101 research outputs found

    Integral Operators in Crack Problems and their Perturbations in the Direction of the Crack Extension

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    The perturbation, in the direction of the crack extension, of the elastostatic hypersingular integral operator for crack problems is calculated rigorously. A variational form including this perturbation is written in terms of the energy release rate. The obtained result is applied to Griffith's crack extension

    MK-801 blocks monoamine transporters expressed in HEK cells

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    Abstract(+)-MK-801 is known to be a specific non-competitive antagonist of N-methyl-d-aspartate (NMDA) receptors. However, besides having an anticonvulsant effect, this compound possesses a central sympathomimetic effect and an anxiolytic-like action, raising the possibility that (+)-MK-801 might affect monoamine uptake systems. To elucidate this possibility, we investigated the effects of (+)-MK-801 on monoamine transporters expressed in HEK cells. (+)-MK-801 significantly inhibited the uptake of all three monoamine transporters in a dose-dependent manner and the inhibitions were competitive with respect to monoamines. The Ki values of (+)-MK-801 on the norepinephrine, dopamine and serotonin transporters were 3.2 μM, 40 μM and 43 μM, respectively. In addition, (−)-MK-801, a less potent antagonist of NMDA receptors, also inhibited monoamine transporters with a similar potency as that of (+)-MK-801. These results clearly indicate that MK-801, a non-competitive antagonist of NMDA receptors, competitively inhibits monoamine transporters without stereoselectivity

    Retrieving the ground state of spin glasses using thermal noise: Performance of quantum annealing at finite temperatures

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    We study the problem to infer the ground state of a spin-glass Hamiltonian using data from another Hamiltonian with interactions disturbed by noise from the original Hamiltonian, motivated by the ground-state inference in quantum annealing on a noisy device. It is shown that the average Hamming distance between the inferred spin configuration and the true ground state is minimized when the temperature of the noisy system is kept at a finite value, and not at zero temperature. We present a spin-glass generalization of a well-established result that the ground state of a purely ferromagnetic Hamiltonian is best inferred at a finite temperature in the sense of smallest Hamming distance when the original ferromagnetic interactions are disturbed by noise. We use the numerical transfer-matrix method to establish the existence of an optimal finite temperature in one- and two-dimensional systems. Our numerical results are supported by mean-field calculations, which give an explicit expression of the optimal temperature to infer the spin-glass ground state as a function of variances of the distributions of the original interactions and the noise. The mean-field prediction is in qualitative agreement with numerical data. Implications on postprocessing of quantum annealing on a noisy device are discussed.Comment: 9 pages, 4 figures v2: updated to published versio

    Solitary Cardiac Metastasis of Hepatocellular Carcinoma

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    Cardiac metastasis originating from hepatocellular carcinoma (HCC) is a rare condition with a poor prognosis. No therapeutic standards for cardiac metastasis originating from HCC have been established. At 19 months after a curative hepatectomy, a 64-year-old Japanese hepatitis B virus-positive male patient experienced solitary cardiac metastasis originating from HCC. The cardiac tumor was discovered in the right ventricle. The patient received three courses of radiotherapy and chemotherapy and survived > 3 years after the initial diagnosis of cardiac metastasis. His case demonstrates that radiotherapy combined with chemotherapy can be an effective treatment for cardiac metastasis

    The Late Phase/Early Phase Ratio of Pancreatic CT Values as a Novel Predictor of Pancreatic Fistula after Distal Pancreatectomy

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    Post-operative pancreatic fistula (POPF) remains the most common complication after distal pancreatectomy (DP). In this retrospective study, we reviewed the data from patients who underwent DP between 2008 and 2019 in our institute to determine whether the late phase/early phase ratio (L/E ratio) by preoperative computed tomography (CT) scan in the pancreas could predict POPF occurrence after DP. We examined the relationship between preoperative or intraoperative factors and the occurrence of POPF after DP using statistical methods in 23 males and 21 females with a mean age of 73. The mean L/E ratio was significantly lower in the POPF group than the non-POPF group (p=0.035). The L/E ratio had moderate diagnostic accuracy, with a calculated optimal cutoff value of 0.77. In univariate analysis, a significant association was noted between POPF and stump thickness ≥ 16.9, body mass index ≥ 27.5, and L/E ratio ≤ 0.77. In the multivariate analysis, the L/E ratio (odds ratio, 5.96; p=0.036) was an independent risk factor for POPF. Our findings suggest that the pancreatic L/E ratio may predict the occurrence of POPF after DP. This measure may be useful in preoperative risk stratification, patient counseling, and perioperative patient management, improving clinical outcomes after DP
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