Abstract: A method of culturing avian cells in a medium with a pH value of 7.8 or above, whereby avian cells can be subcultured stably for long. Since avian cells have been incapable of subculture heretofore, it has been impossible to effect in vitro cell or gene manipulation therewith. Now that such a manipulation becomes possible by the invention method, the way is opened for the industrial utilization of avian cells in the creation of transgenic birds and the production of vaccines.

Abstract: The negative-working photosensitive composition of the invention, which is suitable as a photoresist material in the photolithographic processing of semiconductor devices, comprises (a) a condensation product of a hydroxy-substituted diphenylamine compound such as 4-hydroxy diphenylamine and a methylol melamine or alkoxylated methylol melamine by the reaction in a medium of phosphoric or sulfuric acid and (b) an azide compound capable of strongly absorbing UV or far UV light. The composition gives a photoresist layer having high resistance against heat in the post-baking and the attack of gas plasma encountered in the dry etching for semiconductor processing.

Abstract: The invention provides an aqueous alkaline developer solution for a positive-type photoresist layer for pattern-wise treatment of the surface of a substrate, e.g., semiconductor wafer. The developer solution contains a tetraalkyl ammonium hydroxide, e.g., tetramethyl ammonium hydroxide, and a trialkyl hydroxyalkyl ammonium hydroxide, e.g., trimethyl hydroxyethyl ammonium hydroxide, as the essential ingredients and the temperature dependency of the development performance thereof is noticeably smaller than that of conventional developer solutions with respect to properties of the sensitivity of the photoresist and the thickness reduction of the photoresist layer in the unexposed areas, by virtue of the compensating temperature dependencies for these properties of these two ingredients for each other.