cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14279032.v1
title: IMPROVING THE CATALYTIC FEATURES OF THE LIPASE FROM Rhizomucor miehei IMMOBILIZED ON CHITOSAN-BASED HYBRID MATRICES BY ALTERING THE CHEMICAL ACTIVATION CONDITIONS

description: The lipase from Rhizomucor miehei (RML) has been immobilized on chitosan-based hybrid (sodium alginate or carrageenan) matrices activated with glycidol (GLY), epichlorohydrin (EPI) or glutaraldehyde (GLU) groups. Then, the properties of the different biocatalysts have been evaluated and compared with the soluble RML. Thermal stability (at pH 7.0 and 60 °C) was significantly increased when compared to the soluble enzyme: 154-fold for chitosan 5.0% - GLU, 80-fold for chitosan 2.5% - carrageenan 2.5% - GLY and 93-fold for chitosan 2.5% - alginate 2.5% - EPI. The best biocatalyst preparation, which was 154-fold more stable than the soluble enzyme, was obtained when RML was immobilized on chitosan activated with glutaraldehyde 5.0% v/v. According to the results, it was concluded that RML immobilization on chitosan-based hybrid matrices using different chemistries greatly produced biocatalysts with different properties.
DOI: 10.6084/m9.figshare.14279034.v1
title: IN SITU DRIFTS/MS STUDIES ON THE INTERACTION OF METHANOL AND ETHYL ACETATE OVER MG-LA CATALYST

description: The surface intermediates formed on the Mg-La catalyst (molar ratio 1:1) were studied through temperature-programmed desorption (TPD) and diffuse reflectance infrared Fourier transform spectroscopy coupled to mass spectrometry (DRIFTS-MS) using methanol (MeOH) and ethyl acetate (EA) as probe molecules. TPD results showed that the products formed from adsorbed MeOH were hydrogen and formaldehyde, whereas EA produced hydrogen, ethanol, and acetone. DRIFTS-MS of a MeOH and EA mixture results showed that methanol adsorbs as methoxy species on the catalyst surface, and EA adsorbs through the oxygen of carbonyl groups forming ethoxy and acetate species. The reaction of the adsorbed intermediate species resulted in the formation of methane, CO2 gas phase, ethanol, and methyl acetate. Also, methanol adsorbed preferentially on the basic site and EA in a dissociative form. Surface intermediates identification allowed to confirm that the Eley-Rideal type mechanism was predominant on the catalyst surface studied.
DOI: 10.6084/m9.figshare.14279036
title: OPTIMIZATION OF THE NON-INVASIVE AND NON-DESTRUCTIVE EXTRACTION PROCESS AND ANALYSIS OF PAPAYA VOLATILE METABOLITES USING SPME-GC-MS

description: The analysis of volatiles is an alternative in the routine of quality control of fruits, since the volatile metabolites can change in the presence of microorganisms. A well-established method for extracting volatiles is the solid phase microextraction (SPME). This work aims to define some parameters (fiber coating, conditioning time and fiber exposure time) for an effective extraction. Whole papaya was inserted into a hermetically closed glass bottle and the system was left in conditioning for the volatiles accumulation. Then, extraction by SPME and subsequent desorption in a gas chromatograph was performed. Two fibers were evaluated: a 100 µm polydimethylsiloxane (PDMS) and a 65 µm polydimethylsiloxane/divinylbenzene (PDMS/DVB). The PDMS/DVB fiber extracted the highest number of volatiles. Central composite design (CCD) was performed to assess the effect of papaya conditioning time and the fiber exposure time on the response: number of detectable peaks. Both variables studied and their interactions were significant for the response. ANOVA showed that the quadratic terms and the lack of fit were not significant (p &lt;0.05). A conditioning time of 10 min and exposure time of 30 min was sufficient for the detection of more than 100 compounds.
DOI: 10.6084/m9.figshare.14279036.v1
title: OPTIMIZATION OF THE NON-INVASIVE AND NON-DESTRUCTIVE EXTRACTION PROCESS AND ANALYSIS OF PAPAYA VOLATILE METABOLITES USING SPME-GC-MS

description: The analysis of volatiles is an alternative in the routine of quality control of fruits, since the volatile metabolites can change in the presence of microorganisms. A well-established method for extracting volatiles is the solid phase microextraction (SPME). This work aims to define some parameters (fiber coating, conditioning time and fiber exposure time) for an effective extraction. Whole papaya was inserted into a hermetically closed glass bottle and the system was left in conditioning for the volatiles accumulation. Then, extraction by SPME and subsequent desorption in a gas chromatograph was performed. Two fibers were evaluated: a 100 µm polydimethylsiloxane (PDMS) and a 65 µm polydimethylsiloxane/divinylbenzene (PDMS/DVB). The PDMS/DVB fiber extracted the highest number of volatiles. Central composite design (CCD) was performed to assess the effect of papaya conditioning time and the fiber exposure time on the response: number of detectable peaks. Both variables studied and their interactions were significant for the response. ANOVA showed that the quadratic terms and the lack of fit were not significant (p &lt;0.05). A conditioning time of 10 min and exposure time of 30 min was sufficient for the detection of more than 100 compounds.
DOI: 10.6084/m9.figshare.14279039
title: ENRIQUECIMENTO ELEMENTAR POR MEIO DE CULTIVO: PLANTAS E COGUMELOS

description: The foods enrichment with essential elements is an alternative to supply deficiencies of micronutrients and the fortification by rich cultivation is a promising strategy for the elemental enrichment of agricultural origin products, mainly in regions where there is high prevalence. On the other hand, in elemental enrichment procedures, possible antagonistic and / or synergistic relationships in the absorption and translocation of essential elements in agricultural products should be evaluated. Additionally, it is important to highlight the need to know the elements species capable of being absorbed and used in the metabolism of edible plants and mushrooms as well as the species formed after enrichment, being necessary to evaluate mainly if enriched foods present the same chemical characteristics, when compared to those grown under natural conditions. Therefore, in this review, works from the literature are presented involving promising strategies for elemental enrichment of edible plants and mushrooms grown in an appropriate medium, prioritizing the chemical characterization of the enriched food. Cultivation enrichment procedures are an excellent and promising alternative to help reduce elemental deficiencies as well as to maintain the recommended daily intake of these essential micronutrients for human nutrition and health.
DOI: 10.6084/m9.figshare.14279035
title: HPLC METHOD IMPROVEMENT FOR 4-NONYLPHENOL DETERMINATION IN ANAEROBIC REACTORS: DECREASING SOLVENT CONSUMPTION AND WASTE GENERATION

description: The aim of this study was to develop a chromatographic method for 4-NP determination in anaerobic batch reactors using low amount of organic solvents and also evaluate 4-NP degradation in the presence of different co-substrates. Chromatographic parameters was improved for stationary phase (C-8 column), mobile phase (acetonitrile/water solution 90:10, v:v), column temperature (40 ºC), eluent flow (0.8 mL min-1), injection volume (100 µL) and wavelengths in fluorescence detector (FLD) (λex=225 nm and λem=305 nm). Solid phase extraction (SPE) was performed for sample purification with smaller amount of solvents (methanol - 2 mL and ethanol - 1 mL) than previously reported. Reduction in reagent consumption was about 5.5 times for HPLC and about 19 times for SPE, according to previously reported. Method was validated according to the linearity (0.9951), selectivity and limits of detection and quantification were 15.7 µg L-1 and 55.6 µg L-1, respectively. The 4-NP removal in anaerobic batch reactors was higher than 50% (4-NP initial concentration of 398 µg L-1). Fumarate was a better co-substrate to favor methanogenesis in the presence of 4-NP, which provided higher organic matter removal, higher methane production speed and shorter start-up time for methane production.
DOI: 10.6084/m9.figshare.14279035.v1
title: HPLC METHOD IMPROVEMENT FOR 4-NONYLPHENOL DETERMINATION IN ANAEROBIC REACTORS: DECREASING SOLVENT CONSUMPTION AND WASTE GENERATION

description: The aim of this study was to develop a chromatographic method for 4-NP determination in anaerobic batch reactors using low amount of organic solvents and also evaluate 4-NP degradation in the presence of different co-substrates. Chromatographic parameters was improved for stationary phase (C-8 column), mobile phase (acetonitrile/water solution 90:10, v:v), column temperature (40 ºC), eluent flow (0.8 mL min-1), injection volume (100 µL) and wavelengths in fluorescence detector (FLD) (λex=225 nm and λem=305 nm). Solid phase extraction (SPE) was performed for sample purification with smaller amount of solvents (methanol - 2 mL and ethanol - 1 mL) than previously reported. Reduction in reagent consumption was about 5.5 times for HPLC and about 19 times for SPE, according to previously reported. Method was validated according to the linearity (0.9951), selectivity and limits of detection and quantification were 15.7 µg L-1 and 55.6 µg L-1, respectively. The 4-NP removal in anaerobic batch reactors was higher than 50% (4-NP initial concentration of 398 µg L-1). Fumarate was a better co-substrate to favor methanogenesis in the presence of 4-NP, which provided higher organic matter removal, higher methane production speed and shorter start-up time for methane production.
DOI: 10.6084/m9.figshare.14279039.v1
title: ENRIQUECIMENTO ELEMENTAR POR MEIO DE CULTIVO: PLANTAS E COGUMELOS

description: The foods enrichment with essential elements is an alternative to supply deficiencies of micronutrients and the fortification by rich cultivation is a promising strategy for the elemental enrichment of agricultural origin products, mainly in regions where there is high prevalence. On the other hand, in elemental enrichment procedures, possible antagonistic and / or synergistic relationships in the absorption and translocation of essential elements in agricultural products should be evaluated. Additionally, it is important to highlight the need to know the elements species capable of being absorbed and used in the metabolism of edible plants and mushrooms as well as the species formed after enrichment, being necessary to evaluate mainly if enriched foods present the same chemical characteristics, when compared to those grown under natural conditions. Therefore, in this review, works from the literature are presented involving promising strategies for elemental enrichment of edible plants and mushrooms grown in an appropriate medium, prioritizing the chemical characterization of the enriched food. Cultivation enrichment procedures are an excellent and promising alternative to help reduce elemental deficiencies as well as to maintain the recommended daily intake of these essential micronutrients for human nutrition and health.
DOI: 10.6084/m9.figshare.14279041
title: QSAR STUDIES FOR SARS-CoV-2

description: The generation of mathematical models through the quantitative relationship between the chemical structure and the biological activity (QSARs) of compounds was used in this investigation. Mathematical models were generated from compounds available in literature that predicting the biological activity against SARS-CoV-2. The data indicate that the parameters that most interfere and allow to validate the equations are: number of hydrogen bonding donors, maximum projection radius and length perpendicular to the minimum area. This allows us to infer that there is synergism between the basic capacity of the cysteine protein action site present in the virus and the geometric conditions for the three-dimensional alignment to potential compounds with anti-SARS-CoV-2 action. The authors highlight that mathematical models assist in chemical research, but do not replace evaluation of the efficacy in vitro, in vivo, pre-clinical and clinical studies, which are essential for dosage, release or authorization to use any medication or supplement.
DOI: 10.6084/m9.figshare.14279041.v1
title: QSAR STUDIES FOR SARS-CoV-2

description: The generation of mathematical models through the quantitative relationship between the chemical structure and the biological activity (QSARs) of compounds was used in this investigation. Mathematical models were generated from compounds available in literature that predicting the biological activity against SARS-CoV-2. The data indicate that the parameters that most interfere and allow to validate the equations are: number of hydrogen bonding donors, maximum projection radius and length perpendicular to the minimum area. This allows us to infer that there is synergism between the basic capacity of the cysteine protein action site present in the virus and the geometric conditions for the three-dimensional alignment to potential compounds with anti-SARS-CoV-2 action. The authors highlight that mathematical models assist in chemical research, but do not replace evaluation of the efficacy in vitro, in vivo, pre-clinical and clinical studies, which are essential for dosage, release or authorization to use any medication or supplement.
DOI: 10.6084/m9.figshare.14279043
title: STRUCTURAL ASPECTS OF CHITOSAN/PVA SPHERES CROSS-LINKED WITH GLUTARALDEHYDE AND SUBMITTED TO DIFFERENT THERMAL TREATMENTS

description: Chitosan is a biopolymer derived from chitin and the most abundant polysaccharide in nature after cellulose. This biopolymer has been applied in different areas due its biodegradability and biocompatibility properties. Modifications of chitosan structure by cross-linking chemical agents can alter its physical, chemical, and morphological characteristics. The present work aimed at studying the structural characteristics of chitosan/polyvinyl alcohol (PVA) spheres cross-linked with glutaraldehyde submitted to oven-drying and freeze-drying processes. The thermal-treated of spheres and chitosan (control sample) were analyzed by XRD, SEM and FTIR techniques. Multivariate statistical analysis, PCA, was applied to samples IR spectra. According to results, the freeze-dried spheres showed a smaller crystal size (6.032 nm), while the oven-dried spheres presented a smaller crystalline phase (3.49%). MEV images have encompassed the different surfaces of the manufactured spheres as a result of drying methods. Slight chemical changes were observed in the IR spectra from the cross-linked spheres. In addition, PCA has revealed different clusters referred to the structural modifications. Therefore, the increasing of openness and receptivity for chemical reactions, as well as the adsorption capacity, could enable different applications of the chitosan, mainly the adsorption properties to remove residues and for water treatment.
DOI: 10.6084/m9.figshare.14279043.v1
title: STRUCTURAL ASPECTS OF CHITOSAN/PVA SPHERES CROSS-LINKED WITH GLUTARALDEHYDE AND SUBMITTED TO DIFFERENT THERMAL TREATMENTS

description: Chitosan is a biopolymer derived from chitin and the most abundant polysaccharide in nature after cellulose. This biopolymer has been applied in different areas due its biodegradability and biocompatibility properties. Modifications of chitosan structure by cross-linking chemical agents can alter its physical, chemical, and morphological characteristics. The present work aimed at studying the structural characteristics of chitosan/polyvinyl alcohol (PVA) spheres cross-linked with glutaraldehyde submitted to oven-drying and freeze-drying processes. The thermal-treated of spheres and chitosan (control sample) were analyzed by XRD, SEM and FTIR techniques. Multivariate statistical analysis, PCA, was applied to samples IR spectra. According to results, the freeze-dried spheres showed a smaller crystal size (6.032 nm), while the oven-dried spheres presented a smaller crystalline phase (3.49%). MEV images have encompassed the different surfaces of the manufactured spheres as a result of drying methods. Slight chemical changes were observed in the IR spectra from the cross-linked spheres. In addition, PCA has revealed different clusters referred to the structural modifications. Therefore, the increasing of openness and receptivity for chemical reactions, as well as the adsorption capacity, could enable different applications of the chitosan, mainly the adsorption properties to remove residues and for water treatment.
DOI: 10.6084/m9.figshare.14279045
title: WRITING STRATEGIES FOR INCORPORATING PUBLIC COMMUNICATION OF SCIENCE INTO CHEMISTRY EDUCATION

description: Although the impacts of science discoveries are relevant to society, awareness of this intellectual output is still minimal. Much of this communicative failure between researchers and the general public lies in the disclosure, which contributes to the superficiality and misinterpretations of the content served. Strategies need to be found to improve science communication worldwide, promoting well-grounded content and accessible language to a non-specialist audience. This work aims to report writing strategies used in a course about public communication of science, offered to undergraduate chemistry students. The results showed that students fully achieved the task of writing popular science texts as a science journalist, emphasizing their ease and difficulties throughout the activity.
DOI: 10.6084/m9.figshare.14279045.v1
title: WRITING STRATEGIES FOR INCORPORATING PUBLIC COMMUNICATION OF SCIENCE INTO CHEMISTRY EDUCATION

description: Although the impacts of science discoveries are relevant to society, awareness of this intellectual output is still minimal. Much of this communicative failure between researchers and the general public lies in the disclosure, which contributes to the superficiality and misinterpretations of the content served. Strategies need to be found to improve science communication worldwide, promoting well-grounded content and accessible language to a non-specialist audience. This work aims to report writing strategies used in a course about public communication of science, offered to undergraduate chemistry students. The results showed that students fully achieved the task of writing popular science texts as a science journalist, emphasizing their ease and difficulties throughout the activity.
DOI: 10.6084/m9.figshare.14279048
title: COLLOIDAL PEROVSKITE NANOCRYSTALS: HISTORY, PROPERTIES AND APPLICATI

description: Recently, a new class of materials, the Perovskite Nanocrystals, also known as perovskite quantum dots (PQDs) has emerged. Perovskite nanocrystals are promising in optoelectronics due to their quantum confinement properties, narrow photoluminescence bands with short decay times, optically tunable bandgaps, easy surface passivation and high photoluminescent quantum yields. The intense photoluminescence covering the entire visible region of the spectrum can be easily adjusted through the composition and/or the nanocrystals sizes. This paper presents the state-of-the-art of these materials, since their discovery to current research, including their synthesis methods, properties and applications.
DOI: 10.6084/m9.figshare.14279048.v1
title: COLLOIDAL PEROVSKITE NANOCRYSTALS: HISTORY, PROPERTIES AND APPLICATI

description: Recently, a new class of materials, the Perovskite Nanocrystals, also known as perovskite quantum dots (PQDs) has emerged. Perovskite nanocrystals are promising in optoelectronics due to their quantum confinement properties, narrow photoluminescence bands with short decay times, optically tunable bandgaps, easy surface passivation and high photoluminescent quantum yields. The intense photoluminescence covering the entire visible region of the spectrum can be easily adjusted through the composition and/or the nanocrystals sizes. This paper presents the state-of-the-art of these materials, since their discovery to current research, including their synthesis methods, properties and applications.
DOI: 10.6084/m9.figshare.14279053
title: LEARNING ABOUT EDGE EFFECTS AND ULTRAMICROELECTRODES IN ELECTROCHEMISTRY: SYNERGY BETWEEN EXPERIMENTS AND SIMULATIONS

description: A short experimental activity aimed at upper level undergraduate students or beginner researchers is presented to introduce the concepts of edge effects and hemispherical diffusion at ultramicroelectrodes. Students will perform simple cyclic voltammetry experiments varying the scan rate and using disk electrodes with different radii. They are then asked to interpret the results based on their previous knowledge. Simulations are also performed, which provide a clear visual interpretation of the underlying diffusion process and show the transition between linear and hemispherical diffusion regimes. The simulations are also presented as a tool to extend the study beyond the range of experimentally accessible conditions. The interplay between voltammetry experiments and simulations allows a natural comprehension of these concepts without the need of a previous rigorous theoretical introduction.
DOI: 10.6084/m9.figshare.14279051
title: VOLATILE COMPOUNDS IN CACHAÇAS OBTAINED FROM THREE SUGARCANE VARIETIES CULTIVATED UNDER THE MANAGEMENTS: ORGANIC, CONVENTIONAL AND WITHOUT FERTILIZATION

description: The volatile compounds present in cachaça can derive from the raw material used in the production of the beverage, from the fermentative process, from distillation or aging. The aim of the research was to evaluate the volatile compounds, in the cachaças from stills produced with different sugarcane varieties, under the organic and conventional managements. The varieties RB867515, RB962869 and RB85553 were cultivated in three distinct ways, planting without fertilization (OUTF); organic planting (ORGN) and conventional planting (CONV). The results showed that for the total esters, higher alcohols and coefficient of congeners present in the cachaça, the varieties and managements are dependent, unlike volatile acidity, total aldehydes, methyl alcohol and furfural. Therefore, the quality, origin and lineage of the sugarcane variety used for the production of cachaça were confirmed to influence the chemical concentrations of the volatile compounds of the beverage, modifying its chemical profile. It is worth reinforcing that none of the volatiles presented concentration above that allowed by the Brazilian legislation.
DOI: 10.6084/m9.figshare.14279053.v1
title: LEARNING ABOUT EDGE EFFECTS AND ULTRAMICROELECTRODES IN ELECTROCHEMISTRY: SYNERGY BETWEEN EXPERIMENTS AND SIMULATIONS

description: A short experimental activity aimed at upper level undergraduate students or beginner researchers is presented to introduce the concepts of edge effects and hemispherical diffusion at ultramicroelectrodes. Students will perform simple cyclic voltammetry experiments varying the scan rate and using disk electrodes with different radii. They are then asked to interpret the results based on their previous knowledge. Simulations are also performed, which provide a clear visual interpretation of the underlying diffusion process and show the transition between linear and hemispherical diffusion regimes. The simulations are also presented as a tool to extend the study beyond the range of experimentally accessible conditions. The interplay between voltammetry experiments and simulations allows a natural comprehension of these concepts without the need of a previous rigorous theoretical introduction.