Slowing and stopping of chemical waves in a narrowing canal

The propagation of a chemical wave in a narrow, cone-shaped glass capillary was investigated. When a chemical wave propagates from the wider end to the narrower end, it slows, stops, and then disappears. A phenomenological model that considers the surface effect of the glass is proposed, and this model reproduces the experimental trends.Comment: 8 pages, 5 figure

The probability of double-strand breaks in giant DNA decreases markedly as the DNA concentration increases

DNA double-strand breaks (DSBs) represent a serious source of damage for all living things and thus there have been many quantitative studies of DSBs both in vivo and in vitro. Despite this fact, the processes that lead to their production have not yet been clearly understood, and there is no established theory that can account for the statistics of their production, in particular, the number of DSBs per base pair per unit Gy, here denoted by P1, which is the most important parameter for evaluating the degree of risk posed by DSBs. Here, using the single-molecule observation method with giant DNA molecules (166 kbp), we evaluate the number of DSBs caused by gamma-ray irradiation. We find that P1 is nearly inversely proportional to the DNA concentration above a certain threshold DNA concentration. A simple model that accounts for the marked decrease of P1 shows that it is necessary to consider the characteristics of giant DNA molecules as semiflexible polymers to interpret the intrinsic mechanism of DSBs

(1)発光キノコ、ヤコウタケのルシフェリン探索研究 (2)ホタルイカ卵からのルシフェリン単離研究

電気通信大学200

THE DIFFERENCES BETWEEN DOUBLE AND SINGLE LEG TAKEOFF ON JOINT KINETICS DURING REBOUND-TYPE JUMP

The purpose of this study was to identify the differences between double and single leg takeoff on joint kinetics during a rebound-type jump. Twelve male track and field athletes performed repeated rebound-type jumps with double legs (DRJ) and a single leg (SRJ). Kinematics and kinetics data were recorded using a high-speed video camera (300 Hz) and force platforms (1000 Hz). The negative and the positive values of the joint torque power about the ankle joint were significantly lower in DRJ than in SRJ. However, the mean joint extension torque, and the negative value of the joint torque power about the hip joint was larger in SRJ than in DRJ. It is suggested that the joint kinetics characteristics, in SRJ as compared to DRJ, reveals a relatively large joint torque and torque power about the hip joint

Designing Dirac points in two-dimensional lattices

We present a framework to elucidate the existence of accidental contacts of energy bands, particularly those called Dirac points which are the point contacts with linear energy dispersions in their vicinity. A generalized von-Neumann-Wigner theorem we propose here gives the number of constraints on the lattice necessary to have contacts without fine tuning of lattice parameters. By counting this number, one could quest for the candidate of Dirac systems without solving the secular equation. The constraints can be provided by any kinds of symmetry present in the system. The theory also enables the analytical determination of k-point having accidental contact by selectively picking up only the degenerate solution of the secular equation. By using these frameworks, we demonstrate that the Dirac points are feasible in various two-dimensional lattices, e.g. the anisotropic Kagome lattice under inversion symmetry is found to have contacts over the whole lattice parameter space. Spin-dependent cases, such as the spin-density-wave state in LaOFeAs with reflection symmetry, are also dealt with in the present scheme.Comment: 15pages, 9figures (accepted to Phys. Rev. B

Chemo-enzymatic hybrid process for production of monatin, a high intensity sweetener

Monatin, 4-hydroxy-4-(3-indolylmethyl)-glutamic acid, is a naturally occurring sweet amino acid isolated from the plant Sclerochiton ilicifolius, found in South Africa [1]. Monatin has two asymmetric centers at C2 and C4, the (2R,4R)-monatin isomer has been found to be the sweetest among its four stereoisomers. It is 2700 times sweeter than sugar and has a clean taste like sugar. Because of these properties, (2R,4R)-monatin has been expected as an new high-intensity sweetener [2]. However, industrial production process of (2R,4R)-monatin using inexpensive raw materials has not been established owing to the difficulty for optically specific synthesis. Here, we report a chemo-enzymatic hybrid process for production of (2R,4R)-monatin from l-tryptophan. In the steps of enzymatic reaction from l-tryptophan, l-amino acid deaminase and aldolase were used for production of 4-(Indole-3-ylmethyl)-4-hydroxy-2-oxoglutaric acid (IHOG) with pyruvic acid as co-substrate. The keto-form of (2R,4R)-monatin, (R)-IHOG, was specifically synthesized by using R-specific aldolase from Shingomonas sp. in the second reaction. In the next chemical reaction steps, (R)-IHOG was converted to the oxime form, reduced to (2R,4R) and (2S,4R)-monatin, and (2R,4R)-monatin salt was obtained from optical resolution by crystallization. By the combination of epimerization and crystallization, (2R,4R)-monatin was obtained specifically from the mixture of diastereomers. In this study, we established an efficient production process for (2R,4R)-monatin using both chemical and enzymatic reactions, and a large amount of (2R,4R)-monatin was prepared by the bench-scale production. Please click Additional Files below to see the full abstract

THE COMPARISON TO THE CHARACTERISTICS OF THREE-DIMENSIONAL JOINT KINETICS BETWEEN SINGLE LEG AND DOUBLE LEG REBOUND JUMP

The purpose of this study was to clarify the differences between the SRJ and DRJ in terms of three-dimensional joint kinetics for the takeoff leg. Twenty male track and field athletes were performed repeated rebound jump with single leg (SRJ) and double leg (DRJ). Kinematics and kinetics data were recorded using Vicon T20 system (250 Hz) and force platforms (1000 Hz). When comparing a SRJ to a DRJ, the characteristics of the former are as follows: 1) the jump height by a single leg is significantly higher because of the larger hip joint work around the extension-flexion, especially on the abduction-adduction axes; 2) the hip extension and abduction torque is larger; and 3) in the SRJ, the hip abduction torque is larger than the hip extension torque. Therefore, the joint kinetics of the SRJ is characterized by the large hip abduction torque, in addition to the large hip extension torque

Quality Control Oriented to the Product Liability Problem

藤田彰久教授古稀記念特

A case of generalized lymphatic anomaly causing skull-base leakage and bacterial meningitis

Generalized lymphatic anomaly (GLA) is a multifocal lymphatic malformation that affects the skin, thoracic viscera, and bones. A 7-year-old boy presented with fever and disturbance of consciousness, and bacterial meningitis was diagnosed. Computed tomography and magnetic resonance imaging revealed middle skull-base leakage due to lymphatic malformation. Past history included facial palsy due to cystic tumors in the right petrous bone 4 years before onset of meningitis. At that time, pericardial effusion had been found and GLA had been diagnosed by pericardial biopsy. He achieved complete recovery under intensive care with antibiotics and mechanical ventilation. At the 3-year follow-up, the patient was healthy with no recurrence of meningitis. We should consider GLA among the differential diagnoses for osteolytic diseases in the pediatric population