Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles: DFG German National Licenses  (3)
  • Facets of Polyhedra  (2)
  • Antiangiogenesis  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 33 (1985), S. 28-42 
    ISSN: 1436-4646
    Keywords: Acyclic Subgraph Problem ; Feedback Arc Set Problem ; Facets of Polyhedra ; Polynomial Time Algorithms ; Weakly Acyclic Digraphs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract The acyclic subgraph problem can be formulated as follows. Given a digraph with arc weights, find a set of arcs containing no directed cycle and having maximum total weight. We investigate this problem from a polyhedral point of view and determine several classes of facets for the associated acyclic subgraph polytope. We also show that the separation problem for the facet defining dicycle inequalities can be solved in polynomial time. This implies that the acyclic subgraph problem can be solved in polynomial time for weakly acyclic digraphs. This generalizes a result of Lucchesi for planar digraphs.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 33 (1985), S. 43-60 
    ISSN: 1436-4646
    Keywords: Facets of Polyhedra ; Linear Ordering Problem ; Triangulation Problem ; Permutation Problem
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract LetD n be the complete digraph onn nodes, and letP LO n denote the convex hull of all incidence vectors of arc sets of linear orderings of the nodes ofD n (i.e. these are exactly the acyclic tournaments ofD n ). We show that various classes of inequalities define facets ofP LO n , e.g. the 3-dicycle inequalities, the simplek-fence inequalities and various Möbius ladder inequalities, and we discuss the use of these inequalities in cutting plane approaches to the triangulation problem of input-output matrices, i.e. the solution of permutation resp. linear ordering problems.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Der Hautarzt 50 (1999), S. 848-852 
    ISSN: 1432-1173
    Keywords: Schlüsselwörter Malignes Melanom ; Mikrozirkulation ; Angiogenese ; Antiangiogenese ; Tumorassoziierte Gefäßneubildung ; Key words Malignant melanoma ; Microcirculation ; Angiogenesis ; Antiangiogenesis ; Tumour-associated neoangiogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The microcirculation of human skin tumours can be visualized with noninvasive methods from clinical microcirculation research (capillaroscopy and laser Doppler fluxmetry (LDF). The latter can also be used to measure the blood flow in such tumours. This prospective study was designed to evaluate melanoma-associated cutaneous neoangiogenesis. We studied the microcirculation of 114 pigmented skin tumours in 103 patients (63 women, 40 men) averaging 38.8±21.1 years of age. On the basis of histological findings, we diagnosed melanocytic naevus in 86 cases and malignant melanoma in 28. The malignant melanoma was characterized by a chaotic arrangement of the capillaries, which were dilated and formed corkscrew-shaped or glomerular structures. In the transitional area between healthy and cancerous areas there was hypervascularization. The capillaries of the melanoma appeared to be more permeable towards the low-molecular-weight, water-soluble sodium fluorescein. Laser Doppler flux, a measure of cutaneous circulation in the upper 2 mm of the skin, is higher in the centre of the melanoma than in either the middle of a melanocytic naevus (p〈0.0005) or in neighbouring healthy skin areas (p〈0.005). In the future, antiangiogenetic therapy strategies could play a significant role in the treatment of malignant melanoma. These methods provide a reliable means of evaluating the specific antiangiogenetic efficacy of treatments for cutaneous melanoma.
    Notes: Zusammenfassung Die Mikrozirkulation von Hauttumoren des Menschen kann nichtinvasiv mit den Methoden der klinischen Mikrozirkulationsforschung [Kapillarmikroskopie, Laser-Doppler-Fluxmetrie (LDF)] visualisiert und der Blutstrom mittels Laser-Doppler-Fluxmetrie gemessen werden. Die Melanom-assoziierte kutane Gefäßneubildung ist Gegenstand dieser prospektiven Studie. Die Mikrozirkulation von 114 pigmentierten Hauttumoren von 103 Patienten (63 Frauen; 40 Männer) mit einem mittleren Alter von 38,8±21,1 Jahren wurde untersucht. Histologisch ergab sich in 86 Fällen die Diagnose eines Naevuszellnaevus (NZN), in 28 Fällen die eines malignen Melanoms. Das maligne Melanom war durch eine chaotische Anordnung von Kapillaren charakterisiert. Die melanomassoziierten Kapillaren waren dilatiert, verliefen korkenzieherartig und bildeten glomerulumartige Formationen. Am Übergang zur gesunden Haut fand sich eine Hypervaskularisation. Die Kapillaren des Melanoms scheinen für das kleinmolekulare wasserlösliche Na-fluoreszein vermehrt durchlässig zu sein. Der Laser-Doppler-Flux, ein Maß für die Hautdurchblutung bis zu einer Tiefe von 2 mm, ist in der Mitte des Melanoms erhöht, sowohl im Vergleich zur Mitte von gutartigen NZN (p〈0,0005) als auch im Vergleich zu gesunder benachbarter Haut (p〈0,005). Antiangiogenetische Therapiekonzepte könnten für die Behandlung des malignen Melanoms Bedeutung erlangen. Mit Hilfe der vorgestellten Untersuchungsmethoden ließe sich die spezifische antiangiogenetische Wirksamkeit an kutanen Melanomen zuverlässig beurteilen.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...