there is probably no need for extensive exploration to believe that movable type invention had a tremendous and historical impact on expansion of science and emergence of renaissance in europe, as tens of articles and research books have already been dedicated to this fact; but the real question which requires historical explanation is how the man before invention of printing had preserved his ...

inorganic lead compounds are used most widely in paint and pigment industries. because of exposure to lead dust in workers in a copying center, we compared blood lead levels in these workers to normal individuals and investigated the relationship between job tenures of the workers and their blood lead levels. this survey was performed on 20 simple workers in a copying center of tehran universit...