Tag Archives: University of Tokyo

Plant fibers (nanocellulose) for more sustainable devices

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Thank you to Junichiro Shiomi and the University of Tokyo for this image,

Caption: An artist’s interpretation of the way natural cellulose fibers are combined to form the CNF [cellulose nanofiber] yarn, and a magnified section showing the nanoscopic rod-shaped filaments within the yarn bundle. Credit: ©2022 Junichiro Shiomi

The research into cellulose nanofibers (CNFs) announced in this November 4, 2022 news item on ScienceDaily comes from the University of Tokyo,

Plant-derived materials such as cellulose often exhibit thermally insulating properties. A new material made from nanoscale cellulose fibers shows the reverse, high thermal conductivity. This makes it useful in areas previously dominated by synthetic polymer materials. Materials based on cellulose have environmental benefits over polymers, so research on this could lead to greener technological applications where thermal conductivity is needed.

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Both cellulose nanofibers/nanofibres and cellulose nanofibrils are abbreviated to CNFs. This seems a bit confusing so I went looking for an explanation and found this September 22, 2020 posting (scroll down about 35% of the way) by professor Hatsuo Ishida, Department of Macromolecular Science and Engineering at Case Western Reserve University,

Both fiber and fibril indicate long thread-like materials and their meanings are essentially the same. However, the word,”fibril,” emphasizes a thin fiber. Therefore, the use of the word, “nano fibril,” is rather redundant. The word,”fibril” is often used for distinguishing high temperature water vapor treated cellulose fibers that are spread into very thin fibers from the whiskers prepared by the acid treatment of cellulosic materials. The word,” microfibril” is more often used than “nano fibril.” Some also use the word,”cellulose nanocrystal.” Cellulose whiskers are single crystals of materials and a typical length is less than a micrometer (one of the longest cellulose whiskers can be prepared from a sea creature called tunicate), whereas the cellulose nano fibril has much longer length. This material is much easier to scale up whereas cellulose whiskers are not as easily scale up as the nano fibrils. The word fiber has no implication and it is simply a thread like object. Thus, even if the diameter is more than hundred micrometers, as long as the length is much longer (high aspect ratio), you may call it a fiber, whereas such a thick fiber is seldom called a fibril.

Thank you professor Ishida!

A November 4, 2022 University of Tokyo press release (also on EurekAlert), which originated the news item, explains the interest in nanocellulose and its thermal properties,

Cellulose is a key structural component of plant cell walls and is the reason why trees can grow to such heights. But the secret of its material strength actually lies in its overlapping nanoscopic fibers. In recent years, many commercial products have used cellulose nanofiber (CNF) materials because their strength and durability make them a good replacement for polymer-based materials such as plastics that can be detrimental to the environment. But now and for the first time, a research team led by Professor Junichiro Shiomi from the University of Tokyo’s Graduate School of Engineering has investigated previously unknown thermal properties of CNF, and their findings show these materials could be even more useful still.

“If you see plant-derived materials such as cellulose or woody biomass used in applications, it’s typically mechanical or thermally insulating properties that are being employed,” said Shiomi. “When we explored the thermal properties of a yarn made from CNF, however, we found that they show a different kind of thermal behavior, thermal conduction, and it’s very significant, around 100 times higher than that of typical woody biomass or cellulose paper.”

The reason yarn made from CNF can conduct heat so well is due to the way it’s made. Cellulose fibers in nature are very disorganized, but a process called the flow-focusing method combines cellulose fibers, orientating them in the same way, to create CNF. It’s this tightly bound and aligned bundle of rod-shaped fibers that allows heat to transfer along the bundle, whereas in a more chaotic structure it would dissipate heat more readily.

“Our main challenge was how to measure the thermal conductivity of such small physical samples and with great accuracy,” said Shiomi. “For this, we turned to a technique called T-type thermal conductivity measurement. It allowed us to measure the thermal conductivity of the rod-shaped CNF yarn samples which are only micrometers (a micrometer equaling one-thousandth of a millimeter) in diameter. But the next step for us is to perform accurate thermal tests on two-dimensional textilelike samples.”

Shiomi and his team hope that their investigation and future explorations into the use of CNF as a thermally conductive material could give engineers an alternative to some environmentally damaging polymers. In applications where heat transfer is important, such as certain electronic or computational components, it could greatly reduce the consequences of discarded electronic equipment, or e-waste, thanks to the biodegradable nature of CNF and other plant-based materials.

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

Enhanced High Thermal Conductivity Cellulose Filaments via Hydrodynamic Focusing by Guantong Wang, Masaki Kudo, Kazuho Daicho, Sivasankaran Harish, Bin Xu, Cheng Shao, Yaerim Lee, Yuxuan Liao, Naoto Matsushima, Takashi Kodama, Fredrik Lundell, L. Daniel Söderberg, Tsuguyuki Saito, and Junichiro Shiomi. Nano Lett. 2022, 22, 21, 8406–8412 DOI: https://doi.org/10.1021/acs.nanolett.2c02057 Publication Date:October 25, 2022 Copyright © 2022 The Authors. Published by American Chemical Society

This paper is open access.

Robots with living human skin tissue?

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So far, it looks like they’ve managed a single robotic finger. I expect it will take a great deal more work before an entire robotic hand is covered in living skin. BTW, I have a few comments at the end of this post.

Caption: Illustration showing the cutting and healing process of the robotic finger (A), its anchoring structure (B) and fabrication process (C). Credit: ©2022 Takeuchi et al.

I have two news releases highlighting the work. This a June 9, 2022 Cell Press news release,

From action heroes to villainous assassins, biohybrid robots made of both living and artificial materials have been at the center of many sci-fi fantasies, inspiring today’s robotic innovations. It’s still a long way until human-like robots walk among us in our daily lives, but scientists from Japan are bringing us one step closer by crafting living human skin on robots. The method developed, presented June 9 in the journal Matter, not only gave a robotic finger skin-like texture, but also water-repellent and self-healing functions.

“The finger looks slightly ‘sweaty’ straight out of the culture medium,” says first author Shoji Takeuchi, a professor at the University of Tokyo, Japan. “Since the finger is driven by an electric motor, it is also interesting to hear the clicking sounds of the motor in harmony with a finger that looks just like a real one.”

Looking “real” like a human is one of the top priorities for humanoid robots that are often tasked to interact with humans in healthcare and service industries. A human-like appearance can improve communication efficiency and evoke likability. While current silicone skin made for robots can mimic human appearance, it falls short when it comes to delicate textures like wrinkles and lacks skin-specific functions. Attempts at fabricating living skin sheets to cover robots have also had limited success, since it’s challenging to conform them to dynamic objects with uneven surfaces.

“With that method, you have to have the hands of a skilled artisan who can cut and tailor the skin sheets,” says Takeuchi. “To efficiently cover surfaces with skin cells, we established a tissue molding method to directly mold skin tissue around the robot, which resulted in a seamless skin coverage on a robotic finger.”

To craft the skin, the team first submerged the robotic finger in a cylinder filled with a solution of collagen and human dermal fibroblasts, the two main components that make up the skin’s connective tissues. Takeuchi says the study’s success lies within the natural shrinking tendency of this collagen and fibroblast mixture, which shrank and tightly conformed to the finger. Like paint primers, this layer provided a uniform foundation for the next coat of cells—human epidermal keratinocytes—to stick to. These cells make up 90% of the outermost layer of skin, giving the robot a skin-like texture and moisture-retaining barrier properties.

The crafted skin had enough strength and elasticity to bear the dynamic movements as the robotic finger curled and stretched. The outermost layer was thick enough to be lifted with tweezers and repelled water, which provides various advantages in performing specific tasks like handling electrostatically charged tiny polystyrene foam, a material often used in packaging. When wounded, the crafted skin could even self-heal like humans’ with the help of a collagen bandage, which gradually morphed into the skin and withstood repeated joint movements.

“We are surprised by how well the skin tissue conforms to the robot’s surface,” says Takeuchi. “But this work is just the first step toward creating robots covered with living skin.” The developed skin is much weaker than natural skin and can’t survive long without constant nutrient supply and waste removal. Next, Takeuchi and his team plan to address those issues and incorporate more sophisticated functional structures within the skin, such as sensory neurons, hair follicles, nails, and sweat glands.

“I think living skin is the ultimate solution to give robots the look and touch of living creatures since it is exactly the same material that covers animal bodies,” says Takeuchi.

A June 10, 2022 University of Tokyo news release (also on EurekAlert but published June 9, 2022) covers some of the same ground while providing more technical details,

Researchers from the University of Tokyo pool knowledge of robotics and tissue culturing to create a controllable robotic finger covered with living skin tissue. The robotic digit had living cells and supporting organic material grown on top of it for ideal shaping and strength. As the skin is soft and can even heal itself, so could be useful in applications that require a gentle touch but also robustness. The team aims to add other kinds of cells into future iterations, giving devices the ability to sense as we do.

Professor Shoji Takeuchi is a pioneer in the field of biohybrid robots, the intersection of robotics and bioengineering. Together with researchers from around the University of Tokyo, he explores things such as artificial muscles, synthetic odor receptors, lab-grown meat, and more. His most recent creation is both inspired by and aims to aid medical research on skin damage such as deep wounds and burns, as well as help advance manufacturing.

“We have created a working robotic finger that articulates just as ours does, and is covered by a kind of artificial skin that can heal itself,” said Takeuchi. “Our skin model is a complex three-dimensional matrix that is grown in situ on the finger itself. It is not grown separately then cut to size and adhered to the device; our method provides a more complete covering and is more strongly anchored too.”

Three-dimensional skin models have been used for some time for cosmetic and drug research and testing, but this is the first time such materials have been used on a working robot. In this case, the synthetic skin is made from a lightweight collagen matrix known as a hydrogel, within which several kinds of living skin cells called fibroblasts and keratinocytes are grown. The skin is grown directly on the robotic component which proved to be one of the more challenging aspects of this research, requiring specially engineered structures that can anchor the collagen matrix to them, but it was worth it for the aforementioned benefits.

“Our creation is not only soft like real skin but can repair itself if cut or damaged in some way. So we imagine it could be useful in industries where in situ repairability is important as are humanlike qualities, such as dexterity and a light touch,” said Takeuchi. “In the future, we will develop more advanced versions by reproducing some of the organs found in skin, such as sensory cells, hair follicles and sweat glands. Also, we would like to try to coat larger structures.”

The main long-term aim for this research is to open up new possibilities in advanced manufacturing industries. Having humanlike manipulators could allow for the automation of things currently only achievable by highly skilled professionals. Other areas such as cosmetics, pharmaceuticals and regenerative medicine could also benefit. This could potentially reduce cost, time and complexity of research in these areas and could even reduce the need for animal testing.

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

Living skin on a robot by Michio Kawai, Minghao Nie, Haruka Oda, Yuya Morimoto, Shoji Takeuchi. Matter DOI: https://doi.org/10.1016/j.matt.2022.05.019 Published:June 09, 2022

This paper appears to be open access.

There more images and there’s at least one video all of which can be found by clicking on the links to one or both of the news releases and to the paper. Personally, I found the images fascinating and …

Frankenstein, cyborgs, and more

The word is creepy. I find the robot finger images fascinating and creepy. The work brings to mind Frankenstein (by Mary Shelley) and The Island of Dr. Moreau (by H. G. Wells) both of which feature cautionary tales. Dr. Frankenstein tries to bring a dead ‘person’ assembled with parts from various corpses to life and Dr. Moreau attempts to create hybrids composed humans and animals. It’s fascinating how 19th century nightmares prefigure some of the research being performed now.

The work also brings to mind the ‘uncanny valley’, a term coined by Masahiro Mori, where people experience discomfort when something that’s not human seems too human. I have an excerpt from an essay that Mori wrote about the uncanny valley in my March 10, 2011 posting; scroll down about 50% of the way.) The diagram which accompanies it illustrates the gap between the least uncanny or the familiar (a healthy person, a puppet, etc.) and the most uncanny or the unfamiliar (a corpse, a zombie, a prosthetic hand).

Mori notes that the uncanny valley is not immovable; things change and the unfamiliar becomes familiar. Presumably, one day, I will no longer find robots with living skin to be creepy.

All of this changes the meaning (for me) of a term i coined for this site, ‘machine/flesh’. At the time, I was thinking of prosthetics and implants and how deeply they are being integrated into the body. But this research reverses the process. Now, the body (skin in this case) is being added to the machine (robot).

Replace plastic with Choetsu which waterproofs paper and degrades safely

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It’s good to see research into practical ways of replacing plastic. From a May 13, 2022 news item on ScienceDaily,

For our sake and the environment, there is a considerable amount of research into the reduction of plastic for many and various applications. For the first time, researchers have found a way to imbue relatively sustainable paper materials with some of the useful properties of plastic. This can be done easily, cost effectively, and efficiently. A coating called Choetsu not only waterproofs paper, but also maintains its flexibility and degrades safely as well.

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Caption: A classic origami crane made from paper and coated with Choetsu (left) and uncoated (right). When submerged in water, the coated paper crane keeps its shape while the uncoated one quickly saturates with water and starts to disintegrate. Credit: ©2022 Hiroi et al.

A May 13, 2022 University of Tokyo press release (also on EurekAlert), which originated the news item, describes the work in more detail,

It’s hard to escape the fact that plastic materials are by and large detrimental to the environment. You’ve probably seen images of plastic pollution washing up on beaches, spoiling rivers and killing countless animals. Yet the problem often seems completely out of our hands given the ubiquity of plastic materials in everyday life. Professor Zenji Hiroi from the Institute for Solid State Physics at the University of Tokyo and his team explore ways materials science can help, and their recent discovery aims to replace some uses of plastic with something more sustainable: Paper.

“The main problem with plastic materials as I see it is their inability to degrade quickly and safely,” said Hiroi. “There are materials that can degrade safely, such as paper, but obviously paper cannot fulfill the vast range of uses plastic can. However, we’ve found a way to give paper some of the nice properties of plastic, but with none of the detriments. We call it Choetsu, a low-cost biodegradable coating that adds waterproofing and strength to simple paper.”

Choetsu is a combination of materials which, when applied to paper, spontaneously generate a strong and waterproof film when it makes contact with moisture in the air. The coating consists of safe and low-cost chemicals, mostly methyltrimethoxysilane, some isopropyl alcohol, and a small amount of tetraisopropyl titanate. Paper structures, for example food containers, are sprayed with or dipped into this liquid mixture and are dried at room temperature. Once dry, a thin layer of silica containing methyl, a type of alcohol, forms on the cellulose making up the paper, providing the strong and waterproof properties.

Furthermore, reactions that take place during the coating procedure automatically creates a layer of titanium dioxide nanoparticles. These give rise to a dirt- and bacterial-repellent property known as photocatalytic activity, which protects the coated item for an extended period of time. All of the chemicals involved in the coating break down over time into harmless things such as carbon, water and sandlike silicon.

“The technical challenge is complete, and some applications could be realized soon, such as items for consuming, packaging or storing food,” said Hiroi. “We now hope to use this approach on other kinds of materials as well. The liquid composition can be tuned for other materials, and we can create a dirt- and mold-resistant coating that could form onto glass, ceramics and even other plastics to extend their usefulness. Alongside researcher Yoko Iwamiya, who has been working in this field for some time now, and the rest of my team, I hope we can do something truly beneficial for the world.”

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

Photocatalytic Silica–Resin Coating for Environmental Protection of Paper as a Plastic Substitute by Yoko Iwamiya, Daisuke Nishio-Hamane, Kazuhiro Akutsu-Suyama, Hiroshi Arima-Osonoi, Mitsuhiro Shibayama, and Zenji Hiroi. Ind. Eng. Chem. Res. 2022, XXXX, XXX, XXX-XXX DOI: https://doi.org/10.1021/acs.iecr.2c00784 Publication Date: May 13, 2022 © 2022 American Chemical Society

This paper is behind a paywall.

Fluorine-based nanostructures for desalination

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A May 16, 2022 article by Qamariya Nasrullah for cosmosmagazine.com describes research from Japan on desalination (Note: A link has been removed),

Water supply is a growing global issue, especially with climate change bringing on more droughts. Seawater desalination is used worldwide to filter up to 97.4 million cubic metres per day. Two methods – thermal and reverse osmosis – predominate; both have huge energy costs.

In a pioneering study published in Science, researchers have used a fluorine-based nanostructure to successfully filter salt from water faster and more efficiently than other current technologies. But how does it work?

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A May 12, 2022 University of Tokyo press release (also on EurekAlert), which originated the news item, provides the answer to Nasrullah’s question,

If you’ve ever cooked with a nonstick Teflon-coated frying pan, then you’ve probably seen the way that wet ingredients slide around it easily. This happens because the key component of Teflon is fluorine, a lightweight element that is naturally water repelling, or hydrophobic. Teflon can also be used to line pipes to improve the flow of water. Such behavior caught the attention of Associate Professor Yoshimitsu Itoh from the Department of Chemistry and Biotechnology at the University of Tokyo and his team. It inspired them to explore how pipes or channels made from fluorine might operate on a very different scale, the nanoscale.

“We were curious to see how effective a fluorous nanochannel might be at selectively filtering different compounds, in particular, water and salt. And, after running some complex computer simulations, we decided it was worth the time and effort to create a working sample,” said Itoh. “There are two main ways to desalinate water currently: thermally, using heat to evaporate seawater so it condenses as pure water, or by reverse osmosis, which uses pressure to force water through a membrane that blocks salt. Both methods require a lot of energy, but our tests suggest fluorous nanochannels require little energy, and have other benefits too.”

The team created test filtration membranes by chemically synthesizing nanoscopic fluorine rings, which were stacked and embedded in an otherwise impermeable lipid layer, similar to the organic molecules that make up cell walls. They created several test samples with nanorings between about 1 and 2 nanometers. For reference, a human hair is almost 100,000 nanometers wide. To test the effectiveness of their membranes, Itoh and the team measured the presence of chlorine ions, one of the major components of salt — the other being sodium — on either side of the test membrane.

“It was very exciting to see the results firsthand. The smaller of our test channels perfectly rejected incoming salt molecules, and the larger channels too were still an improvement over other desalination techniques and even cutting-edge carbon nanotube filters,” said Itoh. “The real surprise to me was how fast the process occurred. Our sample worked around several thousand times faster than typical industrial devices, and around 2,400 times faster than experimental carbon nanotube-based desalination devices.”

As fluorine is electrically negative, it repels negative ions such as the chlorine found in salt. But an added bonus of this negativity is that it also breaks down what are known as water clusters, essentially loosely bound groups of water molecules, so that they pass through the channels quicker. The team’s fluorine-based water desalination membranes are more effective, faster, require less energy to operate and are made to be very simple to use as well, so what’s the catch?

“At present, the way we synthesize our materials is relatively energy-intensive itself; however, this is something we hope to improve upon in upcoming research. And, given the longevity of the membranes and their low operational costs, the overall energy costs will be much lower than with current methods,” said Itoh. “Other steps we wish to take are of course scaling this up. Our test samples were single nanochannels, but with the help of other specialists, we hope to create a membrane around 1 meter across in several years. In parallel with these manufacturing concerns, we’re also exploring whether similar membranes could be used to reduce carbon dioxide or other undesirable waste products released by industry.”

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

Ultrafast water permeation through nanochannels with a densely fluorous interior surface by Yoshimitsu Itoh, Shuo Chen, Jyota Hirahara, Takeshi Konda, Tsubasa Aoki, Takumi Ueda, Ichio Shimada, James J. Cannon, Cheng Shao, Junichiro Shiomi, Kazuhito V. Tabata, Hiroyuki Noji, Kohei Sato, and Takuzo Aida. Science • 12 May 2022 • Vol 376, Issue 6594 • pp. 738-743 • DOI: 10.1126/science.abd0966

This paper is behind a paywall.

Philosophy and science in Tokyo, Japan from Dec. 1-2, 2022

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I have not seen a more timely and à propos overview for a meeting/conference/congress that this one for Tokyo Forum 2022 (hosted by the University of Tokyo and South Korea’s Chey Institute for Advanced Studies),

“Dialogue between Philosophy and Science: In a World Facing War, Pandemic, and Climate Change”

In the face of war, a pandemic, and climate change, we cannot repeat the history of the last century, in which our ancestors headed down the road to division, global conflict, and environmental destruction.

How can we live more fully and how do we find a new common understanding about what our society should be? Tokyo Forum 2022 will tackle these questions through a series of in-depth dialogues between philosophy and science. The dialogues will weave together the latest findings and deep contemplation, and explore paths that could lead us to viable answers and solutions.

Philosophy of the 21st century must contribute to the construction of a new universality based on locality and diversity. It should be a universality that is open to co-existing with other non-human elements, such as ecosystems and nature, while severely criticizing the understanding of history that unreflectively identifies anthropocentrism with universality.

Science in the 21st century also needs to dispense with its overarching aura of supremacy and lack of self-criticism. There is a need for scientists to make efforts to demarcate their own limits. This also means reexamining what ethics means for science.

Tokyo Forum 2022 will offer multifaceted dialogues between philosophers, scientists, and scholars from various fields of study on the state and humanity in the 21st century, with a view to imagining and proposing a vision of the society we need.

Here are some details about the hybrid event from a November 4, 2022 University of Tokyo press release on EurekAlert,

The University of Tokyo and South Korea’s Chey Institute for Advanced Studies will host Tokyo Forum 2022 from Dec. 1-2, 2022. Under this year’s theme “Dialogue between Philosophy and Science,” the annual symposium will bring together philosophers, scientists and scholars in various fields from around the world for multifaceted dialogues on humanity and the state in the 21st century, while envisioning the society we need.

The event is free and open to the public, and will be held both on site at Yasuda Auditorium of the University of Tokyo and online via livestream. [emphases mine]

Keynote speakers lined up for the first day of the two-day symposium are former U.N. Secretary-General Ban Ki-moon, University of Chicago President Paul Alivisatos and Mariko Hasegawa, president of the Graduate University for Advanced Studies in Japan.

Other featured speakers on the event’s opening day include renowned modern thinker and author Professor Markus Gabriel of the University of Bonn, and physicist Hirosi Ooguri, director of the Kavli Institute for the Physics and Mathematics of the Universe at the University of Tokyo and professor at the California Institute of Technology, who are scheduled to participate in the high-level discussion on the dialogue between philosophy and science.

Columbia University Professor Jeffrey Sachs will take part in a panel discussion, also on Day 1, on tackling global environmental issues with stewardship of the global commons — the stable and resilient Earth system that sustains our lives — as a global common value.

The four panel discussions slated for Day 2 will cover the role of world philosophy in addressing the problems of a globalized world; transformative change for a sustainable future by understanding the diverse values of nature and its contributions to people; the current and future impacts of autonomous robots on society; and finding collective solutions and universal values to pursue equitable and sustainable futures for humanity by looking at interconnections among various fields of inquiry.

Opening remarks will be delivered by University of Tokyo President Teruo Fujii and South Korea’s SK Group Chairman Chey Tae-won, on Day 1. Fujii and Chey Institute President Park In-kook will make closing remarks following the wrap-up session on the second and final day.

Tokyo Forum with its overarching theme “Shaping the Future” is held annually since 2019 to stimulate discussions on finding the best ideas for shaping the world and humanity in the face of complex situations where the conventional wisdom can no longer provide answers.

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For more information about the program and speakers of Tokyo Forum 2022, visit the event website and social media accounts:

Website: https://www.tokyoforum.tc.u-tokyo.ac.jp/en/index.html

Twitter: https://twitter.com/UTokyo_forum

Facebook: https://www.facebook.com/UTokyo.tokyo.forum/

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To register, fill out the registration form on the Tokyo Forum 2022 website (registration is free but required [emphasis mine] to attend the event): https://www.tokyo-forum-form.com/apply/audiences/en

I’m not sure how they are handling languages. I’m guessing that people are speaking in the language they choose and translations (subtitles or dubbing) are available. For anyone who may have difficulty attending due to timezone issues, there are archives for previous Tokyo Forums. Presumably 2022 will be added at some point in the future.

Growing electronics on trees

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An April 26, 2022 news item on phys.org caught my eye with its mention of nanocellulose, trees, and electronics,

Electronics can grow on trees thanks to nanocellulose paper semiconductors

Semiconducting nanomaterials with 3D network structures have high surface areas and a lot of pores that make them excellent for applications involving adsorbing, separating, and sensing. However, simultaneously controlling the electrical properties and creating useful micro- and macro-scale structures, while achieving excellent functionality and end-use versatility, remains challenging. Now, Osaka University researchers, in collaboration with The University of Tokyo, Kyushu University, and Okayama University, have developed a nanocellulose paper semiconductor that provides both nano−micro−macro trans-scale designability of the 3D structures and wide tunability of the electrical properties. Their findings are published in ACS Nano.

Cellulose is a natural and easy to source material derived from wood. Cellulose nanofibers (nanocellulose) can be made into sheets of flexible nanocellulose paper (nanopaper) with dimensions like those of standard A4. Nanopaper does not conduct an electric current; however, heating can introduce conducting properties. Unfortunately, this exposure to heat can also disrupt the nanostructure.

The researchers have therefore devised a treatment process that allows them to heat the nanopaper without damaging the structures of the paper from the nanoscale up to the macroscale.

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Caption: Schematic diagram of the preparation of the wood nanocellulose-derived nano-semiconductor with customizable electrical properties and 3D structures Credit: 2022 Koga et al. Nanocellulose paper semiconductor with a 3D network structure and its nano−micro−macro trans-scale design. ACS Nano

An April 28, 2022 Osaka University news release (also on EurekAlert), which originated the news item, provides more detail about the work

“An important property for the nanopaper semiconductor is tunability because this allows devices to be designed for specific applications,” explains study author Hirotaka Koga. “We applied an iodine treatment that was very effective for protecting the nanostructure of the nanopaper. Combining this with spatially controlled drying meant that the pyrolysis treatment did not substantially alter the designed structures and the selected temperature could be used to control the electrical properties.”

The researchers used origami (paper folding) and kirigami (paper cutting) techniques to provide playful examples of the flexibility of the nanopaper at the macrolevel. A bird and box were folded, shapes including an apple and snowflake were punched out, and more intricate structures were produced by laser cutting. This demonstrated the level of detail possible, as well as the lack of damage caused by the heat treatment.

Examples of successful applications showed nanopaper semiconductor sensors incorporated into wearable devices to detect exhaled moisture breaking through facemasks and moisture on the skin. The nanopaper semiconductor was also used as an electrode in a glucose biofuel cell and the energy generated lit a small bulb.

“The structure maintenance and tunability that we have been able to show is very encouraging for the translation of nanomaterials into practical devices,” says Associate Professor Koga. “We believe that our approach will underpin the next steps in sustainable electronics made entirely from plant materials.”

…

About Osaka University

Osaka University was founded in 1931 as one of the seven imperial universities of Japan and is now one of Japan’s leading comprehensive universities with a broad disciplinary spectrum. This strength is coupled with a singular drive for innovation that extends throughout the scientific process, from fundamental research to the creation of applied technology with positive economic impacts. Its commitment to innovation has been recognized in Japan and around the world, being named Japan’s most innovative university in 2015 (Reuters 2015 Top 100) and one of the most innovative institutions in the world in 2017 (Innovative Universities and the Nature Index Innovation 2017). Now, Osaka University is leveraging its role as a Designated National University Corporation selected by the Ministry of Education, Culture, Sports, Science and Technology to contribute to innovation for human welfare, sustainable development of society, and social transformation.

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

Nanocellulose Paper Semiconductor with a 3D Network Structure and Its Nano–Micro–Macro Trans-Scale Design by Hirotaka Koga, Kazuki Nagashima, Koichi Suematsu, Tsunaki Takahashi, Luting Zhu, Daiki Fukushima, Yintong Huang, Ryo Nakagawa, Jiangyang Liu, Kojiro Uetani, Masaya Nogi, Takeshi Yanagida, and Yuta Nishina. ACS Nano 2022, XXXX, XXX, XXX-XXX DOI: https://doi.org/10.1021/acsnano.1c10728 Publication Date:April 26, 2022 © 2022 The Authors. Published by American Chemical Society

The paper appears to be open access.

Put a ring on it: preventing clumps of gold nanoparticles

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Caption: A comparison of how linear PEG (left) and cyclic PEG (right) attach to a gold nanoparticle Credit: Yubo Wang, Takuya Yamamoto

A January 20, 2021 news item on phys.org focuses on work designed to stop gold nanoparticles from clumping together (Note: A link has been removed),

Hokkaido University scientists have found a way to prevent gold nanoparticles from clumping, which could help towards their use as an anti-cancer therapy.

Attaching ring-shaped synthetic compounds to gold nanoparticles helps them retain their essential light-absorbing properties, Hokkaido University researchers report in the journal Nature Communications.

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A January 20, 2021 Hokkaido University press release (also on EurekAlert but published Jan. 21, 2020), which originated the news item, elaborates on the work,

Metal nanoparticles have unique light-absorbing properties, making them interesting for a wide range of optical, electronic and biomedical applications. For example, if delivered to a tumour, they could react with applied light to kill cancerous tissue. A problem with this approach, though, is that they easily clump together in solution, losing their ability to absorb light. This clumping happens in response to a variety of factors, including temperature, salt concentration and acidity.

Scientists have been trying to find ways to ensure nanoparticles stay dispersed in their target environments. Covering them with polyethylene glycol, otherwise known as PEG, has been relatively successful at this in the case of gold nanoparticles. PEG is biocompatible and can prevent gold surfaces from clumping together in the laboratory and in living organisms, but improvements are still needed.

Applied chemist Takuya Yamamoto and colleagues at Hokkaido University, The University of Tokyo, and Tokyo Institute of Technology found that mixing gold nanoparticles with ring-shaped PEG, rather than the normally linear PEG, significantly improved dispersion. The ‘cyclic-PEG’ (c-PEG) attaches to the surfaces of the nanoparticles without forming chemical bonds with them, a process called physisorption. The coated nanoparticles remained dispersed when frozen, freeze-dried and heated.

The team tested the c-PEG-covered gold nanoparticles in mice and found that they cleared slowly from the blood and accumulated better in tumours compared to gold nanoparticles coated with linear PEG. However, accumulation was lower than desired levels, so the researchers recommend further investigations to fine-tune the nanoparticles for this purpose.

Associate Professor Takuya Yamamoto is part of the Laboratory of Chemistry of Molecular Assemblies at Hokkaido University, where he studies the properties and applications of various cyclic chemical compounds.

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

Enhanced dispersion stability of gold nanoparticles by the physisorption of cyclic poly(ethylene glycol) by Yubo Wang, Jose Enrico Q. Quinsaat, Tomoko Ono, Masatoshi Maeki, Manabu Tokeshi, Takuya Isono, Kenji Tajima, Toshifumi Satoh, Shin-ichiro Sato, Yutaka Miura & Takuya Yamamoto. Nature Communications volume 11, Article number: 6089 (2020) DOI: https://doi.org/10.1038/s41467-020-19947-8 Published: 30 November 2020

This paper is open access.

A quantum phenomenon (Kondo effect) and nanomaterials

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This is a little outside my comfort zone but here goes anyway. From a December 23, 2020 news item on phys.org (Note: Links have been removed),

Osaka City University scientists have developed mathematical formulas to describe the current and fluctuations of strongly correlated electrons in quantum dots. Their theoretical predictions could soon be tested experimentally.

Theoretical physicists Yoshimichi Teratani and Akira Oguri of Osaka City University, and Rui Sakano of the University of Tokyo have developed mathematical formulas that describe a physical phenomenon happening within quantum dots and other nanosized materials. The formulas, published in the journal Physical Review Letters, could be applied to further theoretical research about the physics of quantum dots, ultra-cold atomic gasses, and quarks.

At issue is the Kondo effect. This effect was first described in 1964 by Japanese theoretical physicist Jun Kondo in some magnetic materials, but now appears to happen in many other systems, including quantum dots and other nanoscale materials.

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A December 23, 2020 Osaka City University press release (also on EurekAlert), which originated the news item, provides more detail,

Normally, electrical resistance drops in metals as the temperature drops. But in metals containing magnetic impurities, this only happens down to a critical temperature, beyond which resistance rises with dropping temperatures.

Scientists were eventually able to show that, at very low temperatures near absolute zero, electron spins become entangled with the magnetic impurities, forming a cloud that screens their magnetism. The cloud’s shape changes with further temperature drops, leading to a rise in resistance. This same effect happens when other external ‘perturbations’, such as a voltage or magnetic field, are applied to the metal. 

Teratani, Sakano and Oguri wanted to develop mathematical formulas to describe the evolution of this cloud in quantum dots and other nanoscale materials, which is not an easy task. 

To describe such a complex quantum system, they started with a system at absolute zero where a well-established theoretical model, namely Fermi liquid theory, for interacting electrons is applicable. They then added a ‘correction’ that describes another aspect of the system against external perturbations. Using this technique, they wrote formulas describing electrical current and its fluctuation through quantum dots. 

Their formulas indicate electrons interact within these systems in two different ways that contribute to the Kondo effect. First, two electrons collide with each other, forming well-defined quasiparticles that propagate within the Kondo cloud. More significantly, an interaction called a three-body contribution occurs. This is when two electrons combine in the presence of a third electron, causing an energy shift of quasiparticles. 

“The formulas’ predictions could soon be investigated experimentally”, Oguri says. “Studies along the lines of this research have only just begun,” he adds. 

The formulas could also be extended to understand other quantum phenomena, such as quantum particle movement through quantum dots connected to superconductors. Quantum dots could be a key for realizing quantum information technologies, such as quantum computers and quantum communication.

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

Fermi Liquid Theory for Nonlinear Transport through a Multilevel Anderson Impurity by Yoshimichi Teratani, Rui Sakano, and Akira Oguri. Phys. Rev. Lett. 125, 216801 (Issue Vol. 125, Iss. 21 — 20 November 2020) DOI: https://doi.org/10.1103/PhysRevLett.125.216801 Published Online: 17 November 2020

This paper is behind a paywall.

Quantum processor woven from light

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Weaving a quantum processor from light is a jaw-dropping event (as far as I’m concerned). An October 17, 2019 news item on phys.org makes the announcement,

An international team of scientists from Australia, Japan and the United States has produced a prototype of a large-scale quantum processor made of laser light.

Based on a design ten years in the making, the processor has built-in scalability that allows the number of quantum components—made out of light—to scale to extreme numbers. The research was published in Science today [October 18, 2019; Note: I cannot explain the discrepancy between the dates]].

Quantum computers promise fast solutions to hard problems, but to do this they require a large number of quantum components and must be relatively error free. Current quantum processors are still small and prone to errors. This new design provides an alternative solution, using light, to reach the scale required to eventually outperform classical computers on important problems.

…

Caption: The entanglement structure of a large-scale quantum processor made of light. Credit: Shota Yokoyama 2019

An October 18, 2019 RMIT University (Australia) press release (also on EurekAlert but published October 17, 2019), which originated the news time, expands on the theme,

“While today’s quantum processors are impressive, it isn’t clear if the current designs can be scaled up to extremely large sizes,” notes Dr Nicolas Menicucci, Chief Investigator at the Centre for Quantum Computation and Communication Technology (CQC2T) at RMIT University in Melbourne, Australia.

“Our approach starts with extreme scalability – built in from the very beginning – because the processor, called a cluster state, is made out of light.”

Using light as a quantum processor

A cluster state is a large collection of entangled quantum components that performs quantum computations when measured in a particular way.

“To be useful for real-world problems, a cluster state must be both large enough and have the right entanglement structure. In the two decades since they were proposed, all previous demonstrations of cluster states have failed on one or both of these counts,” says Dr Menicucci. “Ours is the first ever to succeed at both.”

To make the cluster state, specially designed crystals convert ordinary laser light into a type of quantum light called squeezed light, which is then weaved into a cluster state by a network of mirrors, beamsplitters and optical fibres.

The team’s design allows for a relatively small experiment to generate an immense two-dimensional cluster state with scalability built in. Although the levels of squeezing – a measure of quality – are currently too low for solving practical problems, the design is compatible with approaches to achieve state-of-the-art squeezing levels.

The team says their achievement opens up new possibilities for quantum computing with light.

“In this work, for the first time in any system, we have made a large-scale cluster state whose structure enables universal quantum computation.” Says Dr Hidehiro Yonezawa, Chief Investigator, CQC2T at UNSW Canberra. “Our experiment demonstrates that this design is feasible – and scalable.”

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The experiment was an international effort, with the design developed through collaboration by Dr Menicucci at RMIT, Dr Rafael Alexander from the University of New Mexico and UNSW Canberra researchers Dr Hidehiro Yonezawa and Dr Shota Yokoyama. A team of experimentalists at the University of Tokyo, led by Professor Akira Furusawa, performed the ground-breaking experiment.

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

Generation of time-domain-multiplexed two-dimensional cluster state by Warit Asavanant, Yu Shiozawa, Shota Yokoyama, Baramee Charoensombutamon, Hiroki Emura, Rafael N. Alexander, Shuntaro Takeda, Jun-ichi Yoshikawa, Nicolas C. Menicucci, Hidehiro Yonezawa, Akira Furusawa. Science 18 Oct 2019: Vol. 366, Issue 6463, pp. 373-376 DOI: 10.1126/science.aay2645

This paper is behind a paywall.

AI (artificial intelligence) for Good Global Summit from May 15 – 17, 2018 in Geneva, Switzerland: details and an interview with Frederic Werner

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With all the talk about artificial intelligence (AI), a lot more attention seems to be paid to apocalyptic scenarios: loss of jobs, financial hardship, loss of personal agency and privacy, and more with all of these impacts being described as global. Still, there are some folks who are considering and working on ‘AI for good’.

If you’d asked me, the International Telecommunications Union (ITU) would not have been my first guess (my choice would have been United Nations Educational, Scientific and Cultural Organization [UNESCO]) as an agency likely to host the 2018 AI for Good Global Summit. But, it turns out the ITU is a UN (United Nations agency) and, according to its Wikipedia entry, it’s an intergovernmental public-private partnership, which may explain the nature of the participants in the upcoming summit.

The news

First, there’s a May 4, 2018 ITU media advisory (received via email or you can find the full media advisory here) about the upcoming summit,

Artificial Intelligence (AI) is now widely identified as being able to address the greatest challenges facing humanity – supporting innovation in fields ranging from crisis management and healthcare to smart cities and communications networking.

The second annual ‘AI for Good Global Summit’ will take place 15-17 May [2018] in Geneva, and seeks to leverage AI to accelerate progress towards the United Nations’ Sustainable Development Goals and ultimately benefit humanity.

WHAT: Global event to advance ‘AI for Good’ with the participation of internationally recognized AI experts. The programme will include interactive high-level panels, while ‘AI Breakthrough Teams’ will propose AI strategies able to create impact in the near term, guided by an expert audience of mentors representing government, industry, academia and civil society – through interactive sessions. The summit will connect AI innovators with public and private-sector decision-makers, building collaboration to take promising strategies forward.

A special demo & exhibit track will feature innovative applications of AI designed to: protect women from sexual violence, avoid infant crib deaths, end child abuse, predict oral cancer, and improve mental health treatments for depression – as well as interactive robots including: Alice, a Dutch invention designed to support the aged; iCub, an open-source robot; and Sophia, the humanoid AI robot.

WHEN: 15-17 May 2018, beginning daily at 9 AM

WHERE: ITU Headquarters, 2 Rue de Varembé, Geneva, Switzerland (Please note: entrance to ITU is now limited for all visitors to the Montbrillant building entrance only on rue Varembé).

WHO: Confirmed participants to date include expert representatives from: Association for Computing Machinery, Bill and Melinda Gates Foundation, Cambridge University, Carnegie Mellon, Chan Zuckerberg Initiative, Consumer Trade Association, Facebook, Fraunhofer, Google, Harvard University, IBM Watson, IEEE, Intellectual Ventures, ITU, Microsoft, Massachusetts Institute of Technology (MIT), Partnership on AI, Planet Labs, Shenzhen Open Innovation Lab, University of California at Berkeley, University of Tokyo, XPRIZE Foundation, Yale University – and the participation of “Sophia” the humanoid robot and “iCub” the EU open source robotcub.

The interview

Frederic Werner, Senior Communications Officer at the International Telecommunication Union and** one of the organizers of the AI for Good Global Summit 2018 kindly took the time to speak to me and provide a few more details about the upcoming event.

Werner noted that the 2018 event grew out of a much smaller 2017 ‘workshop’ and first of its kind, about beneficial AI which this year has ballooned in size to 91 countries (about 15 participants are expected from Canada), 32 UN agencies, and substantive representation from the private sector. The 2017 event featured Dr. Yoshua Bengio of the University of Montreal  (Université de Montréal) was a featured speaker.

“This year, we’re focused on action-oriented projects that will help us reach our Sustainable Development Goals (SDGs) by 2030. We’re looking at near-term practical AI applications,” says Werner. “We’re matchmaking problem-owners and solution-owners.”

Academics, industry professionals, government officials, and representatives from UN agencies are gathering  to work on four tracks/themes:

  • ​AI and satellite imagery
  • AI and health
  • AI ​and smart cities & communities
  • Trust in AI

In advance of this meeting, the group launched an AI repository (an action item from the 2017 meeting) on April 25, 2018 inviting people to list their AI projects (from the ITU’s April 25, 2018? AI repository news announcement),

ITU has just launched an AI Repository where anyone working in the field of artificial intelligence (AI) can contribute key information about how to leverage AI to help solve humanity’s greatest challenges.

This is the only global repository that identifies AI-related projects, research initiatives, think-tanks and organizations that aim to accelerate progress on the 17 United Nations’ Sustainable Development Goals (SDGs).

To submit a project, just press ‘Submit’ on the AI Repository site and fill in the online questionnaire, providing all relevant details of your project. You will also be asked to map your project to the relevant World Summit on the Information Society (WSIS) action lines and the SDGs. Approved projects will be officially registered in the repository database.

Benefits of participation on the AI Repository include:

WSIS Prizes recognize individuals, governments, civil society, local, regional and international agencies, research institutions and private-sector companies for outstanding success in implementing development oriented strategies that leverage the power of AI and ICTs.

Creating the AI Repository was one of the action items of last year’s AI for Good Global Summit.

We are looking forward to your submissions.

If you have any questions, please send an email to: ai@itu.int

“Your project won’t be visible immediately as we have to vet the submissions to weed out spam-type material and projects that are not in line with our goals,” says Werner. That said, there are already 29 projects in the repository. As you might expect, the UK, China, and US are in the repository but also represented are Egypt, Uganda, Belarus, Serbia, Peru, Italy, and other countries not commonly cited when discussing AI research.

Werner also pointed out in response to my surprise over the ITU’s role with regard to this AI initiative that the ITU is the only UN agency which has 192* member states (countries), 150 universities, and over 700 industry members as well as other member entities, which gives them tremendous breadth of reach. As well, the organization, founded originally in 1865 as the International Telegraph Convention, has extensive experience with global standardization in the information technology and telecommunications industries. (See more in their Wikipedia entry.)

Finally

There is a bit more about the summit on the ITU’s AI for Good Global Summit 2018 webpage,

The 2nd edition of the AI for Good Global Summit will be organized by ITU in Geneva on 15-17 May 2018, in partnership with XPRIZE Foundation, the global leader in incentivized prize competitions, the Association for Computing Machinery (ACM) and sister United Nations agencies including UNESCO, UNICEF, UNCTAD, UNIDO, Global Pulse, UNICRI, UNODA, UNIDIR, UNODC, WFP, IFAD, UNAIDS, WIPO, ILO, UNITAR, UNOPS, OHCHR, UN University, WHO, UNEP, ICAO, UNDP, The World Bank, UN DESA, CTBTO, UNISDR, UNOG, UNOOSA, UNFPA, UNECE, UNDPA, and UNHCR.

The AI for Good series is the leading United Nations platform for dialogue on AI. The action​​-oriented 2018 summit will identify practical applications of AI and supporting strategies to improve the quality and sustainability of life on our planet. The summit will continue to formulate strategies to ensure trusted, safe and inclusive development of AI technologies and equitable access to their benefits.

While the 2017 summit sparked the first ever inclusive global dialogue on beneficial AI, the action-oriented 2018 summit will focus on impactful AI solutions able to yield long-term benefits and help achieve the Sustainable Development Goals. ‘Breakthrough teams’ will demonstrate the potential of AI to map poverty and aid with natural disasters using satellite imagery, how AI could assist the delivery of citizen-centric services in smart cities, and new opportunities for AI to help achieve Universal Health Coverage, and finally to help achieve transparency and explainability in AI algorithms.

Teams will propose impactful AI strategies able to be enacted in the near term, guided by an expert audience of mentors representing government, industry, academia and civil society. Strategies will be evaluated by the mentors according to their feasibility and scalability, potential to address truly global challenges, degree of supporting advocacy, and applicability to market failures beyond the scope of government and industry. The exercise will connect AI innovators with public and private-sector decision-makers, building collaboration to take promising strategies forward.

“As the UN specialized agency for information and communication technologies, ITU is well placed to guide AI innovation towards the achievement of the UN Sustainable Development ​Goals. We are providing a neutral close quotation markplatform for international dialogue aimed at ​building a ​common understanding of the capabilities of emerging AI technologies.​​” Houlin Zhao, Secretary General ​of ITU​

Should you be close to Geneva, it seems that registration is still open. Just go to the ITU’s AI for Good Global Summit 2018 webpage, scroll the page down to ‘Documentation’ and you will find a link to the invitation and a link to online registration. Participation is free but I expect that you are responsible for your travel and accommodation costs.

For anyone unable to attend in person, the summit will be livestreamed (webcast in real time) and you can watch the sessions by following the link below,

https://www.itu.int/en/ITU-T/AI/2018/Pages/webcast.aspx

For those of us on the West Coast of Canada and other parts distant to Geneva, you will want to take the nine hour difference between Geneva (Switzerland) and here into account when viewing the proceedings. If you can’t manage the time difference, the sessions are being recorded and will be posted at a later date.

*’132 member states’ corrected to ‘192 member states’ on May 11, 2018 at 1500 hours PDT.

*Redundant ‘and’ removed on July 19, 2018.