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Volume 49 (2022)
- Issue 4 Pages 146-
- Issue 3 Pages 95-
- Issue 2 Pages 55-
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Volume 49, Issue 2
Displaying 1-7 of 7 articles from this issue
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JSCTA Research Encouragement Award 2021
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Masaki Kakiage2022 Volume 49 Issue 2 Pages 55-61
Published: April 25, 2022
Released on J-STAGE: June 20, 2022
JOURNAL FREE ACCESSWe have evaluated the characteristic phase transition and melting behavior derived from the higher-order structure of polymer materials by differential scanning calorimetry (DSC) and in situ X-ray measurements. Furthermore, by combining the results of these thermal measurements with real space observations using an electron microscope, we clarified the correlation between thermal behavior and structure/property in polymer materials. We discussed the phase transition behavior from the orthorhombic phase into the hexagonal phase during heating of melt- drawn ultrahigh-molecular-weight polyethylene (UHMW-PE) samples with different molecular weight characteristics, and revealed that the perfection of the phase transition and the width of the temperature window of the hexagonal phase during heating of melt-drawn UHMW-PE samples depend on their higher-order structure reflecting molecular weight characteristics. The melting behavior of polyethylene/polystyrene diblock copolymer (PE-b-PS) isothermally crystallized at different crystallization temperatures (Tc) was investigated. DSC melting thermograms for PE-b-PS isothermally crystallized at different Tcs were measured, and a deconvolution analysis was performed. The deconvolution analysis of DSC profiles was useful for evaluating the constitution of crystalline domains in the bicontinuous crystalline/amorphous structure of isothermally crystallized PE-b-PS.View full abstractDownload PDF (1323K) -
Satoru Nagatoishi2022 Volume 49 Issue 2 Pages 62-66
Published: April 25, 2022
Released on J-STAGE: June 20, 2022
JOURNAL FREE ACCESSThe use of small-molecule ligands to control biological activities at the molecular level is expected to lead not only to an essential understanding of cellular systems but also to the development of applications in medicine and diagnosis. In the conventional search for small molecule drugs, there is often insufficient information on the mechanism of action at the molecular level for the selected candidate compounds. Therefore, evaluation of the specificity of the candidate drug to the target molecule is an important step. Therefore, we hypothesized that it is crucial to capture the “quality of the interaction” that can create specificity in the binding mode even if the affinity is low, and those thermodynamic indices can capture this quality. Here, we conducted compound selection by thermal measurement using ITC and were able to select compounds with activity against the target protein in vitro and in the cell. This method is expected to create new compounds with specific binding modes that have been overlooked in conventional screening due to their low affinity.View full abstractDownload PDF (1467K)
Review
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Nobuto Yoshinari2022 Volume 49 Issue 2 Pages 67-71
Published: April 25, 2022
Released on J-STAGE: June 20, 2022
JOURNAL FREE ACCESSWhile many superionic conductors for light alkali metal ions (Li+ or Na+) have been developed based on ceramics and metal-organic composite materials, fast ion conduction of larger K+ ions in ambient conditions has long been a challenging target because of the large ionic radius of K+ ion. Recently, our research group reported a unique supramolecular framework of the nanometer-sized spherical metal complex (K-NCIS), which shows excellent K+ conduction of 13 mS/cm at room temperature. Although the presence of many solvated water molecules in the crystals accelerated the K+ conductivity in K-NCIS, the mobility of K+ was not frozen even below 0 ºC owing to the anomalous behavior of water molecules filled in the crystal lattice. The high transport number (t) of K+ for K-NCIS was proven by the NMR spectroscopy and ion-diffusion experiment in the solid-state. An ongoing study on constructing all-solid-state K+ batteries using K-NCIS as solid-electrolyte will also be described.View full abstractDownload PDF (1347K) -
Emiko Okamura2022 Volume 49 Issue 2 Pages 72-78
Published: April 25, 2022
Released on J-STAGE: June 20, 2022
JOURNAL FREE ACCESSDrug delivery from water to lipid bilayer membranes is crucial as a primary step of bioactivities in the cell. To gain insight into molecular mechanisms of drug deliveries, we have developed the method to monitor dynamic properties of drugs and lipid components in membranes, by applying high-resolution solution NMR combined with the pulsed-field-gradient (PFG) technique in a noninvasive manner. The PFG method unveiled the bound component after the preferential decay of the free component at the high field gradient, where the chemical shift difference between these components was not enough to distinguish from each other. Using phospholipid vesicles as model cell membranes, we quantified the diffusivity, the kinetics of membrane binding, and thermodynamic stability of small-sized drugs in relation to the temperature. Cell membrane permeability was also discussed by real-time in-cell NMR spectroscopy in combination with isothermal titration calorimetry of the model system. Finally, the dynamical features in lipid membranes, as platform of drug transport, were characterized by temperature dependence of NMR nuclear overhauser effect (NOE) in cell-sized giant vesicles, to demonstrate large fluctuation of lipids in the vertical direction to the membrane surface related to drug delivery phenomena.View full abstractDownload PDF (1266K) -
Hiroaki Mamiya, Noriki Terada, Ryo Tamura2022 Volume 49 Issue 2 Pages 79-85
Published: April 25, 2022
Released on J-STAGE: June 20, 2022
JOURNAL FREE ACCESSEnergy storage is one of the most important issues for using renewable energy resources. Although liquid hydrogen is expected as a main energy storage carrier, at the present, a gas compression cycle cooling technique for liquefaction of hydrogen requires high operation costs. Magnetic refrigeration using magnetocaloric effects is known as an alternative refrigeration technique. In this review, we introduce the principle of magnetocaloric effects caused by magnetic entropy changes with varying a magnetic field. Next, the features of magnetocaloric effects in paramagnets are outlined as refrigerants for adiabatic demagnetization refrigerator working at very low temperatures. Then we note the characteristics of magnetocaloric effects in ferromagnets as refrigerants for air-conditioner operating at room temperatures. The potential of magnetocaloric effects induced by spin rearrangement transitions in various magnetic materials is considered as refrigerants for hydrogen liquefiers working in the intermediate temperature range. As an example, we describe the highly efficient cooling using pure holmium metal where small magnetic field oscillation superimposed on a static bias magnetic field are applied around its metamagnetic transitions. Finally, we summarize the future prospects of magnetic refrigeration efficiently utilizing magnetocaloric effects.View full abstractDownload PDF (1613K)
Help Keywords
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2022 Volume 49 Issue 2 Pages 86-88
Published: April 25, 2022
Released on J-STAGE: June 20, 2022
JOURNAL FREE ACCESSDownload PDF (373K)
Tutorial
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Yasuo Saruyama2022 Volume 49 Issue 2 Pages 89-90
Published: April 25, 2022
Released on J-STAGE: June 20, 2022
JOURNAL FREE ACCESSDownload PDF (476K)
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