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211.
4-(1-芳基-3-烃基-3-氧代丙胺基)-N-(5-甲基-3-异噁唑基)苯磺酰胺的 合成与抗糖尿病活性的初步研究 总被引:1,自引:0,他引:1
为寻找新型高效低毒的过氧化物酶体增殖物激活受体(PPAR)激动剂, 通过Mannich反应一步合成了13个含有磺胺甲噁唑结构单元的未见报道的β-氨基酮衍生物, 收率为39.8%~92.5%. 化合物的结构通过IR, 1H NMR, 13C NMR, ESI MS和HRMS表征. 生物活性测试结果表明, 化合物1a能够显著激活PPAR反应元件. 文中还对合成反应条件及化合物结构-活性关系进行了初步讨论. 相似文献
212.
Synthesis and characterization of mixing soft-segmented waterborne polyurethane polymer electrolyte with room temperature ionic liquid 总被引:1,自引:0,他引:1
Composite polymer electrolytes based on mixing soft-segment waterborne polyurethane(WPU)and 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide(BMImTFSI)have been prepared and characterized.The addition of BMImTFSI results in an increase of the ionic conductivity.At high BMImTFSI concentration(BMImTFSI/WPU=3 in weight ratio),the ionic conductivity reaches 4.27×10~(-3)S/cm at 30℃.These composite polymer electrolytes exhibit good thermal and electrochemical stability,which are high enough to be... 相似文献
213.
Mollusk shell formation: a source of new concepts for understanding biomineralization processes 总被引:9,自引:0,他引:9
Addadi L Joester D Nudelman F Weiner S 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(4):980-987
The biological approach to forming crystals is proving to be most surprising. Mollusks build their shells by using a hydrophobic silk gel, very acidic aspartic acid rich proteins, and apparently also an amorphous precursor phase from which the crystals form. All this takes place in a highly structured chitinous framework. Here we present ideas on how these disparate components work together to produce the highly structured pearly nacreous layer of the mollusk shell. 相似文献
214.
Allemand JF Cocco S Douarche N Lia G 《The European physical journal. E, Soft matter》2006,19(3):293-302
DNA loop formation plays a central role in many cellular processes. The aim of this paper is to present the state of the art
and open problems regarding the experimental and theoretical approaches to DNA looping. A particular attention is devoted
to the effects of the protein bridge size and of protein induced sharp DNA bending on DNA loop formation enhancement. 相似文献
215.
216.
We characterize Leavitt path algebras which are Rickart, Baer, and Baer ?-rings in terms of the properties of the underlying graph. In order to treat non-unital Leavitt path algebras as well, we generalize these annihilator-related properties to locally unital rings and provide a more general characterizations of Leavitt path algebras which are locally Rickart, locally Baer, and locally Baer ?-rings. Leavitt path algebras are also graded rings and we formulate the graded versions of these annihilator-related properties and characterize Leavitt path algebras having those properties as well.Our characterizations provide a quick way to generate a wide variety of examples of rings. For example, creating a Baer and not a Baer ?-ring, a Rickart ?-ring which is not Baer, or a Baer and not a Rickart ?-ring, is straightforward using the graph-theoretic properties from our results. In addition, our characterizations showcase more properties which distinguish behavior of Leavitt path algebras from their -algebra counterparts. For example, while a graph -algebra is Baer (and a Baer ?-ring) if and only if the underlying graph is finite and acyclic, a Leavitt path algebra is Baer if and only if the graph is finite and no cycle has an exit, and it is a Baer ?-ring if and only if the graph is a finite disjoint union of graphs which are finite and acyclic or loops. 相似文献
217.
Stan?AlamaEmail authorView authors OrcID profile Lia?Bronsard Xavier?Lamy 《Journal of Nonlinear Science》2018,28(4):1443-1465
We consider a nematic liquid crystal occupying the exterior region in \({\mathbb {R}}^3\) outside of a spherical particle, with radial strong anchoring. Within the context of the Landau-de Gennes theory, we study minimizers subject to an external field, modeled by an additional term which favors nematic alignment parallel to the field. When the external field is high enough, we obtain a scaling law for the energy. The energy scale corresponds to minimizers concentrating their energy in a boundary layer around the particle, with quadrupolar symmetry. This suggests the presence of a Saturn ring defect around the particle, rather than a dipolar director field typical of a point defect. 相似文献
218.
219.
Claudia Da C. Madruga EdÍLia Clerici A. P. Marcos 《Journal of heterocyclic chemistry》1995,32(3):735-738
The synthesis of a series of 5- and 6-substituted 4-trihalomethyl-2-methylthiopyrimidines, prepared from the cyclocondensation reaction of β-alkoxyvinyl tri[fluoro]chloromethyl ketones with 2-methyl-2-thiopseudourea sulfate, are reported. A systematic study to find the best reaction conditions were carried out. 相似文献
220.
Ana Lucia Ramalho Mercê Lia Sayuri Yano Mustayeen Ahmed Khan Xuan Do Thanh Gilles Bouet 《Journal of solution chemistry》2003,32(12):1075-1085
This study reports the stability constants of complexes with vitamin D3 and Al3+, Cd2+, Gd3+ and Pb2+ ions in a water–ethanol medium (30/70% v/v at 25.0°C). The logarithms of the overall stability constants are: 1 = 12.4 ± 0.5, 7.6 ± 0.3, 9.33 ± 0.07, and 9.1 ± 0.5, respectively, whereas the logarithms of 2 are 24.4 ± 0.5 (Al3+), 14.3 ± 0.3 (Cd2+), and 15.4 ± 0.5 (Pb2+). Gd3+ forms only the 1:1 complex. These values are compared to those reported previously and correlations are established between the stability constants and physical properties, such as the ionization energy. 相似文献