#Cracked metal heal thyself It was a result so unexpected that MIT researchers initially thought it must be a mistake:
Under certain conditions, putting a cracked piece of metal under tension that is, exerting a force that would be expected to pull it apart has the reverse effect,
The results were published in the journal Physical Review Letters in a paper by graduate student Guoqiang Xu
and professor of materials science and engineering Michael Demkowicz. e had to go back and check, Demkowicz says, when nstead of extending,
The answer turned out to lie in how grain boundaries interact with cracks in the crystalline microstructure of a metal in this case nickel,
which is the basis for uperalloysused in extreme environments, such as in deep-sea oil wells. By creating a computer model of that microstructure and studying its response to various conditions,
e found that there is a mechanism that can, in principle, close cracks under any applied stress,
Demkowicz says. A computer simulation of the molecular stucture of a metal alloy, showing the boundaries between microcystalline grains (white lines forming hexagons),
shows a small crack (dark horizontal bar just right of bottom center) that mends itself as the metal is put under stress.
This simulation was one of several the MIT researchers used to uncover this new self-healing phenomenon.
Simulation courtesy of Guoqiang Xu and Michael Demkowicz Most metals are made of tiny crystalline grains
The very idea that crystal grain boundaries could migrate within a solid metal has been studied extensively within the last decade,
These defects have intense stress fields, which an be so strong, they actually reverse what an applied load would do,
it can heal. he stress from the disclinations is leading to this unexpected behavior, he says.
the researchers plan to study how to design metal alloys so cracks would close and heal under loads typical of particular applications.
Techniques for controlling the microstructure of alloys already exist, Demkowicz says, so it just a matter of figuring out how to achieve a desired result. hat a field wee just opening up,
The technique might also apply to other kinds of failure mechanisms that affect metals, such as plastic flow instability akin to stretching a piece of taffy until it breaks.
Metal fatigue, for example which can result from an accumulation of nanoscale cracks over time s probably the most common failure modefor structural metals in general
William Gerberich, a professor of chemical engineering and materials science at the University of Minnesota who was involved not in this research,
in conjunction with stress-driven grain boundary migration, could actually heal cracks. This is indeed provocative
The work was funded by the BP-MIT Materials and Corrosion Center l
#Better robot vision Object recognition is one of the most widely studied problems in computer vision.
But a robot that manipulates objects in the world needs to do more than just recognize them;
To improve robots ability to gauge object orientation Jared Glover a graduate student in MIT s Department of Electrical engineering
and Computer science is exploiting a statistical construct called the Bingham distribution. In a paper they re presenting in November at the International Conference on Intelligent Robots
and Systems Glover and MIT alumna Sanja Popovic 12 MENG 13 who is now at Google describes a new robot-vision algorithm based on the Bingham distribution that is 15 percent better than its best
That algorithm however is for analyzing high-quality visual data in familiar settings. Because the Bingham distribution is a tool for reasoning probabilistically it promises even greater advantages in contexts where information is patchy or unreliable.
In ongoing work Glover is using Bingham distributions to analyze the orientation of pingpong balls in flight as part of a broader project to teach robots to play pingpong.
In cases where visual information is particularly poor his algorithm offers an improvement of more than 50 percent over the best alternatives.
And ambiguity is really the central challenge to getting good alignments in highly cluttered scenes like inside a refrigerator or in a drawer.
because it allows the algorithm to get more information out of each ambiguous local feature.
Because Bingham distributions are so central to his work Glover has developed also a suite of software tools that greatly speed up calculations involving them.
The software is freely available online for other researchers to use. In the rotationone reason the Bingham distribution is so useful for robot vision is that it provides a way to combine information from different sources.
Generally determining an object s orientation entails trying to superimpose a geometric model of the object over visual data captured by a camera in the case of Glover s work a Microsoft Kinect camera
Imagine too that software has identified four locations in an image where color or depth values change abruptly likely to be the corners of an object.
Most algorithms Glover s included will take a first stab at aligning the points. In the case of the tetrahedron assume that after that provisional alignment every point in the model is near a point in the object but not perfectly coincident with it.
and Popovic s algorithm to explore possible rotations in a principled way quickly converging on the one that provides the best fit between points.
The current version of Glover and Popovic s algorithm integrates point-rotation probabilities with several other such probabilities.
In experiments involving visual data about particularly cluttered scenes depicting the kinds of environments in which a household robot would operate Glover s algorithm had about the same false positive-rate rate as the best existing algorithm:
Glover argues that that difference is because of his algorithm s better ability to determine object orientations.
He also believes that additional sources of information could improve the algorithm s performance even further.
Gary Bradski vice president of computer vision and machine learning at Magic Leap and president and CEO of Opencv the nonprofit that oversees the most widely used open-source computer-vision software library believes that the Bingham
when an MIT senior named John Romanishin proposed a new design for modular robots to his robotics professor, Daniela Rus,
Two years later, Rus showed her colleague Hod Lipson, a robotics researcher at Cornell University, a video of prototype robots, based on Romanishin design,
In November, Romanishin now a research scientist in MIT Computer science and Artificial intelligence Laboratory (CSAIL) Rus,
a professor of electrical engineering and computer science and director of CSAIL. e just needed a creative insight
The sliding-cube model simplifies the development of self-assembly algorithms, but the robots that implement them tend to be much more complex devices.
Armies of mobile cubes could temporarily repair bridges or buildings during emergencies, or raise and reconfigure scaffolding for building projects.
And they could swarm into environments hostile or inaccessible to humans diagnose problems, and reorganize themselves to provide solutions.
or battery packs, or other equipment, which the mobile cubes could transport. n the vast majority of other modular systems,
In ongoing work, the MIT researchers are building an army of 100 cubes, each of which can move in any direction,
and designing algorithms to guide them. e want hundreds of cubes, scattered randomly across the floor,
#Seeing through silicon Scientists at MIT and the University of Texas at Arlington (UTA) have developed a new type of microscopy that can image cells through a silicon wafer,
a former postdoc in MIT Laser Biomedical Research center (LBRC) and one of the lead authors of a paper describing the technology in the Oct 2 issue of the journal Scientific Reports.
Other lead authors of the paper are former MIT postdoc Narahara Chari Dingari and UTA graduate students Bipin Joshi and Nelson Cardenas.
The senior author is Samarendra Mohanty, an assistant professor of physics at UTA. Other authors are former MIT postdoc Jaqueline Soares, currently an assistant professor at Federal University of Ouro Preto, Brazil,
and Ramachandra Rao Dasari, associate director of the LBRC. Silicon is used commonly to build ab-on-a-chipmicrofluidic devices,
as well as microelectronics devices. Such devices have many potential applications in research and diagnostics but they could be even more useful
who is now an assistant professor of mechanical engineering at Johns hopkins university. To achieve that, Barman and colleagues took advantage of the fact that silicon is infrared transparent to and near-infrared wavelengths of light.
which works by sending a laser beam through a sample, then splitting the beam into two.
and its refractive index a measure of how much the material forces light to bend as it passes through.
For this study, the researchers found that light with a wavelength of 980 nanometers worked best.
Using this system, the researchers measured changes in the height of red blood cells, with nanoscale sensitivity,
through a silicon wafer similar to those used in most electronics labs. As red blood cells flow through the body,
When these cells are infected with malaria they lose this ability to deform, and form clogs in tiny vessels.
it could also be used to study the dynamics of the malformed blood cells that cause sickle cell anemia.
The researchers also used their new system to monitor human embryonic kidney cells as pure water was added to their environment a shock that forces the cells to absorb water
an associate professor of electrical engineering and computer science at the University of Illinois at Urbana-Champaign who was not part of the research team. he possibilities are endless:
similar to a CT SCAN. The research was funded by the National Institute of Biomedical Imaging and Bioengineering and Nanoscope Technologies, LLC n
#Connecting Morocco#s artisans with the world Although tourism accounts for the second-largest industry within Morocco economy,
many Moroccan craftsmen who depend on tourism to earn their living still face significant economic hardship,
Having witnessed this struggle firsthand on a trip through the Atlas Mountains, MIT Supply Chain Management graduate student Zyad El Jebbari,
a Morocco native, was motivated to find innovative new ways to help his country craftsmen leverage the opportunities provided by a globalized economy.
and serve as a bridge between my country and the demand coming from all around the world.
A lack of literacy provides a challenging barrier to access the modern distribution channels of today fast-growing market demand for handmade goods. Current models for exporting
These artisans often rely on microcredit loans with high interest rates to fund their initial production, and can expect to see an average return of only 5 to 20 percent of the retail price of their goods. he supply chain design behind Morocrafts is part of Zyad business strategy,
says Edgar E. Blanco, a research director at the MIT Center for Transportation and Logistics and a Morocrafts advisory board member. t provides not only more transparency but also a connection between consumers and artisans,
Morocrafts aims to increase artisan earnings by up to 70 percent of retail price through maintaining a"low-to-no"inventory model in
The platform will also provide interest-free credit loans to artisans in order to ease barrier of entry,
#New way to model sickle cell behavior Patients with sickle cell disease often suffer from painful attacks known as vaso-occlusive crises, during
Blood transfusions can sometimes prevent such attacks, but there are currently no good ways to predict when a vaso-occlusive crisis,
says Ming Dao, a principal research scientist in MIT Department of Materials science and engineering. Now Dao and colleagues, including Subra Suresh, president of Carnegie mellon University, former dean of MIT School of engineering,
and Vannevar bush Professor of Engineering Emeritus, have developed a tiny microfluidic device that can analyze the behavior of blood from sickle cell disease patients.
This device can measure how long it takes blood cells to become dangerously stiff, making them more likely to get trapped in blood vessels.
It could also help researchers test the efficacy of new drugs for sickle cell disease which occurs in about 300,000 newborns per year, more than 75 percent of them in Africa.
The best drug now available, hydroxyurea, works for only about two-thirds of patients. The research team also includes the paper lead author, E (Sarah) Du,
a former MIT postdoc who is now an assistant professor at Florida Atlantic University; Monica Diez-Silva, a former research scientist in MIT Department of Materials science and engineering;
and Gregory Kato of the Department of Medicine at the University of Pittsburgh. Squeezing by People with sickle cell disease,
an inherited genetic disorder, have a variant form of hemoglobin that causes their red blood cells to take on a characteristic sickle shape when in low-oxygen conditions.
Patients now have an average life expectancy of 45 to 50 years in the United states, up from only 14 years as recently as 1973.
Disease severity varies among patients depending on how much abnormal hemoglobin is present in their cells. Sickle cells can squeeze through most blood vessels
but they can encounter problems when they enter very small capillaries (less than 20 micrometers in diameter,
He and his colleagues designed their microfluidic device to mimic the conditions inside a blood vessel as oxygen leaves the Blood cells flow through a narrow channel that wraps around a compartment containing oxygen.
Analyzing risk Using this device to measure blood samples from 25 sickle cell disease patients, the researchers were able to determine how deoxygenation affects red blood cellssickling rates;
if the device can be used to reliably predict individual patientsrisk of a vaso-occlusive crisis. his technique represents a major advance to further our understanding and treatment of vaso-occlusion due to sickle cell disease.
and treating other diseases where the deformability of blood cells is affected, says Guruswami Ravichandran, a professor of aeronautics and mechanical engineering at Caltech who was involved not in this study.
The researchers have filed a patent on the device to further its development for diagnostic use, and they also plan to pursue it as a tool to test potential new drugs for sickle cell disease.
To demonstrate the device usefulness for evaluating new drugs, the researchers analyzed a drug called Aes-103, now in phase II clinical trials to treat sickle cell disease,
and found that it helped prevent patientscells from clogging in the microfluidic channel. They also studied cells treated with hydroxyurea
The research was funded by the National institutes of health and Carnegie mellon University e
#New fibers can deliver many simultaneous stimuli The human brain complexity makes it extremely challenging to study not only because of its sheer size,
but also because of the variety of signaling methods it uses simultaneously. Conventional neural probes are designed to record a single type of signaling,
By producing complex multimodal fibers that could be less than the width of a hair, they have created a system that could deliver optical signals and drugs directly into the brain,
The new technology is described in a paper appearing in the journal Nature Biotechnology, written by MIT Polina Anikeeva and 10 others.
In addition to transmitting different kinds of signals, the new fibers are made of polymers that closely resemble the characteristics of neural tissues,
says Anikeeva, an assistant professor of materials science and engineering. To do that, her team made use of novel fiber-fabrication technology pioneered by MIT professor of materials science
(and paper co-author) Yoel Fink and his team, for use in photonics and other applications.
Flexible fiber-based probes The result, Anikeeva explains, is the fabrication of polymer fibers hat are soft and flexible
and look more like natural nerves. Devices currently used for neural recording and stimulation, she says,
are made of metals, semiconductors, and glass, and can damage nearby tissues during ordinary movement. t a big problem in neural prosthetics,
called a preform, of the desired arrangement of channels within the fiber: optical waveguides to carry light, hollow tubes to carry drugs,
and conductive electrodes to carry electrical signals. These polymer templates, which can have dimensions on the scale of inches,
are heated then until they become soft, and drawn into a thin fiber, while retaining the exact arrangement of features within them.
A single draw of the fiber reduces the cross-section of the material 200-fold, and the process can be repeated,
making the fibers thinner each time and approaching nanometer scale. During this process, Anikeeva says, eatures that used to be inches across are now microns.
Combining the different channels in a single fiber she adds, could enable precision mapping of neural activity,
and ultimately treatment of neurological disorders, that would not be possible with single-function neural probes.
For example, light could be transmitted through the optical channels to enable optogenetic neural stimulation, the effects
of which could then be monitored with embedded electrodes. At the same time, one or more drugs could be injected into the brain through the hollow channels,
while electrical signals in the neurons are recorded to determine, in real time, exactly what effect the drugs are having.
or therapeutic application by creating the exact combination of channels needed for that task. ou can have a really broad palette of devices,
While a single preform a few inches long can produce hundreds of feet of fiber, the materials must be selected carefully so they all soften at the same temperature.
The fibers could ultimately be used for precision mapping of the responses of different regions of the brain or spinal cord,
and ultimately may also lead to long-lasting devices for treatment of conditions such as Parkinson disease.
John Rogers, a professor of materials science and engineering and of chemistry at the University of Illinois at Urbana-Champaign who was involved not in this research
diverse collection of multifunctional fibers, tailored for insertion into the brain where they can stimulate
In addition to Anikeeva and Fink, the work was carried out by Andres Canales, Xiaoting Jia, Ulrich Froriep, Ryan Koppes, Christina Tringides, Jennifer Selvidge, Chi Lu, Chong Hou,
The work was supported by the National Science Foundation the Center for Materials science and engineering, the Center for Sensorimotor Neural engineering, the Mcgovern Institute for Brain Research, the U s army Research Office through the Institute for Soldier Nanotechnologies,
and the Simons Foundation n
#Decoding sugar addiction Together, obesity and Type 2 diabetes rank among our nation greatest health problem,
and they largely result from what many call an ddictionto sugar. But solving this problem is complicated more than solving drug addiction,
a principle investigator at the Picower Institute for Learning and Memory who previously developed novel techniques for studying brain circuitry in addiction
and anxiety. e need to study this circuit in more depth, but our ultimate goal is to develop safe,
For the study, Tye and her graduate student Edward Nieh focused on the connections between the VTA and the lateral hypothalamus (LH),
Electrodes recorded the activity of these identified neurons during animal behaviors. Mice naturally love sucrose similar to humans loving sugar-rich sodas
Next, Nieh worked with an MD/Phd student in Tye's lab, Stephen Allsop, to modify mice
or silence neurons with pulses of light, a method called optogenetics. Activating the projections led to compulsive sucrose-eating
and increased overeating in mice that were full. Inactivating this pathway reduced the compulsive sucrose-seeking that resembles addiction
because we have the recording data to show how this compulsive sugar-seeking happens, Nieh says,
who is also the Whitehead Career development Assistant professor in MIT's Department of Brain and Cognitive sciences. ow we have evidence showing that this transition is represented in the LH-VTA circuit.
with the long-term goal of establishing a new paradigm for treating obesity that could be applied to other neuropsychiatric disorders.
Additional funding came from multiple public and private sources, including Nieh NSF Graduate Research Fellowship, the Integrative Neuronal Systems Fellowship,
and the Training program in the Neurobiology of Learning and Memory. Kara N. Presbrey, Christopher A. Leppla, Romy Wichmann, Rachael Neve,
and Craig P. Wildes, all members of the Picower Institute, also contributed to this work a
#New findings reveal genetic brain disorders converge at the synapse Picower Institute for Learning and Memory January 12,
2015 SHARE Several genetic disorders cause intellectual disability and autism. Historically, these genetic brain diseases were viewed as untreatable.
However, in recent years neuroscientists have shown in animal models that it is possible to reverse the debilitating effects of these gene mutations.
But the question remained whether different gene mutations disrupt common physiological processes. If this were the case,
a treatment developed for one genetic cause of autism and intellectual disability might be useful for many others.
In a paper published today in the online edition of Nature Neuroscience a research team led by Mark Bear,
the Picower Professor of Neuroscience in MIT Picower Institute for Learning and Memory, showed that two very different genetic causes of autism
and intellectual disability disrupt protein synthesis at synapses, and that a treatment developed for one disease produced a cognitive benefit in the other.
The research was performed by postdoc and lead author Di Tian, graduate student Laura Stoppel, and research scientist Arnold Heynen, in collaboration with scientists at Cold Spring Harbor Laboratory and Roche pharmaceuticals.
Researching the role of fragile X syndrome One heritable cause of intellectual disability and autism is fragile X syndrome,
which arises when a single gene on the X chromosome, called FMR1, is turned off during brain development.
Fragile X is rare, affecting one in about 4, 000 individuals. In previous studies using mouse models of fragile X,
Bear and others discovered that the loss of this gene results in exaggerated protein synthesis at synapses, the specialized sites of communication between neurons.
Of particular interest, they found that this protein synthesis was stimulated by the neurotransmitter glutamate, downstream of a glutamate receptor called mglur5.
This insight led to the idea, called the mglur theory, that too much protein synthesis downstream of mglur5 activation gives rise to many of the psychiatric and neurological symptoms of fragile X. Bear lab tested this idea in mice,
and found that inhibiting mglur5 restored balanced protein synthesis and reversed many defects in the animal models.
Different genes, same consequences Another cause of autism and intellectual disability is the loss of a series of genes on human chromosome 16,
called a 16p11.2 microdeletion. Some of the 27 affected genes play a role in protein synthesis regulation, leading Bear and colleagues to wonder if 16p11.2 microdeletion syndrome and fragile X syndrome affect synapses in the same way.
To address this question, the researchers used a mouse model of 16p11.2 microdeletion, created by Alea Mills at Cold Spring Harbor Laboratory.
Using electrophysiological biochemical, and behavioral analyses, the MIT team compared this 16p11.2 mouse with what they already had established in the fragile X mouse.
Synaptic protein synthesis was disrupted indeed in the hippocampus, a part of the brain important for memory formation.
Moreover, when they tested memory in these mice, they discovered a severe deficit, similar to fragile X. Restoring brain function after disease onset These findings encouraged the MIT researchers to attempt to improve memory function in the 16p11.2 mice with the same approach that has worked in fragile X mice.
Treatment with an mglur5 inhibitor provided by a team of scientists at Roche led by Lothar Lindemann, substantially improved cognition in these mice.
The implication, according to Bear, is that ome cognitive aspects of this disease, previously believed to be an intractable consequence of altered early brain development,
Current research indicates that well over 100 distinct gene mutations can manifest as intellectual disability and autism.
as they indicate not only that drug therapies might be effective to improve cognition and behavior in affected individuals,
This research was supported in part by the Howard hughes medical institute, the National institute of mental health, the Simons Foundation, the Simons Center for the Social Brain at MIT,
#Products of progress Back in 2009, alumna Jodie Wu 9 launched Global Cycle Solutions (GCS) in Tanzania to bring small-scale farmers an innovative product she designed in MIT D-Lab:
a bike-mounted maize sheller. Easily attached to a bike and powered by pedaling, the low-cost,
cast-iron sheller allowed farmers to process their corn 10 times faster in one day, as opposed to weeks when done by hand.
By 2011, GCS had sold shellers to more than 1, 000 farmers. But its products still weren moving fast enough to fund product development, marketing, and sales.
Knowing that about 82 percent of Tanzanians more than 35 million households live off-grid, GCS began going to the villages and selling solar-powered lamps, which also charge cellphones.
Suddenly, its product started moving and fast. hat when we realized wee not facing a technology problem in the field;
whose employees visit villages across three regions of Tanzania Arusha, Morogoro, and Mwanza to research the most-needed
The startup still sells maize shellers upon request, but doesn advertise them.)The solar lamps, Wu says,
such lanterns spew out black carbon that contributes to global warming and indoor air pollution. These solar lamps save customers who make about $2 per day, on average roughly $70 apiece annually.
GCS alone has provided more than $4 million in energy savings since it started selling solar lanterns three years ago.
As most are farmers, she adds, the $6 in margin they earn from selling a single lamp during non-harvest months is feed enough to their family for a few days. t really about creating a win-win-win situation,
Wu says. e win in terms of bringing in profits, consumers win because they have products that help them save costs,
and entrepreneurs are getting money to put food on the table. Wee doing good through business.
In 2008, Wu was taking course 2. 722j (D-Lab: Design), taught by senior lecturer Amy Smith,
when she learned about the plight of 500 million small-scale farmers around the world still using only their hands and hoes for farming.
To shell corn, these farmers traditionally fill bags with cobs and beat them to loosen the kernels,
or simply remove the kernels by hand both of which could take weeks. As part of the class, Wu traveled to Tanzania to introduce farmers to a pedal-powered sheller developed by a Guatemalan organization called Mayapedal.
This machine resembles a stationary bike, with a wooden seat and a hand-cranked sheller at its side.
Cobs are fed into the sheller opening as someone pedals, and the kernels are stripped quickly into a bucket,
But this machine cost about $200 and weighed over 100 pounds, meaning villagers couldn easily afford
which are valuable commodities for Tanzanians. That when Wu engineered a solution. e were building this pedal-powered machine,
and other devices such as the cellphone charger that GCS later developed. e called it our universal adapter,
and use the new maize sheller: Farmers need only change a sprocket on the wheel
and gears on the upper part of the bike to attach and detach devices. Now not only could farmers process all their maize in one day,
but they also retained their bikes for other uses. In 2009, Wu continued developing the device
Participating in the $100k with help from fellow students in engineering and in the MIT Sloan School of management
lawyers, and accountants also showed Wu some significant errors in her financial planning. y first executive plan said I needed $20,
Wu launched GCS in Tanzania with only a few local employees, and has grown the startup to more than 35 employees, most of them Tanzanian.
Still, GCS connections to MIT have endured and at times have helped, in fact the startup thrive in spite of difficulties.
because I couldn even pay for my work permit to stay in Tanzania, Wu says. And over the years, D-Lab students have traveled frequently to Tanzania to help with product development,
conduct field research, and sometimes design new product prototypes. Some projects didn quite pan out such as a rice-threshing machine that had mechanical issues,
But GCS is now furthering development on a motorized multicrop thresher eveloped by a team of students that the Bill
and Melinda Gates Foundation has backed since with $100, 000. The product design is led by currently alumnus Elliot Avila 4
The current iteration of the 6-horsepower thresher which has evolved extensively after years of field-testing is wheeled a cylinder thresher that can both be adjusted to handle a variety of crops.
With a majority of farmers still threshing by hand Wu says, his could potentially transform the industry.
In 2012, Avila and two MIT students also fixed issues with the threads on the sheller drive shaft:
Sometimes maize wasn ejecting properly, and the machine would jam, coming to a sudden halt and putting stress on the threads,
causing them to fail. The students discovered the issue and used longer bolts with springs to secure the sheller so when the maize jammed,
the sheller stopped at a more gradual pace, reducing thread stress. All shellers could then be modified,
instead of recalled. -Lab has really been a great place to get talent, Wu says. Today, Wu spends her days overseeing operations at GCS,
focusing on identifying products that will improve village life and generate sales. However, one day she hopes to return to her design roots:
where the sheer numbers of our sales and deep understanding of customer needs will incentivize manufacturers to collaborate with us to make truly transformative products for the people we work with,
Overtext Web Module V3.0 Alpha
Copyright Semantic-Knowledge, 1994-2011