On the six-field model of fluids based on extended thermodynamics

We study the six-field model of fluids (ET6) derived from extended thermodynamics. The six fields are the mass density, the velocity, the temperature, and the dynamic pressure (nonequilibrium pressure). We present the basic system of field equations of ET6. And we elucidate its characteristic features through the studies of the singular limit from polyatomic to monatomic rarefied gases, of hydrodynamic fluctuation, and of a hard-sphere system. Open problems remained in ET6 at present are also pointed out.     

The Electronic State of Hydrogen in the α Phase of the Hydrogen‐Storage Material PdH(D)x: Does a Chemical Bond Between Palladium and Hydrogen Exist?

The palladium–hydrogen system is one of the most famous hydrogen‐storage systems. Although there has been much research on β‐phase PdH(D)_x, we comprehensively investigated the nature of the interaction between Pd and H(D) in α‐phase PdH(D)_x (x<0.03 at 303 K), and revealed the existence of Pd?H(D) chemical bond for the first time, by various in situ experimental techniques and first‐principles theoretical calculations. The lattice expansion, magnetic susceptibility, and electrical resistivity all provide evidence. In situ solid‐state ¹H and ²H NMR spectroscopy and first‐principles theoretical calculations revealed that a Pd?H(D) chemical bond exists in the α phase, but the bonding character of the Pd?H(D) bond in the α phase is quite different from that in the β phase; the nature of the Pd?H(D) bond in the α phase is a localized covalent bond whereas that in the β phase is a metallic bond.     

DNA Origami Scaffolds as Templates for Functional Tetrameric Kir3 K+ Channels

In native systems, scaffolding proteins play important roles in assembling proteins into complexes to transduce signals. This concept is yet to be applied to the assembly of functional transmembrane protein complexes in artificial systems. To address this issue, DNA origami has the potential to serve as scaffolds that arrange proteins at specific positions in complexes. Herein, we report that Kir3 K⁺ channel proteins are assembled through zinc‐finger protein (ZFP)‐adaptors at specific locations on DNA origami scaffolds. Specific binding of the ZFP‐fused Kir3 channels and ZFP‐based adaptors on DNA origami were confirmed by atomic force microscopy and gel electrophoresis. Furthermore, the DNA origami with ZFP binding sites nearly tripled the K⁺ channel current activity elicited by heterotetrameric Kir3 channels in HEK293T cells. Thus, our method provides a useful template to control the oligomerization states of membrane protein complexes in vitro and in living cells.     

Removal and regeneration of aqueous divalent cations by boehmite

Boehmite (Al(OH)O) was employed for the removal of aqueous Mg(2+), Cu(2+), Cd(2+), Pb(2+), and Co(2+) at 298 K. Although boehmite was able to remove these divalent cations, the greater removal rate with boehmite of Pb(2+) (28.7%) than with Mg(2+), Cu(2+), Cd(2+), and Co(2+) (5.6, 25.3, 10.9, and 13.3%, respectively) was observed under acidic conditions. Under stronger alkaline conditions, in which the lead species was completely dissolved, a greater removal rate of Pb(2+) (more than 80%) was observed under the corresponding conditions employed for the acidic conditions. The removed lead species could not be dissolved from boehmite in an acidic solution while an evident dissolution of lead species was detected using an aqueous NaOH solution. The results shown in the present study reveal that boehmite can be employed as a reagent for the removal and regeneration of aqueous metal cations.     

Development of pyrrole-imidazole polyamide for specific regulation of human aurora kinase-A and -B gene expression

Pyrrole-imidazole polyamide (PIP) is a nuclease-resistant novel compound that inhibits gene expression through binding to the minor groove of DNA. Human aurora kinase-A (AURKA) and -B (AURKB) are important regulators in mitosis during the cell cycle. In this study, two specific PIPs (PIP-A and PIP-B) targeting AURKA and AURKB promoter regions were designed and synthesized, and their biological effects were investigated by several in vitro assays. PIP-A and PIP-B significantly inhibited the promoter activities, mRNA expression, and protein levels of AURKA and AURKB, respectively, in a concentration-dependent manner. Moreover, 1:1 combination treatment with both PIPs demonstrated prominent antiproliferative synergy (CI value [ED(50)] = 0.256) to HeLa cells as a result of inducing apoptosis-mediated severe catastrophe of cell-cycle progression. The novel synthesized PIP-A and PIP-B are potent and specific gene-silencing agents for AURKA and AURKB.     

Nanomechanical properties of reversed surfactant bilayers formed in micrometre-sized holes

Nanomechanical properties of free-standing reversed surfactant bilayers, dried foam films (DFFs), were examined via AFM by fitting local force-indentation curves with a Hertzian model. The Young's moduli of four kinds of bilayers were in a range of 10-30 MPa.     

Accessibility and size of <Emphasis Type="Italic">Valonia</Emphasis> cellulose microfibril studied by combined deuteration/rehydrogenation and FTIR technique

We report an FTIR method to measure the accessibility and the size of cellulose microfibrils from the cell wall of Valonia ventricosa. This method is similar to the conventional deuteration technique for measuring the accessibility of cellulosic materials; however, the difference in our method is that the hydroxyl groups O2H, O3H, and O6H in the crystalline region were initially completely deuterated. The sample was then rehydrogenated by soaking in water at 25 °C, so that the OD groups on the surface were rehydrogenated. The ratio of OH to OD absorbance was used to calculate the number of surface vs. core cellulose chains in a microfibril. The obtained experimental ratio of 0.934 was consistent with the value calculated for a previously published 33 × 38 chain Valonia model (Sugiyama et al. 1984). The rehydrogenation process was further investigated by immersing the sample in water at elevated temperatures. At temperatures above 120 °C, rehydrogenation was more efficient, and the efficiency plots vs. rehydrogenation temperature showed two inflection. These points may correspond to the temperature where the cleavage of inter-chain hydrogen bonds and/or crystalline-phase transition would have been occurred.     

Oxidative Annulation of Arenecarboxylic and Acrylic Acids with Alkynes under Ambient Conditions Catalyzed by an Electron‐Deficient Rhodium(III) Complex

It has been established that an electron‐deficient Cp^E rhodium(III) complex catalyzes the oxidative [4+2] annulation of substituted arenecarboxylic and acrylic acids with alkynes under ambient conditions (at RT–40 °C, under air) without using excess amounts of substrates to produce the corresponding substituted isocoumarins and α‐pyrones in high yields. Minor modification of reaction conditions depending on the coordination ability of alkynes realized the high efficiency.     

A new high‐pressure strontium germanate,SrGe2O5

The Sr–Ge–O system has an earth‐scientific importance as a potentially good low‐pressure analog of the Ca–Si–O system, one of the major components in the constituent minerals of the Earth's crust and mantle. However, it is one of the germanate systems that has not yet been fully examined in the phase relations and structural properties. The recent findings that the SrGeO₃ high‐pressure perovskite phase is the first Ge‐based transparent electronic conductor make the Sr–Ge–O system interesting in the field of materials science. In the present study, we have revealed the existence of a new high‐pressure strontium germanate, SrGe₂O₅. Single crystals of this compound crystallized as a co‐existent phase with SrGeO₃ perovskite single crystals in the sample recovered in the compression experiment of SrGeO₃ pseudowollastonite conducted at 6 GPa and 1223 K. The crystal structure consists of germanium–oxygen framework layers stacked along [001], with Sr atoms located at the 12‐coordinated cuboctahedral site; the layers are formed by the corner linkages between GeO₆ octahedra and between GeO₆ octahedra and GeO₄ tetrahedra. The present SrGe₂O₅ is thus isostructural with the high‐pressure phases of SrSi₂O₅ and BaGe₂O₅. Comparison of these three compounds leads to the conclusion that the structural responses of the GeO₆ and GeO₄ polyhedra to cation substitution at the Sr site are much less than that of the SrO₁₂ cuboctahedron to cation substitution at the Ge sites. Such a difference in the structural response is closely related to the bonding nature.