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find Author "GAOShan" 3 results
  • Implementation of V1 Area Contour Integration Mechanism and Attention Selection Based on Excitation-Inhibition Intersecting Cortical Model

    This paper aims to utilize the intersecting cortical model (ICM), which imitates the biological neural cells sync pulse, to preliminary research about the contour integration mechanism and the selection of attention. The idea of "Excitement-Inhibition" oscillation is introduced into the ICM, and meanwhile, the target contour chain code is used as the high-level feedback to control the input. Thus, we propose the Excitation-Inhibition-ICM which contains both the BUTTON-UP and the TOP-DOWN mechanism. The experimental results showed that the proposed model could effectively suppress noise to make the smooth edge synchronization issue, thus completing the process of BOTTOM-UP. The introduction of the target contour chain code can obtain consistent target outline with the input target chain code, but other targets cannot form a closed contour since they do not match with the input target chain code, so as to realize the TOP-DOWN mechanism. The results proved that our proposed model could imitate the contour integration mechanism and the selection of attention of the visual cortex V1.

    Release date:2016-10-24 01:24 Export PDF Favorites Scan
  • Technical Research of Non-contact Electrocardiogram Based on Capacitive Coupling

    Based on the capacitance coupling principle, we studied a capacitive way of non-contact electrocardiogram (ECG) monitoring, making it possible to obtain ECG on the condition that a patient is habilimented. Conductive fabric with a good electrical conductivity was used as electrodes. The electrodes fixed on a bed sheet is presented in this paper. A capacitance comes into being as long as the body gets close to the surface of electrode, sandwiching the cotton cushion, which acts as dielectric. The surface potential generated by heart is coupled to electrodes through the capacitance. After being processed, the signal is suitable for monitoring. The test results show that 93.5% of R wave could be detected for 9 volunteers and ECG with good signal quality could be acquired for 2 burnt patients. Non-contact ECG is harmless to skin, and it has advantages for those patients to whom stickup electrodes are not suitable. On the other hand, it is convenient to use and good for permanent monitoring.

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  • T Cell Factor 4, β-catenin and SFRP1 Expression of Wnt Signaling Pathway in Colorectal Carcinoma and the Prognosis

    Abnormal activation of Wnt signaling pathway is closely related to the occurrence of tumor, and T cell factor 4 (Tcf4) and β-catenin are important signal transmission factors of this pathway. The aim of the present study is to explore the significance and correlation between expression of Tcf4, β-catenin and secreted frizzled related protein 1(SFRP1), suppressor gene of Wnt signaling pathway, in colorectal carcinoma and their correlations to the clinicopathological factors. The expressions of Tcf4, β-catenin and SFRP1 were performed with immunohistochemistry staining in 97 cases of primary colorectal carcinoma and 40 cases of normal colorectal mucosa tissues. The results showed that the abnormal expression rates of Tcf4 and β-catenin in colorectal carcinoma were significantly higher than those in the control groups (P<0.01). The positive rate of SFRP1 was significantly lower than those in the control groups (P<0.01). The abnormal expression rates of Tcf4 and β-catenin were also related to the lymph node metastasis and Dukes stage (P<0.05). A significant correlation was found between the expressions of SFRP1 and Tcf4, β-catenin (P<0.05). Over-expression of Tcf4 and β-catenin was related to poor prognosis (P<0.05). But the survival rates of the group with SFRP1 expressions were higher than those in group without SFRP1 expressions (P<0.05). Cox multifactor regression analysis indicated that Dukes stage, expression of β-catenin and SFRP1 were independent risk factors of colorectal carcinoma (P<0.05). The results suggested that the abnormal expression of Tcf4 and β-catenin in colorectal cancer may be related to the reduced or absent expression of SFRP1. β-catenin accumulation in the nuclei formed complexes with Tcf4 is one of the important molecular switch maintaining colorectal malignant phenotype. The combined detection of these indexes may perform an important role in predicting the progression and prognosis of colorectal cancer, and could provide new molecular targets for gene treatment of colorectal cancer.

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