The world continues to face a life-threatening viral pandemic. The virus underlying the Coronavirus Disease 2019 (COVID-19), Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), has caused over 98 million confirmed cases and 2.2 million deaths since January 2020. Although the most recent respiratory viral pandemic swept the globe only a decade ago, the way science operates and responds to current events has experienced a cultural shift in the interim. The scientific community has responded rapidly to the COVID-19 pandemic, releasing over 125,000 COVID-19–related scientific articles within 10 months of the first confirmed case, of which more than 30,000 were hosted by preprint servers. We focused our analysis on bioRxiv and medRxiv, 2 growing preprint servers for biomedical research, investigating the attributes of COVID-19 preprints, their access and usage rates, as well as characteristics of their propagation on online platforms. Our data provide evidence for increased scientific and public engagement with preprints related to COVID-19 (COVID-19 preprints are accessed more, cited more, and shared more on various online platforms than non-COVID-19 preprints), as well as changes in the use of preprints by journalists and policymakers. We also find evidence for changes in preprinting and publishing behaviour: COVID-19 preprints are shorter and reviewed faster. Our results highlight the unprecedented role of preprints and preprint servers in the dissemination of COVID-19 science and the impact of the pandemic on the scientific communication landscape.

The sialidase (neuraminidase) inhibitor 4-guanidino-2,4-dideoxy-2,3-dehydro-N-acetylneuraminic acid (4-guanidino-Neu5Ac2en) has been examined for the ability to inhibit the growth of a wide range of influenza A The sialidase (neuraminidase, acylneuraminyl hydrolase, EC 3.2

A mutant of herpes simplex virus type 1, 17tsVP1201, has a temperaturesensitive processing defect in a late virus polypeptide. Immunoprecipitation studies with monoclonal antibodies showed that the aberrant polypeptide in mutant virus-infected cells was the nucleocapsid polypeptide known as p40. Since a revertant, TS' for growth, processed the polypeptide normally under conditions restrictive for the mutant, the processing event must be essential for virus replication. Electron microscopic analysis of mutant virus-infected cells grown at the nonpermissive temperature revealed that the nuclei contained large aggregations of empty nucleocapsids possessing some internal structure. Therefore, although the mutant synthesized virus DNA at the nonpermissive temperature, the DNA was not packaged into nucleocapsids. When mutant virus-infected cells were shifted from 39 to 31°C in the presence of cycloheximide, the polypeptide p40 was processed to lower-molecular-weight forms, and full nucleocapsids were detected in the cell nuclei. The aberrant polypeptide of the mutant, however, was not processed in cells mixedly infected with 17tsVP1201 and a revertant at the nonpermissive temperature, suggesting that the defect of the mutant was in the gene encoding p40 rather than in a gene of a processing enzyme.

Racemic 2'-deoxy-3'-thiacytidine (BCH 189) is a dideoxycytidine analog having a sulfur atom in place of the 3' carbon. The enantiomers of BCH 189 have been resolved and found to be equipotent in antiviral activity against human immunodeficiency virus types 1 and 2. However, the (-)-enantiomer (3TC) is considerably less cytotoxic than the (+)-enantiomer.

25The world continues to face an ongoing viral pandemic that presents a serious threat to human 26 health. The virus underlying the COVID-19 disease, SARS-CoV-2, has caused over 3.2 million confirmed 27 cases and 220,000 deaths between January and April 2020. Although the last pandemic of respiratory 28 disease of viral origin swept the globe only a decade ago, the way science operates and responds to 29 current events has experienced a paradigm shift in the interim. The scientific community has 30 responded rapidly to the COVID-19 pandemic, releasing over 16,000 COVID-19 related scientific 31 articles within 4 months of the first confirmed case, of which at least 6,000 were hosted by preprint 32 servers. We focused our analysis on bioRxiv and medRxiv, two growing preprint servers for biomedical 33 research, investigating the attributes of COVID-19 preprints, their access and usage rates, 34 characteristics of their sharing on online platforms, and the relationship between preprints and their 35 published articles. Our data provides evidence for increased scientific and public engagement (COVID-36 19 preprints are accessed and distributed at least 15 times more than non-COVID-19 preprints) and 37 changes in journalistic practice with reference to preprints. We also find evidence for changes in 38 preprinting and publishing behaviour: COVID-19 preprints are shorter, with fewer panels and tables, 39 and reviewed faster. Our results highlight the unprecedented role of preprints and preprint servers in 40 the dissemination of COVID-19 science, and the likely long-term impact of the pandemic on the 41 scientific publishing landscape. 42 43 44 45 46 47 48 49 50 51 52 53 54The first quarter of 2020 has been defined by the COVID-19 outbreak, which has escalated to 55 pandemic status, and caused over 3.2 million cases and 220,000 deaths within 4 months of the first 56 reported case [1,2]. The causative pathogen was rapidly identified as a novel virus within the family 57Coronaviridae and was named severe acute respiratory syndrome coronavirus 2 (or 'SARS-CoV-2') [3]. 58 Although multiple coronaviruses are ubiquitous among humans and cause only mild disease, 59 epidemics of newly emerging coronaviruses were previously observed in SARS coronavirus in 2002 [4] 60 and Middle East respiratory syndrome (MERS) coronavirus in 2012 [5]. The unprecedented extent and 61 rate of spread of COVID-19 has created a critical global health emergency and academic communities 62 have raced to actively respond through research developments. 63 Research developments have traditionally been communicated via published journal articles or 64 conference presentations. Traditional scientific publishing involves the submission of manuscripts to 65 an individual journal, which then organises peer review. Authors often conduct additional experiments 66or analyses to address the reviewers' concerns in one or more revisions. Even after this lengthy 67 process is concluded, almost half of submissions are rejected and require re-submission to a different ...

The (-)-enantiomer of 2'-deoxy-3'-thiacytidine (3TC) was found to be a potent and selective inhibitor of human immunodeficiency virus types 1 (HIV-1) and 2 (HIV-2) in vitro. We determined its antiviral activity against a number of laboratory strains of HIV-1 and HIV-2 in a range of CD4-bearing lymphocyte cell lines (mean 50% inhibitory concentration [IC50] range, 4 nM to 0.67 microM). 3TC was also active against a range of HIV-1 strains in peripheral blood lymphocytes (mean IC50 range, 2.5 to 90 nM). The IC50 for cytotoxicity in seven lymphocyte cell cultures, including human peripheral blood lymphocytes, ranged from 0.5 to 6 mM. 3TC had no detectable antiviral activity against a range of other viruses or in cells chronically infected with HIV-1 or HIV-2. The effects of time of addition of the compound and varying the multiplicity of infection on the antiviral activity of 3TC were determined. The results showed that 3TC is a potent and selective inhibitor of HIV-1 and HIV-2 replication in vitro.

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Amid the Coronavirus Disease 2019 (COVID-19) pandemic, preprints in the biomedical sciences are being posted and accessed at unprecedented rates, drawing widespread attention from the general public, press, and policymakers for the first time. This phenomenon has sharpened long-standing questions about the reliability of information shared prior to journal peer review. Does the information shared in preprints typically withstand the scrutiny of peer review, or are conclusions likely to change in the version of record? We assessed preprints from bioRxiv and medRxiv that had been posted and subsequently published in a journal through April 30, 2020, representing the initial phase of the pandemic response. We utilised a combination of automatic and manual annotations to quantify how an article changed between the preprinted and published version. We found that the total number of figure panels and tables changed little between preprint and published articles. Moreover, the conclusions of 7.2% of non-COVID-19–related and 17.2% of COVID-19–related abstracts undergo a discrete change by the time of publication, but the majority of these changes do not qualitatively change the conclusions of the paper.