crystalline lattice versus the annealing time. Finally, we followed the changes in the morphology of etch pits in the Durango fluor-apatite after acid dissolution as a function of the energy deposit by the ions. We showed that the influence of crystallography leads quickly to opening angles close to 30 degrees. The calculation of etching velocities within the irradiated material highlighted that there is a range of deposit energy where the velocity ratio increases strongly before becoming constant. (author)

  17. Adsorption of nucleotides on biomimetic apatite: The case of adenosine 5‧ triphosphate (ATP)

    Science.gov (United States)

    Hammami, Khaled; El-Feki, Hafed; Marsan, Olivier; Drouet, Christophe

    2016-01-01

    ATP is a well-known energy supplier in cells. The idea to associate ATP to pharmaceutical formulations/biotechnological devices to promote cells activity by potentially modulating their microenvironment thus appears as an appealing novel approach. Since biomimetic nanocrystalline apatites have shown great promise for biomedical applications (bone regeneration, cells diagnostics/therapeutics, …), thanks to a high surface reactivity and an intrinsically high biocompatibility, the present contribution was aimed at exploring ATP/apatite interactions. ATP adsorption on a synthetic carbonated nanocrystalline apatite preliminarily characterized (by XRD, FTIR, Raman, TG-DTA and SEM-EDX) was investigated in detail, pointing out a good agreement with Sips isothermal features. Adsorption characteristics were compared to those previously obtained on monophosphate nucleotides (AMP, CMP), unveiling some specificities. ATP was found to adsorb effectively onto biomimetic apatite: despite smaller values of the affinity constant KS and the exponential factor m, larger adsorbed amounts were reached for ATP as compared to AMP for any given concentration in solution. m ATP/apatite adsorption process is mostly guided by direct surface bonding rather than through stabilizing intermolecular interactions. Although standard ΔGads ° was estimated to only -4 kJ/mol, the large value of Nmax led to significantly negative effective ΔGads values down to -33 kJ/mol, reflecting the spontaneous character of adsorption process. Vibrational spectroscopy data (FTIR and Raman) pointed out spectral modifications upon adsorption, confirming chemical-like interactions where both the triphosphate group of ATP and its nucleic base were involved. The present study is intended to serve as a basis for future research works involving ATP and apatite nanocrystals/nanoparticles in view of biomedical applications (e.g. bone tissue engineering, intracellular drug delivery, …).

  18. The study of geochemical behavior of rare earth elements in apatites from the Hormoz Island, Persian Gulf

    Directory of Open Access Journals (Sweden)

    Ali Rostami

    2014-04-01

    Full Text Available The study area is located about 3 km southwest of the Hormoz Island in the Hormozgan province, in the Persian Gulf. The main rock units in the region consist of a highly altered acidic pluton cratophyre, which is responsible for apatite formation, diabasic dike, marl and altered basalt. Apatite is the only phosphate mineral in the Hormoz Island, which has accumulated REE in its crystal structure. The amount of Na2O and SiO2 oxides in apatite are high and the average content of the main elements Fe, Mg, Al, Ca are 7.5 ppm, 365 ppm, 2880 ppm and 27.8%, respectively. The Y, Mn, Rb contents increase and Sr decreases with increasing magmatic differentiation. It shows that a moderate magmatic differentiation occurred during the crystallization of apatite. The total REE content in the Hormoz apatite is high (1.22-2.25%. LREE/HREE ratio is also high. This means that Hormoz apatites are enriched in light rare earth elements. The REE normalized pattern shows a negative slope with a negative Eu anomaly. According to various diagrams based on apatite composition, it is deduced that the Hormoz apatites belong to mafic I-type granitoids with high oxidation state (Fe2O3/FeO>1.

  19. Growth of apatite on chitosan-multiwall carbon nanotube composite membranes

    Energy Technology Data Exchange (ETDEWEB)

    Yang Jun; Yao Zhiwen [State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No 14, 3rd Section South People' s Road, Chengdu 610041 (China); Tang Changyu [Department of Polymer Science and Materials, Sichuan University (China); Darvell, B.W. [Dental Materials Science, Faculty of Dentistry, University of Hong Kong (Hong Kong); Zhang Hualin; Pan Lingzhan; Liu Jingsong [State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No 14, 3rd Section South People' s Road, Chengdu 610041 (China); Chen Zhiqing, E-mail: yangj0710@gmail.com [State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, No 14, 3rd Section South People' s Road, Chengdu 610041 (China)

    2009-07-30

    Bioactive membranes for guided tissue regeneration would be of value for periodontal therapy. Chitosan-multiwall carbon nanotube (CS-MWNT) composites were treated to deposit nanoscopic apatite for MWNT proportions of 0-4 mass%. Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, and X-ray diffraction were used for characterization. Apatite was formed on the CS-MWNT composites at low MWNT concentrations, but the dispersion of the MWNT affects the crystallite size and the Ca/P molar ratio of the composite. The smallest crystallite size was 9 nm at 1 mass% MWNT.

  20. Removal of cadmium, copper, nickel, cobalt and mercury from water by Apatite IITM: Column experiments

    International Nuclear Information System (INIS)

    Highlights: → The efficiency of Apatite IITM increases as the acidity decreases, then the application of apatite-based materials for metal removal treatments should be restricted to slightly acid to neutral waters. → Because of the preferred process of using phosphate ions to form metal-phosphate precipitates, the mixture with other sources of alkalinity, such as limestone, is proposed to extend the duration of Apatite IITM. → Compared with other reactive materials such as limestone and caustic magnesia that exhibit a reduction of porosity Apatite IITM showed stable hydraulic performance. → The extrapolation of the column durabilities to a 1-m-thick passive treatment suggests that the Apatite IITM filling can be active between 5 and 10 years for an inflow pH exceeding 5. - Abstract: Apatite IITM, a biogenic hydroxyapatite, was evaluated as a reactive material for heavy metal (Cd, Cu, Co, Ni and Hg) removal in passive treatments. Apatite IITM reacts with acid water by releasing phosphates that increase the pH up to 6.5-7.5, complexing and inducing metals to precipitate as metal phosphates. The evolution of the solution concentration of calcium, phosphate and metals together with SEM-EDS and XRD examinations were used to identify the retention mechanisms. SEM observation shows low-crystalline precipitate layers composed of P, O and M. Only in the case of Hg and Co were small amounts of crystalline phases detected. Solubility data values were used to predict the measured column experiment values and to support the removal process based on the dissolution of hydroxyapatite, the formation of metal-phosphate species in solution and the precipitation of metal phosphate. Cd5(PO4)3OH(s), Cu2(PO4)OH(s), Ni3(PO4)2(s), Co3(PO4)28H2O(s) and Hg3(PO4)2(s) are proposed as the possible mineral phases responsible for the removal processes. The results of the column experiments show that Apatite IITM is a suitable filling for permeable reactive barriers.

  1. Lead orthovanadate and some vanadium-lead compounds with the apatite structure

    International Nuclear Information System (INIS)

    The infrared and Raman spectra of Pb3(VO4)2 are recorded and discussed with the aid of the 'site symmetry' rules. The i.r. spectra of the compounds Pb5(VO4)3X (X=F, Cl, Br), Pb5(VO4)2GeO4, Pb5(VO4)2SiO4 (all with apatite structure) are also measured and briefly discussed. The X-ray, spectroscopic and analytical investigation of the lead vanadates precipitated from solutions, shows that in this cases mixed crystals of complicated nature, with the apatite structure, are obtained. (author)

  2. Effects of radiation damage on infra-red and thermoluminescence properties of natural apatites

    International Nuclear Information System (INIS)

    Thermoluminescence (TL) and infra-red (IR) spectra from various natural crystals of apatite have been examined. All naturally damaged samples (the amount of damage being monitored by their fossil fission track density) were found to exhibit a reduced contribution in the thermoluminescence glow intensity relative to that of undamaged one. Annealing the samples for 1 hour at temperatures above 500oC resulted in an increase in TL sensitivity. The investigation shows strong evidence that radiation damage is responsible for the reduced TL sensitivity. High uranium content in apatite sample shows an increasing IR peak intensity at 740 cm-1 with increasing annealing temperature. (Author)

  3. Pacific Northwest National Laboratory Apatite Investigation at the 100-NR-2 Quality Assurance Project Plan

    Energy Technology Data Exchange (ETDEWEB)

    Fix, N. J.

    2008-03-28

    This Quality Assurance Project Plan provides the quality assurance requirements and processes that will be followed by staff working on the 100-NR-2 Apatite Project. The U.S. Department of Energy, Fluor Hanford, Inc., Pacific Northwest National Laboratory, and the Washington Department of Ecology agreed that the long-term strategy for groundwater remediation at 100-N would include apatite sequestration as the primary treatment, followed by a secondary treatment. The scope of this project covers the technical support needed before, during, and after treatment of the targeted subsurface environment using a new high-concentration formulation.

  4. Feasibility of using natural fishbone apatite as a substitute for hydroxyapatite in remediating aqueous heavy metals.

    Science.gov (United States)

    Admassu, W; Breese, T

    1999-10-29

    Fishbone, a natural, apatite rich substance, was examined for suitability as a substitute for hydroxyapatite in the sequestering of aqueous divalent heavy metal ions. The fishbone exhibited lower metal removal capacity than pure hydroxyapatite, due primarily to its purity ( approximately 70% apatite equivalent). In other ways the fishbone behaves in a similar manner as pure hydroxyapatite in the sequestration process. It was observed that it can remove all Pb(2+), Cu(2+), Cd(2+) and Ni(2+) to below detectable levels as measured by inductively coupled plasma atomic absorption, and the rate of reaction with either Zn(2+), Ni(2+), or Pb(2+) was also found to be similar to hydroxyapatite. Also, a two level, three variable full factorial design was performed for the Pb/apatite reaction and both apatites performed similarly. The main difference, besides capacity, was on exposure to high (2.4 mM) Pb concentrations. The fishbone removed less of the Pb(2+) than capacity correction predicted. PMID:10536284

  5. Preparation of an apatite-based matrix for the confinement of iodine 129

    International Nuclear Information System (INIS)

    The aim of this thesis is the study of the conditioning of iodine 129 from the reprocessing of nuclear wastes. Because of its long half life (1.57 107 years), the conditioning of iodine 129 requires a matrix stable during several thousands of years. The study of natural minerals allows the selection of mineral phases having a good long term behaviour. In the first part the policy of nuclear wastes management, and in particular of iodine, is recalled. A naturalistic approach is used to define the best conditioning material and the remarkable properties of apatite in this way are described. In the second part, the preparation and physical-chemical characterization of iodo-apatites are described. A demonstration is made that iodine can penetrate inside vanadate or lead phospho-vanadate apatite-based compounds. The third part deals with the preparation of the conditioning material. The sintering reaction under pressure allows the preparation of composite ceramics including iodo-apatite. A multi-layer coating process is defined: coating of PbI2 with a Pb3(VO4)1.6(PO4)0.4 layer and a Ca10(PO4)6F2 layer. Sintering is performed at 700 deg. celsius under a 25 MPa pressure. (J.S.)

  6. Osteointegration of biomimetic apatite coating applied onto dense and porous metal implants in femurs of goats

    NARCIS (Netherlands)

    Barrere, F.; Valk, van der C.M.; Meijer, G.; Dalmeijer, R.A.J.; Groot, de K.; Layrolle, P.

    2003-01-01

    Biomimetic calcium phosphate (Ca-P) coatings were applied onto dense titanium alloy (Ti6Al4V) and porous tantalum (Ta) cylinders by immersion into simulated body fluid at 37 °C and then at 50 °C for 24 h. As a result, a homogeneous bone-like carbonated apatitic (BCA) coating, 30 m thick was deposite

  7. Adsorption of Pb(II) present in aqueous solution on calcium, strontium and barium hydroxy apatites

    International Nuclear Information System (INIS)

    Calcium, strontium and barium hydroxy apatites were successfully synthesized by chemical precipitation method, the obtained powders were characterized by the techniques of X-ray diffraction (XRD), scanning electron microscopy (Sem), semi-quantitative elemental analysis (EDS), infrared spectroscopy (IR), and N2 physisorption studies, complementary to these analytical techniques, was determined the surface fractal dimension (Df), and the amount of surface active sites of the materials, in order to know application as ceramic for water remediation. The ability of Pb(II) ion adsorption present in aqueous solution on the hydroxy apatites synthesized by batch type experiments was studied as a function of contact time, concentration of the adsorbate and temperature. The maximum lead adsorption efficiencies obtained were 0.31, 0.32 and 0.26 mg/g for calcium, strontium and barium hydroxy apatites respectively, achieved an equilibrium time of 20 minutes in the three solid-liquid systems studied. Experimental data were adequately adjusted at the adsorption kinetic model pseudo-second order, for the three cases. Moreover, experimental data of the strontium and calcium hydroxy apatites were adjusted to the Langmuir adsorption isotherm, indicating that the adsorption was through a monolayer, whereas barium hydroxyapatite was adjusted to the Freundlich adsorption isotherm, indicating a multilayer adsorption. The thermodynamic parameters obtained during adsorption studies as a function of temperature showed physisorption, exothermic and spontaneous processes respectively. The results showed that the calcium hydroxyapatite, strontium and barium are an alternative for the Pb(II) ion adsorption present in wastewaters. (Author)

  8. Preparation of fluoride substituted apatite cements as the building blocks for tooth enamel restoration

    Science.gov (United States)

    Wei, Jie; Wang, Jiecheng; Liu, Xiaochen; Ma, Jian; Liu, Changsheng; Fang, Jing; Wei, Shicheng

    2011-06-01

    Fluoride substituted apatite cement (fs-AC) was synthesized by using the cement powders of tetracalcium phosphate (TTCP) and sodium fluoride (NaF), and the cement powders were mixed with diluted phosphoric acid (H 3PO 4) as cement liquid to form fs-AC paste. The fs-AC paste could be directly filled into the carious cavities to repair damaged dental enamel. The results indicated that the fs-AC paste was changed into fluorapatite crystals with the atom molar ratio for calcium to phosphorus of 1.66 and the F ion amount of 3 wt% after self-hardening for 2 days. The solubility of fs-AC in Tris-HCl solution (pH 6) was slightly lower than hydroxyapatite cement (HAC) that was similar to the apatite in enamel, indicating the fs-AC was much insensitive to the weakly acidic solution than the apatite in enamel. The fs-AC was tightly combined with the enamel surface because of the chemical reaction between the fs-AC and the apatite in enamel after the caries cavities was filled with fs-AC. The extracts of fs-AC caused no cytotoxicity on L929 cells, which satisfied the relevant criterion on dental biomaterials, revealing good cytocompatibility. The fs-AC had potential prospect for the reconstitution of carious lesion of dental enamel.

  9. Adsorption/desorption of Direct Yellow 28 on apatitic phosphate: Mechanism, kinetic and thermodynamic studies

    Directory of Open Access Journals (Sweden)

    H. El Boujaady

    2014-10-01

    Full Text Available In this study, the adsorption potential of apatitic tricalcium phosphate for the removal of Direct Yellow 28 (DY28 from aqueous solution has been investigated by using batch mode experiments. The effects of different parameters such as pH, adsorbent dosage, initial dye concentration, contact time, addition of ions and temperature have been studied to understand the adsorption behavior of the adsorbent under various conditions. The adsorbent has been characterized by pHzpc measurement, chemical analyses, FTIR, XRD and TEM. The Langmuir and Freundlich models are found to be the best to describe the equilibrium isotherm data, with a maximum monolayer adsorption capacity of 67.02 mg g−1. Thermodynamic parameters including the Gibbs free energy ΔG, enthalpy ΔH, and entropy ΔS have revealed that the adsorption of DY28 on the apatitic tricalcium phosphate is feasible, spontaneous and endothermic. Among the kinetic models tested for apatitic tricalcium phosphate, the pseudo-second-order model fits the kinetic data well. The introduction of orthophosphate ions in the medium causes a decrease of adsorption. The addition of Ca2+ ions favors the adsorption. The results of this study have demonstrated the effectiveness and feasibility of the apatitic tricalcium phosphate for the removal of DY28 from aqueous solution.

  10. Chemical, physical, and histologic studies on four commercial apatites used for alveolar ridge augmentation

    DEFF Research Database (Denmark)

    Pinholt, E M; Ruyter, I E; Haanaes, H R; Bang, G

    1992-01-01

    The purpose of this study was to evaluate four commercial apatite products. Subperiosteal alveolar ridge augmentation was performed on the maxilla of rats by implantation of granules of two dense products and of two porous products, and the tissue response was compared with the material character...

  11. Synthesis and Characterization of Tb-incorporated Apatite Nano-scale Powders

    Institute of Scientific and Technical Information of China (English)

    L.J. Sun; P.F. Ni; D.G. Guo; C.Q. Fang; J. Wang; F. Yang; X.F. Huang; Y.Z. Hao; H. Zhu; K.W. Xu

    2012-01-01

    Nano-scale Tb-incorporated apatite (nano-Tb-AP) particles with different Tb contents (Tb/(Tb+Ca)) of 0%, 5%, 10% and 20% were synthesized through a simple wet chemical method in this study. The crystal structure, thermal stabilities, chemical groups, crystal morphologies and crystal sizes of the nano--Tb-AP particles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM), respectively. It was found that lattice constants, particle sizes, crystalline and thermal stability varied with the doped Tb contents. With the increasing of Tb content, the lattice constants, particle size, length/diameter ratio, crystalline and thermal stability of nano-Tb-AP gradually decrease. Especially, almost all the 20%Tb-AP nano particles had been decomposed at 1200 ℃ while only a few of the decomposed products (β-TCP) were detected in the Tb-free nano apatite powders: This kind of nano-scale Tb-incorporated apatite exhibits an extremely potential clinic application because it integrates both the excellent biological functions of Tb element and apatite in human body.

  12. Naturally etched tracks in apatites and the correction of fission track dating

    International Nuclear Information System (INIS)

    Naturally etched tracks have been found in apatites from the rapid cooled, high-level Kunon pluton in the Zhangzhou Igneous Complex, SE China. This is manifested by the fact that the apatite fission track (FT) age derived from conventional counting of spontaneous and induced tracks yields a result of 140.6±6.5 Ma, which is much older than the ages determined using other methods on different minerals from the same rock. When tracks are observed after etching the polished inner sections of the apatite grains, the naturally etched tracks characterized by having hazy boundaries can be distinguished from the normal tracks with sharp boundaries. The age obtained by omitting these fading-resistant hazy tracks, 76.5±4.0 Ma, indicates the time of the Kunon pluton cooling down to ∼100 deg. C. The corrected peak age (73.8 Ma) is consistent with the other apatite FT peak ages (79.2 to 70.2 Ma) of the nearly contemporaneous plutons in the same igneous complex

  13. Naturally etched tracks in apatites and the correction of fission track dating

    CERN Document Server

    Tien, J L

    1999-01-01

    Naturally etched tracks have been found in apatites from the rapid cooled, high-level Kunon pluton in the Zhangzhou Igneous Complex, SE China. This is manifested by the fact that the apatite fission track (FT) age derived from conventional counting of spontaneous and induced tracks yields a result of 140.6+-6.5 Ma, which is much older than the ages determined using other methods on different minerals from the same rock. When tracks are observed after etching the polished inner sections of the apatite grains, the naturally etched tracks characterized by having hazy boundaries can be distinguished from the normal tracks with sharp boundaries. The age obtained by omitting these fading-resistant hazy tracks, 76.5+-4.0 Ma, indicates the time of the Kunon pluton cooling down to approx 100 deg. C. The corrected peak age (73.8 Ma) is consistent with the other apatite FT peak ages (79.2 to 70.2 Ma) of the nearly contemporaneous plutons in the same igneous complex.

  14. Preparation of fluoride substituted apatite cements as the building blocks for tooth enamel restoration

    Energy Technology Data Exchange (ETDEWEB)

    Wei Jie [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Inter-disciplinary Studies, Peking University, Beijing 100871 (China); Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Wang Jiecheng; Liu Xiaochen [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Inter-disciplinary Studies, Peking University, Beijing 100871 (China); Ma Jian [Hospital of Stomatology, Tongji University, Shanghai 200072 (China); Liu Changsheng [Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Fang Jing, E-mail: biomater2006@yahoo.com.cn [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Inter-disciplinary Studies, Peking University, Beijing 100871 (China); Wei Shicheng, E-mail: nic7505@263.net [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Inter-disciplinary Studies, Peking University, Beijing 100871 (China) and School and Hospital of Stomatology, Peking University, Beijing 100081 (China)

    2011-06-15

    Fluoride substituted apatite cement (fs-AC) was synthesized by using the cement powders of tetracalcium phosphate (TTCP) and sodium fluoride (NaF), and the cement powders were mixed with diluted phosphoric acid (H{sub 3}PO{sub 4}) as cement liquid to form fs-AC paste. The fs-AC paste could be directly filled into the carious cavities to repair damaged dental enamel. The results indicated that the fs-AC paste was changed into fluorapatite crystals with the atom molar ratio for calcium to phosphorus of 1.66 and the F ion amount of 3 wt% after self-hardening for 2 days. The solubility of fs-AC in Tris-HCl solution (pH 6) was slightly lower than hydroxyapatite cement (HAC) that was similar to the apatite in enamel, indicating the fs-AC was much insensitive to the weakly acidic solution than the apatite in enamel. The fs-AC was tightly combined with the enamel surface because of the chemical reaction between the fs-AC and the apatite in enamel after the caries cavities was filled with fs-AC. The extracts of fs-AC caused no cytotoxicity on L929 cells, which satisfied the relevant criterion on dental biomaterials, revealing good cytocompatibility. The fs-AC had potential prospect for the reconstitution of carious lesion of dental enamel.

  15. (U-Th)/He thermochronology of apatite and its application in Landform revolution

    International Nuclear Information System (INIS)

    The basic principle of apatite (U-Th)/He thermochronomety, dating method, model for correcting He age, closure temperature and the empirical studies, were described in this paper. Its applications in studies of paleo-geomorphology, exhumation history of orogens, and erosion rate were also described. (authors)

  16. Preparation of fluoride substituted apatite cements as the building blocks for tooth enamel restoration

    International Nuclear Information System (INIS)

    Fluoride substituted apatite cement (fs-AC) was synthesized by using the cement powders of tetracalcium phosphate (TTCP) and sodium fluoride (NaF), and the cement powders were mixed with diluted phosphoric acid (H3PO4) as cement liquid to form fs-AC paste. The fs-AC paste could be directly filled into the carious cavities to repair damaged dental enamel. The results indicated that the fs-AC paste was changed into fluorapatite crystals with the atom molar ratio for calcium to phosphorus of 1.66 and the F ion amount of 3 wt% after self-hardening for 2 days. The solubility of fs-AC in Tris-HCl solution (pH 6) was slightly lower than hydroxyapatite cement (HAC) that was similar to the apatite in enamel, indicating the fs-AC was much insensitive to the weakly acidic solution than the apatite in enamel. The fs-AC was tightly combined with the enamel surface because of the chemical reaction between the fs-AC and the apatite in enamel after the caries cavities was filled with fs-AC. The extracts of fs-AC caused no cytotoxicity on L929 cells, which satisfied the relevant criterion on dental biomaterials, revealing good cytocompatibility. The fs-AC had potential prospect for the reconstitution of carious lesion of dental enamel.

  17. Cd2+ and Zn2+ sorption on apatite in the presence of EDTA and humic substance

    Directory of Open Access Journals (Sweden)

    Viipsi K.

    2013-04-01

    Full Text Available The sorption of Cd2+ and Zn2+ on hydroxyapatite [HAP- Ca10(PO46(OH2] and fluorapatite [FAP- Ca10( PO46(F2] with different specific surface area and stoichiometry was investigated in batch experiments in the pH range 4 to 11 (25 ◦C; 0.1 M KNO3. The impact of different conditions was concerned: solution pH, the presence of complexing ligands (EDTA and humic substance and competing metal ions, as well as reaction kinetic and equilibrium conditions. To evaluate the reversibility of Cd2+ sorption onto HAP, desorption characteristics in water, Ca, EDTA, and HUM-solutions were determined. Additionally to solution analysis the surface composition of solid phases was analysed by X-Ray Photoelectron Spectroscopy XPS. The information from the chemical analyses was used to design an equilibration model that takes into account dissolution, surface potential, solution and surface complexation, as well as possible phase transformations. It was revealed that apatites effectively sorb Cd2+ and Zn2+ by ion exchange reactions on surface by formation of new surface phases. Using XPS the formation of a Me-enriched HAP surface was found, which was interpreted as the formation of a solid solution with the general formula: Ca8.4-xMex(HPO41.6(PO44.4(OH0.4. In a binary solution (Cd+Zn the competition of metals reduced individual sorbed amount compared with the single component solutions but the total adsorption maximum was approximately constant. The presence of EDTA reduces the metal sorption on apatite due to [CdEDTA]2- and [ZnEDTA]2- complexes and increases apatite solubility due to [CaEDTA]2- complex formation. The dissolved humic substance was bound on apatite in suspensions but the amount of Cd2+ bound was not changed. The results showed that the solution pH and the presence of complexing ligands have a significant effect on heavy metal sorption on apatite and must be considered if apatites are used as remediation agent. The proposed model can be used to predict

  18. Bone-like apatite coating on functionalized poly(etheretherketone) surface via tailored silanization layers technique

    International Nuclear Information System (INIS)

    Poly(etheretherketone) (PEEK) is a rigid semi-crystalline polymer with outstanding mechanical properties, bone-like stiffness and suitable biocompatibility that has attracted much interest as a biomaterial for orthopedic and dental implants. However, the bio-inert surface of PEEK limits its biomedical applications when direct osteointegration between the implants and the host tissue is desired. In this work, –PO4H2, –COOH and –OH groups were introduced on the PEEK surface by further chemical treatments of the vinyl-terminated silanization layers formed on the hydroxylation-pretreated PEEK surface. Both the surface-functionalized and pristine specimens were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and water contact angle measurements. When placed in 1.5 strength simulated body fluid (SBF) solution, apatite was observed to form uniformly on the functionalized PEEK surface and firmly attach to the substrate. The characterized results demonstrated that the coating was constituted by poorly crystallized bone-like apatite and the effect of surface functional groups on coating formation was also discussed in detail. In addition, in vitro biocompatibility of PEEK, in terms of pre-osteoblast cell (MC3T3-E1) attachment, spreading and proliferation, was remarkably enhanced by the bone-like apatite coating. Thus, this study provides a method to enhance the bioactivity of PEEK and expand its applications in orthopedic and dental implants. - Highlights: • –PO4H2, –COOH and –OH groups were successfully introduced onto PEEK surface via tailored silanization layer technique. • Bone-like apatite formed uniformly on surface-functionalized PEEK after immersion in SBF, and tightly adhered to the PEEK. • SEM, EDS, FTIR, XPS and XRD results showed that apatite layer is composed of low-crystalline bone-like apatite. • Bone-like apatite coating remarkably enhanced pre

  19. Bone-like apatite coating on functionalized poly(etheretherketone) surface via tailored silanization layers technique

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Yanyan [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xiong, Chengdong; Zhang, Shenglan [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041 (China); Li, Xiaoyu [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China); Zhang, Lifang, E-mail: zhanglfcioc@163.com [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041 (China)

    2015-10-01

    Poly(etheretherketone) (PEEK) is a rigid semi-crystalline polymer with outstanding mechanical properties, bone-like stiffness and suitable biocompatibility that has attracted much interest as a biomaterial for orthopedic and dental implants. However, the bio-inert surface of PEEK limits its biomedical applications when direct osteointegration between the implants and the host tissue is desired. In this work, –PO{sub 4}H{sub 2}, –COOH and –OH groups were introduced on the PEEK surface by further chemical treatments of the vinyl-terminated silanization layers formed on the hydroxylation-pretreated PEEK surface. Both the surface-functionalized and pristine specimens were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and water contact angle measurements. When placed in 1.5 strength simulated body fluid (SBF) solution, apatite was observed to form uniformly on the functionalized PEEK surface and firmly attach to the substrate. The characterized results demonstrated that the coating was constituted by poorly crystallized bone-like apatite and the effect of surface functional groups on coating formation was also discussed in detail. In addition, in vitro biocompatibility of PEEK, in terms of pre-osteoblast cell (MC3T3-E1) attachment, spreading and proliferation, was remarkably enhanced by the bone-like apatite coating. Thus, this study provides a method to enhance the bioactivity of PEEK and expand its applications in orthopedic and dental implants. - Highlights: • –PO{sub 4}H{sub 2}, –COOH and –OH groups were successfully introduced onto PEEK surface via tailored silanization layer technique. • Bone-like apatite formed uniformly on surface-functionalized PEEK after immersion in SBF, and tightly adhered to the PEEK. • SEM, EDS, FTIR, XPS and XRD results showed that apatite layer is composed of low-crystalline bone-like apatite. • Bone-like apatite coating

  20. Carbonate-containing apatite (CAP) synthesis under moderate conditions starting from calcium carbonate and orthophosphoric acid

    International Nuclear Information System (INIS)

    The synthesis of carbonate-containing apatite (CAP) from calcium carbonate and orthophosphoric acid under moderate conditions was investigated. In all cases, complete precipitation of orthophosphate species was observed. The reaction temperature influenced strongly the decomposition of calcium carbonate and therefore the composition of formed products. The reaction temperature of 80 °C was found to be effective for the complete decomposition of calcium carbonate particles after 48 h of reaction. Infra-red spectroscopy (IR), nuclear magnetic resonance (NMR), thermogravimetry/mass spectroscopy (TG–MS) coupling, and X-ray diffraction (XRD) characterizations allowed the identification of the composition of formed products. By increasing the reaction temperature from 20 °C to 80 °C, the content of A-type CAP increased and that of B-type CAP decreased, according to the favorable effect of temperature on the formation of A-type CAP. The total amount of carbonate content incorporated in CAP's structure, which was determined by TG–MS analysis, increased with the reaction temperature and reached up to 4.1% at 80 °C. At this temperature, the solid product was mainly composed of apatitic components and showed the typical flat-needle-like structure of CAP particles obtained in hydrothermal conditions. These results show an interesting one-step synthesis of CAP from calcium carbonate and orthophosphoric acid as low cost but high purity starting materials. Highlights: • The synthesis of carbonate-containing apatites from CaCO3 and H3PO4 was studied. • The decomposition of CaCO3 particles was complete at 80 °C, 13.2 bar for 48 h. • The transformation of CaCO3 and H3PO4 into apatitic products was also complete. • Pure carbonate-containing apatite was directly obtained without water-rising step

  1. Xe- and U-tracks in apatite and muscovite near the etching threshold

    Energy Technology Data Exchange (ETDEWEB)

    Wauschkuhn, Bastian, E-mail: wauschku@geo.tu-freiberg.de [Geologie, Technische Universität Bergakademie Freiberg (Germany); Jonckheere, Raymond [Geologie, Technische Universität Bergakademie Freiberg (Germany); Mineralogie en Petrologie, Geologie en Bodemkunde, Universiteit Gent (Belgium); Ratschbacher, Lothar [Geologie, Technische Universität Bergakademie Freiberg (Germany)

    2015-01-15

    Ion irradiation of a wedge-shaped Durango apatite backed by a mica detector allows investigating ion track ranges and etching properties at different points along the tracks. Transmission profiles obtained by irradiation with 2 × 10{sup 6} cm{sup −2} 11.1 MeV/amu {sup 132}Xe and 2 × 10{sup 6} cm{sup −2} 11.1 MeV/amu {sup 238}U parallel to the apatite c-axis correspond to ranges calculated with SRIM (Xe: 76.3 μm; U: 81.1 μm). However, the measured profiles show much greater etchable track-length variations than the calculated longitudinal straggles. The probable cause is that the length deficit exhibits significant variation from track to track. The measured length deficit in muscovite is in agreement with most existing data. In contrast, the length deficit in apatite appears to be close to zero, which is in conflict with all earlier estimates. This probably results from the etching properties of the apatite basal face, which permit surface-assisted sub-threshold etching of track sections in the nuclear stopping regime. These sections are not accessible from the opposite direction, i.e. by etching towards the endpoint of the tracks or in the direction of the ion beam. This conclusion is supported by the fact that linear dislocations are revealed in apatite basal faces and by the observation of imperfect etch pits that are separated from the etched ion track channel by a section that appears unetched under the microscope.

  2. Thermal annealing of fission tracks in fluorapatite, chlorapatite, manganoanapatite, and Durango apatite: experimental results

    International Nuclear Information System (INIS)

    It is well known that the optically measured lengths of fission tracks in apatite crystals are a function of etching conditions, crystallographic orientation of the track, composition of the crystal, and the state of thermal annealing. In this study we standardize etching conditions and optimize track length measurability by etching until etch pits formed at the surface of each apatite crystal reached widths of about 0.74 μm. Etching times using 5M HNO3 at 21oC were 31 s for Otter Lake, Quebec, fluorapatite; 47 s for Durango, Mexico, apatite; 33 s for Portland, Connecticut, manganoanapatite; and 11 s for Bamle, Norway, chlorapatite. An etching experiment using two etchant strengths (5M and 1.6M HNO3) revealed that, despite significant differences in etch pit shape, fission-track length anisotropy with respect to crystallographic orientation of the tracks is not a chemical etching effect. A series of 227 constant-temperature annealing experiments were carried out on nuclear reactor induced tracks in oriented slices of the apatites. After etching, crystallographic orientations of tracks were measured along with their lengths. The 200-300 track lengths measured for each slice were ellipse-fitted to give the major (c crystallographic direction) and minor (a crystallographic direction) semi-axes used to calculate equivalent isotropic lengths. The equivalent isotropic length is more useful than mean length for thermal history analysis because the variation caused by anisotropy has been removed. Using normalized etching procedures and equivalent isotropic length data, we found that the fluorapatite anneals most readily, followed by Durango apatite, manganoanapatite, and lastly chlorapatite. (author)

  3. Absolute dating of the youngest sediments of the Swiss Molasse basin by apatite fission track analysis

    International Nuclear Information System (INIS)

    A set of ash layer samples within the uppermost Upper Freshwater Molasse (OSM) sediments (N and E of Frauenfeld, Switzerland) was dated by apatite fission track (FT) means. The ages indicate an early Tortonian (perhaps latest Serravallian) eruption and sedimentation age of 11.5 ± 0.3 Ma. The age is in agreement with time constraints by Mammalian relicts which point to MN7-8. Due to the position of the ash layers close to the erosional gap and overlying Quaternary cover, the age represents a maximum age for the cessation of OSM sedimentation in the Swiss Molasse Basin. However, the end of Molasse sedimentation in this region had not stopped before the cover of OSM sediments by volcanic ash layers at the Hoewenegg volcano (southern Germany), an event further constrained by an apatite FT age of 9.8 (-0.7/+0.8) Ma from a hornblende-bearing ash layer at Hoewenegg. An isolated bentonitic ash layer occurring 25 km to the WSW of the main set of dated ashes (near Humlikon) has an age component identical to the OSM ash layers near Frauenfeld. The age suggests a source for this material within the Hegau, but is too young to be related to the volcanic activity at the Kaiserstuhl. The apatites from the ash layer samples show two distinct compositional populations, one very close to a Cl end member and one with apatites of equal proportions of Cl and OH end member. These populations are interpreted to have possibly originated from at least two distinct igneous sources for the ashes, separated by their eruption site or eruption time or both. The distinct compositional data on the volcanic apatites may provide a basis to clarify their origin in future work. (author)

  4. A taxonomy of apatite frameworks for the crystal chemical design of fuel cell electrolytes

    International Nuclear Information System (INIS)

    Apatite framework taxonomy succinctly rationalises the crystallographic modifications of this structural family as a function of chemical composition. Taking the neutral apatite [La8Sr2][(GeO4)6]O2 as a prototype electrolyte, this classification scheme correctly predicted that 'excess' oxygen in La9SrGe6O26.5 is tenanted in the framework as [La9Sr][(GeO4)5.5(GeO5)0.5]O2, rather than the presumptive tunnel location of [La9Sr][(GeO4)6]O2.5. The implication of this approach is that in addition to the three known apatite genera-A10(BO3)6X2, A10(BO4)6X2, A10(BO5)6X2-hybrid electrolytes of the types A10(BO3/BO4/BO5)6X2 can be designed, with potentially superior low-temperature ion conduction, mediated by the introduction of oxygen to the framework reservoir. - Graphical abstract: Apatite framework taxonomy succinctly rationalises the crystallographic modifications of this structural family as a function of chemical composition. Neutron diffraction identified that the excess oxygen in La9SrGe6O26.5 is tenanted in the framework as [La9Sr][(GeO4)5.5(GeO5)0.5]O2. The implication of this approach is that in addition to the three known apatite genera-A10(BO3)6X2, A10(BO4)6X2, A10(BO5)6X2-hybrid electrolytes of the types A10(BO3/BO4/BO5)6X2 can be designed

  5. Apatite-forming ability of vinylphosphonic acid-based copolymer in simulated body fluid: effects of phosphate group content.

    Science.gov (United States)

    Hamai, Ryo; Shirosaki, Yuki; Miyazaki, Toshiki

    2016-10-01

    Phosphate groups on materials surfaces are known to contribute to apatite formation upon exposure of the materials in simulated body fluid and improved affinity of the materials for osteoblast-like cells. Typically, polymers containing phosphate groups are organic matrices consisting of apatite-polymer composites prepared by biomimetic process using simulated body fluid. Ca(2+) incorporation into the polymer accelerates apatite formation in simulated body fluid owing because of increase in the supersaturation degree, with respect to apatite in simulated body fluid, owing to Ca(2+) release from the polymer. However, the effects of phosphate content on the Ca(2+) release and apatite-forming abilities of copolymers in simulated body fluid are rather elusive. In this study, a phosphate-containing copolymer prepared from vinylphosphonic acid, 2-hydroxyethyl methacrylate, and triethylene glycol dimethacrylate was examined. The release of Ca(2+) in Tris-NaCl buffer and simulated body fluid increased as the additive amount of vinylphosphonic acid increased. However, apatite formation was suppressed as the phosphate groups content increased despite the enhanced release of Ca(2+) from the polymer. This phenomenon was reflected by changes in the surface zeta potential. Thus, it was concluded that the apatite-forming ability of vinylphosphonic acid-2-hydroxyethyl methacrylate-triethylene glycol dimethacrylate copolymer treated with CaCl2 solution was governed by surface state rather than Ca(2+) release in simulated body fluid. PMID:27585911

  6. Hydrogen and carbon abundances and isotopic ratios in apatite from alkaline intrusive complexes, with a focus on carbonatites

    Energy Technology Data Exchange (ETDEWEB)

    Nadeau, S.L.; Epstein, S.; Stolper, E. [California Inst. of Tech., Pasadena, CA (United States). Div. of Geological and Planetary Sciences

    1999-06-01

    The authors report H and C contents and {delta}D and {delta}{sup 13}C values of apatites from 15 alkaline intrusive complexes ranging in age from 110 Ma to 2.6 Ga. Sampling focused on carbonatites, but included silicate rocks as well. Heating temperatures up to 1,500 C is needed to extract fully H{sub 2}O and CO{sub 2} from these apatites. Apatites from carbonatite-rich intrusive complexes contain 0.2--1.1 wt% H{sub 2}O and 0.05--0.70 wt% CO{sub 2}; apatites from two silicate-rich alkaline complexes with little or no carbonatite are generally poorer in both volatile components (0.1--0.2% H{sub 2}O and 0.01--0.11% CO{sub 2}). D/H ratios in apatites from these rocks are bimodally distributed. The authors suggest that the {delta}D values of group I apatites represent primitive, mantle-derived values and that the group II apatites crystallized from degassed magmas, resulting in lower H{sub 2}O contents and {delta}D values. In contrast to H{sub 2}O contents and {delta}D values, CO{sub 2} contents and {delta}{sup 13}C values of gas released at high temperatures from multiple aliquots of these apatite samples are variable. This suggests the presence of more than one C-bearing component in these apatites, one of which is proposed to be dissolved carbonate; the other could be associated with hydrocarbons.

  7. Postmagmatic magnetite-apatite assemblage in mafic intrusions: a case study of dolerite at Olympic Dam, South Australia

    Science.gov (United States)

    Apukhtina, Olga B.; Kamenetsky, Vadim S.; Ehrig, Kathy; Kamenetsky, Maya B.; McPhie, Jocelyn; Maas, Roland; Meffre, Sebastien; Goemann, Karsten; Rodemann, Thomas; Cook, Nigel J.; Ciobanu, Cristiana L.

    2016-01-01

    An assemblage of magnetite and apatite is common worldwide in different ore deposit types, including disparate members of the iron-oxide copper-gold (IOCG) clan. The Kiruna-type iron oxide-apatite deposits, a subtype of the IOCG family, are recognized as economic targets as well. A wide range of competing genetic models exists for magnetite-apatite deposits, including magmatic, magmatic-hydrothermal, hydrothermal(-metasomatic), and sedimentary(-exhalative). The sources and mechanisms of transport and deposition of Fe and P remain highly debatable. This study reports petrographic and geochemical features of the magnetite-apatite-rich vein assemblages in the dolerite dykes of the Gairdner Dyke Swarm (~0.82 Ga) that intruded the Roxby Downs Granite (~0.59 Ga), the host of the supergiant Olympic Dam IOCG deposit. These symmetrical, only few mm narrow veins are prevalent in such dykes and comprise besides usually colloform magnetite and prismatic apatite also further minerals (e.g., calcite, quartz). The genetic relationships between the veins and host dolerite are implied based on alteration in the immediate vicinity (~4 mm) of the veins. In particular, Ti-magnetite-ilmenite is partially to completely transformed to titanite and magmatic apatite disappears. We conclude that the mafic dykes were a local source of Fe and P re-concentrated in the magnetite-apatite veins. Uranium-Pb ages for vein apatite and titanite associated with the vein in this case study suggest that alteration of the dolerite and healing of the fractures occurred shortly after dyke emplacement. We propose that in this particular case the origin of the magnetite-apatite assemblage is clearly related to hydrothermal alteration of the host mafic magmatic rocks.

  8. Reduction And Stabilization (Immobilization) Of Pertechnetate To An Immobile Reduced Technetium Species Using Tin(II) Apatite

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, J. B.

    2012-11-02

    Synthetic tin(II)apatite reduces pertechnetate from the mobile +7 to a non-mobile oxidation state and sequesters the technetium, preventing re-oxidization to mobile +7 state under acidic or oxygenated conditions. Previous work indicated technetium reacted Sn(II)apatite can achieve an ANSI leachability index of 12.8 in Cast Stone. An effect by pH is observed on the distribution coefficient, the highest distribution coefficient being l70,900 observed at pH levels of 2.5 to 10.2. The tin apatite was resistant to releasing technetium under test conditions.

  9. Reduction And Stabilization (Immobilization) Of Pertechnetate To An Immobile Reduced Technetium Species Using Tin(II) Apatite

    International Nuclear Information System (INIS)

    Synthetic tin(II)apatite reduces pertechnetate from the mobile +7 to a non-mobile oxidation state and sequesters the technetium, preventing re-oxidization to mobile +7 state under acidic or oxygenated conditions. Previous work indicated technetium reacted Sn(II)apatite can achieve an ANSI leachability index of 12.8 in Cast Stone. An effect by pH is observed on the distribution coefficient, the highest distribution coefficient being l70,900 observed at pH levels of 2.5 to 10.2. The tin apatite was resistant to releasing technetium under test conditions

  10. The study of geochemical behavior of rare earth elements in apatites from the Hormoz Island, Persian Gulf

    OpenAIRE

    Ali Rostami; Marziyeh Bazamad; Behzad Hajalilou; Mohssen Moazzen

    2014-01-01

    The study area is located about 3 km southwest of the Hormoz Island in the Hormozgan province, in the Persian Gulf. The main rock units in the region consist of a highly altered acidic pluton cratophyre, which is responsible for apatite formation, diabasic dike, marl and altered basalt. Apatite is the only phosphate mineral in the Hormoz Island, which has accumulated REE in its crystal structure. The amount of Na2O and SiO2 oxides in apatite are high and the average content of the main ele...

  11. Biogenic hydroxyapatite (Apatite II™) dissolution kinetics and metal removal from acid mine drainage

    International Nuclear Information System (INIS)

    Apatite II™ is a biogenic hydroxyapatite (expressed as Ca5(PO4)OH) derived from fish bone. Using grains of Apatite II™ with a fraction size between 250 and 500 μm, batch and flow-through experiments were carried out to (1) determine the solubility constant for the dissolution reaction Ca5(PO4)3(OH) ⇔ 5Ca2+ + 3PO43− + OH−, (2) obtain steady-state dissolution rates over the pH range between 2.22 and 7.14, and (3) study the Apatite II™’s mechanisms to remove Pb2+, Zn2+, Mn2+, and Cu2+ from metal polluted water as it dissolves. The log KS value obtained was −50.8 ± 0.82 at 25 °C. Far-from-equilibrium fish-bone hydroxyapatite dissolution rates decrease by increasing pH. Assuming that the dissolution reaction is controlled by fast adsorption of a proton on a specific surface site that dominates through the pH range studied, probably ≡P-O−, followed by a slow hydrolysis step, the dissolution rate dependence is expressed in mol m−2 s−1 as Rate25°C=−8.9×10−10×(9.96×105×aH+)/(1+9.96×105×aH+) where aH+ is the proton activity in solution. Removal of Pb2+, Zn2+, Mn2+ and Cu2+ was by formation of phosphate-metal compounds on the Apatite II™ substrate, whereas removal of Cd2+ was by surface adsorption. Increase in pH enhanced the removal of aqueous heavy metals. Using the kinetic parameters obtained (e.g., dissolution rate and pH-rate dependence law), reactive transport simulations reproduced the experimental variation of pH and concentrations of Ca, P and toxic divalent metal in a column experiment filled with Apatite II™ that was designed to simulate the Apatite II™–metal polluted water interaction.

  12. The Effect of Nano-apatite on the Expression of Telomerase Gene of Human Hepatocellular Carcinoma Cells

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    To investigate the effect of nano- apatite on the expression of the telomerase gene of human hepatocellular carcinoma cell lines and further explore the mechanism of the nano-apatite inhibiting cancer cells. Using the hybridization in situ method to detect the expression of the telomerase gene of human hepatocellular carcinoma cells treated with the nano- apatite for 4 h at 37 ℃. The hybridization in situ showed that the cytoplasm of the positive cells was stained in nigger-brown. The positive cell rate of the control group was 88.49% , the cisplatin group was 25.6% , the nano-apatite group was 63.6% . The activity oftelomerase gene was both obviously declined comparing with the control group and the difference had significance (p < 0.05, p < 0.01 ). The nanoapatite obviously inhabit the expression of the telomerase gene of human hepatocellular carcinoma cells.

  13. LABORATORY REPORT ON THE REDUCTION AND STABILIZATION (IMMOBILIZATION) OF PERTECHNETATE TO TECHNETIUM DIOXIDE USING TIN(II)APATITE

    Energy Technology Data Exchange (ETDEWEB)

    DUNCAN JB; HAGERTY K; MOORE WP; RHODES RN; JOHNSON JM; MOORE RC

    2012-06-01

    This effort is part of the technetium management initiative and provides data for the handling and disposition of technetium. To that end, the objective of this effort was to challenge tin(II)apatite (Sn(II)apatite) against double-shell tank 241-AN-105 simulant spiked with pertechnetate (TcO{sub 4}{sup -}). The Sn(II)apatite used in this effort was synthesized on site using a recipe developed at and provided by Sandia National Laboratories; the synthesis provides a high quality product while requiring minimal laboratory effort. The Sn(II)apatite reduces pertechnetate from the mobile +7 oxidation state to the non-mobile +4 oxidation state. It also sequesters the technetium and does not allow for re-oxidization to the mo bile +7 state under acidic or oxygenated conditions within the tested period oftime (6 weeks). Previous work (RPP-RPT-39195, Assessment of Technetium Leachability in Cement-Stabilized Basin 43 Groundwater Brine) indicated that the Sn(II)apatite can achieve an ANSI leachability index in Cast Stone of 12.8. The technetium distribution coefficient for Sn(II)apatite exhibits a direct correlation with the pH of the contaminated media. Table A shows Sn(II)apatite distribution coefficients as a function of pH. The asterisked numbers indicate that the lower detection limit of the analytical instrument was used to calculate the distribution coefficient as the concentration of technetium left in solution was less than the detection limit. The loaded sample (200 mg of Sn(II)apatite loaded with O.311 mg of Tc-99) was subjected to different molarities of nitric acid to determine if the Sn(II)apatite would release the sequestered technetium. The acid was allowed to contact for 1 minute with gentle shaking ('1st wash'); the aqueous solution was then filtered, and the filtrate was analyzed for Tc-99. Table B shows the results ofthe nitric acid exposure. Another portion of acid was added, shaken for a minute, and filtered ('2nd wash'). The

  14. The influence of unstable signals for electron spin resonance dosimetry with synthetic A-type carbonated apatite

    International Nuclear Information System (INIS)

    Synthetic A-type carbonated apatite prepared in reproducible conditions was irradiated at room temperature with 60Co gamma rays. The ESR spectrum is associated to axial CO2- and orthorhombic CO3- species. Radicals used as dose markers in biological apatites are long-lived paramagnetic species. The stability of the post-irradiation signal of A-type apatite was investigated for more than one year. Measurements showed variations in the spectra attributed to unstable CO3- species, which can be eliminated by thermal treatments at 100 deg. C for 24 h. The CO2-spectrum can be identified in samples irradiated up to 0.2 Gy. All results indicate that the A-type apatite is an appropriate materials for radiotherapy dosimetry. (author)

  15. Meso-Cenozoic tectonics of the Central Kyrgyz Tien Shan (Central Asia), based on apatite fission track thermochronology.

    OpenAIRE

    Glorie, Stijn

    2008-01-01

    Apatite fission track thermochronology on the Kyrgyz Tien Shan basement revealed a polyphased thermal history of the study-area. We interpret the Mesozoic and Cenozoic cooling-events as periods of tectonic reactivation.

  16. Morphological and chemical characterisation of biomimetic bone like apatite formation on alkali treated Ti6Al4V titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Faure, J. [INSERM-ERM 0203, Laboratoire de Microscopie Electronique, 21, rue Clement Ader, 51685 Reims, Cedex 02 (France); Balamurugan, A., E-mail: abmurugan@yahoo.co.in [INSERM-ERM 0203, Laboratoire de Microscopie Electronique, 21, rue Clement Ader, 51685 Reims, Cedex 02 (France); Department of Ceramics and Glass Engineering, University of Aveiro, CICECO, 3810-193 Aveiro (Portugal); Benhayoune, H. [INSERM-ERM 0203, Laboratoire de Microscopie Electronique, 21, rue Clement Ader, 51685 Reims, Cedex 02 (France); Torres, P. [Department of Ceramics and Glass Engineering, University of Aveiro, CICECO, 3810-193 Aveiro (Portugal); Balossier, G. [INSERM-ERM 0203, Laboratoire de Microscopie Electronique, 21, rue Clement Ader, 51685 Reims, Cedex 02 (France); Ferreira, J.M.F. [Department of Ceramics and Glass Engineering, University of Aveiro, CICECO, 3810-193 Aveiro (Portugal)

    2009-05-05

    The present study is an attempt to enhance the apatite-forming ability of titanium metal induced by the alkaline (NaOH) treatment. A cell free culture medium, acellular DMEM solution was utilised to develop bone-like apatite on alkali-treated titanium alloy surface. The main advantage of this process is the development of bone like apatite with essential trace elements on the metallic substrate by using the DMEM culture medium as a soaking medium. The formed apatite deposits were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDXS). The obtained results suggest that the method utilized in this work can be successfully applied to obtain deposition of uniform coatings of crystalline hydroxyapatite on alkali treated titanium substrates.

  17. Morphological and chemical characterisation of biomimetic bone like apatite formation on alkali treated Ti6Al4V titanium alloy

    International Nuclear Information System (INIS)

    The present study is an attempt to enhance the apatite-forming ability of titanium metal induced by the alkaline (NaOH) treatment. A cell free culture medium, acellular DMEM solution was utilised to develop bone-like apatite on alkali-treated titanium alloy surface. The main advantage of this process is the development of bone like apatite with essential trace elements on the metallic substrate by using the DMEM culture medium as a soaking medium. The formed apatite deposits were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDXS). The obtained results suggest that the method utilized in this work can be successfully applied to obtain deposition of uniform coatings of crystalline hydroxyapatite on alkali treated titanium substrates.

  18. BMP-2 and ALP gene expression induced by a BMP-2 gene-fibronectin-apatite composite layer

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xiupeng; Sogo, Yu; Li Xia; Ito, Atsuo [Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566 (Japan); Oyane, Ayako [Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan); Tsurushima, Hideo, E-mail: xp-wang@aist.go.jp, E-mail: xiupengw@hotmail.com [Department of Neurosurgery, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8575 (Japan)

    2011-08-15

    The bone morphogenetic protein 2 (BMP-2) gene delivery system with a gene-fibronectin (Fn)-apatite composite layer was fabricated on the surface of a hydroxyapatite ceramic scaffold. The BMP-2 gene-Fn-apatite composite layer was coated on the scaffold using a supersaturated calcium phosphate solution supplemented with BMP-2 DNA and Fn. The scaffolds were ectopically implanted into the dorsal subcutaneous tissue of rats. Four weeks after the implantation, the hydroxyapatite scaffold coated with the BMP-2 gene-Fn-apatite composite layer showed improved gene expressions of BMP-2 and alkaline phosphatase as compared with the scaffold coated with the apatite layer. Although these results suggest the possibility of ectopic bone formation induced by the present gene delivery system, further study is necessary to prove this.

  19. A comprehensive guide to experimental and predicted thermodynamic properties of phosphate apatite minerals in view of applicative purposes

    International Nuclear Information System (INIS)

    Graphical abstract: Experimental thermodynamic properties of phosphate apatites are reviewed and commented. Predictive methods are developed and tested here for apatite compounds, allowing reliable estimations of ΔHf°, ΔGf° and S°, not only for end-members but also for solid solutions, non-stoichiometric and hydrated samples. A periodic table of recommended thermodynamic properties for 33 apatite systems is generated, and relative stabilities are pointed out. - Highlights: • Experimental thermodynamic properties of phosphate apatites are reviewed. • Predictive thermodynamic methods are investigated for estimating missing data. • An additive model is developed to estimate ΔHf°, ΔGf° and S° for phosphate apatites. • End-members, solid solutions, nonstoichiometric and hydrated samples are considered. • A periodic table of recommended thermodynamic properties for 33 systems is proposed. - Abstract: Apatite minerals represent a major class of ionic compounds of interest to many disciplines including medical sciences, geology, anthropology, cosmology, environmental and nuclear sciences. Yet, these compounds have not received great attention from a thermodynamic viewpoint, and some diverging data – often drawn from molecular modeling assays – were reported. In this contribution, an extensive literature overview of available experimental-based data on M10(PO4)6X2 apatites with M = Ca, Ba, Sr, Mg, Cd, Pb, Cu, Zn and X = OH, F, Cl or Br has first been made, on the basis of standard formation energetics (ΔHf° and ΔGf°) as well as entropy S° and molar heat capacity Cp,m°. The case of oxyapatite was also included. From this overview, it was then possible to identify general tendencies, evidencing in particular the primary role of electronegativity and secondarily of ionic size. Using the experimental data as reference, several predictive thermodynamic methods were then evaluated, including the volume-based-thermodynamics (VBT) method and a more

  20. Phosphorus removal by apatite in horizontal flow constructed wetlands for small communities: pilot and full-scale evidence

    OpenAIRE

    Harouiya, N.; Martin Ruel, S.; Prost-Boucle, S.; Liénard, A.; Esser, D.; Molle, P.

    2011-01-01

    Phosphorus (P) removals in constructed wetlands (CWs) have received particular attention in recent decades by using specific materials which promote adsorption/precipitation mechanisms. Recent studies have shown interest in using apatite materials to promote P precipitation onto the particle surface. As previous trials were mainly done by lab experiments, this present study aims to evaluate the real potential of apatites to remove P from wastewater in pilot units and a full-scale plant over a...

  1. Osteoclastic resorption of bone-like apatite formed on a plastic disk as an in vitro assay system.

    Science.gov (United States)

    Matsuoka, H; Nakamura, T; Takadama, H; Yamada, S; Tamura, J; Okada, Y; Oka, M; Kokubo, T

    1998-11-01

    We have investigated the applicability of a simple and inexpensive osteoclastic assay system using bone-like apatite-coated polyethyleneterephthalate (PET) disks. A 1 microm thick apatite layer, uniform and homogeneous bone-mineral-like with no organic components, was made on PET disks using a biomimetic process. As substrates for an osteoclastic assay, these coated disks were compared with dentine as well as with bone-like or heat-treated apatite of various thicknesses on apatite- and wollastonite-containing glass ceramic (A-W GC) disks. The unfractionated bone cells, including osteoclasts, of a neonatal rabbit were seeded onto these substrates. By scanning electron microscopic examination, the resorption lacunae of the thick bone-like apatite clearly showed track-like shapes at various depths, similar to those of dentine although the border between the A-W GC and the apatite was unclear. In contrast, those of heat-treated apatite showed small and shallow shapes with irregular margins, quite different from those of dentine. By reducing the thickness of bone-like apatite to 1 microm as well as using PET as its substrate, the margins of the resorption lacunae became quite clear, and with the use of phase-contrast microscopy during culture, osteoclasts and resorption pits could be precisely observed. The resorbed area, easily measured with the aid of bright-field microscopy and an image analyzer, was found to have increased in a time-dependent manner and at the end of 4 days of culture was not statistically different from that of dentine. PMID:9773824

  2. PIXE analysis of apatite from granitic pegmatite dikes near cross lake

    International Nuclear Information System (INIS)

    The study of the elements in 31 accessory apatites in pegmatite field illustrates the usefulness of PIXE in the measurement of elements in rocks and minerals. Based on the elemental composition results, the behavior of REE and other trace elements within the pegmatite system is discussed, the concentration distribution of the substitution elements in apatite to their locations in the field and to the geochemical characteristics of the K-feldspars. The average cK/cRb value for the core margin K-feldspars is considered as a reliable indicator of the general level of the fractionation by the pegmatite. Consequently the element concentration distribution trend due to fractionation may be illustrated by a plot of it against the cK/cRb ratio

  3. In vivo apatite formation induced on titanium metal and its alloys by chemical treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kokubo, T.; Kim, H.M. [Kyoto Univ. (Japan). Dept. of Material Chemistry; Nishiguchi, S.; Nakamura, T. [Kyoto Univ. (Japan). Dept. of Orthopaedic Surgery

    2001-07-01

    NaOH and heat treatments form an amorphous sodium titanate layer with a graded structure on the surfaces of titanium metal and its alloys. These treatments give no adverse effect on mechanical properties of the metals. Thus treated metals form an apatite layer on their surfaces in the living body by taking the calcium and phosphate ions from the surrounding fluid. This apatite layer is tightly integrated to the metal substrates through a graded structure, and bonds to the living bone in a short period, because of its structure and composition analogous to those of the bone mineral. This kind of bioactive metals are believed to be useful as bone substitutes even under load bearing conditions such as hip joints and dental implants. (orig.)

  4. Phosphate-induced metal stabilization: Use of apatite and bone char for the removal of soluble radionuclides in authentic and simulated DOE groundwater

    International Nuclear Information System (INIS)

    The apatite group of minerals is a family of calcium phosphate phases. Apatite is the principal component of bone tissue, and it also occurs naturally as mineral deposits in the geosphere. Bone char is calcined (coked) animal bone, containing activated carbon as well as calcium phosphate mineral phases. Apatite IItrademark is a more reactive form of apatite, supplied by UFA Ventures, Inc., at a cost of approximately 1/4 that of commercial bone char. Apatite is shown to be effective for the removal of select heavy metal impurities in groundwater. Previous investigations have demonstrated that apatite is an effective medium for the stabilization of soluble lead, cadmium, and zinc from mine waste leachate by the formation of highly insoluble precipitate phases. The performance of bone char and apatite II are compared with other candidate sorption media (including granular activated carbon and anion exchange resin) for the removal of soluble uranyl ion in synthetic DOE Site groundwater supplemented with varying levels of interfering nitrate ion. Apatite II has a greater affinity for U(VI), especially in the presence of nitrate ion, as evidenced by a larger value for the conditional distribution coefficient (Kd) in batch test experiments. Contact of uranyl nitrate solution with apatite II is shown to produce highly insoluble mineral phases of the autunite group (calcium uranyl phosphate hydrates). Apatite II is also demonstrated to be moderately effective for the removal of soluble radioactive isotopes of strontium, but not cesium, when these ions are supplemented into authentic DOE Site groundwater

  5. Apatite fission track study of Taibai Mountain uplift in the mesozoic-cenozoic

    International Nuclear Information System (INIS)

    The apatite fission track results of 14 samples from Taibai Mountain suggest that Taibai Mountain underwent two episodic uplifts. These two uplifts occurred at about 100-80 Ma and 40 Ma, respectively. These are consistent with the conclusion that Qinling Mountain changed to a new tectonic evolution phase since about late Cretaceous, and this evolution resulted in the basic tectonic geomorphologic pattern of Qinling Mountain. (authors)

  6. Enhanced apatite formation on Ti metal heated in PO2-controlled nitrogen atmosphere.

    Science.gov (United States)

    Hashimoto, Masami; Hayashi, Kazumi; Kitaoka, Satoshi

    2013-10-01

    The oxynitridation of biomedical titanium metal under a precisely regulated oxygen partial pressure (PO2) of 10(-14)Pa in nitrogen atmosphere at 973 K for 1 h strongly enhanced apatite formation compared with that on Ti heated in air. The factors governing the high apatite-forming ability are discussed from the viewpoint of the surface properties of Ti heated under a PO2 of 10(-14)Pa in nitrogen atmosphere determined from X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and zeta potential measurements. Nitrogen (N)-doped TiO2 (interstitial N) was formed on pure Ti heated under a PO2 of 10(-14)Pa in nitrogen atmosphere at 973 K. The XPS O1s main peak shifted toward a lower binding energy upon heating under a PO2 of 10(-14)Pa. This shift may be due to the formation of oxygen vacancies. This Ti surface had a positive zeta potential of approximately 20 mV. According to time-of-flight secondary ion mass spectroscopy results, PO4(3-) ions were predominantly adsorbed on Ti soaked in simulated body fluid (SBF) after heat treatment, followed by calcium ions. It was concluded that the apatite formation kinetics can be described using the Avrami-Erofeev equation with an Avrami index of n=2, which implies the instantaneous nucleation of apatite on the surface of Ti soaked in SBF after heat treatment at 973 K under a PO2 of 10(-14)Pa. PMID:23910327

  7. Zircon and apatite fission-track dating of the James Ross Basin sediments (Antarctic Peninsula)

    Czech Academy of Sciences Publication Activity Database

    Svojtka, Martin; Nývlt, D.; Murakami, M.; Macáková, J.; Filip, Jiří; Mixa, P.

    Teplá: Czech Geological Survey, 2007. s. 84-84. [CzechTec 07. Meeting of the Central European Tectonic Studies Group (CETeG) /5./ and Meeting of the Czech Tectonic Studies Group (ČTS) /12./. 11.04.2007-14.04.2007, Teplá] R&D Projects: GA MŠk 1K05030 Institutional research plan: CEZ:AV0Z30130516 Keywords : zircon * apatite * James Ross Island Subject RIV: DB - Geology ; Mineralogy

  8. Effects of Fluoride on the Interactions between Amelogenin and Apatite Crystals

    OpenAIRE

    Tanimoto, K; Le, T; Zhu, L; Chen, J.; Featherstone, JDB; Li, W; Denbesten, P

    2008-01-01

    Fluorosed enamel is more porous and less mineralized, possibly related to altered amelogenin-modulated crystal growth. The purpose of this study was to examine the role of fluoride in interactions between amelogenin and apatite crystals. Recombinant human amelogenin (rhl74) was bound to carbonated hydroxyapatite containing various amounts of fluoride, and analyzed by protein assay, SDS PAGE, and AFM. Interactions between rh174 and fluoride were assayed by isothermal titration calorimetry (ITC...

  9. Novel bioactive Fe-based metallic glasses with excellent apatite-forming ability.

    Science.gov (United States)

    Qin, Chunling; Hu, Qingfeng; Li, Yongyan; Wang, Zhifeng; Zhao, Weimin; Louzguine-Luzgin, Dmitri V; Inoue, Akihisa

    2016-12-01

    We demonstrate, for the first time, that the (Fe0.75B0.15Si0.1)100-xNbx (x=0, 1 and 3at.%) metallic glasses without toxic and allergic elements exhibit excellent apatite-forming ability in simulated body fluids (SBF), which is expected to be a new generation of biomaterials in stents and orthopedic implants. For the alloys without any surface treatment, spherical particles corresponding to octacalcium phosphate are spontaneously nucleated and precipitated throughout the alloy surface after immersion only for 1day, indicating that the present alloys possess an unusual high bioactivity. During the subsequent in-vitro immersion for 3days, SEM image reveals the typical 'cauliflower' morphology of bone-like hydroxyapatite (HA) with Ca/P ratio of 1.65. In addition, it is surprising to find that the in-vitro SBF immersion not only leads to the formation and growth of the apatite layer but also causes the progressive development of the underlying alloy substrate. Moreover, for the alloys immersed for 3 or 9days, the substrate alloy just beneath the apatite layer consists of a hierarchical nano/macro-porous structure through selective dissolution of the active components Fe and B in the surface. XPS analysis indicates that the apatite nucleation on the present alloys in SBF is attributed to the specific dissolution properties of the present alloys and the fast formation of Si-OH and Fe-OH or Nb-OH functional groups, followed by combination of these groups with Ca(2+) and phosphate ions. PMID:27612742

  10. Phosphorus removal by the use of apatite in constructed wetlands: design recommendations

    OpenAIRE

    Molle, P.; Martin, S.; Esser, D.; Besnault, S.; Morlay, C.; Harouiya, N.

    2011-01-01

    Phosphorus (P) removal in constructed wetlands (CWs) has received particular attention during the last decades by using specific materials which promote P adsorption/precipitation phenomena. Recent studies have shown an interest in using apatite materials to promote P precipitation onto their surface. About ten years of experiments at different scales (laboratory, pilot, full scale) have passed. The process is now open in France. This paper presents the first design recommendations according ...

  11. The investigation of desired product properties of polycaprolactone-hydroxy apatite composites for tissue engineering applications

    OpenAIRE

    Küçükgöksel, Yelda; , Serap Cesur

    2014-01-01

    Biomaterials are used to perform or support the function of living tissues and contact with body fluids [1-3]. For temporary implants, biodegradation products of scaffolds have to be compatible with the body, and biodegradation time must be sufficient for regeneration of the tissue [4,5]. The aim of this study is to produce composites with improved product properties by using Polycaprolactone (PCL, hydrophobic and long biodegradation time) and Hydroxy apatite (HA, weak mechanical properties) ...

  12. The thermal history of the Bowen Basin: a comparison of apatite fission track analysis and vitrinite reflectance

    International Nuclear Information System (INIS)

    Vitrinite reflectance and apatite fission-track analysis (AFTA) are two techiques widely used to assess paleotemperatures of the order of 20-120 deg.C. in sedimentary basins. Whereas vitrinite reflectance is essentially a qualitative technique that gives an integrated measure of the entire thermal history, AFTA can reveal information on the variation of paleotemperatures through time because fission-tracks in apatite are continually produced throughout geological time. An apatite fission track study of the Upper Permian units of the Bowen Basin has offered the opportunity to compare the two paleotemperature indicators and place constraints on the timing of maximum paleotemperatures. The regional pattern of apatite fission-track ages closely coincides with the vitrinite reflectance indicating that maximum paleotemperatures have varied across the Basin with the central region of the Bowen Basin experiencing highest paleotemperatures. The reduction in apatite reflectance fission-track age with increasing reflectance represents the progressive annealing at temperatures around 60-120 deg. C. of those fission-tracks formed prior to the time of maximum temperatures. In those samples giving the youngest apatite fission-track ages all tacks were totally annealed at this time, and the fission-track age in these samples, in the range 90-120 Myr, indicate the time of cooling from the thermal maximum in the Early Cretaceous. 1 ref

  13. Hanford 100-N Area In Situ Apatite and Phosphate Emplacement by Groundwater and Jet Injection: Geochemical and Physical Core Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Szecsody, James E.; Vermeul, Vincent R.; Fruchter, Jonathan S.; Williams, Mark D.; Rockhold, Mark L.; Qafoku, Nikolla; Phillips, Jerry L.

    2010-07-01

    The purpose of this study is to evaluate emplacement of phosphate into subsurface sediments in the Hanford Site 100-N Area by two different technologies: groundwater injection of a Ca-citrate-PO4 solution and water-jet injection of sodium phosphate and/or fish-bone apatite. In situ emplacement of phosphate and apatite adsorbs, then incorporates Sr-90 into the apatite structure by substitution for calcium. Overall, both technologies (groundwater injection of Ca-citrate-PO4) and water-jet injection of sodium phosphate/fish-bone apatite) delivered sufficient phosphate to subsur¬face sediments in the 100-N Area. Over years to decades, additional Sr-90 will incorporate into the apatite precipitate. Therefore, high pressure water jetting is a viable technology to emplace phosphate or apatite in shallow subsurface sediments difficult to emplace by Ca-citrate-PO4 groundwater injections, but further analysis is needed to quantify the relevant areal extent of phosphate deposition (in the 5- to 15-ft distance from injection points) and cause of the high deposition in finer grained sediments.

  14. Search for stable energy levels in materials exhibiting strong anomalous fading: The case of apatites

    International Nuclear Information System (INIS)

    The thermally assisted OSL signal resulting from very deep traps was studied in the case of three fluorapatite samples, one chlorapatite as well as one collophanite cryptocrystalline carbonite phosphorite sample of various origins. Intense thermally assisted OSL signal was monitored while stimulating at 200 °C in all samples subjected to the present study, indicating the prevalence of the existence of these very deep traps. Anomalous fading effect is ubiquitous for all TL and OSL signals of all apatite samples subjected to the present study. The anomalous fading of the thermally assisted OSL signal arising from very deep traps is strongly differentiated from the anomalous fading of electron trap excited at temperatures below 500 °C. The thermally assisted OSL signal arising from very deep traps was found to clearly be more stable, showing much less anomalous fading over time. The possible implications of this finding in dating of both apatites and feldspars are also briefly discussed. - Highlights: • All apatite samples of the present study yield strong thermally assisted OSL (TA-OSL) signal. • In all cases, TA-OSL signal is much more stable compared to TL and conventional OSL, based on the corresponding anomalous fading rates. • This experimental feature could be extremely beneficial for luminescence dating

  15. Biomimetic Deposition of Apatite on Surface Chemically Modified Porous NiTi Shapememory Alloy

    Science.gov (United States)

    Wu, S. L.; Liu, X. M.; Chung, C. Y.; Chu, Paul K.; Chan, Y. L.; Yeung, K. W. K.; Chu, C. L.

    Porous NiTi shape memory alloy (SMA) with 48% porosity and an average pore size of 50-800 μm was synthesized by capsule-free hot isostatic pressing (CF-HIP). To enhance the surface bioactivity, the porous NiTi SMA was subjected to H2O2 and subsequent NaOH treatment. Scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy analyses revealed that a porous sodium titanate (Na2TiO3) film had formed on the surface of the porous NiTi SMA. An apatite layer was deposited on this film after immersion in simulated body fluid at 37°C, while no apatite could be found on the surface of the untreated porous NiTi SMA. The formation of the apatite layer infers that the bioactivity of the porous NiTi SMA may be enhanced by surface chemical treatment, which is favorable for its application as bone implants.

  16. Bioactivity of hydrothermal-electrochemically deposited apatite in vitro and in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Ban, S.; Harada, A.; Hasegawa, J. [Aichi-Gakuin Univ., Nagoya (Japan). Dept. of Dental Material Science; Arimoto, N. [Aichi-Gakuin Univ., Nagoya (Japan). Dept. of Operative Dentistry; Maruno, S. [Nagoya Inst. of Tech. (Japan). Dept. of Electrical and Computer Engineering

    2001-07-01

    Hydroxyapatite needles were formed on pure titanium plates using the hydrothermal-electrochemical method in an autoclave with two electrodes. The current was kept at 12.5 mA/cm{sup 2} for 1 h in an electrolyte containing Ca and phosphate ions maintained at 100, 150, and 200 C. Titanium plates coated with the hydrothermal-electrochemically deposited apatite at 100 C showed the largest weight gain after immersion in a simulated body fluid at 37 C for 3-27 weeks. Furthermore, the specimens coated at 100 C showed the largest weight loss after immersion in 0.01N HCl solution for 1 - 16 hours. There were no significant differences in the pull-out bonding strength of titanium bars coated at 100, 150, and 200 C to rabbit femora after 3-week implantation. All the hydrothermal-electrochemically deposited apatite showed an excellent biocompatibility. The new bone grew into the boundary between titanium substrate and deposited apatite from the outer surface. At 3-week implantation, the boundary at 100 C was completely filled with the new bone whereas that at 200 C was not yet filled with it. (orig.)

  17. Study of nanobiomaterial hydroxyapatite in simulated body fluid: Formation and growth of apatite

    Energy Technology Data Exchange (ETDEWEB)

    Chavan, Pradnya N.; Bahir, Manjushri M.; Mene, Ravindra U.; Mahabole, Megha P. [School of Physical Sciences, SRTM University, Nanded 431606 (India); Khairnar, Rajendra S., E-mail: rk2kin@yahoo.co [School of Physical Sciences, SRTM University, Nanded 431606 (India)

    2010-04-15

    Hydroxyapatite (HAp) is main mineral component of hard tissues. It is widely used in biomedical applications due to its excellent bioactivity and biocompatibility. Nanosized HAp is synthesized by wet chemical process. The synthesized HAp is characterized by XRD, FTIR, AFM and SEM for structural, morphological and functional groups analysis. The Simulated Body Fluid (SBF) is prepared by using chlorides, carbonates, oxides, and sulphates of alkali metals at 37 deg. C. The ion exchange process is carried out to exchange calcium cation by sodium and potassium. The pure HAp and ion exchanged HAp pellets are used as source of nucleating agent for apatite layer formation, in SBF maintained at 37 deg. C using incubator for different periods of time to study the bioactivity. The dielectric study is carried out on incubated pure and ion exchanged HAp pellets. XRD analysis confirms the hexagonal phase of hydroxyapatite. FTIR shows the presence of functional groups. SEM observations reveal that the growth of highly porous apatite layer on HAp surface increases with time. The dielectric constant is found to be in the range 3-12. It is seen that the synthesized HAp bioceramic nano material not only supports the growth of apatite layer but also accelerates the growth onto itself.

  18. Formation of Porous Apatite Layer during In Vitro Study of Hydroxyapatite-AW Based Glass Composites

    Directory of Open Access Journals (Sweden)

    Pat Sooksaen

    2015-01-01

    Full Text Available This research discussed the fabrication, characterization, and in vitro study of composites based on the mixture of hydroxyapatite powder and apatite-wollastonite (AW based glass. AW based glass was prepared from the SiO2-CaO-MgO-P2O5-CaF2 glass system. This study focuses on the effect of composition and sintering temperature that influences the properties of these composites. Microstructural study revealed the formation of apatite layer on the composite surfaces when immersed in simulated body fluid (SBF solution at 37°C. Composites containing ≥50 wt% AW based glass showed good bioactivity after 7 days of immersion in the SBF. A porous calcium phosphate (potentially hydroxycarbonate apatite, HCA layer formed at the SBF-composite interface and the layer became denser at longer soaking period, for periods ranging from 7 to 28 days. Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES analysis showed that early stage of soaking occurred with the release of Ca and Si ions from the composites and the decrease of P ions with slow exchange rate.

  19. In vivo bioactivity of titanium and fluorinated apatite coatings for orthopaedic implants: a vibrational study

    Science.gov (United States)

    Taddei, Paola; Tinti, Anna; Reggiani, Matteo; Monti, Patrizia; Fagnano, Concezio

    2003-06-01

    The bone integration of implants is a complex process which depends on chemical composition and surface morphology. To accelerate osteointegration, metal implants are coated with porous metal or apatites which have been reported to increase mineralisation, improving prosthesis fixation. To study the influence of composition and morphology on the in vivo bioactivity, titanium screws coated by Plasma Flame Spraying (PFS) with titanium or fluorinated apatite (K690) were implanted in sheep tibia and femur for 10 weeks and studied by micro-Raman and IR spectroscopy. The same techniques, together with thermogravimetry, were used for characterising the pre-coating K690 powder. Contrary to the manufacturer report, the K690 pre-coating revealed to be composed of a partially fluorinated apatite containing impurities of Ca(OH) 2 and CaCO 3. By effect of PFS, the impurities were decomposed and the crystallinity degree of the coating was found to decrease. The vibrational spectra recorded on the implanted screws revealed the presence of newly formed bone; for the K690-coated screws at least, a high level of osteointegration was evidenced.

  20. Bioactive coatings on Portland cement substrates: Surface precipitation of apatite-like crystals

    Energy Technology Data Exchange (ETDEWEB)

    Gallego, Daniel [Biomedical Engineering Department, Ohio State University, 1080 Carmack Road, 270 Bevis Hall, Columbus (OH) - 43210 (United States); Higuita, Natalia [Biomedical Engineering Department, Ohio State University, 1080 Carmack Road, 270 Bevis Hall, Columbus (OH) - 43210 (United States); Grupo de Investigacion en Ingenieria Biomedica CES-EIA (GIBEC), Carrera 43 A No. 52 Sur - 99, Sabaneta (Colombia); Garcia, Felipe [Grupo de Investigacion en Ingenieria Biomedica CES-EIA (GIBEC), Carrera 43 A No. 52 Sur - 99, Sabaneta (Colombia); Ferrell, Nicholas [Biomedical Engineering Department, Ohio State University, 1080 Carmack Road, 270 Bevis Hall, Columbus (OH) - 43210 (United States); Hansford, Derek J. [Biomedical Engineering Department, Ohio State University, 1080 Carmack Road, 270 Bevis Hall, Columbus (OH) - 43210 (United States)], E-mail: hansford.4@osu.edu

    2008-04-01

    We report a method for depositing bioactive coatings onto cement materials for bone tissue engineering applications. White Portland cement substrates were hydrated under a 20% CO{sub 2} atmosphere, allowing the formation of CaCO{sub 3}. The substrates were incubated in a calcium phosphate solution for 1, 3, and 6 days (CPI, CPII, and CPIII respectively) at 37 deg. C to induce the formation of carbonated apatite. Cement controls were prepared and hydrated with and without CO{sub 2} atmosphere (C+ and C- respectively). The presence of apatite-like crystals was verified by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The substrate cytocompatibility was evaluated via SEM after 24 hour cell cultures. SEM revealed the presence Ca(OH){sub 2} on C-, and CaCO{sub 3} on C+. Apatite-like crystals were detected only on CPIII, confirmed by phosphorus EDS peaks only for CPIII. Cells attached and proliferated similarly well on all the substrates except C-. These results prove the feasibility of obtaining biocompatible and bioactive coatings on Portland cement for bone tissue engineering applications.

  1. Combustible gases of deep levels of the Yuksporskiy apatite-nepheline field (Khibiny)

    Energy Technology Data Exchange (ETDEWEB)

    Pripachkin, V.A.

    1983-01-01

    Intensification of extraction of apatite-nepheline raw material and related development of deep levels of apatite fields require studies of the factors impairing safe mining operations. There are two viewpoints regarding the source of gas in the rocks: one refutes the existence of deep underflow of gases, the other proposes it. A study was made ofthe gases in the opened and closed pores. A technique is described for taking and processing the samples, and laboratory studies. A study was mainly made of the content of hydrogen, methane, carbon monoxide and dioxide, and single studies of a number of other components (helium, heavy hydrocarbons). As a result of gas metric studies, the confinement of increased content of gas of the enclosed pores of ''sorbed'' and ''free'' to the same sections was established. An increased content of gases was noted in the surrounding rocks through wells stripping the ore body, in the approach to its boundaries. The Yukstorskiy field can be divided into three sections with different content of gases by depth. The first up to depth 120-300 m where increase in the gas content is confined to the ijolite-urtite complex, the second the apatite ore body where increased contents of gas can be encountered only in single samples, and the third subore massif urtites are characterized by the highest content of gases where especial attention is required for observance of the safety rules of mining operations.

  2. Effect of Apatite Nanoparticles on DNA and AgNOR of Bel-7402 Hepatocellular Carcinoma

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The effect of apatite nanoparticles on proliferation potential and biological behaviour of the human hepatocellular carcinoma in vitro were investigated. After the treatment of Bel- 7402 hepatocellular carcinoma cells with apatite nanoparticles at a concentration of 5 × 10-4 mmol/ L for 4days, Feulgen and AgNOR stain were conducted and the specimens were observed by microscope. The DNA and AgNOR were quantified with image analysis techniques. It was found that there was a significant decrease of the DNA content (58.62 ± 6.52) in the nanoparticles treated group compared to the control (78.21 ± 4.17). It was further found that there was a decrease in the number of AgNOR granules in the nanoparticle treated group (7.41 ± 1.02) compared to the control group (9.95± 0.28). The experimental results showed that apatite nanoparticles could decrease the DNA reproductive activity and the rRNA synthesis in Bel-7402 hepatocellular carcinoma cells.

  3. Fission-track dating of apatite and zircon: An interlaboratory comparison

    Science.gov (United States)

    Naeser, C.W.; Zimmermann, R.A.; Cebula, G.T.

    1981-01-01

    Apatite and zircon separates from the Fish Canyon Tuff (K-Ar age, 27.9??0.7 Myr), San Juan Mtns., Colorado, have been given to over 50 laboratories for fission-track dating. Nineteen laboratories have reported fission-track ages that they have determined for apatites. Nine laboratories have reported their analysis of the zircons. The principal difference between the results reported by the laboratories reflects their choice of the decay constant. The laboratories which use a value of ??f ??? 7.0 ?? 10-17 yr-1 for the spontaneous-fission decay constant of 238U, report an average age for the apatite of 28.5??0.7 Myr, and those using ??f ??? = 8.4 ?? 10-17 yr-1 report an average age of 23.6??1.0 Myr. The average fission-track age for the zircons is 28.4??0.7 Myr. Only laboratories which use ??f ??? 7.0 ?? 10-17 yr-1 reported zircon data. ?? 1981.

  4. Search for stable energy levels in materials exhibiting strong anomalous fading: The case of apatites

    Energy Technology Data Exchange (ETDEWEB)

    Polymeris, George S., E-mail: polymers@auth.gr [Laboratory of Radiation Applications and Archaeological Dating, Department of Archaeometry and Physicochemical Measurements, ‘Athena’—Research and Innovation Center in Information, Communication and Knowledge Technologies, Kimmeria University Campus, GR-67100 Xanthi (Greece); Solid State Physics Section, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Giannoulatou, Valeria; Sfampa, Ioanna K. [Nuclear Physics Laboratory, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Tsirliganis, Nestor C. [Laboratory of Radiation Applications and Archaeological Dating, Department of Archaeometry and Physicochemical Measurements, ‘Athena’—Research and Innovation Center in Information, Communication and Knowledge Technologies, Kimmeria University Campus, GR-67100 Xanthi (Greece); Kitis, George [Nuclear Physics Laboratory, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

    2014-09-15

    The thermally assisted OSL signal resulting from very deep traps was studied in the case of three fluorapatite samples, one chlorapatite as well as one collophanite cryptocrystalline carbonite phosphorite sample of various origins. Intense thermally assisted OSL signal was monitored while stimulating at 200 °C in all samples subjected to the present study, indicating the prevalence of the existence of these very deep traps. Anomalous fading effect is ubiquitous for all TL and OSL signals of all apatite samples subjected to the present study. The anomalous fading of the thermally assisted OSL signal arising from very deep traps is strongly differentiated from the anomalous fading of electron trap excited at temperatures below 500 °C. The thermally assisted OSL signal arising from very deep traps was found to clearly be more stable, showing much less anomalous fading over time. The possible implications of this finding in dating of both apatites and feldspars are also briefly discussed. - Highlights: • All apatite samples of the present study yield strong thermally assisted OSL (TA-OSL) signal. • In all cases, TA-OSL signal is much more stable compared to TL and conventional OSL, based on the corresponding anomalous fading rates. • This experimental feature could be extremely beneficial for luminescence dating.

  5. Bone-like apatite coating on functionalized poly(etheretherketone) surface via tailored silanization layers technique.

    Science.gov (United States)

    Zheng, Yanyan; Xiong, Chengdong; Zhang, Shenglan; Li, Xiaoyu; Zhang, Lifang

    2015-10-01

    Poly(etheretherketone) (PEEK) is a rigid semi-crystalline polymer with outstanding mechanical properties, bone-like stiffness and suitable biocompatibility that has attracted much interest as a biomaterial for orthopedic and dental implants. However, the bio-inert surface of PEEK limits its biomedical applications when direct osteointegration between the implants and the host tissue is desired. In this work, -PO4H2, -COOH and -OH groups were introduced on the PEEK surface by further chemical treatments of the vinyl-terminated silanization layers formed on the hydroxylation-pretreated PEEK surface. Both the surface-functionalized and pristine specimens were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and water contact angle measurements. When placed in 1.5 strength simulated body fluid (SBF) solution, apatite was observed to form uniformly on the functionalized PEEK surface and firmly attach to the substrate. The characterized results demonstrated that the coating was constituted by poorly crystallized bone-like apatite and the effect of surface functional groups on coating formation was also discussed in detail. In addition, in vitro biocompatibility of PEEK, in terms of pre-osteoblast cell (MC3T3-E1) attachment, spreading and proliferation, was remarkably enhanced by the bone-like apatite coating. Thus, this study provides a method to enhance the bioactivity of PEEK and expand its applications in orthopedic and dental implants. PMID:26117784

  6. Alpha and thermal annealing of isolated defects in apatite and perovskite type materials

    International Nuclear Information System (INIS)

    In general, energy losses by α-particles occur predominantly through ionisation and coulombic interactions while recoil nuclei dissipate energy by elastic collisions on the host nuclei. This latter process results in atom displacements, which might produce a crystalline to amorphous transition by accumulation of isolated defects. In addition, α-emissions produced helium gas can diffuse interstitially through the lattice or induce swelling and constraints leading to possible micro-cracking. Our studies are dealing with these two aspects of the nuclear waste storage problems, in different matrices such as fluoro-apatites, britholite and perovskite. α-annealing was observed by RBS-Channeling techniques on single crystal materials. The α-dose needed to anneal half of the defects created is only of the order of 2.1015 He/cm2. At the equilibrium creation-recovery, it leads to less than 10% of disorder in the fluoro-apatite crystalline phase. Then, natural apatites will keep their crystallinity over a long period of actinide storage thanks to self α-annealing. The disorder level is independent of the radioactive decay time of the actinide isotope since the α-flux is always proportional to the defect creation rate. In the case of polycrystalline britholite (Ca9Nd(PO4)5SiO4F2), the α-remediation effect was investigated using in-situ TEM techniques. First experiments show that α-annealing is still operating in such britholites but this effect is less efficient than in fluoro-apatite. As far as the perovskite SrTiO3 is concerned, RBS on a single crystal was able to show that α-annealing is of very low efficiency whereas the thermal recovery seems very important. The helium diffusion rate was determined by the measurement of the thermal broadening of implanted He profiles with ERDA technique using 8.5 MeV carbon ions. In fluoro-apatite single crystals, for low He concentration, the diffusion rate is too low to avoid He accumulation. At higher concentration, the

  7. Ion microprobe U-Pb dating and strontium isotope analysis of biogenic apatite

    Science.gov (United States)

    Sano, Y.; Toyoshima, K.; Takahata, N.; Shirai, K.

    2012-12-01

    Conodonts are micro-fossils chemically composed of apatite which occurred in the body of one animal. They are guide fossils to show formation ages of sedimentary sequences with the highest resolution [1] and good samples to verify the dating method. We developed the ion microprobe U-Pb dating of apatite [2] and applied the method to a Carboniferous conodont [3] by using a SHRIMP II installed at Department of Earth and Planetary Sciences, Hiroshima University. Recently we have developed the NanoSIMS U-Pb dating method and successfully measured the formation ages of monazite [4] and zircon [5] at Atmosphere and Ocean Research Institute, University of Tokyo. In this work we carried out the NanoSIMS U-Pb dating of biogenic apatite such as conodont. Since the spot size of NanoSIMS is smaller than SHRIMP II, it is easier to have multi-spots on the single fragment of biogenic apatite. Based on the isochron method of U-Pb system, we have calculated the formation ages. They are consistent with those in literature. In order to study the chemical evolution of ocean during the past 600 Million years, strontium isotopes (87Sr/86Sr) of fossil marine carbonate such as coral skeletons and foraminifera tests were measured and compiled [6]. However they are not robust when the age is older than 500Ma, partly due to post-depositional histories. Apatite is more stable and more resistant to the alteration than carbonate [7]. Recently we have developed the method of NanoSIMS strontium isotopic analysis of a fish otolith, which composed of aragonite [8]. In this work we carried out the strontium isotopic analysis of biogenic apatite. The advantage of the ion microprobe technique over the TIMS (thermal ionization mass spectrometer) and MC-ICP-MS (multi-collector inductively coupled argon plasma mass spectrometer) method is preservation of the important textural context and to provide an opportunity for other simultaneous analytical work with high spatial resolution. This is the case for

  8. Combining apatite fission track and He thermochronology to constrain thermal histories

    Science.gov (United States)

    Persano, C.; Stuart, F.; Bishop, P.

    2003-04-01

    Apatite fission track thermochronometry (AFTT) has proved an invaluable tool for determining the cooling histories of rocks in the shallow crust. Quantitative models for the time and temperature dependence of the fission track annealing process in apatite demostrate that the combination of fission track apparent age and track length distribution provides a continuous record of the thermal history of the samples from 120 to 60^oC, and possibly, to lower temperatures. However the sensitivity of the technique is poorly constrained below 70-80^oC because annealing rates are slow. The apatite (U-Th)/He system is sensitive to temperatures between 80 and 40^oC irrespective of apatite chemistry, and presents a way to test the ability of AFTT to determine thermal histories below 80^oC. Here we present a novel way of combining apatite fission track and (U-Th)/He data that narrows the number of possible thermal histories and provides better constraints on the landscape evolution of a particular region. We use as an example the southeastern Australia passive margin in NSW, an area where post break-up landscape evolution is poorly resolved despite an extensive fission track database. Fission track and (U-Th)/He ages have been measured on 16 apatite samples from two coast perpendicular traverses across the coastal plain, up the escarpment onto the plateau. The fission track data are modelled using AFTSolve and the individual thermal histories which fit the data are used as parameters for forward modelling the apatite He ages. Only the thermal histories that produce the measured He age, within uncertainty, are considered. For each sample, the choosen time-temperature paths show the same peculiar characteristics, narrowing considerably the number of possible cooling scenarios. This combination shows that the AFT/derived thermal histories for temperatures between 60 to 40^oC may be inconsistent with the (U-Th)/He ages, suggesting that the annealing process at this temperatures

  9. The increase of apatite layer formation by the poly(3-hydroxybutyrate) surface modification of hydroxyapatite and β-tricalcium phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Szubert, M., E-mail: mm.szubert@gmail.com [Faculty of Chemical Technology, Poznan University of Technology, Poznan (Poland); Adamska, K. [Faculty of Chemical Technology, Poznan University of Technology, Poznan (Poland); Szybowicz, M. [Faculty of Technical Physics, Poznan University of Technology, Poznan (Poland); Jesionowski, T. [Faculty of Chemical Technology, Poznan University of Technology, Poznan (Poland); Buchwald, T. [Faculty of Technical Physics, Poznan University of Technology, Poznan (Poland); Voelkel, A. [Faculty of Chemical Technology, Poznan University of Technology, Poznan (Poland)

    2014-01-01

    The aim of this study was the surface modification of hydroxyapatite and β-tricalcium phosphate by poly(3-hydroxybutyrate) grafting and characterization of modificates. The bioactivity examination was carried out by the determination to grow an apatite layer on modified materials during incubation in simulated body fluid at 37 °C. The additional issue taken up in this paper was to investigate the influence of fluid replacement. The process of the surface modification of biomaterials was evaluated by means of infrared and Raman spectroscopy. Formation of the apatite layer was assessed by means of scanning electron microscopy and confirmed by energy dispersive, Raman and Fourier transformed infrared spectroscopy. During exposure in simulated body fluid, the variation of the zeta potential, pH measurement and relative weight was monitored. Examination of scanning electron microscopy micrographs suggests that modification of hydroxyapatite and β-tricalcium phosphate by poly(3-hydroxybutyrate) significantly increases apatite layer formation. Raman spectroscopy evaluation revealed that the formation of the apatite layer was more significant in the case of hydroxyapatite modificate, when compared to the β-tricalcium phosphate modificate. Both modificates were characterized by stable pH, close to the natural pH of human body fluids. Furthermore, we have shown that a weekly changed, simulated body fluid solution increases apatite layer formation. - Highlights: • Surface modification of HA and β-TCP was performed by PHB grafting. • The growth of apatite layer on materials was examined in simulated body fluid (SBF). • The bioactivity of obtained materials was proved. • The replacement of SBF solution plays an important role in the process of apatite formation.

  10. The increase of apatite layer formation by the poly(3-hydroxybutyrate) surface modification of hydroxyapatite and β-tricalcium phosphate

    International Nuclear Information System (INIS)

    The aim of this study was the surface modification of hydroxyapatite and β-tricalcium phosphate by poly(3-hydroxybutyrate) grafting and characterization of modificates. The bioactivity examination was carried out by the determination to grow an apatite layer on modified materials during incubation in simulated body fluid at 37 °C. The additional issue taken up in this paper was to investigate the influence of fluid replacement. The process of the surface modification of biomaterials was evaluated by means of infrared and Raman spectroscopy. Formation of the apatite layer was assessed by means of scanning electron microscopy and confirmed by energy dispersive, Raman and Fourier transformed infrared spectroscopy. During exposure in simulated body fluid, the variation of the zeta potential, pH measurement and relative weight was monitored. Examination of scanning electron microscopy micrographs suggests that modification of hydroxyapatite and β-tricalcium phosphate by poly(3-hydroxybutyrate) significantly increases apatite layer formation. Raman spectroscopy evaluation revealed that the formation of the apatite layer was more significant in the case of hydroxyapatite modificate, when compared to the β-tricalcium phosphate modificate. Both modificates were characterized by stable pH, close to the natural pH of human body fluids. Furthermore, we have shown that a weekly changed, simulated body fluid solution increases apatite layer formation. - Highlights: • Surface modification of HA and β-TCP was performed by PHB grafting. • The growth of apatite layer on materials was examined in simulated body fluid (SBF). • The bioactivity of obtained materials was proved. • The replacement of SBF solution plays an important role in the process of apatite formation

  11. Facile preparation of apatite-type lanthanum silicate by a new water-based sol–gel process

    Energy Technology Data Exchange (ETDEWEB)

    Yamagata, Chieko, E-mail: yamagata@ipen.br [Nuclear and Energy Research Institute – Instituto de Pesquisas Energéticas e Nucleares – CCTM (Centro de Ciência e Tecnologia de Materiais), São Paulo (Brazil); Elias, Daniel R.; Paiva, Mayara R.S.; Misso, Agatha M.; Castanho, Sonia R.H. Mello [Nuclear and Energy Research Institute – Instituto de Pesquisas Energéticas e Nucleares – CCTM (Centro de Ciência e Tecnologia de Materiais), São Paulo (Brazil)

    2013-06-01

    Highlights: ► We use a Na{sub 2}SiO{sub 3} waste solution as source of Si. ► We present a simple, rapid and low temperature method of lanthanum silicate apatite preparation. ► TEOS, a high cost reagent, was successfully substituted by a cheap price Na{sub 2}SiO{sub 3}, to obtain pure La{sub 9.56}(SiO{sub 4})6O{sub 2.33} lanthanum silicate apatite. - Abstract: In recent years, apatite-type lanthanum silicates ([Ln{sub 10−x}(XO{sub 4})6O{sub 3–1.5x}] (X = Si or Ge)) have been studied for use in SOFC (solid oxide fuel cells), at low temperature (600–800 °C), due to its ionic conductivity which is higher than that of YSZ (Yttrium Stabilized Zirconia) electrolyte. For this reason they are very promising materials as solid electrolyte for SOFCs. Synthesis of functional nanoparticles is a challenge in the nanotechnology. In this work, apatite-type lanthanum silicate nanoparticles were synthesized by a water-based sol–gel process, i.e., sol–gel technique followed by chemical precipitation of lanthanum hydroxide on the gel of the silica. Na{sub 2}SiO{sub 3} waste solution was used as silica source. Spherical aerogel silica was prepared by acid catalyzed reaction, followed by precipitation of lanthanum hydroxide to obtain the precursor of apatite-type lanthanum silicate. Powders of apatite-type lanthanum silicate achieved from the precursor were characterized by thermal analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and specific surface area measurements (BET). The apatite phase was formed at 900 °C.

  12. Apatite-forming ability and magnetic properties of glass-ceramics containing zinc ferrite and calcium sodium phosphate phases

    International Nuclear Information System (INIS)

    Fine particles of zinc ferrite (ZnFe2O4) and calcium sodium phosphate [NaCaPO4] were crystallized in bulk x(ZnO, Fe2O3)(65-x)SiO220(CaO, P2O5)15Na2O (6 ≤ x ≤ 21 mol %) glassy matrix by heat treatment. Initial magnetization curves reveal that samples with x = 6 and 9 mol % zinc-iron oxide exhibit both ferrimagnetic and paramagnetic contributions, whereas, samples with x > 9 mol % zinc-iron oxide exhibit only ferrimagnetic contribution. This observation is supported by the disappearance of the electron paramagnetic resonance (EPR) absorption line centered at g ∼ 4.3 in samples with x > 9 mol % zinc-iron oxide. Apatite-forming ability of the glass-ceramic samples was investigated by examining apatite formation on the surface of the samples treated in simulated body fluid (SBF). Increase in apatite-forming ability was observed with an increase in zinc-iron oxide content. The results obtained have been used to understand the evolution of the apatite surface layer as a function of immersion time in SBF and glass-ceramic composition. A good correlation has also been observed between the magnetic nature of the samples and their apatite-forming ability. These materials are expected to find application as thermo-seeds in hyperthermia treatment of bone cancer.

  13. Geology, alteration, age, and origin of iron oxide-apatite deposits in Upper Eocene quartz monzonite, Zanjan district, NW Iran

    Science.gov (United States)

    Nabatian, Ghasem; Ghaderi, Majid; Corfu, Fernando; Neubauer, Franz; Bernroider, Manfred; Prokofiev, Vsevolod; Honarmand, Maryam

    2014-02-01

    Iron oxide-apatite deposits are present in Upper Eocene pyroxene-quartz monzonitic rocks of the Zanjan district, northwestern Iran. Mineralization occurred in five stages: (1) deposition of disseminated magnetite and apatite in the host rock; (2) mineralization of massive and banded magnetite ores in veins and stockwork associated with minor brecciation and calcic alteration of host rocks; (3) deposition of sulfide ores together with potassic alteration; (4) formation of quartz and carbonate veins and sericite, chlorite, epidote, silica, carbonate, and tourmaline alteration; and (5) supergene alteration and weathering. U-Pb dating of monazite inclusions in the apatite indicates an age of 39.99 ± 0.24 Ma, which is nearly coeval with the time of emplacement of the host quartz monzonite, supporting the genetic connection. Fluid inclusions in the apatite have homogenization temperatures of about 300 °C and oxygen isotopic compositions of the magnetite support precipitation from magmatic fluids. Late-stage quartz resulted from the introduction of a cooler, less saline, and isotopically depleted fluid. The iron oxide-apatite deposits in the Tarom area of the Zanjan district are typical of a magmatic-hydrothermal origin and are similar to the Kiruna-type deposits with respect to mineral assemblages, fabric and structure of the iron ores, occurrence of the ore bodies, and wall rock alteration.

  14. Microstructure and leach rates of apatite glass-ceramics as a host for Sr high-level liquid waste

    International Nuclear Information System (INIS)

    An apatite glass-ceramic wasteform with 21 wt% SrO loading was fabricated for immobilizing Sr high-level liquid waste. The normalized leach rates of Sr, K, Mo, Al, P, Si are 6.9x10-4, 1.09x10-1, 2.7x10-3, 3.22x10-2, 2.84x10-2, 3.26x10-2 g/m2 day, respectively. Component Fe in all leachates is not detectable in the 28-day static leaching test procedure in MCC-1. Instead of leaching, component Ca is adsorbed by testing samples. All the component Mo concentrates in the glass matrix of the well crystallized apatite glass-ceramics. For an apatite glass-ceramic wasteform, the optimum microstructure should be one in which poorly crystallized apatite crystallites distribute evenly in the glass phase. Perfect crystallization makes the crystal phase more stoichiometric and significantly changes the composition of the coexisting glass phase in the system, which, in our case, decreases the chemical stability of the apatite glass-ceramics

  15. Atomistic modelling study of lanthanide incorporation in the crystal lattice of an apatite

    International Nuclear Information System (INIS)

    Studies of natural and synthetic apatites allow to propose such crystals as matrix for nuclear waste storage. The neodymium substituted britholite, Ca9Nd(PO4)5(SiO4)F2. is a model for the trivalent actinide storage Neodymium can be substituted in two types of sites. The aim of this thesis is to compare the chemical nature of this two sites in fluoro-apatite Ca9(PO4)6F2 and then in britholite, using ab initio atomistic modeling. Two approaches are used: one considers the infinite crystals and the second considers clusters. The calculations of the electronic structure for both were performed using Kohn and Sham density functional theory in the local approximation. For solids, pseudopotentials were used, and wave functions are expanded in plane waves. For clusters, a frozen core approximation was used, and the wave functions are expanded in a linear combination of Slater type atomic orbitals. The pseudopotential is semi-relativistic for neodymium, and the Hamiltonian is scalar relativistic for the clusters. The validation of the solid approach is performed using two test cases: YPO4 and ScPO4. Two numerical tools were developed to compute electronic deformation density map, and calculate partial density of stases. A full optimisation of the lattice parameters with a relaxation of the atomic coordinates leads to correct structural and thermodynamic properties for the fluoro-apatite, compared to experience. The electronic deformation density maps do not show any significant differences. between the two calcium sites. but Mulliken analysis on the solid and on the clusters point out the more ionic behavior of the calcium in site 2. A neodymium substituted britholite is then studied. Neodymium location only induces local modifications in; the crystalline structure and few changes in the formation enthalpy. The electronic study points out an increase of the covalent character the bonding involving neodymium compared with the one related to calcium, particularly in the Nd

  16. Dose response of A-type carbonated apatites prepared under different conditions

    International Nuclear Information System (INIS)

    Irradiated A-type carbonated apatites with carbonate content ranging from 1.45% to 4.84% are studied by using electron paramagnetic resonance (EPR). The EPR spectra are mainly constituted of lines associated to axial CO2- species (gperp=2.0028 and gpar=1.9973) and orthorhombic CO3- species (g1=2.0170, g2=2.0090 and g3=2.0041). The production of CO2- species on gamma irradiation depends on the carbonate concentration and the hydroxyapatite stoichiometry. The lowest dose detection limit was achieved with stoichiometric samples and carbonate concentration of 3.7%

  17. Enhanced apatite formation on Ti metal heated in P{sub O2}-controlled nitrogen atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Masami, E-mail: masami@jfcc.or.jp; Hayashi, Kazumi, E-mail: k_hayashi@jfcc.or.jp; Kitaoka, Satoshi, E-mail: kitaoka@jfcc.or.jp

    2013-10-15

    The oxynitridation of biomedical titanium metal under a precisely regulated oxygen partial pressure (P{sub O2}) of 10{sup −14} Pa in nitrogen atmosphere at 973 K for 1 h strongly enhanced apatite formation compared with that on Ti heated in air. The factors governing the high apatite-forming ability are discussed from the viewpoint of the surface properties of Ti heated under a P{sub O2} of 10{sup −14} Pa in nitrogen atmosphere determined from X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and zeta potential measurements. Nitrogen (N)-doped TiO{sub 2} (interstitial N) was formed on pure Ti heated under a P{sub O2} of 10{sup −14} Pa in nitrogen atmosphere at 973 K. The XPS O1s main peak shifted toward a lower binding energy upon heating under a P{sub O2} of 10{sup −14} Pa. This shift may be due to the formation of oxygen vacancies. This Ti surface had a positive zeta potential of approximately 20 mV. According to time-of-flight secondary ion mass spectroscopy results, PO{sub 4}{sup 3−} ions were predominantly adsorbed on Ti soaked in simulated body fluid (SBF) after heat treatment, followed by calcium ions. It was concluded that the apatite formation kinetics can be described using the Avrami–Erofeev equation with an Avrami index of n = 2, which implies the instantaneous nucleation of apatite on the surface of Ti soaked in SBF after heat treatment at 973 K under a P{sub O2} of 10{sup −14} Pa. - Highlights: • Nitrogen-doped TiO{sub 2} was formed on Ti heated under a P{sub O2} of 10{sup −14} Pa. • Oxygen vacancy was existed on the outermost layer of nitrogen-doped TiO{sub 2}. • This nitrogen-doped TiO{sub 2} surface had a positive zeta potential of 20 mV. • PO{sub 4}{sup 3−} ions were predominantly adsorbed on the nitrogen-doped TiO{sub 2} soaked in SBF.

  18. SAXS study on the morphology of etched and un-etched ion tracks in apatite

    Directory of Open Access Journals (Sweden)

    Nadzri A.

    2015-01-01

    Full Text Available Natural apatite samples were irradiated with 185 MeV Au and 2.3 GeV Bi ions to simulate fission tracks. The resulting track morphology was investigated using synchrotron small angle x-ray scattering (SAXS measurements before and after chemical etching. We present preliminary results from the SAXS measurement showing the etching process is highly anisotropic yielding faceted etch pits with a 6-fold symmetry. The measurements are a first step in gaining new insights into the correlation between etched and unetched fission tracks and the use of SAXS as a tool for studying etched tracks.

  19. Corrosion res ance of stainless steels in media of nitric-acid decomposition of apatite

    International Nuclear Information System (INIS)

    Presented are results of investigation of corrosion resistance of stainless steels 06KhN28MDT, 08Kh21N6M2T, 08Kh22N5T and Kh18N10T in media initiating composition of pulp liquid phase of nitric acid decompositon of apatite (phosphoric acid, hydrofluoric acid and fluosilicic acid). Principle application possibility of economically-alloyed as to nickel the 08Kh21N62MT steels for the apparatus equipment of the process instead of highly alloyed 06KhN28MDT steel is established

  20. Contribution to the interpretation of flotability characteristics of the calcite/apatite system

    International Nuclear Information System (INIS)

    Studies of morfology and determinations of chemical composition of apatite and calcite samples from Jacupiranga, (SP), Brazil, and Itataia (CE), Brazil, were compared with results of microflotation tests. The microflotation tests were carried out with pure and mixture samples. The ores samples were characterized by X ray diffraction. The behavior of the same ores from other deposits was different of these same ores during microflotation. The flotability of calcite depends on its morphology; the MgO content is a less important variable. (Author)

  1. Emplacement time of Salai Patai carbonatite, Malakand, Pakistan, from fission track dating of zircon and apatite

    Energy Technology Data Exchange (ETDEWEB)

    Qureshi, A.A.; Khan, H.A. (N.E.D., Nilore, Islamabad (Pakistan). SSNTD-Lab.); Butt, K.A. (Atomic Energy Minerals Centre, Lahore (Pakistan))

    1991-01-01

    Based on fission track dating of zircon and apatite, the emplacement history of Salai Patai carbonatite has been traced. It has been estimated that the carbonatite was emplaced along the thrust plane associated with the Indian-Eurasian plate collision during the Oligocene period followed by some thermal/tectonic episode during Early Miocene. This negates the previous proposal that all carbonatites found in Pakistan are a part of a 200 km long alkaline province associated with the rifting of Peshawar Valley during Late Cretaceous or early tertiary. (author).

  2. Study on surface modification of porous apatite-wollastonite bioactive glass ceramic scaffold

    Science.gov (United States)

    Cao, Bin; Zhou, Dali; Xue, Ming; Li, Guangda; Yang, Weizhong; Long, Qin; Ji, Li

    2008-11-01

    Chitosan (CS) was used to modify the surface of apatite-wollastonite bioactive glass ceramic (AW GC) scaffold to prepare AW/CS composite scaffold. The in vitro bioactivity of the AW/CS composite scaffold was investigated by simulated body fluid (SBF) soaking experiment. Cell growth on the surface of the material was evaluated by co-culturing osteogenic marrow stromal cells (MSCs) of rabbits with the scaffold. The results showed that the compressive strength of AW GC scaffold was improved dramatically after being modified by CS, whereas the mineralization rate was delayed. MSCs can attach well on the surface of the composite scaffold.

  3. Bone-like apatite formation on HA/316L stainless steel composite surface in simulated body fluid

    Institute of Scientific and Technical Information of China (English)

    FAN Xin; CHEN Jian; ZOU Jian-peng; WAN Qian; ZHOU Zhong-cheng; RUAN Jian-ming

    2009-01-01

    HA/316L stainless steel(316L SS) biocomposites were prepared by hot-pressing technique. The formation of bone-like apatite on the biocomposite surfaces in simulated body fluid(SBF) was analyzed by digital pH meter, plasma emission spectrometer, scanning electron microscope(SEM) and energy dispersive X-ray energy spectrometer(EDX). The results indicate that the pH value in SBF varies slightly during the immersion. It is a dynamic process of dissolution-precipitation for the formation of apatite on the surface. With prolonging immersion time, Ca and P ion concentrations increase gradually, and then approach equilibrium. The bone-like apatite layer forms on the composites surface, which possesses benign bioactivity and favorable biocompatibility and achieves osseointegration, and can provide firm fixation between HA60/316L SS composite implants and human body bone.

  4. Study of the dissolution of three synthetic minerals: zirconolite, Y-britholite and mono-silicate fluor-apatite

    International Nuclear Information System (INIS)

    In this study, we were interested in the synthesis by natural sintering of three minerals analogue of natural rocks: zirconolite, Y-britholite and mono-silicated fluor-apatite. Cerium was used as an actinide surrogate. A simple physical characterization of the materials was made by X-ray diffraction and by measuring both densities and hardnesses. A static leaching test allowed determining the cerium immobilization capacity of the minerals. The most stable mineral was mono-silicated fluor-apatite, with a maximum amount of released cerium less than 2 %. For zirconolite and Y-britholite, this amount reached 15 and 18 % of the total cerium in the minerals, respectively. For the latter compounds, the cerium content in the materials was too weak, and the chosen synthesis method gave less satisfactory physicochemical mineral properties compared to those obtained for mono-silicated fluor-apatite. (authors)

  5. Gadolinium borosilicate glass-bonded Gd-silicate apatite: a glass-ceramic nuclear waste form for actinides

    International Nuclear Information System (INIS)

    A Gd-rich crystalline phase precipitated in a sodium gadolinium alumino-borosilicate glass during synthesis. The glass has a chemical composition of 45.4-31.1 wt% Gd2O3, 28.8-34.0 wt% SiO2,10.8-14.0 wt% Na2O, 4.3-5.9 wt% Al2O3, and 10.8-14.9 wt% B2O3. Backscattered electron images revealed that the crystals are hexagonal, elongated, acicular, prismatic, skeletal or dendritic, tens of μm in size, some reaching 200 μm in length. Electron microprobe analysis confirmed that the crystals are chemically homogeneous and have a formula of NaGd9(SiO4)6O2 with minor B substitution for Si. The X-ray diffraction pattern of this phase is similar to that of lithium gadolinium silicate apatite. Thus, this hexagonal phase is a rare earth silicate with the apatite structure. We suggest that this Gd-silicate apatite in a Gd-borosilicate glass is a potential glass-ceramic nuclear waste form for actinide disposition. Am, Cm and other actinides can easily occupy the Gd-sites. The potential advantages of this glass-ceramic waste form include: 1) both the glass and apatite can be used to immobilize actinides, 2) silicate apatite is thermodynamically more stable than the glass, 3) borosilicate glass-bonded Gd-silicate apatite is easily fabricated, and 4) the Gd is an effective neutron absorber.Copyright (2001) Material Research Society

  6. Possible secondary apatite fission track age standard from altered volcanic ash beds in the middle Jurassic Carmel Formation, Southwestern Utah

    Science.gov (United States)

    Kowallis, B.J.; Christiansen, E.H.; Everett, B.H.; Crowley, K.D.; Naeser, C.W.; Miller, D.S.; Deino, A.L.

    1993-01-01

    Secondary age standards are valuable in intra- and interlaboratory calibration. At present very few such standards are available for fission track dating that is older than Tertiary. Several altered volcanic ash beds occur in the Middle Jurassic Carmel Formation in southwestern Utah. The formation was deposited in a shallow marine/sabhka environment. Near Gunlock, Utah, eight ash beds have been identified. Sanidines from one of the ash beds (GUN-F) give a single-crystal laser-probe 40Ar/39Ar age of 166.3??0.8 Ma (2??). Apatite and zircon fission track ages range from 152-185 Ma with typically 15-20 Ma errors (2??). Track densities in zircons are high and most grains are not countable. Apatites are fairly common in most of the ash beds and have reasonable track densities ranging between 1.2-1.5 ?? 106 tracks/cm2. Track length distributions in apatites are unimodal, have standard deviations <1??m, and mean track lengths of about 14-14.5 ??m. High Cl apatites (F:Cl:OH ratio of 39:33:28) are particularly abundant and large in ash GUN-F, and are fairly easy to concentrate, but the concentrates contain some siderite, most of which can be removed by sieving. GUN-F shows evidence of some reworking and detriaal contamination based on older single grain 40Ar/39Ar analyses and some rounding of grains, but the apatite population appears to be largely uncontaminated. At present BJK has approximately 12 of apatite separate from GUN-F. ?? 1993.

  7. Apatite coated on organic polymers by biomimetic process: improvement in its adhesion to substrate by NaOH treatment.

    Science.gov (United States)

    Tanahashi, M; Yao, T; Kokubo, T; Minoda, M; Miyamoto, T; Nakamura, T; Yamamuro, T

    1994-01-01

    A dense, uniform and highly biologically active bone-like apatite layer can be formed in arbitrary thickness on any kind and shape of solid substrate surface by the following biomimetic method at ordinary temperature and pressure. First, a substrate is set in contact with particles of bioactive CaO SiO2 based glass soaked in a simulated body fluid (SBF) with inorganic ion concentrations nearly equal to those of human blood plasma. Second, the substrate is soaked in another solution with ion concentrations 1.5 times those of SBF (1.5 SBF). In the present study, organic polymer substrates treated with 5 M NaOH solution were subjected to the above mentioned biomimetic process. The induction periods for the apatite nucleation on polyethyleneterephthalate (PET), polymethylmethacrylate (PMMA), polyamide 6 (PA6), and polyethersulfone (PESF) substrates were reduced from 24 to 12 h with the NaOH treatment. The adhesive strength of the formed apatite layer were increased from 3.5 to 8.6 MPa, from 1.1 to 3.4 MPa, and from 0.6 to 5.3 MPa with the NaOH treatment, for PET, PMMA, and PA 6, respectively. It was assumed that highly polar groups, such as carboxyl and sulfinyl ones formed by the hydrolysis of an ester group on PET and PMMA and of an amide group on PA 6, or of a sulfonyl group on PESF with the NaOH treatment, attached a large number of hydrated silica dissolved from the glass particles, to accelerate the apatite nucleation, and also to form a strong bond with the apatite. The apatite-organic polymer composites thus obtained are expected to be useful as bone-repairing as well as soft tissue-repairing materials. PMID:8580541

  8. The role of the counter-ions present in syntheses on the thermal stabilization of strontium and/or calcium apatites

    Energy Technology Data Exchange (ETDEWEB)

    Melo da Silva, Leila; Santos Menezes, Daniela dos; Almeida, Luis Eduardo [Laboratório de Biomateriais – P" 2CEM, Universidade Federal de Sergipe, Av. Marechal Rondon, s/n, São Cristóvão, 49100-000 Sergipe (Brazil); Anselme, Karine; Dentzer, Joseph [Institut de Science des Matériaux de Mulhouse (IS2M), CNRS UMR7361, Université de Haute-Alsace, 15, rue Jean Starcky, BP 2488, 68057 Mulhouse (France); Araujo dos Santos, Euler, E-mail: euler@ufs.br [Laboratório de Biomateriais – P" 2CEM, Universidade Federal de Sergipe, Av. Marechal Rondon, s/n, São Cristóvão, 49100-000 Sergipe (Brazil)

    2015-09-15

    Highlights: • Counter-ions present in syntheses can affect thermal stabilization of apatites. • Ions with different charges and sizes can stabilize the apatite structure. • Co-substitution is an important way to design biomimetic hydroxyapatites. - Abstract: The goal of this work was to study the thermal stabilization of calcium apatites in which the Ca{sup 2+} ions were substituted for Sr{sup 2+} in increasing concentrations via ionic co-substitutions. Two distinct standard syntheses were proposed for comparative purposes: one using counter-ions that were not easily incorporated into the apatite structure (NH{sub 4}{sup +}/NO{sub 3}{sup −}) and one using counter-ions that can be easily incorporated into the structure (Na{sup +}/Cl{sup −}). After calcination, only the apatites synthesized in the presence of NH{sub 4}{sup +}/NO{sub 3}{sup −} presented phase transformation. In contrast, the apatites synthesized in the presence of Na{sup +}/Cl{sup −} formed a solid solution after calcination, with Na{sup +}, Ca{sup 2+}, Sr{sup 2+} and Cl{sup −} sharing the same apatite lattice. Wavelength dispersive X-ray fluorescence spectroscopy (WDXRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and temperature-programmed desorption (TPD) techniques showed that the counter-ions present during the syntheses that are associated with CO{sub 3}{sup 2−} play an important role in the thermal stabilization of the apatites.

  9. Biomimetic growth and substrate dependent mechanical properties of bone like apatite nucleated on Ti and magnetron sputtered TiO2 nanostructure

    Science.gov (United States)

    Sarma, Bimal K.; Das, Apurba; Barman, Pintu; Pal, Arup R.

    2016-04-01

    This report presents findings on biomimetic growth of hydroxyapatite (HAp) nanocrystals on Ti and sputtered TiO2 substrates. The possibility of TiO2 nanostructure as candidate materials for future biomedical applications has been explored through the comparison of microstructural and mechanical properties of bone like apatite grown on Ti and nano-TiO2 surfaces. Raman spectroscopy and x-ray diffraction studies reveal formation of carbonate apatite with apparent domain size in the nanoscale range. A better interaction at the nano-TiO2/nano-HAp interface due to higher interfacial area could promote the growth of bone like apatite. The crystal phases, crystallinity, and surface morphology of nano-TiO2 are considered as parameters to understand the nucleation and growth of apatite with different mechanical properties at the nanoscale. The methodology of x-ray line profile analysis encompasses deconvolution of merged peaks by preserving broadening due to nanosized HAp aggregates. The Young’s modulus of bone like apatite exhibits crystallographic directional dependence which suggests the presence of elastic anisotropy in bone like apatite. The lattice contraction in the c-direction is associated with the degree of carbonate substitution in the apatite lattice. The role of residual stress is critical for the lattice distortion of HAp deposited at physiological conditions of temperature and pH of human blood plasma. The ion concentration is crucial for the uniformity, crystallinity, and mechanical behaviour of the apatite.

  10. The role of the counter-ions present in syntheses on the thermal stabilization of strontium and/or calcium apatites

    International Nuclear Information System (INIS)

    Highlights: • Counter-ions present in syntheses can affect thermal stabilization of apatites. • Ions with different charges and sizes can stabilize the apatite structure. • Co-substitution is an important way to design biomimetic hydroxyapatites. - Abstract: The goal of this work was to study the thermal stabilization of calcium apatites in which the Ca2+ ions were substituted for Sr2+ in increasing concentrations via ionic co-substitutions. Two distinct standard syntheses were proposed for comparative purposes: one using counter-ions that were not easily incorporated into the apatite structure (NH4+/NO3−) and one using counter-ions that can be easily incorporated into the structure (Na+/Cl−). After calcination, only the apatites synthesized in the presence of NH4+/NO3− presented phase transformation. In contrast, the apatites synthesized in the presence of Na+/Cl− formed a solid solution after calcination, with Na+, Ca2+, Sr2+ and Cl− sharing the same apatite lattice. Wavelength dispersive X-ray fluorescence spectroscopy (WDXRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and temperature-programmed desorption (TPD) techniques showed that the counter-ions present during the syntheses that are associated with CO32− play an important role in the thermal stabilization of the apatites

  11. Apatite as an indicator of fluid salinity: An experimental study of chlorine and fluorine partitioning in subducted sediments

    Science.gov (United States)

    Li, Huijuan; Hermann, Joerg

    2015-10-01

    In order to constrain the salinity of subduction zone fluids, piston-cylinder experiments have been conducted to investigate the partitioning behaviour of Cl and F in subducted sediments. These experiments were performed at H2O-undersaturated conditions with a synthetic pelite starting composition containing 800 ppm Cl, over a pressure and temperature range of 2.5-4.5 GPa and 630-900 °C. Repetitive experiments were conducted with 1900 ppm Cl + 1000 ppm F, and 2100 ppm Cl. Apatite represents the most Cl-abundant mineral phase, with Cl concentration varying in the range 0.1-2.82 wt%. Affinity for Cl decreases over the following sequence: aqueous fluid > apatite ⩾ melt > other hydrous minerals (phengite, biotite and amphibole). It was found that addition of F to the Cl-bearing starting composition significantly lowers the Cl partition coefficients between apatite and melt (DClAp-melt) and apatite and aqueous fluid (DClAp-aq). Cl-OH exchange coefficients between apatite and melt (KdCl-OHAp-melt) and apatite and aqueous fluid (KdCl-OHAp-aq) were subsequently calculated. KdCl-OHAp-melt was found to vary from 1 to 58, showing an increase with temperature and a decrease with pressure and displaying a regular decrease with increasing H2O content in melt. Mole fractions of Cl and OH in melt were calculated based on an ideal mixing model for H2O, OH, O, Cl and F. The Cl contents of other hydrous minerals (phengite, biotite and amphibole) fall between 200 and 800 ppm, with resultant Cl partition coefficients from 0.02 to 0.49, appearing independent of the bulk Cl and F content. Preliminary data from this study show that the partitioning behaviour of F is strongly in favour of apatite relative to melt and phengite, with DFAp-melt = 15-51. Apatites from representative eclogite facies metasediments were examined and found to have low Cl contents close to ∼100 ppm. Calculations using our experimentally determined KdCl-OHAp-aq of 0.004 at 2.5 GPa, 630 °C indicate a low

  12. The transantarctic mountains: A natural laboratory for apatite fission-track analysis. Results from Italian antarctic expeditions

    International Nuclear Information System (INIS)

    Apatite fission-track analysis has been applied to samples collected during the 1991/1992, 1993/1994 and 1996/1997 campaigns of the Italian Antarctic Project in the Transantarctic Mountains. Samples from the first two campaigns, collected in the area between the Mariner and the David Glaciers (northern Victoria Land), reveal that a Late Cretaceous uplift - denudation phase already identified in other sectors of the chain took place also in this region. They also confirm the occurrence of a more recent phase starting in the Late Paleocene. Offsets in apatite age profiles regarding samples collected further north during the third campaign reveal Cenozoic normal faulting with variable sense of offset

  13. Calibration of the Fluorine, Chlorine and Hydrogen Content of Apatites With the ChemCam LIBS Instrument

    Science.gov (United States)

    Meslin, P.-Y.; Cicutto, L.; Forni, O.; Drouet, C.; Rapin, W.; Nachon, M.; Cousin, A.; Blank, J. G.; McCubbin, F. M.; Gasnault, O.; Newsom, H.; Mangold, N.; Schroeder, S.; Sautter, V.; Maurice, S.; Wiens, R. C.

    2016-01-01

    Determining the composition of apatites is important to understand the behavior of volatiles during planetary differentiation. Apatite is an ubiquitous magmatic mineral in the SNC meteorites. It is a significant reservoir of halogens in these meteorites and has been used to estimate the halogen budget of Mars. Apatites have been identified in sandstones and pebbles at Gale crater by ChemCam, a Laser-Induced Breakdown Spectroscometer (LIBS) instrument onboard the Curiosity rover. Their presence was inferred from correlations between calcium, fluorine (using the CaF molecular band centered near 603 nm, whose detection limit is much lower that atomic or ionic lines and, in some cases, phosphorus (whose detection limit is much larger). An initial quantification of fluorine, based on fluorite (CaF2)/basalt mixtures and obtained at the LANL laboratory, indicated that the excess of F/Ca (compared to the stoichiometry of pure fluorapatites) found on Mars in some cases could be explained by the presence of fluorite. Chlorine was not detected in these targets, at least above a detection limit of 0.6 wt% estimated from. Fluorapatite was later also detected by X-ray diffraction (with CheMin) at a level of approx.1wt% in the Windjana drill sample (Kimberley area), and several points analyzed by ChemCam in this area also revealed a correlation between Ca and F. The in situ detection of F-rich, Cl-poor apatites contrasts with the Cl-rich, F-poor compositions of apatites found in basaltic shergottites and in gabbroic clasts from the martian meteorite NWA 7034, which were also found to be more Cl-rich than apatites from basalts on Earth, the Moon, or Vesta. The in situ observations could call into question one of the few possible explanations brought forward to explain the SNC results, namely that Mars may be highly depleted in fluorine. The purpose of the present study is to refine the calibration of the F, Cl, OH and P signals measured by the ChemCam LIBS instrument, initiated

  14. Nanodimensional and Nanocrystalline Apatites and Other Calcium Orthophosphates in Biomedical Engineering, Biology and Medicine

    Directory of Open Access Journals (Sweden)

    Sergey V. Dorozhkin

    2009-11-01

    Full Text Available Recent developments in biomineralization have already demonstrated that nanosized particles play an important role in the formation of hard tissues of animals. Namely, the basic inorganic building blocks of bones and teeth of mammals are nanodimensional and nanocrystalline calcium orthophosphates (in the form of apatites of a biological origin. In mammals, tens to hundreds nanocrystals of a biological apatite were found to be combined into self-assembled structures under the control of various bioorganic matrixes. In addition, the structures of both dental enamel and bones could be mimicked by an oriented aggregation of nanosized calcium orthophosphates, determined by the biomolecules. The application and prospective use of nanodimensional and nanocrystalline calcium orthophosphates for a clinical repair of damaged bones and teeth are also known. For example, a greater viability and a better proliferation of various types of cells were detected on smaller crystals of calcium orthophosphates. Thus, the nanodimensional and nanocrystalline forms of calcium orthophosphates have a great potential to revolutionize the field of hard tissue engineering starting from bone repair and augmentation to the controlled drug delivery devices. This paper reviews current state of knowledge and recent developments of this subject starting from the synthesis and characterization to biomedical and clinical applications. More to the point, this review provides possible directions of future research and development.

  15. Radiation effects in plutonium and carbonate co-doped calcium hydroxy apatite. An EPR study

    International Nuclear Information System (INIS)

    Electron paramagnetic resonance studies were conducted on synthetic calcium hydroxy apatite samples co-doped with 239Pu and carbonate ion. These investigations were carried out to assess the self-irradiation effects in bone and teeth on exposure to plutonium, as calcium hydroxy apatite is the major constituent of bone and teeth. On self-irradiation, in addition to the signal from O- ion arising from the radiolysis of hydroxide ion, EPR signals due to CO2-, PO22- and another signal assigned to surface O- ions were observed in the samples. In freshly quenched gamma irradiated samples, signals from CO3-, O-, PO22- and O2- ions were observed. The EPR signal of O2- ion shows a doublet splitting suggesting that O2- ion gets preferentially stabilized close to Pu4+. The radiation damage due to Pu4+ at Ca2+ sites, in the sample appears to be lower as compared to that due to external gamma-irradiation. Moreover, the alpha-dose in 239Pu doped samples has self-annealing effects. These are attributed to localized radiation damage due to alpha-particles compared to evenly distributed radical ions produced due to gamma-irradiation. (author)

  16. Preparation and biocompatibility evaluation of apatite/wollastonite-derived porous bioactive glass ceramic scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Hua; Ye Xiaojian; Li Jiashun, E-mail: ljsspine@163.co [Department of Orthopedic Surgery, Shanghai, Changzheng Hospital, Second Military Medical University, Shanghai (China)

    2009-08-15

    An apatite/wollastonite-derived (A/W) porous glass ceramic scaffold with highly interconnected pores was successfully fabricated by adding a plastic porosifier. The morphology, porosity and mechanical strength were characterized. The results showed that the glass ceramic scaffold with controllable pore size and porosity displayed open macropores. In addition, good in vitro bioactivity was found for the scaffold obtained by soaking it in simulated body fluid. Mesenchymal stem cells (MSCs) were cultured, expanded and seeded on the scaffold, and the adhesion and proliferation of MSCs were determined using MTT assay and environmental scanning electron microscopy (ESEM). The results revealed that the scaffold was biocompatible and had no negative effects on the MSCs in vitro. The in vivo biocompatibility and osteogenicity were investigated by implanting both the pure scaffold and the MSC/scaffold construct in rabbit mandibles and studying histologically. The results showed that the glass ceramic scaffold exhibited good biocompatibility and osteoconductivity. Moreover, the introduction of MSCs into the scaffold observably improved the efficiency of new bone formation, especially at the initial stage after implantation. However, the glass ceramic scaffold showed the same good biocompatibility and osteogenicity as the hybrid one at the later stage. These results indicate that porous bioactive scaffolds based on the original apatite-wollastonite glass ceramic fulfil the basic requirements of a bone tissue engineering scaffold.

  17. Preparation and biocompatibility evaluation of apatite/wollastonite-derived porous bioactive glass ceramic scaffolds.

    Science.gov (United States)

    Zhang, Hua; Ye, Xiao-Jian; Li, Jia-Shun

    2009-08-01

    An apatite/wollastonite-derived (A/W) porous glass ceramic scaffold with highly interconnected pores was successfully fabricated by adding a plastic porosifier. The morphology, porosity and mechanical strength were characterized. The results showed that the glass ceramic scaffold with controllable pore size and porosity displayed open macropores. In addition, good in vitro bioactivity was found for the scaffold obtained by soaking it in simulated body fluid. Mesenchymal stem cells (MSCs) were cultured, expanded and seeded on the scaffold, and the adhesion and proliferation of MSCs were determined using MTT assay and environmental scanning electron microscopy (ESEM). The results revealed that the scaffold was biocompatible and had no negative effects on the MSCs in vitro. The in vivo biocompatibility and osteogenicity were investigated by implanting both the pure scaffold and the MSC/scaffold construct in rabbit mandibles and studying histologically. The results showed that the glass ceramic scaffold exhibited good biocompatibility and osteoconductivity. Moreover, the introduction of MSCs into the scaffold observably improved the efficiency of new bone formation, especially at the initial stage after implantation. However, the glass ceramic scaffold showed the same good biocompatibility and osteogenicity as the hybrid one at the later stage. These results indicate that porous bioactive scaffolds based on the original apatite-wollastonite glass ceramic fulfil the basic requirements of a bone tissue engineering scaffold. PMID:19605959

  18. Synthesis and characterization of nanocrystalline apatites from solution modeling human blood

    Science.gov (United States)

    Solodyankina, Anna; Nikolaev, Anton; Frank-Kamenetskaya, Olga; Golovanova, Olga

    2016-09-01

    Present paper is devoted to the research of the calcification processes in the blood plasma of human body. Spontaneous crystallization from the solution modeling the inorganic part of the blood plasma has been carried out. Obtained precipitates were studied by the various instrumental methods (X-ray powder diffraction, Fourier-transformed infrared spectroscopy, scanning electron microscopy, electron probe microanalysis and gas-volumetric method). All gathered data allow to summarize that nonstoichiometric carbonated hydroxyapatite with low crystallinity (CSD lengths 18-28 nm), high water content and small amount of chlorine ion was obtained throughout the syntheses. Part of vacancies at the Ca sites varies from 0.17 to 0.87; the value of the Cat/(P + C) ratio-from 1.52 to 1.64 (where Cat = Ca2+ + Na+ + K+ + Mg2+). The poor crystallized synthetic apatites with high carbonate ion content (from 4.34 to 5.54 wt%) and c parameter (6.888-6.894 Å) are analogues of the apatites of the pathological cardiovascular deposits. They can be obtained from the solution modeling human blood plasma by the inorganic components with calcium phosphate supersaturation 25 and 50 and with 10 and 12 weeks experiment time.

  19. Histological Comparison in Rats between Carbonate Apatite Fabricated from Gypsum and Sintered Hydroxyapatite on Bone Remodeling

    Directory of Open Access Journals (Sweden)

    Yasunori Ayukawa

    2015-01-01

    Full Text Available Carbonate apatite (CO3Ap, the form of apatite found in bone, has recently attracted attention. The purpose of the present study was to histologically evaluate the tissue/cellular response toward the low-crystalline CO3Ap fabricated using a dissolution-precipitation reaction with set gypsum as a precursor. When set gypsum was immersed in a 100°C 1 mol/L Na3PO4 aqueous solution for 24 h, the set gypsum transformed into CO3Ap. Both CO3Ap and sintered hydroxyapatite (s-HAp, which was used as a control, were implanted into surgically created tibial bone defects of rats for histological evaluation. Two and 4 weeks after the implantation, histological sections were created and observed using light microscopy. The CO3Ap granules revealed both direct apposition of the bone matrix by osteoblasts and osteoclastic resorption. In contrast, the s-HAp granules maintained their contour even after 4 weeks following implantation which implied that there was a lack of replacement into the bone. The s-HAp granules were sometimes encapsulated with fibrous tissue, and macrophage polykaryon was occasionally observed directly apposed to the implanted granules. From the viewpoint of bone remodeling, the CO3Ap granules mimicked the bone matrix, suggesting that CO3Ap may be an appropriate bone substitute.

  20. Alternate dipping preparation of biomimetic apatite layers in the presence of carbonate ions

    International Nuclear Information System (INIS)

    The classical simulated body fluids method cannot be employed to prepare biomimetic apatites encompassing metallic ions that lead to very stable phosphates. This is the case for heavy metals such as uranium, whose presence in bone mineral after contamination deserves toxicological study. We have demonstrated that existing methods, based on alternate dipping into calcium and phosphate ions solutions, can be adapted to achieve this aim. We have also especially studied the impact of the presence of carbonate ions in the medium as these are necessary to avoid hydrolysis of the contaminating metallic cations. Both the apatite–collagen complex method and a standard chemical (STD) method employing only mineral solutions lead to biomimetic apatites when calcium and carbonate ions are introduced simultaneously. The obtained materials were fully characterized and we established that the STD method tolerates the presence of carbonate ions much better, and this leads to homogeneous samples. Emphasis was set on the repeatability of the method to ensure the relevancy of further work performed on series of samples. Finally, osteoblasts cultured on these samples also proved a similar yield and standard-deviation in their adenosine triphosphate content when compared to commercially available substrates designed to study of such cell cultures. (paper)

  1. Interstitial Oxide Ion Distribution and Transport Mechanism in Aluminum-Doped Neodymium Silicate Apatite Electrolytes.

    Science.gov (United States)

    An, Tao; Baikie, Tom; Orera, Alodia; Piltz, Ross O; Meven, Martin; Slater, Peter R; Wei, Jun; Sanjuán, María L; White, T J

    2016-04-01

    Rare earth silicate apatites are one-dimensional channel structures that show potential as electrolytes for solid oxide fuel cells (SOFC) due to their high ionic conductivity at intermediate temperatures (500-700 °C). This advantageous property can be attributed to the presence of both interstitial oxygen and cation vacancies, that create diffusion paths which computational studies suggest are less tortuous and have lower activation energies for migration than in stoichiometric compounds. In this work, neutron diffraction of Nd(28+x)/3AlxSi6-xO26 (0 ≤ x ≤ 1.5) single crystals identified the locations of oxygen interstitials, and allowed the deduction of a dual-path conduction mechanism that is a natural extension of the single-path sinusoidal channel trajectory arrived at through computation. This discovery provides the most thorough understanding of the O(2-) transport mechanism along the channels to date, clarifies the mode of interchannel motion, and presents a complete picture of O(2-) percolation through apatite. Previously reported crystallographic and conductivity measurements are re-examined in the light of these new findings. PMID:27015162

  2. Mechanism and Kinetics for the Dissolution of Apatitic Materials in Acid Solutions

    Directory of Open Access Journals (Sweden)

    Calmanovici C.E.

    1997-01-01

    Full Text Available Abstract - This work concerns the study of the digestion step in the production process of phosphoric acid. Some qualitative experiments indicate that the difference between the pH at the surface of the phosphate and that in the bulk of the solution is negligible and that the dissolution is controlled by diffusion of products away from the phosphate particle. In further experiments, to isolate the dissolution phenomenon from the formation of calcium sulfate, the sulfuric acid normally used industrially is replaced by hydrochloric acid. The phosphate material used in our experiments is a model apatitic material: synthetic hydroxyapatite (HAP. The dissolution of calcium hydroxyapatite was studied with increasing amounts of calcium and phosphate at different temperatures. A simple method was developed for this observation based on the time required for complete dissolution of the HAP powder. The results confirm that the dissolution is controlled by a diffusional process through an interface of calcium and phosphate ions released from the solid surface. A kinetic model for the dissolution of apatitic materials is proposed which assumes a shrinking particle behaviour controlled by diffusion of calcium ions. The experimental results are fitted to this model to determine the mass transfer constant for HAP dissolution in acid solutions. The activation energy of the reaction is about 14kJ/mol. This study was carried on in conditions similar to the industrial ones for the production of phosphoric acid by the dihydrate-process

  3. Electrodeposited apatite coating for solid-phase microextraction and sensitive indirect voltammetric determination of fluoride ions.

    Science.gov (United States)

    Mao, Yuehong; Chen, Yufei; Chu, Lin; Zhang, Xiaoli

    2013-10-15

    Electrodeposition was used to prepare a new solid phase microextraction (SPME) coatings. Two apatite SPME coatings, dicalcium phosphate dihydrate (DCPD or brushite) and hydroxyapatite (HAP) were validly and homogeneously one-step electrodeposited on glassy carbon electrode (GCE) under different conditions. The coatings were characterized by XRD, FTIR, SEM, CV and EIS. The apatite SPME coatings showed excellent and selective adsorbability to fluoride ions. A novel indirect voltammetric strategy for sensitive detection of fluoride was proposed using K3Fe(CN)6 as indicating probe. The detection principle of fluoride ions was based on the increment of steric hindrance after fluoride adsorption, which resulting in the decrease of the amperometric signal to Fe(CN)6(3-). The liner ranges were 0.5-20.0 μmol/L for n-DCPD/GCE with the limit of detection of 0.14 μmol/L and 0.1-50.0 μmol/L for n-HAP/GCE with the limit of detection of 0.069 μmol/L, respectively. The developed method was applied to the analysis of water samples (lake, spring and tap water) and the recovery values were found to be in the range of 90-106%. PMID:24054624

  4. Sorption behavior of Zn(II) ions on synthetic apatitic calcium phosphates

    Science.gov (United States)

    Sebei, Haroun; Pham Minh, Doan; Nzihou, Ange; Sharrock, Patrick

    2015-12-01

    The synthesis, characterization and the reactivity of apatitic calcium phosphates (Ca-HA, chemical formula Ca10(PO4)6(OH)2) is reported. Calcium carbonate (CaCO3) and potassium dihydrogen orthophosphate (KH2PO4) were selected as economical starting materials for the synthesis of Ca-HA under atmospheric conditions. Monocalcium phosphate monohydrate (MCPM), dicalcium phosphate dihydrate (DCPD), and octacalcium phosphate pentahydrate (OCP) were identified as the main intermediates of the synthesis reaction. The product obtained after 48 h of reaction contains mainly low-crystalline Ca-HA and small amounts of other calcium phosphates such as octacalcium phosphate (OCP), B-type carbonate apatite (CAP), as well as unreacted calcium carbonate. This Ca-HA was found to be active for the removal of Zn2+ from an aqueous solution. Its sorption capacity reached up to 120 mg of Zn2+ per g of Ca-HA powder after 24 h of reaction. The monitoring of soluble Zn, Ca and P during the sorption experiment allowed characterizing the mechanism of Zn uptake. Dissolution-precipitation, ionic exchange and surface complexation are the three main mechanisms involved in the sorption processes. The contribution of these mechanisms is discussed in detail.

  5. Apatite weathering as a geological driver of high uranium concentrations in groundwater

    International Nuclear Information System (INIS)

    Highlights: • High groundwater U concentrations occur in a Triassic aquifer of northern Bavaria. • U is hosted by carbonate fluorapatite phases (francolite) in aquifer inclusions. • Distribution of uraniferous facies is congruent with spatial groundwater U pattern. • Carbonate substitution and α-recoil damage from U decay enhance mineral solubility. • Mobilization of U to groundwater occurs during francolite weathering. - Abstract: Uranium is a heavy metal with potential adverse human health effects when consumed via drinking water. Although associated quality regulations have been implemented, geological sources and hydrogeochemical behavior of uranium in groundwater used for drinking water supply remain little understood. This study presents a hydrogeochemical and mineralogical characterization of a Triassic sandstone aquifer on a macro- and micro-scale, and an evaluation of uranium remobilization into groundwater, also considering the paleoenvironment and the distribution of the affected aquifer itself. Syndiagenetic uraniferous carbonate fluorapatite inclusions within the aquifer sandstones (“active arkoses”) were found to show structurally (chemical substitution in the crystal structure) and radiatively (α-recoil damage from uranium decay) enhanced mineral solubility. Extraction experiments indicated that these inclusions release uranium to groundwater during weathering. In conclusion, apatite alteration was identified as the responsible mechanism for widespread groundwater uranium concentrations >10 μg L−1 in the region representing Germany’s most significant problem area in this respect. Therefore, results indicate that the studied sedimentary apatite deposits cause the regional geogenic groundwater uranium problem, and must be considered as potential uranium sources in comparable areas worldwide

  6. Highly porous polymer-derived wollastonite-hydroxycarbonate apatite ceramics for bone regeneration.

    Science.gov (United States)

    Fiocco, L; Li, S; Bernardo, E; Stevens, M M; Jones, J R

    2016-01-01

    A novel strategy was employed to synthesize highly porous wollastonite-hydroxycarbonate apatite ceramic scaffolds for bone regeneration. A commercial liquid preceramic polymer filled with micro-CaCO3 powders was foamed at low temperature (at 350 °C), using the decomposition of a hydrazine additive, and then converted into ceramic by a treatment at 700 °C. Hydroxycarbonate apatite was later developed by a phosphatization treatment of ceramized foams, in a P-rich solution, while wollastonite was obtained by a second firing, at 900 °C. The effectiveness of the method was proven by x-ray diffraction analysis, showing the presence of the two expected crystalline phases. Porosity, interconnect size distribution and mechanical strength were in the range that is thought to be suitable for bone regeneration in non-load bearing sites (compressive strength  ≈3 MPa, porosity  ≈90%, modal interconnect diameter  ≈130-160 μm). In addition, bioactivity and ion release rate were assessed in simulated body fluid (SBF). MC3T3 osteoblast precursor cells were able to colonize the material in vitro through the pore architecture and expressed osteogenic markers. PMID:27066770

  7. [Study on a new type of apatite/wollastonite porous bioactive glass-ceramic].

    Science.gov (United States)

    Yang, Weizhong; Zhou, Dali; Yin, Guangfu; Chen, Huaiqing; Xiao, Bin; Zhang, Yun

    2004-12-01

    A novel glass-ceramic has been derived from sol-gel process. In this study XRD and FTIR analysis confirmed that the main crystalline phases of the material were hydroxyapatite/fluoroapatite [Ca10(PO4)6(OH,F)] and beta-wollastonite[beta-CaSiO3]; SEM examination showed that the microstructure contained many micro pores of 2-3 microm. After pore-forming, the material possessed good macro porous structure: the size of macro pores was 300-400 microm in diameter, and pores interconnected each other. Bioactivity of the material was preliminarily evaluated in the simulate body fluid. SEM observation revealed that a lot of apatite granules had been formed on the surface of the material after soaking within 7 days. Result shows that the novel sol-gel derived apatite-wollastonite-containing glass-ceramic has good bioactivity. Porous materials have suitable microstructure as well as macrostructure, which make it an excellent material to be used as bone-repairing materials and bone tissue engineering carrier materials. PMID:15646331

  8. Preparation and biocompatibility evaluation of apatite/wollastonite-derived porous bioactive glass ceramic scaffolds

    International Nuclear Information System (INIS)

    An apatite/wollastonite-derived (A/W) porous glass ceramic scaffold with highly interconnected pores was successfully fabricated by adding a plastic porosifier. The morphology, porosity and mechanical strength were characterized. The results showed that the glass ceramic scaffold with controllable pore size and porosity displayed open macropores. In addition, good in vitro bioactivity was found for the scaffold obtained by soaking it in simulated body fluid. Mesenchymal stem cells (MSCs) were cultured, expanded and seeded on the scaffold, and the adhesion and proliferation of MSCs were determined using MTT assay and environmental scanning electron microscopy (ESEM). The results revealed that the scaffold was biocompatible and had no negative effects on the MSCs in vitro. The in vivo biocompatibility and osteogenicity were investigated by implanting both the pure scaffold and the MSC/scaffold construct in rabbit mandibles and studying histologically. The results showed that the glass ceramic scaffold exhibited good biocompatibility and osteoconductivity. Moreover, the introduction of MSCs into the scaffold observably improved the efficiency of new bone formation, especially at the initial stage after implantation. However, the glass ceramic scaffold showed the same good biocompatibility and osteogenicity as the hybrid one at the later stage. These results indicate that porous bioactive scaffolds based on the original apatite-wollastonite glass ceramic fulfil the basic requirements of a bone tissue engineering scaffold.

  9. Effect of Artificial Saliva on the Apatite Structure of Eroded Enamel

    International Nuclear Information System (INIS)

    Citric acid-induced changes in the structure of the mineral component of enamel stored in artificial saliva were studied by attenuated total reflectance infrared spectroscopy as well as complementary electron probe microanalysis and scanning electron microscopy. The results indicate that the application of artificial saliva for several hours (the minimum time period proved is 4 h) leads to slight, partial recovering of the local structure of eroded enamel apatite. However, artificial saliva surrounding cannot stop the process of loosening and breaking of P-O-Ca atomic linkages in enamel subjected to multiple citric acid treatments. Irreversible changes in the atomic bonding within 700 nm thick enamel surface layer are observed after three times exposure for 1 min to aqueous solution of citric acid having a ph value of 2.23, with a 24-hour interval between the individual treatments. The additional treatment with basic fluoride-containing solutions (1.0% NaF) did not demonstrate a protective effect on the enamel apatite structure per se.

  10. A first report of hydroxylated apatite as structural biomineral in Loasaceae – plants’ teeth against herbivores

    Science.gov (United States)

    Ensikat, Hans-Jürgen; Geisler, Thorsten; Weigend, Maximilian

    2016-01-01

    Biomineralization provides living organisms with various materials for the formation of resilient structures. Calcium phosphate is the main component of teeth and bones in vertebrates, whereas especially silica serves for the protection against herbivores on many plant surfaces. Functional calcium phosphate structures are well-known from the animal kingdom, but had not so far been reported from higher plants. Here, we document the occurrence of calcium phosphate biomineralization in the South-American plant group Loasaceae (rock nettle family), which have stinging trichomes similar to those of the well-known stinging nettles (Urtica). Stinging hairs and the smaller, glochidiate trichomes contained nanocrystalline hydroxylated apatite, especially in their distal portions, replacing the silica found in analogous structures of other flowering plants. This could be demonstrated by chemical, spectroscopic, and diffraction analyses. Some species of Loasaceae contained both calcium phosphate and silica in addition to calcium carbonate. The intriguing discovery of structural hydroxylated apatite in plants invites further studies, e.g., on its systematic distribution across the family, the genetic and cellular control of plant biomineralization, the properties and ultrastructure of calcium phosphate. It may prove the starting point for the development of biomimetic calcium phosphate composites based on a cellulose matrix. PMID:27194462

  11. A first report of hydroxylated apatite as structural biomineral in Loasaceae - plants' teeth against herbivores.

    Science.gov (United States)

    Ensikat, Hans-Jürgen; Geisler, Thorsten; Weigend, Maximilian

    2016-01-01

    Biomineralization provides living organisms with various materials for the formation of resilient structures. Calcium phosphate is the main component of teeth and bones in vertebrates, whereas especially silica serves for the protection against herbivores on many plant surfaces. Functional calcium phosphate structures are well-known from the animal kingdom, but had not so far been reported from higher plants. Here, we document the occurrence of calcium phosphate biomineralization in the South-American plant group Loasaceae (rock nettle family), which have stinging trichomes similar to those of the well-known stinging nettles (Urtica). Stinging hairs and the smaller, glochidiate trichomes contained nanocrystalline hydroxylated apatite, especially in their distal portions, replacing the silica found in analogous structures of other flowering plants. This could be demonstrated by chemical, spectroscopic, and diffraction analyses. Some species of Loasaceae contained both calcium phosphate and silica in addition to calcium carbonate. The intriguing discovery of structural hydroxylated apatite in plants invites further studies, e.g., on its systematic distribution across the family, the genetic and cellular control of plant biomineralization, the properties and ultrastructure of calcium phosphate. It may prove the starting point for the development of biomimetic calcium phosphate composites based on a cellulose matrix. PMID:27194462

  12. Confined fission track lengths in apatite: A diagnostic tool for thermal history analysis

    International Nuclear Information System (INIS)

    A compilation of the lengths of confined fission tracks in a wide variety of apatites from different geological environments has shown that the distribution of confined track lengths can provide unique thermal history information in the temperature range below about 1500C over times of the order of 106 to 109 years. The continuous production of tracks through time, coupled with the fact that the length of each track shrinks to a value characteristic of the maximum temperature it has experienced, gives a final length distribution which directly reflects the nature of the variation of temperature with time. Most distinctive of the myriad possible forms of the final distribution are the bimodal distributions, which give clear evidence of a two-stage history, including high and low temperature phases. The study of confined length distributions therefore offers invaluable evidence on the meaning of any fission-track age, and bears the potential of providing rigorous constraints on thermal history in the temperature regime below about 1500C. The results of this study strongly suggest that any apatite fission-track age determination should be supported by a confined track length distribution. (orig./RB)

  13. Enhancement of the ALP activity of C3H10T1/2 cells by the combination of an oxysterol and apatite

    Energy Technology Data Exchange (ETDEWEB)

    Son, Kyung Mi; Park, Hee Chul; Kim, Na Ryoung; Yang, Hyeong-Cheol [Department of Dental Biomaterials Science, Dental Research Institute, School of Dentistry, Seoul National University, Yeonkun-dong, Chongro-ku, Seoul 110-749 (Korea, Republic of); Lee, In-Seop, E-mail: yanghc@snu.ac.k [Atomic-scale Surface Science Research Center, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2010-08-01

    Biomimetic apatite coating has been used to load osteogenic biomolecules onto the surface of titanium implants. Apatite on the surface of biomaterials is thought to function as a reservoir of biomolecules as well as enhancing osteoconductivity. In this study, 20{alpha}-hydroxycholesterol (20{alpha}-HC), an osteogenic oxysterol, was used to induce differentiation of a mouse embryo fibroblast cell line (C3H10T1/2) by loading the oxysterol on biomimetically coated apatite of titanium discs. We found that the phosphatase (alkaline phosphatase (ALP)) activity of 20{alpha}-HC was significantly higher with ascorbic acid than alone, suggesting a need for ascorbic acid as a co-factor. When 20{alpha}-HC was added into the apatite coating solution, the ALP activity of the C3H10T1/2 cells did not increase on the apatite surface, even in the presence of ascorbic acid. However, ALP activity increased dramatically when 20{alpha}-HC was loaded by volatilization of EtOH from the apatite coat after dipping discs in 20{alpha}-HC-dissolved EtOH. Interestingly, ascorbic acid was not needed for this increase in ALP activity, suggesting a synergistic effect of 20{alpha}-HC and apatite. The concentration of calcium ions, a major component of apatite, affected the osteogenic effect of 20{alpha}-HC, and the increase in ALP activity was attenuated by L-type calcium channel inhibitors, verapamil and nifedipine. These results demonstrate that calcium ions released from apatite are important in the synergistic effect of 20{alpha}-HC and apatite.

  14. Ion microprobe U-Pb dating and REE analysis of apatite from kerogen-rich silica dike from North pole area, Pilbara Craton, Western Australia

    International Nuclear Information System (INIS)

    In order to provide a time constraint on the 13C-depleted kerogen formation in silica dikes that intruded 3.5 Ga greenstone from Pilbara Craton in Western Australia, we have carried out an ion microprobe U-Pb dating and rare earth element (REE) analysis of apatite from one of the dikes. Two types of apatite were identified in the dike, based on their occurrences. One is stick-shape apatites (Type 1 apatite) in secondary silica micro-veins that cut the silica dike. The other is granular apatites (Type 2 apatite) that occur in matrix of the silica dike. Occurrence in the secondary miro-veins (Type 1), non-igneous REE patterns (Type 1 and 2), chemical zoning (some of Type 1 and 2), iron sulfide within apatite (some of Type 2), and intergrowth of apatite and sulfide (some of Type 2) suggest that both types of apatite were crystallized in the silica dike. Ion microprobe U-Pb dating of Type 1 apatite did not give a well-constrained age, while Type 2 apatite yields a Tera-Wasserburg concordia intercept age of 3214 ± 140 Ma (95% confidence level, MSWD = 0.6) in a three-dimensional 238U/206Pb-207Pb/206Pb-204Pb/206Pb diagram, and a 204Pb/206Pb-207Pb/206Pb isochron age of 3191 ± 150 Ma (95% confidence level, MSWD = 0.5). It is difficult to judge whether the U-Pb and Pb-Pb age of Type 2 apatite is crystallization age or metamorphic age, since the estimated range of closure temperature of U-Pb system in the apatite and that of metamorphic temperature is partly overlapped. In either case, it can be safely concluded that the minimum age of the dike and kerogen is 3.2 Ga. These ages might allow the interpretation that the kerogen was produced by biological carbon fixation and/or abiological reaction at least before 3.2 Ga. (author)

  15. Thermal History of Drummond Basin, Queensland (Australia) from Apatite and Zircon (U-Th)/He Thermochronology

    Science.gov (United States)

    Zhang, W.; Min, K. K.; Bryan, S. E.

    2014-12-01

    The thermal history of the Drummond Basin in central Queensland (Australia) has only been partly investigated. Inverse thermal modeling of apatite and zircon (U-Th)/He data can reveal the complex thermal history of sedimentary basins. We performed (U-Th)/He dating for detrital apatite and zircon grains extracted from five sandstone samples from the Campaspe DDH-1 drill hole. Mean apatite helium ages generally increase from 65.9 Ma (depth = 538 m) to 83.8 Ma (depth = 263 m). The deeper four samples yielded mean zircon helium (ZHe) ages of 289.7 - 278.2 Ma, with a systematic increase of the ZHe ages from deep to shallow samples. The shallowest sample (depth = 117 m) yielded a mean ZHe age of 263.6 Ma. Our inverse thermal modeling suggests five thermal events since burial: (1) rapid heating to the maximum temperature of 180~380 oC during ~320-290 Ma, (2) rapid cooling from ~260 oC to ~80 oC during ~290-240 Ma, (3) subdued cooling from ~80 oC to ~30 oC during ~240-200 Ma, (4) slow heating from ~30 oC to ~80 oC during ~200-80 Ma, followed by (5) rapid cooling from ~80 oC to ~35 oC at ~80 Ma. The timing and temperature conditions of the initial thermal event are consistent with K/Ar ages and temperatures deduced from illite. This period was characterized by voluminous regional magmatism and crustal extension preceding opening of the overlying Bowen Basin. Rapid cooling during ~290-240 Ma identified by our inverse thermal modeling roughly coincides with the thermal relaxation phase and foreland basin phase of the overlying Bowen Basin. This rapid cooling was probably a result of cessation of extension and subsequent contractional events to the east of Bowen Basin. Cooling slowed down during ~240-200 Ma. The Drummond Basin probably underwent serious erosion during this period, coeval with the peneplanation phase of the Bowen Basin. As is delineated by our modeling, the Drummond Basin was slowly heated from ~20 oC to ~90 oC during ~200-80 Ma, synchronous with development of

  16. Microchemical and structural regular variability of apatites in 'overbuilt' enamel and dentin of human molar teeth

    International Nuclear Information System (INIS)

    The aim of a recent paper was to recognize the chemical and structural changes in apatites, which form both the enamel and the dentin of the human tooth. The aim was achieved by scrutinizing the linear elemental profiles along the cross-sections of human molar teeth. Essentially, the task was accomplished with the application of the Electron Probe Microanalysis method and with some additional studies by Micro-Raman spectrometry. All the trends in linear profiles were strictly determined. In the enamel zone they were either increasing or decreasing curves of exponential character. The direction of the investigations was to start with the tooth surface and move towards the dentin-enamel junction (DEJ). The results of the elemental studies were more visible when the detected material was divided, in an arbitrary way, into the prevailing 'core' enamel (∼93.5% of the total mass) and the remaining 'overbuilt' enamel. The material in the 'core' enamel was fully stable, with clearly determined chemical and mechanical features. However, the case was totally different in the 'overbuilt enamel', with dynamic changes in the composition. In the 'overbuilt' layer Ca, P, Cl and F profiles present the decaying distribution curves, whereas Mg, Na, K and CO32- present the growing ones. Close to the surface of the tooth the mixture of hydroxy-, chlor- and fluor-apatite is formed, which is much more resistant than the rest of the enamel. On passing towards the DEJ, the apatite is enriched with Na, Mg and CO32-. In this location, three of six phosphate groups were substituted with carbonate groups. Simultaneously, Mg is associated with the hydroxyl groups around the hexad axis. In this way, the mechanisms of exchange reactions were established. The crystallographic structures were proposed for new phases located close to DEJ. In the dentin zone, the variability of elemental profiles looks different, with the most characteristic changes occurring in Mg and Na concentrations. Mg

  17. The Kiruna-type apatite-iron oxide system in central Sweden: geology and geochemical character

    Science.gov (United States)

    Högdahl, K.; Jonsson, E.; Nilsson, K.; Troll, V.

    2012-04-01

    The only apatite-iron oxide ores in the classic Palaeoproterozoic Bergslagen ore province, central Sweden, occur semi-continuously between Grängesberg and Idkerberget. Together, they represent the largest concentration of iron ore in this part of the Fennoscandian shield. Their mineralogy, geochemistry, geometry and host rock relations all suggest that they belong to the Kiruna-type class of deposits. The apatite-iron oxide ores in Bergslagen are hosted by 1.9 Ga variably altered, metavolcanic to meta-subvolcanic rocks ranging from rhyolitic to andesitic in composition. The region has been affected by three episodes of deformation (D1-3) and regional, greenschist to amphibolite facies metamorphism during the c. 1.9-1.8 Ga Svecokarelian orogeny. The Grängesberg deposits occur as narrow, moderately SE-dipping lenses that are concordant to S0 surfaces in the host rocks. Magnetic anomaly data indicate that they extend to a depth of at least 1.7 km. The lens geometry is mainly controlled by deformation during D2. Reverse, oblique, top-to-the NNW shear is evident in the footwall, and strain partitioning due to competence contrasts between the ore and altered host rocks resulted in flattening at competent ore lens crests, leading to asymmetrical folds with opposite vergence towards pinch areas where prolate strain prevailed. D1 is evident as a crenulated cleavage and D3 appears as gentle, large-scale open folds. Geochemical data on host rocks show a systematic enrichment in REE from the least to the most altered rocks. The ore-associated alteration assemblages and the apatite-iron oxide ore feature similar and elevated REE concentrations and profiles, suggesting a link between hydrothermal alteration and oxide ore formation. However, most ore magnetite has δ18O values between +0.3 and +3.4 ‰ (ranging from -0.4 to +4.9 ‰), consistent with fractionation of oxygen between magnetite and a felsic to intermediate magma at high temperatures (Jonsson et al. 2011). These

  18. Volatile budget of Tenerife phonolites inferred from combined haüyne-apatite mineral records

    Science.gov (United States)

    Cooper, Lauren B.; Bachmann, Olivier; Huber, Christian

    2015-04-01

    Intermediate to silicic volcanic eruptions often emit more S than predicted by petrological models -- this is called the "excess S problem." While most common minerals in these magmas are poor in volatile elements, the occurrence of large phenocrysts of S-rich haüyne (up to ~13 wt% SO3) in phonolites holds much promise for better constraining volcanic volatile budgets in differentiated alkaline magmatic systems. We have examined textural zonation patterns in haüyne separates from Tenerife (Spain), using mineral oil to enhance grain transparency. Included phases were characterized by energy dispersive spectroscopy, X-ray maps, and Raman spectroscopy. Slow growth of haüyne, inferred from zones with few inclusions, likely represents cooling-induced crystallization from S-rich melt during storage in the upper crust. By contrast, rapid growth of phenocrystic haüyne, generating "wispy" zones containing Fe-rich haüyne laths and zones rich in melt inclusions, fluid inclusions, and Fe-sulfide inclusions, may be associated with magma recharge and/or upward percolation of a low-density fluid phase (i.e., "gas sparging"). Both processes could bring new pulses of S from deep within the magmatic system. Zones containing thousands of fluid inclusions provide direct physical evidence that the melt was fluid-saturated during periods of rapid haüyne growth. Transfer of S-rich fluid should occur in all volatile-rich magmatic systems, including dacitic-rhyolitic arc systems with large S excesses, but is difficult to document in such magmas devoid of a large S-rich mineral phase like haüyne. Apatite, a mineral present in all volcanic rocks, may also contain information about S. We have observed intricate chemical zonation in backscattered electron images of apatite microphenocrysts from the same Tenerife samples. Variations in volatile and trace element concentrations between successive zones (measured via wavelength dispersive spectroscopy and laser ablation-inductively coupled

  19. Characterization of mesostasis regions in lunar basalts: Understanding late-stage melt evolution and its influence on apatite formation

    Science.gov (United States)

    Potts, Nicola J.; TartèSe, Romain; Anand, Mahesh; Westrenen, Wim; Griffiths, Alexandra A.; Barrett, Thomas J.; Franchi, Ian A.

    2016-07-01

    Recent studies geared toward understanding the volatile abundances of the lunar interior have focused on the volatile-bearing accessory mineral apatite. Translating measurements of volatile abundances in lunar apatite into the volatile inventory of the silicate melts from which they crystallized, and ultimately of the mantle source regions of lunar magmas, however, has proved more difficult than initially thought. In this contribution, we report a detailed characterization of mesostasis regions in four Apollo mare basalts (10044, 12064, 15058, and 70035) in order to ascertain the compositions of the melts from which apatite crystallized. The texture, modal mineralogy, and reconstructed bulk composition of these mesostasis regions vary greatly within and between samples. There is no clear relationship between bulk-rock basaltic composition and that of bulk-mesostasis regions, indicating that bulk-rock composition may have little influence on mesostasis compositions. The development of individual melt pockets, combined with the occurrence of silicate liquid immiscibility, exerts greater control on the composition and texture of mesostasis regions. In general, the reconstructed late-stage lunar melts have roughly andesitic to dacitic compositions with low alkali contents, displaying much higher SiO2 abundances than the bulk compositions of their host magmatic rocks. Relevant partition coefficients for apatite-melt volatile partitioning under lunar conditions should, therefore, be derived from experiments conducted using intermediate compositions instead of compositions representing mare basalts.

  20. Rate of erosion and exhumation of crystalline rocks in the Hunza Karakoram defined by apatite fission track analysis

    Czech Academy of Sciences Publication Activity Database

    Kořínková, Dagmar; Svojtka, Martin; Kalvoda, J.

    2014-01-01

    Roč. 11, č. 3 (2014), s. 235-253. ISSN 1214-9705 Institutional research plan: CEZ:AV0Z30130516 Institutional support: RVO:67985831 Keywords : apatite fission -track analysis * erosion * exhumation of rocks * Karakoram Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.389, year: 2014

  1. Characterization of the bone-like apatite precipitated on high velocity oxy-fuel (HVOF) sprayed calcium phosphate deposits.

    Science.gov (United States)

    Khor, K A; Li, H; Cheang, P

    2003-02-01

    Bone-like apatite was precipitated on the surface of thermal sprayed calcium phosphate coatings following in vitro incubation in a simulated body fluid. The coatings were initially deposited on titanium alloy substrates by the high velocity oxy-fuel (HVOF) spray technique. Structural characterization and mechanical evaluation of the precipitated apatite layer were conducted. Results showed that the precipitation rate was directly influenced by the local Ca(2+) concentration in the vicinity of the coating's surface and that preferential dissolution of certain phases was found to accelerate the precipitation of the bone-like apatite. The dense precipitates exhibited a competitive Young's modulus value of approximately 120GPa, which was obtained through nanoindentation. This compared favorably to the calcium phosphate matrix. Differences in microstructure at various locations within the layer resulted in altered Young's modulus and microhardness values. Precipitation mechanism investigation was carried out through a comparative experiment. Chemical analysis showed that the precipitation of bone-like apatite on the calcium phosphate coating was quite conceivably a partial diffusion-controlled process. PMID:12485795

  2. Determination of rare earth elements, uranium and thorium in apatite minerals by inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    Determination and distribution of 18 elements such as rare earth elements (REE), uranium and thorium in apatite minerals were examined using inductively coupled plasma-mass spectrometry. The sample solution (1 mg/ml) which were prepared with hot concentrated nitric acid were directly injected into the plasma. REE, uranium and thorium contents in the apatite were determined by a calibration curve method. However, the intensity of thorium decreased by calcium phosphate in macro-component. Therefore, thorium was separated from these calcium phosphate by solvent extraction with 0.1 mol/dm3 3-Phenyl-4-benzoyl-5-isoxazolone-DIBK system. DIBK phase was evaporated by heating, dried and ashed with concentrated nitric and perchloric acids. After allowing cooling, 0.1 mol/dm3 nitric acids was added to dissolve any precipitate. The REE, uranium and thorium content in apatite minerals from USA, China and Jordan were found to be (0.24-172), (9.69-111), (0.7-7.95) ppm, respectively. It was found that lanthanoid in apatite minerals following the Oddo and Harkins law. (author)

  3. Framework 'interstitial' oxygen in La10(GeO4)5-(GeO5)O2 apatite electrolyte

    International Nuclear Information System (INIS)

    Oxygen conduction at low temperatures in apatites make these materials potentially useful as electrolytes in solid-oxide fuel cells, but our understanding of the defect structures enabling ion migration is incomplete. While conduction along [001] channels is dominant, considerable inter-tunnel mobility has been recognized. Using neutron powder diffraction of stoichiometric 'La10(GeO4)6O3', it has been shown that this compound is more correctly described as an La10(GeO4)5-(GeO5)O2 apatite, in which high concentrations of interstitial oxygen reside within the channel walls. It is suggested that these framework interstitial O atoms provide a reservoir of ions that can migrate into the conducting channels of apatite, via a mechanism of inter-tunnel oxygen diffusion that transiently converts GeO4 tetrahedra to GeO5 distorted trigonal bipyramids. This structural modification is consistent with known crystal chemistry and may occur generally in oxide apatites. (orig.)

  4. Biomimetic synthesis of poly(lactic-co-glycolic acid/multi-walled carbon nanotubes/apatite composite membranes

    Directory of Open Access Journals (Sweden)

    H. L. Zhang

    2012-08-01

    Full Text Available Bioactive guided tissue regeneration (GTR membrane has had some success for periodontal therapy. In this study, poly(lactic-co-glycolic acid (PLGA/multi-walled carbon nanotubes (MWNTs composite membranes were incubated in three supersaturated calcification solutions (SCS of different pH values for 21 days to prepare a PLGA/MWNTs/apatite composite. Scanning electron microscope (SEM, X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR, energy dispersive spectroscopy (EDS, water contact angle measurement and mechanical testing were used for characterization. It was found that after 21 days incubation, apatite with low crystallite size and crystallinity was formed on the PLGA/MWNTs composite membranes. The Ca-poor carbapatite was similar in morphology and composition to that of natural bone. The size and shape of the apatite crystals immersed in three SCS were different from each other. The hydrophilicity and mechanical properties of the PLGA/MWNTs composite membranes were significantly enhanced after mineralization. This indicated that biomimetic mineralization may be an effective method to improve the biocompatibility and bone inductivity of certain materials. The PLGA/MWNTs/apatite composites may be potentially useful in GTR applications, particularly as GTR membranes for periodontal tissue regeneration.

  5. The design and features of apatite-coated chitosan microspheres as injectable scaffold for bone tissue engineering

    International Nuclear Information System (INIS)

    In this paper we developed two types of chitosan-based microspheres with and without biomimetic apatite coatings and compared their potential as injectable scaffolds for bone regeneration. The microspheres were obtained by emulsion cross-linking (E0) and coacervate precipitation (C0), respectively. They were then biomimetically coated with apatite to become E1 and C1 microspheres. The physicochemical properties and biocompatibility of the microspheres were characterized. Both E0 and C0 microspheres presented favorable ranges of diameter, density and Rockwell hardness. However, there were differences in the degree of cross-linking, shape, morphology, degradation rate, swelling rate, pH value after PBS immersion and the biocompatibility between E0 and C0. The apatite coating was successfully prepared for both C0 and E0, which enhanced the attachment, proliferation and differentiation of MC3T3-E1 cells. In conclusion, our results suggest the feasibility of using chitosan microspheres as a potential injectable scaffold. Both the preparation method and the biomimetic apatite coating contribute to their biological properties. (paper)

  6. Apatite U-Pb thermochronolgy applied to complex geological settings - insights from geo/thermochronology and geochemistry

    Science.gov (United States)

    Paul, Andre; Spikings, Richard; Ulyanov, Alexey; Chew, David

    2016-04-01

    Application of high temperature (>350oC) thermochronology is limited to the U-Pb system of accessory minerals, such as apatite, under the assumption that radiogenic lead is lost to thermally activated volume diffusion into an infinite reservoir. Cochrane et al. (2015) have demonstrated a working example from the northern Andes of South America. Predictions from volume diffusion theory were compared with measured single grain U-Pb date correlated to shortest diffusion radius and in-situ profiles measured by LA-ICP-MS. Results from both techniques were found to be in agreement with predictions from thermally activated, volume diffusion. However, outliers from the ID-TIMS data suggested some complexity, as grains were found to be too young relative to their diffusion radius. Interaction of multiple processes can be responsible for the alteration of apatite U-Pb dates such as: (1) metamorphic (over)growth, (2) fluid aided alteration/recrystallization and (3) metamictization and fracturing of the grain. Further, predictions from volume diffusion rely on the input parameters: (a) diffusivity, (b) activation energy and (c) shortest diffusion radius. Diffusivity and activation energy are potentially influenced by the chemical composition and subsequent changes in crystal structure. Currently there is one value for diffusion parameter and activation energy established for (Durango) apatite (Cherniak et al., 1991). Correlation between diffusivity/activation energy and composition has not been established. We investigate if correlations exist between diffusivity/activation energy and composition by obtaining single grain apatite U-Pb date and chemical compostion and correlating these to their diffusion radius. We test the consistency of apatite closure temperature, by comparing the apatite U-Pb dates with lower temperature thermochronometers such as white mica and K-feldspar Ar/Ar and by petrographic observations. We test if chemical information can be a proxy to identify

  7. Genesis of rare-metal pegmatites and alkaline apatite-fluorite rocks of Burpala massi, Northern Baikal folded zone

    Science.gov (United States)

    Sotnikova, Irina; Vladykin, Nikolai

    2015-04-01

    Burpalinsky rare metal alkaline massif in the Northern Baikal folded zone in southern margin of Siberian Platform, is a of intrusion central type, created 287 Ma covering area of about 250 km2. It is composed of nepheline syenites and pulaskites grading to quartz syenites in the contacts. Veines and dykes are represented by shonkinites, sodalite syenite, leucocratic granophyres, alkali granites and numerous rare metal alkaline syenite pegmatites and two dykes of carbonatites. All rocks except for granites are cut by a large apatite-fluorite dyke rocks with mica and magnetite, which in turn is cut by alaskite granites dyke. The massif has been studied by A.M. Portnov, A.A. Ganzeev et al. (1992) Burpalinsky massif is highly enriched with trace elements, which are concentrated in pegmatite dykes. About 70 rare-metal minerals we found in massif. Zr-silicates: zircon, eudialyte, lovenite, Ti-lovenite, velerite, burpalite, seidozerite, Ca- seidozerite, Rosenbuschite, vlasovite, katapleite, Ca-katapleite, elpidite. Ti- minerals:- sphene, astrophyllite, ramsaite, Mn-neptunite bafertisite, chevkinite, Mn-ilmenite, pirofanite, Sr-perrerit, landauite, rutile, anatase, brookite; TR- minerals - loparite, metaloparite, britolite, rinkolite, melanocerite, bastnesite, parisite, ankilite, monazite, fluocerite, TR-apatite; Nb- minerals - pyrochlore, loparite. Other rare minerals leucophanite, hambergite, pyrochlore, betafite, torite, thorianite, tayniolite, brewsterite, cryolite and others. We have proposed a new scheme massif: shonkinites - nepheline syenites - alkaline syenite - quartz syenites - veined rocks: mariupolites, rare-metal pegmatites, apatite, fluorite rock alyaskite and alkaline granites and carbonatites (Sotnikova, 2009). Apatite-fluorite rocks are found in the central part of massif. This is a large vein body of 2 km length and a 20 m width cutting prevailing pulaskites. Previously, these rocks were regarded as hydrothermal low-temperature phase. New geological and

  8. Effects of UV-irradiation on in vitro apatite-forming ability of TiO2 layers

    International Nuclear Information System (INIS)

    Titanium and its alloys are employed as artificial joints, bone plates, wires, screws and bone prostheses in orthopedic and dental fields, because of their high corrosion resistance, good mechanical properties, and biocompatibility. Since they cannot directly bond to living bone-tissue through stable chemical interactions, a few surface modification techniques have been proposed for giving materials apatite-forming ability that secures bone-tissue bonding, such as chemical treatment with H2O2 or NaOH, electrochemical oxidation, electrophoretic apatite particle deposition, and UV-irradiation of surface titanium oxide layer. This study examined how the combination of H2O2 chemical treatment and UV-irradiation affected in vitro apatite-formation on TiO2 (anatase phase) layers as UV was irradiated under a few different conditions. TiO2 layer was prepared by the chemical treatment with H2O2 solution and subsequent heat-treatment (CHT). CHT samples were irradiated with UV-light for 1 h in air or in ultra-pure water. They were then soaked in Kokubo's simulated body fluid (SBF; pH 7.4) at 36.5 deg. C for 1 day. Their surface structure and morphology were examined by using a thin film X-ray diffractometer (TF-XRD), and a scanning electron microscope (SEM). The UV-irradiation of CHT in air reduced the number of active sites for apatite nucleation. On the contrary, however, the UV-irradiation in water increased them. These opposite results indicate that environmental factors of the UV-irradiation are important for controlling the in vitro apatite-forming ability of anatase layer.

  9. Effects of UV-irradiation on in vitro apatite-forming ability of TiO{sub 2} layers

    Energy Technology Data Exchange (ETDEWEB)

    Uetsuki, Keita, E-mail: dns20353@s.okayama-u.ac.jp [Graduate School of Natural Science and Technology, Okayama University, Tsushima, Kita-ku, Okayama-shi 700-8530 (Japan); Nakashima Medical Co., Ltd., Joto-Kitagata, Higashi-ku, Okayama-shi 709-0625 (Japan); Kaneda, Haruki [Faculty of Engineering, Okayama University, Tsushima, Kita-ku, Okayama-shi 700-8530 (Japan); Shirosaki, Yuki [Graduate School of Natural Science and Technology, Okayama University, Tsushima, Kita-ku, Okayama-shi 700-8530 (Japan); Hayakawa, Satoshi [Graduate School of Natural Science and Technology, Okayama University, Tsushima, Kita-ku, Okayama-shi 700-8530 (Japan); Research Center for Biomedical Engineering, Okayama University, Tsushima, Kita-ku, Okayama-shi 700-8530 (Japan); Osaka, Akiyoshi, E-mail: a-osaka@cc.okayama-u.ac.jp [Graduate School of Natural Science and Technology, Okayama University, Tsushima, Kita-ku, Okayama-shi 700-8530 (Japan); Research Center for Biomedical Engineering, Okayama University, Tsushima, Kita-ku, Okayama-shi 700-8530 (Japan)

    2010-10-15

    Titanium and its alloys are employed as artificial joints, bone plates, wires, screws and bone prostheses in orthopedic and dental fields, because of their high corrosion resistance, good mechanical properties, and biocompatibility. Since they cannot directly bond to living bone-tissue through stable chemical interactions, a few surface modification techniques have been proposed for giving materials apatite-forming ability that secures bone-tissue bonding, such as chemical treatment with H{sub 2}O{sub 2} or NaOH, electrochemical oxidation, electrophoretic apatite particle deposition, and UV-irradiation of surface titanium oxide layer. This study examined how the combination of H{sub 2}O{sub 2} chemical treatment and UV-irradiation affected in vitro apatite-formation on TiO{sub 2} (anatase phase) layers as UV was irradiated under a few different conditions. TiO{sub 2} layer was prepared by the chemical treatment with H{sub 2}O{sub 2} solution and subsequent heat-treatment (CHT). CHT samples were irradiated with UV-light for 1 h in air or in ultra-pure water. They were then soaked in Kokubo's simulated body fluid (SBF; pH 7.4) at 36.5 deg. C for 1 day. Their surface structure and morphology were examined by using a thin film X-ray diffractometer (TF-XRD), and a scanning electron microscope (SEM). The UV-irradiation of CHT in air reduced the number of active sites for apatite nucleation. On the contrary, however, the UV-irradiation in water increased them. These opposite results indicate that environmental factors of the UV-irradiation are important for controlling the in vitro apatite-forming ability of anatase layer.

  10. Combination of Slag, Limestone and Sedimentary Apatite in Columns for Phosphorus Removal from Sludge Fish Farm Effluents

    Directory of Open Access Journals (Sweden)

    Florent Chazarenc

    2010-08-01

    Full Text Available Laboratory scale studies have repeatedly reported high P-retention in slag, a by-product of the steel manufacturing industry. Thus, it has emerged as a potential material to increase P-removal from constructed wetlands (CWs. However, several limitations were highlighted by field experiments, including the high pH of treated water and clogging. We hypothesized that the addition of sedimentary rocks to slag would preserve P-removal properties while reducing the pH of treated water. Four 2.5 L-columns were filled with 100% apatite (column A; a 50% weight each mixture of limestone with apatite (column B; 10% steel slag located at the inlet, plus 45% limestone mixed with 45% apatite (column C; and a mixture of steel slag (10%, limestone (45% apatite (45% (column D. A synthetic effluent (26 mg P/L and a reconstituted sludge fish farm effluent containing 97 mg/L total suspended solids (TSS, 220 mg/L chemical oxygen demand (COD and 23.5 mg P/L phosphorus (P were applied sequentially during 373 and 176 days, under saturated flow conditions and 12–24 hours hydraulic residence time (HRT, respectively. Treatment performance, P-removal, pH and calcium (Ca2+ were monitored. Results indicated that columns that contained 10% weight steel slag resulted in a higher P retention capacity than the columns without steel slag. The highest P removal was achieved in column C, containing a layer of slag in the inlet zone, 45% apatite and 45% limestone. Feeding the columns with a reconstituted fish farm effluent led to biofilm development, but this had little effect on the P-removal. A combination of slag and sedimentary rocks represents a promising filtration material that could be useful downstream of CWs to further increase P-removal.

  11. Effects of added ZnTCP on mechanical and biological properties of apatite cement

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, K.; Suzuki, K. [Okayama Univ. Dental School (Japan). Dept. of Biomaterials; Miyamoto, Y.; Toh, T.; Yuasa, T.; Nagayama, M. [Tokushima Univ. (Japan). First Dept. of Oral and Maxillofacial Surgery; Ito, A. [National Inst. for Advanced Interdisciplinary Research, MITT, Ibaragi (Japan)

    2001-07-01

    Effects of added Zn doped {beta}-tricalcium phosphate (ZnTCP) on mechanical and biological properties of apatite cement (AC) was studied. Powder X-ray diffractometer revealed that ZnTCP shows no reactivity with AC. The mechanical strength of AC decreased increasing amounts of added ZnTCP. We observed no effect on the setting time of AC when the amount of ZnTCP was 10% or less. Proliferation of the osteoblastic cells was significantly increased on the surface of AC containing 5% ZnTCP when compared with that containing no ZnTCP. In contrast, proliferation of the cells decreased on the surface of AC containing 10% ZnTCP when compared with that free from ZnTCP; indicating cytotoxity. We concluded therefore, that addition of ZnTCP to AC might be useful to enhance the osteoconductivity of AC when release of Zn{sup 2+} can be carefully regulated. (orig.)

  12. Experimental osteoinduction in rats: collagen-apatite versus osteogenin-containing gelatine.

    Science.gov (United States)

    Schwarz, N; Redl, H; Schlag, G; Lintner, F; Dinges, H P; Thurnher, M; Schiesser, A

    1987-01-01

    An experimental study in rats was done to investigate the bone-regenerating properties of collagen apatite (Collapat) and to compare it with osteoinduction dependent on osteogenin-containing gelatine (OCG). The test substances were implanted orthotopically (calvarial defect--7 mm in diameter) and heterotopically (paravertebral muscles, abdominal muscles). The results were evaluated histologically and enzymatically (alkaline phosphatase). Collapat caused neither osteoinduction in the heterotopic site nor healing of the bone defects. Foreign body reaction without new bone formation was encountered. OCG implantation leads to new bone formation in the muscles within 3 weeks, associated with a significant increase in alkaline phosphatase activity, and to extensive new bone formation in the calvarial defect within 4 weeks. The defects did not heal if left empty. The value of clinical application of Collapat appears to be doubtful. Osteoinduction with OCG requires further experimental investigation. PMID:3551878

  13. Study of cation-localisation in apatite and orthophosphate structures using 181Hf/181Ta probe

    International Nuclear Information System (INIS)

    Nuclear quadrupole interaction study using Time Differential Perturbed Angular Correlation technique has been carried out to identify the sites where hafnium can reside in hydroxyapatite in order to mimic the behavior of plutonium adsorption on hydroxyapatite. Hf(IV) has been found to occupy three sites with the quadrupole interaction frequency (ωQ) and its asymmetry (η): (i) ωQ = 136.7(5) Mrad/s, η = 0.54(1); (ii) ωQ 300.1(9) Mrad/s, η = 0.35(2); (iii) ωQ = 124.6(5), η = 0.0(1). Narrow frequency distributions indicate the sites are well-defined. This study has been extended to barium orthophosphate to confirm our inference for the apatite structure. (author)

  14. The influence of parameters of A-type carbonated apatites synthesis on radiation dose response

    International Nuclear Information System (INIS)

    The aim of this work is the investigation of dose response of A-type carbonated apatites prepared in different conditions. Irradiated samples prepared with carbonate content of 1.45 to 4.84% are studied by using electron paramagnetic resonance (EPR). The EPR spectra are mainly constituted of lines associated to axial CO2- species (gperp = 2.0028 and g// = 1.9973) and CO3- species (g1 = 2,0170, g2 = 2,0090 e g3 = 2,0041). The production of CO2- species on gamma irradiation depends on the carbonate concentration and the hydroxyapatite stoichiometry. The lowest dose detection limit was achieved with stoichiometric samples and carbonate content around of 3.7%. (author)

  15. Porous apatite-wollastonite glass-ceramic as an intramedullary plug.

    Science.gov (United States)

    Fujita, H; Iida, H; Ido, K; Matsuda, Y; Oka, M; Nakamura, T

    2000-05-01

    We evaluated the efficacy and biocompatibility of porous apatite-wollastonite glass ceramic (AW-GC) as an intramedullary plug in total hip replacement (THR) for up to two years in 22 adult beagle dogs. Cylindrical porous AW-GC rods (70% porosity, mean pore size 200 microm) were prepared. Four dogs were killed at 1, 3, 6 and 12 months each and six at 24 months after implantation. Radiological evaluation confirmed the efficacy of porous AW-CG as an intramedullary plug. Histological evaluation showed osteoconduction at one month and resorption of the porous AW-GC, which was replaced by newly-formed bone, at 24 months. Our findings indicate that porous AW-GC can be used clinically as an intramedullary plug in THR. PMID:10855893

  16. Indirect selective laser sintering of apatite-wollostonite glass-ceramic.

    Science.gov (United States)

    Xiao, K; Dalgarno, K W; Wood, D J; Goodridge, R D; Ohtsuki, C

    2008-10-01

    This paper develops an indirect selective laser sintering (SLS) processing route for apatite-wollastonite (A-W) glass-ceramic, and shows that the processing route, which can create porous three-dimensional products suitable for bone implants or scaffolds, does not affect the excellent mechanical and biological properties of the glass-ceramic. 'Green parts' with fine integrity and well-defined shape have been produced from glass particles of single-size range or mixed-size ranges with acrylic binder in various ratios by weight. A subsequent heat treatment process has been developed to optimize the crystallization process, and an infiltration process has been explored to enhance mechanical strength. Three-point bending test results show flexural strengths of up to 102 MPa, dependent on porosity, and simulated body fluid (SBF) tests show that the laser sintered porous A-W has comparable biological properties to that of conventionally produced A-W. PMID:19024158

  17. Mesozoic-Cenozoic thermal history of Turpan-Hami Basin: apatite fission track constraints

    Institute of Scientific and Technical Information of China (English)

    ZHU Wenbin; WAN Jinglin; SHU Liangshu; SUN Yan; GUO Jichun; WANG Feng

    2005-01-01

    Apatite fission track dating is carried out on nine samples collected from the central part (Lianmuqin section) and from both northern and southern margins of Turpan-Hami Basin. The fission-track ages of seven Jurassic samples are distinctly younger than depositional ages. In contrast, the fission-track ages of two Cretaceous samples are older than, or as old as depositional ages. These observations indicate that the Jurassic samples have been annealed or partially annealed, whereas the Cretaceous samples have not been annealed.The further thermal modelling results show that Turpan-Hami Basin experienced a Late Cretaceous period (120-100 Ma) of tectonic uplift with rapid cooling and exhumation of sediments. The samples underwent a Cenozoic period of reburial and re-heating and were exhumed again at 10-8 Ma.

  18. Thermal conductivity of the gadolinium calcium silicate apatites: Effect of different point defect types

    International Nuclear Information System (INIS)

    The apatite crystal structure of the gadolinium calcium silicates can accommodate a wide range of point defects, including oxygen and cation vacancies, as well as anti-site defects, depending on the Gd/Ca ratio. Compositions having only cation or oxygen vacancies were identified and the thermal diffusivity and conductivity were measured up to 1000 deg. C. All the compositions, including the stoichiometric composition, exhibit low thermal conductivities from room temperature to high temperature with the defect-containing compositions having even lower thermal conductivities. The high-temperature thermal conductivity, at temperatures below the onset of significant radiative heat transport, decreases with the inverse square root of the cation and anion vacancy concentration, consistent with simple defect scattering models. Based on the data, it is concluded that the oxygen vacancies are slightly more effective in reducing thermal conductivity.

  19. Strong correlation in 1D oxygen-ion conduction of apatite-type lanthanum silicate

    International Nuclear Information System (INIS)

    Oxygen-ion conduction in apatite-type lanthanum silicate, La9.33+0.67x(SiO4)6O2+x (x = 1), has theoretically been analyzed in a first-principles manner followed by the nudged elastic band method and the kinetic Monte Carlo method. Unlike the conventional cooperative interstitialcy mechanism along the single O4 columns, diffusing interstitial oxygen ions are frequently blocked by adjacent interstitial oxygen ions (Oint ions), leading to the strongly-correlated diffusivity and conductivity of oxygen ions in the case of chemical compositions with large x values. The getting-out mechanism from the O4 column is of importance in the long-range conduction, which temporarily transfers a part of Oint ions out of the columns to relax the blocking effect. The getting-out mechanism plays a key role also in the conduction perpendicular to the c axis (in the ab plane). (paper)

  20. On-stream analysis, by x-ray diffraction, of apatite-containing slurries

    International Nuclear Information System (INIS)

    The paper describes the equipment and method developed for the on-stream analysis of apatite in the slurries of a beneficiation plant. The equipment uses a divergent beam of X-rays that irradiates the slurry as it flows through a sample presenter. The diffracted beam is focused by an elastically bent quartz monochromator crystal into a scintillation detector. The P2O5 content and percentage solids in the slurry are determined from peak and background intensities by the use of a quadratic equation. Measurements showed that the accuracy of these determinations is comparable with that of chemical analysis, which is the method used at present. In addition, one analysis takes two minutes as against the 20 minutes required for each chemical analysis

  1. Interface characterization of plasma sprayed hydroxy apatite coat on Ti-6 Al-4 V

    International Nuclear Information System (INIS)

    Hydroxyapatite, a material proven to be biocompatible within the human body, has been produced to a high level of purity. This material has been applied as a coating on Ti-6 Al-4 V alloy by using the air plasma spraying technique.The coat was characterized with SEM, XRD, FTIR and Raman spectroscopy methods to consist of a mixture of calcium phosphates including H A mainly and traces of tricalcium phosphate, tetra calcium phosphate and calcium oxide phases. This H A phase was dehydrated and partially decomposed to oxy apatite and amorphous H A. EPMA method was used cross-sectionally on the interface in order to determine the depth profiles and elemental maps of Calcium, Phosphorous, Oxygen, Titanium, Vanadium and Aluminum elements.The results clearly showed to evidence of interdiffusion at the interface. Ultimately, the diffusion depth of each element was studied and compared with each other

  2. Technology of production of high-level concentrate of rare earths from Kola apatite

    International Nuclear Information System (INIS)

    The procedure is described of separating rare earth elements from the Kola apatite which contains 0.7 to 1.0% oxides of rare earths. The separation takes place during the manufacture of combined fertilizer NPK-1. During the manufacture of the fertilizer the solution is neutralized with the precipitation of phosphates of rare earths. Increasing pH is accompanied by increased yield of the sum of rare earths. The yield is higher for lighter lanthanoids than for heavier lanthanoids. The phosphate concentrate is decomposed by nitric acid and rare earth elements are precipitated by oxalic acid. Following the annealing of the oxalate concentrate the obtained oxide concentrate will contain 92 to 95% oxides of rare earths. (E.S.)

  3. Prompt isothermal decay of thermoluminescence in an apatite exhibiting strong anomalous fading

    Science.gov (United States)

    Sfampa, I. K.; Polymeris, G. S.; Tsirliganis, N. C.; Pagonis, V.; Kitis, G.

    2014-02-01

    Anomalous fading (AF) is one of the most serious drawbacks in thermoluminescence (TL) and optically stimulated luminescence (OSL) dating. In the present work the isothermal decay of TL signals from Durango apatite is studied for temperatures located on the rising part of the main TL peak. This material is known to exhibit strong AF phenomena, and its isothermal TL decay properties have not been studied previously. The experimental results show that the characteristic decay time of the isothermal signal does not depend of the temperature, and that this signal does not exhibit the strong temperature dependence expected from conventional TL kinetic theories. This is further direct experimental evidence for the possible presence of tunneling phenomena in this material. The isothermal decay curves are analyzed and discussed within the framework of conventional theories of TL, as well as within the context of a recently developed tunneling kinetic model for random distributions of electron-hole pairs in luminescent materials.

  4. Extraction and characterisation of apatite- and tricalcium phosphate-based materials from cod fish bones

    International Nuclear Information System (INIS)

    Apatite- and tricalcium phosphate-based materials were produced from codfish bones, thus converting a waste by-product from the food industry into high added-valued compounds. The bones were annealed at temperatures between 900 and 1200 °C, giving a biphasic material of hydroxyapatite and tricalcium phosphate (Ca10(PO4)6(OH)2 and β-Ca(PO4)3) with a molar proportion of 75:25, a material widely used in biomedical implants. The treatment of the bones in solution prior to their annealing changed the composition of the material. Single phase hydroxyapatite, chlorapatite (Ca10(PO4)6Cl2) and fluorapatite (Ca10(PO4)6F2) were obtained using CaCl2 and NaF solutions, respectively. The samples were analysed by several techniques (X-ray diffraction, infrared spectroscopy, scanning electron microscopy and differential thermal/thermogravimetric analysis) and by elemental analyses, to have a more complete understanding of the conversion process. Such compositional modifications have never been performed before for these materials of natural origin to tailor the relative concentrations of elements. This paper shows the great potential for the conversion of this by-product into highly valuable compounds for biomedical applications, using a simple and effective valorisation process. - Highlights: ► Apatite and calcium phosphate compounds extraction from cod fish bones ► Bone calcination: biphasic material hydroxyapatite-calcium phosphate production ► Bone pre-treatments in solution change the material composition. ► Single phase materials (hydroxy-, chloro- or fluoroapatite) are obtained. ► Concentration of other elements (Na, F, Cl) suitable for biomedical applications

  5. Ectopic bone induction in porous apatite-wollastonite-containing glass ceramic combined with bone morphogenetic protein.

    Science.gov (United States)

    Ijiri, S; Nakamura, T; Fujisawa, Y; Hazama, M; Komatsudani, S

    1997-06-15

    To accelerate the integration of ceramic implants with the surrounding bone and to search for a suitable carrier for bone morphogenetic protein (BMP), we studied ectopic bone induction in porous apatite-wollastonite-containing glass ceramic (A-W GC) combined with partially purified bovine BMP (bBMP) and recombinant Xenopus BMP-4/7 (rxBMP-4/7). Porous A-W GC rods [4 mm in diameter, 5 mm in height, 70% porosity, 200 microns mean pore size, 17.54 +/- 3.82 MPa (mean +/- SD) compressive strength] were used. An apatite coating formed on the surface of porous A-W GC that had been immersed in simulated body fluid at 36.5 degrees C for 7 days. In experiment 1, porous A-W GC rods were combined with either bBMP, collagen, or with both bBMP and collagen. The rods were implanted into subcutaneous pouches in rats and were harvested 4 weeks after implantation. Low-energy radiographic, scanning electron microscopic (SEM), and histological examinations showed ectopic bone formation and within the rods only in the porous A-W GC combined with the bBMP and collagen group. Quantitative analysis also revealed that this group alone showed a significant increase in bone formation. In experiment 2, porous A-W GC rods were combined with rxBMP and collagen, implanted into rats, and harvested as described above. SEM and histological examination showed ectopic bone formation around and within the rods. Because of its relatively high mechanical strength, ease of handling, and good osteoinductivity, porous A-W GC combined with BMP and collagen may be clinically useful in patients with large cancellous bone defects or craniomaxillofacial lesions. PMID:9189820

  6. Ion microprobe U-Pb dating and REE abundance of biogenic apatite

    Science.gov (United States)

    Sano, Y.; Terada, K.; Ueki, S.

    2001-12-01

    If the direct U-Pb dating of a fossil itself is possible, the method could have great impact on stratigraphic studies in establishing the absolute chronology of sedimentary sequences. Micro fossil ?conodont? are candidates for this purpose since they consist of apatite (Ca2(PO5)3 (F,Cl,OH)), which would uptake U, Th and Pb after sedimentation no longer than a few million years and is supposed to remain closed to U and Pb under relatively low effective closure temperature. We report here results of direct ion microprobe U-Th-Pb dating of two conodonts; Trichognathus from Kinderhookian stage of Mississippian sedimentary sequence from Illinois Basin region in North America and Panderodus from a Llandoverian sedimentary sequence on Langkawi Island, northern Malaysia. Secondary purpose of the study is to indicate in situ analysis of all REE on the same spots of U-Pb measurements. Samples were cast into epoxy resin discs with a few grains of standard apatite, PRAP, derived from an alkaline rock of Prairie Lake circular complex in the Canadian Shield and polished until they were exposed through their mid-sections. U, Th and REE abundances, and Pb isotopic compositions were measured by using SHRIMP installed at Hiroshima University. Thirteen spots on Trichognathus yield a 238U/206Pb isochron age of 323+/-36 Ma, which is consistent with the depositional and early diagenetic ages. Fifteen spots on Panderodus give 232Th/208Pb isochron age of 429+/-50 Ma, which is again comparable to an early Silurian. Shale-normalized REE of Trichognathus shows a broadly flat pattern from light to middle REE and a decrease from middle to heavy REE with negative anomalies of Ce and Eu. In contrast Panderodus indicates a concave-shape pattern with middle REE enrichment. These characteristics are probably due to a different formation environment as suggested by other workers.

  7. Nanomedicine: Interaction of biomimetic apatite colloidal nanoparticles with human blood components.

    Science.gov (United States)

    Choimet, Maëla; Hyoung-Mi, Kim; Jae-Min, Oh; Tourrette, Audrey; Drouet, Christophe

    2016-09-01

    This contribution investigates the interaction of two types of biomimetic-apatite colloidal nanoparticles (negatively-charged 47nm, and positively-charged 190nm NPs) with blood components, namely red blood cells (RBC) and plasma proteins, with the view to inspect their hemocompatibility. The NPs, preliminarily characterized by XRD, FTIR and DLS, showed low hemolysis ratio (typically lower than 5%) illustrating the high compatibility of such NPs with respect to RBC, even at high concentration (up to 10mg/ml). The presence of glucose as water-soluble matrix for freeze-dried and re-dispersed colloids led to slightly increased hemolysis as compared to glucose-free formulations. NPs/plasma protein interaction was then followed, via non-specific protein fluorescence quenching assays, by contact with whole human blood plasma. The amount of plasma proteins in interaction with the NPs was evaluated experimentally, and the data were fitted with the Hill plot and Stern-Volmer models. In all cases, binding constants of the order of 10(1)-10(2) were found. These values, significantly lower than those reported for other types of nanoparticles or molecular interactions, illustrate the fairly inert character of these colloidal NPs with respect to plasma proteins, which is desirable for circulating injectable suspensions. Results were discussed in relation with particle surface charge and mean particle hydrodynamic diameter (HD). On the basis of these hemocompatibility data, this study significantly complements previous results relative to the development and nontoxicity of biomimetic-apatite-based colloids stabilized by non-drug biocompatible organic molecules, intended for use in nanomedicine. PMID:27137807

  8. Extraction and characterisation of apatite- and tricalcium phosphate-based materials from cod fish bones

    Energy Technology Data Exchange (ETDEWEB)

    Piccirillo, C.; Silva, M.F. [CBQF/Escola Superior de Biotecnologia, Universidade Catolica Portuguesa, Porto (Portugal); Pullar, R.C. [Dept. Engenharia de Materiais e Ceramica/CICECO, Universidade de Aveiro, Aveiro (Portugal); Braga da Cruz, I. [CBQF/Escola Superior de Biotecnologia, Universidade Catolica Portuguesa, Porto (Portugal); WeDoTech, CiDEB/Escola Superior de Biotecnologia, Universidade Catolica Portuguesa, Porto (Portugal); Jorge, R. [WeDoTech, CiDEB/Escola Superior de Biotecnologia, Universidade Catolica Portuguesa, Porto (Portugal); Pintado, M.M.E. [CBQF/Escola Superior de Biotecnologia, Universidade Catolica Portuguesa, Porto (Portugal); Castro, P.M.L., E-mail: plcastro@porto.ucp.pt [CBQF/Escola Superior de Biotecnologia, Universidade Catolica Portuguesa, Porto (Portugal)

    2013-01-01

    Apatite- and tricalcium phosphate-based materials were produced from codfish bones, thus converting a waste by-product from the food industry into high added-valued compounds. The bones were annealed at temperatures between 900 and 1200 Degree-Sign C, giving a biphasic material of hydroxyapatite and tricalcium phosphate (Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2} and {beta}-Ca(PO{sub 4}){sub 3}) with a molar proportion of 75:25, a material widely used in biomedical implants. The treatment of the bones in solution prior to their annealing changed the composition of the material. Single phase hydroxyapatite, chlorapatite (Ca{sub 10}(PO{sub 4}){sub 6}Cl{sub 2}) and fluorapatite (Ca{sub 10}(PO{sub 4}){sub 6}F{sub 2}) were obtained using CaCl{sub 2} and NaF solutions, respectively. The samples were analysed by several techniques (X-ray diffraction, infrared spectroscopy, scanning electron microscopy and differential thermal/thermogravimetric analysis) and by elemental analyses, to have a more complete understanding of the conversion process. Such compositional modifications have never been performed before for these materials of natural origin to tailor the relative concentrations of elements. This paper shows the great potential for the conversion of this by-product into highly valuable compounds for biomedical applications, using a simple and effective valorisation process. - Highlights: Black-Right-Pointing-Pointer Apatite and calcium phosphate compounds extraction from cod fish bones Black-Right-Pointing-Pointer Bone calcination: biphasic material hydroxyapatite-calcium phosphate production Black-Right-Pointing-Pointer Bone pre-treatments in solution change the material composition. Black-Right-Pointing-Pointer Single phase materials (hydroxy-, chloro- or fluoroapatite) are obtained. Black-Right-Pointing-Pointer Concentration of other elements (Na, F, Cl) suitable for biomedical applications.

  9. Synthesis of trace element bearing single crystals of Chlor-Apatite (Ca5(PO4)3Cl) using the flux growth method.

    Science.gov (United States)

    Klemme, Stephan; John, Timm; Wessels, Mathias; Kusebauch, Christof; Berndt, Jasper; Rohrbach, Arno; Schmid-Beurmann, Peter

    2013-01-01

    We present a new strategy on how to synthesize trace-element bearing (REE, Sr) chlorapatites Ca5(PO4)3Cl using the flux growth method. Synthetic apatites were up to several mm long, light blue in colour. The apatites were characterized using XRD, electron microprobe and laser ablation ICP-MS (LA-ICPMS) techniques and contained several hundred μg/g La, Ce, Pr, Sm, Gd and Lu and about 1700 μg/g Sr. The analyses indicate that apatites were homogenous (within the uncertainties) for major and trace elements. PMID:23531340

  10. Biogenic hydroxyapatite (Apatite II Trade-Mark-Sign ) dissolution kinetics and metal removal from acid mine drainage

    Energy Technology Data Exchange (ETDEWEB)

    Oliva, J. [Department of Mining Engineering and Natural Resources, Politechnical University of Catalunya, Bases de Manresa 61-73, Manresa 08242, Catalonia (Spain); Cama, J., E-mail: jordi.cama@idaea.csic.es [Department of Geosciences, Institute of Environmental Assessment and Water Research, IDAEA, CSIC, Jordi Girona 18-26, Barcelona 08034, Catalonia (Spain); Cortina, J.L. [Department of Chemical Engineering, Politechnical University of Catalunya, Avinguda Diagonal 647, Barcelona 08028, Catalonia (Spain); Ayora, C. [Department of Geosciences, Institute of Environmental Assessment and Water Research, IDAEA, CSIC, Jordi Girona 18-26, Barcelona 08034, Catalonia (Spain); De Pablo, J. [Department of Chemical Engineering, Politechnical University of Catalunya, Avinguda Diagonal 647, Barcelona 08028, Catalonia (Spain)

    2012-04-30

    Apatite II Trade-Mark-Sign is a biogenic hydroxyapatite (expressed as Ca{sub 5}(PO{sub 4})OH) derived from fish bone. Using grains of Apatite II Trade-Mark-Sign with a fraction size between 250 and 500 {mu}m, batch and flow-through experiments were carried out to (1) determine the solubility constant for the dissolution reaction Ca{sub 5}(PO{sub 4}){sub 3}(OH) Left-Right-Double-Arrow 5Ca{sup 2+} + 3PO{sub 4}{sup 3-} + OH{sup -}, (2) obtain steady-state dissolution rates over the pH range between 2.22 and 7.14, and (3) study the Apatite II Trade-Mark-Sign 's mechanisms to remove Pb{sup 2+}, Zn{sup 2+}, Mn{sup 2+}, and Cu{sup 2+} from metal polluted water as it dissolves. The log K{sub S} value obtained was -50.8 {+-} 0.82 at 25 Degree-Sign C. Far-from-equilibrium fish-bone hydroxyapatite dissolution rates decrease by increasing pH. Assuming that the dissolution reaction is controlled by fast adsorption of a proton on a specific surface site that dominates through the pH range studied, probably {identical_to}P-O{sup -}, followed by a slow hydrolysis step, the dissolution rate dependence is expressed in mol m{sup -2} s{sup -1} as Rate{sub 25 Degree-Sign C}=-8.9 Multiplication-Sign 10{sup -10} Multiplication-Sign (9.96 Multiplication-Sign 10{sup 5} Multiplication-Sign a{sub H{sup +}})/(1+9.96 Multiplication-Sign 10{sup 5} Multiplication-Sign a{sub H{sup +}}) where a{sub H{sup +}} is the proton activity in solution. Removal of Pb{sup 2+}, Zn{sup 2+}, Mn{sup 2+} and Cu{sup 2+} was by formation of phosphate-metal compounds on the Apatite II Trade-Mark-Sign substrate, whereas removal of Cd{sup 2+} was by surface adsorption. Increase in pH enhanced the removal of aqueous heavy metals. Using the kinetic parameters obtained (e.g., dissolution rate and pH-rate dependence law), reactive transport simulations reproduced the experimental variation of pH and concentrations of Ca, P and toxic divalent metal in a column experiment filled with Apatite II Trade-Mark-Sign that was

  11. Experimental study of kinetic and mechanism of dissolution of apatite structured minerals. Application to the prediction of the long term behavior of an actinides storage host matrix

    International Nuclear Information System (INIS)

    The motivation for this study is to assess the potential of using apatite structured ceramics as long-lived actinide storage hosts. To assess their ability to resist aqueous corrosion, the dissolution of natural fluoro-apatite and synthetic Nd-britholite (neodymium is a proxy for the trivalent actinides) was studied. Mineral surfaces were characterized using a combined spectrometric, electrokinetic and potentiometric approach and dissolution rates were measured in closed and open system reactors as a function of solution composition. Experimental results suggest apatitic minerals dissolve via distinct step sequence: 1) fluoride release, 2) release of the calcium situated in the M1, and 3) the simultaneous removal of phosphate and calcium II via the breaking of only Ca-O bonds. TST based rate equations based in this mechanism accurately describe fluoro-apatite and synthetic britholite dissolution rates as a function of solution composition. Nd release rates are limited by precipitation of Nd-rhabdophane. (author)

  12. Evidence for the exsolution of Cl-rich fluids in martian magmas: Apatite petrogenesis in the enriched lherzolitic shergottite Northwest Africa 7755

    Science.gov (United States)

    Howarth, G. H.; Pernet-Fisher, J. F.; Bodnar, R. J.; Taylor, L. A.

    2015-10-01

    Martian meteorite Northwest Africa 7755 is a new example of an enriched, lherzolitic shergottite, containing some of the coarsest-grained apatite yet identified in shergottite meteorites. Their size has permitted detailed observations of volatile distributions within single grains. We have demonstrated that some apatites have been invaded by shock melts, which act to devolatilize parts of grains, resulting in significant Cl-enrichment in the adjacent regions. The extent of chemical heterogeneity within single grains must be carefully considered in other shergottites, so that the effects of secondary modification of apatites are well-constrained, prior to interpreting the volatile contents and primary magmatic processes. Apatite grains unaffected by shock melts are OH-F enriched and Cl-poor (∼F50Cl14OH36), relative to interstitial apatites reported in other shergottites. The volatile compositions are similar to interstitial apatites reported in terrestrial mafic intrusions. Such apatites in terrestrial intrusions are argued to have formed after significant Cl-loss due to the exsolution and migration of Cl-rich brines. Calculated relative F2, Cl2, and H2O fugacities for NWA 7755 apatites show a trend of degassing rather than fractionation, noted in previous studies. Indeed, we interpret the volatile contents of apatites analyzed in the cumulate shergottite NWA 7755 to represent snapshots of the evolving late-stage residual liquid during exsolution of a Cl-rich brine. This fluid phase has subsequently been lost from an open magma system, migrating upward through the cumulate sequence enriching residual liquids in Cl. Alternatively, it formed a hydrothermal system in the martian crust surrounding the intrusion. Furthermore, by comparison with terrestrial examples, we suggest that the late-stage evolution of volatile-bearing phases in NWA 7755 is similar to that of comparable terrestrial mafic rocks. Primary cumulus apatites are F-rich, whereas interstitial apatites

  13. Lu-Hf isotope systematics of fossil biogenic apatite and their effects on geochronology

    Science.gov (United States)

    Herwartz, Daniel; Münker, Carsten; Tütken, Thomas; Hoffmann, J. Elis; Wittke, Andreas; Barbier, Bruno

    2013-01-01

    Reliable methods for direct dating of biogenic apatite from pre-Pleistocene fossils are currently not available, and recent attempts using the Lu-Hf decay system yielded highly inaccurate ages for both bones and teeth. The geological processes accounting for this poor accuracy of Lu-Hf chronometry are not yet understood. Here we explore Lu-Hf systematics in fossil bones and teeth in detail, by applying five different sample digestion techniques that are tested on bones and composites of bone and sediment. Our current dataset implies that dissolution methods only slightly affect the resulting Lu-Hf ages, while clear differences between the individual digestion techniques became apparent for element concentrations. By analysing the insoluble leftovers from incomplete sample dissolution, four main reservoirs of Hf in fossil bones were identified: (1) a radiogenic end-member associated with apatite; (2) an unradiogenic end-member represented by the authigenic minerals or the embedding sediment; (3) a highly unradiogenic end-member that can be attributed to detrital zircon; and (4) a moderately soluble phase (probably a Zr(Hf)-phosphate) that yielded very low Lu/Hf but a highly radiogenic Hf isotope composition at the same time. This Zr(Hf)-phase must have been precipitated within the fossil bone sample at a late stage of burial history, thereby incorporating radiogenic 176Hf released from apatite surfaces over geological timescales. A second focus of our study is the effect of different sediment matrices and of crystal size on the preservation of pristine Lu-Hf isotope compositions in bioapatite. Because near-depositional Lu-Hf ages of phosphate fossils have previously been reported for the London Clay (England) and a calcareous marl from Tendaguru (Tanzania), we herein investigate specimens fossilised in carbonate matrices (calcareous marl from Oker, Germany; carbonate concretions from the Santana Formation, Brazil; carbonate from the Eifel, Germany) and argillaceous

  14. The Calcium Phosphate Matrix of FGF-2-Apatite Composite Layers Contributes to Their Biological Effects

    Directory of Open Access Journals (Sweden)

    Hirotaka Mutsuzaki

    2014-06-01

    Full Text Available The purpose of the present study was to fabricate fibroblast growth factor (FGF-2-apatite composite layers on titanium (Ti pins in one step at 25 °C using a supersaturated calcium phosphate (CaP solution, and to evaluate the physicochemical characteristics and biological effects of the coated Ti pins compared with coated Ti pins fabricated at 37 °C. Ti pins were immersed in a supersaturated CaP solution containing 0.5, 1.0, or 2.0 µg/mL FGF-2 at 25 °C for 24 h (25F0.5, 25F1.0, and 25F2.0 or containing 4.0 µg/mL FGF-2 at 37 °C for 48 h (37F4.0. Except for the 25F0.5, the chemical compositions and the mitogenic activity levels of FGF-2 of the composite layers formed by these two methods were similar, except for the Ca/P molar ratio, which was markedly smaller at 25 °C (1.55–1.56 ± 0.01–0.02, p = 0.0008–0.0045 than at 37 °C (1.67 ± 0.11. Thus, either the apatite was less mature or the amount of amorphous calcium phosphate was higher in the composite layer formed at 25 °C. In vivo, the pin tract infection rate by visual inspection for 37F4.0 (45% was lower than that for 25F1.0 (80%, p = 0.0213, and the rate of osteomyelitis for 37F4.0 (35% was lower than that for 25F0.5 (75%, p = 0.0341. The extraction torque for 37F4.0 (0.276 ± 0.117 Nm was higher than that for 25F0.5 (0.192 ± 0.117 Nm, p = 0.0142 and that for 25F1.0 (0.176 ± 0.133 Nm, p = 0.0079. The invasion rate of S. aureus for 37F4.0 (35% was lower than that for 25F0.5 (75%, p = 0.0110. On the whole, the FGF-2-apatite composite layer formed at 25 °C tended to be less effective at improving fixation strength in the bone-pin interface and resisting pin tract infections. These results suggest that the chemistry of the calcium phosphate matrix that embeds FGF-2, in addition to FGF-2 content and activity, has a significant impact on composite infection resistance and fixation strength.

  15. The Possibility of the Formation of Protocells and Their Structural Components on the Basis of the Apatite Matrix and Cocrystallizing Minerals

    OpenAIRE

    Kostetsky, Eduard Y.

    2005-01-01

    This paper presents the author's theory on the possibility of simultaneous hard-phase synthesis of various organic molecules from gas-phase elements on the basis of the apatite matrix and cocrystallizing minerals (carbonate-apatite, calcite, mica). These molecules and their ensembles gave rise to living systems and protocells of the pro- and eukaryotic types. Synthesis might have occurred through gradual substitution of the mineral matrix by crystal organic matter. The structure and size of t...

  16. Understanding the uplift pattern in Mesozoic and Cenozoic,, eastern Dabie area, China using fission track dating of apatite

    International Nuclear Information System (INIS)

    By using the fission track dating technique, a preliminary study was carried out on the fission track ages (FTA) of apatite, their distribution patterns and hints over the tectonics activities during Mesozoic and Cenozoic in the east Dabie area. Attempts were also made to improve the conventional statistical method for the tracks. Ranging from 59.4 +- 3.4 Ma to 105.6 +- 9.8 Ma, the FTA results of apatite spread in the wide range and increased rapidly from the east to the west area. Sine 95 Ma, the uplift rate has been quite slow and asymmetry. The FTA value in the middle area of Xiaotian-Mozitan Fault may imply its uplift in Cretaceous. The faulting should be the main control factor for the uplift of this area

  17. Apatite/Melt Partitioning Experiments Reveal Redox Sensitivity to Cr, V, Mn, Ni, Eu, W, Th, and U

    Science.gov (United States)

    Righter, K.; Yang, S.; Humayun, M.

    2016-01-01

    Apatite is a common mineral in terrestrial, planetary, and asteroidal materials. It is commonly used for geochronology (U-Pb), sensing volatiles (H, F, Cl, S), and can concentrate rare earth elements (REE) during magmatic fractionation and in general. Some recent studies have shown that some kinds of phosphate may fractionate Hf and W and that Mn may be redox sensitive. Experimental studies have focused on REE and other lithophile elements and at simplified or not specified oxygen fugacities. There is a dearth of partitioning data for chalcophile, siderophile and other elements between apatite and melt. Here we carry out several experiments at variable fO2 to study the partitioning of a broad range of trace elements. We compare to existing data and then focus on several elements that exhibit redox dependent partitioning behavior.

  18. Apatite as a record of extreme differentiation in the uppermost part of the Bushveld Complex (Invited)

    Science.gov (United States)

    Vantongeren, J. A.; Mathez, E. A.

    2010-12-01

    The Bushveld Complex consists of an 8 km+-thick sequence of ultramafic to dioritic cumulate rocks. As expected for such rocks, concentrations of incompatible trace elements are low compared to typical basalts, suggesting the existence of a residual magma that had escaped from the original chamber. VanTongeren et al. (2010 Journal of Petrology vol. 51, no. 9, p. 1891-1912) proposed that the missing magma is represented by portions of the overlying Rooiberg Group rhyolites or associated Rashoop granophyres, both of which have traditionally been regarded as older than the Bushveld cumulates despite possessing a similar age and Sr isotopic composition. The hypothesis that the felsic rocks originated from the Bushveld chamber is supported by phase equilibria and certain geochemical characteristics of the cumulate sequence. To test this hypothesis further, we determined by EPMA and LA-ICPMS the minor and trace element contents of apatite and other coexisting cumulus phases in the top 500 m of the section, the rationale being that the missing magma likely escaped from near the top of the chamber. Apatite should be a particularly good recorder of the composition of a coexisting liquid because it contains high abundances of REEs, Y, and other typically incompatible elements. Using published partition coefficients, we calculate the composition of the equilibrium liquid at the top of the Bushveld Complex and compare it with those of the Rooiberg and Rashoop rocks. Our results show that the cumulates near the top of the Bushveld Complex were in trace element equilibrium with a liquid similar in composition to those felsic rocks. We therefore conclude that (1) the Bushveld magma evolved by fractional crystallization to a rhyolitic composition; (2) portions of the Rooiberg and/or Rashoop roof rocks represent the residual liquids after extensive fractional crystallization of the Bushveld magmas; and (3) if some of the extrusive rocks directly overlying the Bushveld were derived

  19. Vacuum-sintered body of a novel apatite for artificial bone

    Science.gov (United States)

    Tamura, Kenichi; Fujita, Tatsushi; Morisaki, Yuriko

    2013-12-01

    We produced regenerative artificial bone material and bone parts using vacuum-sintered bodies of a novel apatite called "Titanium medical apatite (TMA®)" for biomedical applications. TMA was formed by chemically connecting a Ti oxide molecule with the reactive [Ca10(PO4)6] group of Hydroxyapatite (HAp). The TMA powders were kneaded with distilled water, and solid cylinders of compacted TMA were made by compression molding at 10 MPa using a stainless-steel vessel. The TMA compacts were dried and then sintered in vacuum (about 10-3 Pa) or in air using a resistance heating furnace in the temperature range 1073-1773 K. TMA compacts were sintered at temperatures greater than 1073 K, thus resulting in recrystallization. The TMA compact bodies sintered in the range 1273-1773 K were converted into mixtures composed of three crystalline materials: α-TCP (tricalcium phosphate), β-TCP, and Perovskite-CaTiO3. The Perovskite crystals were stable and hard. In vacuum-sintering, the Perovskite crystals were transformed into fibers (approximately 1 µm in diameter × 8 µm in length), and the fiber distribution was uniform in various directions. We refer to the TMA vacuum-sintered bodies as a "reinforced composite material with Perovskite crystal fibers." However, in atmospheric sintering, the Perovskite crystals were of various sizes and were irregularly distributed as a result of the effect of oxygen. After sintering temperature at 1573 K, the following results were obtained: the obtained TMA vacuum-sintered bodies (1) were white, (2) had a density of approximately 2300 kg/m3 (corresponding to that of a compact bone or a tooth), and had a thermal conductivity of approximately 31.3 W/(m·K) (corresponding to those of metal or ceramic implants). Further, it was possible to cut the TMA bodies into various forms with a cutting machine. An implant made of TMA and inserted into a rabbit jaw bone was covered by new bone tissues after just one month because of the high

  20. Apatite fission track implications for timing of hydrothermal fluid flow in Tertiary volcanics of the Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Filip, Jiří; Ulrych, Jaromír; Adamovič, Jiří; Balogh, K.

    2007-01-01

    Roč. 52, 3-4 (2007), s. 211-220. ISSN 0449-2560 R&D Projects: GA AV ČR IAA3013403 Grant ostatní: OTKA(HU) T060965; OTKA(HU) M41434 Institutional research plan: CEZ:AV0Z30130516 Keywords : Bohemian Massif * fission tracks * apatite * K-Ar dating * volcanic rocks * thermal events * stress field Subject RIV: DB - Geology ; Mineralogy

  1. In situ Sr/Sr investigation of igneous apatites and carbonates using laser-ablation MC-ICP-MS

    DEFF Research Database (Denmark)

    Bizzarro, Martin; Simonetti, A.; Stevenson, R.K.;

    2003-01-01

    In situ Sr isotopic compositions of coexisting apatite and carbonate for carbonatites from the Sarfartoq alkaline complex, Greenland, have been determined by laser-ablation multicollector inductively coupled plasma mass spectrometry. This study is the first to examine the extent of Sr isotopic...... (regional) scale open-system processes, possibly involving mixing of carbonatitic melts derived from distinct mantle sources or from a common isotopically heterogeneous mantle. Copyright © 2003 Elsevier Science Ltd....

  2. The possibility of the formation of protocells and their structural components on the basis of the apatite matrix and cocrystallizing minerals.

    Science.gov (United States)

    Kostetsky, Eduard Y

    2005-12-01

    This paper presents the author's theory on the possibility of simultaneous hard-phase synthesis of various organic molecules from gas-phase elements on the basis of the apatite matrix and cocrystallizing minerals (carbonate-apatite, calcite, mica). These molecules and their ensembles gave rise to living systems and protocells of the pro- and eukaryotic types. Synthesis might have occurred through gradual substitution of the mineral matrix by crystal organic matter. The structure and size of the molecules synthesized were determined by the structure, physical parameters, and arrangement of organizing centers in the crystal lattice. Apatite phosphates were embedded in a synthesized nucleic helix and their size and purine-pyrimidine complementarity were determined. Apatite and cocrystallizing minerals were seen to be involved in the synthesis of four basic classes of cell components: apatite-DNA and nucleoproteide complexes; carbonate-apatite-enzymes, other proteins involved in DNA replication, all RNA types and their complexes with the specific proteins and enzymes of transcription and translation; calcite-cytoskeletal proteins; and mica-membrane lipids and proteins. The evidence supporting this theory is presented. A possible mechanism to account for the transition from crystal through organo-mineral crystal to liquid crystal (protocell) and a model of the occurrence of the matrix mechanism of transcription and translation are proposed. Some principal problems in the biochemistry and molecular biology of the origin of life on the Earth are discussed. PMID:23345922

  3. Inhibition of precipitation of carbonate apatite by trisodium citrate analysed in base of the formation of chemical complexes in growth solution

    Science.gov (United States)

    Prywer, Jolanta; Olszynski, Marcin; Mielniczek-Brzóska, Ewa

    2015-11-01

    Effect of trisodium citrate on the precipitation of carbonate apatite is studied. The experimental series are performed in the solution of artificial urine. The investigations are related to infectious urinary stones formation as carbonate apatite is one of the main components of this kind of stones. To mimic a real infection in urinary tract the aqueous ammonia solution was added to the solution of artificial urine. The spectrophotometric results demonstrate that trisodium citrate increases induction time with respect to carbonate apatite formation and decreases the efficiency of carbonate apatite precipitation. The inhibitory effect of trisodium citrate on the precipitation of carbonate apatite is explained in base of chemical speciation analysis. Such an analysis demonstrates that the inhibitory effect is mainly related with the fact that trisodium citrate binds Ca2+ ions and causes the formation of CaCit- and Ca10(PO4)6CO3 complexes. Trisodium citrate binds Ca2+ ions in the range of pH from 6 to 9.5 for which carbonate apatite is favored to be formed.

  4. On the mechanism of apatite-induced precipitation on 45S5 glass pellets coated with a natural-derived polymer

    Science.gov (United States)

    Araújo, Marco; Miola, Marta; Bertone, Elisa; Baldi, Giovanni; Perez, Javier; Verné, Enrica

    2015-10-01

    In this work, the bioactive glass 45S5 (also known by its commercial name Bioglass®) was successfully dip-coated by a natural derived biopolymer, increasing its apatite-forming ability. The biopolymer was shown to accelerate the first stages of bioactivity, inducing a fast transition to step 4 (formation of amorphous Casbnd P layer) in the apatite-forming ability mechanism. The faster precipitation of Ca/P crystals in the coated samples resulted in the formation of an intermediate amorphous octacalcium phosphate, which later transforms into an apatite layer with high thickness. The effect of the thickness of the coating was also studied on samples coated with polymer suspensions of different concentrations (0.15% and 1.5%, w/v), revealing that the kinetics of formation of the final hydroxycarbonate apatite layer increases with the thickness of the coating. The mechanism by which this apatite-forming ability is accelerated was also investigated, revealing that certain functional groups present in the structure of the polymer allow it to act as an organic matrix and preferential nucleation site for the growth of the hydroxycarbonate apatite layer.

  5. In vitro mineralization of bioresorbable poly(ɛ-caprolactone)/apatite composites for bone tissue engineering: a vibrational and thermal investigation

    Science.gov (United States)

    Taddei, Paola; Tinti, Anna; Reggiani, Matteo; Fagnano, Concezio

    2005-06-01

    This study was aimed at evaluating the physico-chemical properties of a porous poly(ɛ-caprolactone)/carbonated-apatite (PCL/CAp 30/70 w/w) composite to be used as scaffold for bone tissue engineering. The in vitro degradation mechanism of this matrix in different media was evaluated as well as its bioactivity in a simulated body fluid (SBF) buffered at pH 7.4 (37 °C, 28 days). For this purpose, we used vibrational IR and Raman spectroscopy coupled to thermogravimetry (TG) and differential scanning calorimetry (DSC). The samples were analyzed before and after immersion in the above mentioned solution as well as in 0.01 M NaOH solution (pH=12), saline phosphate buffer at pH 7.4 (SPB) and esterase/SPB. A control PCL sample was analyzed before the addition of the apatitic component. As regards the untreated samples, the method of synthesis utilized for preparing the composite was found to lower the crystallinity degree. The CAp component revealed to be constituted of a B-type CAp with a 3% carbonate content. After immersion in SBF solution, vibrational analysis coupled to TG revealed the deposition of a significant amount of an apatite component on the surface of the PCL/CAp composite as well as in its interior, showing a good in vitro mineralization.

  6. The structure, bond strength and apatite-inducing ability of micro-arc oxidized tantalum and their response to annealing

    Science.gov (United States)

    Wang, Cuicui; Wang, Feng; Han, Yong

    2016-01-01

    In this study, the tantalum oxide coatings were formed on pure tantalum (Ta) by micro-arc oxidation (MAO) in electrolytic solutions of calcium acetate and β-glycerophosphate disodium, and the effect of the applied voltage on the microstructure and bond strength of the MAO coatings was systematically investigated. The effect of annealing treatment on the microstructure, bond strength and apatite-inducing ability of the MAO coatings formed at 350 and 450 V was also studied. The study revealed that during the preparation of tantalum oxide coatings on Ta substrate by MAO, the applied voltage considerably affected the phase components, morphologies and bond strength of the coatings, but had little effect on surface chemical species. After annealing treatment, newly formed CaTa4O11 phase mainly contributed to the much more stronger apatite-inducing ability of the annealed tantalum oxide coatings than those that were not annealed. The better apatite-inducing ability of the MAO coatings formed at 450 V compared to those formed at 350 V was attributed to the less amorphous phase and more crystalline phase as well as more Ca and P contained in the MAO coatings with increasing the applied voltage.

  7. Application of apatite fission tract analysis to problems of Mississippi Valley-type Pb-Zn ore genesis

    International Nuclear Information System (INIS)

    Epigenetic, carbonate-hosted Pb-Zn mineralization of the Mississippi Valley-Type (MVT) is considered to form from warm basinal brines in the temperature range 50-200 deg.C. A variety of genetic fluid flow models have been proposed to explain MVT mineralization, but all suffer from a lack of constraint concerning the timing of ore formation. Fission tracks in apatite resulting from the spontaneous decay of trace amounts of 238U are thermally unstable over the range of temperatures proposed for MVT ore formation, and may therefore record thermal events related to Pb-Zn mineralization provided sufficient time is allowed for track annealing to occur. Zinc mineralization in Devonian carbonates of the Lennard Shelf, northwest Australia is also considered to be of the Mississippi Valley-type. Mean apatite ages from Precambrian basement and from Devonian carbonates generally average 300Ma. Studies of well sequences indicate a period of uplift for the Lennard Shelf area around the Late Triassic/Early Jurassic. For carbonate outcrop samples, a thermal history is proposed involving burial in the Late Paleozoic/Early Mesozoic followed by uplift and cooling from peak temperatures around 70 deg.C. No difference in apatite annealing effects are observed in the vicinity of zinc mineralization. Coupled with other evidence, this suggests that the mineralizing episode was of short duration given temperatures of ore formation in the range 70-110 deg.C indicated by fluid inclusion homogenization temperatures. 3 refs

  8. Apatite, SiO2, rutile and orthopyroxene precipitates in minerals of eclogite xenoliths from Yakutian kimberlites, Russia

    Science.gov (United States)

    Alifirova, T. A.; Pokhilenko, L. N.; Korsakov, A. V.

    2015-06-01

    Eclogite mantle xenoliths from the central part of Siberian craton (Udachnaya and Zarnitsa kimberlite pipes) as well as from the northeastern edge of the craton (Obnazhennaya kimberlite) were studied in detail. Garnet and clinopyroxene show evident exsolution textures. Garnet comprises rutile, ilmenite, apatite, and quartz/coesite oriented inclusions. Clinopyroxene contains rutile (± ilmenite) and apatite precipitates. Granular inclusions of quartz in kyanite and garnet usually retain features of their high-pressure origin. According to thermobarometric calculations, the studied eclogitic suite was equilibrated within lithospheric mantle at 3.2-4.9 GPa and 813-1080 °C. The precursor composition of garnets from Udachnaya and Zarnitsa eclogites suggests their stability at depths 210-260 km. Apatite precipitation in clinopyroxenes of Udachnaya and Zarnitsa allows us to declare that original pyroxenes could have been indicative of their high P-T stability. Raman spectroscopic study of quartz and coesite precipitates in garnet porphyroblasts confirms our hypothesis on the origin of the exsolution textures during pressure-temperature decrease. With respect to mineralogical data, we suppose the rocks to be subjected to stepwise decompression and cooling within mantle reservoir.

  9. Ca L2,3-edge XANES and Sr K-edge EXAFS study of hydroxyapatite and fossil bone apatite

    Science.gov (United States)

    Zougrou, I. M.; Katsikini, M.; Brzhezinskaya, M.; Pinakidou, F.; Papadopoulou, L.; Tsoukala, E.; Paloura, E. C.

    2016-08-01

    Upon burial, the organic and inorganic components of hard tissues such as bone, teeth, and tusks are subjected to various alterations as a result of interactions with the chemical milieu of soil, groundwater, and presence of microorganisms. In this study, simulation of the Ca L 2,3-edge X-ray absorption near edge structure (XANES) spectrum of hydroxyapatite, using the CTM4XAS code, reveals that the different symmetry of the two nonequivalent Ca(1) and Ca(2) sites in the unit cell gives rise to specific spectral features. Moreover, Ca L 2,3-edge XANES spectroscopy is applied in order to assess variations in fossil bone apatite crystallinity due to heavy bacterial alteration and catastrophic mineral dissolution, compared to well-preserved fossil apatite, fresh bone, and geologic apatite reference samples. Fossilization-induced chemical alterations are investigated by means of Ca L 2,3-edge XANES and scanning electron microscopy (SEM) and are related to histological evaluation using optical microscopy images. Finally, the variations in the bonding environment of Sr and its preference for substitution in the Ca(1) or Ca(2) sites upon increasing the Sr/Ca ratio is assessed by Sr K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy.

  10. Effect of geometrical structure on drug release rate of a three-dimensionally perforated porous apatite/collagen composite cement.

    Science.gov (United States)

    Otsuka, Makoto; Nakagawa, Hidenori; Ito, Atsuo; Higuchi, William I

    2010-01-01

    To improve the biocompatibility, inter-connective pore structure, and drug delivery ability of self-setting apatite/collagen composite cement (ACC), a three-dimensionally perforated porous apatite/collagen composite cement (TPPACC) containing 3% indomethacin (IMC) was obtained in an arranged multi-cross with 20, 40, and 60 stainless steel needlelike male dies, and stored and hardened at 37 degrees C and 100% relative humidity for 24 h. The mean radius of micro-pores of the TPPACC was evaluated to be 0.125 microm by mercury porosimetry. X-ray powder diffraction and FT-IR spectroscopy suggested that TPPACC consisted of carbonated apatite and had a structure similar to that of natural rat bone. The IMC release rates from a TPPACC block containing the drug were measured in simulated body fluid. The rate of release increased with the number of macro-pores that from planar surface matrix systems followed the Higuchi equation. The relationship between the Higuchi constant and surface area of TPPACC showed a straight line with K = 0.2123 and R(2) = 0.9892. These results indicated that the rate of drug release from TPPACC could be controlled by the number of macro-pores for bone cells. PMID:19821491

  11. Apatite ore mine tailings as an amendment for remediation of a lead-contaminated shooting range soil.

    Science.gov (United States)

    Venäläinen, Salla H

    2011-10-01

    This study investigated the use of tailings from apatite ore beneficiation in the remediation of a heavily contaminated shooting range soil. The tailings originating in Siilinjärvi carbonatite complex, Finland, consist of apatite residues accompanied by phlogopite and calcite. In a pot experiment, organic top layer of a boreal forest soil predisposed to pellet-derived lead (Pb) was amended with tailings of various particle-sizes (Ø>0.2mm, Ø<0.2mm and unsieved material) differing in their mineralogical composition. After 9-, 10-, 14- and 21-month incubation, the samples were monitored for tailings-induced changes in the different Pb pools by means of sequential fractionation. Following the incubation, the samples were extracted with water and the extracts were analyzed for Pb species distribution by means of a cation exchange resin. The results revealed that Pb was continuously released from the shotgun pellet fragments due to weathering. However, the apatite and calcite compartments in the tailings counteracted the mobility of the released Pb through the formation of sparingly soluble fluorpyromorphite and cerussite. Furthermore, the tailings efficiently reduced the bioavailability of Pb by transferring it from the water-soluble and exchangeable pools into the organic one. The material also increased the proportion of the less toxic non-cationic Pb to the total dissolved Pb from the initial level of 5% to 9-12%. The results suggest that the tailings-induced stabilization of Pb may be an environmentally sound remediation technique at polluted sites. PMID:21871651

  12. Revisiting the localization of Zn2+ cations sorbed on pathological apatite calcifications made through X-ray absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bazin, D.; Carpentier, X.; Brocheriou, I.; Dorfmuller, P.; Aubert, S.; Chappard, C.; Thiaudiere, D.; Reguer, S.; Waychunas, G.; Jungers, P.; Daudon, M.

    2009-04-01

    The role of oligo-elements such as Zn in the genesis of pathological calcifications is widely debated in the literature. An essential element of discussion is given by their localization either at the surface or within the Ca apatite crystalline network. To determine the localization, X-ray absorption experiments have been performed at SOLEIL. The Exafs results suggest that Zn atoms, present in the Zn{sup 2+} form, are bound to about 4 O atoms at a distance of 2.00{angstrom}, while the interatomic distance R{sub CaO} ranges between 2.35 {angstrom} and 2.71 {angstrom}. Taking into account the content of Zn (around 1000 ppm) and the difference in ionic radius between Zn{sup 2+} (0.074 nm) and Ca{sup 2+} (0.099 nm), a significant longer interatomic distance would be expected in the case of Zn replacing Ca within the apatite crystalline network. We thus conclude that Zn atoms are localized at the surface and not in the apatite nanocrystal structure. Such structural result has essential biological implications for at least two reasons. Some oligoelements have a marked effect on the transformation of chemical phases, and may modify the morphology of crystals. These are both major issues because, in the case of kidney stones, the medical treatment depends strongly on the precise chemical phase and on the morphology of the biological entities at both macroscopic and mesoscopic scales.

  13. The Influence of Surface Morphology of Dense Ca-P Ceramics on Apatite Formation in Dynamic SBF

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    This study aimed at exploring the effect of surface morphology of dense phosphate calcium (Ca-P) ceramics upon the formation of bone-like apatite in static or dynamic simulated body fluid (SBF). Dense and sandblasted calcium phosphate ceramics were immersed into dynamic SBF flowing at normal physiological speed of body fluid of skeletal muscle.The changes were characterized using SEM, XPS, IR and XRD. Changes can be observed after the sandblasted surface of dense calcium phosphate ceramics had been immersed in SBF for 14 days. XPS analysis results showed that the flake-like structure was composed of Ca, P, C, O; IR analysis result of surface structure of samples showed that there were specific peaks for CO2-3; XRD results indicated the decrease in crystallinity and the increase in amorphous structure. The rough surface was advantageous for the formation of bone-like apatite. Increasing the Ca2+, HPO2-4 concentration of SBF could also enhance the bone like apatite formation. All the results demonstrated that local concentration is a key factor affecting nucleation.

  14. Quinone-rich polydopamine functionalization of yttria stabilized zirconia for apatite biomineralization: The effects of coating temperature

    Science.gov (United States)

    Zain, Norhidayu Muhamad; Hussain, Rafaqat; Abdul Kadir, Mohammed Rafiq

    2015-08-01

    The use of yttria stabilized zirconia (YSZ) as biomedical implants is often offset by its bioinert nature that prevents its osseointegration to occur. Therefore, the functionalization of YSZ surface by polydopamine to facilitate the biomineralization of apatite layer on top of the coated film has incessantly been studied. In this study YSZ discs were first immersed in 2 mg/mL of stirred dopamine solution at coating temperatures between 25 and 80 °C. The specimens were then incubated for 7d in 1.5 SBF. The effect of coating temperature on the properties (chemical compositions and wettability) and the apatite mineralization on top of the generated films was investigated. It was found that at 50 °C, the specimen displayed the highest intensity of Ca 2p peak (1.55 ± 0.42 cps) with Ca/P ratio of 1.67 due to the presence of abundant quinone groups (Cdbnd O). However, the hydrophilicity (40.9 ± 01.7°) was greatly improved at 60 °C accompanied by the highest film thickness of 306 nm. Therefore, it was concluded that the presence of high intensity of quinone groups (Cdbnd O) in polydopamine film at elevated temperature affects the chelation of Ca2+ ions and thus enhance the growth of apatite layer on top of the functionalized YSZ surface.

  15. Apatite fission track analysis on tectonic activities and paleotopography in southern Altai region, Xinjiang, China

    International Nuclear Information System (INIS)

    This work engages apatite fission track evidences on thermotectonic history, rock uplift rate, denudation extent southeastern Altai region. Fission track ages of 14 samples range from (59.4±5.8) Ma to (109.7±8.1) Ma and the length is between (12.0±2.5) μm and (13.7±1.5) μm. Thermal modeling reveals that the samples have a three-stage of uplift-cooling history. The first stage is in an overall initial uplift before 108 Ma, the second stage from 108 Ma to 28 Ma experiences a slow cooling phase, and the last stage through a rapid-cooling process since 28 Ma with a cooling rate 1.25 1.61 ℃/Ma and denudation amount 1.17-1.50 km, the fast exhumation period in the area. The sample ages could be divided into 4 age groups, reflecting multiple tectonic events with different uplift rates. The paleotopography altitude changes from 3895 m to 821 m, 2250 m to 762 m etc., and the amplitude of changes reaches to 3300-1400 m since 90 Ma. The phenomenon of Alpine turning to valley and valley uplifting is visible in the studied area, indicating various stages of paleotopography. Based on inversion of ancient landforms and equilibrium correction, the equilibrium rebound would play an important role in the rock uplift during the Altai post-orogenic period. (authors)

  16. Apatite phosphates containing heterovalent cations and their application in Knoevenagel condensation

    Energy Technology Data Exchange (ETDEWEB)

    Priya, K. [Materials Division - Chemistry, School of Science and Humanities, VIT University, Vellore 632014, Tamil Nadu (India); Buvaneswari, G., E-mail: gopalbhu@yahoo.com [Materials Division - Chemistry, School of Science and Humanities, VIT University, Vellore 632014, Tamil Nadu (India)

    2009-06-03

    Apatite structure type ortho phosphates of the formula NaLaCa{sub 3}(PO{sub 4}){sub 3}OH and NaLaSr{sub 3}(PO{sub 4}){sub 3}OH have been synthesized via a simple solution route. The compounds are isostructural with calcium hydroxyapatite. The phases are characterized by powder X-ray diffraction method and infrared spectroscopy. The unit cell parameters are: for NaLaCa{sub 3}(PO{sub 4}){sub 3}OH, a = 9.457(3) and c = 6.90(1) A and for NaLaSr{sub 3}(PO{sub 4}){sub 3}OH, a = 9.720(3) and c = 7.23(3) A, respectively. Knoevenagel condensation of selected aldehydes and molecules with activated methylene group is carried out using the phosphates as solid supports. Both phases facilitated the condensation reaction at room temperature in the absence of a solvent. An increase in the yield of the products is noticed when the supports are used with water.

  17. Apatite formation on active nanostructured coating based on functionalized gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Vasile, Eugeniu [METAV Research and Development (Romania); Serafim, Andrada; Dragusin, Diana-Maria; Petrea, Celina; Iovu, Horia; Stancu, Izabela-Cristina, E-mail: stancu.c.i@gmail.com [University Politehnica of Bucharest, Advanced Polymer Materials Group (Romania)

    2012-06-15

    In this work, we developed a simple method of surface functionalization of polymer substrates to provide them with the ability to form biomimetic hydroxyapatite (HA) when incubated in synthetic body fluids (SBF). In a first step, gold nanoparticles (AuNPs) were used as surface nanostructuring units for a biocompatible polymer, poly(2-hydroxyethyl methacrylate), known to not promote biomineralization in SBF, and under physiological conditions. The treatment of AuNPs-modified substrate with mercaptosuccinic acid leads to brushes of carboxyl-ended chains self-assembled onto the gold-polymer hybrid nanosurface. The main aim of this work was to demonstrate that these multianionic nanosurfaces would induce HA formation when incubated in solutions mimicking physiologic conditions. The formation of apatite and its morphology and composition were successfully investigated by means of high resolution scanning and transmission electron microscopy with energy dispersive X-ray microanalysis, infrared spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. Emphasis was put on the nucleation of HA in areas with agglomerated carboxyl-ended functionalized nanoparticles. The results obtained in this study may unlock new applications for smart active coatings based on functionalized AuNPs, such as the induction of biomineralization.

  18. Prompt isothermal decay of thermoluminescence in an apatite exhibiting strong anomalous fading

    International Nuclear Information System (INIS)

    Highlights: • The Isothermal TL of a material exhibiting strong AF is very peculiar. • The Isothermal TL curves are very well fitted using a newly proposed tunneling model. • The decay constants are found to be independent on temperature. • The explanation requires tunneling recombination from different excited energy levels. -- Abstract: Anomalous fading (AF) is one of the most serious drawbacks in thermoluminescence (TL) and optically stimulated luminescence (OSL) dating. In the present work the isothermal decay of TL signals from Durango apatite is studied for temperatures located on the rising part of the main TL peak. This material is known to exhibit strong AF phenomena, and its isothermal TL decay properties have not been studied previously. The experimental results show that the characteristic decay time of the isothermal signal does not depend of the temperature, and that this signal does not exhibit the strong temperature dependence expected from conventional TL kinetic theories. This is further direct experimental evidence for the possible presence of tunneling phenomena in this material. The isothermal decay curves are analyzed and discussed within the framework of conventional theories of TL, as well as within the context of a recently developed tunneling kinetic model for random distributions of electron-hole pairs in luminescent materials

  19. Osteointegration of biomimetic apatite coating applied onto dense and porous metal implants in femurs of goats.

    Science.gov (United States)

    Barrère, F; van der Valk, C M; Meijer, G; Dalmeijer, R A J; de Groot, K; Layrolle, P

    2003-10-15

    Biomimetic calcium phosphate (Ca-P) coatings were applied onto dense titanium alloy (Ti6Al4V) and porous tantalum (Ta) cylinders by immersion into simulated body fluid at 37 degrees C and then at 50 degrees C for 24 h. As a result, a homogeneous bone-like carbonated apatitic (BCA) coating, 30 microm thick was deposited on the entire surface of the dense and porous implants. Noncoated and BCA-coated implants were press-fit implanted in the femoral diaphysis of 14 adult female goats. Bone contact was measured after implantation for 6, 12, and 24 weeks, and investigated by histology and backscattered electron microscopy (BSEM). After 6 weeks, bone contact of the BCA-coated Ti6Al4V implants was about 50%. After 12 and 24 weeks, bone contact was lower in comparison with the 6-week implantations at, respectively 24 and 39%. Regarding the BCA-coated porous Ta implants, bone contacts were 17, 30, and 18% after 6, 12, and 24 weeks, respectively. However, bone contact was always found significantly higher for BCA-coated dense Ti6Al4V and porous Ta cylinders than the corresponding noncoated implants. The results of this study show that the BCA coating enhances the bone integration as compared to the noncoated implants. PMID:14528464

  20. In vivo biocompatibility of custom-fabricated apatite-wollastonite-mesenchymal stromal cell constructs.

    Science.gov (United States)

    Lee, Jennifer A; Knight, Charlotte A; Kun, Xiao; Yang, Xuebin B; Wood, David J; Dalgarno, Kenneth W; Genever, Paul G

    2015-10-01

    We have used the additive manufacturing technology of selective laser sintering (SLS), together with post SLS heat treatment, to produce porous three dimensional scaffolds from the glass-ceramic apatite-wollastonite (A-W). The A-W scaffolds were custom-designed to incorporate a cylindrical central channel to increase cell penetration and medium flow to the center of the scaffolds under dynamic culture conditions during in vitro testing and subsequent in vivo implantation. The scaffolds were seeded with human bone marrow mesenchymal stromal cells (MSCs) and cultured in spinner flasks. Using confocal and scanning electron microscopy, we demonstrated that MSCs formed and maintained a confluent layer of viable cells on all surfaces of the A-W scaffolds during dynamic culture. MSC-seeded, with and without osteogenic pre-differentiation, and unseeded A-W scaffolds were implanted subcutaneously in MF1 nude mice where osteoid formation and tissue in-growth were observed following histological assessment. The results demonstrate that the in vivo biocompatibility and osteo-supportive capacity of A-W scaffolds can be enhanced by SLS-custom design, without the requirement for osteogenic pre-induction, to advance their potential as patient-specific bone replacement materials. PMID:25777813

  1. Bioactive glasses with improved processing. Part 1. Thermal properties, ion release and apatite formation.

    Science.gov (United States)

    Groh, Daniel; Döhler, Franziska; Brauer, Delia S

    2014-10-01

    Bioactive glasses, particularly Bioglass® 45S5, have been used to clinically regenerate human bone since the mid-1980s; however, they show a strong tendency to undergo crystallization upon heat treatment, which limits their range of applications. Attempts at improving their processing (by reducing their tendency to crystallize) have included increasing their silica content (and thus their network connectivity), incorporating intermediate oxides or reducing their phosphate content, all of which reduce glass bioactivity. Therefore, bioactive glasses known for their good processing (e.g. 13-93) are considerably less bioactive. Here, we investigated if the processing of 45S5 bioactive glass can be improved while maintaining its network connectivity and phosphate content. The results show that, by increasing the calcium:alkali cation ratio, partially substituting potassium for sodium (thereby making use of the mixed alkali effect) and adding small amounts of fluoride, bioactive glasses can be obtained which have a larger processing window (suggesting that they can be processed more easily, allowing for sintering of scaffolds or drawing into fibres) while degrading readily and forming apatite in aqueous solution within a few hours. PMID:24880003

  2. Novel development of carbonate apatite-chitosan scaffolds based on lyophilization technique for bone tissue engineering

    Directory of Open Access Journals (Sweden)

    Maretaningtias Dwi Ariani

    2012-09-01

    Full Text Available Background: The natural biopolymer chitosan (Ch is currently regarded as a candidate for bone tissue engineering. However, Ch is poor for cell adhesion and low bone formation ability. In order to enhance cell adhesion and bone formation ability, combination of Ch with carbonate apatite (CA was developed. Purpose: The aim of this study was to make carbonate apatite-chitosan scaffolds (CAChSs and evaluate its osteoconductivity in terms of cell proliferation. Methods: Chitosan scaffolds (ChSs were made by the following procedure. Twenty-five, 50, 100, 200 and 400 mg Ch was dissolved into 5 ml of 2% acetic acid (CH3COOH, shaked for 15 min and neutralized with 15 ml of 0.1 M sodium hydroxide (NaOH solution. After centrifugation, Ch gel was packed into the molds then frozen at -80°C for 2h and dried in a freeze dry machine for 24h. The sponges were subjected to UV radiation for 2h. To make CA-ChSs, 200 mg Ch was selected. After neutralization, 50 mg of 0.06 M CA were added into the 200 mg Ch gel. The structure of CA-ChSs was observed by scanning electron microscope (SEM. Mouse osteoblast-like cell (MC3T3-E1 proliferation in these scaffolds was investigated at 1, 7, 14 and 21 days. Results: Three dimensional porous structures of CA-ChSs were clearly observed by SEM. Proliferated cell numbers in CA-ChSs was significantly higher than those in ChSs (control at each stage (p<0.05. Conclusion: It can be concluded that newly developed CA-ChSs had three-dimensional interconnected porous structure, good handling property and supporting ability of proliferation of osteoblasts. It is suggested that newly developed CA-ChSs could be considered as a scaffolds material for bone tissue enginearing.Latar belakang: Kitosan yang merupakan biopolimer alami dianggap sebagai salah satu kandidat untuk rekayasa jaringan tulang. Namun, kitosan memiliki kelemahan terhadap adhesi sel dan kurang mampu membentuk tulang yang cukup. Untuk meningkatkan adhesi sel dan kemampuan

  3. Ni(II immobilization by bio-apatite materials: Appraisal of chemical, thermal and combined treatments

    Directory of Open Access Journals (Sweden)

    Šljivić-Ivanović Marija

    2016-01-01

    Full Text Available Animal bones are natural and rich source of calcium hydroxyapatite (HAP, which was found to be a good sorbent material for heavy metals and radionuclides. Various treatments can reduce the content of bone organic phase and improve sorption properties. In this study, sorption capacities of raw bovine bones (B and samples obtained by chemical treatment with NaOH (BNaOH, by heating at 400 oC (B400 and by combined chemical and thermal treatment (BNaOH+400, were compared, using Ni(II ions as sorbates. Maximum sorption capacities increased in the order Bapatite based material with low organic content and high efficiency for Ni(II sorption, it is also a good candidate for in-situ soil remediation, particularly at lower contamination levels. [Projekat Ministarstva nauke Republike Srbije, br. III 43009

  4. Constraining the stepwise migration of the eastern Tibetan Plateau margin by apatite fission track thermochronology

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Granites sampled from Garzê-Litang thrust, Longmen Shan thrust, Garzê and Litang strike-slip faults in the eastern Tibetan Plateau have been analyzed with apatite fission track thermochronological method in this study. The measured fission track apparent ages, combined with the simulated annealing mod- eling of the thermal history, have been used to reconstruct the thermal evolutionary histories of the samples and interpret the active history of the thrusts and faults in these areas. Thermal history mod- eling shows that earlier tectonic cooling occurred in the Garzê-Litang thrust in Miocene (~20―16 Ma) whereas the later cooling occurred mainly in the Longmen Shan thrust since ~5 Ma. Our study sug- gests that the margin of eastern Tibetan Plateau was extended by stages: through strike-slip faults deformations and related thrusts, the upper crust formed the Garzê-Litang margin in the Miocene epoch and then moved to the Longmen Shan margin since ~5 Ma. During this process, the deformations of different phases in the eastern Tibetan Plateau were absorbed by the thrusts within them and conse- quently the tectonic events of long-distance slip and extrusion up to hundreds of kilometers have not been found.

  5. Constraining the stepwise migration of the eastern Tibetan Plateau margin by apatite fission track thermochronology

    Institute of Scientific and Technical Information of China (English)

    LAI QingZhou; DING Lin; WANG HongWei; YUE YaHui; CAI FuLong

    2007-01-01

    Granites sampled from Garzê-Litang thrust, Longmen Shan thrust, Garzê and Litang strike-slip faults in the eastern Tibetan Plateau have been analyzed with apatite fission track thermochronological method in this study. The measured fission track apparent ages, combined with the simulated annealing modeling of the thermal history, have been used to reconstruct the thermal evolutionary histories of the samples and interpret the active history of the thrusts and faults in these areas. Thermal history modeling shows that earlier tectonic cooling occurred in the Garzê-Litang thrust in Miocene (~20―16 Ma) whereas the later cooling occurred mainly in the Longmen Shan thrust since ~5 Ma. Our study suggests that the margin of eastern Tibetan Plateau was extended by stages: through strike-slip faults deformations and related thrusts, the upper crust formed the Garzê-Litang margin in the Miocene epoch and then moved to the Longmen Shan margin since ~5 Ma. During this process, the deformations of different phases in the eastern Tibetan Plateau were absorbed by the thrusts within them and consequently the tectonic events of long-distance slip and extrusion up to hundreds of kilometers have not been found.

  6. [A novel europium doped apatite/wollastonite porous magnetic bioactive glass ceramic].

    Science.gov (United States)

    Zhang, Wangzhi; Zhou, Dali; Yang, Weizhong; Yin, Guangfu; Ou, Jun

    2007-08-01

    A new biocompatible apatite-wollastonite magnetic glass ceramic has been synthesized via sol-gel process. Characteristics of the materials were determined with differential thermal analysis (DTA), X-ray diffraction (XRD), scan electron microscopy (SEM), energy dispersive spectrum (EDS), inductively couple plasma atomic emission spectroscopy (ICP-AES), vibrating sample magnetometer (VSM) and so on. Results showed that the main crystalline phases of the material were hydroxyapatite/fluoroapatite [Ca10(PO4)6(OH, F)), beta-wollastonite[beta-CaSiO3] and calcium europium oxide silicate Ca2Eu8[(SiO4)6O2]. The magnetization of the sample contanining 2% Eu2O3 in weight reached 2.18 emu/g for an applied field of 10 000Oe. Hydroxyapatite layer could form on the surface of the sample while soaking for 14 days in simulated body fluid. Good bioactivity was demonstrated. So it is a potential bone repairing material as well as a hyperthemia treatment material for pateints with cancer. PMID:17899745

  7. In vivo absorption of porous apatite- and wollastonite-containing glass-ceramic.

    Science.gov (United States)

    Ohsawa, Kunitaka; Neo, Masashi; Okamoto, Tsuyoshi; Tamura, Jiro; Nakamura, Takashi

    2004-08-01

    The behavior of porous apatite- and wollastonite-containing glass-ceramic (AW) in the bone marrow cavity was investigated. Cylinders of porous AW (4 mm in diameter and 20 mm long, mean porosity of 70% and mean pore diameter of 200 microm) were implanted into the bone marrow cavity of rabbit femurs, and analyzed by chronological radiograms and by scanning electron microscopy one, three, six, and 12 months later. The pores of porous AW are interconnected and homogeneously distributed, and its compressive strength is nearly equal to that of human cancellous bone. Bone formed in the pores at the center of the material by one month and bonded to the material directly. The volume of newly formed bone in the material pores reached a peak at three months, and decreased gradually after six months. The trabecular structures of AW were gradually remodeled by newly formed bone, while AW-bone bonding was maintained during bone remodeling and material absorption. AW was absorbed continuously, and at six and 12 months the residual material corresponded to about 64 and 30% of the starting material, respectively. Porous AW may therefore be useful as an absorbable bone substitute. PMID:15477737

  8. Fabrication and Physical Evaluation of Gelatin-Coated Carbonate Apatite Foam

    Directory of Open Access Journals (Sweden)

    Kanae Hara

    2016-08-01

    Full Text Available Carbonate apatite (CO3Ap foam has gained much attention in recent years because of its ability to rapidly replace bone. However, its mechanical strength is extremely low for clinical use. In this study, to understand the potential of gelatin-reinforced CO3Ap foam for bone replacement, CO3Ap foam was reinforced with gelatin and the resulting physical characteristics were evaluated. The mechanical strength increased significantly with the gelatin reinforcement. The compressive strength of gelatin-free CO3Ap foam was 74 kPa whereas that of the gelatin-reinforced CO3Ap foam, fabricated using 30 mass % gelatin solution, was approximately 3 MPa. Heat treatment for crosslinking gelatin had little effect on the mechanical strength of the foam. The gelatin-reinforced foam did not maintain its shape when immersed in a saline solution as this promoted swelling of the gelatin; however, in the same conditions, the heat-treated gelatin-reinforced foam proved to be stable. It is concluded, therefore, that heat treatment is the key to the fabrication of stable gelatin-reinforced CO3Ap foam.

  9. Surface Structure Study of Crystal Hydroxy-Apatite from Fluorosis Enamels

    Directory of Open Access Journals (Sweden)

    Abdillah Imron Nasution

    2013-07-01

    Full Text Available Fluorosis is a condition due to ingestion of excessive amounts of fluor which can cause the change in tooth structure and strength. However, there is still lack of explanation on the surface structure of crystal hydroxyapatite that influences the microscopic characteristic of fluorosis enamel. Objectives: To investigate the surface structure of crystal hydroxy-apatite in fluorosis enamel. Materials and Methods: Determination of fluor concentration and the surface structure of normal and fluorosis enamel specimen were carried out by using Scanning Electron Microscopy/Energy Disperse X-Ray (SEM/EDX. Results: Fluor concentration of fluorosis enamel was significantly higher with increased surface roughness and porosity than normal enamel. SEM observation also showed gaps areas between enamel rods and visible aprismatic zone in some regions. Conclusion: High level of fluor concentration on fluorosis enamel indicated the subtitution of OH- by F- increasing the surface roughness of enamel surface.DOI: 10.14693/jdi.v16i3.100

  10. Prompt isothermal decay of thermoluminescence in an apatite exhibiting strong anomalous fading

    Energy Technology Data Exchange (ETDEWEB)

    Sfampa, I.K. [Aristotle University of Thessaloniki, Nuclear Physics Laboratory, 54124 Thessaloniki (Greece); Polymeris, G.S. [Aristotle University of Thessaloniki, Solid State Physics Section, 54124 Thessaloniki (Greece); Laboratory of Radiation Applications and Archaeological Dating, Department of Archaeometry and Physicochemical Measurements, ‘Athena’ R. and I. Center, Kimmeria University Campus, GR67100 Xanthi (Greece); Tsirliganis, N.C. [Laboratory of Radiation Applications and Archaeological Dating, Department of Archaeometry and Physicochemical Measurements, ‘Athena’ R. and I. Center, Kimmeria University Campus, GR67100 Xanthi (Greece); Pagonis, V. [McDaniel College, Physics Department, Westminster, MD 21157 (United States); Kitis, G., E-mail: gkitis@auth.gr [Aristotle University of Thessaloniki, Nuclear Physics Laboratory, 54124 Thessaloniki (Greece)

    2014-02-01

    Highlights: • The Isothermal TL of a material exhibiting strong AF is very peculiar. • The Isothermal TL curves are very well fitted using a newly proposed tunneling model. • The decay constants are found to be independent on temperature. • The explanation requires tunneling recombination from different excited energy levels. -- Abstract: Anomalous fading (AF) is one of the most serious drawbacks in thermoluminescence (TL) and optically stimulated luminescence (OSL) dating. In the present work the isothermal decay of TL signals from Durango apatite is studied for temperatures located on the rising part of the main TL peak. This material is known to exhibit strong AF phenomena, and its isothermal TL decay properties have not been studied previously. The experimental results show that the characteristic decay time of the isothermal signal does not depend of the temperature, and that this signal does not exhibit the strong temperature dependence expected from conventional TL kinetic theories. This is further direct experimental evidence for the possible presence of tunneling phenomena in this material. The isothermal decay curves are analyzed and discussed within the framework of conventional theories of TL, as well as within the context of a recently developed tunneling kinetic model for random distributions of electron-hole pairs in luminescent materials.

  11. Apatite formation on active nanostructured coating based on functionalized gold nanoparticles

    International Nuclear Information System (INIS)

    In this work, we developed a simple method of surface functionalization of polymer substrates to provide them with the ability to form biomimetic hydroxyapatite (HA) when incubated in synthetic body fluids (SBF). In a first step, gold nanoparticles (AuNPs) were used as surface nanostructuring units for a biocompatible polymer, poly(2-hydroxyethyl methacrylate), known to not promote biomineralization in SBF, and under physiological conditions. The treatment of AuNPs-modified substrate with mercaptosuccinic acid leads to brushes of carboxyl-ended chains self-assembled onto the gold-polymer hybrid nanosurface. The main aim of this work was to demonstrate that these multianionic nanosurfaces would induce HA formation when incubated in solutions mimicking physiologic conditions. The formation of apatite and its morphology and composition were successfully investigated by means of high resolution scanning and transmission electron microscopy with energy dispersive X-ray microanalysis, infrared spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. Emphasis was put on the nucleation of HA in areas with agglomerated carboxyl-ended functionalized nanoparticles. The results obtained in this study may unlock new applications for smart active coatings based on functionalized AuNPs, such as the induction of biomineralization.

  12. REE partitioning between apatite and melt in a peralkaline volcanic suite, Kenya Rift Valley

    Science.gov (United States)

    Macdonald, R.; Baginski, B.; Belkin, H.E.; Dzierzanowski, P.; Jezak, L.

    2009-01-01

    Electron microprobe analyses are presented for fluorapatite phenocrysts from a benmoreite-peralkaline rhyolite volcanic suite from the Kenya Rift Valley. The rocks have previously been well characterized petrographically and their crystallization conditions are reasonably well known. The REE contents in the M site increase towards the rhyolites, with a maximum britholite component of ~35 mol.%. Chondrite-normalized REE patterns are rather flat between La and Sm and then decrease towards Yb. Sodium and Fe occupy up to 1% and 4%, respectively, of the M site. The major coupled substitution is REE3+ + Si4+ ??? Ca2+ + P5+. The substitution REE3+ + Na+ ??? 2Ca2+ has been of minor importance. The relatively large Fe contents were perhaps facilitated by the low fo2 conditions of crystallization. Zoning is ubiquitous and resulted from both fractional crystallization and magma mixing. Apatites in some rhyolites are relatively Y-depleted, perhaps reflecting crystallization from melts which had precipitated zircon. Mineral/glass (melt) ratios for two rhyolites are unusually high, with maxima at Sm (762, 1123). ?? 2008 The Mineralogical Society.

  13. Equilibrium partitioning and subsequent re-distribution of halogens among apatite-biotite-amphibole assemblages from mantle-derived plutonic rocks: Complexities revealed

    Science.gov (United States)

    Teiber, Holger; Scharrer, Manuel; Marks, Michael A. W.; Arzamastsev, Andrei A.; Wenzel, Thomas; Markl, Gregor

    2015-04-01

    The concentration of halogens in apatite, biotite and amphibole is investigated for a large variety of mantle-derived plutonic rocks (gabbros, diorites, monzonites, olivine- and pyroxene-bearing monzonitic to granitic rocks, syenites, carbonatites and a phoscorite). In all rocks studied, apatite occurs as an early magmatic phase, whereas biotite and amphibole may occur either as a late magmatic phase or as late-stage, potentially hydrothermal product replacing precursor olivine, pyroxene and Fe-Ti oxides (ilmenite and magnetite). Based on electron microprobe analyses for F and Cl and detailed textural observations, we test existing models of halogen partitioning between apatite and biotite. Bromine concentration data for apatite, biotite and amphibole are used to further refine our understanding of the geochemical similarities and differences between Cl and Br during magmatic and hydrothermal processes. Our data suggests that F and Cl contents in apatite, biotite and amphibole can indeed be useful monitors of the halogen systematics in magmas, but they may also be subject to post-magmatic changes to variable extents. The relatively small radius and compatible F cation seems to be less prone to post-magmatic alteration and is likely to best reflect the original magmatic halogen abundances - especially in apatite. However, the larger and probably more incompatible Cl anion, is more easily re-mobilized as reflected by strong redistribution of Cl in biotite and amphibole which have been clearly overprinted by hydrothermal fluids. In certain cases, the ability of halogens to re-distribute themselves after magmatic equilibrium partitioning (as emphasized by our data) suggests that observed partitioning (especially between apatite and biotite) may also be used as a very sensitive indicator for post-magmatic hydrothermal processes.

  14. Stability and heavy metal distribution of soil aggregates affected by application of apatite, lime, and charcoal.

    Science.gov (United States)

    Cui, Hongbiao; Ma, Kaiqiang; Fan, Yuchao; Peng, Xinhua; Mao, Jingdong; Zhou, Dongmei; Zhang, Zhongbin; Zhou, Jing

    2016-06-01

    Only a few studies have been reported on the stability and heavy metal distribution of soil aggregates after soil treatments to reduce the availability of heavy metals. In this study, apatite (22.3 t ha(-1)), lime (4.45 t ha(-1)), and charcoal (66.8 t ha(-1)) were applied to a heavy metal-contaminated soil for 4 years. The stability and heavy metal distribution of soil aggregates were investigated by dry and wet sieving. No significant change in the dry mean weight diameter was observed in any treatments. Compared with the control, three-amendment treatments significantly increased the wet mean weight diameter, but only charcoal treatment significantly increased the wet aggregate stability. The soil treatments increased the content of soil organic carbon, and the fraction 0.25-2 mm contained the highest content of soil organic carbon. Amendments' application slightly increased soil total Cu and Cd, but decreased the concentrations of CaCl2 -extractable Cu and Cd except for the fraction 2 and 0.25-2 mm contained the highest concentrations of CaCl2-extractable Cu and Cd, accounted for about 74.5-86.8 % of CaCl2-extractable Cu and Cd in soil. The results indicated that amendments' application increased the wet soil aggregate stability and decreased the available Cu and Cd. The distribution of available heavy metals in wet soil aggregates was not controlled by soil aggregate stability, but possibly by soil organic carbon. PMID:26893180

  15. The effects of silver, silicon-containing apatite towards bacteria and cell responses

    International Nuclear Information System (INIS)

    An integrated approach is proposed to incorporate silicon and silver into hydroxyapatite (HA) to enhance the biological response and reduce implant-related infection in bone substitutes. This study examined the responses of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria to silver, silicon-containing apatite (Ag,Si-HA). Scanning electron microscopy images revealed significant reduction in adherence of S. aureus and E. coli bacteria on Ag,Si-HA as compared to HA. The antibacterial property of Ag,Si-HA was shown from a 7-log reduction of S. aureus population in the test solution and on the sample's surface as compared to HA at day 7. Rapid inhibition of the adherent bacteria suggested that the antibacterial action of Ag incorporated in Ag,Si-HA could be attributed to the Ag+ ions on the crystal surface rather than the released Ag+ ions. Presence of Ag may influence the biological response of HA and as such, the long-term interaction between human adipose-derived mesenchymal stem cells and Ag,Si-HA was evaluated in-vitro. An alamarBlue™ assay showed higher cell proliferation for Ag,Si-HA as compared to HA from day 3 onwards. Immunofluorescence staining revealed well-spread actin cytoskeletons on Ag,Si-HA. In addition, signs of extracellular matrix secretion and biomineralization were observed on Ag,Si-HA at day 14 onwards. Results demonstrated enhanced bone differentiation on Ag,Si-HA, as indicated by a higher level of protein expressions (type 1 collagen and osteocalcin) from day 14 to 21. Therefore, the incorporation of Ag and Si complement each other by endowing HA with antibacterial property, and concurrently promoting biological performance of the cells. (paper)

  16. Synthesis of sodium caseinate-calcium carbonate microspheres and their mineralization to bone-like apatite

    Science.gov (United States)

    Xu, Zhewu; Liang, Guobin; Jin, Lin; Wang, Zhenling; Xing, Chao; Jiange, Qing; Zhang, Zhiguang

    2014-06-01

    Phosphoproteins can induce and stabilize calcium carbonate (CaCO3) vaterite, which has desirable features for high reactivity. The purpose of this study was to synthesize bioactive CaCO3 microspheres for bone regeneration. Sodium caseinate (NaCas)-containing CaCO3 microspheres, with the crystal phase of vaterite, were synthesized by fast precipitation in an aqueous solution of CaCl2, Na2CO3, and 2 mg/mL of NaCas. The uniform microspheres exhibited rougher surfaces and lower negative charges than CaCO3 particles without NaCas addition. Fourier-transform infrared spectroscopy (FT-IR) of the microspheres showed characteristic peaks or bands corresponding to phosphate and hydroxyl groups. Thermogravimetric analysis (TGA) curves exhibited approximately 5% weight loss below 600 °C due to the decomposition of NaCas. Scanning electron microscope (SEM) images showed lath-like hydroxyapatite (HAp) on the surface after soaking in simulated body fluid (SBF) at 37 °C for 5 and 10 days. Energy dispersive X-ray spectrometry (EDS) revealed that the agglomerates were composed of Ca, C, O, P, Na, and Mg elements, and the Ca/P ratios ranged from 1.53 to 1.56. X-ray diffraction (XRD) patterns exhibited peaks characteristic of hydroxyapatite. The results of this study demonstrated that the addition of NaCas induced the formation of vaterite microspheres which possesses an enhanced apatite formation after soaking in SBF at 37 °C for 5 and 10 days. These NaCas-CaCO3 microspheres may be a potential biomaterial for bone regeneration.

  17. Biological Behavior of Osteoblast Cell and Apatite Forming Ability of the Surface Modified Ti Alloys.

    Science.gov (United States)

    Zhao, Jingming; Hwang, K H; Choi, W S; Shin, S J; Lee, J K

    2016-02-01

    Titanium as one kind of biomaterials comes in direct contact with the body, making evaluation of biocompatibility an important aspect to biomaterials development. Surface chemistry of titanium plays an important role in osseointegration. Different surface modification alters the surface chemistry and result in different biological response. In this study, three kinds of mixed acid solutions were used to treat Ti specimens to induce Ca-P formation. Following a strong mixed acid activation process, Ca-P coating successfully formed on the Ti surfaces in simulated body fluid. Strong mixed acid increased the roughness of the metal surface, because the porous and rough surface allows better adhesion between Ca-P coatings and substrates. After modification of titanium surface by mixed acidic solution and subsequently H2O2/HCL treatment evaluation of biocompatibility was conducted from hydroxyapatite formation by biomimetic process and cell viability on modified titanium surface. Nano-scale modification of titanium surfaces can alter cellular and tissue responses, which may benefit osseointegration and dental implant therapy. Results from this study indicated that surface treatment methods affect the surface morphology, type of TiO2 layer formed and subsequent apatite deposition and biological responses. The thermo scientific alamarblue cell viability assay reagent is used to quantitatively measure the viability of mammalian cell lines, bacteria and fungi by incorporating a rapid, sensitive and reliable fluorometric/colorimetric growth indicator, without any toxic and side effect to cell line. In addition, mixed acid treatment uses a lower temperature and shorter time period than widely used alkali treatment. PMID:27433617

  18. Raman spectroscopy study of damage induced in fluor-apatite by swift heavy ion irradiations

    International Nuclear Information System (INIS)

    Raman spectroscopy was used to study the radiation damage of fluor-apatite single crystals and sinters. Krypton and iodine ion irradiations were performed at high energies (∼ 1 MeV amu-1) for fluences ranging between 1 * 1011 and 5 * 1013 cm-2. Evolution of the symmetric stretching mode of the PO43- tetrahedral building blocks (strongest Raman mode observed at 965 cm-1) versus ion fluence was investigated. After irradiation, this peak decreases in intensity and a second broader peak appears at lower wavenumber. The well-resolved peak has been assigned to the crystalline phase, and the broader one to the amorphous phase. The integrated intensity ratios of these two peaks versus fluence are in good agreement with the damage fractions determined by X-ray diffraction (XRD). Fits of the amorphous fraction versus fluence show that the amorphization mechanisms is dominated by a single-impact process for iodine ions and by a double-impact process for krypton ions in the case of single crystals and sinters. For both irradiations, complete amorphization could not be obtained. The amorphous fraction saturates at a maximum value of 88% for sinters and 72% for single crystals. This is attributed to a recrystallization effect which is more important in single crystals than in sinters. For both types of samples, the crystalline peak shifts slightly to a lower wavenumber with fluence, and then shifts back to its initial value for an amorphous fraction larger than 60%. This feature is attributed to a stress relaxation, as shown in the XRD data, which is accompanied by a decrease of the crystalline peak full-width at half-maximum. (authors)

  19. Phanerozoic surface history of southern Peninsular India from apatite (U-Th-Sm)/He data

    Science.gov (United States)

    Mandal, Sanjay Kumar; Fellin, Maria Giuditta; Burg, Jean-Pierre; Maden, Colin

    2015-10-01

    Quantifying bedrock cooling history is crucial for understanding the long-term landform evolution across passive margins and its control onto the sediment routing system. To constrain the low-temperature cooling history and its relationships to the Phanerozoic tectonic events of southern Peninsular India, we present new apatite (U-Th-Sm)/He (AHe) analyses of 39 Precambrian basement samples. The new AHe ages range from 38.1 ± 6.8 to 364.2 ± 44.6 Ma: they are younger than 50 Ma in the Palghat Gap region and older than 200 Ma in the interior of the Deccan Plateau. Thermal modeling based on AHe data indicates enhanced cooling and exhumation in the interior of the Deccan Plateau by Permian-Triassic times followed by gradual cooling up to the Present. This discrete episode of Permian-Triassic cooling is associated with continental extension that preceded the Early Jurassic breakup of Gondwana. Bedrock cooling and exhumation on the southeastern and southern limits of the Deccan Plateau was likely accomplished by Late Cretaceous drainage reorganization. The distribution of old (>200 Ma) AHe ages over the >2600 m high Nilgiri Plateau reflects very low erosion/exhumation rates and adds to examples of long-lived postorogenic topography. The relatively younger AHe ages from the ˜30 km wide low mountain pass (Palghat Gap) within the Western Ghat Mountains attest for intense Cenozoic erosion likely facilitated by the erodible lithological backbone of the Neoproterozoic shear zone. AHe ages across the western coastal plain challenge the widely hold notion of ˜3 km of post-breakup isostatic rebound in response to erosion of the margin. Instead, the new AHe data are more compatible with less than 1-1.5 km of crustal denudation along the coastal strip.

  20. The KTB apatite fission-track profiles: Building on a firm foundation?

    Science.gov (United States)

    Wauschkuhn, B.; Jonckheere, R.; Ratschbacher, L.

    2015-10-01

    Deep boreholes serve as natural laboratories for testing thermochronometers under geological conditions. The Kontinentale Tiefbohrung (KTB) is an interesting candidate because the geological evidence suggests that approximate isothermal holding since the last documented exhumation in the Late Cretaceous to Palaeocene is a reasonable assumption for the thermal histories of the KTB samples. We report 30 new apatite fission-track ages and 50 new mean confined track lengths determined on cores from the 4 km deep pilot hole. The ϕ- and ζ-external detector ages are consistent with the population ages from earlier studies and together define a clear age profile. The mean track lengths from this and earlier studies reveal the effects of experimental factors. The measured age and length profiles are compared with the predictions of 24 annealing models for isothermal holding. There are clear discrepancies between the measured and calculated profiles. Down to 1.5 km depth, the measured mean track lengths are shorter than the predicted. The balance of methodological evidence indicates that this is due to seasoning, i.e., a shortening of the fossil confined tracks without attendant age reduction. From 2.5 to 4.0 km depth, the mean track lengths are longer than the predictions. This suggests that the bias model that weights the probabilities of observing tracks of different length and which is based on experiments relating surface track densities to mean track lengths is not appropriate for confined tracks. Experimental and methodological factors are sometimes difficult to disentangle, but present a sufficient margin for there to be no need to go against the independent geological evidence. Unknown geological events cannot be ruled out but their existence cannot be inferred from the fission-track data alone, much less can the nature or magnitude of such events be specified.

  1. Multikinetic modeling for tectonic evolution of Hefei Basin by apatite fission-track (AFT) analyses

    International Nuclear Information System (INIS)

    Apatite fission-track (AFT) analyses of Jurassic sandstones from Yuantongshan Formation (J2y) at Dazitang area of Feixi County in the central part of Hefei Basin suggested that its fission-track (FT)age is (32.5±2.4)Ma (the average of 22 grains) which is apparently younger than the strata age (176∼168 Ma), their mean confined track length is (12.43±0.18)μm (the average of 126 tracks length), and displays a unimodal distribution. The modeling thermal history can be divided into five stages: 176∼152 Ma before present with the cooling rate of -21.4 degree C per million years, 152∼85 Ma before present with the cooling rate -0.1 degree C per million years, 85∼32 Ma before present with the cooling rate 1.4 degree C per million years, 32∼10 Ma before present with the cooling rate 1.6 degree C per million years, and 10 Ma to present with the cooling rate 5.0 degree C per million years. Five stages are corresponded respectively to the rapid subsidence and heating of sediment, the stable tectonic and thermal evolution, rapid basin uplifting and cooling. The rapid subsidence of sediment (176∼152 Ma) means that Hefei Basin is controlled by compression of Late Dabie Orogeny and subsided rapidly. The stage of stable sedimentary tectonic evolution (152∼85 Ma) shows that Hefei Basin is mainly controlled by dome extension and magmatism of Dabie Orogeny. The cooling stage of (85∼25 Ma) is controlled by the strike-slipping of Tanlu Fault and regional extension. The last stage (since 25 Ma) is characterized by compression, uplift and rapid erosion of Hefei Basin. (authors)

  2. Strategies for the optimisation of the oxide ion conductivities of apatite-type germanates

    Energy Technology Data Exchange (ETDEWEB)

    Orera, A.; Slater, P.R. [School of Chemistry, University of Birmingham, Birmingham (United Kingdom); Baikie, T. [School of Materials Science and Engineering, Nanyang Technological University, Singapore (Singapore); Panchmatia, P.; Islam, M.S. [Department of Chemistry, University of Bath, Bath (United Kingdom); White, T.J. [Centre for Advanced Microscopy, Australian National University, Canberra ACT 2601 (Australia); Hanna, J.; Smith, M.E. [Department of Physics, University of Warwick, Coventry (United Kingdom); Kendrick, E. [Chemical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

    2011-02-15

    Recently, apatite-type germanates La{sub 9.33+x}Ge{sub 6}O{sub 26+3x/2} have attracted considerable interest due to their high oxide ion conductivities. Research has shown that the key defects are oxide ion interstitials which lead to the conversion of some of the GeO{sub 4} units to GeO{sub 5}. Consequently there has been a large interest in the preparation of high oxygen excess samples with high defect concentration. This strategy, however, leads to a reduction in symmetry from hexagonal to triclinic for x> 0.4, and consequently to reduced oxide ion conductivity at low temperatures. We present doping strategies to stabilise the hexagonal lattice, while maintaining high oxygen content. In particular, partial substitution of La by smaller rare earths (Y,Yb) is shown to be successful in preparing x = 0.67 samples with hexagonal symmetry and hence high conductivities. In addition, doping on the Ge site with Ti, Nb or W, has been shown to be similarly successful, leading to very high oxygen contents for W doping, e.g. La{sub 10}Ge{sub 5.5}W{sub 0.5}O{sub 27.5}. In the case of Ti doping, however, there was some evidence for trapping of the interstitial oxide ions around the Ti. Preliminary results on the effect of similar doping strategies on Pr, Nd germanates (Pr/Nd){sub 9.33+x}Ge{sub 6}O{sub 26+3x/2}, are also discussed. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Study of the auto-irradiation effects in apatites structure materials; Etude des effets d'auto-irradiation dans des materiaux a structure apatitique

    Energy Technology Data Exchange (ETDEWEB)

    Soulet, St

    2000-11-15

    The incorporation of an actinide in a material puts it to the action of an alpha particle, of some MeV always followed by the recoil of the residual nucleus. This last ones, with an energy of about a hundred of keV produces the greatest part of the irradiation damages. The study of the natural analogues has allowed to identify the fluoro-apatites which have a high amount of phosphates groups, as potential actinides conditioning matrices. Former works, simulating the alpha decay in the monocrystalline phospho-calcic fluoro-apatite have revealed an exfoliation phenomenon and an annealing of the defects which are formed by the recoil nuclei by the helium ions. This work has shown that the exfoliation can not be produced on polycrystalline apatitic materials (phospho-calcic fluoro-apatite and fluoro-apatite with one silicate) probably on account of the removal of helium outside the grains and by the diffusion of helium inside the grain boundaries. On the other hand, these helium removal ways decrease the chemical resistance of the fluoro-apatite. In the same way, the dissolution velocity of the apatite is strongly increased above the damage threshold corresponding to the percolation of the isolated defects and especially in the case of total amorphization. Concerning the effect of the recoil and annealing nuclei by the alpha particles, an original study method including the use of a transmission electron microscope coupled with a ions implanter has been carried out. This device has allowed to make irradiations simulating the alpha decay and to follow in situ the evolution of polycrystalline samples disorder. It has been shown that for all the solid solution of phospho-silicated fluoro-apatites, the amorphization is produced directly in series. In the same way, on account of this technique, the efficiency of the annealing by alpha has been measured on different apatite compositions. The main result shows that the efficiency of the annealing by alpha in the fluoro-apatite

  4. Increase of apatite dissolution rate by Scots pine roots associated or not with Burkholderia glathei PML1(12)Rp in open-system flow microcosms

    Science.gov (United States)

    Calvaruso, Christophe; Turpault, Marie-Pierre; Frey-Klett, Pascale; Uroz, Stéphane; Pierret, Marie-Claire; Tosheva, Zornitza; Kies, Antoine

    2013-04-01

    The release of nutritive elements through apatite dissolution represents the main source of phosphorus, calcium, and several micronutrients (e.g., Zn, Cu) for organisms in non-fertilized forest ecosystems. The aim of this study was to quantify, for the first time, the dissolution rate of apatite grains by tree roots that were or were not associated with a mineral weathering bacterial strain, and by various acids known to be produced by tree roots and soil bacterial strains in open-system flow microcosms. In addition, we explored whether the mobilization of trace elements (including rare earth elements) upon apatite dissolution was affected by the presence of trees and associated microorganisms. The dissolution rate of apatite by Scots pine plants that were or were not inoculated with the strain Burkholderia glathei PML1(12)Rp, and by inorganic (nitric) and organic (citric, oxalic and gluconic) acids at pH 5.5, 4.8, 3.8, 3.5, 3.0, and 2.0 was monitored in two controlled experiments: "plant-bacteria interaction" and "inorganic and organic acids". Analyses of the outlet solutions in the "plant-bacteria interaction" experiment showed that Scots pine roots and B. glathei PML1(12)Rp produced protons and organic acids such as gluconate, oxalate, acetate, and lactate. The weathering budget calculation revealed that Scots pines (with or without PML1(12)Rp) significantly increased (factor > 10) the release of Ca, P, As, Sr, Zn, U, Y, and rare earth elements such as Ce, La, Nd from apatite, compared to control abiotic treatment. Scanning electron microscopy observation confirmed traces of apatite dissolution in contact of roots. Most dissolved elements were taken up by Scots pine roots, i.e., approximately 50% of Ca, 70% of P, 30% of As, 70% of Sr, 90% of Zn, and 100% of U, Y, and rare earth elements. Interestingly, no significant additional effect due to the bacterial strain PML1(12)Rp on apatite dissolution and Scots pine nutrition and growth was observed. The "inorganic

  5. Apatite trace element and halogen compositions as petrogenetic-metallogenic indicators: Examples from four granite plutons in the Sanjiang region, SW China

    Science.gov (United States)

    Pan, Li-Chuan; Hu, Rui-Zhong; Wang, Xin-Song; Bi, Xian-Wu; Zhu, Jing-Jing; Li, Chusi

    2016-06-01

    The abundances of trace elements including Sr, Ga and rare earth elements (REE) and halogens in apatite crystals from four intermediate-felsic plutons in the Zhongdian terrane in the Sanjiang region have been determined using electron microprobe and laser ablation inductively coupled plasma mass spectrometry to evaluate the potential of apatite as a petrogenic-metallogenic indicator. The selected plutons include one that is not mineralized (the Triassic Xiuwacu pluton, or the TXWC pluton), one that hosts a porphyry-type Cu deposit (the Pulang pluton, or the PL pluton), one that hosts a porphyry-type Mo deposit (the Tongchanggou pluton, or the TCG pluton), and one that hosts a vein-type Mo deposit (the Cretaceous Xiuwacu pluton, or the CXWC pluton). Except for the CXWC pluton, the other three plutons have adakite-like trace element signatures in whole rocks. The results from this study show that REE, Sr and halogens in apatite can be used to track magma compositions, oxidation states and crystallization history. Apatite crystals from the adakite-like plutons are characterized by much higher Sr/Y and δEu than the non-adakite-type pluton. This means that apatite, which is not susceptible to alteration, is a useful tool for identifying the adakite-like plutons that no longer preserve the initial Sr/Y ratios in whole rocks due to weathering and hydrothermal alteration. Based on apatite Ga contents and δEu values, it is inferred that the parental magmas for the two adakite-like plutons containing porphyry-type Cu and Mo mineralization are more oxidized than that for the non-adakite-type pluton containing vein-type Mo mineralization. Apatite crystals from the vein-type Mo deposit have much lower Cl/F ratios than those from the porphyry-type Cu and Mo deposits. Apatite crystals from the adakite-like pluton without Cu or Mo mineralization is characterized by much lower Cl/F ratios than those from the adakite-like plutons that host the porphyry-type Cu and Mo deposits. The

  6. Project Work Plan: Sequestration of Strontium-90 Subsurface Contamination in the Hanford 100-N Area by Surface Infiltration of an Apatite Solution

    Energy Technology Data Exchange (ETDEWEB)

    Szecsody, Jim E.

    2006-04-30

    We propose to develop an infiltration strategy that defines the precipitation rate of an apatite-forming solution and Sr-90 sequestration processes under variably saturated (low water content) conditions. We will develop this understanding through small-scale column studies, intermediate-scale two-dimensional (2-D) experiments, and numerical modeling to quantify individual and coupled processes associated with apatite formation and Sr-90 transport during and after infiltration of the Ca-citrate-PO4 solution. Development of capabilities to simulate these coupled biogeochemical processes during both injection and infiltration will be used to determine the most cost-effective means to emplace an in situ apatite barrier with a longevity of 300 years to permanently sequester Sr-90 until it decays. Biogeochemical processes that will be investigated are citrate biodegradation and apatite precipitation rates at varying water contents as a function of water content. Coupled processes that will be investigated include the influence of apatite precipitation (which occupies pore space) on the hydraulic and transport properties of the porous media during infiltration.

  7. Two high terbium content apatites: Tb5Si2BO13 and Tb4.66Si3O13

    International Nuclear Information System (INIS)

    Graphical abstract: Two terbium apatites Tb5Si2BO13 and Tb4.66Si3O13 may be promising magneto-optical materials due to their high terbium content. - Highlights: • Two terbium apatite Tb5Si2BO13 and Tb4.66Si3O13 crystals were grown by flux method. • Structures of both compounds were determined via single-crystal diffraction. • Both compounds show paramagnetic behaviours down to 2 K. • Both compounds may be promising magneto-optical materials due to high Tb3+ contents. - Abstract: Two high content terbium apatites, Tb5Si2BO13 and Tb4.66Si3O13, have been successfully synthesized by sol-gel method and have been crystallized from high temperature flux. Their structures were identified by single crystal X-ray diffraction and were found to belong to the hexagonal system with space group P63/m and unit cell parameters of a = 9.2569(10) Å, c = 6.8297(12) Å and Z = 2 for Tb5Si2BO13 and a = 9.493(4) Å, c = 6.852(5) Å and Z = 2 for Tb4.66Si3O13, respectively. The diffuse optical reflection spectra clearly indicate that the two crystals have good optical transparency in the range of 500-1500 nm. The paramagnetic behaviours of Tb5Si2BO13 and Tb4.66Si3O13 from 2 K to 300 K are confirmed by magnetic susceptibility measurements. In comparison with other known Tb containing magneto-optical (MO) glass and crystals, Tb5Si2BO13 and Tb4.66Si3O13 are found to be promising magneto-optical materials in the visible-near IR range due to the high Tb3+ concentrations in both compounds

  8. Enhanced ionic conductivity of apatite-type lanthanum silicate electrolyte for IT-SOFCs through copper doping

    Science.gov (United States)

    Ding, Xifeng; Hua, Guixiang; Ding, Dong; Zhu, Wenliang; Wang, Hongjin

    2016-02-01

    Apatite-type Lanthanum silicate (LSO) is among the most promising electrolyte for intermediate temperature solid oxide fuel cells (IT-SOFCs) owing to the high conductivity and low activation energy at lower temperature than traditional doped-zirconia electrolyte. The ionic conductivity as well as the sintering density of lanthanum silicate oxy-apatite, La10Si6-xCuxO27-δ (LSCO, 0 ≤ x ≤ 2), was effectively enhanced through a small amount of doped copper. The phase composition, relative density, ionic conductivity and thermal expansion behavior of La10Si6-xCuxO27-δ was systematically investigated by X-ray diffraction (XRD), Archimedes' drainage method, scanning electron microscope (SEM), electrochemical impedance spectra (EIS) and thermal dilatometer techniques. With increasing copper doping content, the ionic conductivity of La10Si6-xCuxO27-δincreased, reaching a maximum of 4.8 × 10-2 S cm-1 at 800 °C for x = 1.5. The improved ionic conductivity could be primarily associated with the enhanced grain conductivity. The power output performance of NiO-LSCO/LSCO/LSCF single cell was superior to that obtained on NiO-LSO/LSO/LSCF at different temperatures using hydrogen as fuel and oxygen as oxidant, which could be attributed to the enhanced oxygen ionic conductivity as well as the sintering density for the copped doped lanthanum silicate. In conclusion, the apatite La10Si4.5Cu1.5O25.5 is a promising candidate electrolyte for IT-SOFCs.

  9. Apatite- and monazite-bearing glass-crystal composites for the immobilization of low-level nuclear and hazardous wastes

    International Nuclear Information System (INIS)

    This study demonstrates that glass-crystal composite waste forms can be produced from waste streams containing high proportions of phosphorus, transition metals, and/or halides. The crystalline phases produced in crucible-scale melts include apatite, monazite, spinels, and a Zr-Si-Fe-Ti phase. These phases readily incorporated radionuclide and toxic metals into their crystal structures, while corrosion tests have demonstrated that glass-crystal composites can be up to 300-fold more durable than simulated high-level nuclear waste glasses, such as SRL 202U

  10. Luminescence of Eu(III), Pr(III) and Sm(III) in carbonate-fluor-apatite

    International Nuclear Information System (INIS)

    The purpose of this work was identification of luminescent lines occurring in natural carbonate-fluor-apatite (francolite) mineral. For identification of several rare earth ions occurring in natural francolite, the luminescence of rare earth ions was extensively studied in artificial mineral consisting of pure francolite (not containing rare earth) of the composition Ca5(PO4)3(F,O):Ca5(PO4)3CO3 activated with Pr, Eu and Sm ions and then compared with the luminescence features observed in natural mineral. (author)

  11. Abundance and distribution of uranium and thorium in zircon, sphene, apatite, epidote, and monazite in granitic rocks

    Science.gov (United States)

    Hurley, Patrick M.; Fairbairn, Harold W.

    1956-01-01

    Analyses were made of uranium and thorium in ziircon, sphene, apatite, epidote, and monazite separated as accessory minerals from samples of granitic rock from widely scattered localities to indicate the abundance and distribution of these two elements among the five mineral phases.  For any pair of mineral phases the distribution ratio remains within the same order of magnitude over the different rocks tested, although the variability of the data is such that only wide departures from constancy could be ascertained.  Such gross differences have not been found. 

  12. Exhumations- und Hebungsgeschichte der zentralen Anden in Südbolivien (21°S) durch Spaltspur-Thermochronologie an Apatit

    OpenAIRE

    Ege, Harald

    2010-01-01

    The Tertiary formation of the Altiplano-Puna plateau at the active continental margin of South America resulted in the doubling of the crust and surface uplift by about 4000 m. The aim of this study is to reconstruct the Tertiary cooling and exhumation history by apatite fission track thermochronology (AFT) and hence to characterise the processes which produced plateau uplift. The study area follows a transect at 21°S in Southern Bolivia across the plateau and the eastern flank of the Andes. ...

  13. Characteristics, apatite-forming ability and corrosion resistance of NiTi surface modified by AC anodization

    International Nuclear Information System (INIS)

    NiTi samples were anodized in the non-sparking regime using AC voltage in a solution containing calcium and phosphate ions (solution Ca-P). The as-anodized samples were subsequently treated hydrothermally in water (sample A-W-NiTi) or in solution Ca-P (sample A-CaP-NiTi). Thin-film X-ray diffractometry (TF-XRD) analysis confirmed the existence of anatase in the hydrothermally treated samples, but not in the as-anodized sample, while hydroxyapatite (HA) was detected only in sample A-CaP-NiTi. Cross-sectional micrograph by scanning-electron microscopy (SEM) revealed that the thickness of the modified surface layer formed on sample A-CaP-NiTi was ∼200 nm. X-ray photoelectron spectroscopy (XPS) analysis showed that the Ni concentrations at the surface of sample A-W-NiTi and sample A-CaP-NiTi were in the order of 0.4 and 0.3 at.%, respectively, which were about an order of magnitude lower than that for bare NiTi. Both Ca and P were present in the surface layer on as-anodized NiTi and sample A-CaP-NiTi, but negligible on sample A-W-NiTi, as determined from XPS composition depth profiling. Immersion tests in a conventional simulated body fluid (SBF) of the Kokubo type to study apatite-forming ability showed that growth of apatite was induced on A-W-NiTi and much more abundantly on A-CaP-NiTi, but not on bare NiTi and as-anodized NiTi, suggesting that the presence of anatase and HA is favorable for apatite growth. The apatite-forming ability of the samples in the present study may be ranked in ascending order as: bare NiTi < As-anodized NiTi < A-W-NiTi < A-CaP-NiTi. Polarization tests in Hanks' solution recorded significant increase in corrosion resistance due to anodization and further increase was obtained via hydrothermal treatment. The present study thus shows that anodization followed by hydrothermal treatment is a simple method to form a potentially bioactive and at the same time corrosion resistant surface layer on NiTi

  14. Model Evaluation the Effect of Size, Shape and Surface Condition of Apatite Nanocrystals on the Deviation of Ca / P ratio from stoichiometric

    Directory of Open Access Journals (Sweden)

    S.N. Danilchenko

    2014-04-01

    Full Text Available The causes of Са / Р ratio deviation in biological apatites from stoichiometric one were discussed. By the simple model evaluation Са / Р ratio was shown to deviate from stoichiometric one because of small sizes of crystals, and peculiarities in chemical composition of their facets. Also size effect is noted to be unsufficient for explanation of wide variations of Са / Р ratio in biological apatites. It proves the significant contribution of lattice isovalent and heterovalent substitution into variability of Са / Р ratio. The problem of revealing the predominant causes of Са / Р deviation from stoichiometric one and estimation of their relative contribution is related to determination of the functional role of the structural imperfections in biological apatites of different origin.

  15. Study of damage and helium diffusion in fluoro-apatites; Etude de l'endommagement et de la diffusion de l'helium dans des fluoroapatites

    Energy Technology Data Exchange (ETDEWEB)

    Miro, S

    2004-12-15

    This work lies within the scope of the study of the radionuclides containment matrices. The choice of the fluoro-apatites as potential matrices of containment was suggested by the notable properties of these latter (thermal and chemical stability even under radioactive radiation). By irradiations with heavy ions and a helium implantation we simulated the effects related to the alpha radioactivity and to the spontaneous nuclear fission of the radionuclides. Thanks to the study of Durango fluoro-apatite single crystals and fluoro-apatite sintered ceramics, we evidenced that the damage fraction as well as the unit cell deformations increase with the electronic energy loss and with the substitution. These effects are followed at high fluences by a phenomenon of re-crystallization. The study of the helium diffusion points out that the thermal diffusion process improves with the substitution and strongly increases with heavy ions irradiation. (author)

  16. Apatite Fission-Track Analysis of the Middle Jurassic Todos Santos Formation from Chiapas, Mexico.

    Science.gov (United States)

    Abdullin, Fanis; Solé, Jesús; Shchepetilnikova, Valentina; Solari, Luigi; Ortega-Obregón, Carlos

    2014-05-01

    The Sierra de Chiapas (SCH), located in the south of Mexico, is a complex geological province that can be divided on four different lithological or tectonic areas: (1) the Chiapas Massif Complex (CMC); (2) the Central Depression; (3) the Strike-slip Fault Province, and (4) the Chiapas Fold-and-thrust Belt. The CMC mostly consists of Permian granitoids and meta-granitoids, and represents the basement of the SCH. During the Jurassic period red beds and salt were deposited on this territory, related to the main pulse of rifting and opening of the Gulf of Mexico. Most of the Cretaceous stratigraphy contains limestones and dolomites deposited on a marine platform setting during the postrift stage of the Gulf of Mexico rift. During the Cenozoic Era took place the major clastic sedimentation along the SCH. According the published low-temperature geochronology data (Witt et al., 2012), SCH has three main phases of thermo-tectonic history: (1) slow exhumation between 35 and 25 Ma, that affected mainly the basement (CMC) and is probably related to the migration of the Chortís block; (2) fast exhumation during the Middle-Late Miocene caused by strike-slip deformation that affects almost all Chiapas territory; (3) period of rapid cooling from 6 to 5 Ma, that affects the Chiapas Fold-and-thrust Belt, coincident with the landward migration of the Caribbean-North America plate boundaries. The two last events were the most significant on the formation of the present-day topography of the SCH. However, the stratigraphy of the SCH shows traces of the existence of earlier tectonic events. This study presents preliminary results of apatite fission-track (AFT) dating of sandstones from the Todos Santos Formation (Middle Jurassic). The analyses are performed with in situ uranium determination using LA-ICP-MS (e.g., Hasebe et al., 2004). The AFT data indicate that this Formation has suffered high-grade diagenesis (probably over 150 ºC) and the obtained cooling ages, about 70-60 Ma

  17. Application of carbonated apatite coating on a Ti substrate by aqueous spray method

    Energy Technology Data Exchange (ETDEWEB)

    Mochizuki, Chihiro; Hara, Hiroki [Division of Liberal Arts, Kogakuin University, 2665-1, Nakano, Hachioji, Tokyo 192-0015 (Japan); Takano, Ichiro [Department of Electrical Engineering, Kogakuin University, 2665-1, Nakano, Hachioji, Tokyo 192-0015 (Japan); Hayakawa, Tohru [Department of Dental Engineering, Tsurumi University School of Dental Medicine, Tsurumi, Yokohama City, Kanagawa 230-8501 (Japan); Sato, Mitsunobu, E-mail: lccsato@cc.kogakuin.ac.jp [Division of Liberal Arts, Kogakuin University, 2665-1, Nakano, Hachioji, Tokyo 192-0015 (Japan)

    2013-03-01

    The fabrication and characterization of a carbonate-containing apatite film deposited on a Ti plate via an aqueous spray method is described. The mist of the spray solution emitted from a perpendicularly oriented airbrush was made to strike a warmed Ti substrate. The thicknesses of the sprayed film and those heat-treated at 400 Degree-Sign C-700 Degree-Sign C under Ar gas flow were in the range 1.21-1.40 {mu}m. The results of elemental analyses and Fourier transform infrared spectroscopy of the powders that were mechanically collected from the surface of the sprayed film suggest that the film was Ca{sub 10}(PO{sub 4})6(CO{sub 3}) {center_dot} 2CO{sub 2} {center_dot} 3H{sub 2}O. The presence of the carbonate ion and the lattice CO{sub 2} molecule was confirmed via the aforementioned analyses; the finding was also consistent with the X-ray diffraction patterns of the films and the chemical identity of the sprayed and heat-treated films that were measured using X-ray photoelectron spectroscopy. The sprayed film comprises a characteristic network structure, which contains round particles within the networks, as was observed by field-emission scanning electron microscopy. A scratch test indicated that the shear stress of the sprayed film (21 MPa) significantly improved to 40 and > 133 MPa after heat-treatment at 600 Degree-Sign C and 700 Degree-Sign C, respectively, under Ar gas flow for 10 min. - Highlights: Black-Right-Pointing-Pointer CO{sub 2} inserted CA films were fabricated on a Ti plate by the aqueous spray method. Black-Right-Pointing-Pointer The characteristic network structure of the sprayed film was clarified by FE-SEM. Black-Right-Pointing-Pointer Ca{sub 10}(PO{sub 4})6(CO{sub 3}) {center_dot} 2CO{sub 2} {center_dot} 3H{sub 2}O film with a thickness of ca. 1 {mu}m could be deposited. Black-Right-Pointing-Pointer A well-adhered film with shear stress of 21 MPa was obtained at low temperatures. Black-Right-Pointing-Pointer A stable solution for VOC

  18. Application of carbonated apatite coating on a Ti substrate by aqueous spray method

    International Nuclear Information System (INIS)

    The fabrication and characterization of a carbonate-containing apatite film deposited on a Ti plate via an aqueous spray method is described. The mist of the spray solution emitted from a perpendicularly oriented airbrush was made to strike a warmed Ti substrate. The thicknesses of the sprayed film and those heat-treated at 400 °C–700 °C under Ar gas flow were in the range 1.21–1.40 μm. The results of elemental analyses and Fourier transform infrared spectroscopy of the powders that were mechanically collected from the surface of the sprayed film suggest that the film was Ca10(PO4)6(CO3) · 2CO2 · 3H2O. The presence of the carbonate ion and the lattice CO2 molecule was confirmed via the aforementioned analyses; the finding was also consistent with the X-ray diffraction patterns of the films and the chemical identity of the sprayed and heat-treated films that were measured using X-ray photoelectron spectroscopy. The sprayed film comprises a characteristic network structure, which contains round particles within the networks, as was observed by field-emission scanning electron microscopy. A scratch test indicated that the shear stress of the sprayed film (21 MPa) significantly improved to 40 and > 133 MPa after heat-treatment at 600 °C and 700 °C, respectively, under Ar gas flow for 10 min. - Highlights: ► CO2 inserted CA films were fabricated on a Ti plate by the aqueous spray method. ► The characteristic network structure of the sprayed film was clarified by FE-SEM. ► Ca10(PO4)6(CO3) · 2CO2 · 3H2O film with a thickness of ca. 1 μm could be deposited. ► A well-adhered film with shear stress of 21 MPa was obtained at low temperatures. ► A stable solution for VOC-free spraying was facilely prepared.

  19. Radiation-damage-controlled He diffusion and 4He/3He spectra in apatite: an example of mutually consistent results from the Grand Canyon (Invited)

    Science.gov (United States)

    Farley, K. A.; Flowers, R. M.

    2009-12-01

    Recent work indicates that He diffusion from apatite is impeded by the accumulation of radiation damage from actinide decay. Supporting evidence includes laboratory diffusion measurements as well as (U-Th)/He dates positively correlated with effective uranium (eU) concentration in certain geologic situations. Here we investigate whether the radiation damage effect can be identified in 4He concentration profiles, as it must be if the system behaves as we anticipate. Apatites from nearby igneous basement samples in the Upper Gorge of the Grand Canyon showing a strong date-eU correlation were proton irradiated, step-heated, and analyzed for 4He/3He spectra. The low eU apatites with younger He dates yielded nearly flat spectra, while the high eU apatites with older He dates yielded highly rounded spectra (see Figure). This implies that the higher eU apatites were partially retaining He while the lower eU apatites were still acting as an open system. Using the RDAAM kinetic model (Flowers et al. 2009) and local geologic constraints we confirm that this behavior is consistent with the observed differences in date and eU, providing compelling evidence that both the He dates and the 4He profiles are sensitive to radiation damage accumulation. Equally importantly, the combination of multiple samples with differing eU and thus differing 4He/3He spectra yields remarkably tight constraints on the time-temperature path experienced by these rocks, from ~90oC down to < 30oC.

  20. The thermal history of the Miocene Ibar Basin (Southern Serbia: new constraints from apatite and zircon fission track and vitrinite reflectance data

    Directory of Open Access Journals (Sweden)

    Andrić Nevena

    2015-02-01

    Full Text Available The Ibar Basin was formed during Miocene large scale extension in the NE Dinaride segment of the Alpine- Carpathian-Dinaride system. The Miocene extension led to exhumation of deep seated core-complexes (e.g. Studenica and Kopaonik core-complex as well as to the formation of extensional basins in the hanging wall (Ibar Basin. Sediments of the Ibar Basin were studied by apatite and zircon fission track and vitrinite reflectance in order to define thermal events during basin evolution. Vitrinite reflectance (VR data (0.63-0.90 %Rr indicate a bituminous stage for the organic matter that experienced maximal temperatures of around 120-130 °C. Zircon fission track (ZFT ages indicate provenance ages. The apatite fission track (AFT single grain ages (45-6.7 Ma and bimodal track lengths distribution indicate partial annealing of the detrital apatites. Both vitrinite reflectance and apatite fission track data of the studied sediments imply post-depositional thermal overprint in the Ibar Basin. Thermal history models of the detritial apatites reveal a heating episode prior to cooling that began at around 10 Ma. The heating episode started around 17 Ma and lasted 10-8 Ma reaching the maximum temperatures between 100-130 °C. We correlate this event with the domal uplift of the Studenica and Kopaonik cores where heat was transferred from the rising warm footwall to the adjacent colder hanging wall. The cooling episode is related to basin inversion and erosion. The apatite fission track data indicate local thermal perturbations, detected in the SE part of the Ibar basin (Piskanja deposit with the time frame ~7.1 Ma, which may correspond to the youngest volcanic phase in the region.

  1. The thermal history of the Miocene Ibar Basin (Southern Serbia): new constraints from apatite and zircon fission track and vitrinite reflectance data

    Science.gov (United States)

    Andrić, Nevena; Fügenschuh, Bernhard; Životić, Dragana; Cvetković, Vladica

    2015-02-01

    The Ibar Basin was formed during Miocene large scale extension in the NE Dinaride segment of the Alpine- Carpathian-Dinaride system. The Miocene extension led to exhumation of deep seated core-complexes (e.g. Studenica and Kopaonik core-complex) as well as to the formation of extensional basins in the hanging wall (Ibar Basin). Sediments of the Ibar Basin were studied by apatite and zircon fission track and vitrinite reflectance in order to define thermal events during basin evolution. Vitrinite reflectance (VR) data (0.63-0.90 %Rr) indicate a bituminous stage for the organic matter that experienced maximal temperatures of around 120-130 °C. Zircon fission track (ZFT) ages indicate provenance ages. The apatite fission track (AFT) single grain ages (45-6.7 Ma) and bimodal track lengths distribution indicate partial annealing of the detrital apatites. Both vitrinite reflectance and apatite fission track data of the studied sediments imply post-depositional thermal overprint in the Ibar Basin. Thermal history models of the detritial apatites reveal a heating episode prior to cooling that began at around 10 Ma. The heating episode started around 17 Ma and lasted 10-8 Ma reaching the maximum temperatures between 100-130 °C. We correlate this event with the domal uplift of the Studenica and Kopaonik cores where heat was transferred from the rising warm footwall to the adjacent colder hanging wall. The cooling episode is related to basin inversion and erosion. The apatite fission track data indicate local thermal perturbations, detected in the SE part of the Ibar basin (Piskanja deposit) with the time frame ~7.1 Ma, which may correspond to the youngest volcanic phase in the region.

  2. Study of retention properties of fluoro-apatite carbonate relative to Ni(II), Am(III) and Th(IV)

    International Nuclear Information System (INIS)

    Apatite minerals and particularly the carbonated species (francolites), are characterized by their chemical and geological stability and also by their capacity to retain durably a large number of elements. Therefore, they should be able to improve the retention properties of the engineered barriers of a deep geological nuclear waste repository. But there is a wide variety of francolites, so we focused our study on a synthetic carbonate fluoro-apatite of formula: Ca10(PO4)5(CO3)(F,OH)3 and on a natural apatite. We first studied their solubility which is an important criterion for the choice of the materials. A particular attention was also paid to the determination of their surface characteristics and to the study of the radionuclide/solution interactions. Sorption experiments have been performed for the three radionuclides and the influence of various parameters has been investigated. The modelling of the sorption isotherms with surface complexation models leads us to estimate the values of the constants associated to the equilibria under consideration. We have also demonstrated that the phosphate ions of the solution participate to the immobilization of americium as the AmPO4,xH2O compound. Both apatites show high retention levels for the actinides: the sorption is quite total over all the pH range studied and the Kd values are close to 104 m3 kg-1. Consequently, the use of apatites could be considered as a specific solution for the immobilisation of heavy elements, specially actinides. Moreover, the results indicate that high amounts of carbonates and impurities do not alter the retention properties of francolites. This bears out the feasibility of the use of natural apatites as additives for the engineered barrier materials. (author)

  3. Nucleation and growth of biomimetic apatite layers on 3D plotted biodegradable polymeric scaffolds : effect of static and dynamic coating conditions

    OpenAIRE

    de Oliveira, A. L.; Costa, S. A.; Sousa, R.A.; Reis, R.L.

    2009-01-01

    Apatite layers were grown on the surface of newly developed starch/polycaprolactone (SPCL)-based scaffolds by a 3D plotting technology. To produce the biomimetic coatings, a sodium silicate gel was used as nucleating agent, followed by immersion in a simulated body fluid (SBF) solution. After growing a stable apatite layer for 7 days, the scaffolds were placed in SBF under static, agitated (80 strokes min!1) and circulating flow perfusion (Q = 4 ml min!1; tR = 15 s) for up to 14 days...

  4. Development of HydroxyCarbonate Apatite on hybrid polymers used in fixed restorations modified by bioactive glass

    Science.gov (United States)

    Georgantzi, B.; Papadopoulou, L.; Zorba, T.; Garefis, P.; Paraskevopoulos, K.; Koidis, P.

    2004-03-01

    The incorporation of a bioactive glass in the structure of hybrid polymers used in dentistry for the construction of fixed prosthetic restorations could induce the expression of bioactivity, leading to the possibility of periodontal tissues reattachment. Hybrid polymer specimens and polymer specimens modified by bioactive glass were prepared and used as control for the surface morphology examination by Scanning Electron Microscopy with associated Dispersive Spectroscopy Analysis (SEM-EDS) and for surface characterization with Fourier Transform Infrared Spectroscopy (FTIR). Furthermore, hybrid polymer specimens modified by bioactive glass were immersed in simulated body fluid (SBF) at 37 °C for different time intervals and were examined by SEM-EDS and FTIR. After 4 days immersion time a dense and continuous apatite layer covered almost the entire modified surface of the specimens. The molar Ca/P ratio reached the value of 1.79. The apatite layer showed a thickness of 1?m and was attached to the substrate, while bioactive glass particles were still present in polymer mass.

  5. Incorporating 3-D parent nuclide zonation for apatite 4He/3He thermochronometry: An example from the Appalachian Mountains

    Science.gov (United States)

    Fox, Matthew; McKeon, Ryan E.; Shuster, David L.

    2014-11-01

    ability to constrain km-scale exhumation with apatite 4He/3He thermochronometry is well established and the technique has been applied to a range of tectonic and geomorphic problems. However, multiple sources of uncertainty in specific crystal characteristics limit the applicability of the method, especially when geologic problems require identifying small perturbations in a cooling path. Here we present new 4He/3He thermochronometric data from the Appalachian Mountains, which indicate significant parent nuclide zonation in an apatite crystal. Using LA-ICPMS measurements of U and Th in the same crystal, we design a 3-D model of the crystal to explore the effects of intracrystal variability in radiation damage accumulation. We describe a numerical approach to solve the 3-D production-diffusion equation. Using our numerical model and a previously determined time temperature path for this part of the Appalachians, we find excellent agreement between predicted and observed 4He/3He spectra. Our results confirm this time-temperature path and highlight that for complex U and Th zonation patterns, 3-D numerical models are required to infer an accurate time-temperature history. In addition, our results provide independent and novel evidence for a radiation damage control on diffusivity. The ability to exploit intracrystal differences in 4He diffusivity [i.e., temperature sensitivity) greatly increases the potential to infer complex thermal histories.

  6. In vitro evaluation for apatite-forming ability of cellulose-based nanocomposite scaffolds for bone tissue engineering.

    Science.gov (United States)

    Saber-Samandari, Samaneh; Saber-Samandari, Saeed; Kiyazar, Shiva; Aghazadeh, Jamshid; Sadeghi, Ali

    2016-05-01

    Research on synthetic bioactive bone graft materials has significantly expanded in the past decade. In this study, the nanocomposite scaffold of semi-interpenetrating networks (semi-IPN) cellulose-graft-polyacrylamide/nano-hydroxyapatite was synthesized through free radical polymerization. The scaffolds were fabricated by the freeze-drying technique. The prepared semi-IPN nanocomposite scaffolds were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis. In addition, the mechanical properties (i.e., elastic modulus and compressive strength) of the scaffolds were investigated. The SEM images showed that the pores of the scaffolds were interconnected, and their sizes ranged from 120μm to 190μm. Under optimum conditions, the prepared scaffolds had a compressive strength of 4.80MPa, an elastic modulus of 0.29GPa and a value of 47.37% porosity. Furthermore, the apatite-forming ability of the scaffolds was determined using simulated body fluid (SBF) for 28 days. The results revealed that the new apatite particles could grow on the surface of the scaffolds after a 14-day immersion in SBF. Finally, this study suggests that the prepared semi-IPN nanocomposites that closely mimic the properties of bone tissue could be a promising scaffold for bone tissue engineering. PMID:26836617

  7. Multiple cooling episodes in the Central Tarim (Northwest China) revealed by apatite fission track analysis and vitrinite reflectance data

    Science.gov (United States)

    Chang, Jian; Qiu, Nansheng; Song, Xinying; Li, Huili

    2015-09-01

    Apatite fission track and vitrinite reflectance are integrated for the first time to study the cooling history in the Central Tarim, northwest China. The paleo-temperature profiles from vitrinite reflectance data of the Z1 and Z11 wells showed a linear relationship with depth, suggesting an approximately 24.8 °C/km paleo-geothermal gradient and 2700-3900 m of erosion during the Early Mesozoic. The measured apatite fission track ages from well Z2 in the Central Tarim range from 39 to 159 Ma and effectively record the Meso-Cenozoic cooling events that occurred in Central Tarim. Moreover, two cooling events at 190-140 Ma in the Early Jurassic-Early Cretaceous and 80-45 Ma in the Late Cretaceous-Paleocene revealed by measured AFT data and thermal modeling results are related to the collisions of the Qiangtang-Lhasa terranes and the Greater India Plate with the southern margin of the Eurasian Plate, respectively. This study provides new insights into the tectonic evolution of the Tarim Basin (and more broadly Central Asia) and for hydrocarbon generation and exploration in the Central Tarim.

  8. Study on uptake of europium by the thin film of apatite and smectite mixture using RBS and micro-PIXE

    International Nuclear Information System (INIS)

    Uptake of Eu, one of the rare earth elements, by a thin film of apatite and smectite mixture has been studied. The thin film of approximately few tens of μm in thickness was contacted with Eu solution between 1.0x10-5 and 1.0x10-3 mol l-1 for 2 days at 25 deg. C and at pH 4.5. After separating the thin film from the solution, depth and spatial distributions of Eu were determined by Rutherford backscattering spectroscopy (RBS) system and micro-proton-induced X-ray emission (μ-PIXE) analyzing system, respectively, in the TIARA facility of Japan Atomic Energy Research Institute. RBS spectrum shows that Eu is distributed from the surface to deeper position. This indicates that Eu is not only sorbed on the surface of the thin film, but also penetrates to deeper from the surface. The spatial distribution of Eu obtained by μ-PIXE does not correspond to Si but to P. This is the direct evidence that most of the sorbed Eu are associated with apatite in the thin film. Therefore, it is concluded that RBS and μ-PIXE analyses are effective to examine the sorption behavior of elements on the mixture

  9. Formation of interconnected macropores in apatitic calcium phosphate bone cement with the use of an effervescent additive.

    Science.gov (United States)

    Hesaraki, S; Moztarzadeh, F; Sharifi, D

    2007-10-01

    Calcium phosphate cements (CPCs) can be considered as good candidate for bone tissue engineering because they can be resorbed and take part in the bone remodeling process. Several efforts have been made into improve the resorption rate of the calcium phosphate cement by introducing macropores to the cement matrix. In this investigation a simple and effective method has been presented based on the addition of various amounts of an effervescent agent to the calcium phosphate cement components. The effervescent agent was a mixture of sodium hydrogen carbonate, NaHCO(3) (that was added to the powder phase), and citric acid monohydrate, C(6)H(8)O(7).H(2)O (that was dissolved in the liquid phase). The obtained macroporous samples were characterized by Fourier transform infrared spectrometer, X-ray diffraction, and scanning electron microscopy techniques at 4 h after setting and 3 days after soaking in a special simulated body fluid solution named Hank's balanced salt solution. Mercury intrusion porosimetry was also employed for characterizing the pore volume and pore size distribution in the cement structure. Results showed that the rate of conversion of staring reactant to the apatite phase and the apatite chemistry were significantly changed by using the additive in the cement components. Also both the pore volume and pore size were changed by varying both the amount of effervescent additive and the powder to liquid ratio. PMID:17380498

  10. Multiple cooling episodes in the Central Tarim (Northwest China) revealed by apatite fission track analysis and vitrinite reflectance data

    Science.gov (United States)

    Chang, Jian; Qiu, Nansheng; Song, Xinying; Li, Huili

    2016-06-01

    Apatite fission track and vitrinite reflectance are integrated for the first time to study the cooling history in the Central Tarim, northwest China. The paleo-temperature profiles from vitrinite reflectance data of the Z1 and Z11 wells showed a linear relationship with depth, suggesting an approximately 24.8 °C/km paleo-geothermal gradient and 2700-3900 m of erosion during the Early Mesozoic. The measured apatite fission track ages from well Z2 in the Central Tarim range from 39 to 159 Ma and effectively record the Meso-Cenozoic cooling events that occurred in Central Tarim. Moreover, two cooling events at 190-140 Ma in the Early Jurassic-Early Cretaceous and 80-45 Ma in the Late Cretaceous-Paleocene revealed by measured AFT data and thermal modeling results are related to the collisions of the Qiangtang-Lhasa terranes and the Greater India Plate with the southern margin of the Eurasian Plate, respectively. This study provides new insights into the tectonic evolution of the Tarim Basin (and more broadly Central Asia) and for hydrocarbon generation and exploration in the Central Tarim.

  11. Incorporation of cesium into phosphates of apatitic and rhabdophane lattices. Application to the conditioning of separated radionuclides

    International Nuclear Information System (INIS)

    Two phosphate-based materials were investigated for cesium immobilization after its partitioning from spent nuclear fuel: apatites and rhabdophanes. The incorporation of cesium into the apatitic lattice creates steric stresses. These stresses induce the formation of secondary phases which are rapidly leached. The effectiveness of the cesium immobilization in this material is not therefore validated. A second phosphate CsCaNd(PO4)2 was consistently found at the end of the leach test and its properties were further characterized. The structure of CsCaNd(PO4)2, which is rhabdophane-like, is made of large channels which enable the incorporation of the largest alkaline cations. The synthesis involves two intermediates: the monazite, NdPO4, and a soluble phosphate, CsCaPO4. The study of a rhabdophane with 10 wt.% of cesium reveals satisfactory intrinsic properties: a thermal stability up to 1100 C and a leach rate of 10-2 g/(m2.d). The next step will be to improve the reaction yield. (author)

  12. In vitro biomimetic deposition of apatite on alkaline and heat treated Ti6Al4V alloy surface

    Indian Academy of Sciences (India)

    K Fatehi; F Moztarzadeh; M Solati-Hashjin; M Tahriri; M Rezvannia; R Ravarian

    2008-04-01

    Titanium alloy (Ti6Al4V) substrates, having the ability of biomimetic calcium phosphate-based materials, especially hydroxyapatite deposition in a simulated body fluid (SBF) means of chemical treatment (alkaline treatment) and subsequent heat treatment, was studied. The effects of alkaline treatment time, concentration and heat treatment temperature on the formation of calcium phosphate (carbonate–hydroxyapatite) on Ti6Al4V surface were examined. For this purpose, the metallic substrates were treated in 0, 5 and 10 M NaOH solutions at a temperature of 60 or 80°C for 1 and 3 days. Subsequently the substrate was heat-treated at 500, 600 and 700°C for 1 h for consolidation of the sodium titanate hydrogel layer. Finally, they were soaked in SBF for 1 and 3 days. The substrate surfaces were characterized by the techniques commonly used for bulk material such as scanning electron microscopy (SEM) and thin film X-ray diffraction (TF–XRD). With regard to the SEM and TF–XRD results, the optimum process consists of 3 days soaking in 5 M NaOH in 80°C and subsequent heat treatment at 600°C for 1h. It is worth mentioning that the results showed that the apatite formed within 3 days on the specimen surfaces, however, there was no sign of apatite formation in the control samples (without alkaline and heat treatment) which was treated for up to 3 days immersion in SBF.

  13. Atomistic modelling study of lanthanide incorporation in the crystal lattice of an apatite; Etude par modelisation atomistique de l'incorporation de lanthanides dans le reseau cristallin d'une apatite phosphocalcique

    Energy Technology Data Exchange (ETDEWEB)

    Louis-Achille, V

    1999-07-01

    Studies of natural and synthetic apatites allow to propose such crystals as matrix for nuclear waste storage. The neodymium substituted britholite, Ca{sub 9}Nd(PO{sub 4}){sub 5}(SiO{sub 4})F{sub 2}. is a model for the trivalent actinide storage Neodymium can be substituted in two types of sites. The aim of this thesis is to compare the chemical nature of this two sites in fluoro-apatite Ca{sub 9}(PO{sub 4}){sub 6}F{sub 2} and then in britholite, using ab initio atomistic modeling. Two approaches are used: one considers the infinite crystals and the second considers clusters. The calculations of the electronic structure for both were performed using Kohn and Sham density functional theory in the local approximation. For solids, pseudopotentials were used, and wave functions are expanded in plane waves. For clusters, a frozen core approximation was used, and the wave functions are expanded in a linear combination of Slater type atomic orbitals. The pseudopotential is semi-relativistic for neodymium, and the Hamiltonian is scalar relativistic for the clusters. The validation of the solid approach is performed using two test cases: YPO{sub 4} and ScPO{sub 4}. Two numerical tools were developed to compute electronic deformation density map, and calculate partial density of stases. A full optimisation of the lattice parameters with a relaxation of the atomic coordinates leads to correct structural and thermodynamic properties for the fluoro-apatite, compared to experience. The electronic deformation density maps do not show any significant differences. between the two calcium sites. but Mulliken analysis on the solid and on the clusters point out the more ionic behavior of the calcium in site 2. A neodymium substituted britholite is then studied. Neodymium location only induces local modifications in; the crystalline structure and few changes in the formation enthalpy. The electronic study points out an increase of the covalent character the bonding involving neodymium

  14. Microchemical and structural regular variability of apatites in 'overbuilt' enamel and dentin of human molar teeth

    Energy Technology Data Exchange (ETDEWEB)

    Kuczumow, A., E-mail: kuczon@kul.lublin.pl [Department of Chemistry, Lublin Catholic University, 20-718 Lublin (Poland); Nowak, J. [Department of Chemistry, Lublin Catholic University, 20-718 Lublin (Poland); ChaLas, R. [Department of Conservative Medicine, Lublin Medical University, 20-081 Lublin (Poland)

    2011-10-15

    The aim of a recent paper was to recognize the chemical and structural changes in apatites, which form both the enamel and the dentin of the human tooth. The aim was achieved by scrutinizing the linear elemental profiles along the cross-sections of human molar teeth. Essentially, the task was accomplished with the application of the Electron Probe Microanalysis method and with some additional studies by Micro-Raman spectrometry. All the trends in linear profiles were strictly determined. In the enamel zone they were either increasing or decreasing curves of exponential character. The direction of the investigations was to start with the tooth surface and move towards the dentin-enamel junction (DEJ). The results of the elemental studies were more visible when the detected material was divided, in an arbitrary way, into the prevailing 'core' enamel ({approx}93.5% of the total mass) and the remaining 'overbuilt' enamel. The material in the 'core' enamel was fully stable, with clearly determined chemical and mechanical features. However, the case was totally different in the 'overbuilt enamel', with dynamic changes in the composition. In the 'overbuilt' layer Ca, P, Cl and F profiles present the decaying distribution curves, whereas Mg, Na, K and CO{sub 3}{sup 2-} present the growing ones. Close to the surface of the tooth the mixture of hydroxy-, chlor- and fluor-apatite is formed, which is much more resistant than the rest of the enamel. On passing towards the DEJ, the apatite is enriched with Na, Mg and CO{sub 3}{sup 2-}. In this location, three of six phosphate groups were substituted with carbonate groups. Simultaneously, Mg is associated with the hydroxyl groups around the hexad axis. In this way, the mechanisms of exchange reactions were established. The crystallographic structures were proposed for new phases located close to DEJ. In the dentin zone, the variability of elemental profiles looks different, with

  15. Apatite formation on bioactive calcium-silicate cements for dentistry affects surface topography and human marrow stromal cells proliferation.

    Science.gov (United States)

    Gandolfi, Maria Giovanna; Ciapetti, Gabriela; Taddei, Paola; Perut, Francesca; Tinti, Anna; Cardoso, Marcio Vivan; Van Meerbeek, Bart; Prati, Carlo

    2010-10-01

    The effect of ageing in phosphate-containing solution of bioactive calcium-silicate cements on the chemistry, morphology and topography of the surface, as well as on in vitro human marrow stromal cells viability and proliferation was investigated. A calcium-silicate cement (wTC) mainly based on dicalcium-silicate and tricalcium-silicate was prepared. Alpha-TCP was added to wTC to obtain wTC-TCP. Bismuth oxide was inserted in wTC to prepare a radiopaque cement (wTC-Bi). A commercial calcium-silicate cement (ProRoot MTA) was tested as control. Cement disks were aged in DPBS for 5 h ('fresh samples'), 14 and 28 days, and analyzed by ESEM/EDX, SEM/EDX, ATR-FTIR, micro-Raman techniques and scanning white-light interferometry. Proliferation, LDH release, ALP activity and collagen production of human marrow stromal cells (MSC) seeded for 1-28 days on the cements were evaluated. Fresh samples exposed a surface mainly composed of calcium-silicate hydrates CSH (from the hydration of belite and alite), calcium hydroxide, calcium carbonate, and ettringite. Apatite nano-spherulites rapidly precipitated on cement surfaces within 5 h. On wTC-TCP the Ca-P deposits appeared thicker than on the other cements. Aged cements showed an irregular porous calcium-phosphate (Ca-P) coating, formed by aggregated apatite spherulites with interspersed calcite crystals. All the experimental cements exerted no acute toxicity in the cell assay system and allowed cell growth. Using biochemical results, the scores were: fresh cements>aged cements for cell proliferation and ALP activity (except for wTC-Bi), whereas fresh cementsapatite nano-spherulites; (2) the alpha-TCP doped cement aged for 28 days displayed the highest bioactivity and cell proliferation; (3) the deleterious effect of bismuth on cell

  16. A novel simple strategy for in situ deposition of apatite layer on AZ31B magnesium alloy for bone tissue regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Mousa, Hamouda M. [Department of Bionanosystem Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Department of Engineering Materials and Mechanical Design, Faculty of Engineering, South Valley University, Qena 83523 (Egypt); Lee, Do Hee [Department of Bionanosystem Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Park, Chan Hee, E-mail: biochan@jbnu.ac.kr [Department of Bionanosystem Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Division of Mechanical Design Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Kim, Cheol Sang, E-mail: chskim@jbnu.ac.kr [Department of Bionanosystem Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Division of Mechanical Design Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of)

    2015-10-01

    Graphical abstract: - Highlights: • Anodizing process was used for the surface modification of AZ31B magnesium alloy. • An appetite-like film was deposited on the surface of AZ31B magnesium alloy. • Ceramic film was investigated by XRD and XPS. • Nano-plates growth are observed though the implemented experimental design. • Significant increase in the substrate hardness and surface roughness was observed. - Abstract: In this study, for the first time, the degradation performance of AZ31B Mg alloy was tuned by an in situ deposition of apatite thin layer within a short time in one step. Using Taguchi method for experimental design, anodization process was designed under control conditions (time and voltage), and simulated body fluid (SBF) was used as the electrolyte to nucleate apatite-like compounds. The coated alloy was characterized through field emission scanning electron microscopy (FE-SEM), EDS, X-ray diffraction and XPS analysis. The results show that the applied voltage has a significant effect on the formation of apatite-like layers. Compared to the uncoated samples, microhardness and surface roughness of the coated samples showed remarkably different values. The potentiodynamic polarization results demonstrate that the polarization resistance of the anodized samples is higher than the substrate polarization resistance, thus improving the alloy corrosion resistant. Based on the experimental results, the proposed nanostructure apatite-like coating can offer a promising way to improve the biocompatibility and degradability properties of the Mg alloy for bone tissue regeneration.

  17. Interim Report: 100-NR-2 Apatite Treatability Test: Low Concentration Calcium Citrate-Phosphate Solution Injection for In Situ Strontium-90 Immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Mark D.; Fritz, Brad G.; Mendoza, Donaldo P.; Rockhold, Mark L.; Thorne, Paul D.; Xie, YuLong; Bjornstad, Bruce N.; Mackley, Rob D.; Newcomer, Darrell R.; Szecsody, James E.; Vermeul, Vincent R.

    2008-07-11

    Following an evaluation of potential Sr-90 treatment technologies and their applicability under 100-NR-2 hydrogeologic conditions, U.S. Department of Energy, Fluor Hanford, Inc., Pacific Northwest National Laboratory, and the Washington Department of Ecology agreed that the long-term strategy for groundwater remediation at 100-N Area will include apatite sequestration as the primary treatment, followed by a secondary treatment if necessary (most likely phytoremediation). Since then, the agencies have worked together to agree on which apatite sequestration technology has the greatest chance of reducing Sr-90 flux to the river at a reasonable cost. In July 2005, aqueous injection, (i.e., the introduction of apatite-forming chemicals into the subsurface) was endorsed as the interim remedy and selected for field testing. Studies are in progress to assess the efficacy of in situ apatite formation by aqueous solution injection to address both the vadose zone and the shallow aquifer along the 300 ft of shoreline where Sr-90 concentrations are highest. This report describes the field testing of the shallow aquifer treatment.

  18. Structure and Thermal Expansion of Calcium-Thorium Apatite, [Ca4]F[Ca2Th4]T[(SiO4)6]O2.

    Science.gov (United States)

    Bulanov, Evgeny N; Wang, Jingxian; Knyazev, Alexander V; White, Tim; Manyakina, Marina E; Baikie, Tom; Lapshin, Alexander N; Dong, ZhiLi

    2015-12-01

    Thorium silicate apatite with the formula [Ca3.84Th0.16]F[Ca2.79Th3.21]T(SiO4)6O2 · x(H) was synthesized by solid-state reaction, and its structure refined in P63/m from powder X-ray diffraction (XRD) data using the Rietveld method (a = 9.50172(9) Å, c = 6.98302(8) Å, V = 545.98(1) Å(3); R-Bragg = 2.102%). It was found that thorium partitions strongly to the tunnel (T) 6h position rather than the framework (F) 4f site. Fourier transform infrared spectroscopy revealed only SiO4 tetrahedron, with SiO5 and SiO6 groups, sometimes observed in siliceous apatites absent, at least to the limit of detection of this technique. Thermal expansion of the thorium apatite determined by high-temperature XRD from 298-1173 K found Δa (0.87%) dilation to exceed Δc (0.73%) with increasing temperature consistent with other silicate apatites. PMID:26562353

  19. Multiphase cooling and exhumation of the Krkonoše Piedmont Basin during Mesozoic - Cenozoic basin inversion based on apatite fission track analysis

    Czech Academy of Sciences Publication Activity Database

    Martínek, K.; Svojtka, Martin; Filip, Jiří

    2008-01-01

    Roč. 34, 4/6 (2008), s. 1353003-1353003. ISSN 0161-6951. [International Geological Congress /33./. 06.08.2008-14.08.2008, Oslo] R&D Projects: GA AV ČR KJB3111305 Institutional research plan: CEZ:AV0Z30130516 Keywords : fission track * apatite * Krkonoše Piedmont basin Subject RIV: DB - Geology ; Mineralogy

  20. Provenance and post-sedimentary low-temperature evolution of the James Ross Basin sediments (Antarctic Peninsula) based on zircon and apatite fission-track analysis

    Czech Academy of Sciences Publication Activity Database

    Svojtka, Martin; Murakami, Masaki; Nývlt, D.; Macáková, J.; Filip, Jiří; Mixa, P.

    2007-01-01

    Roč. 71, 15 S1 (2007), A990-A990. ISSN 0046-564X. [Annual V. M. Goldschmidt Conference /17./. 19.08.2007-24.08.2007, Cologne] R&D Projects: GA MŠk 1K05030 Institutional research plan: CEZ:AV0Z30130516 Keywords : fission -track * zircon * apatite * James Ross, * Antarctica Subject RIV: DB - Geology ; Mineralogy

  1. A novel simple strategy for in situ deposition of apatite layer on AZ31B magnesium alloy for bone tissue regeneration

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Anodizing process was used for the surface modification of AZ31B magnesium alloy. • An appetite-like film was deposited on the surface of AZ31B magnesium alloy. • Ceramic film was investigated by XRD and XPS. • Nano-plates growth are observed though the implemented experimental design. • Significant increase in the substrate hardness and surface roughness was observed. - Abstract: In this study, for the first time, the degradation performance of AZ31B Mg alloy was tuned by an in situ deposition of apatite thin layer within a short time in one step. Using Taguchi method for experimental design, anodization process was designed under control conditions (time and voltage), and simulated body fluid (SBF) was used as the electrolyte to nucleate apatite-like compounds. The coated alloy was characterized through field emission scanning electron microscopy (FE-SEM), EDS, X-ray diffraction and XPS analysis. The results show that the applied voltage has a significant effect on the formation of apatite-like layers. Compared to the uncoated samples, microhardness and surface roughness of the coated samples showed remarkably different values. The potentiodynamic polarization results demonstrate that the polarization resistance of the anodized samples is higher than the substrate polarization resistance, thus improving the alloy corrosion resistant. Based on the experimental results, the proposed nanostructure apatite-like coating can offer a promising way to improve the biocompatibility and degradability properties of the Mg alloy for bone tissue regeneration

  2. Cooling and erosion history of the Krkonoše Piedmont Basin (Bohemian Massif, Czech Republic) interpreted from apatite fission-track analysis

    Czech Academy of Sciences Publication Activity Database

    Svojtka, Martin; Filip, Jiří; Martínek, K.

    2005-01-01

    Roč. 7, - (2005), s. 4925-4926. ISSN 1607-7962. [European Geosciences Union, General Assembly. 24.04.2005-29.04.2005, Wien] R&D Projects: GA AV ČR KJB3111305 Institutional research plan: CEZ:AV0Z30130516 Keywords : Krkonoše * apatite * fission-track Subject RIV: DB - Geology ; Mineralogy

  3. Contribution to the study of sorption mechanisms at solid-liquid interfaces: application to the cases of apatites and oxy-hydroxides

    International Nuclear Information System (INIS)

    Sorption-desorption phenomena play an important role in the transport of toxic and radioactive elements in surface and underground water in contact with solid matter. Selenium, which is one of the long-lived radionuclides present in radioactive waste, is characterized by several oxidation states and by anionic species in aqueous solutions. In order to predict its transport, we need a good knowledge of its sorption processes. We have studied the sorption of Se(IV) and Se(VI) on two types of solids present in natural media or which have been proposed as additives to active barriers: hydroxy-apatites, fluoro-apatite and iron oxi-hydroxides (goethite and hematite). Sorption mechanisms have been studied through an approach including several different and complementary methods: titrimetry, zeta-metry, scanning and transmission electron microscopy, infrared spectroscopy, X-ray diffraction, X-ray photo electron spectroscopy, etc... Results showed that Se(VI) is much less sorbed than Se(VI) on both types of solids. For Se(IV) the sorption mechanisms are different for iron oxides and apatites. On oxides, sorption increases when pH decreases. It can be interpreted by a surface complexation model, essentially through an inner sphere complex (monodentate or bidentate). Modelling of Se sorption curves was performed after the determination of acido-basic properties of oxides. However, the determination of the intrinsic properties of oxides is disturbed by several parameters identified as impurities, evolution of the solid in solution, kinetic and solubility of the solid. For apatites, selenium sorption proceeds by exchange with superficial groups, with a maximum of fixation at approximately pH 8. Thanks to XPS measurements and the elaboration of a mathematical model, we could determine the depth of penetration of both selenium and cadmium on apatites. (author)

  4. Bony defect repair in rabbit using hybrid rapid prototyping polylactic co glycolic acid/β tricalciumphosphate collagen I/apatite scaffold and bone marrow mesenchymal stem cells

    Directory of Open Access Journals (Sweden)

    Long Pang

    2013-01-01

    Full Text Available Background: In bone tissue engineering, extracellular matrix exerts critical influence on cellular interaction with porous biomaterial and the apatite playing an important role in the bonding process of biomaterial to bone tissue. The aim of this study was to observe the therapeutic effects of hybrid rapid prototyping (RP scaffolds comprising polylactic-co-glycolic acid (PLGA, β-tricalciumphosphate (β-TCP, collagen I and apatite (PLGA/β-TCP-collagen I/apatite on segmental bone defects in conjunction with combination with bone marrow mesenchymal stem cells (BMSCs. Materials and Methods: BMSCs were seeded into the hybrid RP scaffolds to repair 15 mm defect in the radius of rabbits. Radiograph, microcomputed tomography and histology were used to evaluate new bone formation. Results: Radiographic analysis done from 12 to 36 weeks postoperative period demonstrated that new bone formed at the radial defect site and continues to increase until the medullary cavity is recanalized and remodelling is complete. The bone defect remained unconnected in the original RP scaffolds (PLGA/β-TCP during the whole study. Histological observations conformed to the radiographic images. In hybrid RP scaffold group, woven bone united the radial defect at 12 weeks and consecutively remodeled into lamellar bone 24 weeks postoperation and finally matured into cortical bone with normal marrow cavity after another 12 weeks. No bone formation but connective tissue has been detected in RP scaffold at the same time. Conclusion: Collagen I/apatite sponge composite coating could improve new bone formation in vivo. The hybrid RP scaffold of PLGA/β-TCP skeleton with collagen I/apatite sponge composite coating is a promising candidate for bone tissue engineering.

  5. Thermal modeling and geomorphology of the south border of the Sao Francisco Craton: thermochronology by fission tracks in apatites

    International Nuclear Information System (INIS)

    Recent developments in Fission Track thermochronology associated to mesozoic-cenozoic erosion and tectonic presented trough thematic maps (isotemperature), permit to model the landscape evolution in the southern border of the Sao Francisco craton, southeastern Brazil. Paleotemperature, obtained by fission track analysis in apatite, is closely related to geomorphologic interpretations. The area suffered a complex imprint of endogenous and exogenous processes resulting diversified and differentiated relieves. The landscape is strongly controlled by exhumation between Jurassic and Lower Cretaceous, uplift with tectonic denudation related to crustal heating at the Upper Cretaceous and reactivation of faults until the Miocene. This scenario is a result of reactivations of different brittle structures that accommodate the deformation in the southern border of the Sao Francisco craton. The landscape reflects denudations of up to 3 km with preserved remains of erosive surfaces in the topographical tops and chronocorrelates deposits in the basins of the region. (author)

  6. Study pf apatite accurrence from Gaviao and Serra de Jacabina gold deposit by scintillometry and gamma spectrometry

    International Nuclear Information System (INIS)

    This work presents the results of radiogeologic reconnaissance in the Cenozoic, Mesozoic and Pre-Cambrian formations, localized between Salvador and Miguel Calmon, and of the radiogeologic detail study from areas of the radioactive anomalies: Gaviao in the Riacho do Lacuipe and Canavieira Mine, in the Jacobina, Bahia States Scintilometry and gamma spectrometry results make possible to conclude by the association, in the Gaviao's apatite mineralization with throrium and the gold of the Serra de Corrego's conglamerate with uranium, make possible in the both case, orient the Search and the mining by scintilometry. The petrographic study and the radiactivity elements dispersion, suggest a sedimentary primary origin to the regional metamorphic rocks. In the Canavieiras mine was evident the stratigraphic control of the gold, associated to uranium and pirite in the conglomerates. (C.D.G.)

  7. Gamma dose response of synthetic A-type carbonated apatite in comparison with the response of tooth enamel

    International Nuclear Information System (INIS)

    Synthetic A-type carbonated apatite samples were irradiated at room temperature with 60Co γ rays. Their ESR spectra consist of the lines of CO2- and CO3- radicals of orthorhombic and axial symmetry. The measurements carried out immediately after sample irradiation showed that CO2- species are produced by decomposition of CO3- radicals. Intensity of the CO2- lines in the synthetic and enamel samples increases during the first 400 and 200 h after irradiation, respectively. The dependence of the EPR signal on the dose varies with carbonate content of the sample. The dose response curve for tooth enamel is steeper for the synthetic material. Nonuniformity in the radical site structure in the synthetic samples may arise in the process of sample preparation; this nonuniformity affects the shape of the dose-response curve

  8. Elemental analysis by neutronic radioactivation for biocoral resorption and apatite formation versus time studies after implantation in vivo

    International Nuclear Information System (INIS)

    Previous works carried out on coral show the advantages presented by this bio material used in bony surgery. Its resorbability is due to its bio compatibility and chemical properties. In our laboratory, we have studied the physico-chemical properties, the ossification kinetics and the calcification mechanism of the bio coral. By nuclear radioactivation, we have determined the amounts of Ca, P, Mg, Sr in natural coral, and their variations versus time after implantation in the metaphysis femur. The analysis of these atomic elements allows the study of coral resorption and apatite formation kinetics in coral, in cortical and in spongy bone with two different animal species. (authors). 10 refs., 4 figs., 2 tabs

  9. Partitioning in REE-saturating minerals - Theory, experiment, and modelling of whitlockite, apatite, and evolution of lunar residual magmas

    Science.gov (United States)

    Jolliff, Bradley L.; Haskin, Larry A.; Colson, Russell O.; Wadhwa, Meenakshi

    1993-01-01

    Compositions, including REEs determined by ion microprobe, of apatite and whitlockite in lunar rock assemblages rich in incompatible trace elements, are presented. Concentrations of REEs in lunar whitlockites are high, ranging from about 1.2 to 2.1 REEs (lanthanides + Y) per 56 oxygens. This slightly exceeds the level of two REE atoms per 56 oxygens at which the dominant substitution theoretically becomes saturated. This saturation effect leads to whitlockite REE(3+) D values at typical lunar whitlockite REE concentrations which are 30-40 percent lower than the D values at low concentrations. The halogen-to-phosphorous ratio in lunar melts is a key factor determining the REE distribution with crystalline assemblages. As long as P and REE concentrations of melts are in KREEP-like proportions, one or both of the phosphates will saturate in melts at similar REE concentrations.

  10. The Orientation of Nanoscale Apatite Platelets in Relation to Osteoblastic-Osteocyte Lacunae on Trabecular Bone Surface.

    Science.gov (United States)

    Shah, Furqan A; Zanghellini, Ezio; Matic, Aleksandar; Thomsen, Peter; Palmquist, Anders

    2016-02-01

    The orientation of nanoscale mineral platelets was quantitatively evaluated in relation to the shape of lacunae associated with partially embedded osteocytes (osteoblastic-osteocytes) on the surface of deproteinised trabecular bone of adult sheep. By scanning electron microscopy and image analysis, the mean orientation of mineral platelets at the osteoblastic-osteocyte lacuna (Ot.Lc) floor was found to be 19° ± 14° in the tibia and 20° ± 14° in the femur. Further, the mineral platelets showed a high degree of directional coherency: 37 ± 7% in the tibia and 38 ± 9% in the femur. The majority of Ot.Lc in the tibia (69.37%) and the femur (74.77%) exhibited a mean orientation of mineral platelets between 0° and 25°, with the largest fraction within a 15°-20° range, 17.12 and 19.8% in the tibia and femur, respectively. Energy dispersive X-ray spectroscopy and Raman spectroscopy were used to characterise the features observed on the anorganic bone surface. The Ca/P (atomic %) ratio was 1.69 ± 0.1 within the Ot.Lc and 1.68 ± 0.1 externally. Raman spectra of NaOCl-treated bone showed peaks associated with carbonated apatite: ν1, ν2 and ν4 PO4(3-), and ν1 CO3(2-), while the collagen amide bands were greatly reduced in intensity compared to untreated bone. The apatite-to-collagen ratio increased considerably after deproteinisation; however, the mineral crystallinity and the carbonate-to-phosphate ratios were unaffected. The ~19°-20° orientation of mineral platelets in at the Ot.Lc floor may be attributable to a gradual rotation of osteoblasts in successive layers relative to the underlying surface, giving rise to the twisted plywood-like pattern of lamellar bone. PMID:26472430

  11. Stable isotope (C, O) and monovalent cation fractionation upon synthesis of carbonate-bearing hydroxyl apatite (CHAP) via calcite transformation

    Science.gov (United States)

    Böttcher, Michael E.; Schmiedinger, Iris; Wacker, Ulrike; Conrad, Anika C.; Grathoff, Georg; Schmidt, Burkhard; Bahlo, Rainer; Gehlken, Peer-L.; Fiebig, Jens

    2016-04-01

    Carbonate-bearing hydroxyl-apatite (CHAP) is of fundamental and applied interest to the (bio)geochemical, paleontological, medical and material science communities, since it forms the basic mineral phase in human and animal teeth and bones. In addition, it is found in non-biogenic phosphate deposits. The stable isotope and foreign element composition of biogenic CHAP is widely used to estimate the formation conditions. This requires careful experimental calibration under well-defined boundary conditions. Within the DFG project EXCALIBOR, synthesis of carbonate-bearing hydroxyapatite was conducted via the transformation of synthetic calcite powder in aqueous solution as a function of time, pH, and temperature using batch-type experiments. The aqueous solution was analyzed for the carbon isotope composition of dissolved inorganic carbonate (gas irmMS), the oxygen isotope composition of water (LCRDS), and the cationic composition. The solid was characterized by powder X-ray diffraction, micro Raman and FTIR spectroscopy, SEM-EDX, elemental analysis (EA, ICP-OES) and gas irmMS. Temperature was found to significantly impact the transformation rate of calcite to CHAP. Upon complete transformation, CHAP was found to contain up to 5% dwt carbonate, depending on the solution composition (e.g., pH), both incorporated on the A and B type position of the crystal lattice. The oxygen isotope fractionation between water and CHAP decreased with increasing temperature with a tentative slope shallower than those reported in the literature for apatite, calcite or aragonite. In addition, the presence of dissolved NH4+, K+ or Na+ in aqueous solution led to partial incorporation into the CHAP lattice. How these distortions of the crystal lattice may impact stable isotope discrimination is subject of future investigations.

  12. Surface chemistry and flotation behavior of monazite, apatite, ilmenite, quartz, rutile, and zircon using octanohydroxamic acid collector

    Science.gov (United States)

    Nduwa Mushidi, Josue

    Global increase in rare earth demand and consumption has led to further understanding their beneficiation and recovery. Monazite is the second most important rare earth mineral that can be further exploited. In this study, the surface chemistry of monazite in terms of zeta potential, adsorption density, and flotation response by microflotation using octanohydroxamic acid is determined. Apatite, ilmenite, quartz, rutile, and zircon are minerals that frequently occur with monazite among other minerals. Hence they were chosen as gangue minerals in this study. The Iso Electric Point (IEP) of monazite, apatite, ilmenite, quartz, rutile, and zircon are 5.3, 8.7, 3.8, 3.4, 6.3, and 5.1 respectively. The thermodynamic parameters of adsorption were also evaluated. Ilmenite, rutile and zircon have high driving forces for adsorption with DeltaGads. = 20.48, 22.10, and 22.4 kJ/mol respectively. The free energy of adsorption is 14.87 kJ/mol for monazite. Adsorption density testing shows that octanohydroxamic acid adsorbs on negatively charged surfaces of monazite and its gangue minerals which indicates chemisorption. This observation was further confirmed by microflotation experiments. Increasing the temperature to 80°C raises the adsorption and flotability of monazite and gangue minerals. This does not allow for effective separation. Sodium silicate appeared to be most effective to depress associated gangue minerals. Finally, the fundamentals learned were applied to the flotation of monazite ore from Mt. Weld. However, these results showed no selectivity due to the presence of goethite as fine particles and due to a low degree of liberation of monazite in the ore sample.

  13. Effect of Alkali-Acid-Heat Chemical Surface Treatment on Electron Beam Melted Porous Titanium and Its Apatite Forming Ability

    Directory of Open Access Journals (Sweden)

    Suzan Bsat

    2015-04-01

    Full Text Available Advanced additive manufacturing techniques such as electron beam melting (EBM, can produce highly porous structures that resemble the mechanical properties and structure of native bone. However, for orthopaedic applications, such as joint prostheses or bone substitution, the surface must also be bio-functionalized to promote bone growth. In the current work, EBM porous Ti6Al4V alloy was exposed to an alkali acid heat (AlAcH treatment to bio-functionalize the surface of the porous structure. Various molar concentrations (3, 5, 10M and immersion times (6, 24 h of the alkali treatment were used to determine optimal parameters. The apatite forming ability of the samples was evaluated using simulated body fluid (SBF immersion testing. The micro-topography and surface chemistry of AlAcH treated samples were evaluated before and after SBF testing using scanning electron microscopy and energy dispersive X-ray spectroscopy. The AlAcH treatment successfully modified the topographical and chemical characteristics of EBM porous titanium surface creating nano-topographical features ranging from 200–300 nm in size with a titania layer ideal for apatite formation. After 1 and 3 week immersion in SBF, there was no Ca or P present on the surface of as manufactured porous titanium while both elements were present on all AlAcH treated samples except those exposed to 3M, 6 h alkali treatment. An increase in molar concentration and/or immersion time of alkali treatment resulted in an increase in the number of nano-topographical features per unit area as well as the amount of titania on the surface.

  14. Phanerozoic polycyclic evolution of the southwestern Angola margin: New insights for apatite fission track and (U-Th)/He methodologies

    Science.gov (United States)

    Venancio da Silva, Bruno; Hackspacher, Peter; Carina Siqueira Ribeiro, Marli; Glasmacher, Ulrich Anton

    2016-04-01

    The low-temperature thermochronology has been an important tool to quantify geological process in passive continental margins. In this context, the Angolan margin shows evidence of a polycyclic post-rift evolution marked by different events of uplift, basin inversion and changes in sedimentation rates to the marginal basins, which have controlled the salt tectonics and the hydrocarbon deposits (1,2,3,4). To understand the post break-up evolution of the southwestern Angola margin, it were collected outcrop samples for apatite fission track (AFT) and (U-Th)/He analysis ranging in elevation from 79 m to 1675 m from the coast toward the interior plateau in a profile between Namibe and Lubango cities. The area lies on the edge of Central and Southern Atlantic segments a few kilometers northward the Walvis ridge and encompasses the Archean and Proterozoic basement rocks of the Congo craton. The AFT ages ranging from 120.6 ± 8.9 Ma to 328.8 ± 28.5 Ma and they show a trend of increasing age toward the Great Escarpment with some exceptions. The partial mean track lengths (MTLs) vary between 11.77 ± 1.82 μm to 12.34 ± 1.13 μm with unimodal track length distributions (TDLs). The partial (U-Th)/He ages ranging from 104.85 ± 3.15 Ma to 146.95 ± 4.41 Ma and show the same trend of increasing ages landward, little younger than the AFT ages, which could be interpreted as a fast exhumation episode in Late Jurassic - Early Cretaceous times. The thermal histories modelling has been constrained with the kinetic parameters Dpar (5) and c-axis angle (6) by the software Hefty (7). Both AFT and (U-Th)/He thermal histories modelling indicate three episodes of denudation/uplift driven cooling: (a) from Late Jurassic to Early Cretaceous, (b) a smallest one in the Late Cretaceous and (c) from Oligocene-Miocene to recent, which are compatible with geophysical data of the offshore Namibe basin that estimate the greater thickness of sediments formed in the first and third episodes

  15. Fluids in the Siilinjärvi carbonatite complex, eastern Finland: Fluid inclusion evidence for the formation conditions of zircon and apatite

    Directory of Open Access Journals (Sweden)

    Poutiainen, M.

    1995-06-01

    Full Text Available In the studied zircon and apatite crystals, data recorded two different compositional types of fluid inclusions: Type 1 H2O-CO2, low salinity inclusions (XCO2 = 0.42 to 0.87; XNaCl = 0.001 to 0.005 with bulk densities of 0.73 to 0.87 g/cm3, and Type 2 H2O moderate salinity (XNaCl = 0.03 to 0.06 inclusions with densities of 0.83 to 1.02 g/cm3. The Type 1 inclusions are not present in apatite. In zircon, the observed fluid inclusion types occur in separate domains: around (Type 1 and outside (Type 2 the apparent core. Fluid inclusions are further subdivided into pseudosecondary and secondary inclusions. Using a combination of SEM-EDS, optical characteristics and crushing-stage, various daughter and captive minerals were identified. The fluid inclusion data suggest that the pseudosecondary Type 1 and Type 2 inclusions in zircon and apatite were trapped during the pre-emplacement evolution of the carbonatite at mid-crustal conditions (P≥4 kbar, T≥625°C. The Type 1 fluid was depleted in CO2, during crystal fractionation and cooling leading to a fluid phase enriched in water and alkalies. Fenitization was obviously induced by these saline aqueous fluids. During emplacement of the carbonatite to the present level, zircon phenocrysts were intensively fractured, some Type 1 inclusions were re-equilibrated, and multiphase Type 2 inclusions were trapped. It is assumed that all these inclusions in zircon and the pseudosecondary Type 2 inclusions in apatite have a magmatic origin. In apatite, calcite inclusions occur side-by-side with the secondary Type 2 inclusions. These calcites co-existed with the aqueous fluid during fracturing and metamorphic re-crystallization of apatites. Probably, this metamorphic fluid also is responsible for the transport and deposition of at least some of the calcite at low temperatures (200-350°C.

  16. Micro-computed tomography (μ-CT) as a potential tool to assess the effect of dynamic coating routes on the formation of biomimetic apatite layers on 3D-plotted biodegradable polymeric scaffolds

    OpenAIRE

    de Oliveira, A. L.; Malafaya, P. B.; Costa, S. A.; Sousa, R.A.; Reis, R.L.

    2007-01-01

    This work studies the influence of dynamic biomimetic coating procedures on the growth of bonelike apatite layers at the surface of starch/polycaprolactone (SPCL) scaffolds produced by a 3D-plotting technology. These systems are newly proposed for bone Tissue Engineering applications. After generating stable apatite layers through a sodium silicate-based biomimetic methodology the scaffolds were immersed in Simulated Body Fluid solutions (SBF) under static, agitation a...

  17. Geochemistry of sapphirine-apatite-calcite-bearing gabbroic dykes from the Finero Phlogopite Peridotite (Ivrea-Verbano Zone): evidence for multistage interaction with the ambient peridotite

    Science.gov (United States)

    Tommaso, Giovanardi; Alberto, Zanetti; Maurizio, Mazzucchelli; Tomoaki, Morishita; Antonio, Langone

    2016-04-01

    The Finero Phlogopite-Peridotite (FPP) is a mantle unit outcropping in the northernmost tip of the Ivrea-Verbano Zone (IVZ, Southern Alps). It shows a virtually complete recrystallization due to pervasive to channelled melt migration. The pervasive metasomatism formed a main lithologic association constituted by phlogopite harzburgites associated to phlogopite pyroxenites (mainly olivine-websterites, websterites and orthopyroxenites). These lithologies are also rich in amphibole and do not show significant chemical gradients among them (Zanetti et al., 1999). The channelled migration stages formed dunite bodies, which sometimes contain stratiform chromitites and, more rarely, pyroxenite layers similar to those associated to phlogopite harzburgite. The FPP also shows a discrete number of other, subordinate rock-types, which are characterised by the presence of apatite usually associated to carbonates (i.e. calcite or dolomite) and exhibit marked modal and chemical gradients with respect to the host phlogopite harzburgite. Examples of these lithologies are apatite-dolomite-bearing wehrlites and harzburgites (e.g. Zanetti et al. 1999; Morishita et al., 2008), apatite-calcite zircon-syenites and hornblendites. Ar-Ar amphibole analysis and U-Pb zircon and apatite data return Triassic ages for these rocks, which have been considered to document the time of melt/fluid injection. Notwithstanding the apparent mineralogical and chemical differences with the main lithologic sequences, apatite-carbonates-bearing rocks have been frequently interpreted as cogenetic to phlogopite harzburgites. To debate the petrogenesis of these rocks, a detailed field, petrological and geochemical investigation has been carried out on a swarm of apatite-calcite-bearing gabbroic veins that randomly cut the main lithologic association. Preliminary investigation evidenced as these veins show complex metasomatic haloes and a symmetric internal layering, characterised by crystallisation of magmatic

  18. Mesozoic-Cenozoic tectonic evolution and its relation to sandstone-type uranium mineralization in northern Tarim area--Evidence from apatite fission track

    International Nuclear Information System (INIS)

    The apatite fission track dating and inversion result of geological thermal history of four rock specimens from Sawafuqi area and Talike area in northern Tarim Basin show that two areas uplifted at different ages. The apatite fission track ages of Sawafuqi range from 3.5 to 3.9 Ma, while the ages of Talike range from 53 to 59 Ma. The thermal history recorded by rock samples reveals that there are at least three prominent cooling phases since Late Cretaceous epoch. Detailed study was made on the division of uplifting stages during Mesozoic and Cenozoic tectonic evolution with the existing data in northern Tarim area. And new ideas on tectonic evolution and sandstone-type uranium mineralization have been put forward by combining with the sandstone-type uranium mineralization ages in this area.(authors)

  19. Etude de la migration thermique des produits de fission molybdène, technétium et iode dans les apatites

    OpenAIRE

    Gaillard, Clotilde

    2000-01-01

    Dans l'optique d'un stockage en site géologique des déchets nucléaires à vie longue, les apatites sont envisagées, d'une part comme matrice de confinement d'actinides ou de produits de fission à vie longue, et d'autre part, comme matériaux incorporés dans les barrières ouvragées. Nos travaux consistent à étudier la migration dans les apatites des produits de fission en fonction de la température. Nous avons choisi d'étudier l'iode 129, de période 16 millions d'années et le technétium 99, de p...

  20. 100-NR-2 Apatite Treatability Test: High-Concentration Calcium-Citrate-Phosphate Solution Injection for In Situ Strontium-90 Immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Vermeul, Vincent R.; Fritz, Brad G.; Fruchter, Jonathan S.; Szecsody, James E.; Williams, Mark D.

    2010-09-01

    Following an evaluation of potential strontium-90 (90Sr) treatment technologies and their applicability under 100-NR-2 hydrogeologic conditions, the U.S. Department of Energy (DOE), Fluor Hanford, Inc. (now CH2M Hill Plateau Remediation Company [CHPRC]), Pacific Northwest National Laboratory, and the Washington State Department of Ecology agreed that the long-term strategy for groundwater remediation at the 100-N Area should include apatite as the primary treatment technology. This agreement was based on results from an evaluation of remedial alternatives that identified the apatite permeable reactive barrier (PRB) technology as the approach showing the greatest promise for reducing 90Sr flux to the Columbia River at a reasonable cost. This letter report documents work completed to date on development of a high-concentration amendment formulation and initial field-scale testing of this amendment solution.

  1. New constraints on the origin of the Sierra Madre de Chiapas (south Mexico) from sediment provenance and apatite thermochronometry

    Science.gov (United States)

    Witt, C.; Brichau, S.; Carter, A.

    2012-12-01

    The timing and source of deformation responsible for formation of the Sierra Madre de Chiapas (south Mexico) are unclear. To address this, apatite fission track and U-Th-He thermochronometry, combined with zircon U-Pb dating, were performed on bedrock and sedimentary samples of the Sierra Madre de Chiapas to discern timing of exhumation and identify sediment source areas. The U-Pb results show that Paleocene-Eocene terrigenous units outcropping at the northern section of the Sierra were mostly derived from Grenville (˜1 Ga) basement whereas the internal sections of the chain yield mainly Permian to Triassic ages (circa 270-230 Ma) typical of the Chiapas massif complex. Grenville-sourced sediments are most probably sourced by the Oaxacan block or the Guichicovi complex and were deposited to the north of the Sierra in a foreland setting related to a Laramide deformation front. Other possibly source areas may be related to metasedimentary units widely documented at the south Maya block such as the Baldi unit. The apatite fission track and U-Th-He data combined with previously published results record three main stages in exhumation history: (1) slow exhumation between 35 and 25 Ma affecting mainly the Chiapas massif complex; (2) fast exhumation between 16 and 9 Ma related to the onset of major strike-slip deformation affecting both the Chiapas massif complex and Chiapas fold-and-thrust belt; and (3) a 6 to 5 Ma period of rapid cooling that affected the Chiapas fold-and-thrust belt, coincident with the landward migration of the Caribbean-North America plate boundaries. These data suggest that most of the topographic growth of the Sierra Madre de Chiapas took place in the middle to late Miocene. The new thermochronological evidence combined with stratigraphic and kinematic information suggests that the left-lateral strike-slip faults bounding the Chiapas fold-and-thrust belt to the west may have accommodated most of the displacement between the North American and

  2. Mesozoic exhumation in the coastal region of NW Iberia: Preliminary constraints from apatite fission-track cooling ages

    Science.gov (United States)

    Alvarez-Marrón, Joaquina; Barbero, Luis; Menéndez-Duarte, Rosana; Fernández, Susana

    2013-04-01

    Apatite fission-track (AFT) ages from the Iberian Massif, along the northern coastal region in Galicia are presented. The study aims at unravelling the exhumation history of this higher topography coastal region, the so-called Rías Altas region, next to the northern Iberian margin. The rough topography region is bound to the south by the WNW-ESE trending As Pontes dextral strike-slip fault zone. This fault was active since ca. 30 Ma (Rupelian) up to ca. 21 Ma (Aquitanian). The area comprises mainly Late Proterozoic to Paleozoic metamorphic and igneous rocks from the hinterland of the Variscan orogen. A N-S AFT ages profile from the coast to the southern block of the As Pontes fault reveal progressively younger ages toward the south with the oldest ages (242 ± 12 Ma) located near the coast and the youngest age being 124 ± 7 Ma. The AFT ages at both sides of the As Pontes fault in samples taken at the same elevation are similar within error (124 ± 7and 127 ± 7 Ma) indicating that this strike-slip fault did not cause significant differential exhumation during Oligocene-Early Miocene times. Another important feature shown by these data is that the age-elevation relationship (AER) is negative, the youngest ages being located at the highest elevation (ca. 1000 m. a. s. l). This agrees with recent published data from the easternmost part of the present study area and is an indication of Post-Early Cretaceous long residence time within the upper 2 or 3 km of the crust at temperatures lower than those of the apatite partial annealing zone (60 to 120°C). We interpret the registered exhumation history as mostly related to rifting processes in Pre-Early Cretaceous times. Possibly recording surface processes associated to the two stage rifting episodes in the Triassic and in the Late Jurassic-Early Cretaceous that culminated with formation of the north Iberian Margin. The negative AER suggests that since Early Cretaceous times the whole area underwent topographic changes

  3. Production and in vitro characterization of 3D porous scaffolds made of magnesium carbonate apatite (MCA)/anionic collagen using a biomimetic approach

    International Nuclear Information System (INIS)

    3D porous scaffolds are relevant biomaterials to bone engineering as they can be used as templates to tissue reconstruction. The aim of the present study was to produce and characterize in vitro 3D magnesium-carbonate apatite/collagen (MCA/col) scaffolds. They were prepared by using biomimetic approach, followed by cross-linking with 0.25% glutaraldehyde solution (GA) and liofilization. Results obtained with Fourier-transform infrared spectroscopy (FT-IR) confirmed the type-B carbonate substitution, while by X-ray diffraction (XRD), a crystallite size of ∼ 10 nm was obtained. Optical and electron microscopy showed that the cylindrical samples exhibited an open-porous morphology, with apatite nanocrystals precipitated on collagen fibrils. The cross-linked 3D scaffolds showed integrity when immersed in culture medium up to 14 days. Also, the immersion of such samples into an acid buffer solution, to mimic the osteoclastic resorption environment, promotes the release of important ions for bone repair, such as calcium, phosphorus and magnesium. Bone cells (SaOs2) adhered, and proliferated on the 3D composite scaffolds, showing that synthesis and the cross-linking processes did not induce cytotoxicity. Highlights: • 3D scaffolds of Mg-carbonate–apatite and anionic-collagen were produced. • The biomimetic approach and the cross-linking with 0.25% GA solution were employed. • The scaffolds showed open-porous structure and apatite crystals on collagen fibrils. • The cross-linked scaffolds exhibited integrity when immersed in culture medium. • SaOs2 cells adhered and proliferated on the cross-linked scaffolds confirming no cytotoxicity

  4. Radiation-induced amorphization of Ce-doped Mg2Y8(SiO4)6O2 silicate apatite

    Science.gov (United States)

    Zhou, Jianren; Yao, Tiankai; Lian, Jie; Shen, Yiqiang; Dong, Zhili; Lu, Fengyuan

    2016-07-01

    Ce-doped Mg2Y8(SiO4)6O2 silicate apatite (Ce = 0.05 and 0.5) were irradiated with 1 MeV Kr2+ ion beam irradiation at different temperatures and their radiation response and the cation composition dependence of the radiation-induced amorphization were studied by in situ TEM. The two Ce-doped Mg2Y8(SiO4)6O2 silicate apatites are sensitive to ion beam induced amorphization with a low critical dose (0.096 dpa) at room temperature, and exhibits significantly different radiation tolerance at elevated temperatures. Ce concentration at the apatite AI site plays a critical role in determining the radiation response of this silicate apatite, in which the Ce3+ rich Mg2Y7.5Ce0.5(SiO4)6O2 displays lower amorphization susceptibility than Mg2Y7.95Ce0.05(SiO4)6O2 with a lower Ce3+ occupancy at the AI sites. The critical temperature (Tc) and activation energy (Ea) change from 667.5 ± 33 K and 0.162 eV of Mg2Y7.5Ce0.5(SiO4)6O2 to 963.6 ± 64 K and 0.206 eV of Mg2Y7.95Ce0.05(SiO4)6O2. We demonstrate that the radiation tolerance can be controlled by varying the chemical composition, and enhanced radiation tolerance is achieved by increasing the Ce concentration at the AI site.

  5. Apatite fission track analysis for revealing tectonic events of the Bayinguole area in the west section of Eastern Kunlun Mountains, northern Qinghai-Tibet Plateau

    International Nuclear Information System (INIS)

    Background: Qimantage is an important tectonic metallogenic belt in western part of East Kunlun Mountain. It has experienced complex geological evolution, and significant mineralization. However, because of the plateau climate and inaccessibility, fewer research works have been done on this area, especially after Indo-sinian epoch. Purpose: Our work is to research tectonic activity, thermal history and uplifting around Bayinguole river in Qimantage belt. Methods: The apatite fission-track method was applied to research the tectonic setting, simulate the thermal history and calculate the uplift size and uplift speed. Results: A series of apatite fission track ages from granitoid samples in Bayinguole area of Eastern Kunlun Mountain were obtained, ranging from 120 Ma to 47 Ma that might be divided into three groups': 120-100 Ma, 67 Ma and 54-47 Ma. These ages reflected tectonic events in this area very well. Conclusions: The 120-100 Ma and 67 Ma ages present collision-convergences of Gangdese terrane and Himalayan terrane with their north-side terranes in Early Cretaceous and Late Cretaceous respectively. The ages of 54-47 Ma reflect post-orogenic stretching events in Eocene. Three stages of thermal evolution history are revealed by apatite fission track modeling in this area. Stage one 180-140 Ma is in the bottom temperature of apatite fission track anneal zone. Stage two 140-13 Ma records slow cooling. The last stage after 13 Ma records rapid cooling with temperature dropped 50℃. The uplifting ranges for these three stages are 1.0 km, 0.6 km and 1.4 km, respectively. The cumulative amount of uplift is about 3.0 km. The formula calculations for the 3 samples have their rock uplifts of 3623 m, 3317 m and 3769 m, respectively, averaging 3570 m, in accordance with the results based on the 3 stage thermal history. (authors)

  6. Effects of Apatite Cement Containing Atelocollagen on Attachment to and Proliferation and Differentiation of MC3T3-E1 Osteoblastic Cells

    OpenAIRE

    Masaaki Takechi; Yoshiaki Ninomiya; Kouji Ohta; Misato Tada; Kazuki Sasaki; Mohammad Zeshaan Rahman; Akira Ohta; Kanji Tsuru; Kunio Ishikawa

    2016-01-01

    To improve the osteoconductivity of apatite cement (AC) for reconstruction of bone defects after oral maxillofacial surgery, we previously fabricated AC containing atelocollagen (AC(ate)). In the present study, we examined the initial attachment, proliferation and differentiation of mouse osteoblastic cells (MC3T3-E1 cells) on the surface of conventional AC (c-AC), AC(ate) and a plastic cell dish. The number of osteoblastic cells showing initial attachment to AC(ate) was greater than those at...

  7. In Vitro Screening of the Apatite-Forming Ability, Biointeractivity and Physical Properties of a Tricalcium Silicate Material for Endodontics and Restorative Dentistry

    OpenAIRE

    Maria Giovanna Gandolfi; Francesco Siboni; Antonella Polimeni; Maurizio Bossù; Francesco Riccitiello; Sandro Rengo; Carlo Prati

    2013-01-01

    Aim: Calcium silicate-based materials are hydraulic self-setting materials with physico-chemical properties suitable for endodontic surgery and good biological/clinical outcomes. The study aim was to evaluate the bio-properties (biointeractivity and apatite-forming ability) and selected physical properties (porosity, water sorption, solubility, and setting time) of Biodentine, a tricalcium silicate material for endodontics and restorative dentistry, compared to that of ProRoot MTA (Mineral ...

  8. Permo-Carboniferous Krkonoše Piedmont Basin inversion: cooling and exhumation during Mesozoic – Cenozoic based on apatite fission track analysis

    Czech Academy of Sciences Publication Activity Database

    Martínek, K.; Svojtka, Martin; Filip, Jiří

    Wroclaw: WIND ;, 2008 - (Wojewoda, J.). s. 14-14 ISBN 978-83-922330-2-2. [Polska Konferencja Sedimentologiczna (POKOS) /3./. 15.09.2008-21.09.2008, Kudowa Zdroj] R&D Projects: GA AV ČR KJB3111305 Institutional research plan: CEZ:AV0Z30130516 Keywords : fission -track * apatite * Krkonoše Piedmont Basin Subject RIV: DB - Geology ; Mineralogy

  9. Apatite Formation and Biocompatibility of a Low Young's Modulus Ti-Nb-Sn Alloy Treated with Anodic Oxidation and Hot Water.

    Directory of Open Access Journals (Sweden)

    Hidetatsu Tanaka

    Full Text Available Ti-6Al-4V alloy is widely prevalent as a material for orthopaedic implants because of its good corrosion resistance and biocompatibility. However, the discrepancy in Young's modulus between metal prosthesis and human cortical bone sometimes induces clinical problems, thigh pain and bone atrophy due to stress shielding. We designed a Ti-Nb-Sn alloy with a low Young's modulus to address problems of stress disproportion. In this study, we assessed effects of anodic oxidation with or without hot water treatment on the bone-bonding characteristics of a Ti-Nb-Sn alloy. We examined surface analyses and apatite formation by SEM micrographs, XPS and XRD analyses. We also evaluated biocompatibility in experimental animal models by measuring failure loads with a pull-out test and by quantitative histomorphometric analyses. By SEM, abundant apatite formation was observed on the surface of Ti-Nb-Sn alloy discs treated with anodic oxidation and hot water after incubation in Hank's solution. A strong peak of apatite formation was detected on the surface using XRD analyses. XPS analysis revealed an increase of the H2O fraction in O 1s XPS. Results of the pull-out test showed that the failure loads of Ti-Nb-Sn alloy rods treated with anodic oxidation and hot water was greater than those of untreated rods. Quantitative histomorphometric analyses indicated that anodic oxidation and hot water treatment induced higher new bone formation around the rods. Our findings indicate that Ti-Nb-Sn alloy treated with anodic oxidation and hot water showed greater capacity for apatite formation, stronger bone bonding and higher biocompatibility for osteosynthesis. Ti-Nb-Sn alloy treated with anodic oxidation and hot water treatment is a promising material for orthopaedic implants enabling higher osteosynthesis and lower stress disproportion.

  10. Scanning force microscopy of 129Iodine surface impact structures in muscovite, zircon and apatite as proxies for damage of simulated fission fragments in solids

    International Nuclear Information System (INIS)

    Using artificially created swift, heavy ions of 129I with a typical fission-fragment mass and specific energies which are common during the spontaneous fission of 238U, the response in minerals commonly used in geochronological dating such as muscovite, zircon and apatite, has been evaluated by the means of Atomic Force Microscopy (AFM). The surface impact structures form hillocks with greater diameters but smaller heights for low-energetic ions and smaller diameters but greater heights for high-energetic ions. The observed hillock widths range from 22 ± 2 nm for low-energetic ions to 17 ± 1 nm for the highest energy in mica. Furthermore, the dimensions formed in apatite for low and high-energy ions range from 53 ± 2 nm to 27 ± 2 nm and from 64 ± 3 nm to 28 ± 1 nm in zircon. With increasing 129I particle energy hillock heights increase, but diameters decrease regardless of mineral orientation. The crystallographic orientation of apatite and zircon also seems to have no effect on hillock dimensions, which are identical for perpendicular and parallel to the c-axis oriented mineral grains. The results support the “Compound Spike” track formation model of Chadderton (2003), which combines the Coulomb ion explosion model with a thermal spike model. - Highlights: ► Swift, high energy 129I ions were implanted in mica, apatite and zircon. ► Atomic Force Microscopy was applied to study ion impact structures on the nanoscale. ► 129I impacts form hillocks which vary in dimension depending on deployed ion energy. ► Mineral orientation has no affect on hillock dimensions. ► Surface ion track formation in zircon supporting the “Compound” spike model

  11. Adsorption of DNA on biomimetic apatites: Toward the understanding of the role of bone and tooth mineral on the preservation of ancient DNA

    OpenAIRE

    Grunenwald, Anne; Keyser, Christine; Sautereau, Anne-Marie; Crubézy, Eric; Ludes, Bertrand; Drouet, Christophe

    2014-01-01

    International audience In order to shed some light on DNA preservation over time in skeletal remains from a physicochemicalviewpoint, adsorption and desorption of DNA on a well characterized synthetic apatite mimicking boneand dentin biominerals were studied. Batch adsorption experiments have been carried out to determinethe effect of contact time (kinetics), DNA concentration (isotherms) and environmentally relevant factorssuch as temperature, ionic strength and pH on the adsorption behav...

  12. Production and in vitro characterization of 3D porous scaffolds made of magnesium carbonate apatite (MCA)/anionic collagen using a biomimetic approach

    Energy Technology Data Exchange (ETDEWEB)

    Sader, Marcia S., E-mail: msader@metalmat.ufrj.br [Prog. Engenharia Metalúrgica e Materiais, COPPE/UFRJ, RJ (Brazil); Martins, Virginia C.A. [Depto. de Química e Física Molecular, IQSC/USP, SP (Brazil); Gomez, Santiago [Dept. Anatomía Patológica, Universidad de Cádiz, Cadiz (Spain); LeGeros, Racquel Z. [Department of Biomaterials and Biomimetics, New York University College of Dentistry, NY (United States); Soares, Gloria A. [Prog. Engenharia Metalúrgica e Materiais, COPPE/UFRJ, RJ (Brazil)

    2013-10-15

    3D porous scaffolds are relevant biomaterials to bone engineering as they can be used as templates to tissue reconstruction. The aim of the present study was to produce and characterize in vitro 3D magnesium-carbonate apatite/collagen (MCA/col) scaffolds. They were prepared by using biomimetic approach, followed by cross-linking with 0.25% glutaraldehyde solution (GA) and liofilization. Results obtained with Fourier-transform infrared spectroscopy (FT-IR) confirmed the type-B carbonate substitution, while by X-ray diffraction (XRD), a crystallite size of ∼ 10 nm was obtained. Optical and electron microscopy showed that the cylindrical samples exhibited an open-porous morphology, with apatite nanocrystals precipitated on collagen fibrils. The cross-linked 3D scaffolds showed integrity when immersed in culture medium up to 14 days. Also, the immersion of such samples into an acid buffer solution, to mimic the osteoclastic resorption environment, promotes the release of important ions for bone repair, such as calcium, phosphorus and magnesium. Bone cells (SaOs2) adhered, and proliferated on the 3D composite scaffolds, showing that synthesis and the cross-linking processes did not induce cytotoxicity. Highlights: • 3D scaffolds of Mg-carbonate–apatite and anionic-collagen were produced. • The biomimetic approach and the cross-linking with 0.25% GA solution were employed. • The scaffolds showed open-porous structure and apatite crystals on collagen fibrils. • The cross-linked scaffolds exhibited integrity when immersed in culture medium. • SaOs2 cells adhered and proliferated on the cross-linked scaffolds confirming no cytotoxicity.

  13. Influence of pentavalent niobium doping on microstructure and electrical conductivity of oxy-apatite La10Si6O27 electrolytes

    International Nuclear Information System (INIS)

    Oxy-apatite type La10Si6–xNbxO27+δ ceramics doped with different pentavalent niobium contents are synthesized via the high-temperature solid state reaction method. Crystal structure and electrical properties of La10Si6–xNbxO27+δ ceramics are investigated by X-ray diffraction, scanning electron microscope, transmission electron microscope, Raman spectroscopy and complex impedance measurements. La10Si6O27 ceramic sintered at 1923 K consists of hexagonal oxy-apatite phase and a small amount of La2SiO5. Pentavalent niobium can partially substitute for tetravalent silicon to form a Nb-doped oxy-apatite structure. However, La2SiO5 phase disappears with increasing the pentavalent niobium content. Some fine La3NbO7 particles are found at grain boundaries of oxy-apatite phase in La10Si6–xNbxO27+δ ceramics when the pentavalent niobium content is beyond 0.1. Raman spectra of La10Si6–xNbxO27+δ ceramics generates three new characteristic modes at 710 cm−1, 342 cm−1 and 136 cm−1 with the addition of different pentavalent niobium contents, which are significantly enhanced especially at x = 0.1 and x = 0.5. These new modes are from Nb−O bonds of La3NbO7 phase and obstruct the interstitial oxide-ion O(5) from conducting in dry atmosphere, thus the grain boundary impedance of La10Si6–xNbxO27+δ ceramics increases correspondingly. La10Si5.9Nb0.1O27.05 ceramic exhibits the highest total conductivity among all the compositions above 873 K

  14. Hanford 100N Area Apatite Emplacement: Laboratory Results of Ca-Citrate-PO4 Solution Injection and Sr-90 Immobilization in 100N Sediments

    Energy Technology Data Exchange (ETDEWEB)

    Szecsody, James E.; Burns, Carolyn A.; Moore, Robert C.; Fruchter, Jonathan S.; Vermeul, Vincent R.; Williams, Mark D.; Girvin, Donald C.; McKinley, James P.; Truex, Michael J.; Phillips, Jerry L.

    2007-10-01

    This report summarizes laboratory scale studies investigating the remediation of Sr-90 by Ca-citrate-PO4 solution injection/infiltration to support field injection activities in the Hanford 100N area. This study is focused on experimentally testing whether this remediation technology can be effective under field scale conditions to mitigate Sr-90 migration 100N area sediments into the Columbia River. Sr-90 is found primarily adsorbed to sediments by ion exchange (99% adsorbed, < 1% in groundwater) in the upper portion of the unconfined aquifer and lower vadose zone. Although primarily adsorbed, Sr-90 is still considered a high mobility risk as it is mobilized by seasonal river stage increases and by plumes of higher ionic strength relative to groundwater. This remediation technology relies upon the Ca-citrate-PO4 solution forming apatite precipitate [Ca6(PO4)10(OH)2], which incorporates some Sr-90 during initial precipitation and additionally slowly incorporates Sr-90 by solid phase substitution for Ca. Sr substitution occurs because Sr-apatite is thermodynamically more stable than Ca-apatite. Once the Sr-90 is in the apatite structure, Sr-90 will decay to Y-90 (29.1 y half-life) then Zr-90 (64.1 h half-life) without the potential for migration into the Columbia River. For this technology to be effective, sufficient apatite needs to be emplaced in sediments to incorporate Sr and Sr-90 for 300 years (~10 half-lives of Sr-90), and the rate of incorporation needs to exceed the natural groundwater flux rate of Sr in the 100N area. A primary objective of this study is to supply an injection sequence to deliver sufficient apatite into subsurface sediments that minimizes initial mobility of Sr-90, which occurs because the injection solution has a higher ionic strength compared to groundwater. This can be accomplished by sequential injections of low, then high concentration injection of Ca-citrate-PO4 solutions. Assessment of low concentration Ca-citrate-PO4, citrate-PO4

  15. Zircon and apatite fission track analyses on mineralization ages and tectonic activities of Tuwu-Yandong porphyry copper deposit in northern Xinjiang, China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The mineralization ages reported in the past in the Tuwu-Yandong copper district not only are different, but also fall into the Hercynian epoch. This study has achieved 9 zircon and 7 apatite fission track analysis results. The zircon fission track ages range from 158 Ma to 289 Ma and the apatite ages are between 64 Ma and 140 Ma. The mineralization accords with the regional tectonics in the copper district. We consider that the zircon fission track age could reveal the mineralization age based on annealing zone temperature of 140-300℃ and retention temperature of ~250℃ for zircon fission track, and metallogenetic temperature of 120-350℃ in this ore district. Total three mineralization epochs have been identified, i.e., 289-276 Ma,232-200 Ma and 165-158 Ma, and indicate occurrence of the mineralization in the Indosinian and Yanshan epochs. Corresponding to apatite fission track ages, the three tectonic-mineralizing epochs are 140-132 Ma, 109-97 Ma and 64 Ma, which means age at about 100℃ after the mineralization. The three epochs lasted 146 Ma, 108 Ma and about 100 Ma from ~250℃ to ~100℃ and trend decrease from early to late. It is shown by the fission track modeling that this district underwent three stages of geological thermal histories, stable in Cretaceous and cooling both before Cretaceous and after 20 Ma.

  16. Roundness of heavy minerals (zircon and apatite) as a provenance tool for unraveling recycling: A case study from the Sefidrud and Sarbaz rivers in N and SE Iran

    Science.gov (United States)

    Zoleikhaei, Yousef; Frei, Dirk; Morton, Andrew; Zamanzadeh, S. Mohammad

    2016-08-01

    In order to improve techniques for provenance studies, and especially to address the question of sediment recycling, morphological changes of two minerals with contrasting durability (zircon and apatite) were tracked during both fluvial transport and littoral reworking. The Sefidrud river system in northern Iran, which drains the Alborz volcano-sedimentary range into the Caspian Sea, and the Sarbaz river system in southeastern Iran, which drains the Makran Accretionary Prism into the Oman Sea, were chosen for this study. To determine source rocks of the grains, and thus their nature in terms of sedimentary cycles, zircon geochronology was conducted on both rivers. The zircon data indicate that most of the Sefidrud sediments are first cycle, derived from crystalline rocks, and the Sarbaz sediments are generally recycled from older wedges of the Makran. Results from SEM analysis show significant differences between the roundness of associated zircon and apatite grains. Zircon grains remain unrounded through several cycles, while apatite grains show abrasion from the early stages of their first cycle.

  17. Evidence for the Multi-Stage Petrogenetic History of the Oka Carbonatite Complex (Québec, Canada as Recorded by Perovskite and Apatite

    Directory of Open Access Journals (Sweden)

    Wei Chen

    2014-05-01

    Full Text Available The Oka complex is amongst the youngest carbonatite occurrences in North America and is associated with the Monteregian Igneous Province (MIP; Québec, Canada. The complex consists of both carbonatite and undersaturated silicate rocks (e.g., ijolite, alnöite, and their relative emplacement history is uncertain. The aim of this study is to decipher the petrogenetic history of Oka via the compositional, isotopic and geochronological investigation of accessory minerals, perovskite and apatite, using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS. The new compositional data for individual perovskite and apatite grains from both carbonatite and associated alkaline silicate rocks are highly variable and indicative of open system behavior. In situ Sr and Nd isotopic compositions for these two minerals are also variable and support the involvement of several mantle sources. U-Pb ages for both perovskite and apatite define a bimodal distribution, and range between 113 and 135 Ma, which overlaps the range of ages reported previously for Oka and the entire MIP. The overall distribution of ages indicates that alnöite was intruded first, followed by okaite and carbonatite, whereas ijolite defines a bimodal emplacement history. The combined chemical, isotopic, and geochronological data is best explained by invoking the periodic generation of small volume, partial melts generated from heterogeneous mantle.

  18. Apatite fission-track data from upper Cretaceous formations in the Yuan'an Graben (China): Constraints on the timing of synsedimentary fault activity

    International Nuclear Information System (INIS)

    Apatite fission-track signatures of upper Cretaceous Formations in the Yuan'an Graben are made to constraint on the timing of the Yuan'an and Tongchenghe synsedimentary fault activity. The apatite fission-track ages range from 102.0 ± 14.6 to 84.1 ± 3.7 Ma with P(χ2) >0.05; the mean confined track lengths of 14.18 ± 0.09 and 14.16 ± 0.08 μm with mean Dpar values of 2.25 ± 0.02 and 2.26 ± 0.03 μm, respectively. These data are interpreted as dating their source-area exhumation, recording the exhumation and cooling of the footwall during major normal faulting. The results indicate that the timing of the Yuan'an and Tongchenghe synsedimentary fault activity occurred at 117–82 Ma and the intensive movement at 100–82 Ma; the onset time of extension in Jianghan Basin is ca. 117 Ma, which is related to the lithospheric extension associated with the subduction of the Pacific Plate beneath the Asian Plate. - Highlights: ► Apatite fission-track dating is used to constraint on the timing of fault activity. ► The onset time of extension in Jianghan Basin is ca. 117 Ma. ► Combination of AFT and ESR to determine a Graben evolution

  19. Contribution to the study of sorption mechanisms at solid-liquid interfaces: application to the cases of apatites and oxy-hydroxides; Contribution a l'etude des mecanismes de sorption aux interfaces solide-liquide: application aux cas des apatites et des oxy-hydroxydes

    Energy Technology Data Exchange (ETDEWEB)

    Duc, M

    2002-11-15

    Sorption-desorption phenomena play an important role in the transport of toxic and radioactive elements in surface and underground water in contact with solid matter. Selenium, which is one of the long-lived radionuclides present in radioactive waste, is characterized by several oxidation states and by anionic species in aqueous solutions. In order to predict its transport, we need a good knowledge of its sorption processes. We have studied the sorption of Se(IV) and Se(VI) on two types of solids present in natural media or which have been proposed as additives to active barriers: hydroxy-apatites, fluoro-apatite and iron oxi-hydroxides (goethite and hematite). Sorption mechanisms have been studied through an approach including several different and complementary methods: titrimetry, zeta-metry, scanning and transmission electron microscopy, infrared spectroscopy, X-ray diffraction, X-ray photo electron spectroscopy, etc... Results showed that Se(VI) is much less sorbed than Se(VI) on both types of solids. For Se(IV) the sorption mechanisms are different for iron oxides and apatites. On oxides, sorption increases when pH decreases. It can be interpreted by a surface complexation model, essentially through an inner sphere complex (monodentate or bidentate). Modelling of Se sorption curves was performed after the determination of acido-basic properties of oxides. However, the determination of the intrinsic properties of oxides is disturbed by several parameters identified as impurities, evolution of the solid in solution, kinetic and solubility of the solid. For apatites, selenium sorption proceeds by exchange with superficial groups, with a maximum of fixation at approximately pH 8. Thanks to XPS measurements and the elaboration of a mathematical model, we could determine the depth of penetration of both selenium and cadmium on apatites. (author)

  20. Development of custom-built bone scaffolds using mesenchymal stem cells and apatite-wollastonite glass-ceramics.

    Science.gov (United States)

    Dyson, Jennifer A; Genever, Paul G; Dalgarno, Kenneth W; Wood, David J

    2007-12-01

    There is a clinical need for new bone replacement materials that combine long implant life with complete integration and appropriate mechanical properties. We have used human mesenchymal stem cells (MSCs) to populate porous apatite-wollastonite (A-W) glass-ceramic scaffolds produced by the layer manufacturing technique, selective laser sintering, to create custom-built bone replacements. Confocal and scanning electron microscopy were used to determine optimal seeding densities and to demonstrate that MSCs adhered and retained viability on the surface of A-W scaffolds over a culture period of 21 days. We found a significant increase in the number of MSCs growing on the scaffolds over 7 days. Using bromodeoxyuridine incorporation we demonstrated that MSCs proliferated on the scaffolds. Using real-time PCR we analyzed the expression of the osteogenic markers alkaline phosphatase, collagen type-I, Cbfa-1, osteocalcin, osteonectin, and osteopontin by MSCs cultured in the absence of osteogenic supplements. The expression of the osteogenic markers by MSCs was equivalent to or significantly greater on A-W scaffolds than on tissue culture plastic. We also identified significantly higher alkaline phosphatase activity on A-W compared to a commercial calcium phosphate scaffold. These results indicate for the first time the biocompatibility and osteo-supportive capacity of A-W scaffolds and their potential as patient-specific bone replacement materials. PMID:17764401

  1. Structure, apatite inducing ability, and corrosion behavior of chitosan/halloysite nanotube coatings prepared by electrophoretic deposition on titanium substrate.

    Science.gov (United States)

    Molaei, A; Amadeh, A; Yari, M; Reza Afshar, M

    2016-02-01

    In this study chitosan/halloysite nanotube composite (CS/HNT) coatings were deposited by electrophoretic deposition (EPD) on titanium substrate. Using HNT particles were investigated as new substituents for carbon nanotubes (CNTs) in chitosan matrix coatings. The ability of chitosan as a stabilizing, charging, and blending agent for HNT particles was exploited. Furthermore, the effects of pH, electrophoretic bath, and sonicating duration were studied on the deposition of suspensions containing HNT particles. Microstructure properties of coatings showed uniform distribution of HNT particles in chitosan matrix to form smooth nanocomposite coatings. The zeta potential results revealed that at pH around 3 there is an isoelectric point for HNT and it would have cathodic and anionic states at pH values less and more than 3, respectively. Therefore, CS/HNT composite deposits were produced in the pH range of 2.5 to 3. The apatite inducing ability of chitosan-HNT composite coating assigned that HNT particles were biocompatible because they formed carbonated hydroxyapatite particles on CS/HNT coating in corrected simulated body fluid (C-SBF). Finally, electrochemical corrosion characterizations determined that corrosion resistance in CS/HNT coating has been improved compared to bare titanium substrate. PMID:26652428

  2. Regenerative potential and anti-bacterial activity of tetracycline loaded apatitic nanocarriers for the treatment of periodontitis

    International Nuclear Information System (INIS)

    Current treatment of periodontal infections includes mechanical debridement, administration of antibiotics and bone grafting. Oral administration of antibiotics results in undesirable side effects, while current modes of local administration are affected by problems concerning allergic response to the polymeric carrier agents. We have developed an osteoconductive drug delivery system composed of apatitic nanocarriers capable of providing sustained delivery of drugs in the periodontium. Calcium deficient hydroxyapatite (CDHA) nanocarriers of different Ca/P ratios were synthesized and characterized using the x-ray diffraction method, transmission electron microscopy, inductively coupled plasma atomic emission spectroscopy, Fourier transform infrared spectroscopy and the BET gas isotherm method. Loading and release studies performed with tetracycline showed a sustained release of up to 88% in phosphate buffered saline over a period of five days. Antibacterial activity studies showed that the tetracycline loaded CDHA (TC-CDHA) nanocarriers were effective against S. aureus and E. coli bacteria. The biocompatibility of the TC-CDHA nanocarriers was demonstrated using an alamar blue assay and further characterized by cell uptake studies. Interestingly, cell uptake of drug loaded CDHA also increased the cellular proliferation of human periodontal ligament fibroblast cells. Hence, it can be concluded that the CDHA nanocarriers are ideal drug delivery agents and have bone regenerative potential for local periodontal applications. (paper)

  3. Thermal evolution of inverted basins: Constraints from apatite fission track thermochronology in the Cuyo Basin, Argentine Precordillera

    International Nuclear Information System (INIS)

    Apatite fission track thermochronology (AFTT) was applied to derive the thermal history of formation and inversion of the oil-bearing Triassic-Cretaceous Cuyo Basin, Argentine Precordillera. The obtained central fission track ages range from 13 to 163Ma, and the mean track lengths from 8.2 to 13.1μm. Based on the integration of AFTT, stratigraphic and structural data, five evolutionary phases are here proposed for the studied area: I-Late Permian cooling related to the extrusion of basement volcanics, and initial extensional regime responsible for the Cuyo Basin formation, II-Triassic-Jurassic heating linked with the filling, and consequent burial, of the Cuyo Basin, III-Jurassic-Paleogene tectonic stabilization, IV-Early Miocene heating related to the load of foreland sedimentation, V-Late Miocene rapid cooling related to the Cuyo Basin inversion. During the Late Miocene, rock units formed in different crustal levels were juxtaposed through thrust, reverse and normal faulting, resulting in contrasting old and very young central fission track ages in closely spaced samples

  4. Late Mesozoic Thermotectonic Evolution of the Jueluotage Range,Eastern Xinjiang, Northwest China: Evidence from Apatite Fission Track Data

    Institute of Scientific and Technical Information of China (English)

    ZHU Wenbin; WAN Jinglin; SHU Liangshu; ZHANG Zhiyong; SU Jinbao; SUN Yan; GUO Jichun; ZHANG Xueyun

    2008-01-01

    Although many authors have emphasized the Cenozoic history of deformation, exhumation and cooling in the Tiaushan area related to the India-Asia collision, very little is known about the Mesozoic history of compression and uplift within the Tianshan. In order to obtain information about the Mesozoic exhumation history and processes of cooling in eastern Tianshan, fission track methods on apatite were used. Sampling was made in the Jueluotage Range. Three samples (Z001-Z003) were taken from granite in borehole ZK6301 of Yandong pluton; the ages range from 97.0 to 87.6 Ma that are much younger than the pluton age which was dated by U-Pb zircon at 334±2 Ma. Two samples in northern piedmont of the Jueluotage Range were collected from Jurassic strata in Dikaner (DK001) and Dananhu (D001) whose ages are 91.5 and 93.4 Ma respectively. The average apparent exhumation rate is 0.039 mm/a calculated by extrapolation on the basis of Yandong samples, indicating an extremely slow exhumation in the Jueluotage Range since the Late Cretaceous. Two Jurassic samples reached the maximum depths after deposition and experienced the maximum temperatures of ca. 105 and 108℃ until the late Early Cretaceous before a period of cooling and exhumation occurred at 114 and 106 Ma.

  5. MECHANISMS CONTROLLING Ca ION RELEASE FROM SOL-GEL DERIVED IN SITU APATITE-SILICA NANOCOMPOSITE POWDER

    Directory of Open Access Journals (Sweden)

    Seyed Mohsen Latifi

    2015-03-01

    Full Text Available Ca ion release from bioactive biomaterials could play an important role in their bioactivity and osteoconductivity properties. In order to improve hydroxyapatite (HA dissolution rate, in situ apatite-silica nanocomposite powders with various silica contents were synthesized via sol-gel method and mechanisms controlling the Ca ion release from them were investigated. Obtained powders were characterized by X-ray diffraction (XRD and transmission electron spectroscopy (TEM techniques, acid dissolution test, and spectroscopy by atomic absorption spectrometer (AAS. Results indicated the possible incorporation of (SiO44- into the HA structure and tendency of amorphous silica to cover the surface of HA particles. However, 20 wt. % silica was the lowest amount that fully covered HA particles. All of the nanocomposite powders showed more Ca ion release compared with pure HA, and HA - 10 wt. % silica had the highest Ca ion release. The crystallinity, the crystallite size, and the content of HA, along with the integrity, thickness, and ion diffusion possibility through the amorphous silica layer on the surface of HA, were factors that varied due to changes in the silica content and were affected the Ca ion release from nanocomposite powders.

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

    Energy Technology Data Exchange (ETDEWEB)

    Anandan, C., E-mail: canandan@nal.res.in; Mohan, L.; Babu, P. Dilli

    2014-03-01

    Highlights: • Titanium alloy β21S was coated with Mo doped DLC. • XRD, XPS and micro Raman show that Mo is present in the form of carbide. • Mo doping facilitates apatite growth on DLC during immersion in Hanks’ solution. • Mo doped DLC sample shows better passivation behavior in Hanks’ solution. - Abstract: 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.

  7. Injectability, microstructure and release properties of sodium fusidate-loaded apatitic cement as a local drug-delivery system.

    Science.gov (United States)

    Noukrati, Hassan; Cazalbou, Sophie; Demnati, Imane; Rey, Christian; Barroug, Allal; Combes, Christèle

    2016-02-01

    The introduction of an antibiotic, sodium fusidate (SF), into the liquid phase of calcium carbonate-calcium phosphate (CaCO3-CaP) bone cement was evaluated, considering the effect of the liquid to powder ratio (L/P) on the composition and microstructure of the set cement and the injectability of the paste. In all cases, we obtained set cements composed mainly of biomimetic carbonated apatite analogous to bone mineral. With this study, we evi-denced a synergistic effect of the L/P ratio and SF presence on the injectability (i.e., the filter-pressing pheno-menon was suppressed) and the setting time of the SF-loaded cement paste compared to reference cement (without SF). In addition, the in vitro study of SF release, according to the European Pharmacopoeia recommendations, showed that, regardless of the L/P ratio, the cement allowed a sustained release of the antibiotic over 1month in sodium chloride isotonic solution at 37°C and pH7.4; this release is discussed considering the microstructure characteristics of SF-loaded cements (i.e., porosity, pore-size distribution) before and after the release test. Finally, modelling antibiotic release kinetics with several models indicated that the SF release was controlled by a diffusion mechanism. PMID:26652362

  8. Thermal History of Rocks in the Shiwandashan Basin, Southern China: Evidence from Apatite Fission-Track Analysis

    Institute of Scientific and Technical Information of China (English)

    Wang Xinwei; Wang Xinwen; Ma Yongsheng

    2005-01-01

    Based on interpretations of the apatite fission-track analysis data for 10 outcrop samples and forward modeling of confined fission-track length distributions, the thermal history of rocks in the Shiwandashan basin and its adjacent area, southern China, has been qualitatively and semi-quantitatively studied. The results reflect several features of the thermal history. Firstly, all the samples have experienced temperatures higher than 60-70 ℃. Secondly, the time that the basement strata (T1b) on the northwestern side of the Shiwandashan basin were uplifted and exhumed to the unannealed upper crust (with a paleogeotemperature of below 60-70 ℃) is much earlier than the basement rocks (γ15) on the southeastern side of the basin. Thirdly, the thermal history of samples from the basin can be divided into six stages, I.e., the fast burial and heating stage (220-145 Ma), the transient cooling stage (145-135 Ma), the burial and heating stage (135-70 Ma), the rapid cooling stage (70-50 Ma), the relatively stable stage (50-20 Ma) and another rapid cooling stage (20 Ma to present).

  9. Degassing pathways of Cl-, F-, H-, and S-bearing magmas near the lunar surface: Implications for the composition and Cl isotopic values of lunar apatite

    Science.gov (United States)

    Ustunisik, G. K.; Nekvasil, H.; Lindsley, D. H.; McCubbin, F. M.

    2015-12-01

    Experimental degassing of H-, F-, Cl-, C-, and S-bearing species from volatile-bearing magma of lunar composition at low P and fO2 close to quartz-iron-fayalite indicates that the composition of the fluid/vapor phase that is lost changes over time. A highly H-rich vapor phase is exsolved within the first 10 min. of degassing leaving behind a melt that is effectively dehydrated. Some Cl, F, and S is also lost during this time, presumably as HCl, HF, and H2S gaseous species; however much of the original inventory of Cl, F, and S components are retained in the melt. After 10 min., the exsolved vapor is dry and dominated by S- and halogen-bearing phases, presumably consisting of metal halides and sulfides, which evolves over time towards F enrichment. This vapor evolution provides important constraints on the geochemistry of volatile-bearing lunar phases that form subsequent to or during degassing. The rapidity of H loss suggests that little if any OH-bearing apatite will crystallize from surface or near surface (≈7m) melts and that degassing of lunar magmas will cause the compositions of apatites to evolve first towards the F-Cl apatite binary and eventually towards end member fluorapatite during crystallization. During the stage of loss of primarily H component from the melt, Cl would have been lost primarily as HCl, which is reported not to fractionate Cl isotopes at magmatic temperatures. After the loss of H-bearing species, continued loss of Cl would result in the degassing of metal chlorides, as a mechanism to fractionate Cl isotopes. After the onset of metal chloride degassing, the δ37Cl of the melt would increase to +6 (82% Cl loss), +8 (85% Cl loss), and +20‰ (95% Cl loss) at 1, 4, and 6 hours, respectively, approximated in a computed trajectory of δ37Cl values in basalt during degassing of FeCl2. This strong enrichment of 37Cl in the melt after metal chloride volatilization is fully consistent with values measured for the non-leachates of a variety of

  10. Apatite fission track dating and long-term landscape evolution of the South Atlantic passive continental margin in the region of the Sierras Septentrionales in eastern Argentina

    Science.gov (United States)

    Pfister, S.; Glasmacher, P. A.; Kollenz, S.

    2013-12-01

    To understand the evolution of the passive continental margin in Argentina apatite fission track dating is an appropriate method, which will lead to new conclusions in this area. The Tandilia System, also called Sierras Septentrionales, is located south of the Río de la Plato Craton in eastern Argentina in the state of Buenos Aires. North of the hills Salado basin is orientated whereas the Claromeó basin is located south of the mountain range. In contrary to most basins along the southamerican passive continental margin the Tandilia-System and the neighbouring basins trend perpendicular to the coast line. The topography ranges between 50 and 250m within the study area and is therefore fairly flat. The igneous-metamorphic basement is pre-proterozoic in age build up of mainly granitic-tonalitic gneisses, migmatites, amphibolites, some ultramafic rocks and granitoid plutons and is overlain by a series of Neoproterozoic to early Paleozoic sediments (Cingolani, 2010). The aim of the study is to evaluate the long-term landscape evolution of the passive continental margin in eastern Argentina in terms of thermal history and exhumation. For that purpose samples were taken from the Sierra Septentrionales basement analyzed for the apatite-FT method. The results so far indicate apatite fission track ages between 146.2 (10.1) Ma and 200.4 (12.7) Ma, which shows all samples have been reseted. Still ongoing length measurements will lead to 2D thermo kinematic Hefty (Ketcham, 2005; Ketcham et al., 2009; Ketcham, 2007) models. This will leads to further more insights on the cooling history and tectonic activities in the research area. References: Cingolani C. A. (2010): The Tandilia System of Argentina as a southern extension of the Río de la Plata craton: an overview. Int. J. Earth Sci. (Geol. Rundsch.) (2011) 100:221-242, doi 10.1007/s00531-010-0611-5. Ketcham, R. A. (2005): Forward and inverse modeling of low-temperature thermochronometry data, in Low

  11. Strontium isotope systematics of scheelite and apatite from the Felbertal tungsten deposit, Austria - results of in-situ LA-MC-ICP-MS analysis

    Science.gov (United States)

    Kozlik, Michael; Gerdes, Axel; Raith, Johann G.

    2016-02-01

    The in-situ Sr isotopic systematics of scheelite and apatite from the Felbertal W deposit and a few regional Variscan orthogneisses ("Zentralgneise") have been determined by LA-MC-ICP-MS. The 87Sr/86Sr ratios of scheelite and apatite from the deposit are highly radiogenic and remarkably scattering. In the early magmatic-hydrothermal scheelite generations (Scheelite 1 and 2) the 87Sr/86Sr ratios range from 0.72078 to 0.76417 and from 0.70724 to 0.76832, respectively. Metamorphic Scheelite 3, formed by recrystallisation and local mobilisation of older scheelite, is characterised by even higher 87Sr/86Sr values between 0.74331 and 0.80689. Statistics allows discriminating the three scheelite generations although there is considerable overlap between Scheelite 1 and 2; they could be mixtures of the same isotopic reservoirs. The heterogeneous and scattering 87Sr/86Sr ratios of the two primary scheelite generations suggest modification of the Sr isotope system due to fluid-rock interaction and isotopic disequilibrium. Incongruent release of 87Sr from micas in the Early Palaeozoic host rocks of the Habach Complex contributed to the solute budget of the hydrothermal fluids and may explain the radiogenic Sr isotope signature of scheelite. Spatially resolved analyses revealed isotopic disequilibrium even on a sub-mm scale within zoned Scheelite 2 crystals indicating scheelite growth in an isotopic dynamical hydrothermal system. Zoned apatite from the W mineralised Early Carboniferous K1-K3 orthogneiss in the western ore field yielded 87Sr/86Sr of 0.72044-0.74514 for the cores and 0.74535-0.77937 for the rims. Values of magmatic apatite cores from the K1-K3 orthogneiss are comparable to those of primary Scheelite 1; they are too radiogenic to be magmatic. The Sr isotopic composition of apatite cores was therefore equally modified during the hydrothermal mineralisation processes, therefore supporting the single-stage genetic model in which W mineralisation is associated with

  12. Hydrogen Isotopic Composition of Apatite in Northwest Africa 7034: A Record of the "Intermediate" H-Isotopic Reservoir in the Martian Crust?

    Science.gov (United States)

    McCubbin, F. M.; Barnes, J. J.; Santos, A. R.; Boyce, J. W.; Anand, M.; Franchi, I. A.; Agee, C. B.

    2016-01-01

    Northwest Africa (NWA) 7034 and its pairings comprise a regolith breccia with a basaltic bulk composition [1] that yields a better match than any other martian meteorite to visible-infrared reflectance spectra of the martian surface measured from orbit [2]. The composition of the fine-grained matrix within NWA 7034 bears a striking resemblance to the major element composition estimated for the martian crust, with several exceptions. The NWA 7034 matrix is depleted in Fe, Ti, and Cr and enriched in Al, Na, and P [3]. The differences in Al and Fe are the most substantial, but the Fe content of NWA 7034 matrix falls within the range reported for the southern highlands crust [6]. It was previously suggested by [4] that NWA 7034 was sourced from the southern highlands based on the ancient 4.4 Ga ages recorded in NWA 7034/7533 zircons [4, 5]. In addition, the NWA 7034 matrix material is enriched in incompatible trace elements by a factor of 1.2-1.5 [7] relative to estimates of the bulk martian crust. The La/Yb ratio of the bulk martian crust is estimated to be approximately 3 [7], and the La/Yb of the NWA 7034 matrix materials ranges from approximately 3.9 to 4.4 [3, 8], indicating a higher degree of LREE enrichment in the NWA 7034 matrix materials. This elevated La/Yb ratio and enrichment in incompatible lithophile trace elements is consistent with NWA 7034 representing a more geochemically enriched crustal terrain than is represented by the bulk martian crust, which would be expected if NWA 7034 represents the bulk crust from the southern highlands. Given the similarities between NWA 7034 and the martian crust, NWA 7034 may represent an important sample for constraining the composition of the martian crust, particularly the ancient highlands. In the present study, we seek to constrain the H isotopic composition of the martian crust using Cl-rich apatite in NWA 7034. Usui et al., [9] recently proposed that a H isotopic reservoir exists within the martian crust that has

  13. Phanerozoic burial and exhumation history of southernmost Norway estimated from apatite fission-track analysis data and geological observations

    Science.gov (United States)

    Japsen, Peter; Green, Paul F.; Bonow, Johan M.; Chalmers, James A.; Rasmussen, Erik S.

    2016-04-01

    We present new apatite fission-track analysis (AFTA) data from 27 basement samples from Norway south of ~60°N. The data define three events of cooling and exhumation that overlap in time with events defined from AFTA in southern Sweden (Japsen et al. 2015). The samples cooled below palaeotemperatures of >100°C in a major episode of Triassic cooling as also reported by previous studies (Rohrman et al. 1995). Our study area is just south of the Hardangervidda where Cambrian sediments and Caledonian nappes are present. We thus infer that these palaeotemperatures reflect heating below a cover that accumulated during the Palaeozoic and Triassic. By Late Triassic, this cover had been removed from the Utsira High, off SW Norway, resulting in deep weathering of a granitic landscape (Fredin et al. 2014). Our samples were therefore at or close to the surface at this time. Palaeotemperatures reached ~80°C prior to a second phase of cooling and exhumation in the Jurassic, following a phase of Late Triassic - Jurassic burial. Upper Jurassic sandstones rest on basement near Bergen, NW of our study area (Fossen et al. 1997), and we infer that the Jurassic event led to complete removal of any remaining Phanerozoic cover in the region adjacent to the evolving rift system prior to Late Jurassic subsidence and burial. The data reveal a third phase of cooling in the early Miocene when samples that are now near sea level cooled below palaeotemperatures of ~60°C. For likely values of the palaeogeothermal gradient, such palaeotemperatures correspond to burial below rock columns that reach well above the present-day landscape where elevations rarely exceed 1 km above sea level. This implies that the present-day landscape was shaped by Neogene erosion. This is in agreement with the suggestion of Lidmar-Bergström et al. (2013) that the near-horizontal Palaeic surfaces of southern Norway are the result of Cenozoic erosion to sea level followed by uplift to their present elevations in a

  14. Alteration, oxygen isotope, and fluid inclusion study of the Meishan iron oxide-apatite deposit, SE China

    Science.gov (United States)

    Yu, Jinjie; Che, Linrui; Wang, Tiezhu

    2015-10-01

    The Meishan deposit (338 Mt at 39 % Fe) comprises massive ores in the main orebody and stockwork and disseminated ores along the main orebody. Four stages of mineralization and related alteration have been identified. The second stage of mineralization, which was the main stage of iron mineralization, formed stringer, disseminated iron ores, as well as the main Meishan orebody. The fourth stage formed small pyrite and/or gold orebodies above or alongside the main magnetite orebody. Stage 2 apatites have homogenization temperatures of 257-485 °C and salinities of 7.3-11 wt% NaCleq. Calculated δ18Ofluid values of magnetite and apatite from the disseminated ores vary between 7.7 and 14.9 ‰, which is similar to values observed in the massive ores (8.1-12.9 ‰). The high-18O fluids at Meishan have been interpreted as being of magmatic-hydrothermal origin. These fluids are indicative of the boiling of ore-forming fluids. Quartz, occurring as cavity fillings, gives homogenization temperatures from 202 to 344 °C, with most values lying between 250 and 330 °C. Corresponding salinities are ˜5 wt% NaCleq. Calculated δ18Ofluid values are +6.4 to +6.8 ‰. These values indicate that the lower-temperature (250-330 °C) quartz was deposited from a cooling magmatic-hydrothermal fluid. Stage 3 siderites contain fluid inclusions that homogenized between 190 and 310 °C, mainly between 210 and 290 °C. Corresponding salinities are 4-8 wt% NaCleq. Stage 4 quartz-carbonate veinlets contain fluid inclusions that homogenized at moderate to low temperatures (150-230 °C) and exhibit low salinities (2-10 wt% NaCl eq). δ18Ofluid values of the mineralizing fluids for the quartz and calcite can be calculated to vary from -0.7 to +5.6 ‰ and +6.3 to +10.2 ‰, respectively. While there is some overlap, the δ18O values of the fluids are generally lower than those observed in the massive and disseminated magnetite ores. δD values for the quartz and calcite vary between -154 and -123

  15. Environment and ecology of East Asian dinosaurs during the Early Cretaceous inferred from stable oxygen and carbon isotopes in apatite

    Science.gov (United States)

    Amiot, Romain; Wang, Xu; Zhou, Zhonghe; Wang, Xiaolin; Lécuyer, Christophe; Buffetaut, Eric; Fluteau, Frédéric; Ding, Zhongli; Kusuhashi, Nao; Mo, Jinyou; Philippe, Marc; Suteethorn, Varavudh; Wang, Yuanqing; Xu, Xing

    2015-02-01

    During the cold Late Barremian-Early Albian interval, terrestrial environments in East Asia were populated by rich and diverse vertebrate faunas characterized by a strong provincialism. The latitudinal gradient of temperature and the existence of geographic barriers likely accounted for some aspects of this heterogeneous distribution of faunas. Other factors, however, such as local environmental conditions and interactions within vertebrate communities, which could have influenced their distribution, have not yet been fully identified and understood. Therefore, new and published oxygen and carbon isotope compositions of apatite from Chinese and Thai reptiles (dinosaurs, crocodilians and turtles) have been analyzed and interpreted in terms of ecology, local air temperature and precipitation amounts. Differences in carbon and oxygen isotope compositions between various groups of sympatric plant-eating dinosaurs (sauropods, ornithopods and ceratopsians) indicate food resources partitioning among them most likely to avoid competition. Mid-latitude environments, where the Jehol Biota flourished, were submitted to cool temperate climatic conditions with Mean Air Temperature (MAT) of 10 ± 4 °C and Mean Annual Precipitations (MAP) of about 600 mm/yr compatible with the existence of forest environments. By contrast, sub-tropical regions, characterized by MAT of about 20-25 °C were either submitted to high amounts of seasonal precipitations (of about 1200 mm/yr in Thailand) or to significant aridity (MAP of about 400 mm/yr in South China). This difference in precipitation regime between Thailand and South China may be attributed to the occurrence of the Coastal Cordillera extending along the East margin of the South China block. These mountain ranges likely prevented humid air masses from the Pacific to penetrate some parts of South China, thus generating a "rain shadow effect". Mosaic environments characterizing East Asia during the Late Early Cretaceous may have acted

  16. Induction of antigen-specific immunity by pH-sensitive carbonate apatite as a potent vaccine carrier

    Energy Technology Data Exchange (ETDEWEB)

    Hebishima, Takehisa [Viral Infectious Diseases Unit, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Tada, Seiichi [Nano Medical Engineering Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Takeshima, Shin-nosuke [Viral Infectious Diseases Unit, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Akaike, Toshihiro [Department of Biomolecular Engineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501 (Japan); Ito, Yoshihiro [Nano Medical Engineering Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Aida, Yoko, E-mail: aida@riken.jp [Viral Infectious Diseases Unit, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

    2011-12-02

    Highlights: Black-Right-Pointing-Pointer To develop effective vaccine, we examined the effects of CO{sub 3}Ap as an antigen carrier. Black-Right-Pointing-Pointer OVA contained in CO{sub 3}Ap was taken up by BMDCs more effectively than free OVA. Black-Right-Pointing-Pointer OVA-immunized splenocytes was activated by OVA contained in CO{sub 3}Ap effectively. Black-Right-Pointing-Pointer OVA contained in CO{sub 3}Ap induced strong OVA-specific immune responses to C57BL/6 mice. Black-Right-Pointing-Pointer CO{sub 3}Ap is promising antigen carrier for the achievement of effective vaccine. -- Abstract: The ability of carbonate apatite (CO{sub 3}Ap) to enhance antigen-specific immunity was examined in vitro and in vivo to investigate its utility as a vaccine carrier. Murine bone marrow-derived dendritic cells took up ovalbumin (OVA) containing CO{sub 3}Ap more effectively than free OVA. Interestingly, mice immunized with OVA-containing CO{sub 3}Ap produced OVA-specific antibodies more effectively than mice immunized with free OVA. Furthermore, immunization of C57BL/6 mice with OVA-containing CO{sub 3}Ap induced the proliferation and antigen-specific production of IFN-{gamma} by splenocytes more strongly than immunization with free OVA. Moreover, no significant differences were detected in the induction of delayed-type hypersensitivity responses, an immune reaction involving an antigen-specific, cell-mediated immune response between OVA-containing CO{sub 3}Ap and OVA-containing alumina salt (Alum), suggesting that CO{sub 3}Ap induced cell-mediated immune response to the same degree as Alum, which is commonly used for clinical applications. This study is the first to demonstrate the induction of antigen-specific immune responses in vivo by CO{sub 3}Ap.

  17. Induction of antigen-specific immunity by pH-sensitive carbonate apatite as a potent vaccine carrier

    International Nuclear Information System (INIS)

    Highlights: ► To develop effective vaccine, we examined the effects of CO3Ap as an antigen carrier. ► OVA contained in CO3Ap was taken up by BMDCs more effectively than free OVA. ► OVA-immunized splenocytes was activated by OVA contained in CO3Ap effectively. ► OVA contained in CO3Ap induced strong OVA-specific immune responses to C57BL/6 mice. ► CO3Ap is promising antigen carrier for the achievement of effective vaccine. -- Abstract: The ability of carbonate apatite (CO3Ap) to enhance antigen-specific immunity was examined in vitro and in vivo to investigate its utility as a vaccine carrier. Murine bone marrow-derived dendritic cells took up ovalbumin (OVA) containing CO3Ap more effectively than free OVA. Interestingly, mice immunized with OVA-containing CO3Ap produced OVA-specific antibodies more effectively than mice immunized with free OVA. Furthermore, immunization of C57BL/6 mice with OVA-containing CO3Ap induced the proliferation and antigen-specific production of IFN-γ by splenocytes more strongly than immunization with free OVA. Moreover, no significant differences were detected in the induction of delayed-type hypersensitivity responses, an immune reaction involving an antigen-specific, cell-mediated immune response between OVA-containing CO3Ap and OVA-containing alumina salt (Alum), suggesting that CO3Ap induced cell-mediated immune response to the same degree as Alum, which is commonly used for clinical applications. This study is the first to demonstrate the induction of antigen-specific immune responses in vivo by CO3Ap.

  18. Uplift and denudation history of the eastern Dead Sea rift flank, SW Jordan: Evidence from apatite fission track thermochronometry

    Science.gov (United States)

    Feinstein, S.; Eyal, M.; Kohn, B. P.; Steckler, M. S.; Ibrahim, K. M.; Moh'd, B. K.; Tian, Y.

    2013-09-01

    Dead Sea rift (DSR), developed along the Dead Sea transform plate boundary, is characterized by salient flanks and morphotectonic asymmetry. Apatite fission track thermochronology (AFT) along ~1200 m high vertical profiles in Neoproterozoic basement and overlying Cambrian sandstone in southwestern Jordan is used to reconstruct timing, magnitude, and rate of uplift and denudation of the eastern DSR flank and examine its relationship to rift development and its flank landscape. Time-temperature models based on AFT data suggest three major Phanerozoic heating and cooling episodes, Late Paleozoic, Early Cretaceous, and Oligocene. The latest episode, on which this study focuses, indicates uplift of ~3.8±0.3 km under a moderate paleogeothermal gradient. About 40% of the uplift was tectonically driven with the remainder attributed to isostatic rebound in response to denudation and erosion. Models suggest that uplift commenced in the Oligocene with a considerable part occurring prior to development of the DSR, despite being ~200 km from the Red Sea-Gulf of Suez rift margin. Uplift is probably part of a regional rearrangement along the western Arabian platform margin occurring at the time of Red Sea rift initiation. Transition from primarily sedimentary layer stripping, most likely by scarp retreat, to one of dominantly incision of the underlying crystalline basement occurred in Late Miocene-Pliocene time following enhanced subsidence and development of a low base level in the DSR. Consequently, the magnitude of uplift by isostatic rebound due to incision exceeded lowering by surface truncation and increased summit elevation and riftward flexing of the flank.

  19. Detrital apatite (U-Th)/He constraints on the exhumational histories of the Arunachal Pradesh Himalaya and the Shillong Plateau

    Science.gov (United States)

    Staisch, L. M.; Clark, M. K.; Niemi, N. A.; Avdeev, B.

    2010-12-01

    Erosion in the Himalaya is driven largely by a strongly coupled system of extreme climatic conditions and active tectonic processes. Spatial and temporal variations in erosion rates along strike are presumably controlled by differences in local climate, seismicity, deformation rates, and lithology. Quantifying the contribution of each of these parameters to the erosional budget of the Himalaya, however, is a nontrivial problem. The easternmost portion of the Himalayan arc offers a natural laboratory to explore the role of climatic influence on erosion rates. Deformation and uplift of the Shillong Plateau since ~8 Ma has created an orographic barrier ~400 km long that shields the eastern Himalaya, in Arunachal Pradesh, India, from a significant proportion of the precipitation carried by the South Asian Monsoon. Long-term exhumation rates derived from the Himalaya west and east of this orographic barrier have been shown to differ by a factor of ~2, a difference ascribed to reduced climatic forcing of erosion in the lee of the Shillong Plateau. Here we present apatite (U-Th)/He thermochronology data from modern detrital samples collected from northeast India. Between 18-20 single grain ages from each catchment were analyzed in order to calculate erosion rates on a 106 yr timescale. Recently developed Bayesian techniques for the inverse modeling of detrital data were used to derive time-temperature histories for each sample. Recent erosion rates modeled for a single south-facing catchment on the Shillong Plateau are modest, ~0.25 km Myr-1, and show a clear increase in exhumation rates at ~8 Ma from rates of indicate that the easternmost Himalaya, as a whole, experienced a significant increase in exhumation rate in the late Miocene, although the absolute rates are lower than observed throughout the Bhutanese and Nepalese Himalaya. The temporal correlation of this increase suggests a regional cause, possibly reflecting changes in the stress field across the India

  20. Mesozoic and Cenozoic uplift and exhumation of the Bogda Mountain, NW China:Evidence from apatite fission track analysis

    Institute of Scientific and Technical Information of China (English)

    Wenhao Tang; Zhicheng Zhang; Jianfeng Li; Ke Li; Zhiwen Luo; Yan Chen

    2015-01-01

    Apatite fission track (AFT) analysis on samples collected from a Paleozoic series is used to constrain the cooling history of the Bogda Mountain, northwest China. AFT ages range from 136.2 to 85.6 Ma and are younger than rock depositional ages and the mean confined track lengths (11.0e13.2 mm) mostly showing unimodal distribution are shorten, indicating significant track-annealing. Thermal histories modeling based on the distribution of fission-track lengths combined with the regional geological data show that two rapid cooling phases occurred in the latest Jurassiceearly Cretaceous and the OligoceneeMiocene. Those new data together with previous published data show that the AFT ages become younger from the southwest to northeast in the western Bogda Mountain and its adjacent areas. The fission-track ages of the southwest area are relatively older (>100 Ma), recording the earlier rapid uplift phase during the late JurassiceCretaceous, while the ages in the north pied-mont of the Bogda Mountain (namely the northeast part) are younger (<60 Ma), mainly reflecting the later rapid uplift phase in the OligoceneeMiocene. The trend of younger AFT ages towards the northeast might be explained by post-Cretaceous large-scale crustal tilting towards the southwest. In the thrust fault-dominated northern limbs of the Bogda Mountain, AFT ages reveal a discontinuous pattern with age-jumps across the major fault zones, showing a possible strata tilting across each thrust faults due to the thrust ramps during the Cenozoic. The two rapid uplift stages might be related to the accretion and collision in the southern margin of the Asian continent during the late Jurassic and late Cenozoic, respectively.

  1. Phanerozoic polycyclic evolution of the southwestern Angola margin: New insights for apatite fission track and (U-Th)/He methodologies

    Science.gov (United States)

    Venancio da Silva, Bruno; Hackspacher, Peter; Carina Siqueira Ribeiro, Marli; Glasmacher, Ulrich Anton

    2016-04-01

    The low-temperature thermochronology has been an important tool to quantify geological process in passive continental margins. In this context, the Angolan margin shows evidence of a polycyclic post-rift evolution marked by different events of uplift, basin inversion and changes in sedimentation rates to the marginal basins, which have controlled the salt tectonics and the hydrocarbon deposits (1,2,3,4). To understand the post break-up evolution of the southwestern Angola margin, it were collected outcrop samples for apatite fission track (AFT) and (U-Th)/He analysis ranging in elevation from 79 m to 1675 m from the coast toward the interior plateau in a profile between Namibe and Lubango cities. The area lies on the edge of Central and Southern Atlantic segments a few kilometers northward the Walvis ridge and encompasses the Archean and Proterozoic basement rocks of the Congo craton. The AFT ages ranging from 120.6 ± 8.9 Ma to 328.8 ± 28.5 Ma and they show a trend of increasing age toward the Great Escarpment with some exceptions. The partial mean track lengths (MTLs) vary between 11.77 ± 1.82 μm to 12.34 ± 1.13 μm with unimodal track length distributions (TDLs). The partial (U-Th)/He ages ranging from 104.85 ± 3.15 Ma to 146.95 ± 4.41 Ma and show the same trend of increasing ages landward, little younger than the AFT ages, which could be interpreted as a fast exhumation episode in Late Jurassic - Early Cretaceous times. The thermal histories modelling has been constrained with the kinetic parameters Dpar (5) and c-axis angle (6) by the software Hefty (7). Both AFT and (U-Th)/He thermal histories modelling indicate three episodes of denudation/uplift driven cooling: (a) from Late Jurassic to Early Cretaceous, (b) a smallest one in the Late Cretaceous and (c) from Oligocene-Miocene to recent, which are compatible with geophysical data of the offshore Namibe basin that estimate the greater thickness of sediments formed in the first and third episodes

  2. Tracing the oxygen triple isotopic composition of tropospheric molecular oxygen in biogenic apatite - a new tool for palaeoclimatology

    Science.gov (United States)

    Pack, A.; Süssenberger, A.; Gehler, A.; Wotzlaw, J.

    2009-04-01

    It has been demonstrated that tropospheric molecular oxygen posses a significant isotope anomaly [1, 2 and refs. therein]. Relative to the rocks- and minerals-defined terrestrial fractionation line (TFL), tropospheric O2 has an anomaly of -0.35‰ [2]. Because almost all oxygen on Earth is contained in rocks, we suggest that the rocks- and minerals-defined TFL [3] should be used as reference when reporting isotope anomalies with ∆17O = δ'17OSMOW - βTFL δ'18OSMOW. We have developed a new technique for the determination of δ17O and δ18O of silicates by means of laser fluorination GC-CF-irmMS. We have determined βTFL to 0.5247 (N > 100), which is identical to the value reported by other laboratories and techniques [2, 3]. The uncertainty in ∆17O is ±0.03 (1σ) for a single analysis. It was suggested that ∆17O of tropospheric O2 can be used as proxy for the global bioactivity rate [GBR, 1] as well as for past atmospheric CO2 concentrations [4]. Past ∆17O of tropospheric O2 can be determined by analyzing O2 trapped in ice [1, 5] or by analyzing sulfates from terrestrial sulphide oxidation [4]. Disadvantage of ice core data is the limitation in time back Elephant). The ∆17O of apatite varies between -0.16‰ for a wood mouse (Apodemus sylvaticus) and +0.04‰ for a wild boar (Sus scrofa). Samples were analyzed between 5 and 7 times in order to reduce the analytical uncertainty to ±0.012-0.025‰. Our data confirm the prediction from mass balance that animals inherit a ∆17O signature from anomalous air O2. We have developed a detailed mass balance for mammals with respect to ∆17O. The mass balance considers the oxygen fluxes (drinking and food water, respired O2, metabolic water, excrements, evaporated water and exhaled CO2). The fractionation in δ18O and ∆17O (from associated β-value) was considered for each of the fluxes. The result is an allometric scaling model for ∆17O as function of log Mb. Predicted and measured data agree within the

  3. Kinetics and mechanism of natural fluoro-apatite dissolution at 25 degrees C and pH from 3 to 12

    International Nuclear Information System (INIS)

    The dissolution rates of natural fluoro-apatite (Flap), Ca10(PO4)6F2, were measured at 25 degrees C in mixed-flow reactors as a function of ph from 3.0 to 11.7, and aqueous calcium, phosphorus, and fluoride concentration. After an initial preferential Ca and/or F release, stoichiometric Ca, P, and F release was observed. Measured Flap dissolution rates decrease with increasing ph at 3 ≤ ph ≤ 7, Flap dissolution rates are ph independent at 7 ≤ ph ≤ 10, and Flap dissolution rates again decrease with increasing ph at ph ≥ 10. Measured Flap dissolution rates are independent of aqueous Ca, P, and F concentration at ph approximate to 3 and ph approximate to 10. Apatite dissolution appears to be initiated by the relatively rapid removal from the near surface of F and the Ca located in the M1 sites, via proton for Ca exchange reactions. Dissolution rates are controlled by the destruction of this F and Ca depleted surface layer. The destruction of this layer is facilitated by the adsorption/penetration of protons into the surface at acidic conditions, and by surface hydration at neutral and basic conditions. Taking into account these two parallel mechanisms, measured fluoro-apatite forward dissolution rates can be accurately described using: r+(mol m-2 s-1)6.61*10-6*(aH+Kads/1+aH+*Kex+(a4Ca2+a1.4F-*a0.6OH-)/(a6H+*Kex) where ai refers to the activity of the i. aqueous species, [CaOH2+] denotes the concentration of hydrated calcium sites at the 2 surface of the leached layer (mol m-2), and Kex and Kads stand for the apparent stability constants of the Ca2+/H+ exchange and adsorption/penetration reactions, respectively. (authors)

  4. LA-ICP-MS U-Pb apatite dating of Lower Cretaceous rocks from teschenite-picrite association in the Silesian Unit (southern Poland

    Directory of Open Access Journals (Sweden)

    Szopa Krzysztof

    2014-08-01

    Full Text Available The main products of volcanic activity in the teschenite-picrite association (TPA are shallow, sub-volcanic intrusions, which predominate over extrusive volcanic rocks. They comprise a wide range of intrusive rocks which fall into two main groups: alkaline (teschenite, picrite, syenite, lamprophyre and subalkaline (dolerite. Previous 40Ar/39Ar and 40K/40Ar dating of these rocks in the Polish Outer Western Carpathians, performed on kaersutite, sub-silicic diopside, phlogopite/biotite as well as on whole rock samples has yielded Early Cretaceous ages. Fluorapatite crystals were dated by the U-Pb LA-ICP-MS method to obtain the age of selected magmatic rocks (teschenite, lamprophyre from the Cieszyn igneous province. Apatite-bearing samples from Boguszowice, Puńców and Lipowa yield U-Pb ages of 103± 20 Ma, 119.6 ± 3.2 Ma and 126.5 ± 8.8 Ma, respectively. The weighted average age for all three samples is 117.8 ± 7.3 Ma (MSWD = 2.7. The considerably smaller dispersion in the apatite ages compared to the published amphibole and biotite ages is probably caused by the U-Pb system in apatite being less susceptible to the effects of hydrothermal alternation than the 40Ar/39Ar or 40K/40Ar system in amphibole and/or biotite. Available data suggest that volcanic activity in the Silesian Basin took place from 128 to 103 Ma with the the main magmatic phase constrained to 128-120 Ma.

  5. STUDY OF AN ASSESSMENT OF THE FATE OF CALCIUM HYDROXY APATITE BLOCK WITH CORTICO CANCELLOUS BONE GRAFT USED IN COMMUNITED FRACTURES OF LONG BONE OF LOWER LIMB

    Directory of Open Access Journals (Sweden)

    Ahmad

    2015-03-01

    Full Text Available INTRODUCTION: In recent years there has been an increasing interest in biologically active calcium phosphate ceramic materials for orthopaedic application. A number of materials from human, animal or non - biological sources have been used to fill defects with or without additional autogenus bone. It would be ideal to have bone substitute w hich is easily fabricated and preserved, is biocompatible with bone, and is biodegradable. The calcium phosphate system, and in particular hydroxyappatite (HA, has long been the subject of intensive investigation. MATERIAL AND METHODS: This observational two year study was undertaken at S.N. Medical College and Hospital, Agra (U.P.. The patients having the comminuted fracture of the long bone of lower limbs were treated with autogenus bone graft and calcium hydroxy Apatite bone block. Functional results w ere presented according to Klemm and Borner (1986 criteria. RESULTS: The total cases studied were 25 out of which 21 cases had fracture of both bones of leg and 4 were of fracture femur. The patients were aged between 15 to 70 years. Most of the patients were males and the common mode of injury was road traffic accident. An excellent result were seen in the majority 9(36% of patients while 8(32% patients showed a good result and 6(24% showed a fair result. 17(68% patients had compound fracture while 8( 32% patients were having closed fracture. CONCLUSION: Calcium Hydroxy Apatite is a suitable alternative to bone graft. There was no evidence of any foreign body reaction and infection at the Calcium Hydroxy Apatite implanted site. There was satisfactory h ealing of all the comminuted fractures. The movement of adjacent joints was nearly normal. No refracture was observed on follow up.

  6. The thermal history of the Miocene Ibar Basin (Southern Serbia): new constraints from apatite and zircon fission track and vitrinite reflectance data

    OpenAIRE

    Andrić Nevena; Fügenschuh Bernhard; Životić Dragana; Cvetković Vladica

    2015-01-01

    The Ibar Basin was formed during Miocene large scale extension in the NE Dinaride segment of the Alpine- Carpathian-Dinaride system. The Miocene extension led to exhumation of deep seated core-complexes (e.g. Studenica and Kopaonik core-complex) as well as to the formation of extensional basins in the hanging wall (Ibar Basin). Sediments of the Ibar Basin were studied by apatite and zircon fission track and vitrinite reflectance in order to define thermal events during basin evolution. Vitrin...

  7. Conventional and microwave-assisted multicomponent reaction of alkyne, halide and sodium azide catalyzed by copper apatite as heterogeneous base and catalyst in water

    Directory of Open Access Journals (Sweden)

    Sandip Kale

    2012-04-01

    Full Text Available The conventional and microwave assisted multicomponent synthesis of disubstituted 1,2,3-triazoles from terminal alkynes and in situ generated organic azide using copper apatite catalyst in water is reported. The catalytic activity is intimately connected to the basicity of the catalyst. The best activities were observed with the copper hydroxyapatite. The catalyst could be used ten times without further treatment and activation under controlled microwave heating. The protocol was also applicable for various alkynes and halides which affords desired product in good to excellent yield.

  8. Post pan-african denudation history of southwestern Madagascar during the complex rift-drift evolution of the island: new aspects from titanite and apatite fission track analyses

    Science.gov (United States)

    Emmel, B.; Jacobs, J.

    2003-04-01

    Titanite and apatite fission track (FT) thermochronology from 53 basement outcrops in southwest Madagascar reveal a protracted post Pan-African history of extensional tectonism, denudation and sedimentation. The titanite FT ages range between 276 ± 14 Ma and 379 ± 38 Ma. Apatite FT ages vary between 117 ± 26 Ma and 379 ± 19 Ma with mean track length scattering between 11.7 ± 0.59 μm and 13.74 ± 0.21 μm. Combined titanite and apatite FT data were used to calculate denudation rates. Samples from the paleo western margin of Madagascar along the N-S striking Pan-African Ejeda shear zone give above-average denudation rates (100-205 mMa-1) during Carboniferous times. The shear zone was probably reactivated during this times. In contrast the calculated denudation rates for samples from the interior of the island are moderate (25-120 mMa-1). Vitrinite reflectance data from the Sakoa coal area as well as titanite and apatite FT data imply that during the Permo-Triassic rifting, the areas along the paleo western margin that previously underwent fast denudation were buried by a sedimentary cover of up to ˜4.5 km. At this time, a graben developed further inland along the NW-SE striking transcontinental Bongolava-Ranotsara shear zone (BRSZ). Modelled time-temperature paths indicate that the area within the BRSZ remained cool and unaffected since Carboniferous times whereas the samples northeast and southwest of the BRSZ suggest phases of differential cooling during Permian-Triassic times. Seismic data from the Morondava basin indicate that during the Middle Jurassic drift between Madagascar and East-Africa a rift jump towards the west occurred. Modelled time-temperature histories of basement units from the paleo western margin, buried during Permo Triassic times, were exhumed during Jurassic times. This is most probably related with the modified rift kinematics and the associated southwest migration of the margin. Modelled time-temperature paths of all samples from

  9. Study of the dissolution of three synthetic minerals: zirconolite, Y-britholite and mono-silicate fluor-apatite; Etude de la solubilite de trois mineraux synthetiques: la zirconolite, la britholite-Y et la fluorapatite monosilicatee

    Energy Technology Data Exchange (ETDEWEB)

    Kamel, N.E.H.; Telmoune, S.A. [Centre de Recherche Nucleaire d' Alger, Div. des Techniques Nucleaires, Alger (Algeria); Ait-Amar, H. [Unitersite des Sciences et de la Technologie Houari Boumediene, Dept. de Genie des Procedes, Alger (Algeria)

    2007-11-15

    In this study, we were interested in the synthesis by natural sintering of three minerals analogue of natural rocks: zirconolite, Y-britholite and mono-silicated fluor-apatite. Cerium was used as an actinide surrogate. A simple physical characterization of the materials was made by X-ray diffraction and by measuring both densities and hardnesses. A static leaching test allowed determining the cerium immobilization capacity of the minerals. The most stable mineral was mono-silicated fluor-apatite, with a maximum amount of released cerium less than 2 %. For zirconolite and Y-britholite, this amount reached 15 and 18 % of the total cerium in the minerals, respectively. For the latter compounds, the cerium content in the materials was too weak, and the chosen synthesis method gave less satisfactory physicochemical mineral properties compared to those obtained for mono-silicated fluor-apatite. (authors)

  10. Fabrication of nanotube arrays on commercially pure titanium and their apatite-forming ability in a simulated body fluid

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Hsueh-Chuan; Wu, Shih-Ching; Hsu, Shih-Kuang [Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, Taiwan, ROC (China); Institute of Biomedical Engineering and Materials Science, Central Taiwan University of Science and Technology, Taiwan, ROC (China); Chang, Yu-Chen [Department of Mechanical and Automation Engineering, Da-Yeh University, Taiwan, ROC (China); Ho, Wen-Fu, E-mail: fujii@nuk.edu.tw [Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung, Taiwan, ROC (China)

    2015-02-15

    In this study, we investigated self-organized TiO{sub 2} nanotubes that were grown using anodization of commercially pure titanium at 5 V or 10 V in NH{sub 4}F/NaCl electrolyte. The nanotube arrays were annealed at 450 °C for 3 h to convert the amorphous nanotubes to anatase and then they were immersed in simulated body fluid at 37 °C for 0.5, 1, and 14 days. The purpose of this experiment was to evaluate the apatite-formation abilities of anodized Ti nanotubes with different tube diameters and lengths. The nanotubes that formed on the surfaces of Ti were examined using a field emission scanning electron microscope, X-ray diffraction, and X-ray photoelectron spectroscope. When the anodizing potential was increased from 5 V to 10 V, the pore diameter of the nanotube increased from approximately 24–30 nm to 35–53 nm, and the tube length increased from approximately 590 nm to 730 nm. In vitro testing of the heat-treated nanotube arrays indicated that Ca-P formation occurred after only 1 day of immersion in simulated body fluid. This result was particularly apparent in the samples that were anodized at 10 V. It was also found that the thickness of the Ca-P layer increases as the applied potential for anodized c.p. Ti increases. The average thickness of the Ca-P layer on Ti that was anodized at 5 V and 10 V was approximately 170 nm and 190 nm, respectively, after immersion in simulated body fluid for 14 days. - Highlights: • TiO{sub 2} nanotube on Ti surface was formed by anodic oxidation in a NaCl/NH{sub 4}F solution. • TiO{sub 2} layers show a tube length of 590 nm and 730 nm at 5 V and 10 V, respectively. • After soaking in SBF, Ca-P layer completely covered the entire nanotubular surfaces. • The Ca-P layer was thicker on the Ti surface anodized at 10 V.

  11. Late stage thermal history of the Songliao Basin and its tectonic implications: Evidence from apatite fission track (AFT) analyses

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Apatite Fission Track (AFT) data from the Songliao Basin indicates that the late stage tectonic movements in the Songliao Basin have zoning in space and episodes in time. The late stage tectonic movements started from the east part of the basin and migrated westward. AFT ages in the east part of the basin are older than those in the west part of the basin, suggesting that the uplift occurred earlier in the east than in the west. The denudation thickness in the east part of the basin is significantly greater than that in the centre and west. The thermal history evolved two episodes of rapid cooling and subsequent slow cooling processes. Age-depth relationship derived from the AFT data indicates a four-episode denudation history. Further Monte Carlo random simulation of the AFT data reveals the four changing points of the thermal evolution at 65 Ma, 43.5 Ma, 28 Ma and 15 Ma, respectively. The uplifting and denudation rates from different episodes of evolution are proportional to the plate convergence rate. Based on the above analyses and the regional geologic background, it is concluded that the late stage thermal events in the Songliao Basin are the far field response to the subduction of the Pacific Plate under the Eurasian Plate. The first episode of the rapid cooling probably started at the end of the Nenjiang Formation, climaxed at the end of the Cretaceous and ceased at the Late Eocene. The subsequent slow cooling lasts another 15 Ma. The first episode of the evolution is the far field response to the major episode of the Yanshan Movement and subsequent series of the tectonic reorganization, especially the directional change of the Pacific Movement and also the subduction of the Indian Plate underneath the Eurasian Plate. While the second episode of the evolution is the far field response to the extension and closure of the Sea of Japan. Extension led to the migration and converging of the mantle heat flow to the Sea of Japan and resulted in the rapid cooling

  12. Spatial variation in exhumation rates across Ladakh and the Karakoram: New apatite fission track data from the Eastern Karakoram, NW India

    Science.gov (United States)

    Wallis, David; Carter, Andrew; Phillips, Richard J.; Parsons, Andrew J.; Searle, Michael P.

    2016-03-01

    Characterization of low-temperature cooling histories and associated exhumation rates is critical for deciphering the recent evolution of orogenic regions. However, these may vary significantly over relatively short distances within orogens. It is pertinent therefore to constrain cooling histories and hence exhumation rates across major tectonic boundaries. We report the first apatite fission track ages from the Karakoram Fault Zone in the Eastern Karakoram range, which forms part of the western margin of the Tibetan Plateau. Ten samples, from elevations of 3477-4875 m, have apatite fission track dates from 3.3 ± 0.3 Ma to 7.4 ± 1.1 Ma. The ages correspond to modeled average erosional exhumation rates of 0.67 + 0.27/-0.18 mm/yr across the Eastern Karakoram. The results are consistent with a trend northward from the Indus suture zone, across the Ladakh terrane and into the Karakoram, in which tectonic uplift associated with crustal thickening increases toward the north, raising elevation and promoting glaciation and generation of extreme relief. As a result, erosion and exhumation rates increase south to north. Present-day precipitation on the other hand varies little within the study area and on a larger scale decreases southwest to northeast across this portion of the orogen. The Eastern Karakoram results highlight the diverse patterns of exhumation driven by regional variations in tectonic response to collision along the western margin of Tibet.

  13. Mesozoic and Cenozoic Cooling History of the Qiangtang Block, Northern Tibet, China: New Constraints from Apatite and Zircon Fission Track Data

    Directory of Open Access Journals (Sweden)

    Chunyan Song

    2013-01-01

    Full Text Available This study used a new set of zircon and apatite fission track ages to quantitatively document the tectonic evolution and cooling histories of the Qiangtang block of the central Tibetan Plateau. The results indicate that the Qiangtang block underwent three cooling stages at ~148 - 73, ~50 - 20, and ~20 - 0 Ma. The three-stage cooling history and tectonic exhumation were controlled by the closure of the Bangong-Nujiang Suture during the Late Jurassic-Late Cretaceous, the India-Asia collision in the Paleogene, and the underthrusting of the India Plate during the Late Cenozoic. In addition to revealing the Late Jurassic-Late Cretaceous cooling events, the annealing patterns of the zircon fission track samples indicate different burial depths, which may help identify the Jurassic basin characteristics of the Qiangtang block. The apatite fission track (AFT ages range from 60 _ 5 Ma to 26 _ 3 Ma, with a mean age of 44 Ma. These ages indicate that the Cenozoic exhumation of the Qiangtang block may have started in the Eocene. Inverse modeling of the AFT data shows that the Qiangtang block had a relatively slow cooling rate of approximately 0.5 - _ Myr-1 from 50 to 20 Ma. After ~20 Ma, most of the samples show evidence for a rapid cooling stage with a cooling rate of 4 - _ Myr-1.

  14. Simultaneous fixation of Cs+, Sr2+ and Re3+ ions into apatite framework: phase stabilization and chemical durability studies for nuclear waste disposal application

    International Nuclear Information System (INIS)

    Cs, Sr2+ and rare earth ions substituted hydroxy and fluoroapatites have been studied. The hydroxy (CsLaSr3(PO4)3OH) and fluoro (CsLaSr3(PO4)3F) - lattices differ in accommodating rare earth ions. In the substitution of trivalent ions of Nd, Sm, Eu, Gd and Dy, hydroxy phase leads to the formation of pure apatite up to the substitution of Nd and Sm. Whereas, fluorapatite phase could accommodate Nd, Sm and Eu. Based on these results, mono, di and trivalent ions substituted apatite single phasic compositions of the formula CsLa0.8Nd0.1Sm0.1Sr3(PO4)3OH(CNSOH) and CsLa0.7Nd0.1Sm0.1Eu0.1Sr3(PO4)3F(CNSEF) have been fabricated. The leachability behavior of the phases is studied by carrying out MCC-5 test. (author)

  15. A novel glass ionomer cement containing MgCO(3 )apatite induced the increased proliferation and differentiation of human pulp cells in vitro.

    Science.gov (United States)

    Laiteerapong, Arunee; Lochaiwatana, Yossakit; Hirata, Isao; Okazaki, Masayuki; Mori, Kenta; Murakami, Shinya; Poolthong, Suchit

    2012-01-01

    This study aimed to investigate the in vitro biological response of human dental pulp cells to glass ionomer cement (GIC, Fuji IX GP(®)) containing 2.5% magnesium carbonate apatite (MgCO(3)Ap). MgCO(3)Ap was synthesized by wet method and characterized using FT-IR, XPS, and SEM. Fuji IX GP(®) served as a control. Test and control cements were prepared by encapsulated mixing the powder with Fuji IX-liquid (P/L=3.6:1). Eluates from cements extracted by 1 mL culture medium were collected at day 1, 7 and 14, and used for WST-1 proliferation assay. For ALPase activity, cells were maintained with cements in transwells, harvested and enzyme activity was measured at day 1, 4, 7, 14, and 21. We found a higher cell proliferation and increased ALPase activity by pulp cells in the test group compared to the control. This suggests the potential of GIC containing this novel biological apatite as a restorative material for pulp-dentin regeneration. PMID:23037840

  16. Comparative in vitro studies on disodium EDTA effect with and without Proteus mirabilis on the crystallization of carbonate apatite and struvite

    Science.gov (United States)

    Prywer, Jolanta; Olszynski, Marcin; Torzewska, Agnieszka; Mielniczek-Brzóska, Ewa

    2014-06-01

    Effect of disodium EDTA (salt of ethylenediamine tetraacetic acid) on the crystallization of struvite and carbonate apatite was studied. To evaluate such an effect we performed an experiment of struvite and carbonate apatite growth from artificial urine. The crystallization process was induced by Proteus mirabilis to mimic the real urinary tract infection, which usually leads to urinary stone formation. The results demonstrate that disodium EDTA exhibits the effect against P. mirabilis retarding the activity of urease - an enzyme produced by these microorganisms. The spectrophotometric results demonstrate that, with and without P. mirabilis, the addition of disodium EDTA increases the induction time and decreases the growth efficiency compared to the baseline (without disodium EDTA). These results are discussed from the standpoint of speciation of complexes formed in the solution of artificial urine in the presence of disodium EDTA. The size of struvite crystals was found to decrease in the presence of disodium EDTA. However, struvite crystals are larger in the presence of bacteria while the crystal morphology and habit remain unchanged.

  17. Influence of surface modification on the apatite formation and corrosion behavior of Ti and Ti-15Mo alloy for biomedical applications

    International Nuclear Information System (INIS)

    Commercially pure Ti and Ti-15Mo specimens were subjected to alkali-hydrogen peroxide and subsequent heat treatment to produce a nanoporous titanate gel layer with anatase phase. The surface morphology of the untreated, alkali-hydrogen peroxide treated and alkali-hydrogen peroxide heat treated specimens before and after 7 days of immersion in simulated body fluid was characterized using X-ray Diffractometer (XRD), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FT-IR). The formation of nanoporous titanate gel layer and the growth of apatite layer over the surface modified specimens after 7 days of immersion in simulated body fluid were confirmed. Further, the electrochemical corrosion behavior of all the specimens was examined using potentiodynamic polarization and electrochemical impedance spectroscopic techniques. - Highlights: ► Simple thermochemical process for Cp-Ti and Ti-15Mo alloy. ► Formation of nanoporous titanate layer on surface facilitate apatite formation. ► Hydroxyapatite coated sample exhibited improved corrosion resistance

  18. Crystallization of Apatites

    DEFF Research Database (Denmark)

    Ibsen, Casper Jon Steenberg

    2014-01-01

    består af både organiske og uorganiske elementer. Ved at organisere disse i en hierarkisk struktur, så opnår naturen egenskaber der er overlegne i forhold til de tilsvarende geologiske mineraler. Disse materialer kaldes for biomineraler. De kemiske processer, der ligger bag dannelsen af biomineraler...... krystaller fra opløsning er på trods af mange årtiers forskning stadig ikke fuldt forstået. Det har vist sig, at der for mange mineraler bliver dannet et amorft forstadie før omdannelsen til den krystallinske fase. Dette er især tilfældet for mange af de krystalsystemer, der findes i biologiske materialer...

  19. Determining the origin of enigmatic bedrock structures using apatite (U-Th)/He thermochronology: Alabama and Poverty Hills, Owens Valley, California

    Science.gov (United States)

    Ali, G. A.; Reiners, P. W.; Ducea, M.

    2008-12-01

    The Alabama and Poverty Hills are enigmatic, topographic highs of crystalline basement surrounded by Neogene sediments in Owens Valley, California. The 150-km long Owens Valley, the westernmost graben of the Basin and Range Province, initiated at about 3 Ma, creating ~2-4 km of vertical relief from the Sierra Nevada and White/Inyos crests to the valley floor. Along the valley, the active right-lateral Owens Valley Fault Zone (OVFZ) accommodates a significant portion of Pacific-North American plate motion, creating an oblique dextral fault zone, with localized transpression along minor left-stepovers. The dominantly granitic Mesozoic rocks of the Alabama Hills are bounded by the OVFZ to the east, and the granitic and metavolcanic Mesozoic rocks of the Poverty Hills are located along an apparent 3-km left stepover of the OVFZ. The tectonic origin and geodynamic significance of both these structures are not known, but previously published hypotheses include: 1) transpressional uplifts as OVFZ-related flower structures; 2) down-dropped normal fault blocks; and 3) giant landslides from adjacent ranges. We measured apatite (U-Th)/He ages on 15 samples from the Alabama and Poverty Hills to understand the history of shallow crustal exhumation of these structures, and to potentially correlate them to rocks from adjacent ranges. Apatite He dating typically yields cooling ages corresponding to closure temperatures of ~55-65 °C, corresponding roughly to depths of ~2-3 km in the crust. The majority of apatite He ages from the Alabama Hills ranged from 58-70 Ma, but the far eastern, and lowest elevation sample showed ages of 51-55 Ma. The Poverty Hills shows younger ages of 40-65 Ma and no recognizable spatial pattern. Although the data do not conclusively rule out a transpressional uplift origin of the Poverty Hills, the rocks within them could not have been exhumed from depths greater than ~2-3 km in Owens Valley. Data from both structures are most consistent with down

  20. Fe-O stable isotope pairs elucidate a high-temperature origin of Chilean iron oxide-apatite deposits

    Science.gov (United States)

    Bilenker, Laura D.; Simon, Adam C.; Reich, Martin; Lundstrom, Craig C.; Gajos, Norbert; Bindeman, Ilya; Barra, Fernando; Munizaga, Rodrigo

    2016-03-01

    Iron oxide-apatite (IOA) ore deposits occur globally and can host millions to billions of tons of Fe in addition to economic reserves of other metals such as rare earth elements, which are critical for the expected growth of technology and renewable energy resources. In this study, we pair the stable Fe and O isotope compositions of magnetite samples from several IOA deposits to constrain the source reservoir of these elements in IOAs. Since magnetite constitutes up to 90 modal% of many IOAs, identifying the source of Fe and O within the magnetite may elucidate high-temperature and/or lower-temperature processes responsible for their formation. Here, we focus on the world-class Los Colorados IOA in the Chilean iron belt (CIB), and present data for magnetite from other Fe oxide deposits in the CIB (El Laco, Mariela). We also report Fe and O isotopic values for other IOA deposits, including Mineville, New York (USA) and the type locale, Kiruna (Sweden). The ranges of Fe isotopic composition (δ56Fe, 56Fe/54Fe relative to IRMM-14) of magnetite from the Chilean deposits are: Los Colorados, δ56Fe (±2σ) = 0.08 ± 0.03‰ to 0.24 ± 0.08‰; El Laco, δ56Fe = 0.20 ± 0.03‰ to 0.53 ± 0.03‰; Mariela, δ56Fe = 0.13 ± 0.03‰. The O isotopic composition (δ18O, 18O/16O relative to VSMOW) of the same Chilean magnetite samples are: Los Colorados, δ18O (±2σ) = 1.92 ± 0.08‰ to 3.17 ± 0.03‰; El Laco, δ18O = 4.00 ± 0.10‰ to 4.34 ± 0.10‰; Mariela, δ18O = (1.48 ± 0.04‰). The δ18O and δ56Fe values for Kiruna magnetite yield an average of 1.76 ± 0.25‰ and 0.16 ± 0.07‰, respectively. The Fe and O isotope data from the Chilean IOAs fit unequivocally within the range of magnetite formed by high-temperature magmatic or magmatic-hydrothermal processes (i.e., δ56Fe 0.06-0.49‰ and δ18O = 1.0-4.5‰), consistent with a high-temperature origin for Chilean IOA deposits. Additionally, minimum formation temperatures calculated by using the measured Δ18O

  1. Resolving the chronology of the South African landscape through joint inverse modelling of AFT and apatite (U-Th)/He data

    Science.gov (United States)

    Wildman, Mark; Brown, Roderick; Beucher, Romain; Persano, Cristina; Stuart, Finlay

    2013-04-01

    Application of Low temperature thermochronometry (LTT) is a powerful method of constraining thermal history information on samples as they pass through isotherms in the upper crust. Inverse modelling of LTT data generates thermal history information which can then be correlated with independent datasets to infer geological processes that are responsible for producing the observed thermal history held in the thermochronometry record. A critical consideration when choosing which LTT method to use are the closure temperatures associated with each system. In order to generate more complete and robust thermal histories a single sample can be analysed using multiple low temperature thermochronometers that are sensitive over different but complimentary temperature ranges. The main focus of LTT work in South Africa has been on apatite fission track (AFT) analysis which is a world renowned method of constraining thermal history information between c. 60 and 110±10°C. The general conclusions that have been drawn from the South African AFT dataset is that the present day regional topography represents an eroded remnant of an elevated interior that experienced a significant uplift event with km-scale erosion in the Cretaceous following the break-up of Gondwana [1]. The exact nature of Cretaceous uplift and erosion varies both spatially and temporally, especially in south western Africa where at least two distinct denudation events are recorded at c. 130Ma and 90 Ma [2]. There are, however, alternative views suggesting significant epeirogenic-style uplift and subsequent erosion throughout the Cenozoic [3]. A key aspect of this debate which is yet to be fully resolved is the influence of mantle dynamics on the evolution of the overlying topography. To further investigate the timing and amount of Cenozoic uplift and erosion and to what degree this can be ascribed to dynamic topography, efforts have been made to complement the existing AFT record with Apatite (U-Th)/He analysis

  2. Low-temperature exhumation history of Variscan-age rocks in the western Cantabrian Mountains (NW Spain) recorded by apatite fission-track data

    Science.gov (United States)

    Grobe, René W.; Alvarez-Marrón, Joaquina; Glasmacher, Ulrich A.; Menéndez-Duarte, Rosana

    2010-06-01

    This paper presents the first regional study of apatite fission-track (AFT) thermochronology to be undertaken in the western termination of the Cantabrian Mountains (NW Spain). The mountains reach elevations of over 2600 m along the northern coast of Spain and are comprised of a Variscan crustal section uplifted due to Cenozoic shortening along the northern Iberian Plate. The study constrains the pattern and history of exhumation within the Paleozoic bedrock over the past c. 240 Ma. Twenty-one apatite fission-track samples range in age from 246.7 (± 26.9) Ma to 78.1 (± 3.7) Ma, with mean track lengths between 10.4 (± 1.8) µm and 12.4 (± 1.4) µm. Time-temperature path modelling of the data indicates that different rates of continuous cooling took place during the three main tectonic events that affected the area. A rapid cooling event that ended by the Late Jurassic corresponds to topographic decay during unroofing of the Variscan orogen and the break-up of Pangea, and is responsible for the largest amount of exhumation. Westernmost samples cooled coinciding with rifting in the North Atlantic and Bay of Biscay during the Late Jurassic to Early Cretaceous. By about 100-80 Ma most samples had reached, or passed through, the upper boundary of the apatite partial annealing zone, which indicate that regional denudation has not exceeded c. 1.7 km since then, for geothermal gradients ≥ 27 °C/km and a surface temperature of 15 °C. Only three samples next to fault escarpments in the west cooled below 70 °C since 80 Ma, reaching below 65 °C before initiation of incipient subduction along the northern Iberian Margin by 46 Ma. An average cooling rate of ≤ 1 °C/Ma reflects latest denudation as the new mountainous relief developed since then due to shortening and incipient subduction associated with convergence along the northern Iberian Plate. The Cantabrian Mountains are one of the few natural examples of a coastal orogen in a juvenile stage of evolution.

  3. Cenozoic evolution of tectono-fluid and metallogenic process in Lanping Basin,western Yunnan Province, Southwest China: Constraints from apatite fission track data

    Institute of Scientific and Technical Information of China (English)

    LI Xiaoming; SONG Yougui

    2006-01-01

    Since the Mesozoic, abundant metal and salt deposits have been formed in the Lanping Basin, western Yunnan Province, Southwest China, constituting a well-known hydrothermal ore belt in China. Most of the deposits are meso-epithermal hydrothermal deposits. This paper preliminarily deals with the mineralization ages of hydrothermal deposits in the Lanping Basin by using the apatite fission track method, and integrates the spatial distribution of the deposits and their regional geological backgrounds, to give the preliminary viewpoints as follows: (1) the apatite fission track ages acquired range from 19.9 Ma to 52.8 Ma, much younger than those of their host strata, so they may be considered to be mineralization ages, which represent the late mineralization period; (2) the apatite fission track ages tend to become younger from the west to the middle of the basin, indicating that the latest evolution of tectono-fluid and/or metallogenic processes of the middle basin ended later than that in the west; (3) in the Paleogene, most of the Cu deposits were formed in the western part of the basin; (4) the major metallogenic processes occur between the Paleogene and the Neogene, because the eastern and western edges of the basin were subducted into and collided with its bilateral continental blocks, respectively, and the central fault was strongly activated, which led to the processes of large-scale ore-forming fluids, and their differentiation and transport because of the variation of their physical and chemical properties. Having been squeezed and uplifted, the Lanping Basin became an intermontane basin that contains many kinds of fluid traps resulting in the formation of different types of ore deposits (for example, Pb-Zn, Cu, Ag) of different scales in the middle of the basin. Simultaneously, the fluids with volatile elements such as Hg, Sb and As were transported upwards along the central fault system and diffused into its subordinate fractures, thus leading to the

  4. Deciphering Past and Present Tectonics of the Rio Grande Rift in New Mexico Utilizing Apatite Fission Track Thermochronology, Geochronology, Quaternary Faulting, and Cross-Section Restoration

    Science.gov (United States)

    Ricketts, J. W.; Karlstrom, K. E.; Kelley, S. A.; Priewisch, A.; Crossey, L. J.; Asmerom, Y.; Polyak, V.; Selmi, M.

    2011-12-01

    The Rio Grande rift provides an excellent laboratory for understanding styles and processes of extensional tectonics, and their driving forces. We apply apatite fission track (AFT) thermochronology, geochronology, fracture analysis, and cross-section restoration to decipher past and present tectonics of the Rio Grande rift. AFT data has been compiled from rift flank uplifts along the Rio Grande rift in an attempt to recognize long wavelength spatial and temporal patterns. AFT ages record time of cooling of rocks below ~110°C and, when cooling is due to exhumation, age elevation traverses can record upward advection of rocks through paleo 110°C isotherms. The relatively passive sides of half-grabens (e.g. Manzanos and Santa Fe Range) preserve Laramide AFT ages ranging from 45-70 Ma, indicating they were cooled during the Laramide Orogeny and have remained cooler than 110°C since then. Rift flanks on the tectonically active sides of half-grabens, (e.g. Sierra Ladrones, Sandias, Taos Range, and Sierra Blanca) have AFT ages that range from 35 Ma to Mexico, indicates that it was rapidly unroofed between 20-10 Ma. Preliminary apatite helium data gives a similar age vs. elevation trend, but apatites have highly radiogenically damaged lattices and hence have corrected closure temperatures tens of degrees higher than AFT ages. The style of faulting at Ladron Peak is unusual because it is bounded by the anomalously low-angle (~15°) Jeter fault. In order to understand the evolution of faulting in this region, a balanced cross-section was constructed and restored to its pre-rift geometry. Our working hypothesis is that the low angle of the Jeter fault is most adequately explained by a rolling hinge model, where isostatic uplift causes progressive rotation of an initially steep (~60°) normal fault to shallower dips. Thirty km north of Ladron along the west side of the rift, Quaternary extensional faulting is evident in large travertine deposits at the Belen Quarry

  5. Preparation of an apatite-based matrix for the confinement of iodine 129; Mise au point d`une matrice apatitique pour le confinement de l`iode 129

    Energy Technology Data Exchange (ETDEWEB)

    Audubert, F.

    1995-11-08

    The aim of this thesis is the study of the conditioning of iodine 129 from the reprocessing of nuclear wastes. Because of its long half life (1.57 10{sup 7} years), the conditioning of iodine 129 requires a matrix stable during several thousands of years. The study of natural minerals allows the selection of mineral phases having a good long term behaviour. In the first part the policy of nuclear wastes management, and in particular of iodine, is recalled. A naturalistic approach is used to define the best conditioning material and the remarkable properties of apatite in this way are described. In the second part, the preparation and physical-chemical characterization of iodo-apatites are described. A demonstration is made that iodine can penetrate inside vanadate or lead phospho-vanadate apatite-based compounds. The third part deals with the preparation of the conditioning material. The sintering reaction under pressure allows the preparation of composite ceramics including iodo-apatite. A multi-layer coating process is defined: coating of PbI{sub 2} with a Pb{sub 3}(VO{sub 4}){sub 1.6}(PO{sub 4}){sub 0.4} layer and a Ca{sub 10}(PO{sub 4}){sub 6}F{sub 2} layer. Sintering is performed at 700 deg. celsius under a 25 MPa pressure. (J.S.). 131 refs.

  6. Framework 'interstitial' oxygen in La{sub 10}(GeO{sub 4}){sub 5{sup -}}(GeO{sub 5})O{sub 2} apatite electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Pramana, S.S.; White, T.J. [Nanyang Technological Univ., Singapore (Singapore). School of Materials Science and Engineering; Klooster, W.T. [Nanyang Technological Univ., Singapore (Singapore). School of Materials Science and Engineering; Institute of Materials Research and Engineering, Singapore (Singapore)

    2007-08-15

    Oxygen conduction at low temperatures in apatites make these materials potentially useful as electrolytes in solid-oxide fuel cells, but our understanding of the defect structures enabling ion migration is incomplete. While conduction along [001] channels is dominant, considerable inter-tunnel mobility has been recognized. Using neutron powder diffraction of stoichiometric 'La{sub 10}(GeO{sub 4}){sub 6}O{sub 3}', it has been shown that this compound is more correctly described as an La{sub 10}(GeO{sub 4}){sub 5-}(GeO{sub 5})O{sub 2} apatite, in which high concentrations of interstitial oxygen reside within the channel walls. It is suggested that these framework interstitial O atoms provide a reservoir of ions that can migrate into the conducting channels of apatite, via a mechanism of inter-tunnel oxygen diffusion that transiently converts GeO{sub 4} tetrahedra to GeO{sub 5} distorted trigonal bipyramids. This structural modification is consistent with known crystal chemistry and may occur generally in oxide apatites. (orig.)

  7. Titanite and apatite fission track analyses on basement rocks of central-southern Madagascar: constraints on exhumation and denudation rates along the eastern rift shoulder of the Morondava basin

    Science.gov (United States)

    Emmel, B.; Jacobs, J.; Razakamanana, T.

    2004-03-01

    Titanite and apatite fission-track (FT) thermochronology from basement rocks in central-southern Madagascar reveals a protracted post Late Neoproterozoic/Early Cambrian history of extensional tectonism, denudation and sedimentation. Titanite FT ages range between 379 ± 38 and 276 ± 17 Ma and apatite FT ages vary between 379 ± 19 and 150 ± 8 Ma. Combined titanite and apatite FT data from the western palaeo margin of Madagascar suggest denudation rates of ˜200-100 mMa -1 during Carboniferous times. The Late Neoproterozoic/Early Cambrian Ejeda shear zone was probably reactivated during this time. In contrast, for the same period denudation rates inland are ˜110-25 mMa -1. During Permo-Triassic rifting, areas that previously underwent fast denudation were buried by sedimentary cover up to ˜4.5 km. At this time, a graben developed along the transcontinental Bongolava-Ranotsara shear zone (BRSZ). Graben faults are exposed at the northeastern graben shoulder. Identical titanite and apatite FT ages close to the BRSZ indicate rapid cooling associated with fluid circulation during Early Permian times. The initial Gondwana break-up during Middle Jurassic times and the drift of Madagascar along the Davie transform fault did not significantly influence the FT data and had only minor geomorphic impact in the study area. Only the far southwestern part of the island is characterised by a higher degree of denudation (max. ˜3.5 km) during Early Jurassic times. Early Cretaceous and Cenozoic volcanic activity affected the apatite FT data from southern Madagascar. Modelled time-temperature ( T- t) paths argue for a reheating of samples from southern Madagascar to temperatures of ˜60-80 °C during the times of magmatism, before final cooling to surface temperatures.

  8. Porous SiO2 nanofiber grafted novel bioactive glass-ceramic coating: A structural scaffold for uniform apatite precipitation and oriented cell proliferation on inert implant.

    Science.gov (United States)

    Das, Indranee; De, Goutam; Hupa, Leena; Vallittu, Pekka K

    2016-05-01

    A composite bioactive glass-ceramic coating grafted with porous silica nanofibers was fabricated on inert glass to provide a structural scaffold favoring uniform apatite precipitation and oriented cell proliferation. The coating surfaces were investigated thoroughly before and after immersion in simulated body fluid. In addition, the proliferation behavior of fibroblast cells on the surface was observed for several culture times. The nanofibrous exterior of this composite bioactive coating facilitated homogeneous growth of flake-like carbonated hydroxyapatite layer within a short period of immersion. Moreover, the embedded porous silica nanofibers enhanced hydrophilicity which is required for proper cell adhesion on the surface. The cells proliferated well following a particular orientation on the entire coating by the assistance of nanofibrous scaffold-like structural matrix. This newly engineered composite coating was effective in creating a biological structural matrix favorable for homogeneous precipitation of calcium phosphate, and organized cell growth on the inert glass surface. PMID:26952416

  9. Tectonomorphic evolution of the Eastern Cordillera fold-thrust belt, Colombia: New insights based on apatite and zircon (U-Th)/He thermochronometers

    Science.gov (United States)

    Ghorbal, B.; Stockli, D. F.; Mora, A.; Horton, B. K.; Blanco, V.; Sanchez, N.

    2010-12-01

    The Eastern Cordillera (EC) of Colombia marks the eastern boundary of Cenozoic fold-thrust deformation in the northern Andes. It is a classic example of an inversion belt formed in the retro-arc region, in this case superimposed on a Triassic/Jurassic to Cretaceous intracontinental rift system of northern South America. Ongoing thrust reactivation (inversion) in this contractional orogen provides an excellent opportunity to study the patterns of deformation and influence of preexisting anisotropies (Mora et al., 2006). The objective of this detailed (U-Th)/He study is to unravel the tectonic and thermal evolution of the EC from the Magdalena Valley basin in the west to the Llanos foreland basin in the east and reconstruct the temporal and spatial progression of deformation in the EC fold-thrust belt. Furthermore, the Subandean or foothills zone of Colombia is key for understanding the petroleum systems in the complex frontal zone of the inverted fold-thrust belt. We present detailed apatite and zircon (U-Th)/He thermochronometric data from surface samples along a ~220 km WNW-ESE transect across the EC from the frontal fold-thrust belt at the edge of the Llanos basin to the western edge of the EC, the Magdalena basin. Surface and borehole zircon and apatite (U-Th)/He data, integrated with structural data, show that the EC fold-thrust belt propagated foreland-ward from the axial zone to the modern edges of the fold-thrust belt from at least the early Oligocene to the early Miocene. Detailed apatite and zircon (U-Th)/He data from surface samples and borehole samples in the foothills-Llanos transition zone and the Middle Magdalena Valley basin, between the large-displacement Guaicaramo and Pajarito-Chámeza thrusts in the east and the La Salina fault system in the west show a temporally complex evolution. The frontal fold-thrust belt was characterized by continued progressive foreland-ward migration of deformation and an apparent phase of major out-of-sequence motion

  10. FIELD TEST INSTRUCTION 100-NR-2 OPERABLE UNIT DESIGN OPTIMIZATION STUDY FOR SEQUESTRATION OF SR-90 SATURATED ZONE APATITE PERMEABLE REACTIVE BARRIER EXTENSION

    Energy Technology Data Exchange (ETDEWEB)

    BOWLES NA

    2010-10-06

    The objective of this field test instruction is to provide technical guidance for aqueous injection emplacement of an extension apatite permeable reactive barrier (PRE) for the sequestration of strontium-90 (Sr-90) using a high concentration amendment formulation. These field activities will be conducted according to the guidelines established in DOE/RL-2010-29, 100-NR-2 Design Optimization Study, hereafter referred to as the DOS. The DOS supports the Federal Facility Agreement Consent Order (EPA et al., 1989), Milestone M-16-06-01, and 'Complete Construction of a Permeable Reactive Barrier at 100-N.' Injections of apatite precursor chemicals will occur at an equal distance intervals on each end of the existing PRE to extend the PRB from the existing 91 m (300 ft) to at least 274 m (900 ft). Field testing at the 100-N Area Apatite Treatability Test Site, as depicted on Figure 1, shows that the barrier is categorized by two general hydrologic conceptual models based on overall well capacity and contrast between the Hanford and Ringold hydraulic conductivities. The upstream portion of the original barrier, shown on Figure 1, is characterized by relatively low overall well specific capacity. This is estimated from well development data and a lower contrast in hydraulic conductivity between the Hanford formation and Ringold Formations. Comparison of test results from these two locations indicate that permeability contrast between the Hanford formation and Ringold Formation is significantly less over the upstream one-third of the barrier. The estimated hydraulic conductivity for the Hanford formation and Ringold Formation over the upstream portion of the barrier based on observations during emplacement of the existing 91 m (300 ft) PRB is approximately 12 and 10 m/day (39 and 32 ft/day), respectively (PNNL-17429). However, these estimates should be used as a rough guideline only, as significant variability in hydraulic conductivity is likely to be observed in

  11. Long-term landscape evolution of the South Atlantic "passive" continental margin in Eastern Argentina using apatite fission-track thermochronology

    Science.gov (United States)

    Pfister, Sabrina; Kollenz, Sebastian; Glasmacher, Ulrich A.

    2015-04-01

    To understand the evolution of the "passive" continental margin in Argentina low temperature thermochronology is an appropriate method, which might lead to new insights in this area. The Tandilia System, also called Sierras Septentrionales, is located south of the Río de la Plato Craton in eastern Argentina in the state of Buenos Aires. North of the hills the Salado basin is located whereas the Claromecó basin is situated south of the mountain range. In contrary to most basins along the South American "passive" continental margin, the Tandilia-System and the neighbouring basins trend perpendicular to the coast line. The topography is fairly flat with altitudes up to 350 m. The igneous-metamorphic basement is pre-Proterozoic in age and build up of mainly granitic-tonalitic gneisses, migmatites, amphibolites, some ultramafic rocks and granitoid plutons. It is overlain by a series of Neoproterozoic to early Paleozoic sedimentary rocks (Cingolani 2011), like siliciclastic rocks, dolostones, shales and limestones (Demoulin 2005). The aim of the study is to quantify the long-term landscape evolution of the "passive" continental margin in eastern Argentina in terms of thermal, exhumation and tectonic evolution. For that purpose, samples were taken from the basement of the Sierra Septentrionales and analyzed with the apatite fission-track method. Further 2-D thermokinematic modeling was conducted with the computer code HeFTy (Ketcham 2005; Ketcham 2007; Ketcham et al. 2009). Because there are different hypotheses in literature regarding the geological evolution of this area two different models were generated, one after Demoulin et al. (2005) and another after Zalba et al.(2007). All samples were taken from the Neoproterozoic igneous-metamorphic basement. Apatite fission-track ages range from 101.6 (9.4) to 228.9 (22.3) Ma, and, therefore, are younger than their formation age, indicating all samples have been thermally reset. Six samples accomplished enough confined

  12. Apatite (U-Th)/He Thermochronometry as an innovative Geothermal Exploration Tool - A case study from the Wassuk Range, Hawthorne, Nevada

    Science.gov (United States)

    Gorynski, K. E.; Stockli, D. F.; Walker, J. D.

    2010-12-01

    A utility-grade geothermal system requires increased, near-surface temperatures (>120°C), water to transfer heat, and structural or sedimentological fluid conduits. In extensional tectonic settings, geothermal anomalies often occur in areas with recent, high strain accumulation and complex faulting (i.e., cross-faults, accommodation zones) where exhumation and uplift of footwall rocks transfer heat, via advection, to the near-surface which is further carried by water through structural fluid conduits. Apatite helium (AHe) thermochronometric footwall age mapping can be used in conjunction with these genetic occurrence models to further focus regional-scale geothermal exploration efforts to areas of probabilistic increased fracture permeability and most recent, rapid footwall exhumation. Furthermore, partially reset apatites resulting from interaction with hydrothermal fluids (>40°C) will show which areas have been hottest most recently. This case study in the Wassuk Range, Hawthrone, NV confirms the utility of AHe thermochronometry as a geothermal exploration tool. A dense grid of footwall samples were collected adjacent to the Hawthorne geothermal anomaly (>85°C BHT) located in the hanging wall of the Wassuk Range block. Our data show that the location of the present-day geothermal anomaly correlates with the location of 1) the most recent episode of rapid footwall exhumation at 3.5-4 Ma, 2) km scale accommodation zones between differentially tilted Wassuk Range blocks, and 3) an elevated Miocene geothermal gradient. Furthermore, anomalously young AHe ages (Hawthorne geothermal anomaly and likely resulted from interaction with a deep-seated geothermal cell or hot hydrothermal fluids.

  13. Multi-phase Uplift of the Indo-Burman Ranges and Western Thrust Belt of Minbu Sub-basin (West Myanmar): Constraints from Apatite Fission Track Data

    Science.gov (United States)

    Zhang, P.; Qiu, H.; Mei, L.

    2015-12-01

    The forearc regions in active continental margins are important keys to analysis geodynamic processes such as oceanic crust oblique subduction, mechanism of subduction zone, and sediments recycling. The West Myanmar, interpreted as forearc silver, is the archetype example of such forearc regions subordinate to Sunda arc-trench system, and is widely debated when and how its forearc regions formed. A total of twenty-two samples were obtained from the Indo-Burman Ranges and western thrust belt of Minbu Sub-basin along Taungup-Prome Road in Southwestern Myanmar (Figure 1), and five sandstone samples of them were performed at Apatite to Zircon, Inc. Three samples (M3, M5, and M11) collected from Eocene flysch and metamorphic core at the Indo-Burman Ranges revealed apatite fission track (AFT) ages ranging from 19 to 9 Ma and 6.5 to 2 Ma. Two samples (M20 and M21) acquired from the western thrust belt of Minbu Sub-basin yielded AFT ages ranging from 28 to 13.5 Ma and 7.5 to 3.5 Ma. Time-temperature models based on AFT data suggest four major Cenozoic cooling episodes, Late Oligocene, Early to Middle Miocene, Late Miocene, and Pliocene to Pleistocene. The first to third episode, models suggest the metamorphic core of the Indo-Burman Ranges has experienced multi-phase rapidly uplifted during the early construction of the forearc regions. The latest episode, on which this study focused, indicated a fast westward growth of the Palaeogene accretionary wedge and a eastward propagation deformation of folding and thrusting of the western thrust belt of Minbu Sub-basin. We argued that above multi-phase uplifted and deformation of the forearc regions were results of India/West Burma plate's faster oblique convergence and faster sedimentation along the India/Eurasia suture zone.

  14. The interaction between cations and anionic groups inducing SHG enhancement in a series of apatite-like crystals: A first-principles study

    International Nuclear Information System (INIS)

    It is an interesting topic to reveal the origin of the SHG intensity enhancement after substitution from alkali and alkali-earth metal atoms to cadmium in a series of apatite-like borates KSr4(BO3)3, Ca5(BO3)3F, Cd5(BO3)3F. Combined with the first-principles method, SHG-density method and real-space atom-cutting method, the electronic structure, the optical properties and the contribution of respective ion and ion groups have been investigated. Second harmonic generation (SHG) responses are mainly attributed to BO3 groups with π conjugated configuration and their alignment framework. The contributions of A site are more important in CaBOF and CdBOF compounds than in KSrBO. It is also demonstrated that the strong covalent interactions between the boron–oxygen groups and the cadmium atoms contribute the enhancement of SHG responses after substitution from alkali and alkali-earth metal atoms. - graphical abstract: Combined with the first-principles method, SHG-density method and real-space atom-cutting method, the enhancement of SHG response are attributed to the interaction between cadmium and BO3 groups. - Highlights: • SHG response on a series of apatite-like borates was studied by a SHG-density method. • SHG responses are mainly attributed to BO3 groups and their alignment framework. • The contributions of A site are more important in CaBOF and CdBOF than in KSrBO. • Covalent interaction between BO and Cd is responsible for SHG of CdBOF

  15. In Vitro Screening of the Apatite-Forming Ability, Biointeractivity and Physical Properties of a Tricalcium Silicate Material for Endodontics and Restorative Dentistry

    Directory of Open Access Journals (Sweden)

    Maria Giovanna Gandolfi

    2013-12-01

    Full Text Available Aim: Calcium silicate-based materials are hydraulic self-setting materials with physico-chemical properties suitable for endodontic surgery and good biological/clinical outcomes. The study aim was to evaluate the bio-properties (biointeractivity and apatite-forming ability and selected physical properties (porosity, water sorption, solubility, and setting time of Biodentine, a tricalcium silicate material for endodontics and restorative dentistry, compared to that of ProRoot MTA (Mineral Trioxide Aggregate as gold standard material. Methods: Biodentine and ProRoot MTA pastes were prepared and analyzed for calcium release and alkalinizing activity (3 h–28 days, setting time, water sorption, porosity, solubility, surface microstructure and composition, and apatite-forming ability in simulated body fluid. Results: Biodentine showed higher calcium release, alkalinizing activity, and solubility but higher open and apparent porosity, water sorption, and a markedly shorter setting time. Calcium phosphate (CaP deposits were noted on material surfaces after short ageing times. A CaP coating composed of spherulites was detected after 28 days. The thickness, continuity, and Ca/P ratio of the coating differed markedly between the materials. Biodentine showed a coating composed by denser but smaller spherulites, while ProRoot MTA showed large but less dense aggregates of spherulitic deposits. Conclusions: Biodentine showed a pronounced ability to release calcium and extended alkalinizing activity interlinked with its noticeable porosity, water sorption, and solubility: open porosities provide a broad wet biointeractive surface for the release of the calcium and hydroxyl ions involved in the formation of a CaP mineral. Biodentine is a biointeractive tricalcium silicate material with interesting chemical-physical properties and represents a fast-setting alternative to the conventional calcium silicate MTA-like cements.

  16. Natural age dispersion arising from the analysis of broken crystals. Part I: Theoretical basis and implications for the apatite (U-Th)/He thermochronometer

    Science.gov (United States)

    Brown, Roderick W.; Beucher, Romain; Roper, Steven; Persano, Cristina; Stuart, Fin; Fitzgerald, Paul

    2013-12-01

    Over the last decade major progress has been made in developing both the theoretical and practical aspects of apatite (U-Th)/He thermochronometry and it is now standard practice, and generally seen as best practice, to analyse single grain aliquots. These individual prismatic crystals are often broken and are fragments of larger crystals that have broken during mineral separation along the weak basal cleavage in apatite. This is clearly indicated by the common occurrence of only 1 or no clear crystal terminations present on separated apatite grains, and evidence of freshly broken ends when grains are viewed using a scanning electron microscope. This matters because if the 4He distribution within the whole grain is not homogeneous, because of partial loss due to thermal diffusion for example, then the fragments will all yield ages different from each other and from the whole grain age. Here we use a numerical model with a finite cylinder geometry to approximate 4He ingrowth and thermal diffusion within hexagonal prismatic apatite crystals. This is used to quantify the amount and patterns of inherent, natural age dispersion that arises from analysing broken crystals. A series of systematic numerical experiments were conducted to explore and quantify the pattern and behaviour of this source of dispersion using a set of 5 simple thermal histories that represent a range of plausible geological scenarios. In addition some more complex numerical experiments were run to investigate the pattern and behaviour of grain dispersion seen in several real data sets. The results indicate that natural dispersion of a set of single fragment ages (defined as the range divided by the mean) arising from fragmentation alone varies from c. 7% even for rapid (c. 10 °C/Ma), monotonic cooling to over 50% for protracted, complex histories that cause significant diffusional loss of 4He. The magnitude of dispersion arising from fragmentation scales with the grain cylindrical radius, and is of

  17. Experimental study of kinetic and mechanism of dissolution of apatite structured minerals. Application to the prediction of the long term behavior of an actinides storage host matrix; Etude experimentale de la cinetique et des mecanismes d'alteration de mineraux apatitiques. Application au comportement d'une ceramique de confinement d'actinides mineurs

    Energy Technology Data Exchange (ETDEWEB)

    Chairat, C

    2005-11-15

    The motivation for this study is to assess the potential of using apatite structured ceramics as long-lived actinide storage hosts. To assess their ability to resist aqueous corrosion, the dissolution of natural fluoro-apatite and synthetic Nd-britholite (neodymium is a proxy for the trivalent actinides) was studied. Mineral surfaces were characterized using a combined spectrometric, electrokinetic and potentiometric approach and dissolution rates were measured in closed and open system reactors as a function of solution composition. Experimental results suggest apatitic minerals dissolve via distinct step sequence: 1) fluoride release, 2) release of the calcium situated in the M1, and 3) the simultaneous removal of phosphate and calcium II via the breaking of only Ca-O bonds. TST based rate equations based in this mechanism accurately describe fluoro-apatite and synthetic britholite dissolution rates as a function of solution composition. Nd release rates are limited by precipitation of Nd-rhabdophane. (author)

  18. New constraints on paleo-denudation history of the Ladakh Batholith - applying bedrock and detrital apatite (U-Th-Sm)/He thermochronology

    Science.gov (United States)

    Sahragard Sohi, Mohammad; Rosenkranz, Ruben; Spiegel, Cornelia

    2015-04-01

    The Ladakh Batholith is part of the Transhimalayan Plutonic Belt and records the early exhumation history of the Himalayan orogen. The evolution of the Ladakh Batholith is complex and was controversially discussed in the literature (see Kirstein, 2011 for details). Recent data by Kirstein et al. (2006 & 2009) suggest a trend of exhumation rates across the batholith, with earlier exhumation along its southern margin and later exhumation in the north. Apart from methodological purpose aimed at refining the apatite (U-Th-Sm)/He technique, the goal of our study is to investigate the earliest denudation history of the Ladakh Pluton and thereby that of the Himalayan orogen, using apatite (U-Th-Sm)/He thermochronology (i) applied to bedrocks from the southern margin of the batholith, and (ii) to sediments from the adjacent Upper Indian Group sediments such as Nurla, Choksti, and Nimu Formations with Early Eocene to Late Miocene in age (Henderson et al., 2010). These sediments are thought to be sourced from the Ladakh Batholith (Henderson et al., 2011). Apatite (U-Th-Sm)/He dating is sensitive to temperatures between ~85 and 40°C and thus to geodynamic movements of the upper ~1.5 to 3 km of the earth's crust. While thermochronology data from present-day bedrock exposures provides denudation rates integrated over the time between cooling age and the present, the earlier denudation history is eroded away from the present exposures and stored in the syn-tectonic sediments. Thus, dating sediments of the Indian Group will yield the paleo-denudation history of the (southern) Ladakh area, including changes of denudation rates back through time. This will reveal new insights into the relation between tectonics, climate, and erosion. References Henderson, A. L., Y. Najman, R. Parrish, M. BouDagher - Fadel, D. Barford, E. Garzanti, and S. Andò (2010), Geology of the Cenozoic Indus Basin sedimentary rocks: Paleoenvironmental interpretation of sedimentation from the western Himalaya

  19. Origin and evolution of ore-forming fluids in the Hemushan magnetite-apatite deposit, Anhui Province, Eastern China, and their metallogenic significance

    Science.gov (United States)

    Luo, Gan; Zhang, Zhiyu; Du, Yangsong; Pang, Zhenshan; Zhang, Yanwen; Jiang, Yongwei

    2015-12-01

    The Middle-Lower Yangtze River Metallogenic Belt in the northern Yangtze Block is one of the most important economic mineral districts in China. The Hemushan deposit is a medium-class Fe deposit located in the southern part of the Ningwu iron ore district of the Middle-Lower Yangtze River Metallogenic Belt. The Fe-orebodies are mainly hosted in the contact zone between diorite and Triassic marble. The actinolite-phlogopite-apatite-magnetite ore shows metasomatic/filling textures and disseminated/mesh-vein structures. Based on evidences and petrographic observations, the ore-forming process can be divided into three distinct periods-the early metallogenic period (albite-diopside stage), the middle metallogenic period (magnetite stage and hematite stage), and the late metallogenic period (quartz-pyrite stage and carbonate stage). Fluid inclusion studies show four types of inclusions: type I daughter mineral-bearing three-phase inclusions (L + V + S), type II vapor-rich two-phase inclusions (L + V), type III liquid-rich two phase inclusions (L + V), and minor type IV liquid-phase inclusions (L). Apatites from the magnetite stage contain type I, type II and type III inclusions; anhydrites from the hematite stage mainly contain abundant type II inclusions and relatively less type I inclusions; quartz and calcite from the late metallogenic stage are mainly characterized by type III inclusions. Laser Raman spectroscopy and microthermometry of fluid inclusions show that the ore-forming fluids broadly correspond to unsaturated NaCl-H2O system. From the magnetite stage to the carbonate stage, the ore-forming fluids evolved from moderate-high temperature (average 414 °C), moderate salinity (average 25.01 wt.% NaCl equiv.) conditions to low temperature (average 168 °C), low salinity (average 6.18 wt.% NaCl equiv.) conditions. Hydrogen and oxygen isotopic studies indicate that the ore-forming fluid during the early stage of middle metallogenic period was mainly of magmatic

  20. Adsorption of Pb(II) present in aqueous solution on calcium, strontium and barium hydroxy apatites; Adsorcion de Pb(II) presente en solucion acuosa sobre hidroxiapatitas de calcio, estroncio y bario

    Energy Technology Data Exchange (ETDEWEB)

    Vilchis G, J.

    2013-07-01

    Calcium, strontium and barium hydroxy apatites were successfully synthesized by chemical precipitation method, the obtained powders were characterized by the techniques of X-ray diffraction (XRD), scanning electron microscopy (Sem), semi-quantitative elemental analysis (EDS), infrared spectroscopy (IR), and N{sub 2} physisorption studies, complementary to these analytical techniques, was determined the surface fractal dimension (Df), and the amount of surface active sites of the materials, in order to know application as ceramic for water remediation. The ability of Pb(II) ion adsorption present in aqueous solution on the hydroxy apatites synthesized by batch type experiments was studied as a function of contact time, concentration of the adsorbate and temperature. The maximum lead adsorption efficiencies obtained were 0.31, 0.32 and 0.26 mg/g for calcium, strontium and barium hydroxy apatites respectively, achieved an equilibrium time of 20 minutes in the three solid-liquid systems studied. Experimental data were adequately adjusted at the adsorption kinetic model pseudo-second order, for the three cases. Moreover, experimental data of the strontium and calcium hydroxy apatites were adjusted to the Langmuir adsorption isotherm, indicating that the adsorption was through a monolayer, whereas barium hydroxyapatite was adjusted to the Freundlich adsorption isotherm, indicating a multilayer adsorption. The thermodynamic parameters obtained during adsorption studies as a function of temperature showed physisorption, exothermic and spontaneous processes respectively. The results showed that the calcium hydroxyapatite, strontium and barium are an alternative for the Pb(II) ion adsorption present in wastewaters. (Author)

  1. Thermal history and age of geological regions obtained by applying the fission track method in apatite samples; Historia termica e idades de regioes geologicas obtidas atraves de tracos de fissao em apatita

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Cleber J.; Tello Saenz, Carlos A.; Balan, Ana M. Osorio A.; Dias, Airton N.C.; Novaes, Felipe P.; Oliveira, Roger D.; Barra, Beatriz C., E-mail: pccj13@yahoo.com.b, E-mail: amoa@fct.unesp.b [UNESP, Presidente Prudente, SP (Brazil). Dept. de Fisica, Quimica e Biologia

    2007-07-01

    The objective of this work is dating apatite samples using the Fission Track Method (FTM). Samples were collected from different altitudes in Serra da Mantiqueira (Brazil): High Mantiqueira (above 1,000 m) and Low Mantiqueira (below 1,000 m). Data obtained for the ages and thermal history of the samples via FTM have been interpreted and, according to the geological point of view, can be associated with the uplifting of Serra da Mantiqueira after the opening of the Atlantic Ocean

  2. High resolution rare-earth elements analyses of natural apatite and its application in geo-sciences: Combined micro-PIXE, quantitative CL spectroscopy and electron spin resonance analyses

    International Nuclear Information System (INIS)

    The rare-earth element (REE) distribution in natural apatite is analysed by micro-PIXE, cathodoluminescence (CL) microscopy and spectroscopy and electron spin resonance (ESR) spectroscopy. The micro-PIXE analyses of an apatite crystal from Cerro de Mercado (Mexico) and the summary of 20 analyses of six francolite (conodonts of Triassic age) samples indicate that most of the REEs are enriched in apatite and francolite comparative to average shale standard (NASC). The analyses of fossil francolite revealing the REE-distribution not to be in balance with the REE-distribution of seawater and fish bone debris. Strong inhomogenous lateral REE-distribution in fossil conodont material is shown by CL-mapping and most probably not being a vital effect. Therefore, the resulting REE-signal from fossil francolite is the sum of vital and post-mortem incorporation. The necessary charge compensation for the substitution of divalent Ca by trivalent REE being done by different kind of electron defects and defect ions

  3. Thermal history from Pocos de Caldas alkaline massif, SP/MG , Brazil and dyke rich margins using apatite fission track analysis

    International Nuclear Information System (INIS)

    The South American Platform in southeastern Brazil records a long history of tectonic magmatic and uplift events, which resulted from the opening of the South Atlantic Ocean, Cretaceous reactivation and epirogeneic processes. Specific manifestations include the basic magmatism of the Serra Geral Formation of the Parana Basin and alkaline magmatism of Pocos de Caldas - Cabo Frio Lineament, as well as the uplift of the Serra da Mantiqueira and Serra do Mar mountain ranges. Thermo tectonic and geochronological studies using the K-Ar method and apatite fission track analysis in samples of the Pocos de Caldas alkaline massif show an initial evolution beginning 89 Ma related to a tectonic uplift, interpreted as related to the intrusion's doming. This was followed by an important episode of rapid cooling related to the formation of the massif. At the same time, the mountains that surround the massif record heating events in response to the alkaline intrusion, between 70 and 50 Ma. Periods of slow uplift, probably related to the South American Erosion Cycle (between 50 and 30 Ma) and Velhas Erosion Cycle (from 25 Ma), indicate a strong manifestation of denudation in this area. (author)

  4. Crystal structure of apatite type Ca2.49Nd7.51(SiO4)6O1.75.

    Science.gov (United States)

    Le, Thu Hoai; Brooks, Neil R; Binnemans, Koen; Blanpain, Bart; Guo, Muxing; Van Meervelt, Luc

    2016-02-01

    The title compound, Ca2+x Nd8-x (SiO4)6O2-0.5x (x = 0.49), was synthesized at 1873 K and rapidly quenched to room temperature. Its structure has been determined using single-crystal X-ray diffraction and compared with results reported using neutron and X-ray powder diffraction from samples prepared by slow cooling. The single-crystal structure from room temperature data was found to belong to the space group P63/m and has the composition Ca2.49Nd7.51(SiO4)6O1.75 [dicalcium octa-neodymium hexa-kis-(ortho-silicate) dioxide], being isotypic with natural apatite and the previously reported Ca2Nd8(SiO4)6O2 and Ca2.2Nd7.8(SiO4)6O1.9. The solubility limit of calcium in the equilibrium state at 1873 K was found to occur at a composition of Ca2+x Nd8-x (SiO4)6O2-0.5x , where x = 0.49. PMID:26958389

  5. Thermal history of the Jurassic Strata in the Northern Tianshan and its geological significance, revealed by apatite fission-track and vitrinite-reflectance analysis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z.C.; Guo, Z.J.; Wu, C.D.; Fang, S.H. [Peking University, Beijing (China)

    2007-07-15

    Apatite fission track (AFT) dating is carried on 18 samples collected from Shichang-Manas, Anjihai river and Sikesu area of the Northern margin of Tianshan. Vitrinite reflectance (R{sub o}) data of 10 samples from the Triassic to Jurassic coal seam were obtained to provide maximum paleotemperatures for the stratigraphic strata experiencing. The data suggest that maximum burial and thermal maturity of the Triassic and lower Jurassic rocks occurred at Late Jurassic to Early Cretaceous, and then retained at the same depth till Miocene. This history is consistent with the AFT modeling result of the underlying granite. The cooling of Late Jurassic to Early Cretaceous can be typically interpreted as the result of decreasing of paleothermal gradient at the Cretaceous. The burial and heating of the Middle Jurassic rocks preserved for a long time until late Oligocene. All AFT samples show evidence for Miocene rapid cooling, beginning at about 10 Ma. This cooling is typically interpreted as the result of uplift and erosion of overlying strata. Miocene cooling of Mesozoic and Paleozoic granite suggests that uplift of the northern Tianshan occurred significantly later than previously proposed and is consistent with timing of intense deformation in the southwestern Junggar basin.

  6. Electronic structure, elastic anisotropy, thermal conductivity and optical properties of calcium apatite Ca5(PO4)3X (X = F, Cl or Br)

    International Nuclear Information System (INIS)

    Highlights: • The degree of elastic anisotropy is ordered as follows BrA > ClA > FA. • The thermal conductivity in (112¯0) plane is smaller than in (0 0 0 1) plane. • The refractive indexes for FA, ClA and BrA are 1.17, 1.19 and 1.21, respectively. - Abstract: The density-functional theory with the generalized gradient approximation was performed to investigate the structural properties, phase stability, electronic structure, elastic properties, and optical properties of selected Ca5(PO3)4F (FA), Ca5(PO3)4Cl (ClA) and Ca5(PO3)4Br (BrA). Results of formation enthalpies show that FA is regarded as the most stable one in these apatites. The electronic structures including band structure, density of states and Mulliken analysis have been discussed. The predicted elastic moduli results indicate that the degree of elastic anisotropy is ordered as follows BrA > ClA > FA. By using the Clarke’s model and Cahill’s model, the thermal conductivities and the anisotropy in thermal conductivity have also been analyzed. Optic properties results indicate that the refractive indexes n for FA, ClA and BrA are 1.17, 1.19 and 1.21, respectively

  7. Electronic structure, elastic anisotropy, thermal conductivity and optical properties of calcium apatite Ca{sub 5}(PO{sub 4}){sub 3}X (X = F, Cl or Br)

    Energy Technology Data Exchange (ETDEWEB)

    Li, Cheng-Xiu [Kunming University of Science and Technology, Kunming 650093 (China); Institute of Multipurpose Utilization of Mineral Resources, Chinese Academy of Geological Sciences, Chengdu 610041 (China); Research Center of Multipurpose Utilization of Metal Mineral Resources of China Geological Survey, Chengdu 610041 (China); Duan, Yong-Hua, E-mail: duanyh@kmust.edu.cn [Kunming University of Science and Technology, Kunming 650093 (China); Hu, Wen-Cheng [School of Mechanical and Electrical Engineering, Nanchang University, Nanchang 330031 (China)

    2015-01-15

    Highlights: • The degree of elastic anisotropy is ordered as follows BrA > ClA > FA. • The thermal conductivity in (112{sup ¯}0) plane is smaller than in (0 0 0 1) plane. • The refractive indexes for FA, ClA and BrA are 1.17, 1.19 and 1.21, respectively. - Abstract: The density-functional theory with the generalized gradient approximation was performed to investigate the structural properties, phase stability, electronic structure, elastic properties, and optical properties of selected Ca{sub 5}(PO{sub 3}){sub 4}F (FA), Ca{sub 5}(PO{sub 3}){sub 4}Cl (ClA) and Ca{sub 5}(PO{sub 3}){sub 4}Br (BrA). Results of formation enthalpies show that FA is regarded as the most stable one in these apatites. The electronic structures including band structure, density of states and Mulliken analysis have been discussed. The predicted elastic moduli results indicate that the degree of elastic anisotropy is ordered as follows BrA > ClA > FA. By using the Clarke’s model and Cahill’s model, the thermal conductivities and the anisotropy in thermal conductivity have also been analyzed. Optic properties results indicate that the refractive indexes n for FA, ClA and BrA are 1.17, 1.19 and 1.21, respectively.

  8. Effects of Apatite Cement Containing Atelocollagen on Attachment to and Proliferation and Differentiation of MC3T3-E1 Osteoblastic Cells

    Directory of Open Access Journals (Sweden)

    Masaaki Takechi

    2016-04-01

    Full Text Available To improve the osteoconductivity of apatite cement (AC for reconstruction of bone defects after oral maxillofacial surgery, we previously fabricated AC containing atelocollagen (AC(ate. In the present study, we examined the initial attachment, proliferation and differentiation of mouse osteoblastic cells (MC3T3-E1 cells on the surface of conventional AC (c-AC, AC(ate and a plastic cell dish. The number of osteoblastic cells showing initial attachment to AC(ate was greater than those attached to c-AC and similar to the number attached to the plastic cell wells. We also found that osteoblastic cells were well spread and increased their number on AC(ate in comparison with c-AC and the wells without specimens, while the amount of procollagen type I carboxy-terminal peptide (PIPC produced in osteoblastic cells after three days on AC(ate was greater as compared to the others. There was no significant difference in regard to alkaline phosphatase (ALP activity and osteocalcin production by osteoblastic cells among the three surface types after three and six days. However, after 12 days, ALP activity and the produced osteocalcin were greater with AC(ate. In conclusion, AC(ate may be a useful material with high osteoconductivity for reconstruction of bone defects after oral maxillofacial surgery.

  9. Crystal structure of apatite type Ca2.49Nd7.51(SiO46O1.75

    Directory of Open Access Journals (Sweden)

    Thu Hoai Le

    2016-02-01

    Full Text Available The title compound, Ca2+xNd8–x(SiO46O2–0.5x (x = 0.49, was synthesized at 1873 K and rapidly quenched to room temperature. Its structure has been determined using single-crystal X-ray diffraction and compared with results reported using neutron and X-ray powder diffraction from samples prepared by slow cooling. The single-crystal structure from room temperature data was found to belong to the space group P63/m and has the composition Ca2.49Nd7.51(SiO46O1.75 [dicalcium octaneodymium hexakis(orthosilicate dioxide], being isotypic with natural apatite and the previously reported Ca2Nd8(SiO46O2 and Ca2.2Nd7.8(SiO46O1.9. The solubility limit of calcium in the equilibrium state at 1873 K was found to occur at a composition of Ca2+xNd8–x(SiO46O2–0.5x, where x = 0.49.

  10. Relevance of the choice of spark plasma sintering parameters in obtaining a suitable microstructure for iodine-bearing apatite designed for the conditioning of I-129

    Energy Technology Data Exchange (ETDEWEB)

    Campayo, L., E-mail: lionel.campayo@cea.fr [CEA, DEN, DTCD/SECM/LDMC – Marcoule, F-30207 Bagnols-sur-Cèze (France); Le Gallet, S. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-UB, 9 Av. Alain Savary, BP 47870, 21078 Dijon Cedex (France); Perret, D.; Courtois, E. [CEA, DEN, DTCD/SECM/LDMC – Marcoule, F-30207 Bagnols-sur-Cèze (France); Cau Dit Coumes, C. [CEA, DEN, DTCD/SPDE/LP2C – Marcoule, F-30207 Bagnols-sur-Cèze (France); Grin, Yu. [Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden (Germany); Bernard, F. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-UB, 9 Av. Alain Savary, BP 47870, 21078 Dijon Cedex (France)

    2015-02-15

    Highlights: • Modeling of reactive sintering by SPS of an iodoapatite for waste immobilization. • Use of a statistical approach to surmount the complexity of the process. • The supposed most resistant microstructure towards leaching is obtained at 450 °C. • Pressure has no influence in the liquid sintering regime. - Abstract: The high chemical durability of iodine-bearing apatite phases makes them potentially attractive for immobilizing radioactive iodine. Reactive spark plasma sintering provides a dense ceramic as a wasteform. A design-of-experiments (DOE) approach was adopted to identify the main process/material parameters and their first order interactions in order to specify experimental conditions guaranteeing complete reaction, relative density of the wasteform exceeding 92% and the largest possible grain size. For a disposal of the wasteform in a deep geological repository, these characteristics allow minimization of the iodine release by contact with groundwater. It was found that sintering at a temperature of 450 °C with an initial specific surface area of 3.3 m{sup 2} g{sup −1} for the powder reactants is sufficient in itself to achieve the targeted characteristics of the wasteform. However, this relies on a liquid sintering regime the efficiency of which can be limited by the lead iodide initial content in the mix as well as by its particle size.

  11. Stability of Lead Immobilized by Apatite in Lead-Containing Rhizosphere Soil of Buckwheat (Fagopyrum esculentum) and Hairy Vetch (Vicia villosa).

    Science.gov (United States)

    Katoh, Masahiko; Matsuoka, Hideaki; Sato, Takeshi

    2015-01-01

    This study conducted plant growth experiments using a rhizobox system to understand the growth of buckwheat and hairy vetch as well as the stability of lead immobilized by hydroxyapatite (HAP) in the lead-containing rhizosphere soil. The shoot dry weight of buckwheat did not significantly differ between the lead-containing rhizosphere soil with and without HAP, whereas that of hairy vetch with rhizosphere soil without HAP was reduced. Lead was not accumulated from the rhizosphere soil to the shoots of either plant when HAP was added. The percentage of each lead fraction in sequential extraction was approximately the same through the 3 mm of rhizosphere soils from the root surface and non-planted soil, with and without the addition of HAP. For hairy vetch, the amount of water-soluble lead in the HAP-added rhizosphere soil within 3 mm thickness from the root surface did not increase. However, for buckwheat, the amount of water-soluble lead in the HAP-added rhizosphere soil 1 mm from the root surface increased to the same level as that in the non-planted soil without HAP. Our results suggest that when applying phytostabilization combined with apatite to lead-contaminated soil, the plant that cannot re-mobilize lead should be selected. PMID:25747247

  12. The behavior during water-mineral interaction of britholite, an analogue of an apatite structured potential long-term actinide host phase

    International Nuclear Information System (INIS)

    Neodymium britholite (Ca9Nd(PO4)5SiO2F2) dissolution rates have been studied because it is an analogue for potential actinide waste hosts; it is believed that the behavior of Nd is representative of that of the actinide elements. Steady-state dissolution rates of britholite were measured in closed and open system reactors as a function of aqueous solution composition at 25 to 90 deg C. Measured britholite dissolution rates based on Ca, P, and F release are found to be close to corresponding apatite dissolution rates; these rates at 25 deg C decrease from 10-8 to 10-11 mol/m2/s with increasing pH from 4 to 12. Measured Nd release rates are far slower than those of these other elements; Nd concentrations in solution appear to be in equilibrium with NdPO4, which limits aqueous Nd concentrations to less than 10-12 mol/kg at near neutral conditions. By analogy, it appears likely that aqueous actinide release from analogous waste hosts will be similarly limited by the precipitation of sparingly soluble AcPO4 phases. (authors)

  13. Denudation and uplift of the Mawson Escarpment (eastern Lambert Graben, Antarctica) as indicated by apatite fission track data and geomorphological observation

    Science.gov (United States)

    Lisker, F.; Gibson, H.; Wilson, C.J.; Läufer, A.

    2007-01-01

    Analysis of three vertical profiles from the southern Mawson Escarpment (Lambert Graben) reveals apatite fission track (AFT) ages ranging from 102±20 to 287±23 Ma and mean lengths of 12.2 to 13.0 μm. Quantitative thermal histories derived from these data consistently indicate onset of slow cooling below 110°C began sometime prior to 300 Ma, and a second stage of rapid cooling from paleotemperatures up to ≤100°C to surface temperatures occurred in the Late Cretaceous – Paleocene. The first cooling phase refers to Carboniferous – Jurassic basement denudation up to 5 km associated with the initial rifting of the Lambert Graben. The presence of the ancient East Antarctic Erosion Surface and rapid Late Cretaceous – Paleocene cooling indicate a second denudational episode during which up to 4.5 km of sedimentary cover rocks were removed, and that is likely linked to the Cretaceous Gondwana breakup between Antarctica and India and subsequent passive continental margin formation.

  14. Non-cytotoxic organic-inorganic hybrid bioscaffolds: An efficient bedding for rapid growth of bone-like apatite and cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    John, Lukasz, E-mail: lukasz.john@chem.uni.wroc.pl [Faculty of Chemistry, University of Wroclaw, 14 F. Joliot-Curie, 50-383 Wroclaw (Poland); Baltrukiewicz, Marta; Sobota, Piotr [Faculty of Chemistry, University of Wroclaw, 14 F. Joliot-Curie, 50-383 Wroclaw (Poland); Brykner, Renata; Cwynar-Zajac, Lucja [Department of Histology and Embryology, Wroclaw Medical University, 6a Chalubinskiego, 50-368 Wroclaw (Poland); Dziegiel, Piotr [Department of Histology and Embryology, Wroclaw Medical University, 6a Chalubinskiego, 50-368 Wroclaw (Poland); Department of Histology and Embryology, Poznan University of Medical Sciences, 6 Swiecickiego, 61-781 Poznan (Poland)

    2012-10-01

    Synthesis and characterization of organic-inorganic macroporous hybrid scaffolds were investigated. The materials were prepared by combining 2-hydroxyethylmethacrylate (HEMA) and triethoxyvinylsilane (TEVS) chemically modified by Ca{sup 2+} and PO{sub 4}{sup 3-} ions via sol-gel route. In this study we have constructed a sugar-based cracks-free three-dimensional (3D) network with interconnected porous architecture within the range of 150-300 {mu}m and rough topography. The obtained results revealed that both topography and composition of prepared materials allow rapid growth of the bone-like apatite (HAp) layer on their surface after soaking in biological medium. Preliminary studies have shown that hybrids covered by HAp are non-cytotoxic and allow cell proliferation that make them a promising scaffolds in the field of bone regenerative medicine. The materials were mainly characterized by powder X-ray diffraction analysis (PXRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS) and transmission electron microscopy-energy-dispersive spectroscopy (TEM-EDS). Highlights: Black-Right-Pointing-Pointer Sol-gel derived biomaterials. Black-Right-Pointing-Pointer 3D organic-inorganic hybrid composites for bone tissue engineering. Black-Right-Pointing-Pointer Sugar-templated cracks-free macroporous scaffolds. Black-Right-Pointing-Pointer 2-hydroxyethylmethacrylate/triethoxyvinylsilane blend doped with calcium and phosphate ions. Black-Right-Pointing-Pointer Non-cytotoxic bedding for fibroblasts proliferation.

  15. Using the chemical analysis of magnetite to constrain various stages in the formation and genesis of the Kiruna-type chadormalu magnetite-apatite deposit, Bafq district, Central Iran

    Science.gov (United States)

    Heidarian, Hassan; Lentz, David; Alirezaei, Saeed; Peighambari, Sima; Hall, Douglas

    2016-03-01

    Textural and compositional data are presented for different types of magnetite in the Chadormalu iron deposit to discern the genesis of various styles of mineralization. Samples were chosen according to their paragenetic relations to apatite and their host setting: magnetite-apatite veins in the altered host rocks, disseminated magnetite-apatite assemblages in the marginal parts of the main ore body, and massive magnetite associated with irregular apatite veinlets from internal part of the main ore body. Scanning electron microscopy - back scatter electron (SEM-BSE) images reveal that there are three main generations of magnetite in each of the different magnetite-apatite assemblages. Primary magnetite (Mag1) features abundant porosity and a dark appearance. A second generation of magnetite (Mag2) replacing Mag1 shows a lighter appearance with both sharp and gradational contacts with the primary magnetite crystals. The two magnetite types are related to dissolution-precipitation processes due to changing physico-chemical parameters of the ore fluids. A third type of magnetite (Mag3) with a recrystallized appearance and foam-like triple junctions was mostly observed in magnetite-apatite veins in the main ore body and in veins hosted by altered rocks. Electron probe microanalyses (EPMA) were utilized to discriminate the various magnetite generations in the different magnetite-apatite assemblages. Applying published elemental discrimination diagrams shows that most primary magnetites fall into the hydrothermal- and Kiruna-type fields. Primary magnetite contains lower FeO (88.77-93.65 wt.%; average 91.5 wt.%), and higher SiO2 (0.21-2.26 wt.%; ave. 0.32 wt.%), Al2O3 (0.001-0.45 wt.%; ave. 0.053 wt.%), and CaO (0.002-0.48 wt.%; ave. 0.078 wt.%) contents, which might be related to magmatically derived fluids. Secondary magnetites have higher FeO (89.23-93.49 wt.%; ave. 92.11 wt.%), lower SiO2 (0.037-0.189 wt.%; ave. 0.072 wt.%), Al2O3 (0.004-0.072 wt.%; ave. 0.019 wt

  16. The complex post-rift evolution of the South Atlantic margin, South Africa: new insights from joint inversion of apatite (U-Th)/He and fission track thermochronometry.

    Science.gov (United States)

    Wildman, Mark; Brown, Roderick; Persano, Cristina; Beucher, Romain; Stuart, Finlay

    2013-04-01

    The continental edge of southwestern Africa has long been seen as a type example of a high elevation passive margin, with its characteristic topography forming during or shortly after rifting (c. 130 Ma). Recent work along the South Atlantic passive margin has highlighted the importance of interactions between rift-tectonics, mantle flow and dynamic topography on controlling margin evolution, however, the temporal relationship between these processes is still poorly understood. There is now increasing evidence from satellite imagery, onshore field observations (e.g. Viola et al., 2012) and offshore sedimentary basin analysis (e.g. Hirsch et al., 2010) that suggests that these processes have resulted in a much more complex structural and thermal history along the margin than previously thought. A critical step towards developing a better understanding of the post-rift evolution of this margin is to quantify the surface response (i.e. uplift and erosion) to these major structural and thermal events. Apatite fission track analysis (AFTA) has been used world-wide as a powerful means of extracting quantitative constraints on the timing and rate of major episodes of onshore denudation. Previous AFTA studies in SW Africa have identified two distinct cooling events occurred during early and late Cretaceous, respectively. However, in places AFT ages vary significantly over relatively short distances and this has been interpreted to indicate local differential erosion levels controlled by tectonic displacements related to fault reactivation. A limitation of the AFT system is that it is sensitive to a temperature range of c. 120-60°C and therefore is unable to evaluate the magnitude of denudation episodes where the amounts are less than c. 1.5-2 km. So while the Cretaceous history of erosion is well established from existing AFTA data, the details of the timing and amount of erosion occurring during the Cenozoic remain relatively poorly constrained. The apatite (U

  17. Bone-bonding behavior under load-bearing conditions of an alumina ceramic implant incorporating beads coated with glass-ceramic containing apatite and wollastonite.

    Science.gov (United States)

    Li, Z L; Kitsugi, T; Yamamuro, T; Chang, Y S; Senaha, Y; Takagi, H; Nakamura, T; Oka, M

    1995-09-01

    Alumina ceramic with a porous surface coated with glass-ceramic containing apatite and wollastonite (AW-GC) was implanted in a state of press-fit under load-bearing conditions in the femoral condylus of the mongrel dog and compared with a non-glass-ceramic-coated alumina ceramic. A trapezoid alumina ceramic implant (7 x 10 x 5 mm) with a lateral recess (0.9 mm deep) coated with alumina ceramic beads (mean diameter, 750 microns) in a single layer was prepared. The alumina ceramic beads were bonded to the alumina ceramic substratum using an identical alumina binder. The thickness of coating was 10-50 microns (mean, 30 microns). The surface of the beads and the substratum of the alumina implant were coated with AW-GC. A pull-out test and histologic examination were performed at 4, 8, and 24 weeks after implantation. The interfacial shear load was significantly increased from 8 to 24 weeks in both groups. The shear load of the glass-ceramic-coated implant was significantly greater than that of the noncoated implant at every stage. The interface shear load of the noncoated implant was 12.13 +/- 2.76 kg at 4 weeks, 13.92 +/- 4.18 kg at 8 weeks, and 24.17 +/- 5.17 kg at 24 weeks after implantation. The interface shear load of the glass-ceramic-coated implant was 17.96 +/- 2.81 kg at 4 weeks, 24.92 +/- 9.87 kg at 8 weeks, and 34.83 +/- 4.12 kg at 24 weeks after implantation. Histologic examination showed more ingrown bone tissue in the glass-ceramic-coated implants. It is suggested that AW-GC stimulated the bone ingrowth.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8567706

  18. Mesozoic exhumation history and palaeolandscape of the Iberian Massif in eastern Galicia from apatite fission-track and (U+Th)/He data

    Science.gov (United States)

    Grobe, R. W.; Alvarez-Marrón, J.; Glasmacher, U. A.; Stuart, F. M.

    2014-03-01

    Apatite fission-track (AFT) and (U+Th)/He (AHe) data, combined with time-temperature inverse modelling, reveal the cooling and exhumation history of the Iberian Massif in eastern Galicia since the Mesozoic. The continuous cooling at various rates correlates with variation of tectonic boundary conditions in the adjacent continental margins. The data provide constraints on the 107 timescale longevity of a relict paleolandscape. AFT ages range from 68 to 174 Ma with mean track lengths of 10.7 ± 2.6 to 12.6 ± 1.8 μm, and AHe ages range from 73 to 147 Ma. Fastest exhumation (≈0.25 km/Ma) occurred during the Late Jurassic to Early Cretaceous main episode of rifting in the adjacent western and northern margins. Exhumation rates have decreased since then and have been approximately one order of magnitude lower. Across inland Galicia, the AFT data are consistent with Early Cretaceous movement on post-Variscan NE trending faults. This is coeval with an extensional episode offshore. The AHe data in this region indicate less than 1.7 km of denudation in the last 100 Ma. This low exhumation suggests the attainment of a mature landscape during Late Cretaceous post-rift tectonic stability, whose remains are still preserved. The low and steady rate of denudation prevailed across inland Galicia despite minor N-S shortening in the northern margin since ≈45 Ma ago. In north Galicia, rock uplift in response to NW strike-slip faulting since Early Oligocene to Early Miocene has caused insufficient exhumation (<3 km) to remove the Mesozoic cooling signal recorded by the AFT data.

  19. A new technique for the assessment of the 3D spatial distribution of the calcium/phosphorus ratio in bone apatite

    International Nuclear Information System (INIS)

    The value and distribution of calcium/phosphorus (Ca/P) ratio in bone vary between healthy and osteoporotic bone. The purpose of this study was the development of a technique for the assessment of the 3D spatial distribution of Ca/P ratio in bone apatite, which could eventually be implemented through a conventional computed tomography (CT) system. A three-material mass-fraction decomposition CT dual energy analysis was optimized. The technique was validated using ten bone phantoms of different, known Ca/P ratio. Their measured average Ca/P ratio showed a mean/maximum deviation from the expected Ca/P ratio of 0.24/0.35. Additionally, three healthy and three inflammation-mediated osteoporotic (IMO) collagen-free rabbit tibia bone samples were assessed, providing promising preliminary results on real bone tissue. The average Ca/P ratios in all IMO samples (1.64–1.65) were found to be lower than in healthy samples (1.67–1.68). Osteoporotic regions in IMO samples were located using Ca/P ratio colour maps and Ca/P ratio values as low as 1.40 ± 0.26 were found. The low Ca/P ratio volume proportion in IMO samples (12.8%–13.9%) was found to be higher than in healthy (5.8%–8.3%) samples. A region growing technique showed a higher homogeneity of Ca/P ratio in healthy than in IMO bone samples. (paper)

  20. Constraining the age and magnitude of uplift in the northern National Petroleum Reserve in Alaska (NPRA)-apatite fission-track analysis of samples from three wells

    Science.gov (United States)

    Houseknecht, David W.; Bird, Kenneth J.; O'Sullivan, Paul

    2011-01-01

    A broad, post-mid-Cretaceous uplift is defined in the northern National Petroleum Reserve in Alaska (NPRA) by regional truncation of Cretaceous strata, thermal maturity patterns, and amounts of exhumation estimated from sonic logs. Apatite fission-track (AFT) analysis of samples from three wells (South Meade No. 1, Topagoruk No. 1, and Ikpikpuk No. 1) across the eastern flank of the uplift indicates Tertiary cooling followed by Quaternary heating. Results from all three wells indicate that cooling, presumably caused by uplift and erosion, started about 75-65 Ma (latest Cretaceous-earliest Tertiary) and continued through the Tertiary Period. Data from South Meade indicate more rapid cooling after about 35-15 Ma (latest Eocene-middle Miocene) followed by a significant increase in subsurface temperature during the Quaternary, probably the result of increased heat flow. Data from Topagoruk and Ikpikpuk include subtle evidence of accelerated cooling starting in the latest Eocene-middle Miocene and possible evidence of increased temperature during the Quaternary. Subsurface temperature perturbations related to the insulating effect of permafrost may have been responsible for the Quaternary temperature increase at Topagoruk and Ikpikpuk and may have been a contributing factor at South Meade. Multiple lines of geologic evidence suggest that the magnitude of exhumation resulting from uplift and erosion is 5,000-6,500 ft at South Meade, 4,000-5,500 ft at Topagoruk, and 2,500-4,000 ft at Ikpikpuk. The results from these wells help to define the broad geometry of the uplift, which increases in magnitude from less than 1,000 ft at the Colville River delta to perhaps more than 7,000 ft along the northwestern coast of NPRA, between Point Barrow and Peard Bay. Neither the origin nor the offshore extent of the uplift, west and north of the NPRA coast, have been determined.

  1. Post break-up tectonic inversion across the southwestern cape of South Africa: New insights from apatite and zircon fission track thermochronometry

    Science.gov (United States)

    Wildman, Mark; Brown, Roderick; Watkins, Ron; Carter, Andrew; Gleadow, Andrew; Summerfield, Michael

    2015-07-01

    The south-west African margin is regarded as an example of a passive continental margin formed by continental rifting following a phase of lithospheric extension and thinning. Recent attention focused on this margin has included theoretical modelling studies of rift processes, plate kinematic studies of the opening geometry and timing, and empirical studies focused on documenting the crustal structure and offshore sedimentary record. Here, we examine the onshore geomorphic and tectonic response to rifting and breakup, with a specific focus on the SW Cape of South Africa. We present 75 new apatite and 8 new zircon fission track analyses from outcrop samples and onshore borehole profiles along the western margin of South Africa. The data are used to derive robust thermal histories that record two discrete phases of accelerated erosional cooling during the Early Cretaceous (150-130 Ma) and Late Cretaceous (100-80 Ma), respectively. Both periods of enhanced erosion are regional in extent, involved km-scale erosion, and extend well inland of the current escarpment zone, albeit with spatially variable intensity and style. The Late Cretaceous episode is also expressed more locally by tectonic reactivation and inversion of major faults causing km-scale differential displacement and erosion. The new AFT data do not exclude the possibility of modest surface uplift occurring during the Cenozoic, but they restrict the depth of regional Cenozoic erosion on the western margin to less than c. 1 km. The inferred pattern and chronology of erosion onshore is consistent with the key features and sediment accumulation patterns within the offshore Orange and Bredasdorp basins. It is suggested that the Late Cretaceous event was triggered by a combination of regional dynamic uplift augmented along the western margin and in the SW Cape by local tectonic forces arising from dextral displacement of the Falkland Plateau along the Falkland-Agulhas Fracture Zone.

  2. Apatite fission-track evidence for regional exhumation in the subtropical Eocene, block faulting, and localized fluid flow in east-central Alaska

    Science.gov (United States)

    Dusel-Bacon, Cynthia; Bacon, Charles R.; O'Sullivan, Paul B.; Day, Warren C.

    2016-01-01

    The origin and antiquity of the subdued topography of the Yukon–Tanana Upland (YTU), the physiographic province between the Denali and Tintina faults, are unresolved questions in the geologic history of interior Alaska and adjacent Yukon. We present apatite fission-track (AFT) results for 33 samples from the 2300 km2 western Fortymile district in the YTU in Alaska and propose an exhumation model that is consistent with preservation of volcanic rocks in valleys that requires base level stability of several drainages since latest Cretaceous–Paleocene time. AFT thermochronology indicates widespread cooling below ∼110 °C at ∼56–47 Ma (early Eocene) and ∼44–36 Ma (middle Eocene). Samples with ∼33–27, ∼19, and ∼10 Ma AFT ages, obtained near a major northeast-trending fault zone, apparently reflect hydrothermal fluid flow. Uplift and erosion following ∼107 Ma magmatism exposed plutonic rocks to different extents in various crustal blocks by latest Cretaceous time. We interpret the Eocene AFT ages to suggest that higher elevations were eroded during the Paleogene subtropical climate of the subarctic, while base level remained essentially stable. Tertiary basins outboard of the YTU contain sediment that may account for the required >2 km of removed overburden that was not carried to the sea by the ancestral Yukon River system. We consider a climate driven explanation for the Eocene AFT ages to be most consistent with geologic constraints in concert with block faulting related to translation on the Denali and Tintina faults resulting from oblique subduction along the southern margin of Alaska.

  3. The chronology and tectonic style of landscape evolution along the elevated Atlantic continental margin of South Africa resolved by joint apatite fission track and (U-Th-Sm)/He thermochronology

    Science.gov (United States)

    Wildman, Mark; Brown, Roderick; Beucher, Romain; Persano, Cristina; Stuart, Fin; Gallagher, Kerry; Schwanethal, James; Carter, Andrew

    2016-03-01

    Atlantic-type continental margins have long been considered "passive" tectonic settings throughout the entire postrift phase. Recent studies question the long-term stability of these margins and have shown that postrift uplift and reactivation of preexisting structures may be a common feature of a continental margin's evolution. The Namaqualand sector of the western continental margin of South Africa is characterized by a ubiquitously faulted basement but lacks preservation of younger geological strata to constrain postrift tectonic fault activity. Here we present the first systematic study using joint apatite fission track and apatite (U-Th-Sm)/He thermochronology to achieve a better understanding on the chronology and tectonic style of landscape evolution across this region. Apatite fission track ages range from 58.3 ± 2.6 to 132.2 ± 3.6 Ma, with mean track lengths between 10.9 ± 0.19 and 14.35 ± 0.22 µm, and mean (U-Th-Sm)/He sample ages range from 55.8 ± 31.3 to 120.6 ± 31.4 Ma. Joint inverse modeling of these data reveals two distinct episodes of cooling at approximately 150-130 Ma and 110-90 Ma with limited cooling during the Cenozoic. Estimates of denudation based on these thermal histories predict approximately 1-3 km of denudation coinciding with two major tectonic events. The first event, during the Early Cretaceous, was driven by continental rifting and the development and removal of synrift topography. The second event, during the Late Cretaceous, includes localized reactivation of basement structures as well as regional mantle-driven uplift. Relative tectonic stability prevailed during the Cenozoic, and regional denudation over this time is constrained to be less than 1 km.

  4. Determination of volatile concentrations in fluorapatite of Martian shergottite NWA 2975 by combining synchrotron FTIR, Raman spectroscopy, EMPA, and TEM, and inferences on the volatile budget of the apatite host-magma

    Science.gov (United States)

    SłAby, Ewa; Koch-Müller, Monika; FöRster, Hans-Jürgen; Wirth, Richard; Rhede, Dieter; Schreiber, Anja; Schade, Ulrich

    2016-02-01

    We combined the focused ion beam sample preparation technique with polarized synchrotron-based FTIR (Fourier transform infrared) spectroscopy, laser-Raman spectroscopy, electron microprobe analysis (EMPA), and transmission electron microscope (TEM) analysis to identify and quantify structurally bound OH, F, Cl, and CO3 groups in fluorapatite from the Northwest Africa 2975 (NWA 2975) shergottite. In this study, the first FTIR spectra of the OH-stretching region from a Martian apatite are presented that show characteristic OH-bands of a F-rich, hydroxyl-bearing apatite. Depending on the method of apatite-formula calculation and whether charge balance is assumed or not, the FTIR-based quantification of the incorporated OH, expressed as wt% H2O, is in variably good agreement with the H2O concentration calculated from electron microprobe data. EMP analyses yielded between 0.35 and 0.54 wt% H2O, and IR data yielded an average H2O content of 0.31 ± 0.03 wt%, consistent with the lower range determined from EMP analyses. The TEM observations implied that the volatiles budget of fluorapatite is magmatic. The water content and the relative volatile ratios calculated for the NWA 2975 magma are similar to those established for other enriched or intermediate shergottites. It is difficult to define the source of enrichment: either Martian wet mantle or crustal assimilation. Comparing the environment of parental magma generation for NWA 2975 with the terrestrial mantle in terms of water content, it displays a composition intermediate between enriched and depleted MORB.

  5. Tectonic and thermal history of the western Serrania del Interior foreland fold and thrust belt and Guarico Basin, north central Venezuela: Implications of new apatite fission track analysis and seismic interpretation

    Science.gov (United States)

    Perez de Armas, Jaime Gonzalo

    Structural analysis, interpretation of seismic reflection lines, and apatite fission-track analysis in the Western Serrania del Interior fold and thrust belt and in the Guarico basin of north-central Venezuela indicate that the area underwent Mesozoic and Tertiary-to-Recent deformation. Mesozoic deformation, related to the breakup of Pangea, resulted in the formation of the Espino graben in the southernmost portion of the Guarico basin and in the formation of the Proto-Caribbean lithosphere between the diverging North and South American plates. The northern margin of Venezuela became a northward facing passive margin. Minor normal faults formed in the Guarico basin. The most intense deformation took place in the Neogene when the Leeward Antilles volcanic island arc collided obliquely with South America. The inception of the basal foredeep unconformity in the Late Eocene-Early Oligocene marks the formation of a perisutural basin on top of a buried graben system. It is coeval with minor extension and possible reactivation of Cretaceous normal faults in the Guarico basin. It marks the deepening of the foredeep. Cooling ages derived from apatite fission-tracks suggest that the obduction of the fold and thrust belt in the study area occurred in the Late Oligocene through the Middle Miocene. Field data and seismic interpretations suggest also that contractional deformation began during the Neogene, and specifically during the Miocene. The most surprising results of the detrital apatite fission-track study are the ages acquired in the sedimentary rocks of the easternmost part of the study area in the foreland fold and thrust belt. They indicate an Eocene thermal event. This event may be related to the Eocene NW-SE convergence of the North and South American plates that must have caused the Proto-Caribbean lithosphere to be shortened. This event is not related to the collision of the arc with South America, as the arc was far to the west during the Eocene.

  6. Phanerozoic brittle tectonics in the South American Continental Platform, Southeast Brazil: new insights from fission track studies on apatite in reactivated fault zones

    International Nuclear Information System (INIS)

    Apatite Fission Track Method (FTM) studies were performed on samples coming from two different fault domains in the Precambrian basement of southeast Brazil in order to evaluate subsequent Phanerozoic tectonic movements in that part of the South American Platform. The samples studied were collected along brittle faults in the Mantiqueira mountain range and in the Jundiai upland plain (Braganca Paulista and Extrema), approximately 100 km northeast of Sao Paulo, Brazil. The results of paleostress analysis, as well as the presence of as pseudotachylyte material in the reactivated fault zones, indicates a rapid strain rate and high frictional temperature along these faults. The recognition of deformation related to this brittle tectonic regime is of key importance for the reconstruction of Paleozoic and Mesozoic tectonic evolution of the South American Platform. The causal effects of these tectonic readjustments of cratonic rocks during the breakup of West-Gondwana during the Cretaceous and also in younger geological history, are some of the key parameters for understanding the Phanerozoic evolution of the Mantiqueira mountain range. Our FTM data shows the oldest regional thermal histories are recorded in the Jundiai upland plain beginning in the Upper Triassic (∼190 Ma) at 50 deg C, indicating a rapid cooling that is coincident with the tectonic subsidence of the Parana Basin and, probably, the uplift and preservation of Gondwana surface. These data also show slow linear heating (between 50 to 90 deg C) of the southeastern Brazilian margin up to the Lower Cretaceous (∼120 Ma). This phenomenon could either be related to migration of the Trindade plume, or extensional/compressional movements. At ∼120 Ma a structural inversion occurred and the previous slow linear heating was replaced by slow linear cooling (from 90 to 25 deg C) that has persisted up to the present time. Locally, in the younger fault domain, in the Mantiqueira Range near Extrema, fission tracks

  7. Phanerozoic brittle tectonics in the South American Continental Platform, Southeast Brazil: new insights from fission track studies on apatite in reactivated fault zones

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Luiz Felipe Brandini; Hackspacher, Peter Christian [UNESP, Rio Claro, SP (Brazil). Inst. de Geociencias e Ciencias Exatas]. E-mail: lfbrv@yahoo.com.br; Saenz, Carlos Alberto Tello; Iunes, Pedro Jose; Hadler Neto, Julio Cesar [Universidade Estadual de Campinas, SP (Brazil). Instituto de Fisica Gleb Wataghin; Paulo, Sergio R. [Universidade Federal de Mato Grosso, Cuiaba, MT (Brazil). Inst. de Ciencias Exatas e da Terra. Dept. de Fisica

    2005-06-15

    Apatite Fission Track Method (FTM) studies were performed on samples coming from two different fault domains in the Precambrian basement of southeast Brazil in order to evaluate subsequent Phanerozoic tectonic movements in that part of the South American Platform. The samples studied were collected along brittle faults in the Mantiqueira mountain range and in the Jundiai upland plain (Braganca Paulista and Extrema), approximately 100 km northeast of Sao Paulo, Brazil. The results of paleostress analysis, as well as the presence of as pseudotachylyte material in the reactivated fault zones, indicates a rapid strain rate and high frictional temperature along these faults. The recognition of deformation related to this brittle tectonic regime is of key importance for the reconstruction of Paleozoic and Mesozoic tectonic evolution of the South American Platform. The causal effects of these tectonic readjustments of cratonic rocks during the breakup of West-Gondwana during the Cretaceous and also in younger geological history, are some of the key parameters for understanding the Phanerozoic evolution of the Mantiqueira mountain range. Our FTM data shows the oldest regional thermal histories are recorded in the Jundiai upland plain beginning in the Upper Triassic ({approx}190 Ma) at 50 deg C, indicating a rapid cooling that is coincident with the tectonic subsidence of the Parana Basin and, probably, the uplift and preservation of Gondwana surface. These data also show slow linear heating (between 50 to 90 deg C) of the southeastern Brazilian margin up to the Lower Cretaceous ({approx}120 Ma). This phenomenon could either be related to migration of the Trindade plume, or extensional/compressional movements. At {approx}120 Ma a structural inversion occurred and the previous slow linear heating was replaced by slow linear cooling (from 90 to 25 deg C) that has persisted up to the present time. Locally, in the younger fault domain, in the Mantiqueira Range near Extrema

  8. Long-term erosion and exhumation of the “Altiplano Antioqueño”, Northern Andes (Colombia) from apatite (U Th)/He thermochronology

    Science.gov (United States)

    Restrepo-Moreno, Sergio A.; Foster, David A.; Stockli, Daniel F.; Parra-Sánchez, Luis N.

    2009-02-01

    The Antioqueño Plateau (AP) in the northern Cordillera Central, Colombia, is the largest high elevation erosional surface in the Northern Andes. Apatite (U-Th)/He thermochronometry (AHe) of samples collected from two elevation profiles spanning ˜ 2 km of exhumed crustal sections reveal the long-term erosional exhumation of the AP. Sample profiles exhibit AHe ages that increase with elevation from ca. 22 Ma (˜ 760 m) at the bottom of regional scarps to ca. 49 Ma (˜ 2350 m) on top of the AP. A marked inflection point in age versus elevation data at ca. 25 Ma defines the bottom of the exhumed post-Oligocene He partial retention zone (He-PRZ). Elevation-invariant ages below ca. 25 Ma record the onset of rapid exhumation and surface uplift of the AP that led to river incision. A subtle change in slope within the He-PRZ, ca. 41 Ma, is interpreted as a less intense, exhumation-related cooling episode. These two exhumation pulses coincide with the Proto-Andina and Pre-Andina orogenic phases previously proposed for the Colombian Andes, and are synchronous with tectonically driven exhumation events reported for the Peruvian, Bolivian and Argentinean Andes, and for some orogenic systems in the Caribbean. The pulses are correlated with variations in the rates of convergence between Nazca (Farallon) and South America documented for the Middle Eocene and the Late Oligocene suggesting continental-scale controls on uplift and denudation throughout the Andean range. AHe data provide an average erosion rate of ˜ 0.04 mm/yr for the last 25 million years. Erosion rates during the exhumation pulses were in the order of ˜ 0.2-0.4 mm/yr. Similarity between AHe profiles indicates the whole AP was uplifted and exhumed as a coherent structural block, corroborating previous structural evidence for the rigidity and coherence of this crustal block in the Northern Andes. Our results are in agreement with tectonostratigraphic data in the Magdalena and Cauca basins and with proposed

  9. Stable Isotope Analyses of Phosphate Oxygen From Micro-samples of Biological Apatite: A new Routine Procedure for Silverphosphate Micro-precipitation and the Removal of Organic Contamination

    Science.gov (United States)

    Wiedemann-Bidlack, F. B.; Colman, A. S.; Fogel, M. L.

    2003-12-01

    Oxygen isotope analyses in bone and teeth of living and fossil animals are widely used for testing hypotheses about variability of diet and habitat. For the analysis of environmental or dietary changes in the past, tooth enamel has become the preferred study material, because its mineral content is higher than bone and dentine, and the relatively large size of the carbonato-apatite crystals of enamel make it more stable against post mortem diagenetic alteration than dentine or bone. Intra-tooth sampling of dental enamel is increasingly used for the investigation of seasonal climate variability, taking advantage of both the high correlation between an animal's drinking water and the δ 18O in its mineralized tissues and the incremental growth pattern of tooth enamel. The different oxygen-containing ions of bioapatite (phosphate, carbonate, and hydroxyl group) incorporate into the mineral lattice at different rates during enamel mineralization, and differ in their susceptibility against post mortem diagenetic alteration. In addition, it is difficult to account for the different reaction chemistries of phosphate, carbonate, and hydroxyl group using isotope analysis techniques that include all oxygen contained in the enamel (e.g., laser ablation). These problems can be addressed analyzing phosphate oxygen only. However, two major factors limit the potential of δ 18O analyses in dental enamel: A) the starting sample size for isotope analyzes often precludes the use of small teeth or the intra-tooth sampling of a given tooth; B) Small amounts of biogenic organic material in tooth enamel (less than 1% by wt) can reduce the precision and lead to anomalous analytical results in δ 18O measurements on Ag3PO4 produced from tooth enamel. A new procedure was developed for the pre-treatment and δ 18O analysis of phosphate from small samples (500 μ g) of tooth enamel containing organic matter. Ag3PO{4} was precipitated quantitatively for analysis of δ 18Ophosphate using a

  10. Dating Kimberlite Eruption and Erosion Phases Using Perovskite, Zircon, and Apatite (U-Th)/He Geochronology to Link Cratonic Lithosphere Evolution and Surface Processes

    Science.gov (United States)

    Stanley, J. R.; Flowers, R. M.

    2015-12-01

    In many cases it is difficult to evaluate the synchronicity and thus potential connections between disparate geologic events, such as the links between processes in the mantle lithosphere and at the surface. Developing new geochronologic tools and strategies for integrating existing chronologic data with other information is essential for addressing these problems. Here we use (U-Th)/He dating of multiple kimberlitic minerals to date kimberlite eruption and cratonic erosion phases. This approach permits us to more directly assess the link between unroofing and thermomodification of the lithosphere by tying our results to information obtained from mantle-derived clasts in the same pipes. Kimberlites are rich sources of information about the composition of the cratonic lithosphere and its evolution over time. Their xenoliths and xenocrysts can preserve a snapshot of the entire lithosphere and its sedimentary cover at the time of eruption. Accurate geochronology of these eruptions is crucial for interpreting spatiotemporal trends, but kimberlites can be difficult to date using standard techniques. Here we show that the mid-temperature thermochonometers of the zircon and perovskite (U-Th)/He (ZHe, PHe) systems can be viable tools for dating kimberlite eruption. When combined with the low temperature sensitivity of (U-Th)/He in apatite (AHe), the (U-Th)/He system can be used to date both the emplacement and the erosional cooling history of kimberlites. The southern African shield is an ideal location to test the utility of this approach because the region was repeatedly intruded by kimberlites in the Cretaceous, with two major pulses at ~200-110 Ma and ~100-80 Ma. These kimberlites contain a well-studied suite of mantle xenoliths and xenocrysts that document lithospheric heating and metasomatism over this interval. Our ZHe and PHe dates overlap with published eruption ages and add new ages for undated pipes. Our AHe dates constrain the spatial patterns of Cretaceous

  11. A novel apatite, Lu5(SiO4)3N:(Ce,Tb), phosphor material: synthesis, structure and applications for NUV-LEDs.

    Science.gov (United States)

    Guo, Qingfeng; Wang, Qidi; Jiang, Liwei; Liao, Libing; Liu, Haikun; Mei, Lefu

    2016-06-21

    The lutetium containing nitride apatite Lu5(SiO4)3N was prepared by a solid state reaction at high temperature for the first time. Rietveld refinement indicated that the Lu5(SiO4)3N compound has a hexagonal space group of P63/m with cell parameters a = b = 9.700 Å and c = 7.238 Å. Additionally, the results revealed that there are two distinct lutetium sites in the Lu5(SiO4)3N host lattice, i.e. a Lu(1) site with nine coordination (Wyckoff site 4f) and a Lu(2) site with seven coordination (Wyckoff site 6h). Furthermore, the ratio of the number of Lu atoms in Lu(1) and Lu(2) sites is 3 : 2. The band gap for Lu5(SiO4)3N was determined to be 4.12 eV based on the density functional theory (DFT). In the Ce(3+) doped Lu5(SiO4)3N:0.03Ce(3+) compound, the emission peak centered at 462 nm was observed with the Commission International de I'Eclairage (CIE) coordinates of (0.148, 0.184), indicating blue-emission. Remarkably, in Ce(3+) and Tb(3+) co-doped Lu4.97-y(SiO4)3N:0.03Ce(3+),yTb(3+) compounds, the color-tunability was observed with increasing Tb(3+) co-doping rate on moving from blue at Tb(3+) = 0.00 to green at Tb = 0.09, due to the energy transfer from Ce(3+) to Tb(3+) ions being matched well with the decay curve results. Under the excitation at 359 nm, the absolute quantum efficiency (QE) for Lu5(SiO4)3N:0.03Ce(3+) was determined to be 42.13%. This phosphor material could be a platform for modeling a new phosphor and application in the solid-state lighting field. PMID:27165439

  12. Study of retention properties of fluoro-apatite carbonate relative to Ni(II), Am(III) and Th(IV); Etude des proprietes de retention des carbonate fluoroapatites vis-a-vis de Ni(II), Am(III) et Th(IV)

    Energy Technology Data Exchange (ETDEWEB)

    Perrone, Jane [Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France)

    1999-07-12

    Apatite minerals and particularly the carbonated species (francolites), are characterized by their chemical and geological stability and also by their capacity to retain durably a large number of elements. Therefore, they should be able to improve the retention properties of the engineered barriers of a deep geological nuclear waste repository. But there is a wide variety of francolites, so we focused our study on a synthetic carbonate fluoro-apatite of formula: Ca{sub 10}(PO{sub 4}){sub 5}(CO{sub 3})(F,OH){sub 3} and on a natural apatite. We first studied their solubility which is an important criterion for the choice of the materials. A particular attention was also paid to the determination of their surface characteristics and to the study of the radionuclide/solution interactions. Sorption experiments have been performed for the three radionuclides and the influence of various parameters has been investigated. The modelling of the sorption isotherms with surface complexation models leads us to estimate the values of the constants associated to the equilibria under consideration. We have also demonstrated that the phosphate ions of the solution participate to the immobilization of americium as the AmPO{sub 4},xH{sub 2}O compound. Both apatites show high retention levels for the actinides: the sorption is quite total over all the pH range studied and the Kd values are close to 10{sup 4} m{sup 3} kg{sup -1}. Consequently, the use of apatites could be considered as a specific solution for the immobilisation of heavy elements, specially actinides. Moreover, the results indicate that high amounts of carbonates and impurities do not alter the retention properties of francolites. This bears out the feasibility of the use of natural apatites as additives for the engineered barrier materials. (author)

  13. Incorporation of cesium into phosphates of apatitic and rhabdophane lattices. Application to the conditioning of separated radionuclides; Incorporation du cesium dans des phosphates de structure apatitique et rhabdophane. Application au conditionnement des radionucleides separes

    Energy Technology Data Exchange (ETDEWEB)

    Campayo, L

    2003-04-01

    Two phosphate-based materials were investigated for cesium immobilization after its partitioning from spent nuclear fuel: apatites and rhabdophanes. The incorporation of cesium into the apatitic lattice creates steric stresses. These stresses induce the formation of secondary phases which are rapidly leached. The effectiveness of the cesium immobilization in this material is not therefore validated. A second phosphate CsCaNd(PO{sub 4}){sub 2} was consistently found at the end of the leach test and its properties were further characterized. The structure of CsCaNd(PO{sub 4}){sub 2}, which is rhabdophane-like, is made of large channels which enable the incorporation of the largest alkaline cations. The synthesis involves two intermediates: the monazite, NdPO{sub 4}, and a soluble phosphate, CsCaPO{sub 4}. The study of a rhabdophane with 10 wt.% of cesium reveals satisfactory intrinsic properties: a thermal stability up to 1100 C and a leach rate of 10{sup -2} g/(m{sup 2}.d). The next step will be to improve the reaction yield. (author)

  14. Exhumation and erosion rates in southern Africa from apatite fission track and (U-Th)/He analysis: state of research, ongoing work and future perspectives

    Science.gov (United States)

    Wildman, M.; Beucher, R.; Brown, R. W.; Persano, C.; Stuart, F.

    2011-12-01

    .8 and 5 km. Up to now, five of these boreholes have been dated using (U-Th)/He on apatite. This borehole approach allows constraints to be placed on timing and amount of erosion even if the area experienced very little erosion, and critically to also obtain estimates of the palaeothermal gradient We present a first insight of the new U-Th/He ages obtained from these samples together with fission track ages and track length distributions. Modeling using QTQt is also presented and allows the T-t histories enable conclusions about the uplift history of the plateau to be drawn. New surface transects have also been sampled and are currently being processed for Fission-Track and (U-Th)/He analysis. Here we present a detailed summary map of all current available thermochronometry data and new samples available from south-Africa together with the key hypothesis to be tested.

  15. Apatite fission-track thermochronological constraints on the pattern of late Mesozoic-Cenozoic uplift and exhumation of the Qinling Orogen, central China

    Science.gov (United States)

    Chen, Hong; Hu, Jianmin; Wu, Guoli; Shi, Wei; Geng, Yingying; Qu, Hongjie

    2015-12-01

    The Qinling Orogen of central China was formed by intracontinental collision between the North and South China Blocks. The orogen comprises several micro-blocks bounded by sutures and faults, and has undergone long-term intracontinental deformation since the Late Triassic. The micro-blocks include the southern margin of the North China Block (S-NCB), the Northern Qinling Belt (NQB), the Southern Qinling Belt (SQB), and the northern margin of the South China Block (N-SCB). Under a uniform tectonic setting in late Mesozoic-Cenozoic, these micro-blocks have been subjected to a range of deformation styles, as demonstrated by their structural deformation, history of magmatism, and the development of sedimentary basins. To investigate the differences among the micro-blocks and to quantify their uplift and exhumation, we obtained 45 rock samples from eight Mesozoic granites in these micro-blocks, and conducted apatite fission-track (AFT) thermochronological modeling. The results reveal that the Qinling Orogen underwent four distinct stages of rapid cooling histories during the late Mesozoic-Cenozoic, and showed variation in uplift and exhumation whereby the intracontinental deformation started in the south (the N-SCB) and propagated to the north (S-NCB). In the first stage, during the Late Jurassic-Early Cretaceous (ca. 160-120 Ma), rock cooling occurred mainly in the N-SCB, attributed to the clockwise rotation and northward subduction of the South China Block beneath the Qinling Orogen. In the second stage, compression- and extension-related uplift was initiated during the late Early Cretaceous-early Late Cretaceous (ca. 120-90 Ma) in the SQB, consistent with the southward subduction of the North China Block and broadly extensional deformation in the eastern China continent. In the third stage, a gentle regional-scale cooling event that occurred during the latest Cretaceous-Paleocene (ca. 90-50 Ma) started in the NQB and became widespread in the Qinling Orogen. This

  16. Study on controlling the distribution of bioactive apatite polycrystalline nucleuses on titanium surface%控制钛表面生物活性磷灰石多晶核分布的研究

    Institute of Scientific and Technical Information of China (English)

    韦春利; 陈晓明

    2011-01-01

    为了加速钛种植体与骨组织直接实现骨整合的速度,采用表面物理和化学方法处理钛基片,通过控制其在模拟体液中的表面矿化过程,获得适当密度的磷灰石多晶核.用SEM观察磷灰石多晶核的表面形貌和大小,对晶粒平均粒径和间距进行统计;用精密酸度计检测模拟体液的pH值;同时,讨论磷灰石多晶核的形成条件和过程.结果表明,通过控制钛表面粗糙度、氮氧化钠溶液浓度、浸泡的时间,可以在钛表面制备一定密度分布的磷灰石多晶核,且多晶核间距小于骨细胞线度(10-30μm).%In order to accelerate the osseointegration speed between titanium implant and bone tissue, titanium substrates were treated by physical and chemical methods. The treated titanium substrates were immersed in a simulated body fluid (SBF) and proper density apatite polycrysta lline nucleuses were formed by controlling mineralization process. The apatite polycrystalline nucleuses were observed by scanning electron microscope (SEM)to investigate surface morphology and size. Average grain size and space between grains were statistical. The pH value of simulated body fluid (SBF) was measured by precise acidimeter. Also formation condition and process were discussed. The results have verified certain distribution of apatite polycrystalline nucleuses, between which space between of grains is less than osteocytes dimension (10-30μm),were prepared on titanium surface by controlling titanium surface roughness and sodium hydroxide concentration and immersion time.

  17. Evolution of the South Atlantic passive continental margin and lithosphere dynamic movement in Southern Brazil derived from zircon and apatite (U-Th-Sm)/He and fission-track data

    Science.gov (United States)

    Krob, Florian; Stippich, Christian; Glasmacher, Ulrich A.; Hackspacher, Peter C.

    2016-04-01

    Passive continental margins are important geoarchives related to mantle dynamics, the breakup of continents, lithospheric dynamics, and other processes. The main concern yields the quantifying long-term lithospheric evolution of the continental margin between São Paulo and Laguna in southeastern Brazil since the Neoproterozoic. We put special emphasis on the reactivation of old fracture zones running into the continent and their constrains on the landscape evolution. In this contribution, we represent already consisting thermochronological data attained by fission-track and (U-Th-Sm)/He analysis on apatites and zircons. The zircon fission-track ages range between 108.4 (15.0) and 539.9 (68.4) Ma, the zircon (U-Th-Sm)/He ages between 72.9 (5.8) and 427.6 (1.8) Ma whereas the apatite fission-track ages range between 40.0 (5.3) and 134.7 (8.0) Ma, and the apatite (U-Th-Sm)/He ages between 32.1 (1.52) and 92.0 (1.86) Ma. These thermochronological ages from metamorphic, sedimentary and intrusive rocks show six distinct blocks (Laguna, Florianópolis, Curitiba, Ilha Comprida, Peruibe and Santos) with different evolution cut by old fracture zones. Furthermore, models of time-temperature evolution illustrate the differences in Pre- to post-rift exhumation histories of these blocks. The presented data will provide an insight into the complex exhumation history of the continental margin based on the existing literature data on the evolution of the Paraná basin in Brazil and the latest thermochronological data. We used the geological model of the Paraná basin supersequences (Rio Ivaí, Paraná, Gondwana I-III and Bauru) to remodel the subsidence and exhumation history of our consisting thermochronological sample data. First indications include a fast exhumation during the early Paleozoic, a slow shallow (northern blocks) to fast and deep (Laguna block) subduction from middle Paleozoic to Mesozoic time and a extremely fast exhumation during the opening of the South Atlantic

  18. Two high terbium content apatites: Tb{sub 5}Si{sub 2}BO{sub 13} and Tb{sub 4.66}Si{sub 3}O{sub 13}

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Pengyun [Beijing Center for Crystal Research and Development, Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Li, R.K., E-mail: rkli@mail.ipc.ac.cn [Beijing Center for Crystal Research and Development, Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2015-02-15

    Graphical abstract: Two terbium apatites Tb{sub 5}Si{sub 2}BO{sub 13} and Tb{sub 4.66}Si{sub 3}O{sub 13} may be promising magneto-optical materials due to their high terbium content. - Highlights: • Two terbium apatite Tb{sub 5}Si{sub 2}BO{sub 13} and Tb{sub 4.66}Si{sub 3}O{sub 13} crystals were grown by flux method. • Structures of both compounds were determined via single-crystal diffraction. • Both compounds show paramagnetic behaviours down to 2 K. • Both compounds may be promising magneto-optical materials due to high Tb{sup 3+} contents. - Abstract: Two high content terbium apatites, Tb{sub 5}Si{sub 2}BO{sub 13} and Tb{sub 4.66}Si{sub 3}O{sub 13}, have been successfully synthesized by sol-gel method and have been crystallized from high temperature flux. Their structures were identified by single crystal X-ray diffraction and were found to belong to the hexagonal system with space group P6{sub 3}/m and unit cell parameters of a = 9.2569(10) Å, c = 6.8297(12) Å and Z = 2 for Tb{sub 5}Si{sub 2}BO{sub 13} and a = 9.493(4) Å, c = 6.852(5) Å and Z = 2 for Tb{sub 4.66}Si{sub 3}O{sub 13}, respectively. The diffuse optical reflection spectra clearly indicate that the two crystals have good optical transparency in the range of 500-1500 nm. The paramagnetic behaviours of Tb{sub 5}Si{sub 2}BO{sub 13} and Tb{sub 4.66}Si{sub 3}O{sub 13} from 2 K to 300 K are confirmed by magnetic susceptibility measurements. In comparison with other known Tb containing magneto-optical (MO) glass and crystals, Tb{sub 5}Si{sub 2}BO{sub 13} and Tb{sub 4.66}Si{sub 3}O{sub 13} are found to be promising magneto-optical materials in the visible-near IR range due to the high Tb{sup 3+} concentrations in both compounds.

  19. Flotabilidade da apatita e minerais de ganga provenientes de minério sílico-carbonatado com oleato de sódio Floatability of apatite and gangue minerals from silicate-carbonate ores with sodium oleate

    Directory of Open Access Journals (Sweden)

    Michelly dos Santos Oliveira

    2010-09-01

    Full Text Available O beneficiamento dos minérios fosfáticos com ganga silicatada e carbonatada é estritamente necessário para aumentar a produção de concentrados fosfáticos e para suprir a demanda nacional de fertilizantes. Visando a processar esses minérios, esse trabalho estudou, através de testes de microflotação e medidas de potencial zeta, o efeito do oleato de sódio, do amido de milho e da carboximetilcelulose (CMC na superfície dos minerais puros originários do minério sílico-carbonatado de Catalão/GO. Os resultados obtidos mostraram a possibilidade de separação seletiva da apatita, por flotação direta em pH igual a 9, usando-se oleato de sódio como coletor, na ausência de depressores, o que seria inviável industrialmente. Tanto a CMC como o amido deprimem a dolomita, mas não são seletivos, pois deprimem, também, a apatita. O amido apresenta ação depressora sobre a apatita mais forte que a CMC.The processing of phosphate ores containing silicates and carbonates in the gangue is strictly necessary to increase phosphate rock production to meet the Brazilian demand for fertilizers. Aiming at the processing of these ores, this investigation addressed, via microfl otation and zeta potential determinations, the effect of sodium oleate, corn starch and carboxymethylcellulose (CMC on the surfaces of pure minerals from the Catalão/GO silicate-carbonate deposit. The results suggested the possibility of selective apatite concentration via direct fl otation at pH = 9, using sodium oleate as collector, in the absence of depressants; a route that would be industrially unfeasible. Both, CMC and starch, act as dolomite depressants, but the action is not selective, for apatite is also depressed by these reagents. Starch is a stronger apatite depressant than CMC.

  20. Thermal modeling and geomorphology of the south border of the Sao Francisco Craton: thermochronology by fission tracks in apatites;Modelagem termica e geomorfologia da borda sul do Craton do Sao Francisco: termocronologia por tracos de fissao em apatita

    Energy Technology Data Exchange (ETDEWEB)

    Hackspacher, Peter Christian [UNESP, Rio Claro, SP (Brazil). Inst. de Geociencias e Ciencias Exatas; Godoy, Daniel Francoso de; Franco, Ana Olivia Barufi [UNESP, Rio Claro, SP (Brazil). Pos-Graduacao em Geologia Regional; Ribeiro, Luiz Felipe Brandini [NUCLEARGEO, Rio Claro, SP (Brazil); Hadler Neto, Julio Cesar [Universidade Estadual de Campinas (IFGW/UNICAMP), SP (Brazil). Inst. de Fisica Gleb Wataghin

    2007-12-15

    Recent developments in Fission Track thermochronology associated to mesozoic-cenozoic erosion and tectonic presented trough thematic maps (isotemperature), permit to model the landscape evolution in the southern border of the Sao Francisco craton, southeastern Brazil. Paleotemperature, obtained by fission track analysis in apatite, is closely related to geomorphologic interpretations. The area suffered a complex imprint of endogenous and exogenous processes resulting diversified and differentiated relieves. The landscape is strongly controlled by exhumation between Jurassic and Lower Cretaceous, uplift with tectonic denudation related to crustal heating at the Upper Cretaceous and reactivation of faults until the Miocene. This scenario is a result of reactivations of different brittle structures that accommodate the deformation in the southern border of the Sao Francisco craton. The landscape reflects denudations of up to 3 km with preserved remains of erosive surfaces in the topographical tops and chronocorrelates deposits in the basins of the region. (author)

  1. Analysis of the CCRMP Oka-2 rare-earth reference mineral of the britholite-apatite series by electrothermal atomic-absorption and inductively-coupled plasma atomic-emission spectrometry

    International Nuclear Information System (INIS)

    The lanthanides and yttrium in the Canadian Certified Reference Materials Project (CCRMP) new rare-earth mineral reference material, Oka-2, were determined by electrothermal atomic-absorption and inductively-coupled plasma atomic-emission spectrometry (ICPAES) after sample decomposition with acids and separation of the rare-earth metals from phosphate and other matrix elements by precipitation as fluorides and oxalates. Thorium, yttrium and the common major and minor elements were determined by ICPAES after sample decomposition by fusion with lithium meta- and tetraborates and dissolution of the melt in a mixture of dilute nitric acid and ethylenediaminetetra-acetic acid solution. For comparison purposes, silicon, phosphorus, calcium, magnesium and iron were also determined by other methods. The results obtained are compared with other CCRMP values and with those obtained previously for a similar rare-earth mineral from the same geographical area. Oka-2 is considered to be a thorian intermediate member of the britholite-apatite series. (author)

  2. Dynamic of an intra-continental orogenic prism: thermo-chronologic (apatite fission tracks) and tectonic evolution of the axial zone and the piedmont of the west-central Pyrenees

    International Nuclear Information System (INIS)

    This work illustrates the application of thermo chronology to the study of the following geologic issue: the tectonic evolution of the Pyrenean oncologic prism. Thermo-chronology gives information on the vertical movements at the scale of geological eras. Thermo-chronology is based on the following principle: the decay of a nucleus gives birth to a daughter nucleus. Above a specific temperature named closure temperature, the daughter element can diffuse outside the system while below the closure temperature, diffusion is not possible. Consequently thermo-chronology can be considered to date the moment when a mineral goes below a a specific closure temperature. Minerals have different closure temperatures and so by using a suite of thermo-chronometers on a single sample, its cooling path through the crust can be reconstructed. This work focuses on apatite fission track (AFT)analysis which is a low temperature thermo-chronometer. In apatites the temperature range between 60 and 120 Celsius degrees corresponds to the partial annealing zone. The spontaneous fission of one U238 nucleus entails the formation of one fission track. The determination of the initial quantity of U238 is based on the natural steady ratio U238/U235 which equals 137.88. The initial quantity of U235 is determined through the neutron irradiation of the sample. The knowledge of the initial quantity of U238 and the number of tracks in the sample allows the dating of the sample. In this work we combine AFT thermo- chronology with a detailed structural analysis to describe vertical movements related to the thrusting system evolution, and to determine the influence of the latter on the sedimentation/burial/exhumation cycle of the syn-orogenic deposits of the southern fore-land basin

  3. Meso-Cenozoic Uplifting of South Taihang Mountains:Constraints from Apatite Fission Track Data%南太行山中新生代隆升过程:磷灰石裂变径迹证据

    Institute of Scientific and Technical Information of China (English)

    李庶波; 王岳军; 张玉芝; 张立敏; 梁浩; 邱惟

    2015-01-01

    南太行山地区地处华北陆块中部,是研究华北岩石圈减薄、克拉通活化期间山脉隆升与剥露机制的理想场所。本文对太行山南麓的中生代岩浆岩和元古宙变质岩开展了磷灰石裂变径迹低温热年代学研究,获得了相关样品的磷灰石径迹年龄和径迹长度。研究表明,南太行山地区磷灰石裂变径迹表观年龄集中在75~32 Ma 之间,峰值径迹长度在11μm以上,为宽带单峰分布。综合考虑裂变径迹反演,南太行山地区初始隆升始于100 Ma 前,晚白垩世以来的剥蚀去顶量在3 km 以上。100~50 Ma 的构造抬升相对平静,50~40 Ma 及10 Ma 左右以来隆升速度加快,是太行山地区的主要隆升期。南太行山区域上表现为北早南晚的倾伏式差异隆升格局,其新生代隆升与华北东部同期的快速沉降相耦合。以上资料有利于更好认知华北陆块中–新生代冷却史及岩石圈减薄地表响应。%The South Taihang Mountains, tectonically located in the center of the North China Craton, was a stable tectonic zone during Paleoproterozoic and Early Mesozoic, but significantly reactivated since Late Triassic. It is an ideal area for better understanding of the mountain uplifting and unroofing during the Mesozoic lithospheric thinning of the North China Craton. This paper presents the results of our field investigations, apatite fission track dating, track length analysis and tectonothermal modeling of the Paleoproterozoic gneisses and Cretaceous diorite samples. The apatite fission track apparent ages of our samples range from 32 Ma to 75 Ma, significant younger than their corresponding ages of formation. The lengths of the fission tracks for each sample show a broad and unimodal pattern with the peak value of 11 μm. In combination with thermal simulation results and other geological observations, it is inferred that at least 3 km thick superficial materials of the South Taihang Mountains have been unroofed

  4. Did the Kiruna iron ores form as a result of a metasomatic or igneous process? New U-Pb and Nd data for the iron oxide apatite ores and their host rocks in the Norrbotten region of northern Sweden

    Science.gov (United States)

    Westhues, A.; Hanchar, J. M.; Whitehouse, M. J.; Fisher, C. M.

    2012-12-01

    A number of iron deposits near Kiruna in the Norrbotten region of northern Sweden are of the iron oxide apatite (IOA) type of deposits; also referred to as Kiruna-type deposits. They are commonly considered a subgroup or end-member of iron oxide copper gold (IOCG) deposits, containing no economic grades of copper or gold. Both IOCG and IOA deposits are characterized by abundant low-Ti Fe oxides, an enrichment in REE, and intense sodium and potassium wall-rock alteration adjacent to the ores. Deposits of these types are of a great economic importance, not only for iron, but also for other elements such as rare earth elements (REE) or uranium. Kiruna, the type locality of the IOA type of mineral deposits, is the focus of this study. Despite a century-long mining history and 2500 Mt of iron ore produced in the region to date (with grades of 30 to 70 wt.% Fe), the genesis of these deposits is poorly understood: theories of a magmatic vs. a hydrothermal or metasomatic origin have been debated, and the timing of mineralization of the ores in the Norbotten region has never been directly dated. The results anticipated from this study will provide a better understanding of the nature of the IOA type of mineral deposits and their relation to IOCG deposits such as Olympic Dam in Australia. An array of geochemical methods is used in order to gain insights on the emplacement history of the host rocks, their subsequent alteration, and the ore genesis of these deposits. This includes in situ U/Pb geochronology of zircon, monazite, and titanite to con