Existing techniques

Analysis of Surface Molecular Composition. Information about the molecular composition of the surface or interface may also be of interest. A variety of methods for elucidating the nature of the molecules that exist on a surface or within an interface exist. Techniques based on vibrational spectroscopy of molecules are the most common and include the electron-based method of high resolution electron energy loss spectroscopy (hreels), and the optical methods of ftir and Raman spectroscopy. These tools are tremendously powerful methods of analysis because not only does a molecule possess vibrational modes which are signatures of that molecule, but the energies of molecular vibrations are extremely sensitive to the chemical environment in which a molecule is found. Thus, these methods direcdy provide information about the chemistry of the surface or interface through the vibrations of molecules contained on the surface or within the interface. 

All existing techniques of EEP detection may be divided into several groups spectral, calorimetric, chemical titration, electrical methods, and also a method of sensor detection. 

Not all of the classical extraction processes are suitable for ultrasonic enhancement. For example, among the existing techniques used to obtain bio-active extracts from plant material (direct distillation, water steam distillation, organic solvent extraction, maceration, cold/hot fat extraction, etc.) [195] the water steam distillation is not amenable to ultrasonic enhancement. 

CE is also potentially a useful alternative analytical tool for monitoring of chemicals (dyes, flame retardants and lubricants) involved in various steps of the textile fibre manufacturing process. In this area, CE compares favourably with existing techniques. CZE-MSn was used for the analysis of sulfonated azo dyes [942]. A variety of fluorescent analytes including thiazole orange dyes have been characterised by CE-FLNS [943]. 

A fundamental goal of research in the biological sciences is to understand protein structure. In theory, protein sequence information can be inferred from the fast growing volume of DNA sequence data [1] but predicting the three-dimensional structure of a protein from its sequence remains an open and important problem [2 1]. Part of the difficulty in solving this problem is due to the fact that many of the existing techniques rely on our knowledge of previously determined structures which, compared to sequence data, is relatively limited. 

The use of statistical tests to characterize model performance has increased markedly within the last few years as demonstrated by the references cited above many other examples are in the literature. The current time is appropriate for integration of existing techniques into a unified framework of guidelines, procedures and quantitative measures for model testing and validation. 

After determining the relevant physical properties (i.e., particle size, solids particle density and bulk density), the next step is to evaluate some of the existing techniques of powder classification. 

Certain difficulties remain, however, with this approach. First, such an important feature as a secondary structure did not find its place in this theory. Second, the techniques of sequence design ensuring exact reproduction of the given conformation are well developed only for lattice models of polymers. The existing techniques for continuum models are complex, intricate, and inefficient. Yet another aspect of the problem is the necessity of reaching in some cases beyond the mean field approximation. The first steps in this direction were made in paper [84], where an analog of the Ginzburg number for the theory of heteropolymers was established. 

Prior to the introduction of ion-selective electrode techniques, in situ monitoring of free copper (II) in seawater was not possible due to the practical limitations of existing techniques (e.g., ligand competition and bacterial reactions). Ex situ analysis of free copper (II) is prone to experimental error, as the removal of seawater from the ocean can lead to speciation of copper (II). Potentially, a copper (II) ion electrode is capable of rapid in situ monitoring of environmental free copper (II). Unfortunately, copper (II) has not been used widely for the analysis of seawater due to chloride interference that is alleged to render the copper nonfunctional in this matrix [288]. 

At present, the STM has been demonstrated to yield spectroscopic information regarding the spatial, vibrational, and electronic structure of surfaces. In all of these areas, the STM is complementary to other existing techniques. Also, and in many potential applications, STM possesses unique features and capabilities. These capabilities are discussed in the section below. 

No attempt is made to review the literature — references are only made to existing techniques as and when they impinge on the central ideas of this exposition. Occasionally we are critical of some of the established schemes this is not, of course, to belittle the importance of the ideas of the pioneers in this field but rather to question the continued uncritical use of these ideas. 

Any new analytical technique must be compared to existing techniques in order to determine its usefulness. IC has several characteristics which cause it to be the method of choice for several types of analyses. Some of the unique analytical capabilities of IC are ... 

Newer techniques are being developed and modifications of existing techniques continue. 

Most proteins must be folded into a specific three-dimensional conformation to express their specificity and activities, which comphcates the DSP [212]. Researchers in the area of RME of proteins/enzymes have reafized this and directed more efforts in developing novel and imaginative techniques in RME as well as coupling the existing techniques such as chromatography, electrophoresis, and membrane extractions with RME. Such promising techniques developed in the recent past have been discussed in this section. Apart from these techniques, use of novel surfactants in the RME and surfactant based separation processes (e.g., cloud-point extraction) are also considered. 

We have determined, however, that although existing techniques for the blending of aggregates can produce mixes with low... 

The existing techniques used to screen conventional chemicals, however, may not be adequate to support the discovery of new biopesticides, particularly biochemical pesticides. Non-traditional approaches for new compound discovery may be needed. The potential for the discovery of new naturally occurring... 

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