Cobalt-Based Single-Ion Magnets on an Apatite Lattice: Toward Patterned Arrays for Magnetic Memories

2017 ◽  
Vol 56 (3) ◽  
pp. 1232-1240 ◽  
Author(s):  
Pavel E. Kazin ◽  
Mikhail A. Zykin ◽  
Walter Schnelle ◽  
Yan V. Zubavichus ◽  
Konstantin A. Babeshkin ◽  
...  
Keyword(s):  
Apatite Lattice

Rietveld Refinement of Sintered Magnesium Substituted Calcium Apatite

2008 ◽  
Vol 396-398 ◽  
pp. 277-280 ◽  
Author(s):  
Marcia S. Sader ◽  
Elizabeth L. Moreira ◽  
Valéria C.A. Moraes ◽  
Jorge C. Araújo ◽  
Racquel Z. LeGeros ◽  
...  
Keyword(s):  
Rietveld Refinement ◽  
Tricalcium Phosphate ◽  
Rietveld Method ◽  
Lattice Parameter ◽  
Commercial Product ◽  
Precipitation Method ◽  
Osteoporosis Therapy ◽  
Biomineralization Process ◽  
Apatite Lattice

The incorporation of magnesium in the synthetic apatite has been associated with biomineralization process and osteoporosis therapy in human and animals. Magnesium easily replaces calcium in the apatite lattice and influences or controls the hydroxyapatite crystallization processes. In this work, Mg-substituted calcium deficient apatite, with Mg/Ca ratio = 0.1, 0.15 and 0.2 were synthesized by precipitation method. Then, sintered at 1000 oC and compared with a commercial product labeled as tricalcium phosphate sintered at the 1000 oC. The sintered products showed tricalcium phosphate (β-TCP) structure. The Mg2+ substitution in the Ca(4) and Ca(5) sites of β-TCP and the lattice parameter changes were estimated using the Rietveld method. Using this method, the formulas Ca2.73(Mg0.27)(PO4)2, Ca2.71(Mg0.29)(PO4)2 and Ca2.70(Mg0.23Mg0.07)(PO4)2 were calculated for the samples with Mg/Ca ratio = 0.1, 0.15 and 0.2 respectively.

scholarly journals Development of a new approach to diagnosis of the early fluorosis forms by means of FTIR and Raman microspectroscopy

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Pavel Seredin ◽  
Dmitry Goloshchapov ◽  
Yuri Ippolitov ◽  
Jitraporn Vongsvivut
Keyword(s):  
Early Stage ◽  
Type B ◽  
Surface Layers ◽  
Human Teeth ◽  
New Approach ◽  
Mean Values ◽  
Infrared Microspectroscopy ◽  
The Mean ◽  
Apatite Lattice ◽  
Preventive Diagnostics

AbstractThis study is aimed at investigating the features of mineralization of the enamel apatite at initial stages of fluorosis development. Samples of teeth with intact and fluorotic enamel in an early stage of the disease development (Thylstrup–Fejerskov Index = 1–3) were studied by Raman scattering and FTIR using Infrared Microspectroscopy beamline at Australian Synchrotron equipment. Based on the data obtained by optical microspectroscopy and calculation of the coefficient R [A-type/B-type], which represents the ratio of carbonation fraction of CO32−, replacing phosphate or hydroxyl radicals in the enamel apatite lattice, the features of mineralization of enamel apatite in the initial stages of development of the pathology caused by an increased content of fluorine in the oral cavity were established. Statistical analysis of the data showed significant differences in the mean values of R [A-type/B-type] ratio between the control and experimental groups for surface layers (p < 0.01). The data obtained are potentially significant as benchmarks in the development of a new approach to preventive diagnostics of the development of initial and clinically unregistered stages of human teeth fluorosis, as well as personalized control of the use of fluoride-containing caries-preventive agents.

Silicon Dissolution from Microporous Silicon Substituted Hydroxyapatite and its Effect on Osteoblast Behaviour

2006 ◽  
Vol 309-311 ◽  
pp. 117-120 ◽  
Author(s):  
Katharina Guth ◽  
Tom Buckland ◽  
Karen A. Hing
Keyword(s):  
Significant Variation ◽  
Direct Contact ◽  
Culture Medium ◽  
Initial Level ◽  
Culture Conditions ◽  
Dynamic Conditions ◽  
Medium Change ◽  
Static Conditions ◽  
Silicon Dissolution ◽  
Apatite Lattice

In this study silicon release from SiHA into tissue culture medium was investigated under static and semi-dynamic conditions. The effect of silicon release under semi-dynamic conditions on alkaline phosphatase activity (ALP) and collagen I (CICP) expression by osteoblast like cells (HOS TE85) was also examined. Under static conditions a low level of silicon was released within 24 hours, this initial level dropped over 3-7 days but subsequently increased again by 10-14 days. Under semi-dynamic conditions silicon was released within 24 hours and was subsequently reduced with each medium change until equilibrating at close to 0 after 10 days. ALP and CICP showed significant variation in expression between culture conditions. In direct contact with SiHA ALP peaked at day 10 and CICP was constantly elevated. Cells grown in the presence of but not on SiHA expressed progressively decreasing levels of ALP from 7-14 days, with CICP peaking at day 10. On thermanox (TMX) ALP constantly increased and CICP peaked at day 10. The results indicate that silicon leaches out of the lattice of the SiHA crystal structure but may also be reprecipitated onto the substrate. We have also demonstrated that Si influences osteoblast metabolism and differentiation whether it is available as free silicon or 'bound' in the apatite lattice.

TbO+ in a calcium apatite matrix featuring a triple trigger-type relaxation of magnetization

2019 ◽  
Vol 48 (16) ◽  
pp. 5299-5307 ◽  
Author(s):  
Pavel E. Kazin ◽  
Mikhail A. Zykin ◽  
Oxana V. Magdysyuk ◽  
Valentina V. Utochnikova ◽  
Evgeny A. Gorbachev ◽  
...  
Keyword(s):  
Magnetization Relaxation ◽  
Apatite Lattice

Magnetically bistable TbO+ embedded in the apatite lattice shows three switchable paths of the magnetization relaxation.

Structural changes induced by fluoride in rat bones

1984 ◽  
Vol 42 ◽  
pp. 718-719
Author(s):  
A. D. Reid ◽  
M. D. Grynpas ◽  
K. P. H. Pritzker ◽  
J. E. Harrison
Keyword(s):  
Bone Mineral ◽  
Structural Changes ◽  
Mature Female ◽  
Female Rats ◽  
Control Group ◽  
Fixed Amount ◽  
Treatment Of Osteoporosis ◽  
Skeletal Mass ◽  
Apatite Lattice ◽  
Bone Apatite

Fluoride is an essential trace element for normal skeletal growth and maintenance. As fluoride intake can lead to increased skeletal mass, fluoride in the form of NaF is being used clinically in the treatment of osteoporosis. The mechanisms by which fluoride affects bone is poorly understood. NaF administration has been found to increase the rate of bone formation along with an increase in the number of osteoblast cells. Fluoride has been also shown to increase the crystallinity of bone apatite by substituting for hydroxylions in the apatite lattice, rendering bone mineral less soluble and more stable.In our study we undertook to elucidate further the effects of fluoride on bone mineral. Eight mature female rats (250-300 g) were divided into control and fluoride-treated groups with 4 rats in each group. The fluoridetreated rats were given a fixed amount of supplemental NaF in their water and food: the control group was given distilled water and no supplemental fluoride. The animals were sacrificed 7 weeks later.

scholarly journals Synthesis of Peroxyapatite by Hydrothermal Processing

2014 ◽  
Vol 631 ◽  
pp. 88-92 ◽  
Author(s):  
Kārlis Gross ◽  
Anastasija Jersova ◽  
Arturs Viksna
Keyword(s):  
Hydrogen Peroxide ◽  
Hydrothermal Process ◽  
Antibacterial Properties ◽  
Hydrothermal Processing ◽  
Ammonium Persulphate ◽  
Oxygen Generation ◽  
New Process ◽  
High Temperature Processing ◽  
Apatite Lattice ◽  
Low Temperature Process

Peroxide ions in apatite provides an additional resource for imparting an antibacterial capability in apatite. A hydrothermal process has been developed for including peroxide ions into the apatite lattice. Three oxygen generation compounds, hydrogen peroxide, ammonium persulphate and paracetic acid were investigated for peroxyapatite generation. Hydrogen peroxide provides the highest peroxide containing apatite. Both the oxygen generation and the apatite lattice formation represented the two critical factors for producing peroxyapatite. Unlike with high temperature processing, the cooling rate did not influence the retained peroxide content. This new process provides a building block for investigating antibacterial properties of peroxyapatite in a low temperature process.

The Synthesis and Characterisation of Ge Containing Apatite-Type Oxide Ion Conductors

2002 ◽  
Vol 756 ◽  
Author(s):  
P. R. Slater ◽  
J. E. H. Sansom ◽  
J. R. Tolchard ◽  
M. S. Islam
Keyword(s):  
Sintering Temperature ◽  
Divalent Cations ◽  
The Novel ◽  
Ion Conductivities ◽  
Bi Doping ◽  
Significant Interest ◽  
Oxide Ion Conductors ◽  
Apatite Lattice ◽  
Oxide Ion ◽  
Apatite Type

ABSTRACTApatite-type oxides, La10-x(Si/Ge)6O26+z, have been attracting significant interest recently due to their high oxide ion conductivities. Most of the work so far has focused on the Si based systems, since the Ge based systems suffer from problems attributed to Ge loss. In this paper we show that doping divalent cations on the La site or B on the Ge site helps to stabilise the hexagonal apatite lattice for these Ge based systems. These doped phases show high oxide ion conductivities, although results from extended sintering studies suggest that Ge loss is still a problem. In order to limit Ge loss, we have also examined Bi doping to lower the sintering temperature and preliminary results for the novel Bi containing apatite-type phases, La6Bi2M2Ge6O26 (M=Mg, Sr, Ba) and La8-xBi2Ge5GaO26+y, are also reported.

scholarly journals Carbonated apatite lattice parameter variation across incremental growth lines in teeth

Materialia ◽  
2020 ◽  
Vol 14 ◽  
pp. 100935
Author(s):  
J. Ryan ◽  
M.M. Stulajter ◽  
J.S. Okasinski ◽  
Z. Cai ◽  
G.B. Gonzalez ◽  
...  
Keyword(s):  
Lattice Parameter ◽  
Parameter Variation ◽  
Lattice Parameter Variation ◽  
Carbonated Apatite ◽  
Incremental Growth ◽  
Apatite Lattice

Über die Wechselwirkung des Vanadyl(IV)-Kations mit Calcium-Hydroxylapatit / The Interaction of the Vanadyl(IV) Cation with Calcium Hydroxylapatite

1992 ◽  
Vol 47 (3) ◽  
pp. 395-398 ◽  
Author(s):  
G.E. Narda ◽  
E. D. Vega ◽  
J. C. Pedregosa ◽  
S. B. Etcheverry ◽  
E. J. Baran
Keyword(s):  
High Stability ◽  
Esr Spectroscopy ◽  
Esr Spectra ◽  
Inhomogeneous Distribution ◽  
Adsorbed Species ◽  
Experimental Conditions ◽  
X Ray ◽  
Calcium Hydroxylapatite ◽  
Apatite Lattice

Abstract Solid products obtained from calcium hydroxylapatite suspensions in diluted VO2+ solutions, under different experimental conditions, were investigated by means of X-ray powder diffractometry and IR and ESR spectroscopy. It is demonstrated that the VO2+ cation cannot be incorporated into the apatite-lattice but is strongly adsorbed on the surface of the material. Different aspects of this adsorption were thoroughly investigated. The ESR spectra suggest an inhomogeneous distribution of the adsorbed species and the generation of O = V (O)4 moieties, which show a high stability towards oxidation.

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