• Title/Summary/Keyword: Conformation

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The Crystal Structure of Fluoxymesterone, $C_{20}H_{29}FO_3$ (Fluoxymesterone, $C_{20}H_{29}FO_3$의 결정구조)

  • Kim, Ui-Seong;Park, Gwon-Il;Jo, Seong-Il
    • Korean Journal of Crystallography
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    • v.4 no.1
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    • pp.6-10
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    • 1993

  • 11 β ,17 β -dihydroxy-9a-fluoro-l7a-methyl androst-4-en-3-one (Fluoxymesterone), CgoH29 FO,, orthorhombic, P2,2,2,, a=13.468(5) A, b= 19.554 (2)A, c=6.578(9)A, a=b=r=90˚, A (CuKa)=1.5406 A , Dm=1.289cm-3, Dc=1.299cm-3 and Z=4 at T=298k. The structure was solved by direct method using seminvariants of ggg Parity group and refined by the full-matrix least-square method, resulting model with reliability factor R=0.069 for 1098 unique reflection over 3σ . Ring A is an 1β-2a-half chair, 5 ring has a highly symmetrical chair conformation, C ring is in a distorted chair conformation and D ring is a 13aenveLope conformation. In the crystal structure, the molecules are packed with a hydrogen bond of 011-H23‥‥03(0.5+x, 1.5-y, 1.0-z) [1.94(9) A of H‥‥0.2.786(9)A of 0‥‥0 and 165(8) ˚ of

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Correlation among Conformation Parameters in 'Fuji' Apple Fruit ('후지' 사과 과실의 형태 결정 요인 간 상관)

  • Yoon, Tae-Myung;Han, Su-Gon;Park, Youn-Moon
    • Horticultural Science & Technology
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    • v.19 no.3
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    • pp.358-361
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    • 2001

  • Factors affecting fruit conformation of 'Fuji' apples (Malus domestica Borkh.) were investigated through correlation study of fruit weight, seed numbers, and seed weight in relation to fruit conformation indices. Apples were harvested from two orchards in 'Andong' and 'Youngyang' areas at commercial maturity and grouped by fruit weight. Average number of seeds and seed weight were 8.9 and 0.64 g in 'Andong' orchard, while 6.3 and 0.47 g in 'Youngyang' orchard, respectively. When pooled data from the both orchards were analyzed, correlation of fruit weight with seed weight was significantly positive, whereas that with seed number was not significant. Fruit shape index determined by length/diameter ratio was positively correlated with fruit weight, while relationship of the shape index with seed number or with seed weight was not significant. Asymmetry index tended to be low in apples from the 'Andong' orchard in which higher seed numbers and seed weight were observed. The asymmetry index showed highly negative correlations with seed numbers and with seed weight.

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Crystal Structure of cis-(Malonato)[(4R,5R)-4,5-bis(Aminomethyl)-2-Isopropyl-1,3-Dioxolane]Platinum(II), A Potent Anticancer Agent

  • Cho, Sang-Woo;Yongkee Cho;Kim, Dai-Kee;Wanchul Shin
    • Korean Journal of Crystallography
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    • v.11 no.1
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    • pp.22-27
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    • 2000

  • The structure of cis-(malonato)[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolane]platinum(II) with a potent anticancer activity has been determined by the X-ray crystallographic method. Crystal data are as follows: Pt(C/sub 11/H/sub 20/N₂O/sub 6/), M/sub 4/=471.38, monoclinic, P2₁, a=7.112(1), b=33.615(3), c=7.135(1)Å, β=116.80(1)°, V=1522.6(3)Å, and Z=4. The two independent molecules with very similar structures are approximately related by pseudo two-fold screw axis symmetry, which makes the monolinic cell look like the orthorhombic cell with one molecule in the asymmetric unit and space group C222₁. The crystal packing mode is similar to that of the analogue with the dimethyl substituents instead of the isopropyl group. The Pt atom is coordinate to two O and two N atoms in a square planar structure. The six-membered chelate ring in the leaving ligand assumes a conformation intermediate between the half chair and the boat forms. The seven-membered ring in the carrier ligand assumes a twist-chair conformation and the oxolane ring assumes an envelope conformation. Crystal packing consists of the extensive hydrogen-bonding network in the two-dimensional molecular layers and weak van der Waals interactions between these layers.

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Conformational changes of short, discrete Rouse chain during creep and recovery processes

  • Watanabe, Hiroshi;Inoue, Tadashi
    • Korea-Australia Rheology Journal
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    • v.16 no.2
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    • pp.91-99
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    • 2004

  • For the Rouse chain composed of infinite number of beads (continuous limit), conformational changes during the creep and creep recovery processes was recently analyzed to reveal the interplay among all Rouse eigenmodes under the constant stress condition (Watanabe and Inoue, Rheol. Acta, 2004). For completeness of the analysis of the Rouse model, this paper analyzes the conformational changes of the discrete Rouse chain having a finite number of beads (N = 3 and 4). The analysis demonstrates that the chain of finite N exhibits the affine deformation on imposition/removal of the stress and this deformation gives the instantaneous component of the recoverable compliance, $J_{R}$(0) = 1/(N-l)v $k_{B}$T with v and $k_{B}$ being the chain number density and Boltzmann constant, respectively. (This component vanishes for N\longrightarrow$\infty$.) For N = 2, it is known that the chain has only one internal eigenmode so that the affinely deformed conformation at the onset of the creep process does not change with time t and $J_{R}$(t) coincides with $J_{R}$(0) at any t (no transient increase of $J_{R}$(t)). However, for N$\geq$3, the chain has N-l eigenmodes (N-l$\geq$2), and this coincidence vanishes. For this case, the chain conformation changes with t to the non-affine conformation under steady flow, and this change is governed by the interplay of the Rouse eigenmodes (under the constant stress condition). This conformational change gives the non-instantaneous increase of $J_{R}$(t) with t, as also noted in the continuous limit (N\longrightarrow$\infty$).X>).TEX>).X>).

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