Characterization of coating systems by scanning electrochemical microscopy: Surface topology and blistering

Operation of the scanning electrochemical microscope used in feedback mode over a coated metal allows changes in the state of the coating surface to be monitored during immersion in aqueous electrolytes. This paper reports changes in the coating induced by specific anions in the electrolyte in situ during immersion. Significant surface roughening is observed for immersion times shorter than 1 day when the electrolyte contains chloride ions. This effect is also observed when the oxygen dissolved in the electrolytic phase is employed as redox mediator for SECM imaging. The coated system exposed to chloride-free electrolytes containing sulphate or nitrate maintains a featureless topography within the same time scale. The observed features are due to the nucleation and growth of blisters at the metal/coating interface induced by chloride ions in the environment. The implication is that ionic migration occurs simultaneously with the absorption of water by the coating already from the beginning of exposure to the aqueous environment. The unique role of chloride ions compared with sulphate or nitrate ions towards coating performance has been established at a very early stage following immersion of the sample.     

Myelodysplastic syndromes (MDS): prognostic factors and scoring systems

OBJECTIVE: To evaluate the score systems of Cassano and Sanz and suggest a new one. DESIGN: Case series. LOCATION: Teaching hospitals: EPM UNIFESP and Faculdade de Medicina de Botucatu. PARTICIPANTS: 59 patients diagnosed from 1979 to 1992. INTERVENTION: Evaluation of clinical-laboratorial data. MEASUREMENT: Statistical comparison, uni and multivariate analysis and actuarial survival curves. RESULTS: Cassano's system divided the patients into high and low risk (p = 0.0966) while Sanz's gave high, intermediate and low risk (p = 0.0108). The univariate analysis showed hemoglobin, WBC count, E/M ratio, liver size and blast percentage in BM as statistically significant. The multivariate analysis showed blast percentage in BM (p = 0.004) and Hb (p = 0.050) as significant. Our system, considering the multivariate analysis data, divided the patients into high, intermediate and low risk (p = 0.0038). CONCLUSIONS: Sanz's system was more functional than Cassano's, while ours showed predictive survival value and ease of use in clinical practice.     

Enteral feeding in the home environment

Nutritional status has a major influence on wound healing, immunity, and quality of life for home care patients. This article presents the rationale, guidelines, and troubleshooting strategies home care nurses can use in caring for patients receiving enteral nutrition.     

Surface characterization of photodegraded poly(ethylene terephthalate). The effect of ultraviolet absorbers

The surface characterization of photodegraded poly(ethylene terephthalate) was investigated. Films obtained by bi-axial extrusion were exposed in a laboratory weathering chamber for periods of up to ∼1100 h of irradiation. Samples prepared with and without an ultraviolet (UV) absorber were tested by infrared, UV-visible and fluorescence spectroscopy. The results indicated that the unstabilized films are very susceptible to the degradation effects causing a large deterioration, especially in surface layers. The presence of an ultraviolet light absorber effectively reduced the formation of carboxyl end-groups at the surface as well as in the bulk of the films. In the case of samples with UV absorber the fluorescence data showed a barrier imposed by this additive in the formation of the monohydroxy-terephthalate. Scanning electron microcopy of fracture surfaces showed that film ductility is highly reduced after exposure.     

An energy‐efficient anti‐jam cognitive system for wireless OFDM communication

In this paper, anti‐jamming capabilities are proposed for a generic OFDM‐based wireless communication system. The performance of a wireless system may severely degrade in presence of jamming or intentional interferences. A malicious entity can send strong interference or noisy signals in the same transmit frequency band thus preventing the intended receiver to correctly decode the transmitted data. As a countermeasure, our work proposes algorithms and techniques to restore the system performance in presence of such malicious entities. Proposed anti‐jamming system consists of an adaptive framework that adapts itself to varying jammer behavior and wireless environment, and then, it chooses an optimal strategy to effectively cancel out the effect of jamming and channel fading. Optimization problem is formulated as a multi‐objective criterion for maximization of system throughput and minimization of energy consumption. Simulation results computed in Rayleigh fading channels with different wideband jamming modes and powers show that the proposed system effectively cancels out the jamming and channel fading effects thus maximizing the system performance and minimizing cost of energy consumption. Copyright © 2013 John Wiley & Sons, Ltd.     

Porous stabilized zirconia coatings on zircon using volatility diagrams

A process for obtaining porous coatings of yttria stabilized zirconia on zircon substrates is described. The calcination in reducing atmospheres (oxygen partial pressures below 2 × 10^?9 atm and at temperatures over 1300 °C) of test samples containing zircon and small amounts of yttria led to the formation of porous stabilized zirconia coatings (up to 240 μm thick) on the samples. The process led to the decomposition of the silica contained in the zircon, volatilized in the form of SiO_(gas), originating pores in its place. The conditions required for the process were inferred from the volatility diagrams of the involved chemical species, which were likewise used to analyze the experimental results.     

Comparison of two varieties of microcrystalline cellulose as filler-binders I. Perdnisone tablets

A comparative study of two varieties of microcrystalline cellulose (Avicel PH 101 and Avicel PH 102) as excipients in direct compression prednisone tablets has been carried out. The effects of compression force, proportion of drug/excipient and variety of cellulose (defined by means of mean particle size) on the structural, mechanical and release properties of the tablets were studied. Differences were observed in the behaviour of the two varieties of cellulose affecting all the properties analyzed. These differences diminished, and disappeared in some cases, when 10% prednisone was present. The different degrees of interparticle association and the relations between the structural, mechanical and drug release properties of the tablets explain the differences observed.