Improving solid-state NMR dipolar recoupling by optimal control

We present the first solid-state NMR experiments developed using optimal control theory. Taking heteronuclear dipolar recoupling in magic-angle-spinning NMR as an example, it proves possible to significantly improve the efficiency of the experiments while introducing robustness toward instrumental imperfections such as radio frequency inhomogeneity. The improvements are demonstrated by numerical simulations as well as practical experiments on a 13Calpha,15N-labeled powder of glycine. The experiments demonstrate a gain of 53% in the efficiency for 15N to 13Calpha coherence transfer relative to the typically double-cross-polarization experiments.     

Recent developments in isotachophoresis

This paper is summarizing the contributions to the analytical capillary isotachophoresis published during the period 1981-1984. It characterizes the present state of the method and covers theory, fundamental analytical aspects, instrumentation and applications. Special attention was payed to the fundamental analytical aspects, and a detailed discussion is given of the selection of electrolyte systems, stability of zones and separability of substances. The present commercial instrumentation is also briefly described.     

Pulsed DC magnetron sputtering of transparent conductive oxide layers

A comprehensive material study of different transparent conductive oxides （TCOs） is presented. The layers are deposited by pulsed direct current （DC） magnetron sputtering in an inline sputtering system. Indium tin oxide （ITO） films are studied in detail. The optimum pressure of 0.33 Pa （15Ar：202） produces a 300- nm thin film with a specific resistivity p of 2.2 × 10-6 Ωm and a visual transmittance of 81%. Alternatively, ZnO：A1 and ZnO：Ga layers with thicknesses of 200 and 250 nm are deposited with a minimum resistivity of 5.5× 10-6 and 6.8× 10-6Ωm, respectively. To compare the optical properties in the ultraviolet （UV） range, the optical spectra are modeled and the band gap is determined.     

Molecular electrocatalysis at soft interfaces

The fundamental aspects of electrochemistry at liquid-liquid interfaces are introduced to present the concept of molecular electrocatalysis. Here, a molecular catalyst is adsorbed at the interface to promote a proton coupled electron transfer reaction such as hydrogen evolution or oxygen reduction using lipophilic electron donors.     

Catalytic Functionalization of Indoles in a New Dimension

140 Years ago Adolf von Baeyer proposed the structure of a heteroaromatic compound which revolutionized organic and medical chemistry: indole. After more than a century, indole itself and the complexity of naturally occurring indole derivatives continue to inspire and influence developments in synthetic chemistry. In particular, the ubiquitous presence of indole rings in pharmaceuticals, agrochemicals, and functional materials are testament to the ever increasing interest in the design of mild and efficient synthetic routes to functionalized indole derivatives. This Review emphasizes the achievements in the selective catalytic functionalization of indoles (C? C bond‐forming processes) over the last four years.     

Asymptotic random graph intuition for the biased connectivity game

We study biased Maker/Breaker games on the edges of the complete graph, as introduced by Chvátal and Erd?s. We show that Maker, occupying one edge in each of his turns, can build a spanning tree, even if Breaker occupies b ≤ (1 ? o(1)) · edges in each turn. This improves a result of Beck, and is asymptotically best possible as witnessed by the Breaker‐strategy of Chvátal and Erd?s. We also give a strategy for Maker to occupy a graph with minimum degree c (where c = c(n) is a slowly growing function of n) while playing against a Breaker who takes b ≤ (1 ? o(1)) · edges in each turn. This result improves earlier bounds by Krivelevich and Szabó. Both of our results support the surprising random graph intuition: the threshold bias is asymptotically the same for the game played by two “clever” players and the game played by two “random” players. © 2009 Wiley Periodicals, Inc. Random Struct. Alg., 2009     

Electrokinetic migration across artificial liquid membranes Tuning the membrane chemistry to different types of drug substances

Twenty different basic drugs were electrokinetically extracted across a thin artificial organic liquid membrane with a 300 V d.c. electrical potential difference as the driving force. From a 300 microl aqueous sample (acidified corresponding to 10mM HCl), the drugs were extracted for 5 min through a 200 microm artificial liquid membrane of a water immiscible organic solvent immobilized in the pores of a polypropylene hollow fiber, and into a 30 microl aqueous acceptor solution of 10mM HCl inside the lumen of the hollow fiber. Hydrophobic basic drugs (logP>1.7) were effectively isolated utilizing 2-nitrophenyl octyl ether (NPOE) as the artificial liquid membrane, with recoveries up to 83%. For more hydrophilic basic drugs (logP<1.0), a mixture of NPOE and 25% (w/w) di-(2-ethylhexyl) phosphate (DEHP) was required to ensure efficient extraction, resulting in recoveries up to 75%. DEHP was expected to act as an ion-pair reagent ion-pairing the protonated hydrophilic drugs at the interface between the sample and the membrane, resulting in permeation of the interface.     

Efficient photoinduced DNA damage by coralyne

The photoinduced DNA damage by the berberine derivative coralyne is presented. The irradiation of coralyne in the presence of plasmid DNA namely, pBR322, leads to remarkably fast DNA damage by single-strand cleavage, as determined by agarose-gel electrophoresis. Even upon exposure to sunlight, almost all of the supercoiled plasmid is converted to the open circular form in less than a minute [c(pBR322) = 3.5 x 10(-9) M; c(coralyne) = 4.3 x 10(-5) M]. The efficiency of the DNA strand cleavage is not decreased in the presence of radical-trapping reagents such as tert-butanol or DMSO. Moreover, the extent of the DNA damage is the same under aerobic conditions and at reduced oxygen concentration. Thus, the formation of reactive intermediates such as hydroxyl radicals or singlet oxygen is excluded. These results show that the exposure of coralyne and derivatives thereof to light, even with moderate light intensity, needs to be avoided during experiments in which their biological activity is assessed by plasmid unwinding assays.