In a recent paper, we introduced the simultaneous representation problem (defined for any graph class C) and studied the problem for chordal, comparability and permutation graphs. For interval graphs, the problem is defined as follows. Two interval graphs G1 and G2, sharing some vertices I (and the corresponding induced edges), are said to be “simultaneous interval graphs” if there exist interv...

Obstacle representations of graphs have been investigated quite intensely over the last few years. We focus on graphs that can be represented by a single obstacle. Given a (topologically open) polygon C and a finite set P of points in general position in the complement of C, the visibility graph GC(P ) has a vertex for each point in P and an edge pq for any two points p and q in P that can see ...

This paper describes an ultrasensitive surface plasmon resonance (SPR) detection method using biofunctionalized gold nanorods for the direct detection of protein biomarkers. Immunoglobulin E (IgE), which has separate antibody and DNA aptamer binding sites, was chosen as a model protein for which a sandwich assay platform was designed. Detection was achieved via the specific adsorption of unlabe...

Polyacrylamide supports, in a range of pore sizes, were investigated as nucleic acid affinity matrices for the detection of target DNA or RNA sequences using a sandwich hybridization format. Bromoacetyl and thiol oligonucleotide derivatives were covalently linked to sulfhydryl- and bromoacetyl-polyacrylamide supports with greater than 95% end-attachment efficiencies. These polyacrylamide-oligon...

An amplified, indirect biotin-avidin micro-enzyme-linked immunosorbent assay was developed for the measurement of human melanoma-associated antigens, either free or circulating with associated immunoglobulin in patient sera. Parameters and specificity of detection were assessed using monoclonal antibody to human melanoma-associated antigens. The main advantages of the assay are its flexibility,...

A bead-based sedimentation biodetector is studied theoretically. The biodetector operates with a suspension of settling beads, non-settling reporters, and target analytes – all initially suspended in a buffer solution. The reporters can be either fluorescent molecules or small particles. The functionalized beads interact with the reporters and target analytes while settling under the action of ...

Deciding whether a collection of unrooted trees is compatible is a fundamental problem in phylogenetics. Two different graph-theoretic characterizations of tree compatibility have recently been proposed. In one of these, tree compatibility is characterized in terms of the existence of a specific kind of triangulation in a structure known as the display graph. An alternative characterization exp...

The P4-sparse Graph Sandwich Problem asks, given two graphs G 1 = (V, E1) and G2 = (V, E2), whether there exists a graph G = (V, E) such that E1 ⊆ E ⊆ E2 and G is P4-sparse. In this paper we present a polynomial-time algorithm for solving the Graph Sandwich Problem for P4-sparse graphs. c © 2008 Elsevier B.V. All rights reserved.

In this paper we introduce the simultaneous membership problem, defined for any graph class C characterized in terms of representations, e.g. any class of intersection graphs. Two graphs G1 and G2, sharing some vertices X (and the corresponding induced edges), are said to be simultaneous members of graph class C, if there exist representations R1 and R2 of G1 and G2 that are “consistent” on X ....

A graph is a 1-join composition if its vertex set can be partitioned into four nonempty sets AL; AR ; SL and SR such that: every vertex of AL is adjacent to every vertex of AR; no vertex of SL is adjacent to vertex of AR∪SR; no vertex of SR is adjacent to a vertex of AL∪SL. The graph sandwich problem for 1-join composition is de9ned as follows: Given a vertex set V , a forced edge set E, and a ...