Addition Of NaF Research Articles

Density of lithium fluoride–lithium carbonate-based molten salts

AbstractThe density of the LiF-Li

The Control of Nanotube Morphology Using Various Factors for Dental Implant.

The purpose of this study was to investigate the control of nanotube morphology using various factors for dental implant. TiO2 nanotube formation on biomedical grade α+β type Ti-6Al-4V alloy was investigated using anodization technique as a function of applied DC potential (10 V to 30 V and 30 V to 10 V) and anodization time for 60 min in 1 M H3PO4 with small additions of NaF (0.5 wt.%, and 0.8 wt.%). The microstructure and phase characteristics of surface were examined by optical microscopy, field emission scanning electron microscopy and X-ray diffraction. Also, in order to observe the biocompatibility and surface roughness, wettability and atomic force microscopy of alloy was measured.

The Effect of Reaction Parameters on the Structural NaYF<sub>4</sub> Microcrystals

NaYF4 microcrystals were synthesized using a hydrothermal method, and the effects of the EDTA and NaF addition amount on the crystal structure, morphology and size were systematically studied. When the NaF addition amount increase, the size of the NaYF4 microcrystal increase, the excess F- ions promote the formation of β-phase of NaYF4. EDTA significantly modifies the morphology of the crystals. When addition the EDTA the crystals transition from irregular silkworm-like microcrystal to hexagonal microprisms. And the EDTA also promote the hexagonal phase formation.

Characterization and dielectric properties of sodium fluoride doped talc

AbstractThe purpose of this paper is to determine the effect of NaF and firing temperature on the dielectric properties (dielectric constant and dielectric loss) of talc, which is used in the electrical and electronic industries as a circuit element. A detailed characterization of the samples was made by XRD, FTIR, SEM and TG-DTG methods. Dielectric measurements were performed in the frequency range from 1 MHz to 80 MHz at room temperature. The dielectric constant value increased with an increase in firing temperature due to the removal of polarizable compounds from the talc structure. The higher dielectric constant values were obtained by addition of NaF. The dielectric loss of NaF doped talc decreased with the increase of firing temperature and increased with the increase of the amount of NaF.

A new perspective on metals and other contaminants in fluoridation chemicals.

Fluoride additives contain metal contaminants that must be diluted to meet drinking water regulations. However, each raw additive batch supplied to water facilities does not come labeled with concentrations per contaminant. This omission distorts exposure profiles and the risks associated with accidents and routine use. This study provides an independent determination of the metal content of raw fluoride products. Metal concentrations were analyzed in three hydrofluorosilicic acid (HFS) and four sodium fluoride (NaF) samples using inductively coupled plasma-atomic emission spectrometry. Arsenic levels were confirmed using graphite furnace atomic absorption analysis. Results show that metal content varies with batch, and all HFS samples contained arsenic (4·9-56·0 ppm) or arsenic in addition to lead (10·3 ppm). Two NaF samples contained barium (13·3-18·0 ppm) instead. All HFS (212-415 ppm) and NaF (3312-3630 ppm) additives contained a surprising amount of aluminum. Such contaminant content creates a regulatory blind spot that jeopardizes any safe use of fluoride additives.

Corrosion behaviour of Ti6Al4V alloy in artificial saliva solution with fluoride content and low pH value

The corrosion resistance of the Ti6Al4V alloy in Carter–Brugirard artificial saliva (pH = 5.2), in saliva with sodium fluoride (NaF) addition (pH = 5.2) and in saliva with NaF and lactic acid (pH = 2.0) was evaluated. The open circuit potential of the alloy in all electrolytes was stable after approximately 2 h of immersion. Higher corrosion rate and lower polarization resistance were measured for the alloy immersed in fluoridated saliva, compared to genuine saliva, indicating that the addition of NaF lead to a worse corrosion resistance. In fluoridated and acidified saliva (pH = 2), the Ti6Al4V alloy exhibited the lowest corrosion resistance. The corroded surfaces are much rougher than those non-corroded. A higher roughness was obtained for the alloy immersed in saliva with NaF and low pH, indicating that the corrosion process was more active in this electrolyte. Large precipitates of corrosion products and corrosive sites were found on the samples immersed in all electrolytes.

Viscosity Measurement of SiO2–Na2O Melts with Addition of NaF

Viscosity Measurement of SiO2–Na2O Melts with Addition of NaF

Combinatorial study of NaF addition in CIGSe films for high efficiency solar cells

AbstractWe report on a sodium fluoride (NaF) thickness variation study for the H2Se batch furnace selenization of sputtered Cu(In,Ga) films in a wide range of Cu(In,Ga) film compositions to form Cu(In,Ga)Se2 (CIGSe) films and solar cells. Literature review indicates lack of consensus on the mechanisms involved in Na altering CIGSe film properties. In this work, for sputtered and batch‐selenized CIGSe, NaF addition results in reduced gallium content and an increase in grain size for the top portion of the CIGSe film, as observed by scanning electron microscopy and secondary ion mass spectrometry. The addition of up to 20 nm of NaF resulted in an improvement in all relevant device parameters: open‐circuit voltage, short‐circuit current, and fill factor. The best results were found for 15 nm NaF addition, resulting in solar cells with 16.0% active‐area efficiency (without anti‐reflective coating) at open‐circuit voltage (VOC) of 674 mV. Copyright © 2013 John Wiley & Sons, Ltd.

Refractive index modification in fluoro-borate glasses containing WO3 induced by femtosecond laser

New glasses belonging to the NaF–Na2B4O7–WO3 system have been studied in order to inscribe optical waveguides within their volume through local refractive index modification after irradiation by ultrafast laser pulses. Appropriate addition of NaF to glasses belonging to the pseudo-binary vitreous system Na2B4O7–WO3 has allowed to obtain striae-free bulk glasses of large volume with high content of WO3 (35mol%). Their physical and structural properties have been investigated through UV–visible spectroscopy, differential scanning calorimetry, densitometry and Raman spectroscopy. The glass of composition (NaF)15–(Na2B4O7)50–(WO3)35 has been then exposed to 800nm femtosecond pulses of 70fs width at a repetition rate of 100kHz from a Ti-sapphire regenerative amplifier system. By varying the input pulse energy and scanning speed, homogeneous optical waveguides were inscribed and a positive refractive index change of the order of 5×10−3 has been measured.

Stability of morphine, codeine, and 6-acetylmorphine in blood at different sampling and storage conditions.

The stability of drugs in biological specimens is a major concern during the evaluation of the toxicological results. The stability of morphine, codeine, and 6-acetyl-morphine in blood was studied after different sampling conditions: (i) in glass, polypropylene or polystyrene tubes, (ii) with addition of dipotassium ethylene diamine tetraacetic acid (K2EDTA) or sodium oxalate (Na2C2O4), and (iii) with or without the addition of sodium fluoride (NaF). Spiked blood samples were stored at two different temperatures (4 and -20°C), analyzed after different storage times and after three freeze–thaw cycles. Opiate concentrations were decreased in all conditions, but the most unstable was 6-acetyl-morphine. The addition of NaF as preservative improved the stability of opiates at all conditions studied, whereas the type of anticoagulant did not affect the stability of opiates. It was concluded that blood samples should be stored at -20°C in glass tubes containing oxalate and NaF for maximum stability.

Effect of the pH on the formation of NaYF4:Yb:Er nanopowders by co-crystallization in presence of polyethyleneimine

Study of nanopowder precipitation from aqueous sodium fluoride and yttrium and/or other rare earth nitrate solutions in the presence of polyethyleneimine (PEI) has revealed the strong dependence of the solid phase composition upon the solutions’ pH values and the order of reagent addition. The conditions for single phase formation have been determined for both cubic and hexagonal NaYF4-type phases. Cubic single-phase samples were obtained by adding rare earth element nitrate solutions to aqueous NaF–PEI mixtures at pH=10; while hexagonal single-phase precipitates were synthesized by the addition of aqueous NaF to aqueous rare earth element nitrate solutions+PEI mixtures at pH=12.

Sodium Fluoride Inhibits MMP-2 and MMP-9

The importance of fluoride (F) in preventing dental caries by favorably interfering in the demineralization-remineralization processes is well-established, but its ability to inhibit matrix metalloproteinases (MMPs), which could also help to prevent dentin caries, has not been investigated. This study assessed the ability of F to inhibit salivary and purified human gelatinases MMPs-2 and -9. Saliva was collected from 10 healthy individuals. Pooled saliva was centrifuged, and supernatants were incubated for 1 hr at 37°C and subjected to zymography. Sodium fluoride (50-275 ppm F) was added to the incubation buffer. The reversibility of the inhibition of MMPs-2 and -9 by NaF was tested by the addition of NaF (250-5,000 ppm F) to the incubation buffer, after which an additional incubation was performed in the absence of F. F decreased the activities of pro- and active forms of salivary and purified human MMPs in a dose-response manner. Purified gelatinases were completely inhibited by 200 ppm F (IC50 = 100 and 75 ppm F for MMPs-2 and -9, respectively), and salivary MMP-9 by 275 ppm F (IC50 = 200 ppm F). Inhibition was partially reversible at 250-1,500 ppm F, but was irreversible at 5,000 ppm F. This is the first study to describe the ability of NaF to inhibit MMPs completely.

Wavelength-tunable absorption and luminescence of SiO2–Al2O3–ZnO–Na2O–K2O–NaF glasses with PbS quantum dots

Lead sulfide quantum dots (QDs) with average diameter of 3.0–6.5nm were grown in novel SiO2–Al2O3–ZnO–Na2O–K2O–NaF glasses highly-doped with PbO and elemental sulfur by means of single-stage heat-treatment at temperatures slightly lower the vitrification point. Introduction of two alkaline components to the glass system allows us to perform the synthesis without control of sulfur evaporation, while stabilization of PbS crystal nuclei was provided by addition of NaF. Optical absorption and photoluminescence of these PbS-QD-doped glasses were studied in dependence on treatment temperature (480–520°C) and duration (5–130h). The growth rate of QDs was substantially enhanced with the increase of treatment temperature. The position of 1S–1S excitonic absorption peak was tuned from 0.75 to 1.6μm, accompanied by management of peak absorption within 7–45cm−1 range. Intense Gaussian-shaped photoluminescence associated with radiative exciton recombination from 1S–1S state was observed in 1.1–1.6μm spectral range.

Surface Roughness Changes on β-Titanium Orthodontic Wires after Corrosion in Various Artificial Saliva Solutions

Abstract β-Titanium orthodontic wires are exposed to three different artificial corrosive environments, modified Fusayama, modified Fusayama with 0.1 % NaF addition, and modified Fusayama with 1.7 % H3PO4 addition, which are similar to the oral cavity conditions. Corrosion behaviours of wires are observed by using weight loss method and scanning electron microscope observations. Afterwards, surface roughness of wires is investigated in details. Consequently, it is determined that corrosion rate of β-titanium wires exposed to the modified Fusayama solutions with H3PO4 addition is higher because of the acidity of this saliva. Furthermore, maximum increase in surface roughness and skewness are observed in the same environment. Hydrogen embrittlement of titanium is also an important factor for the corrosion of wires.

Analysis of boron in fluid inclusions by microthermometry, laser ablation ICP-MS, and Raman spectroscopy: Application to the Cryo-Genie Pegmatite, San Diego County, California, USA

Boron contents in magmatic fluids are largely unknown, even though B is an important constituent in granitic magmas and, potentially, in ore fluids. Owing to the fact that fluid inclusions from Li-rich pegmatites are typically B, Li, and Na±F-rich aqueous solutions, salinity derived from microthermometry via the freezing point depression (NaCleq) may be inaccurate. In this study, the ratio of the integrated areas of the Raman bands of [B(OH)3]aq0 at ~878cm−1 (B[3]O stretching) and of H2O at ~3400cm−1 (OH stretching) were used for quantitative analysis of B concentrations in fluid inclusions in quartz. Then, B concentration measured via Raman spectroscopy was used as an internal standard for LA-ICP-MS analysis instead of using Na contents derived from NaCleq obtained by microthermometry. This study revisits, validates, and optimizes the methodology for analysis of boron in fluid inclusions from granitic pegmatites and from other boron-rich environments by combining results from Raman spectroscopy, LA-ICP-MS and microthermometry.Raman analyses of synthetic solutions that approximate the composition of pegmatitic fluid inclusions were used to evaluate the effects of NaCl (1.1–12mass%), LiCl (1.5–16), Li2CO3 (0.05–0.6), NaF (0.6–1.7), and LiF (0.006–0.06) on H3BO3 solutions ranging from 0.28 to 2.0mass% of H3BO3 for the analysis of H3BO3 by Raman spectroscopy. The errors in H3BO3 concentration induced by NaCl, LiCl, and LiF, the most common salts in pegmatitic fluids, were all ≤±6%. Addition of Li2CO3 in excess of ~0.1 Li2CO3/H3BO3 ratio and addition of NaF in excess of ~0.2 NaF/H3BO3 ratio caused a systematic decrease in the intensity of the νsB[3]O band at ~878cm−1 (I878) that resulted in the B concentration being underestimated by as much as 80%. This is related to an increase of solution pH that decreases the stability of [B(OH)3]aq0. The effect of the inclusion-host quartz lattice orientation on the Raman signal was also tested. When the sample is cut perpendicular to the quartz c-axis or if its c-axis is co-planar with the laser polarization plane, the lattice effects on borate calibration become negligible.

Stabilization of zeylenone in rat plasma by the presence of esterase inhibitors and its LC‐MS/MS assay for pharmacokinetic study

Six esterase inhibitors, namely EDTA·2Na(+), NaF, phenylmethanesulfonyl fluoride, dichlorvos, bis-nitrophenyl phosphate (BNPP) and thenoyltrifluoroacetone, and the mixture of NaF and BNPP, were evaluated for the stabilization of labile benzoate containing zeylenone in rat plasma. The mixture appeared to exhibit the most effectively stabilizing effect with the degraded content of zeylenone decreasing from >60% (in the absence of inhibitors) to <6%. Following the stabilization by the addition of NaF (5 mM) and BNPP (5 mM), the analytes in rat plasma were acidified by formic acid and extracted into ethyl acetate at 0°C. After chromatographic separation, the detection of zeylenone was performed on a 3200 Q-Trap with positive ion electrospray mode, monitoring the ion transition m/z 383.2 → 105.0. The method was validated over the range from 2.68 to 1340 ng/mL with inter- and intra-run precision for the quality control samples being less than 6.8%. The assay accuracy was within 100 ± 7.0%. The validated method was successfully applied to a pharmacokinetic study in rats after the intratracheal administration of zeylenone in free drug or polymeric micellar solutions. The results showed that the pulmonary absorption of zeylenone loaded in micelles was significantly retarded compared with that of free drug solutions.

Ti–Ge binary alloy system developed as potential dental materials

As-cast Ti-xGe (x = 2, 5, 10, 20 wt %) binary alloys were produced in this work, and various experiments were carried out to investigate the microstructure, mechanical properties, in vitro electrochemical and immersion corrosion behaviors as well as cytotoxicity with as-cast pure Ti as control, aiming to study the feasibility of Ti-xGe alloy system as potential dental materials. The microstructure of Ti-xGe alloys changes from single α-Ti phase to α-Ti + Ti(5)Ge(3) precipitation phase with the increase of Ge content. Mechanical tests show that Ti-5Ge alloy has the best comprehensive mechanical properties. The corrosion behavior of Ti-xGe alloys in artificial saliva with different NaF and lactic acid addition at 37°C indicates that Ti-2Ge and Ti-5Ge alloys show better corrosion resistance to fluorine-containing solution. The cytotoxicity test indicates that Ti-xGe alloy extracts show no obvious reduction of cell viability to L-929 fibroblasts and MG-63 osteosarcoma cells, similar to pure Ti which is generally acknowledged to be biocompatible. Considering all these results, Ti-2Ge and Ti-5Ge alloys possess the optimal comprehensive performance and might be used as potential dental materials.

Effect of NaF flux on microstructure and thermoluminescence properties of Sm3+ doped CdSiO3 nanophosphor

This work reports the preparation of CdSiO3:Sm3+ (1–7mol%) nanophosphors by a low temperature solution combustion method. For the first time the effect of NaF flux on the crystallization behavior, morphology, and thermoluminescence property of 5mol% Sm3+ doped CdSiO3 has been investigated. The nanopowders are well characterized by powder X-ray diffraction (PXRD), Fourier Transform Infra-Red (FT–IR), and scanning electron microscopy (SEM). PXRD results indicate that the powder calcined at 800°C for 2h has monoclinic phase. SEM results show that the powder is highly porous and the pore size and shape can be modified by the addition of NaF flux. Addition of NaF could lead to formation of particle type morphology and the increase in wt% of NaF changes crystallinity and phase. The thermoluminescence glow curves for 2–6wt% NaF in CdSiO3:Sm3+ show a single, well resolved glow peak at 126, 130 and 150°C, respectively. But for the sample prepared with 8wt% of NaF flux shows two glow peaks at 148 and 220°C. With the addition of NaF flux, TL intensity can be effectively enhanced.

Influence of NaF on Crystallization and Machinability of Mica Glass Ceramics

Effect of NaF on crystallization kinetics, microstructure, and mechanical properties of mica glass ceramics were investigated by the differential thermal analysis (DTA), X-ray diffractometry (XRD), scanning electron microscopy (SEM), and microhardness tests. Non-isothermal DTA experiments showed that the crystallization activation energies of base glasses are changed in the range of 235–246 KJ/mol, while the crystallization activation energies of samples with addition of NaF are changed in the range of 263–367 KJ/mol. The increase of crystallization temperature is helpful for the increase of aspect ratio, and the microstructure of the glass ceramics becomes interconnected, which contributes the improvement of the machinability of the glass ceramics. Microhardness (Hv), cutting energy (μ1), and machinability parameter (m) can be used for estimating the machinability of mica glass ceramics. Transparency in the studied glass samples is assumed to occur due to the presence of crystallites with nano size.

Comparison of Retention of Provisional Crowns Cemented with Temporary Cements Containing Stannous Fluoride and Sodium Fluoride—An In Vitro Study

The objective of this study was to evaluate the effect of the addition of stannous fluoride (SnF2) and sodium fluoride (NaF) to luting cements on the retention of provisional crowns. Provisional crowns were fabricated using methyl methacrylate and bis-acryl composite resin for 32 chamfer prepared molars. For control group A, crowns were cemented with Freegenol and RelyX Temp NE non-eugenol cements. For test group B, crowns were cemented using the above cements with the addition of SnF2. For test group C, crowns were cemented using the above cements with the addition of NaF. The specimens were thermocycled and retention test was conducted after 7days. The addition of SnF2 significantly increased the retentive strength of both the cements in the range of 27-48%, whereas addition of NaF decreased the retentive strength of both the cements in the range of 14-23%. SnF2 can be mixed with non-eugenol luting cements to improve the retention of both methyl methacrylate and bis-acryl composite crowns. The different effects of NaF and SnF2 on retention indicate that it may be useful to have two different types of provisional luting cements for short-term and long-term cementation, as appropriate.