The Clinical Value of Ultrasound Image Texture Analysis in the Diagnosis of Uterine Adhesions

Purpose: This review examines the diagnostic value of transvaginal 3D ultrasound image texture analysis for the diagnosis of uterine adhesions. Materials and Methods: The total clinical data of 53 patients with uterine adhesions diagnosed by hysteroscopy and the imaging data of transvaginal three-dimensional ultrasound from the Second Affiliated Hospital of Chongqing Medical University from June 2022 to August 2023 were retrospectively analysed. Based on hysteroscopic surgical records, patients were divided into two independent groups: normal endometrium and uterine adhesion sites. The samples were divided into a training set and a test set, and the transvaginal 3D ultrasound was used to outline the region of interest (ROI) and extract texture features for normal endometrium and uterine adhesions based on hysteroscopic surgical recordings, the training set data were feature screened and modelled using lasso regression and cross-validation, and the diagnostic efficacy of the model was assessed by applying the subjects’ operating characteristic (ROC) curves. Results: For each group, 290 texture feature parameters were extracted and three higher values were screened out, and the area under the curve of the constructed ultrasonographic scoring model was 0.658 and 0.720 in the training and test sets, respectively. Conclusion Relative clinical value of transvaginal three-dimensional ultrasound image texture analysis for the diagnosis of uterine adhesions.

RGS4 promotes the progression of gastric cancer through the focal adhesion kinase/phosphatidyl-inositol-3-kinase/protein kinase B pathway and epithelial-mesenchymal transition

BACKGROUND Regulator of G protein signaling(RGS)proteins participate in tumor formation and metastasis by acting on theα-subunit of heterotrimeric G proteins.The speci-fic effect of RGS,particularly RGS4,on the progression of gastric cancer(GC)is not yet clear.AIM To explore the role and underlying mechanisms of action of RGS4 in GC develop-ment.METHODS The prognostic significance of RGS4 in GC was analyzed using bioinformatics based public databases and verified by immunohistochemistry and quantitative polymerase chain reaction in 90 patients with GC.Function assays were employed to assess the carcinogenic impact of RGS4,and the mechanism of its possible influence was detected by western blot analysis.A nude mouse xenograft model was established to study the effects of RGS4 on GC growth in vitro.RESULTS RGS4 was highly expressed in GC tissues compared with matched adjacent normal tissues.Elevated RGS4 expression was correlated with increased tumor-node-metastasis stage,increased tumor grade as well as poorer overall survival in patients with GC.Cell experiments demonstrated that RGS4 knockdown suppressed GC cell proliferation,migration and invasion.Similarly,xenograft experiments confirmed that RGS4 silencing significantly inhibited tumor growth.Moreover,RGS4 knockdown resulted in reduced phosphorylation levels of focal adhesion kinase,phosphatidyl-inositol-3-kinase,and protein kinase B,decreased vimentin and N-cadherin,and elevated E-cadherin.CONCLUSION High RGS4 expression in GC indicates a worse prognosis and RGS4 is a prognostic marker.RGS4 influences tumor progression via the focal adhesion kinase/phosphatidyl-inositol-3-kinase/protein kinase B pathway and epithelial-mesenchymal transition.

The effect of typical seawater cations on the adhesion of mussel protein Mefp-1 based on dissipative quartz crystal microbalance

Mussels are common anchoring organisms that adhere to the surfaces of various substrates with their byssus.The adhesion of mussel to substrates is contingent upon the presence of mussel foot proteins,of which Mytilus edulis foot protein-1(Mefp-1)has been identified as the most abundant protein.It has been found that lipids are involved in the mussel adhesion process and can facilitate Mefp-1adhesion.In this research,the adhesion behavior of Mefp-1 on various substrate surfaces under the effect of typical seawater cations with or without the presence of lipid were investigated using a quartz crystal microbalance with dissipation(QCM-D).Results indicate that the presence of cations Ca^(2+),Mg^(2+),Na^(+),and K^(+)leads to varying degrees of reduction in the adhesion performance of Mefp-1 on different substrates.The degree of this reduction,however,was much alleviated in the presence of palmitic acid,which is involved in the mussel adhesion process.Therefore,the involvement of palmitic acid is advantageous for mussel protein adhesion to the substrate surface in the marine environment.This study illustrated the significant contribution of palmitic acid to mussel adhesion,which can help to better understand biofouling mechanisms and develop biomimetic adhesive materials.

Adhesive small bowel adhesions obstruction: Evolutions in diagnosis, management and prevention

Intra-abdominal adhesions following abdominal surgery represent a major unsolved problem. They are the first cause of small bowel obstruction. Diagnosis is based on clinical evaluation, water-soluble contrast followthrough and computed tomography scan. For patients presenting no signs of strangulation, peritonitis or severe intestinal impairment there is good evidence to support non-operative management. Open surgery is the preferred method for the surgical treatment of adhesive small bowel obstruction, in case of suspected strangulation or after failed conservative management, but laparoscopy is gaining widespread acceptance especially in selected group of patients. "Good" surgical technique and anti-adhesive barriers are the main current concepts of adhesion prevention. We discuss current knowledge in modern diagnosis and evolving strategies for management and prevention that are leading to stratified care for patients.

Peritoneal adhesions after laparoscopic gastrointestinal surgery

Although laparoscopy has the potential to reduce peritoneal trauma and post-operative peritoneal adhesion formation, only one randomized controlled trial and a few comparative retrospective clinical studies have addressed this issue. Laparoscopy reduces de novo adhesion formation but has no efficacy in reducing adhesion reformation after adhesiolysis. Moreover, several studies have suggested that the reduction of de novo post-operative adhesions does not seem to have a significant clinical impact. Experimental data in animal models have suggested that CO2 pneumoperitoneum can cause acute peritoneal inflammation during laparoscopy depending on the insufflation pressure and the surgery duration. Broad peritoneal cavity protection by the insufflation of a low-temperature humidified gas mixture of CO2, N2O and O2 seems to represent the best approach for reducing peritoneal inflammation due to pneumoperitoneum. However, these experimental data have not had a significant impact on the modification of laparoscopic instrumentation. In contrast, surgeons should train themselves to perform laparoscopy quickly, and they should complete their learning curves before testing chemical anti-adhesive agents and anti-adhesion barriers. Chemical anti-adhesive agents have the potential to exert broad peritoneal cavity protection against adhesion formation, but when these agents are used alone, the concentrations needed to prevent adhesions are too high and could cause major post-operative side effects. Anti-adhesion barriers have been used mainly in open surgery, but some clinical data from laparoscopic surgeries are already available. Sprays, gels, and fluid barriers are easier to apply in laparoscopic surgery than solid barriers. Results have been encouraging with solid barriers, spray barriers, and gel barriers, but they have been ambiguous with fluid barriers. Moreover, when barriers have been used alone, the maximum protection against adhesion formation has been no greater than 60%. A recent small, randomized clinical trial suggested that the combination of broad peritoneal cavity protection with local application of a barrier could be almost 100% effective in preventing post-operative adhesion formation. Future studies should confirm the efficacy of this global strategy in preventing adhesion formation after laparoscopy by focusing on clinical end points, such as reduced incidences of bowel obstruction and abdominal pain and increased fertility.

Intrauterine transplantation of autologous bone marrow derived mesenchymal stem cells followed by conception in a patient of severe intrauterine adhesions

On a woman with severe intrauterine adhesions, hysteroscopy followed by cyclical hormone replacement therapy was tried for 5 months, for development of the endometrium. When this failed, autologous stem cells were tried as an alternative therapy. Adult autologous bone marrow mesenchymal stem cells isolated from patient’s own bone marrow and were cultured and placed in the endometrial cavity under ultrasound guidance after curettage. Patient was then given cyclical hormonal therapy. Endometrium was assessed intermittently using ultrasound. Three months later, endometrium partly recovered with improved ultrasonic echo. This resulted in spontaneous pregnancy followed by confirmation of gestational sac, yolk sac, and primitive heart tube pulse on ultrasound. Autologous bone marrow derived mesenchymal stem cells could regenerate injured endometrium not responding to conventional treatment and can be used as an alternative in females with severe Asherman’s syndrome.

Intrauterine Adhesions (IUAs) or Asherman’s Syndrome (AS) and the Stem Cells Treatment: A Systemic Review and Meta-Analysis

Background: Intrauterine Adhesions (IUAs) or Asherman’s Syndrome (AS) usually contains symptoms such as decreased menstrual flow or even amenorrhea, chronic pelvic pain, recurrent abortion and infertility. The current treatment of IUAs includes hysteroscopic adhesiolysis, oral hormone and biological barriers, but each of them has limitation. Stem cell therapy may be an expanding field seeking for therapy in IUAs. Objective: We will discuss current advances in stem cell therapy as a treatment for endometrial pathophysiology. Materials and Methods: We search on PubMed, Embase and Cochrane library and select several keywords on researches, then review the cell biology theories and animal experiments, finally do meta-analysis in human clinical trials. Results: 77 articles on PubMed, 71 articles on Embase and 17 articles on Cochrane Library, as a result, 37 articles are included under the criteria, which are intrauterine adhesions (IUAs), Asherman’s Syndrome (AS), cell therapy, stem cells, bone marrow stem cells, clinical trials, recent 10 years and human or animal experiments. The included criteria: original articles, cohort study, case control study, animal experiments, human clinical trials, high quality, 10 years recent. The excluded articles are case reports, meeting reports, low quality or more than 10 years ago. Conclusion: Stem cell may be a new therapeutic schedule for IUAs in the future clinical treatment, but it is necessary to compare it with traditional therapy such as oral hormone, also the development of random clinical tests should proceed. For clinical treatment on IUAs, stem cells could be a new choice.

Chinese medicine compound Changtong oral liquid on postoperative intestinal adhesions

AIM: The aim of this study was to observe the effect of a Chinese medicine compound Changtong oral liquid (CT) on tissue plasminogen activity (t-PA), plasminogen activator inhibitor (PAI), TGF-β1 and hydroxyproline (OHP). METHODS: Two sets of animal experiments were performed in the present study. Forty New Zealand rabbits and 48 Sprague-Dawley (SD) rats were assigned randomly to one of the five groups: sham adhesion, adhesion with saline, adhesion with low dosage of the CT, adhesion with middle dosage of the CT and adhesion with high dosage of the CT. t-PA and PAI activity in plasma, OHP and TGF-β1 expression in adhesion were investigated. Analysis of variance was used to test differences among groups. RESULTS: CT treatment increased plasma t-PA activity in rabbits but decreased TGF-β1 activity in rats. The data were expressed from low to high dose respectively as follows: t-PA, 46.1±8.6 μkat/L, 59.6±10.1 μkat/L, 64.0±11.5 μkat/L; TGF-β1 28±7.23%, 31±3.05%, 30±4.04%. There were significant differences compared with saline-treated animals (t-PA 26.4±5.1 μkat/L, TGF-β1 54±5.51%). OHP content in cecum of rabbits from middle and high but not low dose of CT lowered significantly as compared with saline-treated rabbits, 0.3641±0.1373, 0.3348±0.0321, 0.2757±0.0497 mg/g vs 0.4183±0.0883 mg/g of protein, P>0.05, P<0.05, P<0.05 respectively. The rabbit plasma PAI activity and OHP content in abdominal wall had no difference in all groups. CONCLUSION: CT treatment significantly enhanced t-PA activity in rabbits, but decreased TGF-β1 content in rats, OHP content in cecum of rabbits, and failed to affect the activity of PAI and OHP content in abdominal wall in rabbits, compared with saline group. The result suggests that CT could effectively prevent adhesions without interfering wound healina.

Nanoengineered Shear-Thinning Hydrogel Barrier for Preventing Postoperative Abdominal Adhesions

More than 90%of surgical patients develop postoper-ative adhesions,and the incidence of hospital re-admissions can be as high as 20%.Current adhesion barriers present limited efficacy due to difficulties in application and incompatibility with minimally invasive interventions.To solve thisclinical limitation,we developed an injectable and sprayable shear-thinning hydrogel barrier(STHB)composed of silicate nanoplatelets and poly(ethylene oxide).We optimized this technology to recover mechanical integrity after stress,enabling its delivery though inject-able and sprayable methods.We also demonstrated limited cell adhesion and cytotoxicity to STHB compositions in vitro.The STHB was then tested in a rodent model of peritoneal injury to determine its e cacy preventing the formation of postoperative adhesions.After two weeks,the peritoneal adhesion index was used as a scoring method to determine the formation of postoperative adhesions,and STHB formulations presented superior e cacy compared to a commercially available adhesion barrier.Histological and immunohistochemical examination showed reduced adhesion formation and minimal immune infiltration in STHB formulations.Our technology demonstrated increased e cacy,ease of use in complex anatomies,and compatibility with di erent delivery methods,providing a robust universal platform to prevent postoperative adhesions in a wide range of surgical interventions.

Prevention of peritoneal adhesions:A promising role for gene therapy

Adhesions are the most frequent complication of abdominopelvic surgery,yet the extent of the problem,and its serious consequences,has not been adequately recognized.Adhesions evolved as a life-saving mecha-nism to limit the spread of intraperitoneal inflammatory conditions.Three different pathophysiological mechanisms can independently trigger adhesion formation.Mesothelial cell injury and loss during operations,tissue hypoxia and inflammation each promotes adhesion formation separately,and potentiate the effect of each other.Studies have repeatedly demonstrated that interruption of a single pathway does not completely prevent adhesion formation.This review summarizes the pathogenesis of adhesion formation and the results of single gene therapy interventions.It explores the prom-ising role of combinatorial gene therapy and vector modif ications for the prevention of adhesion formation in order to stimulate new ideas and encourage rapid advancements in this field.

Abdominal and pelvic adhesions: Possible role of leiomyomas and skin scar anomaly in profiling high risk patients

Background and aims: Adhesions can cause important morbidity including abdominal and pelvic pain, intestinal obstructions, and infertility. When adhesions are formed, there is no efficient method, nowadays, to resolve them, thus the reduction of their prevalence relies on the prevention. Profiling high risk patients for abdominal and pelvic adhesions (APA) is an important step to this prevention. The risk factors of adhesions in our institution, the association between APA, leiomyomas and skin scar anomaly (SSA) were investigated. Methods: A cross-sectional study was conducted from March 1st to June 30th 2013 including patients who underwent laparotomy or laparoscopy. Patients’ characteristics, presence of a SSA and leiomyomas, as related to adhesions, were analyzed. Student’s t, Pearson’s Khi-square, Fisher’s Exact, Mann-Whitney tests and logistic regression were used. P values < 0.05 were considered statistically significant. Results: The frequency of adhesions was 41.74%. Patients had a mean age of 32.69 ± 8.94 years. Those with a previous abdominal surgery (PAS), SSA and leiomyomas had respectively 12 times [OR: 11.98, CI95 (4.63 - 30.97)], 3 times [OR: 2.79, CI95 (1.16 - 6.71) and 2.5 times [(OR: 2.49, CI95 (1.07 - 5.78)] more adhesions. In logistic regression, a PAS and leiomyomas remained associated significantly to adhesions with p = 0.000 and p = 0.037 respectively. Conclusion: In peritoneal adhesions, leiomyomas and SSA are other factors that may allow a cautious selection of high risk patients who must benefit from particular attention during surgery. Further well designed studies are necessary to investigate the accurate clinical relation among those three conditions.

Diagnostic Accuracy of Hysterosalpingography in the Identification of Intrauterine Adhesions in Infertile Women in a Referral Centre, Southern Nigeria

Background: Examination of the endometrial cavity is crucial in the management of infertile women. This evaluation is done by Hysterosalpingography (HSG) in the University of Port Harcourt Teaching Hospital. The diagnostic value and accuracy of hysterosalpingography varies in various centres and has not been assessed in the University of Port Harcourt Teaching Hospital (UPTH), hence this study. Methodology: A prospective cross sectional study done among 101 infertile women at the gynaecology clinic of the UPTH from December 2018 to July 2019. Socio-demographic data of women who met the eligibility criteria were collected. Their hysterosalpingographic and outpatient hysteroscopic findings were statistically analyzed using IBM SPSS for windows version 20.0. The validity and reliability statistics of hysterosalpingography for the identification of endometrial adhesions were determined and significance was reported at p-value < 0.05. The analyzed data was presented in tables and figure. Result: The respondents were all married, 66.3% of them were nulliparous, while 54.5% were above 35 years of age. Most, 93.1% of the studied group had at least secondary education and had duration of infertility of more than 2 years. There was a moderate strength of agreement in the diagnostic accuracy of HSG with hysteroscopy in the diagnosis of intrauterine adhesions;showing sensitivity and specificity of 59.6% and 90.9% respectively. The accuracy of HSG in the identification of intrauterine adhesions in this study was 73.3%. The agreement in the diagnostic accuracy of HSG using Hysteroscopy as a gold standard for intrauterine adhesions was therefore moderately significant (k = 0.482). Conclusion: HSG had an overall fair strength of agreement with office hysteroscopy in the identification of intrauterine adhesions. It is a specific but not a sensitive predictor of intrauterine adhesion.

Perihepatic adhesions: An unusual complication of hemolysis, elevated liver enzymes and low platelet syndrome

We present a case of symptomatic perihepatic adhesions,which developed after a pregnancy complicated by hemolysis,elevated liver enzymes and low platelet(HELLP)syndrome,in which a subcapsular liver hematoma occurred.Our patient presented with complaints of persistent,severe right-sided upper abdominal pain.The complaints developed gradually,one year after a pregnancy that had been complicated by HELLP syndrome with a subcapsular liver hematoma.The hematoma had resolved spontaneously.An upperabdominal magnetic resonance imaging revealed a density between liver and diaphragm at the site of the former subcapsular hematoma,suspect of perihepatic adhesions.The presence of perihepatic adhesions was confirmed during a laparoscopy and treated by adhesiolysis in the same session.The adhesions may have developed in response to the degradation process of the subcapsular liver hematoma during conservative treatment.This case of perihepatic adhesions may therefor be the first presentation of a long term sequel of subcapsular liver hematoma in HELLP syndrome.

Effect of enamel-grinding on adhesionstrength of enamel-resin junction

In this paper,we have tested the normal and mottled enamel in order to get some instructive information for the clinical treatment. As demonstrated by the results of our experiments, the grinding treatment of the enamel superficial layer has no significant improvement on the adhesional strength of the junction between the normally developed teeth and the resin. However, it does exhibit evident effect on the adhesional strength of the junction between the fluorosis teeth and the repairing resin.

Correlation of FoxF2 expression with MMPs, ADAMs and TGF-β1 pathway in intrauterine adhesions

Objective: To study the correlation of forkhead box F2 (FoxF2) expression with matrix metalloproteinases (MMPs), a disintegrin and metalloproteases (ADAMs), transforming growth factor-β1 (TGF-β1) pathway in intrauterine adhesions. Methods: The patients who underwent hysteroscopic surgery and were diagnosed with intrauterine adhesions according to postoperative pathology results in our hospital between March 2015 and January 2018 were selected as the IUA group, and the patients who underwent surgical resection and were diagnosed with uterine fibroid according to postoperative pathology results in our hospital during the same period were selected as the control group. The intrauterine adhesion tissues of the IUA group and the normal endometrial tissues of the control group were collected to measure the expression levels of FoxF2, MMPs and ADAMs-related molecules as well as TGF-β1 pathway molecules. Results: FoxF2, ADAM15, ADAM17, TIMP1, TGF-β1, Smad2, Smad3 and CTGF mRNA expression in the intrauterine adhesion tissues of IUA group were significantly higher than those of control group whereas MMP9 mRNA expression was significantly lower than that of control group;FoxF2 mRNA expression in the intrauterine adhesion tissues of IUA group was negatively correlated with MMP9 mRNA expression, and positively correlated with ADAM15, ADAM17, TIMP1, TGF-β1, Smad2, Smad3 and CTGF mRNA expression. Conclusion: The high expression of FoxF2 in intrauterine adhesions can inhibit protease activity and enhance TGF-β1 pathway function.

Overview of the Synthesis, Characterization, and Application of Tannin-Glyoxal Adhesive for Wood-Based Composites

More than a century after its initial synthesis,urea-formaldehyde(UF)resins still have dominant applications as adhesives,paints,and coatings.However,formaldehyde in this industry produces formaldehyde emissions that are dangerous to health.Scientists have spent the last decade replacing formaldehyde and phenol with environmentally friendly substances such as glyoxal and tannin to create bio-based adhesives.This review covers recent advances in synthesizing glyoxal tannin-based resins,especially those made from sustainable raw material substitutes and changes made to synthetic processes to improve mechanical properties.The efficacy of using tannin-glyoxal adhesives in producing wood-based composites has been proven.The glyoxylate reaction forms cross-linked bridges between the aromatic sites of the tannin and glyoxal molecular structures.Glyoxal tannin adhesive with a greater percentage of glyoxal than tannin will produce an adhesive with better characteristics.The gel time reduces as the hardener concentration rises from 7.5%to 15%when glyoxal is used in adhesives.However,excessive amounts of glyoxal will result in a decrease in viscosity values.Glyoxal exhibits faster delivery degradation when it reaches a maximum temperature of approximately 130°C,although it initiates the curing process slightly slower at 110°C.Adding glyoxal to tannin-based adhesives can improve the mechanical properties of composite boards.The wet shear strength of the resulting plywood is increased by 105.4%with the addition of 5-weight percent tannin-based resin with glyoxal as a cross-linker in Soy Protein Adhesive.With glyoxal as a hardener,the panels produced showed good internal bond strengths(>0.35 MPa)and met the international standard specifications for interior-grade panels.

正常小鼠血清通过抑制focal adhesion信号通路减轻小鼠放射性肺炎

目的探讨正常小鼠血清(NMS)对放射性肺炎的治疗作用及可能机制。方法建立胸腔照射诱导的放射性肺炎模型,将小鼠分为对照组、静脉注射血清组、照射组和照射后静脉注射血清组。注射血清组小鼠在照射后立即静脉注射正常小鼠血清100μL,对照组小鼠注射100μL生理盐水,隔天注射1次,共注射8次。照射后15 d取材,HE染色检测肺组织形态学变化,ELISA检测小鼠肺组织和血清中炎症因子肿瘤坏死因子-α(TNF-α)、转化生长因子-β(TGF-β)、白细胞介素-1α(IL-1α)、白细胞介素-6(IL-6)水平;流式细胞术检测肺组织内淋巴细胞比例变化。外泌体miRNA高通量测序探索处理后小鼠的信号通路变化,qRT-PCR检测免疫相关基因的表达水平,使用Western blotting检测黏着斑通路talin-1、tensin 2、FAK、vinculin、α-actinin和paxillin蛋白的表达。结果与照射组相比,照射后注射血清组小鼠肺脏器系数、血清及肺组织上清液中炎症因子TNF-α、TGF-β、IL-1α、IL-6水平显著降低(P<0.05),CD45^(+)、CD4^(+)、T_(reg)淋巴细胞在小鼠肺组织中的浸润程度显著下降(P<0.05);肺中Egfr和Pik3cd的mRNA和蛋白表达水平显著下调,talin-1、tensin 2、FAK、vinculin、α-actinin和paxillin蛋白的表达水平也显著降低(P<0.05)。结论正常小鼠血清通过抑制focal adhesion信号通路关键蛋白的表达减轻电离辐射诱发的小鼠放射性肺炎。

Adhesion of Technical Lignin-Based Non-Isocyanate Polyurethane Adhesives for Wood Bonding

Lignin is the most abundant aromatic natural polymer,and receiving great attention in replacing various petro-leum-based polymers.The aim of this study is to investigate the feasibility of technical lignin as a polyol for the synthesis of non-isocyanate polyurethane(NIPU)adhesives to substitute current polyurethane(PU)adhesives that have been synthesized with toxic isocyanate and polyols.Crude hardwood kraft lignin(C-HKL)was extracted from black liquor from a pulp mill followed by acetone fractionation to obtain acetone soluble-HKL(AS-HKL).Then,C-HKL,AS-HKL,and softwood sodium lignosulfonate(LS)were used for the synthesis of technical lignin-based NIPU adhesives through carbonation and polyamination and silane as a cross-linker.Their adhesion per-formance was determined for plywood.FTIR spectra showed the formation of urethane bonds and the reaction between lignin and silane.The NIPU adhesives prepared with C-HKL showed the highest adhesion strength among the three lignin-based NIPU adhesives.As the silane addition level increased,the adhesion strength of NIPU adhesives increased whereas formaldehyde emission decreased for all NIPU adhesives prepared.These results indicate that NIPU adhesives based on technical kraft lignin have a great potential as polyol for the synth-esis of bio-based NIPU adhesives for wood bonding.

Adhesion strength of tetrahydrofuran hydrates is dictated by substrate stiffness

Understanding the hydrate adhesion is important to tackling hydrate accretion in petro-pipelines.Herein,the relationship between the Tetrahydrofuran(THF)hydrate adhesion strength(AS)and surface stiffness on elastic coatings is systemically examined by experimental shear force measurements and theoretical methods.The mechanical factor-elastic modulus of the coatings greatly dictates the hydrate AS,which is explained by the adhesion mechanics theory,beyond the usual factors such as wettability and structural roughness.Moreover,the hydrate AS increases with reducing the thickness of the elastic coatings,resulted from the decrease of the apparent surface elastic modulus.The effect of critical thickness for the elastic materials with variable elastic modulus on the hydrate AS is also revealed.This study provides deep perspectives on the regulation of the hydrate AS by the elastic modulus of elastic materials,which is of significance to design anti-hydrate surfaces for mitigation of hydrate accretion in petro-pipelines.

Analysis of wheel-rail adhesion redundancy considering the thirdbody medium on the rail surface

Purpose–In response to the problem of insufficient traction/braking adhesion force caused by the existence of the third-body medium on the rail surface,this study aims to analyze the utilization of wheel-rail adhesion coefficient under different medium conditions and propose relevant measures for reasonable and optimized utilization of adhesion to ensure the traction/braking performance and operation safety of trains.Design/methodology/approach–Based on the PLS-160 wheel-rail adhesion simulation test rig,the study investigates the variation patterns of maximum utilized adhesion characteristics on the rail surface under different conditions of small creepage and large slip.Through statistical analysis of multiple sets of experimental data,the statistical distribution patterns of maximum utilized adhesion on the rail surface are obtained,and a method for analyzing wheel-rail adhesion redundancy based on normal distribution is proposed.The study analyzes the utilization of traction/braking adhesion,as well as adhesion redundancy,for different medium under small creepage and large slip conditions.Based on these findings,relevant measures for the reasonable and optimized utilization of adhesion are derived.Findings–When the third-body medium exists on the rail surface,the train should adopt the low-level service braking to avoid the braking skidding by extending the braking distance.Compared with the current adhesion control strategy of small creepage,adopting appropriate strategies to control the train’s adhesion coefficient near the second peak point of the adhesion coefficient-slip ratio curve in large slip can effectively improve the traction/braking adhesion redundancy and the upper limit of adhesion utilization,thereby ensuring the traction/braking performance and operation safety of the train.Originality/value–Most existing studies focus on the wheel-rail adhesion coefficient values and variation patterns under different medium conditions,without considering whether the rail surface with different medium can provide sufficient traction/braking utilized adhesion coefficient for the train.Therefore,there is a risk of traction overspeeding/braking skidding.This study analyzes whether the rail surface with different medium can provide sufficient traction/braking utilized adhesion coefficient for the train and whether there is redundancy.Based on these findings,relevant measures for the reasonable and optimized utilization of adhesion are derived to further ensure operation safety of the train.