This week's Catch-Up checks out viruses to make you healthy, GPS mobile phones as emergency tools, Googling the Earth, solar nanotechnology, and a breakthrough in space propulsion.
Phage Therapy: Bacteriophages are viruses that (typically) kill bacteria; they work their magic by infecting the nucleus of a bacterial cell with their own DNA, hijacking it to make more viruses. A growing number of bioscientists are looking at bacteriophages as, essentially, self-replicating antibiotics. Mike the Mad Biologist has more details:
Ultimately, the advantage and the disadvantage of phage therapy is that is a narrow spectrum treatment: a particular phage works against a certain species (or even a subset of a species). The disadvantage is that you have to know something about the infectious bacterium such as what species it is, and such diagnoses can take several days–time many patients do not have. On other hand, the evolution of resistance will be limited to a much smaller group of bacteria (and you can always try to isolate, or evolve in the laboratory, new phage, making the development process substantially cheaper).
Phage therapy won't be a magic bullet. But, hopefully, phage therapy will become one more tool we can use to stop the evolution of antibiotic resistance.
Few doctors use phage therapy yet, although it was frequently employed -- largely out of desperation -- in the Soviet Union; the one remaining former Soviet facility for making therapeutic bacteriophages was located in the Republic of Georgia, and has been shuttered by the ongoing civil war.
Mobile Phones, GPS and Emergencies: Mobile phones aren't just for talking with one's friends any more, and among the variety of additional uses is a serious role in emergencies and disasters. Unfortunately, many emergency-related applications are third-party hacks, and few carriers understand the device's disaster utility. Japanese telecom KDDI, however, has started to roll out mobile phones equipped with global positioning system (GPS) technology, and is pushing the devices specifically as tools for emergency use. In one case, KDDI worked with Kyoto University to test the use of mobile phone GPS as a means of guiding evacuees in the event of an earthquake or other disaster.
About 30 students took part in the experiment, held in the vicinity of the university's campus in Kyoto, bringing with them GPS-equipped phones designed to display the nearest evacuation center. A computer system determined the students' locations, searched the nearest of five evacuation centers in the area and displayed a map on the mobile phones, according to those involved with the experiment.
In another example, KDDI is now carrying a phone that combines GPS with an emergency alert buzzer. KDDI intends the phone to appeal to parents needing a phone for their children, but concept of a loud alarm on a phone makes a great deal of sense, both to head off crime and to aid rescuers in case of emergency. I suspect it won't be too long before both features are fairly standard across the spectrum of phones.
Google Earth Basics: Google finally released a version of its Google Earth application for the Macintosh this week, and with the influx of new users, Frank Taylor of the Google Earth Blog has assembled a set of basic instructions and suggestions for using this startlingly powerful free application.
(Via The Map Room)
Nano-solar: It's becoming increasingly clear that nanotechnology will be the battering ram that makes solar power ubiquitous, as there's a growing number of techniques for using nano-scale materials in ways that increase efficiency and reduce costs.
Boingboing's David Pescovitz, writing for Berkeley Lab Notes, details the nanocrystal photovoltaic breakthrough we discussed back in October of 2005. Materials Science grad student Ilan Gur and his team figured out how to make photovoltaic materials out of inorganic nanocrystals, combining the resilience of traditional silicon photovoltaics with the ease of production and low cost of solar power polymers. Their only real drawback: a lowly 3% conversion efficiency. But no worries:
"If you can make this technology practical, you could imagine that people would be able to make solar cells where they don't have the tremendous capital needed to build plants, like in developing nations," Gur says. [...] "If we can produce this for as cheap as we hope, the efficiency doesn't have to be so high because you could just install more of the material," Gur says. "There are certainly places where people would trade space for energy."
The flip side of the nano-solar revolution can be found in the work of Richard Schaller, Melissa Petruska and Victor Klimov at the Los Alamos National Laboratory. Late last month, they published an article in Applied Physics Letters detailing a method of using nanocrystal "quantum dots" to boost the efficiency of photovoltaics made out of less-expensive materials like zinc or polymers. The potential boost is dramatic:
Los Alamos National Laboratory researchers have shown that it is possible to produce two or more electrons from a single photon using many kinds of semiconductor materials, not just the more exotic lead selenium of initial carrier multiplication experiments. [...] Solar cells made with semiconductor nanocrystals could use carrier multiplication to boost solar efficiency to 60 percent, according to the researchers. Today's state-of-the-art solar cells are less than 40 percent efficient.
Now what we need is to see what happens when you combine these two techniques. Cheap, rugged nanocrystal photovoltaics with better-than-silicon conversion efficiency is pretty much the Holy Grail of solar power research -- and it might even be possible to achieve.
Engage: Researchers at the European Space Agency and the Australian National University have come up with a design for an ion engine that is four times as powerful -- and four times more fuel-efficient -- than the current state-of-the-art design. Ion engines are essentially electric rockets, propelling space probes by shooting out ions (generally atoms stripped of their electrons) as exhaust. Currently, ion engines put out a very low thrust, but can do so for very long periods of time, thereby building up to a fairly high velocity; this makes them ideal for long-term probes, but less-useful for any manned missions. This breakthrough may change all that:
Once ready, these engines will be able to propel spacecraft to the outermost planets, the newly discovered planetoids beyond Pluto and even further, into the unknown realm of interstellar space beyond the Solar System. Closer to home, these supercharged ion engines could figure prominently in the human exploration of space. With an adequate supply of electrical power, a small cluster of larger, high power versions of the new engine design would provide enough thrust to propel a crewed spacecraft to Mars and back.
Of course, if Walter Dröscher and Jochem Häuser are correct, that fancy new ion engine will be left in the space dust of hyperdrive ships.
In "Heim Quantum Theory for Space Propulsion Physics," the two physicists describe a propulsion technology using an obscure -- but generally accepted -- element of quantum theory. The drive would make it possible to get to Mars in as little as five hours, and might be possible using present-day technology. What's more, because the system involves "multidimensional hyperspace," Dröscher and Häuser claim it might be possible to take advantage of differing natural laws, including faster speeds for the speed of light. In short, they describe an honest-to-goodness warp drive.
All of this would be the amusing fringe science New Scientist likes to throw our way now and again, were it not for the paper being accepted for presentation at the 2005 American Institute of Physics conference and being awarded "best paper in the nuclear and future flight category" prize by the American Institute of Aeronautics and Astronautics at its 2005 conference. In short, although many of the physicists contacted by New Scientist claimed not be able to parse the dense, translated prose of the paper, at least some of those who could thought it serious enough to be part of major academic and professional conferences.
See what you think of the idea: you can download the paper (PDF) at the University of Insbruck website.
The use of phages to fight disease is also mentioned in Sinclair Lewis' novel Arrowsmith.
I can't believe that the Heim Drive (if I may call it that) would work.
On the other hand, I would gladly relearn physics if it did :). A few years of wasted education is nothing compared to what the engine could potentially deliver.