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

The surface science of titanium dioxide

Nanoparticles: Properties, applications and toxicities

The Interaction of Water with Solid Surfaces: Fundamental Aspects Revisited

A surface science perspective on TiO2 photocatalysis

By means of synchrotron radiation photoemission spectroscopy, we have investigated the adsorption and desorption processes of the ${\mathrm{SO}}_{2}$ molecule on a rutile ${\mathrm{TiO}}_{2}(110)\ensuremath{-}(1\ifmmode\times\else\texttimes\fi{}1)$ surface. We have recorded the $\mathrm{S}2p$ core-level photoemission peaks for different ${\mathrm{SO}}_{2}$ exposures at a substrate temperature of 120 K in order to get information about the divers species formed on the surface. We have also recorded real-time photoemission spectra to study the adsorption from the early stages to large exposures and to follow the chemical transformations occurring with the adsorbed species as the temperature increases. We have seen that the first arriving molecules react with the oxygen atoms of the surface forming ${\mathrm{SO}}_{x}$ species, both at low and room temperature. Doses higher than the saturation dose (6 L) lead to the dissociation of the molecule generating adsorbed S. ${\mathrm{SO}}_{2}$ multilayer has been found for exposures higher than around 250 L. We have found a progressive reduction of the ${\mathrm{SO}}_{x}$ species with the temperature and the formation of sulphide as the most stable phase. We have not found any signature of molecular ordered species at the interface.

Adsorption and desorption of SO 2 on the TiO 2 (110)-(1×1) surface: A photoemission study

The influence of implanted silicon, molybdenum and cerium on the oxidation behaviour of a 18Cr8Ni stainless steel was studied at 1173 K up to 144 h in air under isothermal conditions in order to verify the enhanced selective oxidation of chromium by these elements. The implanted surface and the corrosion products formed were characterized by means of AES, SEM, EDS and XRD. Implanted depth profiles were calculated by TRIM96 computational code. The implanted silicon and cerium markedly improved protection against oxidation of the alloy by enhanced chromium transport while molybdenum gave rise to an accelerated oxidation due to the formation of volatile MoO 3 species. Further, ion implantation was found to play a beneficial effect against decarburization of the alloy.

High temperature corrosion protection of austenitic AISI 304 stainless steel by Si, Mo and Ce ion implantation

Characterization of MgO thin films grown by rf-sputtering

The knowledge of the oxidation state of the transition metal cations in Sr2FeMO6 (M = W, Mo, Re and Sb) double perovskites is of paramount importance to understand their appealing magnetoresistive or magnetic properties. We present a systematic investigation of the valences of Fe, W, Mo, Re and Sb cations in these perovskites using three different and complementary techniques of analysis. We have used a diffraction method, neutron powder diffraction (NPD), coupled with the bond-valence model; and two spectroscopy methods, X-ray photoemission spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). These two techniques are also complementary since XPS analyses the surface of the samples whereas XAS probes the bulk material. The analysis of the Fe K-edge spectra of the four samples shows a clear shift of the Fe K-edge as the valence of iron increases in the sequence M = W, Mo, Re and Sb. In addition, XANES pre-edge structures unveil a progressive reduction in the occupancy level of the Fe-3d band as the oxidation state of iron increases along the sequence M = W, Mo, Re and Sb. Finally, XANES computations have determined the electronic structures of Sr2FeWO6, Sr2FeMoO6, Sr2FeReO6 and Sr2FeSbO6.

E. Román

Papers

Adsorption and desorption of SO 2 on the TiO 2 (110)-(1×1) surface: A photoemission study

High temperature corrosion protection of austenitic AISI 304 stainless steel by Si, Mo and Ce ion implantation

Characterization of MgO thin films grown by rf-sputtering

Study of the valence state and electronic structure in Sr2FeMO6 (M = W, Mo, Re and Sb) double perovskites

A study of photon-induced processes with adsorption-desorption of glycine at the TiO2(110)(1×2) surface