Interpretation of the development of neoadjuvant therapy for gastric cancer based on the vicissitudes of the NCCN guidelines

Gastric cancer is one of the most common digestive system tumors in China,and locally advanced gastric cancer(LAGC)accounts for a high proportion of newly diagnosed cases.Although surgery is the main treatment for gastric cancer,surgical excision alone cannot achieve satisfactory outcomes in LAGC patients.Neoadjuvant therapy(NAT)has gradually become the standard treatment for patients with LAGC,and this treatment can not only achieve tumor downstaging and improve surgical rate and the R0 resection rate,but it also significantly improves the long-term prognosis of patients.Peri/preoperative neoadjuvant chemotherapy and preoperative chemoradiotherapy are both recommended according to a large number of studies,and the regimens have also been evolved in the past decades.Since the NCCN guidelines for gastric cancer are one of the most authoritative evidence-based guidelines worldwide,here,we demonstrate the development course and major breakthroughs of NAT for gastric cancer based on the vicissitudes of the NCCN guidelines from 2007 to 2019,and also discuss the future of NAT.

Improvement of Impeller Blade Structure for Gas Injection Refining under Mechanical Stirring

Abstract： The impeller blade structure for gas injection refining under mechanical stirring has been explored by water model experiments. A sloped swept-back blade impeller is＇proposed for the purpose. The central part of the impeller is disk- or plate-shaped, and the blades are fitted to the side of the disk or plate. In addition, a disk is put on the top side of the impeller blades. The impeller can strengthen the radial and downward flow between the blades and weaken the swirl flow in the zone above the impeller. These effects on flow phenomena are favorable for disintegration and wide dispersion of bubbles which are injected from a nozzle attached to the center of the underside of the impeller. In addition, the sloped swept-back impeller requires less power consumption. The impeller shaft should be placed away from the vessel center so as to disperse the injected bubbles widely in the bath under mechanical stirring even with unidi- rectional impeller rotation and without installing baffles. The number of gas holes in the nozzle and the direction of gas injection have a little effect on the bubble disintegration and dispersion in the bath. Highly efficient gas injection refining can be established under the conditions of proper impeller size, larger nozzle immersion depth, larger eccen- tricity and rotation speed of the impeller. The sloped swept back blade impeller can decrease the power consumption and vet improve the bubble disintegration and wide dist^ersion in the bath.

Numerical simulation:preparation of La_2O_3 in a jet pyrolysis reactor

Based on the technique for preparing La Cl3 via direct pyrolysis of rare earth chloride solution, a jet pyrolysis reactor was designed and the intra-reactor temperature and chemical reactions were numerically simulated using computational fluid dynamics(CFD) technique.The results show that the flow rate variation at the fuel inlet does not largely affect the temperature in the reactor, while the increase in external pressure at the material inlet rapidly decreases the average temperature, Venturi temperature, and outlet temperature. The CH4 and O2inside the reactor are combusted completely, and when the material inlet pressure is \90 Pa, the La Cl3 is fully pyrogenated. The contents of CO2, La2O3, and HCl fluctuate near the Venturi tube and finally stabilize. La2O3 content at the outlet is in a top-to-bottom gradient.