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121.
Yoshifumi Hanada Teizi Tanizaki Minoru Koga Hiroaki Shiraishi Mitsuyuki Soma 《Analytical sciences》2002,18(4):441-444
Liquid chromatography/mass spectrometry (LC/MS) has been applied to analyze N,N'-ethylenebisdithiocarbamate fungicides (EBDCs: manzeb, maneb and zineb) in environmental water samples. The EBDCs that are zinc and/or manganese salts are transformed into readily water-soluble sodium salts by adding an alkaline EDTA solution. The N,N'-ethylenebisdithiocarbamate anion is extracted into chloroform-hexane (3:1) as an ion pair with tetrabutylammonium, and then S-alkylated with methyl iodide. The extraction and derivatization are carried out at room temperature. The derivatized ethylenebisdithiocarbamic acid dimethyl ester is introduced into an LC/MS equipped with a negative ion electrospray ionization interface. Identification of the compound is performed with the specific quasi-molecular ion, and the quantitative analyses are carried out using the peak areas. The average recoveries and coefficients of variation of EBDCs at sub-ppb level are 79.1% and 29.3% (n = 6), respectively. The limit of detection based on standard deviation of 0.043 microg/L for manzeb is achieved. 相似文献
122.
Yoshifumi Takeda Nara 《Mathematische Nachrichten》1994,167(1):313-329
Let X be a nonsingular relatively minimal projective surface over an algebraically closed field of characteristic p > 0. We call X a false hyperelliptic surface if X satisfies the following conditions: (1) c2(X) = 0, c1(X)2 = 0, dim Alb (X) = 1, and (2) All fibres of the Albanese mapping of X are rational curves with only one cusp of type xpv + yn = 0. In this article, we consider a false hyperelliptic surface whose Albanese mapping has a cross-section. We prove that every false hyperellyptic surface with section arises from an elliptic ruled surface and that every false hyperelliptic surface has an elliptic fibration with multiple fibre. Moreover, we construct an example of false hyperelliptic surface with section, whose elliptic fibration has a multiple fibre of supersingular elliptic curve of multiplicity pv (v > 1). 相似文献
123.
124.
Kuniaki Nakagawa Toru Nakagawa Yoshifumi Ueda Kozo Kuchitsu 《Journal of Molecular Spectroscopy》1976,63(3):547-552
Laser Stark spectra of carbonyl sulfide have been measured with parallel and perpendicular polarization of a 9.4 μm band CO2 laser with the Stark field up to 90 kV/cm. Components of the P(2) and R(1) transitions of the 0310–0110 band and those of the P(1) transition of the 0400–0200 band for 16O12C32S have been analyzed. Band origins, 1052.9446 (4) cm?1 for 0310–0110 and 1057.7860 (5) cm?1 for 0400–0200, and dipole moments, 0.7035 (16) D for 0110 and 0.6810 (24) D for 031P, are obtained. 相似文献
125.
Kanai A Takeda Y Kuramochi K Nakazaki A Kobayashi S 《Chemical & pharmaceutical bulletin》2007,55(3):495-499
The synthesis of the key intermediate (4) in the proposed route to D8646-2-6 is described. The aldol reaction of the carbohydrate-containing pyrone 7 with the aldehyde 6 was accomplished by using LiHMDS and Sc(OTf)3 or Sn(OTf)2. The stepwise dehydration reaction of the aldol adduct 14, followed by Stille coupling with vinyl stannane 5 which contained phosphonate gave the desired 4. 相似文献
126.
Suzuki T Horie Y Koike K Satake M Oshima Y Iwataki M Yoshimatsu S 《Journal of chromatography. A》2007,1142(2):172-177
Several strains of Protoceratium reticulatum, one of the dinoflagellates producing yessotoxins (YTXs), were collected from various shellfish producing areas in Japan. YTXs in the cultured strains were analyzed by liquid chromatography-mass spectrometry (LC-MS). Neutral loss scan monitoring, multiple reaction monitoring (MRM) for more than 20 YTX analogues, and full-scan MS/MS spectra obtained with a hybrid triple quadrupole/linear ion trap mass spectrometer showed that yessotoxin (YTX), 45,46,47-trinoryessotoxin (trinorYTX), 1-homoyessotoxin (homoYTX), and 45,46,47-trinor-1-homoyessotoxin (trinor-1-homoYTX) were the dominant toxins in these strains of P. reticulatum. Enone isomer of 42,43,44,45,46,47,55-heptanor-41-oxoyessotoxin (noroxoYTX enone) was also detected in some strains. Toxin profiles and contents were different among the strains. Some strains produced YTX, trinorYTX, 1-homoYTX, trinor-1-homoYTX, and noroxoYTX enone, whereas other strains produced only YTX or 1-homoYTX. This is the first identification of 1-homoYTX and noroxoYTX enone in P. reticulutum in Japan. Some strains did not produce any detectable YTX analogues. 相似文献
127.
The drug release profile from calcium-induced alginate gel beads coated with an alginate hydrolysate
Murata Y Jinno D Liu D Isobe T Kofuji K Kawashima S 《Molecules (Basel, Switzerland)》2007,12(11):2559-2566
Calcium-induced alginate gel bead (Alg-Ca) coated with an alginate hydrolysate (Alg), e.g. the guluronic acid block (GB) was prepared and the model drug, hydrocortisone release profiles were investigated under simulated gastrointestinal conditions. Their molecular weights were one sixth or one tenth that of Alg and the diffraction patterns of the hydrolysates resembled that of Alg. The drug release rate from Alg-Ca coated with GB apparently lowered than that of Alg-Ca (coating-free) in the gastric juice (pH1.2). And the coating did not resist the disintegration of Alg-Ca in the intestinal juice (pH 6.8) and the gel erosion accelerated the drug release. On the other hand, for the coated Alg-Ca containing chitosan, the drug release showed zero-order kinetics without rapid erosion of Alg-Ca. The drug release rate from Alg-Ca was able to be controlled by the coating and modifying the composition of the gel matrix. 相似文献
128.
Yoshifumi Ando 《Transactions of the American Mathematical Society》2007,359(2):489-515
Let and be smooth manifolds of dimensions and ( ) respectively. Let denote an open subspace of which consists of all Boardman submanifolds of symbols with . An -regular map refers to a smooth map such that . We will prove what is called the homotopy principle for -regular maps on the existence level. Namely, a continuous section of over has an -regular map such that and are homotopic as sections.
129.
Efficient Total Synthesis of Bongkrekic Acid and Apoptosis Inhibitory Activity of Its Analogues
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Dr. Kenji Matsumoto Masaki Suyama Satoshi Fujita Takuya Moriwaki Yukiko Sato Yoshifumi Aso Satoshi Muroshita Hiroshi Matsuo Keishi Monda Dr. Katsuhiro Okuda Dr. Masato Abe Dr. Hiroyuki Fukunaga Prof. Arihiro Kano Prof. Mitsuru Shindo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(32):11590-11602
Bongkrekic acid (BKA), isolated from the bacterium Burkholderia cocovenenans, is an inhibitor of adenine nucleotide translocator, which inhibits apoptosis, and is thus an important tool for the mechanistic investigation of apoptosis. An efficient total synthesis of BKA has been achieved by employing a three‐component convergent strategy based on Kocienski–Julia olefination and Suzuki–Miyaura coupling. It is noteworthy that segment B has been prepared as a new doubly functionalized coupling partner, which contributes to shortening of the number of steps. Torquoselective olefination with an ynolate has also been applied for the efficient construction of an unsaturated ester. Furthermore, it is revealed that 1‐methyl‐2‐azaadamantane N‐oxyl is an excellent reagent for final oxidation to afford BKA in high yield. Based on the total synthesis, several BKA analogues were prepared for structure–activity relationship studies, which indicated that the carboxylic acid moieties were essential for the apoptosis inhibitory activity of BKA. More easily available BKA analogues with potent apoptosis inhibitory activity were also developed. 相似文献
130.
Cover Picture: Ruthenium‐Immobilized Periodic Mesoporous Organosilica: Synthesis,Characterization, and Catalytic Application for Selective Oxidation of Alkanes (Chem. Eur. J. 44/2015)
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