Counter‐ion‐specific helix formation of poly(γ‐methyl L‐glutamate) derivatives containing sulfonate group in aqueous alcohols

Charged polypeptides containing sulfonate groups were prepared by transesterification of poly(γ‐methyl L ‐glutamate) with isethionic acid. The coil–helix transition of the sulfonated polypeptides was investigated in aqueous alcohols. Marked counter‐ion specificity was observed for helix formation: Li⁺ < Na⁺ < Cs⁺ ≦ Rb⁺ ≦ K⁺; this was different to that for poly(L ‐glutamate) (PLG): Cs⁺ ? K⁺ < Li⁺ < Na⁺. Specific helix stabilization by counter‐ion mixing, which has been found for the PLG system, was not observed for the sulfonated polypeptides. The counter‐ion‐ and solvent‐specific helix formation is discussed and compared with that in PLG. © 2001 Society of Chemical Industry     

Evaluation of cost reduction potential for 1 kW class SOFC stack production: Implications for SOFC technology scenario

Recently, a commercial version of a residential solid oxide fuel cell (SOFC) system with a flat tubular cell has been developed. However, the system cost still remains very high, which is a barrier to its widespread use. In this study, the potential for cost reductions in SOFC stack production was investigated in order to contribute to the viability of the widespread use of such residential SOFC systems in future. A cost analysis of 700 W SOFC stack production based on a process integration modeling was conducted. The present bottom–up approach enabled us to perform a sensitivity analysis with a variety of parameters in terms of cell design, the production process and cell performance. This allowed us to investigate the effects of these factors on the production cost, thereby revealing the quantitative impact of each technological improvement on the cost reduction potential. The present analysis also revealed innovation pathways which could result in technology scenarios where residential SOFC systems could reach a break-even point in comparison with the baseload electricity cost. The analysis of the cost reduction potential presented here provides a useful viewpoint for developing a research strategy for state-of-the-art SOFC technology.     

Bacteriophages isolated from activated sludge processes and their polyvalency

In this study, bacteriophages were isolated from activated sludge and their host range was studied. Bacterial isolates were obtained from an activated sludge process treating urban sewage, and bacteriophages were obtained by plaque assay using the bacterial isolates obtained in this study as the host. Out of 15 bacteria isolated, 9 supported plaque formation. The host range test was conducted with a combination of 8 bacteriophage isolates and 9 bacterial isolates. All of the 8 bacteriophages tested were found to form plaques on more than 1 host, and 4 of them formed plaques on both gram-positive and gram-negative bacterial isolates. Three of the 8 bacteriophages failed to form plaques on their original bacterial host. The experimental result indicates that bacteriophages are an active part of the activated sludge microbial ecosystem, having a very close ecological relationship with their host bacteria.     

Location-based services in ubiquitous computing environments

This paper presents a framework for providing dynamically deployable services in ubiquitous computing settings. The goal of the framework is to provide people, places, and objects with computational functionalities to support and annotate them. Using RFID-based tracking systems, the framework detects the locations of physical entities, such as people or things, and deploys services bound to the entities at proper computing devices near where they are located. It enables location-based and personalized information services to be implemented as mobile agents and operated at stationary or mobile computing devices, which are at appropriate locations, even if the services do not have any location-information. This paper presents the rationale, design, implementation, and applications of our prototype infrastructure.     

Acrobot control by learning the switching of multiple controllers

Reinforcement learning (RL) has been applied to constructing controllers for nonlinear systems in recent years. Since RL methods do not require an exact dynamics model of the controlled object, they have a higher flexibility and potential for adaptation to uncertain or nonstationary environments than methods based on traditional control theory. If the target system has a continuous state space whose dynamic characteristics are nonlinear, however, RL methods often suffer from unstable learning processes. For this reason, it is difficult to apply RL methods to control tasks in the real world. In order to overcome the disadvantage of RL methods, we propose an RL scheme combining multiple controllers, each of which is constructed based on traditional control theory. We then apply it to a swinging-up and stabilizing task of an acrobot with a limited torque, which is a typical but difficult task in the field of nonlinear control theory. Our simulation result showed that our method was able to realize stable learning and to achieve fairly good control.This work was presented, in part, at the 9th International Symposium on Artificial Life and Robotics, Oita, Japan, January 28–30, 2004     

Elimination of artifacts in MRCP: technical consideration

Artifacts of MR cholangiopancreatography (MRCP) include fluid-filled gastrointestinal tracts, respiratory motion artifacts, spasm of Oddi's sphincter, vascular compression of bile ducts, overlapping of various anatomical structures and bright signal of surrounding fatty tissue. In this article, various technical considerations to eliminate these artifacts were described for the better imaging analysis of MRCP. The use of high-concentration ferric ammonium citrate (Ferriseltz) is recommended to reduce bright signal of fluid-filled gastrointestinal tracts. In case of long breathhold sequences, O2-inhalation study is useful to eliminate respiratory motion artifacts. Careful attention should be paid to the spasm of Oddi's sphincter and the vascular compression of bile ducts to avoid erroneous interpretation of MRCP findings.     

Long-term cure of a malignant lymphoma of the pleural cavity treated by irradiation

Malignant lymphomas arise in the pleura in association with a long-standing chronic tuberculous pyothorax. We report a case of a non-Hodgkin's lymphoma of the pleural cavity, inoperable because of local invasion into thoracic wall, who has survived more than 6 years without recurrence. This patient represents the longest reported survival after radiation therapy alone. Radiotherapy holds an important role in the treatment of locally advanced lymphoma of the pleural cavity.     

Oligoethylenes in high pressure polyethylene

Summary Series of several alkylated cycloheptanes were detected in some commercial samples of high pressure polyethylene. The structures of the alkylated cycloheptanes were found closely related to the chain transfer agents used in the polymerization process. A probable mechanism involving radical cyclization to cycloheptane structures was presented.     

Phase study on solid fission products,Ba, Sr and Zr in oxide fuel

Behavior of pseudo-fission products (Ba, Sr, and Zr) as oxides in UO₂ has been investigated by means of high-temperature X-ray diffraction and microprobe analysis. Two identifiable compounds were formed as reaction products in the mixed oxides which initially consisted of UO₂, BaO, SrO, and ZrO₂ powder. These compounds were present and were identified crystallographically as (Ba, Sr) ZrO₃ and (Ba, Sr)UO₃ after heat treatment of the powders at 1500°C for 30 min. Both compounds are isostructural with perovskite, CaTiO₃, and the lattice parameters of both (Ba, Sr)ZrO₃ and (Ba, Sr)UO₃ decrease with increasing content of Sr. (Ba, Sr)UO₃ is decomposed almost completely at 1800°C while (Ba, Sr) ZrO₃ is stable up to 2000°C. The behavior of Ba, Sr, and Zr in fuel under irradiation is discussed.