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

In this Progress Report we provide an update on recent developments in inkjet printing technology and its applications, which include organic thin-film transistors, light-emitting diodes, solar cells, conductive structures, memory devices, sensors, and biological/pharmaceutical tasks. Various classes of materials and device types are in turn examined and an opinion is offered about the nature of the progress that has been achieved.

Inkjet Printing—Process and Its Applications

2.3. Medical Devices and Sensors 9 2.4. Radio Frequency Applications 10 3. Materials 12 3.1. Organic Electronics Materials 12 3.2. Semiconducting Polymer Design 13 3.3. Poly(3-alkylthiophenes) 14 3.4. Poly(thieno(3,2-b)thiophenes 15 3.5. Benchmark Polymer Semiconductors 15 3.6. High Performance Polymer Semiconductors 15 4. Device Stability 16 4.1. Bias Stress in Organic Transistors 17 4.1.1. Bias Stress Characterization 17 4.1.2. Bias Stress Mechanism 18 4.2. Short Channel Effects in Organic Transistors 19 5. Materials Patterning and Integration 20 6. Conclusions 22 7. Acknowledgments 22 8. References 22

Materials and applications for large area electronics: solution-based approaches.

Over the past 20 years, organic transistors have developed from a laboratory curiosity to a commercially viable technology. This critical review provides a short summary of several important aspects of organic transistors, including materials, microstructure, carrier transport, manufacturing, electrical properties, and performance limitations (200 references).

Organic thin-film transistors.

We demonstrate inkjet printing as a viable method for large-area fabrication of graphene devices. We produce a graphene-based ink by liquid phase exfoliation of graphite in N-methylpyrrolidone. We use it to print thin-film transistors, with mobilities up to ∼95 cm2 V–1 s–1, as well as transparent and conductive patterns, with ∼80% transmittance and ∼30 kΩ/□ sheet resistance. This paves the way to all-printed, flexible, and transparent graphene devices on arbitrary substrates.

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Inkjet-printed graphene electronics.

Thin-film transistor (TFT) backplanes fabricated by using jet printing as the only patterning method are reported. Additive and subtractive printing processes are combined to make 128×128 pixel active matrix arrays with 340μm pixel size. The semiconductor used, a regioregular polythiophene, poly[5,5′-bis(3-dodecyl-2-thienyl)-2,2′-bithiophene]; (PQT-12) is deposited by inkjet printing and exhibits average TFT mobility of 0.06cm2∕Vs, on/off ratios of 106, and minimal bias stress. The printed TFTs have high yield with a narrow performance distribution. The pixel design benefits from the registration accuracy of jet printing and it is shown that the electrical performance is suitable for addressing capacitive media displays.

All jet-printed polymer thin-film transistor active-matrix backplanes

Disordered silicon nanowire mats have high diffuse optical reflectivity, in striking contrast to the low reflectivity of orientationally ordered nanowires The reflectivity decreases with increasing photon energy across the visible and near infrared spectrum due to absorption in the nanowires A simple model is used to estimate that the incident photon interacts with up to 20 nanowires before being reflected A thin coating of hydrogenated amorphous silicon enhances the nanowire absorption

Reflectivity of disordered silicon nanowires

A low temperature process for dehydrogenating amorphous silicon using lasers Dehydrogenation occurs by irradiating one or more areas of a hydrogenated amorphous silicon layer with laser beam pulses at a relatively low energy density After the multiple laser pulse irradiation at a relatively low energy density, the laser energy density is increased and multiple irradiation at a higher energy density is performed If after the multiple irradiation at the higher energy density the amorphous silicon hydrogen content is still too high, dehydrogenation proceeds by multiple irradiations at a yet higher energy density The irradiation at the various energy densities can result in the formation of polysilicon due to melting of the amorphous silicon layer As irradiation may be selectively applied to the amorphous silicon, an integral amorphous silicon-polysilicon structure may be formed

Low temperature process for laser dehydrogenation and crystallization of amorphous silicon

Selective dehydrogenation and crystallization are realized by a three‐step incremental increase in laser energy density X‐ray diffraction and transmission electron microscopy show that the polycrystalline grains formed with this three‐step process are similar to those after a conventional one‐step laser crystallization of unhydrogenated amorphous silicon The grain size increases with increasing laser energy density up to a peak value of a few micrometers The grain size decreases with further increases in laser energy density The transistor field effect mobility is correlated to the material properties, increasing gradually with laser energy density until reaching its maximum value Thereafter, the transistors suffer from leakage through the gate insulators A dual dielectric gate insulator has been developed for these bottom‐gate thin film transistors Our structure simplifies fabrication of both high quality amorphous and polycrystalline thin film transistors on the same glass substrate We discuss t

Grain growth in laser dehydrogenated and crystallized polycrystalline silicon for thin film transistors

Two dimensional amorphous silicon arrays are the emerging technology for digital medical X-ray imaging. This paper demonstrates an improved pixel design compared with the current generation of imagers. The geometry of the pixel sensor has been extended from a mesa isolated structure into a continuous layer above the readout structures of the array. This approach improves sensitivity to visible light, and to X-ray illumination when coupled with a conversion phosphor. Furthermore, this 3-dimensional geometry allows for the fabrication of the finest pitch amorphous silicon array yet manufactured, with a pixel size of 64 /spl mu/m square. A test array (512/spl times/640 pixels) has been fabricated and tested which demonstrates the success of this approach.

Rene A. Lujan

Papers

All jet-printed polymer thin-film transistor active-matrix backplanes

Reflectivity of disordered silicon nanowires

Low temperature process for laser dehydrogenation and crystallization of amorphous silicon

Grain growth in laser dehydrogenated and crystallized polycrystalline silicon for thin film transistors

High resolution X-ray imaging using amorphous silicon flat-panel arrays