Tag Archives: US

Using magnets to attract nanoparticles containing anesthesia

An April 11, 2014 news item on ScienceDaily, researchers describe a technique that would require far less anesthesia to numb the pain of various surgical procedures,

A technique using anesthesia-containing nanoparticles — drawn to the targeted area of the body by magnets — could one day provide a useful alternative to nerve block for local anesthesia in patients, suggests an experimental study in the April issue of Anesthesia & Analgesia, official journal of the International Anesthesia Research Society (IARS).

“We have established proof of principle that it is possible to produce ankle block in the rat by intravenous injection of magnetic nanoparticles associated with ropivacaine and magnet application at the ankle,” write Dr Venkat R.R. Mantha and colleagues of University of Pittsburgh School of Medicine. With further study, the nano-anesthesia technique might allow more potent doses of local anesthetics to be delivered safely during local anesthesia in humans.

The April 11, 2014 Walters Kluwer news release, which originated the news item, preliminary research,

The experimental pilot study evaluated the use of magnet-directed nanoparticles containing the local anesthetic drug ropivacaine (MNP/Ropiv) to produce anesthesia of the limbs.  The researchers engineered nanoparticle complexes containing small amounts of ropivacaine and the iron oxide mineral magnetite.  The MNP/Ropiv complexes were injected into the veins (intravenously, or IV) of anesthetized rats.

The researchers then placed magnets around the ankle of the right paw for 15, 30, or 60 minutes.  The goal was to use the magnets to draw the nanoparticles to ankle. Once there, the particles would release the anesthetic, numbing the nerves around the ankle.

Sensation in the right paw was assessed by comparing the right paw to the left paw, which was not affected. Other groups of rats received standard nerve block, with ropivacaine injected directly into the ankle; or IV injection of ropivacaine alone, not incorporated into nanoparticles.

Injection of MNP/Ropiv complexes followed by magnet application produced significant nerve block in the right ankle, similar to a standard nerve block.  The left ankle was unaffected.

The ankle block produced by MNP/Ropiv injection was greatest when the magnet was applied for 30 minutes—likely reflecting the time of maximum ropivacaine release.  High ropivacaine concentrations were found in right ankles of the MNP/Ropiv group, suggesting “sequestration of the drug locally by the magnet.”
 
In rats receiving MNP/Ropiv, the nanoparticles contained a total of 14 milligrams of ropivacaine—a dose high enough to cause potentially fatal toxic effects.  Yet none of the animals in the MNP/Ropiv group had apparent adverse effects of ropivacaine.  This was similar to the findings in rats receiving 1 milligram of plain ropivacaine.  Thus the safe dose of ropivacaine combined with nanoparticles could be at least 14 times higher, compared to IV ropivacaine alone.

Magnet-directed nanoparticles have previously been used for targeted delivery of chemotherapy drugs.  The new study suggests that a similar technique could be used to attract local anesthetic-containing nanoparticles to specific areas, as an alternative to local anesthetic block—like that used for foot and ankle surgery, for example.

Additional animal experiments would be needed before the MNP/Ropiv technique can be tested in humans.  But if it proved safe, the magnet-directed approach could provide a useful new alternative for regional anesthesia—delivering high concentrations of local anesthetics directly to the desired area, without increasing toxic effects.

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

Nanoanesthesia: A Novel, Intravenous Approach to Ankle Block in the Rat by Magnet-Directed Concentration of Ropivacaine-Associated Nanoparticles by Venkat R. R. Mantha, Harsha K. Nair, Raman Venkataramanan, Yuan Yue Gao, Krzysztof Matyjaszewski, Hongchen Dong, Wenwen Li, Doug Landsittel, Elan Cohen, William R. Lariviere. Anesthesia & Analgesia: doi: 10.1213/ANE.0000000000000175

This paper is open access.

UK’s Graphene NanoChem shares jump from 10p to 101p

Nick Fletcher in an April 7, 2014 posting on the Guardian’s MarketForcesLive blog provides a few tidbits about Graphene NanoChem,

The company [Graphene NanoChem] has formed a joint venture with Malaysia’s Scomi Oiltools and will licence its technology to produce a range of speciality chemicals. It has also signed an agreement with Emery advanced materials to develop chemicals for plastic additives, biolubricants and rubber.

Fletcher’s post provides more detail. You can also check out the Graphene NanoChem website and/or the Scomi Oilfield Services (aka Scomi Group) website. I think I finally tracked down the third company mentioned in the posting. Emery Advanced Materials seems to be part of Emery Oleochemicals Group based in Malyasia; I believe the parent company is based in the US. I have had problems linking to their site so found some information about Emery Oleochemicals on Bloomberg Business Week,

Emery Oleochemicals LLC produces natural-source oleochemical basestocks. It offers fatty acids, glycerin and triacetin, ozone acids, plastic additives, and ester-based oilfield chemicals. The company also provides sustainable polyol solutions for use in the manufacturing of flexible and rigid polyurethane foam that is used in transportation, construction, packaging, furniture, and bedding applications; and various coatings, adhesives, sealants, and elastomers applications. Emery Oleochemicals LLC was formerly known as Cognis Oleochemicals LLC and changed its name to Emery Oleochemicals LLC in May 2009. The company was founded in 2005 and is based in Cincinnati, Ohio. Emery Oleochemicals LLC …

So there you have it.

Nanomaterials and safety: Europe’s non-governmental agencies make recommendations; (US) Arizona State University initiative; and Japan’s voluntary carbon nanotube management

I have three news items which have one thing in common, they concern nanomaterials and safety. Two of these of items are fairly recent; the one about Japan has been sitting in my drafts folder for months and I’m including it here because if I don’t do it now, I never will.

First, there’s an April 7, 2014 news item on Nanowerk (h/t) about European non-governmental agencies (CIEL; the Center for International Environmental Law and its partners) and their recommendations regarding nanomaterials and safety. From the CIEL April 2014 news release,

CIEL and European partners* publish position paper on the regulation of nanomaterials at a meeting of EU competent authorities

*ClientEarth, The European Environmental Bureau, European citizen’s Organization for Standardisation, The European consumer voice in Standardisation –ANEC, and Health Care Without Harm, Bureau of European Consumers

… Current EU legislation does not guarantee that all nanomaterials on the market are safe by being assessed separately from the bulk form of the substance. Therefore, we ask the European Commission to come forward with concrete proposals for a comprehensive revision of the existing legal framework addressing the potential risks of nanomaterials.

1. Nanomaterials are different from other substances.

We are concerned that EU law does not take account of the fact that nano forms of a substance are different and have different intrinsic properties from their bulk counterpart. Therefore, we call for this principle to be explicitly established in the REACH, and Classification Labeling and Packaging (CLP) regulations, as well as in all other relevant legislation. To ensure adequate consideration, the submission of comprehensive substance identity and characterization data for all nanomaterials on the market, as defined by the Commission’s proposal for a nanomaterial definition, should be required.

Similarly, we call on the European Commission and EU Member States to ensure that nanomaterials do not benefit from the delays granted under REACH to phase-in substances, on the basis of information collected on their bulk form.

Further, nanomaterials, due to their properties, are generally much more reactive than their bulk counterpart, thereby increasing the risk of harmful impact of nanomaterials compared to an equivalent mass of bulk material. Therefore, the present REACH thresholds for the registration of nanomaterials should be lowered.

Before 2018, all nanomaterials on the market produced in amounts of over 10kg/year must be registered with ECHA on the basis of a full registration dossier specific to the nanoform.

2. Risk from nanomaterials must be assessed

Six years after the entry into force of the REACH registration requirements, only nine substances have been registered as nanomaterials despite the much wider number of substances already on the EU market, as demonstrated by existing inventories. Furthermore, the poor quality of those few nano registration dossiers does not enable their risks to be properly assessed. To confirm the conclusions of the Commission’s nano regulatory review assuming that not all nanomaterials are toxic, relevant EU legislation should be amended to ensure that all nanomaterials are adequately assessed for their hazardous properties.

Given the concerns about novel properties of nanomaterials, under REACH, all registration dossiers of nanomaterials must include a chemical safety assessment and must comply with the same information submission requirements currently required for substances classified as Carcinogenic, Mutagenic or Reprotoxic (CMRs).

3. Nanomaterials should be thoroughly evaluated

Pending the thorough risk assessment of nanomaterials demonstrated by comprehensive and up-to-date registration dossiers for all nanoforms on the market, we call on ECHA to systematically check compliance for all nanoforms, as well as check the compliance of all dossiers which, due to uncertainties in the description of their identity and characterization, are suspected of including substances in the nanoform. Further, the Community Roling Action Plan (CoRAP) list should include all identified substances in the nanoform and evaluation should be carried out without delay.

4. Information on nanomaterials must be collected and disseminated

All EU citizens have the right to know which products contain nanomaterials as well as the right to know about their risks to health and environment and overall level of exposure. Given the uncertainties surrounding nanomaterials, the Commission must guarantee that members of the public are in a position to exercise their right to know and to make informed choices pending thorough risk assessments of nanomaterials on the market.

Therefore, a publicly accessible inventory of nanomaterials and consumer products containing nanomaterials must be established at European level. Moreover, specific nano-labelling or declaration requirements must be established for all nano-containing products (detergents, aerosols, sprays, paints, medical devices, etc.) in addition to those applicable to food, cosmetics and biocides which are required under existing obligations.

5. REACH enforcement activities should tackle nanomaterials

REACH’s fundamental principle of “no data, no market” should be thoroughly implemented. Therefore, nanomaterials that are on the market without a meaningful minimum set of data to allow the assessment of their hazards and risks should be denied market access through enforcement activities. In the meantime, we ask the EU Member States and manufacturers to use a precautionary approach in the assessment, production, use and disposal of nanomaterials

This comes on the heels of CIEL’s March 2014 news release announcing a new three-year joint project concerning nanomaterials and safety and responsible development,

Supported by the VELUX foundations, CIEL and ECOS (the European Citizen’s Organization for Standardization) are launching a three-year project aiming to ensure that risk assessment methodologies and risk management tools help guide regulators towards the adoption of a precaution-based regulatory framework for the responsible development of nanomaterials in the EU and beyond.

Together with our project partner the German Öko-Institut, CIEL and ECOS will participate in the work of the standardization organizations Comité Européen de Normalisation and International Standards Organization, and this work of the OECD [Organization for Economic Cooperation and Development], especially related to health, environmental and safety aspects of nanomaterials and exposure and risk assessment. We will translate progress into understandable information and issue policy recommendations to guide regulators and support environmental NGOs in their campaigns for the safe and sustainable production and use of nanomaterials.

The VILLUM FOUNDATION and the VELUX FOUNDATION are non-profit foundations created by Villum Kann Rasmussen, the founder of the VELUX Group and other entities in the VKR Group, whose mission it is to bring daylight, fresh air and a better environment into people’s everyday lives.

Meanwhile in the US, an April 6, 2014 news item on Nanowerk announces a new research network, based at Arizona State University (ASU), devoted to studying health and environmental risks of nanomaterials,

Arizona State University researchers will lead a multi-university project to aid industry in understanding and predicting the potential health and environmental risks from nanomaterials.

Nanoparticles, which are approximately 1 to 100 nanometers in size, are used in an increasing number of consumer products to provide texture, resiliency and, in some cases, antibacterial protection.

The U.S. Environmental Protection Agency (EPA) has awarded a grant of $5 million over the next four years to support the LCnano Network as part of the Life Cycle of Nanomaterials project, which will focus on helping to ensure the safety of nanomaterials throughout their life cycles – from the manufacture to the use and disposal of the products that contain these engineered materials.

An April 1, 2014 ASU news release, which originated the news item, provides more details and includes information about project partners which I’m happy to note include nanoHUB and the Nanoscale Informal Science Education Network (NISENet) in addition to the other universities,

Paul Westerhoff is the LCnano Network director, as well as the associate dean of research for ASU’s Ira A. Fulton Schools of Engineering and a professor in the School of Sustainable Engineering and the Built Environment.

The project will team engineers, chemists, toxicologists and social scientists from ASU, Johns Hopkins, Duke, Carnegie Mellon, Purdue, Yale, Oregon’s state universities, the Colorado School of Mines and the University of Illinois-Chicago.

Engineered nanomaterials of silver, titanium, silica and carbon are among the most commonly used. They are dispersed in common liquids and food products, embedded in the polymers from which many products are made and attached to textiles, including clothing.

Nanomaterials provide clear benefits for many products, Westerhoff says, but there remains “a big knowledge gap” about how, or if, nanomaterials are released from consumer products into the environment as they move through their life cycles, eventually ending up in soils and water systems.

“We hope to help industry make sure that the kinds of products that engineered nanomaterials enable them to create are safe for the environment,” Westerhoff says.

“We will develop molecular-level fundamental theories to ensure the manufacturing processes for these products is safer,” he explains, “and provide databases of measurements of the properties and behavior of nanomaterials before, during and after their use in consumer products.”

Among the bigger questions the LCnano Network will investigate are whether nanomaterials can become toxic through exposure to other materials or the biological environs they come in contact with over the course of their life cycles, Westerhoff says.

The researchers will collaborate with industry – both large and small companies – and government laboratories to find ways of reducing such uncertainties.

Among the objectives is to provide a framework for product design and manufacturing that preserves the commercial value of the products using nanomaterials, but minimizes potentially adverse environmental and health hazards.

In pursuing that goal, the network team will also be developing technologies to better detect and predict potential nanomaterial impacts.

Beyond that, the LCnano Network also plans to increase awareness about efforts to protect public safety as engineered nanomaterials in products become more prevalent.

The grant will enable the project team to develop educational programs, including a museum exhibit about nanomaterials based on the LCnano Network project. The exhibit will be deployed through a partnership with the Arizona Science Center and researchers who have worked with the Nanoscale Informal Science Education Network.

The team also plans to make information about its research progress available on the nanotechnology industry website Nanohub.org.

“We hope to use Nanohub both as an internal virtual networking tool for the research team, and as a portal to post the outcomes and products of our research for public access,” Westerhoff says.

The grant will also support the participation of graduate students in the Science Outside the Lab program, which educates students on how science and engineering research can help shape public policy.

Other ASU faculty members involved in the LCnano Network project are:

• Pierre Herckes, associate professor, Department of Chemistry and Biochemistry, College of Liberal Arts and Sciences
• Kiril Hristovski, assistant professor, Department of Engineering, College of Technology and Innovation
• Thomas Seager, associate professor, School of Sustainable Engineering and the Built Environment
• David Guston, professor and director, Consortium for Science, Policy and Outcomes
• Ira Bennett, assistant research professor, Consortium for Science, Policy and Outcomes
• Jameson Wetmore, associate professor, Consortium for Science, Policy and Outcomes, and School of Human Evolution and Social Change

I hope to hear more about the LCnano Network as it progresses.

Finally, there was this Nov. 12, 2013 news item on Nanowerk about instituting  voluntary safety protocols for carbon nanotubes in Japan,

Technology Research Association for Single Wall Carbon Nanotubes (TASC)—a consortium of nine companies and the National Institute of Advanced Industrial Science and Technology (AIST) — is developing voluntary safety management techniques for carbon nanotubes (CNTs) under the project (no. P10024) “Innovative carbon nanotubes composite materials project toward achieving a low-carbon society,” which is sponsored by the New Energy and Industrial Technology Development Organization (NEDO).

Lynn Bergeson’s Nov. 15, 2013 posting on nanotech.lawbc.com provides a few more details abut the TASC/AIST carbon nanotube project (Note: A link has been removed),

Japan’s National Institute of Advanced Industrial Science and Technology (AIST) announced in October 2013 a voluntary guidance document on measuring airborne carbon nanotubes (CNT) in workplaces. … The guidance summarizes the available practical methods for measuring airborne CNTs:  (1) on-line aerosol measurement; (2) off-line quantitative analysis (e.g., thermal carbon analysis); and (3) sample collection for electron microscope observation. …

You can  download two protocol documents (Guide to measuring airborne carbon nanotubes in workplaces and/or The protocols of preparation, characterization and in vitro cell based assays for safety testing of carbon nanotubes), another has been published since Nov. 2013, from the AIST’s Developing voluntary safety management techniques for carbon nanotubes (CNTs): Protocol and Guide webpage., Both documents are also available in Japanese and you can link to the Japanese language version of the site from the webpage.

Sing a song of science literacy

Let’s applaud the American Educational Research Association for its plan to livestream part of its 2014 conference being held April 3 – 6, 2014 for free (you do have to register; pause for applause). Unfortunately, the one session I’d really like to hear is not one of the chosen ones. It’s the “Sing about Science: Leveraging the Power of Music to Improve Science Education” session being delivered by two researchers from the University of Washington (UW; state). From the April 2, 2014 UW news release (also on EurekAlert),

As the United States puts ever-greater emphasis on science, technology, engineering and mathematics education to keep competitive in the global economy, schools are trying to figure out how to improve student learning in science.

University of Washington researchers Katie Davis and Greg Crowther think music may be the answer for some kids. They studied the ability of music videos to enhance students’ understanding of scientific concepts.

Davis will present “Sing about Science: Leveraging the Power of Music to Improve Science Education” on Friday (April 4) at the American Educational Research Association’s annual conference.

Davis and Crowther aren’t just talking about music as a mnemonic device to help students memorize facts. Previous research has shown that music can reduce stress and increase student engagement in the learning process, so the researchers theorized that music videos could help some students process and retain information better.

“It makes sense that we shouldn’t teach all kids in the same way; we should individualize,” said Davis, an assistant professor in the UW’s Information School. “We need to provide multiple entry points in all subject matters. Music is a different entry point into scientific concepts.”

Crowther is a biologist but is so interested in music that 10 years ago he created a website with a database of songs about science and math; SingAboutScience.org now has links to more than 7,000 of them (the majority do not have video). Teachers can type in a topic and find music relevant to what they are teaching.

For their current research, they set up laptop computers at five science-related outreach events in Washington state. Most targeted students in K-12, but adults also participated. Participants in the study ranged from 3 to 76 years old, with a median age of 12. Each person sat in front of a laptop and selected a science-based music video to watch.

For instance, one video is titled “Fossil Rock Anthem,” and is a parody of the hip-hop song “Party Rock Anthem.” It shows a dancing archaeologist, graphics of fossils and ground striations and continental plates drifting. It’s a catchy tune with fun, colorful graphics.

Participants took a pre-video quiz of four questions related to information in the video, plus a bonus question not covered by the video. They were also asked to rate their confidence in their answers. They were randomly assigned to watch either a visually-rich music video or a music video that showed only the lyrics on screen. Then they took a post-video quiz that included the same content and confidence questions.

In two-thirds of the music videos (10 out of 15), participants had more correct answers after watching the videos. Quiz scores rose by an average of one more correct answer after watching the videos. The lyrics-only music videos were as beneficial to improving quiz scores as the visually-rich videos.

Participants improved their scores not only on factoid-type questions, but also the more complex comprehension questions, which shows that the videos improved people’s scientific understanding and not just memorization.

Pre- and post-quiz scores were no different for the bonus questions, which did not cover material from the videos. This finding suggests that the boost in quiz scores was due to watching the video, and not by some other variable.

The researchers say everyone learns in different ways, and past research has shown that students learn best with hands-on, personally relevant tools that utilize powers of observation and audio-visuals. They also note that a person’s memories can change based on an emotionally charged atmosphere. Since music is an emotional medium, it makes sense that our educational memory could be enhanced by it.

“We’re not saying this is the only way you should teach science, it’s just a different way,” Davis said. “We’re hoping it can engage a broader array of students, to help them find success and create identities as science learners.”

Added Crowther, “There wasn’t a teacher breathing down students’ necks telling them they had to learn this for a test. People voluntarily watched these videos for fun. This is exactly the type of opportunity we should be creating more of. Students will seek it out just because it’s fun and interesting.”

I went to Crowther’s website, Sing About Science (be careful, you may spend more time on the website than you planned), and picked this video from the listing,

It makes me think of protest songs from the 1960s. Here’s more about the video from its YouTube home,

Uploaded on Feb 25, 2011

NIMBioS Songwriter-in-Residence RB Morris performs his song “Science for the People.” For more information about the Songwriter-in-Residence program at the National Institute for Mathematical and Biological Synthesis (NIMBioS), visit http://www.nimbios.org/songwriter

I most recently mentioned NIMBioS in a November 1, 2013 interview with Canadian rapper and science afficionado, Baba Brinkman who has also been one of their artists-in-residence.

Xerox Research Centre Canada, authentic currency, etc. and a ‘nano’ deal with Authentix

An April 1, 2014 news item on labcanada.com describes a recently signed deal which may turn up the competition in Canada’s currency authentication business sector,

The Xerox Research Centre Canada [XRCC] says it has signed a multi-year materials research services agreement with Dallas-based Authentix, a provider of anti-counterfeiting, brand protection and program integrity solutions for the oil and gas industry; currency, branded products and tax stamp markets.

“Working with companies like Authentix adds to the value our scientists bring to the research world,” said Paul Smith, vice president and director of the Xerox Research Centre Canada. “Not only do we continue to strengthen our scientific role in Canadian innovation, we are now bringing valuable research capabilities to other companies globally.”

Given that Xerox is a US company with a Canadian branch, I’m not sure how signing a deal with another US company aids Canadian innovation. On the plus side, it does give some Canadian scientists a job.

I also noted the reference to “currency authentication”, which suggests that Authentix could be in direct competition with the Canadian company, Nanotech Security Corp. (I have written about Nanotech Security Corp. previously with the two most recent being a Jan. 31, 2014 posting about the company’s presentation at an Optical Document Security Conference and a March 17, 2014 posting about the company’s first commercial client, TED.) Perhaps Xerox plans to spur Canadian innovation by providing more competition for our technology companies.

Here’s more from the March 31, 2014 Xerox news release, which originated the news item about the deal with Authentix,

Scientists at XRCC specialize in the design and development of electronic materials and specialty components; environmentally-friendly processes; coatings, applied nanotechnology; polymer science, engineering and pilot plant scale-up. [emphasis mine]

“Materials science research makes it possible to bring new levels of security, accuracy and efficiency to product authentication,” said Jeff Conroy, chief technology officer of Authentix.  “Leveraging the core competencies of Xerox’s materials lab in Canada expands and accelerates our ability to bring innovative solutions to the authentication market.”

Located near Toronto, XRCC is part of the global Xerox Innovation Group made up of researchers and engineers in five world-renowned research centers. Each center leverages XRCC’s unique, integrated, global materials research and development mandate.

You can find out more about Authentix here.

Getting back to XRCC, they had a longstanding relationship with Canada’s National Institute of Nanotechnology (NINT) having signed a 2007 contract with NINT and the Government of Alberta, from a Xerox Innovation Story,

In Canada’s first major public-private nanotechnology research partnership, the Xerox Research Centre of Canada (XRCC), NRC National Institute for Nanotechnology (NINT) and Government of Alberta will provide approximately $4.5 million for research and development of materials-based nanotechnology over the next three years.

The three partners will invest funds, human resources, and available infrastructures to create a research program and teams focused on developing commercially successful nanotechnology-based discoveries. Personnel from NINT and XRCC will collaborate on research projects at NINT in Edmonton, Alberta, and at XRCC in Mississauga, Ontario.

The funds will contribute to the hiring of eight to 10 scientists who will investigate materials-based nanotechnologies, including document- and display-related technologies. The research program, co-managed by XRCC and NINT, will allow access to Xerox’s experience in successfully commercializing technology to facilitate the market application of resulting inventions.

“This level of public and private sector partnership helps fuel the type of innovation that will keep Alberta, and Canada as a whole, strong and competitive in an increasingly global, knowledge-based economy,” said Doug Horner, minister for Advanced Education and Technology, Government of Alberta. “The investments from the Government of Alberta, Xerox and NINT will build a world-class nanotechnology research program that embraces the spirit of innovation, but also that of commercialization.”

I find the references to Xerox and innovation and commercialization amusing since the company is famous for its innovation missteps. For example, the company owned the photocopying business from the 1960s into the 1970s due to its patent rights but once those rights ran out (there’s usually a time limit on a patent) the company was poorly equipped to compete. My guess is that they didn’t know how in an environment where they no longer held a monopoly. The other famous story concerns the mouse and the graphical user interface both of which were developed at Xerox but the company never pursued those innovations leaving Stephen Jobs and his colleagues to found Apple.

At any rate, Xerox survived those missteps so perhaps they learned something and they really do mean it when they talk about spurring innovation. Although, given the business model for most Canadian technology companies, I expect Nanotech Security Corp. to get purchased by Authentix or one of its competitors with the consequence that Canadian taxpayers have helped to pay, yet again, for innovation that will be purchased by a corporate entity with headquarters in another country and much less interest in maintaining a business presence in Canada. If you think I’m being cynical about another country’s corporate interests in Canada, take a look at this excerpt from Derrick Penner’s March 28, 2014 article for the Vancouver Sun about Vancouver’s recent Globe 2014 conference,

Globe, the biannual conference on sustainable development [March 26 - 28, 2014], is as much about doing business as it is about discussing bright ideas for reducing the impact of industry on the environment.

And a new twist for European delegates, such as Roumeas [Vincent Roumeas, a business development manager for the Paris Region Economic Development Agency], is the prospect of Canada Europe Free Trade.

Prime Minister Stephen Harper and European Commission President José Manuel Barroso, last October, signed an agreement in principal, which commits the two sides to finalizing a full agreement giving each other tariff-free access to each others’ markets.

Roumeas said it is too soon to tell how much of a draw EU free trade will be because he is working on developing immediate prospects within the next 18 months, which would be before any benefits from free trade would kick in, if the deal is concluded.

However, his colleague Jeremy Bernard Orawiec, a trade adviser for UbiFrance, does see the agreement as an attraction for French firms interested the American market.

He added that the U.S. is viewed as a tough market to crack, so Canada is looked at as an easier-accessed entry point to all of North America.

“It’s really positive to see Canada able to make an agreement before the U.S.,” Orawiec said. “It gives us a time frame so (companies) can come here [Canada] and explore the whole American market.” [emphases mine]

It’s not clear from his comments but I suspect Orawiec is unaware that Mexico is part of North America. In any event, Canada as a market place or as an innovation centre is not important in and of itself. One can criticize Orawiec for making those comments but I’d like to thank him as he has expressed an attitude that I believe is widely held.

Storing isotopes in nanocontainers for safer radiation therapy

While it can be effective, radiation therapy is known to be destructive  for cancerous cells and healthy cells. Researchers at Kansas State University and their colleagues in other institutions have devised a new technique that contains the isotopes so they reach the cancerous cells only. From an April 2, 2014 news item in ScienceDaily,

Researchers have discovered that microscopic “bubbles” developed at Kansas State University are safe and effective storage lockers for harmful isotopes that emit ionizing radiation for treating tumors.

The findings can benefit patient health and advance radiation therapy used to treat cancer and other diseases, said John M. Tomich, a professor of biochemistry and molecular biophysics who is affiliated with the university’s Johnson Cancer Research Center.

Tomich conducted the study with Ekaterina Dadachova, a radiochemistry specialist at Albert Einstein College of Medicine in New York, along with researchers from his group at Kansas State University, the University of Kansas, Jikei University School of Medicine in Japan and the Institute for Transuranium Elements in Germany. They recently published their findings in the study “Branched Amphiphilic Peptide Capsules: Cellular Uptake and Retention of Encapsulated Solutes,” which appears in the scientific journal Biochimica et Biophysica Acta.

The study looks at the ability of nontoxic molecules to store and deliver potentially harmful alpha emitting radioisotopes — one of the most effective forms of radiation therapy.

An April 2, 2014 Kansas State University news release (also on EurekAlert), which originated the news item, provides more details about this research that in some ways dates from 2012,

The study looks at the ability of nontoxic molecules to store and deliver potentially harmful alpha emitting radioisotopes — one of the most effective forms of radiation therapy.

In 2012, Tomich and his research lab team combined two related sequences of amino acids to form a very small, hollow nanocapsule similar to a bubble.

“We found that the two sequences come together to form a thin membrane that assembled into little spheres, which we call capsules,” Tomich said. “While other vesicles have been created from lipids, most are much less stable and break down. Ours are like stones, though. They’re incredibly stable and are not destroyed by cells in the body.”

The ability of the capsules to stay intact with the isotope inside and remain undetected by the body’s clearance systems prompted Tomich to investigate using the capsules as unbreakable storage containers that can be used for biomedical research, particularly in radiation therapies.

“The problem with current alpha-particle radiation therapies used to treat cancer is that they lead to the release of nontargeted radioactive daughter ions into the body,” Tomich said. “Radioactive atoms break down to form new atoms, called daughter ions, with the release of some form of energy or energetic particles. Alpha emitters give off an energetic particle that comes off at nearly the speed of light.”

These particles are like a car careening on ice, Tomich said. They are very powerful but can only travel a short distance. On collision, the alpha particle destroys DNA and whatever vital cellular components are in its path. Similarly, the daughter ions recoil with high energy on ejection of the alpha particle — similar to how a gun recoils as it is fired. The daughter ions have enough energy to escape the targeting and containment molecules that currently are in use.

“Once freed, the daughter isotopes can end up in places you don’t want them, like bone marrow, which can then lead to leukemia and new challenges,” Tomich said. “We don’t want any stray isotopes because they can harm the body. The trick is to get the radioactive isotopes into and contained in just diseases cells where they can work their magic.”

The radioactive compound that the team works with is 225Actinium, which on decay releases four alpha particles and numerous daughter ions.

Tomich and Dadachova tested the retention and biodistribution of alpha-emitting particles trapped inside the peptide capsules in cells. The capsules readily enter cells. Once inside, they migrate to a position alongside the nucleus, where the DNA is.

Tomich and Dadachova found that as the alpha particle-emitting isotopes decayed, the recoiled daughter ion collides with the capsule walls and essentially bounces off them and remains trapped inside the capsule. This completely blocked the release of the daughter ions, which prevented uptake in certain nontarget tissues and protected the subject from harmful radiation that would have otherwise have been releases into the body.

Tomich said that more studies are needed to add target molecules to the surface of the capsules. He anticipates that this new approach will provide a safer option for treating tumors with radiation therapy by reducing the amount of radioisotope required for killing the cancer cells and reducing the side effects caused by off-target accumulation of the radioisotopes.

“These capsules are easy to make and easy to work with,” Tomich said. “I think we’re just scratching the surface of what we can do with them to improve human health and nanomaterials.”

I hope this new technique proves effective and travels soon from the laboratory to clinical practice in the foreseeable future.

In the meantime, here’s a link to and a citation for the paper,

Branched amphiphilic peptide capsules: Cellular uptake and retention of encapsulated solutes by Pinakin Sukthankar, L. Adriana Avila, Susan K. Whitaker, Takeo Iwamoto, Alfred Morgenstern, Christos Apostolidis, Ke Liu, Robert P. Hanzlik, Ekaterina Dadachova, and John M. Tomich. Biochimica et Biophysica Acta (BBA) – Biomembranes (Biochim Biophys Acta) 2014 Feb 22. pii: S0005-2736(14)00069-8. doi: 10.1016/j.bbamem.2014.02.005. Available online 22 February 2014

This paper is behind a paywall.

Researchers at Purdue University (Indiana, US) and at the Indian Institute of Technology Madras (Chennai, India) develop Star Trek-type ‘tricorders’

To be clear, the Star Trek-type ‘tricorder’ referred to in the heading is, in fact, a hand-held spectrometer and the research from Purdue University and the Indian Institute of Technology Madras represents a developmental leap forward, not a new product. From a March 26, 2014 news item on Azonano,

Nanotechnology is advancing tools likened to Star Trek’s “tricorder” that perform on-the-spot chemical analysis for a range of applications including medical testing, explosives detection and food safety.

Researchers found that when paper used to collect a sample was coated with carbon nanotubes, the voltage required was 1,000 times reduced, the signal was sharpened and the equipment was able to capture far more delicate molecules.

Dexter Johnson in his March 26, 2014 posting (Nanoclast blog on the IEEE [Institute of Electrical and Electronics Engineers] website) provides some background information about the race to miniaturize spectrometers (Note: A link has been removed),

Recent research has been relying on nanomaterials to build smaller spectrometers. Late last year, a group at the Technische Universität Dresden and the Fraunhofer Institute in Germany developed a novel, miniature spectrometer, based on metallic nanowires, that was small enough to fit into a mobile phone.

Dexter goes on to provide a summary about this latest research, which I strongly recommend reading, especially if you don’t have the patience to read the rest of the news release. The March 25, 2014 Purdue University news release by Elizabeth K. Gardner, which originated the news item, provides insight from the researchers,

“This is a big step in our efforts to create miniature, handheld mass spectrometers for the field,” said R. Graham Cooks, Purdue’s Henry B. Hass Distinguished Professor of Chemistry. “The dramatic decrease in power required means a reduction in battery size and cost to perform the experiments. The entire system is becoming lighter and cheaper, which brings it that much closer to being viable for easy, widespread use.”

Cooks and Thalappil Pradeep, a professor of chemistry at the Indian Institute of Technology Madras, Chennai, led the research.

“Taking science to the people is what is most important,” Pradeep said. “Mass spectrometry is a fantastic tool, but it is not yet on every physician’s table or in the pocket of agricultural inspectors and security guards. Great techniques have been developed, but we need to hone them into tools that are affordable, can be efficiently manufactured and easily used.”

The news release goes on to describe the research,

The National Science Foundation-funded study used an analysis technique developed by Cooks and his colleagues called PaperSpray™ ionization. The technique relies on a sample obtained by wiping an object or placing a drop of liquid on paper wet with a solvent to capture residues from the object’s surface. A small triangle is then cut from the paper and placed on a special attachment of the mass spectrometer where voltage is applied. The voltage creates an electric field that turns the mixture of solvent and residues into fine droplets containing ionized molecules that pop off and are vacuumed into the mass spectrometer for analysis. The mass spectrometer then identifies the sample’s ionized molecules by their mass.

The technique depends on a strong electric field and the nanotubes act like tiny antennas that create a strong electric field from a very small voltage. One volt over a few nanometers creates an electric field equivalent to 10 million volts over a centimeter, Pradeep said.

“The trick was to isolate these tiny, nanoscale antennae and keep them from bundling together because individual nanotubes must project out of the paper,” he said. “The carbon nanotubes work well and can be dispersed in water and applied on suitable substrates.”

The Nano Mission of the Government of India supported the research at the Indian Institute of Technology Madras and graduate students Rahul Narayanan and Depanjan Sarkar performed the experiments.

In addition to reducing the size of the battery required and energy cost to run the tests, the new technique also simplified the analysis by nearly eliminating background noise, Cooks said.

“Under these conditions, the analysis is nearly noise free and a sharp, clear signal of the sample is delivered,” he said. “We don’t know why this is – why background molecules that surround us in the air or from within the equipment aren’t being ionized and entering into the analysis. It’s a puzzling, but pleasant surprise.”

The reduced voltage required also makes the method gentler than the standard PaperSpray™ ionization techniques.

“It is a very soft method,” Cooks said. “Fragile molecules and complexes are able to hold together here when they otherwise wouldn’t. This could lead to other potential applications.”

The team plans to investigate the mechanisms behind the reduction in background noise and potential applications of the gentle method, but the most promising aspect of the new technique is its potential to miniaturize the mass spectrometry system, Cooks said.

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

Molecular Ionization from Carbon Nanotube Paper by Rahul Narayanan, Depanjan Sarkar, Prof. R. Graham Cooks, and Prof. Thalappil Pradeep. Angewandte Chemie International Edition Article first published online: 18 MAR 2014 DOI: 10.1002/anie.201311053

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

Wilkinson Prize for numerical software: call for 2015 submissions

The Wilkinson Prize is not meant to recognize a nice, shiny new algorithm, rather it’s meant for the implementation phase and, as anyone who have ever been involved in that phase of a project can tell you, that phase is often sadly neglected. So, bravo for the Wilkinson Prize!

From the March 27, 2014 Numerical Algorithms Group (NAG) news release, here’s a brief history of the Wilkinson Prize,

Every four years the Numerical Algorithms Group (NAG), the National Physical Laboratory (NPL) and Argonne National Laboratory award the prestigious Wilkinson Prize in honour of the outstanding contributions of Dr James Hardy Wilkinson to the field of numerical software. The next Wilkinson Prize will be awarded at the [2015] International Congress on Industrial and Applied Mathematics in Beijing, and will consist of a $3000 cash prize.

NAG, NPL [UK National Physical Laboratory] and Argonne [US Dept. of Energy, Argonne National Laboratory] are committed to encouraging innovative, insightful and original work in numerical software in the same way that Wilkinson inspired many throughout his career. Wilkinson worked on the Automatic Computing Engine (ACE) while at NPL and later authored numerous papers on his speciality, numerical analysis. He also authored many of the routines for matrix computation in the early marks of the NAG Library.

The most recent Wilkinson Prize was awarded in 2011 to Andreas Waechter and Carl D. Laird for IPOPT. Commenting on winning the Wilkinson Prize Carl D. Laird, Associate Professor at the School of Chemical Engineering, Purdue University, said “I love writing software, and working with Andreas on IPOPT was a highlight of my career. From the beginning, our goal was to produce great software that would be used by other researchers and provide solutions to real engineering and scientific problems.

The Wilkinson Prize is one of the few awards that recognises the importance of implementation – that you need more than a great algorithm to produce high-impact numerical software. It rewards the tremendous effort required to ensure reliability, efficiency, and usability of the software.

Here’s more about the prize (list of previous winners, eligibility, etc.), from the Wilkinson Prize for Numerical Software call for submissions webpage,

Previous Prize winners:

  • 2011: Andreas Waechter and Carl D. Laird for Ipopt
  • 2007: Wolfgang Bangerth for deal.II
  • 2003: Jonathan Shewchuch for Triangle
  • 1999: Matteo Frigo and Steven Johnson for FFTW.
  • 1995: Chris Bischof and Alan Carle for ADIFOR 2.0.
  • 1991: Linda Petzold for DASSL.

Eligibility

The prize will be awarded to the authors of an outstanding piece of numerical software, or to individuals who have made an outstanding contribution to an existing piece of numerical software. In the latter case applicants must clearly be able to distinguish their personal contribution and to have that contribution authenticated, and the submission must be written in terms of that personal contribution and not of the software as a whole. To encourage researchers in the earlier stages of their career all applicants must be at most 40 years of age on January 1, 2014.
Rules for Submission

Each entry must contain the following:

Software written in a widely available high-level programming language.
A two-page summary of the main features of the algorithm and software implementation.
A paper describing the algorithm and the software implementation. The paper should give an analysis of the algorithm and indicate any special programming features.
Documentation of the software which describes its purpose and method of use.
Examples of use of the software, including a test program and data.

Submissions

The preferred format for submissions is a gzipped, tar archive or a zip file. Please contact us if you would like to use a different submission mechanism. Submissions should include a README file describing the contents of the archive and scripts for executing the test programs. Submissions can be sent by email to [email protected]. Contact this address for further information.

The closing date for submissions is July 1, 2014.

Good luck to you all!

Transition metal dichalcogenides (molybdenum disulfide and tungsten diselenide) rock the graphene boat

Anyone who’s read stories about scientific discovery knows that the early stages are characterized by a number of possibilities so the current race to unseat graphene as the wonder material of the nanoworld is a ‘business as usual’ sign although I imagine it can be confusing for investors and others hoping to make their fortunes. As for the contenders to the ‘wonder nanomaterial throne’, they are transition metal dichalcogenides: molybdenum disulfide and tungsten diselenide both of which have garnered some recent attention.

A March 12, 2014 news item on Nanwerk features research on molybdenum disulfide from Poland,

Will one-atom-thick layers of molybdenum disulfide, a compound that occurs naturally in rocks, prove to be better than graphene for electronic applications? There are many signs that might prove to be the case. But physicists from the Faculty of Physics at the University of Warsaw have shown that the nature of the phenomena occurring in layered materials are still ill-understood and require further research.

….

Researchers at the University of Warsaw, Faculty of Physics (FUW) have shown that the phenomena occurring in the crystal network of molybdenum disulfide sheets are of a slightly different nature than previously thought. A report describing the discovery, achieved in collaboration with Laboratoire National des Champs Magnétiques Intenses in Grenoble, has recently been published in Applied Physics Letters.

“It will not become possible to construct complex electronic systems consisting of individual atomic sheets until we have a sufficiently good understanding of the physics involved in the phenomena occurring within the crystal network of those materials. Our research shows, however, that research still has a long way to go in this field”, says Prof. Adam Babinski at the UW Faculty of Physics.

A March 12, 2014 Dept. of Physics University of Warsaw (FUW) news release, which originated the news item, describes the researchers’ ideas about graphene and alternative materials such as molybdenum disulfide,

“It will not become possible to construct complex electronic systems consisting of individual atomic sheets until we have a sufficiently good understanding of the physics involved in the phenomena occurring within the crystal network of those materials. Our research shows, however, that research still has a long way to go in this field”, says Prof. Adam Babiński at the UW Faculty of Physics.

The simplest method of creating graphene is called exfoliation: a piece of scotch tape is first stuck to a piece of graphite, then peeled off. Among the particles that remain stuck to the tape, one can find microscopic layers of graphene. This is because graphite consists of many graphene sheets adjacent to one another. The carbon atoms within each layer are very strongly bound to one another (by covalent bonds, to which graphene owes its legendary resilience), but the individual layers are held together by significantly weaker bonds (van de Walls [van der Waals] bonds). Ordinary scotch tape is strong enough to break the latter and to tear individual graphene sheets away from the graphite crystal.

A few years ago it was noticed that just as graphene can be obtained from graphite, sheets a single atom thick can similarly be obtained from many other crystals. This has been successfully done, for instance, with transition metals chalcogenides (sulfides, selenides, and tellurides). Layers of molybdenum disulfide (MoS2), in particular, have proven to be a very interesting material. This compound exists in nature as molybdenite, a crystal material found in rocks around the world, frequently taking the characteristic form of silver-colored hexagonal plates. For years molybdenite has been used in the manufacturing of lubricants and metal alloys. Like in the case of graphite, the properties of single-atom sheets of MoS2 long went unnoticed.

From the standpoint of applications in electronics, molybdenum disulfide sheets exhibit a significant advantage over graphene: they have an energy gap, an energy range within which no electron states can exist. By applying electric field, the material can be switched between a state that conducts electricity and one that behaves like an insulator. By current calculations, a switched-off molybdenum disulfide transistor would consume even as little as several hundred thousand times less energy than a silicon transistor. Graphene, on the other hand, has no energy gap and transistors made of graphene cannot be fully switched off.

The news release goes on to describe how the researchers refined their understanding of molybdenum disulfide and its properties,

Valuable information about a crystal’s structure and phenomena occurring within it can be obtained by analyzing how light gets scattered within the material. Photons of a given energy are usually absorbed by the atoms and molecules of the material, then reemitted at the same energy. In the spectrum of the scattered light one can then see a distinctive peak, corresponding to that energy. It turns out, however, that one out of many millions of photons is able to use some of its energy otherwise, for instance to alter the vibration or circulation of a molecule. The reverse situation also sometimes occurs: a photon may take away some of the energy of a molecule, and so its own energy slightly increases. In this situation, known as Raman scattering, two smaller peaks are observed to either side of the main peak.

The scientists at the UW Faculty of Physics analyzed the Raman spectra of molybdenum disulfide carrying on low-temperature microscopic measurements. The higher sensitivity of the equipment and detailed analysis methods enabled the team to propose a more precise model of the phenomena occurring in the crystal network of molybdenum disulfide.

“In the case of single-layer materials, the shape of the Raman lines has previously been explained in terms of phenomena involving certain characteristic vibrations of the crystal network. We have shown for molybdenum disulfide sheets that the effects ascribed to those vibrations must actually, at least in part, be due to other network vibrations not previously taken into account”, explains Katarzyna Gołasa, a doctorate student at the UW Faculty of Physics.

The presence of the new type of vibration in single-sheet materials has an impact on how electrons behave. As a consequence, these materials must have somewhat different electronic properties than previously anticipated.

Here’s what the rocks look like,

Molybdenum disulfide occurs in nature as molybdenite, crystalline material that frequently takes the characteristic form of silver-colored hexagonal plates. (Source: FUW)

Molybdenum disulfide occurs in nature as molybdenite, crystalline material that frequently takes the characteristic form of silver-colored hexagonal plates. (Source: FUW)

I am not able to find the published research at this time (March 13, 2014).

The tungsten diselenide story is specifically application-centric. Dexter Johnson in a March 11, 2014 post on his Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website) describes the differing perspectives and potential applications suggested by the three teams that cooperated to produce papers united by a joint theme ,

The three research groups focused on optoelectronics applications of tungsten diselenide, but each with a slightly different emphasis.

The University of Washington scientists highlighted applications of the material for a light emitting diode (LED). The Vienna University of Technology group focused on the material’s photovoltaic applications. And, finally, the MIT [Massachusetts Institute of Technology] group looked at all of the optoelectronic applications for the material that would result from the way it can be switched from being a p-type to a n-type semiconductor.

Here are some details of the research from each of the institutions’ news releases.

A March 10, 2014 University of Washington (state) news release highlights their LED work,

University of Washington [UW] scientists have built the thinnest-known LED that can be used as a source of light energy in electronics. The LED is based off of two-dimensional, flexible semiconductors, making it possible to stack or use in much smaller and more diverse applications than current technology allows.

“We are able to make the thinnest-possible LEDs, only three atoms thick yet mechanically strong. Such thin and foldable LEDs are critical for future portable and integrated electronic devices,” said Xiaodong Xu, a UW assistant professor in materials science and engineering and in physics.

The UW’s LED is made from flat sheets of the molecular semiconductor known as tungsten diselenide, a member of a group of two-dimensional materials that have been recently identified as the thinnest-known semiconductors. Researchers use regular adhesive tape to extract a single sheet of this material from thick, layered pieces in a method inspired by the 2010 Nobel Prize in Physics awarded to the University of Manchester for isolating one-atom-thick flakes of carbon, called graphene, from a piece of graphite.

In addition to light-emitting applications, this technology could open doors for using light as interconnects to run nano-scale computer chips instead of standard devices that operate off the movement of electrons, or electricity. The latter process creates a lot of heat and wastes power, whereas sending light through a chip to achieve the same purpose would be highly efficient.

“A promising solution is to replace the electrical interconnect with optical ones, which will maintain the high bandwidth but consume less energy,” Xu said. “Our work makes it possible to make highly integrated and energy-efficient devices in areas such as lighting, optical communication and nano lasers.”

Here’s a link to and a citation for this team’s paper,

Electrically tunable excitonic light-emitting diodes based on monolayer WSe2 p–n junctions by Jason S. Ross, Philip Klement, Aaron M. Jones, Nirmal J. Ghimire, Jiaqiang Yan, D. G. Mandrus, Takashi Taniguchi, Kenji Watanabe, Kenji Kitamura, Wang Yao, David H. Cobden, & Xiaodong Xu. Nature Nanotechnology (2014) doi:10.1038/nnano.2014.26 Published online 09 March 2014

This paper is behind a paywall.

A March 9, 2014 University of Vienna news release highlights their work on tungsten diselinide and its possible application in solar cells,

… With graphene as a light detector, optical signals can be transformed into electric pulses on extremely short timescales.

For one very similar application, however, graphene is not well suited for building solar cells. “The electronic states in graphene are not very practical for creating photovoltaics”, says Thomas Mueller. Therefore, he and his team started to look for other materials, which, similarly to graphene, can arranged in ultrathin layers, but have even better electronic properties.

The material of choice was tungsten diselenide: It consists of one layer of tungsten atoms, which are connected by selenium atoms above and below the tungsten plane. The material absorbs light, much like graphene, but in tungsten diselenide, this light can be used to create electrical power.

The layer is so thin that 95% of the light just passes through – but a tenth of the remaining five percent, which are absorbed by the material, are converted into electrical power. Therefore, the internal efficiency is quite high. A larger portion of the incident light can be used if several of the ultrathin layers are stacked on top of each other – but sometimes the high transparency can be a useful side effect. “We are envisioning solar cell layers on glass facades, which let part of the light into the building while at the same time creating electricity”, says Thomas Mueller.

Today, standard solar cells are mostly made of silicon, they are rather bulky and inflexible. Organic materials are also used for opto-electronic applications, but they age rather quickly. “A big advantage of two-dimensional structures of single atomic layers is their crystallinity. Crystal structures lend stability”, says Thomas Mueller.

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

Solar-energy conversion and light emission in an atomic monolayer p–n diode by Andreas Pospischil, Marco M. Furchi, & Thomas Mueller. Nature Nanotechnology (2014) doi:10.1038/nnano.2014.14 Published online 09 March 2014

This paper is behind a paywll.

Finally, a March 10, 2014 MIT news release details their work about material able to switch from p-type (p = positive) to a n-type (n = negative) semiconductors,

The material they used, called tungsten diselenide (WSe2), is part of a class of single-molecule-thick materials under investigation for possible use in new optoelectronic devices — ones that can manipulate the interactions of light and electricity. In these experiments, the MIT researchers were able to use the material to produce diodes, the basic building block of modern electronics.

Typically, diodes (which allow electrons to flow in only one direction) are made by “doping,” which is a process of injecting other atoms into the crystal structure of a host material. By using different materials for this irreversible process, it is possible to make either of the two basic kinds of semiconducting materials, p-type or n-type.

But with the new material, either p-type or n-type functions can be obtained just by bringing the vanishingly thin film into very close proximity with an adjacent metal electrode, and tuning the voltage in this electrode from positive to negative. That means the material can easily and instantly be switched from one type to the other, which is rarely the case with conventional semiconductors.

In their experiments, the MIT team produced a device with a sheet of WSe2 material that was electrically doped half n-type and half p-type, creating a working diode that has properties “very close to the ideal,” Jarillo-Herrero says.

By making diodes, it is possible to produce all three basic optoelectronic devices — photodetectors, photovoltaic cells, and LEDs; the MIT team has demonstrated all three, Jarillo-Herrero says. While these are proof-of-concept devices, and not designed for scaling up, the successful demonstration could point the way toward a wide range of potential uses, he says.

“It’s known how to make very large-area materials” of this type, Churchill says. While further work will be required, he says, “there’s no reason you wouldn’t be able to do it on an industrial scale.”

In principle, Jarillo-Herrero says, because this material can be engineered to produce different values of a key property called bandgap, it should be possible to make LEDs that produce any color — something that is difficult to do with conventional materials. And because the material is so thin, transparent, and lightweight, devices such as solar cells or displays could potentially be built into building or vehicle windows, or even incorporated into clothing, he says.

While selenium is not as abundant as silicon or other promising materials for electronics, the thinness of these sheets is a big advantage, Churchill points out: “It’s thousands or tens of thousands of times thinner” than conventional diode materials, “so you’d use thousands of times less material” to make devices of a given size.

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

Optoelectronic devices based on electrically tunable p–n diodes in a monolayer dichalcogenide by Britton W. H. Baugher, Hugh O. H. Churchill, Yafang Yang, & Pablo Jarillo-Herrero. Nature Nanotechnology (2014) doi:10.1038/nnano.2014.25 Published online 09 March 2014

This paper is behind a paywall.

These are very exciting, if not to say, electrifying times. (Couldn’t resist the wordplay.)

Tracking gas, oil, and, possibly, water in wells

A Feb. 24, 2014 Rice University news release (also on EurekAlert) and on Azonano as a Feb. 25, 2014 news item) describes a technique tracks which wells are producing oil or gas in fracking operations,

A tabletop device invented at Rice University can tell how efficiently a nanoparticle would travel through a well and may provide a wealth of information for oil and gas producers.

The device gathers data on how tracers – microscopic particles that can be pumped into and recovered from wells – move through deep rock formations that have been opened by hydraulic fracturing [fracking].

Here’s an image of two Rice scientists playing around with a prototype of their tabletop device,

Rice University chemist Andrew Barron and graduate student Brittany Oliva-Chatelain investigate the prototype of a device that allows for rapid testing of nanotracers for the evaluation of wells subject to hydraulic fracturing. (Credit: Jeff Fitlow/Rice University)

Rice University chemist Andrew Barron and graduate student Brittany Oliva-Chatelain investigate the prototype of a device that allows for rapid testing of nanotracers for the evaluation of wells subject to hydraulic fracturing. (Credit: Jeff Fitlow/Rice University)

The news release goes on to describe the fracking process and explain why the companies don’t know which well is actually producing (Note: Links have been removed),

Drilling companies use fracturing to pump oil and gas from previously unreachable reservoirs. Fluids are pumped into a wellbore under high pressure to fracture rocks, and materials called “proppants,” like sand or ceramic, hold the fractures open. “They’re basically making a crack in the rock and filling it with little beads,” said Rice chemist Andrew Barron, whose lab produced the device detailed in the Royal Society of Chemistry journal Environmental Science Processes and Impacts.

But the companies struggle to know which insertion wells — where fluids are pumped in — are connected to the production wells where oil and gas are pumped out. “They may be pumping down three wells and producing from six, but they have very little idea of which well is connected to which,” he said.

Tracer or sensor particles added to fracturing fluids help solve that problem, but there’s plenty of room for optimization, especially in minimizing the volume of nanoparticles used now, he said. “Ideally, we would take a very small amount of a particle that does not interact with proppant, rock or the gunk that’s been pumped downhole, inject it in one well and collect it at the production well. The time it takes to go from one to the other will tell you about the connectivity underground.”

Barron explained the proppant itself accounts for most of the surface area the nanoparticles encounter, so it’s important to tune the tracers to the type of proppant used.

He said the industry lacks a uniform method to test and optimize custom-designed nanoparticles for particular formations and fluids. The ultimate goal  is to optimize the particles so they don’t clump together or stick to the rock or proppant and can be reliably identified when they exit the production well.

Here’s how the tracers work (from the news release),

The automated device by Barron, Rice alumnus Samuel Maguire-Boyle and their colleagues allows them to run nanotracers through a small model of a geological formation and quickly analyze what comes out the other side.

The device sends a tiny amount of silver nanoparticle tracers in rapid pulses through a solid column, simulating the much longer path the particles would travel in a well. That gives the researchers an accurate look at both how sticky and how robust the particles are.

“We chose silver nanoparticles for their plasmon resonance,” Barron said. “They’re very easy to see (with a spectroscope) making for high-quality data.” He said silver nanoparticles would be impractical in a real well, but because they’re easy to modify with other useful chemicals, they are good models for custom nanoparticles.

“The process is simple enough that our undergraduates make different nanoparticles and very quickly test them to find out how they behave,” Barron said.

The method also shows promise for tracking water from source to destination, which could be valuable for government agencies that want to understand how aquifers are linked or want to trace the flow of elements like pollutants in a water supply, he said.

Barron said the Rice lab won’t oversee production of the test rig, but it doesn’t have to. “We just published the paper, but if companies want to make their own, it includes the instructions. The supplementary material is basically a manual for how to do this,” he said.

You can find the paper with this link and/or citation,

Automated method for determining the flow of surface functionalized nanoparticles through a hydraulically fractured mineral formation using plasmonic silver nanoparticles by Samuel J. Maguire-Boyle, David J. Garner, Jessica E. Heimann, Lucy Gao, Alvin W. Orbaek, and Andrew R. Barron. Environ. Sci.: Processes Impacts, 2014,16, 220-231 DOI: 10.1039/C3EM00718A First published online 07 Jan 2014

This paper has been published in one of the Royal Society’s open access journals.

My final note, one of my more recent posts about fracking highlights some research that was taking place in Texas (Rice University’s home state) at Texas A&M University, see my July 29, 2013 posting.