Electromagnetic Interference Shielding Characteristics of SrTiO3 Nanoparticles Induced Polyvinyl Chloride and Polyvinylidene Fluoride Blend Nanocomposites

Journal of Inorganic and Organometallic Polymers and Materials - The current work deals with the synthesis and characterization of strontium titanate (SrTiO3) nanoparticles reinforced polyvinyl...     

Verbal and nonverbal fluency in patients with probable Alzheimer's disease.

Verbal fluency (semantic category naming and letter fluency) and nonverbal fluency (semantic category drawing and design fluency) were measured in mildly and moderately demented patients with probable dementia of the Alzheimer type (pDAT), and related to age at onset, disease duration, and disease severity. Group and individual patient analyses revealed impairments within verbal and nonverbal modalities that were most severe on semantic category fluency tasks. Detailed assessments of errors emphasized the role of compromised semantic memory in pDAT patients' impaired fluency, regardless of the modality of response. Fluency performance was related to dementia severity but not to age of onset or disease duration. It is concluded that deficits on measures of fluency in pDAT are due in large part to semantic memory impairments and that fluency may be useful for following disease progression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intersubband relaxation of hot carriers in coupled quantum wells

We compare experimental results for the photoluminescence decay in coupled quantum wells with a Monte Carlo simulation of electron and hole dynamics in this structure. The results support the assumption that the measured decay is associated with intersubband relaxation of electrons with little effect due to the holes. Quantitative agreement is found between the measured and theoretical time constants for most fields, although the theoretical values are shorter than the corresponding experimental values close to resonance.     

Photoluminescence of CdSe/ZnS core-shell quantum dots stabilized in water with a pseudopeptidic gemini surfactant

The use of pseudopeptidic gemini surfactants as stabilizers of hydrophobic quantum dots in water is discussed. Compound 1a acts as an intercalator with hydrophobic ligands of QDs transferring them from toluene to pure water yielding a fluorescent nanoparticle resistant to quenching by chloride anion (up to 0.1 M).     

Molybdate inhibition of environmental fatigue crack propagation in Al–Zn–Mg–Cu

effectively inhibits environmentally assisted fatigue crack propagation in 7075-T651 stressed during full immersion in low-chloride solution, as understood by hydrogen environment embrittlement and film rupture where -enhanced passivity reduces H production and uptake due to reduced crack hydrolysis, buffered pH, and a diffusion-barrier film. Inhibition is governed by the balance between crack tip strain rate and repassivation kinetics which establish the stability of the passive film. Inhibition is promoted by reduced loading frequency, reduced stress intensity range, increased crack tip concentration, and potentials at or anodic to free corrosion. The inhibiting effect of parallels that of , but molybdate effectiveness is shifted to a lower frequency regime suggesting the Al_xMo_yO_z passive film is less stable against crack tip deformation. For high R loading at sufficiently low frequencies fully inhibits EFCP, quantified by reduced crack growth rate to that typical of ultra-high vacuum, reduction in crack surface facets typical of hydrogen embrittlement, and crack arrest. Chromate did not produce such complete inhibition. Methods exist to incorporate molybdate or Mo in self-healing coating systems, but the complex effects of mechanical and electrochemical variables must be understood for reliable-quantitative fatigue performance enhancement.     

Model‐robust choice experiments: discussion and case study

Choice experiments are an effective way of obtaining objective information regarding the voice of the customer. They can be used to obtain the relevant customer attributes and importance rankings used in the first step of quality function deployment. They are also used extensively in marketing research. Optimal designs for choice experiments have been discussed in the literature. However, optimal designs are only optimal for a particular model. In this article we borrow ideas from quality engineering and industrial experimentation to develop designs for choice experiments that are model‐robust (in the sense that they are efficient for fitting a model involving main effects plus a few interactions that need not be specified in advance). A case study is presented to illustrate the use of a model‐robust design for a choice experiment. Two unsuspected interactions were discovered in the case study, and this discovery led to added insight regarding customer preferences and importance rankings of product attributes. These insights would not have been possible if an optimal design for the main effects model had been used. Copyright © 2011 John Wiley & Sons, Ltd.     

Characterization of an antioxidant surfactant-free topical formulation containing Castanea sativa leaf extract

Context: Inclusion of antioxidants in topical formulations can contribute to minimize oxidative stress in the skin, which has been associated with photoaging, several dermatosis and cancer.

Objective: A Castanea sativa leaf extract with established antioxidant activity was incorporated into a semisolid surfactant-free formulation. The objective of this study was to perform a comprehensive characterization of this formulation.

Materials and methods: Physical, microbiological and functional stability were evaluated during 6?months storage at 20?°C and 40?°C. Microstructure elucidation (cryo-SEM), in vitro release and in vivo moisturizing effect (Corneometer® CM 825) were also assessed.

Results and discussion: Minor changes were observed in the textural and rheological properties of the formulation when stored at 20?°C for 6?months and the antioxidant activity of the plant extract remained constant throughout the storage period. Microbiological quality was confirmed at the end of the study. Under accelerated conditions, higher modifications of the evaluated parameters were observed. Cryo-SEM analysis revealed the presence of oil droplets dispersed into a gelified external phase. The release rate of the antioxidant compounds (610?±?70?µgh^?0.5) followed Higuchi model. A significant in vivo moisturizing effect was demonstrated, that lasted at least 4?h after product’s application.

Conclusion: The physical, functional and microbiological stability of the antioxidant formulation was established. Specific storage conditions should be recommended considering the influence of temperature on the stability. A skin hydration effect and good skin tolerance were also found which suggests that this preparation can be useful in the prevention or treatment of oxidative stress-mediated dysfunctions.