cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.11997225
title: NEW APPLICATIONS FOR AMOXICILLIN DETERMINATION IN PURE FORM AND PHARMACEUTICALS BASED ON IODATE-IODIDE MIXTURE: TITRIMETRY AND SPECTROSCOPY STUDIES

description: Three simple methods are described for the determination of amoxicillin (AMX) in bulk drug and dosage forms using iodate-iodide mixture reagent. These methods employed the well-known analytical reaction between iodate-iodide mixture in the presence of acid solution. The iodide oxidized by iodate to iodine in an amount equivalent to the -COOH group present in amoxicillin (AMX) and the liberated iodine determined by titrimetry and spectrophotometry. In the titrimetric method (method A), the liberated iodine was reacted with a measured excess of thiosulphate and the residual thiosulphate was determined by titration with a standard iodine solution using starch indicator, the method was applicable over 2 - 16 mg of AMX. In the second and third methods, the absorbance of the liberated iodine was measured at 370 nm (method B) and also iodine was reacted with starch and starch-iodine complex was measured at 570 nm (method C). In spectrophotometric methods (B and C), Beer’s law was obeyed over the concentration range of 5 - 50 and 5 - 60 µg mL-1 AMX with a molar absorptivity values of 5.55×103 L mol-1 cm-1 and 4.76×103 L mol-1 cm-1 for the method A and method B, respectively. The limits of detection (LOD) and quantification (LOQ) were calculated for method B and method C. The proposed methods were found to yield reliable results when applied to bulk drug and dosage forms analysis, and hence they can be applied in quality control laboratories.
DOI: 10.6084/m9.figshare.11997393.v1
title: NANO-ENCAPSULATION OF Lippia origanoides KUNTH. ESSENTIAL OIL BY CHITOSAN-CAFFEIC ACID NANOGEL

description: In this study, a nanogel was developed from a natural polymer, chitosan, to be used in the Lippia origanoides essential oil encapsulation. The encapsulation process was used in order to improve the functional capacity of this essential oil as an antioxidant. To obtain the nanogel, the chitosan was modified with caffeic acid using EDC coupling agent. The obtained material was characterized by FTIR and TGA, revealing the formation of the chitosan-caffeic acid bond. The size, morphology and essential oil amount incorporated to the nanogel were investigated by DLS, SEM and gravimetric analysis, respectively. SEM and gravimetric analysis indicated that oil were efficiently trapped inside the CS-CA matrix, with encapsulation efficiency of 42 ± 2%. The EDL studies showed that the encapsulation of essential oil in the nanogel significantly affected your structure, with a average particle size of 417.26 ± 55.96. After essential oil incorporation into the CS-CA nanogel it was also observed a increase in its antioxidant capacity in terms of elimination of DPPH and ABTS radicals, and ferric reducing antioxidant power (FRAP). The successful development of this CS-CA nanogel loaded with L. origanoides essential oil will lead to a better applicability of this essential oil as an effective antioxidant.
DOI: 10.6084/m9.figshare.11997903
title: A RENEWABLE CATALYST FOR A RENEWABLE CHEMICAL: GRAM-SCALE CONVERSION OF FURFURAL TO FURFURYL ALCOHOL BY THE CARROT (Daucus carota)

description: The bioconversion of furfural to furfuryl alcohol using only carrot bits in water at room temperature and ambient pressure is presented. This reaction led to the bioreduction of furfural with 99% conversion and 99% selectivity to an alcohol. This simple and “fully” green process may represent an alternative to classic hydrogenation processes. Also, without work-up procedure, we demonstrate the aqueous solution can be submitted to microwave irradiation to obtain 4-hydroxy-2-cyclopentenone.
DOI: 10.6084/m9.figshare.11997903.v1
title: A RENEWABLE CATALYST FOR A RENEWABLE CHEMICAL: GRAM-SCALE CONVERSION OF FURFURAL TO FURFURYL ALCOHOL BY THE CARROT (Daucus carota)

description: The bioconversion of furfural to furfuryl alcohol using only carrot bits in water at room temperature and ambient pressure is presented. This reaction led to the bioreduction of furfural with 99% conversion and 99% selectivity to an alcohol. This simple and “fully” green process may represent an alternative to classic hydrogenation processes. Also, without work-up procedure, we demonstrate the aqueous solution can be submitted to microwave irradiation to obtain 4-hydroxy-2-cyclopentenone.
DOI: 10.6084/m9.figshare.11997225.v1
title: NEW APPLICATIONS FOR AMOXICILLIN DETERMINATION IN PURE FORM AND PHARMACEUTICALS BASED ON IODATE-IODIDE MIXTURE: TITRIMETRY AND SPECTROSCOPY STUDIES

description: Three simple methods are described for the determination of amoxicillin (AMX) in bulk drug and dosage forms using iodate-iodide mixture reagent. These methods employed the well-known analytical reaction between iodate-iodide mixture in the presence of acid solution. The iodide oxidized by iodate to iodine in an amount equivalent to the -COOH group present in amoxicillin (AMX) and the liberated iodine determined by titrimetry and spectrophotometry. In the titrimetric method (method A), the liberated iodine was reacted with a measured excess of thiosulphate and the residual thiosulphate was determined by titration with a standard iodine solution using starch indicator, the method was applicable over 2 - 16 mg of AMX. In the second and third methods, the absorbance of the liberated iodine was measured at 370 nm (method B) and also iodine was reacted with starch and starch-iodine complex was measured at 570 nm (method C). In spectrophotometric methods (B and C), Beer’s law was obeyed over the concentration range of 5 - 50 and 5 - 60 µg mL-1 AMX with a molar absorptivity values of 5.55×103 L mol-1 cm-1 and 4.76×103 L mol-1 cm-1 for the method A and method B, respectively. The limits of detection (LOD) and quantification (LOQ) were calculated for method B and method C. The proposed methods were found to yield reliable results when applied to bulk drug and dosage forms analysis, and hence they can be applied in quality control laboratories.
DOI: 10.6084/m9.figshare.14278781
title: Percutaneous solutions for biliary stent dysfunction: pictorial essay

description: Abstract Plastic and metal biliary stents can fail to function properly, such failure being due to a positioning error or to the migration, occlusion, or fracture of the stent. An obstructed biliary stent can act as a nidus, causing complications such as recurrent persistent cholangitis. It can also cause vascular complications (such as bleeding and the formation of pseudoaneurysms), perforate the liver capsule (causing biloma or abscess), or, in rare cases, cause intestinal obstruction or perforation. In this pictorial essay, we demonstrate various interventional radiology techniques for the treatment of biliary stent dysfunction in patients with obstructive biliary disease.
DOI: 10.6084/m9.figshare.14278781.v1
title: Percutaneous solutions for biliary stent dysfunction: pictorial essay

description: Abstract Plastic and metal biliary stents can fail to function properly, such failure being due to a positioning error or to the migration, occlusion, or fracture of the stent. An obstructed biliary stent can act as a nidus, causing complications such as recurrent persistent cholangitis. It can also cause vascular complications (such as bleeding and the formation of pseudoaneurysms), perforate the liver capsule (causing biloma or abscess), or, in rare cases, cause intestinal obstruction or perforation. In this pictorial essay, we demonstrate various interventional radiology techniques for the treatment of biliary stent dysfunction in patients with obstructive biliary disease.
DOI: 10.3886/e121922v1-82180
title: Data and Code for: Social Media, News Consumption, and Polarization: Evidence from a Field Experiment

description: Does the consumption of ideologically congruent news on social media exacerbate polarization? I estimate the effects of social media news exposure by conducting a large field experiment randomly offering participants subscriptions to conservative or liberal news outlets on Facebook. I collect data on the causal chain of media effects: subscriptions to outlets, exposure to news on Facebook, visits to online news sites, and sharing of posts, as well as changes in political opinions and attitudes. Four main findings emerge. First, random variation in exposure to news on social media substantially affects the slant of news sites individuals visit. Second, exposure to counter-attitudinal news decreases negative attitudes toward the opposing political party. Third, in contrast to the effect on attitudes, I find no evidence that the political leanings of news outlets affect political opinions. Fourth, Facebook's algorithm is less likely to supply individuals with posts from counter-attitudinal outlets, conditional on individuals subscribing to them. Together, the results suggest that social media algorithms may limit exposure to counter-attitudinal news and thus increase polarization.<br>
DOI: 10.6084/m9.figshare.11997660
title: INFLUENCE OF THE STERIC HINDRANCE OF ANCILLARY LIGANDS IN Ru-BASED COMPLEXES APPLIED IN METATHESIS OF CINNAMYL ALCOHOL AND CINNAMYL ACETATE

description: Cinnamyl alcohol (AC) and cinnamyl acetate (ACM) were used as substrates in olefin metathesis reactions catalyzed by RuCl2(PCy3)2(=CHPh), first-generation Grubbs catalyst-G1, and RuCl2(PCy3)(H2IMes)(= CHPh), second-generation Grubbs catalyst-G2. The reactions occurred in the same reaction conditions for both substrates, 50 °C, for 24 h, in the proportions Ru:substrate of 1:1 and 1:10 mol. At the end of each experiment, the reaction mixture was evaluated by GC-MS and NMR of 13C{1H}. The results revealed different products when G1 and G2 are applied in the metathesis of AC, 1,5-diphenyl-2-pentene and stilbene, respectively. When ACM is the substrate, no product is noted with G1 and stilbene was the compound obtained with G2 as catalyst. In this study, we have presented a discussion about the electronic and steric influence of the ancillary ligands in the yield and type of product formed in the catalytic process.
DOI: 10.6084/m9.figshare.11997912
title: CALYSTEGINES, POLYHYDROXYLATED ALCALOIDS PRESENT IN VEGETABLES: FRUITS AND TUBERS

description: Calystegines are nortropane alkaloids with three to five hydroxyl groups. These alkaloids are recognized as glycosidase inhibitors and thus may have therapeutic potential to be exploited. There are also reports of its possible toxic effects when they are present in foods. Commercial cultivars of human consumption in Brazil have been analyzed for calystegines content. Samples of Solanum tuberosum L. (potato), Ipomoea batatas L. (sweet potato), Solanum lycopersicum (tomato), Solanum melongena (eggplant) and Solanum aethiopicum L. (gilo) were obtained from local markets in Rio de Janeiro, RJ, Brazil. Qualitative analyzes were performed by gas chromatography coupled to mass spectrometry (GC/MS) and high performance liquid chromatography coupled to mass spectrometry (LC/MS). Gas chromatography with flame ionization detector (GC/FID) was used in quantitative analysis. Five calystegines (A3, B1, B2, B4 and C1) were detected in the whole sample set and the amounts of three of them were determined: A3 (1.94-15.88 mg kg-1); B2 (7.59-23.7 mg kg-1) and B4 (3.61-9.38 mg kg-1). This is the first report on the occurrence of these alkaloids in Solanum aethiopicum L.
DOI: 10.6084/m9.figshare.11997525
title: SYNTHESIS, ANTILESHMANIA AND CYTOTOXIC ACTIVITY OF HYDRAZONES FROM NATURAL ALDEHYDES

description: Leishmaniasis is endemic anthropozoonosis considered to be a severe public health problem. The treatment with pentavalent antimonials presents high toxicity motivating the search for effective and less toxic drugs. Hydrazones and N-acylhydrazones are functional groups that are prominent in Medicinal Chemistry, including as antiprotozoals. In this context, five hydrazones derived from the natural aldehydes were synthesized and the molecular structures were suitably determined to employ uni and bidimensional 1H and 13C NMR techniques. The antileishmanial activity of all hydrazones was determined against promastigote forms of Leishmania amazonensis, and the compounds HDZ-3, HDZ-4, and HDZ-5 showed the best results, with IC50 of 9.00, 38.10 and 26.30 µM, respectively. In the cytotoxic evaluation against RAW macrophages, HDZ-4 presented the least cytotoxic (CC50 = 222.24 µM) and the higher selectivity. Lipinski’s descriptors of the hydrazones were calculated, and the compounds HDZ-3 and HDZ-5 were more promising. These hydrazones are hybrids of natural aldehydes with drugs, the first is the result of the junction of the cinnamaldehyde with isoniazid, and the second of the vanillin with hydralazine. The results highlighted the Markush isonicotinoylhydrazone and phthalazinylhydrazone groups, molecular structures that are present in HDZ-3 and HDZ-5 and are therefore considered innovators in the development of antileishmanial drugs.
DOI: 10.6084/m9.figshare.11997912.v1
title: CALYSTEGINES, POLYHYDROXYLATED ALCALOIDS PRESENT IN VEGETABLES: FRUITS AND TUBERS

description: Calystegines are nortropane alkaloids with three to five hydroxyl groups. These alkaloids are recognized as glycosidase inhibitors and thus may have therapeutic potential to be exploited. There are also reports of its possible toxic effects when they are present in foods. Commercial cultivars of human consumption in Brazil have been analyzed for calystegines content. Samples of Solanum tuberosum L. (potato), Ipomoea batatas L. (sweet potato), Solanum lycopersicum (tomato), Solanum melongena (eggplant) and Solanum aethiopicum L. (gilo) were obtained from local markets in Rio de Janeiro, RJ, Brazil. Qualitative analyzes were performed by gas chromatography coupled to mass spectrometry (GC/MS) and high performance liquid chromatography coupled to mass spectrometry (LC/MS). Gas chromatography with flame ionization detector (GC/FID) was used in quantitative analysis. Five calystegines (A3, B1, B2, B4 and C1) were detected in the whole sample set and the amounts of three of them were determined: A3 (1.94-15.88 mg kg-1); B2 (7.59-23.7 mg kg-1) and B4 (3.61-9.38 mg kg-1). This is the first report on the occurrence of these alkaloids in Solanum aethiopicum L.
DOI: 10.6084/m9.figshare.14278783
title: Applications of the Dixon technique in the evaluation of the musculoskeletal system

description: Abstract The acquisition of images with suppression of the fat signal is very useful in clinical practice and can be achieved in a variety of sequences. The Dixon technique, unlike other fat suppression techniques, allows the signal of fat to be suppressed in the postprocessing rather than during acquisition, as well as allowing the visualization of maps showing the distribution of water and fat. This review of the Dixon technique aims to illustrate the basic physical principles, to compare the technique with other magnetic resonance imaging sequences for fat suppression or fat quantification, and to describe its applications in the study of diseases of the musculoskeletal system. Many variants of the Dixon technique have been developed, providing more consistent separation of the fat and water signals, as well as allowing correction for many confounding factors. It allows homogeneous fat suppression, being able to be acquired in combination with several other sequences, as well as with different weightings. The technique also makes it possible to obtain images with and without fat suppression from a single acquisition. In addition, the Dixon technique can be used as a quantitative method, allowing the proportion of tissue fat to be determined, and, in more updated versions, can quantify tissue iron.
DOI: 10.6084/m9.figshare.14278783.v1
title: Applications of the Dixon technique in the evaluation of the musculoskeletal system

description: Abstract The acquisition of images with suppression of the fat signal is very useful in clinical practice and can be achieved in a variety of sequences. The Dixon technique, unlike other fat suppression techniques, allows the signal of fat to be suppressed in the postprocessing rather than during acquisition, as well as allowing the visualization of maps showing the distribution of water and fat. This review of the Dixon technique aims to illustrate the basic physical principles, to compare the technique with other magnetic resonance imaging sequences for fat suppression or fat quantification, and to describe its applications in the study of diseases of the musculoskeletal system. Many variants of the Dixon technique have been developed, providing more consistent separation of the fat and water signals, as well as allowing correction for many confounding factors. It allows homogeneous fat suppression, being able to be acquired in combination with several other sequences, as well as with different weightings. The technique also makes it possible to obtain images with and without fat suppression from a single acquisition. In addition, the Dixon technique can be used as a quantitative method, allowing the proportion of tissue fat to be determined, and, in more updated versions, can quantify tissue iron.
DOI: 10.6084/m9.figshare.11997540
title: ANALYTICAL EXPRESSIONS FOR THE CONCENTRATION AND CURRENT IN THE REDUCTION OF HYDROGEN PEROXIDE AT A METAL-DISPERSED CONDUCTING POLYMER FILM

description: A mathematical model describing the reduction of Hydrogen peroxide (H2O2) to water in a metal dispersed conducting polymer film is discussed. The model is based on a system of reaction-diffusion equations containing a non-linear term related to Michaelis-Menten kinetics of the enzymatic reaction. The approximate analytical expressions corresponding to the concentration of substrate and product for steady and non-steady state conditions have been obtained using a new approach to homotopy perturbation method (HPM). Approximate analytical expressions of the electrochemical oxidation current are also presented for steady and non-steady state conditions. The numerical simulation (Matlab program) response for concentration profiles was carried out and compared with the analytical results of this work and are found to be in good agreement. The influence of initial substrate concentration, the thickness of the film as well as the diffusion layer and kinetic parameters on the current response were investigated. A graphical procedure for estimating the kinetic parameters from the expression of the current response is also proposed.
DOI: 10.6084/m9.figshare.11997660.v1
title: INFLUENCE OF THE STERIC HINDRANCE OF ANCILLARY LIGANDS IN Ru-BASED COMPLEXES APPLIED IN METATHESIS OF CINNAMYL ALCOHOL AND CINNAMYL ACETATE

description: Cinnamyl alcohol (AC) and cinnamyl acetate (ACM) were used as substrates in olefin metathesis reactions catalyzed by RuCl2(PCy3)2(=CHPh), first-generation Grubbs catalyst-G1, and RuCl2(PCy3)(H2IMes)(= CHPh), second-generation Grubbs catalyst-G2. The reactions occurred in the same reaction conditions for both substrates, 50 °C, for 24 h, in the proportions Ru:substrate of 1:1 and 1:10 mol. At the end of each experiment, the reaction mixture was evaluated by GC-MS and NMR of 13C{1H}. The results revealed different products when G1 and G2 are applied in the metathesis of AC, 1,5-diphenyl-2-pentene and stilbene, respectively. When ACM is the substrate, no product is noted with G1 and stilbene was the compound obtained with G2 as catalyst. In this study, we have presented a discussion about the electronic and steric influence of the ancillary ligands in the yield and type of product formed in the catalytic process.
DOI: 10.6084/m9.figshare.11997525.v1
title: SYNTHESIS, ANTILESHMANIA AND CYTOTOXIC ACTIVITY OF HYDRAZONES FROM NATURAL ALDEHYDES

description: Leishmaniasis is endemic anthropozoonosis considered to be a severe public health problem. The treatment with pentavalent antimonials presents high toxicity motivating the search for effective and less toxic drugs. Hydrazones and N-acylhydrazones are functional groups that are prominent in Medicinal Chemistry, including as antiprotozoals. In this context, five hydrazones derived from the natural aldehydes were synthesized and the molecular structures were suitably determined to employ uni and bidimensional 1H and 13C NMR techniques. The antileishmanial activity of all hydrazones was determined against promastigote forms of Leishmania amazonensis, and the compounds HDZ-3, HDZ-4, and HDZ-5 showed the best results, with IC50 of 9.00, 38.10 and 26.30 µM, respectively. In the cytotoxic evaluation against RAW macrophages, HDZ-4 presented the least cytotoxic (CC50 = 222.24 µM) and the higher selectivity. Lipinski’s descriptors of the hydrazones were calculated, and the compounds HDZ-3 and HDZ-5 were more promising. These hydrazones are hybrids of natural aldehydes with drugs, the first is the result of the junction of the cinnamaldehyde with isoniazid, and the second of the vanillin with hydralazine. The results highlighted the Markush isonicotinoylhydrazone and phthalazinylhydrazone groups, molecular structures that are present in HDZ-3 and HDZ-5 and are therefore considered innovators in the development of antileishmanial drugs.
DOI: 10.6084/m9.figshare.11997540.v1
title: ANALYTICAL EXPRESSIONS FOR THE CONCENTRATION AND CURRENT IN THE REDUCTION OF HYDROGEN PEROXIDE AT A METAL-DISPERSED CONDUCTING POLYMER FILM

description: A mathematical model describing the reduction of Hydrogen peroxide (H2O2) to water in a metal dispersed conducting polymer film is discussed. The model is based on a system of reaction-diffusion equations containing a non-linear term related to Michaelis-Menten kinetics of the enzymatic reaction. The approximate analytical expressions corresponding to the concentration of substrate and product for steady and non-steady state conditions have been obtained using a new approach to homotopy perturbation method (HPM). Approximate analytical expressions of the electrochemical oxidation current are also presented for steady and non-steady state conditions. The numerical simulation (Matlab program) response for concentration profiles was carried out and compared with the analytical results of this work and are found to be in good agreement. The influence of initial substrate concentration, the thickness of the film as well as the diffusion layer and kinetic parameters on the current response were investigated. A graphical procedure for estimating the kinetic parameters from the expression of the current response is also proposed.
DOI: 10.6084/m9.figshare.11997636
title: CANNABINOIDS QUANTIFICATION IN MEDICINAL Cannabis EXTRACTS BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

description: Cannabidiol (CBD) and tetrahydrocannabinol (THC) are the main active principles in the Cannabis extracts. Rich-CBD extracts are indicated to control seizures in epileptic patients, THC is indicated as antiemetic to patients in chemotherapy treatment and extracts with THC and CBD in proportions of approximately 1:1 are indicated to control spasticity in patients with multiple sclerosis. In Brazil epileptic pediatric patients are treated with imported Cannabis extracts registered as food supplement and with national not regulated Cannabis extracts. With the medical Cannabis sanitary regulation in Brazil, quality control methods will be required. A High Performance Liquid Chromatography (HPLC) method was developed and validated for five cannabinoids quantification in oily extracts and resins. The method was applied to 101 Cannabis extracts consumed by patients attended by a risk assessment program. Linearity, selectivity and precision met the validation criteria of national and international sanitary agencies. Cannabis imported oily extracts showed high CBD levels (72.53±60.63 mg mL-1) and low THC levels (1.21±1.32 mg mL-1), while national Cannabis extracts showed mainly two profiles, first composed by negative or cannabinoids traces and the second composed by THC rich extracts (9.81±13.49 mg mL-1). The HPLC method is useful to pharmaceutical production and risk assessment purposes.