Search

The electrochemical switching of SrCoOx-based non-volatile memory with a thin-film-transistor structure was examined by using liquid-leakage-free electrolytes with different conductivities (σ) as the gate insulator. We first examined leakage-free water, which is incorporated in the amorphous (a-) 12CaO·7Al2O3 film with a nanoporous structure (Calcium Aluminate with Nanopore), but the electrochemical oxidation/reduction of the SrCoOx layer required the application of a high gate voltage (Vg) up to 20V for a very long current-flowing-time (t) ~40min, primarily due to the low σ [2.0 x 10-8S cm-1 at room temperature (RT)] of leakage-free water. We then controlled the r of the leakage-free electrolyte, infiltrated in the a-NaxTaO3 film with a nanopillar array structure, from 8.0 x 10-8S cm-1 to 2.5 x 10-6S cm-1 at RT by changing the x = 0.01–1.0. As the result, the t, required for the metallization of the SrCoOx layer under small Vg = –3V, becomes two orders of magnitude shorter with increase of the σ of the a-NaxTaO3 leakage-free electrolyte. These results indicate that the ion migration in the leakage-free electrolyte is the rate-determining step for the electrochemical switching, compared to the other electrochemical process, and the high σ of the leakage-free electrolyte is the key factor for the development of the non-volatile SrCoOx-based electro-magnetic phase switching device. [ABSTRACT FROM AUTHOR]

Parasitic plants infect other plants by forming haustoria, specialized multicellular organs consisting of several cell types, each of which has unique morphological features and physiological roles associated with parasitism. Understanding the spatial organization of cell types is, therefore, of great importance in elucidating the functions of haustoria. Here, we report a three-dimensional (3-D) reconstruction of haustoria from two Orobanchaceae species, the obligate parasite Striga hermonthica infecting rice (Oryza sativa) and the facultative parasite Phtheirospermum japonicum infecting Arabidopsis (Arabidopsis thaliana). In addition, field-emission scanning electron microscopy observation revealed the presence of various cell types in haustoria. Our images reveal the spatial arrangements of multiple cell types inside haustoria and their interaction with host roots. The 3-D internal structures of haustoria highlight differences between the two parasites, particularly at the xylem connection site with the host. Our study provides cellular and structural insights into haustoria of S. hermonthica and P. japonicum and lays the foundation for understanding haustorium function. [ABSTRACT FROM AUTHOR]

Self-assembled supramolecular structures in living cells and their dynamics underlie various cellular events, such as endocytosis, cell migration, intracellular transport, cell metabolism, and gene expression. Spatiotemporally regulated association/dissociation and generation/degradation of assembly components is one of the remarkable features of biological systems. The significant advancement in DNA nanotechnology over the last few decades has enabled the construction of various-shaped nanostructures via programmed selfassembly of sequence-designed oligonucleotides. These nanostructures can further be assembled into micrometer-sized structures, including ordered lattices, tubular structures, macromolecular droplets, and hydrogels. In addition to being a structural material, DNA is adopted to construct artificial molecular circuits capable of activating/inactivating or producing/decomposing target DNA molecules based on strand displacement or enzymatic reactions. In this review, we provide an overview of recent studies on artificially designed DNA-based self-assembled systems that exhibit dynamic features, such as association/dissociation of components, phase separation, stimulus responsivity, and DNA circuit-regulated structural formation. These biomacromolecule-based, bottom-up approaches for the construction of artificial molecular systems will not only throw light on bio-inspired nano/micro engineering, but also enable us to gain insights into how autonomy and adaptability of living systems can be realized. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the prevalence and genetic characteristics of carbapenemase-producing Enterobacteriaceae (CPE) in hospital sewage and river water in the Philippines, which has a typical tropical maritime climate. We collected 83 water samples from 7 hospital sewage and 10 river water sites. CPE were identified using CHROMagar mSuperCARBA, and Gram-negative strains were identified using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) or 16S rRNA gene sequencing. Resistance genes in Enterobacteriaceae strains were identified using PCR and DNA sequencing, and transferability of carbapenemase genes from the CPE was investigated with conjugation experiments. Genotyping was performed using multilocus sequence typing (MLST) for Escherichia coli and Klebsiella pneumoniae. Out of 124 Enterobacteriaceae isolates, we identified 51 strains as CPE and divided these into 7 species, 11 E. coli, 14 Klebsiella spp., 15 Enterobacter spp., and 11 others, including 4 additional species. Conjugation experiments via broth mating and using E. coli J53 revealed that 24 isolates can transfer carbapenemase-encoding plasmids. MLST analysis showed that 6 of 11 E. coli isolates belonged to clonal complex 10 (CC10). Of 11 K. pneumoniae strains, 9 unique sequence types (STs) were identified, including ST147. Five types of carbapenemase genes were identified, with the most prevalent being NDM (n =39), which is epidemic in clinical settings in the Philippines. E. coli CC10 and K. pneumoniae ST147, which are often detected in clinical settings, were the dominant strains. In summary, our results indicate that hospital sewage and river water are contaminated by CPE strains belonging to clinically important clonal groups. [ABSTRACT FROM AUTHOR]

We discuss relationships among the existence property, the disjunction property, and their weak variants in the setting of intermediate predicate logics. We deal with the weak and sentential existence properties, and the Z-normality, which is a weak variant of the disjunction property. These weak variants were presented in the author's previous paper [16]. In the present paper, the Kripke sheaf semantics is used. [ABSTRACT FROM AUTHOR]

The effective magneto-optical properties of novel nonanuclear Tb(III) complexes with Tb-O lattice (specifically, [Tb9(sal-R)16(μ-OH)10]+NO3-, where sal-R = alkyl salicylate (R = -CH3 (Me), -C2H5 (Et), -C3H7 (Pr), or -C4H9 (Bu)) are reported. The geometrical structures of these nonanuclear Tb(III) complexes were characterized using X-ray single-crystal analysis and shape-measure calculation. Optical Faraday rotation was observed in nonanuclear Tb(III) complexes in the visible region. The Verdet constant per Tb(III) ion of the Tb9(sal-Me) complex is 150 times larger than that of general Tb(III) oxide glass. To understand their large Faraday rotation, electron paramagnetic resonance measurements of Gd(III) complexes were carried out. In this Report, the magneto-optical relation to the coordination geometry of Tb ions is discussed. [ABSTRACT FROM AUTHOR]

Double-strand break repair involves the formation of Holliday junction (HJ) structures that need to be resolved to promote correct replication and chromosomal segregation. The molecular mechanisms of HJ branch migration and/or resolution are poorly characterized in Firmicutes. Genetic evidence suggested that the absence of the RuvAB branch migration translocase and the RecU HJ resolvase is synthetically lethal in Bacillus subtilis, whereas a recU recG mutant was viable. In vitro RecU, which is restricted to bacteria of the Firmicutes phylum, binds HJs with high affinity. In this work we found that RecU does not bind simultaneously with RecG to a HJ. RuvB by interacting with RecU bound to the central region of HJ DNA, loses its nonspecific association with DNA, and re-localizes with RecU to form a ternary complex. RecU cannot stimulate the ATPase or branch migration activity of RuvB. The presence of RuvB•ATγS greatly stimulates RecU-mediated HJ resolution, but the addition of ATP or RuvA abolishes this stimulatory effect. A RecU•HJ•RuvAB complex might be formed. RecU does not increase the RuvAB activities but slightly inhibits them. [ABSTRACT FROM AUTHOR]

Here, we report the direct visualization of the assembly/disassembly processes of photoresponsive DNA origami nanostructures which can be placed on a lipid bilayer surface. The observation relies on controlled interactions between the bilayer components and cholesterol moieties introduced to the hexagonal origami structures, one of whose outer edges carries Azo-ODNs. The bilayer-placed hexagonal dimer was disassembled into monomer units by UV irradiation, and reversibly assembled again during visible light irradiation. These dynamic processes were directly monitored with high-speed atomic force microscopy. The successful application of our approach should facilitate studies of interactive and functional behaviors of various DNA nanostructures. [ABSTRACT FROM AUTHOR]

Site-specific recombination involves reciprocal exchange between defined DNA sites. The reaction initiates from the formation of a recombinase-DNA synaptic complex, in which two recombination sites arrange in an appropriate configuration. However, there is incomplete information about how the topological state of the substrate influences the synapsis and outcome of the reaction. Here, we show that Cremediated recombination can be regulated by controlling the orientation and topology of the loxP substrate in a DNA frame nanoscaffold. High-speed atomic force microscopy analyses revealed that the loxP-containing substrate strands in the antiparallel orientation can be recombined only through formation of synaptic complexes. By tethering Holliday junction (HJ) intermediates to DNA frames in different connection patterns and using them as a starting substrate, we found that the topological state of the HJ intermediates dictates the outcome of the resolution. Our approach should provide a new platform for structural-functional studies of various DNA targeting enzymes, especially which require formation of synaptic complexes. [ABSTRACT FROM AUTHOR]

A hybrid atomic force microscopy (AFM)-optical fluorescence microscopy is a powerful tool for investigating cellular morphologies and events. However, the slow data acquisition rates of the conventional AFMunit of the hybrid system limit the visualization of structural changes during cellular events. Therefore, high-speed AFM units equipped with an optical/fluorescence detection device have been a long-standing wish. Here we describe the implementation of high-speed AFM coupled with an optical fluorescence microscope. This was accomplished by developing a tip-scanning system, instead of a sample-scanning system, which operates on an inverted optical microscope. This novel device enabled the acquisition of high-speed AFM images of morphological changes in individual cells. Using this instrument, we conducted structural studies of living HeLa and 3T3 fibroblast cell surfaces. The improved time resolution allowed us to image dynamic cellular events. [ABSTRACT FROM AUTHOR]

A new class of oligothienoquinoidal derivatives with newly employed (acyl)cyanomethylene termini are reported. For the synthesis of (acyl)cyanomethylene-substituted thienoquinoidals, similar methods successfully employed for the synthesis of related dicyanomethylene- or ((alkyloxy)carbonyl)cyanomethylene-substituted thienoquinoidals were not applicable, and thus a new synthetic route was developed. The introduced (acyl)cyanomethylene terminal groups act both as a solublizing group to facilitate solution processability and an electron-withdrawing group to keep the LUMO energy levels sufficiently low for n-channel organic semiconductors. The LUMO energy levels estimated from their reduction potential are ∼4.2 eV below the vacuum level, which just falls in between those for the corresponding dicyanomethylene- and ((alkyloxy)carbonyl)cyanomethylene-substituted thienoquinoidals. This qualitatively agrees with the electron-withdrawing nature of the terminal groups; the order of the electron withdrawing nature is cyano- > acyl- > (alkyloxy)carbonyl- groups. Spin-coating chloroform solutions of (acyl)cyanomethylene-substituted thienoquinoidals gave homogeneous thin films on the Si/SiO2substrates, and the thin films based on the terthienoquinoidal derivatives became highly crystalline upon thermal annealing. The annealed film acted as the active semiconducting channel in the FET devices under ambient conditions, and the electron mobilities extracted from the saturation regime were ∼0.06 cm2V−1s−1. These n-channel FET characteristics are nearly the same or slightly better than those of the FETs based on the related ((alkyloxy)carbonyl)cyanomethylene-terminated terthienoquinoidal, indicating that the (acyl)cyanomethylene moiety is a useful terminal group on the thienoquinoidals for the development of soluble n-channel organic semiconductors. [ABSTRACT FROM AUTHOR]

Abstract??We experimentally studied the dacitic magma ejected during the first event in the Usu 2000 eruption to investigate the conditions of syneruptive magmatic ascent. Geophysical data revealed that the magma reached under West Nishiyama, the location of the event?s craters, after rising beneath the summit. Prior study of bubble-size distributions of ejecta shows two stages (stage 1 and stage 2) with different magma ascent rates, as the magma accelerated beneath West Nishiyama with the start of the second stage. To simulate ascent of stage 1 from the main reservoir, which was located at a depth of 4?6?km (125?MPa) to 2?km (50?MPa) beneath West Nishiyama, decompression experiments were conducted isothermally at 900?C following two paths. Single step decompression (SSD) samples were decompressed rapidly (0.67?MPa/s) to their final pressure and held for 12 to 144?hours. Multiple step decompression (MSD) samples were decompressed stepwise to their final pressure and quenched instantly. In MSD, the average decompression rates and total experimental durations varied between 0.01389 to 0.00015?MPa/s and 1.5 to 144?hours, respectively. Syneruptive crystallization was confined to stage 1, and the conditions of ascent were determined by documenting similarities in decompression-induced crystallization between ejecta and experiments. Core compositions, number densities, and shapes of experimental microlites indicate that ascent to 2?km depth occurred in less than 1.5?h. Volumes and number densities of experimental microlites from the SSD experiments that best replicate the decompression rate to 2?km indicate that the magma remained at 2?km for approximately 24?h before the eruption. Stagnation at a depth of 2?km corresponds with horizontal transport through a dike from beneath the summit to West Nishiyama, according to geodetic results. The total magma transport timescale including stage 2 is tens of hours and is shorter than the timescale of precursory seismicity (3.5?days), indicating that the erupted magma did not move out of the reservoir for the first 2?days. This is consistent with the temporal change in numbers of earthquakes, which reached a peak after 2?days. [ABSTRACT FROM AUTHOR]

We present a new method of deriving the geometry of entanglement wedges in holography directly from conformal field theories (CFTs). We analyze an information metric called the Bures metric of reduced density matrices for locally excited states. This measures the distinguishability of states with different points excited. For a subsystem given by an interval, we precisely reproduce the expected entanglement wedge for two-dimensional holographic CFTs from the Bures metric, which turns out to be proportional to the anti-de Sitter metric on a time slice. On the other hand, for free scalar CFTs, we do not find any sharp structures like entanglement wedges. When a subsystem consists of two disconnected intervals, we manage to reproduce the expected entanglement wedge from holographic CFTs with the correct phase transitions, up to a very small error, from a quantity alternative to the Bures metric. [ABSTRACT FROM AUTHOR]

RNA is a biopolymer that is attractive for constructing nano-scale objects with complex structures. Threedimensional (3D) structures of naturally occurring RNAs often have modular architectures. The 3D structure of a group I (GI) ribozyme from Tetrahymena has a typical modular architecture, which can be separated into two structural modules ("P5 and P5abc). The fully active ribozyme can be reconstructed by assembling the two separately prepared modules through highly specific and strong assembly between "P5 ribozyme and P5abc RNA. Such non-covalent assembly of the two modules allows the design of polygonal RNA nano-structures. Through rational redesign of the parent GI ribozyme, we constructed variant GI ribozymes as unit RNAs for polygonal-shaped (closed) oligomers with catalytic activity. Programmed trimerization and tetramerization of the unit RNAs afforded catalytically active nano-sized RNA triangles and squares, the structures of which were directly observed by atomic force microscopy (AFM). [ABSTRACT FROM AUTHOR]

The latest eruption of Haruna volcano at Futatsudake took place in the middle of the sixth century, starting with a Plinian fall, followed by pyroclastic flows, and ending with lava dome formation. Gray pumices found in the first Plinian phase (lower fall) and the dome lavas are the products of mixing between felsic (andesitic) magma having 50 vol. % phenocrysts and mafic magma. The mafic magma was aphyric in the initial phase, whereas it was relatively phyric during the final phase. The aphyric magma is chemically equivalent to the melt part of the phyric mafic magma and probably resulted from the separation of phenocrysts at their storage depth of ∼15 km. The major part of the felsic magma erupted as white pumice, without mixing and heating prior to the eruption, after the mixed magma (gray pumice) and heated felsic magma (white pumice) of the lower fall deposit. Although the mafic magma was injected into the felsic magma reservoir (at ∼7 km depth), part of the product (lower fall ejecta) preceded eruption of the felsic reservoir magma, as a consequence of upward dragging by the convecting reservoir of felsic magma. The mafic magma injection made the nearly rigid felsic magma erupt, letting low-viscosity mixed and heated magmas open the conduit and vent. Indeed the lower fall white pumices preserve a record of syneruptive slow ascent of magma to 2 km depth, probably associated with conduit formation. [ABSTRACT FROM AUTHOR]

Simeprevir (SMV), asunaprevir (ASV), daclatasvir (DCV) and sofosbuvir (SOF), which are direct-acting antiviral (DAA) agents, are expected to become essential pharmaceutical tools in the fight against the hepatitis C virus (HCV). However, because DAAs are taken orally, there is a potential risk of drug-drug interactions (DDIs) at the absorption step with co-administered drugs in the small intestine. Since it is known that organic anion transporting polypeptide 2B1 (OATP2B1) is one of the key transporters contributing to intestinal drug absorption, it is important to thoroughly understand the inhibition profiles of various DAAs in relation to OATP2B1 function in order to avoid unexpected DDIs. Therefore, using a cell-based transport assay, this study aimed at clarifying such DAA inhibition characteristics towards OATP2B1 function. The results of co-incubation inhibition assays showed that SMV and ASV strongly inhibited estrone sulfate (5 nM) uptake by OATP2B1, with half maximal inhibitory concentrations of 0.49 ± 0.12 μM and 0.16 ± 0.06 μM, respectively. Furthermore, it was found that SMV and ASV imposed long-lasting pre-incubation inhibitory effects on OATP2B1 function that enhanced their co-incubation inhibition potencies. On the other hand, no (or much less significant) inhibitory effects were observed for SOF or DCV. To summarise, these results show that SMV and ASV are co-incubation, as well as long-lasting pre-incubation, inhibitors of OATP2B1 function and therefore these inhibitions may lead to clinically relevant DDIs when used with OATP2B1 substrates. [ABSTRACT FROM AUTHOR]

To create a nanoscale dual switch, two responsive DNA motifs, azobenzene-modified DNAs and G-telomeric repeat sequences, were introduced together into the nanoframe system. The dualswitching behaviors controlled by photoirradiation and K+ were successfully visualized in real time by high-speed atomic force microscopy. [ABSTRACT FROM AUTHOR]

The digestive function of the stomach depends on acidification of the gastric lumen. Acid secretion into the lumen is triggered by activation of a cAMP-dependent protein kinase (PKA) cascade, which ultimately results in the insertion of gastric H,KATPases into the apical plasma membranes of parietal cells. A coupling protein is ezrin whose phosphorylation at Ser-66 by PKA is required for parietal cell activation. However, little is known regarding the molecular mechanism(s) by which ezrin operates in gastric acid secretion. Here we show that phosphorylation of Ser-66 induces a conformational change of ezrin that enables its association with syntaxin 3 (Stx3) and provides a spatial cue for H,K-ATPase trafficking. This conformation-dependent association is specific for Stx3, and the binding interface is mapped to the N-terminal region. Biochemical analyses show that inhibition of ezrin phosphorylation at Ser-66 prevents ezrin-Stx3 association and insertion of H,K-ATPase into the apical plasma membrane of parietal cells. Using atomic force microscopic analyses, our study revealed that phosphorylation of Ser-66 induces unfolding of ezrin molecule to allow Stx3 binding to its N terminus. Given the essential role of Stx3 in polarized secretion, our study presents the first evidence in which phosphorylation-induced conformational rearrangement of the ezrin molecule provides a spatial cue for polarized membrane trafficking in epithelial cells. [ABSTRACT FROM AUTHOR]

Ionotropic glutamate receptors are widely distributed in the central nervous system and play a major role in excitatory synaptic transmission. All three ionotropic glutamate subfamilies (i.e. AMPA-type, kainate-type, and NMDA-type) assemble as tetramers of four homologous subunits. There is good evidence that both heteromeric AMPA and kainate receptors have a 2:2 subunit stoichiometry and an alternating subunit arrangement. Recent studies based on presumed structural homology have indicated that NMDA receptors adopt the same arrangement. Here, we use atomic force microscopy imaging of receptor-antibody complexes to show that whereas the GluA1/GluA2 AMPAreceptor assembles with an alternating (i.e. 1/2/1/2) subunit arrangement, the GluN1/GluN2A NMDA receptor adopts an adjacent (i.e. 1/1/2/2) arrangement. We conclude that the two types of ionotropic glutamate receptor are built in different ways from their constituent subunits. This surprising finding necessitates a reassessment of the assembly of these important receptors. [ABSTRACT FROM AUTHOR]