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Galactomannans (GM) are hemicellulosic polysaccharides composed of D-mannopyranose chains linked by ß (1 â†’ 4) glycosidic linkages with branches of D-galactopyranose linked by α (1 â†’ 6) linkages. This polysaccharide is recognized for its hydrophilic character, as it is rich in hydroxyl groups (-OH). This chemical characteristic, combined with the absence of ionic charges, enables structural modifications such as transesterification of the fatty acid chains (FA), which provides a strategy for obtaining amphiphilic structures. The enzyme-catalyzed syntheses were carried out in DMSO with GM decanoate (GMD) and GM palmitate (GMP) at different molar ratios (0.5 and 1.0) and the resulting structures were evaluated with infrared spectroscopy (FTIR), solid-state nuclear magnetic resonance (CP/MAS 13C NMR) and differential scanning calorimetry (DSC). The FTIR spectrum confirmed the transesterification of GM with the appearance of a C[bond, double bond]O band (1730-1750 cm-1). These results were confirmed by the signals observed at 177 and 30 ppm in the CP/MAS 13C NMR spectrum, which corresponded to the C[bond, double bond]O groups of the esters and the terminal -CH3 groups of the FA chains, respectively. Finally, DSC showed glass transition temperatures (Tg) in the range 43-51 °C, while the melting temperatures (Tm) of the GM esters (59 °C) were not affected by different degrees of esterification (DE) for GMD (0.37 and 0.71) and GMP (0.47 and 0.57).

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Novel four-coordinated boron complexes (1-5) were synthesized via a reaction between BF3·CH3OH and benzimidazole-phenolate ligands (L1-L5), which are N,O-donors. These complexes exhibit intense blue emission in the solution and solid states accompanied by notable fluorescence quantum yields (ΦF). The study of the structure-property relation, through theoretical and experimental approaches, revealed a distinctive trend where compounds incorporating electron-donating substituents (methyl and ethoxy groups) in the phenolate moiety manifest shifts in emission wavelengths across the blue spectrum, concomitant with an increase in ΦF. Furthermore, the incorporation of an aromatic ring into the benzimidazole moiety considerably intensifies the rate of radiative relaxation from excited states. Notably, in the solid phase, either as a crystalline powder or loaded into polymer films, these modified complexes maintain or even surpass ΦF values observed in molecular solutions, ranging from 0.18 to 0.57, depending on the substitution. This characteristic makes these compounds attractive for applications in optoelectronics. All of the compounds were characterized using 1H, 13C, 11B, and 19F NMR, elemental analysis, and the molecular structures were corroborated through single-crystal X-ray diffraction analysis. Computational calculations via time-dependent density functional theory further elucidate the tunability of optical bandgaps through group substitution on ligands, aligning well with experimental observations.

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Avocado paste (AP) is an industrial byproduct and a potential source of bioactive compounds, so there is great interest in its valorization. The objective of the present study was to evaluate the effects of adding AP to corn chips regarding their nutritional profile and sensory acceptability. Three AP-supplemented corn chip samples were prepared (C-2%, C-6%, and C-10%), along with a control chip (C), whose total phenolics, flavonoids, antioxidant capacity, proximate composition, minerals, fatty acids, and sensory acceptability were evaluated. Regarding the content of phenolic compounds and flavonoids, significant increases were found between all samples (p < 0.05), particularly between C and C-10% (from 0.93 to 3.56 mg GAE/g dw and 1.17 to 6.61 mg QE/g dw, respectively). Their antioxidant capacity also increased significantly (p < 0.05) with all methods used (FRAP, DPPH, ORAC, and TEAC). Regarding the sensory analysis, no significant differences were found (p > 0.05) between C and C-2% in the parameters of smell, color, flavor, and overall acceptability; however, the texture of C-2% was better evaluated. The C-2% sample also had the highest acceptability; 82% of the participants mentioned that they would buy the C-2%, higher than the rest of the samples. These results suggest the feasibility of adding 2% AP as a strategy to improve the nutritional properties of corn chips without compromising their sensory acceptability; therefore, AP may be used as a food ingredient.

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KEY MESSAGE: The miR822 together with of AGO9 protein, modulates monosporic development in Arabidopsis thaliana through the regulation of target genes encoding Cysteine/Histidine-Rich C1 domain proteins, revealing a new role of miRNAs in the control of megaspore formation in flowering plants. In the ovule of flowering plants, the establishment of the haploid generation occurs when a somatic cell differentiates into a megaspore mother cell (MMC) and initiates meiosis. As most flowering plants, Arabidopsis thaliana (Arabidopsis) undergoes a monosporic type of gametogenesis as three meiotically derived cells degenerate, and a single one-the functional megaspore (FM), divides mitotically to form the female gametophyte. The genetic basis and molecular mechanisms that control monosporic gametophyte development remain largely unknown. Here, we show that Arabidopsis plants carrying loss-of-function mutations in the miR822, give rise to extranumerary surviving megaspores that acquire a FM identity and divides without giving rise to differentiated female gametophytes. The overexpression of three miR822 putative target genes encoding cysteine/histidine-rich C1 (DC1) domain proteins, At5g02350, At5g02330 and At2g13900 results in defects equivalent to those found in mutant mir822 plants. The three miR822 targets genes are overexpressed in ago9 mutant ovules, suggesting that miR822 acts through an AGO9-dependent pathway to negatively regulate DC1 domain proteins and restricts the survival of meiotically derived cells to a single megaspore. Our results identify a mechanism mediated by the AGO9-miR822 complex that modulates monosporic female gametogenesis in Arabidopsis thaliana.

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Beryllium is a metallomimetic main-group element, i.e., it behaves similarly to transition metals (TMs) in some bond activation processes. To investigate the ability of Be compounds to activate C-X bonds (X = F-I), we have computationally investigated, using DFT methods, the reaction of (CAAC)2Be (CAAC = 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene) and a series of five-membered heterocyclic beryllium bidentate ligands with phenyl halides. We have analysed all plausible reaction mechanisms and our results show that, after the initial C-X oxidative addition, migration of the phenyl group occurs towards the less electronegative heteroatom. Our theoretical study highlights the important role of bidentate non-innocent ligands in providing the required electrons for the initial Ph-X oxidative addition. In contrast, the monodentate ligand, CAAC, does not favour this oxidative addition.

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Introducción: En las dos últimas décadas se han incrementado las publicaciones sobre el empleo del ácido tranexámico en diferentes especialidades quirúrgicas; entre ellas, la cirugía ortopédica y traumatológica. Objetivo: Demostrar la importancia del ácido tranexámico en la cirugía electiva y de urgencia en ortopedia y traumatología. Desarrollo: Se revisaron las bases de datos Pubmed/Medline, SciELO, BVS, Scopus, Ebsco y Cochrane. Se emplearon los descriptores "ácido tranexámico", "reducción del sangrado posoperatorio en ortopedia", "pérdida de sangre", "agentes hemostáticos", "riesgo de transfusión" y "manejo del politraumatizado". Fueron incluidos artículos originales de investigación, de revisión, guías terapéuticas, metaanálisis y editoriales. Conclusiones: Aunque algunos autores divergen en cuanto a la dosis adecuada de ácido tranexámico en ortopedia y traumatología, todos concluyen que este producto controla el sangrado en situaciones traumáticas y en cirugías electivas o de urgencia.

Introduction: Currently, publications on the use of tranexamic acid in different surgical specialties have increased; among them, orthopedic and trauma surgery. Objective: To validate the importance of tranexamic acid in elective and emergency surgery in orthopedics and traumatology. Discussion: Pubmed/Medline, SciELO, VHL, Scopus, Ebsco and Cochrane databases were reviewed, using the descriptors "tranexamic acid", "reduction of postoperative bleeding in orthopedics", "blood loss", "hemostatic agents", "transfusion risk" and "management of multiple trauma patients". Conclusions: Although some authors diverge regarding the adequate dose of tranexamic acid in orthopedics and traumatology, all conclude that this product controls bleeding in traumatic situations and in elective or emergency surgeries.

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Bisphenol A (BPA) is a micro-pollutant found in various environmental matrices at concentrations as low as ng/L. Recent studies have shown that this compound can cause oxidative damage and neurotoxic effects in aquatic organisms. However, there is a lack of research investigating the effects of BPA at environmentally relevant concentrations. Therefore, this study aimed to assess the neurotoxic effects of acute BPA exposure (96 h) at environmentally relevant concentrations (220, 1180, and 1500 ng/L) in adult zebrafish (Danio rerio). The Novel Tank trial was used to evaluate fish swimming behavior, and our results indicate that exposure to 1500 ng/L of BPA reduced the total distance traveled and increased freezing time. Furthermore, the evaluation of biomarkers in the zebrafish brain revealed that BPA exposure led to the production of reactive oxygen species and increased acetylcholinesterase activity. Gene expression analysis also indicated the overexpression of mbp, α1-tubulin, and manf in the zebrafish brain. Based on our findings, we concluded that environmentally relevant concentrations of BPA can cause anxiety-like behavior and neurotoxic effects in adult zebrafish.

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This study assessed the effects of Bisphenol A in embryonic stages of zebrafish, applying an IBR multi-biomarker approach that included alterations in growth and oxidative status and relates it with the expression of Nrf1, Nrf2, Wnt3a, Wnt8a, COX-2, Qdpra, and DKK1 genes. For this purpose, we exposed zebrafish embryos to eight environmentally relevant concentrations of BPA (220, 380, 540, 700, 860, 1180, 1340, and 1500 ng L-1) until 96 h post-fertilization. Our results show that BPA induces several malformations in embryos (developmental delay, hypopigmentation, tail malformations, and on), leading to their death. The LC50, EC50 of malformations, and teratogenic index (TI) were 1234.60 ng L-1, 987.77 ng L-1, and 1.25, respectively; thus, this emerging contaminant is teratogenic. Regarding oxidative stress and gene expression, we demonstrated BPA altered oxidative status and the gene expression in embryos of Danio rerio.

Assuntos

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Several studies have reported the presence of phenytoin (PHE) in wastewater treatment plant effluents, hospital effluents, surface water, and even drinking water. However, published studies on the toxic effects of PHE at environmentally relevant concentrations in aquatic organisms are scarce. The present study aimed to determine the effect of three environmentally relevant concentrations of PHE (25, 282, and 1500 ng L-1) on behavioral parameters using the novel tank test. Moreover, we also aimed to determine whether or not these concentrations of PHE may impair acetylcholinesterase (AChE) activity and oxidative status in the brain of Danio rerio adults. Behavioral responses suggested an anxiolytic effect in PHE-exposed organisms, mainly observed in organisms exposed to 1500 ng L-1, with a significant decrease in fish mobility and a significant increase in activity at the top of the tank. Besides the behavioral impairment, PHE-exposed fish also showed a significant increase in the levels of lipid peroxidation, hydroperoxides, and protein carbonyl content compared to the control group. Moreover, a significant increase in brain AChE levels was observed in fish exposed to 282 and 1500 ng L-1. The results obtained in the present study show that PHE triggers a harmful response in the brain of fish, which in turn generates fish have an anxiety-like behavior.

Assuntos

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Fluoxetine (FLX) exerts its therapeutic effect by inhibiting the presynaptic reuptake of the neurotransmitter serotonin. Nonetheless, at high concentrations of this drug, adverse effects occur in the brain of exposed organisms. Bearing this into account, the objective of this study was to evaluate the neurotoxic effects of the fluoxetine through the evaluation of behavior (Novel tank test), determination of oxidative stress, and determination of acetylcholinesterase (AChE) activity in adult zebrafish Danio rerio. For this purpose, Danio rerio adults were exposed to three environmentally relevant concentrations (5, 10, 16 ng L-1) of FLX for 96 h. Our results demonstrate fish presented a significant disruption in their behavior, as they remained long-lasting time frozen at the top of the tank. Since we observed a significant reduction of AChE activity in the brain of fish, we believe the above described anxiety-like state is the result of this enzyme impairment. Moreover, as FLX-exposed fish showed a significant increase in the levels of oxidative damage biomarkers, we suggest this AChE disruption is associated with the oxidative stress response fish exhibited. Based on our findings, we believe the environmentally relevant concentration of FLX alters the redox status of the brain, impairing this way the behavior of fish and making them more vulnerable to predation.

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