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.

/pdf/surface-plasmon-subwavelength-optics-5e55p12p4o.pdf

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.

/pdf/experimental-verification-of-a-negative-index-of-refraction-37hlxn3tta.pdf

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.

/pdf/magnetism-from-conductors-and-enhanced-nonlinear-phenomena-2fpnoamwae.pdf

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

We show that complex periodic metasurfaces can be simply represented by conformal transformations from the flat surface of a slab of material to a periodic grating leading to a methodology for computing their properties. Matrix equations are solved to give accurate solutions of Maxwell's equations with detailed derivations given in the Supplemental Material.

/pdf/computing-one-dimensional-metasurfaces-2r11xlx22i.pdf

Computing one-dimensional metasurfaces

The absorption of elastic flux for electrons with energies in the range 0-20 Hartrees (0-500 eV), interacting with tightly bound bands in a crystal. The inelastic scattering is usually dominated by conduction and valence bands and varies with energy in a manner substantially independent of the band being excited, asymptotically as E-12/lnE. In close-packed structures the strength of absorption varies only weakly over the unit cell, but for more open structures large variations can be expected from one part of the cell to another. The results are relevant to LEED and photoemission experiments.

http://iopscience.iop.org/article/10.1088/0022-3719/8/8/011/pdf

Inelastic scattering of low-energy electrons by tight-binding electrons

The expansion of Tensor-LEED in Cartesian coordinates

The transmission of waves through disordered media has received much attention in the context of electrical conduction, and numerous techniques have been brought to bear on the problem. Here the authors focus on the reflection coefficient, a closely related quantity. The change in reflectivity on adding a new element to a disordered chain can be calculated by a recursion formula. This in turn suggests a novel formulation of the problem in terms of transfer matrices. These new matrices can be calculated explicitly and, although in principle of infinite dimensions, can be approximated by a truncated form. Using this tool they show how some problems can be solved exactly and how an accurate perturbation expansion can be made for others.

Reflection of waves from disordered surfaces

/pdf/controlling-light-on-the-nanoscale-invited-review-1e3rtioa4b.pdf

John B. Pendry

Papers

Computing one-dimensional metasurfaces

Inelastic scattering of low-energy electrons by tight-binding electrons

The expansion of Tensor-LEED in Cartesian coordinates

Reflection of waves from disordered surfaces

Controlling Light on the Nanoscale (Invited Review)