Dynamic Analysis of Stool Microbiota of Simmental Calves and Effects of Diarrhea on Their Gut Microbiota.

The objective of this study was to explore the dynamic changes in the gut microbiota of Simmental calves before weaning and to compare the microbial composition and functionality between healthy calves and those with diarrhea. Fourteen neonatal Simmental calves were divided into a healthy group (n = 8) and a diarrhea group (n = 6). Rectal stool samples were collected from each calf on days 1, 3, 5, 7, 9, 12, 15, 18, 22, 26, 30, 35, and 40. High-throughput sequencing of the 16S rRNA gene V1-V9 region was conducted to examine changes in the gut microbiota over time in both groups and to assess the influence of diarrhea on microbiota structure and function. Escherichia coli, Bacteroides fragilis, and B. vulgatus were the top three bacterial species in preweaning Simmental calves. Meanwhile, the major functions of the fecal microbiota included "metabolic pathways", "biosynthesis of secondary metabolites", "biosynthesis of antibiotics", "microbial metabolism in diverse environments", and "biosynthesis of amino acids". For calves in the healthy group, PCoA revealed that the bacterial profiles on days 1, 3, 5, 7, and 9 differed from those on days 15, 18, 22, 26, 30, 35, and 40. The profiles on day 12 clustered with both groups, indicating that microbial structure changes increased with age. When comparing the relative abundance of bacteria between healthy and diarrheic calves, the beneficial Lactobacillus johnsonii, Faecalibacterium prausnitzii, and Limosilactobacillus were significantly more abundant in the healthy group than those in the diarrhea group (p < 0.05). This study provides fundamental insights into the gut microbiota composition of Simmental calves before weaning, potentially facilitating early interventions for calf diarrhea and probiotic development.

Residues, potential source and ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface water of the East Liao River, Jilin Province, China.

The environmental risks posed by polycyclic aromatic hydrocarbons (PAHs) and the diversity of their anthropogenic origins make them a global issue. Therefore, it is of utmost significance for protecting the aquatic environment and the growth of neighboring populations to identify their possible origins and ecological risk. Here, we detail the contamination profiles of 15 PAHs found in the East Liao River's surface waters in Jilin Province and use the receptor model Absolute Principal Component Analysis - Multiple Linear Regression (APCS-MLR) and diagnostic ratios method to identify the primary potential sources of pollution. Based on the natural hazard risk formation theory (NHRFT), an ecological risk assessment (ERA) model for PAHs in the East Liao River was developed. The method assesses the ecological risk status of PAHs by integrating the risk quotient (RQ) approach and the DPSIRM (driving force, pressure, state, impact, response, management) conceptual framework. Total concentrations in the surface water body were between 396.42 and 624.06 ng/L, with an average of 436.99 ng/L. The source research revealed that coal, biomass, and traffic emission sources are the most likely PAH contributors to the East Liao River. The ERA found that the majority of the sites' locations of the study were at low risk for PAHs in surface water bodies (30.7 % and 32.2 %, respectively), while only a tiny percentage of sites were at high or very high risk (1.8 % and 13.6 %). The study results provide theoretical support for the East Liao River's ecological, environmental protection, and policy formulation.

Role of an external electric field on hybrid halide perovskite CH3NH3PbI3 band gaps.

The organic-inorganic perovskite CH3NH3PbI3 has attracted much attention due to their power conversion efficiency as a potential photovoltaic material, but the role of an external electric field has not been well understood. Based on first-principles calculations, the effects of an external electric field (E) applied along the [111] direction of the orthorhombic perovskite, CH3NH3PbI3, on its electronic structure and optical properties are investigated. Our results indicate that the electric field strength affects the band gap (Eg) of CH3NH3PbI3 (MAPbI3, MA = CH3NH3). The energy difference between the two peaks closest to the Fermi level in the density of states diagram decreases with increasing applied electric field strength along the [111] direction, indicating that the covalent character increases between A-sites cations and I-sites anions. Both the cell volume and the final energy show the same increasing trend. The absorption peaks move toward the visible-frequency range, with the optimal band gap of 1.1-1.45 eV and E = 0.04-0.06 eV/Å/e. In particular, the non-linear change of the second-order Stark effect causes a non-linear change in the band gap.