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21.
Andreas Christoforow Julian Wilke Aylin Binici Axel Pahl Claude Ostermann Sonja Sievers Herbert Waldmann 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(41):14857-14865
Natural products (NPs) inspire the design and synthesis of novel biologically relevant chemical matter, for instance through biology‐oriented synthesis (BIOS). However, BIOS is limited by the partial coverage of NP‐like chemical space by the guiding NPs. The design and synthesis of “pseudo NPs” overcomes these limitations by combining NP‐inspired strategies with fragment‐based compound design through de novo combination of NP‐derived fragments to unprecedented compound classes not accessible through biosynthesis. We describe the development and biological evaluation of pyrano‐furo‐pyridone (PFP) pseudo NPs, which combine pyridone‐ and dihydropyran NP fragments in three isomeric arrangements. Cheminformatic analysis indicates that the PFPs reside in an area of NP‐like chemical space not covered by existing NPs but rather by drugs and related compounds. Phenotypic profiling in a target‐agnostic “cell painting” assay revealed that PFPs induce formation of reactive oxygen species and are structurally novel inhibitors of mitochondrial complex I. 相似文献
22.
Aylin Sendemir Urkmez Sherrie G. Clark Matthew B. Wheeler Michael S. Goldwasser Russell D. Jamison 《Macromolecular Symposia》2008,269(1):100-105
Porous, 3D chitosan/biphasic calcium phosphate (BCP) scaffolds were used to prepare tissue engineering constructs for maxillofacial bone tissue reconstruction. Mesenchymal stem cells (MSC's) were seeded and cultured on clinically relevant sized scaffolds. In vitro engineered constructs facilitated the healing of mandibular defects in pigs if accompanied with delivery of basic fibroblast growth factor (bFGF). 相似文献
23.
Aylin akar-Deliormanl Erdal elik Mehmet Polat 《Colloids and surfaces. A, Physicochemical and engineering aspects》2008,324(1-3):159-166
Lead magnesium niobate (PMN) is a relaxor ferroelectric material and have widespread applications in the manufacture of multilayer electronic devices such as ceramic capacitors, actuators and transducers. The dielectric constant of this electrostrictive material is much higher than the well known ferroelectric barium titanate. However, aqueous processing of PMN is not investigated yet especially for the novel wet shaping fabrication. In this study, concentrated aqueous colloidal PMN gels have been designed to use in the robocasting process. Concentrated PMN suspensions were stabilized by polyacrylic acid and then gelation induced by changing the pH or ionic strength of the suspension or by addition of a cationic polyelectrolyte to the system. Through this procedure it was essential to understand the solid–liquid transition under shear to explore the feasibility of forming without excessive use of polymers. Therefore, rheological response of the samples having a gel network was investigated. Results showed that gelation induced by cationic polyethylene imine or by multivalent salts were successful methods in preparation of PMN gels. However, gelation induced by changing the pH of the suspension was challenging due to ion dissolution from PMN surface. 相似文献
24.
Basu and Basu (Statistica Sinica 8:841–860, 1998) have proposed an empty cell penalty for the minimum power-divergence estimators
which can lead to improvements in the small sample properties of these estimators. In this paper, we study the small and moderate
sample performances of the ordinary and penalized minimum power-divergence estimators in terms of efficiency and robustness
for the log-linear models in two-way contingency tables under the assumptions of multinomial sampling. Calculations made by
enumerating all possible sample combinations show that the penalized estimators are competitive with the ordinary estimators
for the moderate samples and definitely better for the smallest sample considered for both efficiency and robustness under
the considered models. The results also reveal that the bigger the main effects the more need for penalization. 相似文献
25.
Okan Zafer Yeşilel Aylin Mutlu Güneş Günay Necmettin Caner Halis Ölmez Orhan Büyükgüngör 《Journal of chemical crystallography》2012,42(5):519-523
Abstract
A novel Cu(II)-pyrazine-2,3-dicarboxylate complex with monoethanolamine ligand (mea), [Cu(μ3-pzdc)(mea)]n (1), has been synthesized and characterized by elemental, spectral (IR and UV–Vis.) and thermal analyses. The molecular structure of polynuclear complex has been determined by the single crystal X-ray diffraction technique. The pyrazine-2,3-dicarboxylate dianion exhibits tetradentate-μ3 bridging ligand through three carboxylate oxygens and one nitrogen atom. The complex contains two copper(II) ions that exhibit two different coordination environments with two mea, two pzdc ligands, respectively. The Cu1(II) ion is coordinated by two carboxylate oxygen atoms, two N atoms and two O atoms of symmetry related carboxylate group, forming a distorted octahedral geometry, while Cu2(II) ion is coordinated by two bidentate mea ligands and remaining two coordination sites of distorted octahedral geometry are occupied by two carboxylate oxygen atoms of neighboring Cu1 molecule. Thermal analysis property and thermal decomposition mechanism of complex have been investigated by using thermal analyses techniques (TG, DTG and DTA). 相似文献26.
27.
?ule ?ahin Ün Aylin UsluSerkan Ye?ilot ?lker ÜnBünyemin Ço?ut Fatma YukselAdem K?l?ç 《Polyhedron》2011,30(9):1587-1594
Hexachlorocyclotriphosphazene N3P3Cl6 and gem-disubstituted cyclotriphosphazene derivatives N3P3Cl4X2 (X = Ph, PhS, PhNH) were reacted with N-methyl-1,3-propanediamine and 3-amino-1-propanol to give compounds (9a-12a, 9b-12b) which exist as cis and trans geometric isomers and are two different racemic isomers, respectively to describe the stereogenic properties of a series of chiral cyclotriphosphazene compounds with two different centres of chirality. The geometric isomers were separated by column chromatography on silica gel and analysed by elemental analysis, mass spectrometry, and 31P and 1H NMR spectroscopies, and also the geometric forms (cis or trans) of 9b, 10a, 11a, 11b and 12a have been determined by the X-ray crystallography. The enantiomers of all racemic compounds have been analysed by the changes in 31P NMR spectra on addition of a Chiral Solvating Agent (CSA), (R)-(+)-2,2,2-trifluoro-1-(9′-anthryl)ethanol. On the other hand, the racemic forms of chiral cyclotriphosphazene derivatives have been confirmed by contribution of chiral HPLC methods which have been developed for this study. 相似文献
28.
Resat H Sungur FA Baginski M Borowski E Aviyente V 《Journal of computer-aided molecular design》2000,14(7):689-703
Even though it is highly toxic, Amphotericin B (AmB), an amphipathic polyene macrolide antibiotic, is used in the treatment of severe systemic fungal infections as a life-saving drug. To examine the influence of conformational factors on selective toxicity of these compounds, we have investigated the conformational properties of five AmB amide derivatives. It was found that the extended conformation with torsional angles (,)=(290°,180° ) is a common minimum of the potential energy surfaces (PES) of unsubstituted AmB and its amide derivatives. The extended conformation of the studied compounds allows for the formation of an intermolecular hydrogen bond network between adjacent antibiotic molecules in the open channel configuration. Therefore, the extended conformation is expected to be the dominant conformer in an open AmB (or its amide derivatives) membrane channel. The derivative compounds for calculations were chosen according to their selective toxicity compared to AmB and they had a wide range of selective toxicity. Except for two AmB derivatives, the PES maps of the derivatives reveal that the molecules can coexist in more than one conformer. Taking into account the cumulative conclusions drawn from the earlier MD simulation studies of AmB membrane channel, the results of the potential energy surface maps, and the physical considerations of the molecular structures, we hypothesize a new model of structure-selective toxicity of AmB derivatives. In this proposed model the presence of the extended conformation as the only well defined global conformer for AmB derivatives is taken as the indicator of their higher selective toxicity. This model successfully explains our results. To further test our model, we also investigated an AmB derivative whose selective toxicity has not been experimentally measured before. Our prediction for the selective toxicity of this compound can be tested in experiments to validate or invalidate the proposed model. 相似文献
29.
Impedimetric Aptasensor Based on Disposable Graphite Electrodes Developed for Thrombin Detection 下载免费PDF全文
Ece Eksin Arzum Erdem Ayben Pınar Kuruc Hilal Kayi Aylin Öğünç 《Electroanalysis》2015,27(12):2864-2871
The impedimetric aptasensor for Thrombin (THR) was developed for the first time herein by measuring changes at the charge‐transfer resistance, Rct upon to protein? aptamer complex formation. After covalent activation of pencil graphite electrode (PGE) surface using covalent agents, amino linked aptamer (APT) was immobilized onto activated PGE surface. Then APT‐THR interaction was explored by electrochemical impedance spectroscopy (EIS). After the optimization of experimental conditions (e.g., APT and THR concentration, immobilization and interaction times), the selectivity of impedimetric aptasensor was tested in the presence of other biomolecules: factor Va and bovine serum albumine (BSA) both in buffer media, or in diluted fetal bovine serum (FBS). 相似文献
30.
Simon J. Coles Michael B. Hursthouse ?ule ?ahin Aylin Uslu 《Journal of organometallic chemistry》2007,692(13):2811-2821
Derivatives of the tri-spirane pentaerythritoxy-cyclophosphazene compound 1 have been used to investigate the stereogenic properties of spiranes combined with either one or two conventional centres of chirality. In compound 1, the two inner rings are carbocyclic and symmetrical and the two outer rings are cyclotriphosphazenes substituted in different positions to provide the conventional centres of chirality. Reaction of 1 in a 1:1 molar ratio with the unsymmetrical dinucleophilic reagent, 1,3-aminopropanol, gave the mono-spiro substituted derivative 2, which was shown to exist as a racemate by X-ray crystallography and 31P NMR spectroscopy on addition of a chiral solvating agent (CSA). Reaction of 1 with 1,3-aminopropanol in a 1:2 molar ratio gave three diastereoisomeric di-mono-spiro products 3a-3c, which were all shown to be racemates using a combination of X-ray crystallography (3a, 3c) and 31P NMR spectroscopy on addition of a CSA (3b), thus proving the case of the stereogenic properties of spirane molecules combined with two equivalent conventional centres of chirality. It is also shown by quantitative 31P NMR spectroscopy of the reaction mixture and by isolation of reaction products that the proportions of the diastereoisomers 3a:3b:3c are in approximate ratios of 1:2:1, respectively, and these results have been rationalised by analysis of the stereogenic properties of the series of reactions 1 → 2 → 3. 相似文献