The COVID-19 pandemic has led to an increased demand for single-use plastics that intensifies pressure on an already out-of-control global plastic waste problem. While it is suspected to be large, the magnitude and fate of this pandemic-associated mismanaged plastic waste are unknown. Here, we use our MITgcm ocean plastic model to quantify the impact of the pandemic on plastic discharge. We show that 8.4 ± 1.4 million tons of pandemic-associated plastic waste have been generated from 193 countries as of August 23, 2021, with 25.9 ± 3.8 thousand tons released into the global ocean representing 1.5 ± 0.2% of the global total riverine plastic discharge. The model projects that the spatial distribution of the discharge changes rapidly in the global ocean within 3 y, with a significant portion of plastic debris landing on the beach and seabed later and a circumpolar plastic accumulation zone will be formed in the Arctic. We find hospital waste represents the bulk of the global discharge (73%), and most of the global discharge is from Asia (72%), which calls for better management of medical waste in developing countries.

Stabilization and overexpression are hallmarks of mutant p53 found in nearly 50% of human tumors. Mutations in the conformation-sensitive core domain of p53 often lead to association with molecular chaperones such as hsp70 and hsp90. Inhibition of hsp90 function accelerates mutant p53 degradation. We recently found that expression of p53 core domain mutants inhibits MDM2 degradation, suggesting that mutant p53 can modulate MDM2 functions. In this report, we show that mutant p53 mediates formation of MDM2-p53-hsp90 complexes. Release of MDM2 from the p53-hsp90 complex after DNA damage restores MDM2 but not p53 turnover, whereas dissociation of hsp90 by geldanamycin increases the degradation of both MDM2 and mutant p53. Mutant p53 degradation after hsp90 inhibition requires MDM2 expression. The interaction between MDM2 and hsp90 is disrupted by the 2A10 antibody, which recognizes a site on MDM2 important for binding to alternative reading frame (ARF). Expression of mutant p53 prevents MDM2 from binding ARF and accumulating in the nucleolus in an hsp90-dependent fashion. These results suggest that hsp90 recruited by mutant p53 conceals the ARF-binding site on MDM2 and inhibits its ubiquitin-protein isopeptide ligase function, resulting in the stabilization of both mutant p53 and MDM2.The p53 tumor suppressor is mutated in about 55% of human tumors. The majority of mutations are single amino acid substitutions in the DNA-binding (core) domain of p53 (1). In normal cells, p53 is present at very low levels due to rapid degradation mediated by MDM2. MDM2 binds to p53 and promotes its ubiquitination by acting as a ubiquitin E3 1 ligase (2-4). Expression of MDM2 is activated by p53 at the transcription level (5, 6). Therefore, MDM2 functions as a negative feedback regulator to maintain p53 at low levels. In response to stress or DNA damage, p53 is stabilized through multiple mechanisms, such as phosphorylation of p53, expression of the MDM2 inhibitor ARF, and inhibition of MDM2 expression (7).ARF binding inhibits the ubiquitin E3 ligase function of MDM2 and sequesters MDM2 into the nucleolus (8 -10).In general, tumor cells with mutant p53 accumulate p53 to high levels. The inability of mutant p53 to induce sufficient MDM2 expression is an important mechanism that contributes to the stabilization of p53 (11). However, other studies suggest that binding of heat shock protein hsp90, which is a common feature of p53 mutants, may also play a role in the stabilization of mutant p53 (12-14). Inhibition of p53-hsp90 binding using benzoquinone ansamycin antibiotics (geldanamycin) that bind specifically to the ATP-binding domain of hsp90 can lead to enhanced ubiquitination and degradation of mutant p53 (14,15). Therefore, mutant p53 may be resistant to degradation in part due to binding of hsp90.Understanding the mechanism of mutant p53 stabilization may have practical significance in addition to explaining a tumor-specific phenomenon. Although the major consequence of p53 mutation is loss of tumor suppressor function, accumulatio...

Flexible perovskite solar cells (f‐PSCs) have attracted great attention due to their promising commercial prospects. However, the performance of f‐PSCs is generally worse than that of their rigid counterparts. Herein, it is found that the unsatisfactory performance of planar heterojunction (PHJ) f‐PSCs can be attributed to the undesirable morphology of electron transport layer (ETL), which results from the rough surface of the flexible substrate. Precise control over the thickness and morphology of ETL tin dioxide (SnO2) not only reduces the reflectance of the indium tin oxide (ITO) on polyethylene 2,6‐naphthalate (PEN) substrate and enhances photon collection, but also decreases the trap‐state densities of perovskite films and the charge transfer resistance, leading to a great enhancement of device performance. Consequently, the f‐PSCs, with a structure of PEN/ITO/SnO2/perovskite/Spiro‐OMeTAD/Ag, exhibit a power conversion efficiency (PCE) up to 19.51% and a steady output of 19.01%. Furthermore, the f‐PSCs show a robust bending resistance and maintain about 95% of initial PCE after 6000 bending cycles at a bending radius of 8 mm, and they present an outstanding long‐term stability and retain about 90% of the initial performance after >1000 h storage in air (10% relative humidity) without encapsulation.

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