128 research outputs found

    NHC-catalyzed cleavage of vicinal diketones and triketones followed by insertion of enones and ynones

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    Thiazolium carbene-catalyzed reactions of 1,2-diketones and 1,2,3-triketones with enones and ynones have been investigated. The diketones gave α,β-double acylation products via unique Breslow intermediates isolable as acid salts, whereas the triketones formed stable adducts with the NHC instead of the coupling products

    Machinability of SMART Forging Process Materials in Intermittent Cutting: 2nd Report : Machinability in Normal Cutting Region and Selection of Optimum Cutting Condition

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    Transmission used in automobiles is indispensable from the viewpoint of improvement of maximum speed, quietness and fuel consumption even if the power source of automobile is changed from internal combustion engine to electric motor in the future. We are studying a heat treatment process for imparting machinability to the forged material after hot forging used for a transmission of automobiles. In the past, the heat stored in the material after hot forging was merely released into the atmosphere. We succeeded in imparting machinability to the material by cooling while well controlling the heat stored in the forged material after hot forging. In the previous paper [1], we reported the progress of tool wear of this forged material in the high-speed cutting region with the cutting speed of 200 m/min or more in intermittent cutting. In this report, we conducted cutting experiments on the machinability of this developed forged material in the normal cutting speed region with the cutting speed less than 200 m/min. As a result, at the cutting speed V of V=157 m/min or less, it reached the conclusion that the built-up edges frequently occurred and the tool was chipped due to it. From the previous report and the results of this experiment, it was found that the cutting speed V of about V=213 m/min is optimum for cutting these forged materials with cemented carbide

    NHC-catalyzed cleavage of vicinal diketones and triketones followed by insertion of enones and ynones

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    Thiazolium carbene-catalyzed reactions of 1,2-diketones and 1,2,3-triketones with enones and ynones have been investigated. The diketones gave α,β-double acylation products via unique Breslow intermediates isolable as acid salts, whereas the triketones formed stable adducts with the NHC instead of the coupling products

    Benzothiazolylphenol–Substituted Ketoester is a Useful Fluorescent Probe for Detection of the Mitochondrion in Sea Urchin Sperm

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    One of the ketoesters derived from benzothiazolylphenol-substituted dioxetane,benzothiazolylphenol-substituted ketoester (TPKE), demonstrates fluorescence in a 0.1 MNaOH 1). In this study, the fluorescent staining of a living cell with TPKE was demonstratedby fluorescence microscopy. When sperm from two species of sea urchins—Pseudocentrotusdepressus and Anthocidaris crassispina—were used as biological materials, TPKE showed afluorescent signal in the midpiece that was composed of a single mitochondrion. The ratioof fluorescent signal intensity to background noise (S/N) was high in the sperm stained with1.0–5.0 μg/ml TPKE in normal artificial seawater (pH 8.0). The S/N ratio decreased inacidic seawater (pH 6.0); acidic conditions repress respiratory activity in sea urchin sperm.Moreover, in the presence of the respiratory chain inhibitor antimycin A and the uncouplercarbonyl cyanide p--trifluoromethoxyphenyl-hydrazone, the sperm showed faint or nofluorescence in normal artificial seawater (pH 8.0). Sea urchin sperm stained with TPKEafter fixation showed faint or no fluorescence. These results suggest that TPKE is apotential fluorescent probe of living sea urchin sperm mitochondria with high respiratoryactivities

    Clostridium butyricum MIYAIRI 588 contributes to the maintenance of intestinal microbiota diversity early after haematopoietic cell transplantation

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    Fukushima K., Kudo H., Oka K., et al. Clostridium butyricum MIYAIRI 588 contributes to the maintenance of intestinal microbiota diversity early after haematopoietic cell transplantation. Bone Marrow Transplantation , (2024); https://doi.org/10.1038/s41409-024-02250-1.In patients undergoing haematopoietic stem-cell transplantation (HSCT), the intestinal microbiota plays an important role in prognosis, transplant outcome, and complications such as graft-versus-host disease (GVHD). Our prior research revealed that patients undergoing HSCT substantially differed from healthy controls. In this retrospective study, we showed that administering Clostridium butyricum MIYAIRI 588 (CBM588) as a live biotherapeutic agent is associated with maintaining intestinal microbiota in the early post-HSCT period. Alpha diversity, which reflects species richness, declined considerably in patients who did not receive CBM588, whereas it remained consistent in those who received CBM588. In addition, β-diversity analysis revealed that CBM588 did not alter the gut microbiota structure at 7–21 days post-HSCT. Patients who developed GVHD showed structural changes in their microbiota from the pre-transplant period, which was noticeable on day 14 before developing GVHD. Enterococcus was significantly prevalent in patients with GVHD after HSCT, and the population of Bacteroides was maintained from the pre-HSCT period through to the post-HSCT period. Patients who received CBM588 exhibited a contrasting trend, with lower relative abundances of both genera Enterococcus and Bacteroides. These results suggest that preoperative treatment with CBM588 could potentially be beneficial in maintaining intestinal microbiota balance
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