An interesting self-healing material was developed by Zhenan Bao and coworkers at Stanford University. It is made of a randomly branched, hydrogen-bonding polymeric network that embeds nickel microparticles that have nanostructured surfaces.
Bao and coworkers started with a mixture of polyurethanes and added as
much as 30% by volume nickel microparticles to make the polymer conductive. The polymer network forms hydrogen bonds with itself and with oxides on the surface of the nickel particles. The hydrogen bonds are the weakest bonds in the system, and they preferentially break when the composite is damaged. When cut pieces of the material are brought together, the hydrogen bonds quickly re-form.
The healing of the material is so rapid that the electrical conductivity is restored to more than 90% of its original value within 15 seconds. The mechanical properties
take a little longer. Complete healing takes 30 minutes. And the material can heal itself repeatedly, as shown by using the material as electronic skin on a doll-like mannequin. A touch sensor on the palm responds to pressure, whereas a flexion sensor at the elbow joint responds to bending. The team now seeks to make the material stretchable as well as bendable so that it will be even more like natural skin.
For more information, check out the original article at
Dieter Schramek and his Innovative Access Team (IAT) have further developed Germany‘s Transrapid system - the magnetic levitation train (or maglev) as it is normally called. They are now looking for partners and/or shareholders to make their revolutionary new traffic system a reality.
Maglev trains have the potential to solve future transportation problems by providing a clean technology, high speed transportation (up to 400 km/h) at affordable prices. The new IAT-maglev saves space, time and energy due to its construction (double decker) and innovative energy supply system. Check out this interesting system at
Monodisperse Fe3O4 and γ-
The American Society for Testing Materials, or ASTM, had published a new standard: E2834 - Standard Guide for Measurement of Particle Size Distribution of Nanomaterials in Suspension by Nanoparticle Tracking Analysis (NTA). The Standard is available from ASTM at http://www.astm.org/Standards/E2834.htm .
A unique bacterial protein selectively binds an unstable triferric citrate complex to import iron into Bacillus cereus cells, reports a team from the University of California, Berkeley (Proc. Natl. Acad. Sci. USA, DOI: 10.1073/pnas.1210131109). Iron is an essential element that bacteria commonly sequester by sending ligands, called siderophores, to chelate insoluble Fe(III) in the environment. Selective binding and transport proteins then convey the complexes back into the cells.
Common siderophores include citrate and citratebased ligands. Citrate’s carboxyl and hydroxyl groups coordinate Fe(III). Previously, however, citrate-binding proteins were observed harboring only Fe(citrate)2 and Fe2(citrate)2. Kenneth N. Raymond and colleagues have now identified a B. cereus protein, christened ferric citrate-binding protein C, or FctC, that selectively binds Fe3(citrate)3 even when other iron-citrate species are present in solution. Only a few closely related species have genes for similar proteins, so FctC may give the B. cereus group an advantage by enabling import of iron complexes that other bacteria cannot sequester.
The “12th German Ferrofluid Workshop” was held from Sept 26-28 in the Cloister Benediktbeuern close to Munich. More than 80 attendees presented 53 scientific contributions in 24 talks and a poster for each contribution. During the meeting the general assembly of the “Ferrofluid Society Germany”, which organizes this meeting and others, was held in a closed session. Because of the upcoming DFG Priority Program “Field controlled particle matrix interaction: synthesis, multi-scale modelling and application of magnetic hybrid-materials” the workshop was focused on these topics. Detailed information to the program and the abstracts of the workshop as well as for past workshops can be found here (in the frame “archive").
The next workshop will be organized in combination with the kick-off meeting of the Priority Program in the week of Sept 24-28, 2013 in the Cloister Benediktbeuern again. More information and contact addresses concerning the Priority Program are listed on the pages of the German Research Council (DFG).
Figure: Setup for experimental investigation of magnetically induced deformation of magnetic fluids presented by Jana Popp (Zimmermann group) from Technical University of Ilmenau.
Submitted by Silvio Dutz, Institute of Photonic Technology IPHT, Jena, Germany.
Dr. Thomas Tourdias and colleagues recently published a study where they investigated if a combination of gadolinium-enhanced MRI (dotarem) followed by the injection of ultrasmall superparamagnetic iron oxide particles (USPIO) (sinerem) had advantages for the assessment of disease activity in multiple sclerosis phenotypes. Very interesting and well done study, in which they found that the combination of gadolinium and USPIO in patients with MS can help identify additional active lesions compared with the current standard, the gadolinium-only approach, even in progressive forms of MS. Lesions that enhance with both agents may exhibit a more aggressive evolution than those that enhance with only one contrast agent.
To look at the details, please click here.
DNA molecule control the shape and surface properties of gold-DNA nanoparticles. The findings could be used to create nanoparticles with shapes optimized for sensing, imaging, catalysis, and other applications.
Researchers often use DNA strands to help control morphology in nanoparticle synthesis, but the process has been by trial and error. Chemical biologist Yi Lu
of the University of Illinois, Urbana-Champaign, and coworkers, including Jinghong Li’s group at Tsinghua University, in Beijing, have discovered the method to this madness in preparing gold-DNA nanoparticles. By systematically varying DNA sequences added to solutions used to make gold-DNA nanoparticles, they found that like a genetic code, specific sequences lead
to distinct particle shapes and surface characteristics ( Angew. Chem. Int. Ed., DOI: 10.1002/anie.201203716 ).
For more information, check out our Archives.