469 research outputs found

    Recent progress in the chemistry of heavy aromatics

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    The aromaticity and synthetic application of “heavy benzenes”, i.e., benzenes containing a heavier Group 14 element (Si, Ge, Sn, and Pb) in place of skeletal carbon, have been the targets of many theoretical and synthetic studies. Although the introduction of a sterically demanding substituent enabled us to synthesize and isolate heavy aromatic species as a stable compound by suppressing their high reactivity and tendency to polymerize, the existence of a protection group is an obstruction to the development of functional materials based on heavy aromatics. This review will delineate the most recent topics in the chemistry of heavy aromatics, i.e., the chemistry of “metallabenzenyl anions”, which are the heavier Group 14 element analogs of phenyl anions stabilized by taking advantage of charge repulsion instead of steric protection

    Equilibrium Behavior for Transition Metal Ionic Species in Liquid Phase Deposition Reaction

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    We tried to clarify to the deposition mechanism by applying the 11B and 19F NMR analyses to the LPD reaction solutions for the preparing titanium oxide films with various reaction conditions. Moreover, the optimum conditions of the syntheses of 3d transition metal oxide thin films were investigated by con-trolling pH and the concentration of reacting species. In the reaction of TiO2 deposition, TiF62- do not re-lease all F- ions, namely, the existence of hydrolysis intermediate species (TiFx(OH)y(H2O)6-x-y(4-x-y)) which could not be detected by 19F NMR because of the rapid ligand exchange in the LPD reaction solu-tions. In the reaction of Cr2O3 deposition, the optimization of the LPD reaction can be carried out by the controlling of the concentrations of reaction species and pH. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3522

    (E)-N-[2-(9-Fluorenyl­idene)-3a,5,7-tri­methyl-3,3a-dihydro-2H-indol-3-yl­idene]-2,4,6-trimethyl­aniline

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    The title compound, C33H30N2, has an E configuration at the imine double bond. The angle between the least-squares planes of the imine C=N—C group and the benzene ring of the 2,4,6-trimethylphenyl substituent is 85.38 (11)°. The crystal structure is sustained mainly by inter­molecular π–π inter­actions (3.510 Å) between the two fluorene rings and some C—H⋯π inter­actions

    9,9′-Dibromo-9,9′-bifluorene

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    9,9′-Dibromo-9,9′-bifluorene, C26H16Br2, has a gauche conformation about the connecting C—C bond [the Br—C—C—Br torsion angle is 59.39 (16)°]. The crystal structure is sustained mainly by an inter­molecular C—Br⋯π inter­action [3.299 (2) and 3.369 (2) Å] towards the bifluorene aromatic-ring-connecting C—C bond and a weak C—H⋯π inter­action (2.86 and 2.99 Å) between the two aromatic rings

    Soil-Pile Interaction in Vertical Vibration

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    This paper deals with the theoretical study concerning soil-pile interaction in vertical vibration for both the floating pile and the pile group. The analysis is made by applying the elastic wave theory to the viscoelastic layer overlying on the rigid bedrock. Further, the displacement responses of the pile and the complex stiffness at the pile head subjected to the harmonic excitation at the top of the pile are obtained for various parameters

    Destabilized Passivation Layer on Magnesium-Based Intermetallics as Potential Anode Active Materials for Magnesium Ion Batteries

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    Passivation of magnesium metal anode is one of the critical challenges for the development of magnesium batteries. Here we investigated the passivation process of an intermetallic anode: Mg3Bi2 synthesized by solid-state and thin film process. The Mg3Bi2 composite electrode shows excellent reversibility in magnesium bis(trifluoromethansulfonylamide) dissolved in acetonitrile, while Mg3Sb2, which has same crystal structure and similar chemical properties, is electrochemically inactive. We also fabricated the Mg3Bi2 thin film electrodes, which show reversibility with low overpotential not only in the acetonitrile solution but also glyme-based solutions. Surface layer corresponding to the decomposed TFSA anion is slightly suppressed in the case of the Mg3Bi2 thin film electrode, compared with Mg metal. Comparative study of hydrolysis process of the Mg3Bi2 and the Mg3Sb2 suggests that the both intermetallic anodes are not completely passivated. The bond valence sum mapping of the Mg3Bi2 indicates that the fast Mg2+ diffusion pathway between 2d tetrahedral sites is formed. The electrochemical properties of the Mg3Bi2 anode is mainly due to the less passivation surface with the fast Mg2+ diffusion pathways

    The effects of water and microstructure on the performance of polymer electrolyte fuel cells

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    n this paper, we present a comprehensive non-isothermal, one-dimensional model of the cathode side of a Polymer Electrolyte Fuel Cell. We explicitly include the catalyst layer, gas diffusion layer and the membrane. The catalyst layer and gas diffusion layer are characterized by several measurable microstructural parameters. We model all three phases of water, with a view to capturing the effect that each has on the performance of the cell. A comparison with experiment is presented, demonstrating excellent agreement, particularly with regard to the effects of water activity in the channels and how it impacts flooding and membrane hydration. We present several results pertaining to the effects of water on the current density (or cell voltage), demonstrating the role of micro-structure, liquid water removal from the channel, water activity, membrane and gas diffusion layer thickness and channel temperature. These results provide an indication of the changes that are required to achieve optimal performance through improved water management and MEA-component design. Moreover, with its level of detail, the model we develop forms an excellent basis for a multi-dimensional model of the entire membrane electrode assembly

    Discovery of Self‐Assembling Small Molecules as Vaccine Adjuvants

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    自己集合性ワクチンアジュバントの発見. 京都大学プレスリリース. 2020-10-07.Vaccine ingredients could be hiding in small molecule libraries. 京都大学プレスリリース. 2020-10-07.Immune potentiators, termed adjuvant, trigger early innate immune responses to ensure the generation of robust and long‐lasting adaptive immune responses of vaccines. Here we present study that takes advantage of a self‐assembling small molecule library for the development of a novel vaccine adjuvant. Cell‐based screening of the library and subsequent structural optimization led to the discovery of a simple, chemically tractable deoxycholate derivative (molecule 6 , also named cholicamide) whose well‐defined nano‐assembly potently elicits innate immune responses in macrophages and dendritic cells. Functional and mechanistic analyses indicate that the virus‐like assembly is engulfed inside cells and stimulates the innate immune response through toll‐like receptor 7 (TLR7), an endosomal TLR that detects single‐stranded viral RNA. As an influenza vaccine adjuvant in mice, molecule 6 was as potent as Alum, a clinically used adjuvant. The studies described here paves the way for a new approach to discovering and designing self‐assembling small‐molecule adjuvants against pathogens, including emerging viruses

    Impact of upgraded radiotherapy system on outcomes in postoperative head and neck squamous cell carcinoma patients

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    Background: This study was performed to evaluate the impact of upgrade of radiotherapy system, including launch of intensity-modulated radiation therapy (IMRT), on the therapeutic outcomes. Materials and methods: Patients with head and neck (H&N) squamous cell carcinoma (SCC) who underwent postoperative radiotherapy at our hospital between June 2009 and July 2019 were retrospectively reviewed. In July 2014, we converted the radiotherapy technique for these patients from a 3-dimensional conformal radiotherapy (3D-CRT) to IMRT, along with the adoption of a meticulous planning policy and a few advanced procedures, including online imaging guidance. Results: A total of 136 patients (57 treated with the previous system and 79 treated with the upgraded system) were reviewed. There were significantly more patients with extracapsular extension in the upgraded-system group than the previous-system group (p = 0.0021). There were significantly fewer patients with ≥ Grade 2 acute and late adverse events in the upgraded-system group than the previous-system group. The differences in progression-free survival (PFS), distant metastasis-free survival (DFFS), locoregional progression-free survival (LRPFS), and overall survival (OS) between the two groups were not statistically significant (p = 0.8962, 0.9926, 0.6244, and 0.4827, respectively). Multivariate analysis revealed that the upgrade had neither positive nor negative impact on survival outcomes. Extracapsular extension was independently associated with decreased LRPFS and OS (p = 0.0499 and 0.0392, respectively). Conclusions: The IMRT-centered upgrade was beneficial for the postoperative patients with H&N SCC, because survival outcomes were sustained with less toxicities.
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