다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

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

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

A comprehensive review of spatiotemporal pattern formation in systems driven away from equilibrium is presented, with emphasis on comparisons between theory and quantitative experiments. Examples include patterns in hydrodynamic systems such as thermal convection in pure fluids and binary mixtures, Taylor-Couette flow, parametric-wave instabilities, as well as patterns in solidification fronts, nonlinear optics, oscillatory chemical reactions and excitable biological media. The theoretical starting point is usually a set of deterministic equations of motion, typically in the form of nonlinear partial differential equations. These are sometimes supplemented by stochastic terms representing thermal or instrumental noise, but for macroscopic systems and carefully designed experiments the stochastic forces are often negligible. An aim of theory is to describe solutions of the deterministic equations that are likely to be reached starting from typical initial conditions and to persist at long times. A unified description is developed, based on the linear instabilities of a homogeneous state, which leads naturally to a classification of patterns in terms of the characteristic wave vector q0 and frequency ω0 of the instability. Type Is systems (ω0=0, q0≠0) are stationary in time and periodic in space; type IIIo systems (ω0≠0, q0=0) are periodic in time and uniform in space; and type Io systems (ω0≠0, q0≠0) are periodic in both space and time. Near a continuous (or supercritical) instability, the dynamics may be accurately described via "amplitude equations," whose form is universal for each type of instability. The specifics of each system enter only through the nonuniversal coefficients. Far from the instability threshold a different universal description known as the "phase equation" may be derived, but it is restricted to slow distortions of an ideal pattern. For many systems appropriate starting equations are either not known or too complicated to analyze conveniently. It is thus useful to introduce phenomenological order-parameter models, which lead to the correct amplitude equations near threshold, and which may be solved analytically or numerically in the nonlinear regime away from the instability. The above theoretical methods are useful in analyzing "real pattern effects" such as the influence of external boundaries, or the formation and dynamics of defects in ideal structures. An important element in nonequilibrium systems is the appearance of deterministic chaos. A greal deal is known about systems with a small number of degrees of freedom displaying "temporal chaos," where the structure of the phase space can be analyzed in detail. For spatially extended systems with many degrees of freedom, on the other hand, one is dealing with spatiotemporal chaos and appropriate methods of analysis need to be developed. In addition to the general features of nonequilibrium pattern formation discussed above, detailed reviews of theoretical and experimental work on many specific systems are presented. These include Rayleigh-Benard convection in a pure fluid, convection in binary-fluid mixtures, electrohydrodynamic convection in nematic liquid crystals, Taylor-Couette flow between rotating cylinders, parametric surface waves, patterns in certain open flow systems, oscillatory chemical reactions, static and dynamic patterns in biological media, crystallization fronts, and patterns in nonlinear optics. A concluding section summarizes what has and has not been accomplished, and attempts to assess the prospects for the future.

/pdf/pattern-formation-outside-of-equilibrium-1601b9znum.pdf

Pattern formation outside of equilibrium

Flavonoids are nearly ubiquitous in plants and are recognized as the pigments responsible for the colors of leaves, especially in autumn. They are rich in seeds, citrus fruits, olive oil, tea, and red wine. They are low molecular weight compounds composed of a three-ring structure with various substitutions. This basic structure is shared by tocopherols (vitamin E). Flavonoids can be subdivided according to the presence of an oxy group at position 4, a double bond between carbon atoms 2 and 3, or a hydroxyl group in position 3 of the C (middle) ring. These characteristics appear to also be required for best activity, especially antioxidant and antiproliferative, in the systems studied. The particular hydroxylation pattern of the B ring of the flavonoles increases their activities, especially in inhibition of mast cell secretion. Certain plants and spices containing flavonoids have been used for thousands of years in traditional Eastern medicine. In spite of the voluminous literature available, however, Western medicine has not yet used flavonoids therapeutically, even though their safety record is exceptional. Suggestions are made where such possibilities may be worth pursuing.

The Effects of Plant Flavonoids on Mammalian Cells:Implications for Inflammation, Heart Disease, and Cancer

Dynamics and quenching of non-premixed edge-flames in oscillatory counterflows

We examine the behavior of a diffuse layer of metallic dust particles under the combined influence of gravity and magnetic fields Such a configuration has recently been proposed as a means of promoting passive removal of orbital space debris by artificially enhancing the drag on the debris, thereby decelerating it and hastening its reentry into the thermosphere We assume that the metallic dust particles become charged in the earth's ionosphere so that the particles in the layer can be treated collectively as a plasma continuum Using two- and three-dimensional magnetohydrodynamic simulations, we consider the long-time nonlinear evolution of several such ideal dusty plasma layers Simulations confirm that the well-known Rayleigh-Taylor instability that arises when a heavy fluid is placed on top of a lighter fluid is present in these systems We show that a quiescent, uniform layer is unstable to very small perturbations and rapidly breaks up Layer breakup is complete within 15 minutes after particle deposition, which is much too short a time to provide any meaningful reduction in debris velocity We consider a possible method for stabilizing the layer by imposing a tailored shear flow, a technique that has shown promise for stabilizing plasmas in magnetic fusion applications We discuss the long-time evolution of dusty plasma layers subjected to this shearing motion and show how layer stability is affected for a range of flow conditions We also highlight other practical aspects of layer initialization, orientation, and morphology and discuss how these properties impact layer stability The results of the full nonlinear numerical simulations are compared to results obtained using a linear theory

http://ieeexplore.ieee.org/iel7/6916485/6927938/06928102.pdf

Gravitational instability and shear stabilization in a dusty plasma layer

The properties of a front between two different phases in the presence of a smoothly inhomogeneous external field that takes its critical value at the crossing point is analyzed. Two generic scenarios are studied. In the first, the system admits a bistable solution and the external field governs the rate in which one phase invades the other. The second mechanism corresponds to a second order transition that, in the case of reactive systems, takes the form of a transcritical bifurcation at the crossing point. We solve for the front shape and its response to external white noise, showing that static properties and also some of the dynamics features cannot distinguish between the two scenarios. The only reliable indicator turns out to be the fluctuation statistics. These take a Gaussian form in the bifurcation case and a double-peak shape in a bistable system. The results of a recent analysis of the morphogenesis process in Drosophila embryos are reanalyzed and we show, in contrast with the interpretation suggested by Krotov et. al., that the plausible underlying dynamics is bistable and not bifurcational.

Fronts and fluctuations at a critical surface

In nonequilibrium surface growth processes, such as molecular beam epitaxy and chemical vapor deposition, kinetic roughening plays a significant role in determining surface morphology. The stochastic dynamics in the processes induce novel scaling in surface roughness with respect to growth time and system sizes. We present here a series of numerical simulation studies of simple theoretical models, such as ballistic deposition model and biased solid-on-solid model, to demonstrate the dynamical scaling and phase transitions in a class of surface growth problems in the context of the Kardar-Parisi-Zhang theory. Different dynamical processes, such as desorption and surface diffusion, are shown to have dramatic effects on the scaling and thus the surface structures.

Kinetic Roughening in Surface Growth

Comment on "Phase Transition in a Restricted Solid-on-Solid Surface-Growth Model in 2 + 1 Dimensions" In a recent Letter, Amar and Family generalized a restricted solid-on-solid (RSOS) nonequilibrium growth model in 2+1 dimensions to include temperature and reported finding a rough-to-rough phase transition at *c«0.62 where the surface width £ scales with the system size L as (InL). It was later shown that the transition is due to the vanishing of the coefficient X of the nonlinear term in the Kardar, Parisi, and Zhang (KPZ) equation of interface growth. In this Comment, we present further systematic simulation results which suggest that at some finite X, this model exhibits behavior very similar to that observed in a modified ballistic deposition model. Furthermore, we describe the scaling behavior in the low-temperature regime based on a calculation in the limit of tc^>\nL. We performed our simulations on the model of Ref. 1 and measured the effective roughness exponent, aefr =ln[^(Ii)/^(L2)]/ln(Z<i/L2). In Fig. 1, we plot aeff vs K from data for systems of size 10x10, 20x20, 50x50, and 100x100. The data are averaged over 20-40 ensembles. It shows that while at K = 0 . 3 , aeff increases with L to the strong-coupling value, it decreases at fc=0.5 as L increases, indicating an apparent change in asymptotic scaling. This behavior is very similar to that found in a modified ballistic deposition model and in other calculations, while in contrast with the conjecture that before K = 0 . 6 2 , the exponent would asymptotically approach the strong-coupling value. Recent arguments show that X<0 for K<0.62 while X>0 for K > 0.62. Since the sign of X is irrelevant, one should expect a similar situation at some K > 0.62. There is indeed evidence of this sort shown in Fig. 1 at about K : « 1 . 1 . While the numerical results' suggest that there is a true phase transition at some finite X value, the possibility of a slow crossover, a situation somewhat more desirable on theoretical grounds, is not ruled out. We emphasize here, however, the striking similarity among different growth models in which X is tuned in different ways. In the low-temperature regime, the picture of a rough surface emerging from the simulations is puzzling, because one would imagine that the growth probability e~ will favor island growth and the surface will flatten out as the temperature gets lower. To investigate what is going on in this regime, we performed exact calculations on small systems and numerical simulations on large ones. We found that for a fixed L, when K is very large, island growth is favored and the surface width § scales as %-~Le ~, given Le ~<^\. The sharp contrast to the equilibrium case, where £ is independent of L, should be noted. The onset for this scaling to occur appears to be at K~-lnL. Thus for small systems, we should expect to see the crossover to this kind of scaling at some not-so-large K\ This crossover has shown up in 0.6

David A. Kessler

Papers

Dynamics and quenching of non-premixed edge-flames in oscillatory counterflows

Gravitational instability and shear stabilization in a dusty plasma layer

Fronts and fluctuations at a critical surface

Kinetic Roughening in Surface Growth

Comment on "Phase transition in a restricted solid-on-solid surface-growth model in 2+1 dimensions"