976 resultados para REVERSING Z-PLASTY


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The properties of the Z = 117 isotopic chain are studied within the framework of the axially deformed relativistic mean field theory (RMFT) in the blocked BCS approximation. The ground-state properties, such as binging energies, deformations as well as the possible.. decay energies and lifetimes are calculated with the parameter set of NL-Z2 and compared with results from the finite range droplet model. The analysis by RMFT shows that the isotopes in the range of mass number A = 291 similar to 300 exhibit higher stability, which suggests that they may be promising nuclei to be hopefully synthesized in the lab among the nuclei Z = 117.

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The crystal structure of the title compound, C12H10ClF3O3, was determined in order to establish the configuration of the C double bond. The compound was found to be the Z isomer. The crystal structure is dominated by Cl center dot center dot center dot O halogen bonds [Cl center dot center dot center dot O = 3.111 (3) angstrom], as well as C-H center dot center dot center dot O and C-H center dot center dot center dot F hydrogen-bonding interactions, that connect neighboring molecules into a three-dimensional supramolecular network.

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The title compound, C13H11ClF3NO2, adopts a Z conformation. Halogen center dot center dot center dot oxygen interactions [Cl center dot center dot center dot O = 2.967 (3) angstrom] in the crystal packing lead to the formation of a dimer joined by two Cl center dot center dot center dot O bonds.

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Self-assembling of synthesized novel biodegradable hyperbranched amphiphilic poly(ethylene glycol)-polyethylenimine-poly(epsilon-benzyloxycarbonyl-L-lysine) (PEG-PEI-PLys(Z)) in aqueous media is studied. In aqueous media. PLys(Z) is the hydrophobic segment, with PEG and PEI as the hydrophilic segments. It will self-assemble into spherical shape when the selected solvent water is dropped into the common solvent tetrahydrofuran (THF). And when PEG-PEI-PLYS in common solvent is dropped into mixed solvent water and THF, rings will come into King. The spherical and rings are observed by environmental scanning electron microscopy (ESEM) and transmission electron microscopy ITEM). It shows that the size of the sphere is about 100 nm, and the diameter of ring distributes from 400 nm to 10 mu m and bigger with the time roll around.

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We report here that a cubane-like europium-L-aspartic acid complex at physiological pH can discriminate between DNA structures as judged by the comparison of thermal denaturation, binding stoichiometry, temperature-dependent fluorescence enhancement, and circular dichroism and gel electrophoresis studies. This complex can selectively stabilize non-B-form DNA polydApolydT but destabilize polydGdCpolydGdC and polydAdTpolydAdT. Further studies show that this complex can convert B-form polydGdCpolydGdC to Z-form under the low salt condition at physiological temperature 37 degrees C, and the transition is reversible, similar to RNA polymerase, which turns unwound DNA into Z-DNA and converts it back to B-DNA after transcription. The potential uses of a left-handed helix-selective probe in biology are obvious. Z-DNA is a transient structure and does not exist as a stable feature of the double helix. Therefore, probing this transient structure with a metal-amino acid complex under the low salt condition at physiological temperature would provide insights into their transitions in vivo and are of great interest.

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用Z 扫描技术研究了各向同性手性介质 (聚酯酰亚胺吡啶溶液 )对于左、右圆偏振光的非线性圆双折射 ,得到在低光强下非线性旋光角的变化规律 ,验证了非线性圆双折射与非线性旋光的关系。

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比较稀土催聚1,4—聚丁二烯橡胶和几种不同温度下聚合的镍催聚1,4—聚丁二烯橡胶的σy 和[η],从中得知链缠结的变化是影响σy 和[η]以及 τ的主要原因,而微观结构的变化可能是影响链缠结的因素之一,1,4—聚丁二烯橡胶的加工性能与链缠结有关。

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Five new organotin compounds were synthesized and characterized, X-ray crystal structure analysis of (Z)-3-triphenylstannyl-1,1-diphenyl propenol was performed, The crystal belongs to space group P2(1)/n. The cell parameters are: a = 1.235 7(2) nm, b = 0.987 4(2) nm, c = 2.208 1(4) nm, beta = 95.23(3)degrees, V = 2.683 0(9) nm(3), Z = 4, R = 0.027 9, R-w = 0.064 5. The tin atom of the molecule exists in a distorted tetrahedron, Z isomer of double bond is obtained.

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合成并表征了5种新的有机锡化合物.测定了(Z)-3-三苯基锡基-1,1-二苯基烯丙醇的晶体结构.晶体属于P21/n空间群,晶胞参数a=1.2357(3)nm,b=0.9874(2)nm,c=2.2081(2)nm,β=95.23(3)°,Z=4.分子结构是以锡为中心的畸变四面体构型,双键为顺式构型.并对其性质进行了研究.

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报道了标题化合物〔C14H18Br2OSn〕的合成及晶体结构。该晶体属于单斜晶系,空间点群为P21/c,晶胞参数a=11.711(2),b=9.114(2),c=16.864(3)A,β=102.94(1)°,V=1604.55(0)A3,Mr=480.78,Z=4,Dc=1.99g/cm3,u=65.20cm-1,F(000)=919,R=0.050,Rw=0.050.晶体结构由直接法解出。标题化合物分子中的锡原子被配体的2个碳、2个溴和1个氧原子配位,配位原子呈畸变的三角双锥构型,环已基为椅式构象,五员杂环为信封构象。

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The crystal structure and mechanism of the title molecule are described. This crystal is orthorhombic, belonging to space group PC21/B with a=1,002 1(2) nm, b=1.483 0(3) nm, c=2.173 6(4) nm, V=3.230 39(2) nm(3), Z=2, D-c=1.80 g/cm(3), R=0.069 3. The structure was solved by direct method. The tin atom of the title compound exists in two distorted-trigonal-bipyramidal geometry, defined by two carbon, one bromide, one chloride and one oxygen atoms leading to a five-membered chelate ring. In the structure, the five-membered ring containing the intermolecular O-->Sn has a half chair conformation.

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The compounds of [Z]-1-[2-(triphenyl stannyl) vinyl] cyclooctanol (1) and [Z]-1-[2-(tri-p-tolyl stannyl) vinyl] cyclooctanol (2) were synthesized by the reactions of triphenyltin hydride and tri-p-tolyltin hydride with 1-ethynyl cyclooctanol. The crystal structure of compound 1 was determined. The reactions of compound 1 and 2 with IC1, Br-2, I-2 formed nine organotin halides. The organotin oxide or hydroxide were prepared by the reactions of [Z]-1-[2-(phenyl dibromo stannyl) vinyl] cyclooctanol (6) and [Z]-1-[2-(diphenyl monobromo stannyl) vinyl] cyclooctanol (5) with KOH. Three complexes were obtained by the reactions of [Z]-1-[2-(phenyl diiodide stannyl) vinyl] cyclooctanol (8) with three ligands (2,2'-bipyridyl,5-nitro-1,10-phenanthroline,8-Hydroxyquinoline). The sixteen new compounds synthesized in this paper were characterized by means of elemental analysis, IR, H-1 NMR. The reaction mechanism of triphenyltin hydride and tri-p-tolyltin hydride with 1-ethynyl cyclooctanol were also proposed.