A box graph is the intersection graph of orthogonal rectangles in the plane. We consider such basic combinatorial problems on box graphs as maximum independent set, minimum vertex cover and maximum induced subgraph with polynomial-time testable hereditary property Pi. We show that they can be exactly solved in subexponential time, more precisely, in time 2(O(rootnlog n)), by applying Miller's simp

In a joint experimental and theoretical work the optical response and excited-state character of two novel conjugated polymers for photovoltaic applications are studied. The polymers, alternating polyfluorene (APFO) Green 1 and APFO Green 2, are both copolymers of fluorene, thiophene, and electron accepting groups. The band gaps are extended into the red and near infrared with onsets of 780 and 10

One of the central tenets in life-history theory is that there is a trade-off between current and future reproduction (i.e. a cost of reproduction). The mechanism for this cost of reproduction is, however, largely unknown. One hypothesis is that the high workload during reproduction compromises resistance to parasites and that the resulting increase in parasitaemia has negative effects on the pros

A numerical study of the mechanical behavior of heterogeneous soil systems, consisting of a bulk of sand with embedded stiff gravel inclusions or soft clay inclusions, is performed. A solution scheme using parallel computing is employed when analyzing two different categories of problems. First, a homogenization problem is studied, where use of a single representative volume element subjected to p

The influence of a poly(styrene-graft-ethylene oxide) (P(S-g-EO)) copolymer on poly(2,6-dimethyl-p-phenylene oxide)/poly(methyl methacrylate) (PPO/PMMA) blends was studied by a number of different techniques in order to characterize the properties of the interphase. Scanning electron microscopy shows that the copolymer reduces the dispersed phase size, and dynamic mechanical spectroscopy (DMS) rev

Inhibitor of DNA binding (Id) proteins function as inhibitors of members of the basic helix-loop-helix family of transcription factors and have been demonstrated to play an important role in regulating lymphopoiesis. However, the role of these proteins in regulation of myelopoiesis is currently unclear. In this study, we have investigated the role of Id1 and Id2 in the regulation of granulopoiesis

Background information. Transmembrane water flow is aided by water-specific channel proteins, aquaporins. Plant genomes code for approx. 35 expressed and functional aquaporin isoforms. Plant aquaporins fall into four different subfamilies of which the PIPS (plasma membrane intrinsic proteins) constitute the largest and evolutionarily most conserved subfamily with 13 members in Arabidopsis and maiz

Biomagnification and polychlorinated biphenyl (PCB) congener distribution was examined in a predator-prey, host-parasite system, in which Atlantic salmon (Salmo salar) preyed upon sprat (Sprattus sprattus). Eubothrium crassum was an intestinal parasite in salmon that also "preyed upon" sprat, because the parasites gained access to foodstuffs via the host (salmon) gut. Salmon contained significantl

By the sequential action of dCTP deaminase and dUTPase, dCTP is converted to dUMP, the precursor of thymidine nucleotides. In addition, dUTPase has an essential role as a safeguard against uracil incorporation in DNA. The putative dCTP deaminase (MJ0430) and dUTPase (MJ1102) from the hyperthermophilic archaeon Methanocaldococcus jannaschii were overproduced in Escherichia coli. Unexpectedly, we fo

The retrovirus forms its envelope by budding at the plasma membrane (PM). This process is primarily driven by its cytoplasmic core-precursor protein, Gag, as shown by the efficient formation of virus-like Gag particles in the absence of its envelope protein, Env. Most interestingly, several studies have demonstrated incorporation of various PM proteins into retrovirus, but the underlying mechanism

The structure and phase behavior of oppositely charged macroions in solution have been studied with Monte Carlo simulations using the primitive model where the macroions and small ions are described as charged hard spheres. Size and charge symmetric, size asymmetric, and charge asymmetric macroions at different electrostatic coupling strengths are considered, and the properties of the solutions ha

Aim: To identify important predictors among lifestyle behaviours and physiological factors of bone mineral density (BMD) in relation to body mass index (BMI) among young women over a 2-year period. Design, sample and measurements: Data were collected in 1999 and 2001. Healthy young women (n=152) completed a questionnaire. BMD measurements were performed by DEXA in the calcaneus. The women were su

Objective. To investigate the occurrence of extraarticular manifestations (ExRA) in it well defined community based cohort of patients with rheumatoid arthritis (RA), and to examine their effect on mortality, Methods. Using the resources of the Rochester Epidemiology Project. a retrospective medical record review was conducted of a cohort of 424 cases of RA in Olmsted County, MN, USA, diagnosed du

The organization of the mitochondrial genome is generally very conserved among vertebrates. Because of this, examination of the rare rearrangements which do occur has been suggested as offering a powerful alternative to phylogenetic analyses of mitochondrial DNA sequences. Here, we report on an avian mitochondrial rearrangement in a group of oscine passerines (warblers of the genus Phylloscopus).

Inter-atrial conduction delay in patients with atrial fibrillation (AF) has been reported. However, the area of this conduction delay has not been well identified. The activation time and conduction velocity over the right atrial endocardium were evaluated during sinus rhythm using the CARTO mapping technique in 6 patients with paroxysmal AF (AF group) and 11 patients without history of AF (contro