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711.
Yoshimasa Makita Kenta FuruyoshiKeisuke Ikeda Tomoyuki FujitaShin-ichi Fujiwara Masahiro EharaAkiya Ogawa 《Tetrahedron letters》2011,52(32):4129-4131
A cyclotriveratrylene (CTV)-capped azaphosphatrane 4, which contains an endohedral proton within the cavity of the azaphosphatrane, was synthesized in high yield and then characterized. The endohedral proton of 4 was highly sheltered from strongly basic conditions by the CTV-capped structure. 相似文献
712.
Mitsunori Honda Kenta NakaeToshiaki Nishizawa Mitsuhiro SudaKo-Ki Kunimoto Masahito Segi 《Tetrahedron》2011,67(49):9500-9508
The reaction of silylcyclopropyl bromides with dichloromethyl methyl ether in the presence of n-butyllithium is investigated. Under basic reaction conditions, the corresponding cyclopropylidene derivatives are exclusively obtained. The resulting cyclopropylidene compounds are subjected to protonolysis or trapping with electrophiles in a one-pot to give the cyclopropyl silyl ketone derivatives in good yields. Acidic treatment of derived cyclopropyl silyl ketone allows isomerization to give the thermodynamically favorable trans form exclusively. 相似文献
713.
The hippocampal formation is a brain system that is implicated in learning and memory. The major input to the hippocampus arrives from the entorhinal cortex (EC) to the dentate gyrus (DG) through the perforant path. In the present work, we have investigated the functional properties of this connection by concomitantly applying electrophysiological techniques, deep-brain electric microstimulation and functional magnetic resonance imaging in anesthetized rats. We systematically delivered different current intensities at diverse stimulation frequencies to the perforant path while recording electrophysiological and blood-oxygenation-level-dependent (BOLD) signals. We observed a linear relationship between the current intensity used to stimulate the hippocampal formation and the amplitude and extension of the induced BOLD response. In addition, we found a frequency-dependent spatial pattern of activation. With stimulation protocols and train frequencies used for kindling, the activity strongly spreads ipsilaterally through the hippocampus, DG, subiculum and EC. 相似文献
714.
Abe S Ebihara T Enomoto S Furuno K Gando Y Ichimura K Ikeda H Inoue K Kibe Y Kishimoto Y Koga M Kozlov A Minekawa Y Mitsui T Nakajima K Nakajima K Nakamura K Nakamura M Owada K Shimizu I Shimizu Y Shirai J Suekane F Suzuki A Takemoto Y Tamae K Terashima A Watanabe H Yonezawa E Yoshida S Busenitz J Classen T Grant C Keefer G Leonard DS McKee D Piepke A Decowski MP Detwiler JA Freedman SJ Fujikawa BK Gray F Guardincerri E Hsu L Kadel R Lendvai C Luk KB Murayama H O'Donnell T Steiner HM Winslow LA 《Physical review letters》2008,100(22):221803
The KamLAND experiment has determined a precise value for the neutrino oscillation parameter Deltam21(2) and stringent constraints on theta12. The exposure to nuclear reactor antineutrinos is increased almost fourfold over previous results to 2.44 x 10(32) proton yr due to longer livetime and an enlarged fiducial volume. An undistorted reactor nu[over]e energy spectrum is now rejected at >5sigma. Analysis of the reactor spectrum above the inverse beta decay energy threshold, and including geoneutrinos, gives a best fit at Deltam21(2)=7.58(-0.13)(+0.14)(stat) -0.15+0.15(syst) x 10(-5) eV2 and tan2theta12=0.56(-0.07)+0.10(stat) -0.06+0.10(syst). Local Deltachi2 minima at higher and lower Deltam21(2) are disfavored at >4sigma. Combining with solar neutrino data, we obtain Deltam21(2)=7.59(-0.21)+0.21 x 10(-5) eV2 and tan2theta12=0.47(-0.05)+0.06. 相似文献
715.
Yusuke Murayama Felix Bieβmann Frank C. Meinecke Klaus-Robert Müller Mark Augath Axel Oeltermann Nikos K. Logothetis 《Magnetic resonance imaging》2010
Functional magnetic resonance imaging (fMRI) based on the so-called blood oxygen level-dependent (BOLD) contrast is a powerful tool for studying brain function not only locally but also on the large scale. Most studies assume a simple relationship between neural and BOLD activity, in spite of the fact that it is important to elucidate how the “when” and “what” components of neural activity are correlated to the “where” of fMRI data. Here we conducted simultaneous recordings of neural and BOLD signal fluctuations in primary visual (V1) cortex of anesthetized monkeys. We explored the neurovascular relationship during periods of spontaneous activity by using temporal kernel canonical correlation analysis (tkCCA). tkCCA is a multivariate method that can take into account any features in the signals that univariate analysis cannot. The method detects filters in voxel space (for fMRI data) and in frequency–time space (for neural data) that maximize the neurovascular correlation without any assumption of a hemodynamic response function (HRF). Our results showed a positive neurovascular coupling with a lag of 4–5 s and a larger contribution from local field potentials (LFPs) in the γ range than from low-frequency LFPs or spiking activity. The method also detected a higher correlation around the recording site in the concurrent spatial map, even though the pattern covered most of the occipital part of V1. These results are consistent with those of previous studies and represent the first multivariate analysis of intracranial electrophysiology and high-resolution fMRI. 相似文献
716.
Shinji Watanabe Hitoshi Murayama Miki Murata Yuzuru Masuda Masaru Tanabe Yoshio Imai 《Journal of polymer science. Part A, Polymer chemistry》1998,36(13):2229-2235
New polyarylates having benzopinacolone units were synthesized from 2,2-bis(4-hydroxyphenyl)-1,2-diphenylethanone and aromatic dicarboxylic acid chlorides. The polymers having an inherent viscosity of 0.71–0.94 dL/g were obtained by the two-phase method using toluene as an organic solvent. The polymers were easily soluble in various organic solvents and had high glass transition temperatures in the range of 200–240°C. An aromatic polyether having benzopinacolone unit was also prepared. However, its inherent viscosity was low because of the occurrence of a side reaction. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2229–2235, 1998 相似文献
717.
Dr. Hirofumi Ueda Dr. Soichiro Sato Kenta Noda Dr. Hiroyuki Hakamata Dr. Eunsang Kwon Prof. Dr. Nagao Kobayashi Prof. Dr. Hidetoshi Tokuyama 《Angewandte Chemie (International ed. in English)》2023,62(22):e202302404
Biomimetic oxidative dimerization of tryptophan derivatives in aqueous media with oxygen as a bulk oxidant catalyzed by an iron octacarboxy phthalocyanine complex was established. The discovery of the extremely active iron catalyst enables aerobic enzyme-mimetic oxidation to be performed in a flask. This method was applicable to the oxidative dimerization of a wide range of tryptophan derivatives, including various dipeptides and oligopeptides, with remarkable functional-group tolerance without the protection of the amino acid residues. Furthermore, oxidative dimerization of tryptophan derivatives bearing dioxopiperazine units enabled the convergent total synthesis of five natural pyrroloindole compounds and unnatural congeners. The established chemical method provides facile access to a broad range of dimerized peptides with a unique scaffold to link two turn structures, which will serve as a powerful tool to create new small- and medium-sized-molecules as drug candidates. 相似文献
718.
Dr. Daichi Kato Dr. Peng Song Dr. Hiroki Ubukata Haruki Taguro Dr. Cédric Tassel Dr. Kohei Miyazaki Prof. Takeshi Abe Dr. Kousuke Nakano Prof. Kenta Hongo Prof. Ryo Maezono Prof. Hiroshi Kageyama 《Angewandte Chemie (International ed. in English)》2023,62(30):e202301416
Mixed-anion compounds have attracted growing attentions, but their synthesis is challenging, making a rational search desirable. Here, we explored LaF3-LaX3 (X=Cl, Br, I) system using ab initio structure searches based on evolutionary algorithms, and predicted LaF2X and LaFX2 (X=Br, I), which are respectively isostructural with LaHBr2 and YH2I, consisting of layered La-F blocks with single and double ordered honeycomb lattices, separated by van der Waals gaps. We successfully synthesized these compounds: LaF2Br and LaFI2 crystallize in the predicted structure, while LaF2I is similar to the predicted one but with different layer stacking. LaF2I exhibits fluoride ion conductivity comparable to that of non-doped LaF3, and has the potential to show better ionic conductivity upon appropriate doping, given the theoretically lower diffusion energy barrier and the presence of soft iodine anions. This study shows the structure prediction using evolutionary algorithms will accelerate the discovery of mixed-anion compounds in future, in particular those with an ordered anion arrangement. 相似文献
719.
720.
Dr. Haruno Murayama Dr. Qi-An Huang Dr. Eiji Yamamoto Prof. Dr. Makoto Tokunaga Dr. Tamao Ishida Dr. Mitsutaka Okumura Dr. Tetsuo Honma Dr. Tadahiro Fujitani Dr. Atsuko Isogai 《Chemical record (New York, N.Y.)》2023,23(11):e202300148
Heterogeneous noble metal catalysts exhibit various functions. Although their redox functions have been extensively studied, we focused on their soft Lewis acid functions. Supported Au, Pt, and Pd catalysts electrophilically attack the π-electrons of soft bases such as alkynes, alkenes, and aromatic compounds to perform addition and substitution reactions. Hydroamination, intramolecular cyclization of alkynyl carboxylic acids, isomerization of allylic esters, vinyl exchange reactions, Wacker oxidation, and oxidative homocoupling of aromatics are introduced based on a discussion of the active species and reaction mechanisms. Furthermore, the adsorption of sulfur compounds, which are soft bases, onto the supported AuNPs is discussed. The adsorption and removal of 1,3-dimethyltrisulfane (DMTS), which is the compound responsible for the stale odor of “hine-ka” in alcoholic beverages, particularly Japanese sake, is described. 相似文献