Search results for "PRECIPITATION"

Determination of ochratoxin A in beer marketed in Spain by liquid chromatography with fluorescence detection using lead hydroxyacetate as a clean-up …

2005

Abstract A new sample treatment for liquid chromatographic analysis of ochratoxin A (OTA) in beer is proposed. Degassed beer is mixed with lead hydroxyacetate, which precipitates some bulk components but does not remove OTA. The precipitate is separated and the acidified liquid is extracted with chloroform. The solvent is evaporated and the residue is dissolved in mobile phase (acetonitrile–water, 40:60, v/v; acidified at pH 3.0 with phosphoric acid) and separated by liquid chromatography using fluorescence detection. The limit of detection was 0.005 ng/ml. The average recovery rate and the average RSD of recovery in the spiking level range 0.01–0.5 ng/ml were 95.5% and about 5%, respective…

Synthesis and assembly of virus-like particles of human papillomaviruses type 6 and type 16 in fission yeast Schizosaccharomyces pombe.

1995

AbstractWe have synthesized capsid proteins of human papillomavirus types 6 (HPV 6) and 16 (HPV 16) in fission yeast Schizosaccharomyces pombe and produced virus-like particles (VLP). The capsid proteins were localized in the nucleus by indirect immunofluorescence and cell fractionation analyses. The VLP were produced in both yeast clones synthesizing L1 alone and L1/L2 and purified by sulfato-cellulofine chromatography. Electron microscopic examination showed that these VLP were similar in structure to native HPV particles. Two HPV 16 L1 variants (16 B27L1 and 16 T3L1), isolated from benign cervical samples, produced many more (68- and 14-fold) VLP than the prototype L1 (16 PL1) derived fr…

Nuclear and cytoplasmic interaction of pRb2/p130 and ER-β in MCF-7 breast cancer cells

2006

Estrogens exhibit important biological functions and influence several pathological processes of hormone-dependent diseases. The biological actions of estrogens require their interaction with two estrogen receptors (ER-alpha and ER-beta), which are ligand-dependent transcription factors. ER-alpha and ER-beta exhibit distinct tissue expression patterns as well as show different patterns of gene regulation. In addition, it has been suggested that ER-beta works as a counter partner of ER-alpha through inhibition of the transactivating functions of ER-alpha. For instance, ER-beta seems to play a different role in breast tumorigenesis than ER-alpha, as ER-beta decreased expression in breast canc…

Expression of a mutant HSP110 sensitizes colorectal cancer cells to chemotherapy and improves disease prognosis

2011

Heat shock proteins (HSPs) are necessary for cancer cell survival. We identified a mutant of HSP110 (HSP110ΔE9) in colorectal cancer showing microsatellite instability (MSI CRC), generated from an aberrantly spliced mRNA and lacking the HSP110 substrate-binding domain. This mutant was expressed at variable levels in almost all MSI CRC cell lines and primary tumors tested. HSP110ΔE9 impaired both the normal cellular localization of HSP110 and its interaction with other HSPs, thus abrogating the chaperone activity and antiapoptotic function of HSP110 in a dominant-negative manner. HSP110ΔE9 overexpression caused the sensitization of cells to anticancer agents such as oxaliplatin and 5-fluorou…

Convective and stratiform precipitation: A PCA-based clustering algorithm for their identification

2020

The increasing occurrence of flood events in some areas of the Southern Mediterranean area (e.g., Sicily), over the last few years, has contributed to raising the importance of characterizing such events and identifying their causes.

Phosphoproteinphosphatase activity in sea urchin embryos

1964

Si e studiata l'attivita fosfoproteinfosfatasica in omogenati totali di uova ed embrioni diParacentrotus lividus e diArbacia lixula. La reazione ha un optimum a pH acido, e stimolata da K+ e Na+ ed e inibita da Ca++ e Mg++. L'attivita enzimatica aumenta tra la fecondazione e lo stadio a 64 blastomeri; in seguito rimane costante fino a blastula con mesenchima; quindi generalmente decresce.

Expression of the human complement C8 subunits is independently regulated by interleukin 1β, interleukin 6, and interferon γ

1998

The eighth component of human complement (C8) is composed of two subunits which are products from three separate genes. The alpha-gamma- and the beta-subunit of C8 are expressed independently, and are part of the membrane attack complex. C8 is primarily synthesized in the liver. It has been shown in previous studies that the human hepatoma cell line HepG2 constitutively expresses C8, and thus is a suitable model system for studying C8 biosynthesis in vitro. Expression is modulated by the cytokines IL-1 beta, IL-6 and IFN-gamma. The effect of the different cytokines on the expression of these subunits was examined using biosynthetical labelling and immunoprecipitation methods. C8 alpha-gamma…

Purification of a nuclease from human serum.

1981

The purification procedure for a nuclease from human serum is described. It includes ammonium sulfate precipitation, chromatography on DEAE-Sephadex and on Sephacryl-S 200, and preparative electrophoresis. The enzyme, purified about 2000-fold, is homogeneous in a sodium dodecyl sulfate electrophoretic system, where it has a mol. wt of 78,000. The pH optimum lies around pH 6.5; it is a sugar-nonspecific endonuclease.

Exploring the high-pressure behavior of the three known polymorphs of BiPO4: Discovery of a new polymorph

2015

We have studied the structural behavior of bismuth phosphate under compression. We performed x-ray powder diffraction measurements up to 31.5 GPa and ab initio calculations. Experiments were carried out on different polymorphs: trigonal (phase I) and monoclinic (phases II and III). Phases I and III, at low pressure (P < 0.2-0.8 GPa), transform into phase II, which has a monazite-type structure. At room temperature, this polymorph is stable up to 31.5 GPa. Calculations support these findings and predict the occurrence of an additional transition from the monoclinic monazite-type to a tetragonal scheelite-type structure (phase IV). This transition was experimentally found after the simultaneo…

2020

The complex surface geometries of hailstones affect their fall behavior, fall speeds, and growth. Systematic experimental investigations on the influence of the number and length of lobes on the fall velocity and the drag coefficient of hailstones were performed in the Mainz vertical wind tunnel to provide relationships for use in numerical models. For this purpose, 3D prints of four artificial lobed hailstone models as well as spheres were used. The derived drag coefficients show no dependency in the Reynolds number in the range between 25,000 and 85,000. Further, the drag coefficients were found to increase with increasing length of lobes. All lobed hailstones show higher or similar drag …