Prevalence of Cyclospora sp., Cryptosporidium sp, microsporidia and fecal coliform determination in fresh fruit and vegetables consumed in Costa Rica

The presence of Cyclospora sp., Cryptosporidium sp. and microsporidia and the levels of fecal coliforms were determined in lettuce, parsley, cilantro, strawberries and blackberries acquired in local agricultural markets of the Central Valley of Costa Rica, in order to establish the possible transmission risk of these microorganisms and other pathogens from the consumption of these raw products. During the second semester of 2001 and the first of 2002, 50 different samples of each product, 25 taken in the dry season and 25 in the rainy season and coming from five different local agricultural markets were evaluated. The fecal coliforms count was done according to the technique recommended by Vanderzant & Splittstoesser. The parasite determination was done using Zielh Nielsen and Weber staining techniques from a sediment obtained through the rinse of the mentioned products, using sterile peptonated water 0.1% and centrifuging at 900 G for 15 min. One hundred per cent of vegetable samples had fecal coliforms and the greatest prevalence was obtained during the rainy season. Although all vegetables presented fecal coliforms in high concentrations, lettuce and cilantro presented statistical difference between rainy and dry season, being greater during the rainy season. Fecal coliforms were not detected in strawberries and blackberries probablydue to its low pH. All products evaluated presented, at least once, Cryptosporidium sp., Cyclospora sp. and microsporidia, showing the risk they represent to Public Health. Cryptosporidium was present in all products but strawberries. Microsporidia was present in all products except blackberries and Cyclospora was only isolated from lettuce during the dry season. These results show the importance of introducing in the country Good Agricultural Practices, especially due to the resistance of Cryptosporidium and Cyclospora to disinfecting agents.     

Biodegradation of physicochemically treated LDPE by a consortium of filamentous fungi

Samples of low density polyethylene previously subjected to physicochemical treatments–thermal treatment (TT) at 105 and 150°C or accelerated aging treatment (AAT)–were subjected to biodegradation by a consortium of four fungi during 9 months. Morphological, structural, and surface changes and mineralization were evaluated. TT samples showed decreases in the onset melting temperature (T_o), melting point (T_m), relative crystallinity (Φ), and mean crystallite size (L₁₁₀). The degradation products in all treated samples were carbonyl and double bonds groups. The biological treatment (BT) affected the properties of all treated samples. T_o at 3 months decreased with respect to sample at 0 months; the changes were higher in TT samples; the samples then remained without significant changes. Increases in Φ were observed in TT samples within a 3‐month BT, after which reductions occurred. After a 9‐month BT, increases in L₁₁₀ were registered in all samples (up to 2.6 nm). The highest mineralization value (3.26%) was obtained with the AAT. The reported changes suggested that the fungi mainly digest the amorphous phase of polyethylene in the first stage of the experiment, but later they also digest small crystals. Superficial growth of microorganisms occurred, and penetration of hyphae was observed in most oxidized samples. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 265–271, 2004     

Melt extruded nanocomposites of polybutylene adipate‐co‐terephthalate (PBAT) with phenylbutyl isocyanate modified cellulose nanocrystals

Traditional commodity polymers are widely used in several disposable or short‐life items and take hundreds of years to decompose in nature. These polymers could be replaced in several uses by biodegradable polymers, like polybutylene adipate‐co‐terephthalate (PBAT) studied in this work. For this, nonetheless, it is necessary to improve some of the PBAT properties, like mechanical resistance and barrier properties. In this work, cellulose nanocrystals (CNC) were incorporated in PBAT with this intention, through melt extrusion. Aiming to avoid CNC aggregation during the drying and extrusion process, a CNC chemical modification with phenylbutyl isocyanate was done. It was possible to obtain PBAT‐CNC melt extruded composites with an elastic modulus 55% higher and water vapor permeability 63% lower than the values of the pure polymer, without compromising PBAT biodegradation. Therefore, the composites prepared with these enhanced properties have great potential as substitutes for traditional commodity polymers. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43678.     

Anticancer and Immunomodulatory Benefits of Taro (Colocasia esculenta) Corms,an Underexploited Tuber Crop

Taro corms contain valuable bioactive molecules effective against cancer and cancer-related risk factors, such as carcinogens and biological agents, several pathophysiological conditions, including oxidative stress and inflammation, while controlling metabolic dysfunctions and boosting the immunological response. Such broad effects are achieved by the taro health-influencing compounds displaying antitumoral, antimutagenic, immunomodulatory, anti-inflammatory, antioxidant, anti-hyperglycemic, and anti-hyperlipidemic activities. Taro bioactivities are attributed to the combination of tarin, taro-4-I polysaccharide, taro polysaccharides 1 and 2 (TPS-1 and TPS-2), A-1/B-2 α-amylase inhibitors, monogalactosyldiacylglycerols (MGDGs), digalactosyldiacylglycerols (DGDGs), polyphenols, and nonphenolic antioxidants. Most of these compounds have been purified and successfully challenged in vitro and in vivo, proving their involvement in the aforementioned activities. Although these health-promoting effects have been recognized since ancient times, as well as other valuable features of taro for food profit, such as hypo-allergenicity, gluten-free, and carbohydrates with medium-glycemic index, taro crop remains underexploited. The popularization of taro intake should be considered a dietary intervention strategy to be applied to improve the overall health status of the organism and as supportive therapy to manage tumorigenesis.     

The axial dispersion of liquid solutions and solid suspensions in planar oscillatory flow crystallizers

The planar oscillatory flow crystallizer (planar-OFC) was designed with a rectangular cross-section to improve the flow and suspension of solids of conventional OFCs. Residence time distribution experiments with liquid and solid tracers were performed to assess the effect of the net flow rate, Q , the frequency, f , and the amplitude of oscillation, x₀ , on the axial dispersion of liquids, , and solids, , in three planar-OFCs with different geometries. It was found that Q and f have in general positive effects on and , and x₀ has negative effects. Furthermore, identical values of and were obtained in each crystallizer. It was also found that the interaction between Q and x₀ is the most significant one in all systems. These results show that the three crystallizers have similar axial dispersion performances with liquids and solids. This is of paramount importance for multiphase systems such as crystallization.     

Near‐Net‐Shaping Methods for Ceramic Elements of (Body) Armor Systems

Shape‐forming techniques which may be useful in producing components for body armor are reviewed. The techniques are classified in three general categories, dry, wet, and plastic. The different shaping techniques are compared based on key parameters including shape limitations, rate of production, cost, and safety. The techniques are evaluated as to their suitability to be used to produce different body armor components such as breast plates, deltoid, shin and knee protection, and helmets. Dry‐pressing is the current standard for producing “relatively flat” components such as breast plates, but performance is limited by the inherent problem associated with dry‐pressing, namely, the difficulty in producing homogeneous green bodies because of agglomerates in the powder. Plastic processing has the potential to be useful to produce more reliable “flat” components with improved performance due to high shear mixing breaking up agglomerates. Wet (colloidal) processing techniques such as gelcasting and freeze casting may be useful to produce components with high curvature and more complex shape such as helmets. Tiles or segments may be combined to produce shaped components with increased flexibility.     

Phenolic Compounds and Antioxidant Capacity of Monovarietal Olive Oils Produced in Argentina

Virgin olive oil has high levels of phenolic compounds that are highly bioavailable; these compounds are receiving considerable attention for their antioxidant activity, closely related to the prevention of non‐communicable chronic diseases. The aim of this work was to characterize the phenolic profile and antioxidant capacity of monovarietal olive oils cvs. Arauco, Arbequina, Farga and Empeltre produced in Argentina. This study focused on the relationship between the single molecules or classes of molecules quantified by SPE‐CZE, the corresponding Folin‐Ciocalteu results, and antioxidant capacity using three different tests. Fifteen compounds were simultaneously determined: tyrosol, vinylphenol, oleuropein, hydroxytyrosol, rutin, catechin, naringenin, cinnamic acid, chlorogenic acid, syringic acid, luteolin, apigenin, vanillin acid, quercetin, and caffeic acid. The phenolic contents of the monovarietal olive oils show significant differences between different varieties (p < 0.05), with positive and significant Pearson's correlation found between Folin–Ciocalteu and CZE. Besides, the correlation between the content of total polyphenols and antioxidant capacity was high for all the antioxidant assays performed. When analyzing the correlation coefficients of the different families of phenolic compounds studied, simple phenols and cinnamic acid derivatives show a higher correlation with antioxidant capacity. Thus, findings obtained in this study demonstrated that Arauco olive oil, autochthonous for Argentina, possesses the highest antioxidant/free‐radical scavenging properties, which are very likely due to the presence of high contents of phenolic compounds.     

Microstructure and High-Temperature Mechanical Behavior of Alumina/Alumina–Yttria-Stabilized Tetragonal Zirconia Multilayer Composites

Layered composites of alternate layers of pure Al₂O₃(thickness of 125 μ m) and 85 vol% Al₂O₃-15 vol% ZrO₂ that was stabilized with 3 mol% Y₂O₃(thickness of 400 μ m) were obtained by sequential slip casting and then fired at either 1550° or 1700°C. Constant-strain-rate tests were conducted on these materials in air at 1400°C at an initial strain rate of 2 × 10^-5 s^-1. The load axis was applied both parallel and perpendicular to the layer interfaces. Catastrophic failure occurred for the composite that was fired at 1700°C, because of the coalescence of cavities that had developed in grain boundaries of the Al₂O₃ layers. In comparison, the composite that was fired at 1550°C demonstrated the ductility of the Al₂O₃+YTZP layer, but at a flow stress level that was determined by the Al₂O₃ layer.