Kundu, S, Feio G, Pinto LFV, Almeida PL, Figueirinhas JL, Godinho MH.
2010.
Deuterium NMR Study of Orientational Order in Cellulosic Network Microfibers. Macromolecules. 43:5749-5755., Number 13
AbstractDeuterium NMR was used to investigate the orientational order in a composite cellulosic formed by liquid crystalline acetoxypropylcellulose (A PC) and demented nematic 4'-penty1-4-cyanobiphenyl (5CB-4 alpha d(2)) with the per centage of 85% A PC by weight Three forms of the composite including electro spun microfibers, thin film and bulk samples were analyzed The NMR results initially suggest two distinct scenarios, one whet e the 503-alpha d(2), is confined to small droplets with dimensions smaller than the magnetic coherence length and the other where the 503-alpha d(2) molecules arc aligned with the A PC network chains Polarized optical microscopy (POW from thin film samples along with all the NMR results show the presence of 5CB-alpha d(2) droplets in the composite systems with a nematic wetting layer at the APC-5CB-alpha d(2) interface that experiences and order disorder transition driven by the polymer network N-I transition The characterization of the APC network I-N transition shows a pronounced subcritical behavior within a heterogeneity scenario
Ribeiro, T, Santos-Silva T, Alves VD, Dias FMV, Luis AS, Prates JAM, Ferreira LMA, Romao MJ, Fontes CMGA.
2010.
Family 42 carbohydrate-binding modules display multiple arabinoxylan-binding interfaces presenting different ligand affinities. Biochimica Et Biophysica Acta-Proteins and Proteomics. 1804:2054-2062., Number 10
Abstractn/a
Matos, C, Ortigueira MD.
2010.
Fractional Filters: An Optimization Approach. Emerging Trends in Technological Innovation. 314:361–366.
AbstractThe design and optimization of fractional filters is considered in this paper. Some of the classic filter architectures are presented and their performances relatively to an ideal amplitude spectrum evaluated. The fractional filters are designed using the differential evolution optimization algorithm for computing their parameters. To evaluate the performances of all the filters the quadratic error between the computed amplitude is calculated against an ideal (goal) response. The fractional filters have a better behavior, both in the pass and reject-band.
Ortigueira, MD.
2010.
The fractional quantum derivative and its integral representations? Communications in Nonlinear Science and Numerical Simulation. 15:956–962., Number 4: Elsevier B.V.
AbstractThe quantum fractional derivative is defined using formulations analogue to the common Grünwald?Letnikov derivatives. While these use a linear variable scale, the quantum derivative uses an exponential scale and is defined in R? or R?. Two integral formulations similar to the usual Liouville derivatives are deduced with the help of the Mellin transform.
Bicho, A, Roque ACA, Cardoso AS, Domingos P, Batalha ÍL.
2010.
In vitro studies with mammalian cell lines and gum arabic‐coated magnetic nanoparticles. Journal of Molecular Recognition. 23:536–542., Number 6
AbstractIron oxide magnetic nanoparticles {(MNPs)} were synthesized by the chemical co-precipitation method and coated with gum arabic {(GA)} by physical adsorption and covalent attachment. Cultures of mammalian cell lines {(HEK293}, {CHO} and {TE671)} were grown in the presence of uncoated and {GA-coated} {MNPs.} Cellular growth was followed by optical microscopy in order to assess the proportion of cells with particles, alterations in cellular density and the presence of debris. The in vitro assays demonstrated that cells from different origins are affected differently by the presence of the nanoparticles. Also, the methods followed for {GA} coating of {MNPs} endow distinct surface characteristics that probably underlie the observed differences when in contact with the cells. In general, the nanoparticles to which the {GA} was adsorbed had a smaller ability to attach to the cells' surface and to compromise the viability of the cultures. Copyright © 2010 John Wiley & Sons, Ltd.
Nascimento, B, Batista A, Alves LB, Ortigueira M, Rato R.
2010.
MicroECG: An Integrated Platform for the Cardiac Arrythmia Detection and Characterization. Emerging Trends in Technological Innovation. 314:367–373.
AbstractA software tool for the analysis of the High-Resolution Electrocardiogram (HR-ECG) for Arrhythmia detection is introduced. New algorithms based on Wavelet analysis are presented and compared with the classic Simson protocol over the P and QRS segments of the Electrocardiogram (EEG). A novel procedure based on a two step wavelet analysis and synthesis is performed in order to obtain a frequency description of the P, T or QRS segments. This frequency ?signature? is useful for the detection of otherwise asymptomatic Arrhythmia patients. The tool has been developed in Matlab, and deployed for a standalone C application.
Abrantes, M, Neves P, Antunes MM, Gago S, Almeida Paz FA, Rodrigues AE, Pillinger M, Goncalves IS, Silva CM, Valente AA.
2010.
Microwave-assisted molybdenum-catalysed epoxidation of olefins. Journal of Molecular Catalysis a-Chemical. 320:19-26., Number 1-2
Abstractn/a
Figueirinhas, JL, Feio G, Cruz C, Lehmann M, Kohn C, Dong RY.
2010.
Nuclear magnetic resonance spectroscopic investigations of phase biaxiality in the nematic glass of a shape-persistent V-shaped mesogen. J Chem Phys. 133:174509., Number 17
AbstractDeuterium and carbon-13 NMR spectroscopy were used to study both the high temperature uniaxial nematic and the low temperature biaxial nematic glass of a shape-persistent V-shaped mesogen. It was found that biaxial ordering determined in the domains of the latter has symmetry lower than D(2h) and is compatible with C(2h) symmetry or lower. In particular, elements of the ordering matrix including biaxial phase order parameters were determined from (2)H NMR at two temperatures, one just below the glass transition, and the other deep inside the biaxial glass, which allowed for the characterization of the dominant molecular motions at these temperatures. (13)C NMR magic angle spinning sideband patterns, collected both in the high temperature nematic phase and in the nematic glass, clearly show the difference between them in terms of the phase symmetry.
Ortigueira, MD.
2010.
On the Fractional Linear Scale Invariant Systems. IEEE Transactions on Signal Processing. 58:6406–6410., Number 12
AbstractThe linear scale invariant systems are introduced for both integer and fractional orders. They are defined by the generalized Euler-Cauchy differential equation. The quantum fractional derivatives are suitable for dealing with this kind of systems, allowing us to define impulse response and transfer function with the help of the Mellin transform. It is shown how to compute the impulse responses corresponding to the two half plane regions of convergence of the transfer function.
Gomes, R, Batista A, Ortigueira M, Rato R, Baldeiras M.
2010.
Railscan: A Tool for the Detection and Quantification of Rail Corrugation. Emerging Trends in Technological Innovation. 314:401–408.
AbstractRail corrugation is a phenomenon that leads to a waving in the rails with wavelengths typically between 3 cm and 100 cm and amplitude levels of several microns. The genesis of this waving is complex. Rail corrugation is a recognized problem that leads to excess vibration on the rails and vehicles to a point of reducing their life span and compromising safety. In urban areas excess vibration noise is also a problem. A software tool was developed to analyze accelerometer signals acquired in the boggies of rail vehicles in order to quantify the rail corrugation according to their frequency and amplitude. A wavelet packet methodology was used in this work and compared with the One Third Octave Filter (OTOF) power representations, which is currently used in the industry. It is shown that the former produces better results.