Showing Spotlights 1513 - 1520 of 2285 in category All (newest first):
Increasing the efficiencies of polymer-based solar cells while at the same time keeping production complexity and cost low will require the preparation of new classes of polymers that can be prepared with a minimum of synthetic steps. Combining strong electron acceptors such as fullerenes (C60) with commodity polymers to make electronically active polymers promises to be one possible route. So far, though, the photovoltaic efficiencies of polymer/C60 blends are generally not as good as those for photovoltaic devices made from the currently used main classes of polymers, P3HT and PCBM. Researchers in France came up with a way to very simply prepare polymers from fullerenes without having to strongly change the aromaticity of the C60 sphere. This means that many of the original properties of C60 may be found to be retained even when combined with the beneficial properties of polymers.
May 29th, 2009
Theoretical studies have long predicted that the exceptional physical and chemical properties of a rigid monatomic linear chain of carbon atoms could function as the component of molecular devices, for instance in nanoelectronics. The problem has been that there was no reliable and effective way to produce these carbon chains and therefore scientists couldn't study them experimentally. While linear carbon chains have been already prepared either in solution or by vaporizing graphite, researchers in Japan have for the first time succeeded to derive the carbon atomic chains from graphene in a well controlled manner. This approach to realize freestanding carbon atomic chains employs energetic electron irradiation inside a transmission electron microscope.
May 28th, 2009
In a recent Nanowerk Spotlight we reported on a single molecule approach to directly visualize and map protein binding sites on DNA using fluorescent quantum dots. One of the challenges the researchers in this work had was to measure distances between probes bound to combed DNA with nanometer resolution. Whereas very short distance (below 10 nm) can be assessed by FRET measurements and distances above the Rayleigh criterion can be measured, say, with a standard microscopy picture and a ruler, distances in between need to be addressed differently. This is were a novel approach by scientists at UCLA fills the gap, and, as they claim, better than other techniques do.
May 27th, 2009
A major concern in microbiology is to determine whether a bacterium is dead or alive. This crucial question has major consequences in food industry, water supply or health care. While culture-based tests can determine whether bacteria can proliferate and form colonies, these tests are time-consuming and work poorly with certain slow-growing or non-culturable bacteria. They are not suitable for applications where real-time results are needed, e.g. in industrial manufacturing or food processing. A team of scientists in France has now discovered that living and dead cells can be discriminated with a nanotechnology technique on the basis of their cell wall nanomechanical properties.
May 26th, 2009
A recent report gives an overview of how five jurisdictions (US, UK, EU, Australia and Canada) reacted to the recent emergence of nanotechnology-based products in the marketplace and it describes how this triggered activities in three domains: (a) public and stakeholder debate, (b) development of initial policy options, and (c) the management of regulatory development in a situation of scarce data. The bulk of the report describes the current situation (up to March 2009) in the five jurisdictions and this part doesn't contain information that hasn't already been covered elsewhere. In analyzing this data, however, the authors make some interesting observations and attempt to develop a set of six key regulatory governance principles that they propose for consideration by regulators.
May 25th, 2009
In a previous Nanowerk Spotlight we have reported about the work of Chinese scientists who demonstrated that a sheet of carbon nanotube (CNT) thin film could be a practical magnet-free loudspeaker simply by applying an audio frequency current through it . The team has now reported that their CNT films can also work as an incandescent display, driven by a simple addressing circuit with response times faster than that of liquid crystal displays (LCDs). At the same time, the incandescent light of the CNT film is almost nonpolarized, and will not have the viewing-angle problem of LCDs. The CNT films in vacuum can be heated to incandescence and cooled down in about 1 millisecond by turning on and shutting off the heating voltage.
May 22nd, 2009
The prospect of stretchable electronics opens some exciting possibilities - for instance, think about artificial skin with an integrated, stretchable touchscreen display. To get there, researchers have begun developing elastic electrical wiring that is both highly conductive and highly stretchable. Currently existing stretchable materials do already exhibit excellent conductivity and mechanical stretchability but they have one major disadvantage: their manufacturing processes are not readily scalable, which means it is difficult or cost-prohibitive to apply them to large-area electronics. A research team in Japan has now successfully fabricated, for the first time, novel elastic conductors that can be directly patterned by printing processes. This novel, printable elastic conductor comprises single-walled carbon nanotubes uniformly dispersed in a highly elastic fluorinated copolymer rubber.
May 20th, 2009
Proteins that bind to specific sites of DNA are essential to all biological functions of DNA. These DNA-binding proteins include transcription factors which modulate the process of transcription, various polymerases, nucleases which cleave DNA molecules, and histones which are involved in chromosome packaging in the cell nucleus. Developing methods to precisely determine the locations and occupancy of DNA-binding proteins is instrumental to scientists' understanding of cellular processes like gene expression and regulation. Motivated by the desire to overcome some of the inherent limitations of existing biochemical techniques for mapping protein binding sites on DNA, scientists at UCLA have now demonstrated the viability of a single molecule approach to directly visualize and map protein binding sites on DNA using fluorescent quantum dots, allowing multicolor, nanometer-resolution localization.
May 19th, 2009