An alternative technique has been developed to create novel classes of optical materials and devices.
A new class of light-bending materials
Researchers from Northwestern University, USA have developed a first-of-its-kind technique for creating entirely new classes of optical materials and devices that could lead to light bending and cloaking devices.
Using DNA as a key tool, the interdisciplinary team took gold nanoparticles of different sizes and shapes and arranged them in two and three dimensions to form optically active superlattices. Structures with specific configurations could be programmed through choice of particle type and both DNA-pattern and sequence to exhibit almost any colour across the visible spectrum, the scientists report.
The technique combines an old fabrication method (known as top-down lithography) with a new one - a programmable self-assembly driven by DNA. The team is the first to combine the two to achieve individual particle control in three dimensions. The study was published online recently by the journal Science. This new method can be used to build metamaterials - materials not found in nature - for a range of applications.
Faster assembly line work
Scientists at the Technical University of Munich (TUM) have developed a novel electric propulsion technology for nanobots. It allows molecular machines to move 1,00,000 times faster than with the biochemical processes used to date. This makes nanobots fast enough to do assembly line work in molecular factories. The results appear in the journal Science.
TUM's new technology moves the machines by applying electrical fields to the DNA molecules, which have a negative charge. "By applying electric fields, we can arbitrarily rotate the arms in a plane," explains Professor Friedrich Simmel, an author of the study. His team has for the first time managed to control nanobots electrically.
Are earthquakes more likely during full moons?
On December 26, 2004, an earthquake with a magnitude of 9.1 ruptured the ocean floor off the west coast of Sumatra. The resulting tsunami was one of the deadliest natural disasters in history. And it occurred during a full moon. The Sumatra earthquake isn't the only large earthquake to have occurred beneath the moon's bright glare.
Both the 2010 earthquake in Chile and the Great Alaskan Earthquake in 1964 also happened on a conspicuous lunar date - making it tempting to argue that large earthquakes occur during the full moon. But a new study published in Seismological Research Letters finds that the connection is nothing but folklore.
To analyse the supposed link, Susan Hough, a seismologist at the US Geological Survey, scrutinised 204 earthquakes of magnitude 8 or greater over the past four centuries. She then matched those earthquakes to the lunar calendar and found that no more occurred during a full or new moon than on any other day of the lunar cycle.
During full and new moons, earth, the sun and the moon fall along a nearly straight line. This celestial alignment tugs at our planet, raising tides in the oceans and in the solid earth. That effect is far too weak to cause an earthquake on its own. But should the moon's gravitational pull tug at a fault that is close to rupturing, a temblor is not impossible.
Advancing with sound waves
Researchers from University of Illinois at Urbana-Champaign, USA have demonstrated that sound waves can be used to produce ultraminiature optical diodes that are tiny enough to fit onto a computer chip.
These devices, called optical isolators, may help solve major data capacity and system size challenges for photonic integrated circuits. Isolators protect laser sources from back reflections and are necessary for routing light signals around optical networks. In a study published in the journal Nature Photonics, the researchers explain how they use the minuscule coupling between light and sound to provide a unique solution that enables nonreciprocal devices with nearly any photonic material.
Cloning the Woolly Mammoth
Scientific research and practices are advancing at a rapid pace. Many of the breakthroughs have exceeded the expectations of our imaginations, and have forced us to grapple with challenges related to ethics. The most glaring example of this lies in the field of cloning.
Directed by Stephanie Brown, Ben Makuch and Ksenia Yurganova, Cloning the Woolly Mammoth tackles this debate by exploring the strides that researchers are making in replicating various species in their laboratories, in particular the woolly mammoth. Can advances in cloning allow us to resurrect a long extinct species like the woolly mammoth? This documentary explores the many controversial variables involved in this research and what can happen if it becomes successful. To watch it, visit www.bit.ly/2DzrwkC.