Development of new poly(ϵ‐caprolactone)/chitosan films

This study reports for the first time the production of poly(?‐caprolactone)/chitosan (PCL/CHT) films by solvent casting using a mixture of formic acid/acetone (70:30 vol%). Both uncrosslinked and crosslinked films with the natural crosslinker genipin were developed. The mechanical properties of the samples were analyzed by dynamical mechanical analysis (DMA) in the hydrated state. DMA was also successfully used for the first time to monitor in situ the crosslinking process as a function of time and crosslinker concentration. The compatibility between the polymers in the blended films was analyzed by Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). It was found that phase distribution is highly dependent on the blend composition. The developed films could potentially be used in different applications, such as tissue engineering scaffolds. © 2013 Society of Chemical Industry     

The effect of transglutaminase from Streptomyces sp. CBMAI 837 on the gelation of acidified sodium caseinate

The influence of the transglutaminase (TG) from a newly isolated Brazilian Streptomyces sp. CBMAI 837 and sodium caseinate concentration (4% and 8%, w/w) on acid-gel properties was studied. Standard gels with and without commercial transglutaminase samples were tested in parallel. The mechanical properties of the samples (stress and strain at rupture and elasticity modulus) were evaluated using uniaxial compression measurements. Texture parameters showed that the commercial TG gels had greater values of elasticity modulus, while addition of the Streptomyces sp. CBMAI 837 TG to the gel led to the formation of less elastic, but more deformable gels. The electrophoresis results showed that the commercial TG enzyme in this system promoted higher molecular mass protein polymers than the enzyme from Streptomyces sp. CBMAI 837. Microscopy and water-holding capacity (WHC) observations showed that all the gel characteristics could be associated with specific interactions promoted by each TG tested.     

Biological treatment of propanil and 3,4-dichloroaniline: Kinetic and microbiological characterisation

Propanil (3,4-dichloropropionanilide) is a widely used herbicide, applied worldwide in rice paddies. Propanil is primarily transformed in nature to 3,4-dichloroaniline (DCA), which is more slowly biodegradable. Both compounds have adverse health and ecotoxicity effects. This work investigated the microbial ecology and kinetics of propanil-degrading enrichments obtained from soil in a sequencing batch reactor (SBR) operated with different feeding strategies, aiming at the enhanced biological removal of propanil and DCA from contaminated waters.During SBR operation with a dump feeding strategy, a high propanil concentration led to DCA accumulation, which was only fully degraded after 5 days, likely due to DCA inhibition. For this reason, the operational mode was changed to fed-batch operation with lower initial propanil concentrations, which resulted in faster propanil and DCA biodegradation. Thus a fed-batch operation seems more appropriate for the acclimatisation of an effective propanil- and DCA-degrading population.The changes in performance were accompanied by a shift in the microbial population structure, as determined by DGGE of the 16S rRNA gene, particularly after a feed of DCA as the sole carbon source. Isolates obtained from the acclimatised population included members of the genera Enterococcus and Rhodococcus, as well as Brevundimonas, which displayed >90% propanil biodegradation efficiency.     

Effect of ageing and μ-calpain markers on meat quality from Brangus steers finished on pasture

Brangus steers (n = 247) finished on pasture were used to evaluate the effects of post-mortem ageing and polymorphism CAPN1 316 and CAPN1 4751 markers on meat tenderness and objective colour measurements (CIEL*a*b*) of m. Longissimus dorsi. Ageing meat for 7 days decreased shear force (SF) by 13.7% and improved a* (8.4%) and b* (10%) compared to ageing for 1 day. No difference between 7 and 14 days of ageing was found for SF, a* and b*. However, L* increased markedly with ageing. Fitting both markers simultaneously, CAPN1 316 showed association with SF and L* and CAPN1 4751 with a* and b*. Fitting the markers individually, CAPN1 4751 affected all traits and CAPN1 316 showed association with SF and L*. Post-mortem ageing and the use of markers represent two independent and alternative tools that could be used for improving quality of meat from Brangus cattle.     

Dietary Free Oleic and Linoleic Acid Enhances Neutrophil Function and Modulates the Inflammatory Response in Rats

The high ingestion of oleic (OLA) and linoleic (LNA) acids by Western populations, the presence of inflammatory diseases in these populations, and the importance of neutrophils in the inflammatory process led us to investigate the effects of oral ingestion of unesterified OLA and LNA on rat neutrophil function. Pure OLA and LNA were administered by gavage over 10 days. The doses used (0.11, 0.22 and 0.44 g/kg of body weight) were based on the Western consumption of OLA and LNA. Neither fatty acid affected food, calorie or water intake. The fatty acids were not toxic to neutrophils as evaluated by cytometry using propidium iodide (membrane integrity and DNA fragmentation). Neutrophil migration in response to intraperitoneal injection of glycogen and in the air pouch assay, was elevated after administration of either OLA or LNA. This effect was associated with enhancement of rolling and increased release of the chemokine CINC-2αβ. Both fatty acids elevated l-selectin expression, whereas no effect on β₂-integrin expression was observed, as evaluated by flow cytometry. LNA increased the production of proinflammatory cytokines (IL-1β and CINC-2αβ) by neutrophils after 4 h in culture and both fatty acids decreased the release of the same cytokines after 18 h. In conclusion, OLA and LNA modulate several functions of neutrophils and can influence the inflammatory process.     

Experiments and Simulations of Laminar Forced Convection With Water–Alumina Nanofluids in Circular Tubes

This work reports fundamental experimental-theoretical research related to heat transfer enhancement in laminar channel flow with nanofluids, which are essentially modifications of the base fluid with the dispersion of metal oxide nanoparticles. The nanofluids were synthesized by a two-step approach, using a dispersant and an ultrasound probe or a ball mill for alumina nanoparticles dispersion within the aqueous media. The theoretical work involves the proposition of an extension of the thermally developing flow model that accounts for the temperature variation of all the thermophysical properties, including viscosity and the consequent variation of the velocity profiles along the thermal entry region. The simulation was performed by making use of mixed symbolic-numerical computation on the Mathematica 7.0 platform and a hybrid numerical-analytical methodology (generalized integral transform technique, GITT) in accurately handling the governing partial differential equations for the heat and fluid flow problem formulation with temperature dependency in the thermophysical properties. Experimental work was also undertaken based on a thermohydraulic circuit built for this purpose, and sample results are presented to verify the proposed model. The aim is to confirm that both the constant properties and temperature-dependent properties models, besides available correlations previously established for ordinary fluids, provide adequate prediction of the heat transfer enhancement observed in laminar forced convection with such nanofluids and within the experimented Reynolds number range.     

Roasting-induced changes in arabinotriose,a model of coffee arabinogalactan side chains

Thermal processing can promote reactions that change the structure of food constituents, often by unknown mechanisms, such as those occurring in arabinose residues of coffee arabinogalactan side chains. Aiming to know more about these modifications, the structurally related α-(1 → 5)-l-arabinotriose was roasted at 200 °C and the products obtained were identified by ESI-MS and MALDI-MS and characterised by ESI-MSⁿ. Depolymerised and polymerised oligosaccharides with up to 16 residues and new types of linkages were formed. Also, products resulting from dehydration, oxidation, and cleavage of a carbon–carbon bond at the reducing end of the corresponding non-modified oligosaccharide were formed, probably promoting the release of formaldehyde, formic acid, glycolaldehyde, glyoxal, acetic acid, glycolic acid, glyceraldehyde, 2-hydroxypropanedialdehyde and lactic acid. As many of these compounds have been reported to occur in roasted coffee beans and/or brews, it can be suggested that the degradation of coffee arabinogalactan side chains can contribute to their formation upon roasting.     

Brazilian hybrid electric-hydrogen fuel cell bus: Improved on-board energy management system

The present paper unveils the technology developed for a series hybrid battery-dominant electric-hydrogen fuel cell plug-in city bus. It possesses a homemade power train with three electric energy sources, which are the grid-charged energy, the one produced by the fuel cell that works at constant power and acts as a range extender and that resultant from the regeneration of kinetic energy. Emphasis was given to the design of the hybridization energy engineering that has predominance of power in batteries and predominance of energy with hydrogen. The remarkable amount of 46.6% of the total energy input reaches the motor axle for effective motion and a fuel economy of 6.7 kg H₂/100 km was achieved. A total owner cost analysis has shown that computation of capital, operational and fueling costs makes the present bus 133% more expensive than a conventional diesel powered one. Commercialization prospects, and also social and environmental impacts are analyzed.