Robust Average Formation Tracking for Multi-Agent Systems With Multiple Leaders

In this paper, the formation tracking problem of the multi-agent system under disturbances and unmodeled uncertainties has been studied. An identifier-based robust control algorithm using the neighboring relative information has been proposed to ensure the followers to maintain a given, and time-varying formation and track the average state of the leaders at the same time. Some sufficient conditions for the second-order multi-agent system with multiple leaders in the presence of disturbances and unmodeled uncertainties have been proposed based on the graph theory and the Lyapunov method. Numerical simulations are provided to testify the validity of the algorithm

Memory-Enhancing Effects of the Crude Extract of Polygala tenuifolia on Aged Mice.

Learning and memory disorders arise from distinct age-associated processes, and aging animals are often used as a model of memory impairment. The root of Polygala tenuifolia has been commonly used in some Asian countries as memory enhancer and its memory improvement has been reported in various animal models. However, there is less research to verify its effect on memory functions in aged animals. Herein, the memory-enhancing effects of the crude extract of Polygala tenuifolia (EPT) on normal aged mice were assessed by Morris water maze (MWM) and step-down passive avoidance tests. In MWM tests, the impaired spatial memory of the aged mice was partly reversed by EPT (100 and 200 mg/kg; P < 0.05) as compared with the aged control mice. In step-down tests, the nonspatial memory of the aged mice was improved by EPT (100 and 200 mg/kg; P < 0.05). Additionally, EPT could increase superoxide dismutase (SOD) and catalase (CAT) activities, inhibit monoamine oxidase (MAO) and acetyl cholinesterase (AChE) activities, and decrease the levels of malondialdehyde (MDA) in the brain tissue of the aged mice. The results showed that EPT improved memory functions of the aged mice probably via its antioxidant properties and via decreasing the activities of MAO and AChE.Peer Reviewe

Memory-Enhancing Effects of the Crude Extract of Polygala tenuifolia on Aged Mice.

Learning and memory disorders arise from distinct age-associated processes, and aging animals are often used as a model of memory impairment. The root of Polygala tenuifolia has been commonly used in some Asian countries as memory enhancer and its memory improvement has been reported in various animal models. However, there is less research to verify its effect on memory functions in aged animals. Herein, the memory-enhancing effects of the crude extract of Polygala tenuifolia (EPT) on normal aged mice were assessed by Morris water maze (MWM) and step-down passive avoidance tests. In MWM tests, the impaired spatial memory of the aged mice was partly reversed by EPT (100 and 200 mg/kg; P < 0.05) as compared with the aged control mice. In step-down tests, the nonspatial memory of the aged mice was improved by EPT (100 and 200 mg/kg; P < 0.05). Additionally, EPT could increase superoxide dismutase (SOD) and catalase (CAT) activities, inhibit monoamine oxidase (MAO) and acetyl cholinesterase (AChE) activities, and decrease the levels of malondialdehyde (MDA) in the brain tissue of the aged mice. The results showed that EPT improved memory functions of the aged mice probably via its antioxidant properties and via decreasing the activities of MAO and AChE

Phase interrogation SPR sensing based on white light polarized interference for wide dynamic detection range

A phase surface plasmon resonance (SPR) sensing technology based on white light polarized interference in common-path geometry is reported. A halogen lamp is used as the excitation source of the SPR sensor. The fixed optical path difference (OPD) between p- and s-polarized light is introduced by a birefringence crystal to produce sinusoidal spectral interference fringes. The SPR phase is accurately extracted from the interference fringes using a novel iterative parameter-scanning cross-correlation algorithm. The dynamic detection range is expanded by tracking the best SPR wavelength, which is identified using a window Fourier algorithm. The experimental results show that the sensitivity of this SPR system was 1.3 × 10−7 RIU, and the dynamic detection range was 0.029 RIU. This sensor, not only simple to implement and cost efficient, requires no modulators

High-throughput imaging surface plasmon resonance biosensing based on ultrafast two-point spectral-dip tracking scheme

Wavelength interrogation surface plasmon resonance imaging (λSPRi) has potential in detecting 2-dimensional (2D) sensor array sites, but the resonance wavelength imaging rate limits the application of detecting biomolecular binding process in real time. In this paper, we have successfully demonstrated an ultrafast λSPRi biosensor system. The key feature is a two-point tracking algorithm that drives the liquid crystal tunable filter (LCTF) to achieve fast-tracking of the resonance wavelength movement caused by the binding of target molecules with the probe molecules on the sensing surface. The resonance wavelength measurement time is within 0.25s. To date, this is the fastest speed ever reported in λSPRi. Experiment results show that the sensitivity and dynamic are 2.4 × 10−6 RIU and 4.6 × 10−2 RIU, respectively. In addition, we have also demonstrated that the system has the capability of performing fast high-throughput detection of biomolecular interactions, which confirms that this fast real-time detecting approach is most suitable for high-throughput and label-free biosensing applications

CD100 up-Regulation Induced by Interferon-α on B Cells Is Related to Hepatitis C Virus Infection

Objectives: CD100, also known as Sema4D, is a member of the semaphorin family and has important regulatory functions that promote immune cell activation and responses. The role of CD100 expression on B cells in immune regulation during chronic hepatitis C virus (HCV) infection remains unclear. Materials and Methods: We longitudinally investigated the altered expression of CD100, its receptor CD72, and other activation markers CD69 and CD86 on B cells in 20 chronic HCV-infected patients before and after treatment with pegylated interferon-alpha (Peg-IFN-α) and ribavirin (RBV) by flow cytometry. Results: The frequency of CD5+ B cells as well as the expression levels of CD100, CD69 and CD86 was significantly increased in chronic HCV patients and returned to normal in patients with sustained virological response after discontinuation of IFN-α/RBV therapy. Upon IFN-α treatment, CD100 expression on B cells and the two subsets was further up-regulated in patients who achieved early virological response, and this was confirmed by in vitro experiments. Moreover, the increased CD100 expression via IFN-α was inversely correlated with the decline of the HCV-RNA titer during early-phase treatment. Conclusions: Peripheral B cells show an activated phenotype during chronic HCV infection. Moreover, IFN-α therapy facilitates the reversion of disrupted B cell homeostasis, and up-regulated expression of CD100 may be indirectly related to HCV clearance

Phase interrogation surface plasmon resonance hyperspectral imaging sensor for multi-channel high-throughput detection

Phase interrogation surface plasmon resonance (SPR) imaging is, in principle, suitable in multiple samples and high-throughput detection, but the refractive index difference of various samples can be largely varied, while the dynamic range of phase interrogation SPR is narrow. So it is difficult to perform multi-sample detection in phase interrogation mode. In this paper, we successfully designed a multi-channel phase interrogation detection SPR imaging sensing scheme based on a common optical interference path between p- and s-polarized light without using any mechanical moving components. The fixed optical path difference between p- and s-polarized light is introduced by a birefringence crystal to produce sinusoidal spectral interference fringes. We adopted a time-division-multiplexing peak-finding algorithm to track the resonance wavelength so that the detection range can cover every channel. The phase values which carry the high sensitivity signal of the corresponding samples are calculated by the iterative parameter scanning cross-correlation algorithm

Corrigendum: High-Sensitive Surface Plasmon Resonance Imaging Biosensor Based on Dual-Wavelength Differential Method

[This corrects the article DOI: 10.3389/fchem.2021.801355.]