Lactose as a “Trojan Horse” for Quantum Dot Cell Transport

A series of glycan‐coated quantum dots were prepared to probe the effect of glycan presentation in intracellular localization in HeLa and SV40 epithelial cells. We show that glycan density mostly impacts on cell toxicity, whereas glycan type affects the cell uptake and intracellular localization. Moreover, we show that lactose can act as a “Trojan horse” on bi‐functionalized QDs to help intracellular delivery of other non‐internalizable glycan moieties and largely avoid the endosomal/lysosomal degradative pathway.     

Microwave transmission through a single subwavelength annular aperture in a metal plate

The resonant transmission of a small annular aperture, with a diameter much smaller than the radiation wavelength, in a thin metal plate is studied at microwave frequencies. It transpires that such an annular aperture supports several resonant guided modes, including those that are not quantized in the azimuthal direction. Such modes have resonant frequencies that are largely independent of the diameter of the annular aperture, thus being supported by annular apertures that tend to zero radius. The transmittance of such a structure at microwave frequencies is detailed and compared with the predictions of a finite element method model.     

Electronic state selectivity in dication-molecule single electron transfer reactions: NO(2+) + NO

The single-electron transfer reaction between NO(2+) and NO, which initially forms a pair of NO(+) ions, has been studied using a position-sensitive coincidence technique. The reactivity in this class of collision system, which involves the interaction of a dication with its neutral precursor, provides a sensitive test of recent ideas concerning electronic state selectivity in dicationic single-electron transfer reactions. In stark contrast to the recently observed single-electron transfer reactivity in the analogous CO(2)(2+)/CO(2) and O(2)(2+)/O(2) collision systems, electron transfer between NO(2+) and NO generates two product NO(+) ions which behave in an identical manner, whether the ions are formed from NO(2+) or NO. This observed behaviour is in excellent accord with the recently proposed rationalization of the state selectivity in dication-molecule SET reactions using simple propensity rules involving one-electron transitions.     

A Comparison of Two Variational Methods

A discussion is given of the relation between the maximum functionaltheorem and Schwinger's variational principle, and it is shownthat the bound given by Schwinger's principle is better thanor the same as that given by the maximum functional theorem.     

Waveguide arrays as plasmonic metamaterials: transmission below cutoff

Since the work of Ebbesen et al. [Nature (London) 391, 667 (1998)], there has been immense interest in the optical properties of subwavelength holes in metal layers. While the enhanced transmission observed is generally associated with surface plasmon polaritons (SPPs), theoretical predictions suggest a similar response with perfectly conducting materials. However, Pendry et al. [Science 305, 847 (2004)] proposed that, if textured on a subwavelength scale, even perfect conductors support surface modes. Here, using microwave radiation incident upon an array of metal waveguides, we observe peaks in the transmissivity below cutoff and confirm the crucial role of these SPP-like modes in the mechanism responsible.     

Further Gurtin-type Variational Principles for Linear Initial Value Problems

Following the variational principles for linear initial valueproblems associated with the wave and heat conduction equationsdiscussed by Gurtin and Leitmann and using time convolutionsit is shown that general variational principles exist for theseproblems with sources on the boundaries and within the regionunder consideration.