Effect of air-drying temperature on physico-chemical properties of dietary fibre and antioxidant capacity of orange (Citrus aurantium v. Canoneta) by-products

Dehydration promoted important modifications affecting both the physico-chemical properties of dietary fibre (DF) and the antioxidant capacity of orange by-products (peel and pulp remaining after juice extraction). The significance of such changes was largely dependent on the air-drying temperature used (from 30 °C to 90 °C). The major modifications on the DF components were observed when either extended drying periods, i.e. at lower temperatures, or elevated drying temperatures were applied. Dehydration around 50–60 °C apparently promoted the minor disruption of cell wall polymers, in particular of pectic substances. Pulp samples exhibited higher values of swelling (SW) and fat adsorption capacity (FAC) than those derived from orange peel. Although, significant decreases in water retention capacity (WRC), FAC and solubility values were detected for both by-products as the air-drying temperature increased. The antioxidant capacity associated to dehydrated citrus by-products was significantly higher for orange peel than for pulp samples. In general, the by-products studied proved to be quite resistant to the different heat treatments applied within the range of 40–70 °C. In overall, the study shows that, in order to preserve either the DF quality and/or the antioxidant capacity, air-drying temperature should be controlled since both types of compounds, DF components and antioxidants, might be degraded or modified either when extended drying periods and/or high drying temperatures are applied.     

Influence of storage period and packaging method on sliced dry cured beef "Cecina de Leon": Effects on microbiological, physicochemical and sensory quality

Quality aspects of sliced dry-cured beef “Cecina de León” preserved in vacuum and gas mixtures (20%/80% CO₂/N₂ and 80%/20% CO₂/N₂) were studied. The evolution of microbiological, physicochemical and sensory parameters were analysed during storage (210 days) at 6 °C. Although microbial counts at 60 days of the gas-packaged samples were lower than the vacuum-packed ones, they were never higher than the spoilage limit (7 log ufc/g). A slight increase (p < 0.05) in pH was observed throughout storage of “Cecina de León” packaged under vacuum and in gas mixtures. However, a decrease (p < 0.05) in a_w was observed during storage of “Cecina de León” packaged under vacuum but a_w did not vary (p > 0.05) during storage in the gas-packaged samples. No changes were observed (p > 0.05) in lightness (L^*), redness (a^*) and yellowness (b^*) in vacuum and gas packaged samples during storage. However, sensorially evaluated colour showed lower values in gas packaged samples during 30 days storage. This difference was decisive in establishing the shelf-life of “Cecina de León” slices preserved in gas mixtures (20%/80% CO₂/N₂ and 80%/20% CO₂/N₂). Therefore, from a microbiological point of view, gas mixtures are more effective in extending the shelf-life of “Cecina de León” slices. It is concluded that vacuum packaging allows longer storage than gas-packaging as it maintains a good visual appearance of “Cecina de León”, the main parameter in consumers’ perception of meat quality.     

Behaviour of non-stressed and stressed Listeria monocytogenes and Campylobacter jejuni cells on fresh chicken burger meat packaged under modified atmosphere and inoculated with protective culture

Numerous investigations have provided evidence that chicken products are a source of Listeria monocytogenes and Campylobacter jejuni. Different strategies applied in final products are needed to prevent consumers' contamination. In this work, the combination of modified atmosphere packaging (MAP) and protective culture to control the growth of freeze stressed and non-stressed L. monocytogenes and C. jejuni on fresh chicken meat burger was studied. Meat burgers were inoculated with L. monocytogenes, C. jejuni and Leuconostoc pseudomesenteroides PCK 18, as protective strain against L. monocytogenes. Prior to the addition of the protective culture, half of the L. monocytogenes and C. jejuni - inoculated meat was frozen at -18°C for 48h to subject cells to stress. Following the addition of the protective culture, meat burgers were packaged in air or MAP (50% CO(2)/50% O(2)) and stored under refrigeration conditions. L. monocytogenes counts were not reduced by the freezing temperature applied; however, the addition of Lc. pseudomesenteroides PCK 18 reduced its counts for 0.90 log cfu/g when chicken meat burgers were packaged under MAP. Furthermore, freezing stress was an effective strategy to reduce C. jejuni counts but only in combination with a high-O(2) MAP, it was completely eliminated. Chicken meat burgers' shelf-life under aerobic packaging conditions was reduced by the effect of freeze-thawing, while the use of MAP extended the product's shelf-life till 21days. Therefore, the combination of freezing, protective culture and MAP could extend the shelf-life and enhance the food safety of this kind of chicken products.     

Effects of smoking bans on passive smoking exposure at work and at home. The European Community respiratory health survey

This longitudinal study investigated whether smoking bans influence passive smoking at work and/or at home in the same subjects. Passive smoking at work and/or at home was investigated in random population samples (European Community Respiratory Health Survey) in 1990‐1995, with follow‐up interviews in 1998‐2003 and 2010‐2014. National smoking bans were classified as partial (restricted to public workplaces) or global (extended to private workplaces). Multivariable analysis was accomplished by three‐level logistic regression models, where level‐1, level‐2, and level‐3 units were, respectively, questionnaire responses, subjects, and centers. Passive smoking at work was reported by 31.9% in 1990‐1995, 17.5% in 1998‐2003, and 2.5% in 2010‐2014. Concurrently, passive smoking at home decreased from 28.9% to 18.2% and 8.8%. When controlling for sex, age, education, smoking status, and ECHRS wave, the odds of passive smoking at work was markedly reduced after global smoking bans (OR = 0.45, 95% CI 0.25‐0.81), particularly among non‐smokers, while the protective effect of global smoking bans on passive smoking at home was only detected in non‐smokers. Smoking bans both in public and private workplaces were effective in reducing passive smoking at work in Europe. However, given the inefficacy of smoking bans in current smokers’ dwellings, better strategies are needed to avoid smoking indoors.     

Synthesis and Characterization of an Fe/Co Ferrite Spinel Oxide Film Produced by Using N2/Steam Heat Treatment on Two Maraging Steels

An experimental procedure was developed to obtain an oxide layer formed mainly by spinel on maraging steels. It consists of different stages with specific conditions, such as atmospheres rich in nitrogen and water vapor, and different steps of temperatures and times. Tests were performed on grade 300 and 350 maraging steels. Oxide layer characterization was done using optical and electron microscopy, spectroscopy, X-ray diffraction, and nanoscratch tests in order to determine the adhesion force as well as to observe the main deformation mechanism induced under sliding tests. In both steels, oxide layers are formed by the spinel’s Fe₃O₄ and CoFe₂O₄ in amounts close to ca. 85 pct, whereas TiO₂ and MoO₃ represent the other 15 pct. No hematite was found. The low oxygen availability during the heat treatment was fundamental for avoiding hematite formation. A nickel-rich austenitic phase formed at the metal-oxide interface due the kinetics of the oxidation process of the cobalt, iron, and molybdenum. The particular conditions of the heat treatments induced the formation of a mixture of iron, nickel, and cobalt spinel ferrites, thereby contradicting previous studies that said that only magnetite would be formed. The sliding tests at the nanometric length scale highlight that the layer formed on maraging 300 grade presents a better adhesion than the other investigated material due to the fact that it requires more load in order to induce cracks located at the edge of the sliding track and, subsequently, the chipping of the formed layer.

Graphical abstract

     

Acceleration‐Based Automated Vehicle Classification on Mobile Bridges

Mobile bridges have been used for a broad range of applications including military transportation or disaster restoration. Because mobile bridges are rapidly deployed under a wide variety of conditions, often remaining in place for just minutes to hours, and have irregular usage patterns, a detailed record of usage history is important for ensuring structural safety. To facilitate usage data collection in mobile bridges, a new acceleration‐based vehicle classification technique is proposed to automatically identify the class of each vehicle. Herein we present a new technique that is based on the premise that each class of vehicles produces distinctive dynamic patterns while crossing this mobile bridge, and those patterns can be extracted from the system's acceleration responses. Measured acceleration signals are converted to time–frequency images to extract two‐dimensional patterns. The Viola–Jones object detection algorithm is applied here to extract and classify those patterns. The effectiveness of the technique is investigated and demonstrated using laboratory and full‐scale mobile bridges by simulating realistic scenarios.     

Ozone/H2O2 Performance on the Degradation of Sulfamethoxazole

This work aims to analyze the contribution of H₂O₂ on ozonation of Sulfamethoxazole (SMX). A single ozonation was able to totally remove SMX. TOC and COD depletion rates after a transferred ozone dose of 60 mg/L was related to the formation and decomposition of H₂O₂. An increase on O₃ gas inlet concentration from 10 g/m³ to 20 g/m³ improved COD abatement from 11% to 36%. When the presence of H₂O₂ at the beginning of ozonation was tested, it was verified that COD and TOC degradation were enhanced, attaining maximum values of 76% and 32%, respectively, when compared with 35% and 15% reached in a single ozonation.     

Fusing Visual and Inertial Sensing to Recover Robot Ego‐motion

A method for estimating mobile robot ego‐motion is presented, which relies on tracking contours in real‐time images acquired with a calibrated monocular video system. After fitting an active contour to an object in the image, 3D motion is derived from the affine deformations suffered by the contour in an image sequence. More than one object can be tracked at the same time, yielding some different pose estimations. Then, improvements in pose determination are achieved by fusing all these different estimations. Inertial information is used to obtain better estimates, as it introduces in the tracking algorithm a measure of the real velocity. Inertial information is also used to eliminate some ambiguities arising from the use of a monocular image sequence. As the algorithms developed are intended to be used in real‐time control systems, considerations on computation costs are taken into account. © 2004 Wiley Periodicals, Inc.     

Control and simulation of a tensegrity-based mobile robot

Tensegrity structures can provide a new approach to the construction of mobile robots with different shapes and properties that usual robots, wheeled or legged, do not have. Tensegrity are light, deformable structures that may be able to adapt their form to unconstrained environments. The main issue of this paper is twofold, first, to derive appropriate and general dynamic equations of motion to study the movement of such structures in the space; second to demonstrate, by means of simulation, that a tensegrity structure can execute any desired trajectory path by actuating some or all of its elements.     

A nanoporous molecular magnet with reversible solvent-induced mechanical and magnetic properties

Interest in metal-organic open-framework structures has increased enormously in the past few years because of the potential benefits of using crystal engineering techniques to yield nanoporous materials with predictable structures and interesting properties. Here we report a new efficient methodology for the preparation of metal-organic open-framework magnetic structures based on the use of a persistent organic free radical (PTMTC), functionalized with three carboxylic groups. Using this approach, we create an open-framework structure Cu3(PTMTC)2(py)6(CH3CH2OH)2(H2O), which we call MOROF-1, combining very large pores (2.8-3.1 nm) with bulk magnetic ordering. MOROF-1 shows a reversible and highly selective solvent-induced 'shrinking-breathing' process involving large volume changes (25-35%) that strongly influence the magnetic properties of the material. This magnetic sponge-like behaviour could be the first stage of a new route towards magnetic solvent sensors.