Compression-based fixed-parameter algorithms for feedback vertex set and edge bipartization

We show that the NP-complete Feedback Vertex Set problem, which asks for the smallest set of vertices to remove from a graph to destroy all cycles, is deterministically solvable in O(ck⋅m) time. Here, m denotes the number of graph edges, k denotes the size of the feedback vertex set searched for, and c is a constant. We extend this to an algorithm enumerating all solutions in O(dk⋅m) time for a (larger) constant d. As a further result, we present a fixed-parameter algorithm with runtime O(k²⋅m²) for the NP-complete Edge Bipartization problem, which asks for at most k edges to remove from a graph to make it bipartite.     

Semantic-Web-Technologien in der Arbeitsplatzvermittlung

Zusammenfassung The importance of the Internet for job procurement is increasing for the reason that three quarters of the people in the employment age are online. On the other hand because ever more companies are publishing their job offers on the Web. However, due to the large number of openings published online it is almost impossible for job seekers and job portals to gain an overview of the entire employment market. Since job offers lack semantically meaningful annotations, the search and integration into databases are made highly difficult. Applying Semantic Web technologies to the e-recruitment process provides advantages for all participants in the market. In this paper we describe a method for analysing the domain-specific language of an application domain. We use this method to describe the e-recruitment process and the necessary ontologies for annotating job offers and job applications. In conclusion, we present the prototypical implementation of the scenario based on Semantic Web, especially semantic matching.     

Cost-effectiveness of therapies for patients with nonvalvular atrial fibrillation

BACKGROUND: The most appropriate treatment(s) for patients with atrial fibrillation remains uncertain. OBJECTIVE: To examine the cost-effectiveness of anti-thrombotic and antiarrhythmic treatment strategies for atrial fibrillation. METHODS: We performed decision and cost-effectiveness analyses using a Markov state transition model. We gathered data from the English-language literature using MEDLINE searches and bibliographies from selected articles. We obtained financial data from nationwide physician-fee references, a medical center's cost accounting system, and one of New England's larger managed care organizations. We examined strategies that included combinations of cardioversion, antiarrhythmic therapy with quinidine, sotalol hydrochloride, or amiodarone, and anticoagulant or antiplatelet therapy. RESULTS: For a 65-year-old man with nonvalvular atrial fibrillation, any intervention results in a significant gain in quality-adjusted life years (QALYs) compared with no specific therapy. Use of aspirin results in the largest incremental gain (1.2 QALYs). Cardioversion followed by the use of amiodarone and warfarin together is the most effective strategy, yielding a gain of 2.3 QALYs compared with no specific therapy. The marginal cost-effectiveness ratios of cardioversion followed by aspirin, with or without amiodarone, are $33800 per QALY and $10800 per QALY, respectively. Cardioversion followed by amiodarone and warfarin has a marginal cost-effectiveness ratio of $92400 per QALY compared with amiodarone and aspirin. Strategies that include cardioversion followed by either quinidine or sotalol are both more expensive and less effective than competing strategies. CONCLUSIONS: Cardioversion of patients with nonvalvular atrial fibrillation followed by the use of aspirin alone or with amiodarone has a reasonable marginal cost-effectiveness ratio. While cardioversion followed by the use of amiodarone and warfarin results in the greatest gain in quality-adjusted life expectancy, it is expensive (ie, has a high marginal cost-effectiveness ratio) compared with aspirin and amiodarone. Finally, for patients who are bothered little by symptoms of atrial fibrillation, cardioversion followed by either aspirin or warfarin without subsequent antiarrhythmic therapy is the treatment of choice.     

Morphology and function of rooster efferent ductule epithelial cells in culture

Regulation of the excurrent ducts of the testis is not well understood, particularly in avian species. To investigate the role of steroid hormones in the male reproductive tract, we developed a primary cell culture of epithelia isolated from rooster ductuli efferentes (efferent ductules). Efferent ductules of the avian testis comprise 77% of the epididymal region and form a mass of tubules containing a heavily folded epithelium enmeshed in connective tissue. The epididymal region was separated by microdissection and small epithelial plaques isolated by serial digestion with collagenase, elastase and repeated pipetting. Isolated cell plaques were cultured in a bicameral chamber on Millicell-CM inserts coated with two layers of basement membrane matrix, consisting primarily of laminin and Types I and IV collagen. Active ciliary beat was observed before plating and this activity was maintained for 14 days in culture. Cell plaques attached within 24 h and outgrowths formed a confluent monolayer by 5-6 days. The epithelial nature of cultured cells was demonstrated by immunocytochemical staining for cytokeratin. Light and electron microscopy confirmed that morphology and polarity of the original epithelial cells were maintained in culture. Cultured efferent ductal epithelium was cuboidal in shape and maintained many of the cytoplasmic organelles typical of these cells in vivo. The uptake of cationic ferritin indicated the endocytotic activity of these cultured cells was maintained. Estrogen receptor mRNA expression was maintained in cultured cells. These data demonstrate avian efferent ductal epithelium can be isolated and grown in defined culture medium for the purpose of determining the role of hormones and other factors in regulating the function of the epididymal region in the bird.     

Mould Allergy in Schoolchildren in Relation to Airborne Fungi and Residential Characteristics in Homes and Schools in Northern Norway

Abstract During winter, airborne microfungi were collected from the homes and schools of 19 children sensitized to house dust mites (HDM) and 19 non-atopic control children in the community of Sør-Varanger, northern Norway. The samples were cultivated and microfungal growth was identified microscopically. Indoor humidity, temperature, carbon dioxide (CO₂), allergic symptoms and sensitization were registered. Symptom data and information concerning sociodemographic and housing conditions were obtained using a questionnaire. Penicillium was the most common microfungus in both homes and schools, followed by different yeasts, Aspergillus, Cladosporium and Mucor. The number of infected homes was equal in the HDM-sensitized and in the control group, but the mean aerospore counts were higher in the HDM-sensitized than in the control group. The lowest aerospore counts were found in the schools. High airborne spore counts appeared to be related to high indoor humidity. Only four children were sensitized to fungi, and these children were also sensitized to other allergens, such as animal dander and pollen, and suffered from asthma, allergic rhinoconjuncitivits (AR) and atopic dermatitis (AD). Three of these four children also had high counts of aerospores in their homes. However, no consistent association between mould growth and sensitization to moulds could be observed. The health implications of indoor fungal exposure may be multifactorial.     

Connective tissue growth factor: a novel regulator of mucosal repair and fibrosis in inflammatory bowel disease?

Inflammatory bowel disease (IBD) is a multifactorial disorder which is characterized by massive damage of the epithelium and the underlying mesenchyme of the intestine. Due to the potent effect of connective tissue growth factor (CTGF) on fibroblast proliferation and connective tissue deposition we speculated about a possible role of this mitogen in IBD. Here we demonstrate a strikingly increased expression of CTGF mRNA in surgical specimens of patients suffering from two forms of IBD, Crohn's disease and ulcerative colitis. In most specimens, the levels of CTGF mRNA correlated with the degree of inflammation as assessed by histological analysis of adjacent tissue samples and by expression analysis of the pro-inflammatory cytokine interleukin-1 beta. However, areas of little inflammation which were characterized by severe fibrosis also revealed high levels of CTGF mRNA. Expression of transforming growth factor beta-1 (TGF-beta 1), the only known inducer of CTGF so far, as well as of the CTGF target genes collagen I alpha 1, fibronectin and integrin alpha 5 revealed a strong correlation with the expression of CTGF. These data suggest a prominent role of CTGF in the repair of mucosal injury in IBD and in the aberrant deposition of extracellular matrix leading to fibrosis and stenosis, one major complication in IBD, especially in Crohn's disease.     

Avian germinal disc region secretes factors that stimulate proliferation and inhibit progesterone production by granulosa cells

Microscopic analysis of ovarian follicles in the domestic hen has revealed differences in the cellular structure of granulosa cells that are dependent upon the location of granulosa cells relative to the germinal disc, which contains the female gamete. These differences appear as a morphological gradient, which implies variations in granulosa cell function. This observation prompted us to hypothesize that the germinal disc region (GDR) of the avian preovulatory follicle participates in the process of follicular growth by producing factors that act in a paracrine manner to stimulate proliferation of and inhibit steroidogenesis in the granulosa layer, establishing a gradient in the morphology and physiology of the granulosa layer. To test our hypothesis, we asked two questions: 1) Are physiological gradients of proliferation and steroidogenesis present within the granulosa layer of a preovulatory follicle? 2) Does the GDR secrete factors that affect granulosa cell proliferation and/or steroidogenesis? Incorporation of 3H-thymidine was used as a measure of proliferation, and production of progesterone was used as a measure of steroidogenesis. In the first experiment, 8-mm-diameter sections were obtained from three morphologically distinct regions of the granulosa monolayer: 1) the GDR, 2) granulosa cells distal to the GDR (distal granulosa) and 3) granulosa cells midway between the GDR and distal granulosa cells (proximal granulosa cells). The GDR incorporated the most 3H-thymidine and produced the least progesterone. Distal granulosa cells incorporated the least 3H-thymidine and produced the most progesterone. Proximal granulosa cells incorporated an intermediate amount of 3H-thymidine and produced an intermediate amount of progesterone. To answer the second question, conditioned medium was prepared from GDRs and distal granulosa cells (control) obtained from the F1 (largest preovulatory follicle) and F3 (the third-largest preovulatory follicle) follicles. Sections (8-mm in diameter) of the distal granulosa layer (F3 for 3H-thymidine incorporation, F1 for progesterone production) were incubated in GDR-conditioned medium or granulosa cell-conditioned medium to determine whether factors secreted into the medium by the GDR and distal granulosa cells affect granulosa cell proliferation and/or steroidogenesis. Certain samples of GDR-conditioned medium and granulosa cell-conditioned medium were boiled, protease-treated or charcoal-stripped. F3 and F1 GDRs produced heat- and protease-sensitive factors that promoted proliferation and inhibited progesterone production by granulosa cells. These data indicate that diametrically opposed gradients of proliferation and steroidogenesis are present within the granulosa layer of an individual preovulatory follicle. Furthermore, the GDR produces proliferation-stimulating and steroidogenesis-inhibiting factors that may act in an autocrine or paracrine manner to influence proliferation and steroidogenesis in granulosa cells.