Three iron(III) complexes with ligands derived from N-ethyl-N-(2-aminoethyl) salicylaldiminate (H, 1; 5-Br, 2; 3-OMe, 3 substituents at the phenyl group) were prepared and the X-ray crystal structures of 1 and 2 are reported. NMR studies of solutions of these complexes in DMSO allowed for investigation of their magnetic behaviour and paramagnetic relaxation contribution. The relaxivities measured ranged from 0.35 to 0.80 mM(-1) s(-1) for proton Larmor frequencies from 0.01 to 300 MHz, in agreement with those known for other iron(III) based contrast agents. Biological studies on colonic epithelial T-84 cell monolayers showed that the compounds exert toxic effects only at concentrations higher than 100 mu M while coincidently reducing colonic epithelial secretory function. These two features make these complexes good candidates for further development in order to be used as MRI contrast agents. (C) 2015 Elsevier B.V. All rights reserved.

Molecular mobility is a fundamental parameter which reflects the dynamic properties of food components and contributes to food degradation reactions comprehension. Fresh-cut fruits have become an important food market segment. However, processing of fruits promotes faster its physiological deterioration, biochemical changes and microbial degradation. The purpose of this work was to use NMR methodology as a tool to evaluate fresh-cut fruit quality, during storage at refrigerated conditions. The fresh-cut melon transverse relaxation time (T-2) was measured for a period of 7 days of storage at 5 degrees C. The relationship between the obtained values, microstructure and quality parameters was investigated. In general, results show the existence of one class of water fluidity in the system, the one present in cells after processing. T-2, a measure of this fluidity, is affected by the processing and storage time. Also, it is possible to find a close relationships between T-2 and quality parameters of total colour difference (TCD), firmness and a(w). As T-2 increases TCD also increases, while firmness and aw decrease. These results highlight the usefulness of NMR methodology application in food science. (C) 2015 Elsevier Ltd. All rights reserved.

The biomass yield potential of Mastocarpus stellatus, a commercially attractive carrageenophyte for foods and pharmaceutics, was investigated by cultivating the seaweeds in the nutrient-rich outflow of a commercial fish farm. Results from two consecutive 4 weeks experiments indicate that the cultivation of this seaweed produces a mean biomass of 21 to 40.6 gDW m(-2) day(-1) depending on the time of the experiment. DRIFT and CP-MAS NMR analyses of seaweeds indicate that cultivation during May affected quantitatively the seaweeds chemistry, and thus the chemical and gelling properties of native extracts of kappa/iota-hybrid carrageenan (KI). Overall, algal growth leads to the production of more sulphated KI, the percentage increase varying between 27% and 44% for the two experiments. However, alkali treatment of seaweeds before extraction reduces the variations in gelling properties of KI induced by the algal growth. This study demonstrates the capacity of growing M. stellatus in an integrated multi-trophic aquaculture system for the sustainable production of high value polysaccharides.

Abstract Humic substances (HS) constitute a significant fraction of natural organic matter in terrestrial and aquatic environments and can act as terminal electron acceptors in anaerobic microbial respiration. Geobacter sulfurreducens has a remarkable respiratory versatility and can utilize the \{HS\} analog anthraquinone-2,6-disulfonate (AQDS) as a terminal electron acceptor or its reduced form (AH2QDS) as an electron donor. Previous studies set the triheme cytochrome PpcA as a key component for \{HS\} respiration in G. sulfurreducens, but the process is far from fully understood. In this work, \{NMR\} chemical shift perturbation measurements were used to map the interaction region between PpcA and AH2QDS, and to measure their binding affinity. The results showed that the \{AH2QDS\} binds reversibly to the more solvent exposed edge of PpcA heme IV. The \{NMR\} and visible spectroscopies coupled to redox measurements were used to determine the thermodynamic parameters of the PpcA:quinol complex. The higher reduction potential of heme İV\} (− 127 mV) compared to that of \{AH2QDS\} (− 184 mV) explains why the electron transfer is more favorable in the case of reduction of the cytochrome by the quinol. The clear evidence obtained for the formation of an electron transfer complex between \{AH2QDS\} and PpcA, combined with the fact that the protein also formed a redox complex with AQDS, revealed for the first time the bifunctional behavior of PpcA toward an analog of the HS. Such behavior might confer selective advantage to G. sulfurreducens, which can utilize the \{HS\} in any redox state available in the environment for its metabolic needs.

BACKGROUND The emergence of monoclonal antibodies (mAbs) as new biopharmaceutical products requires the development of new purification methods that are not only effective but are able to reduce production costs. To address the problematic recovery of mAbs, gum arabic (GA) coated magnetic particles (MPs) were used for the purification of human antibodies from animal cells supernatants. RESULTS MPs were synthesized via co-precipitation and exhibited a spherical-like physical aspect, with an average hydrodynamic diameter of 473 nm and a zeta potential of –26 mV. The adsorption and elution of IgG on these adsorbents was thoroughly studied. Adsorption of human IgG was enhanced at pH 6, for which a qmax of 244 mg IgG g−1 MPs and Kd of 25 mg L−1 were obtained. Increasing salt concentrations at a basic pH (1 mol L−1 NaCl at pH 11) were found to improve the elution of bound IgG. The MPs were challenged with an artificial protein mixture containing human IgG, albumin, insulin and apo-transferrin. An overall yield of 84% was achieved, retrieving 92% of bound IgG. CONCLUSIONS MPs were successfully used for the capture of monoclonal antibodies from two distinct mammalian cell cultures, a Chinese hamster ovary (CHO) and a hybridoma cell culture supernatants. The elution yields were high, ranging between 84% and 94%, with overall yields ranging from 72% to 88%. Final purities of 85% were reached for hybridoma cell supernatants. © 2014 Society of Chemical Industry

Branching at the alkyl side chain of the imidazolium cation in ionic liquids (ILs) was evaluated towards its effect on carbon dioxide (CO2 ) solubilization at 10 and 80 bar (1 bar=1x10(5) Pa). By combining high-pressure NMR spectroscopy measurements with molecular dynamics simulations, a full description of the molecular interactions that take place in the IL-CO2 mixtures can be obtained. The introduction of a methyl group has a significant effect on CO2 solubility in comparison with linear or fluorinated analogues. The differences in CO2 solubility arise from differences in liquid organization caused by structural changes in the cation. ILs with branched cations have similar short-range cation-anion orientations as those in ILs with linear side chains, but present differences in the long-range order. The introduction of CO2 does not cause perturbations in the former and benefits from the differences in the latter. Branching at the cation results in sponge-like ILs with enhanced capabilities for CO2 capture.

Multiheme cytochromes have been implicated in Geobacter sulfurreducens (Gs) extracellular electron transfer (EET). These proteins are potential targets to improve EET and enhance bioremediation and electrical current production by Gs. However, the functional characterization of multiheme cytochromes is particularly complex due to the co-existence of several microstates in solution, connecting the fully reduced and fully oxidized states. Over the last decade, new strategies have been developed to characterize multiheme redox proteins functionally and structurally. These strategies were used to reveal the functional mechanism of Gs multiheme cytochromes and also to identify key residues in these proteins for EET. In previous studies, we set the foundations for enhancement of the EET abilities of Gs by characterizing a family of five triheme cytochromes (PpcA-E). These periplasmic cytochromes are implicated in electron transfer between the oxidative reactions of metabolism in the cytoplasm and the reduction of extracellular terminal electron acceptors at the cell’s outer surface. The results obtained suggested that PpcA can couple e-/H+ transfer, a property that might contribute to the proton electrochemical gradient across the cytoplasmic membrane for metabolic energy production. The structural and functional properties of PpcA were characterized in detail and used for rational design of a family of 23 single site PpcA mutants. In this review, we summarize the functional characterization of the native and mutant proteins. Mutants that retain the mechanistic features of PpcA and adopt preferential e-/H+ transfer pathways at lower reduction potential values compared to the wild-type protein were selected for in vivo studies as the best candidates to increase the electron transfer rate of Gs. For the first time Gs strains have been manipulated by the introduction of mutant forms of essential proteins with the aim to develop and improve bioelectrochemical technologies.

Foods are partially crystalline partially amorphous systems. Edible films are considered good models for food systems due to their interesting physical properties, quite straightforward matrices, and easy reproduction. Chitosan is a semicrystalline biopolymer, biocompatible, biodegradable, with antimicrobial activity and filmogenic properties, thoroughly used in edible films' studies. This work aims to investigate the relationship between chitosan films' molecular relaxation time, their microstructure (crystallinity) and functional properties. Analyses were carried out using data on chitosan/glycerol films prepared with different polymer/plasticisant concentrations. Results demonstrate that there is a relationship between macroscopic properties and water and glycerol relaxation times. Moreover, results show that while water is free in the matrix, glycerol is linked to the chitosan polymeric chains, decreasing intermolecular attractions and increasing free volume, thus facilitating molecular migration. Also the data analysis reveals the usefulness of NMR and molecular mobility studies in the matrix for characterisation and development of polymeric structures. Industrial relevance: NMR spectroscopy is currently one of the key methods for food characterisation. Foodstuff is a complex matrix including many different compounds with different chemical structures, concentrations, solubility, properties and nutritional values. From a fundamental perspective, foods are mainly edible and digestible biopolymers that are partially crystalline/partially amorphous and thus edible films, specifically chitosan/glycerol films can be very interesting food model systems for mobility and microstructure studies. Studies on water and solids' mobility and thermo-mechanical properties in food systems (real or model systems),are fundamental to fully attain food physical properties and stability. These studies may be extremely useful for food product and process design, safety and sensorial attributes and also for better understanding and predicting, for example, food storage stability conditions. (C) 2015 Elsevier Ltd. All rights reserved.

Gold glyconanoparticles (GlycoNPs) are full of promise in areas like biomedicine, biotechnology and materials science due to their amazing physical, chemical and biological properties. Here, siRNA GlycoNPs (AuNP@PEG@Glucose@siRNA) in comparison with PEGylated GlycoNPs (AuNP@PEG@Glucose) were applied in vitro to a luciferase-CMT/167 adenocarcinoma cancer cell line and in vivo via intratracheal instillation directly into the lungs of B6 albino mice grafted with luciferase-CMT/167 adenocarcinoma cells. siRNA GlycoNPs but not PEGylated GlycoNPs induced the expression of pro-apoptotic proteins such as Fas/CD95 and caspases 3 and 9 in CMT/167 adenocarcinoma cells in a dose dependent manner, independent of the inflammatory response, evaluated by bronchoalveolar lavage cell counting. Moreover, in vivo pulmonary delivered siRNA GlycoNPs were capable of targeting c-Myc gene expression (a crucial regulator of cell proliferation and apoptosis) via in vivo RNAi in tumour tissue, leading to an similar to 80% reduction in tumour size without associated inflammation.

Four silica-based porous nanosystems were synthesized with different organic substitutes and the molecular dynamics of water in these constrained environment was investigated. The nanosystems were silica and three organic modified silica nanoparticles (NP) with diameters in the range 80-300 nm with different porous dimensions, surface areas, and surface properties (e.g. hydrophilicity/hydrophobicity). Molecular dynamics was studied by pulsed field gradient NMR and by proton spin-lattice relaxation in a broad range of Larmor frequencies. A coherent analysis of the diffusion coefficients and spin-lattice relaxation data is presented taking into account a relaxation model associated to water molecular dynamics in close contact with NP surfaces. From our results it was possible to access the details of the water molecular movements in the nanosystems and to single out two water populations presenting distinct molecular dynamics. Characteristic distances for water rotations mediated by translational diffusion were estimated in consistency with the NP's dimensions and pores sizes obtained by TEM and BET experimental techniques. This knowledge has both fundamental and practical relevance since these NP have applications in nanomedicine, not only in therapy but also in diagnostic procedures and more recently in theranostic. (C) 2015 Elsevier Inc. All rights reserved.

We study the polarization characteristics of X-ray photons scattered by hydrogenic atoms, based on the Dirac equation and second-order perturbation theory. The.

Abstract The monoheme c-type cytochrome PccH from Geobacter sulfurreducens, involved in the pathway of current-consumption in biofilms, was electrochemically characterized in detail. Cyclic voltammetry was used to determine the kinetics and thermodynamics properties of PccH redox behavior. Entropy, enthalpy and Gibbs free energy changes associated with the redox center transition between the ferric and the ferrous state were determined, indicating an enhanced solvent exposure. The midpoint redox potential is considerably low for a monoheme c-type cytochrome and the heterogeneous electron transfer constant rate reflects a high efficiency of electron transfer process in PccH. The midpoint redox potential dependence on the pH (redox-Bohr effect) was investigated, over the range of 2.5 to 9.1, and is described by the protonation/deprotonation events of two distinct centers in the vicinity of the heme group with pKa values of 2.7 (pKox1); 4.1 (pKred1) and 5.9 (pKox2); 6.4 (pKred2). Based on the inspection of PccH structure, these centers were assigned to heme propionic acids \{P13\} and P17, respectively. The observed redox-Bohr effect indicates that PccH is able to thermodynamically couple electron and proton transfer in the G. sulfurreducens physiological pH range.

This paper focuses on the engineering procedures governing the synthesis of tungsten oxide nanocrystals and the formulation of printable dispersions for electrochromic applications. By that means, we aim to stress the relevancy of a proper design strategy that results in improved physicochemical properties of nanoparticle loaded inks. In the present study inkjet printable nanostructured tungsten oxide particles were successfully synthesized via hydrothermal processes using pure or acidified aqueous sol-gel precursors. Based on the proposed scheme, the structure and morphology of the nanoparticles were tailored to ensure the desired printability and electrochromic performance. The developed nanomaterials with specified structures effectively improved the electrochemical response of printed films, resulting in 2.5 times higher optical modulation and 2 times faster coloration time when compared with pure amorphous films.