Search results for " fluoride"
showing 10 items of 90 documents
Detection of a plant enzyme exhibiting chlorogenate-dependant caffeoyltransferase activity in methanolic extracts of arbuscular mycorrhizal tomato ro…
2012
When Glomus intraradices-colonised tomato roots were extracted in methanol at 6 degrees C, chlorogenic acid (5-caffeoylquinic acid), naturally present in the extract, was slowly converted by transesterification into methyl caffeate. The progress of the reaction could be monitored by HPLC. The reaction only occurred when the ground roots were left in contact with the hydro-alcoholic extract and required the presence of 15-35% water in the mixture. When the roots were extracted in ethanol, chlorogenic acid was transformed to ethyl caffeate in the same conditions. The reaction was also detected in Glomus mosseae-colonised tomato root extracts. It was also detectable in non-mycorrhizal root ext…
Analytical challenges to determine emerging persistent organic pollutants in aquatic ecosystems
2018
Emerging persistent organic pollutants (ePOPs) include polybrominated diphenyl ethers (PBDEs) and perfluorooctane sulfonyl fluoride/perfluorooctane sulfonate (POSF/PFOS), which are newly listed in the Stockholm Convention. Other ePOPs, which have not been regulated, include organophosphate flame retardants (PFRs), novel brominated flame retardants (NBFRs) and other perfluoroalkyl substances (PFASs). Often ePOPs data related to occurrence, toxicity, impact or environmental behavior are insufficient or inadequate because of the lack of proper analytical methods to obtain them. Thus, a critical review of the analytical procedures proposed in the last six years (2011–2017) for determining ePOPs…
Atom transfer radical polymerization with different halides (F, Cl, Br, and I): Is the process "living" in the presence of fluorinated initiators?
2016
Atom transfer radical polymerization (ATRP) is often used for grafting from fluorinated polymers. Nevertheless, the possibility to initiate an ATRP from a C-F functionality and the activity of the catalysts in the presence of fluoride anions are essentially unexplored. Therefore, we investigated the thermodynamics and kinetics of C-F bond activation by ATRP catalysts and compared it with other halide systems. The ATRP equilibrium constant was estimated to be small for the reaction between [CuITPMA]+ and benzyl fluoride (TPMA = tris(2-pyridylmethyl)- amine). However, [CuITPMA] + could react with the more active initiator diethyl fluoromalonate (DEFM). With DEFM as initiator and CuIBr/TPMA as…
Structure and Matrix Isolation Infrared Spectrum of Formyl Fluoride Dimer: Blue-Shift of the C−H Stretching Frequency
2006
Infrared spectroscopy (IR) of formyl fluoride (HCOF) dimer is studied in low-temperature argon and krypton matrixes. New IR absorptions, ca. 17 cm(-1) blue shifted from the monomer C-H stretching fundamental, are assigned to the HCOF dimer. The MP2/6-311++G calculations were utilized to define structures and harmonic frequencies of various HCOF dimers. Among the four optimized structures, the dimer having two C-H...O hydrogen bonds possesses strongest intermolecular bonding. The calculated harmonic frequencies of this dimer structure are shifted from the monomer similarly as observed in the experiment. Thus, we suggest that the experimentally observed blue shifted C-H bands belong to the di…
Evaluation of the relative thermoluminescence efficiency of LiF:Mg,Ti and LiF:Mg,Cu,P TL detectors to low-energy heavy ions
2013
Abstract The most popular types of LiF-based thermoluminescent (TL) detectors, LiF:Mg,Ti (MTS-N) and LiF:Mg,Cu,P (MCP-N), have been investigated, with respect to their dose (fluence) response and relative TL efficiency to different ion species. The detectors were irradiated using the nitrogen, iron, krypton and xenon ion beams, at energies ranging from 5.0 to 9.3 MeV/n. Supra- and sublinear response was found, for the MTS-N and MCP-N, respectively, similarly as observed for γ-rays. However, the level of nonlinearity of response of studied detectors is strongly reduced by increasing values of the ion ionization density (no supralinearity for Xe ions, for MTS-N, within calculated uncertaintie…
Effect of application time and concentration of silver diamine fluoride on the enamel remineralization
2021
Background Silver diamine fluoride has attracted attention because of its clinical success in arresting dental caries. Thus, the aim of this study was to evaluate the effect of different application times and concentrations of silver diamine fluoride (SDF) on deciduous tooth enamel remineralization. Material and Methods Blocks of deciduous tooth enamel were categorized into six groups of 11 each: 2 control groups: intact enamel, and demineralized enamel; 38% SDF and 30% SDF which were subdivided according to application times (1 and 3 min). The microhardness of samples was determined, and all groups except the intact enamel group were subjected to pH cycling to produce initial carious lesio…
Evaluation of diode laser application on chemical analysis and surface microhardness of white spots enamel lesions with two remineralizing agents
2020
Background To investigate the effect of diode laser application and two commercial remineralizing agents on the remineralization and surface microhardness of white spot enamel lesions. Material and methods Sixty specimens were prepared then equally divided into six groups (n=10/group), according to the diode laser and the two commercial remineralizing agents applied to demineralized enamel surfaces (APF gel and sodium fluoride NaF mousse) with or without diode Laser application as follows; Group A; control, Group B; diode Laser application, Group C; APF gel application, Group D; NaF mousse application, Group E; APF gel application + diode Laser, Group F; NaF mousse application+ diode Laser.…
CCDC 1425263: Experimental Crystal Structure Determination
2016
Related Article: T. Mäkelä, K. Rissanen|2016|Dalton Trans.|45|6481|doi:10.1039/C6DT00414H
CCDC 966356: Experimental Crystal Structure Determination
2015
Related Article: Alexander Jeremies, Ulrike Lehmann, Sina Gruschinski, Frederik Schleife, Michel Meyer, Vitaly Matulis, Oleg A. Ivashkevich, Marcel Handke, Karolin Stein, Berthold Kersting|2015|Inorg.Chem.|54|3937|doi:10.1021/acs.inorgchem.5b00123
CCDC 1901892: Experimental Crystal Structure Determination
2023
Related Article: Antti J. Neuvonen, Dimitris Noutsias, Filip Topić, Kari Rissanen, Tamás Földes, Imre Pápai, Petri M. Pihko|2019|J.Org.Chem.|84|15009|doi:10.1021/acs.joc.9b01980