Upcycling waste mask PP microfibers in portland cement paste: Surface treatment by graphene oxide

Used face masks resulting from the COVID-19 pandemic are forming a new waste stream that poses a considerable environmental risk to the ecosystem if not properly disposed of. This work explored an environmentally friendly solution to diverting such waste to a value-added application, i.e., fabricating waste mask microfibers for use in cementitious composites. To improve the interfacial transition zone between mask fibers and cement paste matrix, the microfibers made from recycled medical masks are pre-treated in an aqueous solution of graphene oxide (GO, at 0.05 wt%). In a cement paste with the water/cement ratio of 0.40, the GO-treated mask fibers admixed at 0.1 vol% showed great potential for improving the splitting tensile strength (by 47% at 28 days), even though they slightly decreased the compressive strength of the paste (by 3% at 28 days). Microscopic investigation was also carried out to reveal the enhancement mechanism of GO-treated fibers. This study preliminarily demonstrated the feasibility to upcycle waste masks in the concrete industry and provided a new strategy for disposing of waste masks.

Progressive deterioration of the upper respiratory tract and the gut microbiomes in children during the early infection stages of COVID-19.

Children are less susceptible to coronavirus disease 2019 (COVID-19), and they have manifested lower morbidity and mortality after infection, for which a multitude of mechanisms may be considered. Whether the normal development of the gut-airway microbiome in children is affected by COVID-19 has not been evaluated. Here, we demonstrate that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection alters the upper respiratory tract and the gut microbiomes in nine children. The alteration of the microbiome is dominated by the genus Pseudomonas, and it sustains for up to 25-58 days in different individuals. Moreover, the patterns of alternation are different between the upper respiratory tract and the gut. Longitudinal investigation shows that the upper respiratory tract and the gut microbiomes are extremely variable among children during the course of COVID-19. The dysbiosis of microbiome persists in 7 of 8 children for at least 19-24 days after discharge from the hospital. Disturbed development of both the gut and the upper respiratory microbiomes and prolonged dysbiosis in these nine children imply possible long-term complications after clinical recovery from COVID-19, such as predisposition to the increased health risk in the post-COVID-19 era.

The high diversity of SARS-CoV-2-related coronaviruses in pangolins alerts potential ecological risks.

Understanding the zoonotic origin and evolution history of SARS-CoV-2 will provide critical insights for alerting and preventing future outbreaks. A significant gap remains for the possible role of pangolins as a reservoir of SARS-CoV-2 related coronaviruses (SC2r-CoVs). Here, we screened SC2r-CoVs in 172 samples from 163 pangolin individuals of four species, and detected positive signals in muscles of four Manis javanica and, for the first time, one M. pentadactyla. Phylogeographic analysis of pangolin mitochondrial DNA traced their origins from Southeast Asia. Using in-solution hybridization capture sequencing, we assembled a partial pangolin SC2r-CoV (pangolin-CoV) genome sequence of 22 895 bp (MP20) from the M. pentadactyla sample. Phylogenetic analyses revealed MP20 was very closely related to pangolin-CoVs that were identified in M. javanica seized by Guangxi Customs. A genetic contribution of bat coronavirus to pangolin-CoVs via recombination was indicated. Our analysis revealed that the genetic diversity of pangolin-CoVs is substantially higher than previously anticipated. Given the potential infectivity of pangolin-CoVs, the high genetic diversity of pangolin-CoVs alerts the ecological risk of zoonotic evolution and transmission of pathogenic SC2r-CoVs.

Global Diversification and Distribution of Coronaviruses With Furin Cleavage Sites.

Knowledge about coronaviruses (CoVs) with furin cleavage sites is extremely limited, although these sites mediate the hydrolysis of glycoproteins in plasma membranes required for MERS-CoV or SARS-CoV-2 to enter cells and infect humans. Thus, we have examined the global epidemiology and evolutionary history of SARS-CoV-2 and 248 other CoVs with 86 diversified furin cleavage sites that have been detected in 24 animal hosts in 28 countries since 1954. Besides MERS-CoV and SARS-CoV-2, two of five other CoVs known to infect humans (HCoV-OC43 and HCoV-HKU1) also have furin cleavage sites. In addition, human enteric coronavirus (HECV-4408) has a furin cleavage site and has been detected in humans (first in Germany in 1988), probably via spillover events from bovine sources. In conclusion, the presence of furin cleavage sites might explain the polytropic nature of SARS-CoV-2- and SARS-CoV-2-like CoVs, which would be helpful for ending the COVID-19 pandemic and preventing outbreaks of novel CoVs.

A recombinant spike protein subunit vaccine confers protective immunity against SARS-CoV-2 infection and transmission in hamsters.

Multiple safe and effective vaccines that elicit immune responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are necessary to respond to the ongoing coronavirus disease 2019 (COVID-19) pandemic. Here, we developed a protein subunit vaccine composed of spike ectodomain protein (StriFK) plus a nitrogen bisphosphonate-modified zinc-aluminum hybrid adjuvant (FH002C). StriFK-FH002C generated substantially higher neutralizing antibody titers in mice, hamsters, and cynomolgus monkeys than those observed in plasma isolated from COVID-19 convalescent individuals. StriFK-FH002C also induced both TH1- and TH2-polarized helper T cell responses in mice. In hamsters, StriFK-FH002C immunization protected animals against SARS-CoV-2 challenge, as shown by the absence of virus-induced weight loss, fewer symptoms of disease, and reduced lung pathology. Vaccination of hamsters with StriFK-FH002C also reduced within-cage virus transmission to unvaccinated, cohoused hamsters. In summary, StriFK-FH002C represents an effective, protein subunit-based SARS-CoV-2 vaccine candidate.

Carbohydrate-containing nanoparticles as vaccine adjuvants.

Introduction: Adjuvants are essential to vaccines for immunopotentiation in the elicitation of protective immunity. However, classical and widely used aluminum-based adjuvants have limited capacity to induce cellular response. There are increasing needs for appropriate adjuvants with improved profiles for vaccine development toward emerging pathogens. Carbohydrate-containing nanoparticles (NPs) with immunomodulatory activity and particulate nanocarriers for effective antigen presentation are capable of eliciting a more balanced humoral and cellular immune response.Areas covered: We reviewed several carbohydrates with immunomodulatory properties. They include chitosan, ß-glucan, mannan, and saponins, which have been used in vaccine formulations. The mode of action, the preparation methods, characterization of these carbohydrate-containing NPs and the corresponding vaccines are presented.Expert opinion: Several carbohydrate-containing NPs have entered the clinical stage or have been used in licensed vaccines for human use. Saponin-containing NPs are being evaluated in a vaccine against SARS-CoV-2, the pathogen causing the on-going worldwide pandemic. Vaccines with carbohydrate-containing NPs are in different stages of development, from preclinical studies to late-stage clinical trials. A better understanding of the mode of action for carbohydrate-containing NPs as vaccine carriers and as immunostimulators will likely contribute to the design and development of new generation vaccines against cancer and infectious diseases.

Temporal association between human upper respiratory and gut bacterial microbiomes during the course of COVID-19 in adults.

SARS-CoV-2 is the cause of COVID-19. It infects multiple organs including the respiratory tract and gut. Dynamic changes of regional microbiomes in infected adults are largely unknown. Here, we performed longitudinal analyses of throat and anal swabs from 35 COVID-19 and 19 healthy adult controls, as well as 10 non-COVID-19 patients with other diseases, by 16 S rRNA gene sequencing. The results showed a partitioning of the patients into 3-4 categories based on microbial community types (I-IV) in both sites. The bacterial diversity was lower in COVID-19 patients than healthy controls and decreased gradually from community type I to III/IV. Although the dynamic change of microbiome was complex during COVID-19, a synchronous restoration of both the upper respiratory and gut microbiomes from early dysbiosis towards late more diverse status was observed in 6/8 mild COVID-19 adult patients. These findings reveal previously unknown interactions between upper respiratory and gut microbiomes during COVID-19.

Characteristics of myocardial injury in severe and critical coronavirus disease 2019 patients and its effect on prognosis

Objective To analyze the characteristics and related risk factors of myocardial injury in severe and critical coronavirus disease 2019 (COVID-19) patients and their relationship with the prognosis. Methods The clinical data of severe and critical COVID-19 patients treated in General Hospital of Central Theater Command of PLA from Jan. 2020 to Mar. 2020 were collected. The patients were divided into non-myocardial injury group and myocardial injury group. The baseline data, clinical characteristics, auxiliary examination, treatment and prognosis were compared between the two groups, and the risk factors of myocardial injury and the effect on the prognosis of the severe and critical COVID-19 patients were analyzed. Results A total of 56 patients were included, with 22 in the non-myocardial injury group and 34 in the myocardial injury group. Patients were mostly male in both groups, and there was no significant difference in gender composition between the two groups (P>0.05). Compared with the non-myocardial injury group, the age of onset was significantly higher in the myocardial injury group (78.5[ 70.8, 89.0] years vs 56.5[ 50.3, 68.3] years, P<0.01), and the proportions of patients over 65 years old and combined with coronary heart disease were significantly greater (85.3%[ 29/34] vs 31.8%[ 7/22] and 38.2% [13/34] vs 9.1%[ 2/22], both P<0.05). In terms of symptoms, fever (87.5%, 49/56), cough (64.3%, 36/56) and fatigue (46.4%, 26/56) were the most common ones, and there were no significant differences between the two groups (all P>0.05). For the CT findings of the lungs, the proportion of patients having patch-like/plaque-like shadows and ground-glass opacities was significantly greater in the non-myocardial injury group versus the myocardial injury group (72.7%[ 16/22] vs 38.2%[ 13/34], χ2=6.364, P<0.05), and other signs were not significantly different between the two groups (P>0.05). Compared with the non-myocardial injury group, the levels of N-terminal pro-B-type natriuretic peptide, D-dimer, procalcitonin and IL-6 were significantly higher in the myocardial injury group (4 939.5[ 1 817.0, 9 450.3] pg/mL vs 612.5[ 301.0, 1 029.5] pg/mL, 4 386.5 [2 309.5, 9 635.3] ng/mL vs 850.5 [343.5, 2 333.8] ng/mL, 0.46 [0.23, 3.79] ng/mL vs 0.18 [0.13, 0.39] ng/mL, and 138.6 [41.9, 464.8] pg/mL vs 65.1[ 34.7, 99.3] pg/mL, respectively), and the differences were significant (all P<0.01). Multivariate logistic regression analysis showed that age≥65 years old (odds ratio[ OR] =18.62, 95% confidence interval[ CI] 1.61-215.96, P<0.05) and D-dimer level≥3 000 ng/mL (OR=15.48, 95% CI 1.45-164.77, P<0.05) were the independent risk factors for myocardial injury in severe and critical COVID-19 patients. There were no significant differences in the use of antiviral drugs, antibacterial drugs, or glucocorticoids between the two groups (all P>0.05). The mortality rate was significantly higher in the myocardial injury than that in the non-myocardial injury group (58.8% [20/34] vs 9.1% [2/22], P<0.01). Patients who received tracheal intubation, extracorporeal membrane oxygenation, continuous renal replacement therapy (CRRT) and other invasive life support measures were all in the myocardial injury group. Conclusion Older age, male gender, coronary heart disease and (or) cardiac insufficiency, and elevated D-dimer, procalcitonin and IL-6 are the risk factors of myocardial injury in severe and critical COVID-19 patients. Myocardial injury can aggravate the condition and some patients need invasive circulating breathing support, with poor prognosis and high mortality. Therefore, the above indicators need to be observed more closely and dynamically and active treatment should be given according to related factors.

Zoonotic origins of human coronavirus 2019 (HCoV-19 / SARS-CoV-2): why is this work important?

The ongoing pandemic of coronavirus disease 2019 (COVID-19), caused by infection with human coronavirus 2019 (HCoV-19 / SARS-CoV-2 / 2019-nCoV), is a global threat to the human population. Here, we briefly summarize the available data for the zoonotic origins of HCoV-19, with reference to the other two epidemics of highly virulent coronaviruses, SARS-CoV and MERS-CoV, which cause severe pneumonia in humans. We propose to intensify future efforts for tracing the origins of HCoV-19, which is a very important scientific question for the control and prevention of the pandemic.

Probable Pangolin Origin of SARS-CoV-2 Associated with the COVID-19 Outbreak.

An outbreak of coronavirus disease 2019 (COVID-19) caused by the 2019 novel coronavirus (SARS-CoV-2) began in the city of Wuhan in China and has widely spread worldwide. Currently, it is vital to explore potential intermediate hosts of SARS-CoV-2 to control COVID-19 spread. Therefore, we reinvestigated published data from pangolin lung samples from which SARS-CoV-like CoVs were detected by Liu et al. [1]. We found genomic and evolutionary evidence of the occurrence of a SARS-CoV-2-like CoV (named Pangolin-CoV) in dead Malayan pangolins. Pangolin-CoV is 91.02% and 90.55% identical to SARS-CoV-2 and BatCoV RaTG13, respectively, at the whole-genome level. Aside from RaTG13, Pangolin-CoV is the most closely related CoV to SARS-CoV-2. The S1 protein of Pangolin-CoV is much more closely related to SARS-CoV-2 than to RaTG13. Five key amino acid residues involved in the interaction with human ACE2 are completely consistent between Pangolin-CoV and SARS-CoV-2, but four amino acid mutations are present in RaTG13. Both Pangolin-CoV and RaTG13 lost the putative furin recognition sequence motif at S1/S2 cleavage site that can be observed in the SARS-CoV-2. Conclusively, this study suggests that pangolin species are a natural reservoir of SARS-CoV-2-like CoVs.