Search

Actuator faults usually cause security problem in practice. This paper is concerned with the security control of positive semi-Markovian jump systems with actuator faults. The considered systems are with mode transition-dependent sojourn-time distributions, which may also lead to actuator faults. First, the time-varying and bounded transition rate that satisfies the mode transition-dependent sojourn-time distribution is considered. Then, a stochastic co-positive Lyapunov function is constructed. Using matrix decomposition technique, a set of state-feedback controllers for positive semi-Markovian jump systems with actuator faults are designed in terms of linear programming. Under the designed controllers, stochastic stabilization of the systems with actuator faults are achieved and the security of the systems can be guaranteed. Furthermore, the proposed results are extended to positive semi-Markovian jump systems with interval and polytopic uncertainties. By virtue of a segmentation technique of the transition rates, a less conservative security control design is also proposed. Finally, numerical examples are provided to demonstrate the validity of the presented results.

In this paper, an ultrahigh sensitive hydrazine electrochemical sensor based on gold nanoparticles integrated into a reduced graphene oxide/nickel foam (AuNPs-rGO@NF) hybrid structure was synthesized using a facile coating and electrochemical deposition method. The morphology and elemental composition of the as-synthesized AuNPs-rGO@NF structure was comprehensively investigated. Both cyclic voltammetry and potential amperometry results show the optimum AuNPs-rGO@NF sensor exhibits excellent electrochemical performances including higher sensitivity (14.635 μA μM−1 cm−2), lower limit of detection (0.056 μM; S/N = 3), wider linear detection range (0.2–200 μM), good selectivity and long-term stability. Meanwhile, the results of real sample analysis indicate the AuNPs-rGO@NF sensor has great potential for practical electrochemical hydrazine sensing applications.

This paper proposes the robust model predictive control of positive time-delay systems with interval and polytopic uncertainties, respectively. The model predictive control framework consists of linear constraint, linear performance index, linear Lyapunov function, linear programming algorithm, and cone invariant set. By virtue of matrix decomposition technique, robust model predictive controllers of interval and polytopic positive systems with multiple state delays are designed, respectively. A multi step control strategy is utilized and a cone invariant set is constructed. Linear programming is used for the corresponding MPC conditions. Finally, a numerical example is given to verify the effectiveness of the proposed design.

Background Staphylococcus aureus is an important zoonotic pathogen which not only causes significant economic loss in livestock production but also poses a potential threat to public health. Compared with bovine and swine, the information on the colonization of S. aureus in goats is very limited. To understand the prevalence and characteristics of S. aureus in goats, we used the nasal swabs collected from apparently healthy goats to isolate S. aureus, and tested their antimicrobial susceptibility, virulence gene carrying levels, and multilocus sequence typing (MLST). Results In 74 nasal swabs of apparently healthy goats, 32 (43.24%) S. aureus strains were isolated and identified, most of which were susceptible to many antibiotics, except for trimethoprim, furazolidone, amoxicillin, lincomycin and roxithromycin, and the resistance incidence of which were 50%, 40.63%, 37.5%, 28.13%, and 21.88% respectively. All the isolates were methicillin-susceptible S. aureus (MSSA) and mecA-negative. Enterotoxin genes were found in 53.13% of the strains. Of which, sej was the most prevalent (21.88%), followed by seb, sec, and see with the same level (18.75%). The most prevalent combination were seb + see and seb + tst. None of the S. aureus isolates harbored sea, sed, seh, eta and etb. Multilocus sequence typing (MLST) revealed 6 new alleles (aroe-552, aroe-553, glpf-500, pta-440, yqil-482 and yqil-496) and 5 new sequence types (STs) (3431,3440,3444,3445 and 3461). Using eBURST, the 5 STs were assigned to clonal complex 522 (CC522) and a further CC with no predicted ancestor. Phylogenetic analysis of seven concatenated MLST alleles revealed that the 5 STs were grouped into cluster I composed of S. aureus mainly from goats and sheep. Conclusion We provide the data for prevalence of S. aureus in goats in Chongqing municipality and their characterization which will help in tracking evolution of epidemic strains and their control methods.

The amorphous phase/TiO2 nanocrystals (APTN) composited coatings were prepared on Ti implants for biomedical applications. The Ti implants without and with the APTN composited coatings both do not cause any adverse effects after implantation into the rabbit tibia. The osseointegration of Ti implants after covering the APTN coatings is improved pronouncedly, greatly increasing the interface bonding strength between the implants and newly formed bones. In addition, it is interesting that the newly formed bone tissues appear in the micro-pores of the APTN coatings, promoting the interface bonding between the implants and new bones by the mechanical interlock. Moreover, the Ti implant with the APTN coatings formed at higher applied voltage exhibit higher shear strength and displacement during the pushing out experiment probably due to its better osseointegration.