Search results for "Sorbent"
showing 10 items of 635 documents
Expanding the application of stir bar sorptive-dispersive microextraction approach to solid matrices: Determination of ultraviolet filters in coastal…
2018
This work describes a new method for the determination of organic compounds in solid samples based on the equilibrium desorption of the analytes in an aqueous phase followed by stir bar sorptive-dispersive microextraction (SBSDME). Sand samples, contaminated with UV filters due to bathing and recreational activities, were dispersed in an aqueous medium by using a coated stir bar with CoFe2O4@oleic acid magnetic nanoparticles. The UV filters were physically desorbed from the surface of the sand particles and rapidly adsorbed on the hydrophobic coating of the nanoparticles, which were retrieved by means of their magnetism after stopping the stirring. In this manner, both preconcentration of t…
Cleaning sorbents used in matrix solid-phase dispersion with sonication: Application to the estimation of polycyclic aromatic hydrocarbons at ng/g le…
2012
This study shows that ultrasonic assisted extraction is a good practise for removing impurities from sorbents used for matrix-solid phase dispersion (MSPD). A previous washing of the sorbent with an organic solvent or mixture of solvents eliminates part of the interferences, but this treatment is not enough for the quantification of PAHs at ng/g levels. It is demonstrated that the determination of traces of polycyclic aromatic hydrocarbons (PAHs) in solid samples processed by matrix-solid phase dispersion (MSPD) may be severely affected by the presence of sorbent impurities. Different extraction solvents and sonication conditions have been tested, and on the basis of the results obtained a …
Treatment of giardiasis reverses "active" coeliac disease to "latent" coeliac disease.
2001
In patients with coeliac disease, a regression of intestinal damage without a gluten-free diet is a very rare event. We describe a young child with diarrhoea, intestinal mucosa atrophy and positive serum anti-endomysial and anti-tissue transglutaminase (anti-tTG) antibodies during intestinal giardiasis infection. He showed normal intestinal mucosa architecture and negative anti-endomysial and anti-tTG antibodies after his giardiasis was cured, although he continued to assume a normal diet. Re-evaluations on a 6-monthly basis showed that he was symptom free, and all haemato-chemical parameters were within normal limits. Three years after the initial diagnosis, a third intestinal biopsy showe…
Effects of primary- and secondary-treated bleached kraft mill effluents on the immune system and physiological parameters of roach.
2000
The present study was designed to examine, whether, effluents from a modern pulp and paper mill using elemental chlorine-free/total chlorine-free (ECF/TCF) bleaching, exert effects on the immune system of fish and, in addition, to relate these findings to physiological parameters known to be affected by bleached kraft-mill effluents (BKME). Roach (Rutilus rutilus) were exposed in laboratory conditions to primary- or secondary-treated effluent from a pulp and paper mill. In order to study their capability to respond to foreign antigens they were immunised with bovine gamma-globulin (BGG) prior to exposure. The number of anti-BGG antibody-secreting cells (ASC) and the number of immunoglobulin…
Enhanced immunogenicity of multivalent MUC1 glycopeptide antitumour vaccines based on hyperbranched polymers.
2015
Enhancing the immunogenicity of an antitumour vaccine still poses a major challenge. It depends upon the selected antigen and the mode of its presentation. We here describe a fully synthetic antitumour vaccine, which addresses both aspects. For the antigen, a tumour-associated MUC1 glycopeptide as B-cell epitope was synthesised and linked to the immunostimulating T-cell epitope P2 derived from tetanus toxoid. The MUC1-P2 conjugate is presented multivalently on a hyperbranched polyglycerol to the immune system. In comparison to a related vaccine of lower multivalency, this vaccine exposing more antigen structures on the hyperbranched polymer induced significantly stronger immune responses in…
A comparative study of the incorporation of a 1,6-beta-glucan and an O-glycosylated protein epitope into the cell wall of Candida albicans.
1996
The topological distribution of two epitopes in the cell wall of Candida albicans, the kinetics of their incorporation into the regenerating protoplast wall, and the effect of different antibiotics upon their incorporation and localization have been studied. To do so, two monoclonal antibodies that react against an O-glycosylated mannoprotein (1B12) and against a 1,6-beta-glucan epitope (JRR1) were used. The results show that the JRR1 epitope is localized in an internal layer of the cell wall, in contrast to the 1B12 epitope, which is superficial, and that the incorporation of the JRR1 epitope into walls of regenerating protoplasts precedes that of the 1B12 epitope. The JRR1 epitope is norm…
Darba vides gaisa piesārņojuma novērtējums krāsošanas procesā ar gāzu hromatogrāfijas metodi
2015
Darba vides gaisa piesārņojuma novērtējums krāsošanas procesā ar gāzu hromatogrāfijas metodi. Cercina A., zinātniskie vadītāji - Rīgas Stradiņa universitātes Higiēnas un arodslimību laboratorijas vadošais pētnieks, Dr. med. Baķe M. Ā. un Latvijas Universitātes vadošais pētnieks Dr. Chem. Nakurte I. Maģistra darbs, 52 lappuses, 21 attēli, 9 tabulas, 31 literatūras avoti, 17 pielikumi. Latviešu valodā. Darba teorētiskajā daļā apkopota informācija par GOS ietekmi uz veselību, apskatīti dažādi paraugu ņemšanas veidi un sorbcijas materiāli. Apkopotas populārākās GOS koncentrāciju noteikšanas metodes. Darbā ir veikta gaistošo organisko savienojumu koncentrācijas gāzu hromatogrāfiska noteikšana da…
Polyalbumin receptors, hepatitis B surface antigen (HBsAg), and HBsAg/IgM complexes in HBsAg positive patients with and without delta superinfection.
1985
Receptors for polymerized human albumin are found at high litres during high-level hepatitis B virus (HBV) replication and in small amounts in chronic low-level infection. Complexes between hepatitis B surface antigen (HBsAg) and IgM without specificity for HbsAg are expressed in a pattern similar to that of receptors. Anti-albumin antibodies could be involved in their formation. Delta infection depresses the synthesis of gene products of HBV. To assess whether delta modifies the expression of receptors on HBsAg and the level of HBsAg/IgM complexes, and if anti-albumin antibodies are actually part of the complex, we tested sera from 86 subjects with acute and chronic HBV infection. Our find…
Racēmisko 4-aizvietoto pirolidīn-2-ona atvasinājumu sadale uz polisaharīdu bāzes pārklātiem hirāliem sorbentiem
2017
Darbā analizēti literatūras avoti par enantiomēru sadali, izmantojot augsti efektīvo šķidrumu hromatogrāfiju uz polisaharīdu bāzes pārklātiem hirāliem sorbentiem. Eksperimentālajā daļā tika veikta 15 hirālu 4-aizvietotu pirolidīn-2-onu atvasinājumu enantiomēru analīze uz sešiem polisaharīdu bāzes pārklātiem hirāliem sorbentiem, izmantojot dažādas mobilās fāzes. Noskaidrots, ka enatiomēru sadale ir atkarīga gan no hirālā sorbenta dabas, gan no mobilās fāzes organiskā modifikatora. Labākā sadale sasniegta uz hirāliem sorbentiem, kas veidoti uz amilozes bāzes (Lux Amylose-1 un Lux Amylose-2).
Functional incorporation of green fluorescent protein into hepatitis B virus envelope particles
2004
AbstractThe envelope of hepatitis B virus (HBV), containing the L, M, and S proteins, is essential for virus entry and maturation. For direct visualization of HBV, we determined whether envelope assembly could accommodate the green fluorescent protein (GFP). While the C-terminal addition of GFP to S trans-dominant negatively inhibited empty envelope particle secretion, the N-terminal GFP fusion to S (GFP.S) was co-integrated into the envelope, giving rise to fluorescent particles. Microscopy and topogenesis analyses demonstrated that the proper intracellular distribution and folding of GFP.S, required for particle export were rescued by interprotein interactions with wild-type S. Thereby, a…