273 research outputs found

    A review of hemorheology : measuring technologies and recent advances

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    Significant progress has been made over the years on the topic of hemorheology, not only in terms of the development of more accurate and sophisticated techniques, but also in terms of understanding the phenomena associated with blood components, their interactions and impact upon blood properties. The rheological properties of blood are strongly dependent on the interactions and mechanical properties of red blood cells, and a variation of these properties can bring further insight into the human health state and can be an important parameter in clinical diagnosis. In this article, we provide both a reference for hemorheological research and a resource regarding the fundamental concepts in hemorheology. This review is aimed at those starting in the field of hemodynamics, where blood rheology plays a significant role, but also at those in search of the most up-to-date findings (both qualitative and quantitative) in hemorheological measurements and novel techniques used in this context, including technical advances under more extreme conditions such as in large amplitude oscillatory shear flow or under extensional flow, which impose large deformations comparable to those found in the microcirculatory system and in diseased vessels. Given the impressive rate of increase in the available knowledge on blood flow, this review is also intended to identify areas where current knowledge is still incomplete, and which have the potential for new, exciting and useful research. We also discuss the most important parameters that can lead to an alteration of blood rheology, and which as a consequence can have a significant impact on the normal physiological behavior of blood

    Development of highly sensitive temperature microsensors for localized measurements

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    This paper presents the design, fabrication and characterization of temperature microsensors based on Resistance Temperature Detectors (RTDs) with a meander-shaped geometry. Numerical simulations were performed for studying the sensitivity of the RTDs according to their windings numbers as well as for optimizing their layout. These RTDs were fabricated using well-established microfabrication and photolithographic techniques. The fabricated sensors feature high sensitivity (0.3542 mV/°C), linearity and reproducibility in a temperature range of 35 to 45 °C. Additionally, each sensor has a small size with a strong potential for their integration in microfluidic devices, as organ-on-a-chip, allowing the possibility for in-situ monitoring the physiochemical properties of the cellular microenvironment.This work is the result of the project NORTE-01-0145-FEDER-029394, RTChip4Theranostics, and was supported by Programa Operacional Regional do Norte–Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement through the European Regional Development Fund (FEDER) and by Fundação para a Ciência e Tecnologia (FCT), IP, project reference PTDC/EMD-EMD/29394/2017. The authors also acknowledge the partial financial support by the projects UIDB/04436/2020 and UIDP/04436/2020

    Communication strategy for a collaborative store of sustainable fashion brands

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    DOI (European Journal of Applied Business and Management): https://doi.org/10.58869/EJABM ; Special Issue 2022 - Circular EconomyObjetivo: O presente estudo visa conhecer, analisar e criar a identidade de marca de uma loja colaborativa de pequenas marcas de moda sustentável. Simultaneamente, pretende- se também criar um plano estratégico de comunicação aplicado a essa loja. Metodologia: Numa primeira fase aplicar-se uma abordagem qualitativa, inicialmente com exploração de casos de estudo. Seguidamente, recorre-se a metodologias de design para a parte prática de criação da marca, nomeadamente a metodologia do Design Thinking Evolution 6. Resultados: Os resultados mostram que ainda se verifica pouca transparência na abordagem de temas como a moda e a sustentabilidade, apesar de já existi uma oferta considerável. Implicações Práticas: O surgimento de marcas de moda com cunho sustentável, é ascendente, neste modo é importante construir uma identidade coesa e um plano de comunicação estruturado como elementos diferenciadores de marcas no mercado. Limitações da investigação: Por se tratar de uma abordagem preliminar, o presente estudo apresenta limitações nos resultados finais, carecendo assim de um aprofundamento do mesmo, pois existe muitos tópicos da comunicação que ficaram por explorar. Originalidade: Pretende-se que o conceito que está por trás deste estudo seja um bom contributo para pequenas marcas de moda, de cunho sustentável, auxiliando-as quer na criação de identidade das suas próprias marcas, como na estruturação de um plano estratégico de comunicação.Purpose: The present study aims to know, analyze, and create the brand identity of a collaborative store of small sustainable fashion brands. At the same time, it is also intended to create a strategic communication plan applied to this store. Methodology: In a first phase, apply a qualitative approach, initially with the exploration of case studies. Then, design methodologies are used for the practical part of brand creation, namely the Design Thinking Evolution 6 methodology. Findings: The results show that there is still little transparency in the approach to topics such as fashion and sustainability, although there is already a considerable offer. Practical implications: The emergence of sustainable fashion brands is ascendant, in this way it is important to build a cohesive identity and a structured communication plan as differentiating elements of brands in the market. Research limitations: As it is a preliminary approach, the present study has limitations in the final results, thus requiring a deeper understanding of it, as there are many communication topics that remain to be explored. Originality: It is intended that the concept behind this study is a good contribution to small fashion brands, of a sustainable nature, helping them both in creating their own brand identity and in structuring a strategic communication plan

    A review of conventional and emerging technologies for hydrogels sterilization

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    Funding This work was financially supported by Fundaçao ˜ para a Ciˆencia e Tecnologia (FCT), Portugal, through the project STERILAEROGEL – Green method to prepare sterilised biopolymer-based aerogel (POCI01–0145-FEDER-032625) and Strategic Projects FCT-MEC PEst-C/EQB/ UI0102/2019, UIDB/00102/2020 and Programmatic Project UIDP/ 00102/2020 of the CIEPQPF, and UI/05704/2020 of the ciTechCare. C. S. A. Bento acknowledges for PhD grant UI/BD/151008/2021 and M. C. Gaspar acknowledges FCT for the financial support under Scientific Employment Stimulus – Individual and Institutional Calls (CEECIND/ 00527/2017 and CEECINST/00060/2021).Hydrogels are extensively used in the biomedical field, as drug delivery systems, wound dressings, contact lenses or as scaffolds for tissue engineering. Due to their polymeric nature and the presence of high amounts of water in their structure, hydrogels generally present high sensitivity to terminal sterilization. The establishment of an efficient sterilization protocol that does not compromise the functional properties of the hydrogels is one of the challenges faced by researchers when developing a hydrogel for a specific application. Yet, until very recently this aspect was largely ignored in the literature. The present paper reviews the state of literature concerning hydrogels sterilization, compiling the main findings. Conventional terminal sterilization methods (heat sterilization, radiation sterilization, and gas sterilization) as well as emerging sterilization techniques (ozone, supercritical carbon dioxide) are covered. Considerations about aseptic processing are also included. Additionally, and as a framework, hydrogels’ polymeric materials, types of networks, and main biomedical applications are summarily described.info:eu-repo/semantics/publishedVersio

    Self-perception of factors that precipitate or inhibit seizures in juvenile myoclonic epilepsy

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    SummaryPurpose:To assess self-perception of factors that precipitate or inhibit seizures in patients with juvenile myoclonic epilepsy (JME).Patients and methods:Thirty-six males and 39 females with JME and mean age of 25.8±8.7 years were analysed. All patients completed a standardized questionnaire to assess for the presence or absence of precipitant or inhibitory factors for their seizures in a face-to-face interview. These data were statistically analysed through logistic and linear regression models and Phi coefficient.Results:Ninety-two percent of the patients identified at least one precipitating factor (PF). In order of frequency the following PFs were recorded: stress (83%), sleep deprivation (77%), specific thoughts/mental concentration (23%), performance of hand activities and complex finger movements (20%), flashing lights and playing games (15%), speaking out in public (11%) and alcohol intake (11%), reading (7%), calculating and writing (5%), playing musical instruments (4%), drawing (3%), and specific types of music (1%). Menstrual cycle was the third most important PF in the women (33%). Although PFs were easily recognized, 77% of the patients stated that they were unable to avoid the occurrence of the seizures.Conclusions:Structured questionnaire is useful in stimulating patients to self-report seizure precipitants. Patients with higher education and uncontrolled seizures identified them more easily. The presence of a significant number of uncommon PFs, such as mental and motor hand tasks, considered uncommon for other epileptic syndromes, suggests that the role of these factors may be under-recognized in JME

    Improving the downstream processing of interferon alfa-2b using alternative purification platforms based on ionic liquids

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    Improvements on human life expectancy and the lack of effective therapies has led to an increment of chronic diseases, being the application of biopharmaceuticals an efficient strategy to mitigate this scenario. Among the current available biopharmaceuticals, the role of interferon α-2b (IFNα-2b) should be highlighted, as it has been marketed over 30 years with a considerable impact on the global therapeutic proteins market (Castro et al, Vaccines, 2021). IFN manufacturing requires the use of the recombinant DNA technology, involving two main stages, the upstream and downstream stages. The first includes recombinant protein production in a suitable host microorganism, such as Escherichia coli (Castro et al, Sep. Purif. Technol., 2020), while the second comprises protein recovery, isolation, purification and polishing. Due to the high demands of the pharmaceutical industry for products with high purity and biological activity, the downstream stage is responsible for the majority of the production costs of biopharmaceuticals (50–90%), often including time-consuming and multi-step processes. Therefore, there is an immediate need to develop more efficient, cost-effective, and sustainable protein purification methodologies. In this work, two ionic-liquid-(IL)-based strategies were investigated for the purification of IFNα-2b recombinantly produced from E. coli fermentation broth, namely as adjuvants in aqueous biphasic systems or as chromatographic ligands immobilized in solid materials. Overall, the obtained results demonstrate that by tailoring IL’s chemical structures, improved protein purification processes are obtained and that the secondary structure of proteins is preserved.publishe

    Sustainable ionic-liquid-based strategies for the downstream processing of interferon α-2b from Echerichia coli

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    Over the last decades, society has been facing an increment of chronic diseases due to the higher human life expectancy and the lack of efficient treatments for several pathologies. In this regard, biopharmaceuticals have become one of the most effective clinical treatments for a broad range of diseases, including cancer, metabolic and neurodegenerative disorders [1]. Among biopharmaceuticals, the role of interferons, particularly interferon α-2b (IFNα-2b), should be underlined, as they have been marketed for over 30 years with a considerable impact on the global therapeutic proteins market [2]. Usually based on the recombinant DNA technology, the manufacturing process of biopharmaceuticals encompasses two main stages: the upstream and downstream stages. Typically, the upstream phase includes recombinant protein production processes in a suitable host microorganism, such as Escherichia coli [3], while the general downstream processing of biopharmaceuticals comprises four stages - recovery, isolation, purification and polishing -, which are responsible for the majority of the production costs of biopharmaceuticals (50–90%) [3]. The downstream processing is a time-consuming and multi-step process, for which the development of cost-effective purification processes is mandatory to decrease their costs and environmental impact. In this context, two ionic-liquid-(IL)-based strategies were investigated in this work for the purification of IFNα-2b recombinantly produced from E. coli fermentation broth. ILs have been used as adjuvants in aqueous two-phase systems (ATPS) and applied in supported materials as alternative ligands. The obtained results demonstrate that ILs have a tailoring ability and contribute to the development of more effective and sustainable downstream processes of biopharmaceuticals.publishe

    In vitro blood flow and cell-free layer in hyperbolic microchannels: visualizations and measurments

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    Red blood cells (RBCs) in microchannels has tendency to undergo axial migration due to the parabolic velocity profile, which results in a high shear stress around wall that forces the RBC to move towards the centre induced by the tank treading motion of the RBC membrane. As a result there is a formation of a cell free layer (CFL) with extremely low concentration of cells. Based on this phenomenon, several works have proposed microfluidic designs to separate the suspending physiological fluid from whole in vitro blood. This study aims to characterize the CFL in hyperbolic-shaped microchannels to separate RBCs from plasma. For this purpose, we have investigated the effect of hyperbolic contractions on the CFL by using not only different Hencky strains but also varying the series of contractions. The results show that the hyperbolic contractions with a Hencky strain of 3 and higher, substantially increase the CFL downstream of the contraction region in contrast with the microchannels with a Hencky strain of 2, where the effect is insignificant. Although, the highest CFL thickness occur at microchannels with a Hencky strain of 3.6 and 4.2 the experiments have also shown that cells blockage are more likely to occur at this kind of microchannels. Hence, the most appropriate hyperbolic-shaped microchannels to separate RBCs from plasma is the one with a Hencky strain of 3.The authors acknowledge the financial support provided by PTDC/SAU-ENB/116929/2010 and EXPL/EMS-SIS/2215/2013 from FCT (Fundação para a Ciência e a Tecnologia), COMPETE, QREN and European Union (FEDER). R.O. Rodrigues, D. Pinho and P. C. Sousa acknowledge the scholarships SFRH/BD/97658/2013, SFRH/BD/89077/2012 and SFRH/BPD/75258/2010, respectively, all attributed by FCT

    Street food in Maputo, Mozambique: The coexistence of minimally processed and ultra-processed foods in a country under nutrition transition

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    The aim was to characterise the extent of processing and nutritional composition of the street foods offered in Maputo, Mozambique. A cross-sectional study was conducted in October November 2014 in the urban district of KaMpfumu. Twenty public transport stops were randomly selected, around which 500 meters buffers were drawn. All streets within these buffers were can-vassed to identify all street food vending sites. Street food offer was assessed through interviews. Nutritional composition was estimated using standardised recipes (for homemade foods), food labels (for industrial products) and food composition tables (for in natura foods). The processing extent was classified using the NOVA food classification. A total of 810 vending sites were assessed. Unprocessed/minimally processed foods were available at 70.5% of vending sites (mainly fruit, water, and tea) and ultra-processed foods at 59.0% (mostly cakes, cookies, confectionery, and soft drinks). Energy content per 100 g of unprocessed or minimally processed foods was significantly lower than in all other food groups. In all food groups, contribution to total energy value was highest for carbohydrates (range: 33.151.2%), followed by fats (range: 29.336.0%) and protein (range: 6.818.6%). Public health policies targeting the improvement of this urban food environment should consider not only the nutritional composition but also the processing extent of the foods and beverages available. (c) 2021 by the authors. Licensee MDPI, Basel, Switzerland

    Gamma Irradiation Processing on 3D PCL Devices—A Preliminary Biocompatibility Assessment

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    Funding Information: Mariana Vieira Branquinho (SFRH/BD/146172/2019), Ana Catarina Sousa (SFRH/BD/146689/2019), and Bruna Lopes (2021.05265.BD) acknowledge the Fundação para a Ciência e Tecnologia (FCT)’s financial support. Rui Damásio Alvites acknowledges the Animal Science Studies Centre (CECA), Agroenvironment, Technologies and Sciences Institute (ICETA), Porto University (UP), and FCT for the funding and availability of all technical, structural, and human resources necessary for the development of this work. The work was supported through the project UIDB/00211/2020 funded by FCT/MCTES, national funds. This research was funded by Projects PEst-OE/AGR/UI0211/2011 from FCT, and COMPETE 2020, from ANI–Projetos ID&T Empresas em Copromoção, by the project “Print-on-Organs–Engineering bioinks and processes for direct printing on organs” with the reference POCI-01-0247-FEDER-033877, by the project “Bone2Move-Development of “in vivo” experimental tech-niquesand modelling methodologies for the evaluation of 4D scaffolds for bone defect in sheepmodel: an integrative research approach” with the reference POCI-01-0145-FEDER-031146. Publisher Copyright: © 2022 by the authors.Additive manufacturing or 3D printing applying polycaprolactone (PCL)-based medical devices represents an important branch of tissue engineering, where the sterilization method is a key process for further safe application in vitro and in vivo. In this study, the authors intend to access the most suitable gamma radiation conditions to sterilize PCL-based scaffolds in a preliminary biocompatibility assessment, envisioning future studies for airway obstruction conditions. Three radiation levels were considered, 25 kGy, 35 kGy and 45 kGy, and evaluated as regards their cyto- and biocompatibility. All three groups presented biocompatible properties, indicating an adequate sterility condition. As for the cytocompatibility analysis, devices sterilized with 35 kGy and 45 kGy showed better results, with the 45 kGy showing overall improved outcomes. This study allowed the selection of the most suitable sterilization condition for PCL-based scaffolds, aiming at immediate future assays, by applying 3D-customized printing techniques to specific airway obstruction lesions of the trachea.publishersversionpublishe
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