Unusual Two-Step Assembly of a Minimalistic Dipeptide-Based Functional Hypergelator

Self-assembled peptide hydrogels represent the realization of peptide nanotechnology into biomedical products. There is a continuous quest to identify the simplest building blocks and optimize their critical gelation concentration (CGC). Herein, a minimalistic, de novo dipeptide, Fmoc-Lys(Fmoc)-Asp, as an hydrogelator with the lowest CGC ever reported, almost fourfold lower as compared to that of a large hexadecapeptide previously described, is reported. The dipeptide self-assembles through an unusual and unprecedented two-step process as elucidated by solid-state NMR and molecular dynamics simulation. The hydrogel is cytocompatible and supports 2D/3D cell growth. Conductive composite gels composed of Fmoc-Lys(Fmoc)-Asp and a conductive polymer exhibit excellent DNA binding. Fmoc-Lys(Fmoc)-Asp exhibits the lowest CGC and highest mechanical properties when compared to a library of dipeptide analogues, thus validating the uniqueness of the molecular design which confers useful properties for various potential applications.     

Using Turmeric Oil as a Solvent Improves the Distribution of Sesamin-Sesamolin in the Serum and Brain of Mice

Accumulation of amyloid-β peptide is associated with Alzheimer's dementia. Previously, we reported that sesamin and sesamolin inhibited β-secretase activity in vitro, and each was transported to the serum and brain in mice after oral administration. However, the bioavailability of sesamin and sesamolin was poor in mice. In this study, we aimed to improve the bioavailability of sesamin and sesamolin. We found that the levels of sesamin and sesamolin in mouse serum and brain were higher after the administration of a mixture of sesame extract and turmeric oil (MST) than those after administering sesame extract alone. Serum sesamin and sesamolin contents in the MST-treated group were 23-fold and 15-fold higher, respectively, than those in the sesame extract-treated group. Brain sesamin and sesamolin contents in the MST-treated group were 14-fold and 11-fold higher, respectively, than those in the sesame extract-treated group. These results suggest that turmeric oil is an effective solvent to enhance the bioavailability of sesamin and sesamolin.     

Motion control of underactuated linkage robot based on gymnastic skill

In this paper, a reproduction of a swing‐up and a giant swing motion of underactuated robots based on technique of the horizontal bar gymnast is discussed with focusing on an equivalent center of mass (ECM) of underactuated robots and the gymnast. At first, the behaviors of the ECM of the gymnast (ECMG) are analyzed by using a motion capturing technique and an efficient motion of the ECMG for the swing‐up and for the giant swing motion are identified from analysis results, respectively. Next, a partial linearization method, which can realize that the ECM of the Acrobot (ECMA) replicates this efficient motion, is designed and reproduces the underactuated robots the swing‐up and giant swing motion like the gymnast. Finally, an effectiveness of the proposed controller is shown by numerical simulations.     

Contribution of metal vapor mass at periphery part of pulsed arc to electromagnetic force in weld pool

The arc welding has been used in various welding methods because it is inexpensive and high in strength after welding. However, it is a problem that accidents such as collapse of the bridge occur because of the welding defects. The welding of low cost and high productivity is required without the welding defects. The pulsed TIG welding is inexpensive and capable of high‐quality welding. The electromagnetic force contributing to penetration changes because the transient response of arc temperature and iron vapor generated from anode occurs. However, the analysis of pulsed TIG welding with metal vapor has been elucidated only metal vapor concentration near anode with transient phenomenon and heat flux. Thus, the theoretical elucidation of penetration depth with control factor has not been researched. In this paper, the contribution of metal vapor mass at the periphery part of pulsed arc to the electromagnetic force in the weld pool is elucidated. As a result, the iron vapor mass at periphery part decreased with increasing the frequency. The iron vapor was stagnated at axial center within one cycle. The electromagnetic force to the penetration depth direction in weld pool increased at axial center. Therefore, the metal vapor mass at periphery part plays an important role for the electromagnetic force increment at axial center.     

Novel SiC synthesis method applicable to SiC solid phase sintering

Most of the present production processes of SiC sintered bodies require some powder mixing using a mechanical milling process (ball milling, and so on). In this case, relatively long hours are required, and there is the problem of contamination during the preparation process. To avoid these problems, we developed a new process for obtaining a self-sinterable, stoichiometric SiC powder, whose precursor material is water-soluble; the precursor material was synthesized from aqueous silica and citric acid containing a small amount of aluminum compound. In order to obtain the stoichiometric SiC composition, the above aqueous precursor material was adequately cured in air (200°C-400°C); subsequently carbonization reaction (~800°C) in nitrogen atmosphere, carbothermal reduction (~1600°C) in argon atmosphere, and pressureless sintering (~1900°C) were performed. Among these processes, the curing process (cross-linking process) is very important for obtaining the equivalent composition (silica and carbon) for the subsequent carbothermal reduction. In this study, the adequate curing temperature and suitable preparation condition for the carbothermal reduction were investigated for the production of stoichiometric self-sinterable SiC powder. The pressureless sintered body achieved using the obtained SiC powder demonstrated a desirable trans-crystalline fracture behavior.     

Research and development of liquid hydrogen (LH2) temperature monitoring system for marine applications

Monitoring the temperature in liquid hydrogen (LH₂) storage tanks on ships is important for the safety of maritime navigation. In addition, accurate temperature measurement is also required for commercial transactions. Temperature and pressure define the density of liquid hydrogen, which is directly linked to trading interests. In this study, we developed and tested a liquid hydrogen temperature monitoring system that uses platinum resistance sensors with a nominal electrical resistance of approximately 1000 Ω at room temperature, PT-1000, for marine applications. The temperature measurements were carried out using a newly developed temperature monitoring system under different pressure conditions. The measured values are compared with a calibrated reference PT-1000 resistance thermometer. We confirm a measurement accuracy of ±50 mK in a pressure range of 0.1 MPa–0.5 MPa.     

Chromium evaporation and oxidation characteristics of alumina-forming austenitic stainless steels for balance of plant applications in solid oxide fuel cells

The chromium (Cr) evaporation behavior of several different types of iron (Fe)-based AFA alloys and benchmark Cr₂O₃-forming Fe-based 310 and Ni-based 625 alloys was investigated for 500 h exposures at 800 °C to 900 °C in air with 10% H₂O. The Cr evaporation rates from alumina-forming austenitic (AFA) alloys were ~5 to 35 times lower than that of the Cr₂O₃-forming alloys depending on alloy and temperature. The Cr evaporation behavior was correlated with extensive characterization of the chemistry and microstructure of the oxide scales, which also revealed a degree of quartz tube Si contamination during the test. Long-term oxidation kinetics were also assessed at 800 to 1000 °C for up to 10,000 h in air with 10% H₂O to provide further guidance for SOFC BOP component alloy selection.     

Dimeric C34 Derivatives Linked through Disulfide Bridges as New HIV-1 Fusion Inhibitors

C34, a 34-mer fragment peptide, is contained in the HIV-1 envelope protein gp41. A dimeric derivative of C34 linked through a disulfide bridge at its C terminus was synthesized and found to display potent anti-HIV activity, comparable with that of a previously reported PEGylated dimer of C34REG. The reduction in the size of the linker moiety for dimerization was thus successful, and this result might shed some light on the mechanism of the suppression of six-helix bundle formation by these C34 dimeric derivatives. Addition of a Gly-Cys(CH₂CONH₂)-Gly-Gly motif at the N-terminal position of a C34 monomeric derivative significantly increased the anti-HIV-1 activity. This moiety functions as a new pharmacophore, and this might provide a useful insight into the design of potent HIV-1 fusion inhibitors.