Artigos - Química - FC

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Eco-friendly polymers based on Baru vegetable oil and fumaric acid using photopolymerization
(2023-06-01) Magri, Raquel [UNESP]; Gaglieri, Caroline [UNESP]; Alarcon, Rafael Turra; dos Santos, Gabriel Iago [UNESP]; Bannach, Gilbert [UNESP]; Universidade Estadual Paulista (UNESP); Universidade de São Paulo (USP)
Biomass-derivative materials are one of the answers to substitute materials from finite sources in the coming decades. Thus, the present paper demonstrates the syntheses of new polymers based on epoxidized Baru oil and fumaric acid by photopolymerization, which were investigated by incorporating different proportions of urethane dimethacrylate using ultraviolet and blue lights. The monomers and polymers were characterized by spectroscopic, thermal, and mechanical analyses. The incorporation of acrylate derivatives into the monomeric mixture increases the reactivity of monomers, achieving conversions >98% in both irradiation sources. Besides all polymeric materials presented thermal stability above 200 °C, they were transparent films that were able to remove some dyes from water, resulting in luminescent materials. In addition, the degradation processes of these polymers can be accelerated by organic solvents. Based on these properties, it is suggested that these eco-friendly polymeric materials can be used as coating, due to their partial transparency, and also for application in colored polymeric matrices, as well as dye remover in aqueous systems.
A screening process for carbonation of vegetable oils using an aluminum(salen) complex with a further application as weldable polymers
(2023-06-20) Alarcon, Rafael T. [UNESP]; Lamb, Katie J.; Cavalheiro, Éder T. G.; North, Michael; Bannach, Gilbert [UNESP]; Universidade de São Paulo (USP); Universidade Estadual Paulista (UNESP); University of Sheffield; Green Chemistry Centre of Excellence
Carbon dioxide (CO2) occurs naturally, though its emissions have been increasing due to anthropogenic activities, and its increasing atmospheric concentration levels are causing a greenhouse effect. In efforts to develop new carbon dioxide utilization (CDU) methodologies, the catalyzed reaction of CO2 with epoxidized vegetable oil, obtained from Brazilian macaw oil and Baru oil, to form carbonated oils for novel and sustainable monomers was explored. A screening process is carried out to develop the best reaction conditions, by varying catalyst/cocatalyst loading, reaction time, CO2 pressure, and the reaction temperature, resulting in conversions of 100%. The aluminum(salen) complex shows a selective and efficient catalyst activity. Both carbonated oils are reacted with amines (1,6-diaminohexane, lysine, and 4,4′-methylenebis [cyclohexylamine]) to provide weldable polyhydroxyurethanes. Polymers synthesized from lysine provide a more selective reaction and higher cross-linked structures, with fewer side reactions involving the glyceride groups. All the synthesized polymers are thermally stable above 200°C and differential scanning calorimetry (DSC) analysis shows two main thermal events, related to the glass transition (Tg) and the topology-freezing transition temperature (Tv). The Tv result indicates that the polymer has weldable properties due to chemical bond exchange. Thus, these polymers can be healed into different shapes upon exposure to red light (660 nm).
A flaw in applying the FRET technique to evaluate the distance between ligands and tryptophan residues in human serum albumin: Proposal of correction
(2023-05-01) Povinelli, Ana Paula Ribeiro; de Carvalho Bertozo, Luiza [UNESP]; Zazeri, Gabriel; Ximenes, Valdecir Farias [UNESP]; Universidade Estadual de Campinas (UNICAMP); Universidade Estadual Paulista (UNESP)
Due to its primordial function as a drug carrier, human serum albumin (HSA) is extensively studied regarding its binding affinity with developing drugs. Förster resonance energy transfer (FRET) is frequently applied as a spectroscopic molecular ruler to measure the distance between the binding site and the ligand. In this work, we have shown that most of the published results that use the FRET technique to estimate the distance from ligands to the binding sites do not corroborate the crystallography data. By comparing the binding affinity of dansyl-proline with HSA and ovotransferrin, we demonstrated that FRET explains the quenching provoked by the interaction of ligands in albumin. So, why does the distance calculation via FRET not corroborate the crystallography data? We have shown that this inconsistency is related to the fact that a one-to-one relationship between donor and acceptor is not present in most experiments. Hence, the quenching efficiency used for calculating energy transfer depends on distance and binding constant, which is inconsistent with the correct application of FRET as a molecular ruler. We have also shown that the indiscriminate attribution of 2/3 to the relative orientation of transition dipoles of the acceptor and donor (κ2) generates inconsistencies. We proposed corrections based on the experimental equilibrium constant and theoretical orientation of transition dipoles to correct the FRET results.
Chemiluminescent oxidation of 2-methylindol catalyzed by cobalt(II)
(2023-06-01) Silva Silveira, Victória Helloiza [UNESP]; de Camargo, Marcela Rodrigues [UNESP]; Rocha, Camila Loreta; Cardoso, Carmen Lúcia; Ximenes, Valdecir Farias [UNESP]; Universidade Estadual Paulista (UNESP); Universidade de São Paulo (USP)
Chemiluminescence is the emission of light from a chemical reaction. Due to its intrinsic selectivity and sensitivity, chemiluminescent reactions are widely applied to detect biological and nonbiological analytes, including transition metal ions. This work presents the study and development of a chemiluminescent reaction mediated by cobalt(II). We found that cobalt(II) is an efficient catalyst for the oxidation of 2-methylindol (2-MI) by hydrogen peroxide (H2O2). The oxidation produced intense and long-lasting chemiluminescence. The selectivity to 2-MI was attested by comparing it with other indole derivatives. The light emission elicited by the oxidation of 2-MI was two orders of magnitude higher than the reaction using the isomer 3-methylindol (3-MI). A relationship between the exclusive formation of indoxyl dimers for the oxidation of 2-MI and not for 3-MI explained the specificity. The reaction was also selective regarding the metal ion used as a catalyst, as attested by comparing cobalt(II) with nine other transition metals, which were not able to promote light emission. The reaction was optimized regarding the pH, buffer constituents, and H2O2 concentration. The detection limit of Co2+ was 0.15 μM. Superoxide radical anion was generated in the reaction course and is involved in light emission efficiency. In conclusion, these findings open new perspectives for metal ion-catalyzed chemiluminescent reactions.
Silver nanoparticles in denture adhesive: An antimicrobial approach against Candida albicans
(2023-04-01) Peralta, Laura Catalí Ferreira; Almeida, Nara Ligia Martins; Pontes, Fenelon Martinho Lima [UNESP]; Rinaldo, Daniel [UNESP]; Carneiro, Camila Alves; Neppelenbroek, Karin Hermana; Lara, Vanessa Soares; Porto, Vinicius Carvalho; Universidade de São Paulo (USP); Universidade Estadual Paulista (UNESP)
Objective: To evaluate the antimicrobial potential of silver nanoparticles (Ag NPs) synthesized using three different routes (ultraviolet light, Turkevich, and green chemistry method using Glycine max extract) associated with COREGA® denture powder adhesive. Methods: Heat-cured acrylic resin specimens were treated with different Ag NPs associated with the adhesive (AD + Ag UV, AD + Ag Turk, and AD + Ag Gm groups). As controls, the specimens were treated with a combination of adhesive and nystatin (AD + Nyst group), only adhesive (AD group), or submerged on the surface of the specimens (PBS group). After the treatments, biofilms of C. albicans developed for 3, 6, and 12 h on the specimen surfaces. The biofilm was quantified using colony-forming units per milliliter, colorimetric assay, and confocal laser scanning microscopy. Results: Regardless of the period, we observed an inhibition of fungal load and a reduction in metabolic activity and biofilm mass in the resin specimens treated with the combinations AD/Ag NPs, compared to AD and PBS. The antimicrobial action of the AD + Turk and AD + Ag Gm groups was similar than that for the AD + Nyst group in all periods and viability tests, except for the biofilm mass (12 h). Conclusions: The COREGA® adhesive with Ag NPs, mainly those synthesized using the Turkevich and Glycine max methods, showed excellent antimicrobial activity against C. albicans biofilms, maintained for up to 12 h. Clinical significance: The association of Ag NPs to the adhesive can add preventive or therapeutic effects against denture stomatitis, to this prosthetic material.
Biosynthesis of silver nanoparticles of Tribulus terrestris food supplement and evaluated antioxidant activity and collagenase, elastase and tyrosinase enzyme inhibition: In vitro and in silico approaches
(2023-03-01) Figueiredo, Célia Cristina Malaguti [UNESP]; da Costa Gomes, Amanda [UNESP]; Zibordi, Laura Camargo [UNESP]; Granero, Filipe Oliveira [UNESP]; Ximenes, Valdecir Farias [UNESP]; Pavan, Nathalia Mariana [UNESP]; Silva, Luciana Pereira; Sonvesso, Cibely da Silva Martin [UNESP]; Job, Aldo Eloizo [UNESP]; Nicolau-Junior, Nilson; Silva, Regildo Márcio Gonçalves da [UNESP]; Universidade Estadual Paulista (UNESP); Fundação Educacional do Município de Assis (FEMA); Universidade Federal de Uberlândia (UFU)
Food supplements from plants are source of many antioxidant substances. Tribulus terrestris food supplement (TtFS) is highlighted as one of these supplements that has presented potential to prevent damages and diseases caused by oxidative stress. In addition, new formulations that enhance the benefits of food supplement have been developed and metallic nanoparticles, the so-called green synthesis, has been of great interest. UV–visible spectroscopy, energy dispersive spectroscopy (EDS), Zeta potential (ZP), scanning transmission electron microscopy (STEM), scanning electron microscope (SEM) were used to characterize the synthesized silver nanoparticles (AgNPs). Antioxidant activity was determined by DPPH radical scavenging, ferric ion reducing power (FRAP); ABTS radical scavenging, and oxygen radical absorption capacity (ORAC-FL). Molecular docking analyses were performed to evaluate molecular interactions. Antioxidant evaluation of TtFS demonstrated 83.6% antioxidant activity (DPPH), 714.82 μM Trolox Equivalent (TE)/g sample (FRAP), 91.24 μM TE/g sample (ABTS), and antioxidant activity in ORAC assay. It presented inhibition activity on collagenase (75.33%), elastase (54.04%) and tyrosinase (59.07%). In addition, in silico assays showed an interaction between T. terrestris steroidal saponins and DNA, and the highest DNA binding affinity was observed with protodioscin. Steroidal saponins also presented interaction with all enzymes evaluated. The characterization of AgNPs demonstrated that they were formed as a spherical shape. These AgNPs showed greater protective properties against oxidative stress (85.41% antioxidant activity (DPPH) and 957.55 μM TE/g sample (FRAP)). The results represent an important indicator for the development and discovery of new nanoestructured pharmaceutical and cosmetic formulation using plants and natural products.
Vegetable oils as monomeric and polymeric materials: A graphical review
(2022-01-01) Gaglieri, Caroline [UNESP]; Alarcon, Rafael T.; de Moura, Aniele [UNESP]; Bannach, Gilbert [UNESP]; Universidade Estadual Paulista (UNESP); Universidade de São Paulo (USP)
Vegetable oils have been extensively researched, and many reviews have been published about them. However, most of them are focused on soybean and linseed oils and reactions, such as epoxidation, but do not take into account other potential sources or reactions that can provide high value products. Therefore, the present work aims to cover these overlooked topics illustrating different sources of vegetable oils including baru, macaw, andiroba, grape, passion fruits, neem, and so on. Furthermore, some chemical modifications and their resulting monomers are discussed, for instance, maleinization, epoxidation, acrylation, carbonatation, and click chemistry, and forth. Consequently, there are several ways to use vegetable oils to produce renewable polymers for use in technological fields, such as photopolymerisation and vitrimers. The latter has received great attention in recent research due to their recovering, reshaping, and welding properties.
Analysis of the Pb0.30CaxSryTiO3 ternary system: The effect of Ca2+ and Sr2+ cations on the electrical properties of PbTiO3
(2022-01-01) Gouveia, Amanda Fernandes; Ribeiro, Lara Kelly; Assis, Marcelo; Longo, Elson; Andrés, Juan; Pontes, Fenelon Martinho Lima [UNESP]; University Jaume I; Universidade Federal de São Carlos (UFSCar); Universidade Estadual Paulista (UNESP)
Powder and thin films of the Pb0.30Ca0.10Sr0.60TiO3 (PCST 30/10/60) and Pb0.30Ca0.60Sr0.10TiO3 (PCST 30/60/10) ternary system were synthetized by the polymeric precursor method and the thin films deposited on the Si/SiO2/Ti/Pt substrate. The effects of the Sr2+ and Ca2+ cations substitutions on the electrical and structural properties of the PbTiO3 were characterized by X-ray diffraction, Infrared, and Raman spectroscopy. Theoretical calculations were performed using the CRYSTAL06 program associated with the density functional theory and the B3LYP functional hybrid. Structural and electronic properties of the system were analyzed. The band gap values calculated for the PCST 30/10/60 and PCST 30/60/10 models were 3.35 and 3.41 eV, respectively. The results showed an evolution to a greater symmetry in the direction to the cubic SrTiO3 structure and the phase transition was characterized by the Curie temperature dependence. The broad bands above FE-PE phase transition temperature suggest a phase transition diffuse type. It is explained by a local symmetry disorder due to a higher Sr2+ and Ca2+ cations concentration in the PbTiO3 host lattice.
Synthesis and deposition of bismuth oxychloride with a rose-type flower shape and photoelectroactivity evaluation in the methyl orange discoloration reaction
(2023-01-01) Pelissari, Marcelo Rodrigues da Silva [UNESP]; Pereira Camargo, Luan; Pontes, Fenelon Martinho Lima [UNESP]; Dall'Antonia, Luiz Henrique; Universidade Estadual Paulista (UNESP); Universidade Estadual de Londrina (UEL); INCTBio—National Institute of Science & Technology in Bioanalytic
In this work, bismuth oxychloride with a rose-type flower shape was successfully synthesised using the easy and low-cost successive ionic layer adsorption and reaction process. The tetragonal crystalline structure with a flower-like shape and thickness of 150-nm nanosheets was used as electrode material in an exciting approach for the photoelectrochemical discoloration reaction of methyl orange. The structure, morphology and optical properties of the obtained bismuth oxychloride sample were evaluated through X-ray diffraction, Raman spectroscopy, the Brunauer–Emmett–Teller method, diffuse reflectance ultraviolet–visible spectroscopy and scanning electron microscopy. Through photoelectrochemical characterisation measurements (linear sweep voltammetry, chronoamperometry and electrochemical impedance spectroscopy techniques), the bismuth oxychloride electrode showed remarkable electroactivity under ultraviolet light irradiation. The methyl orange discoloration reaction, performed under ultraviolet light incidence and potential application of −0.5 V (vs silver/silver chloride) for 60 minutes, produced a higher degradation percentage (ca. 82%) and kobs of 29 × 10−3 min−1.
Production of bovine hydroxyapatite nanoparticles as a promising biomaterial via mechanochemical and sonochemical methods
(2023-02-01) Ferrairo, Brunna Mota; Mosquim, Victor; de Azevedo-Silva, Lucas José; Pires, Luara Aline; Souza Padovini, David Santos [UNESP]; Magdalena, Aroldo Geraldo [UNESP]; Fortulan, Carlos Alberto; Lisboa-Filho, Paulo Noronha [UNESP]; Rubo, José Henrique; Sanches Borges, Ana Flávia; Universidade de São Paulo (USP); Universidade Estadual Paulista (UNESP)
This study aimed to evaluate the effectiveness of sonochemical and milling nanoparticulate techniques using HA of bovine origin. The starting powders were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDX), and transmission electron microscopy (TEM) (75 μm). Sonication was performed with 40% of the maximum amplitude (750 W) and 20 Hz in an aqueous solution (4 h). The milling technique used a polyethylene jug loaded with 40 vol% milling elements placed in a rotatory mill (104 rpm, 48 h), then in a vibratory mill (72 h). The results revealed that the final average grain size of HA was 40 nm for the milling technique and 60 nm for the sonication (TEM). FTIR analysis showed a broad band at 1300–500 cm−1, and similar peaks without HA bond degradation, regardless of the two forms of HA nanoparticles. XRD analysis showed peaks equivalent to those of synthetic and animal HA. In addition, the equivalence between the method peaks demonstrated non-degradation of structural. The same chemical characteristics between groups were also observed in the EDX samples. We concluded that both methods were able to decrease the size of particles preserving the crystal structure, but the milling method produced smaller particles.
Effect of Isomerization and Copolymerization of Itaconic Anhydride During the Synthesis of Renewable Monomers Using Vegetable Oils
(Soc Brasileira Quimica, 2022-10-27) Gaglieri, Caroline [UNESP]; Alarcon, Rafael T.; Moura, Aniele de [UNESP]; Magri, Raquel [UNESP]; Rinaldo, Daniel [UNESP]; Bannach, Gilbert [UNESP]; Universidade Estadual Paulista (UNESP); Universidade de São Paulo (USP)
Vegetable oils are alternatives to producing renewable monomers since they are biomass. It is possible to react them with anhydrides by heating to provide monomers with high reactivity. However, after the reaction of grape seed oil with itaconic anhydride, it was observed the occurrence of parallel reactions that had not been observed when the same oil was reacted with maleic anhydride. Some articles in the literature have reported that temperature and bases can isomerize itaconic anhydride into citraconic anhydride, which is more stable at room temperature. However, they have not focused on completely understanding how this phenomenon occurred nor studied it in processes that involve microwave irradiation. Therefore, this paper presents a complete characterization and investigation about the thermal behavior of itaconic anhydride and how it can affect the monomer synthesis performed under heating.
Concomitant binding of two fluorescent probes at site-I of human serum albumin: The protein acting as a scaffold enabling fluorescence resonance energy transfer
(2022-09-01) Ximenes, Valdecir Farias [UNESP]; Universidade Estadual Paulista (UNESP)
Human serum albumin (HSA) is the primary drug carrier in the blood plasma. Here, I aimed to show that two ligands can be accommodated simultaneously in the binding site-I of HSA. To do so, I studied the interaction inside the protein among site-I ligands of HSA via fluorescence resonance energy transfer (FRET), synchronous fluorescence, red edge excitation shift (REES), and induced circular dichroism (ICD). Warfarin (WAR), coumarin-153 (C153), 6-(p-toluidino)-2-naphthalenesulfonic acid sodium salt (TNS), dansylglycine (DGY), and 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) were enrolled in the investigation. I found that WAR can transfer energy to C153 only in the presence of the protein. In addition, the presence of WAR at site-I altered the protein microenvironment felt by C153. The alteration was detected by measuring the synchronous fluorescence, REES, and ICD in C153. The findings were validated by measuring the energy transfer from TNS to DCM and the alteration in synchronous fluorescence and REES. FRET was not observed using WAR as donor and DGY as acceptor. The result is consistent, as DGY is a site-II ligand at a higher WAR distance. In all studied cases, the effects were only observed in the presence of HSA. In conclusion, the protein acted as a scaffold approximating the ligands. These findings prove that more than one ligand can simultaneously be complex at site-I of HSA.
Development of fluorescent azapentalenes to study the reactivity of hypochlorous acid and chloramines in micellar systems
(2022-11-01) Pavan, Nathália Mariana [UNESP]; Martins, Lucas Michelão [UNESP]; Augusto, Laís Cristina [UNESP]; da Silva-Filho, Luiz Carlos [UNESP]; Ximenes, Valdecir Farias [UNESP]; Universidade Estadual Paulista (UNESP)
Hypochlorous acid (HClO) is an endogenous reactive oxygen species generated by the oxidation of chloride catalyzed by myeloperoxidase (MPO). This enzyme is abundant in polymorphonuclear cells and involved in the human innate immune function. This work presents the development of a fluorescent azapentalene (C1) able to be incorporated in micelles and susceptive to HClO due to its sulfide moiety. C1 is non-fluorescent in the aqueous medium but fluoresces when incorporated in micelles produced by surfactants such as sodium dodecyl sulfate (SDS), Triton X-100, and cetyltrimethylammonium chloride (CTAC). The addition of HClO promoted instantaneous fluorescence decay of C1 incorporated in SDS but not in Triton X-100 or CTAC, showing the higher accessibility of HClO to the SDS micelle core. The reactivity of C1 was also studied in the presence of amine compounds taurine, 4-aminobutanoic acid (GABA), and its ethyl ester (GABA-EE), leading to the formation of the respective chloramines. The reactivity increased with the GABA-EE, evidencing the higher accessibility to the micellar core due to the hydrophobic character of the ester derivative. The potentiality of the system to monitor the enzymatic production of HClO was demonstrated by using MPO and hydrogen peroxide (H2O2). Scavengers of HClO were applied to validate the method. In conclusion, applying C1 opens new possibilities for studying the biochemical properties of HClO and chloramines in micelles.
Antioxidant and antiglycation activities and inhibitory action of Passiflora cincinnata on collagenase, elastase and tyrosinase: in vitro and in silico study
(2022-09-01) da Costa Gomes, Amanda [UNESP]; Figueiredo, Célia Cristina Malaguti [UNESP]; Granero, Filipe Oliveira [UNESP]; Junior, João Luiz Bronzel [UNESP]; Ximenes, Valdecir Farias [UNESP]; Silva, Luciana Pereira; Nicolau-Junior, Nilson; da Silva, Regildo Márcio Gonçalves [UNESP]; Universidade Estadual Paulista (UNESP); Fundação Educacional do Município de Assis (FEMA); Universidade Federal de Uberlândia (UFU)
Passiflora species are widely used in folk medicine due to their sedative and anxiolytic activities; however, scientific studies also showed different biological activities (antioxidant, anti-inflammatory, antidiabetic and antimicrobial). The present study aimed to characterize the phytochemical profile of P. cincinnata hydroethanolic extract, evaluate its antioxidant and antiglycation activities and evaluate in silico molecular docking of its main flavonoids. Phytochemical characterization was performed by quantification of total polyphenols and flavonoids content, and High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS) analysis. Antioxidant activity was determined by 2,2-Diphenyl-1-picrylhydrazyl (DPPH), Ferric reducing antioxidant power (FRAP), Nitric oxide (NO) and Thiobarbituric acid reactive species (TBARS) tests. Antiglycation activity was determined by Relative Electrophoretic Mobility (REM) and free amino groups assays. P. cincinnata presented total polyphenols (62 mg gallic acid equivalent (GAE) g−1 dry weight (DW)) and flavonoids (57 mg rutin equivalent (RE) g−1 DW), besides HPLC-MS showed the presence of different flavonoids glucoside, mainly vitexin and orientin. The extract presented antioxidant activity by DPPH (76.60%), FRAP (276.70 μM trolox equivalent (TE) g−1 DW), TBARS (80.30% inhibition) and NO (10.10 μM mL−1 nitrite formed). REM demonstrated that extract presents antiglycation activity similar to Bovine serum albumin treated with Aminoguanidine; additionally, it showed 22% free amino groups. In silico assay demonstrated that orientin exhibited the highest interaction with DNA and the best docking score with elastase and collagenase. Therefore, the present study showed the protective properties of P. cincinnata hydroethanolic extract against oxidative stress and glycation. It also showed the presence of polyphenols and flavonoids, and their interaction with DNA and enzymes.
Antiglycation, antioxidant and cytotoxicity activities of crude extract of Turnera ulmifolia L. before and after microencapsulation process
(2022-09-20) Viel, Amanda Martins [UNESP]; Figueiredo, Célia Cristina Malaguti [UNESP]; Granero, Filipe Oliveira [UNESP]; Silva, Luciana Pereira; Ximenes, Valdecir Farias [UNESP]; Godoy, Thais Miranda; Quintas, Luis Eduardo Menezes; Silva, Regildo Márcio Gonçalves da [UNESP]; Universidade Estadual Paulista (UNESP); Fundação Educacional do Município de Assis (FEMA); Universidade Federal do Rio de Janeiro (UFRJ)
Turnera ulmifolia L. is used in folk medicine and it is known to have anti-hyperglycemic effect on the organism in order to reduce complications in diabetic patients. Glycation process is directly related to oxidative stress, acting as an important endogenous source, inducing the production of free radicals, and thus increasing the production of reactive oxygen species. The encapsulation technology on natural compounds can minimize and even mitigate the risk of loss of biological activity in order to maintain their activities against oxidative stress and glycation. The present study aimed to evaluate the antiglycation and antioxidant activities of T. ulmifolia extract before and after encapsulation and cytotoxicity of the crude extract. This study presents important information about the biological activities, highlighting antioxidant and antiglycation potential and no cytotoxicity of Turnera ulmifolia crude extract, a species of genus Turnera that has been poorly studied. T. ulmifolia crude extract presented flavonoids as main active compounds. The results showed a promising activity in scavenging free and peroxyl radicals, chelating iron ions and inhibiting BSA glycation. In addition, this study showed the possible encapsulation of bioactive compounds using maltodextrin as wall material.
Development of renewable thermosetting polymers based on grape seed oil derivatives
(2022-01-01) Gaglieri, Caroline [UNESP]; Alarcon, Rafael Turra [UNESP]; Magri, Raquel [UNESP]; North, Michael; Bannach, Gilbert [UNESP]; Universidade Estadual Paulista (UNESP); The University of York
The demand for polymeric materials increases year by year, and most of them are derived from nonrenewable sources, and their consume has been increasing year by year. Therefore, there is a demand for research on bioderived polymers that are viable to be produced on an industrial scale. Based on the lack of polymers produced exclusively using monomers derived from vegetable oils, this paper shows the syntheses of renewable thermosetting polymers derived exclusively from grape seed oil, which is a by-product from the wine and grape juice industries. After the evaluation of the effect of using or not catalyst, it was determined that increasing 1-methylimidazole amount in the monomer mixture provides the decreasing of parallel reactions. However, thermal and mechanical properties, as well as the crosslinking density of polymers do not change significantly using 1.0% or 5.0% of catalyst (the minimal amounts needed to favor the esterification). Based on the characterization, the final polymers are not favorable in applications that require high mechanical impacts. However, they would be excellent as coatings due to their elevated crosslinking density, hydrophobic properties and homogenous surface. In addition, based on the properties observed under UV-light, they can also be used as luminescent materials.
MICROLEARNING AS A TOOL FOR SCIENTIFIC DISSEMINATION: THERMAL ANALYSIS OF THE PORTUGUESE GOOD LUCK ROOSTER
(2022-01-01) Magri, Raquel [UNESP]; Gaglieri, Caroline [UNESP]; Alarcon, Rafael Turra [UNESP]; de Souza, Aguinaldo Robinson [UNESP]; Bannach, Gilbert [UNESP]; Universidade Estadual Paulista (UNESP)
This work aims to produce and disseminate videos that follow the microlearning methodology, to explain the physicochemical properties of cobalt (II) chloride hexahydrate through thermal analysis, and to determine the reliability of the Portuguese good luck rooster. Temporal and social accelerations due to the growth of the technological world are changing the old teaching-learning methodologies; thus, new methods should be explored. In the microlearning methodology, short segments and specific content can be broadcast to anyone at any time. In addition, relating new information to individual’s experiences can favor the teaching-learning process. The good luck rooster is an ornament of Portuguese origin, which can forecast the weather in a limited way, and is composed of cobalt (II) chloride hexahydrate. This compound was characterized by TG-DTA (Simultaneous Thermogravimetry-Differential Thermal Analysis) and DSC (Differential Scanning Calorimetry), verifying that the salt loses its hydration water when exposed to high temperatures, changing its color from pink color to blue.
Study of simultaneous adsorption efficiency of metals using modifiorganic and synthetic adsorbents
(2022-01-01) Leandro-Silva, Emerson [UNESP]; Pipi, Angelo Ricardo Favaro; Magdalena, Aroldo Geraldo [UNESP]; Piacenti-Silva, Marina [UNESP]; Universidade Estadual Paulista (UNESP); Dublin City University
Water contamination by heavy metals represents a high risk of environmental pollution and a precursor of several human diseases. The presence of these metals at high levels in wastewater treatment plants and industrial effluents motivated the search for remediating these pollutants. Among remediation methods, adsorption is extensively used to decontaminate waters containing these metals. Thus, this study prepared, characterized, optimized, and applied two types of adsorbents to a prepared metal ion solution (PMS): a bioadsorbent based on banana peel flour (BPF) and a synthetic adsorbent based on magnetite encapsulated by chitosan (MEC). A systematic study was performed with PMS containing Al (III), Ba (II), Pb (II), Cu (II), Cr (III), Fe (II), Mn (II), and Zn (II) to determine the best conditions for simultaneous metal ion adsorption Adsorption studies evaluated the experimental adsorption isotherms according to the variation in pH values, the mass of adsorbents, and contact time, and the kinetic study applied pseudo-first-and pseudo-second-order models. The best parameters were the pH of 6, a mass of adsorbents of 25 mg, and fast saturation time of around 10 minutes. The kinetic model that best fitted the process was the pseudo-second-order for all metals in both adsorbents. The PMS adsorption capacity achieved by MEC was higher than BPF. The removal by MEC was Al=Fe=Pb=Cu=Cr> Zn>Mn>Ba, in the percentages of 100, 100, 100, 100, 100, 98, 88, and 76%, respectively. The BPF showed Pb>Fe>Cr>Cu>Al>Zn>Ba>Mn, in the percentages of 97, 67, 63, 50, 46, 45, 44, and 5%, respectively. The results suggest that the affinity between adsorbents with certain metal ions is due to the characteristics of the adsorbent surface and the number of chemical species available in the solution, which may interfere with the adsorptive process. Above all, the percentage of simultaneous removal of metal ions by both adsorbents was relevant, making them promising for remediating heavy metal ions in sanitary sewage after conventional treatment and industrial effluents containing mixed metal ions.
Creative Learning, Computational Thinking, and Robotics in Elementary Education
(Univ Nove Julho, 2022-01-01) Tercariol, Adriana Aparecida de Lima; Teixeira, Rosiley Aparecida; Barros, Daniela Melare Vieira [UNESP]; Souza, Aguinaldo Robinson de [UNESP]; UNINOVE; Universidade Estadual Paulista (UNESP); UAB
Nicotine as a Catalyst for Chlorination Promoted by Hypochlorous Acid: Experimental and Theoretical Studies
(Soc Brasileira Quimica, 2022-06-27) Ximenes, Valdecir F. [UNESP]; Pavan, Nathalia M. [UNESP]; Souza, Aguinaldo R. de [UNESP]; Barros, Gabriel A.; Morgon, Nelson H.; Universidade Estadual Paulista (UNESP); Universidade Estadual de Campinas (UNICAMP)
There is robust evidence of the hypochlorous acid (HClO)-mediated damage in biomolecules, and nicotine boosts the chlorination potency of HClO. We present experimental and theoretical evidence of the mechanism by which nicotine catalyzes the chlorination of pyranine. The rate constants for chlorination of pyranine by HClO were measured in the presence (5.3 x 10(5) mol(-1) L s(-1)) and absence of nicotine (4.2 x 10(3) mol(-1) L s(-1)), revealing the catalytic effect of the alkaloid. Density functional theory (DFT) calculations, based on B3LYP-GD3(BJ)/6-311++G(3df,2p)/SMD(Water)//B3LYP-GD3(BJ)/6-311++G(2d,p)/SMD(Water) level of theory, were performed and showed a decreased activation energy for chlorine transfer and hydrogen abstraction when nicotine chloramine intermediated the reaction. The atomic polar tensor (APT) charges on the chlorine atom of HClO (+0.084) were lower than the chlorine of nicotine chloramine (+0.149), revealing the higher electrophilic character of nicotine chloramine. In conclusion, the increased electrophilic nature of HClO provoked by nicotine explains its catalytic effect.

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