Computer software fragment

Fragment constant The partition coefficient is expressed as the sum of its component fragments log P=([jj an-fn where (a) is the number of fragment (f) of type (n) in the molecule Adjustment for steric effects, bond type and different interactions gives a complex calculation usually accomplished with computer software... 

The scope of the use of mass spectrometry in the protein analysis has grown enormously in the past few decades. MS has become an important analytical tool in biological and biochemical research. Its speed, accuracy and sensitivity are unmatched by conventional analytical techniques. The variety of ionization methods permits the analysis of peptide or protein molecules from below 500 Da to as big as 300 Da (Biemann 1990 Lahm and Langen 2000). Basically, a mass spectrometer is an instrument that produces ions and separates them in the gas phase according to their mass-to-charge ratio (m/z). The basic principle of operation is to introduce sample to volatilization and ionization source, and then the molecular fragments from the ionization of the sample are detected by various kinds of detector and the data are analyzed with computer software. 

In metabolism, more specifically newborn screening for amino acids and acyl-carnitines, we use two other types of MS/MS analyses the precursor and neutral loss scans. In both types of scan, the question is asked where did I come from In other words, a fragment of a molecule is detected that is unique or common to a particular molecule or family of structurally similar molecules. Because the instruments are linked in space rather than time, when a particular product is detected in the second mass spectrometer (MS2), the computer software knows what mass was being scanned in the first mass spectrometer (MSI). The difference between a precursor ion and neutral loss scan is the nature of the product. With a precursor ion scan, that product of interest is also an ion and it can be detected. With a neutral loss... 

The structure of the initial compound can be reconstructed from the ion fragments such as in a puzzle. The level of difficulty increases as the mass of the compound increases because successive fragmentation reactions of the ions are complex. The task can be simplified if several spectra are recorded under different conditions and if the appropriate computer software is available. 

Scientific illustrations are a form of art required for textbooks, museum exhibits, Web sites, and publications of scientific research. These figures often show what photographs cannot— the reconstruction of an object from fragments, comparisons among objects, or the demonstration of a process or idea. Scientific illustrators use everything from paper and pencil to computer software to provide this vital link in the scientific process. 

Kraft Dubnoff, Job content, fragmentation and control in computer software work ... 

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