Feasibility issues in shortest-path routing with traffic flow split

In the Internet’s autonomous systems packets are routed on shortest paths to their destinations. A related problem is how to find an admissible traffic routing configuration using paths that can be generated by a system of weights assigned to IP links. This problem is NP-hard. It can be formulated as a mixed-integer program and attempted with a branch-and-cut algorithm if effective cuts (valid inequalities) can be derived. In this paper we discuss admissibility of shortest-path routing configurations represented by binary variables specifying whether or not a particular link is on a shortest path to a particular destination. We present a linear programming problem for testing routing admissibility and derive solutions of this problem which characterize non-admissible routing configurations

Enhancement of cartilage repair through the addition of growth plate chondrocytes in an immature skeleton animal model

Background: The treatment of articular cartilage damage is a major clinical problem. More often, this clinical issue affects children, which forces doctors to find the best treatment method. Methods: The aim of this experimental study on 2-month-old Landrace pigs was to compare the results of two cartilage defect treatments: (1) filling the cartilage defect with a scaffold incubated with bone marrow aspirate supplemented with growth plate chondrocytes (the CELLS group) and (2) filling the cartilage defect with an empty scaffold implanted after drilling the subchondral bone (the CTRL group). The treatment outcomes were assessed macroscopically and microscopically. Results: Based on the macroscopic evaluation, all animals showed a nearly normal morphology, with an average of 9.66/12 points (CTRL) and 10.44/12 points (CELLS). Based on the microscopic evaluation, 1 very good result and 8 good results were obtained in the CTRL group, with an average of 70.44%, while 5 very good results and 4 good results were obtained in the CELLS group, with an average of 79.61%. Conclusions: (1) Growth plate chondrocytes have high chondrogenic potential and thus offer new possibilities for cartilage cell therapy. (2) The implantation of a scaffold loaded with bone marrow-derived MSCs (mesenchymal stem cells) and growth plate chondrocytes into a cartilage defect is a good therapeutic method in immature patients. (3) Cartilage repair based on a scaffold with bone marrow aspirate-derived cells supplemented with autologous growth plate chondrocytes achieves better results than repair with marrow stimulation and a hyaluronic acid-based scaffold (overall microscopic rating). (4) Chondrocyte clustering is a manifestation of the cartilage repair process but requires further observation

An evaluation of health-related quality of life of patients aroused from prolonged coma when treated by physiotherapists with or without training in the "Academy of Life" programme

Objective: To evaluate the health-related quality of life (HRQOL) in patients aroused from prolonged coma after a severe traumatic brain injury (TBI) treated by physiotherapists trained in the ‘Academy of Life’ programme. It was assumed that physiotherapists who acquired this knowledge and experience would create a better therapeutic milieu, and would be more effective than physiotherapists who had not received this training. Material and methods: 40 patients who had suffered a severe TBI in a motor vehicle accident and had been aroused from prolonged coma were examined. All the patients underwent long-term rehabilitation according to a standard, phased programme. They were divided into two numerically even groups: an experimental group, treated by therapists trained in the ‘Academy of Life’ programme, and a control group, treated by physiotherapists who were not trained in this programme. The research instruments included an analysis of documentation, a structured clinical interview, and the Quality of Life Scale. Results: As hypothesized, the experimental group showed significant improvement in HRQOL, whereas in the control group improvement was statistically non-significant. Conclusions: The patients from the experimental group, treated by physiotherapists trained in the ‘Academy of Life’, obtained a significantly greater improvement in physical and social functioning, and thus in HRQOL, than patients from the control group

Telecommunications network design and max-min optimization problem, Journal of Telecommunications and Information Technology, 2005, nr 3

Telecommunications networks are facing increasing demand for Internet services. Therefore, the problem of telecommunications network design with the objective to maximize service data flows and provide fair treatment of all services is very up-to-date. In this application, the so-called maxmin fair (MMF) solution concept is widely used to formulate the resource allocation scheme. It assumes that the worst service performance is maximized and the solution is additionally regularized with the lexicographic maximization of the second worst performance, the third one, etc. In this paper we discuss solution algorithms for MMF problems related to telecommunications network design. Due to lexicographic maximization of ordered quantities, theMMF solution concept cannot be tackled by the standard optimization model (mathematical programme). However, one can formulate a sequential lexicographic optimization procedure. The basic procedure is applicable only for convex models, thus it allows to deal with basic design problems but fails if practical discrete restrictions commonly arriving in telecommunications network design are to be taken into account. Then, however, alternative sequential approaches allowing to solve non-convex MMF problems can be used

Classification system of the tibiofibular syndesmosis blood supply and its clinical relevance

Due to the lack of anatomical studies concerning complexity of the tibiofibular syndesmosis blood supply, density of blood vessels with further organization of syndesmotic vascular variations is presented in clinically relevant classification system. The material for the study was obtained from cadaveric dissections. We dissected 50 human ankles observing different types of arterial blood supply. Our classification system is based on the vascular variations of the anterior aspect of tibiofibular syndesmosis and corresponds with vascular density. According to our study the mean vascular density of tibiofibular syndesmosis is relatively low (4.4%) and depends on the type of blood supply. The highest density was observed among ankles with complete vasculature and the lowest when lateral anterior malleolar artery was absent (5.8% vs. 3.5%, respectively). Awareness of various types of tibiofibular syndesmosis arterial blood supply is essential for orthopedic surgeons who operate in the ankle region and radiologists for the anatomic evaluation of this area. Knowledge about possible variations along with relatively low density of vessels may contribute to modification of treatment approach by the increase of the recommended time of syndesmotic screw stabilization in order to prevent healing complications