Publications by authors named "Yoshikawa I"

Thanks to recent developments in spectrophotometric instruments, the spectra, quantum yields (Φ), and lifetimes () of photoluminescence from organic and inorganic compounds can be readily determined not only in solution but also in the solid state. It is known that naphthalene emits fluorescence in solution, but not in the solid state. In a previous paper, we reported that solid-state emission can be seen from biaryl compounds comprised of chromophores that show no emission in the solid state.

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The chiral amine catalyzed diastereo- and enantioselective [3 + 2] cycloaddition between isatin-derived azomethine ylides and α,β-unsaturated aldehydes was successfully carried out to afford spiro[oxindole-3,2'-pyrrolidine]s. It was anticipated that the formation of azomethine ylides occurred the cycloreversion of dispirooxindole-imidazolidines, which are precursor imine homodimers, in aqueous solvents.

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In the processing of polymer blends and composites, in-line near-infrared (NIR) spectroscopy enables monitoring of the composition and its composite uniformity and contributes to rapid process development and quality control. However, in the injection molding process, the study of the composition of polymer materials has been delayed due to high-pressure conditions. Our research group developed NIR probes for transmission and diffuse reflectance measurements that can withstand high-pressure and temperature conditions up to 130 MPa and 200 °C.

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Article Synopsis
  • The Comet Interceptor mission aims to explore a long-period comet or an interstellar object entering our Solar System, with a focus on its surface composition, shape, and the composition of its gas and dust.
  • Proposed to the European Space Agency in 2018 and approved in June 2022, it is set to launch in 2029 alongside the Ariel mission, utilizing a low-cost approach that allows it to wait for a suitable target comet.
  • The mission will feature a main probe and two sub-probes (B1 from JAXA and B2), providing simultaneous, detailed 3D information about the comet and its interaction with the solar wind, making it unique compared to previous missions.
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A 68-year-old man developed immune-related adverse event (irAE) colitis after the initiation of nivolumab and ipilimumab combination therapy for malignant melanoma. We diagnosed the patient with grade 3 irAE colitis and started prednisolone (1 mg/kg/day). Although the symptom improved once, it worsened along with the tapering of prednisolone.

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A photoinduced crystal-to-liquid transition (PCLT) behavior of new acylhydrazone derivatives (NCs) is reported. The photoswitching of the NCs was identified as a negative photochromism with a high -to- conversion yield (>98%). A kinetic analysis shows a half-life of almost one month.

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Plant secondary metabolites exhibit various horticultural traits. Simple and rapid analysis methods for evaluating these metabolites are in demand in breeding and consumer markets dealing with horticultural crops. We applied probe electrospray ionization (PESI) to evaluate secondary metabolite levels in horticultural crops.

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  • Dust storms on Mars help move water from the lower atmosphere to the upper atmosphere, which affects the escape of hydrogen and oxygen.
  • During a significant dust storm, observations showed that hydrogen levels in the upper atmosphere rise, while oxygen levels temporarily fall due to factors like water ice absorption.
  • The interplay of atmospheric waves and dust affects the transportation of these elements, suggesting that if this pattern continues, Mars could have a more oxidized atmosphere with implications for its water loss history and potential habitability.
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A 70-year-old man was referred to our department for the treatment of early gastric cancer. Contrast-enhanced computed tomography (CT) incidentally showed diffuse enlargement of the pancreas with a capsule-like rim, and blood tests showed elevated serum IgG4 levels, leading to a diagnosis of autoimmune pancreatitis (AIP). Endoscopic treatment for gastric cancer was performed, and pathological findings showed adenocarcinoma with abundant IgG4-positive plasma cell infiltration.

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Three polymorphs of salicylideneaniline (SA) were prepared, and their photochromic behavior was examined using a recently developed single-crystal microscopic UV-vis spectroscopy approach. This system enabled us to acquire absorption data during the bleaching process as a function of temperature and visible light intensity. First, we demonstrated that, in contrast to the generally accepted assumption, the bleaching curves were notably influenced by the degree of photosaturation at the initial stage.

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Salicylideneaniline (SA) was found to exhibit extraordinary long-life photochromism upon being included in a cavity of guanidinium organosulfonate and exhibited a lifetime of ∼30 times that of a pure SA crystal. Crystal structure analysis suggested that the sulfonate molecule in the apo-host provided a flexible cavity space that kinetically trapped SA in its photo-isomerized form, as if it was locked by a ratchet-like mechanism.

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The cold crystallization mechanism of 1-{[4'-(4″-nitrophenylazo)phenyloxy]}hexyl-3-methyl-1-imidazol-3-ium tetrafluoroborate ionic liquid crystal was investigated based on thermal analysis, structural analysis, infrared spectroscopy, and quantum chemical calculations. By conducting thorough structural characterization, we found that the prerequisite for cold crystallization is the irreversible molecular conformational alteration induced by the initial heating of the as-grown crystal into a smectic liquid crystal. The originally linear cation molecule bends and forms a step-stair conformation that persists throughout the subsequent heating and cooling processes as phase transition occurs from the crystal phase to the liquid crystal phase and then to the isotropic liquid phase.

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Sugar content is one of the most important quality traits of tomato. Cell wall invertase promotes sucrose unloading in the fruit by maintaining a gradient of sucrose concentration between source leaves and fruits, while invertase inhibitor (INVINH) regulates this process. In this study, knock-out of cell wall INVINH in tomato (SlINVINH1) was performed by genome editing using, CRISPR/Cas9 and Target-AID technologies.

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Article Synopsis
  • The study focused on evaluating the response rates of adalimumab (ADA) for treating ulcerative colitis (UC) in patients who didn't respond to other treatments.
  • Out of 35 patients, the clinical response rates were 60% at 8 weeks and 51.4% at 52 weeks, with remission rates of 45.7% and 48.6%, respectively.
  • Positive predictors for better outcomes included the combination of ADA with immunomodulators and achieving a lower partial Mayo score at 8 weeks, indicating potential indicators for successful long-term treatment.
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Background/purpose: Recurrent biliary obstruction (RBO) after self-expandable metallic stent (SEMS) insertion is a big problem in patients with unresectable malignant biliary obstruction (MBO). Sarcopenia is associated with poor prognosis in patients with malignancies. The purpose of this study is to clarify the relationship between RBO and sarcopenia.

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A 13-year-old boy was admitted to our hospital because of bloody stools. Although a Meckel's diverticulum (MD) was suspected, capsule endoscopy (CE) revealed no remarkable findings. Seven months later, he was admitted again because of rebleeding.

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Chromism-color changes by external stimuli-has been intensively studied to develop smart materials because of easily detectability of the stimuli by eye or common spectroscopy as color changes. Luminescent chromism has particularly attracted research interest because of its high sensitivity. The color changes typically proceed in a one-way, two-state cycle, i.

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Objectives: Esophageal variceal bleeding can be fatal in patients with liver cirrhosis. The aim of this study was to investigate the relationship between gastroesophageal flap valve (GEFV) and esophageal variceal bleeding.

Methods: Subjects were cirrhotic patients with endoscopically diagnosed esophageal varices treated at our hospital between 2005 and 2019, excluding those with F3 form and red color (RC) signs at first endoscopy.

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  • The study aims to evaluate different diagnostic methods for detecting Clostridioides difficile infection (CDI) in patients with significant diarrhea across 12 medical facilities in Japan, comparing them to the gold standard of toxigenic culture (TC).
  • Key findings indicated that nucleic acid amplification tests (NAAT) showed higher sensitivity (74%) compared to enzyme immunoassays (EIA) (41%) and performed similarly to the GDH algorithm (71%).
  • Overall, NAAT and the GDH algorithm demonstrated good negative predictive values (92% and 91%, respectively) but highlighted the complexity of choosing the optimal diagnostic approach amid varying performance metrics for CDI detection.
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A 61-year-old man received an esophagogastroduodenoscopy for further investigation of mesenteric lymphadenopathy. Esophagogastroduodenoscopy revealed swollen gastric folds and cobble stone mucosa in the gastric body. Magnifying endoscopy with narrow-band imaging showed branched abnormal vessels and the absence or destruction of gastric pits.

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Imidazo[1,2- a]pyridine derivatives with different hydroxyaryl units (1-3), which could potentially form an intramolecular hydrogen-bonded seven-membered ring in either a planar or a twisted conformation, were newly developed, and the effect of conformation and steric repulsion on the excited-state intramolecular proton transfer (ESIPT) luminescence was evaluated. Among them, 1 and 2 formed an intramolecular hydrogen-bonded seven-membered ring in the crystalline state and exhibited efficient ESIPT luminescence in the solid state (quantum yield up to 0.45).

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Background: Determining the depth of invasion is important when considering therapeutic strategies for early gastric cancer (EGC). We determined the effects of learning the non-extension sign, that is, an index of T1b2 in EGC, on identifying its depth of invasion.

Methods: Endoscopic images of 40 EGC cases (20 showing positive non-extension sign on endoscopy as T1b2 and 20 showing negative non-extension sign on endoscopy as T1a-T1b1) were randomly displayed on PowerPoint.

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Clostridioides (Clostridium) difficile is the leading cause of healthcare-associated infectious diarrhea in the developed world. Retrospective studies have shown a lower incidence of C. difficile infection (CDI) in Japan than in Europe or North America.

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Objectives: The pathological diagnosis of endoscopically resected early gastric cancer (EGC) is performed by evaluating a few representative sections from the specimen. We aimed to determine whether evaluating twice as many sections as usual by essentially cutting the original sections in half could improve the pathological diagnosis of EGC.

Methods: We retrospectively investigated 85 EGC in 82 patients who had undergone endoscopic resection at our hospital from August 2008 to October 2012.

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Article Synopsis
  • - The study aimed to investigate whether a concurrent elemental diet (ED) improves outcomes for Crohn's disease patients already receiving anti-tumor necrosis factor-α (anti-TNF) therapy.
  • - A total of 72 Crohn's disease patients who responded to initial anti-TNF treatment were divided into two groups: one following the ED and the other not; the primary outcome measured was the remission rate after 2 years.
  • - Results showed no significant difference in cumulative remission rates between the ED group (60.9%) and the non-ED group (56.7%), suggesting that the addition of ED did not enhance treatment outcomes for these patients.
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