Injectable Nanogel for Diabetics Monitors Blood Glucose Levels, Secretes Insulin as Needed
Injectable nanoparticles developed at MIT may someday eliminate the need for patients with Type 1 diabetes to constantly monitor their blood-sugar levels and inject themselves with insulin.
The nanoparticles were designed to sense glucose levels in the body and respond by secreting the appropriate amount of insulin, thereby replacing the function of pancreatic islet cells, which are destroyed in patients with Type 1 diabetes. Ultimately, this type of system could ensure that blood-sugar levels remain balanced and improve patients’ quality of life, according to the researchers.
Read more: http://www.laboratoryequipment.com/news/2013/05/injected-nanogel-can-help-fight-diabetes
(via laboratoryequipment)
New Metamaterial Can Store Light, then Release It
Nakanishi and co have created a metamaterial in which each repeating unit contains two variable capacitors.
One of the capacitors is designed to absorb and radiate waves at a particular frequency while the other is designed to trap them. If the capacitors are tuned to the same frequency, any light at that frequency is absorbed and trapped. Detuning the capacitors then releases the electromagnetic waves, allowing them to continue on their way…
Impressively, Nakanishi and co have built a proof-of-principle device that does exactly this with microwaves. That’s the first time anybody has demonstrated the storage and release of electromagnetic waves using a metamaterial.
What’s more impressive, however, is that the released waves have the same phase distribution as the originals. “The electromagnetic waves were stored and released, while maintaining the phase distribution in the propagating direction,” they say.
(via First Demonstration of the Storage And Release of Light in a Metamaterial | MIT Technology Review)
Graphene Aerogel is Seven Times Lighter Than Air
Chinese material scientists have created the world’s lightest material: A graphene aerogel that is seven times lighter than air, and 12% lighter than the previous record holder (aerographite).
A cubic centimeter of the graphene aerogel weighs just 0.16 milligrams — or, if you’re having a problem conceptualizing that, a cubic meter weighs just 160 grams (5.6 ounces). The graphene aerogel is so light that an cube inch of the stuff can be balanced on a blade of grass, the stamen of a flower, or the fluffy seed head of a dandelion.
Most aerogels are produced using a sol-gel process, where a gel is dehydrated until only the aerogel remains. Some aerogels are also produced using the template method — aerographite, for example, is created by growing carbon on a lattice (template) of zinc oxide crystals — and then the zinc oxide is removed in an oven, leaving just the carbon aerogel.
To create the graphene aerogel, however, researchers at Zhejiang University use a novel freeze-drying method. Basically, it seems like the researchers create a solution of graphene and carbon nanotubes, pour it into a mold, and then freeze dry it. Freeze drying dehydrates the solution, leaving single-atom-thick layers of graphene, supported by carbon nanotubes. The researchers say that there’s no limit to the size of the container: You could make a mini graphene aerogel using this process, or a meter-cubed aerogel if you wish.
MIT and Harvard Engineers Use “DNA-Legos” To Construct Graphene Nanostructures
This news is a follow-up to an earlier post “Harvard Researchers Create Self-Assembling Nano Bricks Made of DNA.”
Engineers are now using self-assembling DNA nanobricks as a scaffold to build nanostructures out of graphene.
The MIT and Harvard researchers are essentially taking these shapes and binding them to a graphene surface with a molecule called aminopyrine.
Once bound, the DNA is coated with a layer of silver, and then a layer of gold to stabilize it. The gold-covered DNA is then used as a mask for plasma lithography, where oxygen plasma burns away the graphene that isn’t covered. Finally, the DNA mask is washed away with sodium cyanide, leaving a piece of graphene that is an almost-perfect copy of the DNA template.
So far, the researchers have used this process — dubbed metallized DNA nanolithography — to create X and Y junctions, rings, and ribbons out of graphene.
Nanoribbons, which are simply very narrow strips of graphene, are of particular interest because they have a bandgap — a feature that graphene doesn’t normally possess. A bandgap means that these nanoribbons have semiconductive properties, which means they might one day be used in computer chips.
Graphene rings are also of interest, because they can be fashioned into quantum interference transistors — a new and not-well-understood transistor that connects three terminals to a ring, with the transistor’s gate being controlled by the flow of electrons around the ring.
(via MIT and Harvard engineers create graphene electronics with DNA-based lithography | ExtremeTech)
![“Chiplets”: Xerox Introduces New Technique to 3D Print Computer Chips
[Xerox’s] new technique, known as xerographic micro-assembly, breaks down old-fashioned silicon chip designs into thousands of tiny chiplets, and then custom assembles them with an advanced and mysterious 3D printing machine. The device apparently uses microscopic electric fields to place each mote of silicon smart dust on a template in the correct position and orientation…
Xerographic printing is an extension of a related technology known as Fluidic Self Assemby (FSA), which was previously developed by Alien technology, a company that also makes RFID tags.
In FSA, the nanoblock computing elements float in solution, and are guided into holes in an appropriate substrate. The process is reminiscent of protein subunits assembling from the cytoplasm onto a lipid membrane.
Here, chiplets would basically be the electronic version of Henry Ford’s interchangeable parts system, only in this case, each part is smaller than a grain of sand.
(via Chiplets: Xerox’s grand vision for next-generation computer assembly | ExtremeTech)](http://24.media.tumblr.com/9dba1153df0b4c1eacbb5eece6e4a35d/tumblr_ml1helciCa1qgpcs1o1_500.jpg)
“Chiplets”: Xerox Introduces New Technique to 3D Print Computer Chips
[Xerox’s] new technique, known as xerographic micro-assembly, breaks down old-fashioned silicon chip designs into thousands of tiny chiplets, and then custom assembles them with an advanced and mysterious 3D printing machine. The device apparently uses microscopic electric fields to place each mote of silicon smart dust on a template in the correct position and orientation…
Xerographic printing is an extension of a related technology known as Fluidic Self Assemby (FSA), which was previously developed by Alien technology, a company that also makes RFID tags.
In FSA, the nanoblock computing elements float in solution, and are guided into holes in an appropriate substrate. The process is reminiscent of protein subunits assembling from the cytoplasm onto a lipid membrane.
Here, chiplets would basically be the electronic version of Henry Ford’s interchangeable parts system, only in this case, each part is smaller than a grain of sand.
(via Chiplets: Xerox’s grand vision for next-generation computer assembly | ExtremeTech)
Scientists spin carbon nanotube threads on industrial scale
“We finally have a nanotube fiber with properties that don’t exist in any other material,” said lead researcher Matteo Pasquali of Rice University. “It looks like black cotton thread but behaves like both metal wires and strong carbon fibers.”
The thread has ten times the tensile strength of steel and is as conductive as copper, but is flexible enough to be wound around a spool or woven. The team envisages it being used in “smart” clothing and the aerospace industry, and says that its properties will be of particular use to electronics manufacturers.”
(via openscience)
Brain Simulation: IBM’s Artificial Synapse Inches Closer to Electrochemical Properties of Actual Brain
What’s exciting about this work isn’t the short-term implications, but the long-term goals. It’s extremely difficult to model the behavior and function of a system if you can’t build a representative model of it.
The Blue Brain project is one of the world’s leading efforts to simulate neuronal structure. The last major project milestone was the simulation of a cellular mesocircuit with 100 neocortical columns and a million cells in total. Doing so required the use of an IBM Blue Gene/P, one of the most power-efficient supercomputers in existence. At present, simulating one simplified component of a rat brain requires multiple orders of magnitude more power than an organic brain uses.
And that’s why advances like this matter. The ability to modify a material’s insulative properties without applying electricity could be critical to future attempts to scale brain modeling downward.
Creating circuits that model synapse functions (even if they do so imperfectly and very simply) can help us understand how their biological counterparts function. It could dramatically reduce the power consumption (and waste heat) generated by such attempts, just as the advent of modern semiconductor manufacturing reduced computers from structures that fit into warehouses to pockets.
(via IBM takes a step towards building artificial semiconductor synapses | ExtremeTech)
Researchers Use Lasers to Cool Materials By Interfering With Motion of Atoms
Laser cooling of gases transfers some of the kinetic energy of the atoms into photons they interact with. Successful laser cooling was achieved in glasses—solids without an ordered, coherent crystal structure—by embedding rare-earth atoms in the matrix. As with gases, the excitation of the rare-earth atoms produced the cooling. However, that method won’t work for every solid.
For solids, the thermal motion of the atoms takes the form of phonons: vibrations moving through the material. Being quantum excitations, phonons behave like particles: they can collide and scatter. One way to optically cool solids, therefore, would be to “annihilate” the phonons with laser light.
(via Laser cooling of semiconductors by annihilating excitations | Ars Technica)
After millennia of additively transferring energy from one substance to another as heat, humans have learned how to directly manipulate energy states of atoms to produce net cooling.
“Neuristors” Simulating the Behavior of Neurons On Silicon
Computing hardware is composed of a series of binary switches; they’re either on or off. The other piece of computational hardware we’re familiar with, the brain, doesn’t work anything like that. Rather than being on or off, individual neurons exhibit brief spikes of activity, and encode information in the pattern and timing of these spikes. The differences between the two have made it difficult to model neurons using computer hardware. In fact, the recent, successful generation of a flexible neural system required that each neuron be modeled separately in software in order to get the sort of spiking behavior real neurons display.
But researchers may have figured out a way to create a chip that spikes. The people at HP labs who have been working on memristors have figured out a combination of memristors and capacitors that can create a spiking output pattern. Although these spikes appear to be more regular than the ones produced by actual neurons, it might be possible to create versions that are a bit more variable than this one. And, more significantly, it should be possible to fabricate them in large numbers, possibly right on a silicon chip.
(via “Neuristor”: Memristors used to create a neuron-like behavior | Ars Technica)
Researchers Mimic Cellular Structure of Plants to Nanoengineer Better Electrode
Essentially a network of tiny wires, it features a larger surface area than flat electrodes, giving it the leverage it needs to convert more electricity in a smaller form factor. This could lead to cheaper cell production and good things for the future of green energy. “This novel electrode coating technique has applications for fuel cells in the newest generation of hybrid cars, photovoltaic cells, rechargeable batteries or battery production for a wide range of green technologies,” said the university’s Dr. Adam Squires.
Nanowire Networks from Adam Squires on Vimeo.
(via Nature-inspired nano-material builds a better electrode, points to greener future (video))
