Publications by authors named "Yoichi Ikeda"

Background: The COVID-19 pandemic has caused serious health, economic, and social consequences worldwide. Understanding how infectious diseases spread can help mitigate these impacts. The Theil index, a measure of inequality rooted in information theory, is useful for identifying geographic disproportionality in COVID-19 incidence across regions.

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Article Synopsis
  • The study investigates the spin dynamics of the van der Waals antiferromagnet FeGaS using various techniques like magnetometry and neutron scattering, focusing on understanding its spin relaxation time across a vast range.
  • Although the temperature-dependent properties resemble those of a typical spin-glass transition, the observed nonlinear susceptibilities suggest that different mechanisms are at play, particularly around the anomalous temperature T∗=16.87(7) K.
  • The combination of elastic neutron scattering and muon measurements reveals a slowly fluctuating spin state above T∗, indicating that FeGaS offers opportunities to explore complex spin correlations in two-dimensional magnetic systems.
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Proton conductors have potential applications such as fuel cells, electrolysis cells, and sensors. These applications require new materials with high proton conductivity and high chemical stability at intermediate temperatures. Herein we report a series of new hexagonal perovskite-related oxides, BaAlSnO ( = Gd, Dy, Ho, Y, Er, Tm, and Yb).

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Producing a polarized lanthanum (La) target with high polarization and long relaxation time is crucial for realizing time-reversal violation experiments using polarized neutron beams. We use a LaAlO3 crystal doped with a small amount of Nd3+ ions for the polarized lanthanum target. Optimizing the amount of Nd3+ ions is considerably important because the achievable polarization and relaxation time strongly depend on this amount.

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Article Synopsis
  • High-output stomas (HOSs) can lead to dehydration and malnutrition in patients post-rectal cancer surgery, impacting their quality of life.
  • In a study of 31 patients, 9 experienced HOS, defined by an output of 2,000 ml or more per day, with no significant differences in clinicopathological features between those who developed HOS and those who did not.
  • Lower hemoglobin levels (under 12 mg/dl) and longer surgery times (300 minutes or more) were identified as potential risk factors for the development of HOS, suggesting a need for further research to confirm these predictors.
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The doubly charmed tetraquark T_{cc}^{+} recently discovered by the LHCb Collaboration is studied on the basis of (2+1)-flavor lattice QCD simulations of the D^{*}D system with nearly physical pion mass m_{π}=146  MeV. The interaction of D^{*}D in the isoscalar and S-wave channel, derived from the hadronic spacetime correlation by the HAL QCD method, is attractive for all distances and leads to a near-threshold virtual state with a pole position E_{pole}=-59(_{-99}^{+53})(_{-67}^{+2})  keV and a large scattering length 1/a_{0}=0.05(5)(_{-2}^{+2})  fm^{-1}.

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Background/aim: Anastomotic leakage (AL) is a serious complication after esophagectomy, and the refractory fistula (RF) following AL is therapeutically challenging with no optimal management strategies known. Thus, new therapeutic options are required for treating RF.

Case Report: A 67-year-old man who underwent endoscopic mucosal dissection was subjected to subtotal esophagectomy and reconstruction with a gastric tube through the retrosternal route with cervical anastomosis as additional therapy.

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Background/aim: Laparoscopic gastrectomy (LG) may have greater clinical benefits as a less invasive surgery for elderly patients with gastric cancer (GC). Therefore, we aimed to evaluate the survival benefit of LG in elderly patients with GC, especially focusing on preoperative comorbidities, and nutritional and inflammatory status.

Patients And Methods: Data collected from 115 patients aged ≥75 years with primary GC who underwent curative gastrectomy, comprising 58 patients who underwent open gastrectomy (OG) and 57 patients who underwent LG, were retrospectively reviewed (total cohort), and 72 propensity-matched patients (matched cohort) were selected for survival analysis.

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Background: Chemotherapy and chemoradiotherapy are common treatments for esophageal squamous cell carcinoma with distant metastasis; however, the prognosis remains poor, and complete remission is difficult to achieve. Here, we report a case of an older adult patient with esophageal squamous cell carcinoma who underwent surgery following combined treatment of immunotherapy and chemotherapy and achieved pathological complete response.

Case Presentation: An 80-year-old woman presenting with difficulty swallowing was referred to our hospital.

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Introduction And Importance: Atraumatic splenic rupture (ASR) is a rare state that accounts for only <1 % of splenic ruptures. One of the causes of ASR is splenic neoplasm such as angiosarcoma. The treatment strategy for ASR is still unclear given the small number of cases reported in detail.

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We propose a new compartment model of COVID-19 spread, the broken-link model, which includes the effect from unconnected infectious links of the transmission. The traditional SIR-type epidemic models are widely used to analyze the spread status, and the models show the exponential growth of the number of infected people. However, even in the early stage of the spread, it is proven by the actual data that the exponential growth did not occur all over the world.

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We report room-temperature (RT) magnetoresistance (MR) in a novel Fe-based perovskite, SrVFeO. This compound contains ordered oxygen vacancies in every fifth primitive perovskite (111) plane, leading to a layered structure consisting of triple-octahedral and double-tetrahedral layers. Along with the oxygen vacancies, the transition-metal ions are also ordered: the octahedral sites are occupied by 100% of Fe ions, while the tetrahedral sites are occupied by 25% of Fe ions and 75% of V ions.

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Purpose: Radical gastrectomy is considered the first choice of curative treatment for older patients with gastric cancer (GC). However, there is limited data on the survival benefits of gastrectomy for older patients with GC.

Methods: This was a retrospective observational study where medical records of patients aged ≥ 75 years with clinically resectable primary GC, comprising 115 patients who underwent radical surgery (S group) and 33 patients who received conservative therapy (non-S group) (total cohort) and 44 propensity-matched patients (matched cohort), were reviewed.

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Narrow-gap semiconductors with visible light absorption capability have attracted attention as photofunctional materials. H-doped BaSnYO containing Sn(II) species was recently reported to absorb visible light up to 600 nm, which represents the first demonstration of oxyhydride-based visible-light-absorbers. In the present study, a more detailed investigation was made to obtain information on the synthesis and properties of H-doped perovskite-type stannate with respect to the A-site cation of the material and the preparation conditions.

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Luciferases have been widely utilized as sensitive reporters to monitor gene expression and protein-protein interactions. Compared to firefly luciferase (Fluc), a recently developed luciferase, Nanoluciferase (NanoLuc or Nluc), has several superior properties such as a smaller size and stronger luminescence activity. We compared the reporter properties of Nluc and Fluc in rice ().

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Background: Percutaneous transhepatic gallbladder drainage (PTGBD) is recommended for acute cholecystitis patients at high risk for surgical treatment. However, there is no evidence about the best timing of surgery after PTGBD. Here, we retrospectively investigated the influence of the interval between PTGBD and surgery on perioperative outcomes and examined the optimal timing of surgery after PTGBD.

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Background: Intra-abdominal desmoid-type fibromatosis (DF) rarely necessitates emergency surgery. However, the condition is difficult to diagnose preoperatively and can become life-threatening if left untreated.

Case Report: A 46-year-old man complained of fever and right lower quadrant pain.

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Background: In the fight against the pandemic of COVID-19, it is important to ascertain the status and trend of the infection spread quickly and accurately.

Objective: The purpose of our study is to formulate a new and simple indicator that represents the COVID-19 spread rate by using publicly available data.

Methods: The new indicator K is a backward difference approximation of the logarithmic derivative of the cumulative number of cases with a time interval of 7 days.

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The ΩΩ system in the ^{1}S_{0} channel (the most strange dibaryon) is studied on the basis of the (2+1)-flavor lattice QCD simulations with a large volume (8.1  fm)^{3} and nearly physical pion mass m_{π}≃146  MeV at a lattice spacing of a≃0.0846  fm.

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The possible exotic meson Z_{c}(3900), found in e^{+}e^{-} reactions, is studied by the method of coupled-channel scattering in lattice QCD. The interactions among πJ/ψ, ρη_{c}, and D[over ¯]D^{*} channels are derived from (2+1)-flavor QCD simulations at m_{π}=410-700  MeV. The interactions are dominated by the off-diagonal πJ/ψ-D[over ¯]D^{*} and ρη_{c}-D[over ¯]D^{*} couplings, which indicates that the Z_{c}(3900) is not a usual resonance but a threshold cusp.

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A 79-year-old man complaining of an anterior chest mass with pain had an abnormal shadow on chest X-ray. A mass, 7 cm in size, with destruction of the right 4th rib was found on chest computed tomography. A F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) corresponding to the lesion showed an abnormal accumulation of FDG with the standardized uptake value(SUV) max=16.

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We report a case of pulmonary cryptococcosis suspected of lung cancer. A 65-year-old woman had an abnormal shadow on chest X-ray. A solitary nodule, 12 mm in size, with pleural indentation and spicula in S3 of the left lung was found on chest computed tomography.

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A 63-year-old woman underwent a low anterior resection for rectal cancer in 2002.A n anastomotic recurrence was diagnosed in July 2011.S he rejected the possibility of colostomy as radical surgery.

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Quark mass dependence of the equation of state (EOS) for nucleonic matter is investigated, on the basis of the Brueckner-Hartree-Fock method with the nucleon-nucleon interaction extracted from lattice QCD simulations. We observe saturation of nuclear matter at the lightest available quark mass corresponding to the pseudoscalar meson mass ≃469  MeV. Mass-radius relation of the neutron stars is also studied with the EOS for neutron-star matter from the same nuclear force in lattice QCD.

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We have performed precise dc magnetization measurements for a single crystal of UBe(13) down to 0.14 K, up to 80 kOe. We observed a magnetic anomaly in the superconducting (SC) mixed state at a field, named H(Mag)(*) (~ 26 kOe, at 0.

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