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FimH is the adhesin of type I fimbriae expressed on Escherichia coli that can mediate specific adherence to host cells. High binding mutations in FimH are related to the adaptive evolution of bacteria. However, additional roles that these allelic variations may play remain elusive. To investigate novel biological functions of the mutations in FimH, we introduced four different variants of FimH by incorporating single amino acid substitutions at specific sites, namely A25P, G73R, A106, and T158P, respectively. In this study, adjuvant potential of FimH variants was evaluated by investigating their ability to trigger innate immune response to DC2.4 and adaptive immunity to improve immunological characteristics. The data revealed that purified A106 and T158P up-regulated the expression of co-stimulatory molecules critically involved in DC2.4 activation by interaction with TLR4, whereas A25P and G73R did not induce the phenotypic maturation of DC2.4. Besides, the culture of DC2.4 with A106 and T158P enhanced the release of cytokines and protein phagocytosis. When formulated with PAc, T158P elicited more robust PAc-specific IgG and IgA antibody responses compared to PBS, PAc and PAc+K12 groups and inhibited bacteria colonization. Collectively, the results confirmed that the T158P mutation located around the inter-domain interface of the protein induced a specific enhancement effect on adjuvant characteristics.

The problem of multiplicative passive control for a class of uncertain sampled-data systems with time-delay is considered via observer-based control, aiming to solve the problem that many kinds of uncertainties in the plant, controller and observer. In the light of the Lyapunov stability theory and linear matrix inequality (LMI) approach, a sufficient existence condition and design method of observer and multiplicative passive controller are derived. Finally, a numerical example is illustrated to show the effectiveness of the proposed results.

The parameter values such as stator resistance, stator inductance, permanent magnet flux and moment of inertia for permanent magnet synchronous motor (PMSM) are of great significance to the controller design. During the operation of PMSM, these parameter values will change due to the influence of temperature and other external factors. In order to obtain these parameter values in real time, this paper put forward an online identification method based on the combination of extended Kalman filter and gradient correction. The simulation results show that the online identification method can obtain PMSM parameter values quickly and accurately. The method has a certain guiding significance for the design controller of PMSM.

We previously demonstrated that recombinant protein PAc could be administered as an anticaries vaccine. However, the relatively weak immunogenicity of PAc limits its application. In the present study, we investigated the effect of two adjuvant combinations of chitosan plus Pam3CSK4 (chitosan-Pam3CSK4) and of chitosan plus monophosphoryl lipid A (chitosan-MPL) in the immune responses to the PAc protein in vivo and in vitro PAc-chitosan-Pam3CSK4 or PAc-chitosan-MPL promoted significantly higher PAc-specific antibody titers in serum and saliva, inhibited Streptococcus mutans colonization onto the tooth surfaces, and endowed better protection effect with significantly less caries activities than PAc alone. Chitosan-Pam3CSK4 and chitosan-MPL showed no statistically significant differences. In conclusion, our study demonstrated that the chitosan-Pam3CSK4 and chitosan-MPL combinations are promising for anticaries vaccine development.

Active disturbance rejection control (ADRC) is an emerging robust control technology. It can compensate the modeling error effectively, parameter perturbation and environmental disturbance of the airborne photoelectric platform, thus to improve the stability and tracking accuracy of the photoelectric platform. The application of ADRC in the speed stabilization loop of photoelectric platform is introduced in this paper. In addition, an alternative ADRC is initially applied to the speed stabilization loop of photoelectric platform. The alternative ADRC is constructed based on partially known model information. The alternative ADRC has better disturbance rejection capacity than the traditional ADRC. In the field of photoelectric platform, simulation results show robustness, effectiveness and feasibleness of alternative ADRC.

The problem of observer-based on robust control of a class of welding process systems is considered. According to unknown state of the welding system, design method of observer is provided. In the process of solving observer gain and control gain, Lyapunov theory and Linear matrix inequalities are combined. Finally, a numerical example is illustrated to show the effectiveness of the proposed results.

Non-fragile load frequency control scheme is provided to solve the problem of multi-area power system with energy storage system and wind power. A dynamical model is established in term of multi-area power system with time-delay and uncertainties, which subjects to circular pole constraints simultaneously. Firstly, it is convenient to be operated by computer, the discrete-time signal is attained by sampling the dynamical model, which results in that long time-delay is equivalently turned into two pairs of successive state time-delay. Secondly, non-fragile control is employed to guarantee the closed-loop poles of the equivalent discrete-time one locate in the specified circular region inside the unit disk. Besides, the specified circular region can be transformed into the unit disk by the appropriate linear transformation, thereby, D-stabilization is converted into asymptotical stabilization. Thirdly, the direct distributed scheme of time-delay is adopted, in comparison with the state augmented scheme, less computational burden is derived. Finally, numerical examples are put forward to verify the effectiveness of the proposed methods.

Streptococcus mutans often survives as a biofilm on the tooth surface and contributes to the development of dental caries. We investigated the efficacy of ClyR, an engineered chimeolysin, against S. mutans biofilms under physiological and cariogenic conditions. Susceptibility tests showed that ClyR was active against all clinical S. mutans isolates tested as well as S. mutans biofilms that displayed resistance to penicillin. The S. mutans biofilms that formed on hydroxyapatite discs under physiological sugar conditions and cariogenic conditions were reduced ∼2 logs and 3 logs after treatment with 100 μg/ml ClyR, respectively. In comparison, only a 1-log reduction was observed in the chlorhexidine gluconate (ChX)-treated group, and no killing effect was observed in the NaF-treated group. A mouse dental colonization model showed that repeated use of ClyR for 3 weeks (5 μg/day) reduced the number of colonized S. mutans cells in the dental plaques significantly ( P < 0.05) and had no harmful effects on the mice. Furthermore, toxicity was not noted at concentrations exceeding those used for the in vitro and in vivo studies, and ClyR-specific antibodies could not be detected in mouse saliva after repeated use of ClyR in the oral cavity. Our data collectively demonstrate that ClyR is active against S. mutans biofilms both in vitro and in vivo , thus representing a preventative or therapeutic agent for use against dental caries.

The problem of additive H ∞ control for a class of uncertain sampled-data systems with time-delay is considered via observer-based state feedback control. According to the case that there exist uncertainties not only in the plant, but also in controller gains and observer gains, and in terms of the Lyapunov function theory and linear matrix inequality (LMI) approach, a sufficient condition on the existence and designing method of non-fragile observer and additive H ∞ controller are derived. Finally, a numerical example is illustrated to show the effectiveness of the proposed results.

The welding process is one of the most important application in uncertain sampled-data system. In this paper, the study deals with a fundamental issue of non-fragile control for a class of uncertain sampled-data system. The focus is to design non-fragile controller against possible perturbation by combining pole contraints theory and the linear matrix inequality approach which results in sampled-data system is D-stable, moreover, the existence condition and the design approach of non-fragile controller are derived. Finally, simulation examples are proposed to demonstrate the effectiveness of the attained algorithm.

This paper investigates robust control for a class of sampled-data system with long time-delay. The control input is subject to long time-delay, and the state includes norm-bounded perturbation, which roots in the process of model establishing. Moreover, the direct distribution method of long time-delay is adopted to design robust controller which ensures robust stability and satisfies a preset performance index for sampled-data system. The proposed stability condition is given in the light of LMI, an illustrative numerical example is provided to show effectiveness and feasibility.

We are concerned with the stabilization control problem for a class of systems with random switchings and state jumps. We suppose the random switching signal to obey Poisson distribution and intend to use output-feedback control to achieve stabilization. Firstly, based on the statistic property of the distribution of switching points, we derive some sufficient conditions to guarantee the closed-loop system to be almost surely exponentially stable. Then, we pose a parametrization approach to convert the construction conditions of the output-feedback control into a family of matrix inequalities.

This paper mainly studies the problem of the robust stability analysis for sampled-data system with long time delay. By constructing an improved Lyapunov-Krasovskii functional and employing some free weighting matrices, some new robust stability criteria can be established in terms of linear matrix inequalities. Furthermore, the proposed equivalent criterion eliminates the effect of free weighing matrices such that numbers of decision variables and computational burden are less than some existing results. A numerical example is also presented and compared with previously proposed algorithm to illustrate the feasibility and effectiveness of the developed results.