Investigation and case analysis of an occupational chronic benzene poisoning accident / 中华劳动卫生职业病杂志

This article investigated an occupational chronic benzene poisoning incident that occurred in a sealing material factory in Hebei Province in September 2019, analyzed the clinical data of workers, to explore the causes of occupational chronic benzene poisoning, and summarize the diagnosis and treatment characteristics and treatment outcome. According to GBZ 68-2013 "Diagnosis of Occupational Benzene Poisoning", a total of 12 cases of occupational chronic benzene poisoning were diagnosed among the 20 workers, including 2 cases of occupational chronic mild benzene poisoning, 7 cases of moderate benzene poisoning, and 3 cases of severe benzene poisoning. Both mild and moderate poisoning patients had recovered after treatment. Severely poisoned patients had recovered more slowly, and the white blood cell count was still 2.0×10(9)-3.0×10(9)/L during the 1-year follow-up. This benzene poisoning incident was caused by illegal operations. The responsibility of the employer, the supervision of the administrative agency, and the awareness of personal protection of employees should be strengthened to avoid or reduce the occurrence of poisoning incidents and ensure the health of workers.

Optimal Model Design for High Production of Phenazine-1-Caboxylic Acid (PCA) by Pseudomas. spp M18G / 中国生物工程杂志

Phenazine-1-carboxylic acid(PCA)is one of the major antifungal compounds produced by plant growth-promoting rhizosphere(PGPR)pseudomonads and has been shown to contribute to the biological control of soil-borne plant pathogens.Model on secondary metabolite phenazine-1-carboxylic acid(PCA)fermentation nutrition conditions of gacA inactivate mutant Pseudomonas sp.M18G was constructed by Plackett-Burman design(PB)and Response Surface Method(RSM).In PB design four key components selected from 12 different factors have shown to play an important role for promoting PCA production.Center Composite Design(CCD)was adopted to establish a fermentation model for the four nutrition components using RSM.The optimal concentration of the four components based on analysis of regression equation were determined that soybean meal 33.4 g/L,glucose 12.7 g/L,soy peptone10.9 g/L,ethanol13.8 g/L,and the highest PCA production could reached 1.89 g/L after 60h fermentation and the yield increased to 6 fold over that before optimization.The contour graphs depicted interactions of the two nutrition components showed that soybean meal and ethanol played an even more crucial role for the highest production of PCA in fermentation.It establishes a method for high PCA production and lays a foundation for the further PCA commercial development.