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The recent election in Uttar Pradesh, India's largest state, gave Prime Minister Narendra Modi and his Bharatiya Janata Party a strong mandate, providing the government with a golden opportunity to advance economic development there, while reaching out to the Muslim population. But Modi seems intent on fueling Hindu chauvinism.
MIT researchers have designed a radical new method of creating flexible, printable electronics that combine sensors and processing circuitry.
Covering a robot — or an airplane or a bridge, for example — with sensors will require a technology that is both flexible and cost-effective to manufacture in bulk. To demonstrate the feasibility of their new method, the researchers at MIT’s Computer Science and Artificial Intelligence Laboratory have designed and built a 3D-printed device that responds to mechanical stresses by changing the color of a spot on its surface.
“In nature, networks of sensors and interconnects [such as the human nervous system] are called sensorimotor pathways,” says Subramanian Sundaram, an MIT graduate student in electrical engineering and computer science (EECS), who led the project. “We were trying to see whether we could replicate sensorimotor pathways inside a 3-D-printed object. So we considered the simplest organism we could find” — the golden tortoise beetle, or “goldbug,” an insect whose exterior usually appears golden but turns reddish orange if the insect is poked or prodded, that is, mechanically stressed.
The researchers present their new design in the latest issue of the journal Advanced Materials Technologies.
The key innovation was to 3D-print directly on the plastic substrate (support structure) instead of placing components on top. That greatly increases the range of devices that can be created; a printed substrate could consist of many materials, interlocked in intricate but regular patterns, which broadens the range of functional materials that printable electronics can use.*
Printed substrates also open the possibility of devices that, although printed as flat sheets, can fold themselves up into more complex, three-dimensional shapes. Printable robots that spontaneously self-assemble when heated, for instance (see “Self-assembling printable robotic components“), are a topic of ongoing research at the CSAIL Distributed Robotics Laboratory, led by Daniela Rus, the Andrew and Erna Viterbi Professor of Electrical Engineering and Computer Science at MIT.
3D-printed sensory composite
The MIT researchers’ new device is approximately T-shaped, but with a wide, squat base and an elongated crossbar. The crossbar is made from an elastic plastic, with a strip of silver running its length; in the researchers’ experiments, electrodes were connected to the crossbar’s ends. The base of the T is made from a more rigid plastic. It includes two printed transistors and what the researchers call a “pixel,” a circle of semiconducting polymer whose color changes when the crossbars stretch, modifying the electrical resistance of the silver strip.**
A transistor consists of semiconductor channel on top of which sits a “gate,” a metal wire that, when charged, generates an electric field that switches the semiconductor between its electrically conductive and nonconductive states. In a standard transistor, there’s an insulator between the gate and the semiconductor, to prevent the gate current from leaking into the semiconductor channel.
The transistors in the MIT researchers’ device instead separate the gate and the semiconductor with an electrolyte — a layer of water containing potassium chloride mixed with glycerol. Charging the gate drives potassium ions into the semiconductor, changing its conductivity.***
“I am very impressed with both the concept and the realization of the system,” says Hagen Klauk, who leads the Organic Electronic Research Group at the Max Planck Institute for Solid State Research, in Stuttgart, Germany. “The approach of printing an entire optoelectronic system — including the substrate and all the components — by depositing all the materials, including solids and liquids, by 3-D printing is certainly novel, interesting, and useful, and the demonstration of the functional system confirms that the approach is also doable. By fabricating the substrate on the fly, the approach is particularly useful for improvised manufacturing environments where dedicated substrate materials may not be available.”
The work was supported by the DARPA SIMPLEX program through SPAWAR.
* To build the device, the researchers used the MultiFab, a custom 3-D printer developed MIT. The MultiFab already included two different “print heads,” one for emitting hot materials and one for cool, and an array of ultraviolet light-emitting diodes. Using ultraviolet radiation to “cure” fluids deposited by the print heads produces the device’s substrate.
** Sundaram added a copper-and-ceramic heater, which was necessary to deposit the semiconducting plastic: The plastic is suspended in a fluid that’s sprayed onto the device surface, and the heater evaporates the fluid, leaving behind a layer of plastic only 200 nanometers thick. The layer of saltwater lowers the device’s operational voltage, so that it can be powered with an ordinary 1.5-volt battery.
*** But it does render the device less durable. “I think we can probably get it to work stably for two months, maybe,” Sundaram says. “One option is to replace that liquid with something between a solid and a liquid, like a hydrogel, perhaps. But that’s something we would work on later. This is an initial demonstration.”
A method for 3D-printing autonomous sensory composites requiring no external processing is presented. The composite operates at 1.5 V, locally performs active signal transduction with embedded electrical gain, and responds to stimuli, reversibly transducing mechanical strain into a transparency change. Digital assembly of spatially tailored solids and thin films, with encapsulated liquids, provides a route for realizing complex autonomous systems.
European Union heads of state just gathered to celebrate the 60th anniversary of the signing of the Treaty of Rome, while right-wing populists are threatening to destroy Europe’s open liberal societies. Although the Dutch election showed that such forces can be defeated, the risk of another populist upset remains real.
On March 27, the United Nations will start negotiations on an international treaty to ban nuclear weapons. The nuclear weapon states will finally be put to the test: Will they keep their promises to disarm and join the treaty, or will they reject international law and the will of the global community?
A Mayo Clinic study says the best training for adults is high-intensity aerobic exercise, which they believe can reverse some cellular aspects of aging.
Mayo researchers compared 12 weeks of high-intensity interval training (workouts in which you alternate periods of high-intensity exercise with low-intensity recovery periods), resistance training, and combined training. While all three enhanced insulin sensitivity and lean mass, only high-intensity interval training and combined training improved aerobic capacity and skeletal muscle mitochondrial respiration. (Decline in mitochondrial content and function are common in older adults.)
High-intensity intervals also improved muscle protein content, which enhanced energetic functions and also caused muscle enlargement, especially in older adults. The researchers said exercise training significantly enhanced the cellular machinery responsible for making new proteins. That contributes to protein synthesis, thus reversing a major adverse effect of aging.
“We encourage everyone to exercise regularly, but the take-home message for aging adults is that supervised high-intensity training is probably best, because, both metabolically and at the molecular level, it confers the most benefits,” says K. Sreekumaran Nair, M.D., Ph.D., a Mayo Clinic endocrinologist and senior researcher on the study.
He says the high-intensity training reversed some manifestations of aging in the body’s protein function, but noted that increasing muscle strength requires resistance training a couple of days a week.
In the study, researchers tracked metabolic and molecular changes in a group of young and older adults over 12 weeks, gathering data 72 hours after individuals in randomized groups completed each type of exercise. General findings showed:
The research findings appear in Cell Metabolism. The research was supported by the National Institutes of Health, Mayo Clinic, the Robert and Arlene Kogod Center on Aging, and the Murdock-Dole Professorship.
The molecular transducers of benefits from different exercise modalities remain incompletely defined. Here we report that 12 weeks of high-intensity aerobic interval (HIIT), resistance (RT), and combined exercise training enhanced insulin sensitivity and lean mass, but only HIIT and combined training improved aerobic capacity and skeletal muscle mitochondrial respiration. HIIT revealed a more robust increase in gene transcripts than other exercise modalities, particularly in older adults, although little overlap with corresponding individual protein abundance was noted. HIIT reversed many age-related differences in the proteome, particularly of mitochondrial proteins in concert with increased mitochondrial protein synthesis. Both RT and HIIT enhanced proteins involved in translational machinery irrespective of age. Only small changes of methylation of DNA promoter regions were observed. We provide evidence for predominant exercise regulation at the translational level, enhancing translational capacity and proteome abundance to explain phenotypic gains in muscle mitochondrial function and hypertrophy in all ages.
After the Paris climate agreement, efforts to combat corruption and global warming must go hand in hand. Corruption ensures that moneyed and powerful interests are free from rules that hold them in check, and it explains why governments have so far fallen short of upholding their commitments to reduce greenhouse-gas emissions.
Today, many policy proposals are immediately identified as either “left-wing” or “right-wing," leaving little room for discussion. But there is a way to bypass such divisiveness: trusting cost-benefit analysis to identify the policies and investments that would have the biggest positive impact on society.
Today's most important political struggle is not between globalists and anti-globalists, but rather between two models of integration: one is multilateral and internationalist; the other is bilateral and imperialist. Throughout the modern age, the world has seesawed between them.
While the EU tries to weather a populist, nationalist storm that threatens its core institutions, some of its most important strategic allies have injected more uncertainty into the current political climate. Chief among them is Turkey, which has now taken an alarming turn away from democratic norms.
Populism means a politics of the people, juxtaposed against a politics of the elites. But, at least in the US, President Donald Trump’s ideology – which has little to do with traditional Republican conservatism – frames the axis of division not as the many versus the few, but as nationalists versus globalists.
A new infrared-light WiFi network can provide more than 40 gigabits per second (Gbps) for each user* — about 100 times faster than current WiFi systems — say researchers at Eindhoven University of Technology (TU/e) in the Netherlands.
The TU/e WiFi design was inspired by experimental systems using ceiling LED lights (such as Oregon State University’s experimental WiFiFO, or WiFi Free space Optic, system), which can increase the total per-user speed of WiFi systems and extend the range to multiple rooms, while avoiding interference from neighboring WiFi systems. (However, WiFiFo is limited to 100 Mbps.)
Instead of visible light, the TU/e system uses invisible near-infrared light.** Supplied by a fiber optic cable, a few central “light antennas” (mounted on the ceiling, for instance) each use a pair of ”passive diffraction gratings” that radiate light rays of different wavelengths at different angles.
That allows for directing the light beams to specific users. The network tracks the precise location of every wireless device, using a radio signal transmitted in the return direction.***
The TU/e system uses infrared light with a wavelength of 1500 nanometers (a frequency of 200 terahertz, or 40,000 times higher than 5GHz), allowing for significantly increased capacity. The system has so far used the light rays only for downloading; uploads are still done using WiFi radio signals, since much less capacity is usually needed for uploading.
The researchers expect it will take five years or more for the new technology to be commercially available. The first devices to be connected will likely be high-data devices like video monitors, laptops, and tablets.
* That speed is 67 times higher than the current 802.11n WiFi system’s max theoretical speed of 600Mbps capacity — which has to be shared between users, so the ratio is actually about 100 times, according to TU/e researchers. That speed is also 16 times higher than the 2.5 Gbps performance with the best (802.11ac) Wi-Fi system — which also has to be shared (so actually lower) — and in addition, uses the 5GHz wireless band, which has limited range. “The theoretical max speed of 802.11ac is eight 160MHz 256-QAM channels, each of which are capable of 866.7Mbps, for a total of 6,933Mbps, or just shy of 7Gbps,” notes Extreme Tech. “In the real world, thanks to channel contention, you probably won’t get more than two or three 160MHz channels, so the max speed comes down to somewhere between 1.7Gbps and 2.5Gbps. Compare this with 802.11n’s max theoretical speed, which is 600Mbps.”
** The TU/e system was designed by Joanne Oh as a doctoral thesis and part of the wider BROWSE project headed up by professor of broadband communication technology Ton Koonen, with funding from the European Research Council, under the auspices of the noted TU/e Institute for Photonic Integration.
*** According to TU/e researchers, a few other groups are investigating network concepts in which infrared-light rays are directed using movable mirrors. The disadvantage here is that this requires active control of the mirrors and therefore energy, and each mirror is only capable of handling one ray of light at a time. The grating used the and Oh can cope with many rays of light and, therefore, devices at the same time.
Stanford bioengineers have developed liquid-handling robots to allow students to modify and create their own robotic systems that can transfer precise amounts of fluids between flasks, test tubes, and experimental dishes.
The bioengineers combined a Lego Mindstorms robotics kit with a cheap and easy-to-find plastic syringe to create robots that approach the performance of the far more costly automation systems found at universities and biotech labs.
Step-by-step DIY plans
The idea is to enable students to learn the basics of robotics and the wet sciences in an integrated way. Students learn STEM skills like mechanical engineering, computer programming, and collaboration while gaining a deeper appreciation of the value of robots in life-sciences experiments.
“We really want kids to learn by doing,” said Ingmar Riedel-Kruse, assistant professor of bioengineering and a member of Stanford Bio-X, who led the team. “We show that with a few relatively inexpensive parts, a little training and some imagination, students can create their own liquid-handling robots and then run experiments on it — so they learn about engineering, coding, and the wet sciences at the same time.”
In an open-access paper in the journal PLoS Biology and on Riedel-Kruse’s lab website, the team offers step-by-step building plans and several fundamental experiments targeted to elementary, middle and high school students. They also offer experiments that students can conduct using common household consumables like food coloring, yeast or sugar.
In one experiment, colored liquids with distinct salt concentrations are layered atop one another to teach about liquid density. Other tests measure whether liquids are acids like vinegar or bases like baking soda, or which sugar concentration is best for yeast.
Funding was provided by grants from the National Science Foundation (Cyberlearning and National Robotics Initiative).
Stanford University School of Engineering | SFENG Robots Riedel Kruse v4
Abstract of Liquid-handling Lego robots and experiments for STEM education and research
Liquid-handling robots have many applications for biotechnology and the life sciences, with increasing impact on everyday life. While playful robotics such as Lego Mindstorms significantly support education initiatives in mechatronics and programming, equivalent connections to the life sciences do not currently exist. To close this gap, we developed Lego-based pipetting robots that reliably handle liquid volumes from 1 ml down to the sub-μl range and that operate on standard laboratory plasticware, such as cuvettes and multiwell plates. These robots can support a range of science and chemistry experiments for education and even research. Using standard, low-cost household consumables, programming pipetting routines, and modifying robot designs, we enabled a rich activity space. We successfully tested these activities in afterschool settings with elementary, middle, and high school students. The simplest robot can be directly built from the widely used Lego Education EV3 core set alone, and this publication includes building and experiment instructions to set the stage for dissemination and further development in education and research.
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