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

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Li-ion batteries have transformed portable electronics and will play a key role in the electrification of transport. However, the highest energy storage possible for Li-ion batteries is insufficient for the long-term needs of society, for example, extended-range electric vehicles. To go beyond the horizon of Li-ion batteries is a formidable challenge; there are few options. Here we consider two: Li-air (O(2)) and Li-S. The energy that can be stored in Li-air (based on aqueous or non-aqueous electrolytes) and Li-S cells is compared with Li-ion; the operation of the cells is discussed, as are the significant hurdles that will have to be overcome if such batteries are to succeed. Fundamental scientific advances in understanding the reactions occurring in the cells as well as new materials are key to overcoming these obstacles. The potential benefits of Li-air and Li-S justify the continued research effort that will be needed.

Li-O2 and Li-S batteries with high energy storage.

Microstructures and properties of high-entropy alloys

Energy-storage technologies, including electrical double-layer capacitors and rechargeable batteries, have attracted significant attention for applications in portable electronic devices, electric vehicles, bulk electricity storage at power stations, and “load leveling” of renewable sources, such as solar energy and wind power. Transforming lithium batteries and electric double-layer capacitors requires a step change in the science underpinning these devices, including the discovery of new materials, new electrochemistry, and an increased understanding of the processes on which the devices depend. The Review will consider some of the current scientific issues underpinning lithium batteries and electric double-layer capacitors.

Challenges Facing Lithium Batteries and Electrical Double‐Layer Capacitors

Dislocations are known to be associated with both physical and electrical degradation mechanisms of AlGaN/GaN-on-Si high electron mobility transistors (HEMTs). We have observed threading dislocation movement toward the gate-edges in AlGaN/GaN-on-Si HEMT under high reverse bias stressing. Stressed devices have higher threading dislocation densities (i.e. ∼5 × 109/cm2) at the gate-edges, as compared to unstressed devices (i.e. ∼2.5 × 109/cm2). Dislocation movement correlates well with high tensile stress (∼1.6 GPa) at the gate-edges, as seen from inverse piezoelectric calculations and x-ray synchrotron diffraction residual stress measurements. Based on Peierls stress calculation, we believe that threading dislocations move via glide in 〈112¯0〉/{11¯00} and 〈112¯0〉/{11¯01} slip systems. This result illustrates the importance of threading dislocation mobility in controlling the reliability of AlGaN/GaN-on-Si HEMTs.

Threading dislocation movement in AlGaN/GaN-on-Si high electron mobility transistors under high temperature reverse bias stressing

InSb thin films on oxidized Si wafers have been recrystallized using a strip heater to generate and scan a narrow molten zone across the film. Grains up to 3 × 10 mm have been produced. Crystallization proceeds in a faceted cellular fashion, the excess solute (Sb) being rejected into subboundaries which often lie along low-index crystallographic directions. A InSb-Sb eutectic structure forms at the subboundaries. The width of the single-crystal InSb between subboundaries is approximately 75 μm. The techniques of planar constriction and sub-boundary entrainment have been extended to InSb for the selection of single grains and the prelocation of subboundaries. This technology of producing InSb thin films on oxidized Si substrates may be extendable to other III-V materials, and could lead to novel device structures through the integration of Si and III-V compound devices on the same substrate.

Zone Melting Recrystallization of InSb Films on Oxidized Si Wafers

During solid-state dewetting of thin single crystal films, film edges retract at a rate that is strongly dependent on their crystallographic orientations. Edges with kinetically stable in-plane orientations remain straight as they retract, while those with other in-plane orientations develop in-plane facets as they retract. Kinetically stable edges have retraction rates that are lower than edges with other orientations and thus determine the shape of the natural holes that form during solid-state dewetting. In this paper, measurements of the retraction rates of kinetically stable edges for single crystal (110) and (100) Ni films on MgO are presented. Relative retraction rates of kinetically stable edges with different crystallographic orientations are observed to change under different annealing conditions, and this accordingly changes the initial shapes of growing holes. The surfaces of (110) and (100) films were also characterized using low energy electron diffraction, and different surface reconstructions were observed under different ambient conditions. The observed surface structures were found to correlate with the observed changes in the relative retraction rates of the kinetically stable edges.

Effect of annealing ambient on anisotropic retraction of film edges during solid-state dewetting of thin single crystal films

Controlled microscale (<50 μm) wavy cracks in silicon nitride thin films have been produced through a simple heating process. The crack paths were controlled by metal patterns under the silicon nitride thin films. Wavy crack characteristics were investigated by changing the metal, metal linewidths, metal thickness, and silicon nitride thickness. We discuss the differences in the characteristics and mechanisms of propagation of wavy cracks formed due to differential thermal expansion and those that result from thermal gradients.

Microscale oscillating crack propagation in silicon nitride thin films

We have modelled the microstructures that result from grain nucleation and growth-to-impingement in two dimensions, using various nucleation and growth conditions. Nucleation conditions include simultaneous nucleation at a fixed number of sites, continuous nucleation at a constant rate per unit of untransformed area, cases in which the nucleation rate declines with time, and cases in which nucleation is excluded in a zone surrounding each pre-existing grain. The growth rate for each grain is taken to be a simple function of the grain radius, either increasing with radius, decreasing with radius, or remaining constant. These different conditions result in markedly different structures, with different geometric and topological properties. We have also modelled the effect of grain boundary migration and grain growth following impingement.

Carl V. Thompson

Papers

Threading dislocation movement in AlGaN/GaN-on-Si high electron mobility transistors under high temperature reverse bias stressing

Zone Melting Recrystallization of InSb Films on Oxidized Si Wafers

Effect of annealing ambient on anisotropic retraction of film edges during solid-state dewetting of thin single crystal films

Microscale oscillating crack propagation in silicon nitride thin films

Development Of Microstructure In Thin Films