Dissection

Finally, by volumetric imaging Three-dimensional information was obtained by stacking reflection tomograms from multiple planes. Using this stacking technique, cubic voxels were obtained and could be numerically dissected in any plane. Although there are several attractive features related to this technique, there are also several questions which need to be addressed before it can be used for industrial applications. For example, the applied sound field must be further characterized. 

Hansma H G, Vesenka J, Siegerist C, Kelderman G, Morrett H, Sinsheimer R L, Bustamante C, Elings V and Hansma P K 1992 Reproducible imaging and dissection of plasmid DNA under liquid with the atomic force microscope Science 256 1180... 

It is now understood tliat inclusion of nearest and second-neighbour interactions is adequate for describing tunnelling interactions in many bridged systems [31, 32]. Moreover, tunnelling interactions have been dissected for various... 

This basic LFER approach has later been extended to the more general concept of fragmentation. Molecules are dissected into substructures and each substructure is seen to contribute a constant inaement to the free-energy based property. The promise of strict linearity does not hold true in most cases, so corrections have to be applied in the majority of methods based on a fragmentation approach. Correction terms are often related to long range interactions such as resonance or steric effects. 

A number of other software packages are available to predict NMR spectra. The use of large NMR spectral databases is the most popular approach it utilizes assigned chemical structures. In an advanced approach, parameters such as solvent information can be used to refine the accuracy of the prediction. A typical application works with tables of experimental chemical shifts from experimental NMR spectra. Each shift value is assigned to a specific structural fragment. The query structure is dissected into fragments that are compared with the fragments in the database. For each coincidence, the experimental chemical shift from the database is used to compose the final set of chemical shifts for the... 

The retrosynthetic analysis is performed in two steps in a first step, SYNGEN dissects the skeleton to find all fully convergent bondsets which utili2e starting material skeletons found in two successive levels of cuts. A bondset is a set of skeletal bonds that is cut during the retrosynthetic analysis or formed in any given synthesis. 

Substructure searches provide another method of searching for available starting materials. They arc used primarily for planning the synthesis of combinatorial libraries. After the target compound has been dissected into a set of suitable precursors, substructure searches can provide for each of them a series of representatives of a certain class of compounds, Siibsti ucturc searches enable the user to specify attributes such as open sites or atom lists at certain positions of the structure. Figure 10.3-38 shows the possible specification elements for the query in a substructure search. 

The process of target identification analyzes a complex disease process by dissecting it into its fundamental components. This makes it possible to identify the one that is most integral to the manifestation of the disease. Target identification aims to understand the biological processes related to a disease, and to identify its mechanism and the structure of individual elements of the disease. Commonly these individual elements are receptors, enzymes, etc., which become the target of new drugs. 

The calculated result as we have found it by this dissection of the G2 method agrees with the final result of the G2 script... 

Data for carcass composition corresponding to protein and lipid are percent-dissected skeletal muscle and adipose, respectively. 

Diseases. Liquid crystals have been impHcated in a number of disease conditions in the human body. A complex cholesterol—phosphoHpid—Hpoprotein Hquid crystal phase has been identified in the initiation and maintenance of atheromatous deposits on the aortic intima in dissected human and rabbit arteries (40). The paracrystalHne nature of this precursor to plaque buildup with the resultant loss of arterial elasticity... 

The generalized transport equation, equation 17, can be dissected into terms describing bulk flow (term 2), turbulent diffusion (term 3) and other processes, eg, sources or chemical reactions (term 4), each having an impact on the time evolution of the transported property. In many systems, such as urban smog, the processes have very different time scales and can be viewed as being relatively independent over a short time period, allowing the equation to be "spht" into separate operators. This greatly shortens solution times (74). The solution sequence is... 

Y"et, corrosion engineering and science is no longer an empirical art dissecting a large corrosion problem into its basic mechanisms allows the use of quite sophisticated electrochemical techniques to accomplish satisfactory results. On that positive side, there is real satisfaction and economic gain in designing a component that can resist punishing seiwice conditions under which other parts fail. In some cases, we cannot completely prevent corrosion, but we can try to avoid obsolescence or the component due to corrosion. 

Figure A1.27 shows the unusual silver-strontium phase diagram. It has four inter-metallic compounds. Note that it is just five simple phase diagrams, like the Pb-Sn diagram, stuck together. The first is the Ag-SrAgj diagram, the second is the SrAgj-Sr.Agj diagram, and so on. Each has a eutectic. You can always dissect complicated diagrams in this way.

Dissected Number Mixture Combustible Components Species % Inert Components C02,% N2,% Total, % Ratio of Inert to Combustible Lower Limit % Upper Limit % Source of Limit... 

Let us now examine this molecule and dissect it into its structural components to see if we can understand how these are put together. We will reduce this rather complex, and at first sight bewildering, structure to its simplest representation as a series of motifs. This will help us to understand the stmcture and see its relationships to other structures. 

Transition-state stabilization in subtilisin is dissected by protein engineering... 

Carter, P, Wells, J.A. Dissecting the catalytic triad of a serine protease. Nature 332 564-568, 1988. 

A structural anomaly in subtilisin has functional consequences Transition-state stabilization in subtilisin is dissected by protein engineering Catalysis occurs without a catalytic triad Substrate molecules provide catalytic groups in substrate-assisted catalysis Conclusion Selected readings... 

MO calculations can provide the minimum-energy structure, total energy, and overall electron density of a given molecule. However, this information is in the form of the sum of the individual MOs and cannot be easily dissected into contributions by specific atoms or groups. How can the properties described by the MOs be related to our concept of molecules as a colleetion of atoms or functional groups held together by chemical bonds ... 

Since AG and AG are combinations of enthalpy and entropy terms, a linear free-energy relationship between two reaction series can result from one of three circumstances (1) AH is constant and the AS terms are proportional for the series, (2) AS is constant and the AH terms are proportional, or (3) AH and AS are linearly related. Dissection of the free-energy changes into enthalpy and entropy components has often shown the third case to be true. °... 

In general, the dissection of substituertt effects need not be limited to resonance and polar components, vdiich are of special prominence in reactions of aromatic compounds.. ny type of substituent interaction with a reaction center could be characterized by a substituent constant characteristic of the particular type of interaction and a reaction parameter indicating the sensitivity of the reaction series to that particular type of interactioa For example, it has been suggested that electronegativity and polarizability can be treated as substituent effects separate from polar and resonance effects. This gives rise to the equation... 

Studies of the stereochemical course of rmcleophilic substitution reactions are a powerful tool for investigation of the mechanisms of these reactions. Bimolecular direct displacement reactions by the limSj.j2 meohanism are expected to result in 100% inversion of configuration. The stereochemical outcome of the lirnSj l ionization mechanism is less predictable because it depends on whether reaction occurs via one of the ion-pair intermediates or through a completely dissociated ion. Borderline mechanisms may also show variable stereochemistry, depending upon the lifetime of the intermediates and the extent of internal return. It is important to dissect the overall stereochemical outcome into the various steps of such reactions. 

By using the product ratio, the overall rate can be dissected into the individual rates for formation of 2 and 3. These rates are found to be substituent/dependent for formation of 2 (p = +1.4) but substituent independent for formation of 3 (p = —0.1 0.1). The reactions are both second-order, first-order in base and first-order in substrate. 

The effect of substituents on electrophilic substitution can be placed on a quantitative basis by use ofpartial rate factors. The reactivity of each position in a substituted aromatic compound can be compared with that of benzene by measuring the overall rate, relative to benzene, and dissecting the total rate by dividing it among the ortho, meta, and para... 

Fig. 4. Application of fibrin sealant (arrow points to spray head for applying two-component adhesives) at the time of mastectomy and axillary dissection to reduce seroma formation.

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