Jing Zhang

The aggregation behavior of typical aromatic pollutants in the n-octanol phase and its influence on the n-octanol–air partition coefficient (K_OA) were investigated using molecular dynamics simulation. The aggregate proportion of selected aromatic pollutants gradually increased with increasing simulation time and then reached a dynamic equilibrium state. It is interesting to find that the higher the concentration of aromatic pollutants, the more aggregates formed in the n-octanol phase. Log K_OA values of these aromatic pollutants were subsequently estimated based on the percentages of aggregates and the solvation free energy from the gas phase to the n-octanol phase. The log K_OA values were also found to gradually increase with increasing concentration. Therefore, the effect of concentration on K_OA should be taken into consideration during the analysis of the environmental behavior and transport of these aromatic pollutants. In addition, it was found that π–π interactions drive the formation of different numbers of aggregates for different aromatic pollutants, a phenomenon that affects the K_OA values of aromatic pollutants. The above results shed some light on the effects of aggregates and concentration on the partition behavior of aromatic pollutants and provide a theoretical basis for the correction of K_OA of aromatic pollutants in the environment.

The knee joint is one of the most important joints in our lower body, affecting humans’ lower limb activities. For instance, the knee joint can even bear three to four times the human body’s weight when running and climbing. The knee joint is prone to degenerative lesions for older people as they age, which significantly affects their daily lives. Therefore, long-term and real-time assessment of lower-limb motions in older people is crucial for their lower-limb health detection. In this work, we developed wearable knee sensors based on nanocomposite e-textile strain sensors for detecting knee joints’ range of motion (ROM) while older people perform lower-limb activities. A total of ten features were extracted to characterize their STS performance by detecting their knee joint range of motion through normal speed and fast speed sit-to-stand (STS). The elderly subjects were grouped by their age, gender, and body mass index (BMI) to assess the relationship of these three parameters with the extracted features. As a result, the stability, ROM, and gender of elderly subjects while performing fast speed STS had a significant relationship with age and BMI (P<0.05). The result demonstrates the generalizability of e-textile sensors for assessing lower-limb motions, which shows great potential for long-term and real-time detection of lower-limb health in older people.

Once released into natural water, the environmental behavior and fate of C₆₀ could inevitably been affected by humic acid (HA), sunlight, and hydrodynamic conditions. However, the combined effects of these factors are not so clear. Therefore, in the present study, effects of HA, sunlight, and agitation intensity on generation and properties of aqu/nC₆₀ were investigated. The results indicated that HA could increase the concentration of aqu/nC₆₀ mainly through the steric hindrance effect. The higher agitation intensity led to higher concentrations of aqu/nC₆₀ and more efficient steric stabilization was formed by HA. Sunlight irradiation promoted the surface oxidization and consequently enhanced the dispersion of C₆₀. The relative order of the influence on the UV/vis concentration was sunlight > agitation intensity > HA. In addition, HA might not always enhance the dispersion of aqu/nC₆₀ due to light screening/ROS scavenging, over-coating, or chain-like bridging mechanism. Therefore, evaluating the environmental behavior and fate of C₆₀ should take these factors into account together.

Environmental waters cover a range of water quality characteristics which could greatly affect the behavior and fate of C₆₀ in the aquatic environment. In this study, the dispersion and stability of C₆₀ in several environmental water matrices during a 70-day extended mixing period were investigated to better understand its environmental behavior and fate in environmental waters. Relatively stable nanoscale aggregates in water (aqu/nC₆₀) could be formed in wastewater influent, while unstable suspensions were obtained in river water, wastewater effluent, seawater, and estuarine water. During the extended mixing under sunlight, oxygen-containing moieties were produced on the surface of the C₆₀ aggregates, independent of the kind of environmental water matrices. Once the mixed system went under quiescent condition, aggregation and sedimentation of aqu/nC₆₀ occurred. However, an extremely short-time disturbance could easily resuspend the C₆₀ aggregates deposited and increase the concentration of aqu/nC₆₀ in the overlying water column. Therefore, the effects of resuspension should be considered when investigating the environmental behavior and fate of C₆₀.