German engineers bring us closer to air taxis that’ll zip passengers between cities, British researchers replace E. coli’s genome with a synthetic alternative, and Chinese researchers design a “glue” that can quickly stanch arterial bleeding. All these shiny new advances — plus one of the oldest trees in the world — in this week’s coolest scientific discoveries.
What is it? The German company Lilium has been developing a battery-powered plane that will act as a kind of high-speed air taxi, and this year the dream is really taking off — vertically, which is also how it lands. The company just released a video of a five-seat prototype lifting itself like a helicopter from a runway and hovering briefly above the ground before gently resettling.
Why does it matter? “This is the first time we have a full-scale, full-weight prototype of that five-seater version,” said Lilium co-founder Matthias Meiner. The brief liftoff was a small step but an important one, and the company will now continue to develop its technology while aiming for a “fully operational flying taxi service in multiple cities by 2025,” according to Andrew J. Hawkins in The Verge.
How does it work? One of the biggest technological challenges of electric flight, Hawkins continues, is the “power-to-weight ratio”: In terms of how much weight it adds, jet fuel gives a lot more bang for the buck than most current batteries. Without divulging the details, Lilium has expressed confidence that it can crack this nut; the company promises a vehicle with a top range of 186 miles, and a top speed of 186 mph. Its wings are fitted with 36 electric jet engines “that tilt up for vertical takeoff and then shift forward for horizontal flight,” and the craft is able to achieve relatively breezy speeds thanks to its fixed-wing design.
Top image credit: Lilium.
What is it? In the U.K., scientists at the Medical Research Council’s Laboratory of Molecular Biology have synthesized the entire genome of E. coli, essentially rewriting the bacterium’s genetic code. This is only the second time such a feat has been accomplished, and the new synthetic genome is about four times larger than the previous attempt.
Why does it matter? The ability to synthesize DNA might have novel medical uses some day — for instance, scientists might be able to recode DNA to be resistant to viral infection. More broadly, by re-creating the basic conditions by which organisms develop, researchers are attempting to gain a better understanding of how just four bases of DNA can give rise to all known life. As Carl Zimmer explains in the New York Times, one particular mystery the London researchers focused on was this: “Genes direct cells to choose among 20 amino acids, the building blocks of proteins, the workhorses of every cell.” They give this direction by way of codons, sequences of three DNA or RNA nucleotides that correspond to each of the 20 amino acids. But rather than there being just 20 codons in the genome, there are 64: Sixty-one to encode the amino acids, and three more to tell the DNA to stop building. What’s with the redundancy?
How does it work? Using computers, research leader Jason Chin and his team created a modified E. coli genome with 61 codons rather than 64. “In effect,” Zimmer writes, “the researchers treated E. coli DNA as if it were a gigantic text file, performing a search-and-replace function at over 18,000 spots.” They swapped the synthetic pieces into a real E. coli organism bit by bit until they’d replaced the bacterium’s entire genome. The bacteria remained — in a word — aliiiiiive, although “unusually shaped and reproducing slowly,” Zimmer writes. “But their cells operate according to a new set of biological rules, producing familiar proteins with a reconstructed genetic code.”
What is it? 2,624 years wasn’t just the running time of the last James Cameron movie. (Hey-o!) It’s also the age of a bald cypress tree recently discovered along the Black River in North Carolina — the oldest documented wetland tree species in the world, and fifth-oldest known tree in the world.
Why does it matter? University of Arkansas geoscience professor David Stahle has been studying trees in the area since 1985 and writes in Environmental Research Communications that living trees older than 2,000 years are “extremely rare worldwide. Only eight species have been proven with dendrochronology — the science of studying the age of things by analyzing tree rings and other signs of annual growth — to live for more than 2,000 years.” Until the bald cypress, none lived in the eastern U.S.
How does it work? Older than Christianity, the tree’s rings are able to tell a story of the past, particularly with respect to historical climate patterns. The bald cypress species is particularly good at retaining information about rainfall and moisture. “It’s an amazing coincidence that the oldest known living trees in eastern North America also have the strongest climate signal ever detected anywhere on Earth,” Stahle told the Smithsonian. A tree expert not associated with Stahle’s work, meanwhile, called bald cypress “a gold mine of climate information from the Southeast.”
What is it? A team of researchers from several Chinese institutions have created a hydrogel that can stop the bleeding from a punctured artery, according to a paper published in Nature Communications.
Why does it matter? As is well known, uncontrolled bleeding — such as in patients suffering from hemophilia — can be a life-threatening affliction, and scientists have been trying to devise a kind of “glue” that can be used in emergency situations to stem wounds. They haven’t managed to either due to the toxicity of materials they’ve experimented with, or because the glues have been too weak to stick to already wet tissue and stanch the flow of blood.
How does it work? The Chinese team combined water, gelatin, and a mix of proteins and chemicals into a gel they designed to resemble human connective tissue as closely as possible; the substance thickens and solidifies when exposed to ultraviolet light, preventing the flow of blood in as little as 20 to 30 seconds. The team reported that it could stand up to blood pressures of 290 mm Hg, “significantly higher than blood pressures in most clinical settings.” They continued, “Most importantly, the hydrogel can stop high-pressure bleeding from pig carotid arteries with 4~ 5 mm-long incision wounds and from pig hearts with 6 mm diameter cardiac penetration holes.”
What is it? Metal-organic frameworks, or MOFs — “self-assembling 3D compounds made of metallic and organic atoms connected together” — are promising materials that, some people think, could be to the 21st century what plastics were to the 20th. Recently, researchers at the University of Cambridge used machine learning to predict the mechanical properties of 3,000 MOFS, plus more MOFs that haven’t even been synthesized yet — perhaps speeding along their development.
Why does it matter? MOFs are porous, superversatile and highly customizable, and could have all sorts of uses: for instance, to “extract water from the air in the desert, store dangerous gases or power hydrogen-based cars,” according to a release from Cambridge. “That MOFs are so porous makes them highly adaptable for all kinds of different applications, but at the same time their porous nature makes them highly fragile,” said David Fairen-Jimenez, who led the research. Because of this fragility, many MOFs are often destroyed in the manufacturing process — the problem Fairen-Jimenez and colleagues set out to solve when programming their computers to predict the materials’ properties. They described the research in Matter.
How does it work? Understanding those properties will help manufacturers select only the MOFs “with the necessary mechanical stability” for production, according to Cambridge: “The researchers used a multi-level computational approach in order to build an interactive map of the structural and mechanical landscape of MOFs. First, they used high-throughput molecular simulations for 3,385 MOFs. Secondly, they developed a freely-available machine learning algorithm to automatically predict the mechanical properties of existing and yet-to-be-synthesized MOFs.” Did you get all that? It was a bit of a MOF-ful.