cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14278991.v1
title: SENSING PHASE OF POLY(VINYL CHLORIDE) IN THE DETECTION OF 17β-ESTRADIOL IN WATER ENVIRONMENT USING MID-INFRARED SPECTROSCOPY AND CHEMOMETRICS

description: In recent years, estrogens have gained notable attention among emerging pollutants, increasingly leading to the need for less laborious analytical methods. Optical sensors are a promising technology for the determination of chemical contaminants in water, acting as an alternative screening method. The aim of this work was to evaluate the performance of poly(vinyl chloride) (PVC) as a sensing phase for the detection of 17β-estradiol in water using mid-infrared spectroscopy and chemometrics. The sensing phase was used for differentiation purposes with an accuracy of 80%, sensitivity of 100% and specificity of 71.4% based on soft independent modeling of class analogy (SIMCA). Satisfactory limits of detection (8.9x10-1 - 2.9 mg L-1), quantification (2.9 - 1.0x10 mg L-1), slope of the analytical curve (5.0x10-4 - 2.4x10-3 L mg-1) and determination coefficients (0.90 - 0.99) were obtained. Kinetically, a extraction time of around 30 min was estimated and in a regeneration study, it was possible to use the same phase after 4 cycles of use. Therefore, the results indicate that the PVC sensing phase is promising for the detection of 17β-estradiol in water by means of mid-infrared spectroscopy and chemometric methods.
DOI: 10.6084/m9.figshare.14278993.v1
title: DETERMINATION OF THE PESTICIDES IN WATER USED IN THE CULTURE AND PROCESSING OF POTATOES

description: The contamination of water bodies by pesticide residues through direct flow, leaching and other methods has motivated the development of analytical methods for the determination of these compounds in water. A vortex-assisted liquid-liquid microextraction method followed by gas chromatography coupled to mass spectrometry for the determination of anilazine, linuron, prothiofos, and tebuconazole residues in water samples from the culture and processing of potatoes (Solanum tuberosum L.) was optimized. The complete factorial design and the central rotational compound design combined with the desirability function were used to evaluate and optimize the parameters of the method. The optimized conditions for extracting the pesticides were as follows: 316 µL of toluene, no sodium chloride addition, and a stirring time of 187 s. The method presented an enrichment factor of 142.4 times and good linearity, precision and accuracy, with limits of detection (LOD) of 0.005 - 0.007 mg L-1 and limits of quantification (LOQ) of 0.016 - 0.022 mg L-1. The co-extractives of the wastewater samples caused the suppression of the chromatographic response of linuron and prothiofos by 7.82 and 27.63%, respectively. The analyte concentrations in the wastewater samples from the industrial shing process, manual potato washing, and dam water were either lower than the LODs of the method or were absent.
DOI: 10.6084/m9.figshare.14278997
title: ASSESSMENT OF FUNCTIONALIZED CARBON NANOTUBES AIMING AT THE DEVELOPMENT OF PRECONCENTRATION METHODS OF METALLIC IONS AND DETERMINATION BY SPECTROMETRIC AND ELECTROANALYTICAL TECHNIQUES

description: This review focuses on the use of functionalized carbon nanotubes (CNTs) on the development of preconcentration methods with substantial contributions on selectivity and sensitivity for metal ions determination. CNTs have been usually employed in the development of preconcentration/speciation coupled to spectroanalytical techniques for ions determination at trace levels in different kind of samples. With regard the electroanalytical ones, this material has been widely used in adsorptive voltammetry procedures. Despite intrinsic features of CNTs, they suffer from poor dispersion in aqueous medium and wettability, thus making them very useful for sorption of hydrophobic metallic complex, but few indicated for metallic ions. Thus, different syntheses strategies, purification and chemical and physical approaches for surface functionalization/modification have been reported for improving the applicability of CNTs for a wide range of analytes. Therefore, apart from the brief description of the main physical and chemical characteristics of the carbon nanotubes, this review report the critical evaluation of main applications of modified CNTs as solid phase and as electrodic material for metal ions determination in environmental samples, food and biological using spectroanalytical techniques such as flame and graphite furnace atomic absorption spectrometry and inductively coupled plasma atomic emission spectrometry and electroanalytical mainly the adsorptive voltammetric ones.
DOI: 10.6084/m9.figshare.14278994
title: ON THE HYDROGEN EVOLUTION MECHANISM DURING CORROSION OF THE 2198-T8 ALLOY IN CHLORIDE SOLUTION: AN ELECTROCHEMICAL APPROACH

description: Corrosion is still one of the most serious and frequent problems in industries. The phenomena involved in the corrosion mechanism of Al-alloys may be explained by formation of galvanic cells between the metal matrix and heterogeneities, such as precipitates, intermetallic phases leading to potential differences and electrochemical reactions. In the cathodic sites, the main reactions are oxygen reduction reaction, in aerated neutral environments, and hydrogen evolution in acid media. This last type of reaction might also occur in neutral solutions inside pits (anodic region). In this study, the mechanism of hydrogen evolution during corrosion of the 2198-T8 Al-Cu-Li alloy exposed in a chloride solution was investigated. The mechanism was related to the presence of T1 phase (Al2CuLi), which is the main strengthening phase in this material. This phase is highly active and, when exposed to corrosive media, leads to severe localized corrosion (SLC). One of the main characteristics related to SLC is hydrogen gas evolution which was confirmed by gel visualization. In this study, the hydrogen evolution mechanism inside the SLC sites was studied by scanning electrochemical microscopy (SECM).
DOI: 10.6084/m9.figshare.14278995.v1
title: GOLD CHEMOTHERAPEUTIC COMPOUNDS: AN OVERVIEW OF ANTICANCER Au(I/III)-COMPLEXES IN RELATION TO THE STRUCTURE OF THE LIGAND

description: Gold compounds engage an important place in the field of medicinal chemistry due to their therapeutic properties. Since the last four decades, Au(I) and Au(III) complexes have attracted the attention of researchers due to their anti-tumor proprieties and the different mechanisms of action they display in comparison to conventional anticancer platinum compounds. Au(I/III) complexes can inhibit the activity of enzymes containing thiols including thioredoxin reductase; nevertheless, the affinity for several therapeutic targets has been confirmed in recent years. The properties conferred by auxiliary ligands such as phosphines (PR3) and N-heterocyclic carbenes (NHCs) to gold complexes have been key to the development of more promising anticancer compounds. In the same way, it has happened with the inclusion of some multidentate ligands in Au(III) complexes, increasing their stability and selectivity for tumor cells. In this review, we discuss the anticancer effects of Au(I) complexes containing PR3 and NHCs ligands as well as Au(III) complexes containing multidentate ligands especially those that have high cytotoxicity and information on the mechanism of action, as well as attempts to target identification and validation.
DOI: 10.6084/m9.figshare.14278997.v1
title: ASSESSMENT OF FUNCTIONALIZED CARBON NANOTUBES AIMING AT THE DEVELOPMENT OF PRECONCENTRATION METHODS OF METALLIC IONS AND DETERMINATION BY SPECTROMETRIC AND ELECTROANALYTICAL TECHNIQUES

description: This review focuses on the use of functionalized carbon nanotubes (CNTs) on the development of preconcentration methods with substantial contributions on selectivity and sensitivity for metal ions determination. CNTs have been usually employed in the development of preconcentration/speciation coupled to spectroanalytical techniques for ions determination at trace levels in different kind of samples. With regard the electroanalytical ones, this material has been widely used in adsorptive voltammetry procedures. Despite intrinsic features of CNTs, they suffer from poor dispersion in aqueous medium and wettability, thus making them very useful for sorption of hydrophobic metallic complex, but few indicated for metallic ions. Thus, different syntheses strategies, purification and chemical and physical approaches for surface functionalization/modification have been reported for improving the applicability of CNTs for a wide range of analytes. Therefore, apart from the brief description of the main physical and chemical characteristics of the carbon nanotubes, this review report the critical evaluation of main applications of modified CNTs as solid phase and as electrodic material for metal ions determination in environmental samples, food and biological using spectroanalytical techniques such as flame and graphite furnace atomic absorption spectrometry and inductively coupled plasma atomic emission spectrometry and electroanalytical mainly the adsorptive voltammetric ones.
DOI: 10.6084/m9.figshare.14278994.v1
title: ON THE HYDROGEN EVOLUTION MECHANISM DURING CORROSION OF THE 2198-T8 ALLOY IN CHLORIDE SOLUTION: AN ELECTROCHEMICAL APPROACH

description: Corrosion is still one of the most serious and frequent problems in industries. The phenomena involved in the corrosion mechanism of Al-alloys may be explained by formation of galvanic cells between the metal matrix and heterogeneities, such as precipitates, intermetallic phases leading to potential differences and electrochemical reactions. In the cathodic sites, the main reactions are oxygen reduction reaction, in aerated neutral environments, and hydrogen evolution in acid media. This last type of reaction might also occur in neutral solutions inside pits (anodic region). In this study, the mechanism of hydrogen evolution during corrosion of the 2198-T8 Al-Cu-Li alloy exposed in a chloride solution was investigated. The mechanism was related to the presence of T1 phase (Al2CuLi), which is the main strengthening phase in this material. This phase is highly active and, when exposed to corrosive media, leads to severe localized corrosion (SLC). One of the main characteristics related to SLC is hydrogen gas evolution which was confirmed by gel visualization. In this study, the hydrogen evolution mechanism inside the SLC sites was studied by scanning electrochemical microscopy (SECM).
DOI: 10.6084/m9.figshare.14278999
title: CONSTITUENTS FROM ROOTS OF Maytenus distichophylla, ANTIMICROBIAL ACTIVITY AND TOXICITY FOR CELLS AND Caenorhabditis elegans

description: Maytenus distichophylla is a medicinal species used in Northeast of Brazil. The hexane (HE), chloroform (CE), ethyl acetate (EAE) and methanol (ME) extracts and compounds from its roots were evaluated for their protective activity against Staphylococcus aureus and Candida albicans. The cytotoxicity for chronic myeloid leukemia (K562), acute monocytic leukemia (THP-1), and peripheral blood mononuclear cells of normal individuals (PBMC) cells was established by MTT method using etoposide as standard. The in vivo toxicity of samples was determined using Caenorhabditis elegans model. From HE and CE were isolated: friedelan-3-one (1), b-sitosterol (2), 3-oxo-olean-9(11),12-diene (3), a mixture of pristimerin (4) and 11a-hydroxylup-20(29)-en-3-one (5), 30-hydroxylup-20(29)-en-3-one (6), friedelane-3,7-dione (7), tingenone (8) and triacylglycerol (9). The structures of 1-9 were confirmed by spectral data. All samples reduced the viability of S. aureus and present no effect against C. albicans. The HE, CE, mixture of 4/5 and 8 reduced 75% of S. aureus viability. Cytotoxic effect for K562 and THP-1 cells was caused by compounds 1, 2 and 8. All samples displayed selectivity for leukemic cells and low toxicity to PBMC cells, suggesting their potential as anticancer agents. Extracts and compounds were non-toxic to L1 larvae of C. elegans. However, most of them reduced significantly young adult worm’s survival, being considered as potential nematicides.
DOI: 10.6084/m9.figshare.10063058
title: Dataset on the effect of vancomycin on metabolic changes in type 1 diabetic mice

description: Here we treated streptozotocin-induced diabetic mice with vancomycin (Vanc) to disturb the gut microbiota and host metabolic phenotype. In order to study the effect of vancomycin on host metabolism, a <sup>1</sup>H NMR-based metabolomics approach was applied to analyze metabolic changes in caecum contents, feces, caecum tissues, colonic tissues, serum, and hippocampus of normal control (CON), type 1 diabetic (T1D), and vancomycin-treated type 1 diabetic (T1DV) mice at 3, 7 and 11 weeks.<br> This study is submitted to Microbiome. Hong Zheng, Pengtao Xu, Qiaoying Jiang, Qingqing Xu, Yafei Zheng, Junjie Yan, Hui Ji, Jie Ning<sup>1</sup>, Xi Zhang, Chen Li, Limin Zhang, Yuping Li, Xiaokui Li, Weihong Song, and Hongchang Gao. (2021). Depletion of acetate-producing bacteria from the gut microbiota facilitates cognitive impairment through the gut-brain neural mechanism in diabetic mice.
DOI: 10.6084/m9.figshare.14278995
title: GOLD CHEMOTHERAPEUTIC COMPOUNDS: AN OVERVIEW OF ANTICANCER Au(I/III)-COMPLEXES IN RELATION TO THE STRUCTURE OF THE LIGAND

description: Gold compounds engage an important place in the field of medicinal chemistry due to their therapeutic properties. Since the last four decades, Au(I) and Au(III) complexes have attracted the attention of researchers due to their anti-tumor proprieties and the different mechanisms of action they display in comparison to conventional anticancer platinum compounds. Au(I/III) complexes can inhibit the activity of enzymes containing thiols including thioredoxin reductase; nevertheless, the affinity for several therapeutic targets has been confirmed in recent years. The properties conferred by auxiliary ligands such as phosphines (PR3) and N-heterocyclic carbenes (NHCs) to gold complexes have been key to the development of more promising anticancer compounds. In the same way, it has happened with the inclusion of some multidentate ligands in Au(III) complexes, increasing their stability and selectivity for tumor cells. In this review, we discuss the anticancer effects of Au(I) complexes containing PR3 and NHCs ligands as well as Au(III) complexes containing multidentate ligands especially those that have high cytotoxicity and information on the mechanism of action, as well as attempts to target identification and validation.
DOI: 10.6084/m9.figshare.14278999.v1
title: CONSTITUENTS FROM ROOTS OF Maytenus distichophylla, ANTIMICROBIAL ACTIVITY AND TOXICITY FOR CELLS AND Caenorhabditis elegans

description: Maytenus distichophylla is a medicinal species used in Northeast of Brazil. The hexane (HE), chloroform (CE), ethyl acetate (EAE) and methanol (ME) extracts and compounds from its roots were evaluated for their protective activity against Staphylococcus aureus and Candida albicans. The cytotoxicity for chronic myeloid leukemia (K562), acute monocytic leukemia (THP-1), and peripheral blood mononuclear cells of normal individuals (PBMC) cells was established by MTT method using etoposide as standard. The in vivo toxicity of samples was determined using Caenorhabditis elegans model. From HE and CE were isolated: friedelan-3-one (1), b-sitosterol (2), 3-oxo-olean-9(11),12-diene (3), a mixture of pristimerin (4) and 11a-hydroxylup-20(29)-en-3-one (5), 30-hydroxylup-20(29)-en-3-one (6), friedelane-3,7-dione (7), tingenone (8) and triacylglycerol (9). The structures of 1-9 were confirmed by spectral data. All samples reduced the viability of S. aureus and present no effect against C. albicans. The HE, CE, mixture of 4/5 and 8 reduced 75% of S. aureus viability. Cytotoxic effect for K562 and THP-1 cells was caused by compounds 1, 2 and 8. All samples displayed selectivity for leukemic cells and low toxicity to PBMC cells, suggesting their potential as anticancer agents. Extracts and compounds were non-toxic to L1 larvae of C. elegans. However, most of them reduced significantly young adult worm’s survival, being considered as potential nematicides.
DOI: 10.6084/m9.figshare.14279005
title: COMPARISON OF METHODS FOR DETERMINATION OF HUMIC SUBSTANCES IN COMMERCIAL LIQUID FERTILIZERS

description: The beneficial effects of humic substances (HS) on crop development have been evidenced in the last decade, leading to the commercialization of HS products with fertilizing properties. Currently, three methods are frequently used for HS determination: method described in the manual of the Brazilian Ministry of Agriculture, Livestock and Supply (MAPA); method employed by the United States Humic Products Trade Association (HPTA) and method used for the determination of soil HS (“HS-Soil”). This study aimed to evaluate and compare the quantification of HS in commercial liquid fertilizers, by the mentioned methods. For HA-rich fertilizers the studied methodologies presented results close to the HA and FA contents informed in the labels. For products rich in FA, the methodologies that use dichromate to oxidize organic carbon overestimated the results of FA, taking as reference the HPTA method, that determines gravimetrically the purified FA and HA. The time of analysis varied between the methodologies studied, as well as the type and volume of the produced waste. Based on the chemical principle of HS determination of the method and the environmental impact of the waste generated, we propose that the most appropriate method for determination of HS in liquid fertilizers is that of HPTA.
DOI: 10.6084/m9.figshare.14279007
title: ELABORATION AND USE OF ANIMATION AS STRATEGY TO TEACHING ORGANIC REACTIONS MECHANISM

description: The Chemistry of organic compounds is present in many aspects of life on the planet. In addition to many substances in our body being organic compounds, the energy matrix is based on burning fossil fuels, the biodiesel industry is also linked to organic reactions as well as the pharmaceutical industry. However, Organic Reaction Mechanisms is considered one of the most difficult subjects of undergraduate courses in chemistry. In order to improve the teaching-learning process, it was planned to elaborate animations on mechanisms of organic reactions, using simple programs accessible to all operating systems. Better than two-dimensional representation, the three-dimensional animations represent more concretely a model, at a macroscopic level, of what occurs on a sub-atomic scale. This is a new initiative to motivate students to study the concepts related to the subject of Mechanisms in Organic Chemistry, through research, planning and elaboration of animations. As a result, videos of the main reactions worked out in chemistry undergraduate courses were made, making the study of Organic Reactions more enlightening and understandable and demonstrated the use of computational technologies in the teaching of Organic Chemistry. It is an innovative, accessible, motivating and applicable teaching strategy in chemical courses.
DOI: 10.6084/m9.figshare.14279002
title: SYNERGISMS BETWEEN METAL AND PHOTOREDOX CATALYSIS: DECONVOLUTING COMPLEX SYSTEMS

description: This review briefly describes the evolution of organometallic chemistry and photoredox catalysis as independent fields; followed by a more in-depth presentation and discussion of representative examples derived from their synergistic combination, which generally leads to powerful cross-coupling protocols. In this context, the rational deconvolution of these complex catalytic systems into their isolated, more simple components are evaluated in order to understand their properties and reactivities.
DOI: 10.6084/m9.figshare.14279007.v1
title: ELABORATION AND USE OF ANIMATION AS STRATEGY TO TEACHING ORGANIC REACTIONS MECHANISM

description: The Chemistry of organic compounds is present in many aspects of life on the planet. In addition to many substances in our body being organic compounds, the energy matrix is based on burning fossil fuels, the biodiesel industry is also linked to organic reactions as well as the pharmaceutical industry. However, Organic Reaction Mechanisms is considered one of the most difficult subjects of undergraduate courses in chemistry. In order to improve the teaching-learning process, it was planned to elaborate animations on mechanisms of organic reactions, using simple programs accessible to all operating systems. Better than two-dimensional representation, the three-dimensional animations represent more concretely a model, at a macroscopic level, of what occurs on a sub-atomic scale. This is a new initiative to motivate students to study the concepts related to the subject of Mechanisms in Organic Chemistry, through research, planning and elaboration of animations. As a result, videos of the main reactions worked out in chemistry undergraduate courses were made, making the study of Organic Reactions more enlightening and understandable and demonstrated the use of computational technologies in the teaching of Organic Chemistry. It is an innovative, accessible, motivating and applicable teaching strategy in chemical courses.
DOI: 10.6084/m9.figshare.14279002.v1
title: SYNERGISMS BETWEEN METAL AND PHOTOREDOX CATALYSIS: DECONVOLUTING COMPLEX SYSTEMS

description: This review briefly describes the evolution of organometallic chemistry and photoredox catalysis as independent fields; followed by a more in-depth presentation and discussion of representative examples derived from their synergistic combination, which generally leads to powerful cross-coupling protocols. In this context, the rational deconvolution of these complex catalytic systems into their isolated, more simple components are evaluated in order to understand their properties and reactivities.
DOI: 10.6084/m9.figshare.14279005.v1
title: COMPARISON OF METHODS FOR DETERMINATION OF HUMIC SUBSTANCES IN COMMERCIAL LIQUID FERTILIZERS

description: The beneficial effects of humic substances (HS) on crop development have been evidenced in the last decade, leading to the commercialization of HS products with fertilizing properties. Currently, three methods are frequently used for HS determination: method described in the manual of the Brazilian Ministry of Agriculture, Livestock and Supply (MAPA); method employed by the United States Humic Products Trade Association (HPTA) and method used for the determination of soil HS (“HS-Soil”). This study aimed to evaluate and compare the quantification of HS in commercial liquid fertilizers, by the mentioned methods. For HA-rich fertilizers the studied methodologies presented results close to the HA and FA contents informed in the labels. For products rich in FA, the methodologies that use dichromate to oxidize organic carbon overestimated the results of FA, taking as reference the HPTA method, that determines gravimetrically the purified FA and HA. The time of analysis varied between the methodologies studied, as well as the type and volume of the produced waste. Based on the chemical principle of HS determination of the method and the environmental impact of the waste generated, we propose that the most appropriate method for determination of HS in liquid fertilizers is that of HPTA.