ABSTRACT
Objective:To evaluate the effects of individual extralevator abdominoperineal excision (ELAPE) of rectal neoplasms in the low posterior wall on the pelvic floor by finite element analysis. Methods:MIMICS 10.01, Geo Magic Studio 12, and ANSYS Workbench 14.0 were used to analyze the magnetic resonance data obtained from the pelvic region of 27 healthy nulliparous volunteers. Three types of finite element models (intact model, ELAPE model, and individual ELAPE model) were developed. The maximal stress on non levator ani tissues were analyzed using the three models, while the maximal stress on levator ani tissues were analyzed using the in-tact model and the individual ELAPE model. Their stress distributions under the same pressure were analyzed and compared. Results:The maximal stress on non levator ani tissues obtained using the intact model, ELAPE model, and individual ELAPE model were (1.963± 0.061), (5.127 ± 0.070), and (3.667 ± 0.126) MPa, respectively, with P<0.01. High-stress zones were obtained at the joints with pelvic walls on both sides using the three models, while the maximal stresses were obtained at the joints with pubis on both sides. The maxi-mal stress on levator ani tissues obtained using the intact model and individual ELAPE model were (0.812 ± 0.042) MPa and (1.437 ± 0.043) MPa, respectively. Thus, the individual ELAPE model yielded higher values of maximal stress compared to the intact model. Both models generated high-stress zones at the joints with tendinous arch of levator ani tissues on both sides, and maximum stresses at the joints with pubis on both sides. Conclusion:Individual ELAPE decreases the stress on non levator ani tissues. This suggests that the risk of postoperative pelvic floor hernia is relatively reduced.
ABSTRACT
Objective To evaluate the effects of individual extralevator abdominalperineal excision (ELAPE) for rectal neoplasms below levator hiatus on pelvic floor by finite element analysis. Methods MIMICS 10.01, GeoMagic Studio 12 and ANSYS Workbench 14.0 were used to deal with magnetic resonance data of 27 healthy nulliparous volunteers'pelvic, and then three types of finite element models were developed:intact models, ELAPE models and individual ELAPE models. The maximum stress in non levator ani tissue under the same load were measured in three types of models, and levator ani 's maximal stresses were measured in intact model and individual ELAPE and their stress distributions under the same pressure were analyzed and compared. Results The maximal stresses of non-levator ani tissue were (1.963±0.061) MPa, (5.127±0.070) MPa and (4.703±0.110) MPa for intact model, ELAPE model and individual ELAPE model respectively. The maximal stress was lower in individual ELAPE model than that in ELAPE model, but which was higher than that of intact model (P<0.01). The high-stress zone was found at the joints with surrounding structures on both sides of intact model and ELAPE model. The high-stress zone was found in front of the joints with surrounding structures on both sides in individual ELAPE model. The maximal stresses of three types of models were found in front of both sides. In intact model levator ani 's maximal stress was (0.812 ± 0.042) MPa, which was higher than that of individual ELAPE model (0.719 ± 0.027) MPa (P<0.01). The high-stress zone of intact model was found in front of the joints on both sides. The maximal stress was showed at ventral ends on both sides. For the individual ELAPE model the high-stress zone was found at the anterior part of the levator ani muscle and the surrounding structure. The maximum stress appeared at the top end of the left and right sides. Conclusion This individual ELAPE is able to decrease the stress of non-levator ani tissue, which suggests that the risk of postoperative pelvic floor hernia is relatively reduced.
ABSTRACT
Microbial fuel cells (MFCs) is a highly promising bioelectrochemical technology and uses microorganisms as catalyst to convert chemical energy directly to electrical energy. Microorganisms in the anodic chamber of MFC oxidize the substrate and generate electrons. The electrons are absorbed by the anode and transported through an external circuit to the cathode for corresponding reduction. The flow of electrons is measured as current. This current is a linear measure of the activity of microorganisms. If a toxic event occurs, microbial activity will change, most likely decrease. Hence, fewer electrons are transported and current decreases as well. In this way, a microbial fuel cell-based biosensor provides a direct measure to detect toxicity for samples. This paper introduces the detection of antibiotics, heavy metals, organic pollutants and acid in MFCs. The existing problems and future application of MFCs are also analyzed.
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Objective To evaluate the effects of unilateral extralevator abdominal-perineal excision (ELAPE) surgery and the ELAPE surgery on the pelvic floor detected by finite element analysis. Methods Three kinds of finite element mod?el were developed:the intact model, ELAPE model and the unilateral ELAPE model. The maximal stress and stress distribu?tions of each model under the same pressure were analyzed and compared. Results In the unilateral ELAPE model, non-le?vator ani tissue’s maximal stress on the levator ani reserved side was lower than that in ELAPE model, and was similar to that in the intact model. Its maximal stress on the excised side was lower than that in ELAPE model, and which was higher than that of intact model. Its maximal stress on the reserved side was lower than that of on the excised side. Conclusion Compared to the ELAPE surgery, the unilateral ELAPE surgery is able to reduce the stress of non-levator ani tissue on both sides, especially on the levator ani reserved side.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the demonstration ability of 64-multislice spiral computed tomography angiography (MSCTA) with 3-D reconstruction image fusion for the anatomy of perigastric artery.</p><p><b>METHODS</b>From November 2012 to December 2013 in the Nanfang Hospital, a total of 469 patients underwent abdominal 64-MSCTA. 3-D reconstruction technique computed tomography angiography (CTA) was used to reconstruct perigastric arteries. The origin and the course of perigastric arteries were observed. Branching pattern of the hepatic artery was classified by Michels standard, and branching pattern of the right gastric artery was classified into three types according to RGA ramification patterns.</p><p><b>RESULTS</b>Five patients failed to demonstrate hepatic artery because of abnormal development. 3-D reconstruction clearly showed the perigastric arteries in other 464 patients (98.9%). The most common branching pattern of hepatic artery was Michels type I in 346 patients (74.6%). Hepatic artery variation was found in 118 patients (25.4%), including 9 patients of non-Micles type (7.6%). 3-D reconstruction clearly showed the branching pattern of the right gastric artery in 337 patients (72.6%), including 54(16.0%) of proximal pattern, 221 of distal pattern(65.6%), 56 of caudal pattern (16.6%), and 6 of other pattern (3 from splenic artery, 3 from superior mesenteric artery).</p><p><b>CONCLUSION</b>64-MSCTA with 3-D reconstruction can clearly reveal individual perigastric arteries, and can provide guidance for laparoscopic gastrectomy.</p>