Inverse Analysis Research Articles

Combining machine learning and physics modeling to determine the geostress of reservoirs in real-time

Real-time updating of geological properties in reservoirs through monitoring data is critical for optimizing hydraulic fracturing. In this work, the ML-Physics method, which inherits the advantages of machine learning (ML) and physical modeling, has been developed to determine the geological parameters with limited computational time, including far-field geostress, geostress in the vicinity of faults and rock material properties. The ML-Physics method consists of two stages: the preparation stage and the operation stage. During the preparation stage, which occurs before the in situ operation and is not constrained by computational time limitation, a surrogate artificial neural network (ANN) model is established. This ANN model captures the implicit relationship between geological parameters and monitoring data. During the operational stage, which is constrained by real-time requirements for the convenience of engineers in field work, inverse analysis with physical modeling and the surrogate ANN model is employed to determine geological parameters. In the context of ML-Physics method, the initial values of inverse iteration are chosen based on surrogate ANN results. The obtained geological parameters can be used for hydraulic fracturing analysis. This ML-Physics method demonstrates superior performance in terms of both accuracy and computational efficiency.

Research on Pose Error Modeling and Compensation of Posture Adjustment Mechanism Based on WOA-RBF Neural Network

This paper is aimed to address the issue of decreased accuracy in the ship block docking caused by the structural errors of posture adjustment mechanism. First, inverse kinematic analysis is performed to investigate the sources of static errors in the mechanism. Subsequently, based on the closed-loop vector method, a pose error model for the moving platform is established, which includes eight categories of error terms. The impact of various structural errors on the pose accuracy of the moving platform is then compared and analyzed under both single-limb and multi-limb configurations. Therefore, a compensation method based on the whale optimization algorithm optimized radial basis function neural network is proposed. By transforming pose errors into actuator length errors, it establishes a predictive model between the theoretical pose of the dynamic platform and actuator length errors. After optimizing the network parameters, it yields the actuator length compensation to correct the actual pose of the dynamic platform. Simulation and experimental results validate the effectiveness of this method in enhancing the motion accuracy of the parallel mechanism. The mean pose accuracy of the moving platform is improved by 85.07%, demonstrating a significant compensation effect.

Acoustic source reconstruction of a commercial generator set using inverse pellicular modes and inverse numerical panel contribution analysis

Many methods have been used to reconstruct a noise source from measured sound pressure information in the field. Most of these approaches are used for source visualization. However, the inverse boundary and finite element methods are reconstruction methods that are more useful for sound field predictions. The current research examines two inverse numerical simulation approaches, inverse pellicular modes analysis and inverse numerical panel contribution analysis, which are variations of the inverse finite element method. The first of these relates the sound pressure in the field to pellicular modes. Pellicular modes are generated by adding a thin layer of acoustic finite elements around the boundary and determining the acoustic modes in that thin layer. These nonphysical modes are then used as if they were structural modes and serve as the basis functions for the reconstruction. The second method divides the boundary surface of the source into sets of panels. Transfer functions can be calculated relating the panel vibration to the sound pressure at the measurement locations. These transfer functions are the basis functions for the reconstruction. In the current work, both inverse pellicular modes analysis and inverse numerical panel contribution analysis are used to reconstruct a commercial generator source and to predict the sound pressure level 7.0 m away from the source. The number of measurements required for an adequate reconstruction is investigated for both methods. The results suggest that both methods can be used to reconstruct a complicated source

Preferred input-output analysis using inverse DEA: an application to retailer performance assessment

Inverse data envelopment analysis (DEA) approach deals with the input or output estimation preserving relative efficiency score. In many real-world applications, there is more prior information like price information or managerial preferences, etc. that should be considered in the efficiency analysis. Corporation of this sort of information is not dealt with in the inverse DEA literature, not in the input estimation process nor in the output estimation. Thus, the current paper develops a new inverse DEA model capable of dealing with prior information via weight restrictions. Proposed models are applied in the efficiency and inverse efficiency analysis of a real-world retailer application.

Random Forest Model-based Aerosol Optical Depth Inversion and Variation Analysis in China

Random Forest Model-based Aerosol Optical Depth Inversion and Variation Analysis in China

The impact of GLP-1 receptor agonists on postoperative outcomes following total shoulder arthroplasty

BackgroundTotal Shoulder Arthroplasty (TSA) is a commonly performed orthopedic procedure for shoulder arthritis. Type II Diabetes Mellitus (T2DM) has been associated with negative postoperative outcomes following TSA. Glucagon-like peptide-1 receptor (GLP-1) agonists are increasingly popular drugs that have proven to be effective in the management of T2DM. To date, there is no study evaluating the complication profile following TSA of patients taking GLP-1 agonists. MethodsA retrospective cohort analysis was conducted on patients from the TriNetX Database who underwent TSA between January 2018 and December 2023. All patients had a diagnosis of T2DM at the time of index procedure. Patients were stratified into two groups according to their GLP-1 agonist prescription status. Medical complications that occurred within 90 days and surgical complications that occurred within 2 years of index procedure were collected. A univariate logistic regression analysis was conducted to examine the initial connection between the active use of GLP-1 agonists and postoperative outcomes. Subsequently, an inverse propensity score-weighted binary logistic regression was used to adjust for potential biases. ResultsA total of 8254 patients met our inclusion criteria. The “non-GLP-1” and “GLP-1” groups included 7749 and 505 patients, respectively. The use of GLP-1 agonists did not incur increased risk of any medical or surgical complications following TSA. Our unadjusted analysis demonstrated that the use of GLP-1 agonists was significantly associated with lower odds of mortality within 90 days of surgery (OR 0.17, 95% CI 0.0043-0.99, P = .0435). GLP-1 agonist use was associated with decreased risk of mortality within 90 days when subjected to inverse propensity score-weighted analysis (OR 0.077, 95% CI 0.011-0.554, P = .011). The use of GLP-1 agonists was not a predictor for any other medical or surgical complications in inverse-propensity score weighted-analysis, although decreased risk of wound dehiscence approached significance (OR 0.256, 95% CI 0.061-1.074, P = .063). ConclusionPreoperative GLP-1 agonist use is associated with reduced 90-day mortality in T2DM patients undergoing TSA, without increasing other postoperative complications. These findings support the continued use of GLP-1 agonists in perioperative management to optimize surgical outcomes in this patient population.

Simulation inversion analysis of simultaneous commutation failure of Zhaoyi and Yindong DC

Abstract Aim at the three times simultaneous commutation failure of two Multi-outfeed and Multi-infeed DC Systems in a Similar Path of Ningxia, the Ningxia power grid model is built in Power System Analysis Software Package (PSASP) with actual parameters, and the accident inversion simulation is carried out based on the operation state of the power grid before the fault. Based on the inversion simulation, the simulation results were compared with the measured PMU data. The results showed that the trend of simulation and the measured curve is consistent, and the simulation was slightly more serious than the actual fault, but the overall error was less than 10%, which verified the accuracy of the simulation model and method, and provided a basis for the subsequent simulation analysis of the power grid operation mode.

3-D inversion of gravity and magnetic data and its application in the study on the characteristics of magmatic rocks in the Yin’e Basin and adjacent areas

Abstract Magmatic rocks are crucial in studies of tectonic evolution and hydrocarbon generation and reservoir formation. To elucidate the distribution characteristics of subsurface rocks in the Yin’e Basin, the study utilizes the method of the weighted physical property inversion of random subdomains to conduct a three-dimensional inversion analysis of gravity and magnetic data. The findings indicate that magmatic rocks are predominantly located in the western and southeastern regions. Regional faults significantly influence the distribution of magnetic rocks in the Yin’e Basin. In the eastern part, magmatic rocks are generally larger and predominantly aligned in a northeast-southwest direction, whereas in the western part, they are oriented northwest-southeast, aligning with the tectonic framework of the study area. Intermediate-basic rocks are primarily distributed along fault belts and uplift zones, while acidic rocks are concentrated in depression zones. These results provide substantial insights into the distribution patterns of magmatic rocks and hold significant implications for oil and gas geological exploration in the Yin’e Basin.

Outcomes of different anesthesia techniques in nonagenarians treated with mechanical thrombectomy for anterior circulation large vessel occlusion: An inverse probability weighting analysis.

There is a lack of evidence for the optimal type of anesthesia technique in patients ⩾ 90 years with acute ischemic stroke undergoing mechanical thrombectomy (MT) as this subgroup of patients was often excluded or under-represented in previous trials. We aimed to compare outcomes between general anesthesia (GA) and non-GA techniques in patients ⩾ 90 years with large vessel occlusion (LVO) undergoing MT. Our study included patients ⩾ 90 years with anterior circulation LVO, NIHSS ⩾ 6, ASPECTS ⩾ 5 consecutively treated with MT within 6 h after stroke onset in three thrombectomy capable centers between January 1st, 2016 and March 30th, 2023. Inverse probability weighting (IPW) was used to reduce bias by indication of the anesthesia type on study outcomes. We used a weighted ordinal robust logistic regression analysis to explore the primary outcome of modified Rankin Scale (mRS) shift at 90 days in GA versus non-GA treated patients. Secondary outcomes included 90-day mortality, symptomatic intracranial hemorrhage (sICH) and TICI score of 2b, 2c, or 3. We included 139 patients ⩾ 90 years treated with MT, 62 were in GA group and 77 in non-GA group. There was a significant shift for worse mRS scores at 90-day in non-GA treated patients (cOR 3.65, 95% CI 1.77-7.77, p = 0.001). The weighted logistic regression showed that non-GA technique was an independent predictor of 90-day mortality (OR 7.49, 95% CI 2.00-28.09; p = 0.003). Our study indicated that nonagenarians with acute ischemic stroke treated with MT without GA have a worse prognosis than their counterparts undergoing MT with GA. Further studies in larger cohorts are warranted to evaluate the optimal type of anesthesia in this patient population.

Nonalcoholic fatty liver disease and colorectal cancer: a two-sample bidirectional Mendelian randomization analysis.

Observational studies suggest a connection between nonalcoholic fatty liver disease (NAFLD) and colorectal cancer (CRC) risk. It, however, remains unclear whether such a connection is causal. This study aims to examine the association between NAFLD and CRC using a two-sample bidirectional Mendelian randomization (MR) method. Summary statistics for NAFLD were obtained from four genome-wide association studies, including 8434 cases and 770 180 controls. Meanwhile, CRC and controls (1803 vs. 174 006) were collected from the FinnGen. The inverse variance weighted (IVW) method was used primarily, while sensitivity analyses were conducted via the weighted median, MR Egger method, simple mode, and weighted mode to enhance result reliability. We found a positive correlation between NAFLD and CRC by IVW method in the forward MR analysis (odds ratio = 1.270, 95% confidence interval: 1.154-1.398, P = 1.092 × 10-6). Inverse MR analysis, however, suggested that CRC may not have a causal effect on NAFLD. Besides, we observed an absence of horizontal pleiotropy and heterogeneity in this MR analysis. Our forward MR study found that NAFLD may increase CRC risk. In contrast, CRC may not have a causal relationship with NAFLD. This study provides genetic evidence supporting a cause-and-effect association between NAFLD and CRC.

Characterization of Natural Gas Hydrate Constrained by Well and Seismic Data in Qiongdongnan Basin

This study investigates the natural gas hydrates within the Qiongdongnan Basin by integrating well-log and seismic data. Through pre-stack inversion and rock physics analysis, key parameters such as P-wave and S-wave impedances were utilized to distinguish hydrate-bearing formations from other geological bodies. A low-frequency model was constructed using the Inverse Distance Weighting (IDW) algorithm to improve the precision of parameter inversion. This study employs a multi-constraint inversion strategy, incorporating hard constraints from multiple wells and soft constraints from geological frameworks, ensuring reliable inversion results. Findings indicate that hydrate reservoirs are characterized by increased wave velocity and density due to hydrate accumulation, providing insights into the spatial distribution and characteristics of hydrates. This research enhances the understanding of hydrate reservoirs and offers valuable data for exploration in the Qiongdongnan Basin.

Investigation of a Pathogenic Inversion in UNC13D and Comprehensive Analysis of Chromosomal Inversions Across Diverse Datasets.

Inversions are known contributors to the pathogenesis of genetic diseases. Identifying inversions poses significant challenges, making it one of the most demanding structural variants (SVs) to detect and interpret. Recent advancements in sequencing technologies and the development of publicly available SV datasets have substantially enhanced our capability to explore inversions. However, a cross-comparison in those datasets remains unexplored. In this study, we reported a proband with familial hemophagocytic lymphohistiocytosis type-3 carrying c.1389+1G>A in trans with NC_000017.11:75576992_75829587inv disrupting UNC13D , an inversion present in 0.006345% of individuals in gnomAD(v4.0). Based on this result, we investigate the features of potentially pathogenic inversions in public datasets. 98.9% of inversions are rare in gnomAD, and they disrupt 5% of protein-coding genes associated with a phenotype in OMIM. We then conducted a comparative analysis of the datasets, including gnomAD, DGV, and 1KGP, and two recent studies from the Human Genome Structural Variation Consortium revealed common and dataset-specific inversion characteristics suggesting methodology detection biases. Next, we investigated the genetic features of inversions disrupting the protein-coding genes by classifying the intersections between them into three categories. We found that most of the protein-coding genes in OMIM disrupted by inversions are associated with autosomal recessive phenotypes regardless of categories supporting the hypothesis that inversions in trans with other variants are hidden causes of monogenic diseases. This effort aims to fill the gap in our understanding of the molecular characteristics of inversions with low frequency in the population and highlight the importance of identifying them in rare disease studies.

Causal role of immune cells in muscle atrophy: mendelian randomization study

Immune system and inflammation had a great influence on the progression of muscle atrophy. However, the causal relationship with specific immune cell traits remained uncertain. The aim of this study was to elucidate the genetic influences on these associations, providing insights into the underlying mechanisms of muscle atrophy. A bidirectional two-sample Mendelian randomization (MR) analysis was conducted to investigate the causal relationship between immune cell phenotypes and muscle atrophy. Data on immune cell phenotypes were obtained from a research cohort containing data on 731 immune cell phenotypes and data on muscle atrophy were sourced from a Finnish database. MR analysis was performed using the MR-Egger method, weighted median, inverse variance weighting, heterogeneity testing, sensitivity analysis, and multiplicity analysis, with results subjected to false discovery rate(FDR) correction. Additionally, the UK Biobank cohort was utilized as an external validation. A total of 31 immune phenotypes with causal relationships with muscle atrophy were identified, including various phenotypes of conventional dendritic cells, myeloid cells, T cells/B cells/natural killer cells, regulatory cells, and T cell maturation stages. Among them, 12 immune phenotypes were identified as exhibiting a positive causal relationship with muscle atrophy, while 19 immune phenotypes were demonstrated to have a negative causal association, highlighting the complex interactions between immune cells and muscle health. The results of the reverse MR analysis indicated that a negative correlation between muscle atrophy and CD28 on secreting Treg (OR = 0.9038, 95%CI:0.8308 ~ 0.9832, P = 0.0186). A significant positive correlation was revealed by external datasets between the CD25 on IgD + CD38- immune phenotype and the risk of muscle atrophy, which was consistent with the trend observed in the training group (OR = 1.1041, 95% CI: 1.1005–1.1076, P = 0.0263). No evidence of pleiotropy was observed, and the reliability of these findings was demonstrated by the leave-one-out analysis. The findings highlight significant correlations between certain immune cell features and muscle atrophy, providing potential targets for further investigation of immunological mechanisms and therapeutic interventions for this condition.

Prognostic implications of N-terminal pro-brain natriuretic peptide in patients with Non-ST segment elevation myocardial infarction

Abstract Background Limited data exist regarding prognostic implications of N-terminal pro-Brain Natriuretic Peptide (NT-proBNP) in patients with non-ST segment elevation myocardial infarction (NSTEMI) who underwent percutaneous coronary intervention (PCI). Objectives The current study sought to evaluate the prognostic implications of NT-proBNP in patients with NSTEMI who underwent PCI. Methods Among a total of 13,104 patients from a nationwide, multicenter, and prospective registry of the Korea Acute Myocardial Infarction Registry-National Institutes of Health (KAMIR-NIH), a total of 3,083 patients with NSTEMI who underwent PCI were selected. The selected patients were classified according to the initial NT-proBNP value (cut-off value of NT-proBNP, 700 pg/ml). Primary endpoint was major adverse cardiovascular events (MACE) at 3 years, a composite of all-cause death, recurrent myocardial infarction (MI), unplanned repeat revascularization, and admission for heart failure. Results Among the study population, 1,813 patients (58.8%) were in the low NT-proBNP group (<700 pg/ml) and 1,270 patients (41.2%) were in the high NT-proBNP group (≥700 pg/ml). The high NT-proBNP group showed significantly higher risk of MACE than the low NT-proBNP group (29.5% vs 12.3%; adjusted hazard ratio [HR], 1.69; 95% confidence interval [CI], 1.39-2.07; P<0.001), mainly driven by higher risk of cardiac death or admission for heart failure (15.6% vs. 2.2%; adjusted HR, 2.98; 95% CI, 2.03-4.40; P<0.001). These results were consistent after confounder adjustment by propensity score matching (HR, 1.56; 95% CI, 1.21-2.02; P=0.001) and inverse probability weighting analysis (HR, 1.54; 95% CI, 1.19-2.00; P=0.001). Conclusion In patients with NSTEMI who underwent PCI, elevated initial NT-proBNP level was associated with higher risk of MACE at 3 years, mainly driven by the higher risk of cardiac death or admission for heart failure. The current results suggest that the initial NT-proBNP level may have a clinically significant prognostic value in NSTEMI patients undergoing PCI.

Dynamic Inverse Analysis of Steel–Concrete Hybrid Wind Turbine Tower

The steel–concrete hybrid tower (SCHT) has been popularized as the supporting structure for onshore wind turbines to meet the increasing hub height and rotor diameter. The internal force of the cross-section, which is the prerequisite of the structural design, is based on the load analysis. However, the nonignorable effect of the second-order gravity makes analyzing the external load of the supporting tower a coupled problem, especially for the SCHT, which is higher than a conventional steel tubular tower. Besides, the aerodynamic load of the wind turbine, the main excitation acting on the supporting tower, is usually computed by numerical methods and lack of validation. To optimize the analysis method for the internal force of the SCHT, one feasible approach is evaluating the external excitation directly. Based on the theory of the Kalman filter, this study develops a dynamic inverse method of the SCHT. It aims to estimate the horizontal thrust of the wind turbine and provide an overall evaluation of the dynamic responses of the SCHT by using the measured dynamic responses at the limited point on the SCHT. A rigorous numerical simulation based on ABAQUS is conducted to generate the dynamic responses of the SCHT, which are used to validate the effectiveness of the proposed method. It also investigated the influence of observation type, number of measuring points, and noise level on the estimation accuracy.

Functional investigation and two-sample Mendelian randomization study of primary biliary cholangitis hub genes.

The identification of specific gene expression patterns is crucial for understanding the mechanisms underlying primary biliary cholangitis (PBC) and finding relevant biomarkers for diagnosis and therapeutic evaluation. To determine PBC-associated hub genes and assess their clinical utility for disease prediction. PBC expression data were obtained from the Gene Expression Omnibus database. Overlapping genes from differential expression analysis and weighted gene co-expression network analysis (WGCNA) were identified as key genes for PBC. Kyoto Encyclopedia of Genes and Genomes and Gene Ontology analyses were performed to explore the potential roles of key genes. Hub genes were identified in protein-protein interaction (PPI) networks using the Degree algorithm in Cytoscape software. The relationship between hub genes and immune cells was investigated. Finally, a Mendelian randomization study was conducted to determine the causal effects of hub genes on PBC. We identified 71 overlapping key genes using differential expression analysis and WGCNA. These genes were primarily enriched in pathways related to cytokine-cytokine receptor interaction, and Th1, Th2, and Th17 cell differentiation. We utilized Cytoscape software and identified five hub genes (CD247, IL10, CCL5, CCL3, and STAT3) in PPI networks. These hub genes showed a strong correlation with immune cell infiltration in PBC. However, inverse variance weighting analysis did not indicate the causal effects of hub genes on PBC risk. Hub genes can potentially serve as valuable biomarkers for PBC prediction and treatment, thereby offering significant clinical utility.

Inverse dynamics analysis of 4-DOF stacking robot with closed chain structure

A four-degree-of-freedom PR1300 stacking robot with two parallel quadrilateral structures connected in series at the shoulder was designed. The hybrid robot with local closed chains has the characteristics of compact structure, high stiffness, and high modularity. To solve the dynamic problem of the hybrid robot. Firstly, by analyzing the induced relationship between joints, the stacking robot with a local closed chain structure is transformed into two branch chain mechanisms, and the kinematic model of the robot is established using the D-H parameter method. Secondly, the Kane method is applied to model the dynamics of the two branch chains separately, and the rigid body dynamics Kane equation of the entire 4-DOF stacking robot with a closed chain structure is obtained through the augmented matrix. Finally, the SolidWorks Motion mechanical simulation platform and MATLAB software were used to program dynamic simulations and numerical calculations, and the results were compared to verify the correctness of the dynamic theory derivation. This theory provides a necessary theoretical basis for the subsequent synthesis of robot dynamic scales.

Causal relationship between amino acids and ovarian cancer in the European population: A bidirectional Mendelian randomization study and meta-analysis.

In recent years, an increasing number of observational studies have reported the impact of amino acids on ovarian cancer. However, Mendelian randomization studies have not yet been conducted to explore the causal relationship between them in the context of ovarian cancer. This study conducted Mendelian randomization (MR) analysis of 20 amino acids in relation to ovarian cancer data from 2 different sources within the European population, using a two-sample MR approach. The primary results from the inverse variance weighting analysis were then subjected to a meta-analysis, followed by multiple testing correction for the meta-analysis thresholds. Finally, reverse causality testing was performed on the positively associated amino acids and ovarian cancer. MR analyses were conducted for 20 amino acids with ovarian cancer data from both the Finngen R10 and Open genome-wide association study databases. The inverse variance weighted results from these 2 analyses were then combined through meta-analysis, with multiple corrections applied to the significance thresholds of the meta-analysis results. The findings showed that only cysteine had a significant association with ovarian cancer, with an (odds ratio) odds ratio value of 0.507 (95% confidence interval: 0.335-0.767, P = .025). The P-value of the combined MR and meta-analysis, after multiple testing correction, was 0.025, indicating statistical significance (P < .05). Additionally, cysteine did not show a reverse causal relationship with ovarian cancer in either data source. Cysteine is a protective factor for ovarian cancer, potentially reducing the risk of ovarian cancer and slowing the progression of the disease.

Low-Dose Prasugrel vs. Standard-Dose Clopidogrel for Patients Undergoing Percutaneous Coronary Intervention

Low-dose prasugrel (3.75 mg) is used as maintenance therapy for percutaneous coronary intervention; however, data on long-term outcomes are scarce.Methods and Results: We analyzed 5,392 participants in the KiCS-PCI registry who were administered low-dose prasugrel or clopidogrel at discharge between 2008 and 2018 and for whom 2-year follow-up data were available. We adjusted for confounders using matching weight analyses and multiple imputations. Similarly, we used inverse probability- and propensity score-weighted analyses. We also performed instrumental variable analyses. The primary outcomes were acute coronary syndrome (ACS) and bleeding requiring readmission. Secondary outcomes were all-cause death and a composite outcome of ACS, bleeding, heart failure, stroke, coronary bypass requiring admission, and all-cause death. In this cohort, 12.2% of patients were discharged with low-dose prasugrel. Compared with clopidogrel, low-dose prasugrel was associated with a reduced risk of ACS (hazard ratio [HR] 0.58; 95% confidence interval [CI] 0.39-0.85), bleeding (HR 0.62; 95% CI 0.40-0.97), and the composite outcome (HR 0.71; 95% CI 0.59-0.86). Inverse probability-weighted analysis yielded similar results; however, matching weight analysis without multiple imputations and propensity score-matched analyses showed similar outcomes in both groups. Instrumental variable analyses showed reduced risks of ACS and composite outcome for those on low-dose prasugrel. All-cause mortality did not differ in all analyses. Low-dose prasugrel demonstrates comparable outcomes to clopidogrel in terms of ACS and bleeding.

Perioperative intervention of dysphagia rehabilitation team in older adults with gastric cancer: An inverse probability weighting analysis

IntroductionThis study aimed to evaluate the efficacy of perioperative dysphagia rehabilitation in older adult patients diagnosed with gastric cancer who underwent gastrectomy. Materials and MethodsThis retrospective study included 149 patients over 80 years who underwent gastrectomies between January 2000 and December 2020. The patients were divided into two groups based on the intervention of the dysphagia rehabilitation team (DRT group: n = 101) and the non-intervention control group (C group: n = 48). Inverse probability weighting (IPW) analysis was used to reduce bias caused by potential confounding. ResultsThe incidence of overall complications was significantly lower in the DRT group (odds ratio [OR]; 0.27[0.08–0.93]), among which the incidence of postoperative pneumonia (OR; 0.07[0.01–0.43]) and aspiration pneumonia (OR; 0.05[0.01–0.44] was significantly reduced. Ten patients developed postoperative pneumonia; seven were in the C group, and three were in DRT group. Sixty percent of these patients had preoperative comorbidities related to the respiratory system. Regarding the time of onset of aspiration pneumonia, two patterns were observed: onset within a short period after surgery and onset after the start of eating. In contrast, five patients underwent preoperative dysphagia rehabilitation in the DRT group. Among them, postoperative aspiration pneumonia was prevented in four patients, and the others were prevented from severe pneumonitis by the intervention of the dysphagia rehabilitation team. DiscussionPerioperative intervention in dysphagia rehabilitation is not only associated with reduced postoperative pneumonia but also creates awareness in the medical staff and promotes careful observation of swallowing in patients, thereby controlling the incidence of postoperative pneumonia. The perioperative intervention of the dysphagia rehabilitation team is useful for older adult patients with gastric cancer.