Proxy Re-encryption based Fair Trade Protocol for Digital Goods Transactions via Smart Contracts

With the massive amount of digital data generated everyday, transactions of digital goods become a trend. One of the essential requirements for such transactions is fairness, which is defined as that both of the seller and the buyer get what they want, or neither. Current fair trade protocols generally involve a trusted third-party (TTP), which achieves fairness by heavily relying on the TTP's behaviors and the two parties' trust in the TTP. With the emergence of Blockchain, its decentralization and transparency make it a very good candidate to replace the TTP. In this work, we attempt to design a secure and fair protocol for digital goods transactions through smart contracts on Blockchain. To ensure security of the digital goods, we propose an advanced passive proxy re-encryption (PRE) scheme, which enables smart contracts to transfer the decryption right to a buyer after receiving his/her payment. Furthermore, based on smart contracts and the proposed passive PRE scheme, a fair trade protocol for digital goods transactions is proposed, whose fairness is guaranteed by the arbitration protocol. The proposed protocol supports Ciphertext publicity and repeatable sale, while involving less number of interactions. Comprehensive experiment results validate the feasibility and effectiveness of the proposed protocol

Reliability of plasma-etched copper lines on a glass substrate

Copper (Cu) thin films can be etched into 0.3 micrometer Cu patterns, as shown in Figure 1. This process has been used in the fabrication of large-area thin film transistor (TFT) arrays for LCDs, interconnect lines in high density BiCMOS circuits, and source, drain and gate electrodes of a-Si:H TFTs (1,2). The reliability of the Cu line is usually investigated with the isothermal electromigration (EM) method (3). In almost all studies, the Cu line was prepared on the silicon substrate coated with a dielectric layer. There are few studies on Cu line lifetime on the glass substrate. Also, the EM failure investigation was focused on the line broken time, which could be influenced by the edge roughness, step coverage, current density, etc. (4). The physical and structure changes of the Cu line during the EM stress time are often neglected (5). In this paper, authors discuss the application of the plasma etched Cu line for the SSI-LED array. It allows the driving of the individual device for light emitting at specified conditions, which enables applications in displays, optical interconnects, etc. The transformation of the Cu line from a continuous pattern to the broken state will be reviewed. The temperature change with respect to the stress current density and the lifetime will be discussed. In summary, the room temperature plasma-based Cu etch process can be applied to a wide range of electronic and optoelectronic products. The understanding of the reliability of the Cu line is important for these applications. Please click Additional Files below to see the full abstract

Splitting theorem, Poincaré–Hopf theorem and jumping nonlinear problems

AbstractIn this paper, we establish a Gromoll–Meyer splitting theorem and a shifting theorem for J∈C2-0E,R and by using the finite-dimensional approximation, mollifiers and Morse theory we generalize the Poincaré–Hopf theorem to J∈C1E,R case. By combining the Poincaré–Hopf theorem and the splitting theorem, we study the existence of multiple solutions for jumping nonlinear elliptic equations

Spatio-temporal variations and influencing factors of polycyclic aromatic hydrocarbons in atmospheric bulk deposition along a plain-mountain transect in western China

Ten atmospheric bulk deposition (the sum of wet and dry deposition) samplers for polycyclic aromatic hydrocarbons (PAHs) were deployed at a plain-mountain transect (namely PMT transect, from Daying to Qingping) in Chengdu Plain, West China from June 2007 to June 2008 in four consecutive seasons (about every three months). The bulk deposition fluxes of ∑15-PAHs ranged from 169.19 μg m−2 yr−1 to 978.58 μg m−2 yr−1 with geometric mean of 354.22 μg m−2 yr−1. The most prevalent PAHs were 4-ring (39.65%) and 3-ring (35.56%) PAHs. The flux values were comparable to those in rural areas. Higher fluxes of total PAHs were observed in the middle of PMT transect (SL, YX and JY, which were more urbanized than other sites). The seasonal deposition fluxes in the sampling profile indicated seasonality of the contaminant source was an important factor in controlling deposition fluxes. PAHs bulk deposition was negatively correlated with meteorological parameters (temperature, wind speed, humidity, and precipitation). No significant correlations between soil concentrations and atmospheric deposition were found along this transect. PAHs in soil samples had combined sources of coal, wood and petroleum combustion, while a simple source of coal, wood and grass combustion for bulk deposition. There were significant positive correlation relationship (p < 0.05) between annual atmospheric bulk deposition and local PAHs emission, with biomass burning as the major contribution to the total emission of PAHs. This transect acts as an important PAHs source rather than being a sink according to the ratio of deposition/emission. Mountain cold trap effect existed in this transect where the altitude was higher than 1000 m. Long-range transport had an impact on the bulk deposition in summer. And this transect was a source to Tibetan only in summer. The forward trajectory analysis showed most air masses did not undergo long-range transport due to the blocking effect of surrounding mountains. Only a few air masses (<10%) arrived at the eastern and northern region of China or farther regions via long-range transport

MutL sliding clamps coordinate exonuclease-independent Escherichia coli mismatch repair

A shared paradigm of mismatch repair (MMR) across biology depicts extensive exonuclease-driven strand-specific excision that begins at a distant single-stranded DNA (ssDNA) break and proceeds back past the mismatched nucleotides. Historical reconstitution studies concluded that Escherichia coli (Ec) MMR employed EcMutS, EcMutL, EcMutH, EcUvrD, EcSSB and one of four ssDNA exonucleases to accomplish excision. Recent single-molecule images demonstrated that EcMutS and EcMutL formed cascading sliding clamps on a mismatched DNA that together assisted EcMutH in introducing ssDNA breaks at distant newly replicated GATC sites. Here we visualize the complete strand-specific excision process and find that long-lived EcMutL sliding clamps capture EcUvrD helicase near the ssDNA break, significantly increasing its unwinding processivity. EcSSB modulates the EcMutL-EcUvrD unwinding dynamics, which is rarely accompanied by extensive ssDNA exonuclease digestion. Together these observations are consistent with an exonuclease-independent MMR strand excision mechanism that relies on EcMutL-EcUvrD helicase-driven displacement of ssDNA segments between adjacent EcMutH-GATC incisions.11Ysciescopu

On a boundary value problem in the half-space

AbstractIn this paper, we study the existence of positive solutions and sign-changing solutions for the following boundary value problem in the half-space{Δu=0,inR+N+1,∂u∂n+λg(x)u=f(u),on∂R+N+1, where λ is a positive parameter and the nonlinear term f is superlinear at zero and asymptotically linear at infinity

Soliton Solutions for Quasilinear Schrödinger Equations

For a class of quasilinear SchrSdinger equations we establish the existence of ground states of soliton type solutions by a minimization argument

Observing Protein One-Dimensional Sliding: Methodology and Biological Significance

One-dimensional (1D) sliding of DNA-binding proteins has been observed by numerous kinetic studies. It appears that many of these sliding events play important roles in a wide range of biological processes. However, one challenge is to determine the physiological relevance of these motions in the context of the protein’s biological function. Here, we discuss methods of measuring protein 1D sliding by highlighting the single-molecule approaches that are capable of visualizing particle movement in real time. We also present recent findings that show how protein sliding contributes to function