Analysis of Specific Regions

The region downstream of the catalytic Cys also allows nitrilases and cyanide hydratases to be distinguished relatively successfully. The experimentally confirmed cyanide hydratases contain an Asn residue at position 3 downstream of the catalytic Cys [5, 6], whereas most of the characterized nitrilases carry a His at this position except for a few enzymes (from A. thaliana and Klebsiella ozaenae with an Asn at the corresponding site [3]). 

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When coupled to a microscope a Raman instrument with a high spatial resolution (approximately 5 tm) is then available which can produce spectra that are largely fluorescent-free. The Raman microscope exhibits a high signal-to-noise ratio and is ideal for the characterization of weak scattering samples and analysis of specific regions within a sample. 

Alternative Techniques for the Analysis of Defined Variants Once defined a putative variant to be tested in a population of patients, different techniques may be preferred, directly focused on the base(s) of interest. They are usually performed on genomic DNA without the need of a previous amplification or cloning of specific regions, which make them a very straight and convenient way of analyzing human DNA variation. These alternative... 

With the use of model systems and blends of polycaprolactone and phenoxy resin, it is shown that data obtained from the OH stretch overtone absorption in NIR is consistent with those from the OH stretch fundamental in the mid-IR region. The advantages of NIR analysis of specific interactions are illustrated with spectra obtained from thick films of blends of nylon 6 and the zinc salt of sulphonated PS. 9 refs. 

The underlying principle of this method, namely base-specific cleavage, is now used more widely for the sequence analysis of target regions. Further applications... 

An important step in the development of techniques allowing such a molecular analysis of large regions in mammalian genomes has been the identification of restriction enzymes cutting rarely in mammalian DNA, and therefore able to cleave the mammalian genome into specific fragments of hundreds to thousands of kilo-base pairs. 

Analysis of Surface Elemental Composition. A very important class of surface analysis methods derives from the desire to understand what elements reside at the surface or in the near-surface region of a material. The most common techniques used for deterrnination of elemental composition are the electron spectroscopies in which electrons or x-rays are used to stimulate either electron or x-ray emission from the atoms in the surface (or near-surface region) of the sample. These electrons or x-rays are emitted with energies characteristic of the energy levels of the atoms from which they came, and therefore, contain elemental information about the surface. Only the most important electron spectroscopies will be discussed here, although an array of techniques based on either the excitation of surfaces with or the collection of electrons from the surface have been developed for the elucidation of specific information about surfaces and interfaces. 

The uniqueness and desirability of EELS is realized when it is combined with the power of a TEM or STEM to form an Analytical Electron Microscope (AEM). This combination allows the analyst to perform spatially resolved nondestructive analysis with high-resolution imaging (< 3 A). Thus, not oiJy can the analyst observe the microstructure of interest (see the TEM article) but, by virtue of the focusing ability of the incident beam in the electron microscope, he or she can simultaneously analyze a specific region of interest. Lateral spatial resolutions of regions as small as 10 A in diameter are achievable with appropriate specimens and probe-forming optics in the electron microscope. 

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