Antimicrobial Properties of TiO2 Microparticles Coated with Ca- and Cu-Based Composite Layers

The ability of TiO₂ to generate reactive oxygen species under UV radiation makes it an efficient candidate in antimicrobial studies. In this context, the preparation of TiO₂ microparticles coated with Ca- and Cu-based composite layers over which Cu(II), Cu(I), and Cu(0) species were identified is presented here. The obtained materials were characterized by a wide range of analytical methods, such as X-ray diffraction, electron microscopy (TEM, SEM), X-ray photoelectron (XPS), and UV-VIS spectroscopy. The antimicrobial efficiency was evaluated using qualitative and quantitative standard methods and standard clinical microbial strains. A significant aspect of this composite is that the antimicrobial properties were evidenced both in the presence and absence of the light, as result of competition between photo and electrical effects. However, the antibacterial effect was similar in darkness and light for all samples. Because no photocatalytic properties were found in the absence of copper, the results sustain the antibacterial effect of the electric field (generated by the electrostatic potential of the composite layer) both under the dark and in light conditions. In this way, the composite layers supported on the TiO₂ microparticles’ surface can offer continuous antibacterial protection and do not require the presence of a permanent light source for activation. However, the antimicrobial effect in the dark is more significant and is considered to be the result of the electric field effect generated on the composite layer.     

Human health risk of dietary intake of organochlorine pesticide residues in bovine meat and tissues from Veracruz, México

Tissue distribution patterns of organochlorine pesticides in bovine carcasses varied significantly among seasons, geographic locations and tissues. The highest concentrations of Σ-DDT during the dry season were detected in lungs from Paso de Ovejas (2,834.90μg/kg lipid) and, during the rainy season, Lindane and Σ-HCH in muscle and lung samples from Paso de Ovejas (995.80 and 1,690.10μg/kg lipid). Estimated daily intakes of γ-HCH and Σ-DDT (3.35 and 1.22μg/kg bw/day) through consumption of muscle tissues from Paso de Ovejas and Puente Nacional during the rainy season showed the highest contribution. During the rainy season the highest non-cancer Hazard Ratios estimated corresponded to γ-HCH (3.97) and Σ-DDT (4.39) detected in muscle samples from Puente Nacional. The highest Hazard Ratios of cancer risk to the 95th centile daily consumption through meat corresponded to p,p'-DDT from Alvarado (7.76E+06) and from Paso de Ovejas for γ-HCH (1.50E+05) during rainy season. The results indicate potential non- and carcinogenic risks to consumer health through meat consumption.     

Study of the effects of spray‐drying on the functionality of probiotic lactobacilli

Three probiotic lactobacilli strains were spray‐dried in 20% (w/v) skim milk and submitted to a simulated gastrointestinal digestion. Fresh or spray‐dried cultures were administered to mice for 5 and 10 days, and Immunoglobulin A (IgA)‐producing cells were enumerated in the small intestine by immunohistochemistry. Spray‐drying significantly enhanced the resistance of Lactobacillus paracasei A13 and Lactobacillus casei Nad to a simulated gastrointestinal digestion (0.96 and 1.95 log orders, respectively), compared with fresh cultures. Also, a significant higher number of IgA‐producing cells were induced by spray‐dried cultures compared with fresh cultures. Spray‐drying is a suitable, but strain‐dependent, technological process for the development of probiotic cultures in skim milk with increased functionality.     

Porous calcium alginate–gelatin interpenetrated matrix and its biomineralization potential

Artificial bone composites exhibit distinctive features by comparison to natural tissues, due to a lack of self-organization and intimate interaction apatite-matrix. This explains the need of “bio-inspired materials”, in which hydroxyapatite grows in contact with self-assembling natural polymers. The present work investigates the function of a rational design in the hydroxyapatite-forming potential of a common biopolymer. Gelatin modified through intrinsic interactions with calcium alginate led through freeze-drying to porous hydrogels, whose architecture, constitutive features and chemistry were investigated with respect to their role on biomineralization. The apatite-forming ability was enhanced by the porosity of the materials, while the presence of alginate-reinforced Gel elastic chains, definitely favored this phenomenon. Depending on the concentration, polysaccharide chains act as “ionic pumps” enhancing the biomineralization. The mineralization-promoting effect of the peptide-polysaccharide network strictly depends on the hydrogels structural, compositional and morphological features derived from the interaction between the above mentioned two components.     

YATA: Yet Another Proposal for Traffic Analysis and Anomaly Detection

Network traffic anomaly detection has gained considerable attention over the years in many areas of great importance. Traditional methods used for detecting anomalies produce quantitative results derived from multi-source information. This makes it difficult for administrators to comprehend and deal with the underlying situations. This study proposes another method to yet determine traffic anomaly (YATA), based on the cloud model. YATA adopts forward and backward cloud transformation algorithms to fuse the quantitative value of acquisitions into the qualitative concept of anomaly degree. This method achieves rapid and direct perspective of network traffic. Experimental results with standard dataset indicate that using the proposed method to detect attacking traffic could meet preferable and expected requirements.     

Prefreezing application of whey protein‐based edible coating to maintain quality attributes of strawberries

Prefreezing application of whey protein concentrate (WPC)‐based edible coating to maintain quality attributes of strawberries was studied. Beeswax (BW) was added to the solutions (0%, 20% and 40% with respect to the solids contained in the mixture WPC/glycerol). Coated and control fruits were frozen, stored at ?20 °C and thawed. After thawing, weight loss, firmness, microstructure and colour parameters were measured. Coating with 20% BW reduced strawberries weight loss after thawing (55%). Strawberries firmness was maintained equally in all groups analysed although a slight improvement at the cell microstructure alterations caused by the freezing process was observed in coated fruits. Strawberries brightness was similar in all groups. Colour parameter a* showed a tendency to decrease with the increasing BW concentration, and only b* of coated fruits was lower than controls. The application of whey protein coating could be an attractive treatment to maintain quality attributes of strawberries undergoing the freezing process.     

Evaluation of antioxidant capacity,genotoxicity and polyphenol content of non conventional foods: Prosopis flour

Fruits such as Prosopis pod have been food sources (patay, arrope, chicha or aloja) of inhabitants of arid and semi-arid lands in South America. The aims of the present study were determine some nutritional and functional properties as well as genotoxicity of flour obtained from Prosopis ripe pods that were submitted to different processing. Sucrose constituted the main sugar for flours obtained from Prosopis alba and Prosopis nigra. Decoctions and macerations showed around 2.9% and 1.4% of soluble proteins, respectively. The highest free phenolics, flavonoids and condensed tannins contents were observed in aqueous extractions with heating. None of the samples presented phytic acid levels high enough to constitute a nutritional problem. Antioxidant activity (AA) was evaluated by DPPH, ABTS and β-carotene bleaching assays. Results showed that the antioxidant potential was significantly higher in flour obtained from P. nigra pods than in that from P. alba pods, and it was also higher in aqueous extracts than in alcoholic ones. Data obtained suggests that compounds responsible for AA are thermostable; therefore, Prosopis flour might be capable of retaining a significant amount of antioxidant capacity after heating. Prosopis extracts did not show any mutagenic effect with and without metabolic activation. Prosopis flour proved to be a non conventional, novel and rich source of antioxidant compounds that could help to prevent pathologies associated with oxidative stress.     

Efficacy of different strategies to treat anemia in children: a randomized clinical trial

Background  

Anemia continues to be a major public health problem among children in many regions of the world, and it is still not clear which strategy to treat it is most effective.     

Influence of the cure level on the monomeric friction coefficient of natural rubber vulcanizates

An experimental investigation was performed in order to correlate the changes observed in dynamic modulus and loss tangent of vulcanized natural rubber with its network structure. A set of samples of natural rubber vulcanized at 413 K and 433 K for different times was prepared to achieve different network structures in the compound material. These networks were analyzed by means of solid‐state NMR techniques in order to distinguish the sulfur bridges formed during vulcanization. The crosslink density was calculated using swelling techniques for each cure condition. Dynamic mechanical tests were performed using a free decay pendulum in the range of temperatures between 213 K and 373 K and oscillating frequencies between 0.1 s^?1 and 20 s^?1. Loss tangent data were analyzed within the frame of the KMF model and the variation of the monomeric friction coefficient with the crosslink density was obtained. This variation is a consequence of the network structure formed in the different stages of the curing process. Copyright © 2004 Society of Chemical Industry     

Simulation of a spouted bed reactor for solid catalyst alkylation

A process simulator was developed to afford a better understanding of the performance of a butene-isobutane alkylation plant that uses a three-phase spouted bed reactor and a super acid solid catalyst. The mass and energy balances were numerically solved using lump of reactions and kinetic expressions previously developed. The results indicate the strong influence of the gas linear velocity and temperature in the riser and downcomer behavior that affects the activity, selectivity, and stability of the catalytic systems that cannot be predicted otherwise. The optimal operating conditions were determined for a particular catalyst and set of costs. The impacts of the recycling alkylate and isobutane to the reactor as well as the presence of hydrogen to control the coke formation are analyzed.