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An extremely simple biomimetic oxidation system, consisting of mixing metal complexes of amphiphilic corroles with serum albumins, utilizes hydrogen peroxide for asymmetric sulfoxidation in up to 74% ee. The albumin-conjugated manganese corroles also display catalase-like activity, and mechanistic evidence points toward oxidant-coordinated manganese(III) as the prime reaction intermediate. 相似文献
43.
This paper describes the preparation for the first time of lipobead-based micrometric fluorescence biosensors and the optimization of their analytical properties. The study focused on the well-established urea biosensors as a model system. Fluorescence-sensing lipobeads were prepared by coating carboxyl-functionalized silica microspheres with phospholipids. The enzyme urease and the pH indicator fluorescein-5-thiosemicarbazide were then attached covalently to the phospholipid membrane of the lipobeads. Urease converts urea to ammonia, which results in a pH increase in the analyte solution and to a urea concentration-dependent increase in the fluorescence intensity of the sensing lipobeads. Previous fluorescence-sensing lipobeads were synthesized by coating polystyrene particles with a phospholipid membrane. The membrane was physically attached to the particles and the fluorophores were entrapped in the membrane. In this study, we prepared improved fluorescence-sensing lipobeads by utilizing covalent chemistry to bind the phospholipid membrane to the silica particles and the fluorophores to the membrane. This led to improvement in the stability of the newly developed urea-sensing lipobeads compared to previously developed miniaturized fluorescence biosensors. 相似文献
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A method for depth sensing based on sensing the visibility associated with the coherence function of a laser source is presented. The setup is based on an electronic speckle pattern interferometric (ESPI) setup, where the object depth is encoded into the amplitude of the interference pattern without the need for depth scanning. After performing phase-shifting method, the object three-dimensional (3-D) shape is reconstructed by means as a range image from the visibility of the image set of interferograms and where each gray level represents a given object depth. Experimental results validate the proposed approach for reflective diffuse objects at different measurement distances. 相似文献
47.
Zeev Nutov 《Discrete Applied Mathematics》2013,161(13-14):2101-2106
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Haber A Mahammed A Fuhrman B Volkova N Coleman R Hayek T Aviram M Gross Z 《Angewandte Chemie (International ed. in English)》2008,47(41):7896-7900
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Radzishevsky IS Kovachi T Porat Y Ziserman L Zaknoon F Danino D Mor A 《Chemistry & biology》2008,15(4):354-362
We describe structure-activity relationships that emerged from biophysical data obtained with a library of antimicrobial peptide mimetics composed of 103 oligoacyllysines (OAKs) designed to pin down the importance of hydrophobicity (H) and charge (Q). Based on results obtained with OAKs displaying minimal inhibitory concentration < or = 3 microM, the data indicate that potent inhibitory activity of the gram-negative Escherichia coli and the gram-positive Staphylococcus aureus required a relatively narrow yet distinct window of HQ values where the acyl length played multiple and critical roles, both in molecular organization and in selective activity. Thus, incorporation of long-but not short-acyl chains within a peptide backbone is shown to lead to rigid supramolecular organization responsible for poor antibacterial activity and enhanced hemolytic activity. However, sequence manipulations, including introduction of a tandem lysine motif into the oligomer backbone, enabled disassembly of aggregated OAKs and subsequently revealed tiny, nonhemolytic, yet potent antibacterial derivatives. 相似文献
50.
Palmer JH Day MW Wilson AD Henling LM Gross Z Gray HB 《Journal of the American Chemical Society》2008,130(25):7786-7787
This work reports the synthesis and full characterization of 5,10,15-tris-pentafluorophenylcorrolato-iridium(III) bis-trimethylamine 1 and its octabromo derivative 2. The corrole is planar in both cases (the mean deviation from the plane is as low as 0.0371 A for 1 and 0.0325 A for 2), the UV-vis spectra display a split Soret band with a shoulder attributable to an MLCT transition, and cyclic voltammetry reveals that the iridium(II) oxidation state cannot be accessed, while the oxidation to formal iridium(IV) complexes is achieved at much lower potentials than in other coordination environments. 相似文献