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

Electrolytes have been identified as some of the most influential components in the performance of electrochemical supercapacitors (ESs), which include: electrical double-layer capacitors, pseudocapacitors and hybrid supercapacitors. This paper reviews recent progress in the research and development of ES electrolytes. The electrolytes are classified into several categories, including: aqueous, organic, ionic liquids, solid-state or quasi-solid-state, as well as redox-active electrolytes. Effects of electrolyte properties on ES performance are discussed in detail. The principles and methods of designing and optimizing electrolytes for ES performance and application are highlighted through a comprehensive analysis of the literature. Interaction among the electrolytes, electro-active materials and inactive components (current collectors, binders, and separators) is discussed. The challenges in producing high-performing electrolytes are analyzed. Several possible research directions to overcome these challenges are proposed for future efforts, with the main aim of improving ESs' energy density without sacrificing existing advantages (e.g., a high power density and a long cycle-life) (507 references).

A review of electrolyte materials and compositions for electrochemical supercapacitors

Photoinduced motions in azo-containing polymers.

This thesis explores transport phenomena in nanochannels on a chip. Fundamental nanofluidic ionic studies form the basis for novel separation and preconcentration applications for proteomic purposes. The measurements were performed with 50-nm-high 1D nanochannels, which are easily accessible from both sides by two microchannels. Nanometer characteristic apertures were manufactured in the bonded structure of Pyrex-amorphous silicon – Pyrex, in which the thickness of the amorphous silicon layer serves as a spacer to define the height of the nanochannels. The geometry of the nanometer-sized apertures is well defined, which simplifies the modeling of the transport across them. Compared to biological pores, the present nanochannels in Pyrex offer increased stability. Fundamental characteristics of nanometer-sized apertures were obtained by impedance spectroscopy measurements of the nanochannel at different ionic strengths and pH values. A conductance plateau (on a log-log scale) was modeled and measured, establishing due to the dominance of the surface charge density in the nanochannels, which induces an excess of mobile counterions to maintain electroneutrality. The nanochannel conductance can be regulated at low ionic strengths by pH adjustment, and by an external voltage applied on the chip to change the zeta potential. This field-effect allows the regulation of ionic flow which can be exploited for the fabrication of nanofluidic devices. Fluorescence measurements confirm that 50-nm-high nanochannels show an exclusion of co-ions and an enrichment of counterions at low ionic strengths. This permselectivity is related to the increasing thickness of the electrical double layer (EDL) with decreasing salt concentrations, which results in an EDL overlap in an aperture if the height of the nanochannel and the thickness of the EDL are comparable in size. The diffusive transport of charged species and therefore the exclusion-enrichment effect was described with a simple model based on the Poisson-Boltzmann equation. The negatively charged Pyrex surface of the nanometer characteristic apertures can be inversed with chemical surface pretreatments, resulting in an exclusion of cations and an enrichment of anions. When a pressure gradient is applied across the nanochannels, charged molecules are electrostatically rejected at the entrance of the nanometer-sized apertures, which can be used for separation processes. Proteomic applications are presented such as the separation and preconcentration of proteins. The diffusion of Lectin proteins with different isoelectric points and very similar compositions were controlled by regulating the pH value of the buffer. When the proteins are neutral at their pI value, the diffusion coefficient is maximal because the biomolecules does not interact electrostatically with the charged surfaces of the nanochannel. This led to a fast separation of three Lectin proteins across the nanochannel. The pI values measured in this experiment are slightly shifted compared to the values obtained with isoelectric focusing because of reversible adsorption of proteins on the walls which affects the pH value in the nanochannel. An important application in the proteomic field is the preconcentration of biomolecules. By applying an electric field across the nanochannel, anionic and cationic analytes were preconcentrated on the cathodic side of the nanometer-sized aperture whereas on the anodic side depletion of ions was observed. This is due to concentration polarization, a complex of effects related to the formation of ionic concentration gradients in the electrolyte solution adjacent to an ion-selective interface. It was measured that the preconcentration factor increased with the net charge of the molecule, leading to a preconcentration factor of > 600 for rGFP proteins in 9 minutes. Such preconcentrations are important in micro total analysis systems to achieve increased detection signals of analytes contained in dilute solutions. Compared to cylindrical pores, our fabrication process allows the realization of nanochannels on a chip in which the exclusion-enrichment effect and a big flux across the nanometer-sized aperture can be achieved, showing the interest for possible micro total analysis system applications. The described exclusion-enrichment effect as well as concentration polarization play an important role in transport phenomena in nanofluidics. The appendix includes preliminary investigations in DNA molecule separation and fluorescence correlation spectroscopy measurements, which allows investigating the behavior of molecules in the nanochannel itself.

/pdf/transport-phenomena-in-nanofluidics-1di3nwdyom.pdf

Transport phenomena in nanofluidics

Ionic liquids offer a unique suite of properties that make them important candidates for a number of energy related applications. Cation–anion combinations that exhibit low volatility coupled with high electrochemical and thermal stability, as well as ionic conductivity, create the possibility of designing ideal electrolytes for batteries, super-capacitors, actuators, dye sensitised solar cells and thermo-electrochemical cells. In the field of water splitting to produce hydrogen they have been used to synthesize some of the best performing water oxidation catalysts and some members of the protic ionic liquid family co-catalyse an unusual, very high energy efficiency water oxidation process. As fuel cell electrolytes, the high proton conductivity of some of the protic ionic liquid family offers the potential of fuel cells operating in the optimum temperature region above 100 °C. Beyond electrochemical applications, the low vapour pressure of these liquids, along with their ability to offer tuneable functionality, also makes them ideal as CO2 absorbents for post-combustion CO2 capture. Similarly, the tuneable phase properties of the many members of this large family of salts are also allowing the creation of phase-change thermal energy storage materials having melting points tuned to the application. This perspective article provides an overview of these developing energy related applications of ionic liquids and offers some thoughts on the emerging challenges and opportunities.

/pdf/energy-applications-of-ionic-liquids-4xj70drpc5.pdf

Energy applications of ionic liquids

Recent developments in the field of self-assembly of polyelectrolyte multilayers are presented and discussed. Fundamental studies of multilayers on planar or colloidal supports have in the past few years advanced from structural studies towards questions of the internal composition, dynamics, hydration, and interactions in multilayers. This is accompanied by new theoretical concepts and models for the multilayer assembly. Furthermore, in the past years the development of coating procedures onto colloidal templates instead of planar substrates has had a large impact on the field, leading either to the formation of new types of nanostructures, such as hollow shells with large application potential or colloid coating offered additional possibilities for fundamental multilayer studies involving volume methods. Finally, permeability studies are today an essential tool in providing an understanding of transport processes in these semi-permeable membranes, which are essential for applications such as drug encapsulation or membrane separation.

https://www.uni-muenster.de/imperia/md/content/physikalische_chemie/schoenhoff/cocis_2003_rev.pdf

Self-assembled polyelectrolyte multilayers

Freezing and melting of H2O and D2O in the cylindrical pores of well-characterized MCM-41 silica materials (pore diameters from 2.5 to 4.4 nm) was studied by differential scanning calorimetry (DSC) and 1H NMR cryoporometry. Well-resolved DSC melting and freezing peaks were obtained for pore diameters down to 3.0 nm, but not in 2.5 nm pores. The pore size dependence of the melting point depression ΔTm can be represented by the Gibbs–Thomson equation when the existence of a layer of nonfreezing water at the pore walls is taken into account. The DSC measurements also show that the hysteresis connected with the phase transition, and the melting enthalpy of water in the pores, both vanish near a pore diameter D* ≈ 2.8 nm. It is concluded that D* represents a lower limit for first-order melting/freezing in the pores. The NMR spin echo measurements show that a transition from low to high mobility of water molecules takes place in all MCM-41 materials, including the one with 2.5 nm pores, but the transition revealed by NMR occurs at a higher temperature than indicated by the DSC melting peaks. The disagreement between the NMR and DSC transition temperatures becomes more pronounced as the pore size decreases. This is attributed to the fact that with decreasing pore size an increasing fraction of the water molecules is situated in the first and second molecular layers next to the pore wall, and these molecules have slower dynamics than the molecules in the core of the pore.

https://www.uni-muenster.de/imperia/md/content/physikalische_chemie/schoenhoff/pccp_08_mcm.pdf

Melting and freezing of water in cylindrical silica nanopores

Multilayers of charged polymers can be formed by the alternating adsorption of polyanions and polycations. By this so-called layer-by-layer self-assembly method, planar surfaces or colloidal templates can be coated. This method is reviewed here with respect to the basic physical principles governing multilayer formation. Particular emphasis is put on the adsorption process of a single polyelectrolyte layer to a multilayer surface as the process controlling the charge complexation and the local molecular structure. Then, the implications for the properties of the multilayer assembly are discussed. In particular, molecular properties such as the internal stoichiometry, the local interactions, and the conformation on a molecular scale are reviewed.

https://www.uni-muenster.de/imperia/md/content/physikalische_chemie/schoenhoff/jop_03_rev.pdf

Layered polyelectrolyte complexes: physics of formation and molecular properties

spectroscopy and pulsed field gradient NMR Molar ratios x ) nLi-TFSI/(nLi-TFSI + nBMP-TFSI) up to 0377 could be achieved without crystallization From the bulk ionic conductivity and the individual diffusion coefficients of cations and anions we calculate the Haven ratio and the apparent lithium transference number Although the Haven ratio exhibits typical values for ionic liquid electrolytes, the maximal apparent lithium transference number is higher than found in other recent studies on ionic liquid electrolytes containing lithium ions On the basis of these results we discuss strategies for further improving the lithium transference number of such electrolytes

https://www.uni-muenster.de/imperia/md/content/physikalische_chemie/schoenhoff/jpcb_08_il.pdf

Enhanced lithium transference numbers in ionic liquid electrolytes.

http://bio.ph.tum.de/uploads/media/Colloids_Hydration_and_internal_Schoenhoff.pdf

Monika Schönhoff

Papers

Self-assembled polyelectrolyte multilayers

Melting and freezing of water in cylindrical silica nanopores

Layered polyelectrolyte complexes: physics of formation and molecular properties

Enhanced lithium transference numbers in ionic liquid electrolytes.

Hydration and internal properties of polyelectrolyte multilayers