Sentence:  For the albumin method , equal volumes of 30 % bovine albumin , sample and 2 % cells suspended in saline were allowed to stand at room temperature for 1 hr and <WSD>then</WSD> were centrifuged at 1000 rpm for 1 min . 
Meaning of the word marked with <WSD> tags:  subsequently or soon afterward (often used as sentence connectors)