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Background: Intraamniotic infection is associated with an increased risk of multiple adverse outcomes in offspring, especially neonatal necrotizing enterocolitis (NEC), which is one of the serious gastrointestinal diseases in neonates. However, the underlying mechanism remains undefined. We hypothesize that bacterial endotoxin-induced maternal inflammation causes intestinal injury in offspring, thereby affecting the composition of the intestinal microbiome. Methods: Pregnant Sprague Dawley rats were received intraperitoneal injections with 700 μg/kg lipopolysaccharide (LPS, which was the same as bacterial endotoxin) or saline at 15 days of gestation. Pups were allowed to deliver naturally and euthanized at days 0, 3 and 7 after birth. Intestinal tissue and feces samples from offspring were collected to evaluate the effects of maternal inflammation on intestinal flora colonization and intestinal mucosal development. Results: Significant intestinal injury of the offspring induced by prenatal LPS exposure was observed on day 0 and 3 after birth. In addition, prenatal LPS exposure also induced significant changes in the intestinal microbiome of the offspring with a significant increase in Proteobacteria (Escherichia-Shigella) and a decrease in Firmicutes at 7 days after birth. Conclusions: Thus, our findings suggest that LPS-induced maternal inflammation induces intestinal injury in offspring and subsequently leads to NEC-like changes in the composition of the intestinal microbiome. [ABSTRACT FROM AUTHOR]

In this paper, AZ31 magnesium alloy is cast by applying the semi-continuous casting process with a low-frequency electromagnetic field. By studying the influence of electromagnetic field frequency, excitation current intensity and casting velocity on the microstructure and mechanical properties, the optimum process under oil-slip electromagnetic casting conditions was determined to improve the degree of grain refinement, yield strength, elongation and tensile strength of AZ31 alloy. An improved microstructure refining effect and higher hardness can be obtained with a current intensity af 60 A. The microstructures and mechanical properties obtained for different casting velocities of V = 200 mm/min and V = 230 mm/min at processing parameters of f = 30 Hz and I = 120 A were compared. Our results suggest that a higher casting speed does not lead to grain refinement or improved mechanical properties. Frequency [ABSTRACT FROM AUTHOR]