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 report on the transverse mode and polarization characteristics of a novel 1.52-/spl mu/m vertical-cavity laser that utilizes an InGaAsP strain-compensated quantum-well active layer and two AlAs/GaAs quarter-wave mirrors. The 6 and 8 /spl mu/m diameter devices exhibit room-temperature pulsed threshold currents as low as 4 mA, and a maximum output power of 14 mW was measured on a 60 /spl mu/m diameter device.

Transverse-mode and polarization characteristics of double-fused 1.52-/spl mu/m vertical-cavity lasers

We present a new method of inference applicable to robots and other intelligent machines. Inferences drawn by intelligent machines are based on measurements gathered through sensory perception. We demonstrate that the methods for managing uncertainty of meaning, which recently have been extended to a wide variety of non-human systems, generally yield qualitatively incorrect results when applied to the uncertainty of evidence available to an intelligent machine. We show that even in very simple machines, no amount of sophistication in the mathematical algorithms can compensate for incorrect assumptions about the physical model. Conversely, we also demonstrate that once the essential structure of the physical model is correctly described, classical probability theory yields simple algorithms for the evaluation of the degree of evidence as it propagates through complex inference networks, including diagnostic trees and multicausal nets. As a first application, we have derived the probability algorithms relevant to diagnosing the malfunctioning of a thermal evaporator. For this system, an inference network has been constructed and compared to an implementation based on a MYCIN-type expert system. The laboratory implementation of the system is also described.

Inference in intelligent machines: Application to a thermal evaporator

The photoluminescence and spin properties of ensembles of color centers in silicon carbide are enhanced by fabricating optically isolated slab waveguide structures and carefully controlling annealing and cooling conditions. We find that the photoluminescence signal of an ensemble of implanted defects is enhanced in slab waveguides by an order of magnitude over identically implanted bulk defects. The slab waveguide-enhanced photoluminescence of several defect species is used to study recombination and diffusion in the presence of thermal annealing with both rapid quench cooling and a longer return to ambient conditions. The confined mechanical geometry of a thin film is exploited to measure the spin-strain coupling of the negatively charged silicon monovacancy. The methods in this work can be used to exercise greater control on near-surface emitters in silicon carbide and better understand and control the effects of strain on spin measurements of silicon carbide based color centers.

https://aip.scitation.org/doi/pdf/10.1063/5.0087805

Optical and strain stabilization of point defects in silicon carbide

We report record high temperature performance of long wavelength vertical cavity lasers, operating continuous-wave up to 71/spl deg/C A record high long wavelength characteristic temperature (T/sub o/) of 132 K has been measured over an operating range of -75/spl deg/C to 35/spl deg/C

Double-fused 1.5 /spl mu/m vertical cavity lasers operating continuous wave up to 71/spl deg/C

There is increasing interest in using biostructures as templates to construct nanoscale-architectures. Many biosystems can self-assemble into regular structures of less than 100 nm and contain functional groups that bind to inorganic particles. In this study, fabrication of microtubule (MT)-based Au nanowires is investigated. Microtubules are fibrous proteins that are rigid hollow tubes about 25 nm in outer diameter and microns in length. We deposit nanoparticles of Au on microtubules by a new method involving photochemical reduction, in which MTs are mixed with Au3+ and the surfactant poly(oxyethelene) isooctylphenyl ether (Triton X-100 or TX-100). Exposure of the solution to UV irradiation reduces Au3+ to Au0. By varying the Au3+ and TX-100 concentration in the solution, Au particle size can be well controlled and uniform Au coverage on microtubules is observed. Multiple UV exposure steps induce Au particle growth and leads to dense coverage of Au on the MT.

Evelyn L. Hu

Papers

Transverse-mode and polarization characteristics of double-fused 1.52-/spl mu/m vertical-cavity lasers

Inference in intelligent machines: Application to a thermal evaporator

Optical and strain stabilization of point defects in silicon carbide

Double-fused 1.5 /spl mu/m vertical cavity lasers operating continuous wave up to 71/spl deg/C

Nanoscale Assembly of Gold Nanowires Templated by Microtubules