This study aims to characterize the tungsten-urea analyte indicator electrode. The method used is biosensor potentiometry with urease enzyme immobilization technique. electrode was coated PVA-enzyme glutaraldehyde (GA) 2.9% PVC-KTpClPB- o-NPOE variation of 61% and 66%. Characterization electrodes using SEM-EDS, FTIR XRD analysis. A1-4 sample 1x 1x, 61%. A3-4 3x Likewise, reasoning samples 66% T...

background and objectives: lipases are valuable biocatalysts which are widely used in the detergent, food, dairy and pharmaceutical industries. the aims of the present study included the isolation of a lipase-producer from industrial zones and the partial characterization of the enzyme. materials and methods: a number of bacteria were isolated from sites related to the oil industries. an isolat...

Many factors influence the near-field visualization of plasmonic structures that are based on perforated elliptical slits. Here, characterization errors are experimentally analyzed in detail from both fabrication and measurement points of view. Some issues such as geometrical parameter, probe-sample surface interaction, misalignment, stigmation, and internal stress, have influence on the final ...

For various graph-theoretic properties P that impose upper bounds on the minimum degree or the size of a neighbourhood set, we characterize the class %(P’) (%((P’)) of graphs G such that G and all its subgraphs (subcontractions) have property P. For example, if P is “6 <xn” (6 = minimum degree, n = number of vertices, 0 <X < 1) then S(P’) = F(K,+,), the class of graphs that do not have K,,, as ...

We study which infinite posets have simple cofinal subsets such as chains, or decompose canonically into such subsets. The posets of countable cofinality admitting such a decomposition are characterized by a forbidden substructure; the corresponding problem for uncountable cofinality remains open.

In this thesis we consider ordered graphs (that is, graphs with a fixed linear ordering on their vertices). We summarize and further investigations on the number of edges an ordered graph may have while avoiding a fixed forbidden ordered graph as a subgraph. In particular, we take a step toward confirming a conjecture of Pach and Tardos [12] regarding the number of edges allowed when the forbid...

Clique-width is a graph parameter with many algorithmic applications. For a positive integer k, the k-th power of a graph G is the graph with the same vertex set as G, in which two distinct vertices are adjacent if and only if they are at distance at most k in G. Many graph algorithmic problems can be expressed in terms of graph powers. We initiate the study of graph classes of power-bounded cl...

We prove a precise characterization of toroidal graphs with no K3,3-subdivisions in terms of forbidden minors and subdivisions. The corresponding lists of four forbidden minors and eleven forbidden subdivisions are shown.

An additive hereditary graph property is any class of simple graphs, which is closed under isomorphisms unions and taking subgraphs. Let La denote a class of all such properties. In the paper, we consider Hreducible over La properties with H being a fixed graph. The finiteness of the sets of all minimal forbidden graphs is analyzed for such properties.

We investigate which switching classes do not contain a bipartite graph. Our final aim is a characterization by means of a set of critically non-bipartite graphs: they do not have a bipartite switch, but every induced proper subgraph does. In addition to the odd cycles, we list a number of exceptional cases and prove that these are indeed critically non-bipartite. Finally, we give a number of s...