Search results for "Halogen"
showing 10 items of 434 documents
Probabilistic risk assessment of the exposure to polybrominated diphenyl ethers via fish and seafood consumption in the Region of Valencia (Spain)
2013
The study was carried out to estimate the dietary intake of polybrominated diphenyl ethers (PBDEs) in the Region of Valencia (Spain) in order to evaluate the resultant risk. The PBDE levels in fish and seafood (a total of 206 samples) were determined. Dietary intake was estimated using results of PBDE analyses in fish and seafood marketed in the Region of Valencia over the period 2007-2012 and data of the first Valencian Food Consumption Survey, conducted in 2010. Two scenarios were assumed for left-censored results: the lower-bound (LB) scenario, in which unquantified results (below the limit of quantification (LOQ)) were set to zero and the upper-bound (UB) scenario, in which unquantified…
Halogen and Hydrogen Bonded Complexes of 5-Iodouracil
2013
Three derivatives of 5-iodouracil were prepared, and their complexation properties, supplemented by 5-iodouracil under the same conditions, were studied with and without halogen bond acceptors in N,N-dimethylformamide, N,N-diethylformamide, N-methylformamide, formamide, dimethylsulfoxide, and water. The intermolecular halogen and hydrogen bonding interactions observed in the solid state were investigated using single crystal X-ray diffraction and quantum chemical calculations, and the acquired data were contrasted with bonding interactions previously reported for 5-iodouracil in the Cambridge Structural Database. It was found that the polarized iodine atom and the amidic NH functionality ac…
ChemInform Abstract: 2-Aryl-Substituted, Benzo-Anellated 5-Membered Heterocyclic Compounds as Potentially Active Substances for the Cardiovascular Sy…
2010
In the course of investigations on structure-activity relationships of calcium antagonists analogous to fostedil, a series of 2-aryl- and 2-arylvinyl-substituted 1,3-henzothiazoles and 1,3-benzoxazoles bearing a phosphonate group on the phenyl ring has been synthesized by cyclization, bromination, and subsequent Michaelis-Arbuzow reaction. Pharmacological investigations on isolated organs from guinea pigs revealed both negative inotropic effects and a relaxing action on smooth musculature; these activities were particularly pronounced in the 1,3-benzothiazole compound group.
2-Aryl-substituted, benzo-anellated 5-membered heterocyclic compounds as potentially active substances for the cardiovascular system: 1,3-Benzothiazo…
1992
In the course of investigations on structure-activity relationships of calcium antagonists analogous to fostedil, a series of 2-aryl- and 2-arylvinyl-substituted 1,3-henzothiazoles and 1,3-benzoxazoles bearing a phosphonate group on the phenyl ring has been synthesized by cyclization, bromination, and subsequent Michaelis-Arbuzow reaction. Pharmacological investigations on isolated organs from guinea pigs revealed both negative inotropic effects and a relaxing action on smooth musculature; these activities were particularly pronounced in the 1,3-benzothiazole compound group.
Electrochemically reduced titanocene dichloride as a catalyst of reductive dehalogenation of organic halides
2006
Abstract We have studied a reaction between the reduced form of titanocene dichloride (Cp 2 TiCl 2 ) and a group of organic halides: benzyl derivatives (4-X C 6 H 4 CH 2 Cl, X = H, NO 2 , CH 3 ; 4-X C 6 H 4 CH 2 Br, X = H, NO 2 , PhC(O); 4-X C 6 H 4 CH 2 SCN, X = H, NO 2 ) as well as three aryl halides (4-NO 2 C 6 H 4 Hal, Hal = Cl, Br; 4-CH 3 O-C 6 H 4 Cl). It has been shown that the electrochemical reduction of Cp 2 TiCl 2 in the presence of these benzyl halides leads to a catalytic cycle resulting in the reductive dehalogenation of these organic substrates to yield mostly corresponding toluene derivatives as the main product. No dehalogenation has been observed for aryl derivatives. Base…
Determining the efficiency of optical sources using a smartphone's ambient light sensor
2017
This work reports the use of a smartphone’s ambient light sensor as a valuable tool to study and characterize the efficiency of an optical source. Here, we have measured both luminous efficacy and efficiency of several optical sources (incandescent bulb and halogen lamp) as a function of the electric power consumed and the distance to the optical detector. The illuminance of LEDs as a function of the distance to the optical detector is characterized for different wavelength emissions. Analysis of the results confirms an inverse-square law of the illuminance with the detector–source distance and shows good agreement with values obtained by classical experiments. This experience will trigger …
Polybrominated methoxy diphenyl ethers (MeO-PBDEs) in fish and guillemot of Baltic, Atlantic and Arctic environments
2003
Arctic cod liver samples from Vestertana Fjord at the Arctic coast of Norway, salmon and guillemot samples from the Baltic Sea and the Atlantic Ocean, and salmon and lamprey larva samples from Kymijoki River in southern Finland were analysed for the occurrence of tri-, tetra- and pentabromomethoxy diphenyl ethers and their concentration levels were estimated. These compounds have previously been identified by other research groups in salmon, seal and dolphin samples. The aim of this study was to find out a possible temporal trend in the concentrations of these compounds in the cod liver samples from years 1987-1998 and to investigate the possible spatial differences in the concentrations in…
Contaminants of emerging concern in freshwater fish from four Spanish Rivers.
2019
This study investigated the occurrence of 135 contaminants of emerging concern (CECs) – pharmaceuticals, pesticides, a set of endocrine disrupting compounds (EDCs) (parabens, bisphenols, hormones, triazoles, organophosphorus flame retardants and triclosan), UV-filters, perfluoroalkyl substances (PFASs) and halogenated flame retardants (HFRs) – in 59 fish samples, collected in 2010 in 4 Spanish Rivers (Guadalquivir, Júcar, Ebro and Llobregat). Of the 135 CECs, 76 including 8 pharmaceuticals, 25 pesticides, 10 EDCs, 5 UV-filters, 15 PFASs and 13 HFRs were detected. Pharmaceuticals were the less frequently found and at lower concentrations. Pesticides, EDCs, UV-filters, PFASs and HFRs were det…
Reactivity of SiCl and SiF groups in SiO2 glass with mobile interstitial O2 and H2O molecules
2007
Reactions of common network-bound halogens in synthetic SiO2 glass, SiCl and SiF groups, with interstitial O2 and H2O molecules incorporated by thermally annealing were studied. It was found that the chemical properties are distinctly different between SiCl and SiF groups. SiCl groups react with interstitial O2 and H2O to form interstitial Cl2 and HCl, respectively. In contrast, formation of interstitial F2 and HF due to the reaction of SiF groups with interstitial O2 and H2O is not observed. The reactivity of SiCl and SiF groups is in accord with the properties and thermodynamic data of their respective analogous compounds, SiCl4 and SiF4.
Fluorinated glycosyl amino acids for mucin-like glycopeptide antigen analogues.
2010
The aberrant glycosylation profiles of mucin glycoproteins on epithelial tumour cells represent attractive target structures for the development of immunotherapy against cancer. Mucin-type glycopeptides have been successfully investigated as molecularly defined vaccine prototypes for triggering humoral immunity but are susceptible to rapid in vivo degradation. As a potential means to enhance the bioavailabilities of the antigenic structures, hydrolysis-resistant carbohydrate analogues with fluorine substituents at positions C6, C2' and C6' were synthesised and incorporated into the tandem repeat sequence of the mucin MUC1. The resulting pseudo-glycopeptides can be used to elucidate the effe…