Category Chemistry/Nanotechnology

How can long DNA filaments, which have convoluted and highly knotted structure, manage to pass through the tiny pores of various biological systems? This is the fascinating question addressed by Antonio Suma and Cristian Micheletti, researchers at the International School for Advanced Studies (SISSA) in Trieste who used computer simulations to investigate the options available to the genetic material in such situations. The study has just been published in PNAS, the journal of the National Academy of Sciences of the Unites States. Credit: Antonio Suma, SISSA

1. Iowa State engineers don’t need a plow to clear snow from the heated test slabs they installed at the Des Moines International Airport. Larger photo. Photos courtesy of Halil Ceylan.
2. A thermal image of the heated airport pavements.

Scheme of the local surface chemistry modification and AuNPs tracking approach. (a) Ag nanoantennas were modified overnight with 1 mM ethanolic solution of 4-NTP. Several ethanol/water washing steps were performed on each sample. (b) 4-NTP-coated antennas were immersed in 0.1 M HCl solution and illuminated for different times at their LSPR wavelength (633 nm) with a power density of 1 W cm−2. Samples were rinsed with water and immediately dipped in the activated AuNP suspension. (c) AuNPs (15 nm) coated with 11-mercaptoundecanoic acid (MUA) as a capping layer were suspended in HEPES buffer and mixed with 1 mM EDC and 1 mM NHS, and left to react for 30 min followed by two purification centrifugation steps...

The tip of a scanning tunnelling microscope (STM) above chlorine atoms that have been deliberately moved. By moving individual atoms under their microscope, scientists were able to arrange vacancies in a single layer of chlorine atoms and create atomic lattices with a predetermined electrical response. Photo Ella Maru Studio.