Physiochemical Changes of Starch During Maize Tortilla Production

The physiochemical changes of starch in maize tortillas and their intermediate products commercially processed by the traditional way have been determined. Samples of maize, nixtamal, dough or masa, tortilla and nejayote (steep liquor) were analyzed. The samples were assayed for water absorption index (WAI), resistant starch (RS), X-ray diffraction patterns, viscosity and with Differential Scanning Calorimetry (DSC). Enthalpy of fusion (ΔH), initial temperature (T_o) and transition temperature (T_p) of gelatinization were obtained from DSC curves. Resistant starch contents increased as the products advanced in the process. Significant differences (p > 0.05) in the fusion enthalpy values of maize, nixtamal and masa could not be found. X-ray diffraction patterns of maize, nixtamal and masa did not show significant changes; however, when masa was transformed into tortillas there was a large loss in crystallinity. The viscoamylograph peak viscosities increased from maize to masa and decreased drastically in tortillas. The data showed that the tortilla baking stage caused the most pronounced changes in starch.     

Potential Anti-Metastatic Role of the Novel miR-CT3 in Tumor Angiogenesis and Osteosarcoma Invasion

Osteosarcoma (OS) is the most common primary bone tumor mainly occurring in young adults and derived from primitive bone-forming mesenchyme. OS develops in an intricate tumor microenvironment (TME) where cellular function regulated by microRNAs (miRNAs) may affect communication between OS cells and the surrounding TME. Therefore, miRNAs are considered potential therapeutic targets in cancer and one of the goals of research is to accurately define a specific signature of a miRNAs, which could reflect the phenotype of a particular tumor, such as OS. Through NGS approach, we previously found a specific molecular profile of miRNAs in OS and discovered 8 novel miRNAs. Among these, we deepen our knowledge on the fifth candidate renamed now miR-CT3. MiR-CT3 expression was low in OS cells when compared with human primary osteoblasts and healthy bone. Through TargetScan, VEGF-A was predicted as a potential biological target of miR-CT3 and luciferase assay confirmed it. We showed that enforced expression of miR-CT3 in two OS cell lines, SAOS-2 and MG-63, reduced expression of VEGF-A mRNA and protein, inhibiting tumor angiogenesis. Enforced expression of miR-CT3 also reduced OS cell migration and invasion as confirmed by soft agar colony formation assay. Interestingly, we found that miR-CT3 behaves inducing the activation of p38 MAP kinase pathway and modulating the epithelial-mesenchymal transition (EMT) proteins, in particular reducing Vimentin expression. Overall, our study highlights the novel role of miR-CT3 in regulating tumor angiogenesis and progression in OS cells, linking also to the modulation of EMT proteins.     

Effect of processing additives on (bio)degradability of film-blown poly(ε-caprolactone)

Poly(ε-caprolactone)s (PCL) with slip masterbatch, Erucamide, SiO₂ and Erucamide + CaCO₃ as low-molecular-weight processing additives, were film-blown in a single screw extruder. The films and recycled PCL without additives were exposed to composting, anaerobic sewage sludge (37 and 55°C), pure fungal culture, and chemical hydrolysis at two pH (7 and 10.5) and at two temperatures (room temperature and 50°C). Recycling and addition of processing additives resulted in a slightly slower degradation rate compared with the degradation of pure PCL. The degradations in biotic environment were generally faster than in abiotic environment. Higher degradation rates are observed in more complex environments (composts and anerobic sewage sludge) due to synergism between high temperature and a richer fauna of microorganisms. In the biotic environments, faster reductions in number-average molecular weight (M _n) than in weight-average molecular weight (M _w) were observed. A decrease of M _n with up to 75–80% was estimated for composted pure PCL, while similar samples in anaerobic sludge at 55°C were completely degraded in 50 days. The mechanical properties of the samples subjected to composting exhibited a more rapid enbrittlement compared to the samples subjected to abiotic hydrolysis. The observed increase in crystallinity with increasing degree of degradation is explained by crystallization made possible by chain cleavage in the amorphous phase. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 61–74, 1998     

Effect of water and oxygen traces on the cathodic stability of N-alkyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide

Although research in the field of ionic liquids for electrochemical applications has led to a deeper knowledge in their electrochemical properties, doubts in the interpretation of the experimental results are still encountered in the literature due to the poor control of the experimental conditions and/or to the limited number of experiments conducted. In this work, the effect of water and oxygen traces on the cathodic stability window of hydrophobic, air-stable ionic liquids composed of N-alkyl-N-methylpyrrolidinium (PYR_1A⁺) cations and bis(trifluoromethanesulfonyl)imide (TFSI⁻) anion, is reported. The extensive investigation performed by linear sweep voltammetry (LSV) and cyclic voltammetry (CV) indicates that the TFSI⁻ anion is cathodically stable if the ionic liquid is pure and dry. The N-alkyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ionic liquids investigated showed featureless cathodic linear sweep voltammetry curves before the massive cation decomposition took place at very low potentials.     

Processing and storage effects on anthocyanin composition and antioxidant activity of jams produced with Camarosa strawberry

Anthocyanin profiles and radical scavenging activity of Camarosa strawberry jams as affected by two processing methods (conventional/industrial) and storage conditions were evaluated. Industrial strawberry jam produced in a closed system with vacuum preserved the anthocyanin composition (the total content was 35.77 ± 2.56 mg per 100 g) when compared with conventional jam produced in an open system (3.35 ± 0.05 mg per 100 g). However, the radical scavenging activity of conventional jam was lower than that of industrial jam, as EC₅₀ was 52.99 ± 0.94 and 44.33 ± 2.47 mg mL^?1, respectively. Two‐way analysis of variance indicated a significant effect of processing method and storage time during 60 days and a significant interaction for all variables except for EC₅₀. Long‐time storage of industrial jams at ?8 °C leads to 80% reduction in anthocyanin content without loss of sensorial characteristics, whereas at room temperature the reduction was 98%, and the red colour was replaced by a brownish. Regardless of storage temperature, the radical scavenging activity of jams decreased 50–60% of its initial value.     

Elastomeric Origami: Programmable Paper‐Elastomer Composites as Pneumatic Actuators

The development of soft pneumatic actuators based on composites consisting of elastomers with embedded sheet or fiber structures (e.g., paper or fabric) that are flexible but not extensible is described. On pneumatic inflation, these actuators move anisotropically, based on the motions accessible by their composite structures. They are inexpensive, simple to fabricate, light in weight, and easy to actuate. This class of structure is versatile: the same principles of design lead to actuators that respond to pressurization with a wide range of motions (bending, extension, contraction, twisting, and others). Paper, when used to introduce anisotropy into elastomers, can be readily folded into 3D structures following the principles of origami; these folded structures increase the stiffness and anisotropy of the elastomeric actuators, while being light in weight. These soft actuators can manipulate objects with moderate performance; for example, they can lift loads up to 120 times their weight. They can also be combined with other components, for example, electrical components, to increase their functionality.     

Failure Mechanisms in Sand over a Deep Active Trapdoor

An experimental testing program was undertaken to investigate failure mechanisms induced by the active movement of a deep rectangular trapdoor underlying a granular soil. Reduced-scale models were tested under normal gravity as well as under an increased gravitational field using a centrifuge facility. Some models were used to evaluate the performance of both flexible and rigid pipes undergoing a localized loss of support. Failure mechanisms in the longitudinal direction of the models were characterized by a single, well-defined failure surface that developed within the limits of the trapdoor. However, failure mechanisms in the transverse direction of the models were characterized by multiple failure surfaces extending outside the limits of the trapdoor. Significant dilation of the soil located immediately above the trapdoor was identified in the failure of the models. The pattern of the failure mechanisms was found to be affected by the stress level and backfill density. Higher stress levels were found to lead to well-developed failure zones. The influence of backfill density was found to be more relevant in models involving flexible pipes. Pipes embedded within loose backfill were severely damaged after loss of support, while pipes embedded in dense backfill experienced negligible deformations. These results indicate that damage to pipelines caused by ground loss of support can be significantly minimized by controlling the compaction of the fill.     

Dangers of lab-plant scaleup for filters involving solidliquid systems

Many laboratory procedures have been used for predicting the size of clarifiers, thickeners, filters, and centrifuges or choosing the optimum quantity of filter-aid and flocculants. Scaleup predictions are frequently based on experiments involving small pressure and vacuum filters, compression-permeability cells, and sedimentation rates. Among major problems related to the accuracy of scaleup are: (1) unrepresentative sampling, (2) aging of suspensions with accompanying changes in properties of cakes and sediments, (3) effect of sedimentation not included in theoretical equations, (4) wall effects in small diameter filters and cells, and (5) misapplication of theory to experiment.     

Recycling of aluminum and caustic soda solution from waste effluents generated during the cleaning of the extruder matrixes of the aluminum industry

Anodising industries use a concentrated caustic soda solution to remove aluminum from extruder matrixes. This procedure produces very alkaline effluents containing high amounts of aluminum. The work reported here was focussed on recycling aluminum, as aluminum hydroxide, from these effluents and regenerating an alkaline sodium hydroxide solution. Briefly, the method comprises a dilution step (necessary for reducing the viscosity of the effluent and allowing the subsequent filtration) followed by a filtration to eliminate a substantial amount of the insoluble iron. Then, sulphuric acid was added to neutralize the waste solution down to pH 12 and induce aluminum precipitation. The purity of the aluminum salt was improved after washing the precipitate with deionised water. The characterization of the solid recovered, performed by thermogravimetric analysis, Fourier transform infrared spectroscopy and X-ray diffraction, indicated characteristics typical of bayerite. The proposal method allowed recovering 82% of the aluminum present in the wastewater with high purity (99.5%). Additionally, a sufficiently concentrated caustic soda solution was also recovered, which can be reused in the anodising industries. This procedure can be easily implemented and ensures economy by recycling reagents (concentrated caustic soda solution) and by recovering commercial by-products (aluminum hydroxide), while avoiding environmental pollution.