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May 02, 2006
"Apparently the pratfall is the peak of all humor. It's not a pretty picture of the human race, Mike."
IBM's developed something very useful for nanotechnology, a new method for molecule sorting and delivery based on the atomic force microscope.
The method is based on the atomic force microscope (AFM), an instrument invented by an IBM Nobel Laureate 20 years ago that performs nanoscale operations using a tiny cantilever with a cone-shaped tip at its end. When an electrical field is applied to the tip, molecules will slide up or down its surface at characteristic speeds. By modifying the tip's surface and varying the strength and duration of the electric field, different molecular species can be separated from each other within a few milliseconds, more than 1,000 times faster than today's methods.
"Our initial tests used fragments of DNA – one with five base pairs, another with 16," said H. Kumar Wickramasinghe, IBM Fellow and co-developer of several different types of AFMs. "An electric field propelled these molecules down the 11.2-micron length of the AFM tip in 5 and 15 milliseconds, respectively. We controlled the passage of as few as 10 molecules, which indicates that this approach should be very useful for analyzing very small biological samples and in writing extremely small features."
It also has potential for delivering molecules onto a surface with great precision, which may be useful in creating future molecular electronic circuits or lithography features for more conventional nanoelectronics. To demonstrate the technique's initial deposition prowess, the scientists used a single tip to write an outline of IBM's classic 8-bar corporate logo in 59-79-nanometer-wide lines composed of 5-base-pair fragments of DNA. The logo was so small that more than 300 of them would fit on the cross section of a human hair.
"Our new method acts more like an inkjet printer than a fountain pen," Wickramasinghe said. "For example, we write only when the electric field is applied, not continuously while in contact with the surface. We can also control the deposition rate by varying the electric field strength, and our new technique is much less sensitive to the chemical properties of the molecules or the writing surface."
Is the origin of humor in pratfalls and flatulence?
“Witnessing another individual unexpectedly trip or slip (from an awkward bipedal gait?) while simultaneously recognising the non-seriousness of the mishap often elicits laughter in humans today,” says the study, which appears this week in the Quarterly Review of Biology. “Such a mishap could have become a potent elicitor of laughter in early hominids as a result of Pliocene pressures for increased social play.”
Someone's analyzed Pitchfork by the numbers, and it's a little surprising.
There’s no question that Pitchfork is probably the closest thing we’ve got these days to Rolling Stone — 1970s RS, that is — in terms of its influence over fans and artists and its pervasiveness in music-related media. Whether you agree or disagree with that influence is one thing, but it’s hard to deny that it exists. Record stores are increasingly basing the records they stock around the relative merit assigned to albums by Pitchfork, and concert attendence is following those very same trends. In this edition of The More You Know, we examine nearly 8500 reviews on Pitchfork dating back to 1996 to determine if Pitchfork itself is guilty of following trends, or at the very least, having tendencies.
As much as your gut would tell you otherwise, it’s hard to conclude that there’s a significant editorial bias to Pitchfork’s reviews after looking at these numbers. The average score of 6.45 suggests that Pitchfork is quite discriminating in their reviews and hesitant to hand out high scores — something you’ve probably realized if you’re an avid reader of the site. Additionally, the numbers show no clear bias towards particular artists on a site-wide level (though we’ve seen Mr. Josephes’ KISS fetish), and no significant tendency to give a specific grade over any other.
Melatonin can function as an anti-depressant, according to some new research, by shifting circadian rhythms.
Lewy and his colleagues in the OHSU Sleep and Mood Disorders Lab set out to test the hypothesis that circadian physiological rhythms become misaligned with the sleep/wake cycle during the short days of winter, causing some people to become depressed. Usually these rhythms track to the later dawn in winter, resulting in a circadian phase delay with respect to sleep similar to what happens flying westward. Some people appear to be tracking to the earlier dusk of winter, causing a similar amount of misalignment but in the phase-advance direction. Symptom severity in SAD patients correlated with the misalignment in either direction.
The treatment of choice for most SAD patients is bright light exposure, which causes phase advances when scheduled in the morning. Because patients know when they are exposed to bright light, however, there is a considerable placebo response associated with it. Melatonin can also cause phase advances, but it has to be taken in the afternoon. The Lewy team used afternoon melatonin to test if it was more antidepressant than melatonin taken in the morning, which causes phase delays.
The researchers randomly assigned 68 SAD patients to one of three treatment groups, taking placebo capsules or melatonin in the morning or afternoon for three weeks. After four years of study, they concluded that, similar to persistent jet lag, circadian misalignment is a major part of SAD.
Most patients, typically phase-delayed types or "night owls," have misalignment that responded best to taking low-dose melatonin in the afternoon or evening. A longer-than-expected subgroup of SAD patients, phase-advanced types or "morning larks," responded best to taking low-dose melatonin in the morning. Melatonin did not cause drowsiness, because the doses used were lower than what is usually taken at bedtime.
Posted by Jon Rubin at May 2, 2006 06:34 PM
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