Abstract The knowledge on the binding of vanadium ions and complexes to serum proteins and how vanadium might be transported in blood and up-taken by cells has received much attention during the last decade, particularly as far as the transport of VIVO2+ is concerned. In this work we revise and discuss some relevant aspects of previous research, namely the two main types of binding proposed for transport of VIVO(carrier)2 complexes. New results, obtained by circular dichroism (CD), \{EPR\} and gel electrophoresis, regarding the binding of vanadium to hTF in the oxidation states +5 and +3 are also presented. Namely, evidences for the binding of VV-species to diferric-transferrin, designated by (FeIII)2hTF, as well as to (AlIII)2hTF, are presented and discussed, the possibility of up-take of vanadate by cells through (FeIII)2hTF endocytosis being suggested. It is also confirmed that \{VIII\} binds strongly to hTF, forming di-vanadium(III)-transferrin, designated by (VIII)2hTF, and gel electrophoresis experiments indicate that (VIII)2hTF corresponds to a ‘closed conformation’ similar to (FeIII)2hTF.

A novel method to prepare silica nano-sized particles incorporating polyoxometalates was developed leading to a new efficient heterogeneous oxidative catalyst. Zinc-substituted polyoxotungstate [PW11Zn(H2O)O39](5-) (PW11Zn) was encapsulated into silica nanoparticles using a cross-linked organic-inorganic core, performed through successive spontaneous reactions in water. The potassium salt of PW11Zn and the composite formed, PW11Zn-APTES@SiO2, were characterized by a myriad of solid-state methods such as FT-IR, FT-Raman, (31)P and (13)C CP/MAS solid-state NMR, elemental analysis and SEM-EDS, confirming the integrity of the PW11Zn structure immobilized in the silica nanoparticles. The new composite has shown to be a versatile catalyst for the oxidation of olefins and also to catalyze the desulfurization of a model oil using H2O2 as the oxidant and acetonitrile as the solvent. The novel composite material was capable of being recycled without significant loss of activity and maintaining its structural stability for consecutive desulfurization and olefin oxidative cycles.

The design of small interfering RNA (siRNA) delivery materials showing efficacy in vivo is at the forefront of nanotherapeutics research. Polyurea (PURE-type) dendrimers are 'smart' biocompatible 3D polymers that unveil a dynamic and elegant back-folding mechanism involving hydrogen bonding between primary amines at the surface and tertiary amines and ureas at the core. Similarly, to a biological proton pump, they are able to automatically and reversibly transform their conformation in response to pH stimulus. Here, we show that PURE-G4 is a useful gene silencing platform showing no cellular toxicity. As a proof of concept we investigated the PURE-G4-siRNA dendriplex, which was shown to be an attractive platform with high transfection efficacy. The simplicity associated with the complexation of siRNA with polyurea dendrimers makes them a powerful tool for efficient cytosolic siRNA delivery.

Gold nanoparticles (AuNPs) exhibit unique properties that have made them a very attractive material for application in biological assays. Given the potentially interesting interactions between AuNPs and biological macromolecules, we investigated AuNPs-induced protein crystal growth. Differently functionalized AuNPs were tested as additives in cocrystallization studies with model proteins (hen egg white lysozyme (HEWL), ribonuclease A (RNase A), and proteinase K) as well as with case studies where there were problems in obtaining well-diffracting crystals. Trials were performed considering different crystallization drawbacks, from total absence of crystals to improvement of crystal morphology, size, twinning, and number of crystals per drop. Improvement of some of these factors was observed in the cases of HEWL, RNase A, phenylalanine hydroxylase (PAR), myoglobin, native aldehyde oxidase (AOH), and human albumin. In these proteins, the presence of the AuNPs promoted an increase in the size and/or better crystal morphology. From the systematic trials and subsequent observations, it can be concluded that the introduction of AuNPs should definitely be considered in crystal optimization trials to improve previously determined crystallization conditions.

This paper presents the performance of a passive planar rhombic micromixer with diamond-shaped obstacles and a rectangular contraction between the rhombi. The device was experimentally optimized using water for high mixing efficiency and a low pressure drop over a wide range of Reynolds numbers (Re = 0.1–117.6) by varying geometrical parameters such as the number of rhombi, the distance between obstacles and the contraction width. Due to the large amount of data generated, statistical methods were used to facilitate and improve the results of the analysis. The results revealed a rank of factors influencing mixing efficiency: Reynolds number {\textgreater} number of rhombi {\textgreater} contraction width {\textgreater} inter-obstacles distance. The pressure drop measured after three rhombi depends mainly on Re and inter-obstacle distance. The resulting optimum geometry for the low Re regime has a contraction width of 101 $μ$m and inter-obstacles distance of 93 $μ$m, while for the high Re regime a contraction width of 400 $μ$m and inter-obstacle distance of 121 $μ$m are more appropriate. These mixers enabled 80{%} mixing efficiency creating a pressure drop of 6.0 Pa at Re = 0.1 and 5.1 × 104 Pa at Re = 117.6, with a mixer length of 2.5 mm. To the authors' knowledge, the developed mixer is one of the shortest planar passive micromixers reported to date.

The present work reports the synthesis of zinc oxide (ZnO) nanostructures produced either under microwave irradiation using low cost domestic microwave equipment or by conventional heating, both under hydrothermal conditions. X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, room/low temperature photoluminescence, and Raman spectroscopy have been used to investigate the structure, morphology, and optical properties of the produced ZnO nanorods. Identical structures with aspect ratio up to 13 have been achieved for both synthesis routes displaying similar final properties. The hexagonal wurtzite structure has been identified, and a red-orange emission has been detected in the presence of UV irradiation for all the conditions studied. Thermal stability of the as-prepared nanostructures has been evaluated through thermogravimetric measurements revealing an increase of superficial defects. The as-prepared ZnO nanorods were tested as UV sensors on paper substrate, which led to fast response (30 s) and rapid recovery (100 s) times, as well as sensitivity up to 10 indicating that these materials may have a high potential in low cost, disposable UV photodetector applications.

This protocol describes the synthesis and detailed calibration of a gold nanoparticle-based nanobeacon (Au-nanobeacon) as an innovative theranostic approach for detection and inhibition of sequence-specific DNA and RNA for in vitro and ex vivo applications. Under hairpin configuration, proximity to gold nanoparticles leads to fluorescence quenching; hybridization to a complementary target restores fluorescence emission due to the gold nanobeacons’ conformational reorganization that causes the fluorophore and the AuNP to part from each other. This concept can easily be extended and adapted to assist the in vitro evaluation of silencing potential of a given sequence to be later used for ex vivo gene silencing and RNAi approaches, with the ability to monitor real-time gene delivery action. The time range for the entire protocol is  8 days, including synthesis, functionalization and calibration of Au-nanobeacons, RNAi and gene silencing assays.

The potential of a single molecular nanoconjugate to intersect all RNA pathways: from gene specific downregulation to silencing the silencers, i.e. siRNA and miRNA pathways, is demonstrated. Gold-nanobeacons are capable of efficiently silencing single gene expression, exogenous siRNA and endogenous miRNAs while yielding a quantifiable fluorescence signal directly proportional to the level of silencing. The silencing potential is comparable to that of traditional siRNA but the same nanoconjugates structure is also capable of reversing the effect of an exogenous siRNA. We further demonstrate the Gold-nanobeacons' efficiency at targeting and silencing miR-21, an endogenous miRNA involved in cancer development, which could become a valid nanotheranostics approach. Again, expression of miR-21 was inhibited with concomitant increase of the Au-nanobeacons' fluorescence that can be used to assess the silencing effect. This way, a single nanostructure can be used to intersect all RNA regulatory pathways while allowing for direct assessment of effective silencing and cell localization via a quantifiable fluorescence signal, making cancer nanotheranostics possible.

The paper aims to understand the degree of transition towards e-mobility. The assumption is that the degree of convergence between actors of each system (batteries, vehicles, grid, policies, business models and consumers) is an indicator of changes in the present socio-technical regime. After an introduction to the socio-technical transition towards e-mobility, the paper presents and discusses three technology assessment approaches to several projects related to technology, society and politics. There are several thematic crossovers between all projects presented leading to a synergetic technology assessment. This output results from the overlapping areas between the cases and can be used to first assess the extent of changes in the present socio-technical regime, as well as to extract standards and regulations, acceptance/risk analyses and behaviour changes that could be significant in the context of a transition towards electric mobility.

The paper aims to understand the degree of transition towards e-mobility. The assumption is that the degree of convergence between actors of each system (batteries, vehicles, grid, policies, business models and consumers) is an indicator of changes in the present socio-technical regime. After an introduction to the socio-technical transition towards e-mobility, the paper presents and discusses three technology assessment approaches to several projects related to technology, society and politics. There are several thematic crossovers between all projects presented leading to a synergetic technology assessment. This output results from the overlapping areas between the cases and can be used to first assess the extent of changes in the present socio-technical regime, as well as to extract standards and regulations, acceptance/risk analyses and behaviour changes that could be significant in the context of a transition towards electric mobility.

Purpose: To assess P-glycoprotein (P-gp)-modulation ability and the mechanisms of P-gp inhibition mediated by a new synthetic rifampicin derivative, 1,8-dibenzoyl-rifampicin (DiBenzRif), in an in vitro model of the blood-brain barrier (BBB), RBE4 cells, and in membrane mimetic models (liposomes). Methods: P-gp expression (western blot) and activity {[}rhodamine 123 accumulation studies] were assessed until 72 h of exposure to DiBenzRif. The effects on intracellular ATP levels and on P-gp ATPase activity were studied using luciferin-luciferase bioluminescence assay. Membrane fluidity changes were tracked by steady-state anisotropy measurements. Non-P-gp-related rhodamine 123 accumulation was evaluated using liposomes prepared with the main lipids present in RBE4 cell membranes. Results: A significant increase in intracellular rhodamine 123 content was observed in DiBenzRif-treated cells at all tested time-points. This effect was associated with a significant reduction in ATP intracellular levels, the inhibition of P-gp ATPase activity and a significant increase in membrane fluidity. DiBenzRif also favoured rhodamine 123 accumulation in a liposomal model of RBE4 cells, suggesting that it may be useful in increasing intracellular levels of substances that passively diffuse into the cells. Conclusion: DiBenzRif-induced inhibitory effect on P-gp increases xenobiotic accumulation in BBB cells, which may contribute to the development of therapeutic adjuvants to enhance brain penetration of drugs. (C) 2013 Elsevier Ireland Ltd. All rights reserved.

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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.

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.