Layer matrix

The second method is sandwich method which was developed from the two-layer method and used first for the analysis of the single mammalian cell lysates [67], The first thin layer is formed by the matrix-only solution. It is followed by deposition of the analyte solution and then deposition of second layer of matrix on the top of analyte layer. The sample is basically sandwiched between the two matrix layers and preparation results in a matrix-sample-matrix sandwich. This method is specifically used for detecting protein and peptides [67-69], The three-layer matrix-sample preparation method was also used as matrix-matrix-sample mode [70],... 

Han and Schey [71] used a special matrix coating method in processing the bovine lenses sections (30 10 pm) for MS imaging. The tissue sections were first sprayed with an acetonitrile-water (50 50, vol/vol) solution resulting in a tightly bound section. After drying, the tissue sections were coated with a thin layer matrix of S A at 15 mg/mL in ethanol-water (50 50, vol/vol). After it was dried, the tissue sections were finally sprayed with several cycles of SA matrix solution at 15 mg/mL in ethanol-water-formic acid (44 44 12, vol/vol/vol). 

Keller B, Li L (2006) Three-layer matrix/sample preparation method for MALDI MS analysis of low nanomolar protein samples. J Am Soc Mass Spectrom 17 780-785. doi 10.1016/j. jasms.2006.02.012... 

By using the interface matrix and the layer matrix of (6.1) and (6.5), the total system transfer matrix (scattering matrix) S, which relates the electric field on the ambient and substrate sides by... 

Streubel, A., Siepmann, J., Peppas, N., and Bodmeier, R., Bimodal drug release achieved with multi-layer matrix tablets transport mechanisms and device design, Journal of Controlled Release, Vol. 69, No. 3, 2000, pp. 455-468. 

Bowden-Young steric constant steric descriptors (O Charton steric constant) branching index Randic connectivity index - connectivity indices branching layer matrix layer matrices... 

F matrix -> layer matrices ( cardinality layer matrix)... 

A molecular descriptor derived from the - cardinality layer matrix LC of a molecular graph (7 defined as - mean information content [Konstantinova, 1996] ... 

A layer matrix LM of a - molecular graph (7 is a rectangular unsymmetric matrix Ax(D + 1), A being the number of molecule atoms and D the topological diameter. The entry i-k (Imu ) is the sum of the weights of the vertices located in the concentric shell (layer) at topological distance k around the vertex v, [Diudea et al., 1991 Diu-dea, 1994 Skorobogatov and Dobrynin, 1988]. The kth layer of the vertex v, is the set of vertices defined as follows ... 

The columns of the layer matrix are D + 1, D being the topological diameter, and the case A = 0 is also considered, meaning that the property of the focused ith atom is also considered. 

The simplest layer matrix obtained weighting all atoms by a weight equal to one. Therefore, the entry i-k of the matrix is the number /c,a.- of atoms located at distance k from the focused ith vertex. For the cardinality layer matrix the following relations... 

The cardinality layer matrix was originally called the k matrix [Skorobogatov and Dobrynin, 1988] and F matrix [Diudea and PSrv, 1988]. 

By this matrix, the - information layer index is calculated. Moreover, four different local vertex invariants derived from the cardinality layer matrix have been proposed [Wang et al., 1994] as follows ... 

Similar to the branching layer matrix, this matrix is obtained weighting the atoms by their - valence vertex degree b instead of the simple vertex degree b [Hu and Xu, 1996]. 

A layer matrix whose entry i-k is defined as the sum of the conventional bond order ji of the bonds connecting the vertices situated in the kth layer with the vertices of the (k - l)th layer with respect to the focused ith vertex [Hu and Xu, 1996]. 

To increase the discriminating power of atomic and molecular descriptors derived from the layer matrices the sum layer matrix LS was also defined, and its entries are the sums of the corresponding entries of the branching layer matrix LB (/h, ) and edge layer matrix LE (fe, ) [Diudea et al., 1991] ... 

A layer matrix obtained weighting the atoms by their -> vertex distance degree o, i.e. the row sum of the -> distance matrix D [Balaban and Diudea, 1993]. Therefore, the entry i-k of the layer matrix is the sum of the vertex distance degrees of the atoms located at distance k from the focused ith vertex. It is obvious that the entries of the first column k = 0) are only vertex distance degrees. Moreover, the sums over each row in LDS are all equal to twice the -> Wiener index, i.e. the following relation holds ... 

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