Search results for "sulfate"

Flow chemistry: Imidazole-based ionic liquid syntheses in micro-scale

2010

The quarternization of an N-atom in the 1-methyl-imidazole with different alkylating agents was investigated to form so-called Ionic Liquids. (3-Chloropropyl)-trimethoxysilane, 1-chlorobutane, diethyl sulfate and methyl trifluoromethanesulfonate were used as alkylating agents. Reaction kinetics range from very slow to instantaneous and the reaction heat from endothermal to extremely exothermal respectively. The reactions were performed under flow conditions using different types of microstructured reactors as well as pre-structurized reactants in the micro-scale. Unusual heat management with integrated heat pipes allow safer performing of highly exothermal reactions with comparably high thr…

Micellar versus hydro-organic mobile phases for retention-hydrophobicity relationship studies with ionizable diuretics and an anionic surfactant

2004

Abstract Logarithm of retention factors (log  k ) of a group of 14 ionizable diuretics were correlated with the molecular (log  P o/w ) and apparent (log  P app ) octanol–water partition coefficients. The compounds were chromatographed using aqueous–organic (reversed-phase liquid chromatography, RPLC) and micellar–organic mobile phases (micellar liquid chromatography, MLC) with the anionic surfactant sodium dodecyl sulfate (SDS), in the pH range 3–7, and a conventional octadecylsilane column. Acetonitrile was used as the organic modifier in both modes. The quality of the correlations obtained for log  P app at varying ionization degree confirms that this correction is required in the aqueou…

2016

Abstract. Cloud residues and out-of-cloud aerosol particles with diameters between 150 and 900 nm were analysed by online single particle aerosol mass spectrometry during the 6-week study Hill Cap Cloud Thuringia (HCCT)-2010 in September–October 2010. The measurement location was the mountain Schmücke (937 m a.s.l.) in central Germany. More than 160 000 bipolar mass spectra from out-of-cloud aerosol particles and more than 13 000 bipolar mass spectra from cloud residual particles were obtained and were classified using a fuzzy c-means clustering algorithm. Analysis of the uncertainty of the sorting algorithm was conducted on a subset of the data by comparing the clustering output with parti…

2012

Abstract. Measurements of the ambient aerosol were performed at the Southern coast of Spain, within the framework of the DOMINO (Diel Oxidant Mechanisms In relation to Nitrogen Oxides) project. The field campaign took place from 20 November until 9 December 2008 at the atmospheric research station "El Arenosillo" (37°5'47.76" N, 6°44'6.94" W). As the monitoring station is located at the interface between a natural park, industrial cities (Huelva, Seville) and the Atlantic Ocean, a variety of physical and chemical parameters of aerosols and gas phase could be characterized in dependency on the origin of air masses. Backwards trajectories were examined and compared with local meteorology to c…

Multicompartment Micelles with Adjustable Poly(ethylene glycol) Shell for Efficient in Vivo Photodynamic Therapy

2014

We describe the preparation of well-defined multicompartment micelles from polybutadiene-block-poly(1-methyl-2-vinyl pyridinium methyl sulfate)-block-poly(methacrylic acid) (BVqMAA) triblock terpolymers and their use as advanced drug delivery systems for photodynamic therapy (PDT). A porphyrazine derivative was incorporated into the hydrophobic core during self-assembly and served as a model drug and fluorescent probe at the same time. The initial micellar corona is formed by negatively charged PMAA and could be gradually changed to poly(ethylene glycol) (PEG) in a controlled fashion through interpolyelectrolyte complex formation of PMAA with positively charged poly(ethylene glycol)-block-p…

A Theoretical Study of the Wet Removal of Atmospheric Pollutants. Part II: The Uptake and Redistribution Of (NH4)2SO4Particles and SO2Gas Simultaneou…

1987

Abstract A theoretical model has been formulated which allows the processes which control the wet deposition of atmospheric aerosol particles and pollutant gases to be included in cloud dynamic models. The cloud considered in the model was allowed to grow by condensation and collision–coalescence, to remove aerosol particles by nucleation and impaction scavenging, and to remove pollutant gases by convective diffusion. The model was tested by using a simple air-parcel model as the dynamic framework. In this form the model was used to determine the fate of ammonium sulfate [(NH4)2SO4] particles and sulfur dioxide (SO2) gas as they became scavenged by cloud and precipitation drops. Special emp…

Mutations in the PDS Gene in German Families with Pendred’s Syndrome: V138F Is a Founder Mutation

2003

Pendred's syndrome, an autosomal-recessive condition characterized by congenital sensorineural hearing loss and goiter, is caused by mutations in the PDS gene. Located on chromosome 7q22-q31, it encodes a chloride-iodide transporter expressed in the thyroid, inner ear, and kidney. We investigated the PDS gene of six affected individuals from four unrelated families with Pendred's syndrome by direct sequencing. PDS mutations were identified in homozygous or compound heterozygous state in all six cases. A homozygous missense mutation leading to the amino acid substitution S133T was detected in a family of Turkish origin. The mutations found in the other affected individuals, who originate fro…

Description of the retention behaviour in micellar liquid chromatography as a function of pH, surfactant and modifier concentration

1997

Abstract Micellar liquid chromatography permits the elution of solutes of diverse polarity. One of the most outstanding advantages of the technique is its capability of predicting the retention with high accuracy, as a function of different experimental variables. The separation of a group of compounds is usually optimized by varying the concentrations of surfactant and modifier in the mobile phase. The pH is, however, for many solutes, a variable that should be considered in the description of their elution behaviour. A global model that takes into account, simultaneously, the concentrations of surfactant and modifier, and the pH as chromatographic variables, is proposed for ionizable solu…

Cultured Ito cells of rat liver express the alpha 2-macroglobulin gene.

1987

Ito cells were isolated from rat liver and kept in culture for up to 13 days. The capability of the Ito cells to synthesize a2-macroglobulin was analyzed at different times after isolation and by pulse-chase experiments. Newly synthesized a2-macroglobulin was determined by immunoprecipitation followed by sodium dodecyl sulfate/ polyacrylamide gel electrophoresis and fluorography. a2-Macroglobulin synthesis was hardly detectable in Ito cells and their media 3 days after plating. However, 5 - 11 days after the isolation of the cells, increasing amounts of a2-macroglobulin were synthesized. The results of pulse-chase experiments performed on day 7 showed that radioactively labeled a2-macroglob…

Sponge biosilica formation involves syneresis following polycondensation in vivo.

2011

Syneresis is a process observed during the maturation/aging of silica gels obtained by sol-gel synthesis that results in shrinkage and expulsion of water due to a rearrangement and increase in the number of bridging siloxane bonds. Here we describe how the process of biosilica deposition during spicule ("biosilica" skeleton of the siliceous sponges) formation involves a phase of syneresis that occurs after the enzyme-mediated polycondensation reaction. Primmorphs from the demosponge Suberites domuncula were used to study syneresis and the inhibition of this mechanism. We showed by scanning electron microscopy that spicules added to primmorphs that have been incubated with manganese sulfate …