Abstract: The present invention discloses a DNA vaccine and its method of preparation, which employs DNA recombination technique to co-incorporate a fragment of tumor-associated gene and a fragment of cytokine gene into a vector. The administration of such DNA vaccine may enhance the immune response of the host through the co-expression of tumor-associated antigen and cytokine, and thereby achieve the therapeutic effect of inhibiting or retarding tumor growth.

Abstract: A hollow screw cooling device, which has a set of apertures provided on an oil-proof base on the driven end of the hollow screw. By having fixing screws go through the apertures and the through holes on the bearing press board and fixed on the bearing base, the oil-proof base can be fixed on the outer side of the bearing press board. By directly taking off fixing screws, the oil-proof base can be directly taken off the bearing base when maintaining or replacing the seal without disassembling the components such as the bearing and bearing device.