Browsing by Author "Silva, Andreia"
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- Adsorption of Fluoxetine and Venlafaxine onto the Marine Seaweed Bifurcaria bifurcataPublication . Silva, Andreia; Stawiński, Wojciech; Romacho, Juan; Santos, Lúcia H.M.L.M.; Figueiredo, Sónia; Freitas, Olga; Delerue-Matos, CristinaMarine macroalga Bifurcaria bifurcata was investigated as sorbent for two environmental emerging pollutants, the pharmaceuticals venlafaxine (VLF) and fluoxetine (FLX), from aqueous solutions, both in mono and bicomponent batch systems. The alga was characterized by means of IR spectroscopy, allowing to identify the most important groups for biosorption, carboxylic, sulfonic and hidroxile. The point of zero charge was determined, being 6.4. Adsorption of FLX follows a pseudo first order kinetics and kinetic constants are higher for FLX than for VLF. Its adsorption better represented by the pseudo second order model. For both pharmaceuticals, the equilibrium was reached within *100 min. Adsorption studies reveal that the process was more efficient at lower pH range and followed the Langmuir–Freundlich’s model for VLF and Langmuir’s model for FLX. Maximum adsorption capacities reached a level of 12 – 3 and 22 – 4 lmol/g for VLF and FLX, respectively, in the mono-component system. The difference was attributed to the presence of various functional groups of varying polarity within the adsorbates’ molecules that affected their interactions with the adsorbent surface. The Langmuir–Freundlich’s extended model was applied to the adsorption data of the bicomponent system and no changes in the maximum adsorption capacities were found (14 – 2 and 20 – 3 lmol/g for VLF and FLX, respectively), there is no evidence of competition between the adsorbates.
- Application of vermiculite-derived sustainable adsorbents for removal of venlafaxinePublication . Silva, Andreia; Martinho, Sílvia; Stawiński, Wojciech; Węgrzyn, Agnieszka; Figueiredo, Sónia; Santos, Lúcia H. M. L. M.; Freitas, OlgaRemoval of emerging pollutants, such as pharmaceuticals, from wastewater is a challenge. Adsorption is a simple and efficient process that can be applied. Clays, which are natural and low-cost materials, have been investigated as adsorbent. In this work, raw vermiculite and its three modified forms (expanded, base, and acid/base treated) were tested for removal of a widely used antidepressant, venlafaxine. Adsorption kinetics followed Elovich's model for raw vermiculite while the pseudo-2nd order model was a better fit in the case of other materials. Equilibrium followed Langmuir's model for the raw and the acid/base-treated vermiculite, while Redlich-Peterson's model fitted better the expanded and the base-treated materials. The adsorption capacity of vermiculite was significantly influenced by the changes in the physical and chemical properties of the materials caused by the treatments. The base-treated, raw, and expanded vermiculites showed lower maximum adsorption capacities (i.e., 6.3 ± 0.5, 5.8 ± 0.7, 3.9 ± 0.2 mg g-1, respectively) than the acid/base-treated material (33 ± 4 mg g-1). The acid/base-treated vermiculite exhibited good properties as a potential adsorbent for tertiary treatment of wastewater in treatment plants, in particular for cationic species as venlafaxine due to facilitation of diffusion of the species to the interlayer gallery upon such treatment. Graphical abstract ᅟ.
- Comparação e otimização de métodos de extração de DNA de células cervicais colhidas em ThinPrep® PreservCyt™Publication . Silva, Andreia; Salta, S.; Henrique, R.; Jerónimo, C.O cancro do colo do útero é o nono cancro mais incidente nas mulheres em Portugal. O rastreio desta neoplasia tem evoluído desde a citologia convencional até à deteção do Vírus do Papiloma Humano em colpocitologia cervico-vaginal em meio líquido. Atualmente, novos marcadores biomoleculares, como alterações na metilação do ácido desoxirribonucleico (DNA), têm sido estudados como meio de triagem de mulheres infetadas pelo Vírus do Papiloma Humano. O objetivo deste estudo foi otimizar e comparar três métodos de extração de DNA para análise da metilação. Extraiu-se DNA de dezasseis amostras de colpocitologia, colhidas em ThinPrep® PreservCyt™, através do método fenol-clorofórmio e dos kits QIAamp® MinElute™ Media (QIAGEN, Hilden) e Blood DNA Isolation Mini Kit(Norgen Biotek, Ontario). Após quantificação, o DNA foi modificado por bissulfito de sódio e amplificado por Reação em Cadeia da Polimerase Quantitativa de Metilação Específica para o gene β-Actina. Os valores médios de Cycle threshold (Ct) foram avaliados.O método fenol-clorofórmio teve maior input, e consequentemente conferiu maior quantidade de DNA. Com 15mL de amostra obteve-se 13500ng pelo método fenol-clorofórmio enquanto com 2mL de amostra se obteve 8940ng do kit QIAamp® MinElute™ Media e 927ng do Blood DNA Isolation Mini Kit. Contudo, os kits apresentaram maior eficácia de extração, bem como maior rapidez e facilidade de execução. Não se verificaram diferenças significativas entre os valores médios de Ct de cada método de extração nem entre amostrasarmazenadas durante dez ou catorze meses. Concluindo, os três métodos permitiram obter DNA para amplificação mas a otimização dos kits de extração revelou-se ser a opção mais vantajosa.
- Discrepância cito-histológica: estudo de caso em citologia do canal analPublication . Silva, Andreia; Teixeira, Catarina; Seabra, Rosária; Freitas, Cristina; Ribeiro, MariaO cancro anal é raro mas a sua incidência tem vindo a aumentar na população, essencialmente em indivíduos HIV positivo, nos quais a infeção por HPV tem maior persistência. A infeção por HPV de alto risco está associada à presença e progressão de lesões displásicas, precursoras de cancro anal. Por esta razão, os indivíduos HIV positivos são considerados um grupo de risco, devendo ser encaminhados para realização de rastreio de lesões do canal anal. No presente artigo, é relatado o caso clínico de um homem de 53 anos, HIV positivo, com diagnósticos cito-histológicos discrepantes em que a avaliação citológica resultou na atribuição de diagnósticos de lesões de grau superior comparativamente às da histologia. Este estudo de caso pretende alertar para a importância da realização de rastreios citológicos do canal anal, principalmente em indivíduos pertencentes a grupos de risco, e da avaliação de resultados discrepantes entre a citologia e a histologia.
- Fluoxetine and Nutrients Removal from Aqueous Solutions by PhycoremediationPublication . Silva, Andreia; Fernandes, Diana F.; Figueiredo, Sónia; Freitas, Olga; Delerue-Matos, CristinaThe tertiary treatment using microalgae offers an attractive alternative to the removal of low but relevant concentrations of pharmaceuticals from domestic wastewaters. The removal of fluoxetine from aqueous solutions by living and non-living (lyophilized) Chlorella vulgaris was assessed. The determination of the pH at the point of zero charge, Fourier transmittance infrared analysis, and scanning electron microscopy were performed to characterize the microalgae biomass. Kinetic and equilibrium experiments were performed. The pseudo-second-order model described the kinetics of fluoxetine. The corresponding kinetic constants indicated that biosorption was faster onto non-living biomass than onto living biomass. The equilibrium results showed that the systems followed the Langmuir isotherm model. The maximum capacity of living microalgae (1.9 ± 0.1 mg·g−1) was slightly higher than the non-living microalgae (1.6 ± 0.2 mg·g−1). Living Chlorella vulgaris, free and immobilized in calcium-alginate, were also used to remove fluoxetine and nutrients (nitrogen and phosphorus) from treated municipal wastewater in a batch system. In both experiments, fluoxetine was completely removed within six days. The total phosphorus (TP) and total nitrogen (TN) removal efficiencies achieved for free and immobilized cells were, null and 65.0 ± 0.1%, and 86.2 ± 0.1% and 81.8 ± 3.1, respectively
- Fluoxetine Removal from Aqueous Solutions Using a Lignocellulosic Substrate Colonized by the White-Rot Fungus Pleurotus ostreatusPublication . Silva, Andreia; Sousa, Juliana; Hultberg, Malin; Figueiredo, Sónia; Freitas, Olga; Delerue-Matos, CristinaOne of the main challenges in both the design of new wastewater treatment plants and the expansion and improvement of existing ones is the removal of emerging pollutants. Therefore, the search for economic and sustainable treatments is needed to enhance the removal of pharmaceuticals. The potential of a lignocellulosic substrate colonized by Pleurotus ostreatus, a waste from mushroom production, to remove fluoxetine from aqueous solutions was studied. Batch assays were performed to remove 600 µg∙L−1 fluoxetine from aqueous solutions using the colonized mushroom substrate (CMS) and crude enzyme extracts. The removal efficiencies achieved were, respectively, ≥83.1% and 19.6% in 10 min. Batch assays with sterilized CMS and 1-aminobenzotriazole (to inhibit cytochrome P450 enzymes) showed that the higher removal efficiencies achieved in the CMS assays may be attributed to the synergistic contribution of biosorption onto the CMS and lignin modifying enzymes activity, namely laccase activity. A column assay was performed with the CMS, fed with 750 µg∙L−1 fluoxetine aqueous solution. The removal efficiency was 100% during 30 min, decreasing to a final value of 70% after 8 h of operation. The results suggested that CMS can be a promising eco-friendly alternative to remove fluoxetine from aqueous solutions
- Green Microalgae Scenedesmus Obliquus Utilization for the Adsorptive Removal of Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) from Water SamplesPublication . Silva, Andreia; Coimbra, Ricardo N.; Escapa, Carla; Figueiredo, Sónia; Freitas, Olga; Otero, MartaIn view of the valorisation of the green microalga Scenedesmus obliquus biomass, it was used for the biosorption of two nonsteroidal anti-inflammatory drugs, namely salicylic acid and ibuprofen, from water. Microalgae biomass was characterized, namely by the determination of the point of zero charge (pHPZC), by Fourier transform infrared (FT-IR) analysis, simultaneous thermal analysis (STA) and scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS). Kinetic and equilibrium batch experiments were carried out and results were found to fit the pseudo-second order equation and the Langmuir isotherm model, respectively. The Langmuir maximum capacity determined for salicylic acid (63 mg g−1) was larger than for ibuprofen (12 mg g−1), which was also verified for a commercial activated carbon used as reference (with capacities of 250 and 147 mg g−1, respectively). For both pharmaceuticals, the determination of thermodynamic parameters allowed us to infer that adsorption onto microalgae biomass was spontaneous, favourable and exothermic. Furthermore, based on the biomass characterization after adsorption and energy associated with the process, it was deduced that the removal of salicylic acid and ibuprofen by Scenedesmus obliquus biomass occurred by physical interaction.
- Influence of long-term wearing of unstable shoes on compensatory control of posture: An electromyography-based analysisPublication . Pinheiro De Sousa, Andreia Sofia; Silva, Andreia; Macedo, Rui; Santos, Rubim; Tavares, João ManuelThis study investigated the influence of long-term wearing of unstable shoes (WUS) on compensatory postural adjustments (CPA) to an external perturbation. Participants were divided into two groups: one wore unstable shoes while the other wore conventional shoes for 8 weeks. The ground reaction force signal was used to calculate the anterior– posterior (AP) displacement of the centre of pressure (CoP) and the electromyographic signal of gastrocnemius medialis (GM), tibialis anterior (TA), rectus femoris (RF) and biceps femoris (BF) muscles was used to assess individual muscle activity, antagonist co-activation and reciprocal activation at the joint (TA/GM and RF/(BF + GM) pairs) and muscle group levels (ventral (TA + RF)/dorsal (GM + BF) pair) within time intervals typical for CPA. The electromyographic signal was also used to assess muscle latency. The variables described were evaluated before and after the 8-week period while wearing the unstable shoes and barefoot. Long-term WUS led to: an increase of BF activity in both conditions (barefoot and wearing the unstable shoes); a decrease of GM activity; an increase of antagonist co-activation and a decrease of reciprocal activation level at the TA/GM and ventral/dorsal pairs in the unstable shoe condition. Additionally, WUS led to a decrease in CoP displacement. However, no differences were observed in muscle onset and offset. Results suggest that the prolonged use of unstable shoes leads to increased ankle and muscle groups’ antagonist co-activation levels and higher performance by the postural control system.
- Influence of prolonged wearing of unstable shoes on upright standing postural controlPublication . Pinheiro De Sousa, Andreia Sofia; Macedo, Rui; Santos, Rubim; Sousa, Filipa; Silva, Andreia; Tavares, João M. R. S.To study the influence of prolonged wearing of unstable shoes on standing postural control in prolonged standing workers. The participants were divided into two groups: one wore unstable shoes while the other wore conventional shoes for 8 weeks. Stabilometry parameters related to centre of pressure (CoP), rambling (RM) and trembling (TR) as well as the total agonist/antagonist muscle activity, antagonist co-activation and reciprocal activation were evaluated during upright standing, before and after the 8 week period. In both moments, the subjects were evaluated wearing the unstable shoes and in barefoot. The unstable shoe condition presented increased CoP displacement related variables and decreased co-activation command compared to barefoot before and after the intervention. The prolonged wearing of unstable shoes led to: (1) reduction of medial-lateral CoP root mean square and area; (2) decreased anteroposterior RM displacement; (3) increased anteroposterior RM mean velocity and mediolateral RM displacement; (4) decreased anteroposterior TR RMS; and (5) increased thigh antagonist co-activation in the unstable shoe condition. The unstable shoe condition is associated to a higher destabilizing effect that leads to a selection of more efficient and accurate postural commands compared to barefoot. Prolonged wearing of unstable shoes provides increased effectiveness and performance of the postural control system, while wearing of unstable shoes in upright standing, that are reflected by changes in CoP related variables and by a reorganization of postural control commands.
- The Use of Algae and Fungi for Removal of Pharmaceuticals by Bioremediation and Biosorption Processes: A ReviewPublication . Silva, Andreia; Delerue-Matos, Cristina; Figueiredo, Sónia; Freitas, OlgaThe occurrence and fate of pharmaceuticals in the aquatic environment is recognized as one of the emerging issues in environmental chemistry. Conventional wastewater treatment plants (WWTPs) are not designed to remove pharmaceuticals (and their metabolites) from domestic wastewaters. The treatability of pharmaceutical compounds in WWTPs varies considerably depending on the type of compound since their biodegradability can differ significantly. As a consequence, they may reach the aquatic environment, directly or by leaching of the sludge produced by these facilities. Currently, the technologies under research for the removal of pharmaceuticals, namely membrane technologies and advanced oxidation processes, have high operation costs related to energy and chemical consumption. When chemical reactions are involved, other aspects to consider include the formation of harmful reaction by-products and the management of the toxic sludge produced. Research is needed in order to develop economic and sustainable treatment processes, such as bioremediation and biosorption. The use of low-cost materials, such as biological matrices (e.g., algae and fungi), has advantages such as low capital investment, easy operation, low operation costs, and the non-formation of degradation by-products. An extensive review of existing research on this subject is presented.