Searching for Superhard Materials
July 11, 1998 | Volume 154 | Number 2
Cover: In computer models, carbon (red) and nitrogen (blue) atoms easily bond to form b -C3N4, a material predicted to rival the hardness of diamond. In real life, however, this superhard material has been super hard to makeprompting scientists to wonder whether it can exist at all. (Image: Michel Côté, U.C. Berkeley)
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News of the Week:
Parental Care Seen in Mountain Plants
Decaying debris of two species that flower once and then die provide vital moisture that helps seedlings survive.
Marijuana chemical tapped to fight strokes
Studies of rat neurons show that a compound in marijuana acts as an antioxidant and might protect against damage from strokes.
Explosive stripping of a material's surface
Intense, ultrashort laser pulses transform a thin layer at a solid's surface into a rapidly expanding, transparent fluid.
Cloned cows provide company for Dolly
The birth of two calves cloned from adult cells, reported in Japan, provides confirmation of the procedure that created the cloned sheep called Dolly.
Astronomers find long-period planet
A newly discovered planet orbiting a nearby star has the lengthiest orbit of any confirmed extrasolar planet and may be a promising candidate for direct imaging.
Ancient fire use flickers inside cave
A scientific team found no direct evidence of intentional burning in a Chinese cave widely regarded as exhibiting the oldest known example of the controlled use of fire.
Whats in ocean water? Shards of bacteria
The tattered remnants of bacteria constitute much of the dissolved organic matter in the open ocean.
Tiny icicles grow in electric fields
A strong electric field forces ice crystals to grow into long, sharp needles rather than snowflake patterns.
A brain area to count on
Discerning the larger of two numbers elicits electric activity in a specific part of the brain in both children and adults.
Traumatic rider to mental illness
Astronomers have discovered a new class of celestial objects, roughly one-third the temperature of the sun and less than one-tenth its mass.
Chickadees sneak up the social ladder
DNA tests of paternity in chickadees show the benefits of surreptitious partnering.
Looking for life in all the worst places
Researchers find complex microbial communities in one of the coldest spots on Earthinside the permanent ice on Antarctic lakes.
Plummeting falcons stay in control
New measurements help elucidate how gyrfalcons can plunge more than a quarter of a mile out of the sky without crashing.
AIDS vaccine trial gets go-ahead
The U.S. Food and Drug Administration has approved the first large test of a vaccine designed to prevent AIDS.
Gene therapy for arthritis works in rats
Transplanting DNA that encodes anti-inflammatory proteins combats arthritis in laboratory rats.
What was lifes first sunblock?
Tarlike polymers in the early oceans may have prevented ultraviolet light from destroying the first nucleic acids and amino acids.
Signs of unstable ice in Antarctica
The ice covering West Antarctica melted then reformed in the recent geologic past, raising concerns about its future stability.
Biological clocks sense light in obscure ways
New studies identify proteins that may help the human internal biological clock detect light.
As Hard as Diamond?
Tracking the elusive carbon nitride
Researchers are using a variety of techniques to identify and synthesize superhard materials.
Letters: A Selection from Letters to the Editor
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