78 research outputs found
Active microrheology and simultaneous visualization of sheared phospholipid monolayers
Two-dimensional films of surface-active agents—from phospholipids and proteins to nanoparticles and colloids—stabilize fluid interfaces, which are essential to the science, technology and engineering of everyday life. The 2D nature of interfaces present unique challenges and opportunities: coupling between the 2D films and the bulk fluids complicates the measurement of surface dynamic properties, but allows the interfacial microstructure to be directly visualized during deformation. Here we present a novel technique that combines active microrheology with fluorescence microscopy to visualize fluid interfaces as they deform under applied stress, allowing structure and rheology to be correlated on the micron-scale in monolayer films. We show that even simple, single-component lipid monolayers can exhibit viscoelasticity, history dependence, a yield stress and hours-long time scales for elastic recoil and aging. Simultaneous visualization of the monolayer under stress shows that the rich dynamical response results from the cooperative dynamics and deformation of liquid-crystalline domains and their boundaries
Behavior and Impact of Zirconium in the Soil–Plant System: Plant Uptake and Phytotoxicity
Because of the large number of sites they pollute, toxic metals that contaminate terrestrial ecosystems are increasingly of environmental and sanitary concern (Uzu et al. 2010, 2011; Shahid et al. 2011a, b, 2012a). Among such metals is zirconium (Zr), which has the atomic number 40 and is a transition metal that resembles titanium in physical and chemical properties (Zaccone et al. 2008). Zr is widely used in many chemical industry processes and in nuclear reactors (Sandoval et al. 2011; Kamal et al. 2011), owing to its useful properties like hardness, corrosion-resistance and permeable to neutrons (Mushtaq 2012). Hence, the recent increased use of Zr by industry, and the occurrence of the Chernobyl and Fukashima catastrophe have enhanced environmental levels in soil and waters (Yirchenko and Agapkina 1993; Mosulishvili et al. 1994 ; Kruglov et al. 1996)
Characterizing the Epidemiology of the 2009 Influenza A/H1N1 Pandemic in Mexico
Gerardo Chowell and colleagues address whether school closures and other social
distancing strategies were successful in reducing pandemic flu transmission in
Mexico by analyzing the age- and state-specific incidence of influenza morbidity
and mortality in 32 Mexican states
How well suited are current thermodynamic models to predict or interpret the composition of (Ba,Sr)SO4 solid-solutions in geothermal scalings?
Elaeis guineensis-activated carbon for methylene blue removal: adsorption capacity and optimization using CCD-RSM
Performances of purified indigenous Leifsonia sp. and its mechanism in the removal of Cr(VI) under shaking condition
Magnesium oxide entrapped Polypyrrole hybrid nanocomposite as an efficient selective scavenger for fluoride ion in drinking water
Hydrochemical characteristics of shallow groundwater in aquifer containing uranyl phosphate minerals, in the Köprübaşı (Manisa) area, Turkey
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