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Quorum Sensing

What a fantastic phrase.

According to Wikipedia:

Bacteria that use quorum sensing constitutively produce and secrete certain signaling molecules (called autoinducers or pheromones). These bacteria also have a receptor that can specifically detect the signaling molecule (inducer). When the inducer binds the receptor, it activates transcription of certain genes, including those for inducer synthesis. There is a low likelihood of a bacterium detecting its own secreted inducer. Thus, in order for gene transcription to be activated, the cell must encounter signaling molecules secreted by other cells in its environment. When only a few other bacteria of the same kind are in the vicinity, diffusion reduces the concentration of the inducer in the surrounding medium to almost zero, so the bacteria produce little inducer. However, as the population grows, the concentration of the inducer passes a threshold, causing more inducer to be synthesized. This forms a positive feedback loop, and the receptor becomes fully activated. Activation of the receptor induces the up-regulation of other specific genes, causing all of the cells to begin transcription at approximately the same time. This coordinated behavior of bacterial cells can be useful in a variety of situations. For instance, the bioluminescent luciferase produced by Vibrio fischeri would not be visible if it were produced by a single cell. By using quorum sensing to limit the production of luciferase to situations when cell populations are large, V. fischeri cells are able to avoid wasting energy on the production of useless product.

They're studying ways to disrupt quorum sensing in order to fight drug-resistant bacteria.

Taking this a step further, the research community could use the information about the intercellular network to identify the best approaches to quorum-sensing inhibition, which disrupts bacterial communication even if it does not actually kill the bacteria. "Once we have modeled their communications network, we can look at how bacteria behave under attack, how they communicate and how this communication breaks down," Marculescu says. "Longer-term, with detailed [information] about a patient's condition, our framework can intelligently generate personalized treatment plans that have the best predicted efficacy without inducing drug resistance."

I cringed a little reading this because the scientists use Twitter analogies to explain how bacteria communicate. I'm old now and i mistrust Twitter on an instinctual level. Also, when they talked about disrupting those avenues of communication in order to defeat the bacteria from organizing, i sort of imagined it in terms of the government using techniques to thwart activism. But "quorum sensing" is still pretty awesome.

By min | August 31, 2015, 9:30 AM | Good Words & Science | Comments (0)| Link

Solar Sails in the Works


Just as sailboats use wind pressure to propel through water, solar sails use the pressure from light radiated by the sun to move through space. Once the province of science fiction authors such as Arthur C. Clarke, solar sailing is gradually moving into the realm of reality. A privately funded $4.5-million mission to test solar sailing technology called LightSail now has a launch date in April 2016 and a ride to space onboard SpaceX's Falcon Heavy rocket. Once in orbit, LightSail 1 will make maneuvers using sunlight, rather than rocket fuel.
LightSail 1 will deploy four ultrathin Mylar sails that will stretch to 32 square meters (potentially large enough for naked-eye observers to spot from the ground). These sails will be bombarded with sunlight and each light particle, or photon, that impacts them will impart a tiny bit of momentum. Added up, those tiny bits should be enough to move the spacecraft without the need for heavy and expensive chemical propellant. If LightSail's orbital speed increases once it deploys its sail, engineers will know it works. In theory, solar sailing should be powerful enough to propel a spacecraft out of Earth orbit and into the solar system. "The disadvantage to that is it takes a long time [to move], just like it takes a lot longer to sail to the Bahamas than drive a speedboat," Stetson says. Still, in space beyond Earth's atmosphere without friction to stop it, once a solar sail gets going, it keeps accelerating as long as sunlight keeps hitting it. That makes solar sails an appealing option to explore the whole of the solar system and beyond. Many experts say they're the likeliest candidate to propel the first interstellar mission to another star, with extra thrust supplied by a laser, perhaps stationed in orbit around the sun, aimed at the sail in addition to sunlight. One downside, however, is that solar sails don't come with brakes or any means of changing trajectory or slowing down once they're zooming. One possible solution is using a planet or star's gravity to decelerate the craft or slingshot it along a desired path.

Don't slingshot into the past!

Forget space travel. Where's my solar sail car?

By min | August 27, 2015, 3:13 PM | Science | Comments (0)| Link

Smartphone for Daredevil

A tiny startup outside Chicago has created external hardware for a smartphone that enables a user to feel as well as see an image on flat glass. The user has the sensation of touching keys on a keyboard, for example.
The technology works by tricking the brain into feeling something that doesn't exist, not unlike the way a television fools the eye into perceiving motion. A tiny actuator in the housing makes the glass resonate at 38.7 kilohertz, an ultrasonic frequency that cannot be heard or felt. Tanvas's algorithms analyze images on the Moto G's screen, and the phone calculates where over the screen the user's finger is positioned. These data are translated into ultrasonic oscillations that create the illusion of something physical.
The TPad is capable of simulating smooth and raised shapes, abrupt edges and curved lines. Bas-relief images on, say, a coin can be faithfully represented. A scanned page's words and images might be made to feel as if they were on a raised surface.


So, i like being able to write my notes, as opposed to Swyping them (takes forever. damn you, autocorrect!). But using a stylus on a tablet or phone is horrible. No friction. Mebbe this would fix that. And then mebbe our signatures when we sign for packages won't look so stupid.

By min | August 20, 2015, 1:44 PM | Comics & Science | Comments (0)| Link

More Sleep Can Hold Off the Decay

According to the British Sleep Council, if you don't sleep for at least six hours a night, you're 12% more likely to die young. Lack of sleep can trigger a range of health problems. It can give you heart disease. It can give you diabetes. It can make you obese. It can ruin your concentration, your memory and your youthful good looks in one fell swoop.
The problem is now so bad that the government has actually had to intervene on our behalf. The middle-aged will soon be targeted with a campaign designed specifically to make them go back to bed. The most chilling line in Public Health England's description of its own campaign is this: "Only around 20% to 30% of what we think of as 'ageing' is biological; the rest is 'decay' or 'deterioration', which can be actively managed or prevented." Essentially, if you're aged between 40 and 60 and you don't get enough sleep, you're rotting your own body.


Hey, i will go to sleep right now if you let me. I love sleeping. I just hate going to bed, which is an important distinction. But once i'm asleep, i will happily stay that way for many, many hours, so the six hour minimum is no problem for me. I'm also lucky in that i don't have kids to disrupt my sleep schedule, i don't have crazy work hours, and i don't have a sleep disorder. I dunno what the rest of you people are doing. Bed is lovely.

This amused me:

Since we had a baby earlier this year, I've physically aged by about three decades. I've somehow managed to become both sunken and paunchy, the vast majority of my sentences now begin with the word "Nyuhh" and it takes a superhuman level of effort to pay attention to anything, which is why I just had to take a 15-minute break from this sentence to look at photos of watermelons on the internet.

By min | August 13, 2015, 2:16 PM | Science | Comments (0)| Link

That's... oh wait. That *is* a moon.

Cool animated photo of the moon orbiting the Earth from NASA.

By fnord12 | August 6, 2015, 8:52 PM | Science | Comments (1)| Link

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