Monthly Archives: March 2019
Scientists at Aston University (UK) have discovered a technique similar to medieval stained glass-making that can completely eradicate the deadliest hospital infections within hours.
Using a so-called bioactive phosphate glass containing small amounts of the metallic element cobalt, the researchers were able to achieve a “complete kill” of the deadly bacterial infections E.coli and Candida albicans (a fungal infection associated with surgery), as well as a near-complete kill of Staphylococcus aureus (the drug-resistant form of which is MRSA).
Lead researcher, Dr Richard Martin of Aston University in Birmingham, said the findings had significant implications, offering the possibility of cheap, antimicrobial implants and coatings to combat the most common sources of infections associated with medical care. Avoiding the need for antibiotics, it is also thought the bioactive glass could be effective against drug-resistant ‘superbugs’, helping to tackle the growing problem of antimicrobial resistance (AMR).
According to the European Centre for Disease Prevention and Control (ECDC), over four million people in Europe get a healthcare-associated infection (HAI) every year, and around 37,000 die as a direct result of the infection. In its most recent survey of hospital patients, Public Health England found that 6.4% had a healthcare-associated infection.
In the study, published in the journal ACS Biomaterials, the researchers used a centuries-old technique to make glass laced with trace amounts of cobalt in a furnace heated to over 1,000°C, before rapid cooling to prevent crystallisation. These were then ground down into a fine powder and put into contact with bacteria in petri dishes. The glasses contained varying concentrations of cobalt, providing a controlled release of antimicrobial ions as they dissolved. At the highest concentration, the glass completely eradicated E.coli within just six hours, with a “complete kill” also observed for C.albicans within 24 hours. S.aureus levels were reduced by 99% after 24 hours.
A team of engineers at the UC Berkeley and the Keck Graduate Institute (KGI) of The Claremont Colleges combined CRISPR with electronic transistors made from graphene to create a new hand-held device that can detect specific genetic mutations in a matter of minutes.
The device, dubbed CRISPR-Chip, could be used to rapidly diagnose genetic diseases or to evaluate the accuracy of gene-editing techniques. The team used the device to identify genetic mutations in DNA samples from Duchenne muscular dystrophy patients.
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“We have developed the first transistor that uses CRISPR to search your genome for potential mutations,” said Kiana Aran, an assistant professor at KGI who conceived of the technology while a postdoctoral scholar in UC Berkeley bioengineering professor Irina Conboy’s lab. “You just put your purified DNA sample on the chip, allow CRISPR to do the search and the graphene transistor reports the result of this search in minutes.”
Aran, who developed this technology and brought it to fruition at KGI, is the senior author of a paper describing the device that appears online March 25 in the journal Nature Biomedical Engineering.
Doctors and geneticists can now sequence DNA to pinpoint genetic mutations underlying a host of traits and conditions, and companies like 23andMe and AncestryDNA even make these tests available to curious consumers.
Materials scientists at Duke University have theorized a new “oil-and-vinegar” approach to engineering self-assembling materials of unusual architectures made out of spherical nanoparticles. The resulting structures could prove useful to applications in optics, plasmonics, electronics and multi-stage chemical catalysis. Left to their own tendencies, a system of suspended spherical nanoparticles designed to clump together will try to maximize their points of contact by packing themselves as tightly as possible. This results in the formation of either random clusters or a three-dimensional, crystalline structure.
But materials scientists often want to build more open structures of lower dimensions, such as strings or sheets, to take advantage of certain phenomena that can occur in the spaces between different types of particles. In the new study, Gaurav Arya, associate professor of mechanical engineering and materials science at Duke, proposes a method that takes advantage of the layers formed by liquids that, like a bottle of vinaigrette left on the shelf for too long, refuse to mix together.
When spherical nanoparticles are placed into such a system, they tend to form a single layer at the interface of the opposing liquids. But they don’t have to stay there. By attaching “oil” or “vinegar” molecules to the particles’ surfaces, researchers can make them float more on one side of the dividing line than the other.
“The particles want to maximize their number of contacts and form bulk-like structures, but at the same time, the interface of the different liquids is trying to force them into two layers,” said Arya. “So you have a competition of forces, and you can use that to form different kinds of unique and interesting structures.”
Arya’s idea is to precisely control the amount that each spherical nanoparticle is repelled by one liquid or the other. And according to his calculations, by altering this property along with others such as the nanoparticles’ composition and size, materials scientists can make all sorts of interesting shapes, from spindly molecule-like structures to zig-zag structures where only two nanoparticles touch at a time. One could even imagine several different layers working together to arrange a system of nanoparticles.
In the proof-of-concept paper, the nanoparticles could be made out of anything. Gold or semiconductors could be useful for plasmonic and electrical devices, while other metallic elements could catalyze various chemical reactions. The opposing substrates that form the interface, meanwhile, are modeled after various types of polymers that could also be used in such applications.
The novel approach appeared online on March 25 in the journal ACS Nano.
A University of Maryland-led team of researchers has created a heat-to-electricity device that runs on ions and which could someday harness the body’s heat to provide energy.
Led by UMD researchers Liangbing Hu, Robert Briber and Tian Li of the department of materials science, and Siddhartha Das of mechanical engineering, the team transformed a piece of wood into a flexible membrane that generates energy from the same type of electric current (ions) that the human body runs on. This energy is generated using charged channel walls and other unique properties of the wood’s natural nanostructures. With this new wood-based technology, they can use a small temperature differential to efficiently generate ionic voltage, as demonstrated in a paper published in the journal Nature Materials.
If you’ve ever been outside during a lightning storm, you’ve seen that generating charge between two very different temperatures is easy. But for small temperature differences, it is more difficult. However, the team says they have succesfully tackled this challenge. Hu said they now have “demonstrated their proof-of-concept device, to harvest low-grade heat using nanoionic behavior of processed wood nanostructures”.
Trees grow channels that move water between the roots and the leaves. These are made up of fractally-smaller channels, and at the level of a single cell, channels just nanometers or less across. The team has harnessed these channels to regulate ions.
The researchers used basswood, which is a fast-growing tree with low environmental impact. They treated the wood and removed two components – lignin, that makes the wood brown and adds strength, and hemicellulose, which winds around the layers of cells binding them together. This gives the remaining cellulose its signature flexibility. This process also converts the structure of the cellulose from type I to type II which is a key to enhancing ion conductivity.
A membrane, made of a thin slice of wood, was bordered by platinum electrodes, with sodium-based electrolyte infiltrated into the cellulose. The regulate the ion flow inside the tiny channels and generate electrical signal. “The charged channel walls can establish an electrical field that appears on the nanofibers and thus help effectively regulate ion movement under a thermal gradient,” said Tian Li, first author of the paper.
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 International’s 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.
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.
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 different “software.”
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.
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.
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.
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“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.
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.”