Virgin and recycled polypropylene composites reinforced with sisal by-product

Foram estudadas as propriedades térmicas e mecânicas de compósitos de polipropileno, virgem e reciclado, reforçados com 30% em massa de fibras residuais de sisal, assim como o perfil de processamento e a morfologia da matriz polimérica. Para tanto, foram determinadas a resistência à tração, o módulo de Young, alongamento na ruptura, e energia de impacto. As amostras também foram caracterizadas por MEV, DMTA e TG. Para ambos os compósitos de polipropileno, virgem e reciclado, com a adição das fibras, o alongamento na ruptura mostrou uma queda significativa, enquanto que a resistência à tração não sofreu grandes variações. Houve um aumento significativo nos valores de tração na ruptura e de energia de impacto com a adição das fibras de sisal na matriz de polipropileno. As análises térmicas mostraram ligações secundárias, como as ligações polares, entre as fibras e a matriz, concordando com o comportamento mecânico dos compósitos. Constatou-se que a temperatura de transição vítrea não variou após a adição da fibra.The mechanical and thermal properties of virgin and recycled polypropylene composites reinforced with 30% by mass of residual sisal fibers were studied, in addition to an analysis of the extrusion process and morphology of the polymeric matrix. Tensile strength, Young's modulus, elongation at break, and impact energy were determined. The samples were also characterized by SEM, DMTA and TG analyses. Elongation at break of the composites presented a significant decrease, while the tensile strength was not affected significantly by addition of sisal fibers. A significant increase was observed in the tension of rupture and in the impact energy of the composite reinforced with sisal fiber. The thermal analyses indicated secondary interactions, such as polar interactions, between the fibers and the matrix, consistent with the mechanical behavior of the composites. The glass transition temperature has not changed after fiber addition.Universidade Federal de São Carlos - Departamento de Engenharia de MateriaisFinepCNP

Development and Validation of a Spectrophotometric Method in the UV-Vis Region to Evaluate the Interactions of Estrogens with Humic Substances in an Aqueous Environment

Natural and synthetic sex hormones are potent endocrine disruptors (EDs) that have been detected in aquatic environments on all continents. Studies show that humic substances (HS) are the main compounds capable of interacting with hormones, interfering in the bioavailability processes. In the present work, a methodology based on the colorimetric properties of the azo-compounds was developed and validated using diazotized sulfanilamide as a reagent to study the interactions with HS of estrogens: estrone (E1), 17β-estradiol (E2) and 17α-ethinylestradiol (EE2). As an alternative method to quantify hormones during interactions, ultraviolet-visible molecular absorption spectroscopy was employed. An analytical curve was constructed for concentrations ranging from 10.0 to 28.0 μg mL-1. The results were compatible with chromatography, also applied in this work. For the study of the interaction, samples of the hormone standard and HS solution were used under constant agitation. The reduction in the concentration of estrogens has been detected since the beginning of the process, with EE2 being the best result. In the aliquot removed from the system after 48 hours of agitation, 51.1% EE2 was removed in the presence of 10.0 μg mL-1 of the HS and 75.8% at 20 μg mL-1. Simulations can predict the behavior of hormones in natural aquatic environments rich in HS. DOI:  http://dx.doi.org/10.17807/orbital.v13i2.154

Genetic Markers Associated to Dyslipidemia in HIV-Infected Individuals on HAART

This study evaluated the impact of 9 single nucleotide polymorphisms (SNPs) in 6 candidate genes (APOB, APOA5, APOE, APOC3, SCAP, and LDLR) over dyslipidemia in HIV-infected patients on stable antiretroviral therapy (ART) with undetectable viral loads. Blood samples were collected from 614 patients at reference services in the cities of Porto Alegre, Pelotas, and Rio Grande in Brazil. The SNPs were genotyped by conventional polymerase chain reaction (PCR) and real-time PCR. The prevalence of dyslipidemia was particularly high among the protease inhibitors-treated patients (79%). APOE (rs429358 and rs7412) genotypes and APOA5 −1131T>C (rs662799) were associated with plasma triglycerides (TG) and low-density-lipoprotein cholesterol levels (LDL-C). The APOA5 −1131T>C (rs662799) and SCAP 2386A>G (rs12487736) polymorphisms were significantly associated with high-density-lipoprotein cholesterol levels. The mean values of the total cholesterol and LDL-C levels were associated with both the APOB SP Ins/Del (rs17240441) and APOB XbaI (rs693) polymorphisms. In conclusion, our data support the importance of genetic factors in the determination of lipid levels in HIV-infected individuals. Due to the relatively high number of carriers of these risk variants, studies to verify treatment implications of genotyping before HAART initiation may be advisable to guide the selection of an appropriate antiretroviral therapy regimen

Estabelecimento e multiplicação in vitro de Luehea divaricata Mart. & Zucc.

Luehea divaricata Mart. et  Zucc. (acoita-cavalo) of the Malvaceae family, is a forest-tree species that has suffered great anthropic disturbance during the last decades. This fact has contributed to the reduction of natural populations and, consequently, of its genetic variability. This justifies studies related to the propagation of the species. As a means of vegetative propagation, micropropagation is an alternative for the regeneration of plants with difficult natural regeneration and a strategy for species conservation. The objectives of this study were to determine the most efficient type of explant and growth medium for in vitro establishment and verify the influence of different concentrations of BAP cytokinin in the multiplication of nodal segments of Luehea divaricata. The seeds used were collected and stored by the Fundação Estadual de Pesquisa Agropecuária – FEPAGRO/Florestas (Agriculture and Cattle Research State Foundation – FEPAGRO/Forests), in Santa Maria, RS, Brazil, and the seedlings obtained in vitro were used as sources of the explants. In the selection of the explants and growth medium, the tips of stems and nodal segments grown in the MS and WMP nutritive media were tested. Different concentrations of BAP (0, 5, 10 and 15 mg L-1) were evaluated in the in vitro multiplication of the species. In the in vitro establishment of Luehea divaricata, both tips of stems and nodal segments can be used and also both growth media. To maximize the growth of the species, the WPM growth medium should be used due to its reduced cost. In the in vitro multiplication of the species, cytokinin BAP should not be added because, besides reducing the costs in the in vitro cultivation of Luehea divaricata, the best response for the majority of the characteristics evaluated was observed in the absence of this regulator,.O açoita-cavalo, Luehea divaricata Mart. & Zucc., pertencente à família Malvaceae, é uma espécie florestal que sofreu grande ação antrópica nas últimas décadas. Esse fato contribuiu muito para a redução das populações naturais e, consequentemente, de sua variabilidade genética, o que justifica a realização de estudos relacionados à propagação da espécie. Como forma de propagação vegetativa, a micropropagação torna-se uma opção para a regeneração de plantas que apresentam dificuldade de reprodução natural, além de ser uma estratégia para a conservação das espécies. O trabalho teve como objetivos determinar o tipo de explante e o meio de cultivo mais eficientes para o estabelecimento in vitro, além de verificar a influência de diferentes concentrações da citocinina BAP na multiplicação de segmentos nodais de açoita-cavalo. As sementes utilizadas foram coletadas e armazenadas pela Fundação Estadual de Pesquisa Agropecuária – FEPAGRO-Florestas em Santa Maria, RS e as plântulas obtidas in vitro foram utilizadas como fonte de explantes. Na seleção de explantes e meio de cultivo, foram testados segmentos apicais caulinares e segmentos nodais cultivados nos meios nutritivos MS e WPM. Diferentes concentrações de BAP (0, 5, 10 e 15 mg L-1) foram avaliadas na multiplicação in vitro de açoita-cavalo. No estabelecimento in vitro de açoita-cavalo podem-se empregar tanto segmentos apicais caulinares como segmentos nodais e ambos os meios de cultivo. Visando a maximizar o cultivo de açoita-cavalo, deve-se utilizar o meio de cultivo WPM, pelo custo reduzido. Na multiplicação in vitro de açoita-cavalo não deve ser adicionada a citocinina BAP, pois na ausência desse regulador se observa melhor resposta dos explantes para a maioria das características avaliadas, além de reduzir os custos no cultivo in vitro da espécie

Digital tools for supporting climate-informed agroecological transition in beef production in Brazil

KEY MESSAGES ◼ Despite many available digital tools in the digital ecosystem, many neglect smallholders’ ranching. Also, they focus solely on performance indicators, lacking climate-informed agroecological features. ◼ Mitigation features are included only by performance assessment tools, although only by half of them. ◼ Adaptation features in digital tools include mitigation recommendations, access to pest and disease information or early warning, and product diversification. ◼ Of the digital tools providing performance assessment (6 total), all include agroecological principles, three included adaptation, and all mitigation indicators on average per tool. ◼ Social inclusion and co-design features are related to data protection for farmers, direct farmer contributions (on the improvement of the digital tools), and safety measures, especially amongst women. ◼ Tools with socially inclusive communication features are limited. Most of the tools reviewed here have more than one way of engaging farm users (IVR, SMS, etc.), and allow the integration of other tools