Steam energy from the sun: New spongelike structure converts solar energy into steam

A new material structure developed at MIT generates steam by soaking up the sun. The structure — a layer of graphite flakes and an underlying carbon foam — is a porous, insulating material structure that floats on water. When sunlight hits the structure’s surface, it creates a hotspot in the graphite, drawing water up through the material’s pores, where it evaporates as steam. The brighter the light, the more steam is generated.The new material is able to convert 85 percent of incoming solar energy into steam — a significant improvement over recent approaches to solar-powered steam generation. What’s more, the setup loses very little heat in the process, and can produce steam at relatively low solar intensity. This would mean that, if scaled up, the setup would likely not require complex, costly systems to highly concentrate sunlight.Hadi Ghasemi, a postdoc in MIT’s Department of Mechanical Engineering, says the spongelike structure can be made from relatively inexpensive materials — a particular advantage for a variety of compact, steam-powered applications.”Steam is important for desalination, hygiene systems, and sterilization,” says Ghasemi, who led the development of the structure. “Especially in remote areas where the sun is the only source of energy, if you can generate steam with solar energy, it would be very useful.”Ghasemi and mechanical engineering department head Gang Chen, along with five others at MIT, report on the details of the new steam-generating structure in the journal Nature Communications.Cutting the optical concentrationToday, solar-powered steam generation involves vast fields of mirrors or lenses that concentrate incoming sunlight, heating large volumes of liquid to high enough temperatures to produce steam. However, these complex systems can experience significant heat loss, leading to inefficient steam generation.Recently, scientists have explored ways to improve the efficiency of solar-thermal harvesting by developing new solar receivers and by working with nanofluids. The latter approach involves mixing water with nanoparticles that heat up quickly when exposed to sunlight, vaporizing the surrounding water molecules as steam. But initiating this reaction requires very intense solar energy — about 1,000 times that of an average sunny day.By contrast, the MIT approach generates steam at a solar intensity about 10 times that of a sunny day — the lowest optical concentration reported thus far. …

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Changes in agriculture increase high river flow rates

Just as a leaky roof can make a house cooler and wetter when it’s raining as well as hotter and dryer when it’s sunny, changes in land use can affect river flow in both rainy and dry times, say two University of Iowa researchers.While it may be obvious that changes in river water discharge across the U.S. Midwest can be related to changes in rainfall and agricultural land use, it is important to learn how these two factors interact in order to get a better understanding of what the future may look like, says Gabriele Villarini, UI assistant professor of civil and environmental engineering, assistant research engineer at IIHR — Hydroscience & Engineering and lead author of a published research paper on the subject.”We wanted to know what the relative impacts of precipitation and agricultural practices played in shaping the discharge record that we see today,” he says. “Is it an either/or answer or a much more nuanced one?”By understanding our past we are better positioned in making meaningful statements about our future,” he says.The potential benefits of understanding river flow are especially great in the central United States, particularly Iowa, where spring and summer floods have hit the area in 1993, 2008, 2013 and 2014, interrupted by the drought of 2012. Large economic damage and even loss of life have resulted, says co-author Aaron Strong, UI assistant professor in the Department of Urban and Regional Planning and with the Environmental Policy Program at the UI Public Policy Center.”What is interesting to note,” says Strong, “is that the impacts, in terms of flooding, have been exacerbated. At the same time, the impacts of drought, for in-stream flow, have been mitigated with the changes in land use composition that we have seen over the last century.”In order to study the effect of changes in agricultural practices on Midwest river discharge, the researchers focused on Iowa’s Raccoon River at Van Meter, Iowa. The 9,000-square-kilometer watershed has the advantage of having had its water discharge levels measured and recorded daily for most of the 20th century right on up to the present day. (The study focused on the period 1927-2012). During that period, the number of acres used for corn and soybean production greatly increased, roughly doubling over the course of the 20th century.Not surprisingly, they found that variability in rainfall is responsible for most of the changes in water discharge volumes.However, the water discharge rates also varied with changes in agricultural practices, as defined by soybean and corn harvested acreage in the Raccoon River watershed. In times of flood and in times of drought, water flow rates were exacerbated by more or less agriculture, respectively. The authors suggest that although flood conditions may be exacerbated by increases in agricultural production, this concern “must all be balanced by the private concerns of increased revenue from agricultural production through increased cultivation.””Our results suggest that changes in agricultural practices over this watershed — with increasing acreage planted in corn and soybeans over time — translated into a seven-fold increase in rainfall contribution to the average annual maximum discharge when we compare the present to the 1930s,” Villarini says.The UI research paper, “Roles of climate and agricultural practices in discharge changes in an agricultural watershed in Iowa,” can be found in the April 15 online edition of Agriculture, Ecosystems & Environment.Story Source:The above story is based on materials provided by University of Iowa. …

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Roomy cages built from DNA could one day deliver drugs, devices

Move over, nanotechnologists, and make room for the biggest of the small. Scientists at the Harvard’s Wyss Institute have built a set of self-assembling DNA cages one-tenth as wide as a bacterium. The structures are some of the largest and most complex structures ever constructed solely from DNA, they report today’s online edition of Science.Moreover, the scientists visualized them using a DNA-based super-resolution microscopy method — and obtained the first sharp 3D optical images of intact synthetic DNA nanostructures in solution.In the future, scientists could potentially coat the DNA cages to enclose their contents, packaging drugs for delivery to tissues. And, like a roomy closet, the cage could be modified with chemical hooks that could be used to hang other components such as proteins or gold nanoparticles. This could help scientists build a variety of technologies, including tiny power plants, miniscule factories that produce specialty chemicals, or high-sensitivity photonic sensors that diagnose disease by detecting molecules produced by abnormal tissue.”I see exciting possibilities for this technology,” said Peng Yin, Ph.D., a Core Faculty member at the Wyss Institute and Assistant Professor of Systems Biology at Harvard Medical School, and senior author of the paper.Building with DNADNA is best known as a keeper of genetic information. But scientists in the emerging field of DNA nanotechnology are exploring ways to use it to build tiny structures for a variety of applications. These structures are programmable, in that scientists can specify the sequence of letters, or bases, in the DNA, and those sequences then determine the structure it creates.So far most researchers in the field have used a method called DNA origami, in which short strands of DNA staple two or three separate segments of a much longer strand together, causing that strand to fold into a precise shape. DNA origami was pioneered in part by Wyss Institute Core Faculty member William Shih, Ph.D., who is also an Associate Professor in the Department of Biological Chemistry and Molecular Pharmacology at Harvard Medical School and the Department of Cancer Biology at the Dana-Farber Cancer Institute.Yin’s team has built different types of DNA structures, including a modular set of parts called single-stranded DNA tiles or DNA bricks. Like LEGO bricks, these parts can be added or removed independently. Unlike LEGO bricks, they spontaneously self-assemble.But for some applications, scientists might need to build much larger DNA structures than anyone has built so far. …

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New wireless network to revolutionize soil testing

A University of Southampton researcher has helped to develop a wireless network of sensors that is set to revolutionize soil-based salinity measuring.Dr Nick Harris, from Electronics and Electrical Engineering, worked with a group of professors from the University of Western Australia (UWA) to produce the revolutionary sensor that can carry out non-destructive testing of soil samples.The sensor is capable of measuring the chloride (salt) in the soil moisture and linking up with other sensors to create a wireless network that can collate and relay the measurement readings. The network can also control the time intervals at which measurements are taken.The sensor is placed in the soil and measures the chloride levels in the soil moisture in a non-destructive way. These chloride levels make up a high proportion of the overall soil salinity.Dr Harris says: “Traditionally, soil-based measurements involve taking samples and transporting them to the laboratory for analysis. This is very labor and cost intensive and therefore it usually means spot checks only with samples being taken every two to three months. It also doesn’t differentiate between chloride in crystallized form and chloride in dissolved form. This can be an important difference as plants only ‘see’ chloride in the soil moisture.”The removal of a soil sample from its natural environment also means that the same sample can only be measured once, so the traditional (destructive) method is not suited to measuring changes at a point over a period of time..”The new sensors are connected to a small unit and can be ‘planted’ in the ground and left to their own devices. The limiting factor for lifetime is usually the sensor. However, these sensors are expected to have a lifetime in excess of one year. The battery-powered unit can transmit data and information by short range radio, Bluetooth, satellite or mobile phone network, as well as allowing data to be logged to a memory card to be collected later.The novel device allows up to seven sensors to be connected at a time to a single transmitter allowing multi-point measurements to be simply taken.Dr Harris adds: “These soil-based chloride sensors can benefit a wide range of applications. Large parts of the world have problems with salt causing agricultural land to be unusable, but the new sensors allow the level of salt to be measured in real time, rather than once every few months as was previously the case.”At plant level, probes can be positioned at continuous levels of depth to determine the salt concentration to which roots are exposed and whether this concentration changes with the depth of the soil or in different weather conditions. …

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Squeezing light into metals: Engineers control conductivity with inkjet printer

Using an inexpensive inkjet printer, University of Utah electrical engineers produced microscopic structures that use light in metals to carry information. This new technique, which controls electrical conductivity within such microstructures, could be used to rapidly fabricate superfast components in electronic devices, make wireless technology faster or print magnetic materials.The study appears online March 7 in the journal Advanced Optical Materials.High-speed Internet and other data-transfer techniques rely on light transported through optical fibers with very high bandwidth, which is a measure of how fast data can be transferred. Shrinking these fibers allows more data to be packed into less space, but there’s a catch: optical fibers hit a limit on how much data they can carry as light is squeezed into smaller and smaller spaces.In contrast, electronic circuits can be fashioned at much smaller sizes on silicon wafers. However, electronic data transfer operates at frequencies with much lower bandwidth, reducing the amount of data that can be carried.A recently discovered technology called plasmonics marries the best aspects of optical and electronic data transfer. By crowding light into metal structures with dimensions far smaller than its wavelength, data can be transmitted at much higher frequencies such as terahertz frequencies, which lie between microwaves and infrared light on the spectrum of electromagnetic radiation that also includes everything from X-rays to visible light to gamma rays. Metals such as silver and gold are particularly promising plasmonic materials because they enhance this crowding effect. “Very little well-developed technology exists to create terahertz plasmonic devices, which have the potential to make wireless devices such as Bluetooth — which operates at 2.4 gigahertz frequency — 1,000 times faster than they are today,” says Ajay Nahata, a University of Utah professor of electrical and computer engineering and senior author of the new study.Using a commercially available inkjet printer and two different color cartridges filled with silver and carbon ink, Nahata and his colleagues printed 10 different plasmonic structures with a periodic array of 2,500 holes with different sizes and spacing on a 2.5-inch-by-2.5 inch plastic sheet.The four arrays tested had holes 450 microns in diameter — about four times the width of a human hair — and spaced one-25th of an inch apart. Depending on the relative amounts of silver and carbon ink used, the researchers could control the plasmonic array’s electrical conductivity, or how efficient it was in carrying an electrical current.”Using a $60 inkjet printer, we have developed a low-cost, widely applicable way to make plasmonic materials,” Nahata says. “Because we can draw and print these structures exactly as we want them, our technique lets you make rapid changes to the plasmonic properties of the metal, without the million-dollar instrumentation typically used to fabricate these structures.”Plasmonic arrays are currently made using microfabrication techniques that require expensive equipment and manufacture only one array at a time. Until now, controlling conductivity in these arrays has proven extremely difficult for researchers.Nahata and his co-workers at the University of Utah’s College of Engineering used terahertz imaging to measure the effect of printed plasmonic arrays on a beam of light. …

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Bright pulses of light could make space veggies more nutritious

Exposing leafy vegetables grown during spaceflight to a few bright pulses of light daily could increase the amount of eye-protecting nutrients produced by the plants, according to a new study by researchers at the University of Colorado Boulder.One of the concerns for astronauts during future extended spaceflights will be the onslaught of eye-damaging radiation they’ll be exposed to. But astronauts should be able to mitigate radiation-induced harm to their eyes by eating plants that contain carotenoids, especially zeaxanthin, which is known to promote eye health.Zeaxanthin could be ingested as a supplement, but there is evidence that human bodies are better at absorbing carotenoids from whole foods, such as green leafy vegetables.Already, NASA has been studying ways to grow fresh produce during deep space missions to maintain crew morale and improve overall nutrition. Current research into space gardening tends to focus on getting the plants to grow as large as possible as quickly as possible by providing optimal light, water and fertilizer. But the conditions that are ideal for producing biomass are not necessarily ideal for the production of many nutrients, including zeaxanthin.”There is a trade-off,” said Barbara Demmig-Adams, professor of distinction in the Department of Ecology and Evolutionary Biology and a co-author of the study published in the journal Acta Astronautica. “When we pamper plants in the field, they produce a lot of biomass but they aren’t very nutritious. If they have to fend for themselves — if they have to defend themselves against pathogens or if there’s a little bit of physical stress in the environment — plants make defense compounds that help them survive. And those are the antioxidants that we need.”Plants produce zeaxanthin when their leaves are absorbing more sunlight than they can use, which tends to happen when the plants are stressed. For example, a lack of water might limit the plant’s ability to use all the sunlight it’s getting for photosynthesis. To keep the excess sunlight from damaging the plant’s biochemical pathways, it produces zeaxanthin, a compound that helps safely remove excess light.Zeaxanthin, which the human body cannot produce on its own, plays a similar protective role in our eyes.”Our eyes are like a leaf — they are both about collecting light,” Demmig-Adams said. “We need the same protection to keep us safe from intense light.”The CU-Boulder research team — which also included undergraduate researcher Elizabeth Lombardi, postdoctoral researcher Christopher Cohu and ecology and evolutionary biology Professor William Adams — set out to determine if they could find a way to “have the cake and eat it too” by simultaneously maximizing plant growth and zeaxanthin production.Using the model plant species Arabidopsis, the team demonstrated that a few pulses of bright light on a daily basis spurred the plants to begin making zeaxanthin in preparation for an expected excess of sunlight. …

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Herding robots: New system combines control programs so fleets of robots can collaborate

A new system combines simple control programs to enable fleets of robots — or other “multiagent systems” — to collaborate in unprecedented ways.Writing a program to control a single autonomous robot navigating an uncertain environment with an erratic communication link is hard enough; write one for multiple robots that may or may not have to work in tandem, depending on the task, is even harder.As a consequence, engineers designing control programs for “multiagent systems” — whether teams of robots or networks of devices with different functions — have generally restricted themselves to special cases, where reliable information about the environment can be assumed or a relatively simple collaborative task can be clearly specified in advance.This May, at the International Conference on Autonomous Agents and Multiagent Systems, researchers from MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) will present a new system that stitches existing control programs together to allow multiagent systems to collaborate in much more complex ways. The system factors in uncertainty — the odds, for instance, that a communication link will drop, or that a particular algorithm will inadvertently steer a robot into a dead end — and automatically plans around it.For small collaborative tasks, the system can guarantee that its combination of programs is optimal — that it will yield the best possible results, given the uncertainty of the environment and the limitations of the programs themselves.Working together with Jon How, the Richard Cockburn Maclaurin Professor of Aeronautics and Astronautics, and his student Chris Maynor, the researchers are currently testing their system in a simulation of a warehousing application, where teams of robots would be required to retrieve arbitrary objects from indeterminate locations, collaborating as needed to transport heavy loads. The simulations involve small groups of iRobot Creates, programmable robots that have the same chassis as the Roomba vacuum cleaner.Reasonable doubt”In [multiagent] systems, in general, in the real world, it’s very hard for them to communicate effectively,” says Christopher Amato, a postdoc in CSAIL and first author on the new paper. “If you have a camera, it’s impossible for the camera to be constantly streaming all of its information to all the other cameras. Similarly, robots are on networks that are imperfect, so it takes some amount of time to get messages to other robots, and maybe they can’t communicate in certain situations around obstacles.”An agent may not even have perfect information about its own location, Amato says — which aisle of the warehouse it’s actually in, for instance. Moreover, “When you try to make a decision, there’s some uncertainty about how that’s going to unfold,” he says. “Maybe you try to move in a certain direction, and there’s wind or wheel slippage, or there’s uncertainty across networks due to packet loss. So in these real-world domains with all this communication noise and uncertainty about what’s happening, it’s hard to make decisions.”The new MIT system, which Amato developed with co-authors Leslie Kaelbling, the Panasonic Professor of Computer Science and Engineering, and George Konidaris, a fellow postdoc, takes three inputs. One is a set of low-level control algorithms — which the MIT researchers refer to as “macro-actions” — which may govern agents’ behaviors collectively or individually. The second is a set of statistics about those programs’ execution in a particular environment. …

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Bats inspire ‘micro air vehicle’ designs: Small flying vehicles, complete with flapping wings, may now be designed

By exploring how creatures in nature are able to fly by flapping their wings, Virginia Tech researchers hope to apply that knowledge toward designing small flying vehicles known as “micro air vehicles” with flapping wings.More than 1,000 species of bats have hand membrane wings, meaning that their fingers are essentially “webbed” and connected by a flexible membrane. But understanding how bats use their wings to manipulate the air around them is extremely challenging — primarily because both experimental measurements on live creatures and the related computer analysis are quite complex.In Virginia Tech’s study of fruit bat wings, the researchers used experimental measurements of the movements of the bats’ wings in real flight, and then used analysis software to see the direct relationship between wing motion and airflow around the bat wing. They report their findings in the journal Physics of Fluids.”Bats have different wing shapes and sizes, depending on their evolutionary function. Typically, bats are very agile and can change their flight path very quickly — showing high maneuverability for midflight prey capture, so it’s of interest to know how they do this,” explained Danesh Tafti, the William S. Cross professor in the Department of Mechanical Engineering and director of the High Performance Computational Fluid Thermal Science and Engineering Lab at Virginia Tech.To give you an idea of the size of a fruit bat, it weighs roughly 30 grams and a single fully extended wing is about 17 x 9 cm in length, according to Tafti.Among the biggest surprises in store for the researchers was how bat wings manipulated the wing motion with correct timing to maximize the forces generated by the wing. “It distorts its wing shape and size continuously during flapping,” Tafti noted.For example, it increases the area of the wing by about 30 percent to maximize favorable forces during the downward movement of the wing, and it decreases the area by a similar amount on the way up to minimize unfavorable forces. The force coefficients generated by the wing are “about two to three times greater than a static airfoil wing used for large airplanes,” said Kamal Viswanath, a co-author who was a graduate research assistant working with Tafti when the work was performed and is now a research engineer at the U.S. Naval Research Lab’s Laboratories for Computational Physics and Fluid Dynamics.This study was just an initial step in the researchers’ work. “Next, we’d like to explore deconstructing the seemingly complex motion of the bat wing into simpler motions, which is necessary to make a bat-inspired flying robot,” said Viswanath. The researchers also want to keep the wing motion as simple as possible, but with the same force production as that of a real bat.”We’d also like to explore other bat wing motions, such as a bat in level flight or a bat trying to maneuver quickly to answer questions, including: What are the differences in wing motion and how do they translate to air movement and forces that the bat generates? …

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Researchers hijack cancer migration mechanism to ‘move’ brain tumors

One factor that makes glioblastoma cancers so difficult to treat is that malignant cells from the tumors spread throughout the brain by following nerve fibers and blood vessels to invade new locations. Now, researchers have learned to hijack this migratory mechanism, turning it against the cancer by using a film of nanofibers thinner than human hair to lure tumor cells away.Instead of invading new areas, the migrating cells latch onto the specially-designed nanofibers and follow them to a location — potentially outside the brain — where they can be captured and killed. Using this technique, researchers can partially move tumors from inoperable locations to more accessible ones. Though it won’t eliminate the cancer, the new technique reduced the size of brain tumors in animal models, suggesting that this form of brain cancer might one day be treated more like a chronic disease.”We have designed a polymer thin film nanofiber that mimics the structure of nerves and blood vessels that brain tumor cells normally use to invade other parts of the brain,” explained Ravi Bellamkonda, lead investigator and chair of the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University. “The cancer cells normally latch onto these natural structures and ride them like a monorail to other parts of the brain. By providing an attractive alternative fiber, we can efficiently move the tumors along a different path to a destination that we choose.”Details of the technique were reported February 16 in the journal Nature Materials. The research was supported by the National Cancer Institute (NCI), part of the National Institutes of Health; by Atlanta-based Ian’s Friends Foundation, and by the Georgia Research Alliance. In addition to the Coulter Department of Biomedical Engineering, the research team included Children’s Healthcare of Atlanta and Emory University.Treating the Glioblastoma multiforme cancer, also known as GBM, is difficult because the aggressive and invasive cancer often develops in parts of the brain where surgeons are reluctant to operate. Even if the primary tumor can be removed, however, it has often spread to other locations before being diagnosed.New drugs are being developed to attack GBM, but the Atlanta-based researchers decided to take a more engineering approach. …

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Optimizing donor kidney distribution in the United States

Northwestern University’s Sanjay Mehrotra has developed an innovative model that could help ease kidney distribution inequities among regions in the U.S. and ultimately help save hundreds of lives. His mathematical model, which takes into account a number of different factors, simulates and optimizes donor kidney distribution.Mehrotra will discuss his research in a presentation titled “Addressing Allocation Inefficiencies and Geographic Disparities” at the American Association for the Advancement of Science (AAAS) annual meeting in Chicago. His presentation is part of a symposium titled “Transplant Organ Shortage: Informing National Policies Using Management Sciences” to be held from 10 to 11:30 a.m. CST Friday, Feb. 14, in Columbus IJ of the Hyatt Regency Chicago.Mehrotra also will participate in a press briefing to be held at 1 p.m. CST the same day in Vevey Room 3 of the Swisstel Chicago.In addition to Mehrotra, two other Northwestern professors will discuss issues related to organ shortage during both the symposium and press briefing.Michael Abecassis, M.D., chief of the division of organ transplantation and founding director of the Comprehensive Transplant Center at Northwestern University Feinberg School of Medicine, will offer a brief overview of the current issues facing organ allocation.John Friedewald, M.D., associate professor in medicine and surgery at Feinberg and director of clinical research at Northwestern University Feinberg School of Medicine Comprehensive Transplant Center and transplant nephrologist at Northwestern Memorial Hospital, will speak about policy changes in kidney allocation that were developed during his recent term as chair of the United Network for Organ Sharing Kidney Transplantation Committee.Nearly 100,000 people in the United States are waiting for kidney transplants, but only 17,000 kidneys are available annually from both living and deceased donors. There are major regional inequalities in access to organs because of supply and demand disparities among different areas of the country. A person in one state might get a kidney within a year, while someone in another state might wait up to four years. As a consequence, nearly 5,000 people die each year waiting for a kidney transplant.Logistically, organ allocation is a difficult problem. …

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Paclitaxel Nanoparticles to Treat Late Stage Peritoneal Mesothelioma

A group of graduate students and postdoctoral fellows at Boston Universityare trying to find a better treatment for late-stage peritoneal mesothelioma. The group is developing a method to deliver chemotherapy drugs directly to tumor cells withnanoparticleswhich are absorbed by the tumor cells and release the drugs. The detailedstudypublished February 4, on the BU College of Engineering site is part of a four part series detailing current research projects being performed bytheGrinstaff Group.The Grinstaff Group chose to focus on peritoneal mesothelioma because it is easier to isolate and does not metastasize like other cancers, theoretically making it easier to attack with an innovative drug delivery system, in this case – nanoparticles loaded with paclitaxel, a chemotherapy drug commonly used to treat mesothelioma.The nanoparticles are composed of squiggly …

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Cochlear implant with no exterior hardware can be wirelessly recharged

Cochlear implants — medical devices that electrically stimulate the auditory nerve — have granted at least limited hearing to hundreds of thousands of people worldwide who otherwise would be totally deaf. Existing versions of the device, however, require that a disk-shaped transmitter about an inch in diameter be affixed to the skull, with a wire snaking down to a joint microphone and power source that looks like an oversized hearing aid around the patient’s ear.Researchers at MIT’s Microsystems Technology Laboratory (MTL), together with physicians from Harvard Medical School and the Massachusetts Eye and Ear Infirmary (MEEI), have developed a new, low-power signal-processing chip that could lead to a cochlear implant that requires no external hardware. The implant would be wirelessly recharged and would run for about eight hours on each charge.The researchers describe their chip in a paper they’re presenting this week at the International Solid-State Circuits Conference. The paper’s lead author — Marcus Yip, who completed his PhD at MIT last fall — and his colleagues Rui Jin and Nathan Ickes, both in MIT’s Department of Electrical Engineering and Computer Science, will also exhibit a prototype charger that plugs into an ordinary cell phone and can recharge the signal-processing chip in roughly two minutes.”The idea with this design is that you could use a phone, with an adaptor, to charge the cochlear implant, so you don’t have to be plugged in,” says Anantha Chandrakasan, the Joseph F. and Nancy P. Keithley Professor of Electrical Engineering and corresponding author on the new paper. “Or you could imagine a smart pillow, so you charge overnight, and the next day, it just functions.”Adaptive reuseExisting cochlear implants use an external microphone to gather sound, but the new implant would instead use the natural microphone of the middle ear, which is almost always intact in cochlear-implant patients.The researchers’ design exploits the mechanism of a different type of medical device, known as a middle-ear implant. Delicate bones in the middle ear, known as ossicles, convey the vibrations of the eardrum to the cochlea, the small, spiral chamber in the inner ear that converts acoustic signals to electrical. In patients with middle-ear implants, the cochlea is functional, but one of the ossicles — the stapes — doesn’t vibrate with enough force to stimulate the auditory nerve. A middle-ear implant consists of a tiny sensor that detects the ossicles’ vibrations and an actuator that helps drive the stapes accordingly.The new device would use the same type of sensor, but the signal it generates would travel to a microchip implanted in the ear, which would convert it to an electrical signal and pass it on to an electrode in the cochlea. …

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New microchip demonstrates how metastasis takes place

Nearly 70 percent of patients with advanced breast cancer experience skeletal metastasis, in which cancer cells migrate from a primary tumor into bone — a painful development that can cause fractures and spinal compression. While scientists are attempting to better understand metastasis in general, not much is known about how and why certain cancers spread to specific organs, such as bone, liver, and lungs.Now researchers from MIT, Italy, and South Korea have developed a three-dimensional microfluidic platform that mimics the spread of breast cancer cells into a bonelike environment.The microchip — slightly larger than a dime — contains several channels in which the researchers grew endothelial cells and bone cells to mimic a blood vessel and bone side-by-side. They then injected a highly metastatic line of breast cancer cells into the fabricated blood vessel.Twenty-four hours later, the team observed that twice as many cancer cells had made their way through the vessel wall and into the bonelike environment than had migrated into a simple collagen-gel matrix. Moreover, the cells that made it through the vessel lining and into the bonelike setting formed microclusters of up to 60 cancer cells by the experiment’s fifth day.”You can see how rapidly they are growing,” says Jessie Jeon, a graduate student in mechanical engineering. “We only waited until day five, but if we had gone longer, [the size of the clusters] would have been overwhelming.”The team also identified two molecules that appear to encourage cancer cells to metastasize: CXCL5, a protein ligand secreted by bone cells, and CXCR2, a receptor protein on cancer cells that binds to the ligand. The preliminary results suggest that these molecules may be potential targets to reduce the spread of cancer.Jeon says the experiments demonstrate that the microchip may be used in the future to test drugs that might stem metastasis, and also as a platform for studying cancer’s spread to other organs.She and her colleagues, including Roger Kamm, the Cecil and Ida Green Distinguished Professor of Mechanical and Biological Engineering at MIT, have outlined the results of their experiments in the journal Biomaterials.”Currently, we don’t understand why certain cancers preferentially metastasize to specific organs,” Kamm says. “An example is that breast cancer will form metastatic tumors in bone, but not, for example, muscle. Why is this, and what factors determine it? We can use our model system both to understand this selectivity, and also to screen for drugs that might prevent it.”Through a wall and into boneThe process by which cancer cells form secondary tumors requires the cells to first survive a journey through the circulatory system. These migrating cells attach to a blood vessel’s inner lining, and ultimately squeeze through to the surrounding tissue — a process called extravasation, which Kamm’s research group modeled last fall using a novel microfluidic platform.Now the group is looking to the next step in metastasis: the stage at which a cancer cell invades a specific organ. …

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Integration brings quantum computer a step closer

An international research group of scientists and engineers led by the University of Bristol, UK, has made an important advance towards a quantum computer by shrinking down key components and integrating them onto a silicon microchip.Scientists and engineers from an international collaboration led by Dr Mark Thompson from the University of Bristol have, for the first time, generated and manipulated single particles of light (photons) on a silicon chip — a major step forward in the race to build a quantum computer.Quantum computers and quantum technologies in general are widely anticipated as the next major technology advancement, and are poised to replace conventional information and computing devices in applications ranging from ultra-secure communications and high-precision sensing to immensely powerful computers. Quantum computers themselves will likely lead to breakthroughs in the design of new materials and in the discovery of new medical drugs.Whilst still in their infancy, quantum technologies are making rapid process, and a revolutionary new approach pioneered by the University of Bristol is exploiting state-of-the-art engineering processes and principles to make leaps and bounds in a field previously dominated by scientists.Featuring on the front cover of Nature Photonics, this latest advancement is one of the important pieces in the jigsaw needed in order to realise a quantum computer. While previous attempts have required external light sources to generate the photons, this new chip integrates components that can generate photons inside the chip.”We were surprised by how well the integrated sources performed together,” admits Joshua Silverstone, lead author of the paper. “They produced high-quality identical photons in a reproducible way, confirming that we could one day manufacture a silicon chip with hundreds of similar sources on it, all working together. This could eventually lead to an optical quantum computer capable of performing enormously complex calculations.”Group leader Mark Thompson explained: “Single-photon detectors, sources and circuits have all been developed separately in silicon but putting them all together and integrating them on a chip is a huge challenge. Our device is the most functionally complex photonic quantum circuit to date, and was fabricated by Toshiba using exactly the same manufacturing techniques used to make conventional electronic devices. We can generate and manipulate quantum entanglement all within a single mm-sized micro-chip.”The group, which, includes researchers from Toshiba Corporation (Japan), Stanford University (US), University of Glasgow (UK) and TU Delft (The Netherlands), now plans to integrate the remaining necessary components onto a chip, and show that large-scale quantum devices using photons are possible.”Our group has been making steady progress towards a functioning quantum computer over the last five years,” said Thompson. “We hope to have within the next couple of years, photon-based devices complex enough to rival modern computing hardware for highly-specialised tasks.”However, these are just the first steps. To realise useful quantum machines will required a new breed of engineering — quantum engineers, individuals capable of understanding the fundamentals of quantum mechanics and applying this knowledge to real world problems.Bristol’s newly established Centre for Doctoral Training in Quantum Engineering will train a new generation of engineers, scientists and entrepreneurs to harness the power of quantum mechanics and lead the quantum technology revolution. This innovative centre bridges the gaps between physics, engineering, mathematics and computer science, working closely with chemists and biologists while interacting strongly with industry.Story Source:The above story is based on materials provided by University of Bristol. …

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What’s behind a #1 ranking? Open-source LineUp software enables granular analysis of subjective ranking systems

Behind every “Top 100” list are a generous sprinkling of personal bias and subjective decisions. Lacking the tools to calculate how factors like median home prices and crime rates actually affect the “best places to live,” the public must take experts’ analysis at face value.To shed light on the trustworthiness of rankings, Harvard researchers have created LineUp, an open-source application that empowers ordinary citizens to make quick, easy judgments about rankings based on multiple attributes.”It liberates people,” says Alexander Lex, a postdoctoral researcher at the Harvard School of Engineering and Applied Sciences (SEAS). “Imagine if a magazine published a ranking of ‘best restaurants.’ With this tool, we don’t have to rely on the editors’ skewed or specific perceptions. Everybody on the Internet can go there and see what’s really in the data and what part is personal opinion.”The first dynamic visualization software of its kind, LineUp allows users to assign weights to different parameters to create a custom ranking. For example, users might look at the raw data behind university rankings and decide for themselves the relative importance of student-faculty ratios or the number of citations per faculty member.So intuitive and powerful is LineUp, that its creators — Lex; his adviser Hanspeter Pfister, An Wang Professor of Computer Science at SEAS; Nils Gehlenborg, a research associate at Harvard Medical School; and Marc Streit and Samuel Gratzl at Johannes Kepler University in Linz — earned the best paper award at the IEEE Information Visualization (InfoVis) conference in October 2013.LineUp is part of a larger software package called Caleydo, an open-source visualization framework developed at Harvard, Johannes Kepler University, and Graz University of Technology. Caleydo visualizes genetic data and biological pathways — for example, to analyze and characterize cancer subtypes.”LineUp really was developed to address our need to understand the ranking of genes by mutation frequency and other clinical parameters in a group of patients,” explains Pfister. “It is an ideal tool to create and visualize complex combined scores of bioinformatics algorithms.””We started thinking about how we can make this easy for biologists to understand and how we can tell them what the most important parts of the dataset are,” says Lex.While LineUp is still being applied to formal genetic research, the group has chosen to also apply their work to simpler, more familiar ranking problems — for example, the healthiness of different foods, best employers, or the best places to live.LineUp introduces a dynamic element to the static analysis usually done on an Excel spreadsheet. It allows the user to immediately consider or ignore columns in a dataset by simply dragging them into or out of the window. It also enables side-by-side comparisons of alternative weighting systems.And of course, not all metrics contribute to an item’s rank the same way. Higher values of some metrics imply a higher rank, but not in all cases. …

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To hear without being heard: First nonreciprocal acoustic circulator created

A team of researchers at The University of Texas at Austin’s Cockrell School of Engineering has built the first-ever circulator for sound. The team’s experiments successfully prove that the fundamental symmetry with which acoustic waves travel through air between two points in space (“if you can hear, you can also be heard”) can be broken by a compact and simple device.”Using the proposed concept, we were able to create one-way communication for sound traveling through air,” said Andrea Al, who led the project and is an associate professor and David & Doris Lybarger Endowed Faculty Fellow in the Cockrell School’s Department of Electrical and Computer Engineering. “Imagine being able to listen without having to worry about being heard in return.”This successful experiment is described in “Sound Isolation and Giant Linear Nonreciprocity in a Compact Acoustic Circulator,” which will be featured on the cover of Science in the Jan. 31 issue.An electronic circulator, typically used in communication devices and radars, is a nonreciprocal three-port device in which microwaves or radio signals are transmitted from one port to the next in a sequential way. When one of the ports is not used, the circulator acts as an isolator, allowing signals to flow from one port to the other, but not back. The UT Austin team realized the same functionality is true for sound waves traveling in air, which led to the team’s building of a first-of-its-kind three-port acoustic circulator.Romain Fleury, the paper’s first author and a Ph.D. student in Al’s group, said the circulator “is basically a one-way road for sound. The circulator can transmit acoustic waves in one direction but block them in the other, in a linear and distortion-free way.”The scientific knowledge gained from successfully building a nonreciprocal sound circulator may lead to advances in noise control, new acoustic equipment for sonars and sound communication systems, and improved compact components for acoustic imaging and sensing.”More broadly, our paper proves a new physical mechanism to break time-reversal symmetry and subsequently induce nonreciprocal transmission of waves, opening important possibilities beyond applications in acoustics,” Al said. “Using the same concept, it may actually be possible to construct simpler, smaller and cheaper electronic circulators and other electronic components for wireless devices, as well as to create one-way communication channels for light.”This research may eventually allow for an “acoustical version of one-way glass,” said Preston Wilson, acoustics expert and associate professor in the Department of Mechanical Engineering. “It also opens up avenues for very efficient sound isolation and interesting new concepts for active control of sound isolators.”At the core of the team’s sound circulator is a resonant ring cavity loaded with three small computer fans that circulate the airflow at a specific velocity. …

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Eye contact builds bedside trust

Oct. 16, 2013 — Doctors who make a lot of eye contact are viewed as more likable and empathetic by patients, according to a new Northwestern Medicine study.Patients also gave doctors higher empathy scores when their total visit length was longer and when doctors engaged in a few “social touches” such as a handshake or pat on the back. However, more than three social touches in one visit decreased empathy scores. The researchers said it’s possible that too many social touches from a doctor may seem forced and not genuine to a patient.The study, published in the Journal of Participatory Medicine, analyzed videotaped doctors’ visits and reinforces the notion that nonverbal social communication is an important part of doctor/patient relationships that should be thoughtfully managed, especially as more technology and “screen time” is introduced into doctors’ offices.”The goal is to one day engineer systems and technologies that encourage the right amount of physician eye contact and other non-verbal social communication,” said Enid Montague, first author of the study. “As we collect more data we can build models that tell us exactly how much eye contact is needed to help patients trust and connect with a doctor, and design tools and technology that help doctors stay connected to patients.”Montague is an assistant professor in medicine, general internal medicine and geriatrics at Northwestern University Feinberg School of Medicine and an assistant professor in the McCormick School of Engineering and Applied Sciences.The researchers collected data from 110 first-time encounters between patients with common cold symptoms and primary care doctors. All of the doctors used paper charts and spent an average of 3 minutes and 38 seconds with each patient. After each visit, patient participants completed questionnaires to measure their perception of their doctor’s empathy, connectedness with the doctor and how much they liked their doctor.The visits were videotaped and researchers analyzed the recordings second-by-second, documenting what each person was doing, paying special attention to non-verbal communication. The researchers purposely chose to study doctors who used paper charts so they could develop a baseline for nonverbal communication activities without the presence of computerized systems.”Previous studies have found that nonverbal communication is important based on patient feedback, but this is one of the few that have looked at these things more broadly quantitatively,” Montague said. “We rigorously looked at what was happening at every point in time, so we validated a lot of the qualitative studies.”They concluded that while social touch and length of visit can play a role in a patient’s perception of doctor empathy, the amount of eye contact the doctor made was the most important factor for patients.”Simple things such as eye contact can have a big impact on our healthcare system as a whole,” Montague said. “If patients feel like their doctors aren’t being empathetic, then we are more likely to see patients who aren’t returning to care, who aren’t adhering to medical advice, who aren’t seeking care, who aren’t staying with the same providers. …

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Yoga accessible for the blind with new kinect-based program

Oct. 17, 2013 — In a typical yoga class, students watch an instructor to learn how to properly hold a position. But for people who are blind or can’t see well, it can be frustrating to participate in these types of exercises.Now, a team of University of Washington computer scientists has created a software program that watches a user’s movements and gives spoken feedback on what to change to accurately complete a yoga pose.”My hope for this technology is for people who are blind or low-vision to be able to try it out, and help give a basic understanding of yoga in a more comfortable setting,” said project lead Kyle Rector, a UW doctoral student in computer science and engineering.The program, called Eyes-Free Yoga, uses Microsoft Kinect software to track body movements and offer auditory feedback in real time for six yoga poses, including Warrior I and II, Tree and Chair poses. Rector and her collaborators published their methodology in the conference proceedings of the Association for Computing Machinery’s SIGACCESS International Conference on Computers and Accessibility in Bellevue, Wash., Oct. 21-23.Rector wrote programming code that instructs the Kinect to read a user’s body angles, then gives verbal feedback on how to adjust his or her arms, legs, neck or back to complete the pose. For example, the program might say: “Rotate your shoulders left,” or “Lean sideways toward your left.”The result is an accessible yoga “exergame” — a video game used for exercise — that allows people without sight to interact verbally with a simulated yoga instructor. Rector and collaborators Julie Kientz, a UW assistant professor in Computer Science & Engineering and in Human Centered Design & Engineering, and Cynthia Bennett, a research assistant in computer science and engineering, believe this can transform a typically visual activity into something that blind people can also enjoy.”I see this as a good way of helping people who may not know much about yoga to try something on their own and feel comfortable and confident doing it,” Kientz said. “We hope this acts as a gateway to encouraging people with visual impairments to try exercise on a broader scale.”Each of the six poses has about 30 different commands for improvement based on a dozen rules deemed essential for each yoga position. Rector worked with a number of yoga instructors to put together the criteria for reaching the correct alignment in each pose. The Kinect first checks a person’s core and suggests alignment changes, then moves to the head and neck area, and finally the arms and legs. …

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Finding blood clots before they wreak havoc

Oct. 16, 2013 — Life-threatening blood clots can form in anyone who sits on a plane for a long time, is confined to bed while recovering from surgery, or takes certain medications.There is no fast and easy way to diagnose these clots, which often remain undetected until they break free and cause a stroke or heart attack. However, new technology from MIT may soon change that: A team of engineers has developed a way to detect blood clots using a simple urine test.The noninvasive diagnostic, described in a recent issue of the journal ACS Nano, relies on nanoparticles that detect the presence of thrombin, a key blood-clotting factor.Such a system could be used to monitor patients who are at high risk for blood clots, says Sangeeta Bhatia, senior author of the paper and the John and Dorothy Wilson Professor of Biochemistry.”Some patients are at more risk for clotting, but existing blood tests are not consistently able to detect the formation of new clots,” says Bhatia, who is also a senior associate member of the Broad Institute and a member of MIT’s Koch Institute for Integrative Cancer Research and Institute for Medical Engineering and Science (IMES).Lead authors of the paper are Kevin Lin, a graduate student in chemical engineering, and Gabriel Kwong, a postdoc in IMES. Other authors are Andrew Warren, a graduate student in Health Sciences and Technology (HST), and former HST postdoc David Wood.Sensing thrombinBlood clotting is produced by a complex cascade of protein interactions, culminating in the formation of fibrin, a fibrous protein that seals wounds. The last step of this process — the conversion of fibrinogen to fibrin — is controlled by an enzyme called thrombin.Current tests for blood clotting are very indirect, Bhatia says. One, known as the D-dimer test, looks for the presence of fibrin byproducts, which indicates that a clot is being broken down, but will not detect its initial formation.Bhatia and her colleagues developed their new test based on a technology they first reported last year for early detection of colorectal cancer. “We realized the same exact technology would work for blood clots,” she says. “So we took the test we had developed before, which is an injectable nanoparticle, and made it a thrombin sensor.”The system consists of iron oxide nanoparticles, which the Food and Drug Administration has approved for human use, coated with peptides (short proteins) that are specialized to interact with thrombin. After being injected into mice, the nanoparticles travel throughout the body. When the particles encounter thrombin, the thrombin cleaves the peptides at a specific location, releasing fragments that are then excreted in the animals’ urine.Once the urine is collected, the protein fragments can be identified by treating the sample with antibodies specific to peptide tags included in the fragments. …

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Carbon’s new champion: Carbyne, a simple chain of carbon atoms, strongest material of all?

Oct. 9, 2013 — Carbyne will be the strongest of a new class of microscopic materials if and when anyone can make it in bulk.If they do, they’ll find carbyne nanorods or nanoropes have a host of remarkable and useful properties, as described in a new paper by Rice University theoretical physicist Boris Yakobson and his group. The paper appears this week in the American Chemical Society journal ACS Nano.Carbyne is a chain of carbon atoms held together by either double or alternating single and triple atomic bonds. That makes it a true one-dimensional material, unlike atom-thin sheets of graphene that have a top and a bottom or hollow nanotubes that have an inside and outside.According to the portrait drawn from calculations by Yakobson and his group:* Carbyne’s tensile strength — the ability to withstand stretching — surpasses “that of any other known material” and is double that of graphene. (Scientists had already calculated it would take an elephant on a pencil to break through a sheet of graphene.)* It has twice the tensile stiffness of graphene and carbon nanotubes and nearly three times that of diamond.* Stretching carbyne as little as 10 percent alters its electronic band gap significantly.* If outfitted with molecular handles at the ends, it can also be twisted to alter its band gap. With a 90-degree end-to-end rotation, it becomes a magnetic semiconductor.* Carbyne chains can take on side molecules that may make the chains suitable for energy storage.* The material is stable at room temperature, largely resisting crosslinks with nearby chains.That’s a remarkable set of qualities for a simple string of carbon atoms, Yakobson said.”You could look at it as an ultimately thin graphene ribbon, reduced to just one atom, or an ultimately thin nanotube,” he said. It could be useful for nanomechanical systems, in spintronic devices, as sensors, as strong and light materials for mechanical applications or for energy storage.”Regardless of the applications,” he said, “academically, it’s very exciting to know the strongest possible assembly of atoms.”Based on the calculations, he said carbyne might be the highest energy state for stable carbon. “People usually look for what is called the ‘ground state,’ the lowest possible energy configuration for atoms,” Yakobson said. “For carbon, that would be graphite, followed by diamond, then nanotubes, then fullerenes. But nobody asks about the highest energy configuration. …

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