A systematic study of the electrochromic (EC) behavior of electropolymerized poly[M(salen)] films (M = Ni, Cu, and Pd) was performed by spectroelectrochemistry. Color contrast between oxidized and reduced states, stability under square wave potential cycling, coloration efficiency, and switching rate were evaluated. Five polymers were selected to assemble solid-state EC cells in a symmetrical configuration (electrode/poly[M(salen)] film/opaque electrolyte/poly[M(salen)] film/electrode). The best EC performance was found for poly[Pd(3-Mesalen)], poly[1], with 38% of initial diffuse reflectance variation and loss of 50% after 6769 cycles. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3457474] All rights reserved.

Flexible, transparent and self-supporting electrolyte films based on poly(trimethylene carbonate)/poly(ethylene oxide) (p(TMC/PEO) interpenetrating networks doped with LiClO(4) were prepared by the solvent casting technique. These novel solid polymer electrolyte (SPE) systems were characterized by measurements of conductivity, cyclic voltammetry, differential scanning calorimetry and thermogravimetry. The incorporation of solid electrolytes as components of electrochromic devices can offer certain operational advantages in real-world applications. In this study, all-solid-state electrochromic cells were characterized, using Prussian blue (PB) and poly-(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT) as complementary electrochromic compounds on poly(ethyleneterphthalate) (PET) coated with indium tin oxide (ITO) as flexible electrodes. Assembled devices with PET/ITO/PB/SPE/PEDOT/ITO/PET "sandwich-like" structure were assembled and successfully cycled between light and dark blue, corresponding to the additive optical transitions for PB and PEDOT electrochromic layers. The cells required long cycle times (>600 s) to reach full color switch and have modest stability towards prolonged cycling tests. The use of short duration cycling permitted the observation of changes in the coloration-bleaching performance in cells with different electrolyte compositions. (C) 2009 Elsevier Ltd. All rights reserved.

We report a spectroscopic study of the network of reactions of a flavylium dye encapsulated in the one-dimensional channels of zeolite L. The positively charged 7,4'-dihydroxyflavylium (AH(+)) is easily incorporated and remains stable in zeolite L channels. Once encapsulated, the flavylium exhibits a red shift in the excitation spectrum comparative to aqueous solutions. Moreover, contrary to the observed behavior in water, no excited state proton transfer takes place in the loaded crystals, corroborating the encapsulation of AH(+). The trans-chalcone (Ct) form from the same flavylium network could also be encapsulated inside the zeolite L, using toluene with 20% triethylamine as solvent and K(+) as counter ion of the negative framework of the zeolite. The encapsulation of Ct is confirmed by changes on the excitation spectrum and by a blue shift in the emission. The encapsulated Ct was shown to generate AH(+) when the Ct-loaded crystals were suspended in water, which proves that isomerization, tautomerization and dehydration reactions take place inside the zeolite L.

The effect of kefir grains on the proteolysis of major milk proteins in milk kefir and in a culture of kefir grains in pasteurized cheese whey was followed by reverse {phase-HPLC} analysis. The reduction of kappa-, alpha-, and beta-caseins {(CN)}, alpha-lactalbumin {(alpha-LA)}, and beta-lactoglobulin {(beta-LG)} contents during 48 and 90 h of incubation of pasteurized milk {(100mL)} and respective cheese whey with kefir grains (6 and 12 g) at 20 degrees C was monitored. Significant proteolysis of {alpha-LA} and kappa-, alpha-, and beta-caseins was observed. The effect of kefir amount (6 and 12 {g/100mL)} was significant for {alpha-LA} and alpha- and {beta-CN.} {alpha-Lactalbumin} and {beta-CN} were more easily hydrolyzed than {alpha-CN.} No significant reduction was observed with respect to {beta-LG} concentration for 6 and 12 g of kefir in {100mL} of milk over 48 h, indicating that no significant proteolysis was carried out. Similar results were observed when the experiment was conducted over 90 h. Regarding the cheese whey kefir samples, similar behavior was observed for the proteolysis of {alpha-LA} and {beta-LG:} {alpha-LA} was hydrolyzed between 60 and 90% after 12h (for 6 and 12 g of kefir) and no significant {beta-LG} proteolysis occurred. The proteolytic activity of lactic acid bacteria and yeasts in kefir community was evaluated. Kefir milk prepared under normal conditions contained peptides from proteolysis of {alpha-LA} and kappa-, alpha-, and beta-caseins. Hydrolysis is dependent on the kefir:milk ratio and incubation time. {beta-Lactoglobulin} is not hydrolyzed even when higher hydrolysis time is used. Kefir grains are not appropriate as adjunct cultures to increase {beta-LG} digestibility in whey-based or whey-containing foods.

The alternative system initial conditions versus the derivative initial conditions is focused in this paper. It is shown that Riemann?Liouville and Caputo initial conditions result from the corresponding derivative and not necessarily from the system at hand. To setup the correct system initialization, a formulation generalizing the integer order approach is presented. This is based on a generalization to the fractional environment of the well known jump formula. The obtained scheme is very general and does not depend on any transform. Besides, it can also be used in the time variant case. The Riemann?Liouville and Caputo initial conditions are interpreted in terms of this general framework and deduced equations where they are correct.

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The project started in 2009 with the support of DAAD in Germany and CRUP in Portugal under the “Collaborative German-Portuguese University Actions” programme. One central goal is the further development of a theory of technology assessment applied to robotics and autonomous systems in general that reflects in its methodology the changing conditions of knowledge production in modern societies and the emergence of new robotic technologies and of associated disruptive changes. Relevant topics here are handling broadened future horizons and new clusters of science and technology (medicine, engineering, interfaces, industrial automation, micro-devices, security and safety), as well as new governance structures in policy decision making concerning research and development (R&D).

High blood pressure or hypertension is a condition affecting many individuals and represents a controllable risk factor for cardiovascular diseases such as coronary heart disease and stroke. A non-pharmacological approach to manage these includes the application of food components with antihypertensive activity. Milk protein-derived peptides have been exploited as natural hypotensive agents, namely the peptides {Val-Pro-Pro} {(VPP)} and {Ile-Pro-Pro} {(IPP)}, already commercialized in functional foods as a potential alternative to synthetic drugs. These bioactive peptides inhibit in vitro and in vivo the Angiotensin I-converting enzyme {(ACE)}, a protein with an important role in blood pressure regulation. In this work, we attempted to elucidate the possible mode of interaction between the peptides and {ACE}, including mechanisms of binding to the cofactor Zn2+, and further contrast this with the known mode of inhibition exerted by synthetic drugs {(Captopril}, Enalaprilat and Lisinopril). The bioactive peptide {Ala-Leu-Pro-Met-His-Ile-Arg} {(ALPMHIR)}, also known to inhibit the enzyme {ACE} but with a lower efficiency than {VPP} and {IPP}, was utilized in the docking studies for comparison. It was observed that the best docking poses obtained for {VPP} and {IPP} were located at the {ACE} catalytic site with very high resemblance to the drugs mode of interaction, including the coordination with Zn2+. As for {ALPMHIR}, the best docking poses were located in the narrow {ACE} channel outside the catalytic site, representing higher affinity energies and fewer resemblances with the interaction established by drugs.

The syntheses, thermodynamic and kinetic properties of a series of 2-styryl-1-benzopyrylium compounds are reported. This family of compounds was found to follow the same pH- and light-dependent network of chemical reactions previously described for flavylium (2-phenyl-1-benzopyrylim) compounds. However, 2-styryl-1-benzopyrylium compounds exhibit absorption spectra substantially red shifted when compared with flavylium analogues (up to 90 nm). In particular, a photochromic system switching from yellow to light blue based on derivatives of natural anthocyanins is for the first time documented. (C) 2008 Elsevier Ltd. All rights reserved.

The project started in 2009 with the support of DAAD in Germany and CRUP in Portugal under the “Collaborative German-Portuguese University Actions” programme. One central goal is the further development of a theory of technology assessment applied to robotics and autonomous systems in general that reflects in its methodology the changing conditions of knowledge production in modern societies and the emergence of new robotic technologies and of associated disruptive changes. Relevant topics here are handling broadened future horizons and new clusters of science and technology (medicine, engineering, interfaces, industrial automation, micro-devices, security and safety), as well as new governance structures in policy decision making concerning research and development (R&D).

The project started in 2009 with the support of DAAD in Germany and CRUP in Portugal under the “Collaborative German-Portuguese University Actions” programme. One central goal is the further development of a theory of technology assessment applied to robotics and autonomous systems in general that reflects in its methodology the changing conditions of knowledge production in modern societies and the emergence of new robotic technologies and of associated disruptive changes. Relevant topics here are handling broadened future horizons and new clusters of science and technology (medicine, engineering, interfaces, industrial automation, micro-devices, security and safety), as well as new governance structures in policy decision making concerning research and development (R&D).

We assembled a new electrospinning apparatus and used poly(ethylene oxide) as a model polymer to perform a systematic study on the influence of solution and processing parameters on the morphology of electrospun nanofibers. Solution parameters studied were polymer concentration and molecular mass. The solvent used, 60 wt% water,40 wt% ethanol, was the same throughout the study. Processing parameters analyzed were: solution feed rate, needle tip-collector distance and electrostatic potential difference between the needle and collector. Solution viscosity increased both with polymer concentration and molecular mass. Polymer concentration plays a decisive role on the outcome of the electrospinning process: a low concentration led to the formation of beaded fibers; an intermediate concentration yielded good quality fibers; a high concentration resulted in a bimodal size distribution and at even higher concentration a distributed deposition. Fiber diameter increased with polymer molecular mass and higher molecular masses are associated with a higher frequency of splaying events. Fiber diameter increased linearly with solution feed rate. While an increase in needle-collector distance represents a weaker electric field, a greater distance to be covered by the fibers and a longer flight time, presumably favoring the formation of thinner fibers, as solvent evaporation leads to a local increase of concentration and viscosity, viscoelastic forces opposing stretching caused an increase of fiber diameter with needle-collector distance. A higher voltage applied at the needle is associated with a higher charging of the polymer and a higher electrical current through it ultimately leading to incomplete solvent evaporation and merged fibers being produced. Controlling the charging of the polymer independently of the electric field strength was achieved by applying a voltage to the collector while distance and potential difference were kept constant. The increased electrostatic repulsion associated with an increase of the high voltage applied to the needle led to the disappearance of merged fibers.