Corrosion protection of aluminium alloy by cerium conversion and conducting polymer duplex coatings

The corrosion protection of AA6063 aluminium alloy by cerium conversion, polyaniline conducting polymer and by duplex coatings has been investigated. The electrochemical behaviour was evaluated in aerated 3.5 wt.% NaCl. All coatings tested shifted the corrosion and pitting potentials to more positive values, indicating protection against corrosion. The duplex coatings are significantly more effective than each coating alone: corrosion and pitting potentials were shifted by +183 and +417 mV(SCE), respectively, by duplex coatings in relation to the untreated aluminium alloy. Optical microscopy and scanning electron microscopy are in agreement with the electrochemical results, reinforcing the superior performance of duplex coatings. (C) 2012 Elsevier Ltd. All rights reserved.

Protection of Bifidobacterium lactis and Lactobacillus acidophilus by microencapsulation using spray-chilling

The aim of this study was to produce and evaluate solid lipid microparticles containing Bifidobacterium lactis or Lactobacillus acidophilus. Survival assays were conducted to evaluate the resistance of the probiotics to spray-chilling process, their resistance to simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) and their stability during 90 d of storage. The viability of the cells was not affected by microencapsulation. The free and encapsulated cells of B. lactis were resistant to SGF and SIF. The microencapsulation, however, provided protection for L. acidophilus against SGF and SIF. The free and encapsulated microorganisms lost their viability when they were stored at 37 degrees C. However, promising results were obtained when refrigerated and frozen storage was applied. The study indicates that spray-chilling using fat as carrier can be considered an innovative technology and matrix, respectively, for the protection, application and delivery of probiotics. (C) 2012 Elsevier Ltd. All rights reserved.

Hydroxyl scavenging activity accounts for differential antioxidant protection of Plantago major against oxidative toxicity in isolated rat liver mitochondria

Objectives The aim of this work was to study the effects of P. major against the oxidative damage of isolated rat liver mitochondria. Methods The extracts were obtained using methanol (MeOH), ethyl acetate (EAc), dichloromethane (DCM), and hexane (Hex) as solvents. Key findings Hex, DCM, and EAc totally, and MeOH partially, inhibited ROS generation and lipid peroxidation of membranes induced by Fe2+ or t-BOOH. However, only MeOH was able to prevent the t-BOOH-induced glutathione and NAD(P)H oxidation. All extracts chelated Fe2+ and reduced DPP Hradicals. EPR analysis revealed that P. major exhibited potent scavenger activity for hydroxyl radicals. Conclusions The potent antioxidant activity exhibited by P. major was able to prevent oxidative mitochondrial damage, contributing to the understanding of its hepatoprotective action against ROS-mediated toxicity.

Nondetection Index of Anti-Islanding Passive Protection of Synchronous Distributed Generators

Synchronous distributed generators are prone to operate islanded after contingencies, which is usually not allowed due to safety and power-quality issues. Thus, there are several anti-islanding techniques; however, most of them present technical limitations so that they are likely to fail in certain situations. Therefore, it is important to quantify and determine whether the scheme under study is adequate or not. In this context, this paper proposes an index to evaluate the effectiveness of anti-islanding frequency-based relays commonly used to protect synchronous distributed generators. The method is based on the calculation of a numerical index that indicates the time period that the system is unprotected against islanding considering the global period of analysis. Although this index can precisely be calculated based on several electromagnetic transient simulations, a practical method is also proposed to calculate it directly from simple analytical formulas or lookup tables. The results have shown that the proposed approach can assist distribution engineers to assess and set anti-islanding protection schemes.