Theory of high energy features in angle-resolved photo-emission spectra of hole-doped cuprates

The recent angle-resolved photoemission measurements performed up to binding energies of the order of 1eV reveals a very robust feature: the nodal quasi-particle dispersion breaks up around 0.3-0.4eV and reappears around 0.6-0.8eV. The intensity map in the energy-momentum space shows a waterfall like feature between these two energy scales. We argue and numerically demonstrate that these experimental features follow naturally from the strong correlation effects built in the familiar t-J model, and reflect the connection between the fermi level and the lower Hubbard band. The results were obtained by a mean field theory that effectively projects electrons by quantum interference between two bands of fermions instead of binding slave particles.Comment: 5 pages 2 fig

Mesh reinforced membrane and its wrinkling characteristics

Membrane structures have received a wide range of attention in applications of large-scale spacecrafts, such as inflated wing, light-than-air (LTA) airship and membrane antenna reflector, and so on. These spacecrafts need to be designed as high loading-efficiency components or structures, especially with high shape precision [1]. Therefore, some special processing and design should be done on the membranes so as to satisfy with special requirements, such as free wrinkle, ultralightweight, high shape precision, and high load-carrying ability, etc.. Several applications may give us good ideas to deal with abovementioned problems in membrane structures. One example is easy to be remembered, that is, the Super-Pressure Balloons (SPB) [2-4] covered by some ropes on membrane surface to make the balloon stable and strong. The similar considerations are also applied to some gossamer spacecraft components or structures, taking the Lunar habitat [5] as an example

Heavy metal contamination and physical barrier are main causal agents for the genetic differentiation of Perna viridis populations in Peninsular Malaysia

A total of 19 polymorphic microsatellite loci were used to analyze the levels of genetic variations for six geographical populations of green-lipped Perna viridis collected from the coastal waters of Peninsular Malaysia. In addition, the total soft tissues of all mussel populations were determined for heavy metals (Cd, Cu, Pb and Zn). FST values revealed that all the six populations of P. viridis in Peninsular Malaysia were categorized as showing 'moderate genetic differentiation' according to the classification of Wright (1978). Cluster analysis revealed that three populations which were located in the western part of the Johor Causeway were clustered differently from the other three populations located in the eastern part. Hierarchical F-statistics and cluster analysis indicated that the Johor Causeway which blocked the free flow of the pelagic larvae swimmers of P. viridis and a distinct effect of heavy metal contamination on the Kg. Pasir Puteh population, were the two main causal agents for the genetic differentiation of the P. viridis populations investigated in this study

Sorption removal of arsenic (V) by Sn-loaded poly(hydroxamic) acid chelating resin

Sorption conditions of arsenate ions onto Sn-loaded poly (hydroxamic acid) chelating resin (Sn-PHA) have been studied. Sorption isotherms data correlated well to the Langmuir model with maximum capacity of 38.46 mg g-1 at pH 2. Sorption process follows pseudo-second order kinetics. Intraparticle diffusion was found to take part in sorption processes. The free energy (E) was 11.18 kJ mol-1 which shows the sorption is an ion-exchange process. Thermodynamic parameters, ΔH°, ΔS° and ΔG° were also calculated from the experimental data. Standard heat of sorption was found to be endothermic and entropy change value was calculated to be positive. Negative ΔG° value indicates that the sorption process for the arsenic anions onto Sn-PHA is spontaneous

Structure of GrlR and the Implication of Its EDED Motif in Mediating the Regulation of Type III Secretion System in EHEC

Enterohemorrhagic Escherichia coli (EHEC) is a common cause of severe hemorrhagic colitis. EHEC's virulence is dependent upon a type III secretion system (TTSS) encoded by 41 genes. These genes are organized in several operons clustered in the locus of enterocyte effacement. Most of the locus of enterocyte effacement genes, including grlA and grlR, are positively regulated by Ler, and Ler expression is positively and negatively modulated by GrlA and GrlR, respectively. However, the molecular basis for the GrlA and GrlR activity is still elusive. We have determined the crystal structure of GrlR at 1.9 Å resolution. It consists of a typical β-barrel fold with eight β-strands containing an internal hydrophobic cavity and a plug-like loop on one side of the barrel. Strong hydrophobic interactions between the two β-barrels maintain the dimeric architecture of GrlR. Furthermore, a unique surface-exposed EDED (Glu-Asp-Glu-Asp) motif is identified to be critical for GrlA–GrlR interaction and for the repressive activity of GrlR. This study contributes a novel molecular insight into the mechanism of GrlR function