Three-dimensional Life

in a series of papers, ([bayes87a], [bayes87b], [bayes88], [bayesQO], and [bayesQl]) has searched for three-dimensional analogs of Conway s Life-rule that are worthy of the name [dewd87], 

The hexahedral tessellation presents more of a problem because of its nonorthogonality. Bayes [bayes87b] suggests two update schemes, both based on situating the sites on a cubic lattice (1) update according to 

Although, for either lattice, the iterative application of the update rules themselves is straightforward, the visualization of the time evolution of patterns is complicated by the fact that not all sites can be seen at one time. 

Before we summarize Bayes results, we should discuss briefly what the behavior of a Life-like rule worthy of the name ought to look like, or what we can expect it to look like. While the original two-dimensional Life-game was introduced in the last section formally as an outer-totalistic code OT224 rule, it is much more convenient to define it in terms of the sizes of two environments a survival environment E, and 

After exhaustive simulations, Bayes has found only three rules on the cubic lattice ( = (4555), = (5766), = (5655)) and two rules on the hexahedral tessellation ( = (3333) and = (4633)) tliat can arguably be called worthy of the name ([bayes87a], [bayesQO] and [bayesQl]). We follow Bayes nomenclature in calling these rules, respectively, Life-4555, Life-5766, Life-5655), Life-3333 and Life-4633. 

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Next, introduce two primitive concepts [bayes87a]. (1) An expansion, (C), of a Conway object C = (xi,yi,z = 0), which is a three-dimensional pattern, P, formed by copying all live cells of that object onto an adjacent plane, so that xi,yi,z = 0), xi,yy,z = 1). (2) A projection of a three-dimensional Life object into two dimensions, which exists if and only if (i) all of its live sites lie in two adjacent planes (say 2=0 and 2 = 1), and (ii) all pairs of sites, (xi,yi,0) and xi,yi, 1) are either both live or both dead. 

A three-dimensional analog of a Conway object is then defined to be an expansion sucli that, when subjected to the appropriate three-dimensional Life-rule, yields after each and every generation a projection that is identical to the original Conway object for the same iteration step under Conway s original two-dimensional... 

A first example of application of microtomography is taken from life sciences. Here X-ray microscopy and microtomography allows to reconstruct the internal three-dimensional microstructure without any preparation and sometimes even of living objects. Fig. la shows an X-ray transmission microscopical image of bone (femoral head). Several reconstructed cross-sections are shown in Fig.lb. Fig.lc shows the three-dimensional reconstruction of this bone. 

The balance of this chapter will be devoted to several classic and representative enzyme mechanisms. These particular cases are well understood, because the three-dimensional structures of the enzymes and the bound substrates are known at atomic resolution, and because great efforts have been devoted to kinetic and mechanistic studies. They are important because they represent reaction types that appear again and again in living systems, and because they demonstrate many of the catalytic principles cited above. Enzymes are the catalytic machines that sustain life, and what follows is an intimate look at the inner workings of the machinery. 

About three years after Wachtershauser s first publication appeared, an article by Christian de Duve and Stanley Miller was published in the Proceedings of the National Academy of Sciences under the title Two-Dimensional Life the title alluded to the theory of reactions at positively charged pyrite surfaces (de Duve and Miller, 1991). Their criticisms of the chemoautotrophic theory were directed particularly towards certain kinetic and thermodynamic aspects, but also to theoretical statements for which no experimental support was available. 

Proteins start out life as a bunch of amino acids linked together in a head-to-tail fashion—the primary sequence. The one-dimensional information contained in the primary amino acid sequence of cellular proteins is enough to guide a protein into its three-dimensional structure, to determine its specificity for interaction with other molecules, to determine its ability to function as an enzyme, and to set its stability and lifetime. 

In this paper we examined quantum aspects of special classical configurations of two-electron atoms. In the doubly excited regime, we found quantum states of helium that are localized along ID periodic orbits of the classical system. A comparison of the decay rates of such states obtained in one, two and three dimensional ab initio calculations allows us to conclude that the dimension of the accessible configuration space does matter for the quantitative description of the autoionization process of doubly excited Rydberg states of helium. Whilst ID models can lead to dramatically false predictions for the decay rates, the planar model allows for a quantitatively reliable reproduction of the exact life times. 

Biosensors fabricated on the Nafion and polyion-modified palladium strips are reported by C.-J. Yuan [193], They found that Nafion membrane is capable of eliminating the electrochemical interferences of oxidative species (ascorbic acid and uric acid) on the enzyme electrode. Furthermore, it can restricting the oxidized anionic interferent to adhere on its surface, thereby the fouling of the electrode was avoided. Notably, the stability of the proposed PVA-SbQ/GOD planar electrode is superior to the most commercially available membrane-covered electrodes which have a use life of about ten days only. Compared to the conventional three-dimensional electrodes the proposed planar electrode exhibits a similar... 

What are the facts of life One of the most striking is that all known living systems involve the same types of polymers, i.e., three varieties of homochiral biopolymers. That is, each variety is composed of unique molecular building blocks having the same three-dimensional handedness. Thus, with rare exceptions, the proteins found in cells are composed exclusively of the 1-enantiomers of 19 optically active amino acids (Fig. 11.1). Similarly, only D-ribose and 2-deoxy-D-ribose sugars are found in the nucleic acid polymers that make up the RNAs and DNAs, which are essential for protein synthesis in the cell and for the transmission of genetic information from one generation to the next. 

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