Publications by authors named "Chihiro Maeda"

Intramolecular aromatic oxidative coupling of 3,6-bis(m-terphenyl-2'-yl)carbazole provided a bis(m-terphenyl)-fused carbazole, while that of 3,6-bis(m-terphenyl-2'-yl)-1,8-diphenylcarbazole afforded a bis(quaterphenyl)-fused carbazole. Borylation of the latter furnished a B,N-embedded helical nanographene binding a fluoride anion via a structural change from the three-coordinate boron to the four-coordinate boron. The anionic charge derived from the fluoride anion is stabilized over the expanded p-framework, which leads to the high binding constant (Ka) of 1 × 105 M-1.

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Although helicenes are promising molecules, the synthetic difficulty and tediousness have often been problems, and only small amounts of optically pure helicenes have been obtained by using chiral HPLC in most cases. Herein, aza[7]helicenes or closed-aza[7]helicenes with (1R)-menthyl substituents were selectively synthesized via the intramolecular Scholl reaction, and the diastereomeric pairs were separated by silica gel column chromatography. The optically pure helicenes were further transformed into the corresponding cyclic dimers, and the chiroptical properties were investigated.

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Brain aging causes a wide variety of changes at the molecular and cellular levels, leading to the decline of cognitive functions and increased vulnerability to neurodegenerative disorders. The research aimed at understanding the aging of the brain has made much progress in recent decades. Technological innovations such as single-cell RNA-sequencing (scRNA-seq), proteomic analyses, and spatial transcriptomic analyses have facilitated the research on the dynamic changes occurring within neurons, glia, and other cells along with their impacts on intercellular communication during aging.

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Article Synopsis
  • The "fix followed by flap" protocol is used for Gustilo type IIIB open fractures when immediate "fix and flap" surgery isn't feasible due to patient conditions or scheduling challenges.* -
  • A review of 10 cases treated with this method showed successful outcomes, including all free flaps surviving and no deep infections occurring post-surgery.* -
  • The average time for fracture healing was 9.4 months, demonstrating that this approach is effective even with delayed flap coverage by specialized orthoplastic surgeons.*
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Oxidative fusion reaction of cyclic heteroaromatic pentads consisting of pyrrole and thiophene gave closed-heterohelicene monomers and dimers depending on the oxidation conditions. Specifically, oxidation with [bis(trifluoroacetoxy)iodo]benzene (PIFA) gave closed-[7]helicene dimers connected at the β-position of one of the pyrrole units with remarkably elongated C-C bonds of about 1.60 Å.

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Background: Personalized treatment for non-small cell lung cancer (NSCLC) has advanced rapidly, and elucidating the genetic changes that trigger this disease is crucial for appropriate treatment selection. Both slow-pull and aspiration methods of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) are accepted methods for collecting samples suitable for next-generation sequencing (NGS) to examine driver gene mutations and translocations in NSCLC. Here, we aimed to determine which of these two methods is superior for obtaining higher-quality samples from patients with NSCLC.

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Article Synopsis
  • Squamous cell carcinoma is less common in EGFR mutation-positive non-small cell lung cancers and responds poorly to early EGFR tyrosine kinase inhibitors compared to adenocarcinomas.
  • A study highlighted a 57-year-old male with stage IIIC squamous cell lung cancer who had both an exon19 deletion and a T790M mutation identified through genetic testing.
  • The patient was treated with osimertinib after other treatments failed, achieving a partial response that lasted over 20 months, suggesting that accurate genetic testing can help predict the effectiveness of EGFR-TKIs.
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Background: Based on the results of the PACIFIC trial, maintenance with durvalumab has emerged as the standard treatment following concurrent chemoradiotherapy in patients with unresectable locally advanced non-small cell lung carcinoma (NSCLC). However, adverse events attributed to durvalumab, especially lung injuries, including immune-related adverse events, and radiation pneumonitis, are concerning. This study retrospectively investigated the factors related to lung injury in patients receiving the PACIFIC regimen.

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Chemical fixation of CO has received much attention. In particular, catalytic C-C bond formation with CO giving carboxylic acids is of great significance. Among the CO fixation methods, multiple carboxylation is one of the challenging subjects.

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Oxidation of dihydroxyhetero[7]helicenes gave dihetero[8]circulenes via the concomitant C-C coupling and dehydrative furan formation. The pristine dihetero[8]circulenes were synthesized in four steps and characterized for the first time. X-ray crystal structures and DFT-optimized structures revealed the distorted saddle-like structures, and the degree of the distortion was found to be correlated with the photophysical properties.

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Primary tracheal small-cell carcinoma is rare, and is often treated using small-cell lung cancer guidelines given that no standard treatment has been established for it. We report a patient in whom nodules appeared in the trachea and left main bronchus 11 months after surgery for pulmonary large-cell neuroendocrine carcinoma; a biopsy revealed small-cell carcinoma. Given the absence of malignant lesions elsewhere in the body, the lesions were diagnosed as primary tracheal small-cell carcinoma.

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Thymic neuroendocrine tumors associated with multiple endocrine neoplasia are only defined as carcinoid and are not associated with large-cell neuroendocrine carcinoma (LCNEC). We report the case of a multiple endocrine neoplasia type 1 patient with atypical carcinoid tumors with elevated mitotic counts (AC-h), an intermediate condition between carcinoid and LCNEC. A 27-year-old man underwent surgery for an anterior mediastinal mass and was diagnosed with thymic LCNEC.

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Circularly polarized luminescence (CPL) dyes are recognized to be new generation materials and have been actively developed. Molecular recognition systems provide nice approaches to novel CPL materials, such as stimuli-responsive switches and chemical sensing materials. CPL may be induced simply by mixing chiral or achiral, luminescent or nonluminescent host and guest; there are several combinations.

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Background: Clinically measurable factors affecting the progression-free survival (PFS) of patients receiving osimertinib as first-line therapy for epidermal growth factor receptor (EGFR) mutation-positive advanced non-small cell lung cancer (NSCLC) have not yet been established.

Methods: We retrospectively reviewed the medical records of 61 patients treated with osimertinib as primary therapy for EGFR mutation-positive advanced NSCLC at Yokohama City University Medical Center between August 2018 and March 2022. Our objective was to identify the independent predictors of PFS.

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Background/aim: Pulmonary enteric adeno-carcinoma (PEAC) is a rare type of non-small cell lung cancer (NSCLC), for which no established standard treatment exists. Combination therapy with the anti-programmed cell death protein 1 antibody pembrolizumab and platinum-containing chemotherapy is the standard treatment for NSCLC patients, but its effectiveness in PEAC is uncertain.

Case Report: We present a 68-year-old man with chemotherapy-naïve advanced PEAC who responded to a combination of pembrolizumab and platinum-containing chemotherapy.

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We recently reported that dietary cystine maintained plasma mercaptalbumin levels in rats fed low-protein diets. The present study aimed to compare the influence of low-protein diets supplemented with cystine and methionine, which is another sulfur amino acid, on plasma mercaptalbumin levels in rats. Male Sprague-Dawley rats were fed a 20% soy protein isolate diet (control group), 5% soy protein isolate diet (low-protein group) or 5% soy protein isolate diet supplemented with either methionine (low-protein + Met group) or cystine (low-protein + Cyss group) for 1 week.

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Carbazole-based aza[7]helicenes and hetero[9]helicenes were successfully obtained via the intramolecular Scholl reaction of 3,6-bis(biphenyl-2-yl)carbazole congeners, while the reaction of 3,6-bis(naphthylphenyl)-appended carbazole gave a triple helicene via an unexpected simultaneous double aryl rearrangement. DFT calculations suggested that the rearrangement proceeded via an arenium cation intermediate. In addition, the reaction of methoxy-appended substrate gave an azahepta[8]circulene via the concurrent C-C bond formation.

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Directly linked carbazole-based core-modified diporphyrin D2 and fused diporphyrin F2 were synthesized. These diporphyrins showed significant electronic interactions and conjugation allowing for redshifted near infrared (NIR) absorption and small HOMO-LUMO gaps as confirmed by NIR absorption spectroscopy, cyclic voltammetry (CV) measurements, and DFT calculations.

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Bifunctional Al porphyrins with quaternary ammonium halides, and , worked as excellent catalysts for the copolymerization of cyclohexene oxide (CHO) and CO at 120 °C. Turnover frequency (TOF) and turnover number (TON) reached 10 000 h and 55 000, respectively, and poly(cyclohexene carbonate) (PCHC) with molecular weight of up to 281 000 was obtained with a catalyst loading of 0.001 mol%.

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Hexameric and tetrameric porphyrin nanorings, · and ·, were synthesized in 53% and 14% yields, respectively, by the Sonogashira-type self-oligomerization of porphyrin monomer using hexadentate template and tetrapyridylporphyrin template . Template-free nanorings and were also prepared. The femtosecond transient absorption measurements revealed fast excitation energy hopping (EEH) along these nanorings with hopping rates of 2-5 ps.

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A variety of carbazolyl-appended Schiff bases were readily synthesized from 1-formylcarbazoles and aniline derivatives. Boron complexation of the resulting ligands allowed for facile preparation of new carbazole-based BODIPY analogues showing solid-state fluorescence. Furthermore, some dyes were converted into chiral compounds through the Et AlCl-mediated incorporation of a binaphthyl unit.

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Helical carbazole-based BODIPY analogues were readily synthesized via aza[7]helicenes. The structures of azahelicene-incorporated BF dyes were elucidated by x-ray diffraction analysis. DFT calculations revealed that the π-conjugated system expanded from the helicene moiety to the BODIPY framework.

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A series of carbazole-based boron dipyrromethenes (BODIPYs) 2 a-g bearing binaphthyl units have been synthesized by the Et AlCl-mediated reaction of the corresponding BODIPY difluorides 1 a-g with 1,1'-binaphthalene-2,2'-diol. Substituents such as halogen, nitrile, and amino groups were tolerated under the reaction conditions, and the reaction of the phenylethynyl-substituted 1 h gave (R,R)-3 h bearing two binaphthyl units. The chiroptical properties of these dyes with different substituents were investigated by UV/Vis, CD, fluorescence, and circularly polarized luminescence (CPL) spectroscopy.

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Peripheral π-expansion of carbazole-based porphyrins was achieved for the first time by the Pt-catalyzed cyclization and the incorporation of a benzocarbazole unit. These two types of fused porphyrins showed red-shifted and broad NIR absorption due to the expanded π-conjugation as confirmed by NIR absorption spectroscopy and DFT calculations.

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Chiral binaphthyl-strapped Zn(II) porphyrins with triazolium halide units were synthesized as bifunctional catalysts for kinetic resolution of epoxides with CO. Several catalysts were screened by changing the linker length and nucleophilic counteranions, and the optimized catalyst accelerated the enantioselective reaction at ambient temperature to produce optically active cyclic carbonates and epoxides.

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