To validate the ability of full configuration interaction quantum Monte Carlo （FCIQMC） for studying the 2D Hubbard model near half-filling regime, the ground state energies of a 4×44×4 square lattice syste...To validate the ability of full configuration interaction quantum Monte Carlo （FCIQMC） for studying the 2D Hubbard model near half-filling regime, the ground state energies of a 4×44×4 square lattice system with various interaction strengths are calculated. It is found that the calculated results are in good agreement with those obtained by exact diagonalization （i.e., the exact values for a given basis set） when the population of psi particles （psips） is higher than the critical population required to correctly sample the ground state wave function. In addition, the variations of the average computational time per 20 Monte Carlo cycles with the coupling strength and the number of processors are also analyzed. The calculated results show that the computational efficiency of an FCIQMC calculation is mainly affected by the total population of psips and the communication between processors. These results can provide useful references for understanding the FCIQMC algorithm, studying the ground state properties of the 2D Hubbard model for the larger system size by the FCIQMC method and using a computational budget as effectively as possible.展开更多
Transcription factor SPI is a protcin present in mammalian cells that binds to GC box promoter clements of Gene and selectively activates mRNA synthesis. The gene contains functional recognition sites. It contains thr...Transcription factor SPI is a protcin present in mammalian cells that binds to GC box promoter clements of Gene and selectively activates mRNA synthesis. The gene contains functional recognition sites. It contains three continuous zinc finger motifs, which are believed being mctalloprotein structures that interact with DNA. We synthesized the second zine finger fragment of SP1 (SP1-ZF2) and its mutant (SP1-ZF2 / HT. E20→H. R23→T), we also synthesized the Cys-Cys loop (ZF6) and the His-His loop (ZF5) of SPI and linked the twoloops together using a β-turn structure to obtain a finger mimic analogue (ZF-15) by stepwise solid-phase technique. Atomic absorption studies show that SP 1-ZF2 and SP1-ZF2 / HT bind zinc cquimolarly, but ZF-15 docs not bind Zn anyway. The CD experiments demonstrate a significant change in secondary structure in the prescnce or absence of Zn to SP1-ZF2 and SP1-ZF2/ HT, but there is no change about ZF-15. Gcl-retardation clectrophoresis assays indicate that SP1-ZF2 binds to DNA sequence specifically in the presence of Zn, but SP1-ZF2 / HT docs not bind as SP 1-ZF2 did. We observed that a single zine finger like SP1-ZF2 is able to bind DNA sequence specifically.展开更多
基金Supported by the Natural Science Foundation for Colleges and Universities of Jiangsu Province under Grant No 16KJB140008the National Natural Science Foundation of China under Grant Nos 11447204 and 11647164+1 种基金the Natural Science Foundation of Jiangsu Province under Grant No BK20151079the Scientific Research Foundation of Nanjing Xiaozhuang University under Grant No 2015NXY34
文摘To validate the ability of full configuration interaction quantum Monte Carlo （FCIQMC） for studying the 2D Hubbard model near half-filling regime, the ground state energies of a 4×44×4 square lattice system with various interaction strengths are calculated. It is found that the calculated results are in good agreement with those obtained by exact diagonalization （i.e., the exact values for a given basis set） when the population of psi particles （psips） is higher than the critical population required to correctly sample the ground state wave function. In addition, the variations of the average computational time per 20 Monte Carlo cycles with the coupling strength and the number of processors are also analyzed. The calculated results show that the computational efficiency of an FCIQMC calculation is mainly affected by the total population of psips and the communication between processors. These results can provide useful references for understanding the FCIQMC algorithm, studying the ground state properties of the 2D Hubbard model for the larger system size by the FCIQMC method and using a computational budget as effectively as possible.
文摘Transcription factor SPI is a protcin present in mammalian cells that binds to GC box promoter clements of Gene and selectively activates mRNA synthesis. The gene contains functional recognition sites. It contains three continuous zinc finger motifs, which are believed being mctalloprotein structures that interact with DNA. We synthesized the second zine finger fragment of SP1 (SP1-ZF2) and its mutant (SP1-ZF2 / HT. E20→H. R23→T), we also synthesized the Cys-Cys loop (ZF6) and the His-His loop (ZF5) of SPI and linked the twoloops together using a β-turn structure to obtain a finger mimic analogue (ZF-15) by stepwise solid-phase technique. Atomic absorption studies show that SP 1-ZF2 and SP1-ZF2 / HT bind zinc cquimolarly, but ZF-15 docs not bind Zn anyway. The CD experiments demonstrate a significant change in secondary structure in the prescnce or absence of Zn to SP1-ZF2 and SP1-ZF2/ HT, but there is no change about ZF-15. Gcl-retardation clectrophoresis assays indicate that SP1-ZF2 binds to DNA sequence specifically in the presence of Zn, but SP1-ZF2 / HT docs not bind as SP 1-ZF2 did. We observed that a single zine finger like SP1-ZF2 is able to bind DNA sequence specifically.
