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

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

Using the freedom of design that metamaterials provide, we show how electromagnetic fields can be redirected at will and propose a design strategy. The conserved fields-electric displacement field D, magnetic induction field B, and Poynting vector B-are all displaced in a consistent manner. A simple illustration is given of the cloaking of a proscribed volume of space to exclude completely all electromagnetic fields. Our work has relevance to exotic lens design and to the cloaking of objects from electromagnetic fields.

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Controlling Electromagnetic Fields

Fundamentals of Plasmonics.- Electromagnetics of Metals.- Surface Plasmon Polaritons at Metal / Insulator Interfaces.- Excitation of Surface Plasmon Polaritons at Planar Interfaces.- Imaging Surface Plasmon Polariton Propagation.- Localized Surface Plasmons.- Electromagnetic Surface Modes at Low Frequencies.- Applications.- Plasmon Waveguides.- Transmission of Radiation Through Apertures and Films.- Enhancement of Emissive Processes and Nonlinearities.- Spectroscopy and Sensing.- Metamaterials and Imaging with Surface Plasmon Polaritons.- Concluding Remarks.

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Plasmonics: Fundamentals and Applications

We present the design for an absorbing metamaterial (MM) with near unity absorbance A(omega). Our structure consists of two MM resonators that couple separately to electric and magnetic fields so as to absorb all incident radiation within a single unit cell layer. We fabricate, characterize, and analyze a MM absorber with a slightly lower predicted A(omega) of 96%. Unlike conventional absorbers, our MM consists solely of metallic elements. The substrate can therefore be optimized for other parameters of interest. We experimentally demonstrate a peak A(omega) greater than 88% at 11.5 GHz.

Perfect metamaterial absorber.

Disclosed herein are electrochemical fabrication platforms for making structures, arrays of structures and functional devices having selected nanosized and/or microsized physical dimensions, shapes and spatial orientations. Methods, systems and system components use an electrochemical stamping tool such as solid state polymeric electrolytes for generating patterns of relief and/or recessed features exhibiting excellent reproducibility, pattern fidelity and resolution on surfaces of solid state ionic conductors and in metal. Electrochemical stamping tools are capable high throughput patterning of large substrate areas, are compatible with commercially attractive manufacturing pathways to access a range of functional systems and devices including nano- and micro-electromechanical systems, sensors, energy storage devices, metal masks for printing, interconnects, and integrated electronic circuits.

Direct nanoscale patterning of surfaces by electrochemical imprinting

National Natural Science Foundation (China) (Grants 11204205, 60976018, 61274056 and 60990320)

Optical Curtain Effect: Extraordinary Optical Transmission Enhanced by Antireflection

Addendum: Multiscale metallic metamaterials Xiaoyu Zheng, William Smith, Julie Jackson, Bryan Moran, Huachen Cui, Da Chen, Jianchao Ye, Nicholas Fang, Nicholas Rodriguez, Todd Weisgraber and Christopher M. Spadaccini Nature Materials 15, 1100–1106 (2016); published online 18 July 2016; corrected after print 7 March 2017. In the version of this Article originally published, Fig. 3e used data from ref. 3 that has since been corrected. The Al2O3 nanolattice dataset has been corrected to reflect this. In addition, the Al2O3 hollowtube dataset from ref. 14 has been added to the plot. These changes do not affect the data or findings of the present study. The new figure is shown below.

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Addendum: Multiscale metallic metamaterials

Spin—an intrinsic angular momentum carried by elementary particles—has long been thought to be exclusive to quantum mechanical systems. The spin of photons, for example, is associated with the vectorial nature of electromagnetic waves [1]. In classical systems, however, the concept of a spinning degree of freedom is not as well defined. For instance, sound is often considered to be spinless due to the longitudinal and scalar-pressure field description of acoustic waves. It comes down to the question of whether the scalar theoretical framework is a complete description of acoustics in some scenarios. Fundamentally speaking, vector field theory is required for the accurate depiction of hydrodynamics, and some information about the degree of freedom of microscopic fluid motion might be lost when using the scalar-pressure acoustic equations. Indeed, most of the time, the vector potential in Stokes flows is regarded as an arbitrary quantity that does not participate in the sound emission and momentum transfer. Recently, researchers from theUniversity ofCalifornia, Berkeley and Tongji University observed the spinning motion of fluids in sound propagation for the first time [2], with brand new physical insights of such vector potentials. They also observed acoustic-spininduced torque due to the absorption of spin angular momentum on an acoustic probe, as well as spin-momentum locking. Scientists have long been seeking to establish a connection between quantum mechanical wave functions and fluid dynamics. For example, a set of well-established Madelung equations that illustrate the link between spin and orbital angular momentums [3] can be obtained via the decomposition of local velocity into two parts, as shown in Fig. 1: homogeneous component representing the velocity of the center ofmass, plus the inhomogeneous and microscopic contribution, which is the velocity of motion in the center-of-mass frame (some named it the internal ‘spin motion’ or Zitterbewegung, ‘trembling motion’ in German). Furthermore, it has been demonstrated that the concept of Bohm quantum potential in the Madelung fluid model is an equivalent way of showing the existence of spin and Zitterbewegung of particles, thus providing a physical interpretation

Echoes of fluid spin.

In this work, we present a systematic study of the plasmon modes in a system of vertically stacked pair of graphene discs. Quasistatic approximation is used to model the eigenmodes of the system. Eigen-response theory is employed to explain the spatial dependence of the coupling between the plasmon modes and a quantum emitter. These results show a good match between the semi-analytical calculation and full-wave simulations. Secondly, we have shown that it is possible to engineer the decay rates of a quantum emitter placed inside and near this cavity, using Fermi level tuning, via gate voltages and variation of emitter location and polarization. We highlighted that by coupling to the bright plasmon mode, the radiative efficiency of the emitter can be enhanced compared to the single graphene disc case, whereas the dark plasmon mode suppresses the radiative efficiency.

Nicholas X. Fang

Papers

Direct nanoscale patterning of surfaces by electrochemical imprinting

Optical Curtain Effect: Extraordinary Optical Transmission Enhanced by Antireflection

Addendum: Multiscale metallic metamaterials

Echoes of fluid spin.

Photon Emission Rate Engineering using Graphene Nanodisc Cavities