3,277 research outputs found
Considerations about the choice of a differintegrator
Proceedings of the 2nd International Conference on Computational Cybernetics, Vienna University of Technology, August 30 - September 1, 2004Despite the great advances in the theory and
applications of fractional calculus, some topics remain unclear making difficult its use in a systematic way. This paper studies the fractional difierintegration definition
problem from a systems point of view. Both local (GrunwaldLetnikov) and global (convolutional) definitions are considered. It is shown that the Cauchy formulation must be adopted since it is coherent with usual practice in signal processing and control applications .
Antimicrobial and antibiofilm activity of unionid mussels from the north of Portugal
The populations of freshwater mussels belonging to the family Unionidae have been facing drastic changes in
terms of diversity and numbers caused by constant aggressions on their natural habitat. Nevertheless, bivalves are capable of
developing strategies of defense to overcome potential aggressors. The present work aimed to assess the potential antibacterial
capacity of different species of unionid mussels from the north of Portugal. For this purpose, circulating cells (hemocytes), fluids,
and mucus were obtained by nonlethal methods from the species Anodonta anatina (Linnaeus), Anodonta cygnea (Linnaeus),
Potomida littoralis (Cuvier), and Unio delphinus (Spengler), and tested against bacterial reference strains and multidrug-resistant
isolates. The cellular fraction of A. anatina, A. cygnea, and P. littoralis showed antibacterial activity, detected by the agar disc
diffusion method, against Bacillus subtilis ATCC 6683, Pseudomonas aeruginosa ATCC 27853 and Acinetobacter baumannii
ATCC 19606. Circulating cells from P. littoralis and A. anatina also inhibited Listeria monocytogenes ATCC 19111 and A. cygnea
has also inhibited a multidrug-resistant isolate of Pseudomonas putida. The plasma of all mentioned freshwater mussels, used
directly or diluted, showed great ability to hamper or inhibit the biofilm formation of Staphylococcus aureus ATCC 25923, P.
aeruginosa ATCC 27853, and Escherichia coli ATCC 25922. Anodonta cygnea hampered the biofilm formation by Enterococcus
faecalis ATCC 29212 as well. Overall, these results showed that not only cells play a relevant role in the immune system of these
species but also the plasma, which likely contains antibiofilm substances. Anodonta cygnea stood out by presenting the best
antibacterial inhibition potential.This work was supported by the Portuguese Foundation for Science and Technology (FCT) with a research grant to M. H. (SFRH/BD/76265/2011). This article was also supported by the project INNOVMAR-Innovation and Sustainability in the Management and Exploitation of Marine Resources (NORTE-01-0145-FEDER-000035, within Research Line NOVELMAR), by North Portugal Regional Operational Programme(
NORTE2020), under the PORTUGAL2020 Partnership Agreement, and through the European Regional Development
Fund (ERDF).info:eu-repo/semantics/publishedVersio
Substratos para veiculação de Trichoderma koningii visando o controle da podridão radicular seca do feijoeiro.
O controle biológico de Fusarium so/ani f. sp. phaseoli envolve a multiplicação de antagonistas em substratos de fácil aquisição e de baixo custo. Estudos preliminares indicaram Trichoderma koningii como um antagonista promissor; e a palhada de milho e um lixo orgânico beneficiado como bons veiculadores deste fungo. Neste trabalho os referidos substratos, após terem sido acondicionados em tambores plásticos com 40 litros de capacidade, foram fumigados com brometo de meti Ia, posteriormente inoculados com uma suspensão de esporos do antagonista (2,0 x 107 esporos/ml) e incubados sob temperatura ambiente 60 dias antes do plantio
Antibacterial and antifungal activity of a new solvent-cast film based on a functionalized elastin-like polymer
A synthetic biology approach for the development of recombinant protein-based polymers exhibiting antimicrobial properties
The search for advanced materials, especially for those bioinspired, has recently been the focus of
great research in many fields of application. Due to recent advances in materials characterization and
fabrication technologies, and especially through the use of synthetic biology approaches, it is now
possible to reengineer novel functionalities and structures of protein-based materials, taking advantage
of their extreme versatility and applicability.
Antimicrobial peptides (AMPs) are small molecules that occur as part of the innate defense mechanism
in many organisms, even in microbes and virus. The combination of AMPs with recombinant protein-based polymers can be explored for the development of advanced medical devices, to overcome
infections and biofilm formation. In this work, we describe the design, biolog ical production and
processing of a protein-based-polymer comprising a functional domain based on a synthetic cationic
AMP, fused in frame with an elastin-like-polymer consisting of 200 repeats of VPAVG (A200), as
structural unit. The functionalized protein-based-polymer was produced in Escherichia coli and further
purified by exploring the thermoresponsiveness property of poly-VPAVG.
Free standing films, especially thinking in downstream processing for application as thin film coating of
medical devices, were obtained by solvent-cast. The antibacterial and antifungal activities of cast films
were tested against different bacterial and fungal species, both in vitro and ex vivo. The recombinant
AMP:A200 biopolymer showed high growth inhibition against a wide range of bacterial species, both
gram positive and negative, and yeast species. The antimicrobial activity was time dependent of
exposition and remarkably, in some bacterial species, almost 100% of cell death was detected after 30
minutes of cell suspension in contact with cast films.This work was financially supported Portuguese funding from FEDER through POFC – COMPETE and PEst project C-BIA-UI4050-2011 (Portugal). AC and RM acknowledge FCT for SFRH-BD-75882-2011 and SFRH-BPD-86470-2012 grants, respectively
Monitoramento dos atributos físico-químicos do solo e proposições de fertilização em área de Cynodon dactylon sobressemeado com forrageiras de inverno.
Emissão de óxido nitroso derivada do cultivo de feijoeiro comum (3ª safra) seguido de milho em latossolo de cerrado.
o presente estudo objetivou quantificar a emissão do óxido nitroso do solo sob a cultura do feijoeiro comum irrigado (terceira safra) e sob milho (safra de verão) em plantio direto, em Santo Antônio de Goiás, GO
- …