JBCS

The occurrence of azafluorenone alkaloids is rare and restricted to the Annonaceae family. In this study, the isolation of the alkaloid 5,8-dimethoxy-7-hydroxy-1-methyl-4-azafluoren-9-one and the megastigman (–)-(5R*, 6S*)-megastigman-3-one-10,7-olide from aerial parts of Unonopsis lindmanii (Annonaceae) is described.

This method can determine the profile of amino acids in human urine, in which alterations characterize cystinuria, an inborn error of metabolism. The earlier this alteration is detected in a newborn, the lower the chances of further health damage.

A low cost flow analysis setup employing multicommutation process for photometric determination of alantoin in soybean was developed employing a LED based photometer. Profitable features such as low reagent consumption and low volume of waste generation were achieved.

Compounds of strontium (SrO + SrCO₃ + Sr(OH)₂) can efficiently catalyze the transesterification reaction of babassu and castor oils as well as a mixture of these oils. This method can greatly contribute to the settling of the transesterification process since it is more industrially satisfactory.

DDT (1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane) and its derivatives showed good AutoDock Vina affinity values with several proteins involved in the insulin signaling pathway, suggesting this pesticide may modulate biochemical mechanisms, eventually explaining the reported relationship between exposure to this chemical and diabetes prevalence.

Thermo-óptical analysis (TOA) images at 100x magnification of (a) efavirenz, (b) lamivudine and (c) mixture. Three images in different temperatures were shown for each pure drug and six for the mixture.

This work describes the synthesis of a novel 3-(pyrimidinyl)propanoate series from versatile precursors 7,7,7-trihalo-4-methoxy-6-oxo-4-heptenoates obtained from renewable levulinic acid. These new derivatives are promising candidates for the treatment of different nervous system diseases.

The fabrication and performance characteristics of three novel potentiometric sensors for the determination of oxeladin citrate are described. The sensors are based on the oxeladin-phosphotungstate ion associate as the electroactive material and dibutyl phthalate as solvent mediator.

Monomer elution and water absorption from, or into, copolymers show the same dependence with the degree of conversion of the photopolymerization processes.

A series of lanthanide compounds containing one to three dibenzoylmethanate (DBM) ligands were synthesized and studied by luminescence spectroscopy. The abnormally high luminescence intensity exhibited by the less substituted Tb³⁺-DBM compounds was investigated and rationalized in terms of intramolecular ligand-to-metal energy transfers.

The new clerodane diterpene methyl 3-oxo-12-epibarbascoate was isolated from the stem barks of Croton urucurana together with the known diterpene methyl 12-epibarbascoate. Their structures were identified by spectroscopic techniques and the structure of 3-oxo-12-epibarbascoate was confirmed by X-ray diffraction. Graphical abstract adapted from the site http://www.tropicos.org/Image/52765, Tropicos Missouri Botanical Garden, July 11, 2012. The license terms are found at http://creativecommons.org/licenses/by-nc-sa/3.0/deed.en.

The response of poly(thiophene) to the impact of electron and photon beams at different energies was investigated. The mechanism of formation of the principal ionic species was elucidated by the ion desorption yield analysis. The effect of the thickness of the films on the desorption process was investigated by photodesorption analysis.

A novel electrochemical sensing platform for phloroglucinol was fabricated with graphene oxide and iron hydroxide colloid. Due to the high surface area and the excellent electrical conductivity of the nanohybrid, the prepared electrochemical sensor has preeminent electrocatalytic activity towards the oxidation of phloroglucinol.

The use of pesticides in rice cultivation in flooded paddy fields generates great environmental impact and new methods for simultaneous determination of pesticides and metabolites are required.

The proposed method avoids using chlorinated solvents and expensive apparatus that are commonly used in other extraction methods. This method is very simple and suitable for extraction of organic pollutants from sediment samples.

Comprehensive two-dimensional gas chromatography-flame ionization detection (GCxGC-FID) combined with multivariate analysis was used to differentiate Brazilian and Venezuelan gasoline samples.

Complex-plane plots for glassy carbon electrode modified with a ruthenium-based hexacyanoferrate film at pH 1.5 in the presence and absence of ethanol at different applied potentials vs. Ag|AgCl|KCl_sat. Inset figure: electrode in the absence of ethanol.

The present work reports a new analytical method for determination of hydrazine based on photoelectrocatalytic oxidation of TiO₂ film modified titanium foil electrode (Ti/TiO₂). This process was performed using Ti/TiO₂ photoelectrode fabricated with anodic oxidation of Ti foil electrode.

Isolation, characterization and cytotoxicity of a new triterpene (ficusonic acid) from the roots of Maytenus royleana plant.

A short chain alcohol aqueous two-phase system (ATPS) coupled with high performance liquid chromatography (HPLC) was developed to extract and analyse chloramphenicol (CAM) in livestock meat samples.

Hydrogen bond interaction between the naphthoquinone 2-hydroxyl group and an axially Pt⁴⁺-coordinated hydroxide ligand in novel 1b-3b has been proposed to favor the Pt⁴⁺/Pt²⁺ reduction, and thus 1b-3b show similar cytotoxicity to their Pt²⁺ counterparts.

Two new 2"-ethyl-furanoflavones and six known furanoflavones were isolated from the stems of Cassia fistula. All the compounds were evaluated for their cytotoxicity against five human tumor cell lines. One of the compounds showed potent cytotoxicity against SHSY5Y and MCF7 cells with IC₅₀ values of 2.7 and 2.6 μmol L^-1, respectively.

The preliminary study suggested that Sb(III) adsorption on paddy soils was stronger than As(III), which could explain the low Sb concentrations found in well waters in Bangladesh. No strong evidence was found for competitive behaviour between Sb(III) and As(III).

The simultaneous detection of hydroquinone and catechol was attained using a simple, easy to prepare, silsesquioxane-modified carbon paste electrode associated to differential pulse voltammetry.

A slurry sampling flame atomic absorption spectrometric (FAAS) method is proposed for the sequential determination of copper and iron in airborne particulate matter (APM) collected on glass fiber filters.