Influence of Temperature and Chloride Concentration on Passivation Mechanism and Corrosion of a DSS2209 Welded Joint

The passivity behavior of a 2209 duplex stainless steel welded joint was investigated using potentiodynamic polarization, Mott-Schottky analysis and EIS measurements. In order to evaluate the contribution of temperature, chloride concentration and microstructure, a sequence of polarization tests were carried out in aerated NaCl solutions selected according to robust design of a three level-three factors Taguchi L9 orthogonal array. Analysis of signal-to-noise ratio and ANOVA were achieved on all measured data, and the contribution of every control factor was estimated. The results showed that the corrosion resistance of 2209 duplex stainless steel welded joint is related to the evolution of the passive film formed on the surface. It was found that the passive film on the welded zone possessed n- and p-type semiconductor characteristics. With the increase of solution temperature and chlorides concentration, the corrosion resistance of the passive film is more affected in the weldment than in the base metal.     

The Effect of γ‐Irradiation on the Structure and Properties of Poly(propylene)/Clay Nanocomposites

The oxidative degradation of PP/OMMT nanocomposites under γ‐irradiation was studied. Changes in structure and properties resulting from γ‐exposure in the range 0–100 kGy were investigated. The results were analyzed by comparing the influence of PP‐g‐MA and pristine OMMT on the oxidation kinetics of neat PP. γ‐Irradiation in the presence of air strongly degraded the properties of PP materials, particularly for radiation doses above 20 kGy. The rate of oxidative degradation of PP/OMMT/PP‐g‐MA nanocomposites was much faster than that of neat PP. This suggests that PP‐g‐MA and pristine OMMT components behave as oxidation catalysts, leading to the formation of free radicals in the polymer matrix.

     

Alignment of a conjugated polymer onto amyloid-like protein fibrils

The amyloid-like fibril is a biomolecular nanowire template of very high stability. Here we describe the coordination of a conjugated polyelectrolyte, poly(thiophene acetic acid) (PTAA), to bovine insulin fibrils with widths of <10 nm and lengths of up to more than 10 microm. Fibrils complexed with PTAA are aligned on surfaces through molecular combing and transfer printing. Single-molecule spectroscopy techniques are applied to chart spectral variation in the emission of these wires. When these results are combined with analysis of the polarization of the emitted light, we can conclude that the polymer chains are preferentially aligned along the fibrillar axis.     

Saturated Fat Controversy: Importance of Systematic Reviews and Meta-analyses

In adults, worldwide, the number one cause of death is coronary heart disease. Current guidelines generally recommend reduced consumption of saturated fat to reduce the risk of cardiovascular disease. However, some evidence suggests that consumption of saturated fat does not increase that risk. Recently, to address the saturated fat controversy, i.e., whether or not saturated fat intake is a risk factor for cardiovascular disease, a number of systematic reviews and meta-analyses were performed. This paper aims to provide tools for understanding both. It starts with an overview of the basic principles of systematic reviews and meta-analyses. Then, it provides examples of current evidence from systematic reviews on the relationship between saturated fat intake and the risk of cardiovascular disease. Finally, based on an example from one recent systematic review, it explains how to read a meta-analysis. Continuous updating of existing reviews, as well as the development of new systematic reviews, is needed in areas in which the role of saturated fat remains unclear.     

Antioxidant capacity and phenol content of selected Algerian medicinal plants

Extracts from the bark of Fraxinus angustifolia as well as the leaves of Pistacia lentiscus and Clematis flammula have been investigated for their reducing power, inhibition of linoleic acid peroxidation and scavenging capacity on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and H₂O₂ using in vitro spectrophotometric methods. The results indicate that the best overall antioxidant capacity was shown by extracts of Pistacia lentiscus, followed by Fraxinus angustifolia and Clematis flammula.     

Effects of prenatal and/or postnatal (maternal and/or child) folic acid supplementation on the mental performance of children

It has been suggested that a deficiency in folic acid during early, critical central nervous system development may result in persistent cognitive and behavioral effects. The purpose of this systematic review was to evaluate evidence regarding whether folic acid supplementation during pregnancy and early life influences mental performance outcomes in children. The following electronic databases were searched through December 2009 for studies relevant to mental performance and folic acid: MEDLINE, EMBASE and The Cochrane Library; additional references were obtained from reviewed articles. Only randomized controlled trials (RCTs) were included. Of 8 RCTs identified, only 2 met the inclusion criteria. Both studies involved periconceptional, multivitamin-containing, folic acid supplementation. Evidence from these 2 RCTs suggests that such supplementation does not affect the postnatal mental development of infants at a mean age of 11 mo, the developmental quotient (DQ) at 2 y of age, or the intelligence quotient (IQ) and Goodenough man drawing test quotient (DrQ) at 6 y of age. We conclude that the use of multivitamin-containing folic acid supplementation during pregnancy is associated with no benefit to the mental performance of children. These findings should be interpreted with caution due to the very limited number of studies included in this systemic review.     

Thermal oxidation of tin layers and study of the effect of their annealings on their structural and electrical properties

The main objective of this article is the control of tin dioxide preparation process on glass substrate. Layers of pure tin with thicknesses of 500 and 1000 Å are first deposited. Their enrichment with oxygen is ensured by thermal annealing for 1 and 2 h in a continuous tube furnace with temperatures varying between 300 and 500 °C.The tin film formed by vacuum evaporation has tetragonal crystalline structure, and is composed of grains of various sizes separated by grain boundaries. After annealing in oxygen, the formed phases consist of a mixture of SnO and SnO₂ crystalline mixtures and sometimes amorphous tin oxide. The more the time or the temperature of annealing, the more the quantity of SnO₂ and SnO. For an annealing at 500 °C for 10 h the size of grains increases more than annealing for 2 h. This is confirmed by the study of their micrographs.The electrical resistivity of these layers, measured by the 4 point method, is correlated to the size of the oxide particles: the smaller the particle size, the lower the electrical resistivity.