The present invention provides di-substituted acetalanthraquinone-based compounds of the Formulae (l)-(IV) that are useful for cellular staining and for light-based detection of biological material, e.g. fluorescence-based detection of biological material. These compounds may be used in hydrolysed or non-hydrolysed form. Also provided is a fluorescent complex that comprises a nucleic acid and an acetalanthraquinone-based compound of the invention; and a method of staining a biological sample comprising cells or other biological material containing nucleic acid, which method comprises contacting the biological sample with an acetalanthraquinone-based compound of the invention. In the Formulae (l)-(IV), A and B are each independently of formula —R.sup.aCH.sub.2CH(OR.sup.b).sub.2; or one of A and B is of formula —R.sup.aCH.sub.2CH(OR.sup.b).sub.2 and the other one is of formula: —NR.sup.b.sub.2. ##STR00001##

The present invention provides di-substituted acetalanthraquinone-based compounds of the Formulae (l)-(IV) that are useful for cellular staining and for light-based detection of biological material, e.g. fluorescence-based detection of biological material. These compounds may be used in hydrolysed or non-hydrolysed form. Also provided is a fluorescent complex that comprises a nucleic acid and an acetalanthraquinone-based compound of the invention; and a method of staining a biological sample comprising cells or other biological material containing nucleic acid, which method comprises contacting the biological sample with an acetalanthraquinone-based compound of the invention. In the Formulae (l)-(IV), A and B are each independently of formula R.sup.aCH.sub.2CH(OR.sup.b).sub.2; or one of A and B is of formula R.sup.aCH.sub.2CH(OR.sup.b).sub.2 and the other one is of formula: NR.sup.b.sub.2.

##STR00001##

Electrowetting apparatus including at least one compound selected from the group consisting of: ##STR00001##
wherein each of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 is independently an alkyl group. In examples a fluid includes a dye compound selected from: ##STR00002##

An anthraquinone compound is provided. The anthraquinone compound has the following formula (I):

##STR00001## wherein one of R.sub.1, R.sub.2, and R.sub.3 is NH(CH.sub.2).sub.mCH.sub.3, and the other two are each independently selected from hydrogen or C.sub.1-4 alkyl group; and n and m are each independently an integer from 4 to 17.

An object of the present invention is to provide a thermal transfer recording sheet that enables images having a wide color gamut, a high chroma, and good lightfastness, in which the degree of catalytic fading is reduced, to be formed. The thermal transfer recording sheet includes a base material and a colorant layer on the base material. The colorant layer includes a yellow dye layer, a magenta dye layer, and a cyan dye layer. The dye layers each include, as a dye, a compound having a specific structure.