WordNet

a round arch whose inner curve is drawn with circles having three centers (同)basket-handle arch
of or belonging to neither the right nor the left politically or intellectually
a building dedicated to a particular activity; "they were raising money to build a new center for research" (同)centre
(American football) the position of the player on the line of scrimmage who puts the ball in play; "it is a centers responsibility to get the football to the quarterback"
a position on a basketball team of the player who participates in the jump that starts the game
the position on a hockey team of the player who participates in the face off at the beginning of the game
a place where some particular activity is concentrated; "they received messages from several centers" (同)centre
the sweet central portion of a piece of candy that is enclosed in chocolate or some other covering (同)centre
the object upon which interest and attention focuses; "his stories made him the center of the party" (同)centre, center of attention, centre of attention
an area that is approximately central within some larger region; "it is in the center of town"; "they ran forward into the heart of the struggle"; "they were in the eye of the storm" (同)centre, middle, heart, eye
a point equidistant from the ends of a line or the extremities of a figure (同)centre, midpoint
a cluster of nerve cells governing a specific bodily process; "in most people the speech center is in the left hemisphere" (同)centre, nerve_center, nerve centre
(football) the person who plays center on the line of scrimmage and snaps the ball to the quarterback; "the center fumbled the handoff" (同)snapper
(basketball) the person who plays center on a basketball team
(ice hockey) the person who plays center on a hockey team
politically moderate persons; centrists
the middle of a military or naval formation; "they had to reinforce the center"
move into the center; "That vase in the picture is not centered" (同)centre
equally distant from the extremes (同)halfway, middle, midway
being one more than two (同)3, iii
the cardinal number that is the sum of one and one and one (同)3, III, trio, threesome, tierce, leash, troika, triad, trine, trinity, ternary, ternion, triplet, tercet, terzetto, trey, deuce-ace
being or placed in the center

PrepTutorEJDIC

『3』;3の記号(3,?など) / 〈U〉3時,3分;3歳 / 《複数扱い》3人;3個 / 〈C〉三つ(3人,3個)一組のもの / (カードゲーム・さいころなどの)3の札,3の目 / 『3の』,3人の,3個の / 《補語にのみ用いて》3歳の(で)
中軸(中心)を持つ

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1. 三次元心エコー検査 three dimensional echocardiography
2. 医師と患者の関係における患者中心の考え方 a patient centered view of the clinician patient relationship
3. Informed procedural consent
4. ダーモスコピーによる皮膚癌の治療優先順位決定のアルゴリズム dermoscopic algorithms for skin cancer triage
5. 過敏性肺臓炎（外因性アレルギー性肺胞炎）の診断 diagnosis of hypersensitivity pneumonitis extrinsic allergic alveolitis

English Journal

Mechanisms and Origins of Switchable Chemoselectivity of Ni-Catalyzed C(aryl)-O and C(acyl)-O Activation of Aryl Esters with Phosphine Ligands.

Hong X, Liang Y, Houk KN.Author information Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States.AbstractMany experiments have shown that nickel with monodentate phosphine ligands favors the C(aryl)-O activation over the C(acyl)-O activation for aryl esters. However, Itami and co-workers recently discovered that nickel with bidentate phosphine ligands can selectively activate the C(acyl)-O bond of aryl esters of aromatic carboxylic acids. The chemoselectivity with bidentate phosphine ligands can be switched back to C(aryl)-O activation when aryl pivalates are employed. To understand the mechanisms and origins of this switchable chemoselectivity, density functional theory (DFT) calculations have been conducted. For aryl esters, nickel with bidentate phosphine ligands cleaves C(acyl)-O and C(aryl)-O bonds via three-centered transition states. The C(acyl)-O activation is more favorable due to the lower bond dissociation energy (BDE) of C(acyl)-O bond, which translates into a lower transition-state distortion energy. However, when monodentate phosphine ligands are used, a vacant coordination site on nickel creates an extra Ni-O bond in the five-centered C(aryl)-O cleavage transition state. The additional interaction energy between the catalyst and substrate makes C(aryl)-O activation favorable. In the case of aryl pivalates, nickel with bidentate phosphine ligands still favors the C(acyl)-O activation over the C(aryl)-O activation at the cleavage step. However, the subsequent decarbonylation generates a very unstable tBu-Ni(II) intermediate, and this unfavorable step greatly increases the overall barrier for generating the C(acyl)-O activation products. Instead, the subsequent C-H activation of azoles and C-C coupling in the C(aryl)-O activation pathway are much easier, leading to the observed C(aryl)-O activation products.
Journal of the American Chemical Society.J Am Chem Soc.2014 Feb 5;136(5):2017-25. doi: 10.1021/ja4118413. Epub 2014 Jan 23.
Many experiments have shown that nickel with monodentate phosphine ligands favors the C(aryl)-O activation over the C(acyl)-O activation for aryl esters. However, Itami and co-workers recently discovered that nickel with bidentate phosphine ligands can selectively activate the C(acyl)-O bond of aryl
PMID 24428154

Bonding and reactivity of a μ-hydrido dicopper cation.

Wyss CM, Tate BK, Bacsa J, Gray TG, Sadighi JP.Author information School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332 (USA).AbstractA bent dicopper-hydride cation that has an N-heterocyclic carbene supporting ligand has a Cu-H-Cu angle of 122° in the solid state. Density functional theory suggests an open three-centered metal-hydrogen interaction. The hydride reacts readily with methanol and with carbon dioxide; insertion of phenylacetylene affords a gem-dicopper vinyl complex.
Angewandte Chemie (International ed. in English).Angew Chem Int Ed Engl.2013 Dec 2;52(49):12920-3. doi: 10.1002/anie.201306736. Epub 2013 Oct 16.
A bent dicopper-hydride cation that has an N-heterocyclic carbene supporting ligand has a Cu-H-Cu angle of 122° in the solid state. Density functional theory suggests an open three-centered metal-hydrogen interaction. The hydride reacts readily with methanol and with carbon dioxide; insertion of ph
PMID 24132865

Insight into the packing pattern of β2 fibrils: a model study of glutamic acid rich oligomers with 13C isotopic edited vibrational spectroscopy.

Chi H, Welch WR, Kubelka J, Keiderling TA.Author information Department of Chemistry, University of Illinois at Chicago , 845 West Taylor Street (m/c111), Chicago, Illinois 60607-7061, United States.AbstractPolyglutamic acid at low pH forms aggregates and self-assembles into a spiral, fibril-like superstructure formed as a β2-type sheet conformation that has a more compact intersheet packing than commonly found. This is stabilized by three-centered bifurcated hydrogen bonding of the amide carbonyl involving the protonated glutamic acid side chain. We report vibrational spectroscopic results and analyses for oligopeptides rich in glutamic acid enhanced with (13)C isotope labeling in a study modeling low pH poly-Glu self-assembly. Our results indicate bifurcated H-bonding and β2 aggregation can be attained in these model decamers, confirming they have the same conformations as poly-Glu. We also prepared conventional β1-sheet aggregates by rapid precipitation from the residual peptides in the higher pH supernatant. By comparing the isotope-enhanced IR and VCD spectra with theoretical predictions, we deduced that the oligo-Glu β2 structure is based on stacked, twisted, antiparallel β-sheets. The best fit to theoretical predictions was obtained for the strands being out of register, sequentially stepped by one residue, in a ladder-like fashion. The alternate β1 conformer for this oligopeptide was similarly shown to be antiparallel but was less ordered and apparently had a different registry in its aggregate structure.
Biomacromolecules.Biomacromolecules.2013 Nov 11;14(11):3880-91. doi: 10.1021/bm401015f. Epub 2013 Oct 9.
Polyglutamic acid at low pH forms aggregates and self-assembles into a spiral, fibril-like superstructure formed as a β2-type sheet conformation that has a more compact intersheet packing than commonly found. This is stabilized by three-centered bifurcated hydrogen bonding of the amide carbonyl inv
PMID 24053614

Japanese Journal

三円形泥水式シールドの掘削土砂回収に関する実験的研究

猪瀬二郎,西林聖武,藤木育雄 [他],橋本美武
土木学会論文集 = Proceedings of JSCE 540, 59-68, 1996-06-15
NAID 10001792233

Prediction of Intrinsic Defects in Hydrogenated Amorphous Silicon by ab initio Molecular Dynamics

ORITA Nozomi,KATAYAMA-YOSHIDA Hiroshi
Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy 39(1), 33-36, 1994-03-25
… It is predicted that the hydrogen-passivated dangling bond (Si-H), the positively-ionized Si-H-Si three-centered bond (Si-H^+-Si), the negatively-ionized three-fold-coordinated dangling-bond (D^-), and the five-fold-coordinated floating-bond (F_5) are the intrinsic defects in a-Si : H. …
NAID 110004640464

NMRテクニックの有機金属化合物への応用 (構造解析法の進歩<特集>)

小笠原正道,小池誠,佐分利正彦
有機合成化学協会誌 51(6), 484-490, 1993
Application of NMR techniques, especially a spin saturation transfer technique, to several organometallic compounds are reported with emphasis on compounds undergoing fluxional behavior with two-elect …
NAID 130000923826