Tag Archives: copper

Nanotwinned copper materials with nanovoids are damage-tolerant with regard to radiation

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The research comes out of the Texas A&M University, from a May 29, 2015 news item on Azonano,

Material performance in extreme radiation environments is central to the design of future nuclear reactors. Radiation in metallic materials typically induces significant damage in the form of dislocation loops and continuous void growth, manifested as void swelling. In certain metallic materials with low-to-intermediate stacking fault energy, such as Cu [copper] and austenitic stainless steels, void swelling can be significant and lead to substantial degradation of mechanical properties.

By using in situ heavy ion irradiation in a transmission electron microscope (in collaboration with M.A. Kirk at IVEM facility at Argonne National Lab), Zhang’s [Xinghang Zhang] student, Dr. Youxing Chen, reported a surprising phenomena: during radiation of nanotwinned Cu, preexisting nanovoids disappeared.

A May 28, 2015 Texas A & M University news release, which originated the news item, expands on the theme,

The self-healing capability of Cu arises from the existence of three-dimensional coherent and incoherent twin boundary networks. Such a network enables capture and rapid transportation of radiation induced point defects and their clusters to nanovoids (as evidenced by in situ radiation experiments and molecular dynamics simulations performed in collaboration with Jian Wang at Los Alamos National Laboratory), and thus lead to the mutual elimination of defect clusters and nanovoids.

This study also introduces the concept that deliberate introduction of nanovoids in conjunction with nanotwins may enable unprecedented radiation tolerance in metallic materials. [emphasis mine] The mobile twin boundaries are swift carriers that load and transfer “customers” (defect clusters), and nanovoids are also necessary to accommodate these “customers.” The in situ radiation study also shows that after annihilation of nanovoids, the self-healing capability of nanotwinned Cu is degraded, highlighting the significance of nanovoids. The concept developed from this study, the combination of nanovoids with nanotwin networks, may also stimulate the design of damage tolerant materials in general that are subjected other extreme environments, such as high stress and high pressure impact.

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

Damage-tolerant nanotwinned metals with nanovoids under radiation environments by Y. Chen, K Y. Yu, Y. Liu, S. Shao, H. Wang, M. A. Kirk, J. Wang, & X. Zhang. Nature Communications 6, Article number: 7036 doi:10.1038/ncomms8036 Published 24 April 2015

This paper is open access.

Solar cells and copper sprouts

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First, Washington University in St. Louis (WUSTL; located in Missouri, US) announced a discovery about solar cells, then, the university announced a commitment to increase solar output by Fall 2014. Whether these two announcements are linked by some larger policy or strategy is not clear to me but it’s certainly an interesting confluence of events.

An April 26, 2014 news item on Azonano describes the researchers’ discovery,

By looking at a piece of material in cross section, Washington University in St. Louis engineer Parag Banerjee, PhD, and his team discovered how copper sprouts grass-like nanowires that could one day be made into solar cells.

Banerjee, assistant professor of materials science and an expert in working with nanomaterials, Fei Wu, graduate research assistant, and Yoon Myung, PhD, a postdoctoral research associate, also took a step toward making solar cells and more cost-effective.

An April 21, 2014 WUSTL news release by Beth Miller, which originated the news item, describes the research in some detail,

Banerjee and his team worked with copper foil, a simple material similar to household aluminum foil. When most metals are heated, they form a thick metal oxide film. However, a few metals, such as copper, iron and zinc, grow grass-like structures known as nanowires, which are long, cylindrical structures a few hundred nanometers wide by many microns tall. They set out to determine how the nanowires grow.

“Other researchers look at these wires from the top down,” Banerjee says. “We wanted to do something different, so we broke our sample and looked at it from the side view to see if we got different information, and we did.”

…

The team used Raman spectroscopy, a technique that uses light from a laser beam to interact with molecular vibrations or other movements. They found an underlying thick film made up of two different copper oxides (CuO and Cu2O) that had narrow, vertical columns of grains running through them. In between these columns, they found grain boundaries that acted as arteries through which the copper from the underlying layer was being pushed through when heat was applied, creating the nanowires.

“We’re now playing with this ionic transport mechanism, turning it on and off and seeing if we can get some different forms of wires,” says Banerjee, who runs the Laboratory for Emerging and Applied Nanomaterials (L.E.A.N.).

Like solar cells, the nanowires are single crystal in structure, or a continuous piece of material with no grain boundaries, Banerjee says.

“If we could take these and study some of the basic optical and electronic properties, we could potentially make solar cells,” he says. “In terms of optical properties, copper oxides are well-positioned to become a solar energy harvesting material.”

This work may be useful in other applications according to the news release,

The find may also benefit other engineers who want to use single crystal oxides in scientific research. Manufacturing single crystal Cu2O for research is very expensive, Banerjee says, costing up to about $1,500 for one crystal.

“But if you can live with this form that’s a long wire instead of a small crystal, you can really use it to study basic scientific phenomena,” Banerjee says.

Banerjee’s team also is looking for other uses for the nanowires, including acting as a semiconductor between two materials, as a photocatalyst, a photovoltaic or an electrode for splitting water.

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

Unravelling transient phases during thermal oxidation of copper for dense CuO nanowire growth by Fei Wu, Yoon Myunga and Parag Banerjee.  CrystEngComm, 2014,16, 3264-3267. DOI: 10.1039/C4CE00275J First published online 26 Feb 2014

This article is behind a paywall.

Shortly after the research announcement, WUSTL made this ‘solar’ announcement via an April 29, 2014 news release by Neil Schoenherr,

Washington University in St. Louis is moving forward with a bold and impactful plan to increase solar output on all campuses by 1,150 percent over current levels by this fall. The project demonstrates the university’s commitment to sustainable operations and to reducing its environmental impact in the St. Louis region and beyond.

This spring and early summer, the university will add a total of 379 kilowatts (kw) of solar on university-owned property throughout the region. Prior to this installation, the university had 33 kw that were installed as demonstration projects.

I suspect the two announcements reflect synchronicity or, perhaps, my tendency to see and develop patterns.

You probably can’t poison yourself by eating too many nanoparticles

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Researchers, Ingrid Bergin in the Unit for Laboratory Animal Medicine, at the University of Michigan in Ann Arbor and Frank Witzmann in the Department of Cellular and Integrative Physiology, at Indiana University School of Medicine, in Indianapolis, have stated that ingesting food and beverage (translated by me from the more scientific description) with nanoparticles (at today’s current levels) is unlikely to prove toxic. A June 26, 2013 Inderscience news release on EurekAlert describes the researchers’ research and their conclusions,

Writing in a forthcoming issue of the International Journal of Biomedical Nanoscience and Nanotechnology, researchers have compared existing laboratory and experimental animal studies pertaining to the toxicity of nanoparticles most likely to be intentionally or accidentally ingested. Based on their review, the researchers determined ingestion of nanoparticles at likely exposure levels is unlikely to cause health problems, at least with respect to acute toxicity. Furthermore, in vitro laboratory testing, which often shows toxicity at a cellular level, does not correspond well with in vivo testing, which tends to show less adverse effects.

Ingrid Bergin in the Unit for Laboratory Animal Medicine, at the University of Michigan in Ann Arbor and Frank Witzmann in the Department of Cellular and Integrative Physiology, at Indiana University School of Medicine, in Indianapolis, explain that the use of particles that are in the nano size range (from 1 billionth to 100 billionths of a meter in diameter, 1-100 nm, other thereabouts) are finding applications in consumer products and medicine. These include particles such as nano-silver, which is increasingly used in consumer products and dietary supplements for its purported antimicrobial properties. Nanoparticles can have some intriguing and useful properties because they do not necessarily behave in the same chemical and physical ways as non-nanoparticle versions of the same material.

Nanoparticles are now used as natural flavor enhancers in the form of liposomes and related materials, food pigments and in some so-called “health supplements”. They are also used in antibacterial toothbrushes coated with silver nanoparticles, for instance in food and drink containers and in hygienic infant feeding equipment. They are also used to carry pharmaceuticals to specific disease sites in the body to reduce side effects. Nanoparticles actually encompass a very wide range of materials from pure metals and alloys, to metal oxide nanoparticles, and carbon-based and plastic nanoparticles. Because of their increasing utilization in consumer products, there has been concern over whether these small scale materials could have unique toxicity effects when compared to more traditional versions of the same materials.

Difficulties in assessing the health risks of nanoparticles include the fact that particles of differing materials and shapes can have different properties. Furthermore, the route of exposure (e.g. ingestion vs. inhalation) affects the likelihood of toxicity. The U.S. researchers evaluated the current literature specifically with respect to toxicity of ingested nanoparticles. They point out that, in addition to intentional ingestion as with dietary supplements, unintentional ingestion can occur due to nanoparticle presence in water or as a breakdown product from coated consumer goods. Inhaled nanoparticles also represent an ingestion hazard since they are coughed up, swallowed, and eliminated through the intestinal tract.

Based on their review, the team concludes that, “Ingested nanoparticles appear unlikely to have acute or severe toxic effects at typical levels of exposure.” Nevertheless, they add that the current literature is inadequate to assess whether nanoparticles can accumulate in tissues and have long-term effects or whether they might cause subtle alterations in gut microbial populations. The researchers stress that better methods are needed for correlating particle concentrations used for cell-based assessment of toxicity with the actual likely exposure levels to body cells. Such methods may lead to better predictive value for laboratory in vitro testing, which currently over-predicts toxicity of ingested nanoparticles as compared to in vivo testing.

The researchers focused specifically on ingestion via the gastrointestinal tract which I take to mean that they focused largely on nanoparticles in food (eaten) and liquid (swallowed).

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

Nanoparticle toxicity by the gastrointestinal route: evidence and knowledge gaps by Ingrid L. Bergin; Frank A. Witzmann.  Int. J. of Biomedical Nanoscience and Nanotechnology, 2013 Vol.3, No.1/2, pp.163 – 210.  DOI: 10.1504/IJBNN.2013.054515

I think the abstract further helps to understand the research focus,

The increasing interest in nanoparticles for advanced technologies, consumer products, and biomedical applications has led to great excitement about potential benefits but also concern over the potential for adverse human health effects. The gastrointestinal tract represents a likely route of entry for many nanomaterials, both directly through intentional ingestion or indirectly via nanoparticle dissolution from food containers or by secondary ingestion of inhaled particles. Additionally, increased utilisation of nanoparticles may lead to increased environmental contamination and unintentional ingestion via water, food animals, or fish. The gastrointestinal tract is a site of complex, symbiotic interactions between host cells and the resident microbiome. Accordingly, evaluation of nanoparticles must take into consideration not only absorption and extraintestinal organ accumulation but also the potential for altered gut microbes and the effects of this perturbation on the host. The existing literature was evaluated for evidence of toxicity based on these considerations. Focus was placed on three categories of nanomaterials: nanometals and metal oxides, carbon-based nanoparticles, and polymer/dendrimers with emphasis on those particles of greatest relevance to gastrointestinal exposures.

The article is behind a paywall.

I last mentioned Frank Witzmann here in a May 8, 2013 posting titled, US multicenter (Nano GO Consortium) study of engineered nanomaterial toxicology.

When your kinks and your defects are your strength: the truth about copper’s coherent twin boundaries

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There’s perfection and then there’s imperfection in this story about the nanoscale. From the May 19, 2013 news release on EurekAlert,

One of the basic principles of nanotechnology is that when you make things extremely small—one nanometer is about five atoms wide, 100,000 times smaller than the diameter of a human hair—they are going to become more perfect.

“Perfect in the sense that their arrangement of atoms in the real world will become more like an idealized model,” says University of Vermont engineer Frederic Sansoz, “with smaller crystals—in for example, gold or copper—it’s easier to have fewer defects in them.”

And eliminating the defects at the interface separating two crystals, or grains, has been shown by nanotechnology experts to be a powerful strategy for making materials stronger, more easily molded, and less electrically resistant—or a host of other qualities sought by designers and manufacturers.

Scientists thought they’d found perfection in 2004 (from the news release),

Since 2004, when a seminal paper came out in Science, materials scientists have been excited about one special of arrangement of atoms in metals and other materials called a “coherent twin boundary” or CTB.

Based on theory and experiment, these coherent twin boundaries are often described as “perfect,” appearing like a perfectly flat, one-atom-thick plane in computer models and electron microscope images.

Over the last decade, a body of literature has shown these coherent twin boundaries—found at the nanoscale within the crystalline structure of common metals like gold, silver and copper—are highly effective at making materials much stronger while maintaining their ability to undergo permanent change in shape without breaking and still allowing easy transmission of electrons—an important fact for computer manufacturing and other electronics applications.

It turns out that not all coherent twin boundaries are ‘perfect’ (from the news release),

A team of scientists, including Sansoz, a professor in UVM’s College of Engineering and Mathematical Sciences, and colleagues from the Lawrence Livermore National Laboratory and elsewhere, write in the May 19 edition of Nature Materials that coherent twin boundaries found in copper “are inherently defective.”

With a high-resolution electron microscope, using a more powerful technique than has ever been used to examine these boundaries, they found tiny kink-like steps and curvatures in what had previously been observed as perfect.

Even more surprising, these kinks and other defects appear to be the cause of the coherent twin boundary’s strength and other desirable qualities.

“Everything we have learned on these materials in the past 10 years will have to be revisited with this new information,” Sansoz says

The work was performed at the Lawrence Livermore National Laboratory (from the news release),

The experiment, led by Morris Wang at the Lawrence Livermore Lab, applied a newly developed mapping technique to study the crystal orientation of CTBs in so-called nanotwinned copper and “boom—it revealed these defects,” says Sansoz.

This real-world discovery conformed to earlier intriguing theoretical findings that Sansoz had been making with “atomistic simulations” on a computer. The lab results sent Sansoz back to his computer models where he introduced the newly discovered “kink” defects into his calculations. Using UVM’s Vermont Advanced Computing Center, he theoretically confirmed that the kink defects observed by the Livermore team lead to “rather rich deformation processes at the atomic scale,” he says, that do not exist with perfect twin boundaries.

With the computer model, “we found a series of completely new mechanisms,” he says, for explaining why coherent twin boundaries simultaneously add strength and yet also allow stretching (what scientists call “tensile ductility”)— properties that are usually mutually exclusive in conventional materials.

It seems to me that scientists keep discovering that it’s the imperfections and defects which give rise to strength and, often, beauty. I hope this time they remember what they’ve discovered.

For those who need to know more, here’s a citation for and link to the paper,

Defective twin boundaries in nanotwinned metals by Y. Morris Wang, Frederic Sansoz, Thomas LaGrange, Ryan T. Ott, Jaime Marian, Troy W. Barbee Jr, & Alex V. Hamza. Nature Materials (2013) doi:10.1038/nmat3646 Published online 19 May 2013

This paper is behind a paywall.

Soldiers sniff overripe fruit

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Technically speaking the soldiers are not sniffing the fruit, it’s the sensing technology developed at the Massachusetts Institute of Technology’s Institute for Soldier Nanotechnologies which is doing the ‘sniffing’. From the April 30, 2012 news item on Nanowerk (I have removed some links),

Every year, U.S. supermarkets lose roughly 10 percent of their fruits and vegetables to spoilage, according to the Department of Agriculture. To help combat those losses, MIT chemistry professor Timothy Swager and his students have built a new sensor that could help grocers and food distributors better monitor their produce.

The new sensors, described in the journal Angewandte Chemie (“Selective Detection of Ethylene Gas Using Carbon Nanotube-based Devices: Utility in Determination of Fruit Ripeness”), can detect tiny amounts of ethylene, a gas that promotes ripening in plants. Swager envisions the inexpensive sensors attached to cardboard boxes of produce and scanned with a handheld device that would reveal the contents’ ripeness.

…

Detecting gases to monitor the food supply is a new area of interest for Swager, whose previous research has focused on sensors to detect explosives or chemical and biological warfare agents.

Here’s how the technology works (from the April 30, 2012 news release by Anne Trafton for MIT News),

Funded by the U.S. Army Office of Research through MIT’s Institute for Soldier Nanotechnologies, the MIT team built a sensor consisting of an array of tens of thousands of carbon nanotubes: sheets of carbon atoms rolled into cylinders that act as “superhighways” for electron flow.

To modify the tubes to detect ethylene gas, the researchers added copper atoms, which serve as “speed bumps” to slow the flowing electrons. “Anytime you put something on these nanotubes, you’re making speed bumps, because you’re taking this perfect, pristine system and you’re putting something on it,” Swager says.

Copper atoms slow the electrons a little bit, but when ethylene is present, it binds to the copper atoms and slows the electrons even more. By measuring how much the electrons slow down — a property also known as resistance — the researchers can determine how much ethylene is present.

To make the device even more sensitive, the researchers added tiny beads of polystyrene, which absorbs ethylene and concentrates it near the carbon nanotubes. With their latest version, the researchers can detect concentrations of ethylene as low as 0.5 parts per million. The concentration required for fruit ripening is usually between 0.1 and one part per million.

The researchers tested their sensors on several types of fruit — banana, avocado, apple, pear and orange — and were able to accurately measure their ripeness by detecting how much ethylene the fruits secreted.

It looks like the technology will be commercialized in the not too distant future (from the Trafton news release) here’s why,

John Saffell, the technical director at Alphasense, a company that develops sensors, describes the MIT team’s approach as rigorous and focused. “This sensor, if designed and implemented correctly, could significantly reduce the level of fruit spoilage during shipping,” he says.

“At any given time, there are thousands of cargo containers on the seas, transporting fruit and hoping that they arrive at their destination with the correct degree of ripeness,” adds Saffell, who was not involved in this research. “Expensive analytical systems can monitor ethylene generation, but in the cost-sensitive shipping business, they are not economically viable for most of shipped fruit.”

Swager has filed for a patent on the technology and hopes to start a company to commercialize the sensors. In future work, he plans to add a radio-frequency identification (RFID) chip to the sensor so it can communicate wirelessly with a handheld device that would display ethylene levels. The system would be extremely cheap — about 25 cents for the carbon nanotube sensor plus another 75 cents for the RFID chip, Swager estimates.

“This could be done with absolutely dirt-cheap electronics, with almost no power,” he says.

I should mention that a couple of students were part of the MIT research team with Birgit Esser being the lead author and Jan Schnorr also contributing to the paper in Angewandte Chemie.

Could nanoparticles in your mouthwash affect for your cells?

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The first news item I’m going to highlight was posted on Nanowerk, March 8, 2012 and is focused on the use of silver nanoparticles in mouthwashes and dentures to prevent yeast infections,

Yeasts which cause hard-to-treat mouth infections are killed using silver nanoparticles in the laboratory, scientists have found. These yeast infections, caused by Candida albicans and Candida glabrata target the young, old and immuno-compromised. Professor Mariana Henriques, University of Minho [Portugal], and her colleagues hope to test silver nanoparticles in mouthwash and dentures as a potential preventative measure against these infections.

Professor Henriques and her team, who published their research in the Society for Applied Microbiology’s journal Letters in Applied Microbiology(“Silver nanoparticles: influence of stabilizing agent and diameter on antifungal activity against Candida albicans and Candida glabrata biofilms”), looked at the use of different sizes of silver nanoparticles to determine their anti-fungal properties …

The scientists used artificial biofilms in conditions which mimic those of saliva as closely as possible. They then added different sizes and concentrations of silver nanoparticles and found that different sizes of nanoparticles were equally effective at killing the yeasts. Due to the diversity of the sizes of nanoparticles demonstrating anti-fungal properties the researchers hope this will enable the nanoparticles to be used in many different applications.

Some researchers have expressed concerns around the safety of nanoparticle use but the authors stress this research is at an early stage and extensive safety trials will be carried out before any product reaches the market. [emphasis mine]

Following on the notion of safety and gargling silver nanoparticles, coincidentally, there was another news item also dated March 8, 2012 on Nanowerk, this one about the impact that nanoparticles may have on nutrient uptake,

Nanoparticles are everywhere. From cosmetics and clothes, to soda and snacks. But as versatile as they are, nanoparticles also have a downside, say researchers at Binghamton University and Cornell University in a recent paper published in the journal Nature Nanotechnology (“Oral exposure to polystyrene nanoparticles affects iron absorption”). These tiny particles, even in low doses, could have a big impact on our long-term health.

According to lead author of the article, Gretchen Mahler, assistant professor of bioengineering at Binghamton University, much of the existing research on the safety of nanoparticles has been on the direct health effects. But what Mahler, Michael L. Shuler of Cornell University and a team of researchers really wanted to know was what happens when someone gets constant exposure in small doses – the kind you’d get if you were taken a drug or supplement that included nanoparticles in some form. [e.g. silver nanoparticles in your mouthwash or on your dentures]

“We thought that the best way to measure the more subtle effects of this kind of intake was to monitor the reaction of intestinal cells,” said Mahler. “And we did this in two ways: in vitro, through human intestinal-lining cells that we had cultured in the lab; and in vivo, through the intestinal linings of live chickens. Both sets of results pointed to the same thing – that exposure to nanoparticles influences the absorption of nutrients into the bloodstream.”

As for why the researchers focused on iron and tested polystyrene nanoparticles (from the news item),

The uptake of iron, an essential nutrient, was of particular interest due to the way it is absorbed and processed through the intestines. The way Mahler and the team tested this was to use polystyrene nanoparticles because of its easily traceable fluorescent properties.

“What we found was that for brief exposures, iron absorption dropped by about 50 percent,” said Mahler. “But when we extended that period of time, absorption actually increased by about 200 percent. It was very clear – nanoparticles definitely affects iron uptake and transport.”

While acute oral exposure caused disruptions to intestinal iron transport, chronic exposure caused a remodeling of the intestinal villi – the tiny, finger-like projections that are vital to the intestine’s ability to absorb nutrients – making them larger and broader, thus allowing iron to enter the bloodstream much faster.

As to whether these changes are good or bad the researchers don’t speculate. They do have plans for more testing,

calcium,
copper,
zinc, and
fat-soluble vitamins A, D, E and K

They don’t mention any changes in the types of nanoparticles they might be testing in future.

In any event, our bodies have changed a lot over the centuries, you just have to visit a pyramid in Egypt or a museum that holds medieval armour to observe that humans were once much shorter than we are today.

Viruses mine for copper at the University of BC; microscopy at the University of Victoria; the Henry Louis Gates Jr. affair, human nature, & human enhancement

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Professor Scott Dunbar at the University of British Columbia’s (Canada) Norman B. Keevil Institute of Mining Engineering needed to partner with colleagues Sue Curtis and Ross MacGillivray from the Centre for Blood Research and the Department of Biochemistry and Molecular Biology after (from the media release on Nanowerk News),

“I read an article about bacteriophage – viruses that infect bacteria – being used to create nanodevices in which proteins on the phage surface are engineered to bind to gold and zinc sulfide,” says Dunbar. “And it struck me: if zinc sulfide, why not copper sulfide? And if so, then it might be possible to use these bio-engineered proteins to separate common economic sulfide minerals from waste during mineral extraction.”

Together the researchers have developed a procedure called “biopanning.” It’s a kind of genetic engineering which could lead to some useful applications.

It turns out that the phage that bind to a mineral do affect the mineral surfaces, causing them to have a different electrical charge than other minerals. The proteins on the phage also form links to each other leading to aggregation of the specific sulfide particles. “The physical and chemical changes caused by phage may be the basis for a highly selective method of mineral separation with better recovery. Another possible application is bioremediation, where metals are removed from contaminated water” says Dunbar.

In other BC news, the University of Victoria (Canada) will be getting a new microscope which senses at subatomic levels. (From the media release on Azonano),

The new microscope-called a Scanning Transmission Electron Holography Microscope (STEHM) — will use an electron beam and holography techniques to observe the inside of materials and their surfaces to an expected resolution as small as one-fiftieth the size of an atom.

This is being done in collaboration with Hitachi High-Technologies which is building the microscope in Japan and installing it at U Vic in late 2010. The microscope will be located in a specially adapted room where work to prepare and calibrate it will continue until it becomes operational sometime in 2011.

After my recent series on robots and human enhancement, I feel moved to comment on the situation in the US vis a vis Henry Louis Gates, Jr. and his arrest by the police officer, James Crowley. It’s reported here and elsewhere that neither the recording of the 911 call nor the concerned neighbour who made the call support Sergeant Crowley’s contention that the two men allegedly breaking into the house were described as ‘black’.

Only the participants know what happened and I don’t fully understand the nuances of race, class, and cultural differences that exist in the US so I can’t comment on anything other than this. It is human to hear what we expect to hear and I have an example from a much less charged situation.

Many years ago, I was transcribing notes from a taped interview (one of my first) for an article that I was writing for a newsletter. As I was transcribing, I noticed that I kept changing words so that the interview subject sounded more like me. They were synonyms but they were my words not his. Over the years I’ve gotten much better at being more exact but I’ve never forgotten how easy it is to insert your pet words (biased or not) when you’re remembering what someone said. Note: I was not in a stressful situation and I could rewind and listen again at my leisure.

I hope that Crowley and Gates, Jr. are able to work this out in some fashion and I really hope that it is done in a way that is respectful to both men and not a rush to a false resolution for the benefit of the cameras. For a more informed discussion of the situation, you may find this essay by Richard Thompson Ford  in Slate helpful. It was written before the recording of the 911 call was made public but I think it still stands.

My reason for mentioning this incident is that human nature tends to assert itself in all kinds of situations including the building of robots and the debates on human enhancement, something I did not mention in my series posted (July 22 – 24, 27, 2009).