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fluoride water

T S Premaraj, N Rohani, D Covey, S Premaraj
OBJECTIVES: To evaluate the surface properties of two commercially available sealants (Pro Seal(®) (PS) and Opal(®) Seal(TM) (OS)) in terms of fluoride(F) release, biofilm formation of Streptococcus mutans and Lactobacillus and the ability to resist acid penetration. SETTING: University of Nebraska Medical Center. MATERIAL & METHODS: Discs of similar diameter and thickness were made from OS and PS. Discs were soaked in double-distilled water, and F released was measured with fluoride meter daily for 14 consecutive days, then at 21 and 28 days...
June 2017: Orthodontics & Craniofacial Research
Frederico Barbosa de Sousa, Isabel Maria Porto Lelis, Regina Célia Bressan Queiroz Figueiredo, Andressa Cavalcanti Pires, Raquel Fernanda Gerlach
AIM: Capillarity theory predicts that the pore volume infiltrated by a liquid in a body with tubular capillaries is directly proportional to the capillary radius. The expected volume available for infiltration is the loosely bound water volume, which can be related to the capillary radii. We tested the hypothesis that the proportion of the pore volume infiltrated by resin infiltrant (Vratio(resin)) is correlated and agrees with the proportion of the pore volume with loosely bound water ( [Formula: see text] )...
June 15, 2017: Archives of Oral Biology
Manh-Thuong Nguyen, Phong Nam Pham
There are several factors that affect the dynamics of adsorbed hydrogen atoms on a carbon surface, here, using density-functional calculations we show that coadsorption can be a highly influential factor. The diffusion of hydrogen adsorbed on graphene is explored in the presence of H-containing molecules. Without coadsorbates the diffusion barrier of H on graphene is 0.94 eV while with water/ammonia it is 0.85/0.12 eV. The low barrier in the case of ammonia is attributed to the formation of a stable intermediate state NH$_4$ while such a stable state is not found in the case of water...
June 20, 2017: Journal of Physical Chemistry. A
Yanqun Wang, Yizhen Tang, Youxiang Shao
Catalytic dehydration and dehydrogenation reactions of ethanol have been investigated systematically using the ab initio quantum chemistry methods The catalysts include water, hydrogen peroxide, formic acid, phosphoric acid, hydrogen fluoride, ammonia, and ethanol itself. Moreover, a few clusters of water and ethanol were considered to simulate the catalytic mechanisms in supercritical water and supercritical ethanol. The barriers for both dehydration and dehydrogenation can be reduced significantly in the presence of the catalysts...
May 17, 2017: Journal of Molecular Graphics & Modelling
Jicun Li, Feng Wang
Simple pair-wise potentials for five alkali ions and four halide ions were developed by only fitting to ab initio MP2 forces with the adaptive force matching (AFM) method. Without fitting to any experimental information, the AFM models predict the hydration free energies of all 10 fluoride and chloride salts formed by these ions within 1.5% of experimental reference. The predicted hydration free energies for the 10 bromide and iodide salts are within 5-6% of experimental references with the larger error likely due to the neglect of explicit treatment of polarization and charge transfer...
June 16, 2017: Journal of Physical Chemistry. B
Kadriye Görkem Ulu Güzel, Zuhal Kirzioğlu, Ali Kudret Adiloğlu, Münciye Semra Özay Ertürk
Objective: The aim of our study was to evaluate the effect of fluoride on salivary immunoglobulin and sialic acid levels in children with dental fluorosis and healthy teeth who live in places with high fluoride concentration in drinking water. Method: Fifty-one (51) healthy children between 6 and 12 years old with no caries were randomly selected from primary schools enrolled in the dental-care program operated by the Department of Pediatric Dentistry. The children were divided into two groups: group I comprised 26 children with dental fluorosis [Thylstrup-Fejerskov Dental Fluorosis Index (TFI) = 4] who lived in Isparta (2...
April 2017: Revista da Associação Médica Brasileira
Han-Na Kim, Jeong-Hee Kim, Se-Yeon Kim, Jin-Bom Kim
This study aimed to confirm the association between the community water fluoridation (CWF) programme and dental caries prevention on permanent teeth, comparing to a control area, neighbouring population without the programme, and verifying whether the programme can reduce the socio-economic inequality related to the oral health of children in Korea. Evaluation surveys were conducted among 6-, 8-, and 11-year-old children living in Okcheon (CWF) and neighbouring Yeongdong (non-CWF, control area) towns in South Korea...
June 13, 2017: International Journal of Environmental Research and Public Health
Mei Wang, Hong-Bin Luo, Jin Zhang, Shao-Xian Liu, Chen Xue, Yang Zou, Xiao-Ming Ren
Proton conducting materials have important technological applications as key components in electrochemical devices, including fuel cells, electrochemical sensors, electrochemical reactors and electrochromic displays. And the exploration of novel proton conducting materials is significant for the development of efficient electrochemical devices. In this study, we have investigated the proton conductance of an open-framework manganese(ii) phosphite, (NH4)0.59(H3O)1.41Mn5(HPO3)6 (1). The open-framework manganese(ii) phosphate shows superior water-stability and excellent thermal stability...
June 9, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Zhenya Zhu, Lei Wang, Yawei Xu, Qingqing Li, Jialiang Jiang, Xudong Wang
Graphene oxide (GO) and lithium chloride (LiCl) were introduced into poly (vinylidene fluoride) (PVDF) membranes prepared using the immersion precipitation technique. The hydrophilicity, water flux, X-ray diffraction (XRD), zeta potential, SEM and AFM images of membranes were investigated. By adjusting the content of GO from 0wt% to 0.9 wt%, the water flux of PVDF/GO/LiCl nanohybrid membranes varied from 48.4L/m(2)h to 61.90L/m(2)h at 100kPa. Because of the synergistic effects of GO and LiCl particles, the surface free energy (|ΔGs|) of M3 (0...
May 23, 2017: Journal of Colloid and Interface Science
Ehsanullah Hayat, Alper Baba
Water is the main source of energy production and economy in Afghanistan where agriculture accounts for more than 50% of the country's gross domestic product (GDP). Access to safe drinking water is still a problem in the country, which has caused different health issues and even child mortality especially in rural areas. Groundwater is the main source of drinking water in the country. However, little knowledge is available about the quality of groundwater throughout the entire country, and its quality has not been investigated extensively yet like in other countries in the world...
July 2017: Environmental Monitoring and Assessment
Mani Arulkumar, Raji Vijayan, Sakayanathan Penislusshiyan, Palanivel Sathishkumar, Jayaraman Angayarkanni, Thayumanavan Palvannan
BACKGROUND: Toxicity due to excess fluoride concentration in drinking water is of great concern in people who rely only on the ground water as their water source in many region of the world. METHODS: We collected samples and examined the toxicity of fluoride in a population residing at Salem, Dharmapuri and Krishnagiri districts of Tamil Nadu, India and measured HDL bound enzyme (PON1), erythrocyte membrane bound enzymes (acetylcholinesterase, AChE) and adenosine 5' triphosphatase (ATPases), plasma enzyme (butyrylcholinesterase, BChE) and rate limiting enzyme in heme biosynthesis (delta aminolevulinic acid dehydratase, δ-ALAD) activities...
June 1, 2017: Clinica Chimica Acta; International Journal of Clinical Chemistry
Liguo Shen, Shushu Feng, Jianxi Li, Jianrong Chen, Fengquan Li, Hongjun Lin, Genying Yu
This study provided the first attempt of grafting hydrophobic polyvinylidene fluoride (PVDF) membrane with hydrophilic hydroxyethyl acrylate (HEA) monomer via a radiation grafting method. This grafted membrane showed an enhanced hydrophilicity (10° decrease of water contact angle), water content ratio, settling ability and wettability compared to the control membrane. Interestingly, filtration tests showed an improved dependence of water flux of the grafted membrane on the solution pH in the acidic stage. Atomic force microscopy (AFM) analysis provided in-situ evidence that the reduced surface pore size of the grafted membrane with the solution pH governed such a dependence...
June 2, 2017: Scientific Reports
Vineet Kumar Rathore, Prasenjit Mondal
The presence of arsenic and fluoride in groundwater has been observed throughout the world. Many technologies have been developed by various research groups in order to tackle this problem. Adsorption has emerged as one of the best possible technique for the removal of arsenic, fluoride and many other pollutants from drinking water. Although a considerable amount of work has been published on the adsorptive removal of arsenic and fluoride, the area related to the management of spent adsorbent is not well explored...
May 31, 2017: Journal of Environmental Management
Yunjin Yao, Chao Lian, Yi Hu, Jie Zhang, Mengxue Gao, Yu Zhang, Shaobin Wang
Iron nanoparticles (NPs) embedded in S, N-codoped carbon were prepared by one-step pyrolysis of a homogeneous mixture consisting of Fe, S, N, C precursors, and then immobilized in poly (vinylidene fluoride) membranes as a multifunctional catalytic system (NSC-Fe@PVDF) to effectively activate peroxymonosulfate (PMS) and oxidize organic compounds in water. The NSC-Fe@PVDF membranes effectively decolorized organic pollutants at a wide pH range (2.05-10.85), due to the synergistic effects between the S, N-doped carbon and iron NPs...
May 15, 2017: Journal of Hazardous Materials
N Pérez-Pérez, M E Irigoyen-Camacho, A S Boges-Yañez
OBJECTIVE: To assess the association between dental fluorosis and maternal education in schoolchildren of medium and low socioeconomic status in a low income region of Mexico. DESIGN: Cross-sectional study. SETTINGS: Public schools in the south-central region of Oaxaca, Mexico where the mean fluoride water concentration was 1.01 mg/L (SD 0.21; range 0.71-1.40). Fluoridated salt (200mgF/kg) was available in the region. PARTICIPANTS: 794 schoolchildren...
June 2017: Community Dental Health
Zhongguo Zhang, Dan Liu, Yu Qian, Yue Wu, Peiran He, Shuang Liang, Xiaozheng Fu, Jiding Li, Changqing Ye
A submerged internal circulating membrane coagulation reactor (MCR) was used to treat surface water to produce drinking water. Polyaluminum chloride (PACl) was used as coagulant, and a hydrophilic polyvinylidene fluoride (PVDF) submerged hollow fiber microfiltration membrane was employed. The influences of trans-membrane pressure (TMP), zeta potential (ZP) of the suspended particles in raw water, and KMnO4 dosing on water flux and the removal of turbidity and organic matter were systematically investigated...
June 2017: Journal of Environmental Sciences (China)
Raúl Alberto Durán, Estela Liliana Durán, Graciela de Jesús Ojeda, Walter Alfredo Castellanos
This work studied the geographical distribution of fluoride content in the public water supply in the province of Tucumán, Argentina. A total of 1,210 samples were collected in 190 localities of the 17 departments of the province during the 2008-2012 period. The analytical determination was performed using the SPADNS method and QGis 2.16 was used for processing the information. The fluoride content requirements in the studied localities were determined according to the Argentine Food Code. The results showed that 94% of population studied consumed water with fluoride concentrations below the recommended limits, 5% were exposed to fluoride concentrations above the required maximum limit and 1% consumed water at optimal fluoride concentrations...
January 2017: Salud Colectiva
M Norman, S Twetman, A Hultgren Talvilahti, E Granström, C Stecksén-Blicks
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 of age. Intervention: In a randomized order, participants drank 1.5 dl milk once daily for 7 days with no fluoride added (control), 0...
March 2017: Community Dental Health
D J Worsley, P G Robinson, Z Marshman
Objective: To summarise the literature on urgent dental care and to identify research priorities on the organisation and delivery of urgent dental services. Basic research design: Scoping review using Andersen's behavioural model of health service utilisation for a framework analysis of the data. Main outcome measures: Gaps in the literature, defined as those factors and interactions identified by Andersen's model as having a contributory role in access to health services that were not evident in the source papers...
March 2017: Community Dental Health
Yuan-Wei Huang, Zuo-Ming Wang, Xi Yan, Jun Chen, Ya-Jun Guo, Wan-Zhong Lang
Novel ultrafiltration membranes with both superior antibacterial and self-cleaning properties were fabricated. By using a non-solvent induced phase separation method (NIPS), N-halamine epoxide and siloxane were grafted onto the multi-walled carbon nanotubes (N-Si-MWNTs) to fabricate polyvinylidene fluoride (PVDF) hybrid membranes. The membrane morphology was observed under a field emission scanning electron microscopy. The results demonstrated that the PVDF hybrid membranes had an asymmetrical structure, and their hydraulic permeability was evidently enhanced with the addition of modified MWNTs...
May 24, 2017: Journal of Colloid and Interface Science
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