Inability of Lyapunov exponents to predict epileptic seizures

It has been claimed that Lyapunov exponents computed from electroencephalogram or electrocorticogram (ECoG) time series are useful for early prediction of epileptic seizures. We show, by utilizing a paradigmatic chaotic system, that there are two major obstacles that can fundamentally hinder the predictive power of Lyapunov exponents computed from time series: finite-time statistical fluctuations and noise. A case study with an ECoG signal recorded from a patient with epilepsy is presented.     

Increased phase synchronization of spontaneous calcium oscillations in epileptic human versus normal rat astrocyte cultures

Stochastic synchronization analysis is applied to intracellular calcium oscillations in astrocyte cultures prepared from epileptic human temporal lobe. The same methods are applied to astrocyte cultures prepared from normal rat hippocampus. Our results indicate that phase-repulsive coupling in epileptic human astrocyte cultures is stronger, leading to an increased synchronization in epileptic human compared to normal rat astrocyte cultures.     

Brain weight differences associated with induced focal microgyria

Background  

Disrupting neural migration with bilateral focal freezing necrosis on postnatal day 1 (P1) results in the formation of 4-layered microgyria. This developmental injury triggers a pervasive neural reorganization, which is evident at the electrophysiological, behavioral, and anatomical levels. In this experiment, we investigated changes in brain weight as an index of global disruption of neural systems caused by focal damage to the developing cortical plate.     

Efficient Protection in MPλS Networks Using Backup Trees: Part One—Concepts and Heuristics

Multi-protocol lambda switching (MPS) has recently been applied in the optical network control plane to provide fast lightpath provisioning. As an increasing amount of traffic is carried in optical transport networks (OTNs), single network failures can affect a vast amount of traffic, making lightpath protection crucial. Therefore, shared backup tree (BT) lightpath protection is a promising paradigm in MPS networks due to its ability of fast recovery and its efficiency in consumed resources. A shared BT is used to protect a group of working lightpaths towards the same destination. From the working lightpaths in such a group, only one affected lightpath at a time can be recovered using the BT. The main problem is how to group and route the working paths (WPs) and how to route the BTs, in such a way that the capacity resources used by the WPs and the BTs are minimized. In Part One of this study (presented in this paper), we propose three approaches to cope with this problem. The first approach is a purely integer linear programming (ILP) based method. The second one is a combination of ILP and a heuristic technique. The last one is a purely heuristic approach. In this paper, these approaches are theoretically compared. In Part Two [1] of this study, several simulations are carried out in order to compare these approaches in terms of performance and computing effort. The experimental results are in line with the theoretical expectations.     

Inhibition study of angiotensin converting enzyme by capillary electrophoresis after enzymatic reaction at capillary inlet

Capillary electrophoresis was used to study the inhibition of angiotensin-converting enzyme (ACE) by different inhibitors. Reaction occurred at the capillary inlet during a predetermined waiting period, followed by the electrophoretic separation of the reaction compounds. ACE activity was determined by the quantification of the reaction product, hippuric acid, at 230 nm. The technique was used to study the potency of five different inhibitors (captopril, lisinopril, perindoprilat, quinaprilat and benazeprilat). During a kinetic study, the Ki value of captopril was estimated to be 55.4 +/- 8.8 nM, a value consistent with previously reported values.     

Advances in capillary electrophoretically mediated microanalysis

Recent developments in the use of capillary electrophoretic techniques for the in-line study of enzyme reactions and derivatization protocols are reviewed. The article is divided into two parts: (i) in-line enzyme reactions and (ii) in-line derivatization. The first part introduces electrophoretically mediated microanalysis (EMMA) and discusses and illustrates the different modes of EMMA. A literature overview is provided, starting from 1996, and the investigated enzymes are classified into two tables based on the mode of engagement (i.e., continuous or transient) of the developed EMMA-based assay. The second part starts with an introduction of the procedures and the nomenclature used in the area of in-line derivatization protocols based on EMMA. Reported derivatization procedures are discussed and classified in tables, according to the functional group that is derivatized.     

Europeanist-programme roadmap for optical communications generated by theoptimist thematic network

On the basis of Europeanist project results in the field of photonics, theoptimist thematic network has produced a roadmap for optical communications. This work is described in the present article which provides scenarios for the evolution of the optical network in the coming 10 years. Predictable developments in optical components, sub-systems and systems and their consequences on the architecture and performances of the networks are analysed. Specific interest is focused on the various parts of the network structure namely the access, the metropolitan area, the wide area and the global networks. Technical documents elaborated by theoptimist consortium and minutes fromist workshops can be found on the website http://www.ist-optimist.org/.[1]. They constitute a main source for further information.     

Optimal visual perception and detection of oral cavity neoplasia

The most common way to detect disease is by visual inspection of the suspect tissue. However, the human eye is not optimized for this task because the perceived spectrum of light is divided into three channels, all of which have overlapping spectral sensitivity curves. Here, we present new methods to optimize visually perceived contrast based on spectral differences between normal and abnormal tissue. We apply these methods to the perception of fluorescence emission from the oral cavity. Abnormalities in the oral cavity are optimally perceived when the excitation is between nm. To optimally visualize fluorescence at 340-nm excitation, the emission should be observed through a blue bandpass filter transmitting light at 430 nm.     

Mathematics in Context: Measurement,Packaging and Caring for Our Environment

The purpose of this article is to present illustrative examples which will help teachers and teacher educators combine mathematics and science through the activities which involve higher order thinking and worthwhile tasks. Packaging provides an important and meaningful context for exploring important mathematics and an important environmental issue.