u*****8
发帖数: 180 | 1 早上读杂志看到的。
http://www.economist.com/node/21548488
In a paper published last year in the journal Science, Dr Winfree and his
colleague Lulu Qian described the use of strand-displacement cascades to
build circuits of increasing complexity, culminating in a circuit made of 74
different DNA strands (pictured) that was capable of calculating the square
roots of four-digit binary numbers. Together with their colleague Jehoshua
Bruck, they then built a tiny neural network, made up of four interconnected
artificial neurons, using a soup of 112 different interacting DNA strands.
Each neuron was designed to fire when the sum of its input signals exceeded
a certain threshold, and could be configured to assign different weights to
different inputs. Such neural networks can recognise simple patterns, even
when presented with incomplete data.
To test their neural network’s pattern-recognition powers, Dr Qian made up
a game to identify one out of four scientists. Each scientist was
represented by a different set of answers to four yes-or-no questions. A
human player would add to the test tube some (but not all) of the DNA
strands corresponding to one set of answers. The circuit then guessed which
scientist was the closest match, showing its answer using different-coloured
fluorescent signals. The circuit took eight hours to give its answer, but
got it right every time. And this circuit should work in a volume of a cubic
micron (one-millionth of a metre), says Dr Winfree, which is small enough
to fit into many sorts of cell. | b****r
发帖数: 17995 | | j********i
发帖数: 143 | 3 这位钱路路也是出自江南钱氏家族吧。好像钱姓的在美国搞生物的特多，而且都很牛。
钱永健，钱永佑，钱泽南，钱卓，钱煦。 |
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