Comb-like fluorinated polystyrenes with different side chain interconnecting groups between backbone and side chain, such as ether (PST-O), thioether (PST-S) and sulfone (PST-SO 2 ), were synthesized in order to examine the effect of the interconnecting groups on the surface order and properties. Near edge X-ray absorption fine structure spectroscopy and grazing incidence wide-angle X-ray diffraction showed that PST-SO 2 with very polar sulfone groups exhibited a lower tilt angle of the fluorinated helix to the surface normal as well as higher packing density of fluorinated alkyl side chains than PST-O and PST-S, which have less polar groups. As a result of the ordered structure at the polymer-air interface, PST-SO 2 has a smaller surface energy and better stability in water than PST-O and PST-S. These results suggest that the introduction of polar groups to the side chains of comb-like fluorinated polymers can improve the surface properties including the hydrophobicity and stability of fluorinated surfaces.

The light absorption of silica nanoparticles generated in a flame has been measured in visible light. It was revealed that the frequency dependence of the light absorption coefficient is nonexponential. Its absolute value in the forbidden band was found to be unusually high. This behavior of light absorption is ascribed to a narrowing of the energy gap due to a high concentration of structural defects that appear during particle generation and growth at high temperatures.

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An artificial muscle actuator resolves practical engineering problems in compact wearable devices, which are limited to conventional actuators such as electromagnetic actuators. Abstracting the fundamental advantages of an artificial muscle actuator provides a small-scale, high-power actuating system with a sensing capability for developing varifocal augmented reality glasses and naturally fit haptic gloves. Here, we design a shape memory alloy-based lightweight and high-power artificial muscle actuator, the so-called compliant amplified shape memory alloy actuator. Despite its light weight (0.22 g), the actuator has a high power density of 1.7 kW/kg, an actuation strain of 300% under 80 g of external payload. We show how the actuator enables image depth control and an immersive tactile response in the form of augmented reality glasses and two-way communication haptic gloves whose thin form factor and high power density can hardly be achieved by conventional actuators.

Neurotoxins contained in the seeds of Cycas micronesica K.D. Hill have been implicated in the Guam neurological disease cluster, amyotrophic lateral sclerosis-parkinsonism dementia complex (ALS-PDC). Some of these neurotoxins remain in the washed cycad seed flour that was historically an important part of the Chamorro diet. Of these, variant steryl glucosides have been identified by us as a possible etiological factor in the disease. In vitro and in vivo animal studies have strongly supported a role for these molecules in some forms of neurodegeneration. As part of a series of studies, we have now determined the concentrations of several steryl glucosides and their sterol precursors as affected by the age of C. micronesica seeds. The concentration of these molecules declined with seed age from 2.0 to 30.5 months. Following log-transformation of both axes, the decline was linear. Similarly, concentration of all but one of the molecules declined with age when samples were restricted to gametophyte tissue. Factors suspected of influencing phenotypic plasticity must be addressed when interpreting plant physiology data. Our results confirm for the first time that tissue age must be documented and reported in cycad seed biochemistry studies to remove ambiguities from results. Past studies in this important area of research have failed to account for the potential impact of seed age, rendering previous outcomes and interpretations of cycad neurotoxins in their impact on ALS-PDC ambiguous.