High-Order Harmonic Generation and Molecular Orbital Tomography: Characteristics of Molecular Recollision Electronic Wave Packets

We investigate the orientation dependence of molecular high-order harmonic generation (HHG) both numerically and analytically. We show that the molecular recollision electronic wave packets (REWPs) in the HHG are closely related to the ionization potential as well as the particular orbital from which it ionized. As a result, the spectral amplitude of the molecular REWP can be significantly different from its reference atom (i.e., with the same ionization potential as the molecule under study) in some energy regions due to the interference between the atomic cores of the molecules. This finding is important for molecular orbital tomography using HHG[Nature \textbf{432}, 867(2004)].Comment: 4 pages, 4 figure

Bosonization of quantum sine-Gordon field with a boundary

Boundary operators and boundary ground states in sine-Gordon model with a fixed boundary condition are studied using bosonization and q-deformed oscillators.We also obtain the form-factors of this model.Comment: Latex 25page

In silico identification of a multi-functional regulatory protein involved in Holliday junction resolution in bacteria

BACKGROUND: Homologous recombination is a fundamental cellular process that is most widely used by cells to rearrange genes and accurately repair DNA double-strand breaks. It may result in the formation of a critical intermediate named Holliday junction, which is a four-way DNA junction and needs to be resolved to allow chromosome segregation. Different Holliday junction resolution systems and enzymes have been characterized from all three domains of life. In bacteria, the RuvABC complex is the most important resolution system. RESULTS: In this study, we conducted comparative genomics studies to identify a novel DNA-binding protein, YebC, which may serve as a key transcriptional regulator that mainly regulates the gene expression of RuvABC resolvasome in bacteria. On the other hand, the presence of YebC orthologs in some organisms lacking RuvC implied that it might participate in other biological processes. Further phylogenetic analysis of YebC protein sequences revealed two functionally different subtypes: YebC_I and YebC_II. Distribution of YebC_I is much wider than YebC_II. Only YebC_I proteins may play an important role in regulating RuvABC gene expression in bacteria. Investigation of YebC-like proteins in eukaryotes suggested that they may have originated from YebC_II proteins and evolved a new function as a specific translational activator in mitochondria. Finally, additional phylum-specific genes associated with Holliday junction resolution were predicted. CONCLUSIONS: Overall, our data provide new insights into the basic mechanism of Holliday junction resolution and homologous recombination in bacteria