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Monovalent salts are generally believed to stabilize DNA duplex by weakening inter-strand electrostatic repulsion. Unexpectedly, our force-induced hairpin unzipping experiments and thermal melting experiments show that LiCl, NaCl, KCl, RbCl, and CsCl at concentrations beyond ~1 M destabilize DNA, RNA, and RNA-DNA duplexes. The two types of experiments yield different changes in free energy during melting, while the results that high concentration monovalent salts destabilize duplexes are common. The effects of these monovalent ions are similar but also have noticeable differences. From 1 M to 4 M, DNA duplex is destabilized by about 0.3 kBT/bp and the melting temperature decreases by about 10 oC. Our all-atom simulations reveal this effect is caused by overcharging, where excessive ion absorption inverts the effective DNA charge from negative to positive. Furthermore, our coarse-grained simulations obtain a phase diagram that indicates whether DNA overcharging occurs at a given cation valence and concentration. These findings challenge the traditional belief that DNA overcharging occurs only with multivalent ions and have significant implications for polyelectrolyte theory, DNA nanomaterials, DNA nanotechnology, and DNA biophysics. Experiments and simulations suggest monovalent salts destabilize DNA/RNA because of overcharging. These findings challenge views that overcharging requires multivalent ions, with implications for nanomaterials, nanotechnology, and biophysics. [ABSTRACT FROM AUTHOR]

Blockchain is one of the technical hotspots in recent years,and the research theories related to it are being enriched.However,it is still facing the key problem of small throughput and low processing efficiency before it can be implemented into the industry.In response to this problem,cross-chain technology has been widely focused as a blockchain technology that has the potential to both expand throughput processing capacity and improve processing efficiency.This paper presents a novel hash-time-lock-contract based cross-chain token swap mechanism (NCASP),which creatively introduces an account system for the Fabric blockchain and integrates smart contract technology to achieve secure and seamless asset exchange between the Ethernet and Fabric blockchain network.The NCASP protocol sets up different intermediate accounts for asset escrow and transfer in each HTLC transfer,and destroys them in time after the transaction is completed,making the original cross-chain transaction rate unchanged while ensuring the security of the transaction.Simulation of the protocol shows that the protocol is applicable to the federated chain represented by Fabric and the public chains represented by Bitcoin and Ethernet,can achieve efficient and secure cross-chain asset exchange without the intervention of third-party blockchains,and can save about 26.8% in transaction efficiency compared with the cross-chain scheme of BSN (blockchain service network).The improved protocol extends the usage scenarios of the traditional HTLC cross-chain asset schemes,enabling the exchange of assets between different users with a balance of atomicity,fairness and transparency.

In order to solve the security of electronic transactions on limited goods, some quantum blind double signature (QBDS) protocols were proposed. In existing QBDS protocols, all participants must have specific quantum computing capabilities. Realistically, high cost of quantum devices may hinder people from using the QBDS protocol. Therefore, we propose a semi-quantum arbitrator blind double signature (SQABDS) scheme. In this scheme, the sender (signer) and the receiver both are classical participants, which can relatively reduce the dependence on quantum hardware. The introduction of blind signers can protect the privacy of electronic transactions, the introduction of semi-trusted arbitrator can relax the strong assumption about the trustworthiness of the arbitrator, for the arbitrator cannot forge the signature. In addition, the SQABDS scheme can be used to sign classical messages directly without performing any quantum swapping tests or quantum gate operations. Finally, the analysis shows that our scheme is securer and its quantum cost is relatively lower. [ABSTRACT FROM AUTHOR]

With the growing need for high-quality steel, the requirement for efficient deep desulfurization technologies is growing, and lots of research have be conducted. The desulfurization in hot iron with Mg produced in situ by the aluminothermic reduction of decomposed dolomite was simulated. The magnesium generated at the molten matte-slag interface is dissolved in the molten iron and desulfurizing while spread downwards The process has been studied by experiment and computational fluid dynamics simulation. Some analysis and assumptions were made for the simulation conditions and the simulated data are in good agreement with the experimental results. The rate of desulfurization depended mainly on the reaction rate and is almost independent of the rate of diffusion of Al, S and Mg according to the results. Under the present experimental conditions, the desulfurization rate increased with the increase in temperature and the amount of reactants. However, the effect is not obvious when the temperature is higher than 1623K. The adjustment in diffusion coefficient has minimal influence on the desulfurization efficiency. The desulfurization reaction is mainly in the homogeneous phase, and the proportion of magnesium bubble desulfurization could be ignored when the temperature is between 1523 K–1723 K.