Search results for "Halogens"
showing 10 items of 24 documents
Contrast sensitivity and glare disability by halogen light after monofocal and multifocal lens implantation
2000
BACKGROUND—Standard examination of contrast sensitivity under conditions of glare disability is performed with incandescent light. A new halogen glare test that simulates glare as seen with oncoming vehicle headlights was used to measure glare disability in patients implanted with multifocal and monofocal intraocular lenses (IOLs). METHODS—28 patients with an average age of 69 years (SD 12 years) were implanted with a monofocal IOL (SI-40NB, Allergan) and 28 patients with an average of 66 years (12 years) were implanted with a refractive multifocal IOL (Array-SA-40N, Allergan). All patients were followed for 5 months postoperatively. Contrast sensitivity at four spatial frequencies (3, 6, 1…
Diffusion technique for the generation of gaseous halogen standards
2009
Abstract Halogens are known to play an important role in the tropospheric ozone-depletion chemistry and are of special interest because of their influence on the atmospheric oxidation capacity. In this paper, we investigate the application of a capillary diffusion technique for the generation of gaseous halogen standards like Br 2 , IBr, ICl and I 2 . The influence of capillary dimension (i.e. length and inner diameter), ambient pressure and headspace volume of the diffusion vessel on the test gas output has been evaluated. The experimental output rates are determined from the mass loss of the analyte vessel on a regular schedule and compared with their respective theoretical predictions. W…
Solid state anion–π interactions involving polyhalides
2013
The stabilization of polyhalides in the solid state with the support of electron-deficient pentafluorophenyl groups is described. Furthermore, a synthetic approach towards the sensitive tetraiodide dianion is described and ESI mass spectrometric evidence for its presence in solution is reported.
Formation of an unprecedented (CuBr)5 cluster and a zeolite-type 2D-coordination polymer: a surprising halide effect
2013
A unique pentanuclear cluster within a zeolite-type polymer ([Cu5(μ4-Br)(μ3-Br)2(μ2-Br)2](μ2-MeSPr)3)n (1; void space >81%) and a luminescent 1D ([Cu(μ3-I)]4(MeSPr)3)n polymer, 2, are formed when MeSPr reacts with CuBr and CuI.
Halogenated derivatives of boldine with high selectivity for alpha1A-adrenoceptors in rat cerebral cortex.
1999
The selectivity of 3-nitrosoboldine and different halogenated derivatives of boldine (3-bromoboldine, 3,8-dibromoboldine and 3-chloroboldine) for alpha1-adrenoceptor subtypes was studied by examining [3H]-prazosin competition binding in rat cerebral cortex. In the competition experiments [3H]-prazosin binding was inhibited completely by all the compounds tested. The inhibition curves displayed shallow slopes which could be subdivided into high and low affinity components. The relative order of affinity and selectivity for alpha1A-adrenoceptors was 3-bromoboldine = 3,8-dibromoboldine = 3-chloroboldineboldine3-nitrosoboldine. The competition curves for 3-bromoboldine remained shallow and biph…
Swimming pool water--fractionation and genotoxicological characterization of organic constituents.
2005
Swimming pool water treatment in general includes flocculation, sand filtration, and subsequent disinfection with chlorine. The continuous chlorination and input of organic material by bathers in combination with recirculation of the pool water leads to an accumulation of disinfection by-products (DBPs) in the water. Several DBPs have been identified as human carcinogens and are thought to cause allergic asthma. Therefore, the elimination of DBPs is one major aim of pool water treatment. Using membrane filtration as an alternative treatment technology, DBPs can be removed more efficiently than with conventional treatment. In this study membrane filtration and genotoxicity testing were appli…
Volcanic plume monitoring at mount Etna by diffusive(passive)sampling
2004
This paper reports the use of diffusive tubes in determining HF, HCI, and SO2 in the volcanic plume of Mount Etna in an attempt to highlight the potential of this method in studying volcanoes. In a first application a network of 18 diffusive tubes was installed on Etna's flanks, aimed at evaluating the atmospheric dispersion of the volcanic plume on a local scale. Results showed a monotonic decrease in volatile air concentrations with distance from the craters (HF from 0.15 to <0.003 μmol m-3 , HCl from 2 to <0.01 μmol m -3, and SO2 from 11 to 0.04 μmol m -3 ), revealing the prevalently volcanic contribution. Matching of SO2/HCl and HCl/HF volatile ratios with contemporaneous measurements a…
Halogen (Cl, F) release during explosive, effusive, and intrusive phases of the 2011 rhyolitic eruption at Cordón Caulle volcano (Chile)
2019
We investigate sulphur, chlorine and fluorine release during explosive, effusive and intrusive phases of the 2011 Cordon Caulle eruption, with a focus on halogen devolatilization. Petrological analysis shows halogen release to have been promoted by isobaric crystallization in slowly-cooled magma that was emplaced in a lava flow and sub-vent intrusion. Fluorine in particular mobilized only after extensive groundmass crystallization and incipient devitrification. By 2017, the gas emitted from vent-proximal fumaroles had hydrothermal compositions, with HCl/HF ratios decreasing with decreasing temperature. We estimate that the eruption could eventually emit up to 0.84 Mt of SO2, 6.3 Mt of HCl, …
Iodinatedortho-Carboranes as Versatile Building Blocks to Design Intermolecular Interactions in Crystal Lattices
2009
[EN] The crystal structures of numerous iodinated ortho-carboranes have been studied, which has revealed the diversity of intermolecular interactions that these substances can adopt in the solid state. The nature-mostly as it relates to hydrogen and/or halogen bonds-and relative strength of such interactions can be adjusted by selectively introducing substituents onto the cluster, thus enabling the rational design of crystal lattices. In this work we present the newly determined crystal structures of the following iodinated ortho-carboranes: 9-I-1,2-closo-C2B10H11, 4,5,7,8,9,10,11,12-I-8-1,2-closo-C2B10H4, 3,4,5,6,7,8,9,10,11,12-I-10,-1,2-closo-C2B10H2, 1-Me-8,9,10,12-I-4-1,2-closo-C2B10H7,…
Photoalignment and Surface-Relief-Grating Formation are Efficiently Combined in Low-Molecular-Weight Halogen-Bonded Complexes
2012
It is demonstrated that halogen bonding can be used to construct low-molecular-weight supramolecular complexes with unique light-responsive properties. In particular, halogen bonding drives the formation of a photoresponsive liquid-crystalline complex between a non-mesogenic halogen bond-donor molecule incorporating an azo group, and a non-mesogenic alkoxystilbazole moiety, acting as a halogen bond-acceptor. Upon irradiation with polarized light, the complex exhibits a high degree of photoinduced anisotropy (order parameter of molecular alignment > 0.5). Moreover, efficient photoinduced surface-relief-grating (SRG) formation occurs upon irradiation with a light interference pattern, with…