From the monthly archives:

September 2010

Stronger than carbon nanotubes:
Polyynes and the prospects for carbyne

September 29, 2010

Carbon nanotubes have a reputation for being strongest possible fibers, but polyyne chains are stronger, as measured by the critical strength/density ratio: Polyyne carbon-carbon bonds are stronger than the bonds in graphene and nanotubes, and the bonds are all are aligned with the axis of the fiber, the optimal geometry for carrying tensile stress. A [...]

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Antioxidants block cell repair —
New information and what it may mean

September 26, 2010

Abstract: Antioxidants inhibit basal autophagy and block the induction of autophagy by calorie restriction and other means. Because this effect inhibits the central mechanism of cell repair, it helps explain why dietary antioxidants have failed to deliver their expected benefits to health and longevity. The nature of the effect suggests prudent modifications to popular supplementation [...]

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Out of the memory-hole:
A historian speaks out on nanotechnology

September 24, 2010

A recent retrospective on the U.S. National Nanotechnology Initiative (Nature, 1 Sept 2010) repeats the story that strong excitement about nanotechnology “began at the birth of the NNI [established in 2000] and peaked in the middle of the decade”.
This paints a strange and false picture. Excitement launched the bureaucracy, not vice versa, and it [...]

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Trehalose vs. trehalase

September 18, 2010

Update, 3 March 2011: Trehalose reportedly “has good blood–brain barrier penetration”.

My recent post, “Trehalose, autophagy, and brain repair” references a few of the papers that suggest potential advantages to absorbing and circulating some of the wonder-sugar, trehalose. The problem is trehalase.

– Trehalose –

In us animals, trehalase metabolizes trehalose into glucose, but the details differ widely. [...]

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Trehalose, autophagy, and brain repair: Sweet

September 15, 2010

Abstract of recent abstracts:
Trehalose induces autophagy.
Autophagy induces neuronal repair.
Starvation induces autophagy.
Trehalose goes well with coffee and tea.

– Trehalose –Now on sale

Quote: “Macroautophagy (here simply called autophagy) is a cellular housekeeping process that degrades and recycles long-lived proteins, large protein aggregates, and even entire organelles like mitochondria. The term autophagy is of Greek origin and translates [...]

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Boron is the new carbon…

September 13, 2010

…and I read it in EMBO Reports.
Declaring that “boronate esters are the new [reversible covalent linkers in foldamers and self-assembly]” would be less playful and entertaining, but I say something like that here: “Exploiting strong, covalent bonds for self assembly of robust nanosystems”.

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Forcible, reversible mechanochemistry

September 12, 2010

Chemists at Duke and Stanford have prepared polymers that break and reform C–C bonds when yanked and relaxed (paper here). They engineered these polymers to contain cyclopropane rings in their backbones, using the electron-withdrawing effect of a bridging –CF2– to weaken the critical bond (see figure). Applying intense ultrasound to these polymers in solution [...]

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Chemists deserve more credit (2):
   The 150th anniversary
    of the first international science conference

September 10, 2010

In this week’s Chemical & Engineering News, the American Chemical Society marks the 150th anniversary of the world’s first scientific conference — yes, a chemistry conference — held Sept. 3, 1860, in Karlsruhe, Germany.

August Kekulé Atomic scientist,conference organizer

Friedrich August Kekulé von Stradonitz The guy who gets the credit

August Kekulé suggested idea of holding a conference, [...]

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Which came first, the Nano or the NNI?

September 5, 2010

A news article in this week’s Nature discusses the origin of the U.S. National Nanotechnology Initiative, but the story sets some of the causality in reverse. The story outlines how science advocacy at the Federal level in 1999 led to presidential and congressional support in 2000, and says that afterward…
…a certain amount of hype [...]

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Metacognition, then and now
(a crisp example)

September 2, 2010

As a follow-on to recent posts here and here, I’d like to offer a crisp example of the standards of cognitive reflection that were taught in the once-upon-a-time United States: a sample from Studies in Civics (1897), a high school textbook.
TO STUDENTS.
You will notice in chapter one that at the close of nearly every paragraph [...]

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High-school civics and minds,
1890 and now

September 2, 2010

A comment on my recent post, “The problem: a metacognition deficit,” reminded me of a striking illustration of cultural change, the level of the language and content of a book used in the 1890s to teach high school civics (available in plain text, a big pdf and simulated in-browser book ). It reeks of a [...]

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