Changing the fate of stem cells

Researchers at the Wyss Institute for Biologically Inspired Engineering at Harvard Univ. and the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a new, more precise way to synthetically control differentiation of stem cells into bone cells by leveraging bioinspired hydrogels. This new technique has promising applications in the realm of bone regeneration, growth and healing. The research led by David Mooney, PhD, Wyss Institute Core Faculty member and Robert P. Pinkas Family Professor of Bioengineering at SEAS, was published in Nature Materials.

The extracellular matrix, a microenvironment of proteins and polymers that surrounds and connects cells, impacts a range of cellular behaviors including differentiation. For about a decade, researchers have been able to direct the fate of stem cells by tuning the mechanical stiffness of synthetic microenvironments such as hydrogels. Stem cells in more flexible hydrogels have been shown to differentiate into fat cells while those in stiffer hydrogels are more likely to differentiate into osteogenic (bone) cells.

Jaguar Land Rover Introduces Holographic Head-up Display

In 1988, General Motors brought the first head-up display (HUD) to market. Designed with the intent to keep driver attention on the road, these systems display vital information, such as vehicle speed and warning messages, in the driver’s field of vision.

Today, this technology is widely available, but the Univ. of Cambridge and Jaguar have teamed up to offer the first HUD to use laser holographic techniques to project information.

“We’re moving towards a fully immersive driver experience in cars, and we think holographic technology could be a big part of that, by providing important information, or even by encouraging good driver behavior,” said Prof. Daping Chu, of the university’s Dept. of Engineering and the Chairman of the Centre for Advanced Photonics and Electronics (CAPE).

Living Ant Bridges Have Implications for Robotics

Imagine this scenario: An earthquake strikes, collapsing the ends of a crowded bridge. People are stranded on the bridge’s interior, the gap to land being too big to jump. Emergency crews dispatch, but discover upon arrival that any sort of human intervention borders on fatal. Instead, the crews send out an array of insect-like robots. The robots coalesce, forming a platform where the gap once was. The trapped people cross safely to land.

While the above scenario is hypothetical, researchers have discovered army ants, known for building living bridges by linking their bodies, are capable of moving their bridges from the original building points to cover larger swaths.

Microscopic Water Bears Incorporate Foreign DNA into Genome

From the peaks of the Himalayas and the ocean’s deepest depths to frigid Antarctica and the searing deserts, tardigrades are animals that thrive in extremes.

Dry them out, and tardigrades can survive for years, even decades. Add water, and they spring back to life, raring to reproduce, feed and live their normal lives. Radiation? Not a problem, these microscopic animals can survive doses thousands of times more intense than humans can. The vacuum of space? Yeah, they survived that too.

“These abilities to survive these extreme stresses is what really got me interested in studying tardigrades,” says Thomas Boothby, a postdoctoral fellow at the Univ. of North Carolina at Chapel Hill, in an interview with R&D Magazine.  

Boothby and Bob Goldstein, a faculty member of UNC’s College of Arts and Sciences, recently sequenced the genome of these microscopic cosmopolitans. Surprisingly, the discovered 17.5% of their genome, around 6,000 genes, are from foreign DNA.

Launching into the Aurora Borealis

A psychedelic array, the aurora borealis are shimmering lights resulting from electrons form the sun colliding with particles in the Earth’s atmosphere. Against an ocean of stars, the phenomenon almost appears as cloudy drops of paint dispersing through water.

NASA, this winter, will launch two sounding rockets through the Northern Lights in Norway to study what is known as a cusp aurora, when “energetic particles are accelerated downward into the atmosphere directly from the solar wind—that is, the constant outward flow of solar material from the sun,” according to NASA. Cusp auroras, though not rare, pose a problem for visibility, as they often occur during daylight hours.

However, “the magnetic pole is tilted towards North America, putting this magnetic opening—the cusp—at a higher latitude on the European side,” said Jim LaBelle, principal investigator of the CAPER (Cusp Alfven and Plasma Electrodynamics Rocket) sounding rocket, one of the two rockets slated for launch. “Combine that extra-high latitude with the winter solstice—when nights are longest, especially as you go farther north—and you can sometimes see this daytime aurora with the naked eye.”

Tiny, ultracool star is super stormy

Our sun is a relatively quiet star that only occasionally releases solar flares or blasts of energetic particles that threaten satellites and power grids. You might think that smaller, cooler stars would be even more sedate. However, astronomers have now identified a tiny star with a monstrous temper. It shows evidence of much stronger flares than anything our sun produces. If similar stars prove to be just as stormy, then potentially habitable planets orbiting them are likely to be much less hospitable than previously thought.

"If we lived around a star like this one, we wouldn't have any satellite communications. In fact, it might be extremely difficult for life to evolve at all in such a stormy environment," says lead author Peter Williams of the Harvard-Smithsonian Center for Astrophysics (CfA).

An eagle-eye, real-time view of neural activity

Researchers at Duke and Stanford Univs. have devised a way to watch the details of neurons at work, pretty much in real time.

Every second of every day, the 100 billion neurons in your brain are capable of firing off a burst of electricity called an action potential up to 100 times per second. For neurologists trying to study how this overwhelming amount of activity across an entire brain translates into specific thoughts and behaviors, they need a faster way to watch.

Existing techniques for monitoring neurons are too slow or too tightly focused to generate a holistic view. But in a new study, researchers reveal a technique for watching the brain's neurons in action with a time resolution of about 0.2 usec—a speed just fast enough to capture the action potentials in mammalian brains.

The paper appeared early online in Science.

"We set out to combine a protein that can quickly sense neural voltage potentials with another protein that can amplify its signal output," said Yiyang Gong, assistant professor of biomedical engineering at Duke and first author on the paper. "The resulting increase in sensor speed matches what is needed to read out electrical spikes in the brains of live animals."

A new way to make x-rays

The most widely used technology for producing x-rays—used in everything from medical and dental imaging, to testing for cracks in industrial materials—has remained essentially the same for more than a century. But based on a new analysis by researchers at Massachusetts Institute of Technology (MIT), that might potentially change in the next few years.

The finding, based on a new theory backed by exact simulations, shows that a sheet of graphene—a 2-D form of pure carbon—could be used to generate surface waves called plasmons when the sheet is struck by photons from a laser beam. These plasmons in turn could be triggered to generate a sharp pulse of radiation, tuned to wavelengths anywhere from infrared light to x-rays.

Doping powers new thermoelectric material

In the production of power, nearly two-thirds of energy input from fossil fuels is lost as waste heat. Industry is hungry for materials that can convert this heat to useful electricity, but a good thermoelectric material is hard to find.

Increasing the efficiency of thermoelectric materials is essential if they are to be used commercially. Northwestern Univ. researchers now report that doping tin selenide with sodium boosts its performance as a thermoelectric material, pushing it toward usefulness. The doped material produces a significantly greater amount of electricity than the undoped material, given the same amount of heat input.

Details of the sodium-doped tin selenide—the most efficient thermoelectric material to date at producing electricity from waste heat—were published in Science.

The Northwestern development could lead to new thermoelectric devices with potential applications in the automobile industry, glass- and brick-making factories, refineries, coal- and gas-fired power plants, and places where large combustion engines operate continuously (such as in large ships and tankers).

Most semiconducting materials, such as silicon, have only one conduction band to work with for doping, but tin selenide is unusual and has multiple bands; the researchers took advantage of these bands. They showed they could use sodium to access these channels and send electrons quickly through the material, driving up the heat conversion efficiency.

"The secret to our material is that multiband doping produces enhanced electrical properties," said Mercouri G. Kanatzidis, an inorganic chemist who led the multidisciplinary team. "By doping multiple bands, we are able to multiply the positive effect. To increase the efficiency, we need the electrons to be as mobile as possible. Tin selenide provides us with a superhighway—it has at least four fast-moving lanes for hole carriers instead of one congested lane."

Kanatzidis, a Charles E. and Emma H. Morrison Professor of Chemistry in the Weinberg College of Arts and Sciences, is a world leader in thermoelectric materials research. He is a corresponding author of the paper.

To produce a voltage, a good thermoelectric material needs to maintain a hot side—where the waste heat is, for example—while the other side remains cool. (A voltage can be harvested as power.) Less than two years ago, Kanatzidis and his team, with postdoctoral fellow Lidong Zhao as protagonist, identified tin selenide as a surprisingly good thermoelectric material; it is a poor conductor of heat (much like wood)—a desirable property for a thermoelectric—while maintaining good electrical conductivity.

Kanatzidis' colleague Christopher M. Wolverton, a computational theorist, calculated the electronic structure of tin selenide. He found the electrical properties could be improved by adding a doping material.

"Tin selenide is very unusual, not only because of its exceedingly low thermal conductivity, but also because it has many conduction lanes," said Wolverton, a senior author of the paper and professor of materials science and engineering in the McCormick School of Engineering and Applied Science. "Our calculations said if the material could be doped, its thermal power and electrical conductivity would increase. But we didn't know what to use as a dopant."

Sodium was the first dopant the researchers tried, and it produced the results they were looking for. "Chris' computations opened our eyes to doping," Kanatzidis said. He and Zhao successfully grew crystals of the new doped material.

The researchers also were pleased to see that adding sodium did not affect the already very low thermal conductivity of the material. It stayed low, so the heat stays on one side of the thermoelectric material. Electrons like to be in a low-energy state, so they move from the hot (high-energy) side to the cool side. The hot side becomes positive, and the cool side becomes negative, creating a voltage.

"Previously, there was no obvious path for finding improved thermoelectrics," Wolverton said. "Now we have discovered a few useful knobs to turn as we develop new materials."

The efficiency of waste heat conversion in thermoelectrics is reflected by its "figure of merit," called ZT. In April 2014, the researchers reported that tin selenide exhibits a ZT of 2.6 at around 650 C. That was the highest ZT to date—a world record. But the undoped material produced that record-high ZT only at that temperature. (There is a ZT for every temperature.)

The new doped material produces high ZTs across a broad temperature range, from room temperature to 500 C. Thus, the average ZT of the doped material is much higher, resulting in higher conversion efficiency.

Supercomputers Help Model Gas Giants’ Storms

In 1664, jack-of-all-trades astronomer Giovanni Domenico Cassini set his telescope’s lens on Jupiter and observed the bands and spots of the planet. Later, in 1675, he discovered a narrow gap separating Saturn’s rings into two parts. The gap was later named the Cassini Division. His discoveries were monumental, but added more mystery to the celestial bodies above.

“Since the pioneering telescope observations of (Cassini) in the mid-17th century, stargazers have wondered about the bands and spots of Jupiter,” said Prof. Moritz Heimpel, who teaches physics at the Univ. of Alberta. “The average citizen can now pick up a backyard telescope and see the structures that we write about today. However, even in the present age with the Cassini spacecraft orbiting Saturn and the Juno craft approaching Jupiter, there is considerable debate about the dynamics of the atmosphere of the giant planets.”

With 3-D modeling from supercomputers and fluid dynamic equations, Heimpel and colleagues have simulated jet streams—the aforementioned bands—and storms—the aforementioned spots—of the two planets that caught Cassini’s explorative eyes.

The study was published in Nature Geoscience.

With Jupiter and Saturn, one huge question is just how deep the weather structures penetrate into the gas giants. “There’s no solid surface to stop them,” Heimpel said. “Our simulations imply that the jet streams plunge deep into the interior, while the storms are rather shallow.”

According to the researchers, storms on the planets can persist for centuries. Jupiter’s famous Great Red Spot, a giant anti-cyclonic storm, has been present for over 300 years of human observation.  

Favorable Launch Conditions for ISS Resupply Mission

Today, NASA announced a 60% chance of favorable launch conditions for the Orbital ATK Cygnus spacecraft aboard the Atlas V rocket, which is slated to carry more than 7,700 lbs of equipment, supplies and experiments to the International Space Station (ISS). The launch is scheduled for Thursday at 5:55 p.m. from NASA’s Kennedy Space Center in Florida.

“The primary concerns are cumulus clouds, disturbed weather and thick clouds at launch time,” according to NASA. “The rocket and spacecraft have a 30-min window to be able to launch and meet up with the (ISS) in orbit.”

According to the Orlando Sentinel, this is Orbital ATK’s first resupply mission to the ISS in over 13 months. The last one, on Oct. 28, 2014, blew up seconds after launch, destroying the Cygnus and supplies.

The new Cygnus, according to NASA, can carry 25% more mass than its predecessor. The payload includes The Space Automated Bioproduct Lab (SABL), a new life science facility capable of researching microorganisms, animal cells and tissues and small plant and animal organisms; the Packed Bed Reactor Experiment (PBRE), which will study the behavior of gases and liquids; a new jet pack called SAFER for astronauts to wear during spacewalks; and food, water and clothing, among other pieces of equipment.

Tech Tats: The Future of Wearables?

A forlorn girl sits at the bottom of a staircase in her household. An adult comes by with a small plastic case, opening it to reveal a rectangle sheet. The adult applies the sheet to the girl’s arm and holds a cloth over it. The cloth is pulled away and a small circuit board-like array with glowing green dots is stuck to the girl’s deltoid. The adult pulls out her smartphone, where the girl’s vitals are displayed.

“Rather than going to the doctor once a year to get your physical, this Tech Tattoo can be something that you just put on your body once a year and it monitors everything that they would do in a physical and sends that to your doctor, and if there’s an issue, they could call you,” said Eric Schneider, a creative technologist with Chaotic Moon, the developer of Tech Tats, in a video.

“It can look at early signs of fever, your vital signs, heartrate, everything that it needs to look at to notify you that you’re getting sick, or your child is getting sick.”

(Star’s Mysterious Dimming Likely Caused by Comets)

About one month ago, a group of scientists floated the idea that the dimming of star KIC 8462852 could be caused by an orbiting megastructure of alien origin. However, there were more promising, natural theories.

 Now, a new study using data from NASA’s Spitzer Space Telescope reinforces the theory the dimming is caused by a swarm of comets.

According to Iowa State Univ., the star undergoes deep dips in brightness, up to 22%, sometimes for days, even months, at a time. None of the other 150,000 plus stars in Kepler’s database exhibit similar characteristics. The original Yale Univ. study was based on Kepler observations from 2011 and 2013.

(Scientists Observe Hungry Black Hole Eating Stars)

In a galaxy 300 million light-years away, a star, roughly the size of the sun, felt the overwhelming gravitational pull of a supermassive black hole. It was sucked in, swallowed by the void, before being ejected as jets of matter, traveling nearly the speed of light.

“These events are extremely rare,” said Sjoert van Velzen, a Hubble fellow at Johns Hopkins Univ. “It’s the first time we see everything from the stellar destruction followed by the launch of a conical outflow, also called a jet, and we watched it unfold over several months.”

In December 2014, a research team from Ohio Stat Univ. announced the first observations of the star being destroyed on Twitter. The post was based on observations the team made with an optical telescope in Hawaii. Seeing the post, van Velzen enlisted the aid of an astrophysics team led by Rob Fender, of the Univ. of Oxford. The team gathered X-ray, radio and optical signals from the event by using satellites and ground-based telescopes.