The study of neuronal activity with low frequency has shown an increasing interest for its greater stability and reliability recent years. One challenge in analyzing this kind of activity is to find similarities and differences between signals efficiently and effectively. The traditional analysis methods, such as short-time Fourier transform, are easily obscured by background noises and often involve a large number of parameters. Therefore, this paper introduces a novel time-frequency analysis method based on wavelet transformation and half-ellipsoid modeling to extract instantaneous frequency and instantaneous phase information. This method overcomes some shortcomings of conventional time-frequency analysis. In this method, wavelet transformation is used to provide high-level representations of raw signals, and parsimonious half-ellipsoid models are used to extract changes in time domain and frequency domain of neural recordings. The method was validated to local field potentials (LFPs) of olfactory bulb of anesthetized rats during three different odor stimuli. The results suggested that this method could detect odor-relevant features from olfactory signals with large variability. The Odors then were classified with support vector machine (SVM) algorithm and the classification accuracy reached 79.4%.
ObjectiveTo evaluate the curative effect of laparoscopic assisted and open D2 radical resection in treatment of advanced gastric cancer. MethodsThe clinical data of 76 cases performed by laparoscopic assisted D2 radical resection (laparoscopic group) and 104 cases performed by open operation (open group) from October 2010 to October 2012 in our center were retrospective analized.Operation related index, postoperative recovery, and extent of radical resection of tumor of 2 groups were compared. ResultsThe operative time of the laparoscopic group[(192.5±14.8) min]was longer than that open group[(171.5±16.5) min, P < 0.05].But the blood loss, postoperative drainage, length of incision, and hospital stay of the laparoscopic group were significantly less or shorter than those of open group (P < 0.05).There were no significant difference in postoperative complications and extent of radical resection of tumor between the 2 groups (P > 0.05).There were no residual tumor in distal margin and operatiive death case in both 2 groups. ConclusionComparing with open operation, the laparoscopic assisted surgery for advanced gastric cancer could achieve the same clinical outcomes, and obvious advantage of minimal invasion.
ObjectiveTo analyze short-term outcomes of hand assisted laparoscopic (HAL) D2 radical distal gastrectomy for gastric cancer and summarize clinical experiences. MethodsThe clinical data of 199 patients with gastric cancer undergoing D2 radical distal gastrectomy from December 2010 to December 2013 in this hospital were analyzed. HAL (HAL group, n=92) and traditonal open (TO group, n=107) D2 radical distal gastrectomy were performed. The operation time, incision length, intraoperative blood loss, number of lymph nodes harvested, postoperative hospital stay, and postoperative complications were compared between these two groups. ResultsThere was no residue of cancer cells at the surgical margin in the HAL group and the TO group. Compared with the TO group, the average incision length was obviously shorter (P < 0.01) and the average intraoperative blood loss was obviously less (P < 0.05) in the HAL group. The average operation time, the average number of lymph nodes harvested, and the average postoperative hospital stay had no significant differences between the HAL group and the TO group (P > 0.05). One case was died of unknown gastrointestinal bleeding in the HAL group and the TO group, respectively. The postoperative complication rate was 9.78% (9/92) in the HAL group and 11.21% (12/107) in the TO group, there was no significant difference (P > 0.05). ConclusionsHAL D2 radical distal gastrectomy for gastric cancer don't increase operation time. It has some advantages of minimal invasion and safety as compared with traditional open surgery.