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2013
Simão, J, Rameshan N, Veiga L.  2013.  Resource-Aware Scaling of Multi-threaded Java Applications in Multi-tenancy Scenarios, dec. IEEE CloudCom 2013. : IEEE Abstract2013-cloudcom-simao-b.pdf

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Vilas-Boas, V, Silva R, Palmeira A, Sousa E, Ferreira LM, Branco PS, Carvalho F, de Bastos ML, Remiao F.  2013.  Development of Novel Rifampicin-Derived P-Glycoprotein Activators/Inducers. Synthesis, In Silico Analysis and Application in the RBE4 Cell Model, Using Paraquat as Substrate, AUG 26. PLOS ONE. 8, Number 8 Abstract

P-glycoprotein (P-gp) is a 170 kDa transmembrane protein involved in the outward transport of many structurally unrelated substrates. P-gp activation/induction may function as an antidotal pathway to prevent the cytotoxicity of these substrates. In the present study we aimed at testing rifampicin (Rif) and three newly synthesized Rif derivatives (a mono-methoxylated derivative, MeORif, a peracetylated derivative, PerAcRif, and a reduced derivative, RedRif) to establish their ability to modulate P-gp expression and activity in a cellular model of the rat's blood-brain barrier, the RBE4 cell line P-gp expression was assessed by western blot using C219 anti-P-gp antibody. P-gp function was evaluated by flow cytometry measuring the accumulation of rhodamine123. Whenever P-gp activation/induction ability was detected in a tested compound, its antidotal effect was further tested using paraquat as cytotoxicity model. Interactions between Rif or its derivatives and P-gp were also investigated by computational analysis. Rif led to a significant increase in P-gp expression at 72 h and RedRif significantly increased both P-gp expression and activity. No significant differences were observed for the other derivatives. Pre-or simultaneous treatment with RedRif protected cells against paraquat-induced cytotoxicity, an effect reverted by GF120918, a P-gp inhibitor, corroborating the observed P-gp activation ability. Interaction of RedRif with P-gp drug-binding pocket was consistent with an activation mechanism of action, which was confirmed with docking studies. Therefore, RedRif protection against paraquat-induced cytotoxicity in RBE4 cells, through P-gp activation/induction, suggests that it may be useful as an antidote for cytotoxic substrates of P-gp.

Guerra, M, Parente F, Santos JP.  2013.  Electron impact ionization cross sections of several ionization stages of Kr, Ar and Fe, Aug 15. International Journal of Mass Spectrometry. 348:1-8.: Elsevier B.V. AbstractWebsite

International Journal of Mass Spectrometry, 348 (2013) 1-8. doi:10.1016/j.ijms.2013.02.011

Avo, J, Martins S, Jorge Parola A, Lima JC, Branco PS, Prates Ramalho JP, Pereira A.  2013.  A Family of Styrylcoumarins: Synthesis, Spectroscopic, Photophysical and Photochemical Properties, AUG. CHEMPLUSCHEM. 78:789-792., Number 8 Abstract
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Guerra, M, Amaro P, Szabo CI, Gumberidze A, Indelicato P, Santos JP.  2013.  Analysis of the charge state distribution in an ECRIS Ar plasma using high-resolution x-ray spectra, Apr 01. Journal of Physics B: Atomic, Molecular and Optical Physics. 46:065701., Number 6 AbstractWebsite
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Baltazar, LG, Henriques FMA.  2013.  Performance improvement of hydraulic lime based grouts for masonry consolidation – An experimental study, 25th - 27th June. Proceedings of the 13th International Conference on Studies, Repairs and Maintenance of Heritage Architecture. , New Forest, UK
Jorne, F, Henriques FMA.  2013.  Study of hydraulic lime grout injections in different porous media: an experimental study, 25th - 27th June. Proceedings of the 13th International Conference on Studies, Repairs and Maintenance of Heritage Architecture. , New Forest, UK
Almeida, G, Gonzalez J, Rosado L, Vilaça P, Santos TG.  2013.  Advances in NDT and materials characterization by eddy currents, 2013. 46th CIRP Conference on Manufacturing Systems, CIRP CMS 2013. 7:359-364., Setubal Abstract
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Santos, TG, Fernandes FB, Bernardo G, Miranda RM.  2013.  Analyzing mechanical properties and nondestructive characteristics of brazed joints of NiTi shape memory alloys to carbon steel rods, 2013. International Journal of Advanced Manufacturing Technology. 66(5-8):787-793. AbstractWebsite
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Santos, TG, Faria J, Vilaça P, Miranda RM.  2013.  Application of eddy currents in processed materials structural evaluation, 2013. 6th International Materials Symposium, Materiais 2011. 730-732:715-720., Guimaraes AbstractWebsite
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Rondao, R, de Melo JSS, Pina J, Melo MJ, Vitorino T, Parola AJ.  2013.  Brazilwood Reds: The (Photo)Chemistry of Brazilin and Brazilein, 2013. Journal of Physical Chemistry A. 117:10650-10660. AbstractWebsite

The ground and excited state (in the singlet state, S-1) acid-base equilibria, together with the photophysical properties of the two main constituents of brazilwood, brazilin and brazilein, have been investigated in aqueous solutions in the pH range: -1 < pH < 10. Brazilin is the colorless reduced form of brazilein where three ground and three excited state species (BredHn, with n = 2-4 representing the protonated hydroxyl groups) are observed with two corresponding acidity constants: pK(a1) = 6.6 and pK(a2) = 9.4 (pK(a1)(*) = 4.7 and pK(a2)(*) = 9.9, obtained from the Forster cycle). In the case of brazilein, three ground species (pK(a1) = 6.5 and pK(a2) = 9.5) and four excited state species were identified (again from the Forster cycle: pK(a1)(*) = 3.9 and pK(a2)(*) = 9.8). The colorless species (brazilin) presents a high fluorescence quantum yield (phi(F) = 0.33) and competitive radiative channel (k(F) = 1.3 x 10(9) s(-1)) over radiationless processes (k(NR) = 2.6 x 10(9) s(-1)). In contrast to this behavior, brazilein displays a phi(F) value 2 orders of magnitude lower and a dominance of the radiationless decay pathways, which is suggested to be linked to an excited state proton transfer leading to a quinoidal-like structure. This is further supported by time-resolved data (obtained in a ps time domain). The overall data indicates that brazilin is more prone to degradation than brazilein, mainly due to the high efficiency of the racliationless decay channel (likely through internal conversion), which confers a stabilizing inherent characteristic to the latter. In the case of brazilein, the efficiency of the radiationless channel is linked to an excited state intramolecular proton transfer resulting from an excited state equilibrium involving neutral and zwitterionic tautomeric species of this compound. Furthermore, a theoretical study has been performed with the determination of the optimized ground-state and excited molecular geometries for the two compounds together with the prediction of the lowest vertical one-electron excitation energy and the relevant molecular orbital contours and charge densities changes using density functional theory calculations. These were found to corroborate differences in acidity in the ground and excited states.

Geng, Y, Almeida PL, Fernandes SN, Cheng C, Palffy-Muhoray P, Godinho MH.  2013.  A cellulose liquid crystal motor: a steam engine of the second kind, 2013. 3(1):1028. AbstractWebsite

The salient feature of liquid crystal elastomers and networks is strong coupling between orientational order and mechanical strain. Orientational order can be changed by a wide variety of stimuli, including the presence of moisture. Changes in the orientation of constituents give rise to stresses and strains, which result in changes in sample shape. We have utilized this effect to build soft cellulose-based motor driven by humidity. The motor consists of a circular loop of cellulose film, which passes over two wheels. When humid air is present near one of the wheels on one side of the film, with drier air elsewhere, rotation of the wheels results. As the wheels rotate, the humid film dries. The motor runs so long as the difference in humidity is maintained. Our cellulose liquid crystal motor thus extracts mechanical work from a difference in humidity.

Avo, J, Martins S, Parola AJ, Lima JC, Branco PS, Ramalho JPP, Pereira A.  2013.  A Family of Styrylcoumarins: Synthesis, Spectroscopic, Photophysical and Photochemical Properties, 2013. Chempluschem. 78:789-792. AbstractWebsite
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Rosado, LS, Gonzalez JC, Santos TG, Ramos PM, Piedade M.  2013.  Geometric optimization of a differential planar eddy currents probe for non-destructive testing, 2013. Sensors and Actuators, A: Physical. 197:96-105. AbstractWebsite
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Gago, S, Fonseca IM, Parola AJ.  2013.  Hybrid mesoporous silica grafted with photoisomerizable 2-hydroxychalcones, 2013. Microporous and Mesoporous Materials. 180:40-47. AbstractWebsite

Hybrid photochromic mesoporous materials based on MCM-41 and SBA-15 were synthesized by covalent attachment of 3'-butoxy-7-hydroxyflavylium (Fl-OH) and 3'-butoxy-7-metoxyflavylium (Fl-OCH3) hydrogensulfates. The pristine materials were initially grafted with 3-chloropropyl groups, reacted with 3'-hydroxyacetophenone and finally condensed with appropriate salicylaldehydes to yield the new hybrids MCM-41-Fl-OH and SBA-15-Fl-OCH3. The materials were characterized by powder X-ray diffraction, N-2 adsorption, solid-state C-13 CPMAS NMR spectroscopy, and thermogravimetric and elemental analyses, which confirm the successful covalent bonding of the flavylium moieties with loadings of 16.90 +/- 0.05% and 11.78 +/- 0.04% (w/w) for MCM-41-Fl-OH and SBA-15-OCH3, respectively. Flavylium compounds originate in solution a multiequilibria reaction network than can be actuated by pH and light, defining pH-coupled photochromic systems. The new hybrids show pH-dependent reflectance spectra resembling those observed in solution, but shifted to higher pH ranges, indicating a higher stability of the grafted flavylium cations. Irradiation of these materials equilibrated at adequate pH values where the photoisomerizable trans-chalcones predominate shows formation of the respective flavylium cations that recover back to the initial compositions upon standing in the dark, leading these new organic-inorganic hybrids as pH-dependent photochromic materials. (C) 2013 Elsevier Inc. All rights reserved.

Leydet, Y, Batat P, Jonusauskas G, Denisov S, Lima JC, Parola AJ, McClenaghan ND, Pina F.  2013.  Impact of Water on the Cis-Trans Photoisomerization of Hydroxychalcones, 2013. Journal of Physical Chemistry A. 117:4167-4173. AbstractWebsite

The photochromism of a 2-hydroxychalcone has been studied in CH3CN and H2O/CH3OH (1/1, v/v), as well as in analogous deuterated solvents using steady-state (UV-vis absorption, H-1 and C-13 NMR) and time-resolved (ultrafast transient absorption and nanosecond flow flash photolysis) spectroscopies. Whereas the irradiation of trans-chalcone (Ct) under neutral pH conditions leads to the formation of the same final chromene derivative (B) in both media, two distinct photochemical mechanisms are proposed in agreement with thermodynamic and kinetic properties of the chemical reaction network at the ground state. Following light excitation, the first steps are identical in acetonitrile and aqueous solution: the Franck-Condon excited state rapidly populates the trans-chalcone singlet excited state (1)Ct* (LE), which evolves into a twisted state P-1*. This excited state is directly responsible for the photochemistry in acetonitrile in the nanosecond time scale (16 ns) leading to the formation of cis-chalcone (Cc) through a simple isomerization process. The resulting cis-chalcone evolves into the chromene B through a tautomerization process in the ground state (tau= 10 ms). Unlike in acetonitrile, in H2O/CH3OH (1/1, v/v), the P* state becomes unstable and evolves into a new state attributed to the tautomer (1)Q*. This state directly evolves into B in one photochemical step through a consecutive ultrafast tautomerization process followed by electrocyclization. This last case represents a new hypothesis in the photochromism of 2-hydroxychalcone derivatives.

Petrov, V, Diniz AM, Cunha-Silva L, Parola AJ, Pina F.  2013.  Kinetic and thermodynamic study of 2 '-hydroxy-8-methoxyflavylium. Reaction network interconverting flavylium cation and flavanone, 2013. Rsc Advances. 3:10786-10794. AbstractWebsite

2'-Hydroxyflavylium and 2'-hydroxyflavanone derivatives can be interconverted by a precise sequence of pH jumps, through the respective intermediate (mono) ionized trans-chalcones. In acidic and neutral media, the well known network of chemical reactions involving flavylium cation, quinoidal base, hemiketal, and cis and trans chalcones is established. In the pH range 8 < pH < 10, the chalcone (Ct) deprotonates and evolves to the formation of a flavanone (F). At higher pH values, the di-ionized trans-chalcone is the stable species, formed from the flavylium cation. Acidification of the di-ionized trans-chalcone gives the flavylium cation or the flavanone, via the mono-ionized trans-chalcone, respectively at pH < 1 and pH approximate to 9. In contrast with the chalcones, the flavanone once formed is stable even in acidic media. However, under strongly basic conditions, it leads back to the di-ionized trans-chalcone, the most stable species at more basic pH values, and the reactions leading to Ct(-), F, Ct(2-), Ct(-), constitute a one direction cycle for interconversion of these species.

Geng, Y, Seč D, Almeida PL, Lavrentovich OD, Žumer S, Godinho MH.  2013.  Liquid crystal necklaces: cholesteric drops threaded by thin cellulose fibres, 2013. Soft Matter. 9(33):7928-7933.: The Royal Society of Chemistry AbstractWebsite

Liquid crystals in confined geometries exhibit numerous complex structures often including topological defects that are controlled by the nematic elasticity, chirality and surface anchoring. In this work, we study the structures of cholesteric droplets pierced by cellulose fibres with planar anchoring at droplet and fibre surfaces. By varying the temperature we demonstrate the role of twisting power and droplet diameter on the equilibrium structures. The observed structures are complemented by detailed numerical simulations of possible director fields decorated by defects. Three distinct structures, a bipolar and two ring configurations, are identified experimentally and numerically. Designing cholesteric liquid crystal microdroplets on thin long threads opens new routes to produce fibre waveguides decorated with complex microresonators.

Coutinho, ML, Miller AZ, Gutierrez-Patricio S, Hernandez-Marine M, Gomez-Bolea A, Rogerio-Candelera MA, Philips AJL, Jurado V, Saiz-Jimenez C, Macedo MF.  2013.  Microbial communities on deteriorated artistic tiles from Pena National Palace (Sintra, Portugal), 2013. International Biodeterioration and Biodegradation. 84:322-332. AbstractWebsite
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Martins, P, Rosa D, and Baptista AFPRV.  2013.  Nanoparticle Drug Delivery Systems: Recent Patents and Applications in Nanomedicine, 2013. 3(2):105-118. Abstract

Traditional methods of drug delivery present several drawbacks, mainly due to off-target effects that mayoriginate severe side and toxic effect to healthy tissues. Parallel to the development of novel more effective drugs,
particular effort has been dedicated to develop and optimize drug delivery vehicles capable of specifically targeting the
required tissue/organ and to deliver the cargo only where and when it is needed. New drug delivery systems based on
nanoscale devices showing new and improved pharmacokinetic and pharmacodynamics properties like enhanced
bioavailability, high drug loading or systemic stability have surged in the past decade as promising solutions to the
required therapeutic efficacy. Amongst these nanoscale vectors, nanoparticles for drug delivery, such as polymeric, lipidbased,
ceramic or metallic nanoparticles, have been at the forefront of pharmaceutical development. The interest in
nanomedicine for treatment and diagnosis is clearly reflected on the increasing number of publications and issued patents
every year. Here, we provide a broad overview of novel nanoparticle based drug delivery systems, ranging from
polymeric systems to metal nanoparticles, while simultaneously listing the most relevant related patents.

Miranda, RM, Santos TG, Gandra J, Lopes N, Silva RJC.  2013.  Reinforcement strategies for producing functionally graded materials by friction stir processing in aluminium alloys, 2013. Journal of Materials Processing Technology. 213(9):1609-1615. AbstractWebsite
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Oliveira, J, da Silva MA, Jorge Parola A, Mateus N, Bras NF, Ramos MJ, de Freitas V.  2013.  Structural characterization of a A-type linked trimeric anthocyanin derived pigment occurring in a young Port wine, 2013. Food Chemistry. 141:1987-1996. Abstract
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Calogero, G, Sinopoli A, Citro I, Di Marco G, Petrov V, Diniz AM, Parola AJ, Pina F.  2013.  Synthetic analogues of anthocyanins as sensitizers for dye-sensitized solar cells, 2013. Photochemical & Photobiological Sciences. 12:883-894. AbstractWebsite

Seven flavylium salt dyes were employed for the first time as sensitizers for dye-sensitized solar cells (DSSCs). The theoretical and experimental wavelengths of the maximum absorbances, the HOMO and LUMO energy levels, the coefficients, the oscillator strengths and the dipole moments are calculated for these synthetic dyes. The introduction of a donor group in the flavylium molecular structure was investigated. Photophysical and photoelectrochemical measurements showed that some of these synthetic analogues of anthocyanins are very promising for DSSC applications. The best performance was obtained by a DSSC based on the novel compound 7-(N,N-diethylamino)-3',4'-dihydroxyflavylium which produced a 2.15% solar energy-to-electricity conversion efficiency, under AM 1.5 irradiation (100 mW cm(-2)) with a short-circuit current density (J(sc)) of 12.0 mA cm(-2), a fill factor of 0.5 and an open-circuit voltage (V-oc) of 0.355 V; its incident photocurrent efficiency of 51% at the peak of the visible absorption band of the dye is remarkable. Our results demonstrated that the substitution of a hydroxylic group with a diethylamine unit in position 7 of ring A of the flavylium backbone expanded the pi-conjugation in the dye and thus resulted in a higher absorption in the visible region and is advantageous for effective electron injection from the dye into the conduction band of TiO2.

Pacheco, MF, Pereira AI, Branco LC, Parola AJ.  2013.  Varnish removal from paintings using ionic liquids, 2013. Journal of Materials Chemistry A. 1:7016-7018. AbstractWebsite

The possibility of replacing volatile and toxic organic solvents by ionic liquids (ILs) could contribute to safer procedures for conservation and restoration. This study introduces the use of ILs in varnish removal from paintings. The efficacy of this new procedure was assessed by applying different types of ILs in mock-ups of several painting materials and varnishes. The removal of IL residues from the surface of paintings was assessed mainly by FTIR-ATR. The application of ILs to a real painting is illustrated.

Geng, Y, Almeida PL, Feio GM, Figueirinhas JL, Godinho MH.  2013.  Water-Based Cellulose Liquid Crystal System Investigated by Rheo-NMR, 2013. MacromoleculesMacromolecules. 46(11):4296-4302.: American Chemical Society AbstractWebsite

Water-based cellulose cholesteric liquid crystalline phases at rest can undergo structural changes induced by shear flow. This reflects on the deuterium spectra recorded when the system is investigated by rheo-nuclear magnetic resonance (rheo-NMR) techniques. In this work, the model system hydroxypropylcellulose (HPC)+water is revisited using rheo-NMR to clarify unsettled points regarding its behavior under shear and in relaxation. The NMR spectra allow the identification of five different stable ordering states, within shear and relaxation, which are well integrated in a mesoscopic picture of the system’s structural evolution under shear and relaxation. This picture emerging from the large body of studies available for this system by other experimental techniques, accounts well for the NMR data and is in good agreement with the three distinct regions of steady shear flow recognized for some lyotropic LC polymers. Shear rates in between 0.1 and 1.0 s–1 where investigated using a Taylor–Couette flow and deuterated water was used as solvent for the deuterium NMR (DNMR) analysis.Water-based cellulose cholesteric liquid crystalline phases at rest can undergo structural changes induced by shear flow. This reflects on the deuterium spectra recorded when the system is investigated by rheo-nuclear magnetic resonance (rheo-NMR) techniques. In this work, the model system hydroxypropylcellulose (HPC)+water is revisited using rheo-NMR to clarify unsettled points regarding its behavior under shear and in relaxation. The NMR spectra allow the identification of five different stable ordering states, within shear and relaxation, which are well integrated in a mesoscopic picture of the system’s structural evolution under shear and relaxation. This picture emerging from the large body of studies available for this system by other experimental techniques, accounts well for the NMR data and is in good agreement with the three distinct regions of steady shear flow recognized for some lyotropic LC polymers. Shear rates in between 0.1 and 1.0 s–1 where investigated using a Taylor–Couette flow and deuterated water was used as solvent for the deuterium NMR (DNMR) analysis.

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