Author Archives: Maryse de la Giroday

Making nanoscale transistor chips out of thin air—sort of

Caption: The nano-gap transistors operating in air. As gaps become smaller than the mean-free path of electrons in air, there is ballistic electron transport. Credit: RMIT University

A November 19, 2018 news item on Nanowerk describes the ‘airy’ work ( Note: A link has been removed),

Researchers at RMIT University [Ausralia] have engineered a new type of transistor, the building block for all electronics. Instead of sending electrical currents through silicon, these transistors send electrons through narrow air gaps, where they can travel unimpeded as if in space.

The device unveiled in material sciences journal Nano Letters (“Metal–Air Transistors: Semiconductor-free field-emission air-channel nanoelectronics”), eliminates the use of any semiconductor at all, making it faster and less prone to heating up.

A November 19, 2018 RMIT University news release on EurkeAlert, which originated the news item, describes the work and possibilities in more detail,

Lead author and PhD candidate in RMIT’s Functional Materials and Microsystems Research Group, Ms Shruti Nirantar, said this promising proof-of-concept design for nanochips as a combination of metal and air gaps could revolutionise electronics.

“Every computer and phone has millions to billions of electronic transistors made from silicon, but this technology is reaching its physical limits where the silicon atoms get in the way of the current flow, limiting speed and causing heat,” Nirantar said.

“Our air channel transistor technology has the current flowing through air, so there are no collisions to slow it down and no resistance in the material to produce heat.”

The power of computer chips – or number of transistors squeezed onto a silicon chip – has increased on a predictable path for decades, roughly doubling every two years. But this rate of progress, known as Moore’s Law, has slowed in recent years as engineers struggle to make transistor parts, which are already smaller than the tiniest viruses, smaller still.

Nirantar says their research is a promising way forward for nano electronics in response to the limitation of silicon-based electronics.

“This technology simply takes a different pathway to the miniaturisation of a transistor in an effort to uphold Moore’s Law for several more decades,” Shruti said.

Research team leader Associate Professor Sharath Sriram said the design solved a major flaw in traditional solid channel transistors – they are packed with atoms – which meant electrons passing through them collided, slowed down and wasted energy as heat.

“Imagine walking on a densely crowded street in an effort to get from point A to B. The crowd slows your progress and drains your energy,” Sriram said.

“Travelling in a vacuum on the other hand is like an empty highway where you can drive faster with higher energy efficiency.”

But while this concept is obvious, vacuum packaging solutions around transistors to make them faster would also make them much bigger, so are not viable.

“We address this by creating a nanoscale gap between two metal points. The gap is only a few tens of nanometers, or 50,000 times smaller than the width of a human hair, but it’s enough to fool electrons into thinking that they are travelling through a vacuum and re-create a virtual outer-space for electrons within the nanoscale air gap,” he said.

The nanoscale device is designed to be compatible with modern industry fabrication and development processes. It also has applications in space – both as electronics resistant to radiation and to use electron emission for steering and positioning ‘nano-satellites’.

“This is a step towards an exciting technology which aims to create something out of nothing to significantly increase speed of electronics and maintain pace of rapid technological progress,” Sriram said.

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

Metal–Air Transistors: Semiconductor-free field-emission air-channel nanoelectronics by
Shruti Nirantar, Taimur Ahmed, Guanghui Ren, Philipp Gutruf, Chenglong Xu, Madhu Bhaskaran, Sumeet Walia, and Sharath Sriram. Nano Lett., DOI: 10.1021/acs.nanolett.8b02849 Publication Date (Web): November 16, 2018

Copyright © 2018 American Chemical Society

This paper is behind a paywall.

Whispering in the Dark: Updates from Underground Science a June 12, 2019 talk in Vancouver (Canada)

The Society of Italian Researchers and Professionals in Western Canada (ARPICO) is hosting the intriguing ‘Whispering in the Dark …’ talk about underground science being held prior to the organization’s annual general meeting. From a May 21, 2019 ARPICO announcement (received via email),

… on June 12th, 2019 at the Italian Cultural Centre. ARPICO is proud to host Dr. Silvia Scorza, who will be presenting on the topic of underground science (literally underground) at SNOLAB, where research is conducted in fields of fundamental science that require shielding from external radiation such as cosmic rays. SNOLAB (SNO stands for Sudbury Neutrino Observatory) is a Canadian research laboratory located 2 km underground in Sudbury, Ontario. This presentation will give a unique and interesting perspective into the research that is conducted mostly out of the public view and discussion, but contributes critically to our scientific advances. Applications found in medicine, national security, industry, computing, science, and workforce development, illustrate a long and growing list of beneficial practical applications with contributions from particle physics.

Please read below to learn more about our speaker and topic.

Ahead of the speaking event, ARPICO will be holding its 2019 Annual General Meeting in the same location. We encourage everyone to participate in the AGM, have their say on ARPICO’s matters and possibly volunteer for the Board of Directors. ARPICO is made by all of its members, not just the Board, and it is therefore paramount that you all come, let us know what your wishes are for the Society and tell us how we can do better together as we go forward.

If you are driving to the venue, there is plenty of free parking space.  Please refer to the attached parking map for information on where not to park however, just to be sure.

We look forward to seeing everyone there.

The evening agenda is as follows:
6:00 pm to 6:45 pm – Annual General Meeting  [ Doors Open for Registration at 5:50 pm ]
7:00 pm – Start of the evening event with introductions & lecture by Dr. Silvia Scorza [ Doors Open for Registration at 6:45 pm ]
~8:00 pm – Q & A Period
to follow – Mingling & Refreshments until about 9:30 pm
If you have not already done so, please register for the event by visiting the EventBrite link or RSVPing to info@arpico.ca.

Further details are also available at arpico.ca and Eventbrite.

Whispering in the Dark: Updates from Underground Scienc

Based at a depth of 2 km in the Vale Creighton mine near Sudbury, Ontario, SNOLAB is an underground scientific environment that provides the conditions necessary for experiments dealing with rare interactions that have to be shielded from external radiation. The lab hosts an international community involved in a number of fundamental physics (neutrino and dark matter) as well as new biology and genomic experiments making use of the unique facility. In this lecture, Dr. Scorza will offer an overview on the life of an “underground scientist” and the immense possibilities of discovery that facilities like SNOLAB make available to our society.

Dr. Silvia Scorza was born and raised in Genoa, Italy. She received her B.Sc. and M.Sc. in Physics from the University of Genoa in 2003 and 2006, respectively. She then moved to the University Claude Bernard Lyon1 (UCBL1), France, where she obtained her Ph.D. in 2009. She has then held postdoctoral positions in France at the Institut de Physique Nucléaire de Lyon, in the U.S. at the Southern Methodist University in Dallas (TX) and later in Germany at the Karlsruhe Institute of Technology. Silvia is currently a research scientist at SNOLAB and adjunct professor at Laurentian University working on the SuperCDMS SNOLAB direct dark matter search experiment and the cryogenic test facility CUTE.
 
WHEN (AGM): Wednesday, June 12th, 2019 at 6:00pm (doors open at 5:50pm)
WHEN (EVENT): Wednesday, June 12th, 2019 at 7:00pm (doors open at 6:45pm)
WHERE: Italian Cultural Centre – Museum & Art Gallery – 3075 Slocan St, Vancouver, BC, V5M 3E4

RSVP: Please RSVP at EventBrite (http://whispersinthedark.eventbrite.ca/) or email info@arpico.ca
 
Tickets are Neede

Tickets are FREE, but all individuals are requested to obtain “free-admission” tickets on EventBrite site due to limited seating at the venue. Organizers need accurate registration numbers to manage wait lists and prepare name tags.

All ARPICO events are 100% staffed by volunteer organizers and helpers, however, room rental, stationery, and guest refreshments are costs incurred and underwritten by members of ARPICO. Therefore to be fair, all audience participants are asked to donate to the best of their ability at the door or via EventBrite to “help” defray costs of the event.
 
FAQs
Where can I contact the organizer with any questions? info@arpico.ca
Do I have to bring my printed ticket to the event? No, you do not. Your name will be on our Registration List at the Check-in Desk.
Is my registration/ticket transferrable? If you are unable to attend, another person may use your ticket. Please send us an email at info@arpico.ca of this substitution to correct our audience Registration List and to prepare guest name tags.
Can I update my registration information? Yes. If you have any questions, contact us at info@arpico.ca
I am having trouble using EventBrite and cannot reserve my ticket(s). Can someone at ARPICO help me with my ticket reservation? Of course, simply send your ticket request to us at info@arpico.ca so we help you.
 
What are my transport/parking options?
Bus/Train: The Millenium Line Renfrew Skytrain station is a 5 minute walk from the Italian Cultural Centre.
Parking: Free Parking is vastly available at the ICC’s own parking lot.  …

We look forward to seeing you there.

ARPICO
www.arpico.ca

You can find out more about SNOLAB here. There’s even a virtual tour.

Lifesaving moths and nanomagnets

Rice University bioengineers use a magnetic field to activate nanoparticle-attached baculoviruses in a tissue. The viruses, which normally infect alfalfa looper moths, are modified to deliver gene-editing DNA code only to cells that are targeted with magnetic field-induced local transduction. Courtesy of the Laboratory of Biomolecular Engineering and Nanomedicine

Kudos to whomever put that diagram together! That’s a lot of well conveyed information.

Now for the details about how this technology might save lives. From a November 13, 2018 news item on Nanowerk,

A new technology that relies on a moth-infecting virus and nanomagnets could be used to edit defective genes that give rise to diseases like sickle cell, muscular dystrophy and cystic fibrosis.

Rice University bioengineer Gang Bao has combined magnetic nanoparticles with a viral container drawn from a particular species of moth to deliver CRISPR/Cas9 payloads that modify genes in a specific tissue or organ with spatial control.

A November 12, 2018 Rice University news release (also on EurekAlert published on November 13, 2018), which originated the news item, provides detail,

Because magnetic fields are simple to manipulate and, unlike light, pass easily through tissue, Bao and his colleagues want to use them to control the expression of viral payloads in target tissues by activating the virus that is otherwise inactivated in blood.

The research appears in Nature Biomedical Engineering. In nature, CRISPR/Cas9 bolsters microbes’ immune systems by recording the DNA of invaders. That gives microbes the ability to recognize and attack returning invaders, but scientists have been racing to adapt CRISPR/Cas9 to repair mutations that cause genetic diseases and to manipulate DNA in laboratory experiments.

CRISPR/Cas9 has the potential to halt hereditary disease – if scientists can get the genome-editing machinery to the right cells inside the body. But roadblocks remain, especially in delivering the gene-editing payloads with high efficiency.

Bao said it will be necessary to edit cells in the body to treat many diseases. “But efficiently delivering genome-editing machinery into target tissue in the body with spatial control remains a major challenge,” Bao said. “Even if you inject the viral vector locally, it can leak to other tissues and organs, and that could be dangerous.”

The delivery vehicle developed by Bao’s group is based on a virus that infects Autographa californica, aka the alfalfa looper, a moth native to North America. The cylindrical baculovirus vector (BV), the payload-carrying part of the virus, is considered large at up to 60 nanometers in diameter and 200-300 nanometers in length. That’s big enough to transport more than 38,000 base pairs of DNA, which is enough to supply multiple gene-editing units to a target cell, Bao said.

He said the inspiration to combine BV and magnetic nanoparticles came from discussions with Rice postdoctoral researcher and co-lead author Haibao Zhu, who learned about the virus during a postdoctoral stint in Singapore but knew nothing about magnetic nanoparticles until he joined the Bao lab. The Rice team had previous experience using iron oxide nanoparticles and an applied magnetic field to open blood vessel walls just enough to let large-molecule drugs pass through.

“We really didn’t know if this would work for gene editing or not, but we thought, ‘worth a shot,'” Bao said.

The researchers use the magnetic nanoparticles to activate BV and deliver gene-editing payloads only where they’re needed. To do this, they take advantage of an immune-system protein called C3 that normally inactivates baculoviruses.

“If we combine BV with magnetic nanoparticles, we can overcome this deactivation by applying the magnetic field,” Bao said. “The beauty is that when we deliver it, gene editing occurs only at the tissue, or the part of the tissue, where we apply the magnetic field.”

Application of the magnetic field allows BV transduction, the payload-delivery process that introduces gene-editing cargo into the target cell. The payload is also DNA, which encodes both a reporter gene and the CRISPR/Cas9 system.

In tests, the BV was loaded with green fluorescent proteins or firefly luciferase. Cells with the protein glowed brightly under a microscope, and experiments showed the magnets were highly effective at targeted delivery of BV cargoes in both cell cultures and lab animals.

Bao noted his and other labs are working on the delivery of CRISPR/Cas9 with adeno-associated viruses (AAV), but he said BV’s capacity for therapeutic cargo is roughly eight times larger. “However, it is necessary to make BV transduction into target cells more efficient,” he said.

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

Spatial control of in vivo CRISPR–Cas9 genome editing via nanomagnets by Haibao Zhu, Linlin Zhang, Sheng Tong, Ciaran M. Lee, Harshavardhan Deshmukh, & Gang Bao. Nature Biomedical Engineering (2018) DOI: https://doi.org/10.1038/s41551-018-0318-7 Published: 12 November 2018

This paper is behind a paywall.

Defending nanoelectronics from cyber attacks

There’s a new program at the University of Stuttgart (Germany) and their call for projects was recently announced. First, here’s a description of the program in a May 30, 2019 news item on Nanowerk,

Today’s societies critically depend on electronic systems. Past spectacular cyber-attacks have clearly demonstrated the vulnerability of existing systems and the need to prevent such attacks in the future. The majority of available cyber-defenses concentrate on protecting the software part of electronic systems or their communication interfaces.

However, manufacturing technology advancements and the increasing hardware complexity provide a large number of challenges so that the focus of attackers has shifted towards the hardware level. We saw already evidence for powerful and successful hardware-level attacks, including Rowhammer, Meltdown and Spectre.

These attacks happened on products built using state-of-the-art microelectronic technology, however, we are facing completely new security challenges due to the ongoing transition to radically new types of nanoelectronic devices, such as memristors, spintronics, or carbon nanotubes and graphene based transistors.

The use of such emerging nanotechnologies is inevitable to address the key challenges related to energy efficiency, computing power and performance. Therefore, the entire industry, are switching to emerging nano-electronics alongside scaled CMOS technologies in heterogeneous integrated systems.

These technologies come with new properties and also facilitate the development of radically different computer architectures. The new technologies and architectures provide new opportunities for achieving security targets, but also raise questions about their vulnerabilities to new types of hardware attacks.

A May 28, 2019 University of Stuttgart press release provides more information about the program and the call for projects,

Whether it’s cars, industrial plants or the government network, spectacular cyber attacks over the past few months have shown how vulnerable modern electronic systems are. The aim of the new Priority Program “Nano Security”, which is coordinated by the University of Stuttgart, is protecting you and preventing the cyber attacks of the future. The program, which is funded by the German Research Foundation (DFG), emphasizes making the hardware into a reliable foundation of a system or a layer of security.

The challenges of nanoelectronics

Completely new challenges also emerge as a result of the switch to radically new nanoelectronic components, which for example are used to master the challenges of the future in terms of energy efficiency, computing power and secure data transmission. For example, memristors (components which are not just used to store information but also function as logic modules), the spintronics, which exploit quantum-mechanical effects, or carbon nanotubes.

The new technologies, as well as the fundamentally different computer architecture associated with them, offer new opportunities for cryptographic primitives in order to achieve an even more secure data transmission. However, they also raise questions about their vulnerability to new types of hardware attacks.

The problem is part of the solution

In this context, a better understanding should be developed of what consequences the new nanoelectronic technologies have for the security of circuits and systems as part of the new Priority Program. Here, the hardware is not just thought of as part of the problem but also as an important and necessary part of the solution to security problems. The starting points here for example are the hardware-based generation of cryptographic keys, the secure storage and processing of sensitive data, and the isolation of system components which is guaranteed by the hardware. Lastly, it should be ensured that an attack cannot be spread further by the system.

In this process, the scientists want to assess the possible security risks and weaknesses which stem from the new type of nanoelectronics. Furthermore, they want to develop innovative approaches for system security which are based on nanoelectronics as a security anchor.

The Priority Program promotes cooperation between scientists, who develop innovative security solutions for the computer systems of the future on different levels of abstraction. Likewise, it makes methods available to system designers to keep ahead in the race between attackers and security measures over the next few decades.

The call has started

The DFG Priority Program “Nano Security. From Nano-Electronics to Secure Systems“ (SPP 2253) is scheduled to last for a period of six years. The call for projects for the first three-year funding period was advertised a few days ago, and the first projects are set to start at the beginning of 2020.

For more information go to the Nano Security: From Nano-Electronics to Secure Systems webpage on the University of Stuttgart website.

Chen Qiufan, garbage, and Chinese science fiction stories

Garbage has been dominating Canadian news headlines for a few weeks now. First, it was Canadian garbage in the Philippines and now it’s Canadian garbage in Malaysia. Interestingly, we’re also having problems with China, since December 2018, when we detained a top executive from Huawe, a China-based international telecommunicatons company, in accordance with an official request from the US government and, in accordance, with what Prime Minister Justin Trudeau calls the ‘rule of law’. All of this provides an interesting backdrop (for Canadians anyway) on the topic of China, garbage, and science fiction.

A May 16, 2019 article by Anjie Zheng for Fast Company explores some of the latest and greatest from China’s science fiction writing community,

Like any good millennial, I think about my smartphone, to the extent that I do at all, in terms of what it does for me. It lets me message friends, buy stuff quickly, and amass likes. I hardly ever think about what it actually is—a mass of copper wires, aluminum alloys, and lithium battery encased in glass—or where it goes when I upgrade.

Chen Qiufan wants us to think about that. His debut novel, Waste Tide, is set in a lightly fictionalized version of Guiyu, the world’s largest electronic waste disposal. First published in Chinese in 2013, the book was recently released in the U.S. with a very readable translation into English by Ken Liu.

Chen, who has been called “China’s William Gibson,” is part of a younger generation of sci-fi writers who have achieved international acclaim in recent years. Liu Cixin became the first Chinese to win the prestigious Hugo Award for his Three Body Problem in 2015. The Wandering Earth, based on a short story by Liu, became China’s first science-fiction blockbuster when it was released in 2018. It was the highest-grossing film in the fastest-growing film market in the world last year and was recently scooped up by Netflix.

Aynne Kokas in a March 13, 2019 article for the Washington Post describes how the hit film, The Wandering Earth, fits into an overall Chinese-led movie industry focused on the future and Hollywood-like, i. e. like US movie industry, domination,

“The Wandering Earth,” directed by Frant Gwo, takes place in a future where the people of Earth must flee their sun as it swells into a red giant. Thousands of engines — the first of them constructed in Hangzhou, one of China’s tech hubs — propel the entire planet toward a new solar system, while everyone takes refuge from the cold in massive underground cities. On the surface, the only visible reminders of the past are markers of China’s might. The Shanghai Tower, the Oriental Pearl Tower and a stadium for the Shanghai 2044 Olympics all thrust out of the ice, having apparently survived the journey’s tsunamis, deep freeze and cliff-collapsing earthquakes.

The movie is China’s first big-budget sci-fi epic, and its production was ambitious, involving some 7,000 workers and 10,000 specially-built props. Audience excitement was correspondingly huge: Nearly half a million people wrote reviews of the film on Chinese social network site Douban. Having earned over $600 million in domestic sales, “The Wandering Earth” marks a major achievement for the country’s film industry.

It is also a major achievement for the Chinese government.

Since opening up the country’s film market in 2001, the Chinese government has aspired to learn from Hollywood how to make commercially appealing films, as I detail in my book “Hollywood Made in China.” From initial private offerings for state media companies, to foreign investment in films, studios and theme parks, the government allowed outside capital and expertise to grow the domestic commercial film industry — but not at the expense of government oversight. This policy’s underlying aim was to expand China’s cultural clout and political influence.

Until recently, Hollywood films dominated the country’s growing box office. That finally changed in 2015, with the release of major local blockbusters “Monster Hunt” and “Lost in Hong Kong.” The proliferation of homegrown hits signaled that the Chinese box office profits no longer depend on Hollywood studio films — sending an important message to foreign trade negotiators and studios.

Kokas provides some insight into how the Chinese movie industry is designed to further the Chinese government’s vision of the future. As a Canadian, I don’t see that much difference between the US and China industry’s vision. Both tout themselves as the answer to everything, both target various geographic regions for the ‘bad guys’, and both tout their national moral superiority in their films. I suppose the same can be said for most countries’ film industries but both China and the US can back themselves with economic might.

Zheng’s article delves deeper into garbage, and Chen Qiufan’s science fiction while illuminating the process of changing a ‘good guy’ into a ‘bad guy’,

Chen, 37, grew up a few miles from the real Guiyu. Mountains of scrap electronics are shipped there every year from around the world. Thousands of human workers sort through the junk for whatever can be reduced to reusable precious metals. They strip wires and disassemble circuit boards, soaking them in acid baths for bits of copper, tin, platinum, and gold. Whatever can’t be processed is burned. The water in Guiyu has been so contaminated it is undrinkable; the air is toxic. The workers, migrants from poor rural areas in China, have an abnormally high rate of respiratory diseases and cancer.

For the decades China was revving its economic engine, authorities were content to turn a blind eye to the human costs of the recycling business. It was an economic win-win. For developed countries like the U.S., it’s cheaper to ship waste to places like China than trying to recycle it themselves. And these shipments create jobs and profits for the Chinese.

In recent years, however, steps have been taken to protect workers and the environment in China. …

Waste Tide highlights the danger of “throw-away culture,” says Chen, also known in English as Stanley Chan. When our personal electronics stop serving us, whether because they break or our lust for the newest specs get the better of us, we toss them. Hopefully we’re conscientious enough to bring them to local recyclers that claim they’ll dispose of them properly. But that’s likely the end of our engagement with the trash. Out of sight, out of mind.

Fiction, and science fiction in particular, is an apt medium for Chen to probe the consequences of this arrangement. “It’s not journalism,” he says. Instead, the story is an imaginative, action-packed tale of power imbalances, and the individual characters that think they’re doing good. Waste Tide culminates, expectedly, in an insurgency of the workers against their exploitative overlords.

Guiyu has been fictionalized in Waste Tide as “Silicon Isle.” (A homophone of the Chinese character “gui” translates to “Silicon,” and “yu” is an island). The waste hell is ruled by three ruthless family clans, dominated by the Luo clan. They treat workers as slaves and derisively call them “waste people.”

Technology in the near-future has literally become extensions of selves and only exacerbates class inequality. Prosthetic inner ears improve balance; prosthetic limbs respond to mental directives; helmets heighten natural senses. The rich “switch body parts as easily as people used to switch phones.” Those with fewer means hack discarded prosthetics to get the same kick. When they’re no longer needed, synthetic body parts contaminated with blood and bodily fluids are added to the detritus.

At the center of the story is Mimi, a migrant worker who dreams of earning enough money to return home and live a quiet life. She strikes up a relationship with Kaizong, a Chinese-American college graduate trying to rediscover his roots. But the good times are short-lived. The boss of the Luo clan becomes convinced that Mimi holds the key to rousing his son from his coma and soon kidnaps the hapless girl.

For all the advanced science, there is a backwards superstition that animates Silicon Isle. [emphasis mine] The clan bosses subscribe to “a simple form of animism.” They pray to the wind and sea for ample supplies of waste. They sacrifice animals (and some humans) to bring them luck, and use local witches to exorcise evil spirits. Boss Luo has Mimi kidnapped and tortured in an effort to appease the gods in the hopes of waking up his comatose son. The torture of Mimi infects her with a mysterious disease that splits her consciousness. The waste people are enraged by her violation, which eventually sparks a war against the ruling clans. [emphasis mine]

A parallel narrative involves an American, Scott Brandle, who works for an environmental company. While in town trying to set up a recycling facility, he stumbles onto the truth about the virus that may have infected Mimi: a chemical weapon developed and used by the U.S. [emphasis mine] years earlier. Invented by a Japanese researcher [emphasis mine] working in the U.S., the drug is capable of causing mass hallucinations and terror. When Brandle learns that Mimi may have been infected with this virus, he wants a piece of her [emphasis mine] too, so that scientists back home can study its effects.

Despite portraying the future of China in a less-than-positive light, [emphasis mine] Waste Tide has not been banned–a common result for works that displease Beijing; instead, the book won China’s prestigious Nebula award for science fiction, and is about to be reprinted on the mainland. …

An interview with Chen (it’s worthwhile to read his take on what he’s doing) follows the plot description in this intriguing and what seems to be a sometimes disingenuous article.

The animism and the war against the ruling class? It reminds me a little of the tales told about old Chine and Mao’s campaign to overthrow the ruling classes who had kept control of the proletariat, in part, by encouraging ‘superstitious religious belief’.

As far as I’m concerned the interpretation can go either or both ways: a critique of the current government’s policies and where they might lead in the future and/or a reference back to the glorious rising of China’s communist government. Good fiction always contains ambiguity; it’s what fuels courses in literature.

Also, the bad guys are from the US and Japan, countries which have long been allied with each other and with which China has some serious conflicts.

Interesting, non? And, it’s not that different from what you’ll see in US (or any other country’s for that matter) science fiction wiring and movies, except that the heroes are Chinese.

Getting back to the garbage in the Philippines, there are 69 containers on their way back to Canada as of May 30, 2019. As for why all this furor about Canadian garbage in the Philippines and Malaysia, it’s hard to believe that Canada is the only sinner. Of course, we are in China’s bad books due to the Huawei executive’s detention here (she is living in her home in Vancouver and goes out and about as she wishes, albeit under surveillance).

Anyway, I can’t help but wonder if indirect pressure is being exerted by China or if the Philippines and Malaysia have been incentivized in some way by China. The timing has certainly been interesting.

Political speculation aside, it’s probably a good thing that countries are refusing to take our garbage. As I’m sure more than one environmentalist would be happy to point out, it’s about time we took care of our own mess.

Two approaches to memristors

Within one day of each other in October 2018, two different teams working on memristors with applications to neuroprosthetics and neuromorphic computing (brainlike computing) announced their results.

Russian team

An October 15, 2018 (?) Lobachevsky University press release (also published on October 15, 2018 on EurekAlert) describes a new approach to memristors,

Biological neurons are coupled unidirectionally through a special junction called a synapse. An electrical signal is transmitted along a neuron after some biochemical reactions initiate a chemical release to activate an adjacent neuron. These junctions are crucial for cognitive functions, such as perception, learning and memory.

A group of researchers from Lobachevsky University in Nizhny Novgorod investigates the dynamics of an individual memristive device when it receives a neuron-like signal as well as the dynamics of a network of analog electronic neurons connected by means of a memristive device. According to Svetlana Gerasimova, junior researcher at the Physics and Technology Research Institute and at the Neurotechnology Department of Lobachevsky University, this system simulates the interaction between synaptically coupled brain neurons while the memristive device imitates a neuron axon.

A memristive device is a physical model of Chua’s [Dr. Leon Chua, University of California at Berkeley; see my May 9, 2008 posting for a brief description Dr. Chua’s theory] memristor, which is an electric circuit element capable of changing its resistance depending on the electric signal received at the input. The device based on a Au/ZrO2(Y)/TiN/Ti structure demonstrates reproducible bipolar switching between the low and high resistance states. Resistive switching is determined by the oxidation and reduction of segments of conducting channels (filaments) in the oxide film when voltage with different polarity is applied to it. In the context of the present work, the ability of a memristive device to change conductivity under the action of pulsed signals makes it an almost ideal electronic analog of a synapse.

Lobachevsky University scientists and engineers supported by the Russian Science Foundation (project No.16-19-00144) have experimentally implemented and theoretically described the synaptic connection of neuron-like generators using the memristive interface and investigated the characteristics of this connection.

“Each neuron is implemented in the form of a pulse signal generator based on the FitzHugh-Nagumo model. This model provides a qualitative description of the main neurons’ characteristics: the presence of the excitation threshold, the presence of excitable and self-oscillatory regimes with the possibility of a changeover. At the initial time moment, the master generator is in the self-oscillatory mode, the slave generator is in the excitable mode, and the memristive device is used as a synapse. The signal from the master generator is conveyed to the input of the memristive device, the signal from the output of the memristive device is transmitted to the input of the slave generator via the loading resistance. When the memristive device switches from a high resistance to a low resistance state, the connection between the two neuron-like generators is established. The master generator goes into the oscillatory mode and the signals of the generators are synchronized. Different signal modulation mode synchronizations were demonstrated for the Au/ZrO2(Y)/TiN/Ti memristive device,” – says Svetlana Gerasimova.

UNN researchers believe that the next important stage in the development of neuromorphic systems based on memristive devices is to apply such systems in neuroprosthetics. Memristive systems will provide a highly efficient imitation of synaptic connection due to the stochastic nature of the memristive phenomenon and can be used to increase the flexibility of the connections for neuroprosthetic purposes. Lobachevsky University scientists have vast experience in the development of neurohybrid systems. In particular, a series of experiments was performed with the aim of connecting the FitzHugh-Nagumo oscillator with a biological object, a rat brain hippocampal slice. The signal from the electronic neuron generator was transmitted through the optic fiber communication channel to the bipolar electrode which stimulated Schaffer collaterals (axons of pyramidal neurons in the CA3 field) in the hippocampal slices. “We are going to combine our efforts in the design of artificial neuromorphic systems and our experience of working with living cells to improve flexibility of prosthetics,” concludes S. Gerasimova.

The results of this research were presented at the 38th International Conference on Nonlinear Dynamics (Dynamics Days Europe) at Loughborough University (Great Britain).

This diagram illustrates an aspect of the work,

Caption: Schematic of electronic neurons coupling via a memristive device. Credit: Lobachevsky University

US team

The American Institute of Physics (AIP) announced the publication of a ‘memristor paper’ by a team from the University of Southern California (USC) in an October 16, 2018 news item on phys.org,

Just like their biological counterparts, hardware that mimics the neural circuitry of the brain requires building blocks that can adjust how they synapse, with some connections strengthening at the expense of others. One such approach, called memristors, uses current resistance to store this information. New work looks to overcome reliability issues in these devices by scaling memristors to the atomic level.

An October 16, 2018 AIP news release (also on EurekAlert), which originated the news item, delves further into the particulars of this particular piece of memristor research,

A group of researchers demonstrated a new type of compound synapse that can achieve synaptic weight programming and conduct vector-matrix multiplication with significant advances over the current state of the art. Publishing its work in the Journal of Applied Physics, from AIP Publishing, the group’s compound synapse is constructed with atomically thin boron nitride memristors running in parallel to ensure efficiency and accuracy.

The article appears in a special topic section of the journal devoted to “New Physics and Materials for Neuromorphic Computation,” which highlights new developments in physical and materials science research that hold promise for developing the very large-scale, integrated “neuromorphic” systems of tomorrow that will carry computation beyond the limitations of current semiconductors today.

“There’s a lot of interest in using new types of materials for memristors,” said Ivan Sanchez Esqueda, an author on the paper. “What we’re showing is that filamentary devices can work well for neuromorphic computing applications, when constructed in new clever ways.”

Current memristor technology suffers from a wide variation in how signals are stored and read across devices, both for different types of memristors as well as different runs of the same memristor. To overcome this, the researchers ran several memristors in parallel. The combined output can achieve accuracies up to five times those of conventional devices, an advantage that compounds as devices become more complex.

The choice to go to the subnanometer level, Sanchez said, was born out of an interest to keep all of these parallel memristors energy-efficient. An array of the group’s memristors were found to be 10,000 times more energy-efficient than memristors currently available.

“It turns out if you start to increase the number of devices in parallel, you can see large benefits in accuracy while still conserving power,” Sanchez said. Sanchez said the team next looks to further showcase the potential of the compound synapses by demonstrating their use completing increasingly complex tasks, such as image and pattern recognition.

Here’s an image illustrating the parallel artificial synapses,

Caption: Hardware that mimics the neural circuitry of the brain requires building blocks that can adjust how they synapse. One such approach, called memristors, uses current resistance to store this information. New work looks to overcome reliability issues in these devices by scaling memristors to the atomic level. Researchers demonstrated a new type of compound synapse that can achieve synaptic weight programming and conduct vector-matrix multiplication with significant advances over the current state of the art. They discuss their work in this week’s Journal of Applied Physics. This image shows a conceptual schematic of the 3D implementation of compound synapses constructed with boron nitride oxide (BNOx) binary memristors, and the crossbar array with compound BNOx synapses for neuromorphic computing applications. Credit: Ivan Sanchez Esqueda

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

Efficient learning and crossbar operations with atomically-thin 2-D material compound synapses by Ivan Sanchez Esqueda, Huan Zhao and Han Wang. The article will appear in the Journal of Applied Physics Oct. 16, 2018 (DOI: 10.1063/1.5042468).

This paper is behind a paywall.

*Title corrected from ‘Two approaches to memristors featuring’ to ‘Two approaches to memristors’ on May 31, 2019 at 1455 hours PDT.

Unusual appetite for gold

This bacterium (bacteria being the plural) loves gold, which is lucky for anyone trying to develop artificial photosynthesis.From an October 9, 2018 news item on ScienceDaily,

A bacterium named Moorella thermoacetica won’t work for free. But UC Berkeley [University of California at Berkeley] researchers have figured out it has an appetite for gold. And in exchange for this special treat, the bacterium has revealed a more efficient path to producing solar fuels through artificial photosynthesis.

An October 5, 2018 UC Berkeley news release by Theresa Duque (also on EurekAlert but published on October 9, 2018), which originated the news item, expands on the theme,

M. thermoacetica first made its debut as the first non-photosensitive bacterium to carry out artificial photosynthesis (link is external) in a study led by Peidong Yang, a professor in UC Berkeley’s College of Chemistry. By attaching light-absorbing nanoparticles made of cadmium sulfide (CdS) to the bacterial membrane exterior, the researchers turned M. thermoacetica into a tiny photosynthesis machine, converting sunlight and carbon dioxide into useful chemicals.

Now Yang and his team of researchers have found a better way to entice this CO2-hungry bacterium into being even more productive. By placing light-absorbing gold nanoclusters inside the bacterium, they have created a biohybrid system that produces a higher yield of chemical products than previously demonstrated. The research, funded by the National Institutes of Health, was published on Oct. 1 in Nature Nanotechnology (link is external).

For the first hybrid model, M. thermoacetica-CdS, the researchers chose cadmium sulfide as the semiconductor for its ability to absorb visible light. But because cadmium sulfide is toxic to bacteria, the nanoparticles had to be attached to the cell membrane “extracellularly,” or outside the M. thermoacetica-CdS system. Sunlight excites each cadmium-sulfide nanoparticle into generating a charged particle known as an electron. As these light-generated electrons travel through the bacterium, they interact with multiple enzymes in a process known as “CO2 reduction,” triggering a cascade of reactions that eventually turns CO2 into acetate, a valuable chemical for making solar fuels.

But within the extracellular model, the electrons end up interacting with other chemicals that have no part in turning CO2 into acetate. And as a result, some electrons are lost and never reach the enzymes. So to improve what’s known as “quantum efficiency,” or the bacterium’s ability to produce acetate each time it gains an electron, the researchers found another semiconductor: nanoclusters made of 22 gold atoms (Au22), a material that M. thermoacetica took a surprising shine to.

A single nanocluster of 22 gold atoms

Figure: A single nanocluster of 22 gold atoms – Au22 – is only 1 nanometer in diameter, allowing it to easily slip through the bacterial cell wall.

“We selected Au22 because it’s ideal for absorbing visible light and has the potential for driving the CO2 reduction process, but we weren’t sure whether it would be compatible with the bacteria,” Yang said. “When we inspected them under the microscope, we discovered that the bacteria were loaded with these Au22 clusters – and were still happily alive.”

Imaging of the M. thermoacetica-Au22 system was done at UC Berkeley’s Molecular Imaging Center (link is external).

The researchers also selected Au22 ­– dubbed by the researchers as “magic” gold nanoclusters – for its ultrasmall size: A single Au22nanocluster is only 1 nanometer in diameter, allowing each nanocluster to easily slip through the bacterial cell wall.

“By feeding bacteria with Au22 nanoclusters, we’ve effectively streamlined the electron transfer process for the CO2 reduction pathway inside the bacteria, as evidenced by a 2.86 percent quantum efficiency – or 33 percent more acetate produced within the M. thermoacetica-Au22 system than the CdS model,” Yang said.

The magic gold nanocluster is the latest discovery coming out of Yang’s lab, which for the past six years has focused on using biohybrid nanostructures to convert CO2 into useful chemicals as part of an ongoing effort to find affordable, abundant resources for renewable fuels, and potential solutions to thwart the effects of climate change.

“Next, we’d like to find a way to reduce costs, improve the lifetimes for these biohybrid systems, and improve quantum efficiency,” Yang said. “By continuing to look at the fundamental aspect of how gold nanoclusters are being photoactivated, and by following the electron transfer process within the CO2 reduction pathway, we hope to find even better solutions.”

Co-authors with Yang are UC Berkeley graduate student Hao Zhang and former postdoctoral fellow Hao Liu, now at Donghua University in Shanghai, China.

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

Bacteria photosensitized by intracellular gold nanoclusters for solar fuel production by Hao Zhang, Hao Liu, Zhiquan Tian, Dylan Lu, Yi Yu, Stefano Cestellos-Blanco, Kelsey K. Sakimoto, & Peidong Yang. Nature Nanotechnologyvolume 13, pages900–905 (2018). DOI: https://doi.org/10.1038/s41565-018-0267-z Published: 01 October 2018

This paper is behind a paywall.

For lovers of animation, the folks at UC Berkeley have produced this piece about the ‘gold-loving’ bacterium,

Frugal science, foldable microscopes, and curiosity: a talk on June 3, 2019 at Simon Fraser University (Burnaby, Canada) … it’s in Metro Vancouver

This is the second frugal science item* I’m publishing today (May 29, 2019) which means that I’ve gone from complete ignorance on the topic to collecting news items about it. Manu Prakash, the developer behind a usable paper microscope than can be folded and kept in your pocket, is going to be giving a talk locally according to a May 28, 2019 announcement (received via email) from Simon Fraser University’s (SFU) Faculty of Science,

On June 3rd [2019], at 7:30 pmManu Prakash from Stanford University will give the Herzberg Public Lecture in conjunction with this year’s Canadian Association of Physicists (CAP) conference that the department is hosting. Dr. Prakash’s lecture is entitled “Frugal Science in the Age of Curiosity”. Tickets are free and can be obtained through Eventbrite: https://t.co/WNrPh9fop5 . 

This presentation will be held at the Shrum Science Centre Chemistry C9001 Lecture Theatre, Burnaby campus (instead of the Diamond Family Auditorium).

There’s a synopsis of the talk on the Herzbergy Public Lecture: Frugal Science in the Age of Curiosity webpage,

Science faces an accessibility challenge. Although information/knowledge is fast becoming available to everyone around the world, the experience of science is significantly limited. One approach to solving this challenge is to democratize access to scientific tools. Manu Prakash believes this can be achieved via “Frugal science”; a philosophy that inspires design, development, and deployment of ultra-affordable yet powerful scientific tools for the masses. Using examples from his own work (Foldscope: one-dollar origami microscope, Paperfuge: a twenty-cent high-speed centrifuge), Dr. Prakash will describe the process of identifying challenges, designing solutions, and deploying these tools globally to enable open ended scientific curiosity/inquiries in communities around the world. By connecting the dots between science education, global health and environmental monitoring, he will explore the role of “simple” tools in advancing access to better human and planetary health in a resource limited world.

If you’re curious there is a Foldscope website where you can find out more and/or get a Foldscope for yourself.

In addition to the talk, there is a day-long workshop for teachers (as part of the 2019 CAP Congress) with Dr. Donna Strickland the University of Waterloo researcher who won the 2018 Nobel Prize for physics. If you want to learn how to make a Foldscope, t here is also a one hour session for which you can register separately from the day-long event,. (I featured Strickland and her win in an October 3, 2018 posting.)

Getting back to the main event. Dr. Prakash’s evening talk, you can register here.

*ETA May 29, 2019 at 1120 hours PDT: My first posting on frugal science is Frugal science: ancient toys for state-of-the-art science. It’s about a 3D printable centrifuge based on a toy known (in English) as a whirligig.

Frugal science: ancient toys for state-of-the-art science

A toy that’s been a plaything for 5,000 years and known as a whirligig (in English, anyway) has inspired a scientific tool for use by field biologists and students interested in creating state-of-the-art experiments. Exciting stuff, eh?

A May 23, 2019 Georgia Tech (Georgia Institute of Technology) news release (also on EurekAlert but published on May 22, 2019) announces this development in ‘frugal science’,

A 5,000-year-old toy still enjoyed by kids today has inspired an inexpensive, hand-powered scientific tool that could not only impact how field biologists conduct their research but also allow high-school students and others with limited resources to realize their own state-of-the-art experiments.

The device, a portable centrifuge for preparing scientific samples including DNA, is reported May 21 [2019] in the journal PLOS Biology. The co-first author of the paper is Gaurav Byagathvalli, a senior at Lambert High School in Georgia. His colleagues are M. Saad Bhamla, an assistant professor at the Georgia Institute of Technology; Soham Sinha, a Georgia Tech undergraduate; Janet Standeven, Byagathvalli’s biology teacher at Lambert; and Aaron F. Pomerantz, a graduate student at the University of California, Berkeley.

“I am exceptionally proud of this paper and will remember it 10, 20, 30 years from now because of the uniquely diverse team we put together,” said Bhamla, who is an assistant professor in Georgia Tech’s School of Chemical and Biomolecular Engineering.

From a Rainforest to a High School

Together the team demonstrated the device, dubbed the 3D-Fuge because it is created through 3D printing, in two separate applications. In a rainforest in Peru the 3D-Fuge was an integral part of a “lab in a backpack” used to identify four previously-unknown plants and insects by sequencing their DNA [deoxyribonucleic acid]. Back in the United States, a slightly different design enabled a new approach to creating living bacterial sensors for the potential detection of disease. That work was conducted at Lambert High School for a synthetic biology competition.

Thanks to social media and a preprint of the PLOS Biology paper on BioRxiv, the 3D-Fuge has already generated interest from around the world, including emails from high-school teachers in Zambia and Kenya. “It’s awesome to see research not just remain isolated to one location but see it spread,” said Byagathvalli. “Through this, we’ve realized how much of an impact simple yet effective tools can have, and hope this technology motivates others to continue along the same path and innovate new solutions to global issues.”

To better share the work, the team has posted the 3D-Fuge designs, videos, and photos online available to anyone.

Frugal Science

One focus of Bhamla’s lab at Georgia Tech is the development of tools for frugal science, or real research that just about anyone can afford. The tools behind state-of-the-art science often cost thousands of dollars that make them inaccessible to those without serious resources.

Centrifuges are a good example.  A small benchtop unit costs between $3,000 and $5,000; larger units cost many times that. Yet the devices are necessary to produce concentrated amounts of, say, genomic materials like DNA. By rapidly spinning samples, they separate materials of interest from biological debris.

The Bhamla team found that the 3D-Fuge works as well as its more expensive cousins, but costs less than $1.

An Ancient Toy

The 3D-Fuge is based on earlier work by Bhamla and colleagues at Stanford University on a simple centrifuge made of paper. The “paperfuge,” in turn, was inspired by a toy composed of string and a button that Bhamla played with as a child. He later discovered that these toys, known as whirligigs, have existed for some 5,000 years.

They consist of a disk – like a button – with two holes, through which is threaded a length of flexible cord whose ends are knotted to create a single loop with the disk in the middle. That simple contraption is then swung with two hands until the button is spinning and whirring at very fast speeds.

The earlier paperfuge uses a disk of paper. To that disk Bhamla glued small plastic tubes filled with a sample. He and colleagues reported that the device did indeed create high-quality samples.

In late 2017 Bhamla was separately approached by the Lambert High team and Pomerantz to see if the paperfuge could be adapted for the larger samples they needed (the paperfuge is limited to small samples of ~1 microliter—or one drop of blood).

Together they came up with the 3D-Fuge, which includes cavities for tubes that can hold some 100 times more of a sample than the paperfuge. The team developed two equally effective designs: one for field biology (led by Pomerantz) and the other for the high-school’s synthetic biology project (led by Byagathvalli).

Bhamla notes that the 3D-Fuge has some limitations. For example, it can only process a few samples at a time (some applications require thousands of samples). Further, because it’s 10 times heavier than the paperfuge, it can’t reach the same speeds or produce the same forces of that device. That said, it still weighs only 20 grams, slightly less than a AA battery.

“But it works,” said Bhamla. “All you need is an [appropriate] application and some creativity.”

Here are a couple of images showing the 3D-Fuge in action,

Using the 3D-Fuge Courtesy: Georgia Tech
Sample vial in 3D-Fuge Courtesy: Georgia Tech

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

A 3D-printed hand-powered centrifuge for molecular biology by Gaurav Byagathvalli, Aaron Pomerantz, Soham Sinha, Janet Standeven, M. Saad Bhamla. PLOS Biology DOI: https://doi.org/10.1371/journal.pbio.3000251 Published: May 21, 2019

As always with a Public Library of Science (PLOS) publication, this paper is open access.

Fake graphene

Michael Berger’s October 9, 2018 Nanowerk Spotlight article about graphene brings to light a problem, which in hindsight seems obvious, fake graphene (Note: Links have been removed),

Peter Bøggild over at DTU [Technical University of Denmark] just published an interesting opinion piece in Nature titled “The war on fake graphene”.

The piece refers to a paper published in Advanced Materials (“The Worldwide Graphene Flake Production”) that studied graphene purchased from 60 producers around the world.

The study’s [“The Worldwide Graphene Flake Production”] findings show unequivocally “that the quality of the graphene produced in the world today is rather poor, not optimal for most applications, and most companies are producing graphite microplatelets. This is possibly the main reason for the slow development of graphene applications, which usually require a customized solution in terms of graphene properties.”

A conclusion that sounds even more damming is that “our extensive studies of graphene production worldwide indicate that there is almost no high quality graphene, as defined by ISO [International Organization for Standardization], in the market yet.”

The team also points out that a large number of the samples on the market labelled as graphene are actually graphene oxide and reduced graphene oxide. Furthermore, carbon content analysis shows that in many cases there is substantial contamination of the samples and a large number of companies produce material a with low carbon content. Contamination has many possible sources but most likely, it arises from the chemicals used in the processes.

Peter Bøggild’s October 8, 2018 opinion piece in Nature

Graphite is composed of layers of carbon atoms just a single atom in thickness, known as graphene sheets, to which it owes many of its remarkable properties. When the thickness of graphite flakes is reduced to just a few graphene layers, some of the material’s technologically most important characteristics are greatly enhanced — such as the total surface area per gram, and the mechanical flexibility of the individual flakes. In other words, graphene is more than just thin graphite. Unfortunately, it seems that many graphene producers either do not know or do not care about this. …

Imagine a world in which antibiotics could be sold by anybody, and were not subject to quality standards and regulations. Many people would be afraid to use them because of the potential side effects, or because they had no faith that they would work, with potentially fatal consequences. For emerging nanomaterials such as graphene, a lack of standards is creating a situation that, although not deadly, is similarly unacceptable.

It seems that the high-profile scientific discoveries, technical breakthroughs and heavy investment in graphene have created a Wild West for business opportunists: the study shows that some producers are labelling black powders that mostly contain cheap graphite as graphene, and selling them for top dollar. The problem is exacerbated because the entry barrier to becoming a graphene provider is exceptionally low — anyone can buy bulk graphite, grind it to powder and make a website to sell it on.

Nevertheless, the work [“The Worldwide Graphene Flake Production”] is a timely and ambitious example of the rigorous mindset needed to make rapid progress, not just in graphene research, but in work on any nanomaterial entering the market. To put it bluntly, there can be no quality without quality control.

Here are links to and citations for the study providing the basis for both Berger’s Spotlight article and Bøggild’s opinion piece,

The Worldwide Graphene Flake Production by Alan P. Kauling, Andressa T. Seefeldt, Diego P. Pisoni, Roshini C. Pradeep, Ricardo Bentini, Ricardo V. B. Oliveira, Konstantin S. Novoselov [emphasis mine], Antonio H. Castro Neto. Advanced Materials Volume 30, Issue 44 November 2, 2018 1803784 https://doi.org/10.1002/adma.201803784

The study which includes Konstantin Novoselov, a Nobel prize winner for his and Andre Geim’s work at the University of Manchester where they first isolated graphene, is behind a paywall.