172 research outputs found

    Spectroscopic estimation of the photon number for superconducting Kerr parametric oscillators

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    Quantum annealing (QA) is a way to solve combinational optimization problems. Kerr nonlinear parametric oscillators (KPOs) are promising devices for implementing QA. When we solve the combinational optimization problems using KPOs, it is necessary to precisely control the photon number of the KPOs. Here, we propose a feasible method to estimate the photon number of the KPO. We consider coupling an ancillary qubit to the KPO and show that spectroscopic measurements on the ancillary qubit provide information on the photon number of the KPO

    Flattened 1D fragments of fullerene C₆₀ that exhibit robustness toward multi-electron reduction

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    フラーレンに迫る電子受容能をもつ平坦な一次元π共役炭化水素の開発. 京都大学プレスリリース. 2023-05-15.Flat fullerene fragments attractive to electrons. 京都大学プレスリリース. 2023-06-01.Fullerenes are compelling molecular materials owing to their exceptional robustness toward multi-electron reduction. Although scientists have attempted to address this feature by synthesizing various fragment molecules, the origin of this electron affinity remains unclear. Several structural factors have been suggested, including high symmetry, pyramidalized carbon atoms, and five-membered ring substructures. To elucidate the role of the five-membered ring substructures without the influence of high symmetry and pyramidalized carbon atoms, we herein report the synthesis and electron-accepting properties of oligo(biindenylidene)s, a flattened one-dimensional fragment of fullerene C₆₀. Electrochemical studies corroborated that oligo(biindenylidene)s can accept electrons up to equal to the number of five-membered rings in their main chains. Moreover, ultraviolet/visible/near-infrared absorption spectroscopy revealed that oligo(biindenylidene)s exhibit enhanced absorption covering the entire visible region relative to C₆₀. These results highlight the significance of the pentagonal substructure for attaining stability toward multi-electron reduction and provide a strategy for the molecular design of electron-accepting π-conjugated hydrocarbons even without electron-withdrawing groups

    Polycomb-Mediated Loss of miR-31 Activates NIK-Dependent NF-κB Pathway in Adult T Cell Leukemia and Other Cancers

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    SummaryConstitutive NF-κB activation has causative roles in adult T cell leukemia (ATL) caused by HTLV-1 and other cancers. Here, we report a pathway involving Polycomb-mediated miRNA silencing and NF-κB activation. We determine the miRNA signatures and reveal miR-31 loss in primary ATL cells. MiR-31 negatively regulates the noncanonical NF-κB pathway by targeting NF-κB inducing kinase (NIK). Loss of miR-31 therefore triggers oncogenic signaling. In ATL cells, miR-31 level is epigenetically regulated, and aberrant upregulation of Polycomb proteins contribute to miR-31 downregulation in an epigenetic fashion, leading to activation of NF-κB and apoptosis resistance. Furthermore, this emerging circuit operates in other cancers and receptor-initiated NF-κB cascade. Our findings provide a perspective involving the epigenetic program, inflammatory responses, and oncogenic signaling

    Hyperefficient PrP Sc amplification of mouse-adapted BSE and scrapie strain by protein misfolding cyclic amplification technique.

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    Abnormal forms of prion protein (PrP(Sc)) accumulate via structural conversion of normal PrP (PrP(C)) in the progression of transmissible spongiform encephalopathy. Under cell-free conditions, the process can be efficiently replicated using in vitro PrP(Sc) amplification methods, including protein misfolding cyclic amplification. These methods enable ultrasensitive detection of PrP(Sc); however, there remain difficulties in utilizing them in practice. For example, to date, several rounds of protein misfolding cyclic amplification have been necessary to reach maximal sensitivity, which not only take several weeks, but also result in an increased risk of contamination. In this study, we sought to further promote the rate of PrP(Sc) amplification in the protein misfolding cyclic amplification technique using mouse transmissible spongiform encephalopathy models infected with either mouse-adapted bovine spongiform encephalopathy or mouse-adapted scrapie, Chandler strain. Here, we demonstrate that appropriate regulation of sonication dramatically accelerates PrP(Sc) amplification in both strains. In fact, we reached maximum sensitivity, allowing the ultrasensitive detection of < 1 LD(50) of PrP(Sc) in the diluted brain homogenates, after only one or two reaction rounds, and in addition, we detected PrP(Sc) in the plasma of mouse-adapted bovine spongiform encephalopathy-infected mice. We believe that these results will advance the establishment of a fast, ultrasensitive diagnostic test for transmissible spongiform encephalopathies.The definitive version is available at www.blackwell-synergy.co
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