Category Archives: electronics

Training drugs

This summarizes some of what’s happening in nanomedicine and provides a plug (boost) for the  University of Cambridge’s nanotechnology programmes (from a June 26, 2017 news item on Nanowerk),

Nanotechnology is creating new opportunities for fighting disease – from delivering drugs in smart packaging to nanobots powered by the world’s tiniest engines.

Chemotherapy benefits a great many patients but the side effects can be brutal.
When a patient is injected with an anti-cancer drug, the idea is that the molecules will seek out and destroy rogue tumour cells. However, relatively large amounts need to be administered to reach the target in high enough concentrations to be effective. As a result of this high drug concentration, healthy cells may be killed as well as cancer cells, leaving many patients weak, nauseated and vulnerable to infection.

One way that researchers are attempting to improve the safety and efficacy of drugs is to use a relatively new area of research known as nanothrapeutics to target drug delivery just to the cells that need it.

Professor Sir Mark Welland is Head of the Electrical Engineering Division at Cambridge. In recent years, his research has focused on nanotherapeutics, working in collaboration with clinicians and industry to develop better, safer drugs. He and his colleagues don’t design new drugs; instead, they design and build smart packaging for existing drugs.

The University of Cambridge has produced a video interview (referencing a 1966 movie ‘Fantastic Voyage‘ in its title)  with Sir Mark Welland,

A June 23, 2017 University of Cambridge press release, which originated the news item, delves further into the topic of nanotherapeutics (nanomedicine) and nanomachines,

Nanotherapeutics come in many different configurations, but the easiest way to think about them is as small, benign particles filled with a drug. They can be injected in the same way as a normal drug, and are carried through the bloodstream to the target organ, tissue or cell. At this point, a change in the local environment, such as pH, or the use of light or ultrasound, causes the nanoparticles to release their cargo.

Nano-sized tools are increasingly being looked at for diagnosis, drug delivery and therapy. “There are a huge number of possibilities right now, and probably more to come, which is why there’s been so much interest,” says Welland. Using clever chemistry and engineering at the nanoscale, drugs can be ‘taught’ to behave like a Trojan horse, or to hold their fire until just the right moment, or to recognise the target they’re looking for.

“We always try to use techniques that can be scaled up – we avoid using expensive chemistries or expensive equipment, and we’ve been reasonably successful in that,” he adds. “By keeping costs down and using scalable techniques, we’ve got a far better chance of making a successful treatment for patients.”

In 2014, he and collaborators demonstrated that gold nanoparticles could be used to ‘smuggle’ chemotherapy drugs into cancer cells in glioblastoma multiforme, the most common and aggressive type of brain cancer in adults, which is notoriously difficult to treat. The team engineered nanostructures containing gold and cisplatin, a conventional chemotherapy drug. A coating on the particles made them attracted to tumour cells from glioblastoma patients, so that the nanostructures bound and were absorbed into the cancer cells.

Once inside, these nanostructures were exposed to radiotherapy. This caused the gold to release electrons that damaged the cancer cell’s DNA and its overall structure, enhancing the impact of the chemotherapy drug. The process was so effective that 20 days later, the cell culture showed no evidence of any revival, suggesting that the tumour cells had been destroyed.

While the technique is still several years away from use in humans, tests have begun in mice. Welland’s group is working with MedImmune, the biologics R&D arm of pharmaceutical company AstraZeneca, to study the stability of drugs and to design ways to deliver them more effectively using nanotechnology.

“One of the great advantages of working with MedImmune is they understand precisely what the requirements are for a drug to be approved. We would shut down lines of research where we thought it was never going to get to the point of approval by the regulators,” says Welland. “It’s important to be pragmatic about it so that only the approaches with the best chance of working in patients are taken forward.”

The researchers are also targeting diseases like tuberculosis (TB). With funding from the Rosetrees Trust, Welland and postdoctoral researcher Dr Íris da luz Batalha are working with Professor Andres Floto in the Department of Medicine to improve the efficacy of TB drugs.

Their solution has been to design and develop nontoxic, biodegradable polymers that can be ‘fused’ with TB drug molecules. As polymer molecules have a long, chain-like shape, drugs can be attached along the length of the polymer backbone, meaning that very large amounts of the drug can be loaded onto each polymer molecule. The polymers are stable in the bloodstream and release the drugs they carry when they reach the target cell. Inside the cell, the pH drops, which causes the polymer to release the drug.

In fact, the polymers worked so well for TB drugs that another of Welland’s postdoctoral researchers, Dr Myriam Ouberaï, has formed a start-up company, Spirea, which is raising funding to develop the polymers for use with oncology drugs. Ouberaï is hoping to establish a collaboration with a pharma company in the next two years.

“Designing these particles, loading them with drugs and making them clever so that they release their cargo in a controlled and precise way: it’s quite a technical challenge,” adds Welland. “The main reason I’m interested in the challenge is I want to see something working in the clinic – I want to see something working in patients.”

Could nanotechnology move beyond therapeutics to a time when nanomachines keep us healthy by patrolling, monitoring and repairing the body?

Nanomachines have long been a dream of scientists and public alike. But working out how to make them move has meant they’ve remained in the realm of science fiction.

But last year, Professor Jeremy Baumberg and colleagues in Cambridge and the University of Bath developed the world’s tiniest engine – just a few billionths of a metre [nanometre] in size. It’s biocompatible, cost-effective to manufacture, fast to respond and energy efficient.

The forces exerted by these ‘ANTs’ (for ‘actuating nano-transducers’) are nearly a hundred times larger than those for any known device, motor or muscle. To make them, tiny charged particles of gold, bound together with a temperature-responsive polymer gel, are heated with a laser. As the polymer coatings expel water from the gel and collapse, a large amount of elastic energy is stored in a fraction of a second. On cooling, the particles spring apart and release energy.

The researchers hope to use this ability of ANTs to produce very large forces relative to their weight to develop three-dimensional machines that swim, have pumps that take on fluid to sense the environment and are small enough to move around our bloodstream.

Working with Cambridge Enterprise, the University’s commercialisation arm, the team in Cambridge’s Nanophotonics Centre hopes to commercialise the technology for microfluidics bio-applications. The work is funded by the Engineering and Physical Sciences Research Council and the European Research Council.

“There’s a revolution happening in personalised healthcare, and for that we need sensors not just on the outside but on the inside,” explains Baumberg, who leads an interdisciplinary Strategic Research Network and Doctoral Training Centre focused on nanoscience and nanotechnology.

“Nanoscience is driving this. We are now building technology that allows us to even imagine these futures.”

I have featured Welland and his work here before and noted his penchant for wanting to insert nanodevices into humans as per this excerpt from an April 30, 2010 posting,
Getting back to the Cambridge University video, do go and watch it on the Nanowerk site. It is fun and very informative and approximately 17 mins. I noticed that they reused part of their Nokia morph animation (last mentioned on this blog here) and offered some thoughts from Professor Mark Welland, the team leader on that project. Interestingly, Welland was talking about yet another possibility. (Sometimes I think nano goes too far!) He was suggesting that we could have chips/devices in our brains that would allow us to think about phoning someone and an immediate connection would be made to that person. Bluntly—no. Just think what would happen if the marketers got access and I don’t even want to think what a person who suffers psychotic breaks (i.e., hearing voices) would do with even more input. Welland starts to talk at the 11 minute mark (I think). For an alternative take on the video and more details, visit Dexter Johnson’s blog, Nanoclast, for this posting. Hint, he likes the idea of a phone in the brain much better than I do.

I’m not sure what could have occasioned this latest press release and related video featuring Welland and nanotherapeutics other than guessing that it was a slow news period.

IBM and a 5 nanometre chip

If this continues, they’re going to have change the scale from nano to pico. IBM has announced work on a 5 nanometre (5nm) chip in a June 5, 2017 news item on Nanotechnology Now,

IBM (NYSE: IBM), its Research Alliance partners GLOBALFOUNDRIES and Samsung, and equipment suppliers have developed an industry-first process to build silicon nanosheet transistors that will enable 5 nanometer (nm) chips. The details of the process will be presented at the 2017 Symposia on VLSI Technology and Circuits conference in Kyoto, Japan. In less than two years since developing a 7nm test node chip with 20 billion transistors, scientists have paved the way for 30 billion switches on a fingernail-sized chip.

A June 5, 2017 IBM news release, which originated the news item, spells out some of the details about IBM’s latest breakthrough,

The resulting increase in performance will help accelerate cognitive computing [emphasis mine], the Internet of Things (IoT), and other data-intensive applications delivered in the cloud. The power savings could also mean that the batteries in smartphones and other mobile products could last two to three times longer than today’s devices, before needing to be charged.

Scientists working as part of the IBM-led Research Alliance at the SUNY Polytechnic Institute Colleges of Nanoscale Science and Engineering’s NanoTech Complex in Albany, NY achieved the breakthrough by using stacks of silicon nanosheets as the device structure of the transistor, instead of the standard FinFET architecture, which is the blueprint for the semiconductor industry up through 7nm node technology.

“For business and society to meet the demands of cognitive and cloud computing in the coming years, advancement in semiconductor technology is essential,” said Arvind Krishna, senior vice president, Hybrid Cloud, and director, IBM Research. “That’s why IBM aggressively pursues new and different architectures and materials that push the limits of this industry, and brings them to market in technologies like mainframes and our cognitive systems.”

The silicon nanosheet transistor demonstration, as detailed in the Research Alliance paper Stacked Nanosheet Gate-All-Around Transistor to Enable Scaling Beyond FinFET, and published by VLSI, proves that 5nm chips are possible, more powerful, and not too far off in the future.

Compared to the leading edge 10nm technology available in the market, a nanosheet-based 5nm technology can deliver 40 percent performance enhancement at fixed power, or 75 percent power savings at matched performance. This improvement enables a significant boost to meeting the future demands of artificial intelligence (AI) systems, virtual reality and mobile devices.

Building a New Switch

“This announcement is the latest example of the world-class research that continues to emerge from our groundbreaking public-private partnership in New York,” said Gary Patton, CTO and Head of Worldwide R&D at GLOBALFOUNDRIES. “As we make progress toward commercializing 7nm in 2018 at our Fab 8 manufacturing facility, we are actively pursuing next-generation technologies at 5nm and beyond to maintain technology leadership and enable our customers to produce a smaller, faster, and more cost efficient generation of semiconductors.”

IBM Research has explored nanosheet semiconductor technology for more than 10 years. This work is the first in the industry to demonstrate the feasibility to design and fabricate stacked nanosheet devices with electrical properties superior to FinFET architecture.

This same Extreme Ultraviolet (EUV) lithography approach used to produce the 7nm test node and its 20 billion transistors was applied to the nanosheet transistor architecture. Using EUV lithography, the width of the nanosheets can be adjusted continuously, all within a single manufacturing process or chip design. This adjustability permits the fine-tuning of performance and power for specific circuits – something not possible with today’s FinFET transistor architecture production, which is limited by its current-carrying fin height. Therefore, while FinFET chips can scale to 5nm, simply reducing the amount of space between fins does not provide increased current flow for additional performance.

“Today’s announcement continues the public-private model collaboration with IBM that is energizing SUNY-Polytechnic’s, Albany’s, and New York State’s leadership and innovation in developing next generation technologies,” said Dr. Bahgat Sammakia, Interim President, SUNY Polytechnic Institute. “We believe that enabling the first 5nm transistor is a significant milestone for the entire semiconductor industry as we continue to push beyond the limitations of our current capabilities. SUNY Poly’s partnership with IBM and Empire State Development is a perfect example of how Industry, Government and Academia can successfully collaborate and have a broad and positive impact on society.”

Part of IBM’s $3 billion, five-year investment in chip R&D (announced in 2014), the proof of nanosheet architecture scaling to a 5nm node continues IBM’s legacy of historic contributions to silicon and semiconductor innovation. They include the invention or first implementation of the single cell DRAM, the Dennard Scaling Laws, chemically amplified photoresists, copper interconnect wiring, Silicon on Insulator, strained engineering, multi core microprocessors, immersion lithography, high speed SiGe, High-k gate dielectrics, embedded DRAM, 3D chip stacking and Air gap insulators.

I last wrote about IBM and computer chips in a July 15, 2015 posting regarding their 7nm chip. You may want to scroll down approximately 55% of the way where I note research from MIT (Massachusetts Institute of Technology) about metal nanoparticles with unexpected properties possibly having an impact on nanoelectronics.

Getting back to IBM, they have produced a slick video about their 5nm chip breakthrough,

Meanwhile, Katherine Bourzac provides technical detail in a June 5, 2017 posting on the Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website), Note: A link has been removed,

Researchers at IBM believe the future of the transistor is in stacked nanosheets. …

Today’s state-of-the-art transistor is the finFET, named for the fin-like ridges of current-carrying silicon that project from the chip’s surface. The silicon fins are surrounded on their three exposed sides by a structure called the gate. The gate switches the flow of current on, and prevents electrons from leaking out when the transistor is off. This design is expected to last from this year’s bleeding-edge process technology, the “10-nanometer” node, through the next node, 7 nanometers. But any smaller, and these transistors will become difficult to switch off: electrons will leak out, even with the three-sided gates.

So the semiconductor industry has been working on alternatives for the upcoming 5 nanometer node. One popular idea is to use lateral silicon nanowires that are completely surrounded by the gate, preventing electron leaks and saving power. This design is called “gate all around.” IBM’s new design is a variation on this. In their test chips, each transistor is made up of three stacked horizontal sheets of silicon, each only a few nanometers thick and completely surrounded by a gate.

Why a sheet instead of a wire? Huiming Bu, director of silicon integration and devices at IBM, says nanosheets can bring back one of the benefits of pre-finFET, planar designs. Designers used to be able to vary the width of a transistor to prioritize fast operations or energy efficiency. Varying the amount of silicon in a finFET transistor is not practicable because it would mean making some fins taller and other shorter. Fins must all be the same height due to manufacturing constraints, says Bu.

IBM’s nanosheets can range from 8 to 50 nanometers in width. “Wider gives you better performance but takes more power, smaller width relaxes performance but reduces power use,” says Bu. This will allow circuit designers to pick and choose what they need, whether they are making a power efficient mobile chip processor or designing a bank of SRAM memory. “We are bringing flexibility back to the designers,” he says.

The test chips have 30 billion transistors. …

It was a struggle trying to edit Bourzac’s posting with its good detail and clear writing. I encourage you to read it (June 5, 2017 posting) in its entirety.

As for where this drive downwards to the ‘ever smaller’ is going, there’s Dexter’s Johnson’s June 29, 2017 posting about another IBM team’s research on his Nanoclast blog on the IEEE website (Note: Links have been removed),

There have been increasing signs coming from the research community that carbon nanotubes are beginning to step up to the challenge of offering a real alternative to silicon-based complementary metal-oxide semiconductor (CMOS) transistors.

Now, researchers at IBM Thomas J. Watson Research Center have advanced carbon nanotube-based transistors another step toward meeting the demands of the International Technology Roadmap for Semiconductors (ITRS) for the next decade. The IBM researchers have fabricated a p-channel transistor based on carbon nanotubes that takes up less than half the space of leading silicon technologies while operating at a lower voltage.

In research described in the journal Science, the IBM scientists used a carbon nanotube p-channel to reduce the transistor footprint; their transistor contains all components to 40 square nanometers [emphasis mine], an ITRS roadmap benchmark for ten years out.

One of the keys to being able to reduce the transistor to such a small size is the use of the carbon nanotube as the channel in place of silicon. The nanotube is only 1 nanometer thick. Such thinness offers a significant advantage in electrostatics, so that it’s possible to reduce the device gate length to 10 nanometers without seeing the device performance adversely affected by short-channel effects. An additional benefit of the nanotubes is that the electrons travel much faster, which contributes to a higher level of device performance.

Happy reading!

Ora Sound, a Montréal-based startup, and its ‘graphene’ headphones

For all the excitement about graphene there aren’t that many products as Glenn Zorpette notes in a June 20, 2017 posting about Ora Sound and its headphones on the Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website; Note: Links have been removed),

Graphene has long been touted as a miracle material that would deliver everything from tiny, ultralow-power transistors to the vastly long and ultrastrong cable [PDF] needed for a space elevator. And yet, 13 years of graphene development, and R&D expenditures well in the tens of billions of dollars have so far yielded just a handful of niche products. The most notable by far is a line of tennis racquets in which relatively small amounts of graphene are used to stiffen parts of the frame.

Ora Sound, a Montreal-based [Québec, Canada] startup, hopes to change all that. On 20 June [2017], it unveiled a Kickstarter campaign for a new audiophile-grade headphone that uses cones, also known as membranes, made of a form of graphene. “To the best of our knowledge, we are the first company to find a significant, commercially viable application for graphene,” says Ora cofounder Ari Pinkas, noting that the cones in the headphones are 95 percent graphene.

Kickstarter

It should be noted that participating in a Kickstarter campaign is an investment/gamble. I am not endorsing Ora Sound or its products. That said, this does look interesting (from the ORA: The World’s First Graphene Headphones Kickstarter campaign webpage),

ORA GQ Headphones uses nanotechnology to deliver the most groundbreaking audio listening experience. Scientists have long promised that one day Graphene will find its way into many facets of our lives including displays, electronic circuits and sensors. ORA’s Graphene technology makes it one of the first companies to have created a commercially viable application for this Nobel-prize winning material, a major scientific achievement.

The GQ Headphones come equipped with ORA’s patented GrapheneQ™ membranes, providing unparalleled fidelity. The headphones also offer all the features you would expect from a high-end audio product: wired/wireless operation, a gesture control track-pad, a digital MEMS microphone, breathable lambskin leather and an ear-shaped design optimized for sound quality and isolated comfort.

They have produced a slick video to promote their campaign,

At the time of publishing this post, the campaign will run for another eight days and has raised $650,949 CAD. This is more than $500,000 dollars over the company’s original goal of $135,000. I’m sure they’re ecstatic but this success can be a mixed blessing. They have many more people expecting a set of headphones than they anticipated and that can mean production issues.

Further, there appears to be only one member of the team with business experience and his (Ari Pinkas) experience includes marketing strategy for a few years and then founding an online marketplace for teachers. I would imagine Pinkas will be experiencing a very steep learning curve. Hopefully, Helge Seetzen, a member of the company’s advisory board will be able to offer assistance. According to Seetzen’s Wikipedia entry, he is a “… German technologist and businessman known for imaging & multimedia research and commercialization,” as well as, having a Canadian educational background and business experience. The rest of the team and advisory board appear to be academics.

The technology

A March 14, 2017 article by Andy Riga for the Montréal Gazette gives a general description of the technology,

A Montreal startup is counting on technology sparked by a casual conversation between two brothers pursuing PhDs at McGill University.

They were chatting about their disparate research areas — one, in engineering, was working on using graphene, a form of carbon, in batteries; the other, in music, was looking at the impact of electronics on the perception of audio quality.

At first glance, the invention that ensued sounds humdrum.

It’s a replacement for an item you use every day. It’s paper thin, you probably don’t realize it’s there and its design has not changed much in more than a century. Called a membrane or diaphragm, it’s the part of a loudspeaker that vibrates to create the sound from the headphones over your ears, the wireless speaker on your desk, the cellphone in your hand.

Membranes are normally made of paper, Mylar or aluminum.

Ora’s innovation uses graphene, a remarkable material whose discovery garnered two scientists the 2010 Nobel Prize in physics but which has yet to fulfill its promise.

“Because it’s so stiff, our membrane gets better sound quality,” said Robert-Eric Gaskell, who obtained his PhD in sound recording in 2015. “It can produce more sound with less distortion, and the sound that you hear is more true to the original sound intended by the artist.

“And because it’s so light, we get better efficiency — the lighter it is, the less energy it takes.”

In January, the company demonstrated its membrane in headphones at the Consumer Electronics Show, a big trade convention in Las Vegas.

Six cellphone manufacturers expressed interest in Ora’s technology, some of which are now trying prototypes, said Ari Pinkas, in charge of product marketing at Ora. “We’re talking about big cellphone manufacturers — big, recognizable names,” he said.

Technology companies are intrigued by the idea of using Ora’s technology to make smaller speakers so they can squeeze other things, such as bigger batteries, into the limited space in electronic devices, Pinkas said. Others might want to use Ora’s membrane to allow their devices to play music louder, he added.

Makers of regular speakers, hearing aids and virtual-reality headsets have also expressed interest, Pinkas said.

Ora is still working on headphones.

Riga’s article offers a good overview for people who are not familiar with graphene.

Zorpette’s June 20, 2017 posting (on Nanoclast) offers a few more technical details (Note: Links have been removed),

During an interview and demonstration in the IEEE Spectrum offices, Pinkas and Robert-Eric Gaskell, another of the company’s cofounders, explained graphene’s allure to audiophiles. “Graphene has the ideal properties for a membrane,” Gaskell says. “It’s incredibly stiff, very lightweight—a rare combination—and it’s well damped,” which means it tends to quell spurious vibrations. By those metrics, graphene soundly beats all the usual choices: mylar, paper, aluminum, or even beryllium, Gaskell adds.

The problem is making it in sheets large enough to fashion into cones. So-called “pristine” graphene exists as flakes, [emphasis mine] perhaps 10 micrometers across, and a single atom thick. To make larger, strong sheets of graphene, researchers attach oxygen atoms to the flakes, and then other elements to the oxygen atoms to cross-link the flakes and hold them together strongly in what materials scientists call a laminate structure. The intellectual property behind Ora’s advance came from figuring out how to make these structures suitably thick and in the proper shape to function as speaker cones, Gaskell says. In short, he explains, the breakthrough was, “being able to manufacture” in large numbers, “and in any geometery we want.”

Much of the R&D work that led to Ora’s process was done at nearby McGill University, by professor Thomas Szkopek of the Electrical and Computer Engineering department. Szkopek worked with Peter Gaskell, Robert-Eric’s younger brother. Ora is also making use of patents that arose from work done on graphene by the Nguyen Group at Northwestern University, in Evanston, Ill.

Robert-Eric Gaskell and Pinkas arrived at Spectrum with a preproduction model of their headphones, as well as some other headphones for the sake of comparison. The Ora prototype is clearly superior to the comparison models, but that’s not much of a surprise. …

… In the 20 minutes or so I had to audition Ora’s preproduction model, I listened to an assortment of classical and jazz standards and I came away impressed. The sound is precise, with fine details sharply rendered. To my surprise, I was reminded of planar-magnetic type headphones that are now surging in popularity in the upper reaches of the audiophile headphone market. Bass is smooth and tight. Overall, the unit holds up quite well against closed-back models in the $400 to $500 range I’ve listened to from Grado, Bowers & Wilkins, and Audeze.

Ora’s Kickstarter campaign page (Graphene vs GrapheneQ subsection) offers some information about their unique graphene composite,

A TECHNICAL INTRODUCTION TO GRAPHENE

Graphene is a new material, first isolated only 13 years ago. Formed from a single layer of carbon atoms, Graphene is a hexagonal crystal lattice in a perfect honeycomb structure. This fundamental geometry makes Graphene ridiculously strong and lightweight. In its pure form, Graphene is a single atomic layer of carbon. It can be very expensive and difficult to produce in sizes any bigger than small flakes. These challenges have prevented pristine Graphene from being integrated into consumer technologies.

THE GRAPHENEQ™ SOLUTION

At ORA, we’ve spent the last few years creating GrapheneQ, our own, proprietary Graphene-based nanocomposite formulation. We’ve specifically designed and optimized it for use in acoustic transducers. GrapheneQ is a composite material which is over 95% Graphene by weight. It is formed by depositing flakes of Graphene into thousands of layers that are bonded together with proprietary cross-linking agents. Rather than trying to form one, continuous layer of Graphene, GrapheneQ stacks flakes of Graphene together into a laminate material that preserves the benefits of Graphene while allowing the material to be formed into loudspeaker cones.

Scanning Electron Microscope (SEM) Comparison
Scanning Electron Microscope (SEM) Comparison

If you’re interested in more technical information on sound, acoustics, soundspeakers, and Ora’s graphene-based headphones, it’s all there on Ora’s Kickstarter campaign page.

The Québec nanotechnology scene in context and graphite flakes for graphene

There are two Canadian provinces that are heavily invested in nanotechnology research and commercialization efforts. The province of Québec has poured money into their nanotechnology efforts, while the province of Alberta has also invested heavily in nanotechnology, it has also managed to snare additional federal funds to host Canada’s National Institute of Nanotechnology (NINT). (This appears to be a current NINT website or you can try this one on the National Research Council website). I’d rank Ontario as being a third centre with the other provinces being considerably less invested. As for the North, I’ve not come across any nanotechnology research from that region. Finally, as I stumble more material about nanotechnology in Québec than I do for any other province, that’s the reason I rate Québec as the most successful in its efforts.

Regarding graphene, Canada seems to have an advantage. We have great graphite flakes for making graphene. With mines in at least two provinces, Ontario and Québec, we have a ready source of supply. In my first posting (July 25, 2011) about graphite mines here, I had this,

Who knew large flakes could be this exciting? From the July 25, 2011 news item on Nanowerk,

Northern Graphite Corporation has announced that graphene has been successfully made on a test basis using large flake graphite from the Company’s Bissett Creek project in Northern Ontario. Northern’s standard 95%C, large flake graphite was evaluated as a source material for making graphene by an eminent professor in the field at the Chinese Academy of Sciences who is doing research making graphene sheets larger than 30cm2 in size using the graphene oxide methodology. The tests indicated that graphene made from Northern’s jumbo flake is superior to Chinese powder and large flake graphite in terms of size, higher electrical conductivity, lower resistance and greater transparency.

Approximately 70% of production from the Bissett Creek property will be large flake (+80 mesh) and almost all of this will in fact be +48 mesh jumbo flake which is expected to attract premium pricing and be a better source material for the potential manufacture of graphene. The very high percentage of large flakes makes Bissett Creek unique compared to most graphite deposits worldwide which produce a blend of large, medium and small flakes, as well as a large percentage of low value -150 mesh flake and amorphous powder which are not suitable for graphene, Li ion batteries or other high end, high growth applications.

Since then I’ve stumbled across more information about Québec’s mines than Ontario’s  as can be seen:

There are some other mentions of graphite mines in other postings but they are tangential to what’s being featured:

  • (my Oct. 26, 2015 posting about St. Jean Carbon and its superconducting graphene and
  • my Feb. 20, 2015 posting about Nanoxplore and graphene production in Québec; and
  • this Feb. 23, 2015 posting about Grafoid and its sister company, Focus Graphite which gets its graphite flakes from a deposit in the northeastern part of Québec).

 

After reviewing these posts, I’ve begun to wonder where Ora’s graphite flakes come from? In any event, I wish the folks at Ora and their Kickstarter funders the best of luck.

IBM to build brain-inspired AI supercomputing system equal to 64 million neurons for US Air Force

This is the second IBM computer announcement I’ve stumbled onto within the last 4 weeks or so,  which seems like a veritable deluge given the last time I wrote about IBM’s computing efforts was in an Oct. 8, 2015 posting about carbon nanotubes,. I believe that up until now that was my  most recent posting about IBM and computers.

Moving onto the news, here’s more from a June 23, 3017 news item on Nanotechnology Now,

IBM (NYSE: IBM) and the U.S. Air Force Research Laboratory (AFRL) today [June 23, 2017] announced they are collaborating on a first-of-a-kind brain-inspired supercomputing system powered by a 64-chip array of the IBM TrueNorth Neurosynaptic System. The scalable platform IBM is building for AFRL will feature an end-to-end software ecosystem designed to enable deep neural-network learning and information discovery. The system’s advanced pattern recognition and sensory processing power will be the equivalent of 64 million neurons and 16 billion synapses, while the processor component will consume the energy equivalent of a dim light bulb – a mere 10 watts to power.

A June 23, 2017 IBM news release, which originated the news item, describes the proposed collaboration, which is based on IBM’s TrueNorth brain-inspired chip architecture (see my Aug. 8, 2014 posting for more about TrueNorth),

IBM researchers believe the brain-inspired, neural network design of TrueNorth will be far more efficient for pattern recognition and integrated sensory processing than systems powered by conventional chips. AFRL is investigating applications of the system in embedded, mobile, autonomous settings where, today, size, weight and power (SWaP) are key limiting factors.

The IBM TrueNorth Neurosynaptic System can efficiently convert data (such as images, video, audio and text) from multiple, distributed sensors into symbols in real time. AFRL will combine this “right-brain” perception capability of the system with the “left-brain” symbol processing capabilities of conventional computer systems. The large scale of the system will enable both “data parallelism” where multiple data sources can be run in parallel against the same neural network and “model parallelism” where independent neural networks form an ensemble that can be run in parallel on the same data.

“AFRL was the earliest adopter of TrueNorth for converting data into decisions,” said Daniel S. Goddard, director, information directorate, U.S. Air Force Research Lab. “The new neurosynaptic system will be used to enable new computing capabilities important to AFRL’s mission to explore, prototype and demonstrate high-impact, game-changing technologies that enable the Air Force and the nation to maintain its superior technical advantage.”

“The evolution of the IBM TrueNorth Neurosynaptic System is a solid proof point in our quest to lead the industry in AI hardware innovation,” said Dharmendra S. Modha, IBM Fellow, chief scientist, brain-inspired computing, IBM Research – Almaden. “Over the last six years, IBM has expanded the number of neurons per system from 256 to more than 64 million – an 800 percent annual increase over six years.’’

The system fits in a 4U-high (7”) space in a standard server rack and eight such systems will enable the unprecedented scale of 512 million neurons per rack. A single processor in the system consists of 5.4 billion transistors organized into 4,096 neural cores creating an array of 1 million digital neurons that communicate with one another via 256 million electrical synapses.    For CIFAR-100 dataset, TrueNorth achieves near state-of-the-art accuracy, while running at >1,500 frames/s and using 200 mW (effectively >7,000 frames/s per Watt) – orders of magnitude lower speed and energy than a conventional computer running inference on the same neural network.

The IBM TrueNorth Neurosynaptic System was originally developed under the auspices of Defense Advanced Research Projects Agency’s (DARPA) Systems of Neuromorphic Adaptive Plastic Scalable Electronics (SyNAPSE) program in collaboration with Cornell University. In 2016, the TrueNorth Team received the inaugural Misha Mahowald Prize for Neuromorphic Engineering and TrueNorth was accepted into the Computer History Museum.  Research with TrueNorth is currently being performed by more than 40 universities, government labs, and industrial partners on five continents.

There is an IBM video accompanying this news release, which seems more promotional than informational,

The IBM scientist featured in the video has a Dec. 19, 2016 posting on an IBM research blog which provides context for this collaboration with AFRL,

2016 was a big year for brain-inspired computing. My team and I proved in our paper “Convolutional networks for fast, energy-efficient neuromorphic computing” that the value of this breakthrough is that it can perform neural network inference at unprecedented ultra-low energy consumption. Simply stated, our TrueNorth chip’s non-von Neumann architecture mimics the brain’s neural architecture — giving it unprecedented efficiency and scalability over today’s computers.

The brain-inspired TrueNorth processor [is] a 70mW reconfigurable silicon chip with 1 million neurons, 256 million synapses, and 4096 parallel and distributed neural cores. For systems, we present a scale-out system loosely coupling 16 single-chip boards and a scale-up system tightly integrating 16 chips in a 4´4 configuration by exploiting TrueNorth’s native tiling.

For the scale-up systems we summarize our approach to physical placement of neural network, to reduce intra- and inter-chip network traffic. The ecosystem is in use at over 30 universities and government / corporate labs. Our platform is a substrate for a spectrum of applications from mobile and embedded computing to cloud and supercomputers.
TrueNorth Ecosystem for Brain-Inspired Computing: Scalable Systems, Software, and Applications

TrueNorth, once loaded with a neural network model, can be used in real-time as a sensory streaming inference engine, performing rapid and accurate classifications while using minimal energy. TrueNorth’s 1 million neurons consume only 70 mW, which is like having a neurosynaptic supercomputer the size of a postage stamp that can run on a smartphone battery for a week.

Recently, in collaboration with Lawrence Livermore National Laboratory, U.S. Air Force Research Laboratory, and U.S. Army Research Laboratory, we published our fifth paper at IEEE’s prestigious Supercomputing 2016 conference that summarizes the results of the team’s 12.5-year journey (see the associated graphic) to unlock this value proposition. [keep scrolling for the graphic]

Applying the mind of a chip

Three of our partners, U.S. Army Research Lab, U.S. Air Force Research Lab and Lawrence Livermore National Lab, contributed sections to the Supercomputing paper each showcasing a different TrueNorth system, as summarized by my colleagues Jun Sawada, Brian Taba, Pallab Datta, and Ben Shaw:

U.S. Army Research Lab (ARL) prototyped a computational offloading scheme to illustrate how TrueNorth’s low power profile enables computation at the point of data collection. Using the single-chip NS1e board and an Android tablet, ARL researchers created a demonstration system that allows visitors to their lab to hand write arithmetic expressions on the tablet, with handwriting streamed to the NS1e for character recognition, and recognized characters sent back to the tablet for arithmetic calculation.

Of course, the point here is not to make a handwriting calculator, it is to show how TrueNorth’s low power and real time pattern recognition might be deployed at the point of data collection to reduce latency, complexity and transmission bandwidth, as well as back-end data storage requirements in distributed systems.

U.S. Air Force Research Lab (AFRL) contributed another prototype application utilizing a TrueNorth scale-out system to perform a data-parallel text extraction and recognition task. In this application, an image of a document is segmented into individual characters that are streamed to AFRL’s NS1e16 TrueNorth system for parallel character recognition. Classification results are then sent to an inference-based natural language model to reconstruct words and sentences. This system can process 16,000 characters per second! AFRL plans to implement the word and sentence inference algorithms on TrueNorth, as well.

Lawrence Livermore National Lab (LLNL) has a 16-chip NS16e scale-up system to explore the potential of post-von Neumann computation through larger neural models and more complex algorithms, enabled by the native tiling characteristics of the TrueNorth chip. For the Supercomputing paper, they contributed a single-chip application performing in-situ process monitoring in an additive manufacturing process. LLNL trained a TrueNorth network to recognize seven classes related to track weld quality in welds produced by a selective laser melting machine. Real-time weld quality determination allows for closed-loop process improvement and immediate rejection of defective parts. This is one of several applications LLNL is developing to showcase TrueNorth as a scalable platform for low-power, real-time inference.

[downloaded from https://www.ibm.com/blogs/research/2016/12/the-brains-architecture-efficiency-on-a-chip/] Courtesy: IBM

I gather this 2017 announcement is the latest milestone on the TrueNorth journey.

Canada: Happy 150th anniversary!

There’s a bit of fun in the title for Jennifer Pascoe’s June 27, 2017 University of Alberta news release, (assuming you’re familiar with the opening words for Canada’s national anthem: “O Canada!”),

Nan-Oh-Canada

At just 32 atoms and visible only through a million-dollar scanning tunneling microscope, a tiny maple leaf created by UAlberta PhD student Roshan Achal illustrates the next wave of green technology, all while showing patriotic pride.

Invisible to the naked eye, the little leaf is pulling triple duty: celebrating Canada’s 150th birthday, attempting a world record, and—with critical implications for our technology-driven information society—providing critical steps towards the next generation of smaller and faster computers.

“It’s super cool and super Canadian and demonstrates our strength and skill in this niche of nanotechnology,” said Achal. “Almost no one else in the world can do it this well.”

Unlike other ultra-small atomic creations, this maple leaf retains its structure at room temperature.

A tiny act of patriotism

At ten nanometres in width, the leaf is roughly 100 times smaller than the world’s smallest national flag—created at the University of Waterloo in September 2016—10,000 times smaller than a human hair, and 53 million times smaller than the world’s largest maple leaf.

The leaf demonstrates the technique of building structures atom by atom (via something called scanning tunneling microscopy), which is being used to create and study circuitry to make smaller computational components while simultaneously speeding them up. In this particular niche of nanotechnology, Canada rates high on the international stage, with the University of Alberta leading the way.

“It’s hard to imagine, because it’s so small, but picture a surface almost like bubble wrap,” explained Achal of the silicon crystal wafer on which the leaf is patterned. “The bubbles are actually hydrogen atoms bonded to the surface, and we are able to pop those bubbles to create patterns.”

Nano pioneers

Achal is working on perfecting that patterning process to make atomic structures which will help revolutionize the next generation of computing by consuming less power. He’s using an ultra-sharp tool, a tip just one atom in width, which was perfected by his supervisor, UAlberta physics professor Robert Wolkow, whom Achal calls a “visionary.”

A pioneer in scanning tunneling microscopy technology, Wolkow already has a Guinness World Record for the nano-tip, the world’s sharpest man-made object, which provides unparalleled precision for patterning electronic circuits.

Achal explained the team wanted to do something to demonstrate their technological capabilities, but also something fun and meaningful to mark the occasion of Canada 150.

While they wait to hear back from Guinness World Records with an official nod to their small sculpture, the scientists continue to perfect their technique, with significant implications for next generation computing. This capability is now being put to commercial use by local spin-off Quantum Silicon Incorporated to make revolutionary ultra-fast and efficient silicon electronic devices.

It’s nice to see the enthusiasm although calling Wolkow ‘a visionary’ seems a little over the top especially with all of the other exuberance (super Canadian?). In any event, there are very few visionaries, maybe Wolkow could have been described as amazing, groundbreaking, and/or extraordinary?

Getting back to the point: Happy 150th Canada Day July 1, 2017!

h/t June 27, 2017 news item on Nanowerk.

Scientists claim off-the-shelf, power-generating clothes almost here

PEDOT-coated yarns act as “normal” wires to transmit electricity from a wall outlet to an incandescent lightbulb. Materials scientist Trisha Andrew at UMass Amherst and colleagues outline in a new paper how they have invented a way to apply breathable, pliable, metal-free electrodes to fabric and off-the-shelf clothing so it feels good to the touch and also transports electricity to power small electronics. Harvesting body motion energy generates the power. Courtesy: UMass Amherst

I’m not quite as optimistic (it’s a long way from the lab to the marketplace) as the scientists do eventually note but this does seem promising (from a May 23, 2017 news item on Nanowerk),

A lightweight, comfortable jacket that can generate the power to light up a jogger at night may sound futuristic, but materials scientist Trisha Andrew at the University of Massachusetts Amherst could make one today.

In a new paper this month, she and colleagues outline how they have invented a way to apply breathable, pliable, metal-free electrodes to fabric and off-the-shelf clothing so it feels good to the touch and also transports enough electricity to power small electronics.

A May 23, 2017 University of Massachusetts Amherst news release (also on EurekAlert), which originated the news item,

She says, “Our lab works on textile electronics. We aim to build up the materials science so you can give us any garment you want, any fabric, any weave type, and turn it into a conductor. Such conducting textiles can then be built up into sophisticated electronics. One such application is to harvest body motion energy and convert it into electricity in such a way that every time you move, it generates power.” Powering advanced fabrics that can monitor health data remotely are important to the military and increasingly valued by the health care industry, she notes.

Generating small electric currents through relative movement of layers is called triboelectric charging, explains Andrew, who trained as a polymer chemist and electrical engineer. Materials can become electrically charged as they create friction by moving against a different material, like rubbing a comb on a sweater. “By sandwiching layers of differently materials between two conducting electrodes, a few microwatts of power can be generated when we move,” she adds.

In the current early online edition of Advanced Functional Materials, she and postdoctoral researcher Lu Shuai Zhang in her lab describe the vapor deposition method they use to coat fabrics with a conducting polymer, poly(3,4-ethylenedioxytiophene) also known as PEDOT, to make plain-woven, conducting fabrics that are resistant to stretching and wear and remain stable after washing and ironing. The thickest coating they put down is about 500 nanometers, or about 1/10 the diameter of a human hair, which retains a fabric’s hand feel.

The authors report results of testing electrical conductivity, fabric stability, chemical and mechanical stability of PEDOT films and textile parameter effects on conductivity for 14 fabrics, including five cottons with different weaves, linen and silk from a craft store.

“Our article describes the materials science needed to make these robust conductors,” Andrew says. “We show them to be stable to washing, rubbing, human sweat and a lot of wear and tear.” PEDOT coating did not change the feel of any fabric as determined by touch with bare hands before and after coating. Coating did not increase fabric weight by more than 2 percent. The work was supported by the Air Force Office of Scientific Research.

Until recently, she and Zhang point out, textile scientists have tended not to use vapor deposition because of technical difficulties and high cost of scaling up from the laboratory. But over the last 10 years, industries such as carpet manufacturers and mechanical component makers have shown that the technology can be scaled up and remain cost-effective. The researchers say their invention also overcomes the obstacle of power-generating electronics mounted on plastic or cladded, veneer-like fibers that make garments heavier and/or less flexible than off-the-shelf clothing “no matter how thin or flexible these device arrays are.”

“There is strong motivation to use something that is already familiar, such as cotton/silk thread, fabrics and clothes, and imperceptibly adapting it to a new technological application.” Andrew adds, “This is a huge leap for consumer products, if you don’t have to convince people to wear something different than what they are already wearing.”

Test results were sometimes a surprise, Andrew notes. “You’d be amazed how much stress your clothes go through until you try to make a coating that will survive a shirt being pulled over the head. The stress can be huge, up to a thousand newtons of force. For comparison, one footstep is equal to about 10 newtons, so it’s yanking hard. If your coating is not stable, a single pull like that will flake it all off. That’s why we had to show that we could bend it, rub it and torture it. That is a very powerful requirement to move forward.”

Andrew is director of wearable electronics at the Center for Personalized Health Monitoring in UMass Amherst’s Institute of Applied Life Sciences (IALS). Since the basic work reported this month was completed, her lab has also made a wearable heart rate monitor with an off-the-shelf fitness bra to which they added eight monitoring electrodes. They will soon test it with volunteers on a treadmill at the IALS human movement facility.

She explains that a hospital heart rate monitor has 12 electrodes, while the wrist-worn fitness devices popular today have one, which makes them prone to false positives. They will be testing a bra with eight electrodes, alone and worn with leggings that add four more, against a control to see if sensors can match the accuracy and sensitivity of what a hospital can do. As the authors note in their paper, flexible, body-worn electronics represent a frontier of human interface devices that make advanced physiological and performance monitoring possible.

For the future, Andrew says, “We’re working on taking any garment you give us and turning it into a solar cell so that as you are walking around the sunlight that hits your clothes can be stored in a battery or be plugged in to power a small electronic device.”

Zhang and Andrew believe their vapor coating is able to stick to fabrics by a process called surface grafting, which takes advantage of free bonds dangling on the surface chemically bonding to one end of the polymer coating, but they have yet to investigate this fully.

Here’s a link to and a citation for the paper,

Rugged Textile Electrodes for Wearable Devices Obtained by Vapor Coating Off-the-Shelf, Plain-Woven Fabrics by Lushuai Zhang, Marianne Fairbanks, and Trisha L. Andrew. Advanced Functional Materials DOI: 10.1002/adfm.201700415 Version of Record online: 2 MAY 2017

© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

Hacking the human brain with a junction-based artificial synaptic device

Earlier today I published a piece featuring Dr. Wei Lu’s work on memristors and the movement to create an artificial brain (my June 28, 2017 posting: Dr. Wei Lu and bio-inspired ‘memristor’ chips). For this posting I’m featuring a non-memristor (if I’ve properly understood the technology) type of artificial synapse. From a June 28, 2017 news item on Nanowerk,

One of the greatest challenges facing artificial intelligence development is understanding the human brain and figuring out how to mimic it.

Now, one group reports in ACS Nano (“Emulating Bilingual Synaptic Response Using a Junction-Based Artificial Synaptic Device”) that they have developed an artificial synapse capable of simulating a fundamental function of our nervous system — the release of inhibitory and stimulatory signals from the same “pre-synaptic” terminal.

Unfortunately, the American Chemical Society news release on EurekAlert, which originated the news item, doesn’t provide too much more detail,

The human nervous system is made up of over 100 trillion synapses, structures that allow neurons to pass electrical and chemical signals to one another. In mammals, these synapses can initiate and inhibit biological messages. Many synapses just relay one type of signal, whereas others can convey both types simultaneously or can switch between the two. To develop artificial intelligence systems that better mimic human learning, cognition and image recognition, researchers are imitating synapses in the lab with electronic components. Most current artificial synapses, however, are only capable of delivering one type of signal. So, Han Wang, Jing Guo and colleagues sought to create an artificial synapse that can reconfigurably send stimulatory and inhibitory signals.

The researchers developed a synaptic device that can reconfigure itself based on voltages applied at the input terminal of the device. A junction made of black phosphorus and tin selenide enables switching between the excitatory and inhibitory signals. This new device is flexible and versatile, which is highly desirable in artificial neural networks. In addition, the artificial synapses may simplify the design and functions of nervous system simulations.

Here’s how I concluded that this is not a memristor-type device (from the paper [first paragraph, final sentence]; a link and citation will follow; Note: Links have been removed)),

The conventional memristor-type [emphasis mine](14-20) and transistor-type(21-25) artificial synapses can realize synaptic functions in a single semiconductor device but lacks the ability [emphasis mine] to dynamically reconfigure between excitatory and inhibitory responses without the addition of a modulating terminal.

Here’s a link to and a citation for the paper,

Emulating Bilingual Synaptic Response Using a Junction-Based Artificial Synaptic Device by
He Tian, Xi Cao, Yujun Xie, Xiaodong Yan, Andrew Kostelec, Don DiMarzio, Cheng Chang, Li-Dong Zhao, Wei Wu, Jesse Tice, Judy J. Cha, Jing Guo, and Han Wang. ACS Nano, Article ASAP DOI: 10.1021/acsnano.7b03033 Publication Date (Web): June 28, 2017

Copyright © 2017 American Chemical Society

This paper is behind a paywall.

Dr. Wei Lu and bio-inspired ‘memristor’ chips

It’s been a while since I’ve featured Dr. Wei Lu’s work here. This April  15, 2010 posting features Lu’s most relevant previous work.) Here’s his latest ‘memristor’ work , from a May 22, 2017 news item on Nanowerk (Note: A link has been removed),

Inspired by how mammals see, a new “memristor” computer circuit prototype at the University of Michigan has the potential to process complex data, such as images and video orders of magnitude, faster and with much less power than today’s most advanced systems.

Faster image processing could have big implications for autonomous systems such as self-driving cars, says Wei Lu, U-M professor of electrical engineering and computer science. Lu is lead author of a paper on the work published in the current issue of Nature Nanotechnology (“Sparse coding with memristor networks”).

Lu’s next-generation computer components use pattern recognition to shortcut the energy-intensive process conventional systems use to dissect images. In this new work, he and his colleagues demonstrate an algorithm that relies on a technique called “sparse coding” to coax their 32-by-32 array of memristors to efficiently analyze and recreate several photos.

A May 22, 2017 University of Michigan news release (also on EurekAlert), which originated the news item, provides more information about memristors and about the research,

Memristors are electrical resistors with memory—advanced electronic devices that regulate current based on the history of the voltages applied to them. They can store and process data simultaneously, which makes them a lot more efficient than traditional systems. In a conventional computer, logic and memory functions are located at different parts of the circuit.

“The tasks we ask of today’s computers have grown in complexity,” Lu said. “In this ‘big data’ era, computers require costly, constant and slow communications between their processor and memory to retrieve large amounts data. This makes them large, expensive and power-hungry.”

But like neural networks in a biological brain, networks of memristors can perform many operations at the same time, without having to move data around. As a result, they could enable new platforms that process a vast number of signals in parallel and are capable of advanced machine learning. Memristors are good candidates for deep neural networks, a branch of machine learning, which trains computers to execute processes without being explicitly programmed to do so.

“We need our next-generation electronics to be able to quickly process complex data in a dynamic environment. You can’t just write a program to do that. Sometimes you don’t even have a pre-defined task,” Lu said. “To make our systems smarter, we need to find ways for them to process a lot of data more efficiently. Our approach to accomplish that is inspired by neuroscience.”

A mammal’s brain is able to generate sweeping, split-second impressions of what the eyes take in. One reason is because they can quickly recognize different arrangements of shapes. Humans do this using only a limited number of neurons that become active, Lu says. Both neuroscientists and computer scientists call the process “sparse coding.”

“When we take a look at a chair we will recognize it because its characteristics correspond to our stored mental picture of a chair,” Lu said. “Although not all chairs are the same and some may differ from a mental prototype that serves as a standard, each chair retains some of the key characteristics necessary for easy recognition. Basically, the object is correctly recognized the moment it is properly classified—when ‘stored’ in the appropriate category in our heads.”

Image of a memristor chip Image of a memristor chip Similarly, Lu’s electronic system is designed to detect the patterns very efficiently—and to use as few features as possible to describe the original input.

In our brains, different neurons recognize different patterns, Lu says.

“When we see an image, the neurons that recognize it will become more active,” he said. “The neurons will also compete with each other to naturally create an efficient representation. We’re implementing this approach in our electronic system.”

The researchers trained their system to learn a “dictionary” of images. Trained on a set of grayscale image patterns, their memristor network was able to reconstruct images of famous paintings and photos and other test patterns.

If their system can be scaled up, they expect to be able to process and analyze video in real time in a compact system that can be directly integrated with sensors or cameras.

The project is titled “Sparse Adaptive Local Learning for Sensing and Analytics.” Other collaborators are Zhengya Zhang and Michael Flynn of the U-M Department of Electrical Engineering and Computer Science, Garrett Kenyon of the Los Alamos National Lab and Christof Teuscher of Portland State University.

The work is part of a $6.9 million Unconventional Processing of Signals for Intelligent Data Exploitation project that aims to build a computer chip based on self-organizing, adaptive neural networks. It is funded by the [US] Defense Advanced Research Projects Agency [DARPA].

Here’s a link to and a citation for the paper,

Sparse coding with memristor networks by Patrick M. Sheridan, Fuxi Cai, Chao Du, Wen Ma, Zhengya Zhang, & Wei D. Lu. Nature Nanotechnology (2017) doi:10.1038/nnano.2017.83 Published online 22 May 2017

This paper is behind a paywall.

For the interested, there are a number of postings featuring memristors here (just use ‘memristor’ as your search term in the blog search engine). You might also want to check out ‘neuromorphic engineeering’ and ‘neuromorphic computing’ and ‘artificial brain’.

Light-based computation made better with silver

It’s pretty amazing to imagine a future where computers run on light but according to a May 16, 2017 news item on ScienceDaily the idea is not beyond the realms of possibility,

Tomorrow’s computers will run on light, and gold nanoparticle chains show much promise as light conductors. Now Ludwig-Maximilians-Universitaet (LMU) in Munich scientists have demonstrated how tiny spots of silver could markedly reduce energy consumption in light-based computation.

Today’s computers are faster and smaller than ever before. The latest generation of transistors will have structural features with dimensions of only 10 nanometers. If computers are to become even faster and at the same time more energy efficient at these minuscule scales, they will probably need to process information using light particles instead of electrons. This is referred to as “optical computing.”

The silver serves as a kind of intermediary between the gold particles while not dissipating energy. Capture: Liedl/Hohmann (NIM)

A March 15, 2017 LMU press release (also one EurekAlert), which originated the news item, describes a current use of light in telecommunications technology and this latest research breakthrough (the discrepancy in dates is likely due to when the paper was made available online versus in print),

Fiber-optic networks already use light to transport data over long distances at high speed and with minimum loss. The diameters of the thinnest cables, however, are in the micrometer range, as the light waves — with a wavelength of around one micrometer — must be able to oscillate unhindered. In order to process data on a micro- or even nanochip, an entirely new system is therefore required.

One possibility would be to conduct light signals via so-called plasmon oscillations. This involves a light particle (photon) exciting the electron cloud of a gold nanoparticle so that it starts oscillating. These waves then travel along a chain of nanoparticles at approximately 10% of the speed of light. This approach achieves two goals: nanometer-scale dimensions and enormous speed. What remains, however, is the energy consumption. In a chain composed purely of gold, this would be almost as high as in conventional transistors, due to the considerable heat development in the gold particles.

A tiny spot of silver

Tim Liedl, Professor of Physics at LMU and PI at the cluster of excellence Nanosystems Initiative Munich (NIM), together with colleagues from Ohio University, has now published an article in the journal Nature Physics, which describes how silver nanoparticles can significantly reduce the energy consumption. The physicists built a sort of miniature test track with a length of around 100 nanometers, composed of three nanoparticles: one gold nanoparticle at each end, with a silver nanoparticle right in the middle.

The silver serves as a kind of intermediary between the gold particles while not dissipating energy. To make the silver particle’s plasmon oscillate, more excitation energy is required than for gold. Therefore, the energy just flows “around” the silver particle. “Transport is mediated via the coupling of the electromagnetic fields around the so-called hot spots which are created between each of the two gold particles and the silver particle,” explains Tim Liedl. “This allows the energy to be transported with almost no loss, and on a femtosecond time scale.”

Textbook quantum model

The decisive precondition for the experiments was the fact that Tim Liedl and his colleagues are experts in the exquisitely exact placement of nanostructures. This is done by the DNA origami method, which allows different crystalline nanoparticles to be placed at precisely defined nanodistances from each other. Similar experiments had previously been conducted using conventional lithography techniques. However, these do not provide the required spatial precision, in particular where different types of metals are involved.

In parallel, the physicists simulated the experimental set-up on the computer – and had their results confirmed. In addition to classical electrodynamic simulations, Alexander Govorov, Professor of Physics at Ohio University, Athens, USA, was able to establish a simple quantum-mechanical model: “In this model, the classical and the quantum-mechanical pictures match very well, which makes it a potential example for the textbooks.”

Here’s a link to and c citation for the paper,

Hotspot-mediated non-dissipative and ultrafast plasmon passage by Eva-Maria Roller, Lucas V. Besteiro, Claudia Pupp, Larousse Khosravi Khorashad, Alexander O. Govorov, & Tim Liedl. Nature Physics (2017) doi:10.1038/nphys4120 Published online 15 May 2017

This paper is behind a paywall.

Gently measuring electrical signals in small animals with nano-SPEARs

This work comes from Rice University (Texas, US) according to an April 17, 2017 news item on Nanowerk,

Microscopic probes developed at Rice University have simplified the process of measuring electrical activity in individual cells of small living animals. The technique allows a single animal like a worm to be tested again and again and could revolutionize data-gathering for disease characterization and drug interactions.

The Rice lab of electrical and computer engineer Jacob Robinson has invented “nanoscale suspended electrode arrays” — aka nano-SPEARs — to give researchers access to electrophysiological signals from the cells of small animals without injuring them. Nano-SPEARs replace glass pipette electrodes that must be aligned by hand each time they are used.”

An April 17, 2017 Rice University news release (also on EurekAltert), which originated the news item, details the work,

“One of the experimental bottlenecks in studying synaptic behavior and degenerative diseases that affect the synapse is performing electrical measurements at those synapses,” Robinson said. “We set out to study large groups of animals under lots of different conditions to screen drugs or test different genetic factors that relate to errors in signaling at those synapses.”

Robinson’s early work at Rice focused on high-quality, high-throughput electrical characterization of individual cells. The new platform adapts the concept to probe the surface cells of nematodes, worms that make up 80 percent of all animals on Earth.

Most of what is known about muscle activity and synaptic transmission in the worms comes from the few studies that successfully used manually aligned glass pipettes to measure electrical activity from individual cells, Robinson said. However, this patch clamp technique requires time-consuming and invasive surgery that could negatively affect the data that is gathered from small research animals.

The platform developed by Robinson’s team works something like a toll booth for traveling worms. As each animal passes through a narrow channel, it is temporarily immobilized and pressed against one or several nano-SPEARS that penetrate its body-wall muscle and record electrical activity from nearby cells. That animal is then released, the next is captured and measured, and so on. Robinson said the device proved much faster to use than traditional electrophysiological cell measurement techniques.

The nano-SPEARs are created using standard thin-film deposition procedures and electron-beam or photolithography and can be made from less than 200 nanometers to more than 5 microns thick, depending on the size of animal to be tested. Because the nano-SPEARs can be fabricated on either silicon or glass, the technique easily combines with fluorescence microscopy, Robinson said.

The animals suitable for probing with a nano-SPEAR can be as large as several millimeters, like hydra, cousins of the jellyfish and the subject of an upcoming study. But nematodes known as Caenorhabditis elegans were practical for several reasons: First, Robinson said, they’re small enough to be compatible with microfluidic devices and nanowire electrodes. Second, there were a lot of them down the hall at the lab of Rice colleague Weiwei Zhong, who studies nematodes as transparent, easily manipulated models for signaling pathways that are common to all animals.

“I used to shy away from measuring electrophysiology because the conventional method of patch clamping is so technically challenging,” said Zhong, an assistant professor of biochemistry and cell biology and co-author of the paper. “Only a few graduate students or postdocs can do it. With Jacob’s device, even an undergraduate student can measure electrophysiology.”

“This meshes nicely with the high-throughput phenotyping she does,” Robinson said. “She can now correlate locomotive phenotypes with activity at the muscle cells. We believe that will be useful to study degenerative diseases centered around neuromuscular junctions.”

In fact, the labs have begun doing so. “We are now using this setup to profile worms with neurodegenerative disease models such as Parkinson’s and screen for drugs that reduce the symptoms,” Zhong said. “This would not be possible using the conventional method.”

Initial tests on C. elegans models for amyotrophic lateral sclerosis and Parkinson’s disease revealed for the first time clear differences in electrophysiological responses between the two, the researchers reported.

Testing the efficacy of drugs will be helped by the new ability to study small animals for long periods. “What we can do, for the first time, is look at electrical activity over a long period of time and discover interesting patterns of behavior,” Robinson said.

Some worms were studied for up to an hour, and others were tested on multiple days, said lead author Daniel Gonzales, a Rice graduate student in Robinson’s lab who took charge of herding nematodes through the microfluidic devices.

“It was in some way easier than working with isolated cells because the worms are larger and fairly sturdy,” Gonzales said. “With cells, if there’s too much pressure, they die. If they hit a wall, they die. But worms are really sturdy, so it was just a matter of getting them up against the electrodes and keeping them there.”

The team constructed microfluidic arrays with multiple channels that allowed testing of many nematodes at once. In comparison with patch-clamping techniques that limit labs to studying about one animal per hour, Robinson said his team measured as many as 16 nematodes per hour.

“Because this is a silicon-based technology, making arrays and producing recording chambers in high numbers becomes a real possibility,” he said.

A scanning electron micrograph shows a nano-SPEAR suspended midway between layers of silicon (grey) and photoresist material (pink) that form a recording chamber for immobilized nematodes. The high-throughput technology developed at Rice University can be adapted for other small animals and could enhance data-gathering for disease characterization and drug interactions. Courtesy of the Robinson Lab

Here’s a link to and a citation for the paper,

Scalable electrophysiology in intact small animals with nanoscale suspended electrode arrays by Daniel L. Gonzales, Krishna N. Badhiwala, Daniel G. Vercosa, Benjamin W. Avants, Zheng Liu, Weiwei Zhong, & Jacob T. Robinson. Nature Nanotechnology (2017) doi:10.1038/nnano.2017.55 Published online 17 April 2017

This paper is behind a paywall.