31 research outputs found

    Nucleon structure from 2+1 flavor lattice QCD near the physical point

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    We present an update on our results of nucleon form factors measured on a large-volume lattice (8.1fm)4(8.1\rm{fm})^4 at almost the physical point in 2+1 flavor QCD. The configurations are generated with the stout-smeared O(a)\mathcal{O}(a) improved Wilson quark action and Iwasaki gauge action at β=1.82\beta = 1.82, which corresponds to the lattice spacing of 0.085 fm. The pion mass at the simulation point is about 145 MeV. We determine the iso- vector electric radius and magnetic moment from nucleon electric (GEG_E) and magnetic (GMG_M) form factors. We also report on preliminary results of the axial-vector (FAF_A), induced pseudo-scalar (FPF_P) and pseudo-scalar (GPG_P) form factors in order to verify the axial Ward- Takahashi identity in terms of the nucleon matrix elements, which may be called as the generalized Goldberger-Treiman relation.Comment: 8 pages, 12 figures; talk presented at the 35th International Symposium on Lattice Field Theory, 18-24 June 2017, Granada, Spai

    Functional visualization of NK Cell-mediated killing of metastatic single tumor cells

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    ナチュラルキラー(NK)細胞による転移がん細胞殺傷の可視化 --NK細胞とがん細胞の肺毛細血管上での戦いを実況中継する--. 京都大学プレスリリース. 2022-02-07.Natural killer (NK) cells lyse invading tumor cells to limit metastatic growth in the lung, but how some cancers evade this host protective mechanism to establish a growing lesion is unknown. Here we have combined ultra-sensitive bioluminescence imaging with intravital two-photon microscopy involving genetically-encoded biosensors to examine this question. NK cells eliminated disseminated tumor cells from the lung within 24 hrs of arrival, but not thereafter. Intravital dynamic imaging revealed that 50% of NK-tumor cell encounters lead to tumor cell death in the first 4 hrs after tumor cell arrival, but after 24 hrs of arrival, nearly 100% of the interactions result in the survival of the tumor cell. During this 24 hrs period, the probability of ERK activation in NK cells upon encountering the tumor cells was decreased from 68% to 8%, which correlated with the loss of the activating ligand CD155/PVR/Necl5 from the tumor cell surface. Thus, by quantitatively visualizing the NK-tumor cell interaction at the early stage of metastasis, we have revealed the crucial parameters of NK cell immune surveillance in the lung

    Nucleon form factors on a large volume lattice near the physical point in 2+1 flavor QCD

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    We present results for the isovector nucleon form factors measured on a 964 lattice at almost the physical pion mass with a lattice spacing of 0.085 fm in 2+1 flavor QCD. The configurations are generated with the stout-smeared O(a)-improved Wilson quark action and the Iwasaki gauge action at β=1.82. The pion mass at the simulation point is about 146 MeV. A large spatial volume of (8.1  fm)3 allows us to investigate the form factors in the small momentum transfer region. We determine the isovector electric radius and magnetic moment from nucleon electric (GE) and magnetic (GM) form factors as well as the axial-vector coupling gA. We also report on the results of the axial-vector (FA), induced pseudoscalar (FP) and pseudoscalar (GP) form factors in order to verify the axial Ward-Takahashi identity in terms of the nucleon matrix elements, which may be called the generalized Goldberger-Treiman relation

    Association Between PSCA Variants and Duodenal Ulcer Risk

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    Background: While duodenal ulcer (DU) and gastric cancer (GC) are both H. pylori infection-related diseases, individuals with DU are known to have lower risk for GC. Many epidemiological studies have identified the PSCA rs2294008 T-allele as a risk factor of GC, while others have found an association between the rs2294008 C-allele and risk of DU and gastric ulcer (GU). Following these initial reports, however, few studies have since validated these associations. Here, we aimed to validate the association between variations in PSCA and the risk of DU/GU and evaluate its interaction with environmental factors in a Japanese population. Methods: Six PSCA SNPs were genotyped in 584 DU cases, 925 GU cases, and 8,105 controls from the Japan Multi-Institutional Collaborative Cohort (J-MICC). Unconditional logistic regression models were applied to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between the SNPs and risk of DU/GU. Results: PSCA rs2294008 C-allele was associated with per allele OR of 1.34 (95% CI, 1.18–1.51; P = 2.28 × 10−6) for the risk of DU. This association was independent of age, sex, study site, smoking habit, drinking habit, and H. pylori status. On the other hand, we did not observe an association between the risk of GU and PSCA SNPs. Conclusions: Our study confirms an association between the PSCA rs2294008 C-allele and the risk of DU in a Japanese population

    Nucleon structure from 2+1 flavor lattice QCD near the physical point

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    We present an update on our results of nucleon form factors measured on a large-volume lattice (8:1fm)4 at almost the physical point in 2+1 flavor QCD. The configurations are generated with the stout-smeared O(a) improved Wilson quark action and Iwasaki gauge action at β = 1:82, which corresponds to the lattice spacing of 0.085 fm. The pion mass at the simulation point is about 145 MeV. We determine the isovector electric radius and magnetic moment from nucleon electric (GE) and magnetic (GM) form factors. We also report on preliminary results of the axial-vector (FA), induced pseudo-scalar (FP) and pseudo-scalar (GP) form factors in order to verify the axial Ward-Takahashi identity in terms of the nucleon matrix elements, which may be called as the generalized Goldberger-Treiman relation

    Geometry-Based Self-Assembly of Histone-DNA Nanostructures at Single-Nucleotide Resolution

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    Histones are basic protein monomers capable of interacting with DNA, providing the mechanism of DNA compaction inside the cell nucleus. The well-ordered assembly process of histone and DNA is a potential candidate as the approach for building DNA-protein nanostructures. Here, utilizing the sequence-independent histone-DNA interaction, we present an approach to self-assemble histones and single-stranded DNA (ssDNA) to form well-defined histone-DNA (sHD) nanoparticles and their multidimensional cross-linked complexes (cHD). By using various molecular biology and microscopy techniques, we elucidate the structure of these complexes, and we show that they are formed at carefully controlled conditions of temperature, ionic strength, concentration, and incubation time. We also demonstrate using a set of ssDNA molecular rulers and a geometric accommodation model that the assembly of sHD and cHD particles proceeds with precise geometry so that the number of ssDNA in these particles can be programmed by the length of ssDNA. We further show that the formation of cHD amplifies the effect of the length of ssDNA on the self-assembly, allowing for distinguishing ssDNA of different lengths at single nucleotide resolution. We envision that our geometry-directed approach of self-assembling histone-DNA nanostructures and the fundamental insights can serve as a structural platform to advance building precisely ordered DNA-protein nanostructures
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