Abstract: A printhead device is provided. The printhead device includes a cell tube, a cell tube rubber plug covering the cell tube, a connector arranged at an end of the cell tube, and a fixing knob fixed to the connector and communicating with a printing nozzle through a bottom liquid tube. A fixing clip is provided on the upper part of the cell tube, and a stepping motor box is provided on the upper end of the fixing clip. An air valve box is arranged on the upper side of the stepping motor box, and a rotary air valve is provided in the air valve box. The rotary air valve communicates with the inner cavity of the cell tube through an internal vent tube, and with an air valve straight tube or an air valve gooseneck tube.

Abstract: Volatile organic compounds emitted from gastric cancer cell metabolite is separated and detected using HS-SPME/GC-MS. A volatile compounds fingerprint atlas-spectrum model are disclosed for early gastric cancer diagnosis/warning Volatiles 3-octanone and 2-butanone as indicators of gastric cancer cells which are not contained in the headspace of gastric mucosal cells GES-1. Meanwhile, the ratio of mass to volume to concentration of 4-isopropoxy alcohol, nonanoic acid, and 4-butoxy n-butanol is as follows: 4-isopropoxy alcohol [gastric cancer cells]/[normal gastric mucosa cells]?0.31; nonanoic acid [gastric cancer cells]/[normal gastric mucosa cells]?0.36; and 4-butoxy n-butanol [gastric cancer cells]/[normal gastric mucosa cells]?0.40. The volatile organic compound in cell metabolite to be detected is compared with the fingerprint atlas-spectrum model, so as to implement screening and warning of the early gastric cancer.