A multi-objective differential evolutionary approach toward more stable gene regulatory networks

Models are of central importance in many scientific contexts. Mathematical and computational modeling of genetic regulatory networks promises to uncover the fundamental principles of living systems. Biological models, such as gene regulatory models, can help us better understand interactions among genes and how cells regulate their production of proteins and enzymes. One feature shared among living systems is their ability to cope with perturbations and remain stable, a property that is the result of evolutionary fine-tuning over many generations. In this study we use random Boolean networks (RBNs) as an abstract model of gene regulatory systems. By applying Differential Evolution (DE), an evolution-based optimization technique, we produce networks with increased stability. DE requires relatively few user-specified parameters, has fast convergence and does not rely on initial conditions to find the global minima within multi-dimensional search spaces.     

Entrapment of an air gun pellet between the thyroid cartilage and the lining mucosa in a patient with a penetrating neck injury: a case report

ABSTRACT: INTRODUCTION: Air guns, either modern or traditional models, are powerful weapons that are capable ofcausing serious or life-threatening injuries. CASE PRESENTATION: Here, we present a case of an air gun pellet injury, with the pellet trapped between the thyroidcartilage and the lining mucosa of a 58-year-old Iranian man. CONCLUSION: Entrapment of air gun pellet between thyroid cartilage and the lining mucosa, as presented inour case, may cause diagnostic challenges through the clinical presentation of slightodynophagia.     

Molecular dynamics analysis of a ribonuclease C-peptide analogue

We have carried out a nanosecond molecular dynamics simulation of an analogue of the ribonuclease C-peptide in water. The overall conformation has an extended region for the first three amino acids connected to an α-helix for residues 4–13, and this basic structure is preserved throughout the simulation, with helical hydrogen bonds present 87% of the time, on average. The final helical hydrogen bond is spontaneously broken and re-formed several times, providing a detailed picture of such winding/unwinding events. The simulation was used to estimate the effects of internal motion on proton nuclear Overhauser effect spectroscopy (NOESY) intensities for several classes of important cross peaks. Within the helical regions, the effects of internal motion vary only a little from one residue to another for backbone–backbone cross peaks, and the relevant correlation functions reach plateau values within about 50 ps. The spectral simulations show, however, that it may be difficult to establish a close quantitative connection between NOESY cross-peak volumes and measures of helical content. © 1993 John Wiley & Sons, Inc.