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排序方式: 共有274条查询结果,搜索用时 46 毫秒
1.
Amphiphilic liquid‐crystalline 4‐miktoarm star copolymers with a siloxane junction leading to cylindrically nanostructured templates for a siloxane‐based nanodot array 下载免费PDF全文
Md Asadul Hoque Hideaki Komiyama Hiroki Nishiyama Keiji Nagai Takehiro Kawauchi Tomokazu Iyoda 《Journal of polymer science. Part A, Polymer chemistry》2016,54(9):1175-1188
Well‐defined A3B‐, A2B2‐, and AB3‐type 4‐miktoarm star copolymers (Mn = 10,500–16,200, Mw/Mn = 1.16–1.18) consisting of poly(ethylene oxide) (PEO) and polymethacrylate bearing an azobenzene mesogen (PMA(Az)) as the arms and cyclotetrasiloxane as the core unit were synthesized using a combined route composed of a thiol‐ene click reaction and atom transfer radical polymerization. Microphase‐separated structures of the star copolymers in thin films with a thickness of approximately 100 nm were investigated by GISAXS and TEM. The A3B‐type star‐(PEO)3[PMA(Az)]1 copolymer formed a more highly ordered PEO cylinder array with perpendicular alignment in the PMA(Az) matrix than that of the corresponding linear‐type block copolymer. The center‐to‐center distance of the PEO cylinders and the cylinder diameter were 13 and 4 nm, respectively. The highly ordered star‐(PEO)3[PMA(Az)]1 thin film was directly transferred to a siloxane‐based nanodot array by oxygen reactive ion etching. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1175–1188 相似文献
2.
Tsukiho Hayashi Ayumi Osawa Takehiro Watanabe Yoshiko Murata Atsushi Nakayama Kosuke Namba 《Tetrahedron letters》2017,58(20):1961-1964
1,3a,6a-Triazapentalene (TAP)-labeled enterobactin was developed as an iron ion sensor. 3-Acetylated-TAP was successfully introduced to the catechol ring of enterobactin, a well-recognized siderophore secreted by various Gram-negative bacteria. The fluorescence of TAP-labeled enterobactin decreased gradually as the amount of Fe3+ ion as an additive was increased, and 1.2 equiv of Fe3+ ion completely quenched the fluorescence. In clear contrast, when other metal ions were used, the fluorescence of TAP-labeled enterobactin remained even at 5.0 equiv. 相似文献
3.
Maria Helena Tirollo Taddei José Flávio Macacini Roberto Vicente Júlio Takehiro Marumo Luís Antônio Albiac Terremoto 《Journal of Radioanalytical and Nuclear Chemistry》2017,311(3):1687-1696
Nowadays, the scaling factor methodology is widely used in order to estimate the activity concentration of difficult to measure nuclides in low- and intermediate-level waste from nuclear reactors. However, very few experimental studies evaluate how operational changes in the reactors affect scaling factors. The present work examines the impact of operational changes on the scaling factors that were determined for spent ion-exchange resins and spent activated charcoal permanently withdrawn as radioactive wastes from the water cleanup system of the IEA-R1 nuclear research reactor. 相似文献
4.
Effect of Acid Treatment of Montmorillonite on “Support‐Activator” Performance to Support Metallocene for Propylene Polymerization Catalyst 下载免费PDF全文
Takao Tayano Hideshi Uchino Takehiro Sagae Katsuyuki Yokomizo Koji Nakayama Shigeki Ohta Hiroshi Nakano Masahide Murata 《大分子反应工程》2017,11(2)
This work is focused on montmorillonite (MMT)‐based “support‐activators” (S‐As) for the metallocene‐catalyzed propylene polymerization. This catalyst was previously industrialized; however, for further technological advances, the activation mechanism is investigated. The chemical and morphological requirements of the S‐A are surveyed using both commercially available raw clay minerals (non‐acid‐treated) and acid‐treated clay minerals. The S‐A possessing strong‐acid sites (pK a < ?8.2) gives a highly active catalyst. Acid treatment of MMT induces morphological changes as well as the formation of strong acid sites. Based on pore size distribution analysis and atomic force microscopy observations, it is concluded that the strong acid sites are located in the small pores around the edge of the clay mineral (not in the interlayer), where the structure is disordered by the acid treatment.
5.
Bumhee Lim Yangyang Cheng Takehiro Kato Anh-Tuan Pham Eliott Le Du Abhaya Kumar Mishra Elija Grinhagena Dimitri Moreau Naomi Sakai Jerome Waser Stefan Matile 《Helvetica chimica acta》2021,104(8):e2100085
Thiol-mediated uptake is emerging as method of choice to penetrate cells. This study focuses on irreversible covalent inhibitors of thiol-mediated uptake. High-content high-throughput screening of the so far largest collection of hypervalent iodine reagents affords inhibitors that are more than 250 times more active than Ellman’s reagent and rival the best dynamic covalent inhibitors. Comparison with other irreversible reagents reveals that inhibition within one series follows reactivity, whereas inhibition across series deviates from reactivity. These trends support that molecular recognition, besides dynamic covalent exchange, contributes significantly to thiol-mediated uptake. The most powerful inhibitors besides the best hypervalent iodine reagents were Fukuyama’s nosyl protecting group and super-cinnamaldehydes that have been introduced as irreversible activators of the pain receptor TRPA1. Considering that several viruses use different forms of thiol-mediated uptake to enter cells, the identification of new irreversible inhibitors of thiol-mediated uptake is of general interest for the discovery of new antivirals. 相似文献
6.
Prof. Joe Otsuki Takumi Okumura Dr. Kosuke Sugawa Dr. Shin-ichiro Kawano Prof. Kentaro Tanaka Dr. Takehiro Hirao Prof. Takeharu Haino Yu Jin Lee Seongsoo Kang Prof. Dongho Kim 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(12):4053-4063
Self-assembly of porphyrins is a fascinating topic, not only for mimicking chlorophyll assemblies in photosynthetic organisms, but also for the potential of creating molecular-level devices. Herein, zinc porphyrin derivatives bearing a meta-pyridyl group at the meso position were prepared and their assemblies studied in chloroform. Among the porphyrins studied, one with a carbamoylpyridyl moiety gave a distinct 1H NMR spectrum in CDCl3, which allowed the supramolecular structure in solution to be probed in detail. Ring-current-induced chemical-shift changes in the 1H NMR spectrum, together with vapor-pressure osmometry and diffusion-ordered NMR spectroscopy, among other evidence, suggested that the porphyrin molecules form a trimer with a triangular cone structure. Incorporation of a directly linked porphyrin–ferrocene dyad with the same assembling properties in the assemblies led to a rare example of a light-harvesting/charge-separation system in which an energy gradient is incorporated and reductive quenching occurs. 相似文献
7.
Akiko Hashimoto Takehiro Yamanaka Takeji Takamura-Enya 《Journal of nanoparticle research》2017,19(12):402
Fullerene is a well-known carbon nanomaterial, which can be potentially used for drug manufacture or delivery. Despite several successful examples of utilizing fullerene derivatives as drug candidate materials, their low water solubility under physiological conditions negatively affects the cell penetration efficiency after treatment. In this work, we successfully synthesized two fullerene derivatives with covalently attached fluorescein and boron dipyrromethene (BODIPY) fluorophore moieties, which exhibited cellular uptake and intracellular localization. While both fluorophores decreased their fluorescence intensity in the vicinity of fullerene, the cellar uptake of the fluorescein-modified fullerene was detected via fluorescence microscopy observations. Moreover, decreases in the fluorescence intensities of the intact fluorescein and BODIPY species were observed when both fluorophores and fullerene coexisted in aqueous media. 相似文献
8.
Drug-target networks have aided in many target prediction studies aiming at drug repurposing or the analysis of side effects. Conventional drug-target networks are bipartite. They contain two different types of nodes representing drugs and targets, respectively, and edges indicating pairwise drug-target interactions. In this work, we introduce a tripartite network consisting of drugs, other bioactive compounds, and targets from different sources. On the basis of analog relationships captured in the network and so-called neighbor targets of drugs, new drug targets can be inferred. The tripartite network was found to have a stable structure and simulated network growth was accompanied by a steady increase in assortativity, reflecting increasing correlation between degrees of connected nodes leading to even network connectivity. Local drug environments in the tripartite network typically contained neighbor targets and revealed interesting drug-compound-target relationships for further analysis. Candidate targets were prioritized. The tripartite network design extends standard drug-target networks and provides additional opportunities for drug target prediction. 相似文献
9.
Tetsuo Irifune Chiaki Ueda Shohei Ohshita Hiroaki Ohfuji Takehiro Kunimoto Toru Shinmei 《高压研究》2020,40(1):96-106
ABSTRACTNano-polycrystalline diamond (NPD) with various grain sizes has been synthesized from glassy carbon at pressures 15–25?GPa and temperatures 1700–2300°C using multianvil apparatus. The minimum temperature for the synthesis of pure NPD, below which a small amount of compressed graphite was formed, significantly increased with pressure from ~1700°C at 15?GPa to ~1900°C at 25?GPa. The NPD having grain sizes less than ~50?nm was synthesized at temperatures below ~2000°C at 15?GPa and ~2300°C at 25?GPa, above which significant grain growth was observed. The grain size of NPD decreases with increasing pressure and decreasing temperature, and the pure NPD with grain sizes less than 10?nm is obtained in a limited temperature range around 1800–2000°C, depending on pressure. The pure NPD from glassy carbon is highly transparent and exhibits a granular nano-texture, whose grain size is tunable by selecting adequate pressure and temperature conditions. 相似文献
10.
Fumihiro Gobo Takehiro Goto Tengfa Long Shu Yin Tsugio Sato 《Research on Chemical Intermediates》2011,37(2-5):211-217
Micro-disks and micro-rods of ZnO were successfully synthesized by a mild solution process using zinc chloride as starting material. The morphology of the ZnO crystals changed substantially, depending on the concentrations of the Zn2+ ion and organic additives in the solution. A plate-like Zn5(OH)8Cl2·H2O precursor with a layered structure could be produced in solutions with high concentrations of chloride ions. The thermal stability, including phase composition and morphology, of the as-prepared Zn5(OH)8Cl2·H2O in air and water was investigated. 相似文献