Handheld spectral analyzer turns smartphone into diagnostic tool


Scienceadaily.com - Researchers at the University of Illinois at Urbana-Champaign have developed technology that enables a smartphone to perform lab-grade medical diagnostic tests that typically require large, expensive instruments. Costing only $550, the spectral transmission-reflectance-intensity (TRI)-Analyzer from Bioengineering and Electrical & Computer Engineering Professor Brian Cunningham's lab attaches to a smartphone and analyzes patient blood, urine, or saliva samples as reliably as clinic-based instruments that cost thousands of dollars.

"Our TRI Analyzer is like the Swiss Army knife of biosensing," said Cunningham, the Donald Biggar Willett Professor of Engineering and director of the Micro + Nanotechnology Lab at Illinois. "It's capable of performing the three most common types of tests in medical diagnostics, so in practice, thousands of already-developed tests could be adapted to it."

In a recently published paper, Cunningham's team used the TRI Analyzer to perform two commercially available assays -- a test to detect a biomarker associated with pre-term birth in pregnant women and the PKU test for newborns to indirectly detect an enzyme essential for normal growth and development. Their tests results were comparable to those acquired with clinic-grade spectrometer instrumentation.

"The TRI Analyzer is more of a portable laboratory than a specialized device," said Kenny Long, an MD/PhD student and lead author of the research study.

Among the many diagnostic tests that can be adapted to their point-of-care smartphone format, Long said, is an enzyme-linked immunosorbent assay (ELISA), which detects and measures a wide variety of proteins and antibodies in blood and is commonly used for a wide range of health diagnostics tests. The system is capable of detecting the output of any test that uses a liquid that changes color, or a liquid that generates light output (such as from fluorescent dyes).

The TRI Analyzer operates by converting the smartphone camera into a high-performance spectrometer. Specifically, the analyzer illuminates a sample fluid with the phone's internal white LED flash or with an inexpensive external green laser diode. The light from the sample is collected in an optical fiber and guided through a diffraction grating into the phone's rear-facing internal camera. These optical components are all arranged within a 3D-printed plastic cradle.

The TRI Analyzer can simultaneously measure multiple samples by using a microfluidic cartridge that slides through an opening in the back of the cradle. This ability to analyze multiple samples quickly and reliably makes the Analyzer suitable for patients who lack convenient access to a clinic or hospital with diagnostic test facilities or for patients with urgent health situations requiring rapid results.

"Our Analyzer can scan many tests in a sequence by swiping the cartridge past the readout head, in a similar manner to the way magnetic strip credit cards are swiped," said Long.

In addition to its applications in health diagnostics, Cunningham said the TRI Analyzer can also be applied to point-of use applications that include animal health, environmental monitoring, drug testing, manufacturing quality control, and food safety. The patented technology is available for license.

Source : University of Illinois College of Engineering

Lunar dynamo’s lifetime extended by at least 1 billion years


Scienceadaily.com - New evidence from ancient lunar rocks suggests that an active dynamo once churned within the molten metallic core of the moon, generating a magnetic field that lasted at least 1 billion years longer than previously thought. Dynamos are natural generators of magnetic fields around terrestrial bodies, and are powered by the churning of conducting fluids within many stars and planets. In a paper published today in Science Advances, researchers from MIT and Rutgers University report that a lunar rock collected by NASA's Apollo 15 mission exhibits signs that it formed 1 to 2.5 billion years ago in the presence of a relatively weak magnetic field of about 5 microtesla. That's around 10 times weaker than Earth's current magnetic field but still 1,000 times larger than fields in interplanetary space today.

Several years ago, the same researchers identified 4-billion-year-old lunar rocks that formed under a much stronger field of about 100 microtesla, and they determined that the strength of this field dropped off precipitously around 3 billion years ago. At the time, the researchers were unsure whether the moon's dynamo -- the related magnetic field -- died out shortly thereafter or lingered in a weakened state before dissipating completely.

The results reported today support the latter scenario: After the moon's magnetic field dwindled, it nonetheless persisted for at least another billion years, existing for a total of at least 2 billion years.

Study co-author Benjamin Weiss, professor of planetary sciences in MIT's Department of Earth, Atmospheric and Planetary Sciences (EAPS), says this new extended lifetime helps to pinpoint the phenomena that powered the moon's dynamo. Specifically, the results raise the possibility of two different mechanisms -- one that may have driven an earlier, much stronger dynamo, and a second that kept the moon's core simmering at a much slower boil toward the end of its lifetime.

"The concept of a planetary magnetic field produced by moving liquid metal is an idea that is really only a few decades old," Weiss says. "What powers this motion on Earth and other bodies, particularly on the moon, is not well-understood. We can figure this out by knowing the lifetime of the lunar dynamo."

Weiss' co-authors are lead author Sonia Tikoo, a former MIT graduate student who is now an assistant professor at Rutgers; David Shuster of the University of California at Berkeley; Clément Suavet and Huapei Wang of EAPS; and Timothy Grove, the R.R. Schrock Professor of Geology and associate head of EAPS.

Apollo's glassy recorders

Since NASA's Apollo astronauts brought back samples from the lunar surface, scientists have found some of these rocks to be accurate "recorders" of the moon's ancient magnetic field. Such rocks contain thousands of tiny grains that, like compass needles, aligned in the direction of ancient fields when the rocks crystallized eons ago. Such grains can give scientists a measure of the moon's ancient field strength.

Until recently, Weiss and others had been unable to find samples much younger than 3.2 billion years old that could accurately record magnetic fields. As a result, they had only been able to gauge the strength of the moon's magnetic field between 3.2 and 4.2 billion years ago.

"The problem is, there are very few lunar rocks that are younger than about 3 billion years old, because right around then, the moon cooled off, volcanism largely ceased and, along with it, formation of new igneous rocks on the lunar surface," Weiss explains. "So there were no young samples we could measure to see if there was a field after 3 billion years."

There is, however, a small class of rocks brought back from the Apollo missions that formed not from ancient lunar eruptions but from asteroid impacts later in the moon's history. These rocks melted from the heat of such impacts and recrystallized in orientations determined by the moon's magnetic field.

Weiss and his colleagues analyzed one such rock, known as Apollo 15 sample 15498, which was originally collected on Aug. 1, 1971, from the southern rim of the moon's Dune Crater. The sample is a mix of minerals and rock fragments, welded together by a glassy matrix, the grains of which preserve records of the moon's magnetic field at the time the rock was assembled.

"We found that this glassy material that welds things together has excellent magnetic recording properties," Weiss says.

Baking rocks

The team determined that the rock sample was about 1 to 2.5 billion years old -- much younger than the samples they previously analyzed. They developed a technique to decipher the ancient magnetic field recorded in the rock's glassy matrix by first measuring the rock's natural magnetic properties using a very sensitive magnetometer.

They then exposed the rock to a known magnetic field in the lab, and heated the rock to close to the extreme temperatures in which it originally formed. They measured how the rock's magnetization changed as they increased the surrounding temperature.

"You see how magnetized it gets from getting heated in that known magnetic field, then you compare that field to the natural magnetic field you measured beforehand, and from that you can figure out what the ancient field strength was," Weiss explains.

The researchers did have to make one significant adjustment to the experiment to better simulate the original lunar environment, and in particular, its atmosphere. While the Earth's atmosphere contains around 20 percent oxygen, the moon has only imperceptible traces of the gas. In collaboration with Grove, Suavet built a customized, oxygen-deprived oven in which to heat the rocks, preventing them from rusting while at the same time simulating the oxygen-free environment in which the rocks were originally magnetized.

"In this way, we finally have gotten an accurate measurement of the lunar field," Weiss says.

From ice cream makers to lava lamps

From their experiments, the researchers determined that, around 1 to 2.5 billion years ago, the moon harbored a relatively weak magnetic field, with a strength of about 5 microtesla -- two orders of magnitude weaker than the moon's field around 3 to 4 billion years ago. Such a dramatic dip suggests to Weiss and his colleagues that the moon's dynamo may have been driven by two distinct mechanisms.

Scientists have proposed that the moon's dynamo may have been powered by the Earth's gravitational pull. Early in its history, the moon orbited much closer to the Earth, and the Earth's gravity, in such close proximity, may have been strong enough to pull on and rotate the rocky exterior of the moon. The moon's liquid center may have been dragged along with the moon's outer shell, generating a very strong magnetic field in the process.

It's thought that the moon may have moved sufficiently far away from the Earth by about 3 billion years ago, such that the power available for the dynamo by this mechanism became insufficient. This happens to be right around the time the moon's magnetic field strength dropped. A different mechanism may have then kicked in to sustain this weakened field. As the moon moved away from the Earth, its core likely sustained a low boil via a slow process of cooling over at least 1 billion years.

"As the moon cools, its core acts like a lava lamp -- low-density stuff rises because it's hot or because its composition is different from that of the surrounding fluid," Weiss says. "That's how we think the Earth's dynamo works, and that's what we suggest the late lunar dynamo was doing as well."

The researchers are planning to analyze even younger lunar rocks to determine when the dynamo died off completely.

"Today the moon's field is essentially zero," Weiss says. "And we now know it turned off somewhere between the formation of this rock and today."

This research was supported, in part, by NASA.

Source : Massachusetts Institute of Technology

Brain Cells Found to Control Aging


Scienceadaily.com - Scientists at Albert Einstein College of Medicine have found that stem cells in the brain's hypothalamus govern how fast aging occurs in the body. The finding, made in mice, could lead to new strategies for warding off age-related diseases and extending lifespan. The paper was published online today in Nature.

The hypothalamus was known to regulate important processes including growth, development, reproduction and metabolism. In a 2013 Nature paper, Einstein researchers made the surprising finding that the hypothalamus also regulates aging throughout the body. Now, the scientists have pinpointed the cells in the hypothalamus that control aging: a tiny population of adult neural stem cells, which were known to be responsible for forming new brain neurons.

"Our research shows that the number of hypothalamic neural stem cells naturally declines over the life of the animal, and this decline accelerates aging," says senior author Dongsheng Cai, M.D., Ph.D., (professor of molecular pharmacology at Einstein. "But we also found that the effects of this loss are not irreversible. By replenishing these stem cells or the molecules they produce, it's possible to slow and even reverse various aspects of aging throughout the body."

In studying whether stem cells in the hypothalamus held the key to aging, the researchers first looked at the fate of those cells as healthy mice got older. The number of hypothalamic stem cells began to diminish when the animals reached about 10 months, which is several months before the usual signs of aging start appearing. "By old age -- about two years of age in mice -- most of those cells were gone," says Dr. Cai.

The researchers next wanted to learn whether this progressive loss of stem cells was actually causing aging and was not just associated with it. So they observed what happened when they selectively disrupted the hypothalamic stem cells in middle-aged mice. "This disruption greatly accelerated aging compared with control mice, and those animals with disrupted stem cells died earlier than normal," says Dr. Cai.

Could adding stem cells to the hypothalamus counteract aging? To answer that question, the researchers injected hypothalamic stem cells into the brains of middle-aged mice whose stem cells had been destroyed as well as into the brains of normal old mice. In both groups of animals, the treatment slowed or reversed various measures of aging.

Dr. Cai and his colleagues found that the hypothalamic stem cells appear to exert their anti-aging effects by releasing molecules called microRNAs (miRNAs). They are not involved in protein synthesis but instead play key roles in regulating gene expression. miRNAs are packaged inside tiny particles called exosomes, which hypothalamic stem cells release into the cerebrospinal fluid of mice.

The researchers extracted miRNA-containing exosomes from hypothalamic stem cells and injected them into the cerebrospinal fluid of two groups of mice: middle-aged mice whose hypothalamic stem cells had been destroyed and normal middle-aged mice. This treatment significantly slowed aging in both groups of animals as measured by tissue analysis and behavioral testing that involved assessing changes in the animals' muscle endurance, coordination, social behavior and cognitive ability.

The researchers are now trying to identify the particular populations of microRNAs and perhaps other factors secreted by these stem cells that are responsible for these anti-aging effects -- a first step toward possibly slowing the aging process and treating age-related diseases.

The article is titled, "Hypothalamic stem cells control ageing speed partly through exosomal miRNAs." The other authors are Yalin Zhang. Ph.D., Min Soo Kim, Ph.D., Baosen Jia, Ph.D., Jingqi Yan, Ph.D., Juan Pablo Zuniga-Hertz, Ph.D., and Cheng Han, Ph.D., all at Einstein.

The study was supported by grants from the National Institutes of Health (DK078750, AG031774 , HL113180, and DK099136).

Scientists Restore Youthful Plasticity to the Brains of Adult Mice


Scienceadaily.com - Like much of the rest of the body, the brain loses flexibility with age, impacting the ability to learn, remember, and adapt. Now, scientists at University of Utah Health report they can rejuvenate the plasticity of the mouse brain, specifically in the visual cortex, increasing its ability to change in response to experience. Manipulating a single gene triggers the shift, revealing it as a potential target for new treatments that could recover the brain's youthful potential. The research was published online in the Proceedings of the National Academy of Sciences (PNAS) on August 8.

"It's exciting because it suggests that by just manipulating one gene in adult brains, we can boost brain plasticity," says lead investigator Jason Shepherd, Ph.D., Associate Professor of Neurobiology and Anatomy at University of Utah Health.

"This has implications for potentially reducing normal cognitive decline with aging, or boosting recovery from brain injury after stroke or traumatic brain injury," he says. Additional research will need to be done to determine whether plasticity in humans and mice is regulated in the same way.

The dramatic way in which the brain changes over time has long captured the imagination of scientists. A "critical window" of brain plasticity explains why certain eye conditions such as lazy eye can be corrected during early childhood but not later in life. The phenomenon has raised the questions: What ordinarily keeps the window open? And, once it's shut, can plasticity be restored?

Earlier work that Shepherd carried out in collaboration with Mark Bear, Ph.D., a professor at the Massachusetts Institute of Technology and co-author of the current study, showed that the critical window never opens in mice lacking a gene called Arc. Temporarily closing a single eye of a young mouse for a few days deprives the visual cortex of normal input, and the neurons' electrophysiological response to visual experience changes. By contrast, young mice without Arc cannot adapt to the new experience in the same way.

"Given our previous studies, we wondered whether Arc is essential for controlling the critical period of plasticity during normal brain development," says Shepherd.

If there is no visual plasticity without Arc, the thinking goes, then perhaps the gene plays a role in keeping the "critical window" open.

In support of the idea, the new investigation finds that in the mouse visual cortex, Arc rises and falls in parallel with visual plasticity. The two peak in teen mice and fall sharply by middle-age, suggesting they are linked.

The researchers probed the connection further in two more ways. First, in collaboration with co-author Harohiko Bito, Ph.D., a professor at the University of Tokyo, they tested mice that have a strong supply of Arc throughout life. At middle-age, these mice responded to visual deprivation as robustly as their juvenile counterparts. By prolonging Arc's availability, the window of plasticity remained open for longer.

Manipulating Arc is not the first treatment to prolong plasticity. Chronically treating mice with an antidepressant, fluoxetine, and raising rodents in a stimulating environment with toys and plenty of social interaction, are among other paradigms that do the same.

But the second set of experiments raised the bar higher. Viruses were used to deliver Arc to middle age mice, after the critical window had closed. Following the intervention, these older mice responded to visual deprivation as a youngster woulds. In this case even though the window had already shut, Arc enabled it to open once again.

"It was incredible to see that in adult mice, who have gone through normal development and aging, simply overexpressing Arc with a virus restored plasticity," says co-first author Kyle Jenks, a graduate student in Shepherd's lab.

The prevailing notion of how plasticity declines is that as the brain develops, inhibitory neurons mature and become stronger. Shepherd explains that he believes their findings add a new dimension for how critical periods of learning are regulated.

"Increased inhibition in the brain makes it harder to express activity-dependent genes, like Arc, in response to experience or learning," he says. "And that leads to decreased brain plasticity."

Normally, Arc is rapidly activated in response to stimuli and is involved in shuttling neurotransmitter receptors out of synapses that neurons use to communicate with one another. Additional research will need to be done to understand precisely how manipulating Arc boosts plasticity.

Whether Arc is involved in regulating the plasticity of other neurological functions mediated by other brain structures, like learning, memory, or repair, remains to be tested but will be examined in the future, says Shepherd.

Source : University of Utah Health

DNA from Viking cod bones suggests 1,000 years of European fish trade


Scienceadaily.com - Norway is famed for its cod. Catches from the Arctic stock that spawns each year off its northern coast are exported across Europe for staple dishes from British fish and chips to Spanish bacalao stew.

Now, a new study published today in the journal PNAS suggests that some form of this pan-European trade in Norwegian cod may have been taking place for 1,000 years.

Latest research from the universities of Cambridge and Oslo, and the Centre for Baltic and Scandinavian Archaeology in Schleswig, used ancient DNA extracted from the remnants of Viking-age fish suppers.

The study analysed five cod bones dating from between 800 and 1066 AD found in the mud of the former wharves of Haithabu, an early medieval trading port on the Baltic. Haithabu is now a heritage site in modern Germany, but at the time was ruled by the King of the Danes.

The DNA from these cod bones contained genetic signatures seen in the Arctic stock that swims off the coast of Lofoten: the northern archipelago still a centre for Norway's fishing industry.

Researchers say the findings show that supplies of 'stockfish' -- an ancient dried cod dish popular to this day -- were transported over a thousand miles from northern Norway to the Baltic Sea during the Viking era.

Prior to the latest study, there was no archaeological or historical proof of a European stockfish trade before the 12th century.

While future work will look at further fish remains, the small size of the current study prevents researchers from determining whether the cod was transported for trade or simply used as sustenance for the voyage from Norway.

However, they say that the Haithabu bones provide the earliest evidence of fish caught in northern Norway being consumed on mainland Europe -- suggesting a European fish trade involving significant distances has been in operation for a millennium.

"Traded fish was one of the first commodities to begin to knit the European continent together economically," says Dr James Barrett, senior author of the study from the University of Cambridge's McDonald Institute for Archaeological Research.

"Haithabu was an important trading centre during the early medieval period. A place where north met south, pagan met Christian, and those who used coin met those who used silver by weight."

"By extracting and sequencing DNA from the leftover fish bones of ancient cargoes at Haithabu, we have been able to trace the source of their food right the way back to the cod populations that inhabit the Barents Sea, but come to spawn off Norway's Lofoten coast every winter.

"This Arctic stock of cod is still highly prized -- caught and exported across Europe today. Our findings suggest that distant requirements for this Arctic protein had already begun to influence the economy and ecology of Europe in the Viking age."

Stockfish is white fish preserved by the unique climate of north Norway, where winter temperature hovers around freezing. Cod is traditionally hung out on wooden frames to allow the chill air to dry the fish. Some medieval accounts suggest stockfish was still edible as much as ten years after preservation.

The research team argue that the new findings offer some corroboration to the unique 9th century account of the voyages of Ohthere of Hålogaland: a Viking chieftain whose visit to the court of King Alfred in England resulted in some of his exploits being recorded.

"In the accounts inserted by Alfred's scribes into the translation of an earlier 5th century text, Ohthere describes sailing from Hålogaland to Haithabu," says Barrett. Hålogaland was the northernmost province of Norway.

"While no cargo of dried fish is mentioned, this may be because it was simply too mundane a detail," says Barrett. "The fish-bone DNA evidence is consistent with the Ohthere text, showing that such voyages between northern Norway and mainland Europe were occurring."

"The Viking world was complex and interconnected. This is a world where a chieftain from north Norway may have shared stockfish with Alfred the Great while a late-antique Latin text was being translated in the background. A world where the town dwellers of a cosmopolitan port in a Baltic fjord may have been provisioned from an Arctic sea hundreds of miles away."

The sequencing of the ancient cod genomes was done at the University of Oslo, where researchers are studying the genetic makeup of Atlantic cod in an effort to unpick the anthropogenic impacts on these long-exploited fish populations.

"Fishing, particularly of cod, has been of central importance for the settlement of Norway for thousands of years. By combining fishing in winter with farming in summer, whole areas of northern Norway could be settled in a more reliable manner," says the University of Oslo's Bastiaan Star, first author of the new study.

Star points to the design of Norway's new banknotes that prominently feature an image of cod, along with a Viking ship, as an example of the cultural importance still placed on the fish species in this part of Europe.

"We want to know what impact the intensive exploitation history covering millennia has inflicted on Atlantic cod, and we use ancient DNA methods to investigate this," he says.

The study was funded by the Research Council of Norway and the Leverhulme Trust.

Source : University of Cambridge

Microbe New to Science Found in Self-fermented Beer


Scienceadaily.com - In May 2014, a group of scientists took a field trip to a small brewery in an old warehouse in Seattle, Washington. They were looking for some yeast to sequence—and to taste some beer, if it came down to it. Cody Morris, then brewmaster of Epic Ales, ushered them through the building, warning of a large hole in the floor. Then he brought the group over to one of the old wine casks in which Morris was brewing a “wild beer.”

“We opened it and it was alive,” says Maitreya Dunham, a geneticist at the University of Washington in Seattle who led the sudsy expedition. The liquid in the barrel was bubbling away vigorously. “It was definitely an actively fermenting mixture,” she says.

Whereas standard beers like Heineken or Sierra Nevada are produced by adding one type of yeast—usually a Saccharomyces species—wild brewers like Morris coax a community of bugs from the environment to settle in and ferment beer, an old Belgian tradition. But like many brewers making wild beers, Morris admitted he had no idea what microbes were living in the barrel staves that had inoculated his beer. Could the scientists figure it out?

The team accepted the challenge. Dunham and her colleagues collected a bit of the company's “Old Warehouse” beer into a plastic tube. If it was a mixture of microbes, it would be the perfect sample for a technique she and her colleagues were developing called Hi-C sequencing, which disentangles the genomic sequences of a community of microbe species using formaldehyde to link DNA fragments within the same cell. “The inference is that if two pieces of DNA are crosslinking to each other, they must have come from the same cell,” Dunham explains.

What she found got her excited. Using the Hi-C technique, the team identified a yeast belonging to the genus Pichia, which turned out to be a hybrid of a known species called P. membranifaciens and another Pichia species completely new to science, the team recently reported on the preprint server bioRxiv. (Such yeast hybrids are common in brewing; in fact, lager yeast was recently discovered to be a hybrid of two Saccharomyces species.) The scientists dubbed the new hybrid Pichia apotheca–Greek for “warehouse.”

The brew also contained Saccharomyces and yet another yeast genus, Brettanomyces, which is found in many wild beers and sold commercially. In addition, the mix contained Lactobacillus, Pediococcus, and Acetobacter bacteria, all known to imbue a sour character to a beer.

Dunham's team tried to brew a beer with P. apotheca alone, but that didn't work; the yeast produced little alcohol. That's not unusual; most yeasts found in mixed cultures won't brew a beer well on their own. But the hybrid may contribute to Old Warehouse's taste, the researchers write in their paper. Other Pichia species are known to spoil a beer, but the new hybrid seems to smell better, Dunham says. She's open to providing brewers with microbe isolates, if they want to experiment with them.

“This paper provides a proof-of-concept for using this method to study other spontaneously fermented beers,” says Ronn Friedlander, a co-founder of Aeronaut Brewing in Somerville, Massachusetts, who has a Ph.D. in bioengineering. What’s also striking, he says, is that the mixture Dunham and her team identified is very close to the “Roeselare” blend that commercial yeast provider Wyeast markets to brewers who want to inoculate a wild beer artificially. That mix contains a Belgian-style ale strain, Saccharomyces, two Brettanomyces strains, Lactobacillus, and Pediococcus, Friedlander says.

Perhaps wild beer fermentation is a more predictable process than once thought, Friedlander says. “This might point to specific niches that must be filled in a microbially stable, aging beer,” he says.

And that means brewers and scientists may be one step closer to unveiling the alchemy of spontaneous fermentation.

Source : Sciencemag

SwRI Part of International Team Identifying Primordial Asteroids

Astronomers have identified the oldest asteroid families and, by process of elimination, the oldest intact asteroids in the main belt. A team including SwRI scientists developed a technique to identify ancient asteroid families that have drifted apart. Asteroid surfaces heat up during the day (as illustrated by this image) and cool down at night, giving off radiation that can act as a sort of mini-thruster. This force can cause asteroids to drift widely over time, making it difficult to identify families of fragments leftover after asteroid collisions eons ago.
Scienceadaily.com - Southwest Research Institute (SwRI) was part of an international team that recently discovered a relatively unpopulated region of the main asteroid belt, where the few asteroids present are likely pristine relics from early in solar system history. The team used a new search technique that also identified the oldest known asteroid family, which extends throughout the inner region of the main asteroid belt.

The main belt contains vast numbers of irregularly shaped asteroids, also known as planetesimals, orbiting the Sun between Mars and Jupiter. As improved telescope technology finds smaller and more distant asteroids, astronomers have identified clusters of similar-looking bodies clumped in analogous orbits. These familial objects are likely fragments of catastrophic collisions between larger asteroids eons ago. Finding and studying asteroid families allows scientists to better understand the history of main belt asteroids.

“By identifying all the families in the main belt, we can figure out which asteroids have been formed by collisions and which might be some of the original members of the asteroid belt,” said SwRI Astronomer Dr. Kevin Walsh, a coauthor of the online Science paper detailing the findings. “We identified all known families and their members and discovered a gigantic void in the main belt, populated by only a handful of asteroids. These relics must be part of the original asteroid belt. That is the real prize, to know what the main belt looked like just after it formed.”

Identifying the very oldest asteroid families, those billions of years old, is challenging, because over time, a family spreads out. As asteroids rotate in orbit around the Sun, their surfaces heat up during the day and cool down at night. This creates radiation that can act as a sort of mini-thruster, causing asteroids to drift widely over time. After billions of years, family members would be almost impossible to identify, until now. The team used a novel technique, searching asteroid data from the inner region of the belt for old, dispersed families. They looked for the “edges” of families, those fragments that have drifted the furthest.

“Each family member drifts away from the center of the family in a way that depends on its size, with small guys drifting faster and further than the larger guys,” said team leader Marco Delbo, an astronomer from the Observatory of Cote d’Azur in Nice, France. “If you look for correlations of size and distance, you can see the shapes of old families.”

“The family we identified has no name, because it is not clear which asteroid is the parent,” Walsh said. “This family is so old that it appears to have formed over 4 billion years ago, before the gas giants in the outer solar system moved into their current orbits. The giant planet migration shook up the asteroid belt, removing many bodies, possibly including the parent of this family.”

The team plans to apply this new technique to the entire asteroid belt to reveal more about the history of the solar system by identifying the primordial asteroids versus fragments of collisions. This research was supported by the French National Program of Planetology and the National Science Foundation. The resulting paper, “Identification of a primordial asteroid family constrains the original planetesimal population,” appears in the August 3, 2017, online edition of Science.

Source : Southwest Research Institute

Ancient Mars impacts created tornado-like winds that scoured surface


Scienceadaily.com - In looking at NASA images of Mars a few years ago, Brown University geologist Peter Schultz noticed sets of strange bright streaks emanating from a few large-impact craters on the planet's surface. The streaks are odd in that they extend much farther from the craters than normal ejecta patterns, and they are only visible in thermal infrared images taken during the Martian night.

Using geological observation, laboratory impact experiments and computer modeling, Schultz and Brown graduate student Stephanie Quintana have offered a new explanation for how those streaks were formed. They show that tornado-like wind vortices -- generated by crater-forming impacts and swirling at 500 miles per hour or more -- scoured the surface and blasted away dust and small rocks to expose the blockier surfaces beneath.


"This would be like an F8 tornado sweeping across the surface," Schultz said. "These are winds on Mars that will never be seen again unless another impact."

The research is published online in the journal Icarus.

Schultz says he first saw the streaks during one of his "tours of Mars." In his downtime between projects, he pulls up random images from NASA's orbital spacecraft just to see if he might spot something interesting. In this case, he was looking at infrared images taken during the Martian nighttime by the THEMIS instrument, which flies aboard the Mars Odyssey orbiter.

The infrared images capture contrasts in heat retention on the surface. Brighter regions at night indicate surfaces that retain more heat from the previous day than surrounding surfaces, just as grassy fields cool off at night while buildings in the city remain warmer.

"You couldn't see these things at all in visible wavelength images, but in the nighttime infrared they're very bright," Schultz said. "Brightness in the infrared indicates blocky surfaces, which retain more heat than surfaces covered by powder and debris. That tells us that something came along and scoured those surfaces bare."

And Schultz had an idea what that something might be. He has been studying impacts and impact processes for years using NASA's Vertical Gun Range, a high-powered cannon that can fire projectiles at speeds up to 15,000 miles per hour.

"We had been seeing some things in experiments we thought might cause these streaks," he said.

When an asteroid or other body strikes a planet at high speed, tons of material from both the impactor and the target surface are instantly vaporized. Schultz's experiments showed that vapor plumes travel outward from an impact point, just above the impact surface, at incredible speeds. Scaling laboratory impacts to the size of those on Mars, a vapor plume's speed would be supersonic. And it would interact with the Martian atmosphere to generate powerful winds.

The plume and its associated winds on their own didn't cause the strange streaks, however. The plumes generally travel just above the surface, which prevents the kind of deep scouring seen in the streaked areas. But Schultz and Quintana showed that when the plume strikes a raised surface feature, it disturbs the flow and causes powerful tornadic vortices to form and drop to the surface. And those vortices, the researchers say, are responsible for scouring the narrow streaks.

Schultz and Quintana showed that the streaks are nearly always seen in conjunction with raised surface features. Very often, for example, they are associated with the raised ridges of smaller impact craters that were already in place when the larger impact occurred. As the plume raced outward from the larger impact, it encountered the small crater rim, leaving bright twin streaks on the downwind side.

"Where these vortices encounter the surface, they sweep away the small particles that sit loose on the surface, exposing the bigger blocky material underneath, and that's what gives us these streaks," Schultz said.

Schultz says the streaks could prove useful in establishing rates of erosion and dust deposition in areas where the streaks are found.

"We know these formed at the same time as these large craters, and we can date the age of the craters," Schultz said. "So now we have a template for looking at erosion."

But with more research, the streaks could eventually reveal much more than that. From a preliminary survey of the planet, the researchers say the streaks appear to form around craters in the ballpark of 20 kilometers across. But they don't appear in all such craters. Why they form in some places and not others could provide information about the Martian surface at the time of the impact.

The researchers' experiments reveal that the presence of volatile compounds -- a thick layer of water ice on the surface or subsurface, for example -- affect the amount the vapor that rushes out from an impact. So in that way, the streaks might serve as indicators of whether ice may have been present at the time of an impact, which could lend insight into reconstructions of past climate on Mars. Equally possible, the streaks could be related to the composition of the impactor, such as rare collisions by high-volatile objects, such as comets.

"The next step is to really dig into the conditions that cause the streaks," Schultz said. "They may have a lot to tell us, so stay tuned."

Source : Brown University

The Mysterious Powers of Spider Silks

Scienceadaily.com - Spider silks, the stuff of spider webs, are a materials engineer’s dream: they can be stronger than steel at a mere fraction of weight, and also can be tougher and more flexible. Spider silks also tend not to provoke the human immune system. Some even inhibit bacteria and fungi, making them potentially ideal for surgery and medical device applications. Exploitation of these natural marvels has been slow, due in part to the challenges involved in identifying and characterizing spider silk genes, but researchers from the Perelman School of Medicine at the University of Pennsylvania have now made a major advance with the largest-ever study of spider silk genes.

As they report today in an advance online paper in Nature Genetics, Penn scientists and their collaborators sequenced the full genome of the golden orb-weaver spider (Nephila clavipes), a prolific silk-spinner that turns out to produce 28 varieties of silk proteins. In addition to cataloguing new spider silk genes, the researchers discovered novel patterns within the genes that may help to explain the unique properties of different types of silk.


“There were so many surprises that emerged from our study: new silk genes, new DNA sequences that presumably confer strength, toughness, stretchiness and other properties to silk proteins; and even a silk protein made in venom glands rather than silk glands,” said senior author Benjamin F. Voight, PhD, an associate professor in the departments of Genetics and Systems Pharmacology and Translational Therapeutics. “All this new information should greatly advance our efforts to capture the extraordinary properties of these silks in man-made materials.”

Even though spider silks have been studied for more than 50 years, earlier foundational work had identified only a comparative handful of spider silk genes. Even recent work from species with smaller silk repertoires than the golden orb-weaver’s were incomplete. To find all of the silk genes hidden across the golden orb-weaver’s genome—the veritable “lab rat” of spider silk science—required the construction of the entire genome, a daunting task in itself.

In the new study, Voight and his colleagues began with the herculean task of sequencing and reassembling the genome of the golden orb-weaver: a task comparable to solving a multimillion-piece jigsaw puzzle, with few clues as to how these pieces fit together.

In the golden orb-weaver’s genome—which turns out to be about as large as the human genome—the researchers identified more than 14,000 likely genes, including 28 that appear to encode spider silk proteins, known as spidroins.

Spidroins have been classified into seven categories according to their protein sequences and functions; these categories include aciniform silk for wrapping prey (and tying down partners for mating); and the super-strong major ampullate silk from which spiders (and Spider-Man) swing while at work. However, some of the newly discovered spidroins have sequences that do not fit neatly into any of these categories—suggesting that the encoded silk proteins may have novel functions, or that the existing categories need to be redefined.

An extensive computational analysis of the orb-weaver’s spidroin genes revealed nearly 400 short sequences—many never before described—that appear repeatedly in these genes with small variations and in different combinations. These repetitive spidroin “motifs” are of great interest to biologists and engineers because they are likely to confer the key properties of a given spider silk, such as high tensile strength, flexibility, or stickiness. The analysis also revealed novel, higher-order organizations of these motifs into groups of motifs (“cassettes”) and groups of groups (“ensembles”).
Voight’s team also examined gene transcripts from different orb-weaver silk glands and in each case found transcripts belonging to more than one spidroin class, suggesting that these glands are not strictly specialized for producing one type of silk. “We found significantly more complexity in silk production than we expected,” Voight said.

The biggest surprise was the discovery that one of the orb-weaver’s spidroins—FLAG-b, a novel discovery by the group—appears to be produced primarily in the orb-weaver’s venom gland rather than in any silk gland, hinting at intriguing new functions for silk connected to prey capture, immobilization, or preservation.

In their analyses of the genome data, Voight and colleagues also identified 649 likely genes that are not spidroin genes but are highly expressed in silk glands, and thus probably have roles in converting the liquid silk from spider cells into solid, spinnable threads—a tricky process that biotech engineers are just beginning to achieve outside of spiders.

Voight and his team are now following up with a genome-sequencing study of Darwin’s bark spider, which makes the strongest known silks, and has been known to span rivers with them.
The scientists are also at work on technology for the rapid production of silks in the lab starting from their spidroin DNA sequences, to better understand how these sequences and their motifs encode silks’ biological and physical properties.

“When I say that we’d like to build a ‘web-shooter’ like Spider-Man’s in the lab, I’m only half joking” Voight said.

Source :  University of Pennsylvania School of Medicine

Oxford Student Creates First Synthetic Retina

Scienceadaily.com - A synthetic, soft tissue retina developed by an Oxford University student could offer fresh hope to visually impaired people.

Until now, all artificial retinal research has used only rigid, hard materials. The new research, by Vanessa Restrepo-Schild, a 24 year old Dphil student and researcher at the Oxford University, Department of Chemistry, is the first to successfully use biological, synthetic tissues, developed in a laboratory environment. The study could revolutionise the bionic implant industry and the development of new, less invasive technologies that more closely resemble human body tissues, helping to treat degenerative eye conditions such as retinitis pigmentosa.


Just as photography depends on camera pixels reacting to light, vision relies on the retina performing the same function. The retina sits at the back of the human eye, and contains protein cells that convert light into electrical signals that travel through the nervous system, triggering a response from the brain, ultimately building a picture of the scene being viewed.

Vanessa Restrepo-Schild led the team in the development of a new synthetic, double layered retina which closely mimics the natural human retinal process. The retina replica consists of soft water droplets (hydrogels) and biological cell membrane proteins. Designed like a camera, the cells act as pixels, detecting and reacting to light to create a grey scale image.  The Colombian native said: ‘The synthetic material can generate electrical signals, which stimulate the neurons at the back of our eye just like the original retina.’

The study, published in the journal Scientific Reports, shows that unlike existing artificial retinal implants, the cell-cultures are created from natural, biodegradable materials and do not contain foreign bodies or living entities. In this way the implant is less invasive than a mechanical devise, and is less likely to have an adverse reaction on the body.  Miss Restrepo-Schild added: ‘The human eye is incredibly sensitive, which is why foreign bodies like metal retinal implants can be so damaging, leading to inflammation and/or scaring. But a biological synthetic implant is soft and water based, so much more friendly to the eye environment.’

Of the motivation behind the ground-breaking study,  Miss Restrepo-Schild said: ‘I have always been fascinated by the human body, and want to prove that current technology can be used to replicate the function of human tissues, without having to actually use living cells.

I have taken the principals behind vital bodily functions, e.g. our sense of hearing, touch and the ability to detect light, and replicated them in a laboratory environment with natural, synthetic components. I hope my research is the first step in a journey towards building technology that is soft and biodegradable instead of hard and wasteful.’

Although at present the synthetic retina has only been tested in laboratory conditions, Miss Restrepo-Schild is keen to build on her initial work and explore potential uses with living tissues. This next step is vital in demonstrating how the material performs as a bionic implant.

Miss Restrepo-Schild has filed a patent for the technology and the next phase of the work will see the Oxford team expand the replica’s function to include recognising different colours. Working with a much larger replica, the team will test the material’s ability to recognise different colours and potentially even shapes and symbols. Looking further ahead the research will expand to include animal testing and then a series of clinical trials in humans.

Source : University of Oxford

Astronomers Confirm Nearby Star a Good Model of Our Early Solar System

Scienceadaily.com - NASA's SOFIA aircraft, a 747 loaded with a 2.5-meter telescope in the back and stripped of most creature comforts in the front, took a big U-turn over the Pacific west of Mexico.

The Stratospheric Observatory for Infrared Astronomy aircraft was just beginning the second half of an overnight mission on Jan. 28, 2015. It turned north for a flight all the way to western Oregon, then back home to NASA's Armstrong Flight Research Center in Palmdale, California. Along the way, pilots steered the plane to aim the telescope at a nearby star.

This is an artist's illustration of the epsilon Eridani system showing Epsilon Eridani b, right foreground, a Jupiter-mass planet orbiting its parent star at the outside edge of an asteroid belt. In the background can be seen another narrow asteroid or comet belt plus an outermost belt similar in size to our solar system's Kuiper Belt. The similarity of the structure of the Epsilon Eridani system to our solar system is remarkable, although Epsilon Eridani is much younger than our sun. SOFIA observations confirmed the existence of the asteroid belt adjacent to the orbit of the Jovian planet. Larger illustration. Illustration by NASA/SOFIA/Lynette Cook.

Iowa State University's Massimo Marengo and other astronomers were on board to observe the mission and collect infrared data about the star.

That star is called epsilon Eridani. It's about 10 light years away from the sun. It's similar to our sun, but one-fifth the age. And astronomers believe it can tell them a lot about the development of our solar system.

Marengo, an Iowa State associate professor of physics and astronomy, and other astronomers have been studying the star and its planetary system since 2004. In a 2009 scientific paper, the astronomers used data from NASA's Spitzer Space Telescope to describe the star's disk of fine dust and debris left over from the formation of planets and the collisions of asteroids and comets. They reported the disk contained separate belts of asteroids, similar to the asteroid and Kuiper belts of our solar system.

Subsequent studies by other astronomers questioned that finding.

A new scientific paper, just published online by The Astronomical Journal, uses SOFIA and Spitzer data to confirm there are separate inner and outer disk structures. The astronomers report further studies will have to determine if the inner disk includes one or two debris belts.

Kate Su, an associate astronomer at the University of Arizona and the university's Steward Observatory, is the paper's lead author. Marengo is one of the paper's nine co-authors.

Marengo said the findings are important because they confirm epsilon Eridani is a good model of the early days of our solar system and can provide hints at how our solar system evolved.

"This star hosts a planetary system currently undergoing the same cataclysmic processes that happened to the solar system in its youth, at the time in which the moon gained most of its craters, Earth acquired the water in its oceans, and the conditions favorable for life on our planet were set," Marengo wrote in a summary of the project.

A major contributor to the new findings was data taken during that January 2015 flight of SOFIA. Marengo joined Su on the cold and noisy flight at 45,000 feet, above nearly all of the atmospheric water vapor that absorbs the infrared light that astronomers need to see planets and planetary debris.

Determining the structure of the disk was a complex effort that took several years and detailed computer modeling. The astronomers had to separate the faint emission of the disk from the much brighter light coming from the star.

"But we can now say with great confidence that there is a separation between the star's inner and outer belts," Marengo said. "There is a gap most likely created by planets. We haven't detected them yet, but I would be surprised if they are not there. Seeing them will require using the next-generation instrumentation, perhaps NASA's 6.5-meter James Webb Space Telescope scheduled for launch in October 2018."

That's a lot of time and attention on one nearby star and its debris disk. But Marengo said it really is taking astronomers back in time.

"The prize at the end of this road is to understand the true structure of epsilon Eridani's out-of-this-world disk, and its interactions with the cohort of planets likely inhabiting its system," Marengo wrote in a newsletter story about the project. "SOFIA, by its unique ability of capturing infrared light in the dry stratospheric sky, is the closest we have to a time machine, revealing a glimpse of Earth's ancient past by observing the present of a nearby young sun."

Source : Iowa State University

How Stable Manure Protects Against Allergies

Scienceadaily.com - Improved hygiene has largely eliminated infectious diseases from everyday life. There is, however, a downside to this progress: the number of allergies is growing steadily. If the immune system is not kept busy by bacteria, viruses and worms, it sometimes overreacts to harmless things like pollen.


Researchers funded by the SNSF have now investigated the mechanism underlying the "farmhouse effect", which indicates that children who grow up on a farm are less likely to suffer from allergies. "We can only use superficial parameters to study children's immune systems," says lead investigator Philippe Eigenmann from Geneva University Hospitals. "This is why we wanted to study the allergic reaction of mice in detail."

Laboratory mice in the cowshed

For the experiment, the research group working with Eigenmann transferred mice directly to a cowshed in Vollèges near Martigny (Valais), the first time this had been done for an allergy study. Mice born on the farm reacted less intensely to an artificial allergen than those born in the laboratory. This was determined by measuring the extent of ear swelling. Mice that were not transferred to the cowshed until four weeks after birth were slightly less well protected. This finding is consistent with data from earlier studies in humans. Eigenmann adds: "Children of farmers' wives who worked in animal sheds while they were pregnant accordingly have even fewer problems with allergies."

Why probiotic foods don't really work

A comparison of cells and signalling substances in the immune system also shows that the reactions differ considerably. The immune defence of the farm-born mice was constantly activated but at the same time powerfully regulated by germs from the cowshed. "The immune system evidently learns to moderate its response," Eigenmann explains.

The animals' gut flora also differed depending on their living conditions. The diversity of bacteria was greater in the intestinal tract of farm mice, and a certain type of virus was present in larger quantities. These mastadenoviruses could be the factor that is moderating immune response.

The changes in gut flora and the immune system were many and varied, which explains why certain preventive measures based on administration of individual germs have little effect. The bacterial strains in probiotic foods such as yogurts are one example. Another is the administration of deactivated thread worm eggs. "We need to take as global an approach as possible to the factors and rethink our concept of cleanliness," Eigenmann explains.

Source : Swiss National Science Foundation (SNSF)

Clinical Guidelines to Prevent Peanut Allergy

Scienceadaily.com - An expert panel sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, issued clinical guidelines today to aid health care providers in early introduction of peanut-containing foods to infants to prevent the development of peanut allergy.

Peanut allergy is a growing health problem for which no treatment or cure exists. People living with peanut allergy, and their caregivers, must be vigilant about the foods they eat and the environments they enter to avoid allergic reactions, which can be severe and even life-threatening. The allergy tends to develop in childhood and persist through adulthood. However, recent scientific research has demonstrated that introducing peanut-containing foods into the diet during infancy can prevent the development of peanut allergy.


The new Addendum Guidelines for the Prevention of Peanut Allergy in the United States supplement the 2010 Guidelines for the Diagnosis and Management of Food Allergy in the United States (link is external). The addendum provides three separate guidelines for infants at various levels of risk for developing peanut allergy and is targeted to a wide variety of health care providers, including pediatricians and family practice physicians.

“Living with peanut allergy requires constant vigilance. Preventing the development of peanut allergy will improve and save lives and lower health care costs,” said NIAID Director Anthony S. Fauci, M.D. “We expect that widespread implementation of these guidelines by health care providers will prevent the development of peanut allergy in many susceptible children and ultimately reduce the prevalence of peanut allergy in the United States.”

Addendum Guideline 1 focuses on infants deemed at high risk of developing peanut allergy because they already have severe eczema, egg allergy or both. The expert panel recommends that these infants have peanut-containing foods introduced into their diets as early as 4 to 6 months of age to reduce the risk of developing peanut allergy. Parents and caregivers should check with their infant’s health care provider before feeding the infant peanut-containing foods. The health care provider may choose to perform an allergy blood test or send the infant to a specialist for other tests, such as a skin prick test or an oral food challenge. The results of these tests will help decide if and how peanut should be safely introduced into the infant’s diet.

Guideline 2 suggests that infants with mild or moderate eczema should have peanut-containing foods introduced into their diets around 6 months of age to reduce the risk of peanut allergy. Guideline 3 suggests that infants without eczema or any food allergy have peanut-containing foods freely introduced into their diets.

In all cases, infants should start other solid foods before they are introduced to peanut-containing foods.

Development of the Addendum Guidelines was prompted by emerging data suggesting that peanut allergy can be prevented by the early introduction of peanut-containing foods. Clinical trial results reported in February 2015 showed that regular peanut consumption begun in infancy and continued until 5 years of age led to an 81 percent reduction in development of peanut allergy in infants deemed at high risk because they already had severe eczema, egg allergy or both. This finding came from the landmark, NIAID-funded Learning Early About Peanut Allergy (LEAP) (link is external)study, a randomized clinical trial involving more than 600 infants.

“The LEAP study clearly showed that introduction of peanut early in life significantly lowered the risk of developing peanut allergy by age 5. The magnitude of the benefit and the scientific strength of the study raised the need to operationalize these findings by developing clinical recommendations focused on peanut allergy prevention,” said Daniel Rotrosen, M.D., director of NIAID’s Division of Allergy, Immunology and Transplantation.

In 2015, NIAID established a coordinating committee representing 26 professional organizations, advocacy groups and federal agencies to oversee development of the Addendum Guidelines to specifically address the prevention of peanut allergy. The coordinating committee convened a 26-member expert panel comprising specialists from a variety of relevant clinical, scientific and public health areas. The panel, chaired by Joshua Boyce, M.D., professor of medicine and pediatrics at Harvard Medical School, used a literature review of food allergy prevention research and their own expert opinions to prepare draft guidelines. The draft guidelines were available on the NIAID website for public comment from March 4 to April 18, 2016. The expert panel and coordinating committee reviewed the 104 comments received to develop the final Addendum Guidelines.

Source : NIH/National Institute of Allergy and Infectious Diseases

Could Parkinson’s Disease Start in the Gut?

Scienceadaily.com - Parkinson’s disease may start in the gut and spread to the brain via the vagus nerve, according to a study published in the April 26, 2017, online issue of Neurology®, the medical journal of the American Academy of Neurology. The vagus nerve extends from the brainstem to the abdomen and controls unconscious body processes like heart rate and food digestion.

The preliminary study examined people who had resection surgery, removing the main trunk or branches of the vagus nerve. The surgery, called vagotomy, is used for people with ulcers. Researchers used national registers in Sweden to compare 9,430 people who had a vagotomy over a 40-year period to 377,200 people from the general population. During that time, 101 people who had a vagotomy developed Parkinson’s disease, or 1.07 percent, compared to 4,829 people in the control group, or 1.28 percent. This difference was not significant.

Parkinson's disease may start in the gut and spread to the brain, according to a study.  Credit : wikimedia.org

But when researchers analyzed the results for the two different types of vagotomy surgery, they found that people who had a truncal vagotomy at least five years earlier were less likely to develop Parkinson’s disease than those who had not had the surgery and had been followed for at least five years. In a truncal vagotomy, the nerve trunk is fully resected. In a selective vagotomy, only some branches of the nerve are resected.

A total of 19 people who had truncal vagotomy at least five years earlier developed the disease, or 0.78 percent, compared to 3,932 people who had no surgery and had been followed for at least five years, at 1.15 percent. By contrast, 60 people who had selective vagotomy five years earlier developed Parkinson’s disease, or 1.08 percent. After adjusting for factors such as chronic obstructive pulmonary disease, diabetes, arthritis and other conditions, researchers found that people who had a truncal vagotomy at least five years before were 40 percent less likely to develop Parkinson’s disease than those who had not had the surgery and had been followed for at least five years.

“These results provide preliminary evidence that Parkinson’s disease may start in the gut,” said study author Bojing Liu, MSc, of the Karolinska Instituet in Stockholm, Sweden. “Other evidence for this hypothesis is that people with Parkinson’s disease often have gastrointestinal problems such as constipation, that can start decades before they develop the disease. In addition, other studies have shown that people who will later develop Parkinson’s disease have a protein believed to play a key role in Parkinson’s disease in their gut.”

The theory is that these proteins can fold in the wrong way and spread that mistake from cell to cell.

“Much more research is needed to test this theory and to help us understand the role this may play in the development of Parkinson’s,” Liu said. Additionally, since Parkinson’s is a syndrome, there may be multiple causes and pathways.

Even though the study was large, Liu said one limitation was small numbers in certain subgroups. Also, the researchers could not control for all potential factors that could affect the risk of Parkinson’s disease, such as smoking, coffee drinking or genetics.

Source : News Wise

Ripples in the Cosmic Web

Scienceadaily.com - The far-flung corners of intergalactic space are lonely places, barren of much else but atoms. In these vast expanses between the galaxies, only atoms — a haze of hydrogen gas left over from the Big Bang — occupy solitary cubes one meter on a side. On the largest scale, this diffuse material is arranged in a network of filamentary structures known as the “cosmic web,” its tangled strands spanning billions of light years and accounting for the majority of atoms in the universe.

Now, a team of astronomers, including UC Santa Barbara physicist Joseph Hennawi, have made the first measurements of small-scale ripples in this primeval hydrogen gas using rare double quasars. Although the regions of cosmic web they studied lie nearly 11 billion light years away, they were able to measure variations in its structure on scales 100,000 times smaller, comparable to the size of a single galaxy. The results appear in the journal Science.

This schematic representation illustrates the technique used to probe the small-scale structure of the cosmic web using light from a rare quasar pair. Photo Credit: J. ONORBE / MPIA

Intergalactic gas is so tenuous that it emits no light of its own. Instead astronomers study it indirectly by observing how it selectively absorbs the light coming from faraway sources known as quasars. Quasars constitute a brief hyperluminous phase of the galactic life cycle powered by matter falling into a galaxy’s central supermassive black hole. Acting like cosmic lighthouses, they are bright, distant beacons that allow astronomers to study intergalactic atoms residing between the location of the quasar and the Earth. But because these hyperluminous episodes last only a tiny fraction of a galaxy’s lifetime, quasars are correspondingly rare and are typically separated from each other by hundreds of millions of light years.

In order to probe the cosmic web on much smaller length scales, the astronomers exploited a fortuitous cosmic coincidence: They identified exceedingly rare pairs of quasars and measured subtle differences in the absorption of intergalactic atoms along the two sightlines.

“Pairs of quasars are like needles in a haystack,” explained Hennawi,  an associate professor in UCSB’s Department of Physics who pioneered the application of algorithms from “machine learning” — a brand of artificial intelligence — to efficiently locate quasar pairs in the massive amounts of data produced by digital imaging surveys of the night sky. “In order to find them, we combed through images of billions of celestial objects millions of times fainter than what the naked eye can see.”

Once identified, the quasar pairs were observed with the largest telescopes in the world, including the 10-meter Keck telescopes at the W.M. Keck Observatory on Mauna Kea, Hawaii, of which the University of California is a founding partner.

“One of the biggest challenges was developing the mathematical and statistical tools to quantify the tiny differences we measured in this new kind of data,” said lead author Alberto Rorai, Hennawi’s former Ph.D. student who is now a postdoctoral researcher at Cambridge University. Rorai developed these tools as part of the research for his doctoral degree and applied them to spectra of quasars with Hennawi and other colleagues.

The astronomers compared their measurements to supercomputer models that simulate the formation of cosmic structures from the Big Bang to the present. On a single laptop, these complex calculations would require almost 1,000 years to complete, but modern supercomputers enabled the researchers to carry them out in just a few weeks.

“The input to our simulations are the laws of physics and the output is an artificial universe, which can be directly compared to astronomical data,” said co-author Jose Oñorbe, a postdoctoral researcher at the Max Planck Institute for Astronomy in Heidelberg, Germany, who led the supercomputer simulation effort. “I was delighted to see that these new measurements agree with the well-established paradigm for how cosmic structures form.”

“One reason why these small-scale fluctuations are so interesting is that they encode information about the temperature of gas in the cosmic web just a few billion years after the Big Bang,” explained Hennawi.

Astronomers believe that the matter in the universe went through phase transitions billions of years ago, which dramatically changed its temperature. Known as cosmic re-ionization, these transitions occurred when the collective ultraviolet glow of all stars and quasars in the universe became intense enough to strip electrons off atoms in intergalactic space. How and when re-ionization occurred is one of the biggest open questions in the field of cosmology, and these new measurements provide important clues that will help narrate this chapter of cosmic history.

Source : University of California - Santa Barbara

Ice Cave in Transylvania Yields Window into Region's Past

Scienceadaily.com - Ice cores drilled from a glacier in a cave in Transylvania offer new evidence of how Europe's winter weather and climate patterns fluctuated during the last 10,000 years, known as the Holocene period.

The cores provide insights into how the region's climate has changed over time. The researchers' results, published this week in the journal Scientific Reports, could help reveal how the climate of the North Atlantic region, which includes the U.S., varies on long time scales.

The project, funded by the National Science Foundation (NSF) and the Romanian Ministry of Education, involved scientists from the University of South Florida (USF), University of Belfast, University of Bremen and Stockholm University, among other institutions.

Panoramic view of an ice cliff inside the Scărișoara Ice Cave, where the research was done. Credit: Gigi Fratila & Claudiu Szabo

Researchers from the Emil Racoviță Institute of Speleology in Cluj-Napoca, Romania, and USF's School of Geosciences gathered their evidence in the world's most-explored ice cave and oldest cave glacier, hidden deep in the heart of Transylvania in central Romania.

With its towering ice formations and large underground ice deposit, Scărișoara Ice Cave is among the most important scientific sites in Europe.

Scientist Bogdan Onac of USF and his colleague Aurel Perșoiu, working with a team of researchers in Scărișoara Ice Cave, sampled the ancient ice there to reconstruct winter climate conditions during the Holocene period.

Over the last 10,000 years, snow and rain dripped into the depths of Scărișoara, where they froze into thin layers of ice containing chemical evidence of past winter temperature changes.

Until now, scientists lacked long-term reconstructions of winter climate conditions. That knowledge gap hampered a full understanding of past climate dynamics, Onac said.

"Most of the paleoclimate records from this region are plant-based, and track only the warm part of the year -- the growing season," says Candace Major, program director in NSF's Directorate for Geosciences, which funded the research. "That misses half the story. The spectacular ice cave at Scărișoara fills a crucial piece of the puzzle of past climate change in recording what happens during winter."

Reconstructions of Earth's climate record have relied largely on summer conditions, charting fluctuations through vegetation-based samples, such as tree ring width, pollen and organisms that thrive in the warmer growing season.

Absent, however, were important data from winters, Onac said.

Located in the Apuseni Mountains, the region surrounding the Scărișoara Ice Cave receives precipitation from the Atlantic Ocean and the Mediterranean Sea and is an ideal location to study shifts in the courses storms follow across East and Central Europe, the scientists say.

Radiocarbon dating of minute leaf and wood fragments preserved in the cave's ice indicates that its glacier is at least 10,500 years old, making it the oldest cave glacier in the world and one of the oldest glaciers on Earth outside the polar regions.

From samples of the ice, the researchers were able to chart the details of winter conditions growing warmer and wetter over time in Eastern and Central Europe. Temperatures reached a maximum during the mid-Holocene some 7,000 to 5,000 years ago and decreased afterward toward the Little Ice Age, 150 years ago.

A major shift in atmospheric dynamics occurred during the mid-Holocene, when winter storm tracks switched and produced wetter and colder conditions in northwestern Europe, and the expansion of a Mediterranean-type climate toward southeastern Europe.

"Our reconstruction provides one of the very few winter climate reconstructions, filling in numerous gaps in our knowledge of past climate variability," Onac said.

Warming winter temperatures led to rapid environmental changes that allowed the northward expansion of Neolithic farmers toward mainland Europe, and the rapid population of the continent.

"Our data allow us to reconstruct the interplay between Atlantic and Mediterranean sources of moisture," Onac said. "We can also draw conclusions about past atmospheric circulation patterns, with implications for future climate changes. Our research offers a long-term context to better understand these changes."

The results from the study tell scientists how the climate of the North Atlantic region, which includes the U.S., varies on long time scales. The scientists are continuing their cave study, working to extend the record back 13,000 years or more.

Source : National Science Foundation

3-D Printing Offers New Approach to Making Buildings

Scienceadaily.com - The list of materials that can be produced by 3-D printing has grown to include not just plastics but also metal, glass, and even food. Now, MIT researchers are expanding the list further, with the design of a system that can 3-D print the basic structure of an entire building.

Structures built with this system could be produced faster and less expensively than traditional construction methods allow, the researchers say. A building could also be completely customized to the needs of a particular site and the desires of its maker. Even the internal structure could be modified in new ways; different materials could be incorporated as the process goes along, and material density could be varied to provide optimum combinations of strength, insulation, or other properties.

Ultimately, the researchers say, this approach could enable the design and construction of new kinds of buildings that would not be feasible with traditional building methods.

MIT researchers have designed a system that can 3-D print the basic structure of an entire building. The system consists of a tracked vehicle that carries a large industrial robotic arm, which has a smaller, precision-motion robotic arm at its end.

The robotic system is described this week in the journal Science Robotics, in a paper by Steven Keating PhD ’16, a mechanical engineering graduate and former research affiliate in the Mediated Matter group at the MIT Media Lab; Julian Leland and Levi Cai, both research assistants in the Mediated Matter group; and Neri Oxman, group director and associate professor of media arts and sciences.

The system consists of a tracked vehicle that carries a large, industrial robotic arm, which has a smaller, precision-motion robotic arm at its end. This highly controllable arm can then be used to direct any conventional (or unconventional) construction nozzle, such as those used for pouring concrete or spraying insulation material, as well as additional digital fabrication end effectors, such as a milling head.

Unlike typical 3-D printing systems, most of which use some kind of an enclosed, fixed structure to support their nozzles and are limited to building objects that can fit within their overall enclosure, this free-moving system can construct an object of any size. As a proof of concept, the researchers used a prototype to build the basic structure of the walls of a 50-foot-diameter, 12-foot-high dome — a project that was completed in less than 14 hours of “printing” time.

For these initial tests, the system fabricated the foam-insulation framework used to form a finished concrete structure. This construction method, in which polyurethane foam molds are filled with concrete, is similar to traditional commercial insulated-concrete formwork techniques. Following this approach for their initial work, the researchers showed that the system can be easily adapted to existing building sites and equipment, and that it will fit existing building codes without requiring whole new evaluations, Keating explains.

Ultimately, the system is intended to be self-sufficient. It is equipped with a scoop that could be used to both prepare the building surface and acquire local materials, such as dirt for a rammed-earth building, for the construction itself. The whole system could be operated electrically, even powered by solar panels. The idea is that such systems could be deployed to remote regions, for example in the developing world, or to areas for disaster relief after a major storm or earthquake, to provide durable shelter rapidly.



The ultimate vision is “in the future, to have something totally autonomous, that you could send to the moon or Mars or Antarctica, and it would just go out and make these buildings for years,” says Keating, who led the development of the system as his doctoral thesis work.

But in the meantime, he says, “we also wanted to show that we could build something tomorrow that could be used right away.” That’s what the team did with its initial mobile platform. “With this process, we can replace one of the key parts of making a building, right now,” he says. “It could be integrated into a building site tomorrow.”

“The construction industry is still mostly doing things the way it has for hundreds of years,” says Keating. “The buildings are rectilinear, mostly built from single materials, put together with saws and nails,” and mostly built from standardized plans.

But, Keating wondered, what if every building could be individualized and designed using on-site environmental data? In the future, the supporting pillars of such a building could be placed in optimal locations based on ground-penetrating radar analysis of the site, and walls could have varying thickness depending on their orientation. For example, a building could have thicker, more insulated walls on its north side in cold climates, or walls that taper from bottom to top as their load-bearing requirements decrease, or curves that help the structure withstand winds.

The creation of this system, which the researchers call a Digital Construction Platform (DCP), was motivated by the Mediated Matter group’s overall vision of designing buildings without parts. Such a vision includes, for example, combining “structure and skin,” and beams and windows, in a single production process, and adapting multiple design and construction processes on the fly, as the structure is being built.

From an architectural perspective, Oxman says, the project “challenges traditional building typologies such as walls, floors, or windows, and proposes that a single system could be fabricated using the DCP that can vary its properties continuously to create wall-like elements that continuously fuse into windows.”

To this end, the nozzles of the new 3-D printing system can be adapted to vary the density of the material being poured, and even to mix different materials as it goes along. In the version used in the initial tests, the device created an insulating foam shell that would be left in place after the concrete is poured; interior and exterior finish materials could be applied directly to that foam surface.

The system can even create complex shapes and overhangs, which the team demonstrated by including a wide, built-in bench in their prototype dome. Any needed wiring and plumbing can be inserted into the mold before the concrete is poured, providing a finished wall structure all at once. It can also incorporate data about the site collected during the process, using built-in sensors for temperature, light, and other parameters to make adjustments to the structure as it is built.

Keating says the team’s analysis shows that such construction methods could produce a structure faster and less expensively than present methods can, and would also be much safer. (The construction industry is one of the most dangerous occupations, and this system requires less hands-on work.) In addition, because shapes and thicknesses can be optimized for what is needed structurally, rather than having to match what’s available in premade lumber and other materials, the total amount of material needed could be reduced.

While the platform represents an engineering advance, Oxman notes. “Making it faster, better, and cheaper is one thing. But the ability to design and digitally fabricate multifunctional structures in a single build embodies a shift from the machine age to the biological age — from considering the building as a machine to live in, made of standardized parts, to the building as an organism, which is computationally grown, additively manufactured, and possibly biologically augmented.”

“So to me it’s not merely a printer,” she says, “but an entirely new way of thinking about making, that facilitates a paradigm shift in the area of digital fabrication, but also for architectural design. … Our system points to a future vision of digital construction that enables new possibilities on our planet and beyond.”

Source : Massachusetts Institute of Technology

NASA Spacecraft Dives Between Saturn and Its Rings

Scienceadaily.com - NASA's Cassini spacecraft is back in contact with Earth after its successful first-ever dive through the narrow gap between the planet Saturn and its rings on April 26, 2017. The spacecraft is in the process of beaming back science and engineering data collected during its passage, via NASA's Deep Space Network Goldstone Complex in California's Mojave Desert. The DSN acquired Cassini's signal at 11:56 p.m. PDT on April 26, 2017 (2:56 a.m. EDT on April 27) and data began flowing at 12:01 a.m. PDT (3:01 a.m. EDT) on April 27.

"In the grandest tradition of exploration, NASA's Cassini spacecraft has once again blazed a trail, showing us new wonders and demonstrating where our curiosity can take us if we dare," said Jim Green, director of the Planetary Science Division at NASA Headquarters in Washington.

This unprocessed image shows features in Saturn's atmosphere from closer than ever before. The view was captured by NASA's Cassini spacecraft during its first Grand Finale dive past the planet on April 26, 2017. Credit: NASA/JPL-Caltech/Space Science Institute 

As it dove through the gap, Cassini came within about 1,900 miles (3,000 kilometers) of Saturn's cloud tops (where the air pressure is 1 bar -- comparable to the atmospheric pressure of Earth at sea level) and within about 200 miles (300 kilometers) of the innermost visible edge of the rings.

While mission managers were confident Cassini would pass through the gap successfully, they took extra precautions with this first dive, as the region had never been explored.

"No spacecraft has ever been this close to Saturn before. We could only rely on predictions, based on our experience with Saturn's other rings, of what we thought this gap between the rings and Saturn would be like," said Cassini Project Manager Earl Maize of NASA's Jet Propulsion Laboratory in Pasadena, California. "I am delighted to report that Cassini shot through the gap just as we planned and has come out the other side in excellent shape."

The gap between the rings and the top of Saturn's atmosphere is about 1,500 miles (2,000 kilometers) wide. The best models for the region suggested that if there were ring particles in the area where Cassini crossed the ring plane, they would be tiny, on the scale of smoke particles. The spacecraft zipped through this region at speeds of about 77,000 mph (124,000 kph) relative to the planet, so small particles hitting a sensitive area could potentially have disabled the spacecraft.

As a protective measure, the spacecraft used its large, dish-shaped high-gain antenna (13 feet or 4 meters across) as a shield, orienting it in the direction of oncoming ring particles. This meant that the spacecraft was out of contact with Earth during the ring-plane crossing, which took place at 2 a.m. PDT (5 a.m. EDT) on April 26. Cassini was programmed to collect science data while close to the planet and turn toward Earth to make contact about 20 hours after the crossing.

Cassini's next dive through the gap is scheduled for May 2.

Launched in 1997, Cassini arrived at Saturn in 2004. Following its last close flyby of the large moon Titan on April 21 PDT (April 22 EDT), Cassini began what mission planners are calling its "Grand Finale." During this final chapter, Cassini loops Saturn approximately once per week, making a total of 22 dives between the rings and the planet. Data from this first dive will help engineers understand if and how they will need to protect the spacecraft on its future ring-plane crossings. The spacecraft is on a trajectory that will eventually plunge into Saturn's atmosphere -- and end Cassini's mission -- on Sept. 15, 2017.

More information about Cassini's Grand Finale, including images and video, is available at:

www.saturn.jpl.nasa.gov/grandfinale

The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. JPL, a division of Caltech in Pasadena, California, manages the mission for NASA's Science Mission Directorate. JPL designed, developed and assembled the Cassini orbiter.

More information about Cassini is at:

www.nasa.gov/cassini
www.saturn.jpl.nasa.gov

Source : NASA/Jet Propulsion Laboratory