HEK 293 cells HEK 293 cells Human embryonic kidney 293 cells, also often referred to as HEK 293, HEK-293, 293 cells, or less precisely as HEK cells, are a specific cell line originally derived from human embryonic kidney cells grown in tissue culture. HEK 293 cells have been widely used in cell biology research for many years, because of their reliable growth and propensity for transfection. They are also used by the biotechnology industry to produce therapeutic proteins and viruses for gene therapy. HEK 293 cells were generated in 1973 by transfection of cultures of normal human embryonic kidney cells with sheared adenovirus
Language change may wonder how it was ever possible for a word meaning 'evil' to change its sense to 'wonderful' so quickly." All languages change continually, and do so in many and varied ways. Marcel Cohen details various types of language change under the overall headings of the external evolution and internal evolution of languages. The study of lexical changes forms the diachronic portion of the science of onomasiology. The ongoing influx of new words into the English language (for example) helps make it a rich field for investigation into language change, despite the difficulty of defining precisely and accurately the vocabulary