(C) 2010 Wiley Periodicals, Inc. J Appl Polym
Sci 118: 332-337, 2010″
“With an atomic force microscopy, the effect of surface hydrophilicity on the nanofretting behavior of Si(100) against SiO(2) microsphere was investigated under vacuum and atmosphere conditions, respectively. The surface hydrophilicity revealed a strong effect on the motion behavior, adhesion force, friction force, and nanofretting damage of Si(100)/SiO(2) pairs. The increase in the hydrophilicity of Si(100) surface could expand the stick regime of Si(100)/SiO(2) pairs into a higher value of displacement amplitude. While the nanofretting ran in atmosphere, both adhesion and friction forces in the initial cycle would be larger when FK866 ic50 the Si (100) surface was more hydrophilic. However, because of the in situ chemical modification of SiO(2) tip in nanofretting, they might reveal a CAL-101 solubility dmso decrease with increasing nanofretting cycles. Either in vacuum or in atmosphere, the nanofretting damage was weaker when the Si (100) surface was
more hydrophobic. Because of the lack of oxygen and vapor in vacuum, the nanofretting damage on the Si(100) surface was dominated by mechanical interaction. The damage was characterized as the depression of 0.1-0.2 nm in depth on hydrophilic Si and the hillocks of 0.8-0.9 nm in height on hydrophobic Si and original Si. However, the nanofretting damage in atmosphere was much more serious, selleck kinase inhibitor which was identified as the grooves of 8-11 nm in depth on Si(100) surfaces. Analysis indicated that even if the nanofretting damage in atmosphere was the coupled results of mechanical interaction and tribochemical reaction, the tribochemical reaction played a dominated role. These results will help us to understand the effect of surface properties on nanofretting of silicon and optimize the surface treatment technology to minimize the potential nanofretting failure of microdevices in microelectromechanical system (MEMS). (C) 2010
American Institute of Physics. [doi: 10.1063/1.3463306]“
“Background: Despite growing consumer demand for organically produced foods, information based on a systematic review of their nutritional quality is lacking.
Objective: We sought to quantitatively assess the differences in reported nutrient content between organically and conventionally produced foodstuffs.
Design: We systematically searched PubMed, Web of Science, and CAB Abstracts for a period of 50 y from 1 January 1958 to 29 February 2008, contacted subject experts, and hand-searched bibliographies. We included peer-reviewed articles with English abstracts in the analysis if they reported nutrient content comparisons between organic and conventional foodstuffs. Two reviewers extracted study characteristics, quality, and data. The analyses were restricted to the most commonly reported nutrients.