Scanning the skies for near-earth asteroids might be the best first step for getting humans to Mars.
planetary scientist Richard Binzel argues that NASA should abandon the AsteroidRedirect Mission, the space agency’s plan to snag a space rock and jockey it into lunar orbit for astronauts to explore. Instead, NASA should beef up its telescope surveys to search for asteroids that come closer to home. At least one whizzes between the Earth and the moon every week, Binzel writes.
Sending humans out to these nearby asteroids would save scientists the trouble of wrangling a far-outspace rock, and it would giveastronauts a smorgasbord ofdifferent stepping stones to Mars, he notes.
Itty-bitty seeds of human stomachs can now bud in plastic dishes.
By bathing stem cells in a brew of growth-boosting chemicals, scientists have kick-started the constructionof crude organs about as bigas the head of a pin. These primitive balls of gastric tissue — the first to be cooked up in the lab — resemble the stomachs of developing fetuses. The lab-grown bellies represent the latest in a line of do-it-yourself organlike cell clumps, including livers, brains and guts
Three years after figuring outhow to transform stem cells into human intestinal tissue, and more recently, how to make that tissue grow in mice (SN Online: 10/19/14), developmental biologist James Wells of Cincinnati Children’s Hospital Medical Center and colleagues have monkeyed with their method to make 3-D stomachlike organs.
Like human stomachs, the lab-grown globs contain both mucus-making and hormone-pumping cells. Thetissue also mimics a stomach’s response to infection withHelicobacter pylori. The ulcer-causing bacteria cue the globs to switch on the same molecular signals that real stomach cells use, Wells andhis team reportOctober 29 inNature.
The mini stomachs hand researchers a new tool for studying gastric human disease, including cancer, the researchers suggest.
A tiny quail and a huge ostrich would seem to have little in common given their 500-fold difference in size. But when faced with an obstacle in their path, the birds tackle it in the same way, scientistsreportOctober 29 in theJournal of Experimental Biology.Aleksandra Birn-Jeffery of the Royal Veterinary College in Hatfield, England, and colleagues wanted to know how running birds negotiate a step. How two-legged creatures navigate obstaclescan be helpful for inventors hoping to create two-legged robots, but it seems that humans may not be the best models. Though our ancestors started walking uprightmillions of years ago, birds have been doing it for far longer — bipedal locomotion can be traced back 230 million years totheropoddinosaurs.So the researchers brought five species of birds into the lab: quail, pheasant, guinea fowl, North American turkey and ostrich. Because ostriches are capable of killing people (a common trait among manylarge flightless birds), Birn-Jeffery hand-raised the birds for twoyears so they could be safelyhandled. Members of the other species had their wings clipped so that they wouldn’t fly away.
The scientists presented each bird with a step sized appropriately to the bird’s height. Each bird ran over theobstacle, taking some practice runs so they could optimize their strategy. Then the researchers filmed the birds on their runs and measured the force of their steps.All the birds tackled the step in a similar way — in three steps, with an initial vault onto the step and slightly crouching while on top of it — regardless of size. This was surprising because the large ostrich runs differently than the smaller birds. The ostrich uses straighter legs to minimize stress on muscles and bones, while the smaller species tend to crouch, which allows for smooth body motion over uneven terrain. But when faced with a step, all the birds used a strategy that coupled energy efficiency with leg safety.“In the wild, injuries can result in predation, and food energy resources are often limited, thus, injury avoidance and economy are likely to be important factors in fitness,” the researchers note.The motion isn’t always smooth and sleek, though. The birds avoid falling and injuring themselves, but theirupper bodies may bounce around.The similarities between species may break down, however, with obstacles of a different size or type, Birn-Jeffery says. “A large bird, such as an ostrich, would not be able to successfully negotiate an 80-percent-leg-length obstacle using this strategy,”she says. “They would more than likely have to slow down before encountering the obstacle, something which none of our birds in the current study did.” A quail, though, might not haveto change its strategy to tackle a higher height.Coauthor Monica Daley, also at the Royal Veterinary College, is currently investigating whether the birds’ strategies change withother types of terrain. The research may help scientistscreate stable, running robots.Bipedal, ground-running birds come in a variety of sizes, from tiny quail to hugeostriches. But when presented with a short step, they all tackle the obstacle ina similar way: an initial vault up, slightly crouching on top and a third step back down to the ground.
A new frog species, discovered in New York City six years ago, has been found in many spots along the East Coast, from Connecticut to North Carolina.The Atlantic Coast leopard frog (Rana kauffeldi) wasfirstidentified on Staten Island when ecologists realized that its call was distinct fromthat of a lookalike, the southern leopard frog (Rana sphenocephala). The Atlantic Coast speciescroaks in a single burst of sound, while the southern leopard frog calls with multiple pulses.Researchers have now collected recordings of calls and tissue samples from leopard frogs along the East Coast to define the range of the new species. They found the Atlantic Coast leopard frog in coastal freshwater wetlands and low-lying river floodplains along a wide swath of the coast. The new frog’s rangeis described October 29 inPLOS ONE.“We can still find new species not only in the rainforest or in remote areas of the world, but in places that are very familiar,” says coauthor Jeremy Feinberg, an ecologist at Rutgers University in New Brunswick,N.J. “Your backyard might just have a surprise.”
NASA scientists have applied new super-black carbon-nanotube coating to a 3-D component critical for suppressing stray light in a new solar coronagraph.
An emerging super-black nanotechnology that is to be tested for the first time this fall on the International Space Station will be applied to a complex, 3-D component critical for suppressing stray light in a new, smaller, less-expensive solar coronagraph designed to ultimately fly on the orbiting outpost or as a hosted payload on a commercial satellite.
The super-black carbon-nanotube coating, whose development is six years in the making, is a thin, highly uniform coating of multi-walled nanotubes made of pure carbon about 10,000 times thinner than a strand of human hair. Recently delivered to the International Space Station for testing, the coating is considered especially promising as a technology to reduce stray light, which can overwhelm faint signals that sensitive detectors are supposed to retrieve.
While the coating undergoes testing to determine its robustness in space, a team at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, will apply the carbon-nanotube coating to a complex, cylindrically shaped baffle — a component that helps reduce stray light in telescopes.
Goddard optical engineer Qian Gong designed the baffle for a compact solar coronagraph that Principal Investigator Nat Gopalswamy is now developing. The goal is build a solar coronagraph that could deploy on the International Space Station or as a hosted payload on a commercial satellite — a much-needed capability that could guarantee the continuation of important space weather-related measurements.
The effort will help determine whether the carbon nanotubes are as effective as black paint, the current state-of-the-art technology, for absorbing stray light in complex space instruments and components.
Preventing errant light is an especially tricky challenge for Gopalswamy’s team. “We have to have the right optical system and the best baffles going,” said Doug Rabin, a Goddard heliophysicist who studies diffraction and stray light in coronagraphs.
The new compact coronagraph — designed to reduce the mass, volume, and cost of traditional coronagraphs by about 50 percent — will use a single set of lenses, rather than a conventional three-stage system, to image the solar corona, and more particularly, coronal mass ejections (CMEs). These powerful bursts of solar material erupt and hurdle across the solar system, sometimes colliding with Earth’s protective magnetosphere and posing significant hazards to spacecraft and astronauts.
“Compact coronagraphs make greater demands on controlling stray light and diffraction,” Rabin explained, adding that the corona is a million times fainter than the sun’s photosphere. Coating the baffle or occulter with the carbon-nanotube material should improve the component’s overall performance by preventing stray light from reaching the focal plane and contaminating measurements.
The project is well timed and much needed, Rabin added.
Currently, the heliophysics community receives coronagraphic measurements from the Solar and Heliospheric Observatory (SOHO) and the Solar Terrestrial Relations Observatory (STEREO).
“SOHO, which we launched in 1995, is one of our Great Observatories,” Rabin said. “But it won’t last forever.” Although somewhat newer, STEREO has operated in space since 2006. “If one of these systems fails, it will affect a lot of people inside and outside NASA, who study the sun and forecast space weather. Right now, we have no scheduled mission that will carry a solar coronagraph. We would like to get a compact coronagraph up there as soon as possible,” Rabin added.
Ground-based laboratory testing indicates it could be a good fit. Testing has proven that the coating absorbs 99.5 percent of the light in the ultraviolet and visible and 99.8 percent in the longer infrared bands due to the fact that the carbon atoms occupying the tiny nested tubes absorb the light and prevent it from reflecting off surfaces, said Goddard optics engineer John Hagopian, who is leading the technology’s advancement. Because only a tiny fraction of light reflects off the coating, the human eye and sensitive detectors see the material as black — in this case, extremely black.
“We’ve made great progress on the coating,” Hagopian said. “The fact the coatings have survived the trip to the space station already has raised the maturity of the technology to a level that qualifies them for flight use. In many ways the external exposure of the samples on the space station subjects them to a much harsher environment than components will ever see inside of an instrument.”
Given the need for a compact solar coronagraph, Hagopian said he’s especially excited about working with the instrument team. “This is an important instrument-development effort, and, of course, one that could showcase the effectiveness of our technology on 3-D parts,” he said, adding that the lion’s share of his work so far has concentrated on 2-D applications.
By teaming with Goddard technologist Vivek Dwivedi, Hagopian believes the baffle project now is within reach. Dwivedi is advancing a technique called atomic layer deposition (ALD) that lays down a catalyst layer necessary for carbon-nanotube growth on complex, 3-D parts. “Previous ALD chambers could only hold objects a few millimeters high, while the chamber Vivek has developed for us can accommodate objects 20 times bigger; a necessary step for baffles of this type,” Hagopian said.
Other NASA researchers have flown carbon nanotubes on the space station, but their samples were designed for structural applications, not stray-light suppression — a completely different use requiring that the material demonstrate greater absorption properties, Hagopian said.
“We have extreme stray light requirements. Let’s see how this turns out,” Rabin said.
A new power-conserving chip developed by MIT spinout Eta Devices may increase smartphone battery life and save energy in cell towers.
Stream video on your smartphone, or use its GPS for an hour or two, and you’ll probably see the battery drain significantly. As data rates climb and smartphones adopt more power-hungry features, battery life has become a concern. Now a technology developed by MIT spinout Eta Devices could help a phone’s battery last perhaps twice as long, and help to conserve energy in cell towers.
The primary culprit in smartphone battery drain is an inefficient power amplifier, a component that is designed to push the radio signal out through the phones’ antennas. Similar larger modules are found in wireless base stations, where they might use 10 or even 100 times the power.
Prepared to send sizeable chunks of data at any given time, the amplifiers stay at maximum voltage, eating away power — more than any other smartphone component, and about 75 percent of electricity consumption in base stations — and wasting more than half of that power as heat. This means smartphone batteries lose longevity, and base stations waste energy and lose money.
But Eta Devices has developed a chip (for smartphones) and a shoebox-size module (for base stations) — based on nearly a decade of MIT research — to essentially “switch gears” to adjust voltage supply to power amplifiers as needed, cutting the waste.
“You can look at our technology as a high-speed gearbox that, every few nanoseconds, modulates the amount of power that the power amplifier draws from the battery,” explains Joel Dawson, Eta Devices’ chief technology officer and a former associate professor of electrical engineering and computer science who co-invented the technology. “That turns out to be the key to keeping the efficiency very high.”
When trialed in a base station last year, Eta Devices’ module became the first transmitter for 4G LTE networks to achieve an average efficiency greater than 70 percent, Dawson says. “The highest number we’ve heard before that was 45 percent — and that’s probably being generous,” he says.
Backed by millions in funding, Eta Devices — co-founded by David Perreault, an MIT professor of electrical engineering, and former MIT Sloan fellow Mattias Astrom — has partnered with a large base-station manufacturer. The goal is to deploy the technology in live base stations by the end of 2015. The savings could be substantial, Dawson says, noting that a large carrier could save $100 million in annual electricity costs.
Eta Devices has also entered conversations with major manufacturers of LTE-enabled smartphones to incorporate their chips by the end of next year. Dawson says this could potentially double current smartphone battery life.
Besides battery life, Dawson adds, there are many ways the telecommunications industry can take advantage of improved efficiency. Eta Devices’ approach could lead to smaller handset batteries, for example, and even smaller handsets, since there would be less dissipating heat. The technology could also drive down operating costs for base stations in the developing world, where these stations rely on expensive diesel fuel for power.
And ultimately, it could impact the environment: If all midsized carrier networks were to replace current radio amplifiers with Eta Devices’ technology, he says, the reduction in greenhouse gases would be equivalent to taking about 5 million cars off the road. “There are so many ways to leverage high efficiency if you have it,” Dawson says.
In August, the World Economic Forum named Eta Devices the 2015 Technology Pioneer, a designation awarded previously to Dropbox, Spotify, and Twitter, to name a few.
In the mobile market
Eta Devices’ commercial success is, in part, a product of engineering ingenuity intersecting with business acumen at MIT.
In 2008, Dawson and Perreault, who directs the Power Electronics Research Group, submitted an early concept of the Eta technology — then called asymmetrical multilevel outphasing (AMO) — to an Innovation Teams (i-Teams) class that brought together MIT students from across disciplines to develop commercial products.
The AMO technology was a new transmitter architecture, where algorithms could choose from different voltages needed to transmit data in each power amplifier, and select the optimal choice for power conservation — and do so roughly 20 million times per second. This could be done on the transmitting and receiving end of data transfers.
This caught the eye of Astrom, who had come to MIT after working in the mobile industry for 10 years, “looking for the next big thing.” With help from Astrom, the professors started designing the technology for the mobile market — initially leaning toward base stations.
“At the time, I was suffering, as everyone else was, from my iPhone running out of battery at lunchtime,” Astrom says. “The iPhone was only a year old, but you could see how much data traffic would explode.”
Fleshing out a business plan from an i-Teams draft, the two professors earned a Deshpande Center for Technological Innovation grant in 2009, allowing for the first demonstration of the hardware, showing a 77 percent gain in efficiency over standard systems. (A paper detailing the technology was presented at that year’s IEEE Radio Frequency Integrated Circuits Symposium.)
“That Deshpande Center grant was big in terms of the funding and connecting us with local venture capitalists, and really helping with being in that business mindset,” Dawson says.
Eta Devices launched in 2010, with Astrom as its CEO. From there, it’s been all rapid prototyping at Eta Devices’ Cambridge and Stockholm offices, as well as gathering customer feedback.
Spinning out a company has been the best way to validate the technology — especially with novel power-electronics hardware, Dawson says. “People in our industry take ideas a lot more seriously when there’s a company behind it,” he says. “We had impressive performance at MIT, but now we have a team of professionals working on the technology full-time. The resulting performance numbers are jaw-dropping. Now people are going back and frantically studying the original MIT research papers.”
Luckily, Dawson says, several significant changes were made to those old research projects in order to develop today’s ETAdvanced — so the secret ingredients of the technology are safe. “The joke I like to tell is: When I was a professor, I was going around the world trying to give the technology away,” Dawson says, laughing. “If I had succeeded, then there’d be no business.”
Future-proofing technology
Today, Eta Devices’ major advantage is that its technology is able to handle ever-increasing data bandwidths.
A few major smartphone manufacturers are now using envelope tracking (ET), which adjusts voltage to power amplifiers on the fly. But by adjusting that voltage continuously, ET efficiency falls apart for 4G/LTE and 802.11ac (WiFi) wireless standards, even up to 20 MHz bandwidth. ETAdvanced, in contrast, already accommodates ultrahigh bandwidths used by newer communication standards, such as LTE Advanced (up to 80 megahertz), and the next-generation WiFi standard (up to 160 megahertz).
Prepping for future communication standards is one thing that’s helped the company thrive, Dawson says. “As a small company, you’ll lose a fair fight with another technology — you have to have some overpowering advantage that they can’t match you on,” he says. “In introducing new hardware, you not only have to be better than the product of today, but also have to make compelling case for being future-proof.”
For the first time, a team of astronomers has measured the size and structure of a nova’s nuclear blast as it happened.
The discovery of Nova Delphini 2013, along with the data collected about it, could well sharpen or reshape our understanding of the nature of such blasts. The research appears online in the journal Nature.
Novae are found in solar systems with two closely orbiting stellar objects. The gravity from one star, a white dwarf, pulls in hydrogen from the atmosphere of another star, a red giant. This buildup of extra matter on the white dwarf’s surface eventually causes a nuclear detonation.
Tabetha Boyajian, a postdoctoral fellow in Yale’s Department of Astronomy and Astrophysics, had just arrived at California’s Mount Wilson Observatory when word came of a nova that exploded only hours earlier, on August 14, 2013. Boyajian and other researchers quickly put aside their own projects, in order to devote full attention to the phenomenon.
“It’s an opportunity we’ve never had before to see how novae expand,” Boyajian said. “There are all sorts of theories and models of how this material detonates and the processes that follow. But being able to see it happening makes this super, super special.”
What they found was startling in its magnitude. After one day, the size of the nova fireball was equal to the radius of Earth’s orbit. After 43 days, it was the size of our solar system.
The blast expanded at a speed of 1.3 million miles per hour, the research team calculated. In addition, researchers measured the fireball’s brightness and shape.
“A nova has never been studied this way, in this detail,” said Kaspar von Braun, of the Max Planck Institute for Astronomy in Germany, another member of the team. “It all had to be done in express mode.” Almost on a nightly basis, von Braun said, astronomers reconfigured the six telescopes of the observatory’s CHARA Array to gather the necessary data.
The principal investigator for the study was Gail Schaefer, research scientist at the CHARA Array of Georgia State University.
Boyajian said the nova was impressive even without a telescope. “We went outside and we could see it with our eyes,” she said. “We were seeing a star that wasn’t there before. That was pretty awesome.”
At Yale, Boyajian is part of professor Debra Fischer’s team of exoplanet hunters. The team detects and characterizes planets located outside of our solar system.
Newly published research details how a team of scientists used a virtual computer experiment to discover information strings with peculiar properties.
How did life originate? And can scientists create life? These questions not only occupy the minds of scientists interested in the origin of life, but also researchers working with technology of the future. If we can create artificial living systems, we may not only understand the origin of life – we can also revolutionize the future of technology.
Protocells are the simplest, most primitive living systems, you can think of. The oldest ancestor of life on Earth was a protocell, and when we see, what it eventually managed to evolve into, we understand why science is so fascinated with protocells. If science can create an artificial protocell, we get a very basic ingredient for creating more advanced artificial life.
However, creating an artificial protocell is far from simple, and so far no one has managed to do that. One of the challenges is to create the information strings that can be inherited by cell offspring, including protocells. Such information strings are like modern DNA or RNA strings, and they are needed to control cell metabolism and provide the cell with instructions about how to divide.
Essential for life
If one daughter cell after a division has a slightly altered information (maybe it provides a slightly faster metabolism), they may be more fit to survive. Therefor it may be selected and an evolution has started.
Now researchers from the Center for Fundamental Living Technology (FLINT), Department of Physics, Chemistry and Pharmacy, University of Southern Denmark,describe in the journal Europhysics Letters, how they, in a virtual computer experiment, have discovered information strings with peculiar properties.
Professor and head of FLINT, Steen Rasmussen, says:
“Finding mechanisms to create information strings are essential for researchers working with artificial life.”
Steen Rasmussen and his colleagues know they face two problems:
Firstly long molecular strings are decomposed in water. This means that long information strings “break” quickly in water and turn into many short strings. Thus it is very difficult to maintain a population of long strings over time.
Secondly, it is difficult to make these molecules replicate without the use of modern enzymes, whereas it is easier to make a so-called ligation. A ligation is to connect any combination of two shorter strings into a longer string, assisted by another matching longer string. Ligation is the mechanism used by the SDU-researchers.
“In our computer simulation – our virtual molecular laboratory – information strings began to replicate quickly and efficiently as expected. However, we were struck to see that the system quickly developed an equal number of short and long information strings and further that a strong pattern selection on the strings had occurred. We could see that only very specific information patterns on the strings were to be seen in the surviving strings. We were puzzled: How could such a coordinated selection of strings occur, when we knew that we had not programmed it. The explanation had to be found in the way the strings interacted with each other”, explains Steen Rasmussen.
It is like society
According to Steen Rasmussen, a so-called self-organizing autocatalytic network was created in the virtual pot, into which he and his colleagues poured the ingredients for information strings.
An autocatalytic network is a network of molecules, which catalyze each other’s production. Each molecule can be formed by at least one chemical reaction in the network, and each reaction can be catalyzed by at least one other molecule in the network. This process will create a network that exhibits a primitive form of metabolism and an information system that replicates itself from generation to generation.
“An autocatalytic network works like a community; each molecule is a citizen who interacts with other citizens and together they help create a society”, explains Steen Rasmussen.
This autocatalytic set quickly evolved into a state where strings of all lengths existed in equal concentrations, which is not what is usually found. Further, the selected strings had strikingly similar patterns, which is also unusual.
“We might have discovered a process similar to the processes that initially sparked the first life. We of course don’t know if life actually was created this way – but it could have been one of the steps. Perhaps a similar process created sufficiently high concentrations of longer information strings when the first protocell was created”, explains Steen Rasmussen.
Basis for new technology
The mechanisms underlying the formation and selection of effective information strings are not only interesting for the researchers who are working to create protocells. They also have value to researchers working with tomorrow’s technology, like they do at the FLINT Center.
“We seek ways to develop technology that’s based on living and life-like processes. If we succeed, we will have a world where technological devices can repair themselves, develop new properties and be re-used. For example a computer made of biological materials poses very different – and less environmentally stressful – requirements for production and disposal”, says Steen Rasmussen.
Providence, Rhode Island (Brown University) — Superconductors and magnetic fields do not usually get along. But a research team led by a Brown University physicist has produced new evidence for an exotic superconducting state, first predicted a half-century ago, that can indeed arise when a superconductor is exposed to a strong magnetic field.
“It took 50 years to show that this phenomenon indeed happens,” said Vesna Mitrovic, associate professor of physics at Brown University, who led the work. “We have identified the microscopic nature of this exotic quantum state of matter.”
Superconductivity — the ability to conduct electric current without resistance — depends on the formation of electron twosomes known as Cooper pairs (named for Leon Cooper, a Brown University physicist who shared the Nobel Prize for identifying the phenomenon). In a normal conductor, electrons rattle around in the structure of the material, which creates resistance. But Cooper pairs move in concert in a way that keeps them from rattling around, enabling them to travel without resistance.
Magnetic fields are the enemy of Cooper pairs. In order to form a pair, electrons must be opposites in a property that physicists refer to as spin. Normally, a superconducting material has a roughly equal number of electrons with each spin, so nearly all electrons have a dance partner. But strong magnetic fields can flip “spin-down” electrons to “spin-up”, making the spin population in the material unequal.
“The question is what happens when we have more electrons with one spin than the other,” Mitrovic said. “What happens with the ones that don’t have pairs? Can we actually form superconducting states that way, and what would that state look like?”
In 1964, physicists predicted that superconductivity could indeed persist in certain kinds of materials amid a magnetic field. The prediction was that the unpaired electrons would gather together in discrete bands or stripes across the superconducting material. Those bands would conduct normally, while the rest of the material would be superconducting. This modulated superconductive state came to be known as the FFLO phase, named for theorists Peter Fulde, Richard Ferrell, Anatoly Larkin, and Yuri Ovchinniko, who predicted its existence.
To investigate the phenomenon, Mitrovic and her team used an organic superconductor with the catchy name κ-(BEDT-TTF)2Cu(NCS)2. The material consists of ultra-thin sheets stacked on top of each other and is exactly the kind of material predicted to exhibit the FFLO state.
After applying an intense magnetic field to the material, Mitrovic and her collaborators from the French National High Magnetic Field Laboratory in Grenoble probed its properties using nuclear magnetic resonance (NMR).
What they found were regions across the material where unpaired, spin-up electrons had congregated. These “polarized” electrons behave, “like little particles constrained in a box,” Mitrovic said, and they form what are known as Andreev bound states.
“What is remarkable about these bound states is that they enable transport of supercurrents through non-superconducting regions,” Mitrovic said. “Thus, the current can travel without resistance throughout the entire material in this special superconducting state.”
Experimentalists have been trying for years to provide solid evidence that the FFLO state exists, but to little avail. Mitrovic and her colleagues took some counterintuitive measures to arrive at their findings. Specifically, they probed their material at a much higher temperature than might be expected for quantum experiments.
“Normally to observe quantum states you want to be as cold as possible, to limit thermal motion,” Mitrovic said. “But by raising the temperature we increased the energy window of our NMR probe to detect the states we were looking for. That was a breakthrough.”
This new understanding of what happens when electron spin populations become unequal could have implications beyond superconductivity, according to Mitrovic.
It might help astrophysicists to understand pulsars — densely packed neutron stars believed to harbor both superconductivity and strong magnetic fields. It could also be relevant to the field of spintronics, devices that operate based on electron spin rather than charge, made of layered ferromagnetic-superconducting structures.
“This really goes beyond the problem of superconductivity,” Mitrovic said. “It has implications for explaining many other things in the universe, such as behavior of dense quarks, particles that make up atomic nuclei.”
The Ebola virus disease epidemic already devastating swaths of West Africa will likely get far worse in the coming weeks and months unless international commitments are significantly and immediately increased, new research led by Yale researchers predicts.
A team of seven scientists from Yale’s Schools of Public Health and Medicine and the Ministry of Health and Social Welfare in Liberia developed a mathematical transmission model of the viral disease and applied it to Liberia’s most populous county, Montserrado, an area already hard hit. The researchers determined that tens of thousands of new Ebola cases — and deaths — are likely by December 15 if the epidemic continues on its present course.
“Our predictions highlight the rapidly closing window of opportunity for controlling the outbreak and averting a catastrophic toll of new Ebola cases and deaths in the coming months,” said Alison Galvani, professor of epidemiology at the School of Public Health and the paper’s senior author. “Although we might still be within the midst of what will ultimately be viewed as the early phase of the current outbreak, the possibility of averting calamitous repercussions from an initially delayed and insufficient response is quickly eroding.”
The model developed by Galvani and colleagues projects as many as 170,996 total reported and unreported cases of the disease, representing 12% of the overall population of some 1.38 million people, and 90,122 deaths in Montserrado alone by December 15. Of these, the authors estimate 42,669 cases and 27,175 deaths will have been reported by that time.
Much of this suffering — some 97,940 cases of the disease — could be averted if the international community steps up control measures immediately, starting October 31, the model predicts. This would require additional Ebola treatment center beds, a fivefold increase in the speed with which cases are detected, and allocation of protective kits to households of patients awaiting treatment center admission. The study predicts that, at best, just over half as many cases (53,957) can be averted if the interventions are delayed to November 15. Had all of these measures been in place by October 15, the model calculates that 137,432 cases in Montserrado could have been avoided.
There have been approximately 9,000 reported cases and 4,500 deaths from the disease in Liberia, Sierra Leone, and Guinea since the latest outbreak began with a case in a toddler in rural Guinea in December 2013. For the first time cases have been confirmed among health-care workers treating patients in the United States and parts of Europe.
“The current global health strategy is woefully inadequate to stop the current volatile Ebola epidemic,” co-author Dr. Frederick Altice, professor of internal medicine and public health added. “At a minimum, capable logisticians are needed to construct a sufficient number of Ebola treatment units in order to avoid the unnecessary deaths of tens, if not hundreds, of thousands of people.”
Other authors include lead author Joseph Lewnard, Martial L. Ndeffo Mbah, Jorge A. Alfaro-Murillo, Luke Bawo, and Tolbert G. Nyenswah.
The National Institutes of Health funded the study.
A new study from Columbia University Medical Center shows that dietary cocoa flavanols reverse age-related memory decline in healthy older adults.
New York, New York — Dietary cocoa flavanols—naturally occurring bioactives found in cocoa—reversed age-related memory decline in healthy older adults, according to a study led by Columbia University Medical Center (CUMC) scientists. The study,published in the advance online issue of Nature Neuroscience, provides the first direct evidence that one component of age-related memory decline in humans is caused by changes in a specific region of the brain and that this form of memory decline can be improved by a dietary intervention.
As people age, they typically show some decline in cognitive abilities, including learning and remembering such things as the names of new acquaintances or where they parked the car or placed their keys. This normal age-related memory decline starts in early adulthood but usually does not have any noticeable impact on quality of life until people reach their fifties or sixties. Age-related memory decline is different from the often-devastating memory impairment that occurs with Alzheimer’s, in which a disease process damages and destroys neurons in various parts of the brain, including the memory circuits.
Previous work, including by the laboratory of senior author Scott A. Small, MD, had shown that changes in a specific part of the brain—the dentate gyrus—are associated with age-related memory decline. Until now, however, the evidence in humans showed only a correlational link, not a causal one. To see if the dentate gyrus is the source of age-related memory decline in humans, Dr. Small and his colleagues tested whether compounds called cocoa flavanols can improve the function of this brain region and improve memory. Flavanols extracted from cocoa beans had previously been found to improve neuronal connections in the dentate gyrus of mice.
Dr. Small is the Boris and Rose Katz Professor of Neurology (in the Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, the Sergievsky Center, and the Departments of Radiology and Psychiatry) and director of the Alzheimer’s Disease Research Center in the Taub Institute at CUMC.
A cocoa flavanol-containing test drink prepared specifically for research purposes was produced by the food company Mars, Incorporated, which also partly supported the research, using a proprietary process to extract flavanols from cocoa beans. Most methods of processing cocoa remove many of the flavanols found in the raw plant.
The dentate gyrus is distinct from the entorhinal cortex, the hippocampal region affected in early-stage Alzheimer’s disease. Previous work, including by the laboratory of senior author Scott A. Small, MD, had shown that changes in a specific part of the brain’s hippocampus—the dentate gyrus—are associated with normal age-related memory decline in humans and other mammals. (Credit: Columbia University Medical Center)
In the CUMC study, 37 healthy volunteers, ages 50 to 69, were randomized to receive either a high-flavanol diet (900 mg of flavanols a day) or a low-flavanol diet (10 mg of flavanols a day) for three months. Brain imaging and memory tests were administered to each participant before and after the study. The brain imaging measured blood volume in the dentate gyrus, a measure of metabolism, and the memory test involved a 20-minute pattern-recognition exercise designed to evaluate a type of memory controlled by the dentate gyrus.
“When we imaged our research subjects’ brains, we found noticeable improvements in the function of the dentate gyrus in those who consumed the high-cocoa-flavanol drink,” said lead author Adam M. Brickman, PhD, associate professor of neuropsychology at the Taub Institute.
The high-flavanol group also performed significantly better on the memory test. “If a participant had the memory of a typical 60-year-old at the beginning of the study, after three months that person on average had the memory of a typical 30- or 40-year-old,” said Dr. Small. He cautioned, however, that the findings need to be replicated in a larger study—which he and his team plan to do.
Flavanols are also found naturally in tea leaves and in certain fruits and vegetables, but the overall amounts, as well as the specific forms and mixtures, vary widely.
The precise formulation used in the CUMC study has also been shown to improve cardiovascular health. Brigham and Women’s Hospital in Boston recently announced an NIH-funded study of 18,000 men and women to see whether flavanols can help prevent heart attacks and strokes.
The researchers point out that the product used in the study is not the same as chocolate, and they caution against an increase in chocolate consumption in an attempt to gain this effect.
Two innovations by the investigators made the study possible. One was a new information-processing tool that allows the imaging data to be presented in a single three-dimensional snapshot, rather than in numerous individual slices. The tool was developed in Dr. Small’s lab by Usman A. Khan, an MD-PhD student in the lab, and Frank A. Provenzano, a biomedical engineering graduate student at Columbia. The other innovation was a modification to a classic neuropsychological test, allowing the researchers to evaluate memory function specifically localized to the dentate gyrus. The revised test was developed by Drs. Brickman and Small.
Besides flavanols, exercise has been shown in previous studies, including those of Dr. Small, to improve memory and dentate gyrus function in younger people. In the current study, the researchers were unable to assess whether exercise had an effect on memory or on dentate gyrus activity. “Since we didn’t reach the intended VO2max (maximal oxygen uptake) target,” said Dr. Small, “we couldn’t evaluate whether exercise was beneficial in this context. This is not to say that exercise is not beneficial for cognition. It may be that older people need more intense exercise to reach VO2max levels that have therapeutic effects.”
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Targeted Isolation May Be the Most Effective Way to Reduce Transmission of Ebola
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New research led by the Yale School of Public Health shows that isolating 75% of infected individuals in critical condition within four days of symptom onset has a high chance of eliminating the spread of Ebola.
Isolating the most severely ill Ebola patients before the fifth day of their illness may be the most effective way to reduce transmission of the virus, new research led by the Yale School of Public Health suggests.
A team of scientists from Yale and Liberia created a disease transmission model that uses epidemiological and clinical data from Liberia, the country hardest hit by the current outbreak. They found that each infected person is transmitting the disease to 1.73 other people. But people who will eventually die from the disease are spreading it even further, causing 2.36 people to become infected.
The researchers’ model found that isolating 75% of infected individuals in critical condition within four days of symptom onset has a high chance of eliminating the spread of the disease. The research is published October 28 in the Annals of Internal Medicine.
“In the absence of sufficient isolation units, our model emphasizes that targeted isolation of those who are mostly responsible for transmission may be the most efficient way to contain Ebola,” said lead author Dan Yamin, a postdoctoral associate at Yale School of Public health.
Senior author Alison P. Galvani, a professor of epidemiology at the School of Public Health, added, “In particular, infectiousness increases greatly with disease progression, and thus early case-isolation is paramount to reducing household and community transmission.”
This new Ebola transmission model is believed to be the first to consider the effect of disease progression, the rate at which the virus replicates in the body, and the link between the risk of mortality and transmission to others.
The Ebola outbreak now sweeping West Africa is the worst ever recorded. There have been approximately 9,000 reported cases and 4,500 deaths from the disease in Liberia, Sierra Leone, and Guinea since the outbreak began last December. For the first time, cases have been confirmed among healthcare workers treating patients in the United States and parts of Europe. Co-author Dr. Frederick Altice, professor of internal medicine and public health added, “Lessons from Liberia and this modeling study have important implications for the ill-advised current quarantine regulations that have been imposed in several states, which are not based on solid public health principles.”
The researchers acknowledge that the model has several limitations, including projections that are based upon initial dynamics of the epidemic. While these projections may change as the outbreak and interventions evolve, note the researchers, they nonetheless suggest that effective isolation, through the construction of sufficient numbers of Ebola isolation units is crucial to containing the epidemic.
Other authors on the study included Shai Gertler, Martial L. Ndeffo-Mbah, Laura A. Skrip, Mosoka Fallah, and Tolbert G. Nyenswah.
The National Institutes of Public Health funded the study.
New research shows that delivering chemotherapy directly into the brain cavity may kill tumor cells in the brain more effectively and avoid side effects.
Every year, about 100,000 Americans are diagnosed with brain tumors that have spread from elsewhere in the body. These tumors, known as metastases, are usually treated with surgery followed by chemotherapy, but the cancer often returns.
A new study from MIT, Brigham and Women’s Hospital, and Johns Hopkins University suggests that delivering chemotherapy directly into the brain cavity may offer a better way to treat tumors that have metastasized to the brain.
Testing their new approach in mice, the researchers found that the chemotherapy drug temozolomide (TMZ) was more effective when delivered via tiny capsules implanted inside the skull. This suggests that a similar approach might be more effective in human patients, says Michael Cima, the David H. Koch Professor of Engineering at MIT and a senior author of the study, which appears this week in the Proceedings of the National Academy of Sciences.
“Metastatic disease should be sensitive to chemotherapy, but systemic chemotherapy has not proven effective because it’s not getting to the brain at a high enough dose for a long enough period of time,” says Cima, who is also a member of MIT’s Koch Institute for Integrative Cancer Research. “We’re showing we get much higher degrees of tumor cell death when we deliver the drug locally.”
The paper’s other senior authors are Robert Langer, the David H. Koch Institute Professor at MIT and a member of the Koch Institute, the Institute for Medical Engineering and Science (IMES), and the Department of Chemical Engineering, and Henry Brem, a professor of neurosurgery at Johns Hopkins. The lead author is Urvashi Upadhyay, previously a neurosurgeon at Brigham and Women’s Hospital and now an assistant professor of neurosurgery at the University of Massachusetts Medical School.
Targeted delivery
Chemotherapy drugs are usually delivered via intravenous injection. To make sure that enough reaches a tumor, very large quantities must be given, often producing side effects.
For a few types of cancer, doctors have developed more targeted approaches. With ovarian cancer, the best results are achieved when drugs are delivered directly into the abdominal cavity. However, this is not widely done because it requires implanting a catheter in the patient for 12 weeks, which is difficult for the patients to tolerate.
“There are already established methods for improving patient care,” Cima says. “There just aren’t good ways to do it.” To overcome these delivery issues, Cima’s lab is working on small implantable devices to deliver drugs for ovarian cancer and bladder disease, as well as brain cancer.
For the new brain study, the researchers delivered chemotherapy drugs via implantable microcapsules made of a biocompatible material called liquid crystal polymer. The capsules are small cylinders with a 1.5-milliliter drug capacity; the drug diffuses out through a small hole. These are experimental devices the researchers selected to test whether the concept of local delivery would work, but they were so effective in this study that Cima says they may end up being the most promising vehicle for potential human clinical trials.
The researchers tested two chemotherapy agents: TMZ, which is a first-line treatment for brain metastasis and gliomas, and doxorubicin, a common treatment for breast cancer, which often metastasizes to the brain.
Zone of influence
Working with mice implanted with tumors similar to human brain metastases, the researchers found that TMZ delivered directly to the brain prolonged survival by several days compared with TMZ administered by injection. They also found higher rates of apoptosis, or programmed cell death, in tumor cells near the capsules. However, doxorubicin delivered to the brain did not perform as well as systemic injection of doxorubicin.
As an explanation for that discrepancy, the researchers found that TMZ travels farther from the capsule after release, allowing it to reach more tissue. Doxorubicin appears to be broken down or cleared before it can kill as many cells, Cima says. This could be valuable information in designing future versions of this treatment for brain tumors or other cancers, he adds.
“The properties of the drug molecule have to be taken into account in the design of local therapy that’s effective,” says Cima. “There’s a zone around each one of these devices where it can work, depending on the molecule.”
Michael Lim, an associate professor of neurosurgery at Johns Hopkins, says the new approach seems like a promising way to expand the range of treatments available for brain tumors, which are now limited because it is so difficult to get chemotherapy drugs to cross the blood-brain barrier.
“This could potentially positively impact patients’ lives,” says Lim, who was not involved in the study. “After they have their brain metastases surgically taken out, you could put in these microcapsules, which would kill any remaining cancer cells right then and there.”
Although there are still many hurdles to developing this approach to treat human cancer, Cima says he believes it is worth pursuing because so many cancers, particularly those of the breast and lung, spread to the brain. The researchers are also working on using this approach to precisely deliver drugs to very small regions of the brain, in hopes of developing better treatments for psychiatric and neurodegenerative disorders.
The research was funded by the National Institutes of Health and the Brain Science Foundation.
A team of scientists has calculated the risk for a worst-case scenario upper limit for sea level rise within this century, revealing that the sea level could rise 1.8 meters.
The climate is getting warmer, the ice sheets are melting and sea levels are rising – but how much? The report of the UN’s Intergovernmental Panel on Climate Change (IPCC) in 2013 was based on the best available estimates of future sea levels, but the panel was not able to come up with an upper limit for sea level rise within this century. Now researchers from the Niels Bohr Institute and their colleagues have calculated the risk for a worst-case scenario. The results indicate that at worst, the sea level would rise a maximum of 1.8 meters. The results are published in the scientific journal Environmental Research Letters.
What causes the sea to rise is when all the water that is now frozen as ice and lies on land melts and flows into the sea. It is first and foremost about the two large, kilometer-thick ice sheets on Greenland and Antarctica, but also mountain glaciers.
In addition, large amounts of groundwater is pumped for both drinking water and agricultural use in many parts of the world and more groundwater is pumped than seeps back down into the ground, so this water also ends up in the oceans.
Finally, what happens is that when the climate gets warmer, the oceans also get warmer and hot water expands and takes up more space. But how much do the experts expect the sea levels to rise during this century at the maximum?
Melting of the ice sheets
“We wanted to try to calculate an upper limit for the rise in sea level and the biggest question is the melting of the ice sheets and how quickly this will happen. The IPCC restricted their projektions to only using results based on models of each process that contributes to sea level. But the greatest uncertainty in assessing the evolution of sea levels is that ice sheet models have only a limited ability to capture the key driving forces in the dynamics of the ice sheets in relation to climatic impact,” Aslak Grinsted, Associate Professor at the Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen.
Aslak Grinsted has therefore, in collaboration with researchers from England and China, worked out new calculations. The researchers have combined the IPCC numbers with published data about the expectations within the ice-sheet expert community for the evolution, including the risk for the collapse of parts of Antarctica and how quickly such a collapse would take place.
“We have created a picture of the propable limits for how much global sea levels will rise in this century. Our calculations show that the seas will likely rise around 80 cm. An increase of more than 180 cm has a likelihood of less than 5 percent. We find that a rise in sea levels of more than 2 meters is improbable,” Aslak Grinsted, but points that the results only concern this century and the sea levels will continue to rise for centuries to come.
Earth’s magnetic field is decreasing 10 times faster than normal, leading some geophysicists to predict a magnetic reversal to occur within a few thousand years. New research from an international team of scientists shows that this reversal could happen over a short period of time – less than a hundred years.
Berkeley — Imagine the world waking up one morning to discover that all compasses pointed south instead of north.
It’s not as bizarre as it sounds. Earth’s magnetic field has flipped – though not overnight – many times throughout the planet’s history. Its dipole magnetic field, like that of a bar magnet, remains about the same intensity for thousands to millions of years, but for incompletely known reasons it occasionally weakens and, presumably over a few thousand years, reverses direction.
Now, a new study by a team of scientists from Italy, France, Columbia University and the University of California, Berkeley, demonstrates that the last magnetic reversal 786,000 years ago actually – roughly a human lifetime.
“It’s amazing how rapidly we see that reversal,” said UC Berkeley graduate student Courtney Sprain. “The paleomagnetic data are very well done. This is one of the best records we have so far of what happens during a reversal and how quickly these reversals can happen.”
Sprain and Paul Renne, director of the Berkeley Geochronology Center and a UC Berkeley professor-in- residence of earth and planetary science, are coauthors of the study, which is published in the November issue of Geophysical Journal International.
Flip could affect electrical grid, cancer rates
The discovery comes as new evidence indicates that the intensity of Earth’s magnetic field is decreasing 10 times faster than normal, leading some geophysicists to predict a reversal within a few thousand years.
Though a magnetic reversal is a major planet-wide event driven by convection in Earth’s iron core, there are no documented catastrophes associated with past reversals, despite much searching in the geologic and biologic record. Today, however, such a reversal could potentially wreak havoc with our electrical grid, generating currents that might take it down.
And since Earth’s magnetic field protects life from energetic particles from the sun and cosmic rays, both of which can cause genetic mutations, a weakening or temporary loss of the field before a permanent reversal could increase cancer rates. The danger to life would be even greater if flips were preceded by long periods of unstable magnetic behavior.
“We should be thinking more about what the biologic effects would be,” Renne said.
Dating ash deposits from windward volcanoes
The new finding is based on measurements of the magnetic field alignment in layers of ancient lake sediments now exposed in the Sulmona basin of the Apennine Mountains east of Rome, Italy. The lake sediments are interbedded with ash layers erupted from the Roman volcanic province, a large area of volcanoes upwind of the former lake that includes periodically erupting volcanoes near Sabatini, Vesuvius and the Alban Hills.
Italian researchers led by Leonardo Sagnotti of Rome’s National Institute of Geophysics and Volcanology measured the magnetic field directions frozen into the sediments as they accumulated at the bottom of the ancient lake.
Sprain and Renne used argon-argon dating, a method widely used to determine the ages of rocks, whether they’re thousands or billions of years old, to determine the age of ash layers above and below the sediment layer recording the last reversal. These dates were confirmed by their colleague and former UC Berkeley postdoctoral fellow Sebastien Nomade of the Laboratory of Environmental and Climate Sciences in Gif-Sur-Yvette, France.
Because the lake sediments were deposited at a high and steady rate over a 10,000-year period, the team was able to interpolate the date of the layer showing the magnetic reversal, called the Matuyama-Brunhes transition, at approximately 786,000 years ago. This date is far more precise than that from previous studies, which placed the reversal between 770,000 and 795,000 years ago.
“What’s incredible is that you go from reverse polarity to a field that is normal with essentially nothing in between, which means it had to have happened very quickly, probably in less than 100 years,” said Renne. “We don’t know whether the next reversal will occur as suddenly as this one did, but we also don’t know that it won’t.”
Unstable magnetic field preceded 180-degree flip
Whether or not the new finding spells trouble for modern civilization, it likely will help researchers understand how and why Earth’s magnetic field episodically reverses polarity, Renne said.
The magnetic record the Italian-led team obtained shows that the sudden 180-degree flip of the field was preceded by a period of instability that spanned more than 6,000 years. The instability included two intervals of low magnetic field strength that lasted about 2,000 years each. Rapid changes in field orientations may have occurred within the first interval of low strength. The full magnetic polarity reversal – that is, the final and very rapid flip to what the field is today – happened toward the end of the most recent interval of low field strength.
Renne is continuing his collaboration with the Italian-French team to correlate the lake record with past climate change.
Renne and Sprain’s work at the Berkeley Geochronology Center was supported by the Ann and Gordon Getty Foundation.
