Background: Alterations in the microbiota-gut-brain axis are associated with the onset of autism spectrum disorder (ASD). Numerous studies have reported that the gut microbiota (GM) is significantly altered in individuals with ASD and animal models of ASD. However, few studies have focused on sex-specific differences in the GM and fecal metabolites of ASD. Methods: In this study, we performed 16S rRNA gene sequencing and untargeted metabolomics in parallel on fecal samples from a valproic acid (VPA)-induced rat model of autism (VPA rats). Based on these data, we analyzed differentially abundant metabolites in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database to reveal the possible mechanism of ASD. Data derived from male and female rats were analyzed separately. Finally, we analyzed the correlation between characteristic genera and characteristic fecal metabolites in VPA rats of both sexes. Results: The results showed that VPA rats of both sexes presented remarkable alterations in the GM and fecal metabolites. Sex-specific differences were noticeably detected. We identified 51 annotated differentially abundant fecal metabolites and 1 differentially enriched KEGG pathway between the male VPA and male control groups. Ruminococcus_2, Candidatus_Soleaferrea, Desulfovibrio, Candidatus_Saccharimonas, Intestinimonas, [Eubacterium]_xylanophilum_group, [Eubacterium]_brachy_group and [Bacteroides]_pectinophilus_group were the characteristic genera of male VPA rats. Between the female VPA and female control groups, 124 annotated differentially abundant fecal metabolites were identified without differentially enriched KEGG pathways. Ruminiclostridium, Acetatifactor, Desulfovibrio, [Eubacterium]_xylanophilum_group and Candidatus_Saccharimonas were the characteristic genera of female VPA rats. Correlation analysis revealed a tight relationship between the GM and fecal metabolites in VPA rats of both sexes. Conclusions: In conclusion, alterations in the GM and fecal metabolites in VPA rats showed sex-specific differences. The therapy for ASD might be different between sexes in the future.

To study the effect of water and salt erosion on the bonded interface shear performance of a double-layer asphalt mixture (DLAM), an inclined shear test was conducted on a DLAM using a tack coat as the bonded interface between simulated old asphalt pavement (AC-16) and overlay (SMA-13). First, the inclined shear test of the DLAM before and after freeze–thaw (F–T) cycles was conducted. Second, the digital image correlation (DIC) technique was used to calculate the deformation field to divide the failure of the specimen into meso- and macrocracks and analyze them. According to the results of this study, the shear failure of DLAM under F–T cycles consisted of two stages. In the first stage (three cycles), the interface shear properties decreased due to ice expansion load. In the second stage (after three cycles), the interface shear performance deteriorated, and chlorine salts accelerated the interlayer failure due to the interface debonding of asphalt and aggregate under the combined action of water/salt and vehicle load. The damage factor defined on the basis of the statistical analysis of the strain field by DIC could reflect the deformation of the bonded interface in real time. The damage factor evolution curve was used to compare the interface damage degree caused by water and salt erosion. A method for judging the crack initiation area of mesocracks was proposed by DIC technology, and the correctness of the appearance position of the interface crack was verified by calculation.