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Wednesday, December 3rd, 2014
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| 12:00a |
Small volcanoes make a dent in global warming New research shows that relatively small volcanic eruptions can increase aerosol particles in the atmosphere, temporarily mitigating the global warming caused by greenhouse gases. The impact of such smaller eruptions has been underestimated in climate models, the researchers say, and helps to account for a discrepancy between those models and the actual temperatures observed over the last 15 years.
The findings are reported in a paper in the journal Geophysical Review Letters, co-authored by MIT Professor Susan Solomon, postdoc David Ridley, and 15 others. They help to explain the apparent slowdown in the pace of global warming recorded over the last 10 to 15 years — possibly explaining as much as half of that slowdown, the researchers say.
“We’ve learned a lot of new things about how the Earth’s climate changes, not just from year to year but from decade to decade, as a result of recent research,” says Solomon, the Ellen Swallow Richards Professor of Atmospheric Chemistry and Climate Science at MIT. “Several independent sets of observations show that relatively modest volcanic eruptions are important.”
For the last several years, “It’s been quite clear that the observed trends are not following what the models say,” Ridley adds: While the overall warming trend continues, its rate is slower than projected. Previous research has suggested that some of that discrepancy can be accounted for by an increase in the amount of warm water being carried down to the deep ocean, but other processes can also contribute.
The cooling effect of large volcanic eruptions, such as that of Mount Pinatubo in the Philippines in 1991, was already widely recognized; the new work shows that smaller eruptions can have a significant cooling effect as well, and provides a better estimate of how much of the recent reduction in warming could be explained by such eruptions: about 30 to 50 percent of the discrepancy, the team found.
The team found that small eruptions produce a significant amount of aerosol particles, which reflect sunlight, in a region of the upper atmosphere that is relatively poorly monitored: Satellites can provide good data about the atmosphere down to around 15 kilometers above ground level, below which clouds interfere. The team filled in the missing region using multiple balloon, laser radar (lidar), and ground-based measurements.
Aerosols in that intermediate zone, from about a dozen modest eruptions around the world during the last 15 years, may double previous estimates of the cooling effect of eruptions, Ridley says.
“It’s always exciting in science when you can find multiple measurements that lead to a common conclusion,” Solomon adds. “Several independent sets of observations now show that relatively modest volcanic eruptions are more important for global climate than previously thought.”
Overall, these smaller eruptions have lowered the increase of global temperature since 2000 by 0.05 to 0.12 degrees Celsius, counteracting some of the warming that would otherwise have occurred. Now, using this new information, groups that carry out climate modeling can update their models to more accurately project global climate change over the coming decades, Ridley says.
Alan Robock, a professor of environmental sciences at Rutgers University, says, “This work helps to better quantify the impacts of the most important natural cause of climate change, volcanic eruptions. We have an imperfect observational system for volcanic aerosols, and this work exploits some previously unused sources of information to better quantify the effects of small eruptions for the past decade.”
Robock, who was not involved in this research, adds that in light of these findings, “We need a more robust observing system for volcanic aerosols, to do a better job of measuring future small eruptions.”
Ridley and Solomon were the lead authors of this paper, joining authors from Wyoming, Russia, Germany, Japan, California, New York, Virginia, Colorado, and the U.K. The work was supported by the National Science Foundation, the Ministry of Science and Education of the Russian Federation, and the Russian Science Foundation. | | 5:00a |
Computer model enables design of complex DNA shapes MIT biological engineers have created a new computer model that allows them to design the most complex three-dimensional DNA shapes ever produced, including rings, bowls, and geometric structures such as icosahedrons that resemble viral particles.
This design program could allow researchers to build DNA scaffolds to anchor arrays of proteins and light-sensitive molecules called chromophores that mimic the photosynthetic proteins found in plant cells, or to create new delivery vehicles for drugs or RNA therapies, says Mark Bathe, an associate professor of biological engineering.
“The general idea is to spatially organize proteins, chromophores, RNAs, and nanoparticles with nanometer-scale precision using DNA. The precise nanometer-scale control that we have over 3-D architecture is what is centrally unique in this approach,” says Bathe, the senior author of a paper describing the new design approach in the Dec. 3 issue of Nature Communications.
The paper’s lead authors are postdoc Keyao Pan and former MIT postdoc Do-Nyun Kim, who is now on the faculty at Seoul National University. Other authors of the paper are MIT graduate student Matthew Adendorff and Professor Hao Yan and graduate student Fei Zhang, both of Arizona State University.
DNA by design
Because DNA is so stable and can easily be programmed by changing its sequence, many scientists see it as a desirable building material for nanoscale structures. Around 2005, scientists began creating tiny two-dimensional structures from DNA using a strategy called DNA origami — the construction of shapes from a DNA “scaffold” strand and smaller “staple” strands that bind to the scaffold. This approach was later translated to three dimensions.
Designing these shapes is tedious and time-consuming, and synthesizing and validating them experimentally is expensive and slow, so researchers including Bathe have developed computer models to aid in the design process. In 2011, Bathe and colleagues came up with a program called CanDo that could generate 3-D DNA structures, but it was restricted to a limited class of shapes that had to be built on a rectangular or hexagonal close-packed lattice of DNA bundles.
In the new paper, Bathe and colleagues report a computer algorithm that can take sequences of DNA scaffold and staple strands and predict the 3-D structure of arbitrary programmed DNA assemblies. With this model, they can create much more complex structures than were previously possible.
The new approach relies on virtually cutting apart sequences of DNA into subcomponents called multi-way junctions, which are the fundamental building blocks of programmed DNA nanostructures. These junctions, which are similar to those that form naturally during DNA replication, consist of two parallel DNA helices in which the strands unwind and “cross over,” binding to a strand of the adjacent DNA helix.
After virtually cutting DNA into these smaller sections, Bathe’s program then reassembles them computationally into larger programmed assemblies, such as rings, discs, and spherical containers, all with nanometer-scale dimensions. By programming the sequences of these DNA components, designers can also easily create arbitrarily complex architectures, including symmetric cages such as tetrahedrons, octahedrons, and dodecahedrons.
“The principal innovation was in recognizing that we can virtually cut these junctions apart only to reassemble them in silico to predict their 3-D structure,” Bathe says. “Predicting their 3-D structure in silico is central to diverse functional applications we’re pursuing, since ultimately it is 3-D structure that gives rise to function, not DNA sequence alone.”
The new program should enable researchers to design many more structures than those allowed by the CanDo program, says Paul Rothemund, a senior research associate at Caltech who was not part of the research team.
“Since a large fraction of the DNA nanotech community is currently using molecules whose structures could not be treated by the original CanDo, the current work is a highly welcome advance,” Rothemund says.
The researchers plan to make their algorithm publicly available within the next few months so that other DNA designers can also benefit from it. In the current version of the model, the designer has to come up with the DNA sequence, but Bathe hopes to soon create a version in which the designer can simply give the computer model a specific shape and obtain the sequence that will produce that shape. This would enable true nanometer-scale 3-D printing, where the “ink” is synthetic DNA.
Scaffolds and molds
Once researchers have access to printing 3-D nanoscale DNA objects of arbitrary geometries, they can use them for many different applications by combining them with other kinds of molecules. “These DNA objects are passive structural scaffolds,” Bathe says. “Their function comes from other molecules attached to them.”
One type of molecule that Bathe has begun working with is light-harvesting molecules called chromophores, which are a key component of photosynthesis. In living cells, these molecules are arranged on a protein scaffold, but proteins are more difficult to engineer into nanoscale assemblies, so Bathe’s team is trying to mimic the protein scaffold structure with DNA.
Another possible application is designing scaffolds that would allow researchers to mimic bacterial toxin assemblies made from multiple protein subunits. For example, the Shiga toxin consists of five protein subunits arranged in a specific pentameric structure that enables stealthy entry into cells. If researchers could reproduce this structure, they could create a version whose toxic parts are disabled, so that the remainder can be used for delivering drugs and micro- or messenger RNAs.
“This targeting subunit is very effective at getting into cells, and in a way that does not set off a lot of alarms, or result in its degradation by cellular machinery,” Bathe says. “With DNA we can build a scaffold for that entry vehicle part and then attach it to other things — cargo like microRNAs, mRNAs, cancer drugs, and other therapeutics.”
The researchers have also used DNA nanostructures as molds to form tiny particles of gold or other metals. In a recent Science paper, Bathe and colleagues at Harvard University’s Wyss Institute for Biologically Inspired Engineering demonstrated that DNA molds can shape gold and silver into cubes, spheres, and more complex structures, such as Y-shaped particles, with programmed optical properties that can be predicted by computer model. This approach offers a “made-to-order” nanoparticle design and synthesis procedure with diverse applications in nanoscale science and technology.
The current research was funded by the Office of Naval Research and the National Science Foundation. | | 2:05p |
Report details steps needed to accelerate innovation at MIT Innovation in the service of society has been at the core of MIT’s mission since the Institute’s founding more than 150 years ago.
Now a preliminary report, leading up to the launch of an MIT Innovation Initiative, is proposing a series of steps aimed at fortifying MIT’s culture of innovation — suggesting a suite of resources, programs, and facilities to aid in bringing significant innovations out of the labs and into the daily lives of people around the world, and to do so faster and more effectively.
Compilation of the report was led by the co-directors of the Innovation Initiative: Vladimir Bulovic, the Fariborz Maseeh Professor of Emerging Technology, and Fiona Murray, the William Porter Professor of Entrepreneurship. The two professors are associate deans for innovation in the School of Engineering and the MIT Sloan School of Management, respectively.
The effort was initiated in October 2013 by MIT President L. Rafael Reif. In his charge to the advisory committee, established to define the scope and goals of the new Innovation Initiative, Reif wrote, “With an interdisciplinary attitude and an appetite for hands-on problem solving, we define compelling new questions, attack them in novel ways — and bring our students with us every step.”
The report reflects contributions from a 19-member faculty advisory committee, led by Bulovic and Murray, and including representatives from all five of MIT’s schools. The report, based on substantive research and input from stakeholders both inside and outside MIT, outlines a set of priorities to help the Institute in supporting innovation, and a set of proposals to be prioritized and implemented over time.
“At MIT, our mission directs us to advance knowledge and educate students in service to the nation and the world; this profound work will always be our central focus and inspiration,” Reif wrote in a letter to the MIT community introducing the preliminary report, and welcoming feedback. “But our mission also compels us to bring knowledge to bear on the world’s great challenges — a good working definition of innovation as we practice it at MIT. With this new initiative, we have an opportunity to deliver better solutions to the world — and in the process, to deliver to the world a better MIT.”
A legacy of innovation
The preliminary report, titled “The MIT Innovation Initiative: Sustaining and Extending a Legacy of Innovation,” observes: “MIT will always be defined by its central focus on education and research. Yet more and more, innovation belongs to our mission as well.”
MIT’s forthcoming Innovation Initiative, the report adds, is focused on “providing a forum and a framework for enhancing the Institute’s innovation engine in ways that accelerate our community’s ability to transform brilliant ideas and fundamental research into positive and substantive social and economic impact.”
The report outlines a series of steps to foster these goals; some could be implemented immediately, while others will require further study and discussion to refine their details. The recommendations encompass four broad priorities:
- strengthening and expanding MIT’s innovation capabilities;
- cultivating communities that connect across campus and engage MIT with broader worldwide innovation needs;
- developing additional, transformative hands-on infrastructure; and
- formalizing, studying, and promoting the science of innovation through a new Laboratory for Innovation Science and Policy.
The report emphasizes that these steps represent a continuation of MIT’s longtime approach to education and research: Already, the study says, the Institute offers more than 50 courses specifically related to innovation and entrepreneurship, across all five of its schools, enrolling more than 3,000 students. Other programs and competitions, including undergraduate research opportunities and MIT’s annual $100K Entrepreneurship Competition, have involved thousands more students in activities related to innovation.
Growing demand
While such programs are an established part of MIT’s culture, the report notes that they are so popular that the Institute cannot meet current demand for them — either in terms of physical facilities, or in financing for such things as prototyping facilities and support for entrepreneurial projects. In addition, the report says, there is a clear desire for more ways to facilitate collaborations across schools and departments, and for more ways for MIT’s innovators to interact with communities around the world.
“We need to get better at recognizing and responding to the sorts of global challenges that exist,” Murray says. “We need to ensure that MIT’s solutions actually reach the people who need them by designing the right kinds of organizations and policies to ensure they reach impact.”
Specific proposals in the preliminary report include education with greater emphasis on learning that goes beyond traditional academic knowledge and research — specifically, encouraging solutions to real-world problems, scaling them up, and delivering them where they are needed. Toward that end, the report suggests creation of an undergraduate minor, a graduate certificate in innovation, and programming for postdocs.
“Our students are driven to make a positive difference in the world,” Bulovic says. “While at MIT, we need to enable them to hone their skills in translating ideas to innovations, so they can go on to provide solutions that scale rapidly and achieve broad positive impact.”
Opportunities on- and off-campus
The establishment of vibrant, small-scale global innovation communities to expand MIT’s innovation footprint is described in the report as another priority. These might bring together alumni, students, faculty, outside entrepreneurs, policymakers, and funding sources, all of whom could work together on problem-solving and implementation of solutions. The report states that by engaging with stakeholders around the world there is an opportunity to build on the long tradition of “science diplomacy” that forged mutually beneficial relationships among scientists around the world to inspire an era of “innovation diplomacy” On campus, specific suggestions include better coordination of MIT’s many hackathons, festivals, and competitions related to innovation, as well as a student leadership council to help coordinate the activities of the more than 40 existing student groups and clubs focused on innovation and entrepreneurship.
The report proposes a significant expansion of infrastructure, such as spaces for scaling up innovations, and the development of new sources of funding — such as new faculty innovations fellowships, visiting partnerships, and innovation advocates who could work with on-campus teams to help develop innovative ideas. Dedicated innovation spaces, situated in various locations around campus, could provide facilities and equipment specifically geared toward the development of both inventions and the teams to carry them forward. Expansion of the present research seed-grant programs, and establishment of new ones, would support dedicated research time for translating ideas into prototypes, accelerating their path to scale-up and impact.
Another key goal of the report: fostering and developing a “science of innovation.” The report notes, “We believe that the drivers and outcomes of innovation warrant rigorous, multidisciplinary analysis that increases our understanding of how to generate innovation more constructively, efficiently and effectively.” The report also proposes creation of a Laboratory for Innovation Science and Policy to “develop new knowledge of the innovation process; promote new data, methods and metrics related to innovation science; and translate evidence-based insights into practical recommendations for industrial and policy partners.”
Bulovic and Murray welcome thoughts from all members of the MIT community on the framework and scope of the activities outlined in the report. They will host several community briefings; the first of these will occur Monday, Dec. 8, from 3 to 4 p.m. in Room E14-633. Feedback may also be sent to innovation@mit.edu. |
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