A new device for high-pressure freezing of cultured cell monolayer using 10-microm-thin stainless discs as both culture plate and specimen carrier

High-pressure freezing (HPF) has been generally accepted as the most reliable method for cryofixation of biological samples, yielding a deep vitreous freezing. In recent cell biology, mammalian cultured cells are widely used, but HPF of cultured cell monolayer has not reached its full potential. In this study, we developed a new reliable device for HPF of cultured cell monolayer by using a 10-microm-thin stainless disc both as culture plate and specimen carrier. We describe the practical procedure, and demonstrate fine structures of HeLa cells cultured and cryofixed on the stainless discs as results.     

Prediction of space weather by adaptive information processing

Space weather can be predicted using data from satellites. For example, the condition of high-energy electrons at geostationary orbit is vital in providing warnings for spacecraft operations. We investigate an adaptive predictor based on intelligent information processing. The predictor forecasts the condition of high-energy electrons at geostationary orbit 24 h ahead. This article focuses on adaptation and performance of the predictor. Our proposed model succeeded in forecasting the high-energy electron flux at geostationary orbit 24 h ahead. Furthermore, we also consider the relationship between the prediction performance and tuning parameters.     

Spatial strategies in a generalized spatial prisoner’s dilemma

Many strategies, such as tit-for-tat, have been proposed in the iterated prisoner’s dilemma (IPD) in which the prisoner’s dilemma (PD) is carried out repeatedly with two players. A spatial version of the iterated prisoner’s dilemma (SPD) has been studied, where a player at each site plays the IPD game with all the players in the neighborhood. However, the strategies studied in the SPD consider the past actions of a single opponent only. We studied spatial strategies that depend on the configuration of actions taken by all neighbors (as opposed to conventional temporal strategies). Since generosity can be considered as a spatial strategy, we first investigate the generosity required when an action error is involved. We also propose several spatial strategies that outperform many others.This work was presented, in part, at the 9th International Symposium on Artificial Life and Robotics, Oita, Japan, January 28–30, 2004     

A time-dependent threshold condition to determine the onset of AIDS

This study first considers the effects of “uninfectious” HIV-1 due to fatal mutations, and then analysis reveals that AIDS develops when the number of HIV-1 strains, i.e., antigenic diversity, is above a “time-dependent” threshold. This result is interesting because it suggests the possibility that the onset of AIDS could be dynamically determined. This dynamic behavior of the threshold may make the prediction of AIDS development difficult.     

Direct Insight into Near-frictionless Behavior Displayed by Diamond-like Carbon Coatings in Lubricants

Surface physical properties and chemical states on a nanometer scale were investigated to provide a direct insight into the mechanism of near-frictionless performance displayed by diamond-like carbon (DLC) coatings in engine oil lubricants. A mechanism was revealed by combining nanoprobe methods with surface chemical analysis. The near-frictionless behavior observed in the lubricants was found to stem from strong repulsive force between hydrogen-terminated carbon chains, originating from the bonding of oil additive molecules on the DLC coating surface producing sliding contact between H-terminated alkyl chain layers.     

Epidemic models and a self-repairing network with a simple lattice

We have proposed a self-repairing network where nodes are capable of repairing neighboring nodes by mutually copying. A critical point where faulty nodes can be eliminated has been investigated. This paper further studies the dynamics of eradicating faulty nodes by comparing the self-repairing network with mathematical epidemic models such as SIS models. It is shown that the self-repairing network, which is a probabilistic cellular automaton, can be regarded as an epidemic model in some restricted situations. This work was presented in part at the 12th International Symposium on Artificial Life and Robotics. Oita, Japan, January 25–27, 2007