The aim of this study was to characterize the degree of conversion and the bond strength of experimental adhesive systems formulated with elastomeric monomers (Exothanes). Two-step self-etch adhesive systems were formulated, where the primer was constituted by HEMA, HEMA-P, water and ethanol, and the resin bonds were prepared mixing one type of Exothane (8, 9, 10, 24, or 32) (75 wt%) with TEGDMA (25 wt%). CQ, EDAB, and DPI were added as photo-initiation system. UDMA was used as control, so six different resin bonds were formulated at all. The adhesive system Clearfil SE Bond (CLSE) was used as a commercial control. The degree of conversion (DC) of each resin bond was evaluated in infrared spectroscopy (RT-FTIR, Shimadzu Prestige-21) using a diamond crystal (n = 3). The microshear bond strength (μSBS) test was performed using a universal testing machine (EMIC DL-500). While the DC data was analyzed by one-way ANOVA and Tukey (p < 0.05), the μSBS data was analyzed by Kruskal-Wallis test and Student-NewmanKeuls (p < 0.05). The resin bonds containing the Exothanes 8, 9, and 32 demonstrated DC values higher than 80%, differently to the other Exothane-based adhesives, which showed DC values close to 50%. UDMA and CLSE demonstrated lower DC than E 8 , E 9 , and E 32 (p < 0.001). The Exothane 24 resulted in the lowest DC value of the study (p < 0.001), although it was similar to the E 10 and UDMA adhesives (p > 0.05). Low μSBS results were seen for the Exothane-based materials. CLSE demonstrated significantly higher bond strength than the other materials (p < 0.001). UDMA has also presented low μSBS to the dentin substrate. It can be concluded that the Exothanes evaluated demonstrated satisfactory degree of conversion, with some of them reaching almost full conversion of monomers in polymer. However, considering the formulations investigated, they were not good bonding agents. So, they were not reliable options for composing the polymeric matrix of dental adhesive materials.
This study aimed to propose an eco-compatible strategy to mitigate the possible environmental contamination caused by tebuthiuron. Therefore, we screened potential tebuthiuron-degrading microorganisms from conventional (CS) and no-till (NTS) systems producing sugarcane. Then, they were bioprospected for their ability of decomposing the target-molecule at 2.48 mmol g−1 and 4.96 mmol g−1 into CO2 via respirometry. Integrating microbiota from CS and NTS into an advantageously synergistic bacterial pool produced the highest specific-growth rate of CO2 of 89.60 mg day−1, so outstripped the other inoculum. The bacterial CN-NTS framework notably stabilized the sigmoidal Gompertz curve on microbial degradation earliest and enabled the seeds of Lactucasativa to germinate healthiest throughout ecotoxicological bioassay for cross-validation. Our study is preliminary, but timely to provide knowledge of particular relevance to progress in the field's prominence in remediating terrestrial ecosystems where residual tebuthiuron can persist and contaminate. The analytical insights will act as an opening of solutions to develop high-throughput biotechnological strategies for environmental decontamination.
Synthetic fertilization can increase maize yields, but also cause environmental impacts, as well as increasing production costs and food security risks. Sun mushroom (Agaricus subrufescens) is an important Brazilian fungus used to generate large amounts of spent mushroom substrate. This residue can be used for maize fertilization, but little is known about its ideal application rates to reduce maize dependence on synthetic fertilizers. Therefore, this study aimed to evaluate the agronomic performance of a maize crop under different combinations of synthetic fertilizers and two different spent mushroom substrate doses. The experiment was carried out in pots and evaluated maize germinate and biometric parameters, as well as soil and leaf chemical characteristics. The results showed that residue application increased maize germination and Emergence Speed Index. Regarding the maize biometric parameters, height, stem diameter, shoot fresh and dry masses, and leaf area were superior for residue with synthetic fertilization at sowing only at higher doses. Moreover, residue with synthetic fertilization at sowing proved to be more relevant for maize growth according to canonical discriminant analysis. In terms of nutrients, the use of spent mushroom substrate increased significantly leaf P, K, and S levels and mainly K content in the soil, justifying non-application at maize topdressing.
A agroecologia ainda não forneceu instrumentos e critérios de análise para desenvolver estratégias locais ou regionais, onde os aspectos políticos e institucionais desempenhem um papel fundamental. Este artigo tem como objetivo contribuir para a superação dessas deficiências pela fundação teórica de como deveria ser a agroecologia envolvida na política. A agricultura familiar é o sujeito. É por meio dela que já se desenvolve a agroecologia, obtendo uma transição do modelo da agricultura tradicional, que traz a segurança alimentar para um modelo alternativo. Em primeiro lugar, argumenta-se que, como construção sócio ecológica, agroecossistemas é o produto de relações de poder. Em segundo lugar, mostra a estreita relação que a dinâmica dos agroecossistemas têm com a política e, portanto, o papel de destaque que ocupam no processo de transição agroecológica. É possível perceber a ausência de reflexões sobre a política da Agroecologia. Contudo, a amplitude dos movimentos agroecológicos e as experiências que são realizadas em diferentes níveis de ambos os governos locais e regionais aconselham o desenvolvimento por aspectos políticos da teoria agroecológica. Finalmente, tentada a um diagnóstico sob a situação do sistema global de alimentos, no qual o contexto das experiências agroecológicas deve ser desenvolvido. Palavras-Chave: Agroecologia, Sustentabilidade da Agricultura, Política Pública, Agroalimentar e Crise. ABSTRACTThe agroecology does not yet provide tools and analysis criteria to develop local and regional strategies, where political and institutional aspects play a key role. This article aims to contribute to overcoming these deficiencies by the theoretical foundation of how it should be Agroecology involved in politics. Family farming is the subject. It is through her that already develops agroecology, getting a transition from the model of traditional agriculture, which provides food security for an alternative model. First, it is argued that, as a socio-ecological construction, agro-ecosystems is the product of power relations. Secondly, it shows the close relationship that the dynamics of agro-ecosystems have with politics and therefore the important role they occupy in agroecological transition. Currently you can see that there is very little reflection on the politics of Agroecology. However, the range of agroecological movements and experiences that are held at different levels of both local and regional governments advise the development of political aspects of agro-ecological theory. Finally, a diagnosis attempted under the situation of global food system, in which the context of agroecological experiments must be developed.Keywords: Agroecology, Sustainable Agriculture, Public Policy, Agribusiness and Crisis.
It is well-known that bacteria and fungi play important roles in the relationships between mycelium growth and the formation of fruiting bodies. The sun mushroom, Agaricus subrufescens, was discovered in Brazil ca. 1960 and it has become known worldwide due to its medicinal and nutritional properties. This work evaluated the bacterial community present in mushroom-colonized compost extract (MCCE) prepared from cultivation of A. subrufescens, its dynamics with two different soaking times and the influence of the application of those extracts on the casing layer of a new compost block for A. subrufescens cultivation. MCCEs were prepared through initial submersion of the colonized compost for 1 h or 24 h in water followed by application on casing under semi-controlled conditions. Full-length 16S rRNA genes of 1 h and 24 h soaked MCCE were amplified and sequenced using nanopore technology. Proteobacteria, followed by Firmicutes and Planctomycetes, were found to be the most abundant phyla in both the 1 h and 24 h soaked MCCE. A total of 275 different bacterial species were classified from 1 h soaked MCCE samples and 166 species from 24 h soaked MCCE, indicating a decrease in the bacterial diversity with longer soaking time during the preparation of MCCE. The application of 24 h soaked MCCE provided increases of 25% in biological efficiency, 16% in precociousness, 53% in the number of mushrooms and 40% in mushroom weight compared to control. Further investigation is required to determine strategies to enhance the yield and quality of the agronomic traits in commercial mushroom cultivation.
Mushrooms are capable of bioconverting organic residues into food. Understanding the relationship between high-quality yields and substrate biomass from these residues is critical for mushroom farms when choosing new strains. The objective of this exploratory study was, therefore, to analyze whether exotic mushrooms, namely, Pleurotus eryngii, Flammulina velutipes, and Agrocybe aegerita, could biologically convert the substrate into edible mushrooms as effectively as Lentinula edodes (baseline). Five experiments were carried out. Biological efficiency, biodegradability coefficient, mass balance and chemical characterization of the substrate were evaluated. Strategically hydrating the sawdust enabled L. edodes to achieve the greatest biodegradability and biological efficiency of 0.5 and 94.2 kg dt−1, respectively. The values for L. edodes on wheat straw without hydration were 0.2 and 68.8 kg dt−1, respectively. From 1000 kg of fresh substrate, P. eryngii produced 150.1 kg of edible mushrooms, making it technically competitive with L. edodes on wheat straw (195.9 kg). Hence, P. eryngii was the most reliable option for scaling among the exotic mushrooms. The analytical insights from our study provide further knowledge to advance the field’s prominence in high-throughput mushroom-producing systems, particularly for exotic mushrooms.
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