Preparation of bromine fluoride

International Nuclear Information System (INIS)

Domange, Pr; Duflo, J.

1958-05-01

This note addresses the preparation of bromine fluoride. It indicates the implemented process for the reaction, used products (fluorine and bromine), and column characteristics. It describes the operating mode. Apparatus drawing is provided

21 CFR 582.3845 - Stannous chloride.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Stannous chloride. 582.3845 Section 582.3845 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL....3845 Stannous chloride. (a) Product. Stannous chloride. (b) Tolerance. This substance is generally...

21 CFR 172.180 - Stannous chloride.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Stannous chloride. 172.180 Section 172.180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Preservatives § 172.180 Stannous chloride. The food additive stannous chloride may be safely used for color...

“Self-Peel-Off” Transfer Produces Ultrathin Polyvinylidene-Fluoride-Based Flexible Nanodevices

KAUST Repository

Tai, Yanlong; Lubineau, Gilles

2017-01-01

Here, a new strategy, self-peel-off transfer, for the preparation of ultrathin flexible nanodevices made from polyvinylidene-fluoride (PVDF) is reported. In this process, a functional pattern of nanoparticles is transferred via peeling from a

Preparation of bromine fluoride; Preparation du fluorure de brome

Energy Technology Data Exchange (ETDEWEB)

Domange, Pr; Duflo, J.

1958-05-15

This note addresses the preparation of bromine fluoride. It indicates the implemented process for the reaction, used products (fluorine and bromine), and column characteristics. It describes the operating mode. Apparatus drawing is provided.

PREPARATION AND CHARACTERIZATION OF STRONTIUM FLUORIDE POWDERS ACTIVATED BY NEODYMIUM FLUORIDE

Directory of Open Access Journals (Sweden)

S. V. Kuznetsov

2015-07-01

Full Text Available Subject of Study. The paper deals with preparation processes of ultradisperse, homogeneous powder Sr1-хNdхF2+х (х= 0.003-0.2, with use of ammonium fluoride as the fluorinating agent taken over 114-120 % from stoichiometry. Method. Nitrate of strontium, neodymium nitrate hexahydrate, with the content equal to 99. 99 % of the basic substance and ammonium fluoride were used as the source of substances. Activated powders of strontium fluoride were obtained by the method of deposition from aqueous solutions by washing the precipitate with a solution of ammonium fluoride, taken over 114 - 120% from stoichiometry. The washed precipitate was centrifuged for 5-7 min, dried in the air at 30-350 C. Heat treatment of the dried precipitate was carried out in two stages: the first stage at the temperature of 200- 2500 C for 0.5-1 hour, the second one at 550- 6000 C for 2-3 hours. X-ray analysis of the synthesized samples was carried out on a Bruker D8 Advance diffractometer, radiation Cu K. The size and shape measuring of the particles of activated strontium fluoride was carried out by means of electron microscope Carl Zeiss NVision 40. The content of neodymium in activated powders of strontium fluoride was determined by the method of spectral emission analysis on the device LEA - S500. Chemical analysis for determination of ammonium ion (NH4+ content in the obtained samples was performed by the method of Kjeldahl. Calculations of lattice parameters, size of coherent scattering regions and the values of micro-deformations were carried out by TOPAS program. Main Results. Preparation processes of ultradisperse, homogeneous powder Sr1-хNdхF2+х (х= 0.003-0.2, with use of ammonium fluoride as the fluorinating agent taken over 114-120 % from stoichiometry, provides obtaining the firm solution Sr1-x-yNdx(NH4yF2+x-y of the cubic fluorite structure. It has been found out that the morphology and size of the resulting product depend on the quantity of

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

Treatment of dentin with stannous fluoride - SEM and electron microprobe study

International Nuclear Information System (INIS)

Ellingsen, J.E.; Roella, G.

1987-01-01

The effect of SnF 2 -treatment of dentin surfaces was investigated by means of scanning electron microscopy (SEM) and electron microprobe analysis. Human dentin was treated with aqueous SnF 2 solutions of concentrations varying from 1 to 10%. The treatment periods lasted for 1, 5, 10 or 60 min. Both tin and fluoride were identified on the surfaces. The concentration varied depending on the extensiveness of the treatment. Immersion in 1 M KOH for 15 h removed both tin and fluoride from the surfaces. This reaction was not observed after immersion in H 2 O for the same time period. Examination of the SnF 2 -treated dentin surfaces showed a dense layer of globular particles and in addition some larger particles. The dentinal tubules were totally covered even after the treatment with the lowest concentration of SnF 2 . Deposition of tin- and fluoride-containing globules on dentin surfaces may be of clinical interest. This layer may have importance both for the caries resistance of dentin and for hypersensitivity reactions. (author)

Clinical evaluation of the intraoral fluoride releasing system in radiation-induced xerostomic subjects. Part 2: Phase I study.

Science.gov (United States)

Chambers, Mark S; Mellberg, James R; Keene, Harris J; Bouwsma, Otis J; Garden, Adam S; Sipos, Tibor; Fleming, Terence J

2006-10-01

Radiation-induced xerostomia can result in the rapid onset and progression of dental caries in head and neck cancer patients. Topically applied fluorides have been successfully used to inhibit the formation of dental caries in this population. However, because intensive daily self-application is required, compliance is an issue. The intraoral fluoride-releasing system (IFRS) containing a sodium fluoride core is a newly developed, sustained-release, passive drug delivery system that does not require patient involvement except for periodic replacement, thus reducing the effect of patient compliance on its effectiveness in dental caries prevention. Twenty-two head and neck cancer patients from U. T. M. D. Anderson Cancer Center, with radiation-induced xerostomia, were entered into a pilot study to contrast the daily home use of a 0.4% stannous fluoride-gel-containing tray (control group) to IFRS (study group) with respect to tolerability and adherence, and to obtain information on relative caries preventive efficacy. Participants were stratified on the basis of radiation exposure and randomly assigned to treatment with either IFRS or stannous fluoride gel. Patients in both groups were fitted with two IFRS retainers and also were instructed to use a 1100-ppm fluoride conventional sodium fluoride dentifrice twice daily. The study was conducted as a single-blinded, parallel-cell trial. Pre-existing carious lesions were restored prior to the beginning of the study. The efficacy variable was determined by the mean number of new or recurrent decayed surfaces. Patients were examined for caries 4, 8, 12, 24, 36, and 48 weeks after initiation of treatment. Reports of adverse reactions were based on information volunteered by patients and that were elicited during interviews. At baseline, the resting and stimulated salivary flow rates (g/5min) were significantly greater in the control group than in the study group (pIFRS groups during the study period. The rate of new or

Preparation of lithium fluoride for thermoluminescent detectors of ionizing radiation

Energy Technology Data Exchange (ETDEWEB)

Mironenko, S.N.; Nepomnyashchikh, A.I.; Ikrami, D.D.; Paramzin, A.S.; Rakhimov, M.Eh.

1985-03-01

The thermostimulated luminescence (TSL) of lithium fluoride monocrystals depending on the method of preparation of starting raw material and features of its preliminary processing is investigated. It is shown that only lithium fluoride of high purity prepared through the stage of formation of hydrofluoride and its subsequent decomposition can be used without any additional processing for manufacturing monocrystal detectors of thermoluminescent dosimetry of the ionizing radiation with low intensity of low temperature peaks.

Erratum to "Clinical evaluation of the intraoral fluoride releasing system in radiation-induced xerostomic subjects. Part 2: Phase I study".

Science.gov (United States)

Chambers, Mark S; Fleming, Terence J; Toth, Béla B; Lemon, James C; Craven, Timothy E; Bouwsma, Otis J; Garden, Adam S; Espeland, Mark A; Keene, Harris J; Martin, Jack W; Sipos, Tibor

2007-01-01

Radiation-induced xerostomia can result in the rapid onset and progression of dental caries in head and neck cancer patients. Topically applied fluorides have been successfully used to inhibit the formation of dental caries in this population. However, because intensive daily self-application is required, compliance is an issue. The intraoral fluoride-releasing system (IFRS) containing a sodium fluoride core is a newly developed, sustained-release, passive drug delivery system that does not require patient involvement except for periodic replacement, thus reducing the effect of patient compliance on its effectiveness in dental caries prevention. Twenty-two head and neck cancer patients from U. T. M. D. Anderson Cancer Center, with radiation-induced xerostomia, were entered into a pilot study to contrast the daily home use of a 0.4% stannous fluoride-gel-containing tray (control group) to IFRS (study group) with respect to tolerability and adherence, and to obtain information on relative caries preventive efficacy. Participants were stratified on the basis of radiation exposure and randomly assigned to treatment with either IFRS or stannous fluoride gel. Patients in both groups were fitted with two IFRS retainers and also were instructed to use a 1100-ppm fluoride conventional sodium fluoride dentifrice twice daily. The study was conducted as a single-blinded, parallel-cell trial. Pre-existing carious lesions were restored prior to the beginning of the study. The efficacy variable was determined by the mean number of new or recurrent decayed surfaces. Patients were examined for caries 4, 8, 12, 24, 36, and 48 weeks after initiation of treatment. Reports of adverse reactions were based on information volunteered by patients and that were elicited during interviews. At baseline, the resting and stimulated salivary flow rates (g/5min) were significantly greater in the control group than in the study group (pIFRS groups during the study period. The rate of new or

The impact of stannous, fluoride ions and its combination on enamel pellicle proteome and dental erosion prevention.

Directory of Open Access Journals (Sweden)

A A Algarni

Full Text Available To compare the effects of stannous (Sn and fluoride (F ions and their combination on acquired enamel pellicle (AEP protein composition (proteome experiment, and protection against dental erosion (functional experiment.In the proteome experiment, bovine enamel specimens were incubated in whole saliva supernatant for 24h for AEP formation. They were randomly assigned to 4 groups (n=10, according to the rinse treatment: Sn (800ppm/6.7mM, SnCl2, F (225ppm/13mM, NaF, Sn and F combination (Sn+F and deionized water (DIW, negative control. The specimens were immersed 3× in the test rinses for 2min, 2h apart. Pellicles were collected, digested, and analyzed for protein content using liquid chromatography electrospray ionization tandem mass spectrometry. In the functional experiment, bovine enamel specimens (n=10 were similarly treated for pellicle formation. Then, they were subjected to a five-day erosion cycling model, consisting of 5min erosive challenges (15.6 mM citric acid, pH 2.6, 6×/d and 2min treatment with the rinses containing Sn, F or Sn+F (3×/d. Between the treatments, all specimens were incubated in whole saliva supernatant. Surface loss was determined by profilometry.Our proteome approach on bovine enamel identified 72 proteins that were common to all groups. AEP of enamel treated with Sn+F demonstrated higher abundance for most of the identified proteins than the other groups. The functional experiment showed reduction of enamel surface loss for Sn+F (89%, Sn (67% and F (42% compared to DIW (all significantly different, p<0.05.This study highlighted that anti-erosion rinses (e.g. Sn+F can modify quantitatively and qualitatively the AEP formed on bovine enamel. Moreover, our study demonstrated a combinatory effect that amplified the anti-erosive protection on tooth surface.

Preparation of uranium ingots from double fluorides

International Nuclear Information System (INIS)

Le Boulbin, E.

1967-05-01

A simple method has been developed for the preparation of uranium double fluorides and has given a new impetus to the study of the reduction of these compounds with a view to obtaining very pure uranium ingots. This reduction can be carried out using calcium or magnesium as the reducing agent, this latter metal being very interesting from the practical point of view. A comparative study of the heat balances of the reduction processes for the double fluorides and for uranium tetrafluoride has shown that reduction of the double fluorides is possible. The exact experimental conditions for these reductions have been determined. Our study has shown in particular that the reduction of the double salt UF 4 , CaF 2 by magnesium leads to the production of small (20 to 500 g) samples of high-purity uranium with a yield of 99 per cent. (author) [fr

Fluoride Increase in Saliva and Dental Biofilm due to a Meal Prepared with Fluoridated Water or Salt: A Crossover Clinical Study.

Science.gov (United States)

Lima, Carolina V; Tenuta, Livia M A; Cury, Jaime A

2018-06-07

Knowledge about fluoride delivery to oral fluids from foods cooked with fluoridated water and salt is scarce, and no study has evaluated fluoride concentrations in saliva or biofilm during meal consumption. In this randomized double-blind crossover study, 12 volunteers ingested meals (rice, beans, meat, and legumes) prepared with nonfluoridated water and salt (control group), fluoridated water (0.70 mg F/L; water group), and fluoridated salt (183.7 mg F/kg; salt group). Whole saliva was collected before meal ingestion, during mastication, and up to 2 h after meal ingestion. Dental biofilm was collected before and immediately after meal ingestion. Fluoride concentrations in saliva and dental biofilm were determined by an ion-specific electrode. The mean (±standard deviation; n = 4) fluoride concentrations in meals prepared for the control, water, and salt groups were 0.039 ± 0.01, 0.43 ± 0.04, and 1.71 ± 0.32 μg F/g, respectively. The three groups had significantly different fluoride concentrations in saliva collected during mastication (p water > control). The fluoride concentration in saliva returned to baseline 30 min after meal ingestion in the water group but remained high for up to 2 h in the salt group (p = 0.002). The fluoride concentration in biofilm fluid differed only between the salt and control groups (p = 0.008). The mastication of foods cooked with fluoridated water and salt increases fluoride concentrations in oral fluids and may contribute to the local effect of these community-based fluoride interventions on caries control. © 2018 S. Karger AG, Basel.

Protection From Dental Erosion: All Fluorides are Not Equal.

Science.gov (United States)

Faller, Robert V; Noble, Warden H

2018-03-01

All fluoride sources help strengthen teeth against bacterial acids that cause caries. However, excessive exposure to dietary acids, which can result in dental erosion, presents a more aggressive level of challenge compared to caries. Despite the fact that almost all toothpastes contain fluoride, both the incidence and prevalence of dental erosion appear to be on the rise. This article: (1) describes key differences between caries and dental erosion and the ability of different fluoride sources to help prevent erosion; (2) discusses the importance of the evaluation of patients for dental erosion at the earliest stages using the Basic Erosive Wear Examination scoring system to help assess and educate patients; and (3) provides evidence-based information for making specific recommendations to patients with dental erosion. The objective of this article is to assess the comparative ability of fluoride agents to protect against dental erosion. Though all fluorides are able to help strengthen teeth against cariogenic acids, not all available sources of fluoride provide the same level of erosion protection. Daily use of a stabilized stannous fluoride dentifrice has been shown to provide the most effective means of protecting teeth against the increasing risk of dental erosion and erosive tooth wear.

Effect of various rinsing protocols after use of amine fluoride/stannous fluoride toothpaste on the bacterial composition of dental plaque

NARCIS (Netherlands)

van Loveren, C.; Gerardu, V.A.M.; Sissons, C.H.; van Bekkum, M.; ten Cate, J.M.

2009-01-01

This clinical study evaluated the effect of different oral hygiene protocols on the bacterial composition of dental plaque. After a 2-week period of using fluoride-free toothpaste, 30 participants followed three 1-week experimental protocols, each followed by 2-week fluoride-free washout periods in

Evaluation of diode laser and stannous fluoride in the treatment of root sensitivity after access flap surgery: Randomized controlled clinical trial.

Science.gov (United States)

Raut, Chetan Purushottam; Sethi, Kunal Sunder; Kohale, Bhagyashree; Mamajiwala, Alefiya; Warang, Ayushya

2018-01-01

Postsurgical root sensitivity has always been an enigma to the periodontists. There is a plethora of evidence suggesting the presence of root sensitivity following periodontal flap surgical procedures. Thus, the aim of the present study was to compare and evaluate the effect of low-power diode lasers with and without topical application of stannous fluoride (SnF 2 ) gel in the treatment of root sensitivity and also evaluate whether laser creates any placebo effect in the control group or not. Thirty patients participated in this study and 99 teeth were included. Root sensitivity was assessed for all groups with a Verbal Rating Scale (VRS). For each patient, the teeth were randomized into three groups. In the test Group I, sensitive teeth were treated with SnF 2 and diode laser. In the test Group II, sensitive teeth were irradiated with laser only. In the control group, no treatment was performed. The mean ± standard deviation (SD) score for VRS and Visual Analog Scale at baseline was not statistically significant ( P > 0.05) between the three groups. After 15 min, statistical significant difference was seen in test Group I and test Group II, although no difference was found in the control group. At 15 th day and 30 th day, the mean ± SD scores were statistically significant ( P diode lasers alone and in combination with 0.4% SnF 2 was effective in the treatment of root sensitivity after access flap surgery.

Hexamethyldisilazane Removal with Mesoporous Materials Prepared from Calcium Fluoride Sludge.

Science.gov (United States)

Kao, Ching-Yang; Lin, Min-Fa; Nguyen, Nhat-Thien; Tsai, Hsiao-Hsin; Chang, Luh-Maan; Chen, Po-Han; Chang, Chang-Tang

2018-05-01

A large amount of calcium fluoride sludge is generated by the semiconductor industry every year. It also requires a high amount of fuel consumption using rotor concentrators and thermal oxidizers to treat VOCs. The mesoporous adsorbent prepared by calcium fluoride sludge was used for VOCs treatment. The semiconductor industry employs HMDS to promote the adhesion of photo-resistant material to oxide(s) due to the formation of silicon dioxide, which blocks porous adsorbents. The adsorption of HMDS (Hexamethyldisiloxane) was tested with mesoporous silica materials synthesized from calcium fluoride (CF-MCM). The resulting samples were characterized by XRD, XRF, FTIR, N2-adsorption-desorption techniques. The prepared samples possessed high specific surface area, large pore volume and large pore diameter. The crystal patterns of CF-MCM were similar with Mobil composite matter (MCM-41) from TEM image. The adsorption capacity of HMDS with CF-MCM was 40 and 80 mg g-1, respectively, under 100 and 500 ppm HMDS. The effects of operation parameters, such as contact time and mixture concentration, on the performance of CF-MCM were also discussed in this study.

Effect of various rinsing protocols after use of amine fluoride/stannous fluoride toothpaste on the bacterial composition of dental plaque.

Science.gov (United States)

van Loveren, C; Gerardu, V A M; Sissons, C H; van Bekkum, M; ten Cate, J M

2009-01-01

This clinical study evaluated the effect of different oral hygiene protocols on the bacterial composition of dental plaque. After a 2-week period of using fluoride-free toothpaste, 30 participants followed three 1-week experimental protocols, each followed by 2-week fluoride-free washout periods in a randomized crossover examiner-blind controlled trial. The 1-week experimental protocols comprised the use of AmF/SnF(2) toothpaste twice daily, after which participants either (1) rinsed with tap water, (2) did not rinse but only spat out the toothpaste, or (3) rinsed with an AmF/SnF(2) mouthwash. In the fluoride-free washout periods, the participants brushed their teeth with fluoride-free toothpaste without further instructions. Six hours after the last brushing (+/- rinsing) of each period, buccal plaque samples in the upper molar region were taken. The microbiota composition of the plaque samples was analyzed by checkerboard DNA:DNA hybridization. A statistically significant reduction was found in the total amount of DNA of the 39 major plaque species measured, and in the proportions of some acid-producing bacterial strains after the period having used the AmF/SnF(2) toothpaste + AmF/SnF(2) mouthrinsing. The results indicate that using the AmF/SnF(2) toothpaste and rinse combination could result in plaque of lower cariogenicity. Copyright 2009 S. Karger AG, Basel.

99mTc-stannous colloid white cell scintigraphy in childhood inflammatory bowel disease.

Science.gov (United States)

Peacock, Kenneth; Porn, Ute; Howman-Giles, Robert; O'Loughlin, Edward; Uren, Roger; Gaskin, Kevin; Dorney, Stuart; Kamath, Ramanand

2004-02-01

99mTc-Labeled white cell scintigraphy (WCS) has been used for the investigation of inflammatory bowel disease (IBD) in adults, but data on children are limited. The most common agent used is (99m) Tc-hexamethylpropyleneamine oxime (HMPAO); however, this agent has limitations. In a retrospective study, we assessed the use of (99m)Tc-stannous colloid WCS for the initial evaluation of children with suspected IBD. Diagnostic, endoscopic, and contrast radiography results were retrospectively collected from the medical records. Two experienced nuclear physicians unaware of the patient data interpreted the WCS results, with agreement reached by consensus. Statistical analysis was performed on the ability of WCS to detect active disease and localize it topographically and on a comparison of diagnostic methods, using a combination of clinical features and endoscopy as the reference standard. Between 1996 and 1999, 64 patients (35 male and 29 female; mean age, 12.5 y; age range, 2-19 y) had WCS performed, with IBD subsequently diagnosed in 34 patients. (99m)Tc-Stannous colloid WCS had an 88% sensitivity, 90% specificity, and 8.8 likelihood ratio for initial investigation of IBD. Agreement was poor for topographic localization of disease. Small-bowel series had a 75% sensitivity, 50% specificity, and 1.5 likelihood ratio for detecting endoscopic disease of the terminal ileum and proximal colon. Our results confirm that WCS is a useful imaging technique for the initial evaluation of patients with suspected IBD. (99m)Tc-Stannous colloid had results at least comparable to those of other WCS agents, and in children, (99m)Tc-stannous colloid WCS should be preferred in view of lower cost, shorter preparation time, and the smaller blood volumes required.

Clinical Effects of Stabilized Stannous Fluoride Dentifrice in Reducing Plaque Microbial Virulence I: Microbiological and Receptor Cell Findings.

Science.gov (United States)

Klukowska, Malgorzata; Haught, John Christian; Xie, Sancai; Circello, Ben; Tansky, Cheryl S; Khambe, Deepa; Huggins, Tom; White, Donald J

2017-06-01

Lipopolysaccharides (LPSs) and lipoteichoic acids (LTAs), or bacterial endotoxins, bind with Toll-like receptors (TLRs) that are expressed on host cells of the periodontium, thereby contributing to the periodontal pathogenicity of oral bacteria. Stannous fluoride (SnF2), an antibacterial fluoride that treats and controls gingivitis, has been shown to react with lipophilic domains/anionic charges in LPS and LTA. The effects of bacterial species and dental plaque on toll receptors can be studied using genetically engineered cell lines containing linked toll receptors on their surfaces. This randomized, examiner-blinded study examined the clinical effects of stabilized SnF2 dentifrice intervention on gingivitis and dental plaque virulence in populations exhibiting high and low levels of clinical gingivitis. Recruited populations were evaluated for gingival inflammation (MGI) and gingival bleeding (GBI) at baseline and assigned into two cohorts of 20 each, those with high (GBI > 20 sites) and low (GBI plaque at both healthy (no bleeding, PD = 2 mm), as well as clinically diseased sites (bleeding, PD = 3-4 mm), and then provided with an intervention hygiene product including a stabilized SnF2 dentifrice and a new soft bristle manual toothbrush. Following two and four weeks of assigned dentifrice use, participants returned for a re-evaluation of gingival inflammation and bleeding and repeat samplings of dental plaque. Plaque samples were analyzed by anaerobic culturing of gram negative anaerobes (GNA), as well as by incubation of subgingival sampled plaques with TLR4 transfected HEK293 cells, where gene expression was assessed by measurement of a SEAP alkaline phosphatase reporter as a marker of toll receptor activation. Clinical assessments showed statistically significant reductions in MGI (24-26%) and GBI (42-53%) gingivitis in both diseased and healthy cohorts following four weeks of dentifrice intervention. For all clinical examinations, MGI and bleeding sites were

Evaluation of diode laser and stannous fluoride in the treatment of root sensitivity after access flap surgery: Randomized controlled clinical trial

Directory of Open Access Journals (Sweden)

Chetan Purushottam Raut

2018-01-01

Full Text Available Background: Postsurgical root sensitivity has always been an enigma to the periodontists. There is a plethora of evidence suggesting the presence of root sensitivity following periodontal flap surgical procedures. Thus, the aim of the present study was to compare and evaluate the effect of low-power diode lasers with and without topical application of stannous fluoride (SnF2 gel in the treatment of root sensitivity and also evaluate whether laser creates any placebo effect in the control group or not. Materials and Methods: Thirty patients participated in this study and 99 teeth were included. Root sensitivity was assessed for all groups with a Verbal Rating Scale (VRS. For each patient, the teeth were randomized into three groups. In the test Group I, sensitive teeth were treated with SnF2and diode laser. In the test Group II, sensitive teeth were irradiated with laser only. In the control group, no treatment was performed. Results: The mean ± standard deviation (SD score for VRS and Visual Analog Scale at baseline was not statistically significant (P > 0.05 between the three groups. After 15 min, statistical significant difference was seen in test Group I and test Group II, although no difference was found in the control group. At 15th day and 30th day, the mean ± SD scores were statistically significant (P < 0.05. Conclusion: Within the limitations of the study, it can be concluded that diode lasers alone and in combination with 0.4% SnF2was effective in the treatment of root sensitivity after access flap surgery.

An investigation of the effect of the quantity of stannous ion on the quality of technetium-99m labelled albumin

International Nuclear Information System (INIS)

Billinghurst, M.W.; Rempel, S.; Westendorf, B.A.

1981-01-01

The importance of maintaining a low ratio of stannous ion to albumin molecules in order to obtain a high quality technetium-99m labelled albumin is demonstrated. It is further shown that the direct preparation of technetium-99m albumin by reduction of the technetium-99m pertechnetate with stannous ion inevitably leads to the contamination of the product with a certain amount of tin colloid which is also labelled with technetium-99m. It is demonstrated that this can be avoided by utilizing labelling techniques involving the initial formation of other technetium chelates which are less stable than the albumin complex under certain conditions, adding the albumin to that preparation, adjusting the conditions and thus allowing the albumin to become labelled with technetium-99m via an exchange with the original chelating agent. (author)

Fundamental evaluation of in vivo labeling of red blood cells with Tc-99m using stannous chloride

Energy Technology Data Exchange (ETDEWEB)

Hiraki, T; Katayama, M; Ando, I; Ando, A [Kanazawa Univ. (Japan). School of Paramedicine; Hisada, K

1982-04-01

Stannous chloride was evaluated as a stannous ion source for the in vivo labeling of red blood cells(RBC) with Tc-99m. In this study, the labeling of RBC with Tc-99m was performed by two successive intravenous administrations of stannous chloride and Tc-99m-pertechnetate, and the optimal dose of stannous chloride and the optimal time interval between the two injections were evaluated. The labeling efficiency for this procedure was also evaluated as a function of time after the pertechnetate injection. The results of our investigation revealed that the maximal in vivo RBC labeling (86%) can be obtained at 15 min after the pertechnetate injection with an i.v. dose of 12.7 ..mu..g/kg of stannous chloride followed 15 min later by an i.v. injection of Tc-99m-pertechnetate. In conclusion, stannous chloride was found to be an excellent stannous ion source for the in vivo labeling of RBC with Tc-99m.

Preparation and chemical crystallographic study of new hydrides and hydro-fluorides of ionic character; Preparation et etude cristallochimique de nouveaux hydrures et fluorohydrures a caractere ionique

Energy Technology Data Exchange (ETDEWEB)

Park, Hyung-Ho

1988-07-22

Within the context of a growing interest in the study of reversible hydrides with the perspective of their application in hydrogen storage, this research thesis more particularly addressed the case of ternary hydrides and fluorides, and of hydro-fluorides. The author reports the development of a method of preparation of alkaline hydrides, of alkaline earth hydrides and of europium hydride, and then the elaboration of ternary hydrides. He addresses the preparation of caesium fluorides and of calcium or nickel fluorides, of Europium fluorides, and of ternary fluorides. Then, he addresses the preparation of hydro-fluorides (caesium, calcium, europium fluorides, and caesium and nickel fluorides). The author presents the various experimental techniques: chemical analysis, radio-crystallographic analysis, volumetric mass density measurement, magnetic measurements, ionic conductivity measurements, Moessbauer spectroscopy, and nuclear magnetic resonance. He reports the crystallographic study of some ternary alkaline and alkaline-earth hydrides (KH-MgH{sub 2}, RbH-CaH{sub 2}, CsH-CaH{sub 2}, RbH-MgH{sub 2} and CsH-MgH{sub 2}) and of some hydro-fluorides (CsCaF{sub 2}H, EuF{sub 2}H, CsNiF{sub 2}H) [French] Dans une premiere partie, de nouveaux hydrures ternaires ont ete prepares et caracterises. Les systemes etudies sont AH-MH 2 (A = K, Rb, Cs et M = Mg, Ca). Dans les systemes AH-MgH 2 l'evolution structurale a ete discutee en fonction du caractere iono-covalent de la liaison magnesium-hydrogene. Dans une deuxieme partie, plusieurs nouveaux fluorohydrures ont ete mis en evidence. L'effet de la substitution de l'hydrogene au fluor dans ces phases a ete etudiee en utilisant la RMN, la spectroscopie Moessbauer, la conductivite ionique et les mesures magnetiques.

The effect of daily fluoride mouth rinsing on enamel erosive/abrasive wear in situ.

Science.gov (United States)

Stenhagen, K R; Hove, L H; Holme, B; Tveit, A B

2013-01-01

It is not known whether application of fluoride agents on enamel results in lasting resistance to erosive/abrasive wear. We investigated if one daily mouth rinse with sodium fluoride (NaF), stannous fluoride (SnF(2)) or titanium tetrafluoride (TiF(4)) solutions protected enamel against erosive/abrasive wear in situ (a paired, randomised and blind study). Sixteen molars were cut into 4 specimens, each with one amalgam filling (measurement reference surface). Two teeth (2 × 4 specimens) were mounted bilaterally (buccal aspects) on acrylic mandibular appliances and worn for 9 days by 8 volunteers. Every morning, the specimens were brushed manually with water (30 s) extra-orally. Then fluoride solutions (0.4% SnF(2) pH 2.5; 0.15% TiF(4) pH 2.1; 0.2% NaF pH 6.5, all 0.05 M F) were applied (2 min). Three of the specimens from each tooth got different treatment, and the fourth served as control. At midday, the specimens were etched for 2 min in 300 ml fresh 0.01 M hydrochloric acid and rinsed in tap water. This etch procedure was repeated in the afternoon. Topographic measurements were performed by a white-light interferometer. Mean surface loss (±SD) for 16 teeth after 9 days was: SnF(2) 1.8 ± 1.9 µm, TiF(4) 3.1 ± 4.8 µm, NaF 26.3 ± 4.7 µm, control 32.3 ± 4.4 µm. Daily rinse with SnF(2), TiF(4) and NaF resulted in 94, 90 and 18% reduction in enamel erosive/abrasive wear, respectively, compared with control (p < 0.05). The superior protective effect of daily rinse with either stannous or titanium tetrafluoride solutions on erosive/abrasive enamel wear is promising. Copyright © 2012 S. Karger AG, Basel.

On-site preparation of technetium-99m labeled human serum albumin for clinical application

International Nuclear Information System (INIS)

Wang Yuhfeng; Chuang Meihua; Cham Thauming; Chung Meiing; Chiu Jainnshiun

2007-01-01

Technetium-99m labeled human serum albumin (Tc-99m HSA) is an important radiopharmaceutical for clinical applications, such as cardiac function tests or protein-losing gastroenteropathy assessment. However, because of transfusion-induced infectious diseases, the safety of serum products is a serious concern. In this context, serum products acquired from patients themselves are the most ideal tracer. However, the development of rapid separation and easy clinical labeling methods is not yet well established. Under such situation, products from the same ethnic group or country are now recommended by the World Health Organization as an alternative preparation. This article describes the on-site preparation of Tc-99m HSA from locally supplied serum products. Different formulations were prepared and the labeling efficiency and stability were examined. Radio-labeling efficiencies were more than 90% in all preparation protocols, except for one that omitted the stannous solution. The most cost-effective protocol contained HSA 0.1 mg, treated with stannous fluoride 0.2 mg, and mixed with Tc-99m pertechnetate 30 mCi. A biodistribution study was performed in rats using a gamma camera immediately after intravenous administration of radiolabeled HSA. Tissue/organ uptake was obtained by measuring the radioactivity in organs after sacrificing the rats at timed intervals. The biologic half-life was about 32 min, determined from sequential venous blood collections. These data indicate that our preparation of Tc-99m HSA is useful and potentially applicable clinically. In addition, this on-site preparation provides the possibility of labeling a patient's own serum for subsequent clinical application. (author)

“Self-Peel-Off” Transfer Produces Ultrathin Polyvinylidene-Fluoride-Based Flexible Nanodevices

KAUST Repository

Tai, Yanlong

2017-02-23

Here, a new strategy, self-peel-off transfer, for the preparation of ultrathin flexible nanodevices made from polyvinylidene-fluoride (PVDF) is reported. In this process, a functional pattern of nanoparticles is transferred via peeling from a temporary substrate to the final PVDF film. This peeling process takes advantage of the differences in the work of adhesion between the various layers (the PVDF layer, the nanoparticle-pattern layer and the substrate layer) and of the high stresses generated by the differential thermal expansion of the layers. The work of adhesion is mainly guided by the basic physical/chemical properties of these layers and is highly sensitive to variations in temperature and moisture in the environment. The peeling technique is tested on a variety of PVDF-based functional films using gold/palladium nanoparticles, carbon nanotubes, graphene oxide, and lithium iron phosphate. Several PVDF-based flexible nanodevices are prepared, including a single-sided wireless flexible humidity sensor in which PVDF is used as the substrate and a double-sided flexible capacitor in which PVDF is used as the ferroelectric layer and the carrier layer. Results show that the nanodevices perform with high repeatability and stability. Self-peel-off transfer is a viable preparation strategy for the design and fabrication of flexible, ultrathin, and light-weight nanodevices.

Determination of stannous tin in radiopharmaceutical cold kits

International Nuclear Information System (INIS)

Farrant, A.J.

1979-01-01

Two methods for determining stannous tin in 'cold kits', used for the preparation of Tc-99m labelled radiopharmaceuticals, have been developed. Both are based on the direct titration of the Sn2 in solution. In the first method titration is with N-bromosuccinimide. Of the materials commonly used as cold kits only albumin has been found to interfere with the determination. The second method is a standard iodometric titration in which starch is used as indicator. None of the materials tested interfere with this procedure. The N-bromosuccinimide method is the method of choice as the re-agent, a solid, can be used without prior standardization. Iodine solution must be standardized daily. The paper describes in detail the methods used and gives examples of kits in which the Sn2 levels have been determined using the described procedures

An intercomparison of the thermoluminescent efficiency of various preparations of lithium fluoride

CERN Document Server

Driscoll, C M H

1977-01-01

Possible alternative sources of supply of lithium fluoride to that used at present in the NRPB automated TLD system dosemeter are being considered on the grounds of economy and quality control. Initial measurements on the thermoluminescent properties and efficiency of various preparations of lithium fluoride are described, including the Harshaw TLD-700 which is currently in use in the automated thermoluminescent dosemeter. Material obtained from British Nuclear Fuels Ltd (which may be an atypical batch) showed 75% of the sensitivity of the Harshaw material, with around 20% fading of the signal after 1 month's storage. French material, obtained from Desmarquest and Carbonisation Entreprise et Ceramique and used by the Commissariat a l'Energie Atomique, showed good fading resistance but, after standard preparational treatments, was only half as sensitive in the thermoluminescent response. Without additional treatments to improve the characteristics of these materials, they cannot be considered as being satisfac...

Preparation of Ti3C2 and Ti2C MXenes by fluoride salts etching and methane adsorptive properties

Science.gov (United States)

Liu, Fanfan; Zhou, Aiguo; Chen, Jinfeng; Jia, Jin; Zhou, Weijia; Wang, Libo; Hu, Qianku

2017-09-01

Here we reported the preparation of Ti3C2 MXene and Ti2C MXene by etching Ti3AlC2 and Ti2AlC with various fluoride salts in hydrochloric acid (HCl), including lithium fluoride (LiF), sodium fluoride (NaF), potassium fluoride (KF), and ammonium fluoride (NH4F). As-prepared Ti2C was further delaminated by urea, dimethylsulfoxide or ammonium hydroxide. Based on theoretical calculation and XPS results, the type of positive ions (Li+, Na+, K+, or NH4+) in etchant solution affect the surface structure of prepared MXene, which, in turn, affects the methane adsorption properties of MXene. The highest methane adsorption capacity is 8.5 cm3/g for Ti3C2 and 11.6 cm3/g for Ti2C. MXenes made from LiF and NH4F can absorb methane under high pressure and can keep methane under normal pressure, these MXenes may have important application on capturing methane or other hazardous gas molecules. MXenes made from NaF and KF can absorb methane under high pressure and release methane under low pressure. They can have important application in the adsorb storage of nature gas.

Abstracts of Research Project Reports by National Naval Dental Center First-, Second-, and Third-Year Residents - June 1980.

Science.gov (United States)

1980-08-30

resin ( Silar ). Extracted teeth were thermocycled at 60 and 450 C and incu- bated in a strong solution of tea. In a double-blind study, three dentists...Concise, the other with Silar . Each tooth had a control preparation and an experimental preparation. Both preparations were filled according to the...significantly I.ss than Silar . Although the initial resuits indicate that stannous fluoride applied to acid-etched enamel does not increase the

Formulation and characterization of lutetium-177-labeled stannous (tin) colloid for radiosynovectomy.

Science.gov (United States)

Arora, Geetanjali; Singh, Manoranjan; Jha, Pragati; Tripathy, Sarthak; Bal, Chandrasekhar; Mukherjee, Anirban; Shamim, Shamim A

2017-07-01

Easy large-scale production, easy availability, cost-effectiveness, long half-life, and favorable radiation characteristics have made lutetium-177 (Lu) a preferred radionuclide for use in therapy. Lutetium-177-labeled stannous (Lu-Sn) colloid particles were formulated for application in radiosynovectomy, followed by in-vitro and in-vivo characterization. Stannous chloride (SnCl2) solution and Lu were heated together, the pH was adjusted, and the particles were recovered by centrifugation. The heating time and amount of SnCl2 were varied to optimize the labeling protocol. The labeling efficiency (LE) and radiochemical purity (RCP) of the product were determined. The size and shape of the particles were determined by means of electron microscopy. In-vitro stability was tested in PBS and synovial fluid, and in-vivo stability was tested in humans. LE and RCP were greater than 95% and ∼99% (Rf=0-0.1), respectively. Aggregated colloidal particles were spherical (mean size: 241±47 nm). The product was stable in vitro for up to 7 days in PBS as well as in synovial fluid. Injection of the product into the infected knee joint of a patient resulted in its homogenous distribution in the intra-articular space, as seen on the scan. No leakage of activity was seen outside the knee joint even 7 days after injection, indicating good tracer binding and in-vivo stability. Lu-Sn colloid was successfully prepared with a high LE (>95%) and high RCP (99%) under optimized reaction conditions. Because of the numerous benefits of Lu and the ease of preparation of tin colloid particles, Lu-Sn colloid particles are significantly superior to its currently available counterparts for use in radiosynovectomy.

Effect of stannous chloride combined with caffeine on fecundity of Drosophila prosaltans

Directory of Open Access Journals (Sweden)

Mary Massumi Itoyama

2000-03-01

Full Text Available The present study analyzed the number of progeny of stannous chloride- and/or caffeine-treated Drosophila prosaltans. A significant decreasing effect was observed in every case when compared to the control, except for the smallest stannous chloride dose used. Combinations of both substances using two different stannous chloride doses did not differ significantly from each other but number of progeny decreased 15% with the higher concentration combination when compared with caffeine-treated flies. The present results and data in the literature indicate that the effects of continuous ingestion of stannous chloride should be studied.A fecundidade de Drosophila prosaltans foi analisada em indivíduos tratados com íon estanoso, cafeína ou íon estanoso, em duas concentrações, combinado com cafeína. Em todos os casos, a fecundidade foi significativamente menor quando comparada com o controle, exceto na menor concentração de íon estanoso. Nas combinações das duas substâncias, a redução não foi significativamente maior que a causada pela cafeína sozinha, podendo indicar que o efeito das duas substâncias juntas corresponde ao próprio efeito da cafeína separada. Mas a redução da fecundidade foi 15% maior no tratamento que utilizou íon estanoso em maior concentração, sugerindo que seu efeito tóxico nesse parâmetro, mesmo em combinação com a cafeína, não deve ser desconsiderado.

An In-vitro Study of the Load Deflection Characteristics of the Thermal Wires Immersed in Different Fluoride Prophylactic Agents

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Sami K. Al-Joubori

2018-04-01

Full Text Available Background: Fluoridated prophylactic agents have been reported to cause corrosion and discoloration of titanium alloys. Degradation in the mechanical properties lead to a decrease in a suitable orthodontic force, thereby causing delayed leveling of crooked teeth. This study was designed to evaluate the load deflection characteristics of thermal nickel titanium arch wires during unloading phase after ninety minutes immersion in three different fluoride agents. Material and methods: Forty specimens of thermal wires were obtained from Ortho Technology Company, which had 0.019” × 0.025” rectangular in cross section. Ten specimens from the wire size were immersed in one of the tested fluoride prophylactic agents (neutral sodium fluoride gel, stannous fluoride gel or Phos-Flur® mouth rinse or in the controlled medium of normal saline and incubated at 37°C for ninety minutes. A Wp 300 universal material testing machine was modified and used to perform a three-point bending test in a water path at 37 ± 1°C. The statistical difference between the different agents was analyzed using ANOVA and least significant difference tests. Results: The unloading forces at 0.5 mm, 1.0 mm, and 1.5 mm where significantly reduced especially in acidulated phosphate fluoride treated specimens followed by neutral fluoride treated specimens. Conclusion: Based on the results found in this study it can be preferred to use fluoride prophylactic agents with the least acidity and fluoride ions concentration.

Preparation and study of chlorine mono-fluoride and of chlorine oxi-fluorides; Preparation et etude du monofluorure et des oxyfluorures de chlore

Energy Technology Data Exchange (ETDEWEB)

Macheteau, Yves

1969-07-01

The objective of this engineering school report was to be a contribution to the study of a family of fluorine compounds: chlorine mono-fluoride (ClF), chlorine fluoride oxide (ClOF), chloryl fluoride (ClO{sub 2}F), perchloryl fluoride (ClO{sub 3}F) and perchloryl oxi-fluoride (ClO{sub 4}F). Such a study required very pure products to be obtained in order to be able to characterize them by different methods (infrared, micro-sublimation, and chromatography). The thermolysis of ClO{sub 2}F and ClO{sub 4}F has been particularly studied, and magnetic resonance has been used to establish a relationship between fluorine chemical displacement and the electro-negativity of the F-X bond where X represents the atom group to which fluorine is bonded.

Investigation of the interaction of hydroxyapatite with technetium in association with stannous pyrophosphate

International Nuclear Information System (INIS)

Billinghurst, M.W.; Jette, D.; Somers, E.

1981-01-01

The individual components of technetium-99m stannous pyrophosphate were studied with respect to their interaction with hydroxyapatite. It is demonstrated that the role of the pyrophosphate molecule is one of a solubilizing and transporting molecule to carry the technetium atom to the site of the hydroxyapatite where the chelate disassociates and both the pyrophosphate and the technetium individually bind to the hydroxyapatite. The stannous ion is shown to associate with the hydroxyapatite also and although also solubilized by the pyrophosphate appears to be less strongly associated with the pyrophosphate. (author)

Chemical resistivity of self-assembled monolayer covalently attached to silicon substrate to hydrofluoric acid and ammonium fluoride

Science.gov (United States)

Saito, N.; Youda, S.; Hayashi, K.; Sugimura, H.; Takai, O.

2003-06-01

Self-assembled monolayers (SAMs) were prepared on hydrogen-terminated silicon substrates through chemical vapor deposition using 1-hexadecene (HD) as a precursor. The HD-SAMs prepared in an atmosphere under a reduced pressure (≈50 Pa) showed better chemical resistivities to hydrofluoric acid and ammonium fluoride (NH 4F) solutions than that of an organosilane SAM formed on oxide-covered silicon substrates. The surface covered with the HD-SAM was micro-patterned by vacuum ultraviolet photolithography and consequently divided into two areas terminated with HD-SAM or silicon dioxide. This micro-patterned sample was immersed in a 40 vol.% NH 4F aqueous solution. Surface images obtained by an optical microscopy clearly show that the micro-patterns of HD-SAM/silicon dioxide were successfully transferred into the silicon substrate.

Penetration of fluoride-containing self-gelling liquids into human molar occlusal fissures in vitro.

Science.gov (United States)

Bottenberg, P; Slop, D; Coomans, D

1989-01-01

In this in vitro study the ability and speed of self-gelling liquid compositions to penetrate into fissures were evaluated. Two formulations containing either tetraethylsilicate, ammonium fluoride, and sodium lauryl sulfate or tetraethylsilicate, sodium fluoride, and cetylpyridinium chloride at different concentrations were used. It is shown that fissure penetration occurs when a certain minimum content of surface-active agent is present. Fissure penetration is achieved within 3-4 s, according to the fissure morphology.

The antimicrobial efficacy of commercial dentifrices.

Science.gov (United States)

Haraszthy, Violet I; Zambon, Joseph J; Sreenivasan, Prem K

2010-01-01

This investigation compared the effects of a fluoride dentifrice and toothpastes formulated with antimicrobial ingredients (stannous fluoride and triclosan/copolymer) on oral micro-organisms, including those found in samples taken from the human oral cavity. Microbiological techniques determined the minimum inhibitory concentrations (MICs) of each dentifrice necessary to inhibit the growth of bacterial strains from the healthy oral cavity, as well as those found in dental caries, periodontal disease, and halitosis. Ex vivo studies utilized oral rinse samples and supragingival plaque from adults to determine antimicrobial effects on the entire microbial diversity of these samples, including biofilm-derived micro-organisms. The triclosan/copolymer dentifrice demonstrated the lowest MICs and significantly inhibited Gram-positive and Gram-negative bacteria (including the periodontal pathogens Aggregatibacter actinomycetemcomitans, Eikenella corrodens, and Fusobacterium nucleatum). In the ex vivo tests, the triclosan/copolymer dentifrice demonstrated substantial inhibition in the oral rinse samples over each treatment period (p > 0.0005) as compared to either the fluoride or stannous fluoride dentifrices. Similarly, the triclosan/copolymer dentifrice demonstrated the highest inhibition of micro-organisms in the supragingival plaque biofilm (p fluoride and stannous fluoride dentifrices (p > 0.5).

Preparation and Characterization of UV Emitting Fluoride Phosphors for Phototherapy Lamps

Science.gov (United States)

Belsare, P. D.; Moharil, S. V.; Joshi, C. P.; Omanwar, S. K.

2011-10-01

The use of ultraviolet radiation for the treatment of various skin diseases is well known for long time. Phototherapy employs ultraviolet-blue radiation to cure skin diseases. The basis of phototherapy is believed to be the direct interaction of light of certain frequencies with tissue to cause a change in immune response. Currently dermatologists use UV lamps having specific emissions in UV region for treating various skin diseases. The treatment of skin diseases using artificial sources of UV radiation is now well established and more than 50 types of skin diseases are treated by phototherapy. This is an effective treatment for many skin disorders, such as psoriasis, vitiligo, ofujis disease, morphea , scleroderma, cutaneous T-cell lymphoma, lupus erythematosus, hyperbilirubinemia commonly known as infant jaundice, acne vulgaris, This paper reports photoluminescence properties of UV emitting fluoride phosphors prepared by wet chemical method. Emission characteristics of these phosphors are found similar to those of commercial UV lamp phosphors with comparable intensities. The usefulness of UV emitting fluoride phosphor is discussed in the paper.

Preparation and Characterization of Rare Earth Doped Fluoride Nanoparticles

Directory of Open Access Journals (Sweden)

Timothy A. DeVol

2010-03-01

Full Text Available This paper reviews the synthesis, structure and applications of metal fluoride nanoparticles, with particular focus on rare earth (RE doped fluoride nanoparticles obtained by our research group. Nanoparticles were produced by precipitation methods using the ligand ammonium di-n-octadecyldithiophosphate (ADDP that allows the growth of shells around a core particle while simultaneously avoiding particle aggregation. Nanoparticles were characterized on their structure, morphology, and luminescent properties. We discuss the synthesis, properties, and application of heavy metal fluorides; specifically LaF3:RE and PbF2, and group IIA fluorides. Particular attention is given to the synthesis of core/shell nanoparticles, including selectively RE-doped LaF3/LaF3, and CaF2/CaF2 core/(multi-shell nanoparticles, and the CaF2-LaF3 system.

Antiplaque and antigingivitis toothpastes.

Science.gov (United States)

Sanz, Mariano; Serrano, Jorge; Iniesta, Margarita; Santa Cruz, Isabel; Herrera, David

2013-01-01

Dentifrices are a general term used to describe preparations that are used together with a toothbrush with the purpose to clean and/or polish the teeth. Active toothpastes were first formulated in the 1950s and included ingredients such as urea, enzymes, ammonium phosphate, sodium lauryl sarcosinate and stannous fluoride. Later, therapeutic agents were included. Today's toothpastes have two objectives: to help the toothbrush in cleaning the tooth surface and to provide a therapeutic effect. The therapeutic effect may have an antiplaque or anti-inflammatory basis when the nature of the agents is antimicrobial. Plaque inhibitory and antiplaque activity of toothpastes used for chemical plaque control is evaluated in distinct consecutive stages, the last being home use randomized clinical trials of at least 6 months' duration. In this chapter, the scientific evidence supporting the use of the most common antiplaque agents, included in toothpaste formulations, is reviewed, with a special emphasis on 6-month clinical trials, and systematic reviews with meta-analyses of the mentioned studies. Among the active agents, the following have been included in toothpastes: enzymes, amine alcohols, herbal or natural products, triclosan, bisbiguanides (chlorhexidine), quaternary ammonium compounds (cetylpyridinium chloride) and different metal salts (zinc salts, stannous fluoride, stannous fluoride with amine fluoride). Dentifrices are the ideal vehicles for any active ingredient used as an oral health preventive measure since they are used in combination with toothbrushing, which is the most frequently employed oral hygiene method. The most important indications of dentifrices with active ingredients are associated with long-term use to prevent bacterial biofilm formation, mostly in gingivitis patients or in patients on supportive periodontal therapy. Copyright © 2013 S. Karger AG, Basel.

Removal of fluoride by thermally activated carbon prepared from neem (Azadirachta indica) and kikar (Acacia arabica) leaves.

Science.gov (United States)

Kumar, Sunil; Gupta, Asha; Yadav, J P

2008-03-01

The present investigation deals with fluoride removal from aqueous solution by thermally activated neem (Azadirachta indica) leaves carbon (ANC) and thermally activated kikar (Acacia arabica) leaves carbon (AKC) adsorbents. In this study neem leaves carbon and kikar leaves carbon prepared by heating the leaves at 400 degrees C in electric furnace was found to be useful for the removal of fluoride. The adsorbents of 0.3 mm and 1.0 mm sizes of neem and kikar leaves carbon was prepared by standard sieve. Batch experiments done to see the fluoride removal properties from synthetic solution of 5 ppm to study the influence of pH, adsorbent dose and contact time on adsorption efficiency The optimum pH was found to be 6 for both adsorbents. The optimum dose was found to be 0.5g/100 ml forANC (activated neem leaves carbon) and 0.7g/100 ml forAKC (activated kikar leaves carbon). The optimum time was found to be one hour for both the adsorbent. It was also found that adsorbent size of 0.3 mm was more efficient than the 1.0 mm size. The adsorption process obeyed Freundlich adsorption isotherm. The straight line of log (qe-q) vs time at ambient temperature indicated the validity of langergren equation consequently first order nature of the process involved in the present study. Results indicate that besides intraparticle diffusion there maybe other processes controlling the rate which may be operating simultaneously. All optimized conditions were applied for removal of fluoride from four natural water samples.

Fluoride loaded polymeric nanoparticles for dental delivery.

Science.gov (United States)

Nguyen, Sanko; Escudero, Carlos; Sediqi, Nadia; Smistad, Gro; Hiorth, Marianne

2017-06-15

The overall aim of the present paper was to develop fluoride loaded nanoparticles based on the biopolymers chitosan, pectin, and alginate, for use in dental delivery. First, the preparation of nanoparticles in the presence of sodium fluoride (NaF) as the active ingredient by ionic gelation was investigated followed by an evaluation of their drug entrapment and release properties. Chitosan formed stable, spherical, and monodisperse nanoparticles in the presence of NaF and tripolyphoshate as the crosslinker, whereas alginate and pectin were not able to form any definite nanostructures in similar conditions. The fluoride loading capacity was found to be 33-113ppm, and the entrapment efficiency 3.6-6.2% for chitosan nanoparticles prepared in 0.2-0.4% (w/w) NaF, respectively. A steady increase in the fluoride release was observed for chitosan nanoparticles prepared in 0.2% NaF both in pH5 and 7 until it reached a maximum at time point 4h and maintained at this level for at least 24h. Similar profiles were observed for formulations prepared in 0.4% NaF; however the fluoride was released at a higher level at pH5. The low concentration, but continuous delivery of fluoride from the chitosan nanoparticles, with possible expedited release in acidic environment, makes these formulations highly promising as dental delivery systems in the protection against caries development. Copyright © 2017 Elsevier B.V. All rights reserved.

Fluoride release, recharge and flexural properties of polymethylmethacrylate containing fluoridated glass fillers.

Science.gov (United States)

Al-Bakri, I A; Swain, M V; Naoum, S J; Al-Omari, W M; Martin, E; Ellakwa, A

2014-06-01

The purpose of this study was to investigate the effect of fluoridated glass fillers on fluoride release, recharge and the flexural properties of modified polymethylmethacrylate (PMMA). Specimens of PMMA denture base material with various loading of fluoridated glass fillers (0%, 1%, 2.5%, 5% and 10% by weight) were prepared. Flexural properties were evaluated on rectangular specimens (n = 10) aged in deionized water after 24 hours, 1 and 3 months. Disc specimens (n = 10) were aged for 43 days in deionized water and lactic acid (pH 4.0) and fluoride release was measured at numerous intervals. After ageing, specimens were recharged and fluoride re-release was recorded at 1, 3 and 7 days after recharge. Samples containing 2.5%, 5% and 10% glass fillers showed significantly (p glass fillers specimens. All experimental specimens exhibited fluoride release in both media. The flexural strength of specimens decreased in proportion to the percentage filler inclusion with the modulus of elasticity values remaining within ISO Standard 1567. The modified PMMA with fluoridated glass fillers has the ability to release and re-release fluoride ion. Flexural strength decreased as glass filler uploading increased. © 2014 Australian Dental Association.

Preparation of Bioactive Titanium Surfaces via Fluoride and Fibronectin Retention

Directory of Open Access Journals (Sweden)

Carlos Nelson Elias

2012-01-01

Full Text Available Statement of Problem. The chemical or topographic modification of the dental implant surface can affect bone healing, promote accelerated osteogenesis, and increase bone-implant contact and bonding strength. Objective. In this work, the effects of dental implant surface treatment and fibronectin adsorption on the adhesion of osteoblasts were analyzed. Materials and Methods. Two titanium dental implants (Porous-acid etching and PorousNano-acid etching followed by fluoride ion modification were characterized by high-resolution scanning electron microscopy, atomic force microscopy, and X-ray diffraction before and after the incorporation of human plasma fibronectin (FN. The objective was to investigate the biofunctionalization of these surfaces and examine their effects on the interaction with osteoblastic cells. Results. The evaluation techniques used showed that the Porous and PorousNano implants have similar microstructural characteristics. Spectrophotometry demonstrated similar levels of fibronectin adsorption on both surfaces (80%. The association indexes of osteoblastic cells in FN-treated samples were significantly higher than those in samples without FN. The radioactivity values associated with the same samples, expressed as counts per minute (cpm, suggested that FN incorporation is an important determinant of the in vitro cytocompatibility of the surfaces. Conclusion. The preparation of bioactive titanium surfaces via fluoride and FN retention proved to be a useful treatment to optimize and to accelerate the osseointegration process for dental implants.

Preparation of novel poly(vinylidene fluoride)/TiO2 photocatalysis membranes for use in direct contact membrane distillation

Science.gov (United States)

Li, Yukun; Dong, Shuying; Zhu, Liang

2018-03-01

Immobilization of TiO2 is a potential approach to obtain photocatalytic membranes that could eliminate concentration polarization in sewage disposal for direct contact membrane distillation (DCMD) process. A simple non-solvent-induced phase separation (NIPS) method was proposed to prepare poly(vinylidene fluoride) (PVDF) membrane, and the double-coating technology was further used to prepare the self-cleaning membranes with different TiO2 content. The effects of TiO2 nano-particles on membrane crystal form, morphology, porosity, pore size, pore size distribution, hydrophobicity, permeation, and photocatalytic efficiency were investigated, respectively. The flux of the prepared membranes is higher than the membrane (MS) provided by Membrane Solutions, LLC, in DCMD process. The contact angle between water and membrane could be increased 22° by introducing photocatalytic layer containing TiO2. During the photocatalytic test, 65.78-96.31% degrading rate of 15 mg/L Rhodamine B (RhB) was achieved. The relative flux of the membrane T-3 can be recovered to 0.96 in photocatalysis-membrane reactor for 8 h UV radiation. The fabricated membrane has great potential in high-salty dyeing wastewater treatment due to its high hydrophobicity and photocatalytic capability. [Figure not available: see fulltext.

Preparation of one-vial reduced anti-CEA kit

International Nuclear Information System (INIS)

Hamada, Elena Setuko; Muramoto, Emiko; Shiraishi, Emilia Mayumi; Silva, Licia Maria Britto da; Martins, Heidi Pinto; Silva, Constanca Pagano Goncalves da

1996-01-01

A rapid and reliable instant reduced anti-CEA lyophilized kit for labelling with 99m Tc was developed. Each vial contains 0.5 mg of reduced anti-CEA, 40 μg of mendronate (MDP), 2.75 μg stannous fluoride (Sn F 2 ) and 15 μ g p-aminobenzoic acid (PABA). Labeling efficiency and stability were higher than 95% and were determined by instant paper chromatography. Biodistribution studies were performed in normal isogenic BALB/c mice at 4,6 and 24 hours after intravenous administration of the radiolabelled product. The maximum amount of activity was accumulated in the liver followed by intestines and kidneys. (author)

Preparation of polycrystalline lithium-yttrium fluoride for subsequent mono crystallization

International Nuclear Information System (INIS)

Kowalczyk, E.; Radomski, J.; Diduszko, R.; Iwanejko, J.; Kowalczyk, Z.; Grasza, K.

1994-01-01

High purity lithium-yttrium (YLF) doped with rare earth elements (Nd, Pr, Ho or Tm) was obtained in a two-stage synthesis consisting of (1) reaction of ammonium fluoride with a mixture of lithium carbonate, yttrium oxide, and oxides of lanthanides, and (2) heating of the obtained reaction products at a temperature of about 700 C in an inert gas atmosphere. The phase and chemical purities of the obtained materials were characterized by X-ray diffraction and mass spectrometry techniques. Single crystal growth tests were carried out by means of the Bridgman method. The results showed that the proposed method for manufacture of polycrystalline YLF doped with rare earth elements is appropriate in principle but some parameters of the preparation process are to be more strictly defined. (author). 9 refs, 4 figs, 1 tab

Preparation of polycrystalline lithium-yttrium fluoride for subsequent mono crystallization

Energy Technology Data Exchange (ETDEWEB)

Kowalczyk, E.; Radomski, J.; Diduszko, R.; Iwanejko, J. [Institute of Vacuum Technology, Warsaw (Poland); Kowalczyk, Z. [Warsaw Univ. (Poland); Grasza, K. [Polska Akademia Nauk, Warsaw (Poland). Inst. Fizyki

1994-12-31

High purity lithium-yttrium (YLF) doped with rare earth elements (Nd, Pr, Ho or Tm) was obtained in a two-stage synthesis consisting of (1) reaction of ammonium fluoride with a mixture of lithium carbonate, yttrium oxide, and oxides of lanthanides, and (2) heating of the obtained reaction products at a temperature of about 700 C in an inert gas atmosphere. The phase and chemical purities of the obtained materials were characterized by X-ray diffraction and mass spectrometry techniques. Single crystal growth tests were carried out by means of the Bridgman method. The results showed that the proposed method for manufacture of polycrystalline YLF doped with rare earth elements is appropriate in principle but some parameters of the preparation process are to be more strictly defined. (author). 9 refs, 4 figs, 1 tab.

Preparation of plutonium fluoride to obtain metal of high purity; Preparation de fluorures de plutonium pour l'obtention de metal de haute purete

Energy Technology Data Exchange (ETDEWEB)

Faugeras, P; Brut, A; Helou, R [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1960-07-01

In the process of treating irradiated uranium, plutonium can be separated from the majority of the fission products and from the uranium by TBP extraction cycles. The high purity necessary for metallurgical and nuclear physics experiments led us to consider more elaborate purification processes, and a specially adapted method of fluoride preparation. The first part of the paper describes purification cycles of plutonium in solution on ion exchange resins, and the results are given. The second part contains the description and results of the fluoride preparation method. (author) [French] Dans le processus du traitement de l'uranium irradie, les cycles d'extraction au TBP permettent la separation du plutonium de la majorite des produits de fission et de l'uranium. La haute purete exigee pour les experiences de metallurgie et de physique nucleaire nous a conduit a envisager des purifications plus poussee et un mode de confection des fluorures specialement adapte. La premiere partie de l'expose decrit et donne les resultats de cycles de purification du plutonium en solution sur des resines echangeuses d'ions. La seconde partie decrit et donne les resultats du mode de confection des fluorures. (auteur)

Preparation of 99 sup(m)Tc labeled fibrinogen

International Nuclear Information System (INIS)

Almeida, M.A.T.M. de; Silva, C.P.G. da.

1984-01-01

A simple method for the preparation of 99 sup(m) TC labelled Fibrinogen using stannous chloride as reducing agent of 99 sup(m) TcO- 4 ion is presented. A sample of 20 mg of Fibrinogen is dissolved in 2 ml of buffer carbonate (pH=8) and 0.3 ml stannous chloride 0.2% is added. A sterile solution of sodium pertechnetate 99 sup(m) Tc eluted from a Mo-Tc generator is immediately added. The mixture rests for 30 minutes and after this period, the obtained yield is about 70%. The lyophilized kits also presented a yield of 70%, being therefore suitable for medical applications. (Author) [pt

Technetium-99m labeled radiodiagnostic agents and method of preparation

International Nuclear Information System (INIS)

Molinski, V.J.; Wilczewski, J.A.

1977-01-01

A method of preparing improved technetium-99m labeled radiodiagnostic agents by reducing technetium-99m with stannous tartrate is described. Such radiodiagnostic agents are useful in scintigraphic examinations of the bone and lung

Dental fluorosis in populations from Chiang Mai, Thailand with different fluoride exposures - paper 1: assessing fluorosis risk, predictors of fluorosis and the potential role of food preparation.

Science.gov (United States)

McGrady, Michael G; Ellwood, Roger P; Srisilapanan, Patcharawan; Korwanich, Narumanas; Worthington, Helen V; Pretty, Iain A

2012-06-21

To determine the severity of dental fluorosis in selected populations in Chiang Mai, Thailand with different exposures to fluoride and to explore possible risk indicators for dental fluorosis. Subjects were male and female lifetime residents aged 8-13 years. For each child the fluoride content of drinking and cooking water samples were assessed. Digital images were taken of the maxillary central incisors for later blind scoring for TF index (10% repeat scores). Interview data explored previous cooking and drinking water use, exposure to fluoride, infant feeding patterns and oral hygiene practices. Data from 560 subjects were available for analysis (298 M, 262 F). A weighted kappa of 0.80 was obtained for repeat photographic scores. The prevalence of fluorosis (TF 3+) for subjects consuming drinking and cooking water with a fluoride concentration of cooking water >0.9 ppm F the prevalence of fluorosis (TF 3+) rose to 37.3%. Drinking and cooking water at age 3, water used for infant formula and water used for preparing infant food all demonstrated an increase in fluorosis severity with increase in water fluoride level (p cooking water (≥1.6 ppm). The consumption of drinking water with fluoride content >0.9 ppm and use of cooking water with fluoride content >1.6 ppm were associated with an increased risk of aesthetically significant dental fluorosis. Fluoride levels in the current drinking and cooking water sources were strongly correlated with fluorosis severity. Further work is needed to explore fluorosis risk in relation to total fluoride intake from all sources including food preparation.

Fluoride levels in commercially available rice in Ethiopia | Tegegne ...

African Journals Online (AJOL)

Alkaline fusion was used for sample preparation of six varieties for both the raw rice and rice cooked with tap water and fluoridated water. Fluoride levels ranged from 0.1-5.5 mg/kg in raw rice sample. Rice which was cooked with different fluoride levels of water showed increment depending on the method of cooking.

Pore Structure and Fluoride Ion Adsorption Characteristics of Zr (IV) Surface-Immobilized Resin Prepared Using Polystyrene as a Porogen

Science.gov (United States)

Mizuki, Hidenobu; Ito, Yudai; Harada, Hisashi; Uezu, Kazuya

Zr(IV) surface-immobilized resins for removal of fluoride ion were prepared by surface template polymerization using polystyrene as a porogen. At polymerization, polystyrene was added in order to increase mesopores (2-50 nm) and macropore (>50 nm) with large macropores (around 300 nm) formed with internal aqueous phase of W⁄O emulsion. The pore structure of Zr(IV) surface-immobilized resins was evaluated by measuring specific surface area, pore volume, and pore size distribution with volumetric adsorption measurement instrument and mercury porosimeter. The adsorption isotherms were well fitted by Langmuir equation. The removal of fluoride was also carried out with column method. Zr(IV) surface-immobilized resins, using 10 g⁄L polystyrene in toluene at polymerization, possessed higher volume of not only mesopores and macropores but also large macropores. Furethermore, by adding the polystyrene with smaller molecular size, the pore volume of mesopores, macropores and large macropores was significantly increased, and the fluoride ion adsorption capacity and the column utilization also increased.

Contribution to the study of pertechnetate (sup(99m)Tc) stannous citrate - citric acid complexation

International Nuclear Information System (INIS)

Calmes, E.-P.

1978-03-01

Pertechnetate/citric acid/stannous citrate complexation carried out from a lyophilisate of stannous citrate in citric medium at pH5 leads to the formation of separable compounds. These compounds are tin-free technetium citrates. Similar results have been described in the case of complexation reactions with glycolic, thioglycolic and thiomalic acids and with other carboxylates such as dimercaptosuccinic acid. These processes include the reduction of Tcsup(VIII) by Snsup(II) in the presence of thiomalic acid under conditions similar to our own: stannous thiomalate in thiomalic medium to which is added the pertechnetate solution producing Tc-thiomalate complexes variable with the reaction pH. Also worth considering is the possible complexation between pertechnetate and the same acid in the absence of reducing ion, following a special procedure (heating). The complexes described here contain the oxotechnetium bond (terminal oxygen-technetium) and a strong probability exists in favour of dimerisation. Their stability, for a reaction in acid solution: pH 5.0/5.5, becomes satisfactory if: the solution is concentrated enough; bubbling by an inert gas is carried out; room temperature is not exceeded. The development takes place through a partial reoxidation characterised by colour change. An original interaction between reduced states of Tc and citric acid may be claimed with certainty under our experimental conditions. The difficulty then lies in the passage to the tracer stage when the isotope sup(99m)Tc is used [fr

Dental fluorosis in populations from Chiang Mai, Thailand with different fluoride exposures – Paper 1: assessing fluorosis risk, predictors of fluorosis and the potential role of food preparation

Directory of Open Access Journals (Sweden)

McGrady Michael G

2012-06-01

Full Text Available Abstract Background To determine the severity of dental fluorosis in selected populations in Chiang Mai, Thailand with different exposures to fluoride and to explore possible risk indicators for dental fluorosis. Methods Subjects were male and female lifetime residents aged 8–13 years. For each child the fluoride content of drinking and cooking water samples were assessed. Digital images were taken of the maxillary central incisors for later blind scoring for TF index (10% repeat scores. Interview data explored previous cooking and drinking water use, exposure to fluoride, infant feeding patterns and oral hygiene practices. Results Data from 560 subjects were available for analysis (298 M, 262 F. A weighted kappa of 0.80 was obtained for repeat photographic scores. The prevalence of fluorosis (TF 3+ for subjects consuming drinking and cooking water with a fluoride concentration of 0.9 ppm F the prevalence of fluorosis (TF 3+ rose to 37.3%. Drinking and cooking water at age 3, water used for infant formula and water used for preparing infant food all demonstrated an increase in fluorosis severity with increase in water fluoride level (p  Conclusions The consumption of drinking water with fluoride content >0.9 ppm and use of cooking water with fluoride content >1.6 ppm were associated with an increased risk of aesthetically significant dental fluorosis. Fluoride levels in the current drinking and cooking water sources were strongly correlated with fluorosis severity. Further work is needed to explore fluorosis risk in relation to total fluoride intake from all sources including food preparation.

Unconventional fluoride conversion coating preparation and characterization

Czech Academy of Sciences Publication Activity Database

Drábiková, J.; Fintová, Stanislava; Tkacz, J.; Doležal, P.; Wasserbauer, J.

2017-01-01

Roč. 64, č. 6 (2017), s. 613-619 ISSN 0003-5599 Institutional support: RVO:68081723 Keywords : fluoride conversion coating * magnesium * corrosion Subject RIV: JK - Corrosion ; Surface Treatment of Materials OBOR OECD: Coating and films Impact factor: 0.364, year: 2016 http://www.emeraldinsight.com/doi/abs/10.1108/ACMM-02-2017-1757

Dental fluorosis in populations from Chiang Mai, Thailand with different fluoride exposures – Paper 1: assessing fluorosis risk, predictors of fluorosis and the potential role of food preparation

Science.gov (United States)

2012-01-01

Background To determine the severity of dental fluorosis in selected populations in Chiang Mai, Thailand with different exposures to fluoride and to explore possible risk indicators for dental fluorosis. Methods Subjects were male and female lifetime residents aged 8–13 years. For each child the fluoride content of drinking and cooking water samples were assessed. Digital images were taken of the maxillary central incisors for later blind scoring for TF index (10% repeat scores). Interview data explored previous cooking and drinking water use, exposure to fluoride, infant feeding patterns and oral hygiene practices. Results Data from 560 subjects were available for analysis (298 M, 262 F). A weighted kappa of 0.80 was obtained for repeat photographic scores. The prevalence of fluorosis (TF 3+) for subjects consuming drinking and cooking water with a fluoride concentration of 0.9 ppm F the prevalence of fluorosis (TF 3+) rose to 37.3%. Drinking and cooking water at age 3, water used for infant formula and water used for preparing infant food all demonstrated an increase in fluorosis severity with increase in water fluoride level (p 0.9 ppm and use of cooking water with fluoride content >1.6 ppm were associated with an increased risk of aesthetically significant dental fluorosis. Fluoride levels in the current drinking and cooking water sources were strongly correlated with fluorosis severity. Further work is needed to explore fluorosis risk in relation to total fluoride intake from all sources including food preparation. PMID:22720834

Effect of fluoride pretreatment on the solubility of synthetic carbonated apatite.

Science.gov (United States)

Barry, A B; Zhuang, H; Baig, A A; Higuchi, W I

2003-03-01

The purpose of this research was to address the following question: How is the solubility of fluoride-pretreated carbonated apatite (CAP) in aqueous acidic media related to the equilibrium solution fluoride and/or the CAP adsorbed fluoride levels? A CAP sample prepared by a precipitation method at 70 degrees C containing approximately 6% carbonate was fluoride-treated (F adsorption from neutral aqueous solutions) to yield a approximately 1000 ppm F CAP and a approximately 3300 ppm F CAP. Metastable equilibrium solubility distributions were determined in acetate buffers at pH 5.0. Solution fluoride, calcium, phosphate, and pH were determined from the equilibrated solutions. The equilibrium solution fluoride levels were extremely low, e.g., as low as approximately 0.10 ppb to approximately 0.30 ppb at 50% dissolved for the two CAP preparations. The approximately 3300 ppm F CAP yielded a lower solubility than the approximately 1000 ppm F CAP (shift in the mean pKHAP value of 1.5-2 units). This can be attributed to the lower solution F(-) for the sample containing approximately 1000 ppm fluoride compared with the approximately 3300 ppm fluoride-containing CAP. These important findings suggest that a fluoride treatment simply may provide an adsorption fluoride depot for subsequent release, providing a solution fluoride effect upon the CAP solubility and not necessarily any intrinsic alteration of the mineral solubility.

Barium fluoride surface preparation, analysis and UV reflective coatings at Lawrence Livermore National Laboratory

International Nuclear Information System (INIS)

Wuest, C.R.

1992-01-01

Lawrence Livermore National Laboratory (LLNL) has begun a program of study on barium fluoride scintillating crystals for the Barium Fluoride Electromagnetic Calorimeter Collaboration. This program has resulted in a number of significant improvements in the mechanical processing, polishing and coating of barium fluoride crystals. Techniques have been developed using diamond-loaded pitch lapping that can produce 15 angstrom RMS surface finishes over large areas. These lapped surfaces have been shown to be crystalline using Rutherford Back-scattering (RBS). Also, special polishing fixtures have been designed based on mounting technology developed for the 1.1 m diameter optics used in LLNL's Nova Laser. These fixtures allow as many as five 25--50 cm long barium fluoride crystals to be polished and lapped at a time with the necessary tolerances for the 16,000 crystal Barium Fluoride Calorimeter. In addition, results will be presented on coating barium fluoride with UV reflective layers of magnesium fluoride and aluminum

Dimercaptosuccinic acid-Tc99m: Preparation and biodistribution in rats

International Nuclear Information System (INIS)

Smal, F.; Englebienne, P.

1976-01-01

Owing to the juxtaposition of 4 ligands (2 SH groups + 2 COOH groups), dimercaptosuccinic acid has a strong chelating capacity which suits it for technetium 99 m labelling. The study is carried out in 2 stages: preparation and stability of the dimercaptosuccinic acid - stannous chloride complex (DMSA-Sn); biodistribution of DMSA-Sn-Tc99m complex in rats as a function of the following parameters: pH, relative stannous chloride and dimercaptosuccinic acid concentrations, TcO 4 volume added, injection time after labelling. The strong activity uptake obtained in rat kidneys represents a considerable step forward in the radioisotopic kidney examination and offers the prospect of clinical use [fr

Performance of novel hydroxyapatite nanowires in treatment of fluoride contaminated water.

Science.gov (United States)

He, Junyong; Zhang, Kaisheng; Wu, Shibiao; Cai, Xingguo; Chen, Kai; Li, Yulian; Sun, Bai; Jia, Yong; Meng, Fanli; Jin, Zhen; Kong, Lingtao; Liu, Jinhuai

2016-02-13

Novel ultralong hydroxyapatite (HAP) nanowires were successfully prepared for fluoride removal for the first time. The fluoride adsorption on the HAP nanowires was studied on a batch mode. The results revealed that the adsorption data could be well described by the Freundlich model, and the adsorption kinetic followed the pseudo-second-order model. The maximum of adsorption capacity was 40.65 mg/g at pH 7.0 when the fluoride concentration is 200mg/L. The thermodynamic parameters suggested that the adsorption of fluoride was a spontaneous endothermic process. The FT-IR, XPS and Zeta potential analysis revealed that both anion exchange and electrostatic interactions were involved in the adsorption of fluoride. Furthermore, the HAP nanowires were made into HAP membrane through a simple process of suction filtration. Membrane filtration experiments revealed that the fluoride removal capabilities depended on the membrane thickness, flow rate and initial concentration of fluoride. The as-prepared membrane could remove fluoride efficiently through continues filtration. The filtered water amount could reach 350, 192, and 64 L/m(2) when the fluoride concentrations were 4, 5 and 8 ppm, respectively, using the HAP membrane with only 150 μm thickness. The as-synthesized ultralong HAP nanowires were thus demonstrated to be very effective and biocompatible adsorbents for fluoride removal from contaminated water. Copyright © 2015 Elsevier B.V. All rights reserved.

Fluoride release and surface roughness of a new glass ionomer cement: glass carbomer

Directory of Open Access Journals (Sweden)

Célia Maria Condeixa de França LOPES

2018-02-01

Full Text Available Abstract Objective This study analyzed the fluoride release/recharge and surface roughness of glass carbomer compared to other encapsulated glass ionomer cements (GICs. Material and method The GICs tested were Glass Fill® (GC-GCP Dental, Riva Self Cure® (RS-SDI, Riva Light Cure® (RL-SDI, Equia Fil® (EF-GC Europe. The composite resin Luna® (LU-SDI was used as control. Five samples of each material were prepared and kept in a humidifier for 24 hours (37 °C, 100% relative humidity. Fluoride release was measured in two times: before (T1: days 1, 2, 7, 14 and after topical application of fluoride (T2: days 15, 16, 21 and 28. The surface roughness was also measured in both times (T1: days 1 and 14; T2: days 15 and 28. All samples were submitted to a single topical application of acidulated fluoride phosphate (Fluor Care - FGM. Two-way ANOVA with repeated measures and Tukey's post-test (p <0.05 were used in the statistical analysis. Result Equia Fil presented the highest fluoride release in both evaluation periods, with a higher release in T1 (p <0.05. The other materials tested, including glass carbomer presented similar release in both periods (T1 and T2. Regarding surface roughness, no significant differences were observed in the interaction between the material × time factors (T1 and T2 (p=0.966. Conclusion The GICs tested presented fluoride release and recharge ability and showed no surface roughness increase by topical application of fluoride.

Stannous Fluoride Effects on Gene Expression of Streptococcus mutans and Actinomyces viscosus.

Science.gov (United States)

Shi, Y; Li, R; White, D J; Biesbrock, A R

2018-02-01

A genome-wide transcriptional analysis was performed to elucidate the bacterial cellular response of Streptococcus mutans and Actinomyces viscosus to NaF and SnF 2 . The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of SnF 2 were predetermined before microarray study. Gene expression profiling microarray experiments were carried out in the absence (control) and presence (experimental) of 10 ppm and 100 ppm Sn 2+ (in the form of SnF 2 ) and fluoride controls for 10-min exposures (4 biological replicates/treatment). These Sn 2+ levels and treatment time were chosen because they have been shown to slow bacterial growth of S. mutans (10 ppm) and A. viscosus (100 ppm) without affecting cell viability. All data generated by microarray experiments were analyzed with bioinformatics tools by applying the following criteria: 1) a q value should be ≤0.05, and 2) an absolute fold change in transcript level should be ≥1.5. Microarray results showed SnF 2 significantly inhibited several genes encoding enzymes of the galactose pathway upon a 10-min exposure versus a negative control: lacA and lacB (A and B subunits of the galactose-6-P isomerase), lacC (tagatose-6-P kinase), lacD (tagatose-1,6-bP adolase), galK (galactokinase), galT (galactose-1-phosphate uridylyltransferase), and galE (UDP-glucose 4-epimerase). A gene fruK encoding fructose-1-phosphate kinase in the fructose pathway was also significantly inhibited. Several genes encoding fructose/mannose-specific enzyme IIABC components in the phosphotransferase system (PTS) were also downregulated, as was ldh encoding lactate dehydrogenase, a key enzyme involved in lactic acid synthesis. SnF 2 downregulated the transcription of most key enzyme genes involved in the galactose pathway and also suppressed several key genes involved in the PTS, which transports sugars into the cell in the first step of glycolysis.

Antimicrobial efficacy of oral topical agents on microorganisms associated with radiated head and neck cancer patients: an in vitro study.

Science.gov (United States)

Bidra, Avinash S; Tarrand, Jeffery J; Roberts, Dianna B; Rolston, Kenneth V; Chambers, Mark S

2011-04-01

A variety of oral topical agents have been used for prevention and management of radiotherapy-induced adverse effects. The antimicrobial nature of some of the commonly used agents is unknown. The purpose of this study was to evaluate antimicrobial efficacies of various oral topical agents on common microorganisms associated with radiated head and neck cancer patients. Seven commonly used topical oral agents-0.12% chlorhexidine with alcohol, 0.12% chlorhexidine without alcohol, baking soda-salt rinse, 0.4% stannous fluoride gel, 0.63% stannous fluoride rinse, calcium phosphate mouthrinse, and acemannan hydrogel (aloe vera) rinse-were evaluated in vitro for their antimicrobial efficacies against four common microorganisms. A combination of baking soda-salt rinse and 0.4% stannous fluoride gel was evaluated as the eighth agent. The microorganisms used were Staphylococcus aureus, group B Streptococcus, Escherichia coli, and Candida albicans. An ELISA reader was used to measure the turbidity of microbial culture wells and optical density (OD) values for each of the 960 wells recorded. Mean OD values were rank ordered based on their turbidity. One-way ANOVA with Tukey HSD post hoc analysis was used to study differences in OD values (P baking soda- salt, calcium phosphate rinse, and the combination of baking soda-salt and stannous fluoride gel. Mean OD values classified for microorganisms from lowest to highest were Escherichia coli, Staphylococcus aureus, group B Streptococcus, and Candida albicans. A significant difference among the antimicrobial efficacies of topical agents was evident for each of four microorganisms (P < .05). There was also a significant difference among the antimicrobial efficacies of the same topical agent on the four microorganisms tested (P < .05).

FLUORIDE SORPTION USING MORRINGA INDICA-BASED ACTIVATED CARBON

Directory of Open Access Journals (Sweden)

G. Karthikeyan, S. Siva Ilango

2007-01-01

Full Text Available Batch adsorption experiments using activated carbon prepared from Morringa Indica bark were conducted to remove fluoride from aqueous solution. A minimum contact time of 25 min was required for optimum fluoride removal. The influence of adsorbent, dose, pH, co-ions (cations and anions on fluoride removal by the activated carbon has been experimentally verified. The adsorption of fluoride was studied at 30 C, 40 C and 50 C. The kinetics of adsorption and adsorption isotherms at different temperatures were studied. The fluoride adsorption obeyed both Langmuir and Freundlich isotherms and followed a pseudo first order kinetic model. The thermodynamic studies revealed that the fluoride adsorption by Morringa Indica is an endothermic process indicating an increase in sorption rate at higher temperatures. The negative values of G indicate the spontaneity of adsorption. SEM and XRD studies confirmed the surface morphological characteristics of the adsorbent and the deposition of fluoride on the surface of the material.

Highly efficient fluoride adsorption from aqueous solution by nepheline prepared from kaolinite through alkali-hydrothermal process.

Science.gov (United States)

Wang, Hao; Feng, Qiming; Liu, Kun; Li, Zishun; Tang, Xuekun; Li, Guangze

2017-07-01

A direct alkali-hydrothermal induced transformation process was adopted to prepare nepheline from raw kaolinite (shortened form RK in this paper) and NaOH solution in this paper. Structure and morphology characterizations of the synthetic product showed that the nepheline possessed high degree of crystallinity and uniform surface morphology. Specific surface area of nepheline is 18 m 2 /g, with a point of zero charge at around pH 5.0-5.5. The fluoride (F - ions) adsorption by the synthetic nepheline (shortened form SN in this paper) from aqueous solution was also investigated under different experimental conditions. The adsorption process well matched the Langmuir isotherm model with an amazing maximum adsorption capacity of 183 mg/g at 323 K. The thermodynamic parameters (ΔG 0 , ΔH 0 , and ΔS 0 ) for adsorption on SN were also determined from the temperature dependence. The adsorption capacities of fluoride on SN increased with increasing of temperature and initial concentration. Initial pH value also had influence on adsorption process. Adsorption of fluoride was rapidly increased in 5-60 min and thereafter increased slowly to reach the equilibrium in about 90-180 min under all conditions. The adsorption followed a pseudo-second order rate law. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of two antimicrobial agents on early in situ biofilm formation.

NARCIS (Netherlands)

Auschill, T.M.; Hein, N.; Hellwig, E.; Follo, M.; Sculean, A.; Arweiler, N.B.

2005-01-01

OBJECTIVES: The aim of this observer-blind, controlled, three-cell cross-over study was to evaluate the influence of an amine fluoride/stannous fluoride (Meridol, 250 ppm; ASF) and a chlorhexidine mouthrinse (CHX; Chlorhexamed forte, 0.2%) compared with water on in situ biofilm growth. MATERIAL AND

Preparation of fly ash based zeolite for removal of fluoride from drinking water

Science.gov (United States)

Panda, Laxmidhar; Kar, Biswabandita; Dash, Subhakanta

2018-05-01

Fluoride contamination of drinking water is a worldwide phenomenon and scientists are working relentlessly to find ways to remove fluoride from drinking water. Out of the different methods employed for removal fluoride from drinking water adsorption process is the most suitable because in this process the adsorbent is regenerated and the process is cost effective. In the present study fly ash is used as the raw material, which is treated with alkali (NaOH) to form NaP1 zeolite. This zeolite is then subjected to characterization by standard procedures. It is found that the synthesized zeolite has more crystalline character than the raw fly ash and has also more voids and channels on its surface. The surface of the synthesized zeolite is modified with calcium chloride and the same is employed for removal of fluoride under varying pH, contact time, initial concentration of fluoride, temperature and adsorbent dose etc so as to assess the suitably or otherwise of the synthesized product.

Stannous ion determination in99mTc - radiopharmaceutical kits

International Nuclear Information System (INIS)

Almeida, M.A.T.M. de; Silva, C.P.G. da.

1989-10-01

Two simple and selective methods for determination of stannous ion in radiopharmaceutical kits are proposed. One of this permits the estimation of stannic ion. The first method used is a potentiometric tiration of Sn +2 in HCl medium using KIO 3 solution under nitrogen gas and a redox platinum electrode. The second method consist of a compleximetric tiration of tin (Sn +2 and Sn +4 ) using EDTA standart solution at pH 5.5-5.6 without use of nitrogen gas. The employed procedures indicates that both the methods can be used for routine quantitative determination of tin in most labeled radiopharmaceuticals. (author) [pt

Approaches to the accurate characterization of high purity metal fluorides and fluoride glasses

Science.gov (United States)

Beary, E. S.; Paulsen, P. J.; Rains, T. C.; Ewing, K. J.; Jaganathan, J.; Aggarwal, I.

1990-11-01

The analytical challenges posed by the measurement of trace contaminants in high purity metal fluorides require that innovative chemical preparation procedures be used to enhance existing instrumental techniques. The instrumental techniques used to analyze these difficult matrices must be sensitive enough to detect extremely low levels of trace impurities, and the background interferences derived from the matrix (metal fluoride or glass) must be minimized. A survey of analytical techniques that have the necessary characteristics to analyze these materials will be given. In addition, means of controlling the chemical blank will be presented. Mass and atomic spectrometric techniques will be discussed, specifically graphite furnace atomic absorption spectrometry (GFAAS) and inductively coupled plasma-mass spectrometry (ICP-MS). Analytical procedures using GFAAS and ICP-MS have been developed to determine sub ppb (part per billion) levels of contaminants in high purity fluoride materials.

Fluoride absorption: independence from plasma fluoride levels

International Nuclear Information System (INIS)

Whitford, G.M.; Williams, J.L.

1986-01-01

The concept that there are physiologic mechanisms to homeostatically regulate plasma fluoride concentrations has been supported by results in the literature suggesting an inverse relationship between plasma fluoride levels and the absorption of the ion from the gastrointestinal tract of the rat. The validity of the relationship was questioned because of possible problems in the experimental design. The present work used four different methods to evaluate the effect of plasma fluoride levels on the absorption of the ion in rats: (i) the percentage of the daily fluoride intake that was excreted in the urine; (ii) the concentration of fluoride in femur epiphyses; (iii) the net areas under the time-plasma fluoride concentration curves after intragastric fluoride doses; and (iv) the residual amounts or fluoride in the gastrointestinal tracts after the intragastric fluoride doses. None of these methods indicated that plasma fluoride levels influence the rate or the degree or fluoride absorption. It was concluded that, unless extremely high plasma fluoride levels are involved (pharmacologic or toxic doses), the absorption of the ion is independent of plasma levels. The results provide further evidence that plasma fluoride concentrations are not homeostatically regulated

Preparation of TiO2 hollow fibers using poly(vinylidene fluoride) hollow fiber microfiltration membrane as a template

International Nuclear Information System (INIS)

Lu Haiqiang; Zhang Lixiong; Xing Weihong; Wang Huanting; Xu Nanping

2005-01-01

TiO 2 hollow fibers were successfully prepared by using poly(vinylidene fluoride) hollow fiber microfiltration membrane as a template. The preparation procedure includes repeated impregnation of the TiO 2 precursor in the pores of the polymeric membrane, and calcination to burn off the template, producing the TiO 2 hollow fibers. The TiO 2 hollow fibers were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). TiO 2 hollow fibers with other structures, such as honeycomb monolith and spring, were also prepared by preshaping the polymeric membranes into the honeycomb structure and spring, respectively. The phase structure of the TiO 2 hollow fibers could be readily adjusted by changing the calcination temperature

Performance of novel hydroxyapatite nanowires in treatment of fluoride contaminated water

Energy Technology Data Exchange (ETDEWEB)

He, Junyong; Zhang, Kaisheng [Nano-Materials and Environmental Detection Laboratory, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031 (China); Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026 (China); Wu, Shibiao [Nano-Materials and Environmental Detection Laboratory, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031 (China); Cai, Xingguo; Chen, Kai; Li, Yulian [Nano-Materials and Environmental Detection Laboratory, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031 (China); Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026 (China); Sun, Bai; Jia, Yong; Meng, Fanli; Jin, Zhen [Nano-Materials and Environmental Detection Laboratory, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031 (China); Kong, Lingtao, E-mail: ltkong@iim.ac.cn [Nano-Materials and Environmental Detection Laboratory, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031 (China); Liu, Jinhuai [Nano-Materials and Environmental Detection Laboratory, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031 (China)

2016-02-13

Highlights: • Novel ultralong hydroxyapatite (HAP) nanowires were developed for effective defluoridation. • High fluoride adsorption capacity, 40.65 mg/g at neutral pH. • The HAP nanowire membrane efficiently removed fluoride by dynamic adsorption. • The membrane could remove more than 98% fluoride, and filtered water amount reached 350 L/m{sup 2}. - Abstract: Novel ultralong hydroxyapatite (HAP) nanowires were successfully prepared for fluoride removal for the first time. The fluoride adsorption on the HAP nanowires was studied on a batch mode. The results revealed that the adsorption data could be well described by the Freundlich model, and the adsorption kinetic followed the pseudo-second-order model. The maximum of adsorption capacity was 40.65 mg/g at pH 7.0 when the fluoride concentration is 200 mg/L. The thermodynamic parameters suggested that the adsorption of fluoride was a spontaneous endothermic process. The FT-IR, XPS and Zeta potential analysis revealed that both anion exchange and electrostatic interactions were involved in the adsorption of fluoride. Furthermore, the HAP nanowires were made into HAP membrane through a simple process of suction filtration. Membrane filtration experiments revealed that the fluoride removal capabilities depended on the membrane thickness, flow rate and initial concentration of fluoride. The as-prepared membrane could remove fluoride efficiently through continues filtration. The filtered water amount could reach 350, 192, and 64 L/m{sup 2} when the fluoride concentrations were 4, 5 and 8 ppm, respectively, using the HAP membrane with only 150 μm thickness. The as-synthesized ultralong HAP nanowires were thus demonstrated to be very effective and biocompatible adsorbents for fluoride removal from contaminated water.

Preparation of uranium ingots from double fluorides; Elaboration de lingots d'uranium a partir de fluorures doubles

Energy Technology Data Exchange (ETDEWEB)

Le Boulbin, E [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1967-05-15

A simple method has been developed for the preparation of uranium double fluorides and has given a new impetus to the study of the reduction of these compounds with a view to obtaining very pure uranium ingots. This reduction can be carried out using calcium or magnesium as the reducing agent, this latter metal being very interesting from the practical point of view. A comparative study of the heat balances of the reduction processes for the double fluorides and for uranium tetrafluoride has shown that reduction of the double fluorides is possible. The exact experimental conditions for these reductions have been determined. Our study has shown in particular that the reduction of the double salt UF{sub 4}, CaF{sub 2} by magnesium leads to the production of small (20 to 500 g) samples of high-purity uranium with a yield of 99 per cent. (author) [French] La mise au point d'une methode simple de preparation de fluorures doubles d'uranium a remis a l'ordre du jour la reduction de ces composes en vue d'obtenir des lingots d'uranium tres pur. Cette reduction peut etre conduite en utilisant du calcium ou du magnesium comme reducteur, ce dernier metal etant tres interessant du point de vue pratique. Une etude comparative des bilans thermiques des reductions des fluorures doubles et du tetrafluorure d'uranium a montre que la reduction des fluorures doubles etait possible. Les conditions experimentales precises de ces reductions ont ete determinees. Notre etude a montre, en particulier, que la reduction du sel double UF{sub 4}, F{sub 2}Ca par le magnesium permet d'obtenir sur des petites quantites de 20 a 500 g, de l'uranium de haute purete avec un rendement de 99 pour cent. (auteur)

Microwave-assisted Polymerization of D, L-Lactide with Stannous Octanoate as Catalyst

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

Poly (lactic acid) (PLA) was synthesized by microwave-assisted ring-opening poly- merization of D, L-lactide with stannous octanoate (SnOct2) as catalyst. Its weight-average molar mass (Mw) ranged from 39000 to 67000 and the polydispersity index from 1.3 to 1.7. The polymerization rate was much faster than that of the conventional thermal polymerization. A degradation of newly formed PLA in reaction mixture by microwave irradiation was observed.

Stannous ion quantitation in sup(99m)Tc-radiopharmaceutical kits

International Nuclear Information System (INIS)

Chervu, L.R.; Vallabhajosyula, B.; Mani, J.; Chun, S.B.; Blaufox, M.D.

1982-01-01

A simple and inexpensive method for the estimation of stannous ion, Sn(II), in radiopharmaceutical kits is described. The method used is a potentiometric titration of Sn(II) in 1 N HCl medium, using potassium iodate as the oxidizing agent in an atmosphere of nitrogen. The apparatus includes a pH meter, a platinum electrode, and a simple titration cell. Several commonly used radiopharmaceutical kits were analyzed for their Sn(II) content using this method. These studies indicate that the procedure can be used, as a routine quantitative test for the Sn(II) content of various sup(99m)Tc-labeled radiopharmaceuticals. (orig.)

Solubility and fluoride release in ionomers and compomers.

Science.gov (United States)

Bertacchini, S M; Abate, P F; Blank, A; Baglieto, M F; Macchi, R L

1999-03-01

The degree of solubility and the fluoride release of glass-ionomer cements and "compomers" were determined as a function of time. Three conventional glass-ionomer cements, three hybrid ionomers, and two compomers were included in the study. Disk-shaped specimens were prepared and immersed in a lactic acid solution. Solubility was evaluated from determinations of loss of mass as a function of time. To evaluate fluoride release, similar specimens were immersed in 50 mL of deionized water to which 50 mL of buffer solution was added. A fluoride ion detector was used to read the concentration of fluoride ion in the overall solution at different times after immersion. Material and time factors had a significant influence on results. The compomers showed less corrosion and fluoride release than the ionomers. Some correlation was found between solubility and fluoride leakage values. Components of both the ionomers and compomers that were studied can dissolve in water. The materials leak fluoride ions in amounts that differ according to the characteristics of the individual products.

Fluoride varnish or fluoride mouth rinse?

DEFF Research Database (Denmark)

Keller, M K; Klausen, BJ; Twetman, S

2016-01-01

OBJECTIVE: In many Danish communities, school-based fluoride programs are offered to children with high caries risk in adjunct to tooth brushing. The purpose of this field trial was to compare the caries-preventive effectiveness of two different fluoride programs in 6-12 year olds. BASIC RESEARCH...... different schools were enrolled after informed consent and their class unit was randomly allocated to one of two fluoride programs. INTERVENTIONS: One group received a semi-annual fluoride varnish applications (FV) and the other group continued with an existing program with fluoride mouth rinses once per...... in caries development over two years among children participating in a school-based fluoride varnish or mouth rinse program....

Preparation of a porous Sn@C nanocomposite as a high-performance anode material for lithium-ion batteries

Science.gov (United States)

Zhang, Yanjun; Jiang, Li; Wang, Chunru

2015-07-01

A porous Sn@C nanocomposite was prepared via a facile hydrothermal method combined with a simple post-calcination process, using stannous octoate as the Sn source and glucose as the C source. The as-prepared Sn@C nanocomposite exhibited excellent electrochemical behavior with a high reversible capacity, long cycle life and good rate capability when used as an anode material for lithium ion batteries.A porous Sn@C nanocomposite was prepared via a facile hydrothermal method combined with a simple post-calcination process, using stannous octoate as the Sn source and glucose as the C source. The as-prepared Sn@C nanocomposite exhibited excellent electrochemical behavior with a high reversible capacity, long cycle life and good rate capability when used as an anode material for lithium ion batteries. Electronic supplementary information (ESI) available: Detailed experimental procedure and additional characterization, including a Raman spectrum, TGA curve, N2 adsorption-desorption isotherm, TEM images and SEM images. See DOI: 10.1039/c5nr03093e

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.

Technetium-99m labeled radiodiagnostic agents and method of preparation

International Nuclear Information System (INIS)

1976-01-01

A method of preparing improved technetium-99m labelled radiodiagnostic agents by reducing sup(99m)Tc-pertechnetate with stannous tartrate is given. Human serum albumine (HSA) and 1-hydroxyethylidene-1,1-disodiumphosphonate (HEDSPA), which are useful in scintigraphic examinations of the lung and bone, were labelled in this way

Spatial distribution mapping of drinking water fluoride levels in Karnataka, India: fluoride-related health effects.

Science.gov (United States)

Chowdhury, Chitta R; Shahnawaz, Khijmatgar; Kumari, Divya; Chowdhury, Avidyuti; Bedi, Raman; Lynch, Edward; Harding, Stewart; Grootveld, Martin

2016-11-01

(1) To estimate the concentrations of fluoride in drinking water throughout different zones and districts of the state of Karnataka. (2) To investigate the variation of fluoride concentration in drinking water from different sources, and its relationships to daily temperature and rainfall status in the regional districts. (3) To develop an updated fluoride concentration intensity map of the state of Karnataka, and to evaluate these data in the context of fluoride-related health effects such as fluorosis and their prevalence. Aqueous standard solutions of 10, 100 and 1,000 ppm fluoride (F - ) were prepared with analytical grade Na + /F - and a buffer; TISAB II was incorporated in both calibration standard and analysis solutions in order to remove the potentially interfering effects of trace metal ions. This analysis was performed using an ion-selective electrode (ISE), and mean determination readings for n = 5 samples collected at each Karnataka water source were recorded. The F - concentration in drinking water in Karnataka state was found to vary substantially, with the highest mean values recorded being in the north-eastern zone (1.61 ppm), and the lowest in the south-western one (only 0.41 ppm). Analysis of variance (ANOVA) demonstrated that there were very highly significant 'between-zone' and 'between-districts-within-zones' sources of variation (p water source F - levels within this state. The southern part of Karnataka has low levels of F - in its drinking water, and may require fluoridation treatment in order to mitigate for dental caries and further ailments related to fluoride deficiency. However, districts within the north-eastern region have contrastingly high levels of fluoride, an observation which has been linked to dental and skeletal fluorosis. This highlights a major requirement for interventional actions in order to ensure maintenance of the recommended range of fluoride concentrations (0.8-1.5 ppm) in Karnataka's drinking water

Fluoride reactions with dental enamel following different forms of fluoride supply

International Nuclear Information System (INIS)

Hellstroem, I.; Ericsson, Y.

1976-01-01

The reactions with dental enamel of NaF as tablets dissolved in different beverages or supplied with NaCl, simulating domestic salt fluoridation, were studied in tests with enamel surfaces and enamel powder. It was confirmed that powdered enamel can react quite differently from enamel surfaces under certain conditions. Enamel surfaces took up much more fluoride (F) from orange juice than from water or milk, and neither the low pH nor the citrate content of the juice increased the formation of unstable CaF 2 in the enamel, as judged from a KOH leaching test. The F uptake by enamel surfaces from 0.25 mM NaF in 175 mM NaCl, corresponding to a dish prepared with salt containing 500 parts/10 6 F, was about 80 percent greater than from the same NaF concentration in water. This NaCl concentration did not increase the formation of CaF 2 in the enamel, as judged from the KOH test, while 350 mM NaCl caused a moderate increase. The investigations support the administration of NaF tablets with orange juice and the plans for domestic salt fluoridation. (author)

A Novel Poly(vinylidene fluoride)-Based 4-Miktoarm Star Terpolymer: Synthesis and Self-Assembly

KAUST Repository

Patil, Yogesh Raghunath; Bilalis, Panagiotis; Polymeropoulos, George; Almahdali, Sarah; Hadjichristidis, Nikolaos; Rodionov, Valentin

2018-01-01

A well-defined amphiphilic miktoarm polymer incorporating poly(vinylidene fluoride) (PVDF), polystyrene (PS), and poly(ethylene glycol) (PEG) blocks was synthesized via a combination of atom-transfer radical polymerization (ATRP), iodine transfer radical polymerization (ITP), and copper-catalyzed azide-alkyne cycloaddition (CuAAC). Morphology and self-assembly of this star polymer were examined in organic solvents and in water. The aggregates formed in water were found to possess unusual frustrated topology due to immiscibility of PS and PVDF. The polymer was evaluated for transport of small hydrophobic molecules in water.

A Novel Poly(vinylidene fluoride)-Based 4-Miktoarm Star Terpolymer: Synthesis and Self-Assembly

KAUST Repository

Patil, Yogesh Raghunath

2018-03-15

A well-defined amphiphilic miktoarm polymer incorporating poly(vinylidene fluoride) (PVDF), polystyrene (PS), and poly(ethylene glycol) (PEG) blocks was synthesized via a combination of atom-transfer radical polymerization (ATRP), iodine transfer radical polymerization (ITP), and copper-catalyzed azide-alkyne cycloaddition (CuAAC). Morphology and self-assembly of this star polymer were examined in organic solvents and in water. The aggregates formed in water were found to possess unusual frustrated topology due to immiscibility of PS and PVDF. The polymer was evaluated for transport of small hydrophobic molecules in water.

Effects of different amine fluoride concentrations on enamel remineralization.

Science.gov (United States)

Naumova, E A; Niemann, N; Aretz, L; Arnold, W H

2012-09-01

The aim of this study was to investigate the effects of decreasing fluoride concentrations on repeated demineralizing challenges on human enamel. In 24 teeth, 3mm×3mm windows were prepared on the buccal and lingual sides and treated in a cycling demineralization-remineralization model. Remineralization was achieved with 100, 10 and 0.1 ppm fluoride from anime fluoride. Coronal sections were cut through the artificial lesions, and three sections per tooth were investigated using polarized light microscopy and scanning electron microscopy with quantitative element analysis. The morphology of the lesions was studied, and the extensions of the superficial layer and the body of the lesion were measured. Using element analysis, the Ca, P and F content were determined. The body of the lesion appeared remineralized after application of 100 ppm fluoride, while remineralization of the lesion was less successful after application of 10 and 0.1 ppm fluoride. The thickness of the superficial layer increased with decreasing fluoride concentrations, and also the extension of the body of the lesion increased. Ca and P content increased with increasing fluoride concentrations. The effectiveness of fluoride in enamel remineralization increased with increasing fluoride concentration. A consistently higher level of fluoride in saliva should be a goal in caries prevention. Copyright © 2012 Elsevier Ltd. All rights reserved.

Fluoride release from fluoride varnishes under acidic conditions.

Science.gov (United States)

Lippert, F

2014-01-01

The aim was to investigate the in vitro fluoride release from fluoride varnishes under acidic conditions. Poly(methyl methacrylate) blocks (Perspex, n=3 per group) were painted with 80 ± 5 mg fluoride varnish (n=10) and placed into artificial saliva for 30 min. Then, blocks were placed into either 1% citric acid (pH 2.27) or 0.3% citric acid (pH 3.75) solutions (n=3 per solution and varnish) for 30 min with the solutions being replaced every 5 min. Saliva and acid solutions were analyzed for fluoride content. Data were analyzed using three-way ANOVA (varnish, solution, time). The three-way interaction was significant (p>0.0001). Fluoride release and release patterns varied considerably between varnishes. Fluoride release in saliva varied by a factor of more than 10 between varnishes. Some varnishes (CavityShield, Nupro, ProFluorid, Vanish) showed higher fluoride release in saliva than during the first 5 min of acid exposure, whereas other varnishes (Acclean, Enamel-Pro, MI Varnish, Vella) showed the opposite behavior. There was little difference between acidic solutions. Fluoride release from fluoride varnishes varies considerably and also depends on the dissolution medium. Bearing in mind the limitations of laboratory research, the consumption of acidic drinks after fluoride varnish application should be avoided to optimize the benefit/risk ratio.

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.

Fluoridated Water

Science.gov (United States)

... Genetics Services Directory Cancer Prevention Overview Research Fluoridated Water On This Page What is fluoride, and where is it found? What is water fluoridation? When did water fluoridation begin in the ...

Effect of CO2 Laser and Fluoride Varnish Application on Microhardness of Enamel Surface Around Orthodontic Brackets.

Science.gov (United States)

Mahmoudzadeh, Majid; Rezaei-Soufi, Loghman; Farhadian, Nasrin; Jamalian, Seyed Farzad; Akbarzadeh, Mahdi; Momeni, Mohammadali; Basamtabar, Masome

2018-01-01

Introduction: Orthodontic treatment has many advantages such as esthetic improvement and self-esteem enhancement; yet it has some disadvantages such as increasing the risk of formation of white spot lesions, because it makes oral hygiene more difficult. It is rational to implement procedures to prevent these lesions. The present study was aimed to assess the effect of CO 2 laser and fluoride varnish on the surface of the enamel surface microhardness around the orthodontic braces. Methods: Eighty extracted premolar teeth were selected, scaled, polished with nonfluoridated pumic and metal brackets were bonded to them. Then, they were randomly allocated to 5 groups: control (neither fluoride nor laser is used on enamel surfaces), fluoride (4 minutes fluoride varnish treatment of the enamel surfaces), CO 2 laser (10.6 µm CO 2 laser irradiation of the teeth), laserfluoride (fluoride application after laser irradiation) and fluoride-laser (fluoride was applied and then teeth were irradiated with laser). After surface treatment around brackets on enamel, the samples were stored in 0.1% thymol for less than 5 days and then they were exposed to a 10-day microbiological caries model. Microhardness values of enamel were evaluated with Vickers test. One sample of each group (5 teeth from 80 samples) was prepared for SEM (scanning electron microscopy) and the data from 75 remaining teeth were analyzed with analysis of variance (ANOVA) and chi-square tests (α =0.05). Results: Microhardness mean values from high to low were as follow: fluoride-laser, laser-fluoride, laser, fluoride and control. Microhardness in fluoride-laser group was significantly higher compared with that of the control group. Distribution adhesive remnant index (ARI) scores were significantly different between groups and most of bond failures occurred at the enamel-adhesive interface in groups 2 to 5 and at the adhesive-bracket interface in the control group. Conclusion: Combination of fluoride varnish and

Method of preparation of technetium-99m labelled radio-diagnostic agents and a stable non radio-active carrier

International Nuclear Information System (INIS)

1975-01-01

A method of preparing improved technetium-99m labeled radiodiagnostic agents is described by reducing technetium-99m with stannous tartrate. Such radiodiagnostic agents are useful in scintigraphic examinations of the bone and lung

Fabrication of dense panels in lithium fluoride

International Nuclear Information System (INIS)

Farcy, P.; Roger, J.; Pointud, R.

1958-04-01

The authors report a study aimed at the fabrication of large and dense lithium fluoride panels. This sintered lithium fluoride is then supposed to be used for the construction of barriers of protection against a flow of thermal neutrons. They briefly present the raw material which is used under the form of chamotte obtained through a pre-sintering process which is also described. Grain size measurements and sample preparation are indicated. Shaping, drying, and thermal treatment are briefly described, and characteristics of the sintered product are indicated

Preparation and properties of homogeneous-reinforced polyvinylidene fluoride hollow fiber membrane

Energy Technology Data Exchange (ETDEWEB)

Zhang Xuliang [State Key Laboratory of Hollow Fiber Membrane Materials and Processes, Tianjin Polytechnic University, Tianjin 300387 (China); Xiao Changfa, E-mail: xiaotjpu@163.com [State Key Laboratory of Hollow Fiber Membrane Materials and Processes, Tianjin Polytechnic University, Tianjin 300387 (China); Hu Xiaoyu; Bai Qianqian [State Key Laboratory of Hollow Fiber Membrane Materials and Processes, Tianjin Polytechnic University, Tianjin 300387 (China)

2013-01-01

Highlights: Black-Right-Pointing-Pointer The homogeneous-reinforced method has been adopted firstly in preparing of PVDF membranes. Black-Right-Pointing-Pointer The HR membranes have a favorable interfacial bonding between the coating layer and the matrix membrane. Black-Right-Pointing-Pointer The better performance of the HR membranes in protein solution can indirectly improve the service life of membranes. - Abstract: Homogeneous-reinforced (HR) polyvinylidene fluoride (PVDF) hollow fiber membranes include PVDF polymer solutions (coating layer) and the matrix membrane prepared through the dry-wet spinning process. The performance of HR membranes varies with the polymer concentration in the polymer solutions and is characterized in terms of pure water flux, rejection of protein, porosity, infiltration property, a mechanical strength test, and morphology observations by a field emission scanning electron microscope (FESEM). The results of this study indicate that the tensile strength of the HR PVDF membranes decreases slights compared with that of the matrix membrane, but the elongation at break increases much more and the hollow fiber membranes are endowed with better flexibility performance. The HR PVDF hollow fiber membranes have a favorable interfacial bonding between the coating layer and the matrix membrane, as shown by FESEM. The infiltration property is characterized by the contact angle experiments. Pure water flux decreases while the rejection ratio with an increase in polymer concentration increasing. The protein solution flux of the HR PVDF membranes is higher than that of the matrix membrane after 100 min of infiltration.

Preparation and properties of homogeneous-reinforced polyvinylidene fluoride hollow fiber membrane

International Nuclear Information System (INIS)

Zhang Xuliang; Xiao Changfa; Hu Xiaoyu; Bai Qianqian

2013-01-01

Highlights: ► The homogeneous-reinforced method has been adopted firstly in preparing of PVDF membranes. ► The HR membranes have a favorable interfacial bonding between the coating layer and the matrix membrane. ► The better performance of the HR membranes in protein solution can indirectly improve the service life of membranes. - Abstract: Homogeneous-reinforced (HR) polyvinylidene fluoride (PVDF) hollow fiber membranes include PVDF polymer solutions (coating layer) and the matrix membrane prepared through the dry-wet spinning process. The performance of HR membranes varies with the polymer concentration in the polymer solutions and is characterized in terms of pure water flux, rejection of protein, porosity, infiltration property, a mechanical strength test, and morphology observations by a field emission scanning electron microscope (FESEM). The results of this study indicate that the tensile strength of the HR PVDF membranes decreases slights compared with that of the matrix membrane, but the elongation at break increases much more and the hollow fiber membranes are endowed with better flexibility performance. The HR PVDF hollow fiber membranes have a favorable interfacial bonding between the coating layer and the matrix membrane, as shown by FESEM. The infiltration property is characterized by the contact angle experiments. Pure water flux decreases while the rejection ratio with an increase in polymer concentration increasing. The protein solution flux of the HR PVDF membranes is higher than that of the matrix membrane after 100 min of infiltration.

γ-Aminobutyric acid ameliorates fluoride-induced hypothyroidism in male Kunming mice.

Science.gov (United States)

Yang, Haoyue; Xing, Ronge; Liu, Song; Yu, Huahua; Li, Pengcheng

2016-02-01

This study evaluated the protective effects of γ-aminobutyric acid (GABA), a non-protein amino acid and anti-oxidant, against fluoride-induced hypothyroidism in mice. Light microscope sample preparation technique and TEM sample preparation technique were used to assay thyroid microstructure and ultrastructure; enzyme immunoassay method was used to assay hormone and protein levels; immunohistochemical staining method was used to assay apoptosis of thyroid follicular epithelium cells. Subacute injection of sodium fluoride (NaF) decreased blood T4, T3 and thyroid hormone-binding globulin (TBG) levels to 33.98 μg/l, 3 2.8 ng/ml and 11.67 ng/ml, respectively. In addition, fluoride intoxication induced structural abnormalities in thyroid follicles. Our results showed that treatment of fluoride-exposed mice with GABA appreciably decreased metabolic toxicity induced by fluoride and restored the microstructural and ultrastructural organisation of the thyroid gland towards normalcy. Compared with the negative control group, GABA treatment groups showed significantly upregulated T4, T3 and TBG levels (42.34 μg/l, 6.54 ng/ml and 18.78 ng/ml, respectively; Plevel and apoptosis inhibition in thyroid follicular epithelial cells. To the best of our knowledge, this is the first study to establish the therapeutic efficacy of GABA as a natural antioxidant in inducing thyroprotection against fluoride-induced toxicity. Copyright © 2015 Elsevier Inc. All rights reserved.

A novel ultrasonication method in the preparation of zirconium impregnated cellulose for effective fluoride adsorption.

Science.gov (United States)

Barathi, M; Kumar, A Santhana Krishna; Rajesh, N

2014-05-01

In the present work, we propose for the first time a novel ultrasound assisted methodology involving the impregnation of zirconium in a cellulose matrix. Fluoride from aqueous solution interacts with the cellulose hydroxyl groups and the cationic zirconium hydroxide. Ultrasonication ensures a green and quick alternative to the conventional time intensive method of preparation. The effectiveness of this process was confirmed by comprehensive characterization of zirconium impregnated cellulose (ZrIC) adsorbent using Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray spectrometry (EDX) and X-ray diffraction (XRD) studies. The study of various adsorption isotherm models, kinetics and thermodynamics of the interaction validated the method. Copyright © 2013 Elsevier B.V. All rights reserved.

Removal of fluoride from drinking water using modified ultrafine tea powder processed using a ball-mill

Energy Technology Data Exchange (ETDEWEB)

Cai, Huimei; Xu, Lingyun; Chen, Guijie; Peng, Chuanyi [School of Tea & Food Science and Technology, Anhui Agricultural University/State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, Anhui (China); Ke, Fei [School of Tea & Food Science and Technology, Anhui Agricultural University/State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, Anhui (China); School of Science, Anhui Agricultural University, Hefei 230036 (China); Liu, Zhengquan; Li, Daxiang; Zhang, Zhengzhu [School of Tea & Food Science and Technology, Anhui Agricultural University/State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, Anhui (China); Wan, Xiaochun, E-mail: xcwan@ahau.edu.cn [School of Tea & Food Science and Technology, Anhui Agricultural University/State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, Anhui (China)

2016-07-01

Highlights: • Ultrafine tea powder (UTP) was prepared by ball-milling. • A novel and high efficient biosorbent from ultrafine tea powder (UTP) for the removal of fluoride from drinking water was prepared. • Loaded ultrafine tea powder adsorbed more fluoride adsorption than loaded tea waste. • UTP-Zr performed well over a considerably wide pH range, from 3.0 to 10.0. • UTP-Zr retains Zr metal ion during defluoridation, limiting secondary pollution. - Abstract: A low-cost and highly efficient biosorbent was prepared by loading zirconium(IV) onto ball-milled, ultrafine tea powder (UTP-Zr) for removal of fluoride from drinking water. To evaluate the fluoride adsorption capacity of UTP-Zr over a wide range of conditions, the biosorbent dosage, contact time, initial pH, initial fluoride concentration and presence of other ions were varied. UTP-Zr performed well over the considerably wide pH range of 3–10. The residual concentration of Zr in the treated water was below the limit of detection (0.01 mg/L). Fluoride adsorption by the UTP-Zr biosorbent followed the Langmuir model, with a maximum adsorption capacity of 12.43 mgF/g at room temperature. The fluoride adsorption kinetics fit the pseudo-second-order kinetic model. The synthesized biosorbent was characterized by BET, SEM, EDS, XRD and XPS to reveal how UTP-Zr interacts with fluoride. Results from this study demonstrated that UTP-based biosorbents will be useful and safe for the removal of fluoride from drinking water.

Removal of fluoride from drinking water using modified ultrafine tea powder processed using a ball-mill

International Nuclear Information System (INIS)

Cai, Huimei; Xu, Lingyun; Chen, Guijie; Peng, Chuanyi; Ke, Fei; Liu, Zhengquan; Li, Daxiang; Zhang, Zhengzhu; Wan, Xiaochun

2016-01-01

Highlights: • Ultrafine tea powder (UTP) was prepared by ball-milling. • A novel and high efficient biosorbent from ultrafine tea powder (UTP) for the removal of fluoride from drinking water was prepared. • Loaded ultrafine tea powder adsorbed more fluoride adsorption than loaded tea waste. • UTP-Zr performed well over a considerably wide pH range, from 3.0 to 10.0. • UTP-Zr retains Zr metal ion during defluoridation, limiting secondary pollution. - Abstract: A low-cost and highly efficient biosorbent was prepared by loading zirconium(IV) onto ball-milled, ultrafine tea powder (UTP-Zr) for removal of fluoride from drinking water. To evaluate the fluoride adsorption capacity of UTP-Zr over a wide range of conditions, the biosorbent dosage, contact time, initial pH, initial fluoride concentration and presence of other ions were varied. UTP-Zr performed well over the considerably wide pH range of 3–10. The residual concentration of Zr in the treated water was below the limit of detection (0.01 mg/L). Fluoride adsorption by the UTP-Zr biosorbent followed the Langmuir model, with a maximum adsorption capacity of 12.43 mgF/g at room temperature. The fluoride adsorption kinetics fit the pseudo-second-order kinetic model. The synthesized biosorbent was characterized by BET, SEM, EDS, XRD and XPS to reveal how UTP-Zr interacts with fluoride. Results from this study demonstrated that UTP-based biosorbents will be useful and safe for the removal of fluoride from drinking water.

Enriched fluoride sorption using alumina/chitosan composite

Energy Technology Data Exchange (ETDEWEB)

Viswanathan, Natrayasamy, E-mail: natrayasamy_viswanathan@rediffmail.com [Department of Chemistry, Anna University Tiruchirappalli - Dindigul Campus, Dindigul 624 622, Tamil Nadu (India); Meenakshi, S., E-mail: drs_meena@rediffmail.com [Department of Chemistry, Gandhigram Rural University, Gandhigram 624 302, Tamil Nadu (India)

2010-06-15

Alumina possesses an appreciable defluoridation capacity (DC) of 1566 mg F{sup -}/kg. In order to improve its DC, it is aimed to prepare alumina polymeric composites using the chitosan. Alumina/chitosan (AlCs) composite was prepared by incorporating alumina particles in the chitosan polymeric matrix, which can be made into any desired form viz., beads, candles and membranes. AlCs composite displayed a maximum DC of 3809 mg F{sup -}/kg than the alumina and chitosan (52 mg F{sup -}/kg). The fluoride removal studies were carried out in batch mode to optimize the equilibrium parameters viz., contact time, pH, co-anions and temperature. The equilibrium data was fitted with Freundlich and Langmuir isotherms to find the best fit for the sorption process. The calculated values of thermodynamic parameters indicate the nature of sorption. The surface characterisation of the sorbent was performed by FTIR, AFM and SEM with EDAX analysis. A possible mechanism of fluoride sorption by AlCs composite has been proposed. Suitability of AlCs composite at field conditions was tested with a field sample taken from a nearby fluoride-endemic village. This work provides a potential platform for the development of defluoridation technology.

An Investigation of Fluoride Concentration in Drinking Water of Sanganer Tehsil, Jaipur District, Rajasthan, India and Defluoridation from Plant Material

Directory of Open Access Journals (Sweden)

Mohammed Arif

2014-01-01

Full Text Available Forty water samples of 20 villages of Sanganer tehsil, Jaipur district were analyzed for determining fluoride ion concentrations. High fluoride containing regions were identified on the basis of fluoride levels of the water samples and also on the prevalence rate of dental and skeletal fluorosis of the study area. Fluoride maps, which distinguish the regions containing the water sources of different ranges of fluoride ion concentrations, were also prepared by isopleth’s technique, a statistical method. Water samples containing high fluoride levels were defluoridated with low-cost materials prepared from plant byproducts. These materials successfully decrease the fluoride ions concentration to an acceptable limit (from 0.5 to 1.5 mg/L without disturbing drinking water quality standards.

Relative uptake of technetium 99m stannous colloid by neutrophils and monocytes is altered by gram-negative infection

International Nuclear Information System (INIS)

Ramsay, Stuart C.; Maggs, Jacqueline A.; Ketheesan, Natkunam; Norton, Robert; LaBrooy, Justin

2005-01-01

Gram-negative infection alters phagocytic cell function; hence, it could affect phagocytic uptake of inorganic colloids by these cells. Neutrophil and monocyte uptake of technetium 99m stannous colloid ( 99m Tc SnC) in whole blood was measured in 10 patients with gram-negative infection (Burkholderia pseudomallei) and 7 controls. Mean uptake per individual neutrophil was reduced in infection. Uptake per monocyte was not significantly different. Blood from six normal individuals was incubated with lysed B. pseudomallei and colloid, which showed reduced neutrophil uptake, but increased monocyte uptake. These results indicate that uptake of 99m Tc SnC stannous colloid can be used to measure alteration in phagocytic cell function. They suggest that infection with B. pseudomallei is associated with reduced phagocytosis by individual neutrophils, possibly through toxic effects of bacterial products. This could have immunopathogenic consequences for this gram-negative infection and may explain why it responds to granulocyte colony-stimulating factor

Urinary fluoride excretion after application of fluoride varnish and use of fluoride toothpaste in young children

DEFF Research Database (Denmark)

Lockner, Frida; Twetman, Svante; Stecksén-Blicks, Christina

2017-01-01

BACKGROUND: The efficacy and safety of combined use of topical fluoride products are essential issues that must be monitored. AIM: To assess urinary excretion of fluoride after application of two different dental varnishes containing 2.26% fluoride in 3- to 4-year-old children and to compare...... the levels with and without parallel use of fluoride toothpaste. DESIGN: Fifteen healthy children were enrolled to a randomized crossover trial that was performed in two parts: Part I with twice-daily tooth brushing with fluoride toothpaste and Part II with twice-daily brushing with a non-fluoride toothpaste....... After a 1-week run-in period, 0.1 mL of the two fluoride varnishes (Duraphat and Profluorid Varnish) was topically applied in a randomized order. Baseline and experimental urine was collected during 6-h periods. The fluoride content was determined with an ion-sensitive electrode. RESULTS...

Quantification of trace level of fluoride content in uranium oxide produced by deconversion of HEX gas by ion chromatography

International Nuclear Information System (INIS)

Unnikrishnan, E.K.; Padmakumar, P.R.; Shanmugavelu, P.; Sudhakar, T.M.; Bhowmik, A.

2015-01-01

Fluoride content in nuclear fuel is detrimental due to its corrosion behavior with cladding material. It is essential to monitor and control the fluoride concentration in nuclear material at various processing stages. Deconversion of upgraded HEX gas is carried out to produce uranium oxide. The performance of the deconversion process of HEX gas is evaluated for which trace level of fluoride concentration accompanying uranium oxide is considered as a marker. An analytical method has been developed for testing the uranium oxide produced from deconversion process of HEX gas. The method involves sample pretreatment followed by analysis using ion chromatography. The test method was validated for its performance using in house synthetic uranyl fluoride (UO 2 F 2 ) standard solutions prepared with different level of fluoride content. The results are in agreement with the expected values with the recovery in the range of 80-95%. This method has been successfully implemented for routine analysis of samples at our lab. Since UO 2 F 2 reference material is not available to validate this method, in house UO 2 F 2 standards were prepared from U 3 O 8 prepared from nuclear grade uranyl nitrate solution. UO 2 F 2 standards were prepared by converting U 3 O 8 to UO 2 F 2 by the addition of HF followed by H 2 O 2 at 200°C on a hot plate. The entire yellow colored UO 2 F 2 was dissolved in nano pure water and recrystallised several times to ensure that all free HF is removed. The crystals dried in air oven at 120° for three hours. Samples containing 1000 mg kg -1 fluoride prepared from this UO 2 F 2 , and subsequently from this sample containing 5 mg kg -1 to 35 mg kg -1 fluoride samples were prepared and analysed against fluoride CRM and the fluoride concentration obtained was analysed

Sulfonyl fluoride-based prosthetic compounds as potential 18F labelling agents.

Science.gov (United States)

Inkster, James A H; Liu, Kate; Ait-Mohand, Samia; Schaffer, Paul; Guérin, Brigitte; Ruth, Thomas J; Storr, Tim

2012-08-27

Nucleophilic incorporation of [(18)F]F(-) under aqueous conditions holds several advantages in radiopharmaceutical development, especially with the advent of complex biological pharmacophores. Sulfonyl fluorides can be prepared in water at room temperature, yet they have not been assayed as a potential means to (18)F-labelled biomarkers for PET chemistry. We developed a general route to prepare bifunctional 4-formyl-, 3-formyl-, 4-maleimido- and 4-oxylalkynl-arylsulfonyl [(18)F]fluorides from their sulfonyl chloride analogues in 1:1 mixtures of acetonitrile, THF, or tBuOH and Cs[(18)F]F/Cs(2)CO(3(aq.)) in a reaction time of 15 min at room temperature. With the exception of 4-N-maleimide-benzenesulfonyl fluoride (3), pyridine could be used to simplify radiotracer purification by selectively degrading the precursor without significantly affecting observed yields. The addition of pyridine at the start of [(18)F]fluorination (1:1:0.8 tBuOH/Cs(2)CO(3(aq.))/pyridine) did not negatively affect yields of 3-formyl-2,4,6-trimethylbenzenesulfonyl [(18)F]fluoride (2) and dramatically improved the yields of 4-(prop-2-ynyloxy)benzenesulfonyl [(18)F]fluoride (4). The N-arylsulfonyl-4-dimethylaminopyridinium derivative of 4 (14) can be prepared and incorporates (18)F efficiently in solutions of 100 % aqueous Cs(2)CO(3) (10 mg mL(-1)). As proof-of-principle, [(18)F]2 was synthesised in a preparative fashion [88(±8) % decay corrected (n=6) from start-of-synthesis] and used to radioactively label an oxyamino-modified bombesin(6-14) analogue [35(±6) % decay corrected (n=4) from start-of-synthesis]. Total preparation time was 105-109 min from start-of-synthesis. Although the (18)F-peptide exhibited evidence of proteolytic defluorination and modification, our study is the first step in developing an aqueous, room temperature (18)F labelling strategy. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preventing Tooth Decay: A Guide for Implementing Self-Applied Fluoride in Schools.

Science.gov (United States)

National Inst. of Dental Research (NIH), Bethesda, MD.

This guidebook was developed to assist citizens in initiating programs to prevent tooth decay in young children through the use of fluoridation. It contains outlines for determining the needs of the school and community for fluoride in drinking water, and presents the various steps and activities that are necessary for developing and implementing…

Synthesis and characterization of ruthenium fluorides and oxide fluorides with high oxidation states

International Nuclear Information System (INIS)

Meublat, L.

1989-10-01

The synthesis of ruthenium fluorides and oxide fluorides with high oxidation states was attempted from dioxide RuO 2 and tetroxide RuO 4 . Three fluorinating agents were used: fluorine, chlorine trifluoride and krypton difluoride. The reactions were achieved in anhydrous hydrogen fluoride at room temperature. Thus, the reaction of RuO 4 with CIF 3 enabled us to prepare chloryl hexafluororuthenate (V), CIO 2 + RuF 6 - , a new compound well identified by vibrational spectroscopy (infra-red and Raman), the structure of which was determined. The reaction of KrF 2 with RuO 4 gave the oxide tetrafluoride RuOF 4 , the previously published syntheses and properties of which were not in agreement with each other. This compound was definitely characterized here by chemical analysis, infra-red spectroscopy and X-ray powder diffraction. The product of thermal decomposition (70 0 C) of RuOF 4 is presumably RuF 4 since only oxygen is liberated during this decomposition. At last, the reaction of KrF 2 with RuO 2 probably leads to the formation of the new oxide fluoride RuO 2 F 4 . Indeed, no oxygen is given off during this reaction, the chemical analysis of the red-orange coloured solid residue is almost in agreement with the one proposed and its infra-red absorption spectrum indicates the presence of ruthenium-oxygen and ruthenium-terminal and bridging fluorine bonds [fr

Synthesis and characterization of ruthenium fluorides and oxide fluorides with high oxidation states

International Nuclear Information System (INIS)

Meublat, L.

1989-01-01

The synthesis of ruthenium fluorides and oxide fluorides with high oxidation states was attempted from dioxide RuO 2 and tetroxide RuO 4 . Three fluorinating agents were used: fluorine, chlorine trifluoride and krypton difluoride. The reactions were achieved in anhydrous hydrogen fluoride at room temperature. Thus, the reaction of RuO 4 with CIF 3 enabled us to prepare chloryl hexafluororuthenate (V), ClO 2 + RuF 6 - , a new compound well idendified by vibrational spectroscopy (infra-red and Raman), the structure of which was determined. The reaction of KrF 2 with RuO 4 gave the oxide tetrafluoride RuOF 4 , the previously published syntheses and properties of which were not in agreement with each other. This compound was definitely characterized here by chemical analysis, infra-red spectroscopy and X-ray powder diffraction. The product of thermal decomposition (70 0 C) of RuOF 4 is presumably RuF 4 since only oxygen is liberated during this decomposition. At last, the reaction of KrF 2 with RuO 2 probably leads to the formation of the new oxide fluoride RuO 2 F 4 . Indeed, no oxygen is given off during this reaction, the chemical analysis of the red-orange coloured solid residue is almost in agreement with the one proposed and its infra-red absorption spectrum indicates the presence of ruthenium-oxygen and ruthenium-terminal and bridging fluorine bonds [fr

Studies on the preparation of radioactive labelled compounds

International Nuclear Information System (INIS)

Kim, Jae-Rok; Park, Kyung-Bae; Awh, Ok-Doo

1985-04-01

To deveolp 99 mTc instant labelling kits of dimercaptosuccinic acid (DMSA), glucoheptonic acid (GH), and tin colloid, molar ratios of the host compound to the stannous chloride, amount of the stannous chloride and pH were, respectively, controlled. The labelling yields and radiochemical purities were checked by means of a paper chromatography. Animal studies and clinical applications were also carried out. The results indicated that DMSA/SnCl 2 2H 2 O 3/1(mole/mole), SnCl 2 2H 2 O 410ug/ml/vial, pH 2.5, Ca GH/SnCl 2 2H 2 O 53/1(mole/mole), SnCl 2 2H 2 O 350 ug/ml/vial, pH 6.5, NaF 100ug/vial, SnCl 2 2H 2 O 150 ug/ml/vial, pH. 5.6 etc, were optimal conditions for the preparation of DMSA-, GH-, and tin colloid-kits, respectively. (Author)

Preparation of sodium fluoride agglomerates for selective adsorption of uranium hexafluoride (U F6)

International Nuclear Information System (INIS)

Castro, A.R.; Maximiano, C.; Shimba, R.; Silva, E.R.F.

1995-01-01

Uranium hexafluoride (U F 6 ) and Sodium Fluoride (NaF) reacts reversibly to form a solid complex. Such reversibility accounts for the great interest in using Sodium Fluoride (NaF) to separate Uranium Hexafluoride (U F 6 ) from other gases. Therefore a chemical trap offers an alternative to the cryogenic trapping device. (author). 3 refs, 1 fig, 4 tabs

Removal of Fluoride from Drinking Water Using Modified Immobilized Activated Alumina

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Aneeza Rafique

2013-01-01

Full Text Available The study describes the removal of fluoride from drinking water using modified immobilized activated alumina (MIAA prepared by sol-gel method. The modification was done by adding a specific amount of alum during the sol formation step. The fluoride removal efficiency of MIAA was 1.35 times higher as compared to normal immobilized activated alumina. A batch adsorption study was performed as a function of adsorbent dose, contact time, stirring rate, and initial fluoride concentration. More than 90% removal of fluoride was achieved within 60 minutes of contact time. The adsorption potential of MIAA was compared with activated charcoal which showed that the removal efficiency was about 10% more than the activated charcoal. Both the Langmuir and Freundlich adsorption isotherms fitted well for the fluoride adsorption on MIAA with the regression coefficient R2 of 0.99 and 0.98, respectively. MIAA can both be regenerated thermally and chemically. Adsorption experiments using MIAA were employed on real drinking water samples from a fluoride affected area. The study showed that modified immobilized activated alumina is an effective adsorbent for fluoride removal.

(99m)Tc-aprotinin - optimisation and validation of radiolabelling kits for routine preparation for diagnostic imaging of amyloidosis

DEFF Research Database (Denmark)

Denholt, Charlotte; Gillings, Nic

2016-01-01

Technetium-99m aprotinin was prepared from an optimised radiolabelling kit formulation containing aprotinin, alkaline buffer and stannous chloride (reducing agent) and radiolabelled using (99m) Tc-pertechnetate. The labelling was achieved within 25 min, with radiochemical purities of >98%....

Highly selective and efficient removal of fluoride from ground water by layered Al-Zr-La Tri-metal hydroxide

Science.gov (United States)

Zhou, Jian; Zhu, Wenkun; Yu, Jie; Zhang, Hongping; Zhang, Yongde; Lin, Xiaoyan; Luo, Xuegang

2018-03-01

A novel layered Zr-Al-La tri-metal composite (AZL) was fabricated via co-precipitation method for fluoride removal. The as-prepared adsorbent was characterized by various technologies, and its adsorption behaviors to fluoride were thoroughly carried out to investigate the fluoride removal performance. The results showed that the layered structure existed and the AZL exhibited the maximum adsorption capacity of 90.48 mg g-1 at 308 K and pH 3.0 from the Langmuir isotherm model. The adsorption kinetics was well fitted by the pseudo-second-order equation, and the adsorption isotherms were well described by the Langmuir equation. Adsorption thermodynamics result was indicative of endothermic reaction in the process of adsorption of AZL to fluoride. The as-prepared AZL composite has excellent fluoride removal performance for the practical ground water and satisfies the permissible limit of fluoride in drinking water recommended by Chinese Standard. In addition, based on the characterization, the adsorption mechanism of fluoride on AZL was proposed, including electrostatic interaction between the protonated surface of AZL and fluoride, as well as ion-exchange by hydroxyl group and fluoride.

Teachers' Self-Assessed Level of Preparation

Science.gov (United States)

White, Susan

2013-01-01

We asked high school physics teachers to assess their level of preparation across a number of domains. Almost all (98%) reported feeling adequately or well prepared in terms of their basic physics knowledge. The chart presents teachers' responses to their self-assessed level of preparation in six different areas. Almost all feel at least…

Histopathological changes of renal tissue following sodium fluoride administration in two consecutive generations of mice. Correlation with the urinary elimination of fluoride.

Science.gov (United States)

Dimcevici Poesina, Nicoleta; Bălălău, Cristian; Nimigean, Vanda Roxana; Nimigean, Victor; Ion, Ion; Baconi, Daniela; Bârcă, Maria; Băran Poesina, Violeta

2014-01-01

The present study was designed to investigate the toxic effects (evaluated as histopathological changes) of sodium fluoride on the kidney in two consecutive generations of NMRI mice. An attempt to correlate the toxicity with the urinary elimination of fluoride has been made, as urinary fluoride excretion has been widely used as an indicator of fluoride intake and exposure. Six mixed (males and females) animal groups have been constituted by dividing the populations of mice derived from pregnant females (named "mothers" 0.5 mg sodium fluoride) treated with 0.5 mg sodium fluoride by daily gavage and pregnant females (named "mothers" 0.25 mg sodium fluoride) treated with 0.25 mg sodium fluoride by daily gavage; three types of sodium fluoride treatments were administrated: homeopathic, allopathic-homeopathic and allopathic. When the animals reached the adulthood, by randomization, they were selected in pairs for giving birth to the second generation of mice. No treatments were administrated to the second generation of mice; thus, the urinary elimination of fluoride in the second generation is attributed to exposure at sodium fluoride before birth. The administration of sodium fluoride to the first generation (F1) is realized until the mice reached the adulthood. For the first generation, the urine was collected at three times, every three weeks: at the age of four weeks, seven weeks and 11 weeks; single sampling urine, at the age of four weeks, has been conducted for the second generation. The urine samples have been analyzed using the ion selective electrode method for fluoride. For the histopathological examination, the animals were killed by cervical dislocation; the kidneys were collected in a 10% formalin solution. The preparation of samples for optical microscopy was realized with Hematoxylin-Eosin staining. The results indicate that the elimination of fluoride was similar (at the second evaluation, at 7-week-old of the first generation) for the both generations

Preparation of polyurethane microcapsule using 1,3 propanediol as the polyol component

International Nuclear Information System (INIS)

Ahmad Randy; Dewi Sondari; Evi Triwulandari; Murni Handayani

2010-01-01

Self-healing property is the ability of a material to heal damages automatically and autonomously. Its application would be ranged from paint coating, anti corrosion coating, space shuttle material, construction (concrete) and automotive. Extrinsic self healing requires self healing agent pre embedded or incorporated into polymer matrix that would be released and close the damage in the polymer system, where the polymer itself is not healable. Healing agents are encapsulated or embedded into the material prior application. Example of monomer encapsulated to give self healing property is isophorone diisocyanate (IPDI) encapsulated in polyurethane shell. In this study, we studied the possibility of 1,3 propanediol, that can be derived from palm oil as polyol monomer for polyurethane microcapsule shell containing IPDI or stannous octoate as a self healing agent. Microcapsule in this study was prepared by interfacial polymerization technique to form IPDI monomer in polyurethane shell. FT-IR analysis show that polyurethane prepolymer produced still have unreacted isocyanate group necessary for interfacial polymerization of polyurethane. Morphological analyses of the microcapsule products show that the products have spherical shapes with smooth surface and some with wrinkled surface. The particle sizes were ranged from 40.29 to 526.80 μm. (author)

Preparation of pyrolytic carbon coating on graphite for inhibiting liquid fluoride salt and Xe135 penetration for molten salt breeder reactor

International Nuclear Information System (INIS)

Song, Jinliang; Zhao, Yanling; He, Xiujie; Zhang, Baoliang; Xu, Li; He, Zhoutong; Zhang, DongSheng; Gao, Lina; Xia, Huihao; Zhou, Xingtai; Huai, Ping; Bai, Shuo

2015-01-01

Highlights: • Rough laminar pyrolytic carbon coating (RLPyC) is prepared by a fixed-bed method. • The salt-infiltration into IG-110 is 13.5%, less than 0.01% of RLPyC under 1.5 atm. • The helium diffusion coefficient of RLPyC coated graphite is 2.16 × 10 −8 cm 2 /s. • The coated graphite can inhibit the liquid fluoride salt and Xe 135 penetration. - Abstract: A fixed-bed deposition method was used to prepare rough laminar pyrolytic carbon coating (RLPyC) on graphite for inhibiting liquid fluoride salt and Xe 135 penetration during use in molten salt breeder reactor. The RLPyC coating possessed a graphitization degree of 44% and had good contact with graphite substrate. A high-pressure reactor was constructed to evaluate the molten salt infiltration in the isostatic graphite (IG-110, TOYO TANSO CO., LTD.) and RLPyC coated graphite under 1.01, 1.52, 3.04, 5.07 and 10.13 × 10 5 Pa for 12 h. Mercury injection and molten-salt infiltration experiments indicated the porosity and the salt-infiltration amount of 18.4% and 13.5 wt% under 1.52 × 10 5 Pa of IG-110, which was much less than 1.2% and 0.06 wt% under 10.13 × 10 5 Pa of the RLPyC, respectively. A vacuum device was constructed to evaluate the Xe 135 penetration in the graphite. The helium diffusion coefficient of RLPyC coated graphite was 2.16 × 10 −12 m 2 /s, much less than 1.21 × 10 −6 m 2 /s of the graphite. Thermal cycle experiment indicated the coatings possessed excellent thermal stability. The coated graphite could effectively inhibit the liquid fluoride salt and Xe 135 penetration

Comparative evaluation of fluoride release and recharge of pre-reacted glass ionomer composite and nano-ionomeric glass ionomer with daily fluoride exposure: An in vitro study

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Jayanthi Mungara

2013-01-01

Full Text Available Aim: This in vitro study was designed to investigate the effects of daily fluoride exposures on fluoride release and recharge by prereacted glass ionomer (PRG composite and nano-ionomeric glass ionomer. Materials and Methods: Seventy-two specimens (36 of each material were prepared and by placing the restorative materials into Teflon mold. Each specimen was subjected to one of three daily treatments (n = 12: (1 No fluoride treatment (control; (2 application of a fluoride dentifrice (1,000 ppm once daily; and (3 the same regimen as (2, plus immersion in a 0.05% sodium fluoride (NaF mouth rinse (225 ppm immediately following the dentifrice application. Specimens were suspended in a storage vial containing 10 ml demineralizing solution for 6 h and transferred to a new test tube containing 10 ml remineralizing solution for 18 h. Fluoride treatments of the specimens were completed every day prior to their immersion in the demineralizing solution. Media solutions were buffered with equal volumes of total ionic strength adjustment buffer (TISAB II; fluoride levels were measured using a digital ion analyzer and fluoride electrode throughout the 21 day duration of the experiment. Results: Nano-ionomeric glass ionomer showed a better amount of fluoride release than PRG composite irrespective of the fluoride treatment supplementation (P < 0.01. Additional fluoride supplementation improved fluoride release and recharge ability for both the materials when compared to their respective control groups. The fluoride recharge for both materials did not show any sustained pattern of release. Conclusion: Nano-ionomeric glass ionomer demonstrated a greater ability to release and recharge compared with that of PRG composite.

Preparation of potassium tantalum fluoride from tantalum hydroxide

International Nuclear Information System (INIS)

Silva, F.T. da; Espinola, A.; Dutra, A.J.B.

1987-01-01

Potassium tantalum fluoride (K 2 TaF 7 ) is an intermediary product in the processing of tantaliferous materials; it is the basic raw material for both reduction processes in use presently: reduction by metallic sodium and electrolysis in molten halides. It is normally obtained from a fluorotantalic acid solution to which potassium ions are added the precipitation of white acicular crystals of K 2 TaF 7 . The conditions for precipitation and recrystallization were studied, and crystal characterization were done by scanning electron microscopy, X-ray diffraction and thermogravimetric and thermodifferential analyses. (Author) [pt

Effect of fluoridated casein phospopeptide-amorphous-calcium phosphate complex, chlorhexidine fluoride mouthwash on shear bond strength of orthodontic brackets: A comparative in vitro study

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C A Abdul Shahariyar

2016-01-01

Full Text Available Objective: The aim of the current study was to determine the effects of casein phosphopeptide amorphous calcium-phosphate (CPP-ACP complex, chlorhexidine fluoride mouthwash on shear bond strengths (SBSs of orthodontic brackets. Materials and Methods: About sixty extracted healthy human premolar teeth with intact buccal enamel were divided into two equal groups to which brackets were bonded using self-etching primers (SEPs and conventional means respectively. These were further equally divided into three subgroups - (1 control (2 CPP-ACP (3 chlorhexidine fluoride mouthwash. The SBSs were then measured using a universal testing machine. Results: SBS of the conventional group was significantly higher than the self-etching group. The intragroup differences were statistically insignificant. Conclusion: CPP-ACP, chlorhexidine fluoride mouthwash did not adversely affect SBS of orthodontic brackets irrespective of the method of conditioning. Brackets bonded with conventional technique showed greater bond strengths as compared to those bonded with SEP.

Fluoride levels in tef [Eragrostis tef (Zucc.) Trotter] and enjera and its ...

African Journals Online (AJOL)

The main objective of this study was to estimate the fluoride levels in tef grain and in enjera, its fermentation product in different regions of Ethiopia, especially in the regions where tef is dominantly cultivated. The effect of water used to bake the enjera was assessed by preparing fluoride-containing water in the laboratory.

Barium fluoride crystals and self-quenching streamer chambers as a position sensitive gamma-ray detector

International Nuclear Information System (INIS)

Salomon, M.; DeMooy, S.; Ruggier, L.

1985-01-01

We have studied the possibility of using selfquenching streamer chambers to detect photoelectrons produced by a photoconverter in conjunction with Barium Fluoride scintillators. With the purpose to obtain a high efficiency detector, we attempted to combine a BaF 2 scintillator with a gas chamber operating at large electric fields and a high fraction of quenching gas like self-quenching streamer (SQS) chamber, as the electric fields at the cathode could be made larger than in the proportional mode. Furthermore, previous results indicated that in this mode, part of the large amplification was obtained through strong absorption of uv photons near the anode

Probing ge distribution in zeolite frameworks by post-synthesis introduction of fluoride in as-made materials

KAUST Repository

Liu, Xiaolong

2012-08-14

A new method has been developed to introduce fluoride in the structure of as-made germanium-containing zeolites prepared under pure alkaline media. Incorporation of fluoride species occurs without modification of the framework composition (Si/Ge ratio) and of the crystallinity, as evidenced by X-ray diffraction and electron microscopy. After incorporation, 19F solid-state NMR has been used to probe the location and distribution of Ge atoms in the framework. In the case of ITQ-13 and ITQ-17, which can be prepared from both hydroxide and fluoride routes, incorporated F anions are located in the same structural units as those occupied when zeolites are prepared in the presence of fluoride. In the case of ITQ-22 and ITQ-24, fluoride goes mainly in D4R units, which appear to be in the most energetically favorable positions for these zeolites. All experiments clearly show that zeolites prepared in the absence of fluoride in the synthesis medium are enriched in germanium, compared to the same materials obtained from F-containing gels. Moreover, Ge plays a strong structure-directing role by replacing Si atoms preferentially in D4R, leading to zeolites with mainly [4Si, 4Ge] units in the framework. In the particular case of ITQ-22, a new line observed around -2 ppm in 19F NMR spectra has been tentatively assigned to [3Si, 5Ge] D4R units, which corroborates the structural data obtained via X-ray diffraction. © 2012 American Chemical Society.

Effect of Preparation Methods on Crystallization Behavior and Tensile Strength of Poly(vinylidene fluoride) Membranes.

Science.gov (United States)

Liu, Jie; Lu, Xiaolong; Wu, Chunrui

2013-11-21

Poly(vinylidene fluoride) (PVDF) membranes were prepared by non solvent induced phase separation (NIPS), melt spinning and the solution-cast method. The effect of preparation methods with different membrane formation mechanisms on crystallization behavior and tensile strength of PVDF membranes was investigated. Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) and X-ray diffraction (XRD) were employed to examine the crystal form of the surface layers and the overall membranes, respectively. Spherulite morphologies and thermal behavior of the membranes were studied by polarized light optical microscopy (PLO) and differential scanning calorimetry (DSC) separately. It was found that the crystallization behavior of PVDF membranes was closely related to the preparation methods. For membranes prepared by the NIPS method, the skin layers had a mixture of α and β phases, the overall membranes were predominantly α phase, and the total crystallinity was 60.0% with no spherulite. For melt spinning membranes, the surface layers also showed a mixture of α and β phases, the overall membranes were predominantly α phase. The total crystallinity was 48.7% with perfect spherulites. Whereas the crystallization behavior of solution-cast membranes was related to the evaporation temperature and the additive, when the evaporation temperature was 140 °C with a soluble additive in the dope solution, obvious spherulites appeared. The crystalline morphology of PVDF exerted a great influence on the tensile strength of the membranes, which was much higher with perfect spherulites.

Purification of Drinking Water from Fluorides by Reverse Osmosis

Directory of Open Access Journals (Sweden)

Aleksander A.

2018-03-01

Full Text Available Introduction: An important task in the sphere of sanitary and epidemiological welfare of the population of the Russian Federation is provision of drinking water. Tap water must not contain pathogenic bacteria and dangerous chemicals. Purification systems regulate the concentration of fluoride ions in drinking water. The aim of this paper is to study the possibility of purifying tap water from fluoride ions by reverse osmosis. Materials and Methods: We used the Alfa Laval PilotUnit 2.5 "RO/NF with a set of spiral-type membrane elements RO99-2517/48 to remove fluoride ions. We measured the concentration of fluoride ions by the potentiometric method using the Hanna HI 2211 (pH/mV/T. Fluoride-selective electrode ELIS 131 F was used as an indicator electrode and the standard chloride-silver electrode EVL-1M3 was used as a reference electrode. Both the calibration and buffer solutions were prepared from chemically pure reagents and A. R. purity for analysis reagents according to GOST 4386-89. Results: A single passage of water through the reverse osmosis membrane reduced the concentration of fluoride ions from 2.29 ± 0.02 to 0.240 ± 0.015 mg/l. Double passage of water reduced the concentration by a factor of two. As the concentration of fluoride ions increased in the retentate, the concentration in the filtrate slightly increased too. Purification of water reduced the concentration of fluoride ions from 20 mg/l, to 0.5 mg/l. Discussion and Conclusions: Thus, using the Alfa Laval PilotUnit 2.5" RO/NF with a set of spiral-type membrane elements RO99-2517/48 filters tap water of ions of fluoride to the maximum allowable concentration. This study opens the perspective of using reverse osmosis to purify tap water with high concentration of fluoride ions.

INTERACTION OF FLUORIDE COMPLEXES DERIVED FROM GLASS-IONOMER CEMENTS WITH HYDROXYAPATITE

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Lewis S. M.

2013-09-01

Full Text Available A study has been undertaken of the interaction of complexed fluoride extracted from glass-ionomer dental cements with synthetic hydroxyapatite powder. Extracts were prepared from two commercial glass-ionomers (Fuji IX and ChemFlex under both neutral and acidic conditions. They were analysed by ICP-OES and by fluoride-ion selective electrode with and without added TISAB to decomplex the fluoride. The pH of the acid extracts was 4, conditions under which fluoride complexes with protons as HF or HF2-, it also complexes with aluminium, which was found to be present in higher amounts in the acid extracts. Fluoride was found to be almost completely complexed in acid extracts, but not in neutral extracts, which contained free fluoride ions. Exposure of these extracts to synthetic hydroxyapatite powder showed that fluoride was taken up rapidly (within 5 minutes, whether or not it was complexed. SEM (EDAX study of recovered hydroxyapatite showed only minute traces of aluminium taken up under all conditions. This showed that aluminium interacts hardly at all with hydroxyapatite, and hence is probably not involved in the remineralisation process.

Monitoring of fluoride in water samples using a smartphone

International Nuclear Information System (INIS)

Levin, Saurabh; Krishnan, Sunderrajan; Rajkumar, Samuel; Halery, Nischal; Balkunde, Pradeep

2016-01-01

In several parts of India, groundwater is the only reliable, year round source for drinking water. Prevention of fluorosis, a chronic disease resulting from excess intake of fluoride, requires the screening of all groundwater sources for fluoride in endemic areas. In this paper, the authors present a field deployable colorimetric analyzer based on an inexpensive smartphone embedded with digital camera for taking photograph of the colored solution as well as an easy-fit, and compact sample chamber (Akvo Caddisfly). Phones marketed by different smartphone makers were used. Commercially available zirconium xylenol orange reagent was used for determining fluoride concentration. A software program was developed to use with the phone for recording and analyzing the RGB color of the picture. Linear range for fluoride estimation was 0–2 mg l"−"1. Around 200 samples, which consisted of laboratory prepared as well as field samples collected from different locations in Karnataka, India, were tested with Akvo Caddisfly. The results showed a significant positive correlation between Ion Selective Electrode (ISE) method and Akvo Caddisfly (Phones A, B and C), with correlation coefficient ranging between 0.9952 and 1.000. In addition, there was no significant difference in the mean fluoride content values between ISE and Phone B and C except for Phone A. Thus the smartphone method is economical and suited for groundwater fluoride analysis in the field. - Highlights: • Fluoride is an inorganic pollutant in ground water, affecting human health. • A colorimetric method for measurement of fluoride in drinking water with smartphone • Measurement is by mixing water with zirconyl xylenol orange complex reagent. • Results are comparable with laboratory-based ion selective fluoride electrode method.

Monitoring of fluoride in water samples using a smartphone

Energy Technology Data Exchange (ETDEWEB)

Levin, Saurabh [Akvo Foundation (Netherlands); Krishnan, Sunderrajan [INREM Foundation (India); Rajkumar, Samuel; Halery, Nischal; Balkunde, Pradeep [Akvo Foundation (Netherlands)

2016-05-01

In several parts of India, groundwater is the only reliable, year round source for drinking water. Prevention of fluorosis, a chronic disease resulting from excess intake of fluoride, requires the screening of all groundwater sources for fluoride in endemic areas. In this paper, the authors present a field deployable colorimetric analyzer based on an inexpensive smartphone embedded with digital camera for taking photograph of the colored solution as well as an easy-fit, and compact sample chamber (Akvo Caddisfly). Phones marketed by different smartphone makers were used. Commercially available zirconium xylenol orange reagent was used for determining fluoride concentration. A software program was developed to use with the phone for recording and analyzing the RGB color of the picture. Linear range for fluoride estimation was 0–2 mg l{sup −1}. Around 200 samples, which consisted of laboratory prepared as well as field samples collected from different locations in Karnataka, India, were tested with Akvo Caddisfly. The results showed a significant positive correlation between Ion Selective Electrode (ISE) method and Akvo Caddisfly (Phones A, B and C), with correlation coefficient ranging between 0.9952 and 1.000. In addition, there was no significant difference in the mean fluoride content values between ISE and Phone B and C except for Phone A. Thus the smartphone method is economical and suited for groundwater fluoride analysis in the field. - Highlights: • Fluoride is an inorganic pollutant in ground water, affecting human health. • A colorimetric method for measurement of fluoride in drinking water with smartphone • Measurement is by mixing water with zirconyl xylenol orange complex reagent. • Results are comparable with laboratory-based ion selective fluoride electrode method.

Probing ge distribution in zeolite frameworks by post-synthesis introduction of fluoride in as-made materials

KAUST Repository

Liu, Xiaolong; Ravon, Ugo; Bosselet, Franç oise; Bergeret, Gé rard; Tuel, Alain

2012-01-01

A new method has been developed to introduce fluoride in the structure of as-made germanium-containing zeolites prepared under pure alkaline media. Incorporation of fluoride species occurs without modification of the framework composition (Si

The fluoride content of an anion exchange resin in the fluoride form

International Nuclear Information System (INIS)

Kleijn, J.P. de; Zanten, B. van

1977-01-01

The fluoride content of an anion exchange resin in the F - -form depends on the material of the equipment used for the preparation. If a glass equipment is used too much fluorine is introduced. The experimental results are explained by taking into account a competition of F - and SiF 6 2- for the hydroxyl positions of the resin (OH - ). Because SiF 6 2- is bivalent and has a lower hydration energy than F - , the resin has a much larger affinity for this species than for F - . If a higher concentration of SiF 6 2- is generated by an intensive contact of the HF solution with glass, two OH-groups may be replaced by one SiF 6 2- . This results in a resin with 3 times as much fluorine as calculated from the chloride capacity. If the formation of SiF 6 2- is impossible as for example in teflon equipment, the same capacity is obtained for chloride and fluoride. (T.G.)

Fluoride Removal From Drinking Water by Electrocoagulation Using Iron and Aluminum Electrodes

Directory of Open Access Journals (Sweden)

Takdastan

2014-07-01

Full Text Available Background Existence of fluoride in drinking water above the permissible level causes human skeletal fluorosis. Objectives Electrocoagulation by iron and aluminum electrodes was proposed for removing fluoride from drinking water. Materials and Methods Effects of different operating conditions such as treatment time, initial pH, applied voltage, type and number of electrodes, the spaces between aluminum and iron electrodes, and energy consumption during electrocoagulation were investigated in the batch reactor. Variable concentrations of fluoride solution were prepared by mixing proper amounts of sodium fluoride with deionized water. Results Experimental results showed that aluminum electrode is more effective in fluoride removal than iron, as in 40 minutes and initial pH of 7.5 at 20 V, the fluoride removal process reached to 97.86%. The final recommendable limit of fluoride (1.5 mg/L was obtained in 10 minutes at 20 V with the aluminum electrode. Conclusions In electrocoagulation with iron and aluminum electrodes, increase of voltage, number of electrodes and reaction time as well as decrease of the spaces between electrodes, enhanced the fluoride removal efficiency from drinking water. In addition the effect of pH and initial concentration of fluoride varied with types of electrodes.

Caregivers who refuse preventive care for their children: the relationship between immunization and topical fluoride refusal.

Science.gov (United States)

Chi, Donald L

2014-07-01

The aim of this study was to examine caregivers' refusal of preventive medical and dental care for children. Prevalence rates of topical fluoride refusal based on dental records and caregiver self-reports were estimated for children treated in 3 dental clinics in Washington State. A 60-item survey was administered to 1024 caregivers to evaluate the association between immunization and topical fluoride refusal. Modified Poisson regression models were used to estimate prevalence rate ratios (PRRs). The prevalence of topical fluoride refusal was 4.9% according to dental records and 12.7% according to caregiver self-reports. The rate of immunization refusal was 27.4%. In the regression models, immunization refusal was significantly associated with topical fluoride refusal (dental record PRR = 1.61; 95% confidence interval [CI] = 1.32, 1.96; P refuse both immunizations and topical fluoride (P refusal of immunizations is associated with topical fluoride refusal. Future research should identify the behavioral and social factors related to caregiver refusal of preventive care with the goal of developing multidisciplinary strategies to help caregivers make optimal preventive care decisions for children.

Development of chitosan supported zirconium(IV) tungstophosphate composite for fluoride removal

Energy Technology Data Exchange (ETDEWEB)

Viswanathan, Natrayasamy, E-mail: natrayasamy_viswanathan@rediffmail.com [Department of Chemistry, Anna University Tiruchirappalli - Dindigul Campus, Dindigul 624622, Tamil Nadu (India); Meenakshi, S., E-mail: drs_meena@rediffmail.com [Department of Chemistry, Gandhigram Rural University, Gandhigram 624302, Tamil Nadu (India)

2010-04-15

A new biocomposite was prepared by incorporating inorganic ion exchanger namely zirconium(IV) tungstophosphate (ZrWP) into the chitosan biopolymeric matrix. The sorption behaviour of fluoride from aqueous solutions by this ZrWP/chitosan (ZrWPCs) composite has been investigated by batch technique. The fluoride sorption was studied as a function of contact time, pH, initial fluoride concentration, competing co-ions and temperature. The defluoridation capacity (DC) of the adsorbent was found to be 2025 mgF{sup -} kg{sup -1}. The composite was characterized using FTIR and SEM with EDAX analysis. The equilibrium sorption data were fitted to Freundlich and Langmuir isotherms. The kinetics of sorption was found to follow pseudo-second-order and intraparticle diffusion models. The values of thermodynamic parameters indicate the nature of sorption is spontaneous and endothermic. The biocomposite was successfully used for the removal of fluoride from the field water taken in a nearby fluoride endemic village.

Preparation of pyrolytic carbon coating on graphite for inhibiting liquid fluoride salt and Xe{sup 135} penetration for molten salt breeder reactor

Energy Technology Data Exchange (ETDEWEB)

Song, Jinliang [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Zhao, Yanling, E-mail: jlsong1982@yeah.net [School of Materials Science and Engineering, University of Jinan, Jinan 250022 (China); He, Xiujie; Zhang, Baoliang [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Xu, Li [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); He, Zhoutong; Zhang, DongSheng; Gao, Lina; Xia, Huihao; Zhou, Xingtai; Huai, Ping [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Bai, Shuo [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

2015-01-15

Highlights: • Rough laminar pyrolytic carbon coating (RLPyC) is prepared by a fixed-bed method. • The salt-infiltration into IG-110 is 13.5%, less than 0.01% of RLPyC under 1.5 atm. • The helium diffusion coefficient of RLPyC coated graphite is 2.16 × 10{sup −8} cm{sup 2}/s. • The coated graphite can inhibit the liquid fluoride salt and Xe{sup 135} penetration. - Abstract: A fixed-bed deposition method was used to prepare rough laminar pyrolytic carbon coating (RLPyC) on graphite for inhibiting liquid fluoride salt and Xe{sup 135} penetration during use in molten salt breeder reactor. The RLPyC coating possessed a graphitization degree of 44% and had good contact with graphite substrate. A high-pressure reactor was constructed to evaluate the molten salt infiltration in the isostatic graphite (IG-110, TOYO TANSO CO., LTD.) and RLPyC coated graphite under 1.01, 1.52, 3.04, 5.07 and 10.13 × 10{sup 5} Pa for 12 h. Mercury injection and molten-salt infiltration experiments indicated the porosity and the salt-infiltration amount of 18.4% and 13.5 wt% under 1.52 × 10{sup 5} Pa of IG-110, which was much less than 1.2% and 0.06 wt% under 10.13 × 10{sup 5} Pa of the RLPyC, respectively. A vacuum device was constructed to evaluate the Xe{sup 135} penetration in the graphite. The helium diffusion coefficient of RLPyC coated graphite was 2.16 × 10{sup −12} m{sup 2}/s, much less than 1.21 × 10{sup −6} m{sup 2}/s of the graphite. Thermal cycle experiment indicated the coatings possessed excellent thermal stability. The coated graphite could effectively inhibit the liquid fluoride salt and Xe{sup 135} penetration.

Fluoride

Science.gov (United States)

Opalescence® ... Fluoride is used to prevent tooth decay. It is taken up by teeth and helps to strengthen ... and block the cavity-forming action of bacteria. Fluoride usually is prescribed for children and adults whose ...

Preparation and Preliminary Dialysis Performance Research of Polyvinylidene Fluoride Hollow Fiber Membranes

Science.gov (United States)

Zhang, Qinglei; Lu, Xiaolong; Liu, Juanjuan; Zhao, Lihua

2015-01-01

In this study, the separation properties of Polyvinylidene fluoride (PVDF) hollow fiber hemodialysis membranes were improved by optimizing membrane morphology and structure. The results showed that the PVDF membrane had better mechanical and separation properties than Fresenius Polysulfone High-Flux (F60S) membrane. The PVDF membrane tensile stress at break, tensile elongation and bursting pressure were 11.3 MPa, 395% and 0.625 MPa, respectively. Ultrafiltration (UF) flux of pure water reached 108.2 L∙h−1∙m−2 and rejection of Albumin from bovine serum was 82.3%. The PVDF dialyzers were prepared by centrifugal casting. The influences of membrane area and simulate fluid flow rate on dialysis performance were investigated. The results showed that the clearance rate of urea and Lysozyme (LZM) were improved with increasing membrane area and fluid flow rate while the rejection of albumin from bovine serum (BSA) had little influence. The high-flux PVDF dialyzer UF coefficient reached 62.6 mL/h/mmHg. The PVDF dialyzer with membrane area 0.69 m2 has the highest clearance rate to LZM and urea. The clearance rate of LZM was 66.8% and urea was 87.7%. PMID:25807890

Other Fluoride Products

Science.gov (United States)

... Private Wells Infant Formula Fluorosis Public Health Service Recommendation Water Operators & Engineers Water Fluoridation Additives Shortages of Fluoridation Additives Drinking Water Pipe Systems CDC-Sponsored Water Fluoridation Training Links to Other ...

Thermodynamic data for uranium fluorides

International Nuclear Information System (INIS)

Leitnaker, J.M.

1983-03-01

Self-consistent thermodynamic data have been tabulated for uranium fluorides between UF 4 and UF 6 , including UF 4 (solid and gas), U 4 F 17 (solid), U 2 F 9 (solid), UF 5 (solid and gas), U 2 F 10 (gas), and UF 6 (solid, liquid, and gas). Included are thermal function - the heat capacity, enthalpy, and free energy function, heats of formation, and vaporization behavior

Industrial fluoride pollution: chronic fluoride poisoning in Cornwall Island cattle

Energy Technology Data Exchange (ETDEWEB)

Krook, L.; Maylin, G.A.

1979-04-01

An aluminum plant on the south bank of the St. Lawrence River, southwest of Cornwall Island, Ontario, Canada, has emitted 0.816 metric tons of fluoride daily since 1973. Considerably higher amounts were emitted from 1959 to 1973. The plant was designated as the major source of fluoride emissions impacting on Cornwall Island. Cattle located on this island showed signs of chronic fluoride poisoning. This poisoning was manifested clinically by stunted growth and dental fluorosis to a degree of severe interference with drinking and mastication. This Cornwall Island herds study indicates that the established tolerance level of fluoride for performance of dairy and beef cattle is not valid since the tolerance level was set based on experiments with healthy calves which were exposed to dietary fluoride from 3 to 4 months of age and not on cattle which were chronically exposed to fluoride from conception to death. 56 references.

The Impact of Selected Fluoridated Toothpastes on Dental Erosion in Profilometric Measurement.

Science.gov (United States)

Fita, Katarzyna; Kaczmarek, Urszula

2016-01-01

Some fluoridated toothpastes, available commercially, are described to have a protective effect against dental erosion. To evaluate the influence of the selected marketed toothpastes on the human enamel exposed to acid beverages. Enamel specimens from extracted human teeth were prepared (n = 40). Specimens were randomly divided into 10 experimental groups, 4 specimens each, which were subjected to acid challenge for 10 min using orange juice (pH 3.79) or Pepsi Cola (pH 2.58) and then immersed for 2 min into a slurry of five marketed toothpastes with distilled water (1 : 3 w/w). The tested toothpastes contained 1450 or 5000 ppm fluoride, CPP-ACP with 900 ppm fluoride, 1450 ppm fluoride with potassium nitrate 5%, all of them as sodium fluoride, and 700 ppm fluoride as amine and sodium fluoride with 3500 ppm SnCl2. Enamel roughness (Ra parameter) by contact profilometer at baseline and after exposure onto soft drinks and slurry was measured. Exposure to both beverages caused a similar increase of enamel surface roughness. After the specimens immersion into slurries of toothpastes with 1450 or 5000 ppm fluoride, 1450 ppm fluoride with potassium nitrate 5% and CPP-ACP with 900 ppm fluoride the significant decrease of Ra values were found, reaching the baseline values. However, toothpaste with 700 ppm fluoride and 3500 ppm SnCl2 did not cause any fall in Ra value, probably due to other mechanism of action. Within the limitation of the study we can conclude that the sodium fluoride toothpastes are able to restore the surface profile of enamel exposed shortly to acidic soft drinks.

Urinary fluoride excretion in preschool children after intake of fluoridated milk and use of fluoride-containing toothpaste

DEFF Research Database (Denmark)

Norman, M; Twetman, S; Hultgren Talvilahti, A

2017-01-01

Objective: To assess the urinary fluoride excretion in preschool children after drinking fluoridated milk with 0.185 mg F and 0.375 mg F and to study the impact of use of fluoride toothpaste. Basic research design: Double-blind cross-over study. Participants: Nine healthy children, 2.5-4.5 years...

The precipitation of double fluoride salts of uranium

Energy Technology Data Exchange (ETDEWEB)

Muir, C. W.A.

1963-02-15

Bench-scale kinetic tests were conducted to study the reduction and precipitation reactions involved in the preparation of ammonium uranous fluoride from high-purity uranyl nitrate solutions. Sulphur dioxide and formic acid were used to form the active reducing agent, nascent hyposulphite ion. The reduction was affected in the presence of ammonium fluoride, resulting in the precipitation of the highly insoluble double salt. It was found that uranium was precipituted at a constant rate throughout the progress of the reaction. It is postulated that the reducing agent was continuously regenerated, and that this reaction was rate controlling. As a result of this study, a reaction mechanism is proposed. (auth)

Oral fluoride retention after professional topical application in children with caries activity: comparison between 1.23% fluoride foam and fluoride gel

Directory of Open Access Journals (Sweden)

Cecília Claudia Costa Ribeiro

2008-01-01

Full Text Available Objective: This study evaluated fluoride retention in the saliva of children with caries activity after topical fluoride application in the form of gel and foam. Methods: A cross-sectional, blind and randomized study, conducted with ten caries-active children aged between 8 and 10 years, in two stage, with a washout interval of two weeks between them. The treatments consisted of: a application of 2mL acidulated phosphate fluoride of the gel type in a mold and b application of 2mL acidulated phosphate fluoride of the foam type in a mold. After the washout, the treatments were inverted. Non-stimulated saliva was collected from the children at the times of 5, 15, 30 and 60 minutes after topical fluoride application. For statistical analysis the Student’s-t test was used, with a level of significance of 5%. Results: Saliva analysis was performed using a fluoride-specific electrode (ISE25F/ Radiometer, Copenhagen, Denmark at the Aquatic Science Center of the Federal University of Marana, which revealed differences after 5 minutes (p=0.0055 and 15 minutes (p=0.0208. The topical application of fluoride in the gel form revealed a higher concentration of fluoride in the saliva. Conclusion: There were differences in the retention of fluoride in the saliva of children with caries activity after the topical application of fluoride gel and the topical application of fluoride foam after 5 and 15 minutes of their application. The topical application of fluoride foam is recommended, on the basis of the lower probability of toxicity during its use.

Artificial caries formation around fluoride-releasing restorations in roots.

Science.gov (United States)

Dionysopoulos, P; Kotsanos, N; Papadogiannis, Y; Konstantinidis, A

1998-11-01

Secondary caries is one of the most important factors leading to replacement of dental restorations. This investigation assessed the capacity of fluoride-releasing restorative materials to resist caries in vitro when used in roots. Class 5 cavities were prepared in the buccal and lingual surfaces of 30 extracted premolars. The six materials used were: glass-ionomer cement (Fuji), glass-ionomer cement with silver particles added (Ketac-silver), fluoride-containing composite resin (Tetric), composite resin (Silux plus), fluoride-containing amalgam (Fluor-Alloy) and high-copper amalgam (Dispersalloy). After 5 weeks in an acid gel for caries-like lesion formation, the teeth were sectioned longitudinally and examined with polarized light. The results showed that repair with glass-ionomer materials of a carious lesion may be of great importance in the prevention of secondary caries around the restorations in roots.

Eukaryotic resistance to fluoride toxicity mediated by a widespread family of fluoride export proteins.

Science.gov (United States)

Li, Sanshu; Smith, Kathryn D; Davis, Jared H; Gordon, Patricia B; Breaker, Ronald R; Strobel, Scott A

2013-11-19

Fluorine is an abundant element and is toxic to organisms from bacteria to humans, but the mechanisms by which eukaryotes resist fluoride toxicity are unknown. The Escherichia coli gene crcB was recently shown to be regulated by a fluoride-responsive riboswitch, implicating it in fluoride response. There are >8,000 crcB homologs across all domains of life, indicating that it has an important role in biology. Here we demonstrate that eukaryotic homologs [renamed FEX (fluoride exporter)] function in fluoride export. FEX KOs in three eukaryotic model organisms, Neurospora crassa, Saccharomyces cerevisiae, and Candida albicans, are highly sensitized to fluoride (>200-fold) but not to other halides. Some of these KO strains are unable to grow in fluoride concentrations found in tap water. Using the radioactive isotope of fluoride, (18)F, we developed an assay to measure the intracellular fluoride concentration and show that the FEX deletion strains accumulate fluoride in excess of the external concentration, providing direct evidence of FEX function in fluoride efflux. In addition, they are more sensitive to lower pH in the presence of fluoride. These results demonstrate that eukaryotic FEX genes encode a previously unrecognized class of fluoride exporter necessary for survival in standard environmental conditions.

Fast and Easy Drying Method for the Preparation of Activated [{sup 18}F]Fluoride Using Polymer Cartridge

Energy Technology Data Exchange (ETDEWEB)

Seo, Jai Woong [Inha University, Inchon (Korea, Republic of); Lee, Byoung Se; Chi, Dae Yoon [FutureChem Co., Ltd., Seoul (Korea, Republic of); Lee, Sang Ju [Sogang University, Seoul (Korea, Republic of); Oh, Seung Jun [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

2011-01-15

An efficient nucleophilic [{sup 18}F]fluorination has been studied to reduce byproducts and preparation time. Instead of conventional aqueous solution of K{sub 2}CO{sub 3}-K{sub 222}, several organic solution containing inert organic salts were used to release [{sup 18}F]fluoride ion and anion bases captured in the polymer cartridge, concluding that methanol solution is the best choice. Comparing to azeotropic drying process, one min was sufficient to remove methanol completely, resulting in about 10% radioactivity saving by reducing drying time. The polymer cartridge, Chromafix (PS-HCO{sub 3}) was pretreated with several anion bases to displace pre-loaded bicarbonate base. Phosphate bases showed better results than carbonate bases in terms of lower basicity. tert-Butanol solvent used as a reaction media played another critical role in nucleophilic [{sup 18}F]fluorination by suppressing eliminated side product. Consequent [{sup 18}F]fluorination under the present condition afforded fast preparation of reaction solution and high radiochemical yields (98% radio-TLC, 84% RCY) with 94% of precursor remained.

In Vitro Inhibition of Enamel Demineralisation by Fluoride-releasing Restorative Materials and Dental Adhesives.

Science.gov (United States)

Dionysopoulos, Dimitrios; Koliniotou-Koumpia, Eugenia; Helvatzoglou-Antoniades, Maria; Kotsanos, Nikolaos

2016-01-01

To determine the ability of 5 contemporary fluoride-releasing restoratives and 3 fluoride-releasing adhesives to inhibit enamel demineralisation surrounding restorations, and the associations between inhibition and the levels of fluoride released from these materials. Five fluoride-releasing restoratives (Fuji IX GP, Ketac N100, Dyract Extra, Beautifil II and Wave) and 3 fluoride-releasing adhesives (Stae, Prime & Bond NT and Fluoro Bond II) were investigated. Eight disks of each material were prepared. Fluoride release was measured daily using a fluoride-ion-selective electrode for 15 days. Twenty-four cavities for each group were restored with a restorative and an adhesive. Specimens were subjected to thermal stress and stored for 30 days in saline solution. After a 15-day pH-cycling regimen, two 150-μm-thick sections were derived from each specimen. Enamel lesion depth was measured at 0, 100, and 200 μm from each restoration's margin via polarised light microscopy. Of the restoratives investigated, Fuji IX GP released the most fluoride. The fluoride-releasing restoratives tested exhibited shallower enamel lesions than did the control group at all distances tested (p < 0.05). Fuji IX GP yielded significantly lower enamel lesion depth than did the other experimental materials. The depths of enamel lesions did not differ significantly when comparing restoratives applied with a fluoride-releasing adhesive with those applied with a non-fluoride-releasing adhesive. The fluoride-releasing materials tested reduced enamel demineralisation but to different extents, depending on their levels of fluoride release. Fluoride-releasing adhesives did not influence enamel lesion formation.

No Calcium-Fluoride-Like Deposits Detected in Plaque Shortly after a Sodium Fluoride Mouthrinse

OpenAIRE

Vogel, G.L.; Tenuta, L.M.A.; Schumacher, G.E.; Chow, L.C.

2010-01-01

Plaque ‘calcium-fluoride-like’ (CaF2-like) and fluoride deposits held by biological/bacterial calcium fluoride (Ca-F) bonds appear to be the source of cariostatic concentrations of fluoride in plaque fluid. The aim of this study was to quantify the amounts of plaque fluoride held in these reservoirs after a sodium fluoride rinse. 30 and 60 min after a 228 μg/g fluoride rinse, plaque samples were collected from 11 volunteers. Each sample was homogenized, split into 2 aliquots (aliquots 1 and 2...

Urinary fluoride output in children following the use of a dual-fluoride varnish formulation

Directory of Open Access Journals (Sweden)

Kelly Polido Kaneshiro Olympio

2009-06-01

Full Text Available OBJECTIVE: This study evaluated the bioavailability of fluoride after topical application of a dual-fluoride varnish commercially available in Brazil, when compared to DuraphatTM. MATERIAL AND METHODS: The urinary fluoride output was evaluated in seven 5-year-old children after application of the fluoride varnishes, in two different phases. In the first phase (I, children received topical application of the fluoride varnish Duofluorid XII (2.92% fluorine, calcium fluoride + 2.71% fluorine, sodium fluoride, FGM TM. After 1-month interval (phase II, the same amount (0.2 mL of the fluoride varnish Duraphat (2.26% fluorine, sodium fluoride, ColgateTM was applied. Before each application all the volunteers brushed their teeth with placebo dentifrice for 7 days. Urinary collections were carried out 24 h prior up to 48 h after the applications. Fluoride intake from the diet was also estimated. Fluoride concentration in diet samples and urine was analyzed with the fluoride ion-specific electrode and a miniature calomel reference electrode coupled to a potentiometer. Data were tested by ANOVA and Tukey's post hoc test (p<0.05. RESULTS: There were significant differences in the urinary fluoride output between phases I and II. The use of Duofluorid XII did not significantly increase the urinary fluoride output, when compared to baseline levels. The application of Duraphat caused a transitory increase in the urinary fluoride output, returning to baseline levels 48 h after its use. CONCLUSIONS: The tested varnish formulation, which has been shown to be effective in in vitro studies, also can be considered safe.

Preparation for Working Readiness Vocational Education Graduate with Self-Concept and Self-Efficacy Development

Directory of Open Access Journals (Sweden)

Novi Trisnawati

2017-09-01

Full Text Available This article aims to examine the efforts that need to be done in facing the readiness of the working world for vocational education by developing self-concept and self efficacy. The increasingly intense work competition in the current era makes vocational education graduates should prepare themselves to be better prepared in facing the world of work. This is done by developing self-concept that can be formed through the planting of strong religious values, self-confidence, self-acceptance. The more we have a positive self-concept then success will be as expected. Self-efficacy is a physiological and emotional condition, expected to increase the ability to work and adapt to the work environment more easily, because self efficacy shows the implementation of processes that have been done during the previous learning process.

Fluoride sorption using Cynodon dactylon based activated carbon

Directory of Open Access Journals (Sweden)

Alagumuthu G.

2011-01-01

Full Text Available This study deals the application of Cynodon dactylon based thermally activated carbon for fluoride toxicity. The batch adsorption techniques was followed at neutral pH as the functions of contact time, adsorbent dose, adsorbate concentration, temperature and the effect of co-anions. The data indicate that the prepared adsorbent surface sites are heterogeneous in nature and that fits into a heterogeneous site-binding model. The present system followed the Redlich-Peterson isotherm as well as Langmuir adsorption isotherm model. Lagergren pseudo-first-order, pseudo-second-order, intra particle diffusion and Elovich kinetics were modeled to describe the adsorption rate of fluoride and determined as this scheme followed pseudo-second-order kinetics. The calculated enthalpy change, ΔH°, and entropy change, ΔS°, for the adsorption process are +8.725 kJ/mol and +0.033 J/mol K respectively and shows endothermic experience. Instrumental analysis of XRD, FTIR and SEM gives the idea about the fluoride binding ability of adsorbent.

Technetium-99m labeled radiodiagnostic agents for liver and bone marrow scanning and method of preparation

International Nuclear Information System (INIS)

Molinski, V.J.; Peacock, F.R.

1977-01-01

An improved technetium-99m labeled colloid and method of preparation comprising reducing technetium-99m with stannous oxalate and stabilizing with sodium phytate are described. This radiodiagnostic agent is useful in the scintigraphic examination of the reticuloendothelial system, particularly the liver. In addition, by autoclaving this product with saline, it becomes a superior bone marrow scanning agent

Fluoride Rinses, Gels and Foams

DEFF Research Database (Denmark)

Twetman, Svante; Keller, Mette K

2016-01-01

AIM: The aim of this conference paper was to systematically review the quality of evidence and summarize the findings of clinical trials published after 2002 using fluoride mouth rinses, fluoride gels or foams for the prevention of dental caries. METHODS: Relevant papers were selected after...... (6 on fluoride mouth rinse, 10 on fluoride gel and 3 on fluoride foam); 6 had a low risk of bias while 2 had a moderate risk. All fluoride measures appeared to be beneficial in preventing crown caries and reversing root caries, but the quality of evidence was graded as low for fluoride mouth rinse......, moderate for fluoride gel and very low for acidulated fluoride foam. No conclusions could be drawn on the cost-effectiveness. CONCLUSIONS: This review, covering the recent decade, has further substantiated the evidence for a caries-preventive effect of fluoride mouth rinse, fluoride gel and foam...

Fluoride exposure of East African consumers using alkaline salt deposits known as magadi (trona) as a food preparation aid

DEFF Research Database (Denmark)

Nielsen, Joan Maj; Dahi, E.

2002-01-01

that the fluoride content varied significantly even for magadi originating from the individual lake, e. g. the fluoride content in magadi from Lake Magadi was between 0.1 and 8.7 mg g(-1). In a lump of magadi originating from Lake Magadi, it was found that the fluoride content in 20 smaller part samples was subject...

Application of Electrocoagulation Process Using Iron and Aluminum Electrodes for Fluoride Removal from Aqueous Environment

Directory of Open Access Journals (Sweden)

Edris Bazrafshan

2012-01-01

Full Text Available Fluoride in drinking water above permissible level is responsible for human being affected by skeletal fluorosis. The present study was carried out to assess the ability of electrocoagulation process with iron and aluminum electrodes in order to removal of fluoride from aqueous solutions. Several working parameters, such as fluoride concentration, pH, applied voltage and reaction time were studied to achieve a higher removal capacity. Variable concentrations (1, 5 and 10 mg L-1 of fluoride solutions were prepared by mixing proper amount of sodium fluoride with deionized water. The varying pH of the initial solution (3, 7 and 10 was also studied to measure their effects on the fluoride removal efficiency. Results obtained with synthetic solution revealed that the most effective removal capacities of fluoride could be achieved at 40 V electrical potential. In addition, the increase of electrical potential, in the range of 10-40 V, enhanced the treatment rate. Also comparison of fluoride removal efficiency showed that removal efficiency is similar with iron and aluminum electrodes. Finally it can be concluded that the electrocoagulation process has the potential to be utilized for the cost-effective removal of fluoride from water and wastewater.

The cariostatic mechanisms of fluoride

Directory of Open Access Journals (Sweden)

Kata Rošin-Grget

2013-11-01

Full Text Available This article discusses the possible cariostatic mechanisms of the action of fluoride. In the past, fluoride inhibition of caries was ascribed to reduced solubility of enamel due to incorporation of fluoride (F– into the enamel minerals. The present evidence from clinical and laboratory studies suggests that the caries-preventive mode of action of fluoride is mainly topical. There is convincing evidence that fluoride has a major effect on demineralisation and remineralisation of dental hard tissue. The source of this fluoride could either be fluorapatite (formed due to the incorporation of fluoride into enamel or calcium fluoride (CaF2-like precipitates, which are formed on the enamel and in the plaque after application of topical fluoride. Calcium fluoride deposits are protected from rapid dissolution by a phosphate –protein coating of salivary origin. At lower pH, the coating is lost and an increased dissolution rate of calcium fluoride occurs. The CaF2, therefore, act as an efficient source of free fluoride ions during the cariogenic challenge. The current evidence indicates that fluoride has a direct and indirect effect on bacterial cells, although the in vivo implications of this are still not clear. Conclusion. A better understanding of the mechanisms of the action of fluoride is very important for caries prevention and control. The effectiveness of fluoride as a cariostatic agent depends on the availability of free fluoride in plaque during cariogenic challenge, i.e. during acid production. Thus, a constant supply of low levels of fluoride in biofilm/saliva/dental interference is considered the most beneficial in preventing dental caries.

The cariostatic mechanisms of fluoride.

Science.gov (United States)

Rošin-Grget, Kata; Peroš, Kristina; Sutej, Ivana; Bašić, Krešimir

2013-11-01

This article discusses the possible cariostatic mechanisms of the action of fluoride. In the past, fluoride inhibition of caries was ascribed to reduced solubility of enamel due to incorporation of fluoride (F-) into the enamel minerals. The present evidence from clinical and laboratory studies suggests that the caries-preventive mode of action of fluoride is mainly topical. There is convincing evidence that fluoride has a major effect on demineralisation and remineralisation of dental hard tissue. The source of this fluoride could either be fluorapatite (formed due to the incorporation of fluoride into enamel) or calcium fluoride (CaF2)-like precipitates, which are formed on the enamel and in the plaque after application of topical fluoride. Calcium fluoride deposits are protected from rapid dissolution by a phosphate -protein coating of salivary origin. At lower pH, the coating is lost and an increased dissolution rate of calcium fluoride occurs. The CaF2, therefore, act as an efficient source of free fluoride ions during the cariogenic challenge. The current evidence indicates that fluoride has a direct and indirect effect on bacterial cells, although the in vivo implications of this are still not clear. A better understanding of the mechanisms of the action of fluoride is very important for caries prevention and control. The effectiveness of fluoride as a cariostatic agent depends on the availability of free fluoride in plaque during cariogenic challenge, i.e. during acid production. Thus, a constant supply of low levels of fluoride in biofilm/saliva/dental interference is considered the most beneficial in preventing dental caries. Copyright © 2013 by Academy of Sciences and Arts of Bosnia and Herzegovina.

Experimental facilities for research of properties and behaviour of fluoride salts

International Nuclear Information System (INIS)

Hosnedl, P.; Jilek, M.; Kroc, V.; Pedal, L.; Valenta, V.; Vodicka, J.

1999-01-01

SKODA JS s.r.o. (Czech leading nuclear technology manufacturer) prepared and manufactured experimental loops for research and verification of properties and behaviour of fluoride salts for primary and secondary circuit, construction materials and ADTT systems technological components for the operation in the Nuclear Research Institute Rez plc fluorine chemistry laboratory. This paper presents charts and experimental program for molten fluoride salts experimental loops with natural circulation. Further on, the paper describes extension of the loops for research with forced circulation and next works for steam generator model verification and connection with the loop of Energovyzkum Brno. The loops are designed and constructed to obtain a sufficient amount of experience on ADTT technology. The research and utilisation program covers questions of corrosion and intergranular corrosion of structural materials, research of material properties and welding, research of fluoride fluid properties, measuring of thermo-hydraulic properties of molten salt fluoride fluids, heat transfer and hydraulics, development and tests of some plant components (steam generators, heat exchangers, pumps, valves) and other engineering issues. Two electrolyzers have been manufactured for the research of fuel/coolant fluoride salts mixture purification. One for the production of hydrogen fluoride, and the other for the research of salts purification. (author)

Fluoride and Oral Health.

Science.gov (United States)

O'Mullane, D M; Baez, R J; Jones, S; Lennon, M A; Petersen, P E; Rugg-Gunn, A J; Whelton, H; Whitford, G M

2016-06-01

The discovery during the first half of the 20th century of the link between natural fluoride, adjusted fluoride levels in drinking water and reduced dental caries prevalence proved to be a stimulus for worldwide on-going research into the role of fluoride in improving oral health. Epidemiological studies of fluoridation programmes have confirmed their safety and their effectiveness in controlling dental caries. Major advances in our knowledge of how fluoride impacts the caries process have led to the development, assessment of effectiveness and promotion of other fluoride vehicles including salt, milk, tablets, toothpaste, gels and varnishes. In 1993, the World Health Organization convened an Expert Committee to provide authoritative information on the role of fluorides in the promotion of oral health throughout the world (WHO TRS 846, 1994). This present publication is a revision of the original 1994 document, again using the expertise of researchers from the extensive fields of knowledge required to successfully implement complex interventions such as the use of fluorides to improve dental and oral health. Financial support for research into the development of these new fluoride strategies has come from many sources including government health departments as well as international and national grant agencies. In addition, the unique role which industry has played in the development, formulation, assessment of effectiveness and promotion of the various fluoride vehicles and strategies is noteworthy. This updated version of 'Fluoride and Oral Health' has adopted an evidence-based approach to its commentary on the different fluoride vehicles and strategies and also to its recommendations. In this regard, full account is taken of the many recent systematic reviews published in peer reviewed literature.

Fluoride removal from double four-membered ring (D4R) units in As-synthesized Ge-containing zeolites

KAUST Repository

Liu, Xiaolong; Ravon, Ugo; Tuel, Alain

2011-01-01

Fluoride anions can be removed from the framework of as-prepared Ge-containing zeolites ITQ-13 and ITQ-17 without modification of the crystallinity and crystal habit. By contrast to all-silica ITQ-13 for which fluoride could not get out from D4R

Whole mouth antimicrobial effects after oral hygiene: comparison of three dentifrice formulations.

Science.gov (United States)

Fine, Daniel H; Sreenivasan, Prem K; McKiernan, Marie; Tischio-Bereski, Debra; Furgang, David

2012-11-01

This study compared the antimicrobial effects of three commercial dentifrice formulations: sodium fluoride/triclosan/copolymer (TCN/C), stannous fluoride/sodium hexametaphosphate/zinc lactate (SnF(2)/SHMP) and sodium fluoride (NaF). Thirty-five adults (15 men and 20 women; average age 33 years and pockets oral sites and six organisms evaluated in each site, the TCN/C demonstrated significant reductions (49-83%) as compared with the other treatments (p oral sites in comparison with the NaF, or the SnF(2)/SHMP dentifrice formulations as seen 12 h after brushing. © 2012 John Wiley & Sons A/S.

Highly selective single-use fluoride ion optical sensor based on aluminum(III)-salen complex in thin polymeric film

International Nuclear Information System (INIS)

Badr, Ibrahim H.A.; Meyerhoff, Mark E.

2005-01-01

A highly selective optical sensor for fluoride ion based on the use of an aluminum(III)-salen complex as an ionophore within a thin polymeric film is described. The sensor is prepared by embedding the aluminum(III)-salen ionophore and a suitable lipophilic pH-sensitive indicator (ETH-7075) in a plasticized poly(vinyl chloride) (PVC) film. Optical response to fluoride occurs due to fluoride extraction into the polymer via formation of a strong complex with the aluminum(III)-salen species. Co-extraction of protons occurs simultaneously, with protonation of the indicator dye yielding the optical response at 529 nm. Films prepared using dioctylsebacate (DOS) are shown to exhibit better response (e.g., linear range, detection limit, and optical signal stability) compared to those prepared using ortho-nitrophenyloctyl ether (o-NPOE). Films formulated with aluminum(III)-salen and ETH-7075 indicator in 2 DOS:1 PVC, exhibit a significantly enhanced selectivity for fluoride over a wide range of lipophilic anions including salicylate, perchlorate, nitrate, and thiocyanate. The optimized films exhibit a sub-micromolar detection limit, using glycine-phosphate buffer, pH 3.00, as the test sample. The response times of the fluoride optical sensing films are in the range of 1-10 min depending on the fluoride ion concentration in the sample. The sensor exhibits very poor reversibility owing to a high co-extraction constant (log K = 8.5 ± 0.4), indicating that it can best be employed as a single-use transduction device. The utility of the aluminum(III)-salen based fluoride sensitive films as single-use sensors is demonstrated by casting polymeric films on the bottom of standard polypropylene microtiter plate wells (96 wells/plate). The modified microtiter plate optode format sensors exhibit response characteristics comparable to the classical optode films cast on quartz slides. The modified microtiter is utilized for the analysis of fluoride in diluted anti-cavity fluoride rinse

Fluoride level in saliva after bonding orthodontic brackets with a fluoride containing adhesive

NARCIS (Netherlands)

Ogaard, B; Arends, J; Helseth, H; Dijkman, G; vanderKuijl, M

The fluoride level in saliva is considered an important parameter in caries prevention. Elevation of the salivary fluoride level by a fluoride-releasing orthodontic bonding adhesive would most likely be beneficial in the prevention of enamel caries. In this study, the fluoride level in saliva was

Data on daily fluoride intake based on drinking water consumption prepared by household desalinators working by reverse osmosis process.

Science.gov (United States)

Karbasdehi, Vahid Noroozi; Dobaradaran, Sina; Esmaili, Abdolhamid; Mirahmadi, Roghayeh; Ghasemi, Fatemeh Faraji; Keshtkar, Mozhgan

2016-09-01

In this data article, we evaluated the daily fluoride contents in 20 household desalinators working by reverse osmosis (RO) process in Bushehr, Iran. The concentration levels of fluoride in inlet and outlet waters were determined by the standard SPADNS method using a spectrophotometer (M501 Single Beam Scanning UV/VIS, UK). The fluoride content in outlet waters were compared with EPA and WHO guidelines for drinking water.

Preparation and quality control of ECD kit

International Nuclear Information System (INIS)

Yassin, T.; Dadokh, M.; Almalki, R.

2005-05-01

ECD Kit for brain imaging after labeling with technetium 99m was prepared according to an optimum conditions, Each vial contains 1 mg of ECD and 0.155 mg of stannous chloride anhydrous SnCl 2 , 24 mg of Mannitol and 0.5 mg of Na 2 Ca EDTA, The prepared kit showed high quality satisfying the requirements of international pharmacopoeias from the points of physical, chemical, radiochemical and biological purities, and its validity for human injection. And the labeling yield exceeded 95 % with average value of about 97.63 ± 0.89% for 2mCi /2ml radioactivity , This study also showed that each vial content can be labeled with maximum activity of 99m Tc of about 50 mCi (Authors)

Fluoride glass fiber optics

CERN Document Server

Aggarwal, Ishwar D

1991-01-01

Fluoride Glass Fiber Optics reviews the fundamental aspects of fluoride glasses. This book is divided into nine chapters. Chapter 1 discusses the wide range of fluoride glasses with an emphasis on fluorozirconate-based compositions. The structure of simple fluoride systems, such as BaF2 binary glass is elaborated in Chapter 2. The third chapter covers the intrinsic transparency of fluoride glasses from the UV to the IR, with particular emphasis on the multiphonon edge and electronic edge. The next three chapters are devoted to ultra-low loss optical fibers, reviewing methods for purifying and

A simple and colorimetric fluoride receptor and its fluoride-responsive organogel

Energy Technology Data Exchange (ETDEWEB)

Yu Xudong, E-mail: 081022009@fudan.edu.cn [College of Science, Hebei University of Science and Technology, Yuhua Road 70, Shijiazhuang 050080 (China); Li Yajuan [College of Science, Hebei University of Science and Technology, Yuhua Road 70, Shijiazhuang 050080 (China); Yin Yaobing; Yu Decai [College of Science, Hebei University of Engineering, 199 South street of Guangming, Handan 056038 (China)

2012-08-01

In this paper, a new p-nitrophenylhydrozine-based anion receptor 1 containing cholesterol group had been designed and synthesized. It could selectively recognize fluoride among different anions tested with color changes from pale yellow to red for visual detection. Simultaneously, it could gel in cyclohexane, and the gel was also fluoride-responsive. When treated with TBAF (tetra-n-butylammonium fluoride), the gel could undergo gel-sol transition accompanied by color, morphology and surface changes. The binding mechanism had been investigated by UV-vis and {sup 1}HNMR (proton nuclear magnetic resonance spectra) titrations. From SEM (scanning electron microscope), SAXS (small-angle X-ray scattering), IR (Infrared Spectroscopy) and CA (contact angle) experiments, it was indicated that the addition of F{sup -} could destroy the molecule assembly of host 1 in the gel state, thus resulting in the gel-to-sol transition due to the binding site competition effect. To the best of our knowledge, this was the simplest fluoride-responsive organogel with high selectivity. Highlights: Black-Right-Pointing-Pointer A novel kind receptor for selective recognition of fluoride had been designed. Black-Right-Pointing-Pointer Its organogel was also fluoride-responsive. Black-Right-Pointing-Pointer This is the simplest fluoride-responsive organogel with high selectivity.

Fluoride metabolism in plants

Energy Technology Data Exchange (ETDEWEB)

Peters, R; Shorthouse, M

1964-04-04

Grass seedlings exposed to inorganic fluoride solutions do not take up appreciable amounts of fluoride until concentrations of more than 1.0 mM (19 p.p.m.) are used. No formation of organic fluoride has been found, even with exposure to 15.75 mM fluoride, indicating that there is no formation of fluoroacetate or similar compounds. 8 references, 2 tables.

Bottled Water and Fluoride

Science.gov (United States)

... Private Wells Infant Formula Fluorosis Public Health Service Recommendation Water Operators & Engineers Water Fluoridation Additives Shortages of Fluoridation Additives Drinking Water Pipe Systems CDC-Sponsored Water Fluoridation Training Links to Other ...

Benign and efficient preparation of thioethers by solvent-free S-alkylation of thiols with alkyl halides catalyzed by potassium fluoride on alumina

DEFF Research Database (Denmark)

Nguyen, Kha Ngoc; Duus, Fritz; Luu, Thi Xuan Thi

2016-01-01

The preparation of thioethers by S-alkylation of various thiols with alkyl halides under solvent-free reaction conditions using potassium fluoride on alumina (KF/Al2O3) as a solid catalyst has been investigated in detail with respect to three different modes of reaction activation (ultrasound...... irradiation, microwave irradiation, and conventional heating) for obtaining maximum yield of the thioether. The importance of KF/Al2O3 as a particularly efficient catalyst was corroborated for all three modes of reaction activation, although the reaction time was found to be strongly dependent on the mode...

Thermodynamic data for uranium fluorides

Energy Technology Data Exchange (ETDEWEB)

Leitnaker, J.M.

1983-03-01

Self-consistent thermodynamic data have been tabulated for uranium fluorides between UF/sub 4/ and UF/sub 6/, including UF/sub 4/ (solid and gas), U/sub 4/F/sub 17/ (solid), U/sub 2/F/sub 9/ (solid), UF/sub 5/ (solid and gas), U/sub 2/F/sub 10/ (gas), and UF/sub 6/ (solid, liquid, and gas). Included are thermal function - the heat capacity, enthalpy, and free energy function, heats of formation, and vaporization behavior.

Effect of a 5000 ppm fluoride toothpaste and a 250 ppm fluoride mouth rinse on the demineralisation of dentin surfaces.

Science.gov (United States)

Bizhang, Mozhgan; Chun, Yong-Hee P; Winterfeld, Mai-Trinh; Altenburger, Markus J; Raab, Wolfgang H M; Zimmer, Stefan

2009-07-23

The purpose of this study was to test the null hypothesis that there is no difference between the effect of (1) a 5000 ppm fluoride toothpaste, and (2) a 250 ppm fluoride mouth rinse on demineralized human dentin surfaces, against the alternative hypothesis of a difference. Dentin specimens were obtained from the cervical regions of 45 extracted human third molars. Half the surface of each specimen was sealed with a self-etching adhesive system and served as the reference surface. The dentin specimens were randomly assigned to one of the three groups, 5000 ppm fluoride toothpaste (Duraphat), 250 ppm fluoride mouth rinse (Meridol) and distilled water (negative control).An intraoral appliance was made for one volunteer. In each test cycle, 15 specimens were inserted in the appliance and worn for 24 hours a day, over a period of three weeks.Once daily, the appliance was immersed in the agent being tested; either toothpaste slurry, mouth rinse or distilled water for 60 seconds.Demineralization was assessed in terms of lesion depth (microm) and mineral loss (vol. % x microm) by transversal microradiography. Data analysis was accomplished using Kolmogorov-Smirnov test and ANOVA (SPSS 12.0).Statistically significant differences for mineral loss and lesion depth were found between the toothpaste and the mouth rinse as well as between the toothpaste and the control group, but not between the mouth rinse and the control group. Within the limitations of this study, the results suggest that treatment of demineralised dentin with a toothpaste containing 5000 ppm fluoride may considerably reduce mineral loss and lesion depth on exposed dentin.

Synthesis and properties of a high-capacity iron oxide adsorbent for fluoride removal from drinking water

Science.gov (United States)

Zhang, Chang; Li, Yingzhen; Wang, Ting-Jie; Jiang, Yanping; Fok, Jason

2017-12-01

A novel iron oxide adsorbent with a high fluoride adsorption capacity was prepared by a facile wet-chemical precipitation method and ethanol treatment. The ethanol-treated adsorbent was amorphous and had a high specific surface area. The adsorption capacity of the treated adsorbent was much higher than that of untreated adsorbent. The Langmuir maximum adsorption capacity of the adsorbent prepared at a low final precipitation pH (≤9.0) and treated with ethanol reached 60.8 mg/g. A fast adsorption rate was obtained, and 80% of the adsorption equilibrium capacity was achieved within 2 min. The adsorbent had high fluoride-removal efficiency for water in a wide initial pH range of 3.5-10.3 and had a high affinity for fluoride in the presence of common co-anions. The ethanol treatment resulted in structure transformation of the adsorbent by inhibiting the crystallization of the nano-precipitates. The adsorption was confirmed to be ion exchange between fluoride ions and the hydroxyl groups on the adsorbent surface.

Simultaneous Assessment of Acidogenesis-Mitigation and Specific Bacterial Growth-Inhibition by Dentifrices.

Directory of Open Access Journals (Sweden)

Sarah Forbes

Full Text Available Dentifrices can augment oral hygiene by inactivating bacteria and at sub-lethal concentrations may affect bacterial metabolism, potentially inhibiting acidogenesis, the main cause of caries. Reported herein is the development of a rapid method to simultaneously measure group-specific bactericidal and acidogenesis-mitigation effects of dentifrices on oral bacteria. Saliva was incubated aerobically and anaerobically in Tryptone Soya Broth, Wilkins-Chalgren Broth with mucin, or artificial saliva and was exposed to dentifrices containing triclosan/copolymer (TD; sodium fluoride (FD; stannous fluoride and zinc lactate (SFD1; or stannous fluoride, zinc lactate and stannous chloride (SFD2. Minimum inhibitory concentrations (MIC were determined turbidometrically whilst group-specific minimum bactericidal concentrations (MBC were assessed using growth media and conditions selective for total aerobes, total anaerobes, streptococci and Gram-negative anaerobes. Minimum acid neutralization concentration (MNC was defined as the lowest concentration of dentifrice at which acidification was inhibited. Differences between MIC and MNC were calculated and normalized with respect to MIC to derive the combined inhibitory and neutralizing capacity (CINC, a cumulative measure of acidogenesis-mitigation and growth inhibition. The overall rank order for growth inhibition potency (MIC under aerobic and anaerobic conditions was: TD> SFD2> SFD1> FD. Acidogenesis-mitigation (MNC was ordered; TD> FD> SFD2> SFD1. CINC was ordered TD> FD> SFD2> SFD1 aerobically and TD> FD> SFD1> SFD2 anaerobically. With respect to group-specific bactericidal activity, TD generally exhibited the greatest potency, particularly against total aerobes, total anaerobes and streptococci. This approach enables the rapid simultaneous evaluation of acidity mitigation, growth inhibition and specific antimicrobial activity by dentifrices.

Fluoride release and recharge abilities of contemporary fluoride-containing restorative materials and dental adhesives.

Science.gov (United States)

Dionysopoulos, Dimitrios; Koliniotou-Koumpia, Eugenia; Helvatzoglou-Antoniades, Maria; Kotsanos, Nikolaos

2013-01-01

The aim of this study was to evaluate the fluoride release of five fluoride-releasing restorative materials and three dental adhesives, before and after NaF solution treatment. Five restorative materials (Fuji IX GP, GC Corp.; Ketac N100, 3M ESPE; Dyract Extra, Dentsply; Beautifil II, Shofu Inc.; Wave, SDI) and three dental adhesives (Stae, SDI; Fluorobond II - Shofu Inc.; Prime & Bond NT, Dentsply) were investigated before and after NaF solution treatment. A fluoride ion-selective electrode was to measure fluoride concentrations. During the 86-day period before NaF solution treatment, Fuji IX GP released the highest amount of fluoride among the restorative materials while Prime & Bond NT was the highest among the dental adhesives. After NaF solution treatment, Fuji IX GP again ranked the highest in fluoride release among the restorative materials while Fluorobond II ranked the highest among dental adhesives. It was concluded that the compositions and setting mechanisms of fluoride-containing dental materials influenced their fluoride release and recharge abilities.

No calcium-fluoride-like deposits detected in plaque shortly after a sodium fluoride mouthrinse.

Science.gov (United States)

Vogel, G L; Tenuta, L M A; Schumacher, G E; Chow, L C

2010-01-01

Plaque 'calcium-fluoride-like' (CaF(2)-like) and fluoride deposits held by biological/bacterial calcium fluoride (Ca-F) bonds appear to be the source of cariostatic concentrations of fluoride in plaque fluid. The aim of this study was to quantify the amounts of plaque fluoride held in these reservoirs after a sodium fluoride rinse. 30 and 60 min after a 228 microg/g fluoride rinse, plaque samples were collected from 11 volunteers. Each sample was homogenized, split into 2 aliquots (aliquots 1 and 2), centrifuged, and the recovered plaque fluid combined and analyzed using microelectrodes. The plaque mass from aliquot 1 was retained. The plaque mass from aliquot 2 was extracted several times with a solution having the same fluoride, calcium and pH as the plaque fluid in order to extract the plaque CaF(2)-like deposits. The total fluoride in both aliquots was then determined. In a second experiment, the extraction completeness was examined by applying the above procedure to in vitro precipitates containing known amounts of CaF(2)-like deposits. Nearly identical fluoride concentrations were found in both plaque aliquots. The extraction of the CaF(2)-like precipitates formed in vitro removed more than 80% of these deposits. The results suggest that either CaF(2)-like deposits were not formed in plaque or, if these deposits had been formed, they were rapidly lost. The inability to form persistent amounts of CaF(2)-like deposits in plaque may account for the relatively rapid loss of plaque fluid fluoride after the use of conventional fluoride dentifrices or rinses. (c) 2010 S. Karger AG, Basel.

Fluoride concentration in urine after silver diamine fluoride application on tooth enamel

Science.gov (United States)

Sari, D. L.; Bahar, A.; Gunawan, H. A.; Adiatman, M.; Rahardjo, A.; Maharani, D. A.; Toptanci, I. R.; Yavuz, I.

2017-08-01

Silver Diammine Fluoride (SDF), which contains fluoride, is known to inhibit tooth enamel demineralization and increase fluoride concentrations in saliva and urine. The aim of this study is to analyze the fluoride concentration in urine after application of SDF on tooth enamel. Urine from four subjects was collected prior to, 30 minutes after, and two and three hours after the application of SDF, and an ion-selective electrode was used to measure the fluoride concentrations. There was no significant difference between time 1 and time 2, time 1 and time 3, time 1 and time 4, time 2 and 3 (p > 0.05), and there was a significant difference between time 2 and time 4 as well as time 3 and time 4 (p < 0.05). There was a decrease in the concentration of fluoride ions in urine from the baseline to 30 minutes after application, and an increase from baseline to two and three hours after the application of SDF.

Application of a new adsorbent for fluoride removal from aqueous solutions

International Nuclear Information System (INIS)

Srivastav, Arun Lal; Singh, Prabhat K.; Srivastava, Varsha; Sharma, Yogesh C.

2013-01-01

Highlights: • A new adsorbent has been prepared. • The adsorbent is non-toxic and easy to synthesize. • HBO 1 has displayed best capacity for the removal of fluoride. • Unlike most adsorbents, HBO 1 is suitable for the removal of fluoride from water. • The process of removal has been optimized. -- Abstract: Hydrous bismuth oxides (HBOs) have been investigated as a possible adsorbent for fluoride removal from water. Apart from bismuth trioxide (Bi 2 O 3 ) compound, three additional HBOs, named as HBO 1 , HBO 2 , and HBO 3 were synthesized in the laboratory and examined for their relative potentials for fluoride removal from aqueous solutions. HBO 1 was observed to have highest fluoride removal at 10 mg/L initial concentration in aqueous environment. Among competitive anions, sulfate and chloride affect the fluoride removal by HBO 1 more adversely than bicarbonate. Characterization of HBOs using X-ray diffraction (XRD) pattern analyses indicated crystalline structures, and the broad chemical composition of materials showed successive increase of Bi(OH) 3 from HBO 1 to HBO 3 , with decrease of BiOCl in the same order. Fourier Transform Infrared (FTIR) spectroscopy analyses indicated presence of Bi-O bond and successively increasing number of peaks corresponding to OH ion from HBO 1 to HBO 3 . Scanning Electron Microscopic (SEM) images of HBOs show rough and porous structure of the materials. Presence of higher proportion of chloride compound in HBO 1 with respect to others appears to be the factor responsible for its better performance in fluoride removal from aqueous solutions

Water Fluoridation Statistics - Percent of PWS population receiving fluoridated water

Data.gov (United States)

U.S. Department of Health & Human Services — 2000-2014. Water Fluoridation Statistics is a biennial report of the percentage and number of people receiving fluoridated water from 2000 through 2014, originally...

Water Fluoridation Statistics - Percent of PWS population receiving fluoridated water

Data.gov (United States)

U.S. Department of Health & Human Services — 2000-2014 Water Fluoridation Statistics is a biennial report of the percentage and number of people receiving fluoridated water from 2000 through 2014, originally...

Fluoride releasing and enamel demineralization around orthodontic brackets by fluoride-releasing composite containing nanoparticles.

Science.gov (United States)

Melo, Mary A S; Morais, Weslanny A; Passos, Vanara F; Lima, Juliana P M; Rodrigues, Lidiany K A

2014-05-01

Fluoride-containing materials have been suggested to control enamel demineralization around orthodontic brackets during the treatment with fixed appliances. The improvement of their properties has been made through innovations, such as the application of nanotechnology by incorporation of nanofillers. This in vitro study evaluated the capacity of fluoride releasing and enamel demineralization inhibition of fluoride-releasing nanofilled cement around orthodontic brackets using an artificial caries biofilm model. Forty bovine enamel discs were selected by evaluating surface microhardness and randomized into four groups (n = 10): non-fluoride-releasing microfilled composite, fluoride-releasing microfilled composite, resin-modified glass ionomer cement (RMGI), and fluoride-releasing nanofilled composite (FN). After brackets bonding in each disc, the specimens were subjected to a cariogenic challenge through a Streptococcus mutans biofilm model. After the experimental period, the biofilm formed around the brackets was collected for fluoride analysis and the mineral loss around the brackets was determined by integrated demineralization via cross-sectional microhardness measurement at 20 and 70 μm from the bracket margin. Additionally, samples of each group were subjected to energy-dispersive X-ray spectroscopy (EDX) analysis examined under a scanning electron microscopy (SEM). ANOVA followed by Tukey test were applied for fluoride concentration and mineral loss data, respectively. At both distances, only RMGI statistically differed from the other groups presenting the lowest demineralization, although there was a trend to a lower demineralization of enamel around brackets in FN group. Similar condition was found to fluoride concentration and EDX/SEM analysis. Under the cariogenic exposure condition of this study, the fluoride-releasing nanofilled material had similar performance to fluoride-releasing microfilled materials. The presence of nanofillers in the fluoride

Synthesis of alkynes from vinyl triflates using tetrabutylammonium fluoride.

Science.gov (United States)

Okutani, Masaru; Mori, Yuji

2015-01-01

A convenient method for the preparation of alkynes and alkynyl esters from ketones and β-keto esters is described which involves the formation of vinyl triflates, followed by elimination with tetrabutylammonium fluoride trihydrate, to give alkynes. Unlike established elimination methods, the method requires neither a strong base nor anhydrous conditions.

Determination of fluoride in spices using microwave induced oxygen combustion

Directory of Open Access Journals (Sweden)

Emanuel Šucman

2012-01-01

Full Text Available Fluorine is essential in human and/or animal nutrition; therefore, so it is important to know its concentration in a diet. One of the possible sources of fluorine for humans is spice, containing various amounts of this trace element. This work describes the method for fluoride determination in various kinds ofspices using microwave-supported sample preparation in high pressure oxygen atmosphere followed by potentiometry with a fluoride ion-selective electrode. Parameters of the microwave device for combustion procedure were checked and optimized in order to find settings ensuring complete sample combustion and/or absorption of the analyte in the absorption solution. For the ion-selective electrode measurement, the technique of standard straight line was chosen. Concentrations of fluorides in spices and spice blends under investigation ranged from 3.15 mg·kg-1 to 26.08 mg·kg-1. In order to check the accuracy of the method Certified Reference Material Fluoride in Vegetation NIST 2695 was used and a good agreement between certified and found values was found. The precision expressed as the relative standard deviation ranged from 0.6% to 5.0%. The method is fast, accurate and reliable for this kind of analysis. In recent literature data on fluoride concentrations in spices and/or spice blends have not been found.

Uptake Fluoride from Water by Starch Stabilized Layered Double Hydroxides

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Jiming Liu

2018-06-01

Full Text Available A novel starch stabilized Mg/Al layered Double hydroxides (S-LDHs was prepared in a facile approach and its fluoride ion removal performance was developed. Characterization of S-LDHs was employed by using X-ray diffraction (XRD, Fourier-transform infrared spectroscopy (FTIR, and particle size distribution. The adsorption property was studied through the assessment of the adsorption isotherms, kinetic models, thermal dynamics, and pH influence. The result shows that a low loading of starch of 10 mg onto layered double hydroxides (LDHs could obviously improve the fluoride removal rate. The S-LDHs had three times higher the adsorption capacity to fluoride than that of Mg/Al LDHs to fluoride. The particle size was smaller and the particle size distribution was narrower for S-LDHs than that for Mg/Al LDHs. The Langmuir adsorption isotherm model and pseudo-second-order kinetic model fitted well with the experimental data. In thermodynamic parameters, the enthalpy (ΔH0 value was 35.63 kJ·mol−1 and the entropy (ΔS0 value was 0.0806 kJ·mol−1K−1. The values of ΔG0 were negative, implying the adsorption process is spontaneous. S-LDHs reveals stable adsorption property in a wide pH range from 3 to 9. The mechanism for fluoride adsorption on S-LDHs included surface adsorption and interaction ion exchange.

Oral fluoride levels 1 h after use of a sodium fluoride rinse: effect of sodium lauryl sulfate.

Science.gov (United States)

Vogel, Gerald L; Schumacher, Gary E; Chow, Laurence C; Tenuta, Livia M A

2015-01-01

Increasing the concentration of free fluoride in oral fluids is an important goal in the use of topical fluoride agents. Although sodium lauryl sulfate (SLS) is a common dentifrice ingredient, the influence of this ion on plaque fluid and salivary fluid fluoride has not been examined. The purpose of this study was to investigate the effect of SLS on these parameters and to examine the effect of this ion on total (or whole) plaque fluoride, an important source of plaque fluid fluoride after a sufficient interval following fluoride administration, and on total salivary fluoride, a parameter often used as a surrogate measure of salivary fluid fluoride. Ten subjects accumulated plaque for 48 h before rinsing with a 12 mmol/l NaF (228 µg/g F) rinse containing or not containing 0.5% (w/w) SLS. SLS had no statistically significant effect on total plaque and total saliva fluoride but significantly increased salivary fluid and plaque fluid fluoride (by 147 and 205%, respectively). These results suggest that the nonfluoride components of topical agents can be manipulated to improve the fluoride release characteristics from oral fluoride reservoirs and that statistically significant change may be observed in plaque fluid and salivary fluid fluoride concentrations that may not be observed in total plaque and total saliva fluoride concentrations.

Are “voluntary” self-employed better prepared for retirement than “forced” self-employed?

NARCIS (Netherlands)

Hershey, D.A.; van Dalen, Harry; Conen, Wieteke; Henkens, Kene

2017-01-01

When it comes to financial preparation for retirement, self-employed workers in many European countries face unique challenges not encountered by traditional wage earners. This is particularly true for self-employed workers because many self-employed individuals do not have large-scale access to

Are “Voluntary” Self-Employed Better Prepared for Retirement Than “Forced” Self-Employed?

NARCIS (Netherlands)

Hershey, D.; van Dalen, H.P.; Conen, W.S.; Henkens, K.

2017-01-01

When it comes to financial preparation for retirement, self-employed workers in many European countries face unique challenges not encountered by traditional wage earners. This is particularly true for self-employed workers because many self-employed individuals do not have large-scale access to

The cariostatic mechanisms of fluoride

OpenAIRE

Kata Rošin-Grget; Kristina Peroš; Ivana Šutej; Krešimir Bašić

2013-01-01

This article discusses the possible cariostatic mechanisms of the action of fluoride. In the past, fluoride inhibition of caries was ascribed to reduced solubility of enamel due to incorporation of fluoride (F–) into the enamel minerals. The present evidence from clinical and laboratory studies suggests that the caries-preventive mode of action of fluoride is mainly topical. There is convincing evidence that fluoride has a major effect on demineralisation and remineralisation of dental hard t...

Small molecule fluoride toxicity agonists.

Science.gov (United States)

Nelson, James W; Plummer, Mark S; Blount, Kenneth F; Ames, Tyler D; Breaker, Ronald R

2015-04-23

Fluoride is a ubiquitous anion that inhibits a wide variety of metabolic processes. Here, we report the identification of a series of compounds that enhance fluoride toxicity in Escherichia coli and Streptococcus mutans. These molecules were isolated by using a high-throughput screen (HTS) for compounds that increase intracellular fluoride levels as determined via a fluoride riboswitch reporter fusion construct. A series of derivatives were synthesized to examine structure-activity relationships, leading to the identification of compounds with improved activity. Thus, we demonstrate that small molecule fluoride toxicity agonists can be identified by HTS from existing chemical libraries by exploiting a natural fluoride riboswitch. In addition, our findings suggest that some molecules might be further optimized to function as binary antibacterial agents when combined with fluoride. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fluoride varnishes and enamel caries

NARCIS (Netherlands)

Bruyn, Hugo de

1987-01-01

Topical fluoride applications have the aim of increasing the fluoride uptake in enamel and consequently reducing caries. In the early ‘60s fluoride varnishes were introduced because they had a long contact period with the enamel which resulted in a higher fluoride uptake than from other topical

[The effects of topical fluoridation of enamel on the growth of cariogenic bacteria contained in the dental plaque].

Science.gov (United States)

Płuciennik-Stronias, Małgorzata; Zarzycka, Beata; Bołtacz-Rzepkowska, Elzbieta

2013-01-01

Dental caries is a bacterial disease. The most important element used in caries prevention is fluoride, which is derived from the air, diet or fluoride-containing preparations and materials, e.g. glass-ionomer restorations. Fluoride can inhibit metabolism and bacterial growth in the dental plaque. The aim of the study was to evaluate the effect of topical fluoridation of the enamel on the growth of Lactobacillus spp. in the dental plaque. The study was carried out in 15 patients with good oral hygiene, in whom three-day dental plaque from the enamel was examined. Next, fluoride was rubbed on the same surface and the examination of three-day dental plaque was repeated. No statistically significant differences (p = 0.475) in the amounts of Lactobacillus spp. in the plaque collected prior to and after the topical fluoridation were revealed. Fluoride rubbed in the enamel, did not affect the amount of Lactobacillus spp. in the dental plaque growing on this material.

Preparation of sup(99m) Tc - L - asparagine

International Nuclear Information System (INIS)

Okada, H.; Silva, C.P.G. da; Pereira, N.P.S. de.

1986-05-01

The interrelationship between technetium-99m, different reducing agents and the L-asparagine is studied. The maximum labelling yield, aboult 95%, is obtained by using the following molar ratios for ligand to reducing agents: L-asparagine: stannous ascorbate, 150:1; the L-asparagine: ascorbic acid, 50:1, and L-asparagine:stannous chloride, 800:1. This radiopharmaceutical is used for visualization of dependent asparagine tumours. (Author) [pt

Daily Fluoride Intake from Iranian Green Tea: Evaluation of Various Flavorings on Fluoride Release

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Afshin Maleki

2016-01-01

Full Text Available With increased awareness of the health benefits of the compounds in green tea, especially polyphenols, its consumption is rising. The main purpose of this study is to determine the effect of different additives on the released fluoride into tea liquor and also daily fluoride intake. The concentrations of fluoride, nitrate, sulfate, and chloride were measured in 15 different flavored green teas (Refah-Lahijan. The fluoride and other anion concentrations were measured by ion chromatography method. The data were analyzed with Statistical Package for the Social Sciences version 16.0. The results showed that the minimum and maximum concentrations of fluoride in the green tea infusions were 0.162 mg/L (cinnamon-flavored green tea and 3.29 mg/L (bagged peach-flavored green tea, respectively. The mean concentration of fluoride in the green tea leaves was 52 mg/kg, and approximately 89% of the fluoride was released from the green tea leaves into the infusions after brewing. The fluoride concentrations varied significantly among the examined green teas ( P 0.05. Finally, drinking of the studied green teas cannot make a significant contribution to the daily dietary intake of F for consumers.

Preparation and characterization of functional poly(vinylidene fluoride) (PVDF) membranes with ultraviolet-absorbing property

Science.gov (United States)

Dong, Li; Liu, Xiangdong; Xiong, Zhengrong; Sheng, Dekun; Lin, Changhong; Zhou, Yan; Yang, Yuming

2018-06-01

We first reported a strategy to prepare functional poly(vinylidene fluoride) (PVDF) membranes with excellent ultraviolet-absorbing property through chemically induced grafting. Herein, the polymerizable ultraviolet (UV) absorber 2-hydroxy-4-(3-methacryloxy-2-hydroxylpropoxy) benzophenone (BPMA) made by ourselves was grafted onto the PVDF chains that have been pretreated with tetraethylammonium hydroxide (TEAH) alkaline solution. Moreover, the effect of experiment conditions such as the alkali and monomer concentrations, alkali treatment time on the UV-absorbing property of the obtained PVDF-g-PBPMA membranes were studied in detail. The chemical structure of the modified membranes was confirmed by 1H NMR, FT-IR and XPS measurements. Meanwhile, the thermal and UV-absorbing properties were characterized by TGA, DSC and UV-Vis spectrophotometer, respectively. The results indicated that BPMA side chains were successfully introduced onto PVDF backbones. Most importantly, the obtained PVDF-g-PBPMA membranes exhibited excellent UV-absorbing property. The transmittance of UV light at 300 nm decreased to as low as 0.02% and the UV light below 388 nm could be completely absorbed by the PVDF-g-PBPMA membrane made under optimal condition.

Investigation of Fluoride Removal Efficiency from Aqueous Solution by Pistachio and Almonds Crust

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Maryam Khodadadi

2015-06-01

Full Text Available Introduction: Fluoride and its compounds are widely used in industries and then through effluent are released into the environment. The purpose of this study was to evaluate Efficiency of low cost adsorbents (pistachios coal in the removal of fluoride from aqueous solutions.  Methods: For the preparation of adsorbent, crust of pistachios deride, then washed with distilled water, then powder in the furnace for burning for 2 hours at temperatures of 500, 600, and 700 °C. The effect of changing pH, burning temperature of adsorbent, stirring speed, initial concentration of fluoride, retention time and adsorbent dose was studied. Concentration of fluoride measured according to standard method using spectrophotometer the data were analyzed using Excel software. Results: The results of these experiments showed that the burning adsorbent, temperature 500 ° C, PH of solution in the neutral range (pH = 7, adsorbent dose of 2 g/L for absorbing almonds and adsorbent dose of 3 g pistachio, contact time of 40 minutes for both adsorbent, initial fluoride concentration (5ppm for both absorbent without mixing, the optimal conditions for the efficiency of the absorber is as much as 90-80 percent. Discussion: According to the results, pistachio coal can be used with high efficiency for fluoride removal. 

Alimentary fluoride intake in preschool children

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Lencova Erika

2011-10-01

Full Text Available Abstract Background The knowledge of background alimentary fluoride intake in preschool children is of utmost importance for introducing optimal and safe caries preventive measures for both individuals and communities. The aim of this study was to assess the daily fluoride intake analyzing duplicate samples of food and beverages. An attempt was made to calculate the daily intake of fluoride from food and swallowed toothpaste. Methods Daily alimentary fluoride intake was measured in a group of 36 children with an average age of 4.75 years and an average weight of 20.69 kg at baseline, by means of a double plate method. This was repeated after six months. Parents recorded their child's diet over 24 hours and collected duplicated portions of food and beverages received by children during this period. Pooled samples of food and beverages were weighed and solid food samples were homogenized. Fluoride was quantitatively extracted from solid food samples by a microdiffusion method using hexadecyldisiloxane and perchloric acid. The content of fluoride extracted from solid food samples, as well as fluoride in beverages, was measured potentiometrically by means of a fluoride ion selective electrode. Results Average daily fluoride intake at baseline was 0.389 (SD 0.054 mg per day. Six months later it was 0.378 (SD 0.084 mg per day which represents 0.020 (SD 0.010 and 0.018 (SD 0.008 mg of fluoride respectively calculated per kg bw/day. When adding the values of unwanted fluoride intake from the toothpaste shown in the literature (0.17-1.21 mg per day the estimate of the total daily intake of fluoride amounted to 0.554-1.594 mg/day and recalculated to the child's body weight to 0.027-0.077 mg/kg bw/day. Conclusions In the children studied, observed daily fluoride intake reached the threshold for safe fluoride intake. When adding the potential fluoride intake from swallowed toothpaste, alimentary intake reached the optimum range for daily fluoride intake

Comparative evaluation of fluoride release from PRG-composites and compomer on application of topical fluoride: An in-vitro study

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Dhull K

2009-03-01

Full Text Available Aims and Objective: To determine the fluoride release from Giomer and Compomer, using different topical fluoride regimes, and to compare the amount of fluoride release from giomer with that of compomer. Materials and Method: Forty-eight specimens of each giomer and compomer were divided into four treatment groups, namely, control group, fluoridated dentifrice (500 ppm once daily group, fluoridated dentifrice (500 ppm twice daily group, fluoridated dentifrice (500 ppm once daily + fluoridated mouthwash (225 ppm group. Each specimen was suspended in demineralizing solution for six hours and remineralizing solution for 18 hours. Fluoride release was measured in both the demineralizing solution and remineralizing solution daily for seven days. Total daily fluoride release for each specimen was calculated by adding the amount released in the demineralizing solution to that released in remineralizing solution. Results and Conclusion: The fluoride release (ppm was found to be more in Giomer when compared to Compomer. The fluoride released from Giomer and Compomer was significantly greater in the acidic demineralizing solution than in the neutral remineralizing solution. It was found that increasing fluoride exposure significantly increased fluoride release from the giomer and compomer. It was found that the fluoride release from the subgroups of giomer and compomer was in the following order: fluoridated dentifrice twice daily > fluoridated dentifrice once daily + fluoridated mouthwash > fluoridated dentifrice once daily > control group. It was found that the giomer showed a greater fluoride uptake than the compomer.

Fluoride retention by kaolin clay

DEFF Research Database (Denmark)

Kau, P. M. H.; Smith, D. W.; Binning, Philip John

1997-01-01

To evaluate the potential effectiveness of kaolin clay liners in storage of fluoride contaminated waste, an experimental study of the sorption and desorption behaviour of fluoride in kaolin clay was conducted. The degree of fluoride sorption by kaolin was found to depend on solution p......H and available fluoride concentration with equilibrium being achieved within 24 h. A site activation process involving the uptake of fluoride was also observed at the initial stages of sorption. This behaviour was attributed to a layer expansion process of the clay during sorption. The maximum fluoride sorption...... capacity was found to be 18.3 meq/100 g at pH 6 and 8.6 meq/100 g at pH 7. A competitive Langmuir sorption isotherm where sorption is dependant on both pH and fluoride concentration is employed to characterise the experimental sorption and desorption data. The sorption and desorption isotherms revealed...

Process for producing a self luminescent material

Energy Technology Data Exchange (ETDEWEB)

Abe, E

1962-01-28

A self luminescent material is produced by a process comprising applying a hydroxide or fluoride of promethium-147 suspended in a medium of paraffinic acid to the surface of a fluorescent body. Promethium-147 decays with a half-life of 2.6 years and emits beta-rays but not alpha- and gamma-rays so that it is suitable for manufacturing self luminescent materials. A chloride of promethium-147 cannot be employed because its structure is destroyed by acids. Although fluorides and hydroxides of promethium-147 are difficult to mix with the fluorescent body material, they become mixable when paraffinic acids containing from 12 to 20 carbon atoms, (for example, steric acid, palmitic acid and margaric acid) are used as a medium. In embodiments, the self luminescent materials are prepared by either neutralization of a promethium-147 chloride solution having a specific radioactivity of 1.2 c/cc. with an ammonium hydroxide solution to form gelatinous hydroxide, or the reaction of a promethium-147 chloride solution with H/sub 2/SiF/sub 6/ by heating at 80/sup 0/C to form a fluoride of promethium-147. The products have a specific radioactivity of 8 to 12 mc/g. These products are suspended in vehicles of polystyrene and methacrylic resin to produce the self luminescent coating materials. Tests show that the initical brightness is comparatively high, the decreasing rate of brightness is small, no blackening effects by alpha-rays occur and costs are low. The brightness of the coating containing promethium-147 is 82-85 after 5 days, 100-105 after 100 days and 82-92 after 180 days. With respect to the coating containing radium the values are 31-70 after 5 days, 28-49 after 100 days and 19-31 after 180 days.

Fluoride analysis

Energy Technology Data Exchange (ETDEWEB)

Brandt, C S

1963-01-01

The methods and procedures for the detection and estimation of fluoride are varied and numerous. The problems of sampling, contamination, and loss in sampling waters, plant and animal tissues and atmospheres are discussed, along with brief descriptors of methods most commonly used. Techniques for separating fluorides from matrixes are discussed, as well as gravimetric, calorimetric, and spectrophotometric analytical techniques.

Comparison of fluoride uptake level by enamel from Iranian school brand and standard NaF mouthrinses

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Gasem Ansari

2009-03-01

Full Text Available Background and aims. The use of fluoride mouthrinses has been proved to be one of the most effective ways to prevent tooth decay. A community based program using F+ rinse at school has also proved to be well-controlled and efficient. The aim of this investigation was to evaluate fluoride uptake level of a locally prepared NaF rinse used in Iran’s school program during 2005. Materials and methods. A total of 30 freshly extracted sound human premolars were collected and divided into two groups of 15. Each tooth then underwent two steps of sectioning; first the root was amputated from CEJ and then a longitudinal section was performed in bucco-lingual direction to provide two similar samples of the same tooth. A specific hemi-circular area on either of the experimental halves was treated by NaF rinse from USA or a locally prepared NaF used in school programs. Two subsequent biopsies were taken from each half using acid etch enamel biopsy technique. Fluoride and calcium content of the specimens were measured in order to evaluate fluoride uptake level and biopsy depth effect, respectively. Collected data were recorded in the forms provided and statistical analysis, mostly descriptive, was performed for comparison. Results. Based on the data collected, it appears that the use of F+ rinse would clearly improve enamel quality by a rise in fluoride concentration. Statistical analysis using a paired t-test and repeated measure method revealed that with 95% confidence fluoride concentration increases at both levels of biopsy with no statistically significant differences between the samples treated with two rinses. Conclusion. There seem to be reasonable potential for the clinical use of Iranian brand fluoride mouthrinse. There was no significant difference between the level of uptake from NaF from USA and the Iranian product in 2 layers of enamel biopsy.

Story of Fluoridation

Science.gov (United States)

... Home Health Info Health Topics Fluoride Share The Story of Fluoridation It started as an observation, that ... this time using photospectrographic analysis, a more sophisticated technology than that used by McKay. Churchill asked an ...

Private Well Water and Fluoride

Science.gov (United States)

... Private Wells Infant Formula Fluorosis Public Health Service Recommendation Water Operators & Engineers Water Fluoridation Additives Shortages of Fluoridation Additives Drinking Water Pipe Systems CDC-Sponsored Water Fluoridation Training Links to Other ...

Matrix supported tailored polymer for solid phase extraction of fluoride from variety of aqueous streams

International Nuclear Information System (INIS)

Thakur, Neha; Kumar, Sanjukta A.; Wagh, D.N.; Das, Sadananda; Pandey, Ashok K.; Kumar, Sangita D.; Reddy, A.V.R.

2012-01-01

Highlights: ► Th complexed with poly (bis[2-(methacryloyloxy)-ethyl]phosphate) as tailored polymer membranes. ► Membranes offered high capacity and selectivity for fluoride in aqueous media. ► Quantitative uptake (80 ± 5%) of fluoride. ► Fast sorption kinetics. ► Reusability of polymer membranes. - Abstract: Fluoride related health hazards (fluorosis) are a major environmental problem in many regions of the world. It affects teeth; skeleton and its accumulation over a long period can lead to changes in the DNA structure. It is thus absolutely essential to bring down the fluoride levels to acceptable limits. Here, we present a new inorganic–organic hybrid polymer sorbent having tailored fixed-sites for fluoride sorption. The matrix supported poly (bis[2-(methacryloyloxy)-ethyl]phosphate) was prepared by photo-initiator induced graft-polymerization in fibrous and microporous (sheet) host poly(propylene) substrates. These substrates were conditioned for selective fluoride sorption by forming thorium complex with phosphate groups on bis[2-methacryloyloxy)-ethyl] phosphate (MEP). These tailored sorbents were studied for their selectivity towards fluoride in aqueous media having different chemical conditions. The fibrous sorbent was found to take up fluoride with a faster rate (15 min for ≈76% sorption) than the sheet sorbent. But, the fluoride loading capacity of sheet sorbent (4320 mg kg −1 ), was higher than fibrous and any other sorbent reported in the literature so far. The sorbent developed in the present work was found to be reusable after desorption of fluoride using NaOH solution. It was tested for solid phase extraction of fluoride from natural water samples.

Fluoride in diet

Science.gov (United States)

Diet - fluoride ... bones and teeth. Too much fluoride in the diet is very rare. Rarely, infants who get too ... of essential vitamins is to eat a balanced diet that contains a variety of foods from the ...

Hydrothermal synthesis and formation mechanism of hexagonal yttrium hydroxide fluoride nanobundles

International Nuclear Information System (INIS)

Tian, Li; Sun, QiLiang; Zhao, RuiNi; He, HuiLin; Xue, JianRong; Lin, Jun

2013-01-01

Graphical abstract: The formation of yttrium hydroxide fluorides nanobundles can be expressed as a precipitation transformation from cubic NaYF 4 to hexagonal NaYF 4 and to hexagonal Y(OH) 2.02 F 0.98 owing to ion exchange. - Highlights: • Novel Y(OH) 2.02 F 0.98 nanobundles have been successfully prepared by hydrothermal method. • The branched nanobundles composed of numerous oriented-attached nanoparticles has been studied. • The growth mechanism is proposed to be ion exchange and precipitation transformation. - Abstract: This article presents the fabrication of hexagonal yttrium hydroxide fluoride nanobundles via one-pot hydrothermal process, using yttrium nitrate, sodium hydroxide and ammonia fluoride as raw materials to react in propanetriol solvent. The X-ray diffraction pattern clearly reveals that the grown product is pure yttrium hydroxide fluoride, namely Y(OH) 2.02 F 0.98 . The morphology and microstructure of the synthesized product is testified to be nanobundles composed of numerous oriented-attached nanoparticles as observed from the field emission scanning electron microscopy (FESEM). The chemical composition was analyzed by the energy dispersive spectrum (EDS), confirming the phase transformation of the products which was clearly consistent with the result of XRD analysis. It is proposed that the growth of yttrium hydroxide fluoride nanobundles be attributed to ion exchange and precipitation transformation

Blood clearance rates of technetium-99m albumin preparations: concise communication

International Nuclear Information System (INIS)

Nusynowitz, M.L.; Straw, J.D.; Benedetto, A.R.; Dixon, R.S.

1978-01-01

Technetium-labeled human serum albumin (HSA) is extensively used as a cardiac imaging agent. An evaluation of the blood-clearance rates of electrolytically reduced HSA (EHSA) and four stannous-reduced HSA (SnHSA) preparations was conducted in dogs, and was compared with that of radioiodinated HSA (IHSA). The EHSA was found to have a clearance rate only about 1.5 times that of IHSA, whereas the SnHSA agents were cleared at two to five times the rate of IHSA. Thus, EHSA has definite advantages over SnHSA preparations for the purposes of blood-volume determinations required in quantitative cardiac studies and for the reduction of extravascular background in the accurate delineation of cardiac boundaries

Technetium-99m stannous pyrophosphate imaging of experimental infective endocarditis

International Nuclear Information System (INIS)

Riba, A.L.; Downs, J.; Thakur, M.L.; Gottschalk, A.; Andriole, V.T.; Zaret, B.L.

1978-01-01

Technetium-99m stannous pyrophosphate (/sup 99m/Tc-PYP) cardiac scintigraphy was performed in 15 rabbits with experimental Streptococcus sanguis aortic-valve infective endocarditis. The animals were imaged five to seven days after the administration of bacteria, and in each case abnormal accumulation of the tracer was visualized in the region of the aortic valve. Three types of cardiac scintigraphic patterns were demonstrated: focal, multifocal, and extensive, each correlating well with the anatomical extent of the lesion as defined by gross pathology. Tissue distribution studies demonstrated a 30 +- 5.3 (mean +- SEM) fold excess of radionuclide uptake in the infective endocarditis lesion compared with that of normal myocardium. Imaging of excised hearts from four animals showed an excellent correlation with in vivo imaging as well as gross pathology. Five animals with nonbacterial thrombotic aortic valve endocarditis demonstrated similar scintigraphic and tissue distribution results. In contrast, four normal animals failed to demonstrate abnormal /sup 99m/Tc-PYP cardiac scintigrams or tissue uptake. This study demonstrates that /sup 99m/Tc-PYP cardiac scintigraphy is a sensitive technique to detect experimental aortic valve endocarditis

Dietary Fluoride Intake and Associated Skeletal and Dental Fluorosis in School Age Children in Rural Ethiopian Rift Valley

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Aweke Kebede

2016-07-01

Full Text Available An observational study was conducted to determine dietary fluoride intake, diet, and prevalence of dental and skeletal fluorosis of school age children in three fluorosis endemic districts of the Ethiopian Rift Valley having similar concentrations of fluoride (F in drinking water (~5 mg F/L. The duplicate plate method was used to collect foods consumed by children over 24 h from 20 households in each community (n = 60 and the foods, along with water and beverages, were analyzed for fluoride (F content. Prevalence of dental and skeletal fluorosis was determined using presence of clinical symptoms in children (n = 220. Daily dietary fluoride intake was at or above tolerable upper intake level (UL of 10 mg F/day and the dietary sources (water, prepared food and beverages all contributed to the daily fluoride burden. Urinary fluoride in children from Fentale and Adamitulu was almost twice (>5 mg/L the concentration found in urine from children from Alaba, where rain water harvesting was most common. Severe and moderate dental fluorosis was found in Alaba and Adamitulu, the highest severity and prevalence being in the latter district where staple foods were lowest in calcium. Children in all three areas showed evidence of both skeletal and non-skeletal fluorosis. Our data support the hypothesis that intake of calcium rich foods in addition to using rain water for household consumption and preparation of food, may help in reducing risk of fluorosis in Ethiopia, but prospective studies are needed.

The effect of pretreatment with fluoride on the tensile strength of orthodontic bonding

International Nuclear Information System (INIS)

Wang, W.N.; Sheen, D.H.

1991-01-01

White spot decalcifications and caries occurring adjacent to bonded orthodontic brackets have long been a concern to orthodontists. One procedure suggested to overcome this problem is fluoride treatment prior to bonding. The purpose of this study was to compare the tensile bond strength of orthodontic self-cured resin from Concise on teeth rinsed 4 minutes in 1.23% APF with untreated controls. Measurements were made on an Instron machine. Debonding interfaces were observed with a scanning electron microscope and energy dispersive x-ray spectrometry. Distributions were calculated. The tensile bond strengths of the fluoride-treated teeth and the untreated teeth were not significantly different. The debonding interfaces between resin and bracket base, within the resin itself, and between enamel and resin were similar in the two experimental groups. However, greater enamel detachment was seen within the fluoride pretreatment group. So while fluoride pretreatment does not significantly affect tensile bond strength, it may cause enamel detachment after debonding

Preparation of self-supporting thin metal target films

International Nuclear Information System (INIS)

Wang Xiuying; Ge Suxian; Yin Jianhua; Yin Xu; Jin Genming

1989-01-01

The preparation method and equipment for thin metal self-supporting target without oil contamination are described. The influence of target films contaminated by oil vapor on accuracy of nuclear-physics experimental data are also discussed. The analytical results on carbon content in the prepared films of three elements show that the equipment is very effective for eliminating contamination

Effect of fluoride varnishes on color stability of esthetic restorative materials.

Science.gov (United States)

Autio-Gold, Jaana T; Barrett, Allyson A

2004-01-01

Fluoride varnish applications were applied to two hybrid resin composite materials, Z-100 (3M Dental Products, St Paul, MN, USA) and Esthet-X (Dentsply Caulk, Milford, DE, USA), shades A1 and A2 and a glass ionomer, GC Fuji IX GP Fast (GC Corporation, Tokyo, Japan), shade A2, to evaluate color stability. Specimens (12.6-mm dia x 2.3 mm) were prepared using a polyethylene frame, light-cured and polished through a 1-microm alumina finish. After the initial baseline color measurements, the discs were suspended in Fusayama artificial saliva (FAS) solution at 37 degrees C for 48 hours. Post immersion, the specimens were divided into five groups (n=15 each). The following fluoride varnishes were applied to four groups of test specimens: Duraphat (Colgate Oral Pharmaceutical, Inc, Canton MA, USA), Cavity Shield (OMNII Oral Pharmaceuticals, West Palm Beach, FL, USA), Duraflor (Pharmascience Inc, Montreal, Canada) and Fluor Protector (Vivadent, Ivoclar North America, Amherst, NY, USA). The varnish was allowed to dry for five minutes before immersion. The control group was not coated with varnish, although the specimens were immersed in FAS. All specimens were incubated in newly prepared FAS at 37 degrees C for 24 hours, cleaned with an electric toothbrush and the process repeated using newly prepared FAS. CIE L*a*b* color measurements were recorded five times: at baseline, after 48 hours FAS immersion, after cleaning the first and second fluoride varnish applications and after the final brushing using a commercial toothpaste (Crest). A Minolta CR-300 tristimulus colorimeter with an 8-mm aperture (Ramsey, NJ, USA) was used to record color measurements with the daylight (D65) setting. Calculations were performed for using CIE parameters deltaE*, deltaL*, delta a*, delta b*. Analysis of variance (ANOVA) and post-hoc test (Fisher's PLSD) were used for statistical analysis. After immersion in saliva, the tested glass ionomer (Fuji IX) produced the most significant color changes

Fluoride removal from double four-membered ring (D4R) units in As-synthesized Ge-containing zeolites

KAUST Repository

Liu, Xiaolong

2011-11-22

Fluoride anions can be removed from the framework of as-prepared Ge-containing zeolites ITQ-13 and ITQ-17 without modification of the crystallinity and crystal habit. By contrast to all-silica ITQ-13 for which fluoride could not get out from D4R units, F is completely removed from Ge rich zeolites, even from D4R cages. This has been explained by the relaxing effect of germanium, making F less necessary for the stabilization of the small D4R units. Si/Ge ratios are similar in as-prepared and treated zeolites, indicating that the framework composition is not affected by the removal of anions. The fluoride-free zeolites possess XRD patterns similar to those of the as-made solids but their 29Si NMR spectra are significantly different, revealing the sensitivity of the method to the environment of silicon atoms in the framework. The extent of fluoride that can be removed from D4R units depends not only on the framework Ge content but also on the zeolite topology: for similar contents, F is much more easily eliminated from ITQ-17 than from ITQ-13. © 2011 American Chemical Society.

Preparation of Atomically Flat Si(111)-H Surfaces in Aqueous Ammonium Fluoride Solutions Investigated by Using Electrochemical, In Situ EC-STM and ATR-FTIR Spectroscopic Methods

International Nuclear Information System (INIS)

Bae, Sang Eun; Oh, Mi Kyung; Min, Nam Ki; Paek, Se Hwan; Hong, Suk In; Lee, Chi-Woo J.

2004-01-01

Electrochemical, in situ electrochemical scanning tunneling microscope (EC-STM), and attenuated total reflectance-FTIR (ATR-FTIR) spectroscopic methods were employed to investigate the preparation of atomically flat Si(111)-H surface in ammonium fluoride solutions. Electrochemical properties of atomically flat Si(111)-H surface were characterized by anodic oxidation and cathodic hydrogen evolution with the open circuit potential (OCP) of ca. .0.4 V in concentrated ammonium fluoride solutions. As soon as the natural oxide-covered Si(111) electrode was immersed in fluoride solutions, OCP quickly shifted to near .1 V, which was more negative than the flat band potential of silicon surface, indicating that the surface silicon oxide had to be dissolved into the solution. OCP changed to become less negative as the oxide layer was being removed from the silicon surface. In situ EC-STM data showed that the surface was changed from the initial oxide covered silicon to atomically rough hydrogen-terminated surface and then to atomically flat hydrogen terminated surface as the OCP moved toward less negative potentials. The atomically flat Si(111)-H structure was confirmed by in situ EC-STM and ATR-FTIR data. The dependence of atomically flat Si(111)-H terrace on mis-cut angle was investigated by STM, and the results agreed with those anticipated by calculation. Further, the stability of Si(111)-H was checked by STM in ambient laboratory conditions

Development of [18F]halofluorination and [18F]fluoride ion displacement reactions for the synthesis of F-18 labelled radiopharmaceuticals

International Nuclear Information System (INIS)

Chi, D.Y.

1986-01-01

Two fluorine-18 labeling methods, [ 18 F]halofluorination and [ 18 F]fluoride ion displacement reactions, have been developed to assess their potential for labeling molecules with the positron-emitting radionuclide fluorine-18 at the no-carrier-added level. Olefin halofluorination involves the in situ generation of a halogen-fluoride reagent and subsequent addition to an olefin. The characteristics of this reaction were investigated with three model olefins (allylbenzene, 1-hexene, and propene). A two-step method for the preparation of fluoroalkyl substituted amines and amides has been achieved. The sequence involves fluoride ion displacement of trifluoromethanesulfonates (triflates) from short-chain haloalkyl triflates, followed by fluoroalkylation of the amine or amide. Alternatively, short-chain fluoroalkyl halides can be prepared by halofluorination of a terminal olefin. These reactions have been used to prepare various fluoroalkyl derivatives of 1-phenylpiperazine and N-fluoroalkyl derivatives of the neuroleptic agent spiperone. A series of fluorine-18 labeled N-fluoroalkylated spiperone derivatives were synthesized by N-alkylation of spiperone with fluoroalkyl halides

Physiology and toxicity of fluoride

Directory of Open Access Journals (Sweden)

Dhar Vineet

2009-01-01

Full Text Available Fluoride has been described as an essential element needed for normal development and growth of animals and extremely useful for human beings. Fluoride is abundant in the environment and the main source of fluoride to humans is drinking water. It has been proved to be beneficial in recommended doses, and at the same time its toxicity at higher levels has also been well established. Fluoride gets accumulated in hard tissues of the body and has been know to play an important role in mineralization of bone and teeth. At high levels it has been known to cause dental and skeletal fluorosis. There are suggested effects of very high levels of fluoride on various body organs and genetic material. The purpose of this paper is to review the various aspects of fluoride and its importance in human life.

Physiology and toxicity of fluoride.

Science.gov (United States)

Dhar, Vineet; Bhatnagar, Maheep

2009-01-01

Fluoride has been described as an essential element needed for normal development and growth of animals and extremely useful for human beings. Fluoride is abundant in the environment and the main source of fluoride to humans is drinking water. It has been proved to be beneficial in recommended doses, and at the same time its toxicity at higher levels has also been well established. Fluoride gets accumulated in hard tissues of the body and has been know to play an important role in mineralization of bone and teeth. At high levels it has been known to cause dental and skeletal fluorosis. There are suggested effects of very high levels of fluoride on various body organs and genetic material. The purpose of this paper is to review the various aspects of fluoride and its importance in human life.

Fluoride barriers in Nb/Pb Josephson junctions

Science.gov (United States)

Asano, H.; Tanabe, K.; Michikami, O.; Igarashi, M.; Beasley, M. R.

1985-03-01

Josephson tunnel junctions are fabricated using a new class of artificial barriers, metal fluorides (Al fluoride and Zr fluoride). These fluoride barriers are deposited on the surface of a Nb base electrode, which are previously cleaned using a CF4 cleaning process, and covered by a Pb counterelectrode. The junctions with both Al fluoride and Zr fluoride barriers exhibit good tunneling characteristics and have low specific capacitance. In the case of Zr fluoride, it is observed that reasonable resistances are obtained even at thickness greater than 100 A. This phenomenon might be explained by tunneling via localized states in Zr fluoride.

Fluoride exposure and indicators of thyroid functioning in the Canadian population: implications for community water fluoridation.

Science.gov (United States)

Barberio, Amanda M; Hosein, F Shaun; Quiñonez, Carlos; McLaren, Lindsay

2017-10-01

There are concerns that altered thyroid functioning could be the result of ingesting too much fluoride. Community water fluoridation (CWF) is an important source of fluoride exposure. Our objectives were to examine the association between fluoride exposure and (1) diagnosis of a thyroid condition and (2) indicators of thyroid functioning among a national population-based sample of Canadians. We analysed data from Cycles 2 and 3 of the Canadian Health Measures Survey (CHMS). Logistic regression was used to assess associations between fluoride from urine and tap water samples and the diagnosis of a thyroid condition. Multinomial logistic regression was used to examine the relationship between fluoride exposure and thyroid-stimulating hormone (TSH) level (low/normal/high). Other available variables permitted additional exploratory analyses among the subset of participants for whom we could discern some fluoride exposure from drinking water and/or dental products. There was no evidence of a relationship between fluoride exposure (from urine and tap water) and the diagnosis of a thyroid condition. There was no statistically significant association between fluoride exposure and abnormal (low or high) TSH levels relative to normal TSH levels. Rerunning the models with the sample constrained to the subset of participants for whom we could discern some source(s) of fluoride exposure from drinking water and/or dental products revealed no significant associations. These analyses suggest that, at the population level, fluoride exposure is not associated with impaired thyroid functioning in a time and place where multiple sources of fluoride exposure, including CWF, exist. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Water Fluoridation: A Critical Review of the Physiological Effects of Ingested Fluoride as a Public Health Intervention

Science.gov (United States)

2014-01-01

Fluorine is the world's 13th most abundant element and constitutes 0.08% of the Earth crust. It has the highest electronegativity of all elements. Fluoride is widely distributed in the environment, occurring in the air, soils, rocks, and water. Although fluoride is used industrially in a fluorine compound, the manufacture of ceramics, pesticides, aerosol propellants, refrigerants, glassware, and Teflon cookware, it is a generally unwanted byproduct of aluminium, fertilizer, and iron ore manufacture. The medicinal use of fluorides for the prevention of dental caries began in January 1945 when community water supplies in Grand Rapids, United States, were fluoridated to a level of 1 ppm as a dental caries prevention measure. However, water fluoridation remains a controversial public health measure. This paper reviews the human health effects of fluoride. The authors conclude that available evidence suggests that fluoride has a potential to cause major adverse human health problems, while having only a modest dental caries prevention effect. As part of efforts to reduce hazardous fluoride ingestion, the practice of artificial water fluoridation should be reconsidered globally, while industrial safety measures need to be tightened in order to reduce unethical discharge of fluoride compounds into the environment. Public health approaches for global dental caries reduction that do not involve systemic ingestion of fluoride are urgently needed. PMID:24719570

Review on fluoride-releasing restorative materials--fluoride release and uptake characteristics, antibacterial activity and influence on caries formation.

Science.gov (United States)

Wiegand, Annette; Buchalla, Wolfgang; Attin, Thomas

2007-03-01

The purpose of this article was to review the fluoride release and recharge capabilities, and antibacterial properties, of fluoride-releasing dental restoratives, and discuss the current status concerning the prevention or inhibition of caries development and progression. Information from original scientific full papers or reviews listed in PubMed (search term: fluoride release AND (restorative OR glass-ionomer OR compomer OR polyacid-modified composite resin OR composite OR amalgam)), published from 1980 to 2004, was included in the review. Papers dealing with endodontic or orthodontic topics were not taken into consideration. Clinical studies concerning secondary caries development were only included when performed in split-mouth design with an observation period of at least three years. Fluoride-containing dental materials show clear differences in the fluoride release and uptake characteristics. Short- and long-term fluoride releases from restoratives are related to their matrices, setting mechanisms and fluoride content and depend on several environmental conditions. Fluoride-releasing materials may act as a fluoride reservoir and may increase the fluoride level in saliva, plaque and dental hard tissues. However, clinical studies exhibited conflicting data as to whether or not these materials significantly prevent or inhibit secondary caries and affect the growth of caries-associated bacteria compared to non-fluoridated restoratives. Fluoride release and uptake characteristics depend on the matrices, fillers and fluoride content as well as on the setting mechanisms and environmental conditions of the restoratives. Fluoride-releasing materials, predominantly glass-ionomers and compomers, did show cariostatic properties and may affect bacterial metabolism under simulated cariogenic conditions in vitro. However, it is not proven by prospective clinical studies whether the incidence of secondary caries can be significantly reduced by the fluoride release of

Silver diamine fluoride: a caries "silver-fluoride bullet".

Science.gov (United States)

Rosenblatt, A; Stamford, T C M; Niederman, R

2009-02-01

The antimicrobial use of silver compounds pivots on the 100-year-old application of silver nitrate, silver foil, and silver sutures for the prevention and treatment of ocular, surgical, and dental infections. Ag(+) kills pathogenic organisms at concentrations of linings, water purification systems, hospital gowns, and caries prevention. To distill the current best evidence relative to caries, this systematic review asked: Will silver diamine fluoride (SDF) more effectively prevent caries than fluoride varnish? A five-database search, reference review, and hand search identified 99 human clinical trials in three languages published between 1966 and 2006. Dual review for controlled clinical trials with the patient as the unit of observation, and excluding cross-sectional, animal, in vitro studies, and opinions, identified 2 studies meeting the inclusion criteria. The trials indicated that SDF's lowest prevented fractions for caries arrest and caries prevention were 96.1% and 70.3%, respectively. In contrast, fluoride varnish's highest prevented fractions for caries arrest and caries prevention were 21.3% and 55.7%, respectively. Similarly, SDF's highest numbers needed to treat for caries arrest and caries prevention were 0.8 (95% CI=0.5-1.0) and 0.9 (95% CI=0.4-1.1), respectively. For fluoride varnish, the lowest numbers needed to treat for caries arrest and prevention were 3.7 (95% CI=3.4-3.9) and 1.1 (95% CI=0.7-1.4), respectively. Adverse events were monitored, with no significant differences between control and experimental groups. These promising results suggest that SDF is more effective than fluoride varnish, and may be a valuable caries-preventive intervention. As well, the availability of a safe, effective, efficient, and equitable caries-preventive agent appears to meet the criteria of both the WHO Millennium Goals and the US Institute of Medicine's criteria for 21st century medical care.

Preparation of99mTc - dextran-500 for use in lymphoscintigraphy

International Nuclear Information System (INIS)

Hamada, E.S.; Muramoto, E.; Pereira, N.P.S. de; Brito, R.H.; Silva, C.P.G. da.

1990-03-01

This paper reported the preparation of lyophilized kit Dextran-500 for labelling with 99m Tc used in Nuclear Medicine as a lymphoscintigraphic agent. Each vial contains 100 mg Dextran-500 and 1,5 mg stannous chloride. The radiopharmaceutical was checked by ITLC, and the radiochemical purity and stability were determined. The studies of biological distribution were made in Wistar rats and the clinical evaluation in men was realized. Our results permited to incorporate Dextran-500 formulation as an ideal agent for routine use in lymphoscintigraphic. (author) [pt

49 CFR 173.163 - Hydrogen fluoride.

Science.gov (United States)

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Hydrogen fluoride. 173.163 Section 173.163... Hydrogen fluoride. (a) Hydrogen fluoride (hydrofluoric acid, anhydrous) must be packaged as follows: (1) In... filling ratio of 0.84. (b) A cylinder removed from hydrogen fluoride service must be condemned in...

FLUORIDE TOXICITY – A HARSH REALITY

OpenAIRE

Bandlapalli Pavani; Mandava Ragini; David Banji; Otilia J F Banji; N Gouri Pratusha

2011-01-01

There are many incidents of fluoride toxicity whether it is acute or chronic. Fluoride toxicity is an environmental hazard which arises from the upper layers of geological crust and is dissolved in water. Prolonged drinking of such water causes chronic fluoride toxicity. Use of fluoride containing compounds for various purposes such as dental products, metal, glass, refrigerator and chemical industries act as a source of fluoride poisoning and increase the risk of toxicity. This review reflec...

Fluoride in groundwater: toxicological exposure and remedies.

Science.gov (United States)

Jha, S K; Singh, R K; Damodaran, T; Mishra, V K; Sharma, D K; Rai, Deepak

2013-01-01

Fluoride is a chemical element that is found most frequently in groundwater and has become one of the most important toxicological environmental hazards globally. The occurrence of fluoride in groundwater is due to weathering and leaching of fluoride-bearing minerals from rocks and sediments. Fluoride when ingested in small quantities (dental health by reducing dental caries, whereas higher concentrations (>1.5 mg/L) may cause fluorosis. It is estimated that about 200 million people, from among 25 nations the world over, may suffer from fluorosis and the causes have been ascribed to fluoride contamination in groundwater including India. High fluoride occurrence in groundwaters is expected from sodium bicarbonate-type water, which is calcium deficient. The alkalinity of water also helps in mobilizing fluoride from fluorite (CaF2). Fluoride exposure in humans is related to (1) fluoride concentration in drinking water, (2) duration of consumption, and (3) climate of the area. In hotter climates where water consumption is greater, exposure doses of fluoride need to be modified based on mean fluoride intake. Various cost-effective and simple procedures for water defluoridation techniques are already known, but the benefits of such techniques have not reached the rural affected population due to limitations. Therefore, there is a need to develop workable strategies to provide fluoride-safe drinking water to rural communities. The study investigated the geochemistry and occurrence of fluoride and its contamination in groundwater, human exposure, various adverse health effects, and possible remedial measures from fluoride toxicity effects.

TiO 2 Thin Films Prepared via Adsorptive Self-Assembly for Self-Cleaning Applications

KAUST Repository

Xi, Baojuan

2012-02-22

Low-cost controllable solution-based processes for preparation of titanium oxide (TiO 2) thin films are highly desirable, because of many important applications of this oxide in catalytic decomposition of volatile organic compounds, advanced oxidation processes for wastewater and bactericidal treatments, self-cleaning window glass for green intelligent buildings, dye-sensitized solar cells, solid-state semiconductor metal-oxide solar cells, self-cleaning glass for photovoltaic devices, and general heterogeneous photocatalysis for fine chemicals etc. In this work, we develop a solution-based adsorptive self-assembly approach to fabricate anatase TiO 2 thin films on different glass substrates such as simple plane glass and patterned glass at variable compositions (normal soda lime glass or solar-grade borofloat glass). By tuning the number of process cycles (i.e., adsorption-then-heating) of TiO 2 colloidal suspension, we could facilely prepare large-area TiO 2 films at a desired thickness and with uniform crystallite morphology. Moreover, our as-prepared nanostructured TiO 2 thin films on glass substrates do not cause deterioration in optical transmission of glass; instead, they improve optical performance of commercial solar cells over a wide range of incident angles of light. Our as-prepared anatase TiO 2 thin films also display superhydrophilicity and excellent photocatalytic activity for self-cleaning application. For example, our investigation of photocatalytic degradation of methyl orange indicates that these thin films are indeed highly effective, in comparison to other commercial TiO 2 thin films under identical testing conditions. © 2012 American Chemical Society.

Purification process of uranium hexafluoride containing traces of plutonium fluoride and/or neptunium fluoride

International Nuclear Information System (INIS)

Aubert, J.; Bethuel, L.; Carles, M.

1983-01-01

In this process impure uranium hexafluoride is contacted with a metallic fluoride chosen in the group containing lead fluoride PbF 2 , uranium fluorides UFsub(4+x) (0 3 at a temperature such as plutonium and/or neptunium are reduced and pure uranium hexafluoride is recovered. Application is made to uranium hexafluoride purification in spent fuel reprocessing [fr

Fluoride removal performance of glass derived hydroxyapatite

International Nuclear Information System (INIS)

Liang, Wen; Zhan, Lei; Piao, Longhua; Russel, Christian

2011-01-01

Research highlights: → Novel sodium calcium borate glass derived hydroxyapatite (G-HAP) is prepared. → Micro-G-HAP adsorbs F - ions in solutions more effectively than commercial nano-HAP. → The adsorption kinetics and isotherms are well fitted by a second order kinetic model and Freundlich isotherm model. -- Abstract: A novel sodium calcium borate glass derived hydroxyapatite (G-HAP) with different ranges of particle size was prepared by immersion sodium calcium borate glass in 0.1 M K 2 HPO 4 solution by the ratio of 50 g L -1 for 7 days. The unique advantage of G-HAP for the adsorption of fluoride ions in solutions was studied. The effects of size and quantity of particles, pH value and adsorption time on adsorption performance were investigated. The maximum adsorption capacity was 17.34 mg g -1 if 5 g L -1 , - in solution more effectively than commercial nano-HAP, which makes potential application of the G-HAP in removing the fluoride ions from wastewater. The adsorption kinetics and isotherms for F - could be well fitted by a second order kinetic model and Freundlich isotherm model respectively, which could be used to describe the adsorption behavior. The mechanism of G-HAP in immobilizing F - from aqueous solutions was investigated by the X-ray diffraction (XRD), infrared spectra (IR) and scanning electron microscopy (SEM).

Tribological properties of PM212: A high-temperature, self-lubricating, powder metallurgy composite

Science.gov (United States)

Dellacorte, Christopher; Sliney, Harold E.

1989-01-01

This paper describes a research program to develop and evaluate a new high temperature, self-lubricating powder metallurgy composite, PM212. PM212 has the same composition as the plasma-sprayed coating, PS212, which contains 70 wt percent metal-bonded chromium carbide, 15 wt percent silver and 15 wt percent barium fluoride/calcium fluoride eutectic. The carbide acts as a wear resistant matrix and the silver and fluorides act as low and high temperature lubricants, respectively. The material is prepared by sequential cold press, cold isostatic pressing and sintering techniques. In this study, hemispherically tipped wear pins of PM212 were prepared and slid against superalloy disks at temperatures from 25 to 850 C in air in a pin-on-disk tribometer. Friction coefficients range from 0.29 to 0.38 and the wear of both the composite pins and superalloy disks was moderate to low in the 10(exp -5) to 10(exp -6) cubic mm/N-m range. Preliminary tests indicate that the material has a compressive strength of at least 130 MPa over the entire temperature range of 25 to 900 C. This material has promise for use as seal inserts, bushings, small inside diameter parts and other applications where plasma-sprayed coatings are impractical or too costly.

Tribological properties of PM212 - A high temperature, self-lubricating, powder metallurgy composite

Science.gov (United States)

Dellacorte, Christopher; Sliney, Harold E.

1990-01-01

This paper describes a research program to develop and evaluate a new high temperature, self-lubricating powder metallurgy composite, PM212. PM212 has the same composition as the plasma-sprayed coating, PS212, which contains 70 wt percent metal-bonded chromium carbide, 15 wt percent silver and 15 wt percent barium fluoride/calcium fluoride eutectic. The carbide acts as a wear resistant matrix and the silver and fluorides act as low and high temperature lubricants, respectively. The material is prepared by sequential cold press, cold isostatic pressing and sintering techniques. In this study, hemispherically tipped wear pins of PM212 were prepared and slid against superalloy disks at temperatures from 25 to 850 C in air in a pin-on-disk tribometer. Friction coefficients range from 0.29 to 0.38 and the wear of both the composite pins and superalloy disks was moderate to low in the 10(exp -5) to 10(exp -6) cubic mm/N-m range. Preliminary tests indicate that the material has a compressive strength of at least 130 MPa over the entire temperature range of 25 to 900 C. This material has promise for use as seal inserts, bushings, small inside diameter parts and other applications where plasma-sprayed coatings are impractical or too costly.

Physiology and toxicity of fluoride

OpenAIRE

Dhar Vineet; Bhatnagar Maheep

2009-01-01

Fluoride has been described as an essential element needed for normal development and growth of animals and extremely useful for human beings. Fluoride is abundant in the environment and the main source of fluoride to humans is drinking water. It has been proved to be beneficial in recommended doses, and at the same time its toxicity at higher levels has also been well established. Fluoride gets accumulated in hard tissues of the body and has been know to play an important role in mineralizat...

Study on the preparation and stability of 188Re biomolecules via EHDP

International Nuclear Information System (INIS)

Ferro-Flores, G.; Garcia-Salinas, L.; Paredes-Gutierrez, L.; Hashimoto, K.; Melendez-Alafort, L.; Murphy, C.A.

2001-01-01

A direct labelling technique via ethane-1-hydroxy-1,1-diphosphonic acid (EHDP) as a weak competing ligand was developed for the preparation of several biomolecules: 188 Re-monoclonal antibody ior cea1 against carcinoembryonic antigen ( 188 Re-MoAb), biotinylated 188 Re-MoAb ( 188 Re-MoAb-biotin), 188 Re-polyclonal IgG ( 188 Re-IgG), 188 Re-peptide (somatostatine analogue peptide b-(2-naphtyl)-D-Ala-Cys-Tyr-D-Trp-Lys-Val-Cys-Thr-amide), 188 Re-MoAb fragments ( 188 Re-F(ab') 2 ) and biotinylated 188 Re-F(ab') 2 ( 188 Re-F(ab') 2 -biotin). The reaction conditions such as pH, temperature, weak ligand concentration and stannous chloride concentration were optimized during the radiolabelling of each biomolecule. Before the labelling procedure, disulphide bridge groups of the biomolecules were reduced with 2-mercaptoethanol (2-ME). To obtain 188 Re labelled antibodies and peptides in high radiochemical yields (>90%) via EHDP, it was necessary to use acidic conditions and a high concentration of stannous chloride to allow the redox reaction Re +7 →Re +5 :Re +4 . The labelling of MoAb and F(ab') 2 with 188 Re via EHDP was also evaluated employing a pretargeted technique by avidin-biotin strategy in normal mice, demonstrating that the 188 Re-labelled biotinylated antibodies are stable complexes in vivo. The 188 Re-peptide complex prepared by this method, was stable for 24 h and no radiolytic degradation was observed. (author)

The Effect of Calcium Pre-Rinse on Salivary Fluoride After 900 ppm Fluoride Mouthwash: A Randomized Clinical Trial

Directory of Open Access Journals (Sweden)

Nahid Ramazani

2013-01-01

Full Text Available Objective: Calcium fluoride deposit during fluoride application. Uptake and retention of fluoride by saliva depends generally on the concentration of calcium. In this study, the ef-fect of calcium pre-rinse on salivary fluoride concentration after a 900 ppm fluoride mouthwash was investigated.Materials and Methods: This cross-over double-blind randomized clinical trial was con-ducted in a girls' dormitory in Zahedan University of Medical Sciences, southeast Iran. In this study, 42 female dental students were chosen using simple randomization. During the first phase, 21 subjects (group A used fluoride rinse (F regimen and the remaining (group B used calcium pre-rinse followed immediately by fluoride rinse (Ca + F regi-men. In the second phase, participants rinsed using the mouthwashes not previously used. Prior to each phase prophylaxis was performed and no fluoridated product was used dur-ing a two-week interval between the phases. Salivary samples were taken immediately be-fore (baseline, 1 and 12 hours after rinsing. The salivary fluoride concentration was de-termined using fluoride sensitive electrode. Repeated measures ANOVA was used for sta-tistical analysis and the significance level was set at P<0.05.Results: There was significant difference between fluoride concentrations at different time points (P< 0.001. Significant differences were observed when the different time points of two regimens were examined. In contrast to this, the baseline before using F regimen and the baseline before using Ca + F regimen did not show any significance (P= 0.070.Conclusion: Pre-rinsing with calcium before fluoride is recommended because of signifi-cant increases in salivary fluoride concentration.

Fluoride resistance in Streptococcus mutans

NARCIS (Netherlands)

Liao, Ying

2017-01-01

Fluoride has been used as the most effective anti-caries agent for over five decades. It functions not only on the dental hard tissues, but also as an antimicrobial agent. It is known that oral bacteria are able to develop resistance to fluoride, which may affect the effectiveness of fluoride in

Molecular mechanisms of fluoride toxicity.

Science.gov (United States)

Barbier, Olivier; Arreola-Mendoza, Laura; Del Razo, Luz María

2010-11-05

Halfway through the twentieth century, fluoride piqued the interest of toxicologists due to its deleterious effects at high concentrations in human populations suffering from fluorosis and in in vivo experimental models. Until the 1990s, the toxicity of fluoride was largely ignored due to its "good reputation" for preventing caries via topical application and in dental toothpastes. However, in the last decade, interest in its undesirable effects has resurfaced due to the awareness that this element interacts with cellular systems even at low doses. In recent years, several investigations demonstrated that fluoride can induce oxidative stress and modulate intracellular redox homeostasis, lipid peroxidation and protein carbonyl content, as well as alter gene expression and cause apoptosis. Genes modulated by fluoride include those related to the stress response, metabolic enzymes, the cell cycle, cell-cell communications and signal transduction. The primary purpose of this review is to examine recent findings from our group and others that focus on the molecular mechanisms of the action of inorganic fluoride in several cellular processes with respect to potential physiological and toxicological implications. This review presents an overview of the current research on the molecular aspects of fluoride exposure with emphasis on biological targets and their possible mechanisms of involvement in fluoride cytotoxicity. The goal of this review is to enhance understanding of the mechanisms by which fluoride affects cells, with an emphasis on tissue-specific events in humans. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Fluoride-releasing restorative materials and secondary caries.

Science.gov (United States)

Hicks, John; Garcia-Godoy, Franklin; Donly, Kevin; Flaitz, Catherine

2003-03-01

Secondary caries is responsible for 60 percent of all replacement restorations in the typical dental practice. Risk factors for secondary caries are similar to those for primary caries development. Unfortunately, it is not possible to accurately predict which patients are at risk for restoration failure. During the past several decades, fluoride-releasing dental materials have become a part of the dentist's armamentarium. Considerable fluoride is released during the setting reaction and for periods up to eight years following restoration placement. This released fluoride is readily taken up by the cavosurface tooth structure, as well as the enamel and root surfaces adjacent to the restoration. Resistance against caries along the cavosurface and the adjacent smooth surface has been shown in both in vitro and in vivo studies. Fluoride-releasing dental materials provide for improved resistance against primary and secondary caries in coronal and root surfaces. Plaque and salivary fluoride levels are elevated to a level that facilitates remineralization. In addition, the fluoride released to dental plaque adversely affects the growth of lactobacilli and mutans streptococci by interference with bacterial enzyme systems. Fluoride recharging of these dental materials is readily achieved with fluoridated toothpastes, fluoride mouthrinses, and other sources of topical fluoride. This allows fluoride-releasing dental materials to act as intraoral fluoride reservoirs. The improvement in the properties of dental materials with the ability to release fluoride has improved dramatically in the past decade, and it is anticipated that in the near future the vast majority of restorative procedures will employ fluoride-releasing dental materials as bonding agents, cavity liners, luting agents, adhesives for orthodontic brackets, and definitive restoratives.

Preparation of novel alginate based anion exchanger from Ulva japonica and its application for the removal of trace concentrations of fluoride from water.

Science.gov (United States)

Paudyal, Hari; Pangeni, Bimala; Inoue, Katsutoshi; Kawakita, Hidetaka; Ohto, Keisuke; Ghimire, Kedar Nath; Alam, Shafiq

2013-11-01

A green seaweed, Ulva japonica, was modified by loading multivalent metal ions such as Zr(IV) and La(III) after CaCl2 cross-linking to produce metal loaded cross-linked seaweed (M-CSW) adsorbents, which were characterized by elemental analysis, functional groups identification, and metal content determination. Maximum sorption potential for fluoride was drastically increased after La(III) and Zr(IV) loading, which were evaluated as 0.58 and 0.95 mmol/g, respectively. Loaded fluoride was quantitatively desorbed by using dilute alkaline solution for its regeneration. Mechanism of fluoride adsorption was inferred in terms of ligand exchange reaction between hydroxyl ion on co-ordination sphere of the loaded metal ions of M-CSW and fluoride ion in aqueous solution. Application of M-CSW for the treatment of actual waste plating solution exhibited successful removal of fluoride to clear the effluent and environmental standards in Japan, suggesting high possibility of its application for the treatment of fluoride rich waste water. Copyright © 2013 Elsevier Ltd. All rights reserved.

Mg-doped nano ferrihydrite - A new adsorbent for fluoride removal from aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Mohapatra, M., E-mail: mamatamohapatra@yahoo.com [Institute of Minerals and Materials Technology, Bhubaneswar 751 013, Orissa (India); Hariprasad, D.; Mohapatra, L.; Anand, S.; Mishra, B.K. [Institute of Minerals and Materials Technology, Bhubaneswar 751 013, Orissa (India)

2012-03-01

The present study evaluates synthesized Mg-doped nano ferrihydrite powder as an adsorbent for F{sup -} removal from aqueous solutions. High surface area Mg-doped ferrihydrite was prepared by co-precipitation method under controlled conditions. Samples were prepared by varying Mg content in the range of 0.39-1.12%. Preliminary test work revealed that under similar conditions, with the increase in Mg content from 0.39 to 0.98% in doped ferrihydrite, % F{sup -} adsorption increased from 66 to 91%. Hence this sample was characterized by XRD, TEM, SAED and TG-DTA. Batch adsorption experiments were carried out by varying contact time (30-480 min), initial pH (1.0-10), initial fluoride concentration (10-150 mg/L), adsorbent dose (0.5-4 g/L), temperature (20-45 Degree-Sign C) and Cl{sup -} or SO{sub 4}{sup 2-} concentrations (nil to 50 mg/L). The results showed 0.98% Mg-doped ferrihydrite to be an excellent fluoride adsorbent giving maximum adsorption capacity of 64 mg/g. The time data fitted well to pseudo second order kinetic model. The isothermal data followed Langmuir model. Thermodynamic parameters confirmed the adsorption process to be spontaneous and endothermic. 89% of fluoride could be desorbed from loaded sample using 1 M NaOH.

New transition metal oxide fluorides with ReO{sub 3}-type structure

Energy Technology Data Exchange (ETDEWEB)

Nakhal, Suliman; Lerch, Martin [Technische Universitaet Berlin (Germany). Inst. fuer Chemie

2016-08-01

The new niobium oxide fluorides MNbO{sub 2}F{sub 4} [M = (Cr, Fe)], CrNb{sub 2}O{sub 4}F{sub 5}, and Fe{sub 2}Nb{sub 3}O{sub 6}F{sub 9} were prepared by treatment of chromium or iron nitrate with Nb-containing hydrofluoric acid solutions. Crystal structures were investigated by means of X-ray powder diffraction. All new compounds can be structurally refined in the cubic ReO{sub 3}-type. The iron niobium oxide fluorides are reddish orange, and chromium containing phases exhibit a light green color. The niobium atoms are in the highest formal oxidation state.

Fluoride uptake into the developing enamel and dentine of sheep incisors following daily ingestion of fluoridated milk or water

International Nuclear Information System (INIS)

Cuttress, T.W.; Suckling, G.W.; Gao, J.; Coote, G.E.

1996-01-01

The caries preventive action of fluoride is common knowledge, although some of the mechanisms involved remain equivocal. At present, raised local levels of fluoride at, or in, the surface of tooth enamel is the most commonly accepted explanation of the anti-cariogenic action of fluoride. However, fluoride incorporated as fluorapatite into the tooth during its formation remains a possible alternative or complementary anti-cariogenic mechanism. If so, regular ingestion of fluoride during tooth formation is beneficial. Although use of fluoridated water is the preferred method in public health programmes, access to suitable potable water is required, and often this in not feasible. Fresh, preserved, or dried cow's milk products are widely used as nutritional and dietary items in most populations, particularly for young children. Milk is a practical, controllable means for regular delivery of fluoride. Processing of milk is commonly centralised and uses standardised conditions, allowing easy supplementation of fluoride for distribution to communities. The purpose of this study was to resolve the question of availability of fluoride ingested in milk compared with fluoride ingested in water by measuring fluoride deposition in the developing permanent incisors of young sheep. Incisors were analysed using a proton microprobe. (author). 18 refs., 1 tabs., 3 figs

Influence of the method of fluoride administration on toxicity and fluoride concentrations in Japanese quail

Science.gov (United States)

Fleming, W.J.; Schuler, C.A.

1988-01-01

Young Japanese quail (Coturnix japonica) were administered NaF for 16 d either in their diet or by esophageal intubation. Based on the total fluoride ion (Emg F-) intake over the l6-d experimental period, fluoride administered by intubation was at least six times more toxic than that fed in the diet. Dietary concentrations of 1,000 ppm F- (Emg F- for 16 d = approx. 144) produced no mortality, whereas intubated doses produced 73% or greater mortality in all groups administered 54 mg F- /kg/d or more (Emg F- for 16 d _ approx. 23 mg). GraphIc companson of the regression of log F- ppm in femurs/mg F- intake showed that fluoride levels in the femurs of quail administered fluoride by intubation were higher than in those administered fluoride in the diet.

Fabrication of dense panels in lithium fluoride; Fabrication de panneaux denses en fluorure de lithium

Energy Technology Data Exchange (ETDEWEB)

Farcy, P.; Roger, J.; Pointud, R.

1958-04-15

The authors report a study aimed at the fabrication of large and dense lithium fluoride panels. This sintered lithium fluoride is then supposed to be used for the construction of barriers of protection against a flow of thermal neutrons. They briefly present the raw material which is used under the form of chamotte obtained through a pre-sintering process which is also described. Grain size measurements and sample preparation are indicated. Shaping, drying, and thermal treatment are briefly described, and characteristics of the sintered product are indicated.

The preparation and characterisation of reference fission foils

International Nuclear Information System (INIS)

Audenhove, J. van; Bievre, P. de; Pauwels, J.; Peetermans, F.; Gallet, M.; Verbruggen, A.

1979-01-01

Homogeneous and accurately defined uranium and plutonium reference fissionable deposits have been prepared by vacuum deposition of fluorides. The preparation of the fluorides as well as their vacuum deposition on planetary rotating multisubstrate holders are described. The characterisation of the deposits is obtained by relative α-counting and calibration using isotope dilution mass spectrometry. The mass per square centimeter of the deposits is corrected for the border effects and the homogeneity is determined by relative α-counting of small spots. The deposits show excellent adherence and resistance to different mediums. This makes their use as permanently available reference fission foils possible. (orig.)

Levels of Antioxidant Activity and Fluoride Content in Coffee Infusions of Arabica, Robusta and Green Coffee Beans in According to their Brewing Methods.

Science.gov (United States)

Wolska, J; Janda, Katarzyna; Jakubczyk, K; Szymkowiak, M; Chlubek, D; Gutowska, I

2017-10-01

Coffee is a rich source of dietary antioxidants, and this property links with the fact that coffee is one of the world's most popular beverages. Moreover, it is a source of macro- and microelements, including fluoride. The aim of this work was to determine antioxidant activity of coffee beverages and fluoride content depending on different coffee species and conditions of brewing. Three species of coffee, arabica, robusta and green coffee beans obtained from retail stores in Szczecin (Poland) were analyzed. Five different techniques of preparing drink were used: simple infusion, french press, espresso maker, overflow espresso and Turkish coffee. Antioxidant potential of coffee beverages was investigated spectrophotometrically by DPPH method. Fluoride concentrations were measured by potentiometric method with a fluoride ion-selective electrode. Statistical analysis was performed using Stat Soft Statistica 12.5. Antioxidant activity of infusions was high (71.97-83.21% inhibition of DPPH) depending on coffee species and beverage preparing method. It has been shown that the method of brewing arabica coffee and green coffee significantly affects the antioxidant potential of infusions. The fluoride concentration in the coffee infusions changed depending, both, on the species and conditions of brewing, too (0.013-0.502 mg/L). Methods of brewing didn't make a difference to the antioxidant potential of robusta coffee, which had also the lowest level of fluoride among studied species. Except overflow espresso, the fluoride content was the highest in beverages from green coffee. The highest fluoride content was found in Turkish coffee from green coffee beans.

LLL2: an international global level questionnaire on toothbrushing and use of fluoride toothpaste.

Science.gov (United States)

Llodra, Juan Carlos; Phantumvanit, Prathip; Bourgeois, Denis M; Horn, Virginie

2014-10-01

To determine the evolution of toothbrushing frequency and use of fluoridetoothpaste in the FDI-Unilever partnership Live.Learn.Laugh. phase 2 programme using a self-reported questionnaire. The study was conducted in 23 countries. The key focus of this partnership was to educate people about the benefits of twice-daily brushing with fluoride toothpaste and to support people in adopting this important oral health behaviour. The partnership offers a choice of four project options to the local partnership team of the National Dental Association and local Unilever-operating companies. A self-report questionnaire was used in all participating subjects in local projects to evaluate the brushing frequency, the brushing timing and the use of fluoride toothpaste. After implementation of the project interventions, a clear improvement in the reported frequency of brushing twice a day, regardless of the type of project, was observed. Subjects also increased day and night brushing and the use of fluoride toothpaste. The strategy of using mothers to increase healthy behaviours in oral health achieved the greatest increase in twice-daily toothbrushing, followed by the intervention in schools. © 2014 FDI World Dental Federation.

Application of Titanium Compounds to Reduce Fluoride Ion in Water Resources with High Fluoride Ion Contents

Directory of Open Access Journals (Sweden)

Fariborz Riahi

2005-06-01

Full Text Available The present work describes studies on the sorption of fluoride ions from water by titanium compounds used in water treatment to reduce fluoride content in water resources. There are different methods of reducing fluoride ion in water, each associated with specific problems such as secondary contamination, environmental contamination, high costs, or the need for primary and secondary treatment. In this study, application of titanium sulfate and Metatitanic acid produced from titanium ore concentrate (ileminite is investigated in the removal of fluoride ion and the possibility of complete purification of fluorine containing wastewater is examined to determine the optimal conditions. Metatitanic acid has a great sorption property for fluoride ion. Also titanium sulfate is a suitable and more effective material for this purpose. Efficiency of this material in reducing fluoride ion content is 99.9% and it is possible to refresh sorbet material for reuse without problems arising from Ti+4 ion contamination.

Changing use and knowledge of fluoride toothpaste by schoolchildren, parents and schoolteachers in Beijing, China

DEFF Research Database (Denmark)

Liu, Min; Zhu, Ling; Zhang, BoXue

2007-01-01

OBJECTIVE: To assess the oral hygiene practices, current use of and knowledge about fluoride toothpaste among schoolchildren, parents, and schoolteachers; to describe the attitudes of parents and schoolteachers in relation to improving schoolchildren's oral health. DESIGN: Cross-sectional study....... PARTICIPANTS: 1,557 schoolchildren, 1,132 parents, and 352 schoolteachers were recruited by multistage stratified sampling procedure in a district of Beijing, China. METHODS: Self-completed questionnaire. RESULTS: The percentage of schoolchildren, parents, and schoolteachers who actually used fluoride...... toothpaste was 88%, 86%, and 87%, respectively, and 74-78% of the respondent groups brushed their teeth twice a day or more. 64% of schoolchildren, 73% of parents, and 74% of schoolteachers confirmed the caries preventive effect of fluoride toothpaste. Toothpaste recommended by oral health professional...

Toxic effects of fluoride on organisms.

Science.gov (United States)

Zuo, Huan; Chen, Liang; Kong, Ming; Qiu, Lipeng; Lü, Peng; Wu, Peng; Yang, Yanhua; Chen, Keping

2018-04-01

Accumulation of excess fluoride in the environment poses serious health risks to plants, animals, and humans. This endangers human health, affects organism growth and development, and negatively impacts the food chain, thereby affecting ecological balance. In recent years, numerous studies focused on the molecular mechanisms associated with fluoride toxicity. These studies have demonstrated that fluoride can induce oxidative stress, regulate intracellular redox homeostasis, and lead to mitochondrial damage, endoplasmic reticulum stress and alter gene expression. This paper reviews the present research on the potential adverse effects of overdose fluoride on various organisms and aims to improve our understanding of fluoride toxicity. Copyright © 2018 Elsevier Inc. All rights reserved.

Mesoporous zeolite and zeotype single crystals synthesized in fluoride media

DEFF Research Database (Denmark)

Egeblad, Kresten; Kustova, Marina; Klitgaard, Søren Kegnæs

2007-01-01

We report the synthesis and characterization of a series of new mesoporous zeolite and zeotype materials made available by combining new and improved procedures for directly introducing carbon into reaction mixtures with the fluoride route for conventional zeolite synthesis. The mesoporous...... materials were all prepared by hydrothermal crystallization of gels adsorbed on carbon matrices which were subsequently removed by combustion. The procedures presented here resulted in mesoporous zeolite and zeotypes materials with MFI, MEL, BEA, AFI and CHA framework structures. All samples were...... characterized by XRPD, SEM, TEM and N-2 physisorption measurements. For the zeolite materials it A as found that mesoporous MFI and MEL structured single crystals could indeed be crystallized from fluoride media using an improved carbon-templating approach. More importantly, it was found that mesoporous BEA...

Magnetic interactions through fluoride

DEFF Research Database (Denmark)

Pedersen, Kasper Steen; Sigrist, Marc; Weihe, Høgni

2014-01-01

support the parameter values and resolve |E| ≈ 0.04 cm(-1). The exchange coupling constant (J) is 1 order of magnitude smaller than that found in comparable systems with linear oxide bridging but comparable to typical magnitudes through cyanide, thus underlining the potential of fluoride complexes......The nature of the magnetic interaction through fluoride in a simple, dinuclear manganese(III) complex (1), bridged by a single fluoride ion in a perfectly linear fashion, is established by experiment and density functional theory. The magnitude of the antiferromagnetic exchange interaction...

Estimation of Fluoride Concentration of Various Citrus and Non-Citrus Fruits Commonly Consumed and Commercially Available in Mathura City

Directory of Open Access Journals (Sweden)

Navin Anand Ingle

2013-01-01

Full Text Available Background: Since fluoride is available from various sources, the total ingestion of fluoride by a person should be estimated taking into consideration the fluoride consumed from all the sources including fruits. There are very few epidemiological studies carried out associated with fluoride estimation in fruit samplesand especially in the Indian scenario Objective: To estimate and compare the fluoride concentration of different commercially available citrus and non-citrus fruits in Mathura city. Materials & Method: Fifteen different types of fruits commercially available and consumed by people ofMathura City were collected. Out of the 15 fruit samples 5 were citrus fruits and 10 were non-citrus fruits. The fluoride estimation of fruit samples was done at Central Laboratory,Lucknow. Juices of all 15 fruit samples were prepared, from each sample 10 ml of juice was measured and fluoride testing of each sample was carried out by using Orion 4 star -ion electrode analyzer. The collected data was analyzed using the statistical software program SPSS, version 17. Results: The fluoride concentration in citrus fruits ranged from 0.04ppm (Orange to 0.08 ppm (Tomato while in non-citrus fruits it ranged from 0.04ppm (chikoo to 0.18 ppm (Guava. No significant difference was observed between the mean fluoride concentration of citrus and non citrus fruits. Conclusions: Both citrus and non citrus fruits have fluorides. Guava was found to have the maximumamount of fluoridecontent (0.18 ppm among both the citrus and non citrus fruits.

Tamarind (Tamarindus indica) fruit shell carbon: A calcium-rich promising adsorbent for fluoride removal from groundwater

International Nuclear Information System (INIS)

Sivasankar, V.; Rajkumar, S.; Murugesh, S.; Darchen, A.

2012-01-01

Highlights: ► The carbonization of Tamarind fruit shell improved its defluoridation efficiency. ► Calcium carbonate particles were involved in the defluoridation process. ► Adsorbent dose, pH, and fluoride concentration showed significant effects. ► Maximum adsorption of fluoride was achieved at pH 7–8. ► Prepared carbons were efficient in treating three natural waters. - Abstract: Tamarindus indica fruit shells (TIFSs) are naturally calcium rich compounds. They were impregnated with ammonium carbonate and then carbonized, leading to ammonium carbonate activated ACA-TIFS carbon. The resulting materials and carbon arising from virgin fruit shells V-TIFS were characterized and assayed as adsorbent for the removal of fluoride anions from groundwater. The fluoride scavenging ability of TIFS carbons was due to naturally dispersed calcium compounds. X-ray diffraction (XRD) showed that TIFS carbon contained a mixture of calcium oxalate and calcium carbonate. Batch studies on the fluoride removal efficiency of TIFS carbons with respect to contact time, pH, initial fluoride concentration, and co-ion interference were conducted. Applicability of various kinetic models (viz., pseudo-first-order, pseudo-second-order, intra-particle diffusion and Elovich) and sorption isotherms were tested for batch techniques. The fluoride removal capacity of TIFS carbons was found to be 91% and 83% at a pH of 7.05 for V-TIFS and ACA-TIFS carbons, respectively. The practical applicability of TIFS carbons using groundwater samples was approved. The fluoride removal was greater in groundwater without hydrogen carbonate ions than those containing these ions. The characterizations of fluoride unloaded and loaded TIFS carbons were done by SEM and XRD studies.

[The effect of fluoride-containing tooth paste on dental plaque and on fluoride level in the mouth].

Science.gov (United States)

Oomori, H

1989-01-01

Various kinds of fluoride have been used for a long time and there are many reports concerning fluorides and their effects. Recently, the caries-inhibiting action of fluoride-containing tooth paste has been given much attention. In this study, I tried to clarify the residual time and amount of fluoride derived from the fluoride-containing tooth paste in the mouth, as well as to assess possible variation in bacterial composition in the dental plaque bacteriologically and biochemically. In the study on the fluoride clearance from the mouth, both 1.0 g and 0.5 g of paste showed the same reduction rates; and about an 80% reduction was recognized between the value at 3 minutes and that at 30 minutes, and about a 40% reduction from the 30-minute to the 60-minute interval. Next, a study on the variation in plaque bacteria was carried out. The total number of the CFU on each plate was not different between samples obtained before and after the use of the tooth paste; moreover, no difference was noted between aerobic and anaerobic culture. However, when plaque before and after brushing with fluoride-containing tooth paste were cultured in 10% sucrose solution, the differences of acid production such as lactic acid, acetic acid, and formic acid were demonstrated. Namely, these acid productions were inhibited after the use of fluoride, especially lactic acid was strongly inhibited. On the other hand, when Str. mutans from the plaque obtained after the use of fluoride-containing tooth paste was cultured in fluoride-free BHI broth, the inhibition of acid from carbohydrates was not shown clearly.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis of an oxo trialkyl tungsten fluoride complex and its dual reactivity with silica dehydroxylated at high temperature

KAUST Repository

Merle, Nicolas

2018-05-22

The novel complex W (=O)Np3F has been prepared by fluorination of the corresponding chloride counterpart with AgBF4. The reactivity of this complex with silica dehydroxylated at 700 °C afforded a well-defined silica supported monopodal tungsten oxo trialkyl surface species (≡SiO)W (=O)Np3. The reaction proceeds both through silanolysis of the W-F bond and opening of a siloxane bridge, with formation of a Si-F fragment, thanks to the affinity of silicon for fluoride. The resulting surface species was characterized by elemental analysis, DRIFT, solid state NMR and EXAFS spectroscopy. This material presenting fluorine on its surface shows an enhanced catalytic activity in propylene self-metathesis compared to its monopodal counterpart (≡SiO)W (=O)Np3 (prepared from W (=O)Np3Cl) suggesting that the Si-F in a close vicinity to the W decreases the electron density of the W and thus increases its reactivity towards the olefinic substrate.

Synthesis of an oxo trialkyl tungsten fluoride complex and its dual reactivity with silica dehydroxylated at high temperature

KAUST Repository

Merle, Nicolas; Mazoyer, Etienne; Szeto, Kai C.; Rouge, Pascal; de Mallmann, Aimery; Berrier, Elise; Delevoye, Laurent; Gauvin, Ré gis M.; Nicholas, Christopher P.; Basset, Jean-Marie; Taoufik, Mostafa

2018-01-01

The novel complex W (=O)Np3F has been prepared by fluorination of the corresponding chloride counterpart with AgBF4. The reactivity of this complex with silica dehydroxylated at 700 °C afforded a well-defined silica supported monopodal tungsten oxo trialkyl surface species (≡SiO)W (=O)Np3. The reaction proceeds both through silanolysis of the W-F bond and opening of a siloxane bridge, with formation of a Si-F fragment, thanks to the affinity of silicon for fluoride. The resulting surface species was characterized by elemental analysis, DRIFT, solid state NMR and EXAFS spectroscopy. This material presenting fluorine on its surface shows an enhanced catalytic activity in propylene self-metathesis compared to its monopodal counterpart (≡SiO)W (=O)Np3 (prepared from W (=O)Np3Cl) suggesting that the Si-F in a close vicinity to the W decreases the electron density of the W and thus increases its reactivity towards the olefinic substrate.

Physiologic Conditions Affect Toxicity of Ingested Industrial Fluoride

Directory of Open Access Journals (Sweden)

Richard Sauerheber

2013-01-01

Full Text Available The effects of calcium ion and broad pH ranges on free fluoride ion aqueous concentrations were measured directly and computed theoretically. Solubility calculations indicate that blood fluoride concentrations that occur in lethal poisonings would decrease calcium below prevailing levels. Acute lethal poisoning and also many of the chronic effects of fluoride involve alterations in the chemical activity of calcium by the fluoride ion. Natural calcium fluoride with low solubility and toxicity from ingestion is distinct from fully soluble toxic industrial fluorides. The toxicity of fluoride is determined by environmental conditions and the positive cations present. At a pH typical of gastric juice, fluoride is largely protonated as hydrofluoric acid HF. Industrial fluoride ingested from treated water enters saliva at levels too low to affect dental caries. Blood levels during lifelong consumption can harm heart, bone, brain, and even developing teeth enamel. The widespread policy known as water fluoridation is discussed in light of these findings.

Physiologic conditions affect toxicity of ingested industrial fluoride.

Science.gov (United States)

Sauerheber, Richard

2013-01-01

The effects of calcium ion and broad pH ranges on free fluoride ion aqueous concentrations were measured directly and computed theoretically. Solubility calculations indicate that blood fluoride concentrations that occur in lethal poisonings would decrease calcium below prevailing levels. Acute lethal poisoning and also many of the chronic effects of fluoride involve alterations in the chemical activity of calcium by the fluoride ion. Natural calcium fluoride with low solubility and toxicity from ingestion is distinct from fully soluble toxic industrial fluorides. The toxicity of fluoride is determined by environmental conditions and the positive cations present. At a pH typical of gastric juice, fluoride is largely protonated as hydrofluoric acid HF. Industrial fluoride ingested from treated water enters saliva at levels too low to affect dental caries. Blood levels during lifelong consumption can harm heart, bone, brain, and even developing teeth enamel. The widespread policy known as water fluoridation is discussed in light of these findings.

Preparation and evaluation of curcumin-loaded self-assembled micelles.

Science.gov (United States)

Wang, Lu-Lu; He, Dan-Dan; Wang, Shu-Xia; Dai, Yun-Hao; Ju, Jian-Ming; Zhao, Cheng-Lei

2018-04-01

Curcumin being used to treat various chronic diseases while its poor bioavailability issue limited its wide clinical application as a therapeutic agent. The aim of this work was to prepare curcumin-loaded self-assembled micelles using soluplus and solutol ® HS15 (SSCMs) to enhance curcumin's solubility and thus oral bioavailability. Optimum formulation was investigated and the optimized ratio of drugs and excipients was obtained and the SSCMs were prepared via ethanol solvent evaporation method. The optimal SSCMs were characterized by transmission electron microscopy, drug content analysis including loading efficiency (LE%) and entrapment efficiency (EE%), and the cumulative amount of curcumin released from the micelles were all calculated using HPLC method. The in vitro cytotoxicity and the permeability of SSCMs were measured by Caco-2 cell monolayers and the oral bioavailability was evaluated by SD rats. The solubility of curcumin in self-assembled micelles was dramatically increased by 4200 times as compared to free curcumin. Caco-2 cells transport experiment exhibited that while soluplus and solutol ® HS15 were self-assembled into micelles, it could not only promote the permeability of curcumin across membrane for better absorption, but also could restrain the curcumin pumped outside due to the role of P-gp efflux mechanism of soluplus and solutol ® HS15. Furthermore, the prepared SSCMs formulation was almost nontoxic and had safety performance on Caco-2 cells model. Moreover, curcumin's oral bioavailability of SSCMs formulation in SD rats had doubled than that of free curcumin. The prepared SSCMs were characterized by PS, PDI, LE%, EE% data analysis. After the soluplus and solutol ® HS15 were self assembled into micelles, both the solubility and membrane permeability of curcumin were evaluated to have been enhanced, as well as the effect of efflux pump of curcumin was inhibited, hence to promote oral absorption and generate an increased bioavailability.

On some derived compounds of fluorides of Cerium III or IV: defined compounds and non stoichiometric phases

International Nuclear Information System (INIS)

Besse, Jean-Pierre

1968-01-01

This research study addresses the study of rare earth fluorides. It reports the preparation and study of new fluoro-cerates (IV) in order to complete the set of already known compounds (ammonium fluoro-cerate, and alkaline earth compounds), the study of binary CeF 3 binary systems, monovalent and divalent fluorides, and CeF 3 -NF 2 -N'F ternary systems, and the study of non stoichiometric phases in CeF 3 oxides, sulphides and selenides [fr

Preparation of Nanofibrous Silver/Poly(vinylidene fluoride) Composite Membrane with Enhanced Infrared Extinction and Controllable Wetting Property.

Science.gov (United States)

Ren, Da-Ming; Huang, Hua-Kun; Yu, Yun; Li, Zeng-Tian; Jiang, Li-Wang; Chen, Shui-Mei; Lam, Kwok-Ho; Lin, Bo; Shi, Bo; He, Fu-An; Wu, Hui-Jun

2018-05-01

Nanofibrous silver (Ag)/poly(vinylidene fluoride) (PVDF) composite membranes were obtained from a two-step preparation method. In the first step, the electrospun silver nitrate (AgNO3)/PVDF membranes were prepared and the influence of the AgNO3 content on the electrospinning process was studied. According to scanning electron microscopy (SEM) results, when the electrospinning solution contained AgNO3 in the range between 3 to 7 wt.%, the nanofiber morphologies can be obtained. In the second step, the electrospun AgNO3/PVDF membranes were reduced by sodium borohydride to form the nanofibrous Ag/PVDF composite membranes. The resultant composite membranes were characterized by SEM, X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), differential scanning calorimetry, X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared. The XRD, XPS, and EDS characterizations proved the existence of Ag in the nanofibrous Ag/PVDF composite membranes. The crystallinity degree of PVDF for composite membranes declined with the increase in Ag content. More importantly, the nanofibrous Ag/PVDF composite membranes had obviously higher Rosseland extinction coefficients and lower thermal radiative conductivities in comparison with electrospun PVDF membrane, which demonstrates that such composite membranes with high porosity, low density, and good water vapor permeability are promising thermal insulating materials to block the heat transfer resulting from thermal radiation. In addition, three different methods for surface modification have been used to successfully improve the hydrophobicity of nanofibrous Ag/PVDF composite membranes.

Potential fluoride toxicity from oral medicaments: A review.

Science.gov (United States)

Ullah, Rizwan; Zafar, Muhammad Sohail; Shahani, Nazish

2017-08-01

The beneficial effects of fluoride on human oral health are well studied. There are numerous studies demonstrating that a small amount of fluoride delivered to the oral cavity decreases the prevalence of dental decay and results in stronger teeth and bones. However, ingestion of fluoride more than the recommended limit leads to toxicity and adverse effects. In order to update our understanding of fluoride and its potential toxicity, we have described the mechanisms of fluoride metabolism, toxic effects, and management of fluoride toxicity. The main aim of this review is to highlight the potential adverse effects of fluoride overdose and poorly understood toxicity. In addition, the related clinical significance of fluoride overdose and toxicity has been discussed.

Effects of hydrogen fluoride on plants

Energy Technology Data Exchange (ETDEWEB)

Yamazoe, F

1970-07-15

Symptoms of fluorosis in plants are chlorotic markings around the tip or edges of young leaves. Examples of damage to plants and livestock by fluorides are listed, including the retarded growth of silkworms fed on mulberry leaves polluted by more than 30 ppm fluorides. Plants can be classified into six groups according to their resistance to hydrogen fluoride. Threshold values of the fluoride concentration range from 5-10 ppb for the plants. Gladiolus is normally employed as a plant indicator for hydrogen fluoride and silkworms as indicator insects. The relationship between plant damage by fluorides and exposure time, density, soil, fertilizer, meteorology and location are examined. Several preventive measures are listed, including the spraying of water or lime on plant leaves. It is concluded that the establishment of an environmental standard is difficult because of the extremely high sensitivity of the plants to the gas. 8 references.

Preparation process of a stable non radioactive carrier intended for radiodiagnosis

International Nuclear Information System (INIS)

Molinski, V.J.; Wilczewski, J.A.

1976-01-01

The description is given of a stable non radioactive carrier with a pH of around 2 and around 4, for cardiological studies, exploring the blood in circulation and exploring the brain, after labelling with sup(99m)Tc. It includes human serum albumin (SAH) and stannous tartrate, the proportion in weight between the SAH and stannous tartrate being between around 50:1 and around 150:1 [fr

Determination of lithium in organic matrix by potentiometric titration using fluoride ion selective electrode

International Nuclear Information System (INIS)

Govindan, R.; Alamelu, D.; Shah, Raju; Aggarwal, S.K.

2008-01-01

A method has been developed for the determination of lithium (Li) present in organic matrix containing hexa methylene tetramine (HMTA) and urea used in the sol-gel process for preparing lithium titanate microspheres, using fluoride ion selective electrode and potentiometric end point. Lithium is present in the wash solutions of the Sol-Gel process employed for the preparation of lithium titanate microspheres, proposed to be used in TBM (Test Blanket Module) of International Thermonuclear Experimental Reactor (ITER) project. Methods such as ICP-AES, AAS etc. used in aqueous solutions cannot be employed directly for lithium determination in organic matrix containing hexa methylene tetramine (HMTA), urea, NH 4 NO 3 , NH 4 Cl etc. A potentiometric method using a combination fluoride ion selective electrode for end point detection was developed and has been employed for lithium determination in the process streams from sol-gel process. The method is simple and rapid and an accuracy of about 0.5 % was achieved for the determination of Li in the range of 1 to 20 mg. The method is based on the complexation of Li by adding a known excess of NH 4 F solution, followed by potentiometric end point detection using fluoride ISE

Effect of Fluoride and Bentonite on Biochemical Aspects of Oxidative Stress in Pisum sativum L.

Directory of Open Access Journals (Sweden)

Martyna Śnioszek

2018-03-01

Full Text Available Fluoride is regarded as one of the strongest oxidants, which causes oxidative changes in cells of living organisms. It may both increase the content of reactive oxygen species and inhibit the activity of antioxidative enzyme. In recent years, many researchers successfully used the properties of clay minerals in the sorption of fluoride ion from water. This raises the question of the possibility of limiting the effect of fluorine on the negative changes in plants by adding bentonite to soil. A two-year pot experiment was carried out in the Greenhouse of West Pomeranian University of Technology in Szczecin, on loamy sand and sandy loam. Each sample of soil was mixed with three different concentrations of bentonite – 1, 5, 10% of dry weight (DW of the soil and then treated with 30 mmol of F- per 1 kg of dry weight of the soil in a form of NaF solution. A control series was prepared for each soil, to which no additives were added. The medium prepared in such way was transferred to plastic pots (3 kg each and seeded with 16 pea seeds of Pisum sativum. In three phases of pea development (4 leaves unfolded, flowering and development of fruit, fresh leaf samples were collected and the concentrations of ascorbic acid, reduced glutathione, total flavonoids and total polyphenols were measured. Sodium fluoride introduced to the soil changed the level of antioxidant parameters in the plant, which may suggest that fluoride is involved in the formation of reactive oxygen species, resulting in oxidative stress. Bentonite in a dosage of 10% reduced the toxic effects of fluoride on the oxidative balance and morphological changes in the plant, which was observed especially for loamy sand, naturally poor in clay minerals.

Sirt1 overexpression suppresses fluoride-induced p53 acetylation to alleviate fluoride toxicity in ameloblasts responsible for enamel formation.

Science.gov (United States)

Suzuki, Maiko; Ikeda, Atsushi; Bartlett, John D

2018-03-01

Low-dose fluoride is an effective caries prophylactic, but high-dose fluoride is an environmental health hazard that causes skeletal and dental fluorosis. Treatments to prevent fluorosis and the molecular pathways responsive to fluoride exposure remain to be elucidated. Previously we showed that fluoride activates SIRT1 as an adaptive response to protect cells. Here, we demonstrate that fluoride induced p53 acetylation (Ac-p53) [Lys379], which is a SIRT1 deacetylation target, in ameloblast-derived LS8 cells in vitro and in enamel organ in vivo. Here we assessed SIRT1 function on fluoride-induced Ac-p53 formation using CRISPR/Cas9-mediated Sirt1 knockout (LS8 Sirt/KO ) cells or CRISPR/dCas9/SAM-mediated Sirt1 overexpressing (LS8 Sirt1/over ) cells. NaF (5 mM) induced Ac-p53 formation and increased cell cycle arrest via Cdkn1a/p21 expression in Wild-type (WT) cells. However, fluoride-induced Ac-p53 was suppressed by the SIRT1 activator resveratrol (50 µM). Without fluoride, Ac-p53 persisted in LS8 Sirt/KO cells, whereas it decreased in LS8 Sirt1/over . Fluoride-induced Ac-p53 formation was also suppressed in LS8 Sirt1/over cells. Compared to WT cells, fluoride-induced Cdkn1a/p21 expression was elevated in LS8 Sirt/KO and these cells were more susceptible to fluoride-induced growth inhibition. In contrast, LS8 Sirt1/over cells were significantly more resistant. In addition, fluoride-induced cytochrome-c release and caspase-3 activation were suppressed in LS8 Sirt1/over cells. Fluoride induced expression of the DNA double strand break marker γH2AX in WT cells and this was augmented in LS8 Sirt1/KO cells, but was attenuated in LS8 Sirt1/over cells. Our results suggest that SIRT1 deacetylates Ac-p53 to mitigate fluoride-induced cell growth inhibition, mitochondrial damage, DNA damage and apoptosis. This is the first report implicating Ac-p53 in fluoride toxicity.

Eukaryotic resistance to fluoride toxicity mediated by a widespread family of fluoride export proteins

OpenAIRE

Li, Sanshu; Smith, Kathryn D.; Davis, Jared H.; Gordon, Patricia B.; Breaker, Ronald R.; Strobel, Scott A.

2013-01-01

Although fluoride is plentiful in the environment and is commonly used at high concentrations in oral hygiene products, little has been known about how biological systems overcome the toxic effects of this anion. We demonstrate that a protein called FEX in many fungi is essential for cell survival in the presence of high fluoride concentrations. The protein is required for the rapid expulsion of cytoplasmic fluoride, indicating that many eukaryotic species that carry FEX genes likely avoid fl...

Impact of Dental Fluorosis, Socioeconomic Status and Self-Perception in Adolescents Exposed to a High Level of Fluoride in Water.

Science.gov (United States)

Molina-Frechero, Nelly; Nevarez-Rascón, Martina; Nevarez-Rascón, Alfredo; González-González, Rogelio; Irigoyen-Camacho, María Esther; Sánchez-Pérez, Leonor; López-Verdin, Sandra; Bologna-Molina, Ronell

2017-01-12

Objective : To identify adolescents' self-perception of dental fluorosis from two areas with different socioeconomic levels. Methods : A cross-sectional, descriptive study was conducted with 15-year-old youths by applying a questionnaire designed and validated to assess self-perceptions of dental fluorosis in two areas with different socioeconomic statuses (SESs). Fluorosis was clinically evaluated by applying the Thylstrup and Fejerkov (TF) index on the upper front teeth. Results : A total of 308 adolescents were included in the study. The medium-SES population, which was exposed to 2.5 ppm of fluoride in water, and the low-SES population, which was exposed to 5.1 ppm, presented the following levels of dental fluorosis: TF 2-3 (50%), TF 4-5 (45.6%) and TF 6-7 (4.4%) for medium SES and TF 2-3 (12.3%), TF 4-5 (67.1%) and TF 67 (20.6%) for low SES. A significant association was found between self-perception and dental fluorosis in those with medium and low SESs ( p self-perception, with a 6-7 TF level for concerns about color (OR = 1.6), smile (OR = 1.2) and appearance (OR = 3.36). Conclusions : Self-perceptions of dental fluorosis affect adolescents such that adolescents with a medium SES have more negative perceptions than those with a low SES. Such perceptions increase as the TF index increases.

Gramicidin D enhances the antibacterial activity of fluoride

OpenAIRE

Nelson, James W.; Zhou, Zhiyuan; Breaker, Ronald R.

2014-01-01

Fluoride is a toxic anion found in many natural environments. One of the major bacterial defenses against fluoride is the cell envelope, which limits passage of the membrane-impermeant fluoride anion. Accordingly, compounds that enhance the permeability of bacterial membranes to fluoride should also enhance fluoride toxicity. In this study, we demonstrate that the pore-forming antibiotic gramicidin D increases fluoride uptake in B. subtilis and that the antibacterial activity of this compound...

Electrodeposition of some metals and niobium superconducting alloys from molten fluorides

International Nuclear Information System (INIS)

Cohen, U.

1978-01-01

The major goal of this thesis was to study the feasibility of electrodeposition from molten fluorides of the pure elements niobium, aluminium, tin, germanium and silicon, and the niboium superconducting intermetallic compounds with these elements, and to prepare and study films of these materials in the form of coherent and uniform coatings. Decomposition potential measurements with a gold anode were carried out on the alkali fluoride solvent and the fluoride salt solutions of niobium, aluminum, tin, and germanium to provide important initial thermodynamic data. Attempts to codeposit niobium and aluminum invariably failed, niobium being the exclusive deposit in all cases. Codeposition of niobium--tin alloys was demonstrated. Of the four intermetallic compounds of the niobium--germanium system, three were obtained as single-phase coatings. The superconducting compound (A15 phase) was not successfully electrodeposited in a single-phase form. It was obtained, however, in phase-mixture coatings. Application of alternating square wave pulses produced substantial changes in the morphology of niobium deposits. Silicon electrocrystallization epitaxy (ECE) was demonstrated for the first time. Uniform, coherent, and well adherent coatings of polycrystalline Si with a grain diameter of up to 40 to 50 μm were plated onto nonalloying metal substrates, such as silver and tungsten.These processes offer some attractive features for both integrated circuit technology and silicon solar cell fabrication. Aluminum, tin, and germanium were also electrodeposited from molten fluorides

Accumulation of fluoride by plants and vegetables

International Nuclear Information System (INIS)

Njenga, L.W.; Kariuki, D.N.

1994-01-01

Fluoride in plant and vegetable samples has been determined using ion selective electrode. The analysis was carried out after ashing the sample on an open flame, adding perchloric acid and allowing the hydrogen fluoride to diffuse into sodium hydroxide layer.The results obtained show that kale and pumpkins can accumulate more than ten times their normal values of fluoride while plants were found to accumulate upto 100μg/g fluoride when exposed to highlevels of fluoride in water or soil. (author)

Gramicidin D enhances the antibacterial activity of fluoride.

Science.gov (United States)

Nelson, James W; Zhou, Zhiyuan; Breaker, Ronald R

2014-07-01

Fluoride is a toxic anion found in many natural environments. One of the major bacterial defenses against fluoride is the cell envelope, which limits passage of the membrane-impermeant fluoride anion. Accordingly, compounds that enhance the permeability of bacterial membranes to fluoride should also enhance fluoride toxicity. In this study, we demonstrate that the pore-forming antibiotic gramicidin D increases fluoride uptake in Bacillus subtilis and that the antibacterial activity of this compound is potentiated by fluoride. Polymyxin B, another membrane-targeting antibiotic with a different mechanism of action, shows no such improvement. These results, along with previous findings, indicate that certain compounds that destabilize bacterial cell envelopes can enhance the toxicity of fluoride. Copyright © 2014 Elsevier Ltd. All rights reserved.

Potential fluoride toxicity from oral medicaments: A review

Directory of Open Access Journals (Sweden)

Rizwan Ullah

2017-08-01

Full Text Available The beneficial effects of fluoride on human oral health are well studied. There are numerous studies demonstrating that a small amount of fluoride delivered to the oral cavity decreases the prevalence of dental decay and results in stronger teeth and bones. However, ingestion of fluoride more than the recommended limit leads to toxicity and adverse effects. In order to update our understanding of fluoride and its potential toxicity, we have described the mechanisms of fluoride metabolism, toxic effects, and management of fluoride toxicity. The main aim of this review is to highlight the potential adverse effects of fluoride overdose and poorly understood toxicity. In addition, the related clinical significance of fluoride overdose and toxicity has been discussed.

Growth of fluoride treated Kalanchoe pinnata plants

Energy Technology Data Exchange (ETDEWEB)

Johnson, H N; Applegate, H G

1962-01-01

Kalanchoe pinnata plants can absorb fluoride through roots. The absorption is related to the amount of fluoride applied to the soil. There appeared to be a relationship between the amount of fluoride adsorbed and the subsequent growth of the plants. Plants which adsorbed the largest amounts of fluoride had the greatest increase in growth.

Facile preparation of luminescent and intelligent gold nanodots based on supramolecular self-assembly

International Nuclear Information System (INIS)

Shi Yunfeng; Li Sujuan; Zhou Yahui; Zhai Qingpan; Hu Mengyue; Cai Fensha; Du Jimin; Liang Jiamiao; Zhu Xinyuan

2012-01-01

A new strategy for preparing luminescent and intelligent gold nanodots based on supramolecular self-assembly is described in this paper. The supramolecular self-assembly was initiated through electrostatic interactions and ion pairing between palmitic acid and hyperbranched poly(ethylenimine). The resulting structures not only have the dynamic reversible properties of supramolecules but also possess torispherical and highly branched architectures. Thus they can be regarded as a new kind of ideal nanoreactor for preparing intelligent Au nanodots. By preparing Au nanodots within this kind of supramolecular self-assembly, the environmental sensitivity of intelligent polymers and the optical, electrical properties of Au nanodots can be combined, endowing the Au nanodots with intelligence. In this paper, a supramolecular self-assembly process based on dendritic poly(ethylenimine) and palmitic acid was designed and then applied to prepare fluorescent and size-controlled Au nanodots. The pH response of Au nanodots embodied by phase transfer from oil phase to water phase was also investigated. (paper)

Well Waters Fluoride in Enugu, Nigeria

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ISI Ogbu

2012-03-01

Full Text Available Abnormal fluoride levels in drinking water have been associated with adverse health effects. To determine the fluoride content of well waters in Enugu, southeastern Nigeria, water samples from 50 artisan wells chosen by multistage sampling procedure from the 5 zones of Enugu municipality were analyzed in duplicates for their fluoride content. The zonal mean values were 0.60, 0.70, 0.62, 0.62, and 0.63 mg/L for Abakpa Nike, Achara Layout, Obiagu/ Ogui, Trans Ekulu and Uwani, respectively (p<0.05. The mean value for the whole city was 0.63 mg/L. Although, the mean level of fluoride recorded in this study is currently within safe limits (1.5 mg/L, WHO 2011, it is important to monitor continuously the fluoride content of well waters in the municipality in view of the increasing industrial activities going on in the city and heavy reliance on well water for domestic purposes and the widespread use of consumer products containing fluoride.

The effects of fluoride, strontium, theobromine and their combinations on caries lesion rehardening and fluoridation.

Science.gov (United States)

Lippert, Frank

2017-08-01

The aim was to investigate the effects of fluoride, strontium, theobromine and their combinations on caries lesion rehardening and fluoridation (EFU) under pH cycling conditions. Human enamel specimens were demineralized at 37°C for 24h using a pH 5.0 solution containing 50mM lactic acid and 0.2% Carbopol 907 which was 50% saturated with respect to hydroxyapatite. Lesions were assigned to nine treatment groups (n=16) based on Knoop surface microhardness indentation length. aqueous solutions were: placebo, 11.9mM sodium fluoride (F), 23.8mM sodium fluoride (2×F), 1.1mM strontium chloride hexahydrate (Sr), 1.1mM F theobromine, Sr+theobromine, F+Sr, F+theobromine, F+Sr+theobromine. Lesions were pH cycled for 5d (daily protocol: 3×1min-treatment; 2×60min-demineralization; 4×60min & overnight-artificial saliva). Knoop indentation length was measured again and%surface microhardness recovery (%SMHr) calculated. EFU was determined using the acid-etch technique. Data were analysed using ANOVA. Model showed fluoride dose-response for both variables (2×F>F>placebo). For%SMHr, F+Sr+/-theobromine resulted in more rehardening than F, however less than 2×F. F+theobromine was similar to F. For EFU, F+Sr was inferior to F, F+theobromine and F+Sr+theobromine which were similar and inferior to 2×F. In absence of fluoride, Sr, theobromine or Sr+theobromine were virtually indistinguishable from placebo and inferior to F. It can be concluded that a) strontium aids rehardening but not EFU and only in presence of fluoride; b) theobromine does not appear to offer any anti-caries benefits in this model; c) there are no synergistic effects between strontium and theobromine in the presence or absence of fluoride. Copyright © 2017 Elsevier Ltd. All rights reserved.

Production and use of carrier-free 18F in studies on the effect of trace amounts of fluoride on the metabolism of the oral cariogenic bacterium Streptococcus mutans

International Nuclear Information System (INIS)

Psarros, N.; Duschner, H.

1988-01-01

The utilization of carrier-free ionic 18 F is a convenient method for studying the effects of very low extracellular fluoride concentrations on the metabolism of the cariogenic bacterium Streptococcus mutans. A method was developed for the preparation of carrier-free aqueous solutions of ionic 18 F with high specific activity (about 70 7 Bq/ml). Fluoride distribution and fluoride binding experiments show that submicromolar fluoride concentrations had a negative effect on the metabolism of Streptococcus mutans. (author) 10 refs

Influence of Surfactants and Fluoride against Enamel Erosion.

Science.gov (United States)

Zanatta, Rayssa Ferreira; Ávila, Daniele Mara da Silva; Miyamoto, Karen Mayumi; Torres, Carlos Rocha Gomes; Borges, Alessandra Bühler

2018-06-06

This study investigated the effect of surfactants associated with sodium fluoride (NaF) on enamel erosion prevention, using an erosion-remineralization in vitro model. Sodium lauryl sulfate (SLS), polysorbate 20 (P20), and cocoamidopropyl betaine (CAPB) were tested, at concentrations of 1.0 and 1.5%, and associated or not with NaF (275 ppm). The control groups were distilled water and the NaF solution. Bovine enamel samples (n = 12) were prepared and submitted to a 5-day cycling model: acid challenge (0.3% citric acid, pH 2.6, 4×/day), human saliva (2 h, 4×/day), and the treatment solutions (2 min, 2×/day). The protective potential of the agents against initial erosion was assessed by microhardness and the surface loss by profilometry. Enamel surface wettability was determined by goniometry, protein adsorption was measured by spectroscopy (FTIR), and the KOH-soluble fluoride was quantified. Goniometry showed that SLS and CAPB increased enamel wettability. No differences were found among the surfactants regarding protein adsorption. Microhardness showed that SLS reduced NaF protection. P20 (1 and 1.5%) and CAPB 1.5% presented a protective effect, but lower than the NaF solution. Profilometry showed that CAPB protected enamel, but no agent associated with NaF promoted a higher protection than the NaF solution alone. KOH-soluble fluoride analysis showed that all surfactants reduced the fluoride adsorption on the enamel surface. Therefore, the surfactants tested (except for P20) changed the enamel surface energy. The SLS decreased the protective potential of NaF on initial erosion, but no tested agent interfered with the protective effect of NaF on enamel erosive wear. © 2018 S. Karger AG, Basel.

Preparation and characterization of poly(vinyl sulfone)- and poly(vinylidene fluoride)-based electrolytes

Energy Technology Data Exchange (ETDEWEB)

Choe, H.S.; Giaccai, J.; Alamgir, M.; Abraham, K.M. [EIC Labs., Inc., Norwood, MA (United States)

1995-10-01

A novel group of polymer electrolytes based on poly(vinyl sulfone) (PVS) and poly(vinylidene fluoride) (PVdF) polymers, plasticized with highly conductive solutions of LiClO{sub 4}, LiN(CF{sub 3}SO{sub 2}){sub 2} or LiAsF{sub 6} dissolved in ethylene carbonate, propylene carbonate, sulfolane, or mixtures thereof, was prepared via in situ photopolymerization and solution casting, respectively. The polymer electrolytes were characterized from conductivity and cyclic voltammetry data. It was found that solutions of Li salts in the vinyl sulfone monomer were highly conductive at room temperature with conductivities of 0.6 to 1.3 x 10{sup -3} {Omega}{sup -1}cm{sup -1} at 30{sup o}C, but the conductivities decreased by about 10{sup 3} times on polymerizing. Conversely, the conductivities increased by about 10{sup 2} to 10{sup 4} times on incorporating plasticizing solvents into the solid polymer electrolytes, suggesting that ionic mobility is the primary factor affecting the conductivities of solid polymer electrolytes. The highest conductivity exhibited by PVS-based electrolyte was 3.74 x 10{sup -4} {Omega}{sup -1}cm{sup -1} and that by PVdF-based electrolyte was 1.74 x 10{sup -3} {Omega}{sup -1}cm{sup -1}, at 30{sup o}C. The PVS-based electrolytes were found to be stable to oxidation up to potentials ranging between 4.5 and 4.8 V, while the stable potential limits for PVdF-based electrolytes were between 3.9 and 4.3 V vs. Li{sup +}/Li. (author)

Comparative Analysis of Fluoride Concentrations in Groundwaters in Northern and Southern Ghana: Implications for the Contaminant Sources

Science.gov (United States)

Sunkari, Emmanuel Daanoba; Zango, Musah Saeed; Korboe, Harriet Mateko

2018-04-01

Bongo and Sekyere South districts, both in the northern and southern parts of Ghana, respectively, have high populations living in rural areas and most of them use groundwater for drinking purposes. The groundwater in these areas is prone to contamination from natural and/or artificial sources. Therefore this study aims; (1) to present a comparative analysis of the fluoride concentration in groundwater samples from Bongo and Sekyere South districts and the associated groundwater-rock interaction that may be the cause for the varied fluoride concentrations, (2) to determine the leaching potential of fluoride from the host rocks as the possible mechanism for groundwater contamination. Sixty (60) groundwater samples from active pumping wells and twelve (12) rock samples from outcrops were collected from various communities in the two districts for fluoride concentration and mineralogical analysis. Based on the variations in fluoride concentration, fluoride spatial distribution maps were prepared using empirical Bayesian kriging interpolation method and analysed by means of hierarchical cluster analysis. The fluoride concentration in Bongo district varies between 1.71 and 4.0 mg/L, whereas that in Sekyere South district changes from 0.3 to 0.8 mg/L. From the mineralogical studies, biotite has the highest percentage in the Bongo district and has positive correlation with fluoride concentration in the analysed water samples than in the Sekyere South district. The elevated fluoride concentration in the Bongo district relative to the Sekyere South district is due to the dissolution of biotite in the groundwater and the sufficient groundwater-rock interaction since the water samples are mainly sourced from deeper boreholes. This high fluoride concentration has resulted in a plethora of reported cases of dental fluorosis and other health-related issues in Bongo.

A high resolution cross section transmission electron microscopy study of epitaxial rare earth fluoride/GaAs(111) interfaces prepared by molecular beam epitaxy

International Nuclear Information System (INIS)

Chien, C.J.; Bravman, J.C.

1990-01-01

The authors report the HRXTEM study of epitaxial rare earth fluoride/GaAs(111) interfaces. Such interfaces are of interest because they are the starting point for growth of buried epitaxial rare earth/rare earth fluoride sandwich structures which exhibit interesting and non bulk-like magnetic properties. Also, the optical transitions in ultrathin epitaxial NdF 3 films may be influenced by strain and defects in the NdF 3 film and the nature of the interface to GaAs. The authors find that the rare earth fluoride/GaAs interfaces are semi-coherent but chemically abrupt with the transition taking place within 3 Angstrom. However, the interface is physically rough and multiple monolayer steps in the GaAs surface tend to tilt boundaries in the fluoride. The origin of these steps is believed to be thermal etching of the GaAs during the heat- cleaning stage prior to epitaxy. The surface of the fluoride film is much smoother than the initial GaAs surface indicating planarization during epitaxy

A review of slow-release fluoride devices.

Science.gov (United States)

Toumba, K J; Al-Ibrahim, N S; Curzon, M E J

2009-09-01

Fluoride has been used to combat dental caries using a number of different clinical approaches. An exciting relatively new development is fluoride slow-releasing devices that consistently elevate intra-oral fluoride levels of plaque and saliva for prolonged periods of up to two years. The literature on the use of slow-releasing fluoride devices in dentistry were reviewed. A Medline search on key words was carried out. All papers in English were individually reviewed. Slow-releasing fluoride devices have been shown to be effective in elevating salivary fluoride levels in both animals and human studies and to enhance the remineralisation of dental enamel. They have been demonstrated to be safe to use and without the risk of fluoride toxicity. A double blind randomised clinical trial demonstrated 76% fewer new carious surface increment in high caries-risk children after two years. These devices have a number of potential uses in dentistry and in particular have great potential for caries prevention of non-compliant high caries-risk groups.

Effects of fluoridated milk on root dentin remineralization.

Directory of Open Access Journals (Sweden)

Wolfgang H Arnold

Full Text Available The prevalence of root caries is increasing with greater life expectancy and number of retained teeth. Therefore, new preventive strategies should be developed to reduce the prevalence of root caries. The aim of this study was to investigate the effects of fluoridated milk on the remineralization of root dentin and to compare these effects to those of sodium fluoride (NaF application without milk.Thirty extracted human molars were divided into 6 groups, and the root cementum was removed from each tooth. The dentin surface was demineralized and then incubated with one of the following six solutions: Sodium chloride NaCl, artificial saliva, milk, milk+2.5 ppm fluoride, milk+10 ppm fluoride and artificial saliva+10 ppm fluoride. Serial sections were cut through the lesions and investigated with polarized light microscopy and quantitative morphometry, scanning electron microscopy (SEM and energy-dispersive X-ray spectroscopy (EDS. The data were statistically evaluated using a one-way ANOVA for multiple comparisons.The depth of the lesion decreased with increasing fluoride concentration and was the smallest after incubation with artificial saliva+10 ppm fluoride. SEM analysis revealed a clearly demarcated superficial remineralized zone after incubation with milk+2.5 ppm fluoride, milk+10 ppm fluoride and artificial saliva+10 ppm fluoride. Ca content in this zone increased with increasing fluoride content and was highest after artificial saliva+10 ppm fluoride incubation. In the artificial saliva+10 ppm fluoride group, an additional crystalline layer was present on top of the lesion that contained elevated levels of F and Ca.Incubation of root dentin with fluoridated milk showed a clear effect on root dentin remineralization, and incubation with NaF dissolved in artificial saliva demonstrated a stronger effect.

Estimation of atmospheric fluoride by limed filter papers

International Nuclear Information System (INIS)

Smith, D.R.

1988-09-01

The limed filter paper method of static sampling of atmospheric fluoride is reviewed in this report. Use of the technique, in conjunction with precise measurement of the absorbed fluoride and calibration with dynamic air sampling techniques, to estimate atmospheric fluoride levels, is considered to give only qualitative data (± 50%). The limed filter paper method is site specific due to variations in meteorological conditions. Its main value is to indicate seasonal and annual trends in fluoride exposure of vegetation. Subject to these considerations, the lower and upper limits of atmospheric fluoride exposure and the applicability to atmospheric fluoride estimation under routine or emergency fluoride release conditions are discussed, with special emphasis on the limiting factors

[The effects of topical fluoridation of Ketac Molar Aplicap glass-ionomer material on the growth of cariogenic bacteria contained in the dental plaque].

Science.gov (United States)

Płuciennik-Stronias, Małgorzata; Zarzycka, Beata; Bołtacz-Rzepkowska, Elzbieta

2013-01-01

Dental caries is a bacterial disease. The most important element used in caries prevention is fluoride, which is derived from the air, diet or fluoride-containing preparations and materials, e.g. glass-ionomer restorations. Modern fluoride-containing restorative materials are capable of releasing fluoride to the environment. Fluoride can be also accumulated in glass-ionomer cements, thus an attempt was made to saturate these materials with fluoride. The aim of the study was to evaluate the effect of topical fluoridation of Ketac Molar Aplicap glass-ionomer cement on the growth of Lactobacillus spp. in the dental plaque. The study was carried out in 15 patients with good oral hygiene, in whom 35 fillings with conventional glass-ionomer material, Ketac Molar Aplicap, were performed. After 6 months, three-day dental plaque from these fillings was examined. Next, fluoride was rubbed on the glass-ionomer surface and the examination of three-day dental plaque was repeated. No statistically significant differences (p = 0.143) in the amounts of Lactobacillus spp. in the plaque collected prior to and after topical fluoridation were revealed. Fluoride rubbed in the conventional glass-ionomer cement, Ketac Molar Aplicap, did not affect the amount of Lactobacillus spp. in the dental plaque growing on this material.

Scandium fluorides

International Nuclear Information System (INIS)

Melnikov, P.; Nalin, M.; Messaddeq, Y.

1997-01-01

A new modification of scandium fluoride has been synthesised. The compound is deficient in fluorine, with the composition ScF 2.76 . It belongs to the tetragonal system, lattice parameters being a=3.792 and c=6.740 A and may be obtained at low temperatures by the decomposition of the precursor NH 4 ScF 4 . The reaction is topotactic, tetragonal parameters of the precursor are a=4.021 and c=6.744 A. Structural relationships with various fluorides and ammonium aminofluorides are discussed. This synthesis route with IR-assisted decomposition should be considered as a soft-chemistry approach. (orig.)

Preparation and self-assembly of amphiphilic polylysine dendrons

DEFF Research Database (Denmark)

Mirsharghi, Sahar; Knudsen, Kenneth D.; Bagherifam, Shahla

2016-01-01

Polylysine dendrons with lipid tails prepared by divergent solid-phase synthesis showed self-assembling properties in aqueous solutions., Herein, we present the synthesis of new amphiphilic polylysine dendrons with variable alkyl chain lengths (C1–C18) at the C-terminal. The dendrons were...... synthesized in moderate to quantitative yields by divergent solid-phase synthesis (SPS) employing an aldehyde linker. The self-assembling properties of the dendrons in aqueous solutions were studied by small angle neutron scattering (SANS) and dynamic light scattering (DLS). The self-assembling properties...... were influenced by the length of the alkyl chain and the generation number (Gn). Increasing the temperature and concentration did not have significant impact on the hydrodynamic diameter, but the self-assembling properties were influenced by the pH value. This demonstrated the need for positively...

Comparison of La3+ and mixed rare earths-loaded magnetic chitosan beads for fluoride adsorption

DEFF Research Database (Denmark)

Liang, Peng; An, Ruiqi; Li, Ruifen

2018-01-01

La3+ and mixed-rare earth magnetic chitosan beads (MCLB and MCLRB) were successfully prepared for fluoride removal, respectively. The adsorbents were characterized by scanning electron microscope and magnetic response. Batch experiments were carried out to investigate the adsorbent performance...

Atmospheric fluoride levels in some Ontario peach orchards

Energy Technology Data Exchange (ETDEWEB)

Drowley, W B; Rayner, A C; Jephcott, C M

1963-10-01

As a result of suture injury to peaches, a survey was taken to determine monthly atmospheric fluoride levels in the soft fruit-growing area of the Niagara Peninsula of Ontario. Although the injury was confined to a few orchards, it was found necessary to locate stations for fluoride sampling over a wide area. The limed-paper candle method was used for fluoride collection. Unwashed and washed peach leaves were analyzed for fluoride content. Fluoride was separated from all samples by the Willard-Winter distillation procedure and estimated colorimetrically. It was found that a general background level of atmospheric fluoride existed in the whole surveyed area and that the levels were highest in and near the area of peach injury. The fluoride content of peach leaves was also highest in this area. The coincidence of high fluoride levels and suture injury to peaches suggests that atmospheric fluoride was the causal agent. When lime sprays were applied to peach trees in the damaged area, a reduction in the incidence of suture injury was observed.

Preparation and evaluation of nattokinase-loaded self-double-emulsifying drug delivery system

OpenAIRE

Wang, Xiaona; Jiang, Sifan; Wang, Xinyue; Liao, Jie; Yin, Zongning

2015-01-01

In the present study, we prepared nattokinase-loaded self-double-emulsifying drug delivery system (SDEDDS) and investigated its preliminary pharmacodynamics. The type and concentration of oil phase, inner aqueous phase and emulsifier were screened to prepare optimum nattokinase-loaded SDEDDS. Next, the optimum formulations were characterized based on microstructure, volume-weighted mean droplet size, self-emulsifying rate, yield, storage stability, in vitro release and in vivo pharmacodynamic...

Adverse effects of fluoride towards thyroid hormone metabolism

Directory of Open Access Journals (Sweden)

Enggar Abdullah Idris MZ

2008-03-01

Full Text Available An easily ionized fluoride compound like Sodium Fluoride (NaF has been used thus far as a dental caries prevention substance. However, fluoride ions also have a negative effect because it is very toxic. Several types of research on the effect of fluoride on guinea pigs and human beings indicate the presence synthesis obstruction of T3 and T4 that causes declined production, known as hypothyroidism. Hypothyroidism condition may obstruct tissue growth process and metabolism so as to impact various body organ systems. Preventive efforts against hypothyroidism caused by fluoride include avoiding diffusible fluoride compound intake, like NaF, in a long run systemic use, whereas efforts to overcome fluoride intoxication include consuming food that is rich in calcium, vitamin D, and antioxidant.

Fluoride and Water (For Parents)

Science.gov (United States)

... risk of tooth decay" on the label. The Controversy Over Fluoride Opponents of water fluoridation have questioned ... Us Contact Us Partners Editorial Policy Permissions Guidelines Privacy Policy & Terms of Use Notice of Nondiscrimination Visit ...

Physiologic Conditions Affect Toxicity of Ingested Industrial Fluoride

OpenAIRE

Richard Sauerheber

2013-01-01

The effects of calcium ion and broad pH ranges on free fluoride ion aqueous concentrations were measured directly and computed theoretically. Solubility calculations indicate that blood fluoride concentrations that occur in lethal poisonings would decrease calcium below prevailing levels. Acute lethal poisoning and also many of the chronic effects of fluoride involve alterations in the chemical activity of calcium by the fluoride ion. Natural calcium fluoride with low solubility and toxicity ...

Fluoride Removal from Water by Reverse Osmosis Membrane

Directory of Open Access Journals (Sweden)

Sara Namavar

2013-09-01

Full Text Available As fluoride concentration in drinking water is one of the effective parameters in human health, finding the way to remove excess amount of fluoride from drinking water is very important in water supply projects. Today, with developing in technology and finding new methods, the use of membrane technology for producing fresh water get improved. In this study the efficiency of reverse osmosis method to remove fluoride from water was investigated. Initial concentration of fluoride, sulfate and electrical conductivity in feed water and the effect of associated cation with fluoride ion were studied. All tests adapted from “Standard Methods for Examination of Water and Wastewater”. Determination of fluoride concentration was done according the standard SPANDS method by using a spectrophotometer DR/5000. Obtain results show that with increasing in concentration of fluoride and sulfate and electrical conductivity in feed water the efficiency of RO membrane to remove fluoride reduced. In addition, this efficiency for CaF2 was higher than NaF.

Effect of Fluoride-Releasing Adhesive Systems on the Mechanical Properties of Eroded Dentin.

Science.gov (United States)

Guedes, Ana Paula Albuquerque; Moda, Mariana Dias; Suzuki, Thaís Yumi Umeda; Godas, André Gustavo de Lima; Sundfeld, Renato Herman; Briso, André Luiz Fraga; Santos, Paulo Henrique dos

2016-01-01

The aim of the study was to evaluate the effect of erosive pH cycling with solutions that simulate dental erosion on Martens hardness (HMV) and elastic modulus (Eit) of dentin restored with fluoride-releasing adhesive systems. Twenty-seven bovine dentin slabs were restored with three adhesive systems: Adper Single Bond 2 total-etch adhesive system, One Up Bond F and Clearfil SE Protect fluoride-containing self-etching adhesive systems. The restorations were made with Filtek Z250. The HMV and Eit values at distances of 10, 30, 50 and 70 µm from the interface were evaluated using a dynamic ultra microhardness tester before and after immersion in deionized water, citric acid and hydrochloric acid (n=9). Data were submitted to repeated-measures ANOVA and Fisher's PLSD tests (=0.05). After erosive cycling, HMV values of dentin decreased in all groups. For dentin restored with Adper Single Bond 2, the lowest values were found closer to the hybrid layer, while for One Up Bond F and Clearfil SE Protect, the values remained unaltered at all distances. For dentin restored with fluoride-releasing adhesive systems, a decrease in Eit was found, but after 30 µm this difference was not significant. The acid substances were able to alter HMV and Eit of the underlying dentin. For fluoride-releasing adhesives, the greater the distance from bonded interface, the lower the Eit values. The fluoride in One Up Bond F and Clearfil SE Protect was able to protect the underlying dentin closer to the materials. In this way, the fluoride from adhesive systems could have some positive effect in the early stages of erosive lesions.

Impact of Dental Fluorosis, Socioeconomic Status and Self-Perception in Adolescents Exposed to a High Level of Fluoride in Water

Science.gov (United States)

Molina-Frechero, Nelly; Nevarez-Rascón, Martina; Nevarez-Rascón, Alfredo; González-González, Rogelio; Irigoyen-Camacho, María Esther; Sánchez-Pérez, Leonor; López-Verdin, Sandra; Bologna-Molina, Ronell

2017-01-01

Objective: To identify adolescents’ self-perception of dental fluorosis from two areas with different socioeconomic levels. Methods: A cross-sectional, descriptive study was conducted with 15-year-old youths by applying a questionnaire designed and validated to assess self-perceptions of dental fluorosis in two areas with different socioeconomic statuses (SESs). Fluorosis was clinically evaluated by applying the Thylstrup and Fejerkov (TF) index on the upper front teeth. Results: A total of 308 adolescents were included in the study. The medium-SES population, which was exposed to 2.5 ppm of fluoride in water, and the low-SES population, which was exposed to 5.1 ppm, presented the following levels of dental fluorosis: TF 2–3 (50%), TF 4–5 (45.6%) and TF 6–7 (4.4%) for medium SES and TF 2–3 (12.3%), TF 4–5 (67.1%) and TF 67 (20.6%) for low SES. A significant association was found between self-perception and dental fluorosis in those with medium and low SESs (p < 0.05). The multiple regression model found differences between TF levels and self-perception, with a 6–7 TF level for concerns about color (OR = 1.6), smile (OR = 1.2) and appearance (OR = 3.36). Conclusions: Self-perceptions of dental fluorosis affect adolescents such that adolescents with a medium SES have more negative perceptions than those with a low SES. Such perceptions increase as the TF index increases. PMID:28085102

Impact of Dental Fluorosis, Socioeconomic Status and Self-Perception in Adolescents Exposed to a High Level of Fluoride in Water

Directory of Open Access Journals (Sweden)

Nelly Molina-Frechero

2017-01-01

Full Text Available Objective: To identify adolescents’ self-perception of dental fluorosis from two areas with different socioeconomic levels. Methods: A cross-sectional, descriptive study was conducted with 15-year-old youths by applying a questionnaire designed and validated to assess self-perceptions of dental fluorosis in two areas with different socioeconomic statuses (SESs. Fluorosis was clinically evaluated by applying the Thylstrup and Fejerkov (TF index on the upper front teeth. Results: A total of 308 adolescents were included in the study. The medium-SES population, which was exposed to 2.5 ppm of fluoride in water, and the low-SES population, which was exposed to 5.1 ppm, presented the following levels of dental fluorosis: TF 2–3 (50%, TF 4–5 (45.6% and TF 6–7 (4.4% for medium SES and TF 2–3 (12.3%, TF 4–5 (67.1% and TF 67 (20.6% for low SES. A significant association was found between self-perception and dental fluorosis in those with medium and low SESs (p < 0.05. The multiple regression model found differences between TF levels and self-perception, with a 6–7 TF level for concerns about color (OR = 1.6, smile (OR = 1.2 and appearance (OR = 3.36. Conclusions: Self-perceptions of dental fluorosis affect adolescents such that adolescents with a medium SES have more negative perceptions than those with a low SES. Such perceptions increase as the TF index increases.

FLUORIDE: A REVIEW OF USE AND EFFECTS ON HEALTH.

Science.gov (United States)

Kanduti, Domen; Sterbenk, Petra; Artnik, Barbara

2016-04-01

Appropriate oral health care is fundamental for any individual's health. Dental caries is still one of the major public health problems. The most effective way of caries prevention is the use of fluoride. The aim of our research was to review the literature about fluoride toxicity and to inform physicians, dentists and public health specialists whether fluoride use is expedient and safe. Data we used in our review were systematically searched and collected from web pages and documents published from different international institutions. Fluoride occurs naturally in our environment but we consume it in small amounts. Exposure can occur through dietary intake, respiration and fluoride supplements. The most important factor for fluoride presence in alimentation is fluoridated water. Methods, which led to greater fluoride exposure and lowered caries prevalence, are considered to be one of the greatest accomplishments in the 20th century`s public dental health. During pregnancy, the placenta acts as a barrier. The fluoride, therefore, crosses the placenta in low concentrations. Fluoride can be transmitted through the plasma into the mother's milk; however, the concentration is low. The most important action of fluoride is topical, when it is present in the saliva in the appropriate concentration. The most important effect of fluoride on caries incidence is through its role in the process of remineralization and demineralization of tooth enamel. Acute toxicity can occur after ingesting one or more doses of fluoride over a short time period which then leads to poisoning. Today, poisoning is mainly due to unsupervised ingestion of products for dental and oral hygiene and over-fluoridated water. Even though fluoride can be toxic in extremely high concentrations, it`s topical use is safe. The European Academy of Paediatric Dentistry (EAPD) recommends a preventive topical use of fluoride supplements because of their cariostatic effect.

Strontium-90 fluoride data sheet

Energy Technology Data Exchange (ETDEWEB)

Fullam, H.T.

1981-06-01

This report is a compilation of available data and appropriate literature references on the properties of strontium-90 fluoride and nonradioactive strontium fluoride. The objective of the document is to compile in a single source pertinent data to assist potential users in the development, licensing, and use of /sup 90/SrF/sub 2/-fueled radioisotope heat sources for terrestrial power conversion and thermal applications. The report is an update of the Strontium-90 Fluoride Data Sheet (BNWL-2284) originally issued in April 1977.

Evaluation and Assessment of Fluoride in Drinking Water Wells Damavand Villages Zoning in GIS According to DMF Index

OpenAIRE

Kave Kheirkhah Rahimabad; Amir Hessam Hasani; Reza Saeedi; Mir Masoud Kheirkhah Zarkesh; Mojtaba Sayadi

2016-01-01

Background:Fluoride is one the vital anions and the drinking water is the main source of preparing it for the human body. Nonetheless, the aim of this paper is to investigate the Fluoride rate in water supplying wells by using GIS environment according to decay, missing or filled (DMF) index.  Methods: This research is an analytic and cross-sectional descriptive study with sampling approach of 12 water supplying wells of Damavand villages in summer and autumn the year 2013. The Fluor...

Potential fluoride toxicity from oral medicaments: A review

OpenAIRE

Rizwan Ullah; Muhammad Sohail Zafar; Nazish Shahani

2017-01-01

The beneficial effects of fluoride on human oral health are well studied. There are numerous studies demonstrating that a small amount of fluoride delivered to the oral cavity decreases the prevalence of dental decay and results in stronger teeth and bones. However, ingestion of fluoride more than the recommended limit leads to toxicity and adverse effects. In order to update our understanding of fluoride and its potential toxicity, we have described the mechanisms of fluoride metabolism, tox...

Low-levels of fluoride in plaque and saliva and their effects on the demineralisation and remineralisation of enamel; role of fluoride toothpastes.

Science.gov (United States)

Lynch, R J M; Navada, R; Walia, R

2004-01-01

To summarise support for current consensus on the likely means by which fluoride toothpastes reduce caries and review some relevant studies of the effect of low levels of fluoride on the demineralisation and remineralisation of enamel. The major anti-caries effect of fluoride toothpastes is thought to result from small but protracted elevations in levels of fluoride in plaque and saliva. Fluoride incorporated into enamel systemically does not reduce enamel solubility sufficiently to exert an anti-caries effect. Fluoride has the potential to exert an anti-caries benefit largely through three mechanisms; inhibition of demineralisation, promotion of remineralisation and interference with bacterial growth and metabolism. However, the low levels of fluoride thought to influence caries are insufficient to have a significant effect via the latter mechanism. Thus reductions in caries resulting from the use of fluoride toothpastes can be linked to modification of the demineralisation/remineralisation balance by direct effects on dental mineral exerted topically by low levels of fluoride. Numerous in vitro studies have shown that low levels of fluoride, typical of those found after many hours in resting plaque and saliva, and resulting from the regular use of fluoride toothpastes, can have a profound effect on enamel demineralisation and remineralisation.

Reuse of ammonium fluoride generated in the uranium hexafluoride conversion

International Nuclear Information System (INIS)

Silva Neto, J.B.; Carvalho, E.F. Urano de; Durazzo, M.; Riella, H.G

2010-01-01

The Nuclear Fuel Centre of IPEN / CNEN - SP develops and manufactures dispersion fuel with high uranium concentration to meet the demand of the IEA-R1 reactor and future research reactors planned to be constructed in Brazil. The fuel uses uranium silicide (U 3 Si 2 ) dispersed in aluminum. For producing the fuel, the processes for uranium hexafluoride (UF 6 ) conversion consist in obtaining U 3 Si 2 and / or U 3 O 8 through the preparation of intermediate compounds, among them ammonium uranyl carbonate - AUC, ammonium diuranate - DUA and uranium tetrafluoride - UF 4 . This work describes a procedure for preparing uranium tetrafluoride by a dry route using as raw material the filtrate generated when producing routinely ammonium uranyl carbonate. The filtrate consists primarily of a solution containing high concentrations of ammonium (NH 4 + ), fluoride (F - ), carbonate (CO 3 -- ) and low concentrations of uranium. The procedure is basically the recovery of NH 4 F and uranium, as UF 4 , through the crystallization of ammonium bifluoride (NH 4 HF 2 ) and, in a later step, the addition of UO 2 , occurring fluoridation and decomposition. The UF 4 obtained is further diluted in the UF 4 produced routinely at IPEN / CNEN-SP by a wet route process. (author)

Preparation of microporous Cellulose/Poly(vinylidene fluoride-hexafluoropropylene) membrane for lithium ion batteries by phase inversion method

Science.gov (United States)

Asghar, Muhammad Rehman; Zhang, Yao; Wu, Aiming; Yan, Xiaohui; Shen, Shuiyun; Ke, Changchun; Zhang, Junliang

2018-03-01

In this work, a porous and honeycomb-structured Cellulose/Poly (vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) membrane is prepared via a facile and ecofriendly phase inversion method by using glycerol as pore forming agent. Cellulose acetate, the source of cellulose, is easily converted into cellulose by hydrolysis in the presence of lithium hydroxide. Owing to the unique microstructure, the Cellulose/PVDF-HFP membrane offers several advantages, including high porosity, elevated electrolyte uptake, high ion conductivity, and wide electrochemical window (5.35 V). Compared with conventional polypropylene (PP) separator and PVDF-HFP membrane, the membrane developed in this work enables higher discharge capacity, higher lithium-ion transference number (0.89) and improved rate performance, which is able to maintain a high discharge capacity of 136 mAh g-1 at 8 C, using LiCoO2 as cathode and Li metal as anode. In addition, the Cellulose/PVDF-HFP membrane based batteries exhibit superior cycling performance that can maintain 91.7% capacity after 100 cycles at 0.2 C. The characterization and battery test results demonstrate that the membrane is highly compatible with lithium ion batteries.

Fluoride release and cariostatic potential of orthodontic adhesives with and without daily fluoride rinsing.

NARCIS (Netherlands)

Chin, M.Y.; Sandham, A.; Rumachik, E.N.; Ruben, J.L.; Huysmans, M.C.D.N.J.M.

2009-01-01

INTRODUCTION: In this study, we aimed to evaluate the fluoride-release profiles and caries lesion development in an enamel model with brackets cemented with 4 orthodontic adhesives with and without daily fluoride exposure. METHODS: Four orthodontic adhesives (Ketac Cem mu, 3M ESPE, Seefeld, Germany;

Fluoride release and cariostatic potential of orthodontic adhesives with and without daily fluoride rinsing

NARCIS (Netherlands)

Chin, Yeen; Sandham, John; Rumachik, Elena N.; Ruben, Jan L.; Huysmans, Marie-Charlotte D. N. J. M.

2009-01-01

Introduction: In this study, we aimed to evaluate the fluoride-release profiles and caries lesion development in an enamel model with brackets cemented with 4 orthodontic adhesives with and without daily fluoride exposure. Methods: Four orthodontic adhesives (Ketac Cem mu, 3M ESPE, Seefeld, Germany;

Self-directed Learning in Otolaryngology Residents' Preparation for Surgical Cases.

Science.gov (United States)

Jabbour, Jad; Bakeman, Anna; Robey, Thomas; Jabbour, Noel

2017-04-01

To characterize the nature of surgical preparation among otolaryngology residents nationwide, determine the self-rated effectiveness and efficiency of case preparation practices, and identify potential means for educational improvement. A survey examining the study objectives was developed and distributed to otolaryngology residents nationwide. Survey response data were submitted to descriptive analysis and comparative analyses between junior and senior residents. Literature regarding case preparation among otolaryngology residents was reviewed. Among 108 resident respondents, the most commonly used resources included textbooks (86.1%), surgical education websites (74.1%), and surgical atlases (66.7%). Time was the primary limitation (cited by 84.3%) and convenience the predominant factor influencing resource selection (92.5%). On a 5-point Likert scale, mean scores regarding effectiveness and efficiency of case preparation were 3.53 ± 0.68 and 3.19 ± 0.88, respectively. Senior residents compared to junior residents were more likely to rate their preparation as effective (3.75 ± 0.54 vs 3.40 ± 0.72, P = .008) and efficient (3.45 ± 0.85 vs 3.03 ± 0.86, P = .02). Otolaryngology residents do not consistently rate their case preparation as effective or efficient. While there appears to be progress in self-directed learning throughout residency, room for improvement remains, with potential avenues for such improvement explored here.

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

Science.gov (United States)

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.

Acute toxicity of ingested fluoride.

Science.gov (United States)

Whitford, Gary Milton

2011-01-01

This chapter discusses the characteristics and treatment of acute fluoride toxicity as well as the most common sources of overexposure, the doses that cause acute toxicity, and factors that can influence the clinical outcome. Cases of serious systemic toxicity and fatalities due to acute exposures are now rare, but overexposures causing toxic signs and symptoms are not. The clinical course of systemic toxicity from ingested fluoride begins with gastric signs and symptoms, and can develop with alarming rapidity. Treatment involves minimizing absorption by administering a solution containing calcium, monitoring and managing plasma calcium and potassium concentrations, acid-base status, and supporting vital functions. Approximately 30,000 calls to US poison control centers concerning acute exposures in children are made each year, most of which involve temporary gastrointestinal effects, but others require medical treatment. The most common sources of acute overexposures today are dental products - particularly dentifrices because of their relatively high fluoride concentrations, pleasant flavors, and their presence in non-secure locations in most homes. For example, ingestion of only 1.8 ounces of a standard fluoridated dentifrice (900-1,100 mg/kg) by a 10-kg child delivers enough fluoride to reach the 'probably toxic dose' (5 mg/kg body weight). Factors that may influence the clinical course of an overexposure include the chemical compound (e.g. NaF, MFP, etc.), the age and acid-base status of the individual, and the elapsed time between exposure and the initiation of treatment. While fluoride has well-established beneficial dental effects and cases of serious toxicity are now rare, the potential for toxicity requires that fluoride-containing materials be handled and stored with the respect they deserve. Copyright © 2011 S. Karger AG, Basel.

Inhibition of cellular oxidation by fluoride

Energy Technology Data Exchange (ETDEWEB)

Borei, H

1945-01-01

An attempt has been made to investigate the inhibition by fluoride of the oxidative processes which occur in the cell by way of the cytochrome oxidase-cytochrome system. Some chemical and physical properties of the fluoride ion are discussed, together with certain quantitative methods for the determination of fluoride. An exhaustive review of the literature concerning the effect of fluoride on enzymic processes has been compiled. The experiments have shown that the point of the attack by fluoride is to be found among the cytochromes. The inhibitory mechanism appears to be such that the haemoprotein is prevented from taking part in the preceding and succeeding links in the reaction chain. The blocking action leaves the prosthetic group of the haemoprotein completely unchanged. The experimental results indicate the formation of a fluorophosphoprotein complex, analogous to that found in the case of enolase. Magnesium may possibly play a part in this process.

Acute toxicity of uranium hexafluoride, uranyl fluoride and hydrogen fluoride

International Nuclear Information System (INIS)

Just, R.A.

1988-01-01

Uranium hexafluoride (UF 6 ) released into the atmosphere will react rapidly with moisture in the air to form the hydrolysis products uranyl fluoride (UO 2 F 2 ) and hydrogen fluoride (HF). Uranium compounds such as UF 6 and UO 2 F 2 exhibit both chemical toxicity and radiological effects, while HF exhibits only chemical toxicity. This paper describes the development of a methodology for assessing the human health consequences of a known acute exposure to a mixture of UF 6 , UO 2 F 2 , and HF. 4 refs., 2 figs., 5 tabs

Evaluation of toxic action of fluorides on agricultural plants

Directory of Open Access Journals (Sweden)

V. N. Grishko

2007-03-01

Full Text Available The toxicity of potassium fluoride, sodium fluoride and ammonium fluoride for pea, maize, oat and onion was studied. It was found that the level of the toxic influence had grown with increase of fluoride concentration in the media of growth (from 5 to 100 mg of F–/l. By increase of the toxic influence the agricultural crops are disposed in the following row: oat < onion < maize < pea. Ammonium fluoride demonstrates lesser toxicity, than potassium and sodium fluorides. Under low concentrations of fluoride compounds (5 and 10 mg of F–/l stimulation of roots growth is noted only for the oat.

Preparation and physical characteristics of a lithium-beryllium-substituted fluorapatite

International Nuclear Information System (INIS)

Lexa, D.

1999-01-01

A lithium-beryllium-substituted fluorapatite, Li 0.50 Be 0.25 Ca 4.50 (PO 4 ) 3 F, has been prepared by means of a high-temperature reaction between lithium beryllium fluoride, Li 2 BeF 4 , and tricalcium phosphate, Ca 3 (PO 4 ) 2 . This material has potential application as a waste form for radioactive and toxic fluoride salts. Monitoring of the reaction progress by differential scanning calorimetry indicated that the reaction was initiated by melting of the fluoride salt and that it was fast and complete. While reactive sintering of lithium beryllium fluoride with tricalcium phosphate led to a rather porous product, melting of the reactants with subsequent solidification readily produced a substituted fluorapatite with a near-theoretical bulk density

ODS - modified TiO2 nanoparticles for the preparation of self-cleaning superhydrophobic coating

Science.gov (United States)

Kokare, Ashvini M.; Sutar, Rajaram S.; Deshmukh, S. G.; Xing, Ruimin; Liu, Shanhu; Latthe, Sanjay S.

2018-05-01

Rolling water drops takes off dust particles from lotus leaf showing self-cleaning performance. Self-cleaning effect has great importance in industry as well as in daily life. The present paper describes the preparation of self-cleaning superhydrophobic coating through simple and low cost dip coating technique. The prepared superhydrophobic surface enact as lotus leaf. Firstly TiO2 nanoparticles were dispersed in ethanol and different concentration of octadecyltrichlorosilane (ODS) was added in TiO2 dispersion. The effect of number of deposition layer on the wettability of the coating was studied. The coating prepared from five deposition layers showed contact angle higher than 150° and sliding angle less than 10°. The superhydrophobicity increases with increasing concentration of ODS. The hierarchical rough morphology which is preferable for superhydrophobicity was obtained. The prepared coatings were stable against water jet impact and showed repellent towards colored and muddy water. Such superhydrophobic coating can find enormous scope in self-cleaning application.

Dry uranium tetrafluoride process preparation using the uranium hexafluoride reconversion process effluents

International Nuclear Information System (INIS)

Silva Neto, Joao Batista da

2008-01-01

It is a well known fact that the use of uranium tetrafluoride allows flexibility in the production of uranium suicide and uranium oxide fuel. To its obtention there are two conventional routes, the one which reduces uranium from the UF 6 hydrolysis solution with stannous chloride, and the hydro fluorination of a solid uranium dioxide. In this work we are introducing a third and a dry way route, mainly utilized to the recovery of uranium from the liquid effluents generated in the uranium hexafluoride reconversion process, at IPEN/CNEN-SP. Working in the liquid phase, this route comprises the recuperation of ammonium fluoride by NH 4 HF 2 precipitation. Working with the solid residues, the crystallized bifluoride is added to the solid UO 2 , which comes from the U mini plates recovery, also to its conversion in a solid state reaction, to obtain UF 4 . That returns to the process of metallic uranium production unity to the U 3 Si 2 obtention. This fuel is considered in IPEN CNEN/SP as the high density fuel phase for IEA-R1m reactor, which will replace the former low density U 3 Si 2 -Al fuel. (author)

Determination of Fluoride in Different Toothpaste Formulations

International Nuclear Information System (INIS)

Kamau, N.G.; Njoroge, M.; Njau, M.

1998-01-01

Fluoride ion selective electrode was used to determine fluoride ion concentrations in seven brands of toothpaste. These were the only available formulations found in Kenya. The brands were classified into three groups-fluoridated, non fluoridated or not indicated. However, there was no independent indication of their quantitative composition. The analysed brands had fluoride content between 0.0033% and 0.096%. These values compared favourably with those obtained elsewhere. The calculated lowest limit of detection (LLD) was 0.01 ppmF- . The mean calibration curve gave a slope of of -50.0mV. which was not significantly different from the theoretical value of 5.88mV at 23 degrees celsius at 95% confidence level

Anhydrous hydrogen fluoride electrolyte battery. [Patent application

Science.gov (United States)

Not Available

1972-06-26

It is an object of the invention to provide a primary cell or battery using ammonium fluoride--anhydrous hydrogen fluoride electrolyte having improved current and power production capabilities at low temperatures. It is operable at temperatures substantially above the boiling point of hydrogen fluoride. (GRA)

Fluoride ions vs removal technologies: A study

Directory of Open Access Journals (Sweden)

Jagvir Singh

2016-11-01

Full Text Available Literature reported that drinking water is a precious and scarce resource and it has to be protected and kept free from any kind of contamination. Further, it has to be used carefully without wasting. Literature also reported that fluoride bearing rocks are abundant in India, as a result, fluoride leaches out and contaminates the adjacent water and soil resources. A high concentration of fluoride ions in ground water increases up to more than 30 mg/L. This high concentration of fluoride ions causes many harmful and dangerous effects on our datum. Fluoride ions in larger quantities i.e. 20–80 mg/day taken over a period of 10–20 years result in crippling and skeletal fluorosis, severely damaging the bone. In the present scenario, there is a continuously increasing worldwide concern for the development of fluoride treatment technologies. Possibilities of reducing the high fluorine content in groundwater are by defluorination process/dilution with the surface water which is a very simple technique but the addition of Ca2+ ions to a solution in contact with fluorite when experimented in distilled water caused an appreciable decrease in fluoride concentration. In this review article, we emphasized the relationship between high concentrations of fluoride ions and their compounds and their health impact.

Spectrophotometric determination of Sn+2 in lyophilized kit for labeling with 99mTc

International Nuclear Information System (INIS)

Araujo, Elaine Bortoleti; Sampel, Carolina Judith; Melo, Ivani Bortoleti; Okamoto, Miriam R.Y; Silva, Constancia P.G

2004-01-01

The preparation of 99 mTc labeled radiopharmaceuticals depends on the reduction of the technetium pertechnetate, commonly by stannous chloride (SnCl 2 ). The determination of the Sn +2 contents in the lyophilized preparations represents an important quality control procedure that may be applied to the process and to the final product. The objective os this work is the optimization of an spectrophotometric assay to the determination os Sn +2 contents in a citrate-stannous lyophilized kit for 99 mTc labeling. The spectrophotometric methodology employed is based in the colour development when Sn +2 reacts with sodium molybdate in the presence of potasium thiocyanate in chloridric medium. The colourfull reaction studied showed high stability after 60 minutes of the mixtures preparation. The sequence of reagents introduction in the reaction mixture was determinant to the assay. The molibdenium-stannous-tiocianate sequence produces calibration curves with good correlations (R2 ≥ 0.99). The concentrations of the molibdenium solution was also studied, in order to determine a ideal concentration for the Sn +2 range. The spectrophotometric method studied was usefull to the determination of Sn +2 content in different batches of citrate-stannous preparations. The method was fast and easy and can be applied to different stages of the production process, in order to guarantee the content of Sn +2 in the preparations (Au)

Risk Assessment of Fluoride Intake from Tea in the Republic of Ireland and its Implications for Public Health and Water Fluoridation

Science.gov (United States)

Waugh, Declan T.; Potter, William; Limeback, Hardy; Godfrey, Michael

2016-01-01

The Republic of Ireland (RoI) is the only European Country with a mandatory national legislation requiring artificial fluoridation of drinking water and has the highest per capita consumption of black tea in the world. Tea is a hyperaccumulator of fluoride and chronic fluoride intake is associated with multiple negative health outcomes. In this study, fifty four brands of the commercially available black tea bag products were purchased and the fluoride level in tea infusions tested by an ion-selective electrode method. The fluoride content in all brands tested ranged from 1.6 to 6.1 mg/L, with a mean value of 3.3 mg/L. According to our risk assessment it is evident that the general population in the RoI is at a high risk of chronic fluoride exposure and associated adverse health effects based on established reference values. We conclude that the culture of habitual tea drinking in the RoI indicates that the total cumulative dietary fluoride intake in the general population could readily exceed the levels known to cause chronic fluoride intoxication. Evidence suggests that excessive fluoride intake may be contributing to a wide range of adverse health effects. Therefore from a public health perspective, it would seem prudent and sensible that risk reduction measures be implemented to reduce the total body burden of fluoride in the population. PMID:26927146

"Effect of nano-filled surface coating agent on fluoride release from conventional glass ionomer cement: an in vitro trial".

Science.gov (United States)

Tiwari, S; Nandlal, B

2013-01-01

To overcome the drawbacks of glass ionomer cement of sensitivity to initial desiccation and moisture contamination the use of surface coating agent is recommended. The search in this area led to invent of use of nanofillers in surface coating agent, but its effect on fluoride release is not clear. The aim of this study is to evaluate and compare the fluoride release from conventional glass ionomer cement with and without surface coating agent. This in vitro study comprised of total 80 samples (40 samples of each with and without surface coating). Specimens were prepared, G coat plus was applied and light cured. Fluoride release of the sample was measured every 24 h for 7 days and weekly from 7th to 21 st day using Sension4 pH/ISE/MV Meter. Descriptive Statistics, Repeated Measure ANOVA, Paired Sample t-test, Independent Sample t-test, Scheffe post hoc test. Mean values clearly reveal a significant decrease in the fluoride release from day 1 to day 21 for both groups. Non-coated group released significantly more fluoride than surface coated group (Pagent will reduce the amount of fluoride released into oral environment as compared to non-coated group and at the same time releasing fluoride into surrounding cavity walls to create zones of inhibition into the cavity floor to help internal remineralization.

Combined subchronic fluoride-lead intoxication and its attenuation with the help of a complex of bioprotectors.

Science.gov (United States)

Katsnelson, B A; Privalova, L I; Kireyeva, Y P; Yeremenko, O S; Sutunkova, M P; Valamina, I E; Varaksin, A N; Panov, V G; Kazmer, J I

2012-01-01

Combined toxicity of lead and fluoride has been studied insufficiently, and there is no known information about attempts to inhibit it with any bioprotectors. Lead acetate and sodium fluoride, administered separately or in combination, were injected i.p. to rats at isoeffective sublethal doses 3 times a week for 6 weeks. Some of the rats were exposed to the same combination against the background of oral administration of a bioprotector complex (BPC) comprising pectin, glutamate, and multivitamin/multimineral preparations. Following exposure, functional and biochemical indices and histopathological examinations of the femur of exposed and control rats were evaluated for signs of toxicity. We have shown that with regard to a number of effects on the organism level the combined toxicity of lead and fluoride may be evaluated as additive or even superadditive, but lead reduces fluoride accumulation in the bone, and pathological changes in the bone tissue proved to be less marked for combined exposure compared with separate exposures. The BPC has been demonstrated to attenuate a range of the combined harmful effects of lead and fluoride, including those on the bone tissue. In spite of the fact that fluoride and lead may reciprocally attenuate their harmful effects on the bone tissue in case of combined exposure, they prove to be more toxic for soft tissues just in combination than when administered separately. The development of combined intoxication may be substantially inhibited by means of the tested set of innocuous biologically active agents.

Structural study of chlorine tri-fluoride and bromine penta-fluoride in liquid and solid phase

International Nuclear Information System (INIS)

Rousson, R.

1973-01-01

This research thesis reports the structural study of chlorine tri-fluoride and bromine penta-fluoride between 20 C and about -265 C. After some generalities on these compounds and a presentation of the experimental technique, the author reports and discusses results obtained with these both compounds: Raman spectrum for the liquid and for the solid phase, infrared spectrum for the solid phase, calorimetric measurements. In the case of chlorine tri-fluoride, the author studies the evolution of the liquid spectrum with temperature, shows the existence of an intermediate solid phase, and compares results obtained by Raman spectroscopy and nuclear magnetic resonance. He also applies to bromine penta-fluoride an analysis of normal coordinates of a XF 5 molecule: relationship between force constants and vibration frequencies, application of Wilson method, resolution of the molecular equation, determination of normal vibration modes [fr

Current status of fluoride volatility method development

Energy Technology Data Exchange (ETDEWEB)

Uhlir, J.; Marecek, M.; Skarohlid, J. [UJV - Nuclear Research Institute, Research Centre Rez, CZ-250 68 Husinec - Rez 130 (Czech Republic)

2013-07-01

The Fluoride Volatility Method is based on a separation process, which comes out from the specific property of uranium, neptunium and plutonium to form volatile hexafluorides whereas most of fission products (mainly lanthanides) and higher transplutonium elements (americium, curium) present in irradiated fuel form nonvolatile tri-fluorides. Fluoride Volatility Method itself is based on direct fluorination of the spent fuel, but before the fluorination step, the removal of cladding material and subsequent transformation of the fuel into a powdered form with a suitable grain size have to be done. The fluorination is made with fluorine gas in a flame fluorination reactor, where the volatile fluorides (mostly UF{sub 6}) are separated from the non-volatile ones (trivalent minor actinides and majority of fission products). The subsequent operations necessary for partitioning of volatile fluorides are the condensation and evaporation of volatile fluorides, the thermal decomposition of PuF{sub 6} and the finally distillation and sorption used for the purification of uranium product. The Fluoride Volatility Method is considered to be a promising advanced pyrochemical reprocessing technology, which can mainly be used for the reprocessing of oxide spent fuels coming from future GEN IV fast reactors.

Fluoride ions vs removal technologies: A study

OpenAIRE

Singh, Jagvir; Singh, Prashant; Singh, Anuradha

2016-01-01

Literature reported that drinking water is a precious and scarce resource and it has to be protected and kept free from any kind of contamination. Further, it has to be used carefully without wasting. Literature also reported that fluoride bearing rocks are abundant in India, as a result, fluoride leaches out and contaminates the adjacent water and soil resources. A high concentration of fluoride ions in ground water increases up to more than 30 mg/L. This high concentration of fluoride ions ...

Water fluoridation in 40 Brazilian cities: 7 year analysis

Directory of Open Access Journals (Sweden)

Suzely Adas Saliba MOIMAZ

2013-01-01

Full Text Available Objectives Fluoride levels in the public water supplies of 40 Brazilian cities were analyzed and classified on the basis of risk/benefit balance. Material and Methods Samples were collected monthly over a seven-year period from three sites for each water supply source. The samples were analyzed in duplicate in the laboratory of the Center for Research in Public Health - UNESP using an ion analyzer coupled to a fluoride-specific electrode. Results A total of 19,533 samples were analyzed, of which 18,847 were artificially fluoridated and 686 were not artificially fluoridated. In samples from cities performing water fluoridation, 51.57% (n=9,720 had fluoride levels in the range of 0.55 to 0.84 mg F/L; 30.53% (n=5,754 were below 0.55 mg F/L and 17.90% (n=3,373 were above 0.84 mg F/L (maximum concentration=6.96 mg F/L. Most of the cities performing fluoridation that had a majority of samples with fluoride levels above the recommended parameter had deep wells and more than one source of water supply. There was some variability in the fluoride levels of samples from the same site and between collection sites in the same city. Conclusions The majority of samples from cities performing fluoridation had fluoride levels within the range that provides the best combination of risks and benefits, minimizing the risk of dental fluorosis while preventing dental caries. The conduction of studies about water distribution systems is suggested in cities with high natural fluoride concentrations in order to optimize the use of natural fluoride for fluoridation costs and avoid the risk of dental fluorosis.

Effect of gamma irradiation on fluoride release and antibacterial activity of resin dental materials

International Nuclear Information System (INIS)

Carvalho, Fabiola Galbiatti de; Fucio, Suzana Beatriz Portugal de; Correr-Sobrinho, Lourenco; Pascon, Fernanda Miori; Kantovitz, Kamila Rosamilia; Puppin-Rontani, Regina Maria

2009-01-01

This study evaluated the effect of gamma irradiation on fluoride release and antibacterial activity of FluroShield (FS) and Clearfil Protect Bond (CPB). Four groups were formed: G1-FS + gamma; G2-FS without gamma; G3-CPB + gamma; G4-CPB without gamma. For fluoride release analysis, 12 disks of each material were prepared and covered with nail polish, except for one side (50.4 mm 2 area). G1 and G3 were sterilized with a 14.5 KGy dose at 27 deg C for 24 h, while G2 and G4 (controls) were not sterilized and were maintained under the same time and temperature conditions. Fluoride release measurements were made in duplicate (n=6) by an ion specific electrode. The antibacterial activity of the CPB and FS against Streptococcus mutans after gamma sterilization was evaluated by the agar-disc diffusion method. The diameter of the zones of microbial growth inhibition was recorded after 48 h. Data were analyzed statistically by ANOVA and Tukey's test (alpha=5%). Gamma sterilization decreased the fluoride release of FS by approximately 50%, while CPB was not affected. There was no statistically significant difference (p>0.05) in the antibacterial effect of CPB between gamma and non-gamma sterilization groups. FS presented no antibacterial activity. Gamma irradiation decreased the fluoride release of FS, but did not affect the antibacterial activity of the studied materials. (author)

Effect of gamma irradiation on fluoride release and antibacterial activity of resin dental materials

Energy Technology Data Exchange (ETDEWEB)

Carvalho, Fabiola Galbiatti de; Fucio, Suzana Beatriz Portugal de; Correr-Sobrinho, Lourenco [Universidade Estadual de Campinas (UNICAMP), Piracicaba, SP (Brazil). Piracicaba Dental School. Dept. of Dental Materials; Pascon, Fernanda Miori; Kantovitz, Kamila Rosamilia; Puppin-Rontani, Regina Maria [Universidade Estadual de Campinas (UNICAMP), Piracicaba, SP (Brazil). Piracicaba Dental School. Dept. of Pedriatric Dentistry], e-mail: rmpuppin@fop.unicamp.br

2009-07-01

This study evaluated the effect of gamma irradiation on fluoride release and antibacterial activity of FluroShield (FS) and Clearfil Protect Bond (CPB). Four groups were formed: G1-FS + gamma; G2-FS without gamma; G3-CPB + gamma; G4-CPB without gamma. For fluoride release analysis, 12 disks of each material were prepared and covered with nail polish, except for one side (50.4 mm{sup 2} area). G1 and G3 were sterilized with a 14.5 KGy dose at 27 deg C for 24 h, while G2 and G4 (controls) were not sterilized and were maintained under the same time and temperature conditions. Fluoride release measurements were made in duplicate (n=6) by an ion specific electrode. The antibacterial activity of the CPB and FS against Streptococcus mutans after gamma sterilization was evaluated by the agar-disc diffusion method. The diameter of the zones of microbial growth inhibition was recorded after 48 h. Data were analyzed statistically by ANOVA and Tukey's test (alpha=5%). Gamma sterilization decreased the fluoride release of FS by approximately 50%, while CPB was not affected. There was no statistically significant difference (p>0.05) in the antibacterial effect of CPB between gamma and non-gamma sterilization groups. FS presented no antibacterial activity. Gamma irradiation decreased the fluoride release of FS, but did not affect the antibacterial activity of the studied materials. (author)

Vacuum-evaporated ferroelectric films and heterostructures of vinylidene fluoride/trifluoroethylene copolymer

Energy Technology Data Exchange (ETDEWEB)

Draginda, Yu. A., E-mail: lbf@ns.crys.ras.ru; Yudin, S G; Lazarev, V V; Yablonskii, S V; Palto, S P [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

2012-05-15

The potential of the vacuum method for preparing ferroelectric films and photonic heterostructures from organic materials is studied. Vacuum-evaporated films of fluoropolymers and heterostructures on their basis are obtained and their ferroelectric and spectral properties are studied. In particular, homogeneous films of the well-known piezoelectric polymer polyvinylidene fluoride and ferroelectric material vinylidene fluoride/trifluoroethylene copolymer (P(VDF/TFE)) are produced. Experimental studies of vacuum-evaporated P(VDF/TFE) films confirmed their ferroelectric properties. The heterostructures composed of alternating layers of P(VDF/TFE) copolymer molecules and azodye molecules are fabricated by vacuum evaporation. Owing to the controlled layer thickness and a significant difference in the refractive indices of the P(VDF/TFE) copolymer and azodyes, these heterostructures exhibit properties of photonic crystals. This finding is confirmed by the occurrence of a photonic band in the absorption spectra of the heterostructures.

THE USE OF FLUORIDE AND ITS EFFECT ON HEALTH

Directory of Open Access Journals (Sweden)

Domen Kanduti

2016-07-01

Full Text Available Appropriate oral health care is fundamental for any individual’s health. Dental caries is still one of the major public health problems. The most effective way of caries prevention is the use of fluoride. Fluoride occurs naturally in our environment and is always present in our lives. However, the concentration differs from area to area. Exposure can occur through diet, respiration and fluoride supplements. During pregnancy, the placenta acts as a barrier. The fluoride, therefore, crosses the placenta in low concentrations. Drinking water in Slovenia is not fluoridated; the amount of naturally present fluoride is very low. Fluoride can be toxic in extremely high concentrations. The most important effect of fluoride on caries incidence is through its role in the process of remineralisation and demineralisation of tooth enamel. The European Academy of Paediatric Dentistry (EAPD recommends a preventive topical use of fluoride supplements because of their cariostatic effect. 

Visualization of Fluoride Ions In Vivo Using a Gadolinium(III)-Coumarin Complex-Based Fluorescence/MRI Dual-Modal Probe.

Science.gov (United States)

Wang, Yue; Song, Renfeng; Feng, Huan; Guo, Ke; Meng, Qingtao; Chi, Haijun; Zhang, Run; Zhang, Zhiqiang

2016-12-16

A new Gadolinium(III)-coumarin complex, DO3A-Gd- CA , was designed and prepared as a dual-modal probe for simultaneous fluorescence and relaxivity responses to fluoride ions (F - ) in aqueous media and mice. DO3A-Gd- CA was designed by using Gd(III) center as an MRI signal output unit and fluoride binding site, and the 4-(diethylamino)-coumarin-3-carboxylic acid ( CA ) as a fluorescence reporter. Upon the addition of fluoride ions to the solution of DO3A-Gd- CA , the liberation of the coordinated CA ligand led to a 5.7-fold fluorescence enhancement and a 75% increase in the longitudinal relaxivity ( r ₁). The fluorescent detection limit for fluoride ions was determined to be 8 μM based on a 3 σ / slope . The desirable features of the proposed DO3A-Gd- CA , such as high sensitivity and specificity, reliability at physiological pH and low cytotoxicity enable its application in visualization of fluoride ion in mice. The successful in vivo imaging indicates that DO3A-Gd- CA could be potentially used in biomedical diagnosis fields.

Preparation and Characterization of Novel Polyvinylidene Fluoride/2-Aminobenzothiazole Modified Ultrafiltration Membrane for the Removal of Cr(VI in Wastewater

Directory of Open Access Journals (Sweden)

Xiuju Wang

2017-12-01

Full Text Available Hexavalent chromium is one of the main heavy metal pollutants. As the environmental legislation becomes increasingly strict, seeking new technology to treat wastewater containing hexavalent chromium is becoming more and more important. In this research, a novel modified ultrafiltration membrane that could be applied to adsorb and purify water containing hexavalent chromium, was prepared by polyvinylidene fluoride (PVDF blending with 2-aminobenzothiazole via phase inversion. The membrane performance was characterized by evaluation of the instrument of membrane performance, infrared spectroscopy (FTIR, scanning electron microscope (SEM, and water contact angle measurements. The results showed that the pure water flux of the PVDF/2-aminobenzothiazole modified ultrafiltration membrane was 231.27 L/m2·h, the contact angle was 76.1°, and the adsorption capacity of chromium ion was 157.75 µg/cm2. The PVDF/2-aminobenzothiazole modified ultrafiltration membrane presented better adsorption abilities for chromium ion than that of the traditional PVDF membrane.

Method for identifying particulate fluoride compounds

Energy Technology Data Exchange (ETDEWEB)

Tufts, B J

1960-01-01

A method is described for identifying particulates containing fluorides and other complex fluorine compounds such as fluorosilicate in samples collected on membrane filters. The filter is treated with lead chloride to precipitate lead chlorofluoride at each fluoride-containing spot. This microspot is identified by examination in a light microscope. Sulfate and phosphate, which also precipitate if present, can be distinguished and do not interfere. Calibrations are given for the fluorides and the more insoluble salts, relating the original particle size to the reaction site size. Thus, the mass of the particles can be calculated. Results of some field tests in an area of fluoride pollution are given, and compared with standard testing procedures.

Community water fluoridation on the Internet and social media.

Science.gov (United States)

Mertz, Aaron; Allukian, Myron

2014-01-01

In the United States, 95 percent of teens and 85 percent of adults use the Internet. Two social media outlets, Facebook and Twitter, reach more than 150 billion users. This study describes anti-fluoridation activity and dominance on the Internet and social media, both of which are community water fluoridation (CWF) information sources. Monthly website traffic to major fluoridation websites was determined from June 2011 to May 2012. Facebook, Twitter, and YouTube fluoridation activity was categorized as "proCWF" or "anti-CWF." Twitter's anti-CWF tweets were further subcategorized by the argument used against CWF. Anti-CWF website traffic was found to exceed proCWF activity five- to sixty-fold. Searching "fluoride" and "fluoridation" on Facebook resulted in 88 to 100 percent anti-CWF groups and pages; "fluoridation" on Twitter and YouTube resulted in 64 percent anti-CWF tweets and 99 percent anti-CWF videos, respectively. "Cancer, " "useless, " and "poisonous" were the three major arguments used against fluoridation. Anti-fluoridation information significantly dominates the Internet and social media. Thousands of people are being misinformed daily about the safety, health, and economic benefits of fluoridation.

A fully packaged self-powered sensor based on near-field electrospun arrays of poly(vinylidene fluoride nano/micro fibers

Directory of Open Access Journals (Sweden)

Y.-K. Fuh

2018-02-01

Full Text Available Energy harvesting devices based on the triboelectric and piezoelectric principles have been widely developed to scavenge wasteful and tiny mechanical energy into usable electrical energy. In particular, triboelectric energy harvesting generators with relatively simpler structure and piezoelectric fiber-based counterpart with extremely light weight compositions showed a very promising application in the self-powered sensors. In this paper, a novel hybridization of graphenebased piezoelectric generator (GBPG and graphene-PET triboelectric generator (GPTG were simultaneously packaged. The integrated structure, graphene-based hybridized self-powered sensor (GHSPS, was demonstrated to be optically transparent and mechanically robust. For the piezoelectrically harvesting device, an in-situ poling and direct-write near-field electrospinning (NFES Poly(vinylidene fluoride (PVDF piezoelectric fibers were fabricated and integrated with a single layer chemical vapor deposition (CVD grown graphene. On the other hand for GPTG counterpart, two composite layers of a single layer graphene/PET simultaneously served as triboelectrically rubbing layers as well as bottom/top electrode. This GHSPS successfully superimposed both piezoelectric and triboelectric electricity and the synergistically higher output voltage/current/power were measured as ~6 V/280 nA/172 nW in one press-and-release cycle of finger induced motion. The proposed GHSPS showed a promising application in the field of self-powered sensors to be ubiquitously implemented in the future Industry 4.0 scenarios.

Investigation of effective parameters in preparation and controlling lithium fluoride nano size powder

International Nuclear Information System (INIS)

Naderi, S.; Sarraf Mamoory, F.; Riahi Noori, N.

2007-01-01

In this research, the reaction of LiOH + HF+LiF+H 2 O has been selected and some precipitation parameters such as pH, temperature, time, super saturation, q d agitation type have been studied, and controlled. The morphology, phase analysis and particle size of the resulting powders were analyzed by SEM, XRD and LPSA. Finally, at temperature 2S d ig C , pH of about 2-3, reaction time less than 1 sec, and agitation by ultrasonic bath, the pure nano lithium fluoride powders of about 100 nm were produced

Biomonitoring Equivalents for interpretation of urinary fluoride.

Science.gov (United States)

Aylward, L L; Hays, S M; Vezina, A; Deveau, M; St-Amand, A; Nong, A

2015-06-01

Exposure to fluoride is widespread due to its natural occurrence in the environment and addition to drinking water and dental products for the prevention of dental caries. The potential health risks of excess fluoride exposure include aesthetically unacceptable dental fluorosis (tooth mottling) and increased skeletal fragility. Numerous organizations have conducted risk assessments and set guidance values to represent maximum recommended exposure levels as well as recommended adequate intake levels based on potential public health benefits of fluoride exposure. Biomonitoring Equivalents (BEs) are estimates of the average biomarker concentrations corresponding to such exposure guidance values. The literature on daily urinary fluoride excretion rates as a function of daily fluoride exposure was reviewed and BE values corresponding to the available US and Canadian exposure guidance values were derived for fluoride in urine. The derived BE values range from 1.1 to 2.1mg/L (1.2-2.5μg/g creatinine). Concentrations of fluoride in single urinary spot samples from individuals, even under exposure conditions consistent with the exposure guidance values, may vary from the predicted average concentrations by several-fold due to within- and across-individual variation in urinary flow and creatinine excretion rates and due to the rapid elimination kinetics of fluoride. Thus, the BE values are most appropriately applied to screen population central tendency estimates for biomarker concentrations rather than interpretation of individual spot sample concentrations. Copyright © 2015. Published by Elsevier Inc.

The Potential of Self-assembling Peptides for Enhancement of In Vitro Remineralisation of White Spot Lesions as Measured by Quantitative Laser Fluorescence.

Science.gov (United States)

Golland, Luca; Schmidlin, Patrick R; Schätzle, Marc

To test the remineralisation potential of a single application of self-assembling peptides or acidic fluoride solution using quantitative light-induced fluorescence (QLF) in vitro. Bovine enamel disks were prepared, and white spot lesions were created on one half of the disk with an acidic buffer solution. After demineralisation, disks were allocated into three groups of 11 specimens each. Group A served as a control group and received no treatment. Group B had a single application of fluoride, and group C was treated once with self-assembling peptides. All disks were embedded in a plastic mold (diameter 15 mm, height 9 mm) with an a-silicone, and remineralisation was initiated using a pH-cycling protocol for five days. Four experimental regions on each disk were measured prior to the start of the study (T0), after demineralisation (T1) and after the remineralisation process (T2) using QLF. After demineralisation, all areas showed a distinct loss of fluorescence, with no statistically significant difference between the groups (ΔF from -69.3 to -10.2). After remineralisation, samples of group B (treated with fluoride) showed a statistically significant fluorescence increase (ΔF from T1 to T2 15.2 ± 7.3) indicating remineralisation, whereas the samples of control group A and group C (treated with self-assembling peptides) showed no significant changes in ΔF of 1.1 ± 1.9 and 2.5 ± 1.9, respectively. Application of self-assembling peptides on demineralised bovine enamel did not lead to increased fluorescence using QLF, indicating either lack of remineralisation or irregular crystals. Increased fluorescence using QLF indicated mineral gain following a single application of a highly concentrated fluoride.

Effect of titanium tetrafluoride, amine fluoride and fluoride varnish on enamel erosion in vitro

NARCIS (Netherlands)

Vieira, A; Ruben, JL; Huysmans, MCDNJM

2005-01-01

This study aimed at evaluating the effect of 1 and 4% titanium tetrafluoride (TiF4) gels, amine fluoride (AmF) 1 and 0.25% and a fluoride varnish (FP) on the prevention of dental erosion. Two experimental groups served as controls, one with no pretreatment and another one pre-treated with a

Fluoride-induced disruption of reproductive hormones in men

International Nuclear Information System (INIS)

Ortiz-Perez, Deogracias; Rodriguez-Martinez, Manuel; Martinez, Flavio; Borja-Aburto, V.H.; Castelo, Julio; Grimaldo, J.I.; Cruz, Esperanza de la; Carrizales, Leticia; Diaz-Barriga, Fernando

2003-01-01

Fluoride-induced reproductive effects have been reported in experimental models and in humans. However, these effects were found in heavily exposed scenarios. Therefore, in this work our objective was to study reproductive parameters in a population exposed to fluoride at doses of 3-27 mg/day (high-fluoride-exposed group--HFEG). Urinary fluoride levels, semen parameters, and reproductive hormones in serum (LH, FSH, estradiol, prolactin, inhibin-B, free and total testosterone) were measured. Results were compared with a group of individuals exposed to fluoride at lower doses: 2-13 mg/day (low-fluoride-exposed group-LFEG). A significant increase in FSH (P<0.05) and a reduction of inhibin-B, free testosterone, and prolactin in serum (P<0.05) were noticed in the HFEG. When HFEG was compared to LFEG, a decreased sensitivity was found in the FSH response to inhibin-B (P<0.05). A significant negative partial correlation was observed between urinary fluoride and serum levels of inhibin-B (r=-0.333, P=0.028) in LFEG. Furthermore, a significant partial correlation was observed between a chronic exposure index for fluoride and the serum concentrations of inhibin-B (r=-0.163, P=0.037) in HFEG. No abnormalities were found in the semen parameters studied in the present work, neither in the HFEG, nor in the LFEG. The results obtained indicate that a fluoride exposure of 3-27 mg/day induces a subclinical reproductive effect that can be explained by a fluoride-induced toxic effect in both Sertoli cells and gonadotrophs

4-phenylbutyrate Mitigates Fluoride-Induced Cytotoxicity in ALC Cells

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Maiko Suzuki

2017-05-01

Full Text Available Chronic fluoride over-exposure during pre-eruptive enamel development can cause dental fluorosis. Severe dental fluorosis is characterized by porous, soft enamel that is vulnerable to erosion and decay. The prevalence of dental fluorosis among the population in the USA, India and China is increasing. Other than avoiding excessive intake, treatments to prevent dental fluorosis remain unknown. We previously reported that high-dose fluoride induces endoplasmic reticulum (ER stress and oxidative stress in ameloblasts. Cell stress induces gene repression, mitochondrial damage and apoptosis. An aromatic fatty acid, 4-phenylbutyrate (4PBA is a chemical chaperone that interacts with misfolded proteins to prevent ER stress. We hypothesized that 4PBA ameliorates fluoride-induced ER stress in ameloblasts. To determine whether 4PBA protects ameloblasts from fluoride toxicity, we analyzed gene expression of Tgf-β1, Bcl2/Bax ratio and cytochrome-c release in vitro. In vivo, we measured fluorosis levels, enamel hardness and fluoride concentration. Fluoride treated Ameloblast-lineage cells (ALC had decreased Tgf-β1 expression and this was reversed by 4PBA treatment. The anti-apoptotic Blc2/Bax ratio was significantly increased in ALC cells treated with fluoride/4PBA compared to fluoride treatment alone. Fluoride treatment induced cytochrome-c release from mitochondria into the cytosol and this was inhibited by 4PBA treatment. These results suggest that 4PBA mitigates fluoride-induced gene suppression, apoptosis and mitochondrial damage in vitro. In vivo, C57BL/6J mice were provided fluoridated water for six weeks with either fluoride free control-chow or 4PBA-containing chow (7 g/kg 4PBA. With few exceptions, enamel microhardness, fluorosis levels, and fluoride concentrations of bone and urine did not differ significantly between fluoride treated animals fed with control-chow or 4PBA-chow. Although 4PBA mitigated high-dose fluoride toxicity in vitro, a diet

4-phenylbutyrate Mitigates Fluoride-Induced Cytotoxicity in ALC Cells.

Science.gov (United States)

Suzuki, Maiko; Everett, Eric T; Whitford, Gary M; Bartlett, John D

2017-01-01

Chronic fluoride over-exposure during pre-eruptive enamel development can cause dental fluorosis. Severe dental fluorosis is characterized by porous, soft enamel that is vulnerable to erosion and decay. The prevalence of dental fluorosis among the population in the USA, India and China is increasing. Other than avoiding excessive intake, treatments to prevent dental fluorosis remain unknown. We previously reported that high-dose fluoride induces endoplasmic reticulum (ER) stress and oxidative stress in ameloblasts. Cell stress induces gene repression, mitochondrial damage and apoptosis. An aromatic fatty acid, 4-phenylbutyrate (4PBA) is a chemical chaperone that interacts with misfolded proteins to prevent ER stress. We hypothesized that 4PBA ameliorates fluoride-induced ER stress in ameloblasts. To determine whether 4PBA protects ameloblasts from fluoride toxicity, we analyzed gene expression of Tgf -β 1, Bcl2 / Bax ratio and cytochrome-c release in vitro . In vivo , we measured fluorosis levels, enamel hardness and fluoride concentration. Fluoride treated Ameloblast-lineage cells (ALC) had decreased Tgf -β 1 expression and this was reversed by 4PBA treatment. The anti-apoptotic Blc2 / Bax ratio was significantly increased in ALC cells treated with fluoride/4PBA compared to fluoride treatment alone. Fluoride treatment induced cytochrome-c release from mitochondria into the cytosol and this was inhibited by 4PBA treatment. These results suggest that 4PBA mitigates fluoride-induced gene suppression, apoptosis and mitochondrial damage in vitro . In vivo , C57BL/6J mice were provided fluoridated water for six weeks with either fluoride free control-chow or 4PBA-containing chow (7 g/kg 4PBA). With few exceptions, enamel microhardness, fluorosis levels, and fluoride concentrations of bone and urine did not differ significantly between fluoride treated animals fed with control-chow or 4PBA-chow. Although 4PBA mitigated high-dose fluoride toxicity in vitro , a diet rich

Turn-on fluorescence chemosensor for fluoride ions and its applicability in imaging of living cells

Energy Technology Data Exchange (ETDEWEB)

Ponnuvel, Kandasamy; Padmini, Vediappen, E-mail: padimini_tamilenthi@yahoo.co.in

2016-01-15

The study was easy to prepare fluorescent chemosensor, the urea based triphenylamine conjugated ligand and structurally simple anion probes displayed great selectivity for the fluoride anion over other anions in an aqueous tetrahydrofuran solution. The probe was characterized using NMR spectroscopy, UV–visible, emission spectroscopy and mass spectrometry. The sensor showed spectral shifts and intensity changes in the presence of fluoride anions. The Job’s plot analysis indicates that the binding stoichiometry to be 1:1. Furthermore, by means of confocal fluorescent microscopy experiments, it has been demonstrated that it can be used as a fluorescent probe for monitoring fluoride ions in the living cells. - Highlights: • A novel fluorescent chemosensor for the detection of F{sup −} anions. • Detection of F{sup −} anions can be performed in water at pH=7.4. • The chemosensor could be efficiently delivered to live cells for bioimaging of F{sup −}.

Chronic fluoride toxicity: dental fluorosis.

Science.gov (United States)

Denbesten, Pamela; Li, Wu

2011-01-01

Dental fluorosis occurs as a result of excess fluoride ingestion during tooth formation. Enamel fluorosis and primary dentin fluorosis can only occur when teeth are forming, and therefore fluoride exposure (as it relates to dental fluorosis) occurs during childhood. In the permanent dentition, this would begin with the lower incisors, which complete mineralization at approximately 2-3 years of age, and end after mineralization of the third molars. The white opaque appearance of fluorosed enamel is caused by a hypomineralized enamel subsurface. With more severe dental fluorosis, pitting and a loss of the enamel surface occurs, leading to secondary staining (appearing as a brown color). Many of the changes caused by fluoride are related to cell/matrix interactions as the teeth are forming. At the early maturation stage, the relative quantity of amelogenin protein is increased in fluorosed enamel in a dose-related manner. This appears to result from a delay in the removal of amelogenins as the enamel matures. In vitro, when fluoride is incorporated into the mineral, more protein binds to the forming mineral, and protein removal by proteinases is delayed. This suggests that altered protein/mineral interactions are in part responsible for retention of amelogenins and the resultant hypomineralization that occurs in fluorosed enamel. Fluoride also appears to enhance mineral precipitation in forming teeth, resulting in hypermineralized bands of enamel, which are then followed by hypomineralized bands. Enhanced mineral precipitation with local increases in matrix acidity may affect maturation stage ameloblast modulation, potentially explaining the dose-related decrease in cycles of ameloblast modulation from ruffle-ended to smooth-ended cells that occur with fluoride exposure in rodents. Specific cellular effects of fluoride have been implicated, but more research is needed to determine which of these changes are relevant to the formation of fluorosed teeth. As further

Health effects of fluoride pollution caused by coal burning

Energy Technology Data Exchange (ETDEWEB)

Ando, M.; Tadano, M.; Yamamoto, S.; Tamura, K.; Chen, X. [Regional Environment Division, National Institute for Environmental Studies, Tsukuba, 305-0083 Ibaraki (Japan); Asanuma, S. [Japan Institute of Rural Medicine, Usuda, Nagano (Japan); Watanabe, T. [Saku Central Hospital, Usuda, Nagano (Japan); Kondo, T. [Matsumoto Dental College, Shiojiri, Nagano (Japan); Sakurai, S. [Otsuma Women' s University, Tama, Tokyo (Japan); Ji, R.; Liang, C.; Cao, S. [Institute of Environmental Health and Engineering, Beijing (China); Hong, Z. [Shanxi Maternity and Children' s Hospital, Taiyuan (China)

2001-04-23

Recently a huge amount of fluoride in coal has been released into indoor environments by the combustion of coal and fluoride pollution seems to be increasing in some rural areas in China. Combustion of coal and coal bricks is the primary source of gaseous and aerosol fluoride and these forms of fluoride can easily enter exposed food products and the human respiratory tract. Major human fluoride exposure was caused by consumption of fluoride contaminated food, such as corn, chilies and potatoes. For each diagnostic syndrome of dental fluorosis, a log-normal distribution was observed on the logarithm of urinary fluoride concentration in students in China. Urinary fluoride content was found to be a primary health indicator of the prevalence of dental fluorosis in the community. In the fluorosis areas, osteosclerosis in skeletal fluorosis patients was observed with a high prevalence. A biochemical marker of bone resorption, urinary deoxypyridinoline content was much higher in residents in China than in residents in Japan. It was suggested that bone resorption was stimulated to a greater extent in residents in China and fluoride may stimulate both bone resorption and bone formation. Renal function especially glomerular filtration rate was very sensitive to fluoride exposure. Inorganic phosphate concentrations in urine were significantly lower in the residents in fluorosis areas in China than in non-fluorosis area in China and Japan. Since airborne fluoride from the combustion of coal pollutes extensively both the living environment and food, it is necessary to reduce fluoride pollution caused by coal burning.

Fluoride removal performance of glass derived hydroxyapatite

Energy Technology Data Exchange (ETDEWEB)

Liang, Wen, E-mail: wliang@ecust.edu.cn [Research Institute of Biomaterials, School of Materials Science and Engineering, East China University of Science and Technology (China); Zhan, Lei; Piao, Longhua [Research Institute of Biomaterials, School of Materials Science and Engineering, East China University of Science and Technology (China); Russel, Christian [Otto-Schott-Institut, Universitaet Jena, Jena (Germany)

2011-02-15

Research highlights: {yields} Novel sodium calcium borate glass derived hydroxyapatite (G-HAP) is prepared. {yields} Micro-G-HAP adsorbs F{sup -} ions in solutions more effectively than commercial nano-HAP. {yields} The adsorption kinetics and isotherms are well fitted by a second order kinetic model and Freundlich isotherm model. -- Abstract: A novel sodium calcium borate glass derived hydroxyapatite (G-HAP) with different ranges of particle size was prepared by immersion sodium calcium borate glass in 0.1 M K{sub 2}HPO{sub 4} solution by the ratio of 50 g L{sup -1} for 7 days. The unique advantage of G-HAP for the adsorption of fluoride ions in solutions was studied. The effects of size and quantity of particles, pH value and adsorption time on adsorption performance were investigated. The maximum adsorption capacity was 17.34 mg g{sup -1} if 5 g L{sup -1}, <100 {mu}m G-HAP was added to a solution with an initial pH value of 6.72 and the adsorption time was 12 h. The results showed that the micro-G-HAP could immobilize F{sup -} in solution more effectively than commercial nano-HAP, which makes potential application of the G-HAP in removing the fluoride ions from wastewater. The adsorption kinetics and isotherms for F{sup -} could be well fitted by a second order kinetic model and Freundlich isotherm model respectively, which could be used to describe the adsorption behavior. The mechanism of G-HAP in immobilizing F{sup -} from aqueous solutions was investigated by the X-ray diffraction (XRD), infrared spectra (IR) and scanning electron microscopy (SEM).

Thermodynamic data-base for metal fluorides

Energy Technology Data Exchange (ETDEWEB)

Yoo, Jae Hyung; Lee, Byung Gik; Kang, Young Ho and others

2001-05-01

This study is aimed at collecting useful data of thermodynamic properties of various metal fluorides. Many thermodynamic data for metal fluorides are needed for the effective development, but no report of data-base was published. Accordingly, the objective of this report is to rearrange systematically the existing thermodynamic data based on metal fluorides and is to use it as basic data for the development of pyrochemical process. The physicochemical properties of various metal fluorides and metals were collected from literature and such existing data base as HSC code, TAPP code, FACT code, JANAF table, NEA data-base, CRC handbook. As major contents of the thermodynamic data-base, the physicochemical properties such as formation energy, viscosity, density, vapor pressure, etc. were collected. Especially, some phase diagrams of eutectic molten fluorides are plotted and thermodynamic data of liquid metals are also compiled. In the future, the technical report is to be used as basic data for the development of the pyrochemical process which is being carried out as a long-term nuclear R and D project.

Thermodynamic data-base for metal fluorides

International Nuclear Information System (INIS)

Yoo, Jae Hyung; Lee, Byung Gik; Kang, Young Ho and others

2001-05-01

This study is aimed at collecting useful data of thermodynamic properties of various metal fluorides. Many thermodynamic data for metal fluorides are needed for the effective development, but no report of data-base was published. Accordingly, the objective of this report is to rearrange systematically the existing thermodynamic data based on metal fluorides and is to use it as basic data for the development of pyrochemical process. The physicochemical properties of various metal fluorides and metals were collected from literature and such existing data base as HSC code, TAPP code, FACT code, JANAF table, NEA data-base, CRC handbook. As major contents of the thermodynamic data-base, the physicochemical properties such as formation energy, viscosity, density, vapor pressure, etc. were collected. Especially, some phase diagrams of eutectic molten fluorides are plotted and thermodynamic data of liquid metals are also compiled. In the future, the technical report is to be used as basic data for the development of the pyrochemical process which is being carried out as a long-term nuclear R and D project

Cytotoxic effects of glass ionomer cements on human dental pulp stem cells correlate with fluoride release.

Science.gov (United States)

Kanjevac, Tatjana; Milovanovic, Marija; Volarevic, Vladislav; Lukic, Miodrag L; Arsenijevic, Nebojsa; Markovic, Dejan; Zdravkovic, Nebojsa; Tesic, Zivoslav; Lukic, Aleksandra

2012-01-01

Glass ionomer cements (GICs) are commonly used as restorative materials. Responses to GICs differ among cell types and it is therefore of importance to thoroughly investigate the influence of these restorative materials on pulp stem cells that are potential source for dental tissue regeneration. Eight biomaterials were tested: Fuji I, Fuji II, Fuji VIII, Fuji IX, Fuji Plus, Fuji Triage, Vitrebond and Composit. We compared their cytotoxic activity on human dental pulp stem cells (DPSC) and correlated this activity with the content of Fluoride, Aluminium and Strontium ions in their eluates. Elution samples of biomaterials were prepared in sterile tissue culture medium and the medium was tested for toxicity by an assay of cell survival/proliferation (MTT test) and apoptosis (Annexin V FITC Detection Kit). Concentrations of Fluoride, Aluminium and Strontium ions were tested by appropriate methods in the same eluates. Cell survival ranged between 79.62% (Fuji Triage) to 1.5% (Fuji Plus) and most dead DPSCs were in the stage of late apoptosis. Fluoride release correlated with cytotoxicity of GICs, while Aluminium and Strontium ions, present in significant amount in eluates of tested GICs did not. Fuji Plus, Vitrebond and Fuji VIII, which released fluoride in higher quantities than other GICs, were highly toxic to human DPSCs. Opposite, low levels of released fluoride correlated to low cytotoxic effect of Composit, Fuji I and Fuji Triage.

Metal fluoride complexes of Na,K-ATPase: characterization of fluoride-stabilized phosphoenzyme analogues and their interaction with cardiotonic steroids.

Science.gov (United States)

Cornelius, Flemming; Mahmmoud, Yasser A; Toyoshima, Chikashi

2011-08-26

The Na,K-ATPase belongs to the P-type ATPase family of primary active cation pumps. Metal fluorides like magnesium-, beryllium-, and aluminum fluoride act as phosphate analogues and inhibit P-type ATPases by interacting with the phosphorylation site, stabilizing conformations that are analogous to specific phosphoenzyme intermediates. Cardiotonic steroids like ouabain used in the treatment of congestive heart failure and arrhythmias specifically inhibit the Na,K-ATPase, and the detailed structure of the highly conserved binding site has recently been described by the crystal structure of the shark Na,K-ATPase in a state analogous to E2·2K(+)·P(i) with ouabain bound with apparently low affinity (1). In the present work inhibition, and subsequent reactivation by high Na(+), after treatment of shark Na,K-ATPase with various metal fluorides are characterized. Half-maximal inhibition of Na,K-ATPase activity by metal fluorides is in the micromolar range. The binding of cardiotonic steroids to the metal fluoride-stabilized enzyme forms was investigated using the fluorescent ouabain derivative 9-anthroyl ouabain and compared with binding to phosphorylated enzyme. The fastest binding was to the Be-fluoride stabilized enzyme suggesting a preformed ouabain binding cavity, in accord with results for Ca-ATPase where Be-fluoride stabilizes the E2-P ground state with an open luminal ion access pathway, which in Na,K-ATPase could be a passage for ouabain. The Be-fluoride stabilized enzyme conformation closely resembles the E2-P ground state according to proteinase K cleavage. Ouabain, but not its aglycone ouabagenin, prevented reactivation of this metal fluoride form by high Na(+) demonstrating the pivotal role of the sugar moiety in closing the extracellular cation pathway.

Molten fluoride fuel salt chemistry

International Nuclear Information System (INIS)

Toth, L.M.; Del Cul, G.D.; Dai, S.; Metcalf, D.H.

1995-01-01

The chemistry of molten fluorides is traced from their development as fuels in the Molten Salt Reactor Experiment with important factors in their selection being discussed. Key chemical characteristics such as solubility, redox behavior, and chemical activity are explained as they relate to the behavior of molten fluoride fuel systems. Development requirements for fitting the current state of the chemistry to modern nuclear fuel system are described. It is concluded that while much is known about molten fluoride behavior which can be used effectively to reduce the amount of development required for future systems, some significant molten salt chemical questions must still be addressed. copyright American Institute of Physics 1995

Milk fluoridation for the prevention of dental caries

Directory of Open Access Journals (Sweden)

Jolán Bánóczy

2013-11-01

Full Text Available The aim of this review is to give an overview of 55 years experience of milk fluoridation and draw conclusions about the applicability of the method. Fluoridated milk was first investigated in the early 1950s, almost simultaneously in Switzerland, the USA and Japan. Stimulated by the favourable results obtained from these early studies, the establishment of The Borrow Dental Milk Foundation (subsequently The Borrow Foundation in England gave an excellent opportunity for further research, both clinical and non-clinical, and a productive collaboration with the World Health Organization which began in the early 1980s. Numerous peer-reviewed publications in international journals showed clearly the bioavailability of fluoride in various types of milk. Clinical trials were initiated in the 1980s – some of these can be classed as randomised controlled trials, while most of the clinical studies were community preventive programmes. Conclusion. These evaluations showed clearly that the optimal daily intake of fluoride in milk is effective in preventing dental caries. The amount of fluoride added to milk depends on background fluoride exposure and age of the children: commonly in the range 0.5 to 1.0 mg per day. An advantage of the method is that a precise amount of fluoride can be delivered under controlled conditions. The cost of milk fluoridation programmes is low, about € 2 to 3 per child per year. Fluoridation of milk can be recommended as a caries preventive measure where the fluoride concentration in drinking water is suboptimal, caries experience in children is significant, and there is an existing school milk programme.

Milk fluoridation for the prevention of dental caries.

Science.gov (United States)

Bánóczy, Jolán; Rugg-Gunn, Andrew; Woodward, Margaret

2013-11-01

The aim of this review is to give an overview of 55 years experience of milk fluoridation and draw conclusions about the applicability of the method. Fluoridated milk was first investigated in the early 1950s, almost simultaneously in Switzerland, the USA and Japan. Stimulated by the favourable results obtained from these early studies, the establishment of The Borrow Dental Milk Foundation (subsequently The Borrow Foundation) in England gave an excellent opportunity for further research, both clinical and non-clinical, and a productive collaboration with the World Health Organization which began in the early 1980s. Numerous peer-reviewed publications in international journals showed clearly the bioavailability of fluoride in various types of milk. Clinical trials were initiated in the 1980s - some of these can be classed as randomised controlled trials, while most of the clinical studies were community preventive programmes. These evaluations showed clearly that the optimal daily intake of fluoride in milk is effective in preventing dental caries. The amount of fluoride added to milk depends on background fluoride exposure and age of the children: commonly in the range 0.5 to 1.0 mg per day. An advantage of the method is that a precise amount of fluoride can be delivered under controlled conditions. The cost of milk fluoridation programmes is low, about € 2 to 3 per child per year. Fluoridation of milk can be recommended as a caries preventive measure where the fluoride concentration in drinking water is suboptimal, caries experience in children is significant, and there is an existing school milk programme. Copyright © 2013 by Academy of Sciences and Arts of Bosnia and Herzegovina.

Preparation of copper-beryllium alloys from Indian beryl

International Nuclear Information System (INIS)

Paul, C.M.; Sharma, B.P.; Subba Rao, K.S.; Rajadhyaksha, M.G.; Sundaram, C.V.

1975-01-01

The paper presents the results of laboratory-scale investigations on the preparation of copper-beryllium and aluminium beryllium master alloys starting from Indian beryl and adopting the fluoride process. The flowsheet involves: (1) conversion of the Be-values in beryl into water soluble sodium beryllium fluoride, (2) preparation of beryllium hydroxide by alkali treatment of aqueous Na 2 BeF 4 (3) conversion of Be(OH) 2 to (NH 4 ) 2 BeF 4 by treatment with NH 4 HF 2 (4) thermal decomposition of (NH 4 ) 2 BeF 4 to BeF 2 and (5) magnesium reduction of BeF 2 (without/with) the addition of copper/aluminium to obtain beryllium metal/alloys. The method has been successfully employed for the preparation of Cu-Be master alloys containing about 8% Be and free of Mg on a 200 gm scale. A1-80% Be master alloys have also been prepared by this method. Toxicity and health hazards associated with Be are discussed and the steps taken to ensure safe handling of Be are described. (author)

Poisoning by coal smoke containing arsenic and fluoride

Energy Technology Data Exchange (ETDEWEB)

An, D.; He, Y.G.; Hu, Q.X. [Guizhou Sanitary and Epidemiological Station, Guiyang (China)

1997-02-01

An investigation was made into a disease involving skin pigmentation, keratosis of the hands and feet, dental discoloration, and generalized bone and joint pain, stiffness and rigidity, in the village of Bazhi, Zhijin County, Ghizhou Province, People`s Republic of China. Measurements were made of the arsenic and fluoride levels of coal, water, air, food, urine and hair in Bazhi and a control village, Xinzhai, in which coal with a low arsenic content was used. Up to 188 people, including children, in Bazhi and 752 in Xinzhai, were examined for the presence of chronic arsenium, skeletal fluorosis, dental fluorosis and electrocardiogram abnormalities. The coal in Bazhi was found to contain high levels of arsenic and fluoride resulting, after burning in homes without an adequate chimney systems, in pollution of air and food with arsenic and fluoride. The coal in Xinzhai did not cause arsenic pollution but did produce a higher level of fluoride pollution. It was concluded that the endemic disease in Bazhi was caused by pollution by coal smoke containing arsenic and fluoride. It is suggested that arsenic may act synergistically with fluoride so that a lower level of fluoride may produce fluoride toxicity with dental and skeletal fluorosis.

New Insight on the Response of Bacteria to Fluoride

Science.gov (United States)

Breaker, R.R.

2012-01-01

Fluoride has been used for decades to prevent caries and it is well established that this anion can inhibit the growth of bacteria. However, the precise effects that fluoride has on bacteria and the mechanisms that bacteria use to overcome fluoride toxicity have largely remained unexplored. Recently, my laboratory reported the discovery of biological systems that bacteria use to sense fluoride and reduce fluoride toxicity. These sensors and their associated genes are very widespread in biology, which has implications for a number of issues that are central to the use of fluoride for dental care. Below I provide a summary of our findings, comment on some of the key prospects for expanding our understanding of fluoride's effects on biology, and propose some future uses of this knowledge. PMID:22327376

New insight on the response of bacteria to fluoride.

Science.gov (United States)

Breaker, R R

2012-01-01

Fluoride has been used for decades to prevent caries and it is well established that this anion can inhibit the growth of bacteria. However, the precise effects that fluoride has on bacteria and the mechanisms that bacteria use to overcome fluoride toxicity have largely remained unexplored. Recently, my laboratory reported the discovery of biological systems that bacteria use to sense fluoride and reduce fluoride toxicity. These sensors and their associated genes are very widespread in biology, which has implications for a number of issues that are central to the use of fluoride for dental care. Below I provide a summary of our findings, comment on some of the key prospects for expanding our understanding of fluoride's effects on biology, and propose some future uses of this knowledge. Copyright © 2012 S. Karger AG, Basel.

Bone fluoride determination for clinical investigation of osteoporosis

International Nuclear Information System (INIS)

Krishnan, S.S.; McNeill, K.G.; Hitchman, A.J.W.; Mernagh, J.R.; Lin, S.C.; Harrison, J.E.

1984-01-01

Sodium fluoride is the therapeutic agent known to stimulate bone growth with net increase in bone mineral mass in patients afflicted with osteoporosis, a common crippling bone disease. In order to study the effect of sodium fluoride treatment, a method of analysis for fluoride in bone has been developed using Neutron Activation Analysis (NAA). The technique proved to be simple, fast, reliable and non-destructive. Thus the sample, often bone biopsy specimen, is available, after fluoride analysis, for further histological studies. NAA was used to analyze both fluoride and calcium in the bone and the results expressed as F/Ca ratio was meaningful since it normalizes the fluoride to bone mineral mass which is the important factor in this study. Four years of fluoride treatment of osteoporotics showed significant increase of bone mass (up to 30%) in several patients. These increases were associated with histological bone picture of fluorosis. In the case of patients with renal osteodystrophy, there was evidence that fluorosis contributes to the bone disease. 3 references, 2 figures, 2 tables

Sustainable approach for recycling waste lamb and chicken bones for fluoride removal from water followed by reusing fluoride-bearing waste in concrete.

Science.gov (United States)

Ismail, Zainab Z; AbdelKareem, Hala N

2015-11-01

Sustainable management of waste materials is an attractive approach for modern societies. In this study, recycling of raw waste lamb and chicken bones for defluoridation of water has been estimated. The effects of several experimental parameters including contact time, pH, bone dose, fluoride initial concentration, bone grains size, agitation rate, and the effect of co-existing anions in actual samples of wastewater were studied for fluoride removal from aqueous solutions. Results indicated excellent fluoride removal efficiency up to 99.4% and 99.8% using lamb and chicken bones, respectively at fluoride initial concentration of 10 mg F/L and 120 min contact time. Maximum fluoride uptake was obtained at neutral pH range 6-7. Fluoride removal kinetic was well described by the pseudo-second order kinetic model. Both, Langmuir and Freundlich isotherm models could fit the experimental data well with correlation coefficient values >0.99 suggesting favorable conditions of the process. Furthermore, for complete sustainable management of waste bones, the resulted fluoride-bearing sludge was reused in concrete mixes to partially replace sand. Tests of the mechanical properties of fluoride sludge-modified concrete mixes indicated a potential environmentally friendly approach to dispose fluoride sludge in concrete and simultaneously enhance concrete properties. Copyright © 2015 Elsevier Ltd. All rights reserved.

New Insight on the Response of Bacteria to Fluoride

OpenAIRE

Breaker, R.R.

2012-01-01

Fluoride has been used for decades to prevent caries and it is well established that this anion can inhibit the growth of bacteria. However, the precise effects that fluoride has on bacteria and the mechanisms that bacteria use to overcome fluoride toxicity have largely remained unexplored. Recently, my laboratory reported the discovery of biological systems that bacteria use to sense fluoride and reduce fluoride toxicity. These sensors and their associated genes are very widespread in biolog...

Widespread genetic switches and toxicity resistance proteins for fluoride.

Science.gov (United States)

Baker, Jenny L; Sudarsan, Narasimhan; Weinberg, Zasha; Roth, Adam; Stockbridge, Randy B; Breaker, Ronald R

2012-01-13

Most riboswitches are metabolite-binding RNA structures located in bacterial messenger RNAs where they control gene expression. We have discovered a riboswitch class in many bacterial and archaeal species whose members are selectively triggered by fluoride but reject other small anions, including chloride. These fluoride riboswitches activate expression of genes that encode putative fluoride transporters, enzymes that are known to be inhibited by fluoride, and additional proteins of unknown function. Our findings indicate that most organisms are naturally exposed to toxic levels of fluoride and that many species use fluoride-sensing RNAs to control the expression of proteins that alleviate the deleterious effects of this anion.

Mechanical and electro-mechanical properties of three-dimensional nanoporous graphene-poly(vinylidene fluoride composites

Directory of Open Access Journals (Sweden)

G. P. Zheng

2016-09-01

Full Text Available Three-dimensional nanoporous graphene monoliths are utilized to prepare graphene-poly(vinylidene fluoride nanocomposites with enhanced mechanical and electro-mechanical properties. Pre-treatment of the polymer (poly(vinylidene fluoride, PVDF with graphene oxides (GOs facilitates the formation of uniform and thin PVDF films with a typical thickness below 100 nm well coated at the graphene nano-sheets. Besides their excellent compressibility, ductility and mechanical strength, the nanoporous graphene-PVDF nanocomposites are found to possess high sensitivity in strain-dependent electrical conductivity. The improved mechanical and electro-mechanical properties are ascribed to the enhanced crystalline β phase in PVDF which possesses piezoelectricity. The mechanical relaxation analyses on the interfaces between graphene and PVDF reveal that the improved mechanical and electro-mechanical properties could result from the interaction between the –C=O groups in the nanoporous graphene and the –CF2 groups in PVDF, which also explains the important role of GOs in the preparation of the graphene-polymer nanocomposites with superior combined mechanical and electro-mechanical properties.

Comparison of shear bond strength of self-etching fluoride releasing adhesives with and without pumice prophylaxis

Directory of Open Access Journals (Sweden)

V R Shobbana Devi

2015-01-01

Conclusions: Fluoride releasing adhesives combined with antibacterial monomer can play a vital role in reducing white spot lesions by enhancing the cariostatic effect especially in noncompliant\\medically compromised patients.

Evaluation and Assessment of Fluoride in Drinking Water Wells Damavand Villages Zoning in GIS According to DMF Index

Directory of Open Access Journals (Sweden)

Kave Kheirkhah Rahimabad

2016-09-01

Full Text Available Background:Fluoride is one the vital anions and the drinking water is the main source of preparing it for the human body. Nonetheless, the aim of this paper is to investigate the Fluoride rate in water supplying wells by using GIS environment according to decay, missing or filled (DMF index.  Methods: This research is an analytic and cross-sectional descriptive study with sampling approach of 12 water supplying wells of Damavand villages in summer and autumn the year 2013. The Fluoride concentration was measured by standard method SPADNS using MN-Nano color 400 Photometer in laboratory of Rural Water and Wastewater Company of Tehran. Then DMF was investigated for local students and finally the obtained data were modeled in GIS. Results: The average of Fluoride concentration was 0.094 to 0.212 mg/L in summer and 0.137 to 3.48 mg/L in autumn. The DMF index was estimated around 5.46 for all evaluated students that the mentioned index was 7.635 and 3.29 for male and female pupils respectively which are statistically significant difference. Conclusion: The amounts of fluorine in drinking water supplies in rural Damavand villages are lower than the international water standards. According to the results of experiments and lack of fluorine ion in the villages of this town, required fluorine should be done by drinkable water fluoridation and continuities of implementation plan for fluoride ion among the schools until reaching the fluoride concentration to the standard threshold, Supplying required fluorine of body by mouth-wash materials for people of this region

Risk perception, psychological heuristics and the water fluoridation controversy.

Science.gov (United States)

Perrella, Andrea M L; Kiss, Simon J

2015-04-29

Increasingly, support for water fluoridation has come under attack. We seek an explanation, focusing on the case of Waterloo, Ontario, where a 2010 referendum overturned its water fluoridation program. In particular, we test whether individuals perceive the risks of water fluoridation based not on 'hard' scientific evidence but on heuristics and cultural norms. A sample of 376 residents in Waterloo were surveyed in June 2012 using random digit dialing. We use factor analysis, OLS regression, as well as t-tests to evaluate a survey experiment to test the credibility hypothesis. Perceptions of fluoride as a risk are lower among those who perceive fluoride's benefits (B = .473, p < 0.001) and those whose cultural view is 'egalitarian' (B = .156, p < 0.05). The experiment shows a lower level of perception of fluoride's benefits among respondents who are told that water fluoridation is opposed by a national advocacy group (Group A) compared to those who are told that the government and the World Health Organization support fluoridation (Group B) (t = 1.6547, p < 0.05), as well as compared to the control group (t = 1.8913, p < 0.05). There is no difference between Group B and the control, possibly because people's already general support for fluoridation is less prone to change when told that other public organizations also support fluoridation. Public health officials should take into account cultural norms and perceptions when individuals in a community appear to rise up against water fluoridation, with implications for other public health controversies.

Antibacterial Effect of Silver Diamine Fluoride on Cariogenic Organisms.

Science.gov (United States)

Lou, Yali; Darvell, Brain W; Botelho, Michael G

2018-05-01

To screen the possible antimicrobial activity of a range of clinically used, silver-based compounds on cariogenic organisms: silver diamine fluoride (SDF), silver fluoride, and silver nitrate. Preliminary screening disk-diffusion susceptibility tests were conducted on Mueller-Hinton agar plates inoculated with Streptococcus mutans, Lactobacillus acidophilus, and Actinomyces naeslundii, organisms known to be cariogenic. In order to identify which component of the silver compounds was responsible for any antibacterial (AB) effect, and to provide controls, the following were also investigated at high and low concentrations: sodium fluoride, ammonium fluoride, ammonium chloride, sodium fluoride, sodium chloride, and sodium nitrate, as well as deionized water as control. A volume of 10 pL of a test solution was dispensed onto a paper disk resting on the inoculated agar surface, and the plate incubated anaerobically at 37°C for 48 hours. The zones of inhibition were then measured. Silver diamine fluoride, silver fluoride, silver nitrate, and ammonium fluoride had significant AB effect (p effect at low concentration; the remaining other compounds had no effect. Silver ions appear to be the principal AB agent at both high and low concentration; fluoride ions only have an AB effect at high concentration, while ammonium, nitrate, chloride and sodium ions have none. The anticaries effect of topical silver solutions appears restricted to that of the silver ions. Silver compounds, such as SDF, silver fluoride, and silver nitrate have AB effect against cariogenic organisms and these may have clinical impact in arresting or preventing dental decay. Sodium fluoride did not have AB effect under the conditions tested.

High Fluoride Dentifrices for Elderly and Vulnerable Adults

DEFF Research Database (Denmark)

Ekstrand, Kim Rud

2016-01-01

The primary aim of this work is to present the available evidence that toothpastes containing >1,500 ppm fluoride (2,500-2,800 and 5,000 ppm F) provide an additional caries preventive effect on root caries lesions in elderly patients compared to traditional dentifrices (1,000-1,450 ppm F......). The secondary aim of this paper is to discuss why high fluoride dentifrices in general should perform better than traditional F-containing toothpaste. When examining the few studies that have considered the preventive benefits of high fluoride products on root caries the relative risk appears to be around 0.......5, and the risk can thus be halved by exchanging traditional F-containing toothpaste for toothpaste containing 5,000 ppm F. There is reasonable evidence that high fluoride dentifrices significantly increase the fluoride concentration in saliva during the day and the fluoride concentration in plaque compared...

The effects of processing conditions on the surface morphology and hydrophobicity of polyvinylidene fluoride membranes prepared via vapor-induced phase separation

Science.gov (United States)

Peng, Yuelian; Fan, Hongwei; Ge, Ju; Wang, Shaobin; Chen, Ping; Jiang, Qi

2012-12-01

The present investigation reveals how the surface morphology and the hydrophobicity of polyvinylidene fluoride (PVDF) membranes, which were prepared via a vapor-induced phase separation method, were affected by the initial PVDF content in the casting solution and the air temperature. The surface morphology was characterized with scanning electron microscopy. A ternary phase diagram of PVDF/N, N-dimethylacetamide/water was constructed to explain the formation mechanism of the different morphologies. The results show that different membrane morphologies and hydrophobicities can be obtained by changing the processing conditions. Low air temperature and high PVDF contents facilitate the crystallization process, resulting in the formation of a porous skin and particle morphology, which increases the hydrophobicity of the surface. High air temperature and low PVDF contents are favorable for the formation of a net-like surface morphology via spinodal decomposition and lead to a superhydrophobic surface. Theoretical calculations were performed to testify that the net-like surface was more favorable for superhydrophobicity than the particle-based surface.

Adsorption and exhaustion device for gaseoue uranium fluorides

International Nuclear Information System (INIS)

Kida, Yasuo; Nakamura, Yuichi.

1984-01-01

Purpose: To prevent gaseous uranium fluorides from passing through the adsorption layer upon exhausting the gaseous uranium, fluorides from a uranium fluoride processing facility through adsorption traps, by controlling the flow rate of the gaseous uranium fluorides passing through the layer constant. Constitution: An adsorption trap is connected by way of pipeways to a uranium fluoride processing facility, and a flow rate detector for detecting the flow rate of gaseous uranium fluorides and a pressure gauge for detecting the pressure at the inlet of the adsorption trap are disposed to the pipeways. The setting value for the pressure control is calculated from the detection value of the flow rate detector by the pressure control gage. Then, an operation amount for the pressure control valve is calculated based on the deviatoin between the setting value for the pressure control and the inlet pressure at the adsorption trap. This enables to control the flow rate of the gaseous uranium fluorides passing through the adsorption layer always constant thereby enabling to prevent excess increase in the flow rate which results in damages in the adsorption layer. (Moriyama, K.)

The effective use of fluorides in public health

DEFF Research Database (Denmark)

Jones, Sheila; Burt, Brian A; Petersen, Poul Erik

2005-01-01

, systematic reviews summarizing these extensive databases have indicated that water fluoridation and fluoride toothpastes both substantially reduce the prevalence and incidence of dental caries. We present four case studies that illustrate the use of fluoride in modern public health practice, focusing on......Dental caries remain a public health problem for many developing countries and for underprivileged populations in developed countries. This paper outlines the historical development of public health approaches to the use of fluoride and comments on their effectiveness. Early research...

Absorption, distribution and excretion of inhaled hydrogen fluoride in the rat

Energy Technology Data Exchange (ETDEWEB)

Morris, J.B.

1979-01-01

Rats were subjected to whole body HF exposure for 6 hrs or to nose-only HF exposure for 1 hr. Total and/or ionic fluoride concentrations in selected tissues were determined at various times following exposure. In rats sacrificed 6 hrs after whole body exposure, dose-dependent increases in lung, plasma, and kidney total and ionic fluoride concentration occurred. Rats excreted more fluoride in the urine after whole body exposure than could be explained by the amount of HF inhaled. Considerable evidence suggests that airborne HF deposits on fur and is then ingested due to preening activity. Urinary fluoride excretion was increased by nose-only exposure. The urinary fluoride excretion accounted for approximately twice the fluoride estimated to be inhaled during exposure. Tissue fluoride concentrations were elevated immediately after nose-only exposure. Fluoride concentrations in lung and kidney returned to control levels within 12 hrs. Plasma fluoride concentration was slightly elevated 24 hrs after the start of the 1 hr exposure but was at control levels at 96 hrs. Immediately following nose-only exposure, lung ionic fluoride concentrations were less than plasma ionic fluoride concentrations suggesting that the fluoride in the lung had reached that site via plasma transport rather than by inhalation. A dose-dependent increase in plasma ionic fluoride concentration occurred after upper respiratory tract HF exposure providing strong evidence that fluoride is absorbed systemically from that site. The plasma ionic fluoride concentration after upper respiratory tract exposure was of sufficient magnitude to account for the plasma fluoride concentrations observed in intact nose-only exposed rats. (ERB)

Fluoride release and recharge behavior of a nano-filled resin-modified glass ionomer compared with that of other fluoride releasing materials.

Science.gov (United States)

Mitra, Sumita B; Oxman, Joe D; Falsafi, Afshin; Ton, Tiffany T

2011-12-01

To compare the long-term fluoride release kinetics of a novel nano-filled two-paste resin-modified glass-ionomer (RMGI), Ketac Nano (KN) with that of two powder-liquid resin-modified glass-ionomers, Fuji II LC (FLC) and Vitremer (VT) and one conventional glass-ionomer, Fuji IX (FIX). Fluoride release was measured in vitro using ion-selective electrodes. Kinetic analysis was done using regression analysis and compared with existing models for GIs and compomers. In a separate experiment the samples of KN and two conventional glass-ionomers, FIX and Ketac Molar (KM) were subjected to a treatment with external fluoride source (Oral-B Neutra-Foam) after 3 months of fluoride release and the recharge behavior studied for an additional 7-day period. The cumulative amount of fluoride released from KN, VT and FLC and the release profiles were statistically similar but greater than that for FIX at P coating of KN with its primer and of DY with its adhesive did not significantly alter the fluoride release behavior of the respective materials. The overall rate for KN was significantly higher than for the compomer DY. DY showed a linear rate of release vs. t and no burst effect as expected for compomers. The nanoionomer KN showed fluoride recharge behavior similar to the conventional glass ionomers FIX and KM. Thus, it was concluded that the new RMGI KN exhibits fluoride ion release behavior similar to typical conventional and RMGIs and that the primer does not impede the release of fluoride.

The chemistry of two-component fluoride crystalline optical media for heavy, fast, radiation hard scintillators

International Nuclear Information System (INIS)

Sobolev, B.P.; Krivandina, E.A.; Fedorov, P.P.; Vasilchenko, V.G.

1994-01-01

Prospects for preparation of two-component dense optical materials for scintillators are shown, using data on phase diagrams of about 300 MF m - RF n (m, n ≤ 4) type systems, formed by metal fluorides. Primary characteristics (decay time and light output of luminescence, radiation hardness, etc.) of some multicomponent crystals are reported

Fluoridation Basics

Science.gov (United States)

... return on investment for community water fluoridation (including productivity losses) ranged from $4 in small communities of ... National Center for Chronic Disease Prevention and Health Promotion Email Recommend Tweet YouTube Instagram Listen Watch RSS ...

The Effect of Fluoridated and Non Fluoridated Mouth Washes on Color Stability of Different Aesthetic Arch Wires At Different Time Intervals (An in Vitro Study

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Lubna Maky Hussein

2018-01-01

Full Text Available Background:The color stability of aesthetic arch wires is an important factor in the success of an aesthetic orthodontic treatment, but the color of these arch wires tends to change with time.This study was performed to assess the effect of two types of mouth washes on the color  stability of different types of aesthetic arch wires at different time intervals. Materials and methods:Four brands of nickel titanium coated aesthetic arch wires were used: epoxy coated (Orthotechnology and G&H and Teflon coated (Dany and Hubit.Thirty six samples were prepared, each sample contains ten halves of the aesthetic arch wires. They were divided into three groups according to the immersion media (distilled water as a control media, Listerine with fluoride and Listerine without fluoride and immersed for 30 seconds twice daily according to manufacturer's instructions to measure color change after 1 week, 3 weeks and 6 weeks by using spectrophotometer VITA Easyshade Compact according to Commission Internationale de l’Eclairage L*a*b* color space system. Results:It was found that there were highly significant differences in color change values of aesthetic arch wires among all immersion media at different time intervals and color change value increases as the time of immersion increases.Additionally, Listerine with fluoride mouth wash caused higher color change values of aesthetic arch wires than Listerine without fluoride and Hubit aesthetic arch wires were the least color stable while Orthotechnology aesthetic arch wires were the most color stable. Conclusions: We can conclude that the daily use of Listerine mouth washes could affect on the color stability of aesthetic arch wires. Although all tested aesthetic arch wires revealed color changes at variable degrees but some of these changes were not  visible and the others were clinically acceptable while the remaining were clinically unacceptable.

Fluoride removal performance of phosphoric acid treated lime ...

African Journals Online (AJOL)

Fluoride in drinking water above permissible levels is responsible for dental and skeletal fluorosis. In this study, removal of fluoride ions from water using phosphoric acid treated lime was investigated in continuous and point-of-use system operations. In the continuous column operations, fluoride removal performance was ...

Preparation of 99mTc-PQQE and preliminary biological evaluation for the NMDA receptor

International Nuclear Information System (INIS)

Zhou Xingqin; Kong Yanyan; Zou Meifen; Zhang Jiankang; Cao Guoxian

2013-01-01

The 4, 5-dioxo-4, 5-dihydro-1H-pyrrolo(2, 3-f)quinoline-2, 7, 9-tricarboxylic acid 2-ethyl ester 7, 9-dimethyl ester (PQQE) was synthesized on the basis of Pyrroloquinoline quinine (PQQ). 99m Tc-PQQE was prepared using stannous fluoride (SnF 2 ) as reducing agent. Biological characteristics of 99m Tc-PQQE include lipophilic and the charge properties were compared to 99m Tc-PQQ. The biodistributions of 99m Tc-PQQE in mice and brain regional distribution were performed. In vivo distribution of 99m Tc-PQQE in mice indicates that the concentration ratio of drug and blood increases steadily over time. The major radioactivity may be metabolized by the hepatic and renal system. The elimination-phase half-time (t1/2 β) results indicate that the residence time of 99m Tc-PQQE (203.92) in the body is twice as long as 99m Tc-PQQ (100.45)., The uptake of 99n Tc- P QQE in brain was improved due to the ameliorating of charge and lipophilicity. The highest total regional brain uptake of 99m Tc-PQQE was in the frontal lobe and hippocampus, where the NMDA receptor is very abundant. 99m Tc-PQQE had a good target to nontarget ratio (hippocampus/cerebellum) which preserved a higher value (peak 4.0 at 120 min) from 60 min to 180 min after injection. In vitro autoradiographic results are in close agreement with the regional brain map. The enrichment can be blocked by N-methyl-D-aspartate receptor (NMDAR) redox modulatory site antagonists-ebselen (EB). This work suggests that 99m Tc-PQQE has some specific targeting to the NMDA receptor. (authors)

Clinical significance of technetium-99m stannous pyrophosphate myocardial scintigrams in patients with acute and old myocardial infarction

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Kanazawa, Ikuo; Eno, Shin; Takeuchi, Masaaki

1987-08-01

Seventy-five consecutive patients with acute (43) or old (32) myocardial infarction (AMI, OMI) have been examined by myocardial scintiscanning with technetium-99m stannous pyrophosphate (PYP). Using Parker's classification, the PYP scans were graded as positive in 56 % of the AMI patients; in restricting to the PYP scans obtained within the first 3 days after the onset, the positive rate was 86 %. Positive or negative PYP scans for the AMI patients were independent of maximum creatine phosphokinase and infarct site. For OMI patients, the PYP scans were positive in 41 %, with decreased left ventricular function being more common than those having negative PYP scans. In the group of positive scans, clinical manifestations tended to be remarkable, which were likely due to persistent cardiac ischemia during chronic stage. (Namekawa, K.).

Fluoride uptake from restorative dental materials by human enamel

International Nuclear Information System (INIS)

Forsten, L.; Rytoemaa, I.; Anttila, A.; Keinonen, J.

1976-01-01

The purpose of the study was to determine the uptake in vitro of fluoride from restorative materials by tooth enamel and whether prior etching of the enamel causes a change of uptake. The outermost layer of the labial surface of extracted canines was removed by grinding and the enamel was covered with five different fluoride-containing materials ; a silicate, a composite resin, an amalgam, a silicophosphate, and a polycarboxylate luting cement. The material was either removed immediately or after storing the tooth in distilled water. The fluoride content was determined using a sensitive physical method based on the 19 F (p, αγ) 16 O reaction. In addition, the fluoride content of enamel after etching for different periods of time and of etched enamel which had been in contact with silicate cement was determined. The mean fluoride content of uncovered interior enamel was 226 parts 10 6 . All materials, except the composite, increased clearly the fluoride content of the underlying enamel. Etching of interior enamel also increased the fluoride values. No difference could be shown in fluoride uptake from silicate and composite resin between etched and unetched enamel. (author)

Removal of fluoride from drinking water using a modified fly ash adsorbent

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Debasis Goswami; Arabinda K. Das

2006-01-15

Fly ash from a coal-fired power station was chemically modified and utilized for the removal of fluoride from drinking water. Two types of beds were used. Bed I was prepared by treatment with 12M HCl followed by neutralization with 5M NaOH solution. The reaction mass was filtered, washed, dried, and crushed to fine powder. Bed I material was mixed with alum and MgCl{sub 2} solutions and treated with 0.9M Na{sub 2}CO{sub 3} until pH reached to 4.5. Mass was again filtered, washed, dried at 120{sup o}C for 4 h and crushed to fine powder. This bed material is Bed II, which was used for defluoridation. Bed I was used to maintain pH (7.5-8.5) of the final effluent. Fluoride (100 ppm) present in both synthetic mixtures and drinking water samples was allowed to pass through Bed II (15 g) absorbent and effluents were found to contain no fluoride but pH of the effluent was 5.4-5.5. To maintain WHO guidelines for drinking water on pH, this effluent was again passed through Bed I. The effectiveness of the modified fly ash bed was satisfactory.

Fluoride ion recognition by chelating and cationic boranes.

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Hudnall, Todd W; Chiu, Ching-Wen; Gabbaï, François P

2009-02-17

Because of the ubiquity of fluoride ions and their potential toxicity at high doses, researchers would like to design receptors that selectively detect this anion. Fluoride is found in drinking water, toothpaste, and osteoporosis drugs. In addition, fluoride ions also can be detected as an indicator of uranium enrichment (via hydrolysis of UF(6)) or of the chemical warfare agent sarin, which releases the ion upon hydrolysis. However, because of its high hydration enthalpy, the fluoride anion is one of the most challenging targets for anion recognition. Among the various recognition strategies that are available, researchers have focused a great deal of attention on Lewis acidic boron compounds. These molecules typically interact with fluoride anions to form the corresponding fluoroborate species. In the case of simple triarylboranes, the fluoroborates are formed in organic solvents but not in water. To overcome this limitation, this Account examines various methods we have pursued to increase the fluoride-binding properties of boron-based receptors. We first considered the use of bifunctional boranes, which chelate the fluoride anion, such as 1,8-diborylnaphthalenes or heteronuclear 1-boryl-8-mercurio-naphthalenes. In these molecules, the neighboring Lewis acidic atoms can cooperatively interact with the anionic guest. Although the fluoride binding constants of the bifunctional compounds exceed those of neutral monofunctional boranes by several orders of magnitude, the incompatibility of these systems with aqueous media limits their utility. More recently, we have examined simple triarylboranes whose ligands are decorated by cationic ammonium or phosphonium groups. These cationic groups increase the electrophilic character of these boranes, and unlike their neutral analogs, they are able to complex fluoride in aqueous media. We have also considered cationic boranes, which form chelate complexes with fluoride anions. Our work demonstrates that Coulombic and chelate

Fluoride adsorption from aqueous solution by magnetic core-shell Fe_3O_4@alginate-La particles fabricated via electro-coextrusion

International Nuclear Information System (INIS)

Zhang, Yahui; Lin, Xiaoyan; Zhou, Quisheng; Luo, Xuegang

2016-01-01

Graphical abstract: The magnetic core-shell Fe_3O_4@Alg-La particles were fabricated successfully by a simple method of electro-coextrusion, and employed as an adsorbent for separation of fluoride from aqueous solution. - Highlights: • Magnetic core-shell Fe_3O_4@Alg-La particles were prepared by electro-coextrusion. • The maximum adsorption capacity for fluoride at 298.15 K was 45.230 mg/g. • The adsorbent has a good saturation magnetization value. • The adsorbent has a great potential in removing the fluoride. - Abstract: The magnetic core-shell Fe_3O_4@Alg-La particles were fabricated successfully by a simple method of electro-coextrusion, and employed as an adsorbent for separation of fluoride from aqueous solution. Main factors affecting the removal of fluoride, including pH, adsorbent dosage, initial concentration, temperature and contact time were investigated. The adsorption isotherm and adsorption kinetics were studied to understand the adsorption process in detail. The experimental data were fitted well by the non-linear Freundlich isotherm and linear pseudo-second-order model, the maximum fluoride adsorption capacity was 45.230 mg/g at pH 4, 298.15 K. Thermodynamic parameters indicated that the fluoride adsorption process was feasible and spontaneous. The presence of other anions like Cl"−, SO_4"2"−, HCO_3"− and PO_4"3"− had almost no effect on the fluoride adsorption. The adsorbent can be easily separated from the solution by a magnet. The magnetic core-shell Fe_3O_4@Alg-La particles before and after fluoride adsorption were studied by SEM, FTIR, EDX and XPS, which indicated that the adsorption mechanism may be related to electrostatic attraction and Lewis acid-base interaction.

Preparation of 99mTc-Ancitabine as a Possible Tumor Imaging Agent

International Nuclear Information System (INIS)

Ibrahim, I.T.; Attallah, K.M.

2010-01-01

Ancitabine is one of the potent chemotherapeutic anticancer drugs. Tc-Ancitabine ( 99m Tc-ANC) was prepared using stannous chloride as reducing agent, which produced yield above 90% at ph 4 at room temperature within 1-5 min as reaction time. The labeled drug was stable for more than 8 h post labeling. Biodistribution study of 99m Tc-ANC in normal mice reflected that its uptake was increased in organ of high proliferation like stomach. In solid tumor bearing mice 99m Tc-ANC was incorporated rapidly in tumor site and declined slowly, while it was declined rapidly from other tissues. Biodistribution of 99m Tc-ANC in solid tumor presented a possible model for imaging of tumors.

Fluoride use in Controlling Dental Caries and Fluorosis

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Gaurav Solanki

2012-07-01

Full Text Available Policy were introduced to control fluoride exposure and to reduce the prevalence of fluorosis. The study aimed of describing the prevalence, severity and risk factors for fluorosis, and to describe the trend of fluorosis among Indian children. The study also aimed of exploring the effect of the change in fluoride exposure on dental fluorosis and caries. Establishing an appropriate use of fluoride toothpaste could be successful in reducing fluorosis without a significant increase in caries experience. The use of fluorides for oral health has always involved a balance between the protective benefit against dental caries and the risk of developing fluorosis. The link between fluoride and dental health was established to determining the causes of dental fluorosis or enamel mottling. Fluorosis in Indian children was highly prevalent in the early 1990s.

Fluoride remediation using floating macrophytes

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Naba Kumar Mondal

2014-04-01

Full Text Available Six aquatic macrophytes, such as Pistia stratiotes, Ceratophyllum demersum, Nymphoides indica, Lemna major, Azolla pinnata,and Eichhornia crassipes were considered for remove fluoride from aqueous solution. Five different concentrations (10, 30, 50, and 100 ppm of fluoride solution were taken in 1 L plastic container. Fixed weight (20 g of macrophytes along with 500 ml fluoride solution was taken in each plastic container for 72 hours observation. Results demonstrated all the macrophytes show highest fluoride removal during 24 h to 48 h, but after 72 h their efficiency reduced drastically. The species N. indica showed better removal efficiency than other experimental macrophytes. In general, pigment measurement data indicated higher concentration at 72 h. However, Pistia sp. showed higher concentration of pigmentation at intermediate time interval (48 h. Higher level of dry weight to fresh weight ratio was recorded for L. major and A. pinnata at all concentrations, excepting at 10 ppm. In addition, all macrophytes showed lower RGR at higher concentration. Isotherm study indicated that macrophyte C. demersum is a good fitted with Freundlich and Langmuir isotherm whereas L. major with Langmuir isotherm during 24 hours.

Self-assembled structures of 1,3:2,4-di(3,4-dimethylbenzylidene) sorbitol in hydrophobic polymer matrices prepared using different heat treatments

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Lai, Wei-Chi; Tseng, Shen-Jhen; Huang, Po-Hsun

2015-11-01

We report a method for tuning the nanoarchitectures of 1,3:2,4-di(3,4-dimethylbenzylidene) sorbitol (DMDBS) with poly(vinylidene fluoride) (PVDF) polymer matrices. Hydrophobic PVDF facilitated the formation of nanofibrils during heating. The self-assembly behaviors of DMDBS were further tuned by altering the different heat treatments. When the samples were prepared with a rapid heating rate (shorter annealing time), smaller amounts of melted PVDF were excluded due to the shorter time for aggregation of DMDBS, leading to larger complex structures of DMDBS and PVDF. Therefore, longer and thicker nanofibrils (around 100 nm) were observed using scanning electron microscopy. As the samples were prepared with a slow heating rate (longer annealing time), DMDBS had more time to aggregate, and therefore, larger amounts of melted PVDF were excluded. Smaller complex structures of DMDBS and PVDF caused the formation of shorter and thinner nanofibrils (around 40 nm). In addition, small-angle X-ray scattering results indicated that the longer and thicker nanofibrils were mostly excluded outside the PVDF crystalline bundles after cooling because they were too large to be easily incorporated between the PVDF crystalline lamellae. However, a large portion of the smaller and thinner nanofibrils was trapped between the crystalline lamellae after cooling due to their smaller sizes. As expected, the PVDF spherulitic morphologies were affected, but the PVDF crystalline microstructures were not significantly altered by the addition of DMDBS, as shown by the results from polarized optical microscopy and Fourier transform infrared spectroscopy.

Morphology and performance of polyvinylidene fluoride/perfluoro sulphonic acid hollow fiber ultrafiltration blend membranes

International Nuclear Information System (INIS)

Yuan, Guo-Lin; Xu, Zhen-Liang; Wei, Yong-Ming; Yu, Li-Yun

2009-01-01

Polyvinylidene fluoride-perfluoro sulphonic acid hollow fibre ultrafiltration blend membranes were prepared by wet-spinning method. Polyvinylpyrrolidone and ethanol aqueous solutions were employed as additive and coagulants, respectively. The effect of Polyvinylpyrrolidone concentration in the dopes and ethanol concentration in the coagulants on morphology and performance of Polyvinylidene fluoride -perfluoro sulphonic acid hollow fibre ultrafiltration blend membranes were investigated. Blend membranes were characterized in terms of precipitation kinetics, morphology, thermal property and separation performance. The results showed that the increments of Polyvinylpyrrolidone concentration in the dopes and ethanol concentration in coagulants both resulted in higher pure water permeation flux and worse rejection (R) of bovine serum albumin (with the increment of Polyvinylpyrrolidone concentration from 0 to 5 wt% in the dopes, pure water permeation increased from 41.7 L.m -2 .h -1 to 134 L.m -2 .h -1 and R decreased from 99.8% to 84.4% as well as with the increase in ethanol concentration in coagulants from 0 to 40 wt%, pure water permeation increased from 33.5 L.m -2 .h- 1 to 123 L.m -2 .h -1 and R decreased from 97.7% to 88.7%). However, the proportion of sponge-like structure in the cross-section of membranes decreased with the increasing Polyvinylpyrrolidone concentration in the dopes and the proportion increased with the increased ethanol concentration in the coagulations. In addition, the location of the sponge-like structure in the cross-section of membranes was significantly influenced by ethanol concentrations in the coagulants and differential scanning calorimeter results revealed that the crystallinity (X c ) of the blend membrane was in accordance with the proportion of sponge-like structure. These behaviours were attributed to the different roles of Polyvinylpyrrolidone in the dopes and ethanol in the coagulants, respectively. Polyvinylidene fluoride

Density and surface tension of melts of zirconium and hafnium fluorides with lithium fluoride

International Nuclear Information System (INIS)

Katyshev, S.F.; Artemov, V.V.; Desyatnik, V.N.

1988-01-01

A study was conducted to determine the temperature dependence of the density and surface tension of melts of LiF-ZrF 4 and LiF-HfF 4 . Density and surface tension were determined by the method of maximum pressure in an argon bubble. On the basis of experimental data over the entire concentration range the molar volumes and their relative deviations from the additive molar volumes were calculated for 1100 0 K. The positive deviations of the molar volumes from additivity in the LiF-HfF 4 system (22.45%) were greater than in the LiF-ZrF 4 system (15.75%). This indicated that the reaction with lithium fluoride is intensified with the switch to the hafnium fluoride. Results also demonstrated that the fluorides are surface-active components in the molten mixtures

On the Eu{sup 2+} luminescence in some perovskite fluorides

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Belsare, P. D., E-mail: pankajbelsare@gmail.com [Department of Physics, Priyadarshini Institute of Engineering and Technology, Nagpur-440019 (India); Joshi, C. P. [Department of Physics, Shri Ramdeobaba C.O.E.M., Katol Road, Nagpur-440013 (India); Moharil, S. V., E-mail: svmoharil@yahoo.com [Department of Physics, R.T.M. Nagpur University Nagpur-440010 (India); Omanwar, S. K. [Department of Physics, S.G.B.Amravati University, Amravati-444602 (India)

2015-08-28

In the recent years due to their various optical and technological applications fluoride materials have attracted attention of several researchers. When these materials are doped with rare earth ions they show properties favorable for many optical applications such as high quantum efficiencies. The perovskite type fluorides of formula ABF{sub 3} where A= Alkali earth metal (Li,Na,K,Rb,Cs) and B= Alkaline earth metal (Mg,Ca,Ba,Sr) are of special interest to the research workers because of their wide range of applications that includes these materials as thermoluminescence detector, laser material, scintillator, X-ray imaging and storage phosphor, quantum cutter for VUV applications etc. Due to the high symmetry and technological efficiency of the growth process these crystals are good model objects for fundamental studies and in some cases they are of great practical value. This paper reports photoluminescence properties of UV emitting KMgF{sub 3}, NaMgF{sub 3} and LiBaF{sub 3} phosphors prepared by reactive atomospheric process. X-ray diffraction and photoluminescence characteristics of these phosphors are also mentioned.

Coprecipitation of iron and silver with barium fluoride

International Nuclear Information System (INIS)

Kopilova, N.V.; Khamidov, B.O.; Kashina, Z.A.; Ikrami, D.D.

1986-01-01

Distribution of trace contaminants of iron and silver at coprecipitation of barium fluoride is studied in present work. It is defined that iron almost completely coprecipitated with barium fluoride in wide range of ph 5.5-12. Silver coprecipitated with barium fluoride in ph range 4-7. The value of coprecipitation varies from 94% to 100%.

Preparation of copper-beryllium alloys from Indian beryl

International Nuclear Information System (INIS)

Paul, C.M.; Sharma, B.P.; Subba Rao, K.S.; Rajadhyaksha, M.G.; Sundaram, C.V.

1975-01-01

The report presents the results of laboratory scale investigations on the preparation of copper-beryllium and aluminium-beryllium master alloys starting from Indian beryl and adopting the fluoride process. The flow-sheet involves : (1) conversion of the Be-values in beryl into water soluble sodium beryllium fluoride (2) preparation of beryllium hydroxide by alkali treatment of aqueous Na 2 BeF 4 (3) conversion of Be(OH) 2 to (NH 4 ) 2 BeF 4 by treatment with NH 4 HF 2 (4) thermal decomposition of (NH 4 ) 2 BeF 4 to BeF 2 and (5) magnesium reduction of BeF 2 (with the addition of copper/aluminium) to obtain beryllium alloys. The method has been successfully employed for the preparation of Cu-Be master alloys containing about 8% Be and free of Mg on a 200 gm scale. An overall Be-recovery of about 80% has been achieved. Al-8% Be master alloys have also been prepared by this method. Toxicity and health hazards associated with Be are discussed and the steps taken to ensure safe handling of Be are described. (author)

42 CFR 137.360 - Does the Secretary approve project planning and design documents prepared by the Self-Governance...

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2010-10-01

... design documents prepared by the Self-Governance Tribe? 137.360 Section 137.360 Public Health PUBLIC... HUMAN SERVICES TRIBAL SELF-GOVERNANCE Construction Roles of the Secretary in Establishing and... documents prepared by the Self-Governance Tribe? The Secretary shall have at least one opportunity to...

Data on fluoride concentration level in villages of Asara (Alborz, Iran) and daily fluoride intake based on drinking water consumption.

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Akhavan, Giti; Dobaradaran, Sina; Borazjani, Jaleh Mohajeri

2016-12-01

In the present data article, fluoride concentration levels of drinking water (with spring or groundwater sources) in 10 villages of Asara area located in Alborz province were determined by the standard SPADNS method using a spectrophotometer (DR/2000 Spectrophotometer, USA). Daily fluoride intakes were also calculated based on daily drinking water consumption. The fluoride content were compared with EPA and WHO guidelines for drinking water.

ADSORPTIVE REMOVAL OF FLUORIDE FROM WATER USING ...

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Currently available treatment methods for removal of excess fluoride from water are broadly divided into three ... the application of nanoparticles as sorbents for fluoride removal. Sundaram [26] studied the ... Characterization of adsorbent.

Process development for treatment of fluoride containing wastes

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Singh, Mahesh; Kanvinde, V Y [Chemical Engineering Division, Bhabha Atomic Research Centre, Mumbai (India)

1994-06-01

Many chemical and metallurgical industries generate liquid wastes containing high values of fluorides in association of nitrates and other metals. Due to harmful effects of fluorides these type of wastes can not be disposed off in the environment without proper treatment. Bench-scale laboratory experiments were conducted to develop a process scheme to fix the fluorides as non-leachable solid waste and fluoride free treated liquid waste for their disposal. To optimize the important parameters, simulated synthetic and actual wastes were used. For this study, three waste streams were collected from Nuclear Fuel Complex, Hyderabad. (author). 6 tabs., 1 fig.

Toxicity of fluoride to microorganisms in biological wastewater treatment systems.

Science.gov (United States)

Ochoa-Herrera, Valeria; Banihani, Qais; León, Glendy; Khatri, Chandra; Field, James A; Sierra-Alvarez, Reyes

2009-07-01

Fluoride is a common contaminant in a variety of industrial wastewaters. Available information on the potential toxicity of fluoride to microorganisms implicated in biological wastewater treatment is very limited. The objective of this study was to evaluate the inhibitory effect of fluoride towards the main microbial populations responsible for the removal of organic constituents and nutrients in wastewater treatment processes. The results of short-term batch bioassays indicated that the toxicity of sodium fluoride varied widely depending on the microbial population. Anaerobic microorganisms involved in various metabolic steps of anaerobic digestion processes were found to be very sensitive to the presence of fluoride. The concentrations of fluoride causing 50% metabolic inhibition (IC(50)) of propionate- and butyrate-degrading microorganisms as well as mesophilic and thermophilic acetate-utilizing methanogens ranged from 18 to 43 mg/L. Fluoride was also inhibitory to nitrification, albeit at relatively high levels (IC(50)=149 mg/L). Nitrifying bacteria appeared to adapt rapidly to fluoride, and a near complete recovery of their metabolic activity was observed after only 4d of exposure to high fluoride levels (up to 500 mg/L). All other microbial populations evaluated in this study, i.e., glucose fermenters, aerobic glucose-degrading heterotrophs, denitrifying bacteria, and H(2)-utilizing methanogens, tolerated fluoride at very high concentrations (>500 mg/L).

Laboratory investigations into the potential anticaries efficacy of fluoride varnishes.

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Lippert, Frank; Hara, Anderson Takeo; Martinez-Mier, Esperanza Angeles; Zero, Domenick T

2014-01-01

The purpose of this study was to investigate the potential anticaries efficacy of fluoride varnishes (FVs) by studying their ability to reharden and deliver fluoride to carious lesions and to release fluoride into saliva. Enamel carious lesions were created and allocated to 24 groups (11 FVs with two FV incubation times and two control groups) based on Knoop microhardness test values. FVs were applied to lesions, which were incubated in artificial saliva for two or six hours, with saliva being renewed hourly. FV was removed and lesions were remineralized in artificial saliva for 22 hours. Microhardness was measured and enamel fluoride uptake (EFU) was determined. Saliva samples (six-hour groups) were analyzed to determine fluoride release characteristics. Data were analyzed using analysis of variance. FVs differed considerably in their ability to reharden and deliver fluoride to carious lesions and in their fluoride release characteristics. Little consistency was found between investigated study variables for virtually all tested FVs. For example, a particular FV showed the highest EFU and fluoride release values but the lowest rehardening value. A longer FV contact time led to increased EFU for five of the 11 FVs. Some FVs delivered more fluoride to lesions in two hours than others did in six hours. Fluoride varnishes differ greatly in their in vitro anticaries efficacy.

Protective effect of fluoride varnish and fluoride gel on enamel erosion: roughness, SEM-EDS, and µ-EDXRF studies.

Science.gov (United States)

Soares, Luís Eduardo Silva; De Carvalho Filho, Antonio Carlos Belfort

2015-03-01

The effects of fluoride treatment on bovine enamel subjected to acid erosion were studied by roughness (Ra) measurements, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and microenergy-dispersive X-ray fluorescence spectrometry (μ-EDXRF). Enamel samples (63) were divided into nine groups (n = 7): artificial saliva (AS), Pepsi Twist(®) (PT), orange juice (OJ), Duraphat(®)  + Pepsi Twist(®) (DPH/PT), Duraphat(®)  + orange juice (DPH/OJ), Duofluorid(®)  + Pepsi Twist(®) (DUO/PT), Duofluorid(®)  + orange juice (DUO/OJ), fluoride gel + Pepsi Twist(®) (FG/PT), and fluoride gel + orange juice (FG/OJ). Fluoride was applied and the samples were submitted to six cycles (demineralization: Pepsi Twist(®) or orange juice, 10 min; remineralization: saliva, 1 h). The enamel surface in depth was exposed and 63 line-scan maps were performed. The elemental analysis by EDS revealed that only fluoride treated groups had any detectable fluorine after erosion cycles (DPH/PT: 3.50 wt%; DPH/OJ: 3.37 wt%; DUO/PT: 2.69 wt%; DUO/OJ: 3.54 wt%; FG/PT: 2.17 wt%; FG/OJ: 2.77 wt%). PT treatment resulted in significantly higher Ra values than the artificial saliva (P < 0.001). Scanning electron microscopy (SEM) analysis of fluoride protected enamel showed areas with some globular structures or a residual layer of varnish. The enamel thickness was significantly lower in PT (0.63 ± 0.087 mm) than in DPH/PT (0.87 ± 0.16 mm) and DUO/PT (0.92 ± 0.14 mm) groups (P < 0.01). Fluoride treatments protected enamel without Ra increase and loss of enamel tissue. © 2015 Wiley Periodicals, Inc.

Water fluoridation for the prevention of dental caries.

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Iheozor-Ejiofor, Zipporah; Worthington, Helen V; Walsh, Tanya; O'Malley, Lucy; Clarkson, Jan E; Macey, Richard; Alam, Rahul; Tugwell, Peter; Welch, Vivian; Glenny, Anne-Marie

2015-06-18

Dental caries is a major public health problem in most industrialised countries, affecting 60% to 90% of school children. Community water fluoridation was initiated in the USA in 1945 and is currently practised in about 25 countries around the world; health authorities consider it to be a key strategy for preventing dental caries. Given the continued interest in this topic from health professionals, policy makers and the public, it is important to update and maintain a systematic review that reflects contemporary evidence. To evaluate the effects of water fluoridation (artificial or natural) on the prevention of dental caries.To evaluate the effects of water fluoridation (artificial or natural) on dental fluorosis. We searched the following electronic databases: The Cochrane Oral Health Group's Trials Register (to 19 February 2015); The Cochrane Central Register of Controlled Trials (CENTRAL; Issue 1, 2015); MEDLINE via OVID (1946 to 19 February 2015); EMBASE via OVID (1980 to 19 February 2015); Proquest (to 19 February 2015); Web of Science Conference Proceedings (1990 to 19 February 2015); ZETOC Conference Proceedings (1993 to 19 February 2015). We searched the US National Institutes of Health Trials Registry (ClinicalTrials.gov) and the World Health Organization's WHO International Clinical Trials Registry Platform for ongoing trials. There were no restrictions on language of publication or publication status in the searches of the electronic databases. For caries data, we included only prospective studies with a concurrent control that compared at least two populations - one receiving fluoridated water and the other non-fluoridated water - with outcome(s) evaluated at at least two points in time. For the assessment of fluorosis, we included any type of study design, with concurrent control, that compared populations exposed to different water fluoride concentrations. We included populations of all ages that received fluoridated water (naturally or artificially

Water Fluoridation Reporting System (Public Water Systems)

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U.S. Department of Health & Human Services — The Water Fluoridation Reporting System (WFRS) has been developed to provide tools to assist states in managing fluoridation programs. WFRS is designed to track all...

FLUORIDE CONTENT OF COMMERCIALLY AVAILABLE SOY MILK PRODUCTS IN THAILAND.

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Rirattanapong, Opas; Rirattanapong, Praphasri

2016-01-01

Abstract. In Thailand, the consumption of soy milk products is common but there is limited data about their fluoride content. The purpose of this study was to es- timate the fluoride content of soy milk products available in Thailand. Fluoride content was determined for 76 brands of soy milk using a F-ion-specific electrode. The fluoride concentrations ranged from 0.01 to 3.78 μg/ml. The fluoride content was not related to sugar content, soy bean content or the sterilization process. Among 3 brands of soy milk containing tea powder extract, the fluoride content was high (1.25 to 3.78 μg/ml). Most brands of soy milk tested in our study had fluoride content below the optimal daily intake but brands containing tea powder extract if consumed by children may increase their risk for fluorosis.

Fluoride removal from water by nano filtration

International Nuclear Information System (INIS)

Bejaoui, Imen; Mnif, Amine; Hamrouni, Bechir

2009-01-01

As any oligo element, fluoride is necessary and beneficial for human health to low concentrations, but an excess amount of fluoride ions in drinking water has been known to cause undesirable effects, especially tooth and bones fluoro sis. The maximum acceptable concentration of fluoride in drinking water was fixed by the World Health Organization according to the climate in the range of 1 mg.L -1 to 1,2 mg.L -1 . Many methods have been used to remove fluoride from water such as precipitation, adsorption, electrocoagulation and membrane processes. Technologies using membrane processes are being used in many applications, particularly for brackish water desalination. Nano filtration seems to be the best process for a good selective defluorination of fluorinated waters. The main objective of this work was to investigate the retention of fluoride anions by nano filtration. The first part of this study deals with the characterisation of the NF HL2514TF membrane. The influence of various experimental parameters such as initial fluoride content, feed pressure, permeate flux, ionic strength, type of cation associated to fluoride and pH were studied in the second part. Results show that the retention order for the salts tested was TR(Na 2 SO 4 ) > TR(CaCl 2 ) > TR(NaCl), showing a retention sequence inversely proportional to the salt diffusion coefficients in water. It was also shown that charge effects could not be neglected, and a titration experiments confirmed that the NF membrane carry a surplus of negatively charged groups. Fluoride retention exceeds 60 pour cent, and increases with increasing concentration, where the rejection mechanism is related to the dielectric effects. Speigler-Kedem model was applied to experimental results in the aim to determine phenomenological parametersσand P s respectively, the reflexion coefficient of the membrane and the solute permeability of ions. The convective and diffusive parts of the mass transfer were quantified with

Studies on the comparative effect of sodium fluoride on collagen ...

African Journals Online (AJOL)

Fluoride is an essential element for the normal development and growth of human beings. The main source of fluoride for humans is the intake of groundwater. At high levels, fluoride causes dental and skeletal fluorosis. In this study, control and sodium fluoride (NaF) treated groups of rats had significant (p < 0.05) higher ...

Spectrophotometric determination of fluoride with alizarin complexone

Energy Technology Data Exchange (ETDEWEB)

Marczenko, Z; Lenarczyk, L [Politechnika Warszawska (Poland)

1976-01-01

The modification of direct spectrophotometric method of fluoride determination by alizarin complexone has been developed. It was shown that the lanthanum alizarin complexone chelate is more convenient than that of cerium (3). The influence of acetone, dioxane and dimethyl sulphoxide in water solution on the increase of sensitivity of the method and the rate of colour reaction has been determined. The optimal pH ranges for the reaction with lanthanum and cerium (3) have been estimated. Some amines having a large molecule are useful for extraction of blue fluoride complex with isobutanol. Dioctylamine was applied in a new extraction spectrophotometric procedure of fluoride determination. Conditions in reagent have been established. Both variants of the method have been applied to the fluoride determination in several chemicals. The obtained results show a good precision and accuracy.

Removal of fluoride from water using aluminium containing compounds

Institute of Scientific and Technical Information of China (English)

M. Karthikeyan; K. P. Elango

2009-01-01

Batch adsorption studies were undertaken to assess the suitability of aluminium titanate (AT) and bismuth aluminate (BA) to remove fluoride ions from water.The effect of pH,dose of adsorbent,contact time,initial concentration,co-ions and temperature on fluoride removal efficiency were studied.The amounts of fluoride ions adsorbed,at 30℃ from 4 mg/L of fluoride ion solution,by AT and BA are 0.85 and 1.55 mg/g,respectively.The experimental data fitted well to the Freundlich and Langmuir isotherms.Thermodynamic parameters such as △H~0,△S~0 and △G~0 indicated that the removal of fluoride ions by AT is exothermic and non-spontaneous while that by BA is endothermic and spontaneous.Furrier transform infrared (FT-IR) analysis and X-ray diffraction (XRD) patterns of the adsorbent before and after adsorption indicated that fluoride ions are chemisorbed by these adsorbents.

Emissions of fluorides from welding processes.

Science.gov (United States)

Szewczyńska, Małgorzata; Pągowska, Emilia; Pyrzyńska, Krystyna

2015-11-01

The levels of fluoride airborne particulates emitted from welding processes were investigated. They were sampled with the patented IOM Sampler, developed by J. H. Vincent and D. Mark at the Institute of Occupational Medicine (IOM), personal inhalable sampler for simultaneous collection of the inhalable and respirable size fractions. Ion chromatography with conductometric detection was used for quantitative analysis. The efficiency of fluoride extraction from the cellulose filter of the IOM sampler was examined using the standard sample of urban air particle matter SRM-1648a. The best results for extraction were obtained when water and the anionic surfactant N-Cetyl-N-N-N-trimethylammonium bromide (CTAB) were used in an ultrasonic bath. The limits of detection and quantification for the whole procedure were 8μg/L and 24μg/L, respectively. The linear range of calibration was 0.01-10mg/L, which corresponds to 0.0001-0.1mg of fluorides per m(3) in collection of a 20L air sample. The concentration of fluorides in the respirable fraction of collected air samples was in the range of 0.20-1.82mg/m(3), while the inhalable fraction contained 0.23-1.96mg/m(3) of fluorides during an eight-hour working day in the welding room. Copyright © 2015. Published by Elsevier B.V.

Clinical Usefulness of 18F-fluoride Bone PET

International Nuclear Information System (INIS)

Kang, Ji Yeon; Lee, Won Woo; Lee, Byung Chul; Kim, Sang Eun; So, Young

2010-01-01

18 F-fluoride bone positron emission tomography (PET) has been reported as a useful bone imaging modality. However, no clinical bone PET study had been performed previously in Korea. The authors investigated the usefulness of 18 F-fluoride bone PET in Korean patients with malignant or benign bone disease. Eighteen consecutive patients (eight women, ten men; mean age, 55±12 years) who had undergone 18 F-fluoride bone PET for the evaluation of bone metastasis (n=13) or benign bone lesions (n=5) were included. The interpretation of bone lesions on 18 F-fluoride bone PET was determined by consensus of two nuclear medicine physicians, and final results were confirmed using combination of all imaging studies and/or clinical follow-up. The analysis was performed on the basis of lesion group. Thirteen patients with malignant disease had 15 lesion groups, among which seven were confirmed as metastatic bone lesions and eight were confirmed as non-metastatic lesions. 18 F-fluoride bone PET correctly identified six of seven metastatic lesions (sensitivity, 86%), and seven of eight non-metastatic lesions (specificity, 88%). On the other hand, five patients with benign conditions had five bone lesion groups; four were confirmed as benign bone diseases and the other one was confirmed as not a bone lesion. 18 F-fluoride bone PET showed correct results in all the five lesion groups. 18 F-fluoride bone PET showed promising potential for bone imaging in Korean patients with malignant diseases as well as with various benign bone conditions. Therefore, further studies are required on the diagnostic performance and cost-effectiveness of 18 F-fluoride bone PET.

Characteristics of selective fluoride adsorption by biocarbon-Mg/Al layered double hydroxides composites from protein solutions: kinetics and equilibrium isotherms study.