Chemists create nanofibers using unprecedented new method, reminiscent of fibers found in living cells

Researchers from Carnegie Mellon University have developed a novel method for creating self-assembled protein/polymer nanostructures that are reminiscent of fibers found in living cells. The work offers a promising new way to fabricate materials for drug delivery and tissue engineering applications. The findings were published in the July 28 issue of Angewandte Chemie International Edition.

Chemists create nanofibers using unprecedented new method, reminiscent of fibers found in living cells -- 

"Pistachio Shell Used in Production of Wood Plastic Nanocomposite"

The nanocomposite can be used in building industry, and it is resistant to humidity, loss of color  and various types of fungi and insects.

In this research, the powder of pistachio shell was used as the filler of heavy polyethylenematrix. In addition, the effect of the presence of nano clay (cloisite 20A) and optical stabilizers was studied on tensile properties, impact, loss of color and resistance to weathering of the produced plastic wood composite.

Iran has always been among the top producers of pistachio in the world, and it annually produces and exports thousands of tons of pistachio to other countries. Therefore, it is very easy to have access to pistachio shell in the country as agricultural waste. On the other hand, the structure of pistachio shell and its components, specifically cellulose, make this material an appropriate choice for the production of composites. Pistachio shell contains cellulose, hemicelluloses and lignin.

The greatest advantage of plastic wood composite is its very good compatibility with the environment. This material is made of useless pieces of wood and recyclable plastic materials, and it has less maintenance cost in comparison with rough wood. It also has high resistance against decay, fungi and insects.

Based on the obtained results, the best increase in tensile strength and tensile module takes place when three weight sections of nanoparticles are used. When the amount increases to six, the opposite result is achieved. Tensile strength increases 27% when the amount of nanoclay increases from zero to three weight sections, while it decreases 4% when the concentration reaches six weight sections.

Nanotechnology Now - Press Release: "Pistachio Shell Used in Production of Wood Plastic Nanocomposite"

"Scientists Develop Force Sensor from Carbon Nanotubes"

The scientists proposed using two nanotubes, one of which is a long cylinder with double walls one atom thick. These tubes are placed so that their open ends are opposite to each other. Voltage is then applied to
them, and a current of about 10nAflows through the circuit.


Carbon tube walls are good conductors, and along the gap between the ends of the nanotubes the current flows thanks to the tunnel effect, which is a quantum phenomenon where electrons pass through a barrier that is considered insurmountable in classical mechanics.

This current is called tunneling current and is widely used in practice. There are, for example, tunnel diodes, wherein current flows through the potential barrier of the p-n junction.

Another example is a scanning tunneling microscope (STM), in which the surface of a sample is scanned with a very sharp needle under voltage. The needle slides along the surface, and the magnitude of the current flowing through it shows the distance to the sample with such accuracy that the STM can detect protrusions one atom high.

The authors of the article used the relationship between the tunneling current and the distance between the ends of the nanotubes to determine the relative position of the carbon nanotubes and thus to find the magnitude of the external force exerted on them.

The new sensor allows the position of coaxial cylinders in two-layer nanotubes to be controlled quite accurately. As a result, it is possible to determine the stretch of an n-scale object, to which electrodes are attached. Calculations  made by the researchers showed the possibility of recording forces of a few tenths of a nN(10-10newtons). To make it clearer, a single bacterium weighs about 10-14newtons on average, and a mosquito weighs a few dozen mcN (10-5 N).However, the device developed by the physicists may find application beyond micro scales.

A double-layered coaxial nanotube is akin to a microscopic cylinder with a sliding piston. Such a system has already been considered by a number of other researchers as a potential part for various types of nanomachines. Nanotubes have been proposed for the role of micromanipulators, or connecting "studs" for complex mechanisms, and they may even be used for data storage; the position of the inner "piston" may encode one bit of information or more.

Furthermore, calculations have shown that it is possible to create a combined device, where inside a two-layer carbon nanotube there will be magnetic fullerenes. When placed in a magnetic field, a power will emerge, which could be measured by changes in the magnitude of tunneling current. This will convert the force sensor into a magnetic field sensor.

"Scientists Develop Force Sensor from Carbon Nanotubes"