University of Alberta scientists use ultra fast (terahertz) microscopy to see ultra small (electron dynamics)

This is exciting news for Canadian science and the second time there has been a breakthrough development from the province of Alberta within the last five months (see Sept. 21, 2016 posting on quantum teleportation). From a Feb. 21, 2017 news item on ScienceDaily,

For the first time ever, scientists have captured images of terahertz electron dynamics of a semiconductor surface on the atomic scale. The successful experiment indicates a bright future for the new and quickly growing sub-field called terahertz scanning tunneling microscopy (THz-STM), pioneered by the University of Alberta in Canada. THz-STM allows researchers to image electron behaviour at extremely fast timescales and explore how that behaviour changes between different atoms.

From a Feb. 21, 2017 University of Alberta news release on EurekAlert, which originated the news item, expands on the theme,

“We can essentially zoom in to observe very fast processes with atomic precision and over super fast time scales,” says Vedran Jelic, PhD student at the University of Alberta and lead author on the new study. “THz-STM provides us with a new window into the nanoworld, allowing us to explore ultrafast processes on the atomic scale. We’re talking a picosecond, or a millionth millionth of a second. It’s something that’s never been done before.”

Jelic and his collaborators used their scanning tunneling microscope (STM) to capture images of silicon atoms by raster scanning a very sharp tip across the surface and recording the tip height as it follows the atomic corrugations of the surface. While the original STM can measure and manipulate single atoms–for which its creators earned a Nobel Prize in 1986–it does so using wired electronics and is ultimately limited in speed and thus time resolution.

Modern lasers produce very short light pulses that can measure a whole range of ultra-fast processes, but typically over length scales limited by the wavelength of light at hundreds of nanometers. Much effort has been expended to overcome the challenges of combining ultra-fast lasers with ultra-small microscopy. The University of Alberta scientists addressed these challenges by working in a unique terahertz frequency range of the electromagnetic spectrum that allows wireless implementation. Normally the STM needs an applied voltage in order to operate, but Jelic and his collaborators are able to drive their microscope using pulses of light instead. These pulses occur over really fast timescales, which means the microscope is able to see really fast events.

By incorporating the THz-STM into an ultrahigh vacuum chamber, free from any external contamination or vibration, they are able to accurately position their tip and maintain a perfectly clean surface while imaging ultrafast dynamics of atoms on surfaces. Their next step is to collaborate with fellow material scientists and image a variety of new surfaces on the nanoscale that may one day revolutionize the speed and efficiency of current technology, ranging from solar cells to computer processing.

“Terahertz scanning tunneling microscopy is opening the door to an unexplored regime in physics,” concludes Jelic, who is studying in the Ultrafast Nanotools Lab with University of Alberta professor Frank Hegmann, a world expert in ultra-fast terahertz science and nanophysics.

Here’s are links to and citations for the team’s 2013 paper and their latest,

An ultrafast terahertz scanning tunnelling microscope by Tyler L. Cocker, Vedran Jelic, Manisha Gupta, Sean J. Molesky, Jacob A. J. Burgess, Glenda De Los Reyes, Lyubov V. Titova, Ying Y. Tsui, Mark R. Freeman, & Frank A. Hegmann. Nature Photonics 7, 620–625 (2013) doi:10.1038/nphoton.2013.151 Published online 07 July 2013

Ultrafast terahertz control of extreme tunnel currents through single atoms on a silicon surface by Vedran Jelic, Krzysztof Iwaszczuk, Peter H. Nguyen, Christopher Rathje, Graham J. Hornig, Haille M. Sharum, James R. Hoffman, Mark R. Freeman, & Frank A. Hegmann. Nature Physics (2017)  doi:10.1038/nphys4047 Published online 20 February 2017

Both papers are behind a paywall.

Quantum Shorts & Quantum Applications event at Vancouver’s (Canada) Science World

This is very short notice but if you do have some free time on Thursday, Feb. 23, 2017 from 6 – 8:30 pm, you can check out Science World’s Quantum: The Exhibition for free and watch a series of short films. Here’s more from the Quantum Shorts & Quantum Applications event page,

Join us for an evening of quantum art and science. Visit Quantum: The Exhibition and view a series of short films inspired by the science, history, and philosophy of quantum. Find some answers to your Quantum questions at this mind-expanding panel discussion.

Thursday, February 23: 

6pm                      Check out Quantum: The Exhibition
7pm                      Quantum Shorts Screening
7:45pm                 Panel Discussion/Presentation
8:30pm                 Q & A

Light refreshments will be available.

There are still spaces as of Weds., Feb. 22, 2017:; you can register for the event here.

This will be of the last chances you’ll have to see Quantum: The Exhibition as the show’s here last day is scheduled for Feb. 26, 2017.

Nominations open for Kabiller Prizes in Nanoscience and Nanomedicine ($250,000 for visionary researcher and $10,000 for young investigator)

For a change I can publish something that doesn’t have a deadline in three days or less! Without more ado (from a Feb. 20, 2017 Northwestern University news release by Megan Fellman [h/t Nanowerk’s Feb. 20, 2017 news item]),

Northwestern University’s International Institute for Nanotechnology (IIN) is now accepting nominations for two prestigious international prizes: the $250,000 Kabiller Prize in Nanoscience and Nanomedicine and the $10,000 Kabiller Young Investigator Award in Nanoscience and Nanomedicine.

The deadline for nominations is May 15, 2017. Details are available on the IIN website.

“Our goal is to recognize the outstanding accomplishments in nanoscience and nanomedicine that have the potential to benefit all humankind,” said David G. Kabiller, a Northwestern trustee and alumnus. He is a co-founder of AQR Capital Management, a global investment management firm in Greenwich, Connecticut.

The two prizes, awarded every other year, were established in 2015 through a generous gift from Kabiller. Current Northwestern-affiliated researchers are not eligible for nomination until 2018 for the 2019 prizes.

The Kabiller Prize — the largest monetary award in the world for outstanding achievement in the field of nanomedicine — celebrates researchers who have made the most significant contributions to the field of nanotechnology and its application to medicine and biology.

The Kabiller Young Investigator Award recognizes young emerging researchers who have made recent groundbreaking discoveries with the potential to make a lasting impact in nanoscience and nanomedicine.

“The IIN at Northwestern University is a hub of excellence in the field of nanotechnology,” said Kabiller, chair of the IIN executive council and a graduate of Northwestern’s Weinberg College of Arts and Sciences and Kellogg School of Management. “As such, it is the ideal organization from which to launch these awards recognizing outstanding achievements that have the potential to substantially benefit society.”

Nanoparticles for medical use are typically no larger than 100 nanometers — comparable in size to the molecules in the body. At this scale, the essential properties (e.g., color, melting point, conductivity, etc.) of structures behave uniquely. Researchers are capitalizing on these unique properties in their quest to realize life-changing advances in the diagnosis, treatment and prevention of disease.

“Nanotechnology is one of the key areas of distinction at Northwestern,” said Chad A. Mirkin, IIN director and George B. Rathmann Professor of Chemistry in Weinberg. “We are very grateful for David’s ongoing support and are honored to be stewards of these prestigious awards.”

An international committee of experts in the field will select the winners of the 2017 Kabiller Prize and the 2017 Kabiller Young Investigator Award and announce them in September.

The recipients will be honored at an awards banquet Sept. 27 in Chicago. They also will be recognized at the 2017 IIN Symposium, which will include talks from prestigious speakers, including 2016 Nobel Laureate in Chemistry Ben Feringa, from the University of Groningen, the Netherlands.

2015 recipient of the Kabiller Prize

The winner of the inaugural Kabiller Prize, in 2015, was Joseph DeSimone the Chancellor’s Eminent Professor of Chemistry at the University of North Carolina at Chapel Hill and the William R. Kenan Jr. Distinguished Professor of Chemical Engineering at North Carolina State University and of Chemistry at UNC-Chapel Hill.

DeSimone was honored for his invention of particle replication in non-wetting templates (PRINT) technology that enables the fabrication of precisely defined, shape-specific nanoparticles for advances in disease treatment and prevention. Nanoparticles made with PRINT technology are being used to develop new cancer treatments, inhalable therapeutics for treating pulmonary diseases, such as cystic fibrosis and asthma, and next-generation vaccines for malaria, pneumonia and dengue.

2015 recipient of the Kabiller Young Investigator Award

Warren Chan, professor at the Institute of Biomaterials and Biomedical Engineering at the University of Toronto, was the recipient of the inaugural Kabiller Young Investigator Award, also in 2015. Chan and his research group have developed an infectious disease diagnostic device for a point-of-care use that can differentiate symptoms.

BTW, Warren Chan, winner of the ‘Young Investigator Award’, and/or his work have been featured here a few times, most recently in a Nov. 1, 2016 posting, which is mostly about another award he won but also includes links to some his work including my April 27, 2016 post about the discovery that fewer than 1% of nanoparticle-based drugs reach their destination.

Aliens wreak havoc on our personal electronics

The aliens in question are subatomic particles and the havoc they wreak is low-grade according to the scientist who was presenting on the topic at the AAAS (American Association for the Advancement of Science) 2017 Annual Meeting (Feb. 16 – 20, 2017) in Boston, Massachusetts. From a Feb. 17, 2017 news item on ScienceDaily,

You may not realize it but alien subatomic particles raining down from outer space are wreaking low-grade havoc on your smartphones, computers and other personal electronic devices.

When your computer crashes and you get the dreaded blue screen or your smartphone freezes and you have to go through the time-consuming process of a reset, most likely you blame the manufacturer: Microsoft or Apple or Samsung. In many instances, however, these operational failures may be caused by the impact of electrically charged particles generated by cosmic rays that originate outside the solar system.

“This is a really big problem, but it is mostly invisible to the public,” said Bharat Bhuva, professor of electrical engineering at Vanderbilt University, in a presentation on Friday, Feb. 17 at a session titled “Cloudy with a Chance of Solar Flares: Quantifying the Risk of Space Weather” at the annual meeting of the American Association for the Advancement of Science in Boston.

A Feb. 17, 2017 Vanderbilt University news release (also on EurekAlert), which originated the news item, expands on  the theme,

When cosmic rays traveling at fractions of the speed of light strike the Earth’s atmosphere they create cascades of secondary particles including energetic neutrons, muons, pions and alpha particles. Millions of these particles strike your body each second. Despite their numbers, this subatomic torrent is imperceptible and has no known harmful effects on living organisms. However, a fraction of these particles carry enough energy to interfere with the operation of microelectronic circuitry. When they interact with integrated circuits, they may alter individual bits of data stored in memory. This is called a single-event upset or SEU.

Since it is difficult to know when and where these particles will strike and they do not do any physical damage, the malfunctions they cause are very difficult to characterize. As a result, determining the prevalence of SEUs is not easy or straightforward. “When you have a single bit flip, it could have any number of causes. It could be a software bug or a hardware flaw, for example. The only way you can determine that it is a single-event upset is by eliminating all the other possible causes,” Bhuva explained.

There have been a number of incidents that illustrate how serious the problem can be, Bhuva reported. For example, in 2003 in the town of Schaerbeek, Belgium a bit flip in an electronic voting machine added 4,096 extra votes to one candidate. The error was only detected because it gave the candidate more votes than were possible and it was traced to a single bit flip in the machine’s register. In 2008, the avionics system of a Qantus passenger jet flying from Singapore to Perth appeared to suffer from a single-event upset that caused the autopilot to disengage. As a result, the aircraft dove 690 feet in only 23 seconds, injuring about a third of the passengers seriously enough to cause the aircraft to divert to the nearest airstrip. In addition, there have been a number of unexplained glitches in airline computers – some of which experts feel must have been caused by SEUs – that have resulted in cancellation of hundreds of flights resulting in significant economic losses.

An analysis of SEU failure rates for consumer electronic devices performed by Ritesh Mastipuram and Edwin Wee at Cypress Semiconductor on a previous generation of technology shows how prevalent the problem may be. Their results were published in 2004 in Electronic Design News and provided the following estimates:

  • A simple cell phone with 500 kilobytes of memory should only have one potential error every 28 years.
  • A router farm like those used by Internet providers with only 25 gigabytes of memory may experience one potential networking error that interrupts their operation every 17 hours.
  • A person flying in an airplane at 35,000 feet (where radiation levels are considerably higher than they are at sea level) who is working on a laptop with 500 kilobytes of memory may experience one potential error every five hours.

Bhuva is a member of Vanderbilt’s Radiation Effects Research Group, which was established in 1987 and is the largest academic program in the United States that studies the effects of radiation on electronic systems. The group’s primary focus was on military and space applications. Since 2001, the group has also been analyzing radiation effects on consumer electronics in the terrestrial environment. They have studied this phenomenon in the last eight generations of computer chip technology, including the current generation that uses 3D transistors (known as FinFET) that are only 16 nanometers in size. The 16-nanometer study was funded by a group of top microelectronics companies, including Altera, ARM, AMD, Broadcom, Cisco Systems, Marvell, MediaTek, Renesas, Qualcomm, Synopsys, and TSMC

“The semiconductor manufacturers are very concerned about this problem because it is getting more serious as the size of the transistors in computer chips shrink and the power and capacity of our digital systems increase,” Bhuva said. “In addition, microelectronic circuits are everywhere and our society is becoming increasingly dependent on them.”

To determine the rate of SEUs in 16-nanometer chips, the Vanderbilt researchers took samples of the integrated circuits to the Irradiation of Chips and Electronics (ICE) House at Los Alamos National Laboratory. There they exposed them to a neutron beam and analyzed how many SEUs the chips experienced. Experts measure the failure rate of microelectronic circuits in a unit called a FIT, which stands for failure in time. One FIT is one failure per transistor in one billion hours of operation. That may seem infinitesimal but it adds up extremely quickly with billions of transistors in many of our devices and billions of electronic systems in use today (the number of smartphones alone is in the billions). Most electronic components have failure rates measured in 100’s and 1,000’s of FITs.


Trends in single event upset failure rates at the individual transistor, integrated circuit and system or device level for the three most recent manufacturing technologies. (Bharat Bhuva, Radiation Effects Research Group, Vanderbilt University)

“Our study confirms that this is a serious and growing problem,” said Bhuva.“This did not come as a surprise. Through our research on radiation effects on electronic circuits developed for military and space applications, we have been anticipating such effects on electronic systems operating in the terrestrial environment.”

Although the details of the Vanderbilt studies are proprietary, Bhuva described the general trend that they have found in the last three generations of integrated circuit technology: 28-nanometer, 20-nanometer and 16-nanometer.

As transistor sizes have shrunk, they have required less and less electrical charge to represent a logical bit. So the likelihood that one bit will “flip” from 0 to 1 (or 1 to 0) when struck by an energetic particle has been increasing. This has been partially offset by the fact that as the transistors have gotten smaller they have become smaller targets so the rate at which they are struck has decreased.

More significantly, the current generation of 16-nanometer circuits have a 3D architecture that replaced the previous 2D architecture and has proven to be significantly less susceptible to SEUs. Although this improvement has been offset by the increase in the number of transistors in each chip, the failure rate at the chip level has also dropped slightly. However, the increase in the total number of transistors being used in new electronic systems has meant that the SEU failure rate at the device level has continued to rise.

Unfortunately, it is not practical to simply shield microelectronics from these energetic particles. For example, it would take more than 10 feet of concrete to keep a circuit from being zapped by energetic neutrons. However, there are ways to design computer chips to dramatically reduce their vulnerability.

For cases where reliability is absolutely critical, you can simply design the processors in triplicate and have them vote. Bhuva pointed out: “The probability that SEUs will occur in two of the circuits at the same time is vanishingly small. So if two circuits produce the same result it should be correct.” This is the approach that NASA used to maximize the reliability of spacecraft computer systems.

The good news, Bhuva said, is that the aviation, medical equipment, IT, transportation, communications, financial and power industries are all aware of the problem and are taking steps to address it. “It is only the consumer electronics sector that has been lagging behind in addressing this problem.”

The engineer’s bottom line: “This is a major problem for industry and engineers, but it isn’t something that members of the general public need to worry much about.”

That’s fascinating and I hope the consumer electronics industry catches up with this ‘alien invasion’ issue. Finally, the ‘bit flips’ made me think of the 1956 movie ‘Invasion of the Body Snatchers‘.

Effective sunscreens from nature

The dream is to find sunscreens that don’t endanger humans or pollute the environment and it seems that Spanish scientists may have taken a step closer to making that dream a reality (from a Jan. 30, 2017 Wiley Publications press release (also on EurekAlert),

The ideal sunscreen should block UVB and UVA radiation while being safe and stable. In the journal Angewandte Chemie, Spanish scientists have introduced a new family of UVA and UVB filters based on natural sunscreen substances found in algae and cyanobacteria. They are highly stable and enhance the effectivity [sic] of commercial sunscreens.

Good news for sunseekers. Commercial [sic] available sunscreen lotions can very effectively protect from dangerous radiation in the ultraviolet [spectrum], but they need to be applied regularly and in high amounts to develop their full potential. One of the most critical issues is the limited stability of the UV filter molecules. Inspired by nature, Diego Sampedro and his colleagues from La Rioja University in Logrono and collaborators from Malaga University and Alcala University, Madrid, Spain, have screened a natural class of UV-protecting [blocking?] molecules for their possible use in skin protection. They adjusted the nature-given motif [sic] to the requirements of chemical synthesis and found that the molecules could indeed boost the sun protection factor of common formulations.

The natural sunscreen molecules are called microsporine-like amino acids (MAAs) and are widespread in the microbial world, most prominently in marine algae and cyanobacteria. MAAs are small molecules derived from amino acids, thermally stable, and they absorb light in the ultraviolet region, protecting the microbial DNA from radiation damage. Thus they are natural sunscreens, which inspired Sampedro and his colleagues to create [a] new class of organic sunscreen compounds.

Theoretical calculations revealed what is chemically needed for a successful design. “We performed a computer calculation of several basic scaffolds [..] to identify the simplest compound that fulfills the requisites for efficient sunscreens”, the authors write. The result of their search was a set of molecules which were readily synthesized, “avoiding the decorating substituents that come from the biosynthetic route.” Thus the small basic molecules can be tuned to give them more favorable properties.

The authors found that the synthesized compounds are characterized by excellent filter capacities in the relevant UV range. In addition they are photostable, much more than, for example, oxybenzene [sic] which is a widely used sunscreen in commercial formulations. They do not react chemically and dissipate radiation as heat (but not to such an extent that the skin temperature would rise as well). And, most importantly, when tested in real formulations, the sun protection factor (SPF) rose by a factor of more than two. Thus they could be promising targets for more stable, more efficient sunscreen lotions. Good news for your next summer vacation.

There’s some unusual phrasing so, I’m guessing that the writer it not accustomed to writing press releases in English. One other comment, it’s oxybenzone that’s often used as an ingredient in commercial sunscreens.

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

Rational Design and Synthesis of Efficient Sunscreens To Boost the Solar Protection Factor by Raúl Losantos, Ignacio Funes-Ardoiz, Dr. José Aguilera, Prof. Enrique Herrera-Ceballos, Dr. Cristina García-Iriepa, Prof. Pedro J. Campos, and Diego Sampedro. Angewandte Chemie International Edition Volume 56, Issue 10, pages 2632–2635, March 1, 2017 DOI: 10.1002/anie.201611627 Version of Record online: 27 JAN 2017

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

This paper is behind a paywall.

I have previously featured work on another natural sunscreen. In that case it was to be derived from English ivy (July 22, 2010 posting); there was an update on the English ivy work in a May 30, 2016 posting but the researcher has moved in a different direction looking at wound healing and armour as possible applications for the research.

Curiosity may not kill the cat but, in science, it might be an antidote to partisanship

I haven’t stumbled across anything from the Cultural Cognition Project at Yale Law School in years so before moving onto their latest news, here’s more about the project,

The Cultural Cognition Project is a group of scholars interested in studying how cultural values shape public risk perceptions and related policy beliefs. Cultural cognition refers to the tendency of individuals to conform their beliefs about disputed matters of fact (e.g., whether global warming is a serious threat; whether the death penalty deters murder; whether gun control makes society more safe or less) to values that define their cultural identities.Project members are using the methods of various disciplines — including social psychology, anthropology, communications, and political science — to chart the impact of this phenomenon and to identify the mechanisms through which it operates. The Project also has an explicit normative objective: to identify processes of democratic decisionmaking by which society can resolve culturally grounded differences in belief in a manner that is both congenial to persons of diverse cultural outlooks and consistent with sound public policymaking.

It’s nice to catch up with some of the project’s latest work, from a Jan. 26, 2017 Yale University news release (also on EurekAlert),

Disputes over science-related policy issues such as climate change or fracking often seem as intractable as other politically charged debates. But in science, at least, simple curiosity might help bridge that partisan divide, according to new research.

In a study slated for publication in the journal Advances in Political Psychology, a Yale-led research team found that people who are curious about science are less polarized in their views on contentious issues than less-curious peers.

In an experiment, they found out why: Science-curious individuals are more willing to engage with surprising information that runs counter to their political predispositions.

“It’s a well-established finding that most people prefer to read or otherwise be exposed to information that fits rather than challenges their political preconceptions,” said research team leader Dan Kahan, Elizabeth K. Dollard Professor of Law and professor of psychology at Yale Law School. “This is called the echo-chamber effect.”

But science-curious individuals are more likely to venture out of that chamber, he said.

“When they are offered the choice to read news articles that support their views or challenge them on the basis of new evidence, science-curious individuals opt for the challenging information,” Kahan said. “For them, surprising pieces of evidence are bright shiny objects — they can’t help but grab at them.”

Kahan and other social scientists previously have shown that information based on scientific evidence can actually intensify — rather than moderate — political polarization on contentious topics such as gun control, climate change, fracking, or the safety of certain vaccines. The new study, which assessed science knowledge among subjects, reiterates the gaping divide separating how conservatives and liberals view science.

Republicans and Democrats with limited knowledge of science were equally likely to agree or disagree with the statement that “there is solid evidence that global warming is caused by human activity. However, the most science-literate conservatives were much more likely to disagree with the statement than less-knowledgeable peers. The most knowledgeable liberals almost universally agreed with the statement.

“Whatever measure of critical reasoning we used, we always observed this depressing pattern: The members of the public most able to make sense of scientific evidence are in fact the most polarized,” Kahan said.

But knowledge of science, and curiosity about science, are not the same thing, the study shows.

The team became interested in curiosity because of its ongoing collaborative research project to improve public engagement with science documentaries involving the Cultural Cognition Project at Yale Law School, the Annenberg Public Policy Center of the University of Pennsylvania, and Tangled Bank Studios at the Howard Hughes Medical Institute.

They noticed that the curious — those who sought out science stories for personal pleasure — not only were more interested in viewing science films on a variety of topics but also did not display political polarization associated with contentious science issues.

The new study found, for instance, that a much higher percentage of curious liberals and conservatives chose to read stories that ran counter to their political beliefs than did their non-curious peers.

“As their science curiosity goes up, the polarizing effects of higher science comprehension dissipate, and people move the same direction on contentious policies like climate change and fracking,” Kahan said.

It is unclear whether curiosity applied to other controversial issues can minimize the partisan rancor that infects other areas of society. But Kahan believes that the curious from both sides of the political and cultural divide should make good ambassadors to the more doctrinaire members of their own groups.

“Politically curious people are a resource who can promote enlightened self-government by sharing scientific information they are naturally inclined to learn and share,” he said.

Here’s my standard link to and citation for the paper,

Science Curiosity and Political Information Processing by Dan M. Kahan, Asheley R Landrum, Katie Carpenter, Laura Helft, and Kathleen Hall Jamieson. Political Psychology Volume 38, Issue Supplement S1 February 2017 Pages 179–199 DOI: 10.1111/pops.12396View First published: 26 January 2017

This paper is open and it can also be accessed here.

I last mentioned Kahan and The Cultural Cognition Project in an April 10, 2014 posting (scroll down about 45% of the way) about responsible science.

Live. Curiously. A Feb. 22, 2017 Curiosity Collider Café event in Vancouver, Canada

There’s news about the next Curiosity Collider Café event in a Feb. 14, 2017 announcement (received via email),

Collider Cafe: Live. Curiously.

8:00pm on Wednesday, February 22nd, 2017. Door opens at 7:30pm.

Café Deux Soleils. 2096 Commercial Drive, Vancouver, BC (Google Map).

$5.00-10.00 cover at the door (sliding scale). Proceeds will be used to cover the cost of running this event, and to fund future Curiosity Collider events. Curiosity Collider is a registered BC non-profit organization.


#ColliderCafe is a space for artists, scientists, makers, and anyone interested in art+science. Meet, discover, connect, create. How do you explore curiosity in your life? Join us and discover how our speakers explore their own curiosity at the intersection of art & science.

The event will start promptly at 8pm (doors open at 7:30pm). $5.00-10.00 (sliding scale) cover at the door. Proceeds will be used to cover the cost of running this event, and to fund future Curiosity Collider events. Curiosity Collider is a registered BC non-profit organization.

Let us know you are coming on our Facebook page!

You can find out more about Curiousity Collider and its events here. Also, they have produced a very pretty poster,

Using sugar for a better way to clean nanoparticles from organisms

Researchers at the US National Institute of Standards and Technology (NIST) have found that a laboratory technique used for over 60 years is the best way to date to clean nanoparticles from organisms. From a Jan. 26, 2017 news item on ScienceDaily,

Sometimes old-school methods provide the best ways of studying cutting-edge tech and its effects on the modern world.

Giving a 65-year-old laboratory technique a new role, researchers at the National Institute of Standards and Technology (NIST) have performed the cleanest separation to date of synthetic nanoparticles from a living organism. The new NIST method is expected to significantly improve experiments looking at the potential environmental and health impacts of these manufactured entities. It will allow scientists to more accurately count how many nanoparticles have actually been ingested by organisms exposed to them.

A Jan. 26, 2017 NIST news release (also on EurekAlert), which originated the news item, offers more detail,

The common roundworm Caenorhabditis elegans has been used in recent years as a living model for laboratory studies of how biological and chemical compounds may affect multicellular organisms. These compounds include engineered nanoparticles (ENPs), bits of material between 1 and 100 nanometers (billionths of a meter, or about 1/10,000 the diameter of a red blood cell). Previous research has often focused on quantifying the amount and size of engineered nanoparticles ingested by C. elegans. Measuring the nanoparticles that actually make it into an organism is considered a more relevant indicator of potential toxicity than just the amount of ENPs to which the worms are exposed.

Traditional methods for counting ingested ENPs have produced questionable results. Currently, researchers expose C. elegans to metal ENPs such as silver or gold in solution, then rinse the excess particles away with water followed by centrifugation and freeze-drying. A portion of the “cleaned” sample produced is then typically examined by a technique that determines the amount of metal present, known as inductively coupled plasma mass spectrometry (ICP-MS). It often yields ENP counts in the tens of thousands per worm; however, those numbers always seem too high to NIST researchers working with C. elegans.

“Since ICP-MS will detect all of the nanoparticles associated with the worms, both those ingested and those that remain attached externally, we suspect that the latter is what makes the ‘ENPs’ per-worm counts so high,” said NIST analytical chemist Monique Johnson (link sends e-mail), the lead author on the ACS Nano paper. “Since we only wanted to quantify the ingested ENPs, a more robust and reliable separation method was needed.”

Luckily, the solution to the problem was already in the lab.

Cross section of the roundworm C. elegans

Scanning electron micrograph showing a cross section of the roundworm C. elegans with two ingested engineered nanoparticles (red dots just right of center). Images such as this provided NIST researchers with visual confirmation that nanoparticle consumption actually occurred. Credit: K. Scott/NIST

In the course of culturing C. elegans for ENP-exposure experiments, Johnson and her colleagues had used sucrose density gradient centrifugation, a decades-old and established system for cleanly separating cellular components, to isolate the worms from debris and bacteria. “We wondered if the same process would allow us to perform an organism-from-ENP separation as well, so I designed a study to find out,” Johnson said.

In their experiment, the NIST researchers first exposed separate samples of C. elegans to low and high concentrations of two sizes of gold nanospheres, 30 and 60 nanometers in diameter. The researchers put each of the samples into a centrifuge and removed the supernatant (liquid portion), leaving the worms and ENPs in the remaining pellets. These were centrifuged twice in a salt solution (rather than just water as in previous separation methods), and then centrifuged again, but this time, through a uniquely designed sucrose density gradient.

“From top to bottom, our gradient consisted of a salt solution layer to trap excess ENPs and three increasingly dense layers of sucrose [20, 40 and 50 percent] to isolate the C. elegans,” Johnson explained. “We followed up the gradient with three water rinses and with centrifugations to ensure that only worms with ingested ENPs, and not the sucrose separation medium with any excess ENPs, would make it into the final pellet.”

Analyzing the range of masses in the ultrapurified samples indicated gold levels more in line with what the researchers expected would be found as ingested ENPs. Experimental validation of the NIST separation method’s success came when the worms were examined in detail under a scanning electron microscope (SEM).

“For me, the eureka moment was when I first saw gold ENPs in the cross section images taken from the C. elegans samples that had been processed through the sucrose density gradient,” Johnson said. “I had been dreaming about finding ENPs in the worm’s digestive tract and now they were really there!”

The high-resolution SEM images also provided visual evidence that only ingested ENPs were counted. “No ENPs were attached to the cuticle, the exoskeleton of C. elegans, in any of the sucrose density gradient samples,” Johnson said. “When we examined worms from our control experiments [processed using the traditional no-gradient, water-rinse-only separation method], there were a number of nanospheres found attached to the cuticle.

Now that it has been successfully demonstrated, the NIST researchers plan to refine and further validate their system for evaluating the uptake of ENPs by C. elegans. “Hopefully, our method will become a useful and valuable tool for reducing the measurement variability and sampling bias that can plague environmental nanotoxicology studies,” Johnson said.

They’ve tested this technique on gold nanoparticles, which begs the question, What kinds of nanoparticles can this technique be used for? Metal nanoparticles only or all nanoparticles?

I’m sure the researchers have already asked these questions and started researching the answers. While the rest of us wait, here’s a link to and a citation for the paper about this promising new technique,

Separation, Sizing, and Quantitation of Engineered Nanoparticles in an Organism Model Using Inductively Coupled Plasma Mass Spectrometry and Image Analysis by Monique E. Johnson, Shannon K. Hanna, Antonio R. Montoro Bustos, Christopher M. Sims, Lindsay C. C. Elliott, Akshay Lingayat, Adrian C. Johnston, Babak Nikoobakht, John T. Elliott, R. David Holbrook, Keana C. K. Scott, Karen E. Murphy, Elijah J. Petersen, Lee L. Yu, and Bryant C. Nelson. ACS Nano, 2017, 11 (1), pp 526–540 DOI: 10.1021/acsnano.6b06582 Publication Date (Web): December 16, 2016

Copyright This article not subject to U.S. Copyright. Published 2016 by the American Chemical Society

This paper is behind a paywall.

Nanoparticle fertilizer and dreams of a new ‘Green’ revolution

There were hints even while it was happening that the ‘Green Revolution’ of the 1960s was not all it was touted to be. (For those who haven’t come across the term before, the Green Revolution was a better way to farm, a way that would feed everyone on earth. Or, that was the dream.)

Perhaps this time, they’ll be more successful. From a Jan. 15, 2017 news item on ScienceDaily, which offers a perspective on the ‘Green Revolution’ that differs from mine,

The “Green Revolution” of the ’60s and ’70s has been credited with helping to feed billions around the world, with fertilizers being one of the key drivers spurring the agricultural boom. But in developing countries, the cost of fertilizer remains relatively high and can limit food production. Now researchers report in the journal ACS Nano a simple way to make a benign, more efficient fertilizer that could contribute to a second food revolution.

A Jan. 25, 2017 American Chemical Society news release on EurekAlert, which originated the news item, expands on the theme,

Farmers often use urea, a rich source of nitrogen, as fertilizer. Its flaw, however, is that it breaks down quickly in wet soil and forms ammonia. The ammonia is washed away, creating a major environmental issue as it leads to eutrophication of water ways and ultimately enters the atmosphere as nitrogen dioxide, the main greenhouse gas associated with agriculture. This fast decomposition also limits the amount of nitrogen that can get absorbed by crop roots and requires farmers to apply more fertilizer to boost production. However, in low-income regions where populations continue to grow and the food supply is unstable, the cost of fertilizer can hinder additional applications and cripple crop yields. Nilwala Kottegoda, Veranja Karunaratne, Gehan Amaratunga and colleagues wanted to find a way to slow the breakdown of urea and make one application of fertilizer last longer.

To do this, the researchers developed a simple and scalable method for coating hydroxyapatite (HA) nanoparticles with urea molecules. HA is a mineral found in human and animal tissues and is considered to be environmentally friendly. In water, the hybridization of the HA nanoparticles and urea slowly released nitrogen, 12 times slower than urea by itself. Initial field tests on rice farms showed that the HA-urea nanohybrid lowered the need for fertilizer by one-half. The researchers say their development could help contribute to a new green revolution to help feed the world’s continuously growing population and also improve the environmental sustainability of agriculture.

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

Urea-Hydroxyapatite Nanohybrids for Slow Release of Nitrogen by Nilwala Kottegoda, Chanaka Sandaruwan, Gayan Priyadarshana, Asitha Siriwardhana, Upendra A. Rathnayake, Danushka Madushanka Berugoda Arachchige, Asurusinghe R. Kumarasinghe, Damayanthi Dahanayake, Veranja Karunaratne, and Gehan A. J. Amaratunga. ACS Nano, Article ASAP DOI: 10.1021/acsnano.6b07781 Publication Date (Web): January 25, 2017

Copyright © 2017 American Chemical Society

This paper is open access.

Imprinting fibres at the nanometric scale

Switzerland’s École Polytechnique Fédérale de Lausanne (EPFL) announces a discovery in a Jan. 24, 2017 press release (also on EurkeAlert),

Researchers at EPFL have come up with a way of imprinting nanometric patterns on the inside and outside of polymer fibers. These fibers could prove useful in guiding nerve regeneration and producing optical effects, for example, as well as in eventually creating artificial tissue and smart bandages.

Researchers at EPFL’s Laboratory of Photonic Materials and Fibre Devices, which is run by Fabien Sorin, have come up with a simple and innovative technique for drawing or imprinting complex, nanometric patterns on hollow polymer fibers. Their work has been published in Advanced Functional Materials.

The potential applications of this breakthrough are numerous. The imprinted designs could be used to impart certain optical effects on a fiber or make it water-resistant. They could also guide stem-cell growth in textured fiber channels or be used to break down the fiber at a specific location and point in time in order to release drugs as part of a smart bandage.

Stretching the fiber like molten plastic

To make their nanometric imprints, the researchers began with a technique called thermal drawing, which is the technique used to fabricate optical fibers. Thermal drawing involves engraving or imprinting millimeter-sized patterns on a preform, which is a macroscopic version of the target fiber. The imprinted preform is heated to change its viscosity, stretched like molten plastic into a long, thin fiber and then allowed to harden again. Stretching causes the pattern to shrink while maintaining its proportions and position. Yet this method has a major shortcoming: the pattern does not remain intact below the micrometer scale. “When the fiber is stretched, the surface tension of the structured polymer causes the pattern to deform and even disappear below a certain size, around several microns,” said Sorin.

To avoid this problem, the EPFL researchers came up with the idea of sandwiching the imprinted preform in a sacrificial polymer [emphasis mine]. This polymer protects the pattern during stretching by reducing the surface tension. It is discarded once the stretching is complete. Thanks to this trick, the researchers are able to apply tiny and highly complex patterns to various types of fibers. “We have achieved 300-nanometer patterns, but we could easily make them as small as several tens of nanometers,” said Sorin. This is the first time that such minute and highly complex patterns have been imprinted on flexible fiber on a very large scale. “This technique enables to achieve textures with feature sizes two order of magnitude smaller than previously reported,” said Sorin. “It could be applied to kilometers of fibers at a highly reasonable cost.”

To highlight potential applications of their achievement, the researchers teamed up with the Bertarelli Foundation Chair in Neuroprosthetic Technology, led by Stéphanie Lacour. Working in vitro, they were able to use their fibers to guide neurites from a spinal ganglion (on the spinal nerve). This was an encouraging step toward using these fibers to help nerves regenerate or to create artificial tissue.

This development could have implications in many other fields besides biology. “Fibers that are rendered water-resistant by the pattern could be used to make clothes. Or we could give the fibers special optical effects for design or detection purposes. There is also much to be done with the many new microfluidic systems out there,” said Sorin. The next step for the researchers will be to join forces with other EPFL labs on initiatives such as studying in vivo nerve regeneration. All this, thanks to the wonder of imprinted polymer fibers.

I like the term “sacrificial polymer.”

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

Controlled Sub-Micrometer Hierarchical Textures Engineered in Polymeric Fibers and Microchannels via Thermal Drawing by Tung Nguyen-Dang, Alba C. de Luca, Wei Yan, Yunpeng Qu, Alexis G. Page, Marco Volpi, Tapajyoti Das Gupta, Stéphanie P. Lacour, and Fabien Sorin. Advanced Functional Materials DOI: 10.1002/adfm.201605935 Version of Record online: 24 JAN 2017

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

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