Driving frequency dependency of gas species in the bubble formation for aqua-plasma generation

Effects of voltage driving frequency on the gas composition, electrical and optical emission properties of aqua-plasmas generated in electrolyte solution, are investigated and the experiment was carried out in the range of 10 Hz–50 kHz. In the range of 10–300 Hz, H₂ dominated bubbles are generated and it is attributed to electrolysis. With increasing frequency, the gas composition inside the bubble changes to the H₂O which can be determined from the observation of atomic H to OH(A-X) transition from the optical measurements of aqua-plasma. In higher frequency than 2 kHz, the boiling on the electrode dominates to the formation of the bubble. Consequently, the radicals and plasma properties are varied with the driving frequency.     

Transfer of functional memory devices to any substrate

Electronic devices on unconventional substrates are attractive beyond the conventional solid‐state rigid electronic system or even flexible electronics. Here, by use of the transfer printing technique, we report the memory devices onto a range of unconventional substrates, including paper, an insect (cicada), glass, polyethersulphone, polyimide, double‐sided tape, Al foil, fabric, a mask, a leather wallet, a name card, a banknote, a latex glove, and a squeezed plastic bottle. The device can be possibly realized on any substrate. The memory structure used in this work is non‐volatile resistive random access memory (RRAM). Constraints imposed by process compatibility between the substrates and device materials are completely eliminated by the use of the transfer printing techniques. It is confirmed that the electrical characteristics of the RRAM devices do not degrade during the transfer process. Stable resistive switching properties, reliable endurance levels, and good retention characteristics are demonstrated. The mechanical stability is also analysed and an encapsulation protection layer on top of the memory devices is suggested for long‐term reliability. The possibility of the realization of integrated electronic systems onto various substrates will enable the versatile use of these electronics anywhere and anytime in many different environments.

     

Oriented immobilization of antibodies by a self-assembled monolayer of 2-(biotinamido)ethanethiol for immunoarray preparation

Orientation of antibodies is very important in the preparation of immunoarrays to keep the activity of antibodies on solid surfaces. Thus, we synthesized a new bifunctional compound, 2-(biotinamido)ethanethiol, and investigated whether the thiol compound is useful to analyze antibody-antigen interactions on immunoarrays with a spectral SPR biosensor. The synthesized organic thiol was characterized by nuclear magnetic resonance spectroscopy and mass spectrometry. 2-(Biotinamido)ethanethiol formed a monolayer on a gold surface and properly immobilized antibodies via streptavidin and biotinylated protein G. Optimal molar ratio of 2-(biotinamido)ethanethiol and mercaptohexanol for antigen-antibody interactions was 1:2. Thus, 2-(biotinamido)ethanethiol is an useful bifunctional linker in the preparation of immunoarrays on gold surfaces.     

Decreased expression of DNA repair proteins Ku70 and Mre11 is associated with aging and may contribute to the cellular senescence

The gradual loss of telomeric DNA can contribute to replicative senescence and thus, having longer telomeric DNA is generally considered to provide a longer lifespan. Maintenance and stabilization of telomeric DNA is assisted by binding of multiple DNA-binding proteins, including those involved in double strand break (DSB) repair. We reasoned that declining DSB repair capacity and increased telomere shortening in aged individuals may be associated with decreased expression of DSB repair proteins capable of telomere binding. Our data presented here show that among the DSB repair proteins tested, only the expression of Ku70 and Mre11 showed statistically significant age-dependent changes in human lymphocytes. Furthermore, we found that expressions of Ku70 and Mre11 are statistically correlated, which indicate that the function of Ku70 and Mre11 may be related. All the other DSB repair proteins tested, Sir2, TRF1 and Ku80, did not show any significant differences upon aging. In line with these data, people who live in the regional community (longevity group), which was found to have statistically longer average life span than the rest area, shows higher level of Ku70 expression than those living in the neighboring control community. Taken together, our data show, for the first time, that Ku70 and Mre11 may represent new biomarkers for aging and further suggest that maintenance of higher expression of Ku70 and Mre11 may be responsible for keeping longer life span observed in the longevity group.     

Composite thermal conductivity in a large heterogeneous porous methane hydrate sample

By employing inverse modeling to analyze the laboratory data, we determined the composite thermal conductivity (k(theta), W/m/K) of a porous methane hydrate sample ranged between 0.25 and 0.58 W/m/K as a function of density. The calculated composite thermal diffusivities of porous hydrate sample ranged between 2.59 x 10(-7) m(2)/s and 3.71 x 10(-7) m(2)/s. The laboratory study involved a large heterogeneous sample (composed of hydrate, water, and methane gas). The measurements were conducted isobarically at 4.98 MPa over a temperature range of 277.3-279.1 K. Pressure and temperature were monitored at multiple locations in the sample. X-ray computed tomography (CT) was used to visualize and quantify the density changes that occurred during hydrate formation from granular ice. CT images showed that methane hydrate formed from granular ice was heterogeneous and provided an estimate of the sample density variation in the radial direction. This facilitated quantifying the density effect on composite thermal conductivity. This study showed that the sample heterogeneity should be considered in thermal conductivity measurements of hydrate systems. Mixing models (i.e., arithmetic, harmonic, geometric mean, and square root models) were compared to the estimated composite thermal conductivity determined by inverse modeling. The results of the arithmetic mean model showed the best agreement with the estimated composite thermal conductivity.     

Phase of molecular ink in nanoscale direct deposition processes

We report the first observation of a phase transition in a nanoscale direct deposition process. This transition involves the melting of molecular ink layers in dip-pen nanolithography, and it is observed by measuring the temperature dependence of the growth rate of the deposited pattern. The results are interpreted using a diffusion equation approach in conjunction with a "double-molecular-layer" model of the adsorbed molecules on the atomic force microscope tip. The theory provides a qualitative explanation for the dependence of the pattern growth rate on solvent and adsorbed water as well as on temperature.     

The impact of information technology on organizational efficiency in public services: a DEA-based DT approach

This study attempts to examine the impact of information technology (IT) on organizational efficiency in public services. We propose a new approach to providing the directions of IT investments to improve organizational efficiency. The proposed approach is based on the integrated form of data envelopment analysis (DEA) and decision tree (DT), and composed of two steps. First, DEA is conducted to measure organizational efficiency with the selected inputs and outputs. Second, DT is built based on efficiency scores obtained from DEA and IT factors, as a target variable and predictor variables, respectively. In doing so, we can identify the relative impact of IT investments on organizational efficiency and set priorities to the IT investments to improve efficiency from a view point of each organization. A case study on the Korean local governments is presented to illustrate the usefulness of the proposed approach.     

Studies on the steam CO2 reforming of methane over ordered mesoporous nickel–magnesium–alumina catalysts

Research on Chemical Intermediates - Ordered mesoporous materials have received much attention because of their high surface area and ordered pore structure. The Mg-promoted ordered mesoporous...     

Organic glass-forming materials: 1,3,5-tris(naphthyl)benzene derivatives

The organic glass-forming materials 1,3-bis(1-naphthyl)-5-(2-naphthyl)benzene (2) and its partially deuterated analogue, 1,3-bis(1-naphthyl-d(7))-5-(2-naphthyl)benzene (2-d(14)), have been synthesized on a gram scale using Suzuki coupling reactions. Detailed spectroscopic studies afford complete NMR assignments (1H, 2H, 13C) for both compounds. Modest energy barriers for the interconversion of atropisomers (ca. 15 kcal/mol) result in a propensity for these materials to form supercooled liquids and glasses, rather than undergoing crystallization. The preparation of these materials enables detailed studies of physical properties of organic glasses and molecular diffusion in condensed phases.     

Moment analysis of focus-diverse point spread functions for modal wavefront sensing of uniformly illuminated circular-pupil systems

A new concept of using focus-diverse point spread functions (PSFs) for modal wavefront sensing (WFS) is explored. This concept is based on relatively straightforward image moment analysis of measured PSFs, which differentiates it from other focal-plane WFS techniques. The presented geometric analysis shows that the image moments are nonlinear functions of wave aberration coefficients but notes that focus diversity essentially decouples the coefficients of interest from others, resulting in a set of linear equations whose solution corresponds to modal coefficient estimates. The presented proof-of-concept simulations suggest the potential of the concept in WFS with strongly aberrated high signal-to-noise ratio objects in particular.