It is important to understand the fragmentation processes and mechanisms of plastic litter to predict microplastic production in the marine environment. In this study, accelerated weathering experiments were performed in the laboratory, with ultraviolet (UV) exposure for up to 12 months followed by mechanical abrasion (MA) with sand for 2 months. Fragmentation of low-density polyethylene (PE), polypropylene (PP), and expanded polystyrene (EPS) was evaluated under conditions that simulated a beach environment. PE and PP were minimally fragmented by MA without photooxidation by UV (8.7 ± 2.5 and 10.7 ± 0.7 particles/pellet, respectively). The rate of fragmentation by UV exposure duration increased more for PP than PE. A 12-month UV exposure and 2-month MA of PP and PE produced 6084 ± 1061 and 20 ± 8.3 particles/pellet, respectively. EPS pellets were susceptible to MA alone (4220 ± 33 particles/pellet), while the combination of 6 months of UV exposure followed by 2 months of MA produced 12,152 ± 3276 particles/pellet. The number of fragmented polymer particles produced by UV exposure and mechanical abrasion increased with decreasing size in all polymer types. The size-normalized abundance of the fragmented PE, PP, and EPS particles according to particle size after UV exposure and MA was predictable. Up to 76.5% of the initial EPS volume was unaccounted for in the final volume of pellet produced particle fragments, indicating that a large proportion of the particles had fragmented into undetectable submicron particles.

We demonstrate experimental data to elucidate the reason for the discrepancies of reported band gap energy (Eg) of Cu2ZnSnSe4 (CZTSe) thin films, i.e., 1.0 or 1.5 eV. Eg of the coevaporated CZTSe film synthesized at substrate temperature (Tsub) of 370 °C, which was apparently phase pure CZTSe confirmed by x-ray diffraction (XRD) and Raman spectroscopy, is found to be around 1 eV regardless of the measurement techniques. However, depth profile of the same sample reveals the formation of ZnSe at CZTSe/Mo interface. On the other hand, Eg of the coevaporated films increases with Tsub due to the ZnSe formation, from which we suggest that the existence of ZnSe, which is hardly distinguishable from CZTSe by XRD, is the possible reason for the overestimation of overall Eg.

Combined determination of AFP-L3 and PIVKA-II could improve the diagnostic value for HCC detection in patients with or without increased AFP levels.

The clinical use of human bone marrow–derived mesenchymal stem cells (BM-MSCs) has been hampered by their poor performance after transplantation into failing hearts. Here, to improve the therapeutic potential of BM-MSCs, we developed a strategy termed in vivo priming in which BM-MSCs are primed in vivo in myocardial infarction (MI)–induced hearts through genetically engineered hepatocyte growth factor–expressing MSCs (HGF-eMSCs) that are encapsulated within an epicardially implanted 3D cardiac patch. Primed BM-MSCs through HGF-eMSCs exhibited improved vasculogenic potential and cell viability, which ultimately enhanced vascular regeneration and restored cardiac function to the MI hearts. Histological analyses further demonstrated that the primed BM-MSCs survived longer within a cardiac patch and conferred cardioprotection evidenced by substantially higher numbers of viable cardiomyocytes in the MI hearts. These results provide compelling evidence that this in vivo priming strategy can be an effective means to enhance the cardiac repair of MI hearts.