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

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/adom.201700501

Chirality and Nanophotonics

Poisoning of the methanation reaction on the Ni(100) surface; theoretical calculations compared with the results of goodman et al

Electromagnetic waves in a system with a space- and time-dependent boundary experience both diffraction and Doppler-like frequency conversion In order to analyze such situations, conventional methods call for either the eigenmodes or the dyadic Green's function in space- and time-dependent media Here, we propose a dynamical differential method which does not require either of them Our method utilizes a dynamical coordinate transformation in order to simplify the calculation of the optical response of the space- and time-dependent system We reveal that the diffraction symmetry is broken in the presence of traveling-wave-type spatiotemporal modulation

Calculating spatiotemporally modulated surfaces: A dynamical differential formalism

Multi-atom correlations in X-ray absorption near-edge structure

Exemplary embodiments enable an enhanced direct-viewing optical device to include customized adjustments that accommodate various optical aberrations of a current user. Customized optical elements associated with an authorized current user are incorporated with the direct-viewing optical device to produce a specified change in optical wavefront at an exit pupil. Possible replacement optical elements may have refractive and/or reflective and/or diffractive and/or transmissive characteristics based on current performance viewing factors for a given field of view of the direct-viewing optical device. Some embodiments enable dynamic repositioning and/or transformation of replaceable corrective optical elements responsive to a detected shift of a tracked gaze direction of a current user. Replaceable interchangeable corrective optical elements may be fabricated for current usage or retained in inventory for possible future usage in designated direct-viewing optical devices.

John B. Pendry

Papers

Chirality and Nanophotonics

Poisoning of the methanation reaction on the Ni(100) surface; theoretical calculations compared with the results of goodman et al

Calculating spatiotemporally modulated surfaces: A dynamical differential formalism

Multi-atom correlations in X-ray absorption near-edge structure

Optical device with interchangeable corrective elements