Masato Masuya

Characteristic temperatures of folding of a small peptide

We perform a generalized-ensemble simulation of a small peptide taking the interactions among all atoms into account. From this simulation we obtain thermodynamic quantities over a wide range of temperatures. In particular, we show that the folding of a small peptide is a multistage process associated with two characteristic temperatures, the collapse temperature Ttheta and the folding temperature T. Our results give supporting evidence for the energy landscape picture and funnel concept. These ideas were previously developed in the context of studies of simplified protein models, and here are checked in an all-atom Monte Carlo simulation.

Molecular dynamics of C-peptide of ribonuclease A studied by replica-exchange Monte Carlo method and diffusion theory

Generalized-ensemble algorithm and diffusion theory have been combined in order to compute the dynamical properties monitored by nuclear magnetic resonance (NMR) experiments from efficient and reliable evaluation of statistical averages. Replica-exchange Monte Carlo simulations have been performed with a C-peptide analogue of ribonuclease A, and the Smoluchowski diffusion equation has been applied. A fairly good agreement between the calculated and measured 1H-NOESY NMR cross peaks has been obtained. The combination of these advanced and continuously improving statistical tools allows the calculation of a wide variety of dynamical properties routinely obtained by experiments.

β-sheet formation in BPTI(16–36) by Monte Carlo simulated annealing

Abstract Performing Monte Carlo simulated annealing simulations of a peptide fragment BPTI(16–36) from randomly chosen initial conformations, we have obtained a β-sheet structure as the lowest-energy conformation. The solvent effects were included by the term that is proportional to the solvent-accessible surface area. This lowest-energy structure has a type II′ β-turn and three characteristic intrachain hydrogen bonds that connect the two β-strands. It turns out that the positions of the reverse turn and hydrogen bonds are in remarkable agreement with the implications of an NMR experiment of the same fragment.

An experience of monitoring university network security using a commercial service and DIY monitoring

Monitoring network security of a university is one of the most important jobs for the network managers. Without the monitoring, it is hard to keep the network safe. It is common that the security policy of a university has the term which states that monitoring network security is a mandate. However it is very hard to monitor every part of a universitys network by the limited number of staff and a limited amount of time and expense. In order to cope with these problems, we bought a commercial network security monitoring service for the doorway of our campus network and we are doing Do It Yourself (DIY) monitoring with free software for the inside of the network. By the commercial monitoring service, we could reach 24 hours a day and 365 days a year monitoring at the doorway. By the DIY monitoring, we could realize the precise monitoring of inside network, which is hard to realize by the commercial monitoring, because there are Network Address Translations (NATs). If an incident was found by the combination of these monitoring, we could deal with it as fast as we can. By these efforts, there was no serious incident such as unauthorized manipulation of important web pages by crackers and leaking serious personal information by using P2P file sharing software last year. In this paper, we report the experience of our monitoring.

Enhancing information security of a university using computer ethics video clips, managed security service and an information security management system

An experience of enhancing information security for the ICT service department of a Japanese national university corporation is described. Information security is realized by the integration of people, processes, and technology. In order to enhance the peoples side of information security, we have been using digital video clips, which are produced by a group of faculty members of Japanese universities. In order to enhance the technology side of information security, we have been using a managed security service and other means. We could reach 24 hours a day and 365 days a year monitoring at the doorway of the university using the service. However, we had no standard means to enhance the process side of information security until recently. This deficiency became an obstacle to making agreements between other universities on inter-university activities. This need also may be an obstacle to gaining reliance from users. In order to cope with this problem, we have decided to implement an information security management system (ISMS). It takes a lot of time and work to implement the ISMS. However, many parts of the ISMS were processes that we were already doing without any clear rules. The ISMS helps not only enhance information security but also improve daily work and management of the staff.

Easy Human Visual MTF Measurements

This investigation concerns measurement of the human visual MTF properties using a computer display. At the beginning of the 21st century, 30% of the Japanese population will be over 50 years old. One of the countermeasures for visual degradation is the improvement of displayed pictures. The human visual MTF properties are fundamental data for this improvement. In this paper, easy MTF measurement is discussed in comparison with precise MTF measurement. In the framework of this study, subjects were distinguished in the following way: people over fifty years old are referred to as“aged” and those around twenty years old are called”young”.