How to Produce Drinkable Water from Sea Water

University of California, Berkeley, chemists have discovered a way to simplify the removal of toxic metals, like mercury and boron, during desalination to produce clean water, while at the same time potentially capturing valuable metals, such as gold.

Desalination — the removal of salt — is only one step in the process of producing drinkable water, or water for agriculture or industry, from ocean or waste water. Either before or after the removal of salt, the water often has to be treated to remove boron, which is toxic to plants, and heavy metals like arsenic and mercury, which are toxic to humans. Often, the process leaves behind a toxic brine that can be difficult to dispose of.

The new technique, which can easily be added to current membrane-based electrodialysis desalination processes, removes nearly 100% of these toxic metals, producing a pure brine along with pure water and isolating the valuable metals for later use or disposal.

A flexible polymer membrane incorporating nanoparticles of PAF selectively absorbs nearly 100% of metals such mercury, copper or iron during desalination, more efficiently producing clean, safe water

Desalination or water treatment plants typically require a long series of high-cost, pre- and post-treatment systems that all the water has to go through, one by one,” said Adam Uliana, a UC Berkeley graduate student who is first author of a paper describing the technology. “But here, we have the ability to do several of these steps all in one, which is a more efficient process. Basically, you could implement it in existing setups.”

The UC Berkeley chemists synthesized flexible polymer membranes, like those currently used in membrane separation processes, but embedded nanoparticles that can be tuned to absorb specific metal ionsgold or uranium ions, for example. The membrane can incorporate a single type of tuned nanoparticle, if the metal is to be recovered, or several different types, each tuned to absorb a different metal or ionic compound, if multiple contaminants need to be removed in one step.

The polymer membrane laced with nanoparticles is very stable in water and at high heat, which is not true of many other types of absorbers, including most metal-organic frameworks (MOFs), when embedded in membranes.

Source: https://news.berkeley.edu/

How To Uncloak Cancer Cells And Reveal Them To The Immune System

Scientists at Johns Hopkins report they have designed and successfully tested an experimental, super small package able to deliver molecular signals that tag implanted human cancer cells in mice and make them visible for destruction by the animals’ immune systems. The new method was developed, say the researchers, to deliver an immune system “uncloaking” device directly to cancer cells.

Conventional immune therapies generally focus on manipulating patients’ immune system cells to boost their cancer-killing properties or injecting drugs that do the same but often have toxic side effectsA hallmark of cancer biology is a tumor cell’s ability to essentially hide from the immune system cells whose job is to identify and destroy cancer cells. Current cellular immunotherapies, notably CAR-T, require scientists to chemically alter and enhance a patient’s own harvested immune system T-cells — an expensive and time-consuming process, say the researchers. Other weapons in the arsenal of immunotherapies are drugs, including so-called checkpoint inhibitors, which have broad effects and often lead to unwanted immune-system-associated side effects, including damage to normal tissue.

By contrast, the Johns Hopkins team sought an immune system therapy that can work like a drug but that also individually engineers a tumor and its surrounding environment to draw the immune system cells to it, says Jordan Green, Ph.D, professor of biomedical engineering at the Johns Hopkins University School of Medicine.

A microscopic image of the nanoparticles used in the study. The black scale bar is 100 nm in size
 And our process happens entirely within the body,” Green says, “requiring no external manipulation of a patient’s cells.

To develop the new system, Green and his team, including Stephany Tzeng, Ph.D., a research associate in the Department of Biomedical Engineering at Johns Hopkins, took advantage of a cancer cell’s tendency to internalize molecules from its surroundings. “Cancer cells may be easier to directly genetically manipulate because their DNA has gone haywire, they divide rapidly, and they don’t have the typical checks and balances of normal cells,” says Green.

The team created a polymer-based nanoparticle — a tiny case that slips inside cells. They guided the nanoparticles to cancer cells by injecting them directly into the animals’ tumors. “The nanoparticle method we developed is widely applicable to many solid tumors despite their variability on an individual and tumor type level,” says Green, also a member of the Johns Hopkins Kimmel Cancer Center. Once inside the cell, the water-soluble nanoparticle slowly degrades over a day. It contains a ring of DNA, called a plasmid, that does not integrate into the genome and is eventually degraded as the cancer cell divides, but it stays active long enough to alter protein production in the cell.

The additional genomic material from the plasmid makes the tumor cells produce surface proteins called 4-1BBL, which work like red flags to say, “I’m a cancer cell, activate defenses.” The plasmid also forces the cancer cells to secrete chemicals called interleukins into the space around the cells. The 4-1BBL tags and interleukins are like magnets to immune system cells, and they seek to kill the foreign-looking cancer cells.

Results of the proof-of-concept experiments were published online in the Proceedings of the National Academy of Sciences.

Source: https://www.hopkinsmedicine.org/

3D-printed Guns Are Back

A new network of 3D-printed gun advocates is growing in America – and this time things are different. Unlike previous attempts to popularise 3D-printed guns, this operation is entirely decentralised. There’s no headquarters, no trademarks, and no real leader. The people behind it reckon that this means they can’t be stopped by governments.


3D-polymer-Glock

If they [the government] were to come after me, they’d first have to find my identity,” says Ivan the Troll, a member of the group. “I’m one of many, many like-minded individuals who’re doing this sort of work.”

Flexible Generators Turn Movement Into Energy

Wearable devices that harvest energy from movement are not a new idea, but a material created at Rice University may make them more practical. The Rice lab of chemist James Tour has adapted laser-induced graphene (LIG) into small, metal-free devices that generate electricity. Like rubbing a balloon on hair, putting LIG composites in contact with other surfaces produces static electricity that can be used to power devices. For that, thank the triboelectric effect, by which materials gather a charge through contact. When they are put together and then pulled apart, surface charges build up that can be m.

In experiments, the researchers connected a folded strip of LIG to a string of light-emitting diodes and found that tapping the strip produced enough energy to make them flash. A larger piece of LIG embedded within a flip-flop let a wearer generate energy with every step, as the graphene composite’s repeated contact with skin produced a current to charge a small capacitor.

An electron microscope image shows a cross-section of a laser-induced graphene and polyimide composite created at Rice University for use as a triboelectric nanogenerator. The devices are able to turn movement into energy that can then be stored for later use

This could be a way to recharge small devices just by using the excess energy of heel strikes during walking, or swinging arm movements against the torso,” Tour said.

LIG is a graphene foam produced when chemicals are heated on the surface of a polymer or other material with a laser, leaving only interconnected flakes of two-dimensional carbon. The lab first made LIG on common polyimide, but extended the technique to plants, food, treated paper and wood.

The project is detailed in the American Chemical Society journal ACS Nano.

Source: http://news.rice.edu/

How To Boost Batteries Conductivity And Improve Safety

Building a better lithium-ion battery involves addressing a myriad of factors simultaneously, from keeping the battery’s cathode electrically and ionically conductive to making sure that the battery stays safe after many cycles.

In a new discovery, scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory have developed a new cathode coating by using an oxidative chemical vapor deposition technique that can help solve these and several other potential issues with lithium-ion batteries all in one stroke.

The coating we’ve discovered really hits five or six birds with one stone.” Khalil Amine, Argonne distinguished fellow and battery scientist. In the research, Amine and his fellow researchers took particles of Argonne’s pioneering nickel-manganese-cobalt (NMC) cathode material and encapsulated them with a sulfur-containing polymer called PEDOT. This polymer provides the cathode a layer of protection from the battery’s electrolyte as the battery charges and discharges.

Unlike conventional coatings, which only protect the exterior surface of the micron-sized cathode particles and leave the interior vulnerable to cracking, the PEDOT coating had the ability to penetrate to the cathode particle’s interior, adding an additional layer of shielding. In addition, although PEDOT prevents the chemical interaction between the battery and the electrolyte, it does allow for the necessary transport of lithium ions and electrons that the battery requires in order to function.

This coating is essentially friendly to all of the processes and chemistry that makes the battery work and unfriendly to all of the potential reactions that would cause the battery to degrade or malfunction,” said Argonne chemist Guiliang Xu, the first author of the research.

Source: https://www.anl.gov/

Pixels A Million Times Smaller

The smallest pixels yet created – a million times smaller than those in smartphones, made by trapping particles of light under tiny rocks of gold – could be used for new types of large-scale flexible displays, big enough to cover entire buildings. The colour pixels, developed by a team of scientists led by the University of Cambridge, are compatible with roll-to-roll fabrication on flexible plastic films, dramatically reducing their production cost.
It has been a long-held dream to mimic the colour-changing skin of octopus or squid, allowing people or objects to disappear into the natural background, but making large-area flexible display screens is still prohibitively expensive because they are constructed from highly precise multiple layers. At the centre of the pixels developed by the Cambridge scientists is a tiny particle of gold a few billionths of a metre across. The grain sits on top of a reflective surface, trapping light in the gap in between. Surrounding each grain is a thin sticky coating which changes chemically when electrically switched, causing the pixel to change colour across the spectrum.

The team of scientists, from different disciplines including physics, chemistry and manufacturing, made the pixels by coating vats of golden grains with an active polymer called polyaniline and then spraying them onto flexible mirror-coated plastic, to dramatically drive down production cost. The pixels are the smallest yet created, a million times smaller than typical smartphone pixels. They can be seen in bright sunlight and because they do not need constant power to keep their set colour, have an energy performance that makes large areas feasible and sustainable. “We started by washing them over aluminized food packets, but then found aerosol spraying is faster,” said co-lead author Hyeon-Ho Jeong from Cambridge’s Cavendish Laboratory.

These are not the normal tools of nanotechnology, but this sort of radical approach is needed to make sustainable technologies feasible,” said Professor Jeremy J Baumberg of the NanoPhotonics Centre at Cambridge’s Cavendish Laboratory, who led the research. “The strange physics of light on the nanoscale allows it to be switched, even if less than a tenth of the film is coated with our active pixels. That’s because the apparent size of each pixel for light is many times larger than their physical area when using these resonant gold architectures.”

The pixels could enable a host of new application possibilities such as building-sized display screens, architecture which can switch off solar heat load, active camouflage clothing and coatings, as well as tiny indicators for coming internet-of-things devices.

The results are reported in the journal Science Advances.

Source: https://www.cam.ac.uk/

Self-Sterilizing Microneedles

Vaccinations are the world’s frontline defence against infectious diseases yet despite decades of interventions, unsafe injection practices continue to expose billions of people to serious infection and disease.

Now, new technology from the University of South Australia is revolutionising safe vaccination practices through antibacterial, silver-loaded dissolvable microneedle patches, which not only sterilise the injection site to inhibit the growth of bacteria, but also physically dissolve after administration.

These first generation microneedles have the potential to transform the safe administration of transdermal vaccinations and drug delivery”, explains Lead researcher, Professor Krasimir Vasilev .

Injections are one of the most common health care procedures used for vaccinations and curative care around the world,” Prof Vasilev adds. “But up to 40 per cent of injections are given with improperly sterilised syringes and needles, placing millions of people at risk of contracting a range of illnesses or diseases. “Our silver-loaded microneedles have inherently potent antibacterial properties which inhibit the growth of pathogenic bacteria and reduce the chance of infection.”

The UniSA study tested the antibacterial efficacy of silver-loaded microneedles against bacteria associated with common skin infections – Golden staph, staphylococcus epidermis, escherichia coli and pseudomonas aeruginosa – and found that the silver-loaded microneedle patches created a 24-hour bacteria-free zone around the patch administration site, a feature unique to the new technology.

The silver-loaded microneedles comprise an array of 15 x 15 needles each 700 micron in length, which pierce only the top layer of the skin without reaching the underlying nerves, making them 100 per cent painless.

The microneedles are made from a safe, biocompatible and highly water-soluble polymer that completely dissolve within one minute of application, leaving behind no sharp waste.

Source: http://www.unisa.edu.au/

How To Make Fuel From Tree Waste

Might tree roots, twigs and branches one day be used to power cars? That’s what a Swedish researcher is hoping after developing a pulp byproduct that – on a modest scale – does just that.

Chemical engineering scientist Christian Hulteberg, from Lund University, has used the black liquor residue from pulp and paper manufacturing to create a polymer called lignin.

After purification and filtration, that is then turned into a gasoline mixture.

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We’re actually using the stuff of the wood that they don’t use when they make paper and pulp… It adds value to low-value components of the tree,” he told Reuters.

In environmental terms, he says that gives it an advantage over other biofuels such as ethanol. “A lot of the controversy with ethanol production has been the use of feedstock that you can actually eat,” he said.

Source: https://www.reuters.com/

How To Charge In Seconds 3D Batteries

The world is a big place, but it’s gotten smaller with the advent of technologies that put people from across the globe in the palm of one’s hand. And as the world has shrunk, it has also demanded that things happen ever faster – including the time it takes to charge an electronic device.

A cross-campus collaboration led by Ulrich Wiesner, Professor of Engineering in the Department of Materials Science at Cornell University, addresses this demand with a novel energy storage device architecture that has the potential for lightning-quick charges.

The group’s idea: Instead of having the batteries’ anode and cathode on either side of a nonconducting separator, intertwine the components in a self-assembling, 3D gyroidal structure, with thousands of nanoscale pores filled with the components necessary for energy storage and delivery.

A rendering of the 3D battery architecture (top; not to scale) with interpenetrating anode (grey, with minus sign), separator (green), and cathode (blue, plus sign), each about 20 nanometers in size. Below are their respective molecular structures

This is truly a revolutionary battery architecture,” said Wiesner, whose group’s paper, “Block Copolymer Derived 3-D Interpenetrating Multifunctional Gyroidal Nanohybrid for Electrical Energy Storage,” was published in Energy and Environmental Science, a publication of the Royal Society of Chemistry.

This three-dimensional architecture basically eliminates all losses from dead volume in your device,” Wiesner said. “More importantly, shrinking the dimensions of these interpenetrated domains down to the nanoscale, as we did, gives you orders of magnitude higher power density. In other words, you can access the energy in much shorter times than what’s usually done with conventional battery architectures.”

How fast is that? Wiesner said that, due to the dimensions of the battery’s elements being shrunk down to the nanoscale, “by the time you put your cable into the socket, in seconds, perhaps even faster, the battery would be charged.”

The architecture for this concept is based on block copolymer self-assembly, which the Wiesner group has employed for years in other devices, including a gyroidal solar cell and a gyroidal superconductor. Joerg Werner, Ph.D. ’15, lead author on this work, had experimented with self-assembling filtration membranes, and wondered if the same principles could be applied to carbon materials for energy storage.

Source: http://news.cornell.edu/