Music File Compressed 1,000 Times Smaller than MP3

20-Second Clarinet Solo Fits in a Single Kilobyte

Researchers at the University of Rochester have digitally reproduced music in a file nearly 1,000 times smaller than a regular MP3 file.

The music, a 20-second clarinet solo, is encoded in less than a single kilobyte, and is made possible by two innovations: recreating in a computer both the real-world physics of a clarinet and the physics of a clarinet player.

The achievement, announced today at the International Conference on Acoustics Speech and Signal Processing held in Las Vegas, is not yet a flawless reproduction of an original performance, but the researchers say it's getting close.

"This is essentially a human-scale system of reproducing music," says Mark Bocko, professor of electrical and computer engineering and co-creator of the technology. "Humans can manipulate their tongue, breath, and fingers only so fast, so in theory we shouldn't really have to measure the music many thousands of times a second like we do on a CD. As a result, I think we may have found the absolute least amount of data needed to reproduce a piece of music."

In replaying the music, a computer literally reproduces the original performance based on everything it knows about clarinets and clarinet playing. Two of Bocko's doctoral students, Xiaoxiao Dong and Mark Sterling, worked with Bocko to measure every aspect of a clarinet that affects its sound—from the backpressure in the mouthpiece for every different fingering, to the way sound radiates from the instrument. They then built a computer model of the clarinet, and the result is a virtual instrument built entirely from the real-world acoustical measurements.

The team then set about creating a virtual player for the virtual clarinet. They modeled how a clarinet player interacts with the instrument including the fingerings, the force of breath, and the pressure of the player's lips to determine how they would affect the response of the virtual clarinet. Then, says Bocko, it's a matter of letting the computer "listen" to a real clarinet performance to infer and record the various actions required to create a specific sound. The original sound is then reproduced by feeding the record of the player's actions back into the computer model.

At present the results are a very close, though not yet a perfect, representation of the original sound.

"We are still working on including 'tonguing,' or how the player strikes the reed with the tongue to start notes in staccato passages," says Bocko. "But in music with more sustained and connected notes the method works quite well and it's difficult to tell the synthesized sound from the original."

As the method is refined the researchers imagine that it may give computer musicians more intuitive ways to create expressive music by including the actions of a virtual musician in computer synthesizers. And although the human vocal tract is highly complex, Bocko says the method may in principle be extended to vocals as well.

The current method handles only a single instrument at a time, however in other work in the University's Music Research Lab with post-doctoral researcher Gordana Velikic and Dave Headlam, professor of music theory at the University of Rochester's Eastman School of Music, the team has produced a method of separating multiple instruments in a mix so the two methods can be combined to produce a very compact recording.

Bocko believes that the quality will continue to improve as the acoustic measurements and the resulting synthesis algorithms become more accurate, and he says this process may represent the maximum possible data compression of music.

"Maybe the future of music recording lies in reproducing performers and not recording them," says Bocko.

This research is funded by the National Science Foundation.

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'Artificial cell' can make its own genes

An "artificial cell" capable of synthesising genes and making them into proteins has been developed by researchers in the US.

Cells are governed by genes which provide instructions for making proteins that carry out the cell's functions.

The postage stamp-sized machine able to make and express its own genes offers a fast and cheap new way of making "designer" proteins not found in nature. It could ultimately help scientists test how individual patients will react to specific drugs.

"At very small volumes in the order of tens of nanolitres, we can construct completely synthetic genes and express these genes to yield functional protein," David Kong of Massachusetts Institute of Technology (MIT), Boston, US, told New Scientist.

The artificial cell resembles a computer chip. It is made from layers of rubber, forming a solid chip shot through with a network of tiny passages and chambers.

"This rubber has lines and features that are the size we need for our microfluidic chambers, channels and valves," says Peter Carr, who was also involved with the work. "With a few layers of this rubber, put together carefully, you can build a fairly complex device."

Shining example

After building separate gene synthesis and protein expressions chips, the researchers have now successfully integrated the two into a single system.

The first part of the device synthesises the genes using enzymes to join together DNA strands from a pool of short templates. The finished genes are then copied to produce many versions of the final product. Cycles of heating and cooling control the enzymes carrying out the reactions.

Once the genes have been made, a series of tiny pumps mixes them with the enzymes and cell extracts needed to make proteins.

First, a set of enzymes must convert the DNA of the genes into RNA. This RNA is then mixed with extracts from bacterial cells containing amino acids from which proteins are made, and ribosomes, the cell structures that "read" RNA and assemble the amino acids into finished protein.

In test runs, the artificial cell was used to make a fluorescent protein from jellyfish. Other proteins can also be designed with a fluorescent portion. "We can see very clearly that we have functional glowing protein, so we know it works," says Kong.

Cancer simulation

Kong believes his new device will be valuable for researchers investigating novel protein designs. The team is now exploring ways to make much larger devices containing thousands of reaction chambers that can synthesis many different proteins at once.

The diminutive devices shrink the cost as well as the size of the protein design process, says Kong, because smaller amounts of expensive reagents are needed. "You can do 100,000 experiments for the price that people can normally do 50 experiments," he adds.

Carr hopes that in the future such devices will be complex enough for use in cancer treatment. "I could start with the genetic information from a patient, program it into the device that we are working on, and essentially run a kind of simulation of how a drug might affect their cancer,” he explains.

Other groups have shown that proteins can be expressed in artificial conditions, but the new device has taken the idea of an artificial cell one step closer to reality, says Hugh Fan of the University of Florida, Gainesville, US, who was not involved in the study.

"This group has advanced the field by showing the integration of gene synthesis with protein expression in one device,” he told New Scientist.

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Nano Tanks Could Store Hydrogen in Microscopic 'Soccer Balls'

While hydrogen gas and fuel cells remain far-off realities for solving the fuel crunch, new computer models of interlocked carbon chambers (above in gray) have proven to store hydrogen (white) at similar pressures to the cores of huge planets. (Photograph by Jennifer Bogo; illustrations courtesy of Nano Letters/ACS)

If engineering could keep up with the hype, we would all be driving hydrogen cars by now, whirring about in emissions-free wonderboxes like the Jetsons. But hydrogen, for all its potential, presents some serious technical challenges. As a gas, it requires gigantic, heavy tanks to store, and as a liquid, it must be kept impracticably cold—below 423 degrees Fahrenheit. Researchers at Rice University, however, recently tested a third option.

“What if, instead of one big tank, you have millions and billions of tiny little nanoscale containers? Would it be safer? How much pressure would they contain?” asks Dr. Boris Yakobson, lead author of a study that recently modeled hydrogen storage inside tiny hollow carbon structures called buckyballs. “We wanted to understand the limits—how many molecules of hydrogen, in principle, you can place inside the carbon cage before it just mechanically breaks.”

Picture a soccer ball a few hundred thousand times smaller than a grain of salt. This, essentially, is what buckyballs look like—strong, hollow cages of interlocked carbon. The idea that something could be held inside these cages isn’t new, but Yakobson and his colleagues are the first to accurately estimate how much pressure the walls could withstand, using computer modeling to push them to their breaking point.

The space inside a 60-atom buckyball would ordinarily be big enough for just a single atom of hydrogen. But as the researchers simulated adding more and more, the walls of the cage continued to hold, withstanding pressures close to those at the cores of Jupiter and Saturn. Ultimately, the team estimated its buckyball could hold 58 hydrogen atoms before bursting, squeezing the normally gaseous atoms into a near metallic state.

“This is not practical for storage, certainly, because it’s too small,” Yakobson says. “But then you say, okay, now what if I go to larger cages? The shell can still sustain the same tension.” Modeling a 60-atom buckyball enables researchers to scale up to cages made of thousands of carbon atoms and measuring several nanometers across. To the naked eye, a few billion of these would look like a kind of gray, metallic powder, similar to graphite dust.

Buckyballs do exist in nature—the soot from burning candles, for instance, contains buckyballs, split from vaporized wax by the heat of the flame—and scientists have been synthesizing them in labs since the mid 1980s. This study, though, is purely theoretical. No one yet knows how to put that much hydrogen inside a buckyball, or how to get it out afterwards.

Yakobson is currently working on other nanostructures he thinks might be better suited to hydrogen storage, including tiny cylindrical tubes that would compress hydrogen atoms inside with a sort of microscopic piston. In the future, such structures could also be used to contain radioactive isotopes for cancer treatment, or to subject tiny amounts of compounds to gigantic pressures in the lab for study.

“From a scientific point of view, hydrogen is a perfect material, but from an engineering point of view, you wind up having significant energy losses when you make it and store it and try to move it around,” says Dennis Witmer, a professor at the University of Alaska who regularly evaluates hydrogen fuel cells and other alternative energy sources.

“It looks to me like this is a really cool piece of science,” Witmer says, “but in terms of expecting to fuel a car with them anytime in my lifetime, I don’t expect it to happen.”

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