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Films based on pure native starch have limited applications, are easily breakable, very hygroscopic, and permeable to water vapor. One method for improving these properties is to modify starch by cross-linking. The aim was to evaluate the effect of the addition of sodium trimetaphosphate (STMP), sodium sulfate (SS) and native cassava starch (S) on the properties of modified cassava starch films using a 23 factorial design comparing the concentration of the crosslinkers (5.0, 12.5 and 20% STMP), SS (3.0, 9.0 and 15%) and native cassava starch (S) (5.0, 7.5 and 10%) m/v. All cross-linked cassava starch films had better easiness of handling, continuity, and brightness than the control film. Generally, cross-linking reduced the water solubility and tensile strength and increased thickness, elongation and the films’ yellowish color and opacity. Reagents’ concentration affected most of the dependent variables. The SMTP*SS interaction positively affected water vapor permeability (WVP), while negatively affected solubility. Tensile strength was positively affected by SMTP. As for elongation, the S*SS interaction was positive, while the effect of STMP*SS was negative. Treatment 1, using the lowest concentrations of reagents, presented positive results, such as excellent macro and microscopic appearance. These findings also qualify the crosslinked starch for use in coatings formulations.

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BIOPROSPECTING OF ESSENTIAL OILS WITH POTENTIAL FOR PHARMACEUTICAL FORMULATIONS. Essential oils derived from aromatic plants have garnered significant attention for their therapeutic and medicinal properties. Among these, α-thujone and β-thujone stand out due to their notable biological effects. This study aimed to assess native and exotic aromatic plants as potential sources of these bioactive compounds. Based on the literature, five plant species were selected: Artemisia absinthium (Asteraceae), Hyptis marrubioides (Lamiaceae), Salvia officinalis (Lamiaceae), Tanacetum vulgare (Asteraceae), and Thuja occidentalis (Cupressaceae), resulting in the analysis of 19 samples. The plant leaves were dried, and their essential oils were extracted and evaluated for yield and chemical composition. The oil yields ranged from 0.15 to 1.57%. Gas chromatographymass spectrometry (GC-MS) analysis identified 82 major volatile constituents, with particular emphasis on α-thujone and β-thujone. Among the species studied, H. marrubioides (62.7%) and T. occidentalis (76.4%) exhibited the highest relative concentrations of α-thujone, while A. absinthium was especially rich in β-thujone (63.91%). Overall, α-thujone and β-thujone were detected in four samples from three species, underscoring their potential as valuable sources of these bioactive compounds. Notably, the native species H. marrubioides demonstrated an essential oil composition comparable to that of T. occidentalis in terms of thujone content, further supporting its viability for industrial and pharmacological applications.

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The waters of the carboniferous basin located in the South of the Brazilian State of Santa Catarina, which are comprised of the hydrographic basins of the Urussanga, Tubarão and Araranguá Rivers (HBA), are an important hydrological resource. Due to the importance of the Sangão River, we evaluated the quality of its surface waters through detection of pharmaceutical contaminants and evaluation of physicochemical parameters. Six contaminants were detected in analyzed samples, including caffeine in all samples. Notable parameters included pH (observed range between 3-7.5), dissolved oxygen (1.08-9.52 mg mL-1), total iron (2.05-56.7 mg L-1), conductivity (2.10-1755 µS cm-1), biochemical oxygen demand (2.5-7.5 mg mL-1), phosphorus (0.02-0.29 mg L-1) and thermotolerant coliforms (values > 9.4 × 103 colony-forming unit (CFU) per 100 mL). We determined the water quality index (WQI) of the samples and performed an acute ecotoxicological study using zebrafish embryos. The results of the WQI revealed that although the source (N1) was classified as regular, samples collected upstream (RS2) and downstream (RS3) of the wastewater treatment plant (WWTP) were considered bad. In the ecotoxicological analysis, all embryos tested in groups RS2 and RS3 were not viable 24 h post-fertilization, although those collected at source survived the experiment. Collectively, our results inform the conclusion that the surface water quality of the Sangão River is impacted from its source onwards, and that remedial strategies are warranted.

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This study investigated the use of plant-based surfactants extracted from tangerine peels as nanoparticle stabilizing agents as an environmentally friendly alternative to synthetic surfactants. Three extraction methods were evaluated, with the acid-base method being selected. The plant extract demonstrated emulsifying and surfactant properties, reducing the surface tension of water from 72 to 30 mN m-1 and showing stability under extreme pH and temperature conditions. The extract, which is anionic in nature, was not toxic to aquatic organisms or plant seeds. The surfactant present in the extract was isolated and characterized. The silver nanoparticles stabilized with the biosurfactant were evaluated morphologically and showed stability, rounded shape with sizes between 300-500 nm, with a zeta potential of -86.30 mV and ultraviolet-visible (UV-Vis) microscopy with a maximum peak between 400 and 450 nm, characteristic of silver nanoparticles. These nanoparticles showed antimicrobial activity against Escherichia coli and Staphylococcus aureus. This study suggests the potential of plant biosurfactant as a stabilizer of silver nanoparticles with antimicrobial properties.

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Iron plays an essential role in the metabolic balance of living beings. Iron also acts as an indicator of redox conditions in the aquatic environment, and a nutrient available in the soil for plant cultivation, which can be released during consumption. The iron content in samples of medicinal plant infusions was monitored by colorimetry, through the acquisition of digital images by smartphone, through the formation of the [Fe(H2O)5(SCN)]2+ complex in small sample volumes (500 µL). This work proposes a promising combination of standard addition calibration with multiple linear regression (MLR-SA) combined with exploratory analysis tools (principal component analysis, PCA, and hierarchical cluster analysis, HCA) to characterize an iron bioavailability profile in infusion samples. Calibration models were obtained with up to 97% of variance explained even in conditions of external light interference and matrix effects. The exploratory analysis revealed a ferric profile of commercial infusions distinguishable from infusions of natural origin. The multivariate approach to digital imaging data has proven to be an alternative methodology for affordable and sustainable monitoring of iron in infusion samples.

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Berberine represents a prominent compound with commendable antitumor activity, a novel berberine derivative with substituted o-diaminobenzene moiety linked at the 9-position through oxadiazole and alkyl chain is designed, synthesized by reference to the histone deacetylase (HDAC) inhibitor structure mode through selective demethylation, substitution, hydrazolysis, acylation, cyclization, elimination, condensation reaction. The structures of these synthetic derivatives were characterized and confirmed by 1H NMR (nuclear magnetic resonance), 13C NMR, and MS (mass spectrometry) spectral data and finally evaluated for antitumor activities against MHCC97H, HCC827, HELA, and HEL cell in vitro by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) method. The results demonstrated that target compound 8 exhibited better antiproliferative activity against the MHCC97H cell line, with a half maximal inhibitory concentration (IC50) = 5.4 ± 0.45 μM L−1 superior to berberine, and the activity against MHCC97H was nearly close to the reference drug doxorubicin. Through the dynamics of molecular docking and simulation, further analysis has demonstrated that the target compound 8 can form effective interactions with the HDAC6 target protein, and the results of binding free energy also revealed a strong affinity between the compound 8 and the HDAC6 protein. The results of this study suggest that compound 8 may be a potential inhibitor of HDAC6, which could have promising applications in the treatment of certain cancers.

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Sodium chloride, NaCl, was analyzed using two models based in classical physics with the main objective of verifying whether this ionic crystal is active or not to infrared absorption. The results from the first reduced mass linear diatomic model (RMLDM) which uses the concept of reduced mass, showed that NaCl is inactive in infrared radiation. In contrast, the linear diatomic model (LDM) indicated that from a theoretical point of view there may be a weak or even insignificant absorption in the vibrational bands ν̅ ≅ 1524 and 1421 cm-1 with the amplitudes of these ionic molecular vibrations varying between 5.5 × 10-12 and 9.5 × 10-12 m. Furthermore, the LDM model developed here in this study, combines elementary equations from classical physics with elements from quantum physics enabling to estimate the energy absorption of the NaCl and also the ions sodium and chloride with good accuracy. This model can be applied, in principle, to other diatomic molecules as a good approximation to molecular vibrational.

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Radon, a natural alpha-emitting radioactive gas, predominantly comprises the isotope 222Rn from the 238U series, accounting for 54% of the natural dose in homes. This study developed a radon simulator for enhanced indoor monitoring, using a high-uranium-content source, achieving average radon concentrations of 3,200 ± 324 and 4,654 ± 467 Bq m-3 with passive and active methods, respectively. The simulator facilitated expanded research, in vivo monitoring, and meter certification, offering a cost-effective tool to manage the health impacts of radon and promote radiation safety standards.

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Polymer-based fracturing fluids are widely used in unconventional reservoirs but often fall short in complex conditions. This study synthesizes a novel hydrophobic association water-soluble polymer (PAMNC12) and explores its synergy with viscoelastic surfactants (VESs: oleic acid amide propyl trimethylammonium chloride (OTAC), oleic acid amide propyl sulfobetaine (ODSB), oleic acid amide propyl carboxyl betaine (ODCB)) to optimize fracturing fluid performance. PAMNC12 exhibits critical association concentrations at 1029.2 and 2513.2 mg L-1. Rheological, gel-breaking, and core damage tests reveal that VES-PAMNC12 synergy significantly enhances apparent viscosity, viscoelasticity, drag reduction, heat/shear resistance, and proppant-carrying capacity while reducing residue content and core damage. Optimal dosages are 400 mg L-1 VES and 10,000 mg L-1 KCl. Among the systems, PAMNC12/OTAC shows superior thickening, heat/shear resistance (160 °C), drag reduction (lowest settlement velocity), and minimal residue (30 mg L-1) and core damage (10.1%). PAMNC12/ODSB and PAMNC12/ODCB also demonstrate excellent heat tolerance, sand-carrying, drag reduction, and low formation damage, making them promising for hydraulic fracturing in unconventional reservoirs. This study provides a foundation for developing high-performance fracturing fluids.

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Blends of poly(methyl methacrylate)/polystyrene (PMMA/PS) in compositions 95/05 and 90/10, with and without the surfactant octadecylamine (ODA), were studied. Analysis of the results obtained by a viscosimetric method using the classical models, Fourier Transform Infrared Spectroscopy (FTIR), and refractive index showed that the blends are immiscible. However, viscosimetric analysis of miscibility using the cluster model showed that polymeric aggregates are formed in blends with ODA. Such aggregates, which possibly modified the distribution of polymer chains in the system, had an essential impact on the properties of blends with ODA, making a less rigid material with lower glass transition temperature (Tg), lower optical gap energy, and higher refractive index.

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This study presents an innovative methodology for real-time prediction of the lower heating value (LHV) of fuel gases in petrochemical plants using Poisson regression. The approach combines statistical tools and phenomenological concepts to optimize energy consumption in thermal cracking furnaces. Thirty-two laboratory samples were used to analyze the gas composition, density, and LHV. Statistical analysis, through Pearson correlation coefficients, identified the key components affecting the LHV. The predictive model developed, based on Poisson regression with a logarithmic link function, showed an average error of only 0.32%, standing out in accuracy compared to other methodologies such as simple linear regression and principal component analysis (PCA). The application of this methodology can result in significant financial and operational benefits, providing a better understanding of the process conditions that affect combustion efficiency. Additionally, the methodology allows for precise adjustments in cracking furnaces, ensuring safe and efficient operation. This work contributes to reducing energy consumption and greenhouse gas emissions in the petrochemical industry, promoting more sustainable and efficient practices.

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Brazil has the world’s largest reserve of niobium (~98%) which turns niobium compounds into extremely interesting materials from a strategic point of view in the country. Niobium pentoxide is an n-type semiconductor that presents interesting physical and mechanical properties. The presence of polymorphic phases on Nb2O5 powders has several implications from the scientific and application point of view. It is known that the H-phase is thermodynamically stable and can be obtained easily from amorphous Nb2O5 after heat treatment. In this work, niobic acid (Nb2O5.nH2O) produced by the Brazilian company CBMM has been used as the starting material to grow unique monoclinic P2 space group H-Nb2O5 crystals through a simple calcination route. The obtained material has been characterized by XRD (X-ray diffraction), SEM (scanning electron microscopy), TEM (transmission electron microscopy) and micro-Raman and submitted to cyclic voltammetry measurements. The characterization results confirm that H-Nb2O5 crystallized in the monoclinic P2 space group.

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Innovations in biodiesel purification pave the way for lower production costs and a more sustainable future. This study explores the remarkable potential of biodiesel boiler waste plants, both directly and in modified forms, for the purification process of soy methyl biodiesel (BMS). It extends to the inclusion of waste frying oil (ORF) samples. The untreated and HCl-treated biomass underwent a thorough characterization utilizing simultaneous thermogravimetry-differential thermal analysis (TG-DTA) and thermogravimetric-differential scanning calorimetry (TG-DSC) coupled with Fourier transform infrared spectroscopy (FTIR), infrared spectroscopy, X-ray fluorescence (EDX), and inductively coupled plasma optical emission spectroscopy (ICP OES). FTIR and EDX analyses revealed a significant presence of SiO2 in the biomass, which can effectively regulate moisture and reduce impurities during biodiesel production. Acidity, saponification value, water, and ester content were measured to assess the role of the residue in biodiesel purification. Both untreated and HCl-treated waste showed impressive efficiency in water adsorption and removing organic impurities in ORF and BMS. This confirms that boiler ash derived from rice husk fuel is a powerful adsorbent for impurities such as water and organic compounds in BMS and ORF, showing great promise as a reusable resource in biodiesel production facilities.

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With increasing recognition of the importance of biomonitoring in tropical estuaries, this study investigates the potential of oysters in assessing environmental contamination. This study assessed the mangrove oyster Crassostrea brasiliana as a biomonitor of estuarine contamination by metals (Al, Fe, Mn, Zn, Cu, Pb, Cd, Cr) in the Paciência river estuary on the Amazonian Equatorial coast. Oysters were collected across varying salinity gradients and seasons (dry and rainy). Results revealed seasonal and spatial fluctuations in water quality parameters. In situ measurements were taken to determine the environmental parameters of surface and bottom water, including salinity, temperature, and dissolved oxygen (DO). Oysters accumulated higher levels of Al, Fe, and Zn under low salinity conditions, while Cr, Cu (dry season), and Pb (rainy season) bioaccumulation increased with lower salinity and pH. Chromium and Zn bioaccumulations often exceeded Brazilian health standards, and a hazard index indicated potential health risks from consuming oysters from all sampling sites. Analysis of oysters from different regions showed that metal bioaccumulation is a widespread environmental challenge. This study highlights the effectiveness of C. brasiliana as a bioindicator for monitoring estuarine metal contamination.

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ASYMMETRIC ORGANOCATALYSIS: EVOLUTION AND COMPUTATIONAL APPLICATIONS IN SYNTHETIC ORGANIC CHEMISTRY. The use of organic molecules to catalyze chemical reactions was an important milestone in the long history of synthetic organic chemistry. These molecules, organocatalysts, can act in different ways, either by forming bonds with substrates or by non-covalent interactions. Important aspects of the mechanism of organocatalyzed transformations have been elucidated by combining experimental and computational studies. While the experiments provided the facts, the theoretical studies allowed them to be understood at a molecular level, while at the same time suggesting new pathways to investigate. The structural modification of these molecules makes it possible to precisely adjust the steric and electronic aspects involved in the selectivity of organocatalyzed reactions. The use of statistical tools has stood out as an efficient way of guiding these modifications. Here we present a brief history of organocatalyzed transformations, from the earliest reports to modern transformations, with particular emphasis on work that has used computational tools. We revisit the main elements of the study of reaction mechanisms by computational means, presenting an overview of the available tools and their domain of applicability. Finally, we discuss, using examples, fundamental questions about the use of statistical models to optimize organocatalyzed reactions.

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In recent years, non-traditional educational activities in the classroom have become increasingly common to motivate and engage students to study subjects considered difficult to learn. This experience report describes one of these hybrid activities, integrating digital games and low-cost materials like party balloons, rubber bands, and pins in a fun environment in the classroom as a strategy to promote learning and interaction between Brazilian undergraduate and 12th-grade students who evaluated it positively. Specifically, the activity described used two digital games on the stereochemistry and nomenclature of organic compounds. Still, it can also be applied by using any games that cover other subjects.

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This paper presents a Chemistry Team Game Tournament (TGT) as a didactic strategy to review stereochemistry concepts. For this purpose, a multilingual (English, Italian, French, and Portuguese) educational game, Stereochemistry Race, was developed on the online digital platform PlayingCards. The study involved the participation of 85 students from the following institutions: sixteen first-year Pharmacy students at the Federal University of Ceará (Brazil); twelve senior high school students at Colégio Maximus, in Fortaleza (Brazil); sixteen first-year Natural Sciences students and forty-one first-year Biotechnology students at the Università degli Studi di Genova (Italy). After the implementation of the tournament, the students evaluated the game, the match strategy, and their social and emotional interactions with their peers. To this end, data collection was carried out using a form that also included the UES-SF (User Engagement Scale-Short Form) engagement assessment model, which showed greater student participation and interest in stereochemistry studies than to traditional review classes.

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SCIENTIFIC DENIALISM: AN ANCIENT AND PERSISTENT PRACTICE THROUGHOUT HISTORY. The search for scientific truth has long been the target of denialism, which obstructs progress and demands perseverance from those advocating new discoveries. While subjective preferences in fields such as literature, music, and the arts may lead to favoring works from the past, in science, denialism hampers advancement. This study highlights the persistence of scientific denialism across various fields, from the opposition to the new Gregorian calendar, the denial of Lavoisier’s combustion theory, Berthelot’s rejection of atomism, and resistance to van’t Hoff’s three-dimensional molecular structures, to recent opposition to covid-19 vaccines and the patronage of quackery during the pandemic. These cases, drawn from both universal and national histories, illustrate how such resistance to science has spanned centuries and continues to affect scientific progress.

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In this paper, we present the study-case of the open innovation program Mining Lab Beginnings (MLB), from Nexa Resources, to connect university-industry. The MLB program proposes technological challenges and searches for technologies in very early-stage (“ideas”, technology readiness level (TRL) 1-2) from academic researchers. After mapping and selecting early-stage technologies throughout Brazilian Universities, Nexa finances a collaborative development of the ideas which significantly increases the chances of success. In the MLB, the initial challenge was the “Development of viable products from the jarosite waste” with 37 solutions mapped from universities, of which 6 were tested in the lab to reach TRL 3-4 (Phase 1) to prove the technical and preliminary economic feasibility. The academic teams received technical support and weekly mentoring throughout this phase. From this Phase 1 - Lab, 3 technologies were selected for the “Go-to-Market” (Phase 2) to reach TRL 6-7, focused on product development in relevant environment. After these phases, Nexa started the implementation of 2 technologies in an operational plant for the conversion of jarosite into two products. Moreover, one of the technologies is currently being transferred to another company. The MLB exemplifies how open innovation strengthens cooperation between universities-industry and promotes innovation.