Random disorder

Oxcarbazepine is a keto derivative of carbamazepine but offers several advantages over carbamazepine. Oxcarbazepine does not require blood cell count, hepatic, or serum drug level monitoring. It causes less cytochrome P450 enzyme induction than does carbamazepine (but may decrease effectiveness of oral contraceptives containing ethinyl estradiol and levonorgestrel). As opposed to carbamazepine, oxcarbazepine does not induce its own metabolism. These properties, combined with its similarity to carbamazepine, led many clinicians to use this medication for the treatment of bipolar disorder. Randomized controlled trials suggested efficacy in the treatment of acute mania compared with lithium and haloperidol, but these trials were quite small and did not include a placebo control (Emrich 1990). 

Figure 10.14 Illustration of carbon fibers, side and end views (A) ordered onion fiber (B) disordered random fiber.

Leinonen E, Lepola U, Koponen H, Turtonen J, Wade A, Lehto H (2000) Citalopram controls phobic symptoms in patients with panic disorder randomized controlled trial. J Psychiatry Neurosci 25 24—32... 

Baldwin D, Bobes J, Stein DJ, Scharwachter I, Faure M (1999) Paroxetine in social phobia/social anxiety disorder. Randomized, double-blind, placebo-controlled study. Paroxetine Study Group. Br J Psychiatry 175 120-126... 

Of 65 men (mean age 52 years) with post-traumatic stress disorder randomized to risperidone (n = 33) or placebo (n = 32) in a 4-month double-blind study supported by the Janssen Research Foundation, 22 and 26 patients respectively completed the study (52). There were no significant differences in weight. 

The obvious difficulty of finding an optimal theoretical approach for the zeolites is precisely due to its intermediary character the active site, which is local par excellence, is embedded in a periodic lattice, and it is strongly influenced by the whole periodic lattice. Moreover, in a strict sense, one cannot speak about a tme periodic system, since the A1-substitutions and the active sites are usually distributed in a disordered, random manner. Therefore, in some sense, we can say that none ofthe standard approaches, neither the local... 

One way to remember the relation between entropy and disorder is to consider a handful of chopsticks. Dropped on the floor, they are arranged randomly (a state of high entropy). Placed end-to-end in a straight line, they are arranged intentionally (a state of low entropy). The more disordered, random arrangement is favored and easier to achieve energetically. 

The pyranose ring conformations that are important in polysaccharides are the two chair conformations, designated and Q (Fig. 10) to indicate the disposition of atoms above and below the plane of the ring (in older notation the same conformations were denoted by Cl and 1C, respectively). Boat conformations probably have some existence in low proportions in disordered (random coil) polysaccharide chains. 

Since entropy (S) is a measure of disorder (randomness), it is the energy that is unavailable for useful work. Entropy values of denatured molecules are high relative to those of native structures (as in protein denaturation). In a living system, entropy is kept at a minimum by utilization of free energy (G) from outside and by increase in entropy of the surroundings. 

Connor KM, Sutherland SM, Tupler LA et al. Fluoxetine in post-traumatic stress disorder. Randomized, double blind study. Br j Psychiatry 1999 1 75 1 7-22. 

We have seen in this subsection once again that one of the determining factors in making a system successful in the information processing framework with disordered (random) connections is the correct balance of system size, connectivity degrees and firing thresholds. Other factors like learning rates and output redundancy may play equally important roles. 

This is assuming that the thf is ordered. Sometimes, when the oxygen is disordered randomly over the five possible positions, it can be best to refine the tetrahydrofuran as a five-membered all-carbon ring. See Section 7.8.4 for an example. 

It is surprising, in view of the many structures that are derived from either the hexagonal (ABAB) or cubic (ABCABC) closest packing (see Section 5.4.1), that so few complex arrangements occur. Cobalt is one metal that shows this behaviour. Below about 435 C the structure is a disordered random stacking of A, B and C planes of metal atoms. It can be transformed into the A3 structure by careful annealing at lower temperatures, and this transforms to the Al structure above 435 °C. 

Statistical fractals are generated by disordered (random) processes. An element of disorder is typical of most real physical phenomena and objects. The fact that disorder, i.e., the absence of any spatial correlation, is a sufficient condition for the formation of fractals was first noted by Mandelbrot [1]. A typical example of this type of fractal is the random-walk path. However, real physical systems are often inadequately described by purely statistical models. Among other reasons, this is due to the effect of excluded volume. The essence of this effect lies in the geometric restriction that forbids two different elements of a system to occupy the same volume in space. This restriction is to be taken into account in the corresponding modelling [10, 11]. The best-known examples of this type of models are self-avoiding random walk, lattice animals and statistical percolation. 

---