Increasing the amplitude of event-related potential is one of the key methods to improve the accuracy of the potential-based brain-computer interface, e.g., P300-based brain-computer interface. The brain-computer interface systems often use symbols or controlled objects as vision stimuli, but what visual stimuli can induce more obvious event-related potential is still unknown. This paper designed three kinds of visual stimuli, i.e., a square, an arrow, and a robot attached with an arrow, to analyze the influence of concreteness degree of the graph on the N200 and P300 potentials, and applied a support vector machine to compare the performance of the brain-computer interface under different stimuli. The results showed that, compared with the square, the robot attached with arrow and the arrow both induced larger N200 potential (P = 1.6 × 10−3, P = 4.2 × 10−2) and longer P300 potential (P = 2.2 × 10−3, P = 1.9 × 10−2) in the frontal area, but the amplitude under the arrow condition is smaller than the one under the robot attached with arrow condition. The robot attached with arrow increased the N200 potential amplitude of the square and arrow from 3.12 μV and 5.19 μV to 7.21 μV (P = 1.6 × 10−3, P = 8.9 × 10−2), and improved the accuracy rate from 59.95%, 61.67% to 74.45% (P = 2.1 × 10−2, P = 1.6 × 10−2), and the information transfer rate from 35.00 bits/min, 35.98 bits/min to 56.71 bits/min (P = 2.6 × 10−2, P = 1.6 × 10−2). This study shows that the concreteness of graphics could affect the N200 potential and the P300 potential. The abstract symbol could represent the meaning and evoke potentials, but the information contained in the concrete robot attached with an arrow is more correlated with the human experience, which is helpful to improve the amplitude. The results may provide new sight in modifying the stimulus interface of the brain-computer interface.
Abstract： Objective To investigate the change of tissue structure and epithelial barrier function of excluded esophagus after esophageal exclusion surgery for tracheoesophageal fistula (TEF). Methods Twentyeight hybrid dogs were divided into 3 groups with random number method. For group A (n=12), fistula was excluded; for group B (n=12), only the esophagus was excluded; and group C (n=4) was the control group. The normal and excluded esophagus of the three groups were observed through general sampling, HE staining, transmission electron microscope (TEM), scanning electron microscope (SEM) and Lanthanum trace labeling. The interstitial space dilation (ISD) of the cells on the esophageal mucosa was measured and the number of desmosome in the intercellular space was calculated. Results The changes of tissue structure and epithelial barrier function of the excluded esophagus were similar between group A and group B. Compared with group C, group A and B showed the following changes: esophageal structure changed, submucous glandular tissues reduced or disappeared; the interstitial space increased, the number of desmosome decreased, and the epithelial barrier function attenuated, but the basal lamina did not changed and lanthanum did not break through it. For the dogs in group C, esophageal mucosa could be observed, submucosa was complete and a large number of gland tissues and micrangiums could be seen in it. The number of desmosome for group A, B and C was 0.21±0.03 entries/μm2, 0.22±0.05 entries/μm2, and 0.32±0.03 entries/μm2 respectively, which showed a significant difference between group A, B and group C (Plt;0.05), while there was no significant difference between group A and group B (Plt;0.05). The average interstitial space for group A, B and C was 2.11±0.56 μm, 2.04±0.77 μm, and 1.84±0.49 μm respectively. There was no significant difference between group A and B, while there was significant difference between group A, B and group C. Conclusion The esophageal exclusion surgery for refractory TEF is safe, feasible, and effective with few complications, and deserved to be popularized.
ObjectiveTo compare the short-term effectiveness of femoral prosthesis with different neck-shaft angles for the reconstruction of proximal femoral anatomy after total hip arthroplasty (THA). MethodsBetween January 2012 and December 2013, 101 patients undergoing unilateral THA who accorded with selection criteria were selected for a retrospective study. The patients were divided into 2 groups:during THA, femoral prosthesis with 135° neck-shaft angle was used in 52 patients (group A) and femoral prosthesis with 127° neck-shaft angle was used in 49 patients (group B). There was no significant difference in gender, age, weight, body masss index, pathogeny, disease duration, preoperative neck-shaft angle, leg discrepancy, and preoperative Harris score between 2 groups (P>0.05). The postoperative Harris score was recorded to evaluate the effectiveness. And the femoral offset of the operated and contralateral sides, the change value of the femoral offset (xFO), the ratio of xFO to the offset of contralateral side (sdFO), the number of patients whose sdFO was more than 15% or less than -15% (outlier), the global offset, the height of femoral head rotation center, and leg discrepancy were measured at postoperation. ResultsOperative incision healed by first intension in 2 groups; no complication of infection, dislocation, or revision was found. All patients were followed up 12-32 months (mean, 23 months). The Harris score at last follow-up were significantly improved when compared with preoperative score in 2 groups (P＜0.05), but there was no signficant difference between 2 groups (t=1.267, P=0.832). The xFO and sdFO of group B were significantly larger than those of group A (P＜0.05); the number of outlier was 20 in group A and was 33 in group B, showing significant difference (P=0.005). The height of femoral head rotating center and global offset at 3 months after operation showed no signficant difference between 2 groups (P>0.05). And significant improvement in leg discrepancy was found at 3 months in 2 groups (P＜0.05), but there was no significant difference between 2 groups (t=0.403, P=0.689). ConclusionBoth of the two femoral prosthesis with different neck-shaft angles can restore the proximal femoral anatomy well and gain similar early effectiveness after THA. However, the Stryker Trident femoral prosthesis with 127° neck-shaft angle may have the tendency to enlarge the femoral offset.
As pigs are similar to humans in anatomy, physiology and pathology, nutrition metabolism and disease characteristics, genetically modified pigs are already used for the studies of disease mechanism, pathology and toxicology and the evaluation of drugs. But the production of large modified animals is difficult, cumbersome, time-consuming and costly. With the breakthrough of gene editing technology, clustered regularly interspersed short palindromic repeat (CRISPR)/CRISPR-associated 9( Cas9)(CRISPR/Cas9) technology has greatly improved the mutation efficiency, reduced the cost and simplified the steps, and promoted the widespread application of genetically modified pigs. In this paper, the production methods of genetically modified pigs and the research progress of genetically modified pigs by CRISPR/Cas9 in the medical field were reviewed.