Structural Insights into the Epimerization of β-1,4-Linked Oligosaccharides Catalyzed by Cellobiose 2-Epimerase, the Sole Enzyme Epimerizing Non-anomeric Hydroxyl Groups of Unmodified Sugars

Cellobiose 2-epimerase (CE) reversibly converts d-glucose residues into d-mannose residues at the reducing end of unmodified β1,4-linked oligosaccharides, including β-1,4-mannobiose, cellobiose, and lactose. CE is responsible for conversion of β1,4-mannobiose to 4-O-β-d-mannosyl-d-glucose in mannan metabolism. However, the detailed catalytic mechanism of CE is unclear due to the lack of structural data in complex with ligands. We determined the crystal structures of halothermophile Rhodothermus marinus CE (RmCE) in complex with substrates/products or intermediate analogs, and its apo form. The structures in complex with the substrates/products indicated that the residues in the β5-β6 loop as well as those in the inner six helices form the catalytic site. Trp-322 and Trp-385 interact with reducing and non-reducing end parts of these ligands, respectively, by stacking interactions. The architecture of the catalytic site also provided insights into the mechanism of reversible epimerization. His-259 abstracts the H2 proton of the d-mannose residue at the reducing end, and consistently forms the cis-enediol intermediate by facilitated depolarization of the 2-OH group mediated by hydrogen bonding interaction with His-200. His-390 subsequently donates the proton to the C2 atom of the intermediate to form a d-glucose residue. The reverse reaction is mediated by these three histidines with the inverse roles of acid/base catalysts. The conformation of cellobiitol demonstrated that the deprotonation/reprotonation step is coupled with rotation of the C2-C3 bond of the open form of the ligand. Moreover, it is postulated that His-390 is closely related to ring opening/closure by transferring a proton between the O5 and O1 atoms of the ligand

Urban spatial structures from human flow by Hodge-Kodaira decomposition

Human flow in cities indicates social activity and can reveal urban spatial structures based on human behaviours for relevant applications. Scalar potential is a mathematical concept, and if successfully introduced, it can provide an intuitive perspective of human flow. However, the definition of such a potential to the origin-destination flow matrix and determination of its plausibility remain unsolved. Here, we apply Hodge-Kodaira decomposition, in which a matrix is uniquely decomposed into a potential-driven (gradient) flow and a curl flow. We depict the potential landscapes in cities due to commuting flow and reveal how the landscapes have been changed or unchanged by years or transport methods. We then determine how well the commuting flow is described by the potential, by evaluating the percentage of the gradient component for metropolitan areas in the USA and show that the gradient component is almost 100\% in several areas; in other areas, however, the curl component is dominant, indicating the importance of circular flow along triangles of places. The potential landscape provides an easy-to-use visualisation tool to show the attractive places of human flow and will aid in various applications in commerce, urban design, and epidemic spreading

「解説・説明」を中心とする時事問題学習の意義と課題 : 高校・国際コース特別科目「国際理解」 (Global Studies) をふりかえって

　I indicated the significance of and problems concerning \u27comments and explanation\u27 centered lesson units on current issues through analyzing the lesson unit in the subject of \u27Global Studies\u27 that I created and implemented in the high school where I formerly fought.　The significance of that practice is that a high school teacher could create and implement the lesson unit on \u27current issues\u27 about the decline of the USSR and East European nations by using a lot of materials from the news media, i.e. TV programs and newspapers. And also it is that I could illustrate the typical lesson unit oriented toward \u27comment and explanation\u27 by the teacher.　The problems are two fold. First it cost me hard work and much time to create the teaching lessons and materials, Second, as a high school teacher with other work I could not help presenting, or even indoctrinating students with my viewpoints on current issues, alongside the news media.　I suggested two ways to solve these problems and improve these lessons,: learning to acquire concepts and learning to think critically about the news media.論文 (Article

Dynamic Finite Element Analysis of Impulsive Stress Waves Propagating from Distal End of Femur

The human femur is subjected to an impulsive load at its distal end during daily life. Femoral bone fracture caused by impact loading is common in elderly women. It is important to clarify the dynamic response of the femur and to evaluate the change in its stress state during impact loading. A 3-dimensional model of the femur was prepared in the present study, and the impulsive stress waves propagating from the distal end of the femur were analyzed by the dynamic finite element method. This model showed that the von Mises equivalent stress is large on the anterior and posterior sides of the mid-diaphysis when the impact direction is different from that of the bone axis. As for the femoral neck, the absolute value of minimum principal stress initially increases on the medial side;slightly later the maximum principal stress increases on the lateral side. In this case, the absolute value of the maximum principal stress was found to be larger than that of the minimum principal stress, and the absolute value of the principal stress decreased as the impact angle increased. Further, the femoral neck and the trochanter were shown to have a higher risk of bone fracture when the impact direction is coincident with the bone axis

Current issues studies introduced in media literacy and development education in the U.K. : a case study of the "global express" as the development education project

Global Express aims to enable young people to gain a greater understanding of the context in which news stories from the developing world happen and to build links between their experience of life and their understanding of development issues. (Global Express site, http : //www.dep.org.uk/globalexpress/) The contents of this research consist of three parts : (1) identifying what is the Global Express, (2) anlysing what a kind of topics it has and what is standards of decision-making for Global Express topics among every edition from 1st to 42nd, and, (3) examining the possibility of critical thinking based Current Issues Studies through the case study of the 34th edition of Global Express about Iraq War 2002.論文 (Article

The significance of current issues studies and the strategy of developing learning units in social studies

　The contents of this research consist of two parts: identifying the significance of current issues studies through the analysis of \u27Social Studies in Japan in the early years after the Second World War.\u27 and N.I.E; Newspapers in Education; and clarifying the strategy of developing learning units in social studies in order to improve the lesson plans for current issues studies.　Current issues are \u27the controversial issues in our society and the world\u27. Therefore the aims of learning current issues are to make students become involved in their society and to have them examine consider the values of a democratic society by themselves.　Also I present the principles of a learning methodology for social studies related to a democratic society, and then, I apply them to the analysis of learning units for current issues in recent years, and propose an improved design for them.論文 (Article

The possibility of citizenship education in schools in Japan : an analysis of experimental implementations

　Recently a proposal and some implementations about citizenship education have been tried in Japan with response to the UK. They are the report of citizenship education by a research group sponsored by the Ministry of Economy, Trade and Industry, the attached Ikeda Junior High School of Osaka University of Education, primary and Junior high schools governed by the local authority of Shinagawa-Ku, Tokyo, and the attached primary school of Ochanomizu University.　This research analyses those implementations and curricula from the perspective of subject education and research, and indicates some viewpoints on citizenship education in schools.　The contents of this research consist of four parts: (1) examining citizenship at the national level and competency of citizens in contemporary society, (2) analyzing implementations and curricula at the attached Ikeda Junior High School, the local authority of Shinagawa-Ku and the attached primary school of Ochanomizu, (3) indicating some viewpoints on citizenship education in Japan compared with the UK, (4) proposing citizenship studies as comprehensive social studies in schools.論文 (Article

Optimization temperature sensitivity using the optically detected magnetic resonance spectrum of a nitrogen-vacancy center ensemble

Temperature sensing with nitrogen vacancy (NV) centers using quantum techniques is very promising and further development is expected. Recently, the optically detected magnetic resonance (ODMR) spectrum of a high-density ensemble of the NV centers was reproduced with noise parameters [inhomogeneous magnetic field, inhomogeneous strain (electric field) distribution, and homogeneous broadening] of the NV center ensemble. In this study, we use ODMR to estimate the noise parameters of the NV centers in several diamonds. These parameters strongly depend on the spin concentration. This knowledge is then applied to theoretically predict the temperature sensitivity. Using the diffraction-limited volume of 0.1 micron^3, which is the typical limit in confocal microscopy, the optimal sensitivity is estimated to be around 0.76 mK/Hz^(1/2) with an NV center concentration of 5.0e10^17/cm^3. This sensitivity is much higher than previously reported sensitivities, demonstrating the excellent potential of temperature sensing with NV centers.Comment: 17 pages, 4 figures, 1 tabl

Oral environment and cancer

Cancer is now the leading cause of death in Japan. A rapid increase in cancer mortality is expected as Japan is facing a super-aged society. Many causes of cancer are known to be closely linked to life style factors, such as smoking, drinking, and diet. The oral environment is known to be involved in the pathogenesis and development of various diseases such as bronchitis, pneumonia, diabetes, heart disease, and dementia. Because the oral cavity acts as the bodily entrance for air and food, it is constantly exposed to foreign substances, including bacteria and viruses. A large number of bacteria are endemic to the oral cavity, and indigenous oral flora act to prevent the settlement of foreign bacteria. The oral environment is influenced by local factors, including dental plaque, tartar, teeth alignment, occlusion, an incompatible prosthesis, and bad lifestyle habits, and systemic factors, including smoking, consumption of alcohol, irregular lifestyle and eating habits, obesity, stress, hormones, and heredity. It has recently been revealed that the oral environment is associated with cancer. In particular, commensal bacteria in the oral cavity are involved in the development of cancer. Moreover, Candida, human papilloma virus and Epstein-Barr virus as well as commensal bacteria have been reported to be associated with the pathogenesis of cancer. In this review, we introduce recent findings of the correlation between the oral environment and cancer

Fractional anisotropy in the centrum semiovale as a quantitative indicator of cerebral white matter damage in the subacute phase in patients with carbon monoxide poisoning: correlation with the concentration of myelin basic protein in cerebrospinal fluid

Carbon monoxide (CO) poisoning leads to demyelination of cerebral white matter (CWM) fibers, causing chronic neuropsychiatric symptoms. To clarify whether fractional anisotropy (FA) from diffusion tensor imaging in the centrum semiovale can depict demyelination in the CWM during the subacute phase after CO inhalation, we examined correlations between FA in the centrum semiovale and myelin basic protein (MBP) in cerebrospinal fluid. Subjects comprised 26 adult CO-poisoned patients ≤60 years old. MBP concentration was examined for all patients at 2 weeks after CO inhalation. The mean FA of the centrum semiovale bilaterally at 2 weeks was also examined for all patients and 21 age-matched healthy volunteers as controls. After these examinations, the presence of chronic symptoms was checked at 6 weeks after CO poisoning. Seven patients displayed chronic symptoms, of whom six showed abnormal MBP concentrations. The remaining 19 patients presented no chronic symptoms and no abnormal MBP concentrations, with MBP concentrations undetectable in 16 patients. The MBP concentration differed significantly between patients with and without chronic symptoms. The mean FA was significantly lower in patients displaying chronic symptoms than in either patients without chronic symptoms or controls. After excluding the 16 patients with undetectable MBP concentrations, a significant correlation was identified between MBP concentration and FA in ten patients. The present results suggest that FA in the centrum semiovale offers a quantitative indicator of the extent of demyelination in damaged CWM during the subacute phase in CO-poisoned patients