Esophageal Nocturnal Baseline Impedance and Post-reflux Swallow-induced Peristaltic Wave Index in Identifying Proton Pump Inhibitor-refractory Non-erosive Reflux Disease

( Yan Wang ),( Bixing Ye ),( Meifeng Wang ),( Lin Lin ),( Liuqin Jiang ) 대한소화기기능성질환·운동학회 2021 Journal of Neurogastroenterology and Motility (JNM Vol.27 No.4

Background/Aims Esophageal mean nocturnal baseline impedance (MNBI) levels and post-reflux swallow-induced peristaltic wave (PSPW) index could increase the diagnostic value of 24-hour multichannel intraluminal impedance and pH monitoring in patients with gastroesophageal reflux disease. This study aims to compare the MNBI and PSPW index in patients with no evidence of erosive reflux disease. Methods Impedance-pH monitoring tracings from 70 patients, 50 with non-erosive reflux disease (NERD) and 20 with functional heartburn (FH), were reviewed. According to proton pump inhibitors (PPI) treatment response, NERD patients were divided into NERD/PPI responders and NERD/PPI nonresponders. MNBI, PSPW index, and intercellular spaces were measured and compared among each group. Results MNBI values and PSPW index were lower in NERD patients than in FH (P < 0.01 and P < 0.05, respectively). MNBI positively correlated with PSPW index (r = 0.525, P < 0.001). NERD/PPI responders had lower MNBI values and PSPW index compared to NERD/PPI nonresponders (both P < 0.01). MNBI and PSPW index distinguished NERD from FH patients with an area under the curve of 0.914 and 0.677, respectively. Wider intercellular space could be identified in patients with NERD (P < 0.01). Conclusion MNBI and PSPW index may differentiate NERD from FH patients and relate to PPI treatment efficacy in patients with NERD. (J Neurogastroenterol Motil 2021;27:525-532)

A Pilot Study of Clinical Evaluation and Formation Mechanism of Irritable Bowel Syndrome-like Symptoms in Inflammatory Bowel Disease Patients in Remission

( Haiyang Wang ),( Xiaojing Zhao ),( Xiufang Cui ),( Meifeng Wang ),( Chunhua Jiao ),( Jiajia Li ),( Yan Yang ),( Yi Li ),( Hongjie Zhang ) 대한소화기기능성질환·운동학회 2021 Journal of Neurogastroenterology and Motility (JNM Vol.27 No.4

Background/Aims Some inflammatory bowel disease (IBD) patients in remission suffer from irritable bowel syndrome (IBS)-like symptoms (IBD-IBS). The pathogenesis has not yet been elucidated. The study aim is to evaluate relationships among quality of life (QOL), psychological status, and visceral sensitivity, and explore the formation mechanism of IBD-IBS. Methods Forty-seven patients with Crohn’s disease in remission, 24 ulcerative colitis in remission, 26 IBS, and 20 healthy controls were included in the study. The abdominal pain, QOL, anxiety, and depression were evaluated through questionnaires. Visceral sensitivity was measured by rectal balloon distension. The serum levels of 5-hydroxytryptamine (5-HT) and nerve growth factor (NGF) were measured by enzyme-linked immunosorbent assay. The expressions of tryptase, 5-HT, NGF, and related receptors in colonic tissues were detected by immunohistochemistry and western blot. Results Prevalence of IBS-like symptoms in Crohn’s disease and ulcerative colitis patients in clinical remission was 29.8% and 50.0%, respectively. The QOL was lower, the anxiety/depression scores were higher in IBD-IBS patients than those without IBS-like symptoms. Additionally, patients with IBD-IBS existed visceral hypersensitivity. Besides, abdominal pain was associated with poor QOL, visceral hypersensitivity, anxiety, and depression in IBD-IBS patients. The number of mast cells (MCs) and expressions of 5-HT, NGF, and related receptors were higher in IBD-IBS patients than those with no such symptoms. The serum levels of 5-HT and NGF positively correlated with abdominal pain and visceral hypersensitivity. Conclusion IBD-IBS patients may have low QOL and psychological abnormalities, as wells as visceral hypersensitivity which may be related to increased 5-HT and NGF levels released from activated mast cells. (J Neurogastroenterol Motil 2021;27:612-625)

Preparation and Microstructure Control of PMDA/ODA Polyimide Hollow Fibers

Meifeng Xiao,Jianhua Li,Huanyu Lei,Mengying Zhang,Hongqing Niu,Dezhen Wu,Xiaodong Wang 한국섬유공학회 2020 Fibers and polymers Vol.21 No.5

Poly(4,4'-oxydiphenylene pyromellitimide) (PMDA/ODA) hollow fiber membranes with regular morphologieshave been successfully prepared through a two-step dry-jet wet spinning method. The morphologies of polyimide (PI) hollowfibers were regulated via adjusting the major spinning parameters, including dope/bore flow rate ratio, bore fluidcomposition, coagulation bath temperature and air gap distance. SEM results show that the morphologies of PI hollow fibersstrongly depended on the spinning conditions, and fibers with regular asymmetric structures were finally obtained. The fiberwall thickened with the increase of dope/bore flow rate ratio, and the fibers could well self-support when the dope/bore flowrate ratio ranged from 3:1 to 4:1. While higher DMAc content in the bore fluid was conducive to the formation of finger-likevoids, reduced amount of DMAc would result in smaller finger-like voids and thereby lower overall porosities as well asbetter mechanical properties. Moreover, the finger-like voids and surface defects could be effectively prevented by loweringthe coagulation bath temperature or extending the air gap distance. Gas separation and mechanical properties of the hollowfibers were found closely related to these morphological changes. On such basis, regular PI hollow fibers with differentmicrostructures and Young’s modulus up to 1040 MPa were successfully fabricated. The prepared polyimide hollow fibersare promising candidates for fine separation under high temperature and high pressure or can be employed as the support ofcomposite membranes.

Theoretical investigation of deformation characteristics of stratified rocks considering geometric and mechanical variability

Peitao Wang,Meifeng Cai,Fenhua Ren,Changhong Li,Tianhong Yang 한국지질과학협의회 2017 Geosciences Journal Vol.21 No.2

Anisotropy is one of the most distinct features of stratified rock mass and it must be considered in engineering design and stability analysis. On the basis of linear elastic theory and displacements equivalence, a computational model considering elastic anisotropy was established. The equivalent elastic modulus and equivalent Poisson’s ratio of the stratified rock perpendicular and parallel to the loading direction were discussed. The relations of material properties and geometry parameters with the equivalent elastic modulus and equivalent Poisson’s ratio in two directions were studied. Uniaxial compressive test was conducted and the elastic modulus and Poisson’s ratio in the proposed model agreed well with experimental results. The comparison between a comprehensive set of experimental data and theoretical analysis data proves that the proposed constitutive model can effectively characteristic the mechanical behavior of stratified rocks. The proposed model can consider the effects of material parameters and geometry parameters of rock and joints on the mechanical behavior of stratified rock mass. Moreover, the elastic anisotropy was considered in the model. Thus, the model can supply some valuable reference in studying deformation of stratified rock mass and engineering design.

Numerical analysis on scale effect of elasticity, strength and failure patterns of jointed rock masses

Peitao Wang,Tianhong Yang,Tao Xu,Meifeng Cai,Changhong Li 한국지질과학협의회 2016 Geosciences Journal Vol.20 No.4

It is of great importance to study the failure process and scale effect of jointed rock mass in the field of rock mechanics and mining engineering. In the present paper, initially the uniaxial compression test on granite was performed and acoustic emission (AE) sequence was acquired during the compression process in laboratory. Results from numerical simulations using the particle flow code in two dimensions (PFC2D) were presented, and compared with experimental measurements. It was observed that the approach was reasonably good in predicting the real response of granite rock samples. The mechanical parameter of joint model was then calibrated based on PFC2D model with experimental results. Finally the mechanical properties of complex rocks with discrete fracture network (DFN) were studied and scale effects on the elasticity and strength were then investigated. The result showed that the failure pattern was similar when the ratio of joint contact bond strength (both shear and normal) to rock contact bond strength was in the range of 3~9%. The elastic modulus and strength parameters were changed with the sizes of rock sample for DFN models. Moreover, the variation of rock failure pattern under different sizes was also studied and finally the representative elementary volume (REV) size of the considered rock mass was estimated to be 9 × 9 m. It is suggested that the failure pattern analysis should be considered in the REV study of jointed rock mass.

Factors of Reflux Episodes With Post-reflux Swallow-induced Peristaltic Wave in Gastroesophageal Reflux Disease

( Hairong Xu ),( Bixing Ye ),( Yu Ding ),( Meifeng Wang ),( Lin Lin ),( Liuqin Jiang ) 대한소화기기능성질환·운동학회(구 대한소화관운동학회) 2020 Journal of Neurogastroenterology and Motility (JNM Vol.26 No.3

Background/Aims It is known that post-reflux swallow-induced peristaltic wave (PSPW) index represents the chemical clearance of the esophagus. However, few studies have explored why some reflux episodes could induce PSPW while others in the same patient could not. The purpose of this study is to investigate the characteristics of reflux episodes which could elicit PSPW. Methods In this study, 269 reflux episodes were detected, of which 90 with a PSPW and 179 without a PSPW. Comparisons were made between the characteristics of reflux episodes with a PSPW and without a PSPW. The characteristics were including nadir pH, pH drop, proximal extent (cm, sec), ascending velocity (cm/sec), volume clearance time, acid clearance time, percentage acidic (%), 15 to 60-minute acid burden (seconds), and 15- to 60-minute volume burden (seconds). The characteristics between the 2 groups were compared through performing Wilcoxon signed rank test. Results Reflux episodes followed by a PSPW were significantly associated with a higher proximal extent than those without a PSPW. After the reflux episodes, higher volume clearance time and larger volume burden were more likely to trigger a PSPW. However, there were no significant differences between the 2 groups in nadir pH, pH drop, ascending velocity, acid clearance time, percentage acidic, or acid burden. Conclusions The role of acid seems to be less important in a reflux episode inducing a PSPW. Proximal reflux episodes are more likely to induce a PSPW. The depression of volume clearance may also be an important factor in eliciting a PSPW. (J Neurogastroenterol Motil 2020;26:378-383)

Esophageal Body Motility for Clinical Assessment in Patients with Refractory Gastroesophageal Reflux Symptoms

( Liuqin Jiang ),( Bixing Ye ),( Ying Wang ),( Meifeng Wang ),( Lin Lin ) 대한소화기기능성질환·운동학회(구 대한소화관운동학회) 2017 Journal of Neurogastroenterology and Motility (JNM Vol.23 No.1

Background/Aims Little data exists about esophageal body dysmotility and reflux patterns in refractory gastroesophageal reflux disease (RGERD) patients off therapy. We aimed to evaluate effects of esophageal body dysmotility on reflux parameters in RGERD patients by combining impedance-pH monitoring and high-resolution manometry (HRM). Methods We retrospectively reviewed the impedance-pH data and HRM metrics in patients with refractory gastroesophageal reflux symptoms. Impedance-pH monitoring and manometric data were compared between 2 groups: ineffective esophageal motility (IEM) and normal motility. Results Forty-eight patients (30 males, mean age 54.5 years) were included (16 erosive esophagitis, 24 non-erosive reflux disease, and 8 functional heartburn), amongst which 24 subjects showed IEM, and others had normal motility. Number of patients who had a large break in the IEM group was significantly higher than that of normal motility patients. IEM group had more patients with weakly acid reflux and long term acid reflux than the normal group (P = 0.008, P = 0.004, respectively). There was no statistical difference in baseine impedance levels from z4 to z6 between the 2 groups (2911 ± 1160 Ω vs 3604 ± 1232 Ω, 2766 ± 1254 Ω vs 3752 ± 1439 Ω, 2349 ± 1131 Ω vs 3038 ± 1254 Ω, all P > 0.05). Acid exposure time, numbers of long term acid reflux and weakly acid reflux showed strong negative correlation with esophageal body motility and/or lower esophageal sphincter function. Conclusions IEM was associated more with acid exposure, abnormal weakly acid reflux, and long term acid reflux in RGERD patients. These data suggested the role of esophageal body dysmotility in the pathophysiological mechanisms of RGERD patients. (J Neurogastroenterol Motil 2017;23:64-71)