innovation

Mar 232017
 

via TV Tropes

Rewarded with a Nobel Prize in Chemistry in 2016, nanomachines provide mechanical work on the smallest of scales. Yet at such small dimensions, molecular motors can complete this work in only one direction. Researchers from the CNRS’s Institut Charles Sadron, led by Nicolas Giuseppone, a professor at the Université de Strasbourg, working in collaboration with the Laboratoire de mathématiques d’Orsay (CNRS/Université Paris-Sud), have succeeded in developing more complex molecular machines that can work in one direction and its opposite. The system can even be controlled precisely, in the same way as a gearbox.

The study was published in Nature Nanotechnology on March 20, 2017.

Molecular motors can produce cyclical mechanical movement using an external energy source, such as a chemical or light source, combined with Brownian motion (disorganized and random movement of surrounding molecules). However, nanomotors are exposed to molecular collisions on all sides, which complicates the production of directed and hence useful mechanical work. The first molecular motors from the 2000s used the principle of the “Brownian ratchet,” which like a notch on a cogwheel that prevents a mechanism from moving backwards, will bias Brownian movement so that the motor functions in only one direction. This makes it possible to provide useable work, but it does not allow for a change in direction.

The research team thus set out to find a solution for reversing this movement, which they did by connecting motors to molecular modulators (clutch subunits) using polymer chains (transmission subunits). A mathematical model has also been established to understand the behavior of this network.

When exposed to ultraviolet irradiation, the motors turn while the modulators remain immobile. The polymer chains thus wind around themselves, and contract like a rubber band that shortens as it is twisted. The phenomenon can be observed on a macroscopic scale, as the molecules form a material that contracts.

When the molecules are exposed to visible light, the motors stop and the modulators are activated. The mechanical energy stored in the polymer chains then rotates the modulators in the opposite direction of the original movement, and the material extends.

More spectacular still, the researchers were able to demonstrate that the rate and speed of the work produced can be carefully regulated through a combination of UV and visible light, like a gearbox functioning through modulations in frequency between the motors and modulators. The team is now attempting to use this study to develop photomechanical devices that can provide mechanical work controlled by light.

Learn more: Light-controlled gearbox for nanomachines

 

Mar 232017
 

A transparent piece of epoxy, left, compared to epoxy with e-waste reinforcement at right. A cryo-milling process developed at Rice University and the Indian Institute of Science simplifies the process of separating and recycling electronic waste. Courtesy of the Ajayan Research Group

Rice, Indian Institute researchers use cryo-mill to turn circuit boards into separated powders

Researchers at Rice University and the Indian Institute of Science have an idea to simplify electronic waste recycling: Crush it into nanodust.

Specifically, they want to make the particles so small that separating different components is relatively simple compared with processes used to recycle electronic junk now.

Chandra Sekhar Tiwary, a postdoctoral researcher at Rice and a researcher at the Indian Institute of Science in Bangalore, uses a low-temperature cryo-mill to pulverize electronic waste – primarily the chips, other electronic components and polymers that make up printed circuit boards (PCBs) — into particles so small that they do not contaminate each other.

Then they can be sorted and reused, he said.

The process is the subject of a Materials Today paper by Tiwary, Rice materials scientist Pulickel Ajayan and Indian Institute professors Kamanio Chattopadhyay and D.P. Mahapatra. 

The researchers intend it to replace current processes that involve dumping outdated electronics into landfills, or burning or treating them with chemicals to recover valuable metals and alloys. None are particularly friendly to the environment, Tiwary said.

“In every case, the cycle is one way, and burning or using chemicals takes a lot of energy while still leaving waste,” he said. “We propose a system that breaks all of the components – metals, oxides and polymers – into homogenous powders and makes them easy to reuse.”

The researchers estimate that so-called e-waste will grow by 33 percent over the next four years, and by 2030 will weigh more than a billion tons. Nearly 80 to 85 percent of often-toxic e-waste ends up in an incinerator or a landfill, Tiwary said, and is the fastest-growing waste stream in the United States, according to the Environmental Protection Agency.

The answer may be scaled-up versions of a cryo-mill designed by the Indian team that, rather than heating them, keeps materials at ultra-low temperatures during crushing.

Cold materials are more brittle and easier to pulverize, Tiwary said. “We take advantage of the physics. When you heat things, they are more likely to combine: You can put metals into polymer, oxides into polymers. That’s what high-temperature processing is for, and it makes mixing really easy.

“But in low temperatures, they don’t like to mix. The materials’ basic properties – their elastic modulus, thermal conductivity and coefficient of thermal expansion – all change. They allow everything to separate really well,” he said.

The test subjects in this case were computer mice – or at least their PCB innards. The cryo-mill contained argon gas and a single tool-grade steel ball. A steady stream of liquid nitrogen kept the container at 154 kelvins (minus 182 degrees Fahrenheit).

When shaken, the ball smashes the polymer first, then the metals and then the oxides just long enough to separate the materials into a powder, with particles between 20 and 100 nanometers wide. That can take up to three hours, after which the particles are bathed in water to separate them.

“Then they can be reused,” he said. “Nothing is wasted.”

Learn more: Pulverizing e-waste is green, clean — and cold

 

Mar 232017
 

Photo by: Ke Xu, graduate student, CFANS

Mercury is very toxic and can cause long-term health damage, but removing it from water is challenging. To address this growing problem, University of Minnesota College of Food, Agricultural and Natural Sciences (CFANS) Professor Abdennour Abbas and his lab team created a sponge that can absorb mercury from a polluted water source within seconds.

Thanks to the application of nanotechnology, the team developed a sponge with outstanding mercury adsorption properties where mercury contaminations can be removed from tap, lake and industrial wastewater to below detectable limits in less than 5 seconds (or around 5 minutes for industrial wastewater). The sponge converts the contamination into a non-toxic complex so it can be disposed of in a landfill after use. The sponge also kills bacterial and fungal microbes.

Think of it this way: If Como Lake was contaminated with mercury at the EPA limit, the sponge needed to remove all of the mercury would be the size of a basketball.

This is an important advancement for the state of Minnesota, as more than two thirds of the waters on Minnesota’s 2004 Impaired Waters List are impaired because of mercury contamination that ranges from 0.27 to 12.43 ng/L (the EPA limit is 2 ng/L). Mercury contamination of lake waters results in mercury accumulation in fish, leading the Minnesota Department of Health to establish fish consumption guidelines. A number of fish species store-bought or caught in Minnesota lakes are not advised for consumption more than once a week or even once a month. In Minnesota’s North Shore, 10 percent of tested newborns had mercury concentrations above the EPA reference dose for methylmercury (the form of mercury found in fish). This means that some pregnant women in the Lake Superior region, and in Minnesota, have mercury exposures that need to be reduced.  In addition, a reduced deposition of mercury is projected to have economic benefits reflected by an annual state willingness-to-pay of $212 million in Minnesota alone.

According to the US-EPA, cutting mercury emissions to the latest established effluent limit standards would result in 130,000 fewer asthma attacks, 4,700 fewer heart attacks, and 11,000 fewer premature deaths each year. That adds up to at least $37 billion to $90 billion in annual monetized benefits annually.

In addition to improving air and water quality, aquatic life and public health, the new technology would have an impact on inspiring new regulations. Technology shapes regulations, which in turn determine the value of the market. The 2015 EPA Mercury and Air Toxics Standards regulation was estimated to cost the industry around of $9.6 billion annually in 2020. The new U of M technology has a potential of bringing this cost down and make it easy for the industry to meet regulatory requirements.

Learn more: “Super sponge” promises effective toxic clean-up of lakes and more

 

Mar 232017
 

Binghamton University Electrical and Computer Science Assistant Professor Seokheun Choi is one of the co-authors of ‘Self-sustaining, solar-driven bioelectricity generation in micro-sized microbial fuel cell using co-culture of heterotrophic and photosynthetic bacteria.’
via Binghamton University

Researchers have taken the next step in the evolution of bacteria-powered energy. For the first time ever, researchers connected nine biological-solar (bio-solar) cells into a bio-solar panel. Then they continuously produced electricity from the panel and generated the most wattage of any existing small-scale bio-solar cells – 5.59 microwatts.

“Once a functional bio-solar panel becomes available, it could become a permanent power source for supplying long-term power for small, wireless telemetry systems as well as wireless sensors used at remote sites where frequent battery replacement is impractical,” said Seokheun “Sean” Choi, assistant professor of electrical and computer engineering, and co-author of the paper.

Choi is the corresponding author of the paper “Biopower generation in a microfluidic bio-solar panel,” which reported the findings.

“This research could also enable crucial understanding of the photosynthetic extracellular electron transfer processes in a smaller group of microorganisms with excellent control over the microenvironment, thereby enabling a versatile platform for fundamental bio-solar cell studies,” Choi said.

Xuejian Wei, a graduate student in the department, and Hankeun Lee, who will graduate from Binghamton in May, were also authors of the study.

The current research is the latest step in using cyanobacteria (which can be found in almost every terrestrial and aquatic habitat on the planet) as a source of clean and sustainable energy. Last year, the group took steps toward building a better bio-solar cell by changing the materials used in anodes and cathodes (positive and negative terminals) of the cell and also created a miniature microfluidic-based single-chambered device to house the bacteria instead of the conventional, dual-chambered bio-solar cells.

However, this time the group connected nine identical bio-solar cells in a 3×3 pattern to make a scalable and stackable bio-solar panel. The panel continuously generated electricity from photosynthesis and respiratory activities of the bacteria in 12-hour day-night cycles over 60 total hours.

“Bio-solar cell performance has improved significantly through miniaturizing innovative device architectures and connecting multiple miniature cells in a panel,” the report said. “This could result in barrier-transcending advancements in bio-solar cells that could facilitate higher power/voltage generation with self-sustainability, releasing bio-solar cell technology from its restriction to research settings, and translating it to practical applications in the real-world.”

Even with the breakthrough, a typical “traditional” solar panel on the roof of a residential house, made up of 60 cells in a 6×10 configuration, generates roughly 200 watts of electrical power at a given moment. The cells from this study, in a similar configuration, would generate about 0.00003726 watts.

So, it isn’t efficient just yet, but the findings open the door to future research of the bacteria itself.

“It is time for breakthroughs that can maximize power-generating capabilities/energy efficiency/sustainability,” Choi said. “The metabolic pathways of cyanobacteria or algae are only partially understood, and their significantly low power density and low energy efficiency make them unsuitable for practical applications. There is a need for additional basic research to clarify bacterial metabolism and energy production potential for bio-solar applications.”

Learn more: Researchers generate clean energy using bacteria-powered solar panel

 

Mar 222017
 

via NDTV Food

Doctors may soon be able to detect and monitor a patient’s cancer with a simple blood test, reducing or eliminating the need for more invasive procedures, according to Purdue University research.

W. Andy Tao, a professor of biochemistry and member of the Purdue University Center for Cancer Research and colleagues identified a series of proteins in blood plasma that, when elevated, signify that the patient has cancer. Their findings were published in the early edition of the Proceedings of the National Academy of Sciences.

Tao’s work was done with samples from breast cancer patients, but it is possible the method could work for any type of cancer and other types of diseases. The work relies on analysis of microvesicles and exosomes in blood plasma.

Protein phosphorylation, the addition of a phosphate group to a protein can lead to cancer cell formation. So phosphorylated proteins, known as phosphoproteins, have been seen as prime candidates for cancer biomarkers. Until now, however, scientists weren’t sure identification of phosphoproteins in blood was possible because the liver releases phosphatase into the bloodstream, which dephosphorylates proteins.

“There are so many types of cancer, even multiple forms for different types of cancer, that finding biomarkers has been discouraging,” Tao said. “This is definitely a breakthrough, showing the feasibility of using phosphoproteins in blood for detecting and monitoring diseases.”

Tao and his colleagues found nearly 2,400 phosphoproteins in a blood sample and identified 144 that were significantly elevated in cancer patients. The study compared 1-milliliter blood samples from 30 breast cancer patients with six healthy controls.

The researchers used centrifuges to separate plasma from red blood cells, and high-speed and ultra-high-speed centrifuges to further separate microvesicles and exosomes. Those particles, which are released from cells and enter the bloodstream, may play a role in intercellular communication and are thought to be involved in metastasis, spreading cancer from one place to another in the body. They also encapsulate phosphoproteins, which Tao’s team identified using mass spectrometry.

“Extracellular vesicles, which include exosomes and microvesicles, are membrane-encapsulated. They are stable, which is important,” Tao said. “The samples we used were 5 years old, and we were still able to identify phosphoproteins, suggesting this is a viable method for identifying disease biomarkers.”

A simple blood test for cancer would be far less invasive than scopes or biopsies that remove tissue. A doctor could also regularly test a cancer patient’s blood to understand the effectiveness of treatment and monitor patients after treatment to see if the cancer is returning.

“There is currently almost no way to monitor patients after treatment,” Tao said. “Doctors have to wait until cancer comes back.”

Timothy Ratliff, director of the Purdue University Center for Cancer Research, said the findings are promising for early detection of cancer.

“The vesicles and exosomes are present and released by all cancers, so it could be that there are general patterns for cancer tissues, but it’s more likely that Andy will develop patterns associated with different cancers. It’s really exciting,” Ratliff said. “Early detection in cancer is key and has been shown to clearly reduce the death rate associated with the disease.”

Tao plans to analyze increased levels of phosphoproteins in various types of cancer to determine whether there are patterns that would signify the type of cancer a patient has. His company, Tymora Analytical, is also developing technology that would allow doctors to insert blood samples onto a cartridge and analyze phosphoproteins present, eliminating the need for ultra-high-speed centrifuges that aren’t practical in clinical settings.

Learn more: Breakthrough discovery may make blood test feasible for detecting cancer

Mar 222017
 

Deyu Tu , informationskodning, 2017

Organic light-emitting devices and printed electronics can be connected to a socket in the wall by way of a small, inexpensive organic converter, developed in a collaboration between Linköping University and Umeå University.

Printed electronics and organic light-emitting devices now perform at levels sufficient for a number of eco-friendly, energy-efficient applications. Previously the idea has been to drive the organic electronics using solar cells, batteries or wireless transformers, which works well in many cases. But for fixed installations like lighting, signage or UV-blocking windows, it is convenient to use a wall socket. Until now this has not been possible, because the high voltage damages the electronics.

Thin-film transistors

Docent Deyu Tu from LiU’s Division of Information Coding has led a project where colleagues at Umeå University joined forces to find a solution to this problem. And they have now been able to demonstrate an organic converter that makes it possible to drive organic light-emitting devices with high luminescence, and to charge supercapacitors, both using electricity from an ordinary wall socket.

The converter consists of diode-connected organic thin-film transistors, operated at high voltages up to 325 V, with the capacity to transform high alternating current (AC) to a selected direct current (DC).

“For the first time in the world we have been able to demonstrate an AC/DC converter in organic electronics that functions at voltages above 300 V,” says Deyu Tu.

“Our converter paves the way for a wave of flexible, thin, cost-effective and eco-friendly solutions for the electronics of the future.”

A pioneer work

This is a pioneer work of organic AC/DC converters, a first stage to prove the concept of organic power electronics. To be used in real products, the power conversion efficiency needs to be improved.

”We have initiated the follow-up work to deal with this issue”, says Deyu Tu.

Learn more: Organic electronics can use power from socket

 

Mar 222017
 

NANOTRICKS: Bengt Svensson and co-workers are currently producing the solar cells of the future out of nano-materials, which will capture sunlight in both the red and the blue spectrum. That means that the efficiency can be doubled. In addition, these solar cells will be environment-friendly and be produced solely from materials that are in great abundance on Earth. Photo: Yngve Vogt

In the future, solar cells can become twice as efficient by employing a few smart little nano-tricks.

Researchers are currently developing the environment-friendly solar cells of the future, which will capture twice as much energy as the cells of today. The trick is to combine two different types of solar cells in order to utilize a much greater portion of the sunlight.

“These are going to be the world’s most efficient and environment-friendly solar cells. There are currently solar cells that are certainly just as efficient, but they are both expensive and toxic. Furthermore, the materials in our solar cells are readily available in large quantities on Earth. That is an important point,” says Professor Bengt Svensson of the Department of Physics at the University of Oslo (UiO) and Centre for Materials Science and Nanotechnology (SMN).

Svensson is one of Norway’s leading researchers on solar energy, and for many years, he has headed major research projects at the Micro and Nanotechnology Laboratory (MiNaLab), which is jointly owned by UiO and the Foundation for Scientific and Industrial Research at the Norwegian Institute of Technology (Sintef). Using nanotechnology, atoms and molecules can be combined into new materials with very special properties.

The physicists are now making use of the very best of nanotechnology and will develop new solar cells in the European research project, Solhet (High-performance tandem heterojunction solar cells for specific applications), which is a collaborative project involving UiO, the Institute for Energy Technology (IFE) at Kjeller, Norway and the University Polytehnica of Bucharest, together with two other Romanian institutions. The Solhet team at UiO comprises Raj Kumar (Post-doctor), Kristin Bergum (Researcher), Edouard Monakhov (professor) and Svensson.

Modern solar cells

Their goal is to utilize even more of the spectrum of sunlight than is possible at present. Ninety-nine per cent of today’s solar cells are made from silicon, which is one of the most common elements on Earth. Unfortunately, silicon solar cells only utilize 20 per cent of the sunlight. The world record is 25 per cent, but these solar cells are laced with rare materials that are also toxic. The theoretical limit is 30 per cent. The explanation for this limit is that silicon cells primarily capture the light waves from the red spectrum of sunlight. That means that most of the light waves remain unutilized.

The new solar cells will be composed of two energy-capturing layers. The first layer will still be composed of silicon cells.

“The red wavelengths of sunlight generate electricity in the silicon cells in a highly efficient manner. We’ve done a great deal of work with silicon, so there is only a little more to gain.”

The new trick is to add another layer on top of the silicon cells. This layer is composed of copper oxide and is supposed to capture the light waves from the blue spectrum of sunlight.

“We have managed to produce a copper oxide layer that captures three per cent of the energy from the sunlight. The world record is nine per cent. We are currently working intensely to increase that percentage to twenty per cent. The combination of silicon cells in the one layer and copper oxide cells in the other means that we’ll be able to absorb far more light and thereby reduce the energy loss. With this combination, we can utilize 35 to 40 per cent of the sunlight,” emphasizes Bengt Svensson.

There will also be other layers in the solar cell panel. On the back surface, a protective glass layer will be deposited, along with a metal layer that conducts the electricity out of the solar cell. The front side will have an antireflective coating, so that the light rays are captured rather than reflected away.

The solar cell panel will be very thin. The thickness of the individual layers will vary between a hundred and a thousand nanometres. A thousand nanometres equals one micrometre. A single hair is ten times thicker. One of the trickiest moves is to create a special layer that will be as thin as one to two nanometres. Apollon will have more to say about that, but first a few theoretical explanations are in order.

Create conducting electrons

All solar cell materials are composed of semiconductor materials. Semiconductors have very special electrical properties. These electrical properties are determined by the band gap.

The band gap gives an indication of how much energy will be required in order to create conducting electrons.

Materials without any band gap width conduct electricity. Materials with a big band gap do not conduct electricity. Semiconductors are materials with a moderate band gap, which means that they only partially conduct electricity.

Nanotechnology is used to design materials with a very specific band gap.

When the photons, i.e. light particles from the sun, strike the solar cell, energy is delivered to the solar cell. This energy impels an electron through the band gap and into what is called the conduction band, where the electrons can be gathered up and removed as energy.

The electrons leave behind electron holes. Both the electron and the electron hole can conduct electricity.

“The challenge is to develop cobber oxide with a band gap that is precisely large enough so that the electrons can be captured before they fall back down to their electron holes. We’ve been working on this for a number of years, and we are beginning to understand how this can be done.”

Although time is scarce, there is a ray of light: if the electrons are removed from the electron holes for more than a millisecond, it is possible to capture them.

Chaos between the layers

One of the unsolved problems in the new solar cells is the boundary areas between the different layers.

“When the layers are deposited on top of each other, chemical reactions take place that reduce or in the worst case destroy the solar cells.”

One problem is the boundary surface between the solar cell layer that captures energy from the blue light and the outermost layer of zinc oxide that both protects the cell and conducts the electricity out of the cell. Unfortunately, the electrons die at this boundary surface.

The biggest challenge is the boundary surface between the silicon layer, which captures energy from the red light, and the copper oxide layer, which captures energy from the blue light.

The two solar cell layers each function well on their own, and that is where Apollon gets to the point. The problem arises when the layers are deposited together. That is when the adverse chemical changes occur.

“The chemical changes can change the band gap. When the band gap is wrong or defective, the electron holes are filled again before the electrons can be captured.”

One possibility is to deposit other substances between the layers so that the chemical changes are minimized.

There are many ways to create this buffer layer.

“We want to use a hydrogen-rich material. That can pacify the chemical changes and increase the lifetime of the electrons and electron holes.”

Another possibility is to lace the buffer with gallium oxide, but this substance is not exactly environment-friendly. Pure gallium is toxic.

By making the buffer as thin as just one to two nanometres, the chemical effect is minimized.

“The thicker the intermediate layer, the more electrons will be inhibited underway. That destroys the electrical capacity. If the electrons are inhibited in the buffer layer, the solar cells no longer function.”

From theory to practice

The theoretical modelling about how the buffer layer ought to appear is done at the University Polytehnica in Bucharest.

“They are very good at theoretical modelling,” says Bengt Svensson.

Professor Laurentiu Fara at the University Polytehnica in Bucharest tells Apollon that, among other things, they have calculated and simulated the optimal thickness of the solar cell layers, the best possible way for the layers to be deposited together, and how it is theoretically possible to extract the greatest possible amount of electricity.

“We have great expectations that the solar cells can become reliable and profitable, but we’re very aware that a great deal of hard work still remains,” emphasizes Laurentiu Fara.

UiO is performing the experimental part of the work. IFE will develop the prototype for producing the solar cells in great volumes. In addition, IFE is the main coordinator for the whole research project.

“We have already worked with silicon-based solar cell technology for many years in collaboration with the Norwegian solar cell industry. Now we’ll look into how the two solar cell layers can be adapted to each other in order to get the greatest amount of power out of the whole solar cell and into how the two cells affect each other both optically and electrically,” say Sean Erik Foss and Ørnulf Nordseth at IFE.

They tell us that very many researchers and technology firms are working now on the new type of solar cells with silicon in the bottom layer and a layer of “more exotic materials” on top.

The Romanian solar cell company, Wattrom, intends to show that it is possible to manufacture the new solar cells.

“The technology is inexpensive, it can easily be scaled up to large volumes, and it’s not more expensive to produce solar cells out of copper oxide than out of silicon,” says Bengt Svensson.

He thinks the solar cells will be very profitable to produce because the utilization of the light spectrum will be high.

“Even a tenth of a per cent increase in the efficiency yields substantial economic gains for the solar cell industry, but we’re talking here about a much more dramatic increase in efficiency.”

Moreover, the solar cells will function well even in those parts of the globe where the sun is low on the horizon, such as Scandinavia.

He says that efficient solar cells can change the whole way of thinking about energy in the future.

“We have an enormous resource in the sun. If we could utilize the sunlight one hundred per cent, an hour of the annual sunlight would meet all the energy needs on Earth. Thus, the potential is enormous. In principle, it is possible to meet the whole world’s energy needs with sunlight. Solar energy is actually the renewable energy source that has the greatest potential of all. That is what we want to utilize,” says Bengt Svensson.

Learn more: The world’s most efficient and environment-friendly solar cells

Mar 212017
 

Sandia National Laboratories chemical engineer and lead paper author Aashish Priye offers a view into the Zika box prototype, along with co-authors Sara Bird, a virologist, center, and Cameron Ball, a biomedical engineer. (Photo by Randy Wong)

Add rapid, mobile testing for Zika and other viruses to the list of things that smartphone technology is making possible. Researchers at Sandia National Laboratories have developed a smartphone-controlled, battery-operated diagnostic device that weighs under a pound, costs as little as $100 and can detect Zika, dengue and chikungunya within 30 minutes.

Testing for these mosquito-borne viruses currently requires a laboratory, and patients can wait days for results. The tests require instruments that are roughly the size of a microwave oven and can cost up to $20,000. This makes rapid testing unrealistic for limited-resource clinics in developing countries where the viruses are prevalent.

The Sandia team describes its rapid-testing prototype in a paper published this week in the journal Scientific Reports, “A smartphone-based diagnostic platform for rapid detection of Zika, chikungunya and dengue viruses.”

Smartphone technology is a key feature of the device. “In addition to creating an app that serves as a simple interface to operate the device, we were able to adapt smartphone camera sensors to replace traditional laboratory sample analysis tools, allowing for unprecedented mobility,” chemical engineer and lead author Aashish Priye said.

Laboratory in a box

The Sandia team’s device is based on the loop-mediated isothermal amplification (LAMP) diagnostic method, which eliminates the need to process a biological sample, such as blood or urine, before testing. Conventional viral testing involves transporting a sample to a laboratory, extracting DNA or RNA from it and then multiplying the genetic materials through a process called polymerase chain reaction (PCR). This process involves heating and cooling the sample many times, so that any viral DNA/RNA in the sample is replicated enough to be detected.

Repeatedly heating and cooling the sample is power intensive and demands the complexity of PCR machines. Detection of the copied viral material also requires expensive components such as fluorimeters. The complexity and expense of traditional PCR machines have been major hurdles in moving PCR devices outside of laboratories and into the clinics where they are most needed.

Like PCR, LAMP copies viral DNA/RNA, but without the heating and cooling cycle, a heavy-duty power source isn’t needed. The addition of a few carefully designed biochemical agents allows a LAMP box to test a sample that is heated only once to 65 degrees Celsius (150 degrees Fahrenheit) for half an hour.

LAMP also eliminates the need for extra sample preparation before testing. “We’ve demonstrated that the chemistry we’re using can amplify viral RNA directly from raw, unprocessed samples,” said Sandia chemical engineer and project lead Robert Meagher. “That is the ideal for a point-of-care testing scenario because you don’t want to have extra equipment for isolating DNA or RNA.”

Meagher and his team previously developed a method to combine LAMP with an additional detection technique so they could test multiple viruses simultaneously. This other technique, known as quenching of unincorporated amplification signal reporters (QUASR), involves tagging fragments of synthesized viral DNA called primers with fluorophores — molecules that emit bright light signals. The primers incorporate into the heated and amplified sample DNA. QUASR then causes samples containing viral DNA/RNA to appear bright, while negative reactions remain dark.

One-touch testing

For the Zika project, Meagher’s team developed a novel algorithm that allows a smartphone sensor to act as a fluorimeter, detecting QUASR LAMP light signals if they appear. LAMP works so simply that the user need only place the smartphone on top of the LAMP box and open an app. The app turns on the heater to initiate the LAMP reaction.

Once the 30-minute testing period is up, the smartphone photographs the sample. The app then employs a novel image analysis algorithm to accurately determine the color and brightness of the glow emitted from the LAMP reaction. This smartphone-based image analysis offers much greater detection certainty than the lab technician’s naked eye.

Zika virus has been linked to severe fetal abnormalities, including microcephaly and congenital blindness, as well as neurological disorders that can strike people at any age. By enabling diagnosis in half an hour, the device could help clinicians make faster decisions about patient care and isolation, and rapidly alert public health authorities so they can take measures to prevent spread of the virus.

Furthermore, Zika, dengue and chikungunya are spread by the same mosquito type and have similar early symptoms. Sandia’s prototype diagnostic tool could enable care providers to test quickly for all three at the same time, preventing misdiagnoses. The same tool can also be adapted to detect other human or animal pathogens.

The cost of making a LAMP box prototype to test for these viruses depends largely on the cost of the phone selected for use with it. “There are billions of smartphones in the world, even in developing countries, and this tool doesn’t require the highest-end smartphone on the market,” Priye said. “It only needs to have an optical sensor and be able to run the app.” The smartphone used in Sandia’s successful tests of the prototype cost a mere $20. Ultra-accessible and ultra-portable, the Zika box prototype could one day become a staple in point-of-care clinics worldwide.

Learn more: Testing for Zika virus: there’s an app for that

 

Mar 212017
 

Researcher Anna Ottenhall compares samples after running dirty water through the wood-based antibacterial filter. (Photo: David Callahan)

What can the forests of Scandinavia possibly offer to migrants in faraway refugee camps? Clean water may be one thing.

A bacteria-trapping material developed from wood by researchers at KTH Royal Institute of Technology is now being tested for use as a water purification filter. The aim is to use it in places where there is no infrastructure or clean water supply.

The material, which combines wood cellulose with a positively-charged polymer, can trap bacteria by attracting and binding the bacteria to the material surface. It shows promise for bandages, plasters and packaging that kill bacteria without releasing toxins into the environment.

Led by Professor Monica Ek, the researchers at KTH are investigating whether the material can enable portable on-site water treatment where no facilities or wells exist to meet demand.

“Our aim is that we can provide the filter for a portable system that doesn’t need electricity – just gravity – to run raw water through it,” says Anna Ottenhall, a PhD student at KTH’s School of Chemical Science and Engineering. “The great idea is that we are trapping the bacteria and removing them from the water by our positively-charged filter. The bacteria trapping material does not leach any toxic chemicals into the water, as many other on-site purification methods do.”

Her co-supervisor, Josefin Illergård, has been working with  antibacterial fibers from wood cellulose  for about a decade. “We had this fantastic material that is antibacterial and can be used in different ways, and we wanted to see how to use it in a way that truly makes a difference – a way that addresses a big problem in the world,” Illergård says.

Illergård says the fibres are dipped in a positively-charged polymer solution that makes the surface becomes positively charged. Bacteria and viruses are negatively charged and therefore stick to the positively-charged polymer surface. From there, they cannot free themselves and reproduce, and as a result they die.

“One of the advantages of surfaces covered with polymers is that bacteria will not develop any resistance,” she says.

After it is used, the filter can be burned.

Learn more: Water filter from wood offers portable, eco-friendly purification in emergencies

 

Mar 212017
 

University of Utah materials science and engineering professor Ashutosh Tiwari and has team have an inexpensive and bio-friendly material that can generate electricity through a thermoelectric process involving heat and cold air. In this graphic, the heat from a hot stove, coupled with the cooler water or food in a cooking pot, could generate enough electricity to charge a cellphone.
PHOTO CREDIT: Ashutosh Tiwari

Thanks to the discovery of a new material by University of Utah engineers, jewelry such as a ring and your body heat could generate enough electricity to power a body sensor, or a cooking pan could charge a cellphone in just a few hours.

The team, led by University of Utah materials science and engineering professor Ashutosh Tiwari, has found that a combination of the chemical elements calcium, cobalt and terbium can create an efficient, inexpensive and bio-friendly material that can generate electricity through a thermoelectric process involving heat and cold air.

Their findings were published in a new paper March 20 in the latest issue of Scientific Reports. The first author on the paper is University of Utah materials science and engineering postdoctoral researcher, Shrikant Saini.

Thermoelectric effect is a process where the temperature difference in a material generates an electrical voltage. When one end of the material is hot and the other end is cold, charge carriers from the hot end move through the material to the cold end, generating an electrical voltage. The material needs less than a one-degree difference in temperature to produce a detectable voltage.

For years, researchers have been looking for the right kind of material that makes the process more efficient and produces more electricity yet is not toxic. There are other materials that can generate power this way, such as cadmium-, telluride- or mercury-based materials, but those are toxic to humans. The unique advantage to this new material by Tiwari’s team is that it is inexpensive to produce and, mostly importantly, bio-friendly and eco-friendly while still being efficient at generating electricity, Tiwari says. Therefore, it could be safe to use with humans.

“There are no toxic chemicals involved,” he says. “It’s very efficient and can be used for a lot of day-to-day applications.”

The applications for this new material are endless, Tiwari says. It could be built into jewelry that uses body heat to power implantable medical devices such as blood-glucose monitors or heart monitors. It could be used to charge mobile devices through cooking pans, or in cars where it draws from the heat of the engine. Airplanes could generate extra power by using heat from within the cabin versus the cold air outside. Power plants also could use the material to produce more electricity from the escaped heat the plant generates.

“In power plants, about 60 percent of energy is wasted,” postdoctoral researcher, Saini, says. “With this, you could reuse some of that 60 percent.”

Finally, Tiwari says it could be used in developing countries where electricity is scarce and the only source of energy is the fire in stoves.

Learn more: LUST FOR POWER

 

Mar 212017
 

Teaching critical thinking skills in a humanities course reduces student beliefs in “pseudoscience” — such as believing in the underwater civilization of Atlantis. Image credit: Jerrye and Roy Klotz (Own work)

A recent study by North Carolina State University researchers finds that teaching critical thinking skills in a humanities course significantly reduces student beliefs in “pseudoscience” that is unsupported by facts.

“Given the national discussion of ‘fake news,’ it’s clear that critical thinking – and classes that teach critical thinking – are more important than ever,” says Anne McLaughlin, an associate professor of psychology at NC State and co-author of a paper describing the work.

“Fundamentally, we wanted to assess how intentional you have to be when teaching students critical thinking,” says Alicia McGill, an assistant professor of history at NC State and co-author of the paper. “We also wanted to explore how humanities classes can play a role and whether one can assess the extent to which critical thinking instruction actually results in improved critical thinking by students.

“This may be especially timely, because humanities courses give students tools they can use to assess qualitative data and sort through political rhetoric,” McGill says. “Humanities also offer us historical and cultural perspective that allow us to put current events into context.”

For this study, the researchers worked with 117 students in three different classes. Fifty-nine students were enrolled in a psychology research methods course, which taught statistics and study design, but did not specifically address critical thinking. The other 58 students were enrolled in one of two courses on historical frauds and mysteries – one of which included honors students, many of whom were majors in science, engineering and mathematics disciplines.

The psychology class served as a control group. The two history courses incorporated instruction explicitly designed to cultivate critical thinking skills. For example, students in the history courses were taught how to identify logical fallacies – statements that violate logical arguments, such as non sequiturs.

At the beginning of the semester, students in all three courses took a baseline assessment of their beliefs in pseudoscientific claims. The assessment used a scale from 1 (“I don’t believe at all.”) to 7 (“I strongly believe.”).

Some of the topics in the assessment, such as belief in Atlantis, were later addressed in the “historical frauds” course. Other topics, such as the belief that 9/11 was an “inside job,” were never addressed in the course. This allowed the researchers to determine the extent to which changes in student beliefs stemmed from specific facts discussed in class, versus changes in a student’s critical thinking skills.

At the end of the semester, students took the pseudoscience assessment again.

The control group students did not change their beliefs – but students in both history courses had lower beliefs in pseudoscience by the end of the semester.

Students in the history course for honors students decreased the most in their pseudoscientific beliefs; on average, student beliefs dropped an entire point on the belief scale for topics covered in class, and by 0.5 points on topics not covered in class. There were similar, but less pronounced, changes in the non-honors course.

“The change we see in these students is important, because beliefs are notoriously hard to change,” says McLaughlin. “And seeing students apply critical thinking skills to areas not covered in class is particularly significant and heartening.”

“It’s also important to note that these results stem from taking only one class,” McGill says. “Consistent efforts to teach critical thinking across multiple classes may well have more pronounced effects.

“This drives home the importance of teaching critical thinking, and the essential role that humanities can play in that process,” McGill says. “This is something that NC State is actively promoting as part of a universitywide focus on critical thinking development.”

Learn more: Critical Thinking Instruction in Humanities Reduces Belief in Pseudoscience

 

Mar 202017
 

via Imperial College London

The first in a new class of gene-silencing drugs, known as inclisiran, has halved cholesterol levels in patients at risk of cardiovascular disease.

The findings come from the largest trial yet to test the safety and effectiveness of this kind of therapy. The technique, known as RNA interference (RNAi) therapy, essentially ‘switches off’ one of the genes responsible for elevated cholesterol.

We appear to have found a versatile, easy-to-take, safe, treatment that provides sustained lowering of cholesterol levels and is therefore likely to reduce the risk of cardiovascular disease, heart attacks, and stroke.

– Professor Kausik Ray

School of Public Health

Researchers from Imperial College London and their colleagues, who conducted the trial, say the twice-a-year treatment could be safely given with or without statins, depending on individual patient needs. Eventually, inclisiran could help to reduce the risk of heart attacks and stroke related to high cholesterol.

“These initial results are hugely exciting for patients and clinicians,” said Professor Kausik Ray, lead author of the study from the School of Public Health at Imperial.

“We appear to have found a versatile, easy-to-take, safe, treatment that provides sustained lowering of cholesterol levels and is therefore likely to reduce the risk of cardiovascular disease, heart attacks, and stroke. These reductions are over and above what can be already be achieved with statins alone or statins plus ezetemibe, another class of cholesterol-lowering drug.

Elevated levels of low-density lipoprotein (LDL) cholesterol can lead to cardiovascular disease and blood vessel blockage, leading to an increased risk heart attacks and stroke in patients.

Statins are currently the standard treatment for high cholesterol, combined with exercise and healthy diet, as they reduce levels in the blood and therefore help to prevent heart attacks and stroke.

However, many patients are unable to tolerate the highest doses and they need to be taken consistently. Forgetting to take them or taking them infrequently reduces the expected benefit from these treatments. Also, in some patients cholesterol levels can remain high despite being given the maximum doses of statins.

Now, this new phase 2 clinical trial has confirmed the effectiveness of injecting inclisiran for reducing cholesterol that can be taken alone or potentially combined with statins for maximum effect.

In the study, researchers gave 497 patients with high cholesterol and at high risk of cardiovascular disease either inclisiran at varying doses, or placebo. Seventy-three per cent of these patients were already taking statins, and 31 per cent were taking ezetimibe. Participants, who were recruited from Canada, USA, Germany, Netherlands, and the UK, were excluded if they were taking monoclonal antibodies for cholesterol lowering.

Lower risk patients could in theory have once yearly injections whereas higher risk patients might have two injections a year.

– Professor Kausik Ray

School of Public Health

Patients were given different doses of inclisiran or placebo via subcutaneous injection, either via a single dose, or via a dose on day one and another at three months. They were followed up regularly for a subsequent eight months and tested for blood cholesterol and side effects.

The researchers found that just one month after receiving a single treatment of inclisiran, participants’ LDL cholesterol levels had reduced by up to 51 per cent.

In those on a single dose of 300 mg, cholesterol levels were reduced by 42 per cent at six months. In the matched placebo group, cholesterol levels had increased by two per cent within that time frame.

In those on two doses of 300 mg, cholesterol levels were reduced by up to 53 per cent at six months. Moreover, cholesterol levels had gone down for all patients in this group, and 48 per cent of them had achieved cholesterol levels (below 50 mL/dL).

In all patients, cholesterol levels stayed lower for at least eight months. No extra side effects were seen in the study group compared to the placebo group.

Statin combinations

The study will now follow up patients for a further four months (one year total follow up).

The results from this trial, known as ORION-1, are published in the New England Journal of Medicine, and are presented today at the American College of Cardiology’s 66th Annual Scientific Session in Washington.

Giving inclisiran up to twice yearly at a GP surgery, much in the same way flu vaccinations are provided, might be more effective.

– Professor Kausik Ray

School of Public Health

The authors say the results show the drug acts quickly to reduce cholesterol levels by as early as two weeks post-injection, while also giving a prolonged effect when given in two doses over a year. Therefore, the next step is to conduct an extended study, using more patients and for a longer period of time, to determine whether these reductions in cholesterol translate into a reduction in heart attacks and strokes. Professor Ray said: “We are keen to enter the next phase of development to assess long-term safety and to see how this novel approach might translate into improvements in patient health.”

Aside from its effectiveness, the authors point out that because inclisiran acts on a different biological pathway to statins, the two drugs would likely be combined for the best results. Professor Ray said: “Even the single dose of inclisiran appears to lower cholesterol by 35-40% at eight months. We could essentially experiment with how often to give the drug based on levels of cardiovascular risk for each patient. Lower risk patients could in theory have once yearly injections whereas higher risk patients might have two injections a year.”

The authors emphasise that because this is an early-phase study, and because this is one of the first clinical studies on this type of drug, more research is needed before it can go to market.

He added: “The effectiveness of statins and other cholesterol-lowering treatments such as monoclonal antibodies relies on patients’ ability to take them consistently. Therefore, giving inclisiran up to twice yearly at a GP surgery, much in the same way flu vaccinations are provided, might be more effective.”

“We believe that these clinical visits might only be twice a year at most, so ultimately, they are more convenient and more effective for patients and their health.”

Learn more: New ‘gene silencer’ drug injections reduce cholesterol by 50% in clinical trial

 

Mar 202017
 

via Pixabay

A new computer software programme has the potential to lip-read more accurately than people and to help those with hearing loss, Oxford University researchers have found.

Watch, Attend and Spell (WAS), is a new artificial intelligence (AI) software system that has been developed by Oxford, in collaboration with the company DeepMind.

The AI system uses computer vision and machine learning methods to learn how to lip-read from a dataset made up of more than 5,000 hours of TV footage, gathered from six different programmes including Newsnight, BBC Breakfast and Question Time. The videos contained more than 118,000 sentences in total, and a vocabulary of 17,500 words.

The research team compared the ability of the machine and a human expert to work out what was being said in the silent video by focusing solely on each speaker’s lip movements. They found that the software system was more accurate compared to the professional. The human lip-reader correctly read 12 per cent of words, while the WAS software recognised 50 per cent of the words in the dataset, without error. The machine’s mistakes were small, including things like missing an “s” at the end of a word, or single letter misspellings.

The software could support a number of developments, including helping the hard of hearing to navigate the world around them.  Speaking on the tech’s core value, Jesal Vishnuram, Action on Hearing Loss Technology Research Manager, said: ‘Action on Hearing Loss welcomes the development of new technology that helps people who are deaf or have a hearing loss to have better access to television through superior real-time subtitling.

‘It is great to see research being conducted in this area, with new breakthroughs welcomed by Action on Hearing Loss by improving accessibility for people with a hearing loss. AI lip-reading technology would be able to enhance the accuracy and speed of speech-to-text especially in noisy environments and we encourage further research in this area and look forward to seeing new advances being made.’

Commenting on the potential uses for WAS Joon Son Chung, lead-author of the study and a graduate student at Oxford’s Department of Engineering, said: ‘Lip-reading is an impressive and challenging skill, so WAS can hopefully offer support to this task – for example,  suggesting hypotheses for professional lip readers to verify using their expertise. There are also a host of other applications, such as dictating instructions to a phone in a noisy environment, dubbing archival silent films, resolving multi-talker simultaneous speech and improving the performance of automated speech recognition in general.’

Learn more: New computer software programme excels at lip reading

 

Mar 202017
 

Numerical and theoretical analyses describing the performance of a 2D disordered array of nanoholes in channel transfer form far-field input to SPP output.*
* a) A 2D array of periodic nanoholes patterned on a metal film. Black dots indicate the positions of the holes. SPPs generated by a normally incident plane wave propagates along y-direction. Scale bar, 2 mm. (b) A 1D array of nanoholes patterned on a metal film. The incident wave whose wavefront is properly shaped focuses the SPPs generated at the nanoholes at a target spot on a sampling line (Z). (c) A 2D array of disordered nanoholes patterned on a metal film. Ordinary planar incident waves generate speckled SPPs. The blue, red and green curves at the sampling line are the SPP fields originating from the representative far-field illumination of the blue, red and green rectangular areas, respectively. The wavelength of the light source was 620 nm. The SPPs were uncorrelated if the centre-to-centre distance between two neighbouring illuminations was larger than the characteristic length lc described in the main text. (d) The same pattern of nanoholes as (c), but the correct choice of wavefront for the illuminations at the blue, red and green rectangular areas can cause the SPPs to constructively interfere at the target point (black curve). All the results displayed here were derived from the numerical simulations using the finite-difference time-domain (FDTD) method (see Supplementary Note 1 for details). (e) Expected enhancement factor for channel number.

Researchers from the Center for Molecular Spectroscopy and Dynamics (CMSD) increase the number of communication channels

Microprocessors play a pivotal role in computers and have steadily increased the speed of information processing over the past several decades. However, due to technical limitations such as heat generation due to integration, the processing speed of semiconductors has remained at several gigahertz (GHz) for the past decade. As a current alternative to this, many microprocessors are used in parallel, but the electrical connection between the processors is slow, creating a bottleneck for data transfer. To solve this problem, many studies have been conducted to merge processors by using optical signals which are several hundred times faster than electrical signals.

CHOI Wonshik, Associate Director of the CMSD, lead the research team that created an innovative device. The team discarded with the conventional method of periodically arranging the nano antennas. Instead, they devised disordered arrangement of the antennas to minimize redundancy between the antennas and enabled each antenna to function independently. As a result, the device can provide 40 times wider bandwidth than existing antennas periodically arranged. “We are proposing a new way to connect nanoscale microprocessors to ultra-high-speed optical communications,” commented Dr. Choi. The research will appear in the March edition of Nature Communications.

The team used surface plasmons to mediate optoelectronic signaling. At nano antennas, optical signals are converted to surface plasmons, which then propagate through metal surface as electric signals. The researchers randomly arranged the nano antennas, and the surface plasmons generated at each antenna underwent multiple scattering to minimize redundancy between the antennas. In this way, each of the antennas can be used independently, resulting in a substantial increase in the effective number of antennas to more than 40 times. An increase in the number of antennas means an increase in the number of multiple input channels in the MIMO communication, which leads to an increase in the information transmission bandwidth.


? Expected enhancement factor for channel number.

To exploit the benefit of disordered arrangement of antennas, the team had to resolve an innate problem. Random multiple scattering by disorderly arranged nano antennas is unpredictable, and cannot be used for information transfer without special measure. The researchers analyzed the patterns of multiple-scattered surface plasmons for various optical inputs and found a particular optical input signal that could send the desired signal to a particular microprocessor. The spatial light modulator was used to generate the identified optical input signal, and the surface plasmon could be controlled freely. “Using this,” offered Doctor Choi. “We proved that we can transmit signals to six different microprocessors at the same time and proved that optical images are converted into plasmons.”

Learn more: IBS create a multi-channel nano-optical device dramatically increasing the parallel processing speed of microprocessors

 

Mar 192017
 

An example of a gold foil peeled from single crystal silicon. Reprinted with permission from Naveen Mahenderkar et al., Science [355]:[1203] (2017)

Some day, your smartphone might completely conform to your wrist, and when it does, it might be covered in pure gold, thanks to researchers at Missouri S&T.

Writing in the March 17 issue of the journal Science, the S&T researchers say they have developed a way to “grow” thin layers of gold on single crystal wafers of silicon, remove the gold foils, and use them as substrates on which to grow other electronic materials. The research team’s discovery could revolutionize wearable or “flexible” technology research, greatly improving the versatility of such electronics in the future.

According to lead researcher Jay A. Switzer, the majority of research into wearable technology has been done using polymer substrates, or substrates made up of multiple crystals. “And then they put some typically organic semiconductor on there that ends up being flexible, but you lose the order that (silicon) has,” says Switzer, Donald L. Castleman/FCR Endowed Professor of Discovery in Chemistry at S&T.

Because the polymer substrates are made up of multiple crystals, they have what are called grain boundaries, says Switzer. These grain boundaries can greatly limit the performance of an electronic device.

“Say you’re making a solar cell or an LED,” he says. “In a semiconductor, you have electrons and you have holes, which are the opposite of electrons. They can combine at grain boundaries and give off heat. And then you end up losing the light that you get out of an LED, or the current or voltage that you might get out of a solar cell.”

Most electronics on the market are made of silicon because it’s “relatively cheap, but also highly ordered,” Switzer says.

“99.99 percent of electronics are made out of silicon, and there’s a reason – it works great,” he says. “It’s a single crystal, and the atoms are perfectly aligned. But, when you have a single crystal like that, typically, it’s not flexible.”

By starting with single crystal silicon and growing gold foils on it, Switzer is able to keep the high order of silicon on the foil. But because the foil is gold, it’s also highly durable and flexible.

“We bent it 4,000 times, and basically the resistance didn’t change,” he says.

The gold foils are also essentially transparent because they are so thin. According to Switzer, his team has peeled foils as thin as seven nanometers.

Switzer says the challenge his research team faced was not in growing gold on the single crystal silicon, but getting it to peel off as such a thin layer of foil. Gold typically bonds very well to silicon.

“So we came up with this trick where we could photo-electrochemically oxidize the silicon,” Switzer says. “And the gold just slides off.”

Photoelectrochemical oxidation is the process by which light enables a semiconductor material, in this case silicon, to promote a catalytic oxidation reaction.

Switzer says thousands of gold foils—or foils of any number of other metals—can be made from a single crystal wafer of silicon.

The research team’s discovery can be considered a “happy accident.” Switzer says they were looking for a cheap way to make single crystals when they discovered this process.

“This is something that I think a lot of people who are interested in working with highly ordered materials like single crystals would appreciate making really easily,” he says. “Besides making flexible devices, it’s just going to open up a field for anybody who wants to work with single crystals.”

Learn more: Research leads to a golden discovery for wearable technology