Another “impossible” crystal has been found locked inside a Russian meteorite.
The specimen is a quasicrystal, a type of material that shatters the rules of crystallography by having an ordered — yet never-repeating — arrangement of atoms. The new find is only the third natural quasicrystal ever found and is the first discovered in nature before being synthesized in a lab, researchers report online December 8 in Scientific Reports.
All three natural quasicrystals came from the same meteorite, discovered in a far-flung region of eastern Russia (SN: 11/3/12, p. 24). University of Florence geologist Luca Bindi and colleagues found micrometers-wide bits of the new quasicrystal in a grain of the meteorite collected during a 2011 expedition to the site. Probing the quasicrystal with electrons showed that the mineral is composed of aluminum, copper and iron atoms arranged in a way that’s similar to the pentagon-based pattern on a soccer ball.
Like its siblings, the new quasicrystal formed before landing on Earth when a cosmic fender bender between two space rocks caused rapid melting and cooling under extreme pressures, the researchers propose. While natural quasicrystals remain rare, companies have tinkered with using lab-made versions in everything from electronics to frying pan coatings.
A quarter century after scientists proposed an idea that profoundly influenced the arc of Alzheimer’s research, they might finally find out whether they are correct. A new antibody drug called aducanumab appears to sweep the brain clean of sticky amyloid-beta protein. The drug may or may not become a breakthrough Alzheimer’s treatment — it’s too soon to say — but either way it will probably answer a key question: Have researchers been aiming at the right target?
According to the proposal, called the amyloid hypothesis, Alzheimer’s disease, estimated to affect more than 5 million people in the United States alone, is caused by abnormal buildup of A-beta protein in the brain. The buildup chokes vital brain areas and destroys nerve cells. Despite amassing much support in recent decades, the proposal hasn’t managed to shake off its detractors. Aducanumab offers a seemingly reliable and safe way to lower A-beta levels and thus test the amyloid hypothesis. Over the course of a year, aducanumab entered the brains of people with early Alzheimer’s disease and cleared out the A-beta, scientists reported in September in Nature (SN: 10/1/16, p. 6). The trial was small — only 165 people. Yet in these people’s brains, amyloid-beta clearly declined. The higher the dose, the more A-beta cleanup.
There were hints that people on higher doses of the drug had cognitive improvements, too. If confirmed in larger studies, those cognitive benefits “would be a game changer for the field,” says Alzheimer’s researcher Eric Reiman of the Banner Alzheimer’s Institute in Phoenix. But those results “need to be treated agnostically for now,” at least until the larger studies currently under way are completed, he cautions. There is already strong evidence that A-beta is a disease culprit: Rare genetic mutations in genes related to A-beta almost always come with Alzheimer’s, an observation that has been confirmed in mice. A-beta is toxic to nerve cells in dishes, damaging their communication abilities before eventually killing the cells outright. “All the basic science work and natural history work supports it,” says neuroscientist John Hardy of University College London, who is among those who proposed the amyloid hypothesis. Yet contradictions exist. Cognitively healthy people have been found with A-beta accumulation in their brain (SN: 12/10/16, p. 13). And so far, scientists have found only a weak correlation between A-beta plaques and cognition, results that have led some scientists to look elsewhere — to inflammation, overzealous pruning of brain cell connections called synapses and changes to the protein tau, which is known to accumulate inside nerve cells in people with Alzheimer’s. Each of these cellular processes has also been implicated as a driver of the disease.
Identifying the true cause of Alzheimer’s is difficult because all of these processes are closely related and occur simultaneously, making it nearly impossible to study their effects in isolation. What’s more, many of the key changes might happen years, or even decades, before symptoms begin to appear. Hardy concedes that in the years since he and others introduced the amyloid hypothesis, scientists have struggled to put together a full picture of Alzheimer’s. “It is tougher than we all thought it would be,” he says.
There won’t be clear answers for several years yet. In August of 2015, larger clinical trials of aducanumab began enrolling patients around the world with the goal of finishing by 2022. As more people with Alzheimer’s are tested, researchers hope to see obvious signs of mental improvement that track reductions in brain A-beta. It’s possible that aducanumab will lower A-beta in the brain yet fail to bring meaningful improvements in symptoms. Such a result might appear to be a strike against the amyloid hypothesis, a contradiction that could prod some researchers to explore other ideas more deeply. Either way, people with Alzheimer’s and their loved ones are waiting anxiously.
A chatty source of radio waves from deep space has a little more to say. Six more blasts of radio energy, each lasting just a few milliseconds, erupted from some phenomenon outside of our galaxy, researchers report in the Dec. 20 Astrophysical Journal. This detection follows 11 previously recorded outbursts of radio waves from the same location, the only known repeater in a class of enigmatic eruptions known as fast radio bursts.
The origins of these radio bursts, 18 of which have been reported since 2007, are an ongoing puzzle (SN: 8/9/14, p. 22). The continuing barrage from this repeating source, roughly 3 billion light-years away in the constellation Auriga, implies that whatever is causing some radio bursts is not a one-time destructive event such as a collision or explosion. Flares from a young neutron star, the dense core left behind after a massive star explodes, are a promising candidate.
The latest volley was detected in late 2015, Paul Scholz, a graduate student at McGill University in Montreal, and colleagues report. Five blasts were recorded at the Green Bank Telescope in West Virginia and one at Arecibo Observatory in Puerto Rico. This object was first detected at Arecibo in 2012. Ten more blasts followed in May and June 2015 (SN: 4/2/16, p. 12).
One of Antarctica’s largest ice shelves is nearing its breaking point, scientists warn. A colossal crack in the Larsen C ice shelf grew by 18 kilometers during the second half of December, members of the Antarctic research group Project MIDAS reported January 5. The crack is only about 20 kilometers away from reaching Larsen C’s edge and snapping off a Delaware-sized hunk of ice.
Such a breakup could destabilize the ice shelf — similar to the collapse of Larsen B in 2002, scientists with the project forecast in 2015 (SN: 7/25/15, p. 8). Because Larsen C’s ice is floating on the ocean, the breakup won’t directly raise sea levels. But with the ice shelf gone, more glacial ice could slip into the sea unabated and contribute to sea level rise.
Immune cells in a malaria-transmitting mosquito sense the invading parasites and deploy an army of tiny messengers in response. These couriers help turn on a mosquito’s defenses, killing off the parasites, a new study suggests.
This more detailed understanding of the mosquito immune system, published January 20 in Science Immunology, might help scientists design new ways to combat malaria, which infects more than 200 million people per year.
“If we understand how the mosquito reduces the parasite to begin with, we hope we can boost these mechanisms to completely eliminate these parasites [in mosquitoes],” says Kristin Michel, an insect immunologist at Kansas State University in Manhattan who wasn’t part of the study. Different parasites in the Plasmodium genus cause malaria. The disease is spread by certain Anopheles mosquitoes. These mosquitoes have natural defenses against Plasmodium that keep them from being overrun with the parasites when feeding on an infected person’s blood. But malaria transmission still occurs, because some Plasmodium species are particularly skilled at evading mosquito immune systems.
Previous research has shown that hemocytes, the insect equivalent of white blood cells, help mosquitoes fight off pathogens. Carolina Barillas-Mury and her colleagues at the National Institute of Allergy and Infectious Diseases in Rockville, Md., injected Anopheles gambiae mosquitoes — a primary spreader of malaria in sub-Saharan Africa — with a dye that stained their hemocytes. Those mosquitoes snacked on mice infected with a rodent version of malaria. Then the scientists watched the dyed hemocytes’ response. Hemocytes that detected certain chemical fingerprints left by the parasites began to self-destruct. These dying hemocytes released plumes of tiny vesicles that then activated the mosquito’s defenses against the parasite, the researchers found. The vesicles triggered a protein called TEP1 to take down the parasite. Scientists already knew that TEP1 is an important part of mosquitoes’ immune response against Plasmodium parasites, but it wasn’t clear how the protein was called into action. Without the vesicles, TEP1 didn’t target the parasites. Barillas-Mury and colleagues don’t know exactly what the microvesicles contain. But she suspects they carry messenger molecules that jump-start TEP1 and other proteins involved in this immune response.
This type of response “is a very powerful defense system because it can make holes in the parasite and kill it,” says Barillas-Mury. “You want it to be active, but in the right place and at the right time.” Plasmodium parasites set up shop in different places in the mosquito gut depending on their life stage. Microvesicles, much smaller than the hemocytes, can more easily move through different gut compartments to trigger a localized immune response right where the parasite is.
The researchers eventually hope to use their understanding of the mosquito immune response to develop new ways to stop malaria. They’re interested in creating a vaccine that prevents mosquitoes that bite an infected person from passing along the parasite. Such a vaccine could be used in combination with others under development that would prevent people infected with the parasite from becoming sick, Barillas-Mury says.
A strange X-ray signal has popped up again in new measurements, raising hopes that it could be a sign of dark matter.
Data from NASA’s Chandra X-ray Observatory reveal an excess of X-rays at a particular energy, creating a bump on a plot, scientists report online at arXiv.org on January 29. The X-ray “line,” as it is known, could reveal the presence of dark matter — an unknown substance that scientists believe constitutes most of the matter in the cosmos. While the X-ray line has been found previously using several different telescopes, some searches have come up empty (SN: 9/3/16, p. 17). The new observation strengthens the case that the odd feature is real, and eliminates some possible mundane explanations.
“This is a very exciting thing,” says astrophysicist Nico Cappelluti of Yale University, a coauthor of the report. “This is another measurement that sees the line in another direction.”
The new analysis uses data taken when the telescope was observing deep space, rather than pointing at a particular cluster of galaxies. So if the signal indicated dark matter, it would be due to particles in the region surrounding the Milky Way, known as its halo. When hypothetical dark matter particles called sterile neutrinos decay, they could produce X-rays at the energy of the line, about 3,500 electron volts (SN Online: 12/11/15).
Cappelluti and colleagues found that the relative intensity of the line in the halo and the line previously found at the center of the Milky Way was consistent with the expected variation in concentration of dark matter in various parts the galaxy.
Dark matter isn’t the only possible explanation — standard physics might also be able to explain the line. “There’s definitely a lot of debate,” says Shunsaku Horiuchi, an astroparticle physicist at Virginia Tech in Blacksburg who was not involved with the new work. The line “looks like it’s real, but then I don’t know if it’s dark matter or some atomic physics.” Although there’s still a small chance that the result could be a statistical fluke, the analysis eliminates some other possible explanations. Scientists had proposed that the line could be the result of sulfur ions grabbing an electron from hydrogen atoms in space, but that process couldn’t explain the new data, Cappelluti and colleagues concluded. Likewise, a quirk of the telescope itself couldn’t explain the line, they determined.
“It’s kind of getting other people excited,” says Horiuchi.
After flying more than 10,000 kilometers from South America to the Arctic, male pectoral sandpipers should be ready to rest their weary wings. But once the compact shorebirds arrive at a breeding ground in Barrow, Alaska, each spring, most keep going — an average of about 3,000 extra kilometers.
Scientists thought males, which mate with multiple females, stayed put at specific sites around the Arctic to breed. Instead, in a study of 120 male pectoral sandpipers in Barrow, most flitted all across the region looking for females. One bird flew a whopping 13,045 kilometers more after arriving, researchers report online January 9 in Nature. “We had no clue that they range over such a wide area,” says study coauthor Bart Kempenaers, a behavioral ecologist at the Max Planck Institute for Ornithology in Seewiesen, Germany. To track the birds, the researchers placed satellite transmitters on 60 males in 2012 and another 60 in 2014.
“It doesn’t seem to be very tough for them to do these flights,” Kempenaers says. Competition for a mate, however, is cutthroat. In Barrow, just a few males sire the majority of offspring each year. The new work shows males visited as many as 24 potential breeding sites over four weeks, perhaps to boost their chances of reproducing.
Some had better stamina than luck. Kempenaers told of one male’s 2,000-kilometer Arctic odyssey: Once the bird reached Barrow, it flew north over the Arctic Ocean before turning around and landing just 300 kilometers from where it started. “There’s nothing northwards. There is only the [North] Pole, no land,” he says.
A new scorecard, devised by analyzing Ebola patients from the most recent outbreak in West Africa, may help doctors quickly decide who needs additional care to survive the virus in future epidemics.
In the latest outbreak, which raged in Guinea, Liberia and Sierra Leone from 2014 to 2016, 28,616 people were infected with virus and 11,310 people died. Doctors might be able to improve the odds of surviving by looking for a few warning signs in people who need to be treated more intensively, Mary-Anne Hartley, of the international charity GOAL Global and the University of Lausanne in Switzerland, and colleagues report February 2 in PLOS Neglected Tropical Diseases. “It can be very difficult to avoid bias when choosing which Ebola patient should be given extra care when you have limited time and resources,” Hartley says. “Should it be that sweet 7-year-old girl in the corner with a bad cough or the really athletic 45-year-old man who was a bit confused earlier? Our score suggests that it should be the latter.”
Top risk factors for dying from Ebola: High viral load — Patients with lots of virus in their blood were 12.6 times as likely to die as those with a low viral load. Age — Children under 5 were 5.4 times as likely to die as were people between 5 and 25; people over age 45 were 11.6 times as likely to die. Disorientation — The symptom was associated with more than 94 percent of Ebola fatalities and increased the risk of dying by 13.1 times. Hiccups Diarrhea Red, inflamed eyes Labored breathing or shortness of breath Muscle pain Delayed treatment — The risk of dying increased 12 percent each day an infected person put off treatment for the first 10 days after symptoms started.
Astronomers may have spotted some of the earliest stardust ever created in the cosmos.
Astrophysicist Nicolas Laporte of University College London and colleagues detected the dust in a galaxy seen as it was when the universe was only 600 million years old. “We are probably seeing the first stardust of the universe,” Laporte says. The observations, published online March 8 in the Astrophysical Journal Letters, could help astronomers learn more about an early period known as cosmic reionization, when ultraviolet radiation stripped electrons from hydrogen atoms. “Dust is ubiquitous in nearby and more distant galaxies, but has, until recently, been very difficult to detect in the very early universe,” says University of Edinburgh astrophysicist Michal Michalowski, who was not involved in the study. “This paper presents the most distant galaxy for which dust has been detected.”
The galaxy, called A2744_YD4, lies behind a galaxy cluster called Abell 2744. That cluster acts as a gravitational lens, magnifying and brightening the distant galaxy’s light by about a factor of two. Laporte and colleagues observed the galaxy with ALMA, the Atacama Large Millimeter/submillimeter Array in Chile, which revealed the dust. Dust in such a remote galaxy comes from supernova explosions of massive stars that were among the earliest stars in the universe. Astronomers estimate the first stars formed around 400 million years after the Big Bang, which occurred 13.8 billion years ago. Laporte and colleagues estimate that A2744_YD4’s dust, at 600 million years after the Big Bang, weighs in at about 6 million times the mass of the sun. “This means that supernova explosions are able to produce large amounts of dust very quickly,” Michalowski says. Laporte and colleagues also detected positively charged, or ionized, oxygen atoms and a signature of hydrogen, which suggest the galaxy’s gas is ionized. Cosmic reionization completely rebooted the universe so that ionized rather than neutral atoms pervaded space. Understanding this switch from neutral to ionized atoms gives clues to how stars and galaxies arose in the early universe. Finding ionized oxygen in such a remote galaxy “provides evidence that at least a fraction of cosmic reionization was caused by galaxies like A2744_YD4,” Michalowski says.
Until now, astronomers have been charting the early history of galaxies by counting them and looking at their colors, notes study coauthor Richard Ellis, a cosmologist currently on leave from University College London at the European Southern Observatory. Spotting dust in the distant universe offers a new route to determine when the earliest galaxies first formed, based on the abundances of oxygen, silicon and other heavier elements that they contain. Fewer heavy elements would point to younger and younger galaxies.
The detection of ionized oxygen could also hint that a black hole lurks at the center of A2744_YD4. Ionized oxygen, seen by the signal it emits in millimeter wavelengths, may be difficult to generate from young hot stars alone. Another strong source of ionizing radiation, such as a black hole, may be needed to account for the signature. “Unfortunately with only one emission line we cannot, for sure, claim there’s a black hole in A2744_YD4,” Ellis says.
Sea ice skylights formed by warming Arctic temperatures increasingly allow enough sunlight into the waters below to spur phytoplankton blooms, new research suggests. Such conditions, probably a rarity more than two decades ago, now extend to roughly 30 percent of the ice-covered Arctic Ocean during July, researchers report March 29 in Science Advances.
The microscopic critters need plenty of sunlight to thrive, so scientists were stunned by the discovery of a sprawling bloom below the normally sun-blocking Arctic ice in July 2011 (SN: 7/28/12, p. 17). Satellites can’t peek below the ice, though, so scientists at the time didn’t know whether the bloom was an oddity or representative of a shift in the Arctic environment.
Harvard University oceanographer Christopher Horvat and colleagues created a computer simulation of sea ice conditions from 1986 through 2015. Warming temperatures have thinned the ice, the researchers found, and increased the prevalence of meltwater pools on top of the ice that allow more light to pass through than bare or snow-covered ice.
Whether blooms are in fact more commonplace under the ice remains unclear, though, because the study didn’t consider whether there would be enough nutrients such as nitrogen and iron for budding blooms. If more blooms are lurking in the Arctic Ocean, they may already be dramatically reshaping the Arctic ecosystem. A boost in phytoplankton could alter marine food webs as well as soak up more planet-warming carbon dioxide from the environment.
Big bloom Increasingly large swaths of the ice-covered Arctic Ocean allow enough light into the waters below to support phytoplankton blooms, new research suggests. Green regions indicate bloom-friendly conditions in July over the last few decades, with darker shades representing longer duration.
