Laboratório Nacional de Ciência e Tecnologia do Bioetanol

This study describes the use of microchip micellar electrokinetic chromatography (MEKC) integrated with capacitively coupled contactless conductivity detection (C4D) for the determination of monoethylene glycol (MEG) in gas condensate samples. The samples were subjected to a liquid-liquid extraction step and then analyzed by chip-based MEKC-C4D. For this purpose, sodium dodecyl sulfate (SDS) was used as a surfactant at a concentration of 30mmol L-1 added in 50mmol L-1 phosphate (pH = 9.0). Samples were introduced into microchannels through floating injection mode by applying a voltage of 600V during 10 s. Separations were performed under an electric field of 82V cm-1 and monitored by C4D measurements recorded applying a 1200-kHz frequency sinusoidal wave with 20-Vpp excitation voltage. The proposed methodology employing MEKC-C4D revealed a linear behavior (r2 ≥ 0.99) in the MEG concentration range between 150-450µmol L-1 and LOD equal to 33µmol L-1. Three gas condensate samples were then analyzed, and the achieved MEG concentration values ranged from 173 to 213µmol L-1. Recovery experiments provided values between 89 and 102%. Based on the results reported in this study, MEKC-C4D devices have demonstrated to be a promising and ecological analytical tool for MEG analysis with huge potential for in-field applications.

O artigo parafraseia os trabalhos de Max Planck (1901) sobre a quantização da energia, de Albert Einstein (1905) em que propõe o quantum de luz, de Niels Bohr (1913) sobre a teoria atômica e de Louis de Broglie (1924) a respeito da dualidade onda-partícula. Esses trabalhos foram decisivos para a criação da mecânica quântica. O objetivo é comemorar o centenário do nascimento da física quântica e disponibilizar ao professor de física um material didático que considera episódios relevantes da história da física no início do século XX.

Background: Commiphora leptophloeos has long been used in Latin American folk medicine for the treatment of respiratory and gastrointestinal disorders. Therefore, toxicological and phytochemical investigations are required to assess the safety and support the evidence-based use of its bark in medicinal applications. This study aimed to evaluate the aqueous bark extract of C. leptophloeos, focusing on its chemical composition and its antioxidant, cytotoxic, and genotoxic properties. Methods: The aqueous extract was obtained by decoction of dried bark samples. Phytochemical characterization was conducted using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS), and data were processed using the NP3 MS Workflow 1.1.4 software, allowing for the annotation of key secondary metabolites. Antioxidant activity was assessed through multiple in vitro assays, including DPPH, ABTS, phosphomolybdenum, and reducing power tests. Cytotoxicity was evaluated using the MTT assay, while genotoxicity was investigated through the Ames test and micronucleus assay. Results: Phytochemical analysis revealed several flavonoids, with procyanidin B2 annotated as a major compound. The extract exhibited strong antioxidant activity, with EC50 values of 5.43 μg/mL (DPPH), 12.40 μg/mL (ABTS), 35.20 μg/mL (phosphomolybdenum), and 31.27 μg/mL (reducing power). The MTT assay showed no cytotoxic effects at concentrations up to 6400 μg/mL. Furthermore, both the Ames and micronucleus assays showed the absence of genotoxic effects at concentrations up to 1600 μg/plate and 400 μg/mL, respectively. Conclusions: The aqueous bark extract of C. leptophloeos demonstrates strong antioxidant potential and a favorable safety profile, with no detectable cytotoxicity or genotoxicity at concentrations effective in antioxidant assays. Further studies are recommended to confirm and validate its traditional medicinal properties using appropriate in vivo models, followed by pre-clinical evaluations.

This study aimed to identify splicing quantitative trait loci (cis-sQTL) in Nelore cattle muscle tissue and explore the involvement of spliced genes (sGenes) in immune system-related biological processes. Genotypic data from 80 intact male Nelore cattle were obtained using SNP-Chip technology, while RNA-Seq analysis was performed to measure gene expression levels, enabling the integration of genomic and transcriptomic datasets. The normalized expression levels of spliced transcripts were associated with single nucleotide polymorphisms (SNPs) through an analysis of variance using an additive linear model with the MatrixEQTL package. A permutation analysis then assessed the significance of the best SNPs for each spliced transcript. Functional enrichment analysis was performed on the sGenes to investigate their roles in the immune system. In total, 3,187 variants were linked to 3,202 spliced transcripts, with 83 sGenes involved in immune system processes. Of these, 31 sGenes were enriched for five transcription factors. Most cis-sQTL effects were found in intronic regions, with 27 sQTL variants associated with disease susceptibility and resistance in cattle. Key sGenes identified, such as GSDMA, NLRP6, CASP6, GZMA, CASP4, CASP1, TREM2, NLRP1, and NAIP, were related to inflammasome formation and pyroptosis. Additionally, genes like PIDD1, OPTN, NFKBIB, STAT1, TNIP3, and TREM2 were involved in regulating the NF-kB pathway. These findings lay the groundwork for breeding disease-resistant cattle and enhance our understanding of genetic mechanisms in immune responses.