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Application of Density Based Clustering to Microarray Data Analysis

Raczynski L., Wozniak K., Rubel T., Zaremba K.

International Journal of Electronics and Telecommunications

2010

Vol. 56, No. 3

281-286

In just a few years, gene expression microarrays have rapidly become a standard experimental tool in the biological and medical research. Microarray experiments are being increasingly carried out to address the wide range of problems, including the cluster analysis. The estimation of the number of clusters in datasets is one of the main problems of clustering microarrays. As a supplement to the existing methods we suggest the use of a density based clustering technique DBSCAN that automatically defines the number of clusters. The DBSCAN and other existing methods were compared using the microarray data from two datasets used for diagnosis of leukemia and lung cancer.

Influence of Intermolecular Interactions on Nuclear Magnetic Shielding Constans of OCS

Jackowski K., Les A., Makulski W., Wozniak K.

Polish Journal of Chemistry

2002

Vol. 76 / nr 4

575-580

The gauge-included atomic orbital (GIAO) method has been applied within the coupled Hartree-Fock (CHF) approximation to compute 13C, 17Oand 33SNMRchemical shifts for solid OCS. Increasing clusters of OCS molecules taken out of crystal lattice have been used in an additive approximation to estimate the effect of intermolecular interactions on shielding of the carbon, oxygen and sulphur nuclei. There is a very good agreement achieved for NMR chemical shifts between the results of calculations and experimental measurements obtained for 13C and also some discrepancies for 17Oand 33S nuclei, probably due to deficiency of ab-initio calculations (lack of electron correlation). The results reveal that the 33S NMR signal of OCS is strongly dependent on intermolecular interactions.