Half-Synthetic Half-Biological Material Replaces Soft Facial Tissues, Letting Doctors Shape Implants to Order

By Clay Dillow

A New Kind of Facelift A new injectable biomaterial from Johns Hopkins researchers can replace soft facial tissues like cheeks and lips that previously were very difficult to cosmetically repair. BestInPlastics via Wikimedia

In reconstructive surgery, if a doctor needs a bone he or she can turn to a range of plastics, ceramics, or metals as suitable replacements. But when it comes to soft tissues--like the kind found in that most cosmetically important area, the face--replacements are scarce, and the ones that do exist aren’t very good, especially when it comes to fixing large-scale deformities.

But a new transplantable biomaterial, part biological and part synthetic, could help surgeons rebuild even the hardest to fix disfigurements. Just inject, shape, and blast with green light.

The material, developed by researchers at Johns Hopkins University, blends polyethylene glycol, a synthetic material, with hyaluronic acid, a biological material already in use in soft tissue replacement. It’s injectable, so it requires no surgery, and it’s pliable, so doctors can sculpt it into the proper shape after it has been injected. A specific wavelength of green LED light then solidifies the liquid polymer where it sits, turning the biomaterial's chaotic arrangement of polymer chains into a rigid structure.

The material is also tunable. In lab tests, the researchers mixed various cocktails with different ratios of hyaluronic acid and polyethylene glycol, resulting in implants with different characteristics of pliability and durability--characteristics that would allow doctors to customize the biomaterial for any particular implant. Durability is important, because the implants are not permanent. In those lab tests, the implant with the most longevity only lasted about 500 days before the rat that was hosting it completely absorbed it into its body. That means patients would need to replace their implants roughly every year or so.

The good news is, the absorption of the material has thus far shown no real adverse effects in the rats, or even in humans. The researchers have already tested their biomaterial in three human subjects in Canada. The implants lasted about three months, and none of the subjects experience any unexpected side effects, save a little inflammation around the site of the implant.

Photovoltaic Breakthrough Lets Engineered Materials Emit More Blackbody Radiation Than Physics Says They Should

Metamaterials to the rescue once again

By Clay Dillow

Blackbody Radiation from Metamaterials Confused about blackbody radiation? Just check out this helpful diagram. Physical Review Letters

Metamaterials as a class get a lot of press for their ability to exhibit a negative refraction index, the characteristic that lets them bend light around a space or object (the much ballyhooed“invisibility cloak”). But designer metamaterials have potential reaching far beyond just visible light. They can be customized to have all sorts of tailored responses to radiation, and thanks to a Duke University research team, one of those responses could have a huge impact on thermophotovoltaics and other energy conversion schemes.

The team has demonstrated the ability to use metamaterials to engineer emitted “blackbody” radiation with an efficiency that surpasses the natural limits that should be imposed on the material by its temperature. In English, that means better energy conversion efficiency in things like photovoltaics and possibly waste heat harvesting.

A “black body” is an idealized material that absorbs all radiation that strikes it regardless of wavelength. It also emits that energy based on the material’s temperature. Black bodies don’t exist in nature, which is too bad because they are really efficient, in that they achieve a kind of equilibrium. What goes in as electromagnetic radiation comes out as thermal radiation (or “blackbody radiation”). Ideally speaking.

What the duke team has shown using metamaterials--man-made materials not found in nature--is that they can tailor that blackbody radiation in various ways, including in ways that defy the efficiency that a material would have naturally. Put another way, there is a natural limit on the radiation a given material can emit, and that limit depends on the material’s temperature. But the Duke team has shown its metamaterials can emit radiation at efficiencies beyond what nature says they should be able to (more detail on the science behind this hereand here).

The takeaway: a new class of metamaterials could lead to technologies that can harvest waste heat from industrial processes or other heat emitters at unprecedented efficiencies (read: efficiencies that actually make such energy harvesting schemes worthwhile). Or they could lead to thermophotovoltaic cells that can tailor the emitted photons to match the band gap of the semiconductor on the cell, making energy conversion far more efficient.

New Geographic Data Analysis Gives Historians a Futuristic Window Into the Past

"Spatial humanities," the future of history

By Rebecca Boyle

Gettysburg Battlefield Visitors to the Gettysburg battlefield will see some undeveloped vistas like this one, but they won’t see what Robert E. Lee saw, because time has altered the landscape. New analysis with geographic information software has allowed historians to virtually reconstruct what the scene looked like in July 1863. Wikimedia Commons

Even using the most detailed sources, studying history often requires a great imagination, so historians can visualize what the past looked and felt like. Now, new computer-assisted data analysis can help them really see it.

Geographic Information Systems, which can analyze information related to a physical location, are helping historians and geographers study past landscapes like Gettysburg, reconstructing what Robert E. Lee would have seen from Seminary Ridge. Researchers are studying the parched farmlands of the 1930s Dust Bowl, and even reconstructing scenes from Shakespeare’s 17th-century London.

But far from simply adding layers of complexity to historical study, GIS-enhanced landscape analysis is leading to new findings, the New York Times reports. Historians studying the Battle of Gettysburg have shed light on the tactical decisions that led to the turning point in the Civil War. And others examining records from the Dust Bowl era have found that extensive and irresponsible land use was not necessarily to blame for the disaster.

GIS has long been used by city planners who want to record changes to the landscape over time. And interactive map technology like Google Maps has led to several new discoveries. But by analyzing data that describes the physical attributes of a place, historians are finding answers to new questions.

Anne Kelly Knowles and colleagues at Middlebury College in Vermont culled information from historical maps, military documents explaining troop positions, and even paintings to reconstruct the Gettysburg battlefield. The researchers were able to explain what Robert E. Lee could and could not see from his vantage points at the Lutheran seminary and on Seminary Hill. He probably could not see the Union forces amassing on the eastern side of the battlefield, which helps explain some of his tactical decisions, Knowles said.

Geoff Cunfer at the University of Saskatchewan studied a trove of data from all 208 affected counties in Texas, New Mexico, Colorado, Oklahoma and Kansas — annual precipitation reports, wind direction, agricultural censuses and other data that would have been impossible to sift through without the help of a computer. He learned dust storms were common throughout the 19th century, and that areas that saw nary a tiller blade suffered just as much.

The new data-mapping phenomenon is known as spatial humanities, the Times reports. Check out their story to find out how advanced technology is the future of history.

Computational chemistry shows the way to safer biofuels

Replacing gasoline and diesel with plant-based bio fuels is crucial to curb climate change. But there are several ways to transform crops to fuel, and some of the methods result in bio fuels that are harmful to health as well as nature.

Now a study from the University of Copenhagen shows that it is possible to predict just how toxic the fuel will become without producing a single drop. This promises cheaper, faster and above all safer development of alternatives to fossil fuel.

Solvejg Jorgensen is a computational chemist at the Department of Chemistry in Copenhagen. Accounts of her new computational prediction tool are published in acclaimed scientific periodical The Journal of Physical Chemistry A.

Among other things the calculations of the computer chemist show that bio fuels produced by the wrong synthesis path will decompose to compounds such as health hazardous smog, carcinogenic particles and toxic formaldehyde. Previously an assessment of the environmental impact of a given method of production could not be carried out until the fuel had actually been made. Now Jorgensen has shown that various production methods can be tested on the computer. This will almost certainly result in cheaper and safer development of bio fuels.

"There is an almost infinite number of different ways to get to these fuels. We can show the least hazardous avenues to follow and we can do that with a series of calculations that take only days", explains Jorgensen.

Chemically bio fuel is composed of extremely large molecules. As they degrade during combustion and afterwards in the atmosphere they peel of several different compounds. This was no big surprise. That some compounds are more toxic than others did not come as a revelation either but Jorgensen was astonished to learn from her calculations that there is a huge difference in toxicity depending on how the molecules were assembled during production. She was also more than a little pleased that she could calculate very precisely the degradation mechanisms for a bio fuel molecule and do it fast.

"In order to find the best production method a chemist might have to test thousands of different types of synthesis. They just can't wait for a method that takes months to predict the degradation mechanisms", explains Jorgensen who continues: "On the other hand: For a chemist who might spend as much as a year trying to get the synthesis right it would be a disaster if their method leads to a toxic result".

It seems an obvious mission to develop a computational tool that could save thousands of hours in the lab. But Solvejg Jorgensen wasn't really all that interested in bio fuels. What she really wanted to do was to improve existing theoretical models for the degradation of large molecules in the atmosphere.

To this end she needed some physical analysis to compare to her calculations. Colleagues at the Department of Chemistry had just completed the analysis of two bio fuels. One of these would do nicely. But Jorgensen made a mistake. And instead of adding just another piece to a huge puzzle she had laid the foundation for a brand new method.

"I accidentally based my calculations on the wrong molecule, so I had to start over with the right one. This meant I had two different calculations to compare. These should have been almost identical but they were worlds apart. That's when I knew I was on to something important", says Solvejg Jorgensen, who has utilised her intimate knowledge of the theoretical tool density functional theory and the considerable computing power of the University of Copenhagen.

Provided by University of Copenhagen

How to make solar power 24/7

Diagram shows the idealized arrangement of a vat of molten salt used to store solar heat, located at the base of a gently-sloping hillside that could be covered with an array of steerable mirrors all guided to focus sunlight down onto the vat. Image: Courtesy of Alexander Slocum et al.

The biggest hurdle to widespread implementation of solar power is the fact that the sun doesn't shine constantly in any given place, so backup power systems are needed for nights and cloudy days. But a novel system designed by researchers at MIT could finally overcome that problem, delivering steady power 24/7.

The basic concept is one that has been the subject of much research: using a large array of mirrors to focus sunlight on a central tower. This approach delivers high temperatures to heat a substance such as molten salt, which could then heat water and turn a generating turbine. But such tower-based concentrated solar power (CSP) systems require expensive pumps and plumbing to transport molten salt and transfer heat, making them difficult to successfully commercialize — and they generally only work when the sun is shining.

Instead, Alexander Slocum and a team of researchers at MIT have created a system that combines heating and storage in a single tank, which would be mounted on the ground instead of in a tower. The heavily insulated tank would admit concentrated sunlight through a narrow opening at its top, and would feature a movable horizontal plate to separate the heated salt on top from the colder salt below. (Salts are generally used in such systems because of their high capacity for absorbing heat and their wide range of useful operating temperatures.) As the salt heated over the course of a sunny day, this barrier would gradually move lower in the tank, accommodating the increasing volume of hot salt. Water circulating around the tank would get heated by the salt, turning to steam to drive aturbine whenever the power is needed.

The plan, detailed in a paper published in the journal Solar Energy, would use an array of mirrors spread across a hillside, aimed to focus sunlight on the top of the tank of salt below. The system could be "cheap, with a minimum number of parts," says Slocum, the Pappalardo Professor of Mechanical Engineering at MIT and lead author of the paper. Reflecting the system's 24/7 power capability, it is called CSPonD (for Concentrated Solar Power on Demand).

The new system could also be more durable than existing CSP systems whose heat-absorbing receivers cool down at night or on cloudy days. "It's the swings in temperature that cause [metal] fatigue and failure," Slocum says. The traditional way to address temperature swings, he says: "You have to way oversize" the system's components. "That adds cost and reduces efficiency." 

The team analyzed two potential sites for CSPonD on hillsides near White Sands, N.M., and China Lake, Calif. By beaming concentrated sunlight toward large tanks of sodium-potassium nitrate salt — each measuring 25 meters across and five meters deep — two installations could each provide 20 megawatts of electricity 24/7, which is enough to supply about 20,000 homes. The systems could store enough heat, accumulated over 10 sunny days, to continue generating power through one full cloudy day.

While exact costs are difficult to estimate at this early stage of research, an analysis using standard software developed by the U.S. Department of Energy suggests costs between seven and 33 cents per kilowatt-hour. At the lower end, that rate could be competitive with conventional power sources.

The team has carried out small-scale tests of CSPonD's performance, but its members say larger tests will be needed to refine the engineering design for a full-scale powerplant. They hope to produce a 20- to 100-kilowatt demonstration system to test the performance of their tank, which in operation would reach temperatures in excess of 500 degrees Celsius.

The biggest challenge, Slocum says, is that "it's going to take a company with long-term vision to say, 'Let's try something really different and fundamentally simple that really could make a difference.'"

Most of the individual elements of the proposed system — with the exception of mirror arrays positioned on hillsides — have been suggested or tested before, Slocum says. What this team has done is essentially an "assemblage and simplification of known elements," Slocum says. "We did not have to invent any new physics, and we're not using anything that's not already proven" in other applications.

Gershon Grossman, who holds the Sherman-Gilbert Chair in Energy at the Technion-Israel Institute of Technology, says this approach "includes several innovative CSP concepts." But, he adds, "the main advantage of this system is its ability to deliver power continuously, unlike other CSP systems, which are affected by clouds. This work is innovative and is expected to make a significant contribution" to the industry, he says.

Slocum emphasizes that this approach is not intended to replace other ways of harvesting solar energy, but rather to provide another alternative that may be best in certain situations and locations. Playing on the familiar saying about rising tides, he adds, "A rising sun can illuminate all energy harvesters."

New Fluorescent 'Spinach' Molecule Illuminates Inner Workings of RNA

Greens are good for you

By Rebecca Boyle

Spinach RNA Images of Spinach RNA expressed in E. coli. Colonies expressing the control molecule exhibited no fluorescence, but colonies expressing the Spinach molecule were brightly fluorescent. Paige et. al/© Science/AAAS

The newest optical techniques are making cell biology a little clearer, but it’s still a murky business, watching cells work. A new technique that illuminates RNA — the builder of proteins, making copies according to DNA’s blueprint — is one way to shine a light on that process.

Researchers have been using green fluorescent protein for years, tagging molecules and cells to make them glow under certain conditions and when certain changes occur. Now scientists at Weill Cornell Medical School in New York have figured out how to make RNA molecules light up, so they can watch them at work.

Monitoring RNA could help biologists understand how and when the molecules move around in cells, in response to which signals. This could help answer questions about gene expression and about viruses, which use RNA instead of DNA as their genetic material.

Jeremy Paige and colleagues at Weill Cornell worked with derivatives of the green fluorescent protein molecule, called fluorophores, which are what make the molecule glow in certain light wavelengths. They looked for short RNA molecules that could bind to them, the team explains in a paper published today in Science.

They found a host of combinations across the visible spectrum, but just like with jellyfish protein, green was the best. A combination of RNA and fluorophore complexes nicknamed Spinach is just as bright as GFP, the researchers say. What’s more, it doesn’t bleach under microscopic light, and it makes molecules glow faster than regular GFP. They tested it with E. coli and watched bacterial colonies light up.

The method could be a simpler way to tag RNAs for a wide range of applications, the researchers say.

Green Fluorescent RNA: Control E. coli is on the top left, and E. coli with RNA-fluorophore complex at bottom left.  Paige et. al/© Science/AAAS

Tiny Battery Embedded In a Nanowire Is the Smallest Battery Yet

By Rebecca Boyle

Nanowire Nanobattery Hybrid electrochemical energy storage devices combine the advantages of battery and supercapacitors, resulting in systems of high energy and power density. ACS Nano Letters

Nanotechnology promises to enable tiny, intricate circuits powering devices on any surface. But unless they’re harvesting energy from something like a heartbeat, the devices can only be as small as the smallest battery.

Now researchers at Rice University have combined the two, packing an entire lithium-ion battery into a single nanowire. The developers say it’s as small as such a device can possibly get.

Researchers led by Rice professor Pulickel Ajayan built a hybrid energy storage device, which serves as a battery and a supercapacitor. The first version sandwiched an electrolyte between a nickel/tin anode and a cathode made of a polymer called polyaniline. The cathode also served as a supercapacitor, storing lithium ions in bulk, as thiswriteup by Rice University explains. The prototype proved that lithium ions would move through the electrolyte and into the cathode.

Then Ajayan and colleagues incorporated this structure into a single nanowire, through a complicated process of etching and chemical washing. The goal is to make nanowires with ultra-thin separation between electrodes, so the device can remain as small as possible.

The completed wire-batteries are about 50 microns tall, which is roughly the diameter of a human hair, according to Rice.

For now, they can only charge and discharge about 20 times before they die, but researchers are trying to optimize them to last longer. The research is published in the journal ACS Nano Letters.