cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14278958.v1
title: SYNTHESIS AND CHARACTERIZATION OF ENVIRONMENTALLY FRIENDLY QUANTUM DOTS, A SIMPLE WAY TO EXEMPLIFY AND EXPLORE NANOSCIENCE AND NANOTECHNOLOGY IN UNDERGRADUATE EDUCATION

description: Nanotechnologies and nanomaterials are very current and interesting topics and can be used as interdisciplinary tools in education. They can be used to work in a practical and interesting way with lots of subjects. In chemistry teaching it can be particularly important to consolidate the nanomaterials, nanotechnology and characterization teaching. Among the nanomaterials, quantum dots (QDs) can be highlighted due to their interesting optical and electronical properties. Some of the topics that can be discussed related to them are the nanoparticles synthesis, spectroscopies and optical characterization, X-ray diffractometry and structural characterization, surface ligands, semiconductor materials, electronic transition, solid crystalline structure, colloidal synthesis, among many other subjects. The application of the experiment of synthesis and characterization of environmentally friendly quantum dots to students of the discipline “Solid State Chemistry” of the chemistry undergraduate course, allowed the contact of students with materials of great technological interest. Being a material widely studied by various research groups around the world. The experiment proved to be an interesting way to introduce students to a material of great technological interest, in a simple and accessible way. It aroused the interest of the students while allowing the practical application of the acquired knowledge.
DOI: 10.6084/m9.figshare.14278962
title: LIMONENE QUANTIFICATION BY GAS CHROMATOGRAPHY WITH MASS SPECTROMETRY (GC-MS) AND ITS EFFECTS ON HYDROGEN AND VOLATILE FATTY ACIDS PRODUCTION IN ANAEROBIC REACTORS

description: The inhibition effect of limonene on the organisms involved in anaerobic reactors may affect obtaining H2 in this process. Rapid and precise limonene quantification is desirable to characterize wastewaters. The objective of this research was to develop a Gas Chromatography Coupled to Mass Spectrometry (GC-MS) method to determine limonene concentration in liquid samples from batch reactors applied to H2 production at 30 ºC. Method validation was carried out through calibration curves (3 to 20 mg L-1of limonene), in addition to evaluating its precision (CV =0.1%), linearity (R2=0.979), limits of detection (1.7 mg L-1) and quantification (4.2 mg L-1). Its inhibitory effect was evaluated with increasing concentrations of limonene (without addition to 2000 mg L-1). Limonene affected the starting time of H2 production (λ), since λ was 8.7 h in control assays and 15 h with 2000 mg L-1 of limonene. The same was observed for obtaining H2, since 19.5 mmol H2 L-1 was obtained in control assays and 8.7 mmol H2 L-1 was obtained in assays with 2000 mg L-1 of limonene. This method was effective for limonene determination in liquid samples from batch reactors and could be used for characterization and control of anaerobic reactors.
DOI: 10.6084/m9.figshare.14278961.v1
title: WOMEN SCIENTISTS IN THE BRAZILIAN CHEMISTRY

description: Brazil’s gender gaps numbers are scarce in the field of chemistry. Thus, the motivation of this work is to perform a data survey considering all levels of the academic career and per Brazilian region. The data collected shows a general trend observed in all scenarios, whereas the higher the career level the lower the number of women inserted. Women dominate in the early stages of the scientific careers, such as postgraduate programs (52%) but become minority (42%) when they get positions as university professors. The disparity is higher at positions of great recognition, e.g., member of the Brazilian Academy of Science (18%) or the highest level of CNPQ research productivity fellowship “1A” (12%). Other career indicators such as research grants approval, authorship in recognized international journals and in highly cited articles authored by Brazilian scientists, show low female representativity. Leadership positions in scientific societies and funding agencies are alarming (6%), where many organizations never had a woman president. The world needs more female references in science and surely Brazil has many great women in the field of chemistry that deserve recognition. The present study sheds light to the awareness of the Brazilian scenario.
DOI: 10.6084/m9.figshare.14278962.v1
title: LIMONENE QUANTIFICATION BY GAS CHROMATOGRAPHY WITH MASS SPECTROMETRY (GC-MS) AND ITS EFFECTS ON HYDROGEN AND VOLATILE FATTY ACIDS PRODUCTION IN ANAEROBIC REACTORS

description: The inhibition effect of limonene on the organisms involved in anaerobic reactors may affect obtaining H2 in this process. Rapid and precise limonene quantification is desirable to characterize wastewaters. The objective of this research was to develop a Gas Chromatography Coupled to Mass Spectrometry (GC-MS) method to determine limonene concentration in liquid samples from batch reactors applied to H2 production at 30 ºC. Method validation was carried out through calibration curves (3 to 20 mg L-1of limonene), in addition to evaluating its precision (CV =0.1%), linearity (R2=0.979), limits of detection (1.7 mg L-1) and quantification (4.2 mg L-1). Its inhibitory effect was evaluated with increasing concentrations of limonene (without addition to 2000 mg L-1). Limonene affected the starting time of H2 production (λ), since λ was 8.7 h in control assays and 15 h with 2000 mg L-1 of limonene. The same was observed for obtaining H2, since 19.5 mmol H2 L-1 was obtained in control assays and 8.7 mmol H2 L-1 was obtained in assays with 2000 mg L-1 of limonene. This method was effective for limonene determination in liquid samples from batch reactors and could be used for characterization and control of anaerobic reactors.
DOI: 10.6084/m9.figshare.14278964
title: CHARACTERIZATION OF INTERACTION BETWEEN BUDDLEOSIDE AND BOVINE SERUM ALBUMIN

description: The primary objective of this study was to investigate the binding of buddleoside to bovine serum albumin (BSA) by different analytical techniques. The analytical principles of affinity capillary electrophoresis (ACE) and fluorescence spectroscopy used in the experiments were different. Mobility (M) that is independent of viscosity of the operating buffer and voltage was chosen to eliminate the effects of electroosmotic flow (EOF) in ACE and was applied to estimate the binding constant Ka. The quenching constant Ksv, binding site number n and binding constant Kb were provided by the fluorescence quenching method. After data analysis of the fluorescence quenching process, it can be seen that the quenching of BSA by buddleoside is a static quenching method. The binding constants between buddleoside and BSA obtained from ACE and fluorescence spectra were 1.218×105 and 1.1915×105, respectively. According to the thermodynamic parameters of ΔG, ΔH and ΔS, it can be inferred that Van Der Waals force and hydrogen bonding force exist in the interaction between buddleoside and BSA. This study can provide a reference for the study of the transport and function mechanism of buddleoside in vivo.
DOI: 10.6084/m9.figshare.14278964.v1
title: CHARACTERIZATION OF INTERACTION BETWEEN BUDDLEOSIDE AND BOVINE SERUM ALBUMIN

description: The primary objective of this study was to investigate the binding of buddleoside to bovine serum albumin (BSA) by different analytical techniques. The analytical principles of affinity capillary electrophoresis (ACE) and fluorescence spectroscopy used in the experiments were different. Mobility (M) that is independent of viscosity of the operating buffer and voltage was chosen to eliminate the effects of electroosmotic flow (EOF) in ACE and was applied to estimate the binding constant Ka. The quenching constant Ksv, binding site number n and binding constant Kb were provided by the fluorescence quenching method. After data analysis of the fluorescence quenching process, it can be seen that the quenching of BSA by buddleoside is a static quenching method. The binding constants between buddleoside and BSA obtained from ACE and fluorescence spectra were 1.218×105 and 1.1915×105, respectively. According to the thermodynamic parameters of ΔG, ΔH and ΔS, it can be inferred that Van Der Waals force and hydrogen bonding force exist in the interaction between buddleoside and BSA. This study can provide a reference for the study of the transport and function mechanism of buddleoside in vivo.
DOI: 10.6084/m9.figshare.14278967
title: ESSENTIAL OIL OF CURCUMA LONGA L. RHIZOMES CHEMICAL COMPOSITION, YIELD VARIATION AND STABILITY

description: Turmeric (Curcuma longa L.) is a medicinal plant that is cultivated worldwide. This study was conducted to evaluate the variability in the percentage and the chemical composition of volatile oils from 12 turmeric samples. Rhizomes of the turmeric plant were collected from three different producers in the Brazilian like savanna (Cerrado) habitat in the state of Bahia. The chemical composition of the oils derived from the rhizomes was analysed by thin-layer chromatography and GC-MS. The average oil content was 3.97% ± 0.61%, varying from 3.0% to 5.16%. There were differences between producers; however, all samples met the specification of the Brazilian Pharmacopoeia. Thin-layer chromatographic analysis revealed qualitative similarity in both oil and curcuminoid components among the samples. The major components identified in the oils by gas chromatography were ar-turmerone (40.00% ± 13.20%), α-turmerone (10.05% ± 2.90%) and curlone (22.73% ± 12.72%). Regarding stability, there was a difference between the essential oil percentages after 6 months, but the content was maintained adequate and the chromatographic profile remained similar. The vegetable raw material obtained from C. longa rhizomes produced in the western region of the state of Bahia met the quality requirement of the Brazilian Pharmacopoeia.
DOI: 10.6084/m9.figshare.14278961
title: WOMEN SCIENTISTS IN THE BRAZILIAN CHEMISTRY

description: Brazil’s gender gaps numbers are scarce in the field of chemistry. Thus, the motivation of this work is to perform a data survey considering all levels of the academic career and per Brazilian region. The data collected shows a general trend observed in all scenarios, whereas the higher the career level the lower the number of women inserted. Women dominate in the early stages of the scientific careers, such as postgraduate programs (52%) but become minority (42%) when they get positions as university professors. The disparity is higher at positions of great recognition, e.g., member of the Brazilian Academy of Science (18%) or the highest level of CNPQ research productivity fellowship “1A” (12%). Other career indicators such as research grants approval, authorship in recognized international journals and in highly cited articles authored by Brazilian scientists, show low female representativity. Leadership positions in scientific societies and funding agencies are alarming (6%), where many organizations never had a woman president. The world needs more female references in science and surely Brazil has many great women in the field of chemistry that deserve recognition. The present study sheds light to the awareness of the Brazilian scenario.
DOI: 10.6084/m9.figshare.14278966
title: ELECTRICAL NOISES REDUCTION IN NANOPORES EXPERIMENTS BASED ON CONSENSUS FILTER

description: Nanopore has developed into an indispensable tool for single molecules experiments, where useful information about the characteristics of DNA/RNA can be obtained from the flowing of ionic current elicited by individual molecules as they traverse a single nanometer-scale aperture. However, due to the relatively high background current noise and low measurement bandwidth, it is difficult to distinguish the molecule-specific signals from the intrinsic noises of the nanopore recording systems, which impeded its application in DNA sequencing. In this paper, we present a novel consensus filter-based noise reduction approach, which considerably improves the accuracy of the noise-filtered current traces and the signal-to-noise ratios (SNRs). The new approach is compared to the conventional Bessel filters and validated by analyzing simulated representative translocation data as well as alpha-Hemolysin (α-HL) nanopore experimental data. It is demonstrated that the high frequency noise generated by the voltage noise of the amplifier and Analog-to-Digital converter circuits (ADC) can be significantly reduced and some hidden short-lived translocation events can be recovered with satisfying accuracy beyond the conventional limitations of the Bessel filters.
DOI: 10.6084/m9.figshare.14278967.v1
title: ESSENTIAL OIL OF CURCUMA LONGA L. RHIZOMES CHEMICAL COMPOSITION, YIELD VARIATION AND STABILITY

description: Turmeric (Curcuma longa L.) is a medicinal plant that is cultivated worldwide. This study was conducted to evaluate the variability in the percentage and the chemical composition of volatile oils from 12 turmeric samples. Rhizomes of the turmeric plant were collected from three different producers in the Brazilian like savanna (Cerrado) habitat in the state of Bahia. The chemical composition of the oils derived from the rhizomes was analysed by thin-layer chromatography and GC-MS. The average oil content was 3.97% ± 0.61%, varying from 3.0% to 5.16%. There were differences between producers; however, all samples met the specification of the Brazilian Pharmacopoeia. Thin-layer chromatographic analysis revealed qualitative similarity in both oil and curcuminoid components among the samples. The major components identified in the oils by gas chromatography were ar-turmerone (40.00% ± 13.20%), α-turmerone (10.05% ± 2.90%) and curlone (22.73% ± 12.72%). Regarding stability, there was a difference between the essential oil percentages after 6 months, but the content was maintained adequate and the chromatographic profile remained similar. The vegetable raw material obtained from C. longa rhizomes produced in the western region of the state of Bahia met the quality requirement of the Brazilian Pharmacopoeia.
DOI: 10.6084/m9.figshare.14278970
title: BTEX IMPACTS IN URBAN AREAS OF THE CITY OF RIO DE JANEIRO

description: Most volatile organic compounds (VOC) have adverse effects on human health and the environment and react individually with different velocities and mechanisms to form ozone. The present work determined the concentration of 55 samples of benzene, toluene, ethylbenzene and xylenes (BTEX), an important subgroup of VOC, by active sampling with active carbon cartridge in the areas of Barra da Tijuca, Deodoro and Maracana between the months of December 2014 to September 2015. The samples were extracted with dichloromethane and analyzed by gas chromatography coupled to mass spectrometry (GC-MS). The percentage distribution of BTEX showed toluene as the most abundant compound in the three sites, with 54, 3% in Barra da Tijuca, 57, 4% in Deodoro and 38, 1% in the Maracana area of the total BTEX. The mean benzene/toluene (B/T) ratios were 0.12 (Maracana), 0.37 (Barra da Tijuca) and 0.23 (Deodoro), confirming the emission source as predominantly vehicular. Using reactivity scales, toluene was the compound that most contributed to the formation of ozone and benzene was less reactive than the others. The carcinogenic risk was considered indifferent in all sites.
DOI: 10.6084/m9.figshare.14278970.v1
title: BTEX IMPACTS IN URBAN AREAS OF THE CITY OF RIO DE JANEIRO

description: Most volatile organic compounds (VOC) have adverse effects on human health and the environment and react individually with different velocities and mechanisms to form ozone. The present work determined the concentration of 55 samples of benzene, toluene, ethylbenzene and xylenes (BTEX), an important subgroup of VOC, by active sampling with active carbon cartridge in the areas of Barra da Tijuca, Deodoro and Maracana between the months of December 2014 to September 2015. The samples were extracted with dichloromethane and analyzed by gas chromatography coupled to mass spectrometry (GC-MS). The percentage distribution of BTEX showed toluene as the most abundant compound in the three sites, with 54, 3% in Barra da Tijuca, 57, 4% in Deodoro and 38, 1% in the Maracana area of the total BTEX. The mean benzene/toluene (B/T) ratios were 0.12 (Maracana), 0.37 (Barra da Tijuca) and 0.23 (Deodoro), confirming the emission source as predominantly vehicular. Using reactivity scales, toluene was the compound that most contributed to the formation of ozone and benzene was less reactive than the others. The carcinogenic risk was considered indifferent in all sites.
DOI: 10.6084/m9.figshare.14278966.v1
title: ELECTRICAL NOISES REDUCTION IN NANOPORES EXPERIMENTS BASED ON CONSENSUS FILTER

description: Nanopore has developed into an indispensable tool for single molecules experiments, where useful information about the characteristics of DNA/RNA can be obtained from the flowing of ionic current elicited by individual molecules as they traverse a single nanometer-scale aperture. However, due to the relatively high background current noise and low measurement bandwidth, it is difficult to distinguish the molecule-specific signals from the intrinsic noises of the nanopore recording systems, which impeded its application in DNA sequencing. In this paper, we present a novel consensus filter-based noise reduction approach, which considerably improves the accuracy of the noise-filtered current traces and the signal-to-noise ratios (SNRs). The new approach is compared to the conventional Bessel filters and validated by analyzing simulated representative translocation data as well as alpha-Hemolysin (α-HL) nanopore experimental data. It is demonstrated that the high frequency noise generated by the voltage noise of the amplifier and Analog-to-Digital converter circuits (ADC) can be significantly reduced and some hidden short-lived translocation events can be recovered with satisfying accuracy beyond the conventional limitations of the Bessel filters.
DOI: 10.6084/m9.figshare.14278972
title: SYNTHESIS AND PHYTOTOXIC PROFILE OF A NEW TETRAOXANE DESIGNED FROM A COMMERCIAL AUXIN

description: Modern agriculture relies on the massive use of agrochemicals, including herbicides. Despite their effectiveness, a continuous use of herbicides sharing the same target has resulted in the selection of weed biotypes resistant to such chemicals. To cope with this problem, the development of new herbicides is an urgent requirement. In this work we applied the Active compound Derivatization Method (ADM) strategy to develop a new tetraoxane (5), derived from the synthetic auxin 2-(naphtalen-1-yl)acetic acid (NAA). Greenhouse bioassays showed that 5 caused chlorosis, necrosis and leaf epinasty in Cucumis sativa. Furthermore, this compound, at the concentration of 1.25 x 10-5 mol L-1, inhibited the growth of important weeds such as Bidens pilosa, Iponomea acuminate, Solanum americanum and Althernantera ficoidea. For some weeds, the compound effect was higher or comparable to those caused by commercial glyphosate and imazethapyr. In addition, degradation studies revealed that 5 is transformed into NAA. The results also showed that 5 could act as photosynthesis inhibitor and as an auxin herbicide. In summary, we have discovered a new compound that may be a useful lead for the development of a commercial herbicide.
DOI: 10.6084/m9.figshare.14278975
title: CHARACTERIZATION AND QUALITY CONTROL OF COPAIBA OILS (COPAIFERA SP.) BY RELATIVE RETENTION FACTOR BY HPTLC TO DETECTION OF BIOMARKERS

description: Copaiba oilresins present medicinal uses that demand the development of methodologies that could ensure the authenticity and guarantee the species differentiation. The usual way to differentiate the copaiba oils is analyze the terpene composition, mainly the diterpenic acids profile. Unlike caryophyllene and its oxide, copaiba diterpenes are not commercially available and lab obtention is expensive and time consuming. At this paper, a new methodology is presented that allows the fast and reliable detection of copaiba biomarkers using HPTLC retention factor relative to an appropriate standard. Several commercially available substances were analyzed and the monoterpene linalool oxide was chosen. The comparison of relative retention factors allowed the confirmation of caryophyllene and its oxides and the diterpenic acids copalic, hydroxy-copalic, acetoxy-copalic, agathic, and hardwickiic. Calibration curve showed strong correlation (│r│ ≥0.9962) with R2 ≥0.9928.
DOI: 10.6084/m9.figshare.14278975.v1
title: CHARACTERIZATION AND QUALITY CONTROL OF COPAIBA OILS (COPAIFERA SP.) BY RELATIVE RETENTION FACTOR BY HPTLC TO DETECTION OF BIOMARKERS

description: Copaiba oilresins present medicinal uses that demand the development of methodologies that could ensure the authenticity and guarantee the species differentiation. The usual way to differentiate the copaiba oils is analyze the terpene composition, mainly the diterpenic acids profile. Unlike caryophyllene and its oxide, copaiba diterpenes are not commercially available and lab obtention is expensive and time consuming. At this paper, a new methodology is presented that allows the fast and reliable detection of copaiba biomarkers using HPTLC retention factor relative to an appropriate standard. Several commercially available substances were analyzed and the monoterpene linalool oxide was chosen. The comparison of relative retention factors allowed the confirmation of caryophyllene and its oxides and the diterpenic acids copalic, hydroxy-copalic, acetoxy-copalic, agathic, and hardwickiic. Calibration curve showed strong correlation (│r│ ≥0.9962) with R2 ≥0.9928.
DOI: 10.6084/m9.figshare.14278977
title: A SALTING-OUT ASSISTED LIQUID-LIQUID EXTRACTION FOR THE DETERMINATION OF TEBUCONAZOLE, CARBOFURAN AND IMIDACLOPRID IN WHITE AND ROSÉ WINES

description: Food safety is a constant and necessary concern due to the worldwide increase of the food demand. The monitoring of quality parameters demands the development of accurate, easy and fast procedures. The aim of this work was to develop a cheap, miniaturized and trustworthy salting-out assisted liquid-liquid extraction (SALLE) procedure for the determination of pesticides in wines. Sample and acetonitrile were mixed and the addition of NaCl and CH3COONa were used for separation of aqueous and organic phases. After centrifugation, the organic phase was directly injected into a liquid chromatograph. The developed SALLE procedure consumed at least 25-fold less reagent compared to conventional QuEChERS procedure. Additionally, the d-SPE step of the QuEChERS method was suppressed, without efficiency losses. The developed procedure was compared to the conventional methodology and no significant difference was observed. It was successfully applied to the determination of three pesticides in wines by liquid chromatography. Low consumption of sample and solvent, low residues generation, simple instrumentation are notable advantages. The suppression of the d-SPE step simplified the process and the risk of analyte losses.