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Searchable encryption technology can realize keyword search without decrypting the data,and thus well protects user'sprivate information.Aiming at the problem that most current searchable encryption schemes cannot support user-defined search strategies,this paper proposes an attribute-based searchable encryption scheme which is secure,efficient and can support arbitrary search expressions.Firstly,the scheme,based on LSSS access structure,allows keyword search policy to be represented by conjunction,disjunction or any monotone Boolean expression,user generates trapdoor for LSSS search policy by utilizing the private key,and cloud server can search ciphertexts that satisfy specific keywords search policy through trapdoor.Secondly,it can realize fine-grained access control of encrypted data in cloud through combining with attribute-based encryption scheme.In addition,attackers cannot infer the sensitive information of keyword values from ciphertext and trapdoor by splitting keywords into keyword names and values through "linear splitting" technology.Finally,the computing burden of users is reduced due to part of decryption work is transfered to cloud server.The security of the proposed scheme is proved based on BDHE,(q-2) assumption.Theoretical analysis and experimental results also show that the scheme is effective.

The aim of this study is to construct a lentiviral vector encoding human growth hormone, and to achieve the long, efficient and stable expression in murine skeletal myoblasts. Primary skeletal myoblasts were isolated from Sprague-Dawley rats and cultured by enzymatic digestion. We tested them by Desmin immunohistochemistry stains and found their viability was up to 94% by Trypan blue. Human growth hormone (hGH) cDNA was subcloned into expression vector pLenti6/V5-D-TOPO to construct recombinant pLenti6/V5-hGH. The pLenti6/V5-hGH and the contructed pLenti6/V5-EGFP were transfected into murine skeletal myoblasts by the Lipofectamin 2000. Through counting by the Confocal Laser Scanning Microscope, we identified the transfection efficency. We added the blasticidin to the 6-well plate with lids and obtained stable myoblasts expressing hGH. The concentration of human growth hormone (hGH) in cell culture medium was detected by Radioimmunoassay (RIA). Polymerase Chain Reaction (PCR) and DNA sequence showed hGH cDNA had been correctly inserted into pLenti6/V5-D-TOPO vector. Bright green fluorescence of the transfected cells could be observed under the Confocal Laser Scanning Microscope after 24 h transfection with pLenti6/V5-EGFP plasmids, and the transfection rate reached 40%. The difference was distinct (P < 0.01) between the pLenti6/V5- hGH groups and control groups in the secretive level of human growth hormone. After 8 weeks, the expression of human growth hormone was still stable. Then, we validated the biological characterization of the rhGH by the enzyme-link immunosorbent assay (ELISA) of the Insulin-like growth factor I (IGF-1). These results demonstrate we have successfully constructed the recombinant pLenti6/V5-hGH plasmids and accomplished rhGH long, efficient and stable expression ectopic in skeletal muscle myoblasts.