Abstract We aimed to evaluate the effect of red meat diet on gut microbiota in mice. Balb/c mice at weaning were randomized into control group and red meat groups with different proportions (25%, 50%, and 75%). Mice were fed with a standard pellet diet as control group, while those were fed with different proportions of red meat diet as red meat groups. After 8 weeks, they were sacrificed and their intestinal contents were obtained for 16S rRNA sequencing and bioinformatics analysis. Our results showed that there were significant-structural differences among the four groups. The top-two most abundant phylum were Firmicutes and Bacteroidetes. In the red meat groups, the abundance of Bacteroidetes was increased, but the abundance of Firmicutes was decreased. At the family level, Bacteroidaceae and Family XIII were significantly higher in the high-dose group than those in the control group. There were also significant differences in abundance of many genera. In conclusion, different proportions of red meat diet may lead to changes in gut microbial flora in mice. These changes may be pathological and may be related to the frequent occurrence of many diseases.

Cyanogen chloride, as a systemic toxic agent, can cause death rapidly. In this paper, a non-dispersive infrared sensor was designed for the infrared absorption detection of cyanogen chloride at 800 cm-1. The roughness of the internal coating material was analyzed by experiments, and the gold-plated gas chamber was selected. The light path propagation of different cross-section gas chambers was simulated, and the circular section gas chamber was selected to increase the infrared detector signal. The effect of flow rate on voltage was studied. The standard curve between voltage and concentration was obtained under the optimal condition of 0.4 L min-1. The maximum response time was 19 s, and RSD was less than 2%. The interference experiment results showed that common gases entering the gas chamber do not cause interference. The non-dispersive infrared sensor for cyanogen chloride has good stability and detects cyanogen chloride in real-time.