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The COVID‐19 pandemic highlighted the clear risk that zoonotic viruses pose to global health and economies. The scientific community responded by developing several efficacious vaccines which were expedited by the global need for vaccines. The emergence of SARS‐CoV‐2 breakthrough infections highlights the need for additional vaccine modalities to provide stronger, long‐lived protective immunity. Here we report the design and preclinical testing of small extracellular vesicles (sEVs) as a multi‐subunit vaccine. Cell lines were engineered to produce sEVs containing either the SARS‐CoV‐2 Spike receptor‐binding domain, or an antigenic region from SARS‐CoV‐2 Nucleocapsid, or both in combination, and we tested their ability to evoke immune responses in vitro and in vivo. B cells incubated with bioengineered sEVs were potent activators of antigen‐specific T cell clones. Mice immunised with sEVs containing both sRBD and Nucleocapsid antigens generated sRBD‐specific IgGs, nucleocapsid‐specific IgGs, which neutralised SARS‐CoV‐2 infection. sEV‐based vaccines allow multiple antigens to be delivered simultaneously resulting in potent, broad immunity, and provide a quick, cheap, and reliable method to test vaccine candidates. [ABSTRACT FROM AUTHOR]

The antiviral restriction factor, tetherin, blocks the release of several different families of enveloped viruses, including the Coronaviridae. Tetherin is an interferon‐induced protein that forms parallel homodimers between the host cell and viral particles, linking viruses to the surface of infected cells and inhibiting their release. We demonstrate that SARS‐CoV‐2 infection causes tetherin downregulation and that tetherin depletion from cells enhances SARS‐CoV‐2 viral titres. We investigate the potential viral proteins involved in abrogating tetherin function and find that SARS‐CoV‐2 ORF3a reduces tetherin localisation within biosynthetic organelles where Coronaviruses bud, and increases tetherin localisation to late endocytic organelles via reduced retrograde recycling. We also find that expression of Spike protein causes a reduction in cellular tetherin levels. Our results confirm that tetherin acts as a host restriction factor for SARS‐CoV‐2 and highlight the multiple distinct mechanisms by which SARS‐CoV‐2 subverts tetherin function. Synopsis: The anti‐viral restriction factor Tetherin blocks the egress of SARS‐CoV‐2. Expression of ORF3a and Spike protein antagonises tetherin to allow SARS‐CoV‐2 escape.Tetherin loss aids SARS‐CoV‐2 viral spread.SARS‐CoV‐2 ORF3a alters tetherin localization by impairing retrograde traffic and enhances virus release.SARS‐CoV‐2 Spike causes tetherin downregulation. [ABSTRACT FROM AUTHOR]

We propose a new duty-ratio feedforward controller for the flyback inverter with a synchronous rectifier (SR) circuit. For grid-connected photovoltaic power systems, the power factor (PF) of the output current must be high under most of the load conditions. To improve the PF of the flyback inverter even under light load, we propose a compensation method for the output capacitor current. The proposed method improves the displacement factor as well as the distortion factor, so the flyback inverter with the SR circuit has high power quality. By means of the SR circuit, the flyback inverter can operate in reverse when the negative current is required. The derivation of the proposed method is presented based on time-domain analysis. We also provide the boundary of the region where the proposed scheme should be adopted. The effectiveness of the proposed method is demonstrated in experiments with a 120-W rated power prototype. [ABSTRACT FROM AUTHOR]

This paper proposes a repetitive controller with phase-lead compensation for an unfolding-type Cuk continuous conduction mode (CCM) inverter operating in the CCM. The Cuk CCM inverter features medium power capacity, step up/down ability, and low input/output current ripples, so it is well suited to distributed power generation systems. To achieve accurate tracking of the reference output current, we make the use of the repetitive controller coupled with a conventional proportional-integral controller and a nominal duty ratio. In developing the proposed controller, we use the average model of the Cuk CCM inverter in the grid-connected case. The two right-half plane (RHP) zeros in the transfer function of the Cuk CCM inverter cause phase lag of the closed-loop system; to compensate for the phase lag, we implement a phase-lead compensation algorithm in the repetitive control scheme. We also provide detailed and practical design guidelines of the control parameters to develop a stable Cuk CCM inverter. Experimental tests using a 500-W Cuk CCM inverter demonstrate the desirable performance of the proposed control approach. [ABSTRACT FROM PUBLISHER]

In this paper, we propose a Lyapunov-function-based controller for the flyback converter operating in the continuous conduction mode (CCM). The controller consists of a duty-ratio feedforward control unit and a Lyapunov-function-based feedback control unit. The duty-ratio feedforward signal is used to reduce the burden from the Lyapunov feedback controller. The control system guarantees global exponential stability of the closed-loop system and, hence, offers fast transient response under large-signal perturbations. In constructing the controller, we use the average model of the flyback CCM converter taking the parasitic components into account. Numerical simulations confirmed its superior performance, and experimental tests validated the proposed control approach. [ABSTRACT FROM PUBLISHER]

We propose a downsampled iterative learning controller (ILC) for a flyback inverter operating in continuous conduction mode (CCM). The flyback CCM inverter features step-up/-down ability, small number of circuit components, and high conversion efficiency, so it is well suited to the distributed renewable energy systems. But the conventional proportional-integral (PI) controller for the flyback CCM inverter shows poor steady-state response because the inverter itself suffers from time-varying grid-voltage disturbances and its transfer function has a right-half plane zero. The ILC itself achieves acceptable steady-state response of the flyback CCM inverter but can excite large overshoot in the iteration domain; this overshoot may destroy the solid state devices in the power circuit. To overcome this problem, we use a downsampled ILC technique that guarantees monotonic convergence of tracking error. The proposed ILC is computationally simple and easy to implement. Numerical simulations and experimental tests validate the proposed control approach. [ABSTRACT FROM PUBLISHER]

This paper presents adaptive time-delay control (TDC) with a supervising switching technique (SST) for controlling robot manipulators. Two adaptive techniques are used to enhance the TDC. The control gain of TDC is adaptively tuned using a class of Nussbaum functions. With Nussbaum functions, compared with conventional TDC using a constant gain, the proposed control using Nussbaum functions can deal with inertia parameter variations due to the movement of a robot manipulator. The SST is used to deal with discontinuous disturbances. The proposed control is model-free, highly accurate, robust and adaptive. [ABSTRACT FROM AUTHOR]