Aspects of Quantitative Determination by Ion Probe of Fluorine Concentrations in Apatites

1974 ◽  
Vol 29 (6) ◽  
pp. 897-900 ◽  
Author(s):  
A. Lodding ◽  
J.-M. Gourgout ◽  
L. G. Petersson ◽  
G. Frostell
Keyword(s):  
Quantitative Determination ◽  
Simultaneous Recording ◽  
Ion Currents ◽  
Experimental Conditions ◽  
Apatite Crystals ◽  
Ion Probe ◽  
Human Enamel ◽  
Micro Analysis ◽  
Secondary Ion ◽  
Probe Measurements

In studies of F concentrations in apatite crystals by means of secondary ion micro-analysis, it is found that even in a sample with a known and constant F/Ca ratio the recorded ratios of the F and Ca secondary ion currents can vary widely, depending on the experimental conditions of primary bombardment. An attempt has been to explain this behaviour and to devise a way to obtain quantitative atomic F to Ca ratios independent on measuring conditions. Simultaneous recording of the mass peaks of F+, Ca+ and another matrix ion (P+ or C++) appears to offer a solution of the reproducibility problem. This is demonstrated by ion probe measurements under varied conditions in three groups of materials where the F concentrations had previously been determined by macroscopic methods: apatite crystals with about 3% F, whale teeth of about 10-1 % F, and human enamel ob about 10-2 % F.

Ion Probe Study of Fluorine Gradients in Outermost Layers of Human Enamel

1976 ◽  
Vol 55 (6) ◽  
pp. 980-990 ◽  
Author(s):  
L.G. Petersson ◽  
H. Odelius ◽  
A. Lodding ◽  
S.J. Larsson ◽  
G. Frostell
Keyword(s):  
Tooth Enamel ◽  
Human Tooth ◽  
Concentration Profiles ◽  
Human Tooth Enamel ◽  
Fluoride Treatment ◽  
Ion Probe ◽  
Human Enamel ◽  
Reference Specimens ◽  
Topical Fluoride ◽  
Secondary Ion

F concentrations in the outermost layers of human tooth enamel were studied with the aid of a secondary ion microanalyzer. Concentration profiles were recorded in continuous sputtering analysis from the surface down to a depth of about 0.3 micrometer. Samples previously subjected to topical fluoride treatment were compared with reference specimens. In some samples, the results were compared with those obtained at greater depths by macrascopic etching analysis.

Trace element distributions in meteorites determined by ion probe analysis

1981 ◽  
Vol 374 (1757) ◽  
pp. 195-205 ◽  
Keyword(s):  
Trace Element ◽  
Trace Element Analysis ◽  
Diffusion Profile ◽  
Element Analysis ◽  
Ni Content ◽  
Probe Analysis ◽  
Ion Probe ◽  
Small Grains ◽  
Secondary Ion ◽  
Probe Measurements

The ion probe is particularly suitable for localized trace element analysis, owing to the very low background in the secondary ion mass spectrum. It is therefore worth exploring the possibilities of the technique in relation to trace element distributions in meteorites, in cases where the sensitivity of the electron probe is inadequate. Ion probe measurements of Ni in olivine in pallasites show concentrations in the range 20-35 µg g- 1 and a diffusion profile in Eagle Station olivine grains has been observed, the central Ni content being higher than that at the edge. In Glorieta Mountain the opposite trend is seen and there is an inverse grain-size correlation (small grains having the highest Ni content) indicating a different thermal history. The trace element Ga, which is important in connection with iron meteorite classification, is well suited to ion probe analysis and is found to be strongly concentrated in taenite in both iron meteorites and chondrites.

The Effect of Lesion Characteristic on Remineralization and Model Sensitivity

1992 ◽  
Vol 71 (3_suppl) ◽  
pp. 811-813 ◽  
Author(s):  
F. Schäfer ◽  
S.J. Raven ◽  
T.A. Parr
Keyword(s):  
Real Life ◽  
High Sensitivity ◽  
Lesion Size ◽  
Experimental Conditions ◽  
Treatment Groups ◽  
Human Enamel ◽  
Enamel Sample ◽  
Two Factors ◽  
Treatment Bias

A major criterion for assessing the value of any experimental model in scientific research is the degree of correspondence between its results and data from the real-life process it is designed to model. Intra-oral models aimed at predicting the anti-caries efficacy of toothpastes or other topical treatments should therefore be calibrated against treatments proven to be effective in a caries clinical trial. For this to be achieved, it is necessary that a model with high sensitivity be designed, while at the same time retaining relevance to the process to be modeled. This means that the effects of the various experimental conditions and parameters of the model on its performance must be understood. The purpose of this paper was to assess the influence of two specific factors on the performance of an in situ enamel remineralization model, which is based on human enamel slabs attached to partial dentures. The two factors are initial lesion severity and origin of enamel sample. The results indicated that initial lesion size affected whether net remineralization or net demineralization occurred during in situ treatment. Samples with an initial range of from 1500 to 2500 (ΔZ) tended more toward demineralization than did samples with ΔZ > 3500. This means that treatment groups must be well-balanced with respect to initial lesion size. Differences in initial demineralization severity between different tooth locations must also be considered so that systematic treatment bias can be avoided. The solution used in the model discussed here is based on a balanced experimental design, which allows this effect to be taken into account in the data analysis.

Remineralization Potential of a New Toothpaste Formulation: An In-Vitro Study

2004 ◽  
Vol 5 (1) ◽  
pp. 18-30 ◽  
Author(s):  
Carlos A. Muñoz ◽  
Anna Torrado ◽  
Manuel Valiente ◽  
Wu Zhang ◽  
Yiming Li
Keyword(s):  
Ion Exchange ◽  
In Vitro Study ◽  
Ion Exchange Resin ◽  
Ion Exchange Resins ◽  
Experimental Conditions ◽  
Human Enamel ◽  
Before And After ◽  
Ph Cycling ◽  
Exchange Resins

Abstract The aim of the present study was to determine the ability of a dentifrice containing a mixture of ion-exchange resins (named NMTD), which supplies calcium, fluoride, phosphate, and zinc ions, to promote remineralization and/or inhibit demineralization of dental human enamel in a pH cycling model in vitro. A fluoride toothpaste was used as the control. The enamel specimens were tested for microhardness before and after 10 days and 16 days of the demineralizing and remineralizing treatments. The results of this study showed both dentifrices were effective in limiting in vitro enamel demineralization although the effects were not significantly different from each other. Inclusion of calcium and phosphate ion-exchange resins in the dentifrice containing a fluoride ion-exchange resin maintained a similar net outcome of the conventional dentifrice in the demineralization/ remineralization process under the experimental conditions employed. Citation Torrado A, Valiente M, Zhang W, et. al. Remineralization Potential of a New Toothpaste Formulation: An In-Vitro Study. J Contemp Dent Pract 2004 February;(5)1:018-030.

2-(2'- Chloro Phenyl)- 5- (2'-Hydroxyl Phenyl)-1,3,4-Oxadiazole as a Florescent Probe for DNA Determination

2011 ◽  
Vol 301-303 ◽  
pp. 361-365
Author(s):  
Mei Ding ◽  
Ying Jie Lei ◽  
Ou Yang Jie
Keyword(s):  
Experimental Data ◽  
Fluorescence Quenching ◽  
Quantitative Determination ◽  
Fluorescent Probe ◽  
Fluorescence Intensity ◽  
Dna Analysis ◽  
Fluorescence Spectrometry ◽  
Experimental Conditions ◽  
Convenient Synthesis

In recent years, fluorescence spectrometry was widely used in quantitative determination of DNA. In this paper, a convenient synthesis of a new fluorescent 2-(2'- Chloro phenyl)- 5- (2'- hydroxyl phenyl)-1,3,4-oxadiazole (HOXD) was realized. Experimental data showed that fluorescence of HOXD could be quenched by DNA and the decreased fluorescence intensity of HOXD resulting from fluorescence quenching is proportional to DNA concentrations suggesting that HOXD could be used as a new fluorescent probe for quantitative determination of DNA. Optimal experimental conditions for DNA analysis were also studied in the paper.

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