Sex-specific associations between legacy and novel per- and polyfluoroalkyl substances and telomere length in newborns in Wuhan, China: Mixture and single pollutant associations.

Telomere length (TL) at birth predicts later life TL and is related to health. Prenatal exposure to environmental pollutants might affect TL, but the associations between intrauterine per- and polyfluoroalkyl substances (PFASs) exposure and neonatal TL remained inconclusive. This study aimed to explore the single pollutant and mixture associations between legacy and novel PFASs and TL in newborns. In 908 mother-newborn pairs from Wuhan, China, thirteen PFASs were measured in cord serum, and TL was determined in cord leukocytes. Weighted quantile sum (WQS) regression and generalized linear model (GLM) were utilized to analyze the associations between PFASs mixture and single PFASs and TL in newborns. Furthermore, stratified and interaction analyses were performed to evaluate if there were sex-specific associations. The concentrations of perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) ranked the highest (geometric mean, 4.12, 1.61, and 0.77 ng/mL, respectively) among the 13 measured PFASs. Each unit increase in WQS index of PFASs mixture was associated with -5.19 % change (95% CI, -9.44, -0.73) of neonatal TL, and 8:2 Cl-PFESA contributed most (32.59 %) to the mixture association. In stratified analyses by neonatal sex, PFOS (-4.73 % change, 95% CI, -8.40, -0.93 for per doubling concentration) and 8:2 Cl-PFESA (-4.52 % change, 95% CI, -8.20, -0.70) were negatively associated with neonatal TL in male newborns, but no significant association appeared in females. In summary, intrauterine exposure to PFASs in mixture was associated with shorter neonatal TL, and the negative associations of 8:2 Cl-PFESA and PFOS with neonatal TL were observed only in boys. Future risk assessments are needed to pay more attention to the health effects of novel PFASs.

Regulation of Myogenic Differentiation by Topologically Microgrooved Surfaces for Skeletal Muscle Tissue Engineering.

Inspired by the natural topological structure of skeletal muscle tissue, the topological surface construction of bionic scaffolds for skeletal muscle repair has attracted great interest. Many previous studies have focused on the effects of the topological structure on myoblasts. However, these studies used only specific repeating sizes and shapes to achieve the myoblast alignment and myotube formation; moreover, the regulatory effects of the size of a topological structure on myogenic differentiation are often neglected, leading to a lack of guidance for the design of scaffolds for skeletal muscle tissue engineering. In this study, we fabricated a series of microgroove topographies with various widths and depths via a combination of soft lithography and melt-casting and studied their effects on the behaviors of skeletal muscle cells, especially myogenic differentiation, in detail. Microgrooved poly(lactic-co-glycolic acid) substrates were found to effectively regulate the proliferation, myogenic differentiation, and myotube formation of C2C12 cells, and the degree of myogenic differentiation was significantly dependent on signals in response to the size of the microgroove structure. Compared with their depth, the width of the microgroove structures can more strongly affect the myogenic differentiation of C2C12 cells, and the degree of myoblast differentiation was enhanced with increasing groove width. Microgroove structures with relatively large groove widths and small groove depths promoted the myogenic differentiation of C2C12 cells. In addition, the integrin-mediated focal adhesion kinase signaling pathway and MAPK signaling pathway were activated in cells in response to the external topological structure, and the size of the topological structure of the material surface effectively regulated the degree of the cellular response to the external topological structure. These results can guide the design of scaffolds for skeletal muscle tissue engineering and the construction of effective bionic scaffold surfaces for skeletal muscle regeneration.

Effect of alternating current and Bacillus cereus on the stress corrosion behavior and mechanism of X80 steel in a Beijing soil solution.

The effects of alternating current (AC) and Bacillus cereus (B. cereus) on the stress corrosion behavior and mechanism of X80 pipeline steel were investigated in a Beijing soil solution in this study. Both AC and B. cereus can promote the generation of pits in X80 steel. B. cereus is a type of nitrate-reducing bacteria and hence nitrate reduction occurs at the bottom of the corrosion product film or the biofilm. Meanwhile, the anode accelerates the dissolution of X80 steel and generates some pits in the local working area. The synergistic effect of AC and nitrate- reducing bacteria (NRB) promotes X80 steel corrosion and increases its susceptibility to stress corrosion cracking (SCC).

Corrosion behavior of X80 pipeline steel in the presence of Brevibacterium halotolerans in Beijing soil.

In this study, the corrosion behavior of X80 pipeline steel in the presence of Brevibacterium halotolerans (B. halotolerans) was investigated by surface analysis and electrochemical measurements. Results show that B. halotolerans can attach to the surface of X80 steel, and the entire surface is covered with B. halotolerans. The corrosion products induced by B. halotolerans were FeOOH, Fe2O3 and FeSO4. X80 steel corrosion was accelerated in the presence of B. halotolerans and was susceptible to pitting corrosion. The formation of pitting corrosion could be due that the B. halotolerans oxidization of elemental iron in X80 steel to either obtain electrons from the reduction of nitrate in the underlying biofilm or in the damaged corrosion product film.

Corrosion effect of Bacillus cereus on X80 pipeline steel in a Beijing soil environment.

The corrosion of X80 pipeline steel in the presence of Bacillus cereus (B. cereus) was studied through electrochemical and surface analyses and live/dead staining. Scanning electron microscopy and live/dead straining results showed that a number of B. cereus adhered to the X80 steel. Electrochemical impedance spectroscopy showed that B. cereus could accelerate the corrosion of X80 steel. In addition, surface morphology observations indicated that B. cereus could accelerate pitting corrosion in X80 steel. The depth of the largest pits due to B. cereus was approximately 11.23µm. Many pits were found on the U-shaped bents and cracks formed under stress after 60days of immersion in the presence of B. cereus. These indicate that pitting corrosion can be accelerated by B. cereus. X-ray photoelectron spectroscopy results revealed that NH4+ existed on the surface of X80 steel. B. cereus is a type of nitrate-reducing bacteria and hence the corrosion mechanism of B. cereus may involve nitrate reduction on the X80 steel.

Failure Mechanisms of the Coating/Metal Interface in Waterborne Coatings: The Effect of Bonding.

Waterborne coating is the most popular type of coating, and improving its performance is a key point of research. Cathodic delamination is one of the major modes of failure for organic coatings. It refers to the weakening or loss of adhesion between the coating and substrate. Physical and chemical characteristics of coatings have been studied via scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle measurements, Fourier transform infrared spectroscopy (FTIR), and secondary ion mass spectrometry (SIMS). Early heterogeneous swelling at the metal-coating interface in non-defective coated metals was elucidated using frequency-dependent alternating-current scanning electrochemical microscopy. Two types of coatings (styrene-acrylic coating and terpolymer coating) were compared. The effects of thickness, surface roughness, and chemical bonding on cathodic delamination were investigated.

Effect of Zinc Phosphate on the Corrosion Behavior of Waterborne Acrylic Coating/Metal Interface.

Waterborne coating has recently been paid much attention. However, it cannot be used widely due to its performance limitations. Under the specified conditions of the selected resin, selecting the function pigment is key to improving the anticorrosive properties of the coating. Zinc phosphate is an environmentally protective and efficient anticorrosion pigment. In this work, zinc phosphate was used in modifying waterborne acrylic coatings. Moreover, the disbonding resistance of the coating was studied. Results showed that adding zinc phosphate can effectively inhibit the anode process of metal corrosion and enhance the wet adhesion of the coating, and consequently prevent the horizontal diffusion of the corrosive medium into the coating/metal interface and slow down the disbonding of the coating.

Suppression of Hepatic Cyp1a2 by Total Ginsenosides in Lipopolysaccharide-Treated Mice and Primary Mouse Hepatocytes.

The roots of Panax ginseng (ginseng) have been extensively used in traditional Chinese medicine. However, herb-drug interactions between ginseng and other co-administered drugs are not fully understood concerning the effect of ginseng on drug metabolism and clearance. The current study aimed to elucidate the effect of total ginsenosides, a typical ginseng extract, on the regulation of Cyp1a2, a key enzyme to regulate drug metabolism under the normal and inflammatory conditions in mice. Female C57BL/6J mice treated with vehicle and lipopolysaccharide (LPS) were intragastrically administered ginseng extract for 7 days before hepatic P450 expression was analyzed. Primary mouse hepatocytes were also employed to further explore the effects of total ginsenosides on Cyp1a2 expression. The results showed that total ginsenosides in P. ginseng extract exhibited a concentration-dependent suppression on Cyp1a2 mRNA and protein level in both mice and primary mouse hepatocytes. Notably, the inhibitory effects of total ginsenosides on Cyp1a2 mRNA and protein expression were further enhanced following LPS treatment. Therefore, future research is warranted to investigate the role of ginsenosides in the regulation of hepatic CYP450s. Moreover, consumption of ginseng as food or supplement should be monitored for patients on combinational therapy, especially those with inflammatory diseases.

A Caco-2 cell-based quantitative antioxidant activity assay for antioxidants.

A Caco-2 cell-based antioxidant activity (CAA) assay for quantitative evaluation of antioxidants was developed by optimizing seeding density and culture time of Caco-2 cells, incubation time and concentration of fluorescent probe (2',7'-dichlorofluorescin diacetate, DCFH-DA), incubation way and incubation time of antioxidants (pure phytochemicals) and DCFH-DA with cells, and detection time of fluorescence. Results showed that the CAA assay was of good reproducibility and could be used to evaluate the antioxidant activity of antioxidants at the following conditions: seeding density of 5 × 10(4)/well, cell culture time of 24h, co-incubation of 60 µM DCFH-DA and pure phytochemicals with Caco-2 cells for 20 min and fluorescence recorded for 90 min. Additionally, a significant correlation was observed between CAA values and rat plasma ORAC values following the intake of antioxidants for selected pure phytochemicals (R(2) = 0.815, p < 0.01), demonstrating the good biological relevance of CAA assay.