排序方式: 共有63条查询结果,搜索用时 31 毫秒
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Chahinez Benbayer Salima Saidi-Besbes Elisabeth Taffin de Givenchy Sonia Amigoni Frédéric Guittard Aicha Derdour 《Colloid and polymer science》2014,292(7):1711-1717
The radical copolymerization of three polymerizable surfactants with styrene was investigated by NMR spectroscopy to assess their compositions. The reactivity ratios of these monomers were calculated according to the methods of Fineman–Ross and Kelen–Tüdos. Consequently, Q and e values were deduced by the Alfrey and Price method. The results indicated the positive effect of the fluorine chain on the reactivity of monomers bearing a long spacer between the ammonium head and the acrylic function. These monomers exhibit high e values which are in favor of an intramolecular conformation of the surfactant where the ester carbonyl function of the polymerizable group interacts with the onium nitrogen atom via a compact six-sided structure. 相似文献
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Sahel Fatma Sebih Fatiha Bellahouel Salima Bengueddach Abdelkader Hamacha Rachida 《Research on Chemical Intermediates》2020,46(1):133-148
Research on Chemical Intermediates - Low-cost Al-MCM-41 and Al-SBA-15 mesoporous materials are successfully synthesized from bentonite as silicon and aluminum sources instead of laboratory reagents... 相似文献
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The third instar larva of Sarcophaga hirticrus Pandellé, 1896 and Sarcophaga javita (Peris, González-Mora and Mingo, 1998) are described and figured for the first. The use of scanning electron microscopy (SEM) has been demonstrated as an effective tool for determining differences at the specific level, and is here applied. The two species are distinguished from other Sarcophaga spp. and the principal diagnostic character states are illustrated and discussed. Comparative information on immature stages morphology of the described Palaearctic Sarcophaga species and its feeding habits are compiled and provided in a tabulated form. 相似文献
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Nargis Jamila Khaw Kooi Yeong Vikneswaran Murugaiyah Amir Atlas Imran Khan Naeem Khan 《Natural product research》2015,29(1):86-90
Garcinia species are reported to possess antimicrobial, anti-inflammatory, anticancer, anti-HIV and anti-Alzheimer's activities. This study aimed to investigate the in vitro cholinesterase enzyme inhibitory activities of garcihombronane C (1), garcihombronane F (2), garcihombronane I (3), garcihombronane N (4), friedelin (5), clerosterol (6), spinasterol glucoside (7) and 3β-hydroxy lup-12,20(29)-diene (8) isolated from Garcinia hombroniana, and to perform molecular docking simulation to get insight into the binding interactions of the ligands and enzymes. The cholinesterase inhibitory activities were evaluated using acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. In this study, compound 4 displayed the highest concentration-dependent inhibition of both AChE and BChE. Docking studies exhibited that compound 4 binds through hydrogen bonds to amino acid residues of AChE and BChE. The calculated docking and binding energies also supported the in vitro inhibitory profiles of IC50. In conclusion, garcihombronanes C, F, I and N (1–4) exhibited dual and moderate inhibitory activities against AChE and BChE. 相似文献
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Lee KS Kim SR Park HS Park SJ Min KH Lee KY Choe YH Hong SH Han HJ Lee YR Kim JS Atlas D Lee YC 《Experimental & molecular medicine》2007,39(6):756-768
Reactive oxygen species (ROS) play an important role in the pathogenesis of airway inflammation and hyperresponsiveness. Recent studies have demonstrated that antioxidants are able to reduce airway inflammation and hyperreactivity in animal models of allergic airway disease. A newly developed antioxidant, small molecular weight thiol compound, N-acetylcysteine amide (AD4) has been shown to increase cellular levels of glutathione and to attenuate oxidative stress related disorders such as Alzheimer's disease, Parkinson's disease, and multiple sclerosis. However, the effects of AD4 on allergic airway disease such as asthma are unknown. We used ovalbumin (OVA)-inhaled mice to evaluate the role of AD4 in allergic airway disease. In this study with OVA-inhaled mice, the increased ROS generation, the increased levels of Th2 cytokines and VEGF, the increased vascular permeability, the increased mucus production, and the increased airway resistance in the lungs were significantly reduced by the administration of AD4. We also found that the administration of AD4 decreased the increases of the NF-kappaB and hypoxia-inducible factor-1alpha (HIF-1alpha) levels in nuclear protein extracts of lung tissues after OVA inhalation. These results suggest that AD4 attenuates airway inflammation and hyperresponsiveness by regulating activation of NF-kappaB and HIF-1alpha as well as reducing ROS generation in allergic airway disease. 相似文献
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The central focus of this paper is upon the alleviation of the boundary problem when the probability density function has a bounded support. Mixtures of beta densities have led to different methods of density estimation for data assumed to have compact support. Among these methods, we mention Bernstein polynomials which leads to an improvement of edge properties for the density function estimator. In this paper, we set forward a shrinkage method using the Bernstein polynomial and a finite Gaussian mixture model to construct a semi-parametric density estimator, which improves the approximation at the edges. Some asymptotic properties of the proposed approach are investigated, such as its probability convergence and its asymptotic normality. In order to evaluate the performance of the proposed estimator, a simulation study and some real data sets were carried out. 相似文献
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Salima Lakehal Nadia Ouddai Douniazed Hannachi Mohmed Bououdina 《International journal of quantum chemistry》2013,113(10):1447-1452
Theoretical studies on ytterbium trichelates, Yb(L)3(L = trifluoromethanesulfonate (OTF), perchlorate (ClO4), p‐toluenesulfonic (TOS), nitrobenzenesulfonic (NBSA), and dodecylsulfate (DOS), are carried out using density functional theory method at the PW91/TZP level, for the first time. All ligands are bidentate and the compounds exhibit a distorted trigonal prismatic structure, with a maximum twist angle obtained for ytterbium p‐toluenesulfonic compound Yb(TOS)3. The quantum theory of atoms in molecules (AIM) and energy decomposition analysis reveal the dominant ionic character in ytterbium–oxygen bonding with a little covalent character. According to the Pearson terminology, the Yb(NBSA)3complex reveals the higher acidity. © 2012 Wiley Periodicals, Inc. 相似文献