43 documents found, page 1 of 5
Structural characterization of exopolysaccharides obtained from Porphyridium cr...
Cristofoli, Nathana L.; Lima, Alexandre R.; Costa, Ana M. Rosa da; Evtyugin, Dmitry; Silva, Carlos; Varela, João; Vieira, Margarida C.Microalgae produce and secrete large quantities of polysaccharides into the culture medium that is discarded when biomass is separated. The main objective of this study was to add value to the exhausted culture medium (ECM) of Porphyridium cruentum through the recovery of extracellular polysaccharides (EPS) by different extracting and purifying methods for the future biotechnological applications. The ECM was s...
Leaching efficiency and kinetics of the recovery of palladium and rhodium from ...
Nogueira, Carlos; Paiva, A. P.; Costa, M. Clara; Costa, Ana M. Rosa daABSTRACT: The recycling of scarce elements such as platinum-group metals is becoming crucial due to their growing importance in current and emerging applications. In this sense, the recovery of palladium and rhodium from a spent auto-catalyst by leaching in HCl/CuCl2 media was studied, aiming at assessing the kinetic performance as well as the influence of some processing factors, and the behaviour of contamina...
N,N '-dimethyl-N,N '-dicyclohexylsuccinamide: a novel molecule for the separati...
Costa, M. Clara; Assunção, Ana; Almeida, Ruben; Costa, Ana M. Rosa da; Nogueira, Carlos; Paiva, A. P.ABSTRACT: N,N'-dimethyl-N,N'-dicyclohexylsuccinamide (DMDCHSA) is investigated as a potential molecule for the liquid-liquid extraction of Pd(II) from chloride solutions for the first time. The effect of several parameters on Pd(II) extraction, such as the contact period between both phases, hydrochloric acid, extractant and hydrogen ion concentrations, is evaluated. Pd(II) extraction equilibrium is very fast (...
Synthesis and characterization of Locust Bean Gum derivatives and their applica...
Braz, Luis; Grenha, Ana; Corvo, Marta C.; Lourenço, João P.; Ferreira, Domingos; Sarmento, Bruno; Costa, Ana M. Rosa daThe development of LBG-based nanoparticles intending an application in oral immunization is presented. Nanoparticle production occurred by mild polyelectrolyte complexation, requiring the chemical modification of LBG. Three LBG derivatives were synthesized, namely a positively charged ammonium derivative (LBGA) and negatively charged sulfate (LBGS) and carboxylate (LBGC) derivatives. These were characterized by...
Efficiency of RAFT-synthesized PDMAEMA in gene transfer to the retina
Bitoque, Diogo; S, Simão; Oliveira, Ana V.; Machado, S.; Duran, Margarita R.; Lopes, Eduardo; Costa, Ana M. Rosa da; Silva, GabrielaGene therapy has long been heralded as the new hope to evolve from symptomatic care of genetic pathologies to a full cure. Recent successes in using gene therapy for treating several ocular and haematopoietic pathologies have shown the great potential of this approach that, in the early days, relied on the use of viral vectors, which were considered by many to be undesirable for human treatment. Therefore, ther...
A bridge between liquid-liquid extraction and the use of bacterial communities ...
Assunção, Ana; Matos, Ana; Costa, Ana M. Rosa da; Candeias, Antonio; Costa, Maria ClaraThe Platinum Group Metals (PGM) are rare in the Earth's crust and in the past years their use had a considerable expansion limiting their availability, which justifies PGM's high commercial value and demand. Therefore, PGM recovery from secondary sources is very important from both economic and environmental points of view. In recent years, several methods for PGM removal have been investigated. Our research gr...
Inhalable antitubercular therapy mediated by locust bean gum microparticles
Alves, Ana; Cavaco, Joana; Guerreiro, Filipa; Lourenço, J. P.; Costa, Ana M. Rosa da; Grenha, AnaTuberculosis remains a major global health problem and alternative therapeutic approaches are needed. Considering the high prevalence of lung tuberculosis (80% of cases), the pulmonary delivery of antitubercular drugs in a carrier system capable of reaching the alveoli, being recognised and phagocytosed by alveolar macrophages (mycobacterium hosts), would be a significant improvement to current oral drug regime...
Charged pullulan derivatives for the development of nanocarriers by polyelectro...
Dionísio, Marita; Braz, L.; Corvo, M.; Lourenço, J. P.; Grenha, Ana; Costa, Ana M. Rosa daPullulan, a neutral polysaccharide, was chemically modified in order to obtain two charged derivatives: reaction with SO3(.)DMF complex afforded a sulfate derivative (SP), while reaction with glycidyltrimethylammonium chloride gave a quaternary ammonium salt (AP). The presence of the charged groups was confirmed by FTIR. Assessment of the positions where the reaction took place was based on (1)H- and (13)C NMR ...
Effect of monomer organization on the behavior of PSS-PS micelles
Alves, Nuno G.; Rocha, Luciana S.; Moreira, José; Costa, Ana M. Rosa da; Pinheiro, J. P.Six copolymers of styrenesulfonate-styrene (SS-S) of varying molecular weights were prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization and proven to give rise to micelles in aqueous solution. Three are diblock copolymers (PSS-b-PS), while the other three have a random distribution of the two monomers, probably forming a gradient (PSS-co-PS). The latter ones form micelles of small...
Evaluation of cystamine-modified hyaluronic acid/chitosan polyplex as retinal g...
Oliveira, Ana V.; Marcelo, Adriana; Costa, Ana M. Rosa da; Silva, Gabriela A.A successful gene therapy approach can prevent or treat congenital and acquired diseases. However, there is still no ideal non-viral vector for gene delivery in a safe and timely manner. In this report the anionic polymer hyaluronic acid (HA) was investigated as a potential vector for gene therapy. Due to its intrinsic characteristics it constitutes an excellent candidate to deliver therapeutic genes, pending t...