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

Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

Gold nanoparticles: assembly, supramolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology.

Use of amphiphilic triblock copolymers to direct the organization of polymerizing silica species has resulted in the preparation of well-ordered hexagonal mesoporous silica structures (SBA-15) with uniform pore sizes up to approximately 300 angstroms. The SBA-15 materials are synthesized in acidic media to produce highly ordered, two-dimensional hexagonal (space group p6mm) silica-block copolymer mesophases. Calcination at 500°C gives porous structures with unusually large interlattice d spacings of 74.5 to 320 angstroms between the (100) planes, pore sizes from 46 to 300 angstroms, pore volume fractions up to 0.85, and silica wall thicknesses of 31 to 64 angstroms. SBA-15 can be readily prepared over a wide range of uniform pore sizes and pore wall thicknesses at low temperature (35° to 80°C), using a variety of poly(alkylene oxide) triblock copolymers and by the addition of cosolvent organic molecules. The block copolymer species can be recovered for reuse by solvent extraction with ethanol or removed by heating at 140°C for 3 hours, in both cases, yielding a product that is thermally stable in boiling water.

Triblock copolymer syntheses of mesoporous silica with periodic 50 to 300 angstrom pores

Problems associated with large-scale pattern growth of graphene constitute one of the main obstacles to using this material in device applications. Recently, macroscopic-scale graphene films were prepared by two-dimensional assembly of graphene sheets chemically derived from graphite crystals and graphene oxides. However, the sheet resistance of these films was found to be much larger than theoretically expected values. Here we report the direct synthesis of large-scale graphene films using chemical vapour deposition on thin nickel layers, and present two different methods of patterning the films and transferring them to arbitrary substrates. The transferred graphene films show very low sheet resistance of approximately 280 Omega per square, with approximately 80 per cent optical transparency. At low temperatures, the monolayers transferred to silicon dioxide substrates show electron mobility greater than 3,700 cm(2) V(-1) s(-1) and exhibit the half-integer quantum Hall effect, implying that the quality of graphene grown by chemical vapour deposition is as high as mechanically cleaved graphene. Employing the outstanding mechanical properties of graphene, we also demonstrate the macroscopic use of these highly conducting and transparent electrodes in flexible, stretchable, foldable electronics.

Large-scale pattern growth of graphene films for stretchable transparent electrodes

The carrier collection efficiency (ηc) and energy conversion efficiency (ηe) of polymer photovoltaic cells were improved by blending of the semiconducting polymer with C60 or its functionalized derivatives. Composite films of poly(2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene) (MEH-PPV) and fullerenes exhibit ηc of about 29 percent of electrons per photon and ηe of about 2.9 percent, efficiencies that are better by more than two orders of magnitude than those that have been achieved with devices made with pure MEH-PPV. The efficient charge separation results from photoinduced electron transfer from the MEH-PPV (as donor) to C60 (as acceptor); the high collection efficiency results from a bicontinuous network of internal donor-acceptor heterojunctions.

/pdf/polymer-photovoltaic-cells-enhanced-efficiencies-via-a-2lwj3yarfe.pdf

Polymer photovoltaic cells : enhanced efficiencies via a network of internal donor-acceptor heterojunctions

Room Temperature Growth of Mesoporous Silica Fibers: A New High‐ Surface‐Area Optical Waveguide.

Variable-temperature synchrotron x-ray powder diffraction data from dehydrated Na6[Al6Si6O24] reveal a structural phase transition that involves both the commensurate ordering of the extra-framework Na cations and a one-dimensional incommensurate modulation of the framework. Peak splittings and superlattice reflections implicate an orthorhombically-distorted volume-doubled supercell at room temperature (a=12.9432 A, b=12.8403 A, and c=9.1372 A) ∼(√a×√a×a). These data also included additional superlattice peaks associated with an incommensurate long-period modulation with τ=(3/2 1/2 1)/8.9. All unique orderings of the 12 Na cations among the 16 available sites of the commensurate supercell are enumerated. A unique solution is identified that minimizes the structural energy and accounts for the observed superlattice peaks. Rietveld analysis reveals a significant Pauling “partial-collapse” tilt angle in the cation-ordered phase, that appears to decrease with increasing temperature.

/pdf/the-cation-vacancy-ordering-transition-in-dehydrated-na6-1no9e5qtcu.pdf

The cation-vacancy ordering transition in dehydrated Na6 sodalite

Ordered mesoporous materials (OMMs) with well-defined pore sizes (>2 nm) and pore geometries are important in various applications that require fast mass transfer or deal with large molecules. Extensive research has resulted in the discovery of OMMs with three types of mesostructures: (i) bi- or multicontinuous, (ii) columnar, and (iii) discontinuous (cagelike). However, another type, the pillared lamellar structure, which has long been sought and has been mathematically computed and known to exist in the research fields of surfactant and multiblock-copolymer mesophases, still remains a mesostructure that has not been observed in real OMMs for any specific symmetry. Herein, we report an unprecedented type of ordered mesoporous material with a hexagonally pillared lamellar (HPL) structure (P63/mmc) that can be synthesized via a phase transformation from a lamellar mesophase by hydrothermal reaction in the presence of an organosilica precursor and a high concentration of a designed Gemini surfactant (Gem16−...

Periodic mesoporous organosilica with a hexagonally pillared lamellar structure.

The C, N, and O core-valence-valence Auger spectra of CO, NO, Co(CO)/sub 3/NO, Fe(CO)/sub 5/, and Mo(CO)/sub 6/ were theoretically analyzed in this report. These spectra are shown to have a qualitative chemical interpretation in terms of ground-state molecular orbital (MO) descriptions. The involvement of both core and valence electrons in the Auger process causes a sensitivity to the valence electron density in the immediate vicinity of the atom containing the initial core hole. As a result, the variation in relative intensity of transitions for different atomic sites in a molecule is a measure of the polarization of the orbital electron density distribution. The nitrogen and oxygen spectra of NO are far more similar than the carbon and oxygen spectra of CO, reflecting a more equal electron density distribution of the valence MO's. Another major difference between the spectra of NO and CO is the presence of peaks corresponding to transitions involving the 2..pi.. level of NO. A common fingerprint carbon Auger spectrum is obtained for the metal carbonyls that is independent of the central metal atom. Theoretical analysis of the carbonyl Auger spectra, which are directly sensitive to the local-valence charge density, indicates that ab initio Hartree-Fock calculations performedmore » with double-zeta basis sets predict an electron density that is in agreement with the experimental Auger results. The assignment of the lowest energy and highest amplitude C(ls/sup -1/) core-hole state in carbonyls (the subject of some recent debate) was checked as different Auger initial states lead to very different Auger line shapes. It is found that the adiabatically relaxed state (as opposed to a shakeup state) dominates.« less

Galen D. Stucky

Papers

Room Temperature Growth of Mesoporous Silica Fibers: A New High‐ Surface‐Area Optical Waveguide.

The cation-vacancy ordering transition in dehydrated Na6 sodalite

Periodic mesoporous organosilica with a hexagonally pillared lamellar structure.

Auger line-shape studies of the bonding in transition metal carbonyls and nitrosyls

Preparation of Hard Mesoporous Silica Spheres.