THERMOGRAVIMETRIC ANALYSIS OF THERMAL AND KINETIC BEHAVIOR OF ACACIA MANGIUM WOOD

Thermogravimetric analysis was used to study the thermal behavior of Acacia mangium wood under inert atmosphere at heating rates ranging from 5 to 15C min -1, from room temperature to 800C. Weight losses of A. mangium wood in inert atmosphere were found to occur in three stages. These three states are generally associated with the decomposition of the three main components of the lignocellulosic materials. Most decomposition occurred in the range of 300-400C (80% weight approximately). The kinetic parameters of the process were evaluated using the independent parallel reaction model, attributed to the three main components of lignocellulosic materials: hemicelluloses, cellulose, and lignin. The values of activation energy, preexponential factor, and contribution factor were similar to those reported in other studies for this type of biomass. The model proposed predicted an acceptable correlation between the experimental and the calculated curve to the decomposition of A. mangium, with an error of less than 3% of deviation in the temperature range studied

Experiments on torrefaction of Dichrostachys cinerea wood: two-level factorial design and thermogravimetric analysis

The aim of this study was to determine the effect of the temperature and reaction time variables on the solid yield and the increment of heating values and composition of torrefied Dichrostachys cinerea wood by using a factorial experiment design and thermogravimetric analysis. The significant factors were identified by means of a two-level factorial design type (22), for which the statistical software Design Expert version 10 was used. Torrefaction and thermogravimetric experimental runs were carried out in a fixed-bed reactor and thermobalance TGA–DTA, respectively. Torrefaction temperature, residence time and their interaction have a significant effect on solid yield, whilst the effect of the temperature was the only statistically significant factor on increment at a high heating value (HHV). The R-Squared values for both response variables were greater than 95% in each case. An increase in torrefied biomass was achieved at HHVs of 14.92 and 30.31% under the conditions of 120 min at 250 and 290 °C, respectively. Thermogravimetric characterisation and DTG–TG curves of the torrefied material suggest that the pre-treated material has been modified chemically and structurally.This research was financed by a doctoral scholarship from the Università Politecnica Delle Marche, Ancona, Italy, and supported by the Department of Chemical Engineering, University of Alicante, Alicante, Spain

Traditional use of medicinal plants by the population of the municipality of Santa Clara, Cuba

Context: Ethnobotanical studies are the basis for the acquisition of knowledge about the use of medicinal plants. Aims: To characterize the traditional use of medicinal plants by the population of the municipality of Santa Clara, Cuba. Methods: A field research in nine districts of Santa Clara municipality, Villa Clara province, Cuba was conducted. A questionnaire to key informants from urban and rural localities of both genders, civil status and educational levels, was applied; the sampling was intentional. The Use Value Index and the Significant Use Level were calculated. Results: Ninety-one species of medicinal plants belonging to 27 families were identified; Lamiaceae (13), Compositae (12) and Vervenaceae (6) were the most represented. The most used parts of the plants were leaves (58%) and roots (10%). The most cited preparation technique was the decoction (56.7%). The most frequently cited mixtures were: leaves with flowers in 4% and leaves with roots in 3%. The most treated diseases by the population were respiratory, including bronchial asthma (25.4%), followed by gastrointestinal (23.6%). 19% of the key informants recognized that there were plants contraindicated due to their toxicity. 29.6% of the total species reported showed a significant level of use higher than 20%, so they can be considered important for scientific evaluation and validation. Conclusions: Ninety-one species belonging to 27 families were identified; Lamiaceae, Compositae and Verbenaceae were the most represented. The most used parts of the plants were leaves and roots. The decoction technique was the most cited. The most treated disorders were respiratory and gastrointestinal. 29.6% of the reported species showed significant levels of use greater than 20%

PROPUESTA PARA CONTRIBUIR AL USO EFICIENTE DE LOS PORTADORES ENERGÉTICOS EN LA EMPRESA AGROPECUARIA DE CABAIGUÁN

La investigación se realizó a partir de la necesidad de estudiar el comportamiento energéticode la Empresa Agropecuaria Cabaiguán y con el objetivo de proponer un plan de accionesque contribuya al consumo eficiente de portadores energéticos la entidad.Se aplicó la prueba de necesidad como primer paso de la Tecnología de Gestión TotalEficiente de la Energía.Como resultados se mostró que el diesel fue el portador energético de mayor peso dentro dela estructura de consumo con más del 87 %, se propusieron cinco ecuaciones con R2 ≥ 0.75que muestran la dependencia entre el consumo de diesel y la preparación de tierra, laproducción de leche, las actividades de servicio, el riego y las actividades administrativas.Además se identificaron las principales causas de los altos consumos energéticos quesirvieron de base para proponer ocho acciones que permitirán a la empresa proyectarsehacia el consumo eficiente de portadores energéticos

Physico-chemical characterisation of Capparis scabrida seed oil and pulp, a potential source of eicosapentaenoic acid

6 Tablas.-- 2 FigurasThe main nutraceutical properties were determined for Capparis scabrida fruit seed oil to evaluate the potential of this species as an unconventional source of plant oil. Nutritional properties were compared with commercial edible oils. The fatty acid composition was determined using gas chromatography analysis. The total phenolic content (TPC) and antioxidant activity were determined using the Folin-Ciocalteu method and using radical scavenging activity: 1,1-diphenyl-2- picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays, respectively. The statistical tools of cluster and discriminant analysis were used to classify C. scabrida seed oil in comparison with other seed oils. The C. scabrida seed has 31.5% lipid, of which 52.8% is oleic acid. Eicosapentaenoic acid, which is uncommon in the plant kingdom, was found. The omega-6 (7.87%):omega-3 (2.97%) ratio was 2.7:1, which is consistent with recent dietary guidelines. The TPC, DPPH and ABTS value were 150 mg gallic acid equivalents kg−1, 1.11 and 1.94 mM Trolox kg−1, respectively, for C. scabrida seed oil.This study was supported by the Universidad Estatal Amazónica, Puyo, Ecuador. We appreciate the comments of the reviewers and Editor-in-Chief who have contributed to improving the manuscript through the peer-review process.Peer reviewe

Thermogravimetric analysis of thermal and kinetic behavior of acácia mangium wood

Thermogravimetric analysis was used to study the thermal behavior of Acacia mangium wood under inert atmosphere at heating rates ranging from 5 to 15C min -1, from room temperature to 800C. Weight losses of A. mangium wood in inert atmosphere were found to occur in three stages. These three states are generally associated with the decomposition of the three main components of the lignocellulosic materials. Most decomposition occurred in the range of 300-400C (80% weight approximately). The kinetic parameters of the process were evaluated using the independent parallel reaction model, attributed to the three main components of lignocellulosic materials: hemicelluloses, cellulose, and lignin. The values of activation energy, preexponential factor, and contribution factor were similar to those reported in other studies for this type of biomass. The model proposed predicted an acceptable correlation between the experimental and the calculated curve to the decomposition of A. mangium, with an error of less than 3% of deviation in the temperature range studied47919COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES002/201

Honey quality parameters, chemical composition and antimicrobial activity in twelve Ecuadorian stingless bees (Apidae: Apinae: Meliponini) tested against multiresistant human pathogens

[EN] Ecuadorian honey samples of eight genera and 12 stingless bee species from three geographic regions (Andes, Amazon and Pacific) were studied for their physicochemical parameters, chemical composition, mineral elements and antimicrobial activity. Meliponine honey is acidic and has a high water content, but our study revealed substantial chemical variation. Oxytrigona mellaria was highest in proteins, while Melipona sp. had the most free amino acid content. Five species of honey contained vitamin C, which was highest in O. mellaria. The most abundant minerals were the macronutrients, potassium and calcium. All honey inhibited microbial growth in gram-negative and gram-positive multiresistant human pathogens, with O. mellaria and Trigona silvestriana being most effective against both bacteria

Evaluation of the polyphenolic profile of native Ecuadorian stingless bee honeys (Tribe: Meliponini) and their antibiofilm activity on susceptible and multidrug-resistant pathogens: An exploratory analysis

Biofilms are associated with infections that are resistant to conventional therapies, contributing to the antimicrobial resistance crisis. The need for alternative approaches against biofilms is well-known. Although natural products like stingless bee honeys (tribe: Meliponini) constitute an alternative treatment, much is still unknown. Our main goal was to evaluate the antibiofilm activity of stingless bee honey samples against multidrug-resistant (MDR) pathogens through biomass assays, fluorescence (cell count and viability), and scanning electron (structural composition) microscopy. We analyzed thirty-five honey samples at 15% (v/v) produced by ten different stingless bee species (Cephalotrigona sp., Melipona sp., M. cramptoni, M. fuscopilosa, M. grandis, M. indecisa, M. mimetica, M. nigrifacies, Scaptotrigona problanca, and Tetragonisca angustula) from five provinces of Ecuador (Tungurahua, Pastaza, El Oro, Los Ríos, and Loja) against 24-h biofilms of Staphylococcus aureus, Klebsiella pneumoniae, Candida albicans, and Candida tropicalis. The present honey set belonged to our previous study, where the samples were collected in 2018–2019 and their physicochemical parameters, chemical composition, mineral elements, and minimal inhibitory concentration (MIC) were screened. However, the polyphenolic profile and their antibiofilm activity on susceptible and multidrug-resistant pathogens were still unknown. According to polyphenolic profile of the honey samples, significant differences were observed according to their geographical origin in terms of the qualitative profiles. The five best honey samples (OR24.1, LR34, LO40, LO48, and LO53) belonging to S. problanca, Melipona sp., and M. indecisa were selected for further analysis due to their high biomass reduction values, identification of the stingless bee specimens, and previously reported physicochemical parameters. This subset of honey samples showed a range of 63–80% biofilm inhibition through biomass assays. Fluorescence microscopy (FM) analysis evidenced statistical log reduction in the cell count of honey-treated samples in all pathogens (P <0.05), except for S. aureus ATCC 25923. Concerning cell viability, C. tropicalis, K. pneumoniae ATCC 33495, and K. pneumoniae KPC significantly decreased (P <0.01) by 21.67, 25.69, and 45.62%, respectively. Finally, scanning electron microscopy (SEM) analysis demonstrated structural biofilm disruption through cell morphological parameters (such as area, size, and form). In relation to their polyphenolic profile, medioresinol was only found in the honey of Loja, while scopoletin, kaempferol, and quercetin were only identified in honey of Los Rios, and dihydrocaffeic and dihydroxyphenylacetic acids were only detected in honey of El Oro. All the five honey samples showed dihydrocoumaroylhexose, luteolin, and kaempferol rutinoside. To the authors’ best knowledge, this is the first study to analyze stingless bees honey-treated biofilms of susceptible and/or MDR strains of S. aureus, K. pneumoniae, and Candida species