On June 30, 1908 a stunning explosion rocked the forest near the Tunguska river in Siberia. Estimates were that an asteroid exploded in the air a few kilometers above the earth's surface with a force 1,000 times that of the Hiroshima atomic bomb.

A new Sandia supercomputer simulations suggests that the asteroid that caused such a blast was much smaller than previously thought, bringing new concerns; there are more small asteroids than large ones.

“The asteroid that caused the extensive damage was much smaller than we had thought,” says Sandia principal investigator Mark Boslough of the impact that occurred June 30, 1908. “That such a small object can do this kind of destruction suggests that smaller asteroids are something to consider.

A genetic mutation expands lesions in the aorta and promotes coronary atherosclerosis, more commonly known as hardening of the arteries, according to a study by Yale School of Medicine in Cell Metabolism.

The researchers found that mice engineered without the Akt1 gene and fed a high cholesterol diet had many more signs of aortic atherosclerosis compared to their littermates. And, surprisingly, their coronary lesions were similar to humans, say the scientists.

“About 20 percent of the mice died spontaneously, perhaps due to an acute heart attack,” said William Sessa, senior author of the study, professor of pharmacology, and director of Yale’s vascular biology and therapeutics program.

What are the defining discoveries and great developments that are shaping the way we use materials and technologies today? Materials Today magazine has compiled a list of the top ten most significant advances in materials science over the last 50 years.

The top ten includes advances that have altered all our daily lives. Some have completely changed the research arena, and others have opened up new possibilities and capabilities. They are:

1. The International Technology Roadmap for Semiconductors
2. Scanning probe microscopes
3. Giant magnetoresistive effect
4. Semiconductor lasers and light-emitting diodes
5. National Nanotechnology Initiative
6. Carbon fiber reinforced plastics
7. Materials for Li ion batteries
8. Carbon nanotubes
9. Soft lithography
10.

Tiny copper structures with pores at both the nanometer and micron size scales could play a key role in the next generation of detonators used to improve the reliability, reduce the size and lower the cost of certain military munitions.

Developed by a team of scientists from the Georgia Tech Research Institute (GTRI) and the Indian Head Division of the Naval Surface Warfare Center, the highly-uniform copper structures will be incorporated into integrated circuits – then chemically converted to millimeter-diameter explosives.

Rajarshi Guha has yet again made a key contribution to our UsefulChem project by connecting us with Gus Rosania at the University of Michigan. Gus is interested in a fully open collaboration to help us further prioritize our drug targets based on predicted subcellular drug transport:

It is the first time I hear about Open Notebook Science, but it sounds like a fantastic idea! My research group studies the subcellular transport of small molecules.

Adult humans possess some mathematical abilities that are unmatched by any other member of the animal kingdom but there is increasing evidence that the ability to count sets of objects nonverbally is a capacity that humans share with other animal species.

In PLoS Biology, Elizabeth Brannon and Jessica Cantlon discuss how humans and nonhuman animals share a capacity for nonverbal arithmetic. The researchers tested monkeys and college students on a nonverbal arithmetic task in which they had to add the numerical values of two sets of dots together and choose a stimulus from two options that reflected the arithmetic sum of the two sets.

Monkeys perform addition like humans.

MIT scientists have found a way to induce cells to form parallel tube-like structures that could one day serve as tiny engineered blood vessels.

The researchers found that they can control the cells' development by growing them on a surface with nano-scale patterning. A paper on the work was posted in Advanced Materials.

Engineered blood vessels could one day be transplanted into tissues such as the kidneys, liver, heart or any other organs that require large amounts of vascular tissue, which moves nutrients, gases and waste to and from cells.

"We are very excited about this work,” said Robert Langer, MIT Institute Professor and an author of the paper.

Researchers at Oregon Health & Science University’s Neurological Sciences Institute have uncovered the system that tells the body when to perform one of its most basic defenses against the cold: shivering. Most interesting is that it's not the same sensory pathway as conscious cold detection.

Our bodies use two different but related sensory systems to conscious and subconsciously detect cold at the same time.

Shivering is one of the many automatic and subconscious regulatory body functions, often called homeostatic functions, that the brain regulates. Other examples include the adjustment of breathing rates, blood pressure, heart rate and weight regulation. Throughout the day, all of these important functions take place in the body without conscious thought.

Researchers stunned the world when they announced a cloaking device for the microwave range. This device made use of metamaterials that had a negative refractive index for electromagnetic radiation. The metamaterials were carefully designed split-ring resonators with a structure size much smaller than the wavelength. Only 10 stacked layers of metamaterials were necessary to achieve the desired invisibility effect.

Now, researchers from the group of Harald Giessen at the University of Stuttgart have succeeded in manufacturing a stacked split-ring metamaterial for the optical wavelength range (Na Liu et al., Nature Materials Jan. 2008 issue).

New research published today in the Journal of Cell Biology illuminates the mechanical factors that play a critical role in the differentiation and function of fibroblasts, connective tissue cells that play a role in wound healing and scar tissue formation.

When we are injured, the body launches a complex rescue operation. Specialized cells called fibroblasts lurking just beneath the surface of the skin jump into action, enter the provisional wound matrix (the clot) and start secreting collagen to close the wound as fast as possible. This matrix is initially soft and loaded with growth factors.

The fibroblasts "crawl" around the matrix, pulling and reorganizing the fibers.