Abstract: A fan is enclosed in the enclosure of an electronic apparatus. The fan discharges air out of a ventilation opening of the fan itself. Heat radiating fins are located in an air passage extending from the ventilation opening. A dust catcher is removably mounted in an opening of the enclosure from the outside of the enclosure. The dust catcher is located in the air passage between the heat radiating fins and the ventilation opening. The dust catcher serves to catch the dust in the air passage. The dust catcher is removed from the enclosure along with the dust. The dust is thus reliably cleared from the air passage. The dust catcher can then be cleaned. The cleaned dust catcher can again be set in the opening of the enclosure. Airflow of a sufficient amount is in this manner always kept in the air passage.

Abstract: Xanthene compounds represented by the formula: wherein R1 is a carboxyl group which may be esterified or amidated; R2 is a hydrogen atom, a hydroxyl group, or a hydrocarbon group which may be substituted; R3 and R4 are the same or different and are a hydroxyl group which may be substituted; R5 and R6 are a hydrogen atom or a halogen atom; R7 is a hydrogen atom, a nitro group, a halogen atom, a hydrocarbon group which may be substituted, a heterocyclic group which may be substituted, or an acyl group which may be substituted; n is an integer of 0 to 2; and Y is an oxygen atom or two hydrogen atoms; and when n is 0, R2 may be a group represented by the formula: wherein the symbols have the same meanings as defined above, or a salt thereof inhibit a binding of B7-1 to CD28, prevent the B7-1-dependent activation of T cells and inhibit IL-2 production from T cells, thus being used as an immunomodulator such as a graft rejection inhibitor or a pharmaceutical composition for thera