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’

Note: Times Cited: 875 Reference EPFL-ARTICLE-206025doi:10.1021/cr0501846View record in Web of Science URL: ://WOS:000249839900009 Record created on 2015-03-03, modified on 2017-05-12

Complex Hydrides for Hydrogen Storage

: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Noncovalent interactions: a challenge for experiment and theory

High-resolution spectroscopy of cluster ions.

The spring constant of an atomic force microscope cantilever is often needed for quantitative measurements. The calibration method of Sader et al. [Rev. Sci. Instrum. 70, 3967 (1999)]10.1063/1.1150021 for a rectangular cantilever requires measurement of the resonant frequency and quality factor in fluid (typically air), and knowledge of its plan view dimensions. This intrinsically uses the hydrodynamic function for a cantilever of rectangular plan view geometry. Here, we present hydrodynamic functions for a series of irregular and non-rectangular atomic force microscope cantilevers that are commonly used in practice. Cantilever geometries of arrow shape, small aspect ratio rectangular, quasi-rectangular, irregular rectangular, non-ideal trapezoidal cross sections, and V-shape are all studied. This enables the spring constants of all these cantilevers to be accurately and routinely determined through measurement of their resonant frequency and quality factor in fluid (such as air). An approximate formulation of the hydrodynamic function for microcantilevers of arbitrary geometry is also proposed. Implementation of the method and its performance in the presence of uncertainties and non-idealities is discussed, together with conversion factors for the static and dynamic spring constants of these cantilevers. These results are expected to be of particular value to the design and application of micro- and nanomechanical systems in general.

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Spring constant calibration of atomic force microscope cantilevers of arbitrary shape

The van der Waals vibrations of aniline–, phenol–, fluorobenzene–, and chlorobenzene–Ar1 complexes have been measured using one‐color resonance enhanced multiphoton ionization spectroscopy, together with time‐of‐flight mass spectrometry, in a skimmed supersonic molecular beam. A delayed ionization extraction technique is used to suppress contributions to the spectra from dissociating complexes. The S1–S0 electronic origins for the van der Waals complexes are found to be shifted towards lower energy (red shift) relative to the parent molecule electronic origin for all the Ar1 complexes. The red shifts increase in magnitude in the order: fluorobenzene, chlorobenzene, phenol, aniline. Progressions, overtones and combination transitions involving the low frequency van der Waals vibrations, i.e., the symmetric bend (bx), the asymmetric bend (by) and the stretch (sz) are observed clearly in the S1←S0 excitation spectra. Intensity profiles are found to deviate substantially from those expected on the basis of ha...

Stretch–bend coupling between van der Waals modes in the S1 state of substituted benzene–Ar1 complexes

Spectroscopic and dynamical properties of the Ar,,-HCO+ ( n = 1 13) cluster series have been explored by exciting the chromophore HCO+ in the vicinity of its Y I C-H stretch transition. Spectra were obtained by mass selecting the clusters, exposing them to tunable, pulsed IR light (0.02 cm-' bandwidth), and monitoring the fragment intensity as a function of laser frequency. The V I band of the Ar-HCO+ dimer is rotationally resolved and has a form consistent with a linear proton-bound complex. Analysis in terms of a pseudodiatomic Hamiltonian yields the following parameters: YO = 2815.063 f 0.020 cm-', B\" = 0.06646 f 0.000 08 cm-', D\" = (7 i 4) x cm-I, B' = 0.06829 f 0.000 08 cm-', D' = (17 f 4) x lo-* cm-'. The rotational line widths indicate a lifetime of more than 250 ps for the optically prepared state. The V I vibrational bands of the larger Ar,-HCO+ clusters, while lacking resolved rotational structure, are still reasonably narrow (< 10 cm-I) and decrease in width as the cluster size increases. Excitation of the V I transition in Ar,-HCO' ( n = 213) results in the production of a relatively narrow range of daughter ions. Incremental Ar binding energies are extracted from the branching ratio data using a statistical model which takes into account the kinetic energy of the departing Ar atoms. The variation with cluster size of the binding energies, vibrational band shifts, and combination band spacings are argued to be evidence for Ar,?-HCO+ structures where Ar atoms form primary and secondary solvation rings about a linear Ar-HCO+ core with shell completion at n = 12. This view is consistent with simple empirical potential energy calculations.

Size Effects in Cluster Infrared Spectra: the .nu.1 Band of Arn-HCO+ (n = 1-13)

Ionic clusters are ubiquitous in all gas-phase environments, being particularly abundant in plasmas, flames, and the terrestrial atmosphere and are also likely constituents of the interstellar medium Ion-induced dipole and ion-dipole forces result in bonded entities whose dissociation energies lie between those of van der Waals and fully chemically bound species They also serve as convenient systems to investigate liquid-phase structures surrounding a solvated ion This review is primarily devoted to discussing the spectroscopic characterization of relatively weakly bound ionic complexes It concentrates on results obtained for quite disparate chemical species including metal ions solvated by noble gas, water or inorganic molecular ligands, protonated hydrogen, ammonia and water complexes, inorganic molecular chromophores such as N[sub 2][sup +] surrounded by rare gas atoms, and aromatic rings with one or more rare gas atoms attached The focus of this review is on spectroscopic studies that provide direct evidence to structure The authors do not consider the considerable body of experimental and theoretical work concerned with bound-free electronic transition in ionic complexes Generally cation complexes consisting of two like moieties, one minus an electron, have one bound and one repulsive electronic state correlating with ground-sate fragments Although observation of transitions between these twomore » states leads to limited structural information on the ground state of the complex, it is possible to determine binding energies and the symmetry of the transition by measuring the angular and kinetic energy distributions of the fragments 192 refs« less

Evan J. Bieske

Papers

High-resolution spectroscopy of cluster ions.

Spring constant calibration of atomic force microscope cantilevers of arbitrary shape

Stretch–bend coupling between van der Waals modes in the S1 state of substituted benzene–Ar1 complexes

Size Effects in Cluster Infrared Spectra: the .nu.1 Band of Arn-HCO+ (n = 1-13)

Spectroscopic studies of ionic complexes and clusters