Descriptive centers

At present, quite a number of works are using one of three methods vector description, description centers, or topological indexes. The vector description is the simplest one it is usually used when there is a series of N similar molecules, e.g., having the same skeleton with different substituents. In these cases, each (k) molecule of the series can be presented by a vector C, ... 

GenBank [32] is a text-numeric database of genetic sequences with more than 28 billion bases in 22 million sequences (January, 2003) from genetic research. The collection of all publidy available sequences is annotated with information such as sequence description, source organism, sequence length, or references. The database, estabhshed in 1967, is updated daily and produced by the National Center for Biotechnology Information (USA). 

The conformation-dependent chirality code constitutes a more general description of molecular chirality, which is formally comparable with the CICC [43], The main difference is that chiral carbon atoms arc now not explicitly considered, and combinations of any four atoms are now used, independently of the existence or nonexistence of chiial centers, and of their belonging or not belonging to ligands of chiral centers. 

One of the most widely used - and successful representations of the constitution, the topology, of a molecule is the HOSE code (Hierarchical Ordered description of the Substructure Environment) [9]. It is an atom-centered code taking into account... 

Nucleation is assumed to begin simultaneously from centers positioned at random throughout the liquid. This is more descriptive of heterogeneous nucleation by foreign bodies introduced at a given moment than of random nucleation. We shall dispense with the requirement of simultaneity below. 

J. M. O Coimor, T. C. Ginn, and G. V. Pase, The Evaluation and Description of a Power Plant Condenser Tube Simulator, Report No. 8-0248-956, New York University Medical Center, New York, 1977. 

Bond lengths and infrared spectra support the multiple-bond character of the M—CO bonds. Coordination of a CO molecule to a metal center can change the C—O bond order. According to the description of ( - and TT-bonding given herein, increased ( -bonding between a metal and CO results in a... 

Although Lewis structures of this type are not entirely adequate descriptions of the structure of the excited states, they do correspond to the MO picture by indicating distortion of chaige and the presence of polar or radical-like centers. The excited states are much more reactive than the corresponding ground-state molecules. In addition to the increased energy content, this high reactivity is associated with the presence of half-filled orbitals. The two SOMO orbitals in the excited states have enhanced radical, cationic, or anionic character. 

The following shipping paper is only illustrative since it may vary in format. However, all descriptions will be basically Ihe same. You should look for this type of eniry lo determine the shipping name of the haiardous material, its classification, its 10 number (10 No.), and a reportable quantity notation (RO or RO-number) for use in reporting spill incidents to the National Response Center. With very few exceptions, shipping papers identifying haiardous materials are required when they are being transported ... 

It should be emphasized that the correct description of the peculiar effect brought about by the presence of two or more sp -nitrogen centers within a molecule can be reproduced reliably only by high level ah initio calculations accounting for electron correlation. This conclusion is well justified by the examples of benzotriazole, 3-amino-l,2,4-triazole, and tetrazole, as described in Sections II,B,3 II,B,4 and II,B,5, respectively. 

Note carefully the difference between enantiomers and diastereomers. Enantiomers have opposite configurations at all chirality centers, whereas diastereomers have opposite configurations at some (one or more) chirality centers but the same configuration at others. A full description of the four stereoisomers of threonine is given in Table 9.2. Of the four, only the 2S,3R isomer, [o]D= -28.3, occurs naturally in plants and animals and is an essential human nutrient. This result is typical most biological molecules are chiral, and usually only one stereoisomer is found in nature. 

Conjugated enones are more stable than nonconjugated enones for the same reason that conjugated dienes are more stable than nonconjugated dienes (Section 14.1). Interaction between the tt electrons of the C=C bond and the tt electrons of the C=0 group leads to a molecular orbital description for a conjugated enone that shows an interaction of the tt electrons over all four atomic centers (Figure 23.3). 

According to the quantum mechanical description of the 1 s orbital of the hydrogen atom, what relation exists between the surface of a sphere centered about the nucleus and the location of an electron ... 

The quantum mechanical description of the Is orbital is similar in many respects to a description of the holes in a much used dartboard. For example, the density of dart holes is constant anywhere on a circle centered about the bullseye, and the "density of dartholes reaches zero only at a very long distance from the bullseye (effectively, at infinity). What are the corresponding properties of a If orbital ... 

The reflection 7 of x-rays by a crystal (x-ray diffraction) results fundamentally from the unmodified scattering of x-rays by the atoms or ions in the different planes of the crystal. For many purposes, it suffices to regard the atoms or ions as the scattering centers, but a complete description of the process requires that the electrons be considered. 

The interest, economics and changing tastes together indicated the most important phenomenon, which pushed cocktails into center stage—the acceptance by women of cocktail drinking as a social form, and a new equality of enjoyment in going out. The cocktail scene, as opposed to the bar scene, was sexually comfortable and independent—mutually neutral territory where a group of any description could spend a few hours or an evening over a few conversation-piece drinks or a few favorites. 

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