17062 research outputs found
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確率的余震予測手法パラメータの早期同定手法の高度化 -地震検知能力の時間空間的変化によるデータ拡張を反映した機械学習手法-
Get PDFapplication/pdf生物資源学研究科 共生環境学専攻 地球環境学講座 水環境・自然災害科学研究室55pthesi
Optimization of Agricultural Tire Traction on Diverse TerrainsThrough Numerical and Semi-Empirical Modeling
No full text三重大学博士(学術)application/pdfAgricultural wheeled vehicles are fundamental to modern farming, playing a critical role in enhancing productivity, reducing manual labor, and improving operational efficiency. However, their performance is highly dependent on the interaction between tires and soil,which directly influences traction, motion resistance, and soil compaction. The ability of a tire to generate sufficient traction while minimizing energy losses is crucial in optimizing agricultural machinery efficiency and reducing the negative impact on soil structure. Traction performance is governed by multiple factors, including tire tread design, terrain characteristics, and external loading conditions. A thorough understanding of these interactions is essential to developing tire designs that maximize performance across diverse agricultural terrains. This dissertation presents an in-depth numerical and semi-empirical investigation into the key parameters affecting agricultural tire traction, with a particular focus on lug design, terrain variability, and tire load effects.
The study employs Finite Element Analysis (FEA) in ANSYS to simulate tire-soil interactions and utilizes the semi-empirical Wong and Preston-Thomas tire model to analyses the traction performance. The research systematically evaluates three core traction-influencing domains: tire design, terrain characteristics, and external loading conditions. Key tire parameters such as lug angle and lug spacing are examined to determine their effects on traction force, thrust generation, and motion resistance. The study also investigates how soil properties, particularly in clay soils, influence the ability of a tire to generate traction and the extent to which terrain variability alters performance. Additionally, the impact of tire load on soil stress distribution and energy dissipation is assessed to identify optimal loading conditions for efficient traction.
To eliminate the influence of tire material properties and focus solely on tread geometry, the study utilizes a steel-based tire model. This approach ensures that the observed traction effects result purely from lug configurations and their interaction with the soil rather than from material deformation. The tire-soil contact mechanics are simulated using the Mohr-Coulomb soil material model, which accurately represents soil deformation and failure behaviors under various loading conditions. The integration of numerical results into the Wong and Preston-Thomas tire model provides a broader framework for evaluating traction performance across different terrains, ensuring that the study’s findings are applicable beyond the specific conditions modeled in the simulations.
The findings reveal that the lug angle plays a significant role in determining traction efficiency, with a 45° lug angle offering the best balance between increased thrust and reduced motion resistance. Lug spacing is also a critical factor, as intermediate spacing between 110 mm and 130 mm is found to optimize traction by maximizing thrust while preventing excessive sinkage. The study further highlights the strong influence of soil composition and moisture content on traction performance. Certain clay soil compositions present higher motion resistance and lower thrust generation, making them less favorable for efficient traction. Additionally, increasing the tire load enhances traction up to a critical threshold, beyond which excessive soil deformation and energy losses reduce overall efficiency. The research demonstrates that energy losses due to soil displacement and stress propagation beneath the tire are directly influenced by lug configurations, suggesting that well-optimized lug designs can significantly improve traction while reducing fuel consumption.
This study provides a systematic framework for designing agricultural tires optimized for specific terrains and operational requirements. The results offer practical insights for tire manufacturers, agricultural engineers, and farmers, facilitating the development of traction-enhanced tires tailored to real-world farming conditions. The research also underscores the importance of sustainable soil management in mechanized farming, as excessive traction forces can lead to increased soil compaction, which negatively impacts soil aeration, water retention, and long-term crop yields. By enhancing traction efficiency while minimizing soil degradation, optimized tire designs contribute to both economic and environmental sustainability in agriculture.
By integrating advanced FEA simulations with semi-empirical modeling, this dissertation bridges the gap between theoretical modeling and practical applications, ensuring that the findings are relevant to real-world agricultural operations. The study contributes to the field of terramechanics by offering a deeper understanding of how tire design parameters influence traction performance under varying soil conditions. Future research should focus on experimental validation of simulation results using physical tire-soil interaction testing. Additionally, extending the study to include sandy loam soils and other terrain types would provide a more comprehensive assessment of traction performance across different agricultural environments. The potential for adaptive tire designs that dynamically adjust lug spacing based on terrain variability presents another promising direction for further optimization of traction performance.
In conclusion, this dissertation presents an analysis of traction performance in agricultural tires. Through a combination of numerical modeling and semi-empirical analysis, the study identifies optimal lug configurations for improving traction efficiency, reducing motion resistance, and minimizing energy losses in clay soils. The findings contribute to advancements in agricultural tire design, providing essential guidelines for enhancing tractor mobility, fuel economy, and soil sustainability in modern farming. By optimizing tire-soil interactions, this research supports the development of more efficient and environmentally responsible agricultural machinery, ultimately promoting sustainable and productive farming practices.本文/Graduate School of Bioresources, Mie University, Tsu, Japan102pdoctoral thesi
Efficacy of minodronic acid for the prevention of osteoporosis in premenopausal women with gynaecologic disease who undergo bilateral oophorectomy: a single-centre, non-randomised controlled, experimental study
No full text三重大学博士(医学)application/pdf内容の要旨・審査結果の要旨 / 三重大学大学院医学系研究科 生命医科学専攻 臨床医学系講座 産科婦人科学分野thesi
Xa inhibitor edoxaban ameliorates hepatic ischemia-reperfusion injury via PAR-2-ERK 1/2 pathway
No full text三重大学博士(医学)application/pdfHepatic ischemia-reperfusion injury causes liver damage during surgery. In hepatic ischemia-reperfusion injury, the blood coagulation cascade is activated, causing microcirculatory incompetence and cellular injury. Coagulation factor Xa (FXa)- protease-activated receptor (PAR)-2 signaling activates inflammatory reactions and the cytoprotective effect of FXa inhibitor in several organs. However, no studies have elucidated the significance of FXa inhibition on hepatic ischemia-reperfusion injury. The present study elucidated the treatment effect of an FXa inhibitor, edoxaban, on hepatic ischemia-reperfusion injury, focusing on FXa-PAR-2 signaling. A 60 min hepatic partial-warm ischemia-reperfusion injury mouse model and a hypoxia-reoxygenation model of hepatic sinusoidal endothelial cells were used. Ischemia-reperfusion injury mice and hepatic sinusoidal endothelial cells were treated and pretreated, respectively with or without edoxaban. They were incubated during hypoxia/reoxygenation in vitro. Cell signaling was evaluated using the PAR-2 knockdown model. In ischemia-reperfusion injury mice, edoxaban treatment significantly attenuated fibrin deposition in the sinusoids and liver histological damage and resulted in both anti-inflammatory and antiapoptotic effects. Hepatic ischemia-reperfusion injury upregulated PAR-2 generation and enhanced extracellular signal-regulated kinase 1/2 (ERK 1/2) activation; however, edoxaban treatment reduced PAR-2 generation and suppressed ERK 1/2 activation in vivo. In the hypoxia/reoxygenation model of sinusoidal endothelial cells, hypoxia/reoxygenation stress increased FXa generation and induced cytotoxic effects. Edoxaban protected sinusoidal endothelial cells from hypoxia/reoxygenation stress and reduced ERK 1/2 activation. PAR-2 knockdown in the sinusoidal endothelial cells ameliorated hypoxia/reoxygenation stress-induced cytotoxicity and suppressed ERK 1/2 phosphorylation. Thus, edoxaban ameliorated hepatic ischemia-reperfusion injury in mice by protecting against micro-thrombosis in sinusoids and suppressing FXa-PAR-2-induced inflammation in the sinusoidal endothelial cells.本文 / Department of Hepatobiliary Pancreatic and Transplant Surgery, Mie University Graduate School of Medicine, Tsu, Mie, Japan19pdoctoral thesi
Temporal shape changes of pedicle screw-rod constructs after lumbar interbody fusion
Get PDF三重大学博士(医学)application/pdf内容の要旨・審査結果の要旨 / 三重大学大学院医学系研究科 生命医科学専攻 臨床医学系講座 脳神経外科学分野thesi
MAGE-A4 pMHC-targeted CAR-T cells exploiting TCR machinery exhibit significantly improved in vivo function while retaining antigen specificity
Get PDF三重大学博士(医学)application/pdfBackground: The development of chimeric antigen receptor (CAR)-T cell therapies for solid tumors has attracted considerable attention, yet their clinical efficacy remains limited. Therefore, various efforts have been made to improve the efficacy of CAR-T cell therapy. As one promising strategy, incorporating the T-cell receptor (TCR) machinery into CAR structures has been reported to improve the efficacy of CAR-T cells in studies using conventional CARs targeting such as EGFR. However, in the case of peptide/major histocompatibility complex (pMHC)-targeted CARs, the advantages of exploiting TCR machinery have not been fully elucidated. We recently developed MAGE-A4-derived pMHC (MAGE-A4 pMHC)-targeted CAR-T cells (MA-CAR-T cells) using a highly specific human scFv antibody against MAGE-A4p230-239/HLA-A*02:01. We aimed to determine whether MAGE-A4 pMHC-targeted CAR-T cells using the TCR machinery (Hybrid MA-TCR-T cells) exhibit superior functionality without compromising antigen specificity.
Methods: We constructed a retroviral vector expressing Hybrid MA-TCR where MAGE-A4 pMHC-specific scFv are fused to human TCR constant chains.
Results: Hybrid MA-TCR-T cells demonstrated superior in vitro functions compared with MA-CAR-T cells, while maintaining strict antigen specificity. In addition, functional superiority of Hybrid MA-TCR-T cells to MA-CAR-T cells became more pronounced on repetitive antigen stimulation. In particular, Hybrid MA-TCR-T cells significantly inhibited tumor growth in an immunodeficient mouse model more effectively than MA-CAR-T cells. Ex vivo analyses indicated that their enhanced therapeutic efficacy might result from higher infiltration of functionally active, less differentiated Hybrid MA-TCR-T cells in tumor tissues.
Conclusions: These findings suggest that leveraging the TCR machinery is a promising strategy for enhancing pMHC-targeted CAR-T cell therapy for solid tumors, potentially leading to more effective treatments.本文 / Personalized Cancer Immunotherapy, Mie University Graduate School of Medicine, Tsu, Japan19pdoctoral thesi
Release of Exosomal PD-Ll in Bone and Soft Tissue Sarcomas and Its Relationship to Radiotherapy
Get PDF三重大学博士(医学)application/pdf(1) Background: Exosomal PD-L1 has garnered attention owing to its role in instigating systemic immune suppression. The objective of this study is to elucidate whether bone and soft tissue sarcoma cells possess the capacity to secrete functionally active exosomal PD-L1 and whether radiotherapy (RT) induces the exosomal PD-L1 release. (2) Methods: Human osteosarcoma cell line 143B and human fibrosarcoma cell line HT1080 were utilized. Exosomes were isolated from the culture medium and blood via ultracentrifugation. The expression of PD-L1 on both tumor cells and exosomes was evaluated. The inhibitory effect on PBMC was employed to assess the activity of exosomal PD-L1. Post radiotherapy, changes in PD-L1 expression were compared. (3) Results: Exosomal PD-L1 was detected in the culture medium of tumor cells but was absent in the culture medium of PD-L1 knockout cells. Exosomal PD-L1 exhibited an inhibitory effect on PBMC activation. In tumor-bearing mice, human-derived exosomal PD-L1 was detected in the bloodstream. Following radiotherapy, tumor cells upregulated PD-L1, and human-derived exosomal PD-L1 were detected in the bloodstream. (4) Conclusions: Exosomal PD-L1 emanates from bone and soft tissue sarcoma cells and is disseminated into the circulatory system. The levels of PD-L1 in tumor cells and the release of exosomal PD-L1 were augmented after irradiation with RT.本文 / Department of Orthopaedic Surgery, Mie University Graduate School of Medicine, Tsu 514-8507, Mie, Japan14pdoctoral thesi
2-4 年目の看護師を対象としたオンライン緩和ケア教育プログラムの開発とその評価
Get PDF三重大学博士(看護学)application/pdf要約 / 三重大学大学院医学系研究科 看護学専攻（博士後期課程）看護学領域 成熟期看護学分野thesi
