Cookies, ants, and a citizen science project plus a call for proposals for a 2015 Citizen Science Conference

My first citizen science item concerns summertime when the ants are out and about, oftentimes as uninvited participants to a picnic. Scientists at North Carolina State University (NCSU) and the University of Florida (UF) have decided to take advantage of this summer phenomenon as per a July 7, 2014 news item on ScienceDaily,

Scientists from North Carolina State University and the University of Florida have combined cookies, citizen science and robust research methods to track the diversity of ant species across the United States, and are now collaborating with international partners to get a global perspective on how ants are moving and surviving in the modern world.

“We think our School of Ants project serves as a good model for how citizen science can be used to collect more data, more quickly, from more places than a research team could do otherwise,” says Dr. Andrea Lucky, a researcher at the University of Florida who started work on the School of Ants while a postdoctoral researcher at NC State and now heads the project. Lucky is co-lead author of a paper describing the work and its early findings. “And our protocols help ensure that the data we are collecting are high quality.”

A July 7, 2014 NCSU news release (also on EurekAlert), which originated the news item, describes the various objectives for the project,

The School of Ants project was developed at NC State to help researchers get a handle on the diversity of ant species across the United States, with a particular focus on Chicago, Raleigh and New York City. In short, to discover which ant species are living where.

“But we also wanted to launch a citizen science project that both increased the public’s ecological literacy and addressed criticisms that public involvement made citizen science data unreliable,” says Dr. Amy Savage , a postdoctoral biological sciences researcher at NC State and the other co-lead author of the paper.

The research protocol, process, and outcomes are then described (from the news release),

The researchers developed a simple protocol involving Pecan Sandies cookies and sealable plastic bags, detailing precisely how the public should collect and label ant samples before shipping them to NC State or UF. [emphasis mine] This process was designed to engage the public in the aspect of the research that was easiest for non-scientists to enjoy and participate in, while also limiting the chances that the public could make mistakes that would skew the findings.

Once the samples arrive at NC State or UF, they are sorted, identified by a team of national experts and entered into a database. That information is then made publicly available in a user-friendly format on the project’s schoolofants.org site, allowing study participants to track the survey.

“This information is helping us tackle a variety of ecological and evolutionary questions, such as how ants may be evolving in urban environments, and how invasive species are spreading in the U.S.,” Savage says.

More than 1,000 participants, with samples from all 50 states, have taken part in the project since its 2011 launch – and there have already been some surprising findings.

For example, the researchers learned that a venomous invasive species, the Asian needle ant (Pachycondyla chinensis), had spread thousands of miles farther than anyone expected. Researchers knew the species had established itself in the Southeast, but study participants sent in Asian needle ant samples from as far afield as Wisconsin and Washington state.

To build on the School of Ants model, the researchers have launched collaborations with counterparts in Italy and Australia.

“We’re optimistic that this project will give us a broader view of ant diversity and how these species intersect with us, where we live and work around the world,” Lucky says.

The researchers are also working with teachers to incorporate the project into K-12 instruction modules that incorporate key elements of common core education standards. One early teacher collaboration has led to a research paper co-written by 4th and 5th graders.

“We also collaborated with a science writer to produce a free series of iBooks featuring natural history stories about the most common ants that our citizen science partners are collecting in their backyards and sidewalks,” Savage says.

“One of our big goals now is to move from collecting data and finding patterns to identifying ways that we can work with the public to figure out what is driving those patterns,” says Dr. Rob Dunn, an associate professor of biological sciences at NC State and co-author of the paper.

Not being familiar with Pecan Sandies cookies I went searching on the internet and found many recipes including this one from Martha Stewart’s website,

 Pecan Sandies

prep: 15 mins
total time: 30 mins
yield: Makes 18

Ingredients

1/2 cup (1 stick) unsalted butter, room temperature
1/2 cup packed light-brown sugar
1 1/2 teaspoons pure vanilla extract
1/4 teaspoon salt
1 cup all-purpose flour (spooned and leveled)
1 cup pecans, coarsely chopped

Cook’s Note
For best results, line cookie sheets with parchment prior to baking.
Directions

Step 1

Preheat oven to 350 degrees, with racks in upper and lower thirds. In a large bowl, using an electric mixer, beat butter and sugar until light and fluffy; beat in vanilla and salt. With mixer on low, gradually add flour, beating just until combined. Fold in pecans.

Step 2

Roll dough into 1 1/2-inch balls, and place on two baking sheets, 2 inches apart. With the dampened bottom of a glass, lightly flatten each ball.

Step 3

Bake until cookies are golden brown, 15 to 17 minutes, rotating sheets halfway through. Transfer to wire racks, and let cool.

This is what they look like (also from the Martha Stewart website),

[downloaded from http://www.marthastewart.com/342386/pecan-sandies]

[downloaded from http://www.marthastewart.com/342386/pecan-sandies]

I also checked out the School of Ants project website and found this,

The School of Ants project is a citizen-scientist driven study of the ants that live in urban areas, particularly around homes and schools. Participation is open to anyone interested!
Learn More!

Anyone can participate! Learn how to create your own sampling kit, sample your backyard or schoolyard, and get our collection back to us so that we can ID the ants and add your species list to the big School of Ants map. Together we’ll map ant diversity and species ranges across North America! Click here to get started!

There is at least one question you might want to ask before running off to collect ants, the researchers specify Keebler Pecan Sandies cookies are to be used as bait. I’m not sure how available those specific cookies and brand are in Canada, Mexico, Italy, or Australia. You may want to check with the organizers as to what alternatives might be acceptable. From the Participate webpage on the School of Ants website,

SAMPLING ANTS for the School of Ants involves placing cookie baits outdoors in green spaces (lawns, gardens, woods) and paved places (asphalt, concrete, cobblestone) for one hour on a warm day. We want to know what ants discover the baits in your neighborhood!(ALLERGY WARNING!: this activity uses Keebler Pecan Sandies cookies, which contain pecans, wheat, egg and whey).

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

Ecologists, educators, and writers collaborate with the public to assess backyard diversity in The School of Ants Project [PDF] by Andrea Lucky, Amy M. Savage, Lauren M. Nichols, Leonora Shell, Robert R. Dunn, Cristina Castracani, Donato A. Grasso, and Alessandra Mori. Ecosphere 5(7):78. http://dx.doi.org/10.1890/ES13-00364.1 Published: online July 7, 2014,

Ecosphere is an open access journal. The PDF is 23 pp.

For my second citizen science item, I have a call for proposals for the Citizen Science 2015 Conference (CS2015), February 11 & 12, 2015 in San Jose, California (prior to the 2015 AAAS [American Association for the Advancement of Science] annual meeting February 12 -16, 2015 also in San Jose). Here’s more about the Citizen Science conference from the Overview page,

Anyone involved in citizen science is invited to attend this conference. Attendees will include citizen science participants, researchers, project leaders, educators, technology specialists, evaluators, and others – representing many disciplines including astronomy, molecular biology, human and environmental health, psychology, linguistics, environmental justice, biodiversity, conservation biology, public health, genetics, engineering, cyber technology, gaming, and more – at any level of expertise. There will be opportunities throughout the conference to make connections, share insights, and help move this field forward.

We have identified six main themes for this year’s conference:

  1. Tackling Grand Challenges and Everyday Problems with Citizen Science
  2. Broadening Engagement to Foster Diversity and Inclusion
  3. Making Education and Lifelong Learning Connections (K-12, university, informal)
  4. Digital Opportunities and Challenges in Citizen Science
  5. Research on and Evaluation of the Citizen Science Experience
  6. Best Practices for Designing, Implementing, and Managing Citizen Science Projects and Programs

Here are important dates for the conference (from a June 30, 2014 email announcement),

September 15, 2014          CS2015 Deadline to submit proposals* (talks, posters, etc)
October 6, 2014                 CS2015 Proposal selection notices sent out
November 10, 2014           CS2015 Early-bird registration discount ends
February 11 & 12, 2015     CS2015 Conference

Here’s more detail, from the Presentation Styles webpage,

… Several formats are available to choose from: three styles of oral presentations; symposia/panel discussions; and posters.

Audio-visual equipment will be provided as needed for all session types except posters.

Oral Presentations
Talks allow speakers to present their work in 12 minutes, with 3 additional minutes for audience questions. Talks with similar themes will be grouped together into sessions.

Speed Talks, as the name suggests, challenge each presenter to cover his or her topic in 5 minutes or less. Following a series of speed presentations, there will be time for audience members to gather with presenters for discussion.

Story Presentations (15 minutes) emphasize sharing valuable lessons through storytelling. We especially encourage telling stories of “what didn’t work and why” and strategies for addressing challenges and unintended consequences.

Symposium Sessions or Panel Discussions (1 to 2 hours)
Every symposium or panel has one convener (most likely the person submitting this proposal); that person is responsible for organizing the session and will act as the session’s contact person with conference organizers. Additionally, that person will moderate/guide the session. Symposia/Panels may be 1-to-2 hours in length, depending on the number of proposed talks, and must include at least 15 minutes for questions and discussion with the audience.

The proposal must (1) describe the symposium or panel’s objective, (2) how it will contribute to the overall theme of the conference, and (3) include a list of proposed speakers (and, in the case of a symposium, each speaker’s topic).

Posters
Posters are designed to visually display information and engage fellow attendees in an informal way. There will be two Poster Sessions—one each day—inviting attendees to discuss posters with authors. Posters will also be on display outside of formal poster-session times. All accepted posters will be given a display space measuring 4 x 4 feet (1.2 X 1.2 meters) in the Poster Hall (no additional audio-visual aids are permitted).

You can access a link to submit your proposal here.

CS2015 is being called a pre-conference to the AAAS meeting as per the Prepare for the Conference page,

Registration
Registration details, including the conference registration fee, are not yet finalized. We are seeking funding to help support the conference and keep it affordable to all. Check back for updates, or join the CSA to receive periodic updates.

Attend Two Great Conferences
CS2015 is a pre-conference of the Annual Meeting of the American Association for the Advancement of Science (AAAS), which immediately follows our meeting at the San Jose Convention Center. The AAAS theme for 2015 is “Innovations, Information, and Imaging.” Once you have completed your CS2015 registration, you will receive instructions on how to register for the AAAS Annual Meeting (February 12-16, 2015) at the discounted rate of $235. AAAS registration will open in August 2014.

Good luck with your proposal and with your ant-captures!

Carbyne stretches from theory to reality and reveals its conundrum-type self

Rice University (Texas, US) scientists have taken a rather difficult material, carbyne, and twisted it to reveal new properties according to a July 21, 2014 news item on ScienceDaily,

Applying just the right amount of tension to a chain of carbon atoms can turn it from a metallic conductor to an insulator, according to Rice University scientists.

Stretching the material known as carbyne — a hard-to-make, one-dimensional chain of carbon atoms — by just 3 percent can begin to change its properties in ways that engineers might find useful for mechanically activated nanoscale electronics and optics.

A July 21, 2014 Rice University news release (also on EurekAlert), which originated the news item, describes carbyne and some of the difficulties the scientists addressed in their research on the material,

Until recently, carbyne has existed mostly in theory, though experimentalists have made some headway in creating small samples of the finicky material. The carbon chain would theoretically be the strongest material ever, if only someone could make it reliably.

The first-principle calculations by Yakobson and his co-authors, Rice postdoctoral researcher Vasilii Artyukhov and graduate student Mingjie Liu, show that stretching carbon chains activates the transition from conductor to insulator by widening the material’s band gap. Band gaps, which free electrons must overcome to complete a circuit, give materials the semiconducting properties that make modern electronics possible.

In their previous work on carbyne, the researchers believed they saw hints of the transition, but they had to dig deeper to find that stretching would effectively turn the material into a switch.

Each carbon atom has four electrons available to form covalent bonds. In their relaxed state, the atoms in a carbyne chain would be more or less evenly spaced, with two bonds between them. But the atoms are never static, due to natural quantum uncertainty, which Yakobson said keeps them from slipping into a less-stable Peierls distortion.

“Peierls said one-dimensional metals are unstable and must become semiconductors or insulators,” Yakobson said. “But it’s not that simple, because there are two driving factors.”

One, the Peierls distortion, “wants to open the gap that makes it a semiconductor.” The other, called zero-point vibration (ZPV), “wants to maintain uniformity and the metal state.”

Yakobson explained that ZPV is a manifestation of quantum uncertainty, which says atoms are always in motion. “It’s more a blur than a vibration,” he said. “We can say carbyne represents the uncertainty principle in action, because when it’s relaxed, the bonds are constantly confused between 2-2 and 1-3, to the point where they average out and the chain remains metallic.”

But stretching the chain shifts the balance toward alternating long and short (1-3) bonds. That progressively opens a band gap beginning at about 3 percent tension, according to the computations. The Rice team created a phase diagram to illustrate the relationship of the band gap to strain and temperature.

How carbyne is attached to electrodes also matters, Artyukhov said. “Different bond connectivity patterns can affect the metallic/dielectric state balance and shift the transition point, potentially to where it may not be accessible anymore,” he said. “So one has to be extremely careful about making the contacts.”

“Carbyne’s structure is a conundrum,” he said. “Until this paper, everybody was convinced it was single-triple, with a long bond then a short bond, caused by Peierls instability.” He said the realization that quantum vibrations may quench Peierls, together with the team’s earlier finding that tension can increase the band gap and make carbyne more insulating, prompted the new study.

“Other researchers considered the role of ZPV in Peierls-active systems, even carbyne itself, before we did,” Artyukhov said. “However, in all previous studies only two possible answers were being considered: either ‘carbyne is semiconducting’ or ‘carbyne is metallic,’ and the conclusion, whichever one, was viewed as sort of a timeless mathematical truth, a static ‘ultimate verdict.’ What we realized here is that you can use tension to dynamically go from one regime to the other, which makes it useful on a completely different level.”

Yakobson noted the findings should encourage more research into the formation of stable carbyne chains and may apply equally to other one-dimensional chains subject to Peierls distortions, including conducting polymers and charge/spin density-wave materials.

According to the news release the research was funded by the U.S. Air Force Office of Scientific Research, the Office of Naval Research Multidisciplinary University Research Initiative, and the Robert Welch Foundation. (I can’t recall another instance of the air force and the navy funding the same research.) In any event, here’s a link to and a citation for the paper,

Mechanically Induced Metal–Insulator Transition in Carbyne by Vasilii I. Artyukhov, Mingjie Liu, and Boris I. Yakobson. Nano Lett., Article ASAP DOI: 10.1021/nl5017317 Publication Date (Web): July 3, 2014

Copyright © 2014 American Chemical Society

This paper is behind a paywall.

The researchers have provided an image to illustrate their work,

[downloaded from http://pubs.acs.org/doi/abs/10.1021/nl5017317]

[downloaded from http://pubs.acs.org/doi/abs/10.1021/nl5017317]

I’m not sure what the bird is doing in the image but it caught my fancy. There is another less whimsical illustration (you can see it in the  July 21, 2014 news item on ScienceDaily) and I believe the same caption can be used for the one I’ve chosen from the journal’s abstract page, “Carbyne chains of carbon atoms can be either metallic or semiconducting, according to first-principle calculations by scientists at Rice University. Stretching the chain dimerizes the atoms, opening a band gap between the pairs. Credit: Vasilii Artyukhov/Rice University.”

I last wrote about carbyne in an Oct. 9, 2013 posting where I noted that the material was unlikely to dethrone graphene as it didn’t appear to have properties useful in electronic applications. It seems the scientists have proved otherwise, at least in the laboratory.

Transmetalation, substituting one set of metal atoms for another set

Transmetalation bears a resemblance of sorts to transmutation. While the chemists from the University of Oregon aren’t turning lead to gold through an alchemical process they are switching out individual metal atoms, aluminum for indium. From a July 21, 2014 news item on ScienceDaily,

The yield so far is small, but chemists at the University of Oregon have developed a low-energy, solution-based mineral substitution process to make a precursor to transparent thin films that could find use in electronics and alternative energy devices.

A paper describing the approach is highlighted on the cover of the July 21 [2014] issue of the journal Inorganic Chemistry, which draws the most citations of research in the inorganic and nuclear chemistry fields. [emphasis mine] The paper was chosen by the American Chemical Society journal as an ACS Editor’s Choice for its potential scientific and broad public interest when it initially published online.

One observation unrelated to the research, the competition amongst universities seems to be heating up. While journals often tout their impact factor, it’s usually more discreetly than in what amounts to a citation in the second paragraph of the university news release, which originated the news item.

The July 21, 2014 University of Oregon news release (also on EurekAlert), describes the work in more detail,

The process described in the paper represents a new approach to transmetalation, in which individual atoms of one metal complex — a cluster in this case — are individually substituted in water. For this study, Maisha K. Kamunde-Devonish and Milton N. Jackson Jr., doctoral students in the Department of Chemistry and Biochemistry, replaced aluminum atoms with indium atoms.

The goal is to develop inorganic clusters as precursors that result in dense thin films with negligible defects, resulting in new functional materials and thin-film metal oxides. The latter would have wide application in a variety of electronic devices.

“Since the numbers of compounds that fit this bill is small, we are looking at transmetelation as a method for creating new precursors with new combinations of metals that would circumvent barriers to performance,” Kamunde-Devonish said.

Components in these devices now use deposition techniques that require a lot of energy in the form of pressure or temperature. Doing so in a more green way — reducing chemical waste during preparation — could reduce manufacturing costs and allow for larger-scale materials, she said.

“In essence,” said co-author Darren W. Johnson, a professor of chemistry, “we can prepare one type of nanoscale cluster compound, and then step-by-step substitute out the individual metal atoms to make new clusters that cannot be made by direct methods. The cluster we report in this paper serves as an excellent solution precursor to make very smooth thin films of amorphous aluminum indium oxide, a semiconductor material that can be used in transparent thin-film transistors.”

Transmetalation normally involves a reaction done in organic chemistry in which the substitution of metal ions generates new metal-carbon bonds for use in catalytic systems and to synthesize new metal complexes.

“This is a new way to use the process,” Kamunde-Devonish said, “Usually you take smaller building blocks and put them together to form a mix of your basic two or three metals. Instead of building a house from the ground up, we’re doing some remodeling. In everyday life that happens regularly, but in chemistry it doesn’t happen very often. We’ve been trying to make materials, compounds, anything that can be useful to improve the processes to make thin films that find application in a variety of electronic devices.”

The process, she added, could be turned into a toolbox that allows for precise substitutions to generate specifically desired properties. “Currently, we can only make small amounts,” she said, “but the fact that we can do this will allow us to get a fundamental understanding of how this process happens. The technology is possible already. It’s just a matter of determining if this type of material we’ve produced is the best for the process.”

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

Transmetalation of Aqueous Inorganic Clusters: A Useful Route to the Synthesis of Heterometallic Aluminum and Indium Hydroxo—Aquo Clusters by Maisha K. Kamunde-Devonish, Milton N. Jackson, Jr., Zachary L. Mensinger, Lev N. Zakharov, and Darren W. Johnson. Inorg. Chem., 2014, 53 (14), pp 7101–7105 DOI: 10.1021/ic403121r Publication Date (Web): April 18, 2014

Copyright © 2014 American Chemical Society

This paper appears to be open access (I was able to view the HTML version when I clicked).

Live webcast about data journalism on July 30, 2014 and a webinar featuring the 2014 NNI (US National Nanotechnology Initiative) EHS (Environment, Health and Safety) Progress Review on July 31, 2014

The Woodrow Wilson International Center for Scholars is hosting a live webcast on data journalism scheduled for July 30, 2014. For those us who are a little fuzzy as to what the term ‘data journalism’ means, this is probably a good opportunity to find out as per the description in the Wilson Center’s July 23, 2014 email announcement,

What is data journalism? Why does it matter? How has the maturing field of data science changed the direction of journalism and global investigative reporting? Our speakers will discuss the implications for policymakers and institutional accountability, and how the balance of power in information gathering is shifting worldwide, with implications for decision-making and open government.

This event will be live webcast and you may follow it on twitter @STIPcommonslab and #DataJournalism

Wednesday, July 30th, 2014
10am – 12pm EST
5th Floor Conference Room
[Woodrow Wilson International Center for Scholars
Ronald Reagan Building and International Trade Center
One Woodrow Wilson Plaza - 1300 Pennsylvania Ave., NW, Washington, DC 20004-3027
T 1-202-691-4000]

Speakers:

Alexander B. Howard
Writer and Editor, TechRepublic and founder of the blog “E Pluribus Unum.” Previously, he was a fellow at the Tow Center for Digital Journalism at Columbia University, the Ash Center at Harvard University and the Washington Correspondent for O’Reilly Media.

Kalev H. Leetaru
Yahoo! Fellow at Georgetown University, a Council Member of the World Economic Forum’s Global Agenda Council on the Future of Government, and a Foreign Policy Magazine Top 100 Global Thinker of 2013. For nearly 20 years he has been studying the web and building systems to interact with and understand the way it is reshaping our global society.

Louise Lief (Moderator)
Public Policy Scholar at the Wilson Center. Her project, “Science and the Media” explores innovative ways to make environmental science more accessible and useful to all journalists. She is investigating how new technologies and civic innovation tools can benefit both the media and science.

I believe you need to RSVP if you are attending in person but it’s not necessary for the livestream.

The other announcement comes via a July 23, 2014 news item on Nanowerk,

The National Nanotechnology Coordination Office (NNCO) will hold a public webinar on Thursday, July 31, 2014, to provide a forum to answer questions related to the “Progress Review on the Coordinated Implementation of the National Nanotechnology Initiative (NNI) 2011 Environmental, Health, and Safety Research Strategy.”

The full notice can be found on the US nano.gov website,

When: The webinar will be live on Thursday, July 31, 2014 from 12:00 pm-1 pm.
Where: Click here to register for the online webcast

While it’s open to the public, I suspect this is an event designed largely for highly interested parties such as the agencies involved in EHS activities, nongovernmental organizations that act as watchdogs, and various government policy wonks. Here’s how they describe their proposed discussions (from the event notice page),

Discussion during the webinar will focus on the research activities undertaken by NNI agencies to advance the current state of the science as highlighted in the Progress Review. Representative research activities as provided in the Progress Review will be discussed in the context of the 2011 NNI EHS Research Strategy’s six core research areas: Nanomaterial Measurement Infrastructure, Human Exposure Assessment, Human Health, the Environment, Risk Assessment and Risk Management Methods, and Informatics and Modeling.

How: During the question-and-answer segment of the webinar, submitted questions will be considered in the order received. A moderator will identify relevant questions and pose them to the panel of NNI agency representatives. Due to time constraints, not all questions may be addressed.  The moderator reserves the right to group similar questions and to skip questions, as appropriate. The NNCO will begin accepting questions and comments via email ([email protected]) at 1 pm on Thursday, July 24th (EDT) until the close of the webinar at 1 pm (EDT) on July 31st.

The Panelists:  The panelists for the webinar are subject matter experts from the Federal Government.

Additional Information: A public copy of the “Progress Review on the Coordinated Implementation of the National Nanotechnology Initiative 2011 Environmental, Health, and Safety Research Strategy” can be accessed at www.nano.gov/2014EHSProgressReview. The 2011 NNI EHS Research Strategy can be accessed at www.nano.gov/node/681.
- See more at: http://www.nano.gov/node/1166#sthash.Ipr0bFeP.dpuf

Gold on the brain, a possible nanoparticle delivery system for drugs

A July 21, 2014 news item on Nanowerk describes special gold nanoparticles that could make drug delivery to cells easier,

A special class of tiny gold particles can easily slip through cell membranes, making them good candidates to deliver drugs directly to target cells.

A new study from MIT materials scientists reveals that these nanoparticles enter cells by taking advantage of a route normally used in vesicle-vesicle fusion, a crucial process that allows signal transmission between neurons.

A July 21, 2014 MIT (Massachusetts Institute of Technology) news release (also on EurekAlert), which originated the news item, provides more details,

The findings suggest possible strategies for designing nanoparticles — made from gold or other materials — that could get into cells even more easily.

“We’ve identified a type of mechanism that might be more prevalent than is currently known,” says Reid Van Lehn, an MIT graduate student in materials science and engineering and one of the paper’s lead authors. “By identifying this pathway for the first time it also suggests not only how to engineer this particular class of nanoparticles, but that this pathway might be active in other systems as well.”

The paper’s other lead author is Maria Ricci of École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland. The research team, led by Alfredo Alexander-Katz, an associate professor of materials science and engineering, and Francesco Stellacci from EPFL, also included scientists from the Carlos Besta Institute of Neurology in Italy and Durham University in the United Kingdom.

Most nanoparticles enter cells through endocytosis, a process that traps the particles in intracellular compartments, which can damage the cell membrane and cause cell contents to leak out. However, in 2008, Stellacci, who was then at MIT, and Darrell Irvine, a professor of materials science and engineering and of biological engineering, found that a special class of gold nanoparticles coated with a mix of molecules could enter cells without any disruption.

“Why this was happening, or how this was happening, was a complete mystery,” Van Lehn says.

Last year, Alexander-Katz, Van Lehn, Stellacci, and others discovered that the particles were somehow fusing with cell membranes and being absorbed into the cells. In their new study, they created detailed atomistic simulations to model how this happens, and performed experiments that confirmed the model’s predictions.

Gold nanoparticles used for drug delivery are usually coated with a thin layer of molecules that help tune their chemical properties. Some of these molecules, or ligands, are negatively charged and hydrophilic, while the rest are hydrophobic. The researchers found that the particles’ ability to enter cells depends on interactions between hydrophobic ligands and lipids found in the cell membrane.

Cell membranes consist of a double layer of phospholipid molecules, which have hydrophobic lipid tails and hydrophilic heads. The lipid tails face in toward each other, while the hydrophilic heads face out.

In their computer simulations, the researchers first created what they call a “perfect bilayer,” in which all of the lipid tails stay in place within the membrane. Under these conditions, the researchers found that the gold nanoparticles could not fuse with the cell membrane.

However, if the model membrane includes a “defect” — an opening through which lipid tails can slip out — nanoparticles begin to enter the membrane. When these lipid protrusions occur, the lipids and particles cling to each other because they are both hydrophobic, and the particles are engulfed by the membrane without damaging it.

In real cell membranes, these protrusions occur randomly, especially near sites where proteins are embedded in the membrane. They also occur more often in curved sections of membrane, because it’s harder for the hydrophilic heads to fully cover a curved area than a flat one, leaving gaps for the lipid tails to protrude.

“It’s a packing problem,” Alexander-Katz says. “There’s open space where tails can come out, and there will be water contact. It just makes it 100 times more probable to have one of these protrusions come out in highly curved regions of the membrane.”

This phenomenon appears to mimic a process that occurs naturally in cells — the fusion of vesicles with the cell membrane. Vesicles are small spheres of membrane-like material that carry cargo such as neurotransmitters or hormones.

The similarity between absorption of vesicles and nanoparticle entry suggests that cells where a lot of vesicle fusion naturally occurs could be good targets for drug delivery by gold nanoparticles. The researchers plan to further analyze how the composition of the membranes and the proteins embedded in them influence the absorption process in different cell types. “We want to really understand all the constraints and determine how we can best design nanoparticles to target particular cell types, or regions of a cell,” Van Lehn says.

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

Lipid tail protrusions mediate the insertion of nanoparticles into model cell membranes by Reid C. Van Lehn, Maria Ricci, Paulo H.J. Silva, Patrizia Andreozzi, Javier Reguera, Kislon Voïtchovsky, Francesco Stellacci, & Alfredo Alexander-Katz. Nature Communications 5, Article number: 4482 doi:10.1038/ncomms5482 Published 21 July 2014

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

I last featured this multi-country team’s work on gold nanoparticles in an Aug. 23, 2013 posting.

Steampower via nanotechnology

It seems that researchers at MIT (Massachusetts Institute of Technology (US) have been inspired by steam punk, of a sort. From a July 21, 2014 news item on Nanowerk,

A new material structure developed at MIT generates steam by soaking up the sun.

The structure — a layer of graphite flakes and an underlying carbon foam — is a porous, insulating material structure that floats on water. When sunlight hits the structure’s surface, it creates a hotspot in the graphite, drawing water up through the material’s pores, where it evaporates as steam. The brighter the light, the more steam is generated.

The new material is able to convert 85 percent of incoming solar energy into steam — a significant improvement over recent approaches to solar-powered steam generation. What’s more, the setup loses very little heat in the process, and can produce steam at relatively low solar intensity. This would mean that, if scaled up, the setup would likely not require complex, costly systems to highly concentrate sunlight.

A July 21, 2014 MIT news release, which originated the news item, details the research,

Hadi Ghasemi, a postdoc in MIT’s Department of Mechanical Engineering, says the spongelike structure can be made from relatively inexpensive materials — a particular advantage for a variety of compact, steam-powered applications.

“Steam is important for desalination, hygiene systems, and sterilization,” says Ghasemi, who led the development of the structure. “Especially in remote areas where the sun is the only source of energy, if you can generate steam with solar energy, it would be very useful.”

Today, solar-powered steam generation involves vast fields of mirrors or lenses that concentrate incoming sunlight, heating large volumes of liquid to high enough temperatures to produce steam. However, these complex systems can experience significant heat loss, leading to inefficient steam generation.

Recently, scientists have explored ways to improve the efficiency of solar-thermal harvesting by developing new solar receivers and by working with nanofluids. The latter approach involves mixing water with nanoparticles that heat up quickly when exposed to sunlight, vaporizing the surrounding water molecules as steam. But initiating this reaction requires very intense solar energy — about 1,000 times that of an average sunny day.

By contrast, the MIT approach generates steam at a solar intensity about 10 times that of a sunny day — the lowest optical concentration reported thus far. The implication, the researchers say, is that steam-generating applications can function with lower sunlight concentration and less-expensive tracking systems.

“This is a huge advantage in cost-reduction,” Ghasemi says. “That’s exciting for us because we’ve come up with a new approach to solar steam generation.”

The approach itself is relatively simple: Since steam is generated at the surface of a liquid, Ghasemi looked for a material that could both efficiently absorb sunlight and generate steam at a liquid’s surface.

After trials with multiple materials, he settled on a thin, double-layered, disc-shaped structure. Its top layer is made from graphite that the researchers exfoliated by placing the material in a microwave. The effect, Chen says, is “just like popcorn”: The graphite bubbles up, forming a nest of flakes. The result is a highly porous material that can better absorb and retain solar energy.

The structure’s bottom layer is a carbon foam that contains pockets of air to keep the foam afloat and act as an insulator, preventing heat from escaping to the underlying liquid. The foam also contains very small pores that allow water to creep up through the structure via capillary action.

As sunlight hits the structure, it creates a hotspot in the graphite layer, generating a pressure gradient that draws water up through the carbon foam. As water seeps into the graphite layer, the heat concentrated in the graphite turns the water into steam. The structure works much like a sponge that, when placed in water on a hot, sunny day, can continuously absorb and evaporate liquid.

The researchers tested the structure by placing it in a chamber of water and exposing it to a solar simulator — a light source that simulates various intensities of solar radiation. They found they were able to convert 85 percent of solar energy into steam at a solar intensity 10 times that of a typical sunny day.

Ghasemi says the structure may be designed to be even more efficient, depending on the type of materials used.

“There can be different combinations of materials that can be used in these two layers that can lead to higher efficiencies at lower concentrations,” Ghasemi says. “There is still a lot of research that can be done on implementing this in larger systems.”

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

Solar steam generation by heat localization by Hadi Ghasemi, George Ni, Amy Marie Marconnet, James Loomis, Selcuk Yerci, Nenad Miljkovic, & Gang Chen. Nature Communications 5, Article number: 4449 doi:10.1038/ncomms5449 Published 21 July 2014

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

Trapping gases left from nuclear fuels

A July 20, 2014 news item on ScienceDaily provides some insight into recycling nuclear fuel,

When nuclear fuel gets recycled, the process releases radioactive krypton and xenon gases. Naturally occurring uranium in rock contaminates basements with the related gas radon. A new porous material called CC3 effectively traps these gases, and research appearing July 20 in Nature Materials shows how: by breathing enough to let the gases in but not out.

The CC3 material could be helpful in removing unwanted or hazardous radioactive elements from nuclear fuel or air in buildings and also in recycling useful elements from the nuclear fuel cycle. CC3 is much more selective in trapping these gases compared to other experimental materials. Also, CC3 will likely use less energy to recover elements than conventional treatments, according to the authors.

A July 21, 2014 US Department of Energy (DOE) Pacific Northwest National Laboratory (PNNL) news release (also on EurekAlert), which originated the news item despite the difference in dates, provides more details (Note: A link has been removed),

The team made up of scientists at the University of Liverpool in the U.K., the Department of Energy’s Pacific Northwest National Laboratory, Newcastle University in the U.K., and Aix-Marseille Universite in France performed simulations and laboratory experiments to determine how — and how well — CC3 might separate these gases from exhaust or waste.

“Xenon, krypton and radon are noble gases, which are chemically inert. That makes it difficult to find materials that can trap them,” said coauthor Praveen Thallapally of PNNL. “So we were happily surprised at how easily CC3 removed them from the gas stream.”

Noble gases are rare in the atmosphere but some such as radon come in radioactive forms and can contribute to cancer. Others such as xenon are useful industrial gases in commercial lighting, medical imaging and anesthesia.

The conventional way to remove xenon from the air or recover it from nuclear fuel involves cooling the air far below where water freezes. Such cryogenic separations are energy intensive and expensive. Researchers have been exploring materials called metal-organic frameworks, also known as MOFs, that could potentially trap xenon and krypton without having to use cryogenics. Although a leading MOF could remove xenon at very low concentrations and at ambient temperatures admirably, researchers wanted to find a material that performed better.

Thallapally’s collaborator Andrew Cooper at the University of Liverpool and others had been researching materials called porous organic cages, whose molecular structures are made up of repeating units that form 3-D cages. Cages built from a molecule called CC3 are the right size to hold about three atoms of xenon, krypton or radon.

To test whether CC3 might be useful here, the team simulated on a computer CC3 interacting with atoms of xenon and other noble gases. The molecular structure of CC3 naturally expands and contracts. The researchers found this breathing created a hole in the cage that grew to 4.5 angstroms wide and shrunk to 3.6 angstroms. One atom of xenon is 4.1 angstroms wide, suggesting it could fit within the window if the cage opens long enough. (Krypton and radon are 3.69 angstroms and 4.17 angstroms wide, respectively, and it takes 10 million angstroms to span a millimeter.)

The computer simulations revealed that CC3 opens its windows big enough for xenon about 7 percent of the time, but that is enough for xenon to hop in. In addition, xenon has a higher likelihood of hopping in than hopping out, essentially trapping the noble gas inside.

The team then tested how well CC3 could pull low concentrations of xenon and krypton out of air, a mix of gases that included oxygen, argon, carbon dioxide and nitrogen. With xenon at 400 parts per million and krypton at 40 parts per million, the researchers sent the mix through a sample of CC3 and measured how long it took for the gases to come out the other side.

Oxygen, nitrogen, argon and carbon dioxide — abundant components of air — traveled through the CC3 and continued to be measured for the experiment’s full 45 minute span. Xenon however stayed within the CC3 for 15 minutes, showing that CC3 could separate xenon from air.

In addition, CC3 trapped twice as much xenon as the leading MOF material. It also caught xenon 20 times more often than it caught krypton, a characteristic known as selectivity. The leading MOF only preferred xenon 7 times as much. These experiments indicated improved performance in two important characteristics of such a material, capacity and selectivity.

“We know that CC3 does this but we’re not sure why. Once we understand why CC3 traps the noble gases so easily, we can improve on it,” said Thallapally.

To explore whether MOFs and porous organic cages offer economic advantages, the researchers estimated the cost compared to cryogenic separations and determined they would likely be less expensive.

“Because these materials function well at ambient or close to ambient temperatures, the processes based on them are less energy intensive to use,” said PNNL’s Denis Strachan.

The material might also find use in pharmaceuticals. Most molecules come in right- and left-handed forms and often only one form works in people. In additional experiments, Cooper and colleagues in the U.K. tested CC3′s ability to distinguish and separate left- and right-handed versions of an alcohol. After separating left- and right-handed forms of CC3, the team showed in biochemical experiments that each form selectively trapped only one form of the alcohol.

The researchers have provided an image illustrating a CC3 cage,

Breathing room: In this computer simulation, light and dark purple highlight the cavities within the 3D pore structure of CC3. Courtesy:  PNNL

Breathing room: In this computer simulation, light and dark purple highlight the cavities within the 3D pore structure of CC3. Courtesy: PNNL

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

Separation of rare gases and chiral molecules by selective binding in porous organic cages by Linjiang Chen, Paul S. Reiss, Samantha Y. Chong, Daniel Holden, Kim E. Jelfs, Tom Hasell, Marc A. Little, Adam Kewley, Michael E. Briggs, Andrew Stephenson, K. Mark Thomas, Jayne A. Armstrong, Jon Bell, Jose Busto, Raymond Noel, Jian Liu, Denis M. Strachan, Praveen K. Thallapally, & Andrew I. Cooper. Nature Material (2014) doi:10.1038/nmat4035 Published online 20 July 2014

This paper is behind a paywall.

At a distance of less than a light wave, nanocamera takes pictures

A July 17, 2014 University of Illinois College of Engineering news release (also on EurekAlert) features a research breakthrough,

How is it possible to record optically encoded information for distances smaller than the wavelength of light?

Researchers at the University of Illinois at Urbana-Champaign have demonstrated that an array of novel gold, pillar-bowtie nanoantennas (pBNAs) can be used like traditional photographic film to record light for distances that are much smaller than the wavelength of light (for example, distances less than ~600 nm for red light). A standard optical microscope acts as a “nanocamera” whereas the pBNAs are the analogous film.

Here’s an image the researchers have provided to illustrate their work,

We demonstrate the plasmonic equivalent of photographic film for recording optical intensity in the near field. The plasmonic structure is based on gold bowtie nanoantenna arrays fabricated on SiO2 pillars. We show that it can be employed for direct laser writing of image data or recording the polarization structure of optical vector beams.[downloaded from http://pubs.acs.org/doi/abs/10.1021/nl501788a]

We demonstrate the plasmonic equivalent of photographic film for recording optical intensity in the near field. The plasmonic structure is based on gold bowtie nanoantenna arrays fabricated on SiO2 pillars. We show that it can be employed for direct laser writing of image data or recording the polarization structure of optical vector beams.[downloaded from http://pubs.acs.org/doi/abs/10.1021/nl501788a]

The news release describes the technique,

“Unlike conventional photographic film, the effect (writing and curing) is seen in real time,” explained Kimani Toussaint, an associate professor of mechanical science and engineering, who led the research. “We have demonstrated that this multifunctional plasmonic film can be used to create optofluidic channels without walls. Because simple diode lasers and low-input power densities are sufficient to record near-field optical information in the pBNAs, this increases the potential for optical data storage applications using off-the-shelf, low-cost, read-write laser systems.”

“Particle manipulation is the proof-of-principle application,” stated Brian Roxworthy, first author of the group’s paper, “Multifunctional Plasmonic Film for Recording Near-Field Optical Intensity,” published in the journal, Nano Letters. “Specifically, the trajectory of trapped particles in solution is controlled by the pattern written into the pBNAs. This is equivalent to creating channels on the surface for particle guiding except that these channels do not have physical walls (in contrast to those optofluidics systems where physical channels are fabricated in materials such as PDMS).”

To prove their findings, the team demonstrated various written patterns—including the University’s “Block I” logo and brief animation of a stick figure walking—that were either holographically transferred to the pBNAs or laser-written using steering mirrors (see video).

The news release concludes with,

“We wanted to show the analogy between what we have made and traditional photographic film,” Toussaint added. “There’s a certain cool factor with this. However, we know that we’re just scratching the surface since the use of plasmonic film for data storage at very small scales is just one application. Our pBNAs allow us to do so much more, which we’re currently exploring.”

The researchers noted that the fundamental bit size is currently set by the spacing of the antennas at 425-nm. However, the pixel density of the film can be straightforwardly reduced by fabricating smaller array spacing and a smaller antenna size, as well as using a more tightly focusing lens for recording.

“For a standard Blu-ray/DVD disc size, that amounts to a total of 28.6 gigabites per disk,” Roxworthy added. “With modifications to array spacing and antenna features, it’s feasible that this value can be scaled to greater than 75 gigabites per disk. Not to mention, it can be used for other exciting photonic applications, such as lab-on-chip nanotweezers or sensing.”

“In our new technique, we use controlled heating via laser illumination of the nanoantennas to change the plasmonic response instantaneously, which shows an innovative but easy way to fabricate spatially changing plasmonic structures and thus opens a new avenue in the field of nanotech-based biomedical technologies and nano optics,”  said Abdul Bhuiya, a co-author and member of the research team.

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

Multifunctional Plasmonic Film for Recording Near-Field Optical Intensity by Brian J. Roxworthy, Abdul M. Bhuiya, V. V. G. Krishna Inavalli, Hao Chen, and Kimani C. Toussaint , Jr. Nano Lett., Article ASAP DOI: 10.1021/nl501788a Publication Date (Web): July 14, 2014
Copyright © 2014 American Chemical Society

This paper is behind a paywall.

Mathematicians, political scientists, and cake cutting

If you have a sibling, you’ve likely fought at least once over who got the biggest or ‘best’ piece of cake.  (I do and I did.) In any event, it seems that mathematicians and political scientists have been working on a scheme to avoid disputes over cake.

[downloaded from http://link.springer.com/article/10.1007%2Fs00283-013-9442-0#page-1]

A July 16, 2014 Springer news release (also on EurekAlert) describes the quest for fairly sized cake slices and how that might apply to real life issues such as sharing property,

The next time your children quibble about who gets to eat which part of a cake, call in some experts on the art of sharing. Mathematician Julius Barbanel of Union College, and political scientist Steven Brams of New York University, both in the US, published an algorithm in Springer’s The Mathematical Intelligencer by which they show how to optimally share cake between two people efficiently, in equal pieces and in such a way that no one feels robbed.

The cut-and-choose method to share divisible goods has been regarded as fair and envy-free since Biblical times, when Abraham divided land equally, and Lot could choose the part he wanted. But being free of envy is not the only consideration when sharing something. What happens when more than two cuts can be made, or when people prefer different, specific sections of whatever is to be divided? Barbanel and Brams believe that with a giveback procedure it is possible to make a perfect division between two people that is efficient, equitable and void of jealousy.

An objective referee (such as a Mom or a computer) is essential to the plan. The potential cake eaters first tell the referee which parts of the delicacy they value most. In mathematical terms these are called someone’s probability density functions, or pdfs. The referee then marks out the cake at all points were the pdfs of the disgruntled would-be cake eaters cross, and assigns portions. If at this point the two parties receive the same size of cake, the task is over. If not, the giveback process starts.

The party who received the larger part of the cake during the first round must give a part of it back to the other person, starting with those parts in which the ratio of their pdfs is the smallest. This goes on until the parties value their portions equally, and have the same volume of cake to eat. This method only works with a finite number of cuts if the players’ pdfs are straight-lined, or are so-called piecewise linear sections.

The researchers believe the method can be used to share cake and other divisible goods such as land. In the case of beachfront property being co-owned by two developers, for example, it can help to determine who gets what strips of land to build on based on the pieces of land they value most.

“This allocation is not only equitable but also envy-free and efficient – that is, perfect,” says Barbanel.

“This approach focuses on proving the existence of efficient and envy-free divisions, not on providing algorithms to finding them,” emphasizes Brams.

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

Two-Person Cake Cutting: The Optimal Number of Cuts by Julius B. Barbanel and Steven J. Brams. The Mathematical Intelligencer March 2014 DOI 10.1007/s00283-013-9442.

This paper is behind a paywall although there is a free preview available and a special summer discount (30%) on the purchase price until July 31, 2014.

Turing film, Imitation Game, gets European première at London Film Festival; will world première be at Toronto International Film Fest?

There’s quite a cast associated with “Imitation Game,” a film which focuses on Alan Turing’s years as a codebreaker during World War II and will be enjoying its European première at the BFI [British Film Institute?] London Film Festival on Oct. 8, 2014 according to a July 21, 2014 BBC (British Broadcasting Corporation) news item online.

The cast includes Mark Strong as,

Major General Sir Stewart Graham Menzies, KCB KCMG DSO MC (/ˈmɪŋɪz/; 30 January 1890 – 29 May 1968) was Chief of MI6 (SIS), British Secret Intelligence Service, during and after the Second World War. (see the rest of Menzies’ Wikipedia entry here along with all the links)

Strong always offers a compelling performance and he is billed alongside, Benedict Cumberbatch (BCC Sherlock) as Alan Turing, Keira Knightley as Turing’s friend and colleague in what are described in the BBC online news item as “extraordinary performances,”

The Imitation Game follows the race against time as Turing and his team at the top-secret codebreaking centre at Bletchley Park attempt to decipher German naval messages and help end the war.

Matthew Goode, Mark Strong, Rory Kinnear and Charles Dance also star.

Festival director Clare Stewart said the film featured “extraordinary performances”.

A July 21, 2014 news item by Nick Vivarelli for Variety describes the film and upcoming première (aka preem; Note: A link has been removed),

Norwegian helmer Morten Tyldum’s Alan Turing drama “The Imitation Game,” with Benedict Cumberbatch and Keira Knightley, will open the 58th BFI London Film Festival on October 8th, marking the pic’s European preem.

The biopic based on the life story of the crypotgrapher and mathematician who cracked the German “Enigma Code” during WWII, and was later prosecuted by the British government in the early 1950s for being a homosexual, will screen in London’s Odeon Leicester Square, with key cast, Cumberbatch and Knightley, and helmer Tyldum, expected on the red carpet.

A July 21, 2014 article by Andrew Pulver for the Guardian notes the emphasis on the Oct. 8, 2014 event as a ‘European’ première,

Directed by Morten Tyldum and co-starring Keira Knightley as Turing’s friend and fellow code-breaker Joan Clarke, the London film festival screening is being billed as a European premiere, which suggests the film’s world premiere will be held outside Europe, most likely at the Toronto film festival in early September.

The London film festival runs from 8-19 October [2014].

Here’s a trailer for the film; (it looks pretty good to me),


Widespread release for the film is scheduled for early November 2014. I have not been able to confirm that “Imitation Game” will be at TIFF in early September 2014.

Turing has been mentioned here many times but my June 20, 2012 posting is the most comprehensive,

Alan Turing led one of those lives that seems more like an act of fiction than anything else. Born June 23, 1912, the centenary is being celebrated in the UK and internationally as he was an instrumental figure in the field of science.

He had quite an extraordinary life unto a death, which could be described as enigmatic. It is not clear whether he committed suicide or accidentally killed himself with cyanide. A half-eaten apple was found by his bedside but never tested for poison. (Snow White was Turing’s favourite fairy tale.) His death came after shortly completing a court-ordered course of chemical castration (he could have chosen imprisonment instead) on being found guilty of homosexuality.

You can find out more about the BFI London Film Festival here and about the Toronto International Film Festival here. There is a July 21, 2014 posting by Sarah on Lainey Gossip speculation about this film and Benedict Cumberbatch’s chances of an Academy Award (Oscar) nomination along with speculation about possible competitors.

ETA July 22, 2014, 1130 PDT: Imitation Game is getting its Canadian première at the 2014 TIFF (media release PDF p. 5). H/T Lainey Gossip (scroll down about 40% of the way.