Molecular fingerprinting methods

MOLPRINT 2D A molecular fingerprint method for similarity searching [63]... 

Valence band spectra provide information about the electronic and chemical structure of the system, since many of the valence electrons participate directly in chemical bonding. One way to evaluate experimental UPS spectra is by using a fingerprint method, i.e., a comparison with known standards. Another important approach is to utilize comparison with the results of appropriate model quantum-chemical calculations 4. The combination with quantum-chcmica) calculations allow for an assignment of the different features in the electronic structure in terms of atomic or molecular orbitals or in terms of band structure. The experimental valence band spectra in some of the examples included in this chapter arc inteqneted with the help of quantum-chemical calculations. A brief outline and some basic considerations on theoretical approaches are outlined in the next section. 

Since LEAP1 was built based on Pipeline Pilot technology, multiple molecular fingerprints and similarity methods can be applied at disposal, which currently include MDL Public Keys and different levels of FCFPs and ECFPs (18). 

Fig. 4. A solution of nucleotide triphosphate is incubated in the presence of QP replicase for just long enough to assure the manifold replication of any templates that may contaminate the enzyme. The incubation is interrupted before even one template has time to arise de novo. The solution is then divided up into portions and the incubation is continued, this time long enough to allow products to arise de novo and to multiply. The RNA formed in each portion is analyzed by the fingerprint method various different reaction products are found. Sometimes the growth curve displays the appearance of a new mutant. Although the incubation time of template-instructed synthesis is determined unambiguously (because of the superposition of many individual processes) the synthesis de novo shows a scatter of induction times. This indicates that the initiation step is a unique molecular process which is then rapidly amplified. ...

In this chapter, we will review near-field optical methods and their applications to problems in biology and materials science. Near-field techniques provide nanometer spatial resolution by overcoming the Abbe diffraction Hmit, and can be used to investigate many types of sample in situ. Here, emphasis is placed on near-field methods that provide vibrational information (i.e., molecular fingerprints ) of the analytes. Finally, the current challenges faced by these methods and their potential in nanoscale chemical analysis in the near future are discussed. 

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