Abstract: A method of preparing fluorescent material containing carbon quantum dots, comprising milling a metal in the presence of carbon dioxide in a sealed container for a set duration to form the carbon quantum dots containing material. The carbon dioxide is preferably obtained as a waste gas from a human related activity such as an industrial process and may be provided in the form of dry ice.

Abstract: A method of preparing fluorescent material containing carbon quantum dots, comprising milling a metal in the presence of carbon dioxide in a sealed container for a set duration to form the carbon quantum dots containing material. The carbon dioxide is preferably obtained as a waste gas from a human related activity such as an industrial process and may be provided in the form of dry ice.

Abstract: Compounds of formula (I), ##STR1## wherein R.sup.1 represents C.sub.1-4 alkyl; and R.sup.2, R.sup.3, R.sup.4 and R.sup.5 each independently represent hydrogen, halogen, C.sub.1-4 alkyl, C.sub.1-4 alkoxy, C.sub.1-4 alkoxyC.sub.1-4 alkyl, C.sub.1-4 alkylsulphonyl, trifluoromethylsulphonyl; optionally substituted arylsulphonyl, optionally substituted heteroarylsulphonyl, optionally substituted aralkylsulphonyl, optionally substituted heteroaralkylsulphonyl, nitro, cyano, amino, mono- or di-alkylamino, trifluoromethyl, trifluoromethoxy, hydroxyl, hydroxyalkyl, C.sub.1-4 alkylthio, C.sub.1-4 alkanoyl, C.sub.1-4 alkoxycarbonyl, aminosulphonyl, alkylaminosulphonyl or dialkylaminosulphonyl; or R.sup.1 and R.sup.2 together form a linking chain-(CH.sub.2).sub.m Op (wherein m is 2 to 4 and p is zero or 1) which chain may be optionally substituted by one or two C.sub.1-4 alkyl groups; and Y represents a group selected from (a) or (b) wherein R.sup.6 and R.sup.7 independently represent hydrogen, C.sub.