Search results for "Fractionation"

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…

Fractionation of mercury in sediments during draining of Augusta (Italy) coastal area by modified Tessier method

2013

Abstract A modified Tessier method was applied to sediments dredged from Augusta (Italy) coastal area with the purpose of establishing the amount and the forms in which mercury is present in the different sediment fractions. The mercury fractionation was made by measuring the concentration of the metal ion on the solutions and directly on the sediment fractions obtained by sequential extraction. The measurements on the solutions as well as that on the solid fractions were carried out by using a Direct Mercury Analyser, DMA 80. This new instrument does not require sample preparation, and gives results comparable to those obtained with CV-AAS and ICP-MS and few minutes are necessary for each …

Interaction between N-terminal domain of H4 and DNA is regulated by the acetylation degree.

1998

Abstract To study whether the acetylation of one or more of the four acetylatable lysines of histone H4 affects its binding to DNA, we have designed a protection experiment with a model system consisting in phage lambda DNA as substrate, Stu I as restriction endonuclease and histone H4 with different degrees of acetylation as the protective agent. It can be deduced from the experimental data that the protection afforded by the histone is not dependent on the number of positive charges lost by acetylation. Thus, non-acetylated H4 and mono-acetylated H4 cause similar protection, while di-acetylation of the histone seems to be the crucial step in significantly weakening the interaction between…

Phenoloxidase-dependent cytotoxic mechanism in ascidian (Styela plicata) hemocytes active against erythrocytes and K562 tumor cells.

1997

The cytotoxic activity against rabbit erythrocytes (RE) and human K562 tumor cells by Styela plicata hemocytes was significantly related to the phenoloxidase (PO) which converts phenols to quinone and initiates the melanogenic pathway. The effector hemocyte population, separated in a Percoll density gradient band, enriched in a granulocyte type named "morula cells", was examined with RE in a hemocyte cytotoxic assay and plaque forming cell assay. Inhibition experiments with the copper chelating agents 1-phenyl-2-thiourea and tropolone, the substrate analogue sodium benzoate and sodium ascorbate support the notion that hemocyte cytotoxic activity is a PO-dependent mechanism. Treatments of he…

Electrophoretic separation of a class of nucleosomes enriched in HMG 14 and 17 and actively transcribed globin genes.

1980

Monomer nucleosomes from chick erythrocytes can be fractionated according to their electrophoretic mobility in (comparatively) high salt acrylamide gels. We show that the fractionation is based predominantly on differences in charge. The monomer heterogeneity persists even when the nucleosomes are trimmed down to 145 bp with Exo III or when H1 and H5 are removed. The slowest migrating monomers are associated with HMG 14 and 17; however, we do not believe that these proteins are entirely responsible for the altered mobility since the nucleosome heterogeneity persists even after removal of HMG 14 and 17. The DNA associated with the HMG 14 and 17 containing nucleosomes is shown to be enriched …

Characterization of Diesel Soot by Sedimentation Field Flow Fractionation

1990

Chemical and spectroscopic characteristics of the wood of Vitis vinifera cv. Sangiovese affected by esca disease.

2009

Chemical and spectroscopic analyses ((13)C cross-polarization-magic angle spinning NMR and attenuated total reflection Fourier transform infrared spectroscopies) were carried out on the wood of Vitis vinifera cv. Sangiovese with brown-red discoloration and black streaks caused by esca disease. The analyses of the brown-red wood revealed the destruction of hemicelluloses and noncrystalline cellulose as well as modifications in the pectic and ligninic wood fractions. The pectic fraction consisted of carbohydrates associated with polyphenols. The lignin fraction exhibited only a few changes in the aromatic systems and a partial demethylation, and it appeared to be associated with condensed phe…

Biomass Fractionation Using Emerging Technologies

2021

Improved resolution power of electrophoretic fractionation of DNA using a voltage gradient up and down application

2004

The improved resolution power of electrophoretic fractionation of DNA in a wide range of molecular masses is demonstrated using an "up and down" application of voltage gradient gel electrophoresis (VGGE). This application also allows separation of different DNA fragments which are poorly fractionated in conventional electrophoresis.

Isotopic fractionation due to N2 fixation in various grain legumes

2004

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