Evaluation of Anti-Candida albicans Activity and Release of Ketoconazole in PMMA-G-PEG 4000 Films

Modified release systems depend on the selection of an appropriate agent capable of controlling the release of the drug, sustaining the therapeutic action over time, and/or releasing the drug at the level of a particular tissue or target organ. Polyethylene glycol 4000 (PEG 4000) is commonly employed in drug release formulations while polymethyl methacrylate (PMMA) is non-toxic and has a good solubility in organic solvents. This study aimed at the incorporation of ketoconazole in PMMA-g-PEG 4000 and its derivatives, thus evaluating its release profile and anti-Candida albicans and cytotoxic activities. Ketoconazole was characterized and incorporated into the copolymers. The ketoconazole incorporated in the copolymer and its derivatives showed an immediate release profile. All copolymers with ketoconazole showed activity against Candida albicans and were non-toxic to human cells in the entire concentration tested.     

Synthesis,structure and properties of the mixed-ligand tungsten(II) complex [WBr2(CO)3(tmpymt)] (tmpymt = 1,4,6-trimethylpyrimidine-2-thione)

The reaction of [{WBr(CO)₄}₂(μ-Br)₂]₂ 1 with 1,4,6-trimethylpyrimidine-2-thione (tmpymt) affords the air-sensitive complex [WBr₂(CO)₃(tmpymt)] 2. The X-ray structure of 2·C₃H₆O reveals that the geometry surrounding the tungsten(II) atom is best described as a distorted capped trigonal prism with a bromine atom Br(1) in the unique capping position. The other bromine atom Br(2), the (N,S)-chelate and one carbonyl C(41) occupy the capped quadrilateral face. The complex has been additionally characterized by IR and NMR spectroscopy. The optimized molecular structure (RHF/LanL2DZ) supports the experimental data.     

Development of a fast MECK method for determination of 5-HMF in honey samples

In this study, 5-hydroxymethylfurfural (5-HMF) determination was carried out by a micellar electrokinetic capillary chromatography (MEKC) methodology, using caffeine as the internal standard (IS). The optimisation of the electrolyte composition was approached using a 3² full factorial design with a central point to study the MEKC electrolyte components. Inspection of the response surface indicated that the optimal electrolyte composition was 5 mmol L⁻¹ sodium tetraborate (STB, pH 9.3) containing 120 mmol L⁻¹ sodium dodecyl sulphate (SDS). Under optimal CE conditions, separation of the investigated substance was achieved in less than 0.7 min. Quality parameters, such as linearity (R² > 0.99), precision (RSD < 5.41%), detection and quantification limits (3.37 and 11.24 mg kg⁻¹ for honey samples) and recovery (96.37–99.56%). The proposed methodology was successfully applied to the analysis of 5-HMF in honey samples. The analytical performance of this method makes it suitable for implementation in food laboratories for the routine determination of 5-HMF in honey samples.     

Covalent Attachment of FeFe Hydrogenases to Carbon Electrodes for Direct Electron Transfer

Direct electron transfer between enzymes and electrodes is now commonly achieved, but obtaining protein films that are very stable may be challenging. This is particularly crucial in the case of hydrogenases, the enzymes that catalyze the biological conversion between dihydrogen and protons, because the instability of the hydrogenase films may prevent the use of these enzymes as electrocatalysts of H(2) oxidation and production in biofuel cells and photoelectrochemical cells. Here we show that two different FeFe hydrogenases (from Chamydomonas reinhardtii and Clostridium acetobutylicum) can be covalently attached to functionalized pyrolytic graphite electrodes using peptidic coupling. In both cases, a surface patch of lysine residues makes it possible to favor an orientation that is efficient for fast, direct electron transfer. High hydrogen-oxidation current densities are maintained for up to one week, the only limitation being the intrinsic stability of the enzyme. We also show that covalent attachment has no effect on the catalytic properties of the enzyme, which means that this strategy can also used be for electrochemical studies of the catalytic mechanism.     

Consumption of Fish in Chronic Kidney Disease – A Matter of Depth

Fish is an excellent source of ω-3 polyunsaturated fatty acids (PUFAs), amino acids, collagen, vitamins, and iodine and its intake is associated with health benefits, mainly reduces risk of cardiovascular mortality. However, recent studies have shown that fish is also an important source of trimethylamine N-oxide (TMAO), a uremic toxin produced by the gut microbiota that promotes an increased risk of cardiovascular diseases. In patients with chronic kidney disease (CKD), TMAO levels are markedly increased due to gut dysbiosis and reduced kidney function. No study has yet evaluated the effects of a fish-rich diet on TMAO plasma levels and cardiovascular outcomes. This review discusses the pros and cons of a fish-rich diet in patients with CKD – a matter of depth.     

Thermoplastic starch/whey protein isolate/rosemary essential oil nanocomposites obtained by extrusion process: Antioxidant polymers

Active substances are added to polymers to act as a barrier to external elements, protecting the product. This article evaluated the effect of the addition of sodium montmorillonite (MMT) nanoparticles and the antioxidant activity of rosemary essential oil (EO) in thermoplastic starch/whey protein isolate (TPS/WPI) nanocomposites obtained by extrusion. X-ray diffractograms showed dispersion/exfoliation of the MMT in the TPS/WPI matrix. The nanocomposites presented rough surface with the presence of porosity as shown by scanning electron microscopy images. Thermogravimetric analysis revealed that the combination between MMT and rosemary EO increased thermal stability of nanocomposites. The addition of rosemary EO became the films less rigid, weaker and had an antioxidant effect as shown by mechanical properties and 2,2-diphenyl-1-picrylhydrazyl assay. The optical properties showed in opaque greenish yellow nanocomposites. Therefore, the addition of rosemary EO in nanocomposites showed an alternative for use as antioxidant polymers in packaging material. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47619.     

Carbon markets and low-carbon investment in emerging economies: A synthesis of parallel workshops in Brazil and India

While policy experiments targeted at energy and innovation transitions have not been deployed consistently across all countries, market mechanisms such as carbon pricing have been tested over the past decade in disparate development contexts, and therefore provide some opportunities for analysis. This brief communication reports on two parallel workshops recently held in Sao Paulo, Brazil and New Delhi, India to address questions of how well these carbon pricing policies have worked in affecting corporate decisions to invest in low-carbon technology. Convening practitioners and scholars from multiple countries, the workshops elicited participants' perspectives on business investment decisions under international carbon markets in emerging economies across multiple energy-intensive sectors. We review the resulting perspectives on low-carbon policies and present guidance on a research agenda that could clarify how international and national policies could help encourage both energy transitions and energy innovations in emerging economies.     

Phenolic compounds and antioxidant activity of seed and skin extracts of red grape (Vitis vinifera and Vitis labrusca) pomace from Brazilian winemaking

The phenolic compounds content and antioxidant activity of seed and skin of pomace from the vinification of grape varieties widely produced in Brazil were investigated with a view to their exploitation as a potential source of natural antioxidants. There was a greater concentration of phenolic compounds in the seeds (2128 to 16,518 mg of catechin equivalents (CE)/100 g) than in the skins (660 to 1839 mg CE/100 g). The highest antioxidant activity values determined as DPPH radical-scavenging ability and ferric reducing-antioxidant power (FRAP) were found for the seeds of the Pinot Noir variety (16,925 ??mol Trolox equivalents (TE)/100 g and 21,492 ??mol Fe²⁺/100 g, respectively) and in the skin extracts of the Isabel variety (3640 ??mol TE/100 g and 4362 ??mol Fe²⁺/100 g, respectively). The skin of Cabernet Sauvignon and Primitivo varieties had the highest contents of anthocyanins (935 and 832 mg/100 g, respectively). The grape seed extracts were rich in oligomeric and polymeric flavanols. The data suggested that grape seed and skin extracts may be exploited as antioxidant agents.