Showing Spotlights 1153 - 1160 of 2140 in category (newest first):
Silver nanoparticles are one of the most extensively used type of nanoparticles in consumer products due to the unique antibacterial activity of silver. There have been raising environmental concerns over their adverse ecological effects, along with ionic silver potentially released from the particles. To predict the environmental impact of engineered silver nanoparticles, their characterization from environmental matrices should be pursued, yet no field-scale studies are available to date. A new research report was motivated by the fact that silver nanoparticles in consumer products are likely being released during and/or after the product's lifetime. The silver nanoparticles will likely get into wastewater streams and subsequently enter wastewater treatment plants. During wastewater treatment processes, silver nanoparticles may be incorporated into the sewage sludge matrix and concentrated over time.
Oct 4th, 2010
One of the (many) major challenges in getting closer to realizing visions of skillful nanomachines and ubiquitous nanofactories is the construction of synthetic nanomotors and other nanoscale propulsion systems that power these devices. At issue is not only the small scale of these systems but also the ability to precisely control their motion. Complicating the issue is that navigation principles used in the macroscale world are not applicable for nanoscale propulsion. The precise navigation of nanoscale objects is extremely challenging because of the combination of Brownian motion (random movement of particles) and low Reynolds number (where viscous forces dominate). Researchers in Germany have now demonstrated artificial water-walking devices in the form of self-powered microstriders at the air-liquid interface made of rolled-up catalytic microtubes.
Sep 30th, 2010
Gold-based nanostructures and carbon nanotubes have been successfully applied for photoacoustic imaging and photothermal treatment of tumors. Medical researchers believe that such nanoparticle-mediated, image-guided cancer therapy has tremendous promise for increasing the efficacy of cancer treatment while reducing toxic side effects traditionally associated with treatment. Working with a different carbon nanomaterial, researchers now have been able to show that polyhydroxy fullerenes can be utilized for the same purposes. The minute size and biocompatibility of polyhydroxy fullerenes make them particularly attractive for biomedical applications - they are water-soluble, biodegradable, antioxidant, and rapidly excreted.
Sep 29th, 2010
As technology keeps getting faster and smaller, the computer industry is working towards the end of the Moore's Law roadmap where technology will eventually be designed and created at the atomic level. Rather than working their way down incrementally, some researchers are taking a different approach by exploring what happens at the end of Moore's Law, specifically whether it is possible to do computing and other work at that scale. This means they are asking questions like, 'how many atoms are needed to store information', and 'are there schemes to do computation with magnetic atoms instead of transistors'? An IBM research team has now demonstrated, for the first time, the ability to measure how long an individual iron atom can hold magnetic information. They show how a scanning tunneling microscope can measure electron spin relaxation times of individual atoms adsorbed on a surface with nanosecond time resolution using an all-electronic pump-probe measurement scheme.
Sep 28th, 2010
Traditionally, battery materials have been studied with bulk quantities in a complex environment with both active electrode components and many other supporting materials such as polymer binders and conductive additives. Although nanomaterials have been found to be able to improve battery performance, the complexity has made it hard to tell clearly about their advantages. Moreover, it is difficult to know whether fast capacity fading is due to the intrinsic nature of the transport property changes of active nanomaterials or an extrinsic reason from their interactions with the supporting materials, if all of them are studied together. The goal to understand the intrinsic reason of active material capacity fading has motivated a group of researchers to design single nanowire electrochemical devices as an extremely simplified model system to push the fundamental limits of the nanowire materials for energy storage applications. The result is a powerful and effective diagnostic tool for property degradation of lithium ion based energy storage devices.
Sep 27th, 2010
In nature, uni- and multicellular organisms are capable of reducing and accumulating metal ions as detoxification and homeostasis mechanisms when exposed to metal ion solutions. Although the exact mechanisms and identities of microbial proteins associated for metal nanoparticle synthesis are not clear, two cysteine-rich, heavy metal-binding biomolecules, phytochelatin and metallothionein have been relatively well characterized. Phytochelatins are peptides that are synthesized by the protein phytochelatin synthase and that can form metal complexes with cadmium, copper, silver, lead and mercury, while metallothioneins are gene-encoded proteins capable of directly binding metals such as copper, cadmium, and zinc. This capability of phytochelatin and metallothionein - having different metal binding affinities to various metal ions - has now been employed by researchers for the in vivo biosynthesis of metal nanoparticles by recombinant Escherichia coli.
Sep 24th, 2010
Imagine cellular phones that can be charged during conversations and sound-insulating walls near highways that generate electricity from the sound of passing vehicles. A number of approaches for self-powering systems by scavenging energy from environments using photovoltaic, thermoelectric, and piezoelectric phenomena have been intensively explored. Among them, very recent innovative research has been intensively carried out to convert external mechanical stimuli such as body movements, heartbeat, blood flow, and ultrasonic wave into electricity, resulting in piezoelectric power-driven wireless self-powered systems. Such a piezoelectric power generation aims to capture the normally wasted energy surrounding a system and converts it into usable energy for operating electrical devices. New work by a nanotechnology research team in Korea has now demonstrated that it is possible to use sound as a power source to drive nanogenerators based on piezoelectric nanowires.
Sep 23rd, 2010
Nature can provide very useful templates for technical applications. A group of scientists have devised a new process involving the almost complete conversion of a leaf skeleton into magnetic iron carbide. To do this, they treated the leaf with iron acetate, nitrogen and heat. This technique can be used to recreate all natural carbonaceous structures with metal carbides. The result is not just beautiful, but also very useful. The new technique enables the conversion of metal carbides into intricate microstructures in just one step. Biology's intricate forms provide a wide range of templates for a variety of applications. Wide-ranging biological forms can be used as templates for filigree metal carbide structures using this method.
Sep 22nd, 2010