By attaching short sequences of single-stranded DNA to nanoscale building blocks, researchers can design structures that can effectively build themselves. The building blocks that are meant to connect have complementary DNA sequences on their surfaces, ensuring only the correct pieces bind together as they jostle into one another while suspended in a test tube. Now, a University of Pennsylvania team has made a discovery with implications for all such self-assembled structures. The spheres that make up the crystal follow each other in slipstreams, making some patterns more likely to form. (Ian Jenkins) Earlier work assumed that the liquid medium in which these DNA-coated pieces float could be treated as a placid vacuum, but the Penn team has shown that fluid dynamics play a crucial role in the kind and quality of the structures that can be made in this way. As the DNA-coated pieces rearrange themselves and bind, they create slipstreams into which other pieces can flow. This phenomenon makes some patterns within the structures more likely to form than others. The research was conducted by professors Talid Sinno and John Crocker, alongside graduate students Ian Jenkins, Marie Casey and James McGinley, all of the Department of Chemical and Biomolecular Engineering in Penn’s School
The post The motion of the medium matters for self-assembling particles, research shows has been published on Technology Org.
The previous atomic clock, called NIST-F1, was launched in 1999. It was accurate to within plus or minus one second over the course of 100 million years. The newly launched atomic clock, called NIST-F2, is accurate to within plus or minus one second over 300 million years.
Both clocks are based on a Cesium atom fountain. Physicists measure the frequency of a transition that the Cesium atoms make, which divides a second into 9,192,631,770 vibrations per second. NIST explains how the F2 standard is so much more accurate than the older standard:
Read 3 remaining paragraphs | Comments
A technology developed by Cornell scientists that prepares proteins for X-ray crystallography has made its way into the world marketplace: ADC Inc., a maker of scientific instruments located just outside Ithaca, has licensed the high-pressure cryocooler, called HPC-201, and has just fulfilled its first order to a research center in Japan. The licensing agreement is ADC’s first with Cornell. Company president Alex Deyhim says the product is garnering interest from potential buyers, and he’s thrilled to showcase the “amazing work” of Cornell scientists. “There is a large percentage of technologies that Cornell is developing and filing patents on, and this is a perfect example of one that can create some sales and create jobs in upstate New York,” Deyhim said. “The technology was developed, designed and built here, 10 minutes from Cornell, and we just shipped a unit across the world.” The science behind HPC-201 was developed in the lab of Sol Gruner, the John L. Wetherill Professor of Physics, who first became interested in high-pressure cryocooling of proteins in about 2002. Since then, he and a steady stream of graduate students and postdoctoral associates (most recently former MacCHESS (Macromolecular diffraction facility at Cornell High Energy Synchrotron Source) scientist Chae
The post High-pressure cryocooler that prepares proteins for X-ray crystallography has been published on Technology Org.
The promise of nanoparticles stems from their potential to modify the physical and mechanical properties of polymers for diverse applications, such as photovoltaic cells, sensors, and separation membranes. Methods currently used to create desired nanostructure, however, rely on complex and energy-intensive techniques, such as layer-by-layer or patterning approaches, which are limited in scale and often have poor stability. Publishing in Nature Communications (DOI: 10.1038/ncomms4589), Dr. Minhao Wong, a former graduate research assistant in the Polymer Technology Center of Dr. H-J Sue, Department of Materials Science and Engineering, and Dr. Ryohei Ishige of I2CNER (International Institute for Carbon-Neutral Energy Research), Kyushu University in Japan, have developed a simple approach of applying a surface coating of thin, flat nanoplatelets using a common spray gun, such as can be purchased off-the-shelf from an art supply store, to create a surface coating in which nanoplatelets spontaneously self-assemble into “nano-walls.” The nano-walls act as rigid barriers that prevent oxygen gas from reaching the surface, and are effective at low and high humidity levels. Using this scalable and simple processing method, researchers have achieved extremely fine and highly ordered nano-scale features that are conventionally achieved with complex and energy-intensive manufacturing techniques. This new technology is expected to be immediately useful
The post Researchers use common spray gun to create self-assembling nanoparticle films has been published on Technology Org.
NASA's Chandra X-ray Observatory originally shared:
