Management of Operational Parameters and Novel Spinneret Configurations for the Electrohydrodynamic Processing of Functional Polymers

[EN] Functional materials have become key drivers in the development of multiple high-end technologies. Electrohydrodynamic processing (EHDP) is a straightforward method to generate polymer micro- and nanostructures that can be applied to the food, pharmaceutical, environmental, and biomedical areas, among others, since these can yield materials with higher performance. Some of the EHDP's advantages over other polymer processing technologies rely on its high versatility, by which the final assembly can be modified in different ways to combine materials with multiple properties and also in different morphological structures, and the use of room processing conditions, meaning that thermolabile ingredients can be incorporated with minimal activity loss. This review provides the historical background, process basics, and the state-of-the-art of the most recent advances achieved in the EHDP technology dealing with the control of its operational parameters to optimize processability and achieve end-product quality and homogeneity. It also focuses on the newly developed modes of operation and spinneret configurations that can lead to the formation of a wide range of micro- and nanostructures with different functionalities and solve some of its current technical limitations. Finally, it also further highlights the potential applications of the resultant hierarchical functional polymer-based materials obtained by these novel EHDP methods.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and by the I&D&I AgriFood XXI project, operation number NORTE-01-0145-FEDER-000041, co-financed by the European Regional Development Fund (FEDER) under the scope of NORTE 2020 (ProgramaOperacional Regional do Norte 2014/2020). Pedro Silva is the recipient of a fellowship (SFRD/BD/130247/2017) supported by FCT. S. TorresGiner acknowledges Spanish Ministry of Science and Innovation (MICI) for the funding received during his Ramon y Cajal contract (RYC2019027784-I).Silva, PM.; Torres-Giner, S.; Vicente, AA.; Cerqueira, MA. (2022). Management of Operational Parameters and Novel Spinneret Configurations for the Electrohydrodynamic Processing of Functional Polymers. Macromolecular Materials and Engineering. 307(5):1-21. https://doi.org/10.1002/mame.202100858121307

Alginate particles for encapsulation of phenolic extract from Spirulina sp. LEB-18: physicochemical characterization and assessment of in vitro gastrointestinal behavior

Encapsulation can be used as a strategy to protect and control the release of bioactive extracts. In this work, an extract from Spirulina sp. LEB-18, rich in phenolic compounds, was encapsulated in biopolymeric particles (i.e., composed of alginate) and characterized concerning their thermal behavior using differential scanning calorimetry (DSC), size, morphology, swelling index (S), and encapsulation efficiency (EE%); the release profile of the phenolic compounds at different pHs and the particle behavior under in vitro gastrointestinal digestion were also evaluated. It was shown that it is possible to encapsulate the phenolic extract from Spirulina sp. LEB-18 in alginate particles with high encapsulation efficiency (88.97%). It was also observed that the particles are amorphous and that the encapsulated phenolic compounds were released at a pH 7.2 but not at pH 1.5, which means that the alginate particles are able to protect the phenolic compounds from the harsh stomach conditions but lose their integrity under intestinal pH conditions. Regarding bioaccessibility, it was observed that the encapsulated phenolic compounds showed higher bioaccessibility compared to phenolic compounds in free form. This work increases the knowledge about the behavior of alginate particles encapsulating phenolic compounds during in vitro gastrointestinal digestion. It also provides essential information for designing biopolymeric particle formulations encapsulating phenolic compounds for application in pharmaceutical and food products.The study was financially supported by the following programs and institutions: Science Without Borders—CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico), CSF (Ciência sem fronteiras), CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior), Brazil, the University of Minho, Braga, Portugal, and Foundation for Science and Technology (FCT, POPH-QREN and FSE Portugal). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit, and by LABBELS–Associate Laboratory in Biotechnology, Bioengineering and Microelectromechanical Systems, LA/P/0029/2020.info:eu-repo/semantics/publishedVersio

The structure and photoluminescence of erbium-doped nanocrystalline silicon thin films produced by reactive magnetron sputtering

We have produced and studied undoped and erbium-doped nanocrystalline silicon thin films in order to evaluate the erbium influence on the film microstructure and how this correlates with the photoluminescence properties. Films were grown by reactive RF sputtering. For the doped films metallic erbium was added to the c-Si target. The structural parameters and the chemical composition of the different samples were investigated by X-ray in the grazing incidence geometry, Raman spectroscopy, ellipsometry and Rutherford Back Scattering. The effect of the nc-Si/SiOx matrix ,i.e., nc-Si volume fraction and the presence of SiO and/or SiO2 phases, on the erbium photoluminescence efficiency is discussed.(undefined

New insights about the monomer and homodimer structures of the human AOX1

UID/MULTI/04378/2019. IF/01310/2013 . PhD Grant SFRH/BD/119206/2016.Human aldehyde oxidase (hAOX1) is a molybdenum dependent enzyme that plays an important role in the metabolism of various compounds either endogenous or xenobiotics. Due to its promiscuity, hAOX1 plays a major role in the pharmacokinetics of many drugs and therefore has gathered a lot of attention from the scientific community and, particularly, from the pharmaceutical industry. In this work, homology modelling, molecular docking and molecular dynamics simulations were used to study the structure of the monomer and dimer of human AOX. The results with the monomer of hAOX1 allowed to shed some light on the role played by thioridazine and two malonate ions that are co-crystalized in the recent X-ray structure of hAOX1. The results show that these molecules endorse several conformational rearrangements in the binding pocket of the enzyme and these changes have an impact in the active site topology as well as in the stability of the substrate (phthalazine). The results show that the presence of both molecules open two gates located at the entrance of the binding pocket, from which results the flooding of the active site. They also endorse several modifications in the shape of the binding pocket (namely the position of Lys893) that, together with the presence of the solvent molecules, favour the release of the substrate to the solvent. Further insights were also obtained with the assembled homodimer of hAOX1. The allosteric inhibitor (THI) binds closely to the region where the dimerization of both monomers occur. These findings suggest that THI can interfere with protein dimerization.publishe

Hybrid gels: influence of water and oil phase on textural and rheological properties

The 19th Gums & Stabilisers for the Food Industry Conference: Hydrocolloid MultifunctionalityHybrid gels are biphasic systems formed by conjugating hydrogels and oleogels. The mixture of water-based and oil-based gels provides distinct and unique characteristics to hybrid gels, and based on the structurant molecules and mixture ratio used during their production, different textural and rheological properties can be obtained. Hybrid gels remain a very recent topic concerning pharmaceutical and food applications and despite recent studies on the use of hybrid gels for controlled delivery of compounds (pharmaceutical applications) these structures are still under-studied in regard to their food application possibilities [1, 2]. To improve knowledge and expanding ways to use these systems, it is important to understand how these gels behave regarding textural and rheological properties. Also, the knowledge on their micro and nanostructure allows tailoring their properties and thus maximizing their applicability in foodstuffs. We report on how the combination of a beeswaxbased oleogel and a sodium alginate-based hydrogel influences the gel structural properties at macroscopic (rheological and textural), microscopic (optical microscopy) and molecular (Xray diffraction) levels. Different ratios of both hydrogel and oleogel were used in order to evaluate the hybrid gels’ behaviour in terms of morphological, textural, rheological and polymorphic properties. Differences regarding oleogel particles distribution in the hydrogel matrix were noticed with the increase of oleogel fraction. A more disarranged distribution of oleogel particles was observable for the 50:50 ratios of hydrogel and oleogel. X-ray diffraction data unveiled that once polycrystallinity is reached (in hybrid gels) these patterns remain persistent for all tested ratios. Oleogel showed d-spacings in the range of 3.74 to 8.04 Å. Hybrid gel samples (and hydrogel control) are semi-crystalline, displaying spacings ranging in intervals of d (001) 6.99 – 7.18 Å; d (002) 3.09 – 3.23 Å and d (003) 2.45 – 2.46 Å, respectively. The samples with increasing oleogel ratio revealed a firmness decrease and a consequent reduction of spreadability values. Consequently, is observed less adhesivity for these samples, due to a more pronounced disaggregated structure. For all hybrid gels a gellike behaviour (G´ > G´´) was observed. Results showed that it is possible to modify the hybrid gels’ rheological and textural behaviour by a controlled mixture ratio of oleogels and hydrogels. This opens the possibilities of food applications for this kind of systems.info:eu-repo/semantics/publishedVersio

findings from a Portuguese study

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Measurement of mean wear coefficient during gear tests under various operating conditions

Seven weartestswereconductedonanFZGgeartestingmachineinordertoascertaintheinfluence of basestock(PAOandmineral),specific film thicknessandcontactloadonthewearofspurgears,parti- cularlyonthewearcoefficient κ that isusedinArchard'slaw.Theresultsshowedthatloadmayhave some influence onthewearcoefficient. Theyalsoshowedthattheinfluence ofspecific film thicknesson wear isverynon-linear.Theinfluence ofbasestock,evenwithoilsofsimilarviscosity,isverysignificant, as muchasanyotherparameterinisolation.info:eu-repo/semantics/publishedVersio

Effect of alginate molecular weight and M/G ratio in beads properties foreseeing the protection of probiotics

"Available online 1 December 2017"Probiotics are live microorganisms that when administered in adequate amounts confer a health benefit to the host. However, to accomplish this positive influence on Human health, probiotics should survive to the passage through the upper digestive tract in large numbers to unsure a desired beneficial effect in the host. Several encapsulation methods have been used to protect probiotics. Alginate is the most used biopolymer in the production of these systems, although its performance is totally dependent of its structure and chemical characteristics. In this work, alginates with different molecular weights and different mannuronic and guluronic acid residues ratio (M/G ratio) were used in the encapsulation of Lactococcus lactis spp. cremoris (LLC) aiming the protection of this probiotic bacteria against the harsh conditions of digestion. Alginate-based beads were produced using an external gelation process (extrusion technique) where variables regarding the processing conditions and alginate chemical characteristics were studied to assess their relevance in this process aiming the most efficient encapsulation system. The most important variables influencing the size of alginate beads were the alginate concentration, alginate type (M/G ratio and molecular weight) and the nozzle diameter. Beads with sizes ranged between 1.9 and 3.0 mm were produced using different alginates. Fourier transform infrared (FTIR) spectroscopy showed relevant differences between beads produced proving the impact of different M/G ratios in the beads chemical structure. In general, low molecular weight and low M/G ratio alginate (Protanal LFR5/60) proved to produce the most well organized (according to SEM analyses), less permeable (pore diameter of 2.52 nm) and stronger alginate beads, moreover molecular weight and M/G ratio proved to be an important variable on the protection of probiotics against the harsh conditions of digestion. Produced beads proved to be efficient in the protection of probiotics (i.e. high viability), with the best performance presented by the medium and low molecular weight alginates.The author Philippe E. Ramos would like to thank the Post-doc fellowship to the national agency Fundação para a Ciência e a Tecnologia (UID/BIO/04469) and to the European Regional Development Fund (FEDER) through COMPETE 2020 e Programa Operacional Competitividade e Internacionalização (POCI-01-0145-FEDER-006684). The authors thank the FCT Strategic Project PEstOE/EQB/LA0023/2013 and the project “BioInddBiotechnology and Bioengineering for Improved Industrial and Agro-Food Processes”, ref. NORTE-07-0124-FEDER-000028 cofunded by the Programa Operacional Regional do Norte (ON.2eO Novo Norte), QREN, FEDER.info:eu-repo/semantics/publishedVersio

A new continuous distribution on the unit interval applied to modelling the points ratio of football teams

We introduce a new flexible distribution to deal with variables on the unit interval based on a transformation of the sinh–arcsinh distribution, which accommodates different degrees of skewness and kurtosis and becomes an interesting alternative to model this type of data. We also include this new distribution into the generalised additive models for location, scale and shape (GAMLSS) framework in order to develop and fit its regression model. For different parameter settings, some simulations are performed to investigate the behaviour of the estimators. The potentiality of the new regression model is illustrated by means of a real dataset related to the points rate of football teams at the end of a championship from the four most important leagues in the world: Barclays Premier League (England), Bundesliga (Germany), Serie A (Italy) and BBVA league (Spain) during three seasons (2011–2012, 2012–2013 and 2013–2014)