News Article | August 22, 2016
Biomaterials play a crucial role in the development of future high-performance materials. A naturally occurring example of such biomaterial, the mollusk shell, guides chemical replication processes in laboratories. Due to its complex chemical construction, however, these processes are not easy to replicate synthetically. Chemists at the University of Konstanz, in cooperation with the University of Science and Technology of China, are now the first to synthetically reproduce the structural configuration of natural mother of pearl, or “nacre.” To develop the multiscale structures in nacre, the chemists rely on calcium carbonate, chitin and silk fibroin gel as original components. Their production process creates the same structural composition and the nearly identical characteristics of the naturally occurring biomineral. The research results were published by Helmut Cölfen, professor of Physical Chemistry at the University of Konstanz, and his colleagues in the online edition of the prestigious journal Science. The key to developing nacre, which is 3,000 times more fracture resistant than the calcium carbonate it primarily consists of (95 percent), lies in the replication of the hierarchically arranged structure comprised of its particle-level components. Previous efforts to produce synthetic nacre involved attempts at replicating its layered structure. Unfortunately, the natural mineralization process, which many mollusks such as oysters or snails use for the production of nacre, could not be imitated. The researchers around Cölfen developed a new procedure where the natural components of nacre were used in consecutive layering and mineralization processes. They were able to simultaneously control the mineral structure in the nano- and micrometer range during a so-called “mesoscopic approach.” In this way, the chemists were able to create a biomineral that is almost identical to the naturally occurring nacre. The material is hard, fracture-resistant and is based on — in contrast to the results of previous production attempts — the insoluble structure of chitin, just like in the natural nacre. “The advantage of this approach is that we can substitute higher-grade components for the brittle calcium carbonate base material during the production process. This means that including mechanically superior materials instead of calcium carbonate in our manufacturing process will allow us to produce high-performance materials in the future — all based on the design of the mollusk shell and our bioinspired research,” explains Cölfen. His synthetic production process has one significant advantage over nature: It is faster. The developmental process of naturally occurring nacre takes months, if not years. Cölfen’s process takes two weeks. Cölfen has been a professor of physical chemistry at the University of Konstanz since 2010. His research focus is on crystallization and biomineralization processes. He has carried out pioneering research in the area of non-classical crystallization. Thompson Reuters counts him among the world’s 100 most influential chemists between 2000 and 2010. Cölfen is spokesperson for the Collaborative Research Centre 1214, “Anisotropic Particles as Building Blocks: Tailoring Shape, Interactions and Structures,” which carries out research on the directional properties of particles and their superstructures.
News Article | September 4, 2013
The Google Glass headset is currently in the claws of developers, but with commercial release around the corner, the tech giant has confirmed the opening of an app store in 2014. Speaking to Marketing Land, a Google spokesperson confirmed plans to open a dedicated, official application store next year, after it the scheme was first reported in the New York Times over the weekend. The author of the New York Times article writes: Google confirmed those plans with us today, but the company declined to share any additional details like if the Glass app store would be part of Google Play or separate, and if developers will be able to charge for apps by the time the store opens. (The Glass API terms of service currently demands that developers offer apps for free, a policy that can't last forever.) A 2014 launch date makes sense, considering that the Glass headset will be available commercially by then. In the meantime, a number of organizations and businesses have begun exploring how the wearable technology can be utilized; from the use of Glass in schools to assisting police forces on the street. Until an official app store is launched by the tech giant, Glass developers are able to access a number of unofficial application directories online. See also: Exploring Google Glass: A non-nerd's guide (and wish list) | Google patent hints at monetizing Glass, tracking user engagement | Can Google Glass make you a safer driver? | Google smartwatch expected following WIMM Labs acquisition | Is Google Glass suitable for schools? Google is also investigating ways that profit can be made from Glass. In a recent patent , Google documents how the headset's eye tracker could be used for a "pay per gaze" system -- charging businesses when a user's attention becomes engaged by an advert. Wearable technology is unlikely to stop there for the Cupertino, Calif.-based firm, as a recent report suggests Google has acquired WIMM Labs, a maker of technology-based wristwatches.
« Visteon showcasing advanced gesture recognition and HUD technologies at CES | Main | Fulcrum BioEnergy files LCFS application for municipal solid waste to FT diesel pathway with low CI of 37.47 g/MJ » Researchers at Tsinghua University, with colleagues from the University of Science and Technology Beijing, have discovered that the multi-reversible magnetization of ferromagnetic material can be controlled via the lithiation/delithiation reaction in a Li-ion battery by varying the discharge–charge potential at room temperature. This phenomenon couples magnetism and electrochemistry, and enables precise quantitative magnetization manipulation using an electrochemical method. An open-access paper on their discovery is published in the ACS journal Nano Letters. In their paper, they reported achieving reversible manipulation of magnetism over 3 orders of magnitude by controlling the lithiation/delithiation of a nanoscale α-Fe O -based electrode. The process was completed rapidly under room-temperature conditions. Our work reveals that magnetic properties are linked to the voltage control of LIBs. The concept of tuning physical properties using battery cycling clearly has strong potential because hundreds of active materials have already been developed as LIB electrodes. Our results indicate that in addition to energy storage LIBs, which have been under continuous development for several decades, provide exciting opportunities for the multireversible magnetization of magnetic fields.
Scientists have devised a triple-stage "cluster bomb" system for delivering the chemotherapy drug cisplatin, via tiny nanoparticles designed to break up when they reach a tumor. Details of the particles’ design and their potency against cancer in mice were published this week in PNAS. They have not been tested in humans, although similar ways of packaging cisplatin have been in clinical trials. What makes these particles distinctive is that they start out relatively large — 100 nanometers wide — to enable smooth transport into the tumor through leaky blood vessels. Then, in acidic conditions found close to tumors, the particles discharge "bomblets" just 5 nanometers in size. Inside tumor cells, a second chemical step activates the platinum-based cisplatin, which kills by crosslinking and damaging DNA. Doctors have used cisplatin to fight several types of cancer for decades, but toxic side effects — to the kidneys, nerves and inner ear — can limit its effectiveness. The PNAS paper is the result of a collaboration between a team led by professor Jun Wang, PhD at the University of Science and Technology of China, and researchers led by professor Shuming Nie, PhD, in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory. Nie is a member of the Discovery and Developmental Therapeutics research program at Winship Cancer Institute of Emory University. The lead authors are graduate student Hong-Jun Li and postdoctoral fellows Jinzhi Du, PhD, and Xiao-Jiao Du, PhD. "The negative side effects of cisplatin are a long-standing limitation for conventional chemotherapy," says Jinzhi Du. "In our study, the delivery system was able to improve tumor penetration to reach more cancer cells, as well as release the drugs specifically inside cancer cells through their size-transition property." The researchers showed that their nanoparticles could enhance cisplatin drug accumulation in tumor tissues. When mice bearing human pancreatic tumors were given the same doses of free cisplatin or cisplatin clothed in pH-sensitive nanoparticles, the level of platinum in tumor tissues was seven times higher with the nanoparticles. This suggests the possibility that nanoparticle delivery of a limited dose of cisplatin could restrain the toxic side effects during cancer treatment. The researchers also showed that the nanoparticles were effective against a cisplatin-resistant lung cancer model and an invasive metastatic breast cancer model in mice. In the lung cancer model, a dose of free cisplatin yielded just 10 percent growth inhibition, while the same dose clothed in nanoparticles yielded 95 percent growth inhibition, the researchers report. In the metastatic breast cancer model, treating mice with cisplatin clothed in nanoparticles prolonged animal survival by weeks; 50 percent of the mice were surviving at 54 days with nanoparticles compared with 37 days for the same dose of free cisplatin. Enhanced efficacy in three different tumor models demonstrate that this strategy may be applicable to several types of cancer, Jinzhi Du says. Source: Emory University
(Phys.org)—A team of researchers working at the University of Science and Technology of China has developed a new and potentially better electrocatalyst for use in converting carbon dioxide into methanoic acid, which could be used as a liquid fuel. In their paper published in the journal Nature, the team describes their new process and suggests that it may provide a path to reducing carbon dioxide emissions and thus help to slow global warming. As the planet continues to warm due in large part to carbon dioxide emissions from coal fired power plants, researchers around the world are working furiously to find a way to pull out the carbon dioxide from emissions before they are allowed to pass into the atmosphere, and to use them in some other way—one that is economically feasible. Many would like to see the carbon dioxide converted to something useful, such as a type of fuel that could be burned and used as a clean power source—that would make the process far more financially palatable. But thus far, such efforts and have not panned out, due to the huge costs involved. To convert carbon dioxide to something potentially useful currently requires subjecting it to electricity and a catalyst, a process known as electroreduction, but finding the right catalyst has been problematic, though progress has recently been made by using oxide derived nanostructures. In this new effort, the researchers tried a new approach, a four-atom thick layer of either mixed or pure cobalt and cobalt oxide. They found that the cobalt, which is not normally catalytically active for carbon dioxide, became active when arranged in a certain oxidized state. In testing their catalyst, the team found it able convert carbon dioxide to methanoic acid and that it provided better catalytic activity than other known metal or metal oxides. They are not suggesting, however, that their technique could be used in power plants right now, more that they believe they have opened the door to the idea of using metal based carbon dioxide electroreduction catalysts as a possibility for doing so. If their expectations pan out, it could mean coal fired powers plants could finally be on the path towards less harmful emissions. Explore further: Researchers report on new catalyst to convert greenhouse gases into chemicals More information: Partially oxidized atomic cobalt layers for carbon dioxide electroreduction to liquid fuel, Nature 529, 68–71 (07 January 2016) DOI: 10.1038/nature16455 Electroreduction of CO2 into useful fuels, especially if driven by renewable energy, represents a potentially 'clean' strategy for replacing fossil feedstocks and dealing with increasing CO2 emissions and their adverse effects on climate. The critical bottleneck lies in activating CO2 into the CO2− radical anion or other intermediates that can be converted further, as the activation usually requires impractically high overpotentials. Recently, electrocatalysts based on oxide-derived metal nanostructures have been shown to enable CO2 reduction at low overpotentials. However, it remains unclear how the electrocatalytic activity of these metals is influenced by their native oxides, mainly because microstructural features such as interfaces and defects influence CO2 reduction activity yet are difficult to control. To evaluate the role of the two different catalytic sites, here we fabricate two kinds of four-atom-thick layers: pure cobalt metal, and co-existing domains of cobalt metal and cobalt oxide. Cobalt mainly produces formate (HCOO−) during CO2 electroreduction; we find that surface cobalt atoms of the atomically thin layers have higher intrinsic activity and selectivity towards formate production, at lower overpotentials, than do surface cobalt atoms on bulk samples. Partial oxidation of the atomic layers further increases their intrinsic activity, allowing us to realize stable current densities of about 10 milliamperes per square centimetre over 40 hours, with approximately 90 per cent formate selectivity at an overpotential of only 0.24 volts, which outperforms previously reported metal or metal oxide electrodes evaluated under comparable conditions. The correct morphology and oxidation state can thus transform a material from one considered nearly non-catalytic for the CO2 electroreduction reaction into an active catalyst. These findings point to new opportunities for manipulating and improving the CO2 electroreduction properties of metal systems, especially once the influence of both the atomic-scale structure and the presence of oxide are mechanistically better understood.