Resumo em Inglês:

The ubiquity of microplastics ecosystems has gained global attention. In this context, Latin America, which is responsible for 8% of the world’s consumption of plastic material and has a small recycling rate (4.5%), does not have enough data on microplastics contamination in its environmental matrices. This systematic review analyzed 196 studies from 16 territorials in Latin America and provided information about the current state of knowledge regarding the abundance, distribution, and associated impact of microplastics in different matrices. This review also describes the analytical procedures of sampling, extraction, identification, and characterization methodologies adopted by the literature review. The analysis shows that most of the studies that investigate microplastics abundance were carried out in the marine environment (59%), and there is an insufficient investigation on microplastics abundance in freshwater bodies (16%). Among all the studies, the highest microplastics concentration was observed in regions with high population density and/or in locations without proper sanitation and solid waste management. Additionally, the difference among microplastics abundance in the studies might be associated with the different analytical procedures employed to investigate microplastics. Lastly, knowledge gaps are identified, and recommendations are proposed to guide future studies on microplastics contamination.

Resumo em Inglês:

This work reports the characterization of a vegetable oil extracted from pequi seeds, an agroindustrial residue, and its biodiesel production using ethanol and heterogeneous catalysis. The pequi seeds showed 40.73 wt.% of extractive content, which represents a large amount of the biomass composition. The crude oil extracted from the pequi seeds with ethanol as solvent presented a high content of free fatty acids (FFAs), mainly oleic (54.14%) and palmitic (36.71%) acids, resulting in an acidity value of 13.8 ± 0.1 mg KOH g-1. The esterification/transesterification process was performed using two ion exchange resins as heterogeneous catalysts, a commercial protonic form (assigned as PR) and a zirconium-exchanged (assigned as PRZr). Conversions of 87.1 and 91.4% were achieved for PR and PRZr as catalysts, respectively, at optimal conditions (1:6 oil-to-alcohol molar ratio, 25 wt.% of catalyst, 100 ºC and 1 h). These results indicated that heterogeneous acid catalysts can be successfully applied in biodiesel production from fatty acid-rich oils, such as the one extracted from pequi seeds. Also, a simultaneous process involving both oil extraction and biodiesel production was tested using PRZr as catalyst (25 wt.% of catalyst and 100 ºC), but due to the greater amount of ethanol necessary for the oil extraction (1:16 oil to alcohol mass ratio) the conversion reached only 51.5% after 5 h. For that reason, this work proposes a two stage system for biodiesel production that integrates oil extraction (stage one) and the esterification/transesterification reaction (stage two) to achieve a greener process, waste-to-bioenergy.

Resumo em Inglês:

In this work we developed a promising analytical method combining Fourier transform near-infrared (FT-NIR) spectroscopic technique and first-order multivariate calibration using partial least-squares (PLS) model to simultaneously quantify the main greenhouse gases (GHG’s): methane (CH4), carbon dioxide (CO2), nitrous oxide (N2O) and water vapor (H2O). The models were built using 70 mixtures with different concentration of these gases, 0.25-32.0 ppm to CH4 and N2O, and 50-1100 ppm to CO2 and different values of relative humidity (52-85%, 20 ºC) in synthetic air. After preparing each of the mixtures, they were analyzed by using FT-NIR and a reference analytical technique based on gas chromatography with mass spectrometric detection (GC-MS). The FT-NIR spectrometer was coupled with a long optical path cell, with 105.6 meters of optical path. In sequence, the spectra of all mixtures and its concentration values for each gas were used to build the multivariate calibration models, using PLS regressions. For this, the mixtures were grouped with Kennard Stone algorithm, 50 samples to calibration set and 20 samples to prediction set. The values of RMSEP (root mean square error of prediction) obtained for each model are 0.66, 28.7 and 0.66 ppm, respectively, for CH4, CO2, and N2O. The limits of quantification (LOQ) for each PLS models are 0.26, 3.6, and 0.99 ppm, respectively, for CH4, CO2, and N2O. The results show the potentiality of application of this system to monitoring emission sources in which the concentration of these gases are relatively high, as urban centers, industrial areas, and landfills.

Resumo em Inglês:

Considering the promising antitumor effects of compounds with dual anti-inflammatory and antiproliferative activities, thus benzophenones analogs (2-7) were evaluated on in vivo anti-inflammatory assay and molecular docking analysis. Those with the best molecular docking results were in vitro evaluated on cyclooxygenase (COX) enzymes and tested regarding antiproliferative activity. All derivatives displayed in vivo anti-inflammatory activity. Among them, the substances 2’-hydroxy-4’-benzoylphenyl-β-D-glucopyranoside (4), 4-hydroxy-4’-methoxybenzophenone (5) and 4’-(4’’-methoxybenzoyl)phenyl-β-D-glucopyranoside (7) showed the best values of Glide Score in COX-2 docking evaluation and 4 and 5 selectively inhibited COX-2 and COX-1 in vitro enzymatic assay, respectively. Thus, 4 and 5 were tested against breast cancer (MCF-7, MDA MB-231, Hs578T) and non-small-cell-lung cancer (A549) cell lines. The estrogen-positive MCF-7 cell line was more responsive compared to other tested cell lines. They induced cell cycle arrest at G1/S transition in MCF-7 cell line once there was an increase in G0/G1 population with concomitant reduction of S population. The antiproliferative activity of these substances on MCF-7 was associated with their ability to inhibit cyclin E expression, a critical regulator of G1/S transition. Taken together, the data indicate that 4 and 5 have dual anti-inflammatory and antiproliferative activities and support further studies to evaluate their antitumor potential.

Resumo em Inglês:

Synthesis of carbon dots (CDs) from natural resources not only enables green synthesis and production of environmentally friendly materials, but also provides a cost-effective probe as a fluorescence nanosensor. The proposed sensor introduces a unique one-pot hydrothermal CDs synthesis from alfalfa leaves, which is promising for sensing hydrochlorothiazide (HCTZ) via inner filter effect (IFE) and resonance Rayleigh scattering (RRS). The as-prepared CDs had wide emission spectra, excitation-dependent emission, high solubility, high stability, and visible fluorescence light with a quantum yield of up to 11%. The absorption of HCTZ overlapped with the excitation spectra of CDs. Therefore, CDs represented excellent quenching due to IFE when HCTZ was gradually added. Furthermore, this fluorescent sensor was successfully used to quantify HCTZ in the linear ranges (0.17-2.50 μg mL-1) with the limit of detection of 0.11 μg mL-1. The sensing system was simple as no surface functionalization was required for CDs, leading to less laborious steps and more cost-effective synthesis. The reaction time was short, i.e., less than 2 min, indicating a simple approach for rapid analysis of HCTZ. By optimizing conditions, successful measurements were carried out on pharmaceutical tablets.

Resumo em Inglês:

The Barreirinha Formation-Upper Devonian, is the main petroleum source rock of the Amazon Basin, deposited during the great Devonian Transgression, contributing to significant accumulations of organic matter (OM) in anoxic conditions, which allowed its preservation. The present work had the objective of characterizing the molecular composition of biomarkers in outcrops samples of the Barreirinha Formation, aiming to evaluate the paleoenvironment, thermal evolution, and the preservation of OM total organic carbon (TOC) and Rock-Eval pyrolysis indicate considerable amounts of immature OM deposited in a low oxygenation environment. Gas chromatography-mass spectrometry (GC-MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS) data corroborate that the OM was deposited in a suboxic to the oxic environment and low salinity (absence or low relative abundance of β-carotane and gammacerane). 24-N-Propyl-cholestane was detected and identified by synthetic pattern co-injection. High concentrations of tetracyclic polyprenoids (TPPs) in ascending order from base to top, high hopane/sterane ratios, to suggest that the samples had a high molecular weight n-alkanes, C29 steranes, low thermal evolution, and anoxic depositional paleoenvironment.

Resumo em Inglês:

The influence of the film formed during the salting of champignon mushrooms with brine containing NaCl and KCl was modeled using the finite elements method (FEM). It was verified that the film formed on the mushroom surface had a greater influence in the static salting since the diffusion of the ions was 7.5-fold smaller in this system than in the stirred salting. The application of self-organizing maps showed that the ions diffusion along the surface of the solid presented a heterogeneous occurrence and depended on the region for both static and stirred salting. A direct relation was observed among the mushroom surface morphology, the salts diffusion behavior, and the film formation. In addition, the film was not completely extinguished in the stirred system, although it has a minimal influence as the film formation is also dependent on the biosolid surface.

Resumo em Inglês:

This study involved an animal experiment in which testosterone propionate was intramuscularly injected into four steers, and the ensuing urine samples were analyzed using high-performance liquid chromatography-tandem mass spectrometry. The enzymatic hydrolysis conditions were analyzed using analysis of variance (ANOVA) and response surface methodology employing a 33 Box-Behnken design. A survey study was performed in which 48 urine samples were collected from eight untreated steers to estimate the endogenous levels of testosterone metabolites, and it was found that 17β-testosterone was not detected in the majority of the samples, whereas 17α-testosterone was present in 43 of the 48. Drug abuse was identified within 11 days of 17β-testosterone administration. The ratio between both isomers was also assessed; however, a cut-off limit based on an untreated population could not be estimated due to the absence of the beta isomer. Therefore, there may be a correlation between the exogenous use of testosterone in castrate animals and high levels of 17β-testosterone, although confirmation through further investigation would be required.

Resumo em Inglês:

A potential eco-friendly method without organic solvents is presented by integrating a chromatographic fingerprint and multivariate control chart based on Q residuals to differentiate grape juices from different farming practices. The sample preparation was only water dilution, and the mobile phase was water acidified with sulfuric acid, which can be readily neutralized before its disposal. The proposed method is shown to be a simple way to distinguish between organic and non-organic grape juices in a non-target way, successfully evaluating an external validation data set, where organic and non-organic samples were correctly assigned. Through the chromatographic profile, it is possible to suggest that one of the species responsible for this distinction may be from the anthocyanins class.

Resumo em Inglês:

Two different gold-silica-based nanomaterials were prepared: (i) silica-supported gold nanoparticles (AuNP/SiO2); and (ii) gold-silica core-shell nanoparticles (AuNP@SiO2). Three strategies for sample treatment (S), consisting in acid treatments, were employed: (S1) HNO3; (S2) HNO3 + HCl; and (S3) HF + HNO3 + HCl, applying microwave oven digestion for S2 and S3. From three calibration curves, slope, intercept, and linear correlation coefficient were obtained. The accuracy of the methods was evaluated by comparing the gold contents in a sample determined by flame atomic absorption spectrometry (FAAS) and by inductively coupled plasma atomic emission spectrometry (ICP-OES). Finally, the amount of gold for all samples was determined by FAAS. UV-Vis spectroscopy and transmission electron microscopy (TEM) were used to compare the material before and after sample treatment. By comparison, the application of S2 and S3 allowed the presence of gold on or in the silica matrix to be determined and the amount quantified.