Improved Stratification of Autonomic Regulation for risk prediction in post-infarction patients with preserved left ventricular function (ISAR-Risk)

Aims To investigate the combination of heart rate turbulence (HRT) and deceleration capacity (DC) as risk predictors in post-infarction patients with left ventricular ejection fraction (LVEF) > 30%. Methods and results We enrolled 2343 consecutive survivors of acute myocardial infarction (MI) (30% (cumulative 5-year mortality rates of 37.9% and 7.8%, respectively). Among patients with LVEF > 30%, SAF identified another high-risk group of 117 patients with 37 deaths (cumulative 5-year mortality rates of 38.6% and 6.1%, respectively). Merging both high-risk groups (i.e. LVEF ≤ 30% and/or SAF) doubled the sensitivity of mortality prediction compared with LVEF ≤ 30% alone (21.1% vs. 42.1%, P 30%, SAF identifies a high-risk group equivalent in size and mortality risk to patients with LVEF ≤ 30%

Comparative expression pattern of Matrix-Metalloproteinases in human glioblastoma cell-lines and primary cultures

<p>Abstract</p> <p>Background</p> <p>Glioblastomas (GBM), the most frequent malignant brain tumors in adults, are characterized by an aggressive local growth pattern and highly invasive tumor cells. This invasion is facilitated by expression of matrix metalloproteinases (MMPs), a family of zinc-dependent endopeptidases. They mediate the degradation of protein components of the extracellular matrix. Twenty-three family members are known. Elevated levels of several of them have been reported in GBM. GBM cell-lines are used for <it>in vitro </it>studies of cell migration and invasion. Therefore, it is essential to know their MMP expression patterns. Only limited data for some of the cell-lines are published, yet. To fill the gaps in our knowledge would help to choose suitable model systems for analysis of regulation and function of MMPs during GBM tumorigenesis, cell migration and invasion.</p> <p>Findings</p> <p>We analysed MMP-1, -8, -9, -10, -11, -13, -17, -19, -20, -21, -23, -24, -26, -27, and MMP-28 expression in seven GBM cell-lines (SNB-19, GaMG, U251, U87, U373, U343, U138) and in four primary cell cultures by semiquantitative RT-PCR, followed changes in the MMP expression pattern with increasing passages of cell culture and examined the influence of TNF-α and TGF-β1 stimulation on the expression of selected MMPs in U251 and U373 cells.</p> <p>MMP-13, -17, -19 and -24 were expressed by all analyzed cell-lines, whereas MMP-20 and MMP-21 were not expressed by any of them. The other MMPs showed variable expression, which was dependent on passage number. Primary cells displayed a similar MMP-expression pattern as the cell-lines. In U251 and U373 cells expression of MMP-9 and MMP-19 was stimulated by TNF-α. MMP-1 mRNA expression was significantly increased in U373 cells, but not in U251 cells by this cytokine. Whereas TGF-β1 had no impact on MMP expression in U251 cells, it significantly induced MMP-11 and MMP-24 expression in U373 cells.</p> <p>Conclusions</p> <p>Literature-data and our own results suggest that the expression pattern of MMPs is highly variable, dependent on the cell-line and the cell-culture conditions used and that also regulation of MMP expression by cytokines is cell-line dependent. This is of high impact for the transfer of cell-culture experiments to clinical implementation.</p

Visible spectrum quantum light sources based on InxGa1–xN/GaN Quantum Dots

We present a method for designing quantum light sources, emitting in the visible band, using wurtzite InxGa1−xN quantum dots (QDs) in a GaN matrix. This system is significantly more versatile than previously proposed arsenide- and phosphide-based QDs, having a tuning range exceeding 1 eV. The quantum mechanical configuration interaction method, capturing the fermionic nature of electrons and associated quantum effects explicitly, is used to find shapes and compositions of dots to maximize the excitonic dipole matrix element and optimize the biexciton binding energy. These results provide QD morphologies tailored for either bright single-photon emission or entangledphoton- pair emission at any given wavelength in the visible spectrum

On Transfer Blocking and Minimal Blocking in Serial Manufacturing Systems -- The Impact of Buffer Allocation

In this paper we investigate the impact of buffer allocation in an unbalanced, asynchronous production system consisting of 12 stages arranged in series. We consider finite buffer tandem queue like arrangements as well as the singlecard kanban system. The first belongs to the class of manufacturing systems operating in push mode, while the latter is a means for the implementation of the just-in-time (JIT) philosophy. We discuss how given parameters influence the performance of the systems under consideration. Finally, we present guidelines how designers and operations managers of a flow shop manufacturing system can maximize throughput while keeping WIP and the cycle time at a low level

On Transfer Blocking and Minimal Blocking In Serial . . .

In this paper we investigate the impact of buffer allocation in an unbalanced, asynchronous production system consisting of 12 stages arranged in series. We consider finite buffer tandem queue like arrangements as well as the single card kanban system. The first belongs to the class of manufacturing systems operating in push mode, while the latter is a means for the implementation of the just-in-time (JIT) philosophy. We discuss how given parameters influence the performance of the systems under consideration. Finally, we present guidelines how designers and operations managers of a flowshop manufacturing system can maximize throughput while keeping WIP and the cycle time at a low level

Performance Modelling of Pull Manufacturing Systems with Batch Servers and Assembly-like Structure

The manufacturing industries&apos; need to focus on reducing work-in-process (WIP) as well as product cycle times has led to a widespread employment of the just--in-- time (JIT) production philosophy and in particular kanban systems. Queueing models of several differentkanban systems have been previously presented focusing on single job service machines. We extend the model and approximation method presented by Mitra and Mitrani, to investigate a singlecard kanban system with batch servers. Batchservers are machines that can process several jobs or lots at a time. We use the same technique to analyze assembly--likemanufacturing systems and manufacturing systems with more than only one machine in eachkanban cell. We compare numerical approximations with simulations of the configurations under consideration. We also discuss how given parameters influence performance measures suchas production rate (throughput), cycle time, and WIP. This study was motivated by the need of semiconductor manufacturers for kanban--like pull production control systems

An Approach For The Performance Evaluation Of Workflow Models

Many companies are reengineering their business processes to improve business performance. Often pictorial descriptions of the processes are used to understand the as-is structure and to conduct what-if analysis. We propose a colored stochastic Petri Net (CGSPN) approach to model enterprise workflow that is formally defined by a process model graph (PMgraph) . Dynamic performance studies can then be carried out by means of simulation. Due to the state space explosion exact steady-state analysis of the underlying stochastic process can be provided for small processes only. We propose a load-equivalent aggregation (LEA) of single classes of work items for an approximate solution. The LEA allows the substitution of processes by their aggregated model of less complexity while preserving the load inducing behavior. INTRODUCTION Due to permanent changing market conditions the organization of a company has to be under continuous consideration and performance evaluation to ensure operational..

A Petri Net Approach for the Performance Analysis of Business Processes

Recently, many companies have realized that their organization needs to be improved in order to enhance flexibility, efficiency, and effectiveness. Business Process Re-engineering has become the new organization paradigm to reconstitute profitability and competitiveness. Additionally, workflow management systems promise to provide a conceptual framework to describe and automate workflow. Analysts are asking for methods to evaluate alternative process designs for performance objectives, such as cycle time and throughput. These measures are dependent on the dynamic behavior of a process and can hardly be derived by traditional methods. In this paper we will outline an approach to model the dynamic behavior of business processes by Stochastic Petri nets. Our aim is to provide workflow management systems with an analytical evaluation component. We will summarize the problems we encountered following our approach to give directions for further research