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71.
Andrei S. Chikunov Prof. Oxana P. Taran Dr. Inna A. Pyshnaya Prof. Valentin N. Parmon 《Chemphyschem》2019,20(3):410-421
Colloidal catalysts for oxidation of water to dioxygen, which are stable on storage and under the reaction conditions, are synthesized based on CoIII, MnIII, FeIII and CuII hydroxides. Stabilization of the colloids with dextrated starch allows the process of hydroxide ageing to be stopped at the stage of the formation of primary nuclei (ca. 2–3 nm from transmission electron microscopy data). Molecular mechanics and dynamic light scattering studies indicate a core-shell type structure of the catalysts, where the hydroxide core is stabilized by the molecular starch network (ca. 5–7 nm). The colloidal catalysts are highly efficient in oxidizing water with one electron oxidant Ru(bpy)33+ at pH 7 to 10. The influence of pH, catalyst concentration, and buffer nature on the oxygen yield is studied. The maximal yields are 72, 53, and 78 % over Fe-, Mn- and Co-containing catalysts, respectively, and turnover numbers are 7.8; 54 and 360, respectively. The Cu-containing catalyst is poorly effective to the water oxidation (the maximal yield is 28 % O2). The synthesized catalysts are of interest for stopped-flow kinetic studies of the mechanism of the water oxidation and as precursors for anchoring nanosized hydroxides onto various supports in order to develop biomimetic systems for artificial photosynthesis. 相似文献
72.
Abramova E. S. Balandin S. F. Donchenko V. A. Myshkin V. F. Potekaev A. I. Khan V. A. 《Russian Physics Journal》2020,63(2):332-337
Russian Physics Journal - The paper deals with the propagation of the powerful laser beam in gas-dispersion systems and atmospheric aerosol background, which is accompanied by a wide spectrum of... 相似文献
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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
77.
Kogan A Popov I Uvarov V Cohen S Aserin A Garti N 《Langmuir : the ACS journal of surfaces and colloids》2008,24(3):722-733
Crystallization of carbamazepine (CBZ), an antiepileptic drug, precipitated from confined spaces of nonionic microemulsions was investigated. The study was aimed to correlate the structure of the microemulsion [water-in-oil (W/O), bicontinuous, and oil-in-water (O/W)] with the crystalline structure and morphology of solid CBZ. The precipitated CBZ was studied by DSC, TGA, powder XRD, single-crystal XRD, SEM, and optical microscopy. The results suggest that the microstructure of the microemulsions influences the crystallization process and allows crystallizing polymorphs that exhibit different crystal structure and habits. W/O nanodroplets orient the crystallizing CBZ molecules to form a prismlike anhydrous polymorphic form with monoclinic unit cell and P21/n space group. Bicontinuous structures lead to platelike dihydrate crystals with orthorhombic unit cell and Cmca space group. The O/W nanodroplets cause the formation of needlelike dihydrate crystals with monoclinic unit cell and P21/c space group. The morphological features of solid CBZ remain predetermined by the basic symmetry and parameters of its unit cell. Precipitation of CBZ pseudopolymorphs from supersaturated microemulsion is discussed in terms of oriented attachment that provides perfect packing of numerous separately nucleated ordered nuclei of CBZ into microscale platelets and then into macroscopic crystals. Crystallization from microemulsion media enabling one to obtain the drug (CBZ) with predicted structure and morphology should be of great significance for pharmaceutical applications. 相似文献
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Agarose gel electrophoresis, a very routine procedure, requires molecular weight standards; these are usually manufactured from plasmid or viral DNA fragments, or more recently, from PCR products of defined sizes. We describe here the preparation of a molecular weight standard from a completely different DNA source - the uniquely organized genome of the beetle Tenebrio molitor. The standard can be used to accurately size DNAs between 150 and 4500 bp, a useful range of sizes for many agarose gel electrophoresis applications, including separation of PCR products and plasmid cloning targets. In addition, it is easy to prepare, inexpensive, and rivals the best of the commercial ladders. 相似文献
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Fakhrullin RF Vinter VG Zamaleeva AI Matveeva MV Kourbanov RA Temesgen BK Ishmuchametova DG Abramova ZI Konovalova OA Salakhov MK 《Analytical and bioanalytical chemistry》2007,388(2):367-375
We report the development of a novel quartz crystal microbalance immunosensor with the simultaneous measurement of resonance
frequency and motional resistance for the detection of antibodies to double-stranded DNA (dsDNA). The immobilization of poly(l-lysine) and subsequent complexation with DNA resulted in formation of a sensitive dsDNA-containing nanofilm on the surface
of a gold electrode. Atomic force microscopy has been applied for the characterization of a poly(l-lysine)–DNA film. After the blocking with bovine serum albumin, the immunosensor in flow-injection mode was used to detect
the antibodies to dsDNA in purified protein solutions of antibodies to dsDNA and to single-stranded DNA, monoclonal human
immunoglobulin G, DNase I and in blood serum of patients with bronchial asthma and systemic lupus erythematosus. Experimental
results indicate high sensitivity and selectivity of the immunosensor.
In memoriam Prof. Victor G. Vinter 相似文献