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.

In this work, a combination of homology modeling and molecular dynamics (MD) simulations was used to investigate the factors that modulate substrate specificity and activity of the mouse AOX isoforms: mAOX1, mAOX2 (previously mAOX3l1), mAOX3 and mAOX4. The results indicate that the AOX isoform structures are highly preserved and even more conserved than the corresponding amino acid sequences. The only differences are at the protein surface and substrate-binding site region. The substrate-binding site of all isoforms consists of two regions: the active site, which is highly conserved among all isoforms, and a isoform-specific region located above. We predict that mAOX1 accepts a broader range of substrates of different shape, size and nature relative to the other isoforms. In contrast, mAOX4 appears to accept a more restricted range of substrates. Its narrow and hydrophobic binding site indicates that it only accepts small hydrophobic substrates. Although mAOX2 and mAOX3 are very similar to each other, we propose the following pairs of overlapping substrate specificities: mAOX2/mAOX4 and mAOX3/mAXO1. Based on these considerations, we propose that the catalytic activity between all isoforms should be similar but the differences observed in the binding site might influence the substrate specificity of each enzyme. These results also suggest that the presence of several AOX isoforms in mouse allows them to oxidize more efficiently a wider range of substrates. This contrasts with the same or other organisms that only express one isoform and are less efficient or incapable of oxidizing the same type of substrates.

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.

Since long ago cellulosic lyotropic liquid crystals were thought as potential materials to produce fibers competitive with spidersilk or Kevlar, yet the processing of high modulus materials from cellulose-based precursors was hampered by their complex rheological behavior. In this work, by using the Rheo-NMR technique, which combines deuterium NMR with rheology, we investigate the high shear rate regimes that may be of interest to the industrial processing of these materials. Whereas the low shear rate regimes were already investigated by this technique in different works [1-4], the high shear rates range is still lacking a detailed study. This work focuses on the orientational order in the system both under shear and subsequent relaxation process arising after shear cessation through the analysis of deuterium spectra from the deuterated solvent water. At the analyzed shear rates the cholesteric order is suppressed and a flow-aligned nematic is observed which for the higher shear rates develops after certain time periodic perturbations that transiently annihilate the order in the system. During relaxation the flow aligned nematic starts losing order due to the onset of the cholesteric helices leading to a period of very low order where cholesteric helices with different orientations are forming from the aligned nematic, followed in the final stage by an increase in order at long relaxation times corresponding to the development of aligned cholesteric domains. This study sheds light on the complex rheological behavior of chiral nematic cellulose-based systems and opens ways to improve its processing. (C) 2015 Elsevier Ltd. All rights reserved.

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.

Glucans are polymers of D-glucose with differing linkages in linear or branched sequences. They are constituents of microbial and plant cell-walls and involved in important bio-recognition processes including immunomodulation, anti-cancer activities, pathogen virulence and plant cell-wall biodegradation. Translational possibilities for these activities in medicine and biotechnology are considerable. High-throughput micro-methods are needed to screen proteins for recognition of specific glucan sequences as a lead to structure-function studies and their exploitation. We describe construction of a glucome microarray, the first sequence-defined glycome-scale microarray, using a designer approach from targeted ligand-bearing glucans in conjunction with a novel high-sensitivity mass spectrometric sequencing method, as a screening tool to assign glucan recognition motifs. The glucome microarray comprises 153 oligosaccharide probes with high purity, representing major sequences in glucans. The negative-ion electrospray tandem mass spectrometry with collision-induced dissociation was used for complete linkage analysis of gluco-oligosaccharides in linear homo and hetero and branched sequences. The system is validated using antibodies and carbohydrate-binding modules known to target α- or β-glucans in different biological contexts, extending knowledge on their specificities, and applied to reveal new information on glucan recognition by two signalling molecules of the immune system against pathogens: Dectin-1 and DC-SIGN. The sequencing of the glucan oligosaccharides by the MS method and their interrogation on the microarrays provides detailed information on linkage, sequence and chain length requirements of glucan-recognizing proteins, and are a sensitive means of revealing unsuspected sequences in the polysaccharides.

Fucopol, a fucose-containing exopolysaccharide (EPS) produced by the bacterium Enterobacter A47 DSM 23139 using glycerol as a carbon source, was employed as a new coating material for iron oxide magnetic nanoparticles (MNPs). The coated particles were assessed as nanoprobes for cell labeling by Magnetic Resonance Imaging (MRI). The MNPs were synthesized by a thermal decomposition method and transferred to an aqueous medium by a ligand-exchange reaction with meso-2,3-dimercaptosuccinic acid (DMSA). Covalent binding of EPS to DMSA-stabilized nanoparticles (MNP-DMSA) resulted in a hybrid magnetic-biopolymeric nanosystem (MNP-DMSA-EPS) with a hydrodynamic size of 170 nm, a negative surface charge under physiological conditions and transverse to longitudinal relaxivity ratio, r2/r1, of 148. In vitro studies with two human cell lines (colorectal carcinoma - HCT116 - and neural stem/progenitor cells - ReNcell VM) showed that EPS promotes internalization of nanoparticles in both cell lines. In vitro MRI cell phantoms showed a superior performance of MNP-DMSA-EPS in ReNcell VM, for which the iron dose-dependent MRI signal drop was obtained at relatively low iron concentrations (12-20 mug Fe per ml) and short incubation times. Furthermore, ReNcell VM multipotency was not affected by culture in the presence of MNP-DMSA or MNP-DMSA-EPS for 14 days. Our study suggests that Fucopol-coated MNPs represent useful cell labeling nanoprobes for MRI.

Aluminum Zinc Oxide has been extensively investigated as a cheap alternative to transparent conducting tin oxide films for electronic and optoelectronic applications. Thin films of Aluminum Zinc Oxide have been developed successfully through a combination of solution combustion synthesis and solution synthesis. Zn(NO3)3·6H2O as metal source was dissolved in 2-methoxyethanol as solvent through combustion synthesis with Urea as fuel while dopant source of AlCl3·6H2O was mixed separately in solvent to avoid aluminum oxide formation in the films. Precursor solutions were obtained mixing Zn {&} Al separate solutions in 9:1, 8:2, and 7:3 ratios respectively with oxide, fuel and dopant concentrations of 0.5, 0.25, 0.1, and 0.05 M. The film stacks have been prepared through spin-coating with heating at 400°C for 10 minutes after each deposition to remove residuals and evaporate solvents. Thermal annealing in oven at 600°C for 1 hour followed by rapid thermal annealing at 500°C {&} 600°C first in vacuum and then in N2-5{%}H2 environment respectively for 10 minutes each reduced the resistivity of film stacks. Film stack with 10 layers for an average thickness of 0.5$μ$m gave the best Hall Effect resistivity of 3.2 × 10-2 $Ømega$-cm in the case of 0.5M solution with Zn:Al mixing ratio of 9:1 for RTA annealings at 600°C with an average total transparency of 80 {%} in the wavelength range of 400-1200 nm. The results show a clear trend that increasing the amount of ingredients resistivity could further be decreased.

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.

Identification of specific nucleic acid sequences mediated by gold nanoparticles derivatized thiol-modified oligonucleotides (Au-nanoprobes) has been proven to be a useful tool in molecular diagnostics. Here, we demonstrate that, on optimization, detection may be simplified via the use of a single Au-nanoprobe to detect a single nucleotide polymorphism (SNP) in homo- or heterozygote condition. We validated this non-cross-linking approach through the analysis of 20 clinical samples using a single specific Au-nanoprobe for an SNP in the FTO (fat mass and obesity-associated) gene against direct DNA sequencing. Sensitivity, specificity, and limit of detection CLOD) were determined, and statistical differences were calculated by one-way analysis of variance (ANOVA) and a post hoc Tukey's test to ascertain whether there were any differences between Au-nanoprobe genotyped groups. For the first time, we show that the use of a single Au-nanoprobe can detect SNP for each genetic status (wild type, heterozygous, or mutant) with high degrees of sensitivity (87.50%) and specificity (91.67%). (c) 2014 Elsevier Inc. All rights reserved.

There is a strong interest in the use of biopolymers in the electronic and biomedical industries, mainly towards low-cost applications. The possibility of developing entirely new kinds of products based on cellulose is of current interest, in order to enhance and to add new functionalities to conventional paper-based products. We present our results towards the development of paper-based microfluidics for molecular diagnostic testing. Paper properties were evaluated and compared to nitrocellulose, the most commonly used material in lateral flow and other rapid tests. Focusing on the use of paper as a substrate for microfluidic applications, through an eco-friendly wax-printing technology, we present three main and distinct colorimetric approaches: (i) enzymatic reactions (glucose detection); (ii) immunoassays (antibodies anti-Leishmania detection); (iii) nucleic acid sequence identification (Mycobacterium tuberculosis complex detection). Colorimetric glucose quantification was achieved through enzymatic reactions performed within specific zones of the paper-based device. The colouration achieved increased with growing glucose concentration and was highly homogeneous, covering all the surface of the paper reaction zones in a 3D sensor format. These devices showed a major advantage when compared to the 2D lateral flow glucose sensors, where some carryover of the coloured products usually occurs. The detection of anti-Leishmania antibodies in canine sera was conceptually achieved using a paper-based 96-well enzyme-linked immunosorbent assay format. However, optimization is still needed for this test, regarding the efficiency of the immobilization of antigens on the cellulose fibres. The detection of Mycobacterium tuberculosis nucleic acids integrated with a non-cross-linking gold nanoprobe detection scheme was also achieved in a wax-printed 384-well paper-based microplate, by the hybridization with a species-specific probe. The obtained results with the above-mentioned proof-of-concept sensors are thus promising towards the future development of simple and cost-effective paper-based diagnostic devices.