Export 4224 results:
Sort by: Author Title Type [ Year  (Desc)]
2017
Boavida, NFFG.  2017.  The role of indicators in decisions of technology innovation. , Karlsruhe: KIT Scientific Publishing AbstractWebsite

There are thousands of indicators produced to understand and govern our societies. Studies about the way indicators are used in technological innovation are significantly rare, despite the centrality of these decisions to promote growth in our technology-intensive civilization. This book presents what is known and what was discovered in a doctoral research, which analysed innovative business leaders, policymakers and public researchers responsible for technological innovations.

Maiti, BK, Almeida RM, Moura I, Moura JJG.  2017.  Rubredoxins derivatives: Simple sulphur-rich coordination metal sites and its relevance for Biology and Chemistry. Coord Chem Rev. 352:379-397.
Santos, Â, Vilarigues M.  2017.  Sanguine Paint: Historical Recipes for Production and Application. Proceedings of Society of Glass Technology Annual Conference (SGT 2017) - Corpus Vitrearum / ICOMOS. :190-201., Cambridge
Batista, A, Pereira A.  2017.  Software Development for the Detection and Characterization of Rail Corrugation. Workshop on Railway track dynamics. : Faculty of Sciences and Technology/UNL
Dantas, JM, Silva MA, Pantoja-Uceda D, Turner DL, Bruix M, Salgueiro CA.  2017.  Solution structure and dynamics of the outer membrane cytochrome OmcF from Geobacter sulfurreducens. Biochimica et Biophysica Acta (BBA) - Bioenergetics. 1858(9):733-741. AbstractWebsite

ABSTRACTGene knock-out studies on Geobacter sulfurreducens cells showed that the outer membrane-associated monoheme cytochrome OmcF is involved in respiratory pathways leading to the extracellular reduction of Fe(III) and U(VI). In addition, microarray analysis of an OmcF-deficient mutant revealed that many of the genes with decreased transcript level were those whose expression is up-regulated in cells grown with a graphite electrode as electron acceptor, suggesting that OmcF also regulates the electron transfer to electrode surfaces and the concomitant electricity production by G. sulfurreducens in microbial fuel cells. 15N,13C–labeled OmcF was produced and NMR spectroscopy was used to determine the solution structure of the protein in the fully reduced state and the pH-dependent conformational changes. In addition, 15N relaxation NMR experiments were used to characterize the overall and internal backbone dynamics of OmcF. The structure obtained is well defined, with an average pairwise root mean square deviation of 0.37 Å for the backbone atoms and 0.98 Å for all heavy atoms. For the first time a solution structure and the protein motions were determined for an outer membrane cytochrome from G. sulfurreducens, which constitutes an important step to understand the extracellular electron transfer mechanism in Geobacter cells.

Johnston, EM, Carreira C, Dell'Acqua S, Dey SG, Pauleta SR, Moura I, Solomon EI.  2017.  Spectroscopic definition of the CuZ° intermediate in turnover of nitrous oxide reductase and molecular insight into the catalytic mechanism. J Am Chem Soc. 139:4462-4476.
Cordeiro, T, Castiñeira C, Mendes D, Danède F, Sotomayor J, Fonseca IM, da Silva GM, Paiva A, Barreiros SF, Cardoso MM, Viciosa MT, Correia NT, Dionísio M.  2017.  Stabilizing Unstable Amorphous naproxen through Inclusion in Mesoporous Silica Hosts. Molecular Pharmaceutics. 14:3164−3177.Website
Vicente, AT, et al.  2017.  A statistics modeling approach for the optimization of thin film photovoltaic devices. Solar Energy. 144:232-243.
Gonzalez, PJ, Rivas MG, Moura JJG.  2017.  Structure, function and mechanisms of respiratory nitrate reductases. Metalloenzymes in Denitrification: Applications and Environmental Impacts, RSC Metallobiology Series No. 9 (ISBN: 978-1-78262-376-2).. (Moura, I., Moura, J. J. G., Pauleta, S. R., Maia, L. B., Eds.).:39-58.: Royal Society of Chemistry
Machado, A, Wolf S, Coutinho ML, Alves LC, Katona-Serneels I, Serneels V, S.Trümpler, Vilarigues M.  2017.  Swiss stained-glass panels - an analytical study. Microscopy and Microanalysis. 23 (4):878-890.
Sousa, DM, Lima JC, Ferreira I.  2017.  Synthesis of Cadmium Selenide Quantum Dots, Using 2, 2‐Bipyridine as a Capping and Phase Transfer Agent. ChemistrySelect. 2(3):1271-1274. AbstractWebsite

Cadmium selenide quantum dots (CdSe QDs), were synthesized by one‐pot or water‐to‐organic phase transfer and capped with molten 2,2′‐bipyridine (bipy). The obtained CdSe QDs by the two‐step procedure, reveal average sizes of 2 nm while the one‐pot are mixed with secondary salt products and bipy and are undetectable by TEM. However the absorption peak of both CdSe QDs was at 425 nm and the emission band is centered at 535 nm, with a band width at half height of 77 nm, when excited with 425 nm light. The two‐step CdSe QDs synthesis has the great advantage of capping the CdSe QDs with bipy, forming a solid phase, which is easily stored and dispersed in most of the organic solvents. On the other hand, the one‐pot procedure requires an extra step to remove the secondary products.

Dardouri, M, Borges JP, Omrani A.  2017.  Tailoring the morphology of hydroxyapatite particles using a simple solvothermal route. Ceramics International. 43(4):3784-3791. AbstractWebsite

Nanometric and sub-micrometric monodispersed hydroxyapatite (HAp) particles with different morphologies (spheres and rods) were synthesized via a simple solvothermal method using Ca(NO3)2·4H2O and P2O5 as starting materials without any requirement to use organic templates. The growth, evolution and purity of the nanoparticles were investigated by controlling the synthesis conditions, including the alkalinity and the temperature of the solvothermal treatment. The increasing of the alkaline ratio results in a great change of the elaborated particles’ morphology that evolved from anisotropic forms (nanorods, sub-micrometric rod) at pH 9, short rod particles at pH 9.5 to spherical ones at higher pH (pH≥10).
Powder X-Ray diffractometry (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and Nitrogen adsorption and desorption studies (BET) were used to characterize the structure and composition of the as-prepared samples.
The thermal analysis of the synthesized particles conducted by differential scanning calorimetry (DSC) shows a good stability for all morphologies with a degradation temperature reaching 1300 °C.

Lakhdar, A, Borges JP, Amara A, Omrani A.  2017.  Template-free synthesis of sub-micrometric cobalt fibers with controlled shape and structure. Characterization and magnetic properties. Journal of Magnetism and Magnetic Materials. 425:6-11. AbstractWebsite

Sub-micrometric Co fibers were prepared via a modified polyol process at 90 °C under an external magnetic field of about 550 Oe, using ethelyne glycol as solvent and hydrazine as reducing agent. The structure, the size and the morphology of the as-elaborated products were highly controlled through properly monitoring the synthesis parameters (amount of NaOH added, the amount of the reducing agent, precursor’ concentration and precursors mixing protocol). The XRD characterization confirmed the formation of pure cobalt powders with either hexagonal compact (hcp) or face-centered-cubic (fcc) structure depending on the concentration of the metal precursor and sodium hydroxide. The scanning electron microscopy observations of the powders shows sub-micrometric fibers with about 0.4–0.6 µm in diameter and a length that could reach 15 µm. Fibers prepared at high reducing ratio were constituted of flower-like spheres that coalesce in the direction of the applied magnetic field. For their high contact surface, these fibers offer new opportunities for catalysis applications. The hysteresis loop measurements show an enhancement of the Hc of the as-obtained fibers compared to their bulk counterparts and permit to confirm the relationship between the structure and the magnetic properties of the materials.

Marcelino, P, Marinho SH, Campos MC, Neves AR, Real C, Fontes FS, Carvalho A, Feio G, Martins BMF, Corvo LM.  2017.  Therapeutic activity of superoxide dismutase-containing enzymosomes on rat liver ischaemia-reperfusion injury followed by magnetic resonance microscopy. European Journal of Pharmaceutical Sciences. 109:464-471. AbstractWebsite

Liver ischaemia-reperfusion injury (IRI) may occur during hepatic surgery and is unavoidable in liver transplantation. Superoxide dismutase enzymosomes (SOD-enzymosomes), liposomes where SOD is at the liposomal surface expressing enzymatic activity in intact form without the need of liposomal disruption, were developed with the aim of having a better insight into its antioxidant therapeutic outcome in IRI. We also aimed at validating magnetic resonance microscopy (MRM) at 7 T as a tool to follow IRI. SOD-enzymosomes were characterized and tested in a rat ischaemia-reperfusion model and the therapeutic outcome was compared with conventional long circulating SOD liposomes and free SOD using biochemical liver injury biomarkers, histology and MRM. MRM results correlated with those obtained using classical biochemical biomarkers of liver injury and liver histology. Moreover, MRM images suggested that the therapeutic efficacy of both SOD liposomal formulations used was related to prevention of peripheral biliary ductular damage and disrupted vascular architecture. Therefore, MRM at 7 T is a useful technique to follow IRI. SOD-enzymosomes were more effective than conventional liposomes in reducing liver ischaemia-reperfusion injury and this may be due to a short therapeutic window.

Palma, P, Gouveia JP, Seixas J, Simões S.  2017.  Thermal Comfort in the Portuguese Households: Mapping Energy Needs at Civil Parish Level. ME3 Conference - Meeting on Energy and Environmental Economics. , Aveiro, Portugal. 21-22 September, http://www.ua.pt/degeit/me3/
Faria, J, Echeverria C, Borges JP, Godinho MH, Soares PIP.  2017.  Towards the development of multifunctional hybrid fibrillary gels: production and optimization by colloidal electrospinning. RSC Advances. 7(77):48972-48979. AbstractWebsite

The incorporation of thermosensitive microgels that can act as active sites into polymeric fibers through colloidal electrospinning originates multifunctional, highly porous, and biocompatible membranes suitable for biomedical applications. The use of polyvinylpyrrolidone (PVP), a biocompatible, water-soluble polymer as a fiber template, not only allows the use of a simple set-up to produce composite membranes, but also avoids the use of organic solvents to prepare such systems. Further crosslinking with ultraviolet (UV) radiation avoids membrane dissolution in physiological conditions. Highly porous, UV crosslinked composite membranes with monodisperse mean fiber diameters around 530 nm were successfully produced. These composite membranes showed a Young Modulus of 22 MPa, and an ultimate tensile strength of 3 MPa, accessed in the mechanical tests. Furthermore, the same composite membranes were able to swell about 30 times their weight after 1 hour in aqueous medium. In this work composite multifunctional membranes were designed and extensively studied. PVP, a biocompatible water-soluble polymer, was used as a fiber template to incorporate thermoresponsive poly-(N-isopropylacrylamide) (PNIPAAm)-based microgels into the composite membrane using colloidal electrospinning. The design of multifunctional membranes can be further tailored to several biomedical applications such as temperature-controlled drug delivery systems.

Sridhara, SC, Carvalho S, Grosso AR, Marcela L, Carmo-fonseca M, de Almeida SF.  2017.  Transcription Dynamics Prevent RNA-Mediated Genomic Instability through SRPK2-Dependent DDX23 Phohsphorylation. Cell Reports. :334–343. AbstractWebsite

Genomic instability is frequently caused by nucleic acid structures termed R-loops that are formed during transcription. Despite their harmful potential, mechanisms that sense, signal, and suppress these structures remain elusive. Here, we report that oscillations in transcription dynamics are a major sensor of R-loops. We show that pausing of RNA polymerase II (RNA Pol II) initiates a signaling cascade whereby the serine/arginine protein kinase 2 (SRPK2) phosphorylates the DDX23 helicase, culminating in the suppression of R-loops. We show that in the absence of either SRPK2 or DDX23, accumulation of R-loops leads to massive genomic instability revealed by high levels of DNA double-strand breaks (DSBs). Importantly, we found DDX23 mutations in several cancers and detected homozygous deletions of the entire DDX23 locus in 10 (17%) adenoid cystic carcinoma (ACC) samples. Our results unravel molecular details of a link between transcription dynamics and RNA-mediated genomic instability that may play important roles in cancer development.

Moniz, AB.  2017.  Transformações no mercado de trabalho e robótica. Cadernos de Economia. 30:30-34.
Prezas, P, Melo B, Costa L, Valente M, Lança MC, Ventura J, Pinto L, Prezas M.  2017.  TSDC and impedance spectroscopy measurements on hydroxyapatite, β-tricalcium phosphate and hydroxyapatite/β-tricalcium phosphate biphasic bioceramics. Applied Surface Science. 424(1):28-38. AbstractWebsite

Bone grafting and surgical interventions related with orthopaedic disorders consist in a big business, generating large revenues worldwide every year. There is a need to replace the biomaterials that currently still dominate this market, i.e., autografts and allografts, due to their disadvantages, such as limited availability, need for additional surgeries and diseases transmission possibilities. The most promising replacement materials are biomaterials with bioactive properties, such as the calcium phosphate-based bioceramics group. The bioactivity of these materials, i.e., the rate at which they promote the growth and directly bond with the new host biological bone, can be enhanced through their electrical polarization.
In the present work, the electrical polarization features of pure hydroxyapatite (Hap), pure β-tricalcium phosphate (β-TCP) and biphasic hydroxyapatite/β-tricalcium phosphate composites (HTCP) were analyzed by measuring thermally stimulated depolarization currents (TSDC). The samples were thermoelectrically polarized at 500 °C under a DC electric field with a magnitude of 5 kV/cm. The biphasic samples were also polarized under electric fields with different magnitudes: 2, 3, 4 and 5 kV/cm. Additionally, the depolarization processes detected in the TSDC measurements were correlated with dielectric relaxation processes observed in impedance spectroscopy (IS) measurements.
The results indicate that the β-TCP crystalline phase has a considerable higher ability to store electrical charge compared with the Hap phase. This indicates that it has a suitable composition and structure for ionic conduction and establishment of a large electric charge density, providing great potential for orthopaedic applications.

Hussain, A, Semeano ATS, Palma SICJ, Pina AS, Almeida J, Medrado BF, Pádua ACCS, Carvalho AL, Dionísio M, Li RWC, Gamboa H, Ulijn RV, Gruber J, Roque ACA.  2017.  Tunable Gas Sensing Gels by Cooperative Assembly. Advanced Functional Materials. 1700803:1–9. AbstractPDFWebsite

The cooperative assembly of biopolymers and small molecules can yield functional materials with precisely tunable properties. Here, the fabrication, characterization, and use of multicomponent hybrid gels as selective gas sensors are reported. The gels are composed of liquid crystal droplets self-assembled in the presence of ionic liquids, which further coassemble with biopolymers to form stable matrices. Each individual component can be varied and acts cooperatively to tune gels' structure and function. The unique molecular environment in hybrid gels is explored for supramolecular recognition of volatile compounds. Gels with distinct compositions are used as optical and electrical gas sensors, yielding a combinatorial response conceptually mimicking olfactory biological systems, and tested to distinguish volatile organic compounds and to quantify ethanol in automotive fuel. The gel response is rapid, reversible, and reproducible. These robust, versatile, modular, pliant electro-optical soft materials possess new possibilities in sensing triggered by chemical and physical stimuli.

Hussain, A, Semeano ATS, Palma SICJ, Pina AS, Almeida J, Medrado BF, Pádua ACCS, Carvalho AL, Dionísio M, Li RWC, Gamboa H, Ulijn RV, Gruber J, Roque ACA.  2017.  Tunable Gas Sensing Gels by Cooperative Assembly. Advanced Functional Materials. 27(27):1700803.Website
Echeverria, C, Almeida PL, Gutierrez OAF, Rey AD, Godinho MH.  2017.  Two negative minima of the first normal stress difference in a cellulose-based cholesteric liquid crystal: Helix uncoiling. Journal of Polymer Science Part B: Polymer Physics. 55(10):821-830. AbstractWebsite

The shear rate dependence of material functions such as shear viscosity (η) and the first normal stress difference (N1) were given and interpreted earlier by Kiss and Porter. Their widely accepted work revealed the possibility of having a negative minimum of N1 for polymeric liquid crystals. In this work, we disclose for the first time the evidence of two negative N1 minima on a sheared cellulosic lyotropic system. The lower shear rate minimum is ascribed to the uncoiling of the cholesteric helix, as theoretically predicted earlier. Our findings contribute also to the understanding of the other minimum already reported in the literature and attributed to the nematic director tumbling mode. Moreover, the elastic change that the LC-HPC sample undergoes during the helix unwinding of the cholesteric structure is also by means of oscillatory measurements. This study is a contribution for the understanding of the structure-properties relationship linked with the complex rheological behavior of chiral nematic cellulose-based systems and may help to improve their further processing.

Sousa, JR, Silveira CM, Fontes P, Roma-Rodrigues C, Fernandes AR, Van Driessche G, Devreese B, Moura I, Moura JJG, Almeida MG.  2017.  Understanding the response of Desulfovibrio desulfuricans ATCC 27774 to different electron acceptors - biosynthetic costs modulate substrate selection. Biochim Biophys Acta. 1865:1455-1469.