From the monthly archives:

March 2009

A Revolution
in de novo Protein Engineering Methodology

March 30, 2009

In a recent Nature article, researchers describe the design of a peptide foldamer device (a.k.a. “protein”) that binds and releases oxygen in a way that resembles the heme protein, neuroglobin — and they focus more on the design process than on the design product. They advocate an engineering approach that explicitly rejects aspects of the [...]

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Polyoxometalate Nanostructures

March 29, 2009

My technical talks often include a slide that shows several kinds of atomically precise components that may prove useful in composite nanosystems. One image is labeled “polyoxometalates”, a name that isn’t widely known. I think it should be.
Polyoxometalates (POMs) are molecular structures that are, in effect, atomically precise bits of metal oxide that contain [...]

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Effective Concentration in Self Assembly,
Catalysis, and Mechanosynthesis (2)

March 27, 2009

In my post on effective concentration, I noted that the concentration of water in water (about as high as a real concentration can be) is 55 M, while observed effective concentrations are often >55,000 M. This is puzzling until you realize that, for a molecular collision to result in a reaction, it must typically hit a target [...]

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Atomic Layer Deposition
for Atomically Precise Fabrication (1)

March 23, 2009

I recently posted on a surprising atomically precise fabrication process, and in a comment, Tom Craver remarked that
If a method like this could be combined with Single Layer Deposition , it seems like it’d be getting awfully close to allowing building 3D structures — embedded in a solid, so the next step would be [...]

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Effective Concentration in Self Assembly,
Catalysis, and Mechanosynthesis (1)

March 22, 2009

I find that the concept of “effective concentration” helps to clarify my thinking about molecular processes that include catalysis, self assembly, and mechanosynthesis. The concept applies most directly to reaction rates, and it uses ordinary, solution-phase processes as a reference point.
Reactant concentration and reaction rate
In a relevant and typical case, molecules of type A react [...]

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A High-Performance Polymer
for Nanosytems Engineering

March 19, 2009

Molecular objects made of a nylon-like, high-performance polymer are among the most intricate and functional nanostructures in existence today, and they’re being used to develop increasingly advanced, atomically precise nanotechnologies. This high-performance polymer is really more of a construction kit: Its monomeric parts can be bonded and folded to build atomically precise structures that self-assemble [...]

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Mission of Gravity, Part 2

March 18, 2009

GOCE is now in orbit.
There had been some doubt: the previous ESA spacecraft to ride a Rockot went into the Arctic Ocean. But what is it? — see Mission of Gravity (part 1).

 

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AFM Atom Manipulation: A surprising technique

March 14, 2009

Shortly before I launched Metamodern, Science published a remarkable paper by Sugimoto et al. describing atom-by-atom manipulation of a monatomic layer of tin (Sn) on silicon (Si). The animation to the right shows the steps in constructing a pattern of Si atoms that spells ‘Si’. Each frame is an atomic force microscope image made [...]

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Pyrite Nanomaterials for Solar Photovoltaics

March 13, 2009

A new paper in the journal Environmental Science & Technology assesses the requirements for scaling solar photovoltaic systems to the terawatt levels needed to supply electric power on a global scale. The authors identify iron pyrite, FeS2, as an attractive but unconventional alternative: The raw materials for pyrite aren’t scarce, and both the energy and [...]

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CAD for Nanoengineering: DNA, proteins, and search-intensive design

March 11, 2009

In my previous post I discussed some basic design concerns that arise with atomically precise structures, and focused on materials having crystalline order. However, the ability to make structures like these is now extremely limited. Because they can’t yet be built systematically from smaller building blocks, structures of this general are more likely to be [...]

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CAD for Nanoengineering: Atoms, materials, and nanostructures

March 9, 2009

Computer-aided design of structures on an ordinary scale can ignore atoms, and this is a major simplification. A piece of steel, for example, can typically be treated as a homogenous and isotropic material. The dimensions and angles of a steel component can be chosen freely: With few limitations, a steel plate can be of any [...]

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One Watt, One year, One dollar
(pass it on)

March 8, 2009

For residential customers in the U.S., the average price of electricity has recently* been at $0.115 per kilowatt-hour. This works out to almost exactly $1.00 per Watt-year:
Leave a 100 Watt light bulb on for a year, pay $100.
I found this surprising when I calculated it. The number is simple, memorable, and encourages conservation. Pass it [...]

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