Disordered systems behavior

Although genetic influences on the dynamics of drug response have been studied in a wide range of disorders, most of the studies have been carried out in only the past few years. Disorders and behaviors studied include Alzheimer s disease, schizophrenia, depression, suicide, anxiety, obsessive-compulsive disorder (OCD), substance abuse, smoking, and alcoholism. Across these disorders, however, there has been a focus on only a handful of neuroeffector systems. These include apolipoprotein and the cholinergic system (in Alzhei-... 

While many researchers believe that the above mentioned three ingredients for rl behavior to appear are more or less independent, we have argued since long [6] that the primary cause of RL behavior is the lattice disorder, which is at the origin of the occurrence of polar nanodomains and their fluctuations within the highly polarizable lattice. In order to describe disordered systems and to explore their basic thermodynamic behavior simple spin models are frequently used. The model Hamiltonian... 

This chapter concentrates on the results of DS study of the structure, dynamics, and macroscopic behavior of complex materials. First, we present an introduction to the basic concepts of dielectric polarization in static and time-dependent fields, before the dielectric spectroscopy technique itself is reviewed for both frequency and time domains. This part has three sections, namely, broadband dielectric spectroscopy, time-domain dielectric spectroscopy, and a section where different aspects of data treatment and fitting routines are discussed in detail. Then, some examples of dielectric responses observed in various disordered materials are presented. Finally, we will consider the experimental evidence of non-Debye dielectric responses in several complex disordered systems such as microemulsions, porous glasses, porous silicon, H-bonding liquids, aqueous solutions of polymers, and composite materials. 

In 1991, Bonny and Leuenberger [40] explained the changes in dissolution kinetics of a matrix controlled-release system over the whole range of drug loadings on the basis of percolation theory. For this purpose, the tablet was considered a disordered system whose particles are distributed at random. These authors derived a model for the estimation of the drug percolation thresholds from the diffusion behavior. 

The Effective Medium Approximation (EMA), based in some assumptions, allows us to employ linear regressions as an approximation of the behavior of a disordered system outside the critical range. Based on EMA theory, two linear regressions have been performed as an approximation for estimating the percolation threshold as the point of intersection between both regression lines (see Figures 43 15). The values of the excipient percolation thresholds estimated for all the batches studied, based on the behavior of the kinetic parameters, ranged from 25.99 to 26.77%. 

The variation of 5(7) near the N-I phase transition will be measured in this experiment and will be compared with the behavior predicted by Landau theory, " " which is a variant of the mean-field theory first introduced for magnetic order-disorder systems. In this theory, local variations in the environment of each molecule are ignored and interactions with neighbors are represented by an average. This type of theory for order-disorder phase transitions is a very useful approximate treatment that retains the essential features of the transition behavior. Its simplicity arises from the suppression of many complex details that make the statistical mechanical solution of 3-D order-disorder problems impossible to solve exactly. 

Pyrolysis of a perylene-tetracarboxylic dianhydride monomer above 520 C resulted in vapor-phase condensation of poly-peri-naphthalene (PPN), a representative one-dimensional graphite polymer. PPN was obtained as fine whiskers with rectangular cross sections and exhibited electrical conduction behaviors characteristic of low-dimensional disordered systems. At HTT s above 2800 C,... 

Fractals can be considered as disordered systems with a non-integral dimension, called the fractal dimension. An important property of fractal objects is that they are self-similar, independent of scale. This means that if part of them is cutout, and then this part is magnified, the resulting object will look exactly the same as the original one. The other distinct property of a fractal is the power law or scaling behavior, where the property and variable of a system are related in the following manner ... 

The orbital-free simulations based on approximations to EHK[p are, however, attracting increasing interest because of their potential usefulness in studies of solids, liquids, and other materials where the simulations are aimed at describing collective behavior of large disordered systems and relative energies of different bound states not the absolute value of cohesion energy are the primary objects of interest (for representative applications see Refs. 29 42. For a comprehensive review, see Ref. 26. For more recent developments, see Ref. 27. 

Complete deficiency of HGPRT results in gout-related arthritis, dramatic malfunction of the nervous system, behavioral disorders, learning disability, and hostile or aggressive behavior, often self directed. In the most extreme cases, patients nibble at their fingertips or, if restrained, their lips, causing severe self-mutilation. 

In order to illustrate the scope and range of high pressure NMR experiments, the next part of the article discusses our recent results on relaxation and transport behavior of compressed supercritical water. The article finishes with a brief account of application of high pressure NMR to studies of the dynamic structure of various disordered systems. 

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