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

Titanium Dioxide Nanomaterials: Synthesis, Properties, Modifications, and Applications

Despite the concern that has been expressed about potential method biases, and the pervasiveness of research settings with the potential to produce them, there is disagreement about whether they really are a problem for researchers in the behavioral sciences. Therefore, the purpose of this review is to explore the current state of knowledge about method biases. First, we explore the meaning of the terms “method” and “method bias” and then we examine whether method biases influence all measures equally. Next, we review the evidence of the effects that method biases have on individual measures and on the covariation between different constructs. Following this, we evaluate the procedural and statistical remedies that have been used to control method biases and provide recommendations for minimizing method bias.

Sources of Method Bias in Social Science Research and Recommendations on How to Control It

Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency. DSC research groups have been established around the worl ...

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Dye-Sensitized Solar Cells

Cell signaling by receptor-tyrosine kinases

CONJUGATED polymers are organic semiconductors, the semiconducting behaviour being associated with the π molecular orbitals delocalized along the polymer chain. Their main advantage over non-polymeric organic semiconductors is the possibility of processing the polymer to form useful and robust structures. The response of the system to electronic excitation is nonlinear—the injection of an electron and a hole on the conjugated chain can lead to a self-localized excited state which can then decay radiatively, suggesting the possibility of using these materials in electroluminescent devices. We demonstrate here that poly(p-phenylene vinylene), prepared by way of a solution-processable precursor, can be used as the active element in a large-area light-emitting diode. The combination of good structural properties of this polymer, its ease of fabrication, and light emission in the green–yellow part of the spectrum with reasonably high efficiency, suggest that the polymer can be used for the development of large-area light-emitting displays.

Light-emitting diodes based on conjugated polymers

A new exciting interdisciplinary research field has evolved following the discovery that conjugated polymers can emit light when put into light-emitting diodes. A myriad of light-emitting polymers (examples of which are shown below) shining in various colors have been developed through chemical intuition and structural design.

Electroluminescent conjugated polymers : seeing polymers in a new light

Characterization of a 3-phosphoinositide-dependent protein kinase which phosphorylates and activates protein kinase Bα

A review was presented to demonstrate a historical description of the synthesis of light-emitting conjugated polymers for applications in electroluminescent devices. Electroluminescence (EL) was first reported in poly(para-phenylene vinylene) (PPV) in 1990 and researchers continued to make significant efforts to develop conjugated materials as the active units in light-emitting devices (LED) to be used in display applications. Conjugated oligomers were used as luminescent materials and as models for conjugated polymers in the review. Oligomers were used to demonstrate a structure and property relationship to determine a key polymer property or to demonstrate a technique that was to be applied to polymers. The review focused on demonstrating the way polymer structures were made and the way their properties were controlled by intelligent and rational and synthetic design.

Synthesis of Light-Emitting Conjugated Polymers for Applications in Electroluminescent Devices

CONJUGATED polymers have been incorporated as active materials into several kinds of electronic device, such as diodes, transistors1 and light-emitting diodes2. The first polymer light-emitting diodes were based on poly(p-phenylene vinylene) (PPV), which is robust and has a readily processible precursor polymer. Electroluminescence in this material is achieved by injection of electrons into the conduction band and holes into the valence band, which capture one another with emission of visible radiation. Efficient injection of electrons has previously required the use of metal electrodes with low work functions, primarily calcium; but this reactive metal presents problems for device stability. Here we report the fabrication of electroluminescent devices using a new family of processible poly(cyanoterephthalylidene)s. As the lowest unoccupied orbitals of these polymers (from which the conduction band is formed) lie at lower energies than those of PPV, electrodes made from stable metals such as aluminium can be used for electron injection. For hole injection, we use indium tin oxide coated with a PPV layer; this helps to localize charge at the interface between the PPV and the new polymer, increasing the efficiency of recombination. In this way, we are able to achieve high internal efficiencies (photons emitted per electrons injected) of up to 4% in these devices.

Andrew B. Holmes

Papers

Light-emitting diodes based on conjugated polymers

Electroluminescent conjugated polymers : seeing polymers in a new light

Characterization of a 3-phosphoinositide-dependent protein kinase which phosphorylates and activates protein kinase Bα

Synthesis of Light-Emitting Conjugated Polymers for Applications in Electroluminescent Devices

Efficient light-emitting diodes based on polymers with high electron affinities