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

We have fabricated L3-type photonic crystal microcavities with embedded InAs/GaAs quantum dots as active material. Single mode lasing has been found for devices emitting between 910-975 nm showing ultra-low lasing thresholds down to 160 nanoWatt.

Photonic crystal quantum-dot laser with ultra-low threshold

In this paper, we use a 980 nm laser to optically pump 1.55 /spl mu/m vertical cavity surface emitting lasers (VCSELs) and demonstrate record output power of 2 mW at 25/spl deg/C and a record operating temperature of 105/spl deg/C with 140 /spl mu/W output power. Single mode operation with a side mode suppression ratio (SMSR) of 61 dB was achieved and transmission over 25 km of fiber at a bit rate of 6 Gb/s was demonstrated.

http://ieeexplore.ieee.org/iel5/68/17830/00823488.pdf

High temperature, optically pumped, 1.55 /spl mu/m VCSEL operating at 6 Gb/s

In this study, we use a quantum well (QW) probe structure to explore the size dependent effects of sidewall recombination in GaN. Mesas 0.8-7 μm in width with pitches of 4 μm, 8 μm, and 12 μm were etched into the QW probe structure, exposing the QW at the sidewalls. Several etch conditions were investigated. Room temperature photoluminescence (PL) measurements, using a He-Cd laser as an excitation source and laser spot size of approximately 230 μm, were taken before and after the mesas were etched. The effects of sidewall formation were quantified by comparing the maximum PL intensity of the QW before and after etch. Higher remaining PL intensity was observed for etch conditions which used both Ar ions and Cl 2 gas instead of only Ar ions. The fraction of remaining PL decreased with decreasing mesa width, however the remaining PL intensity was relatively large even for small features. The preliminary data suggested that GaN is relatively insensitive to sidewall damage.

Investigation of Sidewall Recombination in GaN Using a Quantum Well Probe

Summary form only given. Electrically injected long-wavelength vertical cavity lasers (VCLs) employing InGaAsP (1.3 mu m) active regions fused to GaAs-AlAs mirrors on GaAs substrates are demonstrated. The lasers operate pulsed at room temperature (300 K) with a threshold current of 9 mA and a threshold current density of 9.5 kA/cm/sup 2/. These devices operate CW (continuous wave) at temperatures as high as 230 K; the CW threshold current at 230 K is 3.6 mA. The use of the GaAs-AlAs mirror makes the device more mechanically robust, improving the thermal conductivity and reducing problems with nonuniform injection. >

Low threshold, electrically injected InGaAsP (1.3 /spl mu/m) vertical cavity lasers on GaAs substrates

Two-dimensional single-line defect Photonic Crystal (PC) waveguides were fabricated and characterized by optical transmission measurements. Different PC-waveguide tapers were investigated for coupling to access ridge waveguides; ~10-dB coupling efficiency enhancement was observed over un-tapered waveguides

Evelyn L. Hu

Papers

Photonic crystal quantum-dot laser with ultra-low threshold

High temperature, optically pumped, 1.55 /spl mu/m VCSEL operating at 6 Gb/s

Investigation of Sidewall Recombination in GaN Using a Quantum Well Probe

Low threshold, electrically injected InGaAsP (1.3 /spl mu/m) vertical cavity lasers on GaAs substrates

Transmission measurement of tapered single line defect photonic crystal waveguide