Monthly Archives: April 2015

Outcomes for US-European Union bridging Nano environment, health, and safety (EHS) research workshop

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According to Lynn Bergeson in an April 14, 2015 news item on Nanotechnology Now, a US-European Union (EU) workshop on nanosafety has published a document,

The National Nanotechnology Initiative (NNI) published on March 23, 2015, the outcomes of the March 12-13, 2015, joint workshop held by the U.S. and the European Union (EU), “Bridging NanoEHS Research Efforts.” …

A US National Nanotechnology Initiative (NNI) ??, ??, 2015 notice on the nano.gov site provides more details,

Workshop participants reviewed progress toward COR [communities of research] goals and objectives, shared best practices, and identified areas for cross-COR collaboration.  To address new challenges the CORs were realigned and expanded with the addition of a COR on nanotechnology characterization. The seven CORs now address:

Characterization
Databases and Computational Modeling
Exposure through Product Life
EcoToxicity
Human Toxicity
Risk Assessment
Risk Management and Control

The CORs support the shared goal of responsible nanotechnology development as outlined in the U.S. National Nanotechnology Initiative EHS Research Strategy, and the research strategy of the EU NanoSafety Cluster. The CORs directly address several priorities described in the documents above, including the creation of a comprehensive nanoEHS knowledge base and international cooperation on the development of best practices and consensus standards.

The CORs are self-run, with technical support provided by the European Commission and the U.S. National Nanotechnology Coordination Office. Each Community has European and American co-chairs who convene meetings and teleconferences, guide the discussions, and set the group’s agenda. Participation in the CORs is free and open to any interested individuals. More information is available at www.us-eu.org.

The workshop was organized by the European Commission and the U.S. National Nanotechnology Initiative under the auspices of the agreement for scientific and technological cooperation between the European Union and the United States.

Coincidentally, I received an April 13, 2015 notice about the European Commission’s NanoSafety Cluster’s Spring 2015 newsletter concerning their efforts but found no mention of the ‘bridging workshop’. Presumably, information was not available prior to the newsletter’s deadline.

In my April 8, 2014 posting about a US proposed rule for reporting nanomaterials, I included information about the US and its efforts to promote or participate in harmonizing the nano situation internationally. Scroll down about 35% of the way to find information about the Canada-U.S. Regulatory Cooperation Council (RCC) Nanotechnology Initiative, the Organisation for Economic Cooperation and Development (OECD) effort, and the International Organization for Standardization (ISO) effort.

Electronic organic micropump for direct drug delivery to the brain

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I can understand the appeal but have some questions about this micropump in the brain concept. First, here’s more about the research from an April 16, 2015 news item on Nanowerk,

Many potentially efficient drugs have been created to treat neurological disorders, but they cannot be used in practice. Typically, for a condition such as epilepsy, it is essential to act at exactly the right time and place in the brain. For this reason, the team of researchers led by Christophe Bernard at Inserm Unit 1106, “Institute of Systems Neuroscience” (INS), with the help of scientists at the École des Mines de Saint-Étienne and Linköping University (Sweden) have developed an organic electronic micropump which, when combined with an anticonvulsant drug, enables localised inhibition of epileptic seizure in brain tissue in vitro.

An April 16, 2015 INSERM (Institut national de la santé et de la recherche médicale) press release on EurekAlert, which originated the news item, goes on to describe the problem the researchers are attempting to solve and their solution to it,

Drugs constitute the most widely used approach for treating brain disorders. However, many promising drugs failed during clinical testing for several reasons:

  • they are diluted in potentially toxic solutions,
  • they may themselves be toxic when they reach organs to which they were not initially directed,
  • the blood-brain barrier, which separates the brain from the blood circulation, prevents most drugs from reaching their targets in the brain,
  • drugs that succeed in penetrating the brain will act in a non-specific manner, i.e. on healthy regions of the brain, altering their functions.

Epilepsy is a typical example of a condition for which many drugs could not be commercialised because of their harmful effects, when they might have been effective for treating patients resistant to conventional treatments [1].

During an epileptic seizure, the nerve cells in a specific area of the brain are suddenly activated in an excessive manner. How can this phenomenon be controlled without affecting healthy brain regions? To answer this question, Christophe Bernard’s team, in collaboration with a team led by George Malliaras at the Georges Charpak-Provence Campus of the École des Mines of Saint-Étienne and Swedish scientists led by Magnus Berggren from Linköping University, have developed a biocompatible micropump that makes it possible to deliver therapeutic substances directly to the relevant areas of the brain.

The micropump (20 times thinner than a hair) is composed of a membrane known as “cation exchange,” i.e., it has negative ions attached to its surface. It thus attracts small positively charged molecules, whether these are ions or drugs. When an electrical current is applied to it, the flow of electrons generated projects the molecules of interest toward the target area.

To enable validation of this new technique, the researchers reproduced the hyperexcitability of epileptic neurons in mouse brains in vitro. They then injected GABA, a compound naturally produced in the brain and that inhibits neurons, into this hyperactive region using the micropump. The scientists then observed that the compound not only stopped this abnormal activity in the target region, but, most importantly, did not interfere with the functioning of the neighbouring regions.

This technology may thus resolve all the above-mentioned problems, by allowing very localised action, directly in the brain and without peripheral toxicity.

“By combining electrodes, such as those used to treat Parkinson’s disease, with this micropump, it may be possible to use this technology to treat patients with epilepsy who are resistant to conventional treatments, and those for whom the side-effects are too great,” explains Christophe Bernard, Inserm Research Director.

Based on these initial results, the researchers are now working to move on to an in vivo animal model and the possibility of combining this high-technology system with the microchip they previously developed in 2013. The device could be embedded and autonomous. The chip would be used to detect the imminent occurrence of a seizure, in order to activate the pump to inject the drug at just the right moment. It may therefore be possible to control brain activity where and when it is needed.

In addition to epilepsy, this state-of-the-art technology, combined with existing drugs, offers new opportunities for many brain diseases that remain difficult to treat at this time.

###

[1] Epilepsy in brief

This disease, which affects nearly 50 million people in the world, is the most common neurological disorder after migraine.

The neuronal dysfunctions associated with epilepsy lead to attacks with variable symptoms, from loss of consciousness to disorders of movement, sensation or mood.

Despite advances in medicine, 30% of those affected are resistant to all treatments.

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

Controlling Epileptiform Activity with Organic Electronic Ion Pumps by Adam Williamson, Jonathan Rivnay, Loïg Kergoat, Amanda Jonsson, Sahika Inal, Ilke Uguz, Marc Ferro, Anton Ivanov, Theresia Arbring-Sjöström, Daniel T. Simon, Magnus Berggren, George G. Malliaras, and Christophe Bernardi. Advanced Materials First published: 11 April 2015Full publication history DOI: 10.1002/adma.201500482

This paper is behind a paywall.

Finally, my questions. How does the pump get refilled once the drugs are used up? Do you get a warning when the drug supply is almost nil? How does that warning work? Does implanting the pump require brain surgery or is there a less intrusive fashion of placing this pump exactly where you want it to be? Once it’s been implanted, how do you find a pump  20 times thinner than a human hair?

For some reason this micropump brought back memories of working in high tech environments where developers would come up with all kinds of nifty ideas but put absolutely no thought into how these ideas might actually work once human human beings got their hands on the product. In any event, the micropump seems exciting and I hope researchers work out the kinks, implementationwise, before they’re implanted.

Graphite research at Simon Fraser University (Vancouver, Canada) and NanoXplore’s (Montréal, Canada) graphene oxide production

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Graphite

Simon Fraser University (SFU) announced a partnership with Ontario’s Sheridan College and three Canadian companies (Terrella Energy Systems, Alpha Technologies, and Westport Innovations) in a research project investigating low-cost graphite thermal management products. From an April 9, 2015 SFU news release,

Simon Fraser University is partnering with Ontario’s Sheridan College, and a trio of Canadian companies, on research aimed at helping the companies to gain market advantage from improvements on low-cost graphite thermal management products.

 

Graphite is an advanced engineering material with key properties that have potential applications in green energy systems, automotive components and heating ventilating air conditioning systems.

 

The project combines expertise from SFU’s Laboratory for Alternative Energy Conversion with Sheridan’s Centre for Advanced Manufacturing and Design Technologies.

 

With $700,000 in funding from the Natural Sciences and Engineering Research Council’s (NSERC) College and Community Innovation program, the research will help accelerate the development and commercialization of this promising technology, says project lead Majid Bahrami, an associate professor in SFU’s School of Mechatronics Systems Engineering (MSE) at SFU’s Surrey campus.

 

The proposed graphite products take aim at a strategic $40 billion/year thermal management products market, Bahrami notes. 

 

Inspired by the needs of the companies, Bahrami says the project has strong potential for generating intellectual property, leading to advanced manufacturing processes as well as new, efficient graphite thermal products.

 

The companies involved include:

 

Terrella Energy Systems, which recently developed a roll-embossing process that allows high-volume, cost-effective manufacturing of micro-patterned, coated and flexible graphite sheets;

 

Alpha Technologies, a leading telecom/electronics manufacturer, which is in the process of developing next-generation ‘green’ cooling solutions for their telecom/electronics systems;

 

Westport Innovations, which is interested in integrating graphite heat exchangers in their natural gas fuel systems, such as heat exchangers for heavy-duty trucks.

 

Bahrami, who holds a Canada Research Chair in Alternative Energy Conversion Systems, expects the project will also lead to significant training and future business and employment opportunities in the manufacturing and energy industry, as well as the natural resource sector and their supply chain.

 

“This project leverages previous federal government investment into world-class testing equipment, and SFU’s strong industrial relationships and entrepreneurial culture, to realize collective benefits for students, researchers, and companies,” says Joy Johnson, SFU’s VP Research. “By working together and pooling resources, SFU and its partners will continue to generate novel green technologies and energy conversion solutions.”

 

Fast Facts:

  • The goal of the NSERC College and Community Innovation program is to increase innovation at the community and/or regional level by enabling Canadian colleges to increase their capacity to work with local companies, particularly small and medium-sized enterprises (SMEs).
  • Canada is the fifth largest exporter of raw graphite.
  • …

I have mentioned graphite here before. Generally, it’s in relation to graphite mining deposits in Ontario and Québec, which seem to have been of great interest as a source for graphene production. A Feb. 20, 2015 posting was the the latest of those mentions and, coincidentally, it features NanoXplore and graphene, the other topic noted in the head for this posting.

Graphene and NanoXplore

An April 17, 2015 news item on Azonano makes a production announcement,

Group NanoXplore Inc., a Montreal-based company specialising in the production and application of graphene and its derivative materials, announced today that it is producing Graphene Oxide in industrial quantities. The Graphene Oxide is being produced in the same 3 metric tonne per year facility used to manufacture NanoXplore’s standard graphene grades and derivative products such as a unique graphite-graphene composite suitable for anodes in Li-ion batteries.

An April 16, 2015 NanoXplore news release on MarketWired, which originated the news item, describes graphene oxide and its various uses,

Graphene Oxide (GO) is similar to graphene but with significant amounts of oxygen introduced into the graphene structure. GO, unlike graphene, can be readily mixed in water which has led people to use GO in thin films, water-based paints and inks, and biomedical applications. GO is relatively simple to synthesise on a lab scale using a modified Hummers’ method, but scale-up to industrial production is quite challenging and dangerous. This is because the Hummers’ method uses strong oxidizing agents in a highly exothermic reaction which produces toxic and explosive gas. NanoXplore has developed a completely new and different approach to producing GO based upon its proprietary graphene production platform. This novel production process is completely safe and environmentally friendly and produces GO in volumes ranging from kilogram to tonne quantities.

“NanoXplore’s ability to produce industrially useful quantities of Graphene Oxide in a safe and scalable manner is a game changer, said Dr. Soroush Nazarpour, President and CEO of NanoXplore. “Mixing graphene with standard industrially materials is the key to bringing it to industrial markets. Graphene Oxide mixes extremely well with all water based solutions, and we have received repeated customer requests for water soluble graphene over the last two years”.

It sounds exciting but it would be helpful (for someone like me, who’s ignorant about these things) to know the graphene oxide market’s size. This would help me to contextualize the excitement.

You can find out more about NanoXplore here.

Please, don’t kill my hive! (a Science Rap Academy production)

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In celebration of an upcoming event in Vancouver (Canada), “Honey, Hives, and Poetry,” I’m including this April 17, 2015 news from David Bruggeman (on his Pasco Phronesis blog),

Tom McFadden has debuted the first video of this year’s Science Rap Academy.  Seventh and eighth grade students at the Nueva School prepare a music video based on a science concept, usually reworking a rap or hip-hop song.

Here’s the first installment in this year’s Science Rap Academy series, Please Don’t Kill My Hive,

There are many posts on this blog about Tom McFadden and his various science rap projects (many of them courtesy of David Bruggeman/Pasco Phronesis). Here’s one of the more recent ones, a May 30, 2014 posting.

Getting back to David’s April 17, 2015 news, he also mentions the latest installment of  “Science goes to the movies” which features three movies (Kingsman: The Secret Service, The Lazarus Effect, and Them!) and has Neil deGrasse Tyson as a guest. David has embedded the episode on his blog. One brief comment, it’s hard to tell how familiar Tyson or the hosts, Faith Salie and Dr. Heather Berlin are with the history of the novel or science. But the first few minutes of the conversation suggest that Mary Shelley’s Frankenstein is the first novel to demonize scientists. (I had the advantage of not getting caught up in their moment and access to search engines.) Well, novels were still pretty new in Europe and I don’t believe that there were any other novels featuring scientists prior to Mary Shelley’s work.

A brief history of novels: Japan can lay claim to the first novel, The Tale of Genji, in the 11th century CE, (The plot concerned itself with aristocratic life and romance.) Europe and its experience with the novel is a little more confusing. From the City University of New York, Brooklyn site, The Novel webpage,

The term for the novel in most European languages is roman, which suggests its closeness to the medieval romance. The English name is derived from the Italian novella, meaning “a little new thing.” Romances and novelle, short tales in prose, were predecessors of the novel, as were picaresque narratives. Picaro is Spanish for “rogue,” and the typical picaresque story is of the escapades of a rascal who lives by his wits. The development of the realistic novel owes much to such works, which were written to deflate romantic or idealized fictional forms. Cervantes’ Don Quixote (1605-15), the story of an engaging madman who tries to live by the ideals of chivalric romance, explores the role of illusion and reality in life and was the single most important progenitor of the modern novel.

The novel broke from those narrative predecessors that used timeless stories to mirror unchanging moral truths. It was a product of an intellectual milieu shaped by the great seventeenth-century philosophers, Descartes and Locke, who insisted upon the importance of individual experience. They believed that reality could be discovered by the individual through the senses. Thus, the novel emphasized specific, observed details. It individualized its characters by locating them precisely in time and space. And its subjects reflected the popular eighteenth-century concern with the social structures of everyday life.

The novel is often said to have emerged with the appearance of Daniel Defoe’s Robinson Crusoe (1719) and Moll Flanders (1722). Both are picaresque stories, in that each is a sequence of episodes held together largely because they happen to one person. But the central character in both novels is so convincing and set in so solid and specific a world that Defoe is often credited with being the first writer of “realistic” fiction. The first “novel of character” or psychological novel is Samuel Richardson’s Pamela (1740-41), an epistolary novel (or novel in which the narrative is conveyed entirely by an exchange of letters). It is a work characterized by the careful plotting of emotional states. Even more significant in this vein is Richardson’s masterpiece Clarissa (1747-48). Defoe and Richardson were the first great writers in our literature who did not take their plots from mythology, history, legend, or previous literature. They established the novel’s claim as an authentic account of the actual experience of individuals.

As far as I’m aware none of these novels are concerned with science or scientists for that matter. After all, science was still emerging from a period where alchemy reined supreme. One of the great European scientists, Isaac Newton (1642-1726/7), practiced alchemy along with his science. And that practice did not die with Newton.

With those provisos in mind, or not, do enjoy the movie reviews embedded in David’s April 17, 2015 news.  One final note,David in his weekly roundup of science on late night tv noted that Neil deGrasse Tyson’s late night tv talk show, Star Talks, debuted April 20, 2015, the episode can be seen again later this week while deGrasse Tyson continues to make the rounds of other talk shows to publicize his own.

Three Vancouver (Canada) science events: Vancouver Public Library on April 27, 2015, Café Scientifique on April 28, 2015, and the Wall Exchange on May 26, 2015

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Monday, April 27, 2015, 7:00 pm – 8:30 pm is a combined bee/poetry event at the main branch of the Vancouver Public Library. From the Vancouver Public Library “Honey, Hives, and Poetry in the City” event page,

Celebrate National Poetry Month by investigating food and poetry as a means of cultural and social activism and community building. Featured will be:

  • Rachel Rose, Poet Laureate of Vancouver
  • A collaborative reading by scientist and author Mark L. Winston (Bee Time: Lessons from the Hive) and award winning poet Renee Sarojini Saklikar (Children of Air India)
  • Readings from author and poet Elee Kraljii Gardiner and the Thursdays Writing Collective.
  • Presentation and honey tasting with Hives for Humanity.

Location:

Address: 350 West Georgia St.
VancouverV6B 6B1

  • Phone:

Location Details: Alice MacKay Room, Lower Level

[ETA April 21, 2015 at 1000 PST: I’ve just embedded a video which launches a new year of Science Rap Academy (Tom McFadden) in my April 21, 2015 post titled: Please, don’t kill my hive! (a Science Rap Academy production).]

*Change of Speaker for April 28, 2015  Café Scientifique, see Café Scientifique (Vancouver, Canada) makes a ‘happy’ change: new speaker for April 28, 2015 posting.”*

The day after the bee/poetry event, Tuesday, April 28, 2015  Café Scientifique, held in the back room of The Railway Club (2nd floor of 579 Dunsmuir St. [at Seymour St.], will be hosting a talk on pain (from the April 13, 2015 announcement,

Our speakers for the evening will be Dr. Matthew Ramer and Dr. John Kramer.  The title of their talk is:

Knowing Pains: How can we study pain to better treat it?

Pain is arguably the most useful of sensations.  It is nature’s way of telling us to stop doing whatever it is we are doing in order to prevent damage, and to protect injured body parts during the healing process.  In the absence of pain (in certain congenital conditions and in advanced diabetes, for example), the consequence can be loss of limbs and even of life.

There are circumstances, however, when pain serves no useful purpose:  it persists when the injury has healed or occurs in the absence of any frank tissue damage, and is inappropriate in context (previously innocuous stimuli become painful) and magnitude (mildly painful stimuli become excruciating).  This is called neuropathic pain and is incredibly difficult to treat because it is unresponsive to all of the drugs we use to treat normal, useful (“acute”) pain.

Ultimately, our research is aimed at finding new ways to minimise suffering from neuropathic pain.  Prerequisites to this goal include understanding how normal and neuropathic pain are encoded and perceived by the nervous system, and accurately measuring and quantifying pain so that we can draw reasonable conclusions about whether or not a particular treatment is effective.  We will discuss some historical and current ideas of how pain is transmitted from body to brain, and emphasize that the pain “channel” is not hard-wired, but like the process of learning, it is plastic, labile, and subject to “top-down” control.  We will also tackle the contentious issue of pain measurement in the clinic and laboratory.*

Both speakers are from iCORD (International Collaboration On Repair Discoveries), an interdisciplinary research centre focused on spinal cord injury located at Vancouver General Hospital. There’s more about Dr. Matt Ramer here and Dr. John Kramer here.

*Change of Speaker for April 28, 2015  Café Scientifique, see Café Scientifique (Vancouver, Canada) makes a ‘happy’ change: new speaker for April 28, 2015 posting.”*

The Wall Institute for Advanced Studies is bringing Dr. Bonnie Bassler, the bacteria whisperer, to speak in Vancouver. From the Wall Exchange series event page,

Dr. Bonnie Bassler, Molecular Biology, Princeton University

The Secret Social Lives of Bacteria

May 26, 2015
7:30 pm. Doors open at 6:30 pm.
Vogue Theatre, 918 Granville Street, Vancouver

Tickets available online, 2015 or by calling the Vogue Theatre Box Office: 604-569-1144

Learn more:

Bacterial behaviour may hold key to combatting antibiotic resistance
The Wall Papers

Here are some more details about the tickets, the event, and the speaker from the Northern Tickets event page,

Bonnie Bassler
The Secret, Social Lives of Bacteria
Vogue Theatre
Tuesday May 26th, 2015
Doors 6:30PM, Begins 7:30PM
Free Entry
**Tickets must be redeemed by 7:15PM to be valid**

Dr. Bonnie Bassler is an investigator with the Howard Hughes Medical Institute and Squibb Professor and Chair of the Department of Molecular Biology at Princeton University. The research in Dr. Bassler’s laboratory focuses on the chemical signaling mechanisms that bacteria use to communicate with each other known as “quorum sensing.” Therapies that block quorum sensing activity may represent an important new strategy for combating bacterial infections. Her research reveals new insights into the basic biology and ecology of bacteria; findings that may have direct application in the future treatment of disease.
…
Vogue Theatre
918 Granville Street – Vancouver

Go forth and enjoy!

* Removed ‘,t’ at very end of Café Scientifique excerpt on April 24, 2015.

Electrifying DNA (deoxyribonucleic acid)

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All kinds of things have electrical charges including DNA (deoxyribonucleic acid) according to an April 15, 2015 news item on Azonano,

Electrical charges not only move through wires, they also travel along lengths of DNA, the molecule of life. The property is known as charge transport.

In a new study appearing in the journal Nature Chemistry, authors, Limin Xiang, Julio Palma, Christopher Bruot and others at Arizona State University’s Biodesign Institute, explore the ways in which electrical charges move along DNA bases affixed to a pair of electrodes.

Their work reveals a new mechanism of charge transport that differs from the two recognized patterns in which charge either tunnels or hops along bases of the DNA chain.

An April 13, 2015 Arizona State University (ASU) news release (also on EurekAlert and dated April 14, 2015), which originated the news item, explains why this ‘blue sky’ research may prove important in the future,

Researchers predict that foundational work of this kind will have important implications in the design of a new generation of functional DNA-based electronic devices as well as providing new insights into health risks associated with transport-related damage to DNA.

Oxidative damage is believed to play a role in the initiation and progression of cancer. It is also implicated in neurodegenerative disorders like Alzheimer’s, Huntington’s disease and Parkinson’s disease and a range of other human afflictions.

…

An electron’s movements plays an important role in your body’s chemical reactions (from the news release),

The transfer of electrons is often regarded as the simplest form of chemical reaction, but nevertheless plays a critical role in a broad range of life-sustaining processes, including respiration and photosynthesis.

Charge transport can also produce negative effects on living systems, particularly through the process of oxidative stress, which causes damage to DNA and has been invoked in a broad range of diseases.

“When DNA is exposed to UV light, there’s a chance one of the bases– such as guanine–gets oxidized, meaning that it loses an electron,” Tao says. (Guanine is easier to oxidize than the other three bases, cytosine, thymine, and adenine, making it the most important base for charge transport.)

In some cases, the DNA damage is repaired when an electron migrates from another portion of the DNA strand to replace the missing one. DNA repair is a ceaseless, ongoing process, though a gradual loss of repair efficiency over time is one factor in the aging process. Oxidation randomly damages both RNA and DNA, which can interfere with normal cellular metabolism.

Radiation damage is also an issue for semiconductor devices, Tao notes–a factor that must be accounted for when electronics are exposed to high-energy particles like X rays, as in applications designed for outer space.

Researchers like Xiang and Tao hope to better understand charge transport through DNA, and the molecule provides a unique testing ground for observation. The length of a DNA molecule and its sequence of 4 nucleotides A, T, C and G can be readily modified and studies have shown that both alterations have an effect on how electrical charge moves through the molecule.

When the loss of an electron or oxidation occurs in DNA bases, a hole is left in place of the electron. This hole carries a positive charge, which can move along the DNA length under the influence of an electrical or magnetic field, just as an electron would. The movement of these positively charged holes along a stretch of DNA is the focus of the current study.

…

The news release goes on to describe charge transport,

Two primary mechanisms of charge transport have been examined in detail in previous research. Over short distances, an electron displays the properties of a wave, permitting it to pass straight through a DNA molecule. This process is a quantum mechanical effect known as tunneling.

Charge transport in DNA (and other molecules) over longer distances involves the process of hopping. When a charge hops from point to point along the DNA segment, it behaves classically and loses its wavelike properties. The electrical resistance is seen to increases exponentially during tunneling behavior and linearly, during hopping.

By attaching electrodes to the two ends of a DNA molecule, the researchers were able to monitor the passage of charge through the molecule, observing something new: “What we found in this particular paper is that there is an intermediate behavior,” Tao says. “It’s not exactly hopping because the electron still displays some of the wave properties.”

Instead, the holes observed in certain sequences of DNA are delocalized, spread over several base pairs. The effect is neither a linear nor exponential increase in electrical resistance but a periodic oscillation. The phenomenon was shown to be highly sequence dependent, with stacked base pairs of guanine-cytosine causing the observed oscillation.

Control experiments where G bases alternated, rather than occurring in a sequential stack, showed a linear increase in resistance with molecular length, in agreement with conventional hopping behavior.

A further property of DNA is also of importance in considering charge transport. The molecule at room temperature is not like a wire in a conventional electronic device, but rather is a highly dynamic structure, that writhes and fluctuates.

The last bit about writhing and fluctuating makes this work sound fascinating and very challenging.

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

Intermediate tunnelling–hopping regime in DNA charge transport by Limin Xiang, Julio L. Palma, Christopher Bruot, Vladimiro Mujica, Mark A. Ratner, & Nongjian Tao. Nature Chemistry 7, 221–226 (2015) doi:10.1038/nchem.2183 Published online 20 February 2015

This paper is behind a paywall.

Converting light to electricity at femto speeds

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This is a pretty remarkable (to me anyway) piece of research on speeding up the process of converting light to electricity. From an April 14, 2015 Institute of Photonic Science press release (also on EurekAlert but dated April 15, 2015),

The efficient conversion of light into electricity plays a crucial role in many technologies, ranging from cameras to solar cells. It also forms an essential step in data communication applications, since it allows for information carried by light to be converted into electrical information that can be processed in electrical circuits. Graphene is an excellent material for ultrafast conversion of light to electrical signals, but so far it was not known how fast graphene responds to ultrashort flashes of light.

…

The new device that the researchers developed is capable of converting light into electricity in less than 50 femtoseconds (a twentieth of a millionth of a millionth of a second). To do this, the researchers used a combination of ultrafast pulse-shaped laser excitation and highly sensitive electrical readout. As Klaas-Jan Tielrooij comments, “the experiment uniquely combined the ultrafast pulse shaping expertise obtained from single molecule ultrafast photonics with the expertise in graphene electronics. Facilitated by graphene’s nonlinear photo-thermoelectric response, these elements enabled the observation of femtosecond photodetection response times.”

The ultrafast creation of a photovoltage in graphene is possible due to the extremely fast and efficient interaction between all conduction band carriers in graphene. This interaction leads to a rapid creation of an electron distribution with an elevated electron temperature. Thus, the energy absorbed from light is efficiently and rapidly converted into electron heat. Next, the electron heat is converted into a voltage at the interface of two graphene regions with different doping. This photo-thermoelectric effect turns out to occur almost instantaneously, thus enabling the ultrafast conversion of absorbed light into electrical signals. As Prof. van Hulst states, “it is amazing how graphene allows direct non-linear detecting of ultrafast femtosecond (fs) pulses”.

The results obtained from the findings of this work, which has been partially funded by the EC Graphene Flagship, open a new pathway towards ultra-fast optoelectronic conversion. As Prof. Koppens comments, “Graphene photodetectors keep showing fascinating performances addressing a wide range of applications”.

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

Generation of photovoltage in graphene on a femtosecond timescale through efficient carrier heating by K. J. Tielrooij, L. Piatkowski, M. Massicotte, A. Woessner, Q. Ma, Y. Lee,  K. S. Myhro, C. N. Lau, P. Jarillo-Herrero, N. F. van Hulst & F. H. L. Koppens. Nature Nanotechnology (2015) doi:10.1038/nnano.2015.54 Published online 13 April 2015

This paper is behind a paywall but there is a free preview via ReadCube Access.

Ink toner on paper: research into topographies

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An April 14, 2015 news item on Nanowerk about pen (in this case, ink toner) and paper,

A team of Finnish scientists has found a new way to examine the ancient art of putting ink to paper in unprecedented 3-D detail. The technique could improve scientists’ understanding of how ink sticks to paper and ultimately lead to higher quality, less expensive and more environmentally-friendly printed products.

Using modern X-ray and laser-based technologies, the researchers created a nano-scale map of the varying thickness of toner ink on paper. They discovered that wood fibers protruding from the paper received relatively thin coatings of ink. In general, they also found the toner thickness was dictated mainly by the local changes in roughness, rather than the chemical variations caused by the paper’s uneven glossy finish.

…

“We believe that this gives new insight, especially on how the topography of paper impacts the ink setting or consolidation,” said Markko Myllys, an applied physicist at the University of Jyvaskyla in Finland. “This in turn helps us understand how glossy and non-glossy printed surfaces should be made.”

An April 14, 2016 American Institute of Physics (AIP) news release (also on EurekAlert) by Catherine Myers, which originated the news item, describes the research in more detail,

To achieve their detailed picture of ink thickness, the researchers first examined the underlying paper with X-ray microtomography, a smaller cousin of the CT scanning technology used in hospitals to produce images of the inside of the body.

To analyze the cyan ink layers, the researchers used two additional technologies: optical profilometry, which bounced a light beam off the surface of the ink to obtain a surface profile, and laser ablation, which zapped away controlled amounts of ink with a laser to determine the ink depth.

Although none of the imaging techniques are themselves new, the researchers were the first to combine all three to achieve a complete, high-resolution 3-D image of the intricate ink and paper microstructures.

The final images resemble a rugged mountain landscape, with the higher peaks generally showing thinner coatings of ink, and the valleys showing thicker pools.

The researchers found the typical ink layer was approximately 2.5 micrometers deep, about 1/40 the thickness of an average sheet of paper, but with relatively large spatial variations between the thickest and thinnest areas.

Knowing how topographical variations affect ink thickness will help the printing industry create more environmentally-friendly and less energy-demanding ink and optimize the size distribution of ink particles, Myllys said. It could also help the papermaking industry design more sustainable paper and packaging, for example from recycled components, while still maintaining the quality needed to make ink stick well. Additionally, the papermaking industry could use the findings to help decide how best to incorporate smart and novel features into paper, Myllys said.

The team believes the imaging methods they used can also be adapted to effectively analyze the thickness variations in other types of thin films, including those found in microelectronics, wear-resistant coatings and solar panels.

“This result can certainly be generalized, and that makes it actually quite interesting,” Myllys said. “Thickness variations of thin films are crucial in many applications, but the 3-D analysis has been very difficult or impossible until now.”

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

X-ray microtomography and laser ablation in the analysis of ink distribution in coated paper by  M. Myllys, H. Häkkänen, Korppi-Tommola, K. Backfolk, P. Sirviö, and J. Timonen1. J. Appl. Phys. 117, 144902 (2015); http://dx.doi.org/10.1063/1.4916588

This paper appears to be open access.

“No badge? No water!” at the Trottier Observatory opening (Simon Fraser University, Canada)

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Being refused a sip of water at a media event is one of those experiences that has you shaking your head in bemusement.  The event was held at Simon Fraser University (SFU)  on Friday, April 17, 2015* (today) between 10:30 and 11:30 am PST to celebrate the opening of the Trottier Observatory and Courtyard. Here’s how it was billed in the April 15, 2015 SFU media advisory I received,

What better way to celebrate the lead up to International Astronomy Week than the grand opening of a new observatory at Simon Fraser University?

Media are cordially invited to the grand opening of the Trottier Observatory and Science Courtyard, happening this Friday, April 17. This facility represents the most recent commitment by Lorne Trottier and Louise Rousselle Trottier towards science education at SFU.

A private event to formally open the observatory and recognize donor support will take place at SFU’s Burnaby campus on Friday, April 17 from 10:30-11:30 a.m. Members of the Trottier Family will be in attendance along with Government and other key VIPs. SFU will also host a public “Star Party” event to celebrate the grand opening during the evening.

SFU Physics professor Howard Trottier and his brother Lorne Trottier will be available for interviews on Friday, April 17th from 9:30-10:15 AM and from 11:30-12:30 PM.

WHAT:

–       Grand-opening of the Trottier Observatory and Science Courtyard

WHEN:

–       Friday, April 17

–       10:30-11:30 AM (Private Opening Ceremony and Site Tour)

7:00-11:00 PM (Public Star Party-currently full)

WHERE:

–       SFU’s Burnaby campus, 8888 University Drive, Burnaby, in front of Strand Hall

I hadn’t realized I was supposed to RSVP and so arrived to learn that I needed a badge to sit in the area for invited guests. Sadly, there was no fence to indicate where I might be free to stand. There were chairs for guests and it was very important that I not stand behind the chairs. This was a special standing zone for people with badges who could sit or stand wherever they liked. I, on the other hand, was allowed to stand back further in some mythical zone (about 18 inches away from the invited zone) where the unwashed were allowed to gaze longingly at the invitees.

Getting back to the observatory, a lot of thought seems to have been put into the design inside and outside. Unfortunately, there aren’t many details available as I can’t find anything more than this (scroll down about 75% of the way for the fact sheet) in the way of backgrounders, An April 12, 2015 article by Shawn Conner for the Vancouver Sun offers some details,

The facility features a large dome housing a 0.7-metre diameter (27-inch) reflector telescope, bigger than the one at the HR MacMillan Space Centre.

The observatory, Trottier [Howard Trottier, physics professor at SFU] says, is much more advanced since he visited his first one while in middle school.

“There’ve been a number of revolutions in telescopes,” the 55-year-old said. “Manufacturing costs are lower, much bigger telescopes are built. Even portable telescopes can be really quite big on a scale that was impossible when I was first into astronomy.”

One of the observatory’s features is a digital feed that community groups and schools across Canada can remotely access and deploy. Schools in B.C. will be invited to tender proposals to run the telescope from wherever they are.

Apparently, the plantings outside the observatory have an astronomical meaning. More immediately communicative are a series of four incised plaques which show the northern and southern skies in the autumn and spring respectively. Stone benches nearby also have meaning although what that might be is a mystery. Perhaps more information will become available online at SFU’s Trottier Observatory webspace.

As for my sip of water, I was gobsmacked when I was refused after standing in the sun for some 40 minutes or more (and a 1 hour transit trip) by Tamra Morley of SFU. Only invited people with badges were to be allowed water. She did note that there was water on campus elsewhere for me, although no directions were forthcoming.

Amusingly, Ms. Morley (who stood about 5’8″ in her shoes)* flung her arms out to either side making a barrier of her body while refusing me. For the record, on a good day I’m 5’4″. I’m also female and over the age of 60. And, there was more than enough water, coffee, and tea for invited and uninvited guests.

These things happen. Sometimes, the person just isn’t having  good day or is overzealous.

One final note, I met Kennedy Stewart, Member of Parliament and the New Democratic Party’s science critic at the event. He’s busy preparing for the upcoming election (either Spring or Fall 2015*) and hoping to get science policy included on the party’s 2015* election platform. I wish him good luck!

* ‘April 17, 2017’ changed to ‘April 17, 2015’; ‘Spring or Fall 2017’ changed to ‘Spring or Fall 2015’; ‘the party’s 2017 election platform’ changed to ‘the party’s 2015’ election platform and (who stood about 5’8″ in her shoes) added on April 17, 2015 at 1630 PST. Yikes, I seem invested in the year 2017.