Abstract The objective of this research was to develop a more sustainable composite and still keep its characteristics. Fibers treated with NaOH at 5% w/w for 2 hours were incorporated into natural rubber in different proportions (0 phr, 24 phr, 36 phr, 48 phr and 60 phr). The mechanical properties of the composites suffered changes, increasing the hardness, young’s modulus and decreasing its tensile strength. All the physical properties were not statistically different. The coloration became less dark in the WF60/CB0 treatment, and the electrical properties presented better resistivity with the increase in the concentration of fibers in the composite. This presents a possibility of using WF for the production of wood-rubber composites for the production of rubber artifacts which do not require high rolling resistance. Based on the results from this research, we recommended the WF24/CB36 mix to produce antistatic floors.

The biodiversity of plant resources is a renewable source that can use as a sustainable component in various applications. The use of vegetable waste as a filler element in polymeric composites is part of the solid waste management policy and the sustainable development of agribusiness. In this work, the natural rubber composites were prepared with acai seed in proportions of 0, 10, 20, 30, 40, and 50 phr (per hundred rubber). The composites were homogenized in an open cylinder mixer and characterized by rheometric, morphological, mechanical, and thermal tests. The addition of the organic fillers significantly reduced the vulcanization process time. Thermogravimetric analysis and infrared spectroscopy showed that the composites were thermally stable and showed no structure changes after the vulcanization process, respectively. The Lorenz-Parks method's evaluation of matrix/filler interactions showed a strong interaction between NR/Acai. The new biocomposite can replace non-ecological composites economically and sustainably.

RESUMO Em virtude dos índices de produção da cana-de-açúcar, o bagaço proveniente do processamento da cana na indústria sucroalcooleira é hoje o resíduo agroindustrial produzido em maior volume no Brasil. Em 2019 foram gerados cerca de 192 milhões de toneladas deste resíduo. A utilização deste resíduo tem sido alvo de pesquisas em todo o mundo, com destaque às aplicações que visam atender as prerrogativas do conceito de economia circular. Dentro desse cenário, o bagaço de cana-de açúcar (SB) foi tratado em meio alcalino, formando um material adsorvente, SBNaOH. Os efeitos do tratamento químico foram avaliados quanto a propriedades de superfície e quanto a remoção do herbicida glifosato em meio aquoso. O fenômeno adsortivo foi estudado por meio de ensaios de isotermas. Os resultados obtidos foram ajustados aos modelos clássicos de Langmuir, Freundlich e Dubinin-Radushkevich, onde cada material adsorvente se encaixou em um modelo diferente. A caracterização indicou que o tratamento químico promoveu alteração importante na superfície do resíduo, ampliando a área superficial. SB e o SBNaOH tiveram um comportamento favorável como adsorvente e boa performance na remoção do herbicida, apresentando valores maiores que 65% de em todas as condições de trabalho. A saturação teórica de adsorção regida por Dubinin-Radushkevich (qS) foi na ordem de 8,988 mg/g (R2=0,988) para o SB aos 120 minutos de contato e capacidade máxima encontrada por Langmuir (Qmáx) foi de 13,720 mg/g (R2=0,984) para o SBNaOH aos 40 minutos de contato. O processo foi governado por troca ou partilha de elétrons. O adsorvato se distribui de forma heterogênea na superfície SB, justificando a presença sítios ativos com maior força iônica, e homogeneamente sobre a superfície (monocamada) de SBNaOH. Em geral, o bagaço de cana tratado, provindo de um resíduo agroindustrial, se mostrou um biosorvente alternativo e promissor para remoção de glifosato de sistemas aquosos, gerando assim uma nova aplicação deste resíduo.

ABSTRACT Due to the production rates of sugarcane, nowadays, the sugarcane bagasse stemming in the sugar and alcohol industry is the agro-industrial waste produced in greater volume throughout in Brazil. In 2019, about 192 million tons of this waste were generated. The use of this waste has been the aim of researches around the world, with emphasis on applications that aim to meet the prerogatives of the concept of circular economy. Within this scenario, sugarcane bagasse (SB) was treated in an alkaline medium, forming an adsorbent material, SBNaOH. The effects of chemical treatment were evaluated for surface properties and for glyphosate removal in an aqueous medium. The adsorptive phenomenon was studied through isotherm tests. The results obtained were fitted to classical models of Langmuir, Freundlich and Dubinin-Radushkevich. The characterization indicated that the chemical treatment promoted an important change in the surface of the residue, increasing the surface area. SB and SBNAOH had a feasible behavior as adsorbent and good performance in the removal of the herbicide, presenting values greater than 65% of under all working conditions. The theoretical adsorption saturation governed by Dubinin-Radushkevich (qS) was in the order of 8.988 mg/g (R2=0.988) for SB at 120 minutes of contact and maximum adsorption capacity by Langmuir (Qmax) was 13.720 mg/g (R2=0.984) for SBNaOH at 40 minutes of contact. The process was governed by the exchange or sharing of electrons. The adsorbate is distributed heterogeneously on the SB surface, justifying the presence of active sites with greater ionic strength, and homogeneously on the SBNaOH surface (monolayer). In general, the treated sugarcane bagasse, coming from an agro-industrial residue, proved to be an alternative and promising biosorbent for the removal of glyphosate from aqueous systems, thus generating a new application of this residue.

Abstract There is a great demand to develop different techniques for the continuous removal, immobilization, and remediation of metallic ions from contaminated water. Human contamination by metallic ions could even occur by ingestion of seafood causing carcinogenic and mutagenic activities. In this study, a nanofibrous membrane of poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) produced by electrospinning technique and coated with polyaniline (PAni) was tested for the removal of chromium in low-concentration solutions. The viability of ZFL cells (zebrafish liver cells) was performed to evaluate the water quality enhancement after chromium adsorption. The results indicated that the nanofibrous membrane successfully adsorbed the chromium species in low-concentration ( Q e= 2.44 mg/g, at pH 4.5, room temperature (RT) and 24h) by Freundlich model and followed a pseudo-second-order kinetics model indicating a possible chemisorption in multilayers, at pH 4.5, RT and [CrVI] = 5.0 mg/L. At pH 2.0 (24h, RT and [CrVI] = 5.0 mg/L), the membrane adsorbed around 91.64% of CrVI contaminants. The thermodynamic studies revealed that the process was spontaneous and exothermic. The cells viability demonstrated the efficiency of the membrane tested in the aquatic ecosystem protection; the viability increased 19.2% in 5.0 mg/L CrVI solution. Thus, the results of this study shows that the nanofibrous membrane can be an alternative to remove low concentration of CrVI from aqueous solutions.

Abstract This paper investigated the formation of crosslinks in natural rubber compounds in the vulcanization systems: conventional (CV), semi-efficient (SEV), and efficient (EV), processed with three types of accelerators: MBTS (dibenzothiazole disulfide), TMTD (tetramethylthiuram disulfide) and CBS (n-cyclohexyl 2-benzothiazole sulfenamide). The cross-linked densities were determined by organic solvent swelling, dynamic mechanical analysis (DMA), stress vs strain, and low-field nuclear magnetic resonance, the latter being the reference technique for comparison with the other results. It was found that the choice of accelerator type influences the processing time and the cross-linked density of the vulcanizate. The four techniques showed close values of cross-linked density for natural rubber compounds, demonstrating that the analytical techniques studied can be applied to determine cross-linked density.

SUMMARY: Severe muscle injuries are common in accidents and have a delayed recovery of muscle integrity. In these cases, muscle suture surgery is the standard treatment. However, Platelet Rich Plasma (PRP), has been widely used in orthopedic injuries due to its growth factors. Thus, the objective of the study will be to analyze the association of suture and PRP techniques in the collagen and tenacity of the injured muscle. Were used seventy rats, divided into five groups: control (C), injury control (CI), injury and suture (IS), injury and PRP (IP), injury, suture, and PRP (ISP). Were sectioned approximately 50 % of the width and 100 % of the thickness of the gastrocnemius muscle. The homologous PRP was applied 24h after the injury. On the 7th day after the injury, the animals were euthanized and their muscles subjected to mechanical testing to measure tenacity or collagen analysis to calculate the ratio between type I and III collagen. The results show a significant decrease (p <0.05) in the values of the relationship between collagens in all injured groups (CI, IS, IP, ISP) compared to group C. In injured groups, the tenacity was significantly (p <0.05) reduced compared to the control group, with no observed difference between treatments and injured groups. The amount of collagen in the injured area has increased, but it did not affect the tenacity of the muscles, which was reduced.

RESUMEN: Las lesiones musculares graves son comunes durante los accidentes y la integridad del músculo está sujeta a una larga recuperación. En esos casos la cirugía, para la sutura del músculo, es el tratamiento común, no obstante el plasma rico en plaquetas (PRP) ha sido utilizado recientemente en lesiones ortopédicas, debido a sus factores del crecimiento. El objetivo del estudio fue analizar la asociación de las técnicas de sutura y PRP en la histología y tenacidad de músculo lesionado. Fueron utilizadas 70 ratas distribuidas en cinco grupos: control (C), control lesión (CL), lesión y sutura (LS), lesión y PRP (LPRP), lesión, sutura y PRP (LSPRP). Aproximadamente en la lesión, el 50 % de la longitud y el 100 % del espesor del músculo gastrocnemio fueron seccionados. El PRP homólogo fue aplicado 24 horas después de la lesión. En el 7º día después de la lesión los animales fueron eutanasiados y las muestras fueran sometidas al ensayo mecánico para la medición de la tenacidad y análisis del colágeno, para realizar el cálculo de la relación entre los colágenos I y III. Los resultados demostraron una reducción significativa (p<0,05) en los valores de la relación entre los colágenos en todos los grupos lesionados en relación al grupo C. La tenacidad fue (p<0,05) reducida significativamente en los grupos lesionados en relación al grupo control, sin diferencia entre los tratados. En la lesión muscular hubo disminución de los valores de colágeno, aunque en los tratamientos se observó elevación de la cantidad de colágeno en la área lesionada, esta no tuvo efecto en la tenacidad de los músculos que fue disminuida en la lesión.

ABSTRACT In recent years, the technique of electrospinning has been used to develop a novel class of micro- and nanoscale materials based on fibrous structures. Several polymers, in particular elastomers, that have been implemented in this process rely on properties such as elasticity, flexibility, biocompatibility, and low cost. Herein, we describe for the first time the electrospinning of natural rubber fibers without polymeric matrix to obtain self-standing non-woven mats and oriented elastomeric fibers. The fibers average diameters were approximately 5.5 µm. Polyaniline (PAni) was deposited on the membrane surface in order to enhance the conductive properties making easy the charge transportation. We have obtained biocompatible and flexible fibrous materials using natural rubber, this research opens up possibilities of using micro and nanofibers of only-natural rubber in many applications including sensors preparation.

Abstract This study evaluated the genotoxicity, mutagenicity, antigenotoxicity, and antimutagenicity effects on biochemical parameters of oxidative stress of the Spondias dulcis bark ethanolic extract on mice. The extract was evaluated in the doses of 500, 1000, and 1500 mg/kg bw via gavage. To evaluate the protective effects of the extract, benzo[a]pyrene (B[a]P) and cyclophosphamide (CP) were chosen as DNA damage inducers. Genotoxicity and antigenotoxicity were evaluated by the comet assay. Cytotoxicity, mutagenicity, and antimutagenicity were evaluated by the micronucleus test in bone marrow and peripheral blood. The biochemical parameters of oxidative stress were evaluated by the quantification of catalase activity (CAT) and reduced glutathione (GSH) in total blood, liver and kidney, and malondialdehyde (MDA), in liver and kidney. No genotoxic, cytotoxic, or mutagenic effect was found on mice exposed to the extract. The extract depleted the number of damaged nucleoids in total blood and the number of micronucleus (MN) in both cell types. The extract was able to increase CAT activity and GSH levels and decrease MDA levels after treatment with B[a]P and CP. The results indicate that the S. dulcis extract has potential to be used as preventive compound against DNA damage caused by CP and B[a]P.

Colletotrichum gloeosporioides biomass was submitted to ethanolic extraction (78 ºC, 12 h) to remove low molecular weight compounds followed by hot aqueous extraction (100 ºC, 4 h, 4x) to obtain polysaccharides. Consecutive freezing/thawing treatments of the aqueous extract yielded a soluble fraction in cold water that was separated on five components (PI to PV) by gel exclusion chromatography on Sepharose CL-6B. The PIV was homogeneous on HPSEC/RID, with apparent MW of 2.8 x 104 g mol-1, Mw/Mn 1.17, 100% of total sugar. The PIV was composed by galactose (61%), glucose (34%) and mannose (5%). 1H and 13C NMR analysis mono- and two-dimensional, homo- (COSY) and heteronuclear (HSQC and HMBC) showed that PIV is a heteropolysacharide with a main chain constituted by β-D-galactofuranosidic units (1→5) and (1→6) linked with some of the β-D-galactofuranosidic (1→6) units substituted in O-3 by α-D-glucopiranosidic residues. Cytotoxic assays (MTT) indicated that the viability of CHO-K1 cells, when exposed to different heteropolysaccharide concentrations, did not show significant differences when compared to the viability of the negative control (CN), in the experimental times of 24 and 48 hours. These results suggest the possibility of new cytotoxic assays in other normal cell lines as well as in tumor cells.

RESUMO As blendas poliméricas obtidas com resíduos que antes eram chamados de lixos vêm crescendo como uma solução viável, permitindo melhorias nas propriedades mecânicas e como alternativas sustentáveis. Este trabalho relata os efeitos de misturas de polietileno de baixa densidade (PEBD) e borracha natural(NR), com cinzas de bagaço de cana-de-açúcar (CBCA) como carga, com e sem polietileno-enxertado com anidrido maleico (PE-g-MA) como agente de ligação. Os comportamentos dinâmico-mecânico e a análise de tensão-deformação foram estudados. Os materiais foram avaliados por calorimetria diferencial de varredura e observações morfológicas. Os resultados mostraram que a incorporação do PE-g-MA reduziu a deformação e melhorou o estresse e o módulo Young das misturas. Além disso, a presença de SCBA aumentou a dureza, mantendo a resistência à tração e o comportamento de alongamento do polímero. Os resultados demonstram o potencial uso da CBCA na mistura de elastômeros e termoplásticos, livres de agentes de vulcanização.

ABSTRACT The polymer blends obtained with residues that before were called wastes has been growing as a viable solution, allowing improvements in the mechanical properties and as sustainable alternative. This work reports the effects of blends of low-density polyethylene (LDPE) and natural rubber (NR), with sugar cane bagasse ash (SCBA) as filler, with and without polyethylene-graft-maleic anhydride (PE-g-MA) how coupling agent. The dynamic mechanical behavior and a stress-strain analysis were studied. The materials were further evaluated by differential scanning calorimetry and morphological observations. The results showed that incorporation of the PE-g-MA reduced the strain and improved the stress and the Young module of the mixtures. Moreover, the presence of SCBA increased the hardness while maintaining the tensile strength and the elongation behavior of the polymer. The results demonstrate the potential use of SCBA in the elastomer and thermoplastic mixture, free of vulcanization agents.

The chemical structure and composition of lignin and hemicellulose, as well as the distribution between inner and outer layers of fiber, can adversely affect bleaching operations or fiber-fiber bond on pulp and, consequently the papermaking process. Herein, we have implemented the fractionation and mechanical peeling techniques in order to identify the fines composition from eucalyptus cellulose as well as to verify the effect over xylan and lignin contents and the impact on oxygen delignification. Lignin and xylans in the material removed from the fiber surface (fines) were measured around to 7.6% and 12% of the composition, respectively. The lignin value is three times higher than the percentage measured to original fiber composition (without treatment). The residual xylans content on the pulp, after treatment of fines removal and peeling, was slightly reduced, around 3% for both treatments as well as fractionation and peeling methods decrease the oxygen delignification efficiency.

INTRODUÇÃO: A imobilização articular é uma técnica de tratamento frequentemente utilizada na ortopedia e, associada ao processo de senescência, promove alterações tanto na estrutura quanto na síntese e biomecânica do tecido cartilaginoso. OBJETIVO: Descrever os efeitos da imobilização, da remobilização livre e por meio de exercício físico sobre a cartilagem articular de ratos situados em duas faixas etárias. MÉTODOS: Trinta e nove ratos Wistar divididos em dois grupos etários, um grupo adulto (cinco meses de idade) e um idoso (15 meses de idade), subdivididos em: controle, imobilizado, remobilizado livre e remobilizado por meio de exercício físico. Os membros posteriores dos ratos foram imobilizados por sete dias. O protocolo de exercícios foi composto por cinco sessões diárias de natação, de 25 minutos cada. A cartilagem articular do quadril foi submetida à análise termogravimétrica, tendo sido avaliado seu conteúdo de água. RESULTADOS: Nos animais adultos a imobilização reduziu a quantidade de água presente no tecido cartilaginoso, e os protocolos de remobilização foram eficazes para restabelecer a condição inicial do tecido. Nos animais idosos não houve diferença significativa entre os grupos, porém o grupo idoso controle obteve resultado significantemente menor que o grupo adulto controle (X: 13,10 ± 5,24 vs 10,70 ± 1,95). CONCLUSÕES: A imobilização e o processo de senescência induzem a diminuição do conteúdo de água da cartilagem articular e os protocolos de remobilização foram eficientes para restabelecer esta propriedade apenas nos animais adultos.

INTRODUCTION: Joint immobilization is a technique often used in orthopedic treatment and, associated with the aging process, promotes changes in both the structure and synthesis and biomechanics of cartilage tissue. OBJECTIVE: To describe the effects of immobilization, free remobilization and remobilization by physical exercise over articular cartilage of rats of two age groups. METHODS: Thirty nine Wistar rats divided into two groups according to age, an adult group (five months old) and an elderly group (15 months old), and subdivided into: control, immobilized, free remobilized and remobilized by physical exercise. The pelvic limb of rats was immobilized for seven days. The exercise protocol consisted of 25 minutes swimming sessions, five sessions per day. The hip articular cartilage was subjected to thermogravimetric analysis, and the water content was evaluated. RESULTS: In adult animals immobilization reduced the water content of the articular cartilage, and the remobilization protocols were effective to restore the initial condition of the tissue. In elderly animals there were not significant differences among the groups, however the elderly control group obtained results significantly lower than the adult control group (X: 13.10 ± 5.24 vs 10.70 ± 1.95). CONCLUSIONS: Immobilization and the senescence process induce the decrease of water content of articular cartilage and remobilization protocols were effective to restoring this property only in adult animals.

INTRODUCCIÓN: La inmovilización articular es una técnica de tratamiento frecuentemente utilizada en ortopedia y asociada al proceso de senescencia, que promueve alteraciones tanto en la estructura como en la síntesis y la biomecánica del tejido cartilaginoso. OBJETIVO: Describir los efectos de la inmovilización, de la removilización libre y mediante el ejercicio físico sobre el cartílago articular de ratones de dos grupos de edad. MÉTODOS: Treinta y nueve ratones Wistar divididos en dos grupos de edad, un grupo adulto (cinco meses) y un grupo anciano (15 meses), y subdividos en control, inmovilizado, removilizado libre y removilizado a través de ejercicio físico. Los miembros posteriores de los ratones fueron inmovilizados durante un período de siete días. El protocolo de ejercicios fue compuesto por cinco sesiones diarias de natación, de 25 minutos cada una. El cartílago articular de la cadera fue sometido a análisis termogravimétrico, siendo evaluado su contenido de agua. RESULTADOS: En los animales adultos la inmovilización redujo la cantidad de agua presente en el tejido cartilaginoso, y los protocolos de removilización fueron eficaces para restablecer la condición inicial del tejido. En los animales ancianos no hubo diferencia significativa entre los grupos, aunque el grupo anciano control obtuvo resultado significativamente menor que el grupo adulto control (X: 13,10 ± 5,24 vs 10,70 ± 1,95). CONCLUSIONES: La inmovilización y el proceso de senescencia inducen la disminución en el contenido de agua de cartílago articular y los protocolos de removilización fueron eficientes para restablecer esta propiedad sólo en los animales adultos.

New flexible and transparent materials based on germanium sulfide were obtained using GeCl4 and 1,3-propanedithiol as precursors. These materials have transparency in the ultraviolet-visible (UV-Vis) spectral region (about 70%), thermal stability up to 200 °C and glass transition located at temperatures below 0 °C (-37 °C, -56 °C and -59 °C) as shown by differential scanning calorimetry (DSC) curves. Scanning electron microscopy (SEM) images showed that the polymer is homogeneous and presents formation of crystals in some regions of the surface. These polymers also exhibit Ge-S bonds in its structure, as can be observed through Fourier transform infrared (FTIR) (bands at 399, 401, 432 and 470 cm-1) and Raman (peaks at 361 and 430 cm-1) spectroscopies, and the diffraction patterns X-rays, which suggest the formation of a mixture of GeS2 and GeO2phases (also confirmed through energy-dispersive X-ray analysis). The coupled thermogravimetric analysis / Fourier transform infrared (TG/FTIR) technique was used to investigate the degradation of the sample. Taken together, the results of these characterizations suggest optical applications, and usability at low temperatures.

Waste recycling has been the subject of numerous scientific researches regarding the environmental care. This paper reports the redirecting of sugarcane bagasse ash (SBA) as new filler to natural rubber (NR/SBA). The NR/SBA composites were prepared using an opened cylinder mixer to incorporate the vulcanization agents and different proportions of residue (SBA). The ash contains about 70-90% of inorganic compounds, with silica (SiO2) being the main compound. The SBA incorporation improved the mechanical properties of the vulcanized rubber. Based on these results, a new use is proposed for the agro-industry organic waste to be implemented in the rubber vulcanization process, aimed at improving the rubber physical properties as well as decreasing the prices of natural rubber composites.

A presente pesquisa visou estudar os efeitos da remobilização por meio de exercício físico sobre o tecido ósseo de ratos adultos e idosos. Foram utilizados 80 ratos Wistar machos divididos em dois grupos, com idade de cinco meses para adultos e 15 meses para idosos; subdivididos em quatro subgrupos cada: grupo controle (G1 e G5), grupo imobilizado (G2 e G6), grupo remobilizado livre (G3 e G7), grupo remobilizado por meio de exercício físico (G4 e G8). Os grupos imobilizados foram eutanasiados logo após a retirada da imobilização gessada, que perdurou por 14 dias. Os grupos remobilizados livre permaneceram por sete dias em gaiolas coletivas após a retirada da imobilização, seguidos por eutanásia. Os grupos exercitados realizaram natação por 25 minutos/dia, durante sete dias, sendo posteriormente eutanasiados. Foi possível observar que os grupos remobilizados G3/G7 e G4/G8, tiveram um aumento da massa óssea em comparação ao G1/G5 e aos G2/G6. Com relação à análise mecânica, no grupo adulto houve significância estatística quando comparados a G2 e G3. A imobilização promoveu a redução da densidade mineral óssea e propriedades mecânicas, fato que ocorreu de forma inversa na remobilização.

This study aimed to analyze the effects of remobilization by means of physical exercise on bone tissue in rats and elderly adults. A total of 80 male Wistar rats were split into two groups, aged five months to 15 months for adults and elderly; each one was further split into 4 subgroups: control (G1 and G5), immobilized groups (G2 and G6), remobilized groups free (G3 and G7), remobilized groups through exercise (G4 and G8). The immobilized groups were euthanized immediately after removal of immobilization, which lasted for 14 days. The remobilized groups remained free for seven days in collective cages after removal immobilization, followed by euthanasia. The exercise groups underwent swimming for 25 min/day during 7 days and then were euthanized. It was observed that groups remobilized G3/G7 and G4/G8, had an increase in bone mass compared to the G1/G5 and G2/G6. With respect to mechanical analysis, in the adult group was statistically significance when compared G2 and G3. The immobilization process caused a reduction in the bone mineral density, likewise reducing their mechanical properties.