Methods for purifying fucoidan in extracts from brown seaweed are disclosed. The signal sampling circuit has a signal-generating module, a sample and hold module, and a differential module. Therefore, a liquid crystal display device having a wide viewing angle is realized in which a contrast ratio is improved by suppressing a light leakage occurring when observed from an oblique direction. The mobile router 525 provides a network interface between one or more local subnets 530, 535 and the at least one cellular network 505, 510. 5 KW and 30 W in an image forming state and in a standby state, respectively, wherein the toner is the toner mentioned above.