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Archive for April, 2011
Bacteria Survive & Reproduce in Gravity 400,000X Stronger Than Earth's
E. coli
What’s the News: Some bacteria can live in extreme “hypergravity,” found a new study published in the Proceedings of the National Academy of Sciences, surviving and reproducing in forces 400,000 times greater than what’s felt on Earth. These findings fit with the idea that microbes carried on meteorites or other debris—a ride that would have subjected them to hypergravity-strength forces—may be the ancestors of life on Earth.
Materials Scientists' Solar Cell Has a Virus—and That's a Good Thing
What’s the News: In traditional solar cells, sunlight is absorbed by the cell (made from silicon or titanium dioxide), freeing electrons, which travel across the cell to an electron collector, or electrode. A problem with solar cells is that many electrons don’t find their way to the electrode; carbon nanotubes can be used as bridges between the loosened electrons and the electrode, but nanotubes tend to bunch up, decreasing the efficiency and causing short circuits. Researchers have now created genetically engineered viruses can be used to keep the nanotubes in place, increasing energy conversion by nearly one-third. “A little biology goes a long way,” research group leader Angela Belcher told MIT News, noting that the entire virus-nanotube bridging layer represents only 0.1% of the finished cell’s weight.
After a Nice Hot Blood Lunch, Mosquitoes Go Into Shock
What’s the News: When mosquitoes finish a piping-hot meal of blood, they have more than your average postprandial snooze, biologists have found: they go into heat shock, producing proteins most organisms only make when something is terribly wrong.
New Laser Igniter Might Be Beginning of the End for Classic Spark Plug
What’s the News: Scientists have developed a laser that’s small and tough enough to work in the combustion engine of a vehicle yet powerful enough to ignite the fuel-air mixture that drives combustion cylinders. The researchers say that laser-ignited combustion engines could be more fuel efficient than traditional spark-plug ones: Unlike spark plugs, which transmit their sparks in milliseconds, lasers transmit energy within nanoseconds. Inventor Takunori Taira says that “timing—quick combustion—is very important. The more precise the timing, the more efficient the combustion and the better the fuel economy.”
What Makes a Queen Bee? One Special Protein, Apparently
Queen bee larvae floating in royal jelly
What’s the News: It’s long been known that a female bee’s place in the social order—whether she becomes a worker or a queen—depends not on her genes, but on whether she eats royal jelly. A study published in Nature found that royalactin, a protein found in royal jelly, is responsible for many of the physical differences that distinguish queens from the hoi polloi of the hive—and, surprisingly, that royalactin can even cause fruit flies to develop queen bee-like traits. This finding also shines light on how, at a cellular level, royal jelly turns bees into queens.
Could Bacteria Communicate by Bouncing Electrons Around Their Chromosomes?
What’s the News: A group of physicists say they’ve found a way to account for the mysterious radio signals that may be emanating from colonies of E. coli—and it’s not because they’re trying to get our attention.
Tube-Shaped Scaffold May Help Nerve Cells Connect to Prosthetics
What’s the News: Engineers and patients dream of mechanical prosthetic limbs that can talk and listen to the brain, moving in response to thought and sending back sensory information. For that dream to become reality, electrodes from the prosthetic have to connect with nearby nerve cells—a tricky proposition, given that nerve cells in an amputated limb won’t grow without proper structural support. A new tubular scaffold, described in detail by Technology Review, has tiny grooves that fit bundles of nerve cells, which could provide the support nerves need to interface with a mechanical limb better than current designs.
Visual Virtual People: A Better Model for the Behavior of Crowds
A new model of crowd behavior uses simple visual rules.
What’s the News: When crowds go wrong, they go really wrong—more than 300 people died in a stampede in Cambodia last year during a festival, and hundreds more have been crushed to death in periodic disasters near the Muslim holy city of Mecca. A major flaw of computational models describing how people behave in crowds is that they are often too simplistic or too specific to a situation to explain both normal and disastrous behavior. A new model manages to recreate both types of behavior, working from two basic visual rules: (1) each person will move in the least crowded direction in their line of sight, and (2) they will adjust their speed to maintain a safe distance from visible obstacles.
“This work is an extremely important step in pulling together our fragmented understanding,” says behavioral biologist Iain Couzin, who was not involved in the study (via ScienceNOW). “We’re now approaching a sort of unified understanding of human behavior in crowds.”
Massive Martian Dry-Ice Deposit May Explain How Planet Used to Have Watery Surface
What’s the News: If you were to bring a glass of water to Mars, the liquid would instantly boil because the Red Planet’s carbon dioxide atmosphere is so thin: The vapor pressure of the water easily surpasses the weak atmospheric pressure, sending water molecules flying off quickly into the atmosphere. However, ancient shorelines and river-like features indicate that Mars had a watery past, leading researchers to wonder what happened to Mars’ once-thicker atmosphere. Now, data from the Mars Reconnaissance Orbiter has uncovered a massive deposit of solid CO2 at the south pole that could double the planet’s atmospheric pressure if it were released as gas. “If you double the amount of CO2 in the atmosphere, it’s quite possible that you could have liquid water,” planetary scientist Philip James of the Space Science Institute in Boulder told Scientific American. “People have suggested that this could happen, and now it looks like it could be possible.”
Do Low-Carb Diets During Pregnancy Lead to Fatter Kids?
What’s the News: Researchers have known for decades that what a woman eats during her pregnancy can impact her child’s weight later in life. Now, a new study shows a possible mechanism for how mom’s diet affects baby’s weight: Epigenetic changes—changes that can increase or decrease the expression of a particular gene but don’t alter the genetic sequence—to a gene involved in fat metabolism can be passed from mother to child during pregnancy.
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