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ObjectivesEven though disinfectants are commonly used in clinical practice and daily life, there are few studies on their antibacterial ability and cytotoxicity, which are closely related to the safety and effectiveness of their use. To provide a basis for the use of disinfectants, the cytotoxicity and antibacterial activity of three most commonly used disinfectants, povidone-iodine, chlorhexidine acetate and polyhexamethylene biguanide (PHMB), were investigated.DesignA CCK-8 assay was used to measure the activities of human fibroblasts (HF) and keratinocytes (HaCat), the two most important cells in wound healing, following their exposure to disinfectants. The effects of different times and concentrations were included. The antibacterial activity of disinfectants againstStaphylococcus aureus, Acinetobacter baumannii, Klebsiella pneumoniaewas reflected by their minimum inhibitory concentration and minimum bactericidal concentration.ResultsAll three disinfectants showed strong cytotoxicity in direct contact with HF and HaCat cells. Cytotoxicity increased with increasing exposure time and concentration.S. aureus,A. baumannii and K. pneumoniaecomprised 70%, 55% and 85% of the strains sensitive to povidone iodine; 50%, 45% and 80% of the strains sensitive to chlorhexidine acetate; and 60%, 45% and 80% of the strains sensitive to PHMB, respectively.ConclusionsAll three disinfectants were cytotoxic; therefore, it is necessary to pay attention to the use time and concentration in the clinical setting. All three disinfectants were cytotoxic, with povidone-iodine being the most cytotoxic even at low concentrations. PHMB had better antibacterial efficacy againstS. aureusand is suitable for the treatment of shallow wounds primarily. All three tested bacteria were significantly more sensitive to PHMB than to the other disinfectants.

Burns cause a loss of skin barrier function, rendering it prone to infection. The prevention of infection comprises a focus on the treatment of patients with burns. Therefore, we analysed the results of microbiological tests of patients with severe and extremely severe burns to provide a basis for the prevention and treatment of infection in patients with burns. The results of microbiological tests of patients with severe and extremely severe burns admitted to our burn centre between 2009 and 2019 were retrospectively reviewed. The overall positive rate of microbial detection was 40.67% and did not significantly decline over the 10-year study period. The most common positive sites were wounds, sputum, and urine. The most common bacterial species causing the infections were Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Furthermore, the predictors of a positive detection, overall and at various sites, mainly included the burn area and depth, inhalation injury, and length of the hospital stay. Positive detection was an important predictor of the prognosis. In particular, a positive blood culture and Klebsiella pneumoniae had better predictive strength for mortality than other sites and strains. This study analysed the microbiological testing results at a single burn centre over a period of 10 years. The results provide information regarding the predictors of a positive detection and the influence of a positive detection on prognosis, and can be used as a basis for the development of clinical infection prevention and treatment strategies, as well as the selection of treatment measures.

A large number of animal experiments show that there is irregular chaos in the biological nervous systems. An artificial chaotic neural network is a highly nonlinear dynamic system, which can realize a series of complex dynamic behaviors, optimize global search and neural computation, and generate pseudo-random sequences for information encryption. According to the superposition theory of sinusoidal signals with different frequencies of brain waves, a non-monotone activation function based on the multifrequency-frequency conversion sinusoidal function and a piecewise function is proposed to make a neural network more consistent with the biological characteristics. The analysis shows that by adjusting the parameters, the activation function can exhibit the EEG signals in its different states, which can simulate the rich and varying brain activities when the brain waves of different frequencies and types work at the same time. According to the activation function we design a new chaotic cellular neural network. The complexity of the chaotic neural network is analyzed by the structural complexity based SE algorithm and C0 algorithm. By means of Lyapunov exponential spectrum, bifurcation diagram and basin of attraction, the effects of the activation function’s parameters on its dynamic characteristics are analyzed in detail, and it is found that a series of complex phenomena appears in the chaotic neural network, such as many different types of chaotic attractors, coexistent chaotic attractors and coexistence limit cycles, which improves the performance of the chaotic neural network, and proves that the multi-frequency sinusoidal chaotic neural network has rich dynamic characteristics, so it has a good prospect in information processing, information encryption and other aspects.

Memristor, memcapacitor and meminductor are novel nonlinear circuit elements with memory, which are also known as the memory elements. Based on the mathematical models of these three circuit elements, from the point of view of mathematical analysis, memristor, memcapacitor and meminductor Simulink based models are established. Simulink models of the memory elements reflect that their values are dependent on their historical states and their state variables, and correctly show their unique memory properties. A series of simulation analyses are done, and the typical characteristics of the three memory elements are obtained, showing the validities of these models. In addition, by studying the circuit characteristics under different parameters and excitations, the changing laws of these equivalent models with frequency and amplitude are obtained, which lay the foundation for research and application based on memristor, memcapacitor and meminductor's Simulink simulator.

Based on two modified Rosslor hyperchaotic systems, which are derived from the chaotic Rosslor system by introducing a state feedback controller, this paper proposes a new switched Rosslor hyperchaotic system. The switched system contains two different hyperchaotic systems and can change its behaviour continuously from one to another via a switching function. On the other hand, it presents a systematic method for designing the circuit of realizing the proposed hyperchaotic system. In this design, circuit state equations are written in normalized dimensionless form by rescaling the time variable. Furthermore, an analogous circuit is designed by using the proposed method and built for verifying the new hyperchaos and the design method. Experimental results show a good agreement between numerical simulations and experimental results.

In this paper, a new four-dimensional autonomous hyperchaotic system is designed for generating complex chaotic signals. In the design, its parameters are selected according to the requirements for chaos and hyperchaos. The hyperchaotic Nature is verified theoretically by using the bifurcation analysis and demonstrated experimentally by the implementation of an analogue electronic circuit. Moreover, the Field Programmable Gate Array (FPGA) technology is applied to implementing a continuous system in a digital form by using a chip of Altera Cyclone II EP2C35F484C8. The digital sequence generated from the FPGA device is observed in our experimental setup.