Quantum Phase Liquids-Fermionic Superfluid without Phase Coherence

We investigate the two dimensional generalized attractive Hubbard model in a bipartite lattice, and and a "quantum phase liquid" phase, in which the fermions are paired but don't have phase coherence at zero temperature, in analogy to quantum spin liquid phase. Then, two types of topological quantum phase liquids with a small external magnetic field-Z2 quantum phase liquids and chiral quantum phase liquids-are discussed.Comment: 7 pages, 2 figure

Characterisation of human H⁺-ATPase a4 subunit

The vacuolar H+-ATPase (or V-ATPases) are a family of ATP-dependent proton pumps that move protons across the plasma membrane at specialised sites such as kidney epithelial cells and osteoclasts, as well as acidifying intracellular compartments. The 100 kDa polytopic a subunit of this group of ATPases is suggested to play important roles in proton translocation, assembly, and targeting as well as coupling of ATP hydrolysis and proton transport of the V-ATPase. In man, different a subunit paralogues are encoded by four genes. ATP6V0A4 encodes a4, which is dominantly expressed apically in a-intercalated cells in both human and mouse kidney. I sought binding partners for a4 in order to address its potential role in the V-ATPase complex. Random peptide phage display analysis using a4's C terminus as a target protein revealed a consensus motif (WLELRP) with almost complete homology to part of the enzyme phosphofructokinase 1 (PFK-1). Activity of this enzyme is the rate-limiting step in glycolysis. Specificity of a4 binding to this peptide was confirmed by phage ELISA. Protein-protein interaction was further demonstrated by co-immunoprecipitation of a4 with PFK-1 from human kidney membrane proteins. An in vitro PFK-1 pull-down assay showed that this interaction is also true for the ubiquitously expressed a1 subunit. Finally, PFK-1 co-immunolocalised with a4 in α-IC in the collecting ducts of human kidney. These findings indicate a direct link between V-ATPase and glycolysis, via the C-terminus of the pump's a subunit, and suggest a novel regulatory mechanism between V-ATPase function and energy supply. This interaction between the a subunit and PFK-1 also provides new evidence that the C-terminus of this subunit lies cytoplasmically in vivo. Finally, SPR analysis suggests a possible alteration of the a4/PFK-1 interaction by the mutation (G820R) within the a4(C) region identified from a patient with rdRTA, providing a potential mechanism for disease

Topological Mid-gap States of Topological Insulators with Flux-Superlattice

In this paper based on the Haldane model, we study the topological insulator with superlattice of pi-fluxes. We find that there exist the mid-gap states induced by the flux-superlattice. In particular, the mid-gap states have nontrivial topological properties, including the nonzero Chern number and the gapless edge states. We derive an effective tight-binding model to describe the topological midgap states and then study the mid-gap states by the effective tight-binding model. The results can be straightforwardly generalized to other two dimensional topological insulators with flux-superlattice.Comment: 6 pages, 9 figure

Effects of sequencing computer-based instruction and lecture in learning function concepts of C programming language

This study investigated the effectiveness of a computer-based lesson used before versus after formal lecture and examined students\u27 difficulties in learning the function concepts of the C programming language. The subjects were fifteen university students who were randomly assigned to two treatment groups that received different instructional sequences. The subjects completed questionnaires, a pretest, the computer-based lesson and a posttest. During the experiment, students\u27 learning processes were observed, their program errors were recorded by the computer system, and some students\u27 reactions were video-taped;Results showed that students\u27 posttest scores were not significantly affected by whether the computer-based lesson was presented before or after the formal lecture. The study reported students\u27 difficulties in syntax, semantics, design and debugging of C programs on the function topics. Recommendations for programming instruction, such as providing appropriate examples, teaching design and debugging strategies and developing a notional machine , were discussed. Use of a team approach, interviews of students, use of think-aloud and investigations of students\u27 preferences were also made for future research