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fluoride water

Igor Ariz-Extreme, Jochen S Hub
Approximately 90% of the structures in the Protein Data Bank (PDB) were obtained by X-ray crystallography or electron microscopy. Whereas the overall quality of structure is considered high, thanks to a wide range of tools for structure validation, uncertainties may arise from density maps of small molecules, such as organic ligands, ions or water, which are non-covalently bound to the biomolecules. Even with some experience and chemical intuition, the assignment of such disconnected electron densities is often far from obvious...
2018: PloS One
Neha Arun Joshi, C G Ajithkrishnan
Objective: To investigate scalp hair as biomarker for chronic fluoride exposure among fluoride endemic and low fluoride areas. Methodology: Two areas were identified in Vadodara district, Ajod, as a low fluoride area (Fluoride content of drinking water = 0.11 ppm) and Karsan, a high fluoride area (fluoride content in drinking water = 3.43 ppm). The study was performed on a total of 36 participants from the two villages, 18 from Ajod and 18 from Karsan. Thylstrup Fejerskov Index (TFI) was recorded for each of the participants and sample of hair was collected from the occipital region...
March 2018: International Journal of Trichology
Thanusha Perera, Shirani Ranasinghe, Neil Alles, Roshitha Waduge
BACKGROUND: High fluoride levels in drinking water in relation to the prevalence of chronic kidney disease of unknown etiology (CKDu) in Sri Lanka were investigated using rats as an experimental model. METHOD: The effects of fluoride after oral administration of Sodium fluoride (NaF) at levels of 0, 0.5, 5 and 20 ppm F- were evaluated in adult male Wistar rats. Thirty-six rats were randomly divided into 4 groups (n = 9), namely, control, test I, II, and III...
May 16, 2018: Environmental Health and Preventive Medicine
Robert Naumann, Florian Lehmann, Martin Goez
We have explored alkyl substitution of the ligands as a means to improve the performance of the title complexes in photoredox catalytic systems that produce synthetically useable amounts of hydrated electrons through photon pooling. Despite generating a superreductant, these electron sources only consume the bioavailable ascorbate and are driven by a green light-emitting diode (LED). The substitutions influence the catalyst activity through the quenching and recombination rates across the micelle-water interface, and the photoionization quantum yield...
May 16, 2018: Chemistry: a European Journal
Ahmet Altun, Frank Neese, Giovanni Bistoni
The local energy decomposition (LED) analysis allows for a decomposition of the accurate domain-based local pair natural orbital CCSD(T) [DLPNO-CCSD(T)] energy into physically meaningful contributions including geometric and electronic preparation, electrostatic interaction, interfragment exchange, dynamic charge polarization, and London dispersion terms. Herein, this technique is employed in the study of hydrogen-bonding interactions in a series of conformers of water and hydrogen fluoride dimers. Initially, DLPNO-CCSD(T) dissociation energies for the most stable conformers are computed and compared with available experimental data...
2018: Beilstein Journal of Organic Chemistry
Jaishabanu Ameeramja, Vishnu Vignesh Kanagaraj, Ekambaram Perumal
We have found that protocatechuic acid methyl ester (PCAME) attenuates fluoride (F- ) toxicity in lung epithelial cells (A549). However, these finding has to be confirmed with in vivo studies. Further, the effect of PCAME on F- induced pulmonary fibrosis and inflammation remains limited. Hence, the present study is aimed to determine the protective effect PCAME against F- induced pulmonary toxicity in female albino Wistar rats. The animals were treated with sodium fluoride (NaF, 300 ppm in drinking water ad libitum) alone or in combination with PCAME (25 or 50 mg/kg bw/day by oral intubation) for 60 days and analyzed for changes in lung histology, oxidative stress, inflammation, apoptosis and fibrosis markers...
May 11, 2018: Food and Chemical Toxicology
Yiming Zhang, Wei Zhang, Luis F Cházaro-Ruiz
In this work, polyvinylidene fluoride (PVDF)/polyaniline (PANI) heterogeneous anion-exchange membranes filled with pore-forming agents polyvinylpyrrolidone (PVP) and lithium chloride were prepared by the solution-casting technique using the solvent 1-methyl-2-pyrrolidone (NMP) and a two-step phase inversion procedure. Key properties of the as-prepared membranes, such as hydrophilicity, water content, ion exchange capacity, fixed ion concentration, conductivity and transport number were examined and compared between membranes in different conditions...
May 2018: Water Science and Technology: a Journal of the International Association on Water Pollution Research
H Kalsbeek
Shortly after the Second World War it became known in the Netherlands that fluoride can contribute to the prevention of dental caries. As to how this effect was achieved, opinions differed. Initially, the dominant the view was that fluoride had to be absorbed into the enamel and dentine during tooth formation to make the teeth resistant to caries. Later it was discovered that decalcification of the enamel is inhibited if fluoride is present in the dental plaque. While in the beginning water fluoridation was considered to be the most effective measure to prevent caries, the current position is that tooth brushing with fluoride toothpaste plays the most important role in caries prevention...
May 2018: Nederlands Tijdschrift Voor Tandheelkunde
Narada Bombuwala Dewage, Achala S Liyanage, Charles U Pittman, Dinesh Mohan, Todd Mlsna
α-Fe2 O3 and Fe3 O4 dispersed on high surface area (663 m2 /g) Douglas fir biochar (BC) was prepared for fast nitrate and fluoride ion removal from water using magnetic separations. This biochar, made originally at 900 °C, was impregnated with FeCl3 and converted by pyrolysis at 600 °C to magnetic (494 m2 /g) biochar (MBC). MBC and its precursor BC were characterized using SEM, SEM-EDX, STEM, SBET , PZC measurements, XRD analysis, and XPS. Dispersed α-Fe2 O3 and Fe3 O4 particles caused magnetization and generated most adsorption sites, causing more nitrate and fluoride uptake than BC...
May 2, 2018: Bioresource Technology
Yang Li, Junsheng Chen, Tian-Shu Chu
The sensing mechanism of a fluoride-anion probe BODIPY-amidothiourea (1c) has been elucidated through the density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations. The theoretical study indicates that in the DMSO/water mixtures the fluorescent sensing has been regulated by the fluoride complex that formed between the probe 1c/two water molecules and the fluoride anion, and the excited-state intermolecular hydrogen bond (H-B) plays an important role in the fluoride sensing mechanism...
May 11, 2018: Journal of Computational Chemistry
Vahid Vatanpour, Ali Ghadimi, Atefeh Karimi, Alireza Khataee, Mohammad Ehsan Yekavalangi
Polypyrrole (PPy) coated raw and oxidized multiwalled carbon nanotubes (MWCNTs) nanocomposites were synthesized and used for hydrophilic modification of polyvinylidene fluoride (PVDF) ultrafiltration membranes. The prepared nanocomposites were characterized using XRD, FTIR and SEM techniques. The hydrophilicity of the fabricated membranes was evaluated using water contact angle measurements, where the mixed matrix membranes presented lower contact angle compared with the bare one. The performance results showed that the pure water flux increased from 152...
August 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Qian Zhang, Hua-Xu Zhu, Zhi-Shu Tang, Yong-Lan Pan, Bo Li, Ting-Ming Fu, Wei-Wei Yao, Hong-Bo Liu, Lin-Mei Pan
To investigate the feasibility of vapor permeation membrane technology in separating essential oil from oil-water extract by taking the Forsythia suspensa as an example. The polydimethylsiloxane/polyvinylidene fluoride (PDMS/PVDF) composite flat membrane and a polyvinylidene fluoride (PVDF) flat membrane was collected as the membrane material respectively. Two kinds of membrane osmotic liquids were collected by self-made vapor permeation device. The yield of essential oil separated and enriched from two kinds of membrane materials was calculated, and the microscopic changes of membrane materials were analyzed and compared...
April 2018: Zhongguo Zhong Yao za Zhi, Zhongguo Zhongyao Zazhi, China Journal of Chinese Materia Medica
Sherry Shiqian Gao, Kitty Jieyi Chen, Duangporn Duangthip, Edward Chin Man Lo, Chun Hung Chu
Hong Kong, as a special administrative region of the People’s Republic of China, is a metropolitan city in Asia with a population of approximately 7.4 million. This paper reflects the oral health care situation in Hong Kong. Water fluoridation was introduced in 1961 as the primary strategy for the prevention of dental caries. The fluoride level is currently 0.5 parts per million. Dental care is mainly provided by private dentists. The government’s dentists primarily serve civil servants and their dependents, with limited emergency dental service for pain relief offered to the general public...
May 11, 2018: Healthcare (Basel, Switzerland)
Marc Biver, Montserrat Filella
A completely selective method for electrochemical determination of very low concentrations (ngL-1 ) of niobium is presented. The method relies on the cathodic reduction of the pyrogallol red‑niobium complex at pH3. Virtually no sample preparation (apart from cation exchange) is required. The method is both free from interferences (particularly from Ta) and affordable. Time consuming preconcentration and separation procedures as well as the use of hydrofluoric acid, fluorides or problematic solvents are avoided...
February 15, 2018: Science of the Total Environment
Weiming Wu, Renliang Huang, Wei Qi, Rongxin Su, Zhimin He
Polyvinylidene fluoride (PVDF) membranes are limited in the field of oil-in-water emulsion treatment because the intrinsic hydrophobicity of PVDF can cause serious membrane fouling. Here, a superhydrophilic PVDF membrane (PVDF@PDA-GSH) was fabricated using a facile, versatile, mussel-inspired method. The pristine PVDF membrane was coated with dopamine under mild alkaline conditions by a dip-coating method, followed by addition of glutathione (GSH) via a simple reaction. GSH was successfully coated onto the membrane surface and confirmed by X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectrometry (EDX)...
May 11, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Reinert Verstraete, Heleen Sijbom, Jonas J Joos, Katleen Korthout, Dirk Poelman, Christophe Detavernier, Philippe F Smet
Traditional light sources, e.g. incandescent and fluorescent lamps, are currently being replaced by white light-emitting diodes (wLEDs) because of their improved efficiency, prolonged lifetime and environmental friendliness. Much effort has recently been spent to the development of Mn4+ -doped fluoride phosphors which can enhance the color gamut in displays and improve the color rendering index (CRI), luminous efficacy of the radiation (LER) and correlated color temperature (CCT) of wLEDs used for lighting...
May 11, 2018: ACS Applied Materials & Interfaces
Jiwon Eom, Gahyeon Lee, Dong Soo Lee
and theoretical studies were conducted to investigate low and non-linear responses in sub-micro molar-level suppressed ion chromatography with a hydroxide eluent. A calculated response was derived using experimentally determined detector effluent ion composition data and compared with measured experimental responses. The calibration curve was non-linear, and its slope varied considerably with different instrumental setups and operating conditions. The non-linearity of the solution conductivity response was determined by two acid-base equilibria of water and carbonic acid, and fluoride ion...
May 5, 2018: Journal of Chromatography. A
(no author information available yet)
No abstract text is available yet for this article.
May 11, 2018: British Dental Journal
Marie C Kirkegaard, Andrew Miskowiec, Michael W Ambrogio, Brian B Anderson
We have demonstrated the solid-state formation of a uranyl peroxide (UP) species from hydrated uranyl fluoride via a uranyl hydroxide intermediate, the first observation of a UP species formed in a solid-state reaction. Water vapor pressure is shown to be a driving factor of both the loss of fluorine and the subsequent formation of peroxo units. We have ruled out a photochemical mechanism for formation of the UP species by demonstrating that the same reaction occurs in the dark. A radiolytic mechanism is unlikely because of the low radioactivity of the sample material, suggesting the existence of a novel UP formation mechanism...
May 10, 2018: Inorganic Chemistry
Qiang Niu, Ping He, Shangzhi Xu, Ruling Ma, Yusong Ding, Lati Mu, Shugang Li
Emerging evidence has demonstrated that iron overload plays an important role in oxidative stress in the liver. This study aimed to explore whether fluoride-induced hepatic oxidative stress is associated with iron overload and whether grape seed proanthocyanidin extract (GSPE) alleviates oxidative stress by reducing iron overload. Forty Kunming male mice were randomly divided into 4 groups and treated for 5 weeks with distilled water (control), sodium fluoride (NaF) (100 mg/L), GSPE (400 mg/kg bw), or NaF (100 mg/L) + GSPE (400 mg/kg bw)...
2018: Journal of Toxicological Sciences
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