Three birds, one stone: Disinfecting and turning waste medical masks into valuable carbon dots for sodium hydrosulfite and Fe3+ detection enabled by a simple hydrothermal treatment.

Disposable medical masks are widely used to prevent respiratory infections due to their ability to block virus particles from entering the human body. The coronavirus disease 2019 (COVID-19) pandemic highlighted the importance of medical masks, leading to their widespread use around the world. However, a large number of disposable medical masks have been discarded, some carrying viruses, which have posed a grave threat to the environment and people's health, as well as wasting resources. In this study, a simple hydrothermal method was used for the disinfection of waste medical masks under high-temperature conditions as well as for their transformation into high-value-added carbon dots (CDs, a new type of carbon nanomaterial) with blue-emissive fluorescence, without high energy consumption or environmental pollution. Moreover, the mask-derived CDs (m-CDs) could not only be used as fluorescent probes for sensing sodium hydrosulfite (Na2S2O4), which is widely used in the food and textile industries but is seriously harmful to human health, but also be used for detecting Fe3+ which is harmful to the environment and human health due to its wide use in industries.

An engineered bispecific human monoclonal antibody against SARS-CoV-2.

The global severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic requires effective therapies against coronavirus disease 2019 (COVID-19), and neutralizing antibodies are a promising therapy. A noncompeting pair of human neutralizing antibodies (B38 and H4) blocking SARS-CoV-2 binding to its receptor, ACE2, have been described previously. Here, we develop bsAb15, a bispecific monoclonal antibody (bsAb) based on B38 and H4. bsAb15 has greater neutralizing efficiency than these parental antibodies, results in less selective pressure and retains neutralizing ability to most SARS-CoV-2 variants of concern (with more potent neutralizing activity against the Delta variant). We also selected for escape mutants of the two parental mAbs, a mAb cocktail and bsAb15, demonstrating that bsAb15 can efficiently neutralize all single-mAb escape mutants. Furthermore, prophylactic and therapeutic application of bsAb15 reduced the viral titer in infected nonhuman primates and human ACE2 transgenic mice. Therefore, this bsAb is a feasible and effective strategy to treat and prevent severe COVID-19.

Earth Materials and Environmental Applications 2020

The road performance, dynamic properties, and environment impact tests on mechanical property and environmental safety of an industrial residue waste subgrade material were evaluated. The effect of calcium carbonate on the mechanical properties and microstructure of red clay was studied by adding precipitated calcium carbonate to red clay at ratios of 0%, 5%, 10%, 15%, and 20%, and then, shear tests were conducted. In the study of sorptive removal of color dye safranin O (SO) by fibrous clay minerals and zeolites, it was found that the cation exchange capacity (CEC) of the minerals played a key role in SO+ removal and the sorbed SO+ cations were limited to the external surfaces of the minerals due to limited channel size of the fibrous minerals.

Clinical characteristics and risk factors of mortality in elderly patients with novel coronavirus pneumonia

Objective: To explore the clinical characteristics and risk factors of mortality in the elderly patients with novel coronavirus pneumonia(COVID-19).

Temporary vaccination clinic for COVID-19 in Zhuhai, China.

Vaccines are urgently needed to control the COVID-19 pandemic. To gradually increase the vaccination rate among residents, temporary vaccination clinic for COVID-19 plays an important role. It should be located in an area with convenient transportation and concentrated population. Functional zones including waiting and inquiry, registration and notification, injection, observation and emergency room should be established. All vaccine recipients' information should be uploaded to the national immunization information system. Medical staff at the temporary vaccination clinic should be professionally trained. A cautious disinfection and wiping are essential for the temporary vaccination clinic.

Simultaneous detection of the spike and nucleocapsid proteins from SARS-CoV-2 based on ultrasensitive single molecule assays.

Nucleic acid detection technology based on polymerase chain reaction (PCR) and antibody detection based on immunochromatography still have many problems such as false negatives for the diagnosis of coronavirus disease 2019 (COVID-19). Therefore, it is of great importance to develop new techniques to improve the diagnostic accuracy of COVID-19. We herein developed an ultrasensitive, rapid, and duplex digital enzyme-linked immunosorbent assay (dELISA) for simultaneous detection of spike (S-RBD) and nucleocapsid (N) proteins of SARS-CoV-2 based on a single molecule array. This assay effectively combines magnetic bead encoding technology and the ultrasensitive detection capability of a single molecule array. The detection strategies of S-RBD protein and N-protein exhibited wide response ranges of 0.34-1065 pg/mL and 0.183-338 pg/mL with detection limits of 20.6 fg/mL and 69.8 fg/mL, respectively. It is a highly specific method for the simultaneous detection of S-RBD protein and N-protein and has minimal interference from other blood proteins. Moreover, the spike assay showed a satisfactory and reproducible recovery rate for the detection of S-RBD protein and N-protein in serum samples. Overall, this work provides a highly sensitive method for the simultaneous detection of S-RBD protein and N-protein, which shows ultrasensitivity and high signal-to-noise ratio and contributes to improve the diagnosis accuracy of COVID-19.

Impact of COVID-19 on Financial Constraints and the Moderating Effect of Financial Technology

The sudden outbreak of COVID-19 has made enterprises in various countries face extreme financial constraints. Using the quarterly data of Chinese listed companies from 2011 to 2020, we examine the impact of COVID-19 on financial constraints and the moderating effect of financial technology. We find that while COVID-19 has increased enterprises’ financial constraints, the development of financial technology can mitigate its negative impact. The results still hold under various robustness checks. While the COVID-19 pandemic is still ongoing, there is scope for the future development of financial technology to help protect and revive the global economy.

A noncompeting pair of human neutralizing antibodies block COVID-19 virus binding to its receptor ACE2.

Neutralizing antibodies could potentially be used as antivirals against the coronavirus disease 2019 (COVID-19) pandemic. Here, we report isolation of four human-origin monoclonal antibodies from a convalescent patient, all of which display neutralization abilities. The antibodies B38 and H4 block binding between the spike glycoprotein receptor binding domain (RBD) of the virus and the cellular receptor angiotensin-converting enzyme 2 (ACE2). A competition assay indicated different epitopes on the RBD for these two antibodies, making them a potentially promising virus-targeting monoclonal antibody pair for avoiding immune escape in future clinical applications. Moreover, a therapeutic study in a mouse model validated that these antibodies can reduce virus titers in infected lungs. The RBD-B38 complex structure revealed that most residues on the epitope overlap with the RBD-ACE2 binding interface, explaining the blocking effect and neutralizing capacity. Our results highlight the promise of antibody-based therapeutics and provide a structural basis for rational vaccine design.