Scientists used equipment at the Canadian Light Source (CLS; synchrotron in Saskatoon, Saskatchewan, Canada) in the quest for better glowing dots on your television (maybe computers and telephones, too?) screen. From an August 20, 2020 news item on Nanowerk,
There are many things quantum dots could do, but the most obvious place they could change our lives is to make the colours on our TVs and screens more pristine. Research using the Canadian Light Source (CLS) at the University of Saskatchewan is helping to bring this technology closer to our living rooms.
An August 19, 2020 CLS news release (also received via email) by Victoria Martinez, which originated the news item, explains what quantum dots are and fills in with technical details about this research,
Quantum dots are nanocrystals that glow, a property that scientists have been working with to develop next-generation LEDs. When a quantum dot glows, it creates very pure light in a precise wavelength of red, blue or green. Conventional LEDs, found in our TV screens today, produce white light that is filtered to achieve desired colours, a process that leads to less bright and muddier colours.
Until now, blue-glowing quantum dots, which are crucial for creating a full range of colour, have proved particularly challenging for researchers to develop. However, University of Toronto (U of T) researcher Dr. Yitong Dong and collaborators have made a huge leap in blue quantum dot fluorescence, results they recently published in Nature Nanotechnology.
“The idea is that if you have a blue LED, you have everything. We can always down convert the light from blue to green and red,” says Dong. “Let’s say you have green, then you cannot use this lower-energy light to make blue.”
The team’s breakthrough has led to quantum dots that produce green light at an external quantum efficiency (EQE) of 22% and blue at 12.3%. The theoretical maximum efficiency is not far off at 25%, and this is the first blue perovskite LED reported as achieving an EQE higher than 10%.
Dong has been working in the field of quantum dots for two years in Dr. Edward Sargent’s research group at the U of T. This astonishing increase in efficiency took time, an unusual production approach, and overcoming several scientific hurdles to achieve.
CLS techniques, particularly GIWAXS [grazing incidence wide-angle X-ray scattering] on the HXMA beamline [hard X-ray micro-analysis (HXMA)], allowed the researchers to verify the structures achieved in their quantum dot films. This validated their results and helped clarify what the structural changes achieve in terms of LED performance.
“The CLS was very helpful. GIWAXS is a fascinating technique,” says Dong.
The first challenge was uniformity, important to ensuring a clear blue colour and to prevent the LED from moving towards producing green light.
“We used a special synthetic approach to achieve a very uniform assembly, so every single particle has the same size and shape. The overall film is nearly perfect and maintains the blue emission conditions all the way through,” says Dong.
Next, the team needed to tackle the charge injection needed to excite the dots into luminescence. Since the crystals are not very stable, they need stabilizing molecules to act as scaffolding and support them. These are typically long molecule chains, with up to 18 carbon-non-conductive molecules at the surface, making it hard to get the energy to produce light.
“We used a special surface structure to stabilize the quantum dot. Compared to the films made with long chain molecules capped quantum dots, our film has 100 times higher conductivity, sometimes even 1000 times higher.”
This remarkable performance is a key benchmark in bringing these nanocrystal LEDs to market. However, stability remains an issue and quantum dot LEDs suffer from short lifetimes. Dong is excited about the potential for the field and adds, “I like photons, these are interesting materials, and, well, these glowing crystals are just beautiful.”
Here’s a link to and a citation for the paper,
Bipolar-shell resurfacing for blue LEDs based on strongly confined perovskite quantum dots by Yitong Dong, Ya-Kun Wang, Fanglong Yuan, Andrew Johnston, Yuan Liu, Dongxin Ma, Min-Jae Choi, Bin Chen, Mahshid Chekini, Se-Woong Baek, Laxmi Kishore Sagar, James Fan, Yi Hou, Mingjian Wu, Seungjin Lee, Bin Sun, Sjoerd Hoogland, Rafael Quintero-Bermudez, Hinako Ebe, Petar Todorovic, Filip Dinic, Peicheng Li, Hao Ting Kung, Makhsud I. Saidaminov, Eugenia Kumacheva, Erdmann Spiecker, Liang-Sheng Liao, Oleksandr Voznyy, Zheng-Hong Lu, Edward H. Sargent. Nature Nanotechnology volume 15, pages668–674(2020) DOI: https://doi.org/10.1038/s41565-020-0714-5 Published: 06 July 2020 Issue Date: August 2020
This paper is behind a paywall.
If you search “Edward Sargent,” he’s the last author listed in the citation, here on this blog, you will find a number of postings that feature work from his laboratory at the University of Toronto.
I was half-expecting to read about some sort of fancy carbon nanotubes—I was wrong. From an August 12, 2020 news item on ScienceDaily where the researchers keep the mystery going for a while,
A new mechanism of blood redistribution that is essential for the proper functioning of the adult retina has just been discovered in vivo by researchers at the University of Montreal Hospital Research Centre (CRCHUM).
“For the first time, we have identified a communication structure between cells that is required to coordinate blood supply in the living retina,” said Dr. Adriana Di Polo, a neuroscience professor at Université de Montréal and holder of a Canada Research Chair in glaucoma and age-related neurodegeneration, who supervised the study.
“We already knew that activated retinal areas receive more blood than non-activated ones,” she said, “but until now no one understood how this essential blood delivery was finely regulated.”
The study was conducted on mice by two members of Di Polo’s lab: Dr. Luis Alarcon-Martinez, a postdoctoral fellow, and Deborah Villafranca-Baughman, a PhD student. Both are the first co-authors of this study.
In living animals, as in humans, the retina uses the oxygen and nutrients contained in the blood to fully function. This vital exchange takes place through capillaries, the thinnest blood vessels in all organs of the body. When the blood supply is dramatically reduced or cut off — such as in ischemia or stroke — the retina does not receive the oxygen it needs. In this condition, the cells begin to die and the retina stops working as it should.
Wrapped around the capillaries are pericytes, cells that have the ability to control the amount of blood passing through a single capillary simply by squeezing and releasing it.
“Using a microscopy technique to visualize vascular changes in living mice, we showed that pericytes project very thin tubes, called inter-pericyte tunnelling nanotubes, [emphasis mine] to communicate with other pericytes located in distant capillaries,” said Alarcon-Martinez. “Through these nanotubes, the pericytes can talk to each other to deliver blood where it is most needed.”
Another important feature, added Villafranca-Baughman, is that “the capillaries lose their ability to shuttle blood where it is required when the tunnelling nanotubes are damaged–after an ischemic stroke, for example. The lack of blood supply that follows has a detrimental effect on neurons and the overall tissue function.”
The team’s findings suggest that microvascular deficits observed in neurodegenerative diseases like strokes, glaucoma, and Alzheimer’s disease might result from the loss of tunnelling nanotubes and impaired blood distribution. Strategies that protect these nanostructures should then be beneficial, but remain to be demonstrated.
Here’s a link to and a citation for the paper
Interpericyte tunnelling nanotubes regulate neurovascular coupling by Luis Alarcon-Martinez, Deborah Villafranca-Baughman, Heberto Quintero, J. Benjamin Kacerovsky, Florence Dotigny, Keith K. Murai, Alexandre Prat, Pierre Drapeau & Adriana Di Polo. Nature (2020) Published: 12 August 2020 DOI: https://doi.org/10.1038/s41586-020-2589-x
A new class of nanosensor developed in Brazil could more accurately identify dengue and Zika infections, a task that is complicated by their genetic similarities and which can result in misdiagnosis.
The technique uses gold nanoparticles and can “observe” viruses at the atomic level, according to a study published in Scientific Reports (“Nanosensors based on LSPR are able to serologically differentiate dengue from Zika infections”).
Belonging to the Flavivirus genus in the Flaviviridae family, Zika and dengue viruses share more than 50 per cent similarity in their amino acid sequence. Both viruses are spread by mosquitos and can have long-term side effects. The Flaviviridae virus family was named after the yellow fever virus and comes from the Latin word for golden, or yellow, in colour.
“Diagnosing [dengue virus] infections is a high priority in countries affected by annual epidemics of dengue fever. The correct diagnostic is essential for patient managing and prognostic as there are no specific antiviral drugs to treat the infection,” the authors say.
More than 1.8 million people are suspected to have been infected with dengue so far this year in the Americas, with 4000 severe cases and almost 700 deaths, the Pan American Health Organization says. The annual global average is estimated to be between 100 million and 400 million dengue infections, according to the World Health Organization.
Flávio Fonseca, study co-author and researcher at the Federal University of Minas Gerais, tells SciDev.Net it is almost impossible to differentiate between dengue and Zika viruses.
“A serologic test that detects antibodies against dengue also captures Zika-generated antibodies. We call it cross-reactivity,” he says.
Meghie Rodrigues’ July 29, 2020 article for SciDev.net, which originated the news item, delves further into the work,
Co-author and virologist, Maurício Nogueira, tells SciDev.Net that avoiding cross-reactivity is crucial because “dengue is a disease that kills — and can do so quickly if the right diagnosis is not made. As for Zika, it offers risks for foetuses to develop microcephaly, and we can’t let pregnant women spend seven or eight months wondering whether they have the virus or not.”
There is also no specific antiviral treatment for Zika and the search for a vaccine is ongoing.
Virus differentiation is important to accurately measure the real impact of both diseases on public health. The most widely used blood test, the enzyme-linked immunosorbent assay (ELISA), is limited in its ability to tell the difference between the viruses, the authors say.
As dengue has four variations, known as serotypes, the team created four different nanoparticles and covered each of them with a different dengue protein. They applied ELISA serum and a blood sample. The researchers found that sample antibodies bound with the viruses’ proteins, changing the pattern of electrons on the gold nanoparticle surface.
Should you check out Rodrigues’ entire article, you might want to take some time to explore SciDev.net to find science news from countries that don’t often get the coverage they should.
Here’s a link to and a citation for the researchers’ paper,
I always enjoy the unexpected in a story and this one has to do with plantains and luxury cars, from a July 29, 2020 news item on phys.org (Note: A link has been removed),
A luxury automobile is not really a place to look for something like sisal, hemp, or wood. Yet automakers have been using natural fibers for decades. Some high-end sedans and coupes use these in composite materials for interior door panels, for engine, interior and noise insulation, and internal engine covers, among other uses.
Unlike steel or aluminum, natural fiber composites do not rust or corrode. They can also be durable and easily molded. The biggest advantages of fiber reinforced polymer composites for cars are light weight, good crash properties, and noise- and vibration-reducing characteristics. But making more parts of a vehicle from renewable sources is a challenge. Natural fiber polymer composites can crack, break and bend. The reasons include low tensile, flexural and impact strength in the composite material.
Researchers from the University of Johannesburg [South Africe] have now demonstrated that plantain, a starchy type of banana, is a promising source for an emerging type of composite material for the automotive industry. The natural plantain fibers are combined with carbon nanotubes and epoxy resin to form a natural fiber-reinforced polymer hybrid nanocomposite material. Plantain is a year-round staple food crop in tropical regions of Africa, Asia and South America. Many types of plantain are eaten cooked.
Plantain is a year-round staple food crop in tropical regions of Africa, Asia and South America. Many types of plantain are eaten cooked.
The researchers moulded a composite material from epoxy resin, treated plantain fibers and carbon nanotubes. The optimum amount of nanotubes was 1% by weight of the plantain-epoxy resin combined.
The resulting plantain nanocomposite was much stronger and stiffer than epoxy resin on its own.
The composite had 31% more tensile and 34% more flexural strength than the epoxy resin alone. The nanocomposite also had 52% higher tensile modulus and 29% higher flexural modulus than the epoxy resin alone.
“The hybridization of plantain with multi-walled carbon nanotubes increases the mechanical and thermal strength of the composite. These increases make the hybrid composite a competitive and alternative material for certain car parts,” says Prof Tien-Chien Jen.
Prof Jen is the lead researcher in the study and the Head of the Department of Mechanical Engineering Science at the University of Johannesburg.
Natural fibres vs metals
Producing car parts from renewable sources have several benefits, says Dr Patrick Ehi Imoisili. Dr Imoisili is a postdoctoral researcher in the Department of Mechanical Engineering Science at the University of Johannesburg.
“There is a trend of using natural fibre in vehicles. The reason is that natural fibres composites are renewable, low cost and low density. They have high specific strength and stiffness. The manufacturing processes are relatively safe,” says Imoisili.
“Using car parts made from these composites, can reduce the mass of a vehicle. That can result in better fuel-efficiency and safety. These components will not rust or corrode like metals. Also, they can be stiff, durable and easily molded,” he adds.
However, some natural fibre reinforced polymer composites currently have disadvantages such as water absorption, low impact strength and low heat resistance. Car owners can notice effects such as cracking, bending or warping of a car part, says Imoisili.
The researchers subjected the plantain nanocomposite to a series of standardised industrial tests. These included ASTM Test Methods D638 and D790; impact testing according to the ASTM A-370 standard; and ASTM D-2240.
The tests showed that a composite with 1% nanotubes had the best strength and stiffness, compared to epoxy resin alone.
The plantain nanocomposite also showed marked improvement in micro hardness, impact strength and thermal conductivity compared to epoxy resin alone.
Moulding a nanocomposite from natural fibres
The researchers compression-moulded a ‘stress test object’. They used 1 part inedible plantain fibres, 4 parts epoxy resin and multi-walled carbon nanotubes. The epoxy resin and nanotubes came from commercial suppliers. The epoxy was similar to resins that auto manufacturers use in certain car parts.
The plantain fibres came from the ‘trunks’ or pseudo-stems, of plantain plants in the south-western region of Nigeria. The pseudo-stems consist of tightly-overlapping leaves.
The researchers treated the plantain fibers with several processes. The first process is an ancient method to separate plant fibres from stems, called water-retting.
In the second process, the fibres were soaked in a 3% caustic soda solution for 4 hours. After drying, the fibres were treated with high-frequency microwave radiation of 2.45GHz at 550W for 2 minutes.
The caustic soda and microwave treatments improved the bonding between the plantain fibers and the epoxy resin in the nanocomposite.
Next, the researchers dispersed the nanotubes in ethanol to prevent ‘bunching’ of the tubes in the composite. After that, the plantain fibres, nanotubes and epoxy resin were combined inside a mold. The mold was then compressed with a load for 24 hours at room temperature.
Food crop vs industrial raw material
Plantain is grown in tropical regions worldwide. This includes Mexico, Florida and Texas in North America; Brazil, Honduras, Guatemala in South and Central America; India, China, and Southeast Asia.
In West and Central Africa, farmers grow plantain in Cameroon, Ghana, Uganda, Rwanda, Nigeria, Cote d’Ivoire and Benin.
Using biomass from major staple food crops can create problems in food security for people with low incomes. In addition, the automobile industry will need access to reliable sources of natural fibres to increase use of natural fibre composites.
In the case of plantains, potential tensions between food security and industrial uses for composite materials are low. This is because plantain farmers discard the pseudo-stems as agro-waste after harvest.
The night sky has inspired speculation, discovery, and stories throughout time and from all the peoples of this planet. The information derived from observing the stars and moon has led to voyages on land, on sea, through space, and into the recesses of minds and hearts.
Currently, an ancient celestial practice, celebration of solstices and equinoxes seems to be gaining popularity and acceptance.
Indigenous Star Knowledge Symposia: A series of local and international gatherings, on the land and online
Organised by Ingenium in collaboration with the Institute of Indigenous Research and Studies at the University of Ottawa, and hosted on traditional Algonquin Anishnaabeg territory, this series of symposia (chosen on the dates of the Fall equinox, Winter solstice, Spring equinoxes and Summer solstice) will combine spiritual ceremony, presentations, activities and dialogue, both online and on the land. The symposia will feature gatherings of Indigenous Knowledge Keepers, Elders, educators and scholars to share and exchange towards reclaiming, preserving, and revitalizing Star Knowledge with Indigenous communities worldwide.
Our original plan was to have a symposium in September 2020, but due to Covid-19 we have reshaped the entire program to spread out the timeline while combining physical and digitally-inclusive experiences. This blended format greatly expands our original intent to offer a space for teaching and learning, while bringing hope and healing through the Indigenous Star Knowledge and our work.
Fall Equinox: Protocols before Knowledge, Seasonal and regional themes
September 21, 2020 (7 p.m. Est Ottawa, Canada); September 22, 2020 (9:00 a.m. Lismore, Australia)
For Indigenous people astronomy and cosmology are intricately intertwined. Star Knowledge, like everything else, is all about relationships and teaches us our place in the universe.
Shawn Wilson is Opaskwayak Cree from Manitoba. He works at Gnibi College of Indigenous Australian Peoples and is also an Adjunct Professor at Østfold University College in Norway. Shawn will discuss how understanding Indigenous Star Knowledge develops a deeper understanding of the very nature of reality. To gain this understanding requires us to develop deeper relationships with Sky Country.
Stuart Barlo is a Yuin man from the south coast of New South Wales, and is Dean of Gnibi College of Indigenous Australian Peoples. Stuart will talk about the journey of being able to speak about Sky Country. The journey requires learning how to prepare yourself and create a safe space to develop relationship with Sky Country.
Wilfred Buck, Manitoba First Nations Education Resource Center
*Postponed and adapted due to COVID* Coinciding with a ceremony at Kitigan Zibi, Quebec to launch the Algonquin Star Knowledge Project. Offering of Tobacco and Prayer on the land with Peter Decontie, Wilfred Buck, Anita Tenasco and members of the Algonquin community.
It gets a little confusing but I gather that the symposia are linked to a larger initiative, which has its roots in a 2017 exhibition (co-curated by Wilfred Buck and Annette S. Lee) at Canada’s Science and Technology Museum,
By the way, MFNERC is Manitoba First Nations Education Resource Centre.
One Sky, Many Worlds; Indigenous Voices in Astronomy
I gather various parties have been working together to produce not only the symposia but a new traveling exhibition “One Sky, Many Worlds; Indigenous Voices in Astronomy.”
I was going to call this item a brochure but its URL includes the words “exhibition book.” Regardless, it’s where you can get more details about “One Sky, Many Worlds” and how it was developed. Do take a look at it, there are many beautiful images, including Margaret Nazon’s beadworks of art, one of which I featured at the beginning of this posting. There are many works of Indigenous astronomy-based art featured in the ‘brochure’. For some reason, the text is white against a dark background. Perhaps they were trying to evoke the stars against the night sky? Unfortunately, it makes the text less readable, which would seem to defeat the purpose of bothering with text in the first place. Also, it can lead to having to deal with cranky writers who worry their work won’t be read. (Just a thought)
New Partnership with Ingenium: Canada’s Museums of Science and Innovation
Nomad are proud to be selected as Ingenium’s partner to develop and tour an exciting new international travelling exhibition ‘One Sky, Many Worlds: Indigenous Voices in Astronomy’. This ground-breaking new exhibition will illustrate in a spectacular immersive display environment how for tens of thousands of years Indigenous people have been building a relationship with the night sky.
The exhibition will showcase artifacts representing global collections, whilst numerous mechanical and digital interactive elements will enhance visitors’ learning and understanding in an engaging, active way that reminds every human being that we come from the stars.
Led by Indigenous knowledge keepers, One Sky, Many Worlds: Indigenous Voices in Astronomy, is an 8,000 sq ft traveling exhibition that explores Indigenous Star Knowledge from locations around the globe. Featuring content from North America, South Africa, Australia, Mexico, South America, Asia, Hawaii, and New Zealand, One Sky asks questions, and shares experiences that will resonate with all people who look up and wonder about the night sky. The exhibition is available for tour internationally from summer 2021. [emphasis mine]
Nomad Exhibitions are innovative creators of international museum quality touring exhibitions.
Nomad offers a unique portfolio of high quality touring exhibitions combining curatorial excellence, state of the art design and seamless turnkey production. Our exhibitions are designed to facilitate exceptional international collaborations between cultural institutions on major exhibition projects, providing museum professionals with a tailored exhibition hosting experience.
Nomad Exhibitions is located in Edinburgh, Scotland, UK.
One Sky, Many Worlds is a collaborative exhibition led by Indigenous Knowledge Keepers, both young and old, from around the world. The exhibition explores the enduring relationship and connection that Indigenous people have with the night sky and how it has provided –and continues to provide – a practical, cultural, and spiritual guidebook for life.
One Sky, Many Worlds is, at its core, experiential. A strong emphasis on exceptional objects and intriguing ideas will be carefully complemented by a variety of interactive elements and spaces designed to engage visitors in active participation.
Each exhibition section will feature an immersive experience, audio visual content, and a selection of digital interactives, many of which will be touch free. For example, visitors will be transported from the Mississippi through the Milky Way on to the Pacific Ocean via a beautiful, [emphasis mine] immersive projection experience; visitors will be engaged in stories as told by Indigenous Elders in their own language; and visitors will also have the opportunity to participate in dynamic activities that show the links between earth and sky and allow them to see the constellations in a whole new way.
The example is a bit puzzling since ‘the Mississippi’ could mean either the ‘state of Mississippi’ or the ‘Mississippi River’ neither of which have any connection to the Pacific Ocean. But, perhaps astronomy buffs would understand this better than I do.
As to why either the state or the river would be the starting point for transportation via the Milky Way, that is a mystery. Especially after taking a look at Sharmila Kuthunu’s July 1, 2019 article, “How to See the Milky Way in 5 Easy Steps” for Space Tourism Guide,
Home to 400 billion stars, our galaxy is a barred spiral that spans 100,000 light years in diameter. While that might seem huge, the Milky Way is only clearly visible from April through October in the northern hemisphere and is hidden below the horizon for half the year.
It rises in the southeast, crosses over the horizon and sets in the southwest. Since it rises and sets in the southern hemisphere, those living in the south can see it directly overhead. The largest view of the galaxy can be seen from southern hemisphere destinations like South Africa, Chile, and Australia [emphasis mine].
Given that there was a global collaboration and the Milky Way is visible from any number of starting points, the choice of whichever Mississippi the writer intended to highlight seems odd. (See geography of Mississippi River; geography of Mississippi state [be sure to follow the red arrow to the green rectangle bordering the Gulf of Mexico])
Most likely, it’s my ignorance showing.
Plus, when I saw Nomad was offering an example, I was hoping there’d be a description or a story representing Indigenous astronomy. If you look at the brochure/exhibition book you’ll see they had a broad range of Indigenous societies represented on the team. The nomad description seems like a lost opportunity.
Regardless of my nitpicking, both the symposia and the travelling exhibition are exciting and I hope they get the attention they deserve.
If you’re as ignorant about astronomy as I am, you might find this piece about the Milky Way on the US National Aeronautics and Space Administration (NASA) website helpful.
Researchers at Stanford University (California, US) believe they have a solution for a problem with neuroprosthetics (Note: I have included brief comments about neuroprosthetics and possible ethical issues at the end of this posting) according an August 5, 2020 news item on ScienceDaily,
The current generation of neural implants record enormous amounts of neural activity, then transmit these brain signals through wires to a computer. But, so far, when researchers have tried to create wireless brain-computer interfaces to do this, it took so much power to transmit the data that the implants generated too much heat to be safe for the patient. A new study suggests how to solve his problem — and thus cut the wires.
Stanford researchers have been working for years to advance a technology that could one day help people with paralysis regain use of their limbs, and enable amputees to use their thoughts to control prostheses and interact with computers.
The team has been focusing on improving a brain-computer interface, a device implanted beneath the skull on the surface of a patient’s brain. This implant connects the human nervous system to an electronic device that might, for instance, help restore some motor control to a person with a spinal cord injury, or someone with a neurological condition like amyotrophic lateral sclerosis, also called Lou Gehrig’s disease.
The current generation of these devices record enormous amounts of neural activity, then transmit these brain signals through wires to a computer. But when researchers have tried to create wireless brain-computer interfaces to do this, it took so much power to transmit the data that the devices would generate too much heat to be safe for the patient.
Now, a team led by electrical engineers and neuroscientists Krishna Shenoy, PhD, and Boris Murmann, PhD, and neurosurgeon and neuroscientist Jaimie Henderson, MD, have shown how it would be possible to create a wireless device, capable of gathering and transmitting accurate neural signals, but using a tenth of the power required by current wire-enabled systems. These wireless devices would look more natural than the wired models and give patients freer range of motion.
Graduate student Nir Even-Chen and postdoctoral fellow Dante Muratore, PhD, describe the team’s approach in a Nature Biomedical Engineering paper.
The team’s neuroscientists identified the specific neural signals needed to control a prosthetic device, such as a robotic arm or a computer cursor. The team’s electrical engineers then designed the circuitry that would enable a future, wireless brain-computer interface to process and transmit these these carefully identified and isolated signals, using less power and thus making it safe to implant the device on the surface of the brain.
To test their idea, the researchers collected neuronal data from three nonhuman primates and one human participant in a (BrainGate) clinical trial.
As the subjects performed movement tasks, such as positioning a cursor on a computer screen, the researchers took measurements. The findings validated their hypothesis that a wireless interface could accurately control an individual’s motion by recording a subset of action-specific brain signals, rather than acting like the wired device and collecting brain signals in bulk.
The next step will be to build an implant based on this new approach and proceed through a series of tests toward the ultimate goal.
As I found out while investigating, ethical issues in this area abound. My first thought was to look at how someone with a focus on ability studies might view the complexities.
My ‘go to’ resource for human enhancement and ethical issues is Gregor Wolbring, an associate professor at the University of Calgary (Alberta, Canada). his profile lists these areas of interest: ability studies, disability studies, governance of emerging and existing sciences and technologies (e.g. neuromorphic engineering, genetics, synthetic biology, robotics, artificial intelligence, automatization, brain machine interfaces, sensors) and more.
I can’t find anything more recent on this particular topic but I did find an August 10, 2017 essay for The Conversation where he comments on technology and human enhancement ethical issues where the technology is gene-editing. Regardless, he makes points that are applicable to brain-computer interfaces (human enhancement), Note: Links have been removed),
Ability expectations have been and still are used to disable, or disempower, many people, not only people seen as impaired. They’ve been used to disable or marginalize women (men making the argument that rationality is an important ability and women don’t have it). They also have been used to disable and disempower certain ethnic groups (one ethnic group argues they’re smarter than another ethnic group) and others.
A recent Pew Research survey on human enhancement revealed that an increase in the ability to be productive at work was seen as a positive. What does such ability expectation mean for the “us” in an era of scientific advancements in gene-editing, human enhancement and robotics?
Which abilities are seen as more important than others?
The ability expectations among “us” will determine how gene-editing and other scientific advances will be used.
And so how we govern ability expectations, and who influences that governance, will shape the future. Therefore, it’s essential that ability governance and ability literacy play a major role in shaping all advancements in science and technology.
One of the reasons I find Gregor’s commentary so valuable is that he writes lucidly about ability and disability as concepts and poses what can be provocative questions about expectations and what it is to be truly abled or disabled. You can find more of his writing here on his eponymous (more or less) blog.
Ethics of clinical trials for testing brain implants
In 2003, neurologist Helen Mayberg of Emory University in Atlanta began to test a bold, experimental treatment for people with severe depression, which involved implanting metal electrodes deep in the brain in a region called area 25 [emphases mine]. The initial data were promising; eventually, they convinced a device company, St. Jude Medical in Saint Paul, to sponsor a 200-person clinical trial dubbed BROADEN.
This month [October 2017], however, Lancet Psychiatry reported the first published data on the trial’s failure. The study stopped recruiting participants in 2012, after a 6-month study in 90 people failed to show statistically significant improvements between those receiving active stimulation and a control group, in which the device was implanted but switched off.
… a tricky dilemma for companies and research teams involved in deep brain stimulation (DBS) research: If trial participants want to keep their implants [emphases mine], who will take responsibility—and pay—for their ongoing care? And participants in last week’s meeting said it underscores the need for the growing corps of DBS researchers to think long-term about their planned studies.
… participants bear financial responsibility for maintaining the device should they choose to keep it, and for any additional surgeries that might be needed in the future, Mayberg says. “The big issue becomes cost [emphasis mine],” she says. “We transition from having grants and device donations” covering costs, to patients being responsible. And although the participants agreed to those conditions before enrolling in the trial, Mayberg says she considers it a “moral responsibility” to advocate for lower costs for her patients, even it if means “begging for charity payments” from hospitals. And she worries about what will happen to trial participants if she is no longer around to advocate for them. “What happens if I retire, or get hit by a bus?” she asks.
There’s another uncomfortable possibility: that the hypothesis was wrong [emphases mine] to begin with. A large body of evidence from many different labs supports the idea that area 25 is “key to successful antidepressant response,” Mayberg says. But “it may be too simple-minded” to think that zapping a single brain node and its connections can effectively treat a disease as complex as depression, Krakauer [John Krakauer, a neuroscientist at Johns Hopkins University in Baltimore, Maryland] says. Figuring that out will likely require more preclinical research in people—a daunting prospect that raises additional ethical dilemmas, Krakauer says. “The hardest thing about being a clinical researcher,” he says, “is knowing when to jump.”
Brain-computer interfaces, symbiosis, and ethical issues
This was the most recent and most directly applicable work that I could find. From a July 24, 2019 article by Liam Drew for Nature Outlook: The brain,
“It becomes part of you,” Patient 6 said, describing the technology that enabled her, after 45 years of severe epilepsy, to halt her disabling seizures. Electrodes had been implanted on the surface of her brain that would send a signal to a hand-held device when they detected signs of impending epileptic activity. On hearing a warning from the device, Patient 6 knew to take a dose of medication to halt the coming seizure.
“You grow gradually into it and get used to it, so it then becomes a part of every day,” she told Frederic Gilbert, an ethicist who studies brain–computer interfaces (BCIs) at the University of Tasmania in Hobart, Australia. “It became me,” she said. [emphasis mine]
Gilbert was interviewing six people who had participated in the first clinical trial of a predictive BCI to help understand how living with a computer that monitors brain activity directly affects individuals psychologically1. Patient 6’s experience was extreme: Gilbert describes her relationship with her BCI as a “radical symbiosis”.
Symbiosis is a term, borrowed from ecology, that means an intimate co-existence of two species for mutual advantage. As technologists work towards directly connecting the human brain to computers, it is increasingly being used to describe humans’ potential relationship with artificial intelligence.
Interface technologies are divided into those that ‘read’ the brain to record brain activity and decode its meaning, and those that ‘write’ to the brain to manipulate activity in specific regions and affect their function.
Commercial research is opaque, but scientists at social-media platform Facebook are known to be pursuing brain-reading techniques for use in headsets that would convert users’ brain activity into text. And neurotechnology companies such as Kernel in Los Angeles, California, and Neuralink, founded by Elon Musk in San Francisco, California, predict bidirectional coupling in which computers respond to people’s brain activity and insert information into their neural circuitry. [emphasis mine]
Already, it is clear that melding digital technologies with human brains can have provocative effects, not least on people’s agency — their ability to act freely and according to their own choices. Although neuroethicists’ priority is to optimize medical practice, their observations also shape the debate about the development of commercial neurotechnologies.
Neuroethicists began to note the complex nature of the therapy’s side effects. “Some effects that might be described as personality changes are more problematic than others,” says Maslen [Hannah Maslen, a neuroethicist at the University of Oxford, UK]. A crucial question is whether the person who is undergoing stimulation can reflect on how they have changed. Gilbert, for instance, describes a DBS patient who started to gamble compulsively, blowing his family’s savings and seeming not to care. He could only understand how problematic his behaviour was when the stimulation was turned off.
Such cases present serious questions about how the technology might affect a person’s ability to give consent to be treated, or for treatment to continue. [emphases mine] If the person who is undergoing DBS is happy to continue, should a concerned family member or doctor be able to overrule them? If someone other than the patient can terminate treatment against the patient’s wishes, it implies that the technology degrades people’s ability to make decisions for themselves. It suggests that if a person thinks in a certain way only when an electrical current alters their brain activity, then those thoughts do not reflect an authentic self.
To observe a person with tetraplegia bringing a drink to their mouth using a BCI-controlled robotic arm is spectacular. [emphasis mine] This rapidly advancing technology works by implanting an array of electrodes either on or in a person’s motor cortex — a brain region involved in planning and executing movements. The activity of the brain is recorded while the individual engages in cognitive tasks, such as imagining that they are moving their hand, and these recordings are used to command the robotic limb.
If neuroscientists could unambiguously discern a person’s intentions from the chattering electrical activity that they record in the brain, and then see that it matched the robotic arm’s actions, ethical concerns would be minimized. But this is not the case. The neural correlates of psychological phenomena are inexact and poorly understood, which means that signals from the brain are increasingly being processed by artificial intelligence (AI) software before reaching prostheses.[emphasis mine]
But, he [Philipp Kellmeyer, a neurologist and neuroethicist at the University of Freiburg, Germany] says, using AI tools also introduces ethical issues of which regulators have little experience. [emphasis mine] Machine-learning software learns to analyse data by generating algorithms that cannot be predicted and that are difficult, or impossible, to comprehend. This introduces an unknown and perhaps unaccountable process between a person’s thoughts and the technology that is acting on their behalf.
Maslen is already helping to shape BCI-device regulation. She is in discussion with the European Commission about regulations it will implement in 2020 that cover non-invasive brain-modulating devices that are sold straight to consumers. [emphases mine; Note: There is a Canadian company selling this type of product, MUSE] Maslen became interested in the safety of these devices, which were covered by only cursory safety regulations. Although such devices are simple, they pass electrical currents through people’s scalps to modulate brain activity. Maslen found reports of them causing burns, headaches and visual disturbances. She also says clinical studies have shown that, although non-invasive electrical stimulation of the brain can enhance certain cognitive abilities, this can come at the cost of deficits in other aspects of cognition.
Regarding my note about MUSE, the company is InteraXon and its product is MUSE.They advertise the product as “Brain Sensing Headbands That Improve Your Meditation Practice.” The company website and the product seem to be one entity, Choose Muse. The company’s product has been used in some serious research papers they can be found here. I did not see any research papers concerning safety issues.
It’s easy to forget that in all the excitement over technologies ‘making our lives better’ that there can be a dark side or two. Some of the points brought forth in the articles by Wolbring, Underwood, and Drew confirmed my uneasiness as reasonable and gave me some specific examples of how these technologies raise new issues or old issues in new ways.
What I find interesting is that no one is using the term ‘cyborg’, which would seem quite applicable.There is an April 20, 2012 posting here titled ‘My mother is a cyborg‘ where I noted that by at lease one definition people with joint replacements, pacemakers, etc. are considered cyborgs. In short, cyborgs or technology integrated into bodies have been amongst us for quite some time.
Interestingly, no one seems to care much when insects are turned into cyborgs (can’t remember who pointed this out) but it is a popular area of research especially for military applications and search and rescue applications.
I’ve sometimes used the term ‘machine/flesh’ and or ‘augmentation’ as a description of technologies integrated with bodies, human or otherwise. You can find lots on the topic here however I’ve tagged or categorized it.
Amongst other pieces you can find here, there’s the August 8, 2016 posting, ‘Technology, athletics, and the ‘new’ human‘ featuring Oscar Pistorius when he was still best known as the ‘blade runner’ and a remarkably successful paralympic athlete. It’s about his efforts to compete against able-bodied athletes at the London Olympic Games in 2012. It is fascinating to read about technology and elite athletes of any kind as they are often the first to try out ‘enhancements’.
Gregor Wolbring has a number of essays on The Conversation looking at Paralympic athletes and their pursuit of enhancements and how all of this is affecting our notions of abilities and disabilities. By extension, one has to assume that ‘abled’ athletes are also affected with the trickle-down effect on the rest of us.
Regardless of where we start the investigation, there is a sameness to the participants in neuroethics discussions with a few experts and commercial interests deciding on how the rest of us (however you define ‘us’ as per Gregor Wolbring’s essay) will live.
This paucity of perspectives is something I was getting at in my COVID-19 editorial for the Canadian Science Policy Centre. My thesis being that we need a range of ideas and insights that cannot be culled from small groups of people who’ve trained and read the same materials or entrepreneurs who too often seem to put profit over thoughtful implementations of new technologies. (See the PDF May 2020 edition [you’ll find me under Policy Development]) or see my May 15, 2020 posting here (with all the sources listed.)
As for this new research at Stanford, it’s exciting news, which raises questions, as it offers the hope of independent movement for people diagnosed as tetraplegic (sometimes known as quadriplegic.)
According to researchers at Helmholtz-Zentrum Dresden-Rossendorf and the rest of the international team collaborating on the work, it’s time to look more closely at plasticity in the neuronal membrane,.
From the abstract for their paper, Intrinsic plasticity of silicon nanowire neurotransistors for dynamic memory and learning functions by Eunhye Baek, Nikhil Ranjan Das, Carlo Vittorio Cannistraci, Taiuk Rim, Gilbert Santiago Cañón Bermúdez, Khrystyna Nych, Hyeonsu Cho, Kihyun Kim, Chang-Ki Baek, Denys Makarov, Ronald Tetzlaff, Leon Chua, Larysa Baraban & Gianaurelio Cuniberti. Nature Electronics volume 3, pages 398–408 (2020) DOI: https://doi.org/10.1038/s41928-020-0412-1 Published online: 25 May 2020 Issue Date: July 2020
Neuromorphic architectures merge learning and memory functions within a single unit cell and in a neuron-like fashion. Research in the field has been mainly focused on the plasticity of artificial synapses. However, the intrinsic plasticity of the neuronal membrane is also important in the implementation of neuromorphic information processing. Here we report a neurotransistor made from a silicon nanowire transistor coated by an ion-doped sol–gel silicate film that can emulate the intrinsic plasticity of the neuronal membrane.
Especially activities in the field of artificial intelligence, like teaching robots to walk or precise automatic image recognition, demand ever more powerful, yet at the same time more economical computer chips. While the optimization of conventional microelectronics is slowly reaching its physical limits, nature offers us a blueprint how information can be processed and stored quickly and efficiently: our own brain.
For the very first time, scientists at TU Dresden and the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) have now successfully imitated the functioning of brain neurons using semiconductor materials. They have published their research results in the journal Nature Electronics (“Intrinsic plasticity of silicon nanowire neurotransistors for dynamic memory and learning functions”).
Today, enhancing the performance of microelectronics is usually achieved by reducing component size, especially of the individual transistors on the silicon computer chips. “But that can’t go on indefinitely – we need new approaches”, Larysa Baraban asserts. The physicist, who has been working at HZDR since the beginning of the year, is one of the three primary authors of the international study, which involved a total of six institutes. One approach is based on the brain, combining data processing with data storage in an artificial neuron.
“Our group has extensive experience with biological and chemical electronic sensors,” Baraban continues. “So, we simulated the properties of neurons using the principles of biosensors and modified a classical field-effect transistor to create an artificial neurotransistor.” The advantage of such an architecture lies in the simultaneous storage and processing of information in a single component. In conventional transistor technology, they are separated, which slows processing time and hence ultimately also limits performance.
Silicon wafer + polymer = chip capable of learning
Modeling computers on the human brain is no new idea. Scientists made attempts to hook up nerve cells to electronics in Petri dishes decades ago. “But a wet computer chip that has to be fed all the time is of no use to anybody,” says Gianaurelio Cuniberti from TU Dresden. The Professor for Materials Science and Nanotechnology is one of the three brains behind the neurotransistor alongside Ronald Tetzlaff, Professor of Fundamentals of Electrical Engineering in Dresden, and Leon Chua [emphasis mine] from the University of California at Berkeley, who had already postulated similar components in the early 1970s.
Now, Cuniberti, Baraban and their team have been able to implement it: “We apply a viscous substance – called solgel – to a conventional silicon wafer with circuits. This polymer hardens and becomes a porous ceramic,” the materials science professor explains. “Ions move between the holes. They are heavier than electrons and slower to return to their position after excitation. This delay, called hysteresis, is what causes the storage effect.” As Cuniberti explains, this is a decisive factor in the functioning of the transistor. “The more an individual transistor is excited, the sooner it will open and let the current flow. This strengthens the connection. The system is learning.”
Cuniberti and his team are not focused on conventional issues, though. “Computers based on our chip would be less precise and tend to estimate mathematical computations rather than calculating them down to the last decimal,” the scientist explains. “But they would be more intelligent. For example, a robot with such processors would learn to walk or grasp; it would possess an optical system and learn to recognize connections. And all this without having to develop any software.” But these are not the only advantages of neuromorphic computers. Thanks to their plasticity, which is similar to that of the human brain, they can adapt to changing tasks during operation and, thus, solve problems for which they were not originally programmed.
I highlighted Dr. Leon Chua’s name as he was one of the first to conceptualize the notion of a memristor (memory resistor), which is what the press release seems to be referencing with the mention of artificial synapses. Dr. Chua very kindly answered a few questions for me about his work which I published in an April 13, 2010 posting (scroll down about 40% of the way).
‘Metal-breathing’ bacteria, eh? A July 28, 2020 news item on Nanowerk announces the research into new materials for electronics (Note: A link has been removed),
When the Shewanella oneidensis bacterium “breathes” in certain metal and sulfur compounds anaerobically, the way an aerobic organism would process oxygen, it produces materials that could be used to enhance electronics, electrochemical energy storage, and drug-delivery devices.
The ability of this bacterium to produce molybdenum disulfide – a material that is able to transfer electrons easily, like graphene – is the focus of research published in Biointerphases (“Synthesis and characterization of molybdenum disulfide nanoparticles in Shewanella oneidensis MR-1 biofilms”) by a team of engineers from Rensselaer Polytechnic Institute.
“This has some serious potential if we can understand this process and control aspects of how the bacteria are making these and other materials,” said Shayla Sawyer, an associate professor of electrical, computer, and systems engineering at Rensselaer.
The research was led by James Rees, who is currently a postdoctoral research associate under the Sawyer group in close partnership and with the support of the Jefferson Project at Lake George — a collaboration between Rensselaer, IBM Research, and The FUND for Lake George that is pioneering a new model for environmental monitoring and prediction. This research is an important step toward developing a new generation of nutrient sensors that can be deployed on lakes and other water bodies.
“We find bacteria that are adapted to specific geochemical or biochemical environments can create, in some cases, very interesting and novel materials,” Rees said. “We are trying to bring that into the electrical engineering world.”
Rees conducted this pioneering work as a graduate student, co-advised by Sawyer and Yuri Gorby, the third author on this paper. Compared with other anaerobic bacteria, one thing that makes Shewanella oneidensis particularly unusual and interesting is that it produces nanowires capable of transferring electrons [emphasis mine].
“That lends itself to connecting to electronic devices that have already been made,” Sawyer said. “So, it’s the interface between the living world and the manmade world that is fascinating.”
Sawyer and Rees also found that, because their electronic signatures can be mapped and monitored, bacterial biofilms could also act as an effective nutrient sensor that could provide Jefferson Project researchers with key information about the health of an aquatic ecosystem like Lake George.
“This groundbreaking work using bacterial biofilms represents the potential for an exciting new generation of ‘living sensors,’ which would completely transform our ability to detect excess nutrients in water bodies in real-time. This is critical to understanding and mitigating harmful algal blooms and other important water quality issues around the world,” said Rick Relyea, director of the Jefferson Project.
Sawyer and Rees plan to continue exploring how to optimally develop this bacterium to harness its wide-ranging potential applications.
“We sometimes get the question with the research: Why bacteria? Or, why bring microbiology into materials science?” Rees said. “Biology has had such a long run of inventing materials through trial and error. The composites and novel structures invented by human scientists are almost a drop in the bucket compared to what biology has been able to do.”
This world-class symposium, the sixth event of its kind, will bring together a record number (1000+) of renowned Canadian and international experts from across the nanomedicines field to:
highlight the discoveries and innovations in nanomedicines that are contributing to global progress in acute, chronic and orphan disease treatment and management;
present up-to-date diagnostic and therapeutic nanomedicine approaches to addressing the challenges of COVID-19; and
facilitate discussion among nanomedicine researchers and innovators and UBC and NMIN clinician-scientists, basic researchers, trainees, and research partners.
Since 2014, Vancouver Nanomedicine Day has advanced nanomedicine research, knowledge mobilization and commercialization in Canada by sharing high-impact findings and facilitating interaction—among researchers, postdoctoral fellows, graduate students, and life science and startup biotechnology companies—to catalyze research collaboration.
I have a few observations, First, Robert Langer is a big deal. Here are a few highlights from his Wikipedia entry (Note: Links have been removed),
Robert Samuel Langer, Jr. FREng (born August 29, 1948) is an American chemical engineer, scientist, entrepreneur, inventor and one of the twelve Institute Professors at the Massachusetts Institute of Technology.
Langer holds over 1,350 granted or pending patents. He is one of the world’s most highly cited researchers, having authored nearly 1,500 scientific papers, and has participated in the founding of multiple technology companies.
Langer is the youngest person in history (at 43) to be elected to all three American science academies: the National Academy of Sciences, the National Academy of Engineering and the Institute of Medicine. He was also elected as a charter member of National Academy of Inventors. He was elected as an International Fellow of the Royal Academy of Engineering in 2010.
It’s all about commercializing the research—or is it?
(This second observation is a little more complicated and requires a little context.) The NMIN is one of Canada’s Networks of Centres of Excellence (who thought that name up? …sigh), from the NMIN About page,
The NCEs seem to be firmly fixed on finding pathways to commercialization (from the NCE About page) Note: All is not as it seems,
Canada’s global economic competitiveness [emphasis mine] depends on making new discoveries and transforming them into products, services [emphasis mine] and processes that improve the lives of Canadians. To meet this challenge, the Networks of Centres of Excellence (NCE) offers a suite of programs that mobilize Canada’s best research, development and entrepreneurial [emphasis mine] expertise and focus it on specific issues and strategic areas.
NCE programs meet Canada’s needs to focus a critical mass of research resources on social and economic challenges, commercialize [emphasis mine] and apply more of its homegrown research breakthroughs, increase private-sector R&D, [emphasis mine] and train highly qualified people. As economic [emphasis mine] and social needs change, programs have evolved to address new challenges.
The fund will invest $275 million over the next 5 years beginning in fiscal 2018-19, and $65 million ongoing, to fund international, interdisciplinary, fast-breaking and high-risk research.
NFRF is composed of three streams to support groundbreaking research.
Exploration generates opportunities for Canada to build strength in high-risk, high-reward and interdisciplinary research;
Transformation provides large-scale support for Canada to build strength and leadership in interdisciplinary and transformative research; and
International enhances opportunities for Canadian researchers to participate in research with international partners.
As you can see there’s no reference to commercialization or economic challenges.
Here at last is the second observation, I find it hard to believe that the government of Canada has given up on the idea of commercializing research and increasing the country’s economic competitiveness through research. Certainly, Langer’s virtual appearance at Vancouver Nanomedicine Day 2020, suggests that at least some corners of the Canadian research establishment are remaining staunchly entrepreneurial.
Canada remains strong in research output and impact, capacity for R&D and innovation at risk: New expert panel report
While Canada is a highly innovative country, with a robust research base and thriving communities of technology start-ups, significant barriers—such as a lack of managerial skills, the experience needed to scale-up companies, and foreign acquisition of high-tech firms—often prevent the translation of innovation into wealth creation.[emphasis mine] The result is a deficit of technology companies growing to scale in Canada, and a loss of associated economic and social benefits.This risks establishing a vicious cycle, where successful companies seek growth opportunities elsewhere due to a lack of critical skills and experience in Canada guiding companies through periods of rapid expansion.
According to the CCA’s [2018 report] Summary webpage, it was Innovation, Science and Economic Development Canada which requested the report. (I wrote up a two-part commentary under one of my favourite titles: “The Hedy Lamarr of international research: Canada’s Third assessment of The State of Science and Technology and Industrial Research and Development in Canada.” Part 1 and Part 2)
I will be fascinated to watch the NFRF and science commercialization situations as they develop.
It seems water can play an important role when using nanocatalysts made of gold nanoparticles combined with metal oxides. From a July 27, 2020 news item on ScienceDaily,
Nanocatalysts made of gold nanoparticles dispersed on metal oxides are very promising for the industrial, selective oxidation of compounds, including alcohols, into valuable chemicals. They show high catalytic activity, particularly in aqueous solution. A team of researchers from Ruhr-Universität Bochum (RUB) has been able to explain why: Water molecules play an active role in facilitating the oxygen dissociation needed for the oxidation reaction. The team of Professor Dominik Marx, Chair of Theoretical Chemistry, reports in the high-impact journal ACS Catalysis on 14 July 2020.
Most industrial oxidation processes involve the use of agents, such as chlorine or organic peroxides, that produce toxic or useless by-products. Instead, using molecular oxygen, O2, and splitting it to obtain the oxygen atoms needed to produce specific products would be a greener and more attractive solution. A promising medium for this approach is the gold/metal oxide (Au/TiO2) system, where the metal oxide titania (TiO2) supports nanoparticles of gold. These nanocatalysts can catalyse the selective oxidation of molecular hydrogen, carbon monoxide and especially alcohols, among others. A crucial step behind all reactions is the dissociation of O2, which comprises a usually high energy barrier. And a crucial unknown in the process is the role of water, since the reactions take place in aqueous solutions.
In a 2018 study, the RUB group of Dominik Marx, Chair of Theoretical Chemistry and Research Area coordinator in the Cluster of Excellence Ruhr Explores Solvation (Resolv), already hinted that water molecules actively participate in the oxidative reaction: They enable a stepwise charge-transfer process that leads to oxygen dissociation in the aqueous phase. Now, the same team reveals that solvation facilitates the activation of molecular oxygen (O2) at the gold/metal oxide (Au/TiO2) nanocatalyst: In fact, water molecules help to decrease the energy barrier for the O2 dissociation. The researchers quantified that the solvent curbs the energy costs by 25 per cent compared to the gas phase. “For the first time, it has been possible to gain insights into the quantitative impact of water on the critical O2 activation reaction for this nanocatalyst – and we also understood why,” says Dominik Marx.
Mind the water molecules
The RUB researchers applied computer simulations, the so-called ab initio molecular dynamics simulations, which explicitly included not only the catalyst but also as many as 80 surrounding water molecules. This was key to gain deep insights into the liquid-phase scenario, which contains water, in direct comparison to the gas phase conditions, where water is absent. “Previous computational work employed significant simplifications or approximations that didn’t account for the true complexity of such a difficult solvent, water,” adds Dr. Niklas Siemer who recently earned his PhD at RUB based on this research.
Scientists simulated the experimental conditions with high temperature and pressure to obtain the free energy profile of O2 in both liquid and gas phase. Finally, they could trace back the mechanistic reason for the solvation effect: Water molecules induce an increase of local electron charge towards oxygen that is anchored at the nanocatalyst perimeter; this in turn leads to the less energetic costs for the dissociation. In the end, say the researchers, it’s all about the unique properties of water: “We found that the polarizability of water and its ability to donate hydrogen bonds are behind oxygen activation,” says Dr. Munoz-Santiburcio. According to the authors, the new computational strategy will help to understand and improve direct oxidation catalysis in water and alcohols.