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

International Nuclear Information System (INIS)

Piccirillo, C.; Silva, M.F.; Pullar, R.C.; Braga da Cruz, I.; Jorge, R.; Pintado, M.M.E.; Castro, P.M.L.

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 °C, giving a biphasic material of hydroxyapatite and tricalcium phosphate (Ca 10 (PO 4 ) 6 (OH) 2 and β-Ca(PO 4 ) 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 10 (PO 4 ) 6 Cl 2 ) and fluorapatite (Ca 10 (PO 4 ) 6 F 2 ) were obtained using CaCl 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: ► 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

Adsorption and release of amino acids mixture onto apatitic calcium phosphates analogous to bone mineral

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El Rhilassi, A.; Mourabet, M.; El Boujaady, H.; Bennani-Ziatni, M.; Hamri, R. El; Taitai, A.

2012-10-01

Study focused on the interaction of adsorbate with poorly crystalline apatitic calcium phosphates analogous to bone mineral. Calcium phosphates prepared in water-ethanol medium at physiological temperature (37 °C) and neutral pH, their Ca/P ratio was between 1.33 and 1.67. Adsorbate used in this paper takes the mixture form of two essential amino acids L-lysine and DL-leucine which have respectively a character hydrophilic and hydrophobic. Adsorption and release are investigated experimentally; they are dependent on the phosphate type and on the nature of adsorbate L-lysine, DL-leucine and their mixture. Adsorption of mixture of amino acids on the apatitic calcium phosphates is influenced by the competition between the two amino acids: L-lysine and DL-leucine which exist in the medium reaction. The adsorption kinetics is very fast while the release kinetics is slow. The chemical composition of apatite has an influence on both adsorption and release. The interactions adsorbate-adsorbent are electrostatic type. Adsorption and release reactions of the amino acid mixture are explained by the existence of the hydrated surface layer of calcium phosphate apatite. The charged sbnd COOsbnd and sbnd NH3+ of adsorbates are the strongest groups that interact with the surface of apatites, the adsorption is mainly due to the electrostatic interaction between the groups sbnd COOsbnd of amino acids and calcium Ca2+ ions of the apatite. Comparative study of interactions between adsorbates (L-lysine, DL-leucine and their mixture) and apatitic calcium phosphates is carried out in vitro by using UV-vis and infrared spectroscopy IR techniques.

Effect of strontium addition and chitosan concentration variation on cytotoxicity of chitosan-alginate-carbonate apatite based bone scaffold

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Perkasa, Rilis Eka; Umniati, B. Sri; Sunendar, Bambang

2017-09-01

Bone scaffold is one of the most important component in bone tissue engineering. Basically, bone scaffold is a biocompatible structure designed to replace broken bone tissue temporarily. Unlike conventional bone replacements, an advanced bone scaffold should be bioactive (e.g: supporting bone growth) and biodegradable as new bone tissue grow, while retain its mechanical properties similarity with bone. It is also possible to add more bioactive substrates to bone scaffold to further support its performance. One of the substrate is strontium, an element that could improve the ability of the bone to repair itself. However, it must be noted that excessive consumption of strontium could lead to toxicity and diseases, such as osteomalacia and hypocalcemia. This research aimed to investigate the effect of strontium addition to the cytotoxic property of chitosan-alginate-carbonate apatite bone scaffold. The amount of strontium added to the bone scaffold was 5% molar of the carbonate apatite content. As a control, bone scaffold without stronsium (0% molar) were also made. The effect of chitosan concentration variation on the cytotoxicity were also observed, where the concentration varies on 1% and 3% w/v of chitosan solution. The results showed an optimum result on bone scaffold sample with 5% molar of strontium and 3% chitosan, where 87.67% cells in the performed MTS-Assay cytotoxicity testing survived. This showed that the use of up to 5% molar addition of strontium and 3% chitosan could enhance the survivability of the cell.

Protein-free formation of bone-like apatite: New insights into the key role of carbonation.

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Deymier, Alix C; Nair, Arun K; Depalle, Baptiste; Qin, Zhao; Arcot, Kashyap; Drouet, Christophe; Yoder, Claude H; Buehler, Markus J; Thomopoulos, Stavros; Genin, Guy M; Pasteris, Jill D

2017-05-01

The nanometer-sized plate-like morphology of bone mineral is necessary for proper bone mechanics and physiology. However, mechanisms regulating the morphology of these mineral nanocrystals remain unclear. The dominant hypothesis attributes the size and shape regulation to organic-mineral interactions. Here, we present data supporting the hypothesis that physicochemical effects of carbonate integration within the apatite lattice control the morphology, size, and mechanics of bioapatite mineral crystals. Carbonated apatites synthesized in the absence of organic molecules presented plate-like morphologies and nanoscale crystallite dimensions. Experimentally-determined crystallite size, lattice spacing, solubility and atomic order were modified by carbonate concentration. Molecular dynamics (MD) simulations and density functional theory (DFT) calculations predicted changes in surface energy and elastic moduli with carbonate concentration. Combining these results with a scaling law predicted the experimentally observed scaling of size and energetics with carbonate concentration. The experiments and models describe a clear mechanism by which crystal dimensions are controlled by carbonate substitution. Furthermore, the results demonstrate that carbonate substitution is sufficient to drive the formation of bone-like crystallites. This new understanding points to pathways for biomimetic synthesis of novel, nanostructured biomaterials. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

Strontium ranelate changes the composition and crystal structure of the biological bone-like apatite produced in osteoblast cell cultures.

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Querido, William; Campos, Andrea P C; Martins Ferreira, Erlon H; San Gil, Rosane A S; Rossi, Alexandre M; Farina, Marcos

2014-09-01

We evaluate the effects of strontium ranelate on the composition and crystal structure of the biological bone-like apatite produced in osteoblast cell cultures, a system that gave us the advantage of obtaining mineral samples produced exclusively during treatment. Cells were treated with strontium ranelate at concentrations of 0.05 and 0.5 mM Sr(2+). Mineral substances were isolated and analyzed by using a combination of methods: Fourier transform infrared spectroscopy, solid-state (1)H nuclear magnetic resonance, X-ray diffraction, micro-Raman spectroscopy and energy dispersive X-ray spectroscopy. The minerals produced in all cell cultures were typical bone-like apatites. No changes occurred in the local structural order or crystal size of the minerals. However, we noticed several relevant changes in the mineral produced under 0.5 mM Sr(2+): (1) increase in type-B CO3 (2-) substitutions, which often lead to the creation of vacancies in Ca(2+) and OH(-) sites; (2) incorporation of Sr(2+) by substituting slightly less than 10 % of Ca(2+) in the apatite crystal lattice, resulting in an increase in both lattice parameters a and c; (3) change in the PO4 (3-) environments, possibly because of the expansion of the lattice; (4) the Ca/P ratio of this mineral was reduced, but its (Ca+Sr)/P ratio was the same as that of the control, indicating that its overall cation/P ratio was preserved. Thus, strontium ranelate changes the composition and crystal structure of the biological bone-like apatite produced in osteoblast cell cultures.

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.

Apatite glass-ceramics: a review

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Duminis, Tomas; Shahid, Saroash; Hill, Robert Graham

2016-12-01

This article is a review of the published literature on apatite glass-ceramics (GCs). Topics covered include crystallization mechanisms of the various families of the apatite GCs and an update on research and development on apatite GCs for applications in orthopedics, dentistry, optoelectronics and nuclear waste management. Most apatite GCs crystallize through a homogenous nucleation and crystallization mechanism, which is aided by a prior liquid-liquid phase separation. Careful control of the base glass composition and heat-treatment conditions, which determine the nature and morphology of the crystal phases in the GC can produce GC materials with exceptional thermal, mechanical, optical and biological properties. The GCs reviewed for orthopedic applications exhibit suitable mechanical properties and can chemically bond to bone and stimulate its regeneration. The most commercially successful apatite GCs are those developed for dental veneering. These materials exhibit excellent translucency and clinical esthetics, and mimic the natural tooth mineral. Due to the ease of solid solution of the apatite lattice, rare earth doped apatite GCs are discussed for potential applications in optoelectronics and nuclear waste management. One of the drawbacks of the commercial apatite GCs used in orthopedics is the lack of resorbability, therefore the review provides a direction for future research in the field.

Preparation of mica/apatite glass-ceramics biomaterials

International Nuclear Information System (INIS)

Liu Yong; Sheng Xiaoxian; Dan Xiaohong; Xiang Qijun

2006-01-01

Glass-ceramics have become more and more important biomaterials. In this work mica glass/apatite composites with various compositions were prepared by casting and subsequent heat treatments. The effects of composition, phase constitution and crystallinity on mechanical properties, including elastic modulus and transverse rupture strength (TRS), were investigated by using X-ray diffraction analyses (XRD), scanning electron microscopy (SEM) and mechanical tests. Results show that addition of apatite composition in mica glass accelerates the crystallization process and induces the formation of fluoroapatite phase, and the nucleation of apatite crystals occurs before that of mica crystals. The fuoroapatite in this work is needle-like, which is almost the same to that in human bone. The transverse rupture strength increases with the content of fluoroapatite and the crystallinity increasing, except that at a low apatite content the mechanical properties are lower than those of mica glass under the same processing conditions. The transverse rupture strength and elastic modulus obtained in this work fall in the range of those of human bone. SBF immersion test demonstrates good bioactivity of this biomaterial

Carbonate substitution in the mineral component of bone: Discriminating the structural changes, simultaneously imposed by carbonate in A and B sites of apatite

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Madupalli, Honey; Pavan, Barbara; Tecklenburg, Mary M. J.

2017-11-01

The mineral component of bone and other biological calcifications is primarily a carbonate substituted calcium apatite. Integration of carbonate into two sites, substitution for phosphate (B-type carbonate) and substitution for hydroxide (A-type carbonate), influences the crystal properties which relate to the functional properties of bone. In the present work, a series of AB-type carbonated apatites (AB-CAp) having varying A-type and B-type carbonate weight fractions were prepared and analyzed by Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), and carbonate analysis. A detailed characterization of A-site and B-site carbonate assignment in the FTIR ν3 region is proposed. The mass fractions of carbonate in A-site and B-site of AB-CAp correlate differently with crystal axis length and crystallite domain size. In this series of samples reduction in crystal domain size correlates only with A-type carbonate which indicates that carbonate in the A-site is more disruptive to the apatite structure than carbonate in the B-site. High temperature methods were required to produce significant A-type carbonation of apatite, indicating a higher energy barrier for the formation of A-type carbonate than for B-type carbonate. This is consistent with the dominance of B-type carbonate substitution in low temperature synthetic and biological apatites.

The Orientation of Nanoscale Apatite Platelets in Relation to Osteoblastic-Osteocyte Lacunae on Trabecular Bone Surface.

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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.

Preparation of a non-woven poly(ε-caprolactone) fabric with partially embedded apatite surface for bone tissue engineering applications by partial surface melting of poly(ε-caprolactone) fibers.

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Kim, In Ae; Rhee, Sang-Hoon

2017-07-01

This article describes a novel method for the preparation of a biodegradable non-woven poly(ε-caprolactone) fabric with a partially embedded apatite surface designed for application as a scaffold material for bone tissue engineering. The non-woven poly(ε-caprolactone) fabric was generated by the electro-spinning technique and then apatite was coated in simulated body fluid after coating the PVA solution containing CaCl 2 ·2H 2 O. The apatite crystals were partially embedded or fully embedded into the thermoplastic poly(ε-caprolactone) fibers by controlling the degree of poly(ε-caprolactone) fiber surface melting in a convection oven. Identical apatite-coated poly(ε-caprolactone) fabric that did not undergo heat-treatment was used as a control. The features of the embedded apatite crystals were evaluated by FE-SEM, AFM, EDS, and XRD. The adhesion strengths of the coated apatite layers and the tensile strengths of the apatite coated fabrics with and without heat-treatment were assessed by the tape-test and a universal testing machine, respectively. The degree of water absorbance was assessed by adding a DMEM droplet onto the fabrics. Moreover, cell penetrability was assessed by seeding preosteoblastic MC3T3-E1 cells onto the fabrics and observing the degrees of cell penetration after 1 and 4 weeks by staining nuclei with DAPI. The non-woven poly(ε-caprolactone) fabric with a partially embedded apatite surface showed good water absorbance, cell penetrability, higher apatite adhesion strength, and higher tensile strength compared with the control fabric. These results show that the non-woven poly(ε-caprolactone) fabric with a partially embedded apatite surface is a potential candidate scaffold for bone tissue engineering due to its strong apatite adhesion strength and excellent cell penetrability. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1973-1983, 2017. © 2017 Wiley Periodicals, Inc.

Can Polyphosphate Biochemistry Affect Biological Apatite Saturation?

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Omelon, S. J.; Matsuura, N.; Gorelikov, I.; Wynnyckyj, C.; Grynpas, M. D.

2010-12-01

Phosphorus (P) is an important and limiting element for life. One strategy for storing ortho phosphates (Pi) is polymerization. Polymerized Pi's (polyphosphates: (PO3-)n: polyPs) serve as a Pi bank, as well as a catiion chelator, energy source, & regulator of responses to stresses in the stationary phase of culture growth and development1. PolyP biochemistry has been investigated in yeasts, bacteria & plants2. Bigeochemical cycling of P includes the condensation of Pi into pyro (P2O7-4), & polyPs, & the release of Pi from these compounds by the hydrolytic degradation of Pi from phosphomonoester bonds. Alkaline phosphatase (ALP) is one of the predominate enzymes for regenerating Pi in aquatic systems3, & it cleaves Pi from polyPs. ALP is also the enzyme associated with apatite biomineralization in vertebrates4. PolyP was proposed to be the ALP substrate in bone mineralization5. Where calcium ions are plentiful in many aquatic environments, there is no requirement for aquatic life to generate Ca-stores. However, terrestrial vertebrates benefit from a bioavailable Ca-store such as apatite. The Pi storage strategy of polymerizing PO4-3 into polyPs dovetails well with Ca-banking, as polyPs sequester Ca, forming a neutral calcium polyphosphate (Ca-polyP: (Ca(PO3)2)n) complex. This neutral complex represents a high total [Ca+2] & [PO4-3], without the threat of inadvertent apatite precipitation, as the free [Ca+2] & [PO4-3], and therefore apatite saturation, are zero. Recent identification of polyP in regions of bone resorption & calcifying cartilage5 suggests that vertebrates may use polyP chemistry to bank Ca+2 and PO4-3. In vitro experiments with nanoparticulate Ca-polyP & ALP were undertaken to determine if carbonated apatite could precipitate from 1M Ca-polyP in Pi-free “physiological fluid” (0.1 M NaCl, 2 mM Ca+2, 0.8 mM Mg+2, pH ~8.0 ±0.5, 37 °C), as this is estimated to generate the [Ca+2] & [PO4-3] required to form the apatite content of bone tissue

Alveolar bone repair with strontium- containing nanostructured carbonated hydroxyapatite

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André Boziki Xavier do Carmo

2018-01-01

Full Text Available ABSTRACT Objective: This study aimed to evaluate bone repair in rat dental sockets after implanting nanostructured carbonated hydroxyapatite/sodium alginate (CHA and nanostructured carbonated hydroxyapatite/sodium alginate containing 5% strontium microspheres (SrCHA as bone substitute materials. Methods: Twenty male Wistar rats were randomly divided into two experimental groups: CHA and SrCHA (n=5/period/group. After one and 6 weeks of extraction of the right maxillary central incisor and biomaterial implantation, 5 μm bone blocks were obtained for histomorphometric evaluation. The parameters evaluated were remaining biomaterial, loose connective tissue and newly formed bone in a standard area. Statistical analysis was performed by Mann-Withney and and Wilcoxon tests at 95% level of significance. Results: The histomorphometric results showed that the microspheres showed similar fragmentation and bio-absorbation (p>0.05. We observed the formation of new bones in both groups during the same experimental periods; however, the new bone formation differed significantly between the weeks 1 and 6 (p=0.0039 in both groups. Conclusion: The CHA and SrCHA biomaterials were biocompatible, osteoconductive and bioabsorbable, indicating their great potential for clinical use as bone substitutes.

Formation of an ascorbate-apatite composite layer on titanium

Energy Technology Data Exchange (ETDEWEB)

Ito, Atsuo [National Institute of Advanced Industrial Science and Technology (AIST), Institute for Human Science and Biomedical Engineering, Central 6, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566 (Japan); Sogo, Yu [National Institute of Advanced Industrial Science and Technology (AIST), Institute for Human Science and Biomedical Engineering, Central 6, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566 (Japan); Ebihara, Yuko [School of Science and Technology, Waseda University, 3-4-1 Okubo, Sinjuku-ku, Tokyo 169-8050 (Japan); Onoguchi, Masahiro [School of Science and Technology, Waseda University, 3-4-1 Okubo, Sinjuku-ku, Tokyo 169-8050 (Japan); Oyane, Ayako [National Institute of Advanced Industrial Science and Technology (AIST), Nanotechnology Research Institute, Central 4, Higashi 1-1-1, Tsukuba, Ibaraki 305-8562 (Japan); Ichinose, Noboru [School of Science and Technology, Waseda University, 3-4-1 Okubo, Sinjuku-ku, Tokyo 169-8050 (Japan)

2007-09-15

An ascorbate-apatite composite layer was successfully formed on NaOH- and heat-treated titanium by coprecipitating L-ascorbic acid phosphate and low-crystalline apatite in a supersaturated calcium phosphate solution at 37 {sup 0}C for 48 h. The supersaturated calcium phosphate solutions used have chemical compositions attainable by mixing infusion fluids officially approved for clinical use. The amount of immobilized L-ascorbic acid phosphate ranged from 1.0 to 2.3 {mu}g mm{sup -2}, which is most likely to be sufficient for the in vitro osteogenic differentiation of mesenchymal stem cells on titanium. Since ascorbate is important for the collagen synthesis and subsequent osteogenesis of mesenchymal stem cells, titanium coated with the ascorbate-apatite composite layer would be useful as a scaffold in bone tissue engineering and as a bone substitute.

Formation of an ascorbate-apatite composite layer on titanium

International Nuclear Information System (INIS)

Ito, Atsuo; Sogo, Yu; Ebihara, Yuko; Onoguchi, Masahiro; Oyane, Ayako; Ichinose, Noboru

2007-01-01

An ascorbate-apatite composite layer was successfully formed on NaOH- and heat-treated titanium by coprecipitating L-ascorbic acid phosphate and low-crystalline apatite in a supersaturated calcium phosphate solution at 37 0 C for 48 h. The supersaturated calcium phosphate solutions used have chemical compositions attainable by mixing infusion fluids officially approved for clinical use. The amount of immobilized L-ascorbic acid phosphate ranged from 1.0 to 2.3 μg mm -2 , which is most likely to be sufficient for the in vitro osteogenic differentiation of mesenchymal stem cells on titanium. Since ascorbate is important for the collagen synthesis and subsequent osteogenesis of mesenchymal stem cells, titanium coated with the ascorbate-apatite composite layer would be useful as a scaffold in bone tissue engineering and as a bone substitute

Hydrothermal Synthesis and Biocompatibility Study of Highly Crystalline Carbonated Hydroxyapatite Nanorods

Science.gov (United States)

Xue, Caibao; Chen, Yingzhi; Huang, Yongzhuo; Zhu, Peizhi

2015-08-01

Highly crystalline carbonated hydroxyapatite (CHA) nanorods with different carbonate contents were synthesized by a novel hydrothermal method. The crystallinity and chemical structure of synthesized nanorods were studied by Fourier transform infrared spectroscopy (FTIR), X-ray photo-electronic spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). The biocompatibility of synthesized CHA nanorods was evaluated by cell viability and alkaline phosphatase (ALP) activity of MG-63 cell line. The biocompatibility evaluation results show that these CHA nanorods are biologically active apatites and potentially promising bone-substitute biomaterials for orthopedic application.

Single-crystal apatite nanowires sheathed in graphitic shells: synthesis, characterization, and application.

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Jeong, Namjo; Cha, Misun; Park, Yun Chang; Lee, Kyung Mee; Lee, Jae Hyup; Park, Byong Chon; Lee, Junghoon

2013-07-23

Vertically aligned one-dimensional hybrid structures, which are composed of apatite and graphitic structures, can be beneficial for orthopedic applications. However, they are difficult to generate using the current method. Here, we report the first synthesis of a single-crystal apatite nanowire encapsulated in graphitic shells by a one-step chemical vapor deposition. Incipient nucleation of apatite and its subsequent transformation to an oriented crystal are directed by derived gaseous phosphorine. Longitudinal growth of the oriented apatite crystal is achieved by a vapor-solid growth mechanism, whereas lateral growth is suppressed by the graphitic layers formed through arrangement of the derived aromatic hydrocarbon molecules. We show that this unusual combination of the apatite crystal and the graphitic shells can lead to an excellent osteogenic differentiation and bony fusion through a programmed smart behavior. For instance, the graphitic shells are degraded after the initial cell growth promoted by the graphitic nanostructures, and the cells continue proliferation on the bare apatite nanowires. Furthermore, a bending experiment indicates that such core-shell nanowires exhibited a superior bending stiffness compared to single-crystal apatite nanowires without graphitic shells. The results suggest a new strategy and direction for bone grafting materials with a highly controllable morphology and material conditions that can best stimulate bone cell differentiation and growth.

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

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

International Nuclear Information System (INIS)

Iafisco, Michele; Ruffini, Andrea; Adamiano, Alessio; Sprio, Simone; Tampieri, Anna

2014-01-01

The present work investigates the preparation of biomimetic nanocrystalline apatites co-substituted with Mg, CO 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 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 3 -apatite. Indeed, incorporation of lower quantity of Sr did not induce considerable variations in the chemical structure of Mg–CO 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 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 3 and Sr were prepared. • Biological-like amounts of Mg and CO 3 were inserted to mimic the composition of bone apatite. • The addition of increasing quantities of Sr (from 0 to 12

Simultaneous incorporation of carbonate and fluoride in synthetic apatites: Effect on crystallographic and physico-chemical properties.

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Yao, Fang; LeGeros, John P; LeGeros, Racquel Z

2009-07-01

The mineral in bone is an impure hydroxyapatite, with carbonate as the chief minor substituent. Fluoride has been shown to stimulate osteoblastic activity and inhibit osteoclastic resorption in vitro. CO(3)- and F-substituted apatite (CFA) has been considered as potential bone graft material for orthopedic and dental applications. The objective of this study was to determine the effects of simultaneously incorporated CO(3) and F on the crystallographic physico-chemical properties of apatite. The results showed that increasing CO(3) and Na content in apatites with relatively constant F concentration caused a decrease in crystallite size and an increase in the extent of calcium release; increasing F content in apatites with relatively constant CO(3) concentration caused an increase in crystallite size and a decrease in the extent of Ca release. These findings suggest that CFAs as bone graft materials of desired solubility can be prepared by manipulating the relative concentrations of CO(3) and F incorporated in the apatite.

Thermodynamic basis for evolution of apatite in calcified tissues (Invited)

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Navrotsky, A.; Drouet, C.; Rollin-Martinet, S.; Champion, E.; Grossin, D.

2013-12-01

Bone remodeling and tooth enamel maturation are biological processes which alter the physico-chemical features of biominerals with time. However, although the ubiquity of bone remodeling is clear, why is well crystallized bone mineral systematically replaced by immature nanocrystalline inorganic material? In enamel, a clear evolution is also seen from the first mineral formed during the secretory stage to its mature well crystalline form, which then changes little in the adult tooth. This contribution provides the thermodynamic basis underlying these biological processes. We determined the energetics of biomimetic apatites corresponding to an increasing degree of maturation. Our data point out the progressive evolution of the enthalpy (ΔHf°) and free energy (ΔGf°) of formation toward more negative values upon maturation. Entropy contributions to ΔGf° values are small compared to enthalpy contributions. ΔHf° varies from -12058.9 × 12.2 to -12771.0 × 21.4 kJ/mol for maturation times increasing from 20 min to 3 weeks, approaching the value for stoichiometric hydroxyapatite, -13431.0 × 22.7 kJ/mol. Apatite thermodynamic stability increases as its composition moved toward stoichiometry. These findings imply diminishing aqueous solubility of calcium and phosphate ions as well as decreased surface reactivity. Such thermodynamically-driven maturation is favorable for enamel maturation since this biomineral must resist external aggressions such as contact with acids. In contrast, maintaining a metastable highly reactive and soluble form of apatite is essential to the effective participation of bone as a source of calcium and phosphate for homeostasis. Therefore our data strongly suggest that, far from being trivial, the intrinsic thermodynamic properties of apatite represent a critical driving force for continuous bone remodeling, in contrast to current views favoring a purely biologically driven cycle. These thermodynamic data may prove helpful in other domains

BMP4 Expression Following Stem Cells from Human Exfoliated Deciduous and Carbonate Apatite Transplantation on Rattus norvegicus

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Tania Saskianti

2018-04-01

Full Text Available Background: Alveolar bone defects in children still have a high incidence. Conventional bone graft technique that has been used as a defect therapy is still not effective, so new techniques with tissue engineering approach are needed. Bone Morphogenetic Protein 4 (BMP4 as one of the indicators of osteogenic differentiation has not been widely studied, especially in the transplantation with combination of Stem Cells from Human Exfoliated Deciduous (SHED and carbonate apatite. Aim and Objectives: This research aimed to determine the expression of BMP4 after SHED and carbonate apatite transplantation on Rattus norvegicus. Material and Methods: The combinations of SHED and carbonate apatite were transplanted on alveolar bone defects of 4 rats (Rattus norvegicus as the treatment groups and another 4 rats were transplanted with carbonate apatite as the control groups. After 21 days, staining with Hematoxylin Eosin (HE and Immunohistochemistry (IHC BMP4 was performed. Results: BMP4 expression in the treatment groups was significantly higher when compared to the control groups. Discussion: Carbonate apatite has low crystallization rate and high osteoconductivity that produce more osteoblasts and increased BMP4 expression. Conclusion: The transplantation of SHED and carbonate apatite increased BMP4 expression as an indicator of osteogenic differentiation in rats.

Interconnected porous hydroxyapatite ceramics for bone tissue engineering

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Yoshikawa, Hideki; Tamai, Noriyuki; Murase, Tsuyoshi; Myoui, Akira

2008-01-01

Several porous calcium hydroxyapatite (HA) ceramics have been used clinically as bone substitutes, but most of them possessed few interpore connections, resulting in pathological fracture probably due to poor bone formation within the substitute. We recently developed a fully interconnected porous HA ceramic (IP-CHA) by adopting the ‘foam-gel’ technique. The IP-CHA had a three-dimensional structure with spherical pores of uniform size (average 150 μm, porosity 75%), which were interconnected by window-like holes (average diameter 40 μm), and also demonstrated adequate compression strength (10–12 MPa). In animal experiments, the IP-CHA showed superior osteoconduction, with the majority of pores filled with newly formed bone. The interconnected porous structure facilitates bone tissue engineering by allowing the introduction of mesenchymal cells, osteotropic agents such as bone morphogenetic protein or vasculature into the pores. Clinically, we have applied the IP-CHA to treat various bony defects in orthopaedic surgery, and radiographic examinations demonstrated that grafted IP-CHA gained radiopacity more quickly than the synthetic HA in clinical use previously. We review the accumulated data on bone tissue engineering using the novel scaffold and on clinical application in the orthopaedic field. PMID:19106069

Evaluating Community Health Advisor (CHA) Core Competencies: The CHA Core Competency Retrospective Pretest/Posttest (CCCRP).

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Story, Lachel; To, Yen M

2016-05-01

Health care and academic systems are increasingly collaborating with community health advisors (CHAs) to provide culturally relevant health interventions that promote sustained community transformation. Little attention has been placed on CHA training evaluation, including core competency attainment. This study identified common CHA core competencies, generated a theoretically based measure of those competencies, and explored psychometric properties of that measure. A concept synthesis revealed five CHA core competencies (leadership, translation, guidance, advocacy, and caring). The CHA Core Competency Retrospective Pretest/Posttest (CCCRP) resulted from that synthesis, which was administered using multiple approaches to individuals who previously received CHA training (N= 142). Exploratory factor analyses revealed a two-factor structure underlying the posttraining data, and Cronbach's alpha indicated high internal consistency. This study suggested some CHA core competencies might be more interrelated than previously thought, and two major competencies exist rather than five and supported the CCCRP's use to evaluate core competency attainment resulting from training. © The Author(s) 2014.

Investigation of the histology and interfacial bonding between carbonated hydroxyapatite cement and bone

International Nuclear Information System (INIS)

Mao Keya; Hao Libo; Tang Peifu; Wang Zheng; Wen Ning; Du Mingkui; Wang Jifang; Wang Yan; Yang Yun; Li Jiangtao

2009-01-01

An ideal bone implant should facilitate the formation of a new bone layer as an osteo-integrated interface between bone and the implanted biomaterials. In the present work, the interface between carbonated hydroxyapatite (CHA) cement and bone was evaluated by interfacial bonding strength measurements and histological characterizations. CHA cement was implanted into a mongrel dog's femoral supracondylar and below the tibial plateau area, and was then tested ex vivo by, respectively, detaching and pullout experiments. Polymethylmethacrylate (PMMA) was used as a control. CHA cement could be directly injected and solidified in situ to repair bone defects. Histology results showed that CHA bonded with bone through gradual remodeling and was replaced by new bone tissue, which is an attribute for excellent biocompatibility. The interfacial bonding strength increased with implantation time. After 16 weeks implantation, the measured detaching force and the pullout force between CHA and bone were 281 ± 16 N and 512.5 ± 14.5 N, respectively. These values were several times higher compared to 5 days implantation. In contrast, the control showed a fibrous microstructure between PMMA and bone, and the detaching force and the pullout force decreased with implantation time. The results strongly suggest that CHA can form a better osteo-integrated interface compared to PMMA, and could be used as an ideal biomaterial for bone defect repair.

Biomimetic scaffolds based on hydroxyapatite nanorod/poly(D,L) lactic acid with their corresponding apatite-forming capability and biocompatibility for bone-tissue engineering.

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Nga, Nguyen Kim; Hoai, Tran Thanh; Viet, Pham Hung

2015-04-01

This study presents a facile synthesis of biomimetic hydroxyapatite nanorod/poly(D,L) lactic acid (HAp/PDLLA) scaffolds with the use of solvent casting combined with a salt-leaching technique for bone-tissue engineering. Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy were used to observe the morphologies, pore structures of synthesized scaffolds, interactions between hydroxyapatite nanorods and poly(D,L) lactic acid, as well as the compositions of the scaffolds, respectively. Porosity of the scaffolds was determined using the liquid substitution method. Moreover, the apatite-forming capability of the scaffolds was evaluated through simulated body fluid (SBF) incubation tests, whereas the viability, attachment, and distribution of human osteoblast cells (MG 63 cell line) on the scaffolds were determined through alamarBlue assay and confocal laser microscopy after nuclear staining with 4',6-diamidino-2-phenylindole and actin filaments of a cytoskeleton with Oregon Green 488 phalloidin. Results showed that hydroxyapatite nanorod/poly(D,L) lactic acid scaffolds that mimic the structure of natural bone were successfully produced. These scaffolds possessed macropore networks with high porosity (80-84%) and mean pore sizes ranging 117-183 μm. These scaffolds demonstrated excellent apatite-forming capabilities. The rapid formation of bone-like apatites with flower-like morphology was observed after 7 days of incubation in SBFs. The scaffolds that had a high percentage (30 wt.%) of hydroxyapatite demonstrated better cell adhesion, proliferation, and distribution than those with low percentages of hydroxyapatite as the days of culture increased. This work presented an efficient route for developing biomimetic composite scaffolds, which have potential applications in bone-tissue engineering. Copyright © 2015 Elsevier B.V. All rights reserved.

Restoran Cha Dao = Restaurant Cha Dao

Index Scriptorium Estoniae

2012-01-01

Tallinnas Suur-Patarei 2 asuva Hiina restorani Cha Dao sisekujundusest. Restorani mööbel, v.a toolid, projekteeriti eritellimusena. Sisearhitekt Dmitri Pisarenko (DM3 OÜ), loetletud tema töid. Arhitekt Meeli Truu

[Synthesis and characterization of CO-3(2-) doping nano-hydroxyapatite].

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Liao, Jian-Guo; Li, Yan-Qun; Duan, Xing-Ze; Liu, Qiong

2014-11-01

CO3(2-) doping is an effective method to increase the biological activity of nano-hydroxyapatite (n-HA). In the present study, calcium nitrate and trisodium phosphate were chosen as raw materials, with a certain amount of Na2CO3 as a source of CO-3(2-) ions, to synthesize nano-carbonate hydroxyapatite (n-CHA) slurry by solution precipitation method. The structure and micro-morphology of n-CHA were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR) and Raman spectroscopy (RS). The results revealed that the synthetic n-HA crystals are acicular in nanometer scale and have a crystal size of 20-30 nm in diameter and 60-80 nm in length, which are similar to natural bone apatite. And the crystallinity of n-CHA crystals decreases to the increment of CO3(2-). Samples with more CO3(2) have composition and structure more similar to the bone apatite. The value of lattice parameters a decreases, value of c increases, and c/a value increases with the increase in the amount of CO3(2-), in accordance with crystal cell parameters change rule of type B replacement. In the AB mixed type (substitution OH- and PO4(3-)) CHA, IR characteristic peak of CO3(2-) out-of-plane bending vibration appears at 872 cm(-1), meanwhile, the asymmetry flexible vibration band is split into band at 1 454 cm(-1) and band at 1 420 cm(-1), while weak CO3(2)-peak appears at 1 540 cm(-1). CO3(2-) Raman peak of symmetric stretching vibration appears at 1 122 cm(-1). CO3(2-) B-type (substitution PO4(3-)) peak appeared at 1 071 cm(-1). Through the calculation of integral area ratio of PO4(3-)/ CO3(2-), OH-/CO3(2-), and PO4(3-)/OH-, low quantity CO3(2-) is B-type and high quantity CO3(2-) is A-type (substitution OH-). The results show that the synthesized apatite crystals are AB hybrid substitued nano-carbonate hydroxyapatite, however B-type replacement is the main substitute mode. Due to similarity inthe shape, size, crystal structure

Study on apatite compounds; Apataitokei kagobutsu ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-11-28

To clarify the material properties of apatite compounds, the synthesis method, and the evaluation of physical properties of material and elementary technology were investigated. For the study on synthesis and crystal growth, a method of precipitating calcium phosphate on the surface of metal was investigated by means of relatively mild electrolytic method using liquid phase system. A new molding method of Ca defective apatite was established. Composite similar to vital bone was prepared by means of a new low-temperature sintering. For the study on chemical properties, from the model experiments, it was found that the self-organizing phenomenon, which is observed in the composite of apatite and collagen, happened between the organic single molecular film and crystal of apatite. For the study on evaluation of physical properties and elementary technology, the surface and interface of ceramics such as apatite were investigated by means of spectroscopy, the electronic state was analyzed by the quantum chemical calculation, and the crystalline structure was analyzed using X-ray equipment. 270 refs., 102 figs., 10 tabs.

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

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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

Cytocompatibility and biocompatibility of nanostructured carbonated hydroxyapatite spheres for bone repair

Science.gov (United States)

CALASANS-MAIA, Mônica Diuana; de MELO, Bruno Raposo; ALVES, Adriana Terezinha Neves Novellino; RESENDE, Rodrigo Figueiredo de Brito; LOURO, Rafael Seabra; SARTORETTO, Suelen Cristina; GRANJEIRO, José Mauro; ALVES, Gutemberg Gomes

2015-01-01

ABSTRACT Objective The aim of this study was to investigate the in vitro and in vivo biological responses to nanostructured carbonated hydroxyapatite/calcium alginate (CHA) microspheres used for alveolar bone repair, compared to sintered hydroxyapatite (HA). Material and Methods The maxillary central incisors of 45 Wistar rats were extracted, and the dental sockets were filled with HA, CHA, and blood clot (control group) (n=5/period/group). After 7, 21 and 42 days, the samples of bone with the biomaterials were obtained for histological and histomorphometric analysis, and the plasma levels of RANKL and OPG were determined via immunoassay. Statistical analysis was performed by Two-Way ANOVA with post-hoc Tukey test at 95% level of significance. Results The CHA and HA microspheres were cytocompatible with both human and murine cells on an in vitro assay. Histological analysis showed the time-dependent increase of newly formed bone in control group characterized by an intense osteoblast activity. In HA and CHA groups, the presence of a slight granulation reaction around the spheres was observed after seven days, which was reduced by the 42nd day. A considerable amount of newly formed bone was observed surrounding the CHA spheres and the biomaterials particles at 42-day time point compared with HA. Histomorphometric analysis showed a significant increase of newly formed bone in CHA group compared with HA after 21 and 42 days from surgery, moreover, CHA showed almost 2-fold greater biosorption than HA at 42 days (two-way ANOVA, p<0.05) indicating greater biosorption. An increase in the RANKL/OPG ratio was observed in the CHA group on the 7th day. Conclusion CHA spheres were osteoconductive and presented earlier biosorption, inducing early increases in the levels of proteins involved in resorption. PMID:26814461

Cytocompatibility and biocompatibility of nanostructured carbonated hydroxyapatite spheres for bone repair

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Mônica Diuana CALASANS-MAIA

2015-12-01

Full Text Available ABSTRACT Objective The aim of this study was to investigate the in vitro and in vivo biological responses to nanostructured carbonated hydroxyapatite/calcium alginate (CHA microspheres used for alveolar bone repair, compared to sintered hydroxyapatite (HA. Material and Methods The maxillary central incisors of 45 Wistar rats were extracted, and the dental sockets were filled with HA, CHA, and blood clot (control group (n=5/period/group. After 7, 21 and 42 days, the samples of bone with the biomaterials were obtained for histological and histomorphometric analysis, and the plasma levels of RANKL and OPG were determined via immunoassay. Statistical analysis was performed by Two-Way ANOVA with post-hoc Tukey test at 95% level of significance. Results The CHA and HA microspheres were cytocompatible with both human and murine cells on an in vitro assay. Histological analysis showed the time-dependent increase of newly formed bone in control group characterized by an intense osteoblast activity. In HA and CHA groups, the presence of a slight granulation reaction around the spheres was observed after seven days, which was reduced by the 42nd day. A considerable amount of newly formed bone was observed surrounding the CHA spheres and the biomaterials particles at 42-day time point compared with HA. Histomorphometric analysis showed a significant increase of newly formed bone in CHA group compared with HA after 21 and 42 days from surgery, moreover, CHA showed almost 2-fold greater biosorption than HA at 42 days (two-way ANOVA, p<0.05 indicating greater biosorption. An increase in the RANKL/OPG ratio was observed in the CHA group on the 7th day. Conclusion CHA spheres were osteoconductive and presented earlier biosorption, inducing early increases in the levels of proteins involved in resorption.

Photoluminescence in the characterization and early detection of biomimetic bone-like apatite formation on the surface of alkaline-treated titanium implant: state of the art.

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Sepahvandi, Azadeh; Moztarzadeh, Fathollah; Mozafari, Masoud; Ghaffari, Maryam; Raee, Nahid

2011-09-01

Photoluminescence (PL) property is particularly important in the characterization of materials that contain significant proportions of noncrystalline components, multiple phases, or low concentrations of mineral phases. In this research, the ability of biomimetic bone-like apatite deposition on the surface of titanium alloy (Ti6Al4V) substrates in simulated body fluid (SBF) right after alkaline-treatment and subsequent heat-treatment was studied by the inherent luminescence properties of apatite. For this purpose, the metallic substrates were treated in 5 M NaOH solution at 60 °C. Subsequently, the substrates were heat-treated at 600 °C for 1 h for consolidation of the sodium titanate hydrogel layer. Then, they were soaked in SBF for different periods of time. Finally, the possibility to use of PL monitoring as an effective method and early detection tool is discussed. According to the obtained results, it was concluded that the PL emission peak did not have any significant shift to the shorter or higher wavelengths, and the PL intensity increased as the exposure time increased. This research proved that the observed inherent PL of the newly formed apatite coatings might be of specific interest for histological probing and bone remodelling monitoring. Copyright © 2011 Elsevier B.V. All rights reserved.

Effects of LED phototherapy on bone defects grafted with MTA, bone morphogenetic proteins and guided bone regeneration: a Raman spectroscopic study.

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Pinheiro, Antonio L B; Soares, Luiz G P; Cangussú, Maria Cristina T; Santos, Nicole R S; Barbosa, Artur Felipe S; Silveira Júnior, Landulfo

2012-09-01

We studied peaks of calcium hydroxyapatite (CHA) and protein and lipid CH groups in defects grafted with mineral trioxide aggregate (MTA) treated or not with LED irradiation, bone morphogenetic proteins and guided bone regeneration. A total of 90 rats were divided into ten groups each of which was subdivided into three subgroups (evaluated at 15, 21 and 30 days after surgery). Defects were irradiated with LED light (wavelength 850 ± 10 nm) at 48-h intervals for 15 days. Raman readings were taken at the surface of the defects. There were no statistically significant differences in the CHA peaks among the nonirradiated defects at any of the experimental time-points. On the other hand, there were significant differences between the defects filled with blood clot and the irradiated defects at all time-points (p Raman spectral analysis indicate that infrared LED light irradiation improves the deposition of CHA in healing bone grafted or not with MTA.

Menopause and big data: Word Adjacency Graph modeling of menopause-related ChaCha data.

Science.gov (United States)

Carpenter, Janet S; Groves, Doyle; Chen, Chen X; Otte, Julie L; Miller, Wendy R

2017-07-01

To detect and visualize salient queries about menopause using Big Data from ChaCha. We used Word Adjacency Graph (WAG) modeling to detect clusters and visualize the range of menopause-related topics and their mutual proximity. The subset of relevant queries was fully modeled. We split each query into token words (ie, meaningful words and phrases) and removed stopwords (ie, not meaningful functional words). The remaining words were considered in sequence to build summary tables of words and two and three-word phrases. Phrases occurring at least 10 times were used to build a network graph model that was iteratively refined by observing and removing clusters of unrelated content. We identified two menopause-related subsets of queries by searching for questions containing menopause and menopause-related terms (eg, climacteric, hot flashes, night sweats, hormone replacement). The first contained 263,363 queries from individuals aged 13 and older and the second contained 5,892 queries from women aged 40 to 62 years. In the first set, we identified 12 topic clusters: 6 relevant to menopause and 6 less relevant. In the second set, we identified 15 topic clusters: 11 relevant to menopause and 4 less relevant. Queries about hormones were pervasive within both WAG models. Many of the queries reflected low literacy levels and/or feelings of embarrassment. We modeled menopause-related queries posed by ChaCha users between 2009 and 2012. ChaCha data may be used on its own or in combination with other Big Data sources to identify patient-driven educational needs and create patient-centered interventions.

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

Energy Technology Data Exchange (ETDEWEB)

Yu, Peng [National engineering research center for tissue restoration and reconstruction, South China University of Technology, Guangzhou 510641 (China); Lu, Fang [School of Chinese Materia Medica, Guangzhou University of Chinese Medicine, Guangzhou 510006 (China); Zhu, Wenjun [Department of Prosthodontics, Guanghua School of Stomatology, Guang Dong Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China); Wang, Di [National engineering research center for tissue restoration and reconstruction, South China University of Technology, Guangzhou 510641 (China); Zhu, Xiaojing [Department of Prosthodontics, Guanghua School of Stomatology, Guang Dong Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China); Tan, Guoxin, E-mail: tanguoxin@126.com [Institute of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006 (China); Wang, Xiaolan [National engineering research center for tissue restoration and reconstruction, South China University of Technology, Guangzhou 510641 (China); Zhang, Yu; Li, Lihua [General Hospital of Guangzhou Military Command of PLA, Guangzhou 510010 (China); Ning, Chengyun, E-mail: imcyning@scut.edu.cn [National engineering research center for tissue restoration and reconstruction, South China University of Technology, Guangzhou 510641 (China)

2014-09-15

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 CO{sub 3}{sup 2−} 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 CO{sub 3}{sup 2−} incorporation rate in apatite coating was quantitatively examined by bending vibration of CO{sub 3}{sup 2−} at ∼874 cm{sup −1}. Results indicated the highest carbonate content was obtained at the citrate ion concentration of 6 × 10{sup −5} mol/L in SC-SBF. These three-dimensional porous titanium-apatite hybrid scaffolds are expected to find application in bone tissue regeneration.

Application of interconnected porous hydroxyapatite ceramic block for onlay block bone grafting in implant treatment: A case report.

Science.gov (United States)

Ohta, Kouji; Tada, Misato; Ninomiya, Yoshiaki; Kato, Hiroki; Ishida, Fumi; Abekura, Hitoshi; Tsuga, Kazuhiro; Takechi, Masaaki

2017-12-01

Autogenous block bone grafting as treatment for alveolar ridge atrophy has various disadvantages, including a limited availability of sufficiently sized and shaped grafts, donor site morbidity and resorption of the grafted bone. As a result, interconnected porous hydroxyapatite ceramic (IP-CHA) materials with high porosity have been developed and used successfully in orthopedic cases. To the best of the author's knowledge, this is the first report of clinical application of an IP-CHA block for onlay grafting for implant treatment in a patient with horizontal alveolar atrophy. The present study performed onlay block grafting using an IP-CHA block to restore bone volume for implant placement in the alveolar ridge area without collecting autogenous bone. Dental X-ray findings revealed that the border of the IP-CHA block became increasingly vague over the 3-year period, whereas CT scanning revealed that the gap between the block and bone had a smooth transition, indicating that IP-CHA improved the process of integration with host bone. In follow-up examinations over a period of 5 years, the implants and superstructures had no problems. An IP-CHA block may be useful as a substitute for onlay block bone grafting in implant treatment.

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.

Apatite-mediated actin dynamics in resorbing osteoclasts.

Science.gov (United States)

Saltel, Frédéric; Destaing, Olivier; Bard, Frédéric; Eichert, Diane; Jurdic, Pierre

2004-12-01

The actin cytoskeleton is essential for osteoclasts main function, bone resorption. Two different organizations of actin have been described in osteoclasts, the podosomes belt corresponding to numerous F-actin columns arranged at the cell periphery, and the sealing zone defined as a unique large band of actin. To compare the role of these two different actin organizations, we imaged osteoclasts on various substrata: glass, dentin, and apatite. Using primary osteoclasts expressing GFP-actin, we found that podosome belts and sealing zones, both very dynamic actin structures, were present in mature osteoclasts; podosome belts were observed only in spread osteoclasts adhering onto glass, whereas sealing zone were seen in apico-basal polarized osteoclasts adherent on mineralized matrix. Dynamic observations of several resorption cycles of osteoclasts seeded on apatite revealed that 1) podosomes do not fuse together to form the sealing zone; 2) osteoclasts alternate successive stationary polarized resorption phases with a sealing zone and migration, nonresorption phases without any specific actin structure; and 3) apatite itself promotes sealing zone formation though c-src and Rho signaling. Finally, our work suggests that apatite-mediated sealing zone formation is dependent on both c-src and Rho whereas apico-basal polarization requires only Rho.

Developing bioactive composite scaffolds for bone tissue engineering

Science.gov (United States)

Chen, Yun

Poly(L-lactic acid) (PLLA) films were fabricated using the method of dissolving and evaporation. PLLA scaffold was prepared by solid-liquid phase separation of polymer solutions and subsequent sublimation of solvent. Bonelike apatite coating was formed on PLLA films, PLLA scaffolds and poly(glycolic acid) (PGA) scaffolds in 24 hours through an accelerated biomimetic process. The ion concentrations in the simulated body fluid (SBF) were nearly 5 times of those in human blood plasma. The apatite formed was characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The apatite formed in 5SBF was similar in morphology and composition to that formed in the classical biomimetic process employing SBF or 1.5SBF, and similar to that of natural bone. This indicated that the biomimetic apatite coating process could be accelerated by using concentrated simulated body fluid at 37°C. Besides saving time, the accelerated biomimetic process is particularly significant to biodegradable polymers. Some polymers which degrade too fast to be coated with apatite by a classical biomimetic process, for example PGA, could be coated with bone-like apatite in an accelerated biomimetic process. Collagen and apatite were co-precipitated as a composite coating on poly(L-lactic acid) (PLLA) in an accelerated biomimetic process. The incubation solution contained collagen (1g/L) and simulated body fluid (SBF) with 5 times inorganic ionic concentrations as human blood plasma. The coating formed on PLLA films and scaffolds after 24 hours incubation was characterized using EDX, XRD, FTIR, and SEM. It was shown that the coating contained carbonated bone-like apatite and collagen, the primary constituents of natural bone. SEM showed a complex composite coating of submicron bone-like apatite particulates combined with collagen fibrils. This work provided an efficient process to obtain

Biomimetic composite coating on rapid prototyped scaffolds for bone tissue engineering.

Science.gov (United States)

Arafat, M Tarik; Lam, Christopher X F; Ekaputra, Andrew K; Wong, Siew Yee; Li, Xu; Gibson, Ian

2011-02-01

The objective of this present study was to improve the functional performance of rapid prototyped scaffolds for bone tissue engineering through biomimetic composite coating. Rapid prototyped poly(ε-caprolactone)/tri-calcium phosphate (PCL/TCP) scaffolds were fabricated using the screw extrusion system (SES). The fabricated PCL/TCP scaffolds were coated with a carbonated hydroxyapatite (CHA)-gelatin composite via biomimetic co-precipitation. The structure of the prepared CHA-gelatin composite coating was studied by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Compressive mechanical testing revealed that the coating process did not have any detrimental effect on the mechanical properties of the scaffolds. The cell-scaffold interaction was studied by culturing porcine bone marrow stromal cells (BMSCs) on the scaffolds and assessing the proliferation and bone-related gene and protein expression capabilities of the cells. Confocal laser microscopy and SEM images of the cell-scaffold constructs showed a uniformly distributed cell sheet and accumulation of extracellular matrix in the interior of CHA-gelatin composite-coated PCL/TCP scaffolds. The proliferation rate of BMSCs on CHA-gelatin composite-coated PCL/TCP scaffolds was about 2.3 and 1.7 times higher than that on PCL/TCP scaffolds and CHA-coated PCL/TCP scaffolds, respectively, by day 10. Furthermore, reverse transcription polymerase chain reaction and Western blot analysis revealed that CHA-gelatin composite-coated PCL/TCP scaffolds stimulate osteogenic differentiation of BMSCs the most, compared with PCL/TCP scaffolds and CHA-coated PCL/TCP scaffolds. These results demonstrate that CHA-gelatin composite-coated rapid prototyped PCL/TCP scaffolds are promising for bone tissue engineering. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

[Experimental study of the effect of new bone formation on new type artificial bone composed of bioactive ceramics].

Science.gov (United States)

Zhu, Minghua; Zeng, Yi; Sun, Tao; Peng, Qiang

2005-03-15

To investigate the osteogenic potential of four kinds of new bioactive ceramics combined with bovine bone morphogenetic proteins (BMP) and to explore the feasibility of using compounds as bone substitute material. Ninety-six rats were divided into 4 groups (24 in each group). BMP was combined with hydroxyapatite (HA), tricalcium phosphate (TCP), fluoridated-HA (FHA), and collagen-HA(CHA) respectively. The left thighs of the rats implanted with HA/BMP, TCP/BMP, FHA/BMP, and CHA/BMP were used as experimental groups. The right thighs of the rats implanted with HA, TCP, CHA, and decalcified dentin matrix (DDM) were used as control groups. The rats were sacrificed 1, 3, 5 and 7 weeks after implantation and bone induction was estimated by alkaline phosphatase (ALP), phosphorus (P), and total protein (TP) measurement. The histological observation and electronic microscope scanning of the implants were also made. The cartilage growth in the 4 experimental groups and the control group implanted with DDM was observed 1 week after operation and fibrous connective tissues were observed in the other 3 control groups. 3 weeks after implantation, lamellar bone with bone marrow and positive reaction in ALP stain were observed in the 4 experimental groups. No bone formation or positive reaction in ALP stain were observed in the control groups. The amount of ALP activity, P value, and new bone formation in the experimental groups were higher than those in the control group(P < 0.05). The amount of ALP activity, P value, and new bone formation in TCP/BMP group were higher than those in HA/BMP, CHA/BMP and FHA/BMP groups (P < 0.05). There was no significant difference in TP between the BMP treatment group and the control groups. From 5th to 7th week, new bone formation, histochemistry evaluation, and the level of ALP, P, TP value were as high as those in the 3rd week. New composite artificial bone of TCP/BMP, HA/BMP, CHA/BMP, and FHA/BMP all prove to be effective, but TCP/BMP is the

Dicty_cDB: CHA557 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available CH (Link to library) CHA557 (Link to dictyBase) - - - Contig-U15635-1 - (Link to Or...iginal site) CHA557F 620 - - - - - - Show CHA557 Library CH (Link to library) Clone ID CHA557 (Link to dicty...Base) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U15635-1 Original site URL http://dictycdb.b...HSIEIGKVEILPNSLIGIDEDGVIQHMKSN YEDLKQLEKDVTMICTDNGINEQESVIDMGNKFLIPGFIDTHAHAPQYHNAGTGTDLPLL KWLEKYTFPVESKFKD...EIGKVEILPNSLIGIDEDGVIQHMKSN YEDLKQLEKDVTMICTDNGINEQESVIDMGNKFLIPGFIDTHAHAPQYHNAGT

Bone regeneration performance of surface-treated porous titanium.

Science.gov (United States)

Amin Yavari, Saber; van der Stok, Johan; Chai, Yoke Chin; Wauthle, Ruben; Tahmasebi Birgani, Zeinab; Habibovic, Pamela; Mulier, Michiel; Schrooten, Jan; Weinans, Harrie; Zadpoor, Amir Abbas

2014-08-01

The large surface area of highly porous titanium structures produced by additive manufacturing can be modified using biofunctionalizing surface treatments to improve the bone regeneration performance of these otherwise bioinert biomaterials. In this longitudinal study, we applied and compared three types of biofunctionalizing surface treatments, namely acid-alkali (AcAl), alkali-acid-heat treatment (AlAcH), and anodizing-heat treatment (AnH). The effects of treatments on apatite forming ability, cell attachment, cell proliferation, osteogenic gene expression, bone regeneration, biomechanical stability, and bone-biomaterial contact were evaluated using apatite forming ability test, cell culture assays, and animal experiments. It was found that AcAl and AnH work through completely different routes. While AcAl improved the apatite forming ability of as-manufactured (AsM) specimens, it did not have any positive effect on cell attachment, cell proliferation, and osteogenic gene expression. In contrast, AnH did not improve the apatite forming ability of AsM specimens but showed significantly better cell attachment, cell proliferation, and expression of osteogenic markers. The performance of AlAcH in terms of apatite forming ability and cell response was in between both extremes of AnH and AsM. AcAl resulted in significantly larger volumes of newly formed bone within the pores of the scaffold as compared to AnH. Interestingly, larger volumes of regenerated bone did not translate into improved biomechanical stability as AnH exhibited significantly better biomechanical stability as compared to AcAl suggesting that the beneficial effects of cell-nanotopography modulations somehow surpassed the benefits of improved apatite forming ability. In conclusion, the applied surface treatments have considerable effects on apatite forming ability, cell attachment, cell proliferation, and bone ingrowth of the studied biomaterials. The relationship between these properties and the bone

Pyrophosphate-Inhibition of Apatite Formation Studied by In Situ X-Ray Diffraction

Directory of Open Access Journals (Sweden)

Casper Jon Steenberg Ibsen

2018-02-01

Full Text Available The pathways to crystals are still under debate, especially for materials relevant to biomineralization, such as calcium phosphate apatite known from bone and teeth. Pyrophosphate is widely used in biology to control apatite formation since it is a potent inhibitor of apatite crystallization. The impacts of pyrophosphate on apatite formation and crystallization kinetics are, however, not fully understood. Therefore, we studied apatite crystallization in water by synchrotron in situ X-ray diffraction. Crystallization was conducted from calcium chloride (0.2 M and sodium phosphate (0.12 M at pH 12 where hydrogen phosphate is the dominant phosphate species and at 60 °C to allow the synchrotron measurements to be conducted in a timely fashion. Following the formation of an initial amorphous phase, needle shaped crystals formed that had an octacalcium phosphate-like composition, but were too small to display the full 3D periodic structure of octacalcium phosphate. At later growth stages the crystals became apatitic, as revealed by changes in the lattice constant and calcium content. Pyrophosphate strongly inhibited nucleation of apatite and increased the onset of crystallization from minute to hour time scales. Pyrophosphate also reduced the rate of growth. Furthermore, when the pyrophosphate concentration exceeded ~1% of the calcium concentration, the resultant crystals had reduced size anisotropy suggesting that pyrophosphate interacts in a site-specific manner with the formation of apatite crystals.

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.

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

International Nuclear Information System (INIS)

Gallego, Daniel; Higuita, Natalia; Garcia, Felipe; Ferrell, Nicholas; Hansford, Derek J.

2008-01-01

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 2 atmosphere, allowing the formation of CaCO 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 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) 2 on C-, and CaCO 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

Dicty_cDB: CHA851 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available CH (Link to library) CHA851 (Link to dictyBase) - - - Contig-U16368-1 - (Link to Or...iginal site) CHA851F 614 - - - - - - Show CHA851 Library CH (Link to library) Clone ID CHA851 (Link to dicty...Base) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16368-1 Original site URL http://dictycdb.b...TCCXXXXXXXXXX sequence update 2002.10.25 Translated Amino Acid sequence VRDARPPHNLCRGFGCPEGSHCEVLEKHPVCVRNHVPPHPPPPPQICGSVNCGPGYICT...nly*skttgttttllnlcraiism*srwn dlysstkqlyqy*ipmlpis--- Frame C: VRDARPPHNLCRGFGCPEGSHCEVLEKHPVCVRNHVPPHPPPPPQICGSVNCGPGYICT

Injectable biphasic calcium phosphate cements as a potential bone substitute

NARCIS (Netherlands)

Sariibrahimoglu, K.; Wolke, J.G.C.; Leeuwenburgh, S.C.G.; Yubao, L.; Jansen, J.A.

2014-01-01

Apatitic calcium phosphate cements (CPCs) have been widely used as bone grafts due to their excellent osteoconductive properties, but the degradation properties are insufficient to stimulate bone healing in large bone defects. A novel approach to overcome the lack of degradability of apatitic CPC

Bone mineral as an electrical energy reservoir.

Science.gov (United States)

Nakamura, Miho; Hiratai, Rumi; Yamashita, Kimihiro

2012-05-01

Mechanical stress in bone induces an electrical potential generated by piezoelectricity arising from displacement of collagen fibrils. Where and for how long the potential is stored in bone; however, are still poorly understood. We investigated the electrical properties of collagen fibrils and apatite minerals and found that bone, when polarized electrically by applying an external voltage, depolarizes by two mechanisms. Plots of thermally stimulated depolarization current show two significant peaks: one at 100°C, attributed to collagen fibrils because decalcified bone exhibits depolarization peak at 100°C, and the other at 500°C, attributed to apatite minerals because calcined bone exhibits depolarization peak at 500°C and has activation energy similar to that for synthesized apatite. The crystallographic c-axis orientation of calcined bone depends on the direction in which the bone is cut, either transverse or longitudinal, and strongly affects the polarization efficacy. Copyright © 2012 Wiley Periodicals, Inc.

Effects of laser photherapy on bone defects grafted with mineral trioxide aggregate, bone morphogenetic proteins, and guided bone regeneration: a Raman spectroscopic study.

Science.gov (United States)

Pinheiro, Antonio L B; Aciole, Gilberth T S; Cangussú, Maria Cristina T; Pacheco, Marcos T T; Silveira, Landulfo

2010-12-15

We have used Raman analysis to assess bone healing on different models. Benefits on the isolated or combined use of mineral trioxide aggregate, bone morphogenetic proteins, guided bone regeneration and laser on bone repair have been reported, but not their combination. We studied peaks of hydroxyapatite and CH groups on defects grafted with MTA, treated or not with laser, BMPs, and GBR. Ninety rats were divided in 10 groups each, subdivided into three subgroups. Laser (λ850 nm) was applied at every other day for 2 weeks. Raman readings were taken at the surface of the defect. Statistical analysis (CHA) showed significant differences between all groups (p = 0.001) and between Group II and all other (p hydroxyapatite (CHA) that is indicative of greater calcification and resistance of the bone. We conclude that the association of the MTA with laser phototherapy (LPT) and/or not with GBR resulted in a better bone repair. The use of the MTA associated to IR LPT resulted in a more advanced and quality bone repair. Copyright © 2010 Wiley Periodicals, Inc.

A new technique for the assessment of the 3D spatial distribution of the calcium/phosphorus ratio in bone apatite.

Science.gov (United States)

Hadjipanteli, A; Kourkoumelis, N; Fromme, P; Olivo, A; Huang, J; Speller, R

2013-11-01

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.

In vitro biomimetic deposition of apatite on alkaline and heat treated ...

Indian Academy of Sciences (India)

WINTEC

materials of choice for most dental and orthopedic appli- .... treatment on the surface of the substrate and the structure of the titanium substrate, gel layer and bone-like apatite coatings obtained were analysed by thin film X-ray dif-.

Preparation and Characterization of Apatitic Biphasic Calcium Phosphate

International Nuclear Information System (INIS)

Thin Thin Nwe; Kyaw Naing; Khin Mar Tun; Nyunt Wynn

2005-09-01

The apatitic biphasic calcium phosphate (ABcp) consisting of hydroxyapatite (HA) and -tricalcium phosphate ( -Tcp) has been prepared by precipitation technique using slaked lime and orthophosphoric acid. The X-ray diffraction analysis of the product I (hydroxyapatite) revealed that ABcp was partially crystalline state. However, on heating at 800 C for 8 hrs, XRD pattern indicated a perfectly crystalline form of ABcp. This observation was supported by FT-IR measurement. The change in morphology regarding in the functional nature was infered by the shift in the FT-IR frequency. The optimization of the apatitic biphasic calcium phosphate was done by the variation of disodium hydrogen phosphate concentration, setting time, hardening time as well as compressive strength. The perpared cement may be used as an artificial substitution bone

Biomimetic nanocrystalline apatite coatings synthesized by Matrix Assisted Pulsed Laser Evaporation for medical applications

Energy Technology Data Exchange (ETDEWEB)

Visan, A. [National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, RO-77125, MG-36, Magurele-Ilfov (Romania); Grossin, D. [CIRIMAT – Carnot Institute, University of Toulouse, ENSIACET, 4 Allée Emile Monso, 31030 Toulouse Cedex 4 (France); Stefan, N.; Duta, L.; Miroiu, F.M. [National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, RO-77125, MG-36, Magurele-Ilfov (Romania); Stan, G.E. [National Institute of Materials Physics, RO-077125, Magurele-Ilfov (Romania); Sopronyi, M.; Luculescu, C. [National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, RO-77125, MG-36, Magurele-Ilfov (Romania); Freche, M.; Marsan, O.; Charvilat, C. [CIRIMAT – Carnot Institute, University of Toulouse, ENSIACET, 4 Allée Emile Monso, 31030 Toulouse Cedex 4 (France); Ciuca, S. [Politehnica University of Bucharest, Faculty of Materials Science and Engineering, Bucharest (Romania); Mihailescu, I.N., E-mail: ion.mihailescu@inflpr.ro [National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, RO-77125, MG-36, Magurele-Ilfov (Romania)

2014-02-15

Highlights: • We report the deposition by MAPLE of biomimetic apatite coatings on Ti substrates. • This is the first report of MAPLE deposition of hydrated biomimetic apatite films. • Biomimetic apatite powder was synthesized by double decomposition process. • Non-apatitic environments, of high surface reactivity, are preserved post-deposition. • We got the MAPLE complete transfer as thin film of a hydrated, delicate material. -- Abstract: We report the deposition by Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique of biomimetic nanocrystalline apatite coatings on titanium substrates, with potential application in tissue engineering. The targets were prepared from metastable, nanometric, poorly crystalline apatite powders, analogous to mineral bone, synthesized through a biomimetic approach by double decomposition process. For the deposition of thin films, a KrF* excimer laser source was used (λ = 248 nm, τ{sub FWHM} ≤ 25 ns). The analyses revealed the existence, in synthesized powders, of labile non-apatitic mineral ions, associated with the formation of a hydrated layer at the surface of the nanocrystals. The thin film analyses showed that the structural and chemical nature of the nanocrystalline apatite was prevalently preserved. The perpetuation of the non-apatitic environments was also observed. The study indicated that MAPLE is a suitable technique for the congruent transfer of a delicate material, such as the biomimetic hydrated nanohydroxyapatite.

Biomimetic nanocrystalline apatite coatings synthesized by Matrix Assisted Pulsed Laser Evaporation for medical applications

International Nuclear Information System (INIS)

Visan, A.; Grossin, D.; Stefan, N.; Duta, L.; Miroiu, F.M.; Stan, G.E.; Sopronyi, M.; Luculescu, C.; Freche, M.; Marsan, O.; Charvilat, C.; Ciuca, S.; Mihailescu, I.N.

2014-01-01

Highlights: • We report the deposition by MAPLE of biomimetic apatite coatings on Ti substrates. • This is the first report of MAPLE deposition of hydrated biomimetic apatite films. • Biomimetic apatite powder was synthesized by double decomposition process. • Non-apatitic environments, of high surface reactivity, are preserved post-deposition. • We got the MAPLE complete transfer as thin film of a hydrated, delicate material. -- Abstract: We report the deposition by Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique of biomimetic nanocrystalline apatite coatings on titanium substrates, with potential application in tissue engineering. The targets were prepared from metastable, nanometric, poorly crystalline apatite powders, analogous to mineral bone, synthesized through a biomimetic approach by double decomposition process. For the deposition of thin films, a KrF* excimer laser source was used (λ = 248 nm, τ FWHM ≤ 25 ns). The analyses revealed the existence, in synthesized powders, of labile non-apatitic mineral ions, associated with the formation of a hydrated layer at the surface of the nanocrystals. The thin film analyses showed that the structural and chemical nature of the nanocrystalline apatite was prevalently preserved. The perpetuation of the non-apatitic environments was also observed. The study indicated that MAPLE is a suitable technique for the congruent transfer of a delicate material, such as the biomimetic hydrated nanohydroxyapatite

[Apatite-forming ability of pure titanium implant after micro-arc oxidation treatment].

Science.gov (United States)

Tian, Zhihui; Zhang, Yu; Wang, Lichao; Nan, Kaihui

2013-10-01

To investigate the apatite forming ability of pure titanium implant after micro-arc oxidation treatment in simulated body fluid (SBF) and obtain implants with calcium phosphate (Ca-P) layers. The implants were immersed in (SBF) after micro-arc oxidation treatment for different time lengths, and their apatite forming ability and the morphology and constituents of the Ca-P layers formed on the sample surface were analyzed using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and energy dispersive electron probe. After immersion in SBF, large quantities of Ca-P layers were induced on the surface of the samples. The Ca-P layers were composed of octacalcium phosphate and carbonated hydroxyapatite, and the crystals showed a plate-like morphology with an oriented growth. The implants with micro-arc oxidation treatment show good apatite forming ability on the surface with rich calcium and phosphorus elements. The formed layers are composed of bone-like apatite including octacalcium phosphate and carbonated hydroxyapatite.

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

MoCha: Molecular Characterization of Unknown Pathways.

Science.gov (United States)

Lobo, Daniel; Hammelman, Jennifer; Levin, Michael

2016-04-01

Automated methods for the reverse-engineering of complex regulatory networks are paving the way for the inference of mechanistic comprehensive models directly from experimental data. These novel methods can infer not only the relations and parameters of the known molecules defined in their input datasets, but also unknown components and pathways identified as necessary by the automated algorithms. Identifying the molecular nature of these unknown components is a crucial step for making testable predictions and experimentally validating the models, yet no specific and efficient tools exist to aid in this process. To this end, we present here MoCha (Molecular Characterization), a tool optimized for the search of unknown proteins and their pathways from a given set of known interacting proteins. MoCha uses the comprehensive dataset of protein-protein interactions provided by the STRING database, which currently includes more than a billion interactions from over 2,000 organisms. MoCha is highly optimized, performing typical searches within seconds. We demonstrate the use of MoCha with the characterization of unknown components from reverse-engineered models from the literature. MoCha is useful for working on network models by hand or as a downstream step of a model inference engine workflow and represents a valuable and efficient tool for the characterization of unknown pathways using known data from thousands of organisms. MoCha and its source code are freely available online under the GPLv3 license.

Apatite mineralization in elasmobranch skeletons via a polyphosphate intermediate

Science.gov (United States)

Omelon, Sidney; Lacroix, Nicolas; Lildhar, Levannia; Variola, Fabio; Dean, Mason

2014-05-01

All vertebrate skeletons are stiffened with apatite, a calcium phosphate mineral. Control of apatite mineralization is essential to the growth and repair of the biology of these skeletons, ensuring that apatite is deposited in the correct tissue location at the desired time. The mechanism of this biochemical control remains debated, but must involve increasing the localized apatite saturation state. It was theorized in 1923 that alkaline phosphatase (ALP) activity provides this control mechanism by increasing the inorganic phosphate (Pi) concentration via dephosphorylation of phosphorylated molecules. The ALP substrate for biological apatite is not known. We propose that polyphosphates (polyPs) produced by mitochondria may be the substrate for biological apatite formation by ALP activity. PolyPs (PO3-)n, also known as condensed phosphates, represent a concentrated, bioavailable Pi-storage strategy. Mitochondria import Pi and synthesize phosphate polymers through an unknown biochemical mechanism. When chelated with calcium and/or other cations, the effective P-concentration of these neutrally charged, amorphous, polyP species can be very high (~ 0.5 M), without inducing phosphate mineral crystallization. This P-concentration in the low Pi-concentration biological environment offers a method of concentrating P well above an apatite supersaturation required for nucleation. Bone is the most studied mineralized skeletal tissue. However, locating and analyzing active mineralizing areas is challenging. We studied calcified cartilage skeletons of elasmobranch fishes (sharks, stingrays and relatives) to analyse the phosphate chemistry in this continually mineralizing skeleton. Although the majority of the elasmobranch skeleton is unmineralized cartilage, it is wrapped in an outer layer of mineralized tissue comprised of small tiles called tesserae. These calcified tesserae continually grow through the formation of new mineral on their borders. Co-localization of ALP and

Formation of apatite on hydrogenated amorphous silicon (a-Si:H) film deposited by plasma-enhanced chemical vapor deposition

International Nuclear Information System (INIS)

Liu Xuanyong; Chu, Paul K.; Ding Chuanxian

2007-01-01

Hydrogenated amorphous silicon films were fabricated on p-type, 100 mm diameter silicon wafers by plasma-enhanced chemical vapor deposition (PECVD) using silane and hydrogen. The structure and composition of the hydrogenated amorphous silicon films were investigated using micro-Raman spectroscopy and cross-sectional transmission electron microscopy (XTEM). The hydrogenated amorphous silicon films were subsequently soaked in simulated body fluids to evaluate apatite formation. Carbonate-containing hydroxyapatite (bone-like apatite) was formed on the surface suggesting good bone conductivity. The amorphous structure and presence of surface Si-H bonds are believed to induce apatite formation on the surface of the hydrogenated amorphous silicon film. A good understanding of the surface bioactivity of silicon-based materials and means to produce a bioactive surface is important to the development of silicon-based biosensors and micro-devices that are implanted inside humans

Formation of apatite on hydrogenated amorphous silicon (a-Si:H) film deposited by plasma-enhanced chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Liu Xuanyong [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China) and Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)]. E-mail: xyliu@mail.sic.ac.cn; Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)]. E-mail: paul.chu@cityu.edu.hk; Ding Chuanxian [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China)

2007-01-15

Hydrogenated amorphous silicon films were fabricated on p-type, 100 mm diameter <1 0 0> silicon wafers by plasma-enhanced chemical vapor deposition (PECVD) using silane and hydrogen. The structure and composition of the hydrogenated amorphous silicon films were investigated using micro-Raman spectroscopy and cross-sectional transmission electron microscopy (XTEM). The hydrogenated amorphous silicon films were subsequently soaked in simulated body fluids to evaluate apatite formation. Carbonate-containing hydroxyapatite (bone-like apatite) was formed on the surface suggesting good bone conductivity. The amorphous structure and presence of surface Si-H bonds are believed to induce apatite formation on the surface of the hydrogenated amorphous silicon film. A good understanding of the surface bioactivity of silicon-based materials and means to produce a bioactive surface is important to the development of silicon-based biosensors and micro-devices that are implanted inside humans.

Formation of Apatite Coatings on an Artificial Ligament Using a Plasma- and Precursor-Assisted Biomimetic Process

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Ayako Oyane

2013-09-01

Full Text Available A plasma- and precursor-assisted biomimetic process utilizing plasma and alternate dipping treatments was applied to a Leed-Keio artificial ligament to produce a thin coating of apatite in a supersaturated calcium phosphate solution. Following plasma surface modification, the specimen was alternately dipped in calcium and phosphate ion solutions three times (alternate dipping treatment to create a precoating containing amorphous calcium phosphate (ACP which is an apatite precursor. To grow an apatite layer on the ACP precoating, the ACP-precoated specimen was immersed for 24 h in a simulated body fluid with ion concentrations approximately equal to those in human blood plasma. The plasma surface modification was necessary to create an adequate apatite coating and to improve the coating adhesion depending on the plasma power density. The apatite coating prepared using the optimized conditions formed a thin-film that covered the entire surface of the artificial ligament. The resulting apatite-coated artificial ligament should exhibit improved osseointegration within the bone tunnel and possesses great potential for use in ligament reconstructions.

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.

UV photofunctionalization promotes nano-biomimetic apatite deposition on titanium

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Saita M

2016-01-01

in the valleys and at the inclines of micro-roughened structures without affecting the existing micro-configuration. Micro-roughened titanium and apatite-deposited titanium surfaces had similar roughness values. The attachment, spreading, settling, proliferation, and alkaline phosphate activity of bone marrow-derived osteoblasts were promoted on apatite-coated titanium with photofunctionalization.Conclusion: UV-photofunctionalization of titanium enabled faster deposition of nanoscale biomimetic apatite, resulting in the improved biological capability compared to the similarly prepared apatite-deposited titanium without photofunctionalization. Photofunctionalization-assisted biomimetic apatite deposition may be a novel method to effectively enhance micro-roughened titanium surfaces without altering their microscale morphology. Keywords: nanotechnology, dental and orthopedic implants, superhydrophilic, hydrocarbon, osseointegration 

From waste to high-value product: Jackfruit peel derived pectin/apatite bionanocomposites for bone healing applications.

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Govindaraj, Dharman; Rajan, Mariappan; Hatamleh, Ashraf A; Munusamy, Murugan A

2018-01-01

Public requirements encouraged by the current asset framework drive industry to expand its general effectiveness by enhancing existing procedures or finding new uses for waste. Thus, the aim of this study was the isolation, fabrication, and characterization of pectin derived from jackfruit (Artocarpus heterophyllus) peels and the generation of hybrid of pectin (P)/apatite (HA) (P/HA) bionanocomposites. In this process, the natural pectin polymer derived from the peel of jackfruits was used in different concentrations for the fabrication of HA bionanocomposites. Characterization of the isolated pectin and bionanocomposites samples was performed with 1 H NMR and 13 C NMR, FTIR, XRD, SEM-EDX, and HR-TEM. Cytocompatibility, ALP, fibroblast stem cells, anti-inflammatory and cell adhesion testing of the fabricated bionanocomposites was showed good biocompatibility. Our results signify that the fabricated bionanocomposites might be applicable as bone graft materials. Copyright © 2017 Elsevier B.V. All rights reserved.

Iodine immobilization in apatites

International Nuclear Information System (INIS)

Audubert, F.; Lartigue, J.E.

2000-01-01

In the context of a scientific program on long-lived radionuclide conditioning, a matrix for iodine 129 immobilization has been studied. A lead vanado-phosphate apatite was prepared from the melt of lead vanado-phosphate Pb 3 (VO 4 ) 1.6 (PO 4 ) 0.4 and lead iodide PbI 2 in stoichiometric proportions by calcination at 700 deg. C during 3 hours. Natural sintering of this apatite is not possible because the product decomposition occurs at 400 deg. C. Reactive sintering is the solution. The principle depends on the coating of lead iodide with lead vanado-phosphate. Lead vanado-phosphate coating is used as iodo-apatite reactant and as dense covering to confine iodine during synthesis. So the best condition to immobilize iodine during iodo-apatite synthesis is a reactive sintering at 700 deg. C under 25 MPa. We obtained an iodo-apatite surrounded with dense lead vanadate. Leaching behaviour of the matrix synthesized by solid-solid reaction is under progress in order to determine chemical durability, basic mechanisms of the iodo-apatite alteration and kinetic rate law. Iodo-apatite dissolution rates were pH and temperature dependent. We obtained a rate of 2.5 10 -3 g.m -2 .d -1 at 90 deg. C in initially de-ionised water. (authors)

Amorphous surface layer versus transient amorphous precursor phase in bone - A case study investigated by solid-state NMR spectroscopy.

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Von Euw, Stanislas; Ajili, Widad; Chan-Chang, Tsou-Hsi-Camille; Delices, Annette; Laurent, Guillaume; Babonneau, Florence; Nassif, Nadine; Azaïs, Thierry

2017-09-01

The presence of an amorphous surface layer that coats a crystalline core has been proposed for many biominerals, including bone mineral. In parallel, transient amorphous precursor phases have been proposed in various biomineralization processes, including bone biomineralization. Here we propose a methodology to investigate the origin of these amorphous environments taking the bone tissue as a key example. This study relies on the investigation of a bone tissue sample and its comparison with synthetic calcium phosphate samples, including a stoichiometric apatite, an amorphous calcium phosphate sample, and two different biomimetic apatites. To reveal if the amorphous environments in bone originate from an amorphous surface layer or a transient amorphous precursor phase, a combined solid-state nuclear magnetic resonance (NMR) experiment has been used. The latter consists of a double cross polarization 1 H→ 31 P→ 1 H pulse sequence followed by a 1 H magnetization exchange pulse sequence. The presence of an amorphous surface layer has been investigated through the study of the biomimetic apatites; while the presence of a transient amorphous precursor phase in the form of amorphous calcium phosphate particles has been mimicked with the help of a physical mixture of stoichiometric apatite and amorphous calcium phosphate. The NMR results show that the amorphous and the crystalline environments detected in our bone tissue sample belong to the same particle. The presence of an amorphous surface layer that coats the apatitic core of bone apatite particles has been unambiguously confirmed, and it is certain that this amorphous surface layer has strong implication on bone tissue biogenesis and regeneration. Questions still persist on the structural organization of bone and biomimetic apatites. The existing model proposes a core/shell structure, with an amorphous surface layer coating a crystalline bulk. The accuracy of this model is still debated because amorphous calcium

Biological Apatite Formed from Polyphosphate and Alkaline Phosphatase May Exchange Oxygen Isotopes from Water through Carbonate

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Omelon, S. J.; Stanley, S. Y.; Gorelikov, I.; Matsuura, N.

2011-12-01

The oxygen isotopic composition in bone mineral phosphate is known to reflect the local water composition, environmental humidity, and diet1. Once ingested, biochemical processes presumably equilibrate PO43- with "body water" by the many biochemical reactions involving PO43- 2. Blake et al. demonstrated that enzymatic release of PO43- from organophosphorus compounds, and microbial metabolism of dissolved orthophosphate, significantly exchange the oxygen in precipitated apatite within environmental water3,4, which otherwise does not exchange with water at low temperatures. One of the enzymes that can cleave phosphates from organic substrates is alkaline phosphastase5, the enzyme also associated with bone mineralization. The literature often states that the mineral in bone in hydroxylapatite, however the mineral in bone is carbonated apatite that also contains some fluoride6. Deprotonation of HPO32- occurs at pH 12, which is impossibly high for biological system, and the predominate carbonate species in solution at neutral pH is HCO3-. To produce an apatite mineral without a significant hydroxyl content, it is possible that apatite biomineralization occurs through a polyphosphate pathway, where the oxygen atom required to transform polyphosphate into individual phosphate ions is from carbonate: [PO3-]n + CO32- -> [PO3-]n-1 + PO43- + CO2. Alkaline phosphatase can depolymerise polyphosphate into orthophosphate5. If alkaline phosphatase cleaves an oxygen atom from a calcium-carbonate complex, then there is no requirement for removing a hydrogen atom from the HCO3- or HPO43- ions of body water to form bioapatite. A mix of 1 mL of 1 M calcium polyphosphate hydogel, or nano-particles of calcium polyphosphate, and amorphous calcium carbonate were reacted with alkaline phosphatase, and maintained at neutral to basic pH. After two weeks, carbonated apatite and other calcium phosphate minerals were identified by powder x-ray diffraction. Orthophosphate and unreacted

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.

Development of nanosized silver-substituted apatite for biomedical applications: A review.

Science.gov (United States)

Lim, Poon Nian; Chang, Lei; Thian, Eng San

2015-08-01

The favorable biocompatibility of hydroxyapatite (HA) makes it a popular bone graft material as well as a coating layer on metallic implant. To reduce implant-related infections, silver ions were either incorporated into the apatite during co-precipitation process (AgHA-CP) or underwent ion-exchange with the calcium ions in the apatite (AgHA-IE). However, the distribution of silver ions in AgHA-CP and AgHA-IE was different, thus affecting the antibacterial action. Several studies reported that nanosized AgHA-CP containing 0.5 wt.% of silver provided an optimal trade-off between antibacterial properties and cytotoxicity. Nevertheless, nanosized AgHA and AgHA nanocoatings could not function ideally due to the compromise in the bone differentiation of mesenchymal stem cells, as evidenced in the reduced alkaline phosphatase, type I collagen and osteocalcin. Preliminary studies showed that biological responses of nanosized AgHA and AgHA nanocoatings could be improved with the addition of silicon. This review will discuss on nanosized AgHA and AgHA nanocoatings. In many patients needing bone graft material, hydroxyapatite (HA) has proven to be a popular choice. Nonetheless, implant-related infections remain a major concern. Hence, effective preventive measures are needed. In this review article, the authors discussed the application of incorporating silver nanoparticles in HA and its use as bone graft biomaterials together with the addition of silica. Copyright © 2015 Elsevier Inc. All rights reserved.

Texture analyses of Sauropod dinosaur bones from Tendaguru

International Nuclear Information System (INIS)

Pyzalla, A.R.; Sander, P.M.; Hansen, A.; Ferreyro, R.; Yi, S.-B.; Stempniewicz, M.; Brokmeier, H.-G.

2006-01-01

The apatite texture of fossil Brachiosaurus brancai and Barosaurus africanus sauropod bones from the excavation site at Tendaguru, Tanzania, was characterized by neutron diffraction pole figures. The results obtained reveal predominantly -fibre textures of the apatite; the fibre direction coincides with the longitudinal direction of the long bones of the skeletons. Neutron pole figures further indicate that other texture types may also be present. Texture strength is similar to dinosaur tendons and contemporary turkey tendon studied by others. Variations of texture strength across the bone wall cross-sections are not significantly large

Apatite Formation and Biocompatibility of a Low Young's Modulus Ti-Nb-Sn Alloy Treated with Anodic Oxidation and Hot Water.

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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.

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

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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.

Sr-substituted bone cements direct mesenchymal stem cells, osteoblasts and osteoclasts fate.

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Monica Montesi

Full Text Available Strontium-substituted apatitic bone cements enriched with sodium alginate were developed as a potential modulator of bone cells fate. The biological impact of the bone cement were investigated in vitro through the study of the effect of the nanostructured apatitic composition and the doping of strontium on mesenchymal stem cells, pre-osteoblasts and osteoclasts behaviours. Up to 14 days of culture the bone cells viability, proliferation, morphology and gene expression profiles were evaluated. The results showed that different concentrations of strontium were able to evoke a cell-specific response, in fact an inductive effect on mesenchymal stem cells differentiation and pre-osteoblasts proliferation and an inhibitory effect on osteoclasts activity were observed. Moreover, the apatitic structure of the cements provided a biomimetic environment suitable for bone cells growth. Therefore, the combination of biological features of this bone cement makes it as promising biomaterials for tissue regeneration.

Apatite Formation and Biocompatibility of a Low Young’s Modulus Ti-Nb-Sn Alloy Treated with Anodic Oxidation and Hot Water

Science.gov (United States)

Tanaka, Hidetatsu; Mori, Yu; Noro, Atsushi; Kogure, Atsushi; Kamimura, Masayuki; Yamada, Norikazu; Hanada, Shuji; Masahashi, Naoya; Itoi, Eiji

2016-01-01

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. PMID:26914329

Texture analyses of Sauropod dinosaur bones from Tendaguru

Energy Technology Data Exchange (ETDEWEB)

Pyzalla, A.R. [TU Wien, Institute of Material Science and Technology, Karlsplatz 13-308, A-1040 Vienna (Austria) and MPI fuer Eisenforschung GmbH, Max-Planck-Str. 1, D-40237 Duesseldorf (Germany)]. E-mail: pyzalla@mpie.de; Sander, P.M. [University of Bonn, Institute of Palaeontology, Nusseallee, D-53115 Bonn (Germany); Hansen, A. [TU Clausthal, Institute of Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processingnd GKSS Research Centre Geesthacht GmbH, Geesthacht, Max-Planck-Str.1, D-21502 Geesthacht (Germany); Ferreyro, R. [TU Wien, Institute of Material Science and Technology, Karlsplatz 13-308, A-1040 Vienna (Austria); Yi, S.-B. [TU Clausthal, Institute of Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processingnd GKSS Research Centre Geesthacht GmbH, Geesthacht, Max-Planck-Str.1, D-21502 Geesthacht (Germany); MPI fuer Eisenforschung GmbH, Max-Planck-Str. 1, D-40237 Duesseldorf (Germany); Stempniewicz, M. [TU Wien, Institute of Material Science and Technology, Karlsplatz 13-308, A-1040 Vienna (Austria); Brokmeier, H.-G. [TU Clausthal, Institute of Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processingnd GKSS Research Centre Geesthacht GmbH, Geesthacht, Max-Planck-Str.1, D-21502 Geesthacht (Germany)

2006-11-10

The apatite texture of fossil Brachiosaurus brancai and Barosaurus africanus sauropod bones from the excavation site at Tendaguru, Tanzania, was characterized by neutron diffraction pole figures. The results obtained reveal predominantly <0 0 0 1>-fibre textures of the apatite; the fibre direction coincides with the longitudinal direction of the long bones of the skeletons. Neutron pole figures further indicate that other texture types may also be present. Texture strength is similar to dinosaur tendons and contemporary turkey tendon studied by others. Variations of texture strength across the bone wall cross-sections are not significantly large.

Implicit Reasons for Disclosure of the Use of Complementary Health Approaches (CHA): a Consumer Commitment Perspective.

Science.gov (United States)

Sirois, Fuschia M; Riess, Helene; Upchurch, Dawn M

2017-10-01

Disclosure of the use of complementary health approaches (CHA) is an important yet understudied health behavior with important implications for patient care. Yet research into disclosure of CHA has been atheoretical and neglected the role of health beliefs. Using a consumer commitment model of CHA use as a guiding conceptual framework, the current study tests the hypotheses that perceived positive CHA outcomes (utilitarian values) and positive CHA beliefs (symbolic values) are associated with disclosure of CHA to conventional care providers in a nationally representative US sample. From a sample of 33,594 with CHA use information from the 2012 National Health Interview Survey (NHIS), a subsample of 7348 who used CHA within the past 12 months was analyzed. The 2012 NHIS is a cross-sectional survey of the non-institutionalized US adult population, which includes the most recent nationally representative CHA use data. The 63.2% who disclosed CHA use were older, were less educated, and had visited a health care provider in the past year. Weighted logistic regression analyses controlling for demographic variables revealed that those who disclosed were more likely to report experiencing positive psychological (improved coping and well-being) and physical outcomes (better sleep, improved health) from CHA and hold positive CHA-related beliefs. CHA users who perceive physical and psychological benefits from CHA use and who hold positive attitudes towards CHA are more likely to disclose their CHA use. Findings support the relevance of a consumer commitment perspective for understanding CHA disclosure and suggest CHA disclosure as an important proactive health behavior that warrants further attention.

Coherent scattering and matrix correction in bone-lead measurements

International Nuclear Information System (INIS)

Todd, A.C.

2000-01-01

The technique of K-shell x-ray fluorescence of lead in bone has been used in many studies of the health effects of lead. This paper addresses one aspect of the technique, namely the coherent conversion factor (CCF) which converts between the matrix of the calibration standards and those of human bone. The CCF is conventionally considered a constant but is a function of scattering angle, energy and the elemental composition of the matrices. The aims of this study were to quantify the effect on the CCF of several assumptions which may not have been tested adequately and to compare the CCFs for plaster of Paris (the present matrix of calibration standards) and a synthetic apatite matrix. The CCF was calculated, using relativistic form factors, for published compositions of bone, both assumed and assessed compositions of plaster, and the synthetic apatite. The main findings of the study were, first, that impurities in plaster, lead in the plaster or bone matrices, coherent scatter from non-bone tissues and the individual subject's measurement geometry are all minor or negligible effects; and, second, that the synthetic apatite matrix is more representative of bone mineral than is plaster of Paris. (author)

Dicty_cDB: CHA362 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available CH (Link to library) CHA362 (Link to dictyBase) - - - Contig-U15579-1 | Contig-U156... library) Clone ID CHA362 (Link to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U155...79-1 | Contig-U15687-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/C...XACNAVDTCITNDLCFPRECNPRGNPPCLINPINCTSTDPCIFSYCENGVCI PTYICTPTPSVTPTVTPTVTPTVTPTVT...GNPPCLINPINCTSTDPCIFSYCENGVCI PTYICTPTPSVTPTVTPTVTPTVTPTVTPTVTPTVTPTPTTTPTPSPTTVP

Paradiaphyseal calcific tendinitis with cortical bone erosion.

Science.gov (United States)

Fritz, P; Bardin, T; Laredo, J D; Ziza, J M; D'Anglejan, G; Lansaman, J; Bucki, B; Forest, M; Kuntz, D

1994-05-01

To determine the clinical, radiologic, and histologic features of calcific tendinitis with cortical bone erosion. The records of 6 patients with paradiaphyseal calcific tendinitis and adjacent bone cortex erosion were reviewed. Calcific tendinitis involved the linea aspera in 4 patients, the bicipital groove in 1 patient, and the deltoid insertion in another. Calcium deposits were associated with cortical bone erosions, revealed on plain radiographs in 4 patients and computed tomography scans in 2. Bone scans were performed in 2 patients and showed local hyperfixation of the isotope. In 4 patients, suspicion of a neoplasm led to a biopsy. Calcium deposits appeared to be surrounded by a foreign body reaction with numerous giant cells. Apatite crystals were identified by transmission electron microscopy and elemental analysis in 1 surgical sample. Paradiaphyseal calcific tendinitis with cortical bone erosion is an uncommon presentation of apatite deposition disease.

Diamond as a scaffold for bone growth.

Science.gov (United States)

Fox, Kate; Palamara, Joseph; Judge, Roy; Greentree, Andrew D

2013-04-01

Diamond is an attractive material for biomedical implants. In this work, we investigate its capacity as a bone scaffold. It is well established that the bioactivity of a material can be evaluated by examining its capacity to form apatite-like calcium phosphate phases on its surface when exposed to simulated body fluid. Accordingly, polycrystalline diamond (PCD) and ultrananocrystalline diamond (UNCD) deposited by microwave plasma chemical vapour deposition were exposed to simulated body fluid and assessed for apatite growth when compared to the bulk silicon. Scanning electron microscopy and X-ray photoelectron spectroscopy showed that both UNCD and PCD are capable of acting as a bone scaffold. The composition of deposited apatite suggests that UNCD and PCD are suitable for in vivo implantation with UNCD possible favoured in applications where rapid osseointegration is essential.

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.

Correlation between CHA2DS2-VASc Score and Glaucoma Treatment and Prognosis.

Science.gov (United States)

Pikkel, Yoav Y; Krebs, Daniel; Igal, Vadim; Sharabi-Nov, Adi; Epstein, Irena; Pikkel, Joseph

2018-01-01

To find if CHA 2 DS 2 -VASc scale can accurately predict the treatment, prognosis, and outcome for primary open-angle glaucoma (POAG). A survey of 250,000 patient years was taken, using the records of the Ophthalmology Department at Ziv Medical Center. Data was collected regarding the retinal nerve fiber layer (RNFL), visual field (VF), line of treatment (LOT) of glaucoma, and all the data needed to accurately calculate CHA 2 DS 2 -VASc score for each patient. Sixty-seven patients were included in the statistical analysis. The mean age was 72.5 years. The mean CHA 2 DS 2 -VASc score was 3.27 + -1.7. Positive Pearson's correlation coefficients were found for LOT and CHA 2 DS 2 -VASc score, 0.35, and for RNFL grade and CHA2DS2-VASc score, 0.37. The correlation was negative for RNFL width and CHA2DS2-VASc score, -0.35. CHA 2 DS 2 -VASc score was shown to be correlated with glaucoma. This correlation was manifested positively by the LOT needed to stop glaucoma progression, with higher CHA 2 DS 2 -VASc scores correlated with more aggressive treatment. Since glaucoma is a disease with a progressing nature, it is important to treat patients aggressively on one hand, while offering the most benign treatment as possible on the other hand. Modification of the CHA 2 DS 2 -VASc score could achieve an even higher correlation.

Influences of doping mesoporous magnesium silicate on water absorption, drug release, degradability, apatite-mineralization and primary cells responses to calcium sulfate based bone cements

International Nuclear Information System (INIS)

Gu, Zhengrong; Wang, Sicheng; Weng, Weizong; Chen, Xiao; Cao, Liehu; Wei, Jie; Shin, Jung-Woog; Su, Jiacan

2017-01-01

In this study, composite cements containing mesoporous magnesium silicate (m-MS) and calcium sulfate (CS) were fabricated. The results revealed that the setting time of the m-MS/CS composite cements (m-MSC) slightly prolonged with the increase of m-MS content while the compressive strength suffered a little loss. The doping of m-MS improved the water absorption, drug release (vancomycin) and degradability of the m-MSC in Tris-HCl solution (pH = 7.4). In addition, addition of m-MS facilitated the apatite-mineralization of m-MSC in simulated body fluid (SBF), indicating good bioactivity. For cell cultural experiments, the results revealed that the m-MSC promoted the cells adhesion and proliferation, and improved the alkaline phosphatase (ALP) activity of MC3T3-E1 cells, revealing good cytocompatibility. It could be suggested that the m-MSC might be promising cements biomaterials for bone tissue regeneration. - Highlights: • The mesoporous magnesium silicate and calcium sulfate composite was fabricated. • The composite possessed good water absorption and drug release of vancomycin. • The bioactive composite could enhance the in vivo apatite formation in SBF. • The composite promoted cell adhesion, proliferation and osteogenic differentiation.

Influences of doping mesoporous magnesium silicate on water absorption, drug release, degradability, apatite-mineralization and primary cells responses to calcium sulfate based bone cements

Energy Technology Data Exchange (ETDEWEB)

Gu, Zhengrong [Department of Trauma Orthopaedics, Changhai Hospital, Second Military Medical University, Shanghai 200433 (China); The Department of Orthopaedics, Jing' an District Centre Hospital of Shanghai (Huashan Hospital Fudan University Jing' An Branch), 200040 (China); Wang, Sicheng [Department of Trauma Orthopaedics, Changhai Hospital, Second Military Medical University, Shanghai 200433 (China); Department of Orthopaedics, Zhongye Hospital, Shanghai 200941 (China); Weng, Weizong; Chen, Xiao; Cao, Liehu [Department of Trauma Orthopaedics, Changhai Hospital, Second Military Medical University, Shanghai 200433 (China); Wei, Jie [Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Shin, Jung-Woog [Department of Biomedical Engineering, Inje University, Gimhae, 621749 (Korea, Republic of); Su, Jiacan, E-mail: jiacansu@sina.com [Department of Trauma Orthopaedics, Changhai Hospital, Second Military Medical University, Shanghai 200433 (China)

2017-06-01

In this study, composite cements containing mesoporous magnesium silicate (m-MS) and calcium sulfate (CS) were fabricated. The results revealed that the setting time of the m-MS/CS composite cements (m-MSC) slightly prolonged with the increase of m-MS content while the compressive strength suffered a little loss. The doping of m-MS improved the water absorption, drug release (vancomycin) and degradability of the m-MSC in Tris-HCl solution (pH = 7.4). In addition, addition of m-MS facilitated the apatite-mineralization of m-MSC in simulated body fluid (SBF), indicating good bioactivity. For cell cultural experiments, the results revealed that the m-MSC promoted the cells adhesion and proliferation, and improved the alkaline phosphatase (ALP) activity of MC3T3-E1 cells, revealing good cytocompatibility. It could be suggested that the m-MSC might be promising cements biomaterials for bone tissue regeneration. - Highlights: • The mesoporous magnesium silicate and calcium sulfate composite was fabricated. • The composite possessed good water absorption and drug release of vancomycin. • The bioactive composite could enhance the in vivo apatite formation in SBF. • The composite promoted cell adhesion, proliferation and osteogenic differentiation.

Impact of Surface Potential on Apatite Formation in Ti Alloys Subjected to Acid and Heat Treatments.

Science.gov (United States)

Yamaguchi, Seiji; Hashimoto, Hideki; Nakai, Ryusuke; Takadama, Hiroaki

2017-09-24

Titanium metal (Ti) and its alloys are widely used in orthopedic and dental fields. We have previously shown that acid and heat treatment was effective to introduce bone bonding, osteoconduction and osteoinduction on pure Ti. In the present study, acid and heat treatment with or without initial NaOH treatment was performed on typical Ti-based alloys used in orthopedic and dental fields. Dynamic movements of alloying elements were developed, which depended on the kind of treatment and type of alloy. It was found that the simple acid and heat treatment enriched/remained the alloying elements on Ti-6Al-4V, Ti-15Mo-5Zr-3Al and Ti-15Zr-4Nb-4Ta, resulting in neutral surface charges. Thus, the treated alloys did not form apatite in a simulated body fluid (SBF) within 3 days. In contrast, when the alloys were subjected to a NaOH treatment prior to an acid and heat treatment, alloying elements were selectively removed from the alloy surfaces. As a result, the treated alloys became positively charged, and formed apatite in SBF within 3 days. Thus, the treated alloys would be useful in orthopedic and dental fields since they form apatite even in a living body and bond to bone.

VizieR Online Data Catalog: ChaMP X-ray point source catalog (Kim+, 2007)

Science.gov (United States)

Kim, M.; Kim, D.-W.; Wilkes, B. J.; Green, P. J.; Kim, E.; Anderson, C. S.; Barkhouse, W. A.; Evans, N. R.; Ivezic, Z.; Karovska, M.; Kashyap, V. L.; Lee, M. G.; Maksym, P.; Mossman, A. E.; Silverman, J. D.; Tananbaum, H. D.

2009-01-01

We present the Chandra Multiwavelength Project (ChaMP) X-ray point source catalog with ~6800 X-ray sources detected in 149 Chandra observations covering ~10deg2. The full ChaMP catalog sample is 7 times larger than the initial published ChaMP catalog. The exposure time of the fields in our sample ranges from 0.9 to 124ks, corresponding to a deepest X-ray flux limit of f0.5-8.0=9x10-16ergs/cm2/s. The ChaMP X-ray data have been uniformly reduced and analyzed with ChaMP-specific pipelines and then carefully validated by visual inspection. The ChaMP catalog includes X-ray photometric data in eight different energy bands as well as X-ray spectral hardness ratios and colors. To best utilize the ChaMP catalog, we also present the source reliability, detection probability, and positional uncertainty. (10 data files).

Development of multisubstituted hydroxyapatite nanopowders as biomedical materials for bone tissue engineering applications.

Science.gov (United States)

Baba Ismail, Yanny M; Wimpenny, Ian; Bretcanu, Oana; Dalgarno, Kenneth; El Haj, Alicia J

2017-06-01

Ionic substitutions have been proposed as a tool to control the functional behavior of synthetic hydroxyapatite (HA), particularly for Bone Tissue Engineering applications. The effect of simultaneous substitution of different levels of carbonate (CO 3 ) and silicon (Si) ions in the HA lattice was investigated. Furthermore, human bone marrow-derived mesenchymal stem cells (hMSCs) were cultured on multi-substituted HA (SiCHA) to determine if biomimetic chemical compositions were osteoconductive. Of the four different compositions investigates, SiCHA-1 (0.58 wt % Si) and SiCHA-2 (0.45 wt % Si) showed missing bands for CO 3 and Si using FTIR analysis, indicating competition for occupation of the phosphate site in the HA lattice; 500°C was considered the most favorable calcination temperature as: (i) the powders produced possessed a similar amount of CO 3 (2-8 wt %) and Si (<1.0 wt %) as present in native bone; and (ii) there was a minimal loss of CO 3 and Si from the HA structure to the surroundings during calcination. Higher Si content in SiCHA-1 led to lower cell viability and at most hindered proliferation, but no toxicity effect occurred. While, lower Si content in SiCHA-2 showed the highest ALP/DNA ratio after 21 days culture with hMSCs, indicating that the powder may stimulate osteogenic behavior to a greater extent than other powders. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1775-1785, 2017. © 2017 Wiley Periodicals, Inc.

Assessment of copper removal from highway stormwater runoff using Apatite II(TM) and compost : laboratory and field testing.

Science.gov (United States)

2015-03-01

-Stormwater runoff introduces heavy metals to surface waters that are harmful to aquatic organisms, : including endangered salmon. This work evaluates Apatite II, a biogenic fish bone based adsorbent, for removing metal : from stormwater. The meta...

Finding the Patient's Voice Using Big Data: Analysis of Users' Health-Related Concerns in the ChaCha Question-and-Answer Service (2009-2012).

Science.gov (United States)

Priest, Chad; Knopf, Amelia; Groves, Doyle; Carpenter, Janet S; Furrey, Christopher; Krishnan, Anand; Miller, Wendy R; Otte, Julie L; Palakal, Mathew; Wiehe, Sarah; Wilson, Jeffrey

2016-03-09

The development of effective health care and public health interventions requires a comprehensive understanding of the perceptions, concerns, and stated needs of health care consumers and the public at large. Big datasets from social media and question-and-answer services provide insight into the public's health concerns and priorities without the financial, temporal, and spatial encumbrances of more traditional community-engagement methods and may prove a useful starting point for public-engagement health research (infodemiology). The objective of our study was to describe user characteristics and health-related queries of the ChaCha question-and-answer platform, and discuss how these data may be used to better understand the perceptions, concerns, and stated needs of health care consumers and the public at large. We conducted a retrospective automated textual analysis of anonymous user-generated queries submitted to ChaCha between January 2009 and November 2012. A total of 2.004 billion queries were read, of which 3.50% (70,083,796/2,004,243,249) were missing 1 or more data fields, leaving 1.934 billion complete lines of data for these analyses. Males and females submitted roughly equal numbers of health queries, but content differed by sex. Questions from females predominantly focused on pregnancy, menstruation, and vaginal health. Questions from males predominantly focused on body image, drug use, and sexuality. Adolescents aged 12-19 years submitted more queries than any other age group. Their queries were largely centered on sexual and reproductive health, and pregnancy in particular. The private nature of the ChaCha service provided a perfect environment for maximum frankness among users, especially among adolescents posing sensitive health questions. Adolescents' sexual health queries reveal knowledge gaps with serious, lifelong consequences. The nature of questions to the service provides opportunities for rapid understanding of health concerns and may

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)

Sader, Marcia S.; Martins, Virginia C.A.; Gomez, Santiago; LeGeros, Racquel Z.; Soares, Gloria A.

2013-01-01

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

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.

The solution structure of ChaB, a putative membrane ion antiporter regulator from Escherichia coli

Directory of Open Access Journals (Sweden)

Iannuzzi Pietro

2004-08-01

Full Text Available Abstract Background ChaB is a putative regulator of ChaA, a Na+/H+ antiporter that also has Ca+/H+ activity in E. coli. ChaB contains a conserved 60-residue region of unknown function found in other bacteria, archaeabacteria and a series of baculoviral proteins. As part of a structural genomics project, the structure of ChaB was elucidated by NMR spectroscopy. Results The structure of ChaB is composed of 3 α-helices and a small sheet that pack tightly to form a fold that is found in the cyclin-box family of proteins. Conclusion ChaB is distinguished from its putative DNA binding sequence homologues by a highly charged flexible loop region that has weak affinity to Mg2+ and Ca2+ divalent metal ions.

Assessing screening criteria for the radiocarbon dating of bone mineral

Energy Technology Data Exchange (ETDEWEB)

Fernandes, Ricardo, E-mail: ldv1452@gmail.com [Leibniz Labor for Isotopic and Radiometric Dating, Max-Eyth-Str. 11-13, 24118 Kiel (Germany); Graduate School Human Development in Landscapes, Christian Albrecht University, Kiel (Germany); Huels, Matthias [Leibniz Labor for Isotopic and Radiometric Dating, Max-Eyth-Str. 11-13, 24118 Kiel (Germany); Nadeau, Marie-Josee; Grootes, Pieter M. [Leibniz Labor for Isotopic and Radiometric Dating, Max-Eyth-Str. 11-13, 24118 Kiel (Germany); Graduate School Human Development in Landscapes, Christian Albrecht University, Kiel (Germany); Garbe-Schoenberg, C.-Dieter [Institute of Geosciences, Marine Climate Research and ICPMS Lab, Kiel University, Ludewig-Meyn-Str. 10, D-24118 Kiel (Germany); Graduate School Human Development in Landscapes, Christian Albrecht University, Kiel (Germany); Hollund, Hege I. [Institute for Geo- and Bioarchaeology, The VU University, De Boelelaan 1085, 1081 HV Amsterdam (Netherlands); Lotnyk, Andriy [Faculty of Engineering, Institute for Material Science, Synthesis and Real Structure, Kiel University, Kaiserstr. 2, D-24143 Kiel (Germany); Leibniz Institute of Surface Modification (IOM), Permoserstr. 15, D-04318 Leipzig (Germany); Kienle, Lorenz [Faculty of Engineering, Institute for Material Science, Synthesis and Real Structure, Kiel University, Kaiserstr. 2, D-24143 Kiel (Germany); Graduate School Human Development in Landscapes, Christian Albrecht University, Kiel (Germany)

2013-01-15

Radiocarbon dating of bone mineral (carbonate in the apatite lattice) has been the target of sporadic research for the last 40 years. Results obtained by different decontamination protocols have, however, failed to provide a consistent agreement with reference ages. In particular, quality criteria to assess bone mineral radiocarbon dating reliability are still lacking. Systematic research was undertaken to identify optimal preservation criteria for bone mineral in archeological bones. Six human long bones, originating from a single site, were radiocarbon-dated both for collagen and apatite, with the level of agreement between the dates providing an indication of exogenous carbon contamination. Several techniques (Histology, FTIR, TEM, LA-ICP-MS) were employed to determine the preservation status of each sample. Research results highlight the importance of a micro-scale approach in establishing bone preservation, in particular the use of trace element concentration profiles demonstrated its potential use as a viable sample selection criterion for bone carbonate radiocarbon dating.

Abnormal arrangement of a collagen/apatite extracellular matrix orthogonal to osteoblast alignment is constructed by a nanoscale periodic surface structure.

Science.gov (United States)

Matsugaki, Aira; Aramoto, Gento; Ninomiya, Takafumi; Sawada, Hiroshi; Hata, Satoshi; Nakano, Takayoshi

2015-01-01

Morphological and directional alteration of cells is essential for structurally appropriate construction of tissues and organs. In particular, osteoblast alignment is crucial for the realization of anisotropic bone tissue microstructure. In this article, the orientation of a collagen/apatite extracellular matrix (ECM) was established by controlling osteoblast alignment using a surface geometry with nanometer-sized periodicity induced by laser ablation. Laser irradiation induced self-organized periodic structures (laser-induced periodic surface structures; LIPSS) with a spatial period equal to the wavelength of the incident laser on the surface of biomedical alloys of Ti-6Al-4V and Co-Cr-Mo. Osteoblast orientation was successfully induced parallel to the grating structure. Notably, both the fibrous orientation of the secreted collagen matrix and the c-axis of the produced apatite crystals were orientated orthogonal to the cell direction. To the best of our knowledge, this is the first report demonstrating that bone tissue anisotropy is controllable, including the characteristic organization of a collagen/apatite composite orthogonal to the osteoblast orientation, by controlling the cell alignment using periodic surface geometry. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

Apatite formation on organic polymers by biomimetic process using Na2O-SiO2 glasses as nucleating agent

Energy Technology Data Exchange (ETDEWEB)

Tanahashi, M; Yao, t; Kokubo, T [Kyoto University, Kyoto (Japan). Faculty of Engineering; Minoda, M; Miyamoto, T [Kyoto University, Kyoto (Japan). Institute for Chemical Research; Nakamura, T [Kyoto University, Kyoto (Japan). Research Center for Biomedical Engineering; Yamamuro, T [Kyoto University, Kyoto (Japan). Faculty of Medicine

1994-09-01

In this investigation, CaO-SiO2-based glass, which was previously used as the nucleating agent, was replaced by Na2O-SiO2 glasses, SiO2 glass, and SiO2 gel. The induction period for the apatite nucleation on various organic polymer substrates and the adhesive strength of the apatite layer to the substrates were examined. It was considered that the short induction period for the glasses with high Na2O contents was attributed to high dissolution rates of sodium and silicate ions from them. It was also considered that highly polar carboxyl or sulfinyl groups were formed on the polymer surfaces by the hydrolysis of their ester, amide or sulfonyl group in simulated body fluid with its pH increased by the Na{sup +} dissolution from the glass, and that these polar groups formed a strong bond with the apatite. It is suggested that thus formed apatite-organic polymer composites are useful as the bone-repairing as well as soft tissue-repairing materials. 11 refs., 13 figs., 3 tabs.

HERSCHEL OBSERVATIONS OF THE T CHA TRANSITION DISK: CONSTRAINING THE OUTER DISK PROPERTIES

International Nuclear Information System (INIS)

Cieza, Lucas A.; Olofsson, Johan; Henning, Thomas; Harvey, Paul M.; Evans II, Neal J.; Pinte, Christophe; Augereau, Jean-Charles; Ménard, Francois; Merín, Bruno; Najita, Joan

2011-01-01

T Cha is a nearby (d ∼ 100 pc) transition disk known to have an optically thin gap separating optically thick inner and outer disk components. Huélamo et al. recently reported the presence of a low-mass object candidate within the gap of the T Cha disk, giving credence to the suspected planetary origin of this gap. Here we present the Herschel photometry (70, 160, 250, 350, and 500 μm) of T Cha from the 'Dust, Ice, and Gas in Time' Key Program, which bridges the wavelength range between existing Spitzer and millimeter data and provide important constraints on the outer disk properties of this extraordinary system. We model the entire optical to millimeter wavelength spectral energy distribution (SED) of T Cha (19 data points between 0.36 and 3300 μm without any major gaps in wavelength coverage). T Cha shows a steep spectral slope in the far-IR, which we find clearly favors models with outer disks containing little or no dust beyond ∼40 AU. The full SED can be modeled equally well with either an outer disk that is very compact (only a few AU wide) or a much larger one that has a very steep surface density profile. That is, T Cha's outer disk seems to be either very small or very tenuous. Both scenarios suggest a highly unusual outer disk and have important but different implications for the nature of T Cha. Spatially resolved images are needed to distinguish between the two scenarios.

HERSCHEL OBSERVATIONS OF THE T CHA TRANSITION DISK: CONSTRAINING THE OUTER DISK PROPERTIES

Energy Technology Data Exchange (ETDEWEB)

Cieza, Lucas A. [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Olofsson, Johan; Henning, Thomas [Max Planck Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg (Germany); Harvey, Paul M.; Evans II, Neal J. [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Pinte, Christophe; Augereau, Jean-Charles; Menard, Francois [UJF-Grenoble 1/CNRS-INSU, Institut de Planetologie et d' Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble, F-38041 (France); Merin, Bruno [Herschel Science Centre, European Space Agency (ESAC), P.O. Box 78, 28691 Villanueva de la Canada, Madrid (Spain); Najita, Joan, E-mail: lcieza@ifa.hawaii.edu [National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 86719 (United States)

2011-11-10

T Cha is a nearby (d {approx} 100 pc) transition disk known to have an optically thin gap separating optically thick inner and outer disk components. Huelamo et al. recently reported the presence of a low-mass object candidate within the gap of the T Cha disk, giving credence to the suspected planetary origin of this gap. Here we present the Herschel photometry (70, 160, 250, 350, and 500 {mu}m) of T Cha from the 'Dust, Ice, and Gas in Time' Key Program, which bridges the wavelength range between existing Spitzer and millimeter data and provide important constraints on the outer disk properties of this extraordinary system. We model the entire optical to millimeter wavelength spectral energy distribution (SED) of T Cha (19 data points between 0.36 and 3300 {mu}m without any major gaps in wavelength coverage). T Cha shows a steep spectral slope in the far-IR, which we find clearly favors models with outer disks containing little or no dust beyond {approx}40 AU. The full SED can be modeled equally well with either an outer disk that is very compact (only a few AU wide) or a much larger one that has a very steep surface density profile. That is, T Cha's outer disk seems to be either very small or very tenuous. Both scenarios suggest a highly unusual outer disk and have important but different implications for the nature of T Cha. Spatially resolved images are needed to distinguish between the two scenarios.

Fabrication of mineralized electrospun PLGA and PLGA/gelatin nanofibers and their potential in bone tissue engineering

International Nuclear Information System (INIS)

Meng, Z.X.; Li, H.F.; Sun, Z.Z.; Zheng, W.; Zheng, Y.F.

2013-01-01

Surface mineralization is an effective method to produce calcium phosphate apatite coating on the surface of bone tissue scaffold which could create an osteophilic environment similar to the natural extracellular matrix for bone cells. In this study, we prepared mineralized poly(D,L-lactide-co-glycolide) (PLGA) and PLGA/gelatin electrospun nanofibers via depositing calcium phosphate apatite coating on the surface of these nanofibers to fabricate bone tissue engineering scaffolds by concentrated simulated body fluid method, supersaturated calcification solution method and alternate soaking method. The apatite products were characterized by the scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FT-IR), and X-ray diffractometry (XRD) methods. A large amount of calcium phosphate apatite composed of dicalcium phosphate dihydrate (DCPD), hydroxyapatite (HA) and octacalcium phosphate (OCP) was deposited on the surface of resulting nanofibers in short times via three mineralizing methods. A larger amount of calcium phosphate was deposited on the surface of PLGA/gelatin nanofibers rather than PLGA nanofibers because gelatin acted as nucleation center for the formation of calcium phosphate. The cell culture experiments revealed that the difference of morphology and components of calcium phosphate apatite did not show much influence on the cell adhesion, proliferation and activity. - Highlights: ► Ca–P phases were coated on PLGA/gelatin electrospun nanofiber membranes within 3 h. ► Ca–P coatings prepared by 3 methods exhibited different structures and components. ► The Ca–P coating weight increase depends on the apatite nucleation velocity. ► Surface hydrophilicity enhanced the velocity and quantity of apatite nucleation. ► The resulting Ca–P apatite coatings exhibit good biocompatibility to MG63 cells.

Evaluation of the 3D spatial distribution of the Calcium/Phosphorus ratio in bone using computed-tomography dual-energy analysis.

Science.gov (United States)

Hadjipanteli, A; Kourkoumelis, N; Fromme, P; Huang, J; Speller, R D

2016-01-01

The Calcium/Phosphorus (Ca/P) ratio was shown to vary between healthy bones and bones with osteoporotic symptoms. The relation of the Ca/P ratio to bone quality remains under investigation. To study this relation and determine if the ratio can be used to predict bone fractures, a non-invasive 3D imaging technique is required. The first aim of this study was to test the effectiveness of a computed-tomography dual-energy analysis (CT-DEA) technique developed to assess the Ca/P ratio in bone apatite (collagen-free bone) in identifying differences between healthy and inflammation-mediated osteoporotic (IMO) bones. The second aim was to extend the above technique for its application to a more complex structure, intact bone, that could potentially lead to clinical use. For the first aim, healthy and IMO rabbit cortical bone apatite samples were assessed. For the second aim, some changes were made to the technique, which was applied to healthy and IMO intact bone samples. Statistically significant differences between healthy and IMO bone apatite were found for the bulk Ca/P ratio, low Ca/P ratio proportion and interconnected low Ca/P ratio proportion. For the intact bone samples, the bulk Ca/P ratio was found to be significantly different between healthy and IMO. Results show that the CT-DEA technique can be used to identify differences in the Ca/P ratio between healthy and osteoporotic, in both bone apatite and intact bone. With quantitative imaging becoming an increasingly important advancement in medical imaging, CT-DEA for bone decomposition could potentially have several applications. Copyright © 2015. Published by Elsevier Ltd.

Strontium borate glass: potential biomaterial for bone regeneration.

Science.gov (United States)

Pan, H B; Zhao, X L; Zhang, X; Zhang, K B; Li, L C; Li, Z Y; Lam, W M; Lu, W W; Wang, D P; Huang, W H; Lin, K L; Chang, J

2010-07-06

Boron plays important roles in many life processes including embryogenesis, bone growth and maintenance, immune function and psychomotor skills. Thus, the delivery of boron by the degradation of borate glass is of special interest in biomedical applications. However, the cytotoxicity of borate glass which arises with the rapid release of boron has to be carefully considered. In this study, it was found that the incorporation of strontium into borate glass can not only moderate the rapid release of boron, but also induce the adhesion of osteoblast-like cells, SaOS-2, thus significantly increasing the cyto-compatibility of borate glass. The formation of multilayers of apatite with porous structure indicates that complete degradation is optimistic, and the spread of SaOS-2 covered by apatite to form a sandwich structure may induce bone-like tissue formation at earlier stages. Therefore, such novel strontium-incorporated borosilicate may act as a new generation of biomaterial for bone regeneration, which not only renders boron as a nutritious element for bone health, but also delivers strontium to stimulate formation of new bones.

Fabrication of mineralized electrospun PLGA and PLGA/gelatin nanofibers and their potential in bone tissue engineering.

Science.gov (United States)

Meng, Z X; Li, H F; Sun, Z Z; Zheng, W; Zheng, Y F

2013-03-01

Surface mineralization is an effective method to produce calcium phosphate apatite coating on the surface of bone tissue scaffold which could create an osteophilic environment similar to the natural extracellular matrix for bone cells. In this study, we prepared mineralized poly(D,L-lactide-co-glycolide) (PLGA) and PLGA/gelatin electrospun nanofibers via depositing calcium phosphate apatite coating on the surface of these nanofibers to fabricate bone tissue engineering scaffolds by concentrated simulated body fluid method, supersaturated calcification solution method and alternate soaking method. The apatite products were characterized by the scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FT-IR), and X-ray diffractometry (XRD) methods. A large amount of calcium phosphate apatite composed of dicalcium phosphate dihydrate (DCPD), hydroxyapatite (HA) and octacalcium phosphate (OCP) was deposited on the surface of resulting nanofibers in short times via three mineralizing methods. A larger amount of calcium phosphate was deposited on the surface of PLGA/gelatin nanofibers rather than PLGA nanofibers because gelatin acted as nucleation center for the formation of calcium phosphate. The cell culture experiments revealed that the difference of morphology and components of calcium phosphate apatite did not show much influence on the cell adhesion, proliferation and activity. Copyright © 2012 Elsevier B.V. All rights reserved.

Preliminary characterization of calcium chemical environment in apatitic and non-apatitic calcium phosphates of biological interest by X-ray absorption spectroscopy

International Nuclear Information System (INIS)

Eichert, D.; Salome, M.; Banu, M.; Susini, J.; Rey, C.

2005-01-01

Several reports have mentioned the existence of non-apatitic environments of phosphate and carbonate ions in synthetic and biological poorly crystalline apatites. However there were no direct spectroscopic evidences for the existence of non-apatitic environment of calcium ions. X-ray Absorption Spectroscopy, at the K-edge of calcium, allows the discrimination between different calcium phosphates of biological interest despite great spectral similarities. A primary analysis of the spectra reveals the existence, in synthetic poorly crystalline apatites, of variable features related to the maturation stage of the sample and corresponding to the existence of non-apatitic environments of calcium ions. Although these features can also be found in several other calcium phosphate salts, and do not allow a clear identification of the ionic environments of calcium ions, they give a possibility to directly determine the maturity of poorly crystalline apatite from calcium X-ray Absorption Near Edge Structure spectra

Uranium in fossil bones

International Nuclear Information System (INIS)

Koul, S.L.

1978-01-01

An attempt has been made to determine the uranium content and thus the age of certain fossil bones Haritalyangarh (Himachal Pradesh), India. The results indicate that bones rich in apatite are also rich in uranium, and that the radioactivity is due to radionuclides in the uranium series. The larger animals apparently have a higher concentration of uranium than the small. The dating of a fossil jaw (elephant) places it in the Pleistocene. (Auth.)

Fabrication of mineralized electrospun PLGA and PLGA/gelatin nanofibers and their potential in bone tissue engineering

Energy Technology Data Exchange (ETDEWEB)

Meng, Z.X. [Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001 (China); Li, H.F. [Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871 (China); Sun, Z.Z. [Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001 (China); Zheng, W., E-mail: zhengwei@hrbeu.edu.cn [Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001 (China); Zheng, Y.F., E-mail: yfzheng@pku.edu.cn [Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001 (China); Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871 (China)

2013-03-01

Surface mineralization is an effective method to produce calcium phosphate apatite coating on the surface of bone tissue scaffold which could create an osteophilic environment similar to the natural extracellular matrix for bone cells. In this study, we prepared mineralized poly(D,L-lactide-co-glycolide) (PLGA) and PLGA/gelatin electrospun nanofibers via depositing calcium phosphate apatite coating on the surface of these nanofibers to fabricate bone tissue engineering scaffolds by concentrated simulated body fluid method, supersaturated calcification solution method and alternate soaking method. The apatite products were characterized by the scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FT-IR), and X-ray diffractometry (XRD) methods. A large amount of calcium phosphate apatite composed of dicalcium phosphate dihydrate (DCPD), hydroxyapatite (HA) and octacalcium phosphate (OCP) was deposited on the surface of resulting nanofibers in short times via three mineralizing methods. A larger amount of calcium phosphate was deposited on the surface of PLGA/gelatin nanofibers rather than PLGA nanofibers because gelatin acted as nucleation center for the formation of calcium phosphate. The cell culture experiments revealed that the difference of morphology and components of calcium phosphate apatite did not show much influence on the cell adhesion, proliferation and activity. - Highlights: Black-Right-Pointing-Pointer Ca-P phases were coated on PLGA/gelatin electrospun nanofiber membranes within 3 h. Black-Right-Pointing-Pointer Ca-P coatings prepared by 3 methods exhibited different structures and components. Black-Right-Pointing-Pointer The Ca-P coating weight increase depends on the apatite nucleation velocity. Black-Right-Pointing-Pointer Surface hydrophilicity enhanced the velocity and quantity of apatite nucleation. Black-Right-Pointing-Pointer The resulting Ca-P apatite coatings exhibit good biocompatibility to MG63 cells.

Vascular and micro-environmental influences on MSC-coral hydroxyapatite construct-based bone tissue engineering.

Science.gov (United States)

Cai, Lei; Wang, Qian; Gu, Congmin; Wu, Jingguo; Wang, Jian; Kang, Ning; Hu, Jiewei; Xie, Fang; Yan, Li; Liu, Xia; Cao, Yilin; Xiao, Ran

2011-11-01

Bone tissue engineering (BTE) has been demonstrated an effective approach to generate bone tissue and repair bone defect in ectopic and orthotopic sites. The strategy of using a prevascularized tissue-engineered bone grafts (TEBG) fabricated ectopically to repair bone defects, which is called live bone graft surgery, has not been reported. And the quantitative advantages of vascularization and osteogenic environment in promoting engineered bone formation have not been defined yet. In the current study we generated a tissue engineered bone flap with a vascular pedicle of saphenous arteriovenous in which an organized vascular network was observed after 4 weeks implantation, and followed by a successful repaire of fibular defect in beagle dogs. Besides, after a 9 months long term observation of engineered bone formation in ectopic and orthotopic sites, four CHA (coral hydroxyapatite) scaffold groups were evaluated by CT (computed tomography) analysis. By the comparison of bone formation and scaffold degradation between different groups, the influences of vascularization and micro-environment on tissue engineered bone were quantitatively analyzed. The results showed that in the first 3 months vascularization improved engineered bone formation by 2 times of non-vascular group and bone defect micro-environment improved it by 3 times of ectopic group, and the CHA-scaffold degradation was accelerated as well. Copyright © 2011 Elsevier Ltd. All rights reserved.

HERSCHEL OBSERVATIONS OF THE T CHA TRANSITION DISK: CONSTRAINING THE OUTER DISK PROPERTIES

OpenAIRE

Cieza, Lucas A.; Olofsson, Johan; Harvey, Paul M.; Pinte, Christophe; Merin, Bruno; Augereau, Jean-Charles; Evans, Neal J., II; Najita, Joan; Henning, Thomas; Menard, Francois

2011-01-01

T Cha is a nearby (d = 100 pc) transition disk known to have an optically thin gap separating optically thick inner and outer disk components. Huelamo et al. (2011) recently reported the presence of a low-mass object candidate within the gap of the T Cha disk, giving credence to the suspected planetary origin of this gap. Here we present the Herschel photometry (70, 160, 250, 350, and 500 micron) of T Cha from the "Dust, Ice, and Gas in Time" (DIGIT) Key Program, which bridges the wavelength ...

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)

Inverted Apatite (U-Th)/He and Fission-track Dates from the Rae craton, Baffin Island, Canada and Implications for Apatite Radiation Damage-He Diffusivity Models

Science.gov (United States)

Ault, A. K.; Reiners, P. W.; Thomson, S. N.; Miller, G. H.

2015-12-01

Coupled apatite (U-Th)/He and fission-track (AFT) thermochronology data from the same sample can be used to decipher complex low temperature thermal histories and evaluate compatibility between these two methods. Existing apatite He damage-diffusivity models parameterize radiation damage annealing as fission-track annealing and yield inverted apatite He and AFT dates for samples with prolonged residence in the He partial retention zone. Apatite chemistry also impacts radiation damage and fission-track annealing, temperature sensitivity, and dates in both systems. We present inverted apatite He and AFT dates from the Rae craton, Baffin Island, Canada, that cannot be explained by apatite chemistry or existing damage-diffusivity and fission track models. Apatite He dates from 34 individual analyses from 6 samples range from 237 ± 44 Ma to 511 ± 25 Ma and collectively define a positive date-eU relationship. AFT dates from these same samples are 238 ± 15 Ma to 350 ± 20 Ma. These dates and associated track length data are inversely correlated and define the left segment of a boomerang diagram. Three of the six samples with 20-90 ppm eU apatite grains yield apatite He and AFT dates inverted by 300 million years. These samples have average apatite Cl chemistry of ≤0.02 wt.%, with no correlation between Cl content and Dpar. Thermal history simulations using geologic constraints, an apatite He radiation damage accumulation and annealing model, apatite He dates with the range of eU values, and AFT date and track length data, do not yield any viable time-temperature paths. Apatite He and AFT data modeled separately predict thermal histories with Paleozoic-Mesozoic peaks reheating temperatures differing by ≥15 °C. By modifying the parameter controlling damage annealing (Rmr0) from the canonical 0.83 to 0.5-0.6, forward models reproduce the apatite He date-eU correlation and AFT dates with a common thermal history. Results imply apatite radiation damage anneals at

Heating the Primordial Soup: X-raying the Circumstellar Disk of T Cha

Science.gov (United States)

Principe, David; Huenemoerder, D.; Kastner, J. H.; Bessell, M. S.; Sacco, G.

2014-01-01

The classical T Tauri Star (cTTS) T Chamaeleontis (T Cha) presents a unique opportunity to probe pre-main sequence star-disk interactions and late-stage circumstellar disk evolution. T Cha is the only known example of a nearly edge-on, actively accreting star/disk system within ~110 pc, and furthermore may be orbited by a low-mass companion or massive planet that has cleared an inner hole in its disk. The star is characterized by strong variability in the optical 3 magnitudes in the V band) as well as large and variable extinction (AV in the range of 1-5). Like most cTTS, T Cha is also a luminous X-ray source. We present preliminary results of two observations (totaling 150 ks) of T Cha with Chandra’s HETGS. Our motivations are to (a) determine the intrinsic X-ray spectrum of T Cha, so as to establish whether its X-ray emission can be attributed to accretion shocks, coronal emission, or a combination; (b) investigate whether its X-ray flux exhibits modulation that may be related to the stellar rotational period 3.3 days); and (c) take advantage of the nearly-edge-on disk viewing geometry to model the spectrum of X-rays absorbed by the gaseous disk orbiting T Cha. These results will serve as much-needed input to models of magnetospheric accretion and irradiated, planet-forming disks. This research is supported via award number GO3-14022X to RIT issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of NASA under contract NAS803060. Additional support is provided by National Science Foundation grant AST-1108950 to RIT.

Disparities in correlating microstructural to nanostructural preservation of dinosaur femoral bones

Science.gov (United States)

Kim, Jung-Kyun; Kwon, Yong-Eun; Lee, Sang-Gil; Lee, Ji-Hyun; Kim, Jin-Gyu; Huh, Min; Lee, Eunji; Kim, Youn-Joong

2017-03-01

Osteohistological researches on dinosaurs are well documented, but descriptions of direct correlations between the bone microstructure and corresponding nanostructure are currently lacking. By applying correlative microscopy, we aimed to verify that well-preserved osteohistological features correlate with pristine fossil bone nanostructures from the femoral bones of Koreanosaurus boseongensis. The quality of nanostructural preservation was evaluated based on the preferred orientation level of apatite crystals obtained from selected area electron diffraction (SAED) patterns and by measuring the “arcs” from the {100} and {002} diffraction rings. Unlike our expectations, our results revealed that well-preserved microstructures do not guarantee pristine nanostructures and vice versa. Structural preservation of bone from macro- to nanoscale primarily depends on original bioapatite density, and subsequent taphonomical factors such as effects from burial, pressure, influx of external elements and the rate of diagenetic alteration of apatite crystals. Our findings suggest that the efficient application of SAED analysis opens the opportunity for comprehensive nanostructural investigations of bone.

Scaffolds of hydroxyl apatite nanoparticles disseminated in 1, 6-diisocyanatohexane-extended poly(1, 4-butylene succinate)/poly(methyl methacrylate) for bone tissue engineering

International Nuclear Information System (INIS)

Kaur, Kulwinder; Singh, K.J.; Anand, Vikas; Bhatia, Gaurav; Kaur, Raminderjit; Kaur, Manpreet; Nim, Lovedeep; Arora, Daljit Singh

2017-01-01

Poly(1, 4-butyl succinate) extended 1, 6-diisocyanatohexane (PBSu-DCH) polymers and Polymethylmethacrylate (PMMA) scaffolds decorated with nano hydroxyl apatite have been prepared and characterized for regeneration of bone in cranio-maxillofacial region. Synthesized scaffolds revealed good response in bone regeneration and excellent cell viability in comparison to commercial available glass plate, which lead to better proliferation of MG-63 cell lines. Additionally, they demonstrate high porosity and excellent water retention ability. Moreover, controlled degradation (in pH = 7.4) and sustained drug release in pH (4.5 and 7.4) are advantages of these scaffolds to serve as delivery vehicles for therapeutic drugs. Samples also provide the protection against Escherichia coli and Methicillin Resistant Staphylococcus aureus microorganisms which can be helpful for quick recovery of the patient. In-vitro inflammatory response has been assessed via adsorption of human plasma/serum proteins on the surface of the scaffolds. Results suggest that prepared scaffolds have good bone regeneration ability and provide friendly environment for the cell growth with the additional advantage of protection of the surrounding tissues from microbial infection. With all these features, it is speculated that these scaffolds will have wide utility in the area of tissue engineering and regenerative medicine. - Highlights: • Porous scaffolds have been prepared by solvent casting technique. • Scaffolds have shown good antibacterial activity against gram positive and negative microorganisms. • Synthesized scaffolds may find applications in the area of regenerative medicine.

Scaffolds of hydroxyl apatite nanoparticles disseminated in 1, 6-diisocyanatohexane-extended poly(1, 4-butylene succinate)/poly(methyl methacrylate) for bone tissue engineering

Energy Technology Data Exchange (ETDEWEB)

Kaur, Kulwinder [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India); Singh, K.J., E-mail: kanwarjitsingh@yahoo.com [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India); Anand, Vikas [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India); Bhatia, Gaurav; Kaur, Raminderjit [Department of Molecular Biology and Biochemistry, Guru Nanak Dev University, Amritsar 143005 (India); Kaur, Manpreet [Department of Human Genetics, Guru Nanak Dev University, Amritsar 143005 (India); Nim, Lovedeep; Arora, Daljit Singh [Department of Microbiology, Guru Nanak Dev University, Amritsar 143005 (India)

2017-02-01

Poly(1, 4-butyl succinate) extended 1, 6-diisocyanatohexane (PBSu-DCH) polymers and Polymethylmethacrylate (PMMA) scaffolds decorated with nano hydroxyl apatite have been prepared and characterized for regeneration of bone in cranio-maxillofacial region. Synthesized scaffolds revealed good response in bone regeneration and excellent cell viability in comparison to commercial available glass plate, which lead to better proliferation of MG-63 cell lines. Additionally, they demonstrate high porosity and excellent water retention ability. Moreover, controlled degradation (in pH = 7.4) and sustained drug release in pH (4.5 and 7.4) are advantages of these scaffolds to serve as delivery vehicles for therapeutic drugs. Samples also provide the protection against Escherichia coli and Methicillin Resistant Staphylococcus aureus microorganisms which can be helpful for quick recovery of the patient. In-vitro inflammatory response has been assessed via adsorption of human plasma/serum proteins on the surface of the scaffolds. Results suggest that prepared scaffolds have good bone regeneration ability and provide friendly environment for the cell growth with the additional advantage of protection of the surrounding tissues from microbial infection. With all these features, it is speculated that these scaffolds will have wide utility in the area of tissue engineering and regenerative medicine. - Highlights: • Porous scaffolds have been prepared by solvent casting technique. • Scaffolds have shown good antibacterial activity against gram positive and negative microorganisms. • Synthesized scaffolds may find applications in the area of regenerative medicine.

CHaMP metrics - Columbia Habitat Monitoring Program

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The goal of CHaMP is to generate and implement a standard set of fish habitat monitoring (status and trend) methods in up to 26 watersheds across the Columbia River...

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

International Nuclear Information System (INIS)

Zhang Hua; Ye Xiaojian; Li Jiashun

2009-01-01

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.

The improved biological response of shark tooth bioapatites in a comparative in vitro study with synthetic and bovine bone grafts.

Science.gov (United States)

López-Álvarez, M; Pérez-Davila, S; Rodríguez-Valencia, C; González, P; Serra, J

2016-06-07

Autologous bone is considered to be the gold standard for bone tissue regeneration, providing more highly efficient functional responses compared to synthetic materials, and avoiding the rejection risks of allogenic grafts. However, it presents limitations for certain types of surgery due to its high resorption levels and donor site morbidity. Different biphasic synthetic composites, based onnon-apatitic calcium phosphates enriched with apatitic phases-such as hydroxyapatite, and bioderived bone grafts of bovine and porcine origin-are proposed as lower resorption materials due to their higher crystalline structure. The present work proposes two new sources of bioapatites for bone filler applications obtained from the dentine and enameloid of shark teeth, respectively. These bioapatites each present a characteristic apatite-based composition and additional enrichments of specific trace elements, such as magnesium and fluorine, with proven roles in bone metabolism. Their processing and physicochemical characterization (SEM, FT-Raman and XRD) is presented, together with an in vitro evaluation of osteogenic activity compared to a commercial bovine mineralized matrix and synthetic HA/β TCP grafts. The results proved the globular morphology (0.5-1.5 μm) and porosity (~50 μm and ~0.5-1 μm) of shark dentine bioapatites with biphasic composition: apatitic (hydroxyapatite and apatite-(CaF)), non-apatitic (whitlockite), and an apatitic phase (fluorapatite), organized in oriented crystals in enameloid bioapatites. An evaluation of the pre-osteoblast MC3T3-E1 morphology revealed the colonization of pores in dentine bioapatites and an aligned cell growth in the oriented enameloid crystals. A higher proliferation (p  <  0.01) was detected at up to 21 d in both the shark bioapatites and synthetic biphasic graft with respect to the bovine mineralized matrix. Finally, the great potential of porous biphasic dentine bioapatites enriched with Mg and the aligned

Ultra-structural defects cause low bone matrix stiffness despite high mineralization in osteogenesis imperfecta mice.

Science.gov (United States)

Vanleene, Maximilien; Porter, Alexandra; Guillot, Pascale-Valerie; Boyde, Alan; Oyen, Michelle; Shefelbine, Sandra

2012-06-01

Bone is a complex material with a hierarchical multi-scale organization from the molecule to the organ scale. The genetic bone disease, osteogenesis imperfecta, is primarily caused by mutations in the collagen type I genes, resulting in bone fragility. Because the basis of the disease is molecular with ramifications at the whole bone level, it provides a platform for investigating the relationship between structure, composition, and mechanics throughout the hierarchy. Prior studies have individually shown that OI leads to: 1. increased bone mineralization, 2. decreased elastic modulus, and 3. smaller apatite crystal size. However, these have not been studied together and the mechanism for how mineral structure influences tissue mechanics has not been identified. This lack of understanding inhibits the development of more accurate models and therapies. To address this research gap, we used a mouse model of the disease (oim) to measure these outcomes together in order to propose an underlying mechanism for the changes in properties. Our main finding was that despite increased mineralization, oim bones have lower stiffness that may result from the poorly organized mineral matrix with significantly smaller, highly packed and disoriented apatite crystals. Using a composite framework, we interpret the lower oim bone matrix elasticity observed as the result of a change in the aspect ratio of apatite crystals and a disruption of the crystal connectivity. Copyright © 2012 Elsevier Inc. All rights reserved.

Chaînes logistiques et consommation d'énergie : cas du yaourt et du jean

OpenAIRE

Rizet , C.; Keita , Basile

2005-01-01

Contrat INRETS/ADEME n°: 0203034; Rapport de recherche; Pour analyser l'efficacité énergétique et les émissions de GES des chaînes logistiques, on compare différentes chaînes aboutissant aux mêmes consommateurs. Deux produits sont étudiés : le yaourt, caractéristique de la chaîne du froid et des flux tendus et le blue jean, intégré au marché mondial, tant pour sa matière première principale (le coton) que pour les différentes étapes de sa fabrication. Les chaînes étudiées pour le jean différe...

Favoriser le développement de chaînes de valeur agricoles ...

International Development Research Centre (IDRC) Digital Library (Canada)

Favoriser le développement de chaînes de valeur agricoles inclusives et durables grâce aux TIC ... Ce projet vise à mettre l'information et les connaissances au service du développement de chaînes de valeur agricoles grâce à l'utilisation stratégique des TIC. ... Tropical Agriculture Research and Higher Education Center.

Heart failure: a weak link in CHA2 DS2 -VASc.

Science.gov (United States)

Friberg, Leif; Lund, Lars H

2018-02-15

In atrial fibrillation, stroke risk is assessed by the CHA 2 DS 2 -VASc score. Heart failure is included in CHA 2 DS 2 -VASc, but the rationale is uncertain. Our objective was to test if heart failure is a risk factor for stroke, independent of other risk factors in CHA 2 DS 2 -VASc. We studied 300 839 patients with atrial fibrillation in the Swedish Patient Register 2005-11. Three definitions of heart failure were used in order to assess the robustness of the results. In the main analysis, heart failure was defined by a hospital discharge diagnosis of heart failure as first or second diagnosis and a filled prescription of a diuretic within 3 months before index + 30 days. The second definition counted first or second discharge diagnoses failure diagnosis in open or hospital care before index + 30 days. Associations with outcomes were assessed with multivariable Cox analyses. Patients with heart failure were older (80.5 vs. 74.0 years, P failure and 3.1% without. Adjustment for the cofactors in CHA 2 DS 2 -VASc eradicated the difference in stroke risk between patients with and without heart failure (hazard ratio 1.01 with 95% confidence interval 0.96-1.05). The area under the receiver operating characteristic curve for CHA 2 DS 2 -VASc was not improved by points for heart failure. A clinical diagnosis of heart failure was not an independent risk factor for stroke in patients with atrial fibrillation, which may have implications for anticoagulation management. © 2018 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of the European Society of Cardiology.

The oxidation state of sulfur in apatite: A new oxybarometer?

Science.gov (United States)

Fiege, A.; Konecke, B.; Kim, Y.; Simon, A. C.; Becker, U.; Parat, F.

2016-12-01

Oxygen fugacity (fO2) of magmatic and hydrothermal systems influences, for instance, crystallization and degassing processes as well as metal solubilities in melts and fluids. Apatite is a ubiquitous mineral in magmatic and hydrothermal environments that can record and preserve volatile zonation. It can contain several thousand μg/g of the redox sensitive element sulfur (S), making S-in-apatite a potential fO2 sensor. Despite the polyvalent properties of S (e.g., S2-, S4+, S6+), the oxidation state and incorporation mechanisms of S in the apatite structure are poorly understood. In this study, the oxidation state of S-in-apatite as a function of fO2 is investigated using X-ray absorption near-edge structures (XANES) spectroscopy at the S K-edge. Apatites crystallized from lamproitic melts at 1000°C, 300 MPa and over a broad range of fO2 and sulfur fugacities (fS2) were measured. Peaks corresponding to S6+ ( 2482 eV), S4+ ( 2478 eV) and S2- ( 2470 eV) were identified in apatite. The integrated S6+/STotal (STotal = S6+ + S4+ + S2-) peak area ratios show a distinct positive correlation with fO2, increasing from 0.17 at FMQ+0 to 0.96 at FMQ+3. Ab-initio calculations were performed to further understand the energetics and geometry of incorporation of S6+, S4+ and S2- into the apatite (F-, Cl-, OH-) end-members. The results confirm that apatite can contain three different oxidations states of S (S6+, S4+, S2-) as a function of fO2. This makes apatite probably the first geologically relevant mineral to incorporate reduced (S2-), intermediate (S4+), and oxidized (S6+) S in variable proportions. We emphasize that the strong dependence of the S oxidation state in apatite as a function of fO2 is also coupled with changing S content of apatite and co-existing melt (i.e., with changing fS2), resulting in a complex correlation between [1] apatite-melt (or fluid) partitioning, [2] redox conditions and [3] the melt and/or fluid composition, making the application of previously

A protocol for pressurized liquid extraction and processing methods to isolate modern and ancient bone cholesterol for compound-specific stable isotope analysis.

Science.gov (United States)

Laffey, Ann O; Krigbaum, John; Zimmerman, Andrew R

2017-02-15

Bone lipid compound-specific isotope analysis (CSIA) and bone collagen and apatite stable isotope ratio analysis are important sources of ecological and paleodietary information. Pressurized liquid extraction (PLE) is quicker and utilizes less solvent than traditional methods of lipid extraction such as soxhlet and ultrasonication. This study facilitates dietary analysis by optimizing and testing a standardized methodology for PLE of bone cholesterol. Modern and archaeological bones were extracted by PLE using varied temperatures, solvent solutions, and sample weights. The efficiency of PLE was assessed via quantification of cholesterol yields. Stable isotopic ratio integrity was evaluated by comparing isotopic signatures (δ 13 C and δ 18 O values) of cholesterol derived from whole bone, bone collagen and bone apatite. Gas chromatography/mass spectrometry (GC/MS) and gas chromatography isotope ratio mass spectrometry (GC/IRMS) were conducted on purified collagen and lipid extracts to assess isotopic responses to PLE. Lipid yield was optimized at two PLE extraction cycles of 75 °C using dichloromethane/methanol (2:1 v/v) as a solvent with 0.25-0.75 g bone sample. Following lipid extraction, saponification combined with the derivatization of the neutral fraction using trimethylsilylation yielded nearly twice the cholesterol of non-saponified or non-derivatized samples. It was also found that lipids extracted from purified bone collagen and apatite could be used for cholesterol CSIA. There was no difference in the bulk δ 13 C values of collagen extracted from bone with or without lipid. However, there was a significant depletion in 18 O of bone apatite due to lipid presence or processing. These results should assist sample selection and provide an effective, alternative extraction method for bone cholesterol that may be used for isotopic and paleodietary analysis. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Polycrystalline apatite synthesized by hydrothermal replacement of calcium carbonates

Science.gov (United States)

Kasioptas, Argyrios; Geisler, Thorsten; Perdikouri, Christina; Trepmann, Claudia; Gussone, Nikolaus; Putnis, Andrew

2011-06-01

Aragonite and calcite single crystals can be readily transformed into polycrystalline hydroxyapatite pseudomorphs by hydrothermal treatment in a (NH 4) 2HPO 4 solution. Scanning electron microscopy of the reaction products showed that the transformation of aragonite to apatite is characterised by the formation of a sharp interface between the two phases and by the development of intracrystalline porosity in the hydroxyapatite phase. In addition, electron backscattered diffraction (EBSD) imaging showed that the c-axis of apatite is predominantly oriented perpendicular to the reaction front with no crystallographic relationship to the aragonite lattice. However, the Ca isotopic composition of the parent aragonite, measured by thermal ionization mass spectrometry was inherited by the apatite product. Hydrothermal experiments conducted with use of phosphate solutions prepared with water enriched in 18O (97%) further revealed that the 18O from the solution is incorporated in the product apatite, as measured by micro-Raman spectroscopy. Monitoring the distribution of 18O with Raman spectroscopy was possible because the incorporation of 18O in the PO 4 group of apatite generates four new Raman bands at 945.8, 932, 919.7 and 908.8 cm -1, in addition to the ν1(PO 4) symmetric stretching band of apatite located at 962 cm -1, which can be assigned to four 18O-bearing PO 4 species. The relative intensities of these bands reflect the 18O content in the PO 4 group of the apatite product. By using equilibrated and non-equilibrated solutions, with respect to the 18O distribution between aqueous phosphate and water, we could show that the concentration of 18O in the apatite product is linked to the degree of 18O equilibration in the solution. The textural and chemical observations are indicative of a coupled mechanism of aragonite dissolution and apatite precipitation taking place at a moving reaction interface.

Nanomechanical mapping of bone tissue regenerated by magnetic scaffolds.

Science.gov (United States)

Bianchi, Michele; Boi, Marco; Sartori, Maria; Giavaresi, Gianluca; Lopomo, Nicola; Fini, Milena; Dediu, Alek; Tampieri, Anna; Marcacci, Maurilio; Russo, Alessandro

2015-01-01

Nanoindentation can provide new insights on the maturity stage of regenerating bone. The aim of the present study was the evaluation of the nanomechanical properties of newly-formed bone tissue at 4 weeks from the implantation of permanent magnets and magnetic scaffolds in the trabecular bone of rabbit femoral condyles. Three different groups have been investigated: MAG-A (NdFeB magnet + apatite/collagen scaffold with magnetic nanoparticles directly nucleated on the collagen fibers during scaffold synthesis); MAG-B (NdFeB magnet + apatite/collagen scaffold later infiltrated with magnetic nanoparticles) and MAG (NdFeB magnet). The mechanical properties of different-maturity bone tissues, i.e. newly-formed immature, newly-formed mature and native trabecular bone have been evaluated for the three groups. Contingent correlations between elastic modulus and hardness of immature, mature and native bone have been examined and discussed, as well as the efficacy of the adopted regeneration method in terms of "mechanical gap" between newly-formed and native bone tissue. The results showed that MAG-B group provided regenerated bone tissue with mechanical properties closer to that of native bone compared to MAG-A or MAG groups after 4 weeks from implantation. Further, whereas the mechanical properties of newly-formed immature and mature bone were found to be fairly good correlated, no correlation was detected between immature or mature bone and native bone. The reported results evidence the efficacy of nanoindentation tests for the investigation of the maturity of newly-formed bone not accessible through conventional analyses.

Fabrication of highly porous biodegradable biomimetic nanocomposite as advanced bone tissue scaffold

OpenAIRE

Abdalla Abdal-hay; Khalil Abdelrazek Khalil; Abdel Salam Hamdy; Fawzi F. Al-Jassir

2017-01-01

Development of bioinspired or biomimetic materials is currently a challenge in the field of tissue regeneration. In-situ 3D biomimetic microporous nanocomposite scaffold has been developed using a simple lyophilization post hydrothermal reaction for bone healing applications. The fabricated 3D porous scaffold possesses advantages of good bonelike apatite particles distribution, thermal properties and high porous interconnected network structure. High dispersion bonelike apatite nanoparticles ...

Appearance of cell-adhesion factor in osteoblast proliferation and differentiation of apatite coating titanium by blast coating method.

Science.gov (United States)

Umeda, Hirotsugu; Mano, Takamitsu; Harada, Koji; Tarannum, Ferdous; Ueyama, Yoshiya

2017-08-01

We have already reported that the apatite coating of titanium by the blast coating (BC) method could show a higher rate of bone contact from the early stages in vivo, when compared to the pure titanium (Ti) and the apatite coating of titanium by the flame spraying (FS) method. However, the detailed mechanism by which BC resulted in satisfactory bone contact is still unknown. In the present study, we investigated the importance of various factors including cell adhesion factor in osteoblast proliferation and differentiation that could affect the osteoconductivity of the BC disks. Cell proliferation assay revealed that Saos-2 could grow fastest on BC disks, and that a spectrophotometric method using a LabAssay TM ALP kit showed that ALP activity was increased in cells on BC disks compared to Ti disks and FS disks. In addition, higher expression of E-cadherin and Fibronectin was observed in cells on BC disks than Ti disks and FS disks by relative qPCR as well as Western blotting. These results suggested that the expression of cell-adhesion factors, proliferation and differentiation of osteoblast might be enhanced on BC disks, which might result higher osteoconductivity.

Development of a service organization. CHA (Catholic Hospital Association) from post-World War II through Vatican II.

Science.gov (United States)

Kauffman, C J

1990-06-01

Having weathered the Depression and war years, CHA in the late 1940s looked forward to a new era in Catholic healthcare. The third and fourth articles of Health Progress's six-part history of CHA described how Rev. Alphonse M. Schwitalla, SJ, led the association through one of the most difficult periods in U.S. history. This article follows CHA's development into a modern service organization under the leadership of Rev. John J. Flanagan, SJ. The series' final installment, which will appear in the July-August issue, describes how CHA has modernized its services and structure in the past two decades to help its members adjust to a turbulent environment.

Structurally bound sulfide and sulfate in apatite from the Philips Mine iron oxide - apatite deposit, New York, USA: A tracer of redox changes

Science.gov (United States)

Sadove, G.; Konecke, B.; Fiege, A.; Simon, A. C.

2017-12-01

Multiple competing hypotheses attempt to explain the genesis of iron oxide-apatite (IOA) ore deposits. Many studies have investigated the chemistry of apatite because the abundances of F and Cl can distinguish magmatic vs. hydrothermal processes. Recent experiments demonstrate that apatite incorporates S6+, S4+, and S2-, and that total sulfur (∑S) as well as the S6+/∑S ratio in apatite vary systematically as a function of oxygen fugacity [1], providing information about sulfur budget and redox. Here, we present results from X-ray absorption near-edge structure (XANES) spectroscopy at the S K-edge, electron microprobe analyses, cathodoluminescence (CL) imaging, and element mapping of apatite from the Philip's Mine IOA deposit, southern Adirondack Mountains, USA. The Philip's Mine apatite contains inclusions of pyrite and pyrrhotite, where the latter includes iron oxide and Ni-rich domains. The apatite also contains inclusions of monazite, and exhibits complex CL zonation coincident with variations in the abundances of REE and S. The presence of monazite fingerprints fluid-mediated dissolution-reprecipitation of originally REE-enriched apatite [2]. The S XANES spectra reveal varying proportions of structurally bound S6+ and S2-, as the S6+/∑S ratio ranges from sulfide-only to sulfate-only. Notably, sulfide-dominated domains contain higher S contents than sulfate-dominated regions. These observations are consistent with co-crystallization of apatite and monosulfide solid solution (MSS) at reducing conditions, followed by decomposition of MSS to pyrrhotite, pyrite and intermediate solid solution (ISS, which is not preserved; [3]). Metasomatism of that assemblage by an oxidized fluid resulted in formation of monazite in apatite and iron oxide domains in pyrrhotite. We conclude that the deposit formed by a H2S-Fe-rich volatile phase, possibly evolved from a rather primitive magmatic source, which is consistent with the low Ti content of magnetite. The deposit was

Immobilization of uranium in contaminated soil by natural apatite addition

International Nuclear Information System (INIS)

Mrdakovic Popic, Jelena; Stojanovic, Mirjana; Milosevic, Sinisa; Iles, Deana; Zildzovic, Snezana

2007-01-01

Available in abstract form only. Full text of publication follows: The goal of this study was to evaluate the effectiveness of Serbian natural mineral apatite as soil additive for reducing the migration of uranium from contaminated sediments. In laboratory study we investigated the sorption properties of domestic apatite upon different experimental conditions, such as pH, adsorbent mass, reaction period, concentration of P 2 O 5 in apatite, solid/liquid ratio. In second part of study, we did the quantification of uranium in soil samples, taken from uranium mine site 'Kalna', by sequential extraction method. The same procedure was, also, used for uranium determination in contaminated soil samples after apatite addition, in order to determine the changes in U distribution in soil fraction. The obtained results showed the significant level of immobilization (96.7%) upon certain conditions. Increase of %P 2 O 5 in apatite and process of mechano-chemical activation led to increase of immobilization capacity from 17.50% till 91.64%. The best results for uranium binding were obtained at pH 5.5 and reaction period 60 days (98.04%) The sequential extraction showed the presence of uranium (48.2%) in potentially available soil fractions, but with the apatite addition uranium content in these fractions decreased (30.64%), what is considering environmental aspect significant fact. In situ immobilization of radionuclide using inexpensive sequestering agents, such as apatite, is very adequate for big contaminated areas of soil with low level of contamination. This investigation study on natural apatite from deposit 'Lisina' Serbia was the first one of this type in our country. Key words: apatite, uranium, immobilization, soil, contamination. (authors)

Nucleosome structure of the yeast CHA1 promoter

DEFF Research Database (Denmark)

Moreira, José Manuel Alfonso; Holmberg, S

1998-01-01

conditions. Five yeast TBP mutants defective in different steps in activated transcription abolished CHA1 expression, but failed to affect induction-dependent chromatin rearrangement of the promoter region. Progressive truncations of the RNA polymerase II C-terminal domain caused a progressive reduction...

Effect of strontium ranelate on bone mineral: Analysis of nanoscale compositional changes.

Science.gov (United States)

Rossi, André L; Moldovan, Simona; Querido, William; Rossi, Alexandre; Werckmann, Jacques; Ersen, Ovidiu; Farina, Marcos

2014-01-01

Strontium ranelate has been used to prevent bone loss and stimulate bone regeneration. Although strontium may integrate into the bone crystal lattice, the chemical and structural modifications of the bone when strontium interacts with the mineral phase are not completely understood. The objective of this study was to evaluate apatite from the mandibles of rats treated with strontium ranelate in the drinking water and compare its characteristics with those from untreated rats and synthetic apatites with and without strontium. Electron energy loss near edge structures from phosphorus, carbon, calcium and strontium were obtained by electron energy loss spectroscopy in a transmission electron microscope. The strontium signal was detected in the biological and synthetic samples containing strontium. The relative quantification of carbon by analyzing the CK edge at an energy loss of ΔE = 284 eV showed an increase in the number of carbonate groups in the bone mineral of treated rats. A synthetic strontium-containing sample used as control did not exhibit a carbon signal. This study showed physicochemical modifications in the bone mineral at the nanoscale caused by the systemic administration of strontium ranelate. Copyright © 2013 Elsevier Ltd. All rights reserved.

The healing of fractured bones

Energy Technology Data Exchange (ETDEWEB)

Bacon, G E [Central Electricity Generating Board, Cheltenham (United Kingdom)

1997-04-01

A method utilising neutron beams of width 1 mm, used on D1B (2.4 A) and D20 (1.3 A) to study the healing of fractured bones is presented. It is found that the callus bone uniting the fractured tibia of a sheep, whose healing had been encouraged by daily mechanical vibration over a period of three months, showed no trace of the large preferential vertical orientation of the apatite crystals which is characteristic of the normal bone. Nevertheless the bone had regained about 60% of its mechanical strength and the callus bone, although not oriented, was well crystallized. It is considered that the new monochromator for D20, expected to give increased intensity at 2.5 A, will be of considerable advantage. (author). 2 refs.

Predictive performance of the CHA2DS2-VASc rule in atrial fibrillation : a systematic review and meta-analysis

NARCIS (Netherlands)

Van Doorn, S.; Debray, T. P. A.; Kaasenbrood, F.; Hoes, A. W.; Rutten, F. H.; Moons, K. G. M.; Geersing, G. J.

2017-01-01

Essentials The widely recommended CHA2DS2-VASc shows conflicting results in contemporary validation studies. We performed a systematic review and meta-analysis of 19 studies validating CHA2DS2-VASc. There was high heterogeneity in stroke risks for different CHA2DS2-VASc scores. This was not

Intraclonal genome diversity of Pseudomonas aeruginosa clones CHA and TB

Science.gov (United States)

2013-01-01

Background Adaptation of Pseudomonas aeruginosa to different living conditions is accompanied by microevolution resulting in genomic diversity between strains of the same clonal lineage. In order to detect the impact of colonized habitats on P. aeruginosa microevolution we determined the genomic diversity between the highly virulent cystic fibrosis (CF) isolate CHA and two temporally and geographically unrelated clonal variants. The outcome was compared with the intraclonal genome diversity between three more closely related isolates of another clonal complex. Results The three clone CHA isolates differed in their core genome in several dozen strain specific nucleotide exchanges and small deletions from each other. Loss of function mutations and non-conservative amino acid replacements affected several habitat- and lifestyle-associated traits, for example, the key regulator GacS of the switch between acute and chronic disease phenotypes was disrupted in strain CHA. Intraclonal genome diversity manifested in an individual composition of the respective accessory genome whereby the highest number of accessory DNA elements was observed for isolate PT22 from a polluted aquatic habitat. Little intraclonal diversity was observed between three spatiotemporally related outbreak isolates of clone TB. Although phenotypically different, only a few individual SNPs and deletions were detected in the clone TB isolates. Their accessory genome mainly differed in prophage-like DNA elements taken up by one of the strains. Conclusions The higher geographical and temporal distance of the clone CHA isolates was associated with an increased intraclonal genome diversity compared to the more closely related clone TB isolates derived from a common source demonstrating the impact of habitat adaptation on the microevolution of P. aeruginosa. However, even short-term habitat differentiation can cause major phenotypic diversification driven by single genomic variation events and uptake of phage

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.

Study of the auto-irradiation effects in apatites structure materials

International Nuclear Information System (INIS)

Soulet, St.

2000-11-01

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

Comparative study on inorganic composition and crystallographic properties of cortical and cancellous bone.

Science.gov (United States)

Wang, Xiao-Yan; Zuo, Yi; Huang, Di; Hou, Xian-Deng; Li, Yu-Bao

2010-12-01

To comparatively investigate the inorganic composition and crystallographic properties of cortical and cancellous bone via thermal treatment under 700 °C. Thermogravimetric measurement, infrared spectrometer, X-ray diffraction, chemical analysis and X-ray photo-electron spectrometer were used to test the physical and chemical properties of cortical and cancellous bone at room temperature 250 °C, 450 °C, and 650 °C, respectively. The process of heat treatment induced an extension in the a-lattice parameter and changes of the c-lattice parameter, and an increase in the crystallinity reflecting lattice rearrangement after release of lattice carbonate and possible lattice water. The mineral content in cortical and cancellous bone was 73.2wt% and 71.5wt%, respectively. For cortical bone, the weight loss was 6.7% at the temperature from 60 °C to 250 °C, 17.4% from 250 °C to 450 °C, and 2.7% from 450 °C to 700 °C. While the weight loss for the cancellous bone was 5.8%, 19.9%, and 2.8 % at each temperature range, the Ca/P ratio of cortical bone was 1.69 which is higher than the 1.67 of stoichiometric HA due to the B-type CO₃²⁻ substitution in apatite lattice. The Ca/P ratio of cancellous bone was lower than 1.67, suggesting the presence of more calcium deficient apatite. The collagen fibers of cortical bone were arrayed more orderly than those of cancellous bone, while their mineralized fibers ollkded similar. The minerals in both cortical and cancellous bone are composed of poorly crystallized nano-size apatite crystals with lattice carbonate and possible lattice water. The process of heat treatment induces a change of the lattice parameter, resulting in lattice rearrangement after the release of lattice carbonate and lattice water and causing an increase in crystal size and crystallinity. This finding is helpful for future biomaterial design, preparation and application. Copyright © 2010 The Editorial Board of Biomedical and Environmental Sciences

Effect of akermanite morphology on precipitation of bone-like apatite

International Nuclear Information System (INIS)

Hou Xiaoni; Yin Guangfu; Chen Xianchun; Liao Xiaoming; Yao Yadong; Huang Zhongbin

2011-01-01

Bioactivity in vivo of ceramic materials has been related to their surface micro-topography and may be estimated by means of simulated body fluid method in vitro. In order to investigate the effect of surface topographies of akermanite ceramics on bioactivity in vitro, akermanite ceramics were synthesized by sol-gel method and different surface topographies of disc-shaped akermanite ceramics were prepared by polishing with different SiC sandpapers. Atomic force microscopy (AFM) was used to evaluate the surface morphology and roughness. The bioactivity in vitro of ceramics with different surface states was evaluated by soaking the ceramics in simulated body fluid (SBF). And the samples after being soaked were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectrometry (EDS). The results showed that the amounts of precipitated apatite on the ceramics with different surface roughness after being soaked in SBF were different and the bioactivity in vitro of ceramic with rough surface was significantly higher than that of ceramic with smooth surface. The study suggested that suitable surface roughness may improve the bioactivity in vitro of akermanite ceramics.

Sphingoid bases and the serine catabolic enzyme CHA1 define a novel feedforward/feedback mechanism in the response to serine availability.

Science.gov (United States)

Montefusco, David J; Newcomb, Benjamin; Gandy, Jason L; Brice, Sarah E; Matmati, Nabil; Cowart, L Ashley; Hannun, Yusuf A

2012-03-16

Targets of bioactive sphingolipids in Saccharomyces cerevisiae were previously identified using microarray experiments focused on sphingolipid-dependent responses to heat stress. One of these heat-induced genes is the serine deamidase/dehydratase Cha1 known to be regulated by increased serine availability. This study investigated the hypothesis that sphingolipids may mediate the induction of Cha1 in response to serine availability. The results showed that inhibition of de novo synthesis of sphingolipids, pharmacologically or genetically, prevented the induction of Cha1 in response to increased serine availability. Additional studies implicated the sphingoid bases phytosphingosine and dihydrosphingosine as the likely mediators of Cha1 up-regulation. The yeast protein kinases Pkh1 and Pkh2, known sphingoid base effectors, were found to mediate CHA1 up-regulation via the transcription factor Cha4. Because the results disclosed a role for sphingolipids in negative feedback regulation of serine metabolism, we investigated the effects of disrupting this mechanism on sphingolipid levels and on cell growth. Intriguingly, exposure of the cha1Δ strain to high serine resulted in hyperaccumulation of endogenous serine and in turn a significant accumulation of sphingoid bases and ceramides. Under these conditions, the cha1Δ strain displayed a significant growth defect that was sphingolipid-dependent. Together, this work reveals a feedforward/feedback loop whereby the sphingoid bases serve as sensors of serine availability and mediate up-regulation of Cha1 in response to serine availability, which in turn regulates sphingolipid levels by limiting serine accumulation.

Crystallinity and compositional changes in carbonated apatites: Evidence from 31P solid-state NMR, Raman, and AFM analysis

Science.gov (United States)

McElderry, John-David P.; Zhu, Peizhi; Mroue, Kamal H.; Xu, Jiadi; Pavan, Barbara; Fang, Ming; Zhao, Guisheng; McNerny, Erin; Kohn, David H.; Franceschi, Renny T.; Holl, Mark M. Banaszak; Tecklenburg, Mary M. J.; Ramamoorthy, Ayyalusamy; Morris, Michael D.

2013-10-01

Solid-state (magic-angle spinning) NMR spectroscopy is a useful tool for obtaining structural information on bone organic and mineral components and synthetic model minerals at the atomic-level. Raman and 31P NMR spectral parameters were investigated in a series of synthetic B-type carbonated apatites (CAps). Inverse 31P NMR linewidth and inverse Raman PO43-ν1 bandwidth were both correlated with powder XRD c-axis crystallinity over the 0.3-10.3 wt% CO32- range investigated. Comparison with bone powder crystallinities showed agreement with values predicted by NMR and Raman calibration curves. Carbonate content was divided into two domains by the 31P NMR chemical shift frequency and the Raman phosphate ν1 band position. These parameters remain stable except for an abrupt transition at 6.5 wt% carbonate, a composition which corresponds to an average of one carbonate per unit cell. This near-binary distribution of spectroscopic properties was also found in AFM-measured particle sizes and Ca/P molar ratios by elemental analysis. We propose that this transition differentiates between two charge-balancing ion-loss mechanisms as measured by Ca/P ratios. These results define a criterion for spectroscopic characterization of B-type carbonate substitution in apatitic minerals.

Determination of palaeotemperatures of apatite with the fission-track method

International Nuclear Information System (INIS)

Bertagnolli, E.; Maerk, E.; Bertel, E.; Pahl, M.; Maerk, T.D.

1981-01-01

As a consequence of thermal fading of fission tracks in minerals, the fission-track dating method can be used to obtain a sensitive geothermometer for unfolding thermal events in the history of rocks, especially if it is possible to determine the temperature associated with a measured fission-track age, i.e., yielding a temperature age. Based on the concept of a minimum fission-track length the differential annealing equation has been solved for apatite, taking into account the fact that the annealing coefficient depends also on the degree of fission-track reduction. This allows us to calculate an improved age-temperature relationship for apatite, which gives for a measured corrected fission-track age the corresponding temperature, assuming either linear or exponential time-dependence of the temperature. The present results for apatite are compared with previous calculations in apatite and sphene. As expected, a fission-track age of apatite dates a younger (lower temperature) point in the thermal-cooling history than a fission-track age of sphene. (author)

δ18O of apatite phosphate in small pelagic fish: insights from wild-caught and tank-grown specimens

Science.gov (United States)

Lambert, T.; Javor, B.; Paytan, A.

2011-12-01

Oxygen isotope ratios of mineralized structures in fish reflect the temperature and isotopic composition of the water in which they grow. For bulk samples (e.g., whole scales, bones, and otoliths), understanding how this signal is integrated across time and space is critical, especially for organisms exposed to high variability in growth conditions. Here, we assess the response of fish scale δ18O (from apatite phosphate) to experimentally manipulated water conditions. Wild-caught sardines were grown at controlled temperatures (13°C, 17°C, and 21°C) for 11 months. Higher growth temperatures correlated to lower δ18O values, representing a combination of scale apatite deposited before and after the temperature manipulation. Models that account for both biomineral allometry and exposure to varying water properties (e.g., by overlaying migration routes, isoscapes, and temperature maps) have the potential to quantify the varying contributions of minerals grown under different conditions. We use this method to predict δ18O of apatite phosphate for small pelagic fish found in California coastal waters, then compare expected values to those obtained from collected samples. Since phosphate oxygen is relatively resistant to diagenesis, this modern calibration establishes a framework for paleo studies.

Interaction between the Bacterium Pseudomonas fluorescens strain CHA0, its genetic derivatives and vermiculite: Effects on chemical, mineralogical and mechanical properties of vermiculite

Science.gov (United States)

Mueller, Barbara

2016-04-01

Using bacteria of the strain Pseudomonas fluorescens wild type CHA0 and its genetic derivative strains CHA77, CHA89, CHA400, CHA631 and CHA661 (which differ in one gene only) the changes in chemical, mineralogical and rheological properties of the clay mineral vermiculite affected by microbial activity were studied in order to test whether the individually different production of metabolites by the genetically engineered strains may alter the clay mineral vermiculite in distinct ways. With the novel strategy of working with living wild type bacteria, their genetic derivatives and clay, the following properties of the mineral altered by the various strains of Pseudomonas fluorescens were determined: grain size, X-Ray diffraction pattern, intercrystalline swelling with glycerol, layer charge, CEC, BET surface and uptake of trace elements. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to determine the changes in major, minor and trace elements of the clay vermiculite affected by microbial activity. Among all analyzed trace elements, Fe, Mn and Cu are the most interesting. Fe and Mn are taken up from the clay mineral by all bacterial strains whereas Cu is only removed from vermiculite by strains CHA0, CHA77, CHA400 and CHA661. The latter mentioned strains all produce the antibiotics 2,4-diacetylphloroglucinol and monoacetylphloroglucinol which can complex Cu efficiently. Therefore the alteration of only one gene of the bacteria is causing significant effects on the clay mineral.

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

Evaluation of four biodegradable, injectable bone cements in an experimental drill hole model in sheep.

Science.gov (United States)

von Rechenberg, Brigitte; Génot, Oliver R; Nuss, Katja; Galuppo, Larry; Fulmer, Mark; Jacobson, Evan; Kronen, Peter; Zlinszky, Kati; Auer, Jörg A

2013-09-01

Four cement applications were tested in this investigation. Two dicalcium phosphate dihydrate (DCPD-brushite) hydraulic cements, an apatite hydraulic fiber loaded cement, and a calcium sulfate cement (Plaster of Paris) were implanted in epiphyseal and metaphyseal cylindrical bone defects in sheep. The in vivo study was performed to assess the biocompatibility and bone remodeling of four cement formulations. After time periods of 2, 4, and 6 months, the cement samples were clinically and histologically evaluated. Histomorphometrically, the amount of new bone formation, fibrous tissue, and bone marrow and the area of remaining cement were measured. In all specimens, no signs of inflammation were detectable either macroscopically or microscopically. Cements differed mainly in their resorption time. Calcium sulfate was already completely resorbed at 2 months and showed a variable amount of new bone formation and/or fibrous tissue in the original drill hole over all time periods. The two DCPD cements in contrast were degraded to a large amount at 6 months, whereas the apatite was almost unchanged over all time periods. Copyright © 2013. Published by Elsevier B.V.

Effect of radiation damage on the infrared properties of apatite

International Nuclear Information System (INIS)

Anis Faridah Md Nori; Yusof Mohd Amin; Rosli Mahat; Burhanuddin Kamaluddin

1991-01-01

Apatites are known to contain radioactive elements such as uranium and thorium at a few ppm in concentration. These elements decay and produce fission tracks inside the crystals. The presence of such tracks have been known to affect the thermoluminescence (TL) properties of apatites. These fission tracks can be removed by annealing the crystals in air. In this paper we present the result of a preliminary study on the effect of radiation damage on the infrared transmission of apatites

Polyelectrolyte multi-layers assembly of SiCHA nanopowders and collagen type I on aminolysed PLA films to enhance cell-material interactions.

Science.gov (United States)

Baba Ismail, Yanny Marliana; Ferreira, Ana Marina; Bretcanu, Oana; Dalgarno, Kenneth; El Haj, Alicia J

2017-11-01

This paper presents a new approach in assembling bone extracellular matrix components onto PLA films, and investigates the most favourable environment which can be created using the technique for cell-material interactions. Poly (lactic acid) (PLA) films were chemically modified by covalently binding the poly(ethylene imine) (PEI) as to prepare the substrate for immobilization of polyelectrolyte multilayers (PEMs) coating. Negatively charged polyelectrolyte consists of well-dispersed silicon-carbonated hydroxyapatite (SiCHA) nanopowders in hyaluronic acid (Hya) was deposited onto the modified PLA films followed by SiCHA in collagen type I as the positively charged polyelectrolyte. The outermost layer was finally cross-linked by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrocholoride and N-hydroxysulfosuccinimide sodium salt (EDC/NHS) solutions. The physicochemical features of the coated PLA films were monitored via X-ray Photoelectron Spectroscopy (XPS) and Atomic Force Microscope (AFM). The amounts of calcium and collagen deposited on the surface were qualitatively and quantitatively determined. The surface characterizations suggested that 5-BL has the optimum surface roughness and highest amounts of calcium and collagen depositions among tested films. In vitro human mesenchymal stem cells (hMSCs) cultured on the coated PLA films confirmed that the coating materials greatly improved cell attachment and survival compared to unmodified PLA films. The cell viability, cell proliferation and Alkaline Phosphatase (ALP) expression on 5-BL were found to be the most favourable of the tested films. Hence, this newly developed coating materials assembly could contribute to the improvement of the bioactivity of polymeric materials and structures aimed to bone tissue engineering applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Identification of Cha o 3 homolog Cry j 4 from Cryptomeria japonica (Japanese cedar) pollen: Limitation of the present Japanese cedar-specific ASIT.

Science.gov (United States)

Osada, Toshihiro; Tanaka, Yuki; Yamada, Akira; Sasaki, Eiji; Utsugi, Teruhiro

2018-03-07

About one-third of the Japanese population suffers from Japanese cedar pollinosis, which is frequently accompanied by Japanese cypress pollinosis. Recently, a novel major Japanese cypress pollen allergen, Cha o 3, was discovered. However, whether a Cha o 3 homolog is present in Japanese cedar pollen remains to be determined. Western blot analysis was performed using Cha o 3-specific antiserum. In addition, cloning of the gene encoding Cry j 4 was conducted using total cDNA from the male flower of Japanese cedar trees. Allergen potency and cross-reactivity were investigated using a T-cell proliferation assay, basophil activation test, and ImmunoCAP inhibition assay. A low amount of Cha o 3 homolog protein was detected in Japanese cedar pollen extract. The deduced amino acid sequence of Cry j 4 showed 84% identity to that of Cha o 3. Cross-reactivity between Cry j 4 and Cha o 3 was observed at the T cell and IgE levels. Cry j 4 was discovered as a counterpart allergen of Cha o 3 in Japanese cedar pollen, with a relationship similar to that between Cry j 1-Cha o 1 and Cry j 2-Cha o 2. Our findings also suggest that allergen-specific immunotherapy (ASIT) using Japanese cedar pollen extract does not induce adequate immune tolerance to Cha o 3 due to the low amount of Cry j 4 in Japanese cedar pollen. Therefore, ASIT using Cha o 3 or cypress pollen extract coupled with Japanese cedar pollen extract is required in order to optimally control allergy symptoms during Japanese cypress pollen season. Copyright © 2018 Japanese Society of Allergology. Production and hosting by Elsevier B.V. All rights reserved.

Rare earth elements materials production from apatite ores

International Nuclear Information System (INIS)

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

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. (paper)

Physiochemical characterizations of hydroxyapatite extracted from bovine bones by three different methods: Extraction of biologically desirable HAp

International Nuclear Information System (INIS)

Barakat, Nasser A.M.; Khalil, K.A.; Sheikh, Faheem A.; Omran, A.M.; Gaihre, Babita; Khil, Soeb M.; Kim, Hak Yong

2008-01-01

In the present study, subcritical water and alkaline hydrolysis methods are proposed methodologies for extraction of natural hydroxyapatite bioceramic from bovine bone. In these processes, the bovine bones powder were treated by high pressure water at 250 deg. C for 1 h and 25% (wt) sodium hydroxide at 250 deg. C for 5 h, respectively. Also the conventional calcination methodology has been utilized as well (T = 850 deg. C for 1 h). The obtained apatites from the three treatment processes have been characterized by powder X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT IR), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), electron scanning microscopy (SEM), energy dispersive X-ray analysis (EDX) and field emission scanning electron microscopy (FE SEM). FT IR and XRD results affirmed that both the proposed methods and the traditional one can eliminate the collagen and other organic materials present in the bovine bones. The physiochemical characterizations for the obtained apatites have proved that the subcritical water and the alkaline hydrolysis relatively preserve the carbonate content present in the biological apatite, so they yield carbonated hydroxyapatite which is medically preferable. While, the thermal process produces almost hydroxyapatite carbonate-free

Differential impact of some Aspergillus species on Meloidogyne javanica biocontrol by Pseudomonas fluorescens strain CHA0.

Science.gov (United States)

Siddiqui, I A; Shaukat, S S; Khan, A

2004-01-01

The aim was to determine the influence of some Aspergillus species on the production of nematicidal agent(s) in vitro and biocontrol of Meloidogyne javanica in tomato by Pseudomonas fluorescens strains CHA0 and CHA0/pME3424. Six species of Aspergillus, isolated from the rhizosphere of certain crops, produced a variety of secondary metabolites in vitro. Culture filtrate (CF) obtained from Ps. fluorescens strain CHA0 and its2,4-diacetylphloroglucinol overproducing mutant CHA0/pME3424 grown in King's B liquid medium caused significant mortality of M. javanica juveniles in vitro. Bacterial growth medium amended with CF of A. niger enhanced nematicidal and beta-galactosidase activities of fluorescent pseudomonads while A. quadrilineatus repressed such activities. Methanol or ethyl acetate extracts of the CF of A. niger markedly optimized bacterial efficacy to cause nematode deaths while hexane extract of the fungus had no influence on the nematicidal activity of the bacterial strains. A. niger applied alone or in conjunction with the bacterial inoculants inhibited root-knot nematode galling in tomato. On the other hand, A. quadrilineatus used alone or together with CHA0 did not inhibit nematode galling but when used in combination with strain CHA0/pME3424 did reduce galling intensity. Aspergillus niger enhances the production of nematicidal compounds by Ps. fluorescensin vitro and improves biocontrol potential of the bacterial inoculants in tomato while A. quadrilineatus reduces bacterial performance to suppress root-knot nematodes. Rhizosphere harbours a variety of micro-organisms including bacteria, fungi and viruses. Aspergillus species are ubiquitous in most agricultural soils and generally produce a variety of secondary metabolites. Such metabolites synthesized by Aspergillus species may influence the production of nematicidal agents and subsequent biocontrol performance of the bacterial inoculants against plant-parasitic nematodes. This fact needs to be taken into

Coordination Environment of Copper Sites in Cu-CHA Zeolite Investigated by Electron Paramagnetic Resonance

DEFF Research Database (Denmark)

Godiksen, Anita; Stappen, Frederick N.; Vennestrøm, Peter N. R.

2014-01-01

Cu-CHA combines high activity for the selective catalytic reduction (SCR) reaction with better hydrothermal stability and selectivity compared to other copper-substituted zeolites. At the same time Cu-CHA offers an opportunity for unraveling the coordination environment of the copper centers since...... the zeolite framework is very simple with only one crystallographically independent tetrahedral site (T-site). In this study the results of an X-band electron paramagnetic resonance (EPR) investigation of ion-exchanged Cu-CHA zeolite with a Si/Al ratio of 14 ± 1 is presented. Different dehydration treatments...... of the EPR silent monomeric Cu2+ in copper-substituted zeolites is suggested to be copper species with an approximate trigonal coordination sphere appearing during the dehydration. After complete dehydration at 250 °C the majority of the EPR silent Cu2+ is suggested to exist as Cu2+–OH– coordinated to two...

Calcium carbonate-calcium phosphate mixed cement compositions for bone reconstruction.

Science.gov (United States)

Combes, C; Bareille, R; Rey, C

2006-11-01

The feasibility of making calcium carbonate-calcium phosphate (CaCO(3)-CaP) mixed cements, comprising at least 40% (w/w) CaCO(3) in the dry powder ingredients, has been demonstrated. Several original cement compositions were obtained by mixing metastable crystalline CaCO(3) phases with metastable amorphous or crystalline CaP powders in aqueous medium. The cements set within at most 1 h at 37 degrees C in atmosphere saturated with water. The hardened cement is microporous and exhibits weak compressive strength. The setting reaction appeared to be essentially related to the formation of a highly carbonated nanocrystalline apatite phase by reaction of the metastable CaP phase with part or almost all of the metastable CaCO(3) phase. The recrystallization of metastable CaP varieties led to a final cement consisting of a highly carbonated poorly crystalline apatite analogous to bone mineral associated with various amounts of vaterite and/or aragonite. The presence of controlled amounts of CaCO(3) with a higher solubility than that of the apatite formed in the well-developed CaP cements might be of interest to increase resorption rates in biomedical cement and favors its replacement by bone tissue. Cytotoxicity testing revealed excellent cytocompatibility of CaCO(3)-CaP mixed cement compositions.

Study of tissue engineered bone nodules by Fourier transform infrared spectroscopy.

Science.gov (United States)

Aydin, Halil Murat; Hu, Bin; Suso, Josep Sulé; El Haj, Alicia; Yang, Ying

2011-02-21

The key criteria for assessing the success of bone tissue engineering are the quality and quantity of the produced minerals within the cultured constructs. The accumulation of calcium ions and inorganic phosphates in culture medium serves as nucleating agents for the formation of hydroxyapatite, which is the main inorganic component of bone. Bone nodule formation is one of the hallmarks of mineralization in such cell cultures. In this study, we developed a new two-step procedure to accelerate bone formation in which mouse bone cell aggregates were produced first on various chemically treated non-adhesive substrates. After this step, the bone cells' growth and mineralization were followed in conventional culture plates. The number and size of cell aggregates were studied with light microscopy. The minerals' formation in the form of nodules produced by the cell aggregates and the bone crystal quality were studied with Fourier Transform Infrared (FTIR) spectroscopy. The FTIR spectra of the ash specimens (mineral phase only) from thermal gravimetric analysis (TGA) provided valuable information of the quality of the minerals. The υ(4) PO(4) region (550-650 cm(-1)), which reveals apatitic and non-apatitic HPO(4) or PO(4) environments, and phosphate region (910-1180 cm(-1)) were examined for the minerals produced in the form of nodules. The peak position and intensity of the spectra demonstrate that the quality of the bone produced by cell aggregates, especially from the bigger ones, which were formed on Plunoric treated substrates, exhibit a composition more similar to that of native bone. This work establishes a new protocol for high quality bone formation and characterization, with the potential to be applied to bone tissue engineering.

Effects of diagenesis on strontium, carbon, nitrogen and oxygen concentration and isotopic composition of bone

Science.gov (United States)

Nelson, Bruce K.; Deniro, Michael J.; Schoeninger, Margaret J.; De Paolo, Donald J.; Hare, P. E.

1986-09-01

Paleodietary analysis based on variations in the trace element and stable isotopic composition of inorganic and organic phases in fossil bone depends on the assumption that measured values reflect in vivo values. To test for postmortem alteration, we measured 87Sr /86Sr , 13C /12C , 18O /16O and 15N /14N ratios and Sr concentrations in modern and prehistoric (610 to 5470 yr old) bones of animals with marine or terrestrial diets from Greenland. Bones from modern terrestrial feeders have substantially lower Sr concentrations and more radiogenic 87Sr /86Sr ratios than those from modern marine feeders. This contrast was not preserved in the prehistoric samples, which showed almost complete overlap for both Sr concentration and isotopic composition in bones from the two types of animals. Leaching experiments, X-ray diffraction analysis and infrared spectroscopy indicate that alteration of the Sr concentration and isotopic composition in prehistoric bone probably results from nearly complete exchange with groundwater. Oxygen isotope ratios in fossil apatite carbonate also failed to preserve the original discrimination between modern terrestrial and marine feeders. The C isotope ratio of apatite carbonate did not discriminate between animals with marine or terrestrial diets in the modern samples. Even so, the ranges of apatite δ 13C values in prehistoric bone are more scattered than in modern samples for both groups, suggesting alteration had occurred. δ 13C and δ 15N values of collagen in modern bone are distinctly different for the two feeding types, and this distinction is preserved in most of the prehistoric samples. Our results suggest that postmortem alteration of dietary tracers in the inorganic phases of bone may be a problem at all archaeological sites and must be evaluated in each case. While collagen analyzed in this study was resistant to alteration, evaluation of the possibility of diagenetic alteration of its isotopic composition in bones from other

Fabrication of highly porous biodegradable biomimetic nanocomposite as advanced bone tissue scaffold

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Abdalla Abdal-hay

2017-02-01

Full Text Available Development of bioinspired or biomimetic materials is currently a challenge in the field of tissue regeneration. In-situ 3D biomimetic microporous nanocomposite scaffold has been developed using a simple lyophilization post hydrothermal reaction for bone healing applications. The fabricated 3D porous scaffold possesses advantages of good bonelike apatite particles distribution, thermal properties and high porous interconnected network structure. High dispersion bonelike apatite nanoparticles (NPs rapidly nucleated and deposited from surrounding biological minerals within chitosan (CTS matrices using hydrothermal technique. After that, freeze-drying method was applied on the composite solution to form the desired porous 3D architecture. Interestingly, the porosity and pore size of composite scaffold were not significantly affected by the particles size and particles content within the CTS matrix. Our results demonstrated that the compression modulus of porous composite scaffold is twice higher than that of plain CTS scaffold, indicating a maximization of the chemical interaction between polymer matrix and apatite NPs. Cytocompatibility test for MC3T3-E1 pre-osteoblasts cell line using MTT-indirect assay test showed that the fabricated 3D microporous nanocomposite scaffold possesses higher cell proliferation and growth than that of pure CTS scaffold. Collectively, our results suggest that the newly developed highly porous apatite/CTS nanocomposite scaffold as an alternative of hydroxyapatite/CTS scaffold may serve as an excellent porous 3D platform for bone tissue regeneration.

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

International Nuclear Information System (INIS)

Chatelain, Grégory; Bourgeois, Damien; Meyer, Daniel; Ravaux, Johann; Averseng, Olivier; Vidaud, Claude

2014-01-01

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)

Understanding the evolution of S- and I-type granitic plutons through analysis of apatite.

Science.gov (United States)

Hess, B. L.; Fiege, A.; Tailby, N.

2017-12-01

The major and trace element composition of apatites from the Lachlan fold belt (LFB) S- and I-type granitoids (Australia) and the Central French Massif (CFM) S-type leucogranites (France) were analyzed to investigate their compositional and redox variation. Apatite is a common accessory mineral in magmatic systems that can incorporate a variety of trace elements, including the polyvalent elements sulfur (S), iron (Fe), and manganese (Mn). It was recently discovered that apatite can incorporate three oxidation states of S (S6+, S4+, S2-) into its structure as a function of oxygen fugacity [1]. However, the oxidation states of Mn and Fe in apatite are essentially unknown (2+ and/or 3+). In this study, we collected many electron probe line transects across apatites in several different host phases from a variety of S- and I-type plutons. The F-H-Cl contents of the S- and I-type LFB samples were similar ( 2.9 wt% F, 0.4 wt% Cl, 0.5 wt% OH). The CFM S-types contained virtually no Cl and ranged from near-endmember OH-apatite to near-endmember F-apatite. The apatites of all studied the S- and I-type plutons are characterized by similar ranges of Fe content (X-ray absorption near-edge structure (XANES) spectroscopy. The spectra show variability in S oxidation states ranging from mostly sulfate down to nearly equal S6+/S2- ratios, indicating redox variations during apatite formation. The S-type Mn + Fe content plots in a 1:1 ratio against calcium (Ca) in atoms per formula unit, while the I-type apatites have too low Mn and Fe to show a clear trend. Thus, divalent Mn and Fe probably replace Ca2+ in the S-types' apatite structure, while the incorporation of trivalent Mn or Fe in apatite is rather unlikely. We suggest that Mn and Fe contents in apatite may become a useful tracer of melt evolution once the distributions coefficients are experimentally calibrated. [1] Konecke et al. (2017), Am Mineral

Bioactive Glass Nanopowder for theTreatment of Oral Bone Defects

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MH. Fathi

2007-09-01

Full Text Available Objective: Osseous defects around dental implants are often seen when implants are placed in areas with inadequate alveolar bone, or around failing implants. Bone regenera-tion in these areas using bone grafts or its substitutes may improve dental implants prog-nosis. The aim of this study was to prepare and characterize the bioactive glass nanopow-der and development of its coating for treatment of oral bone defects.Materials and Methods: Bioactive bioglass coating was made on stainless steel plates by sol-gel technique. The powder shape and size was evaluated by transmission electron mi-cropscopy, and thermal properties studied using differential thermal analysis (DTA. Structural characterization techniques (XRD were used to analyze and study the structure and phase present in the prepared bioactive glass nanopowder. This nanopowder was immersed in the simulated body fluid (SBF solution. Fourier transform infrared spec-troscopy (FTIR was utilized to recognize and confirm the formation of apatite layer on prepared bioactive glass nanopowder.Results: The bioglass powder size was less than 100 nanometers which was necessary for better bioactivity, and preparing a homogeneous coating. The formation of apatite layer confirmed the bioactivity of the bioglass nanopowder. Crack-free and homogeneous bioglass coatings were achieved with no observable defects.Conclusion: It was concluded that the prepared bioactive glass nanopowder could be more effective as a bone replacement material than conventional bioactive glass to pro-mote bone formation in osseous defects. The prepared bioactive glass nanopowder could be more useful for treatment of oral bone defects compare to conventional hydroxyapatite or bioactive glass.

Calcium phosphate nuclear materials: apatitic ceramics for separated wastes

International Nuclear Information System (INIS)

Carpena, J.; Lacout, J.L.

2005-01-01

Is it feasible to elaborate conditioning materials for separated high activity nuclear wastes, as actinides or fission products? Specific materials have been elaborated so that the waste is incorporated within the crystalline structure of the most stable calcium phosphate, i.e. apatite. This mineral is able to sustain high irradiation doses assuming a well chosen chemical composition. Mainly two different ways of synthesis have been developed to produce hard apatite ceramics that can be used to condition nuclear wastes. Here we present a data synthesis regarding the elaboration of these apatite nuclear materials that includes experiments on crystallo-chemistry, chemical analysis, leaching and irradiation tests performed for the past fifteen years. (authors)

Lead Speciation and Bioavailability in Apatite-Amended Sediments

Directory of Open Access Journals (Sweden)

Kirk G. Scheckel

2011-01-01

Full Text Available The in situ sequestration of lead (Pb in sediment with a phosphate amendment was investigated by Pb speciation and bioavailability. Sediment Pb in preamendment samples was identified as galena (PbS with trace amounts of absorbed Pb. Sediment exposed to atmospheric conditions underwent conversion to hydrocerussite and anglesite. Sediments mixed with apatite exhibited limited conversion to pyromorphite, the hypothesized end product. Conversion of PbS to pyromorphite is inhibited under reducing conditions, and pyromorphite formation appears limited to reaction with pore water Pb and PbS oxidation products. Porewater Pb values were decreased by 94% or more when sediment was amended with apatite. The acute toxicity of the sediment Pb was evaluated with Hyalella azteca and bioaccumulation of Pb with Lumbriculus variegatus. The growth of H. azteca may be mildly inhibited in contaminated sediment, with apatite-amended sediments exhibiting on average a higher growth weight by approximately 20%. The bioaccumulation of Pb in L. variegatus tissue decreased with increased phosphate loading in contaminated sediment. The study indicates limited effectiveness of apatite in sequestering Pb if present as PbS under reducing conditions, but sequestration of porewater Pb and stabilization of near-surface sediment may be a feasible and alternative approach to decreasing potential toxicity of Pb.

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

2016-05-01

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.

Mg substituted apatite coating from alkali conversion of acidic calcium phosphate

Energy Technology Data Exchange (ETDEWEB)

Navarro da Rocha, Daniel, E-mail: dnr.navarro@gmail.com [Military Institute of Engineering-IME, Pça. Gen. Tiburcio, 80, P. Vermelha, Urca, Rio de Janeiro, R.J. (Brazil); Cruz, Leila Rosa de Oliveira [Military Institute of Engineering-IME, Pça. Gen. Tiburcio, 80, P. Vermelha, Urca, Rio de Janeiro, R.J. (Brazil); Campos, José Brant de [Rio de Janeiro State University - UERJ, Rio de Janeiro, R.J. (Brazil); Marçal, Rubens L. Santana Blazutti [Military Institute of Engineering-IME, Pça. Gen. Tiburcio, 80, P. Vermelha, Urca, Rio de Janeiro, R.J. (Brazil); Mijares, Dindo Q.; Coelho, Paulo G. [Department of Biomaterials and Biomimetics, New York University College of Dentistry (NYU), New York, NY (United States); Prado da Silva, Marcelo H. [Military Institute of Engineering-IME, Pça. Gen. Tiburcio, 80, P. Vermelha, Urca, Rio de Janeiro, R.J. (Brazil)

2017-01-01

In this work, two solutions were developed: the first, rich in Ca{sup 2+}, PO{sub 4}{sup 3−} ions and the second, rich in Ca{sup 2+}, PO{sub 4}{sup 3−} and Mg{sup 2+}, defined as Mg-modified precursor solution. For each Mg-modified precursor solution, the concentrations of Mg{sup 2+} ions were progressively increased by 5%, 10% and 15%wt. The aims of this research were to investigate the influence of magnesium ions substitution in calcium phosphate coatings on titanium surface and to evaluate these coatings by bioactivity assay in McCoy culture medium. The obtained coatings were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis, and the presence of Mg ions was confirmed by the inductively coupled plasma atomic emission spectroscopy (ICP) analysis. In vitro bioactivity assay in McCoy culture medium showed bioactivity after 14 days in incubation for the HA and 10% Mg-monetite coatings. The high chemical stability of Mg-HA coatings was verified by the bioactivity assays, and no bone-like apatite deposition, characteristic of bioactivity, was observed for Mg-HA coatings, for the time period used in this study. - Highlights: • The presence of Mg ions influenced the final apatite phase present in the produced coatings. • A lower efficiency in heterogeneous deposition and an exposure of Ti substrate in 5% Mg-monetite coatings was soon verified. • McCoy culture medium was effective in predicting the coatings bioactivity.

Certain distribution characteristics of uranium and thorium in apatite-carbonate ores

Energy Technology Data Exchange (ETDEWEB)

Kharitonova, R Sh; Faizullin, R N; Kozlov, E N; Berman, I B

1979-01-01

A study of the total radioactivity, uranium content, thorium content, U/Th ratio, and the spatial distribution of uranium by the f-radiographic method has demonstrated that the apatite ores of the deposit contain elevated concentrations of radioactive elements that are essentially of thorium origin. The main concentration of uranium and thorium is in the cinnemon-brown apatite. Elevated uranium concentrations are also found in hematite and accessory minerals (monacite, zirconium, titanite). Dolomite, quartz, martite, and second generation apatite were found to be weakly radioactive. The uranium and thorium concentration is correlated to the concentration of phosphorus and other petrogenic elements. An analysis of uranium, thorium, and Th/U distribution indicates that the concentration of radioactive elements is not caused by their primary content in carbonate rock but by the outside introduction of these elements together with phosphorus. The cited analyses confirm the chemogenic-sedimentary origin of the dolomite substrate and the metamorphogenic hydrothermal genesis of apatite mineralization. The data on radioactivity may be used as a reliable exploratory criterion for apatite potential. 3 references, 3 figures.

Amelogenin as a promoter of nucleation and crystal growth of apatite

Science.gov (United States)

Uskoković, Vuk; Li, Wu; Habelitz, Stefan

2011-02-01

Human dental enamel forms over a period of 2-4 years by substituting the enamel matrix, a protein gel mostly composed of a single protein, amelogenin with fibrous apatite nanocrystals. Self-assembly of amelogenin and the products of its selective proteolytic digestion are presumed to direct the growth of apatite fibers and their organization into bundles that eventually comprise the mature enamel, the hardest tissue in the mammalian body. This work aimed to establish the physicochemical and biochemical conditions for the growth of apatite crystals under the control of a recombinant amelogenin matrix (rH174) in combination with a programmable titration system. The growth of apatite substrates was initiated in the presence of self-assembling amelogenin particles. A series of constant titration rate experiments was performed that allowed for a gradual increase of the calcium and/or phosphate concentrations in the protein suspensions. We observed a significant amount of apatite crystals formed on the substrates following the titration of rH174 sols that comprised the initial supersaturation ratio equal to zero. The protein layers adsorbed onto the substrate apatite crystals were shown to act as promoters of nucleation and growth of calcium phosphates subsequently formed on the substrate surface. Nucleation lag time experiments have showed that rH174 tends to accelerate precipitation from metastable calcium phosphate solutions in proportion to its concentration. Despite their mainly hydrophobic nature, amelogenin nanospheres, the size and surface charge properties of which were analyzed using dynamic light scattering, acted as a nucleating agent for the crystallization of apatite. The biomimetic experimental setting applied in this study proves as convenient for gaining insight into the fundamental nature of the process of amelogenesis.

Predictive Value of CHA2DS2-VASC Score for Contrast-Induced Nephropathy After Percutaneous Coronary Intervention for Acute Coronary Syndrome.

Science.gov (United States)

Kurtul, Alparslan; Yarlioglues, Mikail; Duran, Mustafa

2017-03-15

The CHA2DS2-VASC score, used for embolic risk stratification in atrial fibrillation (AF), has been reported recently to predict adverse clinical outcomes in patients with acute coronary syndrome (ACS), regardless of having AF. We investigated the correlation between the CHA2DS2-VASC score and contrast-induced nephropathy (CIN) in patients with ACS who underwent urgent percutaneous coronary intervention (PCI). A total of 1,408 patients were enrolled in the study. The CHA2DS2-VASC score was calculated for each patient. Based on the receiver operating characteristic analysis, the study population was divided into 2 groups: CHA2DS2-VASC score ≤3 group (n = 944) and CHA2DS2-VASC score ≥4 group (n = 464). Patients were then reallocated to 2 groups according to the presence or absence of CIN. CIN was defined as a rise in serum creatinine >0.5 mg/dl or >25% increase in baseline within 72 hours after PCI. Overall, 159 cases (11.3%) of CIN were diagnosed. Receiver operating characteristic curve analysis revealed good diagnostic value of CHA2DS2-VASC score in predicting CIN (area under the curve 0.769, 95% confidence interval 0.733 to 0.805; p high score had a higher frequency of CIN (23.9% vs 5.1%; p <0.001), and multivariate analysis identified the CHA2DS2-VASC score of ≥4 as an independent predictor of CIN. In conclusion, CHA2DS2-VASC score can be used as a new, simple, and reliable tool to predict CIN in patients with ACS who underwent urgent PCI. Copyright © 2016 Elsevier Inc. All rights reserved.

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

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

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

Effect of Alkali-Acid-Heat Chemical Surface Treatment on Electron Beam Melted Porous Titanium and Its Apatite Forming Ability.

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Bsat, Suzan; Yavari, Saber Amin; Munsch, Maximilian; Valstar, Edward R; Zadpoor, Amir A

2015-04-08

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.

Effect of Alkali-Acid-Heat Chemical Surface Treatment on Electron Beam Melted Porous Titanium and Its Apatite Forming Ability

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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.

Hydrophobic agglomeration of apatite fines induced by sodium oleate in aqueous solutions

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Bingqiao Yang

2018-06-01

Full Text Available In this work, the hydrophobic agglomeration of apatite fines induced by sodium oleate in aqueous solutions has been investigated through the measurement of agglomeration degree and fractal dimension. The results showed that the agglomeration degree of apatite fines and agglomerates morphology was strongly depended on sodium oleate concentration, pH, stirring speed and time. Better agglomeration degree and more regular agglomerates were achieved at sodium oleate concentration of 5 × 10−5 mol/L under neutral condition. The critical stirring speed for agglomerates rupture was 1000 rev/min, above which, prolonged stirring time would cause breakage and restructure of the agglomerates after a certain stirring time, resulting in lower agglomeration degree and more regular agglomerates. The agglomeration degree of apatite fines could be greatly enhanced with the addition of emulsified kerosene, but only if the apatite surface was hydrophobic enough. Keywords: Hydrophobic agglomeration, Apatite fines, Agglomeration degree, Fractal dimension, Sodium oleate

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

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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

Porous surface modified bioactive bone cement for enhanced bone bonding.

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Qiang He

Full Text Available Polymethylmethacrylate bone cement cannot provide an adhesive chemical bonding to form a stable cement-bone interface. Bioactive bone cements show bone bonding ability, but their clinical application is limited because bone resorption is observed after implantation. Porous polymethylmethacrylate can be achieved with the addition of carboxymethylcellulose, alginate and gelatin microparticles to promote bone ingrowth, but the mechanical properties are too low to be used in orthopedic applications. Bone ingrowth into cement could decrease the possibility of bone resorption and promote the formation of a stable interface. However, scarce literature is reported on bioactive bone cements that allow bone ingrowth. In this paper, we reported a porous surface modified bioactive bone cement with desired mechanical properties, which could allow for bone ingrowth.The porous surface modified bioactive bone cement was evaluated to determine its handling characteristics, mechanical properties and behavior in a simulated body fluid. The in vitro cellular responses of the samples were also investigated in terms of cell attachment, proliferation, and osteoblastic differentiation. Furthermore, bone ingrowth was examined in a rabbit femoral condyle defect model by using micro-CT imaging and histological analysis. The strength of the implant-bone interface was also investigated by push-out tests.The modified bone cement with a low content of bioactive fillers resulted in proper handling characteristics and adequate mechanical properties, but slightly affected its bioactivity. Moreover, the degree of attachment, proliferation and osteogenic differentiation of preosteoblast cells was also increased. The results of the push-out test revealed that higher interfacial bonding strength was achieved with the modified bone cement because of the formation of the apatite layer and the osseointegration after implantation in the bony defect.Our findings suggested a new bioactive

Magnetite-apatite mineralization in Khanlogh iron deposit, northwest of Neyshaboor, NE Iran

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Najafzadeh Tehrani, Parvin; Asghar Calagari, Ali; Velasco Roldan, Francisco; Simmonds, Vartan; Siahcheshm, Kamal

2016-04-01

Khanlogh iron deposit lies on Sabzehvar-Ghoochan Cenozoic magmatic belt in northwest of Neyshaboor, NE Iran. The lithologic units in this area include a series of sub-volcanic intrusive rocks like diorite porphyry, quartz-diorite porphyry, and micro-granodiorite of Oligocene age. Mineralization in this area occurred as veins, dissemination, and open space filling in brecciated zones within the host sub-volcanic intrusive bodies. Three distinct types of mineral associations can be distinguished, (1) diopside-magnetite, (2) magnetite-apatite, and (3) apatite-calcite. Microscopic examinations along with SEM and EPMA studies demonstrated that magnetite is the most common ore mineral occurring as solitary crystals. The euhedral magnetite crystals are accompanied by lamellar destabilized ilmenite and granular fluorapatite in magnetite-apatite ores. The results of EPMA revealed that the lamellar ilmenite, relative to host magnetite crystal, is notably enriched in MgO and MnO (average of 3.3 and 2.6 wt%, respectively; n=5), whereas magnetite is slighter enriched in Ti (TiO2 around 1.8 wt%) being average of MgO, MnO and V2O3 of 0.6wt%, 0.2wt%, and 0.6 wt% (respectively; n=20). Minerals such as chlorapatite, calcite, and chalcedony are also present in the magnetite-apatite ores. The samples from apatite-calcite ores contain coarse crystals of apatite and rhomboedral calcite. The plot of the EPMA data of Khanlogh iron ore samples on diagram of TiO2-V2O5 (Hou et al, 2011) illustrated that the data points lies between the well-known Kiruna and El Laco (Chile) iron deposits. The magnetite crystals in the sub-volcanic host rocks were possibly formed by immiscible iron oxide fluids during magmatic stage. However, the magnetite and apatite existing in the veins and breccia zones may have developed by high temperature hydrothermal fluids. Studies done by Purtov and Kotelnikova (1993) proved that the proportion of Ti in magnetite is related to fluoride complex in the hydrothermal

The effects of strontium on bone mineral: A review on current knowledge and microanalytical approaches.

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Querido, William; Rossi, Andre L; Farina, Marcos

2016-01-01

The interest in effects of strontium (Sr) on bone has greatly increased in the last decade due to the development of the promising drug strontium ranelate. This drug is used for treating osteoporosis, a major bone disease affecting hundreds of millions of people worldwide, especially postmenopausal women. The novelty of strontium ranelate compared to other treatments for osteoporosis is its unique effect on bone: it simultaneously promotes bone formation by osteoblasts and inhibits bone resorption by osteoclasts. Besides affecting bone cells, treatment with strontium ranelate also has a direct effect on the mineralized bone matrix. Due to the chemical similarities between Sr and Ca, a topic that has long been of particular interest is the incorporation of Sr into bones replacing Ca from the mineral phase, which is composed by carbonated hydroxyapatite nanocrystals. Several groups have analyzed the mineral produced during treatment; however, most analysis were done with relatively large samples containing numerous nanocrystals, resulting thus on data that represents an average of many crystalline domains. The nanoscale analysis of the bone apatite crystals containing Sr has only been described in a few studies. In this study, we review the current knowledge on the effects of Sr on bone mineral and discuss the methodological approaches that have been used in the field. In particular, we focus on the great potential that advanced microscopy and microanalytical techniques may have on the detailed analysis of the nanostructure and composition of bone apatite nanocrystals produced during treatment with strontium ranelate. Copyright © 2015. Published by Elsevier Ltd.

Liquid phase sintered ceramic bone scaffolds by combined laser and furnace.

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Feng, Pei; Deng, Youwen; Duan, Songlin; Gao, Chengde; Shuai, Cijun; Peng, Shuping

2014-08-21

Fabrication of mechanically competent bioactive scaffolds is a great challenge in bone tissue engineering. In this paper, β-tricalcium phosphate (β-TCP) scaffolds were successfully fabricated by selective laser sintering combined with furnace sintering. Bioglass 45S5 was introduced in the process as liquid phase in order to improve the mechanical and biological properties. The results showed that sintering of β-TCP with the bioglass revealed some features of liquid phase sintering. The optimum amount of 45S5 was 5 wt %. At this point, the scaffolds were densified without defects. The fracture toughness, compressive strength and stiffness were 1.67 MPam1/2, 21.32 MPa and 264.32 MPa, respectively. Bone like apatite layer was formed and the stimulation for apatite formation was increased with increase in 45S5 content after soaking in simulated body fluid, which indicated that 45S5 could improve the bioactivity. Furthermore, MG-63 cells adhered and spread well, and proliferated with increase in the culture time.

Changes in physicochemical and biological properties of porcine bone derived hydroxyapatite induced by the incorporation of fluoride

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Qiao, Wei; Liu, Quan; Li, Zhipeng; Zhang, Hanqing; Chen, Zhuofan

2017-12-01

As the main inorganic component of xenogenic bone graft material, bone-derived biological apatite (BAp) has been widely used in implant dentistry, oral and maxillofacial surgery and orthopedics. However, BAp produced via calcination of animal bones still suffers from some drawbacks, such as insufficient mechanical strength and inadequate degradation rate, which impede its application. Fluoride is known to play important roles in both physiological and pathological processes of human hard tissues for its double effects on bones and teeth. In order to understand the effects of fluoride on the properties of BAp, as well as the mechanism behind them, porcine bone derived hydroxyapatite (PHAp) was prepared via thermal treatment, which was then fluoride incorporated at a series concentrations of sodium fluoride, and noted as 0.25-FPHAp, 0.50-FPHAp, and 0.75-FPHAp respectively. The physicochemical characteristics of the materials, including crystal morphology, crystallinity, functional groups, elemental composition, compressive strength, porosity and solubility, were then determined. The biological properties, such as protein adsorption and cell attachment, were also evaluated. It was found that the spheroid-like crystals of PHAp were changed into rod-like after fluoride substitution, resulting in a fluoride concentration-dependent increase in compressive strength, as well as a decreased porosity and solubility of the apatite. However, even though the addition of fluoride was demonstrated to enhance protein adsorption and cell attachment of the materials, the most favorable results were intriguingly achieved in FPHAp with the least fluoride content. Collectively, low level of fluoride incorporation is proposed promising for the modification of clinically used BAp based bone substitute materials, because of its being able to maintain a good balance between physicochemical and biological properties of the apatite.

High spatial resolution U-Pb geochronology and Pb isotope geochemistry of magnetite-apatite ore from the Pea Ridge iron oxide-apatite deposit, St. Francois Mountains, southeast Missouri, USA

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Neymark, Leonid; Holm-Denoma, Christopher S.; Pietruszka, Aaron; Aleinikoff, John N.; Fanning, C. Mark; Pillers, Renee M.; Moscati, Richard J.

2016-01-01

The Pea Ridge iron oxide-apatite (IOA) deposit is one of the major rhyolite-hosted magnetite deposits of the St. Francois Mountains terrane, which is located within the Mesoproterozoic (1.5–1.3 Ga) Granite-Rhyolite province in the U.S. Midcontinent. Precise and accurate determination of the timing and duration of oreforming processes in this deposit is crucial for understanding its origin and placing it within a deposit-scale and regional geologic context. Apatite and monazite, well-established U-Pb mineral geochronometers, are abundant in the Pea Ridge orebody. However, the potential presence of multiple generations of dateable minerals, processes of dissolution-reprecipitation, and occurrence of micrometer-sized intergrowths and inclusions complicate measurements and interpretations of the geochronological results. Here, we employ a combination of several techniques, including ID-TIMS and high spatial resolution geochronology of apatite and monazite using LA-SC-ICPMS and SHRIMP, and Pb isotope geochemistry of pyrite and magnetite to obtain the first direct age constraints on the formation and alteration history of the Pea Ridge IOA deposit. The oldest apatite TIMS 207Pb*/206Pb* dates are 1471 ± 1 and 1468 ± 1 Ma, slightly younger than (but within error of) the ~1474 to ~1473 Ma U-Pb zircon ages of the host rhyolites. Dating of apatite and monazite inclusions within apatite provides evidence for at least one younger metasomatic event at ~1.44 Ga, and possibly multiple superimposed metasomatic events between 1.47 and 1.44 Ga. Lead isotop analyses of pyrite show extremely radiogenic 206Pb/204Pb ratios up to ~80 unsupported by in situ U decay. This excess radiogenic Pb in pyrite may have been derived from the spatially associated apatite as apatite recrystallized several tens of million years after its formation. The low initial 206Pb/204Pb ratio of ~16.5 and 207Pb/204Pb ratio of ~15.4 for individual magnetite grains indicate closed U-Pb system behavior in

Study on removal effect and mechanism of uranium by hydroxyapatite and natural apatite

International Nuclear Information System (INIS)

Zhang Xiaofeng; Chen Diyun; Tu Guoqing; Huang Xiaozhui

2014-01-01

By the static experiments, the effects of reaction time, pH value, initial concentration of uranium, dosage of apatite on adsorption of hydroxyapatite and natural apatite for uranium were studied respectively. The adsorption process was analyzed by thermodynamics and kinetics, and the adsorption mechanism was analyzed by infrared spectroscopy, X-ray diffraction and scanning electron microscope. The results of hydroxyapatite show that the removal capacity of uranium increases with the initial concentration of uranium, and the adsorption rate of hydroxyapatite on UO_2"2"+ reaches 85%, when the pH value is 4 to 5 and dosage of hydroxyapatite is 0.75 g. The results of natural apatite show that the removal capacity of uranium increases with the initial concentration of uranium, and the adsorption rate of natural apatite on UO_2"2"+ is up to 80%, when the pH value is 3 and dosage of hydroxyapatite is l.0 g. Similarly, at 120 minutes both of the removal reactions by hydroxyapatite and natural apatite substantially reach equilibrium. Moreover, both of the reactions by hydroxyapatite and natural apatite are in line with quasi secondary dynamics equation, and follow the Langmuir adsorption isotherm. Infrared spectra indicate that the removal of hydroxyapatite for uranium depends on the complexation of phosphate, which is almost the same as that of natural apatite. X-ray diffraction analysis shows that hydroxyapatite has the composition and structure of pure material, whereas the natural apatite is mainly composed of Ca_5H_2(PO_4)_3F and Ca_8H_2(PO_4)_6H_2O. In addition, scanning electron microscope demonstrates that hydroxyapatite has the appearance of spherical with a hole and the hole has a cavity containing a large amount of floc, while the surface becomes smooth and pores are closed after removal of uranium, which is due to the adsorption of UO_2"2"+ leading a link between molecules on hydroxyapatite surface. But for natural apatite, it depicts the angular mineral shape

Hydrogel/bioactive glass composites for bone regeneration applications: Synthesis and characterisation

International Nuclear Information System (INIS)

Killion, John A.; Kehoe, Sharon; Geever, Luke M.; Devine, Declan M.; Sheehan, Eoin; Boyd, Daniel; Higginbotham, Clement L.

2013-01-01

Due to the deficiencies of current commercially available biological bone grafts, alternative bone graft substitutes have come to the forefront of tissue engineering in recent times. The main challenge for scientists in manufacturing bone graft substitutes is to obtain a scaffold that has sufficient mechanical strength and bioactive properties to promote formation of new tissue. The ability to synthesise hydrogel based composite scaffolds using photopolymerisation has been demonstrated in this study. The prepared hydrogel based composites were characterised using techniques including Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy-dispersive X-ray spectrometry (EDX), rheological studies and compression testing. In addition, gel fraction, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), porosity and swelling studies of the composites were carried out. It was found that these novel hydrogel bioglass composite formulations did not display the inherent brittleness that is typically associated with bioactive glass based bone graft materials and exhibited enhanced biomechanical properties compared to the polyethylene glycol hydrogel scaffolds along. Together, the combination of enhanced mechanical properties and the deposition of apatite on the surface of these hydrogel based composites make them an ideal candidate as bone graft substitutes in cancellous bone defects or low load bearing applications. Highlights: • Young's modulus increases with the addition of bioactive glasses. • Hydrogel based composites formed an apatite layer in simulated body fluid. • Storage modulus increases with addition of bioactive glasses. • Compressive strength is dependent on molecular weight and bioactive glass loading

Sub-µm structure and volatile distribution of shocked lunar apatite

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Cernok, A.; White, L. F.; Darling, J.; Dunlop, J.; Fougerouse, D.; William, R. D. A.; Reddy, S.; Saxey, D. W.; Zhao, X.; Franchi, I.; Anand, M.

2017-12-01

Apatite is a key mineral broadly used for studying volatiles in planetary materials. Most studies in this recent frontier of planetary exploration focus on volatile content and respective isotopic composition in apatite. However, there is an imperative to contextualize geochemical data with impact-induced features, given that most planetary materials experienced at least some shock deformation. This study aims at understanding the effect of high-level shock deformation on volatile distribution in apatite from lunar highlands samples. Combining Electron Backscatter Diffraction (EBSD), NanoSIMS and Atom Probe Microscopy (APM) analyses we are gaining an insight into the µm- and nm-scale structural variation in apatite from a shocked, maskelynite- and impact-melt-bearing norite. EBSD revealed degraded crystallinity, high density of low angle grain boundaries and domains of sub-µm granular features that appear amorphous at this length scales ( 80 x 40 nm). Texture component maps show up to 25° misorientation within a single grain - evidence of severe crystal-plastic deformation, but with no obvious evidence of recrystallization. APM revealed complex microstructure of the apparently amorphous domains defined by well developed, straight to slightly curved grain boundaries meeting at 120° triple junctions. This equilibrium texture is probably accommodated by annealing and recrystallization of apatite due to the post-shock heating. Crystallites range in size from 50 to 100 nm. Grain boundaries are defined by segregation of Mg, Si and Fe impurities, which possibly originate from surrounding phases. Cl and F show homogenous distribution over the length scale of the APM analysis (1 to 500 nm). H2O content measurements of 250-600 ppm by NanoSIMS are consistent with the lower range of previously reported values for this rock, with no obvious correlation with the level of crystallinity. δD values are confirmed to be terrestrial-like and relatively constant. These preliminary

Rare Earth Element Behaviour in Apatite from the Olympic Dam Cu–U–Au–Ag Deposit, South Australia

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Sasha Krneta

2017-08-01

Full Text Available Apatite is a common magmatic accessory in the intrusive rocks hosting the giant ~1590 Ma Olympic Dam (OD iron-oxide copper gold (IOCG ore system, South Australia. Moreover, hydrothermal apatite is a locally abundant mineral throughout the altered and mineralized rocks within and enclosing the deposit. Based on compositional data for zoned apatite, we evaluate whether changes in the morphology and the rare earth element and Y (REY chemistry of apatite can be used to constrain the fluid evolution from early to late hydrothermal stages at OD. The ~1.6 Ga Roxby Downs granite (RDG, host to the OD deposit, contains apatite as a magmatic accessory, locally in the high concentrations associated with mafic enclaves. Magmatic apatite commonly contains REY-poor cores and REY-enriched margins. The cores display a light rare earth element (LREE-enriched chondrite-normalized fractionation pattern with a strong negative Eu anomaly. In contrast, later hydrothermal apatite, confined to samples where magmatic apatite has been obliterated due to advanced hematite-sericite alteration, displays a conspicuous, convex, middle rare earth element (MREE-enriched pattern with a weak negative Eu anomaly. Such grains contain abundant inclusions of florencite and sericite. Within high-grade bornite ores from the deposit, apatite displays an extremely highly MREE-enriched chondrite-normalized fractionation trend with a positive Eu anomaly. Concentrations of U and Th in apatite mimic the behaviour of ∑REY and are richest in magmatic apatite hosted by RDG and the hydrothermal rims surrounding them. The shift from characteristic LREE-enriched magmatic and early hydrothermal apatite to later hydrothermal apatite displaying marked MREE-enriched trends (with lower U, Th, Pb and ∑REY concentrations reflects the magmatic to hydrothermal transition. Additionally, the strong positive Eu anomaly in the MREE-enriched trends of apatite in high-grade bornite ores are attributable to

An investigation of the mineral in ductile and brittle cortical mouse bone.

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Rodriguez-Florez, Naiara; Garcia-Tunon, Esther; Mukadam, Quresh; Saiz, Eduardo; Oldknow, Karla J; Farquharson, Colin; Millán, José Luis; Boyde, Alan; Shefelbine, Sandra J

2015-05-01

Bone is a strong and tough material composed of apatite mineral, organic matter, and water. Changes in composition and organization of these building blocks affect bone's mechanical integrity. Skeletal disorders often affect bone's mineral phase, either by variations in the collagen or directly altering mineralization. The aim of the current study was to explore the differences in the mineral of brittle and ductile cortical bone at the mineral (nm) and tissue (µm) levels using two mouse phenotypes. Osteogenesis imperfecta model, oim(-/-) , mice have a defect in the collagen, which leads to brittle bone; PHOSPHO1 mutants, Phospho1(-/-) , have ductile bone resulting from altered mineralization. Oim(-/-) and Phospho1(-/-) were compared with their respective wild-type controls. Femora were defatted and ground to powder to measure average mineral crystal size using X-ray diffraction (XRD) and to monitor the bulk mineral to matrix ratio via thermogravimetric analysis (TGA). XRD scans were run after TGA for phase identification to assess the fractions of hydroxyapatite and β-tricalcium phosphate. Tibiae were embedded to measure elastic properties with nanoindentation and the extent of mineralization with backscattered electron microscopy (BSE SEM). Results revealed that although both pathology models had extremely different whole-bone mechanics, they both had smaller apatite crystals, lower bulk mineral to matrix ratio, and showed more thermal conversion to β-tricalcium phosphate than their wild types, indicating deviations from stoichiometric hydroxyapatite in the original mineral. In contrast, the degree of mineralization of bone matrix was different for each strain: brittle oim(-/-) were hypermineralized, whereas ductile Phospho1(-/-) were hypomineralized. Despite differences in the mineralization, nanoscale alterations in the mineral were associated with reduced tissue elastic moduli in both pathologies. Results indicated that alterations from normal crystal size

Transformation of apatite phosphorus and non-apatite inorganic phosphorus during incineration of sewage sludge.

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Li, Rundong; Zhang, Ziheng; Li, Yanlong; Teng, Wenchao; Wang, Weiyun; Yang, Tianhua

2015-12-01

The recovery of phosphorus from incinerated sewage sludge ash (SSA) is assumed to be economical. Transformation from non-apatite inorganic phosphorus (NAIP) to apatite phosphorus (AP), which has a higher bioavailability and more extensive industrial applications, was studied at 750-950°C by sewage sludge incineration and model compound incineration with a calcium oxide (CaO) additive. Thermogravimetric differential scanning calorimetry analysis and X-ray diffraction measurements were used to analyze the reactions between NAIP with CaO and crystallized phases in SSA. High temperatures stimulated the volatilization of NAIP instead of AP. Sewage sludge incineration with CaO transformed NAIP into AP, and the percentage of AP from the total phosphorus reached 99% at 950°C. Aluminum phosphate reacted with CaO, forming Ca2P2O7 and Ca3(PO4)2 at 750-950°C. Reactions between iron phosphate and CaO occurred at lower temperatures, forming Ca(PO3)2 before reaching 850°C. Copyright © 2015 Elsevier Ltd. All rights reserved.

Prestroke CHA2DS2-VASc Score and Severity of Acute Stroke in Patients with Atrial Fibrillation: Findings from RAF Study.

Science.gov (United States)

Acciarresi, Monica; Paciaroni, Maurizio; Agnelli, Giancarlo; Falocci, Nicola; Caso, Valeria; Becattini, Cecilia; Marcheselli, Simona; Rueckert, Christina; Pezzini, Alessandro; Morotti, Andrea; Costa, Paolo; Padovani, Alessandro; Csiba, Laszló; Szabó, Lilla; Sohn, Sung-Il; Tassinari, Tiziana; Abdul-Rahim, Azmil H; Michel, Patrik; Cordier, Maria; Vanacker, Peter; Remillard, Suzette; Alberti, Andrea; Venti, Michele; D'Amore, Cataldo; Scoditti, Umberto; Denti, Licia; Orlandi, Giovanni; Chiti, Alberto; Gialdini, Gino; Bovi, Paolo; Carletti, Monica; Rigatelli, Alberto; Putaala, Jukka; Tatlisumak, Turgut; Masotti, Luca; Lorenzini, Gianni; Tassi, Rossana; Guideri, Francesca; Martini, Giuseppe; Tsivgoulis, Georgios; Vadikolias, Kostantinos; Liantinioti, Chrissoula; Corea, Francesco; Del Sette, Massimo; Ageno, Walter; De Lodovici, Maria Luisa; Bono, Giorgio; Baldi, Antonio; D'Anna, Sebastiano; Sacco, Simona; Carolei, Antonio; Tiseo, Cindy; Imberti, Davide; Zabzuni, Dorjan; Doronin, Boris; Volodina, Vera; Consoli, Domenico; Galati, Franco; Pieroni, Alessio; Toni, Danilo; Monaco, Serena; Baronello, Mario Maimone; Barlinn, Kristian; Pallesen, Lars-Peder; Kepplinger, Jessica; Bodechtel, Ulf; Gerber, Johannes; Deleu, Dirk; Melikyan, Gayane; Ibrahim, Faisal; Akhtar, Naveed; Mosconi, Maria Giulia; Lees, Kennedy R

2017-06-01

The aim of this study was to investigate for a possible association between both prestroke CHA 2 DS 2 -VASc score and the severity of stroke at presentation, as well as disability and mortality at 90 days, in patients with acute stroke and atrial fibrillation (AF). This prospective study enrolled consecutive patients with acute ischemic stroke, AF, and assessment of prestroke CHA 2 DS 2 -VASc score. Severity of stroke was assessed on admission using the National Institutes of Health Stroke Scale (NIHSS) score (severe stroke: NIHSS ≥10). Disability and mortality at 90 days were assessed by the modified Rankin Scale (mRS <3 or ≥3). Multiple logistic regression was used to correlate prestroke CHA 2 DS 2 -VASc and severity of stroke, as well as disability and mortality at 90 days. Of the 1020 patients included in the analysis, 606 patients had an admission NIHSS score lower and 414 patients higher than 10. At 90 days, 510 patients had mRS ≥3. A linear correlation was found between the prestroke CHA 2 DS 2 -VASc score and severity of stroke (P = .001). On multivariate analysis, CHA 2 DS 2 -VASc score correlated with severity of stroke (P = .041) and adverse functional outcome (mRS ≥3) (P = .001). A logistic regression with the receiver operating characteristic graph procedure (C-statistics) evidenced an area under the curve of .60 (P = .0001) for severe stroke. Furthermore, a correlation was found between prestroke CHA 2 DS 2 -VASc score and lesion size. In patients with AF, in addition to the risk of stroke, a high CHA 2 DS 2 -VASc score was independently associated with both stroke severity at onset and disability and mortality at 90 days. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Chaînes d'exploits scénarios de hacking avancés et prévention

CERN Document Server

Whitaker, Andrew; Voth, Jack B

2009-01-01

Un pirate informatique s'appuie rarement sur une unique attaque, mais utilise plutôt des chaînes d'exploits, qui impliquent plusieurs méthodes et attaques coordonnées, pour atteindre sa cible et arriver à ses fins. Ces chaînes d'exploits sont généralement complexes et difficiles à prévenir. Or la plupart des ouvrages de sécurité ne les couvrent pas, ou sinon de manière superficielle. Cet ouvrage présente en profondeur les principales chaînes d'exploits qui sévissent actuellement. À travers des exemples basés sur des stratégies d'attaques réelles, utilisant les outils actuels les plus courants et visant des cibles importantes comme des données bancaires ou de sécurité sociale, vous découvrirez le spectre complet des attaques, des réseaux sans-fil à l'accès physique en passant par l'ingénierie sociale. Dans chaque scénario, les exploits sont décortiqués un à un en vue d'expliquer la chaîne qui va conduire à l'attaque finale. Les mesures de prévention à appliquer pour éviter...

Study of damage and helium diffusion in fluoro-apatites

International Nuclear Information System (INIS)

Miro, S.

2004-12-01

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)

A multiscale theoretical investigation of electric measurements in living bone : piezoelectricity and electrokinetics.

Science.gov (United States)

Lemaire, T; Capiez-Lernout, E; Kaiser, J; Naili, S; Rohan, E; Sansalone, V

2011-11-01

This paper presents a theoretical investigation of the multiphysical phenomena that govern cortical bone behaviour. Taking into account the piezoelectricity of the collagen-apatite matrix and the electrokinetics governing the interstitial fluid movement, we adopt a multiscale approach to derive a coupled poroelastic model of cortical tissue. Following how the phenomena propagate from the microscale to the tissue scale, we are able to determine the nature of macroscopically observed electric phenomena in bone.

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.

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

International Nuclear Information System (INIS)

Chowdhury, E.H.

2011-01-01

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.

Improvement of RVNRL film properties by adding fumed silica and hydroxy apatite

Directory of Open Access Journals (Sweden)

Adul Thiangchanya

2003-01-01

Full Text Available The effect of adding fumed silica and hydroxy apatite to Radiation Vulcanized Natural Rubber Latex (RVNRL for improving tear strength, aging properties, degradability and water-soluble protein content of rubber films has been investigated. The addition of fumed silica and hydroxy apatite in RVNRL improves tear strength and aging properties of rubber films, whereas tensile strength and degradability of rubber films were unchanged during storage at room temperature. The water-soluble protein content in rubber films was reduced by immobilization of the fumed silica and hydroxy apatite and enhanced by addition of ZnO. This may reduce allergy problems of natural rubber latex products caused by water-soluble protein. The MST of the RVNRL with fumed silica and hydroxy apatite indicated that the latex must be used within two months after mixing because of its stability.

Identifying compositional and structural changes in spongy and subchondral bone from the hip joints of patients with osteoarthritis using Raman spectroscopy

Science.gov (United States)

Buchwald, Tomasz; Niciejewski, Krzysztof; Kozielski, Marek; Szybowicz, Mirosław; Siatkowski, Marcin; Krauss, Hanna

2012-01-01

Raman microspectroscopy was used to examine the biochemical composition and molecular structure of extracellular matrix in spongy and subchondral bone collected from patients with clinical and radiological evidence of idiopathic osteoarthritis of the hip and from patients who underwent a femoral neck fracture, as a result of trauma, without previous clinical and radiological evidence of osteoarthritis. The objectives of the study were to determine the levels of mineralization, carbonate accumulation and collagen quality in bone tissue. The subchondral bone from osteoarthritis patients in comparison with control subject is less mineralized due to a decrease in the hydroxyapatite concentration. However, the extent of carbonate accumulation in the apatite crystal lattice increases, most likely due to deficient mineralization. The alpha helix to random coil band area ratio reveals that collagen matrix in subchondral bone is more ordered in osteoarthritis disease. The hydroxyapatite to collagen, carbonate apatite to hydroxyapatite and alpha helix to random coil band area ratios are not significantly changed in the differently loaded sites of femoral head. The significant differences also are not visible in mineral and organic constituents' content in spongy bone beneath the subchondral bone in osteoarthritis disease.

Apatite in carbonatitic rocks: Compositional variation, zoning, element partitioning and petrogenetic significance

Science.gov (United States)

Chakhmouradian, Anton R.; Reguir, Ekaterina P.; Zaitsev, Anatoly N.; Couëslan, Christopher; Xu, Cheng; Kynický, Jindřich; Mumin, A. Hamid; Yang, Panseok

2017-03-01

Apatite-group phosphates are nearly ubiquitous in carbonatites, but our understanding of these minerals is inadequate, particularly in the areas of element partitioning and petrogenetic interpretation of their compositional variation among spatially associated rocks and within individual crystals. In the present work, the mode of occurrence, and major- and trace-element chemistry of apatite (sensu lato) from calcite and dolomite carbonatites, their associated cumulate rocks (including phoscorites) and hydrothermal parageneses were studied using a set of 80 samples from 50 localities worldwide. The majority of this set represents material for which no analytical data are available in the literature. Electron-microprobe and laser-ablation mass-spectrometry data ( 600 and 400 analyses, respectively), accompanied by back-scattered-electron and cathodoluminescence images and Raman spectra, were used to identify the key compositional characteristics and zoning patterns of carbonatitic apatite. These data are placed in the context of phosphorus geochemistry in carbonatitic systems and carbonatite evolution, and compared to the models proposed by previous workers. The documented variations in apatite morphology and zoning represent a detailed record of a wide range of evolutionary processes, both magmatic and fluid-driven. The majority of igneous apatite from the examined rocks is Cl-poor fluorapatite or F-rich hydroxylapatite (≥ 0.3 apfu F) with 0.2-2.7 wt.% SrO, 0-4.5 wt.% LREE2O3, 0-0.8 wt.% Na2O, and low levels of other cations accommodated in the Ca site (up to 1000 ppm Mn, 2300 ppm Fe, 200 ppm Ba, 150 ppm Pb, 700 ppm Th and 150 ppm U), none of which show meaningful correlation with the host-rock type. Silicate, (SO4)2 - and (VO4)3 - anions, substituting for (PO4)3 -, tend to occur in greater abundance in crystals from calcite carbonatites (up to 4.2 wt.% SiO2, 1.5 wt.% SO3 and 660 ppm V). Although (CO3)2 - groups are very likely present in some samples, Raman micro

Thermodynamic Mixing Behavior Of F-OH Apatite Crystalline Solutions

Science.gov (United States)

Hovis, G. L.

2011-12-01

It is important to establish a thermodynamic data base for accessory minerals and mineral series that are useful in determining fluid composition during petrologic processes. As a starting point for apatite-system thermodynamics, Hovis and Harlov (2010, American Mineralogist 95, 946-952) reported enthalpies of mixing for a F-Cl apatite series. Harlov synthesized all such crystalline solutions at the GFZ-Potsdam using a slow-cooled molten-flux method. In order to expand thermodynamic characterization of the F-Cl-OH apatite system, a new study has been initiated along the F-OH apatite binary. Synthesis of this new series made use of National Institute of Standards and Technology (NIST) 2910a hydroxylapatite, a standard reference material made at NIST "by solution reaction of calcium hydroxide with phosphoric acid." Synthesis efforts at Lafayette College have been successful in producing fluorapatite through ion exchange between hydroxylapatite 2910a and fluorite. In these experiments, a thin layer of hydroxylapatite powder was placed on a polished CaF2 disc (obtained from a supplier of high-purity crystals for spectroscopy), pressed firmly against the disc, then annealed at 750 °C (1 bar) for three days. Longer annealing times did not produce further change in unit-cell dimensions of the resulting fluorapatite, but it is uncertain at this time whether this procedure produces a pure-F end member (chemical analyses to be performed in the near future). It is clear from the unit-cell dimensions, however, that the newly synthesized apatite contains a high percentage of fluorine, probably greater than 90 mol % F. Intermediate compositions for a F-OH apatite series were made by combining 2910a hydroxylapatite powder with the newly synthesized fluorapatite in various proportions, then conducting chemical homogenization experiments at 750 °C on each mixture. X-ray powder diffraction data indicated that these experiments were successful in producing chemically homogeneous

A structural approach in the study of bones: fossil and burnt bones at nanosize scale

Science.gov (United States)

Piga, Giampaolo; Baró, Maria Dolors; Escobal, Irati Golvano; Gonçalves, David; Makhoul, Calil; Amarante, Ana; Malgosa, Assumpció; Enzo, Stefano; Garroni, Sebastiano

2016-12-01

We review the different factors affecting significantly mineral structure and composition of bones. Particularly, it is assessed that micro-nanostructural and chemical properties of skeleton bones change drastically during burning; the micro- and nanostructural changes attending those phases manifest themselves, amongst others, in observable alterations to the bones colour, morphology, microstructure, mechanical strength and crystallinity. Intense changes involving the structure and chemical composition of bones also occur during the fossilization process. Bioapatite material is contaminated by an heavy fluorination process which, on a long-time scale reduces sensibly the volume of the original unit cell, mainly the a-axis of the hexagonal P63/m space group. Moreover, the bioapatite suffers to a varying degree of extent by phase contamination from the nearby environment, to the point that rarely a fluorapatite single phase may be found in fossil bones here examined. TEM images supply precise and localized information, on apatite crystal shape and dimension, and on different processes that occur during thermal processes or fossilization of ancient bone, complementary to that given by X-ray diffraction and Attenuated Total Reflection Infrared spectroscopy. We are presenting a synthesis of XRD, ATR-IR and TEM results on the nanostructure of various modern, burned and palaeontological bones.

Magnetite-apatite-dolomitic rocks of Ust-Chulman (Aldan shield, Russia): Seligdar-type carbonatites?

Science.gov (United States)

Prokopyev, Ilya R.; Doroshkevich, Anna G.; Redina, Anna A.; Obukhov, Andrey V.

2018-04-01

The Ust-Chulman apatite ore body is situated within the Nimnyrskaya apatite zone at the Aldan shield in Russia. The latest data confirm the carbonatitic origin of the Seligdar apatite deposit (Prokopyev et al. in Ore Geol Rev 81:296-308, 2017). The results of our investigations demonstrate that the magnetite-apatite-dolomitic rocks of the Ust-Chulman are highly similar to Seligdar-type dolomitic carbonatites in terms of the mineralogy and the fluid regime of formation. The ilmenite and spinel mineral phases occur as solid solutions with magnetite, and support the magmatic origin of the Ust-Chulman ores. The chemical composition of REE- and SO3-bearing apatite crystals and, specifically, monazite-(Ce) mineralisation and the formation of Nb-rutile, late hydrothermal sulphate minerals (barite, anhydrite) and haematite are typical for carbonatite complexes. The fluid inclusions study revealed similarities to the evolutionary trend of the Seligdar carbonatites that included changes of the hydrothermal solutions from highly concentrated chloride to medium-low concentrated chloride-sulphate and oxidized carbonate-ferrous.

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.

Acceleration of biomimetic mineralization to apply in bone regeneration

International Nuclear Information System (INIS)

Jayasuriya, A Champa; Shah, Chiragkumar; Ebraheim, Nabil A; Jayatissa, Ahalapitiya H

2008-01-01

The delivery of growth factors and therapeutic drugs into bone defects is a major clinical challenge. Biomimetically prepared bone-like mineral (BLM) containing a carbonated apatite layer can be used to deliver growth factors and drugs in a controlled manner. In the conventional biomimetic process, BLM can be deposited on the biodegradable polymer surfaces by soaking them in simulated body fluid (SBF) for 16 days or more. The aim of this study was to accelerate the biomimetic process of depositing BML in the polymer surfaces. We accelerated the deposition of mineral on 3D poly(lactic-co-glycolic acid) (PLGA) porous scaffolds to 36-48 h by modifying the biomimetic process parameters and applying surface treatments to PLGA scaffolds. The BLM was coated on scaffolds after surface treatments followed by incubation at 37 0 C in 15 ml of 5x SBF. We characterized the BLM created using the accelerated biomineralization process with wide angle x-ray diffraction (XRD), Fourier transform infrared (FTIR) microscopy, and scanning electron microscopy (SEM). The FTIR and XRD analyses of mineralized scaffolds show similarities between biomimetically prepared BLM, and bone bioapatite and carbonated apatite. We also found that the BLM layer on the surface of scaffolds was stable even after 21 days immersed in Tris buffered saline and cell culture media. This study suggests that BLM was stable for at least 3 weeks in both media, and therefore, BLM has a potential for use as a carrier for biological molecules for localized release applications as well as bone tissue engineering applications

IN SITU LEAD IMMOBILIZATION BY APATITE

Science.gov (United States)

Lead contamination is of environmental concern due to its effect on human health. The purpose of this study was to develop a technology to immobilize Pb in situ in contaminated soils and wastes using apatite. Hydroxyapatite [Ca10(PO4)6(O...

Apatite: A New Tool For Understanding The Temporal Variability Of Magmatic Volatile Contents

Science.gov (United States)

Stock, M. J.; Humphreys, M.; Smith, V.; Pyle, D. M.; Isaia, R.

2015-12-01

The apatite crystal structure is capable of incorporating H2O, F and Cl, as well as trace CO2 and sulphur. These can be related to parental magma compositions through application of a series of pressure and temperature-dependent exchange reactions (Piccoli and Candela, 1994), permitting apatite crystals to preserve a record of all major volatile species in the melt. Furthermore, due to the general incompatibility of P in other rock-forming minerals, apatite is ubiquitous in igneous systems and often begins crystallising early, such that apatite inclusions within phenocrysts record melt volatile contents throughout magmatic differentiation. In this work, we compare the compositions of apatite inclusions and microphenocrysts with pyroxene-hosted melt inclusions from the Astroni 1 eruption of Campi Flegrei, Italy. These data are coupled with magmatic differentiation models (Gualda et al., 2012), experimental volatile solubility data (Webster et al., 2014) and thermodynamic models of apatite compositional variations (Piccoli and Candela, 1994) to determine a time-series of magmatic volatile evolution in the build-up to eruption. We find that apatite halogen/OH ratios decreased through magmatic differentiation, while melt inclusion F and Cl concentrations increased. Melt inclusion H2O contents are constant at ~2.5 wt%. These data are best explained by volatile-undersaturated differentiation over most of the crystallisation history of the Astroni 1 melt, with melt inclusion H2O contents reset during ascent, due to rapid H diffusion through the phenocryst hosts (Woods et al., 2000). Given the rapid diffusivity of volatiles in apatite (Brenan, 1993), preservation of undersaturated compositions in microphenocrysts suggests that saturation was only achieved a few days to months before eruption and that it may have been the transition into a volatile-saturated state that ultimately triggered eruption. Piccoli and Candela, 1994. Am. J. of Sc., 294, 92-135. Gualda et al., 2012

Sr, Mg cosubstituted HA porous macro-granules: potentialities as resorbable bone filler with antiosteoporotic functions.

Science.gov (United States)

Landi, Elena; Uggeri, Jacopo; Medri, Valentina; Guizzardi, Stefano

2013-09-01

Porous macro-granules of nanostructured apatite with Ca ions partially cosubstituted with Mg and Sr ions in different ratios (SrMgHAs), were synthesized at 37°C and compared with Mg and/or Sr free apatites (MgHAs and HA). Strontium improved the Mg substitution extent in the apatite and the chemical-physical and thermal stability of the resulting cosubstituted apatite. Porous macro-granules of 400-600 micron with selected composition were tested for the ionic release in synthetic body fluid and the data were related with the results of preliminary cell investigation in vitro. As compared to the corresponding Sr-free granulate, the SrMgHA could be exploited to prolong the beneficial Mg release during the bone regeneration process. In addition the contemporary in situ supply of Sr, an antiosteoporotic and anticarie ion, could influence the quality of new hard tissues. The ionic multirelease created a more favorable environment for human osteoblasts, demonstrated by a proliferative effect for each dose tested in the range 0.1-10 mg/mL. Copyright © 2013 Wiley Periodicals, Inc.

Liquid Phase Sintered Ceramic Bone Scaffolds by Combined Laser and Furnace

Directory of Open Access Journals (Sweden)

Pei Feng

2014-08-01

Full Text Available Fabrication of mechanically competent bioactive scaffolds is a great challenge in bone tissue engineering. In this paper, β-tricalcium phosphate (β-TCP scaffolds were successfully fabricated by selective laser sintering combined with furnace sintering. Bioglass 45S5 was introduced in the process as liquid phase in order to improve the mechanical and biological properties. The results showed that sintering of β-TCP with the bioglass revealed some features of liquid phase sintering. The optimum amount of 45S5 was 5 wt %. At this point, the scaffolds were densified without defects. The fracture toughness, compressive strength and stiffness were 1.67 MPam1/2, 21.32 MPa and 264.32 MPa, respectively. Bone like apatite layer was formed and the stimulation for apatite formation was increased with increase in 45S5 content after soaking in simulated body fluid, which indicated that 45S5 could improve the bioactivity. Furthermore, MG-63 cells adhered and spread well, and proliferated with increase in the culture time.

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.

The impact of bacteria of circulating water on apatite-nepheline ore flotation.

Science.gov (United States)

Evdokimova, G A; Gershenkop, A Sh; Fokina, N V

2012-01-01

A new phenomenon has been identified and studied-the impact of bacteria on the benefication process of non-sulphide ores using circulating water supply-a case study of apatite-nepheline ore. It is shown that bacteria deteriorate the floatability of apatite due to their interaction with active centres of calcium-containing minerals and intense flocculation, resulting in a decrease of the flotation process selectivity thus deteriorating the quality of concentrate. Based on the comparative analysis of primary sequences of 16S rRNA genes, there have been identified dominating bacteria species, recovered from the circulating water used at apatite-nepheline concentrating mills, and their phylogenetic position has been determined. All the bacteria were related to γ-Proteobacteria, including the Acinetobacter species, Pseudomonas alcaliphila, Ps. plecoglossicida, Stenotrophomonas rhizophila. A method of non-sulphide ores flotation has been developed with consideration of the bacterial factor. It consists in use of small concentrations of sodium hypochlorite, which inhibits the development of bacteria in the flotation of apatite-nepheline ores.

Theoretical stability assessment of uranyl phosphates and apatites: Selection of amendments for in situ remediation of uranium

International Nuclear Information System (INIS)

Raicevic, S.; Wright, J.V.; Veljkovic, V.; Conca, J.L.

2006-01-01

Addition of an amendment or reagent to soil/sediment is a technique that can decrease mobility and reduce bioavailability of uranium (U) and other heavy metals in the contaminated site. According to data from literature and results obtained in field studies, the general mineral class of apatites was selected as a most promising amendment for in situ immobilization/remediation of U. In this work we presented theoretical assessment of stability of U(VI) in four apatite systems (hydroxyapatite (HAP), North Carolina Apatite (NCA), Lisina Apatite (LA), and Apatite II) in order to determine an optimal apatite soil amendment which could be used for in situ remediation of uranium. In this analysis we used a theoretical criterion which is based on calculation of the ion-ion interaction potential, representing the main term of the cohesive energy of the matrix/pollutant system. The presented results of this analysis indicate (i) that the mechanism of immobilization of U by natural apatites depends on their chemical composition and (ii) that all analyzed apatites represent, from the point of view of stability, promising materials which could be used in field remediation of U-contaminated sites

Compositional Variation of Terrestrial Mantle Apatites and Implications for the Halogen and Water Budgets of the Terrestrial Mantle

Science.gov (United States)

Roden, M.; Patino Douce, A. E.; Chaumba, J. B.; Fleisher, C.; Yogodzinski, G. M.

2011-12-01

Apatite in ultramafic xenoliths from various tectonic enviroments including arc (Kamchatka), plume (Hawaii), and intraplate (Lunar Crater, Nunivak, Colorado Plateau) were analyzed by electron microprobe with the aim of characterizing the Cl and F contents, and from these measured compositions to infer the nature of fluids/melts that the apatites equilibrated with. The impetus for the study derived from the generalization of O'Reilly and Griffin (1) that mantle-derived metasomatic apatites tend to be Cl-rich and mantle-derived igneous apatites tend to be F-rich. Our work largely corroborates their generalization with Cl- and/or H2O-rich compositions characterizing the apatites from Nunivak and Kamchatka while apatites from igneous or Group II xenoliths tend to be Cl-poor and be either nearly pure fluorapatite or a mix of hydroxylapatite and fluorapatite. We attribute the Cl-rich nature of the Kamchatka apatites to formation from Cl-rich fluids generated from subducted lithosphere; however the Nunivak occurrence is far removed from subducted lithosphere and may reflect a deep seated source for Cl as also indicated by brine inclusions in diamonds, Cl-rich apatites in carbonate-bearing xenoliths and a Cl-rich signature in some plumes such as Iceland, Azores and Samoa. One curious aspect of mantle-derived apatite compositions is that xenoliths with evidence of carbonatitic metasomatism commonly have Cl-rich apatites while apatites from carbonatites are invariably Cl-poor - perhaps reflecting loss of Cl in fluids evolved from the carbonatitic magma. Apatites from Group II xenoliths at Hawaii are solid solutions between fluorapatite and hydroxylapatite and show no evidence for deep-seated Cl at Hawaii. Samples of the terrestrial mantle are almost uniformly characterized by mineral assemblages with a single Ca-rich phosphate phase but the mantles of Mars, Vesta and the Moon have two Ca-rich phosphates, apatite and volatile-poor merrillite - apatite compositions existing

Predictive value of CHADS2 and CHA2DS2-VASc scores for acute myocardial infarction in patients with atrial fibrillation.

Science.gov (United States)

Pang, Hui; Han, Bing; Fu, Qiang; Zong, Zhenkun

2017-07-05

The presence of acute myocardial infarction (AMI) confers a poor prognosis in atrial fibrillation (AF), associated with increased mortality dramatically. This study aimed to evaluate the predictive value of CHADS 2 and CHA 2 DS 2 -VASc scores for AMI in patients with AF. This retrospective study enrolled 5140 consecutive nonvalvular AF patients, 300 patients with AMI and 4840 patients without AMI. We identified the optimal cut-off values of the CHADS 2 and CHA 2 DS 2 -VASc scores each based on receiver operating characteristic curves to predict the risk of AMI. Both CHADS 2 score and CHA 2 DS 2 -VASc score were associated with an increased odds ratio of the prevalence of AMI in patients with AF, after adjustment for hyperlipidaemia, hyperuricemia, hyperthyroidism, hypothyroidism and obstructive sleep apnea. The present results showed that the area under the curve (AUC) for CHADS 2 score was 0.787 with a similar accuracy of the CHA 2 DS 2 -VASc score (AUC 0.750) in predicting "high-risk" AF patients who developed AMI. However, the predictive accuracy of the two clinical-based risk scores was fair. The CHA 2 DS 2 -VASc score has fair predictive value for identifying high-risk patients with AF and is not significantly superior to CHADS 2 in predicting patients who develop AMI.

The function of Sn(II)-apatite as a Tc immobilizing agent

Energy Technology Data Exchange (ETDEWEB)

Asmussen, R. Matthew, E-mail: matthew.asmussen@pnnl.gov [Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99352 (United States); Neeway, James J.; Lawter, Amanda R.; Levitskaia, Tatiana G. [Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99352 (United States); Lukens, Wayne W. [Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720 (United States); Qafoku, Nikolla P. [Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99352 (United States)

2016-11-15

At the U.S. Department of Energy Hanford Site, Tc-99 is a component of low-activity waste (LAW) fractions of the nuclear tank waste and removal of Tc from LAW streams would greatly benefit the site remediation process. In this study, we investigated the removal of Tc(VII), as pertechnetate, from deionized water (DIW) and a LAW simulant through batch sorption testing and solid phase characterization using tin (II) apatite (Sn-A) and SnCl{sub 2}. Sn-A showed higher levels of Tc removal from both DIW and LAW simulant. Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/XEDS) and X-ray absorption spectroscopy (XAS) of reacted Sn-A in DIW showed that TcO4- is reduced to Tc(IV) on the Sn-A surface. The performance of Sn-A in the LAW simulant was lowered due to a combined effect of the high alkalinity, which lead to an increased dissolution of Sn from the Sn-A, and a preference for the reduction of Cr(VI). - Highlights: • Sn(II)-Apatite shows high proficiency in removing Tc(VII) from neutral solutions. • The removal of the Tc(VII) by Sn(II)-apatite is done via reduction to Tc(IV)O{sub 2} × H{sub 2}O. • In LAW Sn(II)-apatite is less efficient in removing Tc(VII). • Interference in LAW due to a preference for the reduction of Cr(VI) and the high pH. • Sn(II)-apatite can remove Tc(VII) from LAW effectively through increasing material added.

Compression and rupture cycles as tools for compressibility characterization application to apatitic calcium phosphates

Energy Technology Data Exchange (ETDEWEB)

Pontier, C. [S.P.C.T.S., Faculte des Sciences, Limoges (France); G.E.F., Faculte de Pharmacie, Limoges (France); Viana, M.; Chulia, D. [G.E.F., Faculte de Pharmacie, Limoges (France); Champion, E.; Bernache-Assollant, D. [S.P.C.T.S., Faculte des Sciences, Limoges (France)

2002-07-01

Measurement of the cycles of compression and rupture helps to understand the phenomena occurring during compaction. Different parameters are deduced from the cycles, such as the packing of the material and energies used during compression. The ratio between the energy of rupture and the energy of compaction defines the efficacy of compaction of the materials. This technique is applied to ceramic materials using apatitic calcium phosphates with a Ca/P molar ratio of 1.5 (apatitic tricalcium phosphate and {beta}-tricalcium phosphate) and 1.667 (stoichiometric hydroxyapatite). The methodology uses a uniaxial instrumented press to plot the cycles of compaction and rupture. The results point out the good compaction and cohesion properties of apatitic tricalcium phosphate, compared to the other apatitic materials. (orig.)

Apatite formation behaviour during metasomatism in the Bathtub Intrusion (Babbitt deposit, Duluth Complex, USA)

Science.gov (United States)

Raič, Sara; Mogessie, Aberra; Krenn, Kurt; Hauzenberger, Christoph A.; Tropper, Peter

2016-04-01

The mineralized troctolitic Bathtub intrusion (Duluth Complex, NE-Minnesota) is known for its famous Cu-Ni-Sulfide±PGM Babbitt deposit, where platinum group minerals (PGMs) are either hosted by primary magmatic sulfides (base metal sulfides) or associated with hydrothermally altered portions. This secondary generation of PGMs is present in alteration patches and suggests the involvement of hydrothermal fluids in the mobilization of platinum-group elements (PGEs). Accessory fluorapatite in these samples reveals besides H2O- and CO2-rich primary fluid inclusions, textural and compositional variations that also record magmatic and metasomatic events. Based on detailed back-scattered electron imaging (BSE) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICPMS), a primary magmatic origin is reflected by homogeneous or zoned grains, where zoning patterns are either concentric or oscillatory, with respect to LREE. Late magmatic to hydrothermal processes are indicated by grains with bright LREE-enriched rims or conversion textures with REE-enriched patches in the interior of the apatite. A metasomatic formation of monazite from apatite is documented by the presence of monazite inclusions in apatite and newly grown monazite at altered apatite rims. They formed by the release of REEs from the apatite during a fluid-induced alteration, based on the coupled substitution Ca2+ + P5+ = REE3+ + Si4+ (Rønsbo 1989; Rønsbo 2008). Samples with monazite inclusions in apatite further display occurrences of PGMs associated with hydrothermal alteration patches (chlorite + amphibole). The presence of H2O- and CO2-rich fluid inclusions in apatite, the metasomatically induced monazite growth, as well as the occurrence of PGMs in hydrothermally alteration zones, also suggest the involvement of aqueous chloride complexes in a H2O dominated fluid in the transportation of LREE and redistribution of the second generation of PGEs. Rønsbo, J.G. (1989): Coupled substitutions

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.

Inclusions in bone material as a source of error in radiocarbon dating

International Nuclear Information System (INIS)

Hassan, A.A.; Ortner, D.J.

1977-01-01

Electron probe microanalysis, X-ray diffraction and microscopic examination were conducted on bone material from several archaeological sites in order to identify post-burial inclusions which, if present, may affect radiocarbon dating of bone. Two types of inclusions were identified: (1) precipitates from ground water solutions, and (2) solid intrusion. The first type consists of calcite, pyrite, humates and an unknown material. The second type includes quartz grains, hyphae, rootlets, wood and charcoal. Precipitation of calcite in a macro-molecular level in bone may lead to erroneaous dating of bone apatite if such calcite was not removed completely. A special technique, therefore, must be employed to remove calcite comletely. Hyphae and rootlets also are likely to induce errors in radiocarbon dating of bone collagen. These very fine inclusions require more than hand picking. (author)

Německý Mácha, Óda na radost a krize evropské vize

Czech Academy of Sciences Publication Activity Database

Pokorný, Martin Z.

2013-01-01

Roč. 31, 97-98 (2013), s. 244-251 ISSN 0862-7045 Institutional support: RVO:67985955 Keywords : K. H. Mácha * F. Schiller * A. Mozart * Enlightenment * romanticism Subject RIV: AA - Philosophy ; Religion

Atomic substitutions in synthetic apatite; Insights from solid-state NMR spectroscopy

Science.gov (United States)

Vaughn, John S.

Apatite, Ca5(PO4)3X (where X = F, Cl, or OH), is a unique mineral group capable of atomic substitutions for cations and anions of varied size and charge. Accommodation of differing substituents requires some kind of structural adaptation, e.g. new atomic positions, vacancies, or coupled substitutions. These structural adaptations often give rise to important physicochemical properties relevant to a range of scientific disciplines. Examples include volatile trapping during apatite crystallization, substitution for large radionuclides for long-term storage of nuclear fission waste, substitution for fluoride to improve acid resistivity in dental enamel composed dominantly of hydroxylapatite, and the development of novel biomaterials with enhanced biocompatibility. Despite the importance and ubiquity of atomic substitutions in apatite materials, many of the mechanisms by which these reactions occur are poorly understood. Presence of substituents at dilute concentration and occupancy of disordered atomic positions hinder detection by bulk characterization methods such as X-ray diffraction (XRD) and infrared (IR) spectroscopy. Solid-state nuclear magnetic resonance (NMR) spectroscopy is an isotope-specific structural characterization technique that does not require ordered atomic arrangements, and is therefore well suited to investigate atomic substitutions and structural adaptations in apatite. In the present work, solid-state NMR is utilized to investigate structural adaptations in three different types of apatite materials; a series of near-binary F, Cl apatite, carbonate-hydroxylapatite compositions prepared under various synthesis conditions, and a heat-treated hydroxylapatite enriched in 17O. The results indicate that hydroxyl groups in low-H, near binary F,Cl apatite facilitate solid-solution between F and Cl via column reversals, which result in average hexagonal symmetry despite very dilute OH concentration ( 2 mol percent). In addition, 19F NMR spectra indicate

Tissue reaction and material biodegradation of a calcium sulfate/apatite biphasic bone substitute in rat muscle

Directory of Open Access Journals (Sweden)

Jian-Sheng Wang

2016-07-01

Conclusion: Calcium sulfate hydroxyapatite bone substitute can be used as a carrier for antibiotics or other drugs, without adverse reaction due to the fast resorption of the calcium sulfate. No bone formation was seen despite treating the bone substitute with autologous bone marrow.

An investigation of fossil bone mineral structure with neutron scattering

International Nuclear Information System (INIS)

Batdehmbehrehl, G.; Chultehm, D.; Sangaa, D.

1999-01-01

Using the neutron diffraction method a domination of low crystal syngonic (sp. gr. P63/m) phase Ca 5 [PO 4 ] 3 (OH, F, Cl) in the fossil dinosaur bone has been established. It is shown that the neutron diffraction method has large advantages in apatite phase of any vertebrates studies and in the case of carbonate phase x-ray method it becomes to be preferable. (author)

Micro-distribution of uranium in bone after contamination: new insight into its mechanism of accumulation into bone tissue

Energy Technology Data Exchange (ETDEWEB)

Bourgeois, Damien [ICSM, LHYS, Bagnols-sur-Ceze (France); Burt-Pichat, Brigitte [INSERM, UMR 1033 Lyon (France); Lyon Univ. (France); Le Goff, Xavier [ICSM, L2ME, Bagnols-sur-Ceze (France)

2015-09-15

After internal contamination, uranium rapidly distributes in the body; up to 20 % of the initial dose is retained in the skeleton, where it remains for years. Several studies suggest that uranium has a deleterious effect on the bone cell system, but little is known regarding the mechanisms leading to accumulation of uranium in bone tissue. We have performed synchrotron radiation-based micro-X-ray fluorescence (SR μ-XRF) studies to assess the initial distribution of uranium within cortical and trabecular bones in contaminated rats' femurs at the micrometer scale. This sensitive technique with high spatial resolution is the only method available that can be successfully applied, given the small amount of uranium in bone tissue. Uranium was found preferentially located in calcifying zones in exposed rats and rapidly accumulates in the endosteal and periosteal area of femoral metaphyses, in calcifying cartilage and in recently formed bone tissue along trabecular bone. Furthermore, specific localized areas with high accumulation of uranium were observed in regions identified as micro-vessels and on bone trabeculae. These observations are of high importance in the study of the accumulation of uranium in bone tissue, as the generally proposed passive chemical sorption on the surface of the inorganic part (apatite) of bone tissue cannot account for these results. Our study opens original perspectives in the field of exogenous metal bio-mineralization.

Functional adaptation of long bone extremities involves the localized "tuning" of the cortical bone composition; evidence from Raman spectroscopy.

Science.gov (United States)

Buckley, Kevin; Kerns, Jemma G; Birch, Helen L; Gikas, Panagiotis D; Parker, Anthony W; Matousek, Pavel; Goodship, Allen E

2014-01-01

In long bones, the functional adaptation of shape and structure occurs along the whole length of the organ. This study explores the hypothesis that adaptation of bone composition is also site-specific and that the mineral-to-collagen ratio of bone (and, thus, its mechanical properties) varies along the organ's length. Raman spectroscopy was used to map the chemical composition of long bones along their entire length in fine spatial resolution (1 mm), and then biochemical analysis was used to measure the mineral, collagen, water, and sulfated glycosaminoglycan content where site-specific differences were seen. The results show that the mineral-to-collagen ratio of the bone material in human tibiae varies by 10% toward the flared extremities of the bone. Comparisons with long bones from other large animals (horses, sheep, and deer) gave similar results with bone material composition changing across tens of centimeters. The composition of the bone apatite also varied with the phosphate-to-carbonate ratio decreasing toward the ends of the tibia. The data highlight the complexity of adaptive changes and raise interesting questions about the biochemical control mechanisms involved. In addition to their biological interest, the data provide timely information to researchers developing Raman spectroscopy as a noninvasive tool for measuring bone composition in vivo (particularly with regard to sampling and measurement protocol).

Functional adaptation of long bone extremities involves the localized ``tuning'' of the cortical bone composition; evidence from Raman spectroscopy

Science.gov (United States)

Buckley, Kevin; Kerns, Jemma G.; Birch, Helen L.; Gikas, Panagiotis D.; Parker, Anthony W.; Matousek, Pavel; Goodship, Allen E.

2014-11-01

In long bones, the functional adaptation of shape and structure occurs along the whole length of the organ. This study explores the hypothesis that adaptation of bone composition is also site-specific and that the mineral-to-collagen ratio of bone (and, thus, its mechanical properties) varies along the organ's length. Raman spectroscopy was used to map the chemical composition of long bones along their entire length in fine spatial resolution (1 mm), and then biochemical analysis was used to measure the mineral, collagen, water, and sulfated glycosaminoglycan content where site-specific differences were seen. The results show that the mineral-to-collagen ratio of the bone material in human tibiae varies by 10% toward the flared extremities of the bone. Comparisons with long bones from other large animals (horses, sheep, and deer) gave similar results with bone material composition changing across tens of centimeters. The composition of the bone apatite also varied with the phosphate-to-carbonate ratio decreasing toward the ends of the tibia. The data highlight the complexity of adaptive changes and raise interesting questions about the biochemical control mechanisms involved. In addition to their biological interest, the data provide timely information to researchers developing Raman spectroscopy as a noninvasive tool for measuring bone composition in vivo (particularly with regard to sampling and measurement protocol).

Extracellular Protease of Pseudomonas fluorescens CHA0, a Biocontrol Factor with Activity against the Root-Knot Nematode Meloidogyne incognita

OpenAIRE

Siddiqui, Imran Ali; Haas, Dieter; Heeb, Stephan

2005-01-01

In Pseudomonas fluorescens CHA0, mutation of the GacA-controlled aprA gene (encoding the major extracellular protease) or the gacA regulatory gene resulted in reduced biocontrol activity against the root-knot nematode Meloidogyne incognita during tomato and soybean infection. Culture supernatants of strain CHA0 inhibited egg hatching and induced mortality of M. incognita juveniles more strongly than did supernatants of aprA and gacA mutants, suggesting that AprA protease contributes to biocon...

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

International Nuclear Information System (INIS)

Tisserand, R.

2004-12-01

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)

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.

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.

Composition dependent thermal annealing behaviour of ion tracks in apatite

Energy Technology Data Exchange (ETDEWEB)

Nadzri, A., E-mail: allina.nadzri@anu.edu.au [Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University, Canberra, ACT 2601 (Australia); Schauries, D.; Mota-Santiago, P.; Muradoglu, S. [Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University, Canberra, ACT 2601 (Australia); Trautmann, C. [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Technische Universität Darmstadt, 64287 Darmstadt (Germany); Gleadow, A.J.W. [School of Earth Science, University of Melbourne, Melbourne, VIC 3010 (Australia); Hawley, A. [Australian Synchrotron, 800 Blackburn Road, Clayton, VIC 3168 (Australia); Kluth, P. [Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University, Canberra, ACT 2601 (Australia)

2016-07-15

Natural apatite samples with different F/Cl content from a variety of geological locations (Durango, Mexico; Mud Tank, Australia; and Snarum, Norway) were irradiated with swift heavy ions to simulate fission tracks. The annealing kinetics of the resulting ion tracks was investigated using synchrotron-based small-angle X-ray scattering (SAXS) combined with ex situ annealing. The activation energies for track recrystallization were extracted and consistent with previous studies using track-etching, tracks in the chlorine-rich Snarum apatite are more resistant to annealing than in the other compositions.

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

International Nuclear Information System (INIS)

Naeser, C.W.; Crowley, K.D.

1990-01-01

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

Apatite layer growth on glassy Zr{sub 48}Cu{sub 36}Al{sub 8}Ag{sub 8} sputtered titanium for potential biomedical applications

Energy Technology Data Exchange (ETDEWEB)

Thanka Rajan, S.; Karthika, M. [Electrochemical Materials Science Division, CSIR-Central Electrochemical Research Institute, Karaikudi 630003 (India); Bendavid, Avi [Plasma Processing & Deposition Team, CSIRO Manufacturing Flagship, LindField, 2070, Sydney (Australia); Subramanian, B., E-mail: subramanianb3@gmail.com [Plasma Processing & Deposition Team, CSIRO Manufacturing Flagship, LindField, 2070, Sydney (Australia); Electrochemical Materials Science Division, CSIR-Central Electrochemical Research Institute, Karaikudi 630003 (India)

2016-04-30

Graphical abstract: - Highlights: • Metallic biomaterials are surface modified by Zr based TFMGs. • A bone-like apatite layer was grown on a Ni-free Zr-based TFMG in vitro. • Apatite layer growth confirmed by XRD and XPS analysis indicates its bioactivity. • Electrochemical response of the TFMGs in SBF possesses good corrosion resistance. - Abstract: The bioactivity of magnetron sputtered thin film metallic glasses (TFMGs) of Zr{sub 48}Cu{sub 36}Al{sub 8}Ag{sub 8} (at.%) on titanium substrates was tested for bio implant applications. The structural and elemental compositions of TFMGs were analyzed by XRD, XPS and EDAX. X-ray diffraction analysis displayed a broad hump around the incident angle of 30–50°, suggesting that the coatings possess a glassy structure. An in situ crystal growth of hydroxyapatite was observed by soaking the sputtered specimen in simulated body fluid (SBF). The nucleation and growth of a calcium phosphate (Ca–P) bone-like hydroxyapatite on Zr{sub 48}Cu{sub 36}Al{sub 8}Ag{sub 8} (at.%) TFMG from SBF was investigated by using XRD, AFM and SEM. The presence of calcium and phosphorus elements was confirmed by EDAX and XPS. In vitro electrochemical corrosion studies indicated that the Zr-based TFMG coating sustain in the stimulated body-fluid (SBF), exhibiting superior corrosion resistance with a lower corrosion penetration rate and electrochemical stability than the bare crystalline titanium substrate.

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

The value of the CHA2DS2-VASc score for refining stroke risk stratification in patients with atrial fibrillation with a CHADS2 score 0-1

DEFF Research Database (Denmark)

Olesen, Jonas Bjerring; Torp-Pedersen, Christian; Hansen, Morten Lock

2012-01-01

associated with increasing CHA2DS2-VASc score was estimated in Cox regression models adjusted for year of inclusion and antiplatelet therapy. The value of adding the extra CHA2DS2-VASc risk factors to the CHADS2 score was evaluated by c-statistics, Net Reclassification Improvement (NRI) and Integrated......DS2-VASc score significantly improved the predictive value of the CHADS2 score alone and a CHA2DS2-VASc score=0 could clearly identify 'truly low risk' subjects. Use of the CHA2DS2-VASc score would significantly improve classification of AF patients at low and intermediate risk of stroke, compared......North American and European guidelines on atrial fibrillation (AF) are conflicting regarding the classification of patients at low/intermediate risk of stroke. We aimed to investigate if the CHA2DS2-VASc score improved risk stratification of AF patients with a CHADS2 score of 0-1. Using individual...

Bioconversion of Agave tequilana fructans by exo-inulinases from indigenous Aspergillus niger CH-A-2010 enhances ethanol production from raw Agave tequilana juice.

Science.gov (United States)

Huitrón, Carlos; Pérez, Rosalba; Gutiérrez, Luís; Lappe, Patricia; Petrosyan, Pavel; Villegas, Jesús; Aguilar, Cecilia; Rocha-Zavaleta, Leticia; Blancas, Abel

2013-01-01

Agave tequilana fructans are the source of fermentable sugars for the production of tequila. Fructans are processed by acid hydrolysis or by cooking in ovens at high temperature. Enzymatic hydrolysis is considered an alternative for the bioconversion of fructans. We previously described the isolation of Aspergillus niger CH-A-2010, an indigenous strain that produces extracellular inulinases. Here we evaluated the potential application of A. niger CH-A-2010 inulinases for the bioconversion of A. tequilana fructans, and its impact on the production of ethanol. Inulinases were analyzed by Western blotting and thin layer chromatography. Optimal pH and temperature conditions for inulinase activity were determined. The efficiency of A. niger CH-A-2010 inulinases was compared with commercial enzymes and with acid hydrolysis. The hydrolysates obtained were subsequently fermented by Saccharomyces cerevisiae to determine the efficiency of ethanol production. Results indicate that A. niger CH-A-2010 predominantly produces an exo-inulinase activity. Optimal inulinase activity occurred at pH 5.0 and 50 °C. Hydrolysis of raw agave juice by CH-A-2010 inulinases yielded 33.5 g/l reducing sugars, compared with 27.3 g/l by Fructozyme(®) (Novozymes Corp, Bagsværd, Denmark) and 29.4 g/l by acid hydrolysis. After fermentation of hydrolysates, we observed that the conversion efficiency of sugars into ethanol was 97.5 % of the theoretical ethanol yield for enzymatically degraded agave juice, compared to 83.8 % for acid-hydrolyzed juice. These observations indicate that fructans from raw Agave tequilana juice can be efficiently hydrolyzed by using A. niger CH-A-2010 inulinases, and that this procedure impacts positively on the production of ethanol.

AN INVESTIGATION OF THE MINERAL IN DUCTILE AND BRITTLE CORTICAL MOUSE BONE

Science.gov (United States)

Rodriguez-Florez, Naiara; Garcia-Tunon, Esther; Mukadam, Quresh; Saiz, Eduardo; Oldknow, Karla J.; Farquharson, Colin; Millán, José Luis; Boyde, Alan; Shefelbine, Sandra J.

2015-01-01

Bone is a strong and tough material composed of apatite mineral, organic matter and water. Changes in composition and organization of these building blocks affect bone’s mechanical integrity. Skeletal disorders often affect bone’s mineral phase, either by variations in the collagen or directly altering mineralization. The aim of the current study was to explore the differences in the mineral of brittle and ductile cortical bone at the mineral (nm) and tissue (µm) levels using two mouse phenotypes. Osteogenesis imperfecta murine (oim−/−) mice were used to model brittle bone; PHOSPHO1 mutants (Phospho1−/−) had ductile bone. They were compared to their respective wild-type controls. Femora were defatted and ground to powder to measure average mineral crystal size using X-ray diffraction (XRD), and to monitor the bulk mineral to matrix ratio via thermogravimetric analysis (TGA). XRD scans were run after TGA for phase identification, to assess the fractions of hydroxyapatite and β-tricalcium phosphate. Tibiae were embedded to measure elastic properties with nanoindentation and the extent of mineralization with backscattered electron microscopy (qbSEM). Interestingly, the mineral of brittle oim−/− and ductile Phospho1−/− bones had many similar characteristics. Both pathology models had smaller apatite crystals, lower mineral to matrix ratio, and showed more thermal conversion to β-tricalcium phosphate than their wild-types, indicating deviations from stoichiometric hydroxyapatite in the original mineral. The degree of mineralization of the bone matrix was different for each strain: oim−/− were hypermineralized, while Phospho1−/− were hypomineralized. However, alterations in the mineral were associated with reduced tissue elastic moduli in both pathologies. Results revealed that despite having extremely different whole bone mechanics, the mineral of oim−/− and Phospho1−/− has several similar trends at smaller length scales. This

Crystal growth of carbonate apatite using a CaCO3 flux.

Science.gov (United States)

Suetsugu, Y; Tanaka, J

1999-09-01

Single crystals of carbonate apatite were grown using a CaCO3 flux under an Ar gas pressure of 55 MPa. The crystals obtained were observed by scanning electron microscopy, optical microscopy and X-ray diffraction. Electron probe microanalyses and thermal analyses were performed. CO3 ions in planar triangle form replaced both OH sites and PO4 tetrahedral sites in the apatite structure: in particular, the OH sites were perfectly substituted by CO3 ions using this method.

Chaîne de blocs | CRDI - Centre de recherches pour le ...

International Development Research Centre (IDRC) Digital Library (Canada)

7 déc. 2017 ... Des édutiants dans une salle de classe, Tambon Mae La, Myanmar. Zi Jian Lim. La technologie des chaînes de blocs pourrait appuyer et améliorer la gouvernance démocratique et les programmes de développement, mais le degré élevé de sophistication et les exigences complexes du point de vue de ...

Platelet-rich fibrin in the treatment of periodontal bone defects.

Science.gov (United States)

Ranganathan, Aravindhan T; Chandran, Chitraa R

2014-05-01

Periodontitis is characterized by the formation of true pockets, bone loss and attachment loss. Various techniques have been attempted in the past to truly regenerate the lost periodontal structures, albeit with variable outcome. In this evolution, the technique being tried out widely is the use of platelet rich concentrates, namely platelet-rich fibrin (PRF). In this report, we present a case of surgical treatment of osseous bone defects namely two walled crater and dehiscence treated in posterior teeth with autologously prepared platelet rich fibrin mixed with hydroxy apatite bone graft and PRF in the form of a membrane. Our results showed clinical improvements in all the clinical parameters postoperatively namely the pocket depth reduction and gain in attachment level and hence, PRF can be used alone or in combination with the bone graft to yield successful clinical results in treating periodontal osseous defects. Platelet-rich fibrin is an effective alternative to platelet-rich plasma (PRP) in reconstructing bone defects.

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

The relationship between fission track length and track density in apatite

International Nuclear Information System (INIS)

Laslett, G.M.; Gleadow, A.J.W.; Duddy, I.R.

1984-01-01

Fission track dating is based upon an age equation derived from a random line segment model for fission tracks. This equation contains the implicit assumption of a proportional relationship between the true mean length of fission tracks and their track density in an isotropic medium. Previous experimental investigation of this relationship for both spontaneous and induced tracks in apatite during progressive annealment model in an obvious fashion. Corrected equations relating track length and density for apatite, an anisotropic mineral, show that the proportionality in this case is between track density and a length factor which is a generalization of the mean track length combining the actual length and crystallographic orientation of the track. This relationship has been experimentally confirmed for induced tracks in Durango apatite, taking into account bias in sampling of the track lengths, and the effect of the bulk etching velocity. (author)

Extracellular Protease of Pseudomonas fluorescens CHA0, a Biocontrol Factor with Activity against the Root-Knot Nematode Meloidogyne incognita

Science.gov (United States)

Siddiqui, Imran Ali; Haas, Dieter; Heeb, Stephan

2005-01-01

In Pseudomonas fluorescens CHA0, mutation of the GacA-controlled aprA gene (encoding the major extracellular protease) or the gacA regulatory gene resulted in reduced biocontrol activity against the root-knot nematode Meloidogyne incognita during tomato and soybean infection. Culture supernatants of strain CHA0 inhibited egg hatching and induced mortality of M. incognita juveniles more strongly than did supernatants of aprA and gacA mutants, suggesting that AprA protease contributes to biocontrol. PMID:16151170

The Chaîne des Puys: how complicated can monogentic get?

Science.gov (United States)

Van Wyk de Vries, B.; Grosse, P.; Marquez, A.; Petronis, M. S.; Kervyn, M.; Delcamp, A.; Mossoux, S.; Troll, V. R.

2012-12-01

The Chaîne des Puys (Massif Centrale of France) is part of a prospective volcano-tectonic UNESCO World Heritage site including the Limagne Rift fault (http://www.chainedespuys-failledelimagne.com/). The strategy is to present the monogentic field that is as representative of other such fields, but which itself is uniquely special. Effectively, the Chaîne des Puys would become a sort of ambassador for monogentic volcanism, raising the profile of all other sites. Here, I want to go through some recent work on the chain, looking at morphology, morphometry, structure, lithology and petrology and show some of the intriguing complexities of this classic highly variable monogentic alignment. Also, I want to build on the historical development of ideas that can be traced back to characters such as Montlosier, Humphrey Davey, Faraday, Lyell, and Von Humbolt... and many more. I focus, first, on the central the Puy de Dôme. This classic trachyte dome has been known for some time to be the product of two eruptions, and recently we have found that it is related to a number of cryptodome intrusions that have created flanking bulges, fed at least two major explosive eruptions, and extensively modified the topography of the field. Strangely, Von Humbolt's concept of 'craters of elevation' rises up in a reanalysis of these structures. Secondly, I visit Lemptégy (www.auvergne-volcan.com/), that in 1857, Scrope called 'an insignificant cone grazed by sheep', but now quarried out and showing the internal structure expected for the Puy de Dôme bulges, as well as illustrating that a seemingly simple scoria cone plumbing can be infernally complicated. Thirdly, I consider the Beaunit, a bucolic village in a maar, where the process of crustal ingestion suggests an intimate relationship between eruptive dynamics and assimilation. With these three examples I show some of the complications and interactions of monogentic basaltic to trachytic volcanism typified by the Chaîne des Puys.

Theoretical basis of remediation of heavy metal contamination by apatite

International Nuclear Information System (INIS)

Raicevic, S.; Mandic, M.; Kaludjerovic, T.

2001-01-01

Recently we have demonstrated the connection between stability of the products of the in situ remediation processes and their values of the ion-ion interaction potential, representing the main term of the cohesive energy. Using this approach, the stability of the products of remediation of Pb and Cd by hydroxyapatite (HAP) was investigated. It has been demonstrated that incorporation of Pb ions from pyromorphite into HAP is followed by a decrease of the cohesive energy, indicating that in remediation of Pb, HAP serves as a source of components necessary for formation of a stabile Pb-apatite phase which is precipitated on the surface of the HAP particles. Contrary, incorporation of Cd from the Cd-apatite into HAP increases the cohesive energy of the system, suggesting that the precipitated Cd-apatite phase is later transformed into a more stabile HAP/Cd solid solution. The presented results of theoretical analysis are in good accordance with the reported experimental results. Based on the results of this analysis, the general criterion for estimation of stability of the products of the in situ remediation processes was proposed. (author)

Mechanochemical synthesis evaluation of nanocrystalline bone-derived bioceramic powder using for bone tissue engineering

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Amirsalar Khandan

2014-01-01

Full Text Available Introduction: Bone tissue engineering proposes a suitable way to regenerate lost bones. Different materials have been considered for use in bone tissue engineering. Hydroxyapatite (HA is a significant success of bioceramics as a bone tissue repairing biomaterial. Among different bioceramic materials, recent interest has been risen on fluorinated hydroxyapatites, (FHA, Ca 10 (PO 4 6 F x (OH 2−x . Fluorine ions can promote apatite formation and improve the stability of HA in the biological environments. Therefore, they have been developed for bone tissue engineering. The aim of this study was to synthesize and characterize the FHA nanopowder via mechanochemical (MC methods. Materials and Methods: Natural hydroxyapatite (NHA 95.7 wt.% and calcium fluoride (CaF 2 powder 4.3 wt.% were used for synthesis of FHA. MC reaction was performed in the planetary milling balls using a porcelain cup and alumina balls. Ratio of balls to reactant materials was 15:1 at 400 rpm rotation speed. The structures of the powdered particles formed at different milling times were evaluated by X-ray diffraction (XRD, scanning electron microscopy (SEM and transmission electron microscopy (TEM. Results: Fabrication of FHA from natural sources like bovine bone achieved after 8 h ball milling with pure nanopowder. Conclusion: F− ion enhances the crystallization and mechanical properties of HA in formation of bone. The produced FHA was in nano-scale, and its crystal size was about 80-90 nm with sphere distribution in shape and size. FHA powder is a suitable biomaterial for bone tissue engineering.

Fabrication of carbonate apatite block based on internal dissolution-precipitation reaction of dicalcium phosphate and calcium carbonate.

Science.gov (United States)

Daitou, Fumikazu; Maruta, Michito; Kawachi, Giichiro; Tsuru, Kanji; Matsuya, Shigeki; Terada, Yoshihiro; Ishikawa, Kunio

2010-05-01

In this study, we investigated a novel method for fabrication of carbonate apatite block without ionic movement between precursor and solution by using precursor that includes all constituent ions of carbonate apatite. A powder mixture prepared from dicalcium phosphate anhydrous and calcite at appropriate Ca/P ratios (1.5, 1.67, and 1.8) was used as starting material. For preparation of specimens, the slurry made from the powder mixture and distilled water was packed in a split stainless steel mold and heat - treated, ranging from 60 degrees C to 100 degrees C up to 48 hours at 100% humidity. It appeared that carbonate apatite could be obtained above 70 degrees C and monophasic carbonate apatite could be obtained from the powder mixture at Ca/P ratio of 1.67. Carbonate content of the specimen was about 5-7%. Diametral tensile strength of the carbonate apatite blocks slightly decreased with increasing treatment temperature. The decrease in diametral tensile strength is thought to be related to the crystal size of the carbonate apatite formed.

Mineralization of Synthetic Polymer Scaffolds: A Bottom-upApproach for the Development of Artificial Bone

Energy Technology Data Exchange (ETDEWEB)

Song, Jie; Viengkham, Malathong; Bertozzi, Carolyn R.

2004-09-27

The controlled integration of organic and inorganic components confers natural bone with superior mechanical properties. Bone biogenesis is thought to occur by templated mineralization of hard apatite crystals by an elastic protein scaffold, a process we sought to emulate with synthetic biomimetic hydrogel polymers. Crosslinked polymethacrylamide and polymethacrylate hydrogels were functionalized with mineral-binding ligands and used to template the formation of hydroxyapatite. Strong adhesion between the organic and inorganic materials was achieved for hydrogels functionalized with either carboxylate or hydroxy ligands. The mineral-nucleating potential of hydroxyl groups identified here broadens the design parameters for synthetic bone-like composites and suggests a potential role for hydroxylated collagen proteins in bone mineralization.

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

International Nuclear Information System (INIS)

Oliva, Josep; De Pablo, Joan; Cortina, Jose-Luis; Cama, Jordi; Ayora, Carlos

2011-01-01

Highlights: → The efficiency of Apatite II TM 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 II TM . → Compared with other reactive materials such as limestone and caustic magnesia that exhibit a reduction of porosity Apatite II TM showed stable hydraulic performance. → The extrapolation of the column durabilities to a 1-m-thick passive treatment suggests that the Apatite II TM filling can be active between 5 and 10 years for an inflow pH exceeding 5. - Abstract: Apatite II TM , a biogenic hydroxyapatite, was evaluated as a reactive material for heavy metal (Cd, Cu, Co, Ni and Hg) removal in passive treatments. Apatite II TM 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. Cd 5 (PO 4 ) 3 OH(s), Cu 2 (PO 4 )OH(s), Ni 3 (PO 4 ) 2 (s), Co 3 (PO 4 ) 2 8H 2 O(s) and Hg 3 (PO 4 ) 2 (s) are proposed as the possible mineral phases responsible for the removal processes. The results of the column experiments show that Apatite II TM is a suitable filling for permeable

La chaîne du froid en agroalimentaire

OpenAIRE

Rosset , Philippe; Beaufort , Annie; Cornu , Marie; Poumeyrol , Gérard

2002-01-01

Le recours au froid constitue une pratique courante pour assurer une conservation prolongée des aliments, de quelques jours à quelques semaines. Limitant notre propos aux denrées réfrigérées et au risque sanitaire d'origine microbiologique, après un rappel de la définition de la chaîne du froid et des modalités générales de mise en oeuvre, nous aborderons dans un premier temps les particularités technologiques de son application. Celle-ci sera étudiée tout d'abord selon le type d'aliments con...

Period changes of cataclysmic variables below the period gap: V2051 Oph, OY Car and Z Cha

Science.gov (United States)

Pilarčík, L.; Wolf, M.; Zasche, P.; Vraštil, J.

2018-04-01

We present our results of a long-term monitoring of cataclysmic variable stars (CVs). About 40 new eclipses were measured for the three southern SU UMa-type eclipsing CVs: V2051 Oph, OY Car and Z Cha. Based on the current O - C diagrams we confirmed earlier findings that V2051 Oph and OY Car present cyclic changes of their orbital periods lasting 25 and 29 years, respectively. In case of Z Cha we propose the light-time effect caused probably by a presence of the third component orbiting the eclipsing CV with the period of 43.5 years. The minimal mass of this companion results about 15 MJup.

Rheological, biocompatibility and osteogenesis assessment of fish collagen scaffold for bone tissue engineering.

Science.gov (United States)

Elango, Jeevithan; Zhang, Jingyi; Bao, Bin; Palaniyandi, Krishnamoorthy; Wang, Shujun; Wenhui, Wu; Robinson, Jeya Shakila

2016-10-01

In the present investigation, an attempt was made to find an alternative to mammalian collagen with better osteogenesis ability. Three types of collagen scaffolds - collagen, collagen-chitosan (CCH), and collagen-hydroxyapatite (CHA) - were prepared from the cartilage of Blue shark and investigated for their physico-functional and mechanical properties in relation to biocompatibility and osteogenesis. CCH scaffold was superior with pH 4.5-4.9 and viscosity 9.7-10.9cP. Notably, addition of chitosan and HA (hydroxyapatite) improved the stiffness (11-23MPa) and degradation rate but lowered the water binding capacity and porosity of the scaffold. Interestingly, CCH scaffolds remained for 3days before complete in-vitro biodegradation. The decreased amount of viable T-cells and higher level of FAS/APO-1 were substantiated the biocompatibility properties of prepared collagen scaffolds. Osteogenesis study revealed that the addition of CH and HA in both fish and mammalian collagen scaffolds could efficiently promote osteoblast cell formation. The ALP activity was significantly high in CHA scaffold-treated osteoblast cells, which suggests an enhanced bone-healing process. Therefore, the present study concludes that the composite scaffolds prepared from fish collagen with higher stiffness, lower biodegradation rate, better biocompatible, and osteogenesis properties were suitable biomaterial for a bone tissue engineering application as an alternative to mammalian collagen scaffolds. Copyright © 2016 Elsevier B.V. All rights reserved.

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

International Nuclear Information System (INIS)

Audubert, F.

1995-01-01

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 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 2 with a Pb 3 (VO 4 ) 1.6 (PO 4 ) 0.4 layer and a Ca 10 (PO 4 ) 6 F 2 layer. Sintering is performed at 700 deg. celsius under a 25 MPa pressure. (J.S.)

Physico-chemical and thermochemical studies of the hydrolytic conversion of amorphous tricalcium phosphate into apatite

International Nuclear Information System (INIS)

Somrani, Saida; Banu, Mihai; Jemal, Mohamed; Rey, Christian

2005-01-01

The conversion of amorphous tricalcium phosphate with different hydration ratio into apatite in water at 25 deg. C has been studied by microcalorimetry and several physical-chemical methods. The hydrolytic transformation was dominated by two strong exothermic events. A fast, relatively weak, wetting process and a very slow but strong heat release assigned to a slow internal rehydration and the crystallization of the amorphous phase into an apatite. The exothermic phenomenon related to the rehydration exceeded the crystalline transformation enthalpy. Rehydration occurred before the conversion of the amorphous phase into apatite and determined the advancement of the hydrolytic reaction. The apatitic phases formed evolved slightly with time after their formation. The crystallinity increased whereas the amount of HPO 4 2- ion decreased. These data allow a better understanding of the behavior of biomaterials involving amorphous phases such as hydroxyapatite plasma-sprayed coatings

Nanoporous Structure of Bone Matrix at Osteoporosis from Data of Atomic Force Microscopy and IR Spectroscopy

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A. A. Gaidash

2011-01-01

Full Text Available It was found that in an osteoporotic bone the fraction of nanosized pores decreases, the mineral phase amorphizes, hydrated shells around mineralized particles of the bone matrix thicken, and adhesion forces increase. This contributes to the formation of water clusters similar to bulk water clusters compared to the healthy bone tissue and leads to the accumulation of more viscous liquid with increased intermolecular interaction forces in the pores of the bone matrix. Given this, the rates of chemical reactions proceeding in the water phase of ultrathin channels of general parts of collagen fibrils decrease. Ultimately, nanopores of collagen-apatite interfaces lose, to a certain extent, the capability of catalyzing the hydroxyapatite crystallization.

A paradigm shift for bone quality in dentistry: A literature review.

Science.gov (United States)

Kuroshima, Shinichiro; Kaku, Masaru; Ishimoto, Takuya; Sasaki, Muneteru; Nakano, Takayoshi; Sawase, Takashi

2017-10-01

The aim of this study was to present the current concept of bone quality based on the proposal by the National Institutes of Health (NIH) and some of the cellular and molecular factors that affect bone quality. This is a literature review which focuses on collagen, biological apatite (BAp), and bone cells such as osteoblasts and osteocytes. In dentistry, the term "bone quality" has long been considered to be synonymous with bone mineral density (BMD) based on radiographic and sensible evaluations. In 2000, the NIH proposed the concept of bone quality as "the sum of all characteristics of bone that influence the bone's resistance to fracture," which is completely independent of BMD. The NIH defines bone quality as comprising bone architecture, bone turnover, bone mineralization, and micro-damage accumulation. Moreover, our investigations have demonstrated that BAp, collagen, and bone cells such as osteoblasts and osteocytes play essential roles in controlling the current concept of bone quality in bone around hip and dental implants. The current concept of bone quality is crucial for understanding bone mechanical functions. BAp, collagen and osteocytes are the main factors affecting bone quality. Moreover, mechanical loading dynamically adapts bone quality. Understanding the current concept of bone quality is required in dentistry. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Synthesis and characterization of pure strontium apatite particles and nanoporous scaffold prepared by dextrose-templated method

Science.gov (United States)

Ma, Xiaoyu; Liu, Yongjia; Zhu, Bangshang

2018-02-01

Strontium shows an increasing interest on bone formation and bone resorption prevention. Here, pure apatite strontium (Ap-SrOH) [Sr5(PO4)3(OH), strontium hydroxyapatite] particles were prepared by the precipitation method using Sr(NO3)2 · 6H2O and (NH4)2HPO4 as reagents. Scanning electron microscope, transmission electron microscope combined with electron diffraction, X-ray diffraction, Fourier transform infrared spectra (FTIR), variable temperature FTIR and thermo gravimetric analysis were employed to evaluate the crystalline structure, chemical composition, and thermal stability of the Ap-SrOH particles. The results show that phase pure Ap-SrOH particles were prepared by wet precipitation. The obtained Ap-SrOH particles are single crystal in phase structure, they have hexagonal fusiform shape, and their size is about 30-180 nm in diameter, and 0.4-2.5 μm in length. The cell MTT assay evaluations indicate that Ap-SrOH particles have very low cytotoxicity. Furthermore, nanoporous Ap-SrOH scaffolds were synthesized by anhydrous dextrose template method. After mixed 5-10 wt% of anhydrous dextrose with Ap-SrOH particles, pressed into discs, and sintered in microwave muffle furnace at 600 °C, the scaffolds with both nanoporous and nanotopography were formed. Cell culture of MC3T3-E1 osteoblasts in vitro show cells grow well on nanoporous Ap-SrOH scaffold. Therefore, Ap-SrOH particles and their nanoporous scaffolds are promising biomaterials for bone repairing and bone disease (e.g. osteoporosis) healing.

Human bone marrow stem cell-encapsulating calcium phosphate scaffolds for bone repair

Science.gov (United States)

Weir, Michael D.; Xu, Hockin H.K.

2010-01-01

Due to its injectability and excellent osteoconductivity, calcium phosphate cement (CPC) is highly promising for orthopedic applications. However, a literature search revealed no report on human bone marrow mesenchymal stem cell (hBMSC) encapsulation in CPC for bone tissue engineering. The aim of this study was to encapsulate hBMSCs in alginate hydrogel beads and then incorporate them into CPC, CPC–chitosan and CPC–chitosan–fiber scaffolds. Chitosan and degradable fibers were used to mechanically reinforce the scaffolds. After 21 days, that the percentage of live cells and the cell density of hBMSCs inside CPC-based constructs matched those in alginate without CPC, indicating that the CPC setting reaction did not harm the hBMSCs. Alkaline phosphate activity increased by 8-fold after 14 days. Mineral staining, scanning electron microscopy and X-ray diffraction confirmed that apatitic mineral was deposited by the cells. The amount of hBMSC-synthesized mineral in CPC–chitosan–fiber matched that in CPC without chitosan and fibers. Hence, adding chitosan and fibers, which reinforced the CPC, did not compromise hBMSC osteodifferentiation and mineral synthesis. In conclusion, hBMSCs were encapsulated in CPC and CPC–chitosan–fiber scaffolds for the first time. The encapsulated cells remained viable, osteodifferentiated and synthesized bone minerals. These self-setting, hBMSC-encapsulating CPC-based constructs may be promising for bone tissue engineering applications. PMID:20451676

Biomimetic nanoclay scaffolds for bone tissue engineering

Science.gov (United States)

Ambre, Avinash Harishchandra

Tissue engineering offers a significant potential alternative to conventional methods for rectifying tissue defects by evoking natural regeneration process via interactions between cells and 3D porous scaffolds. Imparting adequate mechanical properties to biodegradable scaffolds for bone tissue engineering is an important challenge and extends from molecular to macroscale. This work focuses on the use of sodium montmorillonite (Na-MMT) to design polymer composite scaffolds having enhanced mechanical properties along with multiple interdependent properties. Materials design beginning at the molecular level was used in which Na-MMT clay was modified with three different unnatural amino acids and further characterized using Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD). Based on improved bicompatibility with human osteoblasts (bone cells) and intermediate increase in d-spacing of MMT clay (shown by XRD), 5-aminovaleric acid modified clay was further used to prepare biopolymer (chitosan-polygalacturonic acid complex) scaffolds. Osteoblast proliferation in biopolymer scaffolds containing 5-aminovaleric acid modified clay was similar to biopolymer scaffolds containing hydroxyapatite (HAP). A novel process based on biomineralization in bone was designed to prepare 5-aminovaleric acid modified clay capable of imparting multiple properties to the scaffolds. Bone-like apatite was mineralized in modified clay and a novel nanoclay-HAP hybrid (in situ HAPclay) was obtained. FTIR spectroscopy indicated a molecular level organic-inorganic association between the intercalated 5-aminovaleric acid and mineralized HAP. Osteoblasts formed clusters on biopolymer composite films prepared with different weight percent compositions of in situ HAPclay. Human MSCs formed mineralized nodules on composite films and mineralized extracellular matrix (ECM) in composite scaffolds without the use of osteogenic supplements. Polycaprolactone (PCL), a synthetic polymer, was

Impact of biocontrol Pseudomonas fluorescens CHA0 and a genetically modified derivative on the diversity of culturable fungi in the cucumber rhizosphere.

Science.gov (United States)

Girlanda, M; Perotto, S; Moenne-Loccoz, Y; Bergero, R; Lazzari, A; Defago, G; Bonfante, P; Luppi, A M

2001-04-01

Little is known about the effects of Pseudomonas biocontrol inoculants on nontarget rhizosphere fungi. This issue was addressed using the biocontrol agent Pseudomonas fluorescens CHA0-Rif, which produces the antimicrobial polyketides 2,4-diacetylphloroglucinol (Phl) and pyoluteorin (Plt) and protects cucumber from several fungal pathogens, including Pythium spp., as well as the genetically modified derivative CHA0-Rif(pME3424). Strain CHA0-Rif(pME3424) overproduces Phl and Plt and displays improved biocontrol efficacy compared with CHA0-Rif. Cucumber was grown repeatedly in the same soil, which was left uninoculated, was inoculated with CHA0-Rif or CHA0-Rif(pME3424), or was treated with the fungicide metalaxyl (Ridomil). Treatments were applied to soil at the start of each 32-day-long cucumber growth cycle, and their effects on the diversity of the rhizosphere populations of culturable fungi were assessed at the end of the first and fifth cycles. Over 11,000 colonies were studied and assigned to 105 fungal species (plus several sterile morphotypes). The most frequently isolated fungal species (mainly belonging to the genera Paecilomyces, Phialocephala, Fusarium, Gliocladium, Penicillium, Mortierella, Verticillium, Trichoderma, Staphylotrichum, Coniothyrium, Cylindrocarpon, Myrothecium, and Monocillium) were common in the four treatments, and no fungal species was totally suppressed or found exclusively following one particular treatment. However, in each of the two growth cycles studied, significant differences were found between treatments (e.g., between the control and the other treatments and/or between the two inoculation treatments) using discriminant analysis. Despite these differences in the composition and/or relative abundance of species in the fungal community, treatments had no effect on species diversity indices, and species abundance distributions fit the truncated lognormal function in most cases. In addition, the impact of treatments at the 32-day

Association of epicardial adipose tissue thickness and inflammation parameters with CHA2DS2-VASc score in patients with nonvalvular atrial fibrillation

Directory of Open Access Journals (Sweden)

Akdag S

2015-11-01

Full Text Available Serkan Akdag, Hakki Simsek, Musa Sahin, Aytac Akyol, Ramazan Duz, Naci Babat Department of Cardiology, Yuzuncu Yil University Medical Faculty, Van, Turkey Background: Epicardial adipose tissue (EAT, mean platelet volume (MPV, platelet-to- lymphocyte ratio (PLR, and neutrophil-to-lymphocyte ratio (NLR have been shown to be helpful in predicting adverse cardiovascular events. However, to date, in the literature, there have been no studies demonstrating the relationship between EAT, MPV, PLR, NLR, and thromboembolism risk in atrial fibrillation (AF. Therefore, we examined the relationship between EAT, MPV, PLR, NLR, and CHA2DS2-VASc score used for the evaluation of thromboembolism risk in patients with AF.Methods: The study included 96 consecutive patients with AF and 52 age- and sex-matched control subjects. We calculated CHA2DS2-VASc risk score for each patient and measured baseline EAT thickness, MPV, PLR, NLR, left atrial volume index, and left ventricular ejection fraction.Results: The group with high CHA2DS2-VASc score had higher EAT (7.2±1.5 vs 5.9±1.2 mm, P<0.001, MPV (9.1±1.1 vs 8.4±1.0 fL, P=0.004, PLR (152.3±28.4 vs 126.7±25.4, P=0.001, and NLR (4.0±1.6 vs 3.2±1.3, P<0.001 compared to group with low-intermediate CHA2DS2-VASc score. Moreover, CHA2DS2-VASc score was found to be positively correlated with EAT (r=0.623, P<0.001, MPV (r=0.350, P=0.004, PLR (r=0.398, P=0.001, and NLR (r=0.518, P<0.001.Conclusion: Our study results demonstrated that EAT thickness, MPV, PLR, and NLR were associated with the thromboembolic risk exhibited by CHA2DS2-VASc score in patients with nonvalvular AF. Keywords: atrial fibrillation, epicardial adipose tissue, platelet, neutrophil, mean platelet volume

Early effect of platelet-rich plasma on bone healing in combination with an osteoconductive material in rat cranial defects.

NARCIS (Netherlands)

Plachokova, A.S.; Dolder, J. van den; Stoelinga, P.J.W.; Jansen, J.A.

2007-01-01

OBJECTIVE: The early effect of platelet-rich plasma (PRP) on bone regeneration in combination with dense biphasic hydroxyl apatite (HA)/beta-tricalcium phosphate (TCP) particles (ratio 60%/40%) was evaluated in rat cranial defects with a diameter of 6.2 mm. We hypothesize that PRP exerts its

Quantitative analysis from limited sampling: influence of the chemical composition of apatites on their resistance to irradiation damage

International Nuclear Information System (INIS)

Ribet, I.; Petit, J.C.; CEA Cadarache, 13 - Saint-Paul-lez-Durance

1998-01-01

Apatites are investigated as possible high performance radioactive waste matrices for specific actinides. In this paper, we have quantified the influence of the chemical composition of apatites on their fission-track annealing behaviour. We aimed to evaluate the capability of apatites to self-anneal high densities of radiation damages produced during disposal. The thermal annealing kinetics, at 280 deg. C, of induced fission tracks has been determined for six different apatite compositions. We show that the chemical composition of apatites is a critical parameter with respect to their annealing behaviour. A mathematical treatment of the data, based upon the methodology of optimum design of experiments, allowed the quantification of the role of substitution for two major elements, of the apatite structure (Ca, P), for chlorine and for the two groups of minor elements, actinides (U+Th) and lanthanides (La+Ce+Y), which are relevant in the nuclear waste disposal context. A high actinide content enhances the annealing of fission-tracks in apatites, which is a very favourable feature of these minerals as radioactive waste matrices. This work also points to a new strategy for the best use of information provided by geological samples. In particular, the mathematical methodology proposed here allows, first, to evaluate the 'quality' of the information obtained and, second, to improve it by a proper choice of additional samples to investigate. (authors)

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

International Nuclear Information System (INIS)

Marshallsea, S.J.

1987-01-01

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

Sulfur concentration and isotopic variation in apatites from granitic to granodioritic plutons of a Cretaceous Cordilleran Batholith

Science.gov (United States)

Economos, R. C.

2012-12-01

Apatite is a common igneous accessory mineral with a high saturation temperature which can therefore crystallize over a significant portion of magmatic compositional space. Sulfur presents an opportunity to identify zoning in apatites. Unlike other trace elements, sulfur is relatively immobile in the apatite crystal structure and can be present in typical concentrations up to 1500 - 2000 ppm (or 0.5 to 1 wt% SO3). Sulfur concentration zoning in igneous apatites from ore producing magmatic systems has been identified (Streck and Dilles, 1998), but the interpretation of the cause of this zoning remains an open question. δ34S isotopic ratios of whole apatites have been used to track isotopic evolution associated with changes in magma fO2 and eruptive degassing (Rye, 2005). The presented work combines sulfur concentration mapping in zoned apatite crystals with in-situ SIMS 34S and 32S isotope measurements. Apatites were extracted from granite to granodiorite samples from the Cadiz Valley Batholith in the central Mojave Desert. This batholith is related to the pulse of Cretaceous Cordilleran magmatism that generated large batholiths in the Sierra Nevada and the Penninsular Ranges. The Mojave segment of the Cretaceous arc is unique in their construction into a full thickness of continental crust which exerted a strong influence on magmatic compositions. Apatite grains were mounted parallel to C axes, ground until grains were approximately bisected, and analyzed by Electron Microprobe at UCLA, for CaO, P2O5, SO3 and SiO2. Grains were surveyed and those yielding anomalous SO3 contents were investigated by micron-scale concentration mapping. Typical SO3 concentrations of apatites from all samples were ~0.2 wt%, while 8 to 10% of apatite grains from two samples contained cores with concentrations ranging up to 0.5 wt%. The sulfur zoning in these samples is oscillatory, in some grains representing 5 to 6 repetitions of high and low concentrations. Based on these textures

Effects of Metal Ions on the Flotation of Apatite, Dolomite and Quartz

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Yaoyang Ruan

2018-04-01

Full Text Available The effects of Ca2+, Mg2+, Al3+, and Fe3+ on the flotation behaviors of apatite, dolomite and quartz were investigated through a micro-flotation test, and the influence of calcium ions on the flotation of these minerals was further elucidated by solution chemistry study, zeta potential measurement, and X-ray photoelectron spectroscopy (XPS analyses. The results indicate that an appropriate amount of Ca2+ and Mg2+ can improve the floatability of apatite but had a negligible effect on the flotation performance of dolomite, whereas Al3+, Fe3+, and excessive amounts of Ca2+ decreased the recovery of apatite and dolomite. The studied metal cations can activate quartz at a particular pH. It can be inferred from solution chemistry and zeta potential measurement that the influence of metal ions on the flotation of different minerals should be attributed to the adsorption of various hydrolysis species on the mineral surfaces. XPS analyses reveal that calcium ions can enhance the adsorption of anionic collector on apatite and quartz surfaces, and there are no apparent changes to be observed on the surface of dolomite in the absence and presence of calcium ions at a concentration of 2.5 × 10−3 M, which was in good agreement with the micro-flotation results.

Assessment of CHADS2 and CHA 2DS 2-VASc scores in obstructive sleep apnea patients with atrial fibrillation.

Science.gov (United States)

Szymanski, Filip M; Filipiak, Krzysztof J; Platek, Anna E; Hrynkiewicz-Szymanska, Anna; Karpinski, Grzegorz; Opolski, Grzegorz

2015-05-01

Assessment of stroke risk and implementation of appropriate antithrombotic therapy is an important issue in atrial fibrillation patients. Current risk scores do not take into consideration the comorbidities associated with elevated thromboembolic like obstructive sleep apnea (OSA). The aim of the study was to establish whether atrial fibrillation patients with coexisting OSA have higher stroke risk according to CHADS2 and CHA2DS2-VASc scores. Two hundred fifty-four consecutive patients hospitalized with a primary diagnosis of atrial fibrillation participated in the study. All patients underwent whole night polygraphy and were scored in both CHADS2 and CHA2DS2-VASc according to their medical records or de novo diagnosis. The study population was predominantly male (65.4%; mean age, 57.5 ± 10.0 years) with a high prevalence of hypertension (73.6%), dyslipidemia (63.4%), and obesity (42.9%). OSA was present in 47.6% of patients, who more often had history of stroke (p = 0.0007). Stroke risk profile assessed by both CHADS2 and CHA2DS2-VASc scores was higher in patients with OSA (1.2 ± 0.9 vs. 0.8 ± 0.6; p vs. 1.5 ± 1.1; p = 0.001) than without it. Differences in the stroke risk remained significant across different age strata, and the trend for point values in CHADS2 and CHA2DS2-VASc scores rose along with OSA severity according to the apnea-hypopnea index (AHI; p for trend stroke prediction models.

Developing biogeochemical tracers of apatite weathering by ectomycorrhizal fungi

Science.gov (United States)

Vadeboncoeur, M. A.; Bryce, J. G.; Hobbie, E. A.; Meana-Prado, M. F.; Blichert-Toft, J.

2012-12-01

Chronic acid deposition has depleted calcium (Ca) from many New England forest soils, and intensive harvesting may reduce phosphorus (P) available to future rotations. Thin glacial till soils contain trace amounts of apatite, a primary calcium phosphate mineral, which may be an important long-term source of both P and Ca to ecosystems. The extent to which ECM fungi enhance the weathering rate of primary minerals in soil which contain growth-limiting nutrients remains poorly quantified, in part due to biogeochemical tracers which are subsequently masked by within-plant fractionation. Rare earth elements (REEs) and Pb isotope ratios show some potential for revealing differences in soil apatite weathering rates across forest stands and silvicultural treatments. To test the utility of these tracers, we grew birch seedlings semi-hydroponically under controlled P-limited conditions, supplemented with mesh bags containing granite chips. Our experimental design included nonmycorrhizal (NM) as well as ectomycorrhizal cultures (Cortinarius or Leccinum). Resulting mycorrhizal roots and leachates of granite chips were analyzed for these tracers. REE concentrations in roots were greatly elevated in treatments with granite relative to those without granite, demonstrating uptake of apatite weathering products. Roots with different mycorrhizal fungi accumulated similar concentrations of REEs and were generally elevated compared to the NM cultures. Ammonium chloride leaches of granite chips grown in contact with mycorrhizal hyphae show elevated REE concentrations and significantly radiogenic Pb isotope signatures relative to bulk rock, also supporting enhanced apatite dissolution. Our results in culture are consistent with data from field-collected sporocarps from hardwood stands in the Bartlett Experimental Forest in New Hampshire, in which Cortinarius sporocarp Pb isotope ratios were more radiogenic than those of other ectomycorrhizal sporocarps. Taken together, the experimental

Investigation of composition and structure of spongy and hard bone tissue using FTIR spectroscopy, XRD and SEM

Science.gov (United States)

Al-Akhras, M.-Ali H.; Hasan Qaseer, M. K.; Albiss, B. A.; Alebrhim, M. Anwar; Gezawa, Umar S.

2018-02-01

Valuable structural and chemical features can be obtained for spongy and hard bone by infrared spectroscopy and X-ray diffraction. A better understanding of chemical and structural differences between spongy and hard bone is a very important contributor to bone quality. Our data according to IR data showed that the collagen cross-links occurred to be higher in spongy bone, and crystallinity was lower in spongy bone. Deconvolution of the infrared band near 870 cm-1 reveals evidence for A2-type carbonate substitution on hydroxyapatite of spongy bone in addition to the A and B type carbonate substitution that are also found in hard bone. IR and XRD data confirmed the results of each other since full width at half maximum of 002-apatite pattern of XRD showed that the crystallinity was lower in spongy bone. The microstructure was examined by using scanning electron microscope and the result showed that the lattice of thin threads in spongy bone and is less dense than hard bone.

Nanostructured Mesoporous Silicas for Bone Tissue Regeneration

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Isabel Izquierdo-Barba

2008-01-01

Full Text Available The research on the development of new biomaterials that promote bone tissue regeneration is receiving great interest by the biomedical scientific community. Recent advances in nanotechnology have allowed the design of materials with nanostructure similar to that of natural bone. These materials can promote new bone formation by inducing the formation of nanocrystalline apatites analogous to the mineral phase of natural bone onto their surfaces, i.e. they are bioactive. They also stimulate osteoblast proliferation and differentiation and, therefore, accelerate the healing processes. Silica-based ordered mesoporous materials are excellent candidates to be used as third generation bioceramics that enable the adsorption and local control release of biological active agents that promote bone regeneration. This local delivery capability together with the bioactive behavior of mesoporous silicas opens up promising expectations in the bioclinical field. In this review, the last advances in nanochemistry aimed at designing and tailoring the chemical and textural properties of mesoporous silicas for biomedical applications are described. The recent developed strategies to synthesize bioactive glasses with ordered mesopore arrangements are also summarized. Finally, a deep discussion about the influence of the textural parameters and organic modification of mesoporous silicas on molecules adsorption and controlled release is performed.

A likely planet-induced gap in the disc around T Cha

Science.gov (United States)

Hendler, Nathanial P.; Pinilla, Paola; Pascucci, Ilaria; Pohl, Adriana; Mulders, Gijs; Henning, Thomas; Dong, Ruobing; Clarke, Cathie; Owen, James; Hollenbach, David

2018-03-01

We present high-resolution (0.11 × 0.06 arcsec2) 3 mm ALMA observations of the highly inclined transition disc around the star T Cha. Our continuum image reveals multiple dust structures: an inner disc, a spatially resolved dust gap, and an outer ring. When fitting sky-brightness models to the real component of the 3 mm visibilities, we infer that the inner emission is compact (≤1 au in radius), the gap width is between 18 and 28 au, and the emission from the outer ring peaks at ˜36 au. We compare our ALMA image with previously published 1.6 μm VLT/SPHERE imagery. This comparison reveals that the location of the outer ring is wavelength dependent. More specifically, the peak emission of the 3 mm ring is at a larger radial distance than that of the 1.6 μm ring, suggesting that millimeter-sized grains in the outer disc are located farther away from the central star than micron-sized grains. We discuss different scenarios to explain our findings, including dead zones, star-driven photoevaporation, and planet-disc interactions. We find that the most likely origin of the dust gap is from an embedded planet, and estimate - for a single planet scenario - that T Cha's gap is carved by a 1.2MJup planet.

Fission track ages and uranium concentration of apatites of different rocks of South India

International Nuclear Information System (INIS)

Nand Lal; Nagpaul, K.K.; Nagpal, M.K.

1975-01-01

The uranium concentration and ages of apatite grains of various rocks of South India have been measured by fission track technique. The ages range from 100 m.y. to 730 m.y. whereas uranium concentrations vary from 0.5 to 23.8 atom/million atoms of the apatite mineral. The ages agree well with the Deccan volcanic and Ocean Cycle activities. (author)

Preparation of rare earth fluorides from apatite concentrate

International Nuclear Information System (INIS)

Mulyarchuk, I.F.; Voloshchenko, M.V.; Zen'kovich, E.G.; Sumenkova, V.V.; AN Ukrainskoj SSR, Kiev. Inst. Problem Lit'ya)

1980-01-01

The processes of preparation of the rare earths element sum from apatite concentrate of the Khibins, connected with preliminary extraction of rare earth phosphates from nitric acid extract using solvent extraction or direct precipitation from the extract by solution of potassium and ammonium fluorides. The sequence of the processes of the first variant is the following: solvent extraction of rare earths by tributylphosphate from clarified nitric acid extract of apatite with subsequent reextraction of rare earths with water and precipitation of rare earth phosphates from aqueous solution during neutralization by ammonia. In case of fluoride preparation from rare earth phosphate the main attention is paid to precipitation and filtration of fluorides. Technological scheme and cost price of industry for the production of 1800 t of rare earth trifluorides a year are calculated. When taking account of TBP losses according to its solubility the industry cost price is 1O times lower the modern cost of rare earth fluorides

Apatite-brannerite-pitchblende association in hydrothermal quartz veins

International Nuclear Information System (INIS)

Brodin, B.V.; Mel'nikova, A.M.; Osipov, B.S.; Pavlov, E.G.

1976-01-01

A study into the vein quartz mineralization confined to the tectonic zones of crush and silicification in sedimentary-igneous rocks of the lower Paleozoic has been made. The physicochemical characteristics of minerals were studied by way of optical and electron microscopy, chemical, laser-microspectral and X-ray structural analyses, microprobing and alpha-microradiography. 3 mineral associations have been discriminated, representative of the sequence of hydrothermal mineralization. An unusual parogenesis of pitchblende and brannerite with apatite, xenotime and more recent goethite has been revealed. The results are indicative of a medium-low-temperature hydrothermal process occurring at the final stages of formation of uraniferrous quartz veins. By composition and mineralization sequence, the latters are close to low- and medium-temperature uranium-quartz-chlorite-hydromica formations with apatite, coffinite, brannerite and pitchblende. The weak initial metamictization of goethite in veins 80 to 100 million years old is due to the radioactive effect of the submicroscopic radioactive mineral impurity on the crystalline lattice

Nanoceramics on osteoblast proliferation and differentiation in bone tissue engineering.

Science.gov (United States)

Sethu, Sai Nievethitha; Namashivayam, Subhapradha; Devendran, Saravanan; Nagarajan, Selvamurugan; Tsai, Wei-Bor; Narashiman, Srinivasan; Ramachandran, Murugesan; Ambigapathi, Moorthi

2017-05-01

Bone, a highly dynamic connective tissue, consist of a bioorganic phase comprising osteogenic cells and proteins which lies over an inorganic phase predominantly made of CaPO 4 (biological apatite). Injury to bone can be due to mechanical, metabolic or inflammatory agents also owing pathological conditions like fractures, osteomyelitis, osteolysis or cysts may arise in enameloid, chondroid, cementum, or chondroid bone which forms the intermediate tissues of the body. Bone tissue engineering (BTE) applies bioactive scaffolds, host cells and osteogenic signals for restoring damaged or diseased tissues. Various bioceramics used in BTE can be bioactive (like glass ceramics and hydroxyapatite bioactive glass), bioresorbable (like tricalcium phosphates) or bioinert (like zirconia and alumina). Limiting the size of these materials to nano-scale has resulted in a higher surface area to volume ratio thereby improving multi-functionality, solubility, surface catalytic activity, high heat and electrical conductivity. Nanoceramics have been found to induce osteoconduction, osteointegration, osteogenesis and osteoinduction. The present review aims at summarizing the interactions of nanoceramics and osteoblast/stem cells for promoting the proliferation and differentiation of the osteoblast cells by nanoceramics as superior bone substitutes in bone tissue engineering applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Prestroke CHA2DS2-VASc Score and Severity of Acute Stroke in Patients with Atrial Fibrillation: findings from RAF Study

OpenAIRE

Acciarresi, Monica; Paciaroni, Maurizio; Agnelli, Giancarlo; Falocci, Nicola; Caso, Valeria; Becattini, Cecilia; Marcheselli, Simona; Rueckert, Christina; Pezzini, Alessandro; Morotti, Andrea; Costa, Paolo; Padovani, Alessandro; Csiba, László; Szabó, Lilla; Sohn, Sung-Il

2017-01-01

Background and Purpose:\\ud \\ud The aim of this study was to investigate for a possible association between both prestroke CHA2DS2-VASc score and the severity of stroke at presentation, as well as disability and mortality at 90 days, in patients with acute stroke and atrial fibrillation (AF).\\ud Methods:\\ud \\ud This prospective study enrolled consecutive patients with acute ischemic stroke, AF, and assessment of prestroke CHA2DS2-VASc score. Severity of stroke was assessed on admission using t...

Electron Microscopy and Analytical X-ray Characterization of Compositional and Nanoscale Structural Changes in Fossil Bone

Science.gov (United States)

Boatman, Elizabeth Marie

The nanoscale structure of compact bone contains several features that are direct indicators of bulk tissue mechanical properties. Fossil bone tissues represent unique opportunities to understand the compact bone structure/property relationships from a deep time perspective, offering a possible array of new insights into bone diseases, biomimicry of composite materials, and basic knowledge of bioapatite composition and nanoscale bone structure. To date, most work with fossil bone has employed microscale techniques and has counter-indicated the survival of bioapatite and other nanoscale structural features. The obvious disconnect between the use of microscale techniques and the discernment of nanoscale structure has prompted this work. The goal of this study was to characterize the nanoscale constituents of fossil compact bone by applying a suite of diffraction, microscopy, and spectrometry techniques, representing the highest levels of spatial and energy resolution available today, and capable of complementary structural and compositional characterization from the micro- to the nanoscale. Fossil dinosaur and crocodile long bone specimens, as well as modern ratite and crocodile femurs, were acquired from the UC Museum of Paleontology. Preserved physiological features of significance were documented with scanning electron microscopy back-scattered imaging. Electron microprobe wavelength-dispersive X-ray spectroscopy (WDS) revealed fossil bone compositions enriched in fluorine with a complementary loss of oxygen. X-ray diffraction analyses demonstrated that all specimens were composed of apatite. Transmission electron microscopy (TEM) imaging revealed preserved nanocrystallinity in the fossil bones and electron diffraction studies further identified these nanocrystallites as apatite. Tomographic analyses of nanoscale elements imaged by TEM and small angle X-ray scattering were performed, with the results of each analysis further indicating that nanoscale structure is

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

International Nuclear Information System (INIS)

Son, Kyung Mi; Park, Hee Chul; Kim, Na Ryoung; Yang, Hyeong-Cheol; Lee, In-Seop

2010-01-01

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, 20α-hydroxycholesterol (20α-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 20α-HC was significantly higher with ascorbic acid than alone, suggesting a need for ascorbic acid as a co-factor. When 20α-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 20α-HC was loaded by volatilization of EtOH from the apatite coat after dipping discs in 20α-HC-dissolved EtOH. Interestingly, ascorbic acid was not needed for this increase in ALP activity, suggesting a synergistic effect of 20α-HC and apatite. The concentration of calcium ions, a major component of apatite, affected the osteogenic effect of 20α-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 20α-HC and apatite.

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

Energy Technology Data Exchange (ETDEWEB)

Baran, E J; Botto, I L; Aymonino, P J [La Plata Univ. Nacional (Argentina). Facultad de Ciencias Exactas

1976-06-01

The infrared and Raman spectra of Pb/sub 3/(VO/sub 4/)/sub 2/ are recorded and discussed with the aid of the 'site symmetry' rules. The i.r. spectra of the compounds Pb/sub 5/(VO/sub 4/)/sub 3/X (X=F, Cl, Br), Pb/sub 5/(VO/sub 4/)/sub 2/GeO/sub 4/, Pb/sub 5/(VO/sub 4/)/sub 2/SiO/sub 4/ (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.

Nucleation and growth of apatite on NaOH-treated PEEK, HDPE and UHMWPE for artificial cornea materials.

Science.gov (United States)

Pino, M; Stingelin, N; Tanner, K E

2008-11-01

The skirt of an artificial cornea must integrate the implant to the host sclera, a major failure of present devices. Thus, it is highly desirable to encourage the metabolic activity of the cornea by using more bioactive, flexible skirt materials. Here we describe attempts to increase the bioactivity of polyether ether ketone (PEEK), high-density polyethylene (HDPE) and ultra-high molecular weight polyethylene (UHMWPE) films. The effectiveness of different strength NaOH pre-treatments to initiate apatite deposition on PEEK, HDPE and UHMWPE is investigated. We find that exposure of PEEK, HDPE and UHMWPE films to NaOH solutions induces the formation of potential nuclei for apatite (calcium phosphate), from which the growth of an apatite coating is stimulated when subsequently immersing the polymer films in 1.5 strength Simulated Body Fluid (SBF). As immersion time in SBF increases, further nucleation and growth produces a thicker and more compact apatite coating that can be expected to be highly bioactive. Interestingly, the apatite growth is found to also be dependent on both the concentration of NaOH solution and the structure of the polymer surface.

Regenerative potential and anti-bacterial activity of tetracycline loaded apatitic nanocarriers for the treatment of periodontitis

International Nuclear Information System (INIS)

Madhumathi, K; Sampath Kumar, T S

2014-01-01

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)

Antinociceptive activity of fruits extracts and "arrope" of Geoffroea decorticans (chañar).

Science.gov (United States)

Reynoso, M A; Vera, N; Aristimuño, M E; Daud, A; Sánchez Riera, A

2013-01-09

Geoffroea decorticans (chañar) fruits and their derivate product (arrope) have been traditionally used as food and a folk medicine for the treatment of a wide variety of diseases including bronchopulmonary disorders and to relieve dolorous process. In order to evaluate the pharmacology action of this plant, studies were performed of antinociceptive and antioxidant activities. The aqueous and ethanolic extracts and arrope of chañar were evaluated in various established pain models, including chemical nociception induced by subplantar formalin and intraperitoneal acetic acid and thermal nociception method, such as tail immersion test in rats. To examine the possible connection of the opioid receptor to the antinociceptive activity of extracts and arrope it was performed a combination test with naloxone, a non-selective opioid receptor antagonist. The aqueous extract and arrope (1000 mg/kg) caused an inhibition of the pain in formalin test in the first phase, similar to morphine and decrease in the second phase. In a combination test using naloxone, diminished analgesic activity of aqueous extract and arrope were observed, indicating that antinociceptive activity is connected with the opioid receptor. The aqueous extract and arrope, caused an inhibition of the writhing response induced by acetic acid. Central involvement in analgesic profile was confirmed by the tail immersion test, in which the aqueous extract and arrope showed a significant analgesic activity by increasing latency time. The aqueous extract showed higher antioxidant activity than the arrope, it may be due to the cooking process. This study has shown that the aqueous extract and arrope of Geoffroea decorticans (chañar) fruits, does possess significant antinociceptive effects. It is further concluded that aqueous extract with maximum inhibition of free radical is the most potent extract amount tested extracts. At the oral doses tested the aqueous extract and arrope were non-toxic. The present

Development of implant/interconnected porous hydroxyapatite complex as new concept graft material.

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Kazuya Doi

Full Text Available BACKGROUND: Dental implant has been successfully used to replace missing teeth. However, in some clinical situations, implant placement may be difficult because of a large bone defect. We designed novel complex biomaterial to simultaneously restore bone and place implant. This complex was incorporated implant into interconnected porous calcium hydroxyapatite (IP-CHA. We then tested this Implant/IP-CHA complex and evaluated its effect on subsequent bone regeneration and implant stability in vivo. METHODOLOGY/PRINCIPAL FINDINGS: A cylinder-type IP-CHA was used in this study. After forming inside of the cylinder, an implant was placed inside to fabricate the Implant/IP-CHA complex. This complex was then placed into the prepared bone socket in the femur of four beagle-Labrador hybrid dogs. As a control, implants were placed directly into the femur without any bone substrate. Bone sockets were allowed to heal for 2, 3 and 6 months and implant stability quotients (ISQ were measured. Finally, tissue blocks containing the Implant/IP-CHA complexes were harvested. Specimens were processed for histology and stained with toluidine blue and bone implant contact (BIC was measured. The ISQs of complex groups was 77.8±2.9 in the 6-month, 72.0±5.7 in the 3-month and 47.4±11.0 in the 2-month. There was no significant difference between the 3- or 6-month complex groups and implant control groups. In the 2-month group, connective tissue, including capillary angiogenesis, was predominant around the implants, although newly formed bone could also be observed. While, in the 3 and 6-month groups, newly formed bone could be seen in contact to most of the implant surface. The BICs of complex groups was 2.18±3.77 in the 2-month, 44.03±29.58 in the 3-month, and 51.23±8.25 in the 6-month. Significant difference was detected between the 2 and 6-month. CONCLUSIONS/SIGNIFICANCE: Within the results of this study, the IP-CHA/implant complex might be able to achieve both

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

International Nuclear Information System (INIS)

Ravenhurst, C.E.; Roden-Tice, M.K.; Miller, D.S.

2003-01-01

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 HNO 3 at 21 o C 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 HNO 3 ) 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)

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

International Nuclear Information System (INIS)

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

2011-01-01

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 3 PO 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.

Removal of cadmium, copper, nickel, cobalt and mercury from water by Apatite II{sup TM}: Column experiments

Energy Technology Data Exchange (ETDEWEB)

Oliva, Josep [Department of Mining Engineering and Natural Resou-rces, Universitat Politecnica de Catalunya, Bases de Manresa 61-73, 08242 Manresa, Catalonia (Spain); De Pablo, Joan [Department of Chemical Engineering, Universitat Politecnica de Catalunya, Diagonal 647, 08028 Barcelona, Catalonia (Spain); Cortina, Jose-Luis, E-mail: jose.luis.cortina@upc.edu [Department of Chemical Engineering, Universitat Politecnica de Catalunya, Diagonal 647, 08028 Barcelona, Catalonia (Spain); Water Technology Center, CETaqua, Paseo de los Tilos 3, 08034 Barcelona, Catalonia (Spain); Cama, Jordi; Ayora, Carlos [Institute of Environmental Assessment and Water Research, IDAEA, CSIC, Jordi Girona 18, 08034 Barcelona, Catalonia (Spain)

2011-10-30

Highlights: {yields} The efficiency of Apatite II{sup TM} 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. {yields} 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 II{sup TM}. {yields} Compared with other reactive materials such as limestone and caustic magnesia that exhibit a reduction of porosity Apatite II{sup TM} showed stable hydraulic performance. {yields} The extrapolation of the column durabilities to a 1-m-thick passive treatment suggests that the Apatite II{sup TM} filling can be active between 5 and 10 years for an inflow pH exceeding 5. - Abstract: Apatite II{sup TM}, a biogenic hydroxyapatite, was evaluated as a reactive material for heavy metal (Cd, Cu, Co, Ni and Hg) removal in passive treatments. Apatite II{sup TM} 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. Cd{sub 5}(PO{sub 4}){sub 3}OH(s), Cu{sub 2}(PO{sub 4})OH(s), Ni{sub 3}(PO{sub 4}){sub 2}(s), Co{sub 3}(PO{sub 4}){sub 2}8H{sub 2}O(s) and Hg{sub 3}(PO{sub 4}){sub 2}(s) are proposed as the possible mineral phases responsible for the removal

A temporal record of pre-eruptive magmatic volatile contents at Campi Flegrei: Insights from texturally-constrained apatite analyses

Science.gov (United States)

Stock, Michael J.; Isaia, Roberto; Humphreys, Madeleine C. S.; Smith, Victoria C.; Pyle, David M.

2016-04-01

Apatite is capable of incorporating all major magmatic volatile species (H2O, CO2, S, Cl and F) into its crystal structure. Analysis of apatite volatile contents can be related to parental magma compositions through the application of pressure and temperature-dependent exchange reactions (Piccoli and Candela, 1994). Once included within phenocrysts, apatite inclusions are isolated from the melt and preserve a temporal record of magmatic volatile contents in the build-up to eruption. In this work, we measured the volatile compositions of apatite inclusions, apatite microphenocrysts and pyroxene-hosted melt inclusions from the Astroni 1 eruption of Campi Flegrei, Italy (Stock et al. 2016). These data are coupled with magmatic differentiation models (Gualda et al., 2012), experimental volatile solubility data (Webster et al., 2014) and thermodynamic models of apatite compositional variations (Piccoli and Candela, 1994) to decipher pre-eruptive magmatic processes. We find that apatite halogen/OH ratios decreased through magmatic differentiation, while melt inclusion F and Cl concentrations increased. Melt inclusion H2O contents are constant at ~2.5 wt%. These data are best explained by volatile-undersaturated differentiation over most of the crystallisation history of the Astroni 1 melt, with melt inclusion H2O contents reset at shallow levels during ascent. Given the high diffusivity of volatiles in apatite (Brenan, 1993), the preservation of volatile-undersaturated melt compositions in microphenocrysts suggests that saturation was only achieved 10 - 103 days before eruption. We suggest that late-stage transition into a volatile-saturated state caused an increase in magma chamber overpressure, which ultimately triggered the Astroni 1 eruption. This has major implications for monitoring of Campi Flegrei and other similar volcanic systems. Piccoli and Candela, 1994. Am. J. of Sc., 294, 92-135. Stock et al., 2016, Nat. Geosci. Gualda et al., 2012. J. Pet., 53, 875

Treatment of Common Cold Patients with the Shi-Cha Capsule: A Multicenter, Double-Blind, Randomized, Placebo-Controlled, Dose-Escalation Trial

Science.gov (United States)

Chang, Jing; Dong, Shou-Jin; She, Bin; Zhang, Rui-Ming; Meng, Mao-Bin; Xu, Yan-Ling; Wan, Li-Ling; Shi, Ke-Hua; Pan, Jun-Hun; Mao, Bing

2012-01-01

This study was designed to determine the therapeutic efficacy and safety of the Shi-cha capsule, a Chinese herbal formula, in the treatment of patients with wind-cold type common cold. In our multi-center, prospective, double-blind, randomized, placebo-controlled, dose-escalation trial, patients with wind-cold type common cold received 0.6 g of Shi-cha capsule plus 0.6 g placebo (group A), 1.2 g of Shi-cha capsule (group B), or 1.2 g placebo (group C), three times daily for 3 days and followed up to 10 days. The primary end point was all symptom duration. The secondary end points were main symptom duration, minor symptom duration, the changes in cumulative symptom score, main symptom score, and minor symptom score 4 days after the treatment, as well as adverse events. A total of 377 patients were recruited and 360 met the inclusive criteria; 120 patients constituted each treatment group. Compared with patients in group C, patients in groups A and B had significant improvement in the all symptom duration, main symptom duration, minor symptom duration, as well as change from baseline of cumulative symptom score, main symptom score, and minor symptom score at day 4. The symptom durations and scores showed slight superiority of group B over group A, although these differences were not statistically significant. There were no differences in adverse events. The Shi-cha capsule is efficacious and safe for the treatment of patients with wind-cold type common cold. Larger trials are required to fully assess the benefits and safety of this treatment for common cold. PMID:23346193

Use of the CHA2DS2VASc score to reduce utilisation of transoesophageal echocardiography prior to ablation for atrial fibrillation

Directory of Open Access Journals (Sweden)

Charlotte Atkinson

2017-10-01

Full Text Available Transoesophageal echocardiography (TOE is frequently performed prior to atrial fibrillation (AF ablation to exclude left atrial appendage (LAA thrombus. However, patients undergoing AF ablation are usually anticoagulated, thus making the presence of thrombus unlikely in most cases. This study aimed to determine whether the CHA2DS2VASc scoring system can be used to identify patients that do not require TOE prior to AF ablation. In this single-centre retrospective study, local institutional and primary care databases and electronic patient records were searched to identify patients that had undergone TOE prior to AF ablation. Patient demographics, CHA2DS2VASc score, TOE findings and anticoagulation status were collected for analysis. Over a 7-year period (2008–2014, 332 patients (age 57 ± 10 years; 74% male underwent TOE prior to proposed AF ablation. CHA2DS2VASc scores of 0, 1, 2 and >2 were found in 39, 34, 15 and 12% of patients, respectively. The prevalence of LAA thrombus was 0.6% (2 patients and these 2 patients had risk scores of 2 and 4. No patients with a score of 0 or 1 had LAA thrombus. Patients that are classed as low risk by the CHA2DS2VASc score do not require a pre-ablation TOE to screen for LAA thrombus provided they are adequately anticoagulated. This would lead to a significant reduction in health care expenditures by reducing unnecessary TOE requests and thereby improve patient experience.

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

International Nuclear Information System (INIS)

Pramana, S.S.; White, T.J.

2007-01-01

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 10 (GeO 4 ) 6 O 3 ', it has been shown that this compound is more correctly described as an La 10 (GeO 4 ) 5- (GeO 5 )O 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 4 tetrahedra to GeO 5 distorted trigonal bipyramids. This structural modification is consistent with known crystal chemistry and may occur generally in oxide apatites. (orig.)

Influence of Common Bean (Phaseolus vulgaris) Grown in Elevated CO2 on Apatite Dissolution

Science.gov (United States)

Olsen, A. A.; Morra, B.

2016-12-01

We ran a series of experiments to test the hypothesis that release of plant nutrients contained in apatite will be accelerated by the growth of Langstrath Stringless green bean in the presence of atmospheric CO2 meant to simulate possible future atmospheric conditions due a higher demand of nutrients and growth rate caused by elevated CO2. We hypothesize that elevated atmospheric CO2 will lead to both increased root growth and organic acid exudation. These two traits will lead to improved acquisition of P derived from apatite. Experiments were designed to investigate the effect of these changes on soil mineral weathering using plants grown under two conditions, ambient CO2 (400ppm) and elevated CO2 (1000ppm). Plants were grown in flow-through microcosms consisting of a mixture of quartz and apatite sands. Mini-greenhouses were utilized to control CO2 levels. Plant growth was sustained by a nutrient solution lacking in Ca and P. Calcium and P content of the leachate and plant tissue served as a proxy for apatite dissolution. Plants were harvested biweekly during the eight-week experiment and analyzed for Ca and P to calculate apatite dissolution kinetics. Preliminary results suggest that approximately four times more P and Ca are present in the leachate from experiments containing plants under both ambient and elevated CO2 levels than in abiotic experiments; however, the amounts of both P and Ca released in experiments conducted under both ambient and elevated CO2 levels are similar. Additionally, the amount of P in plant tissue grown under ambient and elevated CO2 conditions is similar. Plants grown in elevated CO2 had a greater root to shoot ratio. The planted microcosms were found to have a lower pH than abiotic controls most likely due to root respiration and exudation of organic acids.

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

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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

Radiation damage studies of mineral apatite, using fission tracks and thermoluminescence techniques

International Nuclear Information System (INIS)

Al-Khalifa, I.J.M.

1988-01-01

In a uranium (/thorium)-rich mineral sample which has not suffered a recent geological high-temperature excursion, the fossil fission track density (FFTD) will give a good indication of its natural radiation damage, provided that its U/Th ratio is known. From our studies of FFTD and thermoluminescence (TL) properties of several samples of apatite from different locations, and containing varying degrees of natural-radiation damage, an anti-correlation is observed between FFTD and TL sensitivity. It is also found that an anti-correlation exists between TL sensitivity and the amount of damage produced artificially by bombarding apatite crystals with different fluences of ∼30 MeV α-particles from a cyclotron. These results indicate that the presence of radiation damage in this mineral (viz., fluorapatite) can severely affect its TL sensitivity (i.e. TL output per unit test dose). The effect of crystal composition on the thermoluminescence and fission track annealing properties of mineral apatite is also reported. We have found that fission track annealing sensitivity and TL sensitivity are both significantly lower in samples of chlorapatite than in samples consisting predominantly of fluorapatite. (author)

Influence of agitation intensity on flotation rate of apatite particles

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Francisco Gregianin Testa

Full Text Available Abstract The agitation intensity has a directly influence on flotation performance, lifting the particles and promoting the contact of bubbles and particles. In this paper, the energy input by the agitation on apatite flotation was investigated. The influence of pulp agitation in the flotation rate of particles with different sizes and two dosage levels was evaluated by batch testing. The flotation tests were conducted in an oscillating grid flotation cell (OGC, developed to promote a near isotropic turbulence environment. The cell is able to control the intensity of agitation and measure the energy transferred to the pulp phase. A sample of pure apatite was crushed (P80=310µm, characterized and floated with sodium oleate as collector. Four levels of energy dissipation, from 0.1 to 2 kWm-3, and two levels of collector dosage are used during the tests. The flotation kinetics by particle size were determined in function of the energy transferred. The results show a strong influence of the agitation intensity on the apatite flotation rate with both low and high dosage. For fine particles, when increasing the energy input, the flotation rate increase too, and this fact can be attributed to elevation of bubble-particle collisions. The kinetic result for the coarse particles demonstrated a reduction of the flotation rate whenever the energy input for this particle size was increased, whereby the turbulence caused by the agitation promotes the detachment of bubble-particle.

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.

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.;

Characterization and potential application of pataua vegetable oil in apatite flotation

International Nuclear Information System (INIS)

Oliveira, P.S. de; Mansur, H.S.; Peres, A.E.C.

2016-01-01

The present research characterizes the Pataua palm (Oenocarpus bataua) oil regarding to its fatty acids profile and acidity index, and evaluates its use for apatite flotation. The Pataua oil evaluated is unsaturated e predominantly composed of cis-9-octadecenoic acid (oleic acid). The mineral sample characterization revealed a material composed by a fluoroapatite deficient in fluorine, a possibly result of isomorphic substitution, and with quartz and monazite inclusions. The analysis of the mineral after reagent conditioning, by Fourier Transform Infrared Spectroscopy (FTIR), pointed to the presence of characteristic bands of carbon chains and carboxylate group, suggesting the collector adsorption through the mechanisms of chemisorption and insoluble calcium salts precipitation. Thus, it is proposed the Pataua oil potential use in flotation systems aiming apatite recovery. (author)

Apatite fission track evidence on the uplifting of eastern Kunlun mountains

International Nuclear Information System (INIS)

Yuang Wanming; Dong Jinquan; Tang Yunhui; Wang Shicheng

2004-01-01

A series of samples were collected from about south-north section through Buqingshan and Dulan, eastern Kunlun mountains, China. The 41 apatite fission track ages (FTA) of these samples lie between 25.2 and 130.4 Ma, all of the apatite fission track ages are significantly younger than the host rocks. There are similar evolution trends for Middle-Kunlun zone and North-Kunlun zone, i.e. the FTA becomes less with slow increase of elevations and their uplifting rates are about 2.22 m/Ma. Differently, the FTA in South-Kunlun zone positively correlates to elevation, decreasing 11 m/Ma. It may be shown that South-Kunlun fault play a different and/or more important role on incontinent evolution than Middle-Kunlun fault. (author)

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.

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

International Nuclear Information System (INIS)

Szubert, M.; Adamska, K.; Szybowicz, M.; Jesionowski, T.; Buchwald, T.; Voelkel, A.

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

Calcitonin, phosphate, and the osteocyte--osteoblast bone cell unit

Energy Technology Data Exchange (ETDEWEB)

Talmage, R.V.; Matthews, J.L.; Martin, J.H.; Kennedy, J.W. III; Davis, W.L.; Roycroft, J.H. Jr.

1974-01-01

In this report we have attempted to correlate the morphological and chemical changes that occur in the long bone (tibia) of rats with the hypocalcemia that is produced following calcitonin injection or release from its gland of origin. By varying the supply of phosphate available to the rat, it has been possible to demonstrate that changes produced by CT both in bone and in plasma calcium concentrations were dependent upon an adequate supply of this ion. It is, therefore, postulated that the hypocalcemia produced by calcitonin is secondary to the formation of a calcium phosphate complex in and around osteocytes and lining cells. It is suggested that this complex, which is normally prevented from transforming to apatite crystal by the presence of an inhibitor, reduces the availability of calcium for rapid transport to the ECF. The reduction in calcium flux from bone to ECF results in a rapid and transient hypocalcemia. Regardless of the status of this postulate, we have at least demonstrated that the osteocyte-osteoblast unit of compact bone reacts rapidly to calcitonin in a process requiring phosphate in a sequence of events which can be closely correlated to the hypocalcemic action of the hormone.

AHP 24: A Multi-ethnic Village in Northeast Tibet - History, Ritual, and Daily Life in Chu cha

Directory of Open Access Journals (Sweden)

Stobs stag lha སྟོབས་སྟག་ལྷ།

2013-09-01

Full Text Available Multi-ethnic Chu cha Village in Mchod rten thang Township, Dpa' ris Tibetan Autonomous County, Gansu Province, China is described in terms of location; population; clothing; language; religion; history; and personal, family, and community rituals. Photographs provide additional information.

Formation of apatite layers on modified canasite glass-ceramics in simulated body fluid.

Science.gov (United States)

Miller, C A; Kokubo, T; Reaney, I M; Hatton, P V; James, P F

2002-03-05

Canasite glass-ceramics were modified by either increasing the concentration of calcium in the glass, or by the addition of P2O5. Samples of these novel materials were placed in simulated body fluid (SBF), along with a control material (commercial canasite), for periods ranging from 12 h to 28 days. After immersion, surface analysis was performed using thin film X-ray diffraction, Fourier transform infrared reflection spectroscopy, and scanning electron microscopy equipped with energy dispersive X-ray detectors. The concentrations of sodium, potassium, calcium, silicon, and phosphorus in the SBF solution were measured using inductively coupled plasma emission spectroscopy. No apatite was detected on the surface of commercial canasite, even after 28 days of immersion in SBF. A crystalline apatite layer was formed on the surface of a P2O5-containing canasite after 5 days, and after 3 days for calcium-enriched canasite. Ion release data suggested that the mechanism for apatite deposition was different for P2O5 and non-P2O5-containing glass-ceramics. Copyright 2001 John Wiley & Sons, Inc.

Impact of CHA2DS2VASc Score on Candidacy for Anticoagulation in Patients With Atrial Fibrillation: A Multi-payer Analysis.

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Patel, Aarti A; Nelson, Winnie W; Schein, Jeff

2016-10-01

The purpose of this study is to report on the effect of using CHA 2 DS 2 VASc (congestive heart failure, hypertension, age ≥75 years [doubled], type 1 or type 2 diabetes mellitus, stroke or transient ischemic attack or thromboembolism [doubled], vascular disease [prior myocardial infarction, peripheral artery disease, or aortic plaque], age 65-75 years, sex category [female]) rather than CHADS 2 (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, and prior stroke) to determine candidacy for anticoagulant prophylaxis in insured patients with atrial fibrillation (AF). Six administrative claims databases that included medical and pharmacy claims for patients aged ≥18 years with a new or existing diagnosis of AF and patient outcomes assessed for 1 year after diagnosis were analyzed. Retrospective health plan data analyses were performed using a software tool (Anticoagulant Quality Improvement Analyzer). Study measures included stroke risk (identified by CHADS 2 and CHA 2 DS 2 VASc scores), bleeding risk (identified by the Anticoagulation and Risk Factors in Atrial Fibrillation score), and anticoagulant use. A total of 115,906 patients with AF (range of mean ages among the 6 databases, 56-79 years) met the inclusion criteria. All ranges reported represent the minimum and maximum values among the 6 databases. Using the CHA 2 DS 2 VASc compared with the CHADS 2 index to assess stroke risk resulted in a 23% to 32% increase in patients considered potential candidates for anticoagulant prophylaxis. This translated to a 38% to 114% increase in the number of ostensibly undertreated patients. Among patients with high stroke and low bleeding risk, 18% to 28% more patients were considered potential candidates for anticoagulation treatment using CHA 2 DS 2 VASc compared with CHADS 2 , or a 57% to 151% increase in the number of undertreated patients. Use of the CHA 2 DS 2 VASc score to determine the risk of stroke increased the number of AF patients for

On the reproducibility of apatite fission-track plateau-age dating

International Nuclear Information System (INIS)

Poupeau, G.; Baitelli, R.; Berbert, M.; Fonseca, A.

1985-01-01

Duplicate measurements as well as published data show that plateau-age measurements on apatites have a reproducibility - when made in optical microscopy - generally better than +- 5%, which may be accounted for by statistical errors on track density measurement. (Author) [pt

The ultrastructure of bone and its relevance to mechanical properties

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Schwarcz, Henry P.; Abueidda, Diab; Jasiuk, Iwona

2017-09-01

Bone is a biologically generated composite material comprised of two major structural components: crystals of apatite and collagen fibrils. Computational analysis of the mechanical properties of bone must make assumptions about the geometric and topological relationships between these components. Recent transmission electron microscope (TEM) studies of samples of bone prepared using ion milling methods have revealed important previously unrecognized features in the ultrastructure of bone. These studies show that most of the mineral in bone lies outside the fibrils and is organized into elongated plates 5 nanometers (nm) thick, 80 nm wide and hundreds of nm long. These so-called mineral lamellae (MLs) are mosaics of single 5 nm-thick, 20 - 50 nm wide crystals bonded at their edges. MLs occur either stacked around the 50 nm-diameter collagen fibrils, or in parallel stacks of 5 or more MLs situated between fibrils. About 20% of mineral is in gap zones within the fibrils. MLs are apparently glued together into mechanically coherent stacks which break across the stack rather than delaminating. ML stacks should behave as cohesive units during bone deformation. Finite element computations of mechanical properties of bone show that the model including such features generates greater stiffness and strength than are obtained using conventional models in which most of the mineral, in the form of isolated crystals, is situated inside collagen fibrils.

Syntheses and characterizations of rare earth doped phospho-silicated apatites: application to nuclear waste confinement

International Nuclear Information System (INIS)

Boyer, Laurent

1998-01-01

Apatite matrices have been developed for the conditioning of actinides from spent fuels of PWR reactors. Silicated apatites (britholites) containing actinides and lanthanides have been discovered in the natural environment. Synthetic analogues of these britholites can be obtained by solid-solid reaction at high temperature. The compounds of the solid solution of fluorinated britholites are synthesized by the double substitution of (Ca 2+ , PO 4 3- ) by (Ln 3+ , SiO 4 4- ). Trivalent lanthanides are chemical analogues of trivalent actinides. The synthesis was performed with La, Nd and Eu. This study allows to demonstrate that the chemical immobilization comes from the fixation of rare earths at the atomic scale, thanks to their participation to the mineral structure. In part 1, the criteria for the formulation of a matrix for the conditioning of separate radionuclides are given. The structure and the different methods of apatite preparation are shown. Part 2 treats of the study of the solid solution, of the elaboration of the Ca 9 Nd 1 (SiO 4 ) 5 F 2 ceramic and of its physico chemical characterization. The last part deals with the localization of rare earths in the apatite structure, determined by europium luminescence and X-ray diffraction on monocrystal. (J.S.) [fr

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

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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. Copyright © 2013 Elsevier B.V. All rights reserved.

Implanted hydroxyapatite ossification kinetics study and interface bone-implant analysis by P.I.X.E. nuclear method

International Nuclear Information System (INIS)

Irigaray, J.L.; Oudadesse, H.; Braye, F.; Jallot, E.

1994-06-01

The hydroxy apatite (Hap) formula Ca-5(P O-4)--3 OH ceramics, may be doped when it is produced by elements (Ca, Zn...) which may influence the bone cells. We must determine the doping effects on the mechanical properties. The laboratory possesses a compression/traction bench, which measures the applied force on the sample according to the sensor engine moving. 27 refs., 39 figs., 9 tabs

Bone Repair on Fractures Treated with Osteosynthesis, ir Laser, Bone Graft and Guided Bone Regeneration: Histomorfometric Study

Science.gov (United States)

dos Santos Aciole, Jouber Mateus; dos Santos Aciole, Gilberth Tadeu; Soares, Luiz Guilherme Pinheiro; Barbosa, Artur Felipe Santos; Santos, Jean Nunes; Pinheiro, Antonio Luiz Barbosa

2011-08-01

The aim of this study was to evaluate, through the analysis of histomorfometric, the repair of complete tibial fracture in rabbits fixed with osteosynthesis, treated or not with infrared laser light (λ780 nm, 50 mW, CW) associated or not to the use of hydroxyapatite and guided bone regeneration (GBR). Surgical fractures were created, under general anesthesia (Ketamina 0,4 ml/Kg IP and Xilazina 0,2 ml/Kg IP), on the dorsum of 15 Oryctolagus rabbits that were divided into 5 groups and maintained on individual cages, at day/night cycle, fed with solid laboratory pelted diet and had water ad libidum. On groups II, III, IV and V the fracture was fixed with wire osteosynthesis. Animals of groups III and V were grafted with hydroxyapatite and GBR technique used. Animals of groups IV and V were irradiated at every other day during two weeks (16 J/cm2, 4×4 J/cm2). Observation time was that of 30 days. After animal death (overdose of general anesthetics) the specimes were routinely processed to wax and underwent histological analysis by light microscopy. The histomorfometric analysis showed an increased bone neoformation, increased collagen deposition, less reabsorption and inflammation when laser was associated to the HATCP. It is concluded that IR laser light was able to accelerate fracture healing and the association with HATCP and GBR resulted on increased deposition of CHA.

Using calcium silicate to regulate the physicochemical and biological properties when using β-tricalcium phosphate as bone cement

Energy Technology Data Exchange (ETDEWEB)

Kao, Chia-Tze; Huang, Tsui-Hsien [School of Dentistry, Chung Shan Medical University, Taichung, Taiwan (China); Department of Dentistry, Chung Shan Medical University Hospital, Taichung, Taiwan (China); Chen, Yi-Jyun [School of Dentistry, Chung Shan Medical University, Taichung, Taiwan (China); Department of Dentistry, Chung Shan Medical University Hospital, Taichung, Taiwan (China); Dental Department, Taichung Hospital, Ministry of Health and Welfare, Taichung City, Taiwan (China); Hung, Chi-Jr [School of Dentistry, Chung Shan Medical University, Taichung, Taiwan (China); Department of Dentistry, Chung Shan Medical University Hospital, Taichung, Taiwan (China); Lin, Chi-Chang, E-mail: chichang31@gmail.com [Department of Chemical and Materials Engineering, Tunghai University, Taichung, Taiwan (China); Shie, Ming-You, E-mail: eviltacasi@gmail.com [Department of Chemical and Materials Engineering, Tunghai University, Taichung, Taiwan (China)

2014-10-01

β-Tricalcium phosphate (β-TCP) is an osteoconductive material. For this research we have combined it with a low degradation calcium silicate (CS) to enhance its bioactive and osteostimulative properties. To check its effectiveness, a series of β-TCP/CS composites with different ratios were prepared to make new bioactive and biodegradable biocomposites for bone repair. Regarding the formation of bone-like apatite, the diametral tensile strength as well as the ion release and weight loss of composites were compared both before and after immersions in simulated body fluid (SBF). In addition, we also examined the behavior of human dental pulp cells (hDPCs) cultured on β-TCP/CS composites. The results show that the apatite deposition ability of the β-TCP/CS composites improves as the CS content is increased. For composites with more than a 60% CS content, the samples become completely covered by a dense bone-like apatite layer. At the end of the immersion period, weight losses of 24%, 32%, 34%, 38%, 41%, and 45% were observed for the composites containing 0%, 20%, 40%, 80%, 80% and 100% β-TCP cements, respectively. In addition, the antibacterial activity of CS/β-TCP composite improves as the CS-content is increased. In vitro cell experiments show that the CS-rich composites promote human dental pulp cell (hDPC) proliferation and differentiation. However, when the CS quantity in the composite is less than 60%, the quantity of cells and osteogenesis protein of hDPCs is stimulated by Si released from the β-TCP/CS composites. The degradation of β-TCP and the osteogenesis of CS give strong reason to believe that these calcium-based composite cements will prove to be effective bone repair materials. - Highlights: • CS improved the physicochemical properties and osteogenic activity of β-TCP. • Higher CS in the composite, the shorter setting time and the higher DTS was found. • With a CS more than 40%, the osteogenesis and angiogenesis proteins were promoted by

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

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

International Nuclear Information System (INIS)

Perrone, Jane

1999-01-01

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 10 (PO 4 ) 5 (CO 3 )(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 AmPO 4 ,xH 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 4 m 3 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)

Visualization of structural organization of ventral membranes of sheared-open resorbing osteoclasts attached to apatite pellets.

Science.gov (United States)

Akisaka, Toshitaka; Yoshida, Atsushi

2015-05-01

Osteoclasts are highly polarized cells from both morphological and functional points of view. Using quick-freeze, rotary-replication methods combined with cell-shearing, we clarified the variability of cytoplasmic surface of the polarized membranes of osteoclasts seeded on apatite. As to the organization of actin filaments and clathrin sheets, we confirmed almost the same ventral membrane specializations of osteoclasts on apatite as seen on glass plates. The organized actin filaments and membrane-associated particles supported the ruffled border membranes. Inside the actin sealing zone, membrane specializations were not always occupied with the ruffled border but also with other types of membranes. Some osteoclasts formed an actin ring but lacked the ruffled border projections. We report a unique and distinctive membrane modification of apatite-attached osteoclasts, i.e., the presence of dense aggregates of membrane-associated particles and related structures not found in the osteoclasts seeded on glass plates. Actin filament polarity in the podosomes was determined by decoration with myosin S1. The actin filament polarity within podosome appears to be oriented predominantly with its barbed ends toward the core, whereas the interconnecting F-actin appears to be mixed oriented. Two different types of clathrin plaques displayed different distributions: clathrin-dependent endocytosis was observed in the ruffled border regions, whereas flat clathrin sheets were found in the leading edge of lamellipodia and near podosomes. The clathrin sheets adhered to the apatite surface tightly on the ventral membranes overlaying the resorption lacunae. All these membrane specializations as mentioned above may indicate the functional variability of osteoclasts seeded on apatite.

In vitro and in vivo evaluation of carbonate apatite-collagen scaffolds with some cytokines for bone tissue engineering

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Sherman Salim

2015-01-01

Results and Conclusion: By histological observation and measurement of bone area ratio, CA-CS with cytokines showed higher bone formation ability (bFGF/CA-CS: 50.7 ± 7.3%, rh-BMP2/CA-CS: 54.2 ± 5.0% than other groups. From the limited results of this study, it is suggested that CA collagen scaffolds with some cytokines may become an attractive scaffold for bone regeneration.

Anisotropy in Bone Demineralization Revealed by Polarized Far-IR Spectroscopy

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Roman Schuetz

2015-04-01

Full Text Available Bone material is composed of an organic matrix of collagen fibers and apatite nanoparticles. Previously, vibrational spectroscopy techniques such as infrared (IR and Raman spectroscopy have proved to be particularly useful for characterizing the two constituent organic and inorganic phases of bone. In this work, we tested the potential use of high intensity synchrotron-based far-IR radiation (50–500 cm−1 to gain new insights into structure and chemical composition of bovine fibrolamellar bone. The results from our study can be summarized in the following four points: (I compared to far-IR spectra obtained from synthetic hydroxyapatite powder, those from fibrolamellar bone showed similar peak positions, but very different peak widths; (II during stepwise demineralization of the bone samples, there was no significant change neither to far-IR peak width nor position, demonstrating that mineral dissolution occurred in a uniform manner; (III application of external loading on fully demineralized bone had no significant effect on the obtained spectra, while dehydration of samples resulted in clear differences. (IV using linear dichroism, we showed that the anisotropic structure of fibrolamellar bone is also reflected in anisotropic far-IR absorbance properties of both the organic and inorganic phases. Far-IR spectroscopy thus provides a novel way to functionally characterize bone structure and chemistry, and with further technological improvements, has the potential to become a useful clinical diagnostic tool to better assess quality of collagen-based tissues.

Characterisation of mineralisation of bone and cartilage: X-ray diffraction and Ca and Sr K{sub {alpha}} X-ray fluorescence microscopy

Energy Technology Data Exchange (ETDEWEB)

Bradley, D.A. [Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford, Surrey, GU2 7XH (United Kingdom)], E-mail: d.a.bradley@surrey.ac.uk; Muthuvelu, P.; Ellis, R.E.; Green, E.M.; Attenburrow, D. [Biomedical Physics Group, School of Physics, University of Exeter, Exeter (United Kingdom); Barrett, R. [ESRF, BP 220, F-38043 Grenoble Cedex (France); Arkill, K.; Colridge, D.B.; Winlove, C.P. [Biomedical Physics Group, School of Physics, University of Exeter, Exeter (United Kingdom)

2007-10-15

Bone is a dynamic structure, constantly remodelling in response to changing mechanical and environmental factors. This is particularly evident in the mineral component encrusting the collagenous framework. The mineral is principally in the form of calcium apatite, but calcium can exchange with strontium, both during the cellular processes of mineralisation and resorption and by passive exchange with the deposited crystals. Mineralisation is generally characterized by densitometry, but because of the differences in absorption cross sections of calcium and strontium it can be misleading in studies of composition. In this work we have used X-ray diffraction to identify calcium and strontium apatite and X-ray fluorescence to quantify strontium and calcium distribution. With the beam characteristics available from synchrotron radiation, this has enabled us to obtain microscopic resolution on thin sections of bone and cartilage from the equine metacarpophalangeal joint. Two issues have been investigated; the first is the distribution of mineral in the bone-cartilage interface and within individual trabeculae. In trabecular bone the ratio of strontium to calcium concentration was typically 0.0035 {+-} 0.0020, and higher by a factor of {approx}3 at the periphery than in the centre of a trabeculum (possibly reflecting the more rapid turnover of mineral in the surface layer). In the dense subchondral bone the ratio was similar, approximately doubling in the calcified cartilage. The second objective was to explore the changes in mineralisation associated with development of osteoarthrosis. We analysed lesions showing cartilage thinning and changes in the trabecular organization and density of the underlying bone. At the centre of the lesion the ratio of strontium to calcium was much lower than that in normal tissue, although the calcified cartilage still showed a higher ratio than the underlying bone. In the superficially normal tissue around the lesion the calcified

Regulation of physicochemical properties, osteogenesis activity, and fibroblast growth factor-2 release ability of β-tricalcium phosphate for bone cement by calcium silicate

International Nuclear Information System (INIS)

Su, Ching-Chuan; Kao, Chia-Tze; Hung, Chi-Jr; Chen, Yi-Jyun; Huang, Tsui-Hsien; Shie, Ming-You

2014-01-01

β-Tricalcium phosphate (β-TCP) is an osteoconductive material. For this research we have combined it with a low degradation calcium silicate (CS) to enhance its bioactive and osteostimulative properties. To check its effectiveness, a series of β-TCP/CS composites with different ratios were prepared to make new bioactive and biodegradable biocomposites for bone repair. Formation of bone-like apatite, the diametral tensile strength, and weight loss of composites were considered before and after immersion in simulated body fluid (SBF). In addition, we also examined the effects of fibroblast growth factor-2 (FGF-2) released from β-TCP/CS composites and in vitro human dental pulp cell (hDPC) and studied its behavior. The results showed that the apatite deposition ability of the β-TCP/CS composites was enhanced as the CS content was increased. For composites with more than 50% CS contents, the samples were completely covered by a dense bone-like apatite layer. At the end of the immersion point, weight losses of 19%, 24%, 33%, 42%, and 51% were observed for the composites containing 0%, 30%, 50%, 70% and 100% β-TCP cements, respectively. In vitro cell experiments show that the CS-rich composites promote human dental pulp cell (hDPC) proliferation and differentiation. However, when the CS quantity in the composite is less than 70%, the amount of cells and osteogenesis protein of hDPCs was stimulated by FGF-2 released from β-TCP/CS composites. The combination of FGF-2 in degradation of β-TCP and osteogenesis of CS gives a strong reason to believe that these calcium-based composite cements may prove to be promising bone repair materials. - Highlights: • CS improved physicochemical properties and osteogenic activity of β-TCP. • The higher the CS in the cement, the shorter the setting time and the higher the DTS. • The cell behavior was stimulated by FGF-2 released from composite containing 50% CS. • β-TCP/CS composite with FGF-2 has optimal properties for

Solubility of apatite in H2O-NaCl and silicate-bearing solutions at 0.7-3.0 GPa, 800° C

Science.gov (United States)

Antignano, A.; Manning, C. E.

2004-12-01

Apatite is a major reservoir for the rare-earth elements (REE) in the earth's crust. However, little is known about its solubility in metamorphic fluids. We measured the solubility of apatite in H2O-NaCl and silicate bearing fluids at 800° C and 1.0-2.0 GPa using a piston-cylinder apparatus with NaCl-graphite furnaces. A single Durango fluor-apatite crystal was loaded into a 1.6 mm OD Pt inner capsule, which was crimped and then placed in a 3.5 OD Pt outer capsule with ultra pure H2O and NaCl or powdered albite. Solubility was determined by the weight loss of the apatite grain after 24 hrs. In the H2O-NaCl experiments, total dissolved solids (TDS) were initially below detection (0.4 millimolal) between XNaCl= 0 and XNaCl= 0.025. At XNaCl= 0.035, solubility was 3.3(0.2) millimolal (errors are 1s), and it increased to 57.5(0.4) millimolal at XNaCl= 0.526. Our results show that there is an enhancement in apatite solubility with increasing pressure in pure H2O. Solubility is initially below detection at bearing solutions. This probably explains textures in which monazite mantles apatite, which are common in granulite metamorphic terranes, such as the Kiirunavaara magnetite-apatite ore.

About the Genetic Mechanisms of Apatites: A Survey on the Methodological Approaches

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Linda Pastero

2017-08-01

Full Text Available Apatites are properly considered as a strategic material owing to the broad range of their practical uses, primarily biomedical but chemical, pharmaceutical, environmental and geological as well. The apatite group of minerals has been the subject of a huge number of papers, mainly devoted to the mass crystallization of nanosized hydroxyapatite (or carboapatite as a scaffold for osteoinduction purposes. Many wet and dry methods of synthesis have been proposed. The products have been characterized using various techniques, from the transmission electron microscopy to many spectroscopic methods like IR and Raman. The experimental approach usually found in literature allows getting tailor made micro- and nano- crystals ready to be used in a wide variety of fields. Despite the wide interest in synthesis and characterization, little attention has been paid to the relationships between bulk structure and corresponding surfaces and to the role plaid by surfaces on the mechanisms involved during the early stages of growth of apatites. In order to improve the understanding of their structure and chemical variability, close attention will be focused on the structural complexity of hydroxyapatite (HAp, on the richness of its surfaces and their role in the interaction with the precursor phases, and in growth kinetics and morphology.

X-Ray Processing of ChaMPlane Fields: Methods and Initial Results for Selected Anti-Galactic Center Fields

Science.gov (United States)

Hong, JaeSub; van den Berg, Maureen; Schlegel, Eric M.; Grindlay, Jonathan E.; Koenig, Xavier; Laycock, Silas; Zhao, Ping

2005-12-01

We describe the X-ray analysis procedure of the ongoing Chandra Multiwavelength Plane (ChaMPlane) Survey and report the initial results from the analysis of 15 selected anti-Galactic center observations (90degusing custom-developed analysis tools appropriate for Galactic sources but also of general use: optimum photometry in crowded fields using advanced techniques for overlapping sources, rigorous astrometry and 95% error circles for combining X-ray images or matching to optical/IR images, and application of quantile analysis for spectral analysis of faint sources. We apply these techniques to 15 anti-Galactic center observations (of 14 distinct fields), in which we have detected 921 X-ray point sources. We present logN-logS distributions and quantile analysis to show that in the hard band (2-8 keV) active galactic nuclei dominate the sources. Complete analysis of all ChaMPlane anti-Galactic center fields will be given in a subsequent paper, followed by papers on sources in the Galactic center and bulge regions.

Correction: Mutsuzaki, H., et al. Improved Bonding of Partially Osteomyelitic Bone to Titanium Pins Owing to Biomimetic Coating of Apatite. Int. J. Mol. Sci. 2013, 14, 24366–24379.

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Hirotaka Mutsuzaki

2014-05-01

Full Text Available In the original version of the manuscript [1] there was an inadvertent error. The words “25 °C for 48 h” should be replaced with “25 °C for 24 h”. The authors carried out the coating experiments at 25 °C for 1, 3, 6, 12, 24 and 48 h. The apatite coatings formed at 25 °C for 24 and 48 h were found to be identical in physicochemical nature, which was revealed by SEM, EDX, XRD and chemical analysis. Thus, in the animal experiments, the authors used apatite-coated Ti pins fabricated at 25 °C for 24 h. Several corrections are thus required in the abstract, the main text, the figure legends, and the figures (Table 1. The authors would like to apologize for any inconvenience this may have caused to readers of the journal. [...

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

International Nuclear Information System (INIS)

Zeitler, P.K.; Herczeg, A.L.; McDougall, I.; Honda, M.

1987-01-01

The authors found a gem quality crystal of Durango fluorapatite to have a 4 He content consistent with complete retention of radiogenic helium since its formation at about 31 Ma. Isothermal heating and step-heating analysis reveal 4 He 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 (D 0 /a 2 ) = 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

Value of Combining Left Atrial Diameter and Amino-terminal Pro-brain Natriuretic Peptide to the CHA2DS2-VASc Score for Predicting Stroke and Death in Patients with Sick Sinus Syndrome after Pacemaker Implantation.

Science.gov (United States)

Mo, Bin-Feng; Lu, Qiu-Fen; Lu, Shang-Biao; Xie, Yu-Quan; Feng, Xiang-Fei; Li, Yi-Gang

2017-08-20

The CHA2DS2-VASc score is used clinically for stroke risk stratification in patients with atrial fibrillation (AF). We sought to investigate whether the CHA2DS2-VASc score predicts stroke and death in Chinese patients with sick sinus syndrome (SSS) after pacemaker implantation and to evaluate whether the predictive power of the CHA2DS2-VASc score could be improved by combining it with left atrial diameter (LAD) and amino-terminal pro-brain natriuretic peptide (NT-proBNP). A total of 481 consecutive patients with SSS who underwent pacemaker implantation from January 2004 to December 2014 in our department were included. The CHA2DS2-VASc scores were retrospectively calculated according to the hospital medical records before pacemaker implantation. The outcome data (stroke and death) were collected by pacemaker follow-up visits and telephonic follow-up until December 31, 2015. During 2151 person-years of follow-up, 46 patients (9.6%) suffered stroke and 52 (10.8%) died. The CHA2DS2-VASc score showed a significant association with the development of stroke (hazard ratio [HR] 1.45, 95% confidence interval [CI] 1.20-1.75, Ppacemaker implantation. The addition of LAD and NT-proBNP to the CHA2DS2-VASc score improved its predictive power for stroke and death, respectively, in this patient cohort. Future prospective studies are warranted to validate the benefit of adding LAD and NT-proBNP to the CHA2DS2-VASc score for predicting stroke and death risk in non-AF populations.

Thermal and electron stimulated luminescence of natural bones, commercial hydroxyapatite and collagen.

Science.gov (United States)

Roman-Lopez, J; Correcher, V; Garcia-Guinea, J; Rivera, T; Lozano, I B

2014-01-01

The luminescence (cathodoluminescence and thermoluminescence) properties of natural bones (Siberian mammoth and adult elephant), commercial hydroxyapatite and collagen were analyzed. Chemical analyses of the natural bones were determined using by Electron Probe Micro-Analysis (EMPA). Structural, molecular and thermal characteristics were determined by X-ray Diffraction (XRD), Raman spectroscopy and Differential Thermal and Thermogravimetric analysis (DTA-TG). Cathodoluminescence (CL) spectra of natural bones and collagen showed similar intense broad bands at 440 and 490 nm related to luminescence of the tetrahedral anion [Formula: see text] or structural defects. A weaker luminescence exhibited at 310 nm could be attributed to small amount of rare earth elements (REEs). Four luminescent bands at 378, 424, 468 and 576 nm were observed in the commercial hydroxyapatite (HAP). Both natural bones and collagen samples exhibited natural thermoluminescence (NTL) with well-defined glow curves whereas that the induced thermoluminescence (ITL) only appears in the samples of commercial hydroxyapatite and collagen. Additional explanations for the TL anomalous fading of apatite, as a crucial difficulty performing dosimetry and dating, are also considered. Copyright © 2013 Elsevier B.V. All rights reserved.

Development of a degradable cement of calcium phosphate and calcium sulfate composite for bone reconstruction

International Nuclear Information System (INIS)

Guo, H; Wei, J; Liu, C S

2006-01-01

A new type of composite bone cement was prepared and investigated by adding calcium sulfate (CS) to calcium phosphate cement (CPC). This composite cement can be handled as a paste and easily shaped into any contour, which can set within 5-20 min, the setting time largely depending on the liquid-solid (L/S) ratio; adding CS to CPC had little effect on the setting time of the composite cements. No obvious temperature increase and pH change were observed during setting and immersion in simulated body fluid (SBF). The compressive strength of the cement decreased with an increase in the content of CS. The degradation rate of the composite cements increased with time when the CS content was more than 20 wt%. Calcium deficient apatite could form on the surface of the composite cement because the release of calcium into SBF from the dissolution of CS and the apatite of the cement induced the new apatite formation; increasing the content of CS in the composite could improve the bioactivity of the composite cements. The results suggested that composite cement has a reasonable setting time, excellent degradability and suitable mechanical strength and bioactivity, which shows promising prospects for development as a clinical cement

Biological responses of brushite-forming Zn- and ZnSr- substituted beta-tricalcium phosphate bone cements

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S Pina

2010-09-01

Full Text Available The core aim of this study was to investigate zinc (Zn- and zinc and strontium (ZnSr-containing brushite-forming beta-tricalcium phosphate (TCP cements for their effects on proliferation and differentiation of osteoblastic-like cells (MC3T3-E1 cell line as well as for their in vivo behaviour in trabecular bone cylindrical defects in a pilot study. In vitro proliferation and maturation responses of MC3T3-E1 osteoblastic-like cells to bone cements were studied at the cellular and molecular levels. The Zn- and Sr-containing brushite cements were found to stimulate pre-osteoblastic proliferation and osteoblastic maturation. Indeed, MC3T3-E1 cells exposed to the powdered cements had increased proliferative rates and higher adhesiveness capacity, in comparison to control cells. Furthermore, they exhibited higher alkaline phosphatase (ALP activity and increased Type-I collagen secretion and fibre deposition into the extracellular matrix. Proliferative and collagen deposition properties were more evident for cells grown in cements doped with Sr. The in vivo osteoconductive propertiesof the ZnCPC and ZnSrCPC cements were also pursued. Histological and histomorphometric analyses were performed at 1 and 2 months after implantation, using carbonated apatite cement (Norian SRS® as control. There was no evidence of cement-induced adverse foreign body reactions, and furthermore ZnCPC and ZnSrCPC cements revealed better in vivo performance in comparison to the control apatite cement. Additionally, the presence of both zinc and strontium resulted in the highest rate of new bone formation. These novel results indicate that the investigated ZnCPC and ZnSrCPC cements are both biocompatible and osteoconductive, being good candidate materials to use as bone substitutes.

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

Energy Technology Data Exchange (ETDEWEB)

Prywer, Jolanta, E-mail: jolanta.prywer@p.lodz.pl [Institute of Physics, Lodz University of Technology, ul. Wólczańska 219, 93-005 Łódź (Poland); Olszynski, Marcin [Institute of Physics, Lodz University of Technology, ul. Wólczańska 219, 93-005 Łódź (Poland); Mielniczek-Brzóska, Ewa [Institute of Chemistry, Environment Protection and Biotechnology, Jan Długosz University of Częstochowa, ul. Armii Krajowej 13/15, 42-200 Częstochowa (Poland)

2015-11-15

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 Ca{sup 2+} ions and causes the formation of CaCit{sup −} and Ca{sub 10}(PO{sub 4}){sub 6}CO{sub 3} complexes. Trisodium citrate binds Ca{sup 2+} ions in the range of pH from 6 to 9.5 for which carbonate apatite is favored to be formed. - Highlights: • Trisodium citrate (TC) increases induction time of carbonate apatite (CA) formation. • TC decreases the efficiency of CA precipitation. • The inhibitory effect of TC is explained in base of chemical speciation analysis. • The inhibitory effect is mainly related with the fact that TC binds Ca{sup 2+} ions. • TC binds Ca{sup 2+} ions in the range of pH from 6 to 9.5 for which CA is formed.

Ammonia IRMS-TPD measurements and DFT calculation on acidic hydroxyl groups in CHA-type zeolites.

Science.gov (United States)

Suzuki, Katsuki; Sastre, German; Katada, Naonobu; Niwa, Miki

2007-12-07

Brønsted acidity of H-chabazite (CHA) zeolites (Si : Al(2) = 4.2) was investigated by means of ammonia infrared-mass spectrometry/temperature-programmed desorption (IRMS-TPD) methods and density functional calculations. Four IR bands were observed at 3644, 3616, 3575 and 3538 cm(-1), and they were ascribable to the acidic OH groups on four nonequivalent oxygen sites in the CHA structure. The absorption band at 3538 cm(-1) was attributed to the O(4)H in the 6-membered ring (MR), and ammonia adsorption energy (DeltaU) of this OH group was the lowest among the 4 kinds of OH groups. The other 3 bands were assigned to the acidic OH groups in 8MR. It was observed that the DeltaU in 8 and 6MR were 131 (+/-3) and 101 kJ mol(-1), respectively. On the other hand, the density functional theory (DFT) calculations within periodic boundary conditions yielded the adsorption energies on these OH groups in 8 and 6MR to be ca. 130 and 110 kJ mol(-1), respectively, in good agreement with the experimentally-observed values.

Preservation of rodent bones from El Harhoura 2 cave (Morocco, Neolithic - Middle Palaeolithic): Microstructure, mineralogy, crystallinity and composition

Science.gov (United States)

Farre, Bastien; Massard, Pierre; Nouet, Julius; Dauphin, Yannicke

2014-04-01

Thin sections, scanning electron microscopy (SEM), diffraction X (DRX) and infrared spectrometry (FTIR) have been used to study the structure, mineralogy, crystallinity and bulk composition of fossil rodent long bones extracted from a succession of sedimentary layers in a cave from Morocco (Neolithic - Middle Palaeolithic, El Harhoura 2). The microstructure of fossil bones is well-preserved at this scale of observation, and encrusted deposits are rare. All bones are preserved in apatite, but the crystallinity is modified, as well as the crystallite shape, the organic content and the organic-mineral ratio. No fluor enrichment has been observed. Alone or together, the studied parameters do not show a regular trend from the upper to the lower layers of the cave. The preservation of the fossil bones does not confirm the sequence of arid and humid periods inferred from taphonomic analyses.

"Fabrication of arbitrarily shaped carbonate apatite foam based on the interlocking process of dicalcium hydrogen phosphate dihydrate".

Science.gov (United States)

Sugiura, Yuki; Tsuru, Kanji; Ishikawa, Kunio

2017-08-01

Carbonate apatite (CO 3 Ap) foam with an interconnected porous structure is highly attractive as a scaffold for bone replacement. In this study, arbitrarily shaped CO 3 Ap foam was formed from α-tricalcium phosphate (α-TCP) foam granules via a two-step process involving treatment with acidic calcium phosphate solution followed by hydrothermal treatment with NaHCO 3 . The treatment with acidic calcium phosphate solution, which is key to fabricating arbitrarily shaped CO 3 Ap foam, enables dicalcium hydrogen phosphate dihydrate (DCPD) crystals to form on the α-TCP foam granules. The generated DCPD crystals cause the α-TCP granules to interlock with each other, inducing an α-TCP/DCPD foam. The interlocking structure containing DCPD crystals can survive hydrothermal treatment with NaHCO 3 . The arbitrarily shaped CO 3 Ap foam was fabricated from the α-TCP/DCPD foam via hydrothermal treatment at 200 °C for 24 h in the presence of a large amount of NaHCO 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

Comments About The New Rhetoric Theory Of Chaïm Perelman

Directory of Open Access Journals (Sweden)

Veronica Calado

2016-11-01

Full Text Available This essay pretends to demonstrate how the issue of the interpretation of legal norms was treated in the New Rhetoric of Chaïm Perelman. The theory emerged in the 1950´s criticizing juridical positivism and bringing back the possibility of reinsertion of valuational matters in the application of the law. With the scope of not compromising legal predictability, notions like equity and reasonability where hitched to the concept. Furthermore, the essay aimed, with the collation of literary works about the theme, to analyze the possibility of applying the New Rhetoric theory in the Brazilian Legal Order, The method utilized was the critic- deductive.

An EPR spectrum decomposition study of precipitated carbonated apatites (NCAP) dried at 25 deg C: adsorption of molecules from the atmosphere on the apatite powders

International Nuclear Information System (INIS)

Moens, P.D.W.; Callens, F.J.; Verbeeck, R.M.H.; Naessens, D.E.

1993-01-01

The effect of storage under ambient conditions on the Electron Paramagnetic Resonance (EPR) spectrum of X-irradiated sodium and carbonate containing synthetic apatites has been studied. A first series of samples was X-irradiated shortly after preparation and drying at 25 o C and investigated by means of EPR. The observed spectra were decomposed in terms of five theoretical curves representing an O - radical, two CO 3 - radicals (surface and bulk) and two CO 2 - radicals (surface and bulk). Afterwards, a second series of the same samples which was stored under ambient conditions for a long period, was also X-irradiated and examined with EPR. The same five radicals were found, but in different relative amounts. It appeared that the relative contributions of the two carbon containing surface radicals increased in comparison with the corresponding bulk radicals. This is explained by an adsorption of molecules from the atmosphere on the surface of the apatite powder. (author)

Effects of lead shot ingestion on bone mineralization in a population of red-legged partridge (Alectoris rufa)

International Nuclear Information System (INIS)

Álvarez-Lloret, Pedro; Rodríguez-Navarro, Alejandro B.; Romanek, Christopher S.; Ferrandis, Pablo; Martínez-Haro, Mónica; Mateo, Rafael

2014-01-01

The effect of lead (Pb) toxicity on bone mineralization was investigated in a wild population of red-legged partridge (Alectoris rufa) inhabiting a farmland area contaminated with Pb-shot from recreational hunting activities in Albacete, a southeastern province of Spain. Femora from 40 specimens of red-legged partridge were analyzed for Pb by graphite furnace atomic absorption spectroscopy (GF-AAS), and for bone composition by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The FTIR and DRX data of bone were analyzed in detail to determine possible alterations in bone mineral chemistry and crystallinity due to Pb toxicity. Results showed a marked decrease in the degree of mineralization as Pb concentrations in bone tissue increased while XRD analyses showed that the crystallinity of apatite crystals increased with the Pb load in bone. These load-dependent effects are indicative that Pb contamination altered bone remodeling by reducing new bone mineral formation and demonstrate that bone quality is a sensitive indicator of adverse effects on wild bird populations exposed to Pb pollution. - Highlights: •The effect of Pb toxicity on bone mineralization was investigated in partridges. •Lead exposure decreased bone mineralization degree. •Demonstrated usefulness of FTIR and DRX to evaluate alterations in bone chemistry and crystallinity by Pb exposure

Effects of lead shot ingestion on bone mineralization in a population of red-legged partridge (Alectoris rufa)

Energy Technology Data Exchange (ETDEWEB)

Álvarez-Lloret, Pedro, E-mail: pedroalvarez@geol.uniovi.es [Department of Mineralogy and Petrology, University of Granada, Avd. Fuentenueva s/n, 18002 Granada (Spain); Departament of Geology, University of Oviedo, C/Jesús Arias de Velasco, s/n, 33005 Oviedo (Spain); Rodríguez-Navarro, Alejandro B. [Department of Mineralogy and Petrology, University of Granada, Avd. Fuentenueva s/n, 18002 Granada (Spain); Romanek, Christopher S. [Department of Earth and Environmental Sciences, University of Kentucky, Lexington, KY (United States); Ferrandis, Pablo [Department of Plant Production and Agricultural Technology, E.T.S. Ingenieros Agrónomos, University of Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete (Spain); Martínez-Haro, Mónica [Instituto de Investigación en Recursos Cinegéticos, IREC (CSIC, UCLM, JCCM), Ronda de Toledo s/n, 13005 Ciudad Real (Spain); IMAR-Instituto do Mar, Department of Life Sciences, University of Coimbra, 3004-517 Coimbra (Portugal); Mateo, Rafael [Instituto de Investigación en Recursos Cinegéticos, IREC (CSIC, UCLM, JCCM), Ronda de Toledo s/n, 13005 Ciudad Real (Spain)

2014-01-01

The effect of lead (Pb) toxicity on bone mineralization was investigated in a wild population of red-legged partridge (Alectoris rufa) inhabiting a farmland area contaminated with Pb-shot from recreational hunting activities in Albacete, a southeastern province of Spain. Femora from 40 specimens of red-legged partridge were analyzed for Pb by graphite furnace atomic absorption spectroscopy (GF-AAS), and for bone composition by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The FTIR and DRX data of bone were analyzed in detail to determine possible alterations in bone mineral chemistry and crystallinity due to Pb toxicity. Results showed a marked decrease in the degree of mineralization as Pb concentrations in bone tissue increased while XRD analyses showed that the crystallinity of apatite crystals increased with the Pb load in bone. These load-dependent effects are indicative that Pb contamination altered bone remodeling by reducing new bone mineral formation and demonstrate that bone quality is a sensitive indicator of adverse effects on wild bird populations exposed to Pb pollution. - Highlights: •The effect of Pb toxicity on bone mineralization was investigated in partridges. •Lead exposure decreased bone mineralization degree. •Demonstrated usefulness of FTIR and DRX to evaluate alterations in bone chemistry and crystallinity by Pb exposure.

Quantitative determination of bone mineral concentrations using quotient densitometry in patients under long-term anticonvulsant therapy

International Nuclear Information System (INIS)

Schulz, H.

1980-01-01

The effect on bone mineral concentration of anticonvulsive long-term therapy was investigated in order to find out if there is a relation between the occurence and extent of osteomalacial lesions on the one hand and the type and time of application of anticonvulsants. The hydroxyl apatite content was determined by X-ray densitometry. The method is considered to be suitable for yearly skeletal monitoring of epilepticians treated with anticonvulsants. (orig./HP) [de

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)

He, U, and Th Depth Profiling of Apatite and Zircon Using Laser Ablation Noble Gas Mass Spectrometry and SIMS

Science.gov (United States)

Monteleone, B. D.; van Soest, M. C.; Hodges, K. V.; Hervig, R.; Boyce, J. W.

2008-12-01

Conventional (U-Th)/He thermochronology utilizes single or multiple grain analyses of U- and Th-bearing minerals such as apatite and zircon and does not allow for assessment of spatial variation in concentration of He, U, or Th within individual crystals. As such, age calculation and interpretation require assumptions regarding 4He loss through alpha ejection, diffusive redistribution of 4He, and U and Th distribution as an initial condition for these processes. Although models have been developed to predict 4He diffusion parameters, correct for the effect of alpha ejection on calculated cooling ages, and account for the effect of U and Th zonation within apatite and zircon, measurements of 4He, U, and Th distribution have not been combined within a single crystal. We apply ArF excimer laser ablation, combined with noble gas mass spectrometry, to obtain depth profiles within apatite and zircon crystals in order to assess variations in 4He concentration with depth. Our initial results from pre-cut, pre-heated slabs of Durango apatite, each subjected to different T-t schedules, suggest a general agreement of 4He profiles with those predicted by theoretical diffusion models (Farley, 2000). Depth profiles through unpolished grains give reproducible alpha ejection profiles in Durango apatite that deviate from alpha ejection profiles predicted for ideal, homogenous crystals. SIMS depth profiling utilizes an O2 primary beam capable of sputtering tens of microns and measuring sub-micron resolution variation in [U], [Th], and [Sm]. Preliminary results suggest that sufficient [U] and [Th] zonation is present in Durango apatite to influence the form of the 4He alpha ejection profile. Future work will assess the influence of measured [U] and [Th] zonation on previously measured 4He depth profiles. Farley, K.A., 2000. Helium diffusion from apatite; general behavior as illustrated by Durango fluorapatite. J. Geophys. Res., B Solid Earth Planets 105 (2), 2903-2914.

Multiple Stage Ore Formation in the Chadormalu Iron Deposit, Bafq Metallogenic Province, Central Iran: Evidence from BSE Imaging and Apatite EPMA and LA-ICP-MS U-Pb Geochronology

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Hassan Heidarian

2018-02-01

Full Text Available The Chadormalu magnetite-apatite deposit in Bafq metallogenic province, Central Iran, is hosted in the late Precambrian-lower Cambrian volcano-sedimentary rocks with sodic, calcic, and potassic alterations characteristic of iron oxide copper-gold (IOCG and iron oxide-apatite (IOA ore systems. Apatite occurs as scattered irregular veinlets and disseminated grains, respectively, within and in the marginal parts of the main ore-body, as well as apatite-magnetite veins in altered wall rocks. Textural evidence (SEM-BSE images of these apatites shows primary bright, and secondary dark areas with inclusions of monazite/xenotime. The primary, monazite-free fluorapatite contains higher concentrations of Na, Si, S, and light rare earth elements (LREE. The apatite was altered by hydrothermal events that led to leaching of Na, Si, and REE + Y, and development of the dark apatite. The bright apatite yielded two U-Pb age populations, an older dominant age of 490 ± 21 Ma, similar to other iron deposits in the Bafq district and associated intrusions, and a younger age of 246 ± 17 Ma. The dark apatite yielded a U-Pb age of 437 ± 12 Ma. Our data suggest that hydrothermal magmatic fluids contributed to formation of the primary fluorapatite, and sodic and calcic alterations. The primary apatite reequilibrated with basinal brines in at least two regional extensions and basin developments in Silurian and Triassic in Central Iran.

Formation of A-type granites in the Lower Yangtze River Belt: A perspective from apatite geochemistry

Science.gov (United States)

Jiang, Xiao-Yan; Li, He; Ding, Xing; Wu, Kai; Guo, Jia; Liu, Ji-Qiang; Sun, Wei-Dong

2018-04-01

Apatite is ubiquitous in A-type granites, and can be used to elucidate the volatile contents of the silicate melt, which reflect its source characteristics. A-type granites have been recognized as a distinct group of granites. A1- and A2-type subgroups are produced under different extensional settings. However, the details of the mechanisms behind the distinctive geochemical characteristics of A1- and A2-type granites remain obscure. Belts of Cretaceous A1- and A2-type granites occur along the Lower Yangtze River Belt in eastern China. Here we investigated the major and trace element compositions of apatites from contemporary A1- and A2-type granites at different localities along the Lower Yangtze River Belt, in order to decipher their discrepant source processes. Apatites from A1- and A2-type granites show similar major and trace elements, but differ in their F and Cl concentrations. Apatites from A1-type granites in the eastern part of the Lower Yangtze River Belt have much lower F and higher Cl concentrations compared to A2-type granites in the western part. Moreover, from the east to the west, the F concentrations of apatites from A1-type granites increase, while the Cl concentrations decline. In a subducted plate, F is retained by amphibole, chlorite, serpentine and mica minerals through the amphibolite stage, and finally by phengite and lawsonite during the eclogite stage, whereas, Cl is controlled by amphibole, chlorite and serpentine. The high and varied Cl concentrations in A1 subgroup apatites, therefore, may be attributed to the breakdown of amphibole, chlorite and/or serpentine decomposition during partial melting of subducted oceanic crust releasing a large amount of Cl at shallower depth. In contrast, F is transported to deeper depths in the subducted oceanic crust, and released through breakdown of phengite and lawsonite, making an important contribution to the formation of A2-type granites. Apatites from A1- and A2-type granite samples show regular

Main properties of nanocrystalline hydroxyapatite as a bone graft material in treatment of periodontal defects. A review of literature

International Nuclear Information System (INIS)

Bayani, Mojtaba; Torabi, Sepehr; Shahnaz, Aysan; Pourali, Mohammad

2017-01-01

This study aims to provide a literature review on nanocrystalline hydroxyapatite (n-HA). n-HA constitutes the principle inorganic part of hard tissues. Therefore, preparation of commercial synthetic analogues, the so-called ‘biomimetic’, has gained a lot of attention since it can precisely mimic the physicochemical features of biological apatite compounds. Due to its improved osseointegrative properties, n-HA may represent a promising class of bone graft materials. n-HA binds to the bone and by stimulation of osteoblast activity and enhancing local growth factors it improves bone healing. Periodontitis is an inflammatory condition in response to microbial plaque that leads to periodontal tissue destruction and osseous defects in alveolar bone. A review of the extant literature reveals that n-HA has certain advantages in periodontal tissue regeneration including minimal patient morbidity, better biocompatibility, and lack of toxicity

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

International Nuclear Information System (INIS)

Vilchis G, J.

2013-01-01

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 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)

Decreased Renal Function Is Associated with Elevated CHA2DS2VASC and R2CHADS2 Scores in Non-Valvular Atrial Fibrillation Patients Presenting with Stroke.

Science.gov (United States)

Vindhyal, Mohinder; Vindhyal, Shravani R; Haneke, Travis; Ndunda, Paul M; Eid, Freidy; Kallail, K James

2017-12-11

Introduction Atrial fibrillation (AF), the most common cardiac arrhythmia, affects approximately 2.3 million patients in the United States, costing around $26 billion. Atrial fibrillation is associated with a two- to seven-fold increased risk of stroke, one of the most serious complications. Chronic kidney disease affects approximately 13% of the US population and has been associated with higher rates of AF than the general population. In patients with chronic kidney disease (CKD), the risk of stroke increases as the glomerular filtration rate (GFR) decreases, especially in CKD stages three and four. Several risks stratification scores such as CHADS2 (congestive heart failure, hypertension, age, diabetes mellitus, stroke), CHA2DS2VASc (congestive heart failure, hypertension, age, diabetes mellitus, stroke, vascular disease, age, sex), and R2CHADS2 (renal failure, congestive heart failure, age, diabetes, stroke) scores are used for stroke risk assessment in patients with non-valvular atrial fibrillation (NVAF). This study investigates the association between renal functions and risk stratification scoring systems in patients with non-valvular AF presenting with stroke. Methods Using the convenience sampling method, 171 subjects were selected from the eligible population (n = 386). A Pearson product-moment correlation coefficient was calculated to determine the association between the GFR and each of the CHA2DS2VASc and R2CHADS2 scores. In addition, a Pearson product-moment correlation coefficient was calculated to determine the association between the CHA2DS2VASc and R2CHADS2 scores. Results The selected population represented 44.3% of the eligible subjects. Of these, 88% were Caucasian, 60% were female, and the mean age was 78 years. The mean CHA2DS2VASc score was six (range 2-9). The mean eGFR was 69.77 (range 6-108). Both the mode and the median CHA2DS2VASc score was four (range 2-8). A weak, but significant, negative correlation was found between renal

The efficacy of hydrothermally obtained carbonated hydroxyapatite in healing alveolar bone defects in rats with or without corticosteroid treatment.

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Marković, Dejan; Jokanović, Vukoman; Petrović, Bojan; Perić, Tamara; Vukomanović, Biserka

2014-05-01

Autogenous bone grafting has been the gold standard in clinical cases when bone grafts are required for bone defects in dentistry. The study was undertaken to evaluate multilevel designed carbonated hydroxyapatite (CHA) obtained by hydrothermal method, as a bone substitute in healing bone defects with or without corticosteroid treatment in rats as assessed by histopathologic methods. Bone defects were created in the alveolar bone by teeth extraction in 12 rats. The animals were initially divided into two groups. The experimental group was pretreated with corticosteroids: methylprednisolone and dexamethasone, intramuscularly, while the control group was without therapy. Posterior teeth extraction had been performed after the corticosteroid therapy. The extraction defects were fulfilled with hydroxyapatite with bimodal particle sizes in the range of 50-250 μm and the sample from postextocactional defect of the alveolar bone was analyzed pathohystologically. The histopatological investigations confirmed the biologic properties of the applied material. The evident growth of new bone in the alveolar ridge was clearly noticed in both groups of rats. Carbonated HA obtained by hydrothermal method promoted bone formation in the preformed defects, confirming its efficacy for usage in bone defects. Complete resorption of the material's particles took place after 25 weeks. Hydroxyapatite completely meets the clinical requirements for a bone substitute material. Due to its microstructure, complete resorption took place during the observation period of the study. Corticosteroid treatment did not significantly affect new bone formation in the region of postextractional defects.

Value of Combining Left Atrial Diameter and Amino-terminal Pro-brain Natriuretic Peptide to the CHA2DS2-VASc Score for Predicting Stroke and Death in Patients with Sick Sinus Syndrome after Pacemaker Implantation

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Bin-Feng Mo

2017-01-01

Conclusions: CHA2DS2-VASc score is valuable for predicting stroke and death risk in patients with SSS after pacemaker implantation. The addition of LAD and NT-proBNP to the CHA2DS2-VASc score improved its predictive power for stroke and death, respectively, in this patient cohort. Future prospective studies are warranted to validate the benefit of adding LAD and NT-proBNP to the CHA2DS2-VASc score for predicting stroke and death risk in non-AF populations.

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

Science.gov (United States)

Szubert, M; Adamska, K; Szybowicz, M; Jesionowski, T; Buchwald, T; Voelkel, A

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. © 2013.

Hydroxyapatite additive influenced the bioactivity of bioactive nano-titania ceramics and new bone-forming capacity

Energy Technology Data Exchange (ETDEWEB)

Li Zhensheng [Third Military Medical University, College of Biomedical Engineering and Medical Imaging (China); Yang Xiaozhan [Chongqing University of Technology, School of Optoelectronic Information (China); Guo Hongfeng [Third Military Medical University, Tissue Engineering Research Center of Chongqing, Department of Anatomy, College of Basic Medical Sciences (China); Yang Xiaochao; Sun Lili [Third Military Medical University, College of Biomedical Engineering and Medical Imaging (China); Dong Shiwu, E-mail: shiwudong@gmail.com [Third Military Medical University, Tissue Engineering Research Center of Chongqing, Department of Anatomy, College of Basic Medical Sciences (China)

2012-09-15

Bioceramics plays an important role in bone-substitutes. In this study, titania porous ceramics with excellent bioactivity were prepared using hydroxyapatite (HA, 10 vol.% contents) as a grain growth inhibitor. The pure TiO{sub 2} porous ceramics were also prepared as a control. After sintered at 1,000 Degree-Sign C with a pressureless sintering method, the particle size of the pure TiO{sub 2} and TiO{sub 2}/HA (10 vol.%) porous ceramics were 450 and 310 nm, respectively. Each of the porous ceramics presented numerous pores, which were cross-connected. The size of the pores ranged from 100 to 300 {mu}m. There were also profuse micropores inside the pore wall and between the particles. A SBF soaking experiment demonstrated that the HA additive played an important role in promoting apatite formation. The cell proliferation demonstrated that osteoblasts on the TiO{sub 2}/HA (10 vol.%) porous ceramics proliferated faster than that on the pure TiO{sub 2} ceramics. The histological sections and EDX assay results of the two porous ceramics also illustrated that TiO{sub 2}/HA (10 vol.%) composite ceramics combined with Ca and P elements induced much better apatite formation than that of the pure TiO{sub 2} ceramics. These results indicated that titania ceramics combined with HA holds great promise for bone-substitutes.

A combined PIXE-PIGE approach for the assessment of the diagenetic state of cremated bones submitted to AMS radiocarbon dating

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Quarta, Gianluca; Calcagnile, Lucio; D'Elia, Marisa; Maruccio, Lucio; Gaballo, Valentina; Caramia, Annalisa

2013-01-01

Bone samples from a Bronze age necropolis in Northern Italy, exposed to different combustion temperatures, were submitted to XRD (X-ray Diffraction), PIXE (Particle Induced X-ray Emission) and PIGE (Particle Induced Gamma Ray Emission) analyses in order to obtain information about their diagenetic state. Structural carbonate was then extracted by acid hydrolysis and used for 14C-AMS (Accelerator Mass Spectrometry) dating. These analytical techniques permitted the study of the effects of the combustion temperature on the crystallinity of the bone apatite and on its elemental chemical composition in terms of major, minor and trace elements. The results indicate that combustion at temperatures above ∼700 °C induces changes in the bone crystalline structure, reducing the diagenetic uptake of elements from the burial environment.

A new hydroxyapatite-based biocomposite for bone replacement

Energy Technology Data Exchange (ETDEWEB)

Bellucci, Devis, E-mail: devis.bellucci@unimore.it [Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Via Vignolese 905, 41125 Modena (Italy); Sola, Antonella [Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Via Vignolese 905, 41125 Modena (Italy); Gazzarri, Matteo; Chiellini, Federica [Laboratory of Bioactive Polymeric Materials for Biomedical and Environmental Applications (BIOlab) and UdR INSTM, Department of Chemistry and Industrial Chemistry, University of Pisa, Via Vecchia Livornese 1291, 56122S. Piero a Grado, Pisa (Italy); Cannillo, Valeria [Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Via Vignolese 905, 41125 Modena (Italy)

2013-04-01

Since the 1970s, various types of ceramic, glass and glass–ceramic materials have been proposed and used to replace damaged bone in many clinical applications. Among them, hydroxyapatite (HA) has been successfully employed thanks to its excellent biocompatibility. On the other hand, the bioactivity of HA and its reactivity with bone can be improved through the addition of proper amounts of bioactive glasses, thus obtaining HA-based composites. Unfortunately, high temperature treatments (1200 °C ÷ 1300 °C) are usually required in order to sinter these systems, causing the bioactive glass to crystallize into a glass–ceramic and hence inhibiting the bioactivity of the resulting composite. In the present study novel HA-based composites are realized and discussed. The samples can be sintered at a relatively low temperature (800 °C), thanks to the employment of a new glass (BG{sub C}a) with a reduced tendency to crystallize compared to the widely used 45S5 Bioglass®. The rich glassy phase, which can be preserved during the thermal treatment, has excellent effects in terms of in vitro bioactivity; moreover, compared to composites based on 45S5 Bioglass® having the same HA/glass proportions, the samples based on BG{sub C}a displayed an earlier response in terms of cell proliferation. - Highlights: ► New apatite/bioglass composites are proposed and sintered at low temperature. ► The samples' glassy phase is preserved and the apatite decomposition is avoided. ► The rich glassy phase in the samples results in an excellent bioactivity. ► The samples are able to support cell adhesion and proliferation. ► The samples support faster cell proliferation compared to 45S5Bioglass-composites.

A new hydroxyapatite-based biocomposite for bone replacement

International Nuclear Information System (INIS)

Bellucci, Devis; Sola, Antonella; Gazzarri, Matteo; Chiellini, Federica; Cannillo, Valeria

2013-01-01

Since the 1970s, various types of ceramic, glass and glass–ceramic materials have been proposed and used to replace damaged bone in many clinical applications. Among them, hydroxyapatite (HA) has been successfully employed thanks to its excellent biocompatibility. On the other hand, the bioactivity of HA and its reactivity with bone can be improved through the addition of proper amounts of bioactive glasses, thus obtaining HA-based composites. Unfortunately, high temperature treatments (1200 °C ÷ 1300 °C) are usually required in order to sinter these systems, causing the bioactive glass to crystallize into a glass–ceramic and hence inhibiting the bioactivity of the resulting composite. In the present study novel HA-based composites are realized and discussed. The samples can be sintered at a relatively low temperature (800 °C), thanks to the employment of a new glass (BG C a) with a reduced tendency to crystallize compared to the widely used 45S5 Bioglass®. The rich glassy phase, which can be preserved during the thermal treatment, has excellent effects in terms of in vitro bioactivity; moreover, compared to composites based on 45S5 Bioglass® having the same HA/glass proportions, the samples based on BG C a displayed an earlier response in terms of cell proliferation. - Highlights: ► New apatite/bioglass composites are proposed and sintered at low temperature. ► The samples' glassy phase is preserved and the apatite decomposition is avoided. ► The rich glassy phase in the samples results in an excellent bioactivity. ► The samples are able to support cell adhesion and proliferation. ► The samples support faster cell proliferation compared to 45S5Bioglass-composites

The Cosmological Vision of the Yoruba-Idààcha of Benin Republic (West Africa): A Light on Yoruba History and Culture

Science.gov (United States)

Sègla, Aimé Dafon

The essay examines Idààcha cosmological vision as a kind of incorporation of Yoruba cosmology. It shows a process where the two strands, that is to say, knowledge and belief can not be readily distinguished. The divinatory traditional calendar is indeed based on a scale of fixed number values whose definitions are drawn from the concepts early traditional people have of the universe. Thus, the signification of the terms that designate entities such as angle, circle, center of the circle, midnight, time zone, the number of days in a week, etc., in the Yoruba dialect Idààcha, mirrors cosmological standards. These words constitute a landscape of memory shedding light on early Yoruba culture and history. Hence, Idààcha being a significant western periphery of the Yoruba region, we examine why its divinatory calendar would preserve an older spatio-temporal logic, beyond Ifè and Oyo revisionism in Yoruba history. Finally, the article points out that the translation of spatial and geometrical relations into temporal terms and vice-versa may suggest a new indexical approach to the study of cosmology in relation to the human body. As the body is in the mind, we say in relation to the human mind.

A gacS deletion in Pseudomonas aeruginosa cystic fibrosis isolate CHA shapes its virulence.

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Khady Mayebine Sall

Full Text Available Pseudomonas aeruginosa, a human opportunistic pathogen, is capable of provoking acute and chronic infections that are associated with defined sets of virulence factors. During chronic infections, the bacterium accumulates mutations that silence some and activate other genes. Here we show that the cystic fibrosis isolate CHA exhibits a unique virulence phenotype featuring a mucoid morphology, an active Type III Secretion System (T3SS, hallmark of acute infections, and no Type VI Secretion System (H1-T6SS. This virulence profile is due to a 426 bp deletion in the 3' end of the gacS gene encoding an essential regulatory protein. The absence of GacS disturbs the Gac/Rsm pathway leading to depletion of the small regulatory RNAs RsmY/RsmZ and, in consequence, to expression of T3SS, while switching off the expression of H1-T6SS and Pel polysaccharides. The CHA isolate also exhibits full ability to swim and twitch, due to active flagellum and Type IVa pili. Thus, unlike the classical scheme of balance between virulence factors, clinical strains may adapt to a local niche by expressing both alginate exopolysaccharide, a hallmark of membrane stress that protects from antibiotic action, host defences and phagocytosis, and efficient T3S machinery that is considered as an aggressive virulence factor.

Effect of apatite formation of biphasic calcium phosphate ceramic (BCP) on osteoblastogenesis using simulated body fluid (SBF) with or without bovine serum albumin (BSA)

Energy Technology Data Exchange (ETDEWEB)

Huang, Li [Guangxi Key Laboratory of Regenerative Medicine, Guangxi Medical University, Nanning (China); Department of Orthopaedic Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning (China); Zhou, Bo; Wu, Huayu [Department of Cell Biology & Genetics, School of Premedical Sciences, Guangxi Medical University, Nanning (China); Zheng, Li, E-mail: zhengli224@163.com [Guangxi Key Laboratory of Regenerative Medicine, Guangxi Medical University, Nanning (China); The Medical and Scientific Research Center, Guangxi Medical University, Nanning (China); Zhao, Jinmin, E-mail: zhaojinmin@126.com [Guangxi Key Laboratory of Regenerative Medicine, Guangxi Medical University, Nanning (China); Department of Orthopaedic Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning (China); Guangxi Colleges and Universities Key Laboratory of Regenerative Medicine, Guangxi Medical University, Nanning (China)

2017-01-01

Although biphasic calcium phosphate ceramic (BCP) holds promise in therapy of bone defect, surface mineralization prior to implantation may improve the bioactivity to better integrate with the host. Immersion in simulated body fluid (SBF) and bovine serum albumin-simulated body fluid (BSA-SBF) are common methods to form apatite interface layer. This study was intended to investigate the effect of SBF and BSA-SBF treatment on the bioactivity of BCP in vitro. In this study, osteoblasts were grown on BCP with or without treatment of SBF or BSA-SBF, and detected with general observation, scanning electron microscope (SEM), cell proliferation assay, morphology observation, viability assay, alkaline phosphatase (ALP) activity assay, and osteogenic specific gene expression of alkaline phosphatase (ALPL), bone gamma-carboxyglutamate (gla) protein (BGLAP), bone morphogenetic protein 2 (BMP2), bone sialoprotein (BSP), type I collagen (COLI) and runt-related transcription factor 2 (RUNX2) after culture of 2, 5 and 8 days. As the results shown, BCP pre-incubated in SBF and BSA-SBF up-regulated ALP activity and osteogenic related genes and proteins, which testified the positive effect of SBF and BSA-SBF. Especially, BSA-SBF enhanced the cell growth significantly. This study indicated that treatment by BSA-SBF is of importance for BCP before clinical application. - Highlights: • BCP pre-incubated in SBF and BSA-SBF significantly promoted osteogenic differetiation of osteoblasts. • BSA-SBF enhanced the cell growth more significantly than SBF. • SBF may be a little toxic to osteoblasts.

U-Pb Data On Apatites With Common Lead Correction : Exemples From The Scottish Caledonides

Science.gov (United States)

Jewison, E.; Deloule, E.; Villeneuve, J.; Bellahsen, N.; Labrousse, L.; Rosenberg, C.; Pik, R.; Chew, D.

2017-12-01

Apatite is a widely used mineral in low-temperature thermochronology (U-Th/He and AFT). The use of apatite in U-Pb geochronology has a great potential, given its closure temperature around 450°C, for orogen thermostructural evolution studies. However, since apatite can accumulate significant amount of initial Pb in its structure, its use can be hindered by the lack of 204 Pb estimations. To work around this, two options are commonly used : either use a ploting sytem that does not require corrected ratios, or use a proxy to estimate 204Pb and use it to correct the ratios. In this study we use a SIMS to mesure 204Pb in order to compare Tera-Wasserburg diagram and corrected ages to examine the cooling pattern in the northern Highlands of Scotland. The Highlands is an extensively studied caledonian collision wedge which results from the closure of the Iapétus Ocean during the Orodivician-Silurian. Two orogenic events are related to this closing, the grampian event (480-460Ma) and the scandian event (435-415 Ma) that culminated in the stacking of major ductile thrusts. The thermal history of thoses nappes are hence complex and the cooling pattern poorly constrained. Corrected apatite U-Pb ages provide new constrains on ductile wedge building and improve our understanding of mid to lower-crustal deformation and orogenic exhumation. Thoses corrected ages yield equivalent errors and mean ages from the classic method. Those data suggest a global cooling younger than previously thought and a sequence departing from a simple forward sequence. We thus present a refined thermal evolution and conceptualize a model of ductile wedge evolution.

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.

Age of hydrothermal processes in the central iberian zone (Spain according TO U-Pb dating of cassiterite and apatite

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Н. Г. Ризванова

2017-06-01

Full Text Available Results of isotope-geochemical studies by PbLS step-leaching method of cassiterite from greisens located in Logrosán granite massif (Central Iberian Zone, Spain and apatite from hydrothermal quartz-apatite vein on its exocontact indicate that in both cases a hydrothermal event is recorded in the interval of 114-126 Ma, which has been accompanied by lead supply. Within the limits of estimation error, the same age around 120 Ma corresponds to crystallization of hydrothermal apatite, formation of sticks and micro-inclusions in cassiterite from greisens and is suggested for Au-As-Sb-Pb ore mineralization, which calls for further confirmation. Xenogenous zircon from quartz-apatite vein does not react to this relatively low-temperature hydrothermal event either with building up new generations (sticks, areas of recrystallization or with rebalancing of U-Pb isotope system. The age of greisen formation has been confirmed to be around 305 Ma by PbLS method on final phases of cassiterite leaching. Earlier it was estimated with 40Ar/39Ar method on muscovite.

CHA2DS2-VASc score and risk of thromboembolism and bleeding in patients with atrial fibrillation and recent cancer

DEFF Research Database (Denmark)

D'Souza, Maria; Carlson, Nicholas; Fosbøl, Emil

2018-01-01

Background Cancer may influence the risk of thromboembolism and bleeding associated with the CHA2DS2-VASc score. We examined the risk of thromboembolism and bleeding associated with the CHA2DS2-VASc score in atrial fibrillation patients with and without recent cancer. Methods and results Using...... nationwide registers all patients diagnosed with atrial fibrillation from 2000 to 2015 and not on oral anticoagulation or heparin therapy were included and followed for 2 years. Recent cancer was defined by a cancer diagnosis 5 years or fewer earlier. Risks of thromboembolism and bleeding were estimated...... in cumulative incidence curves and Cox regression models. We included 122,053 patients with incident atrial fibrillation, 12,014 (10%) had recent cancer. The 2-year cumulative incidence of thromboembolism and bleeding in patients with versus without recent cancer was 1.7% (95% confidence interval (CI) 0...

Three dimensional printing of calcium sulfate and mesoporous bioactive glass scaffolds for improving bone regeneration in vitro and in vivo

Science.gov (United States)

Qi, Xin; Pei, Peng; Zhu, Min; Du, Xiaoyu; Xin, Chen; Zhao, Shichang; Li, Xiaolin; Zhu, Yufang

2017-02-01

In the clinic, bone defects resulting from infections, trauma, surgical resection and genetic malformations remain a significant challenge. In the field of bone tissue engineering, three-dimensional (3D) scaffolds are promising for the treatment of bone defects. In this study, calcium sulfate hydrate (CSH)/mesoporous bioactive glass (MBG) scaffolds were successfully fabricated using a 3D printing technique, which had a regular and uniform square macroporous structure, high porosity and excellent apatite mineralization ability. Human bone marrow-derived mesenchymal stem cells (hBMSCs) were cultured on scaffolds to evaluate hBMSC attachment, proliferation and osteogenesis-related gene expression. Critical-sized rat calvarial defects were applied to investigate the effect of CSH/MBG scaffolds on bone regeneration in vivo. The in vitro results showed that CSH/MBG scaffolds stimulated the adhesion, proliferation, alkaline phosphatase (ALP) activity and osteogenesis-related gene expression of hBMSCs. In vivo results showed that CSH/MBG scaffolds could significantly enhance new bone formation in calvarial defects compared to CSH scaffolds. Thus 3D printed CSH/MBG scaffolds would be promising candidates for promoting bone regeneration.

Osteoimmunology: Influence of the Immune System on Bone Regeneration and Consumption.

Science.gov (United States)

Limmer, Andreas; Wirtz, Dieter C

2017-06-01

Background Stimulating bone regeneration is a central aim in orthopaedic and trauma surgery. Although the replacement of bone with artificial materials like cement or apatite helps to keep up bone stability, new bone often cannot be regenerated. Increasing research efforts have led to the clinical application of growth factors stimulating bone growth (e.g. bone morphogenic protein, BMP) and inhibitors preventing bone consumption (e.g. RANKL blocking antibodies). These factors mostly concentrate on stimulating osteoblast or preventing osteoclast activity. Current Situation It is widely accepted that osteoblasts and osteoclasts are central players in bone regeneration. This concept assumes that osteoblasts are responsible for bone growth while osteoclasts cause bone consumption by secreting matrix-degrading enzymes such as cathepsin K and matrix metalloproteinases (MMP). However, according to new research results, bone growth or consumption are not regulated by single cell types. It is rather the interaction of various cell types that regulates bone metabolism. While factors secreted by osteoblasts are essential for osteoclast differentiation and activation, factors secreted by activated osteoclasts are essential for osteoblast activity. In addition, recent research results imply that the influence of the immune system on bone metabolism has long been neglected. Factors secreted by macrophages or T cells strongly influence bone growth or degradation, depending on the bone microenvironment. Infections, sterile inflammation or tumour metastases not only affect bone cells directly, but also influence immune cells such as T cells indirectly. Furthermore, immune cells and bone are mechanistically regulated by similar factors such as cytokines, chemokines and transcription factors, suggesting that the definition of bone and immune cells has to be thought over. Outlook Bone and the immune system are regulated by similar mechanisms. These newly identified similarities

Quantum-mechanical calculations of the electronic structure of calcium and cadmium vanadate apatites

International Nuclear Information System (INIS)

Karbovskij, V.L.; Soroka, A.P.; Kasiyanenko, V.Kh.; Shpak, A.P.

2011-01-01

Electronic structures of compounds Me 10 (VO 4 ) 6 X 2 , where Me = Ca or Cd and X = F, Cl, OH are investigated using the full potential APW + lo method. The degrees of distortions of VO 4- tetrahedra with respect to the Td point group are analyzed using a relaxation of atomic positions. Apatites in the form of Ca 10 (VO 4 ) 6 X 2 , where X = F, Cl, OH, are established to decrease the band gap by 0.5-1.0 eV under the isomorphic substitution of calcium for cadmium. Apatites Ca 10 (VO 4 ) 6 X 2 , where X = F, Cl, OH are proven to decrease the degree of covalency of the oxygen-halogen bond under the isomorphic substitution of calcium for cadmium.

Development and functioning of microorganisms in concentration cycles of sulfide copper-nickel and non-sulfide apatite-nepheline ores

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Fokina N. V.

2017-03-01

Full Text Available The number and trophic diversity of bacteria in flotation samples of apatite-nepheline and sulfide copper-nickel ores at the concentration plants of JSC "Apatite" and Kola Mining and Metallurgical Company have been determined. The study of the size and diversity of the microbiota has been conducted by culture on selective nutrient media. The total number and biomass of bacteria have been considered by fluorescence microscopy using Cyclopore polycarbonate membrane filters. Bacteria have been identified by molecular genetic methods. The least amount of both saprotrophic and other trophic groups of bacteria has been observed in the samples of ore and recycled water as at the concentrating factory of Apatit JSC, and also at the plant "Pechenganikel". It has been found out that the bacteria contained in the ore and recycling water flowing from the tailings increased their number during the flotation process due to coming of the nutrients with the flotation reagents, aeration and increased temperature. Strains which occurrence is more than 60 % have been extracted from recycled water and basic flotation products and classified as Pseudomonas. Two strains with occurrence of more than 60 % have been discovered at Apatit JSC and classified as Stenotrophomonas and Acinetobacter. The number of fungi in the cycle of apatite-nepheline ore enrichment at the factories is very low (1 to 24 CFU / 1 ml or 1 g of ore. Fungi of the genus Penicillium have been dominated, fungi of the genera Acremonium, Aureobasidium, Alternaria, Chaetomium have also been detected. At the plant "Pechenganikel" species Aspergillus fumigatus, Penicillium aurantiogriseum and P. glabrum have been extracted. It has been shown that the bacteria deteriorate the apatite flotation as a result of their interaction with active centers of calcium-containing minerals and intensive flocculation decreasing the floatation selectivity. Also some trend of copper and nickel recovery change has been

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, Øremediation technique at polluted sites. Copyright © 2011 Elsevier B.V. All rights reserved.

Crystal Structure Studies of Human Dental Apatite as a Function of Age

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Th. Leventouri

2009-01-01

Full Text Available Studies of the average crystal structure properties of human dental apatite as a function of age in the range of 5–87 years are reported. The crystallinity of the dental hydroxyapatite decreases with the age. The a-lattice constant that is associated with the carbonate content in carbonate apatite decreases with age in a systematic way, whereas the c-lattice constant does not change significantly. Thermogravimetric measurements demonstrate an increase of the carbonate content with the age. FTIR spectroscopy reveals both B and A-type carbonate substitutions with the B-type greater than the A-type substitution by a factor up to ~5. An increase of the carbonate content as a function of age can be deduced from the ratio of the 2CO3 to the 1PO4 IR modes.

The Value of CHA2DS2VASC Score in Predicting All-Cause Mortality in Patients with ST-Segment Elevation Myocardial Infarction Who Have Undergone Primary Percutaneous Coronary Intervention.

Science.gov (United States)

Keskin, Kudret; Sezai Yıldız, Süleyman; Çetinkal, Gökhan; Aksan, Gökhan; Kilci, Hakan; Çetin, Şükrü; Sığırcı, Serhat; Kılıçkesmez, Kadriye

2017-11-01

Acute coronary syndrome is the most common cause of cardiac morbidity and death. Various scoring systems have been developed in order to identify patients who are at risk for adverse outcome and may benefit from more aggressive and effective therapies. This study was designed to evaluate the CHA 2 DS 2 VASC score as a predictor of mortality inpatients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention (p-PCI). We evaluated 300 patients diagnosed with ST-elevation myocardial infarction who underwent p-PCI and calculated their CHA 2 DS 2 VASC scores. According to their CHA 2 DS 2 VASC scores, patients were divided into three groups. Group 1: 0-1 points (n = 101), Group 2: 2-3 points (n = 129), and Group 3: 4-9 points (n = 70). The mean, median and minimum duration of follow-up were 21.7 ± 9.4, 21, and 12 months, respectively. All-cause mortality was defined as the primary endpoint of the study. All-cause mortality was 4% in Group 1, 8.5% in Group 2 and 27.1% in Group 3 respectively. Kaplan-Meier analysis showed that Group 3 (CHA 2 DS 2 VASC ≥ 4) had a significantly higher incidence of death [p (log-rank) < 0.001]. In ROC analysis, AUC values for in hospital, 12-month and long-term mortality were 0.88 (0.77-0.99 95% CI), 0.82 (0.73-0.92 95% CI) and 0.79 (0.69-0.88 95% CI), respectively. CHA 2 DS 2 VASC score can be used for predicting both in-hospital, 12-month and long-term mortality in patients with STEMI who have undergone p-PCI.

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.

Novel synthesis and characterization of an AB-type carbonate-substituted hydroxyapatite.

Science.gov (United States)

Gibson, Iain R; Bonfield, William

2002-03-15

A novel synthesis route has been developed to produce a high-purity mixed AB-type carbonate-substituted hydroxyapatite (CHA) with a carbonate content that is comparable to the type and level observed in bone mineral. This method involves the aqueous precipitation in the presence of carbonate ions in solution of a calcium phosphate apatite with a Ca/P molar ratio greater than the stoichiometric value of 1.67 for hydroxyapatite (HA). The resulting calcium-rich carbonate-apatite is sintered/heat-treated in a carbon dioxide atmosphere to produce a single-phase, crystalline carbonate-substituted hydroxyapatite. In contrast to previous methods for producing B- or AB-type carbonate-substituted hydroxyapatites, no sodium or ammonium ions, which would be present in the reaction mixture from the sodium or ammonium carbonates commonly used as a source of carbonate ions, were present in the final product. The chemical and phase compositions of the carbonate-substituted hydroxyapatite was characterized by X-ray fluorescence and X-ray diffraction, respectively, and the level and nature of the carbonate substitution were studied using C-H-N analysis and Fourier transform infrared spectroscopy, respectively. The carbonate substitution improves the densification of hydroxyapatite and reduces the sintering temperature required to achieve near-full density by approximately 200 degrees C compared to stoichiometric HA. Initial studies have shown that these carbonate-substituted hydroxyapatites have improved mechanical and biologic properties compared to stoichiometric hydroxyapatite. Copyright 2001 John Wiley & Sons, Inc. J Biomed Mater Res 59: 697-708, 2002

Apatite formability of boron nitride nanotubes

International Nuclear Information System (INIS)

Lahiri, Debrupa; Keshri, Anup K; Agarwal, Arvind; Singh, Virendra; Seal, Sudipta

2011-01-01

This study investigates the ability of boron nitride nanotubes (BNNTs) to induce apatite formation in a simulated body fluid environment for a period of 7, 14 and 28 days. BNNTs, when soaked in the simulated body fluid, are found to induce hydroxyapatite (HA) precipitation on their surface. The precipitation process has an initial incubation period of ∼ 4.6 days. The amount of HA precipitate increases gradually with the soaking time. High resolution TEM results indicated a hexagonal crystal structure of HA needles. No specific crystallographic orientation relationship is observed between BNNT and HA, which is due to the presence of a thin amorphous HA layer on the BNNT surface that disturbs a definite orientation relationship.

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.

Effect of calcium carbonate on hardening, physicochemical properties, and in vitro degradation of injectable calcium phosphate cements.

NARCIS (Netherlands)

Sariibrahimoglu, K.; Leeuwenburgh, S.C.G.; Wolke, J.G.C.; Yubao, L.; Jansen, J.A.

2012-01-01

The main disadvantage of apatitic calcium phosphate cements (CPCs) is their slow degradation rate, which limits complete bone regeneration. Carbonate (CO(3)(2)(-)) is the common constituent of bone and it can be used to improve the degradability of the apatitic calcium phosphate ceramics. This study

Field trial using bone meal amendments to remediate mine waste derived soil contaminated with zinc, lead and cadmium

International Nuclear Information System (INIS)

Sneddon, I.R.; Orueetxebarria, M.; Hodson, M.E.; Schofield, P.F.; Valsami-Jones, E.

2008-01-01

Bone meal amendments are being considered as a remediation method for metal-contaminated wastes. In various forms (biogenic, geogenic or synthetic), apatite, the principal mineral constituent of bone, has shown promise as an amendment to remediate metal-contaminated soils via the formation of insoluble phosphates of Pb and possibly other metals. The efficacy of commercially available bovine bone meal in this role was investigated in a field trial at Nenthead, Cumbria with a mine waste derived soil contaminated with Zn, Pb and Cd. Two 5 m 2 plots were set up; the first as a control and the second, a treatment plot where the soil was thoroughly mixed with bone meal to a depth of 50 cm at a soil to amendment ratio of 25:1 by weight. An array of soil solution samplers (Rhizon SMS TM ) were installed in both plots and the soil pore water was collected and analysed for Ca, Cd, Zn and Pb regularly over a period of 2 a. Concurrently with the field trial, a laboratory trial with 800 mm high and 100 mm wide leaching columns was conducted using identical samplers and with soil from the field site. A substantial release of Zn, Pb, Cd and Ca was observed associated with the bone meal treatment. This release was transient in the case of the leaching columns, and showed seasonal variation in the case of the field trial. It is proposed that this effect resulted from metal complexation with organic acids released during breakdown of the bone meal organic fraction and was facilitated by the relatively high soil pH of 7.6-8.0. Even after this transient release effect had subsided or when incinerated bone meal was substituted in order to eliminate the organic fraction, no detectable decrease in dissolved metals was observed and no P was detected in solution, in contrast with an earlier small column laboratory study. It is concluded that due to the relative insolubility of apatite at above-neutral pH, the rate of supply of phosphate to soil solution was insufficient to result in

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

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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.

Nano-beta-tricalcium phosphates synthesis and biodegradation: 2. Biodegradation and apatite layer formation on nano-{beta}-TCP synthesized via microwave treatment

Energy Technology Data Exchange (ETDEWEB)

Abdel-Fattah, Wafa I; Elkhooly, Tarek A, E-mail: nrcfifi@yahoo.co [Department of Biomaterials, National Research Center, Cairo (Egypt)

2010-06-01

The degradation and/or apatite layer precipitation ability of porous {beta}-tricalcium phosphate ({beta}-TCP) samples treated and untreated with microwave radiation during synthesis is investigated. Microwave heating was used to accelerate the formation of CDHA with the Ca/P ratio 1.5 in a shorter processing time which later forms {beta}-TCP at around 650 {sup 0}C. Soaking in simulated body fluid (SBF) for several periods (4, 8, 12, 24, 36, 48, 60 and 72 h) is performed in a cumulative manner. The deposition of an apatite layer is followed through diffuse reflected FT-IR, SEM and EDS. A microwave-treated sample having a smaller particle size than its parent induces the formation of a homogeneous carbonated apatite layer on its surface. On the other hand, the parent {beta}-TCP sample exhibited less ability to induce Ca-P formation after being soaked in SBF. The formation of an apatite layer is attributed to the increase in surface area consequent to reduced particle and grain sizes besides the presence of a minor amount of hydroxyapatite phase in the microwave-treated {beta}-TCP sample. The results prove that it is possible to control the biodegradation and apatite layer formation on sintered {beta}-TCP porous disks through controlling the particle size.

Effect of white mineral trioxide aggregate compared with biomimetic carbonated apatite on dentine bridge formation and inflammatory response in a dental pulp model.

Science.gov (United States)

Danesh, F; Vahid, A; Jahanbani, J; Mashhadiabbas, F; Arman, E

2012-01-01

  To evaluate the effects of apatite precipitation on the biocompatibility and hard tissue induction properties of white mineral trioxide aggregate (WMTA) in a dental pulp model.   Pulp exposures were created on the axial walls of 32 sound canine teeth of eight dogs. Four additional sound teeth served as controls. The pulps were capped either with WMTA or apatite derivatives [biomimetic carbonated apatite (BCAp)] in the interaction of WMTA with a synthetic tissue fluid and restored with zinc oxide-eugenol cement. After 7 and 70 days, the animals were killed, and the histological specimens taken from the teeth were stained with haematoxylin and eosin for histomorphological evaluation. The Brown and Brenn technique was employed to stain bacteria. The data were subjected to nonparametric Kruskall-Wallis analysis and Mann-Whitney U_tests.   Biomimetic carbonated apatite did not induce hard tissue bridge formation. WMTA performed significantly better than BCAp in this respect at both periods (P 0.05).   White mineral trioxide aggregate induced hard tissue formation via a mechanism other than that postulated via apatite formation. © 2011 International Endodontic Journal.

Apatite intergrowths in clinopyroxene megacrysts from the Ostrzyca Proboszczowicka (SW Poland) basanite

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Lipa, Danuta; Puziewicz, Jacek; Ntaflos, Theodoros; Matusiak-Małek, Magdalena

2015-04-01

The Cenozoic basanite from the Ostrzyca Proboszczowicka in Lower Silesia (SW Poland) belongs to numerous lavas occurring in the NE part of the Central European Volcanic Province. Basanite contains clinopyroxene megacrysts up to 3 cm in size. The clinopyroxene has the composition of aluminian-sodian diopside (mg# 0.61-0.70, 0.08-0.12 atoms Na pfu and 0.88-0.93 atoms Ca pfu). Cr is absent. The REE contents are above the primitive mantle reaching up to 18 x PM at Nd. Primitive-mantle normalized REE patterns show enrichment in LREE relative to HREE (LaN/LuN=3.81-5.01). The REE patterns of all the megacrysts show deflection in La-Nd. The trace element patterns are characterized by positive Zr, Hf and in some cases also Ta anomalies, and negative U, La, Sr, Ti and Pb ones. In some samples strong depletion (down to 0.01 x PM) in Rb and Ba is observed.The Ostrzyca megacrysts formed cumulate, which crystallized from magma similar to the host basanite, but more fractionated and enriched in REE, particularly in LREE (Lipa et al., 2014). This happened at mid-crustal depths (10-15 km) and the new pulse of basanitic magma entrained the crystals forming the non-solidified cumulate and brought them to the surface (Lipa et al., 2014). Clinopyroxene megacrysts contain large, transparent, euhedral apatite crystals up to 7 mm. The major element composition indicates the fluor-apatite with F content ranging from 0.87 to 1.93 wt.%. Chlorine content is strongly variable between grains (0.05-1.75 wt.%). Apatite is strongly enriched in LREE relative to HREE (LaN/LuN=60.39-62.23, about 1000 x PM for LREE and about 10 x PM for HREE). The REE patterns are nearly linear, with slight positive Nd and Gd anomalies. The trace element patterns are characterized by very strong negative anomalies of HFSE (Nb, Ta, Zr, Hf, Ti) and Pb, and weaker negative Sr anomaly. Concentration of Yb and Lu is on the level 10 x PM, whereas Rb, Hf and Ti are depleted relative to PM. Apatite preceded clinopyroxene

The influence of channel anion identity on the high-pressure crystal structure, compressibility, and stability of apatite

Science.gov (United States)

Skelton, Richard; Walker, Andrew M.

2018-03-01

The material properties of the common phosphate mineral apatite are influenced by the identity of the channel anion, which is usually F-, Cl-, or (OH)-. Density functional theory calculations have been used to determine the effect of channel anion identity on the compressibility and structure of apatite. Hydroxyapatite and fluorapatite are found to have similar zero pressure bulk moduli, of 79.2 and 82.1 GPa, respectively, while chlorapatite is considerably more compressible, with K 0 = 55.0 GPa. While the space groups of hydroxyapatite and fluorapatite do not change between 0 and 25 GPa, symmetrization of the Cl- site in chlorapatite at 7.5 GPa causes the space group to change from P2 1 /b to P6 3 /m. Examination of the valence electron density distribution in chlorapatite reveals that this symmetry change is associated with a change in the coordination of the Cl- anion from threefold to sixfold coordinated by Ca. We also calculate the pressure at which apatite decomposes to form tuite, a calcium orthophosphate mineral, and find that the transition pressure is sensitive to the identity of the channel anion, being lowest for fluorapatite (13.8 GPa) and highest for chlorapatite (26.9 GPa). Calculations are also performed within the DFT-D2 framework to investigate the influence of dispersion forces on the compressibility of apatite minerals.

The efficacy of hydrothermally obtained carbonated hydroxyapatite in healing alveolar bone defects in rats with or without corticosteroid treatment

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Marković Dejan

2014-01-01

Full Text Available Background/Aim. Autogenous bone grafting has been the gold standard in clinical cases when bone grafts are required for bone defects in dentistry. The study was undertaken to evaluate multilevel designed carbonated hydroxyapatite (CHA obtained by hydrothermal method, as a bone substitute in healing bone defects with or without corticosteroid treatment in rats as assessed by histopathologic methods. Methods. Bone defects were created in the alveolar bone by teeth extraction in 12 rats. The animals were initially divided into two groups. The experimental group was pretreated with corticosteroids: methylprednisolone and dexamethasone, intramuscularly, while the control group was without therapy. Posterior teeth extraction had been performed after the corticosteroid therapy. The extraction defects were fulfilled with hydroxyapatite with bimodal particle sizes in the range of 50-250 μm and the sample from postextocactional defect of the alveolar bone was analyzed pathohystologically. Results. The histopatological investigations confirmed the biologic properties of the applied material. The evident growth of new bone in the alveolar ridge was clearly noticed in both groups of rats. Carbonated HA obtained by hydrothermal method promoted bone formation in the preformed defects, confirming its efficacy for usage in bone defects. Complete resorption of the material’s particles took place after 25 weeks. Conclusion. Hydroxyapatite completely meets the clinical requirements for a bone substitute material. Due to its microstructure, complete resorption took place during the observation period of the study. Corticosteroid treatment did not significantly affect new bone formation in the region of postextractional defects. [Projekat Ministarstva nauke Republike Srbije, br. 172026

High-speed photometry of the dwarf nova Z Cha in quiescence

International Nuclear Information System (INIS)

Wood, Janet; Horne, Keith; Berriman, Graham; O'Donoghue, Darragh; Warner, Brian

1986-01-01

High-speed white light photometry of the cataclysmic variable star Z Cha is used to study the structure of the system and to derive the properties of its components. The white dwarf and bright spot eclipse timings require a mass ratio, q=Msub(R)/Msub(WD) of 0.146 0 .9>i>81 0 .6. The infalling stream passes through the light centre of the bright spot. If the central luminous object is the white dwarf its mass is 0.54+-0.01 Msolar mass which corresponds to a secondary star mass of 0.081+-0.003 Msolar mass. Agreement between colour and brightness temperatures for the white dwarf and bright spot provide a rough confirmation of the 97 pc distance. (author)

Chitosan(PEO)/silica hybrid nanofibers as a potential biomaterial for bone regeneration.

Science.gov (United States)

Toskas, Georgios; Cherif, Chokri; Hund, Rolf-Dieter; Laourine, Ezzeddine; Mahltig, Boris; Fahmi, Amir; Heinemann, Christiane; Hanke, Thomas

2013-05-15

New hybrid nanofibers prepared with chitosan (CTS), containing a total amount of polyethylene oxide (PEO) down to 3.6wt.%, and silica precursors were produced by electrospinning. The solution of modified sol-gel particles contained tetraethoxysilane (TEOS) and the organosilane 3-glycidyloxypropyltriethoxysilane (GPTEOS). This is rending stable solution toward gelation and contributing in covalent bonding with chitosan. The fibers encompass advantages of biocompatible polymer template silicate components to form self-assembled core-shell structure of the polymer CTS/PEO encapsulated by the silica. Potential applicability of this hybrid material to bone tissue engineering was studied examining its cellular compatibility and bioactivity. The nanofiber matrices were proved cytocompatible when seeded with bone-forming 7F2-cells, promoting attachment and proliferation over 7 days. These found to enhance a fast apatite formation by incorporation of Ca(2+) ions and subsequent immersion in modified simulated body fluid (m-SBF). The tunable properties of these hybrid nanofibers can find applications as active biomaterials in bone repair and regeneration. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

A combined PIXE-PIGE approach for the assessment of the diagenetic state of cremated bones submitted to AMS radiocarbon dating

Energy Technology Data Exchange (ETDEWEB)

Quarta, Gianluca, E-mail: gianluca.quarta@unisalento.it [CEDAD-Department of Engineering for Innovation, University of Salento, via per Monteroni, 73100 Lecce (Italy); Calcagnile, Lucio; D' Elia, Marisa; Maruccio, Lucio; Gaballo, Valentina; Caramia, Annalisa [CEDAD-Department of Engineering for Innovation, University of Salento, via per Monteroni, 73100 Lecce (Italy)

2013-01-15

Bone samples from a Bronze age necropolis in Northern Italy, exposed to different combustion temperatures, were submitted to XRD (X-ray Diffraction), PIXE (Particle Induced X-ray Emission) and PIGE (Particle Induced Gamma Ray Emission) analyses in order to obtain information about their diagenetic state. Structural carbonate was then extracted by acid hydrolysis and used for {sup 14}C-AMS (Accelerator Mass Spectrometry) dating. These analytical techniques permitted the study of the effects of the combustion temperature on the crystallinity of the bone apatite and on its elemental chemical composition in terms of major, minor and trace elements. The results indicate that combustion at temperatures above {approx}700 Degree-Sign C induces changes in the bone crystalline structure, reducing the diagenetic uptake of elements from the burial environment.

Carbonate loss from two magnesium-substituted carbonated apatites prepared by different synthesis techniques

International Nuclear Information System (INIS)

Barinov, S.M.; Rau, J.V.; Fadeeva, I.V.; Cesaro, S. Nunziante; Ferro, D.; Trionfetti, G.; Komlev, V.S.; Bibikov, V.Yu.

2006-01-01

This study was aimed at the investigation of the thermal stability of Mg-substituted carbonated apatites over the wide temperature range. Two different apatites were studied, which were prepared by either precipitation from aqueous solution or by solid-liquid interaction. The following methods were employed: FTIR spectroscopy of the condensed gas phase to evaluate the CO and CO 2 release with increasing temperature, FTIR of the solid residue after heating, XRD analysis, thermogravimetry and scanning electron microscopy. Decomposition behavior was shown to depend significantly on the synthesis method. Wet-synthesized powders are significantly less thermally stable compared with those prepared by solid-liquid interaction. Intensive release of carbon oxides from the former was observed at 300 deg. C, whereas the latter powder was relatively stable up to temperature about 1000 deg. C

Mineralization behavior and interface properties of BG-PVA/bone composite implants in simulated body fluid

Energy Technology Data Exchange (ETDEWEB)

Ma Yanxuan; Zheng Yudong; Huang Xiaoshan; Xi Tingfei; Han Dongfei [School of Materials Science and Engineering, Beijing University of Science and Technology, Beijing 100083 (China); Lin Xiaodan [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Song Wenhui, E-mail: zhengyudong@mater.ustb.edu.c, E-mail: wenhui.song@brunel.ac.u [Wolfson Center for Materials Processing, School of Engineering and Design, Brunel University, West London, UB8 3PH (United Kingdom)

2010-04-15

Due to the non-bioactivity and poor conjunction performance of present cartilage prostheses, the main work here is to develop the bioactive glass-polyvinyl alcohol hydrogel articular cartilage/bone (BG-PVA/bone) composite implants. The essential criterion for a biomaterial to bond with living bone is well-matched mechanical properties as well as biocompatibility and bioactivity. In vitro studies on the formation of a surface layer of carbonate hydroxyl apatite (HCA) and the corresponding variation of the properties of biomaterials are imperative for their clinical application. In this paper, the mineralization behavior and variation of the interface properties of BG-PVA/bone composites were studied in vitro by using simulated body fluid (SBF). The mineralization and HCA layer formed on the interface between the BG-PVA hydrogel and bone in SBF could provide the composites with bioactivity and firmer combination. The compression property, shear strength and interface morphology of BG-PVA/bone composite implants varying with the immersion time in SBF were characterized. Also, the influence laws of the immersion time, content of BG in the composites and aperture of bones to the mineralization behavior and interface properties were investigated. The good mineralization behavior and enhanced conjunction performance of BG-PVA/bone composites demonstrated that this kind of composite implant might be more appropriate cartilage replacements.

Mineralization behavior and interface properties of BG-PVA/bone composite implants in simulated body fluid.

Science.gov (United States)

Ma, Yanxuan; Zheng, Yudong; Huang, Xiaoshan; Xi, Tingfei; Lin, Xiaodan; Han, Dongfei; Song, Wenhui

2010-04-01

Due to the non-bioactivity and poor conjunction performance of present cartilage prostheses, the main work here is to develop the bioactive glass-polyvinyl alcohol hydrogel articular cartilage/bone (BG-PVA/bone) composite implants. The essential criterion for a biomaterial to bond with living bone is well-matched mechanical properties as well as biocompatibility and bioactivity. In vitro studies on the formation of a surface layer of carbonate hydroxyl apatite (HCA) and the corresponding variation of the properties of biomaterials are imperative for their clinical application. In this paper, the mineralization behavior and variation of the interface properties of BG-PVA/bone composites were studied in vitro by using simulated body fluid (SBF). The mineralization and HCA layer formed on the interface between the BG-PVA hydrogel and bone in SBF could provide the composites with bioactivity and firmer combination. The compression property, shear strength and interface morphology of BG-PVA/bone composite implants varying with the immersion time in SBF were characterized. Also, the influence laws of the immersion time, content of BG in the composites and aperture of bones to the mineralization behavior and interface properties were investigated. The good mineralization behavior and enhanced conjunction performance of BG-PVA/bone composites demonstrated that this kind of composite implant might be more appropriate cartilage replacements.

Hydroxyapatite/polylactide biphasic combination scaffold loaded with dexamethasone for bone regeneration.

Science.gov (United States)

Son, Jun-Sik; Kim, Su-Gwan; Oh, Ji-Su; Appleford, Mark; Oh, Sunho; Ong, Joo L; Lee, Kyu-Bok

2011-12-15

This study presents a novel design of a ceramic/polymer biphasic combination scaffold that mimics natural bone structures and is used as a bone graft substitute. To mimic the natural bone structures, the outside cortical-like shells were composed of porous hydroxyapatite (HA) with a hollow interior using a polymeric template-coating technique; the inner trabecular-like core consisted of porous poly(D,L-lactic acid) (PLA) that was loaded with dexamethasone (DEX) and was directly produced using a particle leaching/gas forming technique to create the inner diameter of the HA scaffold. It was observed that the HA and PLA parts of the fabricated HA/PLA biphasic scaffold contained open and interconnected pore structures, and the boundary between both parts was tightly connected without any gaps. It was found that the structure of the combination scaffold was analogous to that of natural bone based on micro-computed tomography analysis. Additionally, the dense, uniform apatite layer was formed on the surface of the HA/PLA biphasic scaffold through a biomimetic process, and DEX was successfully released from the PLA of the biphasic scaffold over a 1-month period. This release caused human embryonic palatal mesenchyme cells to proliferate, differentiate, produce ECM, and form tissue in vitro. Therefore, it was concluded that this functionally graded scaffold is similar to natural bone and represents a potential bone-substitute material. Copyright © 2011 Wiley Periodicals, Inc.

Relationship of CHA2DS2-VASc and CHADS2 score to left atrial remodeling detected by velocity vector imaging in patients with atrial fibrillation.

Directory of Open Access Journals (Sweden)

Yihui Li

Full Text Available BACKGROUND: The CHADS2/CHA2DS2-VASc scores are used to predict thrombo-embolic/stroke in patients with nonvalvular atrial fibrillation (AF. Nevertheless, limited data are available regarding the association between these risk stratification for stroke and left atrial (LA remodeling status of AF patients. The purpose of this study was to explore the association between these scores and LA remodeling status assessed quantificationally by echocardiography in AF patients. METHODS: One hundred AF patients were divided into 3 groups based on the CHA2DS2-VASc/CHADS2 score: the score of 0 (low stroke risk, the score of 1 (moderate stroke risk and the score of ≥2 (high stroke risk. All patients were performed through conventional and velocity vector imaging echocardiography. Echocardiographic parameters: maximum LA volume index (LAVImax, LA total emptying fraction (LAEFt and LA mean strain were obtained to assess quantificationally LA remodeling status. RESULTS: On categorizing with CHA2DS2-VASc, the score of 1 group showed augment in LAVImax and attenuation in LA mean strain derived from VVI, compared with the score of 0 group (LAVImax: 40.27±21.91 vs. 26.79±7.87, p=0.002; LA mean strain: 15.18±6.36 vs. 22±8.54, p=0.001. On categorizing with the CHADS2 score, similar trends were seen between the score of ≥2 and 1 groups (LAVImax: 43.72±13.77 vs. 31.41±9.50, p<0.001; LA mean strain: 11.01±5.31 vs. 18.63±7.00, p<0.001. With multivariate logistic regression, LAVImax (odds ratio: 0.92 , 95% C=I: 0.85 to 0.98, p= 0.01 and LA mean strain reflecting LA remodeling (odds ratio: 1.10, 95% CI: 1.02 to 1.19, p=0.01 were strongly predictive of the CHA2DS2-VASc score of 0. CONCLUSIONS: The superiority of the CHADS2 score may lay in identifying LA remodeling of AF patients with high stroke risk. Whereas, the CHA2DS2-VASc score was better than the CHADS2 score at identifying LA remodeling of AF patients presenting low stroke risk.

A Bioactive Hydrogel and 3D Printed Polycaprolactone System for Bone Tissue Engineering

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Ivan Hernandez

2017-07-01

Full Text Available In this study, a hybrid system consisting of 3D printed polycaprolactone (PCL filled with hydrogel was developed as an application for reconstruction of long bone defects, which are innately difficult to repair due to large missing segments of bone. A 3D printed gyroid scaffold of PCL allowed a larger amount of hydrogel to be loaded within the scaffolds as compared to 3D printed mesh and honeycomb scaffolds of similar volumes and strut thicknesses. The hydrogel was a mixture of alginate, gelatin, and nano-hydroxyapatite, infiltrated with human mesenchymal stem cells (hMSC to enhance the osteoconductivity and biocompatibility of the system. Adhesion and viability of hMSC in the PCL/hydrogel system confirmed its cytocompatibility. Biomineralization tests in simulated body fluid (SBF showed the nucleation and growth of apatite crystals, which confirmed the bioactivity of the PCL/hydrogel system. Moreover, dissolution studies, in SBF revealed a sustained dissolution of the hydrogel with time. Overall, the present study provides a new approach in bone tissue engineering to repair bone defects with a bioactive hybrid system consisting of a polymeric scaffold, hydrogel, and hMSC.

A Bioactive Hydrogel and 3D Printed Polycaprolactone System for Bone Tissue Engineering.

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Hernandez, Ivan; Kumar, Alok; Joddar, Binata

2017-09-01

In this study, a hybrid system consisting of 3D printed polycaprolactone (PCL) filled with hydrogel was developed as an application for reconstruction of long bone defects, which are innately difficult to repair due to large missing segments of bone. A 3D printed gyroid scaffold of PCL allowed a larger amount of hydrogel to be loaded within the scaffolds as compared to 3D printed mesh and honeycomb scaffolds of similar volumes and strut thicknesses. The hydrogel was a mixture of alginate, gelatin, and nano-hydroxyapatite, infiltrated with human mesenchymal stem cells (hMSC) to enhance the osteoconductivity and biocompatibility of the system. Adhesion and viability of hMSC in the PCL/hydrogel system confirmed its cytocompatibility. Biomineralization tests in simulated body fluid (SBF) showed the nucleation and growth of apatite crystals, which confirmed the bioactivity of the PCL/hydrogel system. Moreover, dissolution studies, in SBF revealed a sustained dissolution of the hydrogel with time. Overall, the present study provides a new approach in bone tissue engineering to repair bone defects with a bioactive hybrid system consisting of a polymeric scaffold, hydrogel, and hMSC.

The effect of secondary apatite on the initial 87Sr/86Sr ratio determination in granitic rocks: a case study of the Tadamigawa pluton, northeastern Japan

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Wakasugi, Y.; Ichino, K.; Tanioka, Y.; Wakaki, S.; Tsuboi, M.; Ishikawa, T.

2017-12-01

Apatite is a major accessory mineral in igneous rocks. Because Rb contents in apatite are very low, 87Sr/86Sr ratios of magmatic apatite are useful to estimate the initial 87Sr/86Sr ratio (SrI) of igneous rocks. Secondary post-magmatic event such as hydrothermal alteration may also crystallize secondary apatite, which may inhibit the estimation of SrI of igneous rocks. In this study, we examine the effects of secondary apatite on the initial 87Sr/86Sr ratio determination of granitic rocks by using acid leaching technique. Leached apatite samples were first separated from the whole rock powder as a heavy mineral fraction by heavy liquid technique, and the heavy mineral fraction was then leached by 3 M HNO3. The isotopic ratios of Sr and the concentrations of Rb and Sr were analyzed by TIMS and ICP-MS at Kochi Core Center, respectively. The Tadamigawa Older-stage granites, which locate in the Taishaku Mountains at the northeastern part of Japan, intrude into the Ashio Jurassic complex, and the ages of these rocks are late Cretaceous to Paleogene. The U-Pb ages of zircon and the K-Ar ages of biotite for these rocks are c. 100 Ma [1, 2]. Rb-Sr whole-rock isochron age of the pluton is 96.5 ± 1.3 Ma (SrI = 0.70534 ± 0.00003) and it is concordant with other radiometric ages. Rb-Sr mineral isochron ages range from 84.4 to 97.3 Ma and these ages are relatively younger than the Rb-Sr whole-rock isochron age. The difference among radiometric ages may reflect the difference of the closure temperature in each isotopic system. The Tadamigawa Older-stage granites have SrI for Rb-Sr mineral isochron range from 0.7053 to 0.7061 and are very similar to that (0.70534) for Rb-Sr whole-rock isochron. These may suggest that the Tadamigawa Older-stage granites are generated from same parental magma. However, 87Sr/86Sr ratios of the leached apatite samples were 0.70544-0.70856 and are relatively higher than SrI obtained from the Rb-Sr mineral isochrons (0.7053-0.7061). This result

A new hydrometallurgical process for extracting rare earths from apatite using solvent extraction with P35

International Nuclear Information System (INIS)

Li Hongfei; Guo Fuqiang; Zhang Zhifeng; Li Deqian; Wang Zhonghuai

2006-01-01

In this paper, a new process is proposed to recover rare earths from nitric acid leaching of apatite without interfering with the normal route for fertilizer production using solvent extraction with dimethyl heptyl methyl phosphonate CH 3 P(O)(OC 8 H 17 ) 2 (P 35 , B). In the present work, the leaching conditions are studied. In selected condition, apatite was dissolved in 20% (v/v) nitric acid solution at 60-70 deg. C while agitating. The most suitable acidity for extraction is 0.4 M HNO 3 . More than 98% of rare earths in apatite can be recovered using countercurrent extraction process with six stages when phase ratio = 0.5, and defluorination is unnecessary. The influences of phase ratio, stage number, acidity and salting-out agent on extractabilities of P 35 are studied. The results show that rare earths can be separated with P 35 from Ca, P, Fe and other impurities. Mixed rare earth oxides (REO) of which purity is more than 95% with yield over 98% can be obtained

Surface modification of beta-tricalcium phosphate scaffolds with topological nanoapatite coatings

International Nuclear Information System (INIS)

Zhang Faming; Chang Jiang; Lu Jianxi; Ning Congqin

2008-01-01

A biomimetic process was developed to create a modulable surface topography of nanocrystalline apatite on pure beta-tricalcium phosphate (β-TCP) scaffolds. The scaffolds were immersed in a newly revised simulated body fluid (R n -SBF) to produce nanocrystalline apatite. The obtained surfaces were investigated using scanning electric microscopy, energy dispersion spectrum, Fourier transform infrared spectroscopy, X-ray diffraction, and transmission electric microscopy. Nanoparticulates apatite were produced on the surface of the scaffolds for 1 day's soaking; increasing soaking to 3 days led to the formation of a surface covered by needle-like apatite nanocrystals; and a surface coating of needle-like apatite clusters was created after two weeks' soaking in the R n -SBF without bicarbonate ion concentrations. The increase of bicarbonate ion concentrations progressively in the R n -SBF provided a surface entirely coated with a nanostructured thick layer of apatite. These apatite nanostructures were low-crystalline bone-like apatite. The mechanisms for the apatite formation and transition of surface topographies were also discussed. Therefore, a variety of surface topography of nanoapatite coatings on the β-TCP scaffolds can be obtained using this method, which may enhance cell adhesion to the scaffolds for bone tissue engineering applications

Bone bonding bioactivity of Ti metal and Ti-Zr-Nb-Ta alloys with Ca ions incorporated on their surfaces by simple chemical and heat treatments.

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Fukuda, A; Takemoto, M; Saito, T; Fujibayashi, S; Neo, M; Yamaguchi, S; Kizuki, T; Matsushita, T; Niinomi, M; Kokubo, T; Nakamura, T

2011-03-01

Ti15Zr4Nb4Ta and Ti29Nb13Ta4.6Zr, which do not contain the potentially cytotoxic elements V and Al, represent a new generation of alloys with improved corrosion resistance, mechanical properties, and cytocompatibility. Recently it has become possible for the apatite forming ability of these alloys to be ascertained by treatment with alkali, CaCl2, heat, and water (ACaHW). In order to confirm the actual in vivo bioactivity of commercially pure titanium (cp-Ti) and these alloys after subjecting them to ACaHW treatment at different temperatures, the bone bonding strength of implants made from these materials was evaluated. The failure load between implant and bone was measured for treated and untreated plates at 4, 8, 16, and 26 weeks after implantation in rabbit tibia. The untreated implants showed almost no bonding, whereas all treated implants showed successful bonding by 4 weeks, and the failure load subsequently increased with time. This suggests that a simple and economical ACaHW treatment could successfully be used to impart bone bonding bioactivity to Ti metal and Ti-Zr-Nb-Ta alloys in vivo. In particular, implants heat treated at 700 °C exhibited significantly greater bone bonding strength, as well as augmented in vitro apatite formation, in comparison with those treated at 600 °C. Thus, with this improved bioactive treatment process these advantageous Ti-Zr-Nb-Ta alloys can serve as useful candidates for orthopedic devices. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Effect of carbonated hydroxyapatite incorporated advanced platelet rich fibrin intrasulcular injection on the alkaline phosphatase level during orthodontic relapse

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Alhasyimi, Ananto Ali; Pudyani, Pinandi Sri; Asmara, Widya; Ana, Ika Dewi

2018-02-01

Nowadays, relapse in orthodontic treatment is considered very important because of high incidence of relapse after the treatment. Alkaline phosphatase (ALP) as a biomarker of bone formation will decrease in compression sites during relapse after orthodontic tooth movement. In this situation, manipulating alveolar bone remodeling to increase ALP level is considered one of the new strategies to prevent relapse properly. In the field of tissue engineering, in this study, carbonated hydroxyapatite (CHA) is expected to have the ability to incorporate advanced platelet rich fibrin (aPRF). Next, CHA will retain the aPRF containing various growth factors (GF) until it reaches into a specific targeted area, gradually degraded, and deliver the GF in a controlled manner to prevent relapse. Here, gingival crevicular fluid (GCF) of 45 samples (n=45) were collected and levels of ALP were analyzed using UV-Vis 6300 Spectrophotometer at 405 nm wavelength. We found that there is a significant difference of ALP levels (p<0.05) in GCF between treatments and control groups. ALP level was elevated significantly in CHA and CHA-aPRF groups at days 7 and 14 after debonding compared with the control groups. The peak level of ALP was observed at days 14 after debonding in groups C (0.789 ± 0.039 U/mg). Therefore, it can be concluded that the application of hydrogel CHA with controlled release manner incorporated aPRF enhances bone regeneration by increasing ALP level.

Apatite fission track dating and thermal history of Qing-He region in Altay Mountains

International Nuclear Information System (INIS)

Bao Zengkuan; Chinese Academy of Sciences, Beijing; Yuan Wanming; Dong Jinquan; Gao Shaokai

2005-01-01

Fission track ages (FTA) and track lengths of apatite from Qing-He diorite intrusion in Altay Mountains are measured. Apatite fission track ages of three diorite samples is range from (78±5) Ma to (95 ± 5) Ma, and the lengths of horizontal confined spontaneous fission tracks are (13.2 ± 1.2)-(13.5 ±1.3) μm. The distribution of the track length is narrow and symmetrical with a mean length of approximately 13.3 μm and a standard deviation of around 0.1 μm. The inverse modeling results show that thermal history of this region has four stages, two rapid uplift of this region still existed magmatic intrusion and tectonic movements in Yanshanian. (authors)

Dispersion of uranium in accessory apatite in crystalline rocks and its possible petrogenetic meaning

International Nuclear Information System (INIS)

Kral, J.; Burchart, J.

1983-01-01

The coefficient of variation for grain-by-grain fission track uranium analysis of apatites from igneous rocks seems to reflect the temperature of crystallization and the cooling rate. For metamorphic rocks the coefficient represents a complex record of the homogeneity of the source and of metamorphic neocrystallization. As a test case 41 West Carpathian rocks have been examined and the coefficients of variation for U in apatites found to be: granitic rocks 0.30-0.79, paragneisses 0.35-0.95, migmatites 0.55-0.87, and volcanic rocks 0.30-0.40. Most of the frequency distributions are lognormal, though for some cases a normal distribution gives a better fit, and some are incompatible with either of the two distributions. (orig.)

Construction of human induced pluripotent stem cell-derived oriented bone matrix microstructure by using in vitro engineered anisotropic culture model.

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Ozasa, Ryosuke; Matsugaki, Aira; Isobe, Yoshihiro; Saku, Taro; Yun, Hui-Suk; Nakano, Takayoshi

2018-02-01

Bone tissue has anisotropic microstructure based on collagen/biological apatite orientation, which plays essential roles in the mechanical and biological functions of bone. However, obtaining an appropriate anisotropic microstructure during the bone regeneration process remains a great challenging. A powerful strategy for the control of both differentiation and structural development of newly-formed bone is required in bone tissue engineering, in order to realize functional bone tissue regeneration. In this study, we developed a novel anisotropic culture model by combining human induced pluripotent stem cells (hiPSCs) and artificially-controlled oriented collagen scaffold. The oriented collagen scaffold allowed hiPSCs-derived osteoblast alignment and further construction of anisotropic bone matrix which mimics the bone tissue microstructure. To the best of our knowledge, this is the first report showing the construction of bone mimetic anisotropic bone matrix microstructure from hiPSCs. Moreover, we demonstrated for the first time that the hiPSCs-derived osteoblasts possess a high level of intact functionality to regulate cell alignment. © 2017 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 360-369, 2018. © 2017 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc.

Development of layered anode structures supported over Apatite-type Solid Electrolytes

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Pandis P.

2016-01-01

Full Text Available Apatite-type lanthanum silicates (ATLS materials have attracted interest in recent literature as solid electrolytes for SOFCs. The fabrication of an ATLS based fuel cell with the state-of-art electrodes (NiO/YSZ as anode and LSCF or LSM as cathode can show degradation after long operation hours due to Si diffusion mainly towards the anode. In this work, we report a “layer-by-layer anodic electrodes” fabrication by means of spin coating and physical spraying. The overall aim of this work is the successful fabrication of such a layered structure including suitable blocking layers towards the inhibition of Si interdiffusion from the apatite electrolyte to the anode. The results showed that the deposition of 3 layers of LFSO/GDC (3μm, NiO/GDC (4μm and the final NiO/YSZ anode layer provided a stable half-cell, with no solid state reaction occurring among the electrodes and no Si diffusion observed towards the anode after thermal treatment at 800°C for 120h.

Thermal and exhumation history of Sakhalin Island (Russia) constrained by apatite U-Pb and fission track thermochronology

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Glorie, Stijn; Alexandrov, Igor; Nixon, Angus; Jepson, Gilby; Gillespie, Jack; Jahn, Bor-Ming

2017-08-01

Sakhalin Island represents a key locality to study the tectonic evolution of the western Pacific. The island is located at the Amur-Okhotsk plate margin and records a complex thermotectonic history. Apatite double dating (U-Pb and fission track) and thermal history modelling were applied to three late Eocene granitoid massifs within central and southern Sakhalin: the Aniva, Okhotsk and Langeri complexes. Apatite U-Pb results yield consistent late Eocene (∼40-37 Ma) ages, suggesting rapid post-magmatic cooling. Apatite fission track results reveal bimodal age distributions with late Eocene - early Oligocene (∼38-33 Ma) and early Miocene (∼20-17 Ma) age populations that can be correlated with variations in Uranium and Chlorine concentrations. Thermal history modelling translates the AFT age bimodality into two-phase cooling histories. The timing of the early cooling phase (∼38-33 Ma) corresponds with the apatite U-Pb ages, indicating rapid cooling to at least ∼100 °C during the late Oligocene. The second cooling phase at ∼20-17 Ma cooled the samples to near-surface temperatures. Both cooling phases correspond with regional unconformities and subsequent accelerations in sedimentation rate, suggesting that cooling was a response to rapid exhumation. In addition, our data suggests that the studied terranes record differential exhumation with respect to the structural architecture. The Miocene exhumation pulse is coeval with the timing of transpressional fault displacement and the subsequent opening of the Kuril Basin.

αTCP ceramic doped with dicalcium silicate for bone regeneration applications prepared by powder metallurgy method: in vitro and in vivo studies.

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Velasquez, Pablo; Luklinska, Zofia B; Meseguer-Olmo, Luis; Mate-Sanchez de Val, Jose E; Delgado-Ruiz, Rafael A; Calvo-Guirado, Jose L; Ramirez-Fernandez, Ma P; de Aza, Piedad N

2013-07-01

This study reports on the in vitro and in vivo behavior of α-tricalcium phosphate (αTCP) and also αTCP doped with either 1.5 or 3.0 wt % of dicalcium silicate (C2 S). The ceramics were successfully prepared by powder metallurgy method combined with homogenization and heat treatment procedures. All materials were composed of a single-phase, αTCP in the case of a pure material, or solid solution of C2 S in αTCP for the doped αTCP, which were stable at room temperature. The ceramics were tested for bioactivity in simulated body fluid, cell culture medium containing adult mesenchymal stem cells of human origin, and in animals. Analytical scanning electron microscopy combined with chemical elemental analysis was used and Fourier transform infrared and conventional histology methods. The in vivo behavior of the ceramics matched the in vitro results, independently of the C2 S content in αTCP. Carbonated hydroxyapatite (CHA) layer was formed on the surface and within the inner parts of the specimens in all cases. A fully mineralized new bone growing in direct contact with the implants was found under the in vivo conditions. The bioactivity and biocompatibility of the implants increased with the C2 S content in αTCP. The C2 S doped ceramics also favoured a phase transformation of αTCP into CHA, important for full implant integration during the natural bone healing processes. αTCP ceramic doped with 3.0 wt % C2 S showed the best bioactive in vitro and in vivo properties of all the compositions and hence could be of interest in specific applications for bone restorative purposes. Copyright © 2012 Wiley Periodicals, Inc.

Oxygen isotope variations in phosphate of biogenic apatites. Pt. 2. Phosphorite rocks

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Kolodny, Y; Luz, B; Shemesh, A [Hebrew Univ., Jerusalem (Israel). Dept. of Geology

1983-09-01

Phosphorites from sedimentary sequences ranging in age from Archaen to Recent were analysed for delta/sup 18/O in both the PO/sub 4/ (delta/sup 18/Osub(p)) and CO/sub 3/ (delta/sup 18/Osub(c)) in the apatite lattice. The oxygen isotope record is considerably better preserved in phosphates than in either carbonates or cherts. The use of the Longinelli and Nuti temperature equation yields temperatures for Recent phosphorites that are in good agreement with those measured in the field. The delta/sup 18/Osub(p) values of ancient phosphorites decrease with increasing age. These changes with time are not likely to be due to post-depositional exchange. Changes in delta/sup 18/O values of seawater and variations of temperatures with time can account for the delta/sup 18/Osub(p) time trend, but the latter explanation is preferred. In Ancient phosphorites delta/sup 18/Osub(c) in structurally bound carbonate in apatite is not a reliable geochemical indicator.

An extensive apatite fission-track study throughout the Northern Apennines Nappe belt

International Nuclear Information System (INIS)

Abbate, E.; Balestrieri, M.L.; Bigazzi, G.; Ventura, B.; Zattin, M.; Zuffa, G.G.

1999-01-01

This paper takes into consideration more than 100 apatite fission-track analyses on samples coming from an approximately west-east cross-section throughout the Northern Apennines. This collisional chain is made of structural units and nappes (Ligurian and Tuscan Nappe) accreted to the Adriatic Foreland during the Neogene, which overthrust the Miocene turbiditic successions of the Cervarola and Marnoso-arenacea Formations. Different cooling ages and degrees of annealing delineate different evolution histories for these units. Exhumation of the western outcrops of the Ligurian Nappe can be placed at 8 Ma and follows a first denudation event occurred in Eocene times. Timing of exhumation decreases eastwards. A break in this general trend is shown by the Apuan Alps, that occupy an intermediate position and yielded the youngest cooling ages. In the external part of the Marnoso-arenacea foredeep deposits this tendency could not be tested because total annealing of the apatite system has not been reached. In this case, modeling of data allows evaluating maximum burial temperatures

Characterizing the inorganic/organic interface in cancer bone metastasis

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Wu, Fei

Bone metastasis frequently occurs in patients with advanced breast cancer and remains a major source of mortality. At the molecular level, bone is a nanocomposite composed of inorganic bone mineral deposited within an organic extracellular matrix (ECM). Although the exact mechanisms of bone metastasis remain unclear, the nanoscale materials properties of bone mineral have been implicated in this process. Bone apatite is closely related to synthetic hydroxyapatite (HAP, Ca10(PO4)6(OH)2) in terms of structural and mechanical properties. Additionally, although the primary protein content of bone is collagen I, the glycoprotein fibronectin (Fn) is essential in maintaining the overall integrity of the bone matrix. Importantly, in vivo, neither breast cancer cells nor normal bone cells interact directly with the bone mineral but rather with the protein film adsorbed onto the mineral surface. Therefore, we hypothesized that breast cancer cell functions were regulated by differential fibronectin adsorption onto hydroxyapatite, which led to pathological remodeling of the bone matrix and sustained bone metastasis. Three model systems containing HAP and Fn were developed for this thesis. In model system I, a library of synthetic HAP nanoparticles were utilized to investigate the effect of mineral size, shape, and crystallinity on Fn conformation, using Forster resonance energy transfer (FRET) spectroscopy. In model system II, Fn-functionalized large geologic HAP crystals were used instead of HAP nanoparticles to avoid cellular uptake when investigating subsequent cell functions. Overall our FRET analysis (models I and II) revealed that Fn conformation depended on size, surface chemistry, and roughness of underlying HAP. When breast cancer cells were seeded on the Fn-coated HAP crystal facets (model II), our data indicated high secretion levels of proangiogenic and proinflammatory factors associated with the presence of unfolded Fn conformations, likely caused by differential

Effects of Apatite Cement Containing Atelocollagen on Attachment to and Proliferation and Differentiation of MC3T3-E1 Osteoblastic Cells

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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.

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.

Petrology and geochemistry of primary magmas trapped in melt inclusions in scoria of Beaunit Maar (Chaîne des Puys, Massif Central, France)

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Jannot, S.; Schiano, P.; Boivin, P.; Clocchiatti, R.; Chazot, G.

2003-04-01

The Massif Central area, characterized by a typical intraplate alkaline serie, is the largest magmatic province of the West-European Rift system. Although it has been the subject of several studies, the nature of Massif Central sources is still a matter of debate and many hypotheses are proposed, including deep-rooted continental hotspot, metasomatised spinel lherzolites and an asthenospheric flow linked to the lithospheric root of the Alpine chain. The Chaîne des Puys is the last magmatic province of the French Massif Central and is composed of hundred young well-preserved volcanoes. The present work aims to supply information on the nature and the origin of the source chemistry of alkaline serie from the Chaîne des Puys, by characterizing the trace and major element composition of minute melts preserved as quenched glass inclusions inside olivines phenocrysts in scoria from the Beaunit Maar. Heating stage experiments performed at ambient pressure on partially crystallised primary melt inclusions suggest CO_2 oversaturation of the trapped melt, and an entrapment temperature around 1200^oC±10^oC. Daughter minerals analyses point to a Ti-and Ca-rich basaltic paragenesis, in good agreement with that of erupted basalts from the Chaîne des Puys. Major element compositions show that melts trapped in inclusions evolve by limited fractional crystallization. Inclusions trapped in the more primitive olivine phenocrysts (Fo85) have alkali-basalt compositions that fall on the primitive end of the compositional trend define by the lavas of the Chaîne des Puys. Their major element chemistry rules out the hypothesis of a mantle source in the spinel stability field and requires a garnet-bearing mantle source. Analyzed for trace-element composition by LA-ICP-MS, they display homogeneous, enriched patterns, similar to those characterizing oceanic island and continental basalts. They have high concentration of LILE and LREE/HREE ratios. Such trace-element feature are typical of

COMPARISON OF APATITE II™ TREATMENT SYSTEM AT TWO MINES FOR METALS REMOVAL

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Two abandoned lead-zinc mine sites, the Nevada Stewart Mine (NSM) and Success Mine, are located within the Coeur d'Alene Mining District, in northern Idaho. An Apatite II™ Treatment System (ATS) was implemented at each site to treat metal-laden water, mainly zinc. In the ATS, f...

Spitzer IRS Spectroscopy of the 10 Myr-Old EF Cha Debris Disk: Evidence for Phyllosilicate-Rich Dust in the Terrestrial Zone

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Currie, Thayne; Lisse, Carey M.; Sicillia-Aguilar, Aurora; Rieke, George H.; Su, Kate Y. L.

2011-01-01

We describe Spitzer IRS spectroscopic observations of the approx. 10 Myr-old star, EF Chao Compositional modeling of the spectra from 5 micron to 35 micron confirms that it is surrounded by a luminous debris disk with L(sub D)/L(sub *) approx. 10(exp -3), containing dust with temperatures between 225 K and 430 K characteristic of the terrestrial zone. The EF Cha spectrum shows evidence for many solid-state features, unlike most cold, low-luminosity debris disks but like some other 10-20 Myr-old luminous, warm debris disks (e.g. HD 113766A). The EF Cha debris disk is unusually rich in a species or combination of species whose emissivities resemble that of finely-powdered, laboratory-measured phyllosilicate species (talc, saponite, and smectite), which are likely produced by aqueous alteration of primordial anhydrous rocky materials. The dust and, by inference, the parent bodies of the debris also contain abundant amorphous silicates and metal sulfides, and possibly water ice. The dust's total olivine to pyroxene ratio of approx. 2 also provides evidence of aqueous alteration. The large mass volume of grains with sizes comparable to or below the radiation blow-out limit implies that planetesimals may be colliding at a rate high enough to yield the emitting dust but not so high as to devolatize the planetesimals via impact processing. Because phyllosilicates are produced by the interactions between anhydrous rock and warm, reactive water, EF Cha's disk is a likely signpost for water delivery to the terrestrial zone of a young planetary system.

Calcium silicate ceramic scaffolds toughened with hydroxyapatite whiskers for bone tissue engineering

International Nuclear Information System (INIS)

Feng, Pei; Wei, Pingpin; Li, Pengjian; Gao, Chengde; Shuai, Cijun; Peng, Shuping

2014-01-01

Calcium silicate possessed excellent biocompatibility, bioactivity and degradability, while the high brittleness limited its application in load-bearing sites. Hydroxyapatite whiskers ranging from 0 to 30 wt.% were incorporated into the calcium silicate matrix to improve the strength and fracture resistance. Porous scaffolds were fabricated by selective laser sintering. The effects of hydroxyapatite whiskers on the mechanical properties and toughening mechanisms were investigated. The results showed that the scaffolds had a uniform and continuous inner network with the pore size ranging between 0.5 mm and 0.8 mm. The mechanical properties were enhanced with increasing hydroxyapatite whiskers, reached a maximum at 20 wt.% (compressive strength: 27.28 MPa, compressive Young's modulus: 156.2 MPa, flexural strength: 15.64 MPa and fracture toughness: 1.43 MPa·m 1/2 ) and then decreased by addition of more hydroxyapatite whiskers. The improvement of mechanical properties was due to whisker pull-out, crack deflection and crack bridging. Moreover, the degradation rate decreased with the increase of hydroxyapatite whisker content. A layer of bone-like apatite was formed on the scaffold surfaces after being soaked in simulated body fluid. Human osteoblast-like MG-63 cells spread well on the scaffolds and proliferated with increasing culture time. These findings suggested that the calcium silicate scaffolds reinforced with hydroxyapatite whiskers showed great potential for bone regeneration and tissue engineering applications. - Highlights: • HA whiskers were incorporated into CS to improve the properties. • The scaffolds were successfully fabricated by SLS. • Toughening mechanisms was whisker pull-out, crack deflection and bridging. • The scaffolds showed excellent apatite forming ability

Calcium silicate ceramic scaffolds toughened with hydroxyapatite whiskers for bone tissue engineering

Energy Technology Data Exchange (ETDEWEB)

Feng, Pei [State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083, PR China, (China); Wei, Pingpin [Cancer Research Institute, Central South University, Changsha 410078 (China); Li, Pengjian; Gao, Chengde [State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083, PR China, (China); Shuai, Cijun, E-mail: shuai@csu.edu.cn [State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083, PR China, (China); Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425 (United States); Peng, Shuping, E-mail: shuping@csu.edu.cn [Cancer Research Institute, Central South University, Changsha 410078 (China)

2014-11-15

Calcium silicate possessed excellent biocompatibility, bioactivity and degradability, while the high brittleness limited its application in load-bearing sites. Hydroxyapatite whiskers ranging from 0 to 30 wt.% were incorporated into the calcium silicate matrix to improve the strength and fracture resistance. Porous scaffolds were fabricated by selective laser sintering. The effects of hydroxyapatite whiskers on the mechanical properties and toughening mechanisms were investigated. The results showed that the scaffolds had a uniform and continuous inner network with the pore size ranging between 0.5 mm and 0.8 mm. The mechanical properties were enhanced with increasing hydroxyapatite whiskers, reached a maximum at 20 wt.% (compressive strength: 27.28 MPa, compressive Young's modulus: 156.2 MPa, flexural strength: 15.64 MPa and fracture toughness: 1.43 MPa·m{sup 1/2}) and then decreased by addition of more hydroxyapatite whiskers. The improvement of mechanical properties was due to whisker pull-out, crack deflection and crack bridging. Moreover, the degradation rate decreased with the increase of hydroxyapatite whisker content. A layer of bone-like apatite was formed on the scaffold surfaces after being soaked in simulated body fluid. Human osteoblast-like MG-63 cells spread well on the scaffolds and proliferated with increasing culture time. These findings suggested that the calcium silicate scaffolds reinforced with hydroxyapatite whiskers showed great potential for bone regeneration and tissue engineering applications. - Highlights: • HA whiskers were incorporated into CS to improve the properties. • The scaffolds were successfully fabricated by SLS. • Toughening mechanisms was whisker pull-out, crack deflection and bridging. • The scaffolds showed excellent apatite forming ability.

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)

Comparison of three calcium phosphate bone graft substitutes from biomechanical, histological, and crystallographic perspectives using a rat posterolateral lumbar fusion model

Energy Technology Data Exchange (ETDEWEB)

Hu, Ming-Hsien [Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Department of Orthopedics, Show-Chwan Memorial Hospital, Changhua 50544, Taiwan (China); Department of Orthopedic Surgery, Faculty of Medicine, National Yang-Ming University, Taipei 112, Taiwan (China); Lee, Pei-Yuan [Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Department of Orthopedics, Show-Chwan Memorial Hospital, Changhua 50544, Taiwan (China); Chen, Wen-Cheng, E-mail: wincheng0925@yahoo.com.tw [Department of Fiber and Composite Materials, College of Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Hu, Jin-Jia, E-mail: jjhu@mail.ncku.edu.tw [Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Medical Device Innovation Center, National Cheng Kung University, Tainan 701, Taiwan (China)

2014-12-01

This study evaluated the effectiveness of three calcium phosphate bone graft substitutes with different chemical compositions on spinal fusion using a rat posterolateral lumbar fusion model. Specifically, two recently developed non-dispersive tetracalcium phosphate/dicalcium phosphate anhydrous-based calcium phosphate cements (CPCs), namely a CPC consisting of equimolar amounts of the two compounds (nd-CPC) and a CPC consisting of a two-fold greater amount of dicalcium phosphate anhydrous (DCP-rich CPC), were compared with a commercial calcium phosphate bone graft (c-CPG) consisting of hydroxyapatite (60%) and β-tricalcium phosphate (40%). Single-level posterolateral lumbar fusion was performed at the L4–L5 vertebrae in fifteen adult rats (n = 5 for each group). Spinal fusion was evaluated with radiographs, manual palpation, mechanical testing, micro-CT, and histology 8 weeks post-surgery. In particular, the crystallographic phases in the three substitutes were identified before and 8 weeks after their implantation. Manual palpation revealed stable constructs in nearly all of the spine specimens. The stiffness and bending load of fused spines in the two CPC groups were comparable to those in the c-CPG group. The radiographs specifically revealed implant resorption and bone remodeling in the DCP-rich CPC group. Analysis of 3D micro-CT images revealed that the bone volume ratio in the DCP-rich CPC group was significantly greater than those in the nd-CPC and c-CPG groups. Histology showed that the DCP-rich CPC group exhibited the highest degree of bone regeneration and osseointegration. Notably, DCP-rich CPC led to a pronounced phase transformation, generating the greatest amount of poorly crystalline apatite among the three groups, which together with adequate resorption may explain the aforementioned positive findings. We therefore conclude that of the bone graft substitutes considered, DCP-rich CPC has the greatest potential to be used in spinal fusion

Genesis of iron-apatite ores in Posht-e-Badam Block (Central Iran ...

Indian Academy of Sciences (India)

Central Iran; iron-apatite ore; Kiruna-type; Posht-e-Badam Block; REE geochemistry. J. Earth Syst ... ferent ore genesis models have been proposed for ...... volatile-rich magma systems stress the important .... Laco magnetite flow deposits, northern Chile: An up-to- ... economic report on iron ore prevision of the Esfahan steel.

A New Biphasic Dicalcium Silicate Bone Cement Implant

Directory of Open Access Journals (Sweden)

Fausto Zuleta

2017-07-01

Full Text Available This study aimed to investigate the processing parameters and biocompatibility of a novel biphasic dicalcium silicate (C2S cement. Biphasic α´L + β-C2Sss was synthesized by solid-state processing, and was used as a raw material to prepare the cement. In vitro bioactivity and biocompatibility studies were assessed by soaking the cement samples in simulated body fluid (SBF and human adipose stem cell cultures. Two critical-sized defects of 6 mm Ø were created in 15 NZ tibias. A porous cement made of the high temperature forms of C2S, with a low phosphorous substitution level, was produced. An apatite-like layer covered the cement’s surface after soaking in SBF. The cell attachment test showed that α´L + β-C2Sss supported cells sticking and spreading after 24 h of culture. The cement paste (55.86 ± 0.23 obtained higher bone-to-implant contact (BIC percentage values (better quality, closer contact in the histomorphometric analysis, and defect closure was significant compared to the control group (plastic. The residual material volume of the porous cement was 35.42 ± 2.08% of the initial value. The highest BIC and bone formation percentages were obtained on day 60. These results suggest that the cement paste is advantageous for initial bone regeneration.

Nanosized Mesoporous Bioactive Glass/Poly(lactic-co-glycolic Acid Composite-Coated CaSiO3 Scaffolds with Multifunctional Properties for Bone Tissue Engineering

Directory of Open Access Journals (Sweden)

Mengchao Shi

2014-01-01

Full Text Available It is of great importance to prepare multifunctional scaffolds combining good mechanical strength, bioactivity, and drug delivery ability for bone tissue engineering. In this study, nanosized mesoporous bioglass/poly(lactic-co-glycolic acid composite-coated calcium silicate scaffolds, named NMBG-PLGA/CS, were successfully prepared. The morphology and structure of the prepared scaffolds were characterized by scanning electron microscopy and X-ray diffraction. The effects of NMBG on the apatite mineralization activity and mechanical strength of the scaffolds and the attachment, proliferation, and alkaline phosphatase activity of MC3T3 cells as well as drug ibuprofen delivery properties were systematically studied. Compared to pure CS scaffolds and PLGA/CS scaffolds, the prepared NMBG-PLGA/CS scaffolds had greatly improved apatite mineralization activity in simulated body fluids, much higher mechanical property, and supported the attachment of MC3T3 cells and enhanced the cell proliferation and ALP activity. Furthermore, the prepared NMBG-PLGA/CS scaffolds could be used for delivering ibuprofen with a sustained release profile. Our study suggests that the prepared NMBG-PLGA/CS scaffolds have improved physicochemical, biological, and drug-delivery property as compared to conventional CS scaffolds, indicating that the multifunctional property of the prepared scaffolds for the potential application of bone tissue engineering.

Beta transmutations in apatites with ferric iron as an electron acceptor - implication for nuclear waste form development.

Science.gov (United States)

Yao, Ge; Zhang, Zelong; Wang, Jianwei

2017-09-27

Apatite-structured materials have been considered for the immobilization of a number of fission products from reprocessing nuclear fuel because of their chemical durability as well as compositional and structural flexibility. It is hypothesized that the effect of beta decay on the stability can be mitigated by introducing an appropriate electron acceptor at the neighboring sites in the structure. The decay series 137 Cs → 137 Ba and 90 Sr → 90 Y → 90 Zr were investigated using a spin-polarized DFT approach to test the hypothesis. Apatites with compositions of Ca 10 (PO 4 ) 6 F 2 and Ca 4 Y 6 (SiO 4 ) 6 F 2 were selected as model systems for the incorporation of radionuclides Cs and Sr, respectively. Ferric iron was introduced in the structure as an electron acceptor. Electron density of states, crystal and defect structures, and energies before and after beta decay were calculated. The calculated electron density of states suggests that the extra electron is localized at the ferric iron, which changes its oxidation state and becomes ferrous iron. The crystal and defect structures were analyzed based on the volume, lattice parameters, radial distribution functions, metal cation to coordinating oxygen distances, and the metaprism twist angle of the apatite crystal structure. The results show that there are minor changes in the crystal and defect structures of CsFeCa 8 (PO 4 ) 6 F 2 with Cs + and Fe 3+ substitutions undergoing the Cs → Ba transmutation, and of Ca 3 SrY 4 Fe 2 (SiO 4 ) 6 F 2 with Sr 2+ and Fe 3+ substitutions undergoing the Sr → Y → Zr transmutations. The last decay change, from Y 3+ → Zr 4+ , causes relatively larger changes in the local defect structure around Zr involving the coordination environment but the change is not significant to the crystal structure. The results on calculated cohesive energy suggest that the transmutations Cs + → Ba 2+ and Sr 2+ → Y 3+ → Zr 4+ in both apatite compositions are energetically favorable

Crystallization and preliminary crystallographic studies of the single-chain variable fragment of antibody chA21 in complex with an N-terminal fragment of ErbB2

International Nuclear Information System (INIS)

Liu, Yang; Zhou, Huihao; Zhu, Juanjuan; Gao, Yongxiang; Niu, Liwen; Liu, Jing; Teng, Maikun

2009-01-01

An antibody–antigen complex consisting of a single-chain variable fragment of the potential therapeutic antibody chA21 and an N-terminal fragment (residues 1–192) of the human ErbB2 extracellular domain was expressed, purified and crystallized. X-ray diffraction data were collected to 2.45 Å resolution. ErbB2 is a transmembrane tyrosine kinase, the overexpression of which causes abnormality and disorder in cell signalling and leads to cell transformation. Previously, an anti-ErbB2 single-chain chimeric antibody chA21 that specifically inhibits the growth of ErbB2-overexpressing cancer cells in vitro and in vivo was developed. Here, an antibody–antigen complex consisting of the single-chain variable fragment (scFv) of chA21 and an N-terminal fragment (residues 1–192, named EP I) of the ErbB2 extracellular domain was crystallized using the sitting-drop vapour-diffusion method. An X-ray diffraction data set was collected to 2.45 Å resolution from a single flash-cooled crystal; the crystal belonged to space group P2 1 2 1 2 1

Devonian climate and reef evolution: Insights from oxygen isotopes in apatite