Resumo em Inglês:

Ozone (O3) is a secondary pollutant, and modeling studies used to assess its behavior play a role in facilitating regulatory and decision-making processes in public policies. Thus, the Community Multiscale Air Quality (CMAQ), a chemical transport model, was specifically designed to simulate and forecast O3 concentrations. This critical review includes publications between 2016 and 2023 showing the most used configurations. The research was carried out in the Scopus and Web of Science databases, and the articles were filtered using determined criteria. With this, it was observed that the most used model arrangements are Weather Research and Forecasting as a meteorological model, carbon bond 2005 as the chemical mechanism, 36 × 36 km with 35 vertical layers as grid resolution, CMAQ standard profiles as a boundary condition, Multi-resolution Emission Inventory for China, due to the high number of publications by Chinese researchers, and Model of Emissions of Gases and Aerosols from Nature as inventory and processor of biogenic emissions, respectively. It is concluded that this arrangement of configurations is the most widespread in the literature but shows that nowadays the publications predominantly lie over China and with greater prominence of this country in studies of influence on ozone simulation.

Resumo em Inglês:

In this short review, we address carbamates, a class of chemical compounds derived from carbamic acid, which have garnered attention as both valuable assets and potential hazards across diverse applications. Their stable structure, characterized by the R–O–CONH–R functional group, allows for various substituents, enabling their use in medicine, agriculture, and even as chemical warfare agents. In medicine, carbamates play a significant role as components of numerous medications approved by Food and Drug Administration. The stability and permeability properties of carbamates have led to the enhancement of various pharmacological compounds, aiding drug development. In agriculture, carbamates have been used as pesticides to manage pests and increase crop productivity. Despite their effectiveness, overuse and inadequate regulation have raised concerns about environmental contamination and health risks. In this review, we also seize the opportunity to present information to the readers about the framework of international agreements on toxic compounds, highlighting their potential misuse as chemical warfare agents and how they have been a reason of concern, with their high toxicity across various exposure pathways. The inclusion of certain carbamates in the Chemical Weapons Convention underscores their lethal nature. However, they lack comprehensive research, raising questions about their complete effects and potential countermeasures.

Resumo em Inglês:

This study aimed to establish the longitudinal gradient and historical trends of arsenic and metals in a tropical reservoir. Water and sediment samples were collected along the Rio Bonito reservoir (Espírito Santo, Brazil), and a sediment core was obtained from the lacustrine zone. Plasma spectrometric techniques were employed to determine concentrations of As, Cd, Co, Cu, Fe, Mn, Ni, and Pb in water and sediment samples, and the sediment samples were dated using high-resolution gamma spectrometry. Higher concentrations of elements were observed in surface water samples from the riverine zone and bottom water samples from the transition zone. Concerning surface sediment samples, elevated concentrations were noted in the transition and lacustrine zones, where deposition is more intense. The sediment core was dated to 1940, before the reservoir dam construction, utilizing 210Pb dating. Certain elements exhibited progressively increasing concentrations over time. Enrichment factor, pollution load, and ecological risk indexes indicated the need for continuous monitoring of this reservoir.

Resumo em Inglês:

Nanocomposites of magnetite anchored on reduced graphene oxide with different magnetite:reduced graphene oxide mass ratios were synthesized and evaluated in indigo carmine photo Fenton discoloration. All nanocomposites are magnetic and showed comparable amounts of magnetite and hematite with a higher level of hematite for low iron contents. The highest value of 63.6 emu g−1 was obtained for the nanocomposite with the highest magnetite content. The nanocomposites presented high dispersion of iron oxide particles, at about 12 nm on reduced graphene oxide surface sheets. The samples also showed bandgap energies below that found for bulk magnetite, showing an important effect of reduced graphene oxide. The nanocomposite with an iron nitrate precursors mass ratio of 17:1 showed the best performance (99.7% of indigo carmine discoloration (2.1 × 10−5 mol L−1) at 30 min of reaction, hydrogen peroxide (2.3 × 10−1 mol L−1), and a catalyst dosage of 0.67 g L−1). Reusability tests were performed, and this nanocomposite was shown to be active for at least three recycles. X-ray photoelectron spectrum of Fe2p3/2 showed that the FeIII/FeII ratio was maintained even after three recycles (4 runs), meaning that reduced graphene oxide is responsible for stabilizing magnetite particles, thus maintaining its photocatalytic activity.

Resumo em Inglês:

Natural waters from the Paraná River hydrographic basin in the Brazil-Paraguay cross-border region were analyzed by liquid chromatography coupled to a fluorescence detector (LC-FLD) after extraction of the analytes in anion exchange resin IRA-900. The method allowed good recovery (91 to 113%) of the studied species (glyphosate, (aminomethyl)phosphonic acid (AMPA) and glufosinate) precision compatible with the requirements of the National Metrology Institute (relative standard deviation < 18%) and limit of quantification (LOQ) values between 0.2 and 0.8 μg L−1. In most of the samples collected between January and September 2022, it was impossible to detect the presence of herbicides, even in regions of intense agricultural activity, probably due to the high adsorption capacity of the soils of the region and due to the higher LOQ of the method. Under these conditions, the main transport route is estimated to be associated with surface runoff, which is only favored by heavy rainfall events.

Resumo em Inglês:

A new composite material with magnetic and pH-responsive properties, composed of chitosan/poly(2-diisopropylamino)ethyl methacrylate (Fe3O4/SiO2/CS/PDPA) was developed with the purpose of removing avermectins in aqueous media. The material was characterized by different techniques to evaluate its characteristics. The adsorption process was investigated through the optimization of some parameters, with the most favorable results at pH 8.0, using 20 mg of adsorbent and stirring for 5 min. Under such conditions, the material showed adsorption efficiency of around 80.5, 69.9, and 74.8% for eprinomectin, doramectin and ivermectin, respectively. The adsorption mechanism was investigated using the pseudo-second order kinetic model and the Langmuir-Freundlich dual site isotherm model. Thermodynamic analysis indicated that the adsorption process is exothermic and spontaneous. The material also showed good regenerative capacity, allowing several reuse cycles. The results obtained suggest that the synthesized material has potential application as an adsorbent in the removal of avermectins from aqueous samples.

Resumo em Inglês:

Food fraud, such as the adulteration of extra virgin olive oil (EVOO), is found to cause substantial negative impacts on both the economy and the health of consumers. This work was aimed at evaluating 19 EVOO samples commercialized in Foz do Iguaçu, a frontier city located around the triple border of Brazil, Argentina, and Paraguay. To detect the presence of adulteration in EVOO samples, the present study employed gas chromatography coupled to flame ionization detector (GC-FID) and headspace solid phase microextraction with gas chromatography coupled to mass spectrometry (HS-SPME-GC-MS) in order to evaluate fatty acids composition and volatile organic compounds (VOCs), respectively. The quantitative results obtained from the analysis of fatty acids composition showed that 32% of the EVOO samples were adulterated, presumably with soy oil, due to the high levels of linoleic, linolenic, and myristic acids present in them. Principal component analysis (PCA) conducted using the complete chromatographic aroma profiles obtained from the VOCs helped distinguish authentic EVOO samples from adulterated ones and the country of origin of the samples. The following aromatic compounds were first described, as possible adulterant markers: 3,3-dimethylheptanoic acid, propyl pentanoate, methyl cyclohexanecarboxylate, ethyl cyclohexanecarboxylate, 2-phenylethyl acetate, 6,10,14-trimethylpentadecan-2-one, and 1,2-dimethoxy-4-methylbenzene.

Resumo em Inglês:

The ionizing radiation used in radiotherapy can break down deoxyribonucleic acid bonds, generate reactive oxygen and nitrogen species, alter intracellular proteins, and induce changes in the lipidome. This study delves into examining lipid classes and their spatial distribution in the brains of Wistar rats exposed to ionizing radiation. Healthy male isogenic Wistar rats (n = 15) were divided into a control group (CG, n = 3) and an irradiated group (IRG, n = 12). The individuals of the IRG group were subjected to total body irradiation (TBI) using a Co-60 source and a radiation dose of 5 Gy. The IRG group was subdivided into four subgroups corresponding to 168, 96, 48, and 24 h before sacrifice. The brains were sliced into the sagittal direction, and the slices were analyzed using the desorption electrospray ionization mass spectrometry imaging (DESI-MSI) approach. The mass spectrometry results and information from the Metabolite and Chemical Entity Database (METLINTM) and Lipid Metabolites and Pathways Strategy (LIPID MAPS) databases enabled the identification of lipids belonging to distinct classes. The DESI-MS images revealed distinctive spatial distributions of these lipids and the modulatory response induced by the radiation over time.

Resumo em Inglês:

In this paper, we report the characterization of Brazilian red propolis from two origins. The commercial value of this product is due to its composition and bioactivity, which depend on geographical factors. Total and individual phenolic, antioxidant, and medium infrared spectroscopic (MIR) characterization of 72 red propolis samples from two origins (Bahia (BA) and Rio Grande do Norte (RN), Brazil) were performed. Samples from RN showed higher concentrations of biomarkers. The BA samples showed higher antioxidant capacity despite having lower concentrations of the red propolis biomarker molecules when compared to the RN samples. The MIRS showed differences regarding the origin. The principal component analysis confirmed the differences, generating well-defined groups. Linear discriminant analysis or discriminant analysis and and partial least squares discriminant analysis showed excellent model performance. The models with MIRS data from raw propolis have a high correct classification rate and require no sample preparation. These findings can affect red propolis production, boosting sustainable extractivism, and changing the reality of small communities.

Resumo em Inglês:

The microwave-assisted interesterification of babassu oil with methyl, ethyl and butyl acetates was carried out via acid catalysis, using sulfuric, phosphoric, methanesulfonic and acetic acids for the production of biodiesel with triacetin as an additive. Dielectric measurements in the range of 0.3 to 13 GHz of pure reactants and reactions media lead to a clear understanding of the interaction between the medium and microwave irradiation, allowing achieving optimal conditions in terms of microwave power, kind and catalyst concentration, reactant molar ratios, and temperatures. Using ethyl acetate, reactions were carried out at various oil to acetate molar ratio (1:12 to 1:72) using sulfuric acid (0.5% m/mT) as a catalyst. For 1:60 molar ratio, the experiments were carried out with 0.5 to 2% m/mT sulfuric acid. The kind of catalyst and the applied microwave power to mass ratio were investigated using H3PO4, CH3COOH and CH3SO3H. The best catalytic activities were achieved with H2SO4 and CH3SO3H. It was found that under microwave or conventional heating the reactivity follows the ethyl→methyl→butyl trend. The best results were achieved using ethyl acetate with H2SO4 which yields 91.1% biodiesel and 18.3% triacetin in 120 min under microwave heating while using CH3SO3H yields 80.1% biodiesel and 11.2% triacetin.

Resumo em Inglês:

This study aimed to develop a healthy and antioxidant-rich mixed juice. The effect of the vegetables combination on the juice characteristics was evaluated and, to optimize the proportion components of the mixture, chemometric modeling was used. The maximum antioxidant activity was considered as a variable response. The mixed juice was evaluated for technological parameters (content of soluble solids, titratable acidity, density, viscosity, sedimentation, and color parameters). The phenolic compounds present in the vegetables were identified by ultra-high performance liquid chromatography-mass spectometry (UHPLC-MS) technique. The special cubic model was considered significant (p < 0.05), with low dispersion and homogeneous antioxidant activity data (coefficient of variation (C.V.) = 3.73%) and the most appropriate for statistical data analysis (R2 = 0.9937). The optimal formulation consisted of a blend (m/m) with orange (73.37%), apple (20.45%), kale (5.58%), and ginger (0.59%) with greater desirability, 12534.2 μmol mL-1 of validated antioxidant activity and adequate physicochemical characteristics. The addition of orange juice resulted in a product with better functionality, due to the increased antioxidant capacity. This innovative study resulted in a functional formulation that involves the combination of low-cost vegetables with the maximum possible antioxidant action, capable of helping to protect against damage caused by free radicals.

Resumo em Inglês:

Hydrogel films based on gelatin, glutaraldehyde and glycerol are widely reported in many studies with applications focused on food packaging, microencapsulation and release of active drugs. Thus, this study used this composition to produce hydrogel films and brought as a novelty the incorporation of tannic acid (TA) as anti-aging active, due to its great antioxidant capacity. The presence of TA in the hydrogel films was verified by the C–O stretch absorption band at 1020 cm-1, as well as by its thermal degradation between 200 and 300 ºC. Furthermore, the presence of this active compound, which influenced the physical, morphological and mechanical properties of the film, was also confirmed by qualitative release tests. Additionally, the mechanical properties of the HT2 hydrogel film showed acceptable values of elongation at break (28.9 ± 3.1%) and Young modulus (6.4 ± 1.1 MPa), suggesting that this film has the potential to be applied in skin care routines.

Resumo em Inglês:

Thiophosphonates, a class of the organophosphate compounds, are of pharmaceutical and agricultural significance. Albeit their broad scope for peaceful uses, they may also be precursors and markers to toxic chemicals, such as the nerve agent VX and other V-series agents, leading to their inclusion into the Annex on Chemicals of the Chemical Weapons Convention (CWC). Considering that they are related to chemical warfare agents and the position of our laboratory as an Organization for the Prohibition of Chemical Weapons (OPCW) Designated Laboratory for analysis of authentic environmental samples, this study aims to contribute to the understanding of the synthesis of thiophosphonates through O,O ’-diethyl methylphosphonate conversion to O,O ’-diethyl methylphosphonothioate using Lawesson’s reagent, exploring different conditions previously reported by the literature, in order to further build a compound library for CWC verification purposes. Synthesis of the compounds has been carried out in sealed, pressure tubes, adding novelty to the present study. Reactions were followed by gas chromatography and 31P nuclear magnetic resonance, and principal component analysis was employed to understand the intricate factors influencing thiophosphonate synthesis yield as duration, temperature and solvent. The research aims to reinforce or challenge existing scientific knowledge, providing insights into parameters related to phosphonate thionation using Lawesson’s reagent, contributing to a deeper understanding of this chemical reaction.