Using a sensitive research-grade infrared camera, we find that common facial cosmetics and lotions mask skin temperature in assays of the human forehead. We test a family of 10 commonly-used cosmetic products and find that volatile liquids and creams lower thermal skin temperature by at least 2 C for up to 5-10 min and at least 1 C for up to 20 min, respectively. Powder and cream that contains brightening agent lower indefinitely the skin temperature sensed by infrared camera. With the qualification that these experiments were performed in a controlled laboratory setting rather than the mass crowd screening environment where infrared temperature sensing of humans sees widespread use, our tests suggest that for human subjects whose face was treated with certain cosmetics and lotions, infrared-based screening for elevated facial temperature (fever) can be unreliable.

We report on the superhydrophobicity of self-organized surfaces of polyethylene (PE) nanowire arrays that are fabricated by a nano-injection moulding technique. The highly-aligned PE nanofibers with high aspect ratio are formed after the infiltration of polymer melts into the alumina nanopores by wetting action and fluid vibrational perturbation. The self-organized surfaces of polymer nanowire arrays are found to have micro-to-nanoscale hierarchical nanostructures, and have superhydrophobicity of >150° contact angles. The present superhydrophobic surfaces may be quite promising due to its simple but massive production with high quality.

Micromotors enjoy burgeoning interest but a limitation of their design is to require continuous supply of new fuel. The preponderance of extant micromotors depend, for their motion, on irradiation by light or exposure to acid in their environment.Here we demonstrate a motor that carries its own fuel internally, in this sense representing an analogue, in micron-sized objects, of the internal combustion engine. The fuel is DPCP (diphenylcyclopropenone) microcrystal, a solid-state chemical that after ignition by UV light requires no further irradiation to sustain a chemical reaction that emits carbon monoxide gas that can be used to propel the particle on which this chemical resides. It is loaded asymmetrically onto inexpensive microparticles to produce internally fueled propulsion with speed up to ∼20 μm/s over distances up to 15 times the capsule length in water. Once ignited, the motors maintain their direction of motion and move without need for light to follow their path. Possible strategies to extend the idea beyond the current proof of concept are discussed.