Feature extraction of motor imagery electroencephalography based on time-frequency-space domains / 生物医学工程学杂志

The purpose of using brain-computer interface (BCI) is to build a bridge between brain and computer for the disable persons, in order to help them to communicate with the outside world. Electroencephalography (EEG) has low signal to noise ratio (SNR), and there exist some problems in the traditional methods for the feature extraction of EEG, such as low classification accuracy, lack of spatial information and huge amounts of features. To solve these problems, we proposed a new method based on time domain, frequency domain and space domain. In this study, independent component analysis (ICA) and wavelet transform were used to extract the temporal, spectral and spatial features from the original EEG signals, and then the extracted features were classified with the method combined support vector machine (SVM) with genetic algorithm (GA). The proposed method displayed a better classification performance, and made the mean accuracy of the Graz datasets in the BCI Competitions of 2003 reach 96%. The classification results showed that the proposed method with the three domains could effectively overcome the drawbacks of the traditional methods based solely on time-frequency domain when the EEG signals were used to describe the characteristics of the brain electrical signals.

Research on the performance comparing and building of affective computing database based on physiological parameters / 生物医学工程学杂志

The validity and reasonableness of emotional data are the key issues in the cognitive affective computing research. Effects of the emotion recognition are decided by the quality of selected data directly. Therefore, it is an important part of affective computing research to build affective computing database with good performance, so that it is the hot spot of research in this field. In this paper, the performance of two classical cognitive affective computing databases, the Massachusetts Institute of Technology (MIT) cognitive affective computing database and Germany Augsburg University emotion recognition database were compared, their data structure and data types were compared respectively, and emotional recognition effect based on the data were studied comparatively. The results indicated that the analysis based on the physical parameters could get the effective emotional recognition, and would be a feasible method of pressure emotional evaluation. Because of the lack of stress emotional evaluation data based on the physiological parameters domestically, there is not a public stress emotional database. We hereby built a dataset for the stress evaluation towards the high stress group in colleges, candidates of postgraduates of Ph. D and master as the subjects. We then acquired their physiological parameters, and performed the pressure analysis based on this database. The results indicated that this dataset had a certain reference value for the stress evaluation, and we hope this research can provide a reference and support for emotion evaluation and analysis.

Antibiotics Resistance of Staphylococcus aureus Isolated from Nosocomial Infection Patients and Detection of Resistance Genes / 中华医院感染学杂志

OBJECTIVE To investigate the antibiotics resistance and the presence of resistant gene of Staphylococcus aureus isolated from nosocomial infection patients in our hospital.METHODS Antibiotic susceptibility tests were conducted by Microscan WalkAway-40,the antibiotics resistant genes of aac(6')/aph(2″),aph(3')-Ⅲ,ant(4',4″),TEM,tetM,macA,erm and qacA/B of 16 MRSA and 24 MSSA strains were detected by PCR.RESULTS The percentage of MRSA in this investigation was 59.4%,the positive rate of ?-lactamases of 192 S.aureus strains was 98.9%,resistant rate of S.aureus to ?-lactam antibiotics was 52.1-99.0%,and to erythromycin,clindamycin,clarithromycin,ciprofloxacin,norfloxacin,gentamicin and tetracycline was 52.1%,78.1%,85.5%,56.3%,61.1%,55.2%,and 69.8%,respectively,but to nitrofurantoin and sulfamethoxazole/trimethoprim were relatively lower(1.1% and 10.5%) than the others.VISA,h-VISA and VRSA were not measured.To the most of antibiotics,the resistant rate of MRSA was higher than MSSA.The presence of resistant gene of MRSA and MSSA was different.There was more positive percentage of gene in MRSA than in MSSA.CONCLUSIONS Antibiotics resistance of S.aureus isolated from nosocomial infection patients in our hospital is severe.Compared to MSSA,MRSA has higher antibiotic resistant rate and more complicated drug-resistant mechanism.Some measures should be done to reduce the antibiotic resistance of S.aureus.

Genotyping of SCCmec and Detection of Antibiotic-resistant Genes in Meticillin-resistant Staphylococcus aureus / 中华医院感染学杂志

OBJECTIVE To investigate the staphylococcal cassette chromosome mec(SCCmec) genotype characteristics and antibiotic-resistant genes in meticillin-resistant Staphylococcus aureus(MRSA) isolated from Lianyungang.METHODS The SCCmec of clinically isolated MRSA strains were genotyped with a novel multiplex PCR strategy reported by Zhangetal.Antibiotic-resistant genes of aac(6′)/aph(2″),aph(3′)Ⅲ,tetM,erm,TEM,and ant(4′,4″) were analyzed by traditional PCR.RESULTS The isolates were almost SCCmec Ⅲ positve,only one isolate couldn′t be typed.The positive rates of aac(6′)/aph(2″),aph(3′)Ⅲ,tetM,and erm were 98%,46%,72% and 86%,respectively.TEM and ant(4′,4″) tested were all negative.CONCLUSIONS Almost all genotypes of MRSA prevailing in Lianyungang carry the SCCmec Ⅲ gene.There are high positive percentages of antibiotic-resistant genes of aac(6′)/aph(2″),aph(3′)Ⅲ,tetM and erm in the isolates.The novel multiplex PCR strategy recommended by Zhang et al can be applied into genotyping study of MRSA SCCmec effectively.