Tag Archives: Ben Schiller

Carbon nanotubes sense spoiled food

CNT_FoodSpolage

Courtesy: MIT (Massachusetts Institute of Technology)

I love this .gif; it says a lot without a word. However for details, you need words and here’s what an April 15, 2015 news item on Nanowerk has to say about the research illustrated by the .gif,

MIT [Massachusetts Institute of Technology] chemists have devised an inexpensive, portable sensor that can detect gases emitted by rotting meat, allowing consumers to determine whether the meat in their grocery store or refrigerator is safe to eat.

The sensor, which consists of chemically modified carbon nanotubes, could be deployed in “smart packaging” that would offer much more accurate safety information than the expiration date on the package, says Timothy Swager, the John D. MacArthur Professor of Chemistry at MIT.

An April 14, 2015 MIT news release (also on EurekAlert), which originated the news item, offers more from Dr. Swager,

It could also cut down on food waste, he adds. “People are constantly throwing things out that probably aren’t bad,” says Swager, who is the senior author of a paper describing the new sensor this week in the journal Angewandte Chemie.

This latest study is builds on previous work at Swager’s lab (Note: Links have been removed),

The sensor is similar to other carbon nanotube devices that Swager’s lab has developed in recent years, including one that detects the ripeness of fruit. All of these devices work on the same principle: Carbon nanotubes can be chemically modified so that their ability to carry an electric current changes in the presence of a particular gas.

In this case, the researchers modified the carbon nanotubes with metal-containing compounds called metalloporphyrins, which contain a central metal atom bound to several nitrogen-containing rings. Hemoglobin, which carries oxygen in the blood, is a metalloporphyrin with iron as the central atom.

For this sensor, the researchers used a metalloporphyrin with cobalt at its center. Metalloporphyrins are very good at binding to nitrogen-containing compounds called amines. Of particular interest to the researchers were the so-called biogenic amines, such as putrescine and cadaverine, which are produced by decaying meat.

When the cobalt-containing porphyrin binds to any of these amines, it increases the electrical resistance of the carbon nanotube, which can be easily measured.

“We use these porphyrins to fabricate a very simple device where we apply a potential across the device and then monitor the current. When the device encounters amines, which are markers of decaying meat, the current of the device will become lower,” Liu says.

In this study, the researchers tested the sensor on four types of meat: pork, chicken, cod, and salmon. They found that when refrigerated, all four types stayed fresh over four days. Left unrefrigerated, the samples all decayed, but at varying rates.

There are other sensors that can detect the signs of decaying meat, but they are usually large and expensive instruments that require expertise to operate. “The advantage we have is these are the cheapest, smallest, easiest-to-manufacture sensors,” Swager says.

“There are several potential advantages in having an inexpensive sensor for measuring, in real time, the freshness of meat and fish products, including preventing foodborne illness, increasing overall customer satisfaction, and reducing food waste at grocery stores and in consumers’ homes,” says Roberto Forloni, a senior science fellow at Sealed Air, a major supplier of food packaging, who was not part of the research team.

The new device also requires very little power and could be incorporated into a wireless platform Swager’s lab recently developed that allows a regular smartphone to read output from carbon nanotube sensors such as this one.

The funding sources are interesting, as I am appreciating with increasing frequency these days (from the news release),

The researchers have filed for a patent on the technology and hope to license it for commercial development. The research was funded by the National Science Foundation and the Army Research Office through MIT’s Institute for Soldier Nanotechnologies.

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

Single-Walled Carbon Nanotube/Metalloporphyrin Composites for the Chemiresistive Detection of Amines and Meat Spoilage by Sophie F. Liu, Alexander R. Petty, Dr. Graham T. Sazama, and Timothy M. Swager. Angewandte Chemie International Edition DOI: 10.1002/anie.201501434 Article first published online: 13 APR 2015

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This article is behind a paywall.

There are other posts here about the quest to create food sensors including this Sept. 26, 2013 piece which features a critique (by another blogger) about trying to create food sensors that may be more expensive than the item they are protecting, a problem Swager claims to have overcome in an April 17, 2015 article by Ben Schiller for Fast Company (Note: Links have been removed),

Swager has set up a company to commercialize the technology and he expects to do the first demonstrations to interested clients this summer. The first applications are likely to be for food workers working with meat and fish, but there’s no reason why consumers shouldn’t get their own devices in due time.

There are efforts to create visual clues for food status. But Swager says his method is better because it doesn’t rely on perception: it produces hard data that can be logged and tracked. And it also has potential to be very cheap.

“The resistance method is a game-changer because it’s two to three orders of magnitude cheaper than other technology. It’s hard to imagine doing this cheaper,” he says.

Comparing techniques, citizen science to expert science

Thanks to Ben Schiller for his Mar. 20, 2013 Fast Company article for this tidbit about an intriguing study carried out by the University of East Anglia,

Research in the Caribbean comparing the abilities of two teams of divers–one using traditional scientific methods, the other using a volunteer technique–found that the amateurs were capable of producing equal, if not better, data. After 44 underwater surveys over two weeks, the volunteers found 137 species of fish, compared to the professionals’ 106.

A University of East Anglia (UEA) Mar. 13, 2013 news release provides more detail about the research and its implications,

Research published today in the journal Methods in Ecology and Evolution shows that methods to record marine diversity used by amateurs returned results consistent with techniques favoured by peer-reviewed science.

The findings give weight to the growing phenomenon of citizen science, which sees data crowd-sourced from an army of avid twitchers, divers, walkers and other wildlife enthusiasts.

The field study compared methods used by ‘citizen’ SCUBA divers with those used by professional scientists, to measure the variety of fish species in three Caribbean sites.

Two teams of 12 divers made 144 separate underwater surveys across the sites over four weeks.

While the traditional scientific survey revealed sightings of 106 different types of fish, the volunteer technique detected greater marine diversity with a total of 137 in the same waters.

Dr Ben Holt, from UEA’s school of Biological Sciences, led the research in partnership with the Centre for Marine Resource Studies in the Caribbean and the University of Copenhagen, Denmark.

He said: “The results of this study are important for the future of citizen science and the use of data collected by these programs. Allowing volunteers to use flexible and less standardised methods has important consequences for the long term success of citizen science programs. Amateur enthusiasts typically do not have the resources or training to use professional methodology. [emphasis mine] Our study demonstrates the quality of data collected using a volunteer method can match, and in some respects exceed, protocols used by professional scientists.

If the study demonstrates that using a volunteer method matches or, in some cases, exceeds a method (protocol) used by professional scientists, why make the comment about “amateur enthusiasts” not having the resources or training to use professional methods? It would seem that in this study professional methodology was not as effective as volunteer methodology.  That said, I don’t believe we should be replacing professional scientists/methods with volunteers/volunteer methods. There’s more to a scientific inquiry than data collection but this indication that data collected by and the methods used by volunteers have validity when compared to professionally collected data opens up some opportunities for volunteers and scientists.

Holt continues (from the news release),

“Very few, if any, scientific groups can collect data on the scale that volunteer groups can, so our proof that both methods return consistent results is very encouraging for citizen science in general.

“I think we will really see the value of volunteer schemes increase in future. We’re living in a world that’s changing very significantly. Environmental changes are having a big impact on ecosystems around us so we need to harness new ways of measuring the effect.

“For example Lion fish is an invasive species which was not in the Caribbean until roughly 10 years ago. They have now become a real problem in many areas and this invasion has been tracked using volunteer data. Following our study, scientists can have more confidence when using these data to consider the impact of threats, such as invasive species, on the wider natural communities.

“It is important to note that our study does not consider the abilities of the individuals performing the surveys and this is also an important consideration for any large scale biodiversity program. By addressing these issues we can make important steps towards enabling the large pool of volunteer enthusiasts to help professional researchers by collecting valuable data across many ecosystems.”

The research was carried out in under water sites close to South Caicos in the Turks and Caicos Islands.

Here’s an image of the Lionfish, the gorgeous, yet  invasive, species mentioned by Holt,

Antennata Lionfish, picture taken in Zoo Schönbrunn, Vienna, Austria (downloaded from http://en.wikipedia.org/wiki/File:MC_Rotfeuerfisch.jpg)

Antennata Lionfish, picture taken in Zoo Schönbrunn, Vienna, Austria (downloaded from http://en.wikipedia.org/wiki/File:MC_Rotfeuerfisch.jpg)

Here’s a citation and a link to Holt’s article,

Comparing diversity data collected using a protocol designed for volunteers with results from a professional alternative by Ben G. Holt, Rodolfo Rioja-Nieto, M. Aaron MacNeil, Jan Lupton,  & Carsten Rahbek. Methods in Ecology and Evolution, DOI: 10.1111/2041-210X.12031 Article first published online: 12 MAR 2013

This article is open access.

Brain-to-brain communication, organic computers, and BAM (brain activity map), the connectome

Miguel Nicolelis, a professor at Duke University, has been making international headlines lately with two brain projects. The first one about implanting a brain chip that allows rats to perceive infrared light was mentioned in my Feb. 15, 2013 posting. The latest project is a brain-to-brain (rats) communication project as per a Feb. 28, 2013 news release on *EurekAlert,

Researchers have electronically linked the brains of pairs of rats for the first time, enabling them to communicate directly to solve simple behavioral puzzles. A further test of this work successfully linked the brains of two animals thousands of miles apart—one in Durham, N.C., and one in Natal, Brazil.

The results of these projects suggest the future potential for linking multiple brains to form what the research team is calling an “organic computer,” which could allow sharing of motor and sensory information among groups of animals. The study was published Feb. 28, 2013, in the journal Scientific Reports.

“Our previous studies with brain-machine interfaces had convinced us that the rat brain was much more plastic than we had previously thought,” said Miguel Nicolelis, M.D., PhD, lead author of the publication and professor of neurobiology at Duke University School of Medicine. “In those experiments, the rat brain was able to adapt easily to accept input from devices outside the body and even learn how to process invisible infrared light generated by an artificial sensor. So, the question we asked was, ‘if the brain could assimilate signals from artificial sensors, could it also assimilate information input from sensors from a different body?'”

Ben Schiller in a Mar. 1, 2013 article for Fast Company describes both the latest experiment and the work leading up to it,

First, two rats were trained to press a lever when a light went on in their cage. Press the right lever, and they would get a reward–a sip of water. The animals were then split in two: one cage had a lever with a light, while another had a lever without a light. When the first rat pressed the lever, the researchers sent electrical activity from its brain to the second rat. It pressed the right lever 70% of the time (more than half).

In another experiment, the rats seemed to collaborate. When the second rat didn’t push the right lever, the first rat was denied a drink. That seemed to encourage the first to improve its signals, raising the second rat’s lever-pushing success rate.

Finally, to show that brain-communication would work at a distance, the researchers put one rat in an cage in North Carolina, and another in Natal, Brazil. Despite noise on the Internet connection, the brain-link worked just as well–the rate at which the second rat pushed the lever was similar to the experiment conducted solely in the U.S.

The Duke University Feb. 28, 2013 news release, the origin for the news release on EurekAlert, provides more specific details about the experiments and the rats’ training,

To test this hypothesis, the researchers first trained pairs of rats to solve a simple problem: to press the correct lever when an indicator light above the lever switched on, which rewarded the rats with a sip of water. They next connected the two animals’ brains via arrays of microelectrodes inserted into the area of the cortex that processes motor information.

One of the two rodents was designated as the “encoder” animal. This animal received a visual cue that showed it which lever to press in exchange for a water reward. Once this “encoder” rat pressed the right lever, a sample of its brain activity that coded its behavioral decision was translated into a pattern of electrical stimulation that was delivered directly into the brain of the second rat, known as the “decoder” animal.

The decoder rat had the same types of levers in its chamber, but it did not receive any visual cue indicating which lever it should press to obtain a reward. Therefore, to press the correct lever and receive the reward it craved, the decoder rat would have to rely on the cue transmitted from the encoder via the brain-to-brain interface.

The researchers then conducted trials to determine how well the decoder animal could decipher the brain input from the encoder rat to choose the correct lever. The decoder rat ultimately achieved a maximum success rate of about 70 percent, only slightly below the possible maximum success rate of 78 percent that the researchers had theorized was achievable based on success rates of sending signals directly to the decoder rat’s brain.

Importantly, the communication provided by this brain-to-brain interface was two-way. For instance, the encoder rat did not receive a full reward if the decoder rat made a wrong choice. The result of this peculiar contingency, said Nicolelis, led to the establishment of a “behavioral collaboration” between the pair of rats.

“We saw that when the decoder rat committed an error, the encoder basically changed both its brain function and behavior to make it easier for its partner to get it right,” Nicolelis said. “The encoder improved the signal-to-noise ratio of its brain activity that represented the decision, so the signal became cleaner and easier to detect. And it made a quicker, cleaner decision to choose the correct lever to press. Invariably, when the encoder made those adaptations, the decoder got the right decision more often, so they both got a better reward.”

In a second set of experiments, the researchers trained pairs of rats to distinguish between a narrow or wide opening using their whiskers. If the opening was narrow, they were taught to nose-poke a water port on the left side of the chamber to receive a reward; for a wide opening, they had to poke a port on the right side.

The researchers then divided the rats into encoders and decoders. The decoders were trained to associate stimulation pulses with the left reward poke as the correct choice, and an absence of pulses with the right reward poke as correct. During trials in which the encoder detected the opening width and transmitted the choice to the decoder, the decoder had a success rate of about 65 percent, significantly above chance.

To test the transmission limits of the brain-to-brain communication, the researchers placed an encoder rat in Brazil, at the Edmond and Lily Safra International Institute of Neuroscience of Natal (ELS-IINN), and transmitted its brain signals over the Internet to a decoder rat in Durham, N.C. They found that the two rats could still work together on the tactile discrimination task.

“So, even though the animals were on different continents, with the resulting noisy transmission and signal delays, they could still communicate,” said Miguel Pais-Vieira, PhD, a postdoctoral fellow and first author of the study. “This tells us that it could be possible to create a workable, network of animal brains distributed in many different locations.”

Will Oremus in his Feb. 28, 2013 article for Slate seems a little less buoyant about the implications of this work,

Nicolelis believes this opens the possibility of building an “organic computer” that links the brains of multiple animals into a single central nervous system, which he calls a “brain-net.” Are you a little creeped out yet? In a statement, Nicolelis adds:

We cannot even predict what kinds of emergent properties would appear when animals begin interacting as part of a brain-net. In theory, you could imagine that a combination of brains could provide solutions that individual brains cannot achieve by themselves.

That sounds far-fetched. But Nicolelis’ lab is developing quite the track record of “taking science fiction and turning it into science,” says Ron Frostig, a neurobiologist at UC-Irvine who was not involved in the rat study. “He’s the most imaginative neuroscientist right now.” (Frostig made it clear he meant this as a complement, though skeptics might interpret the word less charitably.)

The most extensive coverage I’ve given Nicolelis and his work (including the Walk Again project) was in a March 16, 2012 post titled, Monkeys, mind control, robots, prosthetics, and the 2014 World Cup (soccer/football), although there are other mentions including in this Oct. 6, 2011 posting titled, Advertising for the 21st Century: B-Reel, ‘storytelling’, and mind control.  By the way, Nicolelis hopes to have a paraplegic individual (using technology Nicolelis is developing for the Walk Again project) kick the opening soccer/football to the 2014 World Cup games in Brazil.

While there’s much excitement about Nicolelis and his work, there are other ‘brain’ projects being developed in the US including the Brain Activity Map (BAM), which James Lewis notes in his Mar. 1, 2013 posting on the Foresight Institute blog,

A proposal alluded to by President Obama in his State of the Union address [Feb. 2013] to construct a dynamic “functional connectome” Brain Activity Map (BAM) would leverage current progress in neuroscience, synthetic biology, and nanotechnology to develop a map of each firing of every neuron in the human brain—a hundred billion neurons sampled on millisecond time scales. Although not the intended goal of this effort, a project on this scale, if it is funded, should also indirectly advance efforts to develop artificial intelligence and atomically precise manufacturing.

As Lewis notes in his posting, there’s an excellent description of BAM and other brain projects, as well as a discussion about how these ideas are linked (not necessarily by individuals but by the overall direction of work being done in many labs and in many countries across the globe) in Robert Blum’s Feb. (??), 2013 posting titled, BAM: Brain Activity Map Every Spike from Every Neuron, on his eponymous blog. Blum also offers an extensive set of links to the reports and stories about BAM. From Blum’s posting,

The essence of the BAM proposal is to create the technology over the coming decade
to be able to record every spike from every neuron in the brain of a behaving organism.
While this notion seems insanely ambitious, coming from a group of top investigators,
the paper deserves scrutiny. At minimum it shows what might be achieved in the future
by the combination of nanotechnology and neuroscience.

In 2013, as I write this, two European Flagship projects have just received funding for
one billion euro each (1.3 billion dollars each). The Human Brain Project is
an outgrowth of the Blue Brain Project, directed by Prof. Henry Markram
in Lausanne, which seeks to create a detailed simulation of the human brain.
The Graphene Flagship, based in Sweden, will explore uses of graphene for,
among others, creation of nanotech-based supercomputers. The potential synergy
between these projects is a source of great optimism.

The goal of the BAM Project is to elaborate the functional connectome
of a live organism: that is, not only the static (axo-dendritic) connections
but how they function in real-time as thinking and action unfold.

The European Flagship Human Brain Project will create the computational
capability to simulate large, realistic neural networks. But to compare the model
with reality, a real-time, functional, brain-wide connectome must also be created.
Nanotech and neuroscience are mature enough to justify funding this proposal.

I highly recommend reading Blum’s technical description of neural spikes as understanding that concept or any other in his post doesn’t require an advanced degree. Note: Blum holds a number of degrees and diplomas including an MD (neuroscience) from the University of California at San Francisco and a PhD in computer science and biostatistics from California’s Stanford University.

The Human Brain Project has been mentioned here previously. The  most recent mention is in a Jan. 28, 2013 posting about its newly gained status as one of two European Flagship initiatives (the other is the Graphene initiative) each meriting one billion euros of research funding over 10 years. Today, however, is the first time I’ve encountered the BAM project and I’m fascinated. Luckily, John Markoff’s Feb. 17, 2013 article for The New York Times provides some insight into this US initiative (Note: I have removed some links),

The Obama administration is planning a decade-long scientific effort to examine the workings of the human brain and build a comprehensive map of its activity, seeking to do for the brain what the Human Genome Project did for genetics.

The project, which the administration has been looking to unveil as early as March, will include federal agencies, private foundations and teams of neuroscientists and nanoscientists in a concerted effort to advance the knowledge of the brain’s billions of neurons and gain greater insights into perception, actions and, ultimately, consciousness.

Moreover, the project holds the potential of paving the way for advances in artificial intelligence.

What I find particularly interesting is the reference back to the human genome project, which may explain why BAM is also referred to as a ‘connectome’.

ETA Mar.6.13: I have found a Human Connectome Project Mar. 6, 2013 news release on EurekAlert, which leaves me confused. This does not seem to be related to BAM, although the articles about BAM did reference a ‘connectome’. At this point, I’m guessing that BAM and the ‘Human Connectome Project’ are two related but different projects and the reference to a ‘connectome’ in the BAM material is meant generically.  I previously mentioned the Human Connectome Project panel discussion held at the AAAS (American Association for the Advancement of Science) 2013 meeting in my Feb. 7, 2013 posting.

* Corrected EurkAlert to EurekAlert on June 14, 2013.