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961.
Szymańska I Stobiecka M Orlewska C Rohand T Janssen D Dehaen W Radecka H 《Langmuir : the ACS journal of surfaces and colloids》2008,24(19):11239-11245
In the work presented, thiol- and COOH-terminated dipyrromethene derivatives have been applied for gold electrode modification. Dipyrromethene deposited onto a solid support, after binding Cu2+, can act as a redox active monolayer. The complexation of Cu(II) ions has been performed on the surface of gold electrodes modified with dipyrromethene. The characterization of dipyrromethene-Cu(II) self-assembled monolayers (SAMs) has been done by cyclic voltammetry (CV), wettability contact angle measurements, and atomic force microscopy (AFM). The new electroactive monolayer could be applied for the immobilization of proteins and ssDNA or for electrochemical anion sensing without redox markers in the solution. 相似文献
962.
Marcin Kwit Dr. Jacek Gawronski Prof. Dr. Derek R. Boyd Prof. Dr. Narain D. Sharma Dr. Magdalena Kaik Dr. Rory A. More O'Ferrall Prof. Dr. Jaya S. Kudavalli Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(36):11500-11511
cis‐Dihydrodiol metabolites have been isolated from naphthalene and six 2‐substituted naphthalene substrates. Their structures and absolute configurations have been determined by a combination of calculated (TDDFT) and experimentally based circular dichroism (CD) and optical rotation (OR) methods. The “inverse” styrene helicity rule is shown to be incorrect for the interpretation of the CD spectra of cis‐dihydrodiols. A striking conclusion is that CD spectra correlate directly with the helicity of the styrene chromophore: that is, the sign of the long‐wavelength Cotton effect is identical with the sign of styrene torsion angle, whereas the OR sign is dependent on the absolute configuration of the allylic carbon atom. The results demonstrate that a predictive model previously used for the determination of preferred regio‐ and stereoselectivity associated with TDO‐catalyzed cis‐dihydroxylation of substituted benzene substrates can now be successfully extended to substituted naphthalene substrates. 相似文献
963.
Shcharbin D Ottaviani MF Cangiotti M Przybyszewska M Zaborski M Bryszewska M 《Colloids and surfaces. B, Biointerfaces》2008,63(1):27-33
Dendrimers are a new class of nanotechnological polymers suitable for drug targeting, microarray systems or detoxication. The present study is devoted to a detailed analysis of binding between PAMAM dendrimers and bovine serum albumin (fatty acid free or loaded with oleic, linoleic, oleic+linoleic or oleic+linoleic+arachodonic acids) by measuring zeta-potential, fluorescence quenching, fluorescence anisotropy and electron paramagnetic resonance. Addition of PAMAM G2 and G6 dendrimers to protein solutions resulted in attachment to the protein molecule. The PAMAM dendrimers also competed with BSA for fatty acids if two or three fatty acids were loaded per protein. This can lead to the extraction of fatty acids from BSA to the PAMAM dendrimer. 相似文献
964.
965.
The interactions of CrO(4) (2-) and Cr(3+) with nucleosides studied by electrospray ionization mass spectrometry (ESI-MS) are reported. In water, the nucleosides which do not contain the NH(2) group form the unstable [M+HCrO(4)](-) anion. In the presence of a reducing agent, namely methanol, chromate anion forms stable complexes with nucleosides, [M+CH(3)CrO(4)](-) anions. The fragmentation of [M+CH(3)CrO(4)](-) anions involve elimination of the methanol molecule. Chromium cation-nucleoside complexes were not observed in water. In methanol solutions, adenosine and cytidine form [(M-H)+CrOCH(3)](+) and [(M-H)(2)+Cr](+) ions. Most probably, deprotonated imine tautomers form complexes in which a metal cation is simultaneously coordinated by two nitrogen atoms. Complexes containing chloride anions and a few methanol molecules were observed for other nucleosides. Guanosine and inosine form doubly charged ions of the type [M(2)+CrOCH(3)](2+) that probably contain a bond between the oxygen atom and the chromium cation, (HN(1)--C(6)==O)(2) (....)Cr(3+)). 相似文献
966.
In this study, the hydration of a model Lennard-Jones solute particle and the analytical approximations of the free energy of hydration as functions of solute microscopic parameters are analyzed. The control parameters of the solute particle are the charge, the Lennard-Jones diameter, and also the potential well depth. The obtained multivariate free energy functions of hydration were parametrized based on Metropolis Monte Carlo simulations in the extended NpT ensemble, and interpreted based on mesoscopic solvation models proposed by Gallicchio and Levy [J. Comput. Chem. 25, 479 (2004)], and Wagoner and Baker [Proc. Natl. Acad. Sci. U.S.A. 103, 8331 (2006)]. Regarding the charge and the solute diameter, the dependence of the free energy on these parameters is in qualitative agreement with former studies. The role of the third parameter, the potential well depth not previously considered, appeared to be significant for sufficiently precise bivariate solvation free energy fits. The free energy fits for cations and neutral solute particles were merged, resulting in a compact manifold of the free energy of solvation. The free energy of hydration for anions forms two separate manifolds, which most likely results from an abrupt change of the coordination number when changing the size of the anion particle. 相似文献
967.
Wanda Ziemkowska Magdalena Metelska Romana Anulewicz-Ostrowska 《Journal of organometallic chemistry》2008,693(3):369-373
A reaction of Me3Al with 2,2′-methylene-p-chloro-bisphenol in Et2O yielded Me5Al3[OC6H3(Cl)CH2C6H3(Cl)O]2 (1). Compound 1 reacted with 2,2′-di(hydroxymethyl)biphenyl to form Me3Al3[OC6H3(Cl)CH2C6H3(Cl)O](OCH2C12H8CH2O)2 (2) bearing two kinds of diolate ligands. Compound 2 was structurally characterised. 相似文献
968.
TGA investigations on the thermal degradation of isotactic polypropylene-vapor grown carbon nanofibers composites in nitrogen are reported. The mass evolution as a function of temperature is a single sigmoid for both polypropylene and polypropylene loaded with carbon nanofibers. The inflection temperature of these sigmoids increases as the concentration of carbon nanofibers is increased. The width of the degradation process narrows as the concentration of carbon nanofibers is increased due to a better homogenization of the local temperature provided by the high thermal conductivity of carbon nanofibers. Thermogravimetric analysis data indicate the formation of polymer-carbon nanofiber interface. Based on TGA data, a two-layer structure is proposed for carbon nanofibers-polypropylene interface. The external layer is soft and has a thickness of about 102 nm that confines most polymer molecules in interaction with nanofibers. The core layer is rigid and has a thickness of the order of few nanometers. 相似文献
969.
Thermostated micro thin-layer chromatography was applied for separation and quantification studies of Spirulina maxima dyes isolated from pharmaceutical formulation by a simple one-step liquid extraction. The isolation process was performed using a number of liquids, including water; 10 mM water solutions of native alpha-, beta-, and gamma-cyclodextrin and their hydroxypropyl derivatives; and a number of common organic liquids characterized by different polarity, namely, methanol, ethanol, 1-propanol, 2-propanol, acetonitrile, acetone, tetrahydrofuran, dichloromethane, toluene, and n-hexane. Chromatographic studies were performed on RP18W plates working inside a small thermostated horizontal chamber allowing a development distance of 45 mm. Using a mobile phase consisting of acetone-n-hexane (30 + 70, v/v) and 40 degrees C separation temperature, plate peak capacity of at least 15 spots/lane and developing time <5 min were obtained. Validation data indicated that under such conditions, with an office scanner used for chromatogram digitalization, spot quantification could be accurately performed within an analyte mass range of 2 factors. The raw quantitative data obtained from microchromatograms acquired under visible light conditions were explored using cluster analysis and principal components analysis. Chemometric investigations revealed that the best extraction liquids for isolation of dye mixtures from Spirulina samples were methanol, ethanol, tetrahydrofuran, and dichloromethane. Moreover, it was found that the liquids' parachor values could be used for estimation of the dye extraction efficiency from complex samples. 相似文献
970.
MSc Daria B. Wojtala Sc.D. Urszula K. Komarnicka Sc.D. Agnieszka Kyzioł Dr. Sandra Kozieł BSc Magdalena Szmitka MSc Mateusz Słowikowski MSc Julia Kulczyńska Prof. Grażyna Stochel 《欧洲无机化学杂志》2023,26(33):e202300515
Two piano-stool ruthenium(II) complexes Ru(η6-p-cymene)Cl2PPh2CH2OH ( RuPOH ) and Ru(η6-p-cymene)Cl2P(p-OCH3Ph)2CH2OH ( RuMPOH ) and two half-sandwich iridium(III) complexes Ir(η 5-Cp*)Cl2PPh2CH2OH ( IrPOH ) and Ir(η 5-Cp*)Cl2P(p-OCH3Ph)2CH2OH ( IrMPOH ) have been studied in terms of potential anticancer activity on previously selected cell line (human lung adenocarcinoma). Based on experimental results obtained in monoculture in vitro model mechanistic considerations on the possible cellular modes of action have been carried out. ICP-MS analysis revealed the higher cellular uptake for less hydrophobic Ir(III) complexes in comparison to the corresponding Ru(II) compounds. Cytometric analysis showed a predominance of apoptosis over the other types of cell death for all complexes. The apoptotic pathway was confirmed by a decrease in mitochondrial membrane potential and the activation of caspases-3/9 for both Ru(II) and Ir(III) complexes. It was concluded that in the case of Ru(II) complexes the intense ROS generation is mainly responsible for the resulting cytotoxicity. The corresponding Ir(III) complexes trigger simultaneously at least three different cytotoxic pathways i. e., depletion of mitochondrial potential, activation of caspases-dependent apoptosis, and ROS-associated oxidation. Thus, it can be assumed that the final accumulation of toxic effects over time via parallel activation of different pathways results in the highest cytotoxicity in vitro exhibited by Ir(III) complexes when compared with Ru(II) complexes. 相似文献