Dechlorane plus in dust, hair and urine: Exposure, excretion and level change.

Dechlorane plus (DP) has been detected in a variety of environmental media and in human. Measurement of DPs in hair, urine, and house dust across different habitats allows for the assessment of short-term spatial changes in human exposure to DPs, as well as their excretion in urine. This offers a significant reference point for further research on the behavior of persistent pollutants within organisms. We measured and analyzed the concentrations of DP in the hair and urine of 32 students from a university in Beijing during school and home phases, and in indoor dust from dormitories and some home environments. The results indicated that the concentrations of DP in three types of samples were higher during the home phase compared to the school phase. We compared the fanti values and identified selective enrichment of syn-DP in hair, along with selective excretion of syn-DP in urine. Utilizing molecular docking technique, we simulated the binding effect between DP and the Megalin protein. The results demonstrated that the binding energy of anti-DP to Megalin was higher than that of syn-DP, suggesting that anti-DP has a greater propensity to bind to Megalin and be reabsorbed. This results in higher levels of syn-DP excretion in urine. Finally, we categorized students based on their participation in the organic exposure experiment and their BMI. The results indicated that the concentrations of DP in hair and urine were higher in the exposed group compared to the non-exposed group during the school year. After excluding the effect of exposure, habitat changes were more likely to affect the accumulation and excretion of DP in normal-weight students (BMI ≤24 kg/m2, n = 28), while overweight students (BMI >24 kg/m2, n = 4) were less affected by the effect of habitat because of their higher body fat percentage and their greater ability to accumulate DP.

Polybrominated diphenyl ethers in dust, hair and urine: Exposure, excretion.

Polybrominated diphenyl ethers (PBDEs) have been detected in various environmental media and human tissues. PBDEs concentrations in dust from college buildings and homes and in paired hair and urine samples from students were determined. This is of great significance to explore the accumulation and excretion patterns of PBDEs in the human body. The median PBDEs concentrations in the dust (College: 84.59 ng/g; Home: 170.32 ng/g) and hair (undergraduate: 6.16 ng/g; Home: 3.25 ng/g) samples were generally lower than were found in the majority of previous studies. The PBDEs concentrations in the hair and urine samples were subjected to principal component analysis, and the results combined with the PBDEs detection rates confirmed that hair is a useful non-invasive sampling medium for assessing PBDEs exposure and the risks posed. Body mass indices (BMIs) were used to divide students who had not been exposed to large amounts of PBDEs into groups. Body fat percentage is an important factor affecting the accumulation of PBDE in the human body. Environmental factors were found to affect the PBDEs concentrations in the hair and urine samples less for normal-weight students (BMI≤24) than overweight students (BMI>24). Short-term environmental changes to more readily affect the PBDEs concentrations in the tissues of the normal-weight than overweight students. PBDEs with seven or more bromine substituents were found not to be readily excreted in urine. Performing molecular docking simulations of the binding of isomers BDE-99 and BDE-100 to megalin. The binding energy was higher for BDE-100 and megalin than for BDE-99 and megalin, meaning BDE-99 would be more readily excreted than BDE-100.

Critical Rolling Process Parameters for Dynamic Recrystallization Behavior of AZ31 Magnesium Alloy Sheets.

In this work, the influence of various rolling temperatures and thickness reductions on the dynamic recrystallization (DRX) behavior of AZ31 magnesium alloy sheets was investigated. Meanwhile, the texture variation controlled by DRX behavior was analyzed. Results suggested that, with the help of DRX behavior, reasonable matching of rolling temperature and thickness reduction could effectively refine the grain size and improve the microstructure homogeneity. Using the grain refinement and microstructure homogeneity as the reference, the critical rolling process parameters were 400 °C-30%, 300 °C-30%, and 250 °C-40% in the present work. In terms of basal texture variation, the occurrence of twins produced the largest maximum texture intensity. However, for the sheets with DRX behavior, the maximum texture intensity decreased sharply, but would steadily increase with the growth of DRXed grain. Additionally, for DRXed grains, the <11-20>//RD (RD: rolling direction) grains would gradually annex the <10-10>//RD grains with the growth of DRXed grains, which finally made their texture component become the dominant texture state. However, when the deformation continued, the <10-10> in DRXed grains would rotate toward the RD again. Weighted by the fracture elongation of AZ31 magnesium alloy sheet, the critical thickness reductions were 30⁻40% under the rolling temperature of 400 °C.

Degradable magnesium-based implant materials with anti-inflammatory activity.

The objective of this study was to prepare a new biodegradable Mg-based biomaterial, which provides good mechanical integrity in combination with anti-inflammatory function during the degradation process. The silver element was used, because it improved the mechanical properties as an effective grain refiner and it is also treated as a potential anti-inflammatory core. The new degradable Mg-Zn-Ag biomaterial was prepared by zone solidification technology and extrusion. The mechanical properties were mostly enhanced by fine grain strengthening. In addition, the alloys exhibited good cytocompatibility. The anti-inflammatory function of degradation products was identified by both interleukin-1α and nitric oxide modes. The anti-inflammatory impact was significantly associated with the concentration of silver ion. It was demonstrated that Mg-Zn-Ag system was a potential metallic stent with anti-inflammatory function, which can reduce the long-term dependence of anti-inflammatory drug after coronary stent implantation.