This study aimed to develop edible monolayer emulsion-based barriers with polysaccharides as film-forming components (chitosan and sodium alginate), soy lecithin as a surfactant and olive oil as a ...hydrophobic barrier. Monolayer barriers in the form of films were prepared by casting filmogenic emulsions composed of 2% w/v chitosan (dissolved in lactic acid 1% v/v) or 1% w/v sodium alginate, with different lipid contents (25, 50 and 100% w/w biopolymer basis) and different surfactant concentrations (5, 10 and 25% w/w, lipid basis). Glycerol was used as a plasticizer (25 % w/w, biopolymer basis). After the emulsion drying process, the obtained stand-alone films were sprayed with a crosslinking solution, achieving an optimized crosslinker content of 3.2 mgCa2+/cm2 alginate film and 4 mg tripolyphosphate/cm2 chitosan film. The effect of oil and lecithin contents, as well the presence of crosslinking agents, on the film’s water vapour permeability (WVP), water vapour sorption capacity, mechanical properties and colour parameters, was evaluated. The results have shown that the lowest WVP values were obtained with formulations containing 25% lipid and 25% surfactant for chitosan films, and 100% lipid and 25% surfactant for alginate films. The application of the crosslinking agents decreased even further the WVP, especially for chitosan films (by 30%). Crosslinking also increased films’ resistance to deformation under tensile tests. Overall, the films developed present a good potential as polysaccharide-based barriers with increased resistance to water, which envisages the use of the designed formulations to produce either edible/biodegradable films or edible coatings.
A versatile synthesis of unsaturated seven-membered ring lactams has been developed. The sequence involves hydroamination of Baylis−Hillman acetate with amines, followed by intramolecular ...cyclocarbonylation reactions of the resulting allylamines. This process can tolerate a wide array of functional groups, and affords lactams in excellent yields.
Five hundred Nile tilapia were fed with two diets (with or without microalgae Schizochytrium sp. meal) for different periods (0, 15, 30, 45 and 60 days). The aim of the present study was to ...investigate the effects of the time of supply of Schizochytrium sp microalgae meat in the diet on growth, fatty acid profile and meat quality of Nile tilapia. At growth performance, only the feed consumption and the final weight of the animals varied quadratically, reducing the estimated period to 37 and 38 days respectively. For the characteristics of tilapia fillet meat, only the variable b* (yellowness) showed higher values (2.48) at 30 days of microalgae supply, differing from the control treatment. There was a quadratic effect (p < 0.05) for the total contents of omega‐3 and DHA in the fillet with maximum deposition at 49 days and 52 days respectively. The levels of total omega‐3 fatty acids and DHA in the head, viscera and spine of Nile tilapia increased linearly (p < 0.05) with the increase in the period of offering diets containing Schizochytrium sp. microalgae. Our results suggest that the supply of diets containing Shizochytrium sp microalgae meal for 49 days is enough to increase the omega‐3 content, with massive participation of DHA, in the tilapia fillet without changing other parameters of its quality and zootechnical performance. With this period, the residues obtained from filleting, such as the head, spine and viscera, also benefit from an increase in omega‐3 and DHA.
We propose a real-time vision-based teleoperation approach for robotic arms that employs a single depth-based camera, exempting the user from the need for any wearable devices. By employing a natural ...user interface, this novel approach leverages the conventional fine-tuning control, turning it into a direct body pose capture process. The proposed approach is comprised of two main parts. The first is a nonlinear customizable pose mapping based on Thin-Plate Splines (TPS), to directly transfer human body motion to robotic arm motion in a nonlinear fashion, thus allowing matching dissimilar bodies with different workspace shapes and kinematic constraints. The second is a Deep Neural Network hand-state classifier based on Long-term Recurrent Convolutional Networks (LRCNs) that exploits the temporal coherence of the acquired depth data. We validate, evaluate and compare our approach through both classical cross-validation experiments of the proposed hand state classifier; and user studies over a set of practical experiments involving variants of pick-and-place and manufacturing tasks. Results revealed that LRCNs outperform single image Convolutional Neural Networks; and that users’ learning curves were steep, thus allowing the successful completion of the proposed tasks. When compared to a previous approach, the TPS approach revealed no increase in task complexity and similar times of completion, while providing more precise operation in regions closer to workspace boundaries.
Fresh figs are very appreciated and have been associated with health benefits. However, these fruits are highly perishable. In this study, edible coatings were studied envisaging their positive ...effect in enhancing figs' shelf-life. Fig fruits cv. 'Pingo de mel' were harvested at commercial ripening stage and single emulsion-based coatings, composed of chitosan + olive oil and alginate + olive oil, were applied. After coatings application by dipping each fruit in the emulsion-based solutions at 4 °C and drying, the coated fruits were sprayed with crosslinking solutions (6% tripolyphosphate and 1% calcium chloride for chitosan and alginate-based coatings, respectively). Then, were maintained at 4 °C and analyzed after 1, 7, 14 and 19 days of storage. After each time interval, fruits were further maintained at 25 °C for 2 days. The results have shown that coatings were effective on delaying fungal decay and postharvest ripening indicators (respiration rate, mass loss, softening and total soluble solids/titratable acidity ratio). The results foresee a fruits' shelf life between 14 and 19 days under refrigeration at 4 °C that may be followed up to 2 days at ambient temperature, higher than that estimated for uncoated fruits (less than 14 days at 4 °C plus to 2 days at ambient temperature).
We have developed a novel and efficient three-component one-pot, catalytic approach for the synthesis of 2,3,4,5-tetrahydro-1H-2-benzazepines, using a rhodium catalyst that does not require ...phosphine. The isolated yields are excellent and the protocol tolerates anilines of diverse basicity.
Works addressing the effects of longitudinal magnetic fields in arc welding are still scarce in the literature, and most of them have a theoretical approach. With that in mind, the present work aims ...to investigate, through an experimental approach, the effects of applying an external longitudinal magnetic field on the physical aspects of the arc and the applicability in TIG welding. For that, tests were carried out using welding currents of 50 A and 100 A and magnetic fields of up to 42 mT. As a result, changes in the stagnation pressure profile and arc constriction were verified. With the results, welding tests were performed in order to verify the effects of such changes in the weld bead morphology and microstructure. Showing that penetration could be reduced and the weld bead could be widened by increasing the external magnetic field intensity, yielding a more refined microstructure in the molten zone. Furthermore, the applied magnetic field direction was observed to have an effect on the unilateral displacement of the weld bead.
The main objective of this study was to extend the shelf life of fresh red raspberry (Rubus idaeus. L. cv. ‘Kweli’) by using active film-pads inside commercial compostable packages. The pads were ...produced with chitosan (Ch) with the incorporation of green tea (GTE) and rosemary (RSME) ethanolic extracts as natural antifungal agents. Pads were placed on the bottom of commercial fruit trays underneath the fruits, and the trays were heat-sealed with a polyacid lactic (PLA) film. Preservation studies were carried out over 14 days of storage at refrigeration temperature (4 °C). Raspberry samples were periodically analyzed throughout storage, in terms of quality attributes (fungal decay, weight loss, firmness, surface color, pH, total soluble solids), total phenolic content and antioxidant activity. Gas composition inside the packages was also analyzed over time. From the packaging systems tested, the ones with active film-pads Ch + GTE and Ch + RSME were highly effective in reducing fungal growth and decay of raspberry during storage, showing only around 13% and 5% of spoiled fruits after 14 days, respectively, in contrast with the packages without pads (around 80% of spoiled fruits detected). In addition, fruits preserved using packages with Ch + RSME active film-pads showed lower mass loss (5.6%), decreased firmness (3.7%) and reduced antioxidant activity (around 9% and 15% for DPPH and FRAP methods, respectively). This sustainable packaging presents a potential strategy for the preservation of raspberries and other highly perishable small fruits.
Classifying HEp-2 fluorescence patterns in Indirect Immunofluorescence (IIF) HEp-2 cell imaging is important for the differential diagnosis of autoimmune diseases. The current technique, based on ...human visual inspection, is time-consuming, subjective and dependent on the operator's experience. Automating this process may be a solution to these limitations, making IIF faster and more reliable. This work proposes a classification approach based on Subclass Discriminant Analysis (SDA), a dimensionality reduction technique that provides an effective representation of the cells in the feature space, suitably coping with the high within-class variance typical of HEp-2 cell patterns. In order to generate an adequate characterization of the fluorescence patterns, we investigate the individual and combined contributions of several image attributes, showing that the integration of morphological, global and local textural features is the most suited for this purpose. The proposed approach provides an accuracy of the staining pattern classification of about 90%.
•We propose a HEp-2 classification strategy based on Subclass Discriminant Analysis.•Our approach copes well with the high within-class variance of HEp-2 patterns.•We investigate the individual and combined contribution of different image attributes.•We integrate morphological, global and local textural information.•Our approach provides staining pattern classification accuracy of about 90%.
Tandem palladium-catalyzed N,C-coupling/carbonylation, under 10 atm of carbon monoxide and at 110 °C, is a novel and efficient method for the preparation of 2-carboxyindoles. The catalyst system ...tolerates a variety of functional groups, and the noted indoles were obtained in good isolated yields.
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