Reduction and construction of Poisson quasi-Nijenhuis manifolds with background

We extend the Falceto-Zambon version of Marsden-Ratiu Poisson reduction to Poisson quasi-Nijenhuis structures with background on manifolds. We define gauge transformations of Poisson quasi-Nijenhuis structures with background, study some of their properties and show that they are compatible with reduction procedure. We use gauge transformations to construct Poisson quasi-Nijenhuis structures with background.Comment: to appear in IJGMM

Characterization of the wave bioreactor: residence time distribution

The high dose requirements of biopharmaceutics have led to the development of mammalian cell culture technologies to increase biomanufacturing capacity. Among them, disposable bioreactors are attracting attention, particularly the Wave bioreactor. This system induces an undulation movement to the culture, ensuring good mixing and oxygen transfer without shear damage, and requires no cleaning/sterilization, providing simpler operation and no cross-contamination. However, this new reactor still needs further characterization. In this sense, the residence time distribution (RTD) was evaluated, allowing the characterization of the mixing/flow and the comparison with ideal models and a commercial stirred tank reactor (STR). RTD was determined using methylene blue with a pulse input methodology, at three mammalian culture flow rates: low (L: 3.3x10-5 m3/h), intermediate (I: 7.9x10-5 m3/h), and high (H: 1.25x10-4 m3/h). Samples were taken and absorbance read at 660 nm. Results show that Wave behaviour approximates the ideal and experimental STR at flow L, but deviates from ideal models at flows I and H. The comparison of average residence time (tr) with time of passage (τ) provides a possible explanation for this non-ideality. For STR at all flows and Wave at flow H, tr was lower than τ, indicating dead zones inside the reactor. For Wave at flows L and I, tr was higher than τ, indicating short-circuiting. In conclusion, the choice of flow rate will strongly influence the behaviour of the Wave bioreactor. The use of a low flow seems to be a choice that provides behaviour closer to the ideal continuous STR model

Otimização de uma metodologia para a determinação da composição em ácidos gordos da membrana de eritrócitos por GC-FID

Atualmente é consensual a ideia de que a composição lipídica tem influência determinante no risco de algumas doenças crónicas. A ingestão de grandes quantidades de ácidos gordos saturados e ácidos gordos trans tem sido associado a dislipidémias e aumento do risco de doenças cardiovasculares, enquanto que o consumo de ácidos gordos polinsaturados, especialmente ómega-3, tem sido associado a diversos benefícios para a saúde. Pelo facto de os eritrócitos apresentarem um elevado tempo de vida, tem sido sugerido por diversos autores que o perfil em ácidos gordos das membranas destas células poderá ser usado não apenas como um biomarcador que reflita a ingestão de macronutrientes da dieta, mas também como um biomarcador associado a diferentes patologias como diabetes, cancro e doenças cardiovasculares. Por este motivo, o presente trabalho teve como objetivo desenvolver um método simples e rápido para a identificação e quantificação de ácidos gordos presentes na membrana de eritrócitos utilizando cromatografia gasosa com detetor de ionização em chama (GC-FID). Para tal, foram obtidas amostras de sangue, a partir das quais se procedeu ao isolamento da fração contendo eritrócitos. Seguidamente foram testados diferentes protocolos para a preparação da amostra a ser analisada por GC-FID, incluindo um método clássico modificado (método de Folch) e quatro métodos rápidos, para os quais a realização da extração lipídica e reação de derivatização decorrem num passo único. No que concerne aos métodos rápidos, foi avaliada a influência de diferentes parâmetros, nomeadamente diferentes tempos de metilação e a realização, ou não, de reação de saponificação. Com base nos resultados obtidos, selecionou-se o método rápido com saponificação e com tempo de metilação de 60 minutos como sendo o mais adequado para o objetivo pretendido, permitindo obter um maior número de ácidos gordos identificados. Agradecimentos: Ao apoio financeiro concedido pela FCT no âmbito dos projetos PTDC/SAU-ENB/116929/2010 e EXPL/EMS-SIS/2215/2013, COMPETE, QREN e União Europeia (FEDER).info:eu-repo/semantics/publishedVersio

Development of a methodology using GC-FID for the quantitativo analysis of fatty acids from red blood cells

In the last years, there has been an increasing interest in evaluating possible relations between fatty acid patterns and the risk for chronic diseases. Currently, it is generally accepted that higher intakes of saturated and trans fatty acids are related with dyslipidemia and increased risk for cardiovascular diseases, while the consumption of polyunsaturated fatty acids, especially omega-3, has been positively associated with several health benefits. So far, most studies concerning the analysis of blood fatty acids (FA) composition have been performed using plasma or serum, with red blood cells (RBCs) usually being discarded [l]. However, because of the long half-life (120 days) of these cells, the FA profile of RBCs membrane may reflect longer-term markers of nutritional intake compared with plasma or urine [l].This work received financiai support from the European Union (FEDER funds through COMPETE) and National Funds (FCT, Fundação para a Ciência e Tecnologia) through project projetos PTDC/SAU-ENB/116929/2010 andEXPL/EMS-SIS/2215/2013info:eu-repo/semantics/publishedVersio

Revisiting phage therapy: new applications for old resources

The success of phage therapy is dependent on the development of strategies able to overcome the limitations of bacteriophages as therapeutic agents, the creation of an adequate regulatory framework, the implementation of safety protocols, and the acceptance by the general public. Many approaches have been proposed to circumvent phages intrinsic limitations but none have proved to be completely satisfactory. In this review we present the major hurdles of phage therapy and the solutions proposed to circumvent them. A thorough discussion on the advantages and drawbacks of these solutions is provided and special attention is given to genetic modification of phages as an achievable strategy to shape bacteriophages to exhibit desirable biological properties.The authors thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013 and the Project 'BioHealth - Biotechnology and Bioengineering approaches to improve health quality, Ref. NORTE-07-0124-FEDER-000027' cofunded by the Programa Operacional Regional do Norte (ON.2 - O Novo Norte), QREN, and FEDER. F.L.N. also acknowledges the FCT for grant SFRH/BD/86462/2012

Electrical resistivity and spatial variation in agriculture terraces: statistical correlation between ert and flow direction algorithms

The construction of earthen embankmentterraces in the Douro Region raises a set of problemsrelated to hydrological processes. The main objectiveof this study is the evaluation of the spatial variationof electrical resistivity in agriculture terraces at Dourovalley (Portugal). To achieve this objective, two variablesare analysed, the soil electrical resistivity and the flowdirection algorithm. In a field survey we recorded 13electrical resistivity profiles. The contributing area wascalculated with the algorithms D (Deterministic InfinityFlow) and MFD (Multiple Flow Direction) and the results arethe base of the internal runoff modelling, both supportedby the digital elevation model with a spatial resolutionof 1m2. A correlation between the spatial variation ofthe soil electrical resistivity represented by the standarddeviation of the electrical resistivity for each profile andthe average value of the contributing area coincident witheach profile was established. The electrical resistivitystandard deviation seems to be moderately well correlatedaccording to the D algorithm at about 1m of depth, and ithas a good correlation at 1,5m to 2m of depth with the MFDalgorithm. Taken together, the results show a significantpositive statistical correlation between the electricalresistivity standard deviation and the contributing areas(MFD and D) depending on the soil depth

Technological progresses in monoclonal antibody production systems

Monoclonal antibodies (mAbs) have become vitally important to modern medicine and are currently one of the major biopharmaceutical products in development. However, the high clinical dose requirements of mAbs demand a greater biomanufacturing capacity, leading to the development of new technologies for their large-scale production, with mammalian cell culture dominating the scenario. Although some companies have tried to meet these demands by creating bioreactors of increased capacity, the optimization of cell culture productivity in normal bioreactors appears as a better strategy. This review describes the main technological progresses made with this intent, presenting the advantages and limitations of each production system, as well as suggestions for improvements. New and upgraded bioreactors have emerged both for adherent and suspension cell culture, with disposable reactors attracting increased interest in the last years. Furthermore, the strategies and technologies used to control culture parameters are in constant evolution, aiming at the on-line multiparameter monitoring and considering now parameters not seen as relevant for process optimization in the past. All progresses being made have as primary goal the development of highly productive and economic mAb manufacturing processes that will allow the rapid introduction of the product in the biopharmaceutical market at more accessible prices. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 201

Guidelines to cell engineering for monoclonal antibody production

Monoclonal antibodies (mAbs) are currently used for many diagnostic and therapeutic applications. The high demand for these biopharmaceuticals has led to the development of large-scale manufacturing processes, with productivity improvements being mainly achieved by optimization of bioreactor systems. However, more recently, the early steps of production, previous to bioreactor culture, have been presented as alternative areas where productivity enhancements can be achieved. Thus, this review describes the progress made for the improvement of productivity in mammalian expression systems for the high production of mAbs. Advances in the development of mAb-producing cell lines are being made, particularly regarding expression vector design and methods used for transfection, with the intent to create a reproducible methodology. Selection of the most suitable clones is also a critical step that can be improved, by including variables other than the expression level, which is still the common practice. Furthermore, strategies of cell engineering, although still mostly based on trial-and-error experimentation and not in standard protocols, hold great interest to improve cell growth and productivity, as well as product quality in the future. Improvements of the initial steps of the production process would not only result in cells with higher expression ability, but would also speed-up the process development

A new approach for determination of Na,K-ATPase activity: application to intact pancreatic ß-cells

It has been postulated that a decrease in Na,KATPase-mediated ion gradients may be a contributing mechanism to insulin secretion. However, the precise role of the Na,K-ATPase in pancreatic β-cell membrane depolarization and insulin secretion signalling have been difficult to evaluate, mostly because data reporting changes in enzymatic activity have been obtained in cell homogenates or membrane preparations, lacking intact intracellular signalling pathways. The aim of this work was to develop a method to characterize Na,K-ATPase activity in intact pancreatic β-cells that will allow the investigation of putative Na,K-ATPase activity regulation by glucose and its possible role in insulin secretion signalling. This work demonstrates for the first time that it is possible to determine Na,K-ATPase activity in intact pancreatic βcells and that this is a suitable method for the study of the mechanisms involved in the Na,K-ATPase regulation and eventually its relevance for insulin secretion signalling