WorldWideScience

Sample records for thallium fluorides

  1. Fluoride

    Science.gov (United States)

    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 ...

  2. Extracorporeal treatment for thallium poisoning

    DEFF Research Database (Denmark)

    Ghannoum, Marc; Nolin, Thomas D; Goldfarb, David S

    2012-01-01

    The EXtracorporeal TReatments In Poisoning (EXTRIP) workgroup was formed to provide recommendations on the use of extracorporeal treatment (ECTR) in poisoning. To test and validate its methods, the workgroup reviewed data for thallium (Tl)....

  3. 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 ...

  4. Usefulness of Thallium Scan for Differential Diagnosis of Breast Mass

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Sang Kyun; Yum, Ha Yong; Lee, Chung Han; Choi, Kyung Hyun [Kosin University College of Medicine, Pusan (Korea, Republic of)

    1994-07-15

    The purpose of this study is to evaluate thallium scanning as a potential test in differentiating malignant from benign lesions of breast. Thirty-one female patients underwent thallium scan of the breast. After intravenous injection of 74-111 MBq(2-3 mCi)of thallium-201, anterior and lateral images were obtained. We compared thallium scans with pathological results. Of 11 patients with breast cancers, 10 cases (90.9%) were detected using thallium scan. Thallium scan obtained in one patient who had breast cancer but received several cycles of chemotherapy did not show thallium uptake. The smallest detectable cancer was 1.5 cm in diameter. In contrast, there is no thallium accumulation in breasts of 17 of 20 patients with benign disease (85%), Three cases of 13 fibrocystic disease show thallium uptake in their breast. In conclusion, thallium scan is an effective test in differentiating benign from malignant lesion.

  5. Thallium contamination of water in Canada

    Energy Technology Data Exchange (ETDEWEB)

    Cheam, V. [National Water Research Institute Branch, Burlington, ON (Canada). Aquatic Ecosystems Protection Research Branch

    2001-07-01

    A highly sensitive instrument, a Laser-Excited Atomic Fluorescence Spectrometer, has been developed to study thallium contamination in some important Canadian ecosystems from the Arctic (containing very low thallium concentration) to coal-related industries across Canada and even to the study of thallium toxicity in an invertebrate, Hyalella azteca. Overall, the data indicate that the coal power plants and mines contain higher thallium concentrations than the other ecosystems studied, and the eastern region has the highest Tl concentrations compared to other regions. The range of thallium concentration in ng/L for the Arctic snow and ice was between not detected and 8.4, for the Great Lakes waters 0.9 to 48, for pore waters 0.1 to 213, for western coal power plants and mines 0.1 to 1326, for central coal power plants 1.2 to 175, for eastern coal power plants and mines 0.2 to 23605, and for miscellaneous sites across Canada not detected to 4390 ng/L. Some of these high concentrations and those high ones reported in industrial wastewaters exceeded the chronic toxicity endpoints for Hyalella azteca mortality, growth and reproduction, and thus can cause serious distress to the environment. All data were integrated into a map of thallium distribution, the first one in Canada. Natural background level of thallium for the Arctic was estimated to be 0.02 to 0.03 pg/g.

  6. IRIS Toxicological Review of Thallium and Compounds ...

    Science.gov (United States)

    Thallium compounds are used in the semiconductor industry, the manufacture of optic lenses and low-melting glass, low-temperature thermometers, alloys, electronic devices, mercury lamps, fireworks, and imitation germs, and clinically as an imaging agent in the diagnosis of certain tumors. EPA's assessment of noncancer health effects and carcinogenic potential of thallium compounds was last prepared and added to the IRIS database between 1988 and 1990. The IRIS program is preparing an assessment that will incorporate current health effects information available for thallium and compounds, and current risk assessment methods. The IRIS assessment for thallium compounds will consist of a Toxicological Review and IRIS Summary. The Toxicological Review is a critical review of the physiochemical and toxicokinetic properties of a chemical, and its toxicity in humans and experimental systems. The assessment will present reference values for the noncancer effects of thallium compounds (RfD and Rfc), and a cancer assessment. The Toxicological Review and IRIS Summary have been subject to Agency review, Interagency review, and external scientific peer review. The final product will reflect the Agency opinion on the overall toxicity of thallium and compounds. EPA is undertaking an Integrated Risk Information System (IRIS) health assessment for thallium and compounds. IRIS is an EPA database containing Agency scientific positions on potential adverse human health effec

  7. Repeat thallium-201 SPECT in cerebral lymphoma.

    Science.gov (United States)

    Borggreve, F; Dierckx, R A; Crols, R; Mathijs, R; Appel, B; Vandevivere, J; Mariën, P; Martin, J J; De Deyn, P P

    1993-01-01

    The authors report on the contribution of Thallium-201 brain SPECT in the diagnosis and follow-up of a non-immunosuppressed patient, presenting with primary cerebral lymphoma. The tumoral process was at first not diagnosed on CT-scan, but Thallium-201 SPECT suggested a tumoral invasion. During corticosteroid treatment the tumor volume on CT-scan decreased, while on Thallium-201 SPECT there was an enhancement of the accumulation and an increasing tumor to non-tumor ratio. These scintigraphical findings more closely reflected the clinical course and the postmortem results.

  8. Thallium poisoning from maliciously contaminated food.

    Science.gov (United States)

    Meggs, W J; Hoffman, R S; Shih, R D; Weisman, R S; Goldfrank, L R

    1994-01-01

    Four young adults presented two days after one of them had received marzipan balls packaged in a box from an expensive candy manufacturer. Two ate one candy ball, while two others shared a third. The next day, variable gastrointestinal symptoms developed. On the third day, two patients developed painful paresthesiae of the hands and feet, an early but nonspecific clinical marker of thallium poisoning. A tentative diagnosis of thallium poisoning was made based on symptoms, and treatment was initiated. The remaining candies were radiographed. Metallic densities in the candies supported the diagnosis, and atomic absorption spectroscopy was used to quantitate thallium content. Each candy contained a potentially fatal dose. Five to seven days later, hypertension and tachycardia developed in the two patients who had ingested an entire candy. All patients developed alopecia but recovered without overt neurologic or other sequelae. While the diagnosis of thallium poisoning is often delayed until alopecia develops, an early diagnosis favors an effective treatment strategy.

  9. Thallium in mineral resources extracted in Poland

    Directory of Open Access Journals (Sweden)

    Bojakowska I.

    2013-04-01

    Full Text Available Thallium concentrations in primary mineral commodities extracted in Poland and processed in high temperatures were determined by ICP-MS method. Samples of hard and brown coal, copper-silver and zinclead ores, argillaceous and calcareous rocks of different genesis and age were analyzed. The highest thallium concentrations occur in the zinc-lead ores, the average content being of 52.1 mg/kg. The copper ores contain in average 1.4 mg/kg of thallium. Hard coals from the Upper Silesian Coal Basin display higher thallium content than those exploited in the Lublin Coal Basin. Brown coals from Turow deposit distinguish by much higher values, 0.7 mg/kg Tl, than those from huge Bełchatów and smaller Konin-Turek region deposits. Average thallium concentrations in clays used for ceramic materials are lower than 1 mg/kg, except of Mio-Pliocene Slowiany deposit. The average content of thallium in the studied limestone and dolomite raw materials for cement, lime, and metallurgical flux, and refractories is very low in comparison to the average amounts in the world carbonate rocks.

  10. Examining of Thallium in Cigarette Smokers.

    Science.gov (United States)

    Ghaderi, Amir; NasehGhafoori, Payam; Rasouli-Azad, Morad; Sehat, Mojtaba; Mehrzad, Fateme; Nekuei, Mina; Aaseth, Jan; Banafshe, Hamid Reza; Mehrpour, Omid

    2017-08-01

    Smoking is one of the sources of thallium which is considered as a toxic heavy metal. The aim of this study was to determine urinary thallium levels and related variables in smokers, compared to a control group. The study was conducted on 56 participants who had smoked continuously during the year before they were referred to Kashan Smoking Cessation Clinic. Fifty-three nonsmokers who were family members or friends of the smokers were selected as the control group. Urinary thallium was measured in both groups (n = 109) using atomic absorption spectrophotometry. The mean value (with SD) for urinary thallium in the smokers (10.16 ± 1.82 μg/L) was significantly higher than in the control group (2.39 ± 0.63 μg/L). There was a significant relationship between smoking duration and urinary thallium levels (P = 0.003). In a subgroup of smokers who was addicted to opium and opium residues (n = 9), the mean level of thallium (37.5 ± 13.09 μg/L) was significantly higher than in the other smokers (4.93 ± 4.45; P = 0.001). Multiple regression analysis showed opioid abuse, insomnia, and chronic obstructive pulmonary disease (COPD), together were strong predictors of urinary thallium levels in smokers. There was no significant difference in thallium level in hookah smokers (P = 0.299) or in those with COPD compared to other smokers (P = 0.375). Urinary thallium levels of smokers with clinical signs of depression, sleep disorders, memory loss, and sweating were higher than those of smokers without these signs. Since thallium, as other toxic metals is accumulated in the body, and cigarette smoking also involves carcinogenic exposures and health hazards for passively exposed people, the need for cigarette control policies is emphasized.

  11. Thallium-201 scintigraphy in unstable angina pectoris

    Energy Technology Data Exchange (ETDEWEB)

    Wackers, F.J.T.; Lie, K.I.; Liem, K.L.; Sokole, E.B.; Samson, G.; Van Der Schoot, J.B.; Durrer, D.

    1978-04-01

    Thallium-201 scintigraphy was performed during the pain free period in 98 patients with unstable angina. Scintiscans were positive in 39 patients, questionable in 27 patients and normal in 32 patients. Eighty-one patients responded favorably to treatment (group I). Seventeen patients had complicated courses (group II) and despite maximal treatment with propranolol either developed infarction (six patients) or continued to have angina necessitating coronary surgery (11 patients). In group I during the pain free period 26 of 81 patients had positive thallium-201 scans, whereas 20 patients had an abnormal ECG at that time; during angina 18 patients had transient ECG changes. In group II during the pain free period 13 of 17 patients had positive scans, whereas two patients had abnormal ECG at that time; during angina 12 patients showed transient ECG changes. The sensitivity to recognize group II was 76% for thallium-201 scintigraphy, 11% for ECG during the pain free period; 70% for ECG during angina; 94% for the combination of either positive scans or abnormal ECG. Thus, positive thallium-201 scans occur in patients with unstable angina, positive scans can be obtained during the pain free period, thallium-201 scans are more frequently positive in patients with complicated course.

  12. Thallium-201 uptake in a benign thymoma

    Energy Technology Data Exchange (ETDEWEB)

    Campeau, R.J.; Ey, E.H.; Varma, D.G.

    1986-07-01

    A 68-year-old woman was admitted with atypical angina. A chest radiograph showed an anterior mediastinal mass that was confirmed on CT. The mass was relatively avascular and separate from the heart and great vessels. She underwent stress thallium testing that demonstrated no exercise-induced ischemia; however, an abnormal focus of thallium activity was present in the anterior mediastinum on stress and redistribution images. Cardiac catheterization demonstrated a normal left ventriculogram, coronary arteries and thoracic aorta. Subsequent surgery and pathologic examination revealed the mass to be a benign thymoma arising in the right lobe of the thymus gland.

  13. Endogenous thiols enhance thallium toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Montes, Sergio; Rios, Camilo [Instituto Nacional de Neurologia y Neurocirugia, ' ' Manuel Velasco Suarez' ' , Departamento de Neuroquimica, Mexico, D.F (Mexico); Soriano, Luz; Monroy-Noyola, Antonio [Universidad Autonoma del Estado de Morelos, Laboratorio de Neuroproteccion, Facultad de Farmacia, Cuernavaca, Morelos (Mexico)

    2007-10-15

    Either L-methionine (L-met) or L-cysteine (L-cys), given alone and in combination with Prussian blue (PB) was characterized as treatment against acute thallium (Tl) toxicity in rats. Animals were intoxicated with 32 mg/kg Tl acetate corresponding to rat LD{sub 50}. Antidotal treatments were administered during 4 days, as follows: (1) vehicle, (2) L-met 100 mg/kg i.p. twice a day, (3) L-cys 100 mg/kg i.p. twice a day, (4) PB 50 mg/kg oral, twice a day, (5) L-met + PB and (6) L-cys + PB. Mortality was as follows: control 50%; L-met 80%; L-cys 80%; PB 20%; L-met + PB 90% and L-cys + PB 100%. In a different experiment, using 16 mg/kg of Tl, tissue levels of this metal were analyzed. PB treatment statistically diminished Tl content in body organs and brain regions (P < 0.01). Whereas, separate treatments of L-met and L-cys failed to decrease Tl content in organs and brain regions; while its administration in combination with PB (L-met + PB and L-cys + PB groups) lowered Tl levels in body organs in the same extent as PB group. Results indicate that L-met and L-cys administered alone or in combination with PB should not be considered suitable treatments against acute Tl toxic effects because this strategy failed to prevent mortality and Tl accumulation in brain. (orig.)

  14. Thallium in fractions of soil formed on floodplain terraces.

    Science.gov (United States)

    Jakubowska, Monika; Pasieczna, Anna; Zembrzuski, Wlodzimierz; Swit, Zbigniew; Lukaszewski, Zenon

    2007-01-01

    Two soils formed on the floodplain terrace of a rivulet flowing through the zinc-lead ore exploration area polluted with thallium and one soil from a floodplain terrace of the reference area were investigated in terms of thallium distribution between soil fractions. Such type of soil is formed on river floodplain terraces next to the main river channel and its composition records the history of river pollution. A sequential extraction of soil according to the BCR protocol was performed with an additional initial stage of extraction with water. Apart from labile thallium, thallium entrapped in the residual parent matter was also determined. Thallium was determined by flow-injection differential-pulse anodic stripping voltammetry. In all three cases, the major fraction is thallium entrapped in parent matter. Top soil from the polluted area contains 49.3% thallium entrapped in the residual parent matter, the bottom soil contains 41% while the reference soil contains 80% in this fraction. The major part of labile thallium is located in the reducible fraction (27.7% of total thallium in the top soil, 27% in the bottom soil and 12.4% of the reference soil). Second in terms of significance is the fraction of oxidizable thallium. The top soil contains 12% of total thallium concentration, the bottom soil contains 19% of total concentration, while the reference soil contains 4.1% of total concentration. The acid soluble/exchangeable fraction of thallium has almost the same significance as the oxidizable fraction. The top soil contains 10.4% of the total concentration, while the bottom soil contains 12% of the total concentration. Water soluble thallium concentration is very small. Comparison of the top and the bottom soil show that thallium has not been transported from the river channel onto the floodplain terrace over a long period.

  15. Characteristics of photoconductivity in thallium monosulfide single ...

    Indian Academy of Sciences (India)

    journal of. March 2007 physics pp. 467–479. Characteristics of photoconductivity in thallium monosulfide single crystals. I M ASHRAF, H A ELSHAIKH and A M BADR. Physics Department ... pendencies of carrier lifetime on light intensity, applied voltage and temperature are also ..... 14, 797 (1935) (in Japanese). [10] A T ...

  16. Story of Fluoridation

    Science.gov (United States)

    ... Fluoride > The Story of Fluoridation The Story of Fluoridation Main Content It started as an observation, that ... fluoridate its drinking water.The Grand Rapids water fluoridation study was originally sponsored by the U.S. Surgeon ...

  17. Extraction separation of thallium (III) from thallium (I) with n-octylaniline.

    Science.gov (United States)

    Shilimkar, Tulshidas N; Anuse, Mansing A; Patil, Kesharsingh J

    2002-01-01

    A novel method is developed for the extraction separation of thallium(III) from salicylate medium with n-octylaniline dissolved in toluene as an extractant. The optimum conditions have been determined by making a critical study of weak acid concentration, extractant concentration, period of equilibration and effect of solvent on the equilibria. The thallium (III) from the pregnant organic phase is stripped with acetate buffer solution (pH 4.7) and determined complexometrically with EDTA. The method affords the sequential separation of thallium(III) from thallium(I) and also commonly associated metal ions such as Al(III), Ga(III), In(III), Fe(III), Bi(III), Sb(III) and Pb(II). It is used for analysis of synthetic mixtures of associated metal ions and alloys. The method is highly selective, simple and reproducible. The reaction takes place at room temperature and requires 15-20 min for extraction and determination of thallium(III).

  18. Thallium bromide iodide crystal acoustic anisotropy examination.

    Science.gov (United States)

    Mantsevich, S N

    2017-03-01

    Thallium bromide iodide crystal also known as KRS-5 is the well known material used in far infrared radiation applications for optical windows and lenses fabrication. The main advantage of this material is the transparency in wide band of wavelengths from 0.53 to 50μm. Despite such advantages as transparency and large acousto-optic figure of merit values, KRS-5 is rarely used in acousto-optics. Nevertheless this material seems to be promising for far infrared acousto-optic applications. The acoustic and acousto-optic properties of KRS-5 needed for the full use in optoelectronics are not well understood to date. In this paper the detailed examination of thallium bromide iodide crystal acoustic properties is presented. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Fluoridation Basics

    Science.gov (United States)

    ... Dental Health Care Settings Single-Use (Disposable) Devices Sterilization Cleaning Monitoring Packaging & Storage Use & Handling of Toothbrushes ... Less pain and suffering because of tooth decay. History of Fluoride in Water In the 1930s, scientists ...

  20. Thallium and its contents in Remata carbonate rocks

    Directory of Open Access Journals (Sweden)

    Kondelová Marcela

    1996-09-01

    Full Text Available The article presents at first the list of thallium own minerals and its isomorphic content in other minerals, especially in Slovakian ore deposits. This trace element was found in numerous dolomite-rock samples from Remata massif near Handlová. An interesting level of Tl content was analyzed in nonsilicified rocks; the highest content of Tl (and Ag are along the E – W line of disturbance. The presence of thallium in some limonitic aggregates in close Kremnica-gold deposit indicate any continuous relation. Some similarities to type gold deposits Carlin ( USA are discussed, even if no gold and discrete thallium phases were in Remata determined yet.

  1. Bottled Water and Fluoride

    Science.gov (United States)

    ... What's this? Submit What's this? Submit Button Bottled Water Recommend on Facebook Tweet Share Compartir Consumers drink ... questions about bottled water and fluoride. Does bottled water contain fluoride? Bottled water products may contain fluoride, ...

  2. [Enamel fluoride uptake following fluoride application and fluoride precipitation].

    Science.gov (United States)

    Buchalla, Wolfgang; Lennon, Aine M; Trage, Katrin; Becker, Klaus; Attin, Thomas

    2007-01-01

    This study is on fluoride uptake into enamel following fluoride precipitation with calcium hydroxide. Five specimens each from 12 bovine incisors were polished, covered with a salivary pellicle, and distributed into five groups (n=12). A fluoride solution (43,500 ppm F from magnesiumfluorosilicate, copper-(II)-fluorosilicate and sodium-fluoride, pH 2; Tiefenfluorid Touchierlösung, Humanchemie) and Ca(OH)2-solution (Tiefenfluorid Nachtouchierlösung) were applied subsequently in group TN. "Touchierlosung" only was used in group T, sodium-fluoride (43,500 ppm F, pH 2) in group NaF, and aminefluoride (Elmex fluid, 10,000 ppm F, pH 4) in group EF. No fluoride was used in group NK (negative control). Following rinsing and 24 h storage in artificial saliva surface KOH-soluble fluoride content (KOHF), and structurally bound fluoride content (SBF) from three layers (0-33, 33-66 and 66-99 pm) was determined by fluoride electrode procedures. KOHF (median in microg/cm2) of NK was below the lower limit of quantification of the fluoride electrode. The other group values were significantly higher (Mann-Whitney test, p precipitation reaction with Ca(OH)2 following fluoridation did not increase enamel fluoride uptake.

  3. Tracing thallium contamination in soils using isotopes

    Science.gov (United States)

    Vaněk, Aleš; Grösslová, Zuzana; Mihaljevič, Martin; Ettler, Vojtěch; Trubač, Jakub; Teper, Leslaw; Cabala, Jerzy; Rohovec, Jan; Penížek, Vít; Zádorová, Tereza; Pavlů, Lenka; Holubík, Ondřej; Drábek, Ondřej; Němeček, Karel; Houška, Jakub; Ash, Christopher

    2017-04-01

    We report the thallium (Tl) isotope record in moderately contaminated soils, which have been historically affected by emissions from coal-fired power plants. Our findings clearly demonstrate that Tl of anthropogenic (high-temperature) origin with light isotope composition was deposited onto the studied soils, where heavier Tl (ɛ205Tl -1) naturally occurs. The results show a positive linear relationship (R2 = 0.71) between 1/Tl and the isotope record, as determined for all the soils and bedrocks, also indicative of binary Tl mixing between two dominant reservoirs. We also identified significant Tl isotope variations within the products from coal combustion and thermo-desorption experiments with local Tl-rich coal pyrite. Bottom ash exhibited the heaviest Tl isotope composition (ɛ205Tl 0), followed by fly ash (ɛ205Tl between -2.5 and -2.8) and volatile Tl fractions (ɛ205Tl between -6.2 and -10.3), suggesting partial Tl isotope fractionations. Despite the evident role of soil processes in the isotope redistribution, we demonstrate that Tl contamination can be traced in soils, and propose that the isotope data represent a possible tool to aid our understanding of post-depositional Tl dynamics in surface environments for the future. This research was supported by the Czech Science Foundation (grant no. 14-01866S and 17-03211S).

  4. Fluoride and Dental Health

    OpenAIRE

    Nikiforuk, Gordon

    1988-01-01

    Studies conducted under the widest variety of controlled conditions attest to the safety, efficacy, and cost benefits of fluoridation. A program that combines the use of systemic and topical fluoride results in maximum benefits. The author of this article reviews the metabolism of fluoride and its mechanism of action, and discusses practical modes of employing fluoride in caries prevention with special emphasis on the use of fluoride supplements for infants and young children in areas of non-...

  5. Catalytic properties of Thallium-containing mesoporous silicas

    Directory of Open Access Journals (Sweden)

    A. Baradji

    2017-02-01

    Full Text Available The benzylation of benzene by benzyl chloride over a series of Thallium-containing mesoporous silicas with different Tl contents has been investigated. These materials (Tl-HMS-n have been characterized by chemical analysis, N2 adsorption/desorption isotherm and X-ray diffraction (XRD. The mesoporous Thallium-containing materials showed both high activity and high selectivity for the benzylation of benzene. More interesting is the observation that these catalysts are always active and selective for large molecules like naphthenic compounds such as methoxynaphthalene.

  6. A comparison of the clinical relevance of thallium201 and ...

    African Journals Online (AJOL)

    Thallium-201 is at present the radiotracer of choice for the clinical evaluation of myocardial blood flow. Although different technetium-99m-isonitrile agents have been synthesised recently, only 99mTc-melhoxyisobutyl-isonitrile (99mTc_MIBI) has proved to hold promise for clinical implementation. The myocardial distribution ...

  7. Een bepalingsmethode voor thallium in regenwater met behulp van voltammetrie

    NARCIS (Netherlands)

    Struijs; J.; Wolfs; P.M.; Esseveld; F.G.van

    1985-01-01

    In dit rapport wordt een bepalingmethode beschreven voor thallium in het nanogram/liter-gebied, waarbij gebruik wordt gemaakt van differentiele pulse-anodic stripping voltammetry (DPASV) aan de dunne kwikfilm. Met deze techniek blijkt het mogelijk om de concentratie van dit element rechtstreeks

  8. IRIS Toxicological Review of Thallium and Compounds (External Review Draft)

    Science.gov (United States)

    Thallium compounds are used in the semiconductor industry, the manufacture of optic lenses and low-melting glass, low-temperature thermometers, alloys, electronic devices, mercury lamps, fireworks, and imitation germs, and clinically as an imaging agent in the diagnosis of certai...

  9. Band-Structure of Thallium by the LMTO Method

    DEFF Research Database (Denmark)

    Holtham, P. M.; Jan, J. P.; Skriver, Hans Lomholt

    1977-01-01

    The relativistic band structure of thallium has been calculated using the linear muffin-tin orbital (LMTO) method. The positions and extents of the bands were found to follow the Wigner-Seitz rule approximately, and the origin of the dispersion of the bands was established from the canonical s...

  10. A Simple and Rapid Complexometric Determination of Thallium(III ...

    African Journals Online (AJOL)

    A simple, rapid and selective complexometric method is proposed for the determination of thallium(III), using mercaptoethane(EtSH) as demasking agent. The sample solution containing Tl(III) is first complexed with excess EDTA and the surplus EDTA is removed by titration at pH 5–6 with zinc sulphate solution using ...

  11. Hair as Biomarker of Fluoride Exposure in a Fluoride Endemic Area and a Low Fluoridated Area

    OpenAIRE

    Parimi, Nalini; Viswanath, V; Kashyap, Bina; Patil, Pavan Uday

    2013-01-01

    Aim: The aim of the present study was to determine whether hair could be used as biomarker of fluoride exposure. Materials and Methods: The study was carried out on 30 people living in an endemically fluoridated area and a low fluoridated area. Samples of hair from the occipital were taken and subjected to fluoride analysis by a fluoride ion electrode. Results: Lower fluoride levels in water supplies correlated with lower levels of fluoride in hair and more over higher fluoride levels in wate...

  12. 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 ...

  13. Selective Thallium (I Ion Sensor Based on Functionalised ZnO Nanorods

    Directory of Open Access Journals (Sweden)

    Z. H. Ibupoto

    2012-01-01

    Full Text Available Well controlled in length and highly aligned ZnO nanorods were grown on the gold-coated glass substrate by hydrothermal growth method. ZnO nanorods were functionalised with selective thallium (I ion ionophore dibenzyldiaza-18-crown-6 (DBzDA18C6. The thallium ion sensor showed wide linear potentiometric response to thallium (I ion concentrations ( M to  M with high sensitivity of 36.87 ± 1.49 mV/decade. Moreover, thallium (I ion demonstrated fast response time of less than 5 s, high selectivity, reproducibility, storage stability, and negligible response to common interferents. The proposed thallium (I ion-sensor electrode was also used as an indicator electrode in the potentiometric titration, and it has shown good stoichiometric response for the determination of thallium (I ion.

  14. 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

  15. A Simple and Rapid Complexometric Determination of Thallium(III ...

    African Journals Online (AJOL)

    NJD

    2005-10-08

    Oct 8, 2005 ... surplus EDTA is removed by titration at pH 5–6 with zinc sulphate solution using xylenol orange as indicator. ... Reproducible and accurate results are obtained in the concentration range 4–80 mg of thallium with a relative error ≤ ±0.6% .... soluble and stable 1:1 complex with Tl(I) so formed.22 This was.

  16. Thallium in the hydrosphere of south west England

    Energy Technology Data Exchange (ETDEWEB)

    Law, Sin [School of Geography, Earth and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Turner, Andrew, E-mail: aturner@plymouth.ac.uk [School of Geography, Earth and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)

    2011-12-15

    Thallium is a highly toxic metal whose environmental concentrations, distributions and behaviour are not well understood. In the present study we measure the concentrations of Tl in filtered and unfiltered samples of rain, tap, river, estuarine and waste waters collected from south west England. Dissolved Tl was lowest (<20 ng L{sup -1}) in tap water, rain water, treated sewage and landfill effluents, estuarine waters, and rivers draining catchments of sandstones and shales. Concentrations up to about 450 ng L{sup -1} were observed in rivers whose catchments are partly mineralized and where metal mining was historically important, and the highest concentration ({approx}1400 ng L{sup -1}) was measured in water abstracted directly from an abandoned mine. Compared with other trace metals measured (e.g. As, Cd, Co, Cr, Cu, Ni, Pb, Zn), Tl has a low affinity for suspended particles and undergoes little removal by conventional (hydroxide precipitation) treatment of mine water. - Highlights: > Thallium concentrations have been measured in natural and waste waters from south west England. > Dissolved concentrations spanned three orders of magnitude and were highest in water from an abandoned mine. > Inputs associated with historical metal mine workings are the most important to the regional hydrosphere. - Concentrations of dissolved thallium in waters of south west England span two orders of magnitude and are greatest in water from an abandoned mine.

  17. Fluorides and non-fluoride remineralization systems

    NARCIS (Netherlands)

    Amaechi, B.T.; van Loveren, C.

    2013-01-01

    Caries develops when the equilibrium between de- and remineralization is unbalanced favoring demineralization. De- and remineralization occur depending on the degree of saturation of the interstitial fluids with respect to the tooth mineral. This equilibrium is positively influenced when fluoride,

  18. 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.

  19. Sodium dithionite as a selective demasking agent for the complexometric determination of thallium

    Directory of Open Access Journals (Sweden)

    PRAKASH SHETTY

    2005-11-01

    Full Text Available Sodium dithionite is proposed as a new demasking agent for the rapid and selective complexometric determination of thallium(III. In the presence of diverse metal ions, thallium (III was first complexed with excess EDTA and the surplus EDTAwas then titrated with a standard zinc sulphate solution at pH 5–6 (hexamine buffer using Xylenol Orange as the indicator. The EDTAequivalent to thallium was then released selectively with sodium dithionite and back titrated with a standard zinc sulphate solution as before. Reproducible and accurate results were obtained in the range 4–100 mg of thallium with a relative error of ±27 % and a coefficient of variation (n = 6 of not more than 0.30 %. The effects of various diverse ions were studied. The method was applied to the determination of thallium in its complexes and in alloys.

  20. Fluorides and non-fluoride remineralization systems.

    Science.gov (United States)

    Amaechi, Bennett T; van Loveren, Cor

    2013-01-01

    Caries develops when the equilibrium between de- and remineralization is unbalanced favoring demineralization. De- and remineralization occur depending on the degree of saturation of the interstitial fluids with respect to the tooth mineral. This equilibrium is positively influenced when fluoride, calcium and phosphate ions are added favoring remineralization. In addition, when fluoride is present, it will be incorporated into the newly formed mineral which is then less soluble. Toothpastes may contain fluoride and calcium ions separately or together in various compounds (remineralization systems) and may therefore reduce demineralization and promote remineralization. Formulating all these compounds in one paste may be challenging due to possible premature calcium-fluoride interactions and the low solubility of CaF2. There is a large amount of clinical evidence supporting the potent caries preventive effect of fluoride toothpastes indisputably. The amount of clinical evidence of the effectiveness of the other remineralization systems is far less convincing. Evidence is lacking for head to head comparisons of the various remineralization systems. Copyright © 2013 S. Karger AG, Basel.

  1. How Does Fluoride Work?

    Science.gov (United States)

    ... A Movies & More Quizzes Kids' Dictionary of Medical Words En Español What Other Kids Are Reading How Does Fluoride Work? Is ... There's fluoride in your toothpaste and even in your water. But how does it work to keep teeth ...

  2. Other Fluoride Products

    Science.gov (United States)

    ... Health Basics Children’s Oral Health Protecting Your Child’s Teeth Brush Up on Healthy Teeth Adult Oral Health Oral Health for Older Americans ... benefit to persons not at high risk for tooth decay, especially those who drink ... with fluoride toothpaste. Fluoride Varnish Form Varnishes ...

  3. [Efficiency of hemoperfusion on clearing thallium based on atomic absorption spectrometry].

    Science.gov (United States)

    Tian, Tian; Wang, Yongan; Nie, Zhiyong; Wang, Jiao; Peng, Xiaobo; Yuan, Ye; Li, Wanhua; Qiu, Zewu; Xue, Yanping; Xiong, Yiru

    2015-04-01

    To determine thallium in whole blood by atomic absorption detection method, and to investigate the eliminating effect of hemoperfusion (HP) for thallium in blood. The blood of Beagle dogs which had not exposed to thallium before were obtained for preparation of thallium nitrate ( TlNO3 )-containing solution in three concentrations according to the conversion formula based on animal weight and volume of blood. HP was performed in the simulated in vivo environment. The content of TlNO3 in blood of the next group was determined on the amount of TlNO3 for the last HP of the former dose group. Thallium quantity in different samples was measured with atomic absorption spectrometer blood samples before and after HP. Finally, the thallium concentration in blood was analyzed statistically. Thallium concentrations showed a good linear relationship in the range of 0-200 μg/L (r = 0.998 4). The intra-day precision (RSD) was lower than 4.913%, the intra-day recovery rate was 96.2%-111.9%; the inter-day precision (RSD) was lower than 7.502%, the inter-day recovery rate was 89.6%-105.2%. The concentration of thallium in blood was significantly reduced after HP per time in high, middle, and low dose groups [(453.43 ± 27.80) mg/L to (56.09 ± 14.44) mg/L in high dose group, F = 8.820, P = 0.003; (64.51 ± 13.60) mg/L to (3.19 ± 0.23) mg/L in middle dose group, F = 36.312, P = 0.000; (5.40 ± 0.98) mg/L to (0.38 ± 0.25) mg/L in low dose group, F = 46.240, P = 0.000 ]. The adsorption rate of four times of HP in high, middle and low dose group were (87.63 ± 2.48 )%, (95.06 ± 1.54 )% and (92.76 ± 4.87)%, respectively, without significant difference (F = 4.231, P = 0.070). The method for measuring thallium was established, and it shows a very stable, simple, sensitive for determination of thallium. HP can effectively remove thallium from blood. Thallium concentration can be reduced by 90% after four times of HP. HP is also effective even when thallium concentration is not high.

  4. 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...... week (FMR). All children received oral hygiene instructions and comprehensive dental care at the local Public Dental Clinics throughout the study period. MAIN OUTCOME MEASURES: Increment of caries lesions in permanent teeth at both cavitated and initial caries levels. RESULTS: The groups were balanced...

  5. 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

  6. Left ventricular dilatation and pulmonary thallium uptake after single-photon emission computer tomography using thallium-201 during adenosine-induced coronary hyperemia

    Energy Technology Data Exchange (ETDEWEB)

    Iskandrian, A.S.; Heo, J.; Nguyen, T.; Lyons, E.; Paugh, E. (Philadelphia Heart Institute, PA (USA))

    1990-10-01

    This study examined the implications of left ventricular (LV) dilatation and increased pulmonary thallium uptake during adenosine-induced coronary hyperemia. The lung-to-heart thallium ratio in the initial images was significantly higher in patients with coronary artery disease (CAD) than normal subjects; 0.48 +/- 0.16 in 3-vessel disease (n = 16), 0.43 +/- 0.10 in 2-vessel disease (n = 20), 0.43 +/- 0.08 in 1-vessel disease (n = 16) and 0.36 +/- 0.05 in normal subjects (n = 7) (p less than 0.001, 0.09 and 0.06, respectively). There was a significant correlation between the severity and the extent of the perfusion abnormality (determined from the polar maps) and the lung-to-heart thallium ratio (r = 0.51 and 0.52, respectively, p less than 0.0002). There was also a significant correlation between lung thallium washout and lung-to-heart thallium ratio (r = 0.42, p = 0.0009) and peak heart rate (r = -0.49, p less than 0.0001). The LV dilatation was mostly due to an increase in cavity dimension (30% increase) and to a lesser extent (6% increase) due to increase in LV size. (The cavity dimensions were measured from the short-axis slices at the midventricular level in the initial and delayed images). The dilation was seen in patients with CAD but not in the normal subjects. These changes correlated with the extent and severity of the thallium perfusion abnormality. Thus, adenosine-induced coronary hyperemia may cause LV dilation and increased lung thallium uptake on the basis of subendocardial ischemia.

  7. Early detection of restenosis after successful percutaneous transluminal coronary angioplasty by exercise-redistribution Thallium scintigraphy

    NARCIS (Netherlands)

    W. Wijns (William); P.W.J.C. Serruys (Patrick); J.H.C. Reiber (Johan); P.J. de Feyter (Pim); M.J.B.M. van den Brand (Marcel); M.L. Simoons (Maarten); P.G. Hugenholtz (Paul)

    1985-01-01

    textabstractThe value of exercise testing and thallium scintigraphy in predicting recurrence of angina pectoris and restenosis after a primary successful transluminal coronary angioplasty (PTCA) was prospectively evaluated. In 89 patients, a symptom-limited exercise electrocardiogram (ECG) and

  8. 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...

  9. Oral zinc sulphate in treatment of patients with thallium poisoning: A clinical therapeutic trial

    Directory of Open Access Journals (Sweden)

    Ahmed A. Al-Mohammadi

    2011-06-01

    Full Text Available Thallium poisoning is usually associated with typical dermatological features simulating that of zinc deficiency. The aim of this study was to evaluate the role of oral zinc sulphate in the treatment of patients with thallium poisoning.Materials and methods: This clinical therapeutic trial study was conducted in Departments of Dermatology of Baghdad and Basrah Teaching Hospitals from February 2008 - February 2010, where a total of 37 patients with thallium poisoning were enrolled.A detailed history was taken from all patients and complete clinical examination was performed. All patients received zinc sulphate in a dose of 5 mg/kg three times a day few days before confirming the diagnosis of thallium poisoning. Thallium in urine had been measured using the colorimetric method and was positive in all patients. After confirming the diagnosis of thallium poisoning, thallium antidotes Prussian blue was given to 32 patients.Results: Age range of 37 patients was 5-33 (24±5.3 years. The dermatological findings were mainly: anagen hair loss affected the scalp and limbs. Also, dusky ecchymotic red dermatitis like rash was observed on the face and dorsum of hands and legs, while neurological manifestations were mainly of peripheral neuropathy, were reported in 21 (55% patients. All patients but two responded promptly to a trial of zinc sulphate within few days.Conclusion: Oral Zinc sulphate appears to be an effective and safe treatment for thallium poisoning particularly for skin and hair features and in reducing its lethal progression and complications. J Clin Exp Invest 2011;2(2:133-7

  10. Fate of Thallium(I) in Reverse Osmosis and Chlorinated Water Matrices

    Science.gov (United States)

    2014-02-01

    THALLIUM(I) IN REVERSE OSMOSIS AND CHLORINATED WATER MATRICES ECBC-TR-1127 Approved for public release; distribution is unlimited...3. DATES COVERED (From - To) Apr 2010 - Dec 2011 4. TITLE AND SUBTITLE Fate of Thallium(I) in Reverse Osmosis and Chlorinated Water Matrices... osmosis (RO) and RO water with added chlorine (RO-Cl) was measured using inductively coupled plasma optical emission spectroscopy (ICP-OES) for a period of

  11. 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...

  12. 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...

  13. Thallium in the hydrosphere of south west England.

    Science.gov (United States)

    Law, Sin; Turner, Andrew

    2011-12-01

    Thallium is a highly toxic metal whose environmental concentrations, distributions and behaviour are not well understood. In the present study we measure the concentrations of Tl in filtered and unfiltered samples of rain, tap, river, estuarine and waste waters collected from south west England. Dissolved Tl was lowest (<20 ng L(-1)) in tap water, rain water, treated sewage and landfill effluents, estuarine waters, and rivers draining catchments of sandstones and shales. Concentrations up to about 450 ng L(-1) were observed in rivers whose catchments are partly mineralized and where metal mining was historically important, and the highest concentration (~1400 ng L(-1)) was measured in water abstracted directly from an abandoned mine. Compared with other trace metals measured (e.g. As, Cd, Co, Cr, Cu, Ni, Pb, Zn), Tl has a low affinity for suspended particles and undergoes little removal by conventional (hydroxide precipitation) treatment of mine water. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Qualitative evaluation of coronary flow during anesthetic induction using thallium-201 perfusion scans

    Energy Technology Data Exchange (ETDEWEB)

    Kleinman, B.; Henkin, R.E.; Glisson, S.N.; el-Etr, A.A.; Bakhos, M.; Sullivan, H.J.; Montoya, A.; Pifarre, R.

    1986-02-01

    Qualitative distribution of coronary flow using thallium-201 perfusion scans immediately postintubation was studied in 22 patients scheduled for elective coronary artery bypass surgery. Ten patients received a thiopental (4 mg/kg) and halothane induction. Twelve patients received a fentanyl (100 micrograms/kg) induction. Baseline thallium-201 perfusion scans were performed 24 h prior to surgery. These scans were compared with the scans performed postintubation. A thallium-positive scan was accepted as evidence of relative hypoperfusion. Baseline hemodynamic and ECG data were obtained prior to induction of anesthesia. These data were compared with the data obtained postintubation. Ten patients developed postintubation thallium-perfusion scan defects (thallium-positive scan), even though there was no statistical difference between their baseline hemodynamics and hemodynamics at the time of intubation. There was no difference in the incidence of thallium-positive scans between those patients anesthetized by fentanyl and those patients anesthetized with thiopental-halothane. The authors conclude that relative hypoperfusion, and possibly ischemia, occurred in 45% of patients studied, despite stable hemodynamics, and that the incidence of these events was the same with two different anesthetic techniques.

  15. Studies on fluoridated toothpicks.

    Science.gov (United States)

    Kashani, H

    1998-01-01

    The aim of this thesis was to evaluate the wooden toothpick as a vehicle for the delivery of fluoride to the approximal area. After two minutes use in vivo, the release of fluoride from the pointed section of a toothpick impregnated in 4% NaF was estimated to 0.15 mg. Toothpicks produced similar or somewhat higher fluoride concentrations in the approximal area compared with other fluoride-containing products, like dentifrice, mouthrinse solution and tablet. The mean fluoride concentration in an approximal area treated for two minutes with a toothpick impregnated in 4% NaF was around 11 mM/l. Toothpicks impregnated in 4% NaF, 8% SnF2 or 2% chlorhexidine had an effect on the proportion of mutans streptococci and on the decline of pH in dental plaque, but it was small and only of short duration. The recolonization of mutans streptococci was, however, slower after using the SnF2- and chlorhexidine-impregnated toothpicks than after using the NaF- and non-impregnated toothpicks. The effect of fluoridated toothpicks on the degree of de- and remineralization of enamel and dentine was measured using transversal microradiography in an in situ study. Four weeks' use of toothpicks, especially of NaF-impregnated toothpicks, reduced the degree of demineralization of enamel and dentine at approximal sites. Secondary ion mass spectrometry was also used to determine the fluoride content in the outer surface of dentine, which increased more than 10 times after using fluoride toothpicks compared with non-impregnated toothpicks. In a second in situ study, 4% NaF-, 2% chlorhexidine- and non-impregnated toothpicks had a similar effect on sound and demineralized enamel and on demineralized dentine. However, the NaF toothpicks were superior in terms of their effect on sound dentine. The effect on mutans streptococci and plaque-pH, on the other hand, was the same for all three types of toothpicks. The main conclusion from this thesis is that the wooden toothpick is a suitable vehicle for

  16. Private Well Water and Fluoride

    Science.gov (United States)

    ... fluoride, such as drinking water at school or daycare, and fluoride toothpaste. It is not currently feasible ... 2015 Content source: Division of Oral Health , National Center for Chronic Disease Prevention and Health Promotion Email ...

  17. Prediction for new magnetoelectric fluorides

    NARCIS (Netherlands)

    Nenert, G.; Palstra, T. T. M.

    2007-01-01

    We use symmetry considerations in order to predict new magnetoelectric fluorides. In addition to these magnetoelectric properties, we discuss which among these fluorides are the ones susceptible to present multiferroic properties. We emphasize that several materials exhibit ferromagnetic properties.

  18. 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

  19. 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 an el...... brushing with fluoride toothpaste....

  20. Magnetic interactions through fluoride

    DEFF Research Database (Denmark)

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

    2014-01-01

    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...... and the manganese(III) zero-field-splitting parameters are unambiguously determined by inelastic neutron scattering to yield J = 33.0(2) cm(-1) (Ĥ = JŜ1·Ŝ2 Hamiltonian definition) and single-ion D = -4.0(1) cm(-1). Additionally, high-field, high-frequency electron paramagnetic resonance and magnetic measurements...... 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...

  1. Comparison of thallium deposition with segmental perfusion in pigs with chronic hibernating myocardium.

    Science.gov (United States)

    Baldwa, Sunil; Rana, Muzamil; Canty, John M; Fallavollita, James A

    2008-12-01

    Viable, chronically dysfunctional myocardium with reduced resting flow (or hibernating myocardium) is an important prognostic factor in ischemic heart disease. Although thallium-201 imaging is frequently used to assess myocardial viability in patients with ischemic cardiomyopathy, there are limited data regarding its deposition in hibernating myocardium, and this data suggest that thallium retention may be supernormal compared with control myocardium. Accordingly, pigs (n=7) were chronically instrumented with a 1.5 mm Delrin stenosis on the proximal left anterior descending coronary artery (LAD) to produce hibernating myocardium. Four months later, severe anteroapical hypokinesis was documented with contrast ventriculography (wall motion score, 0.7+/-0.8; normal=3), and microsphere measurements confirmed reduced resting flow (LAD subendocardium, 0.78+/-0.34 vs. 0.96+/-0.24 ml.min(-1).g(-1) in remote; P<0.001). Absolute deposition of thallium-201 and insulin-stimulated [18F]-2 fluoro-2-deoxyglucose (FDG) were assessed over 1 h and compared with resting flow (n=704 samples). Thallium-201 deposition was only weakly correlated with perfusion (r2=0.20; P<0.001) and was more homogeneously distributed (relative dispersion, 0.12+/-0.03 vs. 0.29+/-0.10 for microsphere flow; P<0.01). Thus after 1 h relative thallium-201 (subendocardium LAD/remote, 0.96+/-0.16) overestimated relative perfusion (0.78+/-0.32; P<0.0001) and underestimated the relative reduction in flow. Viability was confirmed by both histology and preserved FDG uptake. We conclude that under resting conditions, thallium-201 redistribution in hibernating myocardium is nearly complete within 1 h, with similar deposition to remote myocardium despite regional differences in flow. These data suggest that in this time frame thallium-201 deposition may not discriminate hibernating myocardium from dysfunction myocardium with normal resting flow. Since hibernating myocardium has been associated with a worse prognosis

  2. 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 ...

  3. Thallium uptake and biological behaviour in childhood brain tumours

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, E.J.; Howman-Giles, R.; Kellie, S.; Uren, R.F. [Royal Alexandra Hospital for Children, Sydney, NSW (Australia)

    1998-03-01

    Full text: The histopathological grade and radiological appearance of the diverse cerebral neoplasms in childhood frequently poorly reflect their biological behaviour. We examined thallium accumulation prior to treatment (and in several cases, at intervals there after) in 13 children to determine its usefulness as a tumour marker. 23 SPECT studies were acquired 20 minutes after the injection of 1-3 mCi of {sup 201}TI. Thallium index (TI), the ratio of counts in tumour/normal brain, was calculated. No uptake was seen in two patients (pts) with a Grade 1 cerebellar astrocytomas (disease free at 4/12 f/u). Three pts with medulloblastomas were studied. One pt showed intense uptake (Tl =12). His tumour (proliferative antigen stain Ki67 = 50%) recurred early after debulking surgery (Tl +ve prior to CT or MRI changes). The second pt was imaged at relapse (Ki67 = 60%) and showed intense uptake, Tl = 17. The third pt showed lower level uptake (Tl = 2), Ki67 = 5%, and is disease-free at 5/12 (as per {sup 201}TI and MRI). One pt with a Grade 1 brainstem glioma showed Tl = 5 and has progressed rapidly despite low grade histology. Four pts with chiasmatic-hypothalamic gliomas have been studied. Although these neoplasms are usually low grade histologically, their growth properties vary greatly. Two pts with Tl<2.5 have been conservatively managed because of slow tumour growth. The other two pts have Tl>3.5 and have required aggressive treatment for rapid disease progression. One pt with a large pilocytic astrocytoma of the optic chiasm showed Tl = 9.5. Active treatment was not undertaken. One pt with a pineal germ cell tumour showed avid {sup 201}TI uptake (Tl not performed) and has had two normal studies, and is clinically well, since BMT. Avid {sup 201}TI uptake also seen in one pt with cerebral neuroblastoma. (Died at 8/12 after Dx.) Thus, {sup 201}TI accumulates in histologically diverse paediatric neoplasms. The Tl appears to reflect biological behaviour in the limited

  4. Salt fluoridation and oral health

    Directory of Open Access Journals (Sweden)

    Thomas M. Marthaler

    2013-11-01

    Full Text Available The aim of this paper is to make known the potential of fluoridated salt in community oral health programs, particularly in South Eastern Europe. Since 1922, the addition of iodine to salt has been successful in Switzerland. Goiter is virtually extinct. By 1945, the cariesprotective effect of fluorides was well established. Based on the success of water fluoridation, a gynecologist started adding of fluoride to salt. The sale of fluoridated salt began in 1956 in the Swiss Canton of Zurich, and several other cantons followed suit. Studies initiated in the early seventies showed that fluoride, when added to salt, inhibits dental caries. The addition of fluoride to salt for human consumption was officially authorized in 1980-82. In Switzerland 85% of domestic salt consumed is fluoridated and 67% in Germany. Salt fluoridation schemes are reaching more than one hundred million in Mexico, Colombia, Peru and Cuba. The cost of salt fluoridation is very low, within 0.02 and 0.05 € per year and capita. Children and adults of the low socio-economic strata tend to have substantially more untreated caries than higher strata. Salt fluoridation is by far the cheapest method for improving oral health. Conclusions. Salt fluoridation has cariostatic potential like water fluoridation (caries reductions up to 50%. In Europe, meaningful percentages of users have been attained only in Germany (67% and Switzerland (85%. In Latin America, there are more than 100 million users, and several countries have arrived at coverage of 90 to 99%. Salt fluoridation is by far the cheapest method of caries prevention, and billions of people throughout the world could benefit from this method.

  5. Evaluation of muscular lesions in connective tissue diseases: thallium 201 muscular scans

    Energy Technology Data Exchange (ETDEWEB)

    Guillet, G.; Guillet, J.; Sanciaume, C.; Maleville, J.; Geniaux, M.; Morin, P.

    1988-04-01

    We performed thallium 201 muscle scans to assess muscular involvement in 40 patients with different connective tissue diseases (7 with dermatomyositis, 7 with systemic lupus erythematosus, 12 with progressive systemic scleroderma, 2 with calcinosis, Raynaud's phenomenon, esophageal involvement, sclerodactyly, and telangiectasia (CREST) syndrome, 3 with monomelic scleroderma, 6 with morphea, and 3 with Raynaud's disease). Only 12 of these patients complained of fatigability and/or myalgia. Electromyography was performed and serum levels of muscle enzymes were measured in all patients. Comparison of thallium 201 exercise recording with the other tests revealed that scan sensitivity is greater than electromyographic and serum muscle enzymes levels. Thallium 201 scans showed abnormal findings in 32 patients and revealed subclinical lesions in 18 patients, while electromyography findings were abnormal in 25 of these 32 patients. Serum enzyme levels were raised in only 8 patients. Thallium 201 scanning proved to be a useful guide for modifying therapy when laboratory data were conflicting. It was useful to evaluate treatment efficacy. Because our data indicate a 100% positive predictive value, we believe that thallium 201 scanning should be advised for severe systemic connective tissue diseases with discordant test results.

  6. Exercise-induced thallium-201 myocardial perfusion defects in angina pectoris without significant coronary artery stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Nakazato, Masayasu; Maruoka, Yuji; Sunagawa, Osahiko; Kinjo, Kunihiko; Tomori, Masayuki; Fukiyama, Koshiro (Ryukyu Univ., Nishihara, Okinawa (Japan). School of Medicine)

    1990-01-01

    We performed exercise thallium-201 myocardial scintigraphy in 32 patients with angina pectoris to study the incidence of perfusion defects, who had no significant organic stenosis on coronary angiography. None of them had myocardial infarction or cardiomyopathy. Thallium-201 myocardial scintigraphy and 12-lead ECG recording were performed during supine bicycle ergometer exercise. Perfusion defects in thallium-201 scintigrams in SPECT images were assessed during visual analysis by two observers. In the coronary angiograms obtained during intravenous infusion of nitroglycerin, the luminal diameter of 75% stenosis or less in the AHA classification was regarded as an insignificant organic stenosis. Myocardial perfusion defects in the thallium-201 scintigrams were detected in eight (25%) of the 32 patients. Six of these eight patients had variant angina documented during spontaneous attacks with ST elevations in standard 12-lead ECGs. Perfusion defects were demonstrated at the inferior or infero-posterior regions in six patients, one of whom had concomitant anteroseptal defect. The defects were not always accompanied by chest pain. All but one patient demonstrating inferior or inferoposterior defects showed ST depression in leads II, III and aV{sub F} on their ECGs, corresponding to inferior wall ischemia. The exception was a case with right bundle branch block. Thus, 25% of the patients with angina pectoris, who had no evidence of significant organic stenosis on their coronary angiograms, exhibited exercise-induced perfusion defects in their thallium-201 scintigrams. Coronary spasms might have caused myocardial ischemia in these patients. (author).

  7. Advanced crystal growth techniques for thallium bromide semiconductor radiation detectors

    Science.gov (United States)

    Datta, Amlan; Becla, Piotr; Guguschev, Christo; Motakef, Shariar

    2018-02-01

    Thallium Bromide (TlBr) is a promising room-temperature radiation detector candidate with excellent charge transport properties. Currently, Travelling Molten Zone (TMZ) technique is widely used for growth of semiconductor-grade TlBr crystals. However, there are several challenges associated with this type of crystal growth process including lower yield, high thermal stress, and low crystal uniformity. To overcome these shortcomings of the current technique, several different crystal growth techniques have been implemented in this study. These include: Vertical Bridgman (VB), Physical Vapor Transport (PVT), Edge-defined Film-fed Growth (EFG), and Czochralski Growth (Cz). Techniques based on melt pulling (EFG and Cz) were demonstrated for the first time for semiconductor grade TlBr material. The viability of each process along with the associated challenges for TlBr growth has been discussed. The purity of the TlBr crystals along with its crystalline and electronic properties were analyzed and correlated with the growth techniques. Uncorrected 662 keV energy resolutions around 2% were obtained from 5 mm x 5 mm x 10 mm TlBr devices with virtual Frisch-grid configuration.

  8. Thallium distribution in sediments from the Pearl river basin, China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Juan [Guangzhou University, Key Laboratory of Waters Safety and Protection in the Pearl River Delta, Ministry of Education, Guangzhou (China); Forschungszentrum Dresden-Rossendorf (FZD), Institute of Radiochemistry, Research Site Leipzig, Leipzig (Germany); Wang, Jin; Chen, Yongheng [Guangzhou University, Key Laboratory of Waters Safety and Protection in the Pearl River Delta, Ministry of Education, Guangzhou (China); Qi, Jianying [Department of Environmental Science and Engineering, Guangzhou University, Guangzhou (China); Lippold, Holger [Forschungszentrum Dresden-Rossendorf (FZD), Institute of Radiochemistry, Research Site Leipzig, Leipzig (Germany); Wang, Chunlin [Guangdong Provincial Academy of Environmental Science, Guangzhou (China)

    2010-10-15

    Thallium (Tl) is a rare element of high toxicity. Sediments sampled in three representative locations near industries utilizing Tl-containing raw materials from the Pearl River Basin, China were analyzed for their total Tl contents and the Tl contents in four sequentially extracted fractions (i.e., weak acid exchangeable, reducible, oxidizable, and residual fraction). The results reveal that the total Tl contents (1.25-19.1 {mu}g/g) in the studied sediments were slightly high to quite high compared with those in the Chinese background sediments. This indicates the apparent Tl contamination of the investigated sediments. However, with respect to the chemical fractions, Tl is mainly associated with the residual fraction (>60%) of the sediments, especially of those from the mining area of Tl-bearing pyrite minerals, indicating the relatively low mobility, and low bioavailability of Tl in these sediments. This obviously contrasts with the previous findings that Tl is mainly entrapped in the first three labile fractions of the contaminated samples. Possible reasons were given for the dominating association of Tl with the residual fraction (>95%) of the mining area sediments. The significant role of certain K-containing silicates or minerals of these sediments on retaining Tl in the residual fraction, discovered by this study, provides a special field of research opportunity for the Tl-containing wastewater treatment. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Health Effects Associated with Water Fluoridation.

    Science.gov (United States)

    Richmond, Virginia L.

    1979-01-01

    Discussion is presented concerning fluoridation of water supplies. Correlation between fluoride in drinking water and improved dental health is reviewed. Relationship is expressed between fluoridation and reduced tooth decay. Use of fluoride in treating skeletal disorders is discussed. Author advocates fluoridating water supplies. (SA)

  10. Use of fluorides in dental caries management.

    Science.gov (United States)

    Chu, C H; Mei, May L; Lo, Edward C M

    2010-01-01

    Fluoride is commonly and widely used to prevent and even arrest caries. The clinical effects of fluorides depend on the chemical compounds utilized and the methods used to apply the fluoride ion to the surface of the tooth. Fluorosis has been reported in conjunction with increased doses of fluoride. A coordinated approach to fluoride delivery is essential to avoid the risk of fluorosis.

  11. [Graphite furnace atomic absorption spectrometry for determination of thallium in blood].

    Science.gov (United States)

    Zhang, Q L; Gao, G

    2016-04-20

    Colloidal palladium was used as chemical modifier in the determination of blood thallium by graphite furnace atomic absorption spectrometry. Blood samples were precipitated with 5% (V/V)nitric acid, and then determined by GFAAS with colloidal palladium used as a chemical modifier. 0.2% (W/V)sodium chloride was added in the standard series to improve the matrix matching between standard solution and sample. The detection limit was 0.2 μg/L. The correlation coefficient was 0.9991. The recoveries were between 93.9% to 101.5%.The relative standard deviations were between 1.8% to 2.7%.The certified reference material of whole blood thallium was determined and the result was within the reference range Conclusion: The method is accurate, simple and sensitive, and it can meet the needs of detection thallium in blood entirely.

  12. Myocardial perfusion defect on thallium-201 imaging in patients with chronic obstructive pulmonary disease

    Energy Technology Data Exchange (ETDEWEB)

    Mehrotra, P.P.; Weaver, Y.J.; Higginbotham, E.A.

    1983-08-01

    Six patients with angina pectoris had reversible perfusion defects on stress and redistribution thallium imaging. Three patients had a positive electrocardiographic response to exercise. No significant coronary artery lesions were seen on coronary arteriography in any of the six patients. All had mild to moderate hypoxemia at rest and physiologic evidence of chronic obstructive pulmonary disease as defined by the decrease in the ratio of forced expiratory volume at 1 second to forced vital capacity (FEV1/FVC X 100) or decrease in the forced midexpiratory flow rate (FEF25-75), or both. None had clinical findings suggestive of any of the reported causes of positive thallium scans in patients with normal coronary arteriograms. Cellular dysfunction produced by hypoxemia affecting the uptake of thallium seems to be the most likely mechanism of this abnormality.

  13. Early and delayed thallium-201 scintigraphy in thyroid nodules: the relationship between early thallium-201 uptake and perfusion

    Energy Technology Data Exchange (ETDEWEB)

    Derebek, E. [Dept. of Nuclear Medicine, Dokuz Eylul Univ., School of Medicine, Izmir (Turkey); Biberoglu, S. [Dept. of Internal Medicine, Div. of Endocrinology, Dokuz Eylul Univ., School of Medicine, Izmir (Turkey); Kut, O. [Dept. of Nuclear Medicine, Dokuz Eylul Univ., School of Medicine, Izmir (Turkey); Yesil, S. [Dept. of Internal Medicine, Div. of Endocrinology, Dokuz Eylul Univ., School of Medicine, Izmir (Turkey); Saydam, S. [Dept. of Surgery, Dokuz Eylul Univ., School of Medicine, Izmir (Turkey); Yilmaz, M. [Dept. of Nuclear Medicine, Dokuz Eylul Univ., School of Medicine, Izmir (Turkey); Yenici, O. [Dept. of Nuclear Medicine, Dokuz Eylul Univ., School of Medicine, Izmir (Turkey); Igci, E. [Dept. of Radiology, Dokuz Eylul Univ., School of Medicine, Izmir (Turkey); Gokce, O. [Dept. of Surgery, Dokuz Eylul Univ., School of Medicine, Izmir (Turkey); Canda, S. [Dept. of Pathology, Dokuz Eylul Univ., School of Medicine, Izmir (Turkey); Bueyuekgebiz, A. [Dept. of Pediatrics, Dokuz Eylul Univ., School of Medicine, Izmir (Turkey); Dogan, A.S. [Dept. of Nuclear Medicine, Dokuz Eylul Univ., School of Medicine, Izmir (Turkey); Durak, H. [Dept. of Nuclear Medicine, Dokuz Eylul Univ., School of Medicine, Izmir (Turkey)

    1996-05-01

    Seventy-six patients with tyroid nodules were studied. Initially, 75 MBq of thallium-201 was injected. The thyroid gland was imaged 15 min (early) and 3 h (delayed) after the injection. Thereafter, 185 MBq technetium-99m pertechnetate was injected. Immediately after the injection, a 1-min perfusion image was acquired, followed by an image at 20 min. Increased early and delayed {sup 201}Tl uptake compared with the contralateral thyroid tissue was adopted as the criterion for malignancy. Sensitivity, specificity and negative predictive values were found to be 85%, 64% and 78%, respectively, in operated patients, but these values were 86%, 87% and 95%, respectively, in the whole group, including patients followed with fine-needle aspiration biopsy. With the purpose of investigating the relationship between perfusion and early {sup 201}Tl uptake, bot perfusion and early images were graded comparing nodular activity with contralateral thyroid activity. There was a poor correlation between perfusion and {sup 201}Tl uptake. The correlation was even worse in hyperactive nodules. It is concluded that early and delayed {sup 201}Tl imaging should not be used in the differential diagnosis of cold nodules and that early {sup 201}Tl uptake seems to be more closely related to factors other than perfusion. (orig.)

  14. Comparison of Fluoridated Miswak and Toothbrushing with Fluoridated Toothpaste on Plaque Removal and Fluoride Release.

    Science.gov (United States)

    Baeshen, Hosam; Salahuddin, Sabin; Dam, Robel; Zawawi, Khalid H; Birkhed, Dowen

    2017-04-01

    Dental caries and periodontal diseases are all induced by oral biofilm (dental plaque). This study was conducted to evaluate if fluoride-impregnated miswak is as effective in plaque removal and fluoride release as toothbrushing with fluoride toothpaste. This single-blind, randomized, crossover study was conducted at the Department of Cariology, University of Gothenburg, Gothenburg, Sweden, from February 2010 to January 2011. Fifteen healthy subjects participated in this study. The participants were instructed to use the following: (1) 0.5% NaF-impregnated miswak, (2) nonfluoridated miswak, (3) toothbrush with nonfluoride toothpaste, and (4) toothbrush with 1450 ppm fluoride toothpaste. Each method was used twice a day for 1 week after which plaque amount and fluoride concentration in resting saliva were measured. There was a 1-week washout period between each method. No significant difference between miswak and tooth-brushing was found regarding plaque removal on buccal and lingual surfaces. A somewhat higher fluoride concentration in resting saliva was found after using impregnated miswak when compared with toothbrushing with fluoride toothpaste (p toothbrushing showed the same plaque removing effect on buccal and lingual surfaces. Miswak impregnated with 0.5% NaF resulted in a higher concentration of fluoride in saliva than brushing with 1450 ppm fluoride toothpaste. Miswak impregnated with 0.5% NaF and toothbrushing results in comparable plaque removal and about the same fluoride concentration in saliva even it was somewhat higher for impregnated miswak.

  15. Overlapping toxic effect of long term thallium exposure on white mustard (Sinapis alba L.) photosynthetic activity.

    Science.gov (United States)

    Mazur, Radosław; Sadowska, Monika; Kowalewska, Łucja; Abratowska, Agnieszka; Kalaji, Hazem M; Mostowska, Agnieszka; Garstka, Maciej; Krasnodębska-Ostręga, Beata

    2016-09-02

    Heavy metal exposure affect plant productivity by interfering, directly and indirectly, with photosynthetic reactions. The toxic effect of heavy metals on photosynthetic reactions has been reported in wide-ranging studies, however there is paucity of data in the literature concerning thallium (Tl) toxicity. Thallium is ubiquitous natural trace element and is considered the most toxic of heavy metals; however, some plant species, such as white mustard (Sinapis alba L.) are able to accumulate thallium at very high concentrations. In this study we identified the main sites of the photosynthetic process inhibited either directly or indirectly by thallium, and elucidated possible detoxification mechanisms in S. alba. We studied the toxicity of thallium in white mustard (S. alba) growing plants and demonstrated that tolerance of plants to thallium (the root test) decreased with the increasing Tl(I) ions concentration in culture media. The root growth of plants exposed to Tl at 100 μg L(-1) for 4 weeks was similar to that in control plants, while in plants grown with Tl at 1,000 μg L(-1) root growth was strongly inhibited. In leaves, toxic effect became gradually visible in response to increasing concentration of Tl (100 - 1,000 μg L(-1)) with discoloration spreading around main vascular bundles of the leaf blade; whereas leaf margins remained green. Subsequent structural analyses using chlorophyll fluorescence, microscopy, and pigment and protein analysis have revealed different effects of varying Tl concentrations on leaf tissue. At lower concentration partial rearrangement of the photosynthetic complexes was observed without significant changes in the chloroplast structure and the pigment and protein levels. At higher concentrations, the decrease of PSI and PSII quantum yields and massive oxidation of pigments was observed in discolored leaf areas, which contained high amount of Tl. Substantial decline of the photosystem core proteins and disorder of the

  16. [Water fluoridation and public health].

    Science.gov (United States)

    Barak, Shlomo

    2003-11-01

    Fluoridation in Israel was first mooted in 1973 and finally incorporated into law in November 2002 obligating the Ministry of Health to add fluoride to the nation's water supply. Epidemiology studies in the USA have shown that the addition of one part per million of fluoride to the drinking water reduced the caries rate of children's teeth by 50% to 60% with no side effects. Both the WHO in 1994 and the American Surgeon General's report of 2000 declared that fluoridation of drinking water was the safest and most efficient way of preventing dental caries in all age groups and populations. Opposition to fluoridation has arisen from "antifluoridation" groups who object to the "pollution" of drinking water by the addition of chemicals and mass medication in violation of the "Patient's Rights" law and the Basic Law of Human Dignity and Liberty. A higher prevalence of hip fractures in elderly osteoporotic women and osteosarcoma in teenagers has been reported in areas where excess fluoride exists in the drinking water. However, none of the many independent professional committees reviewing the negative aspects of fluoridation have found any scientific evidence associating fluoridation with any ill-effects or health problems. In Israel, where dental treatment is not included in the basket of Health Services, fluoridation is the most efficient and cheapest way of reducing dental disease, especially for the poorer members of the population.

  17. Stable room-temperature thallium bromide semiconductor radiation detectors

    Science.gov (United States)

    Datta, A.; Fiala, J.; Becla, P.; Motakef, Shariar

    2017-10-01

    Thallium bromide (TlBr) is a highly efficient ionic semiconductor with excellent radiation detection properties. However, at room temperature, TlBr devices polarize under an applied electric field. This phenomenon not only degrades the charge collection efficiency of the detectors but also promotes chemical reaction of the metal electrodes with bromine, resulting in an unstable electric field and premature failure of the device. This drawback has been crippling the TlBr semiconductor radiation detector technology over the past few decades. In this exhaustive study, this polarization phenomenon has been counteracted using innovative bias polarity switching schemes. Here the highly mobile Br- species, with an estimated electro-diffusion velocity of 10-8 cm/s, face opposing electro-migration forces during every polarity switch. This minimizes the device polarization and availability of Br- ions near the metal electrode. Our results indicate that it is possible to achieve longer device lifetimes spanning more than 17 000 h (five years of 8 × 7 operation) for planar and pixelated radiation detectors using this technique. On the other hand, at constant bias, 2500 h is the longest reported lifetime with most devices less than 1000 h. After testing several biasing switching schemes, it is concluded that the critical bias switching frequency at an applied bias of 1000 V/cm is about 17 μHz. Using this groundbreaking result, it will now be possible to deploy this highly efficient room temperature semiconductor material for field applications in homeland security, medical imaging, and physics research.

  18. Thallium pollution in China: A geo-environmental perspective.

    Science.gov (United States)

    Xiao, Tangfu; Yang, Fei; Li, Shehong; Zheng, Baoshan; Ning, Zengping

    2012-04-01

    It is well known that thallium (Tl) is a non-essential and toxic metal to human health, but less is known about the geo-environmentally-induced Tl pollution and its associated health impacts. High concentrations of Tl that are primarily associated with the epithermal metallogenesis of sulfide minerals have the potential of producing Tl pollution in the environment, which has been recognized as an emerging pollutant in China. This paper aims to review the research progress in China on Tl pollution in terms of the source, mobility, transportation pathway, and health exposure of Tl and to address the environmental concerns on Tl pollution in a geo-environmental perspective. Tl associated with the epithermal metallogenesis of sulfide minerals has been documented to disperse readily and accumulate through the geo-environmental processes of soil enrichment, water transportation and food crop growth beyond a mineralized zone. The enrichments of Tl in local soil, water, and crops may result in Tl pollution and consequent adverse health effects, e.g. chronic Tl poisoning. Investigation of the baseline Tl in the geo-environment, proper land use and health-related environmental planning and regulation are critical to prevent the Tl pollution. Examination of the human urinary Tl concentration is a quick approach to identify exposure of Tl pollution to humans. The experiences of Tl pollution in China can provide important lessons for many other regions in the world with similar geo-environmental contexts because of the high mobility and toxicity of Tl. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Stable room-temperature thallium bromide semiconductor radiation detectors

    Directory of Open Access Journals (Sweden)

    A. Datta

    2017-10-01

    Full Text Available Thallium bromide (TlBr is a highly efficient ionic semiconductor with excellent radiation detection properties. However, at room temperature, TlBr devices polarize under an applied electric field. This phenomenon not only degrades the charge collection efficiency of the detectors but also promotes chemical reaction of the metal electrodes with bromine, resulting in an unstable electric field and premature failure of the device. This drawback has been crippling the TlBr semiconductor radiation detector technology over the past few decades. In this exhaustive study, this polarization phenomenon has been counteracted using innovative bias polarity switching schemes. Here the highly mobile Br− species, with an estimated electro-diffusion velocity of 10−8 cm/s, face opposing electro-migration forces during every polarity switch. This minimizes the device polarization and availability of Br− ions near the metal electrode. Our results indicate that it is possible to achieve longer device lifetimes spanning more than 17 000 h (five years of 8 × 7 operation for planar and pixelated radiation detectors using this technique. On the other hand, at constant bias, 2500 h is the longest reported lifetime with most devices less than 1000 h. After testing several biasing switching schemes, it is concluded that the critical bias switching frequency at an applied bias of 1000 V/cm is about 17 μHz. Using this groundbreaking result, it will now be possible to deploy this highly efficient room temperature semiconductor material for field applications in homeland security, medical imaging, and physics research.

  20. Medical geology of arsenic, selenium and thallium in China.

    Science.gov (United States)

    Li, Shehong; Xiao, Tangfu; Zheng, Baoshan

    2012-04-01

    Arsenic (As), selenium (Se) and thallium (Tl) are three trace metals (metalloids) of high concern in China because deficiency or excess expose can cause a range of endemic diseases, such as endemic arsenism, selenosis, Keshan disease (KD), Kashin-Beck disease (KBD) and thallotoxicosis. These specific endemic diseases were attributable for overabundance or deficiency (mainly referring to selenium) of these three elements in the local environment as a result of natural geochemical processes and/or anthropologic activities. The geochemistry and human health impacts of these three trace elements have been intensively studied since the 1970s in China, in terms of geochemical sources, distribution, transportation, health impact pathways, and prevention/remediation measures. Endemic arsenism in China are induced from the exposures of high As in either drinking water or domestic combustion of As-rich coals. Both endemic selenium deficiency and selenosis occurred in China. The KD and KBD were related to the deficiency of Se in the low-Se geological belt with Se contents in soil less than 0.125mg/kg stretching from northeast to southwest of China. Endemic selenosis occurred in areas with high Se concentrations in soils derived from the Se-enriched black carbonaceous siliceous rocks, carbonaceous shale and slate. Endemic Tl poisoning occurred in southwestern China due to Tl contamination in local drinking water and vegetables surrounding the Tl-rich sulfide mineralized areas. Some measures have been taken to control and remedy the endemic diseases with significant effects in reducing health risk and damage of As, Se and Tl. However, the states of the endemic diseases of As, Se and Tl in China are still serious in some areas, and substantial research efforts regarding the health impacts of these elements are further required. This paper reviews the progress of medical geology of As, Se and Tl in China, and provides with some outlooks for future research directions. Copyright

  1. Drinking water fluoridation and bone.

    Science.gov (United States)

    Allolio, B; Lehmann, R

    1999-01-01

    Drinking water fluoridation has an established role in the prevention of dental caries, but may also positively or negatively affect bone. In bone fluoride is incorporated into hydroxylapatite to form the less soluble fluoroapatite. In higher concentrations fluoride stimulates osteoblast activity leading to an increase in cancellous bone mass. As optimal drinking water fluoridation (1 mg/l) is widely used, it is of great interest, whether long-term exposition to artificial water fluoridation has any impact on bone strength, bone mass, and -- most importantly -- fracture rate. Animal studies suggest a biphasic pattern of the effect of drinking water fluoridation on bone strength with a peak strength at a bone fluoride content of 1200 ppm followed by a decline at higher concentrations eventually leading to impaired bone quality. These changes are not paralleled by changes in bone mass suggesting that fluoride concentrations remain below the threshold level required for activation of osteoblast activity. Accordingly, in most epidemiological studies in humans bone mass was not altered by optimal drinking water fluoridation. In contrast, studies on the effect on hip fracture rate gave conflicting results ranging from an increased fracture incidence to no effect, and to a decreased fracture rate. As only ecological studies have been performed, they may be biased by unknown confounding factors -- the so-called ecological fallacy. However, the combined results of these studies indicate that any increase or decrease in fracture rate is likely to be small. It has been calculated that appropriately designed cohort studies to solve the problem require a sample size of >400,000 subjects. Such studies will not be performed in the foreseeable future. Future investigations in humans should, therefore, concentrate on the effect of long-term drinking water fluoridation on bone fluoride content and bone strength.

  2. New CZT cardiac cameras and myocardial perfusion imaging with thallium 201; Nouvelles cameras cardiaques a semi-conducteur cadmium -zinc- telluride (CZT) et scintigraphies myocardiques au thallium 201

    Energy Technology Data Exchange (ETDEWEB)

    Songy, B. [Service de medecine et imagerie nucleaire, centre cardiologique du Nord (CCN), 93 - Saint-Denis (France)

    2010-08-15

    Myocardial perfusion imaging is widely used for management of coronary artery disease. However, it suffers from technical limitations. New cardiac cameras using CZT detectors are now available and increase spatial (x2) and energy (x2) resolutions and photons sensitivity (x5). We describe here the General Electric Discovery NM 530c new camera and summarize the validation studies with technetium agents and with thallium 201, protocols to reduce doses, ultrafast protocols and perspectives offered with this new technology. (author)

  3. Treating hypersensitivity with fluoride varnish.

    Science.gov (United States)

    Gaffar, A

    1999-01-01

    Dentinal hypersensitivity results when stimulation causes the fluid in open dentinal tubules to undergo pressure changes, which activates mechanoreceptor nerves and results in pain. Treatment with fluoride varnish forms a protective layer of calcium fluoride that prevents this fluid flow, thereby reducing dentinal sensitivity.

  4. Treating hypersensitivity with fluoride varnishes.

    Science.gov (United States)

    Gaffar, A

    1998-11-01

    Dentinal hypersensitivity results when stimulation causes the fluid in open dentinal tubules to undergo pressure changes, which activates mechanoreceptor nerves and results in pain. Treatment with fluoride varnish forms a protective layer of calcium fluoride that prevents this fluid flow, thereby reducing dentinal sensitivity.

  5. Prediction for new magnetoelectric fluorides

    OpenAIRE

    Nenert, G.; Palstra, T. T. M.

    2007-01-01

    We use symmetry considerations in order to predict new magnetoelectric fluorides. In addition to these magnetoelectric properties, we discuss which among these fluorides are the ones susceptible to present multiferroic properties. We emphasize that several materials exhibit ferromagnetic properties. This ferromagnetism should enhance the interplay between the magnetic and dielectric properties in these materials.

  6. Genotoxic and mutagenic effects of the diagnostic use of thallium-201 in nuclear medicine

    Energy Technology Data Exchange (ETDEWEB)

    Kelsey, K.T. (Harvard School of Public Health, Boston, MA (United States)); Donohoe, K.J. (Beth Israel Hospital, Boston, MA (United States). Div. of Nuclear Medicine); Baxter, Barbara; Memisoglu, Asli; Little, J.B.; Caggana, Michele; Liber, H.L. (Harvard School of Public Health, Boston, MA (United States))

    1991-07-01

    In order to investigate possible mutagenetic effects of in vivo exposure to low levels of ionizing radiation used in nuclear medicine, the authors examined hypoxanthine guanine phosphoribosyl transferase (hprt) mutant fraction (MF) and chromosome aberration (CA) frequency in 24 nuclear medicine patients before and after injection of thallium-201. The mean MF of the thallium-201-exposed cohort was 5.2{+-}4.4 x 10{sup -6} before injection exposure. No significant difference in MF was observed 24 h later. In 11 patients who were studied on a 3rd occasion, 30 days after thallium-201 exposure, there was again no significant difference in post-exposure as compared with the pre-exposure MF. The frequency of CA in peripheral blood lymphocytes was not significantly different, comparing pre- and 24h to 1 month post-radionuclide exposure . Thus, thallium-201 exposure was not associated with significant elevations in MF or CA frequency in lymphocytes of exposed individuals. (author). 40 refs.; 3 tabs.

  7. Systematics of c-axis Phonons in the Thallium- and Bismuth-Based Cuprate Superconductors

    NARCIS (Netherlands)

    Tsvetkov, A. A; Dulic, D.; Marel, D. van der; Damascelli, A.; Kaljushnaia, G. A.; Gorina, J. I.; Senturina, N. N.; Kolesnikov, N. N.; Ren, Z. F.; Wang, J. H.; Menovsky, A. A.; Palstra, T. T. M.

    2006-01-01

    Published in: Phys. Rev. B 60 (1999) 13196 Citing articles (CrossRef) citations recorded in [Science Citation Index] Abstract: We present grazing incidence reflectivity measurements in the far infrared region at temperatures above and below Tc for a series of thallium (Tl2Ba2CuO6, Tl2Ba2CaCu2O8) and

  8. Dipyridamole-thallium-201 tomography documenting improved myocardial perfusion with therapy in Kawasaki disease

    Energy Technology Data Exchange (ETDEWEB)

    Nienaber, C.A.; Spielmann, R.P.; Hausdorf, G.

    1988-12-01

    Thallium-201 tomographic perfusion studies after pharmacologic vasodilation were performed in seven children (aged 2 years 8 months to 8 years 7 months), 3 to 20 months after the acute stage of the disease. In all patients coronary aneurysms were seen on cross-sectional echocardiograms. The scintigrams of six children showed no significant regional reduction of myocardial thallium-201 uptake. These children had remained asymptomatic in the follow-up period after the acute inflammatory stage of Kawasaki disease. Persistent and transient thallium defects were present in one child with acute posterolateral myocardial infarction; obstruction of two coronary vessels supplying the defect zones was confirmed by contrast angiography. After 8 months of treatment a follow-up nuclear scan showed marked reduction in the size of the defect and almost complete abolishment of the ischemic reaction. Thus tomographic thallium-201 perfusion scintigraphy in conjunction with vasodilation stress is useful to assess myocardial perfusion in children with Kawasaki disease and demonstrates marked improvement in regional perfusion after adequate medical therapy.

  9. Complexometric determination of thallium(III using ethanethiol as a selective masking agent

    Directory of Open Access Journals (Sweden)

    Karthikeyan J.

    2006-01-01

    Full Text Available A simple and selective complexometric method for the determination of thallium in presence of other metal ions is proposed based on the selective masking ability of ethanethiol towards thallium(III. Thallium present in a given sample solution is first complexed with a known excess of EDTA and the surplus EDTA is titrated with standard zinc sulphate solution at pH 5-6(hexamine using xylenol orange as the indicator. A 0.3% aqueous solution of ethanethiol is then added to displace EDTA from the Tl(III-EDTA complex. The released EDTA is titrated with standard zinc sulphate solution as before. Reproducible and accurate results are obtained for 3.70 mg to 74.07 mg of Tl (III with relative error less than ? 0.44% and coefficient of variation not more than 0.27%. The interference of various ions was studied and the method was used for the analysis of thallium in its synthetic alloy mixtures and also in complexes.

  10. Thallium-201: Autoradiography in pigmented mice and melanin-binding in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Tjaelve, H.; Nilsson, M.; Larsson, B. (Uppsala Univ. (Sweden))

    1982-01-01

    Autoradiography with /sup 201/Tl/sup +/ in C57Bl mice showed a strong labelling of the eye melanin and of pigmented hair follicles. An analysis of the affinity of thallium for pigment from cow eyes indicated a binding to three groups of sites and showed a marked sensitivity to the addition of H/sup +/-ions. The results are consistent with the conception that a binding of thallium occurs to the free carboxyl groups of the melanin and that the structure of the polymer has a marked influence on the affinity. Similar results have previously been obtained with other cations. There was no indication that the strong in vivo affinity of thallium to melanin is due to a more firm binding than for other cations which do not localize on melanin in vivo. Instead, the ability of cations to pass the melanocyte membranes and reach the melanin granules is probably decisive for whether a melanin-binding will take place in vivo. Toxic effects on the eye and epilation are symptoms of thallium intoxication which may be related to its melanin-binding. The fate of /sup 201/Tl/sup +/ in some other tissues is also described and discussed.

  11. Laser-assisted decay and optical spectroscopy studies of neutron-deficient thallium isotopes

    CERN Document Server

    Van Beveren, Céline; Huyse, Mark

    The neutron-deficient thallium isotopes with one proton less than the Z = 82 shell closure, are situated in an interesting region of the nuclear chart, notorious for intruder states and shape coexistence. Shape coexistence is the remarkable phenomenon in which two or more distinct types of deformation occur at low energy in the same atomic nucleus. Shape coexistence has been studied intensively, experimentally as well as theoretically in different nuclei in the light-lead region and the isomerism in the thallium isotopes was among the first indications of this phenomenon. Different shapes, whose structure has been linked to specific proton orbitals above and below the Z = 82 shell closure, are present at low energy in the neutron-deficient odd-mass thallium nuclei. In the odd-odd nuclei, the coupling of an unpaired proton and unpaired neutron gives rise to multiplets of low-lying states from which some can be isomeric. Since thallium has one proton missing in the major proton shell, and when approaching neutr...

  12. Clinical features and applications of thallium-201. With reference to scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Tadashige

    1988-12-01

    Thallium-201 is not only used widely in myocardial imaging but also has a great potential in other various nuclear medicine imaging studies. This paper presents clinical features and applications of thallium-201, focusing on clinical trials with thallium-201 at the Shinshu University School of Medicine. Thallium-201 myocardial scintigraphy offers information on (1) ventricular position and morphology, (2) hypertrophy or dilatation of the left ventricle, (3) hypertrophy or dilatation of the right ventricle, (4) site and extent of myocardial ischemia and infarct, (5) myocardial blood flow, (6) pulmonary congestion or interstitial pulmonary edema, and (7) pericardial effusion. It can be used in the following evaluation or diagnosis: (1) acute or old myocardial infarction, (2) angina pectoris, (3) treatment strategy or prognosis of ischemic heart disease, (4) treatment strategy or observation of bypass graft or drug therapy, (5) hypertrophic or dilated idiopathic cardiomyopathy, (6) myocardial lesions induced by sarcoidosis, collagen disease, and neuro-muscular disease, (7) ventricular hypertrophy and pulmonary edema, and (9) pericarditis, pericardial effusion, and systolic pericarditis associated with underlying disease. The significance of tumor, liver, bone marrow scintigraphies is also referred to. (Namekawa, K) 69 refs.

  13. Optimised thallium precipitation in a waste water treatment system of the flue gas desulphurisation; Optimierte Thalliumabscheidung einer RAA

    Energy Technology Data Exchange (ETDEWEB)

    Ritzerfeld, Guenter [RWE Power AG, Bergheim (Germany); Birngruber, Ingolf [RWE Power AG, Hamm (Germany); Muelder, Thomas [RWE Power AG, Ibbenbueren (Germany)

    2011-07-01

    When co-combusting substitute fuels in power plants, the element Thallium should be checked in the drain of the waste water treatment system of flue gas desulphurisation. In 2005 Thallium-concentrations exceeding the limit value were determined for the first time as a consequence of the modified analysis of the supervisory authority. The previous lower Thallium concentrations with graphite tube-atomic absorption spectrometry were caused by the high chloride concentration in RAA waste water. The RAA operating mode was checked and changed. Equipment-related weak spots were detected and corrected. (orig.)

  14. Comparison of Polythionates as Precursors for the Formation of Thallium Sulfide Layers

    Directory of Open Access Journals (Sweden)

    Vitalijus JANICKIS

    2011-11-01

    Full Text Available The processes of obtaining layers of thallium, sulfides, TlxSy, by the sorption-diffusion method on polyamide 6 using solutions of lower polythionates - sodium trithionate and tetrathionate, Na2S3O6, Na2S4O6, potassium pentathionate, K2S5O6, and of dodecathionic acid, H2S12O6, as precursors of sulfur are compared. The concentration of sorbed sulfur increases with increasing the duration of treatment, the concentration and temperature of precursor solution. It rather significantly also depends on the nature - sulfurity of polythionate, i. e. on the number of sulfur atoms in the polythionate anion: effectiveness of sulfurization using solutions of dodecathionic acid is significantly higher than that of lower polythionates. Thallium sulfide layers are formed on the surface of polyamide after the treatment of sulfurized polymer with Tl(I salt solution. The concentration of thallium in the layer increases with the increase of initial sulfurization duration and in case of H2S12O6 solution used - on the temperature of this process. The results of X-ray diffraction analysis confirmed the formation of thallium sulfide layers in the surface of polyamide 6. The phase composition of layer changes depending on the conditions of initial treatment in a H2S12O6 solution. Five thallium sulfide phases, two forms of TlS, Tl2S2, Tl4S3 and Tl2S5 were identified in the composition of the layers treated for different time with a solution of dodecathionic acid at the temperature of 20 °C and 30 °C and then with Tl(I salt solution by X-ray diffraction but the maxima of TlS and Tl2S5 phases predominate in the diffractograms.http://dx.doi.org/10.5755/j01.ms.17.4.774

  15. Urinary Fluoride Concentration in Children with Disabilities Following Long-Term Fluoride Tablet Ingestion

    Science.gov (United States)

    Liu, Hsiu-Yueh; Chen, Jung-Ren; Hung, Hsin-Chia; Hsiao, Szu-Yu; Huang, Shun-Te; Chen, Hong-Sen

    2011-01-01

    Urine is the most commonly utilized biomarker for fluoride excretion in public health and epidemiological studies. Approximately 30-50% of fluoride is excreted from urine in children. Urinary fluoride excretion reflects the total fluoride intake from multiple sources. After administering fluoride tablets to children with disabilities, urinary…

  16. Bioactivity and fluoride release of strontium and fluoride modified Biodentine.

    Science.gov (United States)

    Simila, Hazel O; Karpukhina, Natalia; Hill, Robert G

    2018-01-01

    Biodentine™ is a novel tricalcium silicate based material used both as a coronal dentine replacement and in pulp therapy. Its multiple use in sealing perforations, pulp capping and as a temporary restoration arises from its ability to promote dentine formation and to confer an excellent marginal seal. However, there is still room for improvement of this cement as it lacks the anticariogenic effect typically conferred by fluoride ion release as seen in glass ionomer cement based dental materials. Therefore, this study was conducted to investigate the impact of bioactive glass addition to Biodentine™. was to compare the apatite formation capacity, specificity of the apatite type formed and fluoride ion release by Biodentine™ cements that have been modified by three different compositions of bioactive glasses. High fluoride, high strontium and high fluoride plus strontium containing bioactive glasses were synthesized, incorporated into Biodentine™ powder and four types of cements prepared. These cements were immersed in phosphate buffered saline solution and incubated for a period of 3 and 24h, 3, 7 and 14 days. Fourier transform infra-red spectroscopy, X-ray diffraction, magic angle spinning nuclear magnetic resonance and fluoride ion release studies were performed. Bioactive glass addition to Biodentine™ led to pronounced formation of apatite. Where the bioactive glass contained fluoride, fluorapatite and fluoride ion release were demonstrated. Eliciting fluorapatite formation and fluoride ion release from Biodentine™ is an important development as fluoride is known to have antibacterial and anticariogenic effects. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  17. Fluorides in dental public health programs.

    Science.gov (United States)

    Kumar, Jayanth V; Moss, Mark E

    2008-04-01

    The use of fluorides in dental public health programs has a long history. With the availability of fluoridation and other forms of fluorides, dental caries have declined dramatically in the United States. This article reviews some of the ways fluorides are used in public health programs and discusses issues related to their effectiveness, cost, and policy.

  18. 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...

  19. Thermodynamic Study of Tl6SBr4 Compound and Some Regularities in Thermodynamic Properties of Thallium Chalcohalides

    Directory of Open Access Journals (Sweden)

    Dunya Mahammad Babanly

    2017-01-01

    Full Text Available The solid-phase diagram of the Tl-TlBr-S system was clarified and the fundamental thermodynamic properties of Tl6SBr4 compound were studied on the basis of electromotive force (EMF measurements of concentration cells relative to a thallium electrode. The EMF results were used to calculate the relative partial thermodynamic functions of thallium in alloys and the standard integral thermodynamic functions (-ΔfG0, -ΔfH0, and S0298 of Tl6SBr4 compound. All data regarding thermodynamic properties of thallium chalcogen-halides are generalized and comparatively analyzed. Consequently, certain regularities between thermodynamic functions of thallium chalcogen-halides and their binary constituents as well as degree of ionization (DI of chemical bonding were revealed.

  20. Portland Water Fluoridation: A Newspaper Analysis.

    Science.gov (United States)

    Bianchi, Allison; Bergren, Martha Dewey; Lewis, Patricia Ryan

    2017-03-01

    Portland, Oregon is the largest city in the United States without community water fluoridation (CWF). A newspaper analysis was conducted of the failed 2013 CWF campaign to evaluate anti-fluoridation and pro-fluoridation messaging provided by newspapers during the campaign. News content was categorized by type and slant (pro-fluoridation, anti-fluoridation, or neutral) and 34 variables were tabulated (23 anti-fluoridation, 11 pro-fluoridation). Results showed overall messaging was slightly pro-fluoridation, as compared to anti-fluoridation or neutral content (35%, 32%, and 33% respectively). Editorial content was 85% pro-fluoridation and 15% anti-fluoridation. The most frequent anti-fluoridation variables were alternatives to water fluoridation, mass/forced medication and concerns about the political process. Conversely, tooth decay and social justice were the most commonly cited pro-fluoridation variables. Newspapers can be influential in shaping public policy opinions in the fight for community water fluoridation. © 2016 Wiley Periodicals, Inc.

  1. A calixarene-based ion-selective electrode for thallium(I) detection

    Energy Technology Data Exchange (ETDEWEB)

    Chester, Ryan [Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia); Sohail, Manzar [Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Locked Bag 4, Maroochydore DC, Queensland 4556 (Australia); Ogden, Mark I.; Mocerino, Mauro [Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia); Pretsch, Ernö [ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics (IBP), Universitätstrasse 16, CH-8092, Zürich (Switzerland); De Marco, Roland, E-mail: rdemarc1@usc.edu.au [Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia); Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Locked Bag 4, Maroochydore DC, Queensland 4556 (Australia)

    2014-12-03

    Highlights: • Tuning of metal binding cavities in thallium(I) calixarene ionophores. • Novel calixarene-based ionophores with improved selectivity for thallium(I). • Sandwich membrane characterization of thallium(I) binding in novel calixarenes. • Improved selectivity and sensitivity with novel thallium(I) calixarene ionophores. • Solid contact ion-selective electrodes for novel thallium(I) calixarene ionophores. - Abstract: Three new calixarene Tl{sup +} ionophores have been utilized in Tl{sup +} ion-selective electrodes (ISEs) yielding Nernstian response in the concentration range of 10{sup −2}–10{sup −6} M TlNO{sub 3} with a non-optimized filling solution in a conventional liquid contact ISE configuration. The complex formation constants (log β{sub IL}) for two of the calixarene derivatives with thallium(I) (i.e. 6.44 and 5.85) were measured using the sandwich membrane technique, with the other ionophore immeasurable due to eventual precipitation of the ionophore during these long-term experiments. Furthermore, the unbiased selectivity coefficients for these ionophores displayed excellent selectivity against Zn{sup 2+}, Ca{sup 2+}, Ba{sup 2+}, Cu{sup 2+}, Cd{sup 2+} and Al{sup 3+} with moderate selectivity against Pb{sup 2+}, Li{sup +}, Na{sup +}, H{sup +}, K{sup +}, NH{sub 4}{sup +} and Cs{sup +}, noting that silver was the only significant interferent with these calixarene-based ionophores. When optimizing the filling solution in a liquid contact ISE, it was possible to achieve a lower limit of detection of approximately 8 nM according to the IUPAC definition. Last, the new ionophores were also evaluated in four solid-contact (SC) designs leading to Nernstian response, with the best response noted with a SC electrode utilizing a gold substrate, a poly(3-octylthiophene) (POT) ion-to-electron transducer and a poly(methyl methacrylate)–poly(decyl methacrylate) (PMMA–PDMA) co-polymer membrane. This electrode exhibited a slope of 58.4 mV decade

  2. Fluoride and Water (For Parents)

    Science.gov (United States)

    ... toothpaste that carries the ADA's seal of acceptance. Brush babies' teeth as they come in with an infant toothbrush. ... locked cabinet. Also, supervise young kids when they brush their teeth to prevent swallowing of toothpaste or other fluoridated ...

  3. 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 (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.

  4. Thallium Flux Assay for Measuring the Activity of Monovalent Cation Channels and Transporters.

    Science.gov (United States)

    Weaver, C David

    2018-01-01

    Monovalent cation channels are critically important for physiological processes ranging from the control of neuronal excitability to the maintenance of solute balance. Mutations in these channels are associated with a multiplicity of diseases and monovalent cation channel-modulating drugs are used as therapeutics. Techniques that allow the measurement of the activity of these ion channels are useful for exploring their many biological roles as well as enabling the discovery and characterization of ion channel modulators for the purposes of drug discovery. Although there are numerous techniques for measuring the activity of monovalent cation channels, the thallium flux assay technique is a widely used fluorescence-based approach. Described herein is a method for using the thallium-flux technique for detecting and quantifying the activity of small-molecule potassium channel modulators in 384-well plates.

  5. The improved remineralization and fluoride uptake in vivo of triclosan/copolymer/sodium fluoride toothpaste vs. sodium fluoride toothpaste.

    Science.gov (United States)

    Zhang, Yun Po; Blake-Haskins, Jake; Din, Carol S; Gaffar, Abdul

    2003-01-01

    It has been shown that the twice-daily use of the triclosan/copolymer/sodium fluoride toothpaste can significantly reduce caries formation. The objective of this report was to review human studies comparing a triclosan/copolymer/sodium fluoride toothpaste to a placebo toothpaste (no fluoride), and a sodium fluoride toothpaste (positive control) for their ability to enhance remineralization of tooth enamel and increase the retention of fluoride by dental plaque for extended periods (up to 12 hours) after treatment. Two human plaque fluoride studies were conducted, measuring fluoride levels before brushing (baseline) and at two, six and twelve hours after brushing. An in situ enamel remineralization study, using microhardness measurements, was conducted as well. In the first study, the triclosan/copolymer/sodium fluoride toothpaste group was associated with a two-times increase of mean plaque fluoride as compared to the placebo control dentifrice. This increase was statistically significant at p < 0.05. In the second study, the triclosan/copolymer/sodium fluoride toothpaste group was associated with a 38% increase of mean plaque fluoride as compared to the sodium fluoride toothpaste group. This increase was statistically significant at p < 0.05. In the enamel remineralization study, the triclosan/copolymer/sodium fluoride toothpaste was significantly better (p < 0.05) than the sodium fluoride toothpaste (positive control) at promoting percent mineral recovery. The results obtained from the plaque fluoride studies and in situ remineralization study corroborated the findings of a recently completed two-year caries clinical study, which demonstrated that the triclosan/copolymer/sodium fluoride toothpaste provided superior cavity protection over the sodium fluoride toothpaste.

  6. Comparative studies on right ventricular pressure and volume overloading by thallium-201 myocardial scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Owada, K.; Tsukahara, Y.; Kijima, M.; Miyazaki, Y.; Ono, K. (Fukushima Medical Coll. (Japan))

    1982-03-01

    Thallium-201 myocardial scintigraphy was performed in 44 patients with various heart diseases including mitral stenosis, atrial septal defect, primary pulmonary hypertension, and left atrial myxoma. The morphological findings of right ventricular (RV) free wall on the scintigram and RV/IVS (interventricular septum) uptake ratio of the images obtained from the left anterior oblique projection were studied in the patients with RV pressure or volume overloading.

  7. Tunable frequency-stabilization of UV laser using a Hallow-Cathode Lamp of atomic thallium

    CERN Document Server

    Chen, Tzu-Ling; Shy, Jow-Tsong; Liu, Yi-Wei

    2013-01-01

    A frequency-stabilized ultraviolet laser system, locked to the thallium resonant transition of 377.5 nm, was demonstrated using a novel bichromatic spectroscopy technique for tuning the zero-crossing laser-lock point. The atomic thallium system is a promising candidate in atomic parity violation and permanent electric dipole moment experiments, and its 377.5 nm 6P1/2->7S1/2 transition is important for thallium laser cooling and trapping experiment. The pressure shift, owing to the high pressure bu?er gas of the hollow-cathode lamp, was observed using an atomic beam resonance as reference. Such a shift was corrected by adjusting the peak ratio of the two Doppler-free saturation pro?les resulted from two pumping beams with a 130 MHz frequency di?erence. The resulted frequency stability of the ultraviolet laser is ?0.5 MHz at 0.1 sec integration time. This scheme is compact and versatile for stabilizing UV laser systems, which acquire a sub-MHz stability and frequency tunability.

  8. Detection of human collateral circulation by vasodilation-thallium-201 tomography

    Energy Technology Data Exchange (ETDEWEB)

    Nienaber, C.A.; Salge, D.; Spielmann, R.P.; Montz, R.; Bleifeld, W. (University Hospital Eppendorf, Hamburg (Germany, F.R.))

    1990-04-15

    Coronary arteriolar vasodilation may provoke redistribution of flow to collateral-dependent jeopardized myocardium. To assess the physiologic significance of collaterals, 80 consecutive post-infarction patients (age 58 +/- 8 years) underwent vasodilation-redistribution thallium-201 tomographic imaging after administration of 0.56 mg of intravenous dipyridamole/kg body weight. Circumferential profile analysis of thallium-201 uptake and redistribution in representative left ventricular tomograms provided quantitative assessment of transient and fixed defects and separation between periinfarctional and distant inducible hypoperfusion. Tomographic perfusion data were correlated to wall motion and collateral circulation between distinct anatomic perfusion territories. Patients were grouped according to presence (59%) or absence (41%) of angiographically visible collateral channels to jeopardized myocardium. In the presence of collaterals, distant reversible defects were larger than in absence of collaterals (p less than 0.05); the extent of combined periinfarctional and distant redistribution was also larger in collateralized patients (p less than 0.025), whereas the size of the persistent perfusion defect was similar in both groups. By prospective analysis the tomographic perfusion pattern of combined periinfarctional and distant redistribution revealed a sensitivity of 85% and a specificity of 78% for the detection of significant collateral circulation in this group of patients. Thus, using the exhausted flow reserve as a diagnostic tool, vasodilation-thallium-201 tomography has the potential to identify and quantitate collateralized myocardium in post-infarction patients and may guide diagnostic and therapeutic decision-making.

  9. [Characterization of kale (Brassica oberacea var acephala) under thallium stress by in situ attenuated total reflection FTIR].

    Science.gov (United States)

    Yao, Yan; Zhang, Ping; Wang, Zhen-Chun; Chen, Yong-Heng

    2009-01-01

    The experiment was designed based on consumption of carbon dioxide through the photosynthesis of Brassica oberacea var acephala leaf, and the photosynthesis of kale leaf under thallium stress was investigated by in situ attenuated total reflection FTIR (in situ ATR-FTIR). The ATR-FTIR showed that the absorption peaks of leaves had no obvious difference between plants growing in thallium stress soil and plants growing in non-thallium pollution soil, and the strong peaks at 3,380 cm(-1) could be assigned to the absorption of water, carbohydrate, protein or amide; the strong peaks at 2,916 and 2,850 cm(-1) assigned to the absorption of carbohydrate or aliphatic compound; the peaks at 1,640 cm(-1) assigned to the absorption of water. However, as detected by the in situ ATR-FTIR, the double peaks (negative peaks) at 2,360 and 2,340 cm(-1) that are assigned to the absorption of CO2 appeared and became high gradually. It was showed that kale was carrying photosynthesis. At the same time, the carbon dioxide consumption speed of leaf under thallium stress was obviously larger than that of the blank It was expressed that photosynthesis under thallium stress was stronger than the blank All these represented that kale had certain tolerance to the heavy metal thallium. Meanwhile, the carbon dioxide consumption of grown-up leaf was more than that of young leaf whether or not under thallium stress. It was also indicated that the intensity of photosynthesis in grown-up leaf is higher than that in young leaf.

  10. 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

  11. Chronic Fluoride Toxicity: Dental Fluorosis

    Science.gov (United States)

    DenBesten, Pamela; Li, Wu

    2012-01-01

    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/mineral 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 doserelated decrease in cycles of ameloblast modulation from ruffleended 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

  12. Fluoride content of tank water in Australia.

    Science.gov (United States)

    Cochrane, N J; Hopcraft, M S; Tong, A C; Thean, H l; Thum, Y S; Tong, D E; Wen, J; Zhao, S C; Stanton, D P; Yuan, Y; Shen, P; Reynolds, E C

    2014-06-01

    The aims of this study were to: (1) analyse the fluoride content of tank water; (2) determine whether the method of water collection or storage influenced fluoride content; and (3) survey participant attitudes towards water fluoridation. Plastic tubes and a questionnaire were distributed through dentists to households with water tanks in Victoria. A midstream tank water sample was collected and fluoride analysed in triplicate using ion chromatography All samples (n = 123) contained negligible amounts of fluoride, with a mean fluoride concentration of fluoride content and variables investigated such as tank material, tank age, roof material and gutter material. Most people did not know whether their tank water contained fluoride and 40.8% preferred to have access to fluoridated water. The majority thought fluoride was safe and more than half of the respondents supported fluoridation. Fluoride content of tank water was well below the optimal levels for caries prevention. People who rely solely on tank water for drinking may require additional exposure to fluoride for optimal caries prevention. © 2014 Australian Dental Association.

  13. Water Fluoridation Reporting System (Public Water Systems)

    Data.gov (United States)

    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...

  14. Thallium and manganese complexes involved in the luminescence emission of potassium-bearing aluminosilicates

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Gonzalez, Miguel A., E-mail: miguel.gomez@mncn.csic.es [Museo Nacional de Ciencias Naturales, CSIC, Jose Gutierrez Abascal 2, Madrid E-28006 (Spain); Garcia-Guinea, Javier, E-mail: guinea@mncn.csic.es [Museo Nacional de Ciencias Naturales, CSIC, Jose Gutierrez Abascal 2, Madrid E-28006 (Spain); Garrido, Fernando, E-mail: fernando.garrido@mncn.csic.es [Museo Nacional de Ciencias Naturales, CSIC, Jose Gutierrez Abascal 2, Madrid E-28006 (Spain); Townsend, Peter D., E-mail: pdtownsend@gmail.com [School of Science and Technology, University of Sussex, Brighton BN1 9QH (United Kingdom); Marco, Jose-Francisco, E-mail: jfmarco@iqfr.csic.es [Instituto de Química-Física Rocasolano, CSIC, Calle Serrano 119, Madrid E-28006 (Spain)

    2015-03-15

    The luminescence emission at 285 nm in natural K-feldspar has been studied by Russian groups and associated with thallium ions in structural positions of K{sup +} sites as artificially thallium-doped feldspars display the same emission band. Here attention is focussed on spectra of CL emission bands centered near 285 and 560 nm from paragenetic adularia, moscovite and quartz micro-inclusions. With accesorial thallium they show clear resemblances to each other. Associated sedimentary and hydrothermal aluminosilicate samples collected from Guadalix (Madrid, Spain) were analyzed with a wide range of experimental techniques including Environmental Scanning Electron Microscopy (ESEM) with an attached X-Ray Energy-Dispersive Spectrometer (EDS) and a cathodoluminescence probe (CL) and Electron Probe Microanalysis (EPMA), X-Ray Fluorescence Spectrometry (XRF), Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES), Differential and Thermogravimetric Analyses (DTA-TG), radioluminescence (RL), Mössbauer spectroscopy and X-Ray Photoelectron Spectrometry (XPS). The luminescence emission bands at 285 and 560 nm seem to be associated with hydrous thallium–manganese complexes bonded to potassium-bearing aluminosilicates since various minerals such as K-feldspar, moscovite and quartz micro-inclusions display similar CL spectra, accesorial thallium and hydroxyl groups. The presence of iron introduces a brown color which is attributed to submicroscopic iron oxides detectable in the optical and chemical microanalysis, but this does not contribute to the luminescence emission. The XPS Mn 2p spectrum of the adularia sample at room temperature is composed of a spin–orbit doublet plus clear shake-up satellite structure ∼4 eV above the main photoemision lines and is consistent with Mn{sup 2+} in good agreement with the observed luminescence emission at 560 nm for aluminosilicates produced by a {sup 4}T1({sup 4}G)→{sup 6}A1({sup 6}S) transition in tetrahedrally

  15. Diagnostic value of 123I-phenylpentadecanoic acid (IPPA) metabolic and thallium 201 perfusion imaging in stable coronary artery disease.

    Science.gov (United States)

    Walamies, M; Turjanmaa, V; Koskinen, M; Uusitalo, A

    1993-08-01

    The diagnostic value of 123I-phenylpentadecanoic acid (IPPA) metabolic cardiac imaging was studied in a group (n = 29) of patients with angiographically confirmed CAD using single photon emission computed tomography (SPECT). A symptom-limited exercise test was first done with IPPA, and 2 days later with thallium. Medications were not withheld during testing. Fourteen healthy control subjects participated in parallel IPPA and 15 in thallium tests. Data acquisition and output were comparable in the two imaging modalities. By testing various relatively simple criteria for abnormality we found that the semiquantitative interpretation was more accurate than the visual readings. The best compromise of accuracy with the scored criteria consisted of a sensitivity of 86% and a specificity of 86%, obtained with IPPA polar tomograms (mild exercise defect) and a sensitivity of 86% and a specificity of 80% obtained with thallium (regionally decreased washout). With visual interpretation alone, a sensitivity of 83% and a specificity of 71% was detected with IPPA (mild exercise defect) and 72% and 73%, respectively, with thallium (partial reversibility). The sensitivity of the exercise ECG alone was 62%. The results of this study imply that IPPA imaging could be a rational, uncomplicated clinical method for non-invasive diagnosis of CAD. The diagnostic ability of IPPA is at least as good as that of thallium, and it is possible to use them in succession.

  16. Dilatation of the left ventricular cavity on dipyridamole thallium-201 imaging: A new marker of triple-vessel disease

    Energy Technology Data Exchange (ETDEWEB)

    Takeishi, Y.; Tono-oka, I.; Ikeda, K.; Komatani, A.; Tsuiki, K.; Yasui, S. (Yamagata Univ. School of Medicine (Japan))

    1991-02-01

    To investigate the significance and mechanism of dilatation of the left ventricular cavity on dipyridamole thallium-201 imaging, we performed both dipyridamole thallium-201 imaging and dipyridamole radionuclide angiography on 83 patients with known angiograms. The dipyridamole/delayed ratio of the left ventricular dimension from the thallium-201 image was defined as the left ventricular dilatation ratio (LVDR). An LVDR greater than the mean + two standard deviations in patients without coronary artery disease was defined as abnormal. Twenty-two of 83 patients showed an abnormal LVDR, and 18 of the 22 patients (82%) had triple-vessel disease. By defect and washout analysis, the sensitivity and specificity for correctly identifying the patients as having triple-vessel disease was 72% and 76%, respectively, whereas LVDR had a sensitivity of 72% and a specificity of 93%. When LVDR was used in combination with the defect and washout criteria, sensitivity increased to 84% without a loss of specificity. In those 22 patients with abnormal LVDRs, end-diastolic volume measured by radionuclide angiography did not change after dipyridamole infusion. Dilatation of the left ventricular cavity on dipyridamole thallium-201 imaging reflected relative subendocardial hypoperfusion induced by dipyridamole rather than actual chamber enlargement. The LVDR was moderately sensitive and highly specific for triple-vessel disease and provided complementary information to dipyridamole thallium-201 imaging.

  17. High-fluoride groundwater.

    Science.gov (United States)

    Rao, N Subba

    2011-05-01

    Fluoride (F(-)) is essential for normal bone growth, but its higher concentration in the drinking water poses great health problems and fluorosis is common in many parts of India. The present paper deals with the aim of establishment of facts of the chemical characteristics responsible for the higher concentration of F(-) in the groundwater, after understanding the chemical behavior of F(-) in relation to pH, total alkalinity (TA), total hardness (TH), carbonate hardness (CH), non-carbonate hardness (NCH), and excess alkalinity (EA) in the groundwater observed from the known areas of endemic fluorosis zones of Andhra Pradesh that have abundant sources of F(-)-bearing minerals of the Precambrians. The chemical data of the groundwater shows that the pH increases with increase F(-); the concentration of TH is more than the concentration of TA at low F(-) groundwater, the resulting water is represented by NCH; the TH has less concentration compared to TA at high F(-) groundwater, causing the water that is characterized by EA; and the water of both low and high concentrations of F(-) has CH. As a result, the F(-) has a positive relation with pH and TA, and a negative relation with TH. The operating mechanism derived from these observations is that the F(-) is released from the source into the groundwater by geochemical reactions and that the groundwater in its flowpath is subjected to evapotranspiration due to the influence of dry climate, which accelerates a precipitation of CaCO(3) and a reduction of TH, and thereby a dissolution of F(-). Furthermore, the EA in the water activates the alkalinity in the areas of alkaline soils, leading to enrichment of F(-). Therefore, the alkaline condition, with high pH and EA, and low TH, is a more conducive environment for the higher concentration of F(-) in the groundwater.

  18. 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)

  19. Fluoride in African groundwater: Occurrence and mitigation

    NARCIS (Netherlands)

    Vasak, S.; Griffioen, J.; Feenstra, L.

    2010-01-01

    Fluoride in groundwater has both natural and anthropogenic sources. Fluoride bearing minerals, volcanic gases and various industrial and agricultural activities can contribute to high concentrations. High intake of fluoride from drinking water is the main cause of fluorosis and may lead to many

  20. Fluoride: its role in dentistry

    Directory of Open Access Journals (Sweden)

    Livia Maria Andaló Tenuta

    2010-01-01

    Full Text Available In spite of decades of research on fluoride and the recognition of its role as the cornerstone of dental caries reduction in the last fifty years, questions still arise on its use at community, self-applied and professional application levels. Which method of fluoride delivery should be used? How and when should it be used? How can its benefits be maximized and still reduce the risks associated with its use? These are only some of the challenging questions facing us daily. The aim of this paper is to present scientific background to understand the importance of each method of fluoride use considering the current caries epidemiological scenario, and to discuss how individual or combined methods can be used based on the best evidence available.

  1. METHOD OF PREPARING METAL FLUORIDES

    Science.gov (United States)

    Katz, J.J.; Sheft, I.

    1959-08-11

    A method is presented for preparing the halides of elements which are relatively non-reactive with halogenating agents. The method involves reacting a mixture of an oxygen containing salt of a difficulty halogenated metal with an oxygen containing salt of an easily halogenated metal with a halogenating agent. Accordingly plutonium tetrafluoride is produced by reacting a mixture of plutonium dioxide and uranium octaoxide with bromine trifluoride. The reaction proceeds smoothly at moderate temperatures and the resulting plutonium trifluoride may be readily separated from many impurities which form volatile fluorides by volatilizing these volatile fluorides from the reaction chamber.

  2. fluoride iontophoresis versus topical fluoride application in the ...

    African Journals Online (AJOL)

    Material and Methods: Test teeth received a 2% neutral solution of sodium fluoride using Desensitron I1 Iontophoresis device with current and the control teeth received the solution on the device without current. Thirteen patients comprising eight females and five males who complained of tooth hypersensitivity participated ...

  3. Fluoride Iontophoresis Versus Topical Fluoride Application In The ...

    African Journals Online (AJOL)

    Material and Methods: Test teeth received a 2% neutral solution of sodium fluoride using Desensitron II Iontophoresis device with current and the control teeth received the solution on the device without current. Thirteen patients comprising eight females and five males who complained of tooth hypersensitivity participated in ...

  4. A preliminary investigation and evaluation of the thallium environmental impacts of the unmined Xiangquan thallium-only deposit in Hexian, China

    Science.gov (United States)

    Zhou, Taofa; Fan, Yu; Yuan, Feng; Cooke, David; Zhang, Xin; Li, Liangjun

    2008-03-01

    The Xiangquan Thallium-only deposit in Hexian, east China is a newly found near-surface and unmined shallow-seated thallium deposit. The 250t Tl deposit is hosted in Lower Ordovician Lunshan Group as lenticular and confined by northeast F1, F2 faults. The metallic minerals are dominated by pyrite, more than 95% Tl occurs in pyrite as tiny individual grains or as ‘‘invisible thallium”. Tl and other trace elements pollution in ecosystems such as soils, surface and ground waters and water sediments, plants and crops, and animal and human beings in Xiangquan near the Tl ore deposit have been investigated and evaluated. Results show that Tl as well as As and Sb in ecosystems in Xiangquan around the deposit have enriched, they came from Tl-pyrite in the ore bodies and in the parent rocks of weathered soils on top of the ore bodies and went into the nearby ecosystems through weathering, leaching and dissolving. In 2 km2 around the Xiaolongwang Mountain where the Tl ore deposit seated, soils, vegetables, crops have been polluted or heavily polluted by Tl, As and Sb. Farmlands near the ore body are not fit to grow vegetables and crops. Thermal Spring water in Xiangquan town and pond water close to the Tl deposit are not potable. Tl also enriches in human hair and urinate of villagers who live close to the Tl deposit. Even through the Tl-only deposit has put clear environmental impacts on the local environment and ecosystems around it, no serious consequences of Tl pollution have so far taken place due to unmining of the Tl deposit as well as the screen effect of the silicficious breccia cap on top of it. All this work adds new knowledge to understand Tl behavior in unmined Tl deposit, and also benefit to the local environmental protection and the future mineral resources exploration.

  5. Fluoridering af drikkevandet i Danmark?

    DEFF Research Database (Denmark)

    Arvin, Erik; Spliid, Henrik; Bruvo, M.

    2010-01-01

    -tilsætning til drikkevandet (fluoridering). Siden da er emnet ikke taget op. Formålet med dette indlæg er at besvare spørgsmålene: 1. Er der behov for fluoridering af drikkevandet i Danmark? 2. Er der alternativer? Hvordan påvirker blødgøring af vand og andre vandbehandlingsmetoder dental caries hos børn og unge...... drikkevandet. Blødgøring af vand er kommet på dagsordenen i den danske vandsektor. Teknikken vil medføre adskillige fordele for forbrugerne, men uden supplerende fluoridering af drikkevandet vil forekomsten af dental caries hos børn og unde stige. Hvis man f.eks. fjerner 80 mg/l calcium fra drikkevandet gennem...... blødgøringen skal man supplere med tilsætning af ca. 0,5 mg/l af fluorid for at processen er dental caries neutral. Det er næsten dobbelt så meget som der i forvejen er i drikkevandet mange steder i Danmark....

  6. Special Report: Fluoridation of Water.

    Science.gov (United States)

    Hileman, Bette

    1988-01-01

    Reviews the controversy regarding water fluoridation in the United States during the last 50 years. Discusses the current status; benefits; and health risks including skeletal fluorosis, kidney disease, hypersensitivity, mutagenic effects, birth defects, and cancer. Presents statistics and anecdotal accounts. (CW)

  7. Musculoskeletal imaging using fluoride PET.

    Science.gov (United States)

    Fischer, Dorothee Rita

    2013-11-01

    The convenience of (18)F-fluoride imaging is undeniable both because of its favorable tracer and because of its technical characteristics, including high image quality and short examination times leading to increased patient comfort. Depending on the activity administered, the radiation dose to patients is about comparable to higher using (18)F-fluoride for bone imaging compared with conventional scintigraphy using 99mTc-methylene diphosphonate. In times of molybdenum shortage, (18)F-fluoride represents a good alternative to 99mTc-based bone tracers. Besides malignant skeletal disease(18)F-fluoride PET/CT has in the last decade been investigated in a variety of non-oncologic musculoskeletal disorders of all parts of the skeleton. Studies included imaging of the skull with a special focus on bisphosphonate-induced osteonecrosis of the jaw in patients treated with bisphosphonates due to benign or malignant bone changes. Further studies evaluated the appendicular skeleton with emphasis on postsurgical changes including patients after knee and hip surgery and patients having received bone grafts of their limbs. Also, therapeutic effect of (18)F-fluoride PET/CT on patients with unclear foot pain was investigated. Finally imaging of the axial skeleton was analyzed including patients with ankylosing spondylitis and with Paget disease as well as patients after spine surgery including assessment of cage incorporation after cervical and lumbar spine fusion surgery. Furthermore, children suspected of child abuse as well as young patients with back pain were investigated by either (18)F-fluoride PET or PET/CT. Regarding its favorable technical aspects as well as study results presented, it is imaginable that (18)F-fluoride PET/(CT) will be increasingly used for non-oncologic musculoskeletal imaging in the future either as an adjunct or alternative to so far established imaging modalities and seems to be promising regarding decision making in the therapeutic management of

  8. {sup 201}Thallium SPECT, accuracy in astrocytoma diagnosis and treatment evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Kaellen, K

    1999-10-01

    The aims of the studies included in this thesis were: - to investigate the reliability of {sup 201}Thallium single photon emission computed tomography. Tl SPECT for preoperative diagnosis and histological staging of malignant astrocytomas in comparison with CT; - to develop a method for quantification of cerebral thallium uptake, and to evaluate the quantitative measurement in comparison with CT, for astrocytoma treatment follow-up purposes; - to compare quantitative Tl SPECT and proton magnetic resonance spectroscopy (H-MRS) with conventional MR imagingfor astrocytoma monitoring, and to evaluate associations between change of morphological tumour characteristics during treatment and changes of cerebral thallium uptake and metabolic ratios. Results and conclusions: - High TI-index, calculated as a ratio comparing tumour uptake to uptake in the contralateral hemisphere, is an indicator of highly malignant astrocytoma. Differentiation between the high-grade astrocytomas, the low-grade astrocytomas, and infectious lesions is only partial, with an overlap of Tl-indexes between these groups. High-grade astrocytomas that do not show contrast enhancement on CT, and astrocytomas with central necrosis and moderate ring-enhancement, tend to be underestimated when evaluated by Tl-index calculation. Tl SPECT is not a reliable method for non-invasive tumour staging among the group of highly malignant astrocytomas. - Quantification of cerebral TI-uptake, defining the volume of viable tumour tissue, is a new method for astrocytoma chemotherapy monitoring. Results suggest that the method provides prognostic information, and information of treatment efficacy, at an earlier stage than CT. - We did not find a higher accuracy of quantitative Tl SPECT than of MR for monitoring purposes and our results indicated that treatment induced MR changes were interrelated with TI-uptake variations. - Multi-voxel H-MRS was difficult to apply for astrocytoma treatment monitoring, due to the

  9. A Novel Ion - selective Polymeric Membrane Sensor for Determining Thallium(I) With High Selectivity

    Science.gov (United States)

    Kassim, Anuar; Rezayi, Majid; Ahmadzadeh, Saeid; Rounaghi, Gholamhossein; Mohajeri, Masoomeh; Azah Yusof, Noor; Tee, Tan Wee; Yook Heng, Lee; Halim Abdullah, Abd

    2011-02-01

    Thallium is a toxic metal that introduced into the environment mainly as a waste from the production of zinc, cadmium, and lead and by combustion of coal. Thallium causes gastrointestinal irritation and nerve damage when people are exposed to it for relatively short period of time. For long term, thallium has the potential to cause the following effects: change in blood chemistry, damage to liver, kidney, intestinal and testicular tissue, and hair loss. In this work a membrane was prepared by use of 4'-nitrobenzo -18-crown-6 (4'NB18C6) as an ion carrier, polyvinylchloride (PVC) as a matrix, and diocthylphetalate (DOP) as a plasticizer for making an ion selective electrode for measurement of Tl+ cation in solutions. The amount of 4'-nitrobenzo-18C6 and polyvinylchloride were optimized in the preparation of the membrane. The response of the electrode was Nernstian within the concentration range 1.0 × 10-8 to 1.0 × 10-1M. This sensor displays a drift in Nernstian response for this cation with increasing the amount of ionophore and decreasing the amount of polyvinylchloride.The results of potentiometric measurements showed that, this electrode also responses to Cu2+ Ni2+ and Pb2+ cations, but the electrode has a wider dynamic range and a lower detection limit to Tl+ cation. The effects of various parameters such as pH, different cations interferences, effect of the amount of ionophore and polyvinylchloride and time on response of the coated ion selective electrode were investigated. Finally the constructed electrode was used in complexometric and precipitation titrations of Tl+ cation with EDTA and KBr, respectively. The response of the fabricated electrode at concentration range from 1.0 × 10-8 to 1.0 × 10-1M is linear with a Nernstian slope of 57.27 mV.

  10. Oxidative stress and DNA damage in broad bean (Vicia faba L.) seedlings induced by thallium.

    Science.gov (United States)

    Radić, Sandra; Cvjetko, Petra; Glavas, Katarina; Roje, Vibor; Pevalek-Kozlina, Branka; Pavlica, Mirjana

    2009-01-01

    Thallium (Tl) is a metal of great toxicological concern because it is highly toxic to all living organisms through mechanisms that are yet poorly understood. Since Tl is accumulated by important crops, the present study aimed to analyze the biological effects induced by bioaccumulation of Tl in broad bean (Vicia faba L.) as well as the plant's antioxidative defense mechanisms usually activated by heavy metals. Thallium toxicity was related to production of reactive oxygen species in leaves and roots of broad bean seedlings following short-term (72 h) exposure to thallium (I) acetate (0, 0.5, 1, 5, and 10 mg/L) by evaluating DNA damage and oxidative stress parameters as well as antioxidative response. The possible antagonistic effect of potassium (K) was tested by combined treatment with 5 mg/L of Tl (Tl+) and 10 mg/L of potassium (K+) acetate. Accumulation of Tl+ in roots was 50 to 250 times higher than in broad bean shoots and was accompanied by increase in dry weight and proline. Despite responsive antioxidative defense (increased activities of superoxide dismutase, ascorbate peroxidase, and pyrogallol peroxidase), Tl+ caused oxidative damage to lipids and proteins as evaluated by malondialdehyde and carbonyl group levels, and induced DNA strand breaks. Combined treatment caused no oxidative alternations to lipids and proteins though it induced DNA damage. The difference in Tl-induced genotoxicity following both acellular and cellular exposure implies indirect DNA damage. Results obtained indicate that oxidative stress is involved in the mechanism of Tl toxicity and that the tolerance of broad bean to Tl is achieved, at least in part, through the increased activity of antioxidant enzymes.

  11. Thallium Intoxication Treated with Long-Term Hemodialysis, Forced Diuresis and Prussian Blue

    DEFF Research Database (Denmark)

    Larsen, Elfinn; Solgaard, Per Bent; Freund, L. Gade

    1978-01-01

    A 56 yr old woman, who ingested 2 g of thallium sulfate, was successfully treated with long-term hemodialysis for 200 h during 10 days, combined with forced diuresis and Prussian blue. The effect of the artificial kidney dialysis was determined by repeated analysis of the Tl concentration...... in the dialysis bath and in blood samples. During the 1st 120 h of hemodialysis, 143 mg of Tl was eliminated via the artificial kidney and 110 mg via the urinary tract. The present case of acute Tl intoxication is the 1st in which long-term hemodialysis has been used in the acute phase...

  12. Experimental excitation functions of deuteron induced reactions on natural thallium up to 50 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Adam Rebeles, R., E-mail: radamreb@vub.ac.be [Cyclotron Laboratory, Vrije Universiteit Brussel, B-1090 Brussels (Belgium); Van den Winkel, P.; Hermanne, A. [Cyclotron Laboratory, Vrije Universiteit Brussel, B-1090 Brussels (Belgium); Tarkanyi, F.; Takacs, S. [Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen H-4026 (Hungary)

    2012-10-01

    Excitation functions of deuteron induced reactions on natural thallium leading to the formation of {sup 204m,203m2+m1+g,202m,201m+g,200}Pb and {sup 202,201m+g,200m+g}Tl isotopes were determined up to 50 MeV. The cross sections were measured by an activation technique using stacked foil irradiation. The excitation functions of the investigated reactions are compared with data reported in literature and also with the theoretical results of TALYS nuclear reaction code. From the measured cross section data, the thick target yield for the medical interesting {sup 203}Pb isotope is calculated.

  13. 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

    toothpaste. The fluoride content in the piped drinking water was 0.5 mg F/L. Main outcome measure: Urinary fluoride excretion. Results: The 24-hour urinary fl uoride excretion/kg body weight varied from 0.014 mg F for the placebo intervention and non-fluoride toothpaste to 0.027 mg F for the 0.375 mg.......05). Conclusions: All sources of fluoride must be considered when designing community programs. With 0.5 mg F/L in the drinking water and daily use of fluoride toothpaste, most children had a fluoride intake optimal for dental health. In this setting, additional intake of fluoride milk was within safe limits up......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...

  14. Focus on fluorides: update on the use of fluoride for the prevention of dental caries.

    Science.gov (United States)

    Carey, Clifton M

    2014-06-01

    Improving the efficacy of fluoride therapies reduces dental caries and lowers fluoride exposure. Fluoride is delivered to the teeth systemically or topically to aid in the prevention of dental caries. Systemic fluoride from ingested sources is in blood serum and can be deposited only in teeth that are forming in children. Topical fluoride is from sources such as community water, processed foods, beverages, toothpastes, mouthrinses, gels, foams, and varnishes. The United States Centers for Disease Control and Prevention (CDC) and the American Dental Association (ADA) have proposed changes in their long standing recommendations for the amount of fluoride in community drinking water in response to concerns about an increasing incidence of dental fluorosis in children. Current research is focused on the development of strategies to improve fluoride efficacy. The purpose of this update is to inform the reader about new research and policies related to the use of fluoride for the prevention of dental caries. Reviews of the current research and recent evidence based systematic reviews on the topics of fluoride are presented. Topics discussed include: updates on community water fluoridation research and policies; available fluoride in dentifrices; fluoride varnish compositions, use, and recommendations; and other fluoride containing dental products. This update provides insights into current research and discusses proposed policy changes for the use of fluoride for the prevention of dental caries. The dental profession is adjusting their recommendations for fluoride use based on current observations of the halo effect and subsequent outcomes. The research community is focused on improving the efficacy of fluoride therapies thus reducing dental caries and lowering the amount of fluoride required for efficacy. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Focus on Fluorides: Update on the Use of Fluoride for the Prevention of Dental Caries

    Science.gov (United States)

    Carey, Clifton M.

    2014-01-01

    Declarative Title: Improving the efficacy of fluoride therapies reduces dental caries and lowers fluoride exposure. Background Fluoride is delivered to the teeth systemically or topically to aid in the prevention of dental caries. Systemic fluoride from ingested sources is in blood serum and can be deposited only in teeth that are forming in children. Topical fluoride is from sources such as community water, processed foods, beverages, toothpastes, mouthrinses, gels, foams, and varnishes. The United States Centers for Disease Control and Prevention (CDC) and the American Dental Association (ADA) have proposed changes in their long standing recommendations for the amount of fluoride in community drinking water in response to concerns about an increasing incidence of dental fluorosis in children. Current research is focused on the development of strategies to improve fluoride efficacy. The purpose of this update is to inform the reader about new research and policies related to the use of fluoride for the prevention of dental caries. Methods Reviews of the current research and recent evidence based systematic reviews on the topics of fluoride are presented. Topics discussed include: updates on community water fluoridation research and policies; available fluoride in dentifrices; fluoride varnish compositions, use, and recommendations; and other fluoride containing dental products. This update provides insights into current research and discusses proposed policy changes for the use of fluoride for the prevention of dental caries. Conclusions The dental profession is adjusting their recommendations for fluoride use based on current observations of the halo effect and subsequent outcomes. The research community is focused on improving the efficacy of fluoride therapies thus reducing dental caries and lowering the amount of fluoride required for efficacy. PMID:24929594

  16. Fluoride retention in saliva and in dental biofilm after different home-use fluoride treatments

    Directory of Open Access Journals (Sweden)

    Daniela Correia Cavalcante SOUZA

    2014-08-01

    Full Text Available This single-blind, randomized, crossover study aimed at assessing the long-term fluoride concentrations in saliva and in dental biofilm after different home-use fluoride treatments. The study volunteers (n = 38 were residents of an area with fluoridated drinking water. They were administered four treatments, each of which lasted for one week: twice-daily placebo dentifrice, twice-daily fluoride dentifrice, twice-daily fluoride dentifrice and once-daily fluoride mouthrinse, and thrice-daily fluoride dentifrice. At the end of each treatment period, samples of unstimulated saliva and dental biofilm were collected 8 h after the last oral hygiene procedure. Fluoride concentrations in saliva and dental biofilm were analyzed using a specific electrode. The fluoride concentrations in saliva and dental biofilm 8 h after the last use of fluoride products did not differ among treatments. The results of this study suggest that treatments with home-use fluoride products have no long-term effect on fluoride concentrations in saliva and in dental biofilm of residents of an area with a fluoridated water supply.

  17. Fluoride retention in saliva and in dental biofilm after different home-use fluoride treatments.

    Science.gov (United States)

    Souza, Daniela Correia Cavalcante; Maltz, Marisa; Hashizume, Lina Naomi

    2014-01-01

    This single-blind, randomized, crossover study aimed at assessing the long-term fluoride concentrations in saliva and in dental biofilm after different home-use fluoride treatments. The study volunteers (n = 38) were residents of an area with fluoridated drinking water. They were administered four treatments, each of which lasted for one week: twice-daily placebo dentifrice, twice-daily fluoride dentifrice, twice-daily fluoride dentifrice and once-daily fluoride mouthrinse, and thrice-daily fluoride dentifrice. At the end of each treatment period, samples of unstimulated saliva and dental biofilm were collected 8 h after the last oral hygiene procedure. Fluoride concentrations in saliva and dental biofilm were analyzed using a specific electrode. The fluoride concentrations in saliva and dental biofilm 8 h after the last use of fluoride products did not differ among treatments. The results of this study suggest that treatments with home-use fluoride products have no long-term effect on fluoride concentrations in saliva and in dental biofilm of residents of an area with a fluoridated water supply.

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

    Science.gov (United States)

    Olympio, Kelly Polido Kaneshiro; Cardoso, Vanessa Eid da Silva; Bijella, Maria Fernanda Borro; Pessan, Juliano Pelim; Delbem, Alberto Carlos Botazzo; Buzalaf, Marília Afonso Rabelo

    2009-01-01

    This study evaluated the bioavailability of fluoride after topical application of a dual-fluoride varnish commercially available in Brazil, when compared to Duraphat. 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). After 1-month interval (phase II), the same amount (0.2 mL) of the fluoride varnish Duraphat (2.26% fluorine, sodium fluoride, Colgate) 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 (papplication of Duraphat caused a transitory increase in the urinary fluoride output, returning to baseline levels 48 h after its use. The tested varnish formulation, which has been shown to be effective in in vitro studies, also can be considered safe.

  19. Application of Hyphenated Techniques in Speciation Analysis of Arsenic, Antimony, and Thallium

    Science.gov (United States)

    Michalski, Rajmund; Szopa, Sebastian; Jabłońska, Magdalena; Łyko, Aleksandra

    2012-01-01

    Due to the fact that metals and metalloids have a strong impact on the environment, the methods of their determination and speciation have received special attention in recent years. Arsenic, antimony, and thallium are important examples of such toxic elements. Their speciation is especially important in the environmental and biomedical fields because of their toxicity, bioavailability, and reactivity. Recently, speciation analytics has been playing a unique role in the studies of biogeochemical cycles of chemical compounds, determination of toxicity and ecotoxicity of selected elements, quality control of food products, control of medicines and pharmaceutical products, technological process control, research on the impact of technological installation on the environment, examination of occupational exposure, and clinical analysis. Conventional methods are usually labor intensive, time consuming, and susceptible to interferences. The hyphenated techniques, in which separation method is coupled with multidimensional detectors, have become useful alternatives. The main advantages of those techniques consist in extremely low detection and quantification limits, insignificant interference, influence as well as high precision and repeatability of the determinations. In view of their importance, the present work overviews and discusses different hyphenated techniques used for arsenic, antimony, and thallium species analysis, in different clinical, environmental and food matrices. PMID:22654649

  20. Evaluation of myocardial abnormalities in collagen diseases by thallium-201 myocardial scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Yamano, Shigeru; Kagoshima, Tadashi; Sugihara, Kiyotaka (Nara Medical Univ., Kashihara (Japan)) (and others)

    1993-12-01

    This study was performed to evaluate myocardial abnormalities in patients with collagen diseases by exercise and rest thallium-201 myocardial scintigrams. A total of 65 patients without ischemic ECG changes, consisting of 18 with systemic lupus erythematosus (SLE), 18 with polymyositis (PM), 8 with progressive systemic sclerosis (PSS), and 21 with Sjoegren's syndrome (SjS), was enrolled in this study. Reversible exercise-induced defects scintigraphically suggesting myocardial ischemia were noted in 8 cases of SLE, 4 cases of PM, 4 cases of PSS, and 3 cases of SjS. Nineteen patients had exercise-induced defects and underwent cardiac catheterization, 8 of whom had normal coronary angiograms. Fixed hypoperfusion areas were observed in one case of SLE, 6 cases of PM and 3 cases of SjS. Rest thallium-201 myocardial scintigram disclosed hypoperfusion areas which were not induced by exercise in 2 cases of SLE, 3 cases of PM, one case of PSS and 5 cases of SjS. Echocardiogram showed no significant differences in ejection fraction and % fractional shortening between the disease groups and healthy control group. These findings suggest that patients with collagen diseases have abnormalities of coronary circulation at the level of the intramural vasculature before cardiac function impairment, myocardial fibrosis and functional abnormalities at the cell membrane. (author).

  1. Follow-up Thallium-201 scintigraphy after mantle field radiotherapy for Hodgkin's disease

    Energy Technology Data Exchange (ETDEWEB)

    Pierga, J.Y.; Girinski, T.; Henry-Amar, M. (Institut Gustave Roussy, Villejuif (France)); Maunoury, C.; Valette, H.; Tchernia, G.; Desgrez, A. (Centre Hospitalier de Bicetre, Le Kremlin-Bicetre (France)); Socie, G. (Institut Gustave Roussy, Villejuif (France) Hopital St Louis, Paris (France)); Cosset, J.M. (Institut Gustave Roussy, Villejuif (France) Institut Curie, Paris (France))

    1993-04-02

    Assessment of the long-term cardiac effects of mediastinal radiotherapy for Hodgkin's disease, by Thallium scintigraphy. 32 patients (14 males and 18 females) who underwent mantle field radiotherapy for Hodgkin's disease were included in this study. Twenty patients received 4 fractions of 2.5 Gy per week and 12, five fraction of 2 Gy per week, delivered on alternate days. All the patients, except three, performed exercise testing electrocardiogram and Thallium-201 tomoscintigraphy. The average time interval from completion of treatment to the study was 7 years (range 3--13 years). No patients had clinical symptoms of cardiac disease. Mean age at the time of the study was 35 years (range 23--48 years). Two electrocardiograms revealed left bundle branch block and the patients were excluded from the study. Only one out of 27 exercise electrocardiograms was abnormal in a patient with mitral valve prolapse, who was also excluded from the study. Twenty-six scintigraphies were evaluable. Twenty-two (85%) were clearly abnormal with partial or complete redistribution on delayed images. The anterior region was affected in 19 of these cases (86%). Four explorations were undoubtedly normal. Coronary angiography was not performed for ethical reasons in these asymptomatic patients. Despite possible false positive tests, the high rate of abnormality (85%) in this small series is striking. These preliminary data justify larger studies and a close long-term follow-up of these patients. 24 refs., 1 fig., 2 tabs.

  2. Thallium occurrence and partitioning in soils and sediments affected by mining activities in Madrid province (Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Gonzalez, M.A.; Garcia-Guinea, J. [National Museum of Natural Sciences, CSIC, Jose Gutierrez Abascal 2, 28006 Madrid (Spain); Laborda, F. [Group of Analytical Spectroscopy and Sensors Group, Institute of Environmental Sciences, University of Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza (Spain); Garrido, F., E-mail: fernando.garrido@mncn.csic.es [National Museum of Natural Sciences, CSIC, Jose Gutierrez Abascal 2, 28006 Madrid (Spain)

    2015-12-01

    Thallium (Tl) and its compounds are toxic to biota even at low concentrations but little is known about Tl concentration and speciation in soils. An understanding of the source, mobility, and dispersion of Tl is necessary to evaluate the environmental impact of Tl pollution cases. In this paper, we examine the Tl source and dispersion in two areas affected by abandoned mine facilities whose residues remain dumped on-site affecting to soils and sediments of natural water courses near Madrid city (Spain). Total Tl contents and partitioning in soil solid phases as determined by means of a sequential extraction procedure were also examined in soils along the riverbeds of an ephemeral and a permanent streams collecting water runoff and drainage from the mines wastes. Lastly, electronic microscopy and cathodoluminescence probe are used as a suitable technique for Tl elemental detection on thallium-bearing phases. Tl was found mainly bound to quartz and alumino-phyllosilicates in both rocks and examined soils. Besides, Tl was also frequently found associated to organic particles and diatom frustules in all samples from both mine scenarios. These biogenic silicates may regulate the transfer of Tl into the soil-water system. - Highlights: • Abandoned mine residues are Tl sources in soils of Madrid catchment area. • Tl was associated to quartz and aluminosilicates in both rocks and soils. • Tl was frequently found associated to organic particles and diatom frustules. • Cathodoluminescence is a suitable technique for Tl detection on soils and rocks.

  3. [Detecting Thallium in Water Samples using Dispersive Liquid Phase Microextraction-Graphite Furnace Atomic Absorption Spectroscopy].

    Science.gov (United States)

    Zhu, Jing; Li, Yan; Zheng, Bo; Tang, Wei; Chen, Xiao; Zou, Xiao-li

    2015-11-01

    To develope a method of solvent demulsification dispersive liquid phase microextraction (SD-DLPME) based on ion association reaction coupled with graphite furnace atomic absorption spectroscopy (GFAAS) for detecting thallium in water samples. Methods Thallium ion in water samples was oxidized to Tl(III) with bromine water, which reacted with Cl- to form TlCl4-. The ionic associated compound with trioctylamine was obtained and extracted. DLPME was completed with ethanol as dispersive solvent. The separation of aqueous and organic phase was achieved by injecting into demulsification solvent without centrifugation. The extractant was collected and injected into GFAAS for analysis. With palladium colloid as matrix modifier, a two step drying and ashing temperature programming process was applied for high precision and sensitivity. The linear range was 0.05-2.0 microg/L, with a detection limit of 0.011 microg/L. The relative standard derivation (RSD) for detecting Tl in spiked water sample was 9.9%. The spiked recoveries of water samples ranged from 94.0% to 103.0%. The method is simple, sensitive and suitable for batch analysis of Tl in water samples.

  4. The learning machine in quantitative chemical analysis : Part I. Anodic Stripping Voltammetry of Cadmium, Lead and Thallium

    NARCIS (Netherlands)

    Bos, M.; Jasink, G.

    1978-01-01

    The linear learning machine method was applied to the determination of cadmium, lead and thallium down to 10-8 M by anodic stripping voltammetry at a hanging mercury drop electrode. With a total of three trained multicategory classifiers, concentrations of Cd, Pb and Tl could be predicted with an

  5. Thallium chloride 201Tl combined with single photon emission computed tomography (SPECT) in the evaluation of vestibular schwannoma growth

    DEFF Research Database (Denmark)

    Charabi, Samih Ahmed; Lassen, N A; Thomsen, J

    1997-01-01

    Thallium chloride 201Tl combined with SPECT was performed in a series of 29 patients with neuroradiological evidence of vestibular schwannoma (VS). The relative tumor uptake (U) and relative tumor concentration (C) of the radiotracer 201Tl was determined, and the cerebellum served as a reference...

  6. DISSOLUTION OF LANTHANUM FLUORIDE PRECIPITATES

    Science.gov (United States)

    Fries, B.A.

    1959-11-10

    A plutonium separatory ore concentration procedure involving the use of a fluoride type of carrier is presented. An improvement is given in the derivation step in the process for plutonium recovery by carrier precipitation of plutonium values from solution with a lanthanum fluoride carrier precipitate and subsequent derivation from the resulting plutonium bearing carrier precipitate of an aqueous acidic plutonium-containing solution. The carrier precipitate is contacted with a concentrated aqueous solution of potassium carbonate to effect dissolution therein of at least a part of the precipitate, including the plutonium values. Any remaining precipitate is separated from the resulting solution and dissolves in an aqueous solution containing at least 20% by weight of potassium carbonate. The reacting solutions are combined, and an alkali metal hydroxide added to a concentration of at least 2N to precipitate lanthanum hydroxide concomitantly carrying plutonium values.

  7. Computer simulation of superionic fluorides

    CERN Document Server

    Castiglione, M

    2000-01-01

    experimentally gives an indication of the correlations between nearby defects is well-reproduced. The most stringent test of simulation model transferability is presented in the studies of lead tin fluoride, in which significant 'covalent' effects are apparent. Other similarly-structured compounds are also investigated, and the reasons behind the adoption of such an unusual layered structure, and the mobility and site occupation of the anions is quantified. In this thesis the nature of ion mobility in cryolite and lead fluoride based compounds is investigated by computer simulation. The phase transition of cryolite is characterised in terms of rotation of AIF sub 6 octahedra, and the conductive properties are shown to result from diffusion of the sodium ions. The two processes appear to be unrelated. Very good agreement with NMR experimental results is found. The Pb sup 2 sup + ion has a very high polarisability, yet treatment of this property in previous simulations has been problematic. In this thesis a mor...

  8. Groundwater fluoride contamination: A reappraisal

    Directory of Open Access Journals (Sweden)

    Amlan Banerjee

    2015-03-01

    Full Text Available Dissolution of fluorite (CaF2 and/or fluorapatite (FAP [Ca5(PO43F], pulled by calcite precipitation, is thought to be the dominant mechanism responsible for groundwater fluoride (F− contamination. Here, one dimensional reactive–transport models are developed to test this mechanism using the published dissolution and precipitation rate kinetics for the mineral pair FAP and calcite. Simulation results correctly show positive correlation between the aqueous concentrations of F− and CO32− and negative correlation between F− and Ca2+. Results also show that precipitation of calcite, contrary to the present understanding, slows down the FAP dissolution by 106 orders of magnitude compared to the FAP dissolution by hydrolysis. For appreciable amount of fluoride contamination rock–water interaction time must be long and of order 106 years.

  9. Estuarine response of fluoride - Investigations in Azhikode Estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Balachandran, K.K.; Joseph, T.; Sankaranarayanan, V.N.

    Concentrations of fluoride in Azhikode estuarine region (Kerala, India) were measured as a function of chlorinity during the different seasons. The type of behaviour indicated that fluoride was regulated by sea water incursion alone. Fluoride...

  10. PRECIPITATION OF URANIUM PEROXIDE OF LOW FLUORIDE CONTENT FROM SOLUTIONS CONTAINING FLUORIDES

    Science.gov (United States)

    King, E.J.; Clark, H.M.

    1958-08-12

    S>A method is described for the preparation of fluoride free uraniunn peroxide precipitates, even though the solution from which the precipitation is made is contaminated with fluorides. This is accomplished by add ing aluminum ions to the solution, where they complex any fluoride present and prevent its precipitation with the uramum peroxide.

  11. Topical use of fluorides for caries control.

    Science.gov (United States)

    Pessan, Juliano Pelim; Toumba, Kyriacos Jack; Buzalaf, Marília Afonso Rabelo

    2011-01-01

    Since the early findings on the protective effects of fluoride present in drinking water upon caries incidence and prevalence, intensive research has been conducted in order to determine the benefits, safety, as well as the cost-effectiveness of other modalities of fluoride delivery. The present chapter reviews the various forms of topical fluoride use - professionally and self-applied - with special emphasis on clinical efficacy and possible side effects. The most widely used forms of fluoride delivery have been subject of several systematic reviews, providing strong evidence supporting the use of dentifrices, gels, varnishes and mouth rinses for the control of caries progression. Dentifrices with fluoride concentrations of 1,000 ppm and above have been shown to be clinically effective in caries prevention when compared to a placebo treatment, but the evidence regarding formulations with 450-550 ppm is still subject of debate. Therefore, the recommendation for low-fluoride dentifrice use must take into account both risks and benefits. The evidence for the combined use of two modalities of fluoride application in comparison to a single modality is still inconsistent, implying that more studies with adequate methodology are needed to determine the real benefits of each method. Considering the currently available evidence and risk-benefit aspects, it seems justifiable to recommend the use of fluoridated dentifrices to individuals of all ages, and additional fluoride therapy should also be targeted towards individuals at high caries risk. Copyright © 2011 S. Karger AG, Basel.

  12. Fluoride removal by adsorption on thermally treated lateritic soils

    OpenAIRE

    Kefyalew Gomoro; Feleke Zewge; Bernd Hundhammer; Negussie Megersa

    2012-01-01

    The ability of lateritic soils to remove fluoride from water has been studied. Important issues considered in the study include the relation between the mineral composition of soils and their ability to remove fluoride, the effect of thermal treatment of the soil on fluoride removal; the predominant fluoride containing species remain in the treated water and the possible mechanism of fluoride removal by lateritic soils. The fluoride removal capacity of thermally treated lateritic soils used i...

  13. 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.

  14. Fluorescent Sensing of Fluoride in Cellular System

    Science.gov (United States)

    Jiao, Yang; Zhu, Baocun; Chen, Jihua; Duan, Xiaohong

    2015-01-01

    Fluoride ions have the important roles in a lot of physiological activities related with biological and medical system, such as water fluoridation, caries treatment, and bone disease treatment. Great efforts have been made to develop new methods and strategies for F- detection in the past decades. Traditional methods for the detection of F- including ion chromatography, ion-selective electrodes, and spectroscopic techniques have the limitations in the biomedicine research. The fluorescent probes for F- are very promising that overcome some drawbacks of traditional fluoride detection methods. These probes exhibit high selectivity, high sensitivity as well as quick response to the detection of fluoride anions. The review commences with a brief description of photophysical mechanisms for fluorescent probes for fluoride, including photo induced electron transfer (PET), intramolecular charge transfer (ICT), fluorescence resonance energy transfer (FRET), and excited-state intramolecular proton transfer (ESIPT). Followed by a discussion about common dyes for fluorescent fluoride probes, such as anthracene, naphalimide, pyrene, BODIPY, fluorescein, rhodamine, resorufin, coumarin, cyanine, and near-infrared (NIR) dyes. We divide the fluorescent probes for fluoride in cellular application systems into nine groups, for example, type of hydrogen bonds, type of cleavage of Si-O bonds, type of Si-O bond cleavage and cylization reactions, etc. We also review the recent reported carriers in the delivery of fluorescent fluoride probes. Seventy-four typical fluorescent fluoride probes are listed and compared in detail, including quantum yield, reaction medium, excitation and emission wavelengths, linear detection range, selectivity for F-, mechanism, and analytical applications. Finally, we discuss the future challenges of the application of fluorescent fluoride probes in cellular system and in vivo. We wish that more and more excellent fluorescent fluoride probes will be developed

  15. Bis(2-mercapto-1-R-imidazolyl)hydroborato complexes of aluminium, gallium, indium and thallium: compounds possessing gallium-gallium bonds and a trivalent thallium alkyl.

    Science.gov (United States)

    Yurkerwich, Kevin; Coleman, Fergal; Parkin, Gerard

    2010-08-14

    The reactions of bis(mercaptoimidazolyl)hydroborato derivatives [Bm(R)]M' (R = Me, Bu(t); M' = Li, Na, Tl) with MX(3) trihalides of aluminium, gallium and indium yield both 1:1 and 2:1 complexes of the types [Bm(R)]MX(2) and [Bm(R)](2)MX, respectively. Structurally characterized examples of the [Bm(R)]MX(2) series include [Bm(Me)]AlCl(2), [Bm(Me)]GaI(2), [Bm(Me)]InI(2), [Bm(Bu(t))]AlCl(2) and [Bm(Bu(t))]GaX(2) (X = Cl, Br, I), while structurally characterized examples of the [Bm(R)](2)MX series include [Bm(Bu(t))](2)InX (X = Cl, Br, I). In addition to the halide complexes, the trivalent dimethyl thallium complex [Bm(Bu(t))]TlMe(2) has been synthesized via the reaction of [Bm(Bu(t))]Tl with Me(2)TlCl. The reactions of [Bm(R)]M' with the monovalent halides, "GaI", InCl and InI, result in disproportionation. In the case of indium, the mononuclear complexes [Bm(Bu(t))](2)InI and [Bm(Bu(t))]InCl(kappa(2)-mim(Bu(t))) are obtained, whereas for gallium, dinuclear compounds that feature Ga-Ga bonds, namely [Bm(R)](GaI)(GaI)[Bm(R)] (R = Me, Bu(t)) have been isolated.

  16. 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......: recent water fluoridation schemes in California, USA; salt fluoridation in Jamaica; milk fluoridation in Chile; and the development of "affordable" fluoride toothpastes in Indonesia. Common themes are the concern to reduce demands for compliance with fluoride regimes that rely upon action by individuals...... and their families, and the issue of cost. We recommend that a community should use no more than one systemic fluoride (i.e. water or salt or milk fluoridation) combined with the use of fluoride toothpastes, and that the prevalence of dental fluorosis should be monitored in order to detect increases in or higher...

  17. Thallium stress testing does not predict cardiovascular risk in diabetic patients with end-stage renal disease undergoing cadaveric renal transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Holley, J.L.; Fenton, R.A.; Arthur, R.S. (Univ. of Pittsburgh, PA (USA))

    1991-05-01

    This study assessed the usefulness of thallium stress testing as a predictor of perioperative cardiovascular risk in diabetic patients with end-stage renal disease undergoing cadaveric renal transplantation. Demographic factors influencing the exercise performance in these patients were also examined. The medical records of 189 consecutive patients with diabetic nephropathy who were evaluated for cadaveric renal transplantation were reviewed. Thallium stress testing was the initial examination of cardiovascular status in 141 patients. An adequate examination was one in which at least 70% of maximum heart rate was achieved. A thallium stress test was normal if there were no ST segment depressions on the electrocardiogram and no perfusion abnormalities on the thallium scan. Forty-four patients underwent cardiac catheterization as the initial evaluation (Group C) and four patients underwent transplantation without a formal cardiovascular evaluation (Group D). Sixty-four of the 141 patients undergoing thallium stress testing had an adequate and normal examination (Group A). The incidence of perioperative cardiac events in this group was 2%. Seventy-seven patients (Group B) had an abnormal (n = 41) or an inadequate (n = 36) thallium stress test and most (n = 61) then underwent coronary angiography. The use of beta-blockers was the only predictor of an abnormal or inadequate thallium stress test. Forty-three percent of patients with inadequate or abnormal thallium stress tests had significant coronary artery disease on cardiac catheterization. The perioperative risk of cardiac events was not different in Group A versus Groups B, C, and D combined. Survival of Group A and B patients was not different but was significantly longer than that of Group C patients.

  18. Multiple inorganic toxic substances contaminating the groundwater of Myingyan Township, Myanmar: arsenic, manganese, fluoride, iron, and uranium.

    Science.gov (United States)

    Bacquart, Thomas; Frisbie, Seth; Mitchell, Erika; Grigg, Laurie; Cole, Christopher; Small, Colleen; Sarkar, Bibudhendra

    2015-06-01

    In South Asia, the technological and societal shift from drinking surface water to groundwater has resulted in a great reduction of acute diseases due to water borne pathogens. However, arsenic and other naturally occurring inorganic toxic substances present in groundwater in the region have been linked to a variety of chronic diseases, including cancers, heart disease, and neurological problems. Due to the highly specific symptoms of chronic arsenic poisoning, arsenic was the first inorganic toxic substance to be noticed at unsafe levels in the groundwater of West Bengal, India and Bangladesh. Subsequently, other inorganic toxic substances, including manganese, uranium, and fluoride have been found at unsafe levels in groundwater in South Asia. While numerous drinking water wells throughout Myanmar have been tested for arsenic, relatively little is known about the concentrations of other inorganic toxic substances in Myanmar groundwater. In this study, we analyzed samples from 18 drinking water wells (12 in Myingyan City and 6 in nearby Tha Pyay Thar Village) and 2 locations in the Ayeyarwaddy River for arsenic, boron, barium, beryllium, cadmium, cobalt, chromium, copper, fluoride, iron, mercury, manganese, molybdenum, nickel, lead, antimony, selenium, thallium, uranium, vanadium, and zinc. Concentrations of arsenic, manganese, fluoride, iron, or uranium exceeded health-based reference values in most wells. In addition, any given well usually contained more than one toxic substance at unsafe concentrations. While water testing and well sharing could reduce health risks, none of the wells sampled provide water that is entirely safe with respect to inorganic toxic substances. It is imperative that users of these wells, and users of other wells that have not been tested for multiple inorganic toxic substances throughout the region, be informed of the need for drinking water testing and the health consequences of drinking water contaminated with inorganic toxic

  19. STUDY OF FLUORIDE GLASSES DEVITRIFICATION-BASED ...

    African Journals Online (AJOL)

    4 mars 2013 ... ABSTRACT. The kinetics of devitrification of fluoride glasses stabilized by magnesium fluoride when heated for some time between the glass transition and melting temperatures. The crystallization kinetics of AlF3-YF3-PbF2-CdF2-MgF2 glass prepared by melting the halide powders were studied by.

  20. 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.

  1. HOUSEHOLD PURIFICATION OF FLUORIDE CONTAMINATED MAGADI (TRONA)

    DEFF Research Database (Denmark)

    Nielsen, Joan Maj; Dahi, Elian

    1997-01-01

    Purification of fluoride contaminated magadi is studied using bone char sorption and calcium precipitation. The bone char treatment is found to be workable both in columns and in batches where the magadi is dissolved in water prior to treatment. The concentrations in the solutions were 89 g magadi...... treatment method. A procedure for purification of fluoride contaminated magadi at household level is described....

  2. Hydrogeochemical framework and factor analysis of fluoride ...

    African Journals Online (AJOL)

    Fluoride contamination of groundwater within the Savelugu-Nanton District was assessed using hydrogeochemical framework and multivariate statistical approach. Eighty-one (No) boreholes were sampled for quality assessment in May and June 2008. The main objective of this study was to assess the fluoride levels in ...

  3. Solvothermal chemistry of luminescent lanthanide fluorides

    OpenAIRE

    Jayasundera, Anil

    2009-01-01

    Exploration of novel lanthanide fluoride framework materials in inorganic-organic hybrid systems under solvothermal conditions towards development of new luminescent materials is discussed. X-ray single crystal and powder diffraction methods have been used as crystallographic characterisation techniques. Determination and study of luminescence properties for selected hybrid materials has also been carried out. The first organically templated luminescent lanthanide fluoride fram...

  4. Evaluation of thallium-201 scanning for detection of latent coronary artery disease

    Science.gov (United States)

    Johnson, P. C.; Leblanc, A.; Deboer, L.; Jhingran, S.

    1978-01-01

    The use of thallium imaging as a noninvasive method to accurately screen shuttle passengers for latent coronary artery disease was investigated. All radionuclide procedures were performed using an Anger type camera with a high resolution collimator. A minimum of 200,000 counts were collected for each image using a 20% window centered on the 69-83 keV X-rays. For the images obtained following injection with the patient at rest, the testing was begun 10 minutes after injection. Injections of TT during exercise were made at a point near the termination of the treadmill procedure as determined by either the appearance of ST segment changes on the electrocardiogram consistant with subendocardial ischemia, the appearance of angina-like chest pain in the patient or fatigue in the patient which required cessation of the test. The severity of heart disease was based on the medical history, physical exam, exercise electrocardiograms, chest X-rays and the coronary arteriogram.

  5. Thallium Analysis in Environmental Samples by Inductively Coupled Plasma Mass Spectrometry; Analisis de Talio en Muestras Ambientales por Espectrometria de Masas con Fuente de Plasma de Acoplamiento Inductivo

    Energy Technology Data Exchange (ETDEWEB)

    Higueras, I.; Fernandez, M.; Conde, E.; Gajate, A.

    2008-08-06

    Due to its high toxicity, thallium has been considered by the US Environmental Protection Agency as one of the priority pollutants to be controlled. While being a highly toxic element, thallium has been studied to a much lesser degree than other toxic elements, mainly because thallium is often undetected by classical analytical methods. Thallium is a rare and dispersed element that occurs mainly in sulfur-containing ores. Thus, it is a potential pollutant to surrounding environment, if Tl-rich mineral and/or their industrial wastes are not properly disposed. In this work an Inductively Coupled Plasma Mass Spectrometry analytical procedure has been developed in order to determine thallium in environmental solid samples and its application to the study of this element as a potential pollutant associated with natural and anthropogenic activities. The analytical procedure has been validated by the use of appropriate reference materials, and through the isotope dilution technique as a primary method of measurement. Finally, the developed procedure has been applied to several samples from a mining area, as one of the scenarios where thallium it is likely to occur. (Author) 87 refs.

  6. Diethylenetriaminium hexafluoridotitanate(IV fluoride

    Directory of Open Access Journals (Sweden)

    J. Lhoste

    2008-11-01

    Full Text Available The title compound, (C6H21N4[TiF6]F, was synthesized by the reaction of TiO2, tris(2-aminoethylamine, HF and ethanol at 463 K in a microwave oven. The crystal structure consists of two crystallographically independent [TiF6]2− anions, two fluoride anions and two triply-protonated tris(2-aminoethylamine cations. The Ti atoms are coordinated by six F atoms within slightly distorted octahedra. The anions and cations are connected by intermolecular N—H...F hydrogen bonds.

  7. A Case-Control Study of Prenatal Thallium Exposure and Low Birth Weight in China.

    Science.gov (United States)

    Xia, Wei; Du, Xiaofu; Zheng, Tongzhang; Zhang, Bin; Li, Yuanyuan; Bassig, Bryan A; Zhou, Aifen; Wang, Youjie; Xiong, Chao; Li, Zhengkuan; Yao, Yuanxiang; Hu, Jie; Zhou, Yanqiu; Liu, Juan; Xue, Weiyan; Ma, Yue; Pan, Xinyun; Peng, Yang; Xu, Shunqing

    2016-01-01

    Thallium (Tl) is a highly toxic heavy metal widely present in the environment. Case reports have suggested that maternal exposure to high levels of Tl during pregnancy is associated with low birth weight (LBW), but epidemiological data are limited. This study was designed to evaluate whether prenatal Tl exposure is associated with an increased risk of LBW. This case-control study involving 816 study participants (204 LBW cases and 612 matched controls) was conducted in Hubei Province, China, in 2012-2014. Tl concentrations were measured in maternal urine collected at delivery, and associations with LBW were evaluated using conditional logistic regression. Higher maternal urinary Tl levels were significantly associated with increased risk of LBW [crude odds ratio (OR) = 1.52; 95% CI: 1.00, 2.30 for the highest vs. lowest tertile], and the association was similarly elevated after adjustment for potential confounders (adjusted OR = 1.90; 95% CI: 1.01, 3.58 for the highest vs. lowest tertile). Stratified analyses showed slightly higher risk estimates for LBW associated with higher Tl levels for mothers case-control study to investigate the association between prenatal Tl exposure and LBW. The results suggest that prenatal exposure to high levels of Tl may be associated with an increased risk of LBW. Xia W, Du X, Zheng T, Zhang B, Li Y, Bassig BA, Zhou A, Wang Y, Xiong C, Li Z, Yao Y, Hu J, Zhou Y, Liu J, Xue W, Ma Y, Pan X, Peng Y, Xu S. 2016. A case-control study of prenatal thallium exposure and low birth weight in China. Environ Health Perspect 124:164-169; http://dx.doi.org/10.1289/ehp.1409202.

  8. Evaluation of myocardial abnormalities in patients with collagen diseases by thallium-201 myocardial scintigram

    Energy Technology Data Exchange (ETDEWEB)

    Yamano, Shigeru (Nara Medical Univ., Kashihara (Japan))

    1992-08-01

    This study was performed to evaluate myocardial lesions in patients with collagen diseases by rest and exercise thallium-201 myocardial scintigraphies. A total of 76 patients without ischemic ECG changes, consisting of 27 cases of systemic lupus erythematosus (SLE), 17 cases of polymyositis or dermatomyositis (PM[center dot]DM), 11 cases of progressive systemic sclerosis (PSS), and 21 cases of Sjoegren's syndrome (SjS), were enrolled in this study. Reversible exercise-induced defects suggesting myocardial ischemia were noted in 12 cases of SLE, 5 cases of PM[center dot]DM, 3 cases of PSS, and 3 cases of SjS. Of the 23 patients who had exercise-induced defects, 9 patients showed normal coronary angiograms by cardiac catheterization. Fixed hypoperfusion areas were observed in 5 cases of SLE, 6 cases of PM[center dot]DM, 4 cases of PSS and 3 cases of SjS. Rest thallium-201 myocardial scintigraphy disclosed hypoperfusion areas, which were not induced by exercise, in 1 case of SLE, 4 cases of PM[center dot]DM, 1 case of PSS and 5 cases of SjS. Endomyocardial biopsy was performed on 20 patients. Myocardial lesions in PM[center dot]DM and PSS were more severe and wide spread than in SLE. Ejection fraction and fractional shortening evaluated by echocardiography had no significant differences between each disease group and the healthy control group. These findings suggest that patients with collagen diseases show the presence of abnormalities of coronary circulation at the level of the intramyocardial vasculature in the stage before impairment of cardiac function, myocardial fibrosis and functional abnormalities of the cell membrane level that were not dependent on myocardial ischemia. (author).

  9. Development and Applications of Thallium isotopes: a new proxy tracking the extent of manganese oxide burial

    Science.gov (United States)

    Owens, J. D.; Nielsen, S.; Ostrander, C.; Peterson, L. C.; Anbar, A. D.

    2015-12-01

    Thallium (Tl) isotopes are a new and potential powerful paleoredox proxy with the possibility to track bottom water oxygen conditions based on the burial flux of manganese oxides. Thallium has a residence time of ~20 thousand years, which is long enough to render modern oxic seawater conservative with respect to concentration and isotopes. The isotopic signature of Tl in the global ocean is driven mainly by two outputs (1) adsorption onto manganese oxides and (2) low temperature oceanic crust alteration. Importantly, the isotopic inputs of Tl are all nearly the same value; thus, the isotopic composition and flux of the outputs almost exclusively set the seawater signature. For relatively short term redox events it is reasonable to assume that the dominant isotope fractionation process is associated with manganese oxide precipitation because low temperature alteration is controlled by long-term average ocean crust production rates. We present a broad range of modern samples that span several open ocean profiles combined with water column and sediment profiles from the permanently anoxic basins of the Black Sea and Cariaco Basins. The open ocean shows no variation in depth profiles that encompass most of the major water masses in the Atlantic and Southern Oceans. The anoxic basins, however, reveal Tl isotope signatures closer to their inputs, which is likely due to basinal restriction. The authigenic fraction of organic-rich sediments from the Black Sea and Cariaco Basin capture the Tl isotope value of the overlying water column, which shows that Tl isotopes could be applied as a faithful deep time redox proxy. For the first time, we will present new data showing that Tl isotopes is tracking bottom water ocean oxygenation. We are applying this isotope system to ancient samples, testing the spatial and temporal variability of ocean oxygenation coinciding with major biogeochemical events.

  10. Ion release from, and fluoride recharge of a composite with a fluoride-containing bioactive glass.

    Science.gov (United States)

    Davis, Harry B; Gwinner, Fernanda; Mitchell, John C; Ferracane, Jack L

    2014-10-01

    Materials that are capable of releasing ions such as calcium and fluoride, that are necessary for remineralization of dentin and enamel, have been the topic of intensive research for many years. The source of calcium has most often been some form of calcium phosphate, and that for fluoride has been one of several metal fluoride or hexafluorophosphate salts. Fluoride-containing bioactive glass (BAG) prepared by the sol-gel method acts as a single source of both calcium and fluoride ions in aqueous solutions. The objective of this investigation was to determine if BAG, when added to a composite formulation, can be used as a single source for calcium and fluoride ion release over an extended time period, and to determine if the BAG-containing composite can be recharged upon exposure to a solution of 5000ppm fluoride. BAG 61 (61% Si; 31% Ca; 4% P; 3% F; 1% B) and BAG 81 (81% Si; 11% Ca; 4% P; 3% F; 1% B) were synthesized by the sol-gel method. The composite used was composed of 50/50 Bis-GMA/TEGDMA, 0.8% EDMAB, 0.4% CQ, and 0.05% BHT, combined with a mixture of BAG (15%) and strontium glass (85%) to a total filler load of 72% by weight. Disks were prepared, allowed to age for 24h, abraded, then placed into DI water. Calcium and fluoride release was measured by atomic absorption spectroscopy and fluoride ion selective electrode methods, respectively, after 2, 22, and 222h. The composite samples were then soaked for 5min in an aqueous 5000ppm fluoride solution, after which calcium and fluoride release was again measured at 2, 22, and 222h time points. Prior to fluoride recharge, release of fluoride ions was similar for the BAG 61 and BAG 81 composites after 2h, and also similar after 22h. At the four subsequent time points, one prior to, and three following fluoride recharge, the BAG 81 composite released significantly more fluoride ions (p0.05) for the two composites. These results show that, when added to a composite formulation, fluoride-containing bioactive glass

  11. Effects of periodic fluoride treatment on fluoride ion release from fresh orthodontic adhesives.

    Science.gov (United States)

    Lim, Bum-Soon; Lee, Shin-Jae; Lim, Young-Jun; Ahn, Sug-Joon

    2011-11-01

    Periodic fluoride treatment may contribute to the ability of fresh orthodontic adhesives to provide long-term F(-) release. The effects of periodic fluoride treatment on the amount of F(-) release from fresh orthodontic adhesives was investigated. F(-) release was measured from a nonfluoride-releasing composite, a fluoride-releasing composite, a polyacid-modified composite (compomer), and two resin-modified glass-ionomer cements (RMGICs) at 1, 2, and 5 days after one of the following treatments: 225 ppm F(-) solution, 900 ppm F(-) solution, acidulated phosphate fluoride gel (APF), fluoridated dentifrice, and deionised water (control). F(-) release was measured in a 5-day cycle, which was repeated 9 consecutive times. The amount of F(-) release for each group was analysed using the repeated measures analysis of variance. Statistical significance was set at a level of α=0.05. Periodic fluoride treatment temporarily increased F(-) release in fresh fluoride-releasing orthodontic adhesives, but not in fresh nonfluoride-releasing composite. The order of effective fluoride-release was RMGICs>compomer>fluoride-releasing composite>nonfluoride-releasing composite. The application of APF or 900 ppm F(-) solution was the most effective way to maintain F(-) release from fresh orthodontic adhesives. However, the amount of F(-) release gradually decreased with increasing specimen age. Given the difficulty of routine use of APF at home, the results of this study show that a combination of RMGICs and high-dose fluoride mouth rinse is the most effective protocol to maintain F(-) release from fresh orthodontic adhesives. Most studies have investigated fluoride-uptake abilities using aged materials in which fluoride had been lost for at least 1 month. This study has found that periodic fluoride treatment altered the conventional F(-) release pattern of fresh fluoride-releasing materials and type of fluoride-containing medium plays a more critical role in fluoride recharging of the

  12. Thallium myocardial tomoscintigraphy: detection of ischemia during weaning from mechanical ventilation in patients with chronic obstructive pulmonary disease. Tomoscintigraphie myocardique au thallium: detection de l'ischemie provoquee par le sevrage de la ventilation assistee chez le bronchiteux chronique

    Energy Technology Data Exchange (ETDEWEB)

    Andre, L.; Valette, H.; Obama, S.; Archambaud, F.; Richard, C.; Teboul, J.L.; Hebert, J.L.; Auzepy, P.; Desgrez, A. (Hopital de Bicetre, 94 - Le Kremlin-Bicetre (FR))

    1990-01-01

    In order to evidence myocardial ischemia-leading to ventricular dysfunction-during weaning from mechanical ventilation in patients with chronic obstructive pulmonary disease, thallium myocardial tomography and gated blood pool studies were performed in 9 patients during mechanical ventilation and during weaning from mechanical ventilation. During the latter, results of gated blood pool studies showed a diffuse homogeneous left ventricular dysfunction. A fixed lower thallium uptake in the septum than in the lateral wall was found with the quantitative analysis of myocardial tomograms. Partial volume effect is likely the cause of this septal defect. The hypothesis of a diffuse ischemia cannot be excluded; but, without the absolute quantification of tomographic data, it cannot be proven.

  13. Fluoride in saliva and dental biofilm after 1500 and 5000 ppm fluoride exposure.

    Science.gov (United States)

    Staun Larsen, Line; Baelum, Vibeke; Tenuta, Livia Maria Andaló; Richards, Alan; Nyvad, Bente

    2017-09-01

    The aim of this randomized, double-blind, crossover study was to measure fluoride in saliva and 7-day-old biofilm fluid and biofilm solids after rinsing three times per day for 3 weeks with 0, 1500, or 5000 ppm fluoride (NaF). Following the 3-week wash-in/wash-out period, including 1 week of biofilm accumulation, saliva and biofilm samples were collected from 12 participants immediately before (background fluoride), and 10, 30, and 60 min after a single rinse. Biofilm samples were separated into fluid and solids, and samples were analyzed using a fluoride electrode (microanalysis). The background fluoride concentration was statistically significantly higher in the 5000 compared to the 1500 ppm F rinse group in all three compartments (22.3 and 8.1 μM in saliva, 126.8 and 58.5 μM in biofilm fluid, and 10,940 and 4837 μmol/kg in biofilm solids). The 1-h fluoride accumulation for the 5000 ppm F rinse was higher than for the 1500 ppm F rinse in all three compartments, although not statistically significant for saliva and biofilm solids. Regular exposure to 5000 ppm fluoride elevates background fluoride concentrations in saliva, biofilm fluid, and biofilm solids compared to 1500 ppm fluoride. Increasing the fluoride concentration almost 3.5 times (from 1500 to 5000 ppm) only elevates the background fluoride concentrations in saliva, biofilm fluid, and biofilm solids twofold. Even though fluoride toothpaste may be diluted by saliva, the results of the present study indicate that use of 5000 ppm fluoride toothpaste might lead to improved caries control.

  14. 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 ...

  15. Studies on the comparative effect of sodium fluoride on collagen ...

    African Journals Online (AJOL)

    use

    2011-12-12

    Dec 12, 2011 ... protein concentration in lungs (Stawiarska-Pieta et al.,. 2009). Fluoride exerts diverse cellular effects in a time-, concentration-, and cell-type-dependent manner. The main toxic effect of fluoride in cells consists of its interact- tion with enzymes. In most cases, fluoride acts as an enzyme inhibitor, but, fluoride ...

  16. Fluoridation and Defluoridation. Training Module 2.230.2.77.

    Science.gov (United States)

    McMullen, L. D.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with fluoridation and fluoride feeding equipment. Enclosed are objectives, an instructor guide, student handouts and transparency masters. The module considers the principles and purposes of fluoridation, methods of feeding fluoride,…

  17. Fluoride removal by adsorption on thermally treated lateritic soils ...

    African Journals Online (AJOL)

    The ability of lateritic soils to remove fluoride from water has been studied. Important issues considered in the study include the relation between the mineral composition of soils and their ability to remove fluoride, the effect of thermal treatment of the soil on fluoride removal; the predominant fluoride containing species ...

  18. 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.

  19. Studies of photon spectra from a thallium-204 foil source as an aid to dosimetry and shielding

    CERN Document Server

    Francis, T M

    1976-01-01

    Beta ray foil sources incorporating nuclides such as thallium-204, promethium-147 and strontium-90 plus yttrium-90 ar increasingly used in industrial devices such as thickness gauges. These sources are so constructed that they give rise to complex photon spectra containing low energy Bremsstrahlung and X-rays characteristic of the constructional materials. The energy response of practical monitoring instruments is such that they are likely to underestimate the dose due to such spectra unless they are calibrated using appropriate spectra. This report describes a series of measurements carried out on a commercially available thallium-204 foil source and five commonly used shielding materials. The measurements made with a NaI(T1) spectrometer have been corrected for instrumental distortions to obtain the photon spectra in air. These spectra are presented and have been used to compute dose in air with the help of published data on mass energy-absorption coefficients. Also included in the report are data derived f...

  20. Septal myocardial perfusion imaging with thallium-201 in the diagnosis of proximal left anterior descending coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Pichard, A.D.; Wiener, I.; Martinez, E.; Horowitz, S.; Patterson, R.; Meller, J.; Goldsmith, S.J.; Gorlin, R.; Herman, M.V.

    1981-07-01

    The use of myocardial perfusion imaging (MPI) to identify obstructive coronary disease of the left anterior descending coronary artery proximal to the first septal perforator (prox LAD) was studied in 60 patients. Perfusion of the septum and anteroapical areas with thallium-201 injected during exercise was compared to results of coronary arteriography. Septal MPI defect was found in 92.3% of patients with obstruction of the proximal LAD, 27.7% of patients with obstruction of LAD distal to first septal perforator, 0% in patients with obstructions involving right or circumflex arteries, and in 10.5% of patients without coronary disease. Anteroapical MPI defects were found with similar frequency in the three groups with obstructive coronary disease. Septal MPI defect had a sensitivity of 92.3% and specificity of 85.4% in the diagnosis of proximal LAD disease. Normal septal perfusion with thallium-201 virtually excluded proximal LAD disease.

  1. Usefulness of rest-redistribution thallium scan for the indication of PTCA in an interesting case with acute myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Chiba, Hiroshi; Nishimura, Tsunehiko; Mitani, Isao; Matsuo, Takeshi; Uehara, Toshiisa; Hayashida, Kohei; Sumiyoshi, Tetsuya; Haze, Kazuo

    1988-04-01

    A 72-year-old woman with acute myocardial infarction was received coronary thrombolytic therapy. After percutaneous transluminal coronary recanalization (PTCR), the stenosis of LAD became from 99 % to 90 %. Left ventriculogram showed dyskinesis of anterior wall in acute phase. After PTCR, she complained of postinfarctional angina. Thus, in order to evaluate the viability of anterior wall, serial thallium scintigraphy was performed at rest, which showed perfusion defect and redistribution of anterior wall. After percutaneous transluminal coronary angioplasty (PTCA), anterior wall motion became almost normal. The perfusion defect of anterior wall was also gradually disappeared. The serial thallium scintigraphy at rest is an useful method not only to evaluate the viability of myocardium in acute myocardial infarction, but also to follow the effect of PTCA.

  2. 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.

  3. Rearrangement of beta,gamma-unsaturated esters with thallium trinitrate: synthesis of indans bearing a beta-keto ester moiety

    Directory of Open Access Journals (Sweden)

    Silva Jr. Luiz F.

    2006-01-01

    Full Text Available The rearrangement of beta,gamma-unsaturated esters, such as 2-(3,4-dihydronaphthalen-1-yl-propionic acid ethyl ester, with thallium trinitrate (TTN in acetic acid leads to 3-indan-1-yl-2-methyl-3-oxo-propionic acid ethyl ester in good yield, through a ring contraction reaction. The new indans thus obtained feature a beta-keto ester moiety, which would be useful for further functionalization.

  4. Formic acid electrooxidation on thallium-decorated shape-controlled platinum nanoparticles: an improvement in electrocatalytic activity

    OpenAIRE

    Busó-Rogero, Carlos; Perales-Rondón, Juan V.; Farias, Manuel J.S.; Vidal-Iglesias, Francisco J.; Solla-Gullón, José; Herrero, Enrique; Feliu, Juan M.

    2014-01-01

    Thallium modified shape-controlled Pt nanoparticles were prepared and their electrocatalytic activity towards formic acid electrooxidation was evaluated in 0.5 M sulfuric acid. The electrochemical and in situ FTIR spectroscopic results show a remarkable improvement in the electrocatalytic activity, especially in the low potential region (around 0.1–0.2 V vs. RHE). Cubic Pt nanoparticles modified with Tl were found to be more active than the octahedral Pt ones in the entire range of Tl coverag...

  5. Usefulness and limitations of thallium-201 myocardial scintigraphy in delineating location and size of prior myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Niess, G.S.; Logic, J.R.; Russell, R.O. Jr.; Rackley, C.E.; Rogers, W.J.

    1979-05-01

    Thirty-two patients were evaluated at a mean of 7 +- 2 months after infarction with a 12-lead ECG, resting /sup 201/Tl myocardial scintigram, biplane left ventriculogram, and coronary angiograms. From the left ventriculogram, asynergy was quantified as percent abnormally contracting segment (% ACS), the percent of end-diastolic circumference which was either akinetic or dyskinetic. Using a computerized planimetry system, we expressed /sup 201/Tl perfusion defects as a percentage of total potential thallium uptake. Of 21 patients with ECG evidence of prior transmural infarction, a /sup 201/Tl defect was present in 20, and angiographic asynergy was present in all 21. The site of prior infarction by ECG agreed with the /sup 201/T1 defect location in 24 of 32 patients and with site of angiographic asynergy in 23 of 32 patients. Scintigraphic defects were present in only four of 10 patients with ACS less than or equal to 6%, but scintigraphic defects were found in 20 of 22 patients with ACS > 6%. Thallium defect size correlated marginally with angiographic left ventricular ejection fraction but correlated closely with angiographic % ACS. Thallium defect size was similar among patients with one-, two-, or three-vessel coronary artery disease (greater than or equal to 70% stenosis), but thallium defect size was larger in patients with electrocardiographic evidence of transmural infarction or pulmonary capillary wedge pressure > 12 mm Hg. Thus, resting /sup 201/T1 myocardial scintigraphy is useful in localizing and quantifying the extent of prior myocardial infarction, but is insensitive to small infarcts (ACS < 6%).

  6. Influence of Individual Saliva Secretion on Fluoride Bioavailability

    OpenAIRE

    E. A. Naumova; Gaengler, P.; Zimmer, S.; Arnold, W. H.

    2010-01-01

    The aim of this preliminary investigation was to compare the individual saliva secretion rate with the fluoride bioavailability in saliva after using sodium fluoride and amine fluoride. Methods: To assess oral fluoride kinetics 10 highly trained volunteers brushed their teeth with one of the formulations and saliva was collected. The amount of saliva was measured, and the fluoride content was determined. Data underwent statistical analysis using the Mann-Whitney-U test and Pearson correlation...

  7. A study of fluoride groundwater occurrence in Nathenje, Lilongwe, Malawi

    Science.gov (United States)

    Msonda, K. W. M.; Masamba, W. R. L.; Fabiano, E.

    A study was carried out to determine fluoride concentration in groundwaters of Nathenje area situated in Lilongwe District in the central region of Malawi. Water samples were collected from 176 boreholes and shallow wells during different months in 2001 and 2002. Samples were then analysed for fluoride by using a fluoride electrode and an ion selective meter. The results showed that fluoride concentrations for the rainy season varied from dental fluorosis in areas where the fluoride concentration was high.

  8. Enamel silicon and fluoride relationships demonstrating a surface silicon effect that facilitates fluoride uptake.

    Science.gov (United States)

    Levy, J S; Koritzer, R T

    1976-01-01

    This study indicated that a clear relationship exists between silicon and fluoride. We have also demonstrated a probable surface enamel silicon effect that increases fluoride uptake. The complex set of relationships described in the surface chemistry of calcium, tin, and zirconium with fluoride, hydroxide, phosphate, and other surface-occurring ions need not be considered to confuse the specific silicon-fluoride relationship presented here because in this computation we are relating the changes in the silicon and fluoride ion values only. We have, however, considered the thermodynamics of such reactions and intend to elaborate on it in a later publication. We are aware of the small depth of fluoride penetration into enamel after topical treatment Health Foundation, Research Unit at the National Bureau of Standards, Washington, DC 20034, USA.

  9. Determination of thallium at ultra-trace levels in water and biological samples using solid phase spectrophotometry.

    Science.gov (United States)

    Amin, Alaa S; El-Sharjawy, Abdel-Azeem M; Kassem, Mohammed A

    2013-06-01

    A new simple, very sensitive, selective and accurate procedure for the determination of trace amounts of thallium(III) by solid-phase spectrophotometry (SPS) has been developed. The procedure is based on fixation of Tl(III) as quinalizarin ion associate on a styrene-divinylbenzene anion-exchange resin. The absorbance of resin sorbed Tl(III) ion associate is measured directly at 636 and 830 nm. Thallium(I) was determined by difference measurements after oxidation of Tl(I) to Tl(III) with bromine. Calibration is linear over the range 0.5-12.0 μg L(-1) of Tl(III) with relative standard deviation (RSD) of 1.40% (n=10). The detection and quantification limits are 150 and 495 ng L(-1) using 0.6 g of the exchanger. The molar absorptivity and Sandell sensitivity are also calculated and found to be 1.31×10(7) L mol(-1)cm(-1) and 0.00156 ng cm(-2), respectively. The proposed procedure has been successfully applied to determine thallium in water, urine and serum samples. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. The efficient removal of thallium from sintering flue gas desulfurization wastewater in ferrous metallurgy using emulsion liquid membrane.

    Science.gov (United States)

    Yang, Li; Xiao, Jiangping; Shen, Yi; Liu, Xian; Li, Wensong; Wang, Weiyan; Yang, Yunquan

    2017-11-01

    The removal of thallium ions in flue gas desulfurization wastewater from ferrous metallurgic industry was studied by emulsion liquid membrane (ELM) method using 2-ethylhexyl phosphoric acid-2-ethylhexyl ester (P507) as carrier, aviation kerosene (AK) as organic solvent, polyisobutylene succinimide (T154) as surfactant, polyisobutylene (PIB) as additive, and sulfuric acid as internal reagent. Some important influence parameters such as concentrations of carrier, surfactant and stripping agent, agitation speed, extraction time, volume ratios of feed solution to emulsion phase and internal phase to membrane phase, and their effects on the removal efficiency of Tl in the ELM process were investigated and optimized. Under the optimum operating conditions of 2% of carrier, 5% of surfactant, 0.5 M of stripping agent, 350 rpm of agitation speed, 12.5:1 of volume ratio of feed solution to emulsion phase, and 3:1 volume ratio of membrane to internal phase, the maximum extraction efficiency of thallium reached 99.76% within 15-min reaction time. The ICP-MS analysis indicated that the thallium concentration in treated wastewater was below 5 μg/L and could meet the emission standard demand for industrial wastewater enacted by the local government of Hunan province of China. Meanwhile, the extraction of impurity ions calcium and magnesium in the ELM system was investigated. The result showed that an acidic environment would be in favor of the removal of Tl from calcium and magnesium contained in wastewater. Graphical abstract ᅟ.

  11. Thallium isotopes in metallurgical wastes/contaminated soils: A novel tool to trace metal source and behavior.

    Science.gov (United States)

    Vaněk, Aleš; Grösslová, Zuzana; Mihaljevič, Martin; Ettler, Vojtěch; Trubač, Jakub; Chrastný, Vladislav; Penížek, Vít; Teper, Leslaw; Cabala, Jerzy; Voegelin, Andreas; Zádorová, Tereza; Oborná, Vendula; Drábek, Ondřej; Holubík, Ondřej; Houška, Jakub; Pavlů, Lenka; Ash, Christopher

    2018-02-05

    Thallium (Tl) concentration and isotope data have been recorded for contaminated soils and a set of industrial wastes that were produced within different stages of Zn ore mining and metallurgical processing of Zn-rich materials. Despite large differences in Tl levels of the waste materials (1-500mgkg-1), generally small changes in ε205Tl values have been observed. However, isotopically lighter Tl was recorded in fly ash (ε205Tl∼-4.1) than in slag (ε205Tl∼-3.3), implying partial isotope fractionation during material processing. Thallium isotope compositions in the studied soils reflected the Tl contamination (ε205Tl∼-3.8), despite the fact that the major pollution period ended more than 30 years ago. Therefore, we assume that former industrial Tl inputs into soils, if significant, can potentially be traced using the isotope tracing method. We also suggest that the isotope redistributions occurred in some soil (subsurface) horizons, with Tl being isotopically heavier than the pollution source, due to specific sorption and/or precipitation processes, which complicates the discrimination of primary Tl. Thallium isotope analysis proved to be a promising tool to aid our understanding of Tl behavior within the smelting process, as well as its post-depositional dynamics in the environmental systems (soils). Copyright © 2017 Elsevier B.V. All rights reserved.

  12. PROCESS FOR TREATING VOLATILE METAL FLUORIDES

    Science.gov (United States)

    Rudge, A.J.; Lowe, A.J.

    1957-10-01

    This patent relates to the purification of uranium hexafluoride, made by reacting the metal or its tetrafluoride with fluorine, from the frequently contained traces of hydrofluoric acid. According to the present process, UF/sub 6/ containing as an impurity a small amount of hydrofluoric acid, is treated to remove such impurity by contact with an anhydrous alkali metal fluoride such as sodium fluoride. In this way a non-volatile complex containing hydrofluoric acid and the alkali metal fluoride is formed, and the volatile UF /sub 6/ may then be removed by distillation.

  13. Fluoride exposure and reported learning disability diagnosis among Canadian children: Implications for community water fluoridation.

    Science.gov (United States)

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

    2017-09-14

    Recent studies have connected increased fluoride exposure with increased risk of neurodevelopmental-related outcomes, such as ADHD (attention deficit hyperactivity disorder) and lower IQ in children. Our primary objective was to examine the association between fluoride exposure and reported diagnosis of a learning disability among a population-based sample of Canadian children aged 3-12 years. We analyzed data from Cycles 2 and 3 of the Canadian Health Measures Survey. Four measures of fluoride exposure were available: 1) urinary fluoride (μmol/L), 2) creatinine-adjusted urinary fluoride (μmol/mmol), 3) specific gravity-adjusted urinary fluoride (μmol/L), and 4) fluoride concentration of tap water (mg/L) (Cycle 3 only). Diagnosis of a learning disability (yes/no) was based on parental- or self-report. Associations were examined using logistic regression (where possible), unadjusted and adjusted for covariates. When Cycles 2 and 3 were examined separately, reported learning disability diagnosis was not significantly associated with any measure of fluoride exposure in unadjusted or adjusted models. When Cycles 2 and 3 were combined, a small but statistically significant effect was observed such that children with higher urinary fluoride had higher odds of having a reported learning disability in the adjusted model (p = 0.03). However, the association was not observed in models that used creatinine-adjusted urinary fluoride and specific gravity-adjusted urinary fluoride, which are believed to be more accurate measures due to their correction for urinary dilution. Overall, there did not appear to be a robust association between fluoride exposure and parental- or self-reported diagnosis of a learning disability among Canadian children.

  14. Saliva fluoride before and during 3 years of supervised use of fluoride toothpaste.

    Science.gov (United States)

    Richards, A; Machiulskiene, V; Nyvad, B; Baelum, V

    2013-12-01

    The purpose of the study was to examine pre-brushing saliva fluoride concentrations before and during a large, 3-year, prospective toothpaste study on the effect of post-brushing rinsing on dental caries. The aims were to study saliva fluoride over time and the effect of rinsing on saliva fluoride and to relate saliva fluoride to caries increments and accumulation of plaque. Saliva samples (baseline and 1, 2, and 3 years) were collected from 11-year-old children attending two schools (A and B) in Kaunas, Lithuania, who refrained from brushing the evening and morning before saliva collection. Numbers of saliva samples collected varied from 264 at baseline to 188 at the 3-year follow-up. Children in school A rinsed with water after daily brushing, while children in school B did not rinse. Total caries and visible plaque were registered at baseline and after 3 years. Mean saliva fluoride concentrations at baseline and after 1, 2, and 3 years from school A (rinsing) were 0.014, 0.026, 0.029, and 0.034 ppm and from school B (no rinsing) were 0.013, 0.028, 0.031, and 0.031 ppm, respectively. Increases in saliva fluoride from baseline were significant (Wilcoxon's test, p Saliva fluoride did not increase beyond year 1 and did at no time point differ between schools. Reductions in numbers of tooth surfaces with dental plaque were significantly positively related to the number of caries reversals over the 3 years. Background saliva fluoride concentration is increased by brushing at least once daily on schooldays, does not increase further over 3 years, and is not affected by rinsing after brushing. Continuous use of fluoride toothpaste produces ambient saliva fluoride levels similar to saliva fluoride in areas with fluoridated water.

  15. 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.

  16. REDUCTION OF FLUORIDE TO METAL

    Science.gov (United States)

    Carlson, O.N.; Schmidt, F.A.; Spedding, F.H.

    1960-08-30

    A process is given for making yttrium metal by reducing yttrium fluoride with calcium plus magnesium. Calcium is added in an excess of from 10 to 20% and magnesium in a quantity to yield a magnesium--yttrium alloy containing from 12 to 25% magnesium when the reaction mass is heated in an inert atmosphere at from 900 to 1106 deg C, but preferably above the melting point of the alloy. Calcium chloride may be added so as to obtain a less viscous slag containing from 30 to 60% calcium chloride. After removal of the slag the alloy is vacuum-heated at about 1100 deg C for volatilization of the magnesium and calcium.

  17. Thallium-isotopic compositions of euxinic sediments as a proxy for global manganese-oxide burial

    Science.gov (United States)

    Owens, Jeremy D.; Nielsen, Sune G.; Horner, Tristan J.; Ostrander, Chadlin M.; Peterson, Larry C.

    2017-09-01

    Thallium (Tl) isotopes are a new and potentially powerful paleoredox proxy that may track bottom water oxygen conditions based on the global burial flux of manganese oxides. Thallium has a residence time of ∼20 thousand years, which is longer than the ocean mixing time, and it has been inferred that modern oxic seawater is conservative with respect to both concentration and isotopes. Marine sources of Tl have nearly identical isotopic values. Therefore, the Tl sinks, adsorption onto manganese oxides and low temperature oceanic crust alteration (the dominant seawater output), are the primary controls of the seawater isotopic composition. For relatively short-term, ∼million years, redox events it is reasonable to assume that the dominant mechanism that alters the Tl isotopic composition of seawater is associated with manganese oxide burial because large variability in low temperature ocean crust alteration is controlled by long-term, multi-million years, average ocean crust production rates. This study presents new Tl isotope data for an open ocean transect in the South Atlantic, and depth transects for two euxinic basins (anoxic and free sulfide in the water column), the Cariaco Basin and Black Sea. The Tl isotopic signature of open ocean seawater in the South Atlantic was found to be homogeneous with ε205Tl = -6.0 ± 0.3 (±2 SD, n = 41) while oxic waters from Cariaco and the Black Sea are -5.6 and -2.2, respectively. Combined with existing data from the Pacific and Arctic Oceans, our Atlantic data establish the conservatism of Tl isotopes in the global ocean. In contrast, partially- and predominantly-restricted basins reveal Tl isotope differences that vary between open-ocean (-6) and continental material (-2) ε205Tl, scaling with the degree of restriction. Regardless of the differences between basins, Tl is quantitatively removed from their euxinic waters below the chemocline. The burial of Tl in euxinic sediments is estimated to be an order of magnitude

  18. Well waters fluoride in Enugu, Nigeria.

    Science.gov (United States)

    Ogbu, I Si; Okoro, O Io; Ugwuja, E I

    2012-04-01

    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 (pwaters 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.

  19. Suicide by exposure to sulfuryl fluoride.

    Science.gov (United States)

    Scheuerman, E H

    1986-07-01

    The insecticide fumigant, sulfuryl fluoride, was used as an instrument of self destruction in at least two of the three fatal exposures detailed in this report. The autopsy findings, while nonspecific, have a confirmatory value. Toxicologic analysis should include a plasma and a urine fluoride level, since the toxic effects of exposure are probably related to this ion. Concentrations of fluoride in our cases were: 50.42 mg/L (Case 1) and 20 mg/L (Case 3). However, the values must be interpreted in light of all known information as a result of the paucity of reported cases of fatal sulfuryl fluoride exposures. The cases described provide a model for the investigation of tent fumigation deaths. Proper investigation of fumigant deaths requires knowledge of the insecticide, the fumigation procedure, and the implementation of warning devices. Guidelines are offered along with a procedural checklist for the investigation of tent fumigation deaths.

  20. Study of fluoride corrosion of nickel alloys

    Science.gov (United States)

    Gunther, W. H.; Steindler, M. J.

    1969-01-01

    Report contains the results of an investigation of the corrosion resistance of nickel and nickel alloys exposed to fluorine, uranium hexafluoride, and volatile fission product fluorides at high temperatures. Survey of the unclassified literature on the subject is included.

  1. Thallium isotopes as a potential tracer for the origin of cratonic eclogites

    Science.gov (United States)

    Nielsen, Sune G.; Williams, Helen M.; Griffin, William L.; O'Reilly, Suzanne Y.; Pearson, Norman; Viljoen, Fanus

    2009-12-01

    Cratonic eclogites are inferred to originate either from subducted ocean crust or mantle melts accreted onto the roots of continents. These models have different implications for the growth of continents, but it is currently difficult to determine the origin of individual eclogite suites. Upper ocean crust altered at low temperatures and marine sediments both display high thallium (Tl) concentrations and strongly fractionated Tl isotope signatures relative to the ambient upper mantle. In this study we carry out the first examination of the suitability of Tl isotopes as a tracer for an ocean-crust origin of cratonic eclogites. We have analysed the Tl isotope composition of clinopyroxene and garnet in six eclogites from the Kaalvallei and Bellsbank kimberlite pipes in South Africa. Minerals were pre-cleaned with an HCl leaching technique and the leachates display variably light Tl isotope ratios. These most likely reflect low-temperature hydrothermal alteration occurring after eruption of the kimberlite that carried the eclogites to the surface. The leached mineral pairs all display identical Tl isotope ratios, strongly suggesting that the source of the analysed Tl is identical for each mineral pair. It is, however, not possible to exclude the possibility that the analysed Tl originates from kimberlitic material that was not removed by the cleaning procedure. Only one of the six samples exhibits a Tl isotope composition different from ambient mantle. Assuming that the Tl isotope signatures indeed represent the eclogite minerals and not any form of contamination, the Tl isotope composition in this sample is consistent with containing a minor component (low temperatures. Thallium isotopes may become one of the most sensitive indicators for the presence of low-T altered ocean crust because of the stark contrast in Tl concentration and isotopic composition between the mantle and altered ocean crust. In fact, no other chemical or isotopic tracer could have provided an

  2. Thallium-201 SPECT in the diagnosis of head and neck cancer.

    Science.gov (United States)

    Valdés Olmos, R A; Balm, A J; Hilgers, F J; Koops, W; Loftus, B M; Tan, I B; Muller, S H; Hoefnagel, C A; Gregor, R T

    1997-06-01

    The accuracy of SPECT with 201Tl-chloride for the diagnosis of primary tumors, lymph node metastases and recurrences in head and neck cancer was evaluated for clinical applicability. SPECT images, obtained 60 min after administration of 150 MBq 201Tl-chloride, were compared with clinical, CT and/or MRI and histology results. In addition, whole-body images were obtained to detect distant metastases. In 79 patients studied for primary tumors (principally larynix, hypopharynx, oropharynx, nasopharynx and oral cavity), 201Tl SPECT correctly identified 69 of 73 (95% versus 88% for CT/MRI) histologically confirmed malignancies including 63 squamous-cell carcinomas. The method localized four occult naso- and oropharynx carcinomas not seen on CT/MRI and was correctly negative in two patients without tumor and in three of four patients with no confirmed primary tumor in the head and neck. With respect to regional spread, only patients who had cervical lymph node dissection were evaluated, and the findings were recorded per side of the neck. Thallium-201 SPECT correctly identified metastases in 31 of 36 neck dissections with proven lymph node involvement (86%), was correctly negative in nine and false-positive in one. Although the sensitivity of CT/MRI was clearly higher (97%), considerably more false-positive cases affected its accuracy (81% versus 87% for SPECT). In 30 patients investigated for recurrences, 201Tl SPECT correctly identified 27 of 29 microscopically confirmed tumor sites (93%) and was correctly negative in seven. Sensitivity of CT/MRI was lower (76%), and a greater number of false-positives (seven versus three for SPECT) further decreased its accuracy (64% versus 87% for SPECT). Distant metastases were detected in five patients. Thallium-201 SPECT appears to be an accurate method for the diagnosis of head and neck cancer. The method is particularly useful for detection of occult head and neck tumors and for assessing recurrences. It also may be of

  3. Fluoride release, recharge and mechanical property stability of various fluoride-containing resin composites.

    Science.gov (United States)

    Naoum, S; Ellakwa, A; Martin, F; Swain, M

    2011-01-01

    To determine the fluoride release and recharge of three fluoride-containing resin composites when aged in deionized water (pH 6.5) and lactic acid (pH 4.0) and to assess mechanical properties of these composites following aging. Three fluoride-containing resin composites were analyzed in this study; a new giomer material named Beautifil II, Gradia Direct X, and Tetric EvoCeram. A glass ionomer cement, Fuji IX Extra, was also analyzed for comparison. Specimens were fabricated for two test groups: group 1 included 10 disc specimens initially aged 43 days in deionized water (five specimens) and lactic acid (five specimens). The fluoride release from these specimens was measured using a fluoride-specific electrode on nine specific test days during the aging period. Following 49 days of aging, each specimen was recharged in 5000 ppm neutral sodium fluoride solution for 5 minutes. Specimen recharge was then repeated on a weekly basis for 3 weeks. The subsequent fluoride rerelease was measured at 1, 3, and 7 days after each recharge episode. Group 2 included six disc specimens aged for 3 months in deionized water (three specimens) and lactic acid (three specimens). The hardness and elastic modulus of each specimen was measured using nano-indentation at intervals of 24 hours, 1 month, and 3 months after fabrication. Two-way factorial analysis of variance (ANOVA) and post-hoc (Tukey) testing was used to assess the influence of storage media (two levels) and composite type (three levels) on the fluoride release, fluoride rerelease, hardness, and elastic modulus of the assessed materials. The level of significance was set at p=0.05. All three composites demonstrated fluoride release and recharge when aged in both deionized water and lactic acid. The cumulative fluoride released from Beautifil II into both media was substantially greater than the fluoride released from Gradia Direct X and Tetric EvoCeram after 43 days aging and was significantly (precharge ability of the three

  4. 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. 

  5. Well Waters Fluoride in Enugu, Nigeria

    Directory of Open Access Journals (Sweden)

    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.

  6. Debating Water Fluoridation Before Dr. Strangelove

    Science.gov (United States)

    2015-01-01

    In the 1930s, scientists learned that small amounts of fluoride naturally occurring in water could protect teeth from decay, and the idea of artificially adding fluoride to public water supplies to achieve the same effect arose. In the 1940s and early 1950s, a number of studies were completed to determine whether fluoride could have harmful effects. The research suggested that the possibility of harm was small. In the early 1950s, Canadian and US medical, dental, and public health bodies all endorsed water fluoridation. I argue in this article that some early concerns about the toxicity of fluoride were put aside as evidence regarding the effectiveness and safety of water fluoridation mounted and as the opposition was taken over by people with little standing in the scientific, medical, and dental communities. The sense of optimism that infused postwar science and the desire of dentists to have a magic bullet that could wipe out tooth decay also affected the scientific debate. PMID:26066938

  7. Drinking water quality and fluoride concentration.

    Science.gov (United States)

    Frazão, Paulo; Peres, Marco A; Cury, Jaime A

    2011-10-01

    This paper aimed to analyze the fluoride concentration in drinking water, taking into account the balance between the benefits and risks to health, in order to produce scientific backing for the updating of the Brazilian legislation. Systematic reviews studies, official documents and meteorological data were examined. The temperatures in Brazilian state capitals indicate that fluoride levels should be between 0.6 and 0.9 mg F/l in order to prevent dental caries. Natural fluoride concentration of 1.5 mg F/l is tolerated for consumption in Brazil if there is no technology with an acceptable cost-benefit ratio for adjusting/removing the excess. Daily intake of water with a fluoride concentration > 0.9 mg F/l presents a risk to the dentition among children under the age of eight years, and consumers should be explicitly informed of this risk. In view of the expansion of the Brazilian water fluoridation program to regions with a typically tropical climate, Ordinance 635/75 relating to fluoride added to the public water supply should be revised.

  8. Fluoride contents of some Nigerian dentifrices.

    Science.gov (United States)

    Ndiokwelu, E; Zohoori, V

    2010-06-01

    To analyze the fluoride content of different brands of toothpastes and powders commercially available in Nigerian markets, to compare the claims of the manufacturers with the objectively obtained results of the analysis and to make recommendations to the Regulatory Agencies based on the results of analysis. Standard Operating Procedures (SOP) were used to measure the concentration of fluoride in randomly selected samples using fluoride ion selective electrode. Of the twelve samples analyzed, two toothpastes were purchased at Newcastle. Ten samples (eight toothpastes and two powders) were brought over from Nigeria. Three of the twelve were found to be deficient in the quantity of fluoride contained. All the deficient three samples found wanting were from Nigeria--a thirty per cent (30%) of the Nigerian samples. The importance of fluoride in caries prevention has been well documented and appreciated as public health measure. All efforts geared towards making fluoride available to the public especially through the dentifrices should be encouraged and guarded against mercantilism and abuse. To this end, the Nigerian Dental Association and the National Agency for Food and Drug Administration and Control (NAFDAC) should increase their surveillance over the quality of the products marketed.

  9. Thallium in spawn, juveniles, and adult common toads (Bufo bufo) living in the vicinity of a zinc-mining complex, Poland.

    Science.gov (United States)

    Dmowski, Krzysztof; Rossa, Monika; Kowalska, Joanna; Krasnodębska-Ostręga, Beata

    2015-01-01

    A breeding population of the common toad Bufo bufo living in the vicinity of a Zn-Pb smelting works in Bukowno, Poland was studied for the presence of thallium. Tl concentration was measured in the bottom sediments of the spawning pond, in the laid eggs, in juveniles after metamorphosis, and in the selected tissues of the adult individuals. A very high concentration of Tl was detected in the spawn (13.97 ± 8.90 mg/kg d.w.). In 50% of the spawn samples, levels exceeded 20 mgTl/kg d.w. The issue of maternal transfer of thallium from females to oocytes is discussed. Due to a significant accumulation of thallium, spawn analysis can be used as a sensitive indicator of the presence of this element in the environment and may replace more invasive methods that involve the killing of adult animals. In those regions that are abundant in Zn-Pb ores, the spawn of amphibians may be a very important source of thallium contamination for predators. From among all tissues of the Bukowno adult toads, the livers have shown the highest accumulation of thallium (mean 3.98 mg/kg d.w. and maximum value--18.63). For as many as 96.5% of livers, concentrations exceeded 1.0 mgTl/kg d.w. which is treated as indicative of poisoning.

  10. In-situ pre-concentration through repeated sampling and pyrolysis for ultrasensitive determination of thallium in drinking water by electrothermal atomic absorption spectrometry.

    Science.gov (United States)

    Liu, Liwei; Zheng, Huaili; Xu, Bincheng; Xiao, Lang; Chigan, Yong; Zhangluo, Yilan

    2018-03-01

    In this paper, a procedure for in-situ pre-concentration in graphite furnace by repeated sampling and pyrolysis is proposed for the determination of ultra-trace thallium in drinking water by graphite furnace atomic absorption spectrometry (GF-AAS). Without any other laborious enrichment processes that routinely result in analyte loss and contamination, thallium was directly concentrated in the graphite furnace automatically and subsequently subject to analysis. The effects of several key factors, such as the temperature for pyrolysis and atomization, the chemical modifier, and the repeated sampling times were investigated. Under the optimized conditions, a limit of detection of 0.01µgL -1 was obtained, which fulfilled thallium determination in drinking water by GB 5749-2006 regulated by China. Successful analysis of thallium in certified water samples and drinking water samples was demonstrated, with analytical results in good agreement with the certified values and those by inductively coupled plasma mass spectrometry (ICP-MS), respectively. Routine spike-recovery tests with randomly selected drinking water samples showed satisfactory results of 80-96%. The proposed method is simple and sensitive for screening of ultra-trace thallium in drinking water samples. Copyright © 2017. Published by Elsevier B.V.

  11. Electrochemical Extraction of Rare Earth Metals in Molten Fluorides : Conversion of Rare Earth Oxides into Rare Earth Fluorides Using Fluoride Additives

    NARCIS (Netherlands)

    Abbasalizadeh, A.; Malfliet, Annelies; Seetharaman, Seshadri; Sietsma, J.; Yang, Y.

    2017-01-01

    In the present research on rare earth extraction from rare earth oxides (REOs), conversion of rare earth oxides into rare earth fluorides with fluoride fluxes is investigated in order to overcome the problem of low solubility of the rare earth oxides in molten fluoride salts as well as the formation

  12. Fluoride - is it capable of fighting old and new dental diseases? An overview of existing fluoride compounds and their clinical applications.

    Science.gov (United States)

    Brambilla, E

    2001-01-01

    Since researchers first became aware of the anticaries action of fluoride, they have been investigating the effect of this preventive agent in inhibiting or arresting caries development. Many forms of systemic or topical fluoride have been studied and tested for clinical application. Water, salt, milk fluoridation and the use of fluoride supplements were introduced for systemic fluoridation mainly using sodium fluoride. Solutions, gels, toothpastes and rinses of sodium fluoride, stannous fluoride, amine fluorides, acidulated phosphate fluoride and monofluorophosphate were used for topical fluoridation. More recently nonaqueous fluoride varnishes in an alcoholic solution of natural resins and difluorosilane agents in a polyurethane matrix were introduced. Although all of these fluoridation methods have a caries-preventive action, these benefits and the ease of application is variable. As fluoride is a key component of oral health promotion a coordinated approach on a community and individual basis seems to be needed to maximize the cost-benefit ratio of prevention. Copyright 2001 S. Karger AG, Basel.

  13. 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;

  14. 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

  15. Plaque formation and lactic acid production after use of amine fluoride/stannous fluoride mouthrinse

    NARCIS (Netherlands)

    Gerardu, V.A.M.; Buijs, M.; Loveren, C. van; Cate, J.M. ten

    2007-01-01

    The aim of this study was lo determine the effects of 3 wk of daily rinsing with amine fluoride/stannous fluoride (AmF/SnF2) mouthrinse on plaque formation at buccal and interproximal sites, and on the acid production in plaque. in a randomized clinical trial with 30 participants. The amount of

  16. 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.

  17. Cancer incidence and mortality in workers exposed to fluoride

    DEFF Research Database (Denmark)

    Grandjean, P; Olsen, J H; Jensen, O M

    1992-01-01

    Although a recent bioassay showed increased frequency of bone cancer in rats with high oral intake of fluoride, the data are reported as equivocal evidence of carcinogenicity. In humans, occupational fluoride exposure may cause skeletal fluorosis, and our earlier follow-up of fluoride-exposed wor......-exposed workers showed increased incidence of respiratory cancers.......Although a recent bioassay showed increased frequency of bone cancer in rats with high oral intake of fluoride, the data are reported as equivocal evidence of carcinogenicity. In humans, occupational fluoride exposure may cause skeletal fluorosis, and our earlier follow-up of fluoride...

  18. Multiple inorganic toxic substances contaminating the groundwater of Myingyan Township, Myanmar: Arsenic, manganese, fluoride, iron, and uranium

    Energy Technology Data Exchange (ETDEWEB)

    Bacquart, Thomas [Better Life Laboratories, Calais, VT (United States); Frisbie, Seth [Better Life Laboratories, Calais, VT (United States); Department of Chemistry and Biochemistry, Norwich University, Northfield, VT (United States); Mitchell, Erika [Better Life Laboratories, Calais, VT (United States); Grigg, Laurie [Department of Earth and Environmental Science, Norwich University, Northfield, VT (United States); Cole, Christopher [Department of Chemistry and Biochemistry, Norwich University, Northfield, VT (United States); Small, Colleen [Vermont Department of Health Laboratory, Burlington, VT (United States); Sarkar, Bibudhendra, E-mail: bsarkar@sickkids.ca [Department of Molecular Structure and Function, The Research Institute of The Hospital for Sick Children, University of Toronto, Toronto, Ontario (Canada); Department of Biochemistry, University of Toronto, Toronto, Ontario (Canada)

    2015-06-01

    In South Asia, the technological and societal shift from drinking surface water to groundwater has resulted in a great reduction of acute diseases due to water borne pathogens. However, arsenic and other naturally occurring inorganic toxic substances present in groundwater in the region have been linked to a variety of chronic diseases, including cancers, heart disease, and neurological problems. Due to the highly specific symptoms of chronic arsenic poisoning, arsenic was the first inorganic toxic substance to be noticed at unsafe levels in the groundwater of West Bengal, India and Bangladesh. Subsequently, other inorganic toxic substances, including manganese, uranium, and fluoride have been found at unsafe levels in groundwater in South Asia. While numerous drinking water wells throughout Myanmar have been tested for arsenic, relatively little is known about the concentrations of other inorganic toxic substances in Myanmar groundwater. In this study, we analyzed samples from 18 drinking water wells (12 in Myingyan City and 6 in nearby Tha Pyay Thar Village) and 2 locations in the Ayeyarwaddy River for arsenic, boron, barium, beryllium, cadmium, cobalt, chromium, copper, fluoride, iron, mercury, manganese, molybdenum, nickel, lead, antimony, selenium, thallium, uranium, vanadium, and zinc. Concentrations of arsenic, manganese, fluoride, iron, or uranium exceeded health-based reference values in most wells. In addition, any given well usually contained more than one toxic substance at unsafe concentrations. While water testing and well sharing could reduce health risks, none of the wells sampled provide water that is entirely safe with respect to inorganic toxic substances. It is imperative that users of these wells, and users of other wells that have not been tested for multiple inorganic toxic substances throughout the region, be informed of the need for drinking water testing and the health consequences of drinking water contaminated with inorganic toxic

  19. The ECG component of Thallium-201 exercise testing impacts on cardiac intervention rates

    Energy Technology Data Exchange (ETDEWEB)

    Deague, J.; Salehi, N.; Grigg, L.; Lichtenstein, M.; Better, N. [Royal Melbourne Hospital, Parkville, VIC (Australia). Departments of Nuclear Medicine and Cardiology

    1998-06-01

    Full text: Thallium exercise testing (Tlex) offers superior sensitivity and specificity to exercise electrocardiography (ECG), but the value of the ECG data in Tlex remains poorly studied. While a normal Tlex is associated with an excellent prognosis, patients with a positive Tlex have a higher cardiac event rate. We aimed to see if a negative ECG Component of the Tlex (ECGTl) was associated with an improved outcome compared with a positive ECGTl, in those patients with a reversible Tlex defect. We followed 100 consecutive patients retrospectively with a reversible defect on Tlex (50 with negative and 50 with positive ECGTI) for 12 months. The ECG was reviewed as positive (1mm ST depression 0.08 seconds after J point or >2mm if on digoxin or prior ECG changes), negative, equivocal or uninterpretable. We excluded patients with pharmacological testing, and those with equivocal or uninterpretable ECGs. End-points included angiography, cardiac interventions and cardiac event rate (CER) incorporating unstable angina, acute myocardial infarction, and cardiac death. In conclusion 24% of patients with reversible defects on Tlex who had a negative ECGTI still proceeded to PTCA or CABG. Those with a positive ECGTI had a higher incidence of angiography and cardiac revascularisation, but this difference was only evident in patients with mild to moderate reversibility

  20. Redox-controlled release dynamics of thallium in periodically flooded arable soil.

    Science.gov (United States)

    Antić-Mladenović, Svetlana; Frohne, Tina; Kresović, Mirjana; Stärk, Hans-Joachim; Savić, Dubravka; Ličina, Vlado; Rinklebe, Jörg

    2017-07-01

    To our knowledge, this is the first work to mechanistically study the impact of the redox potential (E H ) and principal factors, such as pH, iron (Fe), manganese (Mn), dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), chlorides (Cl - ) and sulfates (SO 4 2- ), on the release dynamics of thallium (Tl) in periodically flooded soil. We simulated flooding using an automated biogeochemical microcosm system that allows for systematical control of pre-defined redox windows. The E H value was increased mechanistically at intervals of approximately 100 mV from reducing (-211 mV) to oxidizing (475 mV) conditions. Soluble Tl levels (0.02-0.28 μg L -1 ) increased significantly with increases in E H (r = 0.80, p soils along with a determination of the Tl species and monitoring of the Tl content in plants to achieve more detailed insight into soluble Tl behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. EFFECTS OF THALLIUM ON THE LARVAL DEVELOPMENT OF LUCILIA SERICATA MEIGEN 1826 AND PMI ESTIMATION

    Directory of Open Access Journals (Sweden)

    Arif Gökhan BAŞARAN

    2011-08-01

    Full Text Available Determination of larval growth rate of and forensic analysis of the age of Calliphoridae larvae on a corpse are useful evidence in legal investigations for the estimation of exact death time and time duration after death; post mortem interval. However many factors, such as temperature, tissue type and contamination of drugs and toxins, effect larval development of blow fly larvae and consequently theestimation of post mortem interval. The present study examined the larval growth rate of a forensically important blow fly species, Lucilia sericata Meigen 1826 in different concentrations (0,12; 0,25; 0,50; 1 and 2 μg/g of toxic heavy metal Thallium under controlled laboratory conditions. Body length and weight, death ratio of larvae and pupa between experimental and control groups were compared. Results demonstrated that the development rate of larvae between uncontaminated and contaminated diets varies significantly. In short, they molted later, reached maximum length more slowly and sometimesproduced significantly smaller pupae in contaminated food source. These results emphasized that the importance of determining the contamination rate of toxins in tissue for the forensic entomologist,while using development rates from standard curves based on larvae fed non-contaminated mediums.

  2. Value of transient dilation of the left ventricular cavity on stress thallium scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Sugihara, Hiroki; Shiga, Kouji; Umamoto, Ikuo (Kyoto Prefectural Univ. of Medicine (Japan)) (and others)

    1991-02-01

    This study was undertaken to evaluate the value of transient dilation of the left ventricular cavity on stress thallium scintigraphy in 80 patients with ischemic heart disease (IHD) and 50 with hypertrophic cardiomyopathy (HCM). Twenty persons without either coronary artery stenosis or heart disease were served as controls. Areas surrounded by maximum count points on the line of each 10deg on the short axis slice through the mid-cavity of the left ventricle were obtained at 10 minutes and at 3 hours after exercise. Transient dilation index (TDI) was obtained by dividing the area on early image by that on delayed image. TDI was significantly higher in patients with two or three vessel disease in the IHD group than the control group. High TDI was observed in 8% for one vessel disease, 40% for two vessel disease, and 80% for three vessel disease, contributing to the detection of multivessel IHD. In the HCM group of 80 patients, 24 (48%) had high TDI which was frequently associated with a history of chest pain and positive ECG findings at exercise. When these 24 HCM patients underwent exercise blood pool scintiscanning, left ventricular enddiastolic volume was similar before and at 10 minutes after exercise. These findings suggest that transient dilation of the left ventricular cavity after exercise may reflect subendocardial ischemia in both IHD and HCM. TDI would become a useful indicator for transient dilation of the left ventricular cavity. (N.K.).

  3. Clinicopathologic correlation study of thallium-201 myocardial scintigraphy in diagnosis of myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Chida, Kouji; Sugiura, Masaya; Ohkawa, Shin-ichiro

    1987-05-01

    In a series of 1,000 consecutive autopsy cases, we evaluated the clinical utility of thallium-201 (Tl-201) myocardial scintigraphy and electrocardiography (ECG) in 101 patients who had been studied while alive. Fifty-five cases had myocardial infarctions (MI) at autopsy. The Tl-201 scintigram and ECG in diagnosis of MI showed sensitivities of 68 % and 60 %, specificities of 87 % and 83 %, and diagnostic accuracies of 76 % and 70 %, respectively. The sensitivity of the Tl-201 scintigram was 70 % in anterior MI, 80 % in postero-inferior MI, 25 % in lateral and subendocardial infarction. The sensitivity was 88 % for large massive MI, but was low in scattered (50 %) or middle-sized MI (17 %). The diagnostic limit of the resolution of Tl-201 scintigrams was 4.5 cm in long diameter. All 8 cases with MI of less than 4 cm could not be diagnosed with the technique. There were 48 cases of large MI (more than 5 cm), but 8 cases could not be diagnosed by scintigraphy because of non-transmural or scattered MI. A comparison of the Tl-201 scintigram and ECG showed that 27 cases out of 60 cases were diagnosed by both methods, 14 only by the Tl-201 scintigram, 9 only by ECG and 10 by neither method.

  4. Evaluation of myocardial damage in Duchenne's muscular dystrophy with thallium-201 myocardial SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, Takuhisa; Shibuya, Noritoshi (Kawatana National Hospital, Nagasaki (Japan)); Hashiba, Kunitake; Oku, Yasuhiko; Mori, Hideki; Yano, Katsusuke

    1993-01-01

    Myocardial damage and cardiopulmonary functions in patients with Duchenne's muscular dystrophy (DMD) were assessed using thallium-201 myocardial single-photon emission computed tomography (SPECT) and technetium-99m multigated radionuclide angiography. Twenty-five patients with DMD were divided into 4 groups according to percent of perfusion defect (%PD) calculated by the bull's-eye method and age. PD was detected in 24 (96.0%) of 25 patients with DMD, and it spread from the left ventricular lateral wall to the anterior wall and/or interventricular septum. PD was detected even in a 6-year-old DMD boy. Patients in Group I (%PD[>=]10% and age<15 years old) were shown to have a higher risk of left-sided heart failure without respiratory failure. Patients in Group II (%PD[>=]10 and age[>=]15) showed decreased pulmonary function and worsened arterial blood gas values as compared with Group IV (%PD<10 and age[>=]15). There was no significant difference in cardiac function among the 4 groups. It is postulated that myocardial damage in Group II patients is dependent primarily on a deficiency of dystrophin and on chronic respiratory failure, and that some of them are at risk of cardiopulmonary failure. It is concluded that myocardial SPECT is useful for the early diagnosis of myocardial damage and evaluation of cardiopulmonary function in DMD patients. (author).

  5. Role of relativity in high-pressure phase transitions of thallium.

    Science.gov (United States)

    Kotmool, Komsilp; Chakraborty, Sudip; Bovornratanaraks, Thiti; Ahuja, Rajeev

    2017-02-20

    We demonstrate the relativistic effects in high-pressure phase transitions of heavy element thallium. The known first phase transition from h.c.p. to f.c.c. is initially investigated by various relativistic levels and exchange-correlation functionals as implemented in FPLO method, as well as scalar relativistic scheme within PAW formalism. The electronic structure calculations are interpreted from the perspective of energetic stability and electronic density of states. The full relativistic scheme (FR) within L(S)DA performs to be the scheme that resembles mostly with experimental results with a transition pressure of 3 GPa. The s-p hybridization and the valence-core overlapping of 6s and 5d states are the primary reasons behind the f.c.c. phase occurrence. A recent proposed phase, i.e., a body-centered tetragonal (b.c.t.) phase, is confirmed with a small distortion from the f.c.c. phase. We have also predicted a reversible b.c.t. → f.c.c. phase transition at 800 GPa. This finding has been suggested that almost all the III-A elements (Ga, In and Tl) exhibit the b.c.t. → f.c.c. phase transition at extremely high pressure.

  6. Pit and fissure sealants or fluoride varnishes?

    Science.gov (United States)

    Paglia, L

    2016-09-01

    Despite the general advances in dental care, dental caries is still a global health problem affecting many children. Occlusal surfaces of first permanent molars are the most susceptible sites in the developing permanent dentition. Dentists should use sealants or fluoride varnish - as well as other means - to limit the onset of tooth decay. Application of sealants is a recommended procedure to prevent or control caries. Sealing occlusal surfaces of newly erupted permanent molars in children and teenagers delays caries onset up to 48 months compared with unsealed teeth. However longer follow-ups shows a reduction of the preventive effect [Tikhonova et al., 2015]. A review of 2013 pointed out how sealants are effective in high risk children, however information about the benefits of sealing in other conditions is still scant [Ahovuo-Saloranta et al., 2013]. Fluoride varnishes are frequently used to prevent early childhood caries and reduce caries increment in very young children [Weintraub et al., 2006] and in the most vulnerable populations, where the prevalence of caries is higher and specialist visits are occasional [Chu et al., 2010]. Many studies have reported the effectiveness of different types and forms of fluoride agents in preventing dental caries among children and adolescents [Divaris et al., 2013]. A review clarifies that professional application of a 5% sodium fluoride varnish leads to remineralisation of early enamel caries in children. Solutions of 38% silver diamine fluoride are effective in arresting active dentine caries [Gao et al., 2016]. The last systematic review [Ahovuo-Saloranta et al., 2016], comparing pit and fissure sealants with fluoride varnishes explains that the pooled estimate slightly favours resin sealants over fluoride varnishes at two years. At four and nine years, the only comparative study (with high drop-out rates) found more caries on fluoride-varnished occlusal surfaces than on resin-sealed surfaces. There is evidence

  7. Removal of fluoride from fluoride contaminated industrial waste water by electrolysis.

    Science.gov (United States)

    Joshi, Vijaya A; Nanoti, Madan V

    2003-01-01

    Wastewater containing fluoride are generally treated with lime or calcium salt supplemented with aluminium salts. Wastewater generated from different industries does not always behave in the same way due to the presence of interfering contaminants. A number of techniques have been developed and studied for the removal of excessive fluoride. Most of these are based on use of aluminium salt. In alum coagulation the sorption properties of product of hydrolysis of aluminium salts and capacity of fluoride for complex formation plays a very important role. These hydrolysis products of aluminium can be produced by passing direct current through aluminium electrode. The text presented in the paper deals with the various aspect of removal of fluoride by electrolysis using aluminium electrode from fluoride chemical based industrial wastewater.

  8. Global Measurements of Atmospheric Sulfuryl Fluoride

    Science.gov (United States)

    Mühle, J.; Harth, C. M.; Salameh, P.; Miller, B. R.; Weiss, R. F.; Porter, L. W.; Fraser, P. J.; Greally, B. R.; O'Doherty, S.

    2006-12-01

    Sulfuryl fluoride (SO2F2) is used increasingly as a fumigant, but information about its emissions to the atmosphere is limited. Its atmospheric fate and lifetime are uncertain, with hydrolysis in the basic surface waters of the oceans a likely dominant sink, and its roles as a greenhouse gas and as a sulfur source to the stratosphere are unknown. We present here the first results of two years of high-frequency high-precision in situ observations of sulfuryl fluoride in the AGAGE (Advanced Global Atmospheric Gases Experiment) global measurement program. At La Jolla, California, baseline conditions are rarely achieved, and pollution events of up to 1.7 ppb (the exposure limit is 5 ppm) from nearby structural fumigation are common. At the Mace Head, Ireland, and Cape Grim, Tasmania, AGAGE stations, baseline conditions are observed with mixing ratios at the beginning of 2005 of ~1.0 ppt and ~0.9 ppt, respectively. Measured growth rates at these stations are ~0.06 ppt per year and ~0.04 ppt per year, respectively. Using these preliminary results and assuming no significant emissions in the southern hemisphere, a simple 2-box model can be used to estimate the tropospheric lifetime of sulfuryl fluoride as about one and a half decades, which is substantially longer than previous industry estimates. The corresponding modeled sulfuryl fluoride flux to the troposphere is ~2 x 109 g per year. Based on these initial measurements, the current global warming contribution of sulfuryl fluoride is likely small. Although the lifetime of sulfuryl fluoride is longer than that of carbonyl sulfide, sulfuryl fluoride is likely less important as source of sulfur to the stratosphere, due to its low atmospheric mixing ratio.

  9. Chronologic Trends in Studies on Fluoride Mechanisms of Action.

    Science.gov (United States)

    Oh, H J; Oh, H W; Lee, D W; Kim, C H; Ahn, J Y; Kim, Y; Shin, H B; Kim, C Y; Park, S H; Jeon, J G

    2017-11-01

    Fluoride has been widely used for the prevention of dental caries since the mid-20th century. The aim of this study was to investigate the chronologic trends in studies on fluoride mechanisms of action against dental caries during the years 1950 to 2015. To this aim, queries such as "fluoride," "fluoride and demineralization," "fluoride and remineralization," "fluoride and (plaque or biofilms)," and "fluoride and (bacteria or microbials)" were submitted to PubMed to collect research article information, including titles, abstracts, publication dates, author affiliations, and publication journals. The article information that PubMed produced was then collected by an automatic web crawler and examined through informetrics and linguistic analyses. We found that the number of articles concerned with fluoride mechanisms of action against dental caries was 6,903 and gradually increased over time during the years 1950 to 2015. They were published by 1,136 journals-most notably, Caries Research and Journal of Dental Research. Of the articles published, those related to bacteria/microbials had a higher percentage (44%) than those dealing with plaque/biofilms, demineralization, and remineralization. With regard to the geographic distribution of authors, Europe and North America accounted for 65% of the articles during the years 1987 to 2015, although the number of authors in Asia sharply increased in recent years. Among the fluoride compounds, NaF was mentioned more frequently than SnF2, Na2PO3F, amine fluoride, and acidulated phosphate fluoride during the years 1986 to 2015. Water fluoridation received the most attention among the various fluoride application methods (toothpastes, mouthwashes, fluoride varnishes, and fluoride gels) during the same period. These results, obtained from employing informetrics and linguistic analyses, suggest that in studies on fluoride mechanisms of action, 1) the unbalanced geographic distribution of articles and 2) the heavy concentration of

  10. High thallium concentrations in soils from sites of historical Ag, Pb, and Zn mining in western Małopolska (S Poland

    Directory of Open Access Journals (Sweden)

    Woch M. W.

    2013-04-01

    Full Text Available The aim of this study was to assess thallium concentration in topsoil originating from sites of historical mining of Ag, Pb and Zn in western Małopolska (S Poland. Soil samples were collected from 63 sites, sieved, ground and digested in hot HClO4. Thallium concentration was measured with an atomic absorption spectrometer. Thallium concentrations averaged 20.84 mg kg-1 and varied from 4.42 to 49.82 mg kg-1. In all studied soils they exceeded values typical for uncontaminated soils (0.02 to 2.8 mg Tl kg-1. This indicates that Tl contamination may threaten the environment and public health. Routine monitoring of Tl contamination in southern Poland is required.

  11. Preconcentration of thallium(III) with 2,6-bis( N-phenyl carbamoyl) pyridine on microcrystalline naphthalene prior to its trace determination in human serum spectrophotometrically

    Science.gov (United States)

    Rezaei, B.; Meghdadi, S.; Majidi, N.

    2007-05-01

    A novel, simple, sensitive and effective method has been developed for preconcentration of thallium on 2,6-bis( N-phenyl carbamoyl)pyridine-naphthalene adsorbent in the pH range 5.0-10.0, prior to its spectrophotometric determination, based on the oxidation of bromopyrogallol red at λ = 518 nm. This method makes it possible to quantitize thallium in the range of 3.0 × 10 -9 to 1.0 × 10 -5 M, with a detection limit (S/N = 3) of 1.2 × 10 -9 M. This procedure has been successfully applied to determine the ultra trace levels of thallium in the environmental and biological samples, free from the interference of some diverse ions. The precision, expressed as relative standard deviation of three measurements is better than 4.17%.

  12. Molecular anions sputtered from fluorides

    CERN Document Server

    Gnaser, H

    2002-01-01

    The emission of negatively charged ions from different fluoride samples (LiF, CaF sub 2 , LaF sub 3 and HfF sub 4) induced by sputtering with a 14.5-keV Cs sup + ion beam was studied. Sputtered ions were detected in a high-sensitivity double-focusing mass spectrometer. In particular, the possible existence of small doubly charged negative molecular ions was investigated. But whereas singly charged species of the general type MF sub n sup - (where M represents a metal atom) were detected with high abundances, stable dianions were observed in an unambiguous way only for one molecule: HfF sub 6 sup 2 sup -. The flight time through the mass spectrometer of approx 35 mu s establishes a lower limit with respect to the intrinsic lifetime of this doubly charged ion. For singly charged anions abundance distributions and, in selected cases, emission-energy spectra were recorded. For two ion species (Ca sup - and HfF sub 5 sup -) isotopic fractionation effects caused by the (velocity dependent) ionization process were d...

  13. The influence of saliva on the dissolution of calcium fluoride after application of different fluoride gels in vitro.

    Science.gov (United States)

    Hellwig, Elmar; Polydorou, Olga; Lussi, Adrian; Kielbassa, Andrej M; Altenburger, Markus J

    2010-10-01

    To determine the formation and dissolution of calcium fluoride on the enamel surface after application of two fluoride gel-saliva mixtures. From each of 80 bovine incisors, two enamel specimens were prepared and subjected to two different treatment procedures. In group 1, 80 specimens were treated with a mixture of an amine fluoride gel (1.25% F-; pH 5.2; 5 minutes) and human saliva. In group 2, 80 enamel blocks were subjected to a mixture of sodium fluoride gel (1.25% F; pH 5.5; 5 minutes) and human saliva. Subsequent to fluoride treatment, 40 specimens from each group were stored in human saliva and sterile water, respectively. Ten specimens were removed after each of 1 hour, 24 hours, 2 days, and 5 days and analyzed according to potassium hydroxide-soluble fluoride. Application of amine fluoride gel resulted in a higher amount of potassium hydroxide-soluble fluoride than did sodium fluoride gel 1 hour after application. Saliva exerted an inhibitory effect according to the dissolution rate of calcium fluoride. However, after 5 days, more than 90% of the precipitated calcium fluoride was dissolved in the amine fluoride group, and almost all potassium hydroxide-soluble fluoride was lost in the sodium fluoride group. Calcium fluoride apparently dissolves rapidly, even at almost neutral pH. Considering the limitations of an in vitro study, it is concluded that highly concentrated fluoride gels should be applied at an adequate frequency to reestablish a calcium fluoride-like layer.

  14. Influences of charcoal and bamboo charcoal amendment on soil-fluoride fractions and bioaccumulation of fluoride in tea plants.

    Science.gov (United States)

    Gao, Hongjian; Zhang, Zhengzhu; Wan, Xiaochun

    2012-10-01

    High levels of fluoride in tea plants pose a potential health risk to humans who drink tea. It has been demonstrated that tea plant fluoride is closely related to the available fluoride in soil. But approaches that could be used to regulate the availability of fluoride in soil have been rarely seen. This study aims to investigate how the addition of charcoal and bamboo charcoal affected soil fluoride availability and bioaccumulation of fluoride in tea plants. In a microcosm experiment, tea plants were grown in the tea garden soil mixed with different amounts of charcoal and bamboo charcoal [that is, 0.5, 1.0, 2.5, and 5.0 % (w/w)]. Soil-fluoride fractions and fluoride accumulated in tea plants were determined using the sequential extraction and ion selective electrode method. Obtained results showed that both charcoal and bamboo charcoal additions significantly enhanced the concentrations of Fe/Mn oxide-bound fluoride, but significantly reduced the concentrations of water-soluble and exchangeable fluoride (p Charcoal and bamboo charcoal additions also significantly decreased the amounts of fluoride in tea roots and tea leaves (p charcoal and bamboo charcoal had no impacts on the tea quality, as indexed by the concentrations of polysaccharides, polyphenols, amino acids, and caffeine in tea leaves. These results suggested that application of charcoal and bamboo charcoal may provide a useful method to reduce the availability of fluoride in soil and the subsequent fluoride uptake by tea plants.

  15. Synthesis of nanocrystalline mixed metal fluorides in nonaqueous ...

    Indian Academy of Sciences (India)

    , thermal analysis, SEM and TEM. Monophasic cubic phases were obtained for the central ... The fluoride content was determined by titrimetry and found to be nearly stoichiometric. Some of these fluorides were found to be thermally stable up ...

  16. State and National Water Fluoridation System (Public Water Systems)

    Data.gov (United States)

    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...

  17. 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.

  18. Chemically modified field effect transistors with nitrite or fluoride selectivity

    NARCIS (Netherlands)

    Antonisse, M.M.G.; Ruel, Bianca H.M.; Engbersen, Johannes F.J.; Reinhoudt, David

    1998-01-01

    Polysiloxanes with different types of polar substituents are excellent membrane materials for nitrite and fluoride selective chemically modified field effect transistors (CHEMFETs). Nitrite selectivity has been introduced by incorporation of a cobalt porphyrin into the membrane; fluoride selectivity

  19. 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.

  20. 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.

  1. Biphasic thallium 201 SPECT-imaging for the noninvasive diagnosis of myocardial perfusion abnormalities in a child with Kawasaki disease--a case report

    Energy Technology Data Exchange (ETDEWEB)

    Hausdorf, G.; Nienaber, C.A.; Spielman, R.P.

    1988-02-01

    The mucocutaneous lymph node syndrome (Kawasaki disease) is of increasing importance for the pediatric cardiologist, for coronary aneurysms with the potential of thrombosis and subsequent stenosis can develop in the course of the disease. The authors report a 2 1/2-year-old female child in whom, fourteen months after the acute phase of Kawasaki disease, myocardial infarction occurred. Biphasic thallium 201 SPECT-imaging using dipyridamole depicted anterior wall ischemia and inferolateral infarction. This case demonstrates that noninvasive vasodilation-redistribution thallium 201 SPECT-imaging has the potential to predict reversible myocardial perfusion defects and myocardial necrosis, even in small infants with Kawasaki disease.

  2. Influence of the Dirac-Hartree-Fock starting potential on the parity-nonconserving electric-dipole-transition amplitudes in cesium and thallium

    Science.gov (United States)

    Perger, W. F.; Das, B. P.

    1987-01-01

    The parity-nonconserving electric-dipole-transition amplitudes for the 6s1/2-7s1/2 transition in cesium and the 6p1/2-7p1/2 transition in thallium have been calculated by the Dirac-Hartree-Fock method. The effects of using different Dirac-Hartree-Fock atomic core potentials are examined and the transition amplitudes for both the length and velocity gauges are given. It is found that the parity-nonconserving transition amplitudes exhibit a greater dependence on the starting potential for thallium than for cesium.

  3. Assessment of myocardial viability by dynamic tomographic iodine 123 iodophenylpentadecanoic acid imaging: comparison with rest-redistribution thallium 201 imaging.

    Science.gov (United States)

    Iskandrian, A S; Powers, J; Cave, V; Wasserleben, V; Cassell, D; Heo, J

    1995-01-01

    This study examined the ability of dynamic 123I-labeled iodophenylpentadecanoic acid (IPPA) imaging to detect myocardial viability in patients with left ventricular (LV) dysfunction caused by coronary artery disease. Serial 180-degree single-photon emission computed tomographic (SPECT) images (five sets, 8 minutes each) were obtained starting 4 minutes after injection of 2 to 6 mCi 123I at rest in 21 patients with LV dysfunction (ejection fraction [EF] 34% +/- 11%). The segmental uptake was compared with that of rest-redistribution 201Tl images (20 segments/study). The number of perfusion defects (reversible and fixed) was similar by IPPA and thallium (11 +/- 5 vs 10 +/- 5 segments/patient; difference not significant). There was agreement between IPPA and thallium for presence or absence (kappa = 0.78 +/- 0.03) and nature (reversible, mild fixed, or severe fixed) of perfusion defects (kappa = 0.54 +/- 0.04). However, there were more reversible IPPA defects than reversible thallium defects (7 +/- 4 vs 3 +/- 4 segments/patient; p = 0.001). In 14 patients the EF (by gated pool imaging) improved after coronary revascularization from 33% +/- 11% to 39% +/- 12% (p = 0.002). The number of reversible IPPA defects was greater in the seven patients who had improvement in EF than in the patients without such improvement (10 +/- 4 vs 5 +/- 4 segments/patient; p = 0.075). 123I-labeled IPPA SPECT imaging is a promising new technique for assessment of viability. Reversible defects predict recovery of LV dysfunction after coronary revascularization.

  4. Investigation of Chemical Durability Mechanisms and Structure of Fluoride Glasses.

    Science.gov (United States)

    1988-03-01

    were analysed by plasma -30 -25 -.0 -15 -10 -05 0 emission spectroscopy and the fluoride anions by log (time in daysi potentiometry with a F...glass - 4. surface during the corrosion. Fluoride ion concentration . 4 was measured from potentiometry by using fluoride ion -, selective electrodes...each raw material was measured by potentiometry with a pH electrode. Excess amount of each fluoride compound was also put in different pH buffer

  5. Fluoridation Status of U. S. Army Conus Installations

    Science.gov (United States)

    1993-09-30

    water source and date the water was analyzed. 3. The process of fluoridating or defluoridating water . a. Are chemicals used in the fluoridation... defluoridated ? Some installations are supplied water which is naturally fluoridated above optimal limits and there is need to remove a portion of the...Seven reported using no chemicals with 4 recording below 0.7 ppm levels of fluoride in the drinking water . Defluoridation was used at two installations

  6. Self-propagating high-temperature synthesis (SHS) and microwave-assisted combustion synthesis (MACS) of the thallium superconducting phases

    Science.gov (United States)

    Bayya, S. S.; Snyder, R. L.

    1994-05-01

    This paper explores the speed of reaction as a parameter to minimizing thallium loss. Self-propagating high-temperature synthesis (SHS) and microwave-assisted combustion synthesis (MACS) were developed for the synthesis of Tl-2212 and Tl-2223 superconductors using Cu metal powder as a fuel. A kitchen microwave oven was used to carry out MACS reactions. The samples were reacted for few seconds and led to the formation of the superconducting phases. Further explorations and modifications in the processing could lead to the formation of single phases by MACS.

  7. Tracking along-arc sediment inputs to the Aleutian arc using thallium isotopes

    Science.gov (United States)

    Nielsen, Sune G.; Yogodzinski, Gene; Prytulak, Julie; Plank, Terry; Kay, Suzanne M.; Kay, Robert W.; Blusztajn, Jerzy; Owens, Jeremy D.; Auro, Maureen; Kading, Tristan

    2016-05-01

    Sediment transport from the subducted slab to the mantle wedge is an important process in understanding the chemical and physical conditions of arc magma generation. The Aleutian arc offers an excellent opportunity to study sediment transport processes because the subducted sediment flux varies systematically along strike (Kelemen et al., 2003) and many lavas exhibit unambiguous signatures of sediment addition to the sub-arc mantle (Morris et al., 1990). However, the exact sediment contribution to Aleutian lavas and how these sediments are transported from the slab to the surface are still debated. Thallium (Tl) isotope ratios have great potential to distinguish sediment fluxes in subduction zones because pelagic sediments and low-temperature altered oceanic crust are highly enriched in Tl and display heavy and light Tl isotope compositions, respectively, compared with the upper mantle and continental crust. Here, we investigate the Tl isotope composition of lavas covering almost the entire Aleutian arc a well as sediments outboard of both the eastern (DSDP Sites 178 and 183) and central (ODP Hole 886C) portions of the arc. Sediment Tl isotope compositions change systematically from lighter in the Eastern to heavier in the Central Aleutians reflecting a larger proportion of pelagic sediments when distal from the North American continent. Lavas in the Eastern and Central Aleutians mirror this systematic change to heavier Tl isotope compositions to the west, which shows that the subducted sediment composition is directly translated to the arc east of Kanaga Island. Moreover, quantitative mixing models of Tl and Pb, Sr and Nd isotopes reveal that bulk sediment transfer of ∼0.6-1.0% by weight in the Eastern Aleutians and ∼0.2-0.6% by weight in the Central Aleutians can account for all four isotope systems. Bulk mixing models, however, require that fractionation of trace element ratios like Ce/Pb, Cs/Tl, and Sr/Nd in the Central and Eastern Aleutians occurs after

  8. Controls on thallium uptake during hydrothermal alteration of the upper ocean crust

    Science.gov (United States)

    Coggon, Rosalind M.; Rehkämper, Mark; Atteck, Charlotte; Teagle, Damon A. H.; Alt, Jeffrey C.; Cooper, Matthew J.

    2014-11-01

    Hydrothermal circulation is a fundamental component of global biogeochemical cycles. However, the magnitude of the high temperature axial hydrothermal fluid flux remains disputed, and the lower temperature ridge flank fluid flux is difficult to quantify. Thallium (Tl) isotopes behave differently in axial compared to ridge flank systems, with Tl near-quantitatively stripped from the intrusive crust by high temperature hydrothermal reactions, but added to the lavas during low temperature reaction with seawater. This contrasting behavior provides a unique approach to determine the fluid fluxes associated with axial and ridge flank environments. Unfortunately, our understanding of the Tl isotopic mass balance is hindered by poor knowledge of the mineralogical, physical and chemical controls on Tl-uptake by the ocean crust. Here we use analyses of basaltic volcanic upper crust from Integrated Ocean Drilling Program Hole U1301B on the Juan de Fuca Ridge flank, combined with published analyses of dredged seafloor basalts and upper crustal basalts from Holes 504B and 896A, to investigate the controls on Tl-uptake by mid-ocean ridge basalts and evaluate when in the evolution of the ridge flank hydrothermal system Tl-uptake occurs. Seafloor basalts indicate an association between basaltic uptake of Tl from cold seawater and uptake of Cs and Rb, which are known to partition into K-rich phases. Although there is no clear relationship between Tl and K contents of seafloor basalts, the data do not rule out the incorporation of at least some Tl into the same minerals as the alkali elements. In contrast, we find no relationship between the Tl content and either the abundance of secondary phyllosilicate minerals, or the K, Cs or Rb contents in upper crustal basalts. We conclude that the uptake of Tl and alkali elements during hydrothermal alteration of the upper crust involves different processes and/or mineral phases compared to those that govern seafloor weathering. Furthermore

  9. Spatial analysis of fluoride concentrations in drinking water and ...

    African Journals Online (AJOL)

    Namibia, the driest country in sub-Saharan Africa, is largely reliant on groundwater for its potable water demand and groundwater is a major source of naturally-occurring fluoride. This study assessed the spatial distribution of fluoride in potable water and appraised the population at risk for high fluoride intake. Analysis of ...

  10. Modelling the Effects of Competing Anions on Fluoride Removal by ...

    African Journals Online (AJOL)

    Fe2O3 nano particles supported on functionalized poly-acrylonitrile was prepared. PAN-oxime-nano Fe2O3 was characterized by XRD, FTIR andTEMand used for fluoride adsorption. The adsorption capacity increased with increasing initial fluoride concentration and reaction time. Fluoride-removal performance of ...

  11. Fluoride concentrations in groundwater and impact on human health ...

    African Journals Online (AJOL)

    Temperature and pH were measured in the field while fluoride and calcium in groundwater were analysed in the laboratory. A survey was conducted to obtain information on the impact of fluoride on human health. 40% of the households and 1 primary school in Siloam Village were interviewed. Fluoride concentrations in ...

  12. Geographical mapping of fluoride levels in drinking water sources in ...

    African Journals Online (AJOL)

    Background: Knowledge of fluoride levels in drinking water is of importance in dental public health, yet this information is lacking, at national level, in Nigeria. Objective: To map out fluoride levels in drinking water sources in Nigeria. Materials and Methods: Fluoride levels in drinking water sources from 109 randomly ...

  13. Fluoride removal from aqueous solution by pumice: case study on ...

    African Journals Online (AJOL)

    The fluoride removal from synthetic water by pumice was studied at batch experiments in this study. The effect of pH, contact time, fluoride concentration and adsorbent dose on the fluoride sequestration was investigated. The optimum conditions were studied on Kuhbonan water as a case study. The results showed that ...

  14. COMPLEX FLUORIDES OF PLUTONIUM AND AN ALKALI METAL

    Science.gov (United States)

    Seaborg, G.T.

    1960-08-01

    A method is given for precipitating alkali metal plutonium fluorides. such as KPuF/sub 5/, KPu/sub 2/F/sub 9/, NaPuF/sub 5/, and RbPuF/sub 5/, from an aqueous plutonium(IV) solution by adding hydrogen fluoride and alkali-metal- fluoride.

  15. comparative study of fluoride in alcornea cordifolia and commercial ...

    African Journals Online (AJOL)

    Quantum

    2013-07-31

    Jul 31, 2013 ... cleaning the teeth was by chewing a stick. Alcornea cordifolia is the most widely chewed tooth-cleaning stick and has continued to be used despite availability of varieties of commercial .... Salivary fluoride content after tooth brushing a sodium fluoride and an amine fluoride dentifrice followed by different.

  16. 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 ... A statistical analysis of variance at 95% confidence level for fluoride determination indicated significant difference between the mean of each variety of rice samples.

  17. 21 CFR 177.2510 - Polyvinylidene fluoride resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyvinylidene fluoride resins. 177.2510 Section... as Components of Articles Intended for Repeated Use § 177.2510 Polyvinylidene fluoride resins. Polyvinylidene fluoride resins may be safely used as articles or components of articles intended for repeated use...

  18. The accuracy of fluoride measurement in water and its implications ...

    African Journals Online (AJOL)

    The accurate measurement of the fluoride concentration in water is an essential prerequisite to stay within the allowable dosing tolerances required by the South African water fluoridation legislation. In the absence of reliable error estimates for fluoride measurement in natural water samples, a study was conducted utilising ...

  19. An inter-laboratory comparative study of fluoride determination in ...

    African Journals Online (AJOL)

    South Africa is on the brink of implementation of mandatory fluoridation of municipal water following the final approval by Parliament in 2001. The ability to accurately measure fluoride in water is an obvious prerequisite for the safe and effective implementation of water fluoridation. This paper evaluates the current status of ...

  20. Fluoride distribution in different environmental segments at Hirakud ...

    African Journals Online (AJOL)

    Fluoride distribution in different environmental segments at Hirakud Orissa (India) ... African Journal of Environmental Science and Technology ... A detailed investigation undertaken during 2005 - 2006 on fluoride status of Hirakud environment reveals that the fluoride content varied from a minimum of 0.5 to a maximum of ...

  1. 40 CFR 60.212 - Standard for fluorides.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for fluorides. 60.212 Section... Industry: Superphosphoric Acid Plants § 60.212 Standard for fluorides. (a) On and after the date on which... facility any gases which contain total fluorides in excess of 5.0 g/megagram (Mg) of equivalent P2O5 feed...

  2. 40 CFR 60.222 - Standard for fluorides.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for fluorides. 60.222 Section... Industry: Diammonium Phosphate Plants § 60.222 Standard for fluorides. (a) On and after the date on which... facility any gases which contain total fluorides in excess of 30 g/megagram (Mg) of equivalent P2O5 feed (0...

  3. 40 CFR 60.232 - Standard for fluorides.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for fluorides. 60.232 Section... Industry: Triple Superphosphate Plants § 60.232 Standard for fluorides. On and after the date on which the... gases which contain total fluorides in excess of 100 g/megagram (Mg) of equivalent P2O5 feed (0.20 lb...

  4. 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.

  5. Modelling the Effects of Competing Anions on Fluoride Removal by ...

    African Journals Online (AJOL)

    NICOLAAS

    Fe2O3 nano particles supported on functionalized poly-acrylonitrile was prepared. PAN-oxime-nano Fe2O3 was characterized by. XRD, FTIR and TEM and used for fluoride adsorption. The adsorption capacity increased with increasing initial fluoride concen- tration and reaction time. Fluoride-removal performance of ...

  6. Fluoride in drinking water and its removal.

    Science.gov (United States)

    Meenakshi; Maheshwari, R C

    2006-09-01

    Excessive fluoride concentrations have been reported in groundwaters of more than 20 developed and developing countries including India where 19 states are facing acute fluorosis problems. Various technologies are being used to remove fluoride from water but still the problem has not been rooted out. In this paper, a broad overview of the available technologies for fluoride removal and advantages and limitations of each one have been presented based on literature survey and the experiments conducted in the laboratory with several processes. It has been concluded that the selection of treatment process should be site specific as per local needs and prevailing conditions as each technology has some limitations and no one process can serve the purpose in diverse conditions.

  7. Chemistry and phase evolution during roasting of toxic thallium-bearing pyrite.

    Science.gov (United States)

    Lopez-Arce, Paula; Garcia-Guinea, Javier; Garrido, Fernando

    2017-08-01

    In the frame of a research project on microscopic distribution and speciation of geogenic thallium (Tl) from contaminated mine soils, Tl-bearing pyrite ore samples from Riotinto mining district (Huelva, SW Spain) were experimentally fired to simulate a roasting process. Concentration and volatility behavior of Tl and other toxic heavy metals was determined by quantitative ICP-MS, whereas semi-quantitative mineral phase transitions were identified by in situ thermo X-Ray Diffraction (HT-XRD) and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS) analyses after each firing temperature. Sample with initial highest amount of quartz (higher Si content), lowest quantity of pyrite and traces of jarosite (lower S content) developed hematite and concentrated Tl (from 10 up to 72 mg kg-1) after roasting at 900 °C in an oxidizing atmosphere. However, samples with lower or absent quartz content and higher pyrite amount mainly developed magnetite, accumulating Tl between 400 and 500 °C and releasing Tl from 700 up to 900 °C (from 10-29 mg kg-1 down to 4-1 mg kg-1). These results show the varied accumulative, or volatile, behaviors of one of the most toxic elements for life and environment, in which oxidation of Tl-bearing Fe sulfides produce Fe oxides wastes with or without Tl. The initial chemistry and mineralogy of pyrite ores should be taken into account in coal-fired power stations, cement or sulfuric acid production industry involving pyrite roasting processes, and steel, brick or paint industries, which use iron ore from roasted pyrite ash, where large amounts of Tl entail significant environmental pollution. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Measurement of the parity nonconserving neutral weak interaction in atomic thallium

    Energy Technology Data Exchange (ETDEWEB)

    Bucksbaum, P.H.

    1980-11-01

    This thesis describes an experiment to measure parity nonconservation in atomic thallium. A frequency doubled, flashlamp pumped tunable dye laser is used to excite the 6P/sub 1/2/(F = 0) ..-->.. 7P/sub 1/2/(F = 1) transition at 292.7 nm, with circularly polarized light. An electrostatic field E of 100 to 300 V/cm causes this transition to occur via Stark induced electric dipole. Two field free transitions may also occur: a highly forbidden magnetic dipole M, and a parity nonconserving electric dipole epsilon/sub P/. The latter is presumed to be due to the presence of a weak neutral current interaction between the 6p valence electron and the nucleus, as predicted by gauge theories which unite the electromagnetic and weak interactions. Both M and epsilon/sub P/ interfere with the Stark amplitude ..beta..E to produce a polarization of the 7P/sub 1/2/ state. This is measured with a circularly polarized infrared laser beam probe, tuned to the 7P/sub 1/2/ ..-->.. 8S/sub 1/2/ transition. This selectively excites m/sub F/ = +1 or -1 components of the 7P/sub 1/2/ state, and the polarization is seen as an asymmetry in 8S ..-->.. 6P/sub 3/2/ fluorescence when the probe helicity is reversed. The polarization due to M is ..delta../sub M/ = -2M/(BETAE). It is used to calibrate the analyzing efficiency. The polarization due to epsilon/sub P/ is ..delta../sub P/ = 2i epsilon/sub P//(..beta..E), and can be distinguished from ..delta../sub M/ by its properties under reversal of the 292.7 nm photon helicity and reversal of the laser direction. A preliminary measurement yielded a parity violation in agreement with the gauge theory of Weinberg and Salam.

  9. MRI and thallium-201 SPECT in the prediction of survival in glioma

    Energy Technology Data Exchange (ETDEWEB)

    Vos, Maaike J. [VU University Medical Center, Department of Neurology, Amsterdam (Netherlands); Medical Center Haaglanden, Department of Neurology, PO Box 432, The Hague (Netherlands); Berkhof, Johannes [VU University Medical Center, Department of Epidemiology and Biostatistics, Amsterdam (Netherlands); Hoekstra, Otto S. [VU University Medical Center, Department of Nuclear Medicine and PET Research, Amsterdam (Netherlands); Bosma, Ingeborg; Sizoo, Eefje M.; Heimans, Jan J.; Reijneveld, Jaap C.; Postma, Tjeerd J. [VU University Medical Center, Department of Neurology, Amsterdam (Netherlands); Sanchez, Esther [VU University Medical Center, Department of Radiology, Amsterdam (Netherlands); Lagerwaard, Frank J. [VU University Medical Center, Department of Radiation Oncology, Amsterdam (Netherlands); Buter, Jan [VU University Medical Center, Department of Medical Oncology, Amsterdam (Netherlands); Noske, David P. [VU University Medical Center, Department of Neurosurgery and Neuro-Oncology Research Group, Amsterdam (Netherlands)

    2012-06-15

    This paper aims to study the value of MRI and Thallium 201 ({sup 201}Tl) single-photon emission computed tomography (SPECT) in the prediction of overall survival (OS) in glioma patients treated with temozolomide (TMZ) and to evaluate timing of radiological follow-up. We included patients treated with TMZ chemoradiotherapy for newly diagnosed glioblastoma multiforme (GBM) and with TMZ for recurrent glioma. MRIs and {sup 201}Tl SPECTs were obtained at regular intervals. The value of both imaging modalities in predicting OS was examined using Cox regression analyses. Altogether, 138 MRIs and 113 {sup 201}Tl SPECTs in 46 patients were performed. Both imaging modalities were strongly related to OS (P {<=} 0.02). In newly diagnosed GBM patients, the last follow-up MRI (i.e., after six adjuvant TMZ courses) and SPECT (i.e., after three adjuvant TMZ courses) were the strongest predictors of OS (P = 0.01). In recurrent glioma patients, baseline measurements appeared to be the most predictive of OS (P < 0.01). The addition of one imaging modality to the other did not contribute to the prediction of OS. Both MRI and {sup 201}Tl SPECT are valuable in the prediction of OS. It is adequate to restrict to one of both modalities in the radiological follow-up during treatment. In the primary GBM setting, MRI after six adjuvant TMZ courses contributes significantly to the prediction of survival. In the recurrent glioma setting, baseline MRI appears to be a powerful predictor of survival, whereas follow-up MRIs during TMZ seem to be of little additional value. (orig.)

  10. Synthesis, calorimetric, structural and conductivity studies in a new thallium selenate tellurate adduct compound

    Energy Technology Data Exchange (ETDEWEB)

    Ktari, L. [Laboratoire de l' Etat Solide (LES), Faculte des Sciences de Sfax, 3000 Sfax (Tunisia); Abdelhedi, M. [Laboratoire de l' Etat Solide (LES), Faculte des Sciences de Sfax, 3000 Sfax (Tunisia); Laboratoire Leon Brouillon LLB, CEA Saclay, 91191 Gif-Sur-Yvette Cedex (France); Bouhlel, N. [Laboratoire de l' Etat Solide (LES), Faculte des Sciences de Sfax, 3000 Sfax (Tunisia); Dammak, M., E-mail: meddammak@yahoo.fr [Laboratoire de l' Etat Solide (LES), Faculte des Sciences de Sfax, 3000 Sfax (Tunisia); Cousson, A. [Laboratoire Leon Brouillon LLB, CEA Saclay, 91191 Gif-Sur-Yvette Cedex (France)

    2009-08-05

    The crystal structure of the thallium selenate tellurate Tl{sub 2}SeO{sub 4}.Te(OH){sub 6} (TlSeTe) was determined by X-ray diffraction method. The title compound crystallizes in the monoclinic system with P2{sub 1}/c space group. The following parameters are: a = 12.358(3) A; b = 7.231(1) A; c = 11.986(2) A; {beta} = 111.092(2){sup o}; Z = 4. The structure can be regarded as being built of isolated TeO{sub 6} octahedra and SeO{sub 4} tetrahedra. The Tl{sup +} cations are intercalated between these kinds of polyhedra. The main feature of this structure is the coexistence of two different and independent anions (SeO{sub 4}{sup 2-} and TeO{sub 6}{sup 6-}) in the same unit cell. The structure is stable due to O-H...O hydrogen bonds which link tetrahedral and octahedral groups. Crystals of Tl{sub 2}SeO{sub 4}.Te(OH){sub 6} undergo three endothermal transitions at 373, 395 and 437 K. These transitions are detected by DSC and analyzed by dielectric measurements with impedance spectroscopy. The evolution of conductivity versus temperature showed the presence of a protonic conduction phase transition at 437 K. The phase transition at 373 K can be related to a structural phase transition, whereas the one at 395 K is ascribed as likely due to a ferroelectric-paraelectric phase transition.

  11. Electrochemical properties of modified copper-thallium hexacyanoferrate electrode in the presence of different univalent cations

    Energy Technology Data Exchange (ETDEWEB)

    Rutkowska, Iwona A.; Stroka, Jadwiga [Department of Chemistry, University of Warsaw, Pasteura 1, PL-02-093 Warsaw (Poland); Galus, Zbigniew [Department of Chemistry, University of Warsaw, Pasteura 1, PL-02-093 Warsaw (Poland)], E-mail: zbgalus@chem.uw.edu.pl

    2008-04-20

    The preparation of copper(II) hexacyanoferrate (CuHCF) films on the surface of gold electrodes as well as their characterization in solutions of various alkali metal and NH{sub 4}{sup +} cations and in the presence of thallium(I) are described. The electrochemical quartz crystal microbalance and cyclic voltammetric techniques were used. In 0.50 M lithium nitrate, even at submillimolar concentration of Tl(I), the formal potential of CuHCF was shifted to more positive values. At higher Tl(I) concentrations, the formal potential of the CuHCF redox reaction changed linearly with the logarithm of Tl(I) concentration (in the 0.50 M solution of lithium or another alkali metal nitrate). From such dependencies, selectivity coefficients K{sub Tl/M} were calculated, and they show that the CuHCF film on the gold electrode interacts preferentially with Tl(I). High affinity of Tl(I) to copper hexacyanoferrate, that was observed in the presence of alkali metal cations, was explained by relatively strong donor-acceptor interactions of Tl(I) ions with nitrogen in CN groups of the CuHCF film. It was also shown for simple M{sub 4}[Fe(CN){sub 6}] metal ferrocyanate salts (where M = Li{sup +}, Na{sup +}, K{sup +}, Rb{sup +}, Cs{sup +} and Tl{sup +}) that there is a preferential interaction of Tl{sup +} with CN group consistent with formation of a Tl-NC-Fe bridge.

  12. Quantitative evaluation of thallium-201 myocardial scintigram in coronary artery diseases

    Energy Technology Data Exchange (ETDEWEB)

    Mikada, Ken-etsu (Akita Univ. (Japan). School of Medicine)

    1992-11-01

    Quantitative indices from circumferential profile curves of thallium-201 ([sup 201]Tl) myocardial scintigram were evaluated for diagnostic utility in coronary artery diseases (CAD). Myocardial [sup 201]Tl scintigrams with single photon emission computed tomography (SPECT) were obtained 5 minutes (early) and 4 hours (delayed) after exercise in 20 normal subjects and 66 cases of CAD, of which 20 were angina pectoris without myocardial infarction (AP), 14 were subendocardial infarction (non-QMI) and 32 were Q-wave infarction (QMI). Tl counts, %Tl uptake and washout ratio (WR) were measured in 81 segments (9 apical segments of the slice from the longitudinal axis and all 72 segments of two slices from the short axis). A mean early defect (MED), a mean delayed defect (MDD), a mean delta washout rate (MDR), and a [Sigma] delayed defect ([Sigma]DD) were calculated from the areas which were below the two standard deviations of the mean %Tl uptake in normal subjects. A mean filling-in (MFI) was calculated from the difference of the %Tl uptake between early and delayed curves in each patient. In patients with CAD, the MED and MFI were higher, but MDW was lower with a more severe coronary stenosis, indicating that these indices were useful to detect myocardial hypo-perfuion. In severely stenotic regions, the MDD was higher in QMI than in AP and non-QMI, indicating that the ratio of infarct to the myocardium in the region was higher in QMI. In QMI, [Sigma]DD correlated well (r=0.723) with Total Wall Motion Scores with two-dimentional echocardiography which was directly related with infarct size. Further, MED, MFI and MDW were improved after aortocoronary bypass only in patients with patent graft. It is concluded that this quantitative evaluation with [sup 201]Tl-SPECT can provide an objective and quantitative estimate of regional myocardial ischemia and infarct. (author).

  13. Thallium-201 for cardiac stress tests: residual radioactivity worries patients and security.

    Science.gov (United States)

    Geraci, Matthew J; Brown, Norman; Murray, David

    2012-12-01

    A 47-year-old man presented to the Emergency Department (ED) in duress and stated he was "highly radioactive." There were no reports of nuclear disasters, spills, or mishaps in the local area. This report discusses the potential for thallium-201 (Tl-201) patients to activate passive radiation alarms days to weeks after nuclear stress tests, even while shielded inside industrial vehicles away from sensors. Characteristics of Tl-201, as used for medical imaging, are described. This patient was twice detained by Homeland Security Agents and searched after he activated radiation detectors at a seaport security checkpoint. Security agents deemed him not to be a threat, but they expressed concern regarding his health and level of personal radioactivity. The patient was subsequently barred from his job and sent to the hospital. Tl-201 is a widely used radioisotope for medical imaging. The radioactive half-life of Tl-201 is 73.1h, however, reported periods of extended personal radiation have been seen as far out as 61 days post-administration. This case describes an anxious, but otherwise asymptomatic patient presenting to the ED with detection of low-level personal radiation. Documentation should be provided to and carried by individuals receiving radionuclides for a minimum of five to six half-lives of the longest-lasting isotope provided. Patients receiving Tl-201 should understand the potential for security issues; reducing probable tense moments, confusion, and anxiety to themselves, their employers, security officials, and ED staff. Copyright © 2012 Elsevier Inc. All rights reserved.

  14. Usefulness of thallium-201 SPECT in the evaluation of tumor natures in intracranial meningiomas

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Tetsuji; Nakano, Takahiro; Asano, Kenichiroh; Shimamura, Norihito; Ohkuma, Hiroki [Hirosaki University Graduate School of Medicine, Department of Neurosurgery, Hirosaki (Japan)

    2011-11-15

    Although intracranial meningiomas are regarded as benign tumors, some of them behave clinically as malignant tumors. Past reports suggest that MIB 1 and vascular endothelial growth factor (VEGF) in postoperative tumor specimens correlate with the aggressive nature of tumors, but preoperative prediction of such a nature is more useful for therapeutic planning for the tumor. The purpose of this study was to assess the usefulness of preoperative thallium-201 chloride single-photon emission computed tomography (Tl SPECT) to evaluate biological behavior in intracranial meningiomas. Tl SPECT was performed on 39 patients with intracranial meningioma and Tl uptake indices were calculated. The difference in the Tl uptake index between atypical meningiomas and other pathological types of meningioma was evaluated. Moreover, correlation of Tl uptake indices with the MIB1 labeling index was estimated. Tl uptake indices were also compared between VEGF strongly positive and weakly positive meningiomas. The delayed index of atypical meningioma was significantly higher than that of the other pathological types (p = 0.036). Significant correlation was found between the Tl uptake index in the delayed image and MIB1 labeling index (p < 0.0001, R{sup 2} = 0.36). Moreover, VEGF strongly positive meningiomas exhibited a significantly higher Tl uptake index compared to VEGF weakly positive meningiomas in both the early image and the delayed image (p = 0.029, 0.023, respectively). Tl uptake index may be a possible preoperative surrogate marker of MIB1 and VEGF that is useful in detecting aggressive natures in intracranial meningiomas. (orig.)

  15. Effective removal of trace thallium from surface water by nanosized manganese dioxide enhanced quartz sand filtration.

    Science.gov (United States)

    Huangfu, Xiaoliu; Ma, Chengxue; Ma, Jun; He, Qiang; Yang, Chun; Zhou, Jian; Jiang, Jin; Wang, Yaan

    2017-12-01

    Thallium (Tl) has drawn wide concern due to its high toxicity even at extremely low concentrations, as well as its tendency for significant accumulation in the human body and other organisms. The need to develop effective strategies for trace Tl removal from drinking water is urgent. In this study, the removal of trace Tl (0.5 μg L -1 ) by conventional quartz sand filtration enhanced by nanosized manganese dioxide (nMnO 2 ) has been investigated using typical surface water obtained from northeast China. The results indicate that nMnO 2 enhanced quartz sand filtration could remove trace Tl(I) and Tl(III) efficiently through the adsorption of Tl onto nMnO 2 added to a water matrix and onto nMnO 2 attached on quartz sand surfaces. Tl(III)-HA complexes might be responsible for higher residual Tl(III) in the effluent compared to residual Tl(I). Competitive Ca 2+ cations inhibit Tl removal to a certain extent because the Ca 2+ ions will occupy the Tl adsorption site on nMnO 2 . Moreover, high concentrations of HA (10 mgTOC L -1 ), which notably complexes with and dissolves nMnO 2 (more than 78%), resulted in higher residual Tl(I) and Tl(III). Tl(III)-HA complexes might also enhance Tl(III) penetration to a certain extent. Additionally, a higher pH level could enhance the removal of trace Tl from surface water. Finally, a slight increase of residual Tl was observed after backwash, followed by the reduction of the Tl concentration in the effluent to a "steady" state again. The knowledge obtained here may provide a potential strategy for drinking water treatment plants threatened by trace Tl. Copyright © 2017. Published by Elsevier Ltd.

  16. Fluoride removal using lanthanum incorporated chitosan beads.

    Science.gov (United States)

    Bansiwal, Amit; Thakre, Dilip; Labhshetwar, Nitin; Meshram, Siddharth; Rayalu, Sadhana

    2009-11-01

    Highly selective material based on naturally occurring biomaterial namely chitosan has been designed for the defluoridation of water. Lanthanum incorporated chitosan beads (LCB) were prepared using precipitation method. The synthesis was optimized by varying different synthesis parameters namely lanthanum loading, complexation and precipitation time, strength of ammonia solution used for precipitation, drying time, etc. Lanthanum incorporated chitosan beads were characterized using SEM, FTIR, XRD and EDX. Surface area of LCB was observed to be 2.76 m(2)g(-1). The equilibrium adsorption data fitted well to Langmuir adsorption isotherm and showing maximum fluoride adsorption capacity of 4.7 mg g(-1) with negligible lanthanum release. Kinetic study reveals that adsorption of fluoride is fast and follows pseudo-first-order kinetics. The effect of pH was also studied and the best efficiency was observed at pH 5. Presence of sulphate, nitrate and chloride marginally affected the removal efficiency, however drastic reduction in fluoride uptake was observed in the presence of carbonate and bicarbonate. Negative value of change in free energy (DeltaG degrees) and positive value of change in entropy (DeltaS degrees) suggest the adsorption of fluoride by LCB is feasible and spontaneous process. Positive value of change in enthalpy (DeltaH degrees) suggests the process of fluoride adsorption is endothermic in nature. Regeneration study reveals that 1M ammonium chloride solution appears to be the promising regeneration media showing 81.22% regeneration. The adsorption capacity of LCB was similar in fluoride-contaminated ground water collected from Dhar district of Madhya Pradesh, India, as compared to simulated water.

  17. Reconstructing temporal variation of fluoride uptake in eastern grey kangaroos (Macropus giganteus) from a high-fluoride area by analysis of fluoride distribution in dentine.

    Science.gov (United States)

    Kierdorf, Horst; Rhede, Dieter; Death, Clare; Hufschmid, Jasmin; Kierdorf, Uwe

    2016-04-01

    Trace element profiling in the incrementally formed dentine of mammalian teeth can be applied to reconstruct temporal variation of incorporation of these elements into the tissue. Using an electron microprobe, this study analysed fluoride distribution in dentine of first and third mandibular molars of free-ranging eastern grey kangaroos inhabiting a high-fluoride area, to assess temporal variation in fluoride uptake of the animals. Fluoride content in the early-formed dentine of first molars was significantly lower than in the late-formed dentine of these teeth, and was also lower than in both, the early and the late-formed dentine of third molars. As early dentine formation in M1 takes place prior to weaning, this finding indicates a lower dentinal fluoride uptake during the pre-weaning compared to the post-weaning period. This is hypothetically attributed to the action of a partial barrier to fluoride transfer from blood to milk in lactating females and a low bioavailability of fluoride ingested together with milk. Another factor contributing to lower plasma fluoride levels in juveniles compared to adults is the rapid clearance of fluoride from blood plasma in the former due to their intense skeletal growth. The combined action of these mechanisms is considered to explain why in kangaroos from high-fluoride areas, the (early-formed) first molars are not affected by dental fluorosis while the (later-formed) third and fourth molars regularly exhibit marked to severe fluorotic lesions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. The caries-reducing benefit of fluoride-release from dental restorative materials continues after fluoride-release has ended

    NARCIS (Netherlands)

    Shiiya, T.; Mukai, Y.; ten Cate, J.M.; Teranaka, T.

    2012-01-01

    OBJECTIVE: This study tested the hypothesis that the benefit of fluoride-releasing restorative materials continues even after their reserve of fluoride has been depleted. MATERIALS AND METHODS: Pits in perspex blocks simulating cavities were filled with either a fluoride-releasing or a

  19. Effect of fluoride ion on the stability of DNA hairpin

    Science.gov (United States)

    Liu, Chao; Zhai, Weili; Gong, Hongling; Liu, Yanhui; Chen, Hu

    2017-06-01

    Fluoride prevents tooth decay as an additive in oral hygiene products, while high dose intake of fluoride from contaminated drinking water leads to fluorosis. Here we studied the effect of fluoride ion on the stability of DNA double helix using magnetic tweezers. The equilibrium critical force decreases with increasing concentration of fluoride in the range from 1 mM to 100 mM. Our results give the first quantitative measurement of DNA stability in the presence of fluoride ion, which might disturb DNA-related biological processes to cause fluorosis.

  20. Fluorides - mode of action and recommendations for use.

    Science.gov (United States)

    Lussi, Adrian; Hellwig, Elmar; Klimek, Joachim

    2012-01-01

    Various authors have shown that the caries decline in the industrialized countries during recent decades is based on the use of fluorides, of which local fluoride application in the form of fluoridated toothpastes is of primary importance. The caries-protective potential of fluorapatite is quite low; in contrast, dissolved fluorides in the vicinity of enamel are effective both in promoting remineralization and inhibiting demineralization. Considering the fact that the caries decline occurred at the same time that local fluoridation measures became widely used, the conclusion seems justified that regular application of F⁻ can inhibit caries.

  1. Reduced left ventricular cavitary activity ("black hole sign") in thallium-201 SPECT perfusion images of anteroapical transmural myocardial infarction.

    Science.gov (United States)

    Civelek, A C; Shafique, I; Brinker, J A; Durski, K; Weiss, J L; Links, J M; Natarajan, T K; Ozguven, M A; Wagner, H N

    1991-11-01

    Apparently reduced left ventricular (LV) cavitary thallium activity in both planar and tomographic perfusion images has been previously observed by these and other investigators. With single-photon emission computerized tomography, we have clinically noted that this "black hole sign" was associated with an aneurysm in the setting of a transmural anterior or anteroapical perfusion defect. We have now prospectively studied the etiology and predictive value of this sign in 84 consecutive patients with an anterior, anteroapical transmural perfusion defect. Of the 84 patients, 49 had both LV aneurysm (confirmed by contrast ventriculography, echocardiography or gated blood pool studies) and a black hole sign. Only 1 patient with an aneurysm did not have the black hole sign, and 2 without aneurysm did. Thus, it is concluded that this sign is highly accurate in diagnosing LV aneurysm. Because thallium-201 single-photon emission computerized tomography imaging is often performed as one of the first diagnostic tests soon after myocardial infarction, this has important clinical management implications.

  2. The analysis of thallium in geological materials by radiochemical neutron activation and x-ray fluorescence spectrometry: a comparison

    Energy Technology Data Exchange (ETDEWEB)

    McGoldrick, P.J.; Robinson, P. [Tasmania Univ., Sandy Bay, TAS (Australia)

    1993-12-31

    Carrier-based radiochemical neutron activation (RNAA) is a precise and accurate technique for the analysis of Tl in geological materials. For about a decade, until the mid-80s, a procedure modified from Keays et al. (1974) was used at the University of Melbourne to analyse for Tl in a wide variety of geological materials. Samples of powdered rock weighing several hundred milligrams each were irradiated in HIFAR for between 12 hours and 1 week, and subsequently fused with a sodium hydroxide - sodium peroxide mixture and several milligrams of inactive Tl carrier. Following acid digestion of the fusion mixture anion exchange resin was used to separate Tl from the major radioactive rock constituents. The Tl was then stripped from the resin and purified as thallium iodide and a yield measured gravimetrically. Activity from {sup 204}Tl (a {beta}-emitter with a 3 8 year half-life) was measured and Tl determined by reference to pure chemical standards irradiated and processed along with the unkowns. Detection limits for the longer irradiations were about one part per billion. Precision was monitored by repeat analyses of `internal standard` rocks and was estimated to be about five to ten percent (one standard deviation). On the other hand, X-ray fluorescence spectrometry (XRF) was seen as an excellent cost-effective alternative for thallium analysis in geological samples, down to 1 ppm. 6 refs. 1 tab., 1 fig.

  3. Pentoxifylline (Trental) does not inhibit dipyridamole-induced coronary hyperemia: Implications for dipyridamole-thallium-201 myocardial imaging

    Energy Technology Data Exchange (ETDEWEB)

    Brown, K.A.; Slinker, B.K. (Univ. of Vermont College of Medicine, Burlington (USA))

    1990-06-01

    Dipyridamole-thallium-201 imaging is often performed in patients unable to exercise because of peripheral vascular disease. Many of these patients are taking pentoxifylline (Trental), a methylxanthine derivative which may improve intermittent claudication. Whether pentoxifylline inhibits dipyridamole-induced coronary hyperemia like other methylxanthines such as theophylline and should be stopped prior to dipyridamole-thallium-201 imaging is unknown. Therefore, we studied the hyperemic response to dipyridamole in seven open-chest anesthetized dogs after pretreatment with either pentoxifylline (0, 7.5, or 15 mg/kg i.v.) or theophylline (3 mg/kg i.v.). Baseline circumflex coronary blood flows did not differ significantly among treatment groups. Dipyridamole significantly increased coronary blood flow before and after 7.5 or 15 mm/kg i.v. pentoxifylline (p less than 0.002). Neither dose of pentoxifylline significantly decreased the dipyridamole-induced hyperemia, while peak coronary blood flow was significantly lower after theophylline (p less than 0.01). We conclude that pentoxyifylline does not inhibit dipyridamole-induced coronary hyperemia even at high doses.

  4. Fluoride geochemistry of thermal waters in Yellowstone National Park: I. Aqueous fluoride speciation

    Science.gov (United States)

    Deng, Y.; Nordstrom, D.K.; Blaine, McCleskey R.

    2011-01-01

    Thermal water samples from Yellowstone National Park (YNP) have a wide range of pH (1–10), temperature, and high concentrations of fluoride (up to 50 mg/l). High fluoride concentrations are found in waters with field pH higher than 6 (except those in Crater Hills) and temperatures higher than 50 °C based on data from more than 750 water samples covering most thermal areas in YNP from 1975 to 2008. In this study, more than 140 water samples from YNP collected in 2006–2009 were analyzed for free-fluoride activity by ion-selective electrode (ISE) method as an independent check on the reliability of fluoride speciation calculations. The free to total fluoride concentration ratio ranged from 99% at high pH. The wide range in fluoride activity can be explained by strong complexing with H+ and Al3+ under acidic conditions and lack of complexing under basic conditions. Differences between the free-fluoride activities calculated with the WATEQ4F code and those measured by ISE were within 0.3–30% for more than 90% of samples at or above 10−6 molar, providing corroboration for chemical speciation models for a wide range of pH and chemistry of YNP thermal waters. Calculated speciation results show that free fluoride, F−, and major complexes (HF(aq)0">HF(aq)0, AlF2+, AlF2+">AlF2+and AlF30">AlF30) account for more than 95% of total fluoride. Occasionally, some complex species like AlF4-">AlF4-, FeF2+, FeF2+">FeF2+, MgF+ and BF2(OH)2-">BF2(OH)2- may comprise 1–10% when the concentrations of the appropriate components are high. According to the simulation results by PHREEQC and calculated results, the ratio of main fluoride species to total fluoride varies as a function of pH and the concentrations and ratios of F and Al.

  5. 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.

  6. Thallium-201 scintigraphy after dipyridamole infusion with low-level exercise. III Clinical significance and additional diagnostic value of ST segment depression and angina pectoris during the test

    NARCIS (Netherlands)

    G-J. Laarman (GertJan); P.W.J.C. Serruys (Patrick); J.F. Verzijlbergen (Fred); C.A.P.L. Ascoop (Carl); J. Azar

    1990-01-01

    textabstractIntravenous dipyridamole thallium testing is a useful alternative procedure for assessing coronary artery disease (CAD) in patients who are unable to perform maximal exercise tests. Ischaemic ST segment depression and angina pectoris are frequently observed during the test, in particular

  7. Indium-111 antimyosin antibody imaging and thallium-201 imaging. A comparative myocardial scintigraphic study using single-photon emission computed tomography in patients with myocarditis and dilated cardiomyopathy

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Takehiko; Matsumori, Akira; Nohara, Ryuji; Konishi, Junji; Sasayama, Shigetake [Kyoto Univ. (Japan). Faculty of Medicine; Tamaki, Nagara

    1997-10-01

    Indium-111 antimyosin antibody imaging (a tracer of myocardial necrosis) and thallium-201 imaging (a tracer of myocardial perfusion) were compared in patients with myocarditis and dilated cardiomyopathy. The distribution of each tracer and antimyosin/thallium-201 overlapping were evaluated with single-photon emission computed tomography (SPECT). Scintigraphic data were classified into 5 patterns according to the distribution of both images and were compared with histologic findings of endomyocardial biopsy: AM-D, intense and diffuse antimyosin uptake and no perfusion abnormality (active myocarditis); AM-L, localized antimyosin uptake and no perfusion abnormality (active myocarditis); HM, no antimyosin uptake with or without perfusion abnormality (healed myocarditis); DCM-NH, diffuse antimyosin uptake and inhomogeneous thallium-201 uptake (dilated cardiomyopathy); DCM-PD, diffuse or localized antimyosin uptake and myocardial perfusion defect(s) (dilated cardiomyopathy). Patients with dilated-phase hypertrophic cardiomyopathy were frequently found in the DCM-PD group. Taken together, comparative antimyosin/thallium-201 SPECT images are useful for evaluating the activity of myocarditis and ongoing myocardial damage even in areas with no perfusion in patients with dilated cardiomyopathy. (author)

  8. Thallium-201 myocardial scintigraphy in patients with normal coronary arteries and normal left ventriculogram. Comparison with hemodynamic, metabolic and morphologic findings

    Energy Technology Data Exchange (ETDEWEB)

    Loesse, B.; Kuhn, H.; Rafflenbeul, D.; Kroenert, H.; Hort, W.; Feinendegen, L.E.; Loogen, F.

    1980-01-01

    36 consecutive patients with chest pain and/or severe ventricular dysrhythmias, but normal coronary arteries and normal left ventriculogram, underwent thallium-201 myocardial imaging at rest and during exercise. The myocardial scintigram was abnormal in 27 patients (group A) and normal in only 9 patients (group B).

  9. Preconcentration of thallium (I) by single drop microextraction with electrothermal atomic absorption spectroscopy detection using dicyclohexano-18-crown-6 as extractant system.

    Science.gov (United States)

    Chamsaz, Mahmoud; Arbab-Zavar, Mohammad Hossien; Darroudi, Abolfazl; Salehi, Thiery

    2009-08-15

    A simple single drop liquid-phase microextraction (SDME) technique, combined with electrothermal atomic absorption spectroscopy (ETAAS) is developed both to preconcentrate and determine thallium (I) ions in aqueous solutions. The ions were transferred from 10.0 ml of aqueous sample (donor phase) containing 0.5 ml of 1% picric acid as the ion-pair agent into a 3 microl microdrop of nitrobenzene (acceptor phase) containing dicyclohexano-18-crown-6 as the complexing agent. The latter will help to improve the extraction efficiency of the analyte. After the ions have been extracted, the acceptor drop was directly injected into a graphite furnace for thallium (I) determination. Several parameters such as the extracting solvent, extraction time, temperature, concentration of picric acid and crown ether, drop volume and stirring rate were examined. Under the optimized experimental conditions, the detection limit (L.O.D.) was 0.7 ng ml(-1). The relative standard deviation for five replicate analysis of 10 ng ml(-1) of thallium (I) was 5.1%. The calibration curve was linear in the range of 3-22 ng ml(-1). The results for determination of thallium in reference material, spiked tap water and seawater demonstrated the accuracy, recovery and applicability of the presented method. The enrichment factor was 50.

  10. 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.

  11. FLUORIDE CONTENT OF COMMERCIALLY AVAILABLE SOY MILK PRODUCTS IN THAILAND.

    Science.gov (United States)

    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.

  12. [Fluoride emission from different soil minerals at high temperatures].

    Science.gov (United States)

    Wu, W; Xie, Z; Xu, J; Liu, C

    2001-03-01

    The emission characteristics of fluoride pollutants from montmorillonite, kaolinite, vermiculite, geothite and allophane were studied to elucidate the mechanism of fluoride-releasing from soils during brick and tile making at high temperatures from 300 degrees C to 1000 degrees C. The rate of fluoride emission varied with temperature, mineral type, heating time, specific surface area and cations added to minerals. The escape of crystalline water resulting from crystal lattice collapse at a certain high temperature was found to affect the rate of fluoride emission. Calcium compounds could decrease fluoride emission rate from montmorillonite. At 800 degrees C, the rate of fluoride emission from Ca-treated montmorillonite decreased by 59.6% compared to untreated montmorillonite. The order for fluoride-fixing capacity of the 5 calcium compounds at 800 degrees C was as follows: CaCO3 > CaO > Ca3(PO4)2 > Ca(OH)2 > CaSO4.

  13. [The impact of tap water fluoridation on human health].

    Science.gov (United States)

    Romero, Verena; Norris, Frances J; Ríos, Juvenal A; Cortés, Isel; González, Andrea; Gaete, Leonardo; Tchernitchin, Andrei N

    2017-02-01

    The purpose of this review is to describe the osteological, neurological, endocrine and dermatological effects of fluoride ingestion. Additional aims are to evaluate whether the Chilean tap water fluoridation program has had any impact on dental health, and analyze the basis for the Chilean elementary school milk fluoridation program, which is targeted at children living in places where tap water has a fluoride concentration less than 0.3 mg/L, without any artificial fluoridation process. We discuss the finding that both public measures have no direct or remarkable effect on dental health, since topical dental hygiene products are the main and most effective contributors to the prevention of dental decay. We also suggest that the permanent and systematic ingestion of fluorides imposes health risks on the population. Therefore, we recommend reevaluating the national fluoridation program for public tap water and the elementary school milk program.

  14. Prevention of dental caries through the effective use of fluoride

    DEFF Research Database (Denmark)

    Petersen, Poul Erik

    2016-01-01

    , lifestyles, and the existence of preventive oral health programmes. Research conducted in high income countries documents that systematic use of fluoride reduces the burden of dental caries; such research is scarce in low and middle income countries. Objectives: This article reviews the evidence on effective...... use of fluoride, highlights the public health approach to fluoridation, and clarifies how automatic fluoridation contributes to breaking social inequities in dental caries. Data collection: Scientific publications on fluoride administration stored in PubMed/Medline and caries data from the WHO...... databank. Outcome: Dental caries identified from national surveys or country relevant data; extraction of scientific reports is based on their public health relevance. Conclusions: The article outlines the history of fluoridation programmes and describes the sound evidence on automatic fluoridation through...

  15. Compressive strength, surface roughness, fluoride release and recharge of four new fluoride-releasing fissure sealants.

    Science.gov (United States)

    Kavaloglu Cildir, Sule; Sandalli, Nuket

    2007-05-01

    The aim of this study was to investigate the compressive strength and surface roughness of two glass ionomer cements and two resin-based fissure sealants before and after fluoride release and recharge. Twenty-one specimens were prepared and divided into three groups for each material. First group was loaded in compression until failure. Fluoride released was measured from the remaining specimens, and then the second group of seven specimens was loaded at 28th day. The remaining seven specimens were exposed to 0.05% NaF solution and 1.23% APF gel. Fluoride amount was measured, and the last group was loaded at 70th day. Surface roughness measurement of five more disk-shaped specimens from each material was also carried out. After exposure to APF gel, all materials were recharged. At the end of experimental period, it was found that surface roughness increased, whereas compressive strength decreased, over time. In conclusion, fluoride-releasing fissure sealants could act as show, rechargeable fluoride release systems. However, if a fissure sealant exhibited high fluoride release, it had inferior mechanical properties.

  16. Estimated Fluoride Doses from Toothpastes Should be Based on Total Soluble Fluoride

    Directory of Open Access Journals (Sweden)

    Jaime A. Cury

    2013-11-01

    Full Text Available The fluoride dose ingested by young children may be overestimated if based on levels of total fluoride (TF rather than levels of bioavailable fluoride (total soluble fluoride—TSF in toothpaste. The aim of the present study was to compare doses of fluoride intake based on TF and TSF. Fluoride intake in 158 Brazilian children aged three and four years was determined after tooth brushing with their usual toothpaste (either family toothpaste (n = 80 or children’s toothpaste (n = 78. The estimated dose (mg F/day/Kg of body weight of TF or TSF ingested was calculated from the chemical analysis of the toothpastes. Although the ingested dose of TF from the family toothpastes was higher than that from the children’s toothpastes (0.074 ± 0.007 and 0.039 ± 0.003 mg F/day/Kg, respectively; p 0.05. The fluoride dose ingested by children from toothpastes may be overestimated if based on the TF of the product. This finding suggests that the ingested dose should be calculated based on TSF. Dose of TSF ingested by children is similar whether family or children’s toothpaste is used.

  17. Actinide measurements by AMS using fluoride matrices

    Energy Technology Data Exchange (ETDEWEB)

    Cornett, R.J., E-mail: Jack.Cornett@uottawa.ca [André E. Lalonde AMS Laboratory, University of Ottawa, 150 Louis Pasteur, Ottawa, ON K1N 6N5 (Canada); Department of Earth Sciences, University of Ottawa, 150 Louis Pasteur, Ottawa, ON K1N 6N5 (Canada); Kazi, Z.H. [André E. Lalonde AMS Laboratory, University of Ottawa, 150 Louis Pasteur, Ottawa, ON K1N 6N5 (Canada); Department of Earth Sciences, University of Ottawa, 150 Louis Pasteur, Ottawa, ON K1N 6N5 (Canada); Zhao, X.-L. [André E. Lalonde AMS Laboratory, University of Ottawa, 150 Louis Pasteur, Ottawa, ON K1N 6N5 (Canada); Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, ON K1N 6N5 (Canada); Chartrand, M.G. [André E. Lalonde AMS Laboratory, University of Ottawa, 150 Louis Pasteur, Ottawa, ON K1N 6N5 (Canada); Department of Earth Sciences, University of Ottawa, 150 Louis Pasteur, Ottawa, ON K1N 6N5 (Canada); Charles, R.J.; Kieser, W.E. [André E. Lalonde AMS Laboratory, University of Ottawa, 150 Louis Pasteur, Ottawa, ON K1N 6N5 (Canada); Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, ON K1N 6N5 (Canada)

    2015-10-15

    Actinides can be measured by alpha spectroscopy (AS), mass spectroscopy or accelerator mass spectrometry (AMS). We tested a simple method to separate Pu and Am isotopes from the sample matrix using a single extraction chromatography column. The actinides in the column eluent were then measured by AS or AMS using a fluoride target matrix. Pu and Am were coprecipitated with NdF{sub 3}. The strongest AMS beams of Pu and Am were produced when there was a large excess of fluoride donor atoms in the target and the NdF{sub 3} precipitates were diluted about 6–8 fold with PbF{sub 2}. The measured concentrations of {sup 239,240}Pu and {sup 241}Am agreed with the concentrations in standards of known activity and with two IAEA certified reference materials. Measurements of {sup 239,240}Pu and {sup 241}Am made at A.E. Lalonde AMS Laboratory agree, within their statistical uncertainty, with independent measurements made using the IsoTrace AMS system. This work demonstrated that fluoride targets can produce reliable beams of actinide anions and that the measurement of actinides using fluorides agree with published values in certified reference materials.

  18. CORRELATION AMONG FLUORIDE AND METALS IN IRRIGATION ...

    African Journals Online (AJOL)

    Preferred Customer

    emissions from volcanoes and in marine aerosols. The main natural source of inorganic fluorides in soil is the parent rock. Anthropogenic sources of .... mm polyethylene sieve to remove large debris, stones, and pebbles. The part of the sample which passes through the sieve was collected in to the plastic bag and stored for ...

  19. FLUORIDE REMOVAL BY ADSORPTION ON THERMALLY ...

    African Journals Online (AJOL)

    Preferred Customer

    I. M.Sc. Thesis, Addiss Ababa University, Addis Ababa, Ethiopia, 1999. 30. Bulusu, K.R.; Sundaresan, B.B. J. Environ. Eng. 1979, 60, 1. 31. Commis, B.T. Control of Excessive Fluoride Levels for Small Community Water Supplies with Particular Reference to Developing Countries: an interim brief Report, Maidenhead,.

  20. Fluoride treatment in corticosteroid induced osteoporosis.

    OpenAIRE

    Rejou, F; Dumas, R; Belon, C; Meunier, P J; Edouard, C

    1986-01-01

    Severe osteoporosis with multiple vertebral fractures occurred in two girls receiving prolonged high dose corticosteroids for relapsing dermatomyositis. Sodium fluoride, supplemented with calcium and vitamin D, helped control secondary osteoporosis in one case and should be considered as part of the curative treatment of corticoid induced osteoporosis.

  1. CORRELATION AMONG FLUORIDE AND METALS IN IRRIGATION ...

    African Journals Online (AJOL)

    Preferred Customer

    include the following: the industrial production and use of chemicals and phosphate fertilizers. Phosphate fertilizers are the major source of fluoride contamination of agricultural soils [1]. Available quantitative ..... The liquid phase F- concentrations were determined by mixing equal volumes (10 mL) of soil, water samples or ...

  2. Innovative Monitoring of Atmospheric Gaseous Hydrogen Fluoride

    Directory of Open Access Journals (Sweden)

    Stefano Dugheri

    2016-01-01

    Full Text Available Hydrogen fluoride (HF is a basic raw material for a wide variety of industrial products, with a worldwide production capacity of more than three million metric tonnes. A novel method for determining particulate fluoride and gaseous hydrogen fluoride in air is presented herewith. Air was sampled using miniaturised 13 mm Swinnex two-stage filter holders in a medium-flow pumping system and through the absorption of particulate fluoride and HF vapours on cellulose ester filters uncoated or impregnated with sodium carbonate. Furthermore, filter desorption from the holders and the extraction of the pentafluorobenzyl ester derivative based on solid-phase microextraction were performed using an innovative robotic system installed on an xyz autosampler on-line with gas chromatography (GC/mass spectrometry (MS. After generating atmospheres of a known concentration of gaseous HF, we evaluated the agreement between the results of our sampling method and those of the conventional preassembled 37 mm cassette (±8.10%; correlation coefficient: 0.90. In addition, precision (relative standard deviation for n=10, 4.3%, sensitivity (0.2 μg/filter, and linearity (2.0–4000 μg/filter; correlation coefficient: 0.9913 were also evaluated. This procedure combines the efficiency of GC/MS systems with the high throughput (96 samples/day and the quantitative accuracy of pentafluorobenzyl bromide on-sample derivatisation.

  3. Polyvinylidene fluoride film as a capacitor dielectric

    Science.gov (United States)

    Dematos, H. V.

    1981-01-01

    Thin strips of polyvinylidene fluoride film (PVDF) with vacuum deposited electrodes were made into capacitors by conventional winding and fabrication techniques. These devices were used to identify and evaluate the performance characteristics offered by the PVDF in metallized film capacitors. Variations in capacitor parameters with temperature and frequence were evaluated and compared with other dielectric films. Their impact on capacitor applications is discussed.

  4. Fluoride in Dental Biofilm Varies across Intra-Oral Regions.

    Science.gov (United States)

    Staun Larsen, Line; Baelum, Vibeke; Tenuta, Livia Maria Andaló; Richards, Alan; Nyvad, Bente

    2017-01-01

    Information on differences in biofilm fluoride concentration across intra-oral regions may help explain the distribution of caries within the dentition. The aim of this cross-sectional study was to describe the fluoride concentration in saliva and in biofilm fluid and biofilm solids across 6 intra-oral regions. Unstimulated whole saliva was collected from 42 participants and biofilm harvested from the buccal sites in the 4 molar and 2 anterior regions. Samples were collected at least 1 h after use of fluoride dentifrice. No attempt was made to control the participants' food consumption or use of other topical agents. Centrifuged saliva, biofilm fluid, and biofilm solids were analysed for fluoride using a fluoride ion-selective electrode, adapted for microanalysis. Fluoride in biofilm varied across intra-oral regions. The mean biofilm fluid fluoride concentrations across the oral cavity ranged from 11.6 to 16.8 µM, being statistically significantly higher in the upper anterior region than in any other region. In all regions the fluoride concentration in biofilm fluid was higher than in saliva. For biofilm solids the fluoride concentration was highest in the lower anterior region (2,461 μmol/kg) and lowest in the lower molar regions (388 and 406 μmol/kg, respectively). Within biofilm, the solids contained most of the fluoride (81 to >99%). The biofilm fluid fluoride concentration was significantly positively associated with salivary fluoride and only marginally associated with that of biofilm solids. In conclusion, this study has shown pronounced differences in fluoride distribution across intra-oral regions and compartments. This shows that the sampling site is a crucial factor for studies of biofilm fluoride. © 2017 S. Karger AG, Basel.

  5. Fluoride release and uptake abilities of different fissure sealants.

    Science.gov (United States)

    Poggio, Claudio; Andenna, Gianluigi; Ceci, Matteo; Beltrami, Riccardo; Colombo, Marco; Cucca, Lucia

    2016-07-01

    The long-term capability of resin sealants and glass ionomer cements to release fluoride is associated to a reduction in pit and fissure caries. The regular use of fluoride varnishes/toothpastes can result in the absorption of fluoride into the sealant. The objective of the present study was to assess the fluoride release/uptake capacities of different fissure sealants. Three different fissure sealants (Fuji Triage/GC, Fissurit FX/Voco and Grandio Seal/Voco) were examined. Ten discs of each material were prepared. Each disc was incubated with distilled water and then the solution analyzed for diluted for fluoride concentration, using a combination of fluoride electrode (OrionGP 1 S/N 13824, Orion Research Inc, Boston, MA, USA) connected to an expandable ion analyzer (Orion 720A, Orion Research Inc, Boston, MA, USA). Standard curves between 1 and 100 ppm F- were used to calibrate the electrode. Cumulative fluoride release was measured on days 1, 2, 3, 5, 7, 21, 35 and 49, then two different fluoride varnishes/pastes (Profluorid Varnish/Voco, MI Paste Plus/GC), were applied to the sealants tested, and fluoride release (after reuptake) was measured on days 56, 70 and 84. Kruskal Wallis test confirmed significant differences in fluoride release between Fuji Triage/GC and Fissurit FX/Voco and Grandio Seal/Voco from day 1 (P sealants (P sealants except for Fuji Triage/GC (P > 0.05). The GIC-based sealant (Fuji Triage/GC) released significantly more fluoride than the resin sealants tested. The exposure to the fluoridated varnish (Profluorid Varnish) significantly recharged the sealants tested more than the CPP-ACPF toothpaste (MI Paste Plus). Fissure sealants, fluoride release, fluoride uptake, glass ionomer cements.

  6. 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.

  7. Fluoride content of bottled waters available in Northern Greece.

    Science.gov (United States)

    Ahiropoulos, V

    2006-03-01

    The aim of this study was to evaluate the fluoride content of bottled drinking waters commercially available in northern Greece and to report on the accuracy of the labelling of fluoride concentration. Twenty-two randomly selected commercial brands of bottled water were obtained from three supermarkets in Thessaloniki, Greece. Three bottles of each brand were purchased. Following calibration, six tests were conducted on each bottle using a combination fluoride-ion selective electrode (Orion, 96-09-00, MA, USA). The average reading for each brand was estimated and also compared with the fluoride content printed on the label. The mean (+/- SD) fluoride content of the bottled water samples was 0.35 (+/- 1.00) mg F/L with a range from 0.05 to 4.8 mg F/L. Only 18% (N = 4) of brands tested mention the fluoride concentration on the label, and 90% (N = 22) had a tested fluoride between 0.05 and 0.21 mg F/L. Of the remaining two brands, one was found to contain 0.3 mg F/L without having the fluoride concentration indicated on the label, and the other was labelled at 6 mg F/L, whereas the concentration was estimated as 4.8 mg F/L. The use of bottled water may be a significant source of systemic fluoride and therefore be considered as a risk factor for dental fluorosis in young children. This article shows that bottled drinking waters contain differing concentrations of fluoride. The manufacturers' labelling of fluoride concentrations may be inaccurate. When prescribing fluoride supplements, dentists should be aware of the fluoride content of bottled waters used by paediatric patients, especially brands with a concentration higher than 0.3 mg F/L. In view of the wide variation of fluoride concentration in the tested bottled waters, regulatory guidelines for controlling concentration in order to prevent dental fluorosis are recommended.

  8. 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.

  9. Water fluoridation in 40 Brazilian cities: 7 year analysis

    Science.gov (United States)

    MOIMAZ, Suzely Adas Saliba; SALIBA, Nemre Adas; SALIBA, Orlando; SUMIDA, Doris Hissako; de SOUZA, Neila Paula; CHIBA, Fernando Yamamoto; GARBIN, Cléa Adas Saliba

    2013-01-01

    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. PMID:23559106

  10. Retention Improvement in Fluoride Application with Cold Atmospheric Plasma.

    Science.gov (United States)

    Kim, Y M; Lee, H Y; Lee, H J; Kim, J B; Kim, S; Joo, J Y; Kim, G C

    2017-09-01

    This study aimed to apply fluoride formulations to enamel with cold atmospheric plasma (CAP) and analyze the fluoride uptake, retention, and acid resistance quantitatively. Human enamel specimens were divided randomly into 2 groups: group APF1, 1.23% acidulated phosphate fluoride (APF) gel; group APF2, 1.23% APF gel with CAP. Fluoride and CAP were applied to the samples 4 times at 1-wk intervals. The specimens were also stored in artificial saliva for 4 wk to evaluate the retention of fluoride. The fluoride content on the fluoride-treated enamel was measured by an electron probe microanalyzer. To detect the resistance to demineralization, the calcium-to-phosphate ratio of the enamel samples was measured after the application of APF gel with or without CAP, followed by soaking in the demineralization solution. In groups APF1 and APF2, the amount of fluoride detected increased depending on the application frequency, and more fluoride was detected in group APF2 than in group APF1. In the experiment examining the maintenance effect, fluoride was not detected in group APF1, whereas fluoride was detected in group APF2 up to the fourth week. As for the resistance to demineralization, the calcium-to-phosphate ratio of the enamel treated with APF and CAP was higher than that treated with APF alone, and it increased with the frequency of treatment. This study suggests that the combination treatment of CAP and fluoride improves retention of fluoride on the enamel and resistance to demineralization when compared with treatment with fluoride alone.

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

    National Research Council Canada - National Science Library

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

    2011-01-01

    .... 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...

  12. Sorption of sulfuryl fluoride by food commodities.

    Science.gov (United States)

    Sriranjini, Venkata-rao; Rajendran, Somiahnadar

    2008-08-01

    The use of sulfuryl fluoride, a structural fumigant for termite and woodborer control, has recently been expanded to treating stored food commodities and food facilities. There is, however, a lack of data on the sorption of sulfuryl fluoride by food commodities. Knowledge about sorption is important in the context of effective treatment and residues. When sulfuryl fluoride was applied at a dose of 50 g m(-3) to various food commodities (total 68) with 300 g per replicate in 0.75 L gas wash bottles (fumigation chambers) at 25 +/- 1 degrees C, in most cases (81%) the gas concentrations in the free space of the commodities exceeded 50 g m(-3) (range 51-80 g m(-3)) at the end of 24 h exposure. In chambers without the substrate, an average concentration of 49.7 g m(-3) was recorded. About 54% of the commodities showed low-level ( sulfuryl fluoride, 34% showed medium-level (26-50%) sorption and only 12% were highly sorptive (>50%). The latter include white oats (terminal gas concentration 17.8 g m(-3)), some of the decorticated split pulses (24.0-29.3 g m(-3)), chickpea flour (26.3 g m(-3)), dried ginger (29.0 g m(-3)), refined wheat flour (30.3 g m(-3)) and coriander powder (40.5 g m(-3)). In unfumigated control commodities, owing to interfering volatiles, Fumiscope readings in the range 0-13 were noted. Sulfuryl fluoride has the advantage of a low or moderate level of sorption with the majority of the food commodities.

  13. The effect of repeated fluoride recharge and storage media on bond durability of fluoride rechargeable Giomer bonding agent.

    Science.gov (United States)

    Naoum, S; O'Regan, J; Ellakwa, A; Benkhart, R; Swain, M; Martin, E

    2012-06-01

    For a restorative material or adhesive to exhibit caries inhibitive potential through fluoride release, it must be capable of fluoride recharge. The aim of this study was to evaluate the effect of repeated fluoride recharge and different storage media on dentine bond strength durability. Two self-etch adhesive systems (two-step) were evaluated: fluoride-rechargeable Giomer FL-Bond II and non-fluoride-containing UniFil Bond. For each adhesive 32 human dentine specimens were prepared for shear bond strength testing. The specimens were randomly allocated to one of four storage groups: Group 1 - 24-hour water ageing; Group 2 - four-month water ageing; Group 3 - four-month water ageing with weekly fluoride recharge (5000 ppm for 10 minutes); and Group 4 - four-month acid ageing with weekly fluoride recharge. Weekly fluoride recharge over four months ageing did not significantly (p > 0.05) reduce the dentine shear bond strength of FL-Bond II or UniFil Bond. Storage media did not significantly (p > 0.05) affect bond durability. The adhesion between fluoride rechargeable FL-Bond II and dentine maintained durability despite regular fluoride recharge over the four months ageing. Clinicians prescribing the fluoride recharge regime used in the present study to reduce recurrent caries incidence associated with Giomer FL-Bond II restorations can do so without compromising dentine bond strengths. © 2012 Australian Dental Association.

  14. Water fluoridation: a critical review of the physiological effects of ingested fluoride as a public health intervention.

    Science.gov (United States)

    Peckham, Stephen; Awofeso, Niyi

    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.

  15. 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

  16. Synthesis and application of a novel nanostructured ion-imprinted polymer for the preconcentration and determination of thallium(I) ions in water samples

    Energy Technology Data Exchange (ETDEWEB)

    Fayazi, M., E-mail: maryamfayazi64@yahoo.com [Young Researchers and Elite Club, Kerman Branch, Islamic Azad University, Kerman (Iran, Islamic Republic of); Ghanei-Motlagh, M. [Young Researchers and Elite Club, Kerman Branch, Islamic Azad University, Kerman (Iran, Islamic Republic of); Taher, M.A. [Department of Chemistry, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Ghanei-Motlagh, R. [Department of Pathobiology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of); Salavati, M.R. [Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of)

    2016-05-15

    Highlights: • A novel nanostructured thallium(I)-imprinted polymer was evaluated for trace detection of Tl(I). • The prepared sorbent displayed rapid extraction rate, high sensitivity and good reproducibility. • The proposed methodology was applied for quantification of Tl(I) in different water samples. - Abstract: A novel synthesized nanostructured ion-imprinted polymer (IIP) was investigated for the determination of trace amount of thallium(I). For this purpose, the thallium(I) IIP particles were synthesized using methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, methyl-2-[2-(2-2-[2-(methoxycarbonyl) phenoxy] ethoxyethoxy) ethoxy] benzoate as the chelating agent and 2,2-azobisisobutyronitrile (AIBN) as the initiator. The prepared IIP particles were characterized by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR) and thermo gravimetric analysis (TGA). Various experimental factors such as pH, the amount of IIP particles, sorption and desorption time, sample volume, elution condition, and potentially interfering ions systematically examined. Under the optimum conditions, a sensitive response to Tl(I) within a wide concentration range (0.05–18 μg L{sup −1}) was achieved. The limit of detection (LOD, 3S{sub b}/m) was 6.3 ng L{sup −1}. The maximum adsorption capacity of the novel imprinted adsorbent for Tl(I) was calculated to be 18.3 mg g{sup −1}. The relative standard deviation (RSD) for eight replicate detections of 0.1 μg L{sup −1} of thallium(I) was found to be 4.0%. An enrichment factor (EF) of 100 was obtained by this method. The proposed technique was successfully applied to monitoring thallium in different water samples and the certified reference material.

  17. L-Tyrosine immobilized on multiwalled carbon nanotubes: A new substrate for thallium separation and speciation using stabilized temperature platform furnace-electrothermal atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco, Pablo H.; Gil, Raul A. [Departamento de Quimica Analitica, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, P.O. Box 375, 5700 San Luis (Argentina); Instituto de Quimica de San Luis (INQUISAL-CONICET), Chacabuco y Pedernera, CP 5700, San Luis (Argentina); Smichowski, Patricia, E-mail: smichows@cnea.gov.ar [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Rivadavia 1917, CP C1033 AAJ, Ciudad de Buenos Aires (Argentina); Comision Nacional de Energia Atomica, Gerencia Quimica, Av. Gral. Paz 1499, B1650KNA San Martin (Argentina); Polla, Griselda [Comision Nacional de Energia Atomica, Gerencia de Investigacion y Aplicaciones, Av.Gral. Paz 1499, B1650KNA San Martin (Argentina); Martinez, Luis D., E-mail: ldm@unsl.edu.ar [Departamento de Quimica Analitica, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, P.O. Box 375, 5700 San Luis (Argentina); Instituto de Quimica de San Luis (INQUISAL-CONICET), Chacabuco y Pedernera, CP 5700, San Luis (Argentina)

    2009-12-10

    An approach for the separation and determination of inorganic thallium species is described. A new sorbent, L-tyrosine-carbon nanotubes (L-tyr-CNTs), was used and applied to the analysis of tap water samples. At pH 5.0, L-tyr was selective only towards Tl(III), while total thallium was determined directly by stabilized temperature platform furnace-electrothermal atomic absorption spectrometry (STPF-ETAAS). The Tl(III) specie, which was retained by L-tyrosine, was quantitatively eluted from the column with 10% of nitric acid. An on-line breakthrough curve was used to determine the column capacity, which resulted to be 9.00 {mu}mol of Tl(III) g{sup -1} of L-tyr-CNTs with a molar ratio of 0.14 (moles of Tl bound to moles of L-tyr at pH 5). Transient peak areas revealed that Tl stripping from the column occurred instantaneously. Effects of sample flow rate, concentration and flow rate of the eluent, and interfering ions on the recovery of the analyte were systematically investigated. The detection limit for the determination of total thallium (3{sigma}) by STPF-ETAAS was 150 ng L{sup -1}. The detection limit (3{sigma}) for Tl(III) employing the separation system was 3 ng L{sup -1}, with an enrichment factor of 40. The precision of the method expressed as the relative standard deviation (RSD) resulted to be 3.4%. The proposed method was applied to the speciation and determination of inorganic thallium in tap water samples. The found concentrations were in the range of 0.88-0.91 {mu}g L{sup -1} of Tl(III), and 3.69-3.91 {mu}g L{sup -1} of total thallium.

  18. Tracing subducted sediment inputs to the Ryukyu arc-Okinawa Trough system: Evidence from thallium isotopes

    Science.gov (United States)

    Shu, Yunchao; Nielsen, Sune G.; Zeng, Zhigang; Shinjo, Ryuichi; Blusztajn, Jerzy; Wang, Xiaoyuan; Chen, Shuai

    2017-11-01

    Sediments are actively subducted in virtually every arc worldwide. However, quantifying their contributions to arc lavas and thereby establishing budgets of how sediments participate in slab-mantle interaction is challenging. In this contribution we use thallium (Tl) abundances and isotopic compositions of lavas from the Ryukyu arc (including south Kyushu) and its back-arc basin, Okinawa Trough, to investigate the influence of sediments from arc to back-arc. We also present extensive geochemical data for sediments and altered oceanic crust (AOC) outboard of the northern (DSDP Sites 296, 442B, 443 and 444) and central (DSDP Sites 294 and 295) part of the Ryukyu arc. The Tl isotopic compositions of sediments change systematically from lighter outboard of northern Ryukyu arc to heavier outboard of central Ryukyu arc. The feature reflects the dominance of terrigenous material and pelagic sedimentation outboard of the northern and central Ryukyu arc, respectively. Central and northern sections of Ryukyu arc and Okinawa Trough display larger range of Tl isotopic variation than southern section, which is consistent with more pelagic provenance for sediments outboard of central and northern Ryukyu arcs than that of expected sediments outboard of southern Ryukyu arc. Identical Tl, Sr, Nd and Pb isotope variations are found when comparing arc and back arc lavas, which indicates that sediments fluxes also account for the Tl isotopic variations in the Okinawa Trough lavas. Two-end-member mixing models of Tl with Pb, Sr and Nd isotopes require sediment inputs ofsediment end members predict very similar sediment fluxes when using Tl, Sr, Nd and Pb isotopes, which indicates that fractionation of these elements must have happened after mixing between mantle and sediments. This conclusion is corroborated by model calculations of mixing between sediment melts with fractionated Sr/Nd ratios and mantle wedge, which show that no arc lava plot on such mixing lines. Thus bulk sediment

  19. Comparison of arbutamine stress and treadmill exercise thallium-201 SPECT: Hemodynamics, safety profile and diagnostic accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Kiat, H.; Berman, D.S. [Cedars-Sinai Medical Centre, Los Angeles, California, LA (United States)

    1998-02-01

    Full text: Arbutamine (ARB), a new pharmacologic stress agent with enhanced chronotropic property compared to dobutamine, was compared with treadmill (TM) exercise testing (Ex) in a multicenter study using thallium-201 (Tl) SPECT. Of the total of 184 patients who underwent ARB, 69 also had TM stress and quantitative coronary angiography. Fifty-eight patients with a low pretest likelihood of CAD also underwent ARB study for evaluation of test specificity (normalcy rate). Tl scans were scored by a central laboratory using a 20 segment (seg)/scan visual analysis (5 point system: 0=normal, 4-absent uptake). Maximum heart rate (HR) by ARB and Ex was 122 vs 141 bpm (p<0.05). Mean %HR change from baseline was similar (79% vs 82%, respectively, p=ns). Maximum systolic BP for ARB and Ex was 173 vs 175 mmHg, and mean % change from baseline was 24% vs 28% (p=ns). Sensitivity for detecting CAD (270% stenosis) by ARB Tl was 94% and 97% by Ex Tl (p=ns). Stress Tl SPECT segmental agreement for presence of defect between ARB and Ex was 92% (kappa=0.8, p<0.001). Exact segmental stress Tl score (0-4 grading) agreement was 83 % (kappa=0.7, p<0.001). Among 346 segs with stress defects by both ARB and Ex defect reversibility agreement was 86% (kappa=0.7, p<0.001). The normalcy rate for ARB TI-SPECT among patients with a low likelihood of CAD was 90%. Adverse events were mostly mild (tremor: 23%, flushing: 10%, headache: 10%, paraesthesia: 8%, dizziness: 8%, hot flushes: 4%). Arrhythimia of clinical concern occurred in 8% (10/122) of ARB patients who had cardiac catheterisation and in 1.4% (1/69) of patients who had stress Tl. Of all 184 patients with ARB stress, ARB was discontinued due to arrhythmia in 7(5%) and 1 patient had IV Metoprolol for frequent ventricular couplets. Sustained arrhythmias were not observed

  20. Thallium Isotopes Tracking Mn-Oxide Burial - A Proxy for Deoxygenation During Oceanic Anoxic Event 2

    Science.gov (United States)

    Ostrander, C.; Owens, J. D.; Nielsen, S.

    2015-12-01

    Thallium (Tl) is proving to be a useful paleoredox proxy given that the Tl isotope composition of seawater is highly dependent on the magnitude of manganese (Mn) oxide burial in the ocean. In turn, Mn oxides require oxygen at the sediment-water interface to precipitate, linking the Tl isotope cycle to ocean oxygenation. Currently, the marine residence time of Tl is ~20kyrs and the Tl isotope composition of seawater is invariant, which suggests Tl isotopes could be a global tracer of marine Mn-oxide burial. Importantly, recent research suggests sediments deposited under a euxinic water column faithfully record the Tl isotope value of the overlying oxic water column (e.g. Black Sea and Cariaco Basin). Therefore, analysis of organic-rich black shales may prove useful in evaluating the seawater Tl isotope composition of past oceans and, hence, large-scale burial of Mn-oxides and the extent of bottom water ocean oxygenation. A logical test for this proxy is during the well-studied Cenomanian-Turonian boundary event termed Oceanic Anoxic Event 2 (OAE-2) at ~94 Ma. It is known that the global extent of anoxia and euxinia increased during this event, however, to what extent global bottom water deoxygenation occured is unconstrained. If deep water deoxygenation occurred, it would be hypothesized that Mn-oxide precipitation would decrease, resulting in a positive Tl isotope excursion during OAE-2. We have analyzed the Tl isotope composition of organic-rich black shales from Site 1258 of the Ocean Drilling Program (ODP) spanning the period before, during, and after OAE-2. Based on Fe redox proxies, the entire section is euxinic and thus no Mn-oxides are present (i.e. no local redox changes). Before the event, Tl isotope compositions are similar or slightly heavier than modern seawater values. Just prior to the onset of OAE-2, a positive shift occurs and is maintained until recovery, slightly before the termination of the event. The shift to heavier values and subsequent

  1. Geochemical translocation of thallium in the sediments from the North River, China

    Science.gov (United States)

    Liu, J.

    2016-12-01

    Thallium (Tl) is a highly toxic rare heavy metal. As a sulphophile element, it usually occurs in numerous sulphide minerals (such as pyrite, galena, sphlerite). Guangdong north region, known as the hometown of nonferrous metals, has abundant containing Tl mineral resources. Numerous industrial activities, such as mining, smelting, and electroplating are also flourishing. In 2010, a serious Tl pollution in the North River (a major river in the Northern Guangdong Province) shocked the society. The Tl pollution in water appeared to be under control after that incident. But in fact, even if the wastewater discharge of pollution sources has been controlled, the potential risk of heavy metal pollution in the sediments of the North River still exists, for the metals are easy to precipitate and accumulate into sediment from water. So far, Tl pollution in sediments has been studied to a very limited extent. In this paper, we investigated the content and vertical distribution characteristics of Tl and some other related heavy metals in a typical sediment profile from the North River by using inductively coupled plasma mass spectrometry (ICP-MS). Then the Pb isotopic compositions in the sediments were measured by using multi-inductively coupled plasma mass spectrometry (MC-ICP-MS). Several sediments from typical layers were also subjected to sequential extraction procedure for investigating the geochemical fractions of Tl. The risk of Tl and other metal pollution was finally assessed by calculating geo-accumulation indexes (Igeo) and potential ecological risk. The results showed that: (1) Tl concentrations range 1.03 mg/kg to 3.13 mg/kg with a mean of 1.89 mg/kg, three times higher than that in local background soil; (2) Tl content generally increased with depth with some fluctuations and significant correlations were found between Tl and Pb, Zn, Cd, Cu, and Ni; (3) About 46 % to 70 % in sediment cores were resided in the residual fraction; (4) Igeo showed that the studied

  2. 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.

  3. [Fluoride urinary excretion in Mexico City's preschool children].

    Science.gov (United States)

    Juárez-López, María Lilia Adriana; Hernández-Guerrero, Juan Carlos; Jiménez-Farfán, Dolores; Molina-Frechero, Nelly; Murrieta-Pruneda, Francisco; López-Jiménez, Georgina

    2008-01-01

    The assessment of urinary fluoride excretion during dental developing stage has been reported for different countries with community fluoride programs. Also, one of the factors that could influence on retention and excretion of fluoride is the deficient nutrition so the aim of this study was to determine fluoride urinary excretion by a group of preschool children with and without malnutrition. Urinary samples from 24 hours were collected from 60 preschool children selected by convenience from Iztapalapa area of Mexico City, 30 with malnutrition and 30 with standard nutritrional status by weight for age. The samples were analyzed by fluoride especific electrode. Orion 720A. The average concentration of fluoride in urine from preschool children with and without malnutrition were 0.89 +/- 0.4 mg/L and 0.80 +/- 0.3 mg/L, respectively. The mean of 24 hours total fluoride excreted were 367 +/- 150 microg/24 hrs. in malnutrition children and 355 +/- 169 microg/24 hrs. for those with standard nutritional status. There were no differences statistically significant between groups. The urinary fluoride excretion for children with and without malnutrition were in the optimal range of fluoridation for the prevention of caries decay. Malnutrition was no associated with changes on fluoride orine concentration and excretion rates.

  4. Fluoride concentration from dental sealants: a randomized clinical trial.

    Science.gov (United States)

    Campus, G; Carta, G; Cagetti, M G; Bossù, M; Sale, S; Cocco, F; Conti, G; Nardone, M; Sanna, G; Strohmenger, L; Lingström, P

    2013-07-01

    A randomized clinical trial was performed in schoolchildren (6-7 yrs) to evaluate fluoride concentration in interproximal fluid after the placement of 3 different sealants. The sample consisted of 2,776 children randomly divided: 926 in the high-viscosity Glass-ionomer Cement group (GIC group), 923 in the fluoride Resin-based group (fluoride-RB group), and 927 in the no-fluoride Resin-based group (RB group). In total, 2,640 children completed the trial. Sealants were applied following manufacturer's instructions. Interproximal fluid samples were collected at baseline and 2, 7, and 21 days after application of sealants, by insertion of a standardized paperpoint into the interproximal mesial space of the sealed tooth for 15 seconds. Fluoride concentration was evaluated by means of a fluoride ion-selective electrode. At 2 days after sealant application, fluoride concentration was significantly higher in GIC and fluoride-RB groups compared with that in the RB group (p sealants increased the fluoride concentrations in interproximal fluid more than did a Resin-based sealant containing fluoride.

  5. A comparative study of fluoride release from two different sealants.

    Science.gov (United States)

    Ananda, Shimoga-Raju; Mythri, Halappa

    2014-12-01

    The introduction of fluoride releasing sealants and glass ionomer cements as fissure sealants adds another dimension to prevention of pit and fissure caries. The ability of resin sealants and glass ionomer cements to release fluoride on a long term basis to the sealed enamel and the adjacent unsealed pit and fissure and cuspal incline enamel may allow for further reduction in pit and fissure caries experience for children. Hence, the study was conducted to compare the amount of fluoride release in the plaque after placing fluoride releasing pit and fissure sealants and glass ionomer fissure sealants used in Atraumatic Restorative Treatment (ART) approach. To compare the fluoride release of both the materials at the different time intervals. A total of 60 school going children were included in this study. Before application of the sealants, baseline plaque fluoride levels were estimated from all the study subjects. After application of sealants again the same was estimated at an interval of 24 hour, 9 days, 2 weeks and 4 weeks. The peak plaque fluoride levels were achieved at 24 hours after application of fissure sealants in all the groups. Within the limitation of the study, the present study indicated that fluoride releasing fissure sealants may act as a source of fluoride in plaque which will help in preventing pit and fissure and smooth surface caries in the tooth sealed with fissure sealants. Key words:Plaque fluoride, pit and fissures sealants, dental caries.

  6. Caries prevention through the fluoridation of milk. A review.

    Science.gov (United States)

    Bánóczy, Jolán; Rugg-Gunn, Andrew J

    2007-10-01

    The aim of this review is to give an overview of 50 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 from the early 1980s onwards. Numerous peer-reviewed publications in international journals showed clearly the bioavailability of fluoride in milk, and increased concentrations of fluoride in saliva, dental plaque, dental enamel and dentine, and urine, after consumption of fluoridated 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 programs. These evaluations showed clearly that the optimal daily intake of fluoride in milk is effective in preventing dental caries. At present, milk fluoridation programs are running continuously in about ten countries of the world. 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 program. The program should aim to provide fluoridated milk for at least 200 days per year and should commence before the children are 4 years of age.

  7. 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.

  8. Effects of long term exposure to hydrogen fluoride on grapevines

    Energy Technology Data Exchange (ETDEWEB)

    Murray, F.

    1984-01-01

    Grapevines Vitis vinifera L. Shiraz were exposed to hydrogen fluoride in open-top chambers for 189 days at mean atmospheric fluoride concentrations of 0.27, 0.17 or 0.07 ..mu..g HFm/sup -3/. Grapevines growing under ambient conditions outside the chambers were exposed to a mean atmospheric fluoride concentration of 0.08 ..mu..g HFm/sup -3/. The maximum leaf fluoride concentrations associated with these treatments were 62, 27, 9 and 15 ..mu..g Fg/sup -1/, respectively. Foliar necrosis was first observed on grapevines exposed to 0.27 and 0.17 ..mu..g HFm/sup -3/ after 83 and 99 days, respectively. Exposure to fluoride increased the fluoride content of berries and peduncles, and reduced leaf chlorophyll a and total chlorophyll concentration at both mid-season and harvest. Exposure to 0.17 ..mu..g HF m/sup -3/ was associated with higher total acid content of grapes than other treatments. Fluoride had no significant effect on bunch weight, number of bunches, grape yield, grape water or potential alcohol content, leaf chlorophyll b or leaf protein concentration. The high accumulation of fluoride in peduncles, but low fluoride accumulation in berries, suggests that the peduncle acts to block the translocation of fluoride from sites of uptake to the fruit. 42 references, 1 figure, 5 tables.

  9. [Fluoridation of drinking water, why is it needed?].

    Science.gov (United States)

    Zusman, S P; Natapov, L; Ramon, T

    2004-01-01

    Dental caries is a widespread disease. It causes irreversible damage, pain and considerable expense. Fluoride is the only known substance that raises the tooth's resistance to acid attack. Natural drinking waters contain fluoride at different concentration. The most effective method of fluoride administration to the community level is by adjustng the fluoride concentration in the drinking water to about 1 part per million. To describe the mode of action of fluoride, methods of administration and to describe water fluoridation, advantages and disadvantages. Fluoridation of drinking water started in 1945 in the world and in 1981 in Israel. Today more then 300 million people in some 60 countries enjoy the defending effect of fluoride in drinking water. This is the most effective method for decreasing incidence of caries, as well as being cost effective. Over the years there were many attempts to 'blame' fluoridation with negative side effects to human health. Till today, none of the allegations passed scientific scrutiny. There is overwhelming scientific support for the Regulations that oblige the Water supplier to adjust fluoride levels to 1 ppm in every town or municipality with more then 5,000 inhabitants.

  10. Arsenic from community water fluoridation: quantifying the effect.

    Science.gov (United States)

    Peterson, Emily; Shapiro, Howard; Li, Ye; Minnery, John G; Copes, Ray

    2016-04-01

    Community water fluoridation is a WHO recommended strategy to prevent dental carries. One debated concern is that hydrofluorosilicic acid, used to fluoridate water, contains arsenic and poses a health risk. This study was undertaken to determine if fluoridation contributes to arsenic in drinking water, to estimate the amount of additional arsenic associated with fluoridation, and compare this to the National Sanitation Foundation/American National Standards Institute (NSF/ANSI) standard and estimates from other researchers. Using surveillance data from Ontario drinking water systems, mixed effects linear regression was performed to examine the effect of fluoridation status on the difference in arsenic concentration between raw water and treated water samples. On average, drinking water treatment was found to reduce arsenic levels in water in both fluoridated and non-fluoridated systems by 0.2 μg/L. However, fluoridated systems were associated with an additional 0.078 μg/L (95% CI 0.021, 0.136) of arsenic in water when compared to non-fluoridated systems (P = 0.008) while controlling for raw water arsenic concentrations, types of treatment processes, and source water type. Our estimate is consistent with concentrations expected from other research and is less than 10% of the NSF/ANSI standard of 1 μg/L arsenic in water. This study provides further information to inform decision-making regarding community water fluoridation.

  11. Knowledge, attitude and use of fluorides among dentists in Texas.

    Science.gov (United States)

    Bansal, Ritu; Bolin, Kenneth A; Abdellatif, Hoda M; Shulman, Jay D

    2012-05-01

    The centers for disease control and prevention (CDC) recommendations on fluoride use were published in 2001. This study examines how this information has diffused to practicing dentists and the level of fluoride knowledge and use among Texas dentists. A questionnaire was sent to dentists who self-identified as being in pediatric (343), dental public health (72), and general practices (980); a 12% sample of registered dentists in Texas. Response rate was 42.9%. About 90% of surveyed dentists reported using fluorides routinely. Only 18.8% reported fluoride varnish as the topical fluoride most often used. About 57% incorrectly identified primary effect of fluoride. 'Makes enamel stronger while tooth is developing prior to eruption' was the most commonly cited wrong answer (44%). Only 5% identified that posteruptive effect exceeds any preeruptive effect. Despite the evidence for fluoride varnish preventing and controlling dental caries being Grade I, its use is still uncommon. Dentists are expected to be knowledgeable about products they use, but this study reflects lack of understanding about fluoride's predominant mode of action. More accurate understanding enables dentists to make informed and appropriate judgment on treatment options and effective use of fluoride based on risk assessment of dental caries. Lack of knowledge of, or failure of adherence to evidence based guidelines in caries prevention by use of appropriate fluoride regimens may adversely affect caries incidence in the population.

  12. Effects of different kinds of fluorides on enolase and ATPase activity of a fluoride-sensitive and fluoride-resistant Streptococcus mutans strain.

    Science.gov (United States)

    van Loveren, C; Hoogenkamp, M A; Deng, D M; ten Cate, J M

    2008-01-01

    Enolase and ATPase are sensitive to fluoride. It is unclear whether this sensitivity differs for F-sensitive and F-resistant cells or for different types of fluoride. Permeabilized cells of the fluoride-sensitive strain Streptococcus mutans C180-2 and its fluoride-resistant mutant strain C180-2 FR were preincubated at pH 7 or 4 with NaF, the amine fluorides Olaflur and Dectaflur and amine chloride controls. After preincubations, enolase and ATPase activities of the cells were assessed. Enolase activity was more inhibited after preincubation at pH 7 with NaF than with Olaflur. Amine chloride stimulated, although not with statistical significance, the enolase activity of both strains. After preincubation at pH 4 the enolases were strongly inactivated, but the fluoride-resistant strain's enolase to a lesser extent. The results suggested that amine acts to protect enolase activity against the detrimental low pH effect. Gene sequencing showed that the enolase genes of the fluoride-resistant and fluoride-sensitive strain were identical. ATPase activity was not reduced after NaF preincubation at either pH 7 or pH 4. The amine fluorides and their chloride controls in the preincubation mixture reduced the ATPase activity significantly at both pH values. In conclusion, our results showed that preincubation with amine fluoride did not inhibit enolase activity more effectively than NaF. The amine part of the molecule may protect enolase activity against preincubations at low pH. ATPase activity was not inhibited by NaF preincubation but was significantly inhibited after preincubation with amine fluorides and amine chlorides. (c) 2008 S. Karger AG, Basel.

  13. Parabens do not increase fluoride uptake by dental enamel

    Directory of Open Access Journals (Sweden)

    Vanessa Silva Tramontino

    2010-04-01

    Full Text Available Objective: To evaluate whether methylparaben and propylparaben, which present a similar chemical structure, increase fluoride uptake by demineralized dental enamel when present in buffered solutions. Methods: The study comprised an in vitro experiment using blocks of bovine dental enamel with artificial carious lesions. Enamel blocks were exposed to the following treatment (n=12: fluoride solution (200 ppm fluoride - control; solution containing fluoride and 13 mM methylparaben; solution containing fluoride and 13 mM propylparaben in 35% propylene glycol; solution containing fluoride in 35% propylene glycol. All solutions were buffered (0.01 M cacodilate and the pH was adjusted to 6.27. The blocks were exposed to the treatment solutions in the proportion of 2 ml per mm2 of exposed enamel area and fluoride formed was estimated after removing an enamel layer by acid etching. Fluoride extracted was determined by ion specific electrode and the amount of enamel removed was estimated by phosphorus analysis. ANOVA followed by Tukey’s test were used for statistical analysis, with significance level at 5%. Results: The dental blocks of treatment groups containing both parabens and the control group presented similar fluoride concentration in enamel and no statistical difference was observed among them (p>0.05. The dental blocks of treatment group containing fluoride and propylene glycol showed the lowest value of fluoride present in enamel, which was significantly different from the control and fluoride and methylparaben groups (p<0.05. Conclusion: Methyl and propylparaben in a buffered solution do not enhance fluoride uptake by demineralized dental enamel.

  14. Source and distribution of sedimentary thallium in the Bohai Sea: Implications for hydrodynamic forces and anthropogenic impact

    Science.gov (United States)

    Hu, Ningjing; Liu, Jihua; Shi, Xuefa

    2015-04-01

    Source and distribution of sedimentary thallium in the Bohai Sea: Implications for hydrodynamic forces and anthropogenic impact Hu Ningjing, Liu Jihua, Shi Xuefa First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China Thallium (Tl), a non-essential and highly toxic trace metal, is listed as priority toxic pollutant by the United States Environmental Protection Agency (USEPA) (Keith and Telliard, 1979). However, its geochemical cycling in aquatic environment has received far less attention than that of many other trace metals. This has been attributed to relatively little commercial interest in Tl and, until recently, problems inherent in its detection at environmental concentrations (Meeravali and Jiang, 2008). In this study, we investigated the sources, distribution and fate of Tl in surface sediments of the Bohai Sea (BS), China, based on the datasets of total Tl and chemical speciation of Tl of 408 surface sediment samples in the total entire BS. The enrichment factors and chemical speciation of Tl indicated that Tl in BS was dominated by natural Tl, although anthropogenic Tl contamination was observed in the Liuguhe River mouth; the mud deposits are the sinks of Tl and the regional currents and tide systems play a key role on the accumulation of Tl in BS. The distribution of Tl consistent with that of MnO and Fe2O3 as well as the level of Fe-Mn fraction is relatively high, indicating MnO and Fe2O3 influence the geochemical behaviors of Tl in the BS. Although the positive correlation between Tl and TOC is observed for the samples in the BS, however, level of Tl in oxidizable faction could be neglected, suggesting TOC might not be a major factor affecting the concentration of Tl in BS. The low proportion of Tl in the non-residual fraction dominated by the Fe-Mn oxides suggested that the labile Tl was controlled by the Fe-Mn oxides and Tl has a low bioavailability and a minor potential threat to biota in BS. Acknowledgements: this work

  15. Fluoride intake in children living in a high-fluoride area in Ethiopia - intake through beverages.

    Science.gov (United States)

    Malde, M K; Zerihun, L; Julshamn, K; Bjorvatn, K

    2003-01-01

    The present study was conducted in Wonji Shoa, a sugar estate in the Ethiopian Rift Valley. Drinking water in the area is provided either by the Awash River or by high-fluoride ground water wells. Defluoridation plants have been installed, but are not in regular use, and fluorosis, dental as well as skeletal, is endemic. The aim of this study was to assess daily fluoride intake from drinking water and beverages in children from neighbouring villages with varying fluoride concentration in the drinking water. Thirty families were selected from two of the plantation villages (A and K). The criterion for being included in the project was the presence in the household of at least one child, fully weaned and below the age of 5 years. For sampling of beverages, the duplicate portion technique was used. The fluoride concentration in the beverage samples was determined using standard methods, using a fluoride ion-selective electrode. Ten of the selected households in Village A fetched water from the Awash River (1.8 mg F-/L) while five relied upon water from a local well (2.1 mg F-/L). All 15 households in Village K used water from a local well with fluoride concentration of 14.4 mg/L. The mean daily fluoride intake from drinking water and beverages during the four days, varied from 1.2 to 1.5 mg and 5.9 to 8.8 mg in Village A and K, respectively. Low variety in types of beverages consumed was reported both during the study period and through the questionnaire. Only local water was used for beverage preparation. Children who consumed milk had a reduced fluoride intake. Tea, which was part of the children's diet, was not found to be a main source of fluoride. A2n effective defluoridation of the drinking water or a change of water source would seem to be the only options for avoidance of dental and possibly skeletal fluorosis.

  16. 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

  17. Analysis of differentially expressed genes between fluoride-sensitive and fluoride-endurable individuals in midgut of silkworm, Bombyx mori.

    Science.gov (United States)

    Qian, Heying; Li, Gang; He, Qingling; Zhang, Huaguang; Xu, Anying

    2016-08-15

    Fluoride tolerance is an economically important trait of silkworm. Near-isogenic lines (NILs) of the dominant endurance to fluoride (Def) gene in Bombyx mori has been constructed before. Here, we analyzed the gene expression profiles of midgut of fluoride-sensitive and fluoride-endurable individuals of Def NILs by using high-throughput Illumina sequencing technology and bioinformatics tools, and identified differentially expressed genes between these individuals. A total of 3,612,399 and 3,567,631 clean tags for the libraries of fluoride-endurable and fluoride-sensitive individuals were obtained, which corresponded to 32,933 and 43,976 distinct clean tags, respectively. Analysis of differentially expressed genes indicates that 241 genes are differentially expressed between the two libraries. Among the 241 genes, 30 are up-regulated and 211 are down-regulated in fluoride-endurable individuals. Pathway enrichment analysis demonstrates that genes related to ribosomes, pancreatic secretion, steroid biosynthesis, glutathione metabolism, steroid biosynthesis, and glycerolipid metabolism are down-regulated in fluoride-endurable individuals. qRT-PCR was conducted to confirm the results of the DGE. The present study analyzed differential expression of related genes and tried to find out whether the crucial genes were related to fluoride detoxification which might elucidate fluoride effect and provide a new way in the fluorosis research. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Effects of tannin-fluoride and milk-fluoride mixture on human enamel erosion from inappropriately chlorinated pool water.

    Science.gov (United States)

    Boonviriya, Sumalee; Tannukit, Sissada; Jitpukdeebodintra, Suwanna

    2017-01-01

    This in vitro study aimed to investigate the efficacy of tannin-fluoride and milk-fluoride mixtures on human enamel erosion after exposure to inappropriately chlorinated pool water. Enamel specimens were immersed in swimming pool water (pH 2.7) for 30 min and in each test reagent for 4 min once a day for 60 consecutive days (group I: control, group II: tannin-fluoride, group III: milk-fluoride, group IV: tannin-fluoride before and milk-fluoride after erosive challenge, and group V: milk containing tannin-fluoride before and after erosive exposure). Surface microhardness was assessed on days 0, 30, and 60. Scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) were performed after treatment of samples for 60 days. Surface microhardness of experimental groups was ranked as follows: group III > group IV-group V > group II > group I (P EPMA profiles showed decrease of phosphorus and increase of fluoride content in groups II and IV. In conclusion, we demonstrated that treatment with fluoridated milk with or without tannin-fluoride has protective effects against enamel erosion caused by low-pH swimming pool water.

  19. 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.

  20. Fluoridation and tooth wear in Irish adults.

    LENUS (Irish Health Repository)

    Burke, F M

    2010-10-01

    The aim of this study was to determine the prevalence of tooth wear in adults in Ireland and its relationship with water fluoridation. The National Survey of Adult Oral Health was conducted in 2000\\/2001. Tooth wear was determined using a partial mouth examination assessing the upper and lower anterior teeth. A total of 2456 subjects were examined. In this survey, increasing levels and severity of tooth wear were associated with ageing. Men were more affected by tooth wear and were more likely to be affected by severe tooth wear than women. It was found that age, and gender were significant predictors of tooth wear (P < 0.01). Overall, there was no significant relationship between fluoridation and tooth wear in this study.

  1. Revisiting the thermochemistry of chlorine fluorides.

    Science.gov (United States)

    Sánchez, Hernán R

    2017-08-15

    In this work, accurate calculations of standard enthalpies of formation of chlorine fluorides (ClFn, n = 1-7; Cl2 F and Cl3 F2 ) were performed through the isodesmic reactions scheme. It is argued that, for many chlorine fluorides, the gold standard method of quantum chemistry (CCSD(T)) is not capable to predict enthalpy values nearing chemical accuracy if atomization scheme is used. This is underpinned by a thorough analysis of total atomization energy results and the inspection of multireference features of these compounds. Other thermodynamic quantities were also calculated at different temperatures. To complement the energetic description, elimination curves were studied through density functional theory as a computationally affordable alternative to highly correlated wave function-based methods. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  2. Fluoride in dental biofilm and saliva

    DEFF Research Database (Denmark)

    Larsen, Line Staun

    Dette ph.d.-projekt bidrager med ny viden om fordelingen af fluorid i dental biofilm og saliva. For at udforske koncentrationen af fluorid i naturlig (in vivo) biofilmvæske, biofilmsediment og i saliva, blev der udført to meget forskellige kliniske studier. Resultaterne fra tværsnitsstudiet (Studie...... mellem fluoridkoncentrationerne i biofilmsediment og fordeling af caries mellem regioner. Forskere anbefales at være opmærksomme på de intra-orale forskelle i fluoridkoncentrationer mellem regioner samt sikre balancering af effekten af region, når der indsamles dental biofilm til fluoridanalyse. I det...... I), hos en stor gruppe mennesker (n=42) der konsulterede en tandklinik for behandling, bekræfter tidligere viden, at der findes en naturlig biologisk variation i fluoridkoncentrationerne i biofilm fra forskellige intra-orale regioner samt mellem biofilmvæske, biofilmsediment og saliva...

  3. Revisiting the thermochemistry of chlorine fluorides

    CERN Document Server

    Sánchez, H R

    2016-01-01

    In this work, accurate calculations of standard enthalpies of formation of chlorine fluorides (ClF$_n$, n=1--7; Cl$_2$F and Cl$_3$F$_2$) were performed through the isodesmic reactions scheme. It is argued that, for many chlorine fluorides, the gold standard method of quantum chemistry (CCSD(T)) is not capable to predict enthalpy values nearing chemical accuracy if atomization scheme is used. This is underpinned by a thorough analysis of total atomization energy results and the inspection of multireference features of these compounds. Other thermodynamic quantities were also calculated at different temperatures. In order to complement the energetic description, elimination curves were studied through density functional theory as a computationally affordable alternative to highly correlated wave function-based methods.

  4. Fluoride and the caries lesion: interactions and mechanism of action.

    Science.gov (United States)

    Robinson, C

    2009-09-01

    To review the mechanisms of action of fluoride (F). Narrative review of the literature. Fluoride can reduce tooth mineral solubility by exchanging for hydroxyl groups and reducing carbonate content. Thus its presence in solution facilitates mineral precipitation or reprecipitation by lowering solubility products of precipitating calcium phosphates. While sound enamel tends to lose fluoride with age, it accumulates at stagnation sites where caries lesions develop indicating this as a site of action. Fluoride in the lesion will encourage remineralisation [Robinson et al., 2000] such that penetration of the lesion by fluoride is pivotal. Access from plaque, however, is limited due to restricted penetration. Maintaining a very thin plaque layer is thus important in delivering fluoride to the lesion.

  5. [Problems of fluoride dosing to infants for dental fluorosis prevention].

    Science.gov (United States)

    Davydov, B N; Borinskaia, E Iu; Kushnir, S M; Borinskiĭ, Iu N; Beliaev, V V

    2011-01-01

    Fluoride content in drinking water, breast milk, cow milk, additional food for newborns prepared with water containing different amount of fluoride was determined. Fluoride excretion in urine since the first days of birth and up to 4 months of postnatal development was investigated in breast and artificially fed infants. When a neonate was fed with breast milk, fluoride was received in the amount no more than 20 mkg/day. The additional food contained fluoride which water mainly had. Water with high level of fluorine increased its content in the additional food up to the values not comparable to those in breast milk that presented danger of dental fluorosis development. Data on fluorine content in drinking water were absolutely necessary to calculate daily fluorides consumption by infants and to prevent dental fluorosis.

  6. Perspectives in the effective use of fluoride in Asia

    DEFF Research Database (Denmark)

    Petersen, P E; Phantumvanit, P

    2012-01-01

    and evaluation of fluoride toothpastes and rinses and, to a lesser extent, to alternatives to water fluoridation, such as salt and milk fluoridation. Most recently, efforts have been made to summarize this extensive database through systematic reviews of fluoride administration (McDonagh et al., 2000; Marinho et...... services, in particular, exposure to disease prevention programs (Petersen, 2003, 2008a). Benefits of fluoride for caries prevention have been substantiated in many countries (Petersen and Lennon, 2004; Jones et al., 2005). In the second half of the 20th century, this focus shifted to the development...... al., 2003; Australian Government, 2007). The Asian workshop held in Phan-Nga, Thailand, during March 22-24, 2011, aimed to discuss current information on fluoride and dental caries, as well as to try identifying barriers and opportunities that countries of Asia may have for implementing such programs...

  7. Fractionation and Mobility of Thallium in Volcanic Ashes after Eruption of Eyjafjallajökull (2010) in Iceland.

    Science.gov (United States)

    Karbowska, Bozena; Zembrzuski, Wlodzimierz

    2016-07-01

    Volcanic ash contains thallium (Tl), which is highly toxic to the biosphere. The aim of this study was to determine the Tl concentration in fractions of volcanic ash samples originating from the Eyjafjallajökull volcano. A sequential extraction scheme allowed for a study of element migration in the environment. Differential pulse anodic stripping voltammetry using a flow measuring system was selected as the analytical method to determine Tl content. The highest average content of Tl in volcanic ash was determined in the fraction entrapped in the aluminosilicate matrix (0.329 µg g(-1)), followed by the oxidizable fraction (0.173 µg g(-1)). The lowest content of Tl was found in the water soluble fraction (0.001 µg g(-1)); however, this fraction is important due to the fact that Tl redistribution among all the fractions occurs through the aqueous phase.

  8. Health protection: Fluoridation and dental health.

    OpenAIRE

    1983-01-01

    Tooth decay, which affects 95 percent of Americans, is our most common health problem, costing an estimated +2 billion yearly for treatment. By the time children reach 17 years of age, 94 percent have experienced caries and 36 percent have lost one or more permanent teeth due to caries. Dental disease prevention embodies the spectrum of many activities from the fluoridation of community and school water supplies to the dental health education of the child and adult. At this stage of our knowl...

  9. Effect of fluoride toothpastes on enamel demineralization

    Directory of Open Access Journals (Sweden)

    Gintner Zeno

    2006-06-01

    Full Text Available Abstract Background It was the aim of this study to investigate the effect of four different toothpastes with differing fluoride compounds on enamel remineralization. Methods A 3 × 3 mm window on the enamel surface of 90 human premolars was demineralized in a hydroxyethylcellulose solution at pH 4.8. The teeth were divided into 6 groups and the lower half of the window was covered with varnish serving as control. The teeth were immersed in a toothpaste slurry containing: placebo tooth paste (group 1; remineralization solution (group 2; Elmex Anticaries (group 3; Elmex Sensitive (group 4; Blend-a-med Complete (group 5 and Colgate GRF (group 6. Ten teeth of each group were used for the determination of the F- content in the superficial enamel layer and acid solubility of enamel expressed in soluble phosphorus. Of 6 teeth of each group serial sections were cut and investigated with polarization light microscopy (PLM and quantitative energy dispersive X-ray analysis (EDX. Results The PLM results showed an increased remineralization of the lesion body in the Elmex Anticaries, Elmex Sensitive and Colgate GRF group but not in the Blend-a-med group. A statistically significant higher Ca content was found in the Elmex Anticaries group. The fluoride content in the superficial enamel layer was significantly increased in both Elmex groups and the Blend-a-med group. Phosphorus solubility was significantly decreased in both Elmex groups and the Blend-a-med group. Conclusion It can be concluded that amine fluoride compounds in toothpastes result in a clearly marked remineralization of caries like enamel lesions followed by sodium fluoride and sodium monofluorophosphate formulations.

  10. Effective use of fluorides for the prevention of dental caries in the 21st century

    DEFF Research Database (Denmark)

    Petersen, Poul Erik; Lennon, Michael A

    2004-01-01

    , due to changing living conditions and dietary habits, and inadequate exposure to fluorides. Research on the oral health effects of fluoride started around 100 years ago; the focus has been on the link between water and fluorides and dental caries and fluorosis, topical fluoride applications, fluoride...... toothpastes, and salt and milk fluoridation. Most recently, efforts have been made to summarize the extensive database through systematic reviews. Such reviews concluded that water fluoridation and use of fluoride toothpastes and mouthrinses significantly reduce the prevalence of dental caries. WHO recommends...... for public health that every effort must be made to develop affordable fluoridated toothpastes for use in developing countries. Water fluoridation, where technically feasible and culturally acceptable, has substantial advantages in public health; alternatively, fluoridation of salt and milk fluoridation...

  11. Analysis of fluoride concentration in commercial bottled waters

    OpenAIRE

    BIZERRIL,Davi Oliveira; ALMEIDA, Janaína Rocha de Sousa; SALDANHA, Kátia de Góis Holanda; CABRAL FILHO,Ronaldo Emilio; Almeida, Maria Eneide Leitão de

    2015-01-01

    Objective: Evaluate fluoride concentration in 500ml commercial brands of bottled water and compare it to the amount printed on the label. Methods: A descriptive, cross-sectional epidemiological study was conducted. Samples of nine different commercial brands of 500ml bottled water were collected at authorized distribution points in the city of Fortaleza, CE, Brazil, in 2013. Fluoride concentration was determined in duplicate using a fluoride ion-selective electrode. The results were obtain...

  12. 40 CFR 60.202 - Standard for fluorides.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for fluorides. 60.202 Section... Industry: Wet-Process Phosphoric Acid Plants § 60.202 Standard for fluorides. (a) On and after the date on... facility any gases which contain total fluorides in excess of 10.0 g/Mg of equivalent P2O5 feed (0.020 lb...

  13. 40 CFR 60.192 - Standard for fluorides.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for fluorides. 60.192 Section... Plants § 60.192 Standard for fluorides. (a) On and after the date on which the initial performance test... total fluorides, as measured according to § 60.195, in excess of: (1) 1.0 kg/Mg (2.0 lb/ton) of aluminum...

  14. Combinatorial Effects of Arginine and Fluoride on Oral Bacteria

    OpenAIRE

    Zheng, X.; Cheng, X.; Wang, L.; Qiu, W.; Wang, S.; Zhou, Y.; Li, M.; Li, Y.; Cheng, L.; Li, J.; Zhou, X.; Xu, X.

    2015-01-01

    Dental caries is closely associated with the microbial disequilibrium between acidogenic/aciduric pathogens and alkali-generating commensal residents within the dental plaque. Fluoride is a widely used anticaries agent, which promotes tooth hard-tissue remineralization and suppresses bacterial activities. Recent clinical trials have shown that oral hygiene products containing both fluoride and arginine possess a greater anticaries effect compared with those containing fluoride alone, indicati...

  15. Biological effects data: Fluoride and sulfur dioxide

    Energy Technology Data Exchange (ETDEWEB)

    McMechan, K.J. (ed.); Holton, R.L.; Ulbricht, R.J.; Morgan , J.B.

    1975-04-01

    The Alumax Pacific Aluminum Corporation has proposed construction of an aluminum reduction facility near Youngs Bay at Warrenton, Oregon. This report comprises one part of the final report to Alumax on a research project entitled, Physical, Chemical and Biological Studies of Youngs Bay.'' It presents data pertaining to the potential biological effects of fluoride and sulfur dioxide, two potentially hazardous plant-stack emissions, on selected aquatic species of the area. Companion volumes provide a description of the physical characteristics the geochemistry, and the aquatic animals present in Youngs Bay and adjacent ecosystems. An introductory volume provides general information and maps of the area, and summarizes the conclusions of all four studies. The data from the two phases of the experimental program are included in this report: lethal studies on the effects of selected levels of fluoride and sulfur dioxide on the survival rate of eleven Youngs Bay faunal species from four phyla, and sublethal studies on the effects of fluoride and sulfur dioxide on the rate of primary production of phytoplankton. 44 refs., 18 figs., 38 tabs.

  16. Formulation and characterization of antibacterial fluoride-releasing sealants.

    Science.gov (United States)

    Fan, Yuwei; Townsend, Janice; Wang, Yapin; Lee, Eun Chee; Evans, Katie; Hender, Erica; Hagan, Joseph L; Xu, Xiaoming

    2013-01-01

    The purpose of this study was to formulate and characterize experimental antibacterial fluoride-releasing sealants and compare them with commercial sealants for fluoride release, recharge, adhesion, and microleakage. Two experimental sealants (Exp-1, Exp-2) containing a synthesized antibacterial fluoride-releasing monomer and fluoride-releasing filler were formulated. Exp-2 also contained NovaMin nanoparticles. Commercial sealants Clinpro (CL) FluroShield (FS), and SeLECT Defense (E34) were also included. Fluoride release from disk samples in deionized water was measured daily using an ion-selective electrode for 14 days, and after recharging with Neutra-Foam (2.0% sodium fluoride), fluoride was measured for 5 days. Microtensile bonding strengths (MTBS) to enamel were tested after 24-hour storage in water at 37°C or thermocycling 5-55°C for 1,000 cycles. A microleakage test was conducted on extracted teeth using a dye-penetration method. The data were analyzed using analysis of variance with the Tukey's honestly significant difference test and Kruskal-Wallis test. Exp-1 and Exp-2 had significantly higher fluoride release and recharge capabilities than CL and FL (Psealants had similar MTBS before and after thermocycling. Exp-2 and Exp-1 had significantly lower microleakage scores (Psealants had higher fluoride release and recharge capabilities and similar or better retention than commercial sealants.

  17. [Allergy caused by sodium fluoride glycerin: a case report].

    Science.gov (United States)

    Ma, Jihong

    2012-04-01

    In recent years, though more and more ulcerations of oral mucosa caused by allergy to drug occurred clinically, allergy to sodium fluoride glycerin is extremely rare. A case of allergy to sodium fluoride glycerin occurred in Qianfoshan Campus Hospital of Shandong University. After treatment by sodium fluoride glycerin, there was mucosal edema, a large number of red miliary granules in buccal and palatal mucosa. After 3 hours, there were swallowing difficulties, but no breathing difficulties. Next day large ulcers of oral mucosa developed. The patient was cured 7 days after treatment. Fluoride-sensitive test result was positive.

  18. 4-phenylbutyrate Mitigates Fluoride-Induced Cytotoxicity in ALC Cells

    Directory of Open Access Journals (Sweden)

    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

  19. Formulation and Characterization of Antibacterial Fluoride-releasing Sealants

    Science.gov (United States)

    Fan, Yuwei; Townsend, Janice; Wang, Yapin; Lee, Eun Chee; Evans, Katie; Hender, Erica; Hagan, Joseph L.; Xu, Xiaoming

    2013-01-01

    Purpose The purpose of this study was to formulate and characterize experimental antibacterial fluoride-releasing sealants and compare them with commercial sealants for fluoride release, recharge, adhesion, and microleakage. Methods Two experimental sealants (Exp-1, Exp-2) containing a synthesized antibacterial fluoride-releasing monomer and fluoride-releasing filler were formulated. Exp-2 also contained NovaMin nanoparticles. Commercial sealants Clinpro (CL) FluoroShield (FS), and SeLECT Defense (E34) were also included. Fluoride release from disk samples in deionized water was measured daily using an ion-selective electrode for 14 days, and after recharging with Neutra-Foam (2.0% sodium fluoride), fluoride was measured for 5 days. Microtensile bonding strengths (MTBS) to enamel were tested after 24-hour storage in water at 37°C or thermocycling 5-55°C for 1,000 cycles. A microleakage test was conducted on extracted teeth using a dye-penetration method. The data were analyzed using analysis of variance with the Tukey’s honestly significant difference test and Kruskal-Wallis test. Results Exp-1 and Exp-2 had significantly higher fluoride release and recharge capabilities than CL and FL (P<.05). All tested sealants had similar MTBS before and after thermocycling. Exp-2 and Exp-1 had significantly lower microleakage scores (P<.05) than other groups. Conclusion The experimental sealants had higher fluoride release and recharge capabilities and similar or better retention than commercial sealants. PMID:23635887

  20. Survey of fluoride levels in vended water stations.

    Science.gov (United States)

    Jadav, Urvi G; Archarya, Bhavini S; Velasquez, Gisela M; Vance, Bradley J; Tate, Robert H; Quock, Ryan L

    2014-01-01

    This study sought to measure the fluoride concentration of water derived from vended water stations (VWS) and to identify its clinical implications, especially with regard to caries prevention and fluorosis. VWS and corresponding tap water samples were collected from 34 unique postal zip codes; samples were analyzed in duplicate for fluoride concentration. Average fluoride concentration in VWS water was significantly lower than that of tap water (P water ranged from drinking water may not be receiving optimal caries preventive benefits; thus dietary fluoride supplementation may be indicated. Conversely, to minimize the risk of fluorosis in infants consuming reconstituted infant formula, water from a VWS may be used.

  1. The dentist’s role in promoting community water fluoridation

    Science.gov (United States)

    Melbye, Molly L.R.; Armfield, Jason M.

    2013-01-01

    Background and Overview Community water fluoridation is an important public health intervention that reduces oral health disparities and increases the health of the population. Promotion of its safety and effectiveness is critical to maintaining its widespread acceptance and ensuring its continued use. Dentists are a potentially important source of knowledge regarding the oral health benefits and safety of water fluoridation. However, few dentists regularly discuss fluorides, and water fluoridation in particular, with patients. The authors aim to describe and discuss the role and importance of dentists’ promotion of public water fluoridation, barriers to dentists’ involvement and some approaches that might influence dentists to promote water fluoridation more actively. Conclusions and Practice Implications Ongoing promotion of fluoridation by dentists is a key factor in ensuring sustained municipal water fluoridation. However, current undergraduate dental curricula do not adequately prepare dentists for this role, and continuing dental education may be insufficient to change clinical practice. Although smoking-cessation literature can shed some light on how to proceed, changing dentists’ practice behavior remains a largely unstudied topic. Dental associations are a key resource for dentists, providing information that can assist them in becoming advocates for water fluoridation. PMID:23283928

  2. 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.

  3. Fluoridated milk for preventing dental caries.

    Science.gov (United States)

    Yeung, C Albert; Chong, Lee Yee; Glenny, Anne-Marie

    2015-09-03

    Dental caries remains a major public health problem in most industrialised countries, affecting 60% to 90% of schoolchildren and the vast majority of adults. Milk may provide a relatively cost-effective vehicle for fluoride delivery in the prevention of dental caries. This is an update of a Cochrane review first published in 2005. To assess the effects of milk fluoridation for preventing dental caries at a community level. We searched the Cochrane Oral Health Group Trials Register (inception to November 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2014, Issue 10), MEDLINE via OVID (1946 to November 2014) and EMBASE via OVID (1980 to November 2014). We also searched the U.S. National Institutes of Health Trials Register (https://clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (http://apps.who.int/trialsearch) for ongoing trials. We did not place any restrictions on the language or date of publication when searching the electronic databases. Randomised controlled trials (RCTs), with an intervention and follow-up period of at least two years, comparing fluoridated milk with non-fluoridated milk. Two authors independently assessed trial risk of bias and extracted data. We used standard methodological procedures expected by The Cochrane Collaboration. We included one unpublished RCT, randomising 180 children aged three years at study commencement. The setting was nursery schools in an area with high prevalence of dental caries and a low level of fluoride in drinking water. Data from 166 participants were available for analysis. The study carried a high risk of bias. After three years, there was a reduction of caries in permanent teeth (mean difference (MD) -0.13, 95% confidence interval (CI) -0.24 to -0.02) and in primary teeth (MD -1.14, 95% CI -1.86 to -0.42), as measured by the decayed, missing and filled teeth index (DMFT for permanent teeth and dmft for primary teeth). For primary teeth

  4. 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

  5. Determination of gold, indium, tellurium and thallium in the same sample digest of geological materials by atomic-absorption spectroscopy and two-step solvent extraction

    Science.gov (United States)

    Hubert, A.E.; Chao, T.T.

    1985-01-01

    A rock, soil, or stream-sediment sample is decomposed with hydrofluoric acid, aqua regia, and hydrobromic acid-bromine solution. Gold, thallium, indium and tellurium are separated and concentrated from the sample digest by a two-step MIBK extraction at two concentrations of hydrobromic add. Gold and thallium are first extracted from 0.1M hydrobromic acid medium, then indium and tellurium are extracted from 3M hydrobromic acid in the presence of ascorbic acid to eliminate iron interference. The elements are then determined by flame atomic-absorption spectrophotometry. The two-step solvent extraction can also be used in conjunction with electrothermal atomic-absorption methods to lower the detection limits for all four metals in geological materials. ?? 1985.

  6. Irradiation effects on microhardness of fluoridated and non-fluoridated bovine dentin

    Energy Technology Data Exchange (ETDEWEB)

    Kielbassa, A.M.; Beetz, I.; Hellwig, E. [Albert-Ludwigs-Univ., Univ. Clinic of Dentistry, Dept. of Operative Dentistry and Periodontology, Freiburg (Germany); Schendera, A. [Albert-Ludwigs-Univ., Univ. Clinic of Radiotherapy, Freiburg (Germany)

    1997-10-01

    The objective of this study was to evaluate the effects of irradiation on microhardness of dentin. Dentin blocks from the cervical region of bovine incisors were treated as follows: 1) no irradiation; 2) irradiation of specimens up to 60 Gy (2Gy/day, 5 days/week); 3) no irradiation, but fluoridation of specimens for 5 min/d; 4) irradiation of specimens and daily fluoridation. Knoop hardness number (KHN) of the control specimens was 62.63{+-}14.75 (mean{+-}SD). This was significantly different from the irradiated dentin samples (8.74{+-}2.59 KHN). Hardness of the fluoridated dentin specimens was 11.19{+-}1.95 KHN in the non-irradiated group and 10.03{+-}2.75 KHN in the irradiated groups, respectively. Within the limitations of an in vitro study, it is concluded that dentin is severely affected by irradiation. This could be an explanation for the frequently observed side-effects of irradiation like loss of enamel, gap formation at the amelodentinal junction, and caries of the cervical region. Fluoridation with acidic gels decereases microhardness of dentin surface, and does not prevent softening due to radiation, when saliva is absent. (au). 23 refs.

  7. CAN FLUORIDATION AFFECT LEAD (II) IN POTABLE WATER? HEXAFLUOROSILICATE AND FLUORIDE EQUILIBRIA IN AQUEOUS SOLUTION

    Science.gov (United States)

    Recent reports have attempted to show that fluoridating potable water is linked to increased levels of lead(II) in the blood. We examine these claims in light of the established science and critically evaluate their significance. The completeness of hexafluorosilicate hydrolysi...

  8. 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

    2017-11-28

    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 (LS8Sirt/KO) cells or CRISPR/dCas9/SAM-mediated Sirt1 overexpressing (LS8Sirt1/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 LS8Sirt/KO cells, whereas it decreased in LS8Sirt1/over. Fluoride-induced Ac-p53 formation was also suppressed in LS8Sirt1/over cells. Compared to WT cells, fluoride-induced Cdkn1a/p21 expression was elevated in LS8Sirt/KO and these cells were more susceptible to fluoride-induced growth inhibition. In contrast, LS8Sirt1/over cells were significantly more resistant. In addition, fluoride-induced cytochrome-c release and caspase-3 activation were suppressed in LS8Sirt1/over cells. Fluoride induced expression of the DNA double strand break marker γH2AX in WT cells and this was augmented in LS8Sirt1/KO cells, but was attenuated in LS8Sirt1/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.

  9. Comparison of fluoride uptake into tooth enamel from two fluoride varnishes containing different calcium phosphate sources.

    Science.gov (United States)

    Schemehorn, B R; Wood, G D; McHale, W; Winston, A E

    2011-01-01

    The objective of this in vitro study was to compare two 5% sodium fluoride varnishes, each containing different sources of calcium and phosphate, for their ability to deliver fluoride into treated sound tooth enamel and adjacent, but untreated demineralized enamel. Six sets of 12 bovine enamel cores were mounted in plexiglass rods and the exposed surfaces were polished. Synthetic lesions were formed in the surface of three sets by soaking in thickened, pH 5.0, 1M lactic acid, 50% saturated with calcium hydroxyapatite. A fluoride varnish containing tri-calcium phosphate (TCP) was applied to one set of sound enamel cores, and a second, delivering amorphous calcium phosphate (ACP), was applied to another. A third set of sound enamel cores was water-treated. Each treated sound core was paired with an untreated lesioned core, and the pairs were soaked in artificial saliva for 24 hours at 37 degrees C. The treated cores, but not their lesioned counterparts, were initially soaked in 1.0 N KOH saturated with calcium phosphate for 18 hours. Each core was separately etched with 1.0 N perchloric acid for exactly 15 seconds, and fluoride measured by an ion-sensitive electrode after neutralizing with NaOH and buffering in TISAB II. The amount of calcium extracted was also determined by atomic absorption spectrophotometry as a measure of etch depth. Fluoride uptake average was 1677 +/- 193 ppm, 455 + 38 ppm, and 44 +/- 5 ppm for the sound enamel cores treated with ACP varnish, TCP varnish, and water treatment, respectively. Fluoride uptake into the demineralized enamel averaged 5567 +/- 460 ppm, 2126 +/-126 ppm, and 49 -/+ 4 ppm for demineralized enamel paired with the sound cores treated with ACP varnish, TCP varnish, and water, respectively. The differences between the ACP varnish, the TCP varnish, and the water treatments were statistically significant (p < 0.05). The ACP varnish formulation delivers statistically significantly more fluoride to both intact and demineralized

  10. Fluoride concentrations in groundwater and impact on human health ...

    African Journals Online (AJOL)

    2010-07-04

    Jul 4, 2010 ... tal fluorosis in the Free State, North West, KwaZulu-Natal and. Western Cape Provinces was also assessed by Ncube and ... of fluoride-rich groundwater in the North-West and Limpopo. Provinces of South Africa. High fluoride ..... water of South Korea. Sci. Total Environ. 385 272–283. CLARKE S (2000) ...

  11. Fluoride release/recharging ability and bond strength of glass ...

    African Journals Online (AJOL)

    2015-08-17

    Aug 17, 2015 ... and erosion of GICs during the early setting period, followed by a rapid .... fluoride ions released from each specimen were measured at. 1, 2, 4, 8, 15, .... adhesion to enamel and dentin tissues and fluoride release are some of ...

  12. Fluoride release by glass ionomer cements, compomer and giomer

    Directory of Open Access Journals (Sweden)

    Sayed Mostafa Mousavinasab

    2009-01-01

    Conclusion:Fuji IX, Fuji VII, Fuji IX Extra, and Fuji II LC released higher amounts of fluoride compared to Beautifil and Dyract Extra in this study. It seems that the extent of the glass ionomer matrix plays an important role in determining the fluoride releasing ability of glass ionomer cement materials.

  13. Study of Fluoride Glasses Devitrification-Based Magnesium ...

    African Journals Online (AJOL)

    The kinetics of devitrification of fluoride glasses stabilized by magnesium fluoride when heated for some time between the glass transition and melting temperatures. The crystallization kinetics of AlF3-YF3-PbF2-CdF2-MgF2 glass prepared by melting the halide powders were studied by differential scanning calorimetry ...

  14. The occurrence of fluoride in South African groundwater: A water ...

    African Journals Online (AJOL)

    The fluoride data were obtained by extracting fluoride groundwater quality data from DWAF's Water Management Systems (WMS) database. STATISTICA and ARCVIEW were used to process the data. The dental fluorosis data were obtained from a field study conducted by the Department of Health. The degree of dental ...

  15. Fluoride in black and green tea ( Camellia sinensis ) infusions in ...

    African Journals Online (AJOL)

    The fluoride contents in the infusions of 21 commercially available Ethiopian and imported black and green tea brands; in leaf and bag forms was determined by a fluoride ion-selective electrode method. Of the samples analyzed twelve were products from Ethiopia and the remaining nine were imported tea brands.

  16. Fluoride Contamination in Drinking Water in the Rift Valley, Kenya ...

    African Journals Online (AJOL)

    A survey of the amount of Fluoride in ground, potable water in Njoro division, Nakuru district and some parts outside the division was conducted to determine the concentration of Fluoride the residents are consuming through water. This area is situated in the Great Rift Valley of East Africa, which is known to have high levels ...

  17. FLUORIDE IN BLACK AND GREEN TEA (CAMELLIA SINENSIS ...

    African Journals Online (AJOL)

    Preferred Customer

    ... mg/kg in black tea bags originated from United Kingdom, India, China, Japan, and ... salts are the main sources of the total fluoride intake of the population [20]. ..... older dust tea leaves which accumulate higher fluoride level through aging, ...

  18. Equilibrium Studies of Fluoride Adsorption onto a Ferric Poly ...

    African Journals Online (AJOL)

    African countries along the Great Rift Valley are among areas of the world where excess fluoride in water sources is a major public health problem. In this work, the removal of fluoride (F) from water solutions using a ferric poly-mineral (FPM) from Kenya was therefore studied using batch adsorption experiments. The effect of ...

  19. Fluoride release/recharging ability and bond strength of glass ...

    African Journals Online (AJOL)

    release as well as greater fluoride recharge capacity. Key words: Bond strength, caries-affected dentin, fluoride release, glass ionomer cements. Date of Acceptance: 17-Aug-2015. Introduction. The current concept of restorative dentistry is characterized by the preservation of tooth structure during cavity preparation and less ...

  20. Fluoride inhibits the response of bone cells to mechanical loading

    NARCIS (Netherlands)

    Willems, H.M.E.; van den Heuvel, E.G.H.M.; Castelein, S.; Buisman, J.K.; Bronckers, A.L.J.J.; Bakker, A.D.; Klein-Nulend, J.

    2011-01-01

    The response of bone cells to mechanical loading is mediated by the cytoskeleton. Since the bone anabolic agent fluoride disrupts the cytoskeleton, we investigated whether fluoride affects the response of bone cells to mechanical loading, and whether this is cytoskeleton mediated. The

  1. Brushing abrasion of eroded bovine enamel pretreated with topical fluorides

    NARCIS (Netherlands)

    Vieira, A; Lugtenborg, M; Ruben, JL; Huysmans, MCDNJM

    2006-01-01

    Topical fluorides have been proposed for the prevention of erosive dental wear. This study evaluated the in vitro effect of a single professional application of 4% titanium tetrafluoride (TiF4), 1% amine fluoride (AmF) and 0.1% difluorosilane varnish (FV) in preventing wear due to combined erosion

  2. Carbide-fluoride-silver self-lubricating composite

    Science.gov (United States)

    Sliney, Harold E. (Inventor)

    1987-01-01

    A self-lubricating, friction and wear reducing composite material is described for use over a wide temperature spectrum from cryogenic temperature to about 900 C in a chemically reactive environment comprising silver, barium fluoride/calcium fluoride eutectic, and metal bonded chromium carbide.

  3. Carbide/fluoride/silver self-lubricating composite

    Science.gov (United States)

    Sliney, Harold E. (Inventor)

    1988-01-01

    A self-lubricating, friction and wear reducing composite material for use over a wide temperature spectrum from cryogenic temperature to about 900.degree. C. in a chemically reactive environment comprising silver, barium fluoride/calcium fluoride eutectic, and metal bonded chromium carbide.

  4. Spectrophotometric determination of fluoride in drinking water using ...

    African Journals Online (AJOL)

    A sensitive spectrophotometric determination of fluoride in drinking water has been developed using aluminium complexes of triphenylmethane dyes (chrome azurol B and malachite green) as spectrophotometric reagents. The method allowed a reliable determination of fluoride in the range of 0.5–4.0 mg·l-1 for chrome ...

  5. Optical detection of sodium salts of fluoride, acetate and phosphate ...

    Indian Academy of Sciences (India)

    cal systems and they are also of health concern.1,2 Many synthetic chromogenic and/or fluorogenic sensors for fluoride ... not applicable in many bio-analytical applications. Of course, colourimetric detection of fluoride in ..... Hursthouse M B, Light M E, Shi A J 2002 Chem. Commun. 758; (c) Camiolo S, Gale P A, Hursthouse.

  6. Examination of Reviews-Outcomes of Community Water Fluoridation ...

    African Journals Online (AJOL)

    Examination of Reviews-Outcomes of Community Water Fluoridation in Dental Caries Prevention. ... West African Journal of Industrial and Academic Research ... The purpose of this paper is to examine the different reviews of the outcomes of fluoridation of community water in the prevention of dental caries in Cochrane ...

  7. Fluoride removal studies in water using natural materials : technical ...

    African Journals Online (AJOL)

    Excess fluoride in water causes health hazards to the natural environment. The removal of fluoride was attempted using natural materials such as red soil, charcoal, brick, fly-ash and serpentine. Each material was set up in a column for a known volume and the defluoridation capacities of these materials were studied with ...

  8. Fluoride removal from water by zirconium (IV) doped chitosan bio ...

    African Journals Online (AJOL)

    This bio-composite was at par with commercial alumina to mitigate water fluoride limit up to 1 to 1.5 mg/L. Effect of parameters namely pH, adsorbent dose, contact time and initial fluoride concentration were studied in batch scale. Kinetic data showed a rapid adsorption, indicated practicable operations in packed column.

  9. Spectrophotometric determination of fluoride in drinking water using ...

    African Journals Online (AJOL)

    2011-03-14

    Mar 14, 2011 ... A sensitive spectrophotometric determination of fluoride in drinking water has been developed using aluminium complexes of triphenylmethane dyes (chrome azurol B and malachite green) as spectrophotometric reagents. The method allowed a reliable determination of fluoride in the range of 0.5–4.0 ...

  10. Organometallic fluorides of main group and transition elements

    Indian Academy of Sciences (India)

    Administrator

    Organometallic fluorides of main group and transition elements. HERBERT W ROESKY. University of Gottingen, Gottingen, Germany. Me3SnF, Ph2PbF2 and Ph3BiF2 are used for the preparation of organometallic fluorides. Their different properties in fluorination reactions are discussed. The application of organometallic ...

  11. Potential groundwater contamination by fluoride from two South ...

    African Journals Online (AJOL)

    A study to investigate the fluoride content in two South African phosphogypsums, Kynoch and Omnia, and the potential threat to water sources was undertaken. Kynoch and Omnia phosphogypsums were found to consist of fluoride in the region of 0.12% and 0.03% by mass, respectively. The phosphogypsum samples were ...

  12. Combined aluminium sulfate/hydroxide process for fluoride removal ...

    African Journals Online (AJOL)

    The fluoride removal efficiency of the combined process was also tested for real water sample from selected community water supply system in the Rift Valley Region of Ethiopia. The removal of fluoride was rapid in the first 15 min. The combined process efficiency was about 93% with an optimum combined alum/AO dose ...

  13. Fluoride Analysis. Training Module 5.200.2.77.

    Science.gov (United States)

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with fluoride analysis procedures. Included are objectives, an instructor guide, student handouts, and a list of reference material. This module considers the determination of fluoride in water supplies using the SPANDS and electrode…

  14. Hydrolysis of iron and chromium fluorides: mechanism and kinetics.

    Science.gov (United States)

    Gálvez, José L; Dufour, Javier; Negro, Carlos; López-Mateos, Federico

    2008-06-15

    Fluoride complexes of metallic ions are one of the main problems when processing industrial effluents with high content of fluoride anion. The most important case is derived from pickling treatment of stainless steel, which is performed with HNO3/HF mixtures to remove oxides scale formed over the metal surface. Waste from this process, spent pickling liquor, must be treated for recovering metallic and acid content. Conventional treatments produce a final effluent with high quantity of fluoride complexes of iron and chromium. This work proposes a hydrolysis treatment of these solid metal fluorides by reacting them with a basic agent. Metal oxides are obtained, while fluoride is released to solution as a solved salt, which can be easily recovered as hydrofluoric acid. Solid iron and chromium fluorides, mainly K2FeF5(s) and CrF3(s), obtained in the UCM treatment process, were employed in this work. Optimal hydrolysis operating conditions were obtained by means of a factorial design: media must be basic but pH cannot be higher than 9.5, temperature from 40 to 70 degrees C and alkali concentration (potassium hydroxide) below 1.1 mol L(-1). Secondary reactions have been detected, which are probably due to fluoride adsorption onto obtained oxides surface. Mechanism of reaction consists of several stages, involving solid fluoride dissolution and complexes decomposition. Hydrolysis kinetics has been modeled with classical crystal dissolution kinetics, based on mass transfer phenomena.

  15. Computational investigation of the role of fluoride in Tamao oxidations

    DEFF Research Database (Denmark)

    Mader, Mary M.; Norrby, Per-Ola

    2002-01-01

    The Tamao oxidation of alkoxysilanes was investigated computationally to determine the role of fluoride. a key additive. in this reaction. A sequence of fluoride equilibria as well as possible transition states. mediated by basic and neutral peroxide, respectively, were examined, and a potential...

  16. 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.

  17. Mechanisms of action of fluoride for caries control

    NARCIS (Netherlands)

    Buzalaf, M.A.R.; Pessan, J.P.; Honório, H.M.; ten Cate, J.M.; Buzalaf, M.A.R.

    2011-01-01

    Fluoride was introduced into dentistry over 70 years ago, and it is now recognized as the main factor responsible for the dramatic decline in caries prevalence that has been observed worldwide. However, excessive fluoride intake during the period of tooth development can cause dental fluorosis. In

  18. Household water sources and their contribution towards fluoride ...

    African Journals Online (AJOL)

    Fluoride is regarded as an essential element for the formation of healthy bones and teeth. However, high fluoride levels in drinking water have been associated with high incidences of dental fluorosis. A 1996–1997 study in Njoro Division, Nakuru District, established that the groundwater used for cooking and drinking, ...

  19. Comparative effect of a stannous fluoride toothpaste and a sodium fluoride toothpaste on a multispecies biofilm.

    Science.gov (United States)

    Cheng, Xingqun; Liu, Jinman; Li, Jiyao; Zhou, Xuedong; Wang, Lijiang; Liu, Jiquan; Xu, Xin

    2017-02-01

    This paper aimed to compare the mode of action of a stannous fluoride-containing toothpaste with a conventional sodium fluoride-containing toothpaste on anti-biofilm properties. A three-species biofilm model that consists of Streptococcus mutans, Streptococcus sanguinis and Porphyromonas gingivalis was established to compare the anti-biofilm properties of a stannous fluoride-containing toothpaste (CPH), a conventional sodium fluoride-containing toothpaste (CCP) and a negative control (PBS). The 48h biofilms were subjected to two-minute episodes of treatment with test agents twice a day for 5 consecutive days. Crystal violet staining and XTT assays were used to evaluate the biomass and viability of the treated biofilm. Live/dead staining and bacteria/extracellular polysaccharides (EPS) double-staining were used to visualize the biofilm structure and to quantify microbial/extracellular components of the treated biofilms. Species-specific fluorescent in situ hybridization and quantitative polymerase chain reaction (qPCR) were used to analyze microbial composition of the biofilms after treatment. The biomass and viability of the biofilms were significantly reduced after CPH toothpaste treatment. The inhibitory effect was further confirmed by the live/dead staining. The EPS amounts of the three-species biofilm were significantly reduced by CCP and CPH treatments, and CPH toothpaste demonstrated significant inhibition on EPS production. More importantly, CPH toothpaste significantly suppressed S. mutans and P. gingvalis, and enriched S. sanguinis in the three-species biofilm. In all experiments CPH had a significantly greater effect than CCP (pbiofilm, but was also able to modulate microbial composition within multi-species biofilm compared with conventional sodium fluoride-containing toothpaste. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Anti Streptococcus mutans non fluoride and fluoride containing sealants after adding nano-silver particles

    Directory of Open Access Journals (Sweden)

    Maryam Ghasempour

    2014-04-01

    Full Text Available   Background and Aims: Since recurrent caries are one of the major causes of failure in resin restorations, the production of antibacterial resin composites was always under investigation. The aim of this study was to evaluate the efficacy of fissure sealants containing nanosilver particles against the Streptococcus mutans.   Materials and Methods: In this experimental study, the antibacterial properties of two sealants (with fluoride (Clinpro 3M and without fluoride (Concise 3M was investigated with 0, 0.01, 0.02, 0.03, 0.04, 0.05% w/w after adding nano-silver using direct contact test. Sealants formed on the walls of 500ml micro tube and after curing, they left in contact with bacterial suspension. In periods of 3, 24, 48h, a 10 µl volume of liquid medium was placed in blood agar culture and after 24 h incubation at 37ºC, the number of S.mutans colony was counted by colony counter. Data were analyzed using ANOVA andT-test.   Results: Results reported sealants with fluoride comparing to non fluoride ones had significant effect on inhibition of S.mutans growth (P<0.001. The direct contact test demonstrated that by increasing the amount of nano particles, the bacterial growth was significantly diminished (P<0.001.   Conclusion: While sealants with fluoride demonstrated antibacterial effect, sealants with incorporation of higher weight percentage of nanosilver particles, had stronger and more significant antibacterial effect in direct contact test.

  1. Fluoride microresonators for mid-IR applications

    CERN Document Server

    Grudinin, Ivan S; Yu, Nan

    2016-01-01

    We study crystalline fluoride microresonators for mid-infrared applications. Whispering gallery mode resonators were fabricated with BaF$_2$, CaF$_2$ and MgF$_2$ crystals. The quality factors were measured at wavelengths of 1.56 {\\mu}m and 4.58 {\\mu}m. The impacts of fabrication technique, impurities, multiphonon absorption and surface water are investigated. It is found that MgF2 resonators have room temperature Q factor of $8.3\\times 10^6$ at wavelength of 4.58 {\\mu}m, limited by multiphonon absorption.

  2. Fluoride use in Controlling Dental Caries and Fluorosis

    Directory of Open Access Journals (Sweden)

    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.

  3. Prevention of dental caries through the effective use of fluoride

    DEFF Research Database (Denmark)

    Petersen, Poul Erik

    2016-01-01

    Background: The World Health Organization (WHO) emphasizes that dental caries is a severe public health problem across the world. The current global and regional patterns of dental caries reflect distinct risk profiles of countries which relate to the structure of the society, living conditions......, lifestyles, and the existence of preventive oral health programmes. Research conducted in high income countries documents that systematic use of fluoride reduces the burden of dental caries; such research is scarce in low and middle income countries. Objectives: This article reviews the evidence on effective...... use of fluoride, highlights the public health approach to fluoridation, and clarifies how automatic fluoridation contributes to breaking social inequities in dental caries. Data collection: Scientific publications on fluoride administration stored in PubMed/Medline and caries data from the WHO...

  4. Fluorides in groundwater and its impact on health.

    Science.gov (United States)

    Shailaja, K; Johnson, Mary Esther Cynthia

    2007-04-01

    Fluoride is a naturally occurring toxic mineral present in drinking water and causes yellowing of teeth, tooth problems etc. Fluorspar, Cryolite and Fluorapatite are the naturally occurring minerals, from which fluoride finds its path to groundwater through infiltration. In the present study two groundwater samples, Station I and Station II at Hyderabad megacity, the capital of Andhra Pradesh were investigated for one year from January 2001 to December 2001. The average fluoride values were 1.37 mg/l at Station I and 0.91 mg/l at Station II. The permissible limit given by BIS (1983) 0.6-1.2 mg/l and WHO (1984) 1.5 mg/l for fluoride in drinking water. The groundwaters at Station I exceeded the limit while at Station II it was within the limits. The study indicated that fluoride content of 0.5 mg/l is sufficient to cause yellowing of teeth and dental problems.

  5. The fractional urinary fluoride excretion of adults consuming naturally and artificially fluoridated water and the influence of water hardness: a randomized trial.

    Science.gov (United States)

    Villa, A; Cabezas, L; Anabalón, M; Rugg-Gunn, A

    2009-09-01

    To assess whether there was any significant difference in the average fractional urinary fluoride excretion (FUFE) values among adults consuming (NaF) fluoridated Ca-free water (reference water), naturally fluoridated hard water and an artificially (H2SiF6) fluoridated soft water. Sixty adult females (N=20 for each treatment) participated in this randomized, double-blind trial. The experimental design of this study provided an indirect estimation of the fluoride absorption in different types of water through the assessment of the fractional urinary fluoride excretion of volunteers. Average daily FUFE values (daily amount of fluoride excreted in urine/daily total fluoride intake) were not significantly different between the three treatments (Kruskal-Wallis; p = 0.62). The average 24-hour FUFE value (n=60) was 0.69; 95% C.I. 0.65-0.73. The results of this study suggest that the absorption of fluoride is not affected by water hardness.

  6. Preparation and optimization of calcium fluoride particles for dental applications.

    Science.gov (United States)

    Koeser, Joachim; Carvalho, Thiago Saads; Pieles, Uwe; Lussi, Adrian

    2014-07-01

    Fluorides are used in dental care due to their beneficial effect in tooth enamel de-/remineralization cycles. To achieve a desired constant supply of soluble fluorides in the oral cavity, different approaches have been followed. Here we present results on the preparation of CaF2 particles and their characterization with respect to a potential application as enamel associated fluoride releasing reservoirs. CaF2 particles were synthesized by precipitation from soluble NaF and CaCl2 salt solutions of defined concentrations and their morphology analyzed by scanning electron microscopy. CaF2 particles with defined sizes and shapes could be synthesized by adjusting the concentrations of the precursor salt solutions. Such particles interacted with enamel surfaces when applied at fluoride concentrations correlating to typical dental care products. Fluoride release from the synthesized CaF2 particles was observed to be largely influenced by the concentration of phosphate in the solution. Physiological solutions with phosphate concentration similar to saliva (3.5 mM) reduced the fluoride release from pure CaF2 particles by a factor of 10-20 × as compared to phosphate free buffer solutions. Fluoride release was even lower in human saliva. The fluoride release could be increased by the addition of phosphate in substoichiometric amounts during CaF2 particle synthesis. The presented results demonstrate that the morphology and fluoride release characteristics of CaF2 particles can be tuned and provide evidence of the suitability of synthetic CaF2 particles as enamel associated fluoride reservoirs.

  7. 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.

  8. 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.

  9. Influence of Growth Mode and Sucrose on Susceptibility of Streptococcus sanguis to Amine Fluorides and Amine Fluoride-Inorganic Fluoride Combinations

    Science.gov (United States)

    Embleton, J. V.; Newman, H. N.; Wilson, M.

    1998-01-01

    This study evaluated the susceptibility to amine fluorides (AmFs) of planktonic and biofilm cultures of Streptococcus sanguis grown with and without sucrose. Cultures were incubated with AmFs (250 mg of fluoride liter−1) for 1 min. The susceptibility of biofilms was less than that of the planktonic form and was further decreased by growth in the presence of sucrose. PMID:9726905

  10. Industrial Applications of Graphite Fluoride Fibers

    Science.gov (United States)

    Hung, Ching-Cheh; Kucera, Donald

    1991-01-01

    Based on fluorination technology developed during 1934 to 1959, and the fiber technology developed during the 1970s, a new process was developed to produce graphite fluoride fibers. In the process, pitch based graphitized carbon fibers are at first intercalated and deintercalated several times by bromine and iodine, followed by several cycles of nitrogen heating and fluorination at 350 to 370 C. Electrical, mechanical, and thermal properties of this fiber depend on the fluorination process and the fluorine content of the graphite fluoride product. However, these properties are between those of graphite and those of PTFE (Teflon). Therefore, it is considered to be a semiplastic. The physical properties suggest that this new material may have many new and unexplored applications. For example, it can be a thermally conductive electrical insulator. Its coefficient of thermal expansion (CTE) can be adjusted to match that of silicon, and therefore, it can be a heat sinking printed circuit board which is CTE compatible with silicon. Using these fibers in printed circuit boards may provide improved electrical performance and reliability of the electronics on the board over existing designs. Also, since it releases fluorine at 300 C or higher, it can be used as a material to store fluorine and to conduct fluorination. This application may simplify the fluorination process and reduce the risk of handling fluorine.

  11. Susceptibility of Freesia to hydrogen fluoride

    Energy Technology Data Exchange (ETDEWEB)

    Wolting, H.G.

    1973-01-01

    Freesia's are very sensitive to hydrogen-fluoride. If they are exposed for a long period to concentrations between 0.5 and 0.9 part per billion several cultivars may show a severe damage. Differences in susceptibility between the varieties appear to exist. Some varieties that were heavily injured by HF had almost no flowers and a much lower yield of corns. After fumigation during a long period with very low concentrations of HF, besides the damage characteristic for HF (necrotic leaf tips and margins) there appeared oblong brown spots and stripes between the veins, which mimic the symptoms caused by the third freesia virus, also called bladnecrose. Some of the cultivars show this effect rather generally, in others it occurs only in a few plants. It could be demonstrated with the cultivars Rose Marie and Royal Blue that the sensitivity for HF increases by the presence of bladnecrose. This points to a synergistic action of hydrogen fluoride and the bladnecrose virus.

  12. Comparison of glucose-insulin-thallium-201 infusion single photon emission computed tomography (SPECT), stress-redistribution-reinjection thallium-201 SPECT and low dose dobutamine echocardiography for prediction of reversible dysfunction

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, Hiroki; Kondo, Makoto; Motohiro, Masayuki; Usami, Satoru [Shimada Municipal Hospital, Shizuoka (Japan)

    2001-12-01

    The usefulness of glucose-insulin-thallium-201 (GI-Tl) infusion single photon emission computed tomography (SPECT) in predicting reversible dysfunction has not been evaluated, so the present study recruited 20 patients with regional ischemic dysfunction for investigation. All patients underwent GI-Tl SPECT, post-stress Tl reinjection imaging and low dose dobutamine echocardiography. The diagnostic accuracy of these 3 techniques in predicting functional recovery was evaluated by receiver operating characteristic (ROC) analysis. In segments with functional recovery, regional Tl activities of GI-Tl SPECT were significantly higher than those of reinjection imaging (p<0.05), although there were no significant differences in segments without recovery. The area under the ROC curve for GI-Tl SPECT (0.75{+-}0.06) was greater than that for reinjection imaging (0.68{+-}0.07). The optimal cutoff values to identify viable myocardium were considered to be 55% of peak activity for GI-Tl SPECT and 50% for reinjection imaging. At this cutoff point, the sensitivity and specificity for detection of functional recovery were, respectively, 85% and 61% for GI-Tl SPECT, and 73% and 61% for reinjection imaging. Dobutamine echocardiography had the same sensitivity (85%), but lower specificity (48%) than GI-Tl SPECT. Continuous infusion of GI-Tl solution enhances regional Tl uptake compared with conventional post-stress reinjection imaging. This study suggests that GI-Tl SPECT is superior to reinjection imaging and dobutamine echocardiography in predicting functional recovery after ischemic left ventricular dysfunction. (author)

  13. [Differential approach to spring water choice regarding fluoride content for caries prevention].

    Science.gov (United States)

    Makeeva, I M; Protsenko, A S; Svistunova, E G

    2013-01-01

    The research includes an investigation of the tap water in different districts of Moscow. It was found out that Moscow tap water contains little fluoride, the difference between districts and okrugs is of no consequence. There is no centralized water fluoridization in Moscow therefore the authors suggest using bottled potable water with sufficient fluoride level. The fluoride concentration in one hundred of the most popular and wide-spread bottled potable water labels was examined. High in fluoride and low in fluoride labels were identified as well as the labels with the optimal fluoride content. Some practical guidelines for selection of bottled potable water depending on the quantity of liquid consummation were elaborated.

  14. [Ethical aspects of the fluoridation of water, salt, and milk].

    Science.gov (United States)

    Rippe, K P

    2009-05-01

    The article discusses two ethical aspects of the fluoridation of water, salt, and milk. First, it considers whether fluoridation contradicts the right of self-determination. Second, it discusses the chances and risks of fluoridation. The answer to the first question depends on whether people can choose other options. Freedom of choice is not simply the right to choose between different options. It is a right which defends the moral integrity of persons. Nobody should be coerced to eat or drink something which he or she rejects morally. In the political sphere, personal rights of persons can be restricted if and only if it is necessary, if there is a public interest, and if the restriction of the right is reasonable. Regarding fluoridation, even in the best risk-chance scenario, some persons have to expect a net harm. Therefore, the reasoning in favor of fluoridation has to have a specific purpose. The proclaimed reasoning is that fluoridation will benefit the worst off and is therefore a demand of justice. But this argument fails as there are other options to benefit the worst off. Even in the best risk-chance scenario, only one option is morally permissible: the fluoridation of salt, which respects the freedom of choice.

  15. Chitosan microparticles for the controlled delivery of fluoride.

    Science.gov (United States)

    Keegan, Gemma M; Smart, John D; Ingram, Matthew J; Barnes, Lara-Marie; Burnett, Gary R; Rees, Gareth D

    2012-03-01

    To manufacture and characterise chitosan/fluoride microparticles prepared by spray drying and assess their utility as controlled release vehicles for fluoride. Microparticles were manufactured from dispersions containing 1.0% and 2.0% (w/v) chitosan and 0.20% or 0.40% (w/v) NaF in the absence/presence of glutaraldehyde. Particle size distributions were determined using laser diffraction; fluoride loading and release were determined by ion-selective electrode. Release profiles were studied in isotonic media (pH 5.5) over 360 min; microparticles exhibiting greatest cumulative fluoride release were further evaluated at pH 4.0 and 7.0. Particle morphology was investigated using environmental scanning electron microscopy. Bioadhesion parameters were determined with a texture-probe analyser. Microparticles exhibited low polydispersity and volume mean diameters (VMDs) products to provide increased protection against caries, however further work is required to demonstrate this principle in vivo. Spray-drying is a low-cost route for the manufacture of bioadhesive chitosan/fluoride microparticles which can be exploited as controlled fluoride release agents to aid fluoride retention in the oral cavity. The potential exists to optimise release profiles to suit the delivery format thereby maximising the cariostatic benefits. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. 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 se......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...

  17. US drinking water: fluoridation knowledge level of water plant operators.

    Science.gov (United States)

    Lalumandier, J A; Hernandez, L C; Locci, A B; Reeves, T G

    2001-01-01

    We determined the knowledge level of water plant operators who fluoridate drinking water, and we compared small and large water plants. A pretested survey was sent to 2,381 water plant operators in 12 states that adjust the fluoride concentration of drinking water. A z-test for proportion was used to test for statistical difference between small and large plants at alpha = 0.05. Small water plants were those treating less than 1 million gallons of water daily. Eight hundred small and 480 large water plant operators responded, resulting in a response rate of 54 percent. Two-thirds of water plant operators correctly identified the optimal fluoride level, but more than 20 percent used a poor source for choosing the optimal level. Only one-fourth of operators were able to maintain the fluoride concentration to within 0.1 mg/L of the optimal concentration. A significantly greater proportion of operators at large water plants than at small water plants reported that they were able to maintain a fluoride concentration to within 0.1 mg/L of the optimal concentration (33.5% vs 21.3%, z = 4.74, P fluoride level, small water plant operators were less likely to use accurate reasoning for choosing that level and in maintaining fluoride concentrations within 0.1 mg/L of that level than large water plant operators.

  18. Amelioration of Fluoride Toxicity with the Use of Indigenous Inputs

    Directory of Open Access Journals (Sweden)

    Maitra A.

    2013-08-01

    Full Text Available An assessment was undertaken to study the efficacy of bacterial consortia isolated from different sources viz. rhizosphere of rice plant, oil spill sites of a petrol pump and from the sludge of a pharmaceutical waste water drain against the impact of fluoride. The experiments were conducted with two crops. In this mung bean experiment Vigna radiata was selected as a test crop. The seeds were sown in the field with bacterial consortia, compost and reduced dose (25% less nitrogen than recommended dose of chemical fertilizer. After 30days of seed sowing (DAS, plants were collected from the field and dipped into the sodium fluoride solution with different concentrations for 48 hours. Thereafter, the impact of fluoride on chlorophyll, sugar, proline and relative water content (% were evaluated. Scanning electron microscopy (SEM of the stem section was performed. SEM studies revealed that anatomical structure deformed with 1.5 mg/l sodium fluoride solution. It was observed that such treatment combination during the sowing of crops leads to combat the impact of lower doses of sodium fluoride (0.2 mg/l. Another experiment was also conducted within plastic pots with and without bacterial consortia isolated from rhizosphere of rice plant and oil spilled soil of petrol pump with the same field soil. Each pot was filled with 5 kg of soil + 2lt of water (on the basis of soil saturation. Oryza sativa seedlings were transplanted with different strength of sodium fluoride solution (25 mgNaF/kg, 50 mgNaF/kg, 100 mgNaF/kg and 500mgNaF/kg within the above pots. In second experiment, rice plants dried in all pots after 500 mgNaF/kg concentration of sodium fluoride. In this pot experiment bacterial strain are capable of reducing fluoride content in soil as noted by measuring fluoride in the pot soil after the experiment.

  19. Fluoride induced endoplasmic reticulum stress and calcium overload in ameloblasts.

    Science.gov (United States)

    Zhang, Ying; Zhang, KaiQiang; Ma, Lin; Gu, HeFeng; Li, Jian; Lei, Shuang

    2016-09-01

    The aim of the study was to evaluate the involvement of endoplasmic reticulum stress and intracellular calcium overload on the development of dental fluorosis. We cultured and exposed rat ameloblast HAT-7 cells to various concentrations of fluoride and measured apoptosis with flow cytometry and intracellular Ca2+ changes using confocal microscopy, investigated the protein levels of GRP78, calreticulin, XBP1 and CHOP by western blotting, and their transcriptional levels with RT-PCR. We also created an in vivo model of dental fluorosis by exposing animals to various concentrations of fluoride. Subsequently, thin dental tissue slices were analyzed with H&E staining, immunohistochemical staining, and transmission electron microscopy, TUNEL assay was also performed on dental tissue slices for assessment of apoptosis. High fluoride concentration was associated with decreased ameloblast proliferation, elevated ameloblast apoptosis, and increased intracellular Ca2+ in vitro. The translation and transcription of the proteins associated with endoplasmic reticulum stress were significantly elevated with high concentrations of fluoride. Based on immunohistochemical staining, these proteins were also highly expressed in animals exposed to high fluoride concentrations. Histologically, we found significant fluorosis-like changes in tissues from animals exposed to high fluoride concentrations. Transmission electron microscopy cytology indicated significant apoptotic changes in tissues exposed to high concentrations of fluoride. These results indicate that exposure to high levels of fluoride led to endoplasmic reticulum stress which induced apoptosis in cultured ameloblasts and in vivo rat model, suggesting an important role of calcium overload and endoplasmic reticulum stress triggered by high concentrations of fluoride in the development of dental fluorosis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. 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.

  1. Drinking water fluoridation and oral health inequities in Canadian children.

    Science.gov (United States)

    McLaren, Lindsay; Emery, J C Herbert

    2012-02-01

    One argument made in favour of drinking water fluoridation is that it is equitable in its impact on oral health. We examined the association between exposure to fluoridation and oral health inequities among Canadian children.PARTICIPANTS, SETTING AND INTERVENTION: We analyzed data from 1,017 children aged 6-11 from Cycle 1 of the Canadian Health Measures Survey, a cross-sectional, nationally representative survey that included a clinic oral health examination and a household interview. The outcome measure was a count of the number of decayed, missing (because of caries or periodontal disease) or filled teeth, either deciduous or permanent (dmftDMFT). Data were analyzed using linear (ordinary least squares) and multinomial logistic regression; we also computed the concentration index for education-related inequity in oral health. Water fluoridation status (the intervention) was assigned on the basis of the site location of data collection. Fluoridation was associated with better oral health (fewer dmftDMFT), adjusting for socio-economic and behavioural variables, and the effect was particularly strong for more severe oral health problems (three or more dmftDMFT). The effect of fluoridation on dmftDMFT was observed across income and education categories but appeared especially pronounced in lower education and higher income adequacy households. dmftDMFT were found to be disproportionately concentrated in lower-education households, though this did not vary by fluoridation status. The robust main effect of fluoridation on dmftDMFT and the beneficial effect across socio-economic groups support fluoridation as a beneficial and justifiable population health intervention. Fluoridation was equitable in the sense that its benefits were particularly apparent in those groups with the poorest oral health profiles, though the nature of the findings prompts consideration of the values underlying the judgement of health equity.

  2. Metal Fluoride Complexes of Na,K-ATPase

    Science.gov (United States)

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

    2011-01-01

    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+·Pi 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. PMID:21708939

  3. Detection and dosimetry of gamma ray emitted from thallium-201 and technetium-99m based on chemiluminescence technique

    Energy Technology Data Exchange (ETDEWEB)

    Shourian, Mostafa [Laboratory of Microanalysis, Institute of Biochemistry and Biophysics, University of Tehran, P.O. Box 13145-1384, Tehran (Iran, Islamic Republic of); Tavakoli, Hassan, E-mail: tavakoli@ibb.ut.ac.i [Faculty of Medicine, Department of Physiology and Biophysics, Faculty of Medicine, Baqiyatollah University of Medical Sciences, P.O. Box 19395-6558, Tehran (Iran, Islamic Republic of); Ghourchian, Hedayatollah, E-mail: hadi@ibb.ut.ac.i [Laboratory of Microanalysis, Institute of Biochemistry and Biophysics, University of Tehran, P.O. Box 13145-1384, Tehran (Iran, Islamic Republic of); Rafiee-Pour, Hossain-Ali [Laboratory of Microanalysis, Institute of Biochemistry and Biophysics, University of Tehran, P.O. Box 13145-1384, Tehran (Iran, Islamic Republic of)

    2010-09-15

    This report describes the detection and dosimetry of gamma ray emitted from Thallium-201 ({sup 201}Tl) and Technetium-99m ({sup 99m}Tc) based on chemiluminescence technique. H{sub 2}O{sub 2} produced by two gamma emitter radioisotopes of {sup 201}Tl and {sup 99m}Tc were quantitatively measured by chemiluminescence method. Upon producing H{sub 2}O{sub 2} in a luminol alkaline solution, in the presence of diperiodatocuprate, as catalyst a chemical reaction was accrued and consequently the emitted light was measured. The determined H{sub 2}O{sub 2} concentration was correlated with the gamma ray detection and dosimetry. The sensitivity of chemiluminescence technique for {sup 201}Tl and {sup 99m}Tc dosimetry was determined to be 0.20 and 0.08 MBq/l (Mega Becquerel per liter) respectively (R.S.D. = %5, N = 3). The plotted calibration curves showed detection limits of 3.24 and 1.76 MBq/l for {sup 201}Tl and {sup 99m}Tc, respectively.

  4. Myocardial infarction diagnosis with body surface potential mapping, electrocardiography, vectorcardiography and thallium-201 scintigraphy: a correlative study with left ventriculography.

    Science.gov (United States)

    Ackaoui, A; Nadeau, R; Sestier, F; Savard, P; Primeau, R; Lemieux, R; Descary, M C

    1985-01-01

    In 35 subjects with typical or atypical angina and/or documented myocardial infarction (MI), body surface potential maps (BSPMs), ECG, VCG and rest Thallium-201 (T1-201) have been compared to left ventriculography (LVG). BSPMs were recorded with 26 ECGs, and BSPM abnormalities for MI cases were considered to be areas of normally positive potentials that have become negative. Subjects with MI were classified according to the segmental localization and degree of asynergy on LVG. Moderate anterolateral and apical asynergy were found to correlate with BSPM diagnosis of anterolateral MI and ischemia, severe anterolateral and apical asynergy with BSPM diagnosis of anterolateral MI and ischemia, and moderate diaphragmatic and/or posterobasal asynergy with BSPM diagnosis of posterior MI. Simultaneous anterior and posterior asynergy were found for BSPM diagnosis of anterior with posterior MI. Subjects with no LVG asynergy had normal BSPMs. BSPM diagnosis had the highest correlation coefficient with the LVG diagnosis (r = 0.88). ECG and VCG showed similar results with r = 0.65 and 0.71 respectively, while T1-201 had r = 0.55. The examination of our BSPMs, as well as the ECG, VCG and T1-201, did not permit to detect apical damage in presence of anterior MI, and posterobasal damage in the presence of inferoposterior MI. It is concluded that BSPMs are slightly superior to ECG and VCG for diagnosis of MI.

  5. Thallium release from acid mine drainages: Speciation in river and tap water from Valdicastello mining district (northwest Tuscany).

    Science.gov (United States)

    Campanella, Beatrice; Casiot, Corinne; Onor, Massimo; Perotti, Martina; Petrini, Riccardo; Bramanti, Emilia

    2017-08-15

    In this work we present an advantageous method for the simultaneous separation and detection of Tl(I) and Tl(III) species through ion chromatography coupled with on-line inductively coupled plasma - mass spectrometry. Chromatographic separation between Tl(III) and Tl(I) was achieved in less than two minutes. The method was validated by recovery experiments on real samples, and by comparing the sum of the concentrations of individual Tl species with total thallium values obtained from continuous flow ICP-MS. The experimental procedure offers an accurate, sensitive and interference-free method for Tl speciation at trace levels in environmental samples. This allowed us to investigate the Tl speciation in acid mine drainages (AMD), surface waters and springs in a mining catchment in Valdicastello Carducci (Tuscany, Italy), where severe Tl contamination ad been evidenced previously. This study shows for the first time that Tl(III), in addition to Tl(I), is present in considerable amounts in water samples affected by acid mining outflow, raising the question of the origin of this thermodynamically unstable species. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Fluoride Levels in Water, Animal Feeds, Cow Milk, Cow Urine and ...

    African Journals Online (AJOL)

    The mean (0.25mg F/L) fluoride concentration in water for all the societies was below the tolerance level of fluoride for dairy cows of 3-6mgFL-1.one hundred and thirty dairy milk and 106 urine samples of dairy cattle were obtained for fluoride analysis. The mean fluoride level in milk was 0.0066 + 0.14mgF/kg. Milk fluoride ...

  7. Comparative antiplaque effectiveness of an essential oil and an amine fluoride/stannous fluoride mouthrinse.

    Science.gov (United States)

    Riep, B G; Bernimoulin, J P; Barnett, M L

    1999-03-01

    The adjunctive use of antimicrobial mouthrinses to help control supragingival plaque and gingivitis has been shown to contribute significantly to patients' daily oral hygiene regimens. This controlled clinical study used an observer-blind, randomized, cross-over design in a 4-day plaque regrowth model to determine the relative efficacies of an essential oil-containing mouthrinse (Listerine Antiseptic) and an amine fluoride/stannous fluoride-containing mouthrinse (Meridol) in inhibiting the development of supragingival plaque. A 0.1% chlorhexidine mouthrinse (Chlorhexamed-Fluid) was used as a positive control, and a 5% hydroalcohol solution was used as a negative control. Dosing for each of the test mouthrinses was based on the manufacturers' label directions. Because the volume and rinse time for each of the test mouthrinses were different, each test mouthrinse had its own negative control group. On day 1 of each test period, subjects received an oral soft and hard tissue examination and a dental prophylaxis to remove all plaque, calculus, and extrinsic stain. Starting the same day, subjects refrained from all mechanical oral hygiene procedures for the next 4 days and rinsed 2x daily under supervision with their randomly-assigned mouthrinse. On day 5, each subject received a plaque assessment as well as an oral examination to assess side effects. Each test period was separated by a 2-week washout period. 23 volunteers with a median age of 26 years completed the study. Compared to the respective placebos, the median percent plaque reductions at 5 days were 23.0%, 12.2%, and 38.2% for the essential oil, amine/stannous fluoride, and chlorhexidine rinses, respectively. The plaque reductions seen in the essential oil and chlorhexidine rinse groups were statistically significant (p 0.05). Additionally, the essential oil rinse was significantly more effective (p < 0.001) than the amine/stannous fluoride rinse in inhibiting plaque accumulation in this clinical model.

  8. Micronutrients in parenteral nutrition: boron, silicon, and fluoride.

    Science.gov (United States)

    Nielsen, Forrest H

    2009-11-01

    Boron may be beneficial for bone growth and maintenance, central nervous system function, and the inflammatory response, and silicon may be beneficial for bone maintenance and wound healing. Fluoride is not an essential element but amounts provided by contamination may be beneficial for bone strength. Fluoride toxicity may be a concern in parenteral nutrition. Further studies are warranted to determine whether there are optimal amounts of boron and silicon that should be delivered to typical and special population patients receiving parenteral nutrition. In addition, further studies are needed to determine whether providing the dietary guideline of adequate intake amounts of fluoride parenterally would prevent or treat parenteral nutrition osteopenia.

  9. KINETICS OF SORPTION OF FLUORIDE ON CALCINED MAGNESITE IN BATCH

    DEFF Research Database (Denmark)

    Singano, J. J.; Mashauri, D. A.; Mtalo, F. W.

    1997-01-01

    on first-order reaction with respect to the concentration of fluoride. The rate constant is directly proportional to the dosage. The model takes into accounts the lag time observed. The kinetical model can be described for any given dosage and initial fluoride concentration in the water. The reaction rate...... parameter, K, varies however slightly for different initial concentrations of fluoride in the water and different dosage of calcined magnesia. These relationships are described separately by two linear equations. It is discussed that the observed lag time is due to the fact that magnesia cannot remove...

  10. Fluoride gases damages on agricultural and ornamental plants

    Energy Technology Data Exchange (ETDEWEB)

    Grasso, V.; Padalino, O.

    1968-01-01

    Reports are presented concerning fluoride gases from a brick furnace, damaging agricultural and ornamental plants: Prunus armeniaca L. var. Reale d'Imola, Vitis vinifera L. var. Cardinal, Gladiolus spp., Pinus pinea L., Iris germanica L., that are particularly sensitive to these gases. There are descriptions of the morphological alterations and the authors have proven the presence of fluoride in the chemically analyzed samples. There is a list of plants found near the brick furnace that have been classified as (I) highly sensitive; (II) moderately sensitive; (III) very little sensitivity; (IV) immune to fluoride gases. 10 references, 9 figures.

  11. Nitrogen Trifluoride-Based Fluoride- Volatility Separations Process: Initial Studies

    Energy Technology Data Exchange (ETDEWEB)

    McNamara, Bruce K.; Scheele, Randall D.; Casella, Andrew M.; Kozelisky, Anne E.

    2011-09-28

    This document describes the results of our investigations on the potential use of nitrogen trifluoride as the fluorinating and oxidizing agent in fluoride volatility-based used nuclear fuel reprocessing. The conceptual process uses differences in reaction temperatures between nitrogen trifluoride and fuel constituents that produce volatile fluorides to achieve separations and recover valuable constituents. We provide results from our thermodynamic evaluations, thermo-analytical experiments, kinetic models, and provide a preliminary process flowsheet. The evaluations found that nitrogen trifluoride can effectively produce volatile fluorides at different temperatures dependent on the fuel constituent.

  12. Fluoride intake from meals served in daycare centres in municipalities with different fluoride concentrations in the water supply.

    Science.gov (United States)

    Pagliari Tiano, Ana Valéria; Moimaz, Suzely Adas Saliba; Saliba, Orlando; Saliba, Nemre Adas; Sumida, Dóris Hissako

    2009-01-01

    The aim of this study was (1) to determine the fluoride content in the meals served to children aged up to 36 months in daycare centres of two municipalities with different levels of fluoride in the water supply, (2) to calculate the mean fluoride ingested daily by the children when consuming those meals and (3) to analyse the contribution of this consumption to the development of dental fluorosis. Samples of the meals served to the children were collected during a whole week. The fluoride content of the samples of solid foods and milk was analysed using an ion-specific electrode combined with reference electrode after diffusion facilitated by hexamethyldisiloxane. Samples of beverages were buffered with an equal volume of total ionic strength adjustment buffer and analysed using a combined electrode. The results were compared using the Mann-Whitney test. Mean fluoride contents of the meals were of 0.204 +/- 0.179 and 0.322 +/- 0.242 microg F/mL (P 0.05). The children were not exposed to dental fluorosis in the daycare centres. However, the risk cannot be ignored, considering the meals and the use of fluoridated dentifrices at home may also contribute to fluoride intake.

  13. Crystallization of heavy metal fluoride glasses

    Science.gov (United States)

    Bansal, Narottam P.; Bruce, Allan J.; Doremus, R. H.; Moynihan, C. T.

    1984-01-01

    The kinetics of crystallization of a number of fluorozirconate glasses were studied using isothermal and dynamic differential scanning calorimetry and X-ray diffraction. The addition of the fluorides LiF, NaF, AlF3, LaF3 to a base glass composition of ZrF4-BaF2 reduced the tendency to crystallize, probably by modifying the viscosity-temperature relation. ZrF4-BaF2-LaF3-AlF3-NaF glass was the most stable against devitrification and perhaps is the best composition for optical fibers with low scattering loss. Some glasses first crystallize out into metastable beta-BaZr2F10 and beta-BaZrF6 phases, which transform into the most stable alpha-phases when heated to higher temperatures. The size of the crystallites was estimated to be about 600 A from X-ray diffraction.

  14. Electrocrystallisation of tantalum in molten fluoride media

    Energy Technology Data Exchange (ETDEWEB)

    Massot, L. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques et Materiaux, Universite Paul Sabatier, 118 route de Narbonne, 31062 Toulouse Cedex (France)]. E-mail: massot@chimie.ups-tlse.fr; Chamelot, P. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques et Materiaux, Universite Paul Sabatier, 118 route de Narbonne, 31062 Toulouse Cedex (France); Palau, P. [Pechiney CRV-UR GP, Parc Economique Centr' Alp, BP27, 38340 Voreppe (France); Taxil, P. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques et Materiaux, Universite Paul Sabatier, 118 route de Narbonne, 31062 Toulouse Cedex (France)

    2005-09-20

    The electrochemical nucleation of tantalum in molten alkaline fluoride media is investigated using chronoamperometry in the 670-750 deg C temperature range to optimize the operating conditions for preparing tantalum coatings for anode materials. Chronoamperometric results show that the electrodeposition process involves progressive nucleation with diffusion-controlled growth of the nuclei, which was confirmed by scanning electron microscopy. The influence of the temperature and the overpotential on the nucleation site densities is considered. Once the deposit has been obtained, plotting the roughness of the tantalum coatings as a function of the current densities reveals a minimum at about 80 mA/cm{sup 2}. This minimum is considered by the authors as a consequence of the progressive nucleation.

  15. Exraction and separation of CERIUM(IV/FLUORINE in fluoride-bearing cerium sulfate solution with fluoride coordination agent

    Directory of Open Access Journals (Sweden)

    Y. Li

    2014-07-01

    Full Text Available In this paper the extraction and separation of cerium/fluorine in fluoride-bearing cerium sulfate solution with fluoride coordination agent has been studied. The UV-vis spectra suggest that Zr6+ and Al3+ can scrub the F- from [CeF2] 2+ complex. The separation and conductivity studies show that aluminum salt is the most suitable fluoride coordination agent, and an ion-exchange reaction is involved between Ce4+/ [CeF2] 2+ and hydrogen ion.

  16. Comparison of Fluoride Levels in Tap and Bottled Water and Reported Use of Fluoride Supplementation in a United States?Mexico Border Community

    OpenAIRE

    Beamer, Paloma I.; Victory, Kerton R; Cabrera, Nolan L; Daniela Larson; Kelly A. Reynolds; Joyce Latura; Thomson, Cynthia A.

    2017-01-01

    Background Compared to the general United States (U.S.) population, Arizona counties along the U.S.–Mexico border have a higher prevalence of dental caries, which can be reduced with adequate fluoride exposure. Because of concern regarding local tap water quality, fluoride-free bottled water consumption is common in this region, raising concern that families are not receiving adequate fluoride to promote dental health. Objective To evaluate the levels of fluoride in tap and bottled...

  17. 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.

  18. Fluoride distribution in different environmental segments at Hirakud ...

    African Journals Online (AJOL)

    Administrator

    768019, Orissa, India. 2Rajib Gandhi National Fellow, India. 3Environment Engineer, NTPC, Kaniha, Talcher, Orissa, India. Accepted 10 August, 2009. Fluoride is a major pollutant originating from aluminium smelting polluting the air, water and ...

  19. Baltimore and the Beginnings of the Fluoride Controversy.

    Science.gov (United States)

    Daws, Steven

    2015-01-01

    The fluoridation of municipal water as a preventive dental health measure has proven to be a contentious issue from its very outset. In 1952, Baltimore became the first major city in the United States to artificially add fluoride to its water supply. This study draws largely on print media sources as a means of discerning public sentiment, in order to evaluate the nature of Baltimore's fluoride controversy in its infancy. Initial response was influenced by prior exposure to the substance within the context of dentistry, as well as a continued trend of conservatism within the community. Logistical issues during implementation due to the necessary upscale of established practices to accommodate Baltimore's population served to further exacerbate concerns. Much of the opposition was predicated on the breadth of the measure, as evidenced by the myriad of personal concerns put forth in objection. Personal concerns developed into demands for personal autonomy, providing a philosophical foundation for the anti-fluoridation movement that persists today.

  20. Fluoride-responsive organogelator based on oxalamide-derived anthraquinone.

    Science.gov (United States)

    Dzolić, Zoran; Cametti, Massimo; Dalla Cort, Antonella; Mandolini, Luigi; Zinić, Mladen

    2007-09-14

    Anthraquinone derived oxalamide gelator 1 forms with aromatic solvents and alcohols very stable gels which selectively respond to the presence of fluoride anion by colour change and/or gel-to-sol transition.

  1. Oral microflora in preschool children attending a fluoride varnish program

    DEFF Research Database (Denmark)

    Anderson, Maria; Grindefjord, Margaret; Dahllöf, Göran

    2016-01-01

    BACKGROUND: To compare the oral microflora in preschool children attending a fluoride varnish program with a reference group receiving a standard oral health program without fluoride varnish applications. A second aim was to relate the microbial composition to the caries prevalence. METHODS: Five...... hundred seven 3-year-old children were enrolled from a cohort of 3403 preschool children taking part in a community based oral health project. Two hundred sixty-three of them had attended caries-preventive program with semi-annual applications of a fluoride varnish since the age of 1 year (test group......-annual fluoride varnish applications did not seem to significantly influence the oral microflora in preschool children. TRIAL REGISTRATION: www.controlled-trials.com (ISRCTN35086887) 20131216 'retrospectively registered'....

  2. Visual sensing of fluoride ions by dipyrrolyl derivatives bearing ...

    Indian Academy of Sciences (India)

    withdrawing quinone or dicyano functionalities in their architecture permit the detection of fluoride ions under visual (naked-eye) as well as optical (absorption and fluorescence) and electrochemical conditions in organic solvents.

  3. Fluoride-assisted synthesis of bimodal microporous SSZ-13 zeolite

    NARCIS (Netherlands)

    Zhu, Xiaochun; Kosinov, Nikolay; Hofmann, Jan P.; Mezari, Brahim; Qian, Qingyun; Rohling, Roderigh; Weckhuysen, Bert M.; Ruiz-Martinez, Javier; Hensen, Emiel J. M.

    The presence of small amount of fluoride in alkaline hydrothermal synthesis of SSZ-13 zeolite yields bimodal microporous particles with substantially improved performance in the methanol-to-olefins (MTO) reaction. Hydrocarbon uptake measurements and fluorescence microspectroscopy of spent catalysts

  4. Toxic fluoride gas emissions from lithium-ion battery fires.

    Science.gov (United States)

    Larsson, Fredrik; Andersson, Petra; Blomqvist, Per; Mellander, Bengt-Erik

    2017-08-30

    Lithium-ion battery fires generate intense heat and considerable amounts of gas and smoke. Although the emission of toxic gases can be a larger threat than the heat, the knowledge of such emissions is limited. This paper presents quantitative measurements of heat release and fluoride gas emissions during battery fires for seven different types of commercial lithium-ion batteries. The results have been validated using two independent measurement techniques and show that large amounts of hydrogen fluoride (HF) may be generated, ranging between 20 and 200 mg/Wh of nominal battery energy capacity. In addition, 15-22 mg/Wh of another potentially toxic gas, phosphoryl fluoride (POF3), was measured in some of the fire tests. Gas emissions when using water mist as extinguishing agent were also investigated. Fluoride gas emission can pose a serious toxic threat and the results are crucial findings for risk assessment and management, especially for large Li-ion battery packs.

  5. Readying Community Water Fluoridation Advocates through Training, Surveillance, and Empowerment.

    Science.gov (United States)

    Veschusio, C; Jones, M K; Mercer, J; Martin, A B

    2017-11-10

    This paper describes the Community Water Fluoridation Advocacy Training Project that was designed to develop networks of community water fluoridation advocates in rural communities. The South Carolina (SC) Department of Health and Environmental Control Division of Oral Health staff and the SC Dental Association were responsible for developing and facilitating the training sessions for key policy influencers, which included medical and dental providers, early childhood educators, and water system operators and managers. Findings from the post-training survey indicate that participants increased their knowledge and skills to discuss the impact of water fluoridation on the dental health of community residents. Participants identified a need for online access to water fluoridation education and advocacy materials. Dental public health competencies illustrated: communication and collaboration with groups and individuals, and advocate, implement and evaluate public health policy, legislation and regulations. Copyright© 2017 Dennis Barber Ltd.

  6. Study of fluoride in polluted and unpolluted estuarine environments

    Digital Repository Service at National Institute of Oceanography (India)

    Zingde, M.D.; Mandalia, A.V.

    estuary, significant deviation from the theoretical dilution line (TDL) in the chlorinity range 0.5-8ppt was observed in Mindhola River estuary due to the externally added fluoride which largely remained in solution. The excess of fluroide over...

  7. Graphite fluoride as a solid lubricant in a polyimide binder

    Science.gov (United States)

    Fusaro, R. L.; Sliney, H. E.

    1972-01-01

    Polyimide resin (PI) was shown to be a suitable binder material for the solid lubricant graphite fluoride, (CF(1.1))n. Comparisons were made to similar tests using PI-bonded MOS2 films, graphite fluoride rubbed films, and MOS2 rubbed films. The results showed that, at any one specific temperature between 25 and 400 C, the wear life of PI-bonded graphite fluoride films exceeded those of the other three films by at least a factor of 2 and by as much as a factor of 60. Minimum friction coefficients for the PI-bonded films were 0.08 for graphite fluoride and 0.04 for MOS2. The rider wear rates for the two PI-bonded films at 25 C were nearly equal.

  8. Ratiometric fluorescence signalling of fluoride ions by an ...

    Indian Academy of Sciences (India)

    ... Lecture Workshops · Refresher Courses · Symposia. Home; Journals; Journal of Chemical Sciences; Volume 119; Issue 2. Ratiometric fluorescence signalling of fluoride ions by an amidophthalimide derivative. Moloy Sarkar Raghavendra Yellampalli Bhaswati Bhattacharya Ravi Kumar Kanaparthi Anunay Samanta.

  9. Latest developments in non-fluoridated remineralizing technologies.

    Science.gov (United States)

    Goswami, M; Saha, S; Chaitra, T R

    2012-01-01

    The goal of modern dentistry is to manage non-cavitated carious lesions non-invasively through remineralization in an attempt to prevent disease progression, and to improve strength, esthetics, and function of teeth. The emphasis currently is being given to new technologies for enamel remineralization which suggest the changes in the understanding of dental caries. The aim of this paper is to review the contemporary non-fluoridated systems available for remineralization therapy and ideas for their implementation into clinical practice. A search of articles from "Pubmed" and "Medline" with the keywords Remineralization-demineralization, Casein derivatives, Non-fluoridated remineralizing agents was conducted. A total of 526 abstracts were collected, out of which 172 articles that discussed current technologies of non-fluoridated remineralizing agents were read and 33 most relevant articles were included in this paper. Casein phosphopeptide based technology has been established as a strong non-fluoridated remineralizing agent fulfilling all the criteria of an ideal remineralizing material.

  10. Fluoride supplementation. A survey of pediatricians and pediatric dentists.

    Science.gov (United States)

    Jones, K F; Berg, J H

    1992-12-01

    To determine the protocol and use of prescriptions of fluoride supplementation by primary care pediatricians and pediatric dentists in the Houston (Tex) area. Survey mailed to all primary care pediatricians and pediatric dentists listed in the Yellow Pages of the Greater Houston telephone directory. 153 pediatricians and 47 pediatric dentists. Ninety-six percent of the participants prescribed fluoride supplements. Fifty-one percent of the pediatricians and 61% of the dentists considered that the fluoride content of the water was important. Seventy percent of the pediatricians and 30% of the dentists discontinued the use of supplements by age 7 to 10 years. Pediatricians and pediatric dentists should consider the need for water analysis prior to supplementation and should continue the use of fluoride supplements until 16 years of age.

  11. Fluoride sensing by catechol-based π-electron systems.

    Science.gov (United States)

    An, Byeong-Kwan; Wang, Xin; Burn, Paul L; Meredith, Paul

    2010-11-15

    We have developed new catechol-based sensors that can detect fluoride via fluorescence or optical absorption even in the presence of other halides. The level and sensitivity of detection of the sensing molecules is dependent on the chromophore length, which is controlled by the number of thiophene units (one to three) within the chromophore. The sensor with three thiophene units, (E)-2-(2,2'-terthiophen-5-yl)-3-(3,4-dihydroxyphenyl)acrylonitrile, gives the best response to fluoride. By using fluorescence measurements fluoride is detectable over the concentration range 1.7 μM to 200 μM. Importantly, when adsorbed onto a solid support the fluorescent catechol dye can be used to detect the presence of fluoride in aqueous solution.

  12. Fluoride removal from water by zirconium (IV) doped chitosan bio ...

    African Journals Online (AJOL)

    Toshiba

    sorbents for defluoridation below stringent level 1.5 mg/L, displayed low to moderate adsorption capacity at ... of the fluorides bearing minerals are associated with the rocks of ... chemical processing, aluminum making, electroplating also act ...

  13. Water fluoridation for the prevention of dental caries.

    Science.gov (United States)

    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

  14. Fluoride removal from aqueous solution by pumice: case study on ...

    African Journals Online (AJOL)

    EJIRO

    The effect of pH, contact time, fluoride concentration and adsorbent dose on the fluoride sequestration was investigated. The optimum ... adsorbent (Crittenden et al., 2005; Malakootian et al.,. 2008; Malakootian et al., 2009). ... by dissolving NaF salt (2.21 g) in distillated water (1000 mL). HCL and NaOH 0.1 N were used in ...

  15. Preparation and Characterization of Rare Earth Doped Fluoride Nanoparticles

    OpenAIRE

    DeVol, Timothy A.; Basak Yazgan-Kukouz; Baris Kokuoz; DiMaio, Jeffrey R.; Sprinkle, Kevin B.; Tiffany L. James; Courtney J. Kucera; Luiz G. Jacobsohn; John Ballato

    2010-01-01

    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 luminesc...

  16. Crystallization, Optical and Chemical Properties of Fluoride Glasses

    Science.gov (United States)

    Doremus, R. H.

    1985-01-01

    Fluoride glasses have great promise as infrared optical components, especially fibers, because they are transparent to 8 micrometers and higher. In order to optimize properties, different glass compositions are needed. Some are hard to form in a container, and may possibly be formable in a containerless furnace. Understanding of crystallization with and without a container could lead to glasses with optimum properties. Chemical durability (attack by water) can limit or extend the applicability of fluoride glasses. Progress to date is given.

  17. A comparative study of fluoride release from two different sealants

    OpenAIRE

    Ananda, SR.; H Mythri

    2014-01-01

    Objectives: The introduction of fluoride releasing sealants and glass ionomer cements as fissure sealants adds another dimension to prevention of pit and fissure caries. The ability of resin sealants and glass ionomer cements to release fluoride on a long term basis to the sealed enamel and the adjacent unsealed pit and fissure and cuspal in - cline enamel may allow for further reduction in pit and fissure caries experience for children. Hence, the study was conducted to compar...

  18. A comparative study of fluoride release from two different sealants

    OpenAIRE

    Ananda, Shimoga-Raju; Mythri, Halappa

    2014-01-01

    Objectives: The introduction of fluoride releasing sealants and glass ionomer cements as fissure sealants adds another dimension to prevention of pit and fissure caries. The ability of resin sealants and glass ionomer cements to release fluoride on a long term basis to the sealed enamel and the adjacent unsealed pit and fissure and cuspal incline enamel may allow for further reduction in pit and fissure caries experience for children. Hence, the study was conducted to compare the amount of fl...

  19. Fluoride levels in commercial dentifrices and drinking Water in Algeria

    OpenAIRE

    MERGHACHE, D.; BELLOUT, B.; MERGHACHE, S.; BOUCHERIT-ATMANI, Z.

    2011-01-01

    More and more scientific evidence show that fluorides have a cariostatic action to the plaque-saliva-tooth interface during cariogenous dissolution. Fluorides slow down demineralization and enhance remineralization. Their action is optimal, in the oral environment, when used at low concentrations on a continuous basis. The use of the fluorinated toothpastes during brushing of the teeth is a simple, rational method of daily topics application of fluorine, largely used in the context of prevent...

  20. Developmental fluoride neurotoxicity: a systematic review and meta-analysis.

    Science.gov (United States)

    Choi, Anna L; Sun, Guifan; Zhang, Ying; Grandjean, Philippe

    2012-10-01

    Although fluoride may cause neurotoxicity in animal models and acute fluoride poisoning causes neurotoxicity in adults, very little is known of its effects on children's neurodevelopment. We performed a systematic review and meta-analysis of published studies to investigate the effects of increased fluoride exposure and delayed neurobehavioral development. We searched the MEDLINE, EMBASE, Water Resources Abstracts, and TOXNET databases through 2011 for eligible studies. We also searched the China National Knowledge Infrastructure (CNKI) database, because many studies on fluoride neurotoxicity have been published in Chinese journals only. In total, we identified 27 eligible epidemiological studies with high and reference exposures, end points of IQ scores, or related cognitive function measures with means and variances for the two exposure groups. Using random-effects models, we estimated the standardized mean difference between exposed and reference groups across all studies. We conducted sensitivity analyses restricted to studies using the same outcome assessment and having drinking-water fluoride as the only exposure. We performed the Cochran test for heterogeneity between studies, Begg's funnel plot, and Egger test to assess publication bias, and conducted meta-regressions to explore sources of variation in mean differences among the studies. The standardized weighted mean difference in IQ score between exposed and reference populations was -0.45 (95% confidence interval: -0.56, -0.35) using a random-effects model. Thus, children in high-fluoride areas had significantly lower IQ scores than those who lived in low-fluoride areas. Subgroup and sensitivity analyses also indicated inverse associations, although the substantial heterogeneity did not appear to decrease. The results support the possibility of an adverse effect of high fluoride exposure on children's neurodevelopment. Future research should include detailed individual-level information on prenatal

  1. Systemic effect of water fluoridation on dental caries prevalence.

    Science.gov (United States)

    Cho, Hyun-Jae; Jin, Bo-Hyoung; Park, Deok-Young; Jung, Se-Hwan; Lee, Heung-Soo; Paik, Dai-Il; Bae, Kwang-Hak

    2014-08-01

    The aim of this study was to evaluate the systemic effect of water fluoridation on dental caries prevalence and experience in Cheongju, South Korea, where water fluoridation ceased 7 years previously. A cross-sectional survey was employed at two schools where water fluoridation had ceased (WF-ceased area) and at two schools where the water had never been fluoridated (non-WF area). The schools in the non-WF area were of a similar population size to the schools in the WF-ceased area. Children of three age groups were examined in both areas: aged 6 (n = 505), 8 (n = 513), and 11 years (n = 467). The differences in the mean number of decayed or filled primary teeth (dft) and the mean number of decayed, missing, or filled permanent teeth (DMFT) scores between areas after adjusting for oral health behaviors and socio-demographic factors were analyzed by a Poisson regression model. The regression model showed that the DMFT ratio for children aged 11 years in the WF-ceased area was 0.581 (95% CI 0.450-0.751). In contrast, the dft ratio for age 6 in the WF-ceased area was 1.158 (95% CI 1.004-1.335). Only the DMFT ratio for age 8 (0.924, 95% CI 0.625-1.368) was not significant. While 6-year-old children who had not ingested fluoridated water showed higher dft in the WF-ceased area than in the non-WF area, 11-year-old children in the WF-ceased area who had ingested fluoridated water for approximately 4 years after birth showed significantly lower DMFT than those in the non-WF area. This suggests that the systemic effect of fluoride intake through water fluoridation could be important for the prevention of dental caries. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Fluoride Concentration in Drinking Water Resources; North of Iran

    Directory of Open Access Journals (Sweden)

    Amouei A.I. PhD,

    2016-03-01

    Full Text Available Aims Fluoride is one of the anions present in soil and water, and determining its level in drinking water is vital for preventing dental and bone diseases in societies. This research aimed to determine fluoride concentrations in drinking water sources of rural and urban areas of Babol City, Iran. Instrument & Methods This descriptive cross-sectional study was conducted in Babol City, Iran, in 2014. 384 water samples were taken from 43 wells and 3 springs in the rural areas, and from 20 wells, 3 water reservoirs, and the water distribution system in the urban areas. Fluoride concentrations of water samples were measured with a model DR2000 spectrophotometer using the standard SPADNS method. Data were entered to SPSS 16 software and were analyzed by ANOVA test. Findings The mean fluoride concentrations in the water samples of the deep wells were higher compared to those of the springs (p=0.01. The mean fluoride concentrations in the plains areas were higher compared to the mountainous regions (p=0.02. The mean fluoride concentrations in the wells of the urban areas, in the urban reservoirs, and in the urban water distribution system were 0.40±0.14, 0.39±0.15, and 0.40±0.15mg/l, respectively (p=0.07. Fluoride concentrations in water in urban areas during various seasons varied from 0.31 to 0.45mg/l (p=0.06. Conclusion Fluoride concentrations in all drinking water sources in urban and rural areas of Babol are less than the ranges recommended by WHO and Iranian national standards.

  3. Combinatorial Effects of Arginine and Fluoride on Oral Bacteria

    Science.gov (United States)

    Zheng, X.; Cheng, X.; Wang, L.; Qiu, W.; Wang, S.; Zhou, Y.; Li, M.; Li, Y.; Cheng, L.; Li, J.; Zhou, X.

    2015-01-01

    Dental caries is closely associated with the microbial disequilibrium between acidogenic/aciduric pathogens and alkali-generating commensal residents within the dental plaque. Fluoride is a widely used anticaries agent, which promotes tooth hard-tissue remineralization and suppresses bacterial activities. Recent clinical trials have shown that oral hygiene products containing both fluoride and arginine possess a greater anticaries effect compared with those containing fluoride alone, indicating synergy between fluoride and arginine in caries management. Here, we hypothesize that arginine may augment the ecological benefit of fluoride by enriching alkali-generating bacteria in the plaque biofilm and thus synergizes with fluoride in controlling dental caries. Specifically, we assessed the combinatory effects of NaF/arginine on planktonic and biofilm cultures of Streptococcus mutans, Streptococcus sanguinis, and Porphyromonas gingivalis with checkerboard microdilution assays. The optimal NaF/arginine combinations were selected, and their combinatory effects on microbial composition were further examined in single-, dual-, and 3-species biofilm using bacterial species–specific fluorescence in situ hybridization and quantitative polymerase chain reaction. We found that arginine synergized with fluoride in suppressing acidogenic S. mutans in both planktonic and biofilm cultures. In addition, the NaF/arginine combination synergistically reduced S. mutans but enriched S. sanguinis within the multispecies biofilms. More importantly, the optimal combination of NaF/arginine maintained a “streptococcal pressure” against the potential growth of oral anaerobe P. gingivalis within the alkalized biofilm. Taken together, we conclude that the combinatory application of fluoride and arginine has a potential synergistic effect in maintaining a healthy oral microbial equilibrium and thus represents a promising ecological approach to caries management. PMID:25477312

  4. Determination of Fluoride in Organic and Non-organic Wines.

    Science.gov (United States)

    Paz, Soraya; Jaudenes, Juan Ramón; Gutiérrez, Angel José; Rubio, Carmen; Hardisson, Arturo; Revert, Consuelo

    2017-07-01

    Fluorine is an element of great importance to human health, as it is considered to be an essential element. However, both a deficiency and an excess, it can cause various problems. It is for this reason that values have been established regarding the recommended daily intake (RDI) and acceptable daily intake (ADI). The largest source of incorporation of fluoride is water, but it can be found in other foods and beverages, such as vegetables, tea, and wine. The aim of the study was to establish the fluoride concentration in organic and non-organic wines from different appellations of origin of the Canary Islands and mainland Spain, in order to assess the contribution of fluoride and toxic risk. A total of 53 samples of red, white, and rosé wines, both organic and non-organic, from different appellations of origin were analyzed. They were analyzed by potentiometric determination with ion-selective electrode for fluoride using the method of standard addition. The wines analyzed are within the recommended limits set by the International Organisation of Vine and Wine. RDI is not exceeded for adults, taking into account the data provided by the Spanish Agency for Consumer Affairs, Food Safety and Nutrition on the average consumption of "table wines" in Spain. Fluoride intake from wine poses no risk to the health of adults. The fluoride concentration of organic and non-organic wines is within the range of 0.03 to 0.70 mg/L.

  5. Risk assessment of fluoride exposure in drinking water of Tunisia.

    Science.gov (United States)

    Guissouma, Wiem; Hakami, Othman; Al-Rajab, Abdul Jabbar; Tarhouni, Jamila

    2017-06-01

    The presence of fluoride in drinking water is known to reduce dental cavities among consumers, but an excessive intake of this anion might leads to dental and skeletal fluorosis. This study reports a complete survey of the fluoridated tap water taken from 100 water consumption points in Tunisia. The fluoride concentrations in tap water were between 0 and 2.4 mg L(-1). Risk assessment of Fluoride exposure was assessed depending on the age of consumers using a four-step method: hazard identification, toxicity reference values selection (TRVs), daily exposure assessment, and risk characterization. Our findings suggest that approximately 75% of the Tunisian population is at risk for dental decay, 25% have a potential dental fluorosis risk, and 20% might have a skeletal fluorosis risk according to the limits of fluoride in drinking water recommended by WHO. More investigations are recommended to assess the exposure risk of fluoride in other sources of drinking water such as bottled water. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Fluoride and aluminum in teas and tea-based beverages

    Directory of Open Access Journals (Sweden)

    Hayacibara Mitsue Fujimaki

    2004-01-01

    Full Text Available OBJECTIVE: To evaluate fluoride and aluminum concentration in herbal, black, ready-to-drink, and imported teas available in Brazil considering the risks fluoride and aluminum pose to oral and general health, respectively. METHODS: One-hundred and seventy-seven samples of herbal and black tea, 11 types of imported tea and 21 samples of ready-to-drink tea were divided into four groups: I-herbal tea; II-Brazilian black tea (Camellia sinensis; III-imported tea (Camellia sinensis; IV-ready-to-drink tea-based beverages. Fluoride and aluminum were analyzed using ion-selective electrode and atomic absorption, respectively. RESULTS: Fluoride and aluminum levels in herbal teas were very low, but high amounts were found in black and ready-to-drink teas. Aluminum found in all samples analyzed can be considered safe to general health. However, considering 0.07 mg F/kg/day as the upper limit of fluoride intake with regard to undesirable dental fluorosis, some teas exceed the daily intake limit for children. CONCLUSIONS: Brazilian and imported teas made from Camellia sinensis as well as some tea-based beverages are sources of significant amounts of fluoride, and their intake may increase the risk of developing dental fluorosis.

  7. Response of grapevines to fluoride under field conditions

    Energy Technology Data Exchange (ETDEWEB)

    Murray, F.

    1983-07-01

    Grapevines (Vitis vinifera L. cv. Shiraz) were fumigated in open-top chambers with hydrogen fluoride for 64 days at mean atmospheric fluoride concentrations of 0.17 or 0.28 ..mu..gHFm/sup -3/. Other grapevines grown under ambient conditions in the vineyard or maintained in control chambers were exposed to 0.13 or 0.05 ..mu..gHFm/sup -3/, respectively. Leaves of grapevines exposed to 0.28, 0.17, 0.13, or 0.05 ..mu..gHFm/sup -3/ accumulated up to 85, 55, 20, or 11 ..mu..gFg/sup -1/, respectively. Foliar necrosis was observed on plants exposed to 0.28 ..mu..gHFm/sup -3/, but no injury symptoms were observed at 0.17 ..mu..gHFm/sup -3/ or in control plants. Grapevines growing under ambient conditions had significantly greater mean bunch weight, peduncle weight, number of grapes per bunch, and leaf protein levels than the fumigated treatments. However, these differences may be associated with a chamber effect rather than with an effect of fluoride on grapevines. No significant differences were found between treatments for grape potential alcohol content, fruit acids, number of bunches or grapes per vine, fresh weight of grapes, or leaf chlorophyll content, despite foliar fluoride concentrations in the highest fluoride fumigation level reaching 85 ..mu..gFg/sup -1/. No evidence was found of significant fluoride accumulation in berries or canes. 26 references, 4 tables.

  8. Comparison of in vitro fluoride uptake from whitening toothpastes and a conventional toothpaste in demineralised enamel.

    Science.gov (United States)

    Altenburger, Markus J; Bernhart, Jasmin; Schicha, Thurid D; Wrbas, Karl-Thomas; Hellwig, Elmar

    2010-01-01

    Studies on the compatibility of abrasives and fluoride compounds deal exclusively with fluoride uptake and remineralization after storing the enamel specimens in a toothpaste-saliva mixture. The influence of brushing on the fluoride uptake when highly abrasive toothpastes are used has hardly been investigated so far. The aim of the present study was to investigate fluoride uptake in initially demineralised dental enamel after storage in, or brushing with, whitening toothpaste slurries, compared to a conventional toothpaste. For this purpose two widely available whitening toothpastes with ionically bound fluoride (sodium fluoride NaF), two with covalently-bound fluoride toothpastes (sodium monofluorophosphate, NaMFP) and a conventional amine fluoride toothpaste (AmF) were compared. The fluoride uptake after use of the AmF toothpaste was shown to be statistically significantly higher than that after application of the NaF toothpastes, which in turn was statistically significantly higher than the uptake resulting from NaMFP application. The fluoride uptake was slightly higher when the enamel samples were brushed with NaF toothpaste, rather than just stored in the respective toothpaste slurry. Brushing with highly abrasive toothpastes did not negatively influence fluoride uptake in demineralised dental enamel. The ionic form of the fluoride in toothpastes appears to be critical for increased fluoride uptake. The acidic components of the AmF toothpaste improved fluoride uptake compared to alkaline NaF toothpastes.

  9. The history of public health use of fluorides in caries prevention.

    Science.gov (United States)

    Šket, Tea; Kukec, Andreja; Kosem, Rok; Artnik, Barbara

    2017-06-01

    The aim of our study was to chronologically analyse various public health measures of fluoride use in caries prevention. We systematically searched the PubMed database on the preventive role of fluorides in public health, published from 1984 to 2014. The search process was divided into four steps, where inclusion and exclusion criteria were defined. Qualitative methodology was used for the article analysis. In the research process, the described forms of F use, diversity of the described F agents, and the observed population group were analysed. In our systematic review, 40 relevant reviews were revealed. Fluorides have been used in many different forms, but only a few studies showed their significant role in public health. Water fluoridation was the most important public health measure. In the recent decades, the number of studies on topical fluorides is constantly rising. The most extensively described topical forms of fluorides are professionally applied fluoride agents and fluoride toothpaste for home-use. The use of fluoride containing toothpaste in caries prevention is a safe and successful public health measure (PHM) if their use is widespread, and it is recommended for all. The results on other topical forms of fluorides are insufficient to be suggested as an important PHM. The role of fluorides in public health prevention has changed in accordance with the knowledge about the fluoride cariostatic mechanism. Previously the most important pre-eruptive effect of fluorides was supplemented by the post eruptive effect. Abundant evidence exists to show the effectiveness of systemic and topical fluorides.

  10. Thallium in spawn, juveniles, and adult common toads (Bufo bufo) living in the vicinity of a zinc-mining complex, Poland

    OpenAIRE

    Dmowski, Krzysztof; Rossa, Monika; Kowalska, Joanna; Krasnodębska-Ostręga, Beata

    2014-01-01

    A breeding population of the common toad Bufo bufo living in the vicinity of a Zn-Pb smelting works in Bukowno, Poland was studied for the presence of thallium. Tl concentration was measured in the bottom sediments of the spawning pond, in the laid eggs, in juveniles after metamorphosis, and in the selected tissues of the adult individuals. A very high concentration of Tl was detected in the spawn (13.97 ± 8.90 mg/kg d.w.). In 50 % of the spawn samples, levels exceeded 20 mgTl/kg d.w. The iss...

  11. SIMILAR 1-YEAR CARIES INCREMENT AFTER USE OF FLUORIDE OR NON-FLUORIDE TOOTHPASTE IN INFANTS AND TODDLERS

    National Research Council Canada - National Science Library

    Palinee Detsomboonrat; Chutima Trairatvorakul; Pagaporn Pantuwadee Pisarnturakit

    2016-01-01

    Although 1000 ppm fluoride (F) toothpaste is recommended for all age groups, many parents still choose 500 ppm F or non-F toothpaste for their toddlers to avoid the possibility of an excessive intake of F...

  12. Effects of potassium channel opener on the kinetics of thallium-201 in in-vitro and in-vivo

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J.; Kim, E. J.; Ahn, B. C.; Chae, S. C.; Lee, K. B. [College of Medicine, Kyungpook National Univ., Taegu (Korea, Republic of); Kim, C. K. [Mt. Sinai Medical School, New York (United States)

    1997-07-01

    Potassium channel opener (K-opener) opens membrane ATP-sensitive K{sup +}-channel and induces and increase in potassium efflux from cells. K-openers are powerful smooth muscle relaxants and currently used as antihypertensive, antianginal drugs or bronchodilators in clinic. Pharmacologic potency of newly synthesized K-opener is being evaluated with efflux capacity of preincubated Rb-83 from the isolated aortic vascular tissue preparation. Thallium has similar characteristics to those of rubidium and potassium in vivo. To evaluate the effect of pinacidil (a potent K-opener) on Tl-201 biokinetics, we have performed uptake/washout studies in cultured myocytes, and mice biodistribution study. Primary culture of spontaneous contracting myocytes was undertake from hearts of newborn Sprague-Dawley rat. Different concentration of pinacidil (100nM or 10uM) was co-incubated with Tl-201 in HBSS buffer to evaluate its effect on cellular uptake, or challenged to myocyte preparations pre-incubated with Tl-201 for washout study. Pinacidil was injected into mice simultaneous or 10-min after Tl-201 injection, and organ uptake and whole body retention ratio was measured using gamma counter or dose calibrator. Co-incubation of pinacidil with Tl-201 resulted in a decrease in Tl uptake into myocytes by 1.6 - 2.5 times, and an increase in washout by 1.6 - 3.1 times. Pinacidil injection resulted in mild decrease in blood, heart and liver uptake in mice, bur renal uptake was markedly decreased in a dose dependent manner. These results suggest that the pinacidil Tl-201 kinetics and may potentially affect the interpretation of Tl-201 myocardial imaging.

  13. Functional Significance of Angiographic Collaterals in Patients with Totally Occluded Right Coronary Artery: Intracoronary Thallium-201 Scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Do Yun; Lee, Jong Doo; Cho, Seung Yun; Shim, Won Heum; Ha, Jong Won; Kim, Han Soo; Kwon, Hyuk Moon; Jang, Yang Soo; Chung, Nam Sik; Kim, Sung Soon [Yonsei University College of Medicine, Seoul (Korea, Republic of); Park, Chang Yun; Kim, Young Soo [Inje University College of Medicine, Seoul (Korea, Republic of)

    1993-07-15

    To compare the myocardial viability in patients suffering from total occlusion of the right coronary artery (RCA) with the angiographic collaterals, intracoronary injection of Thallium-201 (T1-201) was done to 14 coronary artery disease (CAD) patients (pts) with total occlusion of RCA and into four normal subjects for control. All 14 CAD pts had Grade 2 or 3 collateral circulations. There were 14 male and 4 females, and their ages ranged from 31 to 70 years. In nine pts, T1-201 was injected into left main coronary artery (LCA) (300 approx 350 mu Ci) to evaluate the myocardial viability of RCA territory through collateral circulations. The remaining five pts received T1-201 into RCA (200-250 mu Ci) because two had intraarterial bridging collaterals and three had previous successful PTCA. Planar and SPECT myocardial perfusion images were obtained 30 minutes, and four to five hours after T1-201 reinjection. Intravenous T1-201 reinjection (six pts) or {sup 99m}Tc-MIBI (two pts) were also performed in eight CAD pts. Intracoronary myocardial perfusion images were compared with intravenous T1-201(IV T1-201) images, EGG, and ventriculography. Intracoronary TI-201 images proved to be superior to that of IV T1-201 due to better myocardial to background uptake ratio and more effective in the detection of viable tissue. We also found that perfusion defects were smaller on intracoronary T1-201 images than those on the IV T1-201. All of the 14 CAD pts had either mostly viable myocardium (seven pts) or large area of T1-201 perfusion (seven pts) in RCA territory, however ventriculographic wall motion and ECG did not correlate well with intracoronary myocardial perfusion images. In conclusion, total RCA occlusion patients with well developed collateral circulation had large area of viable myocardial in the corresponding territory.

  14. Disease stage classification in hypertrophic cardiomyopathy by dual analysis of iodine-123-labeled metaiodobenzylguanidine and thallium-201 myocardial scintigraphies

    Energy Technology Data Exchange (ETDEWEB)

    Hiasa, Go [Ehime Univ., Matsuyama (Japan). School of Medicine

    2001-08-01

    Many patients with hypertrophic cardiomyopathy (HCM) gradually changes from typical myocardial hypertrophy to dilated cardiomyopathy-like features. However, it is difficult to estimate the disease stage in HCM. To determine the disease stage, dual analysis of iodine-123-labeled metaiodobenzylguanidine ({sup 123}I-MIBG) and thallium-201 ({sup 201}Tl) myocardial scintigraphies were performed in 108 HCM patients. According to the scintigraphic distribution patterns, patients were divided into three groups. Group A (n=15): normal distributions of both {sup 123}I-MIBG and {sup 201}Tl, group B (n=71): normal {sup 201}Tl and low {sup 123}I-MIBG patterns, group C (n=22): low distributions of both scintigraphies. The decrease in {sup 201}Tl uptake was observed in only group C. Concerning {sup 123}I-MIBG, heart-to-mediastinum ratio (H/M) and washout rate (WOR) had good correlations with left ventricular systolic functions. H/M was decreased and WOR was increased in order of C, B and A groups. Left ventricular diastolic function reflected by isovolumic relaxation time was longer in group B than in group A. Attenuated left ventricular hypertrophy, enlarged left ventricular volumes, impaired left ventricular functions and serious clinical symptoms were observed in only group C. Myocardial sympathetic abnormalities in group B may be mainly due to myocardial hypertrophy, and those in group C may be due to myocardial injury. Dual analysis of {sup 123}I-MIBG and {sup 201}Tl scintigraphies may be useful to classify disease stages of HCM. (author)

  15. New quaternary thallium indium germanium selenide TlInGe2Se6: Crystal and electronic structure

    Science.gov (United States)

    Khyzhun, O. Y.; Parasyuk, O. V.; Tsisar, O. V.; Piskach, L. V.; Myronchuk, G. L.; Levytskyy, V. O.; Babizhetskyy, V. S.

    2017-10-01

    Crystal structure of a novel quaternary thallium indium germanium selenide TlInGe2Se6 was investigated by means of powder X-ray diffraction method. It was determined that the compound crystallizes in the trigonal space group R3 with the unit cell parameters a = 10.1798(2) Å, c = 9.2872(3) Å. The relationship with similar structures was discussed. The as-synthesized TlInGe2Se6 ingot was tested with X-ray photoelectron spectroscopy (XPS) and X-ray emission spectroscopy (XES). In particular, the XPS valence-band and core-level spectra were recorded for initial and Ar+ ion-bombarded surfaces of the sample under consideration. The XPS data allow for statement that the TlInGe2Se6 surface is rigid with respect to Ar+ ion-bombardment. Particularly, Ar+ ion-bombardment (3.0 keV, 5 min duration, ion current density fixed at 14 μA/cm2) did not cause substantial modifications of stoichiometry in topmost surface layers. Furthermore, comparison on a common energy scale of the XES Se Kβ2 and Ge Kβ2 bands and the XPS valence-band spectrum reveals that the principal contributions of the Se 4p and Ge 4p states occur in the upper and central portions of the valence band of TlInGe2Se6, respectively, with also their substantial contributions in other portions of the band. The bandgap energy of TlInGe2Se6 at the level of αg=103 cm-1 is equal to 2.38 eV at room temperature.

  16. High Temperature Fluoride Salt Test Loop

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, Adam M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cunningham, Richard Burns [Univ. of Tennessee, Knoxville, TN (United States); Fugate, David L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holcomb, David Eugene [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kisner, Roger A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Peretz, Fred J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Robb, Kevin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wilson, Dane F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yoder, Jr, Graydon L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-12-01

    Effective high-temperature thermal energy exchange and delivery at temperatures over 600°C has the potential of significant impact by reducing both the capital and operating cost of energy conversion and transport systems. It is one of the key technologies necessary for efficient hydrogen production and could potentially enhance efficiencies of high-temperature solar systems. Today, there are no standard commercially available high-performance heat transfer fluids above 600°C. High pressures associated with water and gaseous coolants (such as helium) at elevated temperatures impose limiting design conditions for the materials in most energy systems. Liquid salts offer high-temperature capabilities at low vapor pressures, good heat transport properties, and reasonable costs and are therefore leading candidate fluids for next-generation energy production. Liquid-fluoride-salt-cooled, graphite-moderated reactors, referred to as Fluoride Salt Reactors (FHRs), are specifically designed to exploit the excellent heat transfer properties of liquid fluoride salts while maximizing their thermal efficiency and minimizing cost. The FHR s outstanding heat transfer properties, combined with its fully passive safety, make this reactor the most technologically desirable nuclear power reactor class for next-generation energy production. Multiple FHR designs are presently being considered. These range from the Pebble Bed Advanced High Temperature Reactor (PB-AHTR) [1] design originally developed by UC-Berkeley to the Small Advanced High-Temperature Reactor (SmAHTR) and the large scale FHR both being developed at ORNL [2]. The value of high-temperature, molten-salt-cooled reactors is also recognized internationally, and Czechoslovakia, France, India, and China all have salt-cooled reactor development under way. The liquid salt experiment presently being developed uses the PB-AHTR as its focus. One core design of the PB-AHTR features multiple 20 cm diameter, 3.2 m long fuel channels

  17. Formation of Fluorohydroxyapatite with Silver Diamine Fluoride.

    Science.gov (United States)

    Mei, M L; Nudelman, F; Marzec, B; Walker, J M; Lo, E C M; Walls, A W; Chu, C H

    2017-09-01

    Silver diamine fluoride (SDF) is found to promote remineralization and harden the carious lesion. Hydroxyapatite crystallization is a crucial process in remineralization; however, the role of SDF in crystal formation is unknown. We designed an in vitro experiment with calcium phosphate with different SDF concentrations (0.38, 1.52, 2.66, 3.80 mg/mL) to investigate the effect of this additive on the nucleation and growth of apatite crystals. Two control groups were also prepared-calcium phosphate (CaCl 2 ·2H 2 O + K 2 HPO 4 in buffer solution) and SDF (Ag[NH 3 ] 2 F in buffer solution). After incubation at 37 o C for 24 h, the shape and organization of the crystals were examined by bright-field transmission electron microscopy and electron diffraction. Unit cell parameters of the obtained crystals were determined with powder X-ray diffraction. The vibrational and rotational modes of phosphate groups were analyzed with Raman microscopy. The transmission electron microscopy and selected-area electron diffraction confirmed that all solids precipitated within the SDF groups were crystalline and that there was a positive correlation between the increased percentage of crystal size and the concentration of SDF. The powder X-ray diffraction patterns indicated that fluorohydroxyapatite and silver chloride were formed in all the SDF groups. Compared with calcium phosphate control, a contraction of the unit cell in the a-direction but not the c-direction in SDF groups was revealed, which suggested that small localized fluoride anions substituted the hydroxyl anions in hydroxyapatite crystals. This was further evidenced by the Raman spectra, which displayed up-field shift of the phosphate band in all the SDF groups and confirmed that the chemical environment of the phosphate functionalities indeed changed. The results suggested that SDF reacted with calcium and phosphate ions and produced fluorohydroxyapatite. This preferential precipitation of fluorohydroxyapatite with

  18. Correlation between Fluoride in Drinking Water and Its Levels in Breast Milk in Golestan Province, Northern Iran.

    OpenAIRE

    Hossein Faraji; Ali Akbar Mohammadi; Behrouz Akbari-Adergani; Naimeh Vakili Saatloo; Gholamreza Lashkarboloki; Amir Hossein Mahvi

    2014-01-01

    Background: Fluoride is an essential element for human health. However, excess fluoride in drinking water may cause dental and/or skeletal fluorosis. Drinking water is the main route of fluoride intake. The aim of the present study was to measure fluoride levels in human breast milk collected from two regions of Golestan Province, northern Iran with different amount of fluoride concentration of drinking water in Bandar Gaz and Nokande cities and to correlate it with fluoride concentrations in...

  19. High Fluoride and Geothermal Activities In Continental Rift Zones, Ethiopia

    Science.gov (United States)

    Weldesenbet, S. F.; Wohnlich, S.

    2012-12-01

    The Central Main Ethiopian Rift basin is a continental rift system characterized by volcano-tectonic depression endowed with huge geothermal resource and associated natural geochemical changes on groundwater quality. Chemical composition of groundwater in the study area showed a well defined trend along flow from the highland and escarpment to the rift floor aquifer. The low TDS (water at recharge area in the highlands and escarpments evolve progressively into Ca-Na-HCO3 and Na-Ca-HCO3 type waters along the rift ward groundwater flow paths. These waters finally appear as moderate TDS (mean 960mg/l) Na-HCO3 type and as high TDS (> 1000 mg/l) Na-HCO3-Cl type in volcano-lacustrine aquifers of the rift floor. High concentrations of fluoride (up to 97.2 mg/l) and arsenic (up to 98μg/l) are recognized feature of groundwaters which occur mostly in the vicinity of the geothermal fields and the rift lakes in the basin. Fluoride and arsenic content of dry volcaniclastic sediments close to these areas are in the range 666-2586mg/kg and 10-13mg/kg respectively. The relationship between fluoride and calcium concentrations in groundwaters showed negative correlation. Near-equilibrium state attained between the mineral fluorite (CaF2) and the majority of fluoride-rich (>30mg/l) thermal groundwater and shallow cold groundwater. This indicated that the equilibrium condition control the high concentration of fluoride in the groundwaters. Whereas undersaturation state of fluorite in some relatively low-fluoride (waters indicated a dilution by cold waters. Laboratory batch leaching experiments showed that fast dissolution of fluoride from the sediment samples suddenly leached into the interacting water at the first one hour and then remain stable throughout the experiment. The concentrations of leached fluoride from the hot spring deposits, the lacustrine sediments, and the pyroclastic rock are usually low (1% of the total or less than the content in the sediment or rock) but

  20. Fluoride and Geothermal Activities In Continental Rift Zones, Ethiopia

    Science.gov (United States)

    Weldesenbet, S. F.

    2012-12-01

    The Central Main Ethiopian Rift basin is a continental rift system characterized by volcano-tectonic depression endowed with huge geothermal resource and associated natural geochemical changes on groundwater quality. Chemical composition of groundwater in the study area showed a well defined trend along flow from the highland and escarpment to the rift floor aquifer. The low TDS (water at recharge area in the highlands and escarpments evolve progressively into Ca-Na-HCO3 and Na-Ca-HCO3 type waters along the rift ward groundwater flow paths. These waters finally appear as moderate TDS (mean 960mg/l) Na-HCO3 type and as high TDS (> 1000 mg/l) Na-HCO3-Cl type in volcano-lacustrine aquifers of the rift floor. High concentrations of fluoride (up to 97.2 mg/l) and arsenic (up to 98μg/l) are recognized feature of groundwaters which occur mostly in the vicinity of the geothermal fields and the rift lakes in the basin. Fluoride and arsenic content of dry volcaniclastic sediments close to these areas are in the range 666-2586mg/kg and 10-13mg/kg respectively. The relationship between fluoride and calcium concentrations in groundwaters showed negative correlation. Near-equilibrium state attained between the mineral fluorite (CaF2) and the majority of fluoride-rich (>30mg/l) thermal groundwater and shallow cold groundwater. This indicated that the equilibrium condition control the high concentration of fluoride in the groundwaters. Whereas undersaturation state of fluorite in some relatively low-fluoride (waters indicated a dilution by cold waters. Laboratory batch leaching experiments showed that fast dissolution of fluoride from the sediment samples suddenly leached into the interacting water at the first one hour and then remain stable throughout the experiment. The concentrations of leached fluoride from the hot spring deposits, the lacustrine sediments, and the pyroclastic rock are usually low (1% of the total or less than the content in the sediment or rock) but

  1. Selective separation of phosphate and fluoride from semiconductor wastewater.

    Science.gov (United States)

    Warmadewanthi, B; Liu, J C

    2009-01-01

    Hydrofluoric acid (HF) and phosphoric acid (H(3)PO(4)) are widely used in semiconductor industry for etching and rinsing purposes. Consequently, significant amount of wastewater containing phosphate and fluoride is generated. Selective separation of phosphate and fluoride from the semiconductor wastewater, containing 936 mg/L of fluoride, 118 mg/L of phosphate, 640 mg/L of sulfate, and 26.7 mg/L of ammonia, was studied. Chemical precipitation and flotation reactions were utilized in the two-stage treatment processes. The first-stage reaction involved the addition of magnesium chloride (MgCl(2)) to induce selective precipitation of magnesium phosphate. The optimal condition was pH 10 and molar ratio, [Mg(2 + )]/[(PO(4) (3-))], of 3:1, and 66.2% of phosphate was removed and recovered as bobierrite (Mg(3)(PO(4))(2).8H(2)O). No reaction was found between MgCl(2) and fluoride. Calcium chloride (CaCl(2)) was used in the second-stage reaction to induce precipitation of calcium fluoride and calcium phosphate. The optimum molar ratio, [Ca(2 + )]/[F(-)], was 0.7 at pH 10, and residual fluoride concentration of 10.7 mg/L and phosphate concentration of lower than 0.5 mg/L was obtained. Thermodynamic equilibrium was modeled with PHREEQC and compared with experimental results. Sodium dodecylsulfate (SDS) was an effective collector for subsequent solid-liquid removal via dispersed air flotation (DiAF). The study demonstrated that phosphate can be selectively recovered from the wastewater. Potential benefits include recovery of phosphate for reuse, lower required dosage of calcium for fluoride removal, and less amount of CaF(2) sludge.

  2. Profile of Fluoride Release from a Nanohybrid Composite Resin

    Directory of Open Access Journals (Sweden)

    Raquel Assed Bezerra Silva

    2015-02-01

    Full Text Available The aim of this study was to evaluate in vitro the amount and profile of fluoride release from a fluoride-containing nanohybrid composite resin (Tetric® N-Ceram by direct potentiometry. Thirty specimens (5 mm diameter x 3 mm high; n=10/material were made of Tetric® N-Ceram, Vitremer® resin-modified glass ionomer cement (RMGIC (positive control or Filtek® Z350 nanofill composite resin (negative control. The specimens were stored individually in plastic tubes containing 1 mL of artificial saliva at 37°C, which was daily renewed during 15 days. At each renewal of saliva, the amount of fluoride ions released in the solution was measured using a fluoride ion-selective electrode with ion analyzer, and the values obtained in mV were converted to ppm (µg/mL. Data were analyzed statistically by ANOVA and Tukey’s post-hoc test at a significance level of 5%. The results showed that the resins Tetric® N-Ceram and Filtek® Z350 did not release significant amounts of fluoride during the whole period of evaluation (p>0.05. Only Vitremer® released significant amounts of fluoride ions during the 15 days of the experiment, with greater release in first 2 days (p0.05. In conclusion, the nanohybrid composite resin Tetric® N-Ceram did not present in vitro fluoride-releasing capacity throughout the 15 days of study.

  3. Groundwater fluoride and dental fluorosis in southwestern Nigeria.

    Science.gov (United States)

    Gbadebo, A M

    2012-10-01

    This study was carried out to assess the fluoride levels of groundwater from open wells, consumed by the residents of three communities located in two distinct geological terrains of southwestern Nigeria. Fluoride concentration was determined using spectrophotometric technique, while analysis of other parameters like temperature, pH and total dissolve solids followed standard methods. Results of the analysis indicated that groundwater samples from Abeokuta Metropolis (i.e., basement complex terrain) had fluoride content in the range of 0.65 ± 0.21 and 1.20 ± 0.14. These values were found to be lower than the fluoride contents in the groundwater samples from Ewekoro peri-urban and Lagos metropolis where the values ranged between 1.10 ± 0.14-1.45 ± 0.07 and 0.15 ± 0.07-2.20 ± 1.41 mg/l, respectively. The fluoride contents in almost all locations were generally higher than the WHO recommended 0.6 mg/l. Analysis of Duncan multiple range test indicated that there is similarity in the level of significance of fluoride contents between different locations of same geological terrain at p ≤ 0.05. It was also observed that fluoride distribution of groundwater samples from the different geological terrain was more dependent on factors like pH and TDS than on temperature. The result of the analyzed social demographic characteristics of the residents indicated that the adults (between the age of 20 and >40 years) showed dental decay than the adolescent (water of the populace. Further investigation on all sources of drinking water and other causes of tooth decay in the area is suggested.

  4. Fluoride potentiates tubulointerstitial nephropathy caused by unilateral ureteral obstruction.

    Science.gov (United States)

    Kido, Takamasa; Tsunoda, Masashi; Sugaya, Chiemi; Hano, Hiroshi; Yanagisawa, Hiroyuki

    2017-12-01

    The contamination of ground water by fluoride has been reported worldwide. Most fluoride (approximately 70%) is filtered by the kidneys; humans or experimental animals with renal damage therefore may be more affected by fluoride exposure than those with normal kidney function. Tubulointerstitial fibrosis, which involves macrophage-promoted extracellular matrix production and myofibroblast migration, can be induced in rats by unilateral ureteral obstruction (UUO). We examined the effects of fluoride exposure on tubulointerstitial fibrosis in the obstructed kidney of UUO rats. The left ureters of 6-week-old male rats were ligated using silk sutures. Fluoride was then administered for 2 weeks at doses of 0, 75, and 150ppm in the drinking water. Real-time polymerase chain reaction was performed to analyze transforming growth factor beta 1 (TGF-β1) transcription; histological and immunohistochemical staining were used to identify positive areas within the renal cortex and staining-positive cells by image analysis. Significant increases were observed in the obstructed kidneys of UUO rats exposed to 150ppm fluoride (compared to 0ppm) for areas or number of cells that stained with Masson trichrome or with antibodies against collagen type I, alpha-smooth muscle actin (α-SMA, a myofibroblast marker), ED1, ED2, and ED3 (macrophage markers), and TGF-β1. Taken together, these observations suggested that fluoride exacerbates tuburointerstitial nephropathy resulting from UUO, and that this effect occurs via activation of the M2 macrophage-TGF-β1-fibroblast/myofibroblast-collagen synthesis pathway. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. [Excessive fluoride inducing calcium overload and apoptosis of ameloblasts].

    Science.gov (United States)

    Ying, Zhang; Lin, Ma; Jian, Li; Ming, Zhong; Kaiqiang, Zhang; Hefeng, Gu

    2014-12-01

    To study the effect of excessive fluoride on calcium overload and apoptosis in cultured rat ameloblasts in vitro. Logarithmic-phase ameloblasts (HAT-7) were treated with 0, 0.4, 0.8, 1.6, 3.2, and 6.4 mmol · L(-1) sodium fluoride (NaF) solution. Cell activities were detected by using a Cell Counting Kit 8 (CCK-8) assay after 48 h of treatment. The effect of fluoride on cell apoptosis was analyzed by using flow cytometry. Excessive fluoride-induced calcium concentration and calreticulin expression changes in ameloblasts were detected by using laser scanning confocal microscopy, Western blot analysis, and real-time quantitative polymerase chain reaction. NaF inhibited ameloblast activity at 1.6, 3.2, and 6.4 mmol · L(-1) (dose-dependent) after 48 h of induction. The Ca2+ fluorescence intensity of HAT-7 cells incubated with 1.6 and 3.2 mmol · L(-1) NaF was higher than that in the control group. The fluoride-induced early-stage apoptosis of ameloblasts after 48 h of induction and the early-stage apoptosis rate was positively correlated with fluoride concentration. Calreticulin mRNA expression in HAT-7 cells was higher than that in the control group after 48 h of incubation with 0.8, 1.2, and 1.6 mmol · L(-1) NaF. Excessive fluoride-induced calcium overload in ameloblasts and further caused endoplasmic reticulum stress-mediated apoptosis.

  6. Removal of excess fluoride from water by aluminum hydroxide

    Directory of Open Access Journals (Sweden)

    Beneberu Shimelis

    2006-06-01

    Full Text Available The efficiency of untreated hydrated alumina (UHA and thermally treated hydrated alumina (THA obtained from hydrolysis of locally manufactured aluminum sulfate to remove fluoride from aqueous solution has been investigated in batch and continuous operation. The parameters considered were contact time and adsorbent dose, thermal pre-treatment of adsorbent, initial fluoride concentration and pH. The adsorption was rapid during the initial 20 min, but significant amount (> 90 % was removed within one hour at an optimum adsorbent dose of 1.6 g/L for initial F- concentration of 20 mg/L. The removal efficiency of F was increased with adsorbent dosage. Fluoride adsorption efficiencies increase with increase in the thermal treatment temperature up to 200 °C, but further increase in temperature resulted in decreased removal efficiency. For application in continuous packed bed column, treatment at 300 °C was taken as an optimum value. Fluoride adsorption capacity increases linearly with increase in F- concentration. High defluoridation efficiency was achieved using both UHA and THA within a pH range of 4.0 to 9.0. The adsorption data at ambient pH were well fitted to the Freundlich isotherm model with a minimum capacity of 23.7 mg F-/g and 7.0 mg F-/g for THA and UHA, respectively. The kinetic studies showed that the adsorption reaction of fluoride removal by hydrated alumina can be well described by a pseudo-second-order rate equation. Continuous packed bed column experiment using THA indicated that 4.5 g of THA could treat 6 L of water containing 20 mg/L fluoride before breakthrough. Hence, both UHA and THA can be applied for the treatment of water with high fluoride content.

  7. In vivo and in vitro studies of a cetylamine fluoride mouthrinse: evaluation of a device used for in vitro experiments

    Directory of Open Access Journals (Sweden)

    CARVALHO Sílvia Magaly Sasso

    1999-01-01

    Full Text Available A mouthrinse containing cetylamine fluoride (230 ppm in fluoride was prepared for in vitro studies of fluoride clearance and adsorption by enamel and/or hydroxyapatite using a device that simulates the oral cavity. In vivo studies of fluoride clearance from this mouthrinse were conducted and compared with other fluoride sources. The amount of fluoride adsorbed to tooth blocks or powdered hydroxyapatite, both treated with this cetylamine fluoride mouthrinse once or twice a day, was determined. The results of these studies showed that it is possible to prepare a mouthrinse with cetylamine fluoride for alternative use by patients for the prevention and therapy of dental caries.

  8. Characterization of cerium fluoride nanocomposite scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Stange, Sy [Los Alamos National Laboratory; Esch, Ernst I [Los Alamos National Laboratory; Brown, Leif O [Los Alamos National Laboratory; Couture, Aaron J [Los Alamos National Laboratory; Mckigney, Edward A [Los Alamos National Laboratory; Muenchausen, Ross E [Los Alamos National Laboratory; Del Sesto, Rico E [Los Alamos National Laboratory; Gilbertson, Robert D [Los Alamos National Laboratory; Mccleskey, T Mark [Los Alamos National Laboratory; Reifarth, Rene [Los Alamos National Laboratory

    2009-01-01

    Measurement of the neutron capture cross-sections of a number of short-lived isotopes would advance both pure and applied scientific research. These cross-sections are needed for calculation of criticality and waste production estimates for the Advanced Fuel Cycle Initiative, for analysis of data from nuclear weapons tests, and to improve understanding of nucleosynthesis. However, measurement of these cross-sections would require a detector with a faster signal decay time than those used in existing neutron capture experiments. Crystals of faster detector materials are not available in sufficient sizes and quantities to supply these large-scale experiments. Instead, we propose to use nanocomposite detectors, consisting of nanoscale particles of a scintillating material dispersed in a matrix material. We have successfully fabricated cerium fluoride (CeF{sub 3}) nanoparticles and dispersed them in a liquid matrix. We have characterized this scintillator and have measured its response to neutron capture. Results of the optical, structural, and radiation characterization will be presented.

  9. Advanced Carbon Fluorides For Primary Lithium Batteries

    Directory of Open Access Journals (Sweden)

    Guérin K.

    2017-01-01

    Full Text Available Li-CFx battery using a specific fluorinated nanocarbon as cathode material exhibits a capacity exceeding the expected theoretical value when used as an electrode material in primary lithium battery. Carbon nanodiscs were partially fluorinated by atomic fluorine released by thermal decomposition of TbF4, and the capacity of this material was up to 1180 mAh.g−1, whereas a theoretical value of 847 mAh.g−1 for the CF0.95 sample was calculated. The obtained value is also higher than the maximum one of 865 mAh.g−1 expected for CF1 carbon fluorides. The discharge mechanism was investigated using mainly SEM and solid state NMR in order to understand this “extracapacity”. Both the unfluorinated carbon and the LiF covering, which is formed outside the carbon lattice during the discharge mechanism, play a key role for the achievement of the extracapacity by the consumption of Li+ to form Li2F+ species stabilized by the carbon host structure formed after the electrochemical defluorination.

  10. Synthesis, Characterization and Antibacterial Studies of N-(Benzothiazol-2-yl-4-chlorobenzenesulphonamide and Its Neodymium(III and Thallium(III Complexes

    Directory of Open Access Journals (Sweden)

    Lawrence Nnamdi Obasi

    2017-02-01

    Full Text Available N-(Benzothiazol-2-yl-4-chlorobenzenesulphonamide (NBTCS was synthesized by condensation reaction of 4-chlorobenzenesulphonyl chloride and 2-aminobenzothiazole in acetone under reflux. Neodymium(III and thallium(III complexes of the ligand were also synthesized. Both ligand and metal complexes were characterized using UV-Vis, IR, 1H- and 13C-NMR spectroscopies, elemental analysis and molar conductance measurement. IR studies revealed that the ligand is tridentate and coordinates to the metal ions through nitrogen and oxygen atoms of the sulphonamide group and nitrogen atom attached to benzothiazole ring. The neodymium(III complex displays a coordination number of eight while thallium(III complex displays a coordination number of six. The ligand and its complexes were screened in vitro for their antibacterial activities against Escherichia coli strains (E. coli 6 and E. coli 13, Proteus species, Staphylococcus aureus and Pseudomonas aeruginosa using the agar well diffusion technique. The synthesized compounds were found to be more active against the microorganisms screened relative to ciprofloxacin, gentamicin and co-trimoxazole.

  11. Comparative study of body surface isopotential map, left ventriculogram and thallium-201 myocardial scintigram in patients with old lateral myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Naoyuki

    1988-01-01

    In 16 patients with old lateral myocardial infarction, body surface isopotential maps and 12 lead electrocardiograms were compared with left ventriculographic findings. In addition 8 of these subjects were performed thallium-201 myocardial scintigraphy in order to determine the location and extent of myocardial necrosis. Common 12 lead electrocardiographic findings of the subjects were initial Q waves more than 30 msec and inverted T waves in only aVL lead. The patients were classified into 4 groups according to the location and extent of ventricular wall motion abnormalities group I (6 cases) showed hypokinesis in the anterior segment, group II (5 cases): akinesis in the anterior segment and hypokinesis in the seg. 6, group III (4 cases): hypokinesis in the anterior segment and seg. 7, group IV (1 case): hypokinesis in the anterior segment and seg. 4, 7. And each of the 4 groups demonstrated characteristic findings of surface isopotential maps. Group II with coexisting hypokinesis in the seg. 6 showed surface isopotential maps additional pattern of anterior myocardial infarction, and group III with coexisting hypokinesis in the seg. 7 showed additional patterns of posterior myocardial infarction. The classification according to the abnormality of ventricular wall motion was also conformed with the thallium-201 myocardial scintigraphic findings except one case. These results suggest that body surface isopotential map is more useful than the 12 lead electrocardiogram in detecting the location and extent of left ventricular wall motion abnormality in patients with old lateral myocardial infarction. (author) 53 refs.

  12. Serial thallium-201 imaging at rest in patients with unstable and stable angina pectoris: relationship of myocardial perfusion at rest to presenting clinical syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Brown, K.A.; Okada, R.D.; Boucher, C.A.; Phillips, H.R.; Strauss, H.W.; Pohost, G.M.

    1983-07-01

    In order to determine whether there are differences in myocardial perfusion at rest among patients with various unstable and stable angina syndromes, serial thallium-201 imaging was performed at rest in 19 patients presenting with rapidly worsening exertional angina (unstable angina, group A), 12 patients with rest angina alone without exertional symptoms (unstable angina, group B), and 34 patients with chronic stable angina. No patient had an episode of angina within 4 hours of study. Nineteen of 19 (100%) patients in group A demonstrated transient defects compared to only 3 of 12 (25%) patients in group B (p less than 0.0001) and 4 of 34 (12%) stable angina patients (p less than 0.0001). The majority of zones demonstrating transient defects in group A were associated with hypokinesis of the corresponding left ventriculogram segment without associated ECG evidence of previous infarction. There were no significant differences in the frequency of persistent thallium defects, severity of angiographic coronary artery disease, or frequency of regional wall motion abnormalities of myocardial segments supplied by stenotic coronary arteries among the three groups of patients. Transient defects have been shown to reflect reduction in regional coronary blood flow to viable myocardium. Therefore, we conclude that regional resting hypoperfusion of viable myocardium is far more common in patients with exertional unstable angina symptoms than in patients with rest angina alone or chronic stable angina.

  13. Stabilization of fluoroindate glasses by magnesium fluoride and other heavy metal fluorides

    Directory of Open Access Journals (Sweden)

    B. J. Costa

    1998-06-01

    Full Text Available Their extended transparency in the IR makes them attractive for use as optical fibers for CO laser power delivery and optical amplification. This paper firstly describes the spectacular stabilizing effect of MgF2 on the binary system InF3-BaF2. The investigation of the InF3-BaF2-MgF2 system led to samples up to 5mm in thickness. Further optimization of this system was achieved by incorporation of limited amounts of other fluorides and resulted in increased resistence to devitrification. The second approach of this work was concerned to the investigation of the pseudo-ternary system InF3-GdF3-GaF3 at constant concentrations of ZnF2-SrF2-BaF2-NaF. Several compositions were studied in this system. The samples presented a better thermal stability when compared to other families of fluoride glasses. Therefore, these glasses seem to be very promising for the fabrication of special optical fibers. Thermal data are reported.

  14. An Overview of Liquid Fluoride Salt Heat Transport Systems

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, David Eugene [ORNL; Cetiner, Sacit M [ORNL

    2010-09-01

    Heat transport is central to all thermal-based forms of electricity generation. The ever increasing demand for higher thermal efficiency necessitates power generation cycles transitioning to progressively higher temperatures. Similarly, the desire to provide direct thermal coupling between heat sources and higher temperature chemical processes provides the underlying incentive to move toward higher temperature heat transfer loops. As the system temperature rises, the available materials and technology choices become progressively more limited. Superficially, fluoride salts at {approx}700 C resemble water at room temperature being optically transparent and having similar heat capacity, roughly three times the viscosity, and about twice the density. Fluoride salts are a leading candidate heat-transport material at high temperatures. Fluoride salts have been extensively used in specialized industrial processes for decades, yet they have not entered widespread deployment for general heat transport purposes. This report does not provide an exhaustive screening of potential heat transfer media and other high temperature liquids such as alkali metal carbonate eutectics or chloride salts may have economic or technological advantages. A particular advantage of fluoride salts is that the technology for their use is relatively mature as they were extensively studied during the 1940s-1970s as part of the U.S. Atomic Energy Commission's program to develop molten salt reactors (MSRs). However, the instrumentation, components, and practices for use of fluoride salts are not yet developed sufficiently for commercial implementation. This report provides an overview of the current understanding of the technologies involved in liquid salt heat transport (LSHT) along with providing references to the more detailed primary information resources. Much of the information presented here derives from the earlier MSR program. However, technology has evolved over the intervening years

  15. Caries status in 16 year-olds with varying exposure to water fluoridation in Ireland.

    LENUS (Irish Health Repository)

    Mullen, J

    2012-12-01

    Most of the Republic of Ireland\\'s public water supplies have been fluoridated since the mid-1960s while Northern Ireland has never been fluoridated, apart from some small short-lived schemes in east Ulster.

  16. Behaviour of fluoride and dissolved silicon in Gouthami Godavari estuarine environment

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.; Sudhakar, U.; Varaprasad, S.J.D.

    The concentrations of fluoride and dissolved silicon in Gouthami-Godavari estuarine region (Andhra Pradesh, India) have been measured as a function of chlorinity during different seasons. Fluoride and dissolved silicon behave conservatively during...

  17. Estimation of fluoride levels in various commercially available carbonated soft drinks in Chandigarh city, India

    Directory of Open Access Journals (Sweden)

    Mohit Bansal

    2015-01-01

    Full Text Available Introduction: Fluoride has a preventive action on dental caries. However, Excessive ingestion of fluoride from different sources can lead to the development of dental fluorosis. Aim: To estimate fluoride levels in various commercially available carbonated soft drinks available in Chandigarh city. Materials and Methods: Twelve different brands of commercially available soft drinks were purchased from three different places and divided into three groups. Fluoride levels were estimated using fluoride test strips Quantofix 37211 Fluka; Sigma-Aldrich. Results: Fluoride levels ranged from 0.12 to 0.42 mg/dl F with the maximum level in Thumbs up and least in Diet Pepsi. Conclusion: The levels of fluoride varied in various carbonated soft drinks analyzed. This could contribute significantly to the total fluoride intake from all sources and thus be an important risk factor for the development of dental fluorosis.

  18. A NOVEL BIO-WASTE INCORPORATED ALGINATE SORBENT FOR DE-FLUORIDATION OF WATER

    Directory of Open Access Journals (Sweden)

    Carmalin Sophia Ayyappan

    2015-09-01

    Full Text Available This study evaluates the feasibility of using tamarind (Tamarindus indica seed powder for de-fluoridation of fluoride contaminated water. Batch study confirmed that tamarind seeds in dry powder form could remove 87% of fluoride from water. This bio-sorbent can be used effectively in areas where fluoride concentrations are above the permissible limits of 1.5 mg·l-1 as per WHO Standard, 1984. Tamarind seed powder was incorporated in a matrix of sodium alginate and made into gel-beads. The beads were tested for de-fluoridation efficiency by conducting column studies. The effect of various factors, such as flow rate, retention time, and the number of runs on the efficacy of fluoride removal was also studied. The results revealed that flow rate did not seem to have much effect on the percentage fluoride removal but the fluoride concentration decreased drastically upon greater retention time and multiple runs.

  19. Fluoride content of still bottled waters available in the North-East of England, UK

    National Research Council Canada - National Science Library

    Zohouri, F V; Moynihan, P J; Maguire, A

    2003-01-01

    .... All samples were still spring, mineral or distilled waters, sold in plastic bottles. The fluoride content of all samples was determined, in duplicate, using a Fluoride Ion Selective Electrode. The mean (+/- SD...

  20. Socio-economic differences in public opinion regarding water fluoridation in Queensland.

    Science.gov (United States)

    Mummery, W Kerry; Duncan, Mitchell; Kift, Ryan

    2007-08-01

    To describe public opinion relating to the fluoridation of drinking water in a sample of the Queensland population. Data were collected by means of a computer-assisted telephone interview survey from a sample of the Queensland population. Descriptive statistics and logistical regression were used to examine associations between variables. Seventy per cent of the total sample supported water fluoridation of their local supply. More than 71% of the total sample agreed that water fluoridation was safe. People living in areas of higher socio-economic/relative socio-economic advantage were more likely to support the addition of fluoride to local drinking water and agree that it was safe. Opinions about fluoridation varied by respondent age and gender. General support was found in this sample of the Queensland population for fluoridation of drinking water. In Queensland, fluoridation of the water supply is now a political decision. Information about public opinion on fluoridation may assist decision makers in the final determination.