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排序方式: 共有138条查询结果,搜索用时 31 毫秒
1.
Loganin ( 1 ), loganic acid ( 2 ), and periclymenoside ( 3 ) have been isolated from Lonicera periclymenum L . The structure of the new compound 3 and the identity of the others have been determined by chemical transformations and interpretation of the spectral data. 相似文献
2.
Talal A. K. Al-Allaf Ihsan A. Mustafa Sa'ad E. Al-Mukhtar 《Transition Metal Chemistry》1993,18(1):1-5
Summary A series of new PtII and PdII complexes of N,N-disubstituted thiourea derivatives of general formulae [MLCl2]2, [ML2Cl2] and [ML4]Cl2 have been prepared and characterised by physicochemical and spectroscopic methods. The reaction of these ligands with [M(DMSO)2Cl2], M = Pt, cis- or Pd, trans-, in CHCl3 and EtOH at ambient temperature or under reflux, is described. 相似文献
3.
In this paper, we present the concept of the logical entropy of order m, logical mutual information, and the logical entropy for information sources. We found upper and lower bounds for the logical entropy of a random variable by using convex functions. We show that the logical entropy of the joint distributions and is always less than the sum of the logical entropy of the variables and . We define the logical Shannon entropy and logical metric permutation entropy to an information system and examine the properties of this kind of entropy. Finally, we examine the amount of the logical metric entropy and permutation logical entropy for maps. 相似文献
4.
Sarosh Iqbal Nimra Naveed Shaikh Khalid Mohammed Khan Shumaila Kiran Sehrish Naz Zaheer Ul-Haq Shahnaz Perveen M. Iqbal Choudhary 《Molecules (Basel, Switzerland)》2022,27(22)
Currently the discovery and development of potent β-glucuronidase inhibitors is an active area of research due to the observation that increased activity of this enzyme is associated with many pathological conditions, such as colon cancer, renal diseases, and infections of the urinary tract. In this study, twenty-seven 2-aminopyrimidine derivatives 1–27 were synthesized by fusion of 2-amino-4,6-dichloropyrimidine with a variety of amines in the presence of triethylamine without using any solvent and catalyst, in good to excellent yields. All synthesized compounds were characterized by EI-MS, HREI-MS and NMR spectroscopy. Compounds 1–27 were then evaluated for their β-glucuronidase inhibitory activity, and among them, compound 24 (IC50 = 2.8 ± 0.10 µM) showed an activity much superior to standard D-saccharic acid 1,4-lactone (IC50 = 45.75 ± 2.16 µM). To predict the binding mode of the substrate and β-glucuronidase, in silico study was performed. Conclusively, this study has identified a potent β-glucuronidase inhibitor that deserves to be further studied for the development of pharmaceutical products. 相似文献
5.
Lubna Atta Ruqaiya Khalil Khalid Mohammed Khan Moatter Zehra Faiza Saleem Mohammad Nur-e-Alam Zaheer Ul-Haq 《Molecules (Basel, Switzerland)》2022,27(4)
Dental caries, a global oral health concern, is a biofilm-mediated disease. Streptococcus mutans, the most prevalent oral microbiota, produces extracellular enzymes, including glycosyltransferases responsible for sucrose polymerization. In bacterial communities, the biofilm matrix confers resistance to host immune responses and antibiotics. Thus, in cases of chronic dental caries, inhibiting bacterial biofilm assembly should prevent demineralization of tooth enamel, thereby preventing tooth decay. A high throughput screening was performed in the present study to identify small molecule inhibitors of S. mutans glycosyltransferases. Multiple pharmacophore models were developed, validated with multiple datasets, and used for virtual screening against large chemical databases. Over 3000 drug-like hits were obtained that were analyzed to explore their binding mode. Finally, six compounds that showed good binding affinities were further analyzed for ADME (absorption, distribution, metabolism, and excretion) properties. The obtained in silico hits were evaluated for in vitro biofilm formation. The compounds displayed excellent antibiofilm activities with minimum inhibitory concentration (MIC) values of 15.26–250 µg/mL. 相似文献
6.
M. Emin Erdogan Ihsan T. Gürgöze 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1969,20(5):785-790
Résumé Dans ce travail, on présente une solution du problème de l'écoulement d'un fluide dipolaire entre deux plaques parallèles, dont l'une est en mouvement et l'autre fixe, en présence d'un gradient de pression. On trouve qu'il n'y a pas d'effet dipolaire sur l'écoulement si le gradient de pression n'est pas appliqué, et que pour un fluide dipolaire avec =0, étant le rapport entre l'espace des deux plaques et la constante dipolaire du fluide, le profil de vitesse n'est pas affecté par le gradient de pression. 相似文献
7.
Suzuki-Miyaura cross-coupling reactions of tetrabromo-p-benzoquinone provide a convenient approach to tetraaryl-p-benzoquinones. 相似文献
8.
Rasheed AhmadKhera Rasheed Ahmad Ihsan Ullah Obaid‐Ur‐Rahman Abid Olumide Fatunsin Muhammad Sher Alexander Villinger Peter Langer 《Helvetica chimica acta》2010,93(9):1705-1715
2‐Aryl‐2,3‐dihydro‐4H‐pyran‐4‐ones were prepared in one step by cyclocondensation of 1,3‐diketone dianions with aldehydes. The use of HCl (10%) for the aqueous workup proved to be very important to avoid elimination reactions of the 5‐aryl‐5‐hydroxy 1,3‐diones formed as intermediates. The TiCl4‐mediated cyclization of a 2‐aryl‐2,3‐dihydro‐4H‐pyran‐4‐one with 1,3‐silyloxybuta‐1,3‐diene resulted in cleavage of the pyranone moiety and formation of a highly functionalized benzene derivative. 相似文献
9.
Asma Rehman Muhammad Irfan Majeed Ayesha Ihsan Syed Zajif Hussain Saif-ur-Rehman Muhammad Afzal Ghauri Zafar M. Khalid Irshad Hussain 《Journal of nanoparticle research》2011,13(12):6747-6754
Abstract
A simple and environmentally benign green method is reported to decorate growing fungal hyphae with high loading of gold nanoparticles, which were initially produced using aqueous tea extract as a sole reducing/stabilizing agent. Inoculation of fungal spores in aqueous suspension of nanoparticles led to the growth of intensely red-coloured fungal hyphae due to the accumulation of gold nanoparticles. Heat treatment of these hybrid materials led to the formation of porous gold microwires. This report is thus an interesting example of using green and sustainable approach to produce nanostructured materials which have potential applications in catalysis, sensing and electronics. 相似文献10.