DEVELOPING AND DESIGNING NEW CHEMICALS AND MATERIALS - Chemistry: Notable Research and Discoveries - page 25

The initial algorithm suggests possibilities, but Fischer and his col-
leagues went a little further. They wrote a second algorithm using the
principles of quantum mechanics to probe the list of possibilities. By
calculating how stable each of the structures might be, this second step
identified the most stable structures in terms of energy—these are the
ones most likely to occur, for unstable structures tend to evolve into more
stable structures. (This is similar to the process of a ball rolling down-
hill, coming to rest at the lowest state.) As described in the 2006 paper
“Predicting Crystal Structure by Merging Data Mining with Quantum
Mechanics,” published in Nature Materials, the researchers succeeded in
90 percent of tests in narrowing down the correct structure to a short list
of five possibilities. This five was out of thousands of candidates.
Having algorithms that can predict structures of new or unknown
materials gives engineers a better chance of selecting the best material
for the job. At this early stage of research, it is not clear how success-
ful materials design can be, or which methodology is better. Perhaps
the best technique will employ a range of strategies, as Fischer and his
colleagues did by combining data mining with quantum mechanical
computations.
New materials for superior computer data storage and other elec-
tromagnetic applications often involve alloys, as in the example above.
But design strategies also apply to other difficult problems, including
the development of new and improved drugs to treat patients.
HITTIngTHETArgET—dISCovErIng
AnddESIgnIngnEWMEdICATIonS
Average life expectancy for Americans jumped from 45 to 50 years in
1900 to almost 80 in the early part of this century. One of the major rea-
sons for the increased longevity was the development of effective anti-
biotics. Antibiotics are drugs that kill microorganisms but do not affect
human cells, so they help the body fend off bacterial and fungal infec-
tions. The early part of the 20th century saw the rise of antibiotics such
as penicillin and sulfonamide compounds, decreasing fatalities from
wound infections and other diseases caused by bacteria or fungi. Many
kinds of antibiotic can be found in the modern physician's arsenal.