Influx of immunoglobulins from the vascular compartment into a grafted cornea

PURPOSE: To determine the effect of a fresh corneal wound or a healed corneal scar on the immunodiffusion of immunoglobulins into the cornea. METHODS: F344 rats were immunized with human serum albumin (HSA) 1 week before an autologous rotational keratoplasty of the right cornea or 1 year after an autograft was performed. One group of rats also was treated with gentamicin-dexamethasone ointment in the grafted eye for 1 week after transplantation to reduce the postsurgical inflammatory signs. A serum sample was drawn every week and booster injections with HSA were given after 2 and 3 weeks. At various times after immunization, groups of rats were killed, blood and aqueous humor samples were taken, and the corneas of both eyes were removed. The corneas were divided into the graft or a 3-mm central button and the peripheral rim and weighed. The anti-HSA titer was determined in serum, aqueous humor, and both parts of the corneas. RESULTS: Up to 5 weeks after transplantation, the grafted cornea contained more anti-HSA immunoglobulins than did the control eye. One year postgrafting, no difference was seen. In the first weeks after keratoplasty, influx of anti-HSA from the peripheral into the central cornea was, however, neither obstructed nor enhanced. CONCLUSIONS: Surgical trauma in itself causes increased influx of anti-HSA immunoglobulins into the cornea. Within the cornea, a wound or a scar does not appear to be a barrier for centripetal immunoglobulin diffusion.     

Regional labour market dynamics in the Netherlands

This article analyzes the response of regional labor markets in the Netherlands to region-specific labor demand shocks. Previous studies show remarkable differences in response between regions in European countries and regions in the United States. The analysis shows that, in Dutch regions, the speed of adjustment is similar to that of the US, but the primary adjustment mechanism is the same as in Europe. Whereas previous studies analyze only average patterns of all regions in a country, we also provide a more in-depth analysis of within country differences in labor market adjustment processes, thus showing remarkable differences between regions within the Netherlands.     

Spatial and annual variability in concentrations and sources of Escherichia coli in multiple watersheds

Nonpoint source fecal contamination is a concern for drinking water supplies worldwide. In this study, 4812 E. coli isolates were classified to source. Results of this experiment show that the fecal coliform (FC) counts varied by year, month, and site, for each of the watersheds sampled. For both years, the lowest FC counts tended to be at the highest elevation sites followed by the drinking water intake sites at the lowest elevation. The highest FC counts tended to be at the mid-elevation sites on BX, Deer, and Duteau Creeks. The sources of E. coli varied significantly with stream for 2003 and 2004 (P < 0.001, df = 39), although the main sources of E. coli (avian, deer/elk, canine, rodent, bovine, and bear) tended to be similar between watersheds. The dominant sources of E. coli changed from 2003 (avian, deer/elk, and canine) to 2004 (avian, bovine, and rodent). It is important to look at the results of more than 1 year of source tracking data to get a better picture of the dominant sources within a watershed. Overall, wildlife was the largest contributor of E. coli to the watersheds in both 2003 (> 84%) and 2004 (> 73%).     

A Generalization of AT-Free Graphs and a Generic Algorithm for Solving Triangulation Problems

Abstract. A subset A of the vertices of a graph G is an asteroidal set if for each vertex a ∈ A a connected component of G-N[a] exists containing A\backslash{a} . An asteroidal set of cardinality three is called asteriodal triple and graphs without an asteriodal triple are called AT-free . The maximum cardinality of an asteroidal set of G , denoted by \an(G) , is said to be the asteriodal number of G . We present a scheme for designing algorithms for triangulation problems on graphs. As a consequence, we obtain algorithms to compute graph parameters such as treewidth, minimum fill-in and vertex ranking number. The running time of these algorithms is a polynomial (of degree asteriodal number plus a small constant) in the number of vertices and the number of minimal separators of the input graph.     

Updating the complexity status of coloring graphs without a fixed induced linear forest

A graph is H-free if it does not contain an induced subgraph isomorphic to the graph H. The graph P_k denotes a path on k vertices. The ?-Coloring problem is the problem to decide whether a graph can be colored with at most ? colors such that adjacent vertices receive different colors. We show that 4-Coloring is NP-complete for P₈-free graphs. This improves a result of Le, Randerath, and Schiermeyer, who showed that 4-Coloring is NP-complete for P₉-free graphs, and a result of Woeginger and Sgall, who showed that 5-Coloring is NP-complete for P₈-free graphs. Additionally, we prove that the precoloring extension version of 4-Coloring is NP-complete for P₇-free graphs, but that the precoloring extension version of 3-Coloring can be solved in polynomial time for (P₂+P₄)-free graphs, a subclass of P₇-free graphs. Here P₂+P₄ denotes the disjoint union of a P₂ and a P₄. We denote the disjoint union of s copies of a P₃ by sP₃ and involve Ramsey numbers to prove that the precoloring extension version of 3-Coloring can be solved in polynomial time for sP₃-free graphs for any fixed s. Combining our last two results with known results yields a complete complexity classification of (precoloring extension of) 3-Coloring for H-free graphs when H is a fixed graph on at most 6 vertices: the problem is polynomial-time solvable if H is a linear forest; otherwise it is NP-complete.     

THE ELASTICITY AND EFFICIENCY OF JOB MATCHING IN DUTCH REGIONAL LABOUR MARKETS

ABSTRACT In many matching function studies, the measure of job matches and the stock of job searchers dues not correspond New hires or filled vacancies are related to unemployed job searchers only, whereas this should be the total stock of job searchers, as any job searcher, besides unemployed, can be hired or fill a vacancy. Furthermore, in many studies the matching function exhibits constant returns to scale. We show that there is a relation between the choice of variables representing matches and job searchers and the returns to scale of the matching function. If only unemployed are assumed to search for a job, then a matching function of total hires with constant returns to scale yields a matching function of hires from unemployment with decreasing returns to scale. A matching function is estimated, which corroborates this point, using quarterly regional data for The Netherlands The differences between our model and other regional matching studies can be linked to the role that employed job searchers and job searchers not in the labour force play in the matching process. It implies that if policy measures to improve the functioning of the regional labour market are required, they are best addressed to the northern provinces in The Netherlands.     

A Generalization of AT-Free Graphs and a Generic Algorithm for Solving Triangulation Problems

A subset A of the vertices of a graph G is an asteroidal set if for each vertex a ∈ A a connected component of G-N[a] exists containing A\backslash{a} . An asteroidal set of cardinality three is called asteriodal triple and graphs without an asteriodal triple are called AT-free . The maximum cardinality of an asteroidal set of G , denoted by \an(G) , is said to be the asteriodal number of G . We present a scheme for designing algorithms for triangulation problems on graphs. As a consequence, we obtain algorithms to compute graph parameters such as treewidth, minimum fill-in and vertex ranking number. The running time of these algorithms is a polynomial (of degree asteriodal number plus a small constant) in the number of vertices and the number of minimal separators of the input graph.     

Mixing Action and Evaluation of Tablet Lubricants in Direct Compression

The effect of a series of modern lubricants during mixing on both lubricating action and binding properties of a direct compressible tablet formulation has bean investigated and compared with the effect of magnesium stearate. Lubricants which gave the best lubricating action (magnesium stearate, hydrogenated vegetable oils and glycerides) caused the largest reduction in tablet strength with an increase in. mixing time. When used in concentrations of It. the hydrogenated vegetable oils and glycerides tested gave about the same reduction of the ejection force as 0.5% magnesiun stearate, but their effect on tablet hardness during mixing was much smaller. This result was conflrmed for three direct compressible tablet formulations, composed with different excipients, where magnesium stearate could be replaced advantageously by Boeson VP or sterotex.     

Planar Graph Coloring Avoiding Monochromatic Subgraphs: Trees and Paths Make It Difficult

We consider the problem of coloring a planar graph with the minimum number of colors so that each color class avoids one or more forbidden graphs as subgraphs. We perform a detailed study of the computational complexity of this problem. We present a complete picture for the case with a single forbidden connected (induced or noninduced) subgraph. The 2-coloring problem is NP-hard if the forbidden subgraph is a tree with at least two edges, and it is polynomially solvable in all other cases. The 3-coloring problem is NP-hard if the forbidden subgraph is a path with at least one edge, and it is polynomially solvable in all other cases. We also derive results for several forbidden sets of cycles. In particular, we prove that it is NP-complete to decide if a planar graph can be 2-colored so that no cycle of length at most 5 is monochromatic.