281 research outputs found

    Glycosylation reactions mediated by hypervalent iodine : application to the synthesis of nucleosides and carbohydrates

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    To synthesize nucleoside and oligosaccharide derivatives, we often use a glycosylation reaction to form a glycoside bond. Coupling reactions between a nucleobase and a sugar donor in the former case, and the reaction between an acceptor and a sugar donor of in the latter are carried out in the presence of an appropriate activator. As an activator of the glycosylation, a combination of a Lewis acid catalyst and a hypervalent iodine was developed for synthesizing 4’-thionucleosides, which could be applied for the synthesis of 4’-selenonucleosides as well. The extension of hypervalent iodine-mediated glycosylation allowed us to couple a nucleobase with cyclic allylsilanes and glycal derivatives to yield carbocyclic nucleosides and 2’,3’-unsaturated nucleosides, respectively. In addition, the combination of hypervalent iodine and Lewis acid could be used for the glycosylation of glycals and thioglycosides to produce disaccharides. In this paper, we review the use of hypervalent iodine-mediated glycosylation reactions for the synthesis of nucleosides and oligosaccharide derivatives

    Low energy indium or gallium ion implantations to SiO2 thin films for development of novel catalysts

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    It has been demonstrated that indium (In) implanted silicon dioxide (SiO thin films catalyze a reaction of benzhydrol with acetylacetone. In this study, it is found that the threshold In ion incident energy for manifestation of the catalytic effect exists between 400 and 470 eV. Furthermore, a technique to implant gallium (Ga) to SiOfilms has been developed with highly controlled doses and injection energies for the formation of thin films that promote Ga catalysts. The efficiency of catalytic reactions by Ga implanted SiOthin films is yet to be improved. Unlike In implanted SiO2, the reason why no significant reaction was observed in the case of Ga implanted SiOfilms examined in this study seems that the Ga ion energy was so low that deposited surface Ga atoms should lack interactions with Si atoms for the manifestation of catalytic reaction. © 2014 The Surface Science Society of Japan.Satoru Yoshimura, Masato Kiuchi, Yoshihiro Nishimoto, Makoto Yasuda, Akio Baba, Satoshi Hamaguchi, Low Energy Indium or Gallium Ion Implantations to SiO2 Thin Films for Development of Novel Catalysts, e-Journal of Surface Science and Nanotechnology, 2014, Volume 12, Pages 197-202, Released April 26, 2014, Online ISSN 1348-0391, https://doi.org/10.1380/ejssnt.2014.197, https://www.jstage.jst.go.jp/article/ejssnt/12/0/12_197/_article/-char/e

    Prediction of pathologic node-negative clinical stage IA lung adenocarcinoma for optimal candidates undergoing sublobar resection

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    ObjectivePatients with pathologic node-negative early lung cancer may be optimal candidates for sublobar resection. We aimed to identify predictors of pathologic lymph node involvement in clinical stage IA lung adenocarcinoma.MethodsThe data from a multicenter database of 502 patients with completely resected clinical stage IA lung adenocarcinoma were retrospectively analyzed to determine the relationship between the lymph node metastasis status and tumor size on high-resolution computed tomography (HRCT) or maximum standardized uptake value (SUVmax) on [18F]-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (FDG-PET/CT). Revised SUVmax was used to correct interinstitutional discrepancies.ResultsIn multivariate analyses, either a solid tumor size on HRCT (P = .001) or an SUVmax on FDG-PET/CT (P = .049) was an independent predictor of lymph node metastasis. The predictive criteria of pathologic node-negative early lung cancer were a solid tumor size of less than 0.8 cm or an SUVmax of less than 1.5. Patients who met the predictive criteria of pathologic node-negative disease had less pathologic invasiveness, such as lymphatic, vascular, or pleural invasion (P < .001), and better disease-free survival (P < .0001) than those who did not, and 86 (40.4%) of the 213 patients with T1b (2-3 cm) tumors met the predictive criteria.ConclusionsEither a solid tumor size or an SUVmax was a significant independent predictor of nodal involvement in clinical stage IA lung adenocarcinoma. The pathologic node-negative status criteria of a solid tumor size of less than 0.8 cm on HRCT or an SUVmax of less than1.5 on FDG-PET/CT may be helpful for avoiding systematic lymphadenectomy for clinical stage IA lung adenocarcinoma, even in cases of T1b (2-3 cm) tumor

    Perfluorooctane Sulfonate (PFOS) and Related Perfluorinated Compounds in Human Maternal and Cord Blood Samples: Assessment of PFOS Exposure in a Susceptible Population during Pregnancy

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    Fluorinated organic compounds (FOCs), such as perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), and perfluorooctane sulfonylamide (PFOSA), are widely used in the manufacture of plastic, electronics, textile, and construction material in the apparel, leather, and upholstery industries. FOCs have been detected in human blood samples. Studies have indicated that FOCs may be detrimental to rodent development possibly by affecting thyroid hormone levels. In the present study, we determined the concentrations of FOCs in maternal and cord blood samples. Pregnant women 17–37 years of age were enrolled as subjects. FOCs in 15 pairs of maternal and cord blood samples were analyzed by liquid chromatography–electrospray mass spectrometry coupled with online extraction. The limits of quantification of PFOS, PFOA, and PFOSA in human plasma or serum were 0.5, 0.5, and 1.0 ng/mL, respectively. The method enables the precise determination of FOCs and can be applied to the detection of FOCs in human blood samples for monitoring human exposure. PFOS concentrations in maternal samples ranged from 4.9 to 17.6 ng/mL, whereas those in fetal samples ranged from 1.6 to 5.3 ng/mL. In contrast, PFOSA was not detected in fetal or maternal samples, whereas PFOA was detected only in maternal samples (range, < 0.5 to 2.3 ng/mL, 4 of 15). Our results revealed a high correlation between PFOS concentrations in maternal and cord blood (r(2) = 0.876). However, we did not find any significant correlations between PFOS concentration in maternal and cord blood samples and age bracket, birth weight, or levels of thyroid-stimulating hormone or free thyroxine. Our study revealed that human fetuses in Japan may be exposed to relatively high levels of FOCs. Further investigation is required to determine the postnatal effects of fetal exposure to FOCs

    Closure of multiple ventricular septal defects by the felt sandwich technique: Further analysis of 36 patients

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    ObjectivesWe previously described a novel technique for closure of trabecular ventricular septal defects by sandwiching the septum with 2 polyester felt patches without requiring left ventriculotomy. We describe the midterm results of this technique and the postoperative cardiac function.MethodsThis is a retrospective study of 36 consecutive patients. The median age and body weight at the time of repair was 15 months (range: 2-115 months) and 7.8 kg (range: 3.9-51.9 kg), respectively.ResultsSixty-three trabecular ventricular septal defects in 36 patients were closed with the felt sandwich technique. In the early postoperative period, 1 patient died of pulmonary hypertensive crisis. There were 2 late deaths. One patient died of pneumonia 6 months after surgery, and another died suddenly of ventricular arrhythmias 2 years after surgery. Three patients required reoperation (closure of major residual ventricular septal defect, cardiac transplantation for dilated cardiomyopathy, and pacemaker implantation for complete atrioventricular block). Postoperative left ventricular fractional shortening in the group with a body surface area less than 0.4 m2 was significantly lower than that in the group with a body surface area of 0.4 m2 or greater (0.22 ± 0.09 vs 0.31 ± 0.06, P = .0027). Moreover, there was a strong correlation between postoperative left ventricular ejection fraction and total patch area/body surface area ratio (R = −0.74, P = .0004).ConclusionMultiple trabecular ventricular septal defects can be closed with the felt sandwich technique easily and safely. Although this technique can be used in small infants, the use of numerous felt patches disturbs the movement of ventricular septum, which may cause postoperative cardiac dysfunction

    Critical contribution of MCL-1 in EMT-associated chemo-resistance in A549 non-small-cell lung cancer

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    Non-small cell lung cancer (NSCLC) is one of the leading causes of death in all lung cancer patients due to its metastatic spread. Even though cisplatin treatment after surgical resection of the primary tumor has been established as a standard chemotherapy for residual disease including metastatic spread, NSCLC often acquires a resistance against chemotherapy, and metastatic disease is often observed. Amongst many potential mechanisms, epithelial-to-mesenchymal transition (EMT) has been considered as an important process in acquiring both metastatic spread and chemo-resistance of NSCLC. In this study, we identified MCL-1 as a critical molecule for chemoresistance in A549 cells associated with TGF-β-induced EMT. Importantly, downregulation of MCL-1 by siRNA or inhibition of MCL-1 with pan-BCL2 inhibitor to inhibit MCL-1 was able to overcome the EMT-associated chemo-resistance in A549 cells. Collectively, MCL-1 can be a new therapeutic target for overcoming EMT-associated chemo-resistance in NSCLC patients in the context of post-operative chemotherapies

    微小地震の初期破壊過程

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    [研究概要

    Ⅲ.Chemistry

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    島根大学金沢大学大学院自然科学研究科 環境科学Editor : Tazaki, Kazue |田崎, 和
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