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Projeto de investigação
Applied Molecular Biosciences Unit
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L-Phenylalanine derived tripodal vanadium complexes as catalysts for the asymmetric reductive coupling of benzaldehyde
Publication . Teixeira, Carlos M.; Adão, Pedro; Carvalho, M. Fernanda N.N.; Gomes, Clara S.B.; Pessoa, João Costa
Two tripodal vanadium complexes derived from modified L-phenylalanine were prepared and characterised.
Both compounds were tested for their catalytic activity in the reductive coupling of benzaldehyde. Overall, the
complexes are capable of catalysing the reductive coupling of benzaldehyde in the presence of metallic zinc as
co-reductant and alkylammonium or alkylpyridinium acetate salts in ethanol under mild aerobic conditions.
While benzyl alcohol is generally the major product, the yield of hydrobenzoin reaches ca. 38% under these
conditions. Enantioselectivities reach 39% and there is a preferential formation of the trans diastereoisomer of
hydrobenzoin. Attempts to study some aspects of the underlying mechanism were made. It was found that
metallic zinc is capable of reducing the complexes to VIII species, which are likely to be the active catalytic
species. The methodology described may set up a basis for the development of catalytic systems for the asymmetric synthesis of hydrobenzoins under mild conditions, not requiring chlorosilanes as electrophilic reagents for the regeneration of the catalyst.
Registered human trials addressing environmental and occupational toxicant exposures: Scoping review of immunological markers and protective strategies
Publication . Marques da Silva, Dorinda; Videira, Paula Alexandra; Lagoa, Ricardo
Exposure to pollution is a worldwide societal challenge participating in the etiology and progression of different
diseases. However, the scarce information hinders our understanding of the actual level of human exposure and its specific effects. Inadequate and excessive immune responses underlie diverse chronic diseases. Yet, it is unclear which and how toxicant exposures affect the immune system functions. There is a multiplicity of immunological outcomes and biomarkers being studied in human trials related to exposure to different toxicants but still without clear evidence of their value as biomarkers of exposure or effect. The main aim of this study was to collect scientific evidence and identify relevant immunological biomarkers used at the clinical level for toxicant exposures. We used the platform clinical trials.gov as a database tool. First, we performed a search combining research items related to toxicants and immunological parameters. The resulting117 clinical trials were examined for immune-related outcomes and specific biomarkers evaluated in subjects exposed to occupational and environmental toxicants. After categorization, relevant immunological outcomes and biomarkers were identified related to systemic and airway inflammation, modulation of immune cells, allergy and autoimmunity. In general, the immune markers related to inflammation are more frequently investigated for exposure to pollutants, namely IL-6, C-reactive protein (CRP) and nitric oxide (NO). Nevertheless, the data also indicated that prospective biomarkers of effect are gaining ground and a guiding representation of the established and novel biomarkers is suggested for upcoming trials. Finally, potential protective strategies to mitigate the adverse effects of specific toxicants are underlined for future studies.
Seasonal evaluation of Pholorotannin-Enriched extracts from brown macroalgae Fucus spiralis
Publication . Almeida, Belén; Barroso, Sonia; Ferreira, Ana S. D.; Adão, Pedro; Mendes, Susana; Gil, Maria M.
Fucus spiralis that was collected in the four seasons was submitted to an extraction with ethanol:water (crude extracts Et80), followed by a liquid–liquid fractionation with organic solvents (fraction He from n-hexane; aqueous fractions AQ1, AQ2, AQ3 and AQ4; ethyl acetate fraction EA), with the aim of obtaining phlorotannin-enriched extracts. All the extracts (Et80, He, AQ1, AQ2, AQ3, AQ4 and EA) that were obtained for the F. spiralis of the four seasons were evaluated for their antioxidant capacity and total phenolic compounds. The summer extracts presented the highest contents in polyphenols (TPC), as well as the highest ferric reducing antioxidant power (FRAP), when compared to the samples from the other seasons. The reductive percentage of the DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) compound was similar between the seasons. For all the seasons, the EA extract showed the highest polyphenol content (TPC), and the highest antioxidant capacity (highest ferric reducing power (FRAP) and lowest concentration needed to reduce 50% of the DPPH compound), which is in agreement with a phlorotannin-enriched fraction. This study revealed that the polyphenol content and antioxidant power of the F. spiralis extracts are influenced by the time of harvest, as well as by the solvents used for their extraction.
A Combined Vermifiltration-Hydroponic System for Swine Wastewater Treatment
Publication . Ispolnov, Kirill; Aires, Luis M. I.; Lourenço, Nídia D.; Vieira, Judite S.
Intensive swine farming causes strong local environmental impacts by generating effluents rich in solids, organic matter, nitrogen, phosphorus, and pathogenic bacteria. Insufficient treatment of hog farm effluents has been reported for common technologies, and vermifiltration is considered a promising treatment alternative that, however, requires additional processes to remove nitrate and phosphorus. This work aimed to study the use of vermifiltration with a downstream hydroponic culture to treat hog farm effluents. A treatment system comprising a vermifilter and a downstream deep-water culture hydroponic unit was built. The treated effluent was reused to dilute raw wastewater. Electrical conductivity, pH, and changes in BOD5, ammonia, nitrite, nitrate, phosphorus, and coliform bacteria were assessed. Plants were monitored throughout the experiment. Electrical conductivity increased due to vermifiltration; pH stayed within a neutral to mild alkaline range. Vermifiltration removed 83% of BOD5, 99% of ammonia and nitrite, and increased nitrate by 11%. Hydroponic treatment removed BOD5 (63%), ammonia (100%), nitrite (66%), nitrate (27%), and phosphorus (47% total and 44% dissolved) from vermifiltered water. Coliforms were reduced by vermifiltration but recovered in the hydroponic unit. Plants showed the ability to grow on vermi-filtered wastewater, although requiring nutrient supplementation. Vermifiltration combined with hydroponics is a promising treatment for swine wastewater, although optimization will be needed for a sustainable real-scale implementation.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
6817 - DCRRNI ID
Número da atribuição
UIDB/04378/2020