Search results for "ion exchange resins"

PURINE AND PYRIMIDINE NUCLEOTIDES IN THE BRAIN OF NORMAL AND CONVULSANT RATS

1969

— Purine and pyrimidine nucleotides were measured in the brain of normal and electroshocked rats after chromatographic separation on ion-exchange resin of mono-, di- and tri-phosphorylated derivatives. CMP, IMP and NAD did not show any significant quantitative change. Adenine nucleotides showed an abrupt change followed by a rapid return to the control value. GTP was the only purine nucleotide exhibiting a relatively slow return to its starting concentration. The greatest percentage increase after electroshock was observed in UMP, which returned to its control value only after 5 min; UDPCoenzymes (i.e. UDPA plus UDPG) showed a relatively small drop during the development of the seizure and …

Isolation of organic material from water.

1985

Cationic lipide mediated transfer of c-abl and bcr antisense oligonucleotides to immature normal myeloid cells: Uptake, biological effects and modula…

1996

Uptake and biochemical and biological effects of antisense oligodeoxynucleotides (ODN) specific for c-abl and bcr genes were studied in normal immature myeloid cells. CD34-positive cells were purified by positive and negative selection and cultured in liquid culture for 7 days. These cells were then incubated with ODNs, either alone or in combination with cationic lipids. The uptake of ODNs was enhanced by the use of cationic lipids. In addition, very low concentrations of ODNs in combination with cationic lipids were capable of specifically inhibiting the expression of the c-abl gene. In contrast, no effects were seen on the expression of bcr. However, despite the effective blocking of c-a…

Desulfurization: Critical step towards enhanced selenium removal from industrial effluents

2017

Abstract Selenium (Se) removal from synthetic solutions and from real Flue Gas Desulfurization (FGD) wastewater generated by a coal-fired power plant was studied for the first time using a commercial iron oxide impregnated strong base anion exchange resin, Purolite ® FerrIX A33E. In synthetic solutions, the resin showed high affinity for selenate and selenite, while sulfate exhibited a strong competition for both oxyanions. The FGD wastewater investigated is a complex system that contains Se (∼1200 μg L −1 ), SO 4 2− (∼1.1 g L −1 ), Cl − (∼9.5 g L −1 ), and Ca 2+ (∼5 g L −1 ), alongside a broad spectrum of toxic trace metals including Cd, Cr, Hg, Ni, and Zn. The resin performed poorly again…

N-Propyl-N′-2-pyridylurea-modified silica as mixed-mode stationary phase with moderate weak anion exchange capacity and pH-dependent surface charge r…

2018

Herein, we present a novel silica-based stationary phase modified with N-propyl-N'-2-pyridylurea selector. Due to the weakly basic properties of the pyridine selector and the presence of residual silanols after selector immobilization, a zwitterionic surface with a pI observed at approximately pH 5.5 was measured by electrophoretic light scattering in pH-dependent ζ-potential determinations. The capability of the new N-propyl-N'-2-pyridylurea-modified silica to serve as mixed-mode stationary phase was investigated. For this purpose, it was characterized under RP and HILIC conditions using test mixtures. Subsequent classification of this stationary phase in comparison to in-house and commerc…

Maturation of a Key Resource – The Germanium-68/Gallium-68 Generator: Development and New Insights

2011

(68)Ge/(68)Ga radionuclide generators have been investigated for almost fifty years, since the cyclotron-independent availability of positron emitting (68)Ga via the (68)Ge/(68)Ga system had always attracted researches working in basic nuclear chemistry as well as radiopharmaceutical chemistry. However, it took decades and generations of research (and researchers) to finally reach a level of (68)Ge/(68)Ga radionuclide generator designs adequate to the modern requirements of radiometal labelling chemistry. Nevertheless, most of the existing commercial generator systems address aspects of (68)Ge breakthrough and safe synthesis of (68)Ga radiopharmaceuticals by adopting eluate post-processing …

Adsorption of methotrexate and calcium leucovorin onto cholestyramine in vitro.

2003

Abstract Methotrexate (MTX), an antimetabolite of folic acid, is a drug widely used in the treatment of different types of cancer. When high doses are administered, it is necessary to interrupt its action by administering calcium leucovorin (CaL). The main pathway of MTX and CaL elimination in humans occurs through the kidney, but about 10% is excreted in the faeces via the bile. Drugs, foods and sorbents in intestinal lumen modify MTX and CaL reabsorption. Individual and simultaneous studies on the adsorption of MTX and CaL from aqueous phosphate buffer by cholestyramine were carried out in order to calculate the adsorption process of MTX and CaL to cholestyramine, and to characterize the …

Analysis of neuropeptide Y and its metabolites by high-performance liquid chromatography-electrospray ionization mass spectrometry and integrated sam…

2000

A novel restricted access cation exchanger with sulphonic acid groups at the internal surface was proven to be highly suitable in the sample clean up of peptides on-line coupled to HPLC-electrospray ionization (ESI)-MS. Neuropeptide Y (NPY) and several of its fragments in plasma were subjected to the sample clean-up procedure. The peptides were eluted by a step gradient from the restricted access column, applying 10 mM phosphate buffer pH 3.5 from 5 to 20% (v/v) of acetonitrile with 1 M NaCl and transferred to a Micra ODS II column (33x4.6 mm). The separation of the peptides and their fragments was performed by a linear gradient from 20 to 60% (v/v) acetonitrile in water with 0.1% formic ac…

Potent Aroma Compounds of Two Red Wine Vinegars

2000

Gas chromatography olfactometry (GCO) was used to determine key aroma compounds of two red wine vinegars. Sensory analysis was performed to choose the best neutralization agent of acetic acid (NaOH or MgO) and to test representativeness of four extracts obtained by different methods (dichloromethane extraction, XAD-2, mixture of XAD-2 and XAD-7, and Extrelut resins extraction). Neutralization with NaOH followed by dichloromethane extraction was selected to extract volatile compounds of vinegars. Key odorant compounds were determined by GCO based on detection frequency with 13 people. In the two red wine vinegars, 13 odors were perceived by at least 70% of the panelists, and 8 compounds amon…

Scandium-44: Benefits of a Long-Lived PET Radionuclide Available from the 44Ti/44Sc Generator System

2011

(44)Ti/(44)Sc radionuclide generators are of interest for molecular imaging. The 3.97 hours half-life of (44)Sc and its high positron branching of 94.27% may stimulate the application of (44)Sc-labeled PET radiopharmaceuticals. This review describes the current status of (44)Ti production, (44)Ti/(44)Sc radionuclide generator development, post-processing of generator eluates towards medical application, identification of ligands adequate to Sc(III) co-ordination chemistry, proof-of-principle labeling of (44)Sc-DOTA-octreotides, investigation of in vitro and in vivo parameters, and initial applications for molecular imaging - both in small animals and humans.