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The research study which was aimed at characterizing the chromosomal origin of replication (oriC) region of Mycobacterium smegmatis (M smegtatis) was conducted. The methods used were the recombinant DNA techniques, analysis of oriC activity, construction of oriC plasmids, site-directed mutagenesis, oriC copy number determination and stability experiments. Results suggested that M smegtatis oriC replication could involve interactions of DnaA protein with DnaA boxes and the DnaA boxes and AT nucleotide rich cluster are important to oriC activity.

A 4-kb chromosomal DNA fragment from Mycobacterium smegmatis that has a dnaA gene was studied to analyze mycobacteria's method of starting replication. Analysis of the nucleotide sequence showed homologies with the rpmH gene, which encodes the ribosomal protein L34, the dnaA gene, which encodes the replication initiator protein DnaA, and the 5' end of the dnaN gene, which encodes the beta subunit of DNA polymerase III.

A three-terminal device based on electronic phase separated manganites is suggested to produce high performance resistive switching. Our Monte Carlo simulations reveal that the conductive filaments can be formed/annihilated by reshaping the ferromagnetic metal phase domains with two cross-oriented switching voltages. Besides, by controlling the high resistance state (HRS) to a stable state that just after the filament is ruptured, the resistive switching remains stable and reversible, while the switching voltage and the switching time can be greatly reduced. [ABSTRACT FROM AUTHOR]

The ferroelectric polarization and phase diagram in Tm-doped GdMnO3 are studied by means of Monte Carlo simulation based on the Mochizuki–Furukawa model. Our work well reproduces the low temperature polarization at various substitution levels observed experimentally. It is demonstrated that the Tm-doping can control the multiferroic behaviors through modulating the spin structures, resulting in the flop of the electric polarization. In addition, the polarization in the ab-plane cycloidal spin phase arises from comparable contributions of the symmetric exchange striction and antisymmetric exchange striction, leading to much bigger polarization than that in the bc-plane cycloidal spin phase where only the contribution of the latter striction is available. The phase diagram obtained in our simulation is helpful for clarifying the multiferroic properties in doped manganite systems and other related multiferroics. [ABSTRACT FROM AUTHOR]

The structural and magnetic properties of the Cu-doped ZnO (ZnO:Cu) under c-axis pressure were studied using first-principle calculations. It was found that the ZnO:Cu undergoes a structural transition from Wurtzite to Graphite-like structure at a c-axis pressure of 7–8 GPa. This is accompanied by an apparent loss of ferromagnetic stability, indicating a magnetic transformation from a ferromagnetic state to a paramagnetic-like state. Further studies revealed that the magnetic instability is closely related to the variation in crystalline field originated from the structural transition, which is in association with the overlapping of spin–charge density between the Cu2+ and adjacent O2-. [ABSTRACT FROM AUTHOR]