Prevalence, clinical characteristics and treatment outcomes of oxyntic gland neoplasm: a single-center retrospective study.

BACKGROUND: Oxyntic gland neoplasm (OGN) is a rare subtype of gastric cancer. The aim of this study is to evaluate the prevalence, clinicopathological features, effectiveness and safety of endoscopic treatment, as well as the prognosis of OGN. METHODS: We retrospectively analyzed the data of patients pathologically diagnosed with OGN at our hospital from November 1, 2019 to May 1, 2023. RESULTS: A total of 36 patients with 45 lesions were identified, resulting in a disease frequency of 0.047% (36/76,832). The mean age was 55.0 ± 7.5 years, with a male-to-female ratio of about 1:1.12. Most lesions were ≤10 mm in size (84.4%), located in the upper third of the stomach (73.3%), exhibited slight elevation (75.5%), appeared whitish (55%), had dilated blood vessels on the surface (75.5%). 16 and 21 lesions were treated by precutting endoscopic mucosal resection (EMR-P) and endoscopic submucosal dissection (ESD), respectively. No significant differences were found between EMR-P and ESD in terms of en bloc resection rate (100% vs 100%, p = 1.000), complete resection rate (100% vs 90.5%, p = 0.495), and curative resection rate (93.8% vs 90.5%, p = 1.000). No complications such as bleeding and perforation were observed. No recurrence or metastasis was observed during the follow-up period. CONCLUSIONS: OGN is a rare tumor with unique clinical, endoscopic, and pathological characteristics. EMR-P and ESD are deemed safe and effective for treating OGNs. The relatively faster and easier EMR-P seems at least non-inferior to ESD, especially for removal of smaller OGNs. The overall prognosis is favorable.

Positioning exercises in improving the quality of magnetic-controlled capsule endoscopy.

BACKGROUND: Good gastric preparation is indispensable for Magnetic-controlled Capsule Endoscopy (MCE) examination, but there is no consensus yet. We aim to explore the clinical application value of positioning exercises in improving the quality of MCE examination. METHODS: Clinical data of 326 patients who underwent MCE examination from January 2020 to December 2023 were collected. The included patients were divided into two groups: the conventional medication preparation group (CMP group, accepted mucosal cleansing medication only) and the positioning exercises group (PE group, accepted mucosal cleansing medication plus positioning exercises). A comparison was made between the two groups in terms of gastric cavity cleanliness score, visibility score, and detection rate of positive lesions. RESULTS: The examination time was (21.29 ± 5.82) minutes in the PE group and (30.54 ± 6.37) minutes in the CMP group, showing a significant difference between the two groups (P < 0.001). The total cleanliness score and visibility score in the CMP group were 15.89 ± 2.82 and 10.93 ± 2.12, respectively. In contrast, the total cleanliness score and visibility score in the PE group were 19.52 ± 2.26 and 15.09 ± 2.31, respectively. The PE group showed significantly better cleanliness scores and visibility scores in all six anatomical regions compared to the CMP group (All P < 0.001). However, there was no significant difference in the detection rate of positive lesions between the two groups (All P > 0.05). CONCLUSION: Positioning exercises before MCE examination can improve the quality of gastric mucosal images and reduce the duration of the examination for patients.

The Analgesic Effect of Ultrasound-guided Erector Spinae Plane Block in Median Sternotomy Cardiac Surgery in Adults: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

OBJECTIVES: To assess the analgesic effect of erector spinae plane block in adults undergoing median sternotomy cardiac surgery. DESIGN AND SETTING: The Cochrane, Embase, and PubMed databases from inception to January 2024 were searched. The study has been registered in the International Prospective Register of Systematic Reviews (CRD42023470375). PARTICIPANTS: Eight randomized controlled trials involving 543 patients, comparing with no block or sham block, were included, whether it was a single injection or continuous. MEASUREMENTS AND MAIN RESULTS: The primary outcomes were pain scores and opioid consumption. Erector spinae plane block reduced pain scores immediately after extubation (mean difference [MD], -1.19; 95% confidence interval [CI], -1.67 to -0.71; p for heterogeneity = 0.10), at 6 hours after extubation (MD, -1.96; 95% CI, -2.85 to -1.08; p for heterogeneity < 0.0001), and at 12 hours after extubation (MD, -0.98; 95% CI, -1.55 to -0.40; p for heterogeneity < 0.00001). The decrease in pain scores reached the minimal clinically important difference within 6 hours. Opioid consumption 24 hours after surgery decreased by 35.72 mg of oral morphine equivalents (95% CI, -50.88 to -20.57; p for heterogeneity < 0.0001). Sensitivity analysis confirmed the stability of results. The quality of primary outcomes was rated as very low to moderate. CONCLUSIONS: Erector spinae plane block decreased pain scores within 12 hours after extubation, reached the minimal clinically important difference within 6 hours, and decreased opioid consumption 24 hours after surgery, based on data of very low to moderate quality. However, high-quality randomized controlled trials are necessary to validate these findings.

Underwater Endoscopic Mucosal Resection Versus Conventional Endoscopic Mucosal Resection for Superficial Non-ampullary Duodenal Epithelial Tumors ≤20 mm: A Systematic Review With Meta-analysis.

BACKGROUND: Underwater endoscopic mucosal resection (UEMR) is increasingly applied in the treatment of superficial non-ampullary duodenal epithelial tumors (SNADETs). This meta-analysis aimed to assess the efficacy and safety of UEMR for SNADETs ≤20 mm in comparison with conventional endoscopic mucosal resection (CEMR). METHODS: The following electronic databases were searched from 2012 until November 20, 2021: PubMed, Embase, Scopus, Web of Science databases, and Cochrane Library. The primary outcomes were the rates of en bloc resection and complete (R0) resection, and the secondary outcomes were procedure time, adverse events (delayed bleeding and delayed perforation), and recurrence rate. RESULTS: A total of 6 studies with 679 lesions (331 underwent UEMR and 348 CEMR) were included in this study. The pooled analysis showed that UMER achieves a similar en bloc resection rate (87.6 vs. 89.9%; odds ratio [OR], 1.29; 95% confidence interval [CI], 0.45 to 3.73; P =0.64; I2 =74%), a similar R0 resection rate (67.3 vs. 73.6%; OR, 1.11; 95% CI, 0.55 to 2.23; P =0.78; I2 =59%), a shorter procedure time (min) (mean difference [MD], -4.05, 95% CI: -6.40 to -1.71; P =0.0007; I2 =70%) compared with CEMR. There were no significant differences in the rates of delayed bleeding, delayed perforation, and recurrence (2.4 vs. 1.7%, 0 vs. 0.6%, 2.2 vs. 4.4%, respectively). CONCLUSION: This meta-analysis demonstrated that UEMR appears to be an effective and safe alternative to CEMR for SNADETs ≤20 mm.

A six-year study of complications related to peripherally inserted central catheters: A multi-center retrospective cohort study in China.

OBJECTIVE: Peripherally inserted central catheters (PICCs), the most frequent central venous catheter, are used to provide medical treatments, although long-term PICC-related adverse outcomes are unknown in China. This study systematically investigated PICC-related complications in four Chinese hospitals. METHODS: Between January 2014 and January 2020, we analyzed the results of 3550 patients with PICC who were referred to four Chinese hospitals. All patients underwent PICC treatment in four Chinese hospitals. Patient-reported signs and symptoms of a putative PICC-related complication or functional were studied. Long-term outcomes and hospitalization costs were also evaluated. RESULTS: An aggregate of 3285 patients were enrolled in the analytic cohort. 58.6% were females and 41.4% were males. The most common reasons for PICC placement included oncologic malignancy and critically ill patients. The majority of PICCs had valved systems (90.7%) and were implanted in the right side (85.5%) and into the basilic vein (87.7%). At least one potential PICC-related problem or adverse effects (AEs) was reported by 67.3% of patients. Central line-associated bloodstream infection (28.1%) and symptomatic deep vein thrombosis (20.7%) were the most common complications. The majority of PICCs were removed for causes other than AEs, with just 723 reported AEs accounting for 22.0% of all PICC removals. The most reasons for PICCs removal were occlusion (425, 12.9%) and exit-site infections (189, 5.8%). CONCLUSIONS: This study is the first retrospective study in our country to explore PICC-related complications. While living with a PICC, more than 67.3% of patients report signs and symptoms of at least one PICC-related problem or adverse impacts, such as difficulties with PICC use and poor effects on physical and social function. In this group, PICCs are safe and effective, although the danger of PICC-related problems should not be disregarded.

Lymphatic Node Metastasis Risk Scoring System: A Novel Instrument for Predicting Lymph Node Metastasis After Thymic Epithelial Tumor Resection.

BACKGROUND: The authors aimed to create a novel model to predict lymphatic metastasis in thymic epithelial tumors. METHODS: Data of 1018 patients were collected from the Surveillance, Epidemiology, and End Results database from 2004 to 2015. To construct a nomogram, the least absolute shrinkage and selection operator (LASSO) regression model was used to select candidate features of the training cohort from 2004 to 2013. A simple model called the Lymphatic Node Metastasis Risk Scoring System (LNMRS) was constructed to predict lymphatic metastasis. Using patients from 2014 to 2015 as the validation cohort, the predictive performance of the model was determined by receiver operating characteristic (ROC) curves. RESULTS: The LASSO regression model showed that age, extension, and histology type were significantly associated with lymph node metastasis, which were used to construct the nomogram. Through analysis of the area under the curve (AUC), the nomogram achieved a AUC value of 0.80 (95 % confidence interval [Cl] 0.75-0.85) in the training cohort and 0.82 (95 % Cl 0.70-0.93) in the validation cohort, and had closed calibration curves. Based on the nomogram, the authors constructed the LNMRS model, which had an AUC of 0.80 (95 % Cl 0.75-0.85) in the training cohort and 0.82 (95% Cl 0.70-0.93) in the validation cohort. The ROC curves indicated that the LNMRS had excellent predictive performance for lymph node metastasis. CONCLUSION: This study established a nomogram for predicting lymph node metastasis. The LNMRS model, constructed to predict lymphatic involvement of patients, was more convenient than the nomogram.

Relationship of possible biomarkers with malignancy of thymic tumors: a meta-analysis.

BACKGROUND: Role of biomarkers for promotion of tumor proliferation (BPTPs) and for promotion of apoptosis (BPAs) in thymic malignant tumors is still unclear. The purpose of this study was to evaluate the relationship between BPTPs and/or BPAs and malignancy of thymic malignant tumors. METHODS: Studies on thymic malignant tumors and biomarkers were searched in PubMed, ISI Web of Knowledge, and Embase databases, and all statistical analyses were conducted using Review Manager. RESULTS: Twelve articles related to biomarkers and thymic malignant tumors were selected and analyzed. A relationship between BPAs and Masaoka stage was demonstrated for four markers, namely Bax, p73, Casp-9 and Bcl-2, included 138 stage I/II patients and 74 stage III/IV patients, and BPAs were significantly correlated with high Masaoka staging (P = 0.03). We further found a relationship between BPAs and degree of malignancy for four markers, namely Bax, p73, Casp-9 and Bcl-2, included 176 thymoma patients and 36 thymic carcinoma patients, and BPAs were significantly correlated with thymic carcinoma (P = 0.010). In addition, a relationship between BPTP and Masaoka staging was demonstrated for seven markers, namely Podoplanin, Glut-1, Muc-1, Egfr, Igf1r, c-Jun, and n-Ras, included 373 patients with stage I/II and 212 patients with stage III/IV, and BPTPs were significantly correlated with high Masaoka staging (P < 0.001). We also found a relationship between BPTPs and degree of malignancy for ten markers, namely Mesothelin, c-Kit (CD117), Egfr, Lat-1, Muc-1,Ema, Glut-1, Igf1r, c-Jun, and n-Ras, included 748 thymoma patients and 280 thymic carcinoma patients, and BPTPs were significantly correlated with thymic carcinoma (P < 0.001). CONCLUSION: These findings show that high levels of BPTPs or BPAs are more closely related to thymic carcinoma and Masaoka stage III/IV, suggesting that BPTPs and BPAs may play an important role in the occurrence and development of thymic malignant tumors.

Expression of fibronectin in esophageal squamous cell carcinoma and its role in migration.

BACKGROUND: Fibronectin (FN) is a high-molecular-weight glycoprotein component of the extracellular matrix involved in cell adhesion, migration, metastasis, proliferation and differentiation, as well as embryogenesis, wound healing, and blood coagulation. Considerable recent research has established that tumor expression of FN is closely associated with tumor formation and development as well as disease prognosis. However, the mechanisms underlying this relationship have remained unclear. The aim of this study was to investigate FN protein expression in esophageal squamous cell carcinoma (ESCC) and determine its potential prognostic relevance, while also elucidating the source and function of FN. METHODS: We conducted immunohistochemical analyses of protein expression in primary tumors of ESCC patients and analyzed their association with standard prognostic parameters and clinical outcomes. Expression of FN in two ESCC cell lines (Eca-109 and TE-1) was also examined by RT-PCR, immunofluorescence, and ELISA. ESCC cells were cultured in a microenvironment containing a high FN content, and changes in their morphology and migration ability were assessed by microscopy, wound-healing assays, and Transwell assays. RESULTS: FN expression in ESCC specimens was mainly detected in the tumor stroma, with very little FN detected in tumor cells. Stromal FN content in ESCC specimens was associated with lymphatic metastasis (P = 0.032) and prognosis. In this latter context, patients with high tumor stromal expression of FN showed worse overall survival (P = 0.002) and progression-free survival (P < 0.001) than those with low expression of FN. Interestingly, FN expression and secretion in ESCC cell lines (Eca-109 and TE-1) was found to be low, but these cells adopted a more migratory phenotype when cultured in vitro in a microenvironment containing high levels of FN. CONCLUSIONS: High FN expression in the stroma of ESCC tumors is closely associated with poor prognosis of patients. High stromal FN content facilitates tumor cell metastasis by promoting morphological changes and improving the motility and migratory ability of ESCC cells.

Insights into the Impact of Surface Hydrophobicity on Droplet Coalescence and Jumping Dynamics.

Droplet coalescence jumping on superhydrophobic surfaces attracts much research attention owing to its capability in enhancing condensation for energy and water applications. In this work, we reveal the impact of the finite surface adhesion to explain velocity discrepancies observed in recent droplet jumping studies, particularly when droplet sizes are a few micrometers (1-10 µm). Surface adhesion, which is usually neglected, can significantly affect both droplet coalescence and departure dynamics. It causes oscillations on velocity and contact area in the droplet coalescence process, as observed numerically and experimentally. Comparing the increasing rate of jumping velocity with contact angle for three different droplet sizes, we show that smaller droplets exhibit higher sensitivity to the change of surface hydrophobicity. We also specify the range of surface superhydrophobicity where the jumping velocity monotonically decreases (θ ≳ 170°), increases (θ ≲ 160°), or changes non-monotonically in transition (160° ≲ θ ≲170°) with droplet size. As a result, there exists a broad jumping velocity range for micrometer-sized droplets on a superhydrophobic surface with a slight contact angle variation. This work offers an extended understanding of the droplet coalescence and jumping dynamics to resolve the discrepancies in recent experimental observations.

Lp-PLA2 silencing protects against ox-LDL-induced oxidative stress and cell apoptosis via Akt/mTOR signaling pathway in human THP1 macrophages.

Atherosclerosis is a disease of the large- and medium-size arteries that is characterized by the formation of atherosclerotic plaques, in which foam cells are the characteristic pathological cells. However, the key underlying pathomechanisms are still not fully elucidated. In this study, we investigated the role of lipoprotein-associated phospholipase A2 (Lp-PLA2) in ox-LDL-induced oxidative stress and cell apoptosis, and further, elucidated the potential machanisms in human THP1 macrophages. Flow cytometry and western blot analyses showed that both cell apoptosis and Lp-PLA2 expression were dose-dependently elevated after ox-LDL treatment for 24 h and also time-dependently increased after 50 mg/L ox-LDL incubation in THP1 macrophages. In addition, Lp-PLA2 silencing decreased ox-LDL-induced Lp-PLA2 and CD36 expression in THP1 macrophages. We also found that the levels of oil red O-staining, triglyceride (TG) and total cholesterol (TC) were significantly upregulated in ox-LDL-treated THP1 cells, but inhibited by Lp-PLA2 silencing. Furthermore, ox-LDL treatment resulted in significant increases of ROS and MDA but a marked decrease of SOD, effects that were reversed by Lp-PLA2 silencing in THP1 cells. Lp-PLA2 silencing reduced ox-LDL-induced cell apoptosis and caspase-3 expression in THP1 cells. Moreover, Lp-PLA2 siRNA transfection dramatically lowered the elevated levels of p-Akt and p-mTOR proteins in ox-LDL-treated THP1 cells. Both PI3K inhibitor LY294002 and mTOR inhibitor rapamycin decreased the augmented caspase-3 expression and TC content induced by ox-LDL, respectively. Taken together, these results revealed that Lp-PLA2 silencing protected against ox-LDL-induced oxidative stress and cell apoptosis via Akt/mTOR signaling pathway in human THP1 macrophages.

The anti-fibrotic effects of microRNA-153 by targeting TGFBR-2 in pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial fibrotic lung disease with an undefined etiology and no effective treatments. By binding to cell surface receptors, transforming growth factor-ß (TGF-ß) plays a pivotal role in lung fibrosis. Therefore, the screening of microRNAs (miRNAs), especially those interrupting the effects of TGF-ß, may provide information not only on the pathomechanism, but also on the treatment of this disease. In the present study, we found that miR-153 expression was dysregulated in the lungs of mice with experimental pulmonary fibrosis and TGF-ß1 decreased miR-153 expression in pulmonary fibroblasts. Moreover, increased miR-153 levels attenuated, whereas the knock down of miR-153 promoted the pro-fibrogenic activity of TGF-ß1, and miR-153 reduced the contractile and migratory activities of fibroblasts. In addition, TGFBR2, a transmembrane serine/threonine kinase receptor for TGF-ß, was identified as a direct target of miR-153. Furthermore, by post-transcriptional regulation of the expression of TGFBR2, phosphorylation of SMAD2/3 was also influenced by miR-153. These data suggest that miR-153 disturbs TGF-ß1 signal transduction and its effects on fibroblast activation, acting as an anti-fibrotic element in the development of pulmonary fibrosis.

Ischemic neurons activate astrocytes to disrupt endothelial barrier via increasing VEGF expression.

Blood-brain barrier (BBB) disruption occurring within the first few hours of ischemic stroke onset is closely associated with hemorrhagic transformation following thrombolytic therapy. However, the mechanism of this acute BBB disruption remains unclear. In the neurovascular unit, neurons do not have direct contact with the endothelial barrier; however, they are highly sensitive and vulnerable to ischemic injury, and may act as the initiator for disrupting BBB when cerebral ischemia occurs. Herein, we employed oxygen-glucose deprivation (OGD) and an in vitro BBB system consisting of brain microvascular cells and astrocytes to test this hypothesis. Neurons (CATH.a cells) were exposed to OGD for 3-h before co-culturing with endothelial monolayer (bEnd 3 cells), or endothelial cells plus astrocytes (C8-D1A cells). Incubation of OGD-treated neurons with endothelial monolayer alone did not increase endothelial permeability. However, when astrocytes were present, the endothelial permeability was significantly increased, which was accompanied by loss of occludin and claudin-5 proteins as well as increased vascular endothelial growth factor (VEGF) secretion into the conditioned medium. Importantly, all these changes were abolished when VEGF was knocked down in astrocytes by siRNA. Our findings suggest that ischemic neurons activate astrocytes to increase VEGF production, which in turn induces endothelial barrier disruption.

Contribution of nestin positive esophageal squamous cancer cells on malignant proliferation, apoptosis, and poor prognosis.

BACKGROUND: The stem cell-associated intermediate filament nestin has recently been linked with neoplastic transformation, but the specific mechanism by which nestin positive tumor cells leads to malignant invasion and metastasis behaviors of esophageal squamous cell carcinoma (ESCC) remains unclear. METHODS: To obtain insight into the biological role of nestin in ESCC, we explored the association of the nestin phenotype with malignant proliferation and apoptosis in esophageal squamous cancer cells. Nestin expression was determined in ESCC specimens and cell lines, and correlated with clinicopathological properties, including clinical prognosis and proliferative markers. The association of the nestin phenotype with apoptotic indicators was also analyzed. RESULTS: Nestin was expressed in ESCC specimens and cell lines. ESCC patients with nestin-positive tumors had significantly shorter median survival and progression-free survival times than those with nestin-negative tumors. Positive staining for the proliferation markers Ki67 and PCNA (proliferating cell nuclear antigen) was detected in 56.9% and 60.2% of ESCC specimens, respectively, and was strongly correlated with the nestin phenotype. Notably, expression of cyclin dependent kinase-5 (CDK5) and P35 was detected in 53.8% and 48.4% of ESCC specimens, respectively, and was strongly associated with the nestin phenotype. CONCLUSION: Our data demonstrated nestin expression in ESCC specimens and cell lines, and revealed a strong association of the nestin phenotype with poor prognosis in ESCC patients. Furthermore, we showed that nestin positive ESCC cells played an important role in the malignant proliferation and apoptosis.

Dynamic Thermal Response of Multiple Interface Cracks between a Half-Plane and a Coating Layer under General Transient Temperature Loading.

This paper explores the thermal behavior of multiple interface cracks situated between a half-plane and a thermal coating layer when subjected to transient thermal loading. The temperature distribution is analyzed using the hyperbolic heat conduction theory. In this model, cracks are represented as arrays of thermal dislocations, with densities calculated via Fourier and Laplace transformations. The methodology involves determining the temperature gradient within the uncracked region, and these calculations contribute to formulating a singular integral equation specific to the crack problem. This equation is subsequently utilized to ascertain the dislocation densities at the crack surface, which facilitates the estimation of temperature gradient intensity factors for the interface cracks experiencing transient thermal loading. This paper further explores how the relaxation time, loading parameters, and crack dimensions impact the temperature gradient intensity factors. The results can be used in fracture analysis of structures operating at high temperatures and can also assist in the selection and design of coating materials for specific applications, to minimize the damage caused by temperature loading.

Analysis of nonlinear bending behavior of nano-switches considering surface effects.

Nano-switch structures are important control elements in nanoelectromechanical systems and have potential applications in future nanodevices. This paper analyzes the effects of surface effects, geometric nonlinearity, electrostatic forces, and intermolecular forces on the nonlinear bending behavior and adhesion stability of nano-switches. Based on the Von Karman geometric nonlinearity theory, four types of boundary conditions for the nano-switch structure were specifically calculated. The results show that surface effects have a significant impact on the nonlinear bending and adhesion stability of nano-switches. Surface effects increase the adhesion voltage of the nano-switch and decrease its adhesion displacement, and as the size of the nano-switch structure increases, the impact of surface effects decreases. A comparative analysis of the linear theory and the nonlinear theory results shows that the adhesion voltage predicted by the linear theory is smaller than that predicted by the nonlinear theory. The effect of geometric nonlinearity increases as the size of the nano-switch structure increases, as the distance between the electrodes increases, and as the aspect ratio of the nano-switch structure increases. These findings provide theoretical support and reference for the design and use of future nanodevices and nanoelectromechanical systems.

In-situ induced formation of Fe-OM association in soil: Theory and practice of remediation of cadmium contaminated paddy fields in high cadmium geological background areas.

Cadmium (Cd) pollution in rice paddies, attributable to high geological Cd backgrounds, has emerged as a global concern. This study leverages the passivation mechanism of bioavailable Cd by iron-organic matter associations (Fe-OM) to explore a novel strategy for Cd immobilization. We examined the adsorptive capacity and removal efficiency of Cd by laccase-mediated Fe-OM association and assessed their natural stability using 57Fe isotopic tracing. Additionally, we conducted in-situ remediation trials in a Cd-enriched paddy soil. Our results indicate that the theoretical maximum adsorption capacity for Cd by the laccase-mediated Fe-OM is 100.0 mg/g, which is a 15% improvement over the common Fe-OM and a 150% enhancement over inorganic iron oxides (ferrihydrite). The 57Fe isotope tracing test showed that the affinity of laccase-modified organic matter for iron increased by 55.6%, and it exhibited better stability than common Fe-OM under anaerobic conditions. The field-scale remediation, predicated on the in situ synthesis of Fe-OM association, effectively reduced the bioavailable Cd concentration in the soil from 0.91 mg/kg to 0.40 mg/kg. Concurrently, the Cd concentration in rice grains was lowered from 0.63 mg/kg to 0.15 mg/kg, thus falling beneath the national safety threshold. This study represents a significant advancement in the safe reclamation and utilization of agricultural soils with elevated geological Cd burdens.

Observer-based hierarchical distributed model predictive control for multi-linear motor traction systems.

This paper proposes an observer-based hierarchical distributed model predictive control (MPC) strategy for ensuring speed consistency in multi-linear motor traction systems. First, a communication topology is considered to ensure information exchange. Secondly, the control architecture of each agent is divided into upper layers and lower layers. The upper layer utilizes a distributed MPC method to track the leader's speed. The lower layer uses a decentralized MPC method to track the command signals sent by its upper layer controller. In addition, to eliminate the negative impact of disturbance, a nonlinear disturbance observer is designed. We then prove the asymptotic stability of the entire system by properly designing the Lyapunov equation. Finally, the feasibility of the proposed strategy is verified based on several simulations.