To investigate the possible binding mode of E-64 (N-[N-(L-3-trans-carboxyoxirane-2-carbonyl)-L-leucyl]agmatine), a potent cysteine protease inhibitor, to papain active site, molecular dynamics simulations were applied to two complex forms : R- and S- configurational forms of E-64 C2 atom for the covalent bond formation with the papain Cys-25 SH group. The tertiary structures of the papain-E-64 complexes were built by visual interactive modelling and the energy minimization technique, and were subjected to the dynamics simulations of 10 ps. Although no significant difference was observed between the potential energies of energy-minimized R- and S-complex forms, the molecular dynamics simulations suggested that the hydrogen bonding mode of the former form is more advantageous than that of the latter one. Comparing with the hydrogen bonds observed in the papain-E-64 complex crystal, it could be concluded that the present molecular dynamics simulation reflects well the three-dimensional structure concerning the interaction of E-64 with the papain active site. The conformational characteristics of E-64 and its possible interaction mode with papain were also discussed.
To contribute to research on the effective practice of pharmaceutical law, we analyzed the learner characteristics that influence learning outcomes in this field at Kitasato University School of Pharmacy. Specifically, we conducted a forced entry multiple regression analysis. The explanatory variables were the learner's gender, course, university entrance examination format, course year progression, completion of related subjects, and submission of class quizzes, while examination performance in pharmaceutical law was the response variable. The learners' course of study and submission of class quizzes were found to have a significant influence on the examination results. The examination performance of students enrolled in a four-year course was 14.4% lower than students enrolled in a six-year course, while students with records of not submitting the class quizzes scored 8.4% lower than those who submitted all the quizzes. It is probable that there was a fundamental difference between the academic ability of the students enrolled in the two courses that affected the examination results. The fact that the submission of class quizzes had an effect on the examination results may be useful in developing a learning guide for the students. To further enhance the evidence of the analysis of learner characteristics in this field, obtaining the results of joint research with other universities is necessary.
This paper presents a basic study for developing a new adhesion improvement method for railway vehicles, focusing on the tangential force characteristics between wheels and rails. In our previous studies, the following phenomena have been confirmed. First, the tangential force of the wheel/rail is increased by repeated rolling and sliding frictional force, and the tangential force is stabilized by the oxide film covering the contact surface. In addition, the tangential force under the condition where the humidity around the contact surface is low tends to be larger than that under high humidity condition. And finally, these phenomena indicate that the friction coefficient of wheel/rail can be increased by instantaneously reducing the humidity around the contact surface. Therefore, in this paper, we propose a method for improving the frictional force that reflects the above-mentioned results in our previous studies. In the proposed method, assuming that it is applied to re-adhesion control of railway vehicles, the frictional force of the wheel/rail contact is temporarily increased by lowering the humidity around the contact surface by injecting dry nitrogen gas less than 30% humidity. To verify the proposed method, using a pair of the small cylindrical specimen, tangential force was measured under the conditions with different humidity. In addition, in order to confirm the effect on the braking performance of actual railway vehicle, numerical analysis was carried out. As a result, the experimental result showed the frictional force is increased by up to approximately 40% under high humidity condition, and it was confirmed by the numerical analysis that the proposed method has an improvement effect on the reduction of braking distance during dry nitrogen gas injection even if the humidity condition around the contact surface is high.
In this paper, we propose a video scene annotation method based on tag clouds. First, user comments associated with a video are collected from existing video sharing services. Next, a tag cloud is generated from these user comments. The tag cloud is displayed on the video window of the Web browser. When users click on a tag included in the tag cloud while watching the video, the tag gets associated with the time point of the video. Users can share the information on the tags that have already been clicked. We confirmed that the coverage of annotations generated by this method is higher than that of the existing methods, and users are motivated to add tags by sharing tag clouds. This method will contribute to advanced video applications.
In this paper, in order to investigate a contact area between the measured profile of wheel and the designed shape of rail, we carried out calculation of the contact area strictly by a general software program, which applied the boundary element method and half-infinite body approximation. In addition, a calculation method of a creep coefficient is proposed with focus on contact areas between actual wheel and rail. Moreover, we also carried out numerical simulation of the running stability to find out how the difference of a value of an estimated creep coefficient has influence on the running stability of railway vehicle. As a result, it is shown that the contact area between the actual wheel and the rail has the shape composed of many contact areas, and the estimated creep coefficient may be smaller than the Kalker's theoretical value due to the influence of fine unevenness of wheel tread. Furthermore, we describes that the proposed method make the evaluation on running stability on the safety side.
