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Institute for Bioengineering and Biosciences
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Plasma-enabled growth of vertically oriented carbon nanostructures for AC line filtering capacitors
Publication . Bundaleska, N.; Felizardo, E.; Santhosh, N. M.; Upadhyay, K. K.; Bundaleski, N.; Teodoro, O. M. N. D.; Botelho do Rego, A. M.; Ferraria, A. M.; Zavašnik, J.; Cvelbar, U.; Abrashev, M.; Kissovski, J.; Mão de Ferro, A.; Gonçalves, B.; Alves, L. L.; Montemor, M. F.; Tatarova, E.; CeFITec – Centro de Física e Investigação Tecnológica; DF – Departamento de Física; North-Holland | Elsevier
Self-standing vertically oriented carbon nanostructures (VCNs) were synthesized using a large-scale microwave plasma under low-pressure conditions, employing methane as a carbon precursor. The influence of plasma operational and substrate conditions on nanostructure growth and morphology were systematically studied. Furthermore, post-synthesis N-doping of VCNs with nitrogen content of 2.4 at% N was achieved using an Ar-N2 microwave plasma. Plasma-enabled direct deposition of VCNs, both doped and un-doped, onto nickel foils has been accomplished. The assessment of the developed nanostructures as electrodes in high-frequency AC filtering capacitors, has demonstrated an overall capacitance of approximately 480 µF at 100 Hz, with a cut-off frequency of 4 kHz for a phase angle of −45°. The excellent electrochemical performance can be attributed to the appropriate structural and morphological properties peculiar for the directly deposited on nickel foil VCNs providing binder-free electrode fabrication, thus enhancing the electrode's conductivity and charge transfer kinetics. This plasma-enabled approach for electrode design on a large scale, coupled with excellent filtering performance, paves the way for many applications in high-frequency scenarios, offering an environmentally friendly alternative to conventional electrolytic capacitors.
Edible flowers of Helichrysum italicum
Publication . Primitivo, Maria João; Neves, Marta; Pires, Cristiana L.; Cruz, Pedro F.; Brito, Catarina; Rodrigues, Ana C.; de Carvalho, Carla C. C. R.; Mortimer, Megan M.; Moreno, Maria João; Brito, Rui M. M.; Taylor, Edward J.; Millson, Stefan H.; Reboredo, Fernando; Jorge Campos, Maria; Vaz, Daniela C.; Ribeiro, Vânia S.; DCT - Departamento de Ciências da Terra; GeoBioTec - Geobiociências, Geoengenharias e Geotecnologias; Elsevier Science B.V., Amsterdam.
Helichrysum italicum (H. italicum) is a halophyte shrub with bright yellow flowers with a strong curry-like aroma. The essential oils of H. italicum have been used in the production of cosmetics and pharmaceuticals, due to their antiallergic and anti-inflammatory properties. In the agri-food sector, H. italicum flowers can be used for seasoning and flavoring food, and as natural food preservatives. Here, we report on the composition, bioactive compounds, and nutritive value of H. italicum flowers. Flowers were mainly composed of carbohydrates (>80 % dry weight), followed by minerals (6.31 ± 0.95 % dw), protein (5.44 ± 0.35 % dw), and lipids (3.59 % ± 0.53 % dw). High percentages of Fe, Zn, Ca, and K were found in the flower material, along with a high content in antioxidants, polyphenols, and carotenoids, as corroborated by the nuclear magnetic resonance (NMR) data. Flowers were mainly composed of saturated fatty acids (SFAs) (54.50 ± 0.95 % of total FA), followed by polyunsaturated fatty acids (PUFAs) (37.73 ± 1.25 % of total FA) and monounsaturated fatty acids (MUFAs) (7.77 ± 0.34 %), as detected by gas chromatography mass spectrometry (GC–MS). The omega-6 PUFA linoleic acid (22.55 ± 0.76 % of total FA) was the most abundant fatty acid found. Flower extracts showed antimicrobial activity against Saccharomyces cerevisiae and Komagataella phaffii, as well as against Gram-negative (Klebsiella pneumoniae) and Gram-positive (Staphylococcus aureus) bacteria. H. italicum flower material was nontoxic to human intestinal Caco-2 model cells at concentrations up to 1.0 % w/v.
Towards Cost-Efficient Culture of Human Induced Pluripotent Stem Cells in Vertical-Wheel Bioreactors
Publication . Salvador, William Lewis Sullivan Coutinho de Oliveira e Sousa; Rodrigues, Carlos; Henriques, Célia
Human induced pluripotent stem cells (hiPSCs) have the ability to self-renew and to
differentiate into any cell type of the human body. For this reason they possess various
promising applications in disease modeling, drug discovery and regenerative medicine.
However, these applications require large quantities of hiPSCs, in the range of one to ten
billion cells. This work sought to identify and explore strategies with the potential to establish
an economically viable bioprocess capable of producing these large quantities of hiPSCs.
Vertical-wheel bioreactors (VWBRs) and B8 culture medium are among these strategies. An
economic model of a bioprocess envisaging the large-scale expansion of hiPSCs was
developed. The model allowed for the confirmation and quantification of the economic impact
of the considered strategies. It was observed that the supplementation of the culture medium
with dextran sulfate significantly reduced the total bioprocess cost by 38%. The same occurs
when low seeding densities are employed, with a reduction of 29%. The use of B8 instead of a
commercial medium achieves a reduction of 58% in the best case scenario. At the same time,
this work sought to reproduce the B8 formula so that it could be tested jointly with VWBRs.
The B8 produced was ineffective at maintaining the viability of hiPSCs, although it did not
negatively affect their expression of pluripotency markers. The implementation of the
strategies analyzed in this work could contribute towards the establishment of the desired
bioprocess, promoting the realization of the predicted applications of hiPSCs.
Plasma-enabled multifunctional platform for gram-scale production of graphene and derivatives
Publication . Dias , Ana; Felizardo, Edgar; Bundaleska, Neli; Abrashev, Miroslav; Kissovski, Jivko; Ferraria, Ana M.; Rego, Ana M.; Strunskus, Thomas; Carvalho, Patrícia A.; Almeida, Amélia; Zavašnik, Janez; Kovacevic, Eva; Berndt, Johannes; Bundaleski, Nenad; Ammar, Mohammed Ramzi; Teodoro, Orlando M. N. D.; Cvelbar, Uroš; Alves, Luís L.; Gonçalves, Bruno; Tatarova, Elena; CeFITec – Centro de Física e Investigação Tecnológica; DF – Departamento de Física; Elsevier
Taking advantage of the high-energy-density microwave plasma environment as a unique 3D space for the self-assembly of free-standing nanostructures, a novel multifunctional platform for the continuous production of graphene and derivatives at the gram scale was developed. The platform is supported by a prototype plasma machine capable of performing a wide variety of industrially applicable processes within a single assembly environment. Free-standing graphene and nitrogen doped graphene, i.e., N-graphene nanosheets, and hybrid nanocomposites are assembled in a one-step process in seconds under atmospheric pressure conditions without the need of post-treatment. A single custom-designed machine enables the synthesis of an extensive array of hybrid nanomaterials featuring metal nanoparticles anchored in graphene. The method enables the conversion of a wide range of low-cost feedstock (e.g., ethanol, acetonitrile, etc.) into graphene and derivatives at a rate up to 30 mg/min. The resulting N-graphene sheets exhibit high quality, as evidenced by the highest reported presence of single atomic layers (45%), high ratio of 2D/G peak intensities in Raman spectra and N/O atomic ratio greater than one. The use of the obtained N-graphene in low secondary electron emission applications and in inkjet printing are explored. The presented plasma machine embodies significant potential to increase the effectiveness of plasma-driven process regarding productivity, costs and turnaround time.
Long-lived NIR emission in sulfur-doped zeolites due to the presence of [S3]2- clusters
Publication . Viola, Catarina; Laia, César A. T.; Outis, Mani; Ferreira, Luís F. V.; Alves, Luís C.; Teixeira, Miguel; Folgosa, Filipe; Lima, João C.; Ruivo, Andreia; Avó, João; DQ - Departamento de Química; LAQV@REQUIMTE; VICARTE - Vidro e Cerâmica para as Artes; Instituto de Tecnologia Química e Biológica António Xavier (ITQB); Elsevier
The exploration of novel long-lived near-infrared (NIR) luminescent materials has attracted significant attention due to their applications in optical communications, anticounterfeiting, and bioimaging. However, these materials usually present low photoluminescence quantum yields and low photo- and chemical stability. Novel emitters that overcome these limitations are in demand. In this study, NIR emission was achieved using widely available, sustainable, and non-toxic materials through the synthesis of sulfur-doped zeolites, with different S/Cl ratios. With a combination of computational calculations (TD-DFT) and spectroscopic data, this emission was assigned to the radiative decay of excited triplet states of [S3]2- clusters, which resulted in a remarkably high Stokes shift (1.97 eV, 440 nm) and an average decay time of 0.54 ms. These new materials present high stability, external quantum efficiency of up to 17%, and a long-lived NIR emission, placing these compounds in a unique position to be used in applications demanding NIR emitters.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
6817 - DCRRNI ID
Número da atribuição
UIDP/04565/2020