Beyond nanopowders: Hydrogen and formate are produced through the oxidation of alkaline HCHO by CuO microparticles. The Cu microparticles formed in the purely electrochemical reduction of CuO preserve the morphology of CuO (left‐hand image: CuO; right‐hand image: Cu formed in the reduction of CuO by alkaline HCHO) and can be permeated by a gas. They react more efficiently than Cu nanoparticles with air to restore CuO.
The use of DNA as a molecular wire in nanoscale electronic architectures would greatly benefit from its capability of sequence-specific self-assembly. Although single electrons and positive charges have been shown to be transmitted by natural DNA over a distance of several base pairs, the high ohmic resistance of unmodified oligonucleotides imposes a serious obstacle. Exchanging some or all of the Watson–Crick base pairs in DNA by metal complexes may solve this problem and evolve DNA-like materials with superior conductivity for future nano-electronic applications. The so-called metal–base pairs are formed from suitable transition metal ions and ligand-like nucleosides which are introduced into both of the two pairing strands by automated DNA synthesis. This review illustrates the basic concepts of metal–base pairing and highlights recent developments in the field. 相似文献
Changeable Silly Putty is a thermochromic material. It changes color due to a change in temperature. This paper describes advanced experiments designed to find the mechanism of the color change, provides a discussion of proposed mechanisms, and describes three experiments using Changeable Silly Putty that are suitable for young children. 相似文献
In this paper we present a simulated annealing approach for the gas network optimization problem. A gas network consists of
a set of pipes to transport the gas from the sources to the sinks whereby gas pressure gets lost due to friction. Further
on there are compressors, which increase gas pressure, and valves. The aim is to minimize fuel gas consumption of the compressors
whereas demands of consumers have to be satisfied. The problem of transient (time-dependent) optimization of gas networks
results in a highly complex mixed integer nonlinear program. We relax the equations describing the gas dynamic in pipes by
adding these constraints combined with appropriate penalty factors to the objective function. A suitable neighborhood structure
is developed for the relaxed problem where time steps as well as pressure and flow of the gas are decoupled. Our approach
convinces with flexibility and very good computational results. 相似文献
The use of lipases as biocatalysts in ester synthesis has been the object of growing interest, owing to the importance of
esters as emulsifiers, intermediates to produce oleochemicals, and fuel alternatives. We consider in this report the application
of lipases in the ethanolysis of palm and palm kernel oils to produce fatty-acid esters, using n-hexane assolvent. In order
to maximize ester production, wea dopted a Taguchi design and built an empirical model. Using this procedure, we determined
the optimal condition for each system and established the influence of process variables in the conversion. 相似文献
Lipophilic nucleic acids have become a versatile tool for structuring and functionalization of lipid bilayers and biological membranes as well as cargo vehicles to transport and deliver bioactive compounds, like interference RNA, into cells by taking advantage of reversible hybridization with complementary strands. This contribution reviews the different types of conjugates of lipophilic nucleic acids, and their physicochemical and self-assembly properties. Strategies for choosing a nucleic acid, lipophilic modification, and linker are discussed. Interaction with lipid membranes and its stability, dynamic structure and assembly of lipophilic nucleic acids upon embedding into biological membranes are specific points of the review. A large diversity of conjugates including lipophilic peptide nucleic acid and siRNA provides tailored solutions for specific applications in bio- and nanotechnology as well as in cell biology and medicine, as illustrated through some selected examples. 相似文献
Specific targeting and controlled release are crucial factors in the administration of drugs and therapeutic biomolecules. It has been shown that drug delivery systems can significantly benefit of the introduction of superparamagnetic nanoparticles in terms of both targeting and controlled release. Magnetic gradients can be used to target therapeutics to specific regions, while alternating magnetic fields produce frequency-dependent effects at the nanoparticle level. This review reports on the latest developments of multifunctional systems based on magnetic nanoparticles where the release of drugs and/or biomolecules is triggered by the application of an external magnetic field. The potentials of these systems are presented through examples in the fields of surface functionalized magnetic nanoparticles, magnetic polymer nanocomposites and magnetoliposomes. Recent results suggest the importance of integrating multiple functions within a single nanostructured device in order to successfully transport, localize and release drugs and biomolecules. 相似文献