A Photoactivable Natural Product with Broad Antiviral Activity against Enveloped Viruses, Including Highly Pathogenic Coronaviruses.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak has highlighted the need for broad-spectrum antivirals against coronaviruses (CoVs). Here, pheophorbide a (Pba) was identified as a highly active antiviral molecule against human CoV-229E after bioguided fractionation of plant extracts. The antiviral activity of Pba was subsequently shown for SARS-CoV-2 and Middle East respiratory syndrome coronavirus (MERS-CoV), and its mechanism of action was further assessed, showing that Pba is an inhibitor of coronavirus entry by directly targeting the viral particle. Interestingly, the antiviral activity of Pba depends on light exposure, and Pba was shown to inhibit virus-cell fusion by stiffening the viral membrane, as demonstrated by cryoelectron microscopy. Moreover, Pba was shown to be broadly active against several other enveloped viruses and reduced SARS-CoV-2 and MERS-CoV replication in primary human bronchial epithelial cells. Pba is the first described natural antiviral against SARS-CoV-2 with direct photosensitive virucidal activity that holds potential for COVID-19 therapy or disinfection of SARS-CoV-2-contaminated surfaces.

Biomechanical Fidelity of Simulated Pick-and-Place Tasks: Impact of Visual and Haptic Renderings.

Virtual environments (VE) and haptic interfaces (HI) tend to be introduced as virtual prototyping tools to assess ergonomic features of workstations. These approaches are cost-effective and convenient since working directly on the Digital Mock-Up in a VE is preferable to constructing a physical mock-up in a Real Environment (RE). However it can be usable only if the ergonomic conclusions made from the VE are similar to the ones you would make in the real world. This article aims at evaluating the impact of visual and haptic renderings in terms of biomechanical fidelity for pick-and-place tasks. Fourteen subjects performed time-constrained pick-and-place tasks in RE and VE with a real and a virtual, haptic driven object at three different speeds. Motion of the hand and muscles activation of the upper limb were recorded. A questionnaire assessed subjectively discomfort and immersion. The results revealed significant differences between measured indicators in RE and VE and with real and virtual object. Objective and subjective measures indicated higher muscle activity and higher length of the hand trajectories in VE and with HI. Another important element is that no cross effect between haptic and visual rendering was reported. Theses results confirmed that such systems should be used with caution for ergonomics evaluation, especially when investigating postural and muscle quantities as discomfort indicators. The last contribution of the paper lies in an experimental setup easily replicable to asses more systematically the biomechanical fidelity of virtual environments for ergonomics purposes.

Oceanic vortex mergers are not isolated but influenced by the ß-effect and surrounding eddies.

Oceanic vortices are ubiquitous in the ocean. They dominate the sub-inertial energy spectrum, and their dynamics is key for the evolution of the water column properties. The merger of two like-signed coherent vortices, which ultimately results in the formation of a larger vortex, provides an efficient mechanism for the lateral mixing of water masses in the ocean. Understanding the conditions of such interaction in the ocean is thus essential. Here, we use a merger detection algorithm to draw a global picture of this process in the ocean. We show that vortex mergers are not isolated, contrary to the hypothesis made in most earlier studies. Paradoxically, the merging distance is well reproduced by isolated vortex merger numerical simulations, but it is imperative to consider both the ß-effect and the presence of neighbouring eddies to fully understand the physics of oceanic vortex merger.

Nonstructural protein NS1 immunodominant epitope detected specifically in dengue virus infected material by a SELDI-TOF/MS based assay.

Dengue virus (DV) infection is the most common mosquito-born viral disease of public health significance. Though most patients only suffer from flu-like symptoms, a small group of patients experiences more severe forms of the disease. The viral nonstructural protein 1 (NS1), a secreted protein correlating with viremia, is a key element used for dengue diagnosis with potential implications in severe dengue prognosis. Capture-ELISAs for the early detection of the NS1 protein in the sera during the acute febrile stage are commonly used in routine by diagnostic laboratories. In this study, the detection of NS1 protein in DV-infected material was assessed by an alternative method combining a single NS1-directed monoclonal antibody and the SELDI-TOF/MS technology. According to the epitope mapping, the antibodies used are mainly directed against an immuno-dominant peptide located on the C-terminal part of the protein. The NS1 SELDI-TOF assay is specific, has a sensitivity level close to capture-ELISAs and is potentially useful for a coupled serotyping/detection assay or for the detection of subtle post-translational modifications on the protein.