Electrochemical oxidation of dibenzothiophene compounds on BDD electrode in acetonitrile-water medium

The electrochemical oxidation of dibenzothiophene and two derivatives, namely 4-methyldibenzothiophene and 4,6-dimethyldibenzothiophene, was investigated either separately or as a mixture, on a BDD anode in a miscible acetonitrile (87.5% v/v)-water (12.5% v/v, 0.01 M NaNO3) solution. Linear sweep voltammetry, cyclic voltammetry, chronoamperometry and bulk electrolysis under potentiostatic conditions suggested the probable occurrence of two pathways: direct electrochemical oxidation and indirect reaction with hydroxyl radicals and other reactive oxygen species formed at the BDD anode surface during water discharge. The products extracted upon electrolysis at 1.5 and 2.0 V vs. SCE were analyzed by Fourier-transform infrared spectroscopy, gas chromatography-mass spectrometry and ultra-high performance liquid chromatography coupled to electrospray ionization and quadrupole time-of-flight mass spectrometry (UHPLC-ESI-Q-TOF-MS). The main molecules identified were the corresponding sulfoxides or sulfones, depending on the applied anodic potential. Possible oxidation routes for the dibenzothiophene compounds are proposed

Follow-Up Study Confirms the Presence of Gastric Cancer DNA Methylation Hallmarks in High-Risk Precursor Lesions

Intestinal metaplasia confers an increased risk of progression to gastric cancer. However, some intestinal metaplasia patients do not develop cancer. The development of robust molecular biomarkers to stratify patients with advanced gastric precursor lesions at risk of cancer progression will contribute to guiding programs for prevention. Starting from a genome-wide methylation study, we have simplified the detection method regarding candidate-methylation tests to improve their applicability in the clinical environment. We identified CpG methylation at the ZNF793 and RPRM promoters as a common event in intestinal metaplasia and intestinal forms of gastric cancer. Furthermore, we also showed that Helicobacter pylori infection influences DNA methylation in early precursor lesions but not in intestinal metaplasia, suggesting that therapeutic strategies to prevent epigenome reprogramming toward a cancer signature need to be adopted early in the precursor cascade. To adopt prevention strategies in gastric cancer, it is imperative to develop robust biomarkers with acceptable costs and feasibility in clinical practice to stratified populations according to risk scores. With this aim, we applied an unbiased genome-wide CpG methylation approach to a discovery cohort composed of gastric cancer (n = 24), and non-malignant precursor lesions (n = 64). Then, candidate-methylation approaches were performed in a validation cohort of precursor lesions obtained from an observational longitudinal study (n = 264), with a 12-year follow-up to identify repression or progression cases. H. pylori stratification and histology were considered to determine their influence on the methylation dynamics. As a result, we ascertained that intestinal metaplasia partially recapitulates patterns of aberrant methylation of intestinal type of gastric cancer, independently of the H. pylori status. Two epigenetically regulated genes in cancer, RPRM and ZNF793, consistently showed increased methylation in intestinal metaplasia with respect to earlier precursor lesions. In summary, our result supports the need to investigate the practical utilities of the quantification of DNA methylation in candidate genes as a marker for disease progression. In addition, the H. pylori-dependent methylation in intestinal metaplasia suggests that pharmacological treatments aimed at H. pylori eradication in the late stages of precursor lesions do not prevent epigenome reprogramming toward a cancer signature

Effect of Cooking Processes on the Contents of Two Bioactive Carotenoids in Solanum lycopersicum Tomatoes and Physalis ixocarpa and Physalis philadelphica Tomatillos

Calculation of the HPLC chromatographic retention times of different carotenoids supported our improved chromatographic separation of β-carotene and lutein in four tomatoes and two tomatillo varieties in fresh form and after three different cooking procedures: pot boiling, cooking in a pressure cooker and microwaving. A good separation was achieved experimentally using an Ultrasphere ODS column and gradient elution with an acetonitrile-tetrahydrofuran-water mobile phase. It was shown that diverse tomato species contained different amounts of β-carotene (6-400 μg/100 mg) and lutein (2-30 μg/100 mg). The concentration in fresh samples was higher than in cooked tomatoes. The β–carotene content in fresh tomatillo varied between 2 and 20 μg/100 mg. Microwaving caused partial destruction of the β-carotene and lutein in tomatillos

Using Akaike Information Criterion to Select the Optimal Isotherm Equation for Adsorption from Solution

In this study, we measured the adsorption of Basic Blue 41 (BB41) dye on a maize cob adsorbent and on two model adsorbents (cellulose triacetate and cellulose acetate propionate). The experimental adsorption data were evaluated with the isotherm equations of Langmuir, Freundlich, Langmuir–Freundlich and Dubinin–Radushkevich, and constants were obtained exclusively by non-linear regression. In order to select the optimal isotherm equation, Akaike information criterion was used. The celluloses obeyed the Langmuir isotherm in the temperature range tested, whereas the corncob followed the Freundlich equation. This comparative study shows that limited amounts of the cationic dye were adsorbed on the model celluloses than on the cob. BB41 was neither adsorbed horizontally nor vertically onto the cob, whereas it competed with water molecules and despite saturation, did not exhaustively occupy the surface of the celluloses. The Gibbs free energy of adsorption was evaluated using the equilibrium constants obtained by several procedures and the results were found to be inconsistent

Conotrachelus dimidiatus Champion, 1904 (Coleoptera: Curculionidae: Molytinae): morphological re-description of the immature stages, keys, tribal comparisons and biology

Torres, Betzabeth Cecilia Pérez, Skuhrovec, Jiří, Marín-Cevada, Vianey, Elizalde-González, María P. (2018): Conotrachelus dimidiatus Champion, 1904 (Coleoptera: Curculionidae: Molytinae): morphological re-description of the immature stages, keys, tribal comparisons and biology. Zootaxa 4433 (1): 127-140, DOI: https://doi.org/10.11646/zootaxa.4433.1.

TiO2 Immobilized on Manihot Carbon: Optimal Preparation and Evaluation of Its Activity in the Decomposition of Indigo Carmine

Applications of carbon-TiO2 materials have attracted attention in nanotechnology due to their synergic effects. We report the immobilization of TiO2 on carbon prepared from residues of the plant Manihot, commercial TiO2 and glycerol. The objective was to obtain a moderate loading of the anatase phase by preserving the carbonaceous external surface and micropores of the composite. Two preparation methods were compared, including mixing dry precursors and immobilization using a glycerol slurry. The evaluation of the micropore blocking was performed using nitrogen adsorption isotherms. The results indicated that it was possible to use Manihot residues and glycerol to prepare an anatase-containing material with a basic surface and a significant SBET value. The activities of the prepared materials were tested in a decomposition assay of indigo carmine. The TiO2/carbon eliminated nearly 100% of the dye under UV irradiation using the optimal conditions found by a Taguchi L4 orthogonal array considering the specific surface, temperature and initial concentration. The reaction was monitored by UV-Vis spectrophotometry and LC-ESI-(Qq)-TOF-MS, enabling the identification of some intermediates. No isatin-5-sulfonic acid was detected after a 60 min photocatalytic reaction, and three sulfonated aromatic amines, including 4-amino-3-hydroxybenzenesulfonic acid, 2-(2-amino-5-sulfophenyl)-2-oxoacetic acid and 2-amino-5-sulfobenzoic acid, were present in the reaction mixture

Blue Titania: The Outcome of Defects, Crystalline-Disordered Core-Shell Structure, and Hydrophilicity Change

In this research, changes in several characteristics of partially reduced titania were studied. The reduction process used made it possible to gradually observe changes in the material depending on the amount of reducing agent used. We used NaBH4 to impregnate commercial TiO2 with isopropyl alcohol. Impregnated TiO2 nanoparticles were dried and thermally treated in a nitrogen flow to obtain blue titania samples. Thorough spectroscopic characterization showed that oxygen atoms from hydroxyl groups, as well as from the surface, and the lattice of TiO2 was consumed. This caused changes in the surface and even in the bulk of TiO2 when the amount of reducing agent used was increased. Structural, optical, superficial, and textural characteristics were studied using XRD, Raman, DRS UV-Vis-NIR, Mid-DRIFT, XPS, and nitrogen adsorption/desorption isotherms. A photocatalytic test of the degradation of methylene blue dye was performed. Among different effects on the mentioned characteristics, we found evidence of changes in the surface properties of the blue titania samples and their probable effect on the photocatalytic properties. The reduction process implied a preponderant decrease in the surface hydrophilicity of the reduced samples, an effect shown for the first time in this type of material