JBCS

Gas diffusion unit (GDU) in the proposed microflow analyzer and a fiagram for the determination of ammonium.

The present study details new synthetic methodology for the synthesis of cytotoxic nor-β-lapachone derivatives substituted at C-3 with pyrazole or carbohydrate moieties.

An efficient production of acetins from glycerol via a transesterification process using homogeneous or heterogeneous acid catalysis was performed.

This work describes the photolysis of pyrazosulfuron-ethyl in aqueous solution. Three tentative pathways are proposed according to the experimental results: cleavage of the sulfonylurea bridge, an intramolecular S_NAr reaction and photodesulfonylation which proceeds by a homolitic nitrogen-sulfur cleavage.

A carbon paste electrode chemically modified with multiwall carbon nanotubes in the presence of 3,4-dihydroxycinnamic acid was introduced as a homogeneous mediator for voltammetric determination of cysteamine in aqueous solution.

The focus of this work is the investigation of adsorption of the thiophene by Nb₂O₅ impregnated in ZSM-5 by means of kinetic and thermodynamic study of adsorption. The figure is for simple illustration of the process of adsorption.

This work presents an evaluation study of an ion selective field effect transistor (ISFET) electrode, compared to two glass electrodes containing different reference filling solutions, for measuring pH and acid number of several hydrous and anhydrous
fuel ethanol samples.

The levels of Hg, Pb, Cd, Ni, Co, Cu, Mn, Fe, Al and Zn in sediments from 13 fishing points of the Billings Reservoir were assessed. Only Fe and Co seemed natural occurrence, the other metals are possibly associated with anthropogenic sources. Figure shows (MPI) for all elements and (I_Geo) to Hg and Cu with indicative of sediments moderately to highly polluted.

With Rh/CeZrO₂ catalysts, DRIFTS (diffuse reflectance infrared spectroscopy) experiments of adsorbed CO showed the formation of different rhodium species on various supports. The effect of the metal dispersion, oxygen storage capacity and activity of these catalysts for the partial oxidation of methane were discussed.

Experimental design and response surface methodology were employed to evaluate the role (synergistic or antagonistic effects) of Fenton's reagents and to choose the better conditions that result in a higher efficiency of paraquat mineralization during
photo-Fenton process.

Rosmarinic acid is a potent antioxidant found in sage and in other plant species. Results from HPLC analysis may be affected by auto-oxidation during solvent extraction of plant material. Factorial designs of experiments were used for optimization of the sample preparation. The use of antioxidants in the extraction solvent prevented the analyte degradation producing more accurate results.

Four new modified eremophilanes (1-4) were isolated from P. cirsiifolium. 2α-Hydroxyadenostin B (4) showed anti-inflammatory activity (IC₅₀ 0.41 μmol per ear) and a neutrophil inhibition effect measured by the myeloperoxidase assay similar to that of indomethacin.

The oxidative dehydration of glycerol to acrylic acid was studied over V-impregnated zeolite Beta. Acrylic acid was observed with approximately 20% selectivity at 548 K.

Scanning electron microscopy (SEM) images of (a)Al(III)-chromotrope 2B coprecipitant with analytes; Cr(III), Pb(II) and Zn(II) (b) Fe(III)-chromotrope 2B coprecipitant with analytes; Cd(II), Mn(II), Pb(II) and Zn(II) are shown. The surface morphology of the precipitates is changed in the presence of chromotrope 2B reagent as well as analytes for both carriers.

N-acylhydrazones are particularly versatile for synthesis of compounds containing nitrogen. In this work, they were used as key substrates for the synthesis of 1,3,4-oxadiazolines biologically active.

The crosslinked chitosan-Fe(III) (Ch-FeCL) adsorbent was developed using Fe(III) immobilized on chitosan beads. After the drying process, the beads have a diameter of about 1 mm and are stable in air. The pH value for removal of As(III) and As(V) was 7.0. The adsorbent was successfully applied for the removal of As(III) and As(V) from natural water samples.

The antibacterial and antifungal activities of several chalcones were determined by the minimal inhibitory concentration against different microorganisms (Gram-positive and Gram-negative bacteria and fungi). Chemometric studies were carried out in order to identify a potential structure-activity relationship.

The present study describes that nor-β-lapachone derivatives exhibited pronounced cytotoxic effects against four human leukemia cell lines. Complex studies were conducted to clarify the mechanism of action related to the cytotoxic activity of these derivatives.

Drimenol and bicyclogermacrene were isolated from the essential oils of Drimys angustifolia. Antibacterial activity (MIC) of these isolated compounds as well as of their binary mixtures was evaluated. No synergism was observed.

A magnetically separable β-cyclodextrin (β-CD) was developed and used for oxidation of various alcohols. Water was used as the only solvent and NaOCl as a cheap and green oxidant. Facilitated recovery of β-CD and excellent efficiency for selective oxidation of alcohols were achieved.