Double-walled carbon nanotubes have superior electrical properties?

A March 27, 2020 news item on Nanowerk suggests that double-walled carbon nanotubes (DWCNTs) may offer some advantages over single-walled carbon nanotubes (SWCNTs), NOTE: A link has been removed,

One nanotube could be great for electronics applications, but there’s new evidence that two could be tops.

Rice University engineers already knew that size matters when using single-walled carbon nanotubes for their electrical properties. But until now, nobody had studied how electrons act when confronted with the Russian doll-like structure of multiwalled tubes.

There’s a diagram representing the work,

Caption: Rice University theorists have calculated flexoelectric effects in double-walled carbon nanotubes. The electrical potential (P) of atoms on either side of a graphene sheet (top) are identical, but not when the sheet is curved into a nanotube. Double-walled nanotubes (bottom) show unique effects as band gaps in inner and outer tubes are staggered. Credit: Yakobson Research Group/Rice University

A March 27, 2020 Rice University news release (also on EurekAlert), which originated the news item, delves further (NOTE: Links have been removed),

The Rice lab of materials theorist Boris Yakobson has now calculated the impact of curvature of semiconducting double-wall carbon nanotubes on their flexoelectric voltage, a measure of electrical imbalance between the nanotube’s inner and outer walls.

This affects how suitable nested nanotube pairs may be for nanoelectronics applications, especially photovoltaics.

The theoretical research by Yakobson’s Brown School of Engineering group appears in the American Chemical Society journal Nano Letters.

In an 2002 study, Yakobson and his Rice colleagues had revealed how charge transfer, the difference between positive and negative poles that allows voltage to exist between one and the other, scales linearly to the curvature of the nanotube wall. The width of the tube dictates curvature, and the lab found that the thinner the nanotube (and thus larger the curvature), the greater the potential voltage.

When carbon atoms form flat graphene, the charge density of the atoms on either side of the plane are identical, Yakobson said. Curving the graphene sheet into a tube breaks that symmetry, changing the balance.

That creates a flexoelectric local dipole in the direction of, and proportional to, the curvature, according to the researchers, who noted that the flexoelectricity of 2D carbon “is a remarkable but also fairly subtle effect.”

But more than one wall greatly complicates the balance, altering the distribution of electrons. In double-walled nanotubes, the curvature of the inner and outer tubes differ, giving each a distinct band gap. Additionally, the models showed the flexoelectric voltage of the outer wall shifts the band gap of the inner wall, creating a staggered band alignment in the nested system.

“The novelty is that the inserted tube, the ‘baby’ (inside) matryoshka has all of its quantum energy levels shifted because of the voltage created by exterior nanotube,” Yakobson said. The interplay of different curvatures, he said, causes a straddling-to-staggered band gap transition that takes place at an estimated critical diameter of about 2.4 nanometers.

“This is a huge advantage for solar cells, essentially a prerequisite for separating positive and negative charges to create a current,” Yakobson said. “When light is absorbed, an electron always jumps from the top of an occupied valence band (leaving a ‘plus’ hole behind) to the lowest state of empty conductance band.

“But in a staggered configuration they happen to be in different tubes, or layers,” he said. “The ‘plus’ and ‘minus’ get separated between the tubes and can flow away by generating current in a circuit.”

The team’s calculations also showed that modifying the nanotubes’ surfaces with either positive or negative atoms could create “substantial voltages of either sign” up to three volts. “Although functionalization could strongly perturb the electronic properties of nanotubes, it may be a very powerful way of inducing voltage for certain applications,” the researchers wrote.

The team suggested its findings may apply to other types of nanotubes, including boron nitride and molybdenum disulfide, on their own or as hybrids with carbon nanotubes.

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

Flexoelectricity and charge separation in carbon nanotubes by Vasilii I. Artyukhov, Sunny Gupta, Alex Kutana, Boris I. Yakobson. Nano Lett. 2020, XXXX, XXX, XXX-XXX DOI: https://doi.org/10.1021/acs.nanolett.9b05345 [Online] Publication Date:March 10, 2020 Copyright © 2020 American Chemical Society

This paper is behind a paywall.

Slippery toilet coating could save water

On a practical level, it’s becoming clear that we need to become more thoughtful about our use of water. We here in Canada tend to take our water for granted, as if we have an inexhaustible supply. According to this August 21, 2008 CBC (Canadian Broadcasting Corporation) online news item, that’s not the case,

Canada’s stores of fresh water are not as plentiful as once thought, and threaten to pinch the economy and pit provinces against each other, a federal document says.

An internal report drafted last December [2007] by Environment Canada warns that climate change and a growing population will further drain resources.

“We can no longer take our extensive water supplies for granted,” says the report, titled A Federal Perspective on Water Quantity Issues.

The Canadian Press obtained the 21-page draft report under the Access to Information Act.

It suggests the federal government take a more hands-on role in managing the country’s water, which is now largely done by the provinces. Ottawa still manages most of the fresh water in the North through water boards.

The Conservatives promised a national water strategy in last fall’s throne speech but have been criticized since for announcing only piecemeal projects.

The Tories, like the previous Liberal government, are also behind in publishing annual reports required by law that show how water supplies are used and maintained.

The last assessment posted on Environment Canada’s website is from 2005-06.

The internal draft report says the government currently does not know enough about the country’s water to properly manage it.

‘This is not a crisis yet. Why would we expect any government, regardless of political leaning or level, to do anything about it?’

“Canada lacks sound information at a national scale on the major uses and user[s] of water,” it says.

“National forecasting of water availability has never been done because traditionally our use of the resource was thought to be unlimited.”

Canada has a fifth of the world’s supply of fresh water, but only seven per cent of it is renewable. The rest comes from ice-age glaciers and underground aquifers.

One per cent of Canada’s total water supply is renewed each year by precipitation, the report says.

Moreover, government data on the country’s groundwater reserves is deemed “sparse and often inadequate.”

That’s in contrast to the United States, which has spent more than a decade mapping its underground water reserves. Canada shares aquifers with the U.S., and the report says: “Our lack of data places Canada at strategic disadvantage for bilateral negotiations with the U.S.”

The most recent update I can find is Ivan Semeniuk’s June 11, 2017 article for the Globe and Mail tilted: Charting Canada’s troubled waters: Where the danger lies for watersheds across the country,

A comprehensive review [World Wildlife Federation: a national assessment of of Canada’s freshwater Watershed Reports; 2017] freshwater ecosystems reveals rising threats from pollution, overuse, invasive species and climate change among other problems. Yet, the biggest threat of all may be a lack of information that hinders effective regulation, Ivan Semeniuk reports. …

Some of that information may be out of date.

Getting back on topic, here’s one possible solution to better managing our use of water.

Toilet coating

A November 18, 2019 news item on phys.org announces research that could save water,

Every day, more than 141 billion liters of water are used solely to flush toilets. With millions of global citizens experiencing water scarcity, what if that amount could be reduced by 50%?

The possibility may exist through research conducted at Penn State, released today (Nov. 18) in Nature Sustainability.

“Our team has developed a robust bio-inspired, liquid, sludge- and bacteria-repellent coating that can essentially make a toilet self-cleaning,” said Tak-Sing Wong, Wormley Early Career Professor of Engineering and associate professor of mechanical engineering and biomedical engineering.

Penn State researchers have developed a method that dramatically reduces the amount of water needed to flush a conventional toilet, which usually requires 6 liters. Image: Wong Laboratory for Nature Inspired Engineering

A November 18, 2019 Pennsylvania State University news release (also on EurekAlert,) which originated the news item, describes the research in more detail,

In the Wong Laboratory for Nature Inspired Engineering, housed within the Department of Mechanical Engineering and the Materials Research Institute, researchers have developed a method that dramatically reduces the amount of water needed to flush a conventional toilet, which usually requires 6 liters.

Co-developed by Jing Wang, a doctoral graduate from Wong’s lab, the liquid-entrenched smooth surface (LESS) coating is a two-step spray that, among other applications, can be applied to a ceramic toilet bowl. The first spray, created from molecularly grafted polymers, is the initial step in building an extremely smooth and liquid-repellent foundation.

“When it dries, the first spray grows molecules that look like little hairs, with a diameter of about 1,000,000 times thinner than a human’s,” Wang said.

While this first application creates an extremely smooth surface as is, the second spray infuses a thin layer of lubricant around those nanoscopic “hairs” to create a super-slippery surface.

“When we put that coating on a toilet in the lab and dump synthetic fecal matter on it, it (the synthetic fecal matter) just completely slides down and nothing sticks to it (the toilet),” Wang said.

With this novel slippery surface, the toilets can effectively clean residue from inside the bowl and dispose of the waste with only a fraction of the water previously needed. The researchers also predict the coating could last for about 500 flushes in a conventional toilet before a reapplication of the lubricant layer is needed.

While other liquid-infused slippery surfaces can take hours to cure, the LESS two-step coating takes less than five minutes. The researcher’s experiments also found the surface effectively repelled bacteria, particularly ones that spread infectious diseases and unpleasant odors.

If it were widely adopted in the United States, it could direct critical resources toward other important activities, to drought-stricken areas or to regions experiencing chronic water scarcity, said the researchers.

Driven by these humanitarian solutions, the researchers also hope their work can make an impact in the developing world. The technology could be used within waterless toilets, which are used extensively around the world.

“Poop sticking to the toilet is not only unpleasant to users, but it also presents serious health concerns,” Wong said.

However, if a waterless toilet or urinal used the LESS coating, the team predicts these types of fixtures would be more appealing and safer for widespread use.

To address these issues in both the United States and around the world, Wong and his collaborators, Wang, Birgitt Boschitsch, and Nan Sun, all mechanical engineering alumni, began a start-up venture.

With support from the Ben Franklin Technology Partners’ TechCelerator, the National Science Foundation, the Department of Energy, the Office of Naval Research, the Rice Business Plan Competition and Y-Combinator, their company, spotLESS Materials, is already bringing the LESS coating to market.

“Our goal is to bring impactful technology to the market so everyone can benefit,” Wong said. “To maximize the impact of our coating technology, we need to get it out of the lab.”

Looking forward, the team hopes spotLESS Materials will play a role in sustaining the world’s water resources and continue expanding the reach of their technology.

“As a researcher in an academic setting, my goal is to invent things that everyone can benefit from,” Wong said. “As a Penn Stater, I see this culture being amplified through entrepreneurship, and I’m excited to contribute.”

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

Viscoelastic solid-repellent coatings for extreme water saving and global sanitation by Jing Wang, Lin Wang, Nan Sun, Ross Tierney, Hui Li, Margo Corsetti, Leon Williams, Pak Kin Wong & Tak-Sing Wong. Nature Sustainability (2019) DOI: https://doi.org/10.1038/s41893-019-0421-0 Published 18 November 2019

This paper is behind a paywall. However, the researchers have made a brief video available,

There you have it. One random thought, that toilet image reminded me of the controversy over Marcel Duchamp, the Fountain, and who actually submitted a urinal for consideration as a piece of art (Jan. 23, 2019 posting). Hint: Some believe it was Baroness Elsa von Freytag-Loringhoven.

Are nano electronics as good as gold?

“As good as gold” was a behavioural goal when I was a child. It turns out, the same can be said of gold in electronic devices according to the headline for a March 26, 2020 news item on Nanowerk (Note: Links have been removed),

As electronics shrink to nanoscale, will they still be good as gold?

Deep inside computer chips, tiny wires made of gold and other conductive metals carry the electricity used to process data.

But as these interconnected circuits shrink to nanoscale, engineers worry that pressure, such as that caused by thermal expansion when current flows through these wires, might cause gold to behave more like a liquid than a solid, making nanoelectronics unreliable. That, in turn, could force chip designers to hunt for new materials to make these critical wires.

But according to a new paper in Physical Review Letters (“Nucleation of Dislocations in 3.9 nm Nanocrystals at High Pressure”), chip designers can rest easy. “Gold still behaves like a solid at these small scales,” says Stanford mechanical engineer Wendy Gu, who led a team that figured out how to pressurize gold particles just 4 nanometers in length — the smallest particles ever measured — to assess whether current flows might cause the metal’s atomic structure to collapse.

I have seen the issue about gold as a metal or liquid before but I can’t find it here (search engines, sigh). However, I found this somewhat related story from almost five years ago. In my April 14, 2015 posting (Gold atoms: sometimes they’re a metal and sometimes they’re a molecule), there was news that the number of gold atoms present means the difference between being a metal and being a molecule .This could have implications as circuit elements (which include some gold in their fabrication) shrink down past a certain point.

A March 24, 2020 Stanford University news release (also on Eurekalert but published on March 25, 2020) by Andrew Myers, which originated the news item, provides details about research designed to investigate a similar question, i.e, can we used gold as we shrink the scale?*,

To conduct the experiment, Gu’s team first had to devise a way put tiny gold particles under extreme pressure, while simultaneously measuring how much that pressure damaged gold’s atomic structure.

To solve the first problem, they turned to the field of high-pressure physics to borrow a device known as a diamond anvil cell. As the name implies, both hammer and anvil are diamonds that are used to compress the gold. As Gu explained, a nanoparticle of gold is built like a skyscraper with atoms forming a crystalline lattice of neat rows and columns. She knew that pressure from the anvil would dislodge some atoms from the crystal and create tiny defects in the gold.

The next challenge was to detect these defects in nanoscale gold. The scientists shined X-rays through the diamond onto the gold. Defects in the crystal caused the X-rays to reflect at different angles than they would on uncompressed gold. By measuring variations in the angles at which the X-rays bounced off the particles before and after pressure was applied, the team was able to tell whether the particles retained the deformations or reverted to their original state when pressure was lifted.

In practical terms, her findings mean that chipmakers can know with certainty that they’ll be able to design stable nanodevices using gold — a material they have known and trusted for decades — for years to come.

“For the foreseeable future, gold’s luster will not fade,” Gu says.

*The 2015 research measured the gold nanoclusters by the number of atoms within the cluster with the changes occurring at some where between 102 atoms and 144 atoms. This 2020 work measures the amount of gold by nanometers as in 3.9 nm gold nanocrystals . So, how many gold atoms in a nanometer? Cathy Murphy provides the answer and the way to calculate it for yourself in a July 26, 2016 posting on the Sustainable Nano blog ( a blog by the Center for Sustainable Nanotechnology),

Two years ago, I wrote a blog post called Two Ways to Make Nanoparticles, describing the difference between top-down and bottom-up methods for making nanoparticles. In the post I commented, “we can estimate, knowing how gold atoms pack into crystals, that there are about 2000 gold atoms in one 4 nm diameter gold nanoparticle.” Recently, a Sustainable Nano reader wrote in to ask about how this calculation is done. It’s a great question!

So, a 3.9 nm gold nanocrystal contains approximately 2000 gold atoms. (If you have time, do read Murphy’s description of how to determine the number of gold atoms in a gold nanoparticle.) So, this research does not answer the question posed by the 2015 research.

It may take years before researchers can devise tests for gold nanoclusters consisting of 102 atoms as opposed to nanoparticles consisting of 2000 atoms. In the meantime, here’s a link to and a citation for the latest on how gold reacts as we shrink the size of our electronics,

Nucleation of Dislocations in 3.9 nm Nanocrystals at High Pressure by Abhinav Parakh, Sangryun Lee, K. Anika Harkins, Mehrdad T. Kiani, David Doan, Martin Kunz, Andrew Doran, Lindsey A. Hanson, Seunghwa Ryu, and X. Wendy Gu. Phys. Rev. Lett. 124, 106104 DOI:https://doi.org/10.1103/PhysRevLett.124.106104 Published 13 March 2020 © 2020 American Physical Society

This paper is behind a paywall.

Some amusements in the time of COVID-19

Gold stars for everyone who recognized the loose paraphrasing of the title, Love in the Time of Cholera, for Gabrial Garcia Marquez’s 1985 novel.

I wrote my headline and first paragraph yesterday and found this in my email box this morning, from a March 25, 2020 University of British Columbia news release, which compares times, diseases, and scares of the past with today’s COVID-19 (Perhaps politicians and others could read this piece and stop using the word ‘unprecedented’ when discussing COVID-19?),

How globalization stoked fear of disease during the Romantic era

In the late 18th and early 19th centuries, the word “communication” had several meanings. People used it to talk about both media and the spread of disease, as we do today, but also to describe transport—via carriages, canals and shipping.

Miranda Burgess, an associate professor in UBC’s English department, is working on a book called Romantic Transport that covers these forms of communication in the Romantic era and invites some interesting comparisons to what the world is going through today.

We spoke with her about the project.

What is your book about?

It’s about global infrastructure at the dawn of globalization—in particular the extension of ocean navigation through man-made inland waterways like canals and ship’s canals. These canals of the late 18th and early 19th century were like today’s airline routes, in that they brought together places that were formerly understood as far apart, and shrunk time because they made it faster to get from one place to another.

This book is about that history, about the fears that ordinary people felt in response to these modernizations, and about the way early 19th-century poets and novelists expressed and responded to those fears.

What connections did those writers make between transportation and disease?

In the 1810s, they don’t have germ theory yet, so there’s all kinds of speculation about how disease happens. Works of tropical medicine, which is rising as a discipline, liken the human body to the surface of the earth. They talk about nerves as canals that convey information from the surface to the depths, and the idea that somehow disease spreads along those pathways.

When the canals were being built, some writers opposed them on the grounds that they could bring “strangers” through the heart of the city, and that standing water would become a breeding ground for disease. Now we worry about people bringing disease on airplanes. It’s very similar to that.

What was the COVID-19 of that time?

Probably epidemic cholera [emphasis mine], from about the 1820s onward. The Quarterly Review, a journal that novelist Walter Scott was involved in editing, ran long articles that sought to trace the map of cholera along rivers from South Asia, to Southeast Asia, across Europe and finally to Britain. And in the way that its spread is described, many of the same fears that people are evincing now about COVID-19 were visible then, like the fear of clothes. Is it in your clothes? Do we have to burn our clothes? People were concerned.

What other comparisons can be drawn between those times and what is going on now?

Now we worry about the internet and “fake news.” In the 19th century, they worried about what William Wordsworth called “the rapid communication of intelligence,” which was the daily newspaper. Not everybody had access to newspapers, but each newspaper was read by multiple families and newspapers were available in taverns and coffee shops. So if you were male and literate, you had access to a newspaper, and quite a lot of women did, too.

Paper was made out of rags—discarded underwear. Because of the French Revolution and Napoleonic Wars that followed, France blockaded Britain’s coast and there was a desperate shortage of rags to make paper, which had formerly come from Europe. And so Britain started to import rags from the Caribbean that had been worn by enslaved people.

Papers of the time are full of descriptions of the high cost of rags, how they’re getting their rags from prisons, from prisoners’ underwear, and fear about the kinds of sweat and germs that would have been harboured in those rags—and also discussions of scarcity, as people stole and hoarded those rags. It rings very well with what the internet is telling us now about a bunch of things around COVID-19.

Plus ça change, n’est-ce pas?

And now for something completely different

Kudos to all who recognized the Monty Python reference. Now, onto the frogfish,

Thank you to the Monterey Bay Aquarium (in California, US).

A March 22, 2020 University of Washington (state) news release features an interview with the author of a new book on frogfishes,

Any old fish can swim. But what fish can walk, scoot, clamber over rocks, change color or pattern and even fight? That would be the frogfish.

The latest book by Ted Pietsch, UW professor emeritus of aquatic and fishery sciences, explores the lives and habits of these unusual marine shorefishes. “Frogfishes: Biodiversity, Zoogeography, and Behavioral Ecology” was published in March [2020] by Johns Hopkins University Press.

Pietsch, who is also curator emeritus of fishes at the Burke Museum of Natural History and Culture, has published over 200 articles and a dozen books on the biology and behavior of marine fishes. He wrote this book with Rachel J. Arnold, a faculty member at Northwest Indian College in Bellingham and its Salish Sea Research Center.

These walking fishes have stepped into the spotlight lately, with interest growing in recent decades. And though these predatory fishes “will almost certainly devour anything else that moves in a home aquarium,” Pietsch writes, “a cadre of frogfish aficionados around the world has grown within the dive community and among aquarists.” In fact, Pietsch said, there are three frogfish public groups on Facebook, with more than 6,000 members.

First, what is a frogfish?

Ted Pietsch: A member of a family of bony fishes, containing 52 species, all of which are highly camouflaged and whose feeding strategy consists of mimicking the immobile, inert, and benign appearance of a sponge or an algae-encrusted rock, while wiggling a highly conspicuous lure to attract prey.

This is a fish that “walks” and “hops” across the sea bottom, and clambers about over rocks and coral like a four-legged terrestrial animal but, at the same time, can jet-propel itself through open water. Some lay their eggs encapsulated in a complex, floating, mucus mass, called an “egg raft,” while some employ elaborate forms of parental care, carrying their eggs around until they hatch.

They are among the most colorful of nature’s productions, existing in nearly every imaginable color and color pattern, with an ability to completely alter their color and pattern in a matter of days or seconds. All these attributes combined make them one of the most intriguing groups of aquatic vertebrates for the aquarist, diver, and underwater photographer as well as the professional zoologist.

I couldn’t resist the ‘frog’ reference and I’m glad since this is a good read with a number of fascinating photographs and illustrations.,

An illustration of the frogfish Antennarius pictus, published by George Shaw in 1794. From a new book by Ted Pietsch, UW professor of emeritus of aquatic and fishery sciences. Courtesy: University of Washington (state)

h/t phys.org March 24, 2020 news item

Building with bacteria

A block of sand particles held together by living cells. Credit: The University of Colorado Boulder College of Engineering and Applied Science

A March 24, 2020 news item on phys.org features the future of building construction as perceived by synthetic biologists,

Buildings are not unlike a human body. They have bones and skin; they breathe. Electrified, they consume energy, regulate temperature and generate waste. Buildings are organisms—albeit inanimate ones.

But what if buildings—walls, roofs, floors, windows—were actually alive—grown, maintained and healed by living materials? Imagine architects using genetic tools that encode the architecture of a building right into the DNA of organisms, which then grow buildings that self-repair, interact with their inhabitants and adapt to the environment.

A March 23, 2020 essay by Wil Srubar (Professor of Architectural Engineering and Materials Science, University of Colorado Boulder), which originated the news item, provides more insight,

Living architecture is moving from the realm of science fiction into the laboratory as interdisciplinary teams of researchers turn living cells into microscopic factories. At the University of Colorado Boulder, I lead the Living Materials Laboratory. Together with collaborators in biochemistry, microbiology, materials science and structural engineering, we use synthetic biology toolkits to engineer bacteria to create useful minerals and polymers and form them into living building blocks that could, one day, bring buildings to life.

In one study published in Scientific Reports, my colleagues and I genetically programmed E. coli to create limestone particles with different shapes, sizes, stiffnesses and toughness. In another study, we showed that E. coli can be genetically programmed to produce styrene – the chemical used to make polystyrene foam, commonly known as Styrofoam.

Green cells for green building

In our most recent work, published in Matter, we used photosynthetic cyanobacteria to help us grow a structural building material – and we kept it alive. Similar to algae, cyanobacteria are green microorganisms found throughout the environment but best known for growing on the walls in your fish tank. Instead of emitting CO2, cyanobacteria use CO2 and sunlight to grow and, in the right conditions, create a biocement, which we used to help us bind sand particles together to make a living brick.

By keeping the cyanobacteria alive, we were able to manufacture building materials exponentially. We took one living brick, split it in half and grew two full bricks from the halves. The two full bricks grew into four, and four grew into eight. Instead of creating one brick at a time, we harnessed the exponential growth of bacteria to grow many bricks at once – demonstrating a brand new method of manufacturing materials.

Researchers have only scratched the surface of the potential of engineered living materials. Other organisms could impart other living functions to material building blocks. For example, different bacteria could produce materials that heal themselves, sense and respond to external stimuli like pressure and temperature, or even light up. If nature can do it, living materials can be engineered to do it, too.

It also take less energy to produce living buildings than standard ones. Making and transporting today’s building materials uses a lot of energy and emits a lot of CO2. For example, limestone is burned to make cement for concrete. Metals and sand are mined and melted to make steel and glass. The manufacture, transport and assembly of building materials account for 11% of global CO2 emissions. Cement production alone accounts for 8%. In contrast, some living materials, like our cyanobacteria bricks, could actually sequester CO2.

The field of engineered living materials is in its infancy, and further research and development is needed to bridge the gap between laboratory research and commercial availability. Challenges include cost, testing, certification and scaling up production. Consumer acceptance is another issue. For example, the construction industry has a negative perception of living organisms. Think mold, mildew, spiders, ants and termites. We’re hoping to shift that perception. Researchers working on living materials also need to address concerns about safety and biocontamination.

The [US] National Science Foundation recently named engineered living materials one of the country’s key research priorities. Synthetic biology and engineered living materials will play a critical role in tackling the challenges humans will face in the 2020s and beyond: climate change, disaster resilience, aging and overburdened infrastructure, and space exploration.

If you have time and interest, this is fascinating. Strubar is a little exuberant and, at this point, I welcome it.

Fitness

The Lithuanians are here for us. Scientists from the Kaunas University of Technology have just published a paper on better exercises for lower back pain in our increasingly sedentary times, from a March 23, 2020 Kaunas University of Technology press release (also on EurekAlert) Note: There are a few minor grammatical issues,

With the significant part of the global population forced to work from home, the occurrence of lower back pain may increase. Lithuanian scientists have devised a spinal stabilisation exercise programme for managing lower back pain for people who perform a sedentary job. After testing the programme with 70 volunteers, the researchers have found that the exercises are not only efficient in diminishing the non-specific lower back pain, but their effect lasts 3 times longer than that of a usual muscle strengthening exercise programme.

According to the World Health Organisation, lower back pain is among the top 10 diseases and injuries that are decreasing the quality of life across the global population. It is estimated that non-specific low back pain is experienced by 60% to 70% of people in industrialised societies. Moreover, it is the leading cause of activity limitation and work absence throughout much of the world. For example, in the United Kingdom, low back pain causes more than 100 million workdays lost per year, in the United States – an estimated 149 million.

Chronic lower back pain, which starts from long-term irritation or nerve injury affects the emotions of the afflicted. Anxiety, bad mood and even depression, also the malfunctioning of the other bodily systems – nausea, tachycardia, elevated arterial blood pressure – are among the conditions, which may be caused by lower back pain.

During the coronavirus disease (COVID-19) outbreak, with a significant part of the global population working from home and not always having a properly designed office space, the occurrence of lower back pain may increase.

“Lower back pain is reaching epidemic proportions. Although it is usually clear what is causing the pain and its chronic nature, people tend to ignore these circumstances and are not willing to change their lifestyle. Lower back pain usually comes away itself, however, the chances of the recurring pain are very high”, says Dr Irina Klizienė, a researcher at Kaunas University of Technology (KTU) Faculty of Social Sciences, Humanities and Arts.

Dr Klizienė, together with colleagues from KTU and from Lithuanian Sports University has designed a set of stabilisation exercises aimed at strengthening the muscles which support the spine at the lower back, i.e. lumbar area. The exercise programme is based on Pilates methodology.

According to Dr Klizienė, the stability of lumbar segments is an essential element of body biomechanics. Previous research evidence shows that in order to avoid the lower back pain it is crucial to strengthen the deep muscles, which are stabilising the lumbar area of the spine. One of these muscles is multifidus muscle.

“Human central nervous system is using several strategies, such as preparing for keeping the posture, preliminary adjustment to the posture, correcting the mistakes of the posture, which need to be rectified by specific stabilising exercises. Our aim was to design a set of exercises for this purpose”, explains Dr Klizienė.

The programme, designed by Dr Klizienė and her colleagues is comprised of static and dynamic exercises, which train the muscle strength and endurance. The static positions are to be held from 6 to 20 seconds; each exercise to be repeated 8 to 16 times.

Caption: The static positions are to be held from 6 to 20 seconds; each exercise to be repeated 8 to 16 times. Credit: KTU

The previous set is a little puzzling but perhaps you’ll find these ones below easier to follow,

Caption: The exercises are aimed at strengthening the muscles which support the spine at the lower back. Credit: KTU

I think more pictures of intervening moves would have been useful. Now. getting back to the press release,

In order to check the efficiency of the programme, 70 female volunteers were randomly enrolled either to the lumbar stabilisation exercise programme or to a usual muscle strengthening exercise programme. Both groups were exercising twice a week for 45 minutes for 20 weeks. During the experiment, ultrasound scanning of the muscles was carried out.

As soon as 4 weeks in lumbar stabilisation programme, it was observed that the cross-section area of the multifidus muscle of the subjects of the stabilisation group has increased; after completing the programme, this increase was statistically significant (p < 0,05). This change was not observed in the strengthening group.

Moreover, although both sets of exercises were efficient in eliminating lower back pain and strengthening the muscles of the lower back area, the effect of stabilisation exercises lasted 3 times longer – 12 weeks after the completion of the stabilisation programme against 4 weeks after the completion of the muscle strengthening programme.

“There are only a handful of studies, which have directly compared the efficiency of stabilisation exercises against other exercises in eliminating lower back pain”, says Dr Klizienė, “however, there are studies proving that after a year, lower back pain returned only to 30% of people who have completed a stabilisation exercise programme, and to 84% of people who haven’t taken these exercises. After three years these proportions are 35% and 75%.”

According to her, research shows that the spine stabilisation exercises are more efficient than medical intervention or usual physical activities in curing the lower back pain and avoiding the recurrence of the symptoms in the future.

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

Effect of different exercise programs on non-specific chronic low back pain and disability in people who perform sedentary work by Saule Sipavicienea, Irina Klizieneb. Clinical Biomechanics March 2020 Volume 73, Pages 17–27 DOI: https://doi.org/10.1016/j.clinbiomech.2019.12.028

This paper is behind a paywall.

ISEA (International Symposium on Electronic Arts) 2020: Why Sentience? rescheduled to October 2020 in Montréal, Québec

Mentioned here twice (in a November 29, 2019 posting about the call for proposals and in a March 4, 2020 posting about the preliminary programme), the 2020 International Symposium on Electronic Arts has been postponed, from a March 23, 2020 announcement received via email,

POSTPONEMENT NOTICE – ISEA2020
New Dates: October 13 to 18, 2020

Montreal, March 23, 2020 — With the COVID-19 pandemic, the world is facing an extraordinary situation. Following the measures announced by the Government of Quebec and the Government of Canada, in a concerted decision with its partners and collaborators, Montreal Digital Spring (Printemps numérique) has decided to postpone ISEA2020: WHY SENTIENCE? We are looking forward to seeing you in Montreal, October 13 to 18 2020!

Our priorities are public health and high-quality programming, and we will work hard during the spring and summer to ensure that the ISEA community enjoys a memorable symposium! We thank you for your understanding.

TICKETS

Any purchases already made will be automatically transferred to the new dates. The new deadline for Early Bird registration, for presenters to upload camera-ready papers and to fill in the Zone Festival form is May 1st, 2020 at 11:59 pm (GMT-5).

The answers to most of your questions can be found in the FAQ. If you have a specific question, contact us at the following emails: 

Regarding academic papers, panels, institutional presentations and artist talks, contact: isea.academic@printempsnumerique.ca

For artworks, contact: isea.artistic@printempsnumerique.ca

For workshops, contact: sylvaine@printempsnumerique.ca

For general public, contact: ISEA2020@printempsnumerique.ca

See you in Montreal in October!

There you have it.

In the future your clothing may be a health monitor

It’s not ready for the COVID-19 pandemic but if I understand it properly, wearing this clothing will be a little like wearing a thermometer and that could be very useful. A March 4, 2020 news item on Nanowerk announces the research (Note: A link has been removed),

Researchers have reported a new material, pliable enough to be woven into fabric but imbued with sensing capabilities that can serve as an early warning system for injury or illness.

The material, described in a paper published by ACS Applied Nano Materials (“Poly(octadecyl acrylate)-Grafted Multiwalled Carbon Nanotube Composites for Wearable Temperature Sensors”), involves the use of carbon nanotubes and is capable of sensing slight changes in body temperature while maintaining a pliable disordered structure – as opposed to a rigid crystalline structure – making it a good candidate for reusable or disposable wearable human body temperature sensors. Changes in body heat change the electrical resistance, alerting someone monitoring that change to the potential need for intervention.

I think this is an artistic rendering of the research,

Caption: Researchers have reported a new material, pliable enough to be woven into fabric but imbued with sensing capabilities that could serve as an early warning system for injury or illness. Credit: University of Houston

A March 4, 2020 University of Houston (Texas, US) news release (also on EurekAlert) by Jeannie Kever, which originated the news item, describes the work in more detail,

“Your body can tell you something is wrong before it becomes obvious,” said Seamus Curran, a physics professor at the University of Houston and co-author on the paper. Possible applications range from detecting dehydration in an ultra-marathoner to the beginnings of a pressure sore in a nursing home patient.

The researchers said it is also cost-effective because the raw materials required are used in relatively low concentrations.

The discovery builds on work Curran and fellow researchers Kang-Shyang Liao and Alexander J. Wang began nearly a decade ago, when they developed a hydrophobic nanocoating for cloth, which they envisioned as a protective coating for clothing, carpeting and other fiber-based materials.

Wang is now a Ph.D. student at Technological University Dublin, currently working with Curran at UH, and is corresponding author for the paper. In addition to Curran and Liao, other researchers involved include Surendra Maharjan, Brian P. McElhenny, Ram Neupane, Zhuan Zhu, Shuo Chen, Oomman K. Varghese and Jiming Bao, all of UH; Kourtney D. Wright and Andrew R. Barron of Rice University, and Eoghan P. Dillon of Analysis Instruments in Santa Barbara.

The material, created using poly(octadecyl acrylate)-grafted multiwalled carbon nanotubes, is technically known as a nanocarbon-based disordered, conductive, polymeric nanocomposite, or DCPN, a class of materials increasingly used in materials science. But most DCPN materials are poor electroconductors, making them unsuitable for use in wearable technologies that require the material to detect slight changes in temperature.

The new material was produced using a technique called RAFT-polymerization, Wang said, a critical step that allows the attached polymer to be electronically and phononically coupled with the multiwalled carbon nanotube through covalent bonding. As such, subtle structural arrangements associated with the glass transition temperature of the system are electronically amplified to produce the exceptionally large electronic responses reported in the paper, without the negatives associated with solid-liquid phase transitions. The subtle structural changes associated with glass transition processes are ordinarily too small to produce large enough electronic responses.

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

Poly(octadecyl acrylate)-Grafted Multiwalled Carbon Nanotube Composites for Wearable Temperature Sensors by Alexander J. Wang, Surendra Maharjan, Kang-Shyang Liao, Brian P. McElhenny, Kourtney D. Wright, Eoghan P. Dillon, Ram Neupane, Zhuan Zhu, Shuo Chen, Andrew R. Barron, Oomman K. Varghese, Jiming Bao, Seamus A. Curran. ACS Appl. Nano Mater. 2020, XXXX, XXX, XXX-XXX DOI: https://doi.org/10.1021/acsanm.9b02396 (Online) Publication Date:January 28, 2020 Copyright © 2020 American Chemical Society

This paper is behind a paywall.

COVID-19: caution and concern not panic

There’s a lot of information being pumped out about COVID-19 and not all of it is as helpful as it might be. In fact, the sheer volume can seem overwhelming despite one’s best efforts to be calm.

Here are a few things I’ve used to help relieve some fo the pressure as numbers in Canada keep rising.

Inspiration from the Italians

I was thrilled to find Emily Rumball’s March 18 ,2020 article titled, “Italians making the most of quarantine is just what the world needs right now (VIDEOS),” on the Daily Hive website. The couple dancing on the balcony while Ginger Rogers and Fred Astaire are shown dancing on the wall above is my favourite.

As the Italians practice social distancing and exercise caution, they are also demonstrating that “life goes on” even while struggling as one of the countries hit hardest by COVID-19.

Investigating viruses and the 1918/19 pandemic vs. COVID-19

There has been some mention of and comparison to the 1918/19 pandemic (also known as the Spanish flu) in articles by people who don’t seem to be particularly well informed about that earlier pandemic. Susan Baxter offers a concise and scathing explanation for why the 1918/19 situation deteriorated as much as it did in her February 8, 2010 posting. As for this latest pandemic (COVID-19), she explains what a virus actually is and suggests we all calm down in her March 17, 2020 posting. BTW, she has an interdisciplinary PhD for work largely focused on health economics. She is also a lecturer in the health sciences programme at Simon Fraser University (Vancouver, Canada). Full disclosure: She and I have a longstanding friendship.

Marilyn J. Roossinck, a professor of Plant Pathology and Environmental Microbiology at Pennsylvania State University, wrote a February 20, 2020 essay for The Conversation titled, “What are viruses anyway, and why do they make us so sick? 5 questions answered,”

4. SARS was a formidable foe, and then seemed to disappear. Why?

Measures to contain SARS started early, and they were very successful. The key is to stop the chain of transmission by isolating infected individuals. SARS had a short incubation period; people generally showed symptoms in two to seven days. There were no documented cases of anyone being a source of SARS without showing symptoms.

Stopping the chain of transmission is much more difficult when the incubation time is much longer, or when some people don’t get symptoms at all. This may be the case with the virus causing CoVID-19, so stopping it may take more time.

1918/19 pandemic vs. COVID-19

Angela Betsaida B. Laguipo, with a Bachelor of Nursing degree from the University of Baguio, Philippine is currently completing her Master’s Degree, has written a March 9, 2020 article for News Medical comparing the two pandemics,

The COVID-19 is fast spreading because traveling is an everyday necessity today, with flights from one country to another accessible to most.

Some places did manage to keep the virus at bay in 1918 with traditional and effective methods, such as closing schools, banning public gatherings, and locking down villages, which has been performed in Wuhan City, in Hubei province, China, where the coronavirus outbreak started. The same method is now being implemented in Northern Italy, where COVID-19 had killed more than 400 people.

The 1918 Spanish flu has a higher mortality rate of an estimated 10 to 20 percent, compared to 2 to 3 percent in COVID-19. The global mortality rate of the Spanish flu is unknown since many cases were not reported back then. About 500 million people or one-third of the world’s population contracted the disease, while the number of deaths was estimated to be up to 50 million.

During that time, public funds are mostly diverted to military efforts, and a public health system was still a budding priority in most countries. In most places, only the middle class or the wealthy could afford to visit a doctor. Hence, the virus has [sic] killed many people in poor urban areas where there are poor nutrition and sanitation. Many people during that time had underlying health conditions, and they can’t afford to receive health services.

I recommend reading Laguipo’s article in its entirety right down to the sources she cites at the end of her article.

Ed Yong’s March 20, 2020 article for The Atlantic, “Why the Coronavirus Has Been So Successful; We’ve known about SARS-CoV-2 for only three months, but scientists can make some educated guesses about where it came from and why it’s behaving in such an extreme way,” provides more information about what is currently know about the coronavirus, SATS-CoV-2,

One of the few mercies during this crisis is that, by their nature, individual coronaviruses are easily destroyed. Each virus particle consists of a small set of genes, enclosed by a sphere of fatty lipid molecules, and because lipid shells are easily torn apart by soap, 20 seconds of thorough hand-washing can take one down. Lipid shells are also vulnerable to the elements; a recent study shows that the new coronavirus, SARS-CoV-2, survives for no more than a day on cardboard, and about two to three days on steel and plastic. These viruses don’t endure in the world. They need bodies.

But why do some people with COVID-19 get incredibly sick, while others escape with mild or nonexistent symptoms? Age is a factor. Elderly people are at risk of more severe infections possibly because their immune system can’t mount an effective initial defense, while children are less affected because their immune system is less likely to progress to a cytokine storm. But other factors—a person’s genes, the vagaries of their immune system, the amount of virus they’re exposed to, the other microbes in their bodies—might play a role too. In general, “it’s a mystery why some people have mild disease, even within the same age group,” Iwasaki [Akiko Iwasaki of the Yale School of Medicine] says.

We still have a lot to learn about this.

Going nuts and finding balance with numbers

Generally speaking,. I find numbers help me to put this situation into perspective. It seems I’m not alone; Dr. Daniel Gillis’ (Guelph University in Ontario, Canada) March 18, 2020 blog post is titled, Statistics In A Time of Crisis.

Hearkening back in history, the Wikipedia entry for Spanish flu offers a low of 17M deaths in a 2018 estimate to a high of !00M deaths in a 2005 estimate. At this writing (Friday, March 20, 2020 at 3 pm PT), the number of coronovirus cases worldwide is 272,820 with 11, 313 deaths.

Articles like Michael Schulman’s March 16, 2020 article for the New Yorker might not be as helpful as one hope (Note: Links have been removed),

Last Wednesday night [March 11, 2020], not long after President Trump’s Oval Office address, I called my mother to check in about the, you know, unprecedented global health crisis [emphasis mine] that’s happening. She told me that she and my father were in a cab on the way home from a fun dinner at the Polo Bar, in midtown Manhattan, with another couple who were old friends.

“You went to a restaurant?!” I shrieked. This was several days after she had told me, through sniffles, that she was recovering from a cold but didn’t see any reason that she shouldn’t go to the school where she works. Also, she was still hoping to make a trip to Florida at the end of the month. My dad, a lawyer, was planning to go into the office on Thursday, but thought that he might work from home on Friday, if he could figure out how to link up his personal computer. …

… I’m thirty-eight, and my mother and father are sixty-eight and seventy-four, respectively. Neither is retired, and both are in good shape. But people sixty-five and older—more than half of the baby-boomer population—are more susceptible to COVID-19 and have a higher mortality rate, and my parents’ blithe behavior was as unsettling as the frantic warnings coming from hospitals in Italy.

Clearly, Schulman is concerned about his parents’ health and well being but the tone of near hysteria is a bit off-putting. We’re not in a crisis (exception: the Italians and, possibly, the Spanish and the French)—yet.

Tyler Dawson’s March 20, 2020 article in The Province newspaper (in Vancouver, British Columbia) offers dire consequences from COVID-19 before pivoting,

COVID-19 will leave no Canadian untouched.

Travel plans halted. First dates postponed. School semesters interrupted. Jobs lost. Retirement savings decimated. Some of us will know someone who has gotten sick, or tragically, died from the virus.

By now we know the terminology: social distancing, flatten the curve. Across the country, each province is taking measures to prepare, to plan for care, and the federal government has introduced financial measures amounting to more than three per cent of the country’s GDP to float the economy onward.

The response, says Steven Taylor, a University of British Columbia psychiatry professor and author of The Psychology of Pandemics, is a “balancing act.” [emphasis mine] Keep people alert, but neither panicked nor tuned out.

“You need to generate some degree of anxiety that gets people’s attention,” says Taylor. “If you overstate the message it could backfire.”

Prepare for uncertainty

In the same way experts still cannot come up with a definitive death rate for the 1918/19 pandemic, they are having trouble with this one too although, now, they’re trying to model the future rather than trying to establish what happened in the past. David Adam’s March 12, 2020 article forThe Scientist, provides some insight into the difficulties (Note: Links have been removed)

Like any other models, the projections of how the outbreak will unfold, how many people will become infected, and how many will die, are only as reliable as the scientific information they rest on. And most modelers’ efforts so far have focused on improving these data, rather than making premature predictions.

“Most of the work that modelers have done recently or in the first part of the epidemic hasn’t really been coming up with models and predictions, which is I think how most people think of it,” says John Edmunds, who works in the Centre for the Mathematical Modelling of Infectious Diseases at the London School of Hygiene & Tropical Medicine. “Most of the work has really been around characterizing the epidemiology, trying to estimate key parameters. I don’t really class that as modeling but it tends to be the modelers that do it.”

These variables include key numbers such as the disease incubation period, how quickly the virus spreads through the population, and, perhaps most contentiously, the case-fatality ratio. This sounds simple: it’s the proportion of infected people who die. But working it out is much trickier than it looks. “The non-specialists do this all the time and they always get it wrong,” Edmunds says. “If you just divide the total numbers of deaths by the total numbers of cases, you’re going to get the wrong answer.”

Earlier this month, Tedros Adhanom Ghebreyesus, the head of the World Health Organization, dismayed disease modelers when he said COVID-19 (the disease caused by the SARS-CoV-2 coronavirus) had killed 3.4 percent of reported cases, and that this was more severe than seasonal flu, which has a death rate of around 0.1 percent. Such a simple calculation does not account for the two to three weeks it usually takes someone who catches the virus to die, for example. And it assumes that reported cases are an accurate reflection of how many people are infected, when the true number will be much higher and the true mortality rate much lower.

Edmunds calls this kind of work “outbreak analytics” rather than true modeling, and he says the results of various specialist groups around the world are starting to converge on COVID-19’s true case-fatality ratio, which seems to be about 1 percent.[emphasis mine]

The 1% estimate in Adam’s article accords with Jeremy Samuel Faust’s (an emergency medicine physician at Brigham and Women’s Hospital in Boston, faculty in its division of health policy and public health, and an instructor at Harvard Medical School) estimates in a March 4, 2020 article (COVID-19 Isn’t As Deadly As We Think featured in my March 9, 2020 posting).

In a March 17, 2020 article by Steven Lewis (a health policy consultant formerly based in Saskatchewan, Canada; now living in Australia) for the Canadian Broadcasting Corporation’s (CBC) news online website, he covers some of the same ground and offers a somewhat higher projected death rate while refusing to commit,

Imagine you’re a chief public health officer and you’re asked the question on everyone’s mind: how deadly is the COVID-19 outbreak?

With the number of cases worldwide approaching 200,000, and 1,000 or more cases in 15 countries, you’d think there would be an answer. But the more data we see, the tougher it is to come up with a hard number.

Overall, the death rate is around four per cent — of reported cases. That’s also the death rate in China, which to date accounts for just under half the total number of global cases.

China is the only country where a) the outcome of almost all cases is known (85 per cent have recovered), and b) the spread has been stopped (numbers plateaued about a month ago). 

A four per cent death rate is pretty high — about 40 times more deadly than seasonal flu — but no experts believe that is the death rate. The latest estimate is that it is around 1.5 per cent. [emphasis mine] Other models suggest that it may be somewhat lower. 

The true rate can be known only if every case is known and confirmed by testing — including the asymptomatic or relatively benign cases, which comprise 80 per cent or more of the total — and all cases have run their course (people have either recovered or died). Aside from those in China, almost all cases identified are still active. 

Unless a jurisdiction systematically tests a large random sample of its population, we may never know the true rate of infection or the real death rate. 

Yet for all this unavoidable uncertainty, it is still odd that the rates vary so widely by country.

His description of the situation in Europe is quite interesting and worthwhile if you have the time to read it.

In the last article I’m including here, Murray Brewster offers some encouraging words in his March 20, 2020 piece about the preparations being made by the Canadian Armed Forces (CAF),

The Canadian military is preparing to respond to multiple waves of the COVID-19 pandemic which could stretch out over a year or more, the country’s top military commander said in his latest planning directive.

Gen. Jonathan Vance, chief of the defence staff, warned in a memo issued Thursday that requests for assistance can be expected “from all echelons of government and the private sector and they will likely come to the Department [of National Defence] through multiple points of entry.”

The directive notes the federal government has not yet directed the military to move into response mode, but if or when it does, a single government panel — likely a deputy-minister level inter-departmental task force — will “triage requests and co-ordinate federal responses.”

It also warns that members of the military will contract the novel coronavirus, “potentially threatening the integrity” of some units.

The notion that the virus caseload could recede and then return is a feature of federal government planning.

The Public Health Agency of Canada has put out a notice looking for people to staff its Centre for Emergency Preparedness and Response during the crisis and the secondment is expected to last between 12 and 24 months.

The Canadian military, unlike those in some other nations, has high-readiness units available. Vance said they are already set to reach out into communities to help when called.

Planners are also looking in more detail at possible missions — such as aiding remote communities in the Arctic where an outbreak could cripple critical infrastructure.

Defence analyst Dave Perry said this kind of military planning exercise is enormously challenging and complicated in normal times, let alone when most of the federal civil service has been sent home.

“The idea that they’re planning to be at this for year is absolutely bang on,” said Perry, a vice-president at the Canadian Global Affairs Institute.

In other words, concern and caution are called for not panic. I realize this post has a strongly Canada-centric focus but I’m hopeful others elsewhere will find this helpful.

Norwegian Institute for Water Research (NIVA) releases study on silver and titanium nanomaterials in wastewater

It turns out that silver and titanium nanomaterials (e.g. silver nanoparticles washed out of athletic clothing) in wastewater may have ‘negative’ and ‘positive’ effects on freshwater and marine life depending on the species.

A November 18, 2019 news item on Nanowerk provides an introduction to the research (Note: Links have been removed),

You may not always think about it when you do your laundry or flush the toilet; but whatever you eat, wear or apply on your skin ends up in wastewater and eventually reaches the environment. The use of nanoparticles in consumer products like textiles, foods and personal care products is increasing.

What is so special about nanoparticles, is their tiny size: One nanometer is one billionth of a meter. The small size gives nanoparticles unique and novel properties compared to their bigger counterparts and may for example reach locations that bigger particles cannot reach.
Further, pristine nanoparticles behave differently from nanoparticles in the environment. In the environment, nanoparticles are transformed by interacting and forming aggregates with other particles, elements or solids, and thereby obtain other physicochemical properties.

The transformation of these tiny particles in wastewater treatment processes and their effect on freshwater and marine organisms, have largely been unknown.
Increased mortality of marine crustaceans.

In a study (“Ecotoxicological Effects of Transformed Silver and Titanium Dioxide Nanoparticles in the Effluent from a Lab-Scale Wastewater Treatment System”) conducted at the Norwegian Institute for Water Research (NIVA), Anastasia Georgantzopoulou and colleagues from NIVA and SINTEF investigated how silver and titanium dioxide nanoparticles behave in wastewater treatment plants, and how marine and freshwater organisms are affected by them.

Exposure to treated wastewater did not have any adverse effects on the freshwater crustacean Daphnia magna. (Photo: NIVA)

A November 18, 2019 NIVA press release, which originated the news item, fills in the details,

The researchers made a laboratory-scale wastewater treatment plant, using sludge from a wastewater treatment plant in Norway. They added environmentally relevant concentrations of silver (Ag) and titanium dioxide (TiO2) nanoparticles over a 5-week period and used the treated wastewater to assess the effects of transformed nanoparticles on freshwater and marine organisms, as well as on gill cells from rainbow trout.

The experiment demonstrated contrasting effects on the two crustacean species. For the marine copepod (Tisbe battagliai), mortality increased by 20-45%, whereas exposure to ttreated wastewater did not have any adverse effects on the freshwater crustacean (Daphnia magna).

“These differences are probably due, at least partly, to the two species’ different feeding habits, in combination with the fact that the nanoparticles showed a strong association to solids present in the wastewater”, Georgantzopoulou says, and explains:

“Daphnia magna is an organism that filters water for food, whereas the marine copepod feeds on bottom surfaces – like effluent solids that have settled out from the water. The bottom feeding crustacean is therefore more likely to ingest nanoparticles, and thereby be affected by solid-associated nanoparticles”. 

Effects on algal species

Nanoparticle-containing treated wastewater also affected algal growth, but the two algae species did not have a common response: The marine algae (Skeletonema pseudocostatum) responded with a 20-40 % growth inhibition, while the algal growth of the freshwater algae (Raphidocelis subcapitata) was actually stimulated, by a 40 % increase, accompanied by increased cell aggregation. The latter is probably some kind of a defense mechanism, aiming to decrease the surface area exposed to toxic particles.

“The results from our study indicate that algal responses to the treated wastewater exposure are species-dependent. This is possibly due to differences in algal cell size, surface area, and cell wall composition”, the NIVA researcher explains.

Increased permeability of fish gill cells

The researchers also found effects of silver and titanium nanoparticles on fish gill cells using an in vitro gill cell line model. As large amounts of water are passing through the gills, and they constitute a barrier to the external environment, this organ is highly exposed to water-borne contaminants, including nanoparticles.

“Exposure to nanoparticle-containing wastewater lead to an increase in reactive oxygen species, a group of molecules that can easily react with and damage cells. This was followed by increased permeability of the gill cells, leading to a compromised barrier function”, Georgantzopoulou says.

“However, the concentrations of silver and titanium nanoparticles in the treated wastewater were too low to fully account for the effects on cell permeability alone. The wastewater effluent is a complex mixture of materials, and the permeability response is probably caused by a combination of the presence of nanoparticles and other stressors”, Georgantzopoulou adds.

Wastewater treatment-transformation of nanoparticles

“We carried out this study on wastewater treatment plant-transformed nanoparticles, and compared them to pristine nanoparticles, as the former is more relevant to what is actually happening in the environment. The increased toxicity of the transformed nanomaterials observed in the study indicates that the effects cannot be predicted by assessing the effects of nanomaterials in their pristine form and highlights the importance of understanding their behavior, environmental transformation and interaction with organisms. Future studies should take nanoparticle transformation into account and focus on a more relevant experimental exposure conditions incorporating transformed nanoparticles in more long-term impact studies to provide a better understanding of their potential impacts”, Georgantzopoulou concludes.

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

Ecotoxicological Effects of Transformed Silver and Titanium Dioxide Nanoparticles in the Effluent from a Lab-Scale Wastewater Treatment System by Anastasia Georgantzopoulou, Patricia Almeida Carvalho, Christian Vogelsang, Mengstab Tilahun, Kuria Ndungu, Andy M. Booth, Kevin V. Thomas, Ailbhe Macken. Environ. Sci. Technol. 2018, 52, 16, 9431-9441 DOI: https://doi.org/10.1021/acs.est.8b01663 Publication Date:July 26, 2018 Copyright © 2018 American Chemical Society

This paper is behind a paywall.

Replacing human tissue with nanostructured rubber-like material?

The scientists started out with an idea for creating a bone-like material)and ended up with something completely different. A March 16, 2020 news item on ScienceDaily announces news about a new material that could be used to replace human tissue,

Researchers from Chalmers University of Technology, Sweden, have created a new, rubber-like material with a unique set of properties, which could act as a replacement for human tissue in medical procedures. The material has the potential to make a big difference to many people’s lives. The research was recently published in the highly regarded scientific journal ACS Nano.

In the development of medical technology products, there is a great demand for new naturalistic materials suitable for integration with the body. Introducing materials into the body comes with many risks, such as serious infections, among other things. Many of the substances used today, such as Botox, are very toxic. There is a need for new, more adaptable materials.

In the new study, the Chalmers researchers developed a material consisting solely of components that have already been shown to work well in the body.

A March 17, 2020 Chalmers University of Technology press release (also on EurekAlert but published on March 16, 2020), which originated the news item, describes the scientists’ surprising discovery and how they shifted their focus,

The foundation of the material is the same as plexiglass, a material which is common in medical technology applications. Through redesigning its makeup, and through a process called nanostructuring, they gave the newly patented material a unique combination of properties. The researchers’ initial intention was to produce a hard bone-like material, but they were met with surprising results.

“We were really surprised that the material turned to be very soft, flexible and extremely elastic. It would not work as a bone replacement material, we concluded. But the new and unexpected properties made our discovery just as exciting,” says Anand Kumar Rajasekharan, PhD in Materials Science and one of the researchers behind the study.

The results showed that the new rubber-like material may be appropriate for many applications which require an uncommon combination of properties – high elasticity, easy processability, and suitability for medical uses.

“The first application we are looking at now is urinary catheters. The material can be constructed in such a way that prevents bacteria from growing on the surface, meaning it is very well suited for medical uses,” says Martin Andersson, research leader for the study and Professor of Chemistry at Chalmers.

The structure of the new nano-rubber material allows its surface to be treated so that it becomes antibacterial, in a natural, non-toxic way. This is achieved by sticking antimicrobial peptides – small proteins which are part of our innate immune system – onto its surface. This can help reduce the need for antibiotics, an important contribution to the fight against growing antibiotic resistance.

Because the new material can be injected and inserted via keyhole surgery, it can also help reduce the need for drastic surgery and operations to rebuild parts of the body. The material can be injected via a standard cannula as a viscous fluid, so that it forms its own elastic structures within the body. Or, the material can also be 3D printed into specific structures as required.

“There are many diseases where the cartilage breaks down and friction results between bones, causing great pain for the affected person. This material could potentially act as a replacement in those cases,” Martin Andersson continues.

A further advantage of the material is that it contains three-dimensionally ordered nanopores. This means it can be loaded with medicine, for various therapeutic purposes such as improving healing and reducing inflammation. This allows for localised treatment, avoiding, for example, having to treat the entire body with drugs, something that could help reduce problems associated with side effects. Since it is non-toxic, it also works well as a filler – the researchers see plastic surgery therefore as another very interesting potential area of application for the new material.

“I am now working full time with our newly founded company, Amferia, to get the research out to industry. I have been pleased to see a lot of real interest in our material. It’s promising in terms of achieving our goal, which is to provide real societal benefit,” Anand concludes.

The path of the research to societal benefit and commercialisation, through start-up company Amferia and Chalmers Ventures

In order for the discovery of the new material to be useful and commercialised, the researchers patented their innovation before the study was published. The patent is owned by start-up company Amferia, which was founded by Martin Andersson and Anand Kumar Rajasekharan, two of the researchers behind the study, as well as researcher Saba Atefyekta who recently completed a PhD in Materials Science at Chalmers. Anand is now CEO of Amferia and will drive the application of the new material and development of the company.

Amferia has previously been noted for an antibacterial wound patch developed by the same team. Amferia now has the innovation of both the new nano-rubber and the antibacterial wound patch. The development of the company and the innovations’ path to making profit are now being carried out in collaboration with Chalmers Ventures, a subsidiary of Chalmers University of Technology.

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

Tough Ordered Mesoporous Elastomeric Biomaterials Formed at Ambient Conditions by Anand K. Rajasekharan, Christoffer Gyllensten, Edvin Blomstrand, Marianne Liebi, Martin Andersson. ACS Nano 2020, 14, 1, 241-254 DOI: https://doi.org/10.1021/acsnano.9b01924 Publication Date:December 17, 2019 Copyright © 2019 American Chemical Society

This paper is behind a paywall.

Flexible graphene-rubber sensor for wearables

Courtesy: University of Waterloo

This waffled, greyish thing may not look like much but scientists are hopeful that it can be useful as a health sensor in athletic shoes and elsewhere. A March 6, 2020 news item on Nanowerk describes the work in more detail (Note: Links have been removed),

Researchers have utilized 3D printing and nanotechnology to create a durable, flexible sensor for wearable devices to monitor everything from vital signs to athletic performance (ACS Nano, “3D-Printed Ultra-Robust Surface-Doped Porous Silicone Sensors for Wearable Biomonitoring”).

The new technology, developed by engineers at the University of Waterloo [Ontario, Canada], combines silicone rubber with ultra-thin layers of graphene in a material ideal for making wristbands or insoles in running shoes.

A March 6, 2020 University of Waterloo news release, which originated the news item, delves further,

When that rubber material bends or moves, electrical signals are created by the highly conductive, nanoscale graphene embedded within its engineered honeycomb structure.

“Silicone gives us the flexibility and durability required for biomonitoring applications, and the added, embedded graphene makes it an effective sensor,” said Ehsan Toyserkani, research director at the Multi-Scale Additive Manufacturing (MSAM) Lab at Waterloo. “It’s all together in a single part.”

Fabricating a silicone rubber structure with such complex internal features is only possible using state-of-the-art 3D printing – also known as additive manufacturing – equipment and processes.

The rubber-graphene material is extremely flexible and durable in addition to highly conductive.

“It can be used in the harshest environments, in extreme temperatures and humidity,” said Elham Davoodi, an engineering PhD student at Waterloo who led the project. “It could even withstand being washed with your laundry.”

The material and the 3D printing process enable custom-made devices to precisely fit the body shapes of users, while also improving comfort compared to existing wearable devices and reducing manufacturing costs due to simplicity.

Toyserkani, a professor of mechanical and mechatronics engineering, said the rubber-graphene sensor can be paired with electronic components to make wearable devices that record heart and breathing rates, register the forces exerted when athletes run, allow doctors to remotely monitor patients and numerous other potential applications.

Researchers from the University of California, Los Angeles and the University of British Columbia collaborated on the project.

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

3D-Printed Ultra-Robust Surface-Doped Porous Silicone Sensors for Wearable Biomonitoring by Elham Davoodi, Hossein Montazerian, Reihaneh Haghniaz, Armin Rashidi, Samad Ahadian, Amir Sheikhi, Jun Chen, Ali Khademhosseini, Abbas S. Milani, Mina Hoorfar, Ehsan Toyserkani. ACS Nano 2020, 14, 2, 1520-1532 DOI: https://doi.org/10.1021/acsnano.9b06283 Publication Date: January 6, 2020 Copyright © 2020 American Chemical Society

This paper is behind a paywall.