9 research outputs found

    ESO-Based Fuzzy Sliding-Mode Control for a 3-DOF Serial-Parallel Hybrid Humanoid Arm

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    This paper presents a unique ESO-based fuzzy sliding-mode controller (FSMC-ESO) for a 3-DOF serial-parallel hybrid humanoid arm (HHA) for the trajectory tracking control problem. The dynamic model of the HHA is obtained by Lagrange method and is nonlinear in dynamics with inertia uncertainty and external disturbance. The FSMC-ESO is based on the combination of the sliding-mode control (SMC), extended state observer (ESO) theory, and fuzzy control (FC). The SMC is insensitive to both internal parameter uncertainties and external disturbances. The motivation for using ESO is to estimate the disturbance in real-time. The fuzzy parameter self-tuning strategy is proposed to adjust the switching gain on line according to the running state of the system. The stability of the system is guaranteed in the sense of the Lyapunov stability theorem. The effectiveness and robustness of the designed FSMC-ESO are illustrated by simulations

    ERCC4: a potential regulatory factor in inflammatory bowel disease and inflammation-associated colorectal cancer

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    The pathogenesis of inflammatory bowel disease (IBD) remains unclear and is associated with an increased risk of developing colitis-associated cancer (CAC). Under sustained inflammatory stimulation in the intestines, loss of early DNA damage response genes can lead to tumor formation. Many proteins are involved in the pathways of DNA damage response and play critical roles in protecting genes from various potential damages that DNA may undergo. ERCC4 is a structure-specific endonuclease that participates in the nucleotide excision repair (NER) pathway. The catalytic site of ERCC4 determines the activity of NER and is an indispensable gene in the NER pathway. ERCC4 may be involved in the imbalanced process of DNA damage and repair in IBD-related inflammation and CAC. This article primarily reviews the function of ERCC4 in the DNA repair pathway and discusses its potential role in the processes of IBD-related inflammation and carcinogenesis. Finally, we explore how this knowledge may open novel avenues for the treatment of IBD and IBD-related cancer

    A Feed-Forward Regulatory Loop between HuR and the Long Noncoding RNA HOTAIR Promotes Head and Neck Squamous Cell Carcinoma Progression and Metastasis

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    Background/Aims: The lncRNA Homeobox (HOX) transcript antisense RNA (HOTAIR) is overexpressed in numerous cancers. HuR is also overexpressed during tumourigenesis and is abnormally present within the cytoplasm, where it binds to AU-rich elements in the 3′UTRs of target mRNA and post-transcriptionally regulates the expression of its target genes. However, whether HOTAIR is regulated and the mechanisms by which it affects head and neck squamous cell carcinoma (HNSCC) are not well understood. Methods: MTT, cell cycle arrest and apoptotic assays were used to examine the effects of HOTAIR and HuR on cell viability in SCC25 and FaDu cells. Wound healing and transwell invasion analysis were performed to detect the effects of HOTAIR and HuR on cell migration and invasion. The interaction between HuR and HOTAIR was confirmed via qRT-PCR, western blots, luciferase reporter and RIP assays. Finally, qRT-PCR analysis was used to detect the levels of HuR and HOTAIR in HNSCC tumours and adjacent normal tissues. Results: Knockdown of HOTAIR and HuR decreased cell viability, cellular migration and invasion. Moreover, HuR interacted and stabilized HOTAIR stability and thus promoted HOTAIR expression. Notably, HOTAIR acted as a miRNA sponge for HuR. HuR also reinforced HOTAIR sponge activity through miRNA recruitment, thus enhancing HuR expression in turn. Finally, HuR and HOTAIR levels were positively correlated and significantly up-regulated in tumours samples. Conclusion: We demonstrated the existence of a regulatory loop in which the expression of HOTAIR and HuR is reciprocally and temporally regulated during the metastasis and progression of HNSCC

    Image Stabilization in Central Vision Loss: The Horizontal Vestibulo-Ocular Reflex

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    For patients with central vision loss and controls with normal vision, we examined the horizontal vestibulo-ocular reflex (VOR) in complete darkness and in the light when enhanced by vision (VVOR). We expected that the visual-vestibular interaction during VVOR would produce an asymmetry in the gain due to the location of the preferred retinal locus (PRL) of the patients. In the dark, we hypothesized that the VOR would not be affected by the loss of central vision. Nine patients (ages 67 to 92 years) and 17 controls (ages 16 to 81 years) were tested in 10-s active VVOR and VOR procedures at a constant frequency of 0.5 Hz while their eyes and head movements were recorded with a video-based binocular eye tracker. We computed the gain by analyzing the eye and head peak velocities produced during the intervals between saccades. In the light and in darkness, a significant proportion of patients showed larger leftward than rightward peak velocities, consistent with a PRL to the left of the scotoma. No asymmetries were found for the controls. These data support the notion that, after central vision loss, the preferred retinal locus (PRL) in eccentric vision becomes the centre of visual direction, even in the dark

    Self-Paced Saccades in Patients with Concussion

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    Currently there are no diagnostic measures that can predict which patients with concussion will develop post-concussion syndrome (PCS). In a previous study we showed that higher symptom burden and alterations in white-matter integrity are associated with impairment in the control of self-paced saccades in patients with PCS. Previous studies suggest that this impairment will improve over a short time period in some PCS patients but some will continue to demonstrate eye movement abnormalities. Identifying patients with sustained impairment to their eye movements including self-paced control system can help predict those patients that will develop PCS
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