Publications by authors named "Helvecio Costa Menezes"

Jabuticaba (Plinia cauliflora) is a typical subtropical Brazilian fruit with unique organoleptic properties and a high nutritional value. This study shows a qualitative analysis of jabuticaba peels with volatile and semi-volatile components harvested from Minas Gerais, Brazil. A new device, the hydrophilic microporous cartridge, was developed to extract jabuticaba peels' volatile/semi-volatile components using a solid-phase microextraction method by direct immersion.

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Contamination by polycyclic aromatic hydrocarbons (PAHs) is an urgent environmental concern, given its atmospheric dispersion and deposition in water bodies and soils. These compounds and their nitrated and oxygenated derivatives, which can exhibit high toxicities, are prioritized in environmental analysis contexts. Amid the demand for precise analytical techniques, comprehensive two-dimensional chromatography coupled with mass spectrometry (GCxGC/Q-TOFMS) has emerged as a promising tool, especially in the face of challenges like co-elution.

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Bisphenol A (BPA) is an endocrine-disrupting chemical with a potential role in endocrine cancers. However, the effects of BPA on the salivary glands have been barely explored. We investigated the impact of in vivo sub-chronic exposure to BPA and its in vitro effects on human salivary gland mucoepidermoid carcinoma cell lines.

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Among the main approaches for predicting the spatial positions of eluates in comprehensive two-dimensional gas chromatography, the still under-explored computational models based on deep learning algorithms emerge as robust and reliable options due to their high adaptability to the structure and complexity of the data. In this work, an open-source program based on deep neural networks was developed to optimize chromatographic methods and simulate operating conditions outside the laboratory. The deep neural networks models were fit to convenient experimental predictors, resulting in scaled losses (mean squared error) equivalent to 0.

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Background: To evaluate the release of bisphenol-A glycidyl methacrylate (BisGMA), triethylene glycol dimethacrylate (TEGDMA), bisphenol A (BPA), and phthalates of the composite resin used in the bonding of spurs applied in the treatment of children with anterior open bite and its effects on human keratinocytes.

Methodology: Saliva samples of 22 children were collected before spur attachment (baseline) and 30 minutes (min) and 24 hours (h) after spur bonding. Analysis was performed using high-performance liquid chromatography (HPLC) coupled to tandem mass spectrometry (HPLC-MS/MS) and gas chromatography coupled to mass spectrometry (GC-MS).

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Several endophytic fungi have been reported to have produced bioactive metabolites. Some of them, including the Induratia species, have the capacity to emit volatile compounds with antimicrobial properties with broad spectrum against human and plant pathogens. The present study aimed to prospect the Induratia species producing volatile organic compounds (VOCs), in carqueja plants used in alternative medicine and coffee plants in Brazil.

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A risk assessment and a source apportionment of the particulate- and gas-phase PAHs were conducted in a high vehicular traffic and industrialized region in southeastern Brazil. Higher concentrations of PAHs were found during summer, being likely driven by the contributions of PAHs in the vapor phase caused by fire outbreaks during this period. Isomer ratio diagnostic and Principal Component Analysis (PCA) identified four potential sources in the region, in which the Positive Matrix Factorization (PMF) model confirmed and apportioned as gasoline-related (31.

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Bisphenol A (BPA) is an endocrine disrupting chemical able to promote hormone-responsive tumors. The major route of BPA contamination being oral, the aim of the present study was to investigate BPA effects on oral cells. Here, we evaluated the impact of sub-chronic in vivo exposure to BPA and its in vitro effects on neoplastic and non-neoplastic oral cells.

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Bisphenol A and phthalates are endocrine disruptors widely used as chemical additives mainly in plastic products, including materials for dentistry procedures. Besides, many plasticizers have been associated with important diseases requiring performed methods for their quantification. In the present study, an alternative method for the determination of bisphenol A (BPA) and phthalate metabolites in saliva was developed and validated using hollow fiber liquid phase microextraction (HF-LPME) for sample preparation and gas chromatography coupled to ion trap mass spectrometry (GC/MS) for analysis.

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Air quality in large cities has worsened in recent years as a consequence people's health is directly affected. Among the toxic compounds released to environmental air are polycyclic aromatic hydrocarbons (PAHs), nitrated PAHs (nitro-PAHs), and oxygenated PAHs (oxy-PAHs). Performant methods to analyze these compounds is necessary to enable adequate monitoring of air quality.

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Polycyclic aromatic hydrocarbons (PAHs) are food contaminants; besides, their oxygenated (oxy-PAHs) and nitrated (nitro-PAHs) derivatives have also been detected in some foods. This is worrying because these derivatives may be more toxic than PAHs. This study presents a new method for the determination of PAHs and their oxygenated and nitrated derivatives in coffee brew.

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Aim: The increasing use of cocaine (COC) during breastfeeding has led to growing concern about exposure of infants. Therefore, to study this exposure, a new method to analyze COC and benzoylecgonine in breast milk was developed.

Methodology: A new extraction method was used for the first time to analyze COC and its major metabolite, benzoylecgonine, in breast milk using magnetic carbon nanotubes partially doped with nitrogen.

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This article describes a simple, efficient, and versatile magnetic carbon nanotubes (MCNT) method for sampling and pre-concentration of pesticides in environmental water samples. The multi-walled magnetic carbon nanotubes were obtained by chemical deposition vapor (CVD) process. The MCNTs structures are formed of hydrophobic and hydrophilic fractions that provide great dispersion at any water matrix allowing simultaneously a high efficiency of pesticides sorption.

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This paper describes a new, efficient and versatile method for the sampling and preconcentration of PAH in environmental water matrices using special hybrid magnetic carbon nanotubes. These N-doped amphiphilic CNT can be easily dispersed in any aqueous matrix due to the N containing hydrophilic part and at the same time show high efficiency for the adsorption of different PAH contaminants due to the very hydrophobic surface. After adsorption, the CNT can be easily removed from the medium by a simple magnetic separation.

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Bile acids (BAs) are derived from cholesterol and produced in the liver. The most abundant bile acids in humans are usually conjugated with glycine and taurine and are divided into primary BAs such as cholic acid (CA) and chenodeoxycholic acid (CDCA) and secondary BAs like deoxycholic acid (DCA), lithocholic acid (LCA) and ursodeoxycholic acid (UDCA). The differences amongst individual bile acids (BAs) are significant in order to distinguish different pathological processes and exposure to chemical compounds.

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Metabolome analysis involves the study of small molecules that are involved in the metabolic responses that occur through patho-physiological changes caused by genetic stimuli or chemical agents. Qualitative and quantitative metabolome analyses are used for the diagnosis of various diseases or chemical exposure. This article presents an overview of the different analytical methods available for performing the determination of the metabolome, including sampling, sample preparation and processing and interpretation of data.

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The analysis of amino acid levels is crucial for neuroscience studies because of the roles of these molecules as neurotransmitters and their influence on behavior. The present study describes the distribution and levels of 16 amino acids (alanine, asparagine, aspartic acid, cysteine, glycine, glutamic acid, isoleucine, leucine, lysine, methionine, phenylalanine, proline, sarcosine, serine, valine, and threonine) in brain tissues (prefrontal cortex, striatum, hippocampus and cerebellum) and the serum. Neurochemical analysis was performed on Wistar rats and C57BL/6 mice using an efficient method for extraction, a fast microwave-assisted derivatization and gas chromatography-mass spectrometry analysis.

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The determination of the concentrations of l-amino acids in cerebrospinal fluid (CSF) has been used to gain biochemical insight into central nervous system disorders. This paper describes a microwave-assisted derivatization (MAD) method using N,O-bis-(trimethylsilyl)trifluoroacetamide (BSTFA) as a derivatizing agent for determining the concentrations of l-amino acids in human CSF by gas chromatography with mass spectrometry (GC/MS). The experimental design used to optimize the conditions showed that the optimal derivatization time was 3min with a microwave power of 210W.

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Polycyclic aromatic hydrocarbons (PAH) from ambient air particulate matter (PM) were analyzed by a new method that utilized direct immersion (DI) and cold fiber (CF) SPME-GC/MS. Experimental design was used to optimize the conditions of extraction by DI-CF-SPME with a 100μm polydimethylsiloxane (PDMS) fiber. The optimal conditions included a 5min equilibration at 70°C time in an ultrasonic bath with an extraction time of 60min.

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