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  • richardmitnick 3:50 pm on November 20, 2014 Permalink | Reply
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    From NOVA: “Does Antimatter Fall Up or Down?” 

    PBS NOVA

    NOVA

    Wed, 19 Nov 2014
    Matthew Francis

    There are two kinds of matter in the universe: ordinary matter, which makes up all the stuff of everyday life, and antimatter, a sort of mirror image of matter. When the two meet, they annihilate in a flash of energy. It’s our good fortune that, in the early Universe, there was just a tiny bit more matter than antimatter, leaving us with a cosmos almost empty of stuff that could destroy us. Otherwise, we wouldn’t be here to ask what, exactly, antimatter is.

    Here’s what we know: Anti-electrons, known as positrons, are nearly identical to electrons, but instead of being negatively charged they are positively charged. The same goes for other antimatter counterparts: antiprotons are negatively charged and made of the antiquarks corresponding to the quarks in normal protons.

    But physicists think that the other properties of the particles should be the same. Each antimatter particle should have the same mass, spin, and equal but opposite electric charge, and other important properties. But that “should” hides something interesting: In some cases, we simply don’t know the fundamental properties of an antiparticle, because it’s much harder to experiment on antimatter than on matter. For example, it’s possible antimatter doesn’t feel gravity in the same way matter does.

    In other words, antimatter might fall up.

    b
    Up, up and away. Credit: Flickr user Shaun Fisher, adapted under a Creative Commons license.

    Now, that’s a very unlikely possibility. As far as we can tell, the differences between matter and antimatter are confined to interactions involving the weak nuclear force, one of the four fundamental interactions in nature. “Everybody including us would be shocked if we were actually to discover any significant differences” between matter and antimatter, says Joel Fajans, physics professor at the University of California at Berkeley who is studying how gravity affects antimatter. It may be a long shot, but if any experiment showed measurably different behavior, “it would really revolutionize our thinking about how the universe behaves.”

    The effort isn’t easy, though. First, there’s a lot more matter than antimatter in the universe, so any differences in behavior would be very difficult to observe and measure. Second, experiments must be done quickly, before antimatter runs into ordinary matter and everything goes kablooie.

    As a result, we only have rough estimates of some basic properties of antimatter—and some we haven’t measured experimentally at all. Take, for instance, a fundamental quantity called the positron inertial mass, a measure of how difficult it is to accelerate a positron. (The inertial mass is the “m” in E = mc2.) When an electron meets a positron and they annihilate, they give off gamma rays. Researchers can measure the spectrum of gamma rays and figure out how much m was needed to make the E they see. From that, physicists have concluded that the inertial mass of the electron and the positron are very close to equal, if not identical.

    We’d like to do better than “very close,” though. To understand antimatter fully, we need measurements as precise and accurate as our measurements of matter, and that’s a hard goal. Similarly, we don’t yet have precision measurements for the electric charge of the positron and the antiproton, though Fajans and his collaborators have shown that their charges are equal and opposite. This experiment, like many modern antimatter tests, involves atoms of antihydrogen, which are made of a single antiproton and positron. To see if antimatter falls up, Fajans and his colleagues at the ALPHA experiment use strong magnetic fields to trap antihydrogen atoms in a sort of virtual bottle.

    CERN ALPHA New
    ALPHA at CERN

    “If we very slowly turn off the ‘walls,’ the magnetic confining field, [the antihydrogen atoms] eventually get out,” Fajans says. “If we do it slowly enough, even though the effects for gravity are subtle, there’ll be a tendency for them to fall downwards presumably, or upwards if things really are weird.” So far, the results aren’t precise enough to distinguish between falling up and falling down, but that’s merely a sign of how inherently difficult the experiment is.

    However, there’s strong indirect evidence that antimatter behaves gravitationally like matter. According to the weak equivalence principle—a key part of the general theory of relativity [Albert Einstein]—the gravitational mass is precisely the same as inertial mass,. (The strong equivalence principle relates to the mathematical structure of gravitational theory.) Researchers have tested the weak equivalence principle to high precision for ordinary matter, using delicate balances capable of detecting tiny variations in gravitational attraction.

    While we can’t yet make the same lab equipment out of anti-atoms to test the weak equivalence principle for antimatter, we know that protons and neutrons contain “virtual” pairs of quarks and antiquarks, which don’t have independent existence but contribute to the particles’ overall structure. As Fajans points out, “Different isotopes have different ratios of virtual antimatter particles, and it’s very well known that there are no anomalies there. If virtual antimatter particles gravitate differently, that would have been noticed in all of these experiments.”

    There are also theoretical reasons to suspect gravity doesn’t work in reverse for antimatter. Raquel Ribeiro, a physicist at Case Western Reserve University, works on possible modifications to general relativity that could solve the riddle of cosmic acceleration. But Ribeiro doesn’t include antigravity antimatter, “because it leads to a number of physical violations of energy principles,” she says. While naively all it would take is turning mass from a positive into a negative number, the reality for stars and other astronomical bodies would be “some serious instabilities in the system.”

    Theory is a good guide, but we still need experiments to see if our theories are right or if they need modification. In fact, theory is so far unable to solve one of the deepest mysteries in physics. “There simply isn’t enough antimatter in the universe,” says Fajans, “and there isn’t a universally accepted reason as to why matter in the universe predominates by such a large ratio over antimatter. The Big Bang should have created exactly equal amounts of matter and antimatter.”

    That’s one reason why researchers will keep studying antimatter, and why some hold out hope for finding even small differences in the behavior of matter and antimatter. Maybe we won’t see antihydrogen falling up, but even a subtle deviation from expectations could open up a new world of possibilities. After all, that’s what the initial discovery of antimatter did.

    See the full article here.

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  • richardmitnick 3:28 pm on November 14, 2014 Permalink | Reply
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    From NOVA: “Does Science Education Need A Civic Engagement Makeover?” 

    PBS NOVA

    NOVA

    12 Nov 2014
    Brooke Havlik

    Even though the political campaign signs have been brought inside following Election Day, social studies and government classrooms will continue to discuss civics throughout the school year. According to the National Council for Social Studies, the goal of social studies is to promote civic competence, or the knowledge and intellectual skills to be active participants in public life. Yet, engaging with the most complex public issues of our time—biodiversity, climate change, water scarcity, obesity, energy, and HIV/AIDS—also requires a deep understanding of the scientific process.

    dots
    Students connect the dots between their daily lives and climate change.

    While the economic argument for doing a better job preparing American students with 21st century skills in STEM has been made time and time again, teaching students what philosopher John Dewey called “the scientific habit of the mind,” also has broader benefits for society. The more students are able to connect the dots between scientific processes and science’s impact on society, the more informed their political decisions will be as adult citizens.

    Dr. Ricky Stern of “e” inc., a Boston-based environmental science program that educates hundreds of students each year, believes civic engagement and science education are a natural fit given the many challenges our planet faces. “Civic engagement tells urban youth there are real steps and genuine actions available to them and that rather than watch the events of the day from a distance, instead come in and join in. Come be part of a larger program—of something bigger than just yourself.”

    Bringing social issues into science classrooms may also open up more STEM career possibilities for youth. In 2012, Net Impact and Rutgers University partnered to find out what college Millennials (21-32 years old) look for in their careers. Over 70 percent of college Millennials surveyed responded that it was very important to secure a job that makes a difference, and 31 percent found it “essential.” This is higher than 49 percent of Generation X (33-48 years old) and 52 percent of Baby Boomers (49-65 years old) who found “making a difference” to be important to their career choices. Many of today’s youth grow up connecting the concept of “making a difference” to careers in social work, public health and education. While these are all worthwhile fields, careers in disciplines such as computer science, biotechnology or engineering rarely make the list, despite their strong potential to improve society through science.

    copy
    Dr. Stern believes, “Engagement is important as it signals to children or teens that they are needed or central to making things better.”

    So, what would more civic engagement look like in a science classroom? Every community, school, and educator may have a different approach. Here are three methods and examples of ways to help students participate in civic and socio-scientific conversations.

    Explore answers together

    Alex Miller, a teacher at Village Leadership Academy recently began conversations in her science classroom about the Tuskegee syphilis experiment, an infamous U.S. government study between 1932 and 1972 of rural African American men. Ms. Miller’s goal was to help her students see the connections between science and social justice. She brought in articles about the research and facilitated a conversation about the study’s implications. Ms. Miller knew she didn’t have all the answers for them. Instead of lecturing, she actively explored the history alongside her students and allowed space for them to explore science’s role in the problem. Consequently, she helped her students think deeply about bioethics.
    Make it normal to follow current science events

    Devote time to talking about science news during every class. If you are crunched for time to read it in class, provide students the story’s summary and facilitate a short discussion about the social or political implications. For example, in a recent story from NOVA Next, scientists developed a tool called CRISPR-Cas9 to control mosquito populations through genetic modification. The technique has the potential to control or eradicate malaria. Ask students how this new technology benefits society. What could be some negatives? Do the benefits outweigh the negatives? Give students more responsibility by asking them to pick articles and lead the conversation.
    Offer opportunities for project-based learning with a civic goal

    Dr. Stern mentioned that, “We teach science lessons every week to many children and teens. As they get more involved with the science ideas, simultaneously, we also begin to teach them that there are some related challenges on the planet going on right now.” After talking with students about what project and action they want to take on, students “pick a team project based on what they have learned and they maintain it for the year.”

    feet
    Pick a project devoted to a socio-scientific issue students care about and encourage them to take action on it throughout the year.

    Examples of project-based civic engagement might include recording and reducing school energy consumption, starting a compost program or educating other students and staff on a public health issue. Students can present orally to the class at the end of the year, and use scientific concepts to back up why their project matters.

    There is no doubt that science can have wider appeal by building opportunities for active civic engagement inside and outside the classroom. Are you already bringing civic engagement into your science classroom? NOVA would like to hear about it. Send your story to NOVAeducation@wgbh.org.

    Image Credits: T.E.J.A.S. Healthy Manchester Festival / Flickr CC-BY-NC-ND, 350.org /Flickr CC BY-NC-SA, Penn State / Flickr CC BY NC ND [this is a poor way to provide image credits. I am surprised at this NOVA blog for doing this.

    See the full article here.

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  • richardmitnick 3:09 pm on November 14, 2014 Permalink | Reply
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    From NOVA: “For Every 1°C of Global Warming, Lightning Strikes Will Increase By 12%” 

    PBS NOVA

    NOVA

    13 Nov 2014
    Allison Eck

    In the not-too-distant future, as the Earth warms, the heat energy that churns our atmosphere could spark even more lightning than the 8 million that strike today.

    A new study published today in the journal Science suggests that we’ll see 12% more strikes for every 1˚ C of warming. Earlier models used cloud depth to determine how likely they were to generate enough energy to produce a lightning bolt. But climate scientist David Romps and his colleagues instead looked at precipitation, humidity, and temperature measurements taken from weather balloons. Put together, this data indicates how energetic an impending storm could be, and in turn, how probable it is that lightning bolts will streak through the sky.

    light
    Scientists project that lightning strikes could significantly increase in frequency by the turn of the next century.

    Here’s Andy Coghlan, writing for New Scientist:

    By knowing how much water is in the clouds and how much energy is available, Romps says his model can accurately predict how many lightning bolts will get generated. Typically, he says, about 1 per cent of the potential energy picked up by water gets converted to lightning, so by knowing how much water and energy is present, the team can work out how much lightning will form.

    They tested the model using real weather data from 2011, and compared the results with the data on every lightning strike in the US, collected by the National Lightning Detection Network. In simple terms, they found that it retrospectively correctly accounted for 77 per cent of that year’s ground strikes. “When I saw that result, I thought it was too good to be true,” says Romps.

    Romps and his team then applied their lightning model to 11 different climate models. In Romps’ model, lightning varies consistently with temperature and energy. Using that same math, he calculated the percent increase for every 1° C rise in global temperatures. At the extremes, some model runs even suggested that strikes could double by the year 2100.

    The team doesn’t know yet whether these strikes will cluster in particular areas, but one thing is for sure: increased bolts to the Earth’s surface means greater chance of wildfires and a shift in the chemical composition of the atmosphere.

    Here’s Victoria Gill, writing for BBC News:

    As well as triggering half of the wildfires in the U.S., each lightning strike—a powerful electrical discharge—sparks a chemical reaction that produces a “puff” of greenhouse gases called nitrogen oxides.

    “Lightning is the dominant source of nitrogen oxides in the middle and upper troposphere,” said Prof. Romps.

    And by controlling this gas, it indirectly regulates other greenhouse gases including ozone and methane.

    The result could be a vicious cycle: rising temperatures cause an increase in lightning strikes, thereby releasing into the atmosphere gases that perpetuate Earth’s warming even further.

    Of course, Romps’ model isn’t perfect—it doesn’t yet account for the fact that parts of the globe experience very little rainfall, nor does it factor in lightning strikes that don’t make it to the ground. The precipitation measurements could be made clearer, too. Right now, the model measures clouds’ water content and not its additional ice content. Nevertheless, it seems likely that someday soon, lightning will be even more prevalent than it is today.

    Experts aren’t sure what triggers lightning, but suspect it could be cosmic rays from outer space.

    See the full article, with video, here.

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  • richardmitnick 7:49 pm on November 13, 2014 Permalink | Reply
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    From NOVA: “There’s More Than One Way To Hunt For Gravitational Waves” 

    PBS NOVA

    NOVA
    Part 1
    Physicists are poised to make the first-ever direct detection of gravitational waves. Will the detection come from a big-budget experiment already a decade deep into the search? Or will one of a handful of dark-horse experiments win an upset?

    When Albert Einstein published his general theory of relativity in 1916, he revolutionized physics and reenvisioned the nature of spacetime and gravity: he showed that spacetime was dynamic, not static, and reimagined gravity as the bending and warping of spacetime by massive objects. He also made the startling prediction that gravity travels in waves. Just as objects moving through water cause waves to ripple outward, objects moving through space should produce ripples in spacetime. The more massive the object, the more it will churn the surrounding spacetime, and the stronger the gravitational waves it should produce.

    i
    Gravitational waves from two merging black holes, as simulated by a supercomputer model at NASA’s Ames Research Center. Credit: Henze, NASA

    Most of these ripples would be small, and would dissipate too quickly to be detected, Einstein predicted. But certain bodies, such as merging black holes, supernovae, or orbiting pairs of neutron stars, are massive enough that they might produce detectable gravitational waves. Physicists have devised a number of ingenious methods to detect gravitational waves directly, from extremely precise laser interferometry to clever schemes for using stars, pulsars, even the Earth and moon as gravitational wave detectors.

    The big-ticket project is the half-a-billion-dollar Laser Interferometer Gravitational Wave Observatory (LIGO), which boasts two highly sensitive laser interferometers in Louisiana and Washington state. Here’s how it works: Split a laser beam in two and send each beam down one of two long, perpendicular tunnels, each with a mirror at the end. When the laser beams strike the mirrors they will be reflected back to the same spot, where they will recombine and cancel each other out. But if a gravitational wave happens to be passing through, it will warp the space between those mirrors ever so slightly. One beam will travel a longer path than the other, and when they meet up again, they won’t cancel each other out, producing light that will be picked up by a detector.

    LIGO ran from 2002 to 2010—almost a decade—yet failed to detect any gravitational waves. Furthermore, LIGO is sensitive only to a small fraction of the gravitational wave spectrum. Just as optical, radio, x-ray, infrared, and gamma-ray telescopes each reveal different, and complementary, electromagnetic views of the cosmos, says Montana State University physicist Neil Cornish, it will take more than one kind of gravitational wave telescope to “see” the full gravitational wave spectrum. “You can only see [the waves] in their particular [frequency] bands because the frequency they emit is set by the mass of the system,” Cornish explained in an interview. “We need to open up the entire gravitational wave spectrum just like we’ve opened up the entire electromagnetic spectrum [in astronomy].”

    LIGO’s range centers on stellar remnant black holes and other celestial objects of similar mass. Tackling the lowest end of the gravitational wave frequency spectrum are the headline-grabbing BICEP2 and Planck experiments, which are looking for imprints left by gravitational waves from the earliest moments of our universe in the polarization of the cosmic microwave background radiation.

    Cosmic Background Radiation Planck
    CMB per ESA/Planck

    To detect higher-frequency gravitational waves, like those produced by supermassive black holes, astronomers are using pulsars—rapidly rotating neutron stars that beam out regular radio pulses—like beacons on the sloshing sea of spacetime. One such effort is the North American Nanohertz Observatory for Gravitational Waves (NanoGRAV) , part of an international consortium that also includes the European Pulsar Timing Array, and the Parkes Pulsar Timing Array in Australia.

    The first pulsar was discovered in 1967, when Jocelyn Bell Burnell and Antony Hewish noticed strange, highly regular radio pulses coming from a fixed point in the night sky. They cheekily dubbed the mysterious object LGM-1 (for “little green men”). The signals weren’t coming from alien transmissions, however, but from a rapidly rotating neutron star. Pulsars form when stars more massive than our Sun explode and collapse into neutron stars. As they shrink, they spin faster and faster, because angular momentum is conserved. (Think of what happens when you swing an object around your head on a string: the more you shorten the tether, the faster it goes.) Pulsars also blast out radiation that can be picked up on Earth whenever that beam sweeps into our direction, like the rotating beam of a lighthouse.

    The fastest pulsars, spinning hundreds of times per second, make excellent clocks—on par with the best atomic clocks. “That regular rotation of a pulsar is like the swing of a pendulum,” said Cornish, and it enables astrophysicists to precisely time all kinds of astronomical systems. Pulsars have helped astronomers identify distant exoplanets, and provided the first indirect evidence for gravitational waves back in 1982, when astronomers observed energy leaking out of a binary pulsar system—probably in the form of gravitational radiation.

    The NanoGRAV network uses data from telescopes at the Arecibo Osbervatory in Puerto Rico and the Green Bank Telescope in West Virgina to monitor 19 pulsars in the Milky Way that serve as a galactic-scale gravitational wave detector. The method is described on NanoGRAV’s Website as a “cosmic Global Positioning System… looking for tiny changes in the position of the Earth that are due to the shrinking and stretching effect of passing gravitational waves,” although Cornish said the analogy is imperfect. The GPS employs multiple satellites to triangulate the three dimensions of space, thereby pinpointing the location of the source of a signal. NanoGRAV is looking for a common effect in the form of a telltale signature: a “shimmering” effect produced because pulses affected by gravitational waves should arrive slightly earlier or later in response to those ripples in spacetime. While no detection has yet been made, the collaborators are currently combining data from all three arrays to further improve accuracy and precision, according to Cornish. Those results should be released in the next several months.

    Arecibo Observatory
    Arecibo Observatory

    NRAO GBT
    NRAO/Green Bank Telescope

    “Compared to the cost of LIGO, this is the bargain basement way of detecting gravitational waves,” says Cornish. “The NSF has made this major investment using laser interferometers. For a tiny fraction of that, they have a chance to enable detection using pulsar timing. As far as bang for buck, it’s the cheapest way to go about it.”

    Part 2
    All of these techniques are exquisitely sensitive, seeking out minute changes. But gravitational waves might have a much stronger impact on matter than previously assumed, thanks to resonant frequencies. It’s something Alexander Graham Bell noticed as a young man: strike a chord on one piano and it will be echoed by a piano in another room. The effect is known as “sympathetic resonance.” Objects like a piano’s strings vibrate at very specific frequencies. If there is another object nearby that is sensitive to the same frequency, it will absorb the vibrations (sound waves) emanated from the other object and start to vibrate in response.

    pi
    Strike a chord on one piano and it will be echoed by a piano in another room. Physicists have proposed using a similar resonance phenomenon to detect gravitational waves. Credit: Flickr user Half Full Photography, adapted under a Creative Commons license.

    That’s the essence of a new paper in the Monthly Notices of the Royal Astronomical Society: Letters, proposing that certain stars could absorb energy from gravitational waves that ripple by. Should that happen, the stars would show a temporary marked increase in brightness from that excess energy that could be measurable.

    Co-author Saavik Ford of CUNY’s Graduate Center compared stars to the bars on a xylophone, each of which has a natural resonant frequency, just like piano strings. Striking those bars in sequence, moving from lower to higher frequencies, is akin to how two merging black holes produce gravitational waves of gradually increasing frequency. “If you have two black holes merging with each other and emitting gravitational waves at a certain frequency, you’re only going to hit one of the bars on the xylophone at a time,” Ford explained. “But because the black holes decay as they come closer together, the frequency of the gravitational waves changes and you’ll hit a sequence of notes. So you’ll likely see the big stars lighting up first followed by smaller and smaller ones.”

    Perhaps the Earth itself could be used as a gravitational wave detector: it, too, could vibrate like a bell in response to gravitational waves rippling through. Set up a global array of highly sensitive seismometers, and one could conceivably find evidence of such waves in the data That was the gist of a 1969 paper by physicist Freeman Dyson.

    Dyson’s work was the inspiration for Harvard graduate student Michael Coughlin and a colleague, Jan Harms of the National Institute of Nuclear Physics in Florence, Italy, who were working with seismic data relating to LIGO with an eye toward reducing the noisy background so that a signal would be more easily detected. Coughlin recalled Dyson’s paper and thought such an approach could be useful for setting some vital constraints on background noise, and he and Harms did an initial analysis of terrestrial seismic data.

    Then another professor recalled his earlier geophysical work with instruments placed on the moon during the Apollo missions to track so-called “moonquakes.” Those instruments collected lunar seismic data from July 1975 to March 1977. Intrigued, Coughlin and Harms analyzed that older dataset as well, correlating it with their earlier terrestrial analysis. They published their findings in Physical Review Letters earlier this year.

    Coughlin and Harms didn’t find any evidence of gravitational waves in their analysis, nor did they expect to. One reason is that there is a lot of seismic noise from other sources cluttering up the data. The moon might not have Earth’s plate tectonics, atmospheric fluctuations, or volcanic activity, but asteroids routinely hit the moon, causing it to “ring” for weeks from the impact. There is also background noise generated by thermal heating from the Sun and tidal forces.

    Cornish pronounced their work a good analysis but said it is unlikely to lead to direct detection of gravitational waves, even if NASA placed upgraded seismometers on the moon with far greater sensitivity to get a better dataset. He suggested that the best way to search for gravitational waves in that frequency range is the space-based LISA, now known as the Next Gravitational-wave Observatory (NGO), another very large and pricey collaboration similar to LIGO (in that it uses a similar laser interferometer array) that is still several years’ away from completion. Meanwhile, LIGO is currently undergoing upgrades, including an additional mirror to increase its sensitivity to other frequencies of gravitational waves, like those produced by binary pulsars.

    Still, there remains much uncertainty in the various proposed models for gravitational waves. Coughlin’s and Harms’ null result has helped further constrain the range in which we should expect to see gravitational waves in Earth’s vicinity. “If we thought we knew what the source distribution of gravitational waves looked like in the universe, then it wouldn’t be quite such a useful exercise,” Coughlin said. “Since we don’t, and the cost is relatively low, I don’t see why we shouldn’t try it.”

    See the full article here, for Part 1 and here for part 2

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  • richardmitnick 5:33 am on November 12, 2014 Permalink | Reply
    Tags: , , , Food research, NOVA   

    From NOVA: “The Next Green Revolution May Rely on Microbes” 

    PBS NOVA

    NOVA

    12 Jun 2014
    Cynthia Graber

    Ian Sanders wants to feed the world. A soft-spoken Brit, Sanders studies fungus genetics in a lab at the University of Lausanne in Switzerland. But fear not, he’s not on a mad-scientist quest to get the world to eat protein pastes made from ground-up fungi. Still, he believes—he’s sure—that these microbes will be critical to meeting the world’s future food needs.

    Sanders’s eyes widen with delight and almost childlike glee when he talks about a microscopic life form called mycorrhizal fungus, his chosen lifetime research subject. Mycorrhizal fungi live in a tightly wound, mutually beneficial embrace with most plants on the planet. Years of dedication have made Sanders into one of the world’s foremost experts on the genetics of the microbe, and he recently was part of a team that sequenced the first mycorrhizal fungi genome.

    mz
    Mycorrhizal fungi colonize the tip of a root, seen here under magnification.

    Despite his drive, Sanders comes across as light-hearted as he teases and jokes with fellow researchers. But he loses his affable smile as he fires off facts about the upcoming food shortage: The world’s population is expected to increase to between 9 billion and 16 billion people. Five million people per year die of direct causes of malnutrition. Three and a half million of those are children under five. Today, we have the means to grow enough food to feed all those people, but we will most certainly need to produce more in the very near future.

    Sanders may have come up with a way to do just that. He has successfully bred custom varieties of microbes that can help plants produce more food. It’s one of the ultimate goals of farming research—more food with, he hopes, little or no environmental downside.

    We’ve been looking at the wrong set of genes.

    The question of crop productivity is increasingly fraught. People in developed countries eat an enormous amount of food, and people in developing countries are beginning to close the gap. Meanwhile, the world’s population is swelling. By 2030, the UN’s Food and Agriculture Organization predicts food demand will soar by 35%. And then there’s the accelerating impact of climate change: The IPCC’s latest report on the subject, published in March, shows that scientists are predicting a 2% decrease in crop yields per decade over the next century. Higher temperatures and longer, more dramatic swings between drought and rain mean the plants that we rely on will have a hard time weathering the strain.

    According to the FAO, most of the growth in production that we’ll need has to come from increasing yields from crop plants. Selective breeding doesn’t seem to be offering the types of dramatic yield increases seen in the past. Meanwhile, genetic engineering has yet to lead to any significant increase in yields.

    Now, many scientists are saying that we’ve been looking at the wrong set of genes. Instead of in plants, the crucial genes may reside in the galaxy of bacteria and fungi that live in the soil and throughout a plant—the kind that Sanders studies.

    Sanders’ plan is to give existing fungi-plant relationships a boost by breeding better fungi. He’s testing varieties of lab-grown microbes out in the field in tropical Colombia. There, he’s hoping to help cassava plants grow heftier roots, as these potato-like crops are a staple for nearly a billion people around the world. So far, the results show that this approach just might work.

    Belowground Microbiome

    Microbes in the soil function much like the human microbiome, which helps us break down food, access nutrients, and defend against harmful invaders. A plant’s microbiome protects it against malevolent microbes. Microbes can also communicate with one another, flashing chemical alerts that let one plant know when another nearby is under attack. Bacteria and fungi even structure the soil so that it clumps together and doesn’t blow or wash away. And, just as our human cells are outnumbered by our microbial support, the microbial genes in and near the root system alone of a healthy plant greatly eclipse those of the plant itself.

    Plants have depended on microbial assistance since they first edged out of the water onto dry land, about 450 million years ago. They lassoed photosynthetic cyanobacteria and turned them into cellular machines known as chloroplasts, which harvest the sun’s energy. Today, plants are still supported by hundreds of thousands—perhaps millions—of different species of bacteria, fungi, even viruses. In fact, the rhizosphere, the area around a plant’s roots, is considered one of the most ecologically diverse regions on the planet.

    The microbiome in the rhizosphere acts as an extension of plants’ root systems, breaking down nutrients into forms that plants can use. Mycorrhizal fungi have whisper-thin fronds, called hyphae, that reach out past the root tips to access water and nutrients the plant needs to survive. They then trade those for carbohydrates the plant provides. Scientists believe that as much as 30% of the carbon that a plant produces through photosynthesis is pushed into the soil to support an entire city of microbes.

    Though mycorrhizal fungi are just a multitude microbe species in the soil in and around plant roots, they live in symbiosis with about 80–90% of agricultural crops in a relationship hundreds of millions of years old. Mycorrhizal fungi cannot survive without plants, and most plants cannot thrive without mycorrhizal fungi.
    As much as 30% of the carbon that a plant produces supports an entire city of microbes.

    On the most basic level, scientists have known that microbes associate with plants for more than a century, but, even today, many of the details of the interactions are still unknown. Part of the challenge in teasing them out is that they’ve been nearly impossible to study. Scientists estimate that perhaps 1% of all soil microbes can be grown on a petri dish, the conventional model for such research. By only being able to study the thinnest slice of life, we’ve been missing out on a vast, complicated, messy world. It’s like trying to guess what everyone on a city block does during the day by trailing just one person.

    Recently, though, scientists have begun to get a better glimpse. Genetic analyses can help classify and understand newly discovered microbes. Big Data-style techniques, with names like metagenomics, proteomics, and transcriptomics, describe methods by which scientists can take an overall picture of the genetic diversity of life in a given region, and even what genes are active. These types of studies might not be able to describe every individual, but they can give a sense of what genes are in play. Such tools are able to do more, do it more quickly, and do it for less money nearly every year.

    In only the last few years, scientists using these tools have begun to regularly uncover new information about the crucial links between microbes and plants. They’re unraveling clues as to which bacteria, fungus, or virus performs which function. They’re discovering microbes that can help plants withstand heat and drought. And they’re dialing into the genetics to understand how the microbes do what they do, how the plants react, and even what genetic material is exchanged. There’s still a world of research to be done, however. With many millions of individuals packed into every gram of soil, it’s a daunting task.
    tending-cassava-field

    ka
    Tending a cassava field in the Amazon

    Farmers have manipulated the plant-microbe relationship, unknowingly, for thousands of years. Compost, for example, does not simply contain beneficial nutrients—it also teems with living organisms, as does animal manure. Crop rotation, too, can enhance microbial diversity. Stalks and crop remains left on the field or plowed into soil provide microbes with food. And growing particular plants together—such as the traditional grouping of bean-squash-corn in the early Americas—does the same, as each plant likely contributes a complementary set of microbes.

    But, for the most part, the tightly braided relationship hasn’t yet factored into the workings of modern agriculture. Today, if a plant needs more of anything, we just add it—water, nitrogen, phosphorus, manganese, and so on. In the 20th century, this approach produced an abundance of crops and staved off starvation for millions. But it has also soaked groundwater with nitrogen, led to algal blooms in lakes and rivers, and spawned a massive dead zone in the Gulf of Mexico. Studies show that nitrogen fertilizers can also reduce the diversity of microbial life. Pesticides can be more harmful. Even tilling cleaves fungal networks. Until recently, we knew little about how we’ve been inadvertently crippling our crops’ complicated support network.

    “Over the last hundred years in agriculture, we’ve tried to take microorganisms out of the picture. And by doing that—by disrupting the soil with tillage, by using chemical pesticides—we have greatly altered the agricultural biome,” says Rusty Rodriguez, a former microbiologist with the U.S. Geological Survey who’s now head of Adaptive Symbiotic Technologies, a company developing microbial-based seed coatings. “The efficacy of many chemicals is beginning to wane.” Bacteria and fungi, Rodriguez says, “are the next paradigm for agriculture.”
    From Switzerland to Columbia

    Sanders’ Swiss workplace is immaculately clean, and the room where the fungi are taken out for study is scrupulously sterile. Every night, all night, UV lights shine a microbe-killing glare. They destroy anything that could infect his cultures of mycorrhizal fungi.

    Over the course of Sanders’ 26-year career, he’s made a number of key discoveries about fungi genetics and reproduction. He conducted early research that demonstrated that the greater the diversity of mycorrhizal fungi in a given ecosystem, the greater the diversity of plants. And in 2008, as he delved into genetics, he proved that they don’t just reproduce by cloning—they actually exchange genetic material, both in the lab and in the field.

    This gave him an idea. If the microbes created offspring that were different from one another, Sanders thought, “you have a good chance that some will be more effective on plant growth than others.” So he came up with a plan: Take different fungi, breed them, see if any help plants out more than others. In other words, take the approach to farming that breeders have used for thousands of years and use it on fungi.
    Without human intervention, the whole system of microbial support might not be optimally tweaked to match crossbred crops.

    This is where Sanders runs into occasional criticism from some of his microbe-studying colleagues, who say that nature has already bred all the best variety of microbes. “If you use the argument from these researchers,” he counters, “then no one would have produced any plants through plant breeding, because they would have said, ‘Well, nature’s already made the best plants, and we can’t make any more that are any better than what nature has made.’ Now, of course, we know from a few thousand years of agriculture that we can make plants better by crossing them, and we can get varieties that produce bigger yields than that which we see in natural-occurring varieties of those plants in nature.” Without similar human intervention, the whole system of microbial support might not be optimally tweaked to match.

    To test out his idea, Sanders partnered with a colleague in Switzerland who was studying the genetics of the fungi-rice relationship, and who already had conducted research in a university greenhouse set up for rice cultivation. Sanders grew the fungi and allowed them to exchange genetic material and reproduce, creating genetically distinct offspring. Then, he colonized rice with these distinct lines. Sanders used rice as a matter of convenience due to his colleague’s experience, but he also knew that rice, as farmed today, tends to actually grow more poorly when inoculated with mycorrhizal fungi, making it a good test bed. He was stunned when one of the lines produced a five-fold increase in growth over the other fungal lines. “To see such a huge growth increase was very, very surprising,” he says. The greenhouse was an artificial environment, and the microbe-enhanced soil was compared to sterile soil. It in no way mimicked nature. But it proved a point.

    Around that time, Sanders got back in touch with Alia Rodriguez, an agronomist in Colombia who also had expertise in mycorrhizal fungi. They had originally met when he was one of her PhD examiners in England. He was desperate to visit Colombia and see its amazing animal and plant biodiversity for himself, so they decided to try to find a research project together.

    It happened that Colombia offered the perfect field test for his new approach. Mycorrhizal fungi are skilled at helping plants access phosphorus, a key nutrient, which plants in tropical countries have a particular problem securing. The acidity of soil there results in a chemical reaction that ties up most of the phosphate that farmers add to soil. Farmers end up paying precious money to add phosphate that plants mostly can’t use. “I always tell my students, how can we rely on a practice that is so inefficient?” Rodriguez says. “It has to change, because it cannot be sustainable.”
    experimental-cassava-fields.

    fie
    Ian Sanders and Alia Rodriguez’s experimental plots in Columbia

    Colombia is also the home of cassava, a fleshy white root. Cassava is a major staple for nearly a billion people in more than 100 countries, from Brazil to Nigeria to Thailand, who rely on it in much the same way we rely on bread or potatoes. In its various homes and in various languages, it is called cassava, yuca, manioc, balinghoy, kamoteng kahoy, tapoica-root. If you can produce more cassava, then poor communities can eat more food.

    Sanders liked the idea of breeding microbes to increase cassava production. But they still had one major stumbling block ahead. There was no practical way to transport enough pure fungus from his Swiss lab to colonize the cassava trial fields in Colombia.

    This had also been a problem for the early pioneers in the field. In earlier decades, a variety of start-ups had marketed mycorrhizal fungi transported in soil, an imperfect medium that also contained plant roots and a host of other microbes. There was no way to tell whether it contained any live, viable material, let alone a specific species. Plus, transporting enough soil for every plant root on a farm would be heavy and prohibitively expensive.

    Fortunately for Sanders and Rodriguez, a company in Spain named Mycovitro coincidentally announced the culmination of decades of research of their own: a gel that could act as a vehicle for highly concentrated, purified mycorrhizal fungi. With the gel, Sanders would know that he was only transporting the microbes he wanted. A single small bottle could provide enough fungi for an entire field. Even more importantly, the gel base was capable of growing any variation that Sanders bred in his lab. The team partnered with Mycovitro to grow Sanders’ varieties. (The company has no financial connection to Sanders’ and Rodriguez’s research, and neither of the scientists have a stake in the company. The company, however, is providing its services for free, and it will have first right of refusal to commercialize any promising new line that Sanders and Rodriguez develop.)

    With the final piece in place, Sanders and Rodriguez set their research project in motion. They headed down to Columbia to test their varieties by growing hectares of cassava along the edge of the llanos, the country’s lush, damp tropical savannah.

    Catching On

    As the pieces of Sanders and Rodriguez’ research fell into place, the field of commercially-applicable bio products was undergoing a renaissance. A few decades ago, interest in microbes and their use in agriculture flared, but most of the commercial products quickly flickered out. Most of the laboratory successes hadn’t translated to the field. One of the few agricultural microbes that did catch hold was the bacterium Rhizobium, which helps legumes access nitrogen. It’s used extensively on crops such as soy. Other microbes, such as the bacterium Bacillus, are used to protect plants from pathogens. Rhizobium and Bacillus are not the only examples on the market, but the combined market share is still a small fraction of the multibillion dollar agro-chemical industry.

    But new, more effective products have begun to emerge. Marrone Bio Innovations’ most recent pesticide, called Grandevo, was developed from a soil bacterium and is marketed to protect vegetable crops from sucking insects and mites. The company, with more than 150 patents pending, has additional products in the pipeline, including a strain of Bacillus that both controls pathogens and encourages plant growth.

    Dozens of field trials in 14 states around the U.S. are testing microbial products for corn, soybeans, wheat, barley, and rice.

    Rusty Rodriguez (no relation to Alia Rodriguez in Colombia), the head of Adaptive Symbiotic Technologies, got his start in the 1990s when he and his colleagues discovered the symbiosis between plants and fungi in Yellowstone that allowed plants to survive in temperatures as high as 150˚ F. Once he identified and isolated the fungus responsible for the plant’s heat-survival ability, he realized he could use it to help other plants survive extreme heat.

    Rodriguez dove headfirst into extremophiles, sending company employees to collect plants from extreme environments around the U.S. He’s focusing on a number of products—some are single fungi, others are communities working together—that confer a variety of benefits to agricultural plants: drought tolerance, salt tolerance, and the ability to withstand swings in temperature. His company has developed tests that rule out any potential negative impacts of the strains, such as plant damage or toxicity to animals that might snack on them. They have dozens of field trials in place in 14 states around the U.S., working with farmers who are testing their products in corn, soybeans, wheat, barley, and rice.

    Farmers have been willing partners, Rodriguez says, happy to test products that might help what can be a razor thin profit margin. But, overall, the science of applying microbial products in agriculture has been hampered by one major challenge: moving from the lab to the field. “Field work is a lot more difficult to do,” says Rodriguez. “It fails way more often.”

    Sanders and Alia Rodriguez learned the same lesson in Colombia, when the floods came.

    To the llanos

    In Columbia, Sanders and Alia Rodriguez teamed up with an agricultural college named, appropriately, they hoped, Utopia. The professors and students served as field monitors for the crops and the research. Early one morning last July, the sun barely lifting off the flat green fields, I accompanied them and a group of students as they tromped out to visit their plants. Rodriguez poked fun at Sanders’ obsession with snapping photos: “We need to be moving on!” she nudged. “Yes, yes,” he muttered, bending down to focus his lens on a spider whose web spread across the spiny leaves of a pineapple plant.

    cas
    A graduate student tends cassava in an experimental plot.

    Finally we reached the experiment. The cassava looked nearly identical, all about three feet tall, creating a waist-high carpet of broad emerald leaves glittering with droplets misted from the low, grey sky. Despite the plants’ near uniform appearance, Sanders and Rodriguez knew that underground, where the fungi were going to work, the story would be different. There, they had expected to find roots of all sizes.

    The two scientists wandered out, half obscured by foliage: Rodriguez, with tight, dark ringlets woven into a long, single braid and tucked through the back of a salmon-colored baseball cap, and Sanders, whose pale skin clearly marked him as the outsider in the group. Isabel Ceballos, the Colombian PhD student managing the project, pulled a bright pink poncho over her head to ward off the rain.

    Each of the young cassava plants had started out as six-inch sticks. The team had laid them in the earth and covered them with a shallow layer of soil. Three weeks later, when the sticks started to form root buds, the students returned and carefully squeezed a layer of fungus-filled gel beneath a portion of each plant. As the roots stretched into the soil, they pushed down through the gel, inoculating them with mycorrhizae.

    That July day in Colombia, after checking the plants in the field, Sanders, Rodriguez, and I dragged plastic chairs together. They’d cleaned up from the morning’s mud. Rodriguez had changed into a striped cotton top, and her hair cascaded in waves over to the side, revealing beaded lime green and black earrings in the shape of lizards. Sanders’ short-sleeve plaid shirt looked clean and fresh. The sun set over Utopia’s low, red-roofed buildings, and the shrill blur of insects tussled with the frogs’ boggy croaks. The air was thick and warm. Fireflies flashed languidly, slow pulses of glowing and dimming light.

    “It was a good surprise to see the experiments up and running in the field now,” says Rodriguez, relaxing into the chair. “It’s been a process to get things going here. Finally to see it happening—it’s difficult, but it’s achievable. A good feeling.”

    Early on, the team had learned that Mycovitro’s own variety of mycorrhizal fungi increased cassava yields by as much as 20%. Now their own custom, lab-grown microbes were being tested. They had two studies in the field: one in which the cassava were planted in black plastic bags, and a second later one in which the cassava were planted directly in the field, with uninnoculated cassava as a barrier. Each study would take 11 months—the full time for a cassava to reach maturity.

    The first plants in the plastic bags looked a bit sickly; they’d be harvested in October. The second experiment with the plants directly in the ground were flourishing. Those would be harvested the following spring.

    Rodriguez is generally the positive one of the pair, sure that they can find a way to work through all challenges. Sanders tends to be more cautious, more pessimistic. “In Switzerland,” he joked, “we think of every single problem that could happen, and people here in Colombia are extremely optimistic—‘No worry! It will work!’” Rodriguez laughed in response. But things were looking good. Both scientists were pleased—even excited—about what they’d seen. Rodriguez’s optimism appeared justified.

    Her sunny outlook was tested only a few weeks later. The skies of the llanos, often thick and lazy with morning drizzle, turned dark. The clouds unleashed a month’s worth of merciless rain in only 48 hours. Water swept down over the cassava. When the rains finally faded, plant matter was clogging most of the field drains. Liquid mirrors pooled across the research field. Some of the plants, their roots surrounded by water and gasping for oxygen, listed to the side.

    Ceballos, the PhD student in charge of the project, heard the news first. She panicked and ran to Rodriguez to tell her what had happened. Rodriguez panicked as well, thinking, “What are we going to do?” But she quickly regrouped. “We need data,” she told Ceballos, and then called Sanders.

    un
    Unearthing cassava roots

    After a few days, students from Utopia who were dispatched to check on the fields sent back photos. Variation 1, with the older plants trapped in plastic bags, was fine. In the second one with healthier plants, the team received an incredible turn of luck. True, many of the plants were destroyed. But almost none of them had been coated with the fungi. Instead, almost all the dead cassava were just border plants.

    Sanders was relieved. “It would have been a disaster for us,” he says, if the plants had died. It would have set the project back at least a year—and the team’s funding was due to end in the summer of 2014.

    Three months later, in October, it was time to harvest the plants in the plastic bags. Ceballos headed back to Utopia. Each day for a week, she and another graduate student worked with students, crouching down and cutting open the thick black plastic. They shoved aside the soil that clung, damp, to the roots. The cassava poked out, some thicker than others, all with pale, purplish skin, smooth and wet, peeking through the dirt. Their flesh was bright white and oozed milky droplets.

    we
    Utopia students weigh cassava roots in the field.

    The team uncovered more than a thousand roots. All were quickly weighed at Utopia. Then Ceballos hauled the best, least damaged representatives of each cassava plant back to Bogotá, nearly 800 pounds of food. She stored them in a cavernous new freezer the lab bought specifically for this purpose. Over the next few months, she tested each plant’s dry weight and evaluated its fibrousness, starch content, acid content, and other variables that attest to the overall quality.

    Sanders didn’t have high hopes for the first harvest. After all, the crops didn’t look nearly as healthy as the cassava planted straight in the field. But the results thus far have surprised—and delighted—him. The data hasn’t been published in a scientific journal yet, but, he says, “We have actually seen huge differences in the weight of the cassava roots—much larger differences than seen in the rice experiment. We thought it would work but not to such an extent.”

    Into the Mainstream

    Rusty Rodriguez’s approach is proving successful, too. In 2014, his company is releasing two products, one for rice and one for corn, and he plans to have additional products for a wider variety of crops available by 2015. Based on his company’s field research, test plants are able to tolerate more stress from swings in temperature or water availability, and they can defend themselves more effectively against pests. He says his team is now looking at helping farmers decrease the amount of fertilizer they use by employing the fungi. They’re also publishing scientific studies on their research.

    The major agricultural seed and chemical companies are taking notice. In the fall of 2013, Monsanto paid the Danish company Novozymes $300 million to form a partnership called the BioAg Alliance. Novozymes creates what they call “microbial yield and fertilizer enhancers,” among other products in a variety of sectors. The partnership strengthens Monsanto’s role in what they term “sustainable microbial technology.”

    The rest of the field seems to be following suit. The trade journal Agrow: World Crop Protection News, wrote that the biopesticide sector was finally no longer “fringe” in April of 2012, and by 2013 proclaimed that it is now an “intrinsic part of the crop protection industry.” In 2012, Bayer bought the small biopesticide company AgraQuest. Syngenta bought Pasteuria Bioscience, and also has an exclusive international deal to sell a Bacillus-based biofungicide. The FDA is testing the spraying of bacteria on tomatoes that can destroy the human-harming salmonella and prevent other forms of contamination.

    There are plenty of concerns in the field of applied microbes for agriculture. One is whether any product that is successful on one farm will be equally successful on another. Then there’s the concern about releasing microbes into new environments, which means that regulatory agencies are demanding extensive environmental tests before certifying new products.

    The Colombia team is sensitive to this, and they’re studying the existing microbial ecosystems in the presence of the new fungi. They’ve also sent a grad student into the Amazon to collect fungi from wild versions of cassava, fungi that have co-evolved with the cassava for thousands of years, in hopes that they can isolate, grow, and breed these cassava-loving fungi as well.

    film
    Thin filaments of mycorrhizal fungi form a dense network between roots.

    Sanders has an ambitious, seemingly quixotic goal that he figures could be completed in 15 years, maybe 20. He wants to breed enough genetically distinct lines of fungi and try them out with enough crops in enough different environments so that researchers can create what’s called an “association map.” He would start by characterizing the genetics of the fungus and then map them against the crops and the environment. By peering deeply enough into the genetic code, he hopes we can catch a glimpse of which genes make quinoa grow better in Peru, for example. That way scientists could breed a new species of fungus and know in advance which crop it would improve without having to undertake years of trials.

    It seems nearly impossible to do enough studies, with enough crops, in enough farmland around the world to generate such a map. Genetic solutions also frequently seem to dance out of reach. Sanders insists, though, that big, crazy scientific goals in agriculture are crucial. “As one of the senior people in the Food and Agriculture Organization of the United Nations said to me, ‘If scientists don’t do that, then we are in trouble in the future.’ I believe he is right.”

    Sanders and Rodriguez are now setting up studies in Africa, where farmers, like many in Colombia, can find it difficult to pay for fertilizers and suffer from low yields. Cassava is also one of the top crops there. The team has formed partnerships with local research centers to test varieties of fungi on cassava crops in African soil. They’re hoping the research will begin soon, but they’re still searching for funding.

    The scientists believe they’re on their way to achieving their goal of helping farmers grow more food, sustainably. Says Sanders, “We really have to be working extremely hard now to produce the technology that’s going to be used in 10, 15, 20 years’ time. Even if we have something that’s good now, we don’t stop. We have to go for something that’s much better.”

    See the full article here.

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  • richardmitnick 1:37 pm on October 31, 2014 Permalink | Reply
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    From NOVA: “Bioinspired Underwater Glue Could Soon Replace Stitches” 

    PBS NOVA

    NOVA

    Fri, 31 Oct 2014
    Sarah Schwartz

    It’s a sticky situation—in the best possible way. By combining proteins that mussels and bacteria use to stick to surfaces, scientists at the Massachusetts Institute of Technology have created a strong new underwater glue. This adhesive could tackle an important challenge in various fields, including surgery, where repairing wet surfaces is essential.

    For years, scientists have used marine organisms for insight in producing underwater glues. Water forms a “weak boundary” on surfaces it contacts, which prevents adhesives from attaching, says Dr. Herbert Waite, Professor of Molecular, Cellular, and Developmental Biology at the University of California, Santa Barbara. This becomes a challenge in fields where wet surfaces need to be repaired—marine salvage, dentistry, surgery, and more. But organisms like mussels and barnacles regularly overcome this obstacle, binding easily to wet rocks.

    The MIT team turned to these organisms for inspiration—and ingredients. “One of the promises in synthetic biology is to be able to mix and match and optimize biologically based materials,” says Dr. Timothy Lu, an associate professor in MIT’s Synthetic Biology group and an author of the study. Lu and his colleagues combined proteins from two different sources—the feet of mussels, and E. coli bacteria.

    mus
    By combining proteins that mussels and bacteria use to stick to surfaces, scientists at MIT have created a strong new underwater glue.

    A good adhesive has two properties, Waite says: It has to be able to stick to other surfaces, and it also has to bind to itself. DOPA, the protein mussels use to adhere to surfaces, can do both, but its behavior depends upon the conditions of its environment. Mussels use various “tricks” to control their DOPA that aren’t fully understood, Waite says. If you’re not a mussel, it can be hard to manage DOPA’s behavior.

    That’s where the second protein helps. Amyloids are also adhesive, water-resistant, and link strongly to one another. Barnacles, algae, and bacteria use them to stick to surfaces. Lu and his team saw an opportunity: “[W]e thought by combining the bacteria with the mussels, we might be able to get some synergistic behavior,” says Lu.

    The result was a glue stronger than any other bio-derived or bio-inspired adhesive made to date. Waite, who was not involved with the study, says the results “really impressed” him. The researchers only asked DOPA to work in the form where it adheres to surfaces, he explains, while the amyloid proteins held the glue together. This joint behavior gives the glue its strength.

    Lu believes that this is only the beginning. “We only looked at two of the proteins that are involved in mussel adhesion…If we could combine multiple proteins on top of that, maybe we can even get stronger performance,” he says. While the group has been focused on adhesion alone, in the future, the group plans to explore potential underwater and biomedical uses, says Lu.

    These biomedical applications could be profound, especially in surgery. Waterproof glues could help seal internal wounds, even when drenched in blood and other fluids. Sutures or staples are currently used to close such holes, but these are hard to affix and can damage tissues, says Dr. Jeffrey Karp, an associate professor at Brigham and Women’s Hospital and Harvard Medical School. Karp, who was not involved in the MIT study.

    “There’s a huge unmet need for better adhesives,” says Karp, who is also a co-founder of Gecko Biomedical, which is developing medical adhesives. “There’s really nothing available in the clinic that works well and doesn’t have its drawbacks,” he adds, calling Lu’s team’s work “excellent and very promising.” The next step, Karp says, is to test the glue at larger scales.

    To work inside the human body, an adhesive must be biocompatible, or “cell-friendly.” But strong glues are often toxic. “We really don’t have anything that is strong and biocompatible,” says Dr. Pedro del Nido, a specialist in cardiac surgery at Boston’s Children’s Hospital who was not involved with the MIT study.

    Lu says his group is interested in testing for biocompatibility and believes that natural sources will yield better biocompatible materials. Looking to nature for advice has served him well so far. “[N]ature has solved a lot of the same problems that we deal with in pretty creative ways…Often times, borrowing upon nature and then applying the tools that we have in our arsenal to improve those properties, I think, is a really powerful way to go.”

    See the full article here.

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  • richardmitnick 2:46 pm on October 17, 2014 Permalink | Reply
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    From NOVA: “Insulin-Producing Stem Cells Could Provide Lasting Diabetes Treatments” 

    PBS NOVA

    NOVA

    Fri, 17 Oct 2014
    Sarah Schwartz

    Researchers have crafted what may be a powerful weapon in the fight against diabetes: A new line of insulin-producing cells that has been shown to reverse diabetes in mice within forty days. Scientists hope that these cells may someday do the same in humans.

    The new cells, called “Stage 7” or “S7” for their seven-step production process, are the product of a study by researchers at the University of British Columbia and the pharmaceutical company Janssen. S7 cells are made to mimic human beta cells, which are damaged or destroyed in patients with diabetes. Healthy beta cells produce insulin and help regulate blood sugar; S7 cells are grown from human embryonic stem cells and are programmed to do the same.

    cells
    A microscopic view of beta cells derived from stem cells

    “The advance that they have made is that they’ve got better cells in the test tube, cells that have more insulin and can secrete insulin in response to glucose,” said Dr. Gordon Weir, a physician and researcher at Joslin Diabetes Center and Harvard Medical School. “People haven’t been able to do that before.”

    Human embryonic stem cells, like those used to produce the S7 line, show great promise for producing beta cell replacements. Just last week, another team of researchers led by Dr. Douglas Melton at Harvard University announced their own line of insulin-producing cells, also produced from human embryonic stem cells. Like S7 cells, the Harvard team’s cells produce insulin in response to high blood sugar and can reverse diabetes symptoms in mice.

    The hope is that cells like these could be injected into diabetic patients, restoring normal beta cell function. Timothy Kieffer, head of the diabetes research group at University of British Columbia and a co-author of the S7 cell study, said that treatment with these cells could be curative, though other researchers caution that additional work has to be done before that’s the case.

    Cellular transplantation has already been shown to effectively combat diabetes. Since the late 1980s, beta cells extracted from cadaver pancreases have been used to normalize blood sugar in diabetics. But these treatments are not an option for many patients. In addition to the challenges of establishing a treatment program, Weir said, “there aren’t enough pancreatic donors to even scratch the surface.” These transplanted cells also tend to stop working over time, said Dr. David Nathan, the director of the Diabetes Center and Clinical Research Center at Massachusetts General Hospital. Whole organ pancreatic transplants usually last longer and have been increasingly successful in recent years, Nathan says. But both organ and cell transplants from cadavers require immunosuppressive treatments, which can cause tumors, skin cancers, and weakened immune systems.

    Beta cells grown from stem cells could solve some of these problems. It is possible that stem cells could be developed to reduce or eliminate the need for immunosuppression, Nathan said. Plus, their supply is theoretically unlimited. “If you can make them in a test tube, in a dish, whatever—well, that gets rid of the problem of donor pancreases,” Nathan said. While S7 cells are most efficient when made from human embryonic stem cells, they can also be made using induced pluripotent stem cells, which are reprogrammed adult cells. This, Weir noted, could eliminate “ethical issues” involved with embryonic stem cell use.

    Kieffer believes that a stem cell-based treatment would also be superior to insulin supplementation, the current standard of treatment for type 1 diabetes. In type 1 diabetes, which Kieffer’s research targets, beta cells are destroyed by an autoimmune attack, and patients require external insulin to survive. Even with advanced treatment options like insulin pumps, Weir said, it is challenging to keep blood sugar in a normal range. “And if you push hard enough to drive the blood sugar down, you end up getting into trouble with insulin reactions,” Weir said. “The blood sugar goes too low and that’s dangerous.”

    But S7 cells have some challenges to overcome before they can replace current treatments. For one, it can be difficult to control the development of stem cells, Nathan pointed out. Kieffer agreed that more research is needed to mature the cells, which are still not identical to human beta cells because they react more slowly to sugar and don’t release as much insulin. Kieffer’s collaborators are also working to scale up production of the S7 line. Meanwhile, the Harvard study uses a protocol that already seems to allow relatively large-scale development of insulin-producing cells.

    There are also other challenges to treating type 1 diabetes with cells like S7 because of the autoimmune nature of the disease. If beta cell transplants are injected into type 1 diabetics, Weir said, “those cells are still going to be subject to the immune problem that killed the cells in the first place.” Kieffer said that the “next hurdle” for his team is to see if S7 cells will work inside devices that prevent immune attack.

    These “immunobarrier” devices are essentially capsules that contain implanted stem cells, allowing the exchange of nutrients and insulin while blocking attacking immune cells. Nathan and Weir expressed reservations about these devices. Nathan wondered if they can be designed to allow sufficient blood flow and nutrients to all the cells inside, while Weir questioned whether there could be a device large enough to hold the number of cells needed to control the disease. Still, in August, the company Viacyte started clinical trials with such a device, using a line of cells less developed than S7. “We’ll have to wait and see,” Weir said.

    Because of the autoimmunity problem inherent in type 1 diabetes, Weir says that it may be easier to use beta cell transplantations to treat type 2 diabetes instead. Up to 95% of diabetic patients have this form of the disease, which involves no autoimmunity. Instead, in type 2, beta cells “wear out” such that the body stops responding to insulin.

    “You can take a type 2 diabetic and give them insulin injections and normalize the sugar if you do it carefully,” Weir said. “So, a beta cell transplant is just the same thing as giving an insulin injection.” He feels the effects of such treatment could be profound. “You can put cells in and normalize the blood sugar for years,” he said. “So if you want to call that a cure, I’d go along with that.” Nathan disagrees: because type 2 diabetics have some pancreatic function, it can be simpler and easier to treat their symptoms. Because of this, he believes that cellular transplantations will mostly be useful to combat type 1 diabetes.

    Nathan doesn’t think that beta cell transplantations are an “appropriate clinical option”—yet. “The balance between risk and benefit isn’t quite right,” he says. Still, he hopes that someday, a cellular treatment will be advanced enough to safely and effectively treat this disease. “To cure type 1 diabetes would be a godsend,” he says. “To actually do a single procedure that essentially takes away the disease at low risk would be great.”

    Though several questions must be answered before they start curing patients, S7 cells are a promising step in the fight against a disease that affects 347 million people worldwide. The field is moving quickly towards its goal; as Kieffer writes, “I am very optimistic that we are narrowing down on a cure for diabetes.”

    See the full article here.

    NOVA is the highest rated science series on television and the most watched documentary series on public television. It is also one of television’s most acclaimed series, having won every major television award, most of them many times over.

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  • richardmitnick 11:15 am on October 15, 2014 Permalink | Reply
    Tags: , , Loop Quantum Gravity, NOVA, Quantum Gravity, , , White Holes   

    From NOVA: “Are White Holes Real?” 

    PBS NOVA

    NOVA

    Tue, 19 Aug 2014
    Maggie McKee

    Sailors have their krakens and their sea serpents. Physicists have white holes: cosmic creatures that straddle the line between tall tale and reality. Yet to be seen in the wild, white holes may be only mathematical monsters. But new research suggests that, if a speculative theory called loop quantum gravity is right, white holes could be real—and we might have already observed them.

    wh

    A white whole is, roughly speaking, the opposite of a black hole. “A black hole is a place where you can go in but you can never escape; a white hole is a place where you can leave but you can never go back,” says Caltech physicist Sean Carroll. “Otherwise, [both share] exactly the same mathematics, exactly the same geometry.” That boils down to a few essential features: a singularity, where mass is squeezed into a point of infinite density, and an event horizon, the invisible “point of no return” first described mathematically by the German physicist Karl Schwarzschild in 1916. For a black hole, the event horizon represents a one-way entrance; for a white hole, it’s exit-only.

    There is excellent evidence that black holes really exist, and astrophysicists have a robust understanding of what it takes to make one. To imagine how a white hole might form, though, we have to go out on a bit of an astronomical limb. One possibility involves a spinning black hole. According to [Albert] Einstein’s general theory of relativity, the rotation smears the singularity into a ring, making it possible in theory to travel through the swirling black hole without being crushed. General relativity’s equations suggest that someone falling into such a black hole could fall through a tunnel in space-time called a wormhole and emerge from a white hole that spits its contents into a different region of space or period of time.

    Though mathematical solutions to those equations exist for white holes, “they’re not realistic,” says Andrew Hamilton, an astrophysicist at the University of Colorado at Boulder. That is because they describe universes that contain only black holes, white holes and wormholes—no matter, radiation or energy. Indeed, previous research, including Hamilton’s, suggests that anything that falls into a spinning black hole will essentially plug up the wormhole, preventing the formation of a passage to a white hole.

    But there’s a light at the end of the wormhole, so to speak. General relativity, from which Hamilton draws his predictions, breaks down at a black hole’s singularity. “The energy density and the curvature become so large that classical gravity is not a good description of what’s happening there,” says Stephen Hsu, a physicist at Michigan State University in East Lansing. Perhaps a more complete model of gravity—one that works as well on the quantum scale as it does on large ones—would negate the instability and allow for white holes, he says.

    Indeed, a unified theory that merges gravity and quantum mechanics is one of the holy grails of contemporary physics. Applying one such theory, loop quantum gravity, to black holes, theorists Hal Haggard and Carlo Rovelli of Aix-Marseille University in France have shown that black holes could metamorphose into white holes via a quantum process. In July, they published their work online.

    Loop quantum gravity proposes that space-time is made up of fundamental building blocks shaped like loops. According to Haggard and Rovelli, the loops’ finite size prevents a dying star from collapsing all the way down into a point of infinite density, and the shrinking object rebounds into a white hole instead. This process may take just a few thousandths of a second, but thanks to the intense gravity involved, the effects of relativity make the transformation appear to take much, much longer to anyone watching from afar. That means that minuscule black holes born in the infant universe could “now be ready to pop off like firecrackers,” forming white holes, according to a report in Nature. Some of the explosions astronomers thought were supernovae may actually be the wails of newborn white holes.

    The black-to-white conversion could resolve a nettlesome conundrum known as the black hole information paradox. The notion that information can be destroyed is anathema in physics, and general relativity says that anything, including information, that falls into a black hole can never escape. These two statements are not at odds if black holes simply act as locked safes for any information they slurp up, but Stephen Hawking showed 40 years ago that black holes actually evaporate over time. That led to the disturbing possibility that the information contained within them could be lost too, triggering a debate that rages to this day.

    But if a black hole instead turns into a white hole, then “all the information is recovered,” says Haggard. “We are quite excited about this mechanism because it avoids so many of the thorny issues that surround this discussion.”

    The new work is preliminary, however, and it is far from clear whether loop quantum gravity is an accurate description of reality. The only glimpse we get of white holes might turn out to be those we model in labs and kitchen sinks. But Carroll says that’s okay. Just thinking about these possibly mythical cosmic creatures can improve physicists’ intuition, “even if the real world is messy and not like those exact situations,” he says. “That’s the way in which white holes are very useful.”

    See the full article here.

    NOVA is the highest rated science series on television and the most watched documentary series on public television. It is also one of television’s most acclaimed series, having won every major television award, most of them many times over.

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  • richardmitnick 2:55 pm on October 3, 2014 Permalink | Reply
    Tags: , , , , , NOVA   

    From NOVA: “4 Multiverses You Might Be Living In” 

    PBS NOVA

    NOVA

    Published on Oct 3, 2014

    Could parallel universes exist? If so, what would they look like and how would they form?

    Watch, enjoy, learn.

    NOVA is the highest rated science series on television and the most watched documentary series on public television. It is also one of television’s most acclaimed series, having won every major television award, most of them many times over.

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  • richardmitnick 3:12 pm on September 27, 2014 Permalink | Reply
    Tags: , , , , NOVA   

    From NOVA: “It May Have Icy Clouds, But It’s Not a Planet, Not a Star, and Not in Our Solar System” 

    PBS NOVA

    NOVA

    Fri, 26 Sep 2014
    Joshua Sokol

    Brown dwarf W0855 was already special. A few times the size of Jupiter and super-cold, it’s halfway between a star and free-floating planet. Now ice clouds have been tentatively found in its atmosphere—which would mark the first time they’ve ever been seen on an extrasolar world.

    The solar system’s fourth-nearest companion doesn’t make it easy. It’s so faint that “I wanted to put on Rocky, do a Braveheart speech to the telescope operators,” said study author Jacqueline Faherty, who used the Las Campanas Observatory. in Chile [no hint of what telescope was used here]. She is the first astronomer to observe W0855 from the ground since it was found in data from NASA’s space-going Wide-Field Infrared Explorer (WISE) in April.

    Carnegie Las Campanas Observatory
    Las Campanas Observatory

    NASA Wise Telescope
    NASA/Wise

    w
    W0855, seen here in an artist’s conception, is a cold brown dwarf thought to have icy clouds in its soup of gases.

    Faherty’s work, which will be published in the Astrophysical Journal Letters, measured W0855’s brightness in different color bands. When compared with simulations of likely brown dwarf atmospheres, these data suggest W0855 boasts clouds of water ice and sulfide.

    On Earth, high-altitude cirrus clouds offer a point of comparison. Unlike cumulus clouds, which can contain both water vapor droplets and ice, cirrus clouds are composed of just ice crystals. Brown dwarf atmospheres are so cold and low-pressure that clouds there would form in much the same way, said astronomer Caroline Morley, whose published models were used by Faherty.

    Yet Morley and other astronomers unaffiliated with the study warn that this discovery is preliminary. “This tentative detection is made just with a few [brightness] points,” Morley wrote in an email. And Edward Wright, who studied W0855 with WISE, is skeptical that drawing conclusions from Morley’s models is the right idea. “The clouds depend on interpreting models which aren’t necessarily very good,” he said.

    It’s not that the presence of ice clouds would be shocking—just that they might not have been found yet. Kevin Luhman, who first discovered W0855, is also unconvinced. He wrote via email that, “there’s another set of cloudless models that she did not consider, and they actually agree well with her data.”

    According to these objectors, Faherty’s assumptions aren’t unreasonable. But her results depend on the brown dwarf having the same chemical blend as the Sun and on it being in chemical equilibrium—dependencies her paper also acknowledges.

    Regarding the cloud-free alternatives Luhman mentions, said Faherty, no “valid” models currently exist for comparison. Not only is the physics behind those other models unpublished, but the modelers themselves have lost confidence in their work, she said.

    All agree that NASA’s forthcoming James Webb Space Telescope will settle the question. The Webb’s coveted infrared sensitivity will let astronomers measure W0855’s whole spectrum, not just a few colors.

    For now, at least, Faherty is grateful even to find W0855 at new wavelengths and push the discussion forward. “It’s so faint that it’s at the limits, at the very hairy edge of what you can do from the ground,” she said. Her struggles with half-star, half-planet W0855 tease an even harder next step: understanding the atmospheres of planets orbiting faraway stars.

    See the full article here.

    NOVA is the highest rated science series on television and the most watched documentary series on public television. It is also one of television’s most acclaimed series, having won every major television award, most of them many times over.

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