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

This review describes a new paradigm of electronics based on the spin degree of freedom of the electron. Either adding the spin degree of freedom to conventional charge-based electronic devices or using the spin alone has the potential advantages of nonvolatility, increased data processing speed, decreased electric power consumption, and increased integration densities compared with conventional semiconductor devices. To successfully incorporate spins into existing semiconductor technology, one has to resolve technical issues such as efficient injection, transport, control and manipulation, and detection of spin polarization as well as spin-polarized currents. Recent advances in new materials engineering hold the promise of realizing spintronic devices in the near future. We review the current state of the spin-based devices, efforts in new materials fabrication, issues in spin transport, and optical spin manipulation.

http://science.sciencemag.org/content/sci/294/5546/1488.full.pdf

Spintronics: a spin-based electronics vision for the future.

Spintronics, or spin electronics, involves the study of active control and manipulation of spin degrees of freedom in solid-state systems. This article reviews the current status of this subject, including both recent advances and well-established results. The primary focus is on the basic physical principles underlying the generation of carrier spin polarization, spin dynamics, and spin-polarized transport in semiconductors and metals. Spin transport differs from charge transport in that spin is a nonconserved quantity in solids due to spin-orbit and hyperfine coupling. The authors discuss in detail spin decoherence mechanisms in metals and semiconductors. Various theories of spin injection and spin-polarized transport are applied to hybrid structures relevant to spin-based devices and fundamental studies of materials properties. Experimental work is reviewed with the emphasis on projected applications, in which external electric and magnetic fields and illumination by light will be used to control spin and charge dynamics to create new functionalities not feasible or ineffective with conventional electronics.

/pdf/spintronics-fundamentals-and-applications-2dx38n6phu.pdf

Spintronics: Fundamentals and applications

We report a method to form multifunctional polymer coatings through simple dip-coating of objects in an aqueous solution of dopamine. Inspired by the composition of adhesive proteins in mussels, we used dopamine self-polymerization to form thin, surface-adherent polydopamine films onto a wide range of inorganic and organic materials, including noble metals, oxides, polymers, semiconductors, and ceramics. Secondary reactions can be used to create a variety of ad-layers, including self-assembled monolayers through deposition of long-chain molecular building blocks, metal films by electroless metallization, and bioinert and bioactive surfaces via grafting of macromolecules.

/pdf/mussel-inspired-surface-chemistry-for-multifunctional-1noq7vcby7.pdf

Mussel-Inspired Surface Chemistry for Multifunctional Coatings

Research on fluorescent semiconductor nanocrystals (also known as quantum dots or qdots) has evolved over the past two decades from electronic materials science to biological applications. We review current approaches to the synthesis, solubilization, and functionalization of qdots and their applications to cell and animal biology. Recent examples of their experimental use include the observation of diffusion of individual glycine receptors in living neurons and the identification of lymph nodes in live animals by near-infrared emission during surgery. The new generations of qdots have farreaching potential for the study of intracellular processes at the single-molecule level, high-resolution cellular imaging, long-term in vivo observation of cell trafficking, tumor targeting, and diagnostics.

/pdf/quantum-dots-for-live-cells-in-vivo-imaging-and-diagnostics-3y9ayecoh8.pdf

Quantum Dots for Live Cells, in Vivo Imaging, and Diagnostics

A light emitting device includes a substrate layer, a first injection contact positioned over the substrate layer, a first dielectric layer positioned over the first injection contact, a light emission layer positioned over the first dielectric layer, a second dielectric layer positioned over the light emission layer and a second injection contact positioned over the second dielectric layer. The light emission layer includes an organic template having binding sites for binding nanoparticles into an array. The wavelength of emitted light is dependent upon the size of the nanoparticles and the pitch of the array. The light emitting device may include a first plurality of binding sites for binding a first set of nanoparticles and a second plurality of binding sites for binding a second set of nanoparticles. The wavelength depends upon a ratio of the first plurality to the second plurality of binding sites.

Light emitting devices made by bio-fabrication

A practical technology for self‐aligned Si‐Zn diffusion into GaAs and AlGaAs has been developed. It is found that the use of a Si film alone for self‐aligned Si‐Zn diffusion is subject to serious problems of morphology degradation and doping contamination during the process of the Si diffusion. A procedure combining the use of a SiO2 film as an encapsulant with a sputtered Si film as source for Si diffusion and mask for Zn diffusion is investigated in detail. Optimum thicknesses of the Si and SiO2 films are determined to be 180 and 550 A, respectively.

Self‐aligned Si‐Zn diffusion into GaAs and AlGaAs

The etch rates of GaInAs and AlInAs were characterized using a mixture of methane, hydrogen, and argon as a function of self‐bias voltage. Effectively infinite etch selectivity between GaInAs and AlInAs was found for voltages below 200 V. This highly selective etch process was applied to the gate recess of a high electron mobility transistor device, and preliminary device measurements were made.

Highly selective reactive ion etch process for InP‐based device fabrication using methane/hydrogen/argon

We have studied the effects of hydrogenation on the luminescence efficiency of near‐surface strained InGaAs/GaAs and unstrained GaAs/AlGaAs quantum wells (QWs). By using two different materials with an analogous structure, we have been able to clarify the effects of substrate temperature, ion dosage, strain profile in the material, and material quality on the local hydrogen concentration. This in turn modifies the behavior of hydrogen, the formation of hydrogen‐related defects, and the variation of luminescence efficiency from the near‐surface QW.

Study of hydrogenation on near‐surface strained and unstrained quantum wells

The authors report on the dispersive phase response of light traversing a tapered optical fiber coupled to the whispering-gallery modes (WGMs) of GaAs microdisks with cavity Q factors of up to 3×105 at wavelengths of around 1.5μm. The group delay of the coupled light, that is, a derivative of the phase shift, becomes positive (+10ps) and then negative (−55ps) near the high-Q WGM resonances, as compared with a reference group delay without evanescent-wave coupling. The chromatic dispersion becomes as high as ±8ns∕nm near WGM wavelengths.

/pdf/dispersive-phase-response-in-optical-waveguide-resonator-vapwk6fmcz.pdf

Evelyn L. Hu

Papers

Light emitting devices made by bio-fabrication

Self‐aligned Si‐Zn diffusion into GaAs and AlGaAs

Highly selective reactive ion etch process for InP‐based device fabrication using methane/hydrogen/argon

Study of hydrogenation on near‐surface strained and unstrained quantum wells

Dispersive phase response in optical waveguide-resonator system