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 emergence of order in natural systems is a constant source of inspiration for both physical and biological sciences. While the spatial order characterizing for example the crystals has been the basis of many advances in contemporary physics, most complex systems in nature do not offer such high degree of order. Many of these systems form complex networks whose nodes are the elements of the system and edges represent the interactions between them. 
Traditionally complex networks have been described by the random graph theory founded in 1959 by Paul Erdohs and Alfred Renyi. One of the defining features of random graphs is that they are statistically homogeneous, and their degree distribution (characterizing the spread in the number of edges starting from a node) is a Poisson distribution. In contrast, recent empirical studies, including the work of our group, indicate that the topology of real networks is much richer than that of random graphs. In particular, the degree distribution of real networks is a power-law, indicating a heterogeneous topology in which the majority of the nodes have a small degree, but there is a significant fraction of highly connected nodes that play an important role in the connectivity of the network. 
The scale-free topology of real networks has very important consequences on their functioning. For example, we have discovered that scale-free networks are extremely resilient to the random disruption of their nodes. On the other hand, the selective removal of the nodes with highest degree induces a rapid breakdown of the network to isolated subparts that cannot communicate with each other. 
The non-trivial scaling of the degree distribution of real networks is also an indication of their assembly and evolution. Indeed, our modeling studies have shown us that there are general principles governing the evolution of networks. Most networks start from a small seed and grow by the addition of new nodes which attach to the nodes already in the system. This process obeys preferential attachment: the new nodes are more likely to connect to nodes with already high degree. We have proposed a simple model based on these two principles wich was able to reproduce the power-law degree distribution of real networks. Perhaps even more importantly, this model paved the way to a new paradigm of network modeling, trying to capture the evolution of networks, not just their static topology.

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Statistical mechanics of complex networks

Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

The Theory of Island Biogeography

http://www.maths.qmul.ac.uk/%7Elatora/report_06.pdf

Complex networks: Structure and dynamics

https://www.tau.ac.il/%7Eklafter1/258.pdf

The random walk's guide to anomalous diffusion: a fractional dynamics approach

The nonadiabatic effects due to the breakdown of Migdal's theorem in high-$T_c$ superconductors are strongly affected by the opening of the superconducting gap. Here we report how the momentum-frequency dependence of vertex corrections is modified by the gap. A general effect is that the positive region of the vertex corrections is increased leading to an enhancement of their relevance. This has a number of physical consequences that we discuss in details in relation to specific experiments.

Role of the superconducting gap opening on vertex corrections

Galaxies and clusters distributions show two major properties: (i) the positions of galaxies and clusters are characterized by a power law distribution indicating properties with respect to their positions. (ii) The distribution of masses is also characterized by a power law corresponding to self similarity of different nature. These two properties are naturally unified by the concept of multifractality. This concept naturally arises if the distribution of matter, as given by both positions and masses, has self similar properties. We discuss the experimental situation in this respect and we introduce a simple stochastic model based of the aggregation process of particles The aim of this model is to understand which characteristic properties of the aggregation probability can gives rise to multifractal distribution In particular we find that a crucial element in this respect is that the aggregation probability should depend on the environment of the aggregation region.

Multifractal properties of visible matter distribution: A Stochastic model

High-Tc superconductors are usually described as strongly correlated electronic systems. This feature deeply affects the one-particle and two-particle properties of the system. In particular, a large incoherent background developes on the top of a narrow quasi-particle peak in the one-electron spectral function. We schematize this structure with a simple phenomenological form. The corresponding Green's function is employed to calculate the charge response of the system taking into account in a proper way strong correlation effects. The effective charge interaction acquires a structure in the exchanged momentum space with a predominance of forward scattering, in agreement with previous numerical calculations. The consequences of the momentum dependence of the interaction are discussed in the framework of the nonadiabatic theory of superconductivity proposed for the high-Tc materials.

Effect of strong correlation on the electron-phonon interaction

We discuss the compatibility of the most accurate experimental data with the ordinary Migdal-Eliashberg theory of superconductivity in the fullerene compound Rb_3C_60. By using different model phonon spectra we conclude that the experimental data can be fitted only by invoking an electron-phonon coupling of order \lambda\simeq 3. This exceedingly high value is unphysical and it is not consistent with the basic assumptions of the Migdal-Eliashberg theory. On the contrary, by relaxing the adiabatic hypothesis on which the Migdal-Eliashberg theory rests, the experimental data can be fitted by much more realistic values of \lambda. This generalized theory predicts also characteristic features absent in the Migdal-Eliashberg framework which can be experimentally tested.

http://arxiv.org/pdf/cond-mat/0006398.pdf

Failure of the Migdal-Eliashberg Theory of Superconductivity in Rb_3C_60

In C 60 compounds the frequencies of the phonon involved in the superconductive processes (intra-molecular modes with ω ph up to 2300 K) are comparable with the typical electronic scale ( E F =2900 K) and thus the two dynamics cannot be treated separately (breakdown of the adiabatic hypothesis). This implies a generalization of the standard theory to include nonadiabatic effects. The strong electronic correlation in the fullerenes causes the contribution of the nonadiabatic processes to be positive with consequent increase of the effective electron–phonon (el–ph) pairing λ and of T c . We show that the inclusion of nonadiabatic terms in the el–ph interaction is a key element for the high values of T c in fullerenes. In particular T c as high as 100 K are shown to be compatible with moderate values of λ ≲1. This implies that it should be possible to increase the value of λ , and so T c , and still have a stable system.

Luciano Pietronero

Papers

Role of the superconducting gap opening on vertex corrections

Multifractal properties of visible matter distribution: A Stochastic model

Effect of strong correlation on the electron-phonon interaction

Failure of the Migdal-Eliashberg Theory of Superconductivity in Rb_3C_60

Unconventional pairing in fullerides by nonadiabatic channels