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

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.

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Spintronics: Fundamentals and applications

We present a comprehensive, up-to-date compilation of band parameters for the technologically important III–V zinc blende and wurtzite compound semiconductors: GaAs, GaSb, GaP, GaN, AlAs, AlSb, AlP, AlN, InAs, InSb, InP, and InN, along with their ternary and quaternary alloys. Based on a review of the existing literature, complete and consistent parameter sets are given for all materials. Emphasizing the quantities required for band structure calculations, we tabulate the direct and indirect energy gaps, spin-orbit, and crystal-field splittings, alloy bowing parameters, effective masses for electrons, heavy, light, and split-off holes, Luttinger parameters, interband momentum matrix elements, and deformation potentials, including temperature and alloy-composition dependences where available. Heterostructure band offsets are also given, on an absolute scale that allows any material to be aligned relative to any other.

Band parameters for III–V compound semiconductors and their alloys

Thermoelectric materials are of interest for applications as heat pumps and power generators. The performance of thermoelectric devices is quantified by a figure of merit, ZT, where Z is a measure of a material's thermoelectric properties and T is the absolute temperature. A material with a figure of merit of around unity was first reported over four decades ago, but since then-despite investigation of various approaches-there has been only modest progress in finding materials with enhanced ZT values at room temperature. Here we report thin-film thermoelectric materials that demonstrate a significant enhancement in ZT at 300 K, compared to state-of-the-art bulk Bi2Te3 alloys. This amounts to a maximum observed factor of approximately 2.4 for our p-type Bi2Te3/Sb2Te3 superlattice devices. The enhancement is achieved by controlling the transport of phonons and electrons in the superlattices. Preliminary devices exhibit significant cooling (32 K at around room temperature) and the potential to pump a heat flux of up to 700 W cm-2; the localized cooling and heating occurs some 23,000 times faster than in bulk devices. We anticipate that the combination of performance, power density and speed achieved in these materials will lead to diverse technological applications: for example, in thermochemistry-on-a-chip, DNA microarrays, fibre-optic switches and microelectrothermal systems.

Thin-film thermoelectric devices with high room-temperature figures of merit

In 1974 an article appeared in Science magazine with the dry-sounding title “Judgment Under Uncertainty: Heuristics and Biases” by a pair of psychologists who were not well known outside their discipline of decision theory. In it Amos Tversky and Daniel Kahneman introduced the world to Prospect Theory, which mapped out how humans actually behave when faced with decisions about gains and losses, in contrast to how economists assumed that people behave. Prospect Theory turned Economics on its head by demonstrating through a series of ingenious experiments that people are much more concerned with losses than they are with gains, and that framing a choice from one perspective or the other will result in decisions that are exactly the opposite of each other, even if the outcomes are monetarily the same. Prospect Theory led cognitive psychology in a new direction that began to uncover other human biases in thinking that are probably not learned but are part of our brain’s wiring.

Thinking fast and slow.

A brief review of high frequency phonon transport experiments indielectric solids is presented. A major emphasis of this paper is on recenttime of flight experiments on the generation and propagation of near zone-edgetransverse acoustic phonon pulses in III-V semiconductors such as GaAs. Thetheoretical status of lifetimes of high frequency phonons is also discussed.

Transport of high energy phonons

In the study of innovation institutions, it is important to consider how different institutional models can affect a research organization in conducting or funding successful work. As an industry collaborative, Semiconductor Research Corporation (SRC) provides an example of a privately funded institution that leverages the inputs of several member companies, along with federal funding, to accomplish innovation in its mission area. SRC has several component programs, all attempting to find innovative solutions to semiconductor problems, but on different time scales, and in different technology areas. But how does SRC use its resources to ensure these goals? Through data gathered from semi-structured qualitative interviews and SRC documentation, this paper addresses that question. SRC has found a way to leverage industry money to motivate and develop a robust field of university research for over 30 years. SRC uses several mechanisms for maintaining an application focused, member-centered decision process, institutional flexibility, and strong ties between industry contributors and university researchers. SRC has continued to keep its members satisfied by training thousands of graduate students for employment in their member companies, by focusing on precompetitive research that addresses industry requirements, and doing so in a manner that operates leanly, with low overhead to its funders. Given these successes, we identify aspects of SRC operations, such as a focus on its member company needs, frequent interactions between funders and researchers, flexible funding mechanisms, and focus on workforce development, that may be diffusible to innovation institutions, including federal research efforts.

Semiconductor Research Corporation: A Case Study in Cooperative Innovation Partnerships

Introduction Private sector firms are critical players in energy technology innovation. As described below, the private sector funds and carries out the majority of energy research, development, and demonstration (RD&D) in the United States. New energy technologies can make significant contributions to major energy challenges only if they are adopted on a broad scale by the private sector. In this chapter, therefore, we explore two sets of questions. First, what kinds of energy innovation are taking place in the private sector in the United States today, and how can the federal government best encourage them to do more? Second, how can U.S. government energy RD&D partnerships with the private sector – a major part of the federal investment in energy RD&D – be made more effective? As we show in this chapter, improving the U.S. Department of Energy (DOE)'s work with the private sector is important not only because the private sector will ultimately take technologies into the market, but because collaborative work between DOE and others makes up about 30% of the energy RD&D budget and 55% of the Science budget through grants and collaborative agreements. Within energy RD&D especially, for-profit firms receive 60% of all funding for collaborative work, and firms contribute more than they receive to jointly funded projects, so that firms represent 65% of the total collaborative effort.

Transforming U.S. Energy Innovation: Encouraging Private Sector Energy Technology Innovation and Public–Private Cooperation

Science, technology, engineering and mathematics (STEM) policies in the Gulf Arab States are as diverse as the individual economies and political processes that characterize its member states. During the past decade, a number of expert review groups have argued that science and technology policy needs to be reformed and revitalized in the Gulf Arab States. Several reports and studies have identified the need to develop and adopt more rigorous plans to raise the level of research and development (RD 2) how effective are the science policies enacted by regional governments in the Gulf, and how can these policies be enhanced; 3) what role do regional or international collaborations play in a research and training network system, and how can these regional partnerships be bolstered; and, 4) how can the international community assist to accelerate progress and reduce the science knowledge gap. Our results show that the under-performance of the Gulf region in science and technology appears to be due to a: 1) lack of early exposure of young adults to science, 2) low perception of the societal value of science, 3) lack of institutional (e.g. university) resources, 4) too few scientists who make science their long-term careers, 5) lack of an integrated, international research network of collaboration, and 6) lack of motivation among students.  We also report on our findings regarding the state-of-the-art of the research enterprise, and the strengths and weaknesses of the research and training environment as perceived by educators/administrators in the region.

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Venkatesh Narayanamurti

Papers

Transport of high energy phonons

Semiconductor Research Corporation: A Case Study in Cooperative Innovation Partnerships

Transforming U.S. Energy Innovation: Encouraging Private Sector Energy Technology Innovation and Public–Private Cooperation

Prospects for Policy Advances in Science and Technology in the Gulf Arab States: The Role for International Partnerships

Single particle and collective response in the magnetophotoresistance of a high mobility 2DES under microwave excitation