ICOS-ICOSL pathway enhances NKT-like cell antiviral function in pregnant women with COVID-19.

Objective: The immune response initiated by SARS-CoV-2 infection in pregnancy is poorly elucidated. We aimed to access and compare the antiviral cellular responses and lymphocytes activation between healthy pregnancies and pregnant women infected with SARS-CoV-2. Methods: We detected the immunological changes of lymphocytes in peripheral blood of healthy non-pregnant women, non-pregnant women with COVID-19, healthy pregnant women, pregnant women with COVID-19 and convalescent group by flow cytometry. In vitro blockade was used to identify NKT-like cell activation through ICOS-ICOSL pathway. Results: We found that CD3+CD56+ NKT-like cells decreased significantly in COVID-19 positive pregnant women compared to healthy pregnant women. NKT-like cells of pregnant women expressed higher level of activating receptors CD69 and NKp46 after SARS-CoV-2 infection. Particularly, they also increased the expression of the co-stimulatory molecule ICOS. NKT-like cells of pregnant women with COVID-19 up-regulated the expression of IFN-γ, CD107a and Ki67. Meanwhile, we found that ICOSL expression was significantly increased on pDCs in pregnant women with COVID-19. Blocking ICOS in vitro significantly decreased the antiviral activity of NKT-like cells in COVID-19 positive pregnant women, suggesting that ICOS-ICOSL may play an important role in the virus clearance by NKT-like cells. Conclusions: During SARS-CoV-2 infection, NKT-like cells of pregnant women activated through ICOS-ICOSL pathway and played an important role in the antiviral response.

Restoration of CD3+CD56+ NKT-like cell function by TIGIT blockade in inactive carrier and immune tolerant patients of chronic hepatitis B virus infection.

Chronic hepatitis B (CHB) virus infection, which can be divided into immune-tolerant (IT), immune-active (IA), inactive carrier (IC) phases, and HBeAg-negative hepatitis (ENEG), can induce liver cirrhosis and eventually hepatocellular carcinoma (HCC). CD3+CD56+ NKT-like cells play an important role in antiviral immune response. However, the mechanism of NKT-like cells to mediate immune tolerance remains largely elusive. In this study, we observed circulating NKT-like cells from IC and IT CHB patients were phenotypically and functionally impaired, manifested by increased expression of inhibitory receptor TIGIT and decreased capacity of secreting antiviral cytokines. Besides, TIGIT+ NKT-like cells of IC and IT CHB patients expressed lower levels of cytotoxic cytokines than the TIGIT- subset. Furthermore, increased expression of CD155, the ligand of TIGIT, on plasmacytoid dendritic cells (pDCs) was detected in IC and IT CHB patients. Importantly, the co-culture of NKT-like cells and pDCs showed that NKT-like cells restored their antiviral ability after TIGIT blockade upon HBV peptide stimulation in IC and IT CHB patients. In conclusion, our findings suggest that the TIGIT pathway may mediate immune tolerance in IT CHB patients and lead to functional impairment in IC patients, indicating that TIGIT may be a potential therapeutic checkpoint for immunotherapy of CHB patients.

Consensus-based secondary control for DC microgrids with communication delays via a networked predictive control strategy.

In today's cyber-physical microgrid systems, the consensus-based secondary control is generally utilized to settle the voltage deviation and rough current allocation issues at the primary control level. However, time delays follow inevitably the introduction of sparse communication networks, and most existing works adopt passive tolerance approaches. To actively alleviate the unavoidable delay effect in microgrids' communication networks, a networked predictive control (NPC) strategy is proposed for an islanded DC microgrid subject to time delays in this paper. Firstly, the predictive approaches for both voltage and current are developed based on the cyber-physical microgrid model. Unlike the practice of passively tolerating time delays, the NPC strategy is proposed to actively compensate for the effect of communication delays by estimating real-time voltage and current values using the previously obtained prediction models. Moreover, to prove the generality of the developed method, the microgrid systems' stability can be derived from the Schur stability of the closed-loop system, thus the DC microgrid can achieve voltage regulation and proportional current sharing simultaneously. Finally, the performance of our method against the time delay effect is validated by extensive experiments on an islanded 48-V DC microgrid system, in terms of its feasibility, delay tolerance ability, and robustness to load changes and communication faults. Experimental results demonstrate the effectiveness and superiority of the NPC strategy.

Digital twin based monitoring and control for DC-DC converters.

The monitoring and control of DC-DC converters have become key issues since DC-DC converters are gradually playing increasingly crucial roles in power electronics applications such as electric vehicles and renewable energy systems. As an emerging and transforming technology, the digital twin, which is a dynamic virtual replica of a physical system, can potentially provide solutions for the monitoring and control of DC-DC converters. This work discusses the design and implementation of the digital twin DC-DC converter in detail. The key features of the physical and twin systems are outlined, and the control architecture is provided. To verify the effectiveness of the proposed digital twin method, four possible cases that may occur during the practical control scenarios of DC-DC converter applications are discussed. Simulations and experimental verification are conducted, showing that the digital twin can dynamically track the physical DC-DC converter, detect the failure of the physical controller and replace it in real time.