Syphilis is a sexually transmitted disease caused by T. pallidum, and the T. pallidum Nichols strain is widely used with the New Zealand white rabbit model for evaluating drug and vaccine protection. However, changes in the virulence of T. pallidum during transmission are still unknown. Herein, we explored the virulence of T. pallidum in the rabbit model of continuous infection through phenotype observation and further investigated the relationship between virulence and adhesion. During the construction of the syphilis rabbit model, the optimal dose of 10 4 /site of T. pallidum was determined to effectively observe the depiction of syphilis lesions and immune responses for further virulence evaluation. Its virulence was gradually weakened during the interaction with host cells or the testicular passage, which was also proven using the pathological phenotype of the syphilis rabbit model. In addition, the adhesive ability of T. pallidum was reduced with increasing generation, which was verified via the co-incubation of the pathogen with Sf1Ep cells. This study provides insight into the relationship by which the virulence and adhesion of T. pallidum were decreased in a New Zealand white rabbit model of continuous infection and contributes to our knowledge regarding the development of syphilis.
Syphilis caused by Treponema pallidum (T. pallidum), is associated with the oxidative stress due to its inflammation-like symptom, and detecting the reactive oxygen species (ROS) is crucial for monitoring the...
Artemisinin has immunomodulatory, anti-inflammatory, and antifibrotic effects. Some studies have demonstrated that artemisinins have a protective effect on the kidney. DHA is a derivative of artemisinin and has effects similar to those of artemisinin. Human bone marrow-derived mesenchymal stem cells (BMSCs) accelerate renal repair following acute injury. In the study, we investigated the effects of combination therapy with DHA and BMSCs on membranous nephropathy (MN) mice. The 24-h urinary protein, serum total cholesterol (TC) and triglyceride (TG) levels, and renal histopathology, were measured to evaluate kidney damage. Anti-PLA2R, IgG, and complement 3 (C3) were detected by ELISA. The expression levels of the podocyte injury-related proteins were analyzed by immunohistochemistry. The protein expression levels of
α
-SMA, ED-1, TGF-
β
1, p-Smad2, and p-Smad3 were detected by western blot to analyze renal fibrosis and its regulatory mechanism. Results showed that combination therapy with DHA and BMSCs significantly ameliorated kidney damage in MN model mice by decreasing the levels of 24 h urinary protein, TC and TG. This combination therapy also improved renal histology and reduced the expression of IgG and C3 in the glomerulus. In addition, this combination therapy decreased the expression of podocin and nephrin and relieved renal fibrosis by downregulating
α
-SMA and ED-1. Furthermore, this combination therapy suppressed TGF-
β
1 expression and Smad2/3 phosphorylation. This result (i.e., this combination therapy inhibited the TGF-
β
1/Smad pathway) was also supported
in vitro
. Taken together, combination therapy with DHA and BMSCs ameliorated podocyte injury and renal fibrosis in MN mice by downregulating the TGF
β
1/Smad pathway.
In this paper, a concise leader-follower formation control approach is presented for a group of underactuated unmanned surface vehicle with dynamic system uncertainties and external environment disturbances, where the output errors are required to be within constraints. To settle the output error constraints, a standard barrier Lyapunov function (BLF) is incorporated into the backstepping control method. Furthermore, the “differential explosion” problem of virtual control laws is avoided by introducing the dynamic surface control. To estimate the unknown dynamic terms, an adaptive neural network is designed and a nonlinear disturbance observer is adopted to compensate for the approximation errors of neural network and ocean environment disturbances. Under the constraint of output error, the presented controller based on standard BLF has simpler structure and better control performance than depended on tan-type BLF. The presented controller can ensure that the formation errors converge to a small range around zero, while the output error constraint requirements are met. All signals in the closed-loop system are bounded, and the numerical simulation further shows the effectiveness of the presented control scheme.
In this paper, a leader–follower formation control strategy is presented based on adaptive neural network and disturbance observer, which is aimed at resolving model uncertainties as well as the time-varying disturbances for autonomous underactuated surface vessels. The model uncertainties which can be expressed by unknown nonlinear functions are approximated and compensated by the adaptive neural network. The disturbance observer introduced can estimate time-varying disturbances and compensate them to the feedforward control loop, so as to make the external time-varying disturbances suppressed and the robustness of controller against the disturbances improved. The dynamic surface control technology is applied in the procedure of designing the controller through utilizing the backstepping method, which solves the computational explosion of the derivative of virtual control signals. Finally, through Lyapunov analysis, the stability of adaptive neural formation control system is proved and all the error signals uniformly converge to a very small range ultimately. The excellent performance of the presented formation control strategy is demonstrated through numerical simulations.
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