Development of retention mechanism for the separation of carboxylic acids and inorganic anions in cryptand-based ion chromatography.

The ion-exchange and complex forming equilibria were quantitatively described and demonstrated in order to understand major factors in the control of selectivity in the analytical separation of carboxylic acids and inorganic anions in cryptand based ion chromatography. A complex retention model has been developed for the separation on a non-conventional IC column. Changes in retention are treated both theoretically and experimentally.

[Glucagon-like peptide-1 (GLP1) and the gastrointestinal tract. ].

Glucagon-like peptide-1 (GLP1) and their receptor agonists - beside their blood glucose lowering and central effects- affect also the gastrointestinal function in many respects. They slow down the stomach emptying, the motility of the small bowel and colon - this is the explanation for the "ileal brake" terminology -, stimulate the function of exocrine pancreatic acinar cells and increase amylase production. GLP1 receptor agonists belong to the defining tools of the blood glucose lowering therapy in type 2 diabetes.

High Performance Anion Chromatography of Gadolinium Chelates.

High performance anion chromatography (HPIC) method to separate ionic Gd chelates, [Formula: see text], [Formula: see text], [Formula: see text] and free matrix anions was developed. At alkaline pHs, polydentate complexing agents such as ethylene-diamine-tetraacetate, diethylene-triamine pentaacetate and trans-1,2-diamine-cyclohexane-tetraacetate tend to form stable Gd chelate anions and can be separated by anion exchange. Separations were studied in the simple isocratic chromatographic run over the wide range of pH and concentration of carbonate eluent using suppressed conductivity detection.

TiO₂-Mediated Photocatalytic Mineralization of a Non-Ionic Detergent: Comparison and Combination with Other Advanced Oxidation Procedures.

Triton X-100 is one of the most widely-applied man-made non-ionic surfactants. This detergent can hardly be degraded by biological treatment. Hence, a more efficient degradation method is indispensable for the total mineralization of this pollutant.

Solvent minimization in two-dimensional liquid chromatography.

An algorithm was developed for the minimization of consumption of organic solvent in comprehensive two-dimensional liquid chromatography (2DLC). It was shown that one can reach higher peak capacities only by using more eluent. The equilibration volume of the second dimension, however, did not affect the solvent consumption significantly.

[De Quervain thyroiditis. Corner points of the diagnosis].

Inflammatory disorders of the thyroid gland are divided into three groups according to their duration (acute, subacute and chronic). De Quervain's thyroiditis (also termed giant cell or granulomatous thyroiditis) is a subacute inflammation of the thyroid, which accounts for 5% of thyroid disorders. The etiology is unknown, it usually appears two weeks after an upper viral respiratory infection.

Degradation of industrial surfactants by photocatalysis combined with ozonation.

The efficiency of titanium dioxide-mediated photocatalytic degradation of pollutants can be enhanced by combination with another advanced oxidation procedure such as ozonation. Mineralization of hydroxy- and dihydroxybenzenesulfonate based on these methods, both individually and combined, was investigated by monitoring the total organic carbon content, sulfate concentration, pH, high-performance liquid chromatography as well as the absorption spectral changes. The mineralization efficiency of the combined procedure significantly exceeded the sum of those of the individual techniques.

High performance ion chromatography of transition metal chelate complexes and aminopolycarboxylate ligands.

A simple ion chromatographic method was developed for the separation of transition metal chelates (CuEDTA, CuDCTA, ZnEDTA, ZnDCTA) and free anionic complexing ligands (EDTA, DCTA) using alkaline carbonate eluents and conductivity detection. The complex equilibria and kinetic process of separations were studied in order to understand major factors in the control of selectivity and retention order of complex anions. A systematic study was applied to identify the additional peaks of the system as NaEDTA(3-), NaHEDTA(2-), Na(2)EDTA(2-), EDTA(4-)/HEDTA(3-), DCTA(4-)/HDCTA(-3).

[Verrucous carcinoma of the anal margin. The importance of adequate biopsy technique].

Buschke-Löwenstein tumor (verrucous carcinoma, giant condylomata) of the anal margin is a locally invasive, destructively growing carcinoma that does not metastasize. The lesions are rare despite the increased incidence of anal condylomata and anal carcinomas. Authors report a case of a 63-year-old woman suffering from verrucous carcinoma (Buschke-Löwenstein tumor) of the anal margin.

Boronic acid lectin affinity chromatography (BLAC). 3. Temperature dependence of glycoprotein isolation and enrichment.

In this paper, the effect of temperature is investigated on the performance of glycoprotein enrichment by boronic acid lectin affinity chromatography (BLAC). Wheat germ agglutinin and m-aminophenyl boronic acid containing stationary phases were evaluated individually and in a mixed mode using an automated liquid handling robot with an integrated 96-well plate temperature controller. Glycoaffinity enrichment of the model proteins of ribonuclease B and trypsin inhibitor was investigated in the presence of the non-glycosylated proteins of myoglobin (neutral) and lysozyme (basic) at a wide temperature range of 5-65 degrees C.

Equilibrium-based approach for prediction of matrix-related interferences in anion chromatography.

The retention behavior of low-concentration inorganic anions was studied systematically as a function of changing high matrix anion concentration. Stoichiometric retention model was developed for interpretation and prediction of matrix effects in ion chromatography. The model was tested and utilized for separation of low concentration (1-5 mg/l) bromate, bromide, chloride, nitrate, ethanesulfonate, and pentanesulfonate ions with carbonate buffer and hydroxide eluent in relatively wide ranges of sulfate matrix (>2000 mg/l).

Sample preparation for the analysis of complex carbohydrates by multicapillary gel electrophoresis with light-emitting diode induced fluorescence detection.

This paper evaluates various sample preparation methods for multicapillary gel electrophoresis based glycan analysis to support electrokinetic injection. First the removal of excess derivatization reagent is discussed. Although the Sephadex G10 filled multiscreen 96-well filter plate and Sephadex G10 filled pipet tips enabled increased analysis sensitivity, polyamide DPA-6S pipet tips worked particularly well.

High performance ion chromatography of haloacetic acids on macrocyclic cryptand anion exchanger.

A new high performance ion chromatographic method has been developed for the separation of the nine chlorinated-brominated haloacetic acids (HAAs) that are the disinfection by-products of chlorination of drinking water, using a macrocycle-based adjustable-capacity anion-exchange separator column (IonPac Cryptand A1). A gradient method based on theoretical and experimental considerations has been optimized in which 10 mM NaOH-LiOH step gradient was performed at the third minute of the analysis. The optimized method allowed us to separate the nine HAAs and seven possibly interfering inorganic anions in less than 25 min with acceptable resolution.

Retention controlling and peak shape simulation in anion chromatography using multiple equilibrium model and stochastic theory.

The stochastic theory of chromatography and an equilibrium based approach were used for the prediction of peak shape and retention data of anions. This attempt incorporating the potential advantages of two different chromatographic phenomena for analytical purposes. It is an integrated method to estimate kinetic and thermodynamic properties for the same chromatographic run of ions.

Retention profiles and mechanism of anion separation on latex-based pellicular ion exchanger in ion chromatography.

A retention model based on stoichiometric approach has been developed in order to describe analyte retention of anions on latex-based pellicular ion exchanger. The chromatographic process entails two stepwise and complex equilibria, first is ion-pair forming of analyte or eluent ion with ion-exchange sites under the effect of electrostatic forces due to the sulfonic layer behind the aminated functional groups of stationary phase. Second component is the ion-exchange between the analyte and eluent ions.

Ethylenediamine as eluent component in cation chromatography. Predictive and comparative study for analysis of alkaline earth ions.

The retention behaviour of alkaline earth cations was studied as a function of changing composition of acidified ethylenediamine eluent. The multiple eluent species retention model developed for separation of calcium, magnesium and strontium ions was utilized for determination of selectivity coefficients for sample and eluent ions. The suggested model accurately describes and predicts retention of analytes under elution conditions [0.

Tumor necrosis factor system in insulin resistance in gestational diabetes.

Objective: The aim of the study was to investigate the pathophysiological role of the tumor necrosis factor (TNF) system in insulin resistance in patients with gestational diabetes (GDM) and during the course of normal pregnancy.

Patients And Methods: Thirty women with GDM (16-39 gestational weeks), 35 healthy pregnant women (15 first, nine second and 11 third trimester) and 25 healthy age-matched non-pregnant women were studied. Serum TNF-alpha, and its soluble receptors 1 and 2 (sTNFR-1 and -2) were measured.