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Currently, petroleum-derived plastics are widely used despite the disadvantage of their long degradation time. Natural polymers, however, can be used as alternatives to overcome this obstacle, particularly cornstarch. The tensile properties of cornstarch films can be improved by adding plant-derived nanofibers. Sisal (Agave sisalana), a very common low-cost species in Brazil, can be used to obtain plant nanofibers. The goal of this study was to obtain sisal nanofibers using low concentrations of sulfuric acid to produce thermoplastic starch nanocomposite films. The films were produced by a casting technique using commercial corn starch, glycerol, and sisal nanofibers, accomplished by acid hydrolysis. The effects of glycerol and sisal nanofiber content on the tensile mechanical properties of the nanocomposites were investigated. Transmission electron microscopy findings demonstrated that the lowest concentration of sulfuric acid produced fibers with nanometric dimensions related to the concentrations used. X-ray diffraction revealed that the untreated fibers and fibers subjected to acid hydrolysis exhibited a crystallinity index of 61.06 and 84.44%, respectively. When the glycerol and nanofiber contents were 28 and 1%, respectively, the tensile stress and elongation were 8.02 MPa and 3.4%. In general, nanocomposites reinforced with sisal nanofibers showed lower tensile stress and higher elongation than matrices without nanofibers did. These results were attributed to the inefficient dispersion of the nanofibers in the polymer matrix. Our findings demonstrate the potential of corn starch nanocomposite films in the packaging industry.
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Hydrothermal aging is a matter of considerable concern for natural fiber-reinforced polymers; it can alter dimensional stability and induce microcracks and macro strain on the composite structure. This study applied a sorption kinetic model and examined the effects of water on the damping factor of sisal mat-reinforced polyester composites. The experimental data were fitted well using a Boltzmann sigmoid function, suggesting a promising first step toward kinetic water sorption modeling. Additionally, a damping test was carried out using the impulse excitation technique, highlighting the composite material's dynamic response under varying water absorption conditions. The result showed that damping exhibited sensitivity to water absorption, increasing significantly during the first 24 h of immersion in water, then remained steady over time, inferring a critical time interval. An empirical model proved satisfactory with the correlation coefficient for sorption rates and damping of sisal mat polymeric composites.
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As a part of the mission to create materials that are more environmentally friendly, we present the following proposal, in which a study of the mechanical properties of composite materials comprising a polyester resin with sisal fiber and bentonite particles was conducted. Sisal fiber was added to a matrix in percentages ranging from 5% to 45% in relation to the polyester resin weight, while bentonite remained fixed at 7% in relation to the polyester resin weight. The specimens were manufactured by compression molding. The mechanical properties were analyzed by tensile, bending, impact, stepped creep, and relaxation tests. In addition, energy-dispersive X-ray spectroscopy and scanning electron microscopy analyses were carried out to analyze the composition and heterogeneity of the structure of the composite material. The results obtained showed that 7% of bentonite added to the matrix affects the tensile strength. Flexural strength increased by up to 21% in the specimens with a 20% addition of sisal fiber, while the elastic modulus increased by up to 43% in the case of a 20% addition of sisal fiber. The viscoelastic behavior was improved, while the relaxation stress was affected.
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OBJECTIVE: Sisal is a common stiff fibre produced around the world, corresponding to approximately 70% of the commercial production of all fibres of this type. The fibres are extracted from the leaves of Agave sisalana, from which approximately 4% of their weight is obtained, with the remaining 96% considered to be residues from the process of the sisal industry. The objective of this work was to obtain a polyphenol-enriched extract from the A. sisalana residue by ultrasonically assisted extraction, characterize it chemically, evaluate in vitro antioxidant activity, and develop safe and stable photoprotective formulations for future application in cosmetic preparations. METHODS: Ultrasonic extraction of solid plant material was performed using 50% ethanol/water (v/v). The extract was chemically characterized by high-performance liquid chromatography equipment associated with classical molecular networking and evaluated for in vitro antioxidant activity by different methodologies. Ten formulations were prepared, varying the component concentrations and the shear time. The 1.0% sisal extract was incorporated into the most stable formulations, and preliminary and accelerated stability were evaluated. The emulsions were investigated for safety by assessment of primary accumulated dermal irritability and sensitization and a dermatological clinical study of phototoxicity and photosensitization. The photoprotective formulations containing or not containing the extract that were stable after 90 days had their in vivo sun protection factor (SPF), UVA protection factor, critical wavelength, and protection against visible and blue light determined. RESULTS: Ultrasound extraction using 50% ethanol/water (EH 50) as an extractor vehicle showed the best yield. The extract exhibited a concentration of phenolic compounds (77.93 mg of equivalent to the standard gallic acid/g) and showed in vitro antioxidant activity. Emulsions without and with 1.0% sisal extract remained stable and safe. The addition of the extract to the photoprotective formulation statistically increased the SPF when compared to the formulation without the extract and offered protection against UVA radiation, critical wavelengths, and absorption of visible and blue light. CONCLUSION: Based on the findings, the solid residue of A. sisalana may be indicated as a component of photoprotective and antioxidant cosmetic formulations.
OBJECTIF: Le sisal est une fibre rigide courante produite dans le monde entier, correspondant à environ 70 % de la production commerciale de toutes les fibres de ce type. Les fibres sont extraites des feuilles d'Agave sisalana dont environ 4 % du poids est obtenu, les 96 % restants étant considérés comme des résidus du procédé de l'industrie du sisal. L'objectif de ce projet était d'obtenir un extrait du résidu d'A. sisalana enrichi en polyphénols par extraction assistée par ultrasons (EAU), de le caractériser chimiquement, d'évaluer l'activité antioxydante in vitro et de développer des formulations photoprotectrices sûres et stables pour une application future dans des préparations cosmétiques. MÉTHODES: L'extraction ultrasonique de la matière végétale solide a été effectuée avec une solution à 50 % d'éthanol/eau (v/v). L'extrait a été chimiquement caractérisé avec un équipement de chromatographie en phase liquide à haute performance associé à un réseau moléculaire (RM) classique, puis évalué pour l'activité antioxydante in vitro par différentes méthodologies. Dix formulations ont été préparées en variant les concentrations des composants et le temps de cisaillement. L'extrait de sisal à 1,0 % a été incorporé dans les formulations les plus stables et la stabilité préliminaire et accélérée a été évaluée. La sécurité d'emploi des émulsions a été étudiée en évaluant l'irritabilité et la sensibilisation cutanées accumulées primaires et l'étude clinique dermatologique de la phototoxicité et de la photosensibilisation. Le facteur de protection solaire in vivo, le facteur de protection UVA, la longueur d'onde critique et la protection contre la lumière visible et bleue ont été déterminées pour les formulations photoprotectrices contenant ou non l'extrait qui étaient stables après 90 jours. RÉSULTATS: L'extraction par ultrasons utilisant une solution à 50 % d'éthanol/eau (EH 50) comme véhicule d'extraction a menée au meilleur rendement. L'extrait a présenté une concentration de composés phénoliques (77,93 mg d'EAG/g) et une activité antioxydante in vitro. Les émulsions sans et avec 1,0 % d'extrait de sisal sont restées stables et sans danger. L'ajout de l'extrait à la formulation photoprotectrice a statistiquement augmenté le SPF par rapport à la formulation sans extrait et a offert une protection contre les rayonnements UVA, la longueur d'onde critique et l'absorption de la lumière visible et bleue. CONCLUSION: D'après ces résultats, les résidus solides d'A. sisalana peuvent être indiqués comme composant des formulations cosmétiques photoprotectrices et antioxydantes.
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Agave , Cosméticos , Resíduos Industriais , Agave/química , Antioxidantes/farmacologia , Extratos Vegetais , Etanol , ÁguaRESUMO
The dependence of the DS on the acid anhydride/anhydroglucose unit ((RCO)2O/AGU) molar ratio was correlated using second-order polynomials. The regression coefficients of the (RCO)2O/AGU terms showed that increasing the length of the RCO group of the anhydride led to lower values of DS. For acylation under heterogeneous reaction conditions, the following were employed: acid anhydrides and butyryl chloride as acylating agents; iodine as a catalyst; N,N-dimethylformamide (DMF) as a solvent, pyridine, and triethylamine as solvents and catalysts. For acylation using acetic anhydride plus iodine, the values of DS correlate with reaction time by a second-order polynomial. Due to its role as a polar solvent and a nucleophilic catalyst, pyridine was the most effective base catalyst, independent of the acylating agent (butyric anhydride and butyryl chloride).
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Celulose , Iodo , Cloretos , Acilação , Solventes , AnidridosRESUMO
The genus Agave presents a bimodal karyotype with x = 30 (5L, large, +25S, small chromosomes). Bimodality within this genus is generally attributed to allopolyploidy in the ancestral form of Agavoideae. However, alternative mechanisms, such as the preferential accumulation of repetitive elements at the macrochromosomes, could also be important. Aiming to understand the role of repetitive DNA within the bimodal karyotype of Agave, genomic DNA from the commercial hybrid 11648 (2n = 2x = 60, 6.31 Gbp) was sequenced at low coverage, and the repetitive fraction was characterized. In silico analysis showed that ~67.6% of the genome is mainly composed of different LTR retrotransposon lineages and one satellite DNA family (AgSAT171). The satellite DNA localized at the centromeric regions of all chromosomes; however, stronger signals were observed for 20 of the macro- and microchromosomes. All transposable elements showed a dispersed distribution, but not uniform across the length of the chromosomes. Different distribution patterns were observed for different TE lineages, with larger accumulation at the macrochromosomes. The data indicate the differential accumulation of LTR retrotransposon lineages at the macrochromosomes, probably contributing to the bimodality. Nevertheless, the differential accumulation of the satDNA in one group of macro- and microchromosomes possibly reflects the hybrid origin of this Agave accession.
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Agave , DNA Satélite , Agave/genética , Retroelementos , Cariótipo , CentrômeroRESUMO
Composites based on virgin and recycled polypropylene (PP and rPP) reinforced with 15 wt% sisal fibers, with and without alkali treatment, were prepared by compression molding in a mat composed of a three-layer sandwich structure. The sisal was characterized by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The composites were characterized according to physical and mechanical properties. Additionally, a factorial experimental design was used to statistically evaluate the mechanical properties of the composite. The FTIR and XRD indicated the partial removal of amorphous materials from the surface of the sisal after alkali treatment. The composites' density results varied from 0.892 to 0.927 g·cm-3, which was in the desirable range for producing lightweight automotive components. A slight decrease in the hardness of the pure rPP and rPP composites in relation to the PP was observed. The water absorption was higher in rPP composites, regardless of the chemical treatment. Moreover, the impact resistance of PP and its composites was higher than the values for rPP. Statistical analysis showed that the alkali treatment was a significant factor for the hardness of the rPP and PP composites, and that the addition of the sisal layer was relevant to improve the impact resistance of the composites.
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A presente produção versa sobre as consequências do racismo na saúde mental das mulheres negras integrantes do Movimento de Mulheres Dandara do Sisal (MMNDS), atuante no Território do Sisal, na Bahia. A intersecção de raça e gênero fomentou a organização do movimento, já que o gênero influi no racismo e a cor, no machismo; além do fato de as mulheres negras serem alvos de racismo e sexismo desde o período da escravização. A abordagem metodológica utilizada foi a descritiva-qualitativa, cujos métodos de coleta de dados foram entrevistas semiestruturadas com seis mulheres negras e observação participante de ações e atividades do movimento Dandara do Sisal. As entrevistadas relataram o racismo, a discriminação e o preconceito raciais que sofreram em suas trajetórias em diferentes espaços e instituições sociais: família, escola, universidade/faculdade, mercado de trabalho, dispositivos de saúde pública etc. Ser vítima de tais violências reflete negativamente na identidade negra, autoestima, subjetividade e saúde mental das atrizes sociais. Elas descreveram o sofrimento psíquico da exclusão social e a importância de estarem em movimento como estratégias de fortalecimento mental e enfrentamento ao racismo. Entende-se a Psicologia, enquanto ciência e profissão, como importante na luta antirracista, pois as consequências deletérias do racismo ameaçam a saúde mental e as subjetividades das mulheres e população negras.(AU)
This article discusses the consequences of racism on the mental health of black women members of the Dandara of Sisal Black Women Movement (MMNDS), which acts in the territory of Sisal, Bahia. The intersection of race and gender has fostered the movement's creation due to the gender impacting racism and the race affecting the sexism; as well as the fact that black women are victim of racism and sexism since the period of slavery. The methodological approach was qualitative and descriptive, with data collection methods by semi-structured interviews with six black women activists and participant observation of the Dandara of Sisal movement actions and activities. The women reported the racism, racial discrimination and prejudice that they suffered in their lives in different spaces and social institutions: family, school, university, job market, public health mechanisms etc. Being victim of such violence reflects negatively on the black identity, self-esteem, subjectivity, and mental health of these social actresses. They described the psychic suffering of social exclusion and the importance of being in the movement as strategies for mental empowerment and fight against the racism. Psychology is understood, as science and profession, as important in the anti-racist cause, since the deleterious effects of racism threaten the mental health and the subjectivity of black women and people.(AU)
Este texto se centra en las consecuencias del racismo en la salud mental de las mujeres negras miembros del Movimiento de Mujeres Negras Dandara do Sisal (MMNDS) que actúan en el Territorio do Sisal, en Bahía (Brasil). La intersección entre raza y género ha fomentado la organización del movimiento, ya que el género influye en el racismo, y el color en el machismo, además de que las mujeres negras han sido objeto de racismo y sexismo desde el período de la esclavitud. El enfoque metodológico utilizado fue descriptivo y cualitativo, para la recolección de datos se aplicaron entrevistas semiestructuradas con seis mujeres negras y la observación participante de acciones y actividades del movimiento Dandara do Sisal. Las entrevistadas denunciaron racismo, discriminación y discriminación racial, que sufrieron en sus trayectorias en diferentes espacios e instituciones sociales: familia, escuela, universidad/colegio, mercado laboral, dispositivos de salud pública, etc. Ser víctima de este tipo de violencia refleja negativamente en la identidad negra, la autoestima, la subjetividad y la salud mental de las actrices sociales. Las militantes describieron el sufrimiento psíquico de la exclusión social y la importancia de estar en un colectivo como estrategia para el fortalecimiento mental y la lucha contra el racismo. Se entiende que la Psicología, mientras ciencia y profesión, es importante en la lucha antirracista, ya que las consecuencias nocivas del racismo amenazan la salud mental y las subjetividades de las mujeres negras y la población negra.(AU)
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Humanos , Feminino , Mulheres , Saúde Mental , População Negra , Racismo , Psicologia , Fatores Socioeconômicos , Violência , Família , Cor , Feminismo , Sexismo , Discriminação Social , Escravização , Androcentrismo , EmpoderamentoRESUMO
Gram-negative, aerobic, rod-shaped, non-spore-forming, motile bacteria, designated CBAS 719 T, CBAS 732 and CBAS 720 were isolated from leaf litter samples, collected in Espírito Santo State, Brazil, in 2008. Sequences of the 16S rRNA, gyrB, lepA and recA genes showed that these strains grouped with Burkholderia plantarii LMG 9035 T, Burkholderia gladioli LMG 2216 T and Burkholderia glumae LMG 2196 T in a clade of phytopathogenic Burkholderia species. Digital DNA-DNA hybridization experiments and ANI analyses demonstrated that strain CBAS 719 T represents a novel species in this lineage that is very closely related with B. plantarii. The genome sequence of the type strain is 7.57 Mbp and its G + C content is 69.01 mol%. The absence of growth on TSA medium supplemented with 3% (w/v) NaCl, citrate assimilation, ß-galactosidase (PNPG) activity, and of lipase C14 activity differentiated strain CBAS 719 T from B. plantarii LMG 9035 T, its nearest phylogenetic neighbor. Its predominant fatty acid components were C16:0, C18:1 ω7c, cyclo-C17:0 and summed feature 3 (C16:1 ω7c and/or C15:0 iso 2-OH). Based on these genotypic and phenotypic characteristics, the strains CBAS 719 T, CBAS 732 and CBAS 720 are classified in a novel Burkholderia species, for which the name Burkholderia perseverans sp. nov. is proposed. The type strain is CBAS 719 T (= LMG 31557 T = INN12T).
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Antibiose , Burkholderia , Ecossistema , Agaricales/efeitos dos fármacos , Agaricales/fisiologia , Antibiose/fisiologia , Aspergillus/efeitos dos fármacos , Aspergillus/fisiologia , Técnicas de Tipagem Bacteriana , Brasil , Burkholderia/química , Burkholderia/classificação , Burkholderia/genética , DNA Bacteriano/genética , Fosfolipídeos/análise , Filogenia , Phytophthora/efeitos dos fármacos , Phytophthora/fisiologia , Folhas de Planta/microbiologia , RNA Ribossômico 16S/genética , Especificidade da Espécie , Compostos Orgânicos Voláteis/metabolismo , Compostos Orgânicos Voláteis/farmacologiaRESUMO
The heterogeneous structure of lignocellulosic biomass makes it difficult to dissolve its main components (cellulose, hemicelluloses, and lignin) by solvent action with the aim of further applying the mixture of the biological macromolecules generated in the solvent medium. In the present study, the dissolution efficiency (DE) of lignocellulosic sisal fibers in the lithium chloride/dimethylacetamide solvent system (LiCl/DMAc) was evaluated for further application in the formation of hydrogels. Catalytic amounts of trifluoroacetic acid (TFA) were used in some experiments, which increased the DE from 40% to 90%. The regeneration of the solutions, either previously filtered or not, led to hydrogels based on sisal lignocellulosic biomass. In brief, the properties of the hydrogels were influenced by the content of the lignocellulosic components in the hydrogels, present both in the dissolved fraction and in the incorporated undissolved fraction (when nonfiltered solutions were used). Hydrogels presented water absorption up to 7479% and resorption content in the lyophilized hydrogel up to 2133%. Extracts obtained from preselected hydrogels exhibited cell viability up to 127% compared to the control group when in contact with fibroblast cultures, exhibiting their noncytotoxic properties. This attribute increased the range of possible applications of these hydrogels, ranging from agriculture to biocompatible materials.
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Materiais Biocompatíveis/química , Hidrogéis/química , Lignina/química , Polissacarídeos/química , Agave/química , Materiais Biocompatíveis/farmacologia , Biomassa , Catálise , Cloreto de Lítio/química , Substâncias Macromoleculares/química , Substâncias Macromoleculares/farmacologia , Solventes/química , Água/químicaRESUMO
An on-line preconcentration system for the simultaneous determination of Copper (Cu) and manganese (Mn) in water samples was developed and coupled to a microwave-induced plasma optical emission spectrometer (MIP OES). The flow injection system was designed with a minicolumn packed with sisal fiber (Agave sisalana). A multivariate experimental design was performed to evaluate the influence of pH, preconcentration time, and eluent concentration. Optimal conditions for sample preparation were pH 5.5, preconcentration time was 90 s, and HCl 0.5 mol L-1 was the eluent. The main figures of merit were detection limits 3.7 and 9.0 µg L-1 for Cu and Mn, respectively. Precision was expressed as a relative standard deviation better than 10%. Accuracy was evaluated via spiked recovery assays with recoveries between 75-125%. The enrichment factor was 30 for both analytes. These results were adequate for water samples analysis for monitoring purposes. The preconcentration system was coupled and synchronized with the MIP OES nebulizer to allow simultaneous determination of Cu and Mn as a novel sample introduction strategy. The sampling rate was 20 samples/h. Sisal fiber resulted an economical biosorbent for trace element preconcentration without extra derivatization steps and with an awfully time of use without replacement complying with the principles of green analytical methods.
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Cobre/química , Química Verde/métodos , Manganês/química , Água/química , Concentração de Íons de Hidrogênio , Indicadores e Reagentes/química , Micro-Ondas , Plasma/química , Oligoelementos/químicaRESUMO
As a natural adsorbent, sisal (agave sisalana) fibers were used to extract Cu, Ni, Mn, and Zn from diesel oil samples for posterior determination (i.e., direct analytical measurements on the solid support) of the analytes by energy dispersive X-ray ï¬uorescence spectrometry (EDXRF). In the proposed procedure, 0.2 g of sisal fiber was directly added to 5.0 mL of diesel oil contained in a glass tube. After 5 min of contact time, the mixture was filtered, and the collected fibers were oven-dried for 30 min at 70 °C. After drying, the analytes were quantified directly by EDXRF using the sisal fibers as a solid support. The calibration curves showed linear concentration ranges of 0.09-1.00, 0.12-1.00, 0.09-1.00, 0.06-1.0 µg g-1 for Cu, Ni, Mn, and Zn, respectively. The limits of detection (LOD) for Cu, Ni, Mn, and Zn were 0.03, 0.04, 0.03, and 0.02 µg g-1, respectively. The repeatability, evaluated by performing ten measurements at a concentration of 0.50 µg g-1 for each metal, with the results expressed in terms of the relative standard deviation (RSD), was 3.2, 6.5, 6.8, and 6.1% for Cu, Ni, Mn, and Zn, respectively. The results obtained by the proposed method were compared with the results obtained by a comparative method using inductively coupled plasma optical emission spectrometry, and both results showed good agreement. The proposed method was applied for Ni, Cu, Mn, and Zn determination in diesel oil samples collected from different gas stations.
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Bovine papillomavirus (BPV) is the etiological agent of bovine papillomatosis, infectious disease characterized by the presence of benign tumors that can progress to malignancy. The phylogenetic classification of the PVs is performed based on the sequence homology of the Open Reading Frame L1, the most conserved among different viral serotypes. Given the immunogenicity of saponins, it,s has been used as a candidate as adjuvant use. For this reason, the safety of using saponin as an adjuvant has to be better determined to human or veterinary vaccine use. So, this study aimed to evaluate the mutagenic and genotoxic effect of saponins in comparison with the adjuvant widely used aluminum hydroxide using an isolated and purified L1 protein from BPV as model. In this study, genomic lesions, which after processed without repair can result in mutations, were detected by comet assay. Possible damages to genetic material caused by structural chromosomal changes (clastogenesis), as well as chromosomal losses (aneugenesis) were evaluated by the micronucleus test. Both tests were done on polychromatic erythrocytes and Vero cells. The evaluation of apoptosis and necrosis of treated Vero cells was made by Annexin V / PI staining and flow cytometry. The two vaccine products (L1 + Saponin and L1 + Aluminum Hydroxide) showed damages compatible with the positive control in the comet assay and both slightly elevated the micronucleus levels, in the Cell Viability Assay the results with Aluminum Hydroxide were satisfactory, characterizing Aluminum Hydroxide as a safer adjuvant according to the proposed tests, better than the saponins. Some fractions of the saponin extract separated by High Performance Liquid Chromatography were evaluated against genotoxic activity by comet assay, and their identities were confirmed by similarity to the reference standard by mass spectrometry.
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Space trusses are structural systems, generally made of tubes, used worldwide because of their advantages in covering long-span roofs. In addition to having a low cost, the truss weight is relatively reduced. The load capacity of these structures depends also on the strength of their node connection. Connections made with the superposition of flattened tube ends trespassed by one bolt are, generally, known as typical nodes. They are inexpensive but present eccentricities that reduce significantly the strength of such space trusses. To increase the truss load capacity, this research presents the results of an experimental program to reduce the eccentricities of the typical nodes. This reduction is done with a new type of spacer made of encapsulated concrete with steel fiber or sisal fiber. The experimental tests showed that the trusses with typical nodes collapsed under reduced load by local failure due to high distortions at the nodes. The trusses with encapsulated concrete spacer showed good results, with an increase in collapse load of 36% and failure by buckling bars.
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The main objective of this work was to investigate the effect of hybridization on the mechanical and thermal properties of intralaminar natural fiber-reinforced hybrid composites based on sisal. Ramie, sisal and curauá fibers were selected as natural fiber reinforcements for the epoxy matrix based composites, which were produced by the hand lay-up technique. Tensile, flexural and impact tests were carried out according to American society for testing and materials (ASTM) standards to characterize the hybrid composites, while differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to evaluate the thermal properties. It was found that the mechanical properties are improved by hybridization of sisal based composites. The thermal analysis showed that the hybridization did not significantly affect the thermal stability of the composites. A scanning electron microscopy (SEM) was used to examine the fracture surface of the tested specimens. The SEM images showed a brittle fracture of the matrix and fiber breakage near the matrix.
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Aspergillus welwitschiae is a species of the Nigri section of the genus Aspergillus. In nature, it is usually a saprotroph, decomposing plant material. However, it causes the bole rot disease of Agave sisalana (sisal), a plant species used for the extraction of hard natural fibers, causing great economic loss to this culture. In this study, we isolated and sequenced one genome of A. welwitschiae (isolate CCMB 674 (Collection of Cultures of Microorganisms of Bahia)) from the stem tissues of sisal and performed in silico and wet lab experimental strategies to describe its ability to produce mycotoxins. CCMB 674 possesses 64 secondary metabolite gene clusters (SMGCs) and, under normal conditions, it produces secondary metabolism compounds that could disturb the cellular cycle of sisal or induce abnormalities in plant growth, such as malformin C. This isolate also produces a pigment that might explain the characteristic red color of the affected tissues. Additionally, this isolate is defective for the production of fumonisin B1, and, despite bearing the full cluster for the synthesis of this compound, it did not produce ochratoxin A. Altogether, these results provide new information on possible strategies used by the fungi during the sisal bole rot, helping to better understand this disease and how to control it.
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Agave/crescimento & desenvolvimento , Agave/microbiologia , Aspergillus/genética , Aspergillus/metabolismo , Ciclo Celular/efeitos dos fármacos , Micotoxinas/biossíntese , Metabolismo Secundário , Sequência de Aminoácidos , BrasilRESUMO
The goal of this study was to investigate how the use of high concentration of cellulase may impact the properties of the substrate and the reaction medium during the enzymatic hydrolysis of the sisal pulp. Enzyme concentration of 0.9â¯mLâ¯g-1 was considered for hydrolysis of a sisal cellulosic substrate, and the results were compared with previous ones using 0.5â¯mLâ¯g-1 as cellulase concentration. Nonhydrolyzed pulps and the liquors were withdrawn from the reaction medium and characterized by scanning electron microscopy, crystallinity index, average molar mass, length/thickness, and high-performance liquid chromatography (HPLC). The results indicated that the enzyme/substrate ratio impacted crystallinity variations during the reaction and the induction period for exoglucanase action. The concentration of 0.9â¯mLâ¯g-1 led to a glucose yield (98%, an almost quantitative conversion) higher than 0.5â¯mLâ¯g-1 (89%). Aiming to gain information on the post-burst phase (after 15â¯h), 1â¯g of sisal pulp was added, and the results demonstrated that the enzymes remained active, which can counterbalance the higher cost due to the use of high enzymes concentrations. This study deepened the understanding of the enzymatic hydrolysis of sisal cellulosic pulp, and the findings may also benefit investigations on other pulps.
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Agave/química , Celulase/química , Celulose/química , Glucose/química , Hidrólise , Estrutura MolecularRESUMO
O sisal (Agave sisalana Perrine) é uma cultura de grande importância para o Semiárido do Brasil, constituindo-se como uma importante fonte de renda para regiões anteriormente sem opções de desenvolvimento. No entanto, estudos quanto ao manejo da cultura são escassos, refletindo na baixa tecnificação e práticas arcaicas no sistema de produção. Nesse contexto, o presente trabalho teve como finalidade avaliar o desempenho do crescimento inicial do Sisal (Agave sisalana Perrine) sob diferentes fontes de adubação (química e orgânica) e sob a presença e ausência de consórcio com feijão (Phaseolus vulgaris), no município de Areia, Paraíba. O experimento foi conduzido em delineamento em blocos casualizados (DBC), sob esquema fatorial 2x3, sendo dois sistemas de cultivo (solteiro ou consorciado com feijão) e três manejos de adubação (orgânico, mineral e sem adubação), constituindo assim seis tratamentos e quatro repetições, totalizando 24 parcelas, cada uma com área de 25 m². Os resultados evidenciaram a influência da fonte de adubação e do efeito do consórcio sob o desenvolvimento inicial da cultura, sendo os melhores resultados obtidos com adubação orgânica e consórcio com o feijão.
The Sisal (Agave sisalana Perrine) is a crop very important for the semi-arid region of Brazil, constituting an important source of income in regions that lack options that help in their development. However, studies regarding the development of this crop are scarce, reflecting on the low technology use and ancient practices used in the production systems. The object of this study was to evaluated the initial growth development of plants of Sisal (Agave sisalana Perrine) under different sources of chemical and organic fertilization and presence and absence of intercropping with common bean (Phaseolus vulgaris), in the city of Areia, Paraíba. The experiment was carried out in a randomized complete block design (RCBD), in a 2x3 factorial scheme, composed of two cultivation systems (alone or intercropped) and three fertilization types (organic, chemical and no fertilization), totaling 24 treatments with four replications in an area of 25 m² each. The results showed an influence effect of the source of fertilization and the intercroppingon the initial development of the crop, and the best results obtained were with the organic fertilization and the intercropping with common bean.
RESUMO
O sisal (Agave sisalana Perrine) é uma cultura de grande importância para o Semiárido do Brasil, constituindo-se como uma importante fonte de renda para regiões anteriormente sem opções de desenvolvimento. No entanto, estudos quanto ao manejo da cultura são escassos, refletindo na baixa tecnificação e práticas arcaicas no sistema de produção. Nesse contexto, o presente trabalho teve como finalidade avaliar o desempenho do crescimento inicial do Sisal (Agave sisalana Perrine) sob diferentes fontes de adubação (química e orgânica) e sob a presença e ausência de consórcio com feijão (Phaseolus vulgaris), no município de Areia, Paraíba. O experimento foi conduzido em delineamento em blocos casualizados (DBC), sob esquema fatorial 2x3, sendo dois sistemas de cultivo (solteiro ou consorciado com feijão) e três manejos de adubação (orgânico, mineral e sem adubação), constituindo assim seis tratamentos e quatro repetições, totalizando 24 parcelas, cada uma com área de 25 m². Os resultados evidenciaram a influência da fonte de adubação e do efeito do consórcio sob o desenvolvimento inicial da cultura, sendo os melhores resultados obtidos com adubação orgânica e consórcio com o feijão.(AU)
The Sisal (Agave sisalana Perrine) is a crop very important for the semi-arid region of Brazil, constituting an important source of income in regions that lack options that help in their development. However, studies regarding the development of this crop are scarce, reflecting on the low technology use and ancient practices used in the production systems. The object of this study was to evaluated the initial growth development of plants of Sisal (Agave sisalana Perrine) under different sources of chemical and organic fertilization and presence and absence of intercropping with common bean (Phaseolus vulgaris), in the city of Areia, Paraíba. The experiment was carried out in a randomized complete block design (RCBD), in a 2x3 factorial scheme, composed of two cultivation systems (alone or intercropped) and three fertilization types (organic, chemical and no fertilization), totaling 24 treatments with four replications in an area of 25 m² each. The results showed an influence effect of the source of fertilization and the intercroppingon the initial development of the crop, and the best results obtained were with the organic fertilization and the intercropping with common bean.(AU)
RESUMO
Interest in the use of renewable raw materials in the preparation of materials has been growing uninterruptedly in recent decades. The aim of this strategy is to offer alternatives to the use of fossil fuel-based raw materials and to meet the demand for materials that are less detrimental to the environment after disposal. In this context, several studies have been carried out on the use of lignocellulosic biomass and its main components (cellulose, hemicelluloses, and lignin) as raw materials for polymeric materials. Lignocellulosic fibers have a high content of cellulose, but there has been a notable lack of investigations on application of the electrospinning technique for solutions prepared from raw lignocellulosic biomass, even though the presence of cellulose favors the alignment of the fiber chains during electrospinning. In this investigation, ultrathin (submicrometric) and nanoscale aligned fibers were successfully prepared via electrospinning (room temperature) of solutions prepared with different contents of lignocellulosic sisal fibers combined with recycled poly(ethylene terephthalate) (PET) using trifluoroacetic acid (TFA) as solvent. The "macro" fibers were deconstructed by the action of TFA, resulting in solutions containing their constituents, i.e., cellulose, hemicelluloses, and lignin, in addition to PET. The "macro" sisal fibers were reconstructed at the nanometer and submicrometric scale from these solutions. The SEM micrographs of the mats containing the components of sisal showed distinct fiber networks, likely due to differences in the solubility of these components in TFA and in their dielectric constants. The mechanical properties of the mats (dynamic mechanical analysis, DMA, and tensile properties) were evaluated with the samples positioned both in the direction (dir) of and in opposition (op) to the alignment of the nano and ultrathin fibers, which can be considered a novelty in the analysis of this type of material. DMA showed superior values of storage modulus (E' at 30 °C) for the mats characterized in the preferential direction of fiber alignment. For example, for mats obtained from solutions prepared from a 0.4 ratio of sisal fibers/PET, Sisal/PET0.40dir presented a high E' value of 765 MPa compared to Sisal/PET0.40op that presented an E' value of 88.4 MPa. The fiber alignment did not influence the Tg values (from tan δ peak) of electrospun mats with the same compositions, as they presented similar values for this property. The tensile properties of the electrospun mats were significantly impacted by the alignment of the fibers: e.g., Sisal/PET0.40dir presented a high tensile strength value of 15.72 MPa, and Sisal/PET0.40op presented a value of approximately 2.5 MPa. An opposite trend was observed regarding the values of elongation at break for these materials. Other properties of the mats are also discussed; such as the index of fiber alignment, average porosity, and surface contact angle. To our knowledge, this is the first time that the influence of fiber alignment on the properties of electrospun mats based on untreated lignocellulosic biomass combined with a recycled polymer, such as PET, has been evaluated. The mats obtained in this study have potential for diversified applications, such as reinforcement for polymeric matrices in nanocomposites, membranes for filtration, and support for enzymes, wherein the fiber alignment, together with other evaluated properties, can impact their effectiveness in these applications.