Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of coronavirus disease 2019 (COVID-19), emerged in China in December 2019 and quickly spread around the globe, killing more ...than 4 million people and causing a severe economic crisis. This extraordinary situation prompted entities in government, industry, and academia to work together at unprecedented speed to develop safe and effective vaccines. Indeed, vaccines of multiple types have been generated in record time, and many have been evaluated in clinical trials. Of these, messenger RNA (mRNA) vaccines have emerged as lead candidates due to their speed of development and high degree of safety and efficacy. To date, two mRNA vaccines have received approval for human use, providing proof of the feasibility of this next-generation vaccine modality. This review gives a detailed overview about the types of mRNA vaccines developed for SARS-CoV-2, discusses and compares preclinical and clinical data, gives a mechanistic overview about immune responses generated by mRNA vaccination, and speculates on the challenges and promising future of this emergent vaccine platform.
Efficient photocatalysis requires multifunctional materials that absorb photons and generate energetic charge carriers at catalytic active sites to facilitate a desired chemical reaction. ...Antenna–reactor complexes are an emerging multifunctional photocatalytic structure where the strong, localized near field of the plasmonic metal nanoparticle (e.g., Ag) is coupled to the catalytic properties of the nonplasmonic metal nanoparticle (e.g., Pt) to enable chemical transformations. With an eye toward sustainable solar driven photocatalysis, we investigate how the structure of antenna–reactor complexes governs their photocatalytic activity in the light-limited regime, where all photons need to be effectively utilized. By synthesizing core@shell/satellite (Ag@SiO2/Pt) antenna–reactor complexes with varying Ag nanoparticle diameters and performing photocatalytic CO oxidation, we observed plasmon-enhanced photocatalysis only for antenna–reactor complexes with antenna components of intermediate sizes (25 and 50 nm). Optimal photocatalytic performance was shown to be determined by a balance between maximized local field enhancements at the catalytically active Pt surface, minimized collective scattering of photons out of the catalyst bed by the complexes, and minimal light absorption in the Ag nanoparticle antenna. These results elucidate the critical aspects of local field enhancement, light scattering, and absorption in plasmonic photocatalyst design, especially under light-limited illumination conditions.
Tropical cyclones are increasing in intensity and size and, thus, are poised to increase in importance as disturbance agents. Our understanding of cyclone ecology is biased towards the North Atlantic ...Basin, because cyclone effects do differ across oceanic basins. Cyclones have both short and long-term effects across the levels of biological organization, but we lack a scale‐perspective of cyclone ecology. Effects on individual trees, such as defoliation or branch stripping and uprooting, are mechanistically linked to effects at the community and ecosystem levels, including forest productivity and stand regeneration time. Forest dwarfing via the gradual removal of taller trees by cyclones over many generations illustrates that cyclones shape forest structure through the accumulation of short-term effects over longer timescales.
Our understanding of cyclone ecology is biased toward the Atlantic Basin, but cyclone effects on forests differ among oceanic basins because of differences in storm frequency and strength.Projected increases in cyclone frequency, intensity, and geographic distribution will threaten the tall old trees of the world, especially those in old-growth forests, which historically have few cyclones, such as those in the southeastern USA and southern Japan.Cyclone effects on ecosystem processes, such as primary productivity and nutrient cycling, are mediated through the range of direct disturbance effects on individuals and species, such as defoliation and tree mortality.Forest dwarfing, because of the gradual removal of tall trees by individual cyclones, illustrates the accumulative short-term effects of individual cyclones on shaping long-term forest structure.
In this paper, data from spaceborne radar, lidar and infrared radiometers on the “A‐Train” of satellites are combined in a variational algorithm to retrieve ice cloud properties. The method allows a ...seamless retrieval between regions where both radar and lidar are sensitive to the regions where one detects the cloud. We first implement a cloud phase identification method, including identification of supercooled water layers using the lidar signal and temperature to discriminate ice from liquid. We also include rigorous calculation of errors assigned in the variational scheme. We estimate the impact of the microphysical assumptions on the algorithm when radiances are not assimilated by evaluating the impact of the change in the area‐diameter and the density‐diameter relationships in the retrieval of cloud properties. We show that changes to these assumptions affect the radar‐only and lidar‐only retrieval more than the radar‐lidar retrieval, although the lidar‐only extinction retrieval is only weakly affected. We also show that making use of the molecular lidar signal beyond the cloud as a constraint on optical depth, when ice clouds are sufficiently thin to allow the lidar signal to penetrate them entirely, improves the retrieved extinction. When infrared radiances are available, they provide an extra constraint and allow the extinction‐to‐backscatter ratio to vary linearly with height instead of being constant, which improves the vertical distribution of retrieved cloud properties.
Aqueous solutions containing light-absorbing nanoparticles have recently been shown to produce steam at high efficiencies upon solar illumination, even when the temperature of the bulk fluid volume ...remains far below its boiling point. Here we show that this phenomenon is due to a collective effect mediated by multiple light scattering from the dispersed nanoparticles. Randomly positioned nanoparticles that both scatter and absorb light are able to concentrate light energy into mesoscale volumes near the illuminated surface of the liquid. The resulting light absorption creates intense localized heating and efficient vaporization of the surrounding liquid. Light trapping-induced localized heating provides the mechanism for low-temperature light-induced steam generation and is consistent with classical heat transfer.
The rational combination of plasmonic nanoantennas with active transition metal-based catalysts, known as 'antenna-reactor' nanostructures, holds promise to expand the scope of chemical reactions ...possible with plasmonic photocatalysis. Here, we report earth-abundant embedded aluminum in cuprous oxide antenna-reactor heterostructures that operate more effectively and selectively for the reverse water-gas shift reaction under milder illumination than in conventional thermal conditions. Through rigorous comparison of the spatial temperature profile, optical absorption, and integrated electric field enhancement of the catalyst, we have been able to distinguish between competing photothermal and hot-carrier driven mechanistic pathways. The antenna-reactor geometry efficiently harnesses the plasmon resonance of aluminum to supply energetic hot-carriers and increases optical absorption in cuprous oxide for selective carbon dioxide conversion to carbon monoxide with visible light. The transition from noble metals to aluminum based antenna-reactor heterostructures in plasmonic photocatalysis provides a sustainable route to high-value chemicals and reaffirms the practical potential of plasmon-mediated chemical transformations.Plasmon-enhanced photocatalysis holds promise for the control of chemical reactions. Here the authors report an Al@Cu
O heterostructure based on earth abundant materials to transform CO
into CO at significantly milder conditions.
Control technologies to inactivate airborne viruses effectively are needed during the ongoing SARS-CoV-2 pandemic, and to guard against airborne transmitted diseases. We demonstrate that sealed UV–C ...flow reactors operating with fluences near 253 ± 1 nm of 13.9–49.6 mJ cm–2 efficiently inactivate coronaviruses in an aerosol. For measurements, porcine respiratory coronavirus (PRCV) was nebulized in a custom-built, 3.86 m wind tunnel housed in a biosafety level class II facility. The single pass log10 reduction of active coronavirus was in excess of 2.2 at a flow rate of 2439 L min–1 (13.9 mJ cm–2) and in excess of 3.7 (99.98% removal efficiency) at 684 L min–1 (49.6 mJ cm–2). Because virus titers resulting from sampling downstream of the UV–C reactor were below the limit of detection, the true log reduction is likely even higher than measured. Comparison of virus titration results to reverse transcriptase quantitative PCR and measurement of fluorescein concentrations (doped into the nebulized aerosol) reveals that the reduction in viable PRCV is primarily due to UV–C based inactivation, as opposed to physical collection of virus. The results confirm that UV–C flow reactors can efficiently inactivate coronaviruses through incorporation into HVAC ducts or recirculating air purifiers.
A simplified design procedure for foundations of offshore wind turbines is often useful as it can provide the types and sizes of foundation required to carry out financial viability analysis of a ...project and can also be used for tender design. This paper presents a simplified way of carrying out the design of monopiles based on necessary data (i.e. the least amount of data), namely site characteristics (wind speed at reference height, wind turbulence intensity, water depth, wave height and wave period), turbine characteristics (rated power, rated wind speed, rotor diameter, cut-in and cut-out speed, mass of the rotor-nacelle-assembly) and ground profile (soil stiffness variation with depth and soil stiffness at one diameter depth). Other data that may be required for final detailed design are also discussed. A flowchart of the design process is also presented for visualisation of the rather complex multi-disciplinary analysis. Where possible, validation of the proposed method is carried out based on field data and references/guidance are also drawn from codes of practice and certification bodies. The calculation procedures that are required can be easily carried out either through a series of spreadsheets or simple hand calculations. An example problem emulating the design of foundations for London Array wind farm is taken to demonstrate the proposed calculation procedure. The data used for the calculations are obtained from publicly available sources and the example shows that the simplified method arrives at a similar foundation to the one actually used in the project.
•Step by step methodology for monopile design.•Flowchart of the whole design process highlighting interdependency.•Long term tilt calculation shown.•Foundation flexibility and dynamics considered.
Gene set analysis methods are widely used to provide insight into high-throughput gene expression data. There are many gene set analysis methods available. These methods rely on various assumptions ...and have different requirements, strengths and weaknesses. In this paper, we classify gene set analysis methods based on their components, describe the underlying requirements and assumptions for each class, and provide directions for future research in developing and evaluating gene set analysis methods.
Innate immune mechanisms of mRNA vaccines Verbeke, Rein; Hogan, Michael J.; Loré, Karin ...
Immunity (Cambridge, Mass.),
11/2022, Letnik:
55, Številka:
11
Journal Article
Recenzirano
Odprti dostop
The lipid nanoparticle (LNP)-encapsulated, nucleoside-modified mRNA platform has been used to generate safe and effective vaccines in record time against COVID-19. Here, we review the current ...understanding of the manner whereby mRNA vaccines induce innate immune activation and how this contributes to protective immunity. We discuss innate immune sensing of mRNA vaccines at the cellular and intracellular levels and consider the contribution of both the mRNA and the LNP components to their immunogenicity. A key message that is emerging from recent observations is that the LNP carrier acts as a powerful adjuvant for this novel vaccine platform. In this context, we highlight important gaps in understanding and discuss how new insight into the mechanisms underlying the effectiveness of mRNA-LNP vaccines may enable tailoring mRNA and carrier molecules to develop vaccines with greater effectiveness and milder adverse events in the future.
Lipid nanoparticle-encapsulated, nucleoside-modified mRNA vaccines produce adaptive immune responses protective against COVID-19. Here, Pardi and colleagues review the innate immune-sensing pathways of this vaccine modality and discuss research directions that may yield a next generation of mRNA vaccines with improved immunogenicity and reduced reactogenicity.
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