Adaptive polygonization of geometrically constrained surfaces

n -dimensional space, where n>3. This definition can be used for given surfaces that are implicit or parametric. This paper presents a robust, adaptive polygonization algorithm for evaluating and visualizing geometrically constrained surfaces. Let be the constrained surface, a 2-surface in n-space, and let π() be its projection into the subspace spanned by the first three coordinates. Our polygonization algorithm computes π(). The method works directly with the n-space representation, but performs all major computations in 3-space. Techniques for triangulation, polygon decimation, and local refinement are also presented.     

An enhanced timetabling procedure for the no-wait job shop problem: a complete local search approach

In this paper we consider the no-wait job shop problem with a makespan objective. This problem has usually been addressed by its decomposition into a sequencing and a timetabling problem. Here, first we focus on the timetabling problem and take advantage of the symmetry of the problem in order to suggest a new timetabling procedure. Secondly, we suggest embedding this timetabling into a recent metaheuristic named complete local search with memory.     

Das Problem der verantworteten Therapieentscheidung in der Neonatologie

Definition of the problem: Physicians and nurses who work in neonatology—as in intensive care at all—are often forced to decide whether to stop or to continue with the treatment of a severely ill patient. The literature provides several decision making instruments, which are meant to help and to rationalize such decisions. Method and conclusion: Two of these instruments (“Schema zur ethischen Urteilsbildung nach dem Muster der aristotelischen Ethik”, Honnefelder 1994; “Nimwegener Methode für ethische Fallbesprechung”, Gordijn 1998) were tested by retrospectively examining two cases of our NICU. Results of our study show that the use of a decision making instrument is basically helpful. But the above mentioned instruments showed also shortcomings when used in the framework of neonatology. Therefore we developed the “Kölner Arbeitsbogen zur ethischen Entscheidungsfindung in der Neonatologie”, which is adapted to the specific needs of neonatology.     

Accurate marker-free alignment with simultaneous geometry determination and reconstruction of tilt series in electron tomography

An image alignment method for electron tomography is presented which is based on cross-correlation techniques and which includes a simultaneous refinement of the tilt geometry. A coarsely aligned tilt series is iteratively refined with a procedure consisting of two steps for each cycle: area matching and subsequent geometry correction. The first step, area matching, brings into register equivalent specimen regions in all images of the tilt series. It determines four parameters of a linear two-dimensional transformation, not just translation and rotation as is done during the preceding coarse alignment with conventional methods. The refinement procedure also differs from earlier methods in that the alignment references are now computed from already aligned images by reprojection of a backprojected volume. The second step, geometry correction, refines the initially inaccurate estimates of the geometrical parameters, including the direction of the tilt axis, a tilt angle offset, and the inclination of the specimen with respect to the support film or specimen holder. The correction values serve as an indicator for the progress of the refinement. For each new iteration, the correction values are used to compute an updated set of geometry parameters by a least squares fit. Model calculations show that it is essential to refine the geometrical parameters as well as the accurate alignment of the images to obtain a faithful map of the original structure.     

Expression of adhesion molecules in the lower uterine segment during term and preterm parturition

Term and preterm cervical ripening and dilatation have similarities with an inflammatory reaction. Since cell adhesion molecules are involved in this process, investigations on the expression of intercellular adhesion molecule-1, endothelial leukocyte adhesion molecule-1, vascular cell adhesion molecule-1, and platelet endothelial cell adhesion molecule in the lower uterine segment and in vitro experiments on human umbilical vein endothelial cells were performed. In addition, current reports on expression of endothelial adhesion molecules by the uterine cervix were summarized. Cell adhesion molecule expression by lower uterine segment and uterine cervix in term and preterm parturition was measured using immunohistochemistry, enzyme immunoassay, and Northern blot analysis. Regulation of adhesion molecule expression was evaluated in vitro by indirect immunofluorescence and flow cytometry using human umbilical vein endothelial cells. Investigations in term parturition revealed that intercellular adhesion molecule-1, endothelial leukocyte adhesion molecule-1, and vascular cell adhesion molecule-1 expression increases during parturition. In preterm labor, the expression of endothelial leukocyte adhesion molecule-1 and intercellular adhesion molecule-1 in the lower uterine segment increased. Expression of platelet endothelial cell adhesion molecule did not change in term and preterm parturition. Expression of adhesion molecules was localized mainly on lower uterine segment vascular endothelial cells and to a smaller extent on leukocytes. In vitro experiments showed that expression of adhesion molecules by human umbilical vein endothelial cells can be stimulated by tumor necrosis factor-alpha, 17beta-estradiol, prostaglandin E(2), and the antigestagen onapristone. Progesterone exerted no stimulatory effect. Cervical ripening and dilatation during term and preterm parturition are associated with an increased expression of endothelial cell adhesion molecules by lower uterine segment and uterine cervix. The expression can be modulated by pro-inflammatory cytokines, sex hormones, and prostaglandin E(2). Mechanisms controlling the extravasation of leukocytes may play a fundamental role in term and preterm parturition.