High secure sequence design in frequency hopping communications

Frequency-hopping (FH) technique is widely used in high-secure communications by exploiting its capabilities of mitigating interference and confidentiality. However, electronic attacks in wireless systems become more and more rigorous, which poses huge challenges to the use of the number theory based and chaos theory assisted sequences. The structure of the FH sequence directly affects the performance of FH communication systems. In this paper, the novel FH sequence generation scheme is proposed with the aid of the so-called Government Standard (GOST) algorithm, which achieves a promising balance between efficiency and security. Moreover, the security performance of the proposed algorithm is analyzed, which reveals that it is more resistant to impossible differential attacks than the widely-used Data Encryption Standard (DES) algorithm. The numerical results show that the FH sequences generated by the GOST algorithm significantly outperform the ones generated by the DES algorithm and chaotic theory in terms of the randomness and complexity

Identification of novel piperazinylquinoxaline derivatives as potent phosphoinositide 3-kinase (PI3K) inhibitors.

Development of small-molecule inhibitors targeting phosphoinositide 3-kinase (PI3K) has been an appealing strategy for the treatment of various types of cancers.Our approach was to perform structural modification and optimization based on previously identified morpholinoquinoxaline derivative WR1 and piperidinylquinoxaline derivative WR23 with a total of forty-five novel piperazinylquinoxaline derivatives synthesized. Most target compounds showed low micromolar to nanomolar antiproliferative potency against five human cancer cell lines using MTT method. Selected compounds showed potent PI3Kα inhibitory activity in a competitive fluorescent polarization assay, such as compound 22 (IC(50) 40 nM) and 41 (IC(50): 24 nM), which induced apoptosis in PC3 cells. Molecular docking analysis was performed to explore possible binding modes between target compounds and PI3K.The identified novel piperazinylquinoxaline derivatives that showed potent PI3Kα inhibitory activity and cellular antiproliferative potency may be promising agents for potential applications in cancer treatment

Study on the Galvanic Interaction of Gold and Main Associated Minerals Based on Density Functional Theory

The galvanic interaction of gold and associated sulfide minerals in thiocyanate systems has a significant impact on gold leaching. The density functional theory was used to further reveal the galvanic interaction between gold and associated minerals. The electron transfer between gold and its associated minerals at different galvanic interaction distances was simulated. The results show that with the increase of the contact distance between pyrite and gold, the charge of pyrite increases, indicating that it is losing electrons gradually; the charge of arsenopyrite and chalcocite decreases with the rise of the contact distance between gold and pyrite, suggesting that they are gaining electrons. In addition, gold has the greatest influence on the gain and loss of electrons in pyrite and arsenopyrite and has the least influence on chalcocite. Through the calculation of the density of states, it is found that different distances of galvanic interaction have a great influence on the density of states of surface atoms under the action of pyrite and arsenopyrite with gold but have little effect on the density of states of surface atoms under the action of chalcocite with gold