Effects of Co content on the Cu diffusion barrier property of electroless NiCoP film

The characteristics of electroless NiCoP films were investigated as a function of Co content. Sheet resistance of a multi-stacked film of SiO₂/Ta/Cu/NiP dramatically increased after annealing at 500 °C, but as more Co was co-plated in NiCoP film, the change in sheet resistance of the stacked film of SiO₂/Ta/Cu/NiCoP at 500 °C became smaller. A CoP/Cu film showed no change in resistance value after annealing, which indicates the CoP film is the most effective Cu diffusion barrier. X-ray diffraction analysis showed that an as-plated NiP film of amorphous structure is easily crystallized by thermal annealing over 300 °C, while CoP showed an insignificant change in crystal structure by thermal annealing up to 500 °C. This result reveals that the CoP film is capable of preventing the diffusion of Cu at 500 °C due to the thermal stability of CoP film.     

Monitoring nonlinear profiles using a wavelet-based distribution-free CUSUM chart

WDFTC is a wavelet-based distribution-free CUSUM chart for detecting shifts in the mean of a profile with noisy components. Exploiting a discrete wavelet transform (DWT) of the mean in-control profile, WDFTC selects a reduced-dimension vector of the associated DWT components from which the mean in-control profile can be approximated with minimal weighted relative reconstruction error. Based on randomly sampled Phase I (in-control) profiles, the covariance matrix of the corresponding reduced-dimension DWT vectors is estimated using a matrix-regularisation method; then the DWT vectors are aggregated (batched) so that the non-overlapping batch means of the reduced-dimension DWT vectors have manageable covariances. To monitor shifts in the mean profile during Phase II operation, WDFTC computes a Hotelling's T ²-type statistic from successive non-overlapping batch means and applies a CUSUM procedure to those statistics, where the associated control limits are evaluated analytically from the Phase I data. Experimentation with several normal and non-normal test processes revealed that WDFTC was competitive with existing profile-monitoring schemes.     

Citrus-derived auraptene stimulates angiogenesis by activating the Erk- and PI3K/Akt/eNOS-dependent signaling pathways in human umbilical vein endothelial cells

Auraptene is a citrus-derived natural monoterpene that has been shown to exert anti-cancer, anti-bacterial, anti-inflammatory, and antioxidant roles. Since little is known about other biological functions of auraptene, we examined the efficacy of auraptene for stimulating angiogenesis in human umbilical vein endothelial cells (HUVECs). Treatment with low concentrations of auraptene stimulated endothelial cell proliferation, migration, and tube formation. Furthermore, auraptene activated Erk, Akt, and endothelial nitric oxide synthase (eNOS), and increased NO production. Auraptene also partially induced the phosphorylation of VEGFR2. Furthermore, auraptene-induced activation of Erk, Akt, and eNOS were significantly inhibited by the inhibitors PD98059, LY294002, and l-NIO dihydrochloride. These results suggest that auraptene stimulates angiogenesis by regulating the VEGFR2, Erk, and PI3K/Akt-eNOS signaling pathways.     

Mobile Robot Navigation Using Wireless Sensor Networks Without Localization Procedure

In this paper, algorithms for navigating a mobile robot through wireless sensor networks are presented. The mobile robot can navigate without the need for a map, compass, or GPS module while interacting with neighboring sensor nodes. Two navigation algorithms are proposed in this paper: the first uses the distance between the mobile robot and each sensor node and the second uses the metric calculated from one-hop neighbors’ hop-counts. Periodically measuring the distance or metric, the mobile robot can move toward a point where these values become smaller and finally come to reach the destination. These algorithms do not attempt to localize the mobile robot for navigation, therefore our approach permits cost-effective robot navigation while overcoming the limitations of traditional navigation algorithms. Through a number of experiments and simulations, the performance of the two proposed algorithms is evaluated.     

Large Scale Indoor Localization System Based on Wireless Sensor Networks for Ubiquitous Computing

The task of formulating an efficient system for determining the location of an object, results in the creation of a wide number of applications and services. For this reason, most wireless sensor network applications assume the availability of sensor location information. In this paper, an indoor localization scheme, which is based on synchronized sensor nodes, is proposed. It is efficient in terms of power consumption and location update rate. Furthermore, it resolves the scalability problem usually found in most conventional indoor localization systems in large scale indoor environments. The performance of the proposed scheme is evaluated through experimental implementation and is compared with the Cricket system. The results demonstrate that the proposed scheme is a promising and feasible localization system for a large scale indoor environment.     

Antioxidant activities of aqueous extracts from three cultivars of guava leaf

In order to obtain basic data required for utilization of guava leaf as a functional substance, the antioxidant activities of aqueous extracts from 3 cultivars of guava leaf (‘Apple color’, ‘Ruby’, and ‘Safeda’) were examined. The total phenolic contents of the aqueous extracts ranged from 257.38 to 293.25 mg/g gallic acid equivalents. DPPH, ABTS, reducing power, ferric reducing antioxidant power (FRAP), ferric thiocyanate (FTC), and malondialdehyde (MDA) assays indicated that the aqueous extract of the ‘Ruby’ cultivar was the most potent radicalscavenger and reducing agent compared to the other 2 cultivars. Therefore, this study verified that aqueous extract from the ‘Ruby’ cultivar possessed strong antioxidant activity that correlated to its high level of phenolics, particularly gallic acid. In conclusion, the aqueous extract of the ‘Ruby’ cultivar of guava leaf may be utilized as an effective source of functional food materials, including natural antioxidants.     

Scalable and efficient approach for secure group communication using proxy cryptography

Multicast is a scalable solution for group communications. In order to offer security for multicast applications, a group key has to be changed whenever a member joins or leaves the group. This incurs 1-affects-n problem, which is a constraint on scalability. Decentralized approaches solve the scalability problem by dividing a group into several subgroups that use independent group keys. These approaches, however, introduce new challenges: problem of trusting third party and inefficiency of data delivery. Proxy encryption is a good approach to solve the problem of trusting third party. In this paper, we propose a novel secure multicast scheme using the proxy cryptography. The proposed scheme provides not only scalability but also data transmission efficiency by dynamic subgrouping of group members while intermediate data-relaying third parties are not required to be trusted.     

Highly Crystalline Soluble Acene Crystal Arrays for Organic Transistors: Mechanism of Crystal Growth During Dip‐Coating

The preparation of uniform large‐area highly crystalline organic semiconductor thin films that show outstanding carrier mobilities remains a challenge in the field of organic electronics, including organic field‐effect transistors. Quantitative control over the drying speed during dip‐coating permits optimization of the organic semiconductor film formation, although the kinetics of crystallization at the air–solution–substrate contact line are still not well understood. Here, we report the facile one‐step growth of self‐aligning, highly crystalline soluble acene crystal arrays that exhibit excellent field‐effect mobilities (up to 1.5 cm V^?1 s^?1) via an optimized dip‐coating process. We discover that optimized acene crystals grew at a particular substrate lifting‐rate in the presence of low boiling point solvents, such as dichloromethane (b.p. of 40.0 °C) or chloroform (b.p. of 60.4 °C). Variable‐temperature dip‐coating experiments using various solvents and lift rates are performed to elucidate the crystallization behavior. This bottom‐up study of soluble acene crystal growth during dip‐coating provides conditions under which one may obtain uniform organic semiconductor crystal arrays with high crystallinity and mobilities over large substrate areas, regardless of the substrate geometry (wafer substrates or cylinder‐shaped substrates).     

Antioxidant activity and hepatoprotective effect of Schizandra chinensis Baill. Extracts containing active components in alcohol-induced HepG2 cells

The antioxidant activities and hepatoprotective effects of Schizandra chinensis Baill. extracts (SCE) were evaluated. The contents of the active components schisandrin, schisandrin C, gomisin A, and gomisin N in SCE were 8.802±1.390, 1.011±0.203, 0.954±0.191, and 3.351±0.829 mg/g, respectively. The antioxidant activity of SCE was measured based on the DPPH free radical scavenging activity and the superoxide dismutase (SOD)-like activity. The IC₅₀ values for the DPPH radical scavenging activity and SOD-like activity were 18.1 and 44.2mg/mL, respectively. The protective effect of SCE against alcohol-induced oxidative injury in HepG2 cells was investigated. Cells pretreated with SCE (100–400 μg/mL) showed an increased resistance to oxidative stress in a dose-dependent manner. Expressions of Bcl-2 and pro-caspase-3 proteins were induced by SCE in HepG2 cells. SCE can be useful for management of antioxidant and hepatoprotective effects.     

Steam reforming of glycerol into hydrogen over nano-size Ni-based hydrotalcite-like catalysts

Steam reforming (SR) of glycerol for the production of hydrogen was investigated over the nano-sized Ni-based catalysts. The Ni-based catalysts were prepared by solid phase crystallization and impregnation methods, and characterized by N2 physisorption, CO chemisorption, XRD, SEM, and TEM techniques. The Ni/gamma-Al2O3 catalyst showed higher conversion and H2 selectivity. However, it was slowly deactivated due to the carbon formation on the surface of catalyst and the sintering. It was found that the Ni based hydrotalcite-like catalyst (spc-Ni/MgAl) showed higher catalytic activity to prevent carbon formation than Ni/gamma-Al2O3 catalyst in the SR of glycerol.