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81.
82.
Jun Yoshinaga Naoto Matsuo Hideki Imai Minato Nakazawa Tsuguyoshi Suzuki Masatoshi Morita 《International journal of environmental analytical chemistry》2013,93(1-2):27-38
Abstract Elemental concentrations of internal organs (cerebrum, cerebellum, heart, spleen, liver and kidney) of Japanese were measured with inductively coupled plasma mass spectrometry (ICP-MS). Sixty-one elements were determined simultaneously, and concentrations of some trace elements in human organs, on which information are scarcely available in the literature, were obtained. The analytical values obtained by ICP-MS and those by other methods were compared and fairly good agreement was found for Cd, Zn and Fe. Moderate agreement was found for Se and Hg, but discrepancy was observed for Mg and Na. Unacceptable values were obtained for some elements, such as Ti, Sc or Ge, probably due to polyatomic molecular interference. 相似文献
83.
Malcolm S. Cole Michael D. Howe Dr. Joseph A. Buonomo Dr. Sachin Sharma Dr. Elise A. Lamont Scott I. Brody Dr. Neeraj K. Mishra Dr. Yusuke Minato Dr. Joshua M. Thiede Dr. Anthony D. Baughn Dr. Courtney C. Aldrich 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(51):e202200995
Tuberculosis (TB) is a leading source of infectious disease mortality globally. Antibiotic-resistant strains comprise an estimated 10 % of new TB cases and present an urgent need for novel therapeutics. β-lactam antibiotics have traditionally been ineffective against M. tuberculosis (Mtb), the causative agent of TB, due to the organism's inherent expression of β-lactamases that destroy the electrophilic β-lactam warhead. We have developed novel β-lactam conjugates, which exploit this inherent β-lactamase activity to achieve selective release of pyrazinoic acid (POA), the active form of a first-line TB drug. These conjugates are selectively active against M. tuberculosis and related mycobacteria, and activity is retained or even potentiated in multiple resistant strains and models. Preliminary mechanistic investigations suggest that both the POA “warhead” as well as the β-lactam “promoiety” contribute to the observed activity, demonstrating a codrug strategy with important implications for future TB therapy. 相似文献
84.
Nobuko Yoshimoto Osamu Shimamura Takuya Nishimura Minato Egashira Maiko Nishioka Masayuki Morita 《Electrochemistry communications》2009,11(2):481-483
A novel polymeric electrolyte based on a self-assembled copolymer moiety has been prepared by a simple method of photo-induced radical polymerization of a mixture consisting of stearylmethacrylate (SMA) and poly(ethylene glycol)-monomethacrylate (PEM) that dissolves LiBF4 as the electrolytic salt. The SMA moiety work as mechanically stable backbone and the PEM unit dissolving the salts serves as ion-conducting path in the polymeric composite. Solid-state NMR measurements indicated that the resulting polymer composite consists of PEM-rich and SMA-rich phases, each of which exists within several nanometers apart. The ionic conductivity of the polymer electrolyte with the composition of PEM/SMA = 7/3 (by mass ratio) was 2.8 × 10?5 S cm?1 at 50 °C, which was significantly higher than that of the polymer electrolyte based on cross-linked PEM copolymer without SMA. 相似文献
85.
Kenjiro Ogawa 《Discrete Mathematics》2010,310(22):3276-3277
For a poset P=(X,≤), the upper bound graph (UB-graph) of P is the graph U=(X,EU), where uv∈EU if and only if u≠v and there exists m∈X such that u,v≤m. For a graph G, the distance two graph DS2(G) is the graph with vertex set V(DS2(G))=V(G) and u,v∈V(DS2(G)) are adjacent if and only if dG(u,v)=2. In this paper, we deal with distance two graphs of upper bound graphs. We obtain a characterization of distance two graphs of split upper bound graphs. 相似文献
86.
87.
Keiko Takahashi Kenjiro Hattori 《Journal of inclusion phenomena and macrocyclic chemistry》1984,2(3-4):661-667
Tosylation of -cyclodextrin in an aqueous alkaline solution gave two regiospecific isomers (2-monotosyl--cyclodextrin(1) and 6-monotosyl--cyclodextrin(2)), that could recognize and catalyze small sized guest molecules; 2-monotosyl--CD recognized small sized guest molecules more effectively than did 6-monotosyl--CD. 相似文献
88.
Junko Okamoto Shinichi Yamabe Tsutomu Minato Toshio Hasegawa Takahisa Machiguchi 《Helvetica chimica acta》2005,88(6):1519-1539
Tropone ( 1 ) reacts with ketenes 2 to yield [8+2] cycloadducts, the γ‐lactones 3 . The concerted [8+2] cycloaddition path is formally symmetry‐allowed, but we established that it is unfavorable. Careful low‐temperature NMR (1H, 13C, and 19F) spectroscopies of the reaction of diphenyl ketene ( 2b ) or bis(trifluoromethyl) ketene ( 2c ) with tropone ( 1 ) allowed the direct detection of a β‐lactone intermediates 5b , c and novel norcaradiene species 6b , c in head‐to‐head configurations. The [2+2] cycloadducts 5b , c equilibrated with the norcaradienes 6b , c . The β‐lactones 5b and 5c were converted to the γ‐lactones 3b and 3c , respectively, in quantitative yields. The DFT calculations showed that the concerted [8+2] cycloaddition is unfavorable. The first step of the calculated reaction 1 + 2c is a cycloaddition which leads to a dioxetane intermediate. This initial [2+2] cycloadduct is isomerized to the β‐lactone 5c via the first zwitterionic intermediate. The β‐lactone 5c is further isomerized to the product γ‐lactone 3c via the second zwitterion intermediate. Thus, 3c is not formed via the well‐established two‐step mechanism including zwitterionic intermediates but via a five‐step mechanism composed of a [2+2] cycloaddition and subsequent isomerization (Scheme 12). 相似文献
89.
Yukio Isobe Kenjiro Onimura Hiromori Tsutsumi Tsutomu Oishi 《Journal of polymer science. Part A, Polymer chemistry》2001,39(20):3556-3565
Asymmetric anionic homopolymerizations of N‐1‐naphthylmaleimide (1‐NMI) were performed with chiral ligand/organometal complexes to form optically active polymers. Poly(1‐NMI)s obtained with methylene‐bridged bisoxazoline derivatives (Rbox)‐diethylzinc (Et2Zn) complexes showed high specific optical rotations ([α]) from +152.3 to +191.4°. Circular dichroism spectra of the polymers exhibited a split Cotton effect in the UV absorption‐band region. According to the exciton chirality method, the absolute configuration of the polymer main chain was determined according to the following method: (+)‐poly[N‐substituted maleimides (RMI)] main chains can contain more (S,S)‐ than (R,R)‐configurations. (?)‐Poly(RMI) main chains can contain more (R,R)‐ than (S,S)‐configurations. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3556–3565, 2001 相似文献
90.
Makoto Minato Susumu Hiratsuka Takashi Ito 《Journal of organometallic chemistry》2004,689(6):1025-1028
The reaction of Cp2MoH2 (Cp=η5-C5H5) with homoallyl alcohol in the presence of a protonic acid afforded a cationic η3-crotyl molybdenum complex and a cyclic α-methyl-γ-hydroxypropyl molybdenum complex. This reaction proceeds via the stepwise formation of the cyclic complex, followed by formation of the η3-crotyl complex. 相似文献