Seniors and Depression: The difference between depression and dementia. Depression is a mood disorder; dementias like Alzheimerâs disease, can have similar symptoms but they are different illnesses and have different treatment plans.
From a synthesis standpoint, nanotechnologies can be classified as variations of bottom-up technologies, such as self-assembly, or top-down technologies, such as lithographic methods (Box 1). Many nanotechnologies combine aspects of both strategies.
For more on the history of the nanotechnology concept, see: Nanotechnology: from Feynman to the Grand Challenge of Molecular Manufacturing, by C. Peterson in IEEE Technology and Society, Winter 2004. PDF [2.5 MB].  Molecular Nanotechnology: the Next Industrial Revolution , by C. Peterson in IEEE Computer, January 2000.