Incentive‐rewarding mechanism to stimulate activities in social networking services

We have developed an incentive‐rewarding mechanism that stimulates activities in social networking services (SNSs), including content uploading and link establishment. We particularly focus on changing the reward assignment ratio based on the different risks users perceive when uploading content with different privacy settings: public‐open and friend‐limited. Learning‐based simulation allowed us to observe that SNS activity, which we measured as the amount of browsed content within a certain period, can be controlled by a rewarding assignment ratio. We then analyzed how the amount of uploaded content and the increase of established links affect SNS activity. Results suggested that the optimal reward assignment ratio to maximize SNS activity changes depending on the total amount of available reward resources. Copyright © 2011 John Wiley & Sons, Ltd.     

Enzymatic digestion of corncobs pretreated with low strength of sulfuric acid for bioethanol production

In this study, the effect and the optimum pretreatment condition of corncobs using low strength of H₂SO₄ were investigated, in which H₂SO₄ was used to improve the enzymatic digestibility of corncobs for saccharification without degradation of sugars released. The optimum pretreatment condition was found to be the addition of 0.5% (vol./vol.) H₂SO₄ and autoclaving at 122 °C for 20 min. Under this condition, the structural integrity of corncob was altered to make cellulose microfibrils more accessible for cellulase enzymes, and the enzymatic digestion of corncobs could be significantly enhanced. A high yield of sugar, 80% (wt./wt.), could be obtained at a low enzyme dosage of 0.024 g enzymes/g cobs, when pretreated. As a result, the ethanol production was obviously improved by the pretreatment, i.e., the ethanol yield of 77% (wt./wt.) was obtained within 36 h in the SSF fermentation using Saccharomyces cerevisiae NBRC2114.     

Improvement in D-E Hysteresis Curve Squareness of PZT Thin Films—Effect of Oxygen Partial Pressure in High-Pressure Post-Annealing

A high-pressure annealing was applied to a post-annealing process for sol-gel derived PZT thin films. The squareness of D-E hysteresis curves changes depending on both total pressure and oxygen concentration. Moreover, the change follows the product of the total pressure and the oxygen concentration, which correspond to oxygen partial pressure P_O2. Where the P_O2 is higher than 0.03 MPa, few of the squareness of the hysteresis curve are excellent. The squareness of the hysteresis curves dramatically improve as the P_O2 decreases. Where the P_O2 is lower than 0.01 MPa, the squareness deteriorates slightly. These changes in the D-E hysteresis curves are thought to be explained by the generation of lead and oxygen vacancies as a function of the P_O2.     

Inclusion complexation of (11-ferrocenylundecyl)trimethylammonium bromide by β-cyclodextrin and its effects on electrochemical behavior of the surfactant

This report describes the influence of β-cyclodextrin complexation on thermodynamic and kinetic parameters of the electrode reaction of (11-ferrocenylundecyl)trimethylammonium bromide in aqueous media. The host attracted the reduced form having a less positive charge more strongly than the corresponding oxidized one. Thus, a hydrophobic interaction between the non-polar host cavity and the ferrocene moiety plays an important role in the inclusion complexation. Fast-scan voltammetric behavior of the amphiphilic ion suggested that inclusion-ejection processes practically attain equilibrium in the scan-rate range below 10 V s⁻¹, because of their fast rates. The relation between the peak current and peak potential leads to the conclusion that the enveloped guest exchanges no electrons directly with an electrode. The mean diffusion coefficient of the surfactant can be written as a linear combination of the contributions from a free monomolecular, a micelle-forming, and a host-bound surfactant. Since the binding affinity of the ferrocene moiety for the host cavity is much stronger than the aggregation force between the amphiphilic molecules in aqueous media, the host disrupts the micelles by incorporating the surfactant molecule into its cavity.     

Interfacial charge-transfer resistance at ionizable thiol monolayer-modified gold electrodes as studied by impedance spectroscopy

This paper examines the influences of ionizable thiol monolayers on the interfacial charge-transfer rates for redox-active ions by electrochemical impedance spectroscopy. Whereas short-chain thiols such as 4-aminothiophenol hardly affected the charge-transfer resistance for Ru(NH₃)₆³⁺ having a high standard heterogeneous rate constant, the 11-mercaptoundecanoic acid monolayer raised this resistance to 3×10⁴ times that observed at a bare electrode in acidic solutions. As the terminal carboxyl group ionized, the charge-transfer resistance decreased by a factor of 300 because of a double-layer effect. When 3-mercaptopropionic acid was mixed with 1-hexadecanethiol, the charge-transfer resistance varied over four orders of magnitude with the composition of the two-component monolayer. The apparent rate constant for indigotetrasulfonate at 4-aminothiophenol-modified electrodes decreased by a factor of 25-30 as the solution pH varied from 4 to 2. This decrease was opposite to the change expected from protonation of the terminal amino group. It can be ascribed to a strong binding interaction between the redox anion and the positively charged monolayer.     

Applicability of AE monitoring technique to evaluate structural integrity of fast breeder reactor piping component

The availability of acoustic emission technique for detecting and monitoring defects of piping components in fast breeder reactors has been studied in the FAET Committee of the Japan Welding Engineering Society sponsored by,the Power Reactor & Nuclear Fuel Development Corporation. The researches which extended over four years have covered a wide range of experiments and evaluations in order to ensure the usefulness of the acoustic emission technique as a monitoring tool of plant operation.     

Frictional Anisotropy of Oblique Nanocolumn Arrays Grown by Glancing Angle Deposition

Frictional anisotropy of oblique Ti nanocolumns grown by glancing angle deposition (GLAD) was investigated by ramp-scratch experiments in forward (in the direction of the column tilt) and reverse (against the column tilt) directions using rectangular and conical loading tips. Strong anisotropy in friction was generally observed, wherein the resistance or friction coefficient in reverse scratching was higher than that in forward scratching, and the reverse resistance was sensitive to the tip shape. In forward scratching, the nanocolumns bend with the column tilt direction, designated as the W-mode deformation. On the other hand, in reverse scratching, the nanocolumns deflect against the column tilt in high normal force, designated as the A-mode deformation. The deformation mode changes from the W-mode to the A-mode as the normal force increases in reverse scratching. The mechanism of the frictional anisotropy was discussed on the basis of a simple deformation model of column by finite element method. The anisotropy can be explained by the difference in the deformation mode. That is, compressive deformation in the longitudinal direction and large deflection against the column tilt induce higher friction resistance in reverse scratching than in forward scratching brought about by compliant bending deformation with the column tilt.     

Block Copolymer Permeable Membrane with Visualized High‐Density Straight Channels of Poly(ethylene oxide)

A simple fabrication, scalable to centimeter scale, of a permeable membrane made of block copolymer containing molecular transport channels is demonstrated by coating photo‐crosslinkable liquid‐crystalline block copolymer, consisting of poly(ethylene oxide) (PEO) and poly(methacrylate) (PMA) bearing stilbene (Stb) mesogens in the side chains (PEO₁₁₄‐b‐PMA(Stb)₅₂), onto a sacrificial cellulose acetate film substrate. After thermal annealing, perpendicularly aligned and hexagonally arranged PEO cylindrical domains with a surface density of 10¹¹ cm^?2 were formed and then fixed efficiently by photo‐crosslinking the stilbene moieties in the PMA(Stb) domains by [2 + 2] dimerization. The fully penetrating straight PEO cylindrical domains across the 480‐nm‐thick membrane were well‐defined and visualized as molecule‐transport channels. After exfoliated by removal of the cellulose acetate layer, the membrane could be transferred onto another substrate by either scooping or a horizontal lifting method. Throughout the processes, the fully penetrating PEO channels across the membrane are preserved to open at both ends. A simple permeation experiment demonstrates that rhodamine dyes permeate efficiently through the PEO cylindrical channels of the annealed membrane but not across a non‐annealed one.     

Temperature dependence of cyclic creep behavior of a Cu–SiO2 bicrystal with a [0 1 1] 20° twist boundary

Temperature dependence of cyclic creep behavior has been studied using a Cu bicrystal containing dispersed SiO₂ particles and a [0 1 1] 20° twist boundary. Failure occurred at shorter times with increasing temperature and stress amplitude. The fracture-mode of the bicrystals changed sharply from transgranular to intergranular at a certain critical stress amplitude. The brittle intergranular fracture that occurred below the critical stress amplitude caused discontinuous life shortening. The observed fracture-mode change at the critical stress amplitude is discussed in relation to grain-boundary sliding and grain-boundary cracking.     

A comparative study of transcranial Doppler sonography and near-infrared spectroscopy for the assessment of cerebrovascular CO2 reactivity

Oleanolic acid (1) was identified as an anti-HIV principle from several plants, including Rosa woodsii (leaves), Prosopis glandulosa (leaves and twigs), Phoradendron juniperinum (whole plant), Syzygium claviflorum (leaves), Hyptis capitata (whole plant), and Ternstromia gymnanthera (aerial part). It inhibited HIV-1 replication in acutely infected H9 cells with an EC50 value of 1.7 microg/mL, and inhibited H9 cell growth with an IC50 value of 21.8 microg/mL [therapeutic index (T. I.) 12.8]. Pomolic acid, isolated from R. woodsii and H. capitata, was also identified as an anti-HIV agent (EC50 1.4 microg/mL, T. I. 16.6). Although ursolic acid did show anti-HIV activity (EC50 2.0 microg/mL), it was slightly toxic (IC50 6.5 microg/mL, T. I. 3.3). A new triterpene (11) was also isolated from the CHCl3-soluble fraction of R. woodsii, though it showed no anti-HIV activity. The structure of 11 was determined to be 1beta-hydroxy-2-oxopomolic acid by spectral examination. Based on these results, we examined the anti-HIV activity of oleanolic acid- or pomolic acid-related triterpenes isolated from several plants. In addition, we previously demonstrated that derivatives of betulinic acid, isolated from the leaves of S. claviflorum as an anti-HIV principle, exhibited extremely potent anti-HIV activity. Accordingly, we prepared derivatives of oleanolic acid and evaluated their anti-HIV activity. Among the oleanolic acid derivatives, 18 demonstrated most potent anti-HIV activity, with an EC50 value of 0. 0005 microg/mL and a T. I. value of 22 400.