• 제목/요약/키워드: Torsion group

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The Crystal Structure of Naproxen Sodium, ($C_{14}H_{13}O_3Na$), A Non-steroidal Antiinflammatory Agent

  • Kim, Yang-Bae;Park, Il-Yeong;Lah, Woon-Ryong
    • Archives of Pharmacal Research
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    • 제13권2호
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    • pp.166-173
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    • 1990
  • The structure of the anti-inflammatory agent, naproxen sodium was determined by single crystal X-ray diffraction analysis. Crystal of the compound, which was recrystallized from methanol solution, is nomoclinic, space group $P2_1$ with a = 21. 177(6), b = 5.785(2), c = 5.443(2) $\AA, \beta$ = 91.41(3)$\{\circ}$ and Z = 2. The calculated density is 1.346; the observed value is nements based on 1093 reflections ($F\geq3\sigma$(F)) gave the final R value of 0.043. There are of one water per one compound molecule in the crystal. The carboxyl group of the molecule is nearly perpendicular to the naphthalene ring. The molecules are arranged along with the screw axis, and stabilized by five 0...Na type interactions. The molecule retains nearly same dimensions and similar conformation compared to its parent compound, naproxen, except for the torsion angles around C(5)-C(11) bond.

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계산화학적 방법을 통한 β-D-glucopyranose 구조 연구 (Computational Studies of the β-D Glucopyranose Structure)

  • 양지현;김진아;이상민;안익성;민병진
    • 대한화학회지
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    • 제57권5호
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    • pp.554-559
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    • 2013
  • 본 연구에서는 ${\beta}$-D-glucopyranose 분자의 hydroxymethyl group의 두 torsion angle의 변화에 따른 포텐셜 에너지의 변화를 진공 상태와 implicit water 상태에서 연구하였으며 이를 통해 Solvation Energy가 구조에 미치는 영향에 대해서 알아보았다. 계산에 사용한 프로그램은 AMBER package였으며, force field는 GLYCAM_06을 사용하였다. Solvation model은 Hawkins, Cramer, Truhlar 등이 제안한 generalized Born model을 사용하였다. 계산 결과, methyl hydroxyl group 내의 hydroxyl group이 고리구조의 hydroxyl group과 강한 수소결합이 가능한 영역에서 많은 변화가 일어났다. 이를 통해 solvation effect로 인해서 수소 결합의 중요성이 감소했다는 결론을 내렸다.

Tertiary Structure of Ganglioside $G_{A1}$ as Determined by NMR Spectroscopy

  • 이경익;이상원;전길자;김양미
    • Bulletin of the Korean Chemical Society
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    • 제19권5호
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    • pp.569-575
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    • 1998
  • Investigation of the structure of the gangliosides has proven to be very important in the understanding of their biological roles. We have determined the tertiary structure of asialoganglioside GM1 $(GA_1)$ using NMR spectroscopy and distance geometry calculations. All of the structures are very similar except the glycosidic torsion angles in the ring IV and ring III linkages. There are two low-energy structures for GA1, G1 and G2. G1 differs from G2 only in the IV-III glycosidic linkages and the orientation of acetamido group in ring III. There is a stable intramolecular hydrogen bond between the third hydroxyl group in ring I and the ring oxygen atom in ring II. Also, there may be a weak hydrogen bond between the second hydroxyl group in ring IV and the acetamido group in ring III. Small coupling constants of $^3J_{IH3,IOH3}\; and\; ^3J_{IVH2,IVOH2}$ support this result. Overall structural features of $(GA_1)$ are very similar to those of $(GM_1)$. It implicates that specificities of the sugar moieties in GM1 are caused not by their tertiary foldings, but mainly by the electrostatic interactions between the polar sialic acid and its receptors. Since it is evident that $(GA_1)$ is more hydrophobic than $(GA_1)$, a receptor with a hydrophobic binding site can recognize the $(GA_1)$ better than $(GA_1)$. Studies on the conformational properties of $(GA_1)$ may lead to a better understanding of the molecular basis of its functions.

카드뮴으로 유발된 산화적 스트레스에 대한 침 자극의 신장 보호 효과 (The Protective Effects of Acupuncture on Oxidative Stress Caused by Cadmium in the Kidney)

  • 신화영;이현종;김재수
    • Journal of Acupuncture Research
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    • 제32권1호
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    • pp.1-11
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    • 2015
  • Objectives : This study was performed to inquire into the protective effects of acupuncture on oxidative stress caused by cadmium accumulation in the kidney. Methods : Sprague-Dawley male($150{\pm}30g$) rats were stabilized for 1 week and divided into 5 groups: normal, control, $LR_3$ acupuncture, $BL_{23}$ acupuncture and sham acupuncture. For three days experimental groups received oral doses of cadmium 2 mg/kg twice a day. Acupuncture was applied bilaterally at each point 10 times for two weeks. The depth of stimulation was 1 mm at right angles and torsion of acupuncture was produced 2 times per second for 1 minute. The kidneys were extracted and weighed after two weeks, and renal function was confirmed through blood urea nitrogen(BUN). We measured reactive oxygen species of the serum and kidney, and compared expression levels of superoxide dismutase(SOD), catalase, glutathione peroxidase(Gpx), nuclear factor erythroid derived 2-related factor 2(Nrf-2), heme oxygenase-1(HO-1), nuclear factor-${\kappa}B$(NF-${\kappa}B)$, cyclooxygenase-2(COX-2), inducible nitric oxide synthase (iNOS), Bax and Cytochrome c. Results : The $LR_3$ acupuncture group and $BL_{23}$ acupuncture group experienced significantly increased kidney weight, and decreased BUN compared to control group. In terms of oxidative stress, the $LR_3$ acupuncture group and $BL_{23}$ acupuncture group experienced significantly reduced reactive oxygen species compared to the control group. Conclusions : The $LR_3$ acupuncture group and $BL_{23}$ acupuncture group experienced showed the effects of antioxidant, anti-inflammatory and apoptosis protection. The $BL_{23}$ acupuncture group was more effective than $LR_3$ acupuncture group.

Application of aerospace structural models to marine engineering

  • Pagani, A.;Carrera, E.;Jamshed, R.
    • Advances in aircraft and spacecraft science
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    • 제4권3호
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    • pp.219-235
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    • 2017
  • The large container ships and fast patrol boats are complex marine structures. Therefore, their global mechanical behaviour has long been modeled mostly by refined beam theories. Important issues of cross section warping and bending-torsion coupling have been addressed by introducing special functions in these theories with inherent assumptions and thus compromising their robustness. The 3D solid Finite Element (FE) models, on the other hand, are accurate enough but pose high computational cost. In this work, different marine vessel structures have been analysed using the well-known Carrera Unified Formulation (CUF). According to CUF, the governing equations (and consequently the finite element arrays) are written in terms of fundamental nuclei that do not depend on the problem characteristics and the approximation order. Thus, refined models can be developed in an automatic manner. In the present work, a particular class of 1D CUF models that was initially devised for the analysis of aircraft structures has been employed for the analysis of marine structures. This class, which was called Component-Wise (CW), allows one to model complex 3D features, such as inclined hull walls, floors and girders in the form of components. Realistic ship geometries were used to demonstrate the efficacy of the CUF approach. With the same level of accuracy achieved, 1D CUF beam elements require far less number of Degrees of Freedom (DoFs) compared to a 3D solid FE solution.

Factors Affecting Tibial Tuberosity-Trochlear Groove Distance in Recurrent Patellar Dislocation

  • Prakash, Jatin;Seon, Jong-Keun;Ahn, Hyeon-Woon;Cho, Kyu-Jin;Im, Chae-Jin;Song, Eun Kyoo
    • Clinics in Orthopedic Surgery
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    • 제10권4호
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    • pp.420-426
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    • 2018
  • Background: The tibial tuberosity-trochlear groove (TT-TG) distance is used to determine the necessity of tibial tubercle osteotomy. We conducted this study to determine the extent to which each of the tibial tuberosity lateralization, trochlear groove medialization, and knee rotation angle affects the TT-TG distance in both normal and patella dislocated patients and thereby scrutinize the rationale for tuberosity transfer based on the TT-TG distance. Methods: Retrospective analysis of rotational profile computed tomography was done for patella dislocated and control group patients. Femoral anteversion, tibial torsion, knee rotation angle, tuberosity lateralization, and trochlear groove medialization were assessed in all patients. Relationship of these parameters with the TT-TG distance was investigated to evaluate their effects on the TT-TG distance. Results: We observed that the patellar dislocation group, compared to the control group, had increased TT-TG distance (mean, 19.05 mm vs. 9.02 mm) and greater tuberosity lateralization (mean, 64.1% vs. 60.7%) and tibial external rotation in relation to the femur (mean, $7.9^{\circ}$ vs. $-0.81^{\circ}$). Conclusions: Tuberosity lateralization and knee rotation were factors affecting patellar dislocation. These factors should be considered in addition to the TT-TG distance to determine the need for tibial tubercle osteotomy in patients with patellar dislocation.

술포닐 우레아 유도체들의 형태분석 (Conformational Analysis of Sulfonylureas)

  • 강기롱;이성희;정우태
    • 약학회지
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    • 제36권6호
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    • pp.518-528
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    • 1992
  • To determine the optimal conformation of sulfonylureas, the correlation between conformation and hypoglycemic activity of the two sulfonylureas of tolbutamide and chlorpropamide as hypoglycemic agent was studied using an empirical potential function (ECEPP/2) and the hydration shell model in the unhydrated and hydrated states. The conformational energy was minimized from several starting conformations with possible torsion angles in each molecule. The conformational entropy change of each conformation was computed using a harmonic approximation. To understand the hydration effect on the conformation of the molecules in aqueous solution, the contribution of water-accessible volume of each group or atom in the lowest-free-energy conformation was calculated and compared each other. From comparison of the computed lowest-free-energy conformations of two sulfonylureas, it could be suggested that the hydration of sulfonylurea moiety is related to increase the hypoglycemic activity. From the calculation results, it was known that the conformational entropy is the major contribution to stabilize the low-free-energy conformations of two sulfonylureas in unhydrated state. Whereas, in hydrated state, the hydration free energy largely contributes to the total free energies of low-free-energy conformations of tolbutamide and conformational entropy contributes to stabilize the low-free-energy conformations of chlorpropamide. The torsion angles from phenyl ring to urea moiety of the low-free-energy conformations of the two sulfonylureas were shown the nearly regular trend. On the basis of these results, the conformation exhibiting the optimal hypoglycemic activity of sulfonylureas and the binding direction to pancreatic receptor site A could be predicted. Also, according to the side chain lengthening of urea moiety, tolbutamide showed various conformational change. Therefore, steric effect may be important factor in the interaction between sulfonylureas and the putative pancreatic receptor.

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Electronic Properties and Conformation Analysis of π-Conjugated Distyryl Benzene Derivaties

  • Kim, Cheol-Ju
    • Bulletin of the Korean Chemical Society
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    • 제23권2호
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    • pp.330-336
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    • 2002
  • A quantum-chemical investigation on the conformations and electronic properties of bis[2-{2-methoxy-4,6-di(t-butyl)phenyl}ethenyl]benzenes (MBPBs) as building block for ${\pi}$-conjugate polymer are performed in order to display the effects of t-butyl and methoxy group substitution and of kink(ortho and meta) linkage. The conjugation length of the polymers can be controlled by substituents and kink linkages of backbone. Structures for the molecules, o-, m-, and p-MBPBs as well as unsubstituted o-, m-, and p-DSBs were fully optimized by using semiempirical AM1, PM3 methods, and ab initio HF method with 3-21G(d) basis set. The potential energy curves with respect to the change of single torsion angle are obtained by using semiempirical methods and ab initio HF/3-21G(d) basis set. The curves are similar shape in the molecules with respect to the position of vinylene groups. It is shown that the conformations of the molecules are compromised between the steric repulsion interaction and the degree of the conjugation. Electronic properties of the molecules were obtained by applying the optimized structures and geometries to the ZINDO/S method. ZINDO/S analysis performed on the geometries obtained by AM1 method and HF/3-21G(d) level is reported. The absorption wavelength on the geometries obtained by AM1 method is much longer than that by HF/3-21G(d) level. The absorption wavelength of MBPBs are red shifted with comparison to that of corresponding DSBs in the same torsion angle because of electron donating substituents. The absorption wavelength of isomers with kink(orth and meta) linkage is shorter than that of para linkage.

ON THE STRUCTURE OF NON-COMMUTATIVE TORI

  • Boo, Deok-Hoon;Park, Won-Gil
    • 충청수학회지
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    • 제13권1호
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    • pp.1-11
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    • 2000
  • The non-commutative torus $A_{\omega}=C^*(\mathbb{Z}^n,{\omega})$ may be realized as the $C^*$-algebra of sections of a locally trivial $C^*$-algebra bundle over $\widehat{S_{\omega}}$ with fibres $C^*(\mathbb{Z}^n/S_{\omega},{\omega}_1)$ for some totally skew multiplier ${\omega}_1$ on $\mathbb{Z}^n/S_{\omega}$. It is shown that $A_{\omega}{\otimes}M_l(\mathbb{C})$ has the trivial bundle structure if and only if $\mathbb{Z}^n/S_{\omega}$ is torsion-free.

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REAL POLYHEDRAL PRODUCTS, MOORE'S CONJECTURE, AND SIMPLICIAL ACTIONS ON REAL TORIC SPACES

  • Kim, Jin Hong
    • 대한수학회보
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    • 제55권4호
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    • pp.1051-1063
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    • 2018
  • The real moment-angle complex (or, more generally, real polyhedral product) and its real toric space have recently attracted much attention in toric topology. The aim of this paper is to give two interesting remarks regarding real polyhedral products and real toric spaces. That is, we first show that Moore's conjecture holds to be true for certain real polyhedral products. In general, real polyhedral products show some drastic difference between the rational and torsion homotopy groups. Our result shows that at least in terms of the homotopy exponent at a prime this is not the case for real polyhedral products associated to a simplicial complex whose minimal missing faces are all k-simplices with $k{\geq}2$. Moreover, we also show a structural theorem for a finite group G acting simplicially on the real toric space. In other words, we show that G always contains an element of order 2, and so the order of G should be even.