ANALYSIS OF DYNAMIC INTERACTION BETWEEN FLEXIBLE BODY OF OVERHEAD CONTACT WIRE AND ACTIVE CONTROL PANTOGRAPH CONSIDERING VERTICAL BODY VIBRATION

The current collection system consists of a pantograph placed on the roof top of a trains’ vehicle and overhead contact wire supported by evenly spaced vertical holders which supply the current to the pantograph from the electric power grid. Most of the pantographs produce averagely good performances at low and medium speeds, approximately less than 250 km/h. However, at higher speeds, the response of the pantographs is distorted. Thus the stability of the current collection is in peril. In addition, due to vertical vibration of the car body during high speed, contact force variation occurs between the pantograph and overhead wire. Therefore, it is necessary to maintain the contact between pantograph and overhead wire. In this study, the multi-body dynamics analysis is used to model the flexible body of overhead wire. An excitation experiment is performed in order to determine the parameters of pantograph. With consideration of vertical body vibration, an active pantograph control is developed to eliminate the effect of vibration to contact force, reduce the maximum peaks and avoid contact loss

ACTIVE CONTROL OF HIGH-SPEED RAILWAY VEHICLE PANTOGRAPH CONSIDERING VERTICAL BODY VIBRATION

The current collection system consists of a pantograph placed on the roof top of a trains’ vehicle and overhead contact wire supported by evenly spaced vertical holders which supply the current to the pantograph from the electric power grid. Most of the pantographs produce averagely good performances at low and medium speeds, approximately less than 250 km/h. However, at higher speeds, the response of the pantographs is distorted. Thus the stability of the current collection is in peril. In addition, due to vertical vibration of the car body during high speed, contact force variation occurs between the pantograph and overhead wire. Therefore, it is necessary to maintain the contact between pantograph and overhead wire. In this study, the multi-body dynamics analysis is used to model the flexible body of overhead wire. An excitation experiment is performed in order to determine the parameters of pantograph. With consideration of vertical body vibration, an active pantograph control is developed to eliminate the effect of vibration to contact force, reduce the maximum peaks and avoid contact loss

SWING-UP CONTROL OF MASS BODY INTERLINKED FLEXIBLE TETHER

One of the applications of tether system is in the field of satellite technology, where the mother ship and satellite equipment are connected with a cable. In order to grasp the motion of this kind of tether system in detail, the tether can be effectively modeled as flexible body and dealt by multibody dynamic analysis. In the analysis and modeling of flexible body of tether, large deformation and large displacement must be considered. Multibody dynamic analysis such as Absolute Nodal Coordinate Formulation with an introduction of the effect of damping force formulation can be used to describe the motion behavior of a flexible body. In this study, a parameter identification technique via an experimental approach is proposed in order to verify the modeling method. An example of swing-up control using the genetic algorithm control approach is performed through simulation and experiment. The validity of the model and availability of motion control based on multibody dynamics analysis are shown by comparison between numerical simulation and experiment

Analysis Of Dynamic Interaction Between Flexible Body Of Overhead Contact Wire And Active Control Pantograph Considering Vertical Body Vibration

The current collection system consists of a pantograph placed on the roof top of a trains' vehicle and overhead contact wire supported by evenly spaced vertical holders which supply the current to the pantograph from the electric power grid. Most of the pantographs produce averagely good performances at low and medium speeds, approximately less than 250 km/h. However, at higher speeds, the response of the pantographs is distorted. Thus the stability of the current collection is in peril. In addition, due to vertical vibration of the car body during high speed, contact force variation occurs between the pantograph and overhead wire. Therefore, it is necessary to maintain the contact between pantograph and overhead wire. In this study, the multi-body dynamics analysis is used to model the flexible body of overhead wire. An excitation experiment is performed in order to determine the parameters of pantograph. With consideration of vertical body vibration, an active pantograph control is developed to eliminate the effect of vibration to contact force, reduce the maximum peaks and avoid contact loss

Successful esophageal bypass surgery in a patient with a large tracheoesophageal fistula following endotracheal stenting and chemoradiotherapy for advanced esophageal cancer: case report

A 63-year-old man with esophageal achalasia for more than 20 years complained of respiratory distress. He was admitted as an emergency to the referral hospital three months previously. Computed tomography revealed tracheobronchial stenosis due to advanced esophageal cancer with tracheal invasion. He underwent tracheobronchial stenting and chemoradiotherapy. A large tracheoesophageal fistula (TEF) developed after irradiation (18 Gy) and chemotherapy, and he was unable to eat. Thereafter, he was referred to our hospital, where we performed esophageal bypass surgery using a gastric conduit. A percutaneous cardiopulmonary support system was prepared due to the risk of airway obstruction during anesthesia. A small-diameter tracheal tube inserted into the stent achieved ordinary respiratory management. No anesthesia-related problems were encountered. Oral intake commenced on postoperative day 9. He was discharged on postoperative day 23 and was able to take in sustenance orally right up to the last moment of his life. Esophageal bypass under general anesthesia can be performed in patients with large TEF with sufficient preparation for anesthetic management

Photoinduced swing of a diarylethene thin broad sword shaped crystal:a study on the detailed mechanism

We report a swinging motion of photochromic thin broad sword shaped crystals upon continuous irradiation with UV light. By contrast in thick crystals, photosalient phenomena were observed. The bending and swinging mechanisms are in fact due to molecular size changes as well as phase transitions. The first slight bending away from the light source is due to photocyclization-induced surface expansion, and the second dramatic bending toward UV incidence is due to single-crystal-to-single-crystal (SCSC) phase transition from the original phase I to phase IIUV. Upon visible light irradiation, the crystal returned to phase I. A similar SCSC phase transition with a similar volume decrease occurred by lowering the temperature (phase IIItemp). For both photoinduced and thermal SCSC phase transitions, the symmetry of the unit cell is lowered; in phase IIUV the twisting angle of disordered phenyl groups is different between two adjacent molecules, while in phase IIItemp, the population of the phenyl rotamer is different between adjacent molecules. In the case of phase IIUV, we found thickness dependent photosalient phenomena. The thin broad sword shaped crystals with a 3 mu m thickness showed no photosalient phenomena, whereas photoinduced SCSC phase transition occurred. In contrast, large crystals of several tens of mu m thickness showed photosalient phenomena on the irradiated surface where SCSC phase transition occurred. The results indicated that the accumulated strain, between isomerized and non-isomerized layers, gave rise to the photosalient phenomenon

Acetylation Unleashes Protein Demons of Dementia

Aberrant posttranslational modifications of proteins can impair synaptic plasticity and may render neurons vulnerable to degeneration during aging. In this issue of Neuron, Min et al. show that acetylation of the amino acid lysine in the microtubule-associated protein tau prevents its ubiquitin-mediated degradation, resulting in “tau tangles” similar to those of dementias. Other recent studies suggest that lysine hyperacetylation contributes to the accumulation of amyloid β-peptide in Alzheimer's disease and to impaired cognitive function resulting from a trophic factor deficit

FXYD3 functionally demarcates an ancestral breast cancer stem cell subpopulation with features of drug-tolerant persisters

乳がんの再発を起こす原因細胞を解明. 京都大学プレスリリース. 2023-11-16.The heterogeneity of cancer stem cells (CSCs) within tumors presents a challenge in therapeutic targeting. To decipher the cellular plasticity that fuels phenotypic heterogeneity, we undertook single-cell transcriptomics analysis in triple-negative breast cancer (TNBC) to identify subpopulations in CSCs. We found a subpopulation of CSCs with ancestral features that is marked by FXYD domain–containing ion transport regulator 3 (FXYD3), a component of the Na⁺/K⁺ pump. Accordingly, FXYD3⁺ CSCs evolve and proliferate, while displaying traits of alveolar progenitors that are normally induced during pregnancy. Clinically, FXYD3⁺ CSCs were persistent during neoadjuvant chemotherapy, hence linking them to drug-tolerant persisters (DTPs) and identifying them as crucial therapeutic targets. Importantly, FXYD3⁺ CSCs were sensitive to senolytic Na⁺/K⁺ pump inhibitors, such as cardiac glycosides. Together, our data indicate that FXYD3⁺ CSCs with ancestral features are drivers of plasticity and chemoresistance in TNBC. Targeting the Na⁺/K⁺ pump could be an effective strategy to eliminate CSCs with ancestral and DTP features that could improve TNBC prognosis

Development of a Multi-Step Leukemogenesis Model of MLL-Rearranged Leukemia Using Humanized Mice

Mixed-lineage-leukemia (MLL) fusion oncogenes are intimately involved in acute leukemia and secondary therapy-related acute leukemia. To understand MLL-rearranged leukemia, several murine models for this disease have been established. However, the mouse leukemia derived from mouse hematopoietic stem cells (HSCs) may not be fully comparable with human leukemia. Here we developed a humanized mouse model for human leukemia by transplanting human cord blood-derived HSCs transduced with an MLL-AF10 oncogene into a supra-immunodeficient mouse strain, NOD/Shi-scid, IL-2Rγ−/− (NOG) mice. Injection of the MLL-AF10-transduced HSCs into the liver of NOG mice enhanced multilineage hematopoiesis, but did not induce leukemia. Because active mutations in ras genes are often found in MLL-related leukemia, we next transduced the gene for a constitutively active form of K-ras along with the MLL-AF10 oncogene. Eight weeks after transplantation, all the recipient mice had developed acute monoblastic leukemia (the M5 phenotype in French-American-British classification). We thus successfully established a human MLL-rearranged leukemia that was derived in vivo from human HSCs. In addition, since the enforced expression of the mutant K-ras alone was insufficient to induce leukemia, the present model may also be a useful experimental platform for the multi-step leukemogenesis model of human leukemia