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This paper considers the global stabilization for a class of uncertain nonlinear systems with unknown powers, unknown control directions, and unknown nonlinearities. Mainly due to the presence of the unknown powers which have not known upper bound, no existing methods are applicable to the control problem to be solved. In this paper, to compensate the serious system uncertainties and particularly to overcome the major obstruction from unknown powers, we appeal to the mechanism of switching adaptive feedback. By flexibly combining the domination and the method of adding a power integrator, we propose a new adaptive controller design, whose design parameters are tuned online based on a switching logic. The designed controller will become operative as long as finite switchings happen and will not lead to Zeno phenomenon, and can guarantee the global boundedness as well as ultimate convergence of the resulting closed-loop system. Two numerical examples are given to demonstrate the effectiveness of the developed design scheme. [ABSTRACT FROM AUTHOR]

Asarinin is one of the main active chemical components isolated from Xixin, a Chinese medicine. To investigate the role of asarinin in rheumatoid arthritis (RA), the present study investigated the effect of an asarinin-medicated serum on human fibroblast-like synoviocytes in vitro. An asarinin-medicated serum was generated and analyzed by high-performance liquid chromatography. Fibroblast-like synoviocytes were isolated from patients with osteoarthritis and RA. The third generation of the rheumatoid synoviocytes was used in the experimental research and the third generation of osteoarthritic synoviocytes was used as control cells. Trypan blue staining was performed to detect the viability of RA synovial fibroblasts (RASFs). ELISA, reverse transcription-quantitative (RT-q) PCR and western blotting were also performed to detect the expression of various cytokines. Additionally, RT-qPCR was employed to detect Toll-like receptor (TLR) 2 and TLR4. The results revealed that medicated asarinin serum inhibited the viability of RASFs in a dose- and time-dependent manner. The serum also suppressed the expression of interleukin (IL)-17A, tumor necrosis factor-α, interferon-γ, IL-6, TLR2 and TLR4. The inhibitory effect of asarinin drug serum on RASFs may be achieved by inhibition of T helper cell (Th)1/Th17 cytokines through suppression of TLR2 and TLR4. [ABSTRACT FROM AUTHOR]

The recent development and mass administration of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) vaccines allowed for disease control, reducing hospitalizations and mortality. Most of these vaccines target the SARS-CoV-2 Spike (S) protein antigens, culminating with the production of neutralizing antibodies (NAbs) that disrupt the attachment of the virus to ACE2 receptors on the host cells. However, several studies demonstrated that the NAbs typically rise within a few weeks after vaccination but quickly reduce months later. Thus, multiple booster administration is recommended, leading to vaccination hesitancy in many populations. Detecting serum anti-SARS-CoV-2 NAbs can instruct patients and healthcare providers on correct booster strategies. Several in vitro diagnostics kits are available; however, their high cost impairs the mass NAbs diagnostic testing. Recently, we engineered an ACE2 mimetic that interacts with the Receptor Binding Domain (RBD) of the SARS-2 S protein. Here we present the use of this engineered mini-protein (p-deface2 mut) to develop a detection assay to measure NAbs in patient sera using a competitive ELISA assay. Serum samples from twenty-one patients were tested. Nine samples (42.8%) tested positive, and twelve (57.1%) tested negative for neutralizing sera. The data correlated with the result from the standard commercial assay that uses human ACE2 protein. This confirmed that p-deface2 mut could replace human ACE2 in ELISA assays. Using bacterially expressed p-deface2 mut protein is cost-effective and may allow mass SARS-CoV-2 NAbs detection, especially in low-income countries where economical diagnostic testing is crucial. Such information will help providers decide when a booster is required, reducing risks of reinfection and preventing the administration before it is medically necessary. [ABSTRACT FROM AUTHOR]