Their findings, which appear in the latest edition of Proceedings of the National Academy of Sciences, have a range of implications -- from the production of pharmaceuticals and new electronic materials to unraveling the pathways for kidney stone formation.
The researchers focused on L-cystine crystals, the chief component of a particularly nefarious kind of kidney stone. The authors hoped to improve their understanding of how these crystals form and grow in order to design therapeutic agents that inhibit stone formation.
While the interest in L-cystine crystals is limited to the biomedical arena, understanding the details of crystal growth, especially the role of defects -- or imperfections in crystals -- is critical to the advancement of emerging technologies that aim to use organic crystalline materials.
Scientists in the Molecular Design Institute in the NYU Department of Chemistry have been examining defects in crystals called screw dislocations -- features on the surface of a crystal that resemble a spiraled ham.
Dislocations were first posed by William Keith Burton, Nicolás Cabrera, and Sir Frederick Charles Frank in the late 1940s as essential for crystal growth. The so-called BCF theory posited that crystals with one screw dislocation would form hillocks that resembled a spiral staircase while those with two screw dislocations would merge and form a structure similar to a Mayan pyramid -- a series of stacked "island" surfaces that are closed off from each other.
Using atomic force microscopy, the Molecular Design Institute team examined both kinds of screw dislocations in L-cystine crystals at nanoscale resolution. Their results showed exactly the opposite of what BCF theory predicted -- crystals with one screw dislocation seemed to form stacked hexagonal "islands" while those with two proximal screw dislocations produced a six-sided spiral staircase.
A re-examination of these micrographs by Molecular Design Institute scientist Alexander Shtukenberg, in combination with computer simulations, served to refine the actual crystal growth sequence and found that, in fact, BCF theory still held. In other words, while the crystals' physical appearance seemed at odds with the long-standing theory, they actually did grow in a manner predicted decades ago.
"These findings are remarkable in that they didn't, at first glance, make any sense," said NYU Chemistry Professor Michael Ward, one of the authors of the publication. "They appeared to contradict 60 years of thinking about crystal growth, but in fact revealed that crystal growth is at once elegant and complex, with hidden features that must be extracted if it is to be understood. More importantly, this example serves as a warning that first impressions are not always correct."
The research was supported by the National Science Foundation (CHE-0845526, DMR-1105000, and DMR-1206337) and by the NSF Materials Research Science and Engineering Center (MRSEC) Program (DMR-0820341).
NYU's center is one of 27 MRSECs in the country. These NSF-backed centers support interdisciplinary and multidisciplinary materials research to address fundamental problems in science and engineering. For more, go to http://mrsec.as.nyu.edu and http://www.mrsec.org.
James Devitt | EurekAlert!
Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration
"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...
Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.
Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
16.01.2017 | Power and Electrical Engineering
16.01.2017 | Information Technology
16.01.2017 | Power and Electrical Engineering