A spike denoising method combined principal component analysis with wavelet and ensemble empirical mode decomposition / 生物医学工程学杂志

Spike recorded by multi-channel microelectrode array is very weak and susceptible to interference, whose noisy characteristic affects the accuracy of spike detection. Aiming at the independent white noise, correlation noise and colored noise in the process of spike detection, combining principal component analysis (PCA), wavelet analysis and adaptive time-frequency analysis, a new denoising method (PCWE) that combines PCA-wavelet (PCAW) and ensemble empirical mode decomposition is proposed. Firstly, the principal component was extracted and removed as correlation noise using PCA. Then the wavelet-threshold method was used to remove the independent white noise. Finally, EEMD was used to decompose the noise into the intrinsic modal function of each layer and remove the colored noise. The simulation results showed that PCWE can increase the signal-to-noise ratio by about 2.67 dB and decrease the standard deviation by about 0.4 μV, which apparently improved the accuracy of spike detection. The results of measured data showed that PCWE can increase the signal-to-noise ratio by about 1.33 dB and reduce the standard deviation by about 18.33 μV, which showed its good denoising performance. The results of this study suggests that PCWE can improve the reliability of spike signal and provide an accurate and effective spike denoising new method for the encoding and decoding of neural signal.

The utility of texture analysis in differential diagnosis of medulloblastomas and ependymomas / 实用放射学杂志

Objective To analyze magnetic resonance images of medulloblastomas and ependymomas by texture analysis method, and evaluate the texture characteristics of two tumors by support vector machine (SVM).Methods 58 tumors were analyzed retro-spectively,including 31 medulloblastomas and 27 ependymomas,which had been confirmed with operation and pathology.Texture analysis was performed onthese tumors.Results The 5 texture parameters extracted from the gray level co-occurrence matrix and at least 3 parameters which had statistical significance between the two different classes of data sets(P<0.05).For all data sets,the variance parameters of gray value of ROI region have statistical significance.The accuracy of SVM test was (86.15±4.16)%,which had remarkable significance between the ependymomas and medulloblastomas.Conclusion The analysis of texture features can pro-vide a lot of quantitative information,and can be a potential method for the differential diagnosis of medulloblastomas and ependy-momas.

The application value in diagnosis of chronic atrophic gastritis using the magnifying endoscopy and narrow-band imaging / 中国医师杂志

Objective To explore the application value in diagnosis of chronic atrophic gastritis using the magnifying endoscopy and narrow-band imaging.Methods A total of 98 cases of chronic atrophic gastritis patients was selected,and carried out the ordinary white light endoscopy,magnifying endoscopy and narrow-band imaging(ME-NBI) and pathological examination in file,followed by comparison of the results.Results The sensitivity and specificity of chronic atrophic gastritis by magnifying endoscopy and narrowband imaging mode were 74.07％ and 82.35％,respectively;which were significantly higher than that obtained by conventional endoscopy,which were 48.15％ and 64.71％ (P ＜0.05).In magnifying endoscopy and narrow-band imaging endoscopy group,60 patients were positive,which intestinal metaplasia accounted for 35％,while in conventional endoscopy group,39 patients were positive which was only 17.95％ (P ＜ 0.05).Conclusions Magnifying endoscopy and narrow-band imaging can improve the diagnostic accuracy of chronic atrophic gastritis.

Modeling and analysis of Schistosoma Argonaute protein molecular spatial conformation

Objective: To analyze the amino acid sequence composition, secondary structure, the spatial conformation of its domain and other characteristics of Argonaute protein. Methods:Bioinformatics tools and the internet server were used. Firstly, the amino acid sequence composition features of the Argonaute protein were analyzed, and the phylogenetic tree was constructed. Secondly, Argonaute protein’s distribution of secondary structure and its physicochemical properties were predicted. Lastly, the protein functional expression form of the domain group was established through the Phyre-based analysis on the spatial conformation of Argonaute protein domains. Results: 593 amino acids were encoded by Argonaute protein, the phylogenetic tree was constructed, and Argonaute protein’s distribution of secondary structure and its physicochemical properties were obtained through analysis. In addition, the functional expression form which comprised the N-terminal PAZ domain and C-terminal Piwi domain for the Argonaute protein was obtained with Phyre. Conclusions: The information relationship between the structure and function of the Argonaute protein can be initially established with bioinformatics tools and the internet server, and this provides the theoretical basis for further clarifying the function of Schistosoma Argonaute protein.

Modeling and analysis of Schistosoma Argonaute protein molecular spatial conformation

<p><b>OBJECTIVE</b>To analyze the amino acid sequence composition, secondary structure, the spatial conformation of its domain and other characteristics of Argonaute protein.</p><p><b>METHODS</b>Bioinformatics tools and the internet server were used. Firstly, the amino acid sequence composition features of the Argonaute protein were analyzed, and the phylogenetic tree was constructed. Secondly, Argonaute protein's distribution of secondary structure and its physicochemical properties were predicted. Lastly, the protein functional expression form of the domain group was established through the Phyre-based analysis on the spatial conformation of Argonaute protein domains.</p><p><b>RESULTS</b>593 amino acids were encoded by Argonaute protein, the phylogenetic tree was constructed, and Argonaute protein's distribution of secondary structure and its physicochemical properties were obtained through analysis. In addition, the functional expression form which comprised the N-terminal PAZ domain and C-terminal Piwi domain for the Argonaute protein was obtained with Phyre.</p><p><b>CONCLUSIONS</b>The information relationship between the structure and function of the Argonaute protein can be initially established with bioinformatics tools and the internet server, and this provides the theoretical basis for further clarifying the function of Schistosoma Argonaute protein.</p>