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How To Produce Entire Homes With A 3D Printer

If you’re looking for a 3D printer that can fit comfortably on the side of your desk and bust out small home-printed objects, then Danish company Cobod Internationals new 3D printer definitely isn’t for you. Roughly the size of a small barn, the BOD2 is the world’s largest 3D printer designed for construction purposes. It is capable of printing entire buildings up to 40 feet wide, 90 feet long and 30 feet tall. In other words, if you’re only looking to print out a DIY fidget spinner, you’re going to want to search elsewhere.

Our second-generation 3D construction printer, BOD2, is special in the way that it has a modular frame which gives the opportunity for our customers to choose the size of printer that fits their specific purpose,” said Asger Dath, communications manager for Cobod, “Furthermore, it is currently the fastest-printing construction printer on the market. With the tangential controlled print head, together with our customizable nozzle system, our customers are able to print different wall surfaces, especially very smooth wall surfaces.”

The printer functions in a very similar way  to a standard FDM (fused filament fabrication) printer. It is fed with concrete, which is then extruded using a motor in the print head. This concrete material is fed into the printer as a dry mix, prior to being mixed by a pump and then traveling through a tube to the print head to be expelled.

We decided to develop the BOD2 after we found a great interest from the construction industry after we 3D printed the first building in Europe,” Dath said. “The many requests we got had all different purposes and therefore the sizes differed a great deal. [This] led to the idea of developing a modular construction printer that could meet the needs of all the requested sizes, instead of developing a printer in one or two sizes.”

The BOD2 printer was recently purchased by the construction company Elite for Construction & Development Co., with the express purpose of creating 3D printed private homes in Saudi Arabia. This is going to be a big job. In all, Saudi Arabia aims to build 1.5 million private houses over the next decade. While not all of those will necessarily be 3D printed, a tool such as this could certainly help save on both time and money.


How To Levitate Objects With Light

Researchers at Caltech have designed a way to levitate and propel objects using only light, by creating specific nanoscale patterning on the objects’ surfaces. Though still theoretical, the work is a step toward developing a spacecraft that could reach the nearest planet outside of our solar system in 20 years, powered and accelerated only by light. The research was done in the laboratory of Harry Atwater, Howard Hughes Professor of Applied Physics and Materials Science in Caltech’s Division of Engineering and Applied Science.

Decades ago, the development of so-called optical tweezers enabled scientists to move and manipulate tiny objects, like nanoparticles, using the radiative pressure from a sharply focused beam of laser light. This work formed the basis for the 2018 Nobel Prize in Physics. However, optical tweezers are only able to manipulate very small objects and only at very short distances. Ognjen Ilic, postdoctoral scholar and the study’s first author, gives an analogy: “One can levitate a ping pong ball using a steady stream of air from a hair dryer. But it wouldn’t work if the ping pong ball were too big, or if it were too far away from the hair dryer, and so on.”

With this new research, objects of many different shapes and sizes—from micrometers to meters—could be manipulated with a light beam. The key is to create specific nanoscale patterns on an object’s surface. This patterning interacts with light in such a way that the object can right itself when perturbed, creating a restoring torque to keep it in the light beam. Thus, rather than requiring highly focused laser beams, the objects’ patterning is designed to “encode” their own stability. The light source can also be millions of miles away.

“We have come up with a method that could levitate macroscopic objects,” says Atwater, who is also the director of the Joint Center for Artificial Photosynthesis. “There is an audaciously interesting application to use this technique as a means for propulsion of a new generation of spacecraft. We’re a long way from actually doing that, but we are in the process of testing out the principles.”

In theory, this spacecraft could be patterned with nanoscale structures and accelerated by an Earth-based laser light. Without needing to carry fuel, the spacecraft could reach very high, even relativistic speeds and possibly travel to other stars.

Atwater also envisions that the technology could be used here on Earth to enable rapid manufacturing of ever-smaller objects, like circuit boards.

A paper describing the research appears online in the journal Nature Photonics.


Molecular Nanocomputers

Computer scientists at Caltech have designed DNA molecules that can carry out reprogrammable computations, for the first time creating so-called algorithmic self-assembly in which the same “hardware” can be configured to run differentsoftware.”

A team headed by Caltech‘s Erik Winfree (PhD ’98), professor of computer science, computation and neural systems, and bioengineering, showed how the DNA computations could execute six-bit algorithms that perform simple tasks. The system is analogous to a computer, but instead of using transistors and diodes, it uses molecules to represent a six-bit binary number (for example, 011001) as input, during computation, and as output. One such algorithm determines whether the number of 1-bits in the input is odd or even, (the example above would be odd, since it has three 1-bits); while another determines whether the input is a palindrome; and yet another generates random numbers.

Think of them as nano apps,” says Damien Woods, professor of computer science at Maynooth University near Dublin, Ireland, and one of two lead authors of the study. “The ability to run any type of software program without having to change the hardware is what allowed computers to become so useful. We are implementing that idea in molecules, essentially embedding an algorithm within chemistry to control chemical processes.”

The system works by self-assembly: small, specially designed DNA strands stick together to build a logic circuit while simultaneously executing the circuit algorithm. Starting with the original six bits that represent the input, the system adds row after row of molecules—progressively running the algorithm. Modern digital electronic computers use electricity flowing through circuits to manipulate information; here, the rows of DNA strands sticking together perform the computation. The end result is a test tube filled with billions of completed algorithms, each one resembling a knitted scarf of DNA, representing a readout of the computation. The pattern on each “scarf” gives you the solution to the algorithm that you were running. The system can be reprogrammed to run a different algorithm by simply selecting a different subset of strands from the roughly 700 that constitute the system.

We were surprised by the versatility of programs we were able to design, despite being limited to six-bit inputs,” says David Doty, fellow lead author and assistant professor of computer science at the University of California, Davis. “When we began experiments, we had only designed three programs. But once we started using the system, we realized just how much potential it has. It was the same excitement we felt the first time we programmed a computer, and we became intensely curious about what else these strands could do. By the end, we had designed and run a total of 21 circuits.”

The findings have been reported in the journal Nature.


Cost-Effective Method For Hydrogen Fuel Production

Nanoparticles composed of nickel and iron have been found to be more effective and efficient than other, more costly materials when used as catalysts in the production of hydrogen fuel through water electrolysis. The discovery was made by University of Arkansas researchers Jingyi Chen, associate professor of physical chemistry, and Lauren Greenlee, assistant professor of chemical engineering, as well as colleagues from Brookhaven National Lab and Argonne National Lab. The researchers demonstrated that using nanocatalysts composed of nickel and iron increases the efficiency of water electrolysis, the process of breaking water atoms apart to produce hydrogen and oxygen and combining them with electrons to create hydrogen gas.

Chen and her colleagues discovered that when nanoparticles composed of an iron and nickel shell around a nickel core are applied to the process, they interact with the hydrogen and oxygen atoms to weaken the bonds, increasing the efficiency of the reaction by allowing the generation of oxygen more easily. Nickel and iron are also less expensive than other catalysts, which are made from scarce materials.

This marks a step toward making water electrolysis a more practical and affordable method for producing hydrogen fuel. Current methods of water electrolysis are too energy-intensive to be effective.

Chen, Greenlee and their colleagues recently published their results in the journal Nanoscale.


Rotating Black Holes Might Serve As Portals For Hyperspace Travel

Black holes skirt the line between science fiction and science fact. On the one hand, scientists have seen real black holes in action, consuming unsuspecting stars that pass too close. But where reality ends and fiction takes over is at the edge of a black hole — a place called the event horizon, where no spacecraft has ever gone.

So, whatever happens beyond that boundary, inside of a black hole, is anyone’s guess. Scientists agree that if you travel far enough into a black hole, gravity will eventually become so strong that it kills anything in its path. But sci-fi films are more optimistic, depicting black holes as portals through space and time or gateways to other dimensions. And it turns out, some scientists now think the sci-fi buffs may be onto something. Black holes might be suitable for hyperspace travel, after all; it just takes the right kind of black hole. At the center of every black hole is a point of infinite density, called a singularity. It’s what gives black holes their strong gravitational pull. And for decades, scientists thought singularities were all the same, so anything that passed the event horizon would be destroyed the same way: by being stretched and pulled like an infinitely long piece of spaghetti.

But that all changed in the early 1990s when different research teams in Canada and the US discovered a second singularity called a “mass inflation singularity.” It still has a strong gravitational pull, but it would only stretch you by a finite amount, and potentially NOT kill you in the process, meaning, you might survive the trip through a black hole. More specifically, through a large, rotating black hole, which is where these types of singularities exist.

Now, astronomers obviously can’t travel through a black hole yet to test this theory. In fact, the best place to test this is at the supermassive black hole in the center of our home galaxy, the Milky Way, which is 27,000 light years away. Not conveniently close to the least.

Therefore, scientists instead run computer simulations to see what would happen if we did manage to reach an isolated, rotating black hole, and now, for the first time, a team of scientists at UMass Dartmouth and Georgia Gwinnett College has done exactly that.


You would feel a slight increase in temperature, but it would not be a dramatic increase. It’s just that you don’t have enough time to respond to the very strong forces. It would just go through you too quickly,” said Lior Burko from Georgia Gwinnett College.  He added that passing through a weak singularity is like quickly running your finger through a candle flame that’s 1,000 degrees Celsius. If you hold your finger in the flame long enough, you’ll get burned, but pass your finger through quickly, and you’ll barely feel a thing. Similarly, if you pass through a weak singularity with the right speed and momentum, and at the right time, you may not feel much at all.

As for what happens once you get through to the other side, no one really knows, but Burko has his own ideas. He says one possibility is that we’d arrive at some other remote part of our galaxy, potentially light years away from any planets or stars, but a second, and perhaps more intriguing, possibility is that we’d arrive in a different galaxy altogether. That’s if you even make it that far. Scientists say more research is needed before we’re anywhere close to successfully traveling through a black hole. But when we are ready, one of the safest passageways might be the supermassive black hole at the center of our galaxy called Sagittarius A*, and it might just be our ticket out of the Milky Way.


Cancer’s ‘Internal Wiring’ Predicts Relapse Risk

The “internal wiring” of breast cancer can predict which women are more likely to survive or relapse, say researchers. The study shows that breast cancer is 11 separate diseases that each has a different risk of coming back. The hope is that the findings, in the journal Nature, could identify people needing closer monitoring and reassure others at low risk of recurrence.

Cancer Research UK said that the work was “incredibly encouraging” but was not yet ready for widespread use. The scientists, at the University of Cambridge and Stanford University, looked in incredible detail at nearly 2,000 women’s breast cancers. They went far beyond considering all breast cancers as a single disease and beyond modern medicine’s way of classifying the tumours.

Doctors currently classify breast cancers based on whether they respond to the hormone oestrogen or targeted therapies like Herceptin. The research team analysed the genetic mutations inside the tumour to create a new way of classifying them.

By following women for 20 years, they are now able to show which types of breast cancer are more likely to come back.  “This is really biology-driven, it’s the molecular wiring of your tumour, said Prof Carlos Caldas. Once and for all we need to stop talking about breast cancer as one disease, it’s a constellation of 11 diseases. “This is a very significant step to more precision-type medicine.”


How To Reverse Vascular Disease In Kidney Failure

By loading a chelation drug into a nano-sized homing device, researchers at Clemson University have reversed in an animal model the deadliest effects of chronic kidney disease, which kills more people in the United States each year than breast or prostate cancer. When kidneys stop working properly, calcium builds up in artery tissue, leading to heart disease. Although nearly half a million Americans receive kidney dialysis, heart disease is the leading cause of death for people with chronic kidney disease.

Human kidney cross section on scientific background

The findings are very exciting scientifically, but also for the thousands of patients who could potentially benefit from this technology one day,” said Naren Vyavahare, professor of bioengineering at Clemson and the principal investigator of the research.

Chelation, a method of removing metals such as iron and lead from the body, has been used experimentally for some people with heart disease. The therapy is not approved by the Food and Drug Administration, but the National Institutes of Health has sponsored two large-scale, multi-center studies using ethylene diamine tetra-acetic acid, or EDTA, as chelation therapy for people with heart disease.

In clinical studies, EDTA is included in an infusion that circulates through the body; it’s systemic and non-specific. This method of chelation has shown good results in improving heart function, especially in diabetic patients, Vyavahare said. But EDTA infusion therapy is arduous (it requires 40 infusions over a period of a year), and it can cause side effects, including a depletion of calcium from the blood and from bone.

Now, in a paper published in Scientific Reports, a Nature publication, Vyavahare’s team describes how they developed an animal model that mimics a human’s chronic kidney disease. Animals were treated either with EDTA infusions, like in the NIH human trials, or with EDTA enclosed in a nanoparticle coupled with an antibody that seeks out damaged elastin. In animals that received the targeted therapy, calcium buildup was destroyed, without causing side effects, better than with EDTA infusions alone. Moreover, the calcification did not come back up to four weeks after the last injection, even though other signs of chronic kidney disease were present.


Nanorobots Probe Into Cells

U of T Engineering researchers have built a set of magnetic tweezers’ that can position a nano-scale bead inside a human cell in three dimensions with unprecedented precision. The nano-bot has already been used to study the properties of cancer cells, and could point the way toward enhanced diagnosis and treatment.

Professor Yu Sun (MIE, IBBME, ECE) and his team have been building robots that can manipulate individual cells for two decades. Their creations have the ability to manipulate and measure single cells — useful in procedures such as in vitro fertilization and personalized medicine. Their latest study, published today in Science Robotics, takes the technology one step further.

The magnetic bead introduced into the cell and controlled to be navigated onto the nuclear envelope.

So far, our robot has been exploring outside a building, touching the brick wall, and trying to figure out what’s going on inside,” says Sun. “We wanted to deploy a robot in the building and probe all the rooms and structures.” The team has created robotic systems that can manipulate sub-cellular structures inside electron microscopes, but that requires freeze-drying the cells and cutting them into tiny slices. To probe live cells, other teams have used techniques such as lasers or acoustics.

Optical tweezers — using lasers to probe cells — is a popular approach,” says Xian Wang (MIE), the PhD candidate who conducted the research. The technology was honoured with 2018 Nobel Prize in Physics, but Wang says the force that it can generate is not large enough for mechanical manipulation and measurement he wanted to do. “You can try to increase the power to generate higher force, but you run the risk of damaging the sub-cellular components you’re trying to measure,” says Wang.

The system Wang designed uses six magnetic coils placed in different planes around a microscope coverslip seeded with live cancer cells. A magnetic iron bead about 700 nanometres in diameter — about 100 times smaller than the thickness of a human hair — is placed on the coverslip, where the cancer cells easily take it up inside their membranes. Once the bead is inside, Wang controls its position using real-time feedback from confocal microscopy imaging. He uses a computer-controlled algorithm to vary the electrical current through each of the coils, shaping the magnetic field in three dimensions and coaxing the bead into any desired position within the cell.

We can control the position to within a couple of hundred nanometers down the Brownian motion limit,” says Wang. “We can exert forces an order of magnitude higher than would be possible with lasers.”

In collaboration with Dr. Helen McNeil and Yonit Tsatskis at Mount Sinai Hospital and Dr. Sevan Hopyan at The Hospital for Sick Children (SickKids), the team used their robotic system to study early-stage and later-stage bladder cancer cells. Previous studies on cell nuclei required their extraction of from cells. Wang and Sun measured cell nuclei in intact cells without the need to break apart the cell membrane or cytoskeleton. They were able to show that the nucleus is not equally stiff in all directions. “It’s a bit like a football in shape — mechanically, it’s stiffer along one axis than the other,” says Sun. “We wouldn’t have known that without this new technique.”

They were also able to measure exactly how much stiffer the nucleus got when prodded repeatedly, and determine which cell protein or proteins may play a role in controlling this response. This knowledge could point the way toward new methods of diagnosing cancer. “We know that in the later-stage cells, the stiffening response is not as strong,” says Wang. “In situations where early-stage cancer cells and later-stage cells don’t look very different morphologically, this provides another way of telling them apart.”

According to Sun, the research could go even further. “You could imagine bringing in whole swarms of these nano-bots, and using them to either starve a tumour by blocking the blood vessels into the tumor, or destroy it directly via mechanical ablation,” says Sun. “This would offer a way to treat cancers that are resistant to chemotherapy, radiotherapy and immunotherapy.”


Conflicting Realities

Physicists have long suspected that quantum mechanics allows two observers to experience different, conflicting realities. Now they’ve performed the first experiment that proves it. Back in 1961, the Nobel Prize–winning physicist Eugene Wigner outlined a thought experiment that demonstrated one of the lesser-known paradoxes of quantum mechanics. The experiment shows how the strange nature of the universe allows two observers—say, Wigner and Wigner’s friend—to experience different realities.

Since then, physicists have used the “Wigner’s Friend” thought experiment to explore the nature of measurement and to argue over whether objective facts can exist. That’s important because scientists carry out experiments to establish objective facts. But if they experience different realities, the argument goes, how can they agree on what these facts might be?
That’s provided some entertaining fodder for after-dinner conversation, but Wigner’s thought experiment has never been more than that—just a thought experiment. Last year, however, physicists noticed that recent advances in quantum technologies have made it possible to reproduce the Wigner’s Friend test in a real experiment. In other words, it ought to be possible to create different realities and compare them in the lab to find out whether they can be reconciled.

And today, Massimiliano Proietti at Heriot-Watt University in Edinburgh and a few colleagues say they have performed this experiment for the first time: they have created different realities and compared them. Their conclusion is that Wigner was correct—these realities can be made irreconcilable so that it is impossible to agree on objective facts about an experiment.Wigner’s original thought experiment is straightforward in principle. It begins with a single polarized photon that, when measured, can have either a horizontal polarization or a vertical polarization. But before the measurement, according to the laws of quantum mechanics, the photon exists in both polarization states at the same time—a so-called superposition.

Wigner imagined a friend in a different lab measuring the state of this photon and storing the result, while Wigner observed from afar. Wigner has no information about his friend’s measurement and so is forced to assume that the photon and the measurement of it are in a superposition of all possible outcomes of the experiment.

But this is in stark contrast to the point of view of the friend, who has indeed measured the photon’s polarization and recorded it. The friend can even call Wigner and say the measurement has been done (provided the outcome is not revealed). So the two realities are at odds with each other. “This calls into question the objective status of the facts established by the two observers,” say Proietti and co. That’s the theory, but last year Caslav Brukner, at the University of Vienna in Austria, came up with a way to re-create the Wigner’s Friend experiment in the lab by means of techniques involving the entanglement of many particles at the same time.

The breakthrough that Proietti and co have made is to carry this out. “In a state-of-the-art 6-photon experiment, we realize this extended Wigner’s friend scenario,” they say. They use these six entangled photons to create two alternate realities—one representing Wigner and one representing Wigner’s friend. Wigner’s friend measures the polarization of a photon and stores the result. Wigner then performs an interference measurement to determine if the measurement and the photon are in a superposition.

The experiment produces an unambiguous result. It turns out that both realities can coexist even though they produce irreconcilable outcomes, just as Wigner predicted.  That raises some fascinating questions that are forcing physicists to reconsider the nature of reality.


3D printing becoming a surgical game changer

Imagine 1,000 puzzle pieces without any picture of what it’s ultimately supposed to look like. With few, if any, reference points, the challenge of fitting them together would be daunting. That’s what surgeons often confront when a patient suffering from a traumatic injury or condition has a portion of their body that is dramatically damaged or changed. The “puzzle” can be exponentially harder when the injuries involve a person’s face or skull – areas of the human anatomy that are complex, difficult to surgically navigate, and often require both functional and near-perfect cosmetic repair.

Now, thanks to high-tech equipment that is sometimes not much bigger than a home printer, UC Davis Health physicians are enhancing their capabilities and mapping out surgeries in ways that benefit patients and surgical outcomes.


3D printing, which for us means manufacturing that’s accurate, affordable and on-site, can be a game changer in health care,” said David Lubarsky, vice chancellor for Human Health Sciences and CEO of UC Davis Health, who is very encouraged by the university’s newest technology initiatives and promising results.

The new device is a specialized but fairly affordable printer that produces three-dimensional models of an individual’s skull or body part. The 3D models enable a surgeon to visualize, practice and then perform the reconstructive surgery while saving time and increasing precision.

Facial reconstructive surgery involves intricate anatomy within an extremely narrow operative field in which to maneuver our instruments,” said E. Bradley Strong, a professor of otolaryngology who specializes in facial reconstructive surgery. “Being able to print out a high-resolution 3D model of the injury, allows us to do detailed preoperative planning and preparation that is more efficient and accurate. We can also use these patient specific models in the operating room to improve the accuracy of implant placement.”

The 3D printer used by Strong and his colleagues for the past year is about the size of a mini-refrigerator and costs approximately $4,000. It uses the imaging data from a patient’s computed tomography (CT) scans to provide the modeling output information. Like an inkjet printer, the 3D version spits out layer upon layer of material over a period of hours, sometimes taking nearly a day to complete, depending on the complexity of the model. The finished replica can save time during surgery, which means less time on the operating table for a patient and potentially a better outcome.

By creating a 3D model prior to surgery, Strong is able to bend and customize generic surgical plates into patient-specific shapes that fit perfectly for each individual patient.