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

Crystalline metal-organic frameworks (MOFs) are formed by reticular synthesis, which creates strong bonds between inorganic and organic units. Careful selection of MOF constituents can yield crystals of ultrahigh porosity and high thermal and chemical stability. These characteristics allow the interior of MOFs to be chemically altered for use in gas separation, gas storage, and catalysis, among other applications. The precision commonly exercised in their chemical modification and the ability to expand their metrics without changing the underlying topology have not been achieved with other solids. MOFs whose chemical composition and shape of building units can be multiply varied within a particular structure already exist and may lead to materials that offer a synergistic combination of properties.

The Chemistry and Applications of Metal-Organic Frameworks

This critical review will be of interest to the experts in porous solids (including catalysis), but also solid state chemists and physicists. It presents the state-of-the-art on hybrid porous solids, their advantages, their new routes of synthesis, the structural concepts useful for their ‘design’, aiming at reaching very large pores. Their dynamic properties and the possibility of predicting their structure are described. The large tunability of the pore size leads to unprecedented properties and applications. They concern adsorption of species, storage and delivery and the physical properties of the dense phases. (323 references)

Hybrid porous solids: past, present, future

New materials capable of storing hydrogen at high gravimetric and volumetric densities are required if hydrogen is to be widely employed as a clean alternative to hydrocarbon fuels in cars and other mobile applications. With exceptionally high surface areas and chemically-tunable structures, microporous metal–organic frameworks have recently emerged as some of the most promising candidate materials. In this critical review we provide an overview of the current status of hydrogen storage within such compounds. Particular emphasis is given to the relationships between structural features and the enthalpy of hydrogen adsorption, spectroscopic methods for probing framework–H2 interactions, and strategies for improving storage capacity (188 references).

/pdf/hydrogen-storage-in-metal-organic-frameworks-9ols7xj8jh.pdf

Hydrogen storage in metal–organic frameworks

Metal-organic framework-5 (MOF-5) of composition Zn4O(BDC)3 (BDC = 1,4-benzenedicarboxylate) with a cubic three-dimensional extended porous structure adsorbed hydrogen up to 4.5 weight percent (17.2 hydrogen molecules per formula unit) at 78 kelvin and 1.0 weight percent at room temperature and pressure of 20 bar. Inelastic neutron scattering spectroscopy of the rotational transitions of the adsorbed hydrogen molecules indicates the presence of two well-defined binding sites (termed I and II), which we associate with hydrogen binding to zinc and the BDC linker, respectively. Preliminary studies on topologically similar isoreticular metal-organic framework-6 and -8 (IRMOF-6 and -8) having cyclobutylbenzene and naphthalene linkers, respectively, gave approximately double and quadruple (2.0 weight percent) the uptake found for MOF-5 at room temperature and 10 bar.

/pdf/hydrogen-storage-in-microporous-metal-organic-frameworks-2xcgwp5q23.pdf

Hydrogen Storage in Microporous Metal-Organic Frameworks

Publisher Summary In view of the growing interest in the field, this chapter discusses the developing reliable computer-simulations procedures that can be used to complement and enhance the analysis of experimental data, such as thermodynamic, spectroscopic and structural measurements. In the context of chlorocarbons, for example, the main vehicles for study have been chloroform, trichloroethylene, and tetrachloroethylene, these molecules being the most abundant in ground water and aquifer contamination. The chapter focuses primarily on halocarbons in faujasite (FAU) systems, a choice based upon (i) the availability of FAUs in a variety of Si/Al ratios and cation forms, (ii) their large apertures (∼7.5 A) and sorption capacities, and (iii) their commercial availability at modest cost.

Adsorption of halocarbons in nanoporous materials: current status and future challenges

Neutron spectroscopy of localized modes in CeD2−xHy

The authors report the results of the effect of static pressure on the Raman spectrum of TATB up to pressures of 160 kbar and deuterated TATB (DTATB) up to pressures of 65 kbar. Both these solids are found to be remarkably stable to high densities. Unusual pressure dependence of the [delta][sub NO[sub 2]], [nu][sub C-N], and [nu][sub N-O] modes is observed and attributed to variation in NH[sub 2]/NO[sub 2] coupling as the pressure is increased. Both of these aspects of TATB may be important in contributing to the insensitivity of TATB to shock-initiated detonation. The authors also find that, unlike at ambient pressures, TATB is quite insensitive to photolysis when exposed to static pressures exceeding 15 kbar, indicating that photolysis of TATB involves a positive activation volume. In addition, the authors present inelastic neutron scattering data as well as some assignments of TATB and two related substituted anilines, p-nitroaniline and p-chloroaniline. These clearly demonstrate the strong vibrational coupling between NH[sub 2] and NO[sub 2] groups.

High‐Pressure Raman Scattering and Inelastic Neutron Scattering Studies of Triaminotrinitrobenzene

Determined the type of metal site which interacts • most strongly with hydrogen by carrying out systematic studies of various types of metal binding sites in zeolites and coordination polymers. Investigated intra-framework metal sites in analogs • of MOF-74 with Co and Mg substituted for Zn, by inelastic neutron scattering (INS) of the adsorbed H2, and found Mg to have the strongest interaction among these metals. Demonstrated the existence of coordinated • molecular hydrogen at an open, and highly accessible metal binding site in Cu-ZSM-5. Confirmed evidence for possible binding of two • hydrogen molecules at Cu(I) sites in Cu-ZSM-5. Completed our investigation of the synthesis • of hybrids with a highly functionalized link, 2,5-thiazolo[5,4-d]thiazoledicarboxylic acid, and several series of metals, including alkai, alkaline earths and first row transition metals, which did not yield a material with appreciable porosity. Synthesized a total of 18 new hybrid metal organic • frameworks (MOFs) with fluorine-substituted organic linkers. Obtained a new hybrid material with a • tetrafluoroterephthalate, zinc, and 1,2-bis(4-pyridyl) ethane with substantial porosity. INS studies of H • 2 in Zn(1,2,4-triazolate) (tetrafluoroterephthalate) reveal three strong binding sites, with interaction much greater than typical MOFs, and serve to understand the relatively high isosteric heat of adsorption of 8 kJ/mol over a wide range of loadings.

https://www.hydrogen.energy.gov/pdfs/progress08/iv_d_2_eckert.pdf

Juergen Eckert

Papers

Adsorption of halocarbons in nanoporous materials: current status and future challenges

Neutron spectroscopy of localized modes in CeD2−xHy

High‐Pressure Raman Scattering and Inelastic Neutron Scattering Studies of Triaminotrinitrobenzene

IV.D.2 Hydrogen Storage Materials with Binding Intermediate between Physisorption and Chemisorption

Mutual interactions in a ternary protein/bioprotectant/water system