抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Surface plasmons are waves that propagate along the surface of a conductor. By altering the structure of a metal's surface, the properties of surface plasmons--in particular their interaction with light--can be tailored, which offers the potential for developing new types of photonic device. This could lead to miniaturized photonic circuits with length scales that are much smaller than those currently achieved. Surface plasmons are being explored for their potential in subwavelength optics, data storage, light generation, microscopy and bio-photonics.

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Surface plasmon subwavelength optics

We present experimental scattering data at microwave frequencies on a structured metamaterial that exhibits a frequency band where the effective index of refraction (n) is negative. The material consists of a two-dimensional array of repeated unit cells of copper strips and split ring resonators on interlocking strips of standard circuit board material. By measuring the scattering angle of the transmitted beam through a prism fabricated from this material, we determine the effective n, appropriate to Snell's law. These experiments directly confirm the predictions of Maxwell's equations that n is given by the negative square root of epsilon.mu for the frequencies where both the permittivity (epsilon) and the permeability (mu) are negative. Configurations of geometrical optical designs are now possible that could not be realized by positive index materials.

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Experimental Verification of a Negative Index of Refraction

We show that microstructures built from nonmagnetic conducting sheets exhibit an effective magnetic permeability /spl mu//sub eff/, which can be tuned to values not accessible in naturally occurring materials, including large imaginary components of /spl mu//sub eff/. The microstructure is on a scale much less than the wavelength of radiation, is not resolved by incident microwaves, and uses a very low density of metal so that structures can be extremely lightweight. Most of the structures are resonant due to internal capacitance and inductance, and resonant enhancement combined with compression of electrical energy into a very small volume greatly enhances the energy density at critical locations in the structure, easily by factors of a million and possibly by much more. Weakly nonlinear materials placed at these critical locations will show greatly enhanced effects raising the possibility of manufacturing active structures whose properties can be switched at will between many states.

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Magnetism from conductors and enhanced nonlinear phenomena

The emerging field of plasmonics has yielded methods for guiding and localizing light at the nanoscale, well below the scale of the wavelength of light in free space. Now plasmonics researchers are turning their attention to photovoltaics, where design approaches based on plasmonics can be used to improve absorption in photovoltaic devices, permitting a considerable reduction in the physical thickness of solar photovoltaic absorber layers, and yielding new options for solar-cell design. In this review, we survey recent advances at the intersection of plasmonics and photovoltaics and offer an outlook on the future of solar cells based on these principles.

Plasmonics for improved photovoltaic devices

In advanced field theories, there can be more than four dimensions to space, the excess dimensions described as compacted and unobservable on everyday length scales. We report a simple model, unconnected to field theory, for a compacted dimension realized in a metallic metasurface periodically structured in the form of a grating comprising a series of singularities. An extra dimension of the grating is hidden, and the surface plasmon excitations, though localized at the surface, are characterized by three wave vectors rather than the two of typical two-dimensional metal grating. We propose an experimental realization in a doped graphene layer.

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Compacted dimensions and singular plasmonic surfaces

1. Arrangement of the Catalogue.- 2. Standard Abbreviations.- 3. Superlattices and Matrix Notation.- Alphabetic Index of Common Names.- Alphabetic Index of Author's Names.- The Tables.- The Figures.

Surface Crystallographic Information Service : A Handbook of Surface Structures

This work was supported by the Leverhulme Trust, the Engineering and Physical Sciences Research Council (EPSRC), and the European Research Council (Contract No. 290981 PLASMONANOQUANTA)

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Transformation-optics insight into nonlocal effects in separated nanowires

The second paper in this series casts the Boudreaux-Heine method of calculating low-energy electron diffraction (LEED) intensities into a matrix form suitable for extension to complicated surface structures. Calculations are made for the 00 and 01, macron beams reflected from a nickel 111 surface, for norrmal incidence, using the potential described in paper I. Predicted peak positions agree with experiment within ±2 ev and relative intensities agree qualitatively. We interpret our results in terms of band structure. A second calculation for the same face of a nickel crystal with the surface layer displaced by 5% of the bulk spacing between layers is presented, the results of which are interpreted in terms of the large ratio between forward and backward scattering cross section of atoms.

The application of pseudopotentials to low-energy electron diffraction II: Calculation of the reflected intensities

With increasing interest in nanotechnology, the question arises of how heat is exchanged between materials separated by only a few nanometers of vacuum. Here, we present calculations of the contribution of phonons to heat transfer mediated by van der Waals forces and compare the results to other mechanisms such as coupling through near field fluctuations. Our results show a more dramatic decay with separation than previous work.

John B. Pendry

Papers

Compacted dimensions and singular plasmonic surfaces

Surface Crystallographic Information Service : A Handbook of Surface Structures

Transformation-optics insight into nonlocal effects in separated nanowires

The application of pseudopotentials to low-energy electron diffraction II: Calculation of the reflected intensities

Phonon-assisted heat transfer between vacuum-separated surfaces