Characterisation of ultra- and nanofiltration membranes for predictive purposes - development of a model for hindered transport of uncharged solutes in asymmetric pores

Fundação para a Ciência e a Tecnologia (FCT

Degradation of mixtures of phenols using boron doped diamend electrodes for wastewater treatment

A model is proposed for describing the electrochemical oxidation of multicomponent mixtures of organic compounds, when significant mineralization (i.e., combustion to CO2) of the compounds occurs. This is known to be the case of the degradation of many organic compounds on boron doped diamond (BDD) and other new lectrocatalytic materials used as anodes. The proposed model predicts the variation of concentrations of each component present in the mixture, chemical oxygen demand (COD) and current efficiency as a function of time, under different rate control regimes (diffusive, kinetic and mixed) at constant current. Mass transfer coefficients of each component of the mixture, needed for the application of the model, were obtained from single solute experiments. Tests were conducted in a conventional three-electrode cell, using a commercial BDD electrode as anode. Good agreement between predicted and experimental results was generally obtained, though some deviations had been observed when the highest concentrations of the solutes were used, with concentrations decreasing faster than predicted. These deviations were found for both single- and multi-component systems, and can be explained by the occurrence of side reactions or the accumulation of intermediate compounds of the combustion mechanism

Plasmid DNA recovery from fermentation broths by a combined process of micro- and ultrafiltration : modeling and application

Microfiltration and ultrafiltration operations were used in tandem to isolate and purify a 6050 bp plasmid DNA (pDNA). To achieve primary isolation of the plasmid from fermentation broths, immediately after cell lysis, a 0.2 μm microfiltration membrane was selected for solid/liquid separation, which was performed in a diafiltration mode, as an alternative to centrifugation. Then to attain plasmid concentration and purification, an ultrafiltration membrane with a pore radius of 4.1 nm was selected. Permeation of pDNA and RNA in the two membrane steps was modeled using recently published mass transfer models applicable to the permeation of closed segmented chains and freely-jointed chains, respectively. The permeation of proteins and genomic DNA (gDNA) was also studied in these operations. The microfiltration operation allowed high plasmid and RNA permeation, as expected. It was observed that significant amounts of gDNA, previously precipitated during the cell lysis step, reappear in solution during the diafiltration step. The effect of the ionic strength on this apparent re-solubilization was investigated, by testing the addition of two different salts to the diafiltration buffer: CH3COOK and CaCl2. The results show that these salts can be used to control gDNA apparent re-solubilization. During the ultrafiltration operation high plasmid retention with low adsorption was obtained under low ionic strength conditions. The results also show that a significant removal proteins and the re-solubilized gDNA is achieved, as well as some purification in respect to low molecular weight RNA, since all these components permeate through the ultrafiltration membrane

Plasmid DNA/RNA separation by ultrafiltration: modeling and application study

RNA is one of the main soluble contaminants that needs to be separated from plasmid DNA (pDNA) during its recovery process from fermentation broths. Although significantly different in molecular size, pDNA and RNA are difficult to separate by membrane filtration due to the fact that both types of molecules are highly deformable and therefore suffer flow-induced elongation when permeating through porous membranes. The possibility of performing this separation by ultrafiltration is investigated here with the aid of a theoretical model describing the interactions between two electrically charged, flexible macromolecules that simultaneously permeate through a porous membrane. The results of the simulations, applied to pDNA and the different types of RNA present in cell lysates under typical process conditions, show that only by a careful choice of the membrane pore size and the imposed permeate flux one can achieve the required selectivity in this operation. Ultrafiltration tests using microfiltered lysates from the production of two different plasmids, pVAX1-LacZ (6050 bp) and pCAMBIA-1303 (12,361 bp), were carried out to check the validity of the theoretical predictions; the experimental results confirm these predictions and the idea that this technique can be used in practice for pDNA purification.Fundação para a Ciência e a Tecnologia (FCT

Determinação da Carga Alergénica (Ole e1) Presente no Ar Atmosférico na Região de Évora: Correlação com o conteúdo polínico de Olea

Introdução: Em Portugal, o pólen da oliveira (Olea europaea) constitui uma das fontes mais relevantes de aero-alergénios, sendo uma causa frequente de polinose na região Mediterrânica, onde o Ole e 1 é um alergeno major. Apesar de se julgar apenas associado aos grãos de pólen, desconhece-se a variabilidade inter-anual da carga alergénica do pólen e ainda existe alguma controvérsia sobre a forma como este aeroalergeno se distribui no ar atmosférico. Objectivo: Este trabalho teve como objectivos: i) determinar a fracção dos bioaerossóis mais rica em Ole e 1; ii) avaliar a correlação dos conteúdos diários de pólen e aeroalergeno no ar atmosférico; iii) avaliar variação anual da carga alergénica do pólen. Métodos: Os aeroalergenos foram captados utilizando um colector de impacto CHEMVOL equipado com dois filtros com capacidade para reter partículas de diferentes dimensões: PM>10µm e 10µm>PM>2,5µm. Após 24h os filtros foram retirados, a fracção proteica foi extraída e os alergenos quantificados por ELISA. Simultaneamente o pólen foi monitorizado pela tecnologia padrão utilizando um colector volumétrico Burkard 7-Day Recording Volumetric Spore Trap. Os colectores foram ambos colocados numa mesma plataforma a 17m de altura, e a ≈3-4m um do outro. Resultados: Entre 2009 e 2011, registou-se uma variação inter-anual quer do perfil quer da duração da época polínica (39, 47 e 45 dias, respectivamente). O conteúdo polínico total no ar atmosférico também foi variável no intervalo de 7240 a 12524 grãos/m3. Mais de 90% do alergeno foi encontrado na fracção de bioaerossóis de PM>10µm. O conteúdo em Ole e 1 foi directamente proporcional ao número de grãos de pólen no ar atmosférico, tendo-se encontrado uma correlação positiva entre os valores diários dos dois parâmetros. Comparando as épocas estudadas, os conteúdos totais de Ole e1 e de pólen não foram proporcionais, tendo-se observado que a carga alergénica por grão de pólen variou mais de 3x. Conclusões: Estes resultados sugerem que o Ole e 1 está preferencialmente associado aos grãos de pólen. Os conteúdos em pólen e Ole e 1 variaram inter-anualmente, tendo a carga alergénica dos grãos de pólen sido diferente. Este trabalho poderá assim contribuir para o desenvolvimento de um indicador que permita melhorar a previsão do risco de exposição a aeroalergenos. Agradecimentos: Este foi realizado no âmbito do projecto europeu HIALINE (Executive Agency for Health and Consumers, grant agreement No 2008 11 07)

Deposition of tin oxide, iridium and iridium oxide films by metal-organic chemical vapor deposition for electrochemical wastewater treatment

In this research, the specific electrodes were prepared by metal-organic chemical vapor deposition (MOCVD) in a hot-wall CVD reactor with the presence of O2 under reduced pressure. The Ir protective layer was deposited by using (Methylcyclopentadienyl) (1,5-cyclooctadiene) iridium (I), (MeCp)Ir(COD), as precursor. Tetraethyltin (TET) was used as precursor for the deposition of SnO2 active layer. The optimum condition for Ir film deposition was at 300 °C, 125 of O2/(MeCp)Ir(COD) molar ratio and 12 Torr of total pressure. While that of SnO2 active layer was at 380 °C, 1200 of O2/TET molar ratio and 15 Torr of total pressure. The prepared SnO2/Ir/Ti electrodes were tested for anodic oxidation of organic pollutant in a simple three-electrode electrochemical reactor using oxalic acid as model solution. The electrochemical experiments indicate that more than 80% of organic pollutant was removed after 2.1 Ah/L of charge has been applied. The kinetic investigation gives a two-step process for organic pollutant degradation, the kinetic was zero-order and first-order with respect to TOC of model solution for high and low TOC concentrations, respectively

Pediatric Laparoscopic Pieloplasty

Introdução: A obstrução da junção pielo-ureteral (OJPU) é a causa congénita mais comum de uropatia obstrutiva na criança. O objectivo deste trabalho é documentar a experiência desta Unidade de Urologia Pediátrica relativamente às primeiras 20 pieloplastias realizadas por via laparoscópica. Material e Métodos: Estudo retrospectivo em que foram incluídos vinte doentes com o diagnóstico de OJPU submetidas a pieloplastia por via laparoscópica, por um único cirurgião, no nosso Hospital, no período compreendido entre Novembro de 2010 e Dezembro 2014, tendo completado pelo menos um ano de seguimento. O sucesso do procedimento foi definido como ausência de conversão, resolução dos sintomas e melhoria dos critérios imagiológicos. Resultados: A mediana da idade à data da cirurgia foi de 9,5 anos (variando entre os 10 meses e os 17 anos). Constatou-se a existência de obstrução intrínseca em sete casos, obstrução extrínseca em 12 casos, sendo que num caso se verificaram as duas situações. O tempo operatório mediano foi de 235 minutos (variando entre 165 e 275 minutos), tendo havido necessidade de conversão para abordagem laparotómica em dois casos (10%). O tempo mediano de internamento foi de dois dias (variando entre 2 e 5 dias). Em quatro casos (20%) registaram-se complicações pós-operatórias precoces e houve necessidade de re-intervenção em dois casos (10%) durante o seguimento. O tempo mediano de seguimento foi de 33 meses (variando entre 12 e 60 meses). No seguimento, todos excepto dois doentes estavam assintomáticos. Constatou-se melhoria imagiológica da hidronefrose em todos os doentes excepto em um, apesar de não apresentar padrão obstrutivo no renograma. Conclusão: Os nossos resultados são consistentes com os da literatura publicada, com taxas de sucesso comparáveis com a abordagem por via laparotómica e com as vantagens da cirurgia minimamente invasiva.info:eu-repo/semantics/publishedVersio

Extracellular vesicles from pancreatic cancer stem cells lead an intratumor communication network (EVNet) to fuel tumour progression

© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ. http://creativecommons.org/licenses/by-nc/4.0/This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.Objective: Intratumor heterogeneity drives cancer progression and therapy resistance. However, it has yet to be determined whether and how subpopulations of cancer cells interact and how this interaction affects the tumour. Design: We have studied the spontaneous flow of extracellular vesicles (EVs) between subpopulations of cancer cells: cancer stem cells (CSC) and non-stem cancer cells (NSCC). To determine the biological significance of the most frequent communication route, we used pancreatic ductal adenocarcinoma (PDAC) orthotopic models, patient-derived xenografts (PDXs) and genetically engineered mouse models (GEMMs). Results: We demonstrate that PDAC tumours establish an organised communication network between subpopulations of cancer cells using EVs called the EVNet). The EVNet is plastic and reshapes in response to its environment. Communication within the EVNet occurs preferentially from CSC to NSCC. Inhibition of this communication route by impairing Rab27a function in orthotopic xenographs, GEMMs and PDXs is sufficient to hamper tumour growth and phenocopies the inhibition of communication in the whole tumour. Mechanistically, we provide evidence that CSC EVs use agrin protein to promote Yes1 associated transcriptional regulator (YAP) activation via LDL receptor related protein 4 (LRP-4). Ex vivo treatment of PDXs with antiagrin significantly impairs proliferation and decreases the levels of activated YAP.Patients with high levels of agrin and low inactive YAP show worse disease-free survival. In addition, patients with a higher number of circulating agrin+ EVs show a significant increased risk of disease progression. Conclusion: PDAC tumours establish a cooperation network mediated by EVs that is led by CSC and agrin, which allows tumours to adapt and thrive. Targeting agrin could make targeted therapy possible for patients with PDAC and has a significant impact on CSC that feeds the tumour and is at the centre of therapy resistance.The work was supported by NORTE-01–0145-FEDER-000029, Norte Portugal Regional Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund and national funds through FCT—Foundation for Science and Technology POCI-01–0145-FEDER-32189. Programa Operacional Regional do Norte and co-financed by European Regional Development Fund under the project "The Porto Comprehensive Cancer Center" with the reference NORTE-01-0145-FEDER-072678 - Consórcio PORTO.CCC – Porto.Comprehensive Cancer Center. CFR is supported by FCT (SFRH/BD/131461/2017), NB by (SFRH/BD/130801/2017), IB by FCT (SFRH/BD/144854/2019), and BA by FCT (PD/BD/135546/2018). DG’s contribution was supported by the NCI (R21 CA179907). We acknowledge the support of the i3S Scientific Platforms: Translational Cytometry, Animal Facility, Bioimaging and Histology and Electron Microscopy are members of the national infrastructure PPBI - Portuguese Platform of Bioimaging (PPBI-POCI-01–0145-FEDER-022122). Proteomics was performed at the Proteomics Facility of The Spanish National Center for Biotechnology (CNB-CSIC), ProteoRed, PRB3-ISCIII, supported by grant PT17/0019.info:eu-repo/semantics/publishedVersio

Nanofiltration separation of polyvalent and monovalent anions in desalination brines

This work, as part of a global membrane process for the recovery of alkali and acids from reverse osmosis (RO) desalination brines, focuses on the nanofiltration (NF) separation of polyvalent and monovalent anions, more specifically sulfate and chloride. This pretreatment stage plays a key role in the whole recovery process. Working with model brines simulating the concentration of RO concentrates, 0.2–1.2 M chloride concentration and 0.1 M sulfate concentration, the experimental performance and modeling of the NF separation is reported. The study has been carried out with the NF270 (Dow Filmtec) membrane. The effect of operating pressure (500–2000 kPa), ionic strength (0.4–1.3 M) and chloride initial concentration (0.2–1.2 M) on the membrane separation capacity has been investigated. Finally, the Donnan Steric Pore Model (DSPM) together with experimentally determined parameters, effective pore radius (rp), thickness of the membrane effective layer (d) and effective membrane charge density (Xd), was proved accurate enough to satisfactorily describe the experimental results. In this work we provide for the first time the analysis of partitioning effects and transport mechanism in the NF separation of sulfate and chloride anions in concentrations that simulate those found in RO desalination brines.This work has been financially supported by projects CTQ2008-0690, ENE2010-15585 and CTM2011-23912 (co-financed by ERDF Funds).The authors would like to acknowledge SADYT, S.A. for providing assistance for this work

Mechanisms governing the selectivity of NF membranes during the concentration of clavulanic acid

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