13 January 2011 early pm

Sleep: evidently the light you are in prior to sleeping and while sleeping has an effect:

Melatonin is a hormone produced at night by the pineal gland in the brain. In addition to its role in regulating the sleep-wake cycle, melatonin has been shown to lower blood pressure and body temperature and has also been explored as a treatment option for insomnia, hypertension and cancer. In modern society, people are routinely exposed to electrical lighting during evening hours to partake in work, recreational and social activities. This study sought to understand whether exposure to room light in the late evening may inhibit melatonin production.

“On a daily basis, millions of people choose to keep the lights on prior to bedtime and during the usual hours of sleep,” said Joshua Gooley, PhD, of Brigham and Women’s Hospital and Harvard Medical School in Boston, Mass. and lead author of the study. “Our study shows that this exposure to indoor light has a strong suppressive effect on the hormone melatonin. This could, in turn, have effects on sleep quality and the body’s ability to regulate body temperature, blood pressure and glucose levels.”

In this study, researchers evaluated 116 healthy volunteers aged 18-30 years who were exposed to room light or dim light in the eight hours preceding bedtime for five consecutive days. An intravenous catheter was inserted into the forearms of study participants for continuous collection of blood plasma every 30-60 minutes for melatonin measurements. Results showed exposure to room light before bedtime shortened melatonin duration by about 90 minutes when compared to dim light exposure. Furthermore, exposure to room light during the usual hours of sleep suppressed melatonin by greater than 50 percent.

So, here is a rookie question: are they talking about eye exposure or skin exposure?

Mollusks: can develop teeth strong enough to crush rock. How?

Derk Joester of Northwestern University is studying how the chiton makes its teeth. Chitons are mollusks. They’re small, rather flat and oval in shape. The chiton Joester studies is called Chaetopleura apiculata, and it has a rather odd way of getting a meal.

“This particular organism literally chews rock in order to feed,” he says. It grinds down rock to get at algae and other food particles that might be sandwiched in the rock. “And for that, it needs incredibly tough and hard teeth.”

In fact, Joester says chiton teeth are one of the hardest and toughest materials known in nature. “They also have a very particular structure that allows them to self-sharpen to a certain degree. … Imagine a knife that keeps its edge forever.”

And that’s a trick Joester would like to be able to replicate in the lab.

A Closer Look

But before you can contemplate making such a thing in the lab, you need to know how the chiton does it. “For that, we are using one of the most powerful microscopes, the so-called atom probe,” Joester says.

He focuses this microscope on the interface between the soft organic molecules of the chiton’s innards with the rock-hard inorganic minerals of the chiton’s teeth. [...]

When materials scientists try to make things in the lab, they frequently have to resort to high temperatures and extreme pressures to force materials into a useful shape. And yet the chiton is able to make its remarkable teeth in regular old seawater and without special equipment. That’s why it’s worth studying.

“We can start to understand what the important design features are, and then start to develop techniques in the lab that might be able to take some of those features out and replicate them,” Estroff says.

Millions of years of evolution did what we currently cannot do!

Politics Evidently conservatives are fine with their own superstitions, but not the superstitions of others. Some were unhappy with the Native American prayers at the recent Arizona memorial service.

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