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

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

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

Diamond-like carbon (DLC) is a metastable form of amorphous carbon with significant sp3 bonding. DLC is a semiconductor with a high mechanical hardness, chemical inertness, and optical transparency. This review will describe the deposition methods, deposition mechanisms, characterisation methods, electronic structure, gap states, defects, doping, luminescence, field emission, mechanical properties and some applications of DLCs. The films have widespread applications as protective coatings in areas, such as magnetic storage disks, optical windows and micro-electromechanical devices (MEMs).

/pdf/diamond-like-amorphous-carbon-3pczopr0z7.pdf

Diamond-like amorphous carbon

Rapid progress in the synthesis and processing of materials with structure on nanometer length scales has created a demand for greater scientific understanding of thermal transport in nanoscale devices, individual nanostructures, and nanostructured materials. This review emphasizes developments in experiment, theory, and computation that have occurred in the past ten years and summarizes the present status of the field. Interfaces between materials become increasingly important on small length scales. The thermal conductance of many solid–solid interfaces have been studied experimentally but the range of observed interface properties is much smaller than predicted by simple theory. Classical molecular dynamics simulations are emerging as a powerful tool for calculations of thermal conductance and phonon scattering, and may provide for a lively interplay of experiment and theory in the near term. Fundamental issues remain concerning the correct definitions of temperature in nonequilibrium nanoscale systems. Modern Si microelectronics are now firmly in the nanoscale regime—experiments have demonstrated that the close proximity of interfaces and the extremely small volume of heat dissipation strongly modifies thermal transport, thereby aggravating problems of thermal management. Microelectronic devices are too large to yield to atomic-level simulation in the foreseeable future and, therefore, calculations of thermal transport must rely on solutions of the Boltzmann transport equation; microscopic phonon scattering rates needed for predictive models are, even for Si, poorly known. Low-dimensional nanostructures, such as carbon nanotubes, are predicted to have novel transport properties; the first quantitative experiments of the thermal conductivity of nanotubes have recently been achieved using microfabricated measurement systems. Nanoscale porosity decreases the permittivity of amorphous dielectrics but porosity also strongly decreases the thermal conductivity. The promise of improved thermoelectric materials and problems of thermal management of optoelectronic devices have stimulated extensive studies of semiconductor superlattices; agreement between experiment and theory is generally poor. Advances in measurement methods, e.g., the 3ω method, time-domain thermoreflectance, sources of coherent phonons, microfabricated test structures, and the scanning thermal microscope, are enabling new capabilities for nanoscale thermal metrology.

/pdf/nanoscale-thermal-transport-1frv881kzm.pdf

Nanoscale thermal transport

Semicrystalline structures involving molecular packing and optimized chain conformations of three polyimides [N(CO) 2 Ph(CO) 2 N-X] n (X= PhOPh, Ph) [N(CO) 2 Ph-Ph(CO) 2 N-Ph] n have been obtained with the CHARMM molecular-dynamics program, and their densities calculated. An eclipsed conformation of face-to-face stacking of polymer chains with a relative shift is observed, and the shift is found to depend upon the molecular characteristics of the planar unit and chain linearity. Three-dimensional structures obtained by calculating the optimized edge-on conformation of the stacked units yield the smallest calculated density for PMDA-ODA, namely 1.515 g/cm 3 , followed by BPDA-PDA with 1.644 g/cm 3 and PMDA-PDA with 1.712 g/cm 3

/pdf/simulated-crystalline-structures-of-aromatic-polyimides-2rcr00pu0f.pdf

Simulated crystalline structures of aromatic polyimides

Stress-Induced Phenomena In Metallization

Grain‐boundary diffusivities of a Sn119 radioactive tracer have been measured in polycrystalline Pb specimens in the temperature range 70–200 °C. The combined diffusion parameter δDb is expressed by the Arrhenius relation δDb = 7.3×10−9 exp(−0.41±0.02 eV/kT) (cm3/sec). The Sn impurity diffusivities are larger than Pb self‐diffusivities in the grain boundaries, which has been confirmed by codiffusion measurements of the two species. The lattice diffusivities reported in the literature for the Sn and Pb tracers also show a similar trend. In both situations the effect appears to be related to the physical characteristics of the two diffusing species.

Grain-boundary diffusion of Sn in Pb

https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=854130

Small angle X-ray scattering measurements of spatial dependent linewidth in dense nanoline gratings ☆

Metal-organic substrate adhesion is improved by irradiating the substrate with low energy reactive ions, electrons, or photons to alter the chemical composition of a surface layer of the substrate to a depth of from about 1 nm to a few tens of nanometers. The energy of the incident reactive ions and electrons can be in the range of about 50 to 2000 eV, while the energy of the incident photons can be in the range of about 0.2 -500 eV. Irradiation of the substrate can occur prior to or during metal deposition. For simultaneous metal deposition/particle irradiation, the arrival rates of the metal atoms and the substrate treatment particles are within a few orders of magnitude of one another. The low energy irradiation can be conducted at room temperature or elevated temperatures.

Paul S. Ho

Papers

Simulated crystalline structures of aromatic polyimides

Stress-Induced Phenomena In Metallization

Grain-boundary diffusion of Sn in Pb

Small angle X-ray scattering measurements of spatial dependent linewidth in dense nanoline gratings ☆

A method of metallising an organic substrate so as to achieve improved adhesion of the metal