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121.
Markov J Fischer R Wagner H Noormofidi N Baumgartner J Marschner C 《Dalton transactions (Cambridge, England : 2003)》2004,(14):2166-2169
Salt elimination reactions of tris(trimethylsilyl)silyl potassium (1), and two 1,4-dipotassiooligosilanes (3, 5) with 2,2,6,6-tetramethylpiperidinodichloroborane and diethylaminodichlorophosphane have generated open (2), cyclic (4) and bicyclic (6) bora- and phosphaoligosilanes. A monosilylated phosphane and the two five-membered cyclosilanes have been subjected to single crystal X-ray diffraction analysis. 相似文献
122.
Flows on (or variations of) discrete curves in
give rise to flows on a subalgebra of functions on that curve. For a special choice of flows and a certain subalgebra this is described by the Toda lattice hierarchy. Here it is shown that the canonical symplectic structure on
, which can be interpreted as the phase space of closed discrete curves in
with length N, induces Poisson commutation relations on the above-mentioned subalgebra which yield the tri-Hamiltonian poisson structure of the Toda lattice hierarchy. 相似文献
123.
Bege N Renette T Jansch M Reul R Merkel O Petersen H Curdy C Müller RH Kissel T 《Macromolecular bioscience》2011,11(7):897-904
The goal of this study was to investigate the suitability of poly(ethylene carbonate) (PEC) nanoparticles as a novel drug delivery system, fulfilling the requirements for a long circulation time. Particles were obtained with a narrow size distribution and nearly neutral zeta potential. Adsorption studies with human plasma proteins revealed that PEC nanoparticles bind much less proteins in comparison to polystyrene (PS) nanoparticles. Cell experiments with fluorescently labeled PEC showed no uptake of the nanoparticles by macrophages. These novel PEC nanospheres with their unique surface properties are a promising candidate for long circulating drug delivery systems in vivo. 相似文献
124.
An artificial operon was synthesized, consisting of the genes for chorismate pyruvate-lyase of E. coli and for 4-hydroxybenzoate 3-hydroxylase of Corynebacterium cyclohexanicum. This operon, directing the biosynthesis of 3,4-dihdroxybenzoate, was expressed in the heterologous expression host Streptomyces coelicolor M512, together with a modified biosynthetic gene cluster for the aminocoumarin antibiotic clorobiocin. The resulting strain produced a clorobiocin derivative containing a 3,4-dihdroxybenzoyl moiety. Its structure was confirmed by MS and NMR analysis, and it was found to be a potent inhibitor of the gyrases from Escherichia coli and Staphylococcus aureus. Bioassays against different E. coli mutants suggested that this compound is actively imported by catechol siderophore transporters in the cell envelope. This study provides an example of the structure of a natural product that can be rationally modified by synthetic biology. 相似文献
125.
M-TBA (4-methoxy-3,30,5,50-tetra-tert-butylazobenzene) adsorbed on a gold (111) surface was found to form four different polymorphs, two of which isomerizable at -1.7 V, but with a low propensity for further isomerisation of nearby molecules (C. Dri, M. V. Peters, J. Schwarz, S. Hecht, L. Grill, Nat. Nanotechnol., 2008, 3, 649-653). Atomistic simulations investigate the origin of the effects. 相似文献
126.
Ricardo NM Ricardo NM Costa Fde M Chaibundit C Portale G Hermida-Merino D Burattini S Hamley IW Muryn CA Nixon SK Yeates SG 《Journal of colloid and interface science》2011,364(2):482-489
Thermodynamic and kinetics studies for adsorption of Pt ions complexes from the chloride solutions obtained by leaching chlorinated spent automotive catalysts on anionic exchange resin Diaion WA21J were carried out. It was found that only Si, Pt, Rh and Pd from the solution were selectively adsorbed on the resin Diaion WA21J more strongly. The adsorption equilibrium time for Pt ions was about 20 h. The isothermal adsorption of Pt ions was found to fit Langmuir, Freundlich and DKR models. The maximum monolayer adsorption capacities Q(max) and X(m) of Pt ions on the resin based on Langmuir and DKR model were 4.85, 5.36 and 5.69 mg/g as well as 5.01, 5.63 and 5.98 mg/g for temperatures 18°C, 28°C and 40°C, respectively. The apparent adsorption energy E(ad) based on DKR model were -11.79, -11.04 and -11.04 kJ/mol for the temperatures 18°C, 28°C and 40°C, respectively. Ion exchange was the mechanism involved in the adsorption process. The adsorption of Pt ions on the resin underwent pseudo-first-order kinetic process, and the apparent adsorption activation energy E(a,1) was 12.6 kJ/mol. The intraparticle diffusion of Pt ions was a main rate-controlling step in most of time of adsorption process. 相似文献
127.
César H. Lenzi Nadja S. Magalhães César A. Costa Rubens M. Marinho Jr Helmo A. B. Araújo Odylio D. Aguiar 《General Relativity and Gravitation》2008,40(1):183-190
The direct detection of gravitational waves will provide valuable astrophysical information about many celestial objects.
Also, it will be an important test to general relativity and other theories of gravitation. The gravitational wave detector
SCHENBERG has recently undergone its first test run. It is expected to have its first scientific run soon. In this work the
data analysis system of this spherical, resonant mass detector is tested through the simulation of the detection of gravitational
waves generated during the inspiralling phase of a binary system. It is shown from the simulated data that it is not necessary
to have all six transducers operational in order to determine the source’s direction and the wave’s amplitudes. 相似文献
128.
An iron-rich aluminosilicate liquid is studied in different atmospheres by using differential scanning calorimetry. The results show that the oxidation state of iron and the maximum temperature of the scan have an effect on the liquid structure and on the crystallization behavior of the liquid during both cooling and reheating processes. Increase in Fe2+/Fe3+ enhances crystallization and favors formation of a stable crystal structure. The structural order conserved in the liquid is an intrinsic phenomenon, which is not related to the oxidation state of iron. 相似文献
129.
130.
Youxin Fu Jun.-Prof. Dr. Nadja A. Simeth Dr. Ryojun Toyoda Dr. Robert Brilmayer Prof. Dr. Wiktor Szymanski Prof. Dr. Ben L. Feringa 《Angewandte Chemie (International ed. in English)》2023,62(16):e202218203
Light-induced 9,10-phenanthrenequinone-electron-rich alkene ( PQ-ERA ) photocycloadditions are an attractive new type of photoclick reaction, featuring fast conversions and high biocompatibility. However, the tunability of the reaction was hardly investigated up to now. To this end, we explored the influence of substituents on both reaction partners and the reaction rate between the PQs and ERAs . We identified new handles for functionalization and discovered that using enamines as ERAs leads to drastically enhanced rates (>5400 times faster), high photoreaction quantum yields ( ΦP , up to 65 %), and multicolor emission output as well as a high fluorescence quantum yield of the adducts ( ΦF , up to 97 %). Further investigation of the photophysical and photochemical properties provided insights to design orthogonal reaction systems both in solution and on nanoparticle surfaces for ultrafast chemoselective functionalization by photoclick reactions. 相似文献