130 results on '"Kengo Yoshida"'
Search Results
2. Spectra and characteristics of somatic mutations induced by ionizing radiation in hematopoietic stem cells
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Yukiko Matsuda, Arikuni Uchimura, Yasunari Satoh, Naohiro Kato, Masaaki Toshishige, Junko Kajimura, Kanya Hamasaki, Kengo Yoshida, Tomonori Hayashi, Asao Noda, and Osamu Tanabe
- Subjects
Multidisciplinary - Abstract
Spectra and frequencies of spontaneous and X-ray-induced somatic mutations were revealed with mouse long-term hematopoietic stem cells (LT-HSCs) by whole-genome sequencing of clonal cell populations propagated in vitro from single isolated LT-HSCs. SNVs and small indels were the most common types of somatic mutations, and increased up to twofold to threefold by whole-body X-irradiation. Base substitution patterns in the SNVs suggested a role of reactive oxygen species in radiation mutagenesis, and signature analysis of single base substitutions (SBS) revealed a dose-dependent increase of SBS40. Most of spontaneous small deletions were shrinkage of tandem repeats, and X-irradiation specifically induced small deletions out of tandem repeats (non-repeat deletions). Presence of microhomology sequences in non-repeat deletions suggested involvement of microhomology mediated end-joining repair mechanisms as well as nonhomologous end-joining in radiation-induced DNA damages. We also identified multisite mutations and structural variants (SV), i.e., large indels, inversions, reciprocal translocations, and complex variants. The radiation-specificity of each mutation type was evaluated from the spontaneous mutation rate and the per-Gy mutation rate estimated by linear regression, and was highest with non-repeat deletions without microhomology, followed by those with microhomology, SV except retroelement insertions, and multisite mutations; these types were thus revealed as mutational signatures of ionizing radiation. Further analysis of somatic mutations in multiple LT-HSCs indicated that large fractions of postirradiation LT-HSCs originated from single LT-HSCs that survived the irradiation and then expanded in vivo to confer marked clonality to the entire hematopoietic system, with varying clonal expansion and dynamics depending on radiation dose and fractionation.
- Published
- 2023
3. Adjustment of crystal orientations and application to crystal plasticity simulation of cup drawing
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Kengo Yoshida, Tomohisa Honke, Yasuhito Yamazaki, Kunio Hayakawa, and Hidetaka Nakanishi
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General Materials Science - Published
- 2022
4. Measurement of work hardening behavior of 5052 aluminum alloy sheet subjected to cross loadings
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Shinya Atsumi and Kengo Yoshida
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Mechanics of Materials ,Mechanical Engineering ,Materials Chemistry ,Metals and Alloys - Published
- 2021
5. Measurement and crystal plasticity simulation of plastic deformation behavior of 5052 aluminum alloy sheet subjected to various loading modes
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Kengo Yoshida, Shinya Atsumi, and Tomofumi Tsuji
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Materials science ,Mechanics of Materials ,Mechanical Engineering ,Alloy ,Materials Chemistry ,Metals and Alloys ,5052 aluminium alloy ,engineering ,engineering.material ,Composite material ,Crystal plasticity - Published
- 2021
6. Massive expansion of multiple clones in the mouse hematopoietic system long after whole-body X-irradiation
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Kengo Yoshida, Yasunari Satoh, Arikuni Uchimura, Munechika Misumi, Seishi Kyoizumi, Masataka Taga, Yukiko Matsuda, Asao Noda, and Yoichiro Kusunoki
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Mice ,Multidisciplinary ,Bone Marrow ,Animals ,Bone Marrow Cells ,Hematopoietic Stem Cells ,Whole-Body Irradiation ,Clone Cells ,Hematopoiesis - Abstract
Clonal hematopoiesis (CH) is prevalent in the elderly and associates with hematologic malignancy and cardiovascular disease. Although the risk of developing these diseases increases with radiation doses in atomic-bomb survivors, the causal relationship between radiation exposure and CH is unclear. This study investigated whether radiation exposure induces CH in mice 12–18 months after 3-Gy whole-body irradiation. We found radiation-associated increases in peripheral blood myeloid cells and red blood cell distribution width (RDW). Deep sequencing of bone marrow and non-hematopoietic tissue cells revealed recurrent somatic mutations specifically in the hematopoietic system in 11 of 12 irradiated mice but none in 6 non-irradiated mice. The irradiated mice possessed mutations with variant allele frequencies (VAFs) of > 0.02 on an average of 5.8 per mouse; mutations with VAFs of > 0.1 and/or deletion were prevalent. Examining hematopoietic stem/progenitor cells in two irradiated mice revealed several mutations co-existing in the same clones and multiple independent clones that deliver 60–80% of bone marrow nuclear cells. Our results indicate development of massive CH due to radiation exposure. Moreover, we have characterized mutations in radiation-induced CH.
- Published
- 2022
7. Real‐world safety of the novel, free radical scavenger edaravone for amyotrophic lateral sclerosis patients: Data from the post‐marketing surveillance SUNRISE Japan
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Kengo Yoshida, Gen Sobue, Yutaka Kawaguchi, Satoshi Yuki, Kaoru Ishizaki, Masao Matsuda, and Kenta Yoshimura
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Oncology ,medicine.medical_specialty ,business.industry ,Postmarketing surveillance ,Free radical scavenger ,medicine.disease ,chemistry.chemical_compound ,Neurology ,chemistry ,Internal medicine ,medicine ,Edaravone ,Neurology (clinical) ,Amyotrophic lateral sclerosis ,business - Published
- 2021
8. Study of Structure for Transverse Flux Type Flux Reversal Linear Motor
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Shin Matsuzawa, Kengo Yoshida, and Kenji Suzuki
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Transverse flux ,Physics ,Structure (category theory) ,Mechanics ,Type (model theory) ,Linear motor ,Flux (metabolism) - Published
- 2021
9. Longitudinal changes in red blood cell distribution width decades after radiation exposure in atomic‐bomb survivors
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Yoichiro Kusunoki, Munechika Misumi, Michiko Yamada, and Kengo Yoshida
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Erythrocyte Indices ,Male ,Erythrocytes ,Short Report ,Physiology ,Radiation Dosage ,03 medical and health sciences ,0302 clinical medicine ,Sex Factors ,Short Reports ,Risk Factors ,Medicine ,Humans ,Longitudinal Studies ,Mortality ,Aged ,Prior Radiation ,business.industry ,Radiation dose ,Smoking ,Red blood cell distribution width ,Hematology ,Radiation Exposure ,Atomic Bomb Survivors ,Radiation exposure ,Haematopoiesis ,030220 oncology & carcinogenesis ,Regression Analysis ,Female ,Morbidity ,business ,030215 immunology - Abstract
Summary Red blood cell distribution width (RDW), which generally increases with age, is a risk marker for morbidity and mortality in various diseases. We investigated the association between elevated RDW and prior radiation exposure by examining longitudinal RDW changes in 4204 atomic‐bomb survivors over 15 years. A positive association was found between RDW and radiation dose, wherein RDW increased by 0·18%/Gy. This radiation‐associated effect increased as the participants aged. Elevated RDW was also associated with higher all‐cause mortality. The biological mechanisms underlying these observed associations merit further investigation.
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- 2020
10. Forming limit diagram of aluminum alloy sheets
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Kengo Yoshida
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Materials science ,Forming limit diagram ,chemistry ,Mechanics of Materials ,Aluminium ,Mechanical Engineering ,Metallurgy ,Alloy ,Materials Chemistry ,Metals and Alloys ,engineering ,chemistry.chemical_element ,engineering.material - Published
- 2020
11. An implicit formulation of a two-grain cluster type homogenization approach for polycrystals
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Kengo Yoshida
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Mechanics of Materials ,Mechanical Engineering ,General Materials Science - Published
- 2022
12. Effects of Prohydrojasmon on the Number of Infesting Herbivores and Biomass of Field-Grown Japanese Radish Plants
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Kinuyo Yoneya, Junji Takabayashi, Kengo Yoshida, Masayoshi Uefune, Rika Ozawa, Yuka Okemoto, and Hiroshi Abe
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prohydrojasmon ,media_common.quotation_subject ,Insect ,Raphanus sativus L. var. hortensis Backer ,Plant Science ,Parasitoid ,SB1-1110 ,thrips ,chemistry.chemical_compound ,media_common ,Original Research ,Herbivore ,biology ,business.industry ,Jasmonic acid ,fungi ,Pest control ,Plant culture ,food and beverages ,biology.organism_classification ,parasitoids ,Terpenoid ,aphids ,Horticulture ,leaf-mining fly larvae ,chemistry ,lepidopteran larvae ,vegetable weevils ,business ,Methyl salicylate ,Salicylic acid - Abstract
Prohydrojasmon (PDJ), an analog of jasmonic acid (JA), was found to induce direct and indirect defenses against herbivores in non-infested plants. To test whether PDJ can be used for pest control in crop production, we conducted experiments in pesticide-free Japanese radish fields from October 4 to December 12 in 2015. Twenty-four Japanese radish plants in three plots were treated with a 100 times-diluted commercial formulation (5%) of PDJ (treated plants), and 24 plants in three different plots were treated with water (control plants) until November 29 every week. Throughout the observation period, the number of aphids, leaf-mining fly larvae, vegetable weevils, and thrips was significantly lower on the treated plants than on the control plants. In contrast, the number of lepidopteran larvae was not significantly different between the treated and control plants throughout the study period. Parasitized aphids (mummies) were also observed in both plots. Poisson regression analyses showed that a significantly higher number of mummies was recorded on the treated plants as compared to that on the control plants when the number of aphids increased. This suggested that PDJ application to Japanese radish plants attracted more parasitoid wasps on the treated plants than on the control plants. We also identified eight terpenoids and methyl salicylate as the PDJ-induced plant volatiles in the headspace of the treated plants. Some of these volatiles might be responsible for attracting aphid-parasitoid wasps in the field. However, for other insect pests, we did not find any natural enemies. Interestingly, the genes of the JA and salicylic acid signaling pathways were differentially upregulated in the treated plants. We also observed that the PDJ treatments induced the expression of the genes related to glucosinolate biosynthesis and the subsequent isothiocyanate formation. Additionally, the weights of both the aboveground and belowground parts of the treated plants were significantly lower than those of the respective parts of the control plants. These results indicated that the treatment of Japanese radish plants with a 100 times-diluted commercial formulation of PDJ induced their direct and indirect defenses against several insect pest species to reduce their numbers, and negatively affected their biomass.
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- 2021
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13. An alternative formulation of two-grain cluster model for homogenization of elastoviscoplastic behavior of polycrystal
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Kengo Yoshida
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Mechanics of Materials ,Mechanical Engineering ,General Materials Science - Published
- 2022
14. Smart Preparation of Polydiacetylene Hydrogel Based on Self-Assembly of Tricosadiynoic Acid and 1-Oleoylglycerol (Monoolein)
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Yoko Otsuka, Kengo Yoshida, Hiroshi Umakoshi, and Keishi Suga
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symbols.namesake ,Materials science ,General Chemical Engineering ,symbols ,Nanotechnology ,General Chemistry ,Self-assembly ,Raman spectroscopy - Published
- 2019
15. Radiation exposure and longitudinal changes in peripheral monocytes over 50 years: the Adult Health Study of atomic‐bomb survivors
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Ayumi Hida, Benjamin French, Waka Ohishi, Yoichiro Kusunoki, Kengo Yoshida, and Noriaki Yoshida
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Adult ,Male ,Longitudinal study ,Lymphocyte ,Cell ,Inflammation ,Monocytes ,Leukocyte Count ,03 medical and health sciences ,0302 clinical medicine ,Japan ,Humans ,Medicine ,Longitudinal Studies ,Mortality ,Radiation Injuries ,Proportional Hazards Models ,Retrospective Studies ,Nuclear Weapons ,business.industry ,Monocyte ,Age Factors ,Dose-Response Relationship, Radiation ,Hematology ,Middle Aged ,Radiation Exposure ,Atomic Bomb Survivors ,Hematopoiesis ,Peripheral ,Haematopoiesis ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,Immunology ,Regression Analysis ,Female ,Stem cell ,medicine.symptom ,business ,Follow-Up Studies ,030215 immunology - Abstract
Enhanced inflammatory responses have been suggested decades after radiation exposure in atomic-bomb survivors, but cellular and molecular alterations related to prolonged inflammation remain unclear. This study, utilizing longitudinal haematological data over 50 years for 14 000 persons, investigated whether radiation exposure promoted the relative increase in peripheral myeloid cells, known as an aging-associated indicator of low-grade inflammation. Statistical modelling was performed with a linear mixed-effects model for leucocyte subsets, together with a proportional hazards regression model for all-cause mortality. We found that age trends in lymphocyte, neutrophil and monocyte percentages or counts differed before versus after age 60 years. Radiation dose was associated with monocyte percentages and counts, but not with the lymphoid-myeloid cell ratio. Radiation effects on monocytes were stronger after versus before age 60 years. Increases in monocyte percentages and counts were associated with higher risk of all-cause mortality. Studies of chromosomal aberrations have shown a clonal expansion of haematopoietic stem cells among atomic-bomb survivors. Therefore, radiation exposure might accelerate aging-associated clonal haematopoiesis, which could result in a long-lasting elevation of circulating monocytes.
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- 2019
16. Intracellular reactive oxygen species level in blood cells of atomic bomb survivors is increased due to aging and radiation exposure
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Tomonori Hayashi, Waka Ohishi, Yukari Morishita, Kyoji Furukawa, Seishi Kyoizumi, Naohiro Kato, Yoichiro Kusunoki, Ikue Hayashi, and Kengo Yoshida
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0301 basic medicine ,medicine.medical_specialty ,Aging ,T cell ,CD8-Positive T-Lymphocytes ,medicine.disease_cause ,Biochemistry ,Blood cell ,03 medical and health sciences ,0302 clinical medicine ,Immune system ,Physiology (medical) ,Internal medicine ,medicine ,Humans ,Survivors ,Nuclear Warfare ,biology ,medicine.diagnostic_test ,Chemistry ,Dose-Response Relationship, Radiation ,Hydrogen Peroxide ,Radiation Exposure ,Atomic Bomb Survivors ,Ferritin ,030104 developmental biology ,Endocrinology ,medicine.anatomical_structure ,biology.protein ,Serum iron ,Reactive Oxygen Species ,030217 neurology & neurosurgery ,Intracellular ,Oxidative stress ,CD8 - Abstract
Although reactive oxygen species (ROS) play important roles in immune responses, excessive ROS production and accumulation might enhance the risk of inflammation-related diseases. Moreover, impaired immune function and the acceleration of pre-clinically persistent inflammation due to aging and radiation exposure have been observed in atomic bomb (A-bomb) survivors more than 60 years post-exposure. Meanwhile, the effects of aging and radiation exposure on ROS production in immune cells have not been characterized. This study investigated the relationship between intracellular ROS (H2O2 and O2•-) levels in blood cells or T cell subsets and serum iron, ferritin, and C-reactive protein (CRP) levels, as well as how these variables are affected by age and radiation exposure in A-bomb survivors. We examined 2495 Hiroshima A-bomb survivors. Multiple linear regression models adjusted for confounding factors indicated that intracellular O2•- levels in monocytes, granulocytes, and lymphocytes, and particularly in memory CD8+ T cells, including effector memory and terminally differentiated effector memory CD8+ T cells, increased with radiation dose. Additionally, serum iron, ferritin, and CRP levels affected intracellular ROS levels in specific blood cell types and T cell subsets. Serum CRP levels increased significantly with increasing age and radiation dose. Finally, when divided into three groups according to serum CRP levels, dose-dependent increases in the intracellular O2•- levels in blood cells and central memory and effector memory CD8+ T cells were most prominently observed in the high-CRP group. These results suggest that an increase in the levels of certain intracellular ROS, particularly after radiation exposure, might be linked to enhanced inflammatory status, including elevated serum CRP levels and reduced serum iron levels. This study reveals that aging and radiation exposure increase oxidative stress in blood cells, which is involved in impaired immune function and accelerated pre-clinically persistent inflammation in radiation-exposed individuals.
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- 2021
17. Impact of early life exposure to ionizing radiation on influenza vaccine response in an elderly Japanese cohort
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Kei Nakachi, Hiroko Nagamura, Keiko Furudoi, Donna M. Murasko, Yiqun Hu, Munechika Misumi, Ivo D. Shterev, Janko Nikolich-Žugich, Keiko Sasaki, Yukari Morishita, Mayumi Maki, Kengo Yoshida, Susan Geyer, Tomonori Hayashi, Yoichiro Kusunoki, Laura P. Hale, Heather E. Lynch, Saeko Fujiwara, Gregory D. Sempowski, Seishi Kyoizumi, Waka Ohishi, and Ikue Hayashi
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Male ,0301 basic medicine ,Influenza vaccine ,Antibodies, Viral ,Peripheral blood mononuclear cell ,Article ,03 medical and health sciences ,Influenza A Virus, H1N1 Subtype ,Sex Factors ,0302 clinical medicine ,Antigen ,Radiation, Ionizing ,Influenza, Human ,Humans ,Medicine ,Aged ,Aged, 80 and over ,Hemagglutination assay ,General Veterinary ,General Immunology and Microbiology ,biology ,business.industry ,Public Health, Environmental and Occupational Health ,Antibody titer ,Hemagglutination Inhibition Tests ,humanities ,Vaccination ,030104 developmental biology ,Infectious Diseases ,Influenza Vaccines ,030220 oncology & carcinogenesis ,Cohort ,Immunology ,biology.protein ,Cytokines ,Molecular Medicine ,Female ,Chemokines ,Antibody ,business - Abstract
The objective of this study was to evaluate effects of whole body radiation exposure early in life on influenza vaccination immune responses much later in life. A total of 292 volunteers recruited from the cohort members of ongoing Adult Health Study (AHS) of Japanese atomic bomb (A-bomb) survivors completed this observational study spanning two influenza seasons (2011-2012 and 2012-2013). Peripheral blood samples were collected prior to and three weeks after vaccination. Serum hemagglutination inhibition (HAI) antibody titers were measured as well as concentrations of 25 cytokines and chemokines in culture supernatant from peripheral blood mononuclear cells, with and without in vitro stimulation with influenza vaccine. We found that influenza vaccination modestly enhanced serum HAI titers in this unique cohort of elderly subjects, with seroprotection ranging from 18 to 48% for specific antigen/season combinations. Twelve percent of subjects were seroprotected against all three vaccine antigens post-vaccination. Males were generally more likely to be seroprotected for one or more antigens post-vaccination, with no differences in vaccine responses based on age at vaccination or radiation exposure in early life. These results show that early life exposure to ionizing radiation does not prevent responses of elderly A-bomb survivors to seasonal influenza vaccine.
- Published
- 2018
18. Plastic flow of thin-walled tubes under nonlinear tension-torsion loading paths and an improved pseudo-corner model
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Kengo Yoshida and Takuma Tsuchimoto
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Materials science ,Mechanical Engineering ,Uniaxial tension ,Torsion (mechanics) ,chemistry.chemical_element ,Thin walled ,02 engineering and technology ,Strain rate ,Plasticity ,021001 nanoscience & nanotechnology ,Nonlinear system ,020303 mechanical engineering & transports ,0203 mechanical engineering ,chemistry ,Mechanics of Materials ,Aluminium ,General Materials Science ,Composite material ,Deformation (engineering) ,0210 nano-technology - Abstract
The elastoplastic deformation behaviors of thin-walled tubes made of pure aluminum and steel were measured under various tension–torsion combined loadings. The ratio between the displacement and rotation of a grip was held constant for the linear-loading experiment. In the nonlinear-loading experiments, a specimen was subjected to uniaxial tension followed by the simultaneous application of tension and torsion. It was determined that the associated flow rule predicts the plastic flow behaviors observed in the experiments with sufficient accuracy, provided that the specimen was subjected to linear loadings. Meanwhile, under nonlinear loadings, the plastic flow behaviors were markedly dissimilar to those in the linear loadings, and the direction of plastic flow rotated toward the direction of the stress/strain rate. By analyzing the experimental results, a linear relationship between the plastic flow direction and strain rate direction was determined. Therefore, the experimental data demonstrated that the stress state and the strain rate direction are essential parameters characterizing a plastic flow rule. Eventually, a pseudo-corner model capable of reproducing experimentally observed plastic deformation behavior was proposed.
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- 2018
19. Elastoplastic Deformation of a Steel Tube Subjected to the Strain Paths Composed of Two Line Segments
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Takuma Tsuchimoto and Kengo Yoshida
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Materials science ,Strain (chemistry) ,business.industry ,Metals and Alloys ,02 engineering and technology ,Structural engineering ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,020303 mechanical engineering & transports ,Line segment ,0203 mechanical engineering ,Materials Chemistry ,Steel tube ,Physical and Theoretical Chemistry ,Deformation (engineering) ,Composite material ,0210 nano-technology ,business - Published
- 2018
20. Experiments and Crystal Plasticity Simulations on Plastic Anisotropy of Naturally Aged and Annealed Al–Mg–Si Alloy Sheets
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Kengo Yoshida, Yasuhito Yamazaki, and Hidetaka Nakanishi
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crystal plasticity ,Mining engineering. Metallurgy ,TN1-997 ,Al–Mg–Si alloy sheet ,dislocation interaction matrix ,anisotropy ,Metals and Alloys ,General Materials Science - Abstract
The influence of the heat treatment on the plastic anisotropy of an Al–Mg–Si sheet was investigated by experiments and crystal plasticity simulations. Uniaxial tension tests were conducted for the naturally aged (T4 temper) and annealed (O temper) Al–Mg–Si sheets. Solute atoms Mg and Si form clusters in the T4 temper sheet, while they bind to form precipitates in the O temper sheet. It is found that the in-plane variation of the R value, texture, and grain size are almost identical for both sheets. By contrast, the anisotropy of the flow stress is clearly dissimilar; the flow stress is the highest in the diagonal direction for the O temper sheet, whereas the flow stress in that direction is nearly lowest for the T4 temper sheet. Thus, the heat treatment alters the anisotropy of the flow stress. The plastic behaviors of the specimens were simulated using the dislocation density-based crystal plasticity model. The influence of the dislocation interaction matrix on the plastic anisotropy was examined. The orientation dependence of the flow stress is found to be sensitive to the interaction matrix. The flow stresses predicted by the interaction matrix determined based on the dislocation dynamic simulation agree with the experimental results for the O temper sheet. Whereas this interaction matrix does not reproduce the flow stress anisotropy for the T4 temper sheet. When the interactions among the dislocations are set to equivalent—i.e., the interaction matrix is filled with unity—the crystal plasticity simulation results in the flow stress anisotropy that is similar to the experimental trend of the T4 temper sheet. In contrast to the flow stress, the R value is insensitive to the interaction matrix, and the predicted R values agree with the experimental results for both specimens.
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- 2021
21. A plastic flow rule representing corner effects predicted by rate-independent crystal plasticity
- Author
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Kengo Yoshida
- Subjects
Materials science ,business.industry ,Applied Mathematics ,Mechanical Engineering ,02 engineering and technology ,Structural engineering ,Mechanics ,Plasticity ,Strain rate ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Physics::Fluid Dynamics ,Shear modulus ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Mechanics of Materials ,Plastic bending ,Modeling and Simulation ,Pure bending ,General Materials Science ,Levy–Mises equations ,0210 nano-technology ,business ,Shear band ,Plane stress - Abstract
Elastoplastic responses of rate-independent polycrystals are simulated under linear and various nonlinear strain paths, and the influence of the loading condition on the plastic flow behavior is investigated. It is observed that the shear components of elastoplastic tangent moduli start decreasing when the plastic deformation occurs, and the direction of the plastic flow depends on the direction of the stress/strain rates. A phenomenological plastic flow rule capable of reproducing these behaviors is developed. The flow rule relates the direction of plastic strain rate to the direction of strain rate, and yields the reduction of shear modulus after plastic yielding. The proposed constitutive model is then integrated into a finite element program, and the plane strain tension and pure bending are analyzed. The advantage of the proposed flow rule for simulating the occurrence of a shear band is demonstrated.
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- 2017
22. Safety verification method for preventing friction blisters during utilization of physical assistant robots
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Yasuhiro Akiyama, Xuewei Mao, Shogo Okamoto, Yoji Yamada, and Kengo Yoshida
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musculoskeletal diseases ,0209 industrial biotechnology ,Engineering ,Friction force ,Mechanical engineering ,02 engineering and technology ,030207 dermatology & venereal diseases ,03 medical and health sciences ,020901 industrial engineering & automation ,0302 clinical medicine ,medicine ,Assistive robotics ,integumentary system ,business.industry ,Blisters ,musculoskeletal system ,Computer Science Applications ,body regions ,Human-Computer Interaction ,Hardware and Architecture ,Control and Systems Engineering ,Robot ,medicine.symptom ,business ,human activities ,Software - Abstract
This study is mainly concerned with the potential hazards of interactive friction force on a human–robot contact surface, which may result in various skin traumas, such as friction blisters. In thi...
- Published
- 2017
23. General synthesis, structure, and optical properties of benzothiophene-fused benzoheteroles containing Group 15 and 16 elements
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Kurihara Rina, Misae Kanai, Naoki Kakusawa, Shuji Yasuike, Atsuya Muranaka, Mio Matsumura, Kengo Yoshida, Masanobu Uchiyama, and Daisuke Hashizume
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010405 organic chemistry ,Chemistry ,Organic Chemistry ,Structure (category theory) ,Benzothiophene ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,chemistry.chemical_compound ,Crystallography ,Atomic radius ,Planar ,Computational chemistry ,Group (periodic table) ,Drug Discovery ,Density functional theory ,Excitation - Abstract
A series of benzothieno[3,2-b]benzoheteroles containing Group 15 (N, P, As, and Sb) and Group 16 (O, S, Se, and Te) elements were synthesized by a versatile method. X-ray analyses revealed that all the tetracyclic heteroacene skeletons were planar. A linear relationship was found between the excitation energies of Group 16-heteroacenes and their atomic radius, in contrast to Group 15-heteroacenes. Density functional theory calculations and electrochemical measurements were performed to understand the structure–optical property relationship.
- Published
- 2016
24. Proposal of a Novel Transfer Device Using a Linear Motor in Parallel Synchronous Operation
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Kengo Yoshida, Hideo Dohmeki, and Kenji Suzuki
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Transverse plane ,Dimension (vector space) ,Computer science ,Electromagnetic coil ,Transfer (computing) ,Electronic engineering ,Graph (abstract data type) ,Linear motor ,Synchronous motor ,Finite element method - Abstract
This research is a proposal of a novel transfer device using a Transverse Flux-Flux Reversal Linear Motor (TF-FRLM). Transfer device in this paper is mounted on a carrier apparatus which was operated in parallel synchronous operation. This digest mainly discusses the overview of a novel transfer device and the optimization result of C-core TF-FRLM. The section of new transfer device describes the basic structure and basic operation. In the section on optimization, the results of dimensional change are shown on the graph and the optimum points are discussed. Three-dimensional finite element analysis is used for dimension optimization.
- Published
- 2019
25. Prediction of ductile fracture induced by contraction twinning in AZ31 sheet subjected to uniaxial and biaxial stretching modes
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Kengo Yoshida
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010302 applied physics ,Materials science ,business.industry ,Mechanical Engineering ,02 engineering and technology ,Slip (materials science) ,Structural engineering ,021001 nanoscience & nanotechnology ,01 natural sciences ,Finite element method ,Mechanics of Materials ,0103 physical sciences ,Volume fraction ,Formability ,General Materials Science ,Composite material ,0210 nano-technology ,Crystal twinning ,Ductility ,business ,Necking ,Plane stress - Abstract
The formability of AZ31 sheets was experimentally measured for uniaxial tension, plane strain stretching, and equi-biaxial stretching modes. The limit strain of the specimen was reasonable under uniaxial tension but was drastically reduced in the biaxial stretching modes. Full-field strain analysis and the observation of the fracture surface revealed that the specimen fractured without the formation of a visible local necking. To predict the fracture behavior using a crystal plasticity-based finite element method, a mean field model was developed to solve the mechanical interplay between the parent and twins. The destabilization of the specimen was simulated by introducing fracture criteria as functions of the accumulated slip inside the contraction twin region. Simulations revealed that strong strain heterogeneity forms in the case of the biaxial stretching modes, and this heterogeneity is apparently reduced under uniaxial tension as a result of the activation of prismatic slip, which produces a uniform strain distribution. Contraction twins nucleate at smaller strain levels in the biaxial stretching modes, and premature failure is predicted in the biaxial stretching modes as a result of the accumulation of slip in the twinned regions. Parametric studies show that even when the volume fraction of twins is small, they have a significant impact on the ductility of AZ31 sheets.
- Published
- 2016
26. Prediction of Sheet-Metal Formability with Crystal Plasticity Theory
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Kengo Yoshida
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Materials science ,Mechanics of Materials ,Mechanical Engineering ,visual_art ,visual_art.visual_art_medium ,Formability ,General Materials Science ,Composite material ,Sheet metal ,Crystal plasticity - Published
- 2016
27. Plastic flow behavior of fcc polycrystal subjected to nonlinear loadings over large strain range
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Kengo Yoshida and Narumasa Okada
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010302 applied physics ,Materials science ,Mechanical Engineering ,02 engineering and technology ,Kinematics ,Strain rate ,Plasticity ,021001 nanoscience & nanotechnology ,01 natural sciences ,Strain rate tensor ,Nonlinear system ,Mechanics of Materials ,0103 physical sciences ,Large strain ,Hardening (metallurgy) ,General Materials Science ,Crystallite ,Composite material ,0210 nano-technology - Abstract
Plastic flow rule is a fundamental equation that describes the plastic behavior of polycrystalline aggregate. To clarify plastic response at the point where the loading mode is suddenly changed, uniaxial tension followed by combined tension–torsion was applied to an A3003-O tube. The loading mode was altered at different plastic strains. It was observed that the direction of the plastic strain rate rotated immediately when the loading mode was changed. The greater the deviation in the subsequent loading mode from the uniaxial tension, the higher is the extent of rotation of the direction of plastic strain rate. The extent of instantaneous rotation of the plastic flow direction was the same regardless of the magnitude of the plastic strain at the alteration of the loading mode. Thus, the experimental results showed that the direction of the plastic flow depended on the direction of the stress/strain rate tensor; however, it was not affected by the magnitude of the plastic strain. Then, the effects of the hardening behavior of a slip system on the direction of the plastic flow were examined through a crystal plasticity simulation that considers the latent and kinematic hardenings. The crystal plasticity simulations reproduced the experimentally observed rotation of the plastic flow direction. Moreover, the simulations showed that the latent and kinematic hardenings did not affect the direction of the macroscopic plastic flow, even though they altered the activities of the slip systems. Therefore, it became clear that the plastic flow behavior of the polycrystal depends on the stress state and the direction of the stress/strain rate, and it is not affected by either the magnitude of the plastic strain or the hardening behavior of a slip system.
- Published
- 2020
28. Radiation- and Age-Associated Changes in Peripheral Blood Dendritic Cell Populations among Aging Atomic Bomb Survivors in Japan
- Author
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Junko Kajimura, Heather E. Lynch, Kengo Yoshida, Munechika Misumi, Waka Ohishi, Ivo D. Shterev, Yoichiro Kusunoki, Benjamin French, Mika Yamaoka, Seishi Kyoizumi, Susan Geyer, Kei Nakachi, Tomonori Hayashi, and Gregory D. Sempowski
- Subjects
Male ,0301 basic medicine ,Aging ,Biophysics ,Age and gender ,03 medical and health sciences ,0302 clinical medicine ,Japan ,Immunity ,Humans ,Medicine ,Radiology, Nuclear Medicine and imaging ,Survivors ,Aged ,Aged, 80 and over ,Nuclear Weapons ,Radiation ,Multivariable regression analysis ,business.industry ,Radiation dose ,Dose-Response Relationship, Radiation ,hemic and immune systems ,Dendritic Cells ,Dendritic cell ,Radiation Exposure ,Peripheral blood ,Radiation exposure ,030104 developmental biology ,Immunology ,Female ,business ,030215 immunology - Abstract
Previous immunological studies in atomic bomb survivors have suggested that radiation exposure leads to long-lasting changes, similar to immunological aging observed in T-cell-adaptive immunity. However, to our knowledge, late effects of radiation on dendritic cells (DCs), the key coordinators for activation and differentiation of T cells, have not yet been investigated in humans. In the current study, we hypothesized that numerical and functional decreases would be observed in relationship to radiation dose in circulating conventional DCs (cDCs) and plasmacytoid DCs (pDCs) among 229 Japanese A-bomb survivors. Overall, the evidence did not support this hypothesis, with no overall changes in DCs or functional changes observed with radiation dose. Multivariable regression analysis for radiation dose, age and gender effects revealed that total DC counts as well as subpopulation counts decreased in relationship to increasing age. Further analyses revealed that in women, absolute numbers of pDCs showed significant decreases with radiation dose. A hierarchical clustering analysis of gene expression profiles in DCs after Toll-like receptor stimulation in vitro identified two clusters of participants that differed in age-associated expression levels of genes involved in antigen presentation and cytokine/chemokine production in cDCs. These results suggest that DC counts decrease and expression levels of gene clusters change with age. More than 60 years after radiation exposure, we also observed changes in pDC counts associated with radiation, but only among women.
- Published
- 2017
29. Plastic deformation characteristics of light metal sheets—methods of measurement and modeling—
- Author
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Toshihiko Kuwabara and Kengo Yoshida
- Subjects
Materials science ,Mechanics of Materials ,Mechanical Engineering ,Materials Chemistry ,Metals and Alloys ,Composite material ,Light metal - Published
- 2015
30. Fate Decision Between Group 3 Innate Lymphoid and Conventional NK Cell Lineages by Notch Signaling in Human Circulating Hematopoietic Progenitors
- Author
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Kengo Yoshida, Yoichiro Kusunoki, Malcolm A.S. Moore, Seishi Kyoizumi, Marcel R.M. van den Brink, Yoshiko Kubo, Kei Nakachi, Junko Kajimura, and Tomonori Hayashi
- Subjects
0301 basic medicine ,Receptor expression ,Cellular differentiation ,T cell ,Immunology ,Notch signaling pathway ,Antigens, CD34 ,Biology ,03 medical and health sciences ,medicine ,Immunology and Allergy ,Humans ,Cell Lineage ,Lymphocytes ,Progenitor cell ,Cells, Cultured ,Interleukin-15 ,Natural Cytotoxicity Triggering Receptor 2 ,Receptors, Notch ,Interleukin-7 ,Innate lymphoid cell ,Immune System Development ,Cell Differentiation ,Hematopoietic Stem Cells ,Immunity, Innate ,Lymphocyte Subsets ,Cell biology ,Killer Cells, Natural ,Haematopoiesis ,030104 developmental biology ,medicine.anatomical_structure ,Interleukin 15 ,embryonic structures ,Signal Transduction - Abstract
The role of Notch signaling in human innate lymphoid cell (ILC) differentiation is unclear, although IL-7 and IL-15 promote differentiation of natural cytotoxicity receptor (NCR) NKp44+ group 3 ILCs (NCR+ILC3s) and conventional NK (cNK) cells from CD34+ hematopoietic progenitor cells (HPCs) ex vivo. In this study, we analyzed the functions of Notch in the differentiation of NCR+ILC3s and cNK cells from human HPC subpopulations circulating in peripheral blood by limiting dilution and clonal assays using high-throughput flow cytometry. We demonstrated that Notch signaling in combination with IL-7 induced NCR+ILC3 differentiation, but conversely suppressed IL-15–dependent cNK cell generation in CD45RA+Flt-3−c-Kitlow, a novel innate lymphocyte-committed HPC subpopulation. In contrast, Notch signaling induced CD45RA−Flt-3+c-Kithigh multipotent HPCs to generate CD34+CD7+CD62Lhigh, the earliest thymic progenitor–like cells, which preserved high cNK/T cell potential, but lost NCR+ILC3 potential. These findings implicate the countervailing functions of Notch signaling in the fate decision between NCR+ILC3 and cNK cell lineages at different maturational stages of human HPCs. Inhibition of Notch functions by Abs specific for either the Notch1 or Notch2 negative regulatory region suggested that both Notch1 and Notch2 signals were involved in the fate decision of innate lymphocyte-committed HPCs and in the generation of earliest thymic progenitor–like cells from multipotent HPCs. Furthermore, the synergistic interaction between Notch and IL-7 in NCR+ILC3 commitment was primarily explicable by the induction of IL-7 receptor expression in the innate lymphocyte–committed HPCs by Notch stimulation, suggesting the pivotal role of Notch in the transcriptional control required for human NCR+ILC3 commitment.
- Published
- 2017
31. Short-term Intervention Effects of Dual-task Training on Injury and Disability Rates in Young Soccer Players
- Author
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Hayato Inokuma, Yuko Takahashi, Shin Okazaki, Keisuke Hamada, Natsumi Chiba, Kazumasa Nakagawa, and Kengo Yoshida
- Subjects
medicine.medical_specialty ,business.industry ,Intervention (counseling) ,Injury prevention ,Closed eyes ,Physical therapy ,medicine ,Intervention effect ,Physical function ,Training program ,business ,Test (assessment) ,Task (project management) - Abstract
Background: In soccer performance, coordination training is important and there is a high chance of injury due to improper concentration during a performance, but there is little research on the relationship with injury. The aim of this study was to assess the effect of dual-task training on young soccer players' attention distribution ability, physical function and performance, and occurrence of injury. Methods: The subjects were 70 soccer players as intervention group and 52 players were as control group (age of all subjects was 15.9 ± 0.8 years, the height was 168.8 ± 5.3 cm, and the body weight was 59.5 ± 6.2 kg). Agility t-test and an original dual-task agility t-test were measured as indicator of attention distribution ability. The history of subjects’ injuries was interviewed, and a single-leg triple hop for the distance test and a single-leg standing test with closed eyes were measured as physical function. The dual-task training concluded 5 items and the intervention was performed in approximately 20 minutes one time and six times over 3 weeks at a frequency of twice weekly. The number of people with injuries in each group and each measurement value was compared in each group. Results: The control group comprised 10 subjects with injuries before intervention and 7 after intervention, whereas the intervention group comprised 12 subjects with injuries before intervention and 3 after intervention. No significant differences were observed in any of the parameters after the intervention in either of the two groups. Conclusion: Whether this difference was caused by the intervention remains unclear; however, it is possible that the training program in this study was effective for short-term injury prevention. The contents of evaluation and training menu should be reexamined in the future.
- Published
- 2017
32. Aging-related changes in human T-cell repertoire over 20years delineated by deep sequencing of peripheral T-cell receptors
- Author
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Seishi Kyoizumi, Tomonori Hayashi, Yoichiro Kusunoki, John B. Cologne, Kengo Yoshida, Kismet A. Cordova, Mika Yamaoka, Harlan Robins, and Munechika Misumi
- Subjects
0301 basic medicine ,Adult ,CD4-Positive T-Lymphocytes ,Male ,Aging ,Receptors, Antigen, T-Cell ,Complementarity determining region ,Biology ,CD8-Positive T-Lymphocytes ,Biochemistry ,Deep sequencing ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Endocrinology ,Immune system ,Antigen ,T-Lymphocyte Subsets ,Genetics ,Cytotoxic T cell ,Humans ,Molecular Biology ,Aged ,Sex Characteristics ,Repertoire ,T-cell receptor ,Cell Biology ,Middle Aged ,Clone Cells ,030104 developmental biology ,Female ,CD8 ,030215 immunology - Abstract
Recent deep sequencing studies on T-cell receptor (TCR) repertoire have provided robust data to characterize diversity of T-cell immune responsiveness to a wide variety of peptide antigens, including viral and tumor antigens. The human TCR repertoire declines with age, but this decline has not been fully investigated longitudinally in individuals. Using a deep sequencing approach, we analyzed TCRβ repertoires longitudinally over approximately 20years, with ages ranging from 23 to 50years at the start (23 to 65years overall), in peripheral-blood CD4 and CD8 T-cell populations that were collected and cryopreserved 3 times at intervals of approximately 10years from each of 6 healthy adults (3 men and 3 women). Sequence data at the hypervariable complementarity determining region 3 (CDR3) in the TCRB gene locus were evaluated by applying a random-coefficient statistical regression model. Two outcomes were analyzed: total number of distinct TCRB CDR3 sequences as a TCR diversity metric, and clonality of the T-cell populations. TCR repertoire diversity decreased (p
- Published
- 2017
33. 'Naked' Lithium Cation: Strongly Activated Metal Cations Facilitated by Carborane Anions
- Author
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Masanobu Uchiyama, Kengo Yoshida, Atsuya Muranaka, Ryo Takita, Seijiro Matsubara, and Yu Kitazawa
- Subjects
010405 organic chemistry ,Organic Chemistry ,Inorganic chemistry ,chemistry.chemical_element ,Alkylation ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Metal ,Organic reaction ,chemistry ,visual_art ,Polymer chemistry ,visual_art.visual_art_medium ,Carborane ,Lithium ,Reactivity (chemistry) ,Lithium Cation - Abstract
Experimental and spectroscopic studies revealed unprecedented reactivity of a “naked” lithium cation with very weakly coordinating anions, including carborane anions. The superactivated lithium cation has greatly enhanced Lewis acidic character and mediates various organic reactions such as carbonyl-ene reaction, NBS-bromination of unactivated aromatics, and Friedel–Crafts alkylation, which are not promoted by conventional lithium salts. Chemical robustness of the counteranion also plays an important role in the chemistry of the strongly activated lithium cation.
- Published
- 2017
34. Linkage between Dendritic and T Cell Commitments in Human Circulating Hematopoietic Progenitors
- Author
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Lauren F. Young, Junko Kajimura, Yoichiro Kusunoki, Seishi Kyoizumi, Marcel R.M. van den Brink, Tomonori Hayashi, Yoshiko Kubo, Kei Nakachi, Malcolm A.S. Moore, and Kengo Yoshida
- Subjects
Male ,T-Lymphocytes ,T cell ,Immunology ,CD34 ,Biology ,Article ,Mice ,Interleukin 21 ,medicine ,Animals ,Humans ,Immunology and Allergy ,Cytotoxic T cell ,Receptor, Notch1 ,Progenitor cell ,Antigen-presenting cell ,Multipotent Stem Cells ,Dendritic Cells ,Hematopoietic Stem Cells ,Haematopoiesis ,medicine.anatomical_structure ,Multipotent Stem Cell ,Cancer research ,Female - Abstract
The relationships between commitments of dendritic cells (DCs) and T cells in human hematopoietic stem cells are not well understood. In this study, we enumerate and characterize conventional DC and plasmacytoid DC precursors in association with T cell and thymus-derived types of NK cell precursors among CD34+ hematopoietic progenitor cells (HPCs) circulating in human peripheral blood. By limiting-dilution analyses using coculture with stroma cells expressing Notch1 ligand, the precursor frequencies (PFs) of DCs in HPCs were found to significantly correlate with T cell PFs, but not with NK cell PFs, among healthy donors. Clonal analyses showed that the majority of T/NK dual- and T single-lineage precursors—but only a minority of NK single-lineage precursors—were associated with the generation of DC progenies. All clones producing both DC and T cell progenies were found with monocyte and/or granulocyte progenies, suggesting DC differentiation via myeloid DC pathways. Analyses of peripheral blood HPC subpopulations revealed that the lineage split between DC and T/NK cell progenitor occurs at the stage prior to bifurcation into T and NK cell lineages. The findings suggest a strong linkage between DC and T cell commitments, which may be imprinted in circulating lymphoid-primed multipotent progenitors or in more upstream HPCs.
- Published
- 2014
35. 18π-Electron Tautomeric Benziphthalocyanine: A Functional Near-Infrared Dye with Tunable Aromaticity
- Author
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Naoyuki Toriumi, Masanobu Uchiyama, Keiichi Hirano, Atsuya Muranaka, Daisuke Hashizume, and Kengo Yoshida
- Subjects
Models, Molecular ,Molecular Structure ,Chemical modification ,Electrons ,Stereoisomerism ,Aromaticity ,General Chemistry ,Resorcinol ,General Medicine ,Photochemistry ,Tautomer ,Catalysis ,Solvent ,chemistry.chemical_compound ,chemistry ,Organometallic Compounds ,Phthalocyanine ,Moiety ,Benzimidazoles ,Spectroscopy ,Oxidation-Reduction - Abstract
Dihydroxybenziphthalocyanine 1, with bulky aryloxy groups, has been synthesized and characterized by X-ray crystallography, NMR and UV/Vis-NIR spectroscopy, and theoretical calculations. Macrocycle 1 is the first example of an aromatic benziphthalocyanine with an 18π-electron structure, and was found to exist as an equilibrium mixture of weakly aromatic and strongly aromatic tautomers. The aromaticity and near-IR absorption can be controlled by chemical modification at the reactive resorcinol moiety and by variation of the solvent.
- Published
- 2014
36. Effects of grain-scale heterogeneity on surface roughness and sheet metal necking
- Author
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Kengo Yoshida
- Subjects
Materials science ,Misorientation ,Mechanical Engineering ,Condensed Matter Physics ,Grain size ,Shear (sheet metal) ,Mechanics of Materials ,visual_art ,Free surface ,visual_art.visual_art_medium ,Surface roughness ,Formability ,General Materials Science ,Composite material ,Sheet metal ,Civil and Structural Engineering ,Necking - Abstract
Strain localization of sheet metals subjected to plane-strain stretching was simulated by finite-element analysis based on a crystal plasticity model. The ratio of specimen thickness to grain size, denoted by Ng, is varied from 1 to 70, and its influence on the evolution of surface roughness and the occurrence of sheet necking is investigated. Roughening of the free surface of the specimen is induced by the grain-scale strain heterogeneity associated with local grain misorientation. The magnitude of surface roughness depends mainly on the grain size and is less sensitive to Ng. As Ng decreases while maintaining the thickness, the magnitude of surface roughness becomes large with respect to the thickness. As a result, large geometrical imperfection is generated. Therefore, the formability of sheet metal is reduced as Ng decreases. Such an effect is found to be particularly considerable when Ng is less than 30. It is also found that the localization mode shifts from a sharp shear banding mode to a localized thinning mode as Ng increases.
- Published
- 2014
37. Work-hardening behavior of polycrystalline aluminum alloy under multiaxial stress paths
- Author
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Yuichi Tadano, Kengo Yoshida, and Asato Ishii
- Subjects
Materials science ,Stress path ,business.industry ,Mechanical Engineering ,Alloy ,Mechanics ,Work hardening ,Structural engineering ,Slip (materials science) ,Strain hardening exponent ,engineering.material ,Flow stress ,Plasticity ,Mechanics of Materials ,engineering ,Hardening (metallurgy) ,General Materials Science ,business - Abstract
A thin-walled tubular specimen of A3003-O is subjected to uniaxial, biaxial, and triaxial stress paths using an axial load-internal pressure-torsion type test machine. For linear multiaxial stress paths, the ratios of axial, circumferential, and shear stresses are kept constant, and the stress–strain relations for various stress paths are measured. The work-hardening behavior of the specimen is evaluated based on the plastic work per unit volume, and contours of equal plastic work are constructed. The shape of the contour changes progressively with increasing plastic strain. Therefore, the amount of work hardening of the specimen depends on the plastic work and the applied stress path. In order to clarify the source of such work-hardening behavior, numerical simulations are performed using the crystal plasticity model. Two hardening models are adopted. In one model, the slip resistance is given as a function of accumulated slip, and, in the other model, the slip resistance is given as a function of dislocation density. The evolution of macroscopic flow stress depends only on the plastic work for the accumulated-slip-based model, and this model cannot predict the experimental trend. On the other hand, the dislocation-density-based model reproduces the stress-path dependent work-hardening behavior observed in the experiments, although quantitative agreement is not fully achieved. In the simulation, the evolution rate of the dislocation density varies depending on the stress path, which is identified as the source of the stress-path-dependent work-hardening behavior.
- Published
- 2014
38. Formability simulation of based on crystal plasticity model for aluminum alloy sheets
- Author
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Kengo Yoshida
- Subjects
Materials science ,Mechanical Engineering ,Alloy ,Metallurgy ,Metals and Alloys ,chemistry.chemical_element ,engineering.material ,Crystal plasticity ,chemistry ,Mechanics of Materials ,Aluminium ,Materials Chemistry ,engineering ,Formability ,Composite material - Published
- 2014
39. Analysis of Joint Angle and Upper and Lower Thigh Rotation Movements in the Stance Phase of Walking by Subjects with Medial Knee Osteoarthritis
- Author
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Tatsuo Motoyama, Nobuhiro Kito, Masaya Anan, Sachie Sugawa, Takuro Aidu, Kengo Yoshida, Mahito Kawashima, Taizan Tanaka, Kiyotaka Hada, Kazuki Tokuda, and Koichi Shinkoda
- Subjects
medicine.medical_specialty ,business.industry ,Stance phase ,Physical Therapy, Sports Therapy and Rehabilitation ,Osteoarthritis ,Thigh ,medicine.disease ,Rotation ,Physical medicine and rehabilitation ,medicine.anatomical_structure ,Joint angle ,medicine ,business ,Medial knee - Published
- 2014
40. Numerical analysis of car drifting motion by tsunami using SPH method
- Author
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Wataru Sugiyama, Nobuatsu Tanaka, and Kengo Yoshida
- Subjects
Numerical analysis ,Mechanics ,Motion (physics) ,Geology - Published
- 2019
41. Plastic flow localization analysis of heterogeneous materials using homogenization-based finite element method
- Author
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Yuichi Tadano, Mitsutoshi Kuroda, and Kengo Yoshida
- Subjects
Materials science ,Finite element limit analysis ,business.industry ,Mechanical Engineering ,Constitutive equation ,Mechanics ,Structural engineering ,Mixed finite element method ,Condensed Matter Physics ,Homogenization (chemistry) ,Finite element method ,Mechanics of Materials ,Representative elementary volume ,General Materials Science ,business ,Civil and Structural Engineering ,Necking ,Plane stress - Abstract
A novel framework to predict the onset of plastic flow localization is presented. The proposed framework combines a classical strain localization analysis with a homogenization-based finite element method, and has high applicability to various types of material with a characteristic microstructure that may have significant heterogeneity as long as its representative volume element can be represented by a finite element discretization. According to the proposed method, a plastic flow localization analysis can be performed taking only one or two material points in macroscopic analysis. This means that localization analysis of materials involving very complex microstructures, which is hard to be satisfactorily treated in a fully micro-macro-coupled finite element analysis with the homogenization approach, can be carried out with a reasonable computational cost. As a practical application of the proposed general framework, a plane stress version, that is, a Marciniak–Kuczynski-type (M–K) approach, is considered, then the forming limit strains of FCC polycrystalline sheets are evaluated. Crystal plasticity theory is adopted as a constitutive model for each crystal grain, and the homogenization-based finite element method is used to evaluate the average material response to be used in M–K-type sheet necking analysis. A numerical convergence analysis is conducted to determine the appropriate size of the representative volume element in the homogenization, and the effect of the geometrical configuration of crystal grains is studied. Then, the forming limit strains of a textured material are evaluated. The computational results are compared with those obtained using the conventional Taylor-type polycrystalline model.
- Published
- 2013
42. Effects ofIL-10Haplotype and Atomic Bomb Radiation Exposure on Gastric Cancer Risk
- Author
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Keiko Sasaki, Masazumi Akahoshi, Kengo Yoshida, Ikue Hayashi, Reiko Ito, Yoichiro Kusunoki, Saeko Fujiwara, Kei Nakachi, John B. Cologne, Kazue Imai, Hiroko Nagamura, Yukari Morishita, Junko Kajimura, Waka Ohishi, Seishi Kyoizumi, Tomonori Hayashi, and Mayumi Maki
- Subjects
Adult ,Male ,Oncology ,medicine.medical_specialty ,Neoplasms, Radiation-Induced ,Biophysics ,Single-nucleotide polymorphism ,Radiation Dosage ,Polymorphism, Single Nucleotide ,Risk Factors ,Stomach Neoplasms ,Internal medicine ,Genotype ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Stomach cancer ,Aged ,Aged, 80 and over ,Genetics ,Nuclear Weapons ,Radiation ,business.industry ,Incidence (epidemiology) ,Haplotype ,Cancer ,Middle Aged ,medicine.disease ,Interleukin-10 ,Haplotypes ,Relative risk ,Cohort ,Female ,Gene-Environment Interaction ,business - Abstract
Gastric cancer (GC) is one of the cancers that reveal increased risk of mortality and incidence in atomic bomb survivors. The incidence of gastric cancer in the Life Span Study cohort of the Radiation Effects Research Foundation (RERF) increased with radiation dose (gender-averaged excess relative risk per Gy = 0.28) and remains high more than 65 years after exposure. To assess a possible role of gene-environment interaction, we examined the dose response for gastric cancer incidence based on immunosuppression-related IL-10 genotype, in a cohort study with 200 cancer cases (93 intestinal, 96 diffuse and 11 other types) among 4,690 atomic bomb survivors participating in an immunological substudy. Using a single haplotype block composed of four haplotype-tagging SNPs (comprising the major haplotype allele IL-10-ATTA and the minor haplotype allele IL-10-GGCG, which are categorized by IL-10 polymorphisms at -819AG and -592TG, +1177TC and +1589AG), multiplicative and additive models for joint effects of radiation and this IL-10 haplotyping were examined. The IL-10 minor haplotype allele(s) was a risk factor for intestinal type gastric cancer but not for diffuse type gastric cancer. Radiation was not associated with intestinal type gastric cancer. In diffuse type gastric cancer, the haplotype-specific excess relative risk (ERR) for radiation was statistically significant only in the major homozygote category of IL-10 (ERR = 0.46/Gy, P = 0.037), whereas estimated ERR for radiation with the minor IL-10 homozygotes was close to 0 and nonsignificant. Thus, the minor IL-10 haplotype might act to reduce the radiation related risk of diffuse-type gastric cancer. The results suggest that this IL-10 haplotyping might be involved in development of radiation-associated gastric cancer of the diffuse type, and that IL-10 haplotypes may explain individual differences in the radiation-related risk of gastric cancer.
- Published
- 2013
43. Age-Associated Changes in the Differentiation Potentials of Human Circulating Hematopoietic Progenitors to T- or NK-Lineage Cells
- Author
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Yoichiro Kusunoki, Lauren F. Young, Kengo Yoshida, Marcel R.M. van den Brink, Yoshiko Kubo, Junko Kajimura, Kei Nakachi, Tomonori Hayashi, Kazue Imai, Seishi Kyoizumi, and Malcolm A.S. Moore
- Subjects
Adult ,Aging ,T-Lymphocytes ,T cell ,Immunology ,Cell Separation ,Biology ,Article ,Immunophenotyping ,Interleukin 21 ,medicine ,Humans ,Immunology and Allergy ,Cytotoxic T cell ,Cell Lineage ,IL-2 receptor ,Antigen-presenting cell ,Janus kinase 3 ,Cell Differentiation ,Flow Cytometry ,Hematopoietic Stem Cells ,Natural killer T cell ,Coculture Techniques ,Cell biology ,Killer Cells, Natural ,medicine.anatomical_structure ,Interleukin 12 - Abstract
Age-associated changes of T and NK cell (T/NK) potential of human hematopoietic stem cells are unknown. In this study, we enumerate and characterize T/NK precursors among CD34+Lin− cell populations circulating in normal human adult peripheral blood (PB) by a limiting-dilution assay using coculture with OP9-DL1 stroma cells expressing Notch 1 ligand, Delta–like 1. The frequency of T cell precursors in CD34+Lin− cells was found to decrease with donor age, whereas the ratio of NK to T cell precursor frequency (NK/T ratio) increased with age, suggesting that lymphoid differentiation potential of PB progenitors shifts from T to NK cell lineage with aging. Clonal analyses of CD34+Lin− cells showed that differences in the NK/T ratio were attributable to different distributions of single- and dual-lineage T/NK precursor clones. Because nearly all of the clones retained monocyte and/or granulocyte differentiation potentials in coculture with OP9-DL1 cells, T/NK precursors in PB are considered to be contained in the pool of T/NK/myeloid multipotent progenitors. The age-associated increase in NK over T cell commitment might occur in precursor cells with T/NK/myeloid potential.
- Published
- 2013
44. Evaluation of Stress and Strain Measurement Accuracy in Hydraulic Bulge Test with the Aid of Finite-element Analysis
- Author
-
Kengo Yoshida
- Subjects
Engineering ,Accuracy and precision ,business.industry ,Mechanical Engineering ,Stress–strain curve ,Metals and Alloys ,Structural engineering ,Finite element method ,Finite element simulation ,Mechanics of Materials ,Bulge test ,Materials Chemistry ,Geotechnical engineering ,business - Published
- 2013
45. Long-Term Effects of Radiation Exposure and Metabolic Status on Telomere Length of Peripheral Blood T Cells in Atomic Bomb Survivors
- Author
-
Mika Yamaoka, Munechika Misumi, Seishi Kyoizumi, Yoshiko Kubo, Waka Ohishi, Yoichiro Kusunoki, Tomonori Hayashi, and Kengo Yoshida
- Subjects
0301 basic medicine ,Adult ,Male ,medicine.medical_specialty ,Aging ,Adolescent ,T-Lymphocytes ,Biophysics ,Biology ,Flow cytometry ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Immune system ,Internal medicine ,medicine ,Cytotoxic T cell ,Humans ,Radiology, Nuclear Medicine and imaging ,Survivors ,Child ,Aged ,Aged, 80 and over ,Nuclear Weapons ,Radiation ,medicine.diagnostic_test ,Infant ,Middle Aged ,Radiation Exposure ,Telomere ,Peripheral blood ,Peripheral ,Radiation exposure ,030104 developmental biology ,Endocrinology ,030220 oncology & carcinogenesis ,Child, Preschool ,Immunology ,Female ,Fluorescence in situ hybridization - Abstract
In a series of studies of atomic bomb survivors, radiation-dose-dependent alterations in peripheral T-cell populations have been reported. For example, reduced size in naïve T-cell pools and impaired proliferation ability of T cells were observed. Because these alterations are also generally observed with human aging, we hypothesized that radiation exposure may accelerate the aging process of the T-cell immune system. To further test this hypothesis, we conducted cross-sectional analyses of telomere length, a hallmark of cellular aging, of naïve and memory CD4 T cells and total CD8 T cells in the peripheral blood of 620 atomic bomb survivors as it relates to age and radiation dose, using fluorescence in situ hybridization with flow cytometry. Since telomere shortening has been recently demonstrated in obesity-related metabolic abnormalities and diseases, the modifying effects of metabolic status were also examined. Our results indicated nonlinear relationships between T-cell telomere length and prior radiation exposure, i.e., longer telomeres with lower dose exposure and a decreasing trend of telomere length with individuals exposed to doses higher than 0.5 Gy. There were associations between shorter T-cell telomeres and higher hemoglobin Alc levels or fatty liver development. In naïve and memory CD4 T cells, radiation dose and high-density lipoprotein (HDL) cholesterol were found to positively interact with telomere length, suggesting that the decreasing trend of telomere length from a higher radiation dose was less conspicuous in individuals with a higher HDL cholesterol. It is therefore likely that radiation exposure perturbs T-cell homeostasis involving telomere length maintenance by multiple biological mechanisms, depending on dose, and that long-term-radiation-induced effects on the maintenance of T-cell telomeres may be modified by the subsequent metabolic conditions of individuals.
- Published
- 2016
46. A Verification Method for Testing Abrasion in the Use of Restraint Type Personal Care Robots
- Author
-
Mao Xuewei, Kengo Yoshida, Shogo Okamoto, Yasuhiro Akiyama, and Yoji Yamada
- Subjects
Engineering ,Physical stress ,Personal care ,business.industry ,Testbed ,Shear stress ,Robot ,Porcine skin ,Manipulator ,business ,Simulation ,Abrasion (geology) - Abstract
Physical stress hazards are identified as a part of the safety requirements for personal care robots as described in ISO 13482. We conducted a safety verification study to clarify an inherently safe condition region in the shear stress—time relationship: The higher the shear stress is, the smaller number of times is needed for blister generation. For validating the verified safety data, we also built a testbed where a manipulator is used to optimally control the position and force of a cuff in contact with a piece of porcine skin for the purpose of reproducing the contact conditions as close as possible to those obtained when a human wears a robot.
- Published
- 2016
47. Metabolic Profile as a Potential Modifier of Long-Term Radiation Effects on Peripheral Lymphocyte Subsets in Atomic Bomb Survivors
- Author
-
Yoichiro Kusunoki, Seishi Kyoizumi, Waka Ohishi, Ayumi Hida, Eiji Nakashima, Tomonori Hayashi, Kengo Yoshida, and Masayuki Hakoda
- Subjects
0301 basic medicine ,Adult ,Male ,medicine.medical_specialty ,Aging ,Time Factors ,Adolescent ,Lymphocyte ,Biophysics ,Biology ,Radiation Dosage ,03 medical and health sciences ,chemistry.chemical_compound ,Young Adult ,0302 clinical medicine ,Immune system ,Internal medicine ,Diabetes mellitus ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Obesity ,Survivors ,Child ,Aged ,Aged, 80 and over ,Nuclear Weapons ,Radiation ,Triglyceride ,Cholesterol ,Fatty liver ,Middle Aged ,Radiation Exposure ,medicine.disease ,Radiation effect ,Lymphocyte Subsets ,030104 developmental biology ,medicine.anatomical_structure ,Endocrinology ,chemistry ,030220 oncology & carcinogenesis ,Child, Preschool ,Metabolome ,Female ,Body mass index - Abstract
Immune system impairments reflected by the composition and function of circulating lymphocytes are still observed in atomic bomb survivors, and metabolic abnormalities including altered blood triglyceride and cholesterol levels have also been detected in such survivors. Based on closely related features of immune and metabolic profiles of individuals, we investigated the hypothesis that long-term effects of radiation exposure on lymphocyte subsets might be modified by metabolic profiles in 3,113 atomic bomb survivors who participated in health examinations at the Radiation Effect Research Foundation, Hiroshima and Nagasaki, in 2000-2002. The lymphocyte subsets analyzed involved T-, B- and NK-cell subsets, and their percentages in the lymphocyte fraction were assessed using flow cytometry. Health examinations included metabolic indicators, body mass index, serum levels of total cholesterol, high-density lipoprotein cholesterol, C-reactive protein and hemoglobin A1c, as well as diabetes and fatty liver diagnoses. Standard regression analyses indicated that several metabolic indicators of obesity/related disease, particularly high-density lipoprotein cholesterol levels, were positively associated with type-1 helper T- and B-cell percentages but were inversely associated with naive CD4 T and NK cells. A regression analysis adjusted for high-density lipoprotein cholesterol revealed a radiation dose relationship with increasing NK-cell percentage. Additionally, an interaction effect was suggested between radiation dose and C-reactive protein on B-cell percentage with a negative coefficient of the interaction term. Collectively, these findings suggest that radiation exposure and subsequent metabolic profile changes, potentially in relationship to obesity-related inflammation, lead to such long-term alterations in lymphocyte subset composition. Because this study is based on cross-sectional and exploratory analyses, the implications regarding radiation exposure, metabolic profiles and circulating lymphocytes warrant future longitudinal and molecular mechanistic studies.
- Published
- 2016
48. Direct Hydroxylation and Amination of Arenes via Deprotonative Cupration
- Author
-
Chao Wang, Masanobu Uchiyama, Keiichi Hirano, Tatsuo Saito, Kengo Yoshida, Kohei Shimojo, Shinsuke Komagawa, Noriyuki Tezuka, Kazunori Miyamoto, and Ryo Takita
- Subjects
010405 organic chemistry ,chemistry.chemical_element ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Medicinal chemistry ,Redox ,Copper ,Catalysis ,0104 chemical sciences ,Hydroxylation ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,chemistry ,Functional group ,Organic chemistry ,Phenols ,Chemoselectivity ,Amination - Abstract
Deprotonative directed ortho cupration of aromatic/heteroaromatic C–H bond and subsequent oxidation with t-BuOOH furnished functionalized phenols in high yields with high regio- and chemoselectivity. DFT calculations revealed that this hydroxylation reaction proceeds via a copper (I → III → I) redox mechanism. Application of this reaction to aromatic C–H amination using BnONH2 efficiently afforded the corresponding primary anilines. These reactions show broad scope and good functional group compatibility. Catalytic versions of these transformations are also demonstrated.
- Published
- 2016
49. Relationship between spontaneous γH2AX foci formation and progenitor functions in circulating hematopoietic stem and progenitor cells among atomic-bomb survivors
- Author
-
Marcel R.M. van den Brink, Yoshiko Kubo, Kei Nakachi, Waka Ohishi, Yoichiro Kusunoki, Jae-Hung Shieh, Malcolm A.S. Moore, Munechika Misumi, Kengo Yoshida, Seishi Kyoizumi, Tomonori Hayashi, Lauren F. Young, Junko Kajimura, Kazue Imai, and Nan-ping Weng
- Subjects
0301 basic medicine ,DNA damage ,Health, Toxicology and Mutagenesis ,Cellular differentiation ,CD34 ,Biology ,Article ,Histones ,03 medical and health sciences ,0302 clinical medicine ,Genetics ,Humans ,Peripheral blood cell ,Progenitor cell ,Aged ,Aged, 80 and over ,Stem Cells ,Age Factors ,Cell Differentiation ,Middle Aged ,Hematopoietic Stem Cells ,humanities ,Haematopoiesis ,030104 developmental biology ,030220 oncology & carcinogenesis ,Immunology ,Cancer research ,Radiation Induced DNA Damage ,Stem cell ,DNA Damage - Abstract
Accumulated DNA damage in hematopoietic stem cells is a primary mechanism of aging-associated dysfunction in human hematopoiesis. About 70 years ago, atomic-bomb (A-bomb) radiation induced DNA damage and functional decreases in the hematopoietic system of A-bomb survivors in a radiation dose-dependent manner. The peripheral blood cell populations then recovered to a normal range, but accompanying cells derived from hematopoietic stem cells still remain that bear molecular changes possibly caused by past radiation exposure and aging. In the present study, we evaluated radiation-related changes in the frequency of phosphorylated (Ser-139) H2AX (γH2AX) foci formation in circulating CD34-positive/lineage marker-negative (CD34 + Lin−) hematopoietic stem and progenitor cells (HSPCs) among 226Hiroshima A-bomb survivors. An association between the frequency of γH2AX foci formation in HSPCs and the radiation dose was observed, but the γH2AX foci frequency was not significantly elevated by past radiation. We found a negative correlation between the frequency of γH2AX foci formation and the length of granulocyte telomeres. A negative interaction effect between the radiation dose and the frequency of γH2AX foci was suggested in a proportion of a subset of HSPCs as assessed by the cobblestone area-forming cell assay (CAFC), indicating that the self-renewability of HSPCs may decrease in survivors who were exposed to a higher radiation dose and who had more DNA damage in their HSPCs. Thus, although many years after radiation exposure and with advancing age, the effect of DNA damage on the self-renewability of HSPCs may be modified by A-bomb radiation exposure.
- Published
- 2016
50. Long term effects of radiation exposure on telomere lengths of leukocytes and its associated biomarkers among atomic-bomb survivors
- Author
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Susan Geyer, Mayumi Maki, Kyoji Furukawa, Tomonori Hayashi, Yoichiro Kusunoki, Alvin Shi, Kengo Yoshida, Kei Nakachi, Hiroko Nagamura, Junko Kajimura, Waka Ohishi, Keiko Sasaki, Ivo D. Shterev, Yiqun Hu, Ana Lustig, Yukari Morishita, Seishi Kyoizumi, Nan ping Weng, and Ikue Hayashi
- Subjects
0301 basic medicine ,Gerontology ,Male ,medicine.medical_specialty ,Aging ,Hiroshima ,Dependent manner ,leukocytes ,T cell ,Ionizing radiation ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Research Paper: Gerotarget (Focus on Aging) ,Japan ,Internal medicine ,Radiation, Ionizing ,Biomarkers, Tumor ,Medicine ,Humans ,Longitudinal Studies ,Survivors ,Telomere Shortening ,Aged ,Aged, 80 and over ,Nuclear Weapons ,business.industry ,Gerotarget ,Age Factors ,Middle Aged ,Radiation Exposure ,Telomere ,telomeres ,Cell function ,Radiation exposure ,030104 developmental biology ,Endocrinology ,medicine.anatomical_structure ,Cross-Sectional Studies ,Oncology ,chemistry ,030220 oncology & carcinogenesis ,Uric acid ,Female ,business ,ionizing radiation ,Biomarkers ,Follow-Up Studies - Abstract
Ionizing radiation (IR) is a major source of cellular damage and the immediate cellular response to IR has been well characterized. But the long-term impact of IR on cell function and its relationship with aging are not known. Here, we examined the IR effects on telomere length and other biomarkers 50 to 68 years post-exposure (two time points per person) in survivors of the atomic bombing at Hiroshima during WWII. We found that telomere length of leukocytes was inversely correlated with the dose of IR (p=0.008), and this effect was primarily found in survivors who were exposed at younger ages; specifically those
- Published
- 2016
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