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Background: Currently, the mechanisms of impaired gut mucosal immunity in sepsis remain unclear. Gut immunoglobulin A (IgA) is an important defense mechanism against invasive pathogens, and CD4+ T cells regulate the IgA response. Aim: We aimed to verify the hypothesis indicating that CD4+ T pyroptosis induced by lipopolysaccharide (LPS) leads to an impaired gut IgA response and subsequent bacterial translocation and organ damage. Methods: Cultured CD4+ T cells and mice were manipulated with LPS, and pyroptosis was improved by A438079 or adoptive CD4+ T cell transfer. The changes demonstrated in pyroptosis-related molecules, cytotoxicity and CD4+ T cells were examined to determine CD4+ T pyroptosis. The changes demonstrated in IgA+ B cells, AID (key enzyme for immunoglobulins) and IgA production and function were examined to evaluate the IgA response. Serum biomarkers, bacterial colonies and survival analysis were detected for bacterial translocation and organ damage. Results: LPS attack induced CD4+ T pyroptosis, as evidenced by increased expression of P2X7, Caspase-11 and cleaved GSDMD, which elevated cytotoxicity and decreased CD4+ T cells. Decreased CD4+ T subsets (Foxp3+ T and Tfh cells) influenced the IgA response, as evidenced by lower AID expression, which decreased IgA+ B cells and IgA production and function. A438079 or cell transfer improved the IgA response but failed to reduce the translocation of gut pathogens, damage to the liver and kidney, and mortality of mice. Conclusion: LPS attack results in CD4+ T pyroptosis. Improvement of pyroptosis restores the mucosal IgA response but fails to ameliorate bacterial translocation and organ damage. [ABSTRACT FROM AUTHOR]

With the further development of food processing industry，food quality and safety have been paid more and more attention by the public.In order to protect food quality and extend the shelf life，it is of great significance to develop new packaging materials.In this paper，four types of new packaging materials were introduced，including antibacterial materials，air-conditioned materials，controlled-release materials and intelligent materials.The characteristics of various packaging materials and their research progress in the field of food packaging have been summarized.Moreover，the development trend of food packaging materials has been prospected.

BACKGROUND The identification of natural and synthetic amethyst is still a challenge for gemological laboratories either at home or abroad. Previous studies focus on twinning, color band, inclusions and the infrared spectrum. Controversy still exists on whether the 3595cm-1 and 3543cm-1 absorptions are indicative or conclusive clues when employing infrared spectroscopy to separate natural amethyst from synthetics. OBJECTIVES To characterize the features of natural and synthetic amethyst. METHODS Typical natural and synthetic amethyst samples were collected. The limitations of infrared spectroscopy to identify natural and synthetic amethyst were studied. The polarized Raman spectroscopy was applied to the identification of amethyst genesis. RESULTS The results showed that there were some limitations in the origin determination of amethyst by using the infrared absorption peaks of 3595cm-1 and 3543cm-1 as criteria. These peaks were indicative, but cannot be used as a decisive basis. The polarized Raman spectrum was complementary to infrared spectroscopy. The polarized Raman spectrum (the direction of both incident laser and Raman signal set as horizon-HH) peak of 400cm-1 were observed in all the natural amethyst, but this peak was absent in the synthetics. The polarized Raman spectrum (direction:HH) peaks of 795cm-1 and 448cm-1 appeared in all the synthetic amethyst, but were not detected in natural amethyst. CONCLUSIONS The difference of polarized Raman spectra may be related to different degree of crystal lattice deformation in natural and synthetic amethyst. The polarized Raman peaks of 400cm-1, 448cm-1 and 795cm-1 can be used as a new criterion for source determination of amethyst.