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Objectives. Endoscopic submucosal dissection (ESD) for early colorectal neoplasms is regarded as a difficult technique and should commence after receiving the experiences of ESD in the stomach. The implementation of colorectal ESD in countries where early gastric cancer is uncommon might therefore be difficult. The aim is to delineate the feasibility and the learning curve of colorectal ESD performed by a colonoscopist with limited experience of gastric ESD. Methods. The first fifty cases of colorectal ESD, which were performed by a single colonoscopist between July 2010 and April 2013, were enrolled. Results. The mean of age was 64 (±9.204) years with mean size of neoplasm at 33 (±12.63) mm. The mean of procedure time was 70.5 (±48.9) min. The rates of en bloc resection, R0 resection, and curative resection were 86%, 86%, and 82%, respectively. Three patients had immediate perforation, but no patient developed delayed perforation or delayed bleeding. Conclusion. Our result disclosed that it is feasible for colorectal ESD to be performed by a colonoscopist with little experience of gastric ESD through satisfactory training and adequate case selection.

In colonoscopy, the question of when and how to use carbon dioxide (CO(2)) insufflation remains uncertain. Inspection for the pathological changes during colonoscopy takes place during the withdrawal of the scope. This study aimed to determine whether CO(2) insufflation only at the withdrawal of the colonoscope has an effect comparable to that of CO(2) usage throughout the course of the procedure. Symptomatic patients were randomized in three groups: (1) patients given air insufflation (A; n = 33); (2) patients given CO(2) insufflation only at the time of scope withdrawal (CW; n = 33); and (3) patients given the CO(2) insufflation (C; n = 34) for the whole course of the colonoscopy. Patients were requested to answer questionnaires about their pain score during, at the end, and 1 h after the colonoscopy by using a pain numerical scale ranging from 0 to 10. The disparities of the pain score were noted at the end of the procedure and 1 h after the procedure (p = 0.026 and p < 0.001, respectively). We further analyzed the scores between two of the three groups. Both CW (vs. A; procedure end: p = 0.012, 1 h after: p = 0.001) and C (vs. A; procedure end: p = 0.072, 1 h after: p < 0.001) showed less postprocedure pain when compared with the group A. The pain score between CW and C were similar at each time segment (procedure end: p = 0.555, 1 h after: p = 0.491). CO(2) insufflation merely at the withdrawal of the colonoscope improved postprocedural abdominal discomfort and the effect was not inferior to that of full course CO(2) insufflation.

We propose a multi-wavelength fiber laser employing a double-pass Mach-Zehnder interferometer filter, a piece of polarization maintaining fiber, a semiconductor optical amplifier and an optical isolator. The proposed fiber laser has the advantages of stable multi-wavelength lasing with 33 channels in standard wavelength division multiplexing channel spacing of 0.4 nm using 15 m polarization maintaining fiber. Power ripple among channels could be reduced by increasing the bias current of the semiconductor optical amplifier.

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