Discrete event simulations for glycolysis pathway and energy balance

In this report, the biological network of the glycolysis pathway has been modeled using discrete event models (DEMs). The most important feature of this pathway is that energy is released. To create a stable steady-state system an energy molecule equilibrating enzyme and metabolic reactions have been added, resulting in the energy balance system. Stability and stochastic in uences on the results have been investigated and result in an unstable system, except for a small region of input parameters. To stabilize the energy balance system some feedback regulators are presented. It is shown that stochastic behavior has got a signicant in uence on a otherwise stable biological system

Feedback and reversibility in substrate-enzyme reactions as discrete event models

A dierent approach in modeling reactions between substrate molecules and enzymes is presented in this report. The reactions are modeled using a discrete event model (DEM), mostly used in manufacturing or queueing systems. The DEM has been validated with the most used approach to modeling substrate-enzyme reactions, a set of ordinary dierential equations (ODEs). The substrate-enzyme model is extended with feedback of substrate and=or product molecules on the enzyme, resulting in inhibition or activation of the enzyme. A reversible reaction, where the enzyme can react with both the substrate and the product, is also modeled as a DEM and validated with an ODE model. The substrate-enzyme reaction models with feedback is extended to a steady-state system by adding a generator, convertor and exit. Stability of the steady-state system is analyzed and resulted in three distinct regions

Digitisation and 3D reconstruction of 30 year old microscopic sections of human embryo, foetus and orbit

A collection of 2200 microscopic sections was recently recovered at the Netherlands Ophthalmic Research Institute and the Department of Anatomy and Embryology of the Academic Medical Centre in Amsterdam. The sections were created thirty years ago and constitute the largest and most detailed study of human orbital anatomy to date. In order to preserve the collection, it was digitised. This paper documents a practical approach to the automatic reconstruction of a 3- D representation of the original objects from the digitised sections. To illustrate the results of our approach, we show a multi-planar reconstruction and a 3-D direct volume rendering of a reconstructed foetal head

First LOFAR results on galaxy clusters

Deep radio observations of galaxy clusters have revealed the existence of diffuse radio sources related to the presence of relativistic electrons and weak magnetic fields in the intracluster volume. The role played by this non-thermal intracluster component on the thermodynamical evolution of galaxy clusters is debated, with important implications for cosmological and astrophysical studies of the largest gravitationally bound structures of the Universe. The low surface brightness and steep spectra of diffuse cluster radio sources make them more easily detectable at low-frequencies. LOFAR is the first instrument able to detect diffuse radio emission in hundreds of massive galaxy clusters up to their formation epoch. We present the first observations of clusters imaged by LOFAR and the huge perspectives opened by this instrument for non-thermal cluster studies.Comment: Proceedings of the 2012 week of the French Society of Astronomy and Astrophysics (SF2A) held in Nice, June 5th-8t

LOFAR: Early imaging results from commissioning for Cygnus A

Contains fulltext : 91984.pdf (preprint version ) (Open Access

Observer design for networks and distributed control

No abstract

Observer design for networks and distributed control

No abstract

Discrete event simulations for glycolysis pathway and energy balance

In this report, the biological network of the glycolysis pathway has been modeled using discrete event models (DEMs). The most important feature of this pathway is that energy is released. To create a stable steady-state system an energy molecule equilibrating enzyme and metabolic reactions have been added, resulting in the energy balance system. Stability and stochastic in uences on the results have been investigated and result in an unstable system, except for a small region of input parameters. To stabilize the energy balance system some feedback regulators are presented. It is shown that stochastic behavior has got a signicant in uence on a otherwise stable biological system