共查询到20条相似文献,搜索用时 312 毫秒
1.
D. I. Paik D. S. Ma D. Y. Park H. S. Moon Y. I. Chang J. B. Kim 《Journal of Radioanalytical and Nuclear Chemistry》1997,217(2):221-223
The purpose of this study was to evaluate the effectiveness of a toothpaste containing bamboo salt on fluorine uptake in bovine enamel and to compare the efficiency of fluorine uptake between sodium monofluorophosphate (SMFP) toothpaste and sodium fluoride (NaF) mouthrinsing solution using proton induced -ray emission analysis. 30 bovine tooth enamel specimens were prepared and assigned to 5 groups as follows: (a) specimens without any treatment, (b) specimens which were treated with a toothpaste containing dicalcium phosphate dihydrate (DCPD) only, (c) specimens which were treated with a toothpaste containing DCPD and SMFP, (d) specimens which were treated with a toothpaste containing DCPD, SMFP and 2% bamboo salt, (e) specimens which were treated with 0.05% NaF mouthrinsing solution. After 5 and 10 hours of treatment, fluorine concentration was measured at the depth of 263, 625, 2530 nm from the surface of the specimens. The surface concentration of fluorine was markedly increased using SMFP dentifrice. Bamboo salt did not encourage the uptake of fluorine into the enamel surface. NaF mouthrinsing solution showed a considerably higher uptake of fluoride in the intact enamel surface than the SMFP dentifrices. 相似文献
2.
I. Roelandts G. Robaye G. Weber J. M. Delbrouck J. C. Duchesne 《Journal of Radioanalytical and Nuclear Chemistry》1987,112(2):453-460
More than 200 specimens from different occurrences of the Rogaland igneous complex and surrounding granulite facies metamorphic rocks (S. W. Norway) have been analysed by a direct non-destructive proton induced gamma-ray emission (PIGE) technique. The fluorine contents vary from <25 ppm to 3500 ppm. There is a good correlation between the concentration of fluorine and that of phosphorus for igneous rocks, suggesting a control of apatite on the F content. In metamorphic rocks, amphibole and biotite besides apatite are the principal cencentrators of fluorine indicating that fluorine in the system is controlled by granulite facies metamorphism conditions.Research Associate of the National Fund for Scientific Research (Belgium) 相似文献
3.
W. Arshed O. A. Akanle N. M. Spyrou 《Journal of Radioanalytical and Nuclear Chemistry》1994,179(2):349-355
Proton induced gamma-ray emission (PIGE) and proton induced X-ray emission (PIXE) analysis was employed to investigate the distribution of the concentration of fluorine and ten other elements along sections of teeth samples, extracted from eight individuals. These sections which included the bulk of dentine and enamel were scanned using a proton beam of 250 m diameter. Rutberford backscattering spectra were also collected in order to obtain information about the concentration of major elements and to correct for matrix inhomogeneities. 相似文献
4.
The direct non-destructive proton-induced gamma-ray emission (PIGE) technique with a germanium detector was applied to the determination of total fluorine concentration in five coal reference materials (BCR 40, NIST 1632b, NIST 1635, SARM 20 and USGS CLB-1). Duplicate analyses were made from five randomly selected bottles of each coal. Individual data are presented and some problems (calibration, proton stopping power, effects of sample heating by the proton beam, background estimation) which were encountered during this study are discussed. Sensitivity and reproducibility of the determinations, and homogeneity of the coal samples with respect to fluorine contents by analysis of variance were investigated. The present data are also compared with the few published values for these reference samples, including other PIGE data. The use of synthetic standards and spiked samples in the present study suggested that the PIGE method was more accurate than other techniques. 相似文献
5.
用光电子能谱和扫描电镜分析体外人牙釉质片经含不同浓度氟化物的脱矿液和再矿化液处理后釉质化学成分和形态学变化。结果发现,脱矿液中单独加入低浓度氟化物不能有效抑钙和磷溶解,在有外源性钙和磷存在时,才能获得再矿化而抑制钙和磷溶解,脱矿环境中有高浓度氟,通过局部沉积氟化钙而抑制酸与牙的反应,氟促进再矿化主要表现在加速钙的沉积,同时本身参以形成氟磷灰石,提高了牙齿的耐酸能力。 相似文献
6.
Particle induced X-ray emission analysis (PIXE) and nuclear reaction analysis have been applied to multielemental analysis
of human dental enamel in a proton microprobe. The PIXE technique was excercised for the characterization of multielemental
lateral distributions on and just below the sample surface. For the assessment of depth distributions of fluorine the resonant
nuclear reaction19F(p,aλ)16O was used. The combination of two analytical techniques comprising both atomic and nuclear interactions in a microprobe was
applied to enamel samples of different origins. One sample constituted a healthy enamel and the other one enamel from a restored
tooth. The microprobe in the combined mode was demonstrated to permit the establishment of lateral, concentration gradients
of elements heavier than phosphorus with a resolution of 15 μm in enamel and simultaneously of depth distributions of fluorine
better than 0.7 μm. The detection limits approached, 10–25 ppm for most of the elements considered.
Supported by the Swedish Natural Science Research Council 相似文献
7.
采用酸蚀后的牙釉质作为早期龋缺损模型,在缺损牙釉质表面修饰-SO3-功能基团,分别在人工唾液和含氟人工唾液中进行原位再矿化的研究。利用X-射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、能谱仪(EDS)、选区电子衍射(SAED)研究原位再矿化晶体的组成和结构。结果表明,在人工唾液和含氟人工唾液中,表面修饰的官能团均可有效促进牙釉质再矿化。在含氟人工唾液中生成了沿c轴取向生长的具有较大长径比的棒状氟羟基磷灰石(FHA),这种FHA晶体具有类牙釉质的成分和结构,对修复早期龋有重要的意义。 相似文献
8.
Using the high resolution microprobe which combines PIXE with PIGE measurements, components of trapped fluids can be measured without opening individual inclusions. It is a useful tool for nondestructive all elements' analysis. Micro-PIXE was used to detect the Z> 13 elements and the fluorine concentration was analyzed with micro-PIGE, using the 19F(p, γ)16O reaction at 872 keV resonance energy. Primary work of the elemental distributions including light elements in fluid inclusions is also given. 相似文献
9.
含氟丙烯酸酯共聚乳液及其膜表面特性的研究 总被引:17,自引:0,他引:17
以十二烷基硫酸钠 (SDS)和OP 10混合乳化剂 ,制备了甲基丙烯酸全氟辛基乙酯 (FMA8) 甲基丙烯酸丁酯 (BMA) 甲基丙烯酸 (MAA)共聚乳液 .通过DSC、FT IR、1 H NMR对共聚物的结构、组成进行了表征研究 .采用JZHY 180界面张力仪研究了共聚乳液膜表面的性质 ,结果表明 ,随着共聚物中全氟单体含量的增加 ,共聚物膜的表面能显著降低 ,当全氟单体的含量达到 2 5wt %时 ,其表面能降低到 19 74mJ m2 .X ray光电子能谱(XPS)对共聚物表面原子组成的分析结果表明 ,共聚物表面氟的含量远高于其平均含量 ,证明了含氟基团的趋表现象 .经退火处理 ,共聚物膜表面的氟含量增加 ,表面自由能降低 相似文献
10.
M. A. Chaudhri M. N. Chaudhri Q. Nadeem Q. Jabbar 《Journal of Radioanalytical and Nuclear Chemistry》2007,271(3):701-703
A new method for non-destructive depth profiling of fluorine has been developed which extends the profiling range to much
larger depths than hitherto possible. In this method the thick-target yield of 6–7 MeV gammas from the reaction of 19F(p,αγ) 16O in the tooth sample, was measured as a function of the incident energy from threshold to up to 2.7 MeV and the yield curve
plotted. This curve was compared to the calculated yield curve of 6–7 MeV gammas from the same reaction but on an enamel matrix
containing uniformly distributed fluorine. The difference in the shape of the two curves was only due to the non-uniform distribution
of fluorine in the tooth sample, which could then be calculated. By making use of this method F-depth profiles in teeth of
monkeys were determined non-destructively to a depth of 14 μm. This method is also applicable for profiling other elements
through appropriate resonant or non-resonant nuclear reactions. 相似文献
11.
《Analytical letters》2012,45(11):831-838
Abstract The surfaces of both normal and fluoride treated human dental enamel were examined with x-ray photoelectron spectroscopy (ESCA). Using argon-ion etching to remove thin layers of enamel, subsurface layers were also analyzed. The resulting composition-depth profile showed that stannous fluoride produced a subsurface layer containing both tin and fluoride whereas fluorine was absent from the surface layer. Acid fluoride treatments, however, converted the surface to calcium fluoride which steadily decreased in concentration with depth. 相似文献
12.
F. M. Elzawawy E. A. Saad I. H. Badr 《Journal of Radioanalytical and Nuclear Chemistry》1992,161(1):71-78
Fluorine is an important trace element for life and human well-being. Food, in general, provides about 40 percent of the fluorine intake in the human body. In order to measure fluorine levels in human diet samples, Instrumental Neutron Activation Analysis (INAA) and Proton Induced Gamma-ray Emission (PIGE) analysis were used. Reactions19F(n,)20F and19F(n, p)19O were employed for determination of the fluorine concentration using a reactor neutron spectrum and epithermal neutrons. Corrections were made for the sodium matrix interference caused by the23Na(n, )20F threshold reaction in the case of reactor neutron cyclic activation analysis and for the oxygen interference via18O(n, )19O reaction when using the epithermal cyclic NAA method. The fluorine content of the diet samples was also determined by PIGE analysis making use of the resonance reaction19F(p, )16O at 872 keV. Cyclic Neutron Activation Analysis (CNAA) when combined with mass fractionation was found to be the most suitable for determination of low concentration of fluorine, through the19F(n, )20F reaction with a detection limit of 2.2 ppm in Bowen's Kale elemental standard. 相似文献
13.
V. Havránek J. Kučera Z. Řanda V. Voseček 《Journal of Radioanalytical and Nuclear Chemistry》2004,259(2):325-329
Capabilities of instrumental neutron activation analysis (INAA), photon activation analysis with radiochemical separation
(RPAA) and proton induced γ-ray emission (PIGE) for determination of fluorine in biological and environmental materials are
compared in terms of detection limits, nuclear and other interferences. The lowest detection limit of 0.5 μg.g-1 was achieved by RPAA, the detection limit of the non destructive and interference-free PIGE method was by one order of magnitude
higher, whereas two to three orders of magnitude higher detection limits compared to RPAA were obtained in INAA. A satisfactory
agreement was found between the results obtained in this work and reference, mostly information values for several biological
and environmental materials. However, higher values of two orders of magnitude were determined by RPAA and PIGE in NIST RM-8414
Bovine Muscle compared to the fluorine information value. The reason for this difference is the contamination of this material
with Teflon, which occurred on its preparation and has not been taken into account in establishing the information value.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
14.
S. Chhillar R. Acharya S. Sodaye K. Sudarshan S. Santra R. K. Mishra C. P. Kaushik R. K. Choudhury P. K. Pujari 《Journal of Radioanalytical and Nuclear Chemistry》2012,294(1):115-119
Barium borosilicate glass (BaBSG) is proposed as a potential candidate for vitrification of nuclear waste generated from thoria based nuclear reactors. Along with fission products, activation products and many inactive chemicals, like fluorine in the form of HF are expected to be present in the dissolver solution with nuclear waste. As vitrification occurs at high temperature, it is important to quantify fluorine in BaBSG. Due to its complex matrix, most of the wet chemical and nuclear analytical methods encounter problems in the estimation of fluorine. Particle induced γ-ray emission (PIGE) method has been standardized for non-destructive determination of fluorine contents in BaBSG samples utilizing measurement of prompt gamma-rays from 19F (p, p’γ) 19F reaction. Experiments have been carried out with thick pellet targets prepared in cellulose matrix using 4 MeV proton beam from the folded tandem ion accelerator at BARC, Mumbai. For obtaining current normalized count rate of interest, beam current variation was monitored by the Rutherford backscattering spectrometry (RBS) method as well as by the in situ approach using an externally added element sensitive to PIGE. In this paper standardization of PIGE methods for F determination, validation of methods using synthetic samples, and application to BaBSG samples are reported. 相似文献
15.
Y. Li L. Wu Q. Wang Q. Zhou C.Y. Cao S. Zheng Z. Zhou H.M. Wong Q.L. Li 《Materials Today Chemistry》2022
The aging of the global population has caused dentin exposure and root caries to become significant patient-management issues in clinical dentistry. Biomimetic remineralization, as a non-invasive therapeutic method, is of great significance to solve the problem. Herein, a novel biomimetic-mineralizing strategy to induce the self-healing of dentin defects with similar tooth structure was developed through the easy one-step polydopamine (PDA)-assisted co-deposition of polyacrylic acid (PAA) (denoted as PDA@PAA) in vitro. Immersing demineralized dentin into PAA and dopamine (DA) mixed solutions. Hereafter, the modified demineralized dentin was immersed in the supersaturated solution of calcium and phosphate at 37 °C at designated time. Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and attenuated total reflection fourier transform infrared (ATR-FTIR) were performed to analyze the interaction and co-deposition between PDA and PAA. The remineralization of demineralized dentin was characterized by field emission scanning electron microscope (FE-SEM), TEM, X-ray diffraction (XRD), friction and wear test, nanoindentation, acid resistance. And the cytocompatibility of PDA@PAA was evaluated by cell counting kit-8 (CCK-8) and cell morphology observation. The results that PAA inhibited further PDA polymerization and aggregation, PDA@PAA were co-deposited onto the surface of demineralized dentin matrix. SEM and TEM showed that the demineralized-dentin modified with PDA@PAA was completely remineralized at 12 h, not only the dentin tubules were occluded, but more importantly, the demineralized dentin collagen matrix was remineralized. Moreover, after mineralization for 24 h, a dense mineral layer similar to enamel structure was regenerated on the surface of dentin and closely combined with dentin. The results of mechanical properties and acid resistance suggested that the mechanical properties of the regenerated enamel-like structure are close to that of enamel, and its acid resistance is better than that of enamel. This study demonstrated that the PDA-assisted co-deposition of PAA can offer an inexpensive, rapid, and efficient strategy for the management of illnesses related to exposed and demineralized dentin. 相似文献
16.
Ultra-high molecular weight polyethylene/iron composites were investigated. The specimens were obtained by pressing in a steel die and sintering at different temperatures. By means of porosimetry, microscopy, microhardness, density, and partial volumes of the components it is shown that there are no microcavities. The microhardness does not depend upon the weight % content of the metal in the composites. It also neither depends on the pressure nor the temperature of sintering. For low metal content within the composites, microhardness Mayer equations are linear. For high metal content the dependence is nonlinear. With the increasing of the iron content tensile strength weakly decreases. However, plane-strain compression, dimension steadiness, Vicat softening temperature, and tribometric characteristics of the composites are improved. It is shown that the polymer is a well-dispersive medium. The particles of the components have a good mechanical compatibility. The polymer wets the surface of the iron; this is probably connected with the surface oxidation of the metal particles. 相似文献
17.
T. N. de Campos 《Journal of Radioanalytical and Nuclear Chemistry》2001,249(2):465-468
A radiometric method was applied to assess enamel wear by another enameland by restorative materials. The radioactive enamel was submitted to wearin a machine which allows sliding motion of an antagonistic surface in contactwith the radioactive enamel. The enamel wear was evaluated by measuring thebeta-activity of 32P transferred to water from this irradiatedtooth. Results obtained indicated that dental porcelains cause pronouncedenamel wear when compared with that provoked by another natural enamel orby resin materials. Resin materials caused less enamel wear than another naturalenamel. Vickers microhardness data obtained for antagonistic materials showeda correlation with the wear caused to the enamel. 相似文献
18.
Holobinko A Meier-Augenstein W Kemp HF Prowse T Ford SM 《Rapid communications in mass spectrometry : RCM》2011,25(7):910-916
Stable isotope analysis of biogenic tissues such as tooth enamel and bone mineral has become a well-recognised and increasingly important method for determining the provenance of human remains, and it has been used successfully in bio-archaeological studies as well as forensic investigations. In particular, (18)O and (2)H stable isotope signatures of bone and hair, respectively, are well-established proxies of climate (temperature) and source water and are therefore considered as indicators of geographic life trajectories of animals and humans. While the methodology for (2)H analysis of human hair, fingernails, and bone collagen is currently used to determine human provenance, i.e. geographic origin and identify possible migration patterns, studies involving the analysis of (2)H in tooth enamel appear to be nonexistent in the scientific literature. Ground tooth enamel was analysed by continuous-flow isotope ratio mass spectrometry (IRMS) coupled on-line to a high-temperature conversion elemental analyser (TC/EA). An array of tooth enamel samples from archaeological and modern teeth has been analysed under different experimental conditions, and the results of this proof-of-concept study are presented. While no significant differences in (2)H abundance were noted as a result of H exchange studies or different sample preparation protocols, no significant differences or trends in measured δ(2)H-values were observed either with regard to known differences in geographical provenance. We concluded that the δ(2)H-values obtained from tooth enamel could not be used as proxy for a person's geographical origin during adolescence. 相似文献
19.
龋病人牙釉质表面硬度及抗磨损性能测试 总被引:1,自引:0,他引:1
采用人工方法制成人牙釉质浅龋及使用抗龋措施的龋损釉质样本,分别测量各组釉质表面显微硬度,并以微动摩擦磨损试验机测试其抗磨性能,试验结果表明:各组实验组釉质较对照组表面硬度都有不同程度下降,氟化钠前处理会使釉质表达硬度显著下降,人工浅龋牙釉质的抗磨损性能不如正常釉质,使用两种抗龋措施对其抗磨性能没有明显改善。 相似文献
20.
Passey BH Cerling TE Levin NE 《Rapid communications in mass spectrometry : RCM》2007,21(17):2853-2859
The oxygen isotope ratio of CO(2) liberated from structural carbonate in tooth enamel apatite was measured at phosphoric acid reaction temperatures of 25 degrees C, 60 degrees C and 90 degrees C, and it was found that apparent acid fractionation factors for pristine enamel, fossilized enamel, and calcite follow different temperature relationships. Using sealed vessel reactions normalized to alpha(25) = 1.01025 (the fractionation factor for calcite at 25 degrees C), the apparent fractionation factor at 90 degrees C (alpha*(90)) for pristine enamel ranged between 1.00771 and 1.00820, and between 1.00695 and 1.00772 for fossilized enamel. Apparent fractionation factors for common acid bath reactions are similar to those for sealed vessel reactions. A significant correlation exists between alpha*(90) and F(-) content, suggesting that change in the acid fractionation factor may be related to the replacement of OH(-) with F(-) during fossilization of bioapatite. These results have important implications for making accurate comparisons between modern and fossil tooth enamel delta(18)O values, and for the uniformity of isotope data produced in different laboratories using different acid reaction temperatures. 相似文献